WorldWideScience

Sample records for daylighting artificial lighting

  1. Light + architecture. Daylight - artificial light - energy; Licht + Architektur. Tageslicht - Kunstlicht - Energie

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    The symposium intends to provide scientific and technical fundamentals for room lighting with daylight. Daylight deflection systems and artificial light control systems were analyzed for this purpose, and a catalogue of criteria was established. Planners were given tools for projecting daylight control systems. Builder-owners received the fundamentals for economic assessment of combined daylight and artificial light illumination systems, while industrial producers obtained information for further development to maturity and for marketing of daylight-dependent artificial light control systems. (GL)

  2. Light and architecture. Daylight - artificial light - energy; Licht und Architektur. Tageslicht - Kunstlicht - Energie

    Energy Technology Data Exchange (ETDEWEB)

    Wambsganss, M. (ed.) [ip5 ingenieurpartnerschaft, Karlsruhe (Germany)]|[Fachhochschule Rosenheim (Germany)

    2007-07-01

    The symposium intends to provide scientific and technical fundamentals for room lighting with daylight. Daylight deflection systems and artificial light control systems were analyzed for this purpose, and a catalogue of criteria was established. Planners were given tools for projecting daylight control systems. Builder-owners received the fundamentals for economic assessment of combined daylight and artificial light illumination systems, while industrial producers obtained information for further development to maturity and for marketing of daylight-dependent artificial light control systems. (GL)

  3. Adaptive integration of daylight and artificial lighting

    DEFF Research Database (Denmark)

    Petersen, Kjell Yngve

    2016-01-01

    Daylight is dynamic and dependent upon weather conditions; unfolding with both subtle and dramatic variations in qualities of light. Through a building’s apertures, daylight creates a connection between the space inside and the world outside. The aperture or window itself constitutes the frame...... with the world. In contrast to fluctuating daylight, a specific distinctive feature of artificial light has been – until very recently – its constancy in colour and intensity. However, by virtue of the technological convertibility of LEDs in concert with digital control systems, LEDs are capable of dynamically...... producing variations in colour and intensity in ways that correspond to our experiences of the daylight. Daylight and artificial lighting are thus positioned in a new relationship to one another. Metaphorically, one can think of the adaptive software as ‘digital weather’ – as a self-generating and shifting...

  4. Detailed simulations of lighting conditions in office rooms lit by daylight and artificial light

    DEFF Research Database (Denmark)

    Iversen, Anne

    In this thesis the effect on the annual artificial lighting demand is investigated by employing detailed simulations of lighting conditions in office rooms lit by daylight and artificial. The simulations of the artificial lighting demand is accomplished through daylight simulations in Radiance....... The detailed simulations includes studies of the resolution of different weather data sets in climate-based daylight modeling. Furthermore, influence of the electrical lighting demand by simulating with dynamic occupancy patterns is studied. Finally the thesis explores the influence of obstructions in an urban...... canyon on the daylight availability within the buildings, and hence on the energy consumption for artificial lights. The results from the thesis demonstrates that the effect on the outcome of the daylight simulations when simulating with typical weather data files for the location of Copenhagen...

  5. An Exploration into Integrating Daylight and Artificial Light via an Observational Instrument

    DEFF Research Database (Denmark)

    Petersen, Kjell Yngve; Søndergaard, Karin

    2015-01-01

    An Exploration into Integrating Daylight and Artificial Light via an Observational Instrument Daylight is dynamic and dependent upon weather conditions; unfolding with both subtle and dramatic variations in qualities of light. Through a building’s apertures, daylight creates a connection between...... abstract and blurred phenomena, these diffused luminous reflections rouse us into interactions with the world. In this book we are interested in identifying the qualitative parameters involved in the integration of dynamic artificial lighting and daylight; the latter being already highly dynamic by nature...... that examine how the dynamic artificial lighting in the observational instrument unfolds during the changing of the daylight situations that are generated by the weather outside. This research employs the concept of coupling between interior and exterior, in order to identify a spectrum of design parameters...

  6. Energy savings due to daylight and artificial lighting integration in office buildings in hot climate

    Energy Technology Data Exchange (ETDEWEB)

    Al-Ashwal, Nagib T. [Sana' a University, Sana' a (Yemen); Budaiwi, Ismail M. [King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

    2011-07-01

    Reducing energy consumption while maintaining acceptable environmental quality in buildings has been a challenging task for building professionals. In office buildings, artificial lighting systems are a major consumer of energy and can significantly contribute to building cooling load. Furthermore, although reliable, artificial lighting does not necessarily provide the required quality of lighting. Significant improvement in lighting quality and energy consumption can be achieved by proper integration of daylight and artificial lighting. The objective of this study is to investigate the energy performance of office buildings resulting from daylight and artificial lighting integration in hot climates. A parametric analysis is conducted to find the impact of different window design parameters, including window area, height and glazing type, on building energy performance. Results have shown that as much as 35% reduction in lighting energy consumption and 13% reduction in total energy consumption can be obtained when proper daylighting and artificial lighting integration is achieved.

  7. Estimation Methodology for the Electricity Consumption with the Daylight- and Occupancy-Controlled Artificial Lighting

    DEFF Research Database (Denmark)

    Larsen, Olena Kalyanova; Jensen, Rasmus Lund; Strømberg, Ida Kristine

    2017-01-01

    Artificial lighting represents 15-30% of the total electricity consumption in buildings in Scandinavia. It is possible to avoid a large share of electricity use for lighting by application of daylight control systems for artificial lighting. Existing methodology for estimation of electricity...... consumption with application of such control systems in Norway is based on Norwegian standard NS 3031:2014 and can only provide results from a rough estimate. This paper aims to introduce a new estimation methodology for the electricity usage with the daylight- and occupancy-controlled artificial lighting...

  8. From dark to bright: novel daylighting applications in solid state lighting

    Science.gov (United States)

    Adler, Helmar G.

    2011-10-01

    The term "daylighting" is used in various ways, on one hand in a more architectural sense, i.e. using existing daylight to illuminate spaces, and on the other, more recently, for using light sources to replicate daylight. The emergence of solid state lighting (SSL) opens up a large number of new avenues for daylighting. SSL allows innovative controllability of intensity and color for artificial light sources that can be advantageously applied to daylighting. With the assistance of these new technologies the combination of natural and artificial lighting could lead to improvements in energy savings and comfort of living beings. Thus it is imperative to revisit or even improve daylighting research so that building networks of the future with their sensor, energy (e.g. HVAC) and lighting requirements can benefit from the emerging capabilities. This paper will briefly review existing daylighting concepts and technology and discuss new ideas. An example of a tunable multi-color SSL system will be shown.

  9. Alternatives to Outdoor Daylight Illumination for Photodynamic Therapy—Use of Greenhouses and Artificial Light Sources

    Directory of Open Access Journals (Sweden)

    Catharina M. Lerche

    2016-02-01

    Full Text Available Daylight-mediated photodynamic therapy (daylight PDT is a simple and pain free treatment of actinic keratoses. Weather conditions may not always allow daylight PDT outdoors. We compared the spectrum of five different lamp candidates for indoor “daylight PDT” and investigated their ability to photobleach protoporphyrin IX (PpIX. Furthermore, we measured the amount of PpIX activating daylight available in a glass greenhouse, which can be an alternative when it is uncomfortable for patients to be outdoors. The lamps investigated were: halogen lamps (overhead and slide projector, white light-emitting diode (LED lamp, red LED panel and lamps used for conventional PDT. Four of the five light sources were able to photobleach PpIX completely. For halogen light and the red LED lamp, 5000 lux could photobleach PpIX whereas 12,000 lux were needed for the white LED lamp. Furthermore, the greenhouse was suitable for daylight PDT since the effect of solar light is lowered only by 25%. In conclusion, we found four of the five light sources and the greenhouse usable for indoor daylight PDT. The greenhouse is beneficial when the weather outside is rainy or windy. Only insignificant ultraviolet B radiation (UVB radiation passes through the greenhouse glass, so sun protection is not needed.

  10. Alternatives to Outdoor Daylight Illumination for Photodynamic Therapy—Use of Greenhouses and Artificial Light Sources

    DEFF Research Database (Denmark)

    Lerche, Catharina; Heerfordt, Ida M; Heydenreich, Jakob

    2016-01-01

    to photobleach protoporphyrin IX (PpIX). Furthermore, we measured the amount of PpIX activating daylight available in a glass greenhouse, which can be an alternative when it is uncomfortable for patients to be outdoors. The lamps investigated were: halogen lamps (overhead and slide projector), white light...... was suitable for daylight PDT since the effect of solar light is lowered only by 25%. In conclusion, we found four of the five light sources and the greenhouse usable for indoor daylight PDT. The greenhouse is beneficial when the weather outside is rainy or windy. Only insignificant ultraviolet B radiation...

  11. Hybrid daylight/light-emitting diode illumination system for indoor lighting.

    Science.gov (United States)

    Ge, Aiming; Qiu, Peng; Cai, Jinlin; Wang, Wei; Wang, Junwei

    2014-03-20

    A hybrid illumination method using both daylight and light-emitting diodes (LEDs) for indoor lighting is presented in this study. The daylight can be introduced into the indoor space by a panel-integration system. The daylight part and LEDs are combined within a specific luminaire that can provide uniform illumination. The LEDs can be turned on and dimmed through closed-loop control when the daylight illuminance is inadequate. We simulated the illumination and calculated the indoor lighting efficiency of our hybrid daylight and LED lighting system, and compared this with that of LED and fluorescent lighting systems. Simulation results show that the efficiency of the hybrid daylight/LED illumination method is better than that of LED and traditional lighting systems, under the same lighting conditions and lighting time; the method has hybrid lighting average energy savings of T5 66.28%, and that of the LEDs is 41.62%.

  12. Lighting control and dimensioning in integrated daylight systems

    Energy Technology Data Exchange (ETDEWEB)

    Halonen, L.; Eloholma, M.; Lehtovaara, J.

    1996-12-31

    The objective of this research was to find out the subjective and individual requirements for lighting control in connection with daylight utilization in indoor lighting. There is a great potential to use daylight in indoor lighting. This sets demands for the integrated daylight control systems, so that the indoor lighting can be optimized and demands of the users can be fulfilled. Control strategies should also take into account individual light needs, luminance balance and visual comfort. New lighting control systems and strategies such as vertical/horizontal illuminance ratio were studied. The incoming daylight may radically change the luminance distribution of the visual field and the effects of daylight on luminances of vertical surfaces may become especially noticeable. When daylight is utilized in indoor lighting, special care has to be taken to maintain the quality of the lighting of the visual environment. The windows become a potential source of discomfort glare in offices in uncontrolled daylight conditions. With the present methods it is not possible to evaluate discomfort glare caused by high surface luminances or windows. The results of this research do not support the opinion that low vision people in offices need more light than the normally sighted or that the illumination levels should be raised for low vision people. The rise of lighting levels from the present practice (task illuminance level 500 lux) in office work does not improve the visual performance of low vision people. In planning the visual environment for the low vision people care has to be taken on the direction of light. (7 refs.)

  13. Analysis and prediction of daylighting and energy performance in atrium spaces using daylight-linked lighting controls

    International Nuclear Information System (INIS)

    Chow, Stanley K.H.; Li, Danny H.W.; Lee, Eric W.M.; Lam, Joseph C.

    2013-01-01

    Highlights: ► Daylight-linked lighting control and energy performance for atrium is studied. ► Field measurement of automatic dimming control shows 93% energy saving. ► Field measurement of manual on–off control shows 95% energy saving. ► Atrium illuminance is correlated with daylight factor for energy saving prediction. - Abstract: In subtropical Hong Kong, a certain amount of electricity is used to create visually comfortable interior spaces through electric lighting, which is the second major electricity-consuming item in commercial buildings, accounting for 20–30% of total electricity use. The burning of fossil fuels for electricity generation has many adverse effects on the environment. Daylighting is an important and useful strategy for enhancing visual comfort and reducing the need for the electricity consumed by light fittings. The rational use of daylight through tools such as photoelectric lighting controls can effectively reduce buildings’ electricity consumption and the related pollutants and greenhouse gas emissions. Daylighting design techniques are often best demonstrated via field measurements that provide reliable operational and energy performance data for establishing design guidelines. An atrium provides an environmentally controlled indoor public space that introduces daylight into the hearts of large buildings. In circulation areas such as corridors, people expect the way ahead to be sufficiently lit and daylight-linked lighting controls can deliver excellent energy savings. This paper presents the daylighting and energy performance of an atrium space using daylight-linked lighting controls. The cost, energy and environmental issues related to various daylight illuminances are estimated and design implications are discussed

  14. Light and colours

    DEFF Research Database (Denmark)

    Volf, Carlo

    2011-01-01

    Often a dichotomy between daylight and artificial light is observed, often artificial lighting replaces daylight. In Denmark daylight is characterized partly by being "borrowed" half of the year, partly by having long transitions periods between the light and the dark (nautical and civil twilight......). For these reasons artificial lighting does not complement daylight but provides, coupled with the daylight, the total lighting in the indoor environment. Electric lighting is therefore ‐ in a complex interaction with the daylight ‐ of great importance for both our lighting and our wellbeing. Studying artificial...... lighting without studying daylight seem to be a common procedure of the practice of today in Denmark and other parts of the industrialized world. As a consequence of this artificial lighting suffers from a quantifying tyranny, a tyranny where the quality of light is measured in quantities. This procedure...

  15. Day-light-controlled artificial lighting a potential energy saver": right interior light by sky luninance trracking

    NARCIS (Netherlands)

    Rutten, A.J.F.; Mills, Evan

    1991-01-01

    The energy consumption in office buildings can considerably be cut, if daylight is used as task lighting. A conservative estimate - starting from existing knowledge and calculation methods - gives a potential saving of 460 GWh a year or 46 % of the electricity costs for artificial lighting in Dutch

  16. Sky luminance research imperative for adequate ciontrol of temporary supplementary artificial lighting installations

    NARCIS (Netherlands)

    Rutten, A.J.F.

    1994-01-01

    The energy consumption in Dutch office buildings can be cut considerably if daylight is used as task lighting. A conservative estimate gives a potential saving of 46% on the electricity costs for artificial lighting. The problem of photo-electric control of artificial lighting supplementing the

  17. Light and energy - daylight measurements

    Energy Technology Data Exchange (ETDEWEB)

    Christoffersen, Jens; Logadottir, A.; Traberg-Borup, S.; Barrie-Nielsen, K.

    2009-07-01

    All measurements where conducted in the spring of 2007, except the Interpane panel. The solar cell panels have been evaluated by three performance indicators to assess the daylight quantity within the room and the systems ability to maintain view to the outside. In the study, we used two performance indicators to assess the daylight quantity within the room: 1. the daylight factor (overcast sky) 2. the relative work plane illuminance (clear sky condition) Overcast sky: In general, all panels provided less daylight than the recommended requirement in the Danish Building Regulation of 2% on the work plane. This will most likely result in additional need for electric lighting. However, larger window areas and more parts of the facade with clear unobstructed glass may be one solution. Clear sky: In general, all panels provided less interior light levels than the two reference systems in the back of the room. Almost all systems aloud more or less direct sunlight in the window perimeter through the clear openings and additional needs for some kind of shading device is to be expected. Some systems blocked a large portion of the light in the majority of the room, and additional electric light in this part of the room may be needed. Only one performance indicator where used to describe the quality of the panels. View: In general, all panels, except two, obstruct the view significantly and cause figure/background confusion for a view position close to the window and the discrepancies of colour judgements. Only two systems provided a fairly clear view to the outside without to much distortion of the view. (au)

  18. Flat Optical Fiber Daylighting System with Lateral Displacement Sun-Tracking Mechanism for Indoor Lighting

    Directory of Open Access Journals (Sweden)

    Ngoc Hai Vu

    2017-10-01

    Full Text Available An essential impact which can improve the indoor environment and save on power consumption for artificial lighting is utilization of daylight. Optical fiber daylighting technology offers a way to use direct daylight for remote spaces in a building. However, the existing paradigm based on the precise orientation of sunlight concentrator toward the Sun is very costly and difficult to install on the roof of buildings. Here, we explore an alternative approach using mirror-coated lens array and planar waveguide to develop a flat optical fiber daylighting system (optical fiber daylighting panel with lateral displacement Sun-tracking mechanism. Sunlight collected and reflected by each mirror-coated lens in a rectangular lens array is coupled into a planar waveguide using cone prisms placed at each lens focus. This geometry yields a thin, flat profile for Sunlight concentrator. Our proposed concentrating panel can be achieved with 35 mm thickness while the concentrator’s width and length are 500 mm × 500 mm. The commercial optical simulation tool (LightToolsTM was used to develop the simulation models and analyze the system performance. Simulation results based on the designed system demonstrated an optical efficiency of 51.4% at a concentration ratio of 125. The system can support utilizing a lateral displacement Sun-tracking system, which allows for replacing bulky and robust conventional rotational Sun-tracking systems. This study shows a feasibility of a compact and inexpensive optical fiber daylighting system to be installed on the roof of buildings.

  19. Natural Light is the Right Light - Daylighting Design and Technology between Architecture, Art and Sustainability

    DEFF Research Database (Denmark)

    Osterhaus, Werner

    2009-01-01

    Within contemporary architecture, the art of daylighting design ? despite its many recognized advantages in comparison with electric lighting ? still encounters skepticism, primarily because it is usually developed and articulated more intuitively, rather than technically. Innovative daylighting ...... daylighting design with an open mind and an appreciation for basic human needs....... applications have added sparkle and interest to buildings. The sun?s rays have been captured to create magnificent plays of forms in light. People perceive daylight as an essential element of life. But architects, lighting designers, and clients alike, often underestimate the importance of daylight for human...

  20. Workplane Illuminance Estimation for Robust Daylight Harvesting Lighting Control

    NARCIS (Netherlands)

    Zhang, S.; Birru, D.

    2012-01-01

    Daylight harvesting lighting controls can provide significant energysavings in daylit spaces. However, their performance is affected bythe changing lighting distribution in the space due to window treatments and the sun. Such impacts reduce the field performance of daylight harvesting dimming

  1. Integration Issues for Using Innovative Daylighting Strategies in Light Wells

    Directory of Open Access Journals (Sweden)

    Gashinani M. Gholipour

    2017-12-01

    Full Text Available “Light well” as one of the most common means of daylight tolls in building, experiences severe limitations and deserve special attention. The question is which strategy is the best for increasing the daylight penetration to the depth of buildings. One of the main challenges in deep plan is to guide daylight into the building core and this can be performed through daylighting strategies, but the choice of the proper innovative daylighting system (IDS with several parameters is the problem. This paper aims to find elements for optimal choice and selecting context-compatible tools for light well. The result shows that four macro factors were found at the interaction of building and IDS. Identifying the integration components can play an effective role in decision-making or design a new tolls consistent with the physical conditions of light well and building to overcome the daylight crisis.

  2. The study on the computer analysis of solar daylighting system in the schoolroom

    Energy Technology Data Exchange (ETDEWEB)

    Oh, W. J.; Makhmudov, I.; Lee, Y. J.; Chun, W. G. [Jeju National University, Jeju (Korea, Republic of)

    2010-10-15

    Daylighting is the efficient use of natural light in order to minimize the need for artificial light in buildings. A well thought out building designed with daylighting can have a number of significant benefits for building owners and occupants. Increasing levels of daylight within rooms can reduce electrical lighting loads by up to 70% in some cases. In this study, the daylighting system using mini dish and optical fiber was analyzed for application to the schoolroom by the simulation of ECOTECT and RADIANCE

  3. ADASY (Active Daylighting System)

    Science.gov (United States)

    Vázquez-Moliní, Daniel; González-Montes, Mario; Fernández-Balbuena, Antonio Á.; Bernabéu, Eusebio; García-Botella, Ángel; García-Rodríguez, Lucas; Pohl, Wilfried

    2009-08-01

    The main objective of ADASY (Active Daylighting System) work is to design a façade static daylighting system oriented to office applications, mainly. The goal of the project is to save energy by guiding daylight into a building for lighting purpose. With this approach we can reduce the electrical load for artificial lighting, completing it with sustainable energy. The collector of the system is integrated on a vertical façade and its distribution guide is always horizontal inside of the false ceiling. ADASY is designed with a specific patent pending caption system, a modular light-guide and light extractor luminaire system. Special care has been put on the final cost of the system and its building integration purpose. The current ADASY configuration is able to illuminate 40 m2 area with a 300lx-400lx level in the mid time work hours; furthermore it has a good enough spatial uniformity distribution and a controlled glare. The data presented in this study are the result of simulation models and have been confirmed by a physical scaled prototype. ADASY's main advantages over regular illumination systems are: -Low maintenance; it has not mobile pieces and therefore it lasts for a long time and require little attention once installed. - No energy consumption; solar light continue working even if there has been a power outage. - High quality of light: the colour rendering of light is very high - Psychological benefits: People working with daylight get less stress and more comfort, increasing productivity. - Health benefits

  4. The costs and benefits of using daylight guidance to light office buildings

    Energy Technology Data Exchange (ETDEWEB)

    Mayhoub, M.S.; Carter, D.J. [School of Architecture, University of Liverpool (United Kingdom)

    2011-03-15

    Daylight guidance systems are linear devices that channel daylight into the core of a building. This paper analyses costs and benefits of using the two main classes of daylight guidance to light offices as an alternative to conventional electric lighting. The work demonstrates that daylight guidance is generally not economical using conventionally accepted measures of both cost and benefit. It is shown that if intangible benefits associated with the delivery of daylight to offices are included in an analysis, a more favourable balance of cost and benefit is obtained. The implications of this for practical use of the systems are discussed. (author)

  5. The Experience of Dynamic Lighting

    DEFF Research Database (Denmark)

    Petersen, Kjell Yngve; Kristensen, Ole

    2017-01-01

    of daylight openings and the experience of spatial form. However, current developments in LED light sources (light emitting diodes) and adaptive software control systems allow for an enhanced correlation between daylight and artificial lighting, where the variations of the daylight are dynamically...... supplemented by variations in the artificial lighting. The suggestion is to develop a particular type of Observational Instrument that situates detailed experiential investigations into the design potentials of integration of natural and artificial lighting, and thereby to enable differentiated dynamic...

  6. Comparative Study of Daylighting Calculation Methods

    Directory of Open Access Journals (Sweden)

    Mandala Ariani

    2018-01-01

    Full Text Available The aim of this study is to assess five daylighting calculation method commonly used in architectural study. The methods used include hand calculation methods (SNI/DPMB method and BRE Daylighting Protractors, scale models studied in an artificial sky simulator and computer programs using Dialux and Velux lighting software. The test room is conditioned by the uniform sky conditions, simple room geometry with variations of the room reflectance (black, grey, and white color. The analyses compared the result (including daylight factor, illumination, and coefficient of uniformity value and examines the similarity and contrast the result different. The color variations trial is used to analyses the internally reflection factor contribution to the result.

  7. Daylighting analysis of rooflights through model measurements in the artificial sky

    Energy Technology Data Exchange (ETDEWEB)

    Filetoht, Levente I. [University of Technnology and Economics, Budapest, Hungary (Hungary)

    2000-07-01

    In investigating the daylighting of rooflights, it can be assumed that they are behaving as luminaires-having a major role in the lighting features of the interior space. Until now there is not enough precise information on these daylighting systems, and because of this, it is difficult to predict precisely the quality and quantity of illuminance and the light distribution in the interior. The exact behavior of the rooflights are complex and sophisticated. Their features are based on their geometry, reflectance and transmittance of their non-transparent, transparent and translucent surfaces. The effect of these features can not be predicted of calculated using the traditional mathematical methods. I am investigating roof-lighting systems taking into account the complex effects of their parts, using a completely new method based on a series of model measurements under artificial sky. Investigating the roof-light as a complex system which consist of relatively large surfaces and the effects of surfaces on other surfaces. Considering the different illuminance fields of the different types of roof-lighting systems. I will be able to determine the light distribution and efficiency of the system as well. The results of this research will lead to the development of a new computer software which is beyond the scope of this paper. [Spanish] Al investigar la iluminacion de luz de dia de luces de techo puede suponerse que se estan comportando como luminarias teniendo un papel principal en las caracteristicas de iluminacion del espacio interior. Hasta ahora no existe ninguna informacion precisa de estos sistemas de iluminacion de dia y a causa de ello es dificil predecir con precision la calidad y cantidad de iluminancia y la distribucion de la luz en el interior. El comportamiento exacto de las luces de techo es complejo y sofisticado. Sus caracteristicas estan basadas en su geometria, reflectancia y trasmitancia de sus superficies no transparentes, transparentes y

  8. Daylight strategies for architectural studio facilities: the literature review

    Science.gov (United States)

    Othman, Muhammad Anas Bin; Azfahani Ahmad, Nur; Ajis, Azizah Md

    2017-05-01

    The implementation of daylighting strategies in buildings is a common aspect in architecture. However, due to the availability of inexpensive electricity, natural lighting strategies became insignificant, and been overlooked by designers. With the current concern over rapid increment on electricity cost, many designers now try to revitalized daylighting strategies in buildings. This includes educational buildings. In Malaysian cases, it is a norm that universities; especially during lecture and studio sessions, used artificial lighting throughout the day. Definitely, this is not parallel with the “green” aim made by the Government in the Malaysian Plan. Therefore, this paper aims to explore the impact of daylight strategies for educational studios in universities, by maximising the penetration of natural daylight into the space towards creating a more green-conducive studio. The paper review literature about the types, criteria and benefits of daylight strategies. This paper also presented a pilot study that has been performed in one university in Perak, Malaysia, by selecting architectural studios as the main subject.

  9. Impacts of orientation on daylighting in high-rise office buildings in Malaysia

    Directory of Open Access Journals (Sweden)

    AbdolHamid Mahdavi

    2015-12-01

    Full Text Available Orientation is one of the important factors in building design to use daylight and ‎conserve energy. Well-orientated buildings maximise daylight reception through ‎building facades and reduce the need for artificial lighting. Reasonable daylighting usage in office buildings is an important part of an architect’s designing process, which leads to lesser electricity consumption as well as providing a visual and thermal comfort for the occupants. Orientation is an important factor in passive design strategies. This paper focuses on the orientation effect on daylighting into office rooms. The research method of this study was simulation which is performed on a hypothetical model on a 25 storey high-rise office building in Malaysia. All simulations were carried out in the IES-VE software that uses RADIANCE program for illuminance calculations. To evaluate the daylight in various conditions, a new index SAZ was introduced which assesses daylight factor (DF and absolute Lux. Results showed similar SAZ in CIE overcast sky in various orientations; whereas, in sunny sky due to sun path in Malaysia, different results showed northern and southern rooms have the best illuminance distribution. However, the similar window form and size in four orientations lead to more energy consumption for artificial lighting and cooling loads.

  10. Computer Modeling of Daylight-Integrated Photocontrol of Electric Lighting Systems

    Directory of Open Access Journals (Sweden)

    Richard Mistrick

    2015-05-01

    Full Text Available This article presents a variety of different approaches to both model and assess the performance of daylight-integrated electric lighting control systems. In these systems, the output of a controlled lighting zone is based on a light sensor reading and a calibrated control algorithm. Computer simulations can consider the simulated illuminance data generated from both the electric lighting system and a daylight delivery system whose performance is addressed using typical meteorological year (TMY weather data. Photosensor signals and the operation of a control system’s dimming algorithms are also included. Methods and metrics for evaluating simulated performance for the purpose of making informed design decisions that lead to the best possible installed system performance are presented.

  11. Daylighting practices of the architectural industry (baseline results of a national survey)

    Energy Technology Data Exchange (ETDEWEB)

    Hattrup, M.P.

    1990-05-01

    A national survey of over 300 commercial design architects was conducted to develop baseline information on their knowledge, perceptions, and use of daylighting in commercial building designs. Pacific Northwest Laboratory conducted the survey for the US Department of Energy's (DOE) Office of Building and Community Systems (BCS). In the survey daylighting was defined as the intentional use of natural light as a partial substitute for artificially generated light. The results suggested that architects need to be educated about the true benefits of daylighting and the impacts it can have on a building's energy performance. Educational programs that will increase the architects' understanding and awareness of modern daylighting technologies and practices should be developed by utilities, stage agencies, and the federal government. If more architects can be made aware of the true effectiveness and positive attributes of daylighting systems and technologies, daylighting may be used in more commercial buildings. The results of the survey show that the more familiar architects feel they are with daylighting, the more they use daylighting. 3 refs., 19 tabs.

  12. Measuring light spectrum as a main indicator of artificial sources quality

    Directory of Open Access Journals (Sweden)

    Piotr Dąbrowski

    2015-05-01

    Full Text Available Objective: To compare different artificial light sources in different places where plant breeding is conduced. Methods: Measurements were conducted outdoor, in room, in greenhouse, under four panels with light emitting diodes, in phytotron, in dark room with various light sources and inside Sanyo versatile environmental chamber. The measurements were made by using SpectraPen SP100 (PSI, Czech Republic device. Results: Our result showed that spectrum measured outdoor during sunny day had only one peak at the wavelength of 485 nm (ca. 60000 relative units. On cloudy day, the trend of light spectrum curve was similar, but with lower values. At room conditions, the curve was more flat than outdoor. Under greenhouse conditions, the curve was similar to that measured outdoor. A few additional peaks on the curve appeared by adding high pressure sodium lamp. There were changes of curve under LED panels. Conclusions: It must be underlined that the most similar spectrum curve to daylight light has incandescent bulb and this light source should be preferred as support of daylight in greenhouses and as main source in phytotrons. Using high pressure sodium lamp in greenhouses as support of daylight cause increase in the red/far-red ratio and occurrence of a new peak on spectrum curve. The new possibilities are creating by LED panels with red and blue diodes.

  13. DAYLIGHTING PERFORMANCE OF HORIZONTAL LIGHT PIPE BRANCHING ON OPEN PLAN OFFICE SPACE

    Directory of Open Access Journals (Sweden)

    Feny ELSIANA

    2015-12-01

    Full Text Available For daylighting purpose, office buildings should have a shallow plan and increase the ratio of surface to building’s volume. However, intensive use of air-conditioning drives office building’s plan to be deep with a minimum surface to volume ratio. This leads to the presence of areas that have insufficient daylight level at the work plane. Considering limitations of some daylighting methods in distributing daylight to these areas, Horizontal Light Pipe (HLP was selected. The aim of this research was to evaluate and explain the effect of HLP branching on daylight quantity and distribution inside open plan office space. Experimental with simulation as a tool was used as the research method. HLP branching’s uniformity ratio, illuminance and Daylight Factor were compared with unbranching HLP, simultaneously with daylighting standards. Results showed that office space with HLP-L branching had higher daylight level than HLP-T branching, 296 lux and 295 lux, HLP-L and HLP-T, respectively. However, HLP-T branching distributed daylight more evenly than HLP-L branching, with uniformity ratio as 1.49:1 and 1.50:1, HLP-T and HLP-L, respectively. Both of them met the illuminance target value and uniformity at work plane. Light’s deflection and improvement amount of opening distribution decreased average illuminance and Daylight Factor up to 3.59%. Those also decreased uniformity of daylight inside the space.

  14. Architecture, energy and daylight. Study of seven buildings; Arkitektur, energi og dagslys. Undersoegelse af syv bygninger

    Energy Technology Data Exchange (ETDEWEB)

    Christoffersen, J.; Petersen, E.; Svensson, O.

    2001-07-01

    The purpose of this research project was to enhance the designer's knowledge for designing buildings, rooms and window openings which utilise daylight in such a way that aesthetic and functional requirements can be met and energy consumption for electric lighting can be reduced at the same time. It was not the purpose of the project to develop guidelines but only to demonstrate how good daylight conditions and energy conservation can be achieved. The daylight conditions in the seven selected buildings were registered and assessed by the panel on two field trips in the spring of 1999. During these visits, the research team registered the location of rooms, their orientation, windows, artificial lighting etc. After the field trips, the buildings were photographed and the research group performed measurements and analyses of the lighting conditions in the rooms. However, the quality of daylight cannot be determined based only on measurements. The four professionals therefore supplemented the measurements with a subjective evaluation. The study of these seven buildings led to a number of results that must be assumed to be generally valid. A main result is that good daylight conditions in no way prevents or impedes the creation of good architecture. On the contrary, quality of daylight creates both functional as well as aesthetically satisfactory architecture. In all the investigated buildings, the ratio of glass areas to floor area is highter than 10%. In Denmark, this ratio would ensure reasonable daylight access and a view out. However, when size of glass area and daylight measurements are compared, the relationship between them is not straight-forward. The quantity and quality of daylight in buildings depend on other factors too, such as the depth of window openings, solar shading devices, opposite buildings, outdoor vegetation etc. The study points out that there are no standard solutions of how to design facades and window openings which satisfy all

  15. Daylighting in linear atrium buildings at high latitudes

    Energy Technology Data Exchange (ETDEWEB)

    Matusiak, Barbara

    1998-12-31

    This thesis proposes new criteria for visual comfort based on knowledge of visual perception and a method for estimating the modelling ability of light by using inter-reflection calculations. Simplified calculations are presented for the daylight factor in linear building structures, using the projected solid angle principle, for uniform sky and for CIE overcast sky conditions. The calculations are compared with experimental results. Simple diagrams are created based on calculations of the mean daylight factor in rooms adjacent to a narrow street. These diagrams and presented formulas and tables can be used as a simple design tool. Daylighting strategies for linear atrium buildings at high latitudes are developed and examined. These strategies are divided into three groups: (1) the atrium space and facades as light conductor/reflector, (2) the glass roof as a light conductor, and (3) light reflectors on the neighbouring roof. The atrium space and facade strategies are subdivided into passive and active. The strategies connected to the glazed roof includes different configurations of glazing: horizontal, single pitched, double pitched, and the use of laser cut panels and prismatic panels in the glazed roof. The shapes of reflectors on the neighbouring roof are a flat reflector, a parabolic reflector and a parabolic concentrator. Strategies from all three groups are examined on a physical model of scale 1:20 in the artificial sky of mirror box type. Simulations with artificial sun have also been done. The results from model studies are compared with computer simulations. All the active daylighting systems designed for use in the atrium space or on the atrium facades have a huge potential for use in atrium buildings. From the strategies connected with the glazed roof the negatively sloped glass is found to be the best alternative for glazed roofs at high latitudes. Among the roof reflectors, the flat one performs best. 82 refs., 122 figs., 27 tabs.

  16. Effectiveness of daylighting design and occupant visual satisfaction in a LEED gold laboratory building

    Energy Technology Data Exchange (ETDEWEB)

    Hua, Ying; Oswald, Anne [Department of Design and Environmental Analysis, Cornell University, Ithaca, NY 14853 (United States); Yang, Xiaodi [School of Architecture, Carnegie Mellon University, Pittsburgh, PA 15213 (United States)

    2011-01-15

    Using daylight as primary light source has been widely recognized as an important strategy to reduce building energy demand and enhance indoor environment quality. However, to design and operate a building to make full use of daylight, which is a dynamic light source, to meet diverse occupant needs remains a challenge. This paper reports a post-occupancy study of the visual environment in a laboratory building on a university campus, and puts a spotlight on the building occupants as it examines the effectiveness of the daylighting design and systems integration in creating a visual environment to support occupant comfort and satisfaction while reducing artificial lighting demand. Results show generally high satisfaction with daylit work environment and positive effect of the horizontal shading strategy. Issues about the integration between daylighting and electric lighting systems and level of occupant control are identified and discussed for improving the effectiveness of daylighting and enhancing the quality of the visual environment in the building of study. A multiple-tool methodology is developed and tested, which included occupant surveys, interviews, illuminance measurements, continuous data loggers, fisheye-lens camera and glare-identifying software, and documentation of spatial settings, systems features, and user behavior. (author)

  17. Integrated control of sun shades, daylight and artificial light; Integreret regulering af solafskaermning, dagslys og kunstlys

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, K.; Christoffersen, J.; Soerensen, Henrik; Jessen, G.

    2011-07-01

    The project established a basis of calculation and a practical basis for optimum choice of solar shading and integrated control strategies for both new buildings and for office, commercial and institutional buildings to be renovated with new calculation models for controlling solar shading integrated in the BSim program. A complete and applicable model for optimum, integrated solar shading control was established, focusing on thermal and visual comfort criteria towards energy consumption for heating, cooling and lighting. A prototype was tested in the daylight laboratory at Danish Building Research Institute-Aalborg University and at University of Southern Denmark. (LN)

  18. Continuous ultra-low-intensity artificial daylight is not as effective as red LED light in photodynamic therapy of multiple actinic keratoses

    DEFF Research Database (Denmark)

    Wiegell, Stine Regin; Heydenreich, Jakob; Fabricius, Susanne

    2011-01-01

    Daylight-mediated photodynamic therapy (PDT) is a simple and tolerable treatment of nonmelanoma skin cancer. It is of interest which light intensity is sufficient to prevent accumulation of protoporphyrin IX (PpIX) and effectively treat actinic keratoses (AKs). We compared the efficacy of PDT...

  19. Glazing façade modules : daylighting performance simulation for Bragança, Coimbra, Évora and Faro

    OpenAIRE

    Sacht, Helenice Maria; Bragança, L.; Almeida, Manuela Guedes de; Caram, Rosana

    2012-01-01

    The daylighting performance improvement is one better strategy to reduce the artificial lighting consumption in buildings and obviously requires solar radiation from the exterior. Daylighting comes not only from direct sunlight but also from illumination provided by the sky on overcast days. Particular attention must be given to daylighting while designing a building when the aim is to maximize visual comfort or to reduce energy consumption. Visual comfort of glazing façades is a fundamental ...

  20. How to Frame Universal Workspace Lighting

    DEFF Research Database (Denmark)

    Mathiasen, Nanet; Frandsen, Anne Kathrine

    2016-01-01

    ; regardless of disability everybody should be able to move around in the house and work in any of the offices. One, of many ambitions, was to design a functional and effective lighting scheme using as much daylight as possible, and integrating the artificial lighting design and daylight design. The lighting...

  1. Modeling of lighting behaviour of a hybrid lighting system in inner spaces of Building of Electrical Engineering

    Science.gov (United States)

    Amado, L.; Osma, G.; Villamizar, R.

    2016-07-01

    This paper presents the modelling of lighting behaviour of a hybrid lighting system - HLS in inner spaces for tropical climate. HLS aims to mitigate the problem of high electricity consumption used by artificial lighting in buildings. These systems integrate intelligently the daylight and artificial light through control strategies. However, selection of these strategies usually depends on expertise of designer and of available budget. In order to improve the selection process of the control strategies, this paper analyses the Electrical Engineering Building (EEB) case, initially modelling of lighting behaviour is established for the HLS of a classroom and an office. This allows estimating the illuminance level of the mixed lighting in the space, and energy consumption by artificial light according to different lighting control techniques, a control strategy based on occupancy and a combination of them. The model considers the concept of Daylight Factor (DF) for the estimating of daylight illuminance on the work plane for tropical climatic conditions. The validation of the model was carried out by comparing the measured and model-estimated indoor illuminances.

  2. A review of daylight illuminance determinations and energy implications

    Energy Technology Data Exchange (ETDEWEB)

    Li, Danny H.W. [Building Energy Research Group, Department of Building and Construction, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR (China)

    2010-07-15

    Daylighting is recognized as an important element in architecture and a useful strategy in energy-efficient building designs. Daylight gives a sense of cheeriness and brightness that can have a significant positive impact on the people. There is a scope for integrating daylight with electric light to reduce building energy use. The amount of daylight entering a building is mainly through window openings, which create in the indoor environment a more attractive and pleasing atmosphere, in addition to maximise visual access to the pleasant views of the outside world. Determinations of the exterior and interior daylight and lighting energy savings are key issues to demonstrate the benefits based on daylighting designs. This paper provides a review of daylight illuminance determinations and the lighting energy reductions due to daylighting schemes. The study includes daylight measurements, prediction of daylight illuminance under various sky conditions and potential electric lighting energy savings from daylight-linked lighting controls. The article aims at providing building professionals, practitioners and researchers more information and a better understanding of daylight for promoting effective daylighting designs and evaluations. (author)

  3. Combined daylight and intelligent LED lighting - getting the daylight into the buildings; Kombineret dagslys og intelligent LED belysning - fae dagslys ind i bygningerne. Slutrapport

    Energy Technology Data Exchange (ETDEWEB)

    Dam-Hansen, C.; Corell, D.D.; Thorseth, A.; Behrensdorff Poulsen, P. [Technical Univ. of Denmark, DTU Fotonik, DTU Risoe Campus, Roskilde (Denmark); Markvart, J.; Iversen, A.; Logadottir, A. [Aalborg Univ., Statens Byggeforskningsinstitut (SBi), Koebenhavn (Denmark)

    2013-03-15

    The main result of the project is the construction of the new intelligent and dynamic LED lighting system for demonstration and research purposes, and a number of extensive user testing is completed. The LED lighting system is a total system for office lighting with ceiling fixtures and desk lamps, which has made it possible to create a general and workplace lighting in two offices each with two work places. The system is installed in a day light laboratory for such two office spaces. All lamps can be controlled via a developed computer interface, and the desk lamps are further manually controllable by a user via two buttons for color temperature and brightness, respectively. The new intelligent and dynamic lighting system is based on color mixing LED technology and makes it possible to control the color composition, color coordinates and thus the color temperature of the light. Control-wise, the system is pre-programmed to produce white light with a correlated color temperature from 2700 K to 7000 K. The color composition is optimized from the desire for a very good color given at a general CRI value of 92-97 over the area. The system can be dimmed 20-100 %, with no significant change in the light's color properties. A mini-spectrometer is calibrated and built-in in the system and provides the current estimate of daylight brightness and color temperature through measurement of daylight color scheme in the visible range. The system uses daylight properties to control the light from the LED lighting system. The results of user tests show, that the developed possibility to automatically control of light in the office depending on the daylight color temperature is considered to be equally preferred and results in equally satisfied users as a traditional lighting system with even lighting in the room. On the other hand, user results showed that there were both energy savings and more satisfied users to be gained by providing users the opportunity to self-adjust either

  4. Modeling daylight from solar irradiation in Malaysia

    International Nuclear Information System (INIS)

    Ahmed, A.Z.; Sayigh, A.A.K.; Surendran, P.N.; Othman, M.Y.

    1999-01-01

    The oil crises in the seventies, the environmental impact by the extensive use of energy in the nineties and the recent economic recession in Asia have led to the rediscovery of the use of daylight in energy-conscious design in buildings, the economic implication of the excessive use of artificial lighting in potential of daylight. No daylight data is currently available in Malaysia and therefore there is a need to model the daylight availability based on other climatic parameters measured at meteorological stations. A study has been carried out to produce daylight data from measured climatic parameters, specifically solar irradiation and could cover. The Model Year Climate (MYC) data for the location of Subang (3 deg. 7', N 101 deg. 33' E), model to estimate daily diffuse irradiation was produced the average values of global (KG) and diffuse (KD) luminous efficacious were calculated and found to be 112 lm/W and 120 lm/W respectively. The value of 104 lm/W for the beam luminous efficacy (KB) was selected. Using cloud data cover data as input parameters, the nebulosity index was calculated to determine the sky condition in Subang, Malaysia, which was then classified as average or intermediate sky type, the hourly illuminance on horizontal and inclined surfaces at locations with similar sky conditions in Malaysia were then produced. (author)

  5. Welcome to the Journal of Daylighting

    Directory of Open Access Journals (Sweden)

    Irfan Ullah

    2014-12-01

    Full Text Available I am delighted to welcome you to a newly launched Solarlits electronic journal: the Journal of Daylighting (JD. As the Editor-in-Chief of JD it is a great pleasure to introduce the inaugural issue of this new, open-access, bi-annual journal to readers, researchers, future authors, and colleagues. The decision by SolarLits to launch this new journal is very timely. Because the growth of lighting demand is increasing due to rising average illuminance levels in buildings, more attention has been paid to introduce daylighting in buildings, which will sustainably reduce the overall energy consumption in buildings. JD will serve as a new international platform for researchers to share advances in daylighting. As an international, peer-reviewed research journal it will exclusively cover the vibrant and diverse field of daylighting technologies and applications. JD will serve as an interdisciplinary forum for the scientific and research community active in daylighting and its applications. Topics will include, but not limited to: daylighting and hybrid lighting systems, lighting and daylighting simulation, lighting designs, lighting metrology and light quality, lighting control, building physics - lighting, building energy modeling, energy efficient buildings, zero-energy buildings, indoor environment quality, sustainable solar energy systems, application of solar energy sources in buildings, building-integrated photovoltaics, and solar thermal and concentrator technology. I will work with the Associate Editors, the Editorial Board, and the scientific and engineering research community to make JD a primary journal for the dissemination of breakthrough results, discussion of key challenges, and topics in daylighting. JD will publish full-length research articles, review articles, book reviews, and short communications.

  6. "Light and the aesthetics of the perception"

    DEFF Research Database (Denmark)

    Volf, Carlo

    2010-01-01

    through the meeting with form. Therefore, since form has been the major theme for the aesthetics up until now, giving form to light is a complex and challenging task and reducing it to Lux and measurable numbers only an escape from facing what is actually percieved. In this way light seems to suffer from...... this article tries to establish a dialogue between the daylight and the artificial lighting. The article describes how light - this intangible building block – can become a more workable size in the aesthetic and architectural practice of today. KEYWORDS Light, daylight, artificial light, aesthetics...

  7. Capturing the Daylight Dividend

    Energy Technology Data Exchange (ETDEWEB)

    Peter Boyce; Claudia Hunter; Owen Howlett

    2006-04-30

    Capturing the Daylight Dividend conducted activities to build market demand for daylight as a means of improving indoor environmental quality, overcoming technological barriers to effective daylighting, and informing and assisting state and regional market transformation and resource acquisition program implementation efforts. The program clarified the benefits of daylight by examining whole building systems energy interactions between windows, lighting, heating, and air conditioning in daylit buildings, and daylighting's effect on the human circadian system and productivity. The project undertook work to advance photosensors, dimming systems, and ballasts, and provided technical training in specifying and operating daylighting controls in buildings. Future daylighting work is recommended in metric development, technology development, testing, training, education, and outreach.

  8. Effects of accelerated artificial daylight aging on bending strength and bonding of glass fibers in fiber-embedded maxillofacial silicone prostheses.

    Science.gov (United States)

    Hatamleh, Muhanad M; Watts, David C

    2010-07-01

    The purpose of this study was to test the effect of different periods of accelerated artificial daylight aging on bond strength of glass fiber bundles embedded into maxillofacial silicone elastomer and on bending strength of the glass fiber bundles. Forty specimens were fabricated by embedding resin-impregnated fiber bundles (1.5-mm diameter, 20-mm long) into maxillofacial silicone elastomer. Specimens were randomly allocated into four groups, and each group was subjected to different periods of accelerated daylight aging as follows (in hours); 0, 200, 400, and 600. The aging cycle included continuous exposure to quartz-filtered visible daylight (irradiance 760 W/m(2)) under an alternating weathering cycle (wet for 18 minutes, dry for 102 minutes). Pull-out tests were performed to evaluate bond strength between fiber bundles and silicone using a universal testing machine at 1 mm/min crosshead speed. Also a three-point bending test was performed to evaluate bending strength of the fiber bundles. One-way ANOVA and Bonferroni post hoc tests were carried out to detect statistical significance (p aging only. After 200 hours of exposure to artificial daylight and moisture conditions, bond strength between glass fibers and heat-cured silicones is optimal, and the bending strength of the glass fiber bundles is enhanced.

  9. Economic feasibility of maximising daylighting of a standard office building with efficient electric lighting

    DEFF Research Database (Denmark)

    Fontoynont, Marc; Ramananarivo, Karine; Soreze, Thierry Silvio Claude

    2016-01-01

    This paper investigates the cost of developing various daylighting strategies for a standard office building in relation to their ability to reduce electric lighting consumption. The reference building design for this study corresponds to a typical configuration that minimises the construction...... costs and is typical of the French market. We have compared scenarios that entail moving service spaces to the periphery, increasing ceiling height and adding light wells of various shapes. These special features increased the proportion of the indoor area with sufficient daylight by up to 40...

  10. Daylight utilisation in office buildings

    DEFF Research Database (Denmark)

    Christoffersen, Jens

    This Ph.D. thesis presents the qualitative and quantitative consequences of full-scale measurements on two daylighting systems, light shelf and Venetian blinds. The systems were investigated to assess their ability to increase daylight penetration and improve daylight distribution in the interior...... the benefits and difficulties regarding use of daylight in office buildings, but it is hoped that the report will provide daylight conscious building design in forthcoming non-domestic buil dings....

  11. Investigating the Influence of Light Shelf Geometry Parameters on Daylight Performance and Visual Comfort, a Case Study of Educational Space in Tehran, Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Moazzeni

    2016-07-01

    Full Text Available Daylight can be considered as one of the most important principles of sustainable architecture. It is unfortunate that this is neglected by designers in Tehran, a city that benefits from a significant amount of daylight and many clear sunny days during the year. Using a daylight controller system increases space natural light quality and decreases building lighting consumption by 60%. It also affects building thermal behavior, because most of them operate as shading. The light shelf is one of the passive systems for controlling daylight, mostly used with shading and installed in the upper half of the windows above eye level. The influence of light shelf parameters, such as its dimensions, shelf rotation angle and orientation on daylight efficiency and visual comfort in educational spaces is investigated in this article. Daylight simulation software and annual analysis based on climate information during space occupation hours were used. The results show that light shelf dimensions, as well as different orientations, especially in southern part, are influential in the distribution of natural light and visual comfort. At the southern orientation, increased light shelf dimensions result in an increase of the area of the work plane with suitable daylight levels by 2%–40% and a significant decrease in disturbing and intolerable glare hours.

  12. Daylight Utilization with Light Pipe in Farm Animal Production: A Simulation Approach

    Directory of Open Access Journals (Sweden)

    Alejandro Pacheco Diéguez’

    2016-06-01

    Full Text Available Light pipes offer a passive way to bring daylight inside deep buildings, such as agricultural buildings. However, the lack of reliable performance predictability methods for light pipes represents a major obstacle preventing their widespread use. This paper evaluates a simulation approach for performance prediction and identifies key light pipe design parameters affecting their daylight transmission performance. The study was carried out through continuous monitoring of daylight in two full-scale, identical pig stables fitted with two light pipe systems, Solatube® and Velux®. The experiment included three continuously measuring sensors in each stable and an outdoor sensor during 2013 and 2014. A forward raytracing tool, TracePro®, was used for illuminance prediction and parametric simulations. The simulation results for overcast skies indicated discrepancies between the simulated and average measurement results below 30% in all cases. The discrepancies for clear skies were somewhat higher, i.e., below 30% for 67% of the cases. The higher discrepancies with clear skies were due to the overestimation of absolute sunlight levels and absence of an advanced and detailed optical characterization of the dome collector’s surface. The parametric results have shown that light pipes’ performance is better during summer time, in sunny climates, at low to mid-latitudes, which provides higher solar altitudes than during winter and cloudy climates at high latitudes. Methods to improve the luminous transmittance for low solar altitudes occurring in Scandinavia include: bending or tilting the pipe, increasing the aspect ratio, improving the pipe specular reflectance, tilting the collector to the south, and using optical redirecting system in the collector.

  13. Dawn song in natural and artificial continuous day: Light pollution affects songbirds at high latitudes.

    Science.gov (United States)

    Derryberry, Elizabeth P

    2017-10-01

    In Focus: Da Silva, A., & Kempenaers, B. (2017). Singing from North to South: Latitudinal variation in timing of dawn singing under natural and artificial light conditions. Journal of Animal Ecology, 86, 1286-1297. doi: 10.1111/1365-2656.12739 Satellite images of the world at night show bright dots connected by glowing lines crisscrossing the globe. As these connect-the-dots become brighter and expand into more and more remote regions, much of the flora and fauna of the world are experiencing evolutionarily unprecedented levels of light at night. Light cues are essential to most physiological and behavioural processes, and so the need to measure the effects of light pollution on these processes is critical. In this issue, Da Silva and Kempenaers take on this task using an important reproductive behaviour in songbirds-dawn song. The geographic, temporal and taxonomic breadth of sampling in this study allows for a close examination of a potentially complex interaction between light pollution and natural variation in the behaviour of dawn singing across latitude, season and species. Their extensive dataset highlights complexity in how songbirds respond to light pollution. Although light pollution has a strong effect on the timing of dawn song, not all songbirds respond the same way to light pollution, and the effects of light pollution vary with changes in natural light levels. Early dawn singers show more flexibility in the timing of dawn song across the season and across latitudes than late dawn singers, and also appear less affected by light pollution at high latitudes than are late dawn singers. These findings suggest that not all songbirds are responding to artificial continuous daylight as they do to natural continuous daylight, highlighting the general need to measure the fitness effects of light pollution. © 2017 The Author. Journal of Animal Ecology © 2017 British Ecological Society.

  14. Application of a spectral sky in Radiance for daylighting calculations including non-image-forming light effects

    NARCIS (Netherlands)

    Khademagha, P.; Aries, M.B.C.; Rosemann, A.L.P.; van Loenen, E.J.

    2016-01-01

    Daylight is dynamic and rich in the blue part of the spectrum. To date, the spectral composition of daylight is ignored in sky models used in Radiance. Spectral sky composition is particularly important when non-image-forming (NIF) light effects are concerned, since the action spectrum for these

  15. Glazing for intelligent daylight utilisation; Verglasungen fuer die intelligente Tageslichtnutzung

    Energy Technology Data Exchange (ETDEWEB)

    Rubbert, F. [VEGLA Vereinigte Glaswerke GmbH, Aachen (Germany)

    1999-10-01

    Daylight, a part of the solar energy incident on the Earth`s surface, is available to us for free and usually in sufficient quantity. Nevertheless, in office and administration buildings artificial lighting is used for an average 60% of total occupancy time. This figure refers not only those times of the year and day when daylight intensity is naturally weak but also includes periods when sunlight is available in excess. To minimise buildings` absorption of solar energy (and so reduce the cooling load) and shield workplaces against direct sunlight, frequent use is made of mechanical shading systems which necessitate the use of artificial lighting, this in turn adding to the cooling load. Several daylight systems have been developed and are now increasingly being used to resolve this paradoxical situation. [Deutsch] Tageslicht, als Bestandteil der Sonnenenergie, steht uns taeglich kostenlos und meistens in ausreichender Menge zur Verfuegung. Dennoch wird in Buero- und Verwaltungsgebaeuden die kuenstliche Beleuchtung im Durchschnitt waehrend etwa 60% der Nutzungszeit eingeschaltet. Dies jedoch nicht nur waehrend der tages- und jahreszeitlich bedingten Phasen mit einer geringen natuerlichen aeusseren Beleuchtungsstaerke, sondern gerade auch zu den Zeiten in denen Sonnenlicht im Uebermass zur Verfuegung steht. Denn zur Minimierung der in die Gebaeude eingebrachten solaren Energie (Reduzierung der Kuehllasten) und zur Erzielung eines Blendschutzes an den betroffenen Arbeitsplaetzen werden sehr haeufig mechanische Verschattungssysteme benutzt, die ein Zuschalten der kuenstlichen Beleuchtung erforderlich machen und somit wieder zu einer Erhoehung der Kuehllasten fuehren. Um dieser Parodoxie aufzuloesen, wurden einige Tageslichtsysteme entwickelt, die im zunehmenden Masse auch praktisch angewandt werden. (orig.)

  16. Analysis of Daylight Control in a Chateau Interior

    Directory of Open Access Journals (Sweden)

    Jitka Mohelníková

    2018-05-01

    Full Text Available Assessment of daylighting in the residential hall of a historical chateau is presented. The evaluation is based on both the daylight measurement and simulations. Illuminance levels in the interior were controlled in accordance with requirements for light exposition of light sensitive materials. Valuable paintings and claddings as well as wallpapers and furniture upholstery in the hall are extremely light sensitive and they need to be protected from light damage. The daylight measurements and simulations give an overview of daylight conditions in the annual profile for clear sky conditions and for different levels of window shadings.

  17. Effect of daylight saving time on lighting energy use: a literature review

    NARCIS (Netherlands)

    Aries, M.B.C.; Newsham, G.R.

    2008-01-01

    The principal reason for introducing (and extending) daylight saving time (DST) was, and still is, projected energy savings, particularly for electric lighting. This paper presents a literature review concerning the effects of DST on energy use. Simple estimates suggest a reduction in national

  18. Energy efficient lighting design for Venlo type greenhouses

    NARCIS (Netherlands)

    Janssen, E.G.O.N.; Zonneveldt, L.; Sools, F.

    2005-01-01

    TNO has developed a Radiance software model to calculate the light distribution in the greenhouse using raytracing methods, suitable for daylight and artificial lighting. The model is based on a 3d CAD model. The objective is to maximize the efficiency of the artificial lighting system (the amount

  19. How Can a Lighting Designer Use Light in Buildings For Well-Being? - 'Presented as invited speaker'

    DEFF Research Database (Denmark)

    Christoffersen, Jens

    design. Summary: Adequate lighting, both natural and artificial, is important as part of a person's well-being. A description of a person's well-being may be context-specific depending on the building design and include a number of parameters such as daylight and sunlight penetration, window views...... and content of view, enclosed or open space, crowding, visual and acoustical privacy, personal control of ambient conditions etc. Successful daylighting requires trade-offs and optimisation between competing design aspects by skilful integration of the facade layout with the space configuration and the choice...... of lighting system used.  Surveys consistently show that people prefer daylight over electric light, a desire for windows and view is well-established, and daylight as primary source is believed to be more healthful. Also, work spaces often consist of changing visual tasks, and thereby different lighting...

  20. The New York Times headquarters daylighting mockup: Monitoredperformance of the daylighting control system

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eleanor S.; Selkowitz, Stephen E.

    2006-02-24

    A nine-month monitored field study of the performance of automated roller shades and daylighting controls was conducted in a 401 m{sup 2} unoccupied, furnished daylighting mockup. The mockup mimicked the southwest corner of a new 110 km{sub 2} commercial building in New York, New York, where The New York Times will be the major tenant. This paper focuses on evaluating the performance of two daylighting control systems installed in separate areas of an open plan office with 1.2-m high workstation partitions: (1) Area A had 0-10 V dimmable ballasts with an open-loop proportional control system and an automated shade controlled to reduce window glare and increase daylight, and (2) Area B had digital addressable lighting interface (DALI) ballasts with a closed-loop integral reset control system and an automated shade controlled to block direct sun. Daylighting control system performance and lighting energy use were monitored. The daylighting control systems demonstrated very reliable performance after they were commissioned properly. Work plane illuminance levels were maintained above 90% of the maximum fluorescent illuminance level for 99.9{+-}0.5% and 97.9{+-}6.1% of the day on average over the monitored period, respectively, in Areas A and B. Daily lighting energy use savings were significant in both Areas over the equinox-to-equinox period compared to a non-daylit reference case. At 3.35 m from the window, 30% average savings were achieved with a sidelit west-facing condition in Area A while 50-60% were achieved with a bilateral daylit south-facing condition in Area B. At 4.57-9.14 m from the window, 5-10% and 25-40% savings were achieved in Areas A and B, respectively. Average savings for the 7-m deep dimming zone were 20-23% and 52-59% for Areas A and B, respectively, depending on the lighting schedule. The large savings and good reliability can be attributed to the automatic management of the interior shades. The DALI-based system exhibited faulty behavior that

  1. TCM in lighting design : an integrative medical methodology in light research

    NARCIS (Netherlands)

    Pan, Y.; Zielinska-Dabkowska, Karolina M.; Rohde, Michael F.

    2017-01-01

    The advancement of artificial lighting technology has enabled a lifestyle free from the restriction of natural daylight. However, scientists have discovered that light, assisting the cardiovascular system and synchronizing the biological clock, is a vital form of energy and information to sustain

  2. Economic analysis of the daylight-linked lighting control system in office buildings

    Energy Technology Data Exchange (ETDEWEB)

    Yang, In-Ho; Nam, Eun-Ji [Department of Architectural Engineering, College of Engineering, Dongguk University, 26-3, Pil-dong, Chung-gu, Seoul 100-715 (Korea)

    2010-08-15

    The objective of this study is to perform an economic analysis of the daylight-linked automatic on/off lighting control system installed for the purpose of energy savings in office buildings. For this, a building was chosen as a typical example, and the energy cost was calculated by using the daylight and building energy analysis simulation. When the lighting control was utilized, an economic analysis was performed using a payback period that was calculated by comparing the initial cost of installing the lighting control system with the annual energy cost which was reduced thanks to the application of the lighting control. The results showed that the lighting energy consumption, when the lighting control was applied, was reduced by an average of 30.5% compared with the case that there was not lighting control applied. Also, the result for total energy consumption showed that, when lighting control was applied, this was reduced by 8.5% when the glazing ratio was 100%, 8.2% for 80%, and 7.6% for 60% when compared to non-application. The payback period was analyzed in terms of the number of floors in a building; 10 floors, 20 floors, 30 floors, and 40 floors. Hence, the building with 40 floors and glazing ratio 100% resulted in the shortest payback period of 8.8 years, the building with 10 floors and glazing ratio 60% resulted in the longest period of 12.7 years. In other words, the larger the glazing ratio and the number of building floors are, the shorter the payback period is. (author)

  3. Daylight Management in Mediterranean Cities: When Shortage Is Not the Issue

    OpenAIRE

    Judit Lopez-Besora; Glòria Serra-Coch; Helena Coch; Antonio Isalgue

    2016-01-01

    Natural resources such as daylight and sunlight are highly appreciated in countries with prevailing overcast skies. Taking advantage of this scarce resource contributes to saving energy on artificial lighting. In contrast to northern, southern European cities are distinguished by a large number of days with direct sunlight caused by a propitious climate condition. While it is a positive issue in terms of energy availability, the abundance of it can be counterproductive if management measures ...

  4. Energy efficient lighting design for Venlo type greenhouses

    NARCIS (Netherlands)

    Janssen, E.; Zonneveldt, L.; Sools, F.

    2006-01-01

    TNO has developed a Radiance software model to calculate the light distribution in the greenhouse using raytracing methods, suitable for daylight and artificial lighting. The model is based on a 3D CAD (Computer aided design) model. The objective is to maximize the efficiency of the artificial

  5. Placing rooms in the right light. Targeted daylight and optimised artificial lighting help to improve comfort; Raeume ins richtige Licht ruecken. Gezielt eingesetztes Tageslicht und optimierte kuenstliche Beleuchtung helfen, das Wohlbefinden zu verbessern

    Energy Technology Data Exchange (ETDEWEB)

    Durst, Anna

    2012-11-01

    Regardless whether in the office, at home or in school, too little daylight or unfavourable lighting impair visibility in rooms and strain the eyes. Based on the example of schools and homes for the elderly, it was investigated how new lighting concepts and new lamp, luminaire and ballast technology can help to improve the situation. A measurement system was used to monitor the lighting and energy properties. The new lighting systems and optimised technology enabled the electrical energy requirements in a school to be reduced by around two thirds. (orig.)

  6. Daylight photodynamic therapy for actinic keratosis

    DEFF Research Database (Denmark)

    Wiegell, Stine; Wulf, H C; Szeimies, R-M

    2011-01-01

    clinic visits and discomfort during therapy. In this article, we critically review daylight-mediated PDT, which is a simpler and more tolerable treatment procedure for PDT. We review the effective light dose, efficacy and safety, the need for prior application of sunscreen, and potential clinical scope...... of daylight-PDT. Three randomized controlled studies have shown that daylight-mediated PDT is an effective treatment of thin AKs. Daylight-mediated PDT is nearly pain-free and more convenient for both the clinics and patients. Daylight-mediated PDT is especially suited for patients with large field......-cancerized areas, which can easily be exposed to daylight. Further investigations are necessary to determine at which time of the year and in which weather conditions daylight-mediated PDT will be possible in different geographical locations....

  7. Advanced fenestration and daylighting systems

    Energy Technology Data Exchange (ETDEWEB)

    McCluney, R. [Florida Solar Energy Centere, Cocoa, FL (United States)

    1998-09-01

    Advanced fenestration systems are new high-performance glazing and reflecting systems for otherwise conventional windows which offer specialized spectral and /or angular selectivity to provide improved illumination quantity and quality under optimal human comfort and energy conservation conditions. Advanced daylighting systems include systems manufactured by the solar lighting industry to introduce daylight into the core spaces of multi-storey buildings, spaces distant from the building envelope, or other locations where more conventional daylighting apertures cannot be placed. Details of operating, energy and illumination performance characteristics of both these systems were provided. It was concluded that solar lighting systems can effectively provide daylight illumination to interior spaces of a building that are not amenable to more conventional systems. Nevertheless, techniques need to be developed to predict the performance of such systems prior to their being built, so as to provide designers better means for justifying their use and economic viability, and to develop codes and performance standards to protect the consumer in the marketplace. 20 refs., 12 figs.

  8. Balancing energy and daylighting performances for envelope design: A new index and proposition of a case study in Hong Kong

    International Nuclear Information System (INIS)

    Xie, Jing Chao; Xue, Peng; Mak, Cheuk Ming; Liu, Jia Ping

    2017-01-01

    Highlights: •Daylighting and energy performances were studied simultaneously. •Energy demands of lighting and air-conditioning systems were both included. •Luminous comfort was quantified by Ave. DA 300 with the range from 29.6% to 57.8%. •Energy Daylight Rate was proposed as a simple multi-objective optimization approach. •Optimal scenarios for all directions were tested and chosen by EDR method. -- Abstract: Being healthy and energy saving have become two important principles of building development. Daylight is an influential factor with the characteristics of both photometry and radiometry. Irradiance brings solar heat gains that transfer to building cooling load, while illuminance provides a luminous environment and affects artificial lighting system at the same time. To balance the energy and daylighting performances, it is reasonable to minimize the environmental load under moderate comfort conditions. This study first quantified luminous comfort with a dynamic daylighting metric, average daylight autonomy (Ave. DA 300 ), from a questionnaire survey and simulation work. The benchmark of this metric should range from 29.6% to 57.8% for high-rise residential buildings. With this guideline, the Hong Kong public housing units is found that part of units lack of daylight due to the high building floor and density, while some units have potential to save energy by compromising daylighting performance. Therefore, a new index, energy daylight rate (EDR), is proposed to help decide the best scenario of envelope design for both daylighting and shading purposes. The results show that opening a secondary window is an efficient way to bring more light in and lengthening overhang is an efficient way to block excessive sunlight. This method and the new index are proved to have the ability to help defining proper building envelope design at the early stage.

  9. Light protection of the skin after photodynamic therapy reduces inflammation

    DEFF Research Database (Denmark)

    Petersen, B; Wiegell, S R; Wulf, H C

    2014-01-01

    whether protection with inorganic sunscreen, foundation or light-blocking plaster after PDT can reduce inflammation caused by daylight-activated PpIX. METHODS: On the right arm of 15 subjects with sun-damaged skin, four identical squares (3 × 3 cm) were given conventional PDT treatment. Immediately after...... red-light illumination the squares were either left unprotected or protected by inorganic sunscreen [sun protection factor (SPF) 50], foundation (SPF50) or light-blocking plaster. The skin was then illuminated with artificial daylight for 2 h and afterwards covered for 24 h. Fluorescence and erythema...... treatment was reduced by 19% with the sunscreen (P = 0·29), by 27% with the foundation (P = 0·10) and by 44% with the silver plaster (P = 0·002). CONCLUSIONS: Artificial daylight exposure after conventional PDT increases skin erythema. Light-blocking plaster gives more effective protection against post...

  10. Light-scattering properties of a Venetian blind slat used for daylighting applications

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, Annica M. [Department of Engineering Sciences, Angstroem Laboratory, Uppsala University (Sweden); Jonsson, Jacob C. [Environmental Energy Technology Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States)

    2010-12-15

    The low cost, simplicity, and aesthetic appearance of external and internal shading devices, make them commonly used for daylighting and glare-control applications. Shading devices, such as Venetian blinds, screens, and roller shades, generally exhibit light scattering and/or light redirecting properties. This requires the bi-directional scattering distribution function (BSDF) of the material to be known in order to accurately predict the daylight distribution and energy flow through the fenestration system. Acquiring the complete BSDF is not a straightforward task, and to complete the process it is often required that a model is used to complement the measured data. In this project, a Venetian blind slat with a white top surface and a brushed aluminum bottom surface was optically characterized. A goniophotometer and an integrating sphere spectrophotometer were used to determine the angle resolved and hemispherical reflectance of the sample, respectively. The acquired data were fitted to a scattering model providing one Lambertian and one angle dependent description of the surface properties. These were used in combination with raytracing to obtain the complete BSDFs of the Venetian blind system. (author)

  11. Practicality and Performance of Daylight Trough in The Tropics: A Case Study

    Directory of Open Access Journals (Sweden)

    Gene-Harn Lim

    2016-01-01

    Full Text Available The field of office daylighting is vital for both energy efficiency practice and occupants’ visual comfort. With the emergence of green building in Malaysia, building designers are exploring avenues for energy efficiency design; one common strategy is daylighting. The majority literature reviews on daylighting are skewed towards temperate or developed countries, where sky luminous condition is different from that of the Tropics. Conventional daylighting system designs redirect daylight from the envelope or atrium openings, such as light shelves. Presumed to be the pioneer daylight trough in the Tropics, this paper presents the simulated and in-situ lighting level measurements prior to occupancy. This case study presents an as-built daylight trough design which is able to daylight the office space as deep as 6 meters sufficiently. It achieves a lighting power density 1.90W/m2 and saves 39.2% of lighting energy over conventional office lighting energy. Discussed further is the practicality of working with such a system, including cost implication, return on investment and contractual challenges in reaching a consensus on the design. The results reinforce that the effectiveness of daylighting design is very dependable on the sun path and obstacles surrounding the office tower. The RADIANCE simulation correlates well to field measurement results. Further investigation into the light trough, its lighting energy savings, users’ interaction, visual comfort, and glare is still ongoing.

  12. Investigation of Educational Buildings in Terms of Daylighting Performance

    Directory of Open Access Journals (Sweden)

    İlknur ERLALELİTEPE

    2011-01-01

    Full Text Available Educational buildings have the priority among other building types in daylight performance studies. There are several reasons for this. Classrooms which are used during the whole day should have sufficient and homogeneously distributed daylight. In insufficient daylight conditions, the use of electrical lighting increases energy consumption. Users’ visual comfort should also be assured, and design incorporating natural light requires the analysis of sun protection devices in order to avoid glare and excessive heat. Also, atriums and skylights can be included in the building design with the aim of distributing light equally and in a relatively balanced manner throughout the building. However, lighting schemes are often proposed by architects and professionals who tend to make use of different design tools, and it would be pertinent to investigate whether these tools perform as desired. This study analyses daylight design principles and design elements in educational buildings. It outlines the method which has been used to analyse the daylight performance of buildings. A university building was selected for the field study. Measurements were taken in sample spaces to determine daylight performance. Utilising comparison between standard values and measured values, findings are presented in the form of tables, drawings and figures.

  13. Daylight Science and Daylighting Technology

    CERN Document Server

    Kittler, Richard; Darula, Stanislav

    2012-01-01

    Sunlight profoundly influences the Earth's atmosphere and biosphere. Nature fuels the evolution of all living things, their visual systems, and the manner in which they adapt, accommodate, and habituate. Sun luminance measurements serve as data to calculate typical changes in the daily, monthly, and annual variability characteristics of daylight. Climate-based sky luminance patterns are used as models in predicting daylighting calculation and computer programs applied in architecture and building design. Historically, daylight science and daylighting technology has prioritized photometric methods of measurements, calculation, and graphical tools aimed at predicting or evaluating the daylighting of architectural design alternatives. However, due to a heightened awareness of general health and well-being, sunlight exposure and freedom from visual discomfort while undertaking visual tasks are now equally prioritized. Therefore, in order to assure optimal environmental quality, daylighting technology must be base...

  14. The daylight alternative for energy conservation saving in lighting systems; La luz natural alternativa para el ahorro de energia en sistemas de iluminacion

    Energy Technology Data Exchange (ETDEWEB)

    Escutia Perez, A.; Cruz Mendez, E. P. [Universidad Autonoma Metropolitana, Unidad Azcapotzalco, Mexico D. F. (Mexico); Buitron Sanchez, H. [Programa de Ahorro de Energia del Sector Electrico, Mexico D. F. (Mexico)

    1995-12-31

    The technological advances generate far reaching changes in all types of installation. The new spaces and the existing ones justify the introduction of new technologies taking into account important economic considerations, mostly when the advantage of daylight is taken into consideration in industrial and commercial lighting. In the daylight design it is necessary to know the solar transit, the atmospheric conditions, the architectural design of the building, the materials and the control elements, etc. to apply with precision the calculation method. The fundamental lighting technic have varied little. In the greatest part of commerces and industries the general lighting is used, that produces an illumination more or less uniform on the working areas, which guarantees a total freedom for the placement of machinery, working benches, racks, exhibitors, clothes racks, etc.. This type of lighting is obtained by means of the use of a more or less regular series of skylights. The adequate localized lighting is used in those zones where because of the presence of obstructions or unfavorable slant of the working plan are not sufficiently well lighted by the general lighting system. The daylight use in accordance with the every moment availability will permit in many working centers a sensible diminution of the artificial lighting time, provided that the characteristics of the control operation of the installation permit it, along with modern controlling devices and the great variety of efficient saving lamps. [Espanol] Los avances tecnologicos generan cambios trascendentes en todo tipo de instalacion. Los nuevos espacios y los ya existentes justifican la introduccion de nuevas tecnologias teniendo consideraciones economicas importantes, sobre todo cuando se aprovecha la luz natural en sistemas de alumbrado industrial y comercial. En el diseno de iluminacion natural, es necesario tener el conocimiento del transito solar, las condiciones atmosfericas, el diseno

  15. The daylight alternative for energy conservation saving in lighting systems; La luz natural alternativa para el ahorro de energia en sistemas de iluminacion

    Energy Technology Data Exchange (ETDEWEB)

    Escutia Perez, A; Cruz Mendez, E P [Universidad Autonoma Metropolitana, Unidad Azcapotzalco, Mexico D. F. (Mexico); Buitron Sanchez, H [Programa de Ahorro de Energia del Sector Electrico, Mexico D. F. (Mexico)

    1996-12-31

    The technological advances generate far reaching changes in all types of installation. The new spaces and the existing ones justify the introduction of new technologies taking into account important economic considerations, mostly when the advantage of daylight is taken into consideration in industrial and commercial lighting. In the daylight design it is necessary to know the solar transit, the atmospheric conditions, the architectural design of the building, the materials and the control elements, etc. to apply with precision the calculation method. The fundamental lighting technic have varied little. In the greatest part of commerces and industries the general lighting is used, that produces an illumination more or less uniform on the working areas, which guarantees a total freedom for the placement of machinery, working benches, racks, exhibitors, clothes racks, etc.. This type of lighting is obtained by means of the use of a more or less regular series of skylights. The adequate localized lighting is used in those zones where because of the presence of obstructions or unfavorable slant of the working plan are not sufficiently well lighted by the general lighting system. The daylight use in accordance with the every moment availability will permit in many working centers a sensible diminution of the artificial lighting time, provided that the characteristics of the control operation of the installation permit it, along with modern controlling devices and the great variety of efficient saving lamps. [Espanol] Los avances tecnologicos generan cambios trascendentes en todo tipo de instalacion. Los nuevos espacios y los ya existentes justifican la introduccion de nuevas tecnologias teniendo consideraciones economicas importantes, sobre todo cuando se aprovecha la luz natural en sistemas de alumbrado industrial y comercial. En el diseno de iluminacion natural, es necesario tener el conocimiento del transito solar, las condiciones atmosfericas, el diseno

  16. Lighting and energy performance for an office using high frequency dimming controls

    International Nuclear Information System (INIS)

    Li, Danny H.W.; Lam, Tony N.T.; Wong, S.L.

    2006-01-01

    Artificial lighting is one of the major electricity consuming items in many non-domestic buildings. Recently, there has been an increasing interest in incorporating daylight in architectural and building designs to reduce the electricity use and enhance greener building developments. This paper presents field measurements for a fully air conditioned open plan office using a photoelectric dimming system. Electric lighting load, indoor illuminance levels and daylight availability were systematically measured and analyzed. The general features and characteristics of the results such as electric lighting energy savings and transmitted daylight illuminance in the forms of frequency distributions and cumulative frequency distributions are presented. Daylighting theories and regression models have been developed and discussed. It has been found that energy savings in electric lighting were over 30% using the high frequency dimming controls. The results from the study would be useful and applicable to other office spaces with similar architectural layouts and daylight linked lighting control systems

  17. Daylighting, Space, and Architecture: A Literature Review

    Directory of Open Access Journals (Sweden)

    Dalia Hafiz

    2015-12-01

    Full Text Available Daylighting dynamism and constant change can characterize buildings and spaces with a living quality that cannot be achieved with any other design element. However, daylighting can create unwanted lighting conditions in the visual field causing discomfort and glare. This may affect the performance of building occupants such as workers or students. Consequently, designing for daylighting needs a good understanding of daylighting. Designers can rely on information from simulation software to re-imagine the space, especially to examine possible unexpected visual discomfort conditions.This paper aims to represent different visual comfort evaluation methods that can help decision-makers make better informed decisions. Different definitions and structures associated with daylight and glare are examined. It also presents a review of the literature of previous research conducted on daylighting, visual comfort analysis and glare studies.

  18. Evaluation of Daylight Intensity for Sustainbility in Residential Buildings in Cantonment Cottages Multan

    Directory of Open Access Journals (Sweden)

    SUMRA YOUSUF

    2017-07-01

    Full Text Available Day lighting is a useful and effective source of energy savings and visual comforts in buildings. Occupants expect good daylight in their living spaces for better living environment. The quality and quantity of natural light entering in to a building depend on both internal and external factors. Daylight strategies basically depend on the accessibility of natural light that is determined by the latitude of the building site and the conditions surrounding the building. Daylight provides lighting energy and energy demand reduction during peak utility hours. Bringing daylight into a building that displaces electric lighting and provides sufficient illumination is the greenest way to light a building presently. This research, aims at analyzing the daylight intensity in residential buildings in Cantonment Cottages Multan which is one of the hottest and progresse city of Pakistan. The intensity of daylight can be expressed in the terms of luminance and daylight factor. In this research, the 5 and 7 marla houses in Cantt Cottages in Multan were selected. The device lux meter was used for measuring intensity with which the brightness appears to the human eye. The readings were taken by placing Lux Meter at the center and near windows in each building component at 2-4 pm. Inorderto evaluate the daylight intensity, the measured luminance in each component of building is compared with the standard illuminance as per recommendation of CIBSE (Chartered Institute of Building Service Engineers. After investigation, it has been found that daylight factor is much higher than the standard values

  19. Daylighting as the Driving Force of the Design Process: from the Results of a Survey to the Implementation into an Advanced Daylighting Project

    Directory of Open Access Journals (Sweden)

    Valerio R.M. Lo Verso

    2014-12-01

    Full Text Available This paper presents a study for the transformation of an industrial area in Turin, Italy. The area hosts two buildings (one of which appointed as listed to be transformed into dwellings. A synergic approach was adopted which combined expertise from architecture, social-economics, psychology and building physics sciences. Building physics sciences lead the research team. A user-centered design was pursued, using a bottom-up approach. A specifically developed questionnaire was submitted on-line to potential users. The survey showed that ‘amount of daylight’, ‘size of rooms’, ‘tranquility of the area’ and ‘presence of a private garden’ were perceived by users to be the most positive aspects of both their present and future, ideal home. These results were then implemented into the project. The exploitation of daylight became the driving force of the transformation project. Especially for the listed building, skylights and light wells were designed to bring daylight into the cores of the buildings, which host common spaces such as libraries or study rooms. The amount of daylight was assessed through the legislative index of the average daylight factor and through a climate-based modeling approach, calculating dynamic metrics such as the spatial daylight autonomy and the Useful Daylight Illuminance. The paper critically compares and discusses these two approaches. Finally, the energy demand for lighting was also calculated to analyze how the increased exploitation of daylight may imply a reduced need for electricity for lighting.

  20. Daylighting and Cooling of Atrium Buildings in Warm Climates: Impact of the Top-Fenestration and Wall Mass Area.

    Science.gov (United States)

    Atif, Morad Rachid

    1992-01-01

    Sun-lighting and daylighting contribute greatly to the aesthetic value of an atrium. However, today's atria are often found either over-lit with extensive cooling loads, or under-lit requiring increased artificial lighting loads. The increase of the top-glazing area increases the cooling loads and decreases the lighting loads. The increase of the mass in the atrium walls decreases the maximum atrium temperature and the cooling loads. Furthermore, the mass distribution and its reflectance affect the lighting levels at the atrium floor. The purpose of this study is to investigate the simultaneous impact of the top-fenestration and the mass and reflectance of atrium walls on the cooling and daylighting performance of atria in warm climates. It attempts to determine the optimum top-fenestration for efficient daylighting and low cooling loads. The daylighting performance was evaluated through illumination measurements in physical models in a sky simulator. The cooling performance was evaluated using the software TRNSYS 13.1. Two types of top-fenestration were tested: horizontal and vertical south-facing, each with three alternate areas. The variations of the atrium walls included materials (standard frame and heavyweight concrete) and percentage and reflectance of the solid area. Two and four-story atria were considered, each with square and linear configuration. The performance was evaluated for three warm climates. The optimum top-fenestration for efficient daylighting was determined. The daylighting prediction algorithm was extended to include the effective reflectance of the atrium walls. The increase of mass in the atrium walls significantly decreased the atrium temperature range, the maximum atrium temperature, and the cooling loads. This impact decreased from horizontal to vertical south-facing top-glazing. The vertical south-facing top-glazing and, to a lesser degree, the reduction of the glazed atrium cover by 50% had more cooling benefits than increasing the

  1. Daylighting Strategies Promote Healthy High Performance Buildings

    Science.gov (United States)

    Gille, Steve

    2010-01-01

    There are many reasons to incorporate daylighting into the building or renovation of K-16 learning facilities. Benefits include increased productivity for students and staff, improved health, a better connection to the outdoors, energy savings and better quality of light. Add the role daylighting can play in LEED certification and it's clear that…

  2. Colour mixing based on daylight

    International Nuclear Information System (INIS)

    Meyn, Jan-Peter

    2008-01-01

    Colour science is based on the sensation of monochromatic light. In contrast to that, surface colours are caused by reflection of wide sections of the daylight spectrum. Non-spectral colours like magenta and purple appear homologous to colours with spectral hue, if the approach of mixing monochromatic light is abandoned. It is shown that a large region of the colour space can be covered by mixing three primary colours derived from lossless spectral decomposition of daylight. These primaries are specified by hue, saturation and luminosity. Duality of additive and subtractive mixing is formulated quantitatively. Experimental demonstrations of calculated results are suggested. This paper is intended for undergraduate optics courses, and advanced interdisciplinary seminars on arts and physics

  3. Performance of a daylight-redirecting glass-shading system

    DEFF Research Database (Denmark)

    Appelfeld, David; Svendsen, Svend

    2013-01-01

    to the original system. The visual comfort was evaluated by glare analysis and the redirected daylight did not cause an additional discomfort glare. The higher utilization of daylight can save 20% of the lighting energy. The thermal insulation of the fenestration was maintained, with slightly increased solar......This paper evaluates the daylighting performance of a prototype external dynamic shading and daylight-redirecting system, and the main focus is on the performance simulation. The demonstration project was carried out on a building with an open-plan office. Part of the original façade was replaced...... with the prototype façade. This layout allowed the use of the same orientation and surroundings for both façades. The working plane illuminance was measured over several months and the measurements were accompanied with annual daylight simulations. The prototype system improved the daylighting conditions compared...

  4. Evaluation of daylight intensity for sustainbility in residential buildings in cantonment cottages multan

    International Nuclear Information System (INIS)

    Yousuf, S.; Maqsood, S.

    2017-01-01

    Day lighting is a useful and effective source of energy savings and visual comforts in buildings. Occupants expect good daylight in their living spaces for better living environment. The quality and quantity of natural light entering in to a building depend on both internal and external factors. Daylight strategies basically depend on the accessibility of natural light that is determined by the latitude of the building site and the conditions surrounding the building. Daylight provides lighting energy and energy demand reduction during peak utility hours. Bringing daylight into a building that displaces electric lighting and provides sufficient illumination is the greenest way to light a building presently. This research, aims at analyzing the daylight intensity in residential buildings in Cantonment Cottages Multan which is one of the hottest and progresse city of Pakistan. The intensity of daylight can be expressed in the terms of luminance and daylight factor. In this research, the 5 and 7 marla houses in Cantt Cottages in Multan were selected. The device lux meter was used for measuring intensity with which the brightness appears to the human eye. The readings were taken by placing Lux Meter at the center and near windows in each building component at 2-4 pm. In order to evaluate the daylight intensity, the measured luminance in each component of building is compared with the standard illuminance as per recommendation of CIBSE (Chartered Institute of Building Service Engineers). After investigation, it has been found that daylight factor is much higher than the standard values as per recommended by CIBSE. The design parameters including building orientation, glazing area, room size to window opening ratio etc. is not appropriate with respect to sustainable design. (author)

  5. Considerations for lighting in the built environment: non-visual effects of light

    Energy Technology Data Exchange (ETDEWEB)

    Webb, A.R. [School of Earth Atmospheric and Environmental Sciences, University of Manchester, Manchester(United Kingdom)

    2006-07-01

    Light is defined as that part of the electromagnetic spectrum (about 380-780 nm) that gives rise to a visual sensation. Lighting in buildings, whether through use of daylight or by artificial means, is designed primarily for the visual needs of the occupants and their expected tasks within a given space. However, solar radiation, and, depending on spectral output of the source, artificial radiation, has other effects on human physiology and behaviour. Blue light affects the circadian rhythm, mood and behaviour; at shorter wavelengths in the ultraviolet (UV) the detriments of photo aging and sunburn are balanced by the benefits of Vitamin D synthesis. (author)

  6. Effects of weather conditions, light conditions, and road lighting on vehicle speed.

    Science.gov (United States)

    Jägerbrand, Annika K; Sjöbergh, Jonas

    2016-01-01

    Light conditions are known to affect the number of vehicle accidents and fatalities but the relationship between light conditions and vehicle speed is not fully understood. This study examined whether vehicle speed on roads is higher in daylight and under road lighting than in darkness, and determined the combined effects of light conditions, posted speed limit and weather conditions on driving speed. The vehicle speed of passenger cars in different light conditions (daylight, twilight, darkness, artificial light) and different weather conditions (clear weather, rain, snow) was determined using traffic and weather data collected on an hourly basis for approximately 2 years (1 September 2012-31 May 2014) at 25 locations in Sweden (17 with road lighting and eight without). In total, the data included almost 60 million vehicle passes. The data were cleaned by removing June, July, and August, which have different traffic patterns than the rest of the year. Only data from the periods 10:00 A.M.-04:00 P.M. and 06:00 P.M.-10:00 P.M. were used, to remove traffic during rush hour and at night. Multivariate adaptive regression splines was used to evaluate the overall influence of independent variables on vehicle speed and nonparametric statistical testing was applied to test for speed differences between dark-daylight, dark-twilight, and twilight-daylight, on roads with and without road lighting. The results show that vehicle speed in general depends on several independent variables. Analyses of vehicle speed and speed differences between daylight, twilight and darkness, with and without road lighting, did not reveal any differences attributable to light conditions. However, vehicle speed decreased due to rain or snow and the decrease was higher on roads without road lighting than on roads with lighting. These results suggest that the strong association between traffic accidents and darkness or low light conditions could be explained by drivers failing to adjust their

  7. Daylight and energy implications for CIE standard skies

    International Nuclear Information System (INIS)

    Li, Danny H.W.

    2007-01-01

    Recently, the International Commission on Illumination (CIE) has adopted a range of 15 standard skies, which include the existing CIE overcast, very clear and cloudless polluted skies, covering the whole probable spectrum of usual skies found in the world. The traditional daylight factor (DF) approach with the calculations being based on an isotropic overcast sky, however, cannot cater to the dynamic variations in daylight luminance and illuminance as the sun's position changes under non-overcast skies. Currently, we propose a numerical procedure that considers the changes in the luminance of sky elements to predict the interior daylight illuminance under the 15 CIE standard skies. This paper evaluates the method by using a typical room with a large vertical glazing window facing north. The available daylight for the room at mean hourly sun positions in each month in terms of DF and illuminance levels were determined and compared with those based on a computer program, namely, RADIANCE. A modification to the ground reflected component was made when a well defined shadow was cast in front of the window facade. It is shown that the results estimated by the proposed approach are in reasonably good agreement with those produced from RADIANCE. The interior daylight and lighting energy consumption were also determined using the proposed and the traditional DF approaches. The findings reveal that daylighting designs using existing CIE overcast sky only would considerably underestimate the indoor daylight availability and electric lighting energy savings, especially under high design indoor illuminance settings

  8. Assessment of daylight quality in simple rooms

    DEFF Research Database (Denmark)

    Johnsen, Kjeld; Dubois, Marie-Claude; Sørensen, Karl Grau

    The present report documents the results of a study on daylight conditions in simple rooms of residential buildings. The overall objective of the study was to develop a basis for a method for the assessment of daylight quality in a room with simple geometry and window configurations. As a tool...... in daylighting conditions for a number of lighting parameters. The results gave clear indications of, for instance, which room would be the brightest, under which conditions might glare be a problem and which type of window would yield the greatest luminous variation (or visual interest), etc....

  9. Evaluation of Daylight Availability for Energy Savings

    Directory of Open Access Journals (Sweden)

    Laura Bellia

    2015-06-01

    Full Text Available Dynamic daylight simulations are very useful instruments in daylighting design process. They allow an in depth analysis of indoor daylight availability levels and define if they are adequate to perform a particular visual task. Their results can be used to design shading devices or lighting control systems and compare different technical solutions. The use of these simulations is likely to spread in the common design practice since some regulations and green building rating systems suggest their use. This paper presents dynamic daylight simulation results related to an open-plan office, performed with Autodesk 3ds Max Design®, which is a calculation software validated by recent researches. It is not used in academic context but it is very widespread between technicians for photorenderings production purposes. The goal of this research is to demonstrate the functionality of this software also in dynamic daylight simulations field and propose an analysis' methodology to use it.

  10. Efficient lighting in buildings: The lack of legislation in Portugal

    International Nuclear Information System (INIS)

    Almeida, António Manuel; Martins, António Gomes

    2014-01-01

    The behavior of building designers is conditioned by the existing legislation and regulations in the national context in which they operate. However, in the Portuguese legislation there are no rules concerning the use of daylight, and therefore, designers are not stimulated to adopt solutions that make use of the existing potential of sunlight availability. In the same way, it is difficult to understand the lack of specific regulation, with quantified targets, limiting power density of artificial lighting installed inside buildings. The present opportunity, generated by the need to carry out the revision of Portuguese building energy systems regulation, should be used to fill the existing gap in national legislation regarding those matters. In this paper the authors present some proposals for future legislation that will have as central purpose the utilization of efficient lighting systems and the promotion of architectural solutions that optimize the use of daylighting. It is possible, and desirable, to add new directives to national legislation that contribute to the improvement of Portuguese buildings, characterized by its good performance in terms of daylight availability, and at the same time, increasing the energy efficiency and reducing the energy consumption of lighting systems installed in those buildings. - Highlights: • In the Portuguese legislation there are no rules concerning the use of daylight. • Lack of specific regulation limiting power density of artificial lighting. • Revision of Portuguese building energy systems regulation. • Some proposals for future legislation. • Improvement of Portuguese buildings promoting energy efficiency

  11. Correlation of classroom typologies to lighting energy performance of academic building in warm-humid climate (case study: ITS Campus Sukolilo Surabaya)

    Science.gov (United States)

    Ekasiwi, S. N. N.; Antaryama, I. G. N.; Krisdianto, J.; Ulum, M. S.

    2018-03-01

    Classrooms in educational buildings require certain lighting requirements to serve teaching and learning activities during daytime. The most typical design is double sided opening in order to get good daylight distribution in the classroom. Using artificial light is essential to contribute the worse daylight condition. A short observation indicates that during the lecture time the light turned on, even in the daytime. That might result in wasting electrical energy. The aim of the study is to examine the type of classroom, which perform comfortable lighting environment as well as saving energy. This paper reports preliminary results of the study obtained from field observation and measurements. The use of energy and usage pattern of artificial lighting during the lecture is recorded and then the data evaluated to see the suitability of existing energy use to building energy standards. The daylighting design aspects have to be the first consideration. However, the similarity in WWR of the classroom, the Daylight Factor (DF) may differ. It depends on the room depth. The similarity of the increase of WWR and Ratio of openings to floor area do not directly correspond to the increase of DF. The outdoor condition of larger daylight access and the room depth are the influencing factors. Despite the similarity of physical type, usage pattern of the classroom imply the use of electrical energy for lighting. The results indicate the factors influencing lighting energy performance in correlation to their typologies

  12. Colour Mixing Based on Daylight

    Science.gov (United States)

    Meyn, Jan-Peter

    2008-01-01

    Colour science is based on the sensation of monochromatic light. In contrast to that, surface colours are caused by reflection of wide sections of the daylight spectrum. Non-spectral colours like magenta and purple appear homologous to colours with spectral hue, if the approach of mixing monochromatic light is abandoned. It is shown that a large…

  13. Engineering a Light-Attenuating Artificial Iris

    Science.gov (United States)

    Shareef, Farah J.; Sun, Shan; Kotecha, Mrignayani; Kassem, Iris; Azar, Dimitri; Cho, Michael

    2016-01-01

    Purpose Discomfort from light exposure leads to photophobia, glare, and poor vision in patients with congenital or trauma-induced iris damage. Commercial artificial iris lenses are static in nature to provide aesthetics without restoring the natural iris's dynamic response to light. A new photo-responsive artificial iris was therefore developed using a photochromic material with self-adaptive light transmission properties and encased in a transparent biocompatible polymer matrix. Methods The implantable artificial iris was designed and engineered using Photopia, a class of photo-responsive materials (termed naphthopyrans) embedded in polyethylene. Photopia was reshaped into annular disks that were spin-coated with polydimethylsiloxane (PDMS) to form our artificial iris lens of controlled thickness. Results Activated by UV and blue light in approximately 5 seconds with complete reversal in less than 1 minute, the artificial iris demonstrates graded attenuation of up to 40% of visible and 60% of UV light. There optical characteristics are suitable to reversibly regulate the incident light intensity. In vitro cell culture experiments showed up to 60% cell death within 10 days of exposure to Photopia, but no significant cell death observed when cultured with the artificial iris with protective encapsulation. Nuclear magnetic resonance spectroscopy confirmed these results as there was no apparent leakage of potentially toxic photochromic material from the ophthalmic device. Conclusions Our artificial iris lens mimics the functionality of the natural iris by attenuating light intensity entering the eye with its rapid reversible change in opacity and thus potentially providing an improved treatment option for patients with iris damage. PMID:27116547

  14. Engineering a Light-Attenuating Artificial Iris.

    Science.gov (United States)

    Shareef, Farah J; Sun, Shan; Kotecha, Mrignayani; Kassem, Iris; Azar, Dimitri; Cho, Michael

    2016-04-01

    Discomfort from light exposure leads to photophobia, glare, and poor vision in patients with congenital or trauma-induced iris damage. Commercial artificial iris lenses are static in nature to provide aesthetics without restoring the natural iris's dynamic response to light. A new photo-responsive artificial iris was therefore developed using a photochromic material with self-adaptive light transmission properties and encased in a transparent biocompatible polymer matrix. The implantable artificial iris was designed and engineered using Photopia, a class of photo-responsive materials (termed naphthopyrans) embedded in polyethylene. Photopia was reshaped into annular disks that were spin-coated with polydimethylsiloxane (PDMS) to form our artificial iris lens of controlled thickness. Activated by UV and blue light in approximately 5 seconds with complete reversal in less than 1 minute, the artificial iris demonstrates graded attenuation of up to 40% of visible and 60% of UV light. There optical characteristics are suitable to reversibly regulate the incident light intensity. In vitro cell culture experiments showed up to 60% cell death within 10 days of exposure to Photopia, but no significant cell death observed when cultured with the artificial iris with protective encapsulation. Nuclear magnetic resonance spectroscopy confirmed these results as there was no apparent leakage of potentially toxic photochromic material from the ophthalmic device. Our artificial iris lens mimics the functionality of the natural iris by attenuating light intensity entering the eye with its rapid reversible change in opacity and thus potentially providing an improved treatment option for patients with iris damage.

  15. Investigation of Architectural Strategies in Relation to Daylight and Integrated Design

    DEFF Research Database (Denmark)

    Jørgensen, Michael; Iversen, Anne; Bjerregaard Jensen, Lotte

    2012-01-01

    his paper investigates the use of daylight in three architecturally successful buildings. The aim is to discuss the challenges and opportunities of architectural daylight strategies in relation to integrated design. All these buildings were designed with the focus on a strategy of using daylight...... to create well-lit, exciting spaces and spatial sequences. The original ideas, thoughts, and decisions behind the designs and daylight strategy are compared with answers in questionnaires from test subjects who have experienced the space and lighting conditions created. The results indicate...... that the architectural daylight strategies formulated by the architects and engineers at the beginning of the design process are actually experienced by the “users” in the existing buildings. The architectural daylight strategy was different in each of the three libraries, and analysis of the results shows that daylight...

  16. THE CASE FOR DAYLIGHTING IN ARCHITECTURE

    Directory of Open Access Journals (Sweden)

    Barrett Richard

    2009-07-01

    Full Text Available The paper discusses the reasons for using daylight in the design of architectural form and space. These reasons extend from those of a practical nature, including energy conservation, cost factors, and health and wellbeing, to those of a more intangible, aesthetic nature. Some historical precedents are offered as examples of projects in which designing to maximize daylighting was crucial in the mind of the architect. By contrast there is also discussion relating to the ‘the lost art’ of using natural lighting in architecture. Some of the reasons for this loss of conviction and expertise are considered. The place of national building codes and other statutory requirements is examined, as is the role of the architect and his/her relationship with other professionals involved in daylighting design in architecture.

  17. Designing with daylight; the relationship between daylight and health

    DEFF Research Database (Denmark)

    Hauge, Bettina

    2015-01-01

    and the significance of daylight. This paper describes the views and significance of daylight to people in their everyday lives. Based on a qualitative research project in Denmark about the use of windows, performed from May to August 2012 among 13 families , using in-depth interviews, observations, photos...... and postcards for storytelling, I will show how daylight is perceived, used, coped with, and negotiated by these people in their homes, thus exploring the social character of a natural phenomenon. A metaphor will be used from biomimetics (Benyus 1997), claiming that the Danish people, like plants, need daylight....... With the concept of ‘dwelling’ (Ingold 2000), which implies that people engage in their environment and create possibilities for dwelling at home to feel comfortable and at home in the world, I illustrate people’s day-to-day entanglements with daylight and highlight the social qualities of daylight. The paper...

  18. Artificial light and nocturnal activity in gammarids

    Directory of Open Access Journals (Sweden)

    Elizabeth K. Perkin

    2014-03-01

    Full Text Available Artificial light is gaining attention as a potential stressor to aquatic ecosystems. Artificial lights located near streams increase light levels experienced by stream invertebrates and we hypothesized light would depress night drift rates. We also hypothesized that the effect of light on drift rates would decrease over time as the invertebrates acclimated to the new light level over the course of one month’s exposure. These hypotheses were tested by placing Gammarus spp. in eight, 75 m × 1 m artificial flumes. One flume was exposed to strong (416 lx artificial light at night. This strong light created a gradient between 4.19 and 0.04 lx over the neighboring six artificial flumes, while a control flume was completely covered with black plastic at night. Night-time light measurements taken in the Berlin area confirm that half the flumes were at light levels experienced by urban aquatic invertebrates. Surprisingly, no light treatment affected gammarid drift rates. In contrast, physical activity measurements of in situ individually caged G. roeseli showed they increased short-term activity levels in nights of complete darkness and decreased activity levels in brightly lit flumes. Both nocturnal and diurnal drift increased, and day drift rates were unexpectadly higher than nocturnal drift.

  19. STRATEGI DAYLIGHTING PADA BANGUNAN MULTI-LANTAI DI ATAS DAN DI BAWAH PERMUKAAN TANAH

    Directory of Open Access Journals (Sweden)

    Danny Santoso Mintorogo

    1999-01-01

    Full Text Available One of the common factor for Energy Saving on buildings has dealed a lot with the lightings on building, especially for multi level floors above and below grade. In order for saving energy on lightings, many daylighting strategies on multi floors building are being used and under-developed by many architects. This paper discusses the strategies of the daylighting techniques on multi floors building both above and below grade Abstract in Bahasa Indonesia : Strategi hemat energi sangat erat hubungan dengan faktor penerangan dalam bangunan, lebih-lebih pada bangunan berlantai banyak diatas atau dibawah permukaan tanah. Untuk menghemat pemakaian energi listrik dari penerangan ini, maka strategi-strategi penerangan alami "Daylighting" terus dikembangkan. Tulisan ini bertujuan memaparkan berbagai strategi daylighting pada bangunan yang berlantai banyak yang dibangun diatas maupun dibawah permukaan tanah. Kata kunci : daylighting, energi

  20. Lightpipe applications for daylighting systems

    NARCIS (Netherlands)

    Rosemann, A.; Kaase, H.

    One of the main research activities of the Institute of Lighting at Technical University of Berlin concerns efficient daylight utilisation in buildings. In recent years, several national and international projects have been and are still carried out. One of them, the European research project

  1. Artificial light pollution increases nocturnal vigilance in peahens.

    Science.gov (United States)

    Yorzinski, Jessica L; Chisholm, Sarah; Byerley, Sydney D; Coy, Jeanee R; Aziz, Aisyah; Wolf, Jamie A; Gnerlich, Amanda C

    2015-01-01

    Artificial light pollution is drastically changing the sensory environments of animals. Even though many animals are now living in these changed environments, the effect light pollution has on animal behavior is poorly understood. We investigated the effect of light pollution on nocturnal vigilance in peahens (Pavo cristatus). Captive peahens were exposed to either artificial lighting or natural lighting at night. We employed a novel method to record their vigilance behavior by attaching accelerometers to their heads and continuously monitoring their large head movements. We found that light pollution significantly increases nocturnal vigilance in peahens. Furthermore, the birds faced a trade-off between vigilance and sleep at night: peahens that were more vigilant spent less time sleeping. Given the choice, peahens preferred to roost away from high levels of artificial lighting but showed no preference for roosting without artificial lighting or with low levels of artificial lighting. Our study demonstrates that light pollution can have a substantial impact on animal behavior that can potentially result in fitness consequences.

  2. Method for including detailed evaluation of daylight levels in Be06

    DEFF Research Database (Denmark)

    Petersen, Steffen

    2008-01-01

    Good daylight conditions in office buildings have become an important issue due to new European regulatory demands which include energy consumption for electrical lighting in the building energy frame. Good daylight conditions in offices are thus in increased focus as an energy conserving measure....... In order to evaluate whether a certain design is good daylight design or not building designers must perform detailed evaluation of daylight levels, including the daylight performance of dynamic solar shadings, and include these in the energy performance evaluation. However, the mandatory national...... calculation tool in Denmark (Be06) for evaluating the energy performance of buildings is currently using a simple representation of available daylight in a room and simple assumptions regarding the control of shading devices. In a case example, this is leading to an overestimation of the energy consumption...

  3. Daylight for energy-saving lamps. Recognizing with lighting sources free of charge; Tageslicht vor Energiesparlampen. Kostenlos verfuegbare Lichtquellen einplanen

    Energy Technology Data Exchange (ETDEWEB)

    David, Holger

    2010-07-01

    With saving energy in the lighting, politics, economics and private households set on compact fluorescent lamps, so called energy-saving lamps. A more economical and pollution free alternative is the increased use of daylight, which is free of charge and felt more pleasant by humans.

  4. Application and Computer Analysis of Solar Systems for the Indoor Daylighting

    International Nuclear Information System (INIS)

    Makhmudov, Is Kandar

    2010-02-01

    A steady increase of energy costs and ever growing environmental concerns in recent years have forced scientists to look for new methods of energy utilization. To resolve these dire problems, the application of renewable energy sources has been considered in various human activities in every sector of society. One of them is the development of solar daylighting systems for residential and commercial buildings, which can improve building energy efficiency and create comfortable indoor environment. Electric lighting represents up to 30 % of building electricity consumption. Therefore, using sunlight in indoor daylighting can significantly reduce electricity consumption in residential and commercial buildings. Moreover, daylight is an important factor in visual environment and improving human well-being. In last decades, different approaches to the design of solar daylighting systems have resulted in various innovative solutions to efficiently introduce natural light in buildings. But their efficiency and cost are still one of primary obstacles in the wider development and distribution of solar daylighting systems. In this study, we investigated the performance of a new solar concentrator system for indoor illumination. The solar concentrator system consists of 30 cm dish concentrators, high precision solar trackers, optical fibers and diffusers for a light distribution. In order to assess the daylighting system's efficiency, there were carried out several experimental measurement series. One of them was an application of our solar daylighting system to two standard classrooms with south- and north-oriented windows in Jeju city, Korea. At the same time classrooms were modeled by using ECOTECT and exported to RADIANCE for daylighting simulations. Results from the measurements and simulations were analyzed comprehensively to establish the reliability of the modeling process. Following this, we modeled both classrooms with the above mentioned daylighting systems

  5. Application and Computer Analysis of Solar Systems for the Indoor Daylighting

    Energy Technology Data Exchange (ETDEWEB)

    Makhmudov, Is Kandar

    2010-02-15

    A steady increase of energy costs and ever growing environmental concerns in recent years have forced scientists to look for new methods of energy utilization. To resolve these dire problems, the application of renewable energy sources has been considered in various human activities in every sector of society. One of them is the development of solar daylighting systems for residential and commercial buildings, which can improve building energy efficiency and create comfortable indoor environment. Electric lighting represents up to 30 % of building electricity consumption. Therefore, using sunlight in indoor daylighting can significantly reduce electricity consumption in residential and commercial buildings. Moreover, daylight is an important factor in visual environment and improving human well-being. In last decades, different approaches to the design of solar daylighting systems have resulted in various innovative solutions to efficiently introduce natural light in buildings. But their efficiency and cost are still one of primary obstacles in the wider development and distribution of solar daylighting systems. In this study, we investigated the performance of a new solar concentrator system for indoor illumination. The solar concentrator system consists of 30 cm dish concentrators, high precision solar trackers, optical fibers and diffusers for a light distribution. In order to assess the daylighting system's efficiency, there were carried out several experimental measurement series. One of them was an application of our solar daylighting system to two standard classrooms with south- and north-oriented windows in Jeju city, Korea. At the same time classrooms were modeled by using ECOTECT and exported to RADIANCE for daylighting simulations. Results from the measurements and simulations were analyzed comprehensively to establish the reliability of the modeling process. Following this, we modeled both classrooms with the above mentioned daylighting systems

  6. Could Daylight Glare Be Defined Mathematically?Results of Testing the DGIN Method in Japan

    Science.gov (United States)

    Nazzal, Ali; Oki, Masato

    Discomfort glare from daylight is a common problem without valid prediction methods so far. A new mathematical DGIN (New Daylight Glare Index) method tries to respond the challenge. This paper reports on experiments carried out in daylit office environment in Japan to test applicability of the method. Slight positive correlation was found between the DGIN and the subjective evaluation. Additionally, a high Ladaptation value together with the small ratio of Lwindow to Ladaptation was obviously experienced sufficient to neutralize the effect of glare discomfort. However, subjective assessments are poor glare indicators and not reliable in testing glare prediction methods. DGIN is a good indicator of daylight glare, and when the DGIN value is analyzed together with the measured illuminance ratios, discomfort glare from daylight can be analyzed in a quantitative manner. The DGIN method could serve architects and lighting designers in testing daylighting systems, and also guide the action of daylight responsive lighting controls.

  7. Artificial light pollution increases nocturnal vigilance in peahens

    Directory of Open Access Journals (Sweden)

    Jessica L. Yorzinski

    2015-08-01

    Full Text Available Artificial light pollution is drastically changing the sensory environments of animals. Even though many animals are now living in these changed environments, the effect light pollution has on animal behavior is poorly understood. We investigated the effect of light pollution on nocturnal vigilance in peahens (Pavo cristatus. Captive peahens were exposed to either artificial lighting or natural lighting at night. We employed a novel method to record their vigilance behavior by attaching accelerometers to their heads and continuously monitoring their large head movements. We found that light pollution significantly increases nocturnal vigilance in peahens. Furthermore, the birds faced a trade-off between vigilance and sleep at night: peahens that were more vigilant spent less time sleeping. Given the choice, peahens preferred to roost away from high levels of artificial lighting but showed no preference for roosting without artificial lighting or with low levels of artificial lighting. Our study demonstrates that light pollution can have a substantial impact on animal behavior that can potentially result in fitness consequences.

  8. Daylighting performance evaluation of a bottom-up motorized roller shade

    Energy Technology Data Exchange (ETDEWEB)

    Kapsis, K.; Athienitis, A.K.; Zmeureanu, R.G. [Department of Building, Civil and Environmental Engineering, Concordia University, Montreal, QC (Canada); Tzempelikos, A. [School of Civil Engineering, Purdue University, West Lafayette, IN (United States)

    2010-12-15

    This paper presents an experimental and simulation study for quantifying the daylighting performance of bottom-up roller shades installed in office spaces. The bottom-up shade is a motorized roller shade that opens from top to bottom operating in the opposite direction of a conventional roller shade, so as to cover the bottom part of the window, while allowing daylight to enter from the top part of the window, reaching deeper into the room. A daylighting simulation model, validated with full-scale experiments, was developed in order to establish correlations between the shade position, outdoor illuminance and work plane illuminance for different outdoor conditions. Then, a shading control algorithm was developed for application in any location and orientation. The validated model was employed for a sensitivity analysis of the impact of shade optical properties and control on the potential energy savings due to the use of daylighting. The results showed that Daylight Autonomy for the bottom-up shade is 8-58% higher compared to a conventional roller shade, with a difference of 46% further away from the facade, where the use of electric lighting is needed most of the time. The potential reduction in energy consumption for lighting is 21-41%. (author)

  9. Penguin colony attendance under artificial lights for ecotourism.

    Science.gov (United States)

    Rodríguez, Airam; Holmberg, Ross; Dann, Peter; Chiaradia, André

    2018-03-30

    Wildlife watching is an emerging ecotourism activity around the world. In Australia and New Zealand, night viewing of little penguins attracts hundreds of thousands of visitors per year. As penguins start coming ashore after sunset, artificial lighting is essential to allow visitors to view them in the dark. This alteration of the nightscape warrants investigation for any potential effects of artificial lighting on penguin behavior. We experimentally tested how penguins respond to different light wavelengths (colors) and intensities to examine effects on the colony attendance behavior at two sites on Phillip Island, Australia. At one site, nocturnal artificial illumination has been used for penguin viewing for decades, whereas at the other site, the only light is from the natural night sky. Light intensity did not affect colony attendance behaviors of penguins at the artificially lit site, probably due to penguin habituation to lights. At the not previously lit site, penguins preferred lit paths over dark paths to reach their nests. Thus, artificial light might enhance penguin vision at night and consequently it might reduce predation risk and energetic costs of locomotion through obstacle and path detection. Although penguins are faithful to their path, they can be drawn to artificial lights at small spatial scale, so light pollution could attract penguins to undesirable lit areas. When artificial lighting is required, we recommend keeping lighting as dim and time-restricted as possible to mitigate any negative effects on the behavior of penguins and their natural habitat. © 2018 Wiley Periodicals, Inc.

  10. Rethinking daylighting and compliance

    Directory of Open Access Journals (Sweden)

    John Mardaljevic

    2013-10-01

    Full Text Available Daylight in buildings is the natural illumination experienced by the occupants of any man-made construction with openings to the outside. Our attempts to formulate some measure of daylight provision in buildings can be traced back over a century, and the daylight factor as we know it today is over 50 years old. Still the most common measure found in guidelines and recommendations worldwide, the daylight factor is used routinely and, it is fair to say, often rather uncritically. The consideration of daylight in buildings has received a new impetus from the accumulation of evidence on the wider benefits of daylight exposure. But it is continuing to prove difficult to advance beyond daylight factors towards a more realistic quantification of daylighting performance that would allow us to accommodate these new considerations in an evaluative schema. This paper examines the basis of current practice with respect to daylight evaluation, and suggests a few ways in which it can be improved with relatively modest additional effort. The paper also critiques some of the recent attempts to advance daylight evaluation by incremental means using so-called “clear sky options”.

  11. Impact of three window configurations on daylight conditions

    DEFF Research Database (Denmark)

    Dubois, Marie-Claude; Sørensen, Karl Grau; Traberg-Borup, Steen

    The report describes the results of a pilot study on daylight conditions in simple rooms of residential buildings. As a tool for the analyses the Radiance Lighting Simulating System was used to simulate one room with three different window configurations, a vertical window, a dormer window......, and a roof window. The simulations were performed for overcast sky conditions and under one sunny sky, for two different times of the day. The study shows that the window configuration affects the daylight conditions (distribution and intensity) significantly. The roof window results in a higher (average......) daylight factor on a horizontal plane, i.e. more than twice as high compared with the vertical window, and more than triple as high compared with the dormer window....

  12. NOUR. Daylighting and thermal effects of windows in desert houses

    Energy Technology Data Exchange (ETDEWEB)

    Ouahrani, Djamel

    1999-07-01

    This study is on a combined effect of window, the daylighting and the thermal effects, in desert houses. It is comprised of two complementary studies. In the introduction a historical review on the development of using daylight has been carried out in order to place the case study in a historical perspective. The first study is comprehensive and contains two main parts. In the first part a study was carried out on the people and history of the town of Ghardaia in Southern Algeria. This was done in order to understand the architectural form of that region. The second part is experimental and consists of two field studies carried out in Ghardaia. Their aim was to investigate the influence of daylight and temperature on the use of residential houses. This investigation included both traditional and 'modern' houses, the modern having relatively large windows similar to those of the northern part of Algeria, the traditional ones having small or no windows. The second study is also experimental consisting of computer parametric studies on window design from two standpoints, namely daylighting level and thermal effects of windows in desert houses. A typical traditional house is described as it was observed. Then the recorded light values are presented and commented upon. In the second part, three types of modern houses observed in the field studies are presented and compared to the traditional archetype. The comparison especially dwells on the relative effectiveness of the two systems of daylighting. In the third part, focusing on various issues of lighting, the results of interviews with the inhabitants are presented. The historical studies indicate that the process of housing development, in several respects, has reached a certain quality (social, technology, and adaptation to climate) appropriate to the local original context, but that development has slowed down. The results of the lighting study indicate that the use of more windows in modern houses

  13. NOUR. Daylighting and thermal effects of windows in desert houses

    Energy Technology Data Exchange (ETDEWEB)

    Ouahrani, Djamel

    1999-07-01

    This study is on a combined effect of window, the daylighting and the thermal effects, in desert houses. It is comprised of two complementary studies. In the introduction a historical review on the development of using daylight has been carried out in order to place the case study in a historical perspective. The first study is comprehensive and contains two main parts. In the first part a study was carried out on the people and history of the town of Ghardaia in Southern Algeria. This was done in order to understand the architectural form of that region. The second part is experimental and consists of two field studies carried out in Ghardaia. Their aim was to investigate the influence of daylight and temperature on the use of residential houses. This investigation included both traditional and 'modern' houses, the modern having relatively large windows similar to those of the northern part of Algeria, the traditional ones having small or no windows. The second study is also experimental consisting of computer parametric studies on window design from two standpoints, namely daylighting level and thermal effects of windows in desert houses. A typical traditional house is described as it was observed. Then the recorded light values are presented and commented upon. In the second part, three types of modern houses observed in the field studies are presented and compared to the traditional archetype. The comparison especially dwells on the relative effectiveness of the two systems of daylighting. In the third part, focusing on various issues of lighting, the results of interviews with the inhabitants are presented. The historical studies indicate that the process of housing development, in several respects, has reached a certain quality (social, technology, and adaptation to climate) appropriate to the local original context, but that development has slowed down. The results of the lighting study indicate that the use of more windows in modern houses constitutes a

  14. The impact of windows and daylight on acute-care nurses' physiological, psychological, and behavioral health.

    Science.gov (United States)

    Zadeh, Rana Sagha; Shepley, Mardelle McCuskey; Williams, Gary; Chung, Susan Sung Eun

    2014-01-01

    To investigate the physiological and psychological effects of windows and daylight on registered nurses. To date, evidence has indicated that appropriate environmental lighting with characteristics similar to natural light can improve mood, alertness, and performance. The restorative effects of windows also have been documented. Hospital workspaces generally lack windows and daylight, and the impact of the lack of windows and daylight on healthcare employees' well being has not been thoroughly investigated. Data were collected using multiple methods with a quasi-experimental approach (i.e., biological measurements, behavioral mapping, and analysis of archival data) in an acute-care nursing unit with two wards that have similar environmental and organizational conditions, and similar patient populations and acuity, but different availability of windows in the nursing stations. Findings indicated that blood pressure (p windows and daylight. A possible micro-restorative effect of windows and daylight may result in lowered blood pressure and increased oxygen saturation and a positive effect on circadian rhythms (as suggested by body temperature) and morning sleepiness. Critical care/intensive care, lighting, nursing, quality care, work environment.

  15. Design and evaluation of daylighting applications of holographic glazings

    Energy Technology Data Exchange (ETDEWEB)

    Papamichael, K.; Ehrlich, C.; Ward, G.

    1996-12-01

    According to the contractual agreement, BTP would develop a computer model of the POC holographic structures and then simulate the performance of alternative designs using the RADIANCE lighting and rendering computer program [Ward 1990]. The RADIANCE model would then be used to evaluate the daylight performance of alternative designs of holographic glazings in a prototypical office space. The simulation process would be validated against actual photometric measurements of holographic glazing samples developed by POC. The results would be used to evaluate the potential for increased electric lighting savings through increased daylight illuminance levels at distances more than 15 ft--20 ft (4.6 m--6.1 m ) from the window wall.

  16. Hardware-in-the-Loop Modeling and Simulation Methods for Daylight Systems in Buildings

    Science.gov (United States)

    Mead, Alex Robert

    This dissertation introduces hardware-in-the-loop modeling and simulation techniques to the daylighting community, with specific application to complex fenestration systems. No such application of this class of techniques, optimally combining mathematical-modeling and physical-modeling experimentation, is known to the author previously in the literature. Daylighting systems in buildings have a large impact on both the energy usage of a building as well as the occupant experience within a space. As such, a renewed interest has been placed on designing and constructing buildings with an emphasis on daylighting in recent times as part of the "green movement.''. Within daylighting systems, a specific subclass of building envelope is receiving much attention: complex fenestration systems (CFSs). CFSs are unique as compared to regular fenestration systems (e.g. glazing) in the regard that they allow for non-specular transmission of daylight into a space. This non-specular nature can be leveraged by designers to "optimize'' the times of the day and the days of the year that daylight enters a space. Examples of CFSs include: Venetian blinds, woven fabric shades, and prismatic window coatings. In order to leverage the non-specular transmission properties of CFSs, however, engineering analysis techniques capable of faithfully representing the physics of these systems are needed. Traditionally, the analysis techniques available to the daylighting community fall broadly into three classes: simplified techniques, mathematical-modeling and simulation, and physical-modeling and experimentation. Simplified techniques use "rules-of-thumb'' heuristics to provide insights for simple daylighting systems. Mathematical-modeling and simulation use complex numerical models to provide more detailed insights into system performance. Finally, physical-models can be instrumented and excited using artificial and natural light sources to provide performance insight into a daylighting system

  17. Delight2 Daylighting Analysis in Energy Plus: Integration and Preliminary User Results

    Energy Technology Data Exchange (ETDEWEB)

    Carroll, William L.; Hitchcock, Robert J.

    2005-04-26

    DElight is a simulation engine for daylight and electric lighting system analysis in buildings. DElight calculates interior illuminance levels from daylight, and the subsequent contribution required from electric lighting to meet a desired interior illuminance. DElight has been specifically designed to integrate with building thermal simulation tools. This paper updates the DElight capability set, the status of integration into the simulation tool EnergyPlus, and describes a sample analysis of a simple model from the user perspective.

  18. Daylight-mediated photodynamic therapy of moderate to thick actinic keratoses of the face and scalp

    DEFF Research Database (Denmark)

    Wiegell, S.R.; Fabricius, S.; Philipsen, P.A.

    2012-01-01

    response rate and light dose in patients who received an effective light dose of > 3·5 J cm . Conclusions: Daylight-mediated PDT of moderate to thick AKs was less effective than daylight-mediated PDT of thin AKs especially in some centres. However, nearly all thicker lesions (grades II and III) were...

  19. The role of fenestration in promoting daylight performance. The mosques of Alexandria since the 19th century

    Directory of Open Access Journals (Sweden)

    Ingy I. El-Darwish

    2016-12-01

    Full Text Available Mosques have always been sacred places with distinctive sustainable environments. Fenestration in the prayers’ zone whether clerestories, screened windows, dome lighting and other light features have managed to produce significant spiritual human comfort areas. This paper focuses on fenestration of divine mosques and relates them to promoting daylight performance. The research process emphasizes the importance of daylight performance by promoting simulation tools on historical mosques of Alexandria since the 19th century that has witnessed change over time. The paper is a step toward sustainable lighting schemes in prayers’ zones that help to achieve human comfort as well as minimize use of energy. This study aimed at investigating the daylight performance by the use of climate based daylighting metrics which is “Daylight Autonomy” (DA. Daylight Autonomy is evaluated in the year round for the day lighted prayer periods to evaluate the behavior of fenestration of the different selected sample of mosques since the 19th century in Alexandria on a simulation tool in order to check whether it complies with the required illuminate and glare levels. The research findings are an attempt to lead to performative design guidelines introducing a contemporary interpretation for use in enhancing new designs of these holistic buildings.

  20. Daylight calculations in practice

    DEFF Research Database (Denmark)

    Iversen, Anne; Roy, Nicolas; Hvass, Mette

    The aim of the project was to obtain a better understanding of what daylight calculations show and also to gain knowledge of how the different daylight simulation programs perform compared with each other. Experience has shown that results for the same room, obtained from two daylight simulation...... programs can give different results. This can be due to restrictions in the program itself and/or be due to the skills of the persons setting up the models. This is crucial as daylight calculations are used to document that the demands and recommendations to daylight levels outlined by building authorities....... The aim of the project was to obtain a better understanding of what daylight calculations show and also to gain knowledge of how the different daylight simulation programs perform compared with each other. Furthermore the aim was to provide knowledge of how to build up the 3D models that were...

  1. Study of effect of daylight on Building User's Performance Based on Electroencephalograph Signal

    NARCIS (Netherlands)

    Mangkuto, R.A.; Soelami, F.X.N.; Suprijanto, S.

    2009-01-01

    The use of daylighting in building nowadays has become one alternative to save electric energy consumption, particularly during daytime. Daylight is not only useful for reducing cost from electric light sources, but also give benefits both physiologically and psychologically for building users.

  2. Biological Effects Of Artificial Illumination

    Science.gov (United States)

    Corth, Richard

    1980-10-01

    We are increasingly being warned of the possible effects of so called "polluted" light, that is light that differs in spectral content from that of sunlight. We should be concerned, we are told, because all animals and plants have evolved under this natural daylight and therefore any difference between that illuminant and the artificial illuminants that are on the market today, is suspect. The usual presentation of the differences between the sunlight and the artificial illuminants are as shown in Figure 1. Here we are shown the spectral power distribution of sunlight and Cool White fluorescent light. The spectral power distributions of each have been normalized to some convenient wavelength so that each can be seen and easily compared on the same figure. But this presentation is misleading for one does not experience artificial illuminants at the same intensity as one experiences sunlight. Sunlight intensities are ordinarily found to be in the 8000 to 10,000 footcandle range whereas artificial illuminants are rarely experienced at intensity levels greater than 100 footcandles. Therefore a representative difference between the two types of illumination conditions is more accurately represented as in Figure 2. Thus if evolutionary adaptations require that humans and other animals be exposed to sunlight to ensure wellbeing, it is clear that one must be exposed to sunlight intensities. It is not feasible to expect that artificially illuminated environments will be lit to the same intensity as sunlight

  3. Characterization of hybrid lighting systems of the Electrical Engineering Building in the Industrial University of Santander

    Science.gov (United States)

    Galvis, D.; Exposito, C.; Osma, G.; Amado, L.; Ordóñez, G.

    2016-07-01

    This paper presents an analysis of hybrid lighting systems of Electrical Engineering Building in the Industrial University of Santander, which is a pilot of green building for warm- tropical conditions. Analysis of lighting performance of inner spaces is based on lighting curves obtained from characterization of daylighting systems of these spaces. A computation tool was made in Excel-Visual Basic to simulate the behaviour of artificial lighting system considering artificial control system, user behaviour and solar condition. Also, this tool allows to estimate the electrical energy consumption of the lighting system for a day, a month and a year.

  4. Lives under the Sun; The sensory qualities of daylight in designing the everyday

    DEFF Research Database (Denmark)

    Hauge, Bettina

    2015-01-01

    People’s sensations of daylight and their practical, daily engagements with the sun and the daylight are described in this article. Based on a qualitative research project in Denmark the article shows how some Danes experience the world through the sun and its daylight and illustrates its...... significance to their bodies and lives as they describe it. By taking a biomimetic approach a metaphor is presented that, like plants, some people crave daylight in order to feel well. By showing people’s engagement with the sun and its daylight the phenomenon of natural light becomes imbued with sociality...... and it is described how people design their everyday in accordance with the sun. The sensation of daylight normally taken for granted and acknowledged as a physiological element in our being-in-the-world is foregrounded and shown as a sense in people that may have a physiological origin when daylight hits the eye...

  5. Daylighting System Based on Novel Design of Linear Fresnel lens

    Directory of Open Access Journals (Sweden)

    Thanh Tuan Pham

    2017-10-01

    Full Text Available In this paper, we present a design and optical simulation of a daylighting system using a novel design of linear Fresnel lens, which is constructed based on the conservation of optical path length and edge ray theorem. The linear Fresnel lens can achieve a high uniformity by using a new idea of design in which each groove of the lens distributes sunlight uniformly over the receiver so that the whole lens also uniformly distributes sunlight over the receiver. In this daylighting system, the novel design of linear Fresnel lens significantly improves the uniformity of collector and distributor. Therefore, it can help to improve the performance of the daylighting system. The structure of the linear Fresnel lenses is designed by using Matlab. Then, the structure of lenses is appreciated by ray tracing in LightToolsTM to find out the optimum lens shape. In addition, the simulation is performed by using LightToolsTM to estimate the efficiency of the daylighting system. The results show that the designed collector can achieve the efficiency of ~80% with the tolerance of ~0.60 and the concentration ratio of 340 times, while the designed distributor can reach a high uniformity of >90%.

  6. Experimental study on modelling and control of lighting components in a test-cell building

    NARCIS (Netherlands)

    Yahiaoui, Azzedine

    2018-01-01

    The perfect control of shading devices, particularly venetian blinds can significantly improve the rational use of daylight in buildings and provide enhanced visual comfort for occupants while saving the electricity that would be used for artificial lighting. This study proposes a control strategy

  7. Artificial light and quantum order in systems of screened dipoles

    International Nuclear Information System (INIS)

    Wen Xiaogang

    2003-01-01

    The origin of light is an unsolved mystery in nature. Recently, it was suggested that light may originate from a new kind of order, quantum order. To test this idea in experiments, we study systems of screened magnetic/electric dipoles in two-dimensional (2D) and 3D lattices. We show that our models contain an artificial light-a photonlike collective excitation. We discuss how to design realistic devices that realize our models. We show that the 'speed of light' and the 'fine-structure constant' of the artificial light can be tuned in our models. The properties of artificial atoms (bound states of pairs of artificial charges) are also discussed. The existence of artificial light (as well as artificial electron) in condensed-matter systems suggests that elementary particles, such as light and electron, may not be elementary. They may be collective excitations of quantum order in our vacuum. In our model, light is realized as a fluctuation of string-nets and charges as the ends of open strings (or nodes of string nets)

  8. Artificial light alters natural regimes of night-time sky brightness

    Science.gov (United States)

    Davies, Thomas W.; Bennie, Jonathan; Inger, Richard; Gaston, Kevin J.

    2013-01-01

    Artificial light is globally one of the most widely distributed forms of anthropogenic pollution. However, while both the nature and ecological effects of direct artificial lighting are increasingly well documented, those of artificial sky glow have received little attention. We investigated how city lights alter natural regimes of lunar sky brightness using a novel ten month time series of measurements recorded across a gradient of increasing light pollution. In the city, artificial lights increased sky brightness to levels six times above those recorded in rural locations, nine and twenty kilometers away. Artificial lighting masked natural monthly and seasonal regimes of lunar sky brightness in the city, and increased the number and annual regime of full moon equivalent hours available to organisms during the night. The changes have potentially profound ecological consequences.

  9. Daylight Management in Mediterranean Cities: When Shortage Is Not the Issue

    Directory of Open Access Journals (Sweden)

    Judit Lopez-Besora

    2016-09-01

    Full Text Available Natural resources such as daylight and sunlight are highly appreciated in countries with prevailing overcast skies. Taking advantage of this scarce resource contributes to saving energy on artificial lighting. In contrast to northern, southern European cities are distinguished by a large number of days with direct sunlight caused by a propitious climate condition. While it is a positive issue in terms of energy availability, the abundance of it can be counterproductive if management measures are not taken. Apart from the thermal consequences, lighting penetration into buildings causes a great contrast between inside and outside. This is especially critical when the visual system does not have enough time to adapt, as happens at entrance areas. The aim of this study is to analyze the light contrast between these areas and the urban outside in sunny conditions. To attain this objective, light data from five entrance spaces and their contiguous streets were analyzed and measured. The results were divided into three zones in the visual scene, showing an increasing contrast from top to bottom of the visual field. It may be concluded that interventions applied to urban areas and building pavements can improve visual adaptation in the transition zone.

  10. USE OF ARTIFICIAL LIGHT IN MUSHROOM CULTIVATION

    Directory of Open Access Journals (Sweden)

    N. L. Poyedinok

    2013-12-01

    Full Text Available Artificial light is used in greenhouses to increase productivity and quality of agricultural and ornamental plants. Despite the awareness of the fact that light also plays important role in the life of nonhotosynthetic organisms, such as fungi, its using in their biotechnology cultivation is currently limited. Science has quite a large amount information about the influence of artificial light of different nature on morphogenesis, metabolic processes and productivity of more than 100 species of fungi, many of which are valuable producers of biologically active compounds. Themechanisms of photoreactions of various fungi, which is an integral part of a purposeful photoregulation their activity in biotechnological processes are described. The analysis of the researches and of the experience of their practical application allows predicting potential of using artificial light in mushroom growing industry, as well as in creating highly productive, environmentally clean technologies of targeted synthesis of the final product.

  11. Effect of daylight saving time on lighting energy use: A literature review

    International Nuclear Information System (INIS)

    Aries, Myriam B.C.; Newsham, Guy R.

    2008-01-01

    The principal reason for introducing (and extending) daylight saving time (DST) was, and still is, projected energy savings, particularly for electric lighting. This paper presents a literature review concerning the effects of DST on energy use. Simple estimates suggest a reduction in national electricity use of around 0.5%, as a result of residential lighting reduction. Several studies have demonstrated effects of this size based on more complex simulations or on measured data. However, there are just as many studies that suggest no effect, and some studies suggest overall energy penalties, particularly if gasoline consumption is accounted for. There is general consensus that DST does contribute to an evening reduction in peak demand for electricity, though this may be offset by an increase in the morning. Nevertheless, the basic patterns of energy use, and the energy efficiency of buildings and equipment have changed since many of these studies were conducted. Therefore, we recommend that future energy policy decisions regarding changes to DST be preceded by high-quality research based on detailed analysis of prevailing energy use, and behaviours and systems that affect energy use. This would be timely, given the extension to DST underway in North America in 2007

  12. Development of Optical Fiber-Based Daylighting System and Its Comparison

    Directory of Open Access Journals (Sweden)

    Irfan Ullah

    2015-07-01

    Full Text Available Fiber-optic daylighting systems have been shown to be a promising and effective way to transmit sunlight in the interior space whilst reducing electric lighting energy consumption. To increase efficiency in terms of providing uniform illumination in the interior, the current need is to illuminate optical fiber-bundle with uniform light flux. To this end, we propose a method for achieving collimated light, which illuminates the fiber-bundle uniformly. Light is collected through a parabolic concentrator and focused toward a collimating lens, which distributes the light over each optical fiber. An optics diffusing structure is utilized at the end side of the fiber bundle to spread light in the interior. The results clearly reveal that the efficiency in terms of uniform illumination, which also reduces the heat problem for optical fibers, is improved. Furthermore, a comparison study is conducted between current and previous approaches. As a result, the proposed daylighting system turns out convenient in terms of energy saving and reduction in greenhouse gas emissions.

  13. Optimal sun-shading design for enhanced daylight illumination of subtropical classrooms

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Ming-Chin [Architecture and Building Research Institute, MOI (China); Chiang, Che-Ming [Department of Architecture, National Cheng-Kung University, Tainan 701 (China); Chou, Po-Cheng [Department of Interior Design, Shu-Te University, No. 59 Hun-Shan Road, Yenchau 82445, Kaohsiung County (China); Chang, Kuei-Feng [Department of Real Estate Management, National Pingtung Institute of Commerce (China); Lee, Chia-Yen [Department of Mechanical and Automation Engineering, Da-Yeh University, Changhua 515 (China)

    2008-07-01

    This study investigates the feasibility of fitting windows with sun-shadings in order to minimize the lighting power costs in daylight-illuminated classrooms lit from a single side in subtropical regions. An IES-CPC model is created of a representative classroom in Taiwan, and a series of simulations is performed to determine the average illuminance value and the uniformity of the illuminance distribution in the classroom under various lighting conditions with no sun-shadings fitted to the window. The numerical results are found to be in good agreement with the experimental measurements obtained using an array of nine-channel photometers. Having confirmed the validity of the simulation scheme, the illumination properties of four different sun-shading designs are considered. The results show that a double-layered sun-shading represents the optimal sun-shading design in terms of achieving a uniform illumination distribution within the classroom. Given appropriate physical dimensions, this daylight access device achieves the minimum illuminance requirement of 500 lx and improves the lighting uniformity ratio from 0.25-0.35 to 0.40-0.42. Furthermore, using this sun-shading device, the required illuminance ratio of 0.5 can be obtained simply by switching on one of the three rows of lights in the classroom. Accordingly, the daylight access device not only improves the illuminance conditions within the classroom, but also reduces the lighting power cost by 71.5% compared to the case where all of the lights are turned on. (author)

  14. Migratory bats respond to artificial green light with positive phototaxis.

    Directory of Open Access Journals (Sweden)

    Christian C Voigt

    Full Text Available Artificial light at night is spreading worldwide at unprecedented rates, exposing strictly nocturnal animals such as bats to a novel anthropogenic stressor. Previous studies about the effect of artificial light on bats focused almost exclusively on non-migratory species, yet migratory animals such as birds are known to be largely affected by light pollution. Thus, we conducted a field experiment to evaluate if bat migration is affected by artificial light at night. In late summer, we presented artificial green light of 520 nm wavelength to bats that were migrating south along the shoreline of the Baltic Sea. Using a light on-off treatment, we observed that the activity of Pipistrellus nathusii and P. pygmaeus, the two most abundant migratory species at our site, increased by more than 50% in the light-on compared to the light-off treatment. We observed an increased number of feeding buzzes during the light-on compared to the light-off treatment for P. nathusii. However, feeding activity was low in general and did not increase disproportionately during the light-on treatment in relation to the overall echolocation call activity of bats. Further, P. nathusii were attracted towards the green light at a distance of about 23 m, which is way beyond the echolocation detection range for insects of Nathusius' bats. We therefore infer that migratory bats were not attracted to artificial green light because of high insect densities, but instead by positive phototaxis. We conclude that artificial light at night may potentially impact bat migration in a yet unrecognized way.

  15. Quantifying the radiant exposure and effective dose in patients treated for actinic keratoses with topical photodynamic therapy using daylight and LED white light

    Science.gov (United States)

    Manley, M.; Collins, P.; Gray, L.; O'Gorman, S.; McCavana, J.

    2018-02-01

    Daylight photodynamic therapy (dl-PDT) is as effective as conventional PDT (c-PDT) for treating actinic keratoses but has the advantage of reducing patient discomfort significantly. Topical dl-PDT and white light-PDT (wl-PDT) differ from c-PDT by way of light sources and methodology. We measured the variables associated with light dose delivery to skin surface and influence of geometry using a radiometer, a spectral radiometer and an illuminance meter. The associated errors of the measurement methods were assessed. The spectral and spatial distribution of the radiant energy from the LED white light source was evaluated in order to define the maximum treatment area, setup and treatment protocol for wl-PDT. We compared the data with two red LED light sources we use for c-PDT. The calculated effective light dose is the product of the normalised absorption spectrum of the photosensitizer, protoporphyrin IX (PpIX), the irradiance spectrum and the treatment time. The effective light dose from daylight ranged from 3  ±  0.4 to 44  ±  6 J cm-2due to varying weather conditions. The effective light dose for wl-PDT was reproducible for treatments but it varied across the treatment area between 4  ±  0.1 J cm-2 at the edge and 9  ±  0.1 J cm-2 centrally. The effective light dose for the red waveband (615-645 nm) was 0.42  ±  0.05 J cm-2 on a clear day, 0.05  ±  0.01 J cm-2 on an overcast day and 0.9  ±  0.01 J cm-2 using the white light. This compares with 0.95  ±  0.01 and 0.84  ±  0.01 J cm-2 for c-PDT devices. Estimated errors associated with indirect determination of daylight effective light dose were very significant, particularly for effective light doses less than 5 J cm-2 (up to 83% for irradiance calculations). The primary source of error is in establishment of the relationship between irradiance or illuminance and effective dose. Use of the O’Mahoney model is recommended using a

  16. Out of the Lab and into the Bathroom: Evening Short-Term Exposure to Conventional Light Suppresses Melatonin and Increases Alertness Perception

    Directory of Open Access Journals (Sweden)

    Heinz Schoepp

    2013-01-01

    Full Text Available Life in 24-h society relies on the use of artificial light at night that might disrupt synchronization of the endogenous circadian timing system to the solar day. This could have a negative impact on sleep–wake patterns and psychiatric symptoms. The aim of the study was to investigate the influence of evening light emitted by domestic and work place lamps in a naturalistic setting on melatonin levels and alertness in humans. Healthy subjects (6 male, 3 female, 22–33 years were exposed to constant dim light (<10 lx for six evenings from 7:00 p.m. to midnight. On evenings 2 through 6, 1 h before habitual bedtime, they were also exposed to light emitted by 5 different conventional lamps for 30 min. Exposure to yellow light did not alter the increase of melatonin in saliva compared to dim light baseline during (38 ± 27 pg/mL vs. 39 ± 23 pg/mL and after light exposure (39 ± 22 pg/mL vs. 44 ± 26 pg/mL. In contrast, lighting conditions including blue components reduced melatonin increase significantly both during (office daylight white: 25 ± 16 pg/mL, bathroom daylight white: 24 ± 10 pg/mL, Planon warm white: 26 ± 14 pg/mL, hall daylight white: 22 ± 14 pg/mL and after light exposure (office daylight white: 25 ± 15 pg/mL, bathroom daylight white: 23 ± 9 pg/mL, Planon warm white: 24 ± 13 pg/mL, hall daylight white: 22 ± 26 pg/mL. Subjective alertness was significantly increased after exposure to three of the lighting conditions which included blue spectral components in their spectra. Evening exposure to conventional lamps in an everyday setting influences melatonin excretion and alertness perception within 30 min.

  17. Lighting preferences in individual offices

    Directory of Open Access Journals (Sweden)

    João Roberto Gomes de Faria

    Full Text Available Abstract Workplaces with good daylighting offer visual comfort to users, give them a series of physiological and psychological benefits and allow good performance of visual activities, besides saving energy. However, this solution is not always adopted: lighting type preferences involve many variables besides the availability of daylight. This paper explores a case study through the analysis of questionnaire answers and computer simulations of a series of metrics related to quality of lighting with the aim of finding explanations for the lighting preferences of individual office users. The results show that, although the offices present good daylighting conditions and no glare potential, and users are satisfied with daylighting, these parameters are not sufficient to explain the predominant lighting preferences. The findings have also shown that there is no consensus about which parameters potentially cause visual comfort, while the parameters that cause discomfort are clearly identified. In addition, in this study, 49% of the preference for mixed lighting (daylight plus electrical light can be explained by the fact that mixed lighting produces better modeling than daylighting alone.

  18. STUDI SIMULASI MODEL PENERANGAN ALAMI (DAYLIGHTING RUANG PADA BANGUNAN FASILITAS PENDIDIKAN TINGGI DENGAN SUPERLITE 2.0

    Directory of Open Access Journals (Sweden)

    Hanni Elitasari Mahaputri

    2012-08-01

    Full Text Available Daylight was the only efficient source of light available for building. Therefore, architecture was dominated by the goal of creating openings large enough to distribute daylight to building interiors. It is important to understand the amount of natural light penetration when outdoor obstruction are displaced in order to propose optimum external shading strategies as design solutions. This paper presents a study of the daylight factor and daylight contourt approaches and also investigates the effect of outdoor obstruction displacement on natural-light penetration of a specific room in higher-education building facility. The interior daylight illuminance data were simulated and analyzed using Superlite 2.0. The result shows that several effects of the external obstruction displacement as shading provider, depending on transmitted natural-light penetration, which determine the better consideration option in designing landscape surround building, especially in hot humid climates. Sinar matahari merupakan sumber penerangan yang efisien bagi bangunan. Tujuan utama dalam arsitektur adalah merancang bukaan pencahayaan yang cukup besar bagi bangunan untuk mendistribusikan cahaya ke bagian dalam bangunan. Sangat penting untuk mengetahui besar penetrasi penerangan alami yang masuk ke dalam ruang bila di luar bangunan diletakkan suatu halangan sebagai salah satu solusi disain dengan mengoptimalkan strategi perancangan pem­bayangan lingkungan. Makalah ini membahas tentang kajian pendekatan faktor penerangan alami (daylight factor dan koefisien penerangan alami, serta mengamati pengaruh perletakan halangan lingkungan terhadap penetrasi penerangan alami suatu ruang fasilitas pendidikan tinggi. Data illuminasi penerangan interior disimulasikan dan dianalisa menggunakan software Superlite 2.0. Hasil penelitian menunjukkan beberapa pengaruh perletakan halangan lingkungan sebagai elemen pembayangan lingkungan berkaitan dengan penetrasi cahaya alami, yang

  19. The effect of daylight saving time options on electricity consumption of Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Karasu, Servet [Rize University, Rize Vocational School, 53100, Rize (Turkey)

    2010-09-15

    Most of the developed countries in the world use Daylight Saving Time (DST) as an energy conservation method. This study focuses on the effects of DST on electrical lighting in the buildings in Turkey. Turkey might adjust its daylight saving time to decrease energy consumption. For this purpose, five scenarios are considered and compared to status quo. The scenario with a 30-minute forward shift to single DST from April to October, stands out as the best solution to conserve electricity across the entire country. The results of the study show that maximum saving is obtained in this scenario by at least 0.7% on the consumption of lighting electricity. (author)

  20. Daylighting simulation: methods, algorithms, and resources

    Energy Technology Data Exchange (ETDEWEB)

    Carroll, William L.

    1999-12-01

    This document presents work conducted as part of Subtask C, ''Daylighting Design Tools'', Subgroup C2, ''New Daylight Algorithms'', of the IEA SHC Task 21 and the ECBCS Program Annex 29 ''Daylight in Buildings''. The search for and collection of daylighting analysis methods and algorithms led to two important observations. First, there is a wide range of needs for different types of methods to produce a complete analysis tool. These include: Geometry; Light modeling; Characterization of the natural illumination resource; Materials and components properties, representations; and Usability issues (interfaces, interoperability, representation of analysis results, etc). Second, very advantageously, there have been rapid advances in many basic methods in these areas, due to other forces. They are in part driven by: The commercial computer graphics community (commerce, entertainment); The lighting industry; Architectural rendering and visualization for projects; and Academia: Course materials, research. This has led to a very rich set of information resources that have direct applicability to the small daylighting analysis community. Furthermore, much of this information is in fact available online. Because much of the information about methods and algorithms is now online, an innovative reporting strategy was used: the core formats are electronic, and used to produce a printed form only secondarily. The electronic forms include both online WWW pages and a downloadable .PDF file with the same appearance and content. Both electronic forms include live primary and indirect links to actual information sources on the WWW. In most cases, little additional commentary is provided regarding the information links or citations that are provided. This in turn allows the report to be very concise. The links are expected speak for themselves. The report consists of only about 10+ pages, with about 100+ primary links, but

  1. Daylighting for energy conservation in an existing building under tropical climate conditions: a case study of Lai Sue Thai building Ramkhamhaeng University

    Directory of Open Access Journals (Sweden)

    Lerdlekha Tanachaikhan

    2015-12-01

    Full Text Available Daylighting using skylight has been shown to have a high potential in reducing electrical lighting energy, and could provide a more pleasant atmosphere of a daylit space. However, in hot climates, the main constraint of daylighting is the solar heat gain that contributes to major heat load for an air-conditioning system. If the balance between the beneficial light gain used to offset lighting energy requirement and heat gain from daylight is well considered, significant energy savings can be obtained. The main objective of the study is to evaluate the potential of daylighting for energy conservation in the tropics through theoretical analysis (simulation study and experimental observation. Lai Sue Thai Building (an existing and educational building located at Ramkhamkaeng University was selected as a case study. From analysis, use of daylight could reduce electrical energy in this building by up to 76% compared to the initial condition where fully lighting was supplied. Window orientation would also play an important role. Moreover, heat gain through windows due to daylighting can be controlled by overhangs and the appropriate Window-to-Wall ratio that would be about 30% for this building. An experimental study was also carried out to validate the results in a selected room. About 49% and 37% of Relative Root Mean Square Error (RRMSE were observed in light and heat measurements, respectively

  2. Lighting Energy Saving with Light Pipe in Farm Animal Production

    Directory of Open Access Journals (Sweden)

    Hans von Wachenfelt

    2015-12-01

    Full Text Available The Swedish animal production sector has potential for saving electric lighting of €4-9 million per year using efficient daylight utilisation. To demonstrate this, two light pipe systems, Velux® (house 1 and Solatube® (house 2, are installed in two identical pig houses to determine if the required light intensity, daylight autonomy (DA, and reduced electricity use for illumination can be achieved. In each house, three light sensors continuously measure the indoor daylight relative to an outdoor sensor. If the horizontal illuminance at pig height decreases below 40 lux between 08.00 and 16.00 hours, an automatic control system activates the lights, and electricity use is measured. The daylight factor (DF and DA are determined for each house, based on annual climate data. The mean annual DA of 48% and 55% is achieved for house 1 and house 2, respectively. Light pipes in house 2 have delivered significantly more DA than those in house 1. The most common illuminance range between 0 and 160 lux is recorded in both houses, corresponding to approximately 82% and 83% of daylight time for house 1 and house 2, respectively. Further, the daylighting system for house 2 has produced a uniform DF distribution between 0.05 and 0.59. The results demonstrate that considerable electric energy savings can be achieved in the animal production sector using light pipes. Saving 50% of electric lighting would correspond to 36 GWh or 2520 t CO2 per year for Sweden, but currently the energy savings are not making the investment profitable.

  3. Byron G. Rogers Federal Building Harvests Daylight and Super Savings

    Energy Technology Data Exchange (ETDEWEB)

    None

    2017-01-01

    Case study describes how the Byron G. Rogers Federal Building replaced existing T12 and T8 luminaires with LED dedicated troffers with advanced controls. Together these measures cut lighting energy use by nearly 60% in the 18-story, 791,000-square-foot facility. The new lighting control system provides automated dimming of lights down to 0% output when daylight provides adequate light levels. The project earned GSA an award for exemplary performance from the Interior Lighting Campaign in 2016.

  4. Lighting in the urban context case study: Exterior decorative lighting of St. Marko's Church in Belgrade

    Directory of Open Access Journals (Sweden)

    Đokić Lidija

    2006-01-01

    Full Text Available In the past few years more attention has been devoted to exterior decorative lighting in Belgrade. Unfortunately, illuminance is very often the only quality factor for lighting design. Lighting quality is a broader concept than illuminance (quantity of light, determined by a number of factors out of which some can and others cannot be quantitatively determined. Buildings and spaces with urban, architectural and/or style values impose certain requests for lighting design, which can either emphasize or degrade these values. The lighting designer has the obligation to respond to the imposed requests and in this way support the building concept, as well as its role in the urban context. Various possibilities of artificial lighting enable better, more effective and more interesting impressions of buildings than experienced in daylight conditions. Some of the significant possibilities of artificial lighting, which can satisfy requests imposed by urban architectural or style elements, include: The possibility to emphasize elements of style, building details or ornaments, which resemble the most important values on a building or façade. This enables elements of exceptional value to be clearly noticeable (in a greater extent than in daylight conditions; Decorative lighting allows the possibility of presenting the hierarchy of architectural or style elements, which is a contribution to the emphasis of the main idea and building spirit; ® The possibility to emphasize proportions and/or balance of the façade, making solids and voids clearly distinctive; If emphasis of the building concept is the lighting aim, it is possible to realize different impressions from the ones experienced in daylighting (lighting the facade plane which is drawn in and remains in the shadow during the day; When lighting modern architecture, decorative lighting has the possibility to promote the main idea, emphasizing proportions, valuable building parts and/or the rhythm of the

  5. Performance of a daylight redirecting glass shading system demonstration in an office building

    DEFF Research Database (Denmark)

    Appelfeld, David; Svendsen, Svend; Traberg-Borup, Steen

    2011-01-01

    This paper evaluates the daylighting performance of a prototype external dynamic integrated shading and light redirecting system. The demonstration project was carried out on a building with an open-plan office. The prototype and original façades were placed on the same floor with the same...... orientation and similar surroundings. The existing façade was used as the reference for measurements and simulations. The focus of this research project was to employ available simulation tools for the system performance evaluation. This was accompanied by measurements of the daylight conditions...... in the investigated space. The prototype system improved daylighting conditions compared to the existing shading system....

  6. Distant Measurement of Plethysmographic Signal in Various Lighting Conditions Using Configurable Frame-Rate Camera

    Directory of Open Access Journals (Sweden)

    Przybyło Jaromir

    2016-12-01

    Full Text Available Videoplethysmography is currently recognized as a promising noninvasive heart rate measurement method advantageous for ubiquitous monitoring of humans in natural living conditions. Although the method is considered for application in several areas including telemedicine, sports and assisted living, its dependence on lighting conditions and camera performance is still not investigated enough. In this paper we report on research of various image acquisition aspects including the lighting spectrum, frame rate and compression. In the experimental part, we recorded five video sequences in various lighting conditions (fluorescent artificial light, dim daylight, infrared light, incandescent light bulb using a programmable frame rate camera and a pulse oximeter as the reference. For a video sequence-based heart rate measurement we implemented a pulse detection algorithm based on the power spectral density, estimated using Welch’s technique. The results showed that lighting conditions and selected video camera settings including compression and the sampling frequency influence the heart rate detection accuracy. The average heart rate error also varies from 0.35 beats per minute (bpm for fluorescent light to 6.6 bpm for dim daylight.

  7. New tools for the evaluation of daylighting strategies and technologies

    Energy Technology Data Exchange (ETDEWEB)

    Papamichael, K.; Hitchcock, R.; Ehrlich, C.; Carroll, B.

    1998-03-01

    The use of daylight for the illumination of building interiors has the potential to enhance the quality of the environment while providing opportunities to save energy by replacing or supplementing electric lighting. Moreover, it has the potential to reduce heating and cooling loads, which offer additional energy saving opportunities as well as reductions in HVAC equipment sizing and cost. All of these benefits, however, assume proper use of daylighting strategies and technologies, whose performance depends on the context of their application. On the other hand, improper use can have significant negative effects on both comfort and energy requirements, such as increased glare and cooling loads. To ensure proper use, designers need design tools that model the dynamic nature of daylight and accurately predict performance with respect to a multitude of performance criteria, extending beyond comfort and energy to include aesthetics, cost, security, safety, etc.

  8. Artificial night lighting inhibits feeding in moths

    NARCIS (Netherlands)

    Langevelde, Van Frank; Grunsven, Van Roy H.A.; Veenendaal, Elmar M.; Fijen, Thijs P.M.

    2017-01-01

    One major, yet poorly studied, change in the environment is nocturnal light pollution, which strongly alters habitats of nocturnally active species. Artificial night lighting is often considered as driving force behind rapid moth population declines in severely illuminated countries. To understand

  9. Artificial light at night inhibits mating in a Geometrid moth

    NARCIS (Netherlands)

    van Geffen, Koert G.; van Eck, Emiel; de Boer, Rens A.; van Grunsven, Roy H.A.; Salis, Lucia; Berendse, Frank; Veenendaal, Elmar M.

    2015-01-01

    * Levels of artificial night lighting are increasing rapidly worldwide, subjecting nocturnal organisms to a major change in their environment. Many moth species are strongly attracted to sources of artificial night lighting, with potentially severe, yet poorly studied, consequences for development,

  10. Artificial light at night inhibits mating in a Geometrid moth

    NARCIS (Netherlands)

    Geffen, van K.G.; Eck, van E.; Boer, de R.; Grunsven, van R.H.A.; Salis, F.; Berendse, F.; Veenendaal, E.M.

    2015-01-01

    1.Levels of artificial night lighting are increasing rapidly worldwide, subjecting nocturnal organisms to a major change in their environment. Many moth species are strongly attracted to sources of artificial night lighting, with potentially severe, yet poorly studied, consequences for development,

  11. Optimal tree design for daylighting in residential buildings

    Energy Technology Data Exchange (ETDEWEB)

    Hongbing, Wang [College of Landscape Architecture, Beijing Forestry University, 35, East Qinghua Rd., Beijing (China); Shanghai Botanical Garden, 1111, Longwu Rd., Shanghai (China); Jun, Qin; Yonghong, Hu [Shanghai Botanical Garden, 1111, Longwu Rd., Shanghai (China); Li, Dong [College of Landscape Architecture, Beijing Forestry University, 35, East Qinghua Rd., Beijing (China)

    2010-12-15

    Urban reforestation is advocated as an efficient countermeasure to the intensification of urban heat islands. The greening and beautification of residential quarters is one of the main concerns of residents, while lighting and ventilation are two main energy-consuming building services. Hence, the tree layout in green space between buildings is important, and it is necessary to determine the relationships between trees and buildings. This study takes Shanghai as a case study to optimize tree design between residential buildings and meet good daylighting requirements. Models were made using software such as AutoCAD and SketchUp. The relationships between maximum tree height and building separation were determined. For the same building layout, there were different tree height limits according to crown shape; the order of decreasing height limits was cylindrical, conical, spherical, and inverted conical crowns. Three cases having different green space between building layouts were studied. Their maximum tree heights differed. Overall, our model helps us realize good daylighting of a building environment. The formula allows us to determine which trees to plant between buildings in that we can predict the effects of future tree growth on building daylighting. (author)

  12. Refractive integrated nonimaging solar collectors design and analysis of a novel solar-daylighting-technology

    OpenAIRE

    Pelegrini, Alexandre Vieira

    2009-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. A novel and original category of low-cost static solar-daylighting-collectors named Keywo solar energy, solar collectors, daylighting systems, nonimaging optics, Refractive Integrated Nonimaging Solar Collectors (RINSC) has been designed and thoroughly tested. The RINSC category is based on nonimaging optics and integrates several optical elements, such as prismatic arrays and light guides, i...

  13. Light-zone(s: as Concept and Tool

    Directory of Open Access Journals (Sweden)

    Merete Madsen

    2012-11-01

    Full Text Available Daylight is essential to the experience of an architectural space. Nevertheless, amongst the handful of predominantly scientific methods available to assess daylight in architecture, there are only a few considering the spatial and form-giving characteristics of daylight. This paper investigates light-zone(s as concept and tool, which can be taken as a point of departure for a new method to perceive, consider and analyse daylight in architecture. As concept, light-zone(s are areas, fields or zones of light. It is a way of considering a space’s daylight as (forms of bubbles or spheres of light, which as light-zones can be compressed, expanded, combined, exploded, etc., all according to the character of 'the meeting' between the light-zone(s and the space itself (inclusive of the space’scontent. Thus, the daylight in a space can be regarded asa composition of light-zones.As tool, light-zone(s are (spatial groupings of the lightingvariables (intensity, direction, distribution and colour, whichare significant to the space and form-giving characteristicsof light. That is to say, the light-zone(s tool is the point ofdeparture for a method of creating a spatial ‘grasp’ on daylighting variables in a given space. The relation between the light-zone(s concept and tool respectively can be described as follows: On the one level light-zone(s can be explored as an architectural idea or notion, thus belonging more to the field of architectural theory. On another more practice-driven level, light-zone(s can be articulated and specified in relation to lighting technology.

  14. Experimental analysis on a 1:2 scale model of the double light pipe, an innovative technological device for daylight transmission

    Energy Technology Data Exchange (ETDEWEB)

    Baroncini, C.; Boccia, O.; Chella, F.; Zazzini, P. [D.S.S.A.R.R. Faculty of Architecture, University ' ' G. D' Annunzio' ' Viale Pindaro 42, 65127 Pescara (Italy)

    2010-02-15

    In this paper the authors present the double light pipe, an innovative technological device, designed as an evolution of a traditional light pipe, which distributes daylight to underground areas of a building, illuminating, at the same time, the passage areas thanks to a larger collector and a second transparent pipe attached to the first one. Unlike the traditional light pipe, thanks to this double illuminating function it can be located in the middle of a room, despite its encumbrance. In this paper the technological design of the double light pipe is presented and the results of an experimental analysis on a reduced scale (1:2) model are shown. Internal illuminance data over horizontal and vertical work-planes were measured in various sky conditions with or without direct solar radiation. Being this innovative device obtained by a light pipe integrated with a second pipe, it performs like a traditional light pipe for the final room and, at the same time, illuminates the intermediate room giving it uniform and high quality light, particularly indicated for wide plant areas, such as show-rooms or museums. (author)

  15. An artificial solar spectrum substantially alters plant development compared with usual climate room irradiance spectra.

    Science.gov (United States)

    Hogewoning, Sander W; Douwstra, Peter; Trouwborst, Govert; van Ieperen, Wim; Harbinson, Jeremy

    2010-03-01

    Plant responses to the light spectrum under which plants are grown affect their developmental characteristics in a complicated manner. Lamps widely used to provide growth irradiance emit spectra which are very different from natural daylight spectra. Whereas specific responses of plants to a spectrum differing from natural daylight may sometimes be predictable, the overall plant response is generally difficult to predict due to the complicated interaction of the many different responses. So far studies on plant responses to spectra either use no daylight control or, if a natural daylight control is used, it will fluctuate in intensity and spectrum. An artificial solar (AS) spectrum which closely resembles a sunlight spectrum has been engineered, and growth, morphogenesis, and photosynthetic characteristics of cucumber plants grown for 13 d under this spectrum have been compared with their performance under fluorescent tubes (FTs) and a high pressure sodium lamp (HPS). The total dry weight of the AS-grown plants was 2.3 and 1.6 times greater than that of the FT and HPS plants, respectively, and the height of the AS plants was 4-5 times greater. This striking difference appeared to be related to a more efficient light interception by the AS plants, characterized by longer petioles, a greater leaf unfolding rate, and a lower investment in leaf mass relative to leaf area. Photosynthesis per leaf area was not greater for the AS plants. The extreme differences in plant response to the AS spectrum compared with the widely used protected cultivation light sources tested highlights the importance of a more natural spectrum, such as the AS spectrum, if the aim is to produce plants representative of field conditions.

  16. Daylighting and energy performance of a building for composite climate: An experimental study

    OpenAIRE

    Madhu Sudan; G.N. Tiwari

    2016-01-01

    The present study includes overall energy saving through thermal as well as daylighting for composite climate for the building known as SODHA BERS COMPLEX (SBC) situated at Varanasi, India. The building has been designed including all the passive concepts for thermal comfort as well daylighting to maximize the use of natural lighting for the occupants in day to day activities. This approach can be useful for multi-story building for rural and urban areas for both residential and commercial bu...

  17. Hybrid fibre lighting - directed towards a smaller ecological foot print; Hybrid fiber belysning - rettet mod et mindre oekologisk fodaftryk

    Energy Technology Data Exchange (ETDEWEB)

    Bjarklev, A; Scolari, L [DTU Fotonik, Kgs. Lyngby (Denmark); Bjarklev, A; Kjaer, T; Andersen, Jan [RUC-ENSPAC, Roskilde (Denmark); Trolle, H; Laursen, K; Riisberg, V [Designskolen Kolding, Kolding (Denmark); Ibsen, P [IBSEN El-anlaeg ApS, Roskilde (Denmark)

    2010-09-15

    Building on one of the world-leading technologies in fiber optics this project uncovers, whether it is realistic under Danish conditions to exploit opportunities within hybrid fiber illumination - i.e. systems that directly moves the sun indoors via fiber optics. Hybrid lighting is a combination of four technologies: the collection of sunlight (daylight), generation of artificial light, assembly, transportation and distribution of light where needed, and operational control of both natural and artificial light. Some of the significant findings from this project are a design of a hybrid system based on a solar optical system and LED technology, and design and development of fixtures that could combine both daylight and artificial light. The analysis showed that a system based on only LEDs could save 36% energy compared with a system based on the T5 (fluorescent lamps), which today is considered the best available technology. The analysis further indicates an energy saving of 59% when you combine a solar optical system with LED technology in a hybrid system. It is found that there is great potential for further design and applications which can be based for a hybrid lighting combined with the two technologies mentioned above (optical fibers and LEDs). It was also found that hybrid lighting systems are in a very early stage of the innovation life cycle and that one of the most important barriers for successful implementation is the considerably high price. However, this is a typical problem that arises with new technologies and, therefore, further development followed by pilot test projects could bring this technology fast to a more competitive phase, even if one as the basis selects systems based on the T5 technology. There is widespread acceptance of the hybrid system by office users in many areas where it is not possible to have windows, but to make the system work in other sectors, it is necessary to continue research in design that can provide a greater light

  18. Use of Daylight and Aesthetic Image of Glass Facades in Contemporary Buildings

    Science.gov (United States)

    Roginska-Niesluchowska, Malgorzata

    2017-10-01

    The paper deals with the architecture of contemporary buildings in respect to their aesthetic image created by the use of natural light. Sustainability is regarded as a governing principle of contemporary architecture, where daylighting is an important factor as it affects energy consumption and environmental quality of the space inside a building. Environmental awareness of architecture, however, involves a much wider and more holistic view of design. The quality of sustainable architecture can be considered in its aesthetic and cultural context with regard to landscape, local tradition, and connection to the surrounding world. This approach is associated with the social mission of architecture, i.e. providing appropriate space for living, facilitating social relations and having positive impact on people. The purpose of the research is to study the use of daylight in creating an aesthetic image of contemporary buildings. The author focuses mainly on public buildings largely dedicated to art and culture which satisfy high functional and aesthetic requirements. The paper examines the genesis and current trends in the aesthetic image of modern buildings which use daylight as the main design strategy, focusing on the issues of glass facades. The main attention is given to the shaping of representative public areas which feature the glass facades. The research has been based on a case study, critical review of literature review, observation and synthesis. The study identifies and classifies different approaches to using daylight in these areas and highlights changes in the aesthetics of architecture made of glass, which uses daylight as the main design strategy. These changes are primarily caused by the development and spreading of new glazing materials and the use of digital method of design. The influence of light and its mode depends on glass materials but also on the local conditions of the site, and has a significant impact on the relationship between

  19. Light pollution reduces activity, food consumption and growth rates in a sandy beach invertebrate.

    Science.gov (United States)

    Luarte, T; Bonta, C C; Silva-Rodriguez, E A; Quijón, P A; Miranda, C; Farias, A A; Duarte, C

    2016-11-01

    The continued growth of human activity and infrastructure has translated into a widespread increase in light pollution. Natural daylight and moonlight cycles play a fundamental role for many organisms and ecological processes, so an increase in light pollution may have profound effects on communities and ecosystem services. Studies assessing ecological light pollution (ELP) effects on sandy beach organisms have lagged behind the study of other sources of disturbance. Hence, we assessed the influence of this stressor on locomotor activity, foraging behavior, absorption efficiency and growth rate of adults of the talitrid amphipod Orchestoidea tuberculata. In the field, an artificial light system was assembled to assess the local influence of artificial light conditions on the amphipod's locomotor activity and use of food patches in comparison to natural (ambient) conditions. Meanwhile in the laboratory, two experimental chambers were set to assess amphipod locomotor activity, consumption rates, absorption efficiency and growth under artificial light in comparison to natural light-dark cycles. Our results indicate that artificial light have significantly adverse effects on the activity patterns and foraging behavior of the amphipods, resulting on reduced consumption and growth rates. Given the steady increase in artificial light pollution here and elsewhere, sandy beach communities could be negatively affected, with unexpected consequences for the whole ecosystem. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Annual dynamics of daylight variability and contrast a simulation-based approach to quantifying visual effects in architecture

    CERN Document Server

    Rockcastle, Siobhan

    2013-01-01

    Daylight is a dynamic source of illumination in architectural space, creating diverse and ephemeral configurations of light and shadow within the built environment. Perceptual qualities of daylight, such as contrast and temporal variability, are essential to our understanding of both material and visual effects in architecture. Although spatial contrast and light variability are fundamental to the visual experience of architecture, architects still rely primarily on intuition to evaluate their designs because there are few metrics that address these factors. Through an analysis of contemporary

  1. Combining annual daylight simulation with photobiology data to assess the relative circadian efficacy of interior spaces

    Energy Technology Data Exchange (ETDEWEB)

    Pechacek, C.S.; Andersen, M. [Massachusetts Inst. of Technology, Cambridge, MA (United States). Dept. of Architecture, Building Technology; Lockley, S.W. [Harvard Medical School, Boston, MA (United States). Div. of Sleep Medicine, Brigham and Women' s Hospital

    2008-07-01

    This paper addressed the issue of hospital design and the role of daylight in patient health care. It presented a new approach for integrating empirical data and findings in photobiology into the performance assessment of a space, thus combining both visual and health-related criteria. Previous studies have reported significant health care outcomes in daylit environments, although the mechanism and photoreceptor systems controlling these effects remain unknown. This study focused on furthering the previous studies beyond windows to describing the characteristics of daylight that may promote human health by providing daylighting for the appropriate synchronization of circadian rhythms, and then make specific daylighting recommendations, grounded in biological findings. In particular, this study investigated the use of daylight autonomy (DA) to simulate the probabilistic and temporal potential of daylight for human health needs. Results of photobiology research were used to define threshold values for lighting, which were then used as goals for simulations. These goals included spectrum, intensity and timing of light at the human eye. The study investigated the variability of key architectural decisions in hospital room design to determine their influence on achieving the goals. The simulations showed how choices in building orientation, window size, user-window position and interior finishes affect the circadian efficacy of a space. Design decisions can improve or degrade the health potential for the space considered. While the findings in this research were specific to hospitals, the results can be applied to other building types such as office buildings and residences. 33 refs., 7 figs.

  2. Artificial light harvesting by dimerized Möbius ring

    Science.gov (United States)

    Xu, Lei; Gong, Z. R.; Tao, Ming-Jie; Ai, Qing

    2018-04-01

    We theoretically study artificial light harvesting by a Möbius ring. When the donors in the ring are dimerized, the energies of the donor ring are split into two subbands. Because of the nontrivial Möbius boundary condition, both the photon and acceptor are coupled to all collective-excitation modes in the donor ring. Therefore, the quantum dynamics in the light harvesting is subtly influenced by dimerization in the Möbius ring. It is discovered that energy transfer is more efficient in a dimerized ring than that in an equally spaced ring. This discovery is also confirmed by a calculation with the perturbation theory, which is equivalent to the Wigner-Weisskopf approximation. Our findings may be beneficial to the optimal design of artificial light harvesting.

  3. Weather conditions and daylight-mediated photodynamic therapy

    DEFF Research Database (Denmark)

    Wiegell, S R; Fabricius, S; Heydenreich, J

    2013-01-01

    Photodynamic therapy (PDT) is an attractive therapy for nonmelanoma skin cancers and actinic keratoses (AKs). Daylight-mediated methyl aminolaevulinate PDT (daylight-PDT) is a simple and painless treatment procedure for PDT. All daylight-PDT studies have been performed in the Nordic countries...

  4. Empirical assessment of a prismatic daylight-redirecting window film in a full-scale office testbed

    Energy Technology Data Exchange (ETDEWEB)

    Thanachareonkit, Anothai; Lee, Eleanor S.; McNeil, Andrew

    2013-08-31

    Daylight redirecting systems with vertical windows have the potential to offset lighting energy use in deep perimeter zones. Microstructured prismatic window films can be manufactured using low-cost, roll-to-roll fabrication methods and adhered to the inside surface of existing windows as a retrofit measure or installed as a replacement insulating glass unit in the clerestory portion of the window wall. A clear film patterned with linear, 50-250 micrometer high, four-sided asymmetrical prisms was fabricated and installed in the south-facing, clerestory low-e, clear glazed windows of a full-scale testbed facility. Views through the film were distorted. The film was evaluated in a sunny climate over a two-year period to gauge daylighting and visual comfort performance. The daylighting aperture was small (window-towall ratio of 0.18) and the lower windows were blocked off to isolate the evaluation to the window film. Workplane illuminance measurements were made in the 4.6 m (15 ft) deep room furnished as a private office. Analysis of discomfort glare was conducted using high dynamic range imaging coupled with the evalglare software tool, which computes the daylight glare probability and other metrics used to evaluate visual discomfort. The window film was found to result in perceptible levels of discomfort glare on clear sunny days from the most conservative view point in the rear of the room looking toward the window. Daylight illuminance levels at the rear of the room were significantly increased above the reference window condition, which was defined as the same glazed clerestory window but with an interior Venetian blind (slat angle set to the cut-off angle), for the equinox to winter solstice period on clear sunny days. For partly cloudy and overcast sky conditions, daylight levels were improved slightly. To reduce glare, the daylighting film was coupled with a diffusing film in an insulating glazing unit. The diffusing film retained the directionality of the

  5. Continuous activation of PpIX by daylight is as effective as and less painful than conventional photodynamic therapy for actinic keratoses; a randomized, controlled, single-blinded study

    DEFF Research Database (Denmark)

    Wiegell, S.R.; Hædersdal, Merete; Philipsen, P.A.

    2008-01-01

    of the face and scalp were treated with MAL-PDT in two symmetrical areas. One area was illuminated by red LED light (37 J cm(-2)) after 3-h incubation with MAL under occlusive dressing. The other area was treated with daylight for 2.5 h after the MAL cream had been under occlusion for half an hour. Results We...... found no significant difference in the treatment effect between the two treatments (P = 0.13), with a reduction of AK lesions of 79% in the daylight area compared with 71% in the LED area. Treatment response in the daylight area did not depend on the intensity of the daylight. Illumination with LED...... of porphyrins during its formation. Objectives The objective of this randomized controlled study was to compare response rates and adverse effects after methyl aminolevulinate (MAL)-PDT using conventional red light-emitting diode (LED) light vs. daylight. Patients/methods Twenty-nine patients with AK...

  6. Daylight calculations using constant luminance curves

    Energy Technology Data Exchange (ETDEWEB)

    Betman, E. [CRICYT, Mendoza (Argentina). Laboratorio de Ambiente Humano y Vivienda

    2005-02-01

    This paper presents a simple method to manually estimate daylight availability and to make daylight calculations using constant luminance curves calculated with local illuminance and irradiance data and the all-weather model for sky luminance distribution developed in the Atmospheric Science Research Center of the University of New York (ARSC) by Richard Perez et al. Work with constant luminance curves has the advantage that daylight calculations include the problem's directionality and preserve the information of the luminous climate of the place. This permits accurate knowledge of the resource and a strong basis to establish conclusions concerning topics related to the energy efficiency and comfort in buildings. The characteristics of the proposed method are compared with the method that uses the daylight factor. (author)

  7. Fuzzy-Neural Automatic Daylight Control System

    Directory of Open Access Journals (Sweden)

    Grif H. Şt.

    2011-12-01

    Full Text Available The paper presents the design and the tuning of a CMAC controller (Cerebellar Model Articulation Controller implemented in an automatic daylight control application. After the tuning process of the controller, the authors studied the behavior of the automatic lighting control system (ALCS in the presence of luminance disturbances. The luminance disturbances were produced by the authors in night conditions and day conditions as well. During the night conditions, the luminance disturbances were produced by turning on and off a halogen desk lamp. During the day conditions the luminance disturbances were produced in two ways: by daylight contributions changes achieved by covering and uncovering a part of the office window and by turning on and off a halogen desk lamp. During the day conditions the luminance disturbances, produced by turning on and off the halogen lamp, have a smaller amplitude than those produced during the night conditions. The luminance disturbance during the night conditions was a helpful tool to select the proper values of the learning rate for CMAC controller. The luminance disturbances during the day conditions were a helpful tool to demonstrate the right setting of the CMAC controller.

  8. Lighting Assessment in Knitting Workshop in Yazd

    Directory of Open Access Journals (Sweden)

    A Barkhordari

    2016-01-01

    Full Text Available Introduction: The sense of sight is one of the most vital human senses and help the environment gets most of its information. Whatever one's job is more subtle, more work will be given brightness. Good lighting, increase work efficiency and general physiological effects on people's moods. The relationship between low and high frequency illumination accidents there Methods: This study was conducted in 10 workshops in Yazd home knitting. Due to maximize natural lighting measurements in June and November this year took place in cloudy days. Thus, in both seasons overall lighting, natural and artificial, were evaluated. That, in order to measure all the natural light, artificial light sources (lamps and the measurements were off by clarifying re-lamp, the overall lighting (natural and artificial were measured. In order to measure the general lighting provided by the Illuminating Engineering society and stop the pattern surfaces were used. The workshops with less than standard lighting conditions were identified and interventions to improve the brightness of the workshops were measured again. Results: Average, minimum and maximum overall brightness of spring workshops 4 and 6 respectively, with values of 67/278 and 53/452 is a luxury. Workshops values 5 and 2 47/184 and 43/218 minimum and maximum luxury in order to be daylight in spring. Conclusions: The majority of the studied weaving Workshops lighting was good, with measures such as proper installation and periodic cleaning and dust lamps, replacement lamps burned by use of fluorescent ambient lighting conditions can be improved.

  9. Daylight artificial light and people in an office environment, overview of visual and biological responses

    NARCIS (Netherlands)

    Begemann, S.H.A.; Beld, van den G.J.; Tenner, A.D.

    1997-01-01

    Abstract Long-term behaviour/response of people has been studied in standard window zone offices during daytime working hours. Regular cell-offices were equipped with experimental lighting systems delivering lighting conditions that are known to influence human physiology. The results show that most

  10. Window design : visual and thermal consequences : analysis of the thermal and daylighting performance of windows

    NARCIS (Netherlands)

    Bergem-Jansen, P.M. van; Soeleman, R.S.

    1979-01-01

    Selected results of an analysis for the thermal and lighting requirements associated with windows in utility buildings are presented. This analysis concerns the effects of r¡indow size and shape, orientation and of different ways of supplementing the daylight by artifieial light for a typical office

  11. Effect of spectral composition of artificial light on the attraction of moths

    NARCIS (Netherlands)

    Langevelde, van F.; Ettema, J.A.; Donners, M.; Wallis de Vries, M.F.; Groenendijk, D.

    2011-01-01

    During the last decades, artificial night lighting has increased globally, which largely affected many plant and animal species. So far, current research highlights the importance of artificial light with smaller wavelengths in attracting moths, yet the effect of the spectral composition of

  12. Making daylighting work. Learning from failures to improve the design and implementation process

    Energy Technology Data Exchange (ETDEWEB)

    Vaidya, Prasad; McDougall, Tom; Steinbock, Jason; Douglas, James; Eijadi, David [The Weidt Group, Berkeley, CA (United States)

    2005-07-01

    Daylighting, hailed as a cornerstone of sustainable building design, is the primary passive solar design strategy in commercial buildings. It has the potential to significantly reduce lighting energy, which can be 40% or more of the energy cost of a commercial building. We have found that projects with daylighting often do not provide the expected energy savings. In a risk-averse construction industry, even limited failures can dramatically slow the advance of valid technologies. There are numerous reasons for failure: natural light sources are complex and vary through the day and year; implementation requires coordination between different building design and construction trades; the documentation and specification of the controls equipment is often inadequate; and calibration after installation is rarely done well and can be confusing and time consuming. In this paper, we provide four case studies as representative examples where daylighting did not deliver the expected energy savings. We identify the primary modes of failure and provide a template for each mode for easier problem resolution in the future. Through a detailed analysis of the case studies, we identify problem areas in the design and implementation process; we propose a more generalized solution set for design steps, documentation requirements and implementation checks that increase the chances of success.

  13. Data from: Artificial night lighting inhibits feeding in moths

    NARCIS (Netherlands)

    Langevelde, van F.; Grunsven, van R.H.A.; Veenendaal, E.M.; Fijen, T.P.M.

    2017-01-01

    One major, yet poorly studied, change in the environment is nocturnal light pollution, which strongly alters habitats of nocturnally active species. Artificial night lighting is often considered as driving force behind rapid moth population declines in severely illuminated countries. To understand

  14. Tuning the diurnal natural daylight with phosphor converted white LED – Advent of new phosphor blend composition

    International Nuclear Information System (INIS)

    Kim, Yoon Hwa; Arunkumar, Paulraj; Park, Seung Hyok; Yoon, Ho Shin; Im, Won Bin

    2015-01-01

    Highlights: • Designed phosphor blend that mimics diurnal daylight for health benefits. • Developed new phosphor blend composition that mimics natural sunlight under near UV. • The phosphor blend also exhibits high CRI (≥90) under blue LED excitation. • Fabricated WLED exhibited ∼91% spectral resemblance with daylight at 4500 K. • While ∼39.2% spectral resemblance were observed for YAG:Ce 3+ at 4500 K. - Abstract: We demonstrate the feasibility of developing phosphor converted white LED (pc-WLED) that mimics diurnal natural daylight with the newly designed phosphor blend in the color temperature (CCT) 2700–6000 K for health benefits. Natural daylight (sunlight) spectrum possesses broad emission in the visible region and closely approximates black body radiator, with color rendition index (CRI) of 100 under wide CCT (2500–6500 K). Current white light LEDs although are efficient and durable, they are not broad enough compared to daylight. We report new phosphor blend based on Sr 3 MgSi 2 O 8 :Eu 2+ blue phosphor with broad emission and high CRI ≥ 96 under both near UV and blue excitation. The fabricated WLED has exhibited ∼91% spectral resemblance with natural daylight compared to 39.2% for YAG:Ce 3+ white LED at 4500 K. The developed phosphor blend tunes the spectrum in wider CCT and would be a prospective candidate for full spectrum daylight WLED

  15. Daylight and absenteeism--evidence from Norway.

    Science.gov (United States)

    Markussen, Simen; Røed, Knut

    2015-01-01

    Based on administrative register data from Norway, we examine the impact of hours of daylight on sick-leave absences among workers. Our preferred estimates imply that an additional hour of daylight increases the daily entry rate to absenteeism by 0.5 percent and the corresponding recovery rate by 0.8 percent, ceteris paribus. The overall relationship between absenteeism and daylight hours is negative. Absenteeism is also sensitive to weather conditions. Heavy snowfall raises the incidence of absence during the winter, while warm weather reduces the probability of returning to work during the summer. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Artificial light at night alters trophic interactions of intertidal invertebrates.

    Science.gov (United States)

    Underwood, Charlotte N; Davies, Thomas W; Queirós, Ana M

    2017-07-01

    Despite being globally widespread in coastal regions, the impacts of light pollution on intertidal ecosystems has received little attention. Intertidal species exhibit many night-time-dependent ecological strategies, including feeding, reproduction, orientation and predator avoidance, which are likely negatively affected by shifting light regimes, as has been observed in terrestrial and aquatic taxa. Coastal lighting may shape intertidal communities through its influence on the nocturnal foraging activity of dogwhelks (Nucella lapillus), a widespread predatory mollusc that structures biodiversity in temperate rocky shores. In the laboratory, we investigated whether the basal and foraging activity of this predator was affected by exposure to night-time lighting both in the presence and absence of olfactory predator cues (Carcinus maenas, common shore crab). Assessments of dogwhelks' behavioural responses to night-time white LED lighting were performed on individuals that had been acclimated to night-time white LED lighting conditions for 16 days and individuals that had not previously been exposed to artificial light at night. Dogwhelks acclimated to night-time lighting exhibited natural refuge-seeking behaviour less often compared to control animals, but were more likely to respond to and handle prey irrespective of whether olfactory predator cues were present. These responses suggest night-time lighting likely increased the energetic demand of dogwhelks through stress, encouraging foraging whenever food was available, regardless of potential danger. Contrastingly, whelks not acclimated under night-time lighting were more likely to respond to the presence of prey under artificial light at night when olfactory predator cues were present, indicating an opportunistic shift towards the use of visual instead of olfactory cues in risk evaluation. These results demonstrate that artificial night-time lighting influences the behaviour of intertidal fauna such that the

  17. Artificial night light alters nocturnal prey interception outcomes for morphologically variable spiders

    Directory of Open Access Journals (Sweden)

    Suet Wai Yuen

    2017-12-01

    Full Text Available Artificial night light has the potential to significantly alter visually-dependent species interactions. However, examples of disruptions of species interactions through changes in light remain rare and how artificial night light may alter predator–prey relationships are particularly understudied. In this study, we examined whether artificial night light could impact prey attraction and interception in Nephila pilipes orb weaver spiders, conspicuous predators who make use of yellow color patterns to mimic floral resources and attract prey to their webs. We measured moth prey attraction and interception responses to treatments where we experimentally manipulated the color/contrast of spider individuals in the field (removed yellow markings and also set up light manipulations. We found that lit webs had lower rates of moth interception than unlit webs. Spider color, however, had no clear impact on moth interception or attraction rates in lit nor unlit webs. The results show that night light can reduce prey interception for spiders. Additionally, this study highlights how environmental and morphological variation can complicate simple predictions of ecological light pollution’s disruption of species interactions.

  18. Artificial night light alters nocturnal prey interception outcomes for morphologically variable spiders.

    Science.gov (United States)

    Yuen, Suet Wai; Bonebrake, Timothy C

    2017-01-01

    Artificial night light has the potential to significantly alter visually-dependent species interactions. However, examples of disruptions of species interactions through changes in light remain rare and how artificial night light may alter predator-prey relationships are particularly understudied. In this study, we examined whether artificial night light could impact prey attraction and interception in Nephila pilipes orb weaver spiders, conspicuous predators who make use of yellow color patterns to mimic floral resources and attract prey to their webs. We measured moth prey attraction and interception responses to treatments where we experimentally manipulated the color/contrast of spider individuals in the field (removed yellow markings) and also set up light manipulations. We found that lit webs had lower rates of moth interception than unlit webs. Spider color, however, had no clear impact on moth interception or attraction rates in lit nor unlit webs. The results show that night light can reduce prey interception for spiders. Additionally, this study highlights how environmental and morphological variation can complicate simple predictions of ecological light pollution's disruption of species interactions.

  19. Mitochondrial damage and cytoskeleton reorganization in human dermal fibroblasts exposed to artificial visible light similar to screen-emitted light.

    Science.gov (United States)

    Rascalou, Adeline; Lamartine, Jérôme; Poydenot, Pauline; Demarne, Frédéric; Bechetoille, Nicolas

    2018-05-05

    Artificial visible light is everywhere in modern life. Social communication confronts us with screens of all kinds, and their use is on the rise. We are therefore increasingly exposed to artificial visible light, the effects of which on skin are poorly known. The purpose of this study was to model the artificial visible light emitted by electronic devices and assess its effect on normal human fibroblasts. The spectral irradiance emitted by electronic devices was optically measured and equipment was developed to accurately reproduce such artificial visible light. Effects on normal human fibroblasts were analyzed on human genome microarray-based gene expression analysis. At cellular level, visualization and image analysis were performed on the mitochondrial network and F-actin cytoskeleton. Cell proliferation, ATP release and type I procollagen secretion were also measured. We developed a device consisting of 36 LEDs simultaneously emitting blue, green and red light at distinct wavelengths (450 nm, 525 nm and 625 nm) with narrow spectra and equivalent radiant power for the three colors. A dose of 99 J/cm 2 artificial visible light was selected so as not to induce cell mortality following exposure. Microarray analysis revealed 2984 light-modulated transcripts. Functional annotation of light-responsive genes revealed several enriched functions including, amongst others, the "mitochondria" and "integrin signaling" categories. Selected results were confirmed by real-time quantitative PCR, analyzing 24 genes representing these two categories. Analysis of micro-patterned culture plates showed marked fragmentation of the mitochondrial network and disorganization of the F-actin cytoskeleton following exposure. Functionally, there was considerable impairment of cell growth and spread, ATP release and type I procollagen secretion in exposed fibroblasts. Artificial visible light induces drastic molecular and cellular changes in normal human fibroblasts. This may impede

  20. Tuning the diurnal natural daylight with phosphor converted white LED – Advent of new phosphor blend composition

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yoon Hwa [School of Materials Science and Engineering, Chonnam National University, 300, Yongbong-dong, Buk-gu, Gwangju 500-757 (Korea, Republic of); Research Institute, Force4 Corp., Daechon-dong, Buk-gu, Gwangju 500-470 (Korea, Republic of); Arunkumar, Paulraj [School of Materials Science and Engineering, Chonnam National University, 300, Yongbong-dong, Buk-gu, Gwangju 500-757 (Korea, Republic of); Park, Seung Hyok; Yoon, Ho Shin [Research Institute, Force4 Corp., Daechon-dong, Buk-gu, Gwangju 500-470 (Korea, Republic of); Im, Won Bin, E-mail: imwonbin@jnu.ac.kr [School of Materials Science and Engineering, Chonnam National University, 300, Yongbong-dong, Buk-gu, Gwangju 500-757 (Korea, Republic of)

    2015-03-15

    Highlights: • Designed phosphor blend that mimics diurnal daylight for health benefits. • Developed new phosphor blend composition that mimics natural sunlight under near UV. • The phosphor blend also exhibits high CRI (≥90) under blue LED excitation. • Fabricated WLED exhibited ∼91% spectral resemblance with daylight at 4500 K. • While ∼39.2% spectral resemblance were observed for YAG:Ce{sup 3+} at 4500 K. - Abstract: We demonstrate the feasibility of developing phosphor converted white LED (pc-WLED) that mimics diurnal natural daylight with the newly designed phosphor blend in the color temperature (CCT) 2700–6000 K for health benefits. Natural daylight (sunlight) spectrum possesses broad emission in the visible region and closely approximates black body radiator, with color rendition index (CRI) of 100 under wide CCT (2500–6500 K). Current white light LEDs although are efficient and durable, they are not broad enough compared to daylight. We report new phosphor blend based on Sr{sub 3}MgSi{sub 2}O{sub 8}:Eu{sup 2+} blue phosphor with broad emission and high CRI ≥ 96 under both near UV and blue excitation. The fabricated WLED has exhibited ∼91% spectral resemblance with natural daylight compared to 39.2% for YAG:Ce{sup 3+} white LED at 4500 K. The developed phosphor blend tunes the spectrum in wider CCT and would be a prospective candidate for full spectrum daylight WLED.

  1. Light Pipe Transporter for High-rise Office Building in Tropical Climate

    Directory of Open Access Journals (Sweden)

    Christopher Yii Sern Heng

    2016-01-01

    Full Text Available Daylight has known to bring benefits for human, psychologically and physiologically. It also provides better indoor environment quality and thus increase the performance and productivity of office workers as stated by Paevere (2009. However, due to economic reasons, the current practice of using deep open plan building has cause a dent to having daylight in the interior spaces, which cause a dependency on artificial lighting. Hence, to provide daylight in deep interior, light distribution system is needed. Although so, according to Hansen (2003, most of the systems can only illuminate up to 8m-10m depth. Therefore, light pipe (LP plays an essential role where it can illuminate up to 20m depth. LP’s efficiency depends on the 3 main components; collector, transporter and extractor. This research explores the effectiveness of horizontal LP through different type of transporter’s shapes which includes rectangular, triangular, square and semi-circle. Previous studies have shown differences of efficiency on the shaped while using vertical LP. This research’s analysis was done using a computer simulation, Integrated Environment Solution: Virtual Environment (IESVE, where DF of each shapes were compared to MS 1525:2007 benchmark. The viability of the software was also validated though an assessment with a physical scaled-model experiment that was conducted in an open car park in Universiti Teknologi Malaysia, Johor, Malaysia. The results from the simulation showed that semi-circle shaped transporter offered the same efficiency as rectangular shaped. These findings will promote the usage of LP in buildings as it decreases the costing for LP.

  2. Teaching the Absorption of Light Colours Using an Artificial Rainbow

    Science.gov (United States)

    Yurumezoglu, Kemal; Isik, Hakan; Arikan, Gizem; Kabay, Gozde

    2015-01-01

    This paper presents an experimental activity based on the absorption of light colours by pigments. The activity is constructed using a stepwise design and offers an opportunity for students and teachers to compare and generalize the interactions between light and pigment colours. The light colours composing an artificial rainbow produced in the…

  3. Essence of Daylight in the Cistercian Monastic Church of S. Bento de Cástris, Évora, Portugal

    Science.gov (United States)

    Martins, Ana M. T.; Carlos, Jorge S.

    2017-10-01

    Natural light in the Cistercian churches is closely linked not only with the liturgical requirements at the “officium” but also with the canonical hours based on the "ora et labora" dictated by the Rule of St. Benedict. The Cistercian architecture, in its beginnings (12th century forward) is characterized by austerity, simplicity and the play of light and shadow that gives value to the monastic architectural space itself, making it perfect for a contemplative experience. In the Cistercian Monastery the church is the central piece of the monastic building. Nave, transept and apse are the main architectural components to which is added the choir. This paper contextualizes the importance and close connections of natural light, within the Cistercian Monasteries architecture. Thus the essence of daylight is analysed within the Church of the Monastery of S. Bento de Cástris, in Évora, Portugal. This former Monastery (13th - 19th centuries) includes the church, at the south-eastern corner which has not only a high choir, but also a low lateral choir (within the presbytery). Its unchanged exterior walls are made of solid masonry. Although the function of the walls is primarily structural, the windows allow the daylight to penetrate the space of the church. The church has two external façades facing northeast and southeast. The combined orientation effect of the church’s main axis and the sun trajectory determines how the sunlight reaches the interior of this architectural structure. This study presents the qualitative and quantitative analysis of the luminous environment in the church of S. Bento de Cástris, being the first based on the authors’ perception of the effect of the daylight within the different areas of the enclosed space. The appreciation of the spatial experiences was supported by quantitative daylight simulations that were conducted in selected areas within the space. With this paper is intended to contribute to the debate about the specificity

  4. Estimation of exterior vertical daylight for the humid tropic of Kota Kinabalu city in East Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Djamila, Harimi; Ming, Chu Chi; Kumaresan, Sivakumar [School of Engineering and Information Technology, Universiti Malaysia Sabah, Locked Bag No. 2073, 88999 Kota Kinabalu, Sabah (Malaysia)

    2011-01-15

    In tropical regions natural daylight has been a fundamental factor in building design. It is the most efficient way of lighting a building in the daytime and has a great potential for energy conservation in buildings. In Malaysia there are a limited available data of measured illuminance which is the case of several regions in the tropics. Using established models it is possible to predict the luminous efficacy and then estimate the monthly mean hourly exterior illuminance. In this study two different models were chosen. The Perez and Du Mortier-Perraudeau-Page-Littlefair models were selected for the prediction of hourly exterior horizontal illuminance for the city of Kota Kinabalu in East Malaysia. Comparison between the two models were made. The vertical hourly illuminance was predicted also using Perez approach. The potentiality of daylight in four orientations was discussed. This study highlights the importance of Sunpath diagram on daylight illuminance during the conceptual design stage. The results in this study is hoped to contribute further insight into the potentiality of daylighting of tropical sky. (author)

  5. Technology Assessments of High Performance Envelope with Optimized Lighting, Solar Control, and Daylighting

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eleanor S.; Thanachareonkit, Anothai; Touzani, Samir; Dutton, Spencer; Shackelford, Jordan; Dickerhoff, Darryl; Selkowitz, Stephen

    2016-09-01

    The objective of this monitored field study was to identify near-term innovative façade technologies for solar control and daylighting with a goal of 20-40% energy use savings below Title 24 2013 in the 30-ft deep perimeter zone near vertical windows within cost and comfort constraints. The targeted market was new or existing commercial office buildings or buildings with similar patterns of use.

  6. Literature Review of the Effects of Natural Light on Building Occupants

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, L.; Torcellini, P.

    2002-07-01

    This paper presents summary findings from a literature search of the term ''daylighting''-using natural light in a building to offset or replace electric lighting. According to the Department of Energy's Office of Building Technology, State and Community Programs 2000 BTS Core Databook, in 1998, commercial buildings consumed 32% of the total electricity in the United States, of which more than one-third went to lighting. Using daylighting systems and turning off the lights will help reduce this energy load. Electrical lighting adds to both the electrical and cooling loads in a commercial building. Utility costs can be decreased when daylighting is properly designed to replace electrical lighting. Along with the importance of energy savings, studies have demonstrated the non-energy-related benefits of daylighting. We compiled the data from books, periodicals, Internet articles, and interviews. The books, periodicals, and Internet articles provided the background information used to identify the main subjects of the paper. The interviews provided us with details related to specific buildings and companies that have integrated daylighting into their buildings.

  7. Multiobjective generalized extremal optimization algorithm for simulation of daylight illuminants

    Science.gov (United States)

    Kumar, Srividya Ravindra; Kurian, Ciji Pearl; Gomes-Borges, Marcos Eduardo

    2017-10-01

    Daylight illuminants are widely used as references for color quality testing and optical vision testing applications. Presently used daylight simulators make use of fluorescent bulbs that are not tunable and occupy more space inside the quality testing chambers. By designing a spectrally tunable LED light source with an optimal number of LEDs, cost, space, and energy can be saved. This paper describes an application of the generalized extremal optimization (GEO) algorithm for selection of the appropriate quantity and quality of LEDs that compose the light source. The multiobjective approach of this algorithm tries to get the best spectral simulation with minimum fitness error toward the target spectrum, correlated color temperature (CCT) the same as the target spectrum, high color rendering index (CRI), and luminous flux as required for testing applications. GEO is a global search algorithm based on phenomena of natural evolution and is especially designed to be used in complex optimization problems. Several simulations have been conducted to validate the performance of the algorithm. The methodology applied to model the LEDs, together with the theoretical basis for CCT and CRI calculation, is presented in this paper. A comparative result analysis of M-GEO evolutionary algorithm with the Levenberg-Marquardt conventional deterministic algorithm is also presented.

  8. A web-based virtual lighting simulator

    Energy Technology Data Exchange (ETDEWEB)

    Papamichael, Konstantinos; Lai, Judy; Fuller, Daniel; Tariq, Tara

    2002-05-06

    This paper is about a web-based ''virtual lighting simulator,'' which is intended to allow architects and lighting designers to quickly assess the effect of key parameters on the daylighting and lighting performance in various space types. The virtual lighting simulator consists of a web-based interface that allows navigation through a large database of images and data, which were generated through parametric lighting simulations. At its current form, the virtual lighting simulator has two main modules, one for daylighting and one for electric lighting. The daylighting module includes images and data for a small office space, varying most key daylighting parameters, such as window size and orientation, glazing type, surface reflectance, sky conditions, time of the year, etc. The electric lighting module includes images and data for five space types (classroom, small office, large open office, warehouse and small retail), varying key lighting parameters, such as the electric lighting system, surface reflectance, dimming/switching, etc. The computed images include perspectives and plans and are displayed in various formats to support qualitative as well as quantitative assessment. The quantitative information is in the form of iso-contour lines superimposed on the images, as well as false color images and statistical information on work plane illuminance. The qualitative information includes images that are adjusted to account for the sensitivity and adaptation of the human eye. The paper also includes a section on the major technical issues and their resolution.

  9. Impact of windows and daylight exposure on overall health and sleep quality of office workers: a case-control pilot study.

    Science.gov (United States)

    Boubekri, Mohamed; Cheung, Ivy N; Reid, Kathryn J; Wang, Chia-Hui; Zee, Phyllis C

    2014-06-15

    This research examined the impact of daylight exposure on the health of office workers from the perspective of subjective well-being and sleep quality as well as actigraphy measures of light exposure, activity, and sleep-wake patterns. Participants (N = 49) included 27 workers working in windowless environments and 22 comparable workers in workplaces with significantly more daylight. Windowless environment is defined as one without any windows or one where workstations were far away from windows and without any exposure to daylight. Well-being of the office workers was measured by Short Form-36 (SF-36), while sleep quality was measured by Pittsburgh Sleep Quality Index (PSQI). In addition, a subset of participants (N = 21; 10 workers in windowless environments and 11 workers in workplaces with windows) had actigraphy recordings to measure light exposure, activity, and sleep-wake patterns. Workers in windowless environments reported poorer scores than their counterparts on two SF-36 dimensions--role limitation due to physical problems and vitality--as well as poorer overall sleep quality from the global PSQI score and the sleep disturbances component of the PSQI. Compared to the group without windows, workers with windows at the workplace had more light exposure during the workweek, a trend toward more physical activity, and longer sleep duration as measured by actigraphy. We suggest that architectural design of office environments should place more emphasis on sufficient daylight exposure of the workers in order to promote office workers' health and well-being.

  10. Mapping lightscapes: spatial patterning of artificial lighting in an urban landscape.

    Science.gov (United States)

    Hale, James D; Davies, Gemma; Fairbrass, Alison J; Matthews, Thomas J; Rogers, Christopher D F; Sadler, Jon P

    2013-01-01

    Artificial lighting is strongly associated with urbanisation and is increasing in its extent, brightness and spectral range. Changes in urban lighting have both positive and negative effects on city performance, yet little is known about how its character and magnitude vary across the urban landscape. A major barrier to related research, planning and governance has been the lack of lighting data at the city extent, particularly at a fine spatial resolution. Our aims were therefore to capture such data using aerial night photography and to undertake a case study of urban lighting. We present the finest scale multi-spectral lighting dataset available for an entire city and explore how lighting metrics vary with built density and land-use. We found positive relationships between artificial lighting indicators and built density at coarse spatial scales, whilst at a local level lighting varied with land-use. Manufacturing and housing are the primary land-use zones responsible for the city's brightly lit areas, yet manufacturing sites are relatively rare within the city. Our data suggests that efforts to address light pollution should broaden their focus from residential street lighting to include security lighting within manufacturing areas.

  11. Hybrid artificial photosynthetic systems comprising semiconductors as light harvesters and biomimetic complexes as molecular cocatalysts.

    Science.gov (United States)

    Wen, Fuyu; Li, Can

    2013-11-19

    Solar fuel production through artificial photosynthesis may be a key to generating abundant and clean energy, thus addressing the high energy needs of the world's expanding population. As the crucial components of photosynthesis, the artificial photosynthetic system should be composed of a light harvester (e.g., semiconductor or molecular dye), a reduction cocatalyst (e.g., hydrogenase mimic, noble metal), and an oxidation cocatalyst (e.g., photosystem II mimic for oxygen evolution from water oxidation). Solar fuel production catalyzed by an artificial photosynthetic system starts from the absorption of sunlight by the light harvester, where charge separation takes place, followed by a charge transfer to the reduction and oxidation cocatalysts, where redox reaction processes occur. One of the most challenging problems is to develop an artificial photosynthetic solar fuel production system that is both highly efficient and stable. The assembly of cocatalysts on the semiconductor (light harvester) not only can facilitate the charge separation, but also can lower the activation energy or overpotential for the reactions. An efficient light harvester loaded with suitable reduction and oxidation cocatalysts is the key for high efficiency of artificial photosynthetic systems. In this Account, we describe our strategy of hybrid photocatalysts using semiconductors as light harvesters with biomimetic complexes as molecular cocatalysts to construct efficient and stable artificial photosynthetic systems. We chose semiconductor nanoparticles as light harvesters because of their broad spectral absorption and relatively robust properties compared with a natural photosynthesis system. Using biomimetic complexes as cocatalysts can significantly facilitate charge separation via fast charge transfer from the semiconductor to the molecular cocatalysts and also catalyze the chemical reactions of solar fuel production. The hybrid photocatalysts supply us with a platform to study the

  12. Fatal attraction of short-tailed shearwaters to artificial lights.

    Directory of Open Access Journals (Sweden)

    Airam Rodríguez

    Full Text Available Light pollution is increasing around the world and altering natural nightscapes with potential ecological and evolutionary consequences. A severe ecological perturbation caused by artificial lights is mass mortalities of organisms, including seabird fledglings that are attracted to lights at night on their first flights to the sea. Here, we report on the number of fledging short-tailed shearwaters Ardenna tenuirostris found grounded in evening and morning rescue patrols conducted at Phillip Island, Australia, during a 15-year period (1999-2013. We assessed factors affecting numbers of grounded birds and mortality including date, moon phase, wind direction and speed, number of visitors and holiday periods. We also tested experimentally if birds were attracted to lights by turning the lights off on a section of the road. Of 8871 fledglings found, 39% were dead or dying. This mortality rate was 4-8 times higher than reported elsewhere for other shearwater species, probably because searching for fledglings was part of our systematic rescue effort rather than the opportunistic rescue used elsewhere. Thus, it suggests that light-induced mortality of seabirds is usually underestimated. We rescued more birds (dead and alive in peak fledging, moonless and windy nights. Mortality increased through the fledging period, in the mornings and with increased traffic on holiday periods. Turning the road lights off decreased the number of grounded birds (dead and alive. While moon, wind and time are uncontrolled natural constraints, we demonstrated that reduction of light pollution and better traffic management can mitigate artificial light-induced mortality.

  13. Development of new types of sun shielding systems based on daylight conducting sun shielding glass slats; Udvikling af nye typer solafskaermningssystemer baseret paa dagslysdirigerende solafskaermende glaslameller

    Energy Technology Data Exchange (ETDEWEB)

    Iversen, A.; Svendsen, Svend (Danmarks Tekniske Univ., DTU Byg, Kgs. Lyngby (Denmark)); Laustsen, J.B. (NIRAS A/S (Denmark)); Traberg-Borup, S.; Johnsen, Kjeld (Statens Byggeforskningsinstitut, Aalborg Univ. (Denmark))

    2009-11-15

    The project has developed a new solar shading system consisting of reflective reflective glass slats, which both must act as general sun shading and also be able to improve daylight conditions inside the building when it's needed, by reflecting light further into the room. Simulations with the program IESve / Radiance are performed of daylight conditions in an office room using the developed solar shading concept. The calculation model is used to optimize the glass slat system's shape and dimensions (slat angle, width and distance). The calculations have shown that a slat angle of 30 degrees gives the best daylight conducting effect in overcast weather. At this position, compared with the same facade without sun shading, a slight reduction of daylight factor close to the windows is obtained while the back of the room is largely unchanged. Compared with traditional slat systems the reflective glass slats provide higher daylight factors in the building. Daylight measurements are performed in a daylight laboratory. Measurements show that the daylight factor in cloudy weather is reduced by approx. 20% 1.2 m from the facade where there are usually plenty of light while it is unchanged or slightly higher at the back of the room where there often are problems with too little daylight. On a clear day with direct sunlight and the reflective slats in shading position the result is a reduction of illumination through the whole room. The developed sun shading system reduces sun irradiance in reflective position without diminishing daylight conditions in the building under overcast conditions when the slats are angled in daylight conducting position. The glass slat system's effect on the thermal indoor environment and energy consumption are analyzed using calculations in the program BSim and by measurements of the sun shading system mounted in the Passys test cell at the Technical University of Denmark. (ln)

  14. The supermarket of the future saves energy. Shop links food refrigeration to room temperature control, and supplements artificial lighting with daylight; Supermarkt der Zukunft spart Energie. Laden koppelt Lebensmittelkuehlung mit Raumtemperierung und ergaenzt die Beleuchtung durch Tageslicht

    Energy Technology Data Exchange (ETDEWEB)

    Gintars, Dorothee

    2013-07-01

    The energy savings division at the discount store Aldi Sued in Rastatt should in the future only need two-thirds of the primary energy usually required for refrigeration, heating, ventilation, air conditioning and lighting. A compressor pack with carbon dioxide as a coolant which has been developed in-house, and which is coupled to borehole heat exchangers, not only cools food, but also provides temperature control for indoor areas. The energy concept, which has been developed at the ISE Fraunhofer Institute for Solar Energy Systems, is rounded off by a well insulated building envelope, the use of daylight and efficient ventilation. In the third year of operation, the amount of energy consumed is coming close to the ambitious target levels. (orig.)

  15. Autonomous physics-based color learning under daylight

    Science.gov (United States)

    Berube Lauziere, Yves; Gingras, Denis J.; Ferrie, Frank P.

    1999-09-01

    An autonomous approach for learning the colors of specific objects assumed to have known body spectral reflectances is developed for daylight illumination conditions. The main issue is to be able to find these objects autonomously in a set of training images captured under a wide variety of daylight illumination conditions, and to extract their colors to determine color space regions that are representative of the objects' colors and their variations. The work begins by modeling color formation under daylight using the color formation equations and the semi-empirical model of Judd, MacAdam and Wyszecki (CIE daylight model) for representing the typical spectral distributions of daylight. This results in color space regions that serve as prior information in the initial phase of learning which consists in detecting small reliable clusters of pixels having the appropriate colors. These clusters are then expanded by a region growing technique using broader color space regions than those predicted by the model. This is to detect objects in a way that is able to account for color variations which the model cannot due to its limitations. Validation on the detected objects is performed to filter out those that are not of interest and to eliminate unreliable pixel color values extracted from the remaining ones. Detection results using the color space regions determined from color values obtained by this procedure are discussed.

  16. Daylighting Design in Classroom Based on Yearly-Graphic Analysis

    Directory of Open Access Journals (Sweden)

    Yang Guan

    2016-07-01

    Full Text Available In China, existing buildings comprise more than 40 billion square meters, most being of high energy consumption. A substantial reduction in electrical energy costs could be obtained through greater use of daylight. Daylight varies widely due to the movement of sun, changing seasons and diverse weather conditions. Custom static daylight assessments, simulations represent only one time of the year or one time of the day, are inadequate to evaluate the dynamics of daylight variability. Using the intuitive graphic tool Temporal Map to display the annual daylight data, this study compared different passive architectural design strategies under the climate conditions of five representative Chinese cities and selected the most suitable design scheme for each city. In this study, the dynamic yearly-graphic tool was utilized for architectural design in China, and we integrated the optimal design with the Chinese academic calendar to achieve improvements within the occupancy time. This modified map connects design work with human activity that makes daylight evaluation more accurate and efficient. The results of this study will provide preliminary recommendations for energy-saving design in China, and reference to other similar studies.

  17. Analysis of daylight calculated using the EnergyPlus programme

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, Greici; Ghisi, Enedir [Universidade Federal de Santa Catarina, Departamento de Engenharia Civil, Laboratorio de Eficiencia Energetica em Edificacoes, Caixa Postal 476, Florianopolis - SC 88040-900 (Brazil)

    2010-09-15

    In order to properly evaluate the thermal energy performance of buildings it is also necessary to analyse the use of daylight, since this influences the thermal load of a building. In this context, the aim of this study was to evaluate the calculation of internal illuminances carried out using the EnergyPlus simulation programme. The analysis was carried out through a comparison of the Useful Daylight Illuminances (UDI) and the daylight factor (DF) estimated using the EnergyPlus programme with the results from another two programmes: Daysim/Radiance and TropLux. Also, the external horizontal illuminance estimated using EnergyPlus was compared with that measured in Florianopolis, Santa Catarina State, Brazil, between 2003 and 2005. The simulations were carried out for three different rooms: one square (5 m x 5 m x 3 m), one shallow rectangular (10 m x 5 m x 3 m) and one deep rectangular (5 m x 10 m x 3 m). From this analysis it was verified that the EnergyPlus programme has a problem related to both the DF and the external illuminance values. A comparison between the DF values calculated using the three programmes shows that there is a problem in EnergyPlus related to solving the internal reflection, such that the greater the importance of the portion of light reflected, the greater the difference found between the programmes. A comparison between the calculated and measured external horizontal illuminances shows differences greater than 100% both for the diffuse and direct illuminances indicating that the EnergyPlus programme overestimates these values. (author)

  18. The daylighting dashboard - A simulation-based design analysis for daylit spaces

    Energy Technology Data Exchange (ETDEWEB)

    Reinhart, Christoph F. [Harvard University, Graduate School of Design, 48 Quincy Street, Cambridge, MA 02138 (United States); Wienold, Jan [Fraunhofer Institute for Solar Energy Systems, Heidenhofstrasse 2, 79110 Freiburg (Germany)

    2011-02-15

    This paper presents a vision of how state-of-the-art computer-based analysis techniques can be effectively used during the design of daylit spaces. Following a review of recent advances in dynamic daylight computation capabilities, climate-based daylighting metrics, occupant behavior and glare analysis, a fully integrated design analysis method is introduced that simultaneously considers annual daylight availability, visual comfort and energy use: Annual daylight glare probability profiles are combined with an occupant behavior model in order to determine annual shading profiles and visual comfort conditions throughout a space. The shading profiles are then used to calculate daylight autonomy plots, energy loads, operational energy costs and green house gas emissions. The paper then shows how simulation results for a sidelit space can be visually presented to simulation non-experts using the concept of a daylighting dashboard. The paper ends with a discussion of how the daylighting dashboard could be practically implemented using technologies that are available today. (author)

  19. Mathematical model quantifies multiple daylight exposure and burial events for rock surfaces using luminescence dating

    International Nuclear Information System (INIS)

    Freiesleben, Trine; Sohbati, Reza; Murray, Andrew; Jain, Mayank; Al Khasawneh, Sahar; Hvidt, Søren; Jakobsen, Bo

    2015-01-01

    Interest in the optically stimulated luminescence (OSL) dating of rock surfaces has increased significantly over the last few years, as the potential of the method has been explored. It has been realized that luminescence-depth profiles show qualitative evidence for multiple daylight exposure and burial events. To quantify both burial and exposure events a new mathematical model is developed by expanding the existing models of evolution of luminescence–depth profiles, to include repeated sequential events of burial and exposure to daylight. This new model is applied to an infrared stimulated luminescence-depth profile from a feldspar-rich granite cobble from an archaeological site near Aarhus, Denmark. This profile shows qualitative evidence for multiple daylight exposure and burial events; these are quantified using the model developed here. By determining the burial ages from the surface layer of the cobble and by fitting the new model to the luminescence profile, it is concluded that the cobble was well bleached before burial. This indicates that the OSL burial age is likely to be reliable. In addition, a recent known exposure event provides an approximate calibration for older daylight exposure events. This study confirms the suggestion that rock surfaces contain a record of exposure and burial history, and that these events can be quantified. The burial age of rock surfaces can thus be dated with confidence, based on a knowledge of their pre-burial light exposure; it may also be possible to determine the length of a fossil exposure, using a known natural light exposure as calibration. - Highlights: • Evidence for multiple exposure and burial events in the history of a single cobble. • OSL rock surface dating model improved to include multiple burial/exposure cycles. • Application of the new model quantifies burial and exposure events.

  20. Proposal of the Tubular Daylight System Using Acrylonitrile Butadiene Styrene (ABS Metalized with Aluminum for Reflective Tube Structure

    Directory of Open Access Journals (Sweden)

    Anderson Diogo Spacek

    2018-01-01

    Full Text Available In the search for alternatives to reduce the consumption of electric energy, the possibility of using natural light for lighting through TDD (tubular daylight devices or TDGS (tubular daylight guidance systems appears. These natural luminaires are used in rooms where you want to save electricity and enjoy the benefits of natural light. The present work proposes the construction of a tubular system for the conduction of natural light that replaces aluminum with silver (currently marketed by several companies by polymer metallized with aluminum, offering a low cost. The polymer acrylonitrile butadiene styrene (ABS, coated with aluminum by physical vapor deposition (ionization, was evaluated for some tests to verify characteristics of the structure and the metallized surface. After the tests, the construction of the reflective tube was performed and validated in a real scale of application. The results proved the technical viability of the proposed tube construction for the realization of direct sunlight for illumination using polymeric material. Although it has produced 35% less than the reference tube, it can be marketed at an estimated cost of 50% less.

  1. Light-scattering properties of a woven shade-screen material used for daylighting and solar heat-gain control

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, Jacob; Jonsson, Jacob C.; Lee, Eleanor S.; Rubin, Mike

    2008-08-01

    Shade-screens are widely used in commercial buildings as a way to limit the amount of direct sunlight that can disturb people in the building. The shade screens also reduce the solar heat-gain through glazing the system. Modern energy and daylighting analysis software such as EnergyPlus and Radiance require complete scattering properties of the scattering materials in the system. In this paper a shade screen used in the LBNL daylighting testbed is characterized using a photogoniometer and a normal angle of incidence integrating sphere. The data is used to create a complete bi-directional scattering distribution function (BSDF) that can be used in simulation programs. The resulting BSDF is compared to a model BADFs, both directly and by calculating the solar heat-gain coefficient for a dual pane system using Window 6.

  2. Assessment of building facade performance in terms of daylighting and the associated energy consumption in architectural spaces: Vertical and horizontal shading devices for southern exposure facades

    Energy Technology Data Exchange (ETDEWEB)

    Alzoubi, Hussain H.; Al-Zoubi, Amneh H. [Department of Architecture, Jordan University of Science and Technology, Irbid 22110 (Jordan)

    2010-08-15

    This paper examines the effect of vertical and horizontal shading devices on the quality of daylight in buildings and the associated energy saving. Excessive daylight in architectural spaces contributes negatively to the energy consumption in buildings. Blinds and shading devices are good solutions to attenuate the surplus amount of daylight in spaces. Accordingly, this study evaluates the effect of shading devices on the amount of light flux and the associated solar energy in buildings. It estimates the energy consumption attributed to lighting spaces for three common positions of shading devices. Computer simulation strategy was undertaken to correlate the illuminance level in spaces with room geometry and architectural shading elements. The Holophane model for lighting calculations was used to estimate the average illuminance level on workplane and correlate it with the expected saving energy in buildings. The study concluded that there is an optimal orientation for shading devices that keeps the internal illuminance level within the acceptable range with minimum amount of solar heat gain. (author)

  3. Activity patterns during food provisioning are affected by artificial light in free living great tits (Parus major.

    Directory of Open Access Journals (Sweden)

    Mieke Titulaer

    Full Text Available Artificial light may have severe ecological consequences but there is limited experimental work to assess these consequences. We carried out an experimental study on a wild population of great tits (Parus major to assess the impact of light pollution on daily activity patterns during the chick provisioning period. Pairs that were provided with a small light outside their nest box did not alter the onset, cessation or duration of their working day. There was however a clear effect of artificial light on the feeding rate in the second half of the nestling period: when provided with artificial light females increased their feeding rate when the nestlings were between 9 and 16 days old. Artificial light is hypothesised to have affected the perceived photoperiod of either the parents or the offspring which in turn led to increased parental care. This may have negative fitness consequences for the parents, and light pollution may thus create an ecological trap for breeding birds.

  4. Illumination properties and energy savings of a solar fiber optic lighting system balanced by artificial lights

    OpenAIRE

    Lingfors, David

    2013-01-01

    A solar fiber optic lighting system, SP3 from the Swedish company Parans Solar Lighting AB, has been installed in a study area/corridor test site. A collector is tracking the sun during daytime, focusing the direct sun irradiance via Fresnel lenses into optical fibers, which guide the solar light into the building. The illumination properties of the system have been characterized. The energy saving due to reduced need of artificial lighting have been calculated and methods for balancing the a...

  5. Lighting.

    Energy Technology Data Exchange (ETDEWEB)

    United States. Bonneville Power Administration.

    1992-09-01

    Since lighting accounts for about one-third of the energy used in commercial buildings, there is opportunity to conserve. There are two ways to reduce lighting energy use: modify lighting systems so that they used less electricity and/or reduce the number of hours the lights are used. This booklet presents a number of ways to do both. Topics covered include: reassessing lighting levels, reducing lighting levels, increasing bulb & fixture efficiency, using controls to regulate lighting, and taking advantage of daylight.

  6. Daylighting and energy performance of a building for composite climate: An experimental study

    Directory of Open Access Journals (Sweden)

    Madhu Sudan

    2016-12-01

    Full Text Available The present study includes overall energy saving through thermal as well as daylighting for composite climate for the building known as SODHA BERS COMPLEX (SBC situated at Varanasi, India. The building has been designed including all the passive concepts for thermal comfort as well daylighting to maximize the use of natural lighting for the occupants in day to day activities. This approach can be useful for multi-story building for rural and urban areas for both residential and commercial buildings. The energy saving potential and corresponding CO2 mitigation have been determined for different lifetimes of the building. The energy matrices namely energy payback time (EPBT, energy production factor (EPF and life cycle conversion efficiency (LCCE of the building have also been estimated by considering overall energy saving. An annual energy saving has been obtained as 3675.61 kW h due to daylight concept by considering different Zones in each floors of the building. Further, the EPBT has been determined as 49.25 years and 34.73 years for average 4 °C and 6 °C temperature difference between ambient and room, respectively. It has been found that when thermal heat gain increases in the building LCCE and EPF increase.

  7. Innovative lighting in school buildings for the 'Frisse School'. The importance of lighting in school buildings for student performance; Innovatieve schoolverlichting voor de 'Frisse School'. Verlichting belangrijk voor optimale schoolprestaties

    Energy Technology Data Exchange (ETDEWEB)

    De Groot, E.; Westerlaken, N. [Business Unit Bouw en Installaties, TNO Bouw en Ondergrond, Delft (Netherlands); De Bruin-Hordijk, T. [Faculteit Bouwkunde, Technische Universiteit Delft, Delft (Netherlands)

    2007-11-15

    The quality of lighting plays an important role in the psychological and biological processes of people. Research shows that student performace increases in a good visual environment. At the same time, the energy use of artificial lighting is one of the major cost items of schools. This was a major reason to conduct research into optimal utilisation of daylight in schools.(mk) [Dutch] De lichtkwaliteit speelt een belangrijke rol bij de psychologische en biologische processen van mensen. Uit onderzoek blijkt dat in een goede visuele omgeving de prestaties van leerlingen toenemen. Gelijktijdig is het energiegebruik voor kunstlicht een van de belangrijkste kostenposten van scholen. Alle reden om onderzoek te doen naar optimaal gebruik van daglicht in scholen.

  8. Energy optimised lighting in buildings with simultaneous improvement of quality of life by daylight utilisation and innovative lamps and ballast techniques; Energieoptimierte Beleuchtung bei gleichzeitiger Verbesserung der Lebensqualitaet durch Nutzung von Tageslicht und neuer Lampen- und Vorschalttechnik

    Energy Technology Data Exchange (ETDEWEB)

    Kaase, Heinrich; Aydinli, Sirri; Gramm, Stefan; Thiel, Stefan [Technische Universitaet Berlin, Fakultaet IV Elektrotechnik und Informatik, FG Lichttechnik, Berlin (Germany); De Boer, Jan; Erhorn, Hans [Fraunhofer-Institut fuer Bauphysik, Stuttgart (Germany); Kuhn, Tilman; Wienold, Jan [Fraunhofer-Institut fuer Solare Energiesysteme, Freiburg (Germany); Hillmann, Gustav; Korolkow, Margarethe [IBUS GmbH, Berlin (Germany); Piazena, Helmut [Universitaetsklinikum Charite, Berlin (Germany)

    2012-06-15

    The scientific and technical goals of this project were developed in five parts. The individual topics arising from current issues, they still have a generally applicable nature. The consortium has worked on the following subprojects: (1) Development of a measurement technique to determine energy and photometric key figures of daylight components with a round robin test with three institutes. (2) Implementation of a detailed evaluation and documentation process for daylighting of interior spaces in different climate zones. (3) For lighting control in private living areas a ''Power Line Carrier Communication'' system has been evaluated and the advantages of a wireless transmission system were identified. (4) In a home for elderly quantitative studies on the well-being, for the fulfillment of visual tasks and the capability of melatonin suppression at different scenarios of general lighting with two different color temperatures of lamps (''warm white'' with TCP = 3000 K and ''cold white daylight'' with TCP = 6500 K) and vertical illuminance at the eyes of the subjects between 100 lx and 700 lx were performed. (5) For two school buildings in Berlin, the final energy consumption of the existing lighting system, the reference building and a re-planning were determined. It became clear in both examples that the existing lighting system exceeds the permitted value (EnEV 2009) by far. A good redesign, however, can be significantly less than the maximum allowed value. These studies were accompanied by a one-year monitoring of energy consumption. A cross-sectional analysis of 48 schools with a total of 86 buildings shows a substantial need for renovation of school buildings that were built before 1990.

  9. Daylight Saving Time Transitions and Road Traffic Accidents

    Directory of Open Access Journals (Sweden)

    Tuuli Lahti

    2010-01-01

    Full Text Available Circadian rhythm disruptions may have harmful impacts on health. Circadian rhythm disruptions caused by jet lag compromise the quality and amount of sleep and may lead to a variety of symptoms such as fatigue, headache, and loss of attention and alertness. Even a minor change in time schedule may cause considerable stress for the body. Transitions into and out of daylight saving time alter the social and environmental timing twice a year. According to earlier studies, this change in time-schedule leads to sleep disruption and fragmentation of the circadian rhythm. Since sleep deprivation decreases motivation, attention, and alertness, transitions into and out of daylight saving time may increase the amount of accidents during the following days after the transition. We studied the amount of road traffic accidents one week before and one week after transitions into and out of daylight saving time during years from 1981 to 2006. Our results demonstrated that transitions into and out of daylight saving time did not increase the number of traffic road accidents.

  10. Exposure of tropical ecosystems to artificial light at night: Brazil as a case study

    Science.gov (United States)

    Bennie, Jon; Mantovani, Waldir; Gaston, Kevin J.

    2017-01-01

    Artificial nighttime lighting from streetlights and other sources has a broad range of biological effects. Understanding the spatial and temporal levels and patterns of this lighting is a key step in determining the severity of adverse effects on different ecosystems, vegetation, and habitat types. Few such analyses have been conducted, particularly for regions with high biodiversity, including the tropics. We used an intercalibrated version of the Defense Meteorological Satellite Program’s Operational Linescan System (DMSP/OLS) images of stable nighttime lights to determine what proportion of original and current Brazilian vegetation types are experiencing measurable levels of artificial light and how this has changed in recent years. The percentage area affected by both detectable light and increases in brightness ranged between 0 and 35% for native vegetation types, and between 0 and 25% for current vegetation (i.e. including agriculture). The most heavily affected areas encompassed terrestrial coastal vegetation types (restingas and mangroves), Semideciduous Seasonal Forest, and Mixed Ombrophilous Forest. The existing small remnants of Lowland Deciduous and Semideciduous Seasonal Forests and of Campinarana had the lowest exposure levels to artificial light. Light pollution has not often been investigated in developing countries but our data show that it is an environmental concern. PMID:28178352

  11. Exposure of tropical ecosystems to artificial light at night: Brazil as a case study.

    Science.gov (United States)

    Freitas, Juliana Ribeirão de; Bennie, Jon; Mantovani, Waldir; Gaston, Kevin J

    2017-01-01

    Artificial nighttime lighting from streetlights and other sources has a broad range of biological effects. Understanding the spatial and temporal levels and patterns of this lighting is a key step in determining the severity of adverse effects on different ecosystems, vegetation, and habitat types. Few such analyses have been conducted, particularly for regions with high biodiversity, including the tropics. We used an intercalibrated version of the Defense Meteorological Satellite Program's Operational Linescan System (DMSP/OLS) images of stable nighttime lights to determine what proportion of original and current Brazilian vegetation types are experiencing measurable levels of artificial light and how this has changed in recent years. The percentage area affected by both detectable light and increases in brightness ranged between 0 and 35% for native vegetation types, and between 0 and 25% for current vegetation (i.e. including agriculture). The most heavily affected areas encompassed terrestrial coastal vegetation types (restingas and mangroves), Semideciduous Seasonal Forest, and Mixed Ombrophilous Forest. The existing small remnants of Lowland Deciduous and Semideciduous Seasonal Forests and of Campinarana had the lowest exposure levels to artificial light. Light pollution has not often been investigated in developing countries but our data show that it is an environmental concern.

  12. Integrated performance appraisal of Daylight-Europe case study buildings

    NARCIS (Netherlands)

    Hensen, J.L.M.; Clarke, J.A.; Hand, J.W.; Johnson, K.; Wittchen, K.; Madsen, C.; Compagnon, R.

    1996-01-01

    This paper describes the approach taken within the EC’s Daylight-Europe project to apply combined thermal/daylight simulations to existing building designs which are representative of European types and climate contexts. The outputs from the performance appraisals are then incorporated within design

  13. Daylight-mediated photodynamic therapy of basal cell carcinomas - an explorative study

    DEFF Research Database (Denmark)

    Wiegell, S R; Skødt, V; Wulf, H C

    2014-01-01

    BACKGROUND: Studies have shown that daylight-photodynamic therapy (PDT) is an effective treatment of actinic keratoses, nearly pain free and more convenient for both the clinics and patients. Treatment of basal cell carcinomas (BCCs) is another main indication for PDT. OBJECTIVES: The aim...... of this open, uncontrolled, prospective explorative study was to evaluate the efficacy of daylight-PDT for BCCs. METHODS: Twenty-one patients with a total of 32 BCCs located in the face, scalp, chest, back and lower leg received one cycle of daylight-methyl aminolevulinate (MAL)-PDT, consisting of two...... treatments 1 week apart. After sunscreen application and lesion preparation, MAL was applied and patients exposed themselves to daylight for 2½ h. Daylight exposure was monitored with a wrist-borne dosimeter. RESULTS: At 3-month follow-up, complete response was seen in 30 lesions (94%) and in 19 patients (90...

  14. A spatially augmented reality sketching interface for architectural daylighting design.

    Science.gov (United States)

    Sheng, Yu; Yapo, Theodore C; Young, Christopher; Cutler, Barbara

    2011-01-01

    We present an application of interactive global illumination and spatially augmented reality to architectural daylight modeling that allows designers to explore alternative designs and new technologies for improving the sustainability of their buildings. Images of a model in the real world, captured by a camera above the scene, are processed to construct a virtual 3D model. To achieve interactive rendering rates, we use a hybrid rendering technique, leveraging radiosity to simulate the interreflectance between diffuse patches and shadow volumes to generate per-pixel direct illumination. The rendered images are then projected on the real model by four calibrated projectors to help users study the daylighting illumination. The virtual heliodon is a physical design environment in which multiple designers, a designer and a client, or a teacher and students can gather to experience animated visualizations of the natural illumination within a proposed design by controlling the time of day, season, and climate. Furthermore, participants may interactively redesign the geometry and materials of the space by manipulating physical design elements and see the updated lighting simulation. © 2011 IEEE Published by the IEEE Computer Society

  15. Application of automated blind for daylighting in tropical region

    International Nuclear Information System (INIS)

    Chaiwiwatworakul, Pipat; Chirarattananon, Surapong; Rakkwamsuk, Pattana

    2009-01-01

    This paper reports an experimental and simulation study on application of automated Venetian blind for daylighting in tropical climate. A horizontal blind system operating automatically under programmed control was constructed and integrated onto the glazed windows to form a window system with an automated blind in a room of a laboratory building. A dimming controller was also integrated to the lighting system of the room. Different operation schemes of the window system were devised and tested in the attempt to maximize energy savings while maintaining the quality of the visual environment in the room. Intensive measurement of illuminance of the interior space was undertaken during the experiments. A methodology for calculation of interior daylight illuminance and associated glare corresponding to the configurations of the experiments was adopted. The method was coded into a computer program. Results of calculation from the program agree well with those from experiments for all the schemes of operation conducted. The program was used to simulate the situation when each scheme of operation was implemented for a whole year. It was found that such window system with automated blind enabled energy savings of 80%, but a more sophisticated scheme also helped maintain the interior visual quality at high level.

  16. Artificial light at night confounds broad-scale habitat use by migrating birds

    Science.gov (United States)

    McLaren, James D.; Buler, Jeffrey J.; Schreckengost, Tim; Smolinsky, Jaclyn A.; Boone, Matthew; van Loon, E. Emiel; Dawson, Deanna K.; Walters, Eric L.

    2018-01-01

    With many of the world's migratory bird populations in alarming decline, broad-scale assessments of responses to migratory hazards may prove crucial to successful conservation efforts. Most birds migrate at night through increasingly light-polluted skies. Bright light sources can attract airborne migrants and lead to collisions with structures, but might also influence selection of migratory stopover habitat and thereby acquisition of food resources. We demonstrate, using multi-year weather radar measurements of nocturnal migrants across the northeastern U.S., that autumnal migrant stopover density increased at regional scales with proximity to the brightest areas, but decreased within a few kilometers of brightly-lit sources. This finding implies broad-scale attraction to artificial light while airborne, impeding selection for extensive forest habitat. Given that high-quality stopover habitat is critical to successful migration, and hindrances during migration can decrease fitness, artificial lights present a potentially heightened conservation concern for migratory bird populations.

  17. Daylight savings time transitions and the incidence rate of unipolar depressive episodes

    DEFF Research Database (Denmark)

    Hansen, Bertel T; Sønderskov, Kim M; Hageman, Ida

    2017-01-01

    Background: Daylight savings time transitions affect approximately 1.6 billion people worldwide. Prior studies have documented associations between daylight savings time transitions and adverse health outcomes, but it remains unknown whether they also cause an increase in the incidence rate...... of depressive episodes. This seems likely because daylight savings time transitions affect circadian rhythms, which are implicated in the etiology of depressive disorder. Therefore, we investigated the effects of daylight savings time transitions on the incidence rate of unipolar depressive episodes. Methods...

  18. A statistical analysis of the energy policy act of 2005, its changes to the daylight saving program, and impact on residential energy consumption

    Science.gov (United States)

    Murray, Patrick L.

    Government programs designed to decrease resource consumption, improve productivity and capitalize on extended daylight hours in the summer have been developed and implemented throughout the world for nearly three hundred years. In 2005, The United States government adopted an extended daylight savings program that increases the number of weeks where the country observes Daylight Saving Time (DST) from 31 to 35 weeks. The program took effect in March 2007. Arguments in support of DST programs highlight the portion of electricity consumption attributed to residential lighting in the evening hours. Adjusting clocks forward by one hour in summer months is believed to reduce electricity consumption due to lighting and therefore significantly reduce residential energy consumption during the period of DST. This paper evaluates the efficacy of the changes to DST resulting from the Energy Policy Act of 2005. The study focuses on changes to household electricity consumption during the extended four weeks of DST. Arizona, one of two states that continue to opt out of DST serves as the study's control for a comparison with neighboring states, Colorado, Nebraska, Nevada, New Mexico, Oklahoma, Texas and Utah. Results from the regression analysis of a Difference in Difference model indicate that contrary to evaluations by Congress and the Department of Energy, the four week period of Extended Daylight Saving Time does not produce a significant decrease in per capita electricity consumption in Southwestern states.

  19. Effects of daylight savings time changes on stock market volatility.

    Science.gov (United States)

    Berument, M Hakan; Dogan, Nukhet; Onar, Bahar

    2010-04-01

    The presence of daylight savings time effects on stock returns and on stock volatility was investigated using an EGARCH specification to model the conditional variance. The evidence gathered from the major United States stock markets for the period between 1967 and 2007 did not support the existence of the daylight savings time effect on stock returns or on volatility. Returns on the first business day following daylight savings time changes were not lower nor was the volatility higher, as would be expected if there were an effect.

  20. Induction of cellular transformation by irradiation from artificial light sources

    International Nuclear Information System (INIS)

    Withrow, T.J.

    1981-01-01

    Cellular transformation in vitro has been used to test for the carcinogenic potential of chemical and physical insults including light. This report discusses the measurement of transformation, and reviews studies done on the effects of exposure to artificial light on cellular transformation or on cellular transformation by a virus. To date, cool-white lamps have been found to cause cellular transformation, while germicidal lamps and sunlamps have been found to cause cellular transformation and to enhance virally produced transformation

  1. Rapid microwave-assisted nonaqueous synthesis and growth mechanism of AgCl/Ag, and its daylight-driven plasmonic photocatalysis.

    Science.gov (United States)

    Jiang, Jing; Zhang, Lizhi

    2011-03-21

    We report on a rapid microwave-assisted nonaqueous synthesis and the growth mechanism of AgCl/Ag with controlled size and shape. By rationally varying the reaction temperature and the microwave irradiation time, we achieved the transformation of nanocubes to rounded triangular pyramids by a combined process of "oriented attachment" and Ostwald ripening. The surface plasmon resonance (SPR) properties of the as-prepared AgCl/Ag have been found to be somewhat dependent on the size, morphology, and composition. The as-prepared AgCl/Ag exhibits high photocatalytic activity and good reusability for decomposing organic pollutants (such as methyl orange (MO), rhodamine B (RhB), and pentachlorophenol (PCP)) under indoor artificial daylight illumination (ca. 1 mW cm(-2)). The AgCl/Ag has also been found to display a superior ability to harvest diffuse indoor daylight (ca. 5 mW cm(-2)), and could complete the degradation of 10 mg  L(-1) MO within 15 min. Experiments involving the trapping of active species have shown that the photocatalytic degradation of organic pollutants in the AgCl/Ag system may proceed through direct hole transfer. This study has revealed that plasmonic daylight photocatalysis may open a new frontier for indoor pollutant control around the clock under fluorescent lamp illumination. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Lighting Control System for Premises with Display Screen Equipment

    Science.gov (United States)

    Kudryashov, A. V.

    2017-11-01

    The use of Display Screen Equipment (DSE) at enterprises allows one to increase the productivity and safety of production, minimize the number of personnel and leads to the simplification of the work of specialists, but on the other side, changes usual working conditions. If the personnel works with displays, visual fatigue develops more quickly which contributes to the emergence of nervous tension, stress and possible erroneous actions. Low interest of the lighting control system developers towards the rooms with displays is dictated by special requirements for coverage by sanitary and hygienic standards (limiting excess workplace illumination). We decided to create a combined lighting system which works considering daylight illumination and artificial light sources. The brightness adjustment of the LED lamps is carried out according to the DALI protocol, adjustment of the natural illumination by means of smart glasses. The technical requirements for a lighting control system, the structural-functional scheme and the algorithm for controlling the operation of the system have been developed. The elements of control units, sensors and actuators have been selected.

  3. Chromatic illumination discrimination ability reveals that human colour constancy is optimised for blue daylight illuminations.

    Directory of Open Access Journals (Sweden)

    Bradley Pearce

    Full Text Available The phenomenon of colour constancy in human visual perception keeps surface colours constant, despite changes in their reflected light due to changing illumination. Although colour constancy has evolved under a constrained subset of illuminations, it is unknown whether its underlying mechanisms, thought to involve multiple components from retina to cortex, are optimised for particular environmental variations. Here we demonstrate a new method for investigating colour constancy using illumination matching in real scenes which, unlike previous methods using surface matching and simulated scenes, allows testing of multiple, real illuminations. We use real scenes consisting of solid familiar or unfamiliar objects against uniform or variegated backgrounds and compare discrimination performance for typical illuminations from the daylight chromaticity locus (approximately blue-yellow and atypical spectra from an orthogonal locus (approximately red-green, at correlated colour temperature 6700 K, all produced in real time by a 10-channel LED illuminator. We find that discrimination of illumination changes is poorer along the daylight locus than the atypical locus, and is poorest particularly for bluer illumination changes, demonstrating conversely that surface colour constancy is best for blue daylight illuminations. Illumination discrimination is also enhanced, and therefore colour constancy diminished, for uniform backgrounds, irrespective of the object type. These results are not explained by statistical properties of the scene signal changes at the retinal level. We conclude that high-level mechanisms of colour constancy are biased for the blue daylight illuminations and variegated backgrounds to which the human visual system has typically been exposed.

  4. Mathematical model quantifies multiple daylight exposure and burial events for rock surfaces using luminescence dating

    DEFF Research Database (Denmark)

    Freiesleben, Trine Holm; Sohbati, Reza; Murray, Andrew

    2015-01-01

    Interest in the optically stimulated luminescence (OSL) dating of rock surfaces has increased significantly over the last few years, as the potential of the method has been explored. It has been realized that luminescence-depth profiles show qualitative evidence for multiple daylight exposure...... and burial events. To quantify both burial and exposure events a new mathematical model is developed by expanding the existing models of evolution of luminescenceedepth profiles, to include repeated sequential events of burial and exposure to daylight. This new model is applied to an infrared stimulated...... events. This study confirms the suggestion that rock surfaces contain a record of exposure and burial history, and that these events can be quantified. The burial age of rock surfaces can thus be dated with confidence, based on a knowledge of their pre-burial light exposure; it may also be possible...

  5. Justification of Natural Lighting Management for Workplaces with Displays

    Science.gov (United States)

    Kudryashov, A. V.; Erunova, A. V.; Kalinina, A. S.

    2017-11-01

    The article is devoted to the study of the influence of the orientation of light apertures (windows) on the distribution of illumination in a room inside the workplaces equipped with displays. The measurements of natural light were carried out in two similar rooms, in the first room the windows are oriented to the north and in the second - to the south. The normative illumination value in a workplace equipped with a personal computer or display must be between 300 and 500 lux. However, during the daytime, the value of natural illumination at the workplace can exceed the normalized value by several times, and in the morning and evening hours is not sufficient. Such distribution of illumination involves the use a combined lighting control system (with daylight time control and switching on artificial lighting in the morning and evening hours). In the article it is justified that the orientation of the windows in the room does not have a significant effect on the distribution of illumination throughout the room which makes it possible not to take into account the restrictions concerning the orientation of the room’s light apertures when combined lighting control systems are used.

  6. EFICIENCIA ENERGÉTICA POR LA UTILIZACIÓN DE COMPONENTES DE CONDUCCIÓN DE LUZ NATURAL EN CLIMA CÁLIDO-HÚMEDO | ENERGETIC EFFICIENCY DERIVED FROM THE USE OF CONDUCTION COMPONENTS OF DAYLIGHT IN WARM-HUMID CLIMATE

    Directory of Open Access Journals (Sweden)

    Rosalinda González Gómez

    2015-11-01

    Full Text Available The electric energy saving was estimated by the utilization of Conduction Components of Daylight (CCD in warm-humid climate. For this, the luminic performance of the component was determined, considering values of horizontal exterior lighting and interior lighting obtained by monitoring under real sky conditions in scale models, and the comparison with incandescent bulbs and Compact Fluorescent Lamps (CFL. The utilization of the natural light through CCLN allows to obtain a saving in the expense for energy, with respect to the use of Incandescent Bulb and/or Compact Fluorescent Lamp (artificial lighting. In this sense, their use would correspond to 219 KWh and to 54.75 KWh, respectively, if they are used for an average of 10 daily hours, during a period of one year. It was estimated that a possible reduction could be achieved in the electricity consumption, maintaining the comfort and quality of life of the users in buildings (high luminic performance without use of energy from commercial supplier, contributing this way to the "energy efficiency" in them.

  7. Light-Triggered Soft Artificial Muscles: Molecular-Level Amplification of Actuation Control Signals.

    Science.gov (United States)

    Dicker, Michael P M; Baker, Anna B; Iredale, Robert J; Naficy, Sina; Bond, Ian P; Faul, Charl F J; Rossiter, Jonathan M; Spinks, Geoffrey M; Weaver, Paul M

    2017-08-23

    The principle of control signal amplification is found in all actuation systems, from engineered devices through to the operation of biological muscles. However, current engineering approaches require the use of hard and bulky external switches or valves, incompatible with both the properties of emerging soft artificial muscle technology and those of the bioinspired robotic systems they enable. To address this deficiency a biomimetic molecular-level approach is developed that employs light, with its excellent spatial and temporal control properties, to actuate soft, pH-responsive hydrogel artificial muscles. Although this actuation is triggered by light, it is largely powered by the resulting excitation and runaway chemical reaction of a light-sensitive acid autocatalytic solution in which the actuator is immersed. This process produces actuation strains of up to 45% and a three-fold chemical amplification of the controlling light-trigger, realising a new strategy for the creation of highly functional soft actuating systems.

  8. A Red-Light Running Prevention System Based on Artificial Neural Network and Vehicle Trajectory Data

    Directory of Open Access Journals (Sweden)

    Pengfei Li

    2014-01-01

    Full Text Available The high frequency of red-light running and complex driving behaviors at the yellow onset at intersections cannot be explained solely by the dilemma zone and vehicle kinematics. In this paper, the author presented a red-light running prevention system which was based on artificial neural networks (ANNs to approximate the complex driver behaviors during yellow and all-red clearance and serve as the basis of an innovative red-light running prevention system. The artificial neural network and vehicle trajectory are applied to identify the potential red-light runners. The ANN training time was also acceptable and its predicting accurate rate was over 80%. Lastly, a prototype red-light running prevention system with the trained ANN model was described. This new system can be directly retrofitted into the existing traffic signal systems.

  9. A red-light running prevention system based on artificial neural network and vehicle trajectory data.

    Science.gov (United States)

    Li, Pengfei; Li, Yan; Guo, Xiucheng

    2014-01-01

    The high frequency of red-light running and complex driving behaviors at the yellow onset at intersections cannot be explained solely by the dilemma zone and vehicle kinematics. In this paper, the author presented a red-light running prevention system which was based on artificial neural networks (ANNs) to approximate the complex driver behaviors during yellow and all-red clearance and serve as the basis of an innovative red-light running prevention system. The artificial neural network and vehicle trajectory are applied to identify the potential red-light runners. The ANN training time was also acceptable and its predicting accurate rate was over 80%. Lastly, a prototype red-light running prevention system with the trained ANN model was described. This new system can be directly retrofitted into the existing traffic signal systems.

  10. A Red-Light Running Prevention System Based on Artificial Neural Network and Vehicle Trajectory Data

    Science.gov (United States)

    Li, Pengfei; Li, Yan; Guo, Xiucheng

    2014-01-01

    The high frequency of red-light running and complex driving behaviors at the yellow onset at intersections cannot be explained solely by the dilemma zone and vehicle kinematics. In this paper, the author presented a red-light running prevention system which was based on artificial neural networks (ANNs) to approximate the complex driver behaviors during yellow and all-red clearance and serve as the basis of an innovative red-light running prevention system. The artificial neural network and vehicle trajectory are applied to identify the potential red-light runners. The ANN training time was also acceptable and its predicting accurate rate was over 80%. Lastly, a prototype red-light running prevention system with the trained ANN model was described. This new system can be directly retrofitted into the existing traffic signal systems. PMID:25435870

  11. Fabrication of thin-film thermoelectric generators with ball lenses for conversion of near-infrared solar light

    OpenAIRE

    Ito, Yoshitaka; Mizoshiri, Mizue; Mikami, Masashi; Kondo, Tasuku; Sakurai, Junpei; Hata, Seiichi

    2017-01-01

    We designed and fabricated thin-film thermoelectric generators (TEGs) with ball lenses, which separated visible light and near-infrared (NIR) solar light using a chromatic aberration. The transmitted visible light was used as daylight and the NIR light was used for thermoelectric generation. Solar light was estimated to be separated into the visible light and NIR light by a ray tracing method. 92.7% of the visible light was used as daylight and 9.9% of the NIR light was used for thermoelectri...

  12. Melatonin in sleepless children : everything has a rhythm?

    NARCIS (Netherlands)

    van Geijlswijk, I.M.

    2011-01-01

    Every living organism has an biological clock regulating endogenous melatonin production, synchronized by exogenous impulses like daylight, temperature and feeding. Inappropriately applied bright light disturbs this melatonin rhythm. Some large swine producers apply artificial light three times a

  13. Assessment of Interior and Area Artificial Lighting in Hospitals of Hamadan City

    Directory of Open Access Journals (Sweden)

    Rostam Golmohamadi

    2014-04-01

    Full Text Available Background & Objectives: Comfort lighting is one of the most important topics, which provides optimum physical conditions in general environment and workplaces such as hospitals. This study aimed to evaluate general, local and area artificial illumination of Hamadan city hospitals . Methods : In this descriptive-analytical study, general, local and area artificial illumination in seven Hamadan hospitals in 2006 were evaluated. Lighting intensities (illuminance were measured according to recommended IESNA method using the lux meter model (Lutron-Lx102 in the early hours of night. Lighting quality parameters such as color rendering, technical suitability of design and lighting uniformity were evaluated. Data was analyzed using SPSS 13 . Results : The average of interior illuminance was 90.44 ± 46.97 lx, which was lower than the national recommended limits. Maximum and minimum intensity values of interior illuminance were in nursing station and laboratory, respectively. The average of area illuminance was 47.92 ± 53.2 lx and local illuminance was 131.5 ± 60.2 lx, which were lower than the recommended limits. Maximum intensity of local illuminance was in laboratories and the minimum levels were in admitted rooms, checkup and injection units. In total, 90.6% of general interior lighting systems, 83.3% of area lighting systems and 100% of local lighting systems had unaccepted design . Conclusion : The average of general, local and area illuminance in Hamadan hospitals were not within the acceptable limits for comfort lighting. To obtain comfort lighting in studied hospitals, reforming and modifying lightening systems is necessary .

  14. Apolux : an innovative computer code for daylight design and analysis in architecture and urbanism

    Energy Technology Data Exchange (ETDEWEB)

    Claro, A.; Pereira, F.O.R.; Ledo, R.Z. [Santa Catarina Federal Univ., Florianopolis, SC (Brazil)

    2005-07-01

    The main capabilities of a new computer program for calculating and analyzing daylighting in architectural space were discussed. Apolux 1.0 was designed to use three-dimensional files generated in graphic editors in the data exchange file (DXF) format and was developed to integrate an architect's design characteristics. An example of its use in a design context development was presented. The program offers fast and flexible manipulation of video card models in different visualization conditions. The algorithm for working with the physics of light is based on the radiosity method representing the surfaces through finite elements divided in small triangular units of area which are fully confronted to each other. The form factors of each triangle are determined in relation to all others in the primary calculation. Visible directions of the sky are also included according to the modular units of a subdivided globe. Following these primary calculations, the different and successive daylighting solutions can be determined under different sky conditions. The program can also change the properties of the materials to quickly recalculate the solutions. The program has been applied in an office building in Florianopolis, Brazil. The four stages of design include initial discussion with the architects about the conceptual possibilities; development of a comparative study based on 2 architectural designs with different conceptual elements regarding daylighting exploitation in order to compare internal daylighting levels and distribution of the 2 options exposed to the same external conditions; study the solar shading devices for specific facades; and, simulations to test the performance of different designs. The program has proven to be very flexible with reliable results. It has the possibility of incorporating situations of the real sky through the input of the Spherical model of real sky luminance values. 3 refs., 14 figs.

  15. Impact of Furniture Layout on Indoor Daylighting Performance in Existing Residential Buildings in Malaysia

    Directory of Open Access Journals (Sweden)

    Seyed Mohammad Mousavi

    2018-06-01

    Full Text Available Currently, home-based computing workspaces have developed substantially all over the world, especially in Malaysia. This growing trend attracts computer workers to run a business from their residential units. Hence, visual comfort needs to be considered in addition to thermal comfort for home workers in their residential working rooms. While such rooms are always occupied with furniture, the layout of the furniture may influence the indoor daylighting distribution. Several various furniture layouts can be arranged in a residential working room. However, to have better generalisation, this study focused on the impacts of mostly-used-furniture-layouts (MUFLs on indoor daylighting performance in residential working rooms. The field measurement was conducted in a typically furnished room under a tropical sky to validate the results of the simulation software under different sky conditions. Then, daylight ratio (DR, as a quantitative daylighting variable, and the illuminance uniformity ratio (IUR, CIE glare index (CGI, and Guth visual comfort probability (GVCP, as qualitative daylighting variables, were analysed through simulation experiments. In conclusion, by changing the furniture layout, daylight uniformity recorded the highest fluctuations in the case room among all variables. While various furniture layouts, in a residential working room in the tropics, may even slightly reduce the extreme indoor daylight quantity, they can worsen the indoor daylight quality compared to an unfurnished space. The paper shows that furniture as an interior design parameter cannot help to improve tropical daylighting performance in a building.

  16. Daylighting on the working plane in oriented attic rooms under overcast and clear sky

    Directory of Open Access Journals (Sweden)

    Kondáš Kristián

    2014-06-01

    Full Text Available The evaluation of daylight conditions in building interiors is based on the Daylight Factor concept after current Slovak standards. Criteria and requirements determined in these standards consider the worst daylight exterior conditions which are described by CIE overcast sky model. The sky luminance distribution of overcast sky is centrical to the zenith, so independence of window orientation to cardinal points is characteristic in daylighting calculations. The sky luminance distribution modelling is one of the main task of the daylight source research more than 50 years. It is evident that also other types of sky conditions exist in nature. An introduction of a new criterion based on photometric variables, which also consider sunlight influence, is expected. This article represents a study of the influence of the interior orientation on distribution of daylighting in attic spaces under an overcast and clear sky

  17. Phases of daylight and the stability of color perception in the near peripheral human retina.

    Science.gov (United States)

    Panorgias, Athanasios; Kulikowski, Janus J; Parry, Neil R A; McKeefry, Declan J; Murray, Ian J

    2012-03-01

    Typical daylight extends from blue (morning sky) to orangey red (evening sky) and is represented mathematically as the Daylight Locus in color space. In this study, we investigate the impact of this daylight variation on human color vision. Thirty-eight color normal human observers performed an asymmetric color match in the near peripheral visual field. Unique hues were identified using a naming paradigm. The observers' performance for matching was almost perfectly coincident with the Daylight Locus but declined markedly in other regions. Interobserver variability reached a conspicuous minimum adjacent to the Daylight Locus and was maximal in the red and yellowish-green regions. In the naming task, unique blue and yellow were virtually coincident with the Daylight Locus. The results suggest that the mechanisms of color perception mediated by the phylogenetically older (blue-yellow) color pathway have been strongly influenced by the different phases of daylight.

  18. Theoretical and experimental analysis of daylight performance for various shading systems

    Energy Technology Data Exchange (ETDEWEB)

    Tsangrassoulis, A [Group Building Enviromental Studies, Lab. of Meteorology, Dept. of Applied Physics, Univ. of Athens (Greece); Santamouris, M [Group Building Enviromental Studies, Lab. of Meteorology, Dept. of Applied Physics, Univ. of Athens (Greece); Asimakopoulos, D [Group Building Enviromental Studies, Lab. of Meteorology, Dept. of Applied Physics, Univ. of Athens (Greece)

    1997-12-31

    The daylight coefficient approach is used for the theoretical analysis of various shading systems. Once a set of these coefficients has been calculated, it is very easy to calculate illuminance in the interior of a room under various sky luminance distributions. The present paper examines a method based on daylight coefficients to evaluate daylight in the interior of a room. The method is compared with existing radiosity and ray-tracing methods. The examined method is experimentaly validated using measurements obtained in a PASSYS test-cell equipped with shading devices. (orig.)

  19. NATURAL LIGHTING OF DEEP ARCHITECTURAL SPACE: THE PERCEPTION OF NEW ZEALAND ARCHITECTS

    Directory of Open Access Journals (Sweden)

    Richard Barrett

    2008-07-01

    Full Text Available The paper considers aspects of a survey carried out amongst a group of registered New Zealand architects in order to establish their knowledge and experience in using core-daylighting systems and methods (Barrett, 2003. Core-daylighting comprises systems and methods for bringing natural light into deep architectural space where conventional methods (such as windows and skylights cannot readily be used. Examples of these methods are: atria (Matusiak, 1998, sun tracking heliostats, sun and light pipes, light scoops, Fresnel lenses, anidolic zenithal systems, prismatic daylight systems, light shelves, tapping mirrors, light reflectors and louvres (Littlefair, 1991, 1996 & 2000, lightwells, internal courts (Lam, 1986, fibre optic cable (Kay,1999, and other systems for light re-direction. The survey was carried out using a questionnaire as described below (Survey Methods. The findings were analysed, resulting in a clear indication that the respondents were not especially experienced or knowledgeable, and a majority felt this to be an area of their skill base in need of development. Whilst the survey was strictly intended to gather quantitative material, respondents were invited to comment freely as they progressed through to completion of the questionnaire. This paper draws on this qualitative data as an insight into several areas, including the attitudes of respondents towards their clients when making decisions about designing buildings for natural daylighting.

  20. Impact of Extended Daylight Saving Time on National Energy Consumption Report to Congress

    Energy Technology Data Exchange (ETDEWEB)

    Belzer, D. B.; Hadley, S. W.; Chin, S-M.

    2008-10-01

    The Energy Policy Act of 2005 (Pub. L. No. 109-58; EPAct 2005) amended the Uniform Time Act of 1966 (Pub. L. No. 89-387) to increase the portion of the year that is subject to Daylight Saving Time. (15 U.S.C. 260a note) EPAct 2005 extended the duration of Daylight Saving Time in the spring by changing its start date from the first Sunday in April to the second Sunday in March, and in the fall by changing its end date from the last Sunday in October to the first Sunday in November. (15 U.S.C. 260a note) EPAct 2005 also called for the Department of Energy to evaluate the impact of Extended Daylight Saving Time on energy consumption in the United States and to submit a report to Congress. (15 U.S.C. 260a note) This report presents the results of impacts of Extended Daylight Saving Time on the national energy consumption in the United States. The key findings are: (1) The total electricity savings of Extended Daylight Saving Time were about 1.3 Tera Watt-hour (TWh). This corresponds to 0.5 percent per each day of Extended Daylight Saving Time, or 0.03 percent of electricity consumption over the year. In reference, the total 2007 electricity consumption in the United States was 3,900 TWh. (2) In terms of national primary energy consumption, the electricity savings translate to a reduction of 17 Trillion Btu (TBtu) over the spring and fall Extended Daylight Saving Time periods, or roughly 0.02 percent of total U.S. energy consumption during 2007 of 101,000 TBtu. (3) During Extended Daylight Saving Time, electricity savings generally occurred over a three- to five-hour period in the evening with small increases in usage during the early-morning hours. On a daily percentage basis, electricity savings were slightly greater during the March (spring) extension of Extended Daylight Saving Time than the November (fall) extension. On a regional basis, some southern portions of the United States exhibited slightly smaller impacts of Extended Daylight Saving Time on energy savings

  1. Lighting in the health care sector; Verlichting in de zorg

    Energy Technology Data Exchange (ETDEWEB)

    Visser, R. [Grontmij, Amersfoort (Netherlands)

    2009-02-15

    The importance of light for people's health and welfare attracts frequent attention, not only the professional press but also in countless articles in newspapers and news magazines. Insufficient illumination can upset the biological clock and may even cause depression. In principle this applies to anyone who has to stay indoors all day or nearly all day; in the case of care homes it affects residents who have no regular opportunity to sit at a window, for example those who are bedridden. Research indicates that we need a minimum daily portion of daylight or of artificial light with similar qualities as daylight. This is also of great importance to night workers. [Dutch] Niet alleen in de vakpers, maar ook in tal van dag- en weekbladen, wordt regelmatig het belang van licht voor het welzijn en de gezondheid van de mens aan de orde gesteld. Gebrek aan voldoende licht kan het bioritme verstoren en zelfs leiden tot depressie. Dat geldt in principe voor alle mensen die om wat voor redenen dan ook de hele dag of nagenoeg de hele dag binnen moeten blijven. In zorginstellingen is dit vooral van toepassing voor degenen die zich niet regelmatig direct achter het ream kunnen bevinden, zoals mensen die bedlegering zijn. Want door onderzoek is gebleken dat we elke dag een voldoende portie daglicht nodig hebben of licht met overeenkomstige kwaliteiten als daglicht. Voor mensen die 's nachts moeten werken is het laatstgenoemde ook van groot belang.

  2. Estimation of luminous efficacy of daylight and illuminance for composite climate

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Jamil M.; Tiwari, G.N. [Center for Energy Studies, Indian Institute of Technology, Hauz Khas, New Delhi-16 (India)

    2010-07-01

    This Daylighting is one of the basic components of passive solar building design and its estimation is essential. In India there are a few available data of measured illuminance as in many regions of the world. The Indian climate is generally clear with overcast conditions prevailing through the months of July to September, which provides good potential to daylighting in buildings. Therefore, an analytical model that would encompass the weather conditions of New Delhi was selected. Hourly exterior horizontal and slope daylight availability has been estimated for New Delhi using daylight modeling techniques based on solar radiation data. A model to estimate interior illuminance was investigated and validated using experimental hourly inside illuminance data of an existing skylight integrated vault roof mud house in composite climate of New Delhi. The interior illuminance model was found in good agreement with experimental value of interior illuminance.

  3. Light therapy: Methodological issues from an engineering perspective.

    NARCIS (Netherlands)

    Joost van Hoof; Aries; MD E.J.M. Wouters; Van Someren; Schoutens; Westerlaken; Aarts; Sinoo

    2011-01-01

    Light therapy is increasingly administered and studied as a non-pharmacologic treatment for a variety of health-related problems. Light therapy comes in a variety of ways, ranging from being exposed to daylight to being exposed to light from light boxes and ambient bright light. Light therapy is an

  4. Cutaneous leishmaniasis responds to daylight-activated photodynamic therapy

    DEFF Research Database (Denmark)

    Enk, C D; Nasereddin, A; Alper, R

    2015-01-01

    BACKGROUND: Cutaneous leishmaniasis (CL) is endemic in Israel, with hundreds of new cases reported in recent years. Photodynamic therapy (PDT) is highly effective for treatment of CL, but requires equipment available only at specialized centres. Daylight-activated PDT (DA-PDT) abolishes the need...... application of a thick layer of 16% methyl aminolaevulinate and 30-min occlusion, the lesions were exposed to daylight for 2·5 h. Treatment sessions were repeated at weekly intervals until clinical and microbiological cure. Control lesions were either treated with cryotherapy or left untreated. RESULTS...

  5. Artificial Light at Night Reduces Daily Energy Expenditure in Breeding Great Tits (Parus major)

    NARCIS (Netherlands)

    Welbers, Anouk; van Dis, Natalie; Kolvoort, Annemieke; Ouyang, J.Q.; Visser, M.E.; Spoelstra, K.; Dominoni, D.M.

    2017-01-01

    The ecological impact of artificial light at night (ALAN) is an increasingly recognized process that accompanies expanding urbanization. Yet, we have limited knowledge on the impact of ALAN on wild species, and on the potential to mitigate any negative effects by using different light sources and

  6. Modernisation of the energy supply and lighting systems of a school building at Erfurt; Energetische und lichttechnische Sanierung der Regelschule Erfurt

    Energy Technology Data Exchange (ETDEWEB)

    Russ, C. [Fraunhofer-Institut fuer Solare Energiesysteme (ISE), Freiburg im Breisgau (Germany). Gruppe Solares Bauen

    1997-12-31

    A complete energy-oriented modernization of an Erfurt type school building in large panel construction with the aid of intelligent control systems improves thermal and lighting conditions. Thermal insulation systems and efficient glazing reduce thermal energy demand by approximately 50 per cent. Equally, light-directing systems and daylight-controlled artificial lighting cut down electric energy consumption by about 50 per cent. The executed modernization, lighting system design, and ventilation requirements are discussed in detail. (MSK) [Deutsch] Anhand einer kompletten energetischen Sanierung wird der waerme und lichttechnische Zustand fuer eine Pschlattenbauschule vom Erfurter-Schultyp unter Einbeziehung intelligenter Steuersysteme verbessert. Waermedaemmung und effiziente Verglasung reduzieren den Heiwaermebedarf um ca. 50%. Lichtlenkende Systeme und eine tageslichtabhaengig gesteuerte Kunstlichtbeleuchtung minimieren die Elektroenergie ebenfalls um etwa 50%. Im Einzelnen wird auf die energetische Sanierung, auf die lichttechnische Gestaltung sowie auf den Lueftungsbedarf eingegangen.

  7. Daylight as a building material

    DEFF Research Database (Denmark)

    Thule Kristensen, Peter; Madsen, Merete

    2005-01-01

    The article draws on examples to chronologically trace the use of daylight as building material in architecture of the 20th and early 21st century. The essay covers works of Mies van der Rohe, Le Corbusier, Erik Bryggman, Rudolf Schwarz, Alvar Aalto, Aldo Rossi, Jørn Utzon, Daniel Libeskind, Peter...

  8. Daylighting Concepts for University Libraries and Their Influences on Users' Satisfaction

    Science.gov (United States)

    Kilic, Didem Kan; Hasirci, Deniz

    2011-01-01

    Daylighting, a controlled architectural tool that influences users' perception and behavior, in university libraries and their influences on users' preference and satisfaction was examined in this study. The effects of daylighting in coordination with visual comfort, on university library users were measured in relation to four environmental…

  9. External perforated Solar Screens for daylighting in residential desert buildings: Identification of minimum perforation percentages

    KAUST Repository

    Sherif, Ahmed

    2012-06-01

    The desert climate is endowed by clear sky conditions, providing an excellent opportunity for optimum utilization of natural light in daylighting building indoor spaces. However, the sunny conditions of the desert skies, in countries like Egypt and Saudi Arabia, result in the admittance of direct solar radiation, which leads to thermal discomfort and the incidence of undesired glare. One type of shading systems that is used to permit daylight while controlling solar penetration is " Solar Screens" Very little research work addressed different design aspects of external Solar Screens and their influence on daylighting performance, especially in desert conditions, although these screens proved their effectiveness in controlling solar radiation in traditional buildings throughout history.This paper reports on the outcomes of an investigation that studied the influence of perforation percentage of Solar Screens on daylighting performance in a typical residential living room of a building in a desert location. The objective was to identify minimum perforation percentage of screen openings that provides adequate illuminance levels in design-specific cases and all-year-round.Research work was divided into three stages. Stage one focused on the analysis of daylighting illuminance levels in specific dates and times, while the second stage was built on the results of the first stage, and addressed year round performance using Dynamic Daylight Performance Metrics (DDPMs). The third stage addressed the possibility of incidence of glare in specific cases where illuminance levels where found very high in some specific points during the analysis of first stage. The research examined the daylighting performance in an indoor space with a number of assumed fixed experimentation parameters that were chosen to represent the principal features of a typical residential living room located in a desert environment setting.Stage one experiments demonstrated that the screens fulfilled the

  10. IEA Task 31. Daylighting Buildings in the 21{sup st} Century

    Energy Technology Data Exchange (ETDEWEB)

    Scartezzini, J.-L.; Morel, N.; Andersen, M.; Lindelhoef, D.

    2006-02-15

    This report for the Swiss Federal Office of Energy (SFOE) takes a look at work being carried out within the framework of the International Energy Agency's Solar Heating and Cooling Programme, Task 31 concerning the daylighting of buildings. Research activities in the task's four subtasks, user perspectives and requirements, integration and optimisation of daylighting systems, daylighting design tools and performance tracking network and design support groups are reported on. Objectives, projects and outcomes of each subtask are presented. Swiss contributions to the work done in these subtasks are reviewed and main achievements due to Swiss contributions are listed. Practical examples are quoted.

  11. Light therapy: Methodological issues from an engineering perspective

    NARCIS (Netherlands)

    MD E.J.M. Wouters; AC Westerlaken; MBC Aries; AMC Schoutens; MM Sinoo; Joost van Hoof; MPJ Aarts

    2012-01-01

    Light therapy is increasingly administered and studied as a non-pharmacologic treatment for a variety of health-related problems, including treatment of people with dementia. Light therapy comes in a variety of ways, ranging from being exposed to daylight, to being exposed to light emitted by light

  12. Light therapy: Methodological issues from an engineering perspective

    NARCIS (Netherlands)

    A.C. Westerlaken; A.M.C. Schoutens; M.P.J. Aarts; M.B.C. Aries; M.M. Sinoo; J. van Hoof; E.J.M. Wouters

    2012-01-01

    Light therapy is increasingly administered and studied as a non-pharmacologic treatment for a variety of healthrelated problems, including treatment of people with dementia. Light therapy comes in a variety of ways, ranging from being exposed to daylight, to being exposed to light emitted by light

  13. Light therapy : methodological issues from an engineering perspective

    NARCIS (Netherlands)

    Hoof, van J.; Westerlaken, A.C.; Aarts, M.P.J.; Wouters, E.J.M.; Schoutens, A.M.C.; Sinoo, M.M.; Aries, M.B.C.

    2012-01-01

    Light therapy is increasingly administered and studied as a non-pharmacologic treatment for a variety of healthrelated problems, including treatment of people with dementia. Light therapy comes in a variety of ways, ranging from being exposed to daylight, to being exposed to light emitted by light

  14. Green Lighting. Energy-efficient integrated lighting systems - Final report

    Energy Technology Data Exchange (ETDEWEB)

    Linhart, F.; Scartezzini, J.-L.

    2009-10-15

    The objective of the Green Lighting project was to develop a High Performance Integrated Lighting System, based on advanced technologies for day- and electric lighting, achieving a Lighting Power Density (LPD) that does not exceed 3 W/m{sup 2}. The project has revealed that Anidolic Daylighting Systems (ADS) are an ideal basis for High Performance Integrated Lighting Systems. Not only are they able to provide adequate illumination (i.e. sufficiently high illuminance) in office rooms during large fractions of normal office hours, under various sky conditions and over the entire year, but they are also highly appreciated by office occupants at the condition that glare control mechanisms are available. Complementary electric lighting is, however, still necessary to back up the ADS at times when there is insufficient daylight flux available. It was shown during this project, that the most interesting trade-offs between energy-efficiency and visual comfort are obtained by using a combination of ceiling-mounted directly emitting luminaires with very high optical efficiencies for ambient lighting and portable desk lamps for temporary task lighting. The most appropriate lamps for the ceiling-mounted luminaires are currently highly efficient fluorescent tubes, but white LED tubes can be considered a realistic option for the future. The most suitable light sources for desk lamps for temporary task lighting are Compact Fluorescent Lamps (CFLs) and white LED light bulbs. Based on the above-mentioned technologies, a High Performance Integrated Lighting System with a very low LPD has been developed over the last three years. The system has been set up in an office room of the LESO solar experimental building located on the EPFL campus; it has been tested intensively during a Post-Occupancy Evaluation (POE) study involving twenty human subjects. This study has revealed that the subjects' performance and subjective visual comfort was improved by the new system, compared to

  15. Daylight prediction techniques in energy design tools

    Energy Technology Data Exchange (ETDEWEB)

    Milne, M.; Zurick, J. [California Univ., Los Angeles, Dept. of Architecture, CA (United States)

    1998-09-01

    Four different whole-building energy design tool systems that calculate energy savings from daylighting and that display annual performance on an-hour-by-hour basis, have been tested. The nature of design tools, the sources of hourly outdoor illuminance data, the ways of predicting indoor illumination, the assumptions of each tool, and the resulting energy savings of the design tools tested are discussed. The tests were carried out with the essential criteria for evaluating whole-building daylighting and energy design tools in mind. These have been identified as user confidence, accuracy, response time, and the amount of detail. Results of the tests, all four of them run on a single elementary school classroom for the sake of comparability, were provided. 9 refs., 2 figs.

  16. Daylight Influence on Colour Design : Empirical Study on Perceived Colour and Colour Experience Indoors

    OpenAIRE

    Hårleman, Maud

    2007-01-01

    It is known that one and the same interior colouring will appear different in rooms with windows facing north or facing south, but it is not known how natural daylight from these two compass points affects perceived colour and the ways in which colour is experienced. The objective is to describe the perceived colours to be expected in rooms with sunlight and diffused light, and thus develop a tool for colour design. Two empirical investigations provide the basis for six attached papers. The m...

  17. The effect of different weather data sets and their resolution on climate-based daylight modelling

    DEFF Research Database (Denmark)

    Iversen, A; Svendsen, Svend; Nielsen, Toke Rammer

    2013-01-01

    Climate-based daylight modelling is based on the available weather data, which means that the weather data used as input to the daylight simulations are of great importance. In this paper, the effect on the outcome of the daylight simulations of using one weather data file rather than another...

  18. OPTIMIZATION STUDY OF VISUAL COMFORT AND DAYLIGHT AVAILABILITY AT CADL ITB

    Directory of Open Access Journals (Sweden)

    SIREGAR Mhd. Akbar Anthony

    2016-12-01

    Full Text Available One way to reduce energy consumption in buildings is to use daylighting. However, daylight can cause visual discomfort in the form of glare. Center of Art, Design, and Language (CADL Institut Teknologi Bandung is a building that has windows on west and east facades, so the probability of glare occurrence is high. In this research, CADL was optimized so that the percentage of time that Daylight Glare Probability below 0.21 (%DGP<0.21 is more than 50% and spatial daylight autonomy with illuminance 150 lux and 50% (sDA150lux,50% is more than 30%. In the optimization, vertical blinds, horizontal blinds, and curtains were added. Vertical blinds and horizontal blinds were varied by changing the blade’s opening angle and area covering the windows, while curtains were varied only by changing the area covering the windows. The results show that %DGP<0.21 can be increased beyond 50%, but in some rooms, sDA150,50% also decrease below 30%. The most frequent optimum solutions are vertical blinds 75%-60o.

  19. Workshop report and proposal for a new IEA Task: Daylight in buildings

    Energy Technology Data Exchange (ETDEWEB)

    Kristensen, P E; Johnsen, K

    1994-04-01

    The IEA workshop on Daylight in Buildings was held in Copenhagen on March 14-16, 1994. At the workshop, presentations were given on key topics as a basis for discussions by the experts participating in the meeting. The presentations and discussions covered a range of technical, architectural and amenity aspects of daylighting in buildings. A great interest in research collaboration on daylight was expressed, and it was agreed that plenty of work still needs to be done, and that the appropriate form of work would be an IEA Task. It was agreed that daylighting systems and control strategies should be evaluated and tested in test rooms, as well as in existing buildings as case studies. Furthermore, the workshop expressed that one of the best ways to realize and present the Task results to practice would be through a few demonstration buildings, build in different countries and under different climatic conditions. (EG)

  20. Predicting daylight illuminance on inclined surfaces using sky luminance data

    Energy Technology Data Exchange (ETDEWEB)

    Li, D.H.W.; Lau, C.C.S.; Lam, J.C. [City University of Hong Kong, Kowloon (China). Dept. of Building and Construction

    2005-07-01

    Daylight illuminance, particularly on vertical surfaces, plays a major role in determining and evaluating the daylighting performance of a building. In many parts of the world, however, the basic daylight illuminance data for various vertical planes are not always readily available. The usual method to obtain diffuse illuminance on tilted planes would be based on inclined surface models using data from the horizontal measurements. Alternatively, the diffuse illuminance on a sloping plane can be computed by integrating the luminance distribution of the sky 'seen' by the plane. This paper presents an approach to estimate the vertical outdoor illuminance from sky luminance data and solar geometry. Sky luminance data recorded from January 1999 to December 2001 in Hong Kong and generated by two well-known sky luminance models (Kittler and Perez) were used to compute the outdoor illuminance for the four principal vertical planes (N, E, S and W). The performance of this approach was evaluated against data measured in the same period. Statistical analysis indicated that using sky luminance distributions to predict outdoor illuminance can give reasonably good agreement with measured data for all vertical surfaces. The findings provide an accurate alternative to determine the amount of daylight on vertical as well as other inclined surfaces when sky luminance data are available. (author)

  1. The chemistry of artificial lighting devices lamps, phosphors and cathode ray tubes

    CERN Document Server

    Ropp, Richard C

    2013-01-01

    Both the early use of artificial lighting and current manufacturing methods concerning incandescent and fluorescent lamps are covered in this book. The protocols for manufacture of fluorescent lamp phosphors and those used in cathode ray tubes are also treated in some detail. This text surveys the amazing, vast array of artificial lighting devices known to date in terms of how they arose and are, or have been used by mankind. A complete description of the formulations and methodology for manufacturing all known phosphors is given. The book will serve as a repository of such phosphor manufacturing methods, including that of cathode ray tube phosphors. Methods of manufacture of lamp parts are also presented, including that of tungsten wire. The original approaches used are described as well as improvements in technology. These will serve as comparative methods for present day manufacture of these components. A history of the lamp industry is presented. Several methods are given which may serve as a source for f...

  2. Daytime running lights : the attention light : a literature survey of daytime running lights for motor vehicles and their effect on road safety in The Netherlands.

    NARCIS (Netherlands)

    Polak, P.H.

    1987-01-01

    In the history of (motorised) traffic, the role of lighting has assumed increasing importance, not only at night but also during daylight hours. Studies in the U.S. and Sweden demonstrated the positive effect of daytime running lights (DRL) on traffic safety. The aim of this study is to investigate

  3. Modified optical fiber daylighting system with sunlight transportation in free space.

    Science.gov (United States)

    Vu, Ngoc-Hai; Pham, Thanh-Tuan; Shin, Seoyong

    2016-12-26

    We present the design, optical simulation, and experiment of a modified optical fiber daylighting system (M-OFDS) for indoor lighting. The M-OFDS is comprised of three sub-systems: concentration, collimation, and distribution. The concentration part is formed by coupling a Fresnel lens with a large-core plastic optical fiber. The sunlight collected by the concentration sub-system is propagated in a plastic optical fiber and then collimated by the collimator, which is a combination of a parabolic mirror and a convex lens. The collimated beam of sunlight travels in free space and is guided to the interior by directing flat mirrors, where it is diffused uniformly by a distributor. All parameters of the system are calculated theoretically. Based on the designed system, our simulation results demonstrated a maximum optical efficiency of 71%. The simulation results also showed that sunlight could be delivered to the illumination destination at distance of 30 m. A prototype of the M-OFDS was fabricated, and preliminary experiments were performed outdoors. The simulation results and experimental results confirmed that the M-OFDS was designed effectively. A large-scale system constructed by several M-OFDSs is also proposed. The results showed that the presented optical fiber daylighting system is a strong candidate for an inexpensive and highly efficient application of solar energy in buildings.

  4. Dynamic window daylighting systems: electropolymeric technology for solar responsive building envelopes

    Science.gov (United States)

    Krietemeyer, Elizabeth A.; Smith, Shane I.; Dyson, Anna H.

    2011-04-01

    Human health and energy problems associated with the lack of control of sunlight in contemporary buildings have necessitated research into dynamic windows for energy efficient buildings. Existing window technologies have made moderate progress towards greater energy performance for facades but remain limited in their response to dynamic solar conditions, building energy requirements, and variable user preferences for visual comfort. Recent developments in electropolymeric display technology provide opportunities to transfer electroactive polymers to windows that can achieve high levels of geometric and spectral selectivity through the building envelope in order to meet the lighting, thermal and user requirements of occupied spaces. Experimental simulations that investigate daylight quality, energy performance, and architectural effects of electropolymeric glazing technology are presented.

  5. Daylight levels during the solar eclipse of 11 August 1999

    Science.gov (United States)

    Darula, S.; Kambezidis, H. D.; Kittler, R.

    Solar eclipses are unique phenomena not only for astronomical and space observations but also for terrestrial; they create unique conditions of sunbeam blockage which cause not only the reduction of direct sunlight but also the dimming of skylight from the whole sky vault. Very favorable conditions were met during the recent August 1999 solar eclipse in Athens, Greece and Bratislava, Slovakia. General class daylight stations operate within the International Daylight Measurements Program in the two cities. One-minute data of global/diffuse illuminance and zenith luminance from those stations have been used to provide information about their levels and the daylight reduction rate during the eclipse. An approximate formula for the estimation of sunlight and skylight illuminance levels as well as zenith luminance using relative luminance sky patterns is also presented in this work. To achieve this, recently developed sky standards together with their parameterizations are utilized.

  6. Daylighting simulation : comparison of softwares for architect's utilization

    Energy Technology Data Exchange (ETDEWEB)

    Christakou, D.E.; Amorim, C.N.D. [Brazil Univ., Brasilia (Brazil). Faculty of Architecture and Urbanism

    2005-07-01

    This study analyzed and compared 4 daylighting software packages to determine the primary benefits and limits of each one, while considering the priorities for the use of the software by architects. The complex task of daylight simulation is an important step in designing buildings, particularly when the main objective is comfort and energy conservation. Simulation is not yet commonly practiced by professional architects because of the complexities of various software packages, the lack of user friendly interfaces and difficulty in interpreting results. The 4 software packages that were evaluated in this study were: (1) Desktop Radiance, (2) Rayfront, (3) Relux 2004 Vision, and (4) Lightscape. Criteria such as interfaces, flexibility, and help manuals were also analyzed in an effort to establish a frame of the main points to be considered when choosing daylighting software for architectural use, both in educational and office environments. Simulations of a test room were performed in which some parameters were modified to verify the performance of the following main criteria: flexibility in adapting to the architect's workflow; the use of state of the art algorithms; numerical precision; and, access possibility by Brazilian architects. The results demonstrate the potential of software's improvement, particular in terms of user interfaces and help manuals. The study showed that Relux 2004 Vision is the most adequate for architect's use. Rayfront and Desktop Radiance presented more difficulties in the design process, but Desktop Radiance had the advantage of being enclosed in AUTOCAD, a well known interface. Lightscape had a user friendly interface but was not as intuitive as Relux. It was concluded that the ideal daylighting simulation software does not yet exist. The ideal software should integrate diverse factors and combine edition and modeling tools beyond luminous evaluation and thermal consequences of daylight use. 5 refs., 3 tabs., 4 figs.

  7. Organic Light-Emitting Diode with Color Tunable between Bluish-White Daylight and Orange-White Dusk Hue

    Directory of Open Access Journals (Sweden)

    Shih-Yun Liao

    2014-01-01

    Full Text Available The varying color of sunlight diurnally exhibits an important effect on circadian rhythm of living organisms. The bluish-white daylight that is suitable for work shows a color temperature as high as 9,000 K, while the homey orange-white dusk hue is as low as 2,000 K. We demonstrate in this report the feasibility of using organic light-emitting diode (OLED technology to fabricate sunlight-style illumination with a very wide color temperature range. The color temperature can be tuned from 2,300 K to 9,300 K, for example, by changing the applied voltage from 3 to 11 V for the device composing red and yellow emitters in the first emissive layer and blue emitter in the second. Unlike the prior arts, the color-temperature span can be made much wider without any additional carrier modulation layer, which should enable a more cost effective fabrication. For example, the color-temperature span is 7,000 K for the above case, while it is 1,700 K upon the incorporation of a nanoscale hole modulation layer in between the two emissive layers. The reason why the present device can effectively regulate the shifting of recombination zone is because the first emissive layer itself possesses an effective hole modulation barrier of 0.2 eV. This also explains why the incorporation of an extra hole modulation layer with a 0.7 eV barrier did not help extend the desirable color-temperature span since excessive holes may be blocked.

  8. Influence of artificial lights on the orientation of hatchlings of Eretmochelys imbricata in Pernambuco, Brazil

    Directory of Open Access Journals (Sweden)

    Thyara Noely Simões

    2017-10-01

    Full Text Available ABSTRACT Sea turtle hatchlings, in natural abiotic conditions, emerge from their nests at night and go directly to the sea, following the moonlight’s reflection in the ocean. Increased human activities such as tourism and artificial lights on the coasts, however, have interfered with the ability of sea turtle neonates to find their correct destination, negatively affecting their survival rates. Here we endeavored to assess the influence of artificial lights on the hatchlings of the sea turtle Eretmochelys imbricata (Linnaeus, 1766 in the south coast of the state of Pernambuco, Brazil. To that end, 10 experiments were conducted with 15 hatchlings/test subjects. Five experiments took place in artificially illuminated areas and five in non-illuminated areas. Circles with a 2 m radius were drawn on the sand a small 2-3 cm depression was made at the center of each circles. The neonates were then placed in the depressions to simulate their coming from a nest. After the neonates crossed the edge of the circles, their tracks were photographed and drawn on a diagram. To ascertain if the trajectories of the neonates differed between the two groups (hatchlings from illuminated versus non-illuminated nests, the Rayleigh test was used. The significance of those differences was tested using ANOVA. To evaluate similarities and significance of clusters, a Multi-Dimensional Scaling was used. The tracks of 86.67% (N = 65 of the hatchlings from nests at illuminated areas departed from their correct trajectory. The distribution of trajectories was considered random (V = 19.4895, p > 0.05 only for tracks originating from artificially illuminated areas. The movement patterns of hatchlings from illuminated and non-illuminated areas differed significantly (F < 0.0001, p < 0.01. Consistent with this, two distinct groups were identified, one from illuminated and one from non-illuminated areas. Therefore, we conclude that artificial illumination impacts the orientation

  9. Using the whole-building design approach to incorporate daylighting into a retail space: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Hayter, S.; Torcellini, P.; Eastment, M.; Judkoff, R.

    2000-06-21

    This paper focuses on implementation of daylighting into the Bighorn Center, a collection of home improvement retail spaces in Silverthorne, Colorado, which were constructed in three phases. Daylighting was an integral part of the design of the Phase 3 building. Energy consultants optimized the daylighting design through detailed modeling using an hourly building energy simulation tool. Energy consultants also used this tool to address the building owner's concerns related to customer comfort and increased product sales.

  10. Lighting and cooling energy consumption in an open-plan office using solar film coating

    International Nuclear Information System (INIS)

    Li, Danny H.W.; Lam, Tony N.T.; Wong, S.L.; Tsang, Ernest K.W.

    2008-01-01

    In subtropical Hong Kong, solar heat gain via glazing contributes to a significant proportion of the building envelope cooling load. The principal fenestration design includes eliminating direct sunlight and reducing cooling requirements. Daylighting is an effective approach to allow a flexible building facade design strategy, and to enhance an energy-efficient and green building development. This paper studies the lighting and cooling energy performances for a fully air-conditioned open-plan office when solar control films together with daylight-linked lighting controls are being used. Measurements were undertaken at two stages including the electricity expenditures for the office using photoelectric dimming controls only (first stage) and together with the solar control film coatings on the windows (second stage). Electric lighting and cooling energy consumption, transmitted daylight illuminance and solar radiation were systematically recorded and analysed. The measured data were also used for conducting and validating the building energy simulations. The findings showed that the solar film coatings coupled with lighting dimming controls cut down 21.2% electric lighting and 6.9% cooling energy consumption for the open-plan office

  11. A randomized, multicentre study of directed daylight exposure times of 11/2 vs. 21/2 h in daylight-mediated photodynamic therapy with methyl aminolaevulinate in patients with multiple thin actinic keratoses of the face and scalp

    DEFF Research Database (Denmark)

    Wiegell, S.R.; Fabricius, S.; Philipsen, P.A.

    2011-01-01

    , time of day or time of year during which the treatment was performed. Treatment was well tolerated, with a mean ± SD maximal pain score of 1·3 ± 1·5. Conclusions: Daylight-mediated MAL-PDT is an effective, convenient and nearly pain-free treatment for patients with multiple thin AKs. Daylight-mediated......, the inconvenience of clinic attendance and discomfort during therapy are significant drawbacks. Daylight-mediated PDT could potentially reduce these and may serve as an alternative to conventional PDT. Objectives: To compare the efficacy of methyl aminolaevulinate (MAL)-PDT with 11/2 vs. 21/2 h of daylight exposure...

  12. Seasonality in trauma admissions - Are daylight and weather variables better predictors than general cyclic effects?

    Science.gov (United States)

    Røislien, Jo; Søvik, Signe; Eken, Torsten

    2018-01-01

    Trauma is a leading global cause of death, and predicting the burden of trauma admissions is vital for good planning of trauma care. Seasonality in trauma admissions has been found in several studies. Seasonal fluctuations in daylight hours, temperature and weather affect social and cultural practices but also individual neuroendocrine rhythms that may ultimately modify behaviour and potentially predispose to trauma. The aim of the present study was to explore to what extent the observed seasonality in daily trauma admissions could be explained by changes in daylight and weather variables throughout the year. Retrospective registry study on trauma admissions in the 10-year period 2001-2010 at Oslo University Hospital, Ullevål, Norway, where the amount of daylight varies from less than 6 hours to almost 19 hours per day throughout the year. Daily number of admissions was analysed by fitting non-linear Poisson time series regression models, simultaneously adjusting for several layers of temporal patterns, including a non-linear long-term trend and both seasonal and weekly cyclic effects. Five daylight and weather variables were explored, including hours of daylight and amount of precipitation. Models were compared using Akaike's Information Criterion (AIC). A regression model including daylight and weather variables significantly outperformed a traditional seasonality model in terms of AIC. A cyclic week effect was significant in all models. Daylight and weather variables are better predictors of seasonality in daily trauma admissions than mere information on day-of-year.

  13. Daylight saving time transitions and hospital treatments due to accidents or manic episodes

    Directory of Open Access Journals (Sweden)

    Lönnqvist Jouko

    2008-02-01

    Full Text Available Abstract Background Daylight saving time affects millions of people annually but its impacts are still widely unknown. Sleep deprivation and the change of circadian rhythm can trigger mental illness and cause higher accident rates. Transitions into and out of daylight saving time changes the circadian rhythm and may cause sleep deprivation. Thus it seems plausible that the prevalence of accidents and/or manic episodes may be higher after transition into and out of daylight saving time. The aim of this study was to explore the effects of transitions into and out of daylight saving time on the incidence of accidents and manic episodes in the Finnish population during the years of 1987 to 2003. Methods The nationwide data were derived from the Finnish Hospital Discharge Register. From the register we obtained the information about the hospital-treated accidents and manic episodes during two weeks before and two weeks after the transitions in 1987–2003. Results The results were negative, as the transitions into or out of daylight saving time had no significant effect on the incidence of accidents or manic episodes. Conclusion One-hour transitions do not increase the incidence of manic episodes or accidents which require hospital treatment.

  14. Daylight saving time transitions and hospital treatments due to accidents or manic episodes

    Science.gov (United States)

    Lahti, Tuuli A; Haukka, Jari; Lönnqvist, Jouko; Partonen, Timo

    2008-01-01

    Background Daylight saving time affects millions of people annually but its impacts are still widely unknown. Sleep deprivation and the change of circadian rhythm can trigger mental illness and cause higher accident rates. Transitions into and out of daylight saving time changes the circadian rhythm and may cause sleep deprivation. Thus it seems plausible that the prevalence of accidents and/or manic episodes may be higher after transition into and out of daylight saving time. The aim of this study was to explore the effects of transitions into and out of daylight saving time on the incidence of accidents and manic episodes in the Finnish population during the years of 1987 to 2003. Methods The nationwide data were derived from the Finnish Hospital Discharge Register. From the register we obtained the information about the hospital-treated accidents and manic episodes during two weeks before and two weeks after the transitions in 1987–2003. Results The results were negative, as the transitions into or out of daylight saving time had no significant effect on the incidence of accidents or manic episodes. Conclusion One-hour transitions do not increase the incidence of manic episodes or accidents which require hospital treatment. PMID:18302734

  15. Daylight Adaptive Shading Using Parametric Camshaft Mechanism for SOHO in Jakarta

    Directory of Open Access Journals (Sweden)

    Sjarifudin Firza Utama

    2014-03-01

    Full Text Available This research analyzes SOHO (Small Office Home Office which can adjust to the need of visual comfort for the users through natural daylighting and also can be adapted to standard requirements of 14 creative industry workspace in Jakartas. The method of the research is by simulating the SOHO unit with variation of shading opening angles in order to adapt to each unit. Analysis done to every shading opening angle to get the appropriate daylight intensity level which support the work activities in every unit for the whole day. In order for the shading to be able to adapt to the changing daylight condition, previously developed parametric camshaft mechanism was used. The study found that the visual comfort for SOHO with creative industries workers in Jakarta can be achieve by varying the shading opening angles between 15-75°.

  16. Light Guide Collector Prototype: Laboratory Testing

    OpenAIRE

    Jitka - Mohelnikova; Stanislav Darula; Ayodeji Omishore; Petr Mohelnik; Denis Micek

    2017-01-01

    The article reviews the potential of light guide system equipped by a concentrator device capturing daylight applicable for illumination of building interiors and presents results of experiments on performance of its prototype. The main goal is focused on the comparison of traditional solutions and newly developed prototype of the light guide system and presents examination of its light transmission efficiency based on the laboratory experiments.

  17. Carbon dot-Au(i)Ag(0) assembly for the construction of an artificial light harvesting system.

    Science.gov (United States)

    Jana, Jayasmita; Aditya, Teresa; Pal, Tarasankar

    2018-03-06

    Artificial light harvesting systems (LHS) with inorganic counterparts are considered to be robust as well as mechanistically simple, where the system follows the donor-acceptor principle with an unchanged structural pattern. Plasmonic gold or silver nanoparticles are mostly chosen as inorganic counterparts to design artificial LHS. To capitalize on its electron accepting capability, Au(i) has been considered in this work for the synergistic stabilization of a system with intriguingly fluorescing silver(0) clusters produced in situ. Thus a stable fluorescent Au(i)Ag(0) assembly is generated with electron accepting capabilities. On the other hand, carbon dots have evolved as new fluorescent probes due to their unique physicochemical properties. Utilizing the simple electronic behavior of carbon dots, an electronic interaction between the fluorescent Au(i)Ag(0) and a carbon dot has been investigated for the construction of a new artificial light harvesting system. This coinage metal assembly allows surface energy transfer where it acts as an acceptor, while the carbon dot behaves as a good donor. The energy transfer efficiency has been calculated experimentally to be significant (81.3%) and the Au(i)Ag(0)-carbon dot assembly paves the way for efficient artificial LHS.

  18. Integrated optimization of temperature, CO2, screen use and artificial lighting in greenhouse crops

    DEFF Research Database (Denmark)

    Aaslyng, J.M.; Körner, O.; Andreassen, A.U.

    2005-01-01

    A leaf photosynthesis model is suggested for integrated optimization of temperature, CO2, screen use and artificial lighting in greenhouse crops. Three different approaches for the optimization are presented. First, results from greenhouse experiments with model based optimization are presented....... Second, a model-based analysis of a commercial grower's production possibility is shown. Third, results from a simulation of the effect of a new lighting strategy are demonstrated. The results demonstrate that it is possible to optimize plant production by using a model-based integrated optimization...... of temperature, CO2, and light in the greenhouse...

  19. Possibilities of Architectural Lighting to Create New Style

    Science.gov (United States)

    Chudinova, V. G.; Bokova, O. R.

    2017-11-01

    The article presents the argumentation of the provision on the style-forming potential of the lighting design the sphere of which is interpreted in a wide range of genres. The area of the intersection of form-building technological and artistic aspects lies in the field of ecology which includes not only energy saving, but also the well-being of the human and the society. The theory and practice of designing the night-time image of architectural ensembles, buildings and landscapes develops much slower than the implementation of light solutions in the advertising industry. In most cases, the possibilities of lighting design are used only in the field of decorative lighting despite their huge aesthetic potential and rapidly improving technologies. The request for innovation and uniqueness usually arises on the basis of image and political ambitions of large corporations or for the positioning of powerful brands. The success of such projects becomes a driver for both creation and promotion of innovative solutions. However, in a broader scientific sense, not only the design of artificial light systems but also the optimization of the daylight usage falls into the sphere lighting design. The need for the new methods of architectural shaping is dictated by the need to introduce in the building of resource-saving lighting technologies, ecological infrastructure including alternative energy sources. The article gives the examples of different lighting design genres supplemented with illustrations. The conclusions concern the prospective directions and tasks of scientific research in the field of lighting design.

  20. Variation of outdoor illumination as a function of solar elevation and light pollution.

    Science.gov (United States)

    Spitschan, Manuel; Aguirre, Geoffrey K; Brainard, David H; Sweeney, Alison M

    2016-06-07

    The illumination of the environment undergoes both intensity and spectral changes during the 24 h cycle of a day. Daylight spectral power distributions are well described by low-dimensional models such as the CIE (Commission Internationale de l'Éclairage) daylight model, but the performance of this model in non-daylight regimes is not characterised. We measured downwelling spectral irradiance across multiple days in two locations in North America: One rural location (Cherry Springs State Park, PA) with minimal anthropogenic light sources, and one city location (Philadelphia, PA). We characterise the spectral, intensity and colour changes and extend the existing CIE model for daylight to capture twilight components and the spectrum of the night sky.

  1. Dynamic lighting design

    DEFF Research Database (Denmark)

    Linnebjerg, Sofie

    [Berson et al., 2002] become apparent, that light, beside serving a purpose of enabling visual orientation, also are influencing the internal body clock, affecting sleep-wake cycle, immune responses, appetite, behaviour, mood, alertness and attention - depending on the duration, timing and quality...... of light [Schlangen, 2014]. But, as humans spend more than 90 % of the time inside a build environment [Klepeis et al., 2001] and the daylight intake in our buildings is not always optimal to meet the needs for dynamic light [Hansen et al., 2017], this research project points to the importance...

  2. THE EFFECT OF BUILDING FAÇADE MODEL ON LIGHT DISTRIBUTION (CASE STUDY: MENARA PHINISI BUILDING OF UNM

    Directory of Open Access Journals (Sweden)

    Nurul Jamala

    2017-12-01

    Full Text Available Global warming issues influence the temperature of the earth surface. It is an impact on energy consumption, especially in buildings. Utilization of daylight is one of the factors that need to be considered, in order to minimize energy consumption as a source of artificial lighting. This study analyzed the distribution of light on the Menara Phinisi building of Makassar State University. Quantitative research method that is to describe the data of simulation in Autodesk Ecotect program. The research objective was to determine the effect of the building facade model on the value of illumination inside the building. Results of the study concluded that the decrease percentage of the distribution of light on the building facade using and not using the facade is 3,16% or 236 lux. Distribution of light in horizontal and diagonal facade models differ in the amount of 2,5%. Design analysis of the building serves as a guide for analyzing the influence of the building facade model so that it can create energy efficient buildings.

  3. Teaching Science: Beats the Daylight Out of Me.

    Science.gov (United States)

    Leyden, Michael B.

    1995-01-01

    Presents activities for observing, measuring, collecting, and graphing data about times of sunrise and sunset to teach an understanding about arrival of Daylight Savings Time in April. Also discusses seasonal affective disorder (SAD). (TM)

  4. Overheating and Daylighting; Assessment Tool in Early Design of London’s High-Rise Residential Buildings

    Directory of Open Access Journals (Sweden)

    Bachir Nebia

    2017-08-01

    Full Text Available High-rise residential buildings in dense cities, such as London, are a common response to housing shortage. The apartments in these buildings may experience different levels of thermal and visual comfort, depending on their orientation and floor level. This paper aims to develop simplified tools to predict internal temperatures and daylighting levels, and propose a tool to quickly assess overheating risk and daylight performance in London’s high-rise residential buildings. Single- and double-sided apartments in a high-rise building were compared, and the impact of their floor level, glazing ratio, thermal mass, ventilation strategy and orientation was investigated. Using Integrated Environmental Solutions Virtual Environment (IES VE, temperature and daylight factor results of each design variable were used to develop early design tools to predict and assess overheating risks and daylighting levels. The results indicate that apartments that are more exposed to solar radiations, through either orientation or floor level, are more susceptible to overheat in the summer while exceeding the daylighting recommendations. Different design strategies at different levels and orientations are subsequently discussed.

  5. Energy-efficient window systems. Effects on energy use and daylight in buildings

    Energy Technology Data Exchange (ETDEWEB)

    Buelow-Huebe, H.

    2001-11-01

    This thesis deals with energy-efficient windows in Swedish buildings. Parametric studies were performed in the dynamic energy simulation tool Derob-LTH in order to study the effects of window choices on energy use and indoor climate for both residential and office buildings. A steady-state program was used to evaluate two years of measurements of energy use and indoor temperatures of an energy-efficient row-house. Two behavioural studies regarding (1) daylight transmittance, view and room perception using super-insulated windows and (2) the satisfaction with the daylight environment and the use of shading devices in response to daylight/sunlight were conducted in full-scale laboratory environments exposed to the natural climate. Results show that as the energy-efficiency of buildings increase, window U-values must decrease in order not to increase the annual heating demand, since the heating season is shortened, and useful solar gains become smaller. For single-family houses with a window-to-floor area ratio of 15 % and insulated according the current Swedish building code, the U-values should thus on average be lower than 1.0 W/m{sup 2}K. For houses insulated according to 1960s standard, the U-value may on average be 1.6 W/m{sup 2}K. For colder climates (northern Sweden), the U-values should be somewhat lower, while slightly higher U-values can be tolerated in milder climates of south Sweden. Thermal comfort during winter is improved for energy-efficient windows. However, overheating problems exist for both super-insulated houses and highly glazed office buildings showing a need for very low U-values in combination with low g-values. Daylight experiments indicate that the use of two low-emittance coatings tints the transmitted daylight enough to be appreciated, and colours may be perceived as more drab and rooms more enclosed. A compromise between energy-efficiency and daylighting may be needed, and it is suggested that only one coating be used except when very

  6. Light Guide Collector Prototype: Laboratory Testing

    Directory of Open Access Journals (Sweden)

    Jitka - Mohelnikova

    2017-12-01

    Full Text Available The article reviews the potential of light guide system equipped by a concentrator device capturing daylight applicable for illumination of building interiors and presents results of experiments on performance of its prototype. The main goal is focused on the comparison of traditional solutions and newly developed prototype of the light guide system and presents examination of its light transmission efficiency based on the laboratory experiments.

  7. Influence of daylight on the fate of silver and zinc oxide nanoparticles in natural aquatic environments

    International Nuclear Information System (INIS)

    Odzak, Niksa; Kistler, David; Sigg, Laura

    2017-01-01

    Nanoparticles, such as silver (Ag-NP) and zinc oxide (ZnO-NP), are increasingly used in many consumer products. These nanoparticles (NPs) will likely be exposed to the aquatic environment (rain, river, lake water) and to light (visible and UV) in the products where they are applied, or after those products are discharged. Dissolution of Ag-NP and ZnO-NP is an important process because the dissolved Ag + and Zn 2+ are readily available and toxic for aquatic organisms. The objective of this study was to investigate the role of daylight (UV and visible) for the fate of engineered Ag-NP and ZnO-NPs in different types of natural waters. Ag-NP and ZnO-NP were exposed to rainwater, river Rhine, and lake waters (Greifen, Lucerne, Cristallina, Gruère) under different light conditions (no light, UV 300–400 nm and visible light 400–700 nm) for up to 8 days. Stronger agglomeration of Ag-NP was observed in the waters with higher ionic strength in comparison to those with lower ionic strength. Visible light tended to increase the dissolution of Ag-NP under most natural water conditions in comparison to dark conditions, whereas UV-light led to decreased dissolved Ag + after longer exposure time. These effects illustrate the dynamic interactions of Ag-NP with light, which may lead both to increased oxidation and to increased reduction of Ag + by organic compounds under UV-light. In the case of ZnO-NP, agglomeration occurred at higher ionic strength, but the effects of pH were predominant for dissolution, which occurred up to concentrations close to the solubility limit of ZnO(s) at pH around 8.2 and to nearly complete dissolution of ZnO-NP at lower pH (pH 4.8–6.5), with both visible and UV-light facilitating dissolution. This study thus shows that light conditions play an important role in the dissolution processes of nanoparticles. - Highlights: • Effects of visible and UV-light on dissolution of silver and zinc oxide nanoparticles were examined. • Natural waters

  8. Continuous daylight in the high-Arctic summer supports high plankton respiration rates compared to those supported in the dark

    KAUST Repository

    Mesa, Elena

    2017-04-21

    Plankton respiration rate is a major component of global CO2 production and is forecasted to increase rapidly in the Arctic with warming. Yet, existing assessments in the Arctic evaluated plankton respiration in the dark. Evidence that plankton respiration may be stimulated in the light is particularly relevant for the high Arctic where plankton communities experience continuous daylight in spring and summer. Here we demonstrate that plankton community respiration evaluated under the continuous daylight conditions present in situ, tends to be higher than that evaluated in the dark. The ratio between community respiration measured in the light (Rlight) and in the dark (Rdark) increased as the 2/3 power of Rlight so that the Rlight:Rdark ratio increased from an average value of 1.37 at the median Rlight measured here (3.62 µmol O2 L-1 d-1) to an average value of 17.56 at the highest Rlight measured here (15.8 µmol O2 L-1 d-1). The role of respiratory processes as a source of CO2 in the Arctic has, therefore, been underestimated and is far more important than previously believed, particularly in the late spring, with 24 h photoperiods, when community respiration rates are highest.

  9. Artificial skin and patient simulator comprising the artificial skin

    NARCIS (Netherlands)

    2011-01-01

    The invention relates to an artificial skin (10, 12, 14), and relates to a patient simulator (100) comprising the artificial skin. The artificial skin is a layered structure comprising a translucent cover layer (20) configured for imitating human or animal skin, and comprising a light emitting layer

  10. Activity Patterns during Food Provisioning Are Affected by Artificial Light in Free Living Great Tits (Parus major)

    NARCIS (Netherlands)

    Titulaer, M.; Spoelstra, K.; Lange, C.Y.M.J.G.; Visser, M.E.

    2012-01-01

    Artificial light may have severe ecological consequences but there is limited experimental work to assess these consequences. We carried out an experimental study on a wild population of great tits (Parus major) to assess the impact of light pollution on daily activity patterns during the chick

  11. Daylight and health: A review of the evidence and consequences for the built environment

    NARCIS (Netherlands)

    M.P.J. Aarts; Joost van Hoof; M.B.C. Aries

    2015-01-01

    Daylight has been associated with multiple health advantages. Some of these claims are associations, hypotheses or beliefs. This review presents an overview of a scientific literature search on the proven effects of daylight exposure on human health. Studies were identified with a search strategy

  12. Performance of integrated systems of automated roller shade systems and daylight responsive dimming systems

    Energy Technology Data Exchange (ETDEWEB)

    Park, Byoung-Chul; Choi, An-Seop; Jeong, Jae-Weon [Department of Architectural Engineering, Sejong University, Kunja-Dong, Kwangjin-Gu, Seoul (Korea, Republic of); Lee, Eleanor S. [Building Technologies Department, Lawrence Berkeley National Laboratory, Berkeley, CA (United States)

    2011-03-15

    Daylight responsive dimming systems have been used in few buildings to date because they require improvements to improve reliability. The key underlying factor contributing to poor performance is the variability of the ratio of the photosensor signal to daylight workplane illuminance in accordance with sun position, sky condition, and fenestration condition. Therefore, this paper describes the integrated systems between automated roller shade systems and daylight responsive dimming systems with an improved closed-loop proportional control algorithm, and the relative performance of the integrated systems and single systems. The concept of the improved closed-loop proportional control algorithm for the integrated systems is to predict the varying correlation of photosensor signal to daylight workplane illuminance according to roller shade height and sky conditions for improvement of the system accuracy. In this study, the performance of the integrated systems with two improved closed-loop proportional control algorithms was compared with that of the current (modified) closed-loop proportional control algorithm. In the results, the average maintenance percentage and the average discrepancies of the target illuminance, as well as the average time under 90% of target illuminance for the integrated systems significantly improved in comparison with the current closed-loop proportional control algorithm for daylight responsive dimming systems as a single system. (author)

  13. [Effects of low-light stress on photosynthetic characteristics of Paris polyphylla var. chinensis in artificial domestication cultivation].

    Science.gov (United States)

    Zheng, Shun-lin; Tian, Meng-liang; Liu, Jin-liang; Zhao, Ting-ting; Zhang, Zhong

    2014-09-01

    To decide on the optimum artificial domestication cultivation light environment for Paris polyphylla var. chinensis through investigating the effect of light intensity on leaf's gas exchange parameters, photosynthetic parameters, light saturation point and compensation point of Paris polyphylla var. chinensis. Different low-light stress gradients' effect on the growth of Paris polyphylla var. chinensis was compared with no low-light stress treatment through calculating leaf's gas exchange parameters, photosynthetic parameters, light saturation point and compensation point, and then all these parameters were statistically analyzed. Light intensity had significant influence on the photosynthetic characteristics of Paris polyphylla var. chinensis. With the strengthening of the low-light stress, chlorophyll content, gas exchange parameters, photosynthetic parameters P., AQY and light saturation point all gradually increased at first, and then decreased. However, both photosynthetic parameters Rd and light compensation point firstly decreased and then rose again. These results showed that too strong or too weak light intensity affected the optimization of photosynthetic parameters of Paris polyphylla var. chinensis. The optimal illuminance for each parameter was not completely same, but they could all reach a relative ideal state when the shading ranges between 40% and 60%. However, photosynthetic parameters deteriorated rapidly when the shading surpass 80%. For artificially cultivating Paris polyphylla var. chinensis in Baoxing,Sichuan or the similar ecological region, shading 40%-60% is the optimal light environment, which can enhance the photosynthesis of Paris polyphylla var. chinensis and promote the accumulation of photosynthetic products.

  14. Performance of Anidolic Daylighting Systems in tropical climates - Parametric studies for identification of main influencing factors

    Energy Technology Data Exchange (ETDEWEB)

    Linhart, Friedrich; Scartezzini, Jean-Louis [Solar Energy and Building Physics Laboratory (LESO-PB), Swiss Federal Institute of Technology in Lausanne (EPFL), 1015 Lausanne (Switzerland); Wittkopf, Stephen K. [School of Design and Environment, Department of Architecture, National University of Singapore, 4 Architecture Drive, Singapore 117566 (Singapore)

    2010-07-15

    Making daylight more available in buildings is highly desirable, not only for reasons of energy-efficiency, but also for improvement of occupants' health and well-being. Core-daylighting, that is daylight provision in areas situated at considerable distances from facades and windows, is currently one of the main challenges in sustainable building design. Anidolic Daylighting Systems (ADSs) are one very promising technology in the field of core-daylighting, but commercial solutions that are not only well-performing but also financially competitive are not yet widely available. This article presents results of parametric studies on Anidolic Integrated Ceilings (AICs), a special type of ADS, for identification of main influencing factors. The article describes a reliable method for simulating ADS and AIC performance under given sky conditions. Various simulation results for the example location Singapore are discussed in detail, it is concluded that the main influencing factors are coating material, system dimensions and external obstruction, and those influencing factors' potential impacts are quantified. It is shown that AIC overall efficiencies can reach up to almost 50% in Singapore. The essentially new results presented in this article can be of great help to architects, engineers and scientists in the future, when it comes to precisely dimensioning ADS for various buildings and daylight conditions. (author)

  15. Singapore's Zero-Energy Building's daylight monitoring system

    Energy Technology Data Exchange (ETDEWEB)

    Grobe, Lars; Wittkopf, Stephen; Pandey, Anupama Rana; Xiaoming, Yang; Seng, Ang Kian; Scartezzini, Jean-Louis; Selkowitz, Stephen

    2010-02-28

    A setup to monitor the daylighting performance of different glazing types in Singapore is presented. The glazing is installed in the facade of four dedicated testing chambers in BCAA's Zero Energy Building in Singapore. These test rooms are equipped with sensors that both record illuminances on the work plane, and luminances as seen by occupants. The physical and logical design of the monitoring system is presented. Criteria to assess the daylighting performance are introduced, and initial results of the work in progress are presented.

  16. Seasonality in trauma admissions – Are daylight and weather variables better predictors than general cyclic effects?

    Science.gov (United States)

    Søvik, Signe; Eken, Torsten

    2018-01-01

    Background Trauma is a leading global cause of death, and predicting the burden of trauma admissions is vital for good planning of trauma care. Seasonality in trauma admissions has been found in several studies. Seasonal fluctuations in daylight hours, temperature and weather affect social and cultural practices but also individual neuroendocrine rhythms that may ultimately modify behaviour and potentially predispose to trauma. The aim of the present study was to explore to what extent the observed seasonality in daily trauma admissions could be explained by changes in daylight and weather variables throughout the year. Methods Retrospective registry study on trauma admissions in the 10-year period 2001–2010 at Oslo University Hospital, Ullevål, Norway, where the amount of daylight varies from less than 6 hours to almost 19 hours per day throughout the year. Daily number of admissions was analysed by fitting non-linear Poisson time series regression models, simultaneously adjusting for several layers of temporal patterns, including a non-linear long-term trend and both seasonal and weekly cyclic effects. Five daylight and weather variables were explored, including hours of daylight and amount of precipitation. Models were compared using Akaike’s Information Criterion (AIC). Results A regression model including daylight and weather variables significantly outperformed a traditional seasonality model in terms of AIC. A cyclic week effect was significant in all models. Conclusion Daylight and weather variables are better predictors of seasonality in daily trauma admissions than mere information on day-of-year. PMID:29425210

  17. Evening daylight may cause adolescents to sleep less in spring than in winter

    Science.gov (United States)

    Figueiro, Mariana G.; Rea, Mark S.

    2012-01-01

    Sleep restriction commonly experienced by adolescents can stem from greater sleep pressure by the homeostatic processes and from phase delays of the circadian system. With regard to the latter potential cause, we hypothesized that because there is more natural evening light during the spring than winter, a sample of adolescent students would be more phase delayed in spring than in winter, would have later sleep onset times and, because of fixed school schedules, would have shorter sleep durations. Sixteen eighth-grade subjects were recruited for the study. We collected sleep logs and saliva samples to determine their dim light melatonin onset (DLMO), a well-established circadian marker. Actual circadian light exposures experienced by a subset of twelve subjects over the course of seven days in winter and in spring using a personal, head-worn, circadian light measurement device are also reported here. Results showed that this sample of adolescents was exposed to significantly more circadian light in spring than in winter, especially in the evening hours when light exposure would likely delay circadian phase. Consistent with the light data, DLMO and sleep onset times were significantly more delayed, and sleep durations were significantly shorter in spring than in winter. The present ecological study of light, circadian phase, and self-reported sleep suggests that greater access to evening daylight in the spring may lead to sleep restriction in adolescents while attending school. Therefore, lighting schemes that reduce evening light in the spring may encourage longer sleep times in adolescents. PMID:20653452

  18. Lawrence Berkeley Laboratory/University of California lighting program overview

    Energy Technology Data Exchange (ETDEWEB)

    Berman, S.

    1981-12-01

    The objective of the Lighting Program is to assist and work in concert with the lighting community (composed of manufacturers, designers, and users) to achieve a more efficient lighting economy. To implement its objectives, the Lighting Program has been divided into three major categories: technical engineering, buildings applications, and human impacts (impacts on health and vision). The technical program aims to undertake research and development projects that are both long-range and high-risk and which the lighting industry has little interest in pursuing on its own, but from which significant benefits could accrue to both the public and the industry. The building applications program studies the effects that introducing daylighting in commercial buildings has on lighting and cooling electrical energy requirements as well as on peak demand. This program also examines optimization strategies for integrating energy-efficient design, lighting hardware, daylighting, and overall building energy requirements. The impacts program examines relationships between the user and the physical lighting environment, in particular how new energy-efficient technologies relate to human productivity and health. These efforts are interdisciplinary, involving engineering, optometry, and medicine. The program facilities are described and the personnel in the program is identified.

  19. Illumination of interior spaces by bended hollow light guides: Application of the theoretical light propagation method

    Energy Technology Data Exchange (ETDEWEB)

    Darula, Stanislav; Kocifaj, Miroslav; Kittler, Richard [ICA, Slovak Academy of Sciences, Bratislava (Slovakia); Kundracik, Frantisek [Department of Experimental Physics, FMPI, Comenius University, Bratislava (Slovakia)

    2010-12-15

    To ensure comfort and healthy conditions in interior spaces the thermal, acoustics and daylight factors of the environment have to be considered in the building design. Due to effective energy performance in buildings the new technology and applications also in daylight engineering are sought such as tubular light guides. These allow the transport of natural light into the building core reducing energy consumption. A lot of installations with various geometrical and optical properties can be applied in real buildings. The simplest set of tubular light guide consists of a transparent cupola, direct tube with high reflected inner surface and a ceiling cover or diffuser redistributing light into the interior. Such vertical tubular guide is often used on flat roofs. When the roof construction is inclined a bend in the light guide system has to be installed. In this case the cupola is set on the sloped roof which collects sunlight and skylight from the seen part of the sky hemisphere as well as that reflected from the ground and opposite facades. In comparison with the vertical tube some additional light losses and distortions of the propagated light have to be expected in bended tubular light guides. Recently the theoretical model of light propagation was already published and its applications are presented in this study solving illuminance distributions on the ceiling cover interface and further illuminance distribution on the working plane in the interior. (author)

  20. The health risks associated with energy efficient fluorescent, LEDs, and artificial lighting

    Science.gov (United States)

    Panahi, Allen

    2014-09-01

    With the phasing out of incandescent lamps in many countries, the introduction of new LED based light sources and luminaries sometimes raise the question of whether the spectral characteristics of the LED and other energy savings Fluorescent lights including the popular CFLs are suitable to replace the traditional incandescent lamps. These concerns are sometimes raised particularly for radiation emissions in the UV and Blue parts of the spectrum. This paper aims to address such concerns for the common `white light' sources typically used in household and other general lighting used in the work place. Recent studies have shown that women working the night shift have an increased probability of developing breast cancer. We like to report on the findings of many studies done by medical professionals, in particular the recent announcement of AMA in the US and many studies conducted in the UK, as well as the European community to increase public awareness on the long term health risks of the optical and opto-biological effects on the human health caused by artificial lighting.

  1. Theoretical solution for light transmission of a bended hollow light guide

    Energy Technology Data Exchange (ETDEWEB)

    Kocifaj, Miroslav; Darula, Stanislav; Kittler, Richard [ICA, Slovak Academy of Sciences, 9, Dubravska Road, 845 03 Bratislava (Slovakia); Kundracik, Frantisek [Department of Experimental Physics, FMPI, Comenius University, Mlynska dolina, 842 48 Bratislava (Slovakia)

    2010-08-15

    Hollow light guides with very high reflective inner surfaces are novel daylight systems that collect sunlight and skylight available on the roof of buildings transporting it into deep or windowless interiors in building cores. Thus the better utilization of daylight can result in energy savings and wellbeing in these enclosed indoor spaces. An analytical complex solution of a straight tube system was solved in the HOLIGILM method with a user-friendly tool available on the http://www.holigilm.info. An even more difficult light flow transport is to be determined in bended tubes usually placed on sloped roofs where a bend is necessary to adjust the vertical pass through the ceilings. This paper presents the theoretical derivation of the model with its graphical representation and coordinate system respecting backward ray-tracing bend distortions. To imagine the resulting illuminance on the horizontal plane element in the interior, the virtual ray (i.e. luminance in an elementary solid angle) has to pass the ceiling diffuser interface, the inner mirror like tube with a bend, through a roof cupola attachment to the element of the sky and sun light source. Due to this complexity and the lengthy derivation and explanations more practical applications will be published later in a separate contribution. (author)

  2. Energy Savings by Using Daylight for Basic Urban Shapes : With a Case Study of Three Different Street Types

    OpenAIRE

    Sundborg, Bengt

    2016-01-01

    During winter the sun is in short supply. But research at KTH shows that solar radiation can be facilitated while energy consumption for lighting is reduced. This provided that the buildings are appropriately designed. But, unfortunately, the sunlight is often not taken into account and the results are the opposite. The energy savings depend on good town planning where the daylight is accessible for longer periods of time during the day, both indoors and outdoors. Then, the periods of use for...

  3. Artificial light at night affects sleep behaviour differently in two closely related songbird species.

    Science.gov (United States)

    Sun, Jiachen; Raap, Thomas; Pinxten, Rianne; Eens, Marcel

    2017-12-01

    Artificial light at night (ALAN) or light pollution is an increasing and worldwide problem. There is growing concern that because of the disruption of natural light cycles, ALAN may pose serious risks for wildlife. While ALAN has been shown to affect many aspects of animal behaviour and physiology, few studies have experimentally studied whether individuals of different species in the wild respond differently to ALAN. Here, we investigated the effect of ALAN on sleep behaviour in two closely related songbird species inhabiting the same study area and roosting/breeding in similar nest boxes. We experimentally exposed free-living great tits (Parus major) and blue tits (Cyanistes caeruleus) to artificial light inside their nest boxes and observed changes in their sleep behaviour compared to the previous night when the nest boxes were dark. In line with previous studies, sleep behaviour of both species did not differ under dark conditions. ALAN disrupted sleep in both great and blue tits. However, compared to blue tits, great tits showed more pronounced effects and more aspects of sleep were affected. Light exposed great tits entered the nest boxes and fell asleep later, woke up and exited the nest boxes earlier, and the total sleep amount and sleep percentage were reduced. By contrast, these changes in sleep behaviour were not found in light exposed blue tits. Our field experiment, using exactly the same light manipulation in both species, provides direct evidence that two closely related species respond differently to ALAN, while their sleep behaviour under dark conditions was similar. Our research suggests that findings for one species cannot necessarily be generalised to other species, even closely-related species. Furthermore, species-specific effects could have implications for community dynamics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Determining daylight and view preferences from the use of blinds in apartments

    DEFF Research Database (Denmark)

    Petersen, Mads Dines

    2015-01-01

    preferences have significant influence on the daylight level and view as well as possible impact on the building’s energy consumption. Therefore, it is important to conduct further studies in the area in order to be able to design solutions that supports the user preferences better and through that improves...... for the inhabitants’ health and well-being, as well as the energy consumption. Present research is an important contribution, because of the increased knowledge about daylights impact on health and well-being as well as daylights impact on the energy consumption in our buildings. However, it is often seen...... that curtains or blinds, often close off new apartment buildings with large glass areas in dense urban context. Such observations indicate that there can be a discrepancy between the intentions of the design team or architect and the perception of the user. The paper presents the results of observations...

  5. An analysis of energy-efficient light fittings and lighting controls

    International Nuclear Information System (INIS)

    Li, Danny H.W.; Cheung, K.L.; Wong, S.L.; Lam, Tony N.T.

    2010-01-01

    Electric lighting is one of the major energy consuming items in many non-domestic buildings. Using appropriate energy-efficient light fittings with dimming controls and proper daylighting schemes can help reduce the electrical demand and contribute to visual comfort and green building development. This paper presents a study on the energy and lighting performances for energy-efficient fluorescent lamps associated with electronic ballasts and high frequency photoelectric dimming controls installed in a school building. Electricity expenditures and indoor illuminance levels for a workshop and a classroom employing high frequency dimming controls were analyzed. Simple prediction methods were used to illustrate the lighting savings. The findings provide the operational and performance information, which would be applicable to other spaces with similar building layouts and lighting schemes.

  6. Does Daylight Savings Time encourage physical activity?

    Science.gov (United States)

    Zick, Cathleen D

    2014-07-01

    Extending Daylight Savings Time (DST) has been identified as a policy intervention that may encourage physical activity. However, there has been little research on the question of if DST encourages adults to be more physically active. Data from residents of Arizona, Colorado, New Mexico, and Utah ages 18-64 who participated in the 2003-2009 American Time Use Survey are used to assess whether DST is associated with increased time spent in moderate-to-vigorous physical activity (MVPA). The analysis capitalizes on the natural experiment created because Arizona does not observe DST. Both bivariate and multivariate analyses indicate that shifting 1 hour of daylight from morning to evening does not impact MVPA of Americans living in the southwest. While DST may affect the choices people make about the timing and location of their sports/recreational activities, the potential for DST to serve as a broad-based intervention that encourages greater sports/recreation participation is not supported by this analysis. Whether this null effect would persist in other climate situations is an open question.

  7. Affordable and personalized lighting using inverse modeling and virtual sensors

    Science.gov (United States)

    Basu, Chandrayee; Chen, Benjamin; Richards, Jacob; Dhinakaran, Aparna; Agogino, Alice; Martin, Rodney

    2014-03-01

    Wireless sensor networks (WSN) have great potential to enable personalized intelligent lighting systems while reducing building energy use by 50%-70%. As a result WSN systems are being increasingly integrated in state-ofart intelligent lighting systems. In the future these systems will enable participation of lighting loads as ancillary services. However, such systems can be expensive to install and lack the plug-and-play quality necessary for user-friendly commissioning. In this paper we present an integrated system of wireless sensor platforms and modeling software to enable affordable and user-friendly intelligent lighting. It requires ⇠ 60% fewer sensor deployments compared to current commercial systems. Reduction in sensor deployments has been achieved by optimally replacing the actual photo-sensors with real-time discrete predictive inverse models. Spatially sparse and clustered sub-hourly photo-sensor data captured by the WSN platforms are used to develop and validate a piece-wise linear regression of indoor light distribution. This deterministic data-driven model accounts for sky conditions and solar position. The optimal placement of photo-sensors is performed iteratively to achieve the best predictability of the light field desired for indoor lighting control. Using two weeks of daylight and artificial light training data acquired at the Sustainability Base at NASA Ames, the model was able to predict the light level at seven monitored workstations with 80%-95% accuracy. We estimate that 10% adoption of this intelligent wireless sensor system in commercial buildings could save 0.2-0.25 quads BTU of energy nationwide.

  8. Extension of Light-Harvesting Ability of Photosynthetic Light-Harvesting Complex 2 (LH2) through Ultrafast Energy Transfer from Covalently Attached Artificial Chromophores.

    Science.gov (United States)

    Yoneda, Yusuke; Noji, Tomoyasu; Katayama, Tetsuro; Mizutani, Naoto; Komori, Daisuke; Nango, Mamoru; Miyasaka, Hiroshi; Itoh, Shigeru; Nagasawa, Yutaka; Dewa, Takehisa

    2015-10-14

    Introducing appropriate artificial components into natural biological systems could enrich the original functionality. To expand the available wavelength range of photosynthetic bacterial light-harvesting complex 2 (LH2 from Rhodopseudomonas acidophila 10050), artificial fluorescent dye (Alexa Fluor 647: A647) was covalently attached to N- and C-terminal Lys residues in LH2 α-polypeptides with a molar ratio of A647/LH2 ≃ 9/1. Fluorescence and transient absorption spectroscopies revealed that intracomplex energy transfer from A647 to intrinsic chromophores of LH2 (B850) occurs in a multiexponential manner, with time constants varying from 440 fs to 23 ps through direct and B800-mediated indirect pathways. Kinetic analyses suggested that B800 chromophores mediate faster energy transfer, and the mechanism was interpretable in terms of Förster theory. This study demonstrates that a simple attachment of external chromophores with a flexible linkage can enhance the light harvesting activity of LH2 without affecting inherent functions of energy transfer, and can achieve energy transfer in the subpicosecond range. Addition of external chromophores, thus, represents a useful methodology for construction of advanced hybrid light-harvesting systems that afford solar energy in the broad spectrum.

  9. The Dynamics of Daylighting at a Residential College Building with the Internal Courtyard Arrangement

    Directory of Open Access Journals (Sweden)

    Adi Ainurzaman Jamaludin

    2015-11-01

    Full Text Available Dayasari residential college building was designed with the internal courtyard that allows for numerous implementations of bioclimatic design strategies, especially on daylighting. The field measurement was conducted at eight unoccupied student rooms, selected as samples to represent ten scenarios and orientations that concerned with the level of radiation and penetration of sunlight. This study reveals the contribution of the internal courtyard in the residential college which allows the daylight penetration at the corridor areas and interior of the rooms through the transom over the entrance door, up to ten hours daily. Different amounts of daylight were measured in specific room scenarios to suggest on the most comfortable indoor living space. The recorded mean value for indoor varied from 37 to 286 lux, while in the corridor area 192 to 3,848 lux. However, the use of the large overhangs over the windows, wall openings in the room and trees with large canopy in the landscape setting should critically justify when the adequacy of daylight was drastically reduced in certain rooms.

  10. Fatal alcohol-related traffic crashes increase subsequent to changes to and from daylight savings time.

    Science.gov (United States)

    Hicks, G J; Davis, J W; Hicks, R A

    1998-06-01

    On the hypothesis that sleepiness and alcohol interact to increase the risk of alcohol-related traffic fatalities, the percentages of alcohol-related fatal traffic crashes were assessed for the entire state of New Mexico for the years 1989-1992, for each of the seven days that preceded the changes to and from Daylight Savings Time and for each of the 14 days which followed the changes to and from Daylight Savings Time. Consistent with our hypothesis the percentage of alcohol-related fatal crashes increased significantly during the first seven days after these changes in Daylight Savings Time.

  11. An Artificial Neural Network for Analyzing Overall Uniformity in Outdoor Lighting Systems

    Directory of Open Access Journals (Sweden)

    Antonio del Corte-Valiente

    2017-02-01

    Full Text Available Street lighting installations are an essential service for modern life due to their capability of creating a welcoming feeling at nighttime. Nevertheless, several studies have highlighted that it is possible to improve the quality of the light significantly improving the uniformity of the illuminance. The main difficulty arises when trying to improve some of the installation’s characteristics based only on statistical analysis of the light distribution. This paper presents a new algorithm that is able to obtain the overall illuminance uniformity in order to improve this sort of installations. To develop this algorithm it was necessary to perform a detailed study of all the elements which are part of street lighting installations. Because classification is one of the most important tasks in the application areas of artificial neural networks, we compared the performances of six types of training algorithms in a feed forward neural network for analyzing the overall uniformity in outdoor lighting systems. We found that the best algorithm that minimizes the error is “Levenberg-Marquardt back-propagation”, which approximates the desired output of the training pattern. By means of this kind of algorithm, it is possible to help to lighting professionals optimize the quality of street lighting installations.

  12. Natural light illumination system.

    Science.gov (United States)

    Whang, Allen Jong-Woei; Chen, Yi-Yung; Yang, Shu-Hua; Pan, Po-Hsuan; Chou, Kao-Hsu; Lee, Yu-Chi; Lee, Zong-Yi; Chen, Chi-An; Chen, Cheng-Nan

    2010-12-10

    In recent years, green energy has undergone a lot of development and has been the subject of many applications. Many research studies have focused on illumination with sunlight as a means of saving energy and creating healthy lighting. Natural light illumination systems have collecting, transmitting, and lighting elements. Today, most daylight collectors use dynamic concentrators; these include Sun tracking systems. However, this design is too expensive to be cost effective. To create a low-cost collector that can be easily installed on a large building, we have designed a static concentrator, which is prismatic and cascadable, to collect sunlight for indoor illumination. The transmission component uses a large number of optical fibers. Because optical fibers are expensive, this means that most of the cost for the system will be related to transmission. In this paper, we also use a prismatic structure to design an optical coupler for coupling n to 1. With the n-to-1 coupler, the number of optical fibers necessary can be greatly reduced. Although this new natural light illumination system can effectively guide collected sunlight and send it to the basement or to other indoor places for healthy lighting, previously there has been no way to manage the collected sunlight when lighting was not desired. To solve this problem, we have designed an optical switch and a beam splitter to control and separate the transmitted light. When replacing traditional sources, the lighting should have similar characteristics, such as intensity distribution and geometric parameters, to those of traditional artificial sources. We have designed, simulated, and optimized an illumination lightpipe with a dot pattern to redistribute the collected sunlight from the natural light illumination system such that it equals the qualities of a traditional lighting system. We also provide an active lighting module that provides lighting from the natural light illumination system or LED auxiliary

  13. Simulating the operation of photosensor-based lighting controls

    International Nuclear Information System (INIS)

    Ehrlich, Charles; Papamichael, Konstantinos; Lai, Judy; Revzan, Kenneth

    2001-01-01

    Energy savings from the use of daylighting in commercial buildings are realized through implementation of photoelectric lighting controls that dim electric lights when sufficient daylight is available to provide adequate workplane illumination. The dimming level of electric lighting is based on the signal of a photosensor. Current simulation approaches for such systems are based on the questionable assumption that the signal of the photosensor is proportional to the task illuminance. This paper presents a method that simulates the performance of photosensor controls considering the acceptance angle, angular sensitivity, placement of the photosensor within a space, and color correction filter. The method is based on the multiplication of two fisheye images: one generated from the angular sensitivity of the photosensor and the other from a 180- or 360-degree fisheye image of the space as ''seen'' by the photosensor. The paper includes a detailed description of the method and its implementation, example applications, and validation results based on comparison with measurements in an actual office space

  14. Light

    DEFF Research Database (Denmark)

    Prescott, N.B.; Kristensen, Helle Halkjær; Wathes, C.M.

    2004-01-01

    This chapter presents the effect of artificial light environments (light levels, colour, photoperiod and flicker) on the welfare of broilers in terms of vision, behaviour, lameness and mortality......This chapter presents the effect of artificial light environments (light levels, colour, photoperiod and flicker) on the welfare of broilers in terms of vision, behaviour, lameness and mortality...

  15. A study on the performance enhancement of low-temperature solar applications : Daylighting and Adsorption Desalination System

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yeong Min

    2011-02-15

    Thermal applications of solar energy are categorized by low, medium and high temperature. The present study has explored two major applications of solar energy widely researched and practiced these days. Of these, one deals with the utilization of solar energy for lighting in buildings, which is responsible for a great portion of electricity consumption, especially, for office and public buildings. Rapid improvements in lighting technology harnessing solar energy (daylight) have greatly contributed to radically reduce its consumption levels - and thereby reduce CO{sub 2} emissions and cost. The other case considered here for solar utilization is so-called solar desalination using adsorbents (silica gels). This technology utilizes a silica gel adsorbent (desiccant) as a medium between an evaporator and a condenser to reject and facilitate latent heat of vaporization. Vapour is adsorbed and desorbed between evaporation and condensation phases. 1. Daylighting simulation A lighting upgrade is an obvious step toward improving a building's energy consumption, which could be easily assessed by using computer simulations. The present study has carried out a series of computer simulations for a lightless space as well as an actual classroom (in Jeju National University) when sun pipe systems are installed. They were first modeled by ECOTECT before RADIANCE was called in to conduct lighting analysis. Simulations were performed for equinoxes and solstices when the sun is at its highest altitude, i.e. at noon (12 PM). A lightless space and classroom of the same dimensions revealed the effectiveness of sun pipe systems to improve indoor lighting conditions throughout the year. 2. Development of adsorption desalination system utilizing silica-gel Some major components of an adsorption desalination system were designed and fabricated to assess its desalination efficiency when packs of silica-gel were used at different operating conditions. The amount of fresh water yield was

  16. A study on the performance enhancement of low-temperature solar applications : Daylighting and Adsorption Desalination System

    International Nuclear Information System (INIS)

    Kim, Yeong Min

    2011-02-01

    Thermal applications of solar energy are categorized by low, medium and high temperature. The present study has explored two major applications of solar energy widely researched and practiced these days. Of these, one deals with the utilization of solar energy for lighting in buildings, which is responsible for a great portion of electricity consumption, especially, for office and public buildings. Rapid improvements in lighting technology harnessing solar energy (daylight) have greatly contributed to radically reduce its consumption levels - and thereby reduce CO 2 emissions and cost. The other case considered here for solar utilization is so-called solar desalination using adsorbents (silica gels). This technology utilizes a silica gel adsorbent (desiccant) as a medium between an evaporator and a condenser to reject and facilitate latent heat of vaporization. Vapour is adsorbed and desorbed between evaporation and condensation phases. 1. Daylighting simulation A lighting upgrade is an obvious step toward improving a building's energy consumption, which could be easily assessed by using computer simulations. The present study has carried out a series of computer simulations for a lightless space as well as an actual classroom (in Jeju National University) when sun pipe systems are installed. They were first modeled by ECOTECT before RADIANCE was called in to conduct lighting analysis. Simulations were performed for equinoxes and solstices when the sun is at its highest altitude, i.e. at noon (12 PM). A lightless space and classroom of the same dimensions revealed the effectiveness of sun pipe systems to improve indoor lighting conditions throughout the year. 2. Development of adsorption desalination system utilizing silica-gel Some major components of an adsorption desalination system were designed and fabricated to assess its desalination efficiency when packs of silica-gel were used at different operating conditions. The amount of fresh water yield was studied

  17. Artificial LED lighting enhances growth characteristics and total phenolic content of Ocimum basilicum, but variably affects transplant success

    NARCIS (Netherlands)

    Bantis, Filippos; Ouzounis, Theoharis; Radoglou, Kalliopi

    2016-01-01

    The morphological and phytochemical characteristics of two Ocimum basilicum cultivars (Lettuce Leaf, and Red Rubin-mountain Athos hybrid) under artificial lighting were investigated. Four LED light treatments [AP673L (high red and high red:far-red), G2 (high red and low red:far-red), AP67

  18. Daylight metrics and energy savings

    Energy Technology Data Exchange (ETDEWEB)

    Mardaljevic, John; Heschong, Lisa; Lee, Eleanor

    2009-12-31

    The drive towards sustainable, low-energy buildings has increased the need for simple, yet accurate methods to evaluate whether a daylit building meets minimum standards for energy and human comfort performance. Current metrics do not account for the temporal and spatial aspects of daylight, nor of occupants comfort or interventions. This paper reviews the historical basis of current compliance methods for achieving daylit buildings, proposes a technical basis for development of better metrics, and provides two case study examples to stimulate dialogue on how metrics can be applied in a practical, real-world context.

  19. Barriers and benefits: implications of artificial night-lighting for the distribution of common bats in Britain and Ireland

    Science.gov (United States)

    Mathews, Fiona; Roche, Niamh; Aughney, Tina; Jones, Nicholas; Day, Julie; Baker, James; Langton, Steve

    2015-01-01

    Artificial lighting is a particular problem for animals active at night. Approximately 69% of mammal species are nocturnal, and one-third of these are bats. Due to their extensive movements—both on a nightly basis to exploit ephemeral food supplies, and during migration between roosts—bats have an unusually high probability of encountering artificial light in the landscape. This paper reviews the impacts of lighting on bats and their prey, exploring the direct and indirect consequences of lighting intensity and spectral composition. In addition, new data from large-scale surveys involving more than 265 000 bat calls at more than 600 locations in two countries are presented, showing that prevalent street-lighting types are not generally linked with increased activity of common and widespread bat species. Such bats, which are important to ecosystem function, are generally considered ‘light-attracted’ and likely to benefit from the insect congregations that form at lights. Leisler's bat (Nyctalus leisleri) may be an exception, being more frequent in lit than dark transects. For common pipistrelle bats (Pipistrellus pipistrellus), lighting is negatively associated with their distribution on a landscape scale, but there may be local increases in habitats with good tree cover. Research is now needed on the impacts of sky glow and glare for bat navigation, and to explore the implications of lighting for habitat matrix permeability. PMID:25780236

  20. Phase separation in artificial vesicles driven by light and curvature

    Science.gov (United States)

    Rinaldin, Melissa; Pomp, Wim; Schmidt, Thomas; Giomi, Luca; Kraft, Daniela; Physics of Life Processes Team; Soft; Bio Mechanics Collaboration; Self-Assembly in Soft Matter Systems Collaboration

    The role of phase-demixing in living cells, leading to the lipid-raft hypothesis, has been extensively studied. Lipid domains of higher lipid chain order are proposed to regulate protein spatial organization. Giant Unilamellar Vesicles provide an artificial model to study phase separation. So far temperature was used to initiate the process. Here we introduce a new methodology based on the induction of phase separation by light. To this aim, the composition of the lipid membrane is varied by photo-oxidation of lipids. The control of the process gained by using light allowed us to observe vesicle shape fluctuations during phase-demixing. The presence of fluctuations near the critical mixing point resembles features of a critical process. We quantitatively analyze these fluctuations using a 2d elastic model, from which we can estimate the material parameters such as bending rigidity and surface tension, demonstrating the non-equilibrium critical behaviour. Finally, I will describe recent attempts toward tuning the membrane composition by controlling the vesicle curvature.

  1. effect of daylight hours on performance of growing grasscutters

    African Journals Online (AJOL)

    user

    DNA.Many animals use the daily variation in the duration and quantity of melatonin ... such as reproduction, behavior, coat growth and ... behavioral processes in the biological system. The ... spends the daylight hours sleeping or resting. The.

  2. Association between nighttime artificial light pollution and sea turtle nest density along Florida coast: A geospatial study using VIIRS remote sensing data.

    Science.gov (United States)

    Hu, Zhiyong; Hu, Hongda; Huang, Yuxia

    2018-08-01

    Artificial lighting at night has becoming a new type of pollution posing an important anthropogenic environmental pressure on organisms. The objective of this research was to examine the potential association between nighttime artificial light pollution and nest densities of the three main sea turtle species along Florida beaches, including green turtles, loggerheads, and leatherbacks. Sea turtle survey data was obtained from the "Florida Statewide Nesting Beach Survey program". We used the new generation of satellite sensor "Visible Infrared Imaging Radiometer Suite (VIIRS)" (version 1 D/N Band) nighttime annual average radiance composite image data. We defined light pollution as artificial light brightness greater than 10% of the natural sky brightness above 45° of elevation (>1.14 × 10 -11 Wm -2 sr -1 ). We fitted a generalized linear model (GLM), a GLM with eigenvectors spatial filtering (GLM-ESF), and a generalized estimating equations (GEE) approach for each species to examine the potential correlation of nest density with light pollution. Our models are robust and reliable in terms of the ability to deal with data distribution and spatial autocorrelation (SA) issues violating model assumptions. All three models found that nest density is significantly negatively correlated with light pollution for each sea turtle species: the higher light pollution, the lower nest density. The two spatially extended models (GLM-ESF and GEE) show that light pollution influences nest density in a descending order from green turtles, to loggerheads, and then to leatherbacks. The research findings have an implication for sea turtle conservation policy and ordinance making. Near-coastal lights-out ordinances and other approaches to shield lights can protect sea turtles and their nests. The VIIRS DNB light data, having significant improvements over comparable data by its predecessor, the DMSP-OLS, shows promise for continued and improved research about ecological effects of

  3. A Study on the Optimal Duration of Daylight Saving Time (DST in Korea

    Directory of Open Access Journals (Sweden)

    Byeong-Hee Mihn

    2009-09-01

    Full Text Available Daylight saving time aims at spending effective daylight in summer season. Korea had enforced daylight saving time twelve times from 1948 to 1988. Since 1988, it is not executed, but it is recently discussed the resumption of DST. In this paper, we investigate the trend of DST in other countries, review the history of DST in Korea, and suggest the optimal DST duration in terms of astronomical aspects (times of sunrise and sunset. We find that the starting day of DST in Korea is apt for the second Sunday in Mayor the second Sunday in April according to the time of sunrise or to the difference between Korean standard meridian and observer`s, respectively. We also discuss time friction that might be caused by time difference between DST and Korea Standard Time (KST.

  4. Integrated Building Design

    DEFF Research Database (Denmark)

    Heiselberg, Per

    In the first half of the 20th century, HVAC systems and artificial lighting were developed to meet indoor comfort needs. Before the introduction of mechanical systems, climate - not building style or appearance - was the major determinant of building form. Comfort was achieved through passive means...... and architectural features built into the design. However, with the advent of new technologies, architects were no longer constrained by the need to ensure that buildings had ample daylighting, remained airy and cool in the summer and warm in the winter. Since HVAC systems and artificial lighting could satisfy...

  5. DETERMINATION OF THE LIGHT CURVE OF THE ARTIFICIAL SATELLITE BY ITS ROTATION PATH AS PREPARATION TO THE INVERSE PROBLEM SOLUTION

    OpenAIRE

    Pavlenko, Daniil

    2012-01-01

    Developing the algorithm of estimation of the rotational parameters of the artificial satellite by its light curve, we face the necessity to compute test light curves for various initially given types of rotation and specific features of lighting of the satellite. In the present study the algorithm of creation of such light curves with the simulation method and the obtained result are described.

  6. One-pot solvothermal synthesis of highly efficient, daylight active and recyclable Ag/AgBr coupled photocatalysts with synergistic dual photoexcitation

    International Nuclear Information System (INIS)

    Zhang, Caihong; Ai, Lunhong; Li, Lili; Jiang, Jing

    2014-01-01

    Highlights: • Ag/AgBr photocatalysts were controllably synthesized by solvothermal process. • Ag/AgBr composites showed excellent daylight driven photocatalytic activity. • The remarkable activity is attributed to the synergistic dual photoexcitation. -- Abstract: Efficient light harvesting has been considered to be critical for manipulating the photocatalytic behavior of photocatalysts, because it directly determines the generation of reactive redox charge carriers involved in photoreaction process. In this study, we present a successful example on efficient conversion of solar energy by Ag/AgBr coupled photocatalysts that hold unique synergistic dual photoexcitation. A series of Ag/AgBr coupled photocatalysts were controllably synthesized by an easily manipulated mild solvothermal process. The physicochemical properties of the as-prepared Ag/AgBr coupled photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS) and UV–vis diffuse reflectance spectroscopy (DRS). The results showed the solvothermal reaction time played key role for control of crystalline structure, morphology, composition, and visible light absorption ability of the resulting photocatalysts. The as-prepared Ag/AgBr coupled photocatalysts exhibited remarkable photocatalytic performance and good reusability for decomposing organic dyes in aqueous solution under the irradiation of commercial 20 W cool daylight fluorescent lamp, owing to the synergistic dual photoexcitation cooperating between plasmonic Ag nanoparticles and narrow-band-gap AgBr

  7. Dynamic Lighting Concept in Danish Office Environment with Daylight Contribution

    DEFF Research Database (Denmark)

    Logadóttir, Ásta; Christoffersen, Jens

    positioned ~2 respectively ~4 meters from the window. Both the general lighting and desk lamp could be adjusted in correlated colour temperature (CCT) while the general lighting could also be adjusted in intensity. The study was an extension of previous studies conducted without a desk lamp and with subjects...

  8. Comparative Study of Two Daylighting Analysis Methods with Regard to Window Orientation and Interior Wall Reflectance

    Directory of Open Access Journals (Sweden)

    Yeo Beom Yoon

    2014-09-01

    Full Text Available The accuracy and speed of the daylighting analysis developed for use in EnergyPlus is better than its predecessors. In EnergyPlus, the detailed method uses the Split-flux algorithm whereas the DElight method uses the Radiosity algorithm. Many existing studies have addressed the two methods, either individually or compared with other daylight analysis methods like Ray tracing but still there is lack of detailed comparative study of these two methods. Our previous studies show that the Split-flux method overestimates the illuminance, especially for the areas away from the window. The Radiosity method has the advantage of accurately predicting this illuminance because of how it deals with the diffuse light. For this study, the EnergyPlus model, which has been calibrated using data measured in a real building in previous studies, has also been used. The calibrated model has a south oriented window only. This model is then used to analyze the interior illuminance inside the room for north, west and east orientation of the window by rotating the model and by changing the wall reflectance of the model with south oriented window. Direct and diffuse component of the illuminance as well as the algorithms have been compared for a detailed analysis.

  9. Effects of artificial light at night on human health: A literature review of observational and experimental studies applied to exposure assessment.

    Science.gov (United States)

    Cho, YongMin; Ryu, Seung-Hun; Lee, Byeo Ri; Kim, Kyung Hee; Lee, Eunil; Choi, Jaewook

    2015-01-01

    It has frequently been reported that exposure to artificial light at night (ALAN) may cause negative health effects, such as breast cancer, circadian phase disruption and sleep disorders. Here, we reviewed the literature assessing the effects of human exposure to ALAN in order to list the health effects of various aspects of ALAN. Several electronic databases were searched for articles, published through August 2014, related to assessing the effects of exposure to ALAN on human health; these also included the details of experiments on such exposure. A total of 85 articles were included in the review. Several observational studies showed that outdoor ALAN levels are a risk factor for breast cancer and reported that indoor light intensity and individual lighting habits were relevant to this risk. Exposure to artificial bright light during the nighttime suppresses melatonin secretion, increases sleep onset latency (SOL) and increases alertness. Circadian misalignment caused by chronic ALAN exposure may have negative effects on the psychological, cardiovascular and/or metabolic functions. ALAN also causes circadian phase disruption, which increases with longer duration of exposure and with exposure later in the evening. It has also been reported that shorter wavelengths of light preferentially disturb melatonin secretion and cause circadian phase shifts, even if the light is not bright. This literature review may be helpful to understand the health effects of ALAN exposure and suggests that it is necessary to consider various characteristics of artificial light, beyond mere intensity.

  10. The Design and Comparison of Central and Distributed Light Sensored Smart LED Lighting Systems

    Directory of Open Access Journals (Sweden)

    Mehmet Ali Özçelik

    2018-01-01

    Full Text Available There is a lack of published peer-reviewed research comparing the efficiencies of distributed versus central sensor-controlled LED lighting systems. This research proposes improving the smart illumination of a room with external fenestration using central and distributed light sensors. The optical and electrical measurements of the daylight have been made in the case where the light was not distributed evenly and not sufficient. Test results show that the proposed distributed light sensor illumination system has increased the efficiency by 28% when compared to the proposed central system. It has also been shown that the two tested systems are more cost-effective than common smart illumination systems.

  11. Design and assessment of an anidolic light-duct

    Energy Technology Data Exchange (ETDEWEB)

    Courret, G.; Scartezzini, J.L. [Lab. d`Energie Solaire et de Physique du Batiment (LESO-PB), Ecole Polytechnique Federale de Lausanne (Switzerland); Francioli, D.; Meyer, J.J. [Lab. d`Ergonomie de la Vision (LEV), Inst. Univ. Romand de Sante au Travail, Lausanne (Switzerland)

    1998-08-01

    The system presented here, called Anidolic Ceiling, was developed to show the viability of intensive use of daylight by overcast outdoor conditions in nonresidential buildings. This device consists of a light-duct that is integrated in a suspended ceiling and leads midway into the office. Anidolic (nonimaging optics) elements are placed on either end of the duct, on the outside to collect light rays from the sky and on the inside to control the direction of the emitted light. The present paper describes the system design, as well as an experimental assessment of its daylighting performance in a comparison of a prototype and a full-size conventional facade, for a 6.6-m deep room. Measurements by overcast sky have established that the daylight factor on the work plane 5 m from the window is more than doubled. In addition, a monitoring campaign has shown that 30% of the energy for lighting can be saved. The system was also assessed with regard to the user. Visual comfort measurements (Laboratoire d`Ergonomie de la Vision`s (LEV) method) were carried out showing that for both clear and overcast outdoor conditions, the visual environment quality is objectively improved at the rear working place. Furthermore, 33 people tested both rooms one after the other. They were submitted to a series of visual acuity tests on printed paper and on a computer screen and had to fill in a questionnaire. A comparative study showed that the personal appreciation of the luminous environment is better in the room with an Anidolic Ceiling, with a significant reduction of reading errors both on paper and on the screen. (orig.)

  12. Light transmission through intraocular lenses with or without yellow chromophore (blue light filter) and its potential influence on functional vision in everyday environmental conditions.

    Science.gov (United States)

    Owczarek, Grzegorz; Gralewicz, Grzegorz; Skuza, Natalia; Jurowski, Piotr

    2016-01-01

    In this research the factors used to evaluate the light transmission through two types of acrylic hydrophobic intraocular lenses, one that contained yellow chromophore that blocks blue light transmission and the other which did not contain that filter, were defined according to various light condition, e.g., daylight and at night. The potential influence of light transmission trough intraocular lenses with or without yellow chromophore on functional vision in everyday environmental conditions was analysed.

  13. Daylight Savings Time Transitions and the Incidence Rate of Unipolar Depressive Episodes.

    Science.gov (United States)

    Hansen, Bertel T; Sønderskov, Kim M; Hageman, Ida; Dinesen, Peter T; Østergaard, Søren D

    2017-05-01

    Daylight savings time transitions affect approximately 1.6 billion people worldwide. Prior studies have documented associations between daylight savings time transitions and adverse health outcomes, but it remains unknown whether they also cause an increase in the incidence rate of depressive episodes. This seems likely because daylight savings time transitions affect circadian rhythms, which are implicated in the etiology of depressive disorder. Therefore, we investigated the effects of daylight savings time transitions on the incidence rate of unipolar depressive episodes. Using time series intervention analysis of nationwide data from the Danish Psychiatric Central Research Register from 1995 to 2012, we compared the observed trend in the incidence rate of hospital contacts for unipolar depressive episodes after the transitions to and from summer time to the predicted trend in the incidence rate. The analyses were based on 185,419 hospital contacts for unipolar depression and showed that the transition from summer time to standard time were associated with an 11% increase (95% CI = 7%, 15%) in the incidence rate of unipolar depressive episodes that dissipated over approximately 10 weeks. The transition from standard time to summer time was not associated with a parallel change in the incidence rate of unipolar depressive episodes. This study shows that the transition from summer time to standard time was associated with an increase in the incidence rate of unipolar depressive episodes. Distress associated with the sudden advancement of sunset, marking the coming of a long period of short days, may explain this finding. See video abstract at, http://links.lww.com/EDE/B179.

  14. Analyzing Traffic Crash Severity in Work Zones under Different Light Conditions

    Directory of Open Access Journals (Sweden)

    Xinxin Wei

    2017-01-01

    Full Text Available Previous studies have investigated various factors that contribute to the severity of work zone crashes. However, little has been done on the specific effects of light conditions. Using the data from the Enhanced Tennessee Roadway Information Management System (E-TRIMS, crashes that occurred in the Tennessee work zones during 2003–2015 are categorized into three light conditions: daylight, dark-lighted, and dark-not-lighted. One commonly used decision tree method—Classification and Regression Trees (CART—is adopted to investigate the factors contributing to crash severity in highway work zones under these light conditions. The outcomes from the three decision trees with differing light conditions show significant differences in the ranking and importance of the factors considered in the study, thereby indicating the necessity of examining traffic crashes according to light conditions. By separately considering the crash characteristics under different light conditions, some new findings are obtained from this study. The study shows that an increase in the number of lanes increases the crash severity level in work zones during the day while decreasing the severity at night. Similarly, drugs and alcohol are found to increase the severity level significantly under the dark-not-lighted condition, while they have a limited influence under daylight and dark-lighted conditions.

  15. How daylight influences high-order chromatic descriptors in natural images.

    Science.gov (United States)

    Ojeda, Juan; Nieves, Juan Luis; Romero, Javier

    2017-07-01

    Despite the global and local daylight changes naturally occurring in natural scenes, the human visual system usually adapts quite well to those changes, developing a stable color perception. Nevertheless, the influence of daylight in modeling natural image statistics is not fully understood and has received little attention. The aim of this work was to analyze the influence of daylight changes in different high-order chromatic descriptors (i.e., color volume, color gamut, and number of discernible colors) derived from 350 color images, which were rendered under 108 natural illuminants with Correlated Color Temperatures (CCT) from 2735 to 25,889 K. Results suggest that chromatic and luminance information is almost constant and does not depend on the CCT of the illuminant for values above 14,000 K. Nevertheless, differences between the red-green and blue-yellow image components were found below that CCT, with most of the statistical descriptors analyzed showing local extremes in the range 2950 K-6300 K. Uniform regions and areas of the images attracting observers' attention were also considered in this analysis and were characterized by their patchiness index and their saliency maps. Meanwhile, the results of the patchiness index do not show a clear dependence on CCT, and it is remarkable that a significant reduction in the number of discernible colors (58% on average) was found when the images were masked with their corresponding saliency maps. Our results suggest that chromatic diversity, as defined in terms of the discernible colors, can be strongly reduced when an observer scans a natural scene. These findings support the idea that a reduction in the number of discernible colors will guide visual saliency and attention. Whatever the modeling is mediating the neural representation of natural images, natural image statistics, it is clear that natural image statistics should take into account those local maxima and minima depending on the daylight illumination and

  16. Impact of shading on daylight quality. Simulations with radiance

    Energy Technology Data Exchange (ETDEWEB)

    Dubois, M.C.

    2001-07-01

    The impact of six exterior shading devices on daylight quality and on the potential for daylight utilisation in a standard, south-oriented office room was investigated through computer simulations with Radiance. The daylight quality was evaluated by considering four performance indicators: the absolute work plane illuminance, the illuminance uniformity on the work plane, the absolute luminance in the visual field and the luminance ratios between the work plane, VDT screen and surrounding surfaces. The results indicate that the overhang, white awning and horizontal venetian blind generated work plane illuminance levels that are more suitable for offices where traditional tasks are carried out. However, these devices did not prevent high luminance values at the window. On the other hand, the grey specular screen produced unacceptably low work plane illuminance, poor illuminance uniformity and unacceptably low luminance levels which resulted in unsuitable luminance ratios between the VDT screen, work plane and surroundings. The 45 deg venetian blind, white screen and blue awning provided work plane illuminance levels suitable for offices where a combination of paper and computer work is carried out. They also provided acceptable illuminance uniformity on the work plane, suitable luminance ratios between the work plane, VDT screen and surroundings and they significantly reduced the luminance of the window. However, the blue awning had a poorer performance in December than in June and the white screen resulted in high luminance values at the window, which indicates that the best device among the ones studied was the 45 deg venetian blind.

  17. Examination of Color-Lighting Control System Using Colored Paper User Interface

    OpenAIRE

    Aida Hiroto; Matsui Kento; Keisuke Soma; Murakami Hiroki; Miki Mistunori

    2016-01-01

    In recent year, Full-Color LED Lighting that can be changed to various color such as red, green, blue has been appeared with development of LED Lighting. By Color-Lighting control, users affected such as concentrating and relaxing. Therefore, Color-lighting control will spread to various place such as home, offices, stations. However color-lighting control affected some disturbance such as daylight, display when Full-Color LED controlled indoors. Also, information devices control get difficul...

  18. Short communication: Artificial ultraviolet B light exposure increases vitamin D levels in cow plasma and milk

    DEFF Research Database (Denmark)

    Jakobsen, Jette; Jensen, Søren Krogh; Hymøller, Lone

    2015-01-01

    tested the ability of a specially designed UVB lamp to enhance the vitamin D-3 content in milk from dairy cows housed indoors. This study included 16 cows divided into 4 groups. Each group was exposed daily to artificial UVB light simulating 1, 2, 3, or 4 h of summer sun at 56 degrees N for 24 d...... exposure to artificial UVB light to 73 d did not lead to an increase of vitamin D-3 or 25OHD(3) level in the milk. In conclusion, the change in production facilities for dairy cows providing cows with no access to pasture and sunlight causes a decrease of vitamin D levels in dairy products. This decrease......The number of dairy cows without access to pasture or sunlight is increasing; therefore, the content of vitamin D in dairy products is decreasing. Ultimately, declining vitamin D levels in dairy products will mean that dairy products are a negligible source of natural vitamin D for humans. We...

  19. A review of methods for the evaluation of the energy contribution of daylight in buildings

    Energy Technology Data Exchange (ETDEWEB)

    Attenborough, M; Goodwin, A

    1996-07-01

    A review has been undertaken of energy prediction methods and daylight calculation methods currently in use in the UK. This was based on a literature review and discussions with large engineering practices and academics involved in the areas of daylighting and energy simulation research. The aim of this review was to identify manual methods or computer programs that are capable of determining energy use in non-domestic buildings and of taking into account the energy savings resulting from daylighting. One potential application for these methods is in supporting anticipated energy targets for non-domestic buildings within Building Regulations and other energy labelling schemes. The review has identified a range of methods which are capable of predicting overall energy use while accounting for daylight. These vary in complexity from empirical methods such as ESICHECK and the CIBSE Energy Code through to dynamic energy simulation models such as DOE 2 and ESP. For each of the methods identified a brief assessment has been made of their technical capabilities ease of use and availability. These assessments have been based on discussions with users and program developers. Descriptions of the various methods are given. (Author)

  20. Artificial night lighting rather than traffic noise affects the daily timing of dawn and dusk singing in common European songbirds

    NARCIS (Netherlands)

    Da Silva, Arnaud; Samplonius, Jelmer Menno; Schlicht, Emmi; Valcu, Mihai; Kempenaers, Bart

    2014-01-01

    It is well established that artificial night lighting can influence animal orientation, but there is less information about its effects on other behaviors. Previous work suggested that light pollution can affect both seasonal and daily patterns of behavior. The aim of our study was to investigate

  1. Cost/effectiveness aspects of road lighting : contribution to CIE TC 4.6 Symposium on Measures of Road Lighting Effectiveness, Karlsruhe, 5-6 July, 1977. Session II - Road lighting and accidents.

    NARCIS (Netherlands)

    Flury, F.C.

    1977-01-01

    The common method to determine the effect of road lighting on traffic safety, is to compare accident numbers during daylight and darkness, before and after the measure is taken. This approach ignores the possibility of increased risk of collisions with road side obstacles due to the erection of

  2. Low levels of vitamin D poorly responsive to daylight exposure in patients with therapy-resistant schizophrenia.

    Science.gov (United States)

    Bogers, Jan P.A.M.; Bostoen, Tijmen; Broekman, Theo G.

    2016-01-01

    Low vitamin D levels are associated with schizophrenia, but the possible association between vitamin D levels and illness severity or duration of exposure to daylight has barely been investigated. To compare vitamin D levels in therapy-refractory severely ill schizophrenia patients and members of staff. To investigate the influence of daylight exposure on vitamin D levels in patients. Vitamin D was measured in patients with therapy-resistant schizophrenia in April, after the winter, and in patients and staff members in June, after an exceptionally sunny spring. Vitamin D levels in April and June were compared in patients, and levels in June were compared in patients and staff. The influence of daylight was taken into account by comparing the time patients spent outdoors during the day with the recommended minimum time for adequate vitamin D synthesis, and by comparing time spent outdoors in patients and staff. Patients had high rates of vitamin D deficiency (79-90%) and lower levels of vitamin D than staff members (p vitamin D levels did not normalize, despite the considerably longer than recommended exposure of the skin to daylight (p vitamin D deficiency of therapy-resistant schizophrenia patients is pronounced and cannot be explained by differences in skin pigmentation or by an inactive, indoor lifestyle on the ward. Even theoretically sufficient exposure of the patients to daylight did not ameliorate the low vitamin D levels. While vitamin D deficiency probably plays a role in somatic health problems, it may also play a role in schizophrenia. Interestingly, exposure to daylight during an unusually sunny spring was not sufficient to correct the vitamin D deficiency seen in the patients. This emphasizes the need to measure and correct vitamin D levels in these patients.

  3. Solar shading for low energy use and daylight quality in offices: Simulations, measurements and design tools

    Energy Technology Data Exchange (ETDEWEB)

    Dubois, M.C.

    2001-11-01

    This thesis investigates the impact of solar shading devices on energy use and daylight quality in office rooms. The impact on energy use is analysed through computer simulations with the dynamic energy simulation program Derob-LTH while the impact on daylight quality is investigated through measurements in full-scale experimental office rooms and simulations with the program Radiance. This thesis also includes a literature review of research on solar shading as well as design tools to incorporate shading devices at an early stage in the design of buildings. This thesis indicates that, in cold countries, shading devices may provide more annual energy savings than any solar-protective (reflective, tinted) glazing and that the optimum glazing transmittance is orientation- and climate-dependent. For example, high annual energy savings are obtained on the south facade with higher transmittance glazings (compared with the east and west facade) because the potential for passive solar gain utilisation in the winter is high in comparison with the annual cooling demand. Exterior shading devices like awnings and overhangs may reduce the cooling demand dramatically but they are not suitable as daylight (glare) control devices. Devices like screens and venetian blinds are preferable because they cover the entire window area, which prevents sunlight patches in the room and the direct view of the bright sky. Screens and venetian blinds also reduce daylight in the room to levels that are suitable for computer work. However, it is essential that the screen is of a diffusing type since screens with a strong (specular) transmittance component result in poor daylight quality. The study on daylight quality also indicated that a screen transmittance of around 15 % may be optimum for a standard (3.5 by 6.0 m{sup 2}) south-oriented office room with a window covering around 25 % of the facade area (12 % of the floor area)

  4. Study on the living environment of semi-underground room with attached green house; Fusetsu onshitsu no aru hanchikashitsu no kyojusei ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, T; Tsukayama, N [Ochanomizu University, Tokyo (Japan)

    1996-10-27

    In response to demand for the expansion of living space, the living environment of semi-underground room has been investigated. An attached green house (passive solar house) is adjacent to the semi-underground room. This is reinforced concrete construction, having flat type solar collector on its roof and lighting window in its north side. It does not have artificial air conditioners. Based on the measurements of daylight factor, artificial lighting is not required at the window in the daytime, but it is desirable to use daylight and artificial lighting together at the center. The performance of sound insulation depends on the high performance soundproof sash level. There is less daily temperature variation due to its large heat capacity, and less yearly temperature variation than the outside. By shielding the solar radiation, the insolation in the green house in summer can be restricted in the same as in winter. The insolation can be easily received in winter due to its large vertical intensity of solar radiation. The green house in the south side is useful for improving the living environment of semi-underground room. The temperature rise in the semi-underground room can be restricted by opening window in summer. It is desirable for the comfortable living to use artificial cooling to reduce the daytime temperature by 3 to 4{degree}C. In winter, it is comfortable to heat by 4 to 5{degree}C. 2 refs., 7 figs.

  5. Fabrication of thin-film thermoelectric generators with ball lenses for conversion of near-infrared solar light

    Science.gov (United States)

    Ito, Yoshitaka; Mizoshiri, Mizue; Mikami, Masashi; Kondo, Tasuku; Sakurai, Junpei; Hata, Seiichi

    2017-06-01

    We designed and fabricated thin-film thermoelectric generators (TEGs) with ball lenses, which separated visible light and near-infrared (NIR) solar light using a chromatic aberration. The transmitted visible light was used as daylight and the NIR light was used for thermoelectric generation. Solar light was estimated to be separated into the visible light and NIR light by a ray tracing method. 92.7% of the visible light was used as daylight and 9.9% of the NIR light was used for thermoelectric generation. Then, the temperature difference of the pn junctions of the TEG surface was 0.71 K, determined by heat conduction analysis using a finite element method. The thin-film TEGs were fabricated using lithography and deposition processes. When the solar light (A.M. 1.5) was irradiated to the TEGs, the open-circuit voltage and maximum power were 4.5 V/m2 and 51 µW/m2, respectively. These TEGs are expected to be used as an energy supply for Internet of Things sensors.

  6. A simple tool to evaluate the effect of the urban canyon on daylight level and energy demand in the early stages of building design

    DEFF Research Database (Denmark)

    Petersen, Steffen; Momme, Amalie Jin; Hviid, Christian Anker

    2014-01-01

    Daylight is a restricted resource in urban contexts. Rooms situated in an urban context often have a significant proportion of the sky and the sun blocked out by the urban building mass. The reduced direct daylight potential makes daylight reflected from outdoor surfaces an important daylight sou...... the impact of urban canyon parameters on indoor environment and energy performance....

  7. Porphyrin nanorods characterisation for an artificial light harvesting and energy transfer system

    CSIR Research Space (South Africa)

    Mongwaketsi, N

    2010-01-01

    Full Text Available s 1 0 h r s 1 3 h r s 1 5 h r s 1 8 h r s Porphyrin Nanorods Characterization for an Artificial Light Harvesting and Energy Transfer System Nametso Mongwaketsi1,2,3, Raymond Sparrow2, Bert Klumperman3, Malik Maaza1 1 NanoSciences Lab..., Materials Research Dept, iThemba LABS, PO Box 722, Somerset West, 7129, South Africa 2 CSIR Biosciences, PO Box 395, Pretoria, 0001, South Africa 3 Stellenbosch University, Department of Chemistry and Polymer Science, Private Bag X 1, Matieland, 7602...

  8. Quantifying the potential of automated dynamic solar shading in office buildings through integrated simulations of energy and daylight

    DEFF Research Database (Denmark)

    Nielsen, Martin Vraa; Svendsen, Svend; Bjerregaard Jensen, Lotte

    2011-01-01

    The façade design is and should be considered a central issue in the design of energy-efficient buildings. That is why dynamic façade components are increasingly used to adapt to both internal and external impacts, and to cope with a reduction in energy consumption and an increase in occupant...... them with various window heights and orientations. Their performance was evaluated on the basis of the building’s total energy demand, its energy demand for heating, cooling and lighting, and also its daylight factors. Simulation results comparing the three façade alternatives show potential...

  9. Individual dynamic lighting control in a daylit space

    DEFF Research Database (Denmark)

    Logadóttir, Asta; Christoffersen, Jens

    2008-01-01

    in combination with daylight. Subjects performed office work for one day in a simulated office environment. Every 30 minutes the subjects were invited to use the dimmer controls to change the lighting conditions to their preferred level. Measurements were made of illuminance, luminance, CCT and energy use......The objectives of the study are to observe individual preferences for dynamic lighting, individual control and possibly achieve energy savings in a daylit space. The dynamics in this study are modifications of light level and correlated colour temperature (CCT) from the electric lighting system...

  10. Solar Shading System Based on Daylight Directing Glass Lamellas

    DEFF Research Database (Denmark)

    Laustsen, Jacob Birck; Santos, Inês; Svendsen, Svend

    2008-01-01

    The overheating problems in office buildings must be solved with efficient solar shadings in order to reduce the energy demand for cooling and ventilation. At the same time the solar shading should not reduce the daylight level in the building on overcast days because it would result in a lower...

  11. An artificial solar spectrum substantially alters plant development compared with usual climate room irradiance spectra

    NARCIS (Netherlands)

    Hogewoning, S.W.; Douwstra, P.; Trouwborst, G.; Ieperen, van W.; Harbinson, J.

    2010-01-01

    Plant responses to the light spectrum under which plants are grown affect their developmental characteristics in a complicated manner. Lamps widely used to provide growth irradiance emit spectra which are very different from natural daylight spectra. Whereas specific responses of plants to a

  12. An innovative roofing system for tropical building interiors: Separating heat from useful visible light

    Energy Technology Data Exchange (ETDEWEB)

    Al-Obaidi, K.M.; Ismail, M.; Abdul Rahman, A.M. [School of Housing, Building and Planning, Universiti Sains Malaysia, 11800, Minden, Pulau Pinang (Malaysia)

    2013-07-01

    Generally it has been known that energy consumption costs are high in temperate countries. In buildings, room spaces are normally designed so as to consume less energy for thermal comfort especially in winter. Passive strategies such large double-glazing windows are to contain heat indoors and also for maximum daylight to reduce dependence on artificial lighting. Thus roof lights are popular building design elements in cold and temperate countries. Unlike in the tropics where it has high temperatures and humidity throughout the year, achieving indoor comfort is a challenge especially with plenty of sunshine and unpredictable wind conditions. This paper explores the possibility of roof light for indoor comfort to be considered as a tropical design element. Initial simulation was carried out before any attempt to do life-sized model for empirical data. By simulation, the hypothesis has been achieved but several factors have to be considered. The solution is not as simple as those achieved in the temperate countries. Comfort can be achieved but permutations of several design factors such as dimensions of room, glazing, reflective materials, blackbody concept and building materials need adjustment to meet the Malaysian Comfort Temperature. With this finding the Tropical Architecture would then be redefined with the introduction of this Innovative Roofing System (IRS) as named by the author.

  13. Artificial Leaf Based on Artificial Photosynthesis for Solar Fuel Production

    Science.gov (United States)

    2017-06-30

    collect light energy and separate charge for developing new types of nanobiodevices to construct ”artificial leaf” from solar to fuel. or Concept of...AFRL-AFOSR-JP-TR-2017-0054 Artificial Leaf Based on Artificial Photosynthesis for Solar Fuel Production Mamoru Nango NAGOYA INSTITUTE OF TECHNOLOGY...display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ORGANIZATION. 1. REPORT DATE (DD-MM-YYYY)      30-06-2017 2

  14. Implementing non-image-forming effects of light in the built environment : A review on what we need

    NARCIS (Netherlands)

    Khademagha, P.; Aries, M.B.C.; Rosemann, A.L.P.; van Loenen, E.J.

    2016-01-01

    This paper presents a theoretical framework for incorporating the non-image-forming effects of light into daylighting design in the built environment. The framework includes human performance indicators to measure the magnitude of the non-image-forming effects of light as well as light factors to

  15. Chronic exposure to dim artificial light at night decreases fecundity and adult survival in Drosophila melanogaster.

    Science.gov (United States)

    McLay, L K; Green, M P; Jones, T M

    2017-07-01

    The presence of artificial light at night is expanding in geographical range and increasing in intensity to such an extent that species living in urban environments may never experience natural darkness. The negative ecological consequences of artificial night lighting have been identified in several key life history traits across multiple taxa (albeit with a strong vertebrate focus); comparable data for invertebrates is lacking. In this study, we explored the effect of chronic exposure to different night-time lighting intensities on growth, reproduction and survival in Drosophila melanogaster. We reared three generations of flies under identical daytime light conditions (2600lx) and one of four ecologically relevant ALAN treatments (0, 1, 10 or 100lx), then explored variation in oviposition, number of eggs produced, juvenile growth and survival and adult survival. We found that, in the presence of light at night (1, 10 and 100lx treatments), the probability of a female commencing oviposition and the number of eggs laid was significantly reduced. This did not translate into differences at the juvenile phase: juvenile development times and the probability of eclosing as an adult were comparable across all treatments. However, we demonstrate for the first time a direct link between chronic exposure to light at night (greater than 1lx) and adult survival. Our data highlight that ALAN has the capacity to cause dramatic shifts in multiple life history traits at both the individual and population level. Such shifts are likely to be species-specific, however a more in depth understanding of the broad-scale impact of ALAN and the relevant mechanisms driving biological change is urgently required as we move into an increasing brightly lit future. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Low cost data acquisition module for evaluating the quantitative performance of daylight systems

    Energy Technology Data Exchange (ETDEWEB)

    Ciampini, F.; Scarazzato, P.S. [Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo, P.O. Box 6021, CEP 13083-852 Campinas (Brazil); Neves, A.A.R. [Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin, Departamento de Eletronica Quantica, P.O. Box 6165, 13083-970 Campinas (Brazil); Pereira, D.C.L.; Yamanaka, M.H. [Universidade de Sao Paulo, Faculdade de Arquitetura e Urbanismo, Departamento de Tecnologia da Arquitetura, Rua do Lago, 878 CEP 05508-080, Sao Paulo (Brazil)

    2007-09-15

    The search for efficient, auto-sustainable constructions that allows the user a contact with the outer environment has stimulated the development of advanced strategies, in various devices, for the exploitation of the daylight. A low cost data acquisition system was developed in this study, to observe the distribution of the natural light inside a prototype and to evaluate the quantitative performance for redirecting systems. The luminous sensor is a light dependent resistor, that responds to the illuminance with a reduction in the resistance when illuminated, through a log-log dependence. Calibration curves are set up to relate the change of resistance to absolute illuminance. It therefore provides a continuous investigation of the illuminance for various sampled points in the interior test space with a 0.03% digital error due to the 12-bit resolution. The final measured error of 5% is mainly due to the system calibration and resistance memory history. The circuit connects to a standard parallel port of any Personal Computer and supplies 64 analog inputs, one for each luminous sensor. The circuit can be easily modified to attend different quantities of analog inputs or communication ports. (author)

  17. Impact of different colours of artificial light at night on melatonin rhythm and gene expression of gonadotropins in European perch.

    Science.gov (United States)

    Brüning, Anika; Hölker, Franz; Franke, Steffen; Kleiner, Wibke; Kloas, Werner

    2016-02-01

    The distribution and intensity of artificial light at night, commonly referred to as light pollution, is consequently rising and progressively also ecological implications come to light. Low intensity light is known to suppress nocturnal melatonin production in several fish species. This study aims to examine the least suppressive light colour for melatonin excreted into the holding water and the influence of different light qualities and quantities in the night on gene expression of gonadotropins in fish. European perch (Perca fluviatilis) were exposed to light of different wavelengths during the night (blue, green, and red). Melatonin concentrations were measured from water samples every 3h during a 24h period. Gene expression of gonadotropins was measured in perch exposed to different light colours and was additionally examined for perch subjected to different intensities of white light (0 lx, 1 lx, 10 lx, 100 lx) during the night. All different light colours caused a significant drop of melatonin concentration; however, blue light was least suppressive. Gene expression of gonadotropins was not influenced by nocturnal light of different light colours, but in female perch gonadotropin expression was significantly reduced by white light already at the lowest level (1 lx). We conclude that artificial light with shorter wavelengths at night is less effective in disturbing biological rhythms of perch than longer wavelengths, coinciding with the light situation in freshwater habitats inhabited by perch. Different light colours in the night showed no significant effect on gonadotropin expression, but white light in the night can disturb reproductive traits already at very low light intensities. These findings indicate that light pollution has not only the potential to disturb the melatonin cycle but also the reproductive rhythm and may therefore have implications on whole species communities. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Impact of daylight saving time on road traffic collision risk: a systematic review.

    Science.gov (United States)

    Carey, Rachel N; Sarma, Kiran M

    2017-07-02

    Bills have been put forward in the UK and Republic of Ireland proposing a move to Central European Time (CET). Proponents argue that such a change will have benefits for road safety, with daylight being shifted from the morning, when collision risk is lower, to the evening, when risk is higher. Studies examining the impact of daylight saving time (DST) on road traffic collision risk can help inform the debate on the potential road safety benefits of a move to CET. The objective of this systematic review was to examine the impact of DST on collision risk. Major electronic databases were searched, with no restrictions as to date of publication (the last search was performed in January 2017). Access to unpublished reports was requested through an international expert group. Studies that provided a quantitative analysis of the effect of DST on road safety-related outcomes were included. The primary outcomes of interest were road traffic collisions, injuries and fatalities. Twenty-four studies met the inclusion criteria. Seventeen examined the short-term impact of transitions around DST and 12 examined long-term effects. Findings from the short-term studies were inconsistent. The long-term findings suggested a positive effect of DST. However, this cannot be attributed solely to DST, as a range of road collision risk factors vary over time. The evidence from this review cannot support or refute the assertion that a permanent shift in light from morning to evening will have a road safety benefit. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  19. Evaluation and Improvement of the CIE Metameric and Colour Rendering Index

    Directory of Open Access Journals (Sweden)

    Radovan Slavuj

    2015-12-01

    Full Text Available All artificial light sources are intended to simulate daylight and its properties of color rendering or ability of colour discrimination. Two indices, defined by the CIE, are used to quantify quality of the artificial light sources. First is Color Rendering Index which quantifies ability of light sources to render colours and other is the Metemerism Index which describes metamerism potential of given light source. Calculation of both indices are defined by CIE and has been a subject of discussion and change in past. In this work particularly, the problem of sample number and type used in calculation is addressed here and evaluated. It is noticed that both indices depends on the choice and sample number and that they should be determined based on application.

  20. Switching From Conventional Photodynamic Therapy to Daylight Photodynamic Therapy For Actinic Keratoses: Systematic Review and Meta-analysis.

    Science.gov (United States)

    Tomás-Velázquez, A; Redondo, P

    2017-05-01

    Actinic keratosis is a precursor lesion to the most common nonmelanoma skin cancer. Conventional photodynamic therapy (PDT) has been shown to be effective, but the procedure is time-consuming, can be very painful, and requires infrastructure. These shortcomings led to the emergence of daylight PDT. To obtain a global estimate of efficacy, we undertook a systematic literature review and performed a meta-analysis of the available evidence on the efficacy and safety of daylight PDT as compared to conventional PDT in the treatment of actinic keratosis and/or field cancerization. The conclusion is that the difference in efficacy is clinically negligible (global estimate of the mean response rate difference, -3.69%; 95% CI, -6.54% to -0.84%). The adverse effects of daylight PDT are mild and localized (79% of patients report no discomfort), and patients report less pain (P<.001). Daylight PDT gives good to excellent cosmetic results in more than 90% of patients, and patient satisfaction is greater (P<.001). Copyright © 2016 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.

  1. Effect of window glazing on colour quality of transmitted daylight

    NARCIS (Netherlands)

    Dangol, R.; Kruisselbrink, T.W.; Rosemann, A.L.P.

    2017-01-01

    In this study, the colour quality of the daylight transmitted through different window glazing types is evaluated. The analysis considered four different types of window glazing: laminated, monolithic, coated and applied film glazing ranging in luminous transmittance from around 0.97 to <0.1. The

  2. Human-centered sensor-based Bayesian control: Increased energy efficiency and user satisfaction in commercial lighting

    Science.gov (United States)

    Granderson, Jessica Ann

    2007-12-01

    The need for sustainable, efficient energy systems is the motivation that drove this research, which targeted the design of an intelligent commercial lighting system. Lighting in commercial buildings consumes approximately 13% of all the electricity generated in the US. Advanced lighting controls1 intended for use in commercial office spaces have proven to save up to 45% in electricity consumption. However, they currently comprise only a fraction of the market share, resulting in a missed opportunity to conserve energy. The research goals driving this dissertation relate directly to barriers hindering widespread adoption---increase user satisfaction, and provide increased energy savings through more sophisticated control. To satisfy these goals an influence diagram was developed to perform daylighting actuation. This algorithm was designed to balance the potentially conflicting lighting preferences of building occupants, with the efficiency desires of building facilities management. A supervisory control policy was designed to implement load shedding under a demand response tariff. Such tariffs offer incentives for customers to reduce their consumption during periods of peak demand, trough price reductions. In developing the value function occupant user testing was conducted to determine that computer and paper tasks require different illuminance levels, and that user preferences are sufficiently consistent to attain statistical significance. Approximately ten facilities managers were also interviewed and surveyed to isolate their lighting preferences with respect to measures of lighting quality and energy savings. Results from both simulation and physical implementation and user testing indicate that the intelligent controller can increase occupant satisfaction, efficiency, cost savings, and management satisfaction, with respect to existing commercial daylighting systems. Several important contributions were realized by satisfying the research goals. A general

  3. The effect of short exposure to coloured light on thermal perception: a study using Virtual Reality

    OpenAIRE

    Chinazzo, Giorgia; Chamilothori, Kynthia; Wienold, Jan; Andersen, Marilyne

    2017-01-01

    This study investigates the effect of short exposure to coloured light on thermal perception. To give the impression of natural daylight passing through coloured filters, but avoiding the drawbacks of conducting an experiment with daylight, continuously changing due to daily and seasonal variations, and to weather conditions, we investigate the use of Virtual Reality as a means to control the visual conditions, creating a hybrid environment with thermal and visual stimuli from the real and vi...

  4. Hydrothermal synthesis and white light emission of cubic ZrO2:Eu3+ nanocrystals

    International Nuclear Information System (INIS)

    Meetei, Sanoujam Dhiren; Singh, Shougaijam Dorendrajit

    2014-01-01

    Highlights: • White light emitting cubic ZrO 2 :Eu 3+ nanocrystal is synthesized by hydrothermal technique. • Eu 3+ is used to stabilize crystalline phase and to get red counterpart of the white light. • Defect emission and Eu 3+ emission combined to give white light. • The white light emitted from this nanocrystal resembles vertical daylight of the Sun. • Lifetime corresponding to red counterpart of the sample is far longer than conventional white light emitters. -- Abstract: Production of white light has been a promising area of luminescence studies. In this work, white light emitting nanocrystals of cubic zirconia doped with Eu 3+ are synthesized by hydrothermal technique. The dopant Eu 3+ is used to stabilize crystalline phase to cubic and at the same time to get red counterpart of the white light. The synthesis procedure is simple and precursor required no further annealing for crystallization. X-ray diffraction patterns show the crystalline phase of ZrO 2 :Eu 3+ to be cubic and it is confirmed by Fourier Transform Infrared spectroscopy. From transmission electron microscopy images, size of the crystals is found to be ∼5 nm. Photoluminescence emission spectrum of the sample, on monitoring excitation at O 2− –Eu 3+ charge transfer state shows broad peak due to O 2− of the zirconia and that of Eu 3+ emission. Commission Internationale de l’éclairage co-ordinate of this nanocrystal (0.32, 0.34) is closed to that of the ideal white light (0.33, 0.33). Correlated color temperature of the white light (5894 K) is within the range of vertical daylight. Lifetime (1.32 ms) corresponding to 5 D 0 energy level of the Eu 3+ is found to be far longer than conventional red counterparts of white light emitters. It suggests that the ZrO 2 :Eu 3+ nanocrystals synthesized by hydrothermal technique may find applications in simulating the vertical daylight of the Sun

  5. Experimental illumination of natural habitat-an experimental set-up to assess the direct and indirect ecological consequences of artificial light of different spectral composition

    NARCIS (Netherlands)

    Spoelstra, Kamiel; van Grunsven, Roy H. A.; Donners, Maurice; Gienapp, Phillip; Huigens, Martinus E.; Slaterus, Roy; Berendse, Frank; Visser, Marcel E.; Veenendaal, Elmar

    2015-01-01

    Artificial night-time illumination of natural habitats has increased dramatically over the past few decades. Generally, studies that assess the impact of artificial light on various species in the wild make use of existing illumination and are therefore correlative. Moreover, studies mostly focus on

  6. Artificial Intelligence in Astronomy

    Science.gov (United States)

    Devinney, E. J.; Prša, A.; Guinan, E. F.; Degeorge, M.

    2010-12-01

    From the perspective (and bias) as Eclipsing Binary researchers, we give a brief overview of the development of Artificial Intelligence (AI) applications, describe major application areas of AI in astronomy, and illustrate the power of an AI approach in an application developed under the EBAI (Eclipsing Binaries via Artificial Intelligence) project, which employs Artificial Neural Network technology for estimating light curve solution parameters of eclipsing binary systems.

  7. Sunscope natural light systems : tubular skylights

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    This brochure described a tubular skylight designed by Sunscope Natural Light Systems. The Sunscope is a super-reflective light system in which daylight is reflected down a cylinder to a translucent ceiling fixture that diffuses natural light throughout the room in which it is placed. The Sunscope requires no structure changes, is installed in less than 3 hours, and requires no drywall repairs or repainting. The system eliminates the need for daytime electric lighting, and causes no winter heat losses or summer heat gains. Available in 3 sizes, the Sunscope has no moving parts and is fully maintenance-free. The system was designed for use in commercial and residential applications. 7 figs.

  8. Analysing the impact of reflectance distributions and well geometries on vertical surface daylight levels in atria for overcast skies

    Energy Technology Data Exchange (ETDEWEB)

    Du, Jiangtao; Sharples, Steve [School of Architecture, University of Sheffield, Crookesmoor Building, Conduit Road, Sheffield S10 1FL (United Kingdom)

    2010-07-15

    This study investigated the impacts of different diffuse reflectance distributions and well geometries on vertical daylight factors and vertical internally reflected components in atria. Two forms of reflectance distribution patterns of wall surface were examined: horizontal and vertical reflectance band variation. The square atrium models studied have a broader WI range of 0.25-2.0, which represent shallow, medium and high atria. Radiance, a powerful package based on backward ray tracing technique, was used for the simulations of vertical daylight levels. The results show that different reflectance distributions of square atrium walls do have an impact on the vertical daylight factors and vertical internally reflected components under overcast sky condition. The impact relates to the orientation of the band with different reflectance distributions on the wall. Compared with the vertical band surface, the horizontal band surface has a much more complicated effect. The horizontal distributions of the reflectances significantly affects the vertical daylight levels at the locations more than 30% atrium height on the wall. For an atrium with a height more than 1/2 the width, the effect tends to increase with the increasing well index. The vertical distributions of the reflectance, nevertheless, do not substantially take effect on the vertical daylight levels in atria except for some special reflectance distribution patterns. (author)

  9. Light's labour's lost - policies for energy-efficient lighting

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-06-29

    When William Shakepeare wrote Love's Labour's Lost he would have used light from tallow candles at a cost (today) of 12,000 British pounds per million-lumen hours. The same amount of light from electric lamps now costs only 2 pounds! But today's low-cost illumination still has a dark side. Globally, lighting consumes more electricity than is produced by either hydro or nuclear power and results in CO2 emissions equivalent to two thirds of the world's cars. A standard incandescent lamp may be much more efficient than a tallow candle, but it is far less efficient than a high-pressure sodium lamp. Were inefficient light sources to be replaced by the equivalent efficient ones, global lighting energy demand would be up to 40% less at a lower overall cost. Larger savings still could be realised through the intelligent use of controls, lighting levels and daylight. But achieving efficient lighting is not just a question of technology; it requires policies to transform current practice. This book documents the broad range of policy measures to stimulate efficient lighting that have already been implemented around the world and suggests new ways these could be strengthened to prevent light's labour's from being lost.

  10. Light's labour's lost - policies for energy-efficient lighting

    International Nuclear Information System (INIS)

    2006-01-01

    When William Shakepeare wrote Love's Labour's Lost he would have used light from tallow candles at a cost (today) of 12,000 British pounds per million-lumen hours. The same amount of light from electric lamps now costs only 2 pounds. But today's low-cost illumination still has a dark side. Globally, lighting consumes more electricity than is produced by either hydro or nuclear power and results in CO2 emissions equivalent to two thirds of the world's cars. A standard incandescent lamp may be much more efficient than a tallow candle, but it is far less efficient than a high-pressure sodium lamp. Were inefficient light sources to be replaced by the equivalent efficient ones, global lighting energy demand would be up to 40% less at a lower overall cost. Larger savings still could be realised through the intelligent use of controls, lighting levels and daylight. But achieving efficient lighting is not just a question of technology; it requires policies to transform current practice. This book documents the broad range of policy measures to stimulate efficient lighting that have already been implemented around the world and suggests new ways these could be strengthened to prevent light's labour's from being lost

  11. Advanced lighting guidelines: 1993. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Eley, C.; Tolen, T.M. [Eley Associates, San Francisco, CA (United States); Benya, J.R. [Luminae Souter Lighting Design, San Francisco, CA (United States); Rubinstein, F.; Verderber, R. [Lawrence Berkeley Lab., CA (United States)

    1993-12-31

    The 1993 Advanced Lighting Guidelines document consists of twelve guidelines that provide an overview of specific lighting technologies and design application techniques utilizing energy-efficient lighting practice. Lighting Design Practice assesses energy-efficient lighting strategies, discusses lighting issues, and explains how to obtain quality lighting design and consulting services. Luminaires and Lighting Systems surveys luminaire equipment designed to take advantage of advanced technology lamp products and includes performance tables that allow for accurate estimation of luminaire light output and power input. The additional ten guidelines -- Computer-Aided Lighting Design, Energy-Efficient Fluorescent Ballasts, Full-Size Fluorescent Lamps, Compact Fluorescent Lamps, Tungsten-Halogen Lamps, Metal Halide and HPS Lamps, Daylighting and Lumen Maintenance, Occupant Sensors, Time Scheduling Systems, and Retrofit Control Technologies -- each provide a product technology overview, discuss current products on the lighting equipment market, and provide application techniques. This document is intended for use by electric utility personnel involved in lighting programs, lighting designers, electrical engineers, architects, lighting manufacturers` representatives, and other lighting professionals.

  12. Color tuning in alert macaque V1 assessed with fMRI and single-unit recording shows a bias toward daylight colors.

    Science.gov (United States)

    Lafer-Sousa, Rosa; Liu, Yang O; Lafer-Sousa, Luis; Wiest, Michael C; Conway, Bevil R

    2012-05-01

    Colors defined by the two intermediate directions in color space, "orange-cyan" and "lime-magenta," elicit the same spatiotemporal average response from the two cardinal chromatic channels in the lateral geniculate nucleus (LGN). While we found LGN functional magnetic resonance imaging (fMRI) responses to these pairs of colors were statistically indistinguishable, primary visual cortex (V1) fMRI responses were stronger to orange-cyan. Moreover, linear combinations of single-cell responses to cone-isolating stimuli of V1 cone-opponent cells also yielded stronger predicted responses to orange-cyan over lime-magenta, suggesting these neurons underlie the fMRI result. These observations are consistent with the hypothesis that V1 recombines LGN signals into "higher-order" mechanisms tuned to noncardinal color directions. In light of work showing that natural images and daylight samples are biased toward orange-cyan, our findings further suggest that V1 is adapted to daylight. V1, especially double-opponent cells, may function to extract spatial information from color boundaries correlated with scene-structure cues, such as shadows lit by ambient blue sky juxtaposed with surfaces reflecting sunshine. © 2012 Optical Society of America

  13. Assessment and the feasibility of improving the artificial lighting system in technical services workshop located in the Fourth South Pars Gas Refinery

    OpenAIRE

    masoud shafiee motlagh; Mohsen Aliabadi; Reza Shahidi; Amin Kahani

    2015-01-01

    Background & Objectives: Desirable and ergonomic lighting in the workplaces has a significant impact on the visual effects and improve the efficiency and productivity of employees. This study aims to evaluate the lighting system and feasibility of improving the artificial lighting system for comfort lighting in the workshop of the Fourth South Pars Gas Refinery. Methods: In this descriptive-analytical study, the environmental conditions of the studied workshop were evaluated and the illum...

  14. Cost/effectiveness aspects of road lighting : revised version of Contribution to CIE TC-4.6 Symposium on Measures of Road Lighting Effectiveness, Session II - Road lighting and accidents, Karlsruhe, 5-6 July 1977, SWOV R-77-46.

    NARCIS (Netherlands)

    Flury, F.C.

    1981-01-01

    The common method to determine the effect of road lighting on traffic safety, is to compare accident numbers during daylight and darkness, before and after the measure is taken. This approach ignores the possibility of increased risk of collisions with road side obstacles due to the erection of

  15. Attraction of Chagas disease vectors (Triatominae) to artificial light sources in the canopy of primary Amazon rainforest.

    Science.gov (United States)

    Castro, Marcelo C M; Barrett, Toby V; Santos, Walter S; Abad-Franch, Fernando; Rafael, José A

    2010-12-01

    Adult triatomines occasionally fly into artificially lit premises in Amazonia. This can result in Trypanosoma cruzi transmission to humans either by direct contact or via foodstuff contamination, but the frequency of such behaviour has not been quantified. To address this issue, a light-trap was set 45 m above ground in primary rainforest near Manaus, state of Amazonas, Brazil and operated monthly for three consecutive nights over the course of one year (432 trap-hours). The most commonly caught reduviids were triatomines, including 38 Panstrongylus geniculatus, nine Panstrongylus lignarius, three Panstrongylus rufotuberculatus, five Rhodnius robustus, two Rhodnius pictipes, one Rhodnius amazonicus and 17 Eratyrus mucronatus. Males were collected more frequently than females. The only month without any catches was May. Attraction of most of the known local T. cruzi vectors to artificial light sources is common and year-round in the Amazon rainforest, implying that they may often invade premises built near forest edges and thus become involved in disease transmission. Consequently, effective Chagas disease prevention in Amazonia will require integrating entomological surveillance with the currently used epidemiological surveillance.

  16. Attraction of Chagas disease vectors (Triatominae to artificial light sources in the canopy of primary Amazon rainforest

    Directory of Open Access Journals (Sweden)

    Marcelo CM Castro

    2010-12-01

    Full Text Available Adult triatomines occasionally fly into artificially lit premises in Amazonia. This can result in Trypanosoma cruzi transmission to humans either by direct contact or via foodstuff contamination, but the frequency of such behaviour has not been quantified. To address this issue, a light-trap was set 45 m above ground in primary rainforest near Manaus, state of Amazonas, Brazil and operated monthly for three consecutive nights over the course of one year (432 trap-hours. The most commonly caught reduviids were triatomines, including 38 Panstrongylus geniculatus, nine Panstrongylus lignarius, three Panstrongylus rufotuberculatus, five Rhodnius robustus, two Rhodnius pictipes, one Rhodnius amazonicus and 17 Eratyrus mucronatus. Males were collected more frequently than females. The only month without any catches was May. Attraction of most of the known local T. cruzi vectors to artificial light sources is common and year-round in the Amazon rainforest, implying that they may often invade premises built near forest edges and thus become involved in disease transmission. Consequently, effective Chagas disease prevention in Amazonia will require integrating entomological surveillance with the currently used epidemiological surveillance.

  17. Does Daylight Saving Save Energy? A Meta-Analysis

    OpenAIRE

    Havránek, Tomáš; Herman, Dominik; Irsova, Zuzana

    2016-01-01

    The original rationale for adopting daylight saving time (DST) was energy savings. Modern research studies, however, question the magnitude and even direction of the effect of DST on energy consumption. Representing the first meta-analysis in this literature, we collect 162 estimates from 44 studies and find that the mean reported estimate indicates modest energy savings: 0.34% during the days when DST applies. The literature is not affected by publication bias, but the results vary systemati...

  18. Technical-economic feasibility of orbiting sunlight reflectors

    Science.gov (United States)

    Alferov, Z.; Minin, V.

    1986-02-01

    The use of deflectors in orbit as a means of providing artificial illumination is examined. Considerations of technical and economic feasibility are addressed. Three main areas of application are distinguished: reflecting sunlight onto the surface of the Earth; concentration of the flow of solar energy on an orbiting receiver; and retransmission of optical radiation. The advantages of the artificial Earth illumination application of the orbiting reflector scheme in terms of energy savings in lighting cities, and additional daylight time for critical periods of farming operations are discussed.

  19. Transition into daylight saving time influences the fragmentation of the rest-activity cycle

    Directory of Open Access Journals (Sweden)

    Tuulio-Henriksson Annamari

    2006-01-01

    Full Text Available Abstract Background Daylight saving time is widely adopted. Little is known about its influence on the daily rest-activity cycles. We decided to explore the effects of transition into daylight saving time on the circadian rhythm of activity. Methods We monitored the rest-activity cycles with the use of wrist-worn accelerometer on a sample of ten healthy adults for ten days around the transition into summer time. Identical protocols were carried out on the same individuals in two consecutive years, yielding data on 200 person-days for analysis in this study. Results There was no significant effect on the rest-activity cycle in the sample as a whole. Fragmentation of the rest-activity cycle was enhanced in a subgroup of persons having sleep for eight hours or less (P = 0.04 but reduced in those who preferred to sleep for more than eight hours per night (P = 0.05. The average level of motor activity was increased in persons having the morning preference for daily activity patterns (P = 0.01. Conclusion Transition into daylight saving time may have a disruptive effect on the rest-activity cycle in those healthy adults who are short-sleepers or more of the evening type.

  20. Parametric analysis of parameters for electrical-load forecasting using artificial neural networks

    Science.gov (United States)

    Gerber, William J.; Gonzalez, Avelino J.; Georgiopoulos, Michael

    1997-04-01

    Accurate total system electrical load forecasting is a necessary part of resource management for power generation companies. The better the hourly load forecast, the more closely the power generation assets of the company can be configured to minimize the cost. Automating this process is a profitable goal and neural networks should provide an excellent means of doing the automation. However, prior to developing such a system, the optimal set of input parameters must be determined. The approach of this research was to determine what those inputs should be through a parametric study of potentially good inputs. Input parameters tested were ambient temperature, total electrical load, the day of the week, humidity, dew point temperature, daylight savings time, length of daylight, season, forecast light index and forecast wind velocity. For testing, a limited number of temperatures and total electrical loads were used as a basic reference input parameter set. Most parameters showed some forecasting improvement when added individually to the basic parameter set. Significantly, major improvements were exhibited with the day of the week, dew point temperatures, additional temperatures and loads, forecast light index and forecast wind velocity.

  1. 75 FR 36089 - Payment System Risk Policy; Daylight Overdraft Posting Rules

    Science.gov (United States)

    2010-06-24

    ... FEDERAL RESERVE SYSTEM [OP-1385] Payment System Risk Policy; Daylight Overdraft Posting Rules... Payment System Risk Policy, the Board is announcing posting rules for a new same-day automated clearing... Kirkpatrick, Senior Financial Services Analyst, Payment System Risk (202-452-2796), or Jennifer Davidson...

  2. 78 FR 70046 - Payment System Risk Policy; Daylight Overdraft Posting Rules

    Science.gov (United States)

    2013-11-22

    ... FEDERAL RESERVE SYSTEM [Docket No. OP--1471] Payment System Risk Policy; Daylight Overdraft... Reserve Policy on Payment System Risk (PSR policy) to eliminate certain posting rules to conform with... Services Analyst (202- 452-2404), Division of Reserve Bank Operations and Payment Systems. For users of...

  3. Effect of Window Glazing on Colour Quality of Transmitted Daylight

    Directory of Open Access Journals (Sweden)

    Rajendra Dangol

    2017-12-01

    Full Text Available In this study, the colour quality of the daylight transmitted through different window glazing types is evaluated. The analysis considered four different types of window glazing: laminated, monolithic, coated and applied film glazing ranging in luminous transmittance from around 0.97 to <0.1. The spectral transmittance data of different window glazing types are taken from the International Glazing Data Base (IGDB, which is maintained by Lawrence Berkeley National Laboratories (LBNL. The study showed that the CIE CRI does not always seem to be the suitable method to predict the colour quality of daylight in building for particular situations. However, in the context of this study, the prediction of colour rendering properties of window glazing by other metrics such as Colour Quality Scale (version 9, Memory CRI, Ra,D65 (adjusted CRI metric with D65 as the reference illuminant performed better. For most of the daylit situations inside the building, the chromaticity difference criterion was not met. Judging the colour quality of such situations requires different method.

  4. Artificial LED lighting enhances growth characteristics and total phenolic content of Ocimum basilicum, but variably affects transplant success

    OpenAIRE

    Bantis, Filippos; Ouzounis, Theoharis; Radoglou, Kalliopi

    2016-01-01

    The morphological and phytochemical characteristics of two Ocimum basilicum cultivars (Lettuce Leaf, and Red Rubin-mountain Athos hybrid) under artificial lighting were investigated. Four LED light treatments [AP673L (high red and high red:far-red), G2 (high red and low red:far-red), AP67 (moderate blue and red and low red:far-red), and NS1 (high blue and green, high red:far-red and 1% ultraviolet)] with different colors mixing UV, blue, green, red and far-red, and fluorescent tubes (FL, high...

  5. Contrasting trends in light pollution across Europe based on satellite observed night time lights.

    Science.gov (United States)

    Bennie, Jonathan; Davies, Thomas W; Duffy, James P; Inger, Richard; Gaston, Kevin J

    2014-01-21

    Since the 1970s nighttime satellite images of the Earth from space have provided a striking illustration of the extent of artificial light. Meanwhile, growing awareness of adverse impacts of artificial light at night on scientific astronomy, human health, ecological processes and aesthetic enjoyment of the night sky has led to recognition of light pollution as a significant global environmental issue. Links between economic activity, population growth and artificial light are well documented in rapidly developing regions. Applying a novel method to analysis of satellite images of European nighttime lights over 15 years, we show that while the continental trend is towards increasing brightness, some economically developed regions show more complex patterns with large areas decreasing in observed brightness over this period. This highlights that opportunities exist to constrain and even reduce the environmental impact of artificial light pollution while delivering cost and energy-saving benefits.

  6. The shift to and from daylight savings time and motor vehicle crashes.

    Science.gov (United States)

    Lambe, M; Cummings, P

    2000-07-01

    The objective of the study was to examine whether the shifts to and from daylight savings time in Sweden have short-term effects on the incidence of traffic crashes. A database maintained by the Swedish National Road Administration was used to examine crashes from 1984 through 1995, that occurred on state roads the Monday preceding, the Monday immediately after (index Monday), and the Monday 1 week after the change to daylight savings time in the spring and for the corresponding three Mondays in the autumn. The Mondays 1 week before and after the time changes were taken as representing the expected incidence of crashes. Crash incidence was calculated per 1000 person-years using population estimates for each year of the study. The association between 1 h of possible sleep loss and crash incidence was estimated by the incidence rate ratio from negative binomial regression. The incidence rate ratio was 1.04 (95% CI, 0.92-1.16) for a Monday on which drivers were expected to have had 1 h less sleep, compared with other Mondays. In the spring, the incidence rate ratio for crashes was 1.11 (95% CI, 0.93-1.31) for Mondays after the time change compared to other spring Mondays. The corresponding rate ratio for the fall was 0.98 (95% CI, 0.84-1.15) It was concluded that the shift to and from daylight savings time did not have measurable important immediate effects on crash incidence in Sweden.

  7. 77 FR 22666 - Payment System Risk Policy; Daylight Overdraft Posting Rules

    Science.gov (United States)

    2012-04-17

    ... FEDERAL RESERVE SYSTEM 12 CFR Part 204 [Docket No. OP-1440] Payment System Risk Policy; Daylight.... SUMMARY: The Board of Governors of the Federal Reserve System (Board) has revised its Policy on Payment...), Division of Reserve Bank Operations and Payment Systems. For users of Telecommunications Device for the...

  8. The impact of changing solar screen rotation angle and its opening aspect ratios on Daylight Availability in residential desert buildings

    KAUST Repository

    Sherif, Ahmed H.

    2012-11-01

    In desert sunny clear-sky regions solar penetration can become excessive. This can cause non-uniform daylight distribution, glare and high solar heat gain, affecting both visual and thermal comfort. Shading devices, such as solar screens, were usually used to diffuse and prevent direct solar penetration into spaces. This paper investigates the impact of changing solar screen axial rotation angle and screen opening aspect ratio on daylighting performance in a typical residential living room space under the desert sunny clear-sky. The larger aim is to arrive at efficient solar screen designs that suit the different orientations.The study was divided into three consecutive phases. In phase one, the effect of the two parameters on Daylight Availability was tested. The solar screen was axially rotated by three different angles at 10° increments. Also, the aspect ratio of the screen opening in both horizontal and vertical directions was changed systematically. Simulation was conducted using the annual Daylight Dynamic Performance Metrics (DDPMs). In phase two, the Annual Daylight Glare Probability (DGP) metric was evaluated for the cases that were found adequate in phase one. In the third phase, the annual solar energy transmittance through the screen was calculated for the cases that achieved acceptable performance in the two previous phases in order to identify the more energy efficient screens.Solar screens with openings having horizontal aspect ratios were found to be the most effective, while those with vertical aspect ratios were achieved the lowest performance. In the North orientation, since almost all the cases that were tested in this research provided acceptable daylighting performance, the designer now have a variety of options to choose from. Preference should be given to screen openings of horizontal aspect ratios, especially the 12:1 and 18:1 (H:V) screens that achieved the best performance where 92% of the space was " daylit" in comparison with only 53

  9. Experimental illumination of natural habitat--an experimental set-up to assess the direct and indirect ecological consequences of artificial light of different spectral composition.

    Science.gov (United States)

    Spoelstra, Kamiel; van Grunsven, Roy H A; Donners, Maurice; Gienapp, Phillip; Huigens, Martinus E; Slaterus, Roy; Berendse, Frank; Visser, Marcel E; Veenendaal, Elmar

    2015-05-05

    Artificial night-time illumination of natural habitats has increased dramatically over the past few decades. Generally, studies that assess the impact of artificial light on various species in the wild make use of existing illumination and are therefore correlative. Moreover, studies mostly focus on short-term consequences at the individual level, rather than long-term consequences at the population and community level-thereby ignoring possible unknown cascading effects in ecosystems. The recent change to LED lighting has opened up the exciting possibility to use light with a custom spectral composition, thereby potentially reducing the negative impact of artificial light. We describe here a large-scale, ecosystem-wide study where we experimentally illuminate forest-edge habitat with different spectral composition, replicated eight times. Monitoring of species is being performed according to rigid protocols, in part using a citizen-science-based approach, and automated where possible. Simultaneously, we specifically look at alterations in behaviour, such as changes in activity, and daily and seasonal timing. In our set-up, we have so far observed that experimental lights facilitate foraging activity of pipistrelle bats, suppress activity of wood mice and have effects on birds at the community level, which vary with spectral composition. Thus far, we have not observed effects on moth populations, but these and many other effects may surface only after a longer period of time. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  10. Simple tool to evaluate the impact of daylight on building energy consumption

    DEFF Research Database (Denmark)

    Hviid, Christian Anker; Nielsen, Toke Rammer; Svendsen, Svend

    2008-01-01

    This paper presents a simple building simulation tool for integrated daylight and thermal analysis. The tool is capable of importing the thermal and visual properties for different glazings and shading positions from the Window Information System (WIS) program. Radiosity methodology is used...

  11. Experiences collected with a daylight system

    International Nuclear Information System (INIS)

    Krueger, P.

    1981-01-01

    The Kodak Daylight System is space-saving. It consists of the Kodak-X-Omat cassette, the identification camera and the loading and reloading device (cassette multiloader). All three units of this system are notable for extremely safe operation. Handling is simple and easily appreciated. All brands of film can be used. The data window in the cassette is too large; in some cases, important sections of the image can be covered up by the window. Automatic loading and reloading considerably reduces solling of the cassette, which is otherwise common, and also reduces abrasion of the intensifying screen. Introduction of this system has had a beneficial effect on overall working and has been welcomed by all concerned as a contribution towards facilitating routine work. (orig.) [de

  12. Effects of daylight-saving time changes on stock market volatility: a comment.

    Science.gov (United States)

    Kamstra, Mark J; Kramer, Lisa A; Levi, Maurice D

    2010-12-01

    In a recent article in this journal, Berument, Dogan, and Onar (2010) challenged the existence of the previously documented daylight-saving effect. Kamstra, Kramer, and Levi's original finding (2000) was that average stock market returns on Mondays following time changes are economically and statistically significantly lower than typical Monday returns. Kamstra, et al. hypothesized that the effect may arise due to heightened anxiety or risk aversion on the part of market participants after they experience a 1-hr. disruption in their sleep habits, in accordance with prior findings in the psychology literature linking sleep desynchronosis with anxiety. Berument, et al. replicated the original findings using ordinary least squares estimation, but when they modeled the mean of returns using a method prone to producing biased estimates, they obtained puzzling results. The analysis here, based on standard, unbiased modeling techniques, shows that the daylight-saving effect remains intact in the U.S.

  13. Exploring the Impact of Natural Light Exposure on Sleep of Healthy Older Adults: A Field Study

    Directory of Open Access Journals (Sweden)

    Mariëlle P. J. Aarts

    2018-05-01

    Full Text Available Studies among people with dementia demonstrated that the sleep quality and rhythm improves significantly when people are exposed to ambient bright light. Since almost half of the healthy older people also indicate to suffer from chronic sleep disorders, the question arises whether ambient bright light can be beneficial to healthy older people. Particularly the effect on sleep/wake rhythm in relation to the exposure to natural light is the focus. It was hypothesised that the sleep quality would be worse in winter due to a lower daylight dose than in summer due to the lower illuminance and exposure duration. A field study was conducted to examine the relationship between daylight exposure and sleep quality in 14 healthy older adults living independently in their own dwellings in the Netherlands. All participants were asked to take part of the study both during the summer period as well as during the winter period. Therefore, they had to wear an actigraph for five consecutive days which measured sleep, activity and light exposure. Results confirmed that people were significantly longer exposed to high illumination levels (>1000 lx in summer than in winter. Sleep quality measures, however, did not differ significantly between summer and winter. A significant, positive correlation was found between exposure duration to high illuminance from daylight during the day and the sleep efficiency the following night in summer, implying that being exposed to high illuminance for a longer time period has a positive effect on sleep efficiency for the individual data. There was also a tendency of less frequent napping in case of longer exposure duration to light for both seasons. Sleep quality does not differ between summer and winter but is related to the duration of the exposure to bright light the day prior to the night.

  14. Efficiency figures and rating methods are essential for the design and implementation of energetically optimized general lighting systems; Neue Effizienzkennzahlen fuer Beleuchtungssysteme in Gebaeuden

    Energy Technology Data Exchange (ETDEWEB)

    Boer, Jan de [Fraunhofer-Institut fuer Bauphysik, Stuttgart (Germany); Aydinli, Sirri [Technische Universitaet Berlin (Germany); Cornelius, Wolfgang [Fachverband Tageslicht und Rauchschutz e.V. (FVLR), Detmold (Germany); Minnerup, Joerg [TRILUX GmbH + Co KG, Arnsberg (Germany); Schornick, Dieter [ZVEI - Zentralverband Elektrotechnik-und Elektronikindustrie e.V., Frankfurt (Germany); Wershoven, Ralf [ERCO Leuchten GmbH, Luedenscheid (Germany); Jakobiak, Roman

    2011-08-15

    Over the last years - on national as well as on international level - integrated rating methods (daylighting as well as artificial lighting) have been developed and transferred into practice, the later was fostered by integration into the corresponding standards (DIN V 18599-4, EN 15193-1) and the methods being referenced by national regulations like the German Building Energy Conservation Ordinance (EnEV). Emerging new lighting technologies und requirements to further improve the rating procedure pushed the development of additional new efficiency figures. The concept of expense factors has long been available and applied e.g. in the domain of heating systems. Now, as derived in this publication, it is as well assigned to indoor lighting systems. Therefore, from now on, it will be possible to differentiate lighting installations by their net energy and by their final energy demand. The efficiency of the lighting system itself can be described as function of the expense factor. Currently several new LED-products (lamps and luminaires) are introduced to the market of general lighting. In order to enable practitioners to energetically rate these products, the diversity of products has been structured into classes with assigned efficiency figures. Lighting appliances strongly depend on how the considered zone is used. To provide practioners with exemplary solutions (type of lighting system, facade composition, lighting control) a collection of typical appliances as function of zone usage has been established. This collection has been matched to the structure of the German DIN V 18599 standards.

  15. Control of the lighting system using a genetic algorithm

    Directory of Open Access Journals (Sweden)

    Čongradac Velimir D.

    2012-01-01

    Full Text Available The manufacturing, distribution and use of electricity are of fundamental importance for the social life and they have the biggest influence on the environment associated with any human activity. The energy needed for building lighting makes up 20-40% of the total consumption. This paper displays the development of the mathematical model and genetic algorithm for the control of dimmable lighting on problems of regulating the level of internal lighting and increase of energetic efficiency using daylight. A series of experiments using the optimization algorithm on the realized model confirmed very high savings in electricity consumption.

  16. Spanish-Portuguese consensus statement on use of daylight-mediated photodynamic therapy with methyl aminolevulinate in the treatment of actinic keratosis.

    Science.gov (United States)

    Gilaberte, Y; Aguilar, M; Almagro, M; Correia, O; Guillén, C; Harto, A; Pérez-García, B; Pérez-Pérez, L; Redondo, P; Sánchez-Carpintero, I; Serra-Guillén, C; Valladares, L M

    2015-10-01

    Daylight-mediated photodynamic therapy (PDT) is a new type of PDT that is as effective as conventional PDT in grade 1 and 2 actinic keratosis but with fewer adverse effects, resulting in greater efficiency. The climatic conditions in the Iberian Peninsula require an appropriately adapted consensus protocol. We describe a protocol for the treatment of grade 1 and 2 actinic keratosis with daylight-mediated PDT and methyl aminolevulinate (MAL) adapted to the epidemiological and clinical characteristics of Spanish and Portuguese patients and the climatic conditions of both countries. Twelve dermatologists from different parts of Spain and Portugal with experience in the treatment of actinic keratosis with PDT convened to draft a consensus statement for daylight-mediated PDT with MAL in these countries. Based on a literature review and their own clinical experience, the group developed a recommended protocol. According to the recommendations adopted, patients with multiple grade 1 and 2 lesions, particularly those at risk of developing cancer, are candidates for this type of therapy. Daylight-mediated PDT can be administered throughout the year, although it is not indicated at temperatures below 10°C or at excessively high temperatures. Likewise, therapy should not be administered when it is raining, snowing, or foggy. The procedure is simple, requiring application of a sunscreen with a protection factor of at least 30 based exclusively on organic filters, appropriate preparation of the lesions, application of MAL without occlusion, and activation in daylight for 2hours. This consensus statement represents a practical and detailed guideline to achieve maximum effectiveness of daylight-mediated PDT with MAL in Spain and Portugal with minimal adverse effects. Copyright © 2015 Elsevier España, S.L.U. and AEDV. All rights reserved.

  17. Impact of solar shading on daylight quality. Measurements in experimental office rooms

    Energy Technology Data Exchange (ETDEWEB)

    Dubois, M.C.

    2001-07-01

    The impact of ten solar shading screens and one venetian blind on daylight quality was studied through measurements in two south-oriented experimental office rooms. The daylight quality was assessed by considering five performance indicators: the daylight factor, the work plane illuminance, the illuminance uniformity on the work plane, the absolute luminance in the field of view and the luminance ratios between the paper task, the walls and the VDT screen. The measurements were carried out under perfect sunny conditions and overcast conditions. The results show that the shading devices can be divided into three distinct groups. Group 1 consists of all dark-coloured screens; Group 2 includes the closed venetian blind while Group 3 includes the white screens and the horizontal venetian blind. The devices of Group 1 produced unacceptably low work plane illuminance and vertical luminance values which resulted in unsuitable luminance ratios between the task, the walls and VDT screen. However, these devices reduced the luminance of the window (sky) to acceptable levels. The devices of Group 3 did not prevent high window luminance but yielded higher levels of work plane illuminance and inner wall luminance, which makes them suitable for traditional paper tasks. They also generated high wall luminance values which resulted in a number of unacceptable luminance ratios between the task, walls and VDT screen. The closed venetian blind (Group 2) was the only device which scored well on all performance indicators considered. It provided ideal illuminance levels for paper and VDT tasks and resulted in favourable wall luminance values for computer work.

  18. Measurement and Verification of Energy Savings and Performance from Advanced Lighting Controls

    Energy Technology Data Exchange (ETDEWEB)

    PNNL

    2016-02-21

    This document provides a framework for measurement and verification (M&V) of energy savings, performance, and user satisfaction from lighting retrofit projects involving occupancy-sensor-based, daylighting, and/or other types of automatic lighting. It was developed to provide site owners, contractors, and other involved organizations with the essential elements of a robust M&V plan for retrofit projects and to assist in developing specific project M&V plans.

  19. Effects of daylight-saving time changes on stock market returns and stock market volatility: rebuttal.

    Science.gov (United States)

    Kamstra, Mark J; Kramer, Lisa A; Levi, Maurice D

    2013-02-01

    In a 2011 reply to our 2010 comment in this journal, Berument and Dogen maintained their challenge to the existence of the negative daylight-saving effect in stock returns reported by Kamstra, Kramer, and Levi in 2000. Unfortunately, in their reply, Berument and Dogen ignored all of the points raised in the comment, failing even to cite the Kamstra, et al. comment. Berument and Dogen continued to use inappropriate estimation techniques, over-parameterized models, and low-power tests and perhaps most surprisingly even failed to replicate results they themselves reported in their previous paper, written by Berument, Dogen, and Onar in 2010. The findings reported by Berument and Dogen, as well as by Berument, Dogen, and Onar, are neither well-supported nor well-reasoned. We maintain our original objections to their analysis, highlight new serious empirical and theoretical problems, and emphasize that there remains statistically significant evidence of an economically large negative daylight-saving effect in U.S. stock returns. The issues raised in this rebuttal extend beyond the daylight-saving effect itself, touching on methodological points that arise more generally when deciding how to model financial returns data.

  20. Simple tool to evaluate the impact of daylight on building energy consumption

    DEFF Research Database (Denmark)

    Hviid, Christian Anker; Nielsen, Toke Rammer; Svendsen, Svend

    2008-01-01

    This paper presents a simple building simulation tool for integrated daylight and thermal analysis. The tool is capable of importing the thermal and visual properties for different glazings and shading positions from the Window Information System (WIS) program. A coupled ray-tracing and radiosity...

  1. Electrical lighting for improved wellbeing of elderly citizens

    DEFF Research Database (Denmark)

    Markvart, Jakob; Agnes Sander, Birgit; Kessel, Line

    2015-01-01

    Healthy elderly citizens living in their own homes may benefit from having replaced their existing indoor lighting with a lighting being superior in stimulating their circadian rhythm to improve sleep and general wellbeing. This was hypothesised in the presented study. We replaced the existing...... indoor lighting in the main living room of elderly citizens in 20 uniform private houses in a suburb of Copenhagen. In a randomized cross-over design 29 healthy participants over 65 years were exposed over 3 weeks to blue-enriched and 3 weeks to blue-deprived light with similar corneal photopic...... illuminances from 8 am to 13 pm. The two light epochs were separated by one week neutral indoor light. Daylight factors were measured for each of the houses. The pre-experimental lighting conditions were documented by pictures and the experimental light was measured on location using portable photometers...

  2. Design and development of an improved traffic light control system using hybrid lighting system

    Directory of Open Access Journals (Sweden)

    Michael Osigbemeh

    2017-02-01

    Full Text Available The deployment of light emitting diodes (LEDs based traffic system control created the problem of dim displays when ambient light is similar to traffic lights. It causes some drivers' disability of seeing and obeying traffic signs. This makes drivers violate traffic rules. In this paper, an attempt to use hybrid lighting technology to mitigate this problem was developed. Incandescent lightings with deployed halogen bulbs provided an instantaneous source of highly efficacious illumination which is brighter than the drivers' ambient lights (both daylight, electrical lights and their reflections, which can help drivers get access to enough warning and help them initiate traffic safety warning as necessary. The halogen lightings also offered the required high current draw needed in electrical circuitry to help brighten the LED displays. The problem of heat generated was eliminated by aerating the T-junction traffic light control unit designed for this technology. The result of hybrid lighting system design was found to be high luminosity and capability of gaining driver attention in real-time. It also allowed enhanced sign's image detection and processing for smart based technologies by providing the “light punch” needed for a wide range of visual concerns.

  3. Balancing the daylighting and energy performance of solar screens in residential desert buildings: Examination of screen axial rotation and opening aspect ratio

    KAUST Repository

    Sabry, Hanan

    2014-05-01

    Solar screens are typically used to control solar access into building spaces. They proved their usefulness in improving the daylighting and energy performance of buildings in the hot arid desert environments which are endowed with abundance of clear skies.The daylighting and energy performance of solar screens is affected by many parameters. These include screen perforation, depth, reflectivity and color, aspect ratio of openings, shape, tilt angle and rotation. Changing some of these parameters can improve the daylighting performance drastically. However, this can result in increased energy consumption. A balanced solution must be sought, where acceptable daylighting performance would be achieved at minimum energy consumption.This paper aims at defining solar screen designs that achieve visual comfort and at the same time minimum energy consumption in residential desert settings. The study focused on the effect of changing the solar screen axial rotation and the aspect ratio of its openings under the desert clear-sky. The individual and combined effects of changing these parameters were studied.Results of this study demonstrated that a non-rotated solar screen that has wide horizontal openings (aspect ratio of 18:1) proved to be successful in the north and south orientations. Its performance in the east/west orientations was also superior. In contrast, the screen that was rotated along its vertical axis while having small size openings (aspect ratio of 1:1) proved to be more successful in the east/west orientations. Its performance in the north orientation was also good. These solutions enhanced daylighting performance, while maintaining the energy consumption at a minimum.Moreover, it was observed that combining two screen parameters which proved useful in previous studies on daylighting or thermal performance does not add up to better solutions. The combined solutions that were tested in this study did not prove successful in satisfying daylighting and thermal

  4. Does light attract piglets to the creep area?

    Science.gov (United States)

    Larsen, M L V; Pedersen, L J

    2015-06-01

    Hypothermia, experienced by piglets, has been related to piglet deaths and high and early use of a heated creep area is considered important to prevent hypothermia. The aims of the present study were to investigate how a newly invented radiant heat source, eHeat, would affect piglets' use of the creep area and whether light in the creep area works as an attractant on piglets. A total of 39 sows, divided between two batches, were randomly distributed to three heat source treatments: (1) standard infrared heat lamp (CONT, n=19), (2) eHeat with light (EL, n=10) and (3) eHeat without light (ENL, n=10). Recordings of piglets' use of the creep area were made as scan sampling every 10 min for 3 h during two periods, one in daylight (0900 to 1200 h) and one in darkness (2100 to 2400 h), on day 1, 2, 3, 7, 14 and 21 postpartum. On the same days, piglets were weighted. Results showed an interaction between treatment and observation period (Pcreep area during darkness compared with daylight for CONT and EL litters, but not for ENL litters. Piglets average daily weight gain was not affected by treatment, but was positively correlated with piglets' birth weight and was lower in batch 1 compared with batch 2. Seen from the present results, neither eHeat nor light worked as an attractant on piglets; in contrast, piglets preferred to sleep in the dark and it would therefore be recommended to turn off the light in the creep area during darkness. Heating up the creep area without light can be accomplished by using a radiant heat source such as eHeat in contrast to the normally used light-emitting infrared heat lamp.

  5. Sustainable building with closed cavity facades. Top energy efficiency and more daylight; Nachhaltig bauen mit Closed Cavity Fassaden. Hoechste Energieeffizienz und mehr Tageslicht

    Energy Technology Data Exchange (ETDEWEB)

    Rudolf, Bernhard

    2012-08-15

    Facades have a key function within the sustainable construction since the energy conservation significantly depends on the building envelope. Beside an enhanced energy efficiency, the Green Building shall offer an improved utilization of day-lighting and comfortable indoor climatic conditions. Here, the innovative Closed Cavity Facade new standards. The former 'Poseidon building' in Frankfurt/Main (Federal Republic of Germany) and the multi-storey building of the Roche company in Basel (Switzerland) are equipped with this facade. The energy costs, operational costs as well as the maintenance costs are reduced sustainably using this closed bivalved facade.

  6. Influence of daylight on the fate of silver and zinc oxide nanoparticles in natural aquatic environments.

    Science.gov (United States)

    Odzak, Niksa; Kistler, David; Sigg, Laura

    2017-07-01

    Nanoparticles, such as silver (Ag-NP) and zinc oxide (ZnO-NP), are increasingly used in many consumer products. These nanoparticles (NPs) will likely be exposed to the aquatic environment (rain, river, lake water) and to light (visible and UV) in the products where they are applied, or after those products are discharged. Dissolution of Ag-NP and ZnO-NP is an important process because the dissolved Ag + and Zn 2+ are readily available and toxic for aquatic organisms. The objective of this study was to investigate the role of daylight (UV and visible) for the fate of engineered Ag-NP and ZnO-NPs in different types of natural waters. Ag-NP and ZnO-NP were exposed to rainwater, river Rhine, and lake waters (Greifen, Lucerne, Cristallina, Gruère) under different light conditions (no light, UV 300-400 nm and visible light 400-700 nm) for up to 8 days. Stronger agglomeration of Ag-NP was observed in the waters with higher ionic strength in comparison to those with lower ionic strength. Visible light tended to increase the dissolution of Ag-NP under most natural water conditions in comparison to dark conditions, whereas UV-light led to decreased dissolved Ag + after longer exposure time. These effects illustrate the dynamic interactions of Ag-NP with light, which may lead both to increased oxidation and to increased reduction of Ag + by organic compounds under UV-light. In the case of ZnO-NP, agglomeration occurred at higher ionic strength, but the effects of pH were predominant for dissolution, which occurred up to concentrations close to the solubility limit of ZnO(s) at pH around 8.2 and to nearly complete dissolution of ZnO-NP at lower pH (pH 4.8-6.5), with both visible and UV-light facilitating dissolution. This study thus shows that light conditions play an important role in the dissolution processes of nanoparticles. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. The new world atlas of artificial night sky brightness.

    Science.gov (United States)

    Falchi, Fabio; Cinzano, Pierantonio; Duriscoe, Dan; Kyba, Christopher C M; Elvidge, Christopher D; Baugh, Kimberly; Portnov, Boris A; Rybnikova, Nataliya A; Furgoni, Riccardo

    2016-06-01

    Artificial lights raise night sky luminance, creating the most visible effect of light pollution-artificial skyglow. Despite the increasing interest among scientists in fields such as ecology, astronomy, health care, and land-use planning, light pollution lacks a current quantification of its magnitude on a global scale. To overcome this, we present the world atlas of artificial sky luminance, computed with our light pollution propagation software using new high-resolution satellite data and new precision sky brightness measurements. This atlas shows that more than 80% of the world and more than 99% of the U.S. and European populations live under light-polluted skies. The Milky Way is hidden from more than one-third of humanity, including 60% of Europeans and nearly 80% of North Americans. Moreover, 23% of the world's land surfaces between 75°N and 60°S, 88% of Europe, and almost half of the United States experience light-polluted nights.

  8. Light's labour's lost - policies for energy-efficient lighting

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-06-29

    When William Shakepeare wrote Love's Labour's Lost he would have used light from tallow candles at a cost (today) of 12,000 British pounds per million-lumen hours. The same amount of light from electric lamps now costs only 2 pounds! But today's low-cost illumination still has a dark side. Globally, lighting consumes more electricity than is produced by either hydro or nuclear power and results in CO2 emissions equivalent to two thirds of the world's cars. A standard incandescent lamp may be much more efficient than a tallow candle, but it is far less efficient than a high-pressure sodium lamp. Were inefficient light sources to be replaced by the equivalent efficient ones, global lighting energy demand would be up to 40% less at a lower overall cost. Larger savings still could be realised through the intelligent use of controls, lighting levels and daylight. But achieving efficient lighting is not just a question of technology; it requires policies to transform current practice. This book documents the broad range of policy measures to stimulate efficient lighting that have already been implemented around the world and suggests new ways these could be strengthened to prevent light's labour's from being lost.

  9. An investigation into UV light exposure as an experimental model for artificial aging on tensile strength and force delivery of elastomeric chain.

    Science.gov (United States)

    Wahab, Siti Waznah; Bister, Dirk; Sherriff, Martyn

    2014-02-01

    This study investigated the effect of ultraviolet type A light (UVA) exposure on the tensile properties of elastomeric chain. UVA light exposure was used as model for artificial aging, simulating prolonged storage of elastomeric chain. Tensile strength (n = 60) was measured after exposing Ormco, Forestadent and 3M chains to UVA light for 0, 2, 3, and 4 weeks. Force decay was measured (n = 60) using chain exposed for 5, 10, and 14 days. The chains were subsequently stretched at a constant distance and the resulting forces measured at 0, 1, 24 hours and 7, 14, 21, and 28 days. This test simulated a clinical scenario of pre-stretching and subsequent shortening of elastomeric chain. Tensile strength had statistically significant difference and was directly related to the duration of ultraviolet (UV) light exposure. Forestadent chain, which had the second highest value for the 'as received' product, showed the most consistent values over time with the lowest degradation. Ormco showed the lowest values for 'as received' as well as after UV exposure; 3M chain had the highest loss of tensile strength. Force decay was also significantly different. UV light exposure of 10 days or more appears to mark a 'watershed' between products: 3M had most survivors, Forestadent chain had some survivors, depending on the time the chain was stretched for. None of the Ormco product survived UV light exposure for more than 5 days. UVA light exposure may be used as a model for artificial aging as it reduces force delivery and tensile strength of exposed chains.

  10. Design and Analysis of Hybrid Solar Lighting and Full-Spectrum Solar Energy Systems

    International Nuclear Information System (INIS)

    Muhs, J.D.

    2001-01-01

    This paper describes a systems-level design and analysis of a new approach for improving the energy efficiency and affordability of solar energy in buildings, namely, hybrid solar lighting and full-spectrum solar energy systems. By using different portions of the solar spectrum simultaneously for multiple end-use applications in buildings, the proposed system offers unique advantages over other alternatives for using sunlight to displace electricity (conventional topside daylighting and solar technologies). Our preliminary work indicates that hybrid solar lighting, a method of collecting and distributing direct sunlight for lighting purposes, will alleviate many of the problems with passive daylighting systems of today, such as spatial and temporal variability, glare, excess illumination, cost, and energy efficiency. Similarly, our work suggests that the most appropriate use of the visible portion of direct, nondiffuse sunlight from an energy-savings perspective is to displace electric light rather than generate electricity. Early estimates detailed in this paper suggest an anticipated system cost of well under$2.0/Wp and 5-11(cents)/kWh for displaced and generated electricity in single-story commercial building applications. Based on a number of factors discussed in the paper, including sunlight availability, building use scenarios, time-of-day electric utility rates, cost, and efficacy of the displaced electric lights, the simple payback of this approach in many applications could eventually be well under 5 years

  11. Evaluating potential spectral impacts of various artificial lights on melatonin suppression, photosynthesis, and star visibility.

    Directory of Open Access Journals (Sweden)

    Martin Aubé

    Full Text Available Artificial light at night can be harmful to the environment, and interferes with fauna and flora, star visibility, and human health. To estimate the relative impact of a lighting device, its radiant power, angular photometry and detailed spectral power distribution have to be considered. In this paper we focus on the spectral power distribution. While specific spectral characteristics can be considered harmful during the night, they can be considered advantageous during the day. As an example, while blue-rich Metal Halide lamps can be problematic for human health, star visibility and vegetation photosynthesis during the night, they can be highly appropriate during the day for plant growth and light therapy. In this paper we propose three new indices to characterize lamp spectra. These indices have been designed to allow a quick estimation of the potential impact of a lamp spectrum on melatonin suppression, photosynthesis, and star visibility. We used these new indices to compare various lighting technologies objectively. We also considered the transformation of such indices according to the propagation of light into the atmosphere as a function of distance to the observer. Among other results, we found that low pressure sodium, phosphor-converted amber light emitting diodes (LED and LED 2700 K lamps filtered with the new Ledtech's Equilib filter showed a lower or equivalent potential impact on melatonin suppression and star visibility in comparison to high pressure sodium lamps. Low pressure sodium, LED 5000 K-filtered and LED 2700 K-filtered lamps had a lower impact on photosynthesis than did high pressure sodium lamps. Finally, we propose these indices as new standards for the lighting industry to be used in characterizing their lighting technologies. We hope that their use will favor the design of new environmentally and health-friendly lighting technologies.

  12. Light contamination

    International Nuclear Information System (INIS)

    Cepeda Pena, William Enrique

    1998-01-01

    The article tries on the wrong use of the artificial light, of the main problems of the light contamination, dispersion of the light, noxious effects of the light contamination, ecological effects, effects on the man's biological rhythm, economic effects and effects about the civic and vial security, among other topics

  13. Application of remote source lighting system in different layouts of enclosed lift lobbies in highrise residential building of central core design

    Energy Technology Data Exchange (ETDEWEB)

    Wong, I.; Yang, H.X. [Hong Kong Polytechnic Univ., Hung Hom, Hong Kong (China). Dept. of Building Services, Renewable Energy Research Group

    2010-07-01

    This paper reported on a simulation study that explored a new building philosophy that optimizes solar energy to minimize reliance on fossil fuels and to design energy conscious buildings that minimize the energy needed for lighting and cooling. The viability of applying a remote source lighting (RSL) system to transmit daylight into central core lobbies in high-rise residential buildings in Hong Kong was demonstrated. These lobbies are usually enclosed without any windows, thus requiring electric lighting to be switched on 24 hours continuously, consuming non-renewable energy in most cases. In this study, the RSL system was composed of small diameter light pipes and optic fibers. The system transports daylight from the exterior to illuminate the enclosed lobbies. The simulation was conducted to analyze and compare the light transmission efficiency when applying the RSL system to different layouts of the lift lobbies. It was concluded that the efficiency of the RSL system is governed by the length and number of turns in the lobby. 13 refs., 12 figs.

  14. Evaluating the Influence of Road Lighting on Traffic Safety at Accesses Using An Artificial Neural Network.

    Science.gov (United States)

    Xu, Yueru; Ye, Zhirui; Wang, Yuan; Wang, Chao; Sun, Cuicui

    2018-05-18

    This paper focuses on the effect of road lighting on road safety at accesses and tries to quantitatively analyze the relationship between road lighting and road safety. An Artificial Neural Network (ANN) was applied in this study. This method is one of the most popular machine-learning methods in recent years and does not require any pre-defined assumptions. This method was applied using field data collected from ten road segments in Nanjing, Jiangsu Province, China. The results show that the impact of road lighting on road safety at accesses is significant. In addition, road lighting has greater influence when vehicle speeds are higher or the number of lanes is larger. A threshold illuminance was also found in this paper, and the results show that the safety level at accesses will become stable when reaching this value. The improvement of illuminance can decrease the speed variation among vehicles and improve the safety level. In addition, high-grade roads need better illuminance at accesses. A threshold value can also be obtained based on related variables and used to develop scientific guidelines for traffic management organizations.

  15. Experience-Dependent Color Constancy in Guppies (Poecilia reticulata

    Directory of Open Access Journals (Sweden)

    I. E. Intskirveli

    2002-01-01

    Full Text Available We investigated the ability to recognize the color of surfaces in fish (Poecilia reticulata, bred from birth in conditions of artificial light with constant spectral content. The capacity for color constancy significantly deteriorated when compared that to the control group. Further alteration of lighting conditions and transfer into natural daylight conditions restored the suppressed function to its normal level. We suggest that the color constancy function belongs in the visual system-response functions, the full development of which requires the accumulation of individual visual experience.

  16. Influence of light intensity and spectral composition of artificial light at night on melatonin rhythm and mRNA expression of gonadotropins in roach Rutilus rutilus.

    Science.gov (United States)

    Brüning, Anika; Hölker, Franz; Franke, Steffen; Kleiner, Wibke; Kloas, Werner

    2018-02-01

    In this study we investigated the influence of artificial light at night (ALAN) of different intensities (0, 1, 10, 100 lx) and different colours (blue, green, red) on the daily melatonin rhythm and mRNA expression of gonadotropins in roach Rutilus rutilus, a ubiquitous cyprinid, which occur in standing and moderately flowing freshwater habitats of central Europe. Melatonin concentrations were significantly lowered under nocturnal white light already at 1 lx. Low intensity blue, green and red ALAN lowered the melatonin levels significantly in comparison to a dark control. We conclude that ALAN can disturb melatonin rhythms in roach at very low intensities and at different wavelengths and thus light pollution in urban waters has the potential to impact biological rhythms in fish. However, mRNA expression of gonadotropins was not affected by ALAN during the period of the experiments. Thus, suspected implications of ALAN on reproduction of roach could not be substantiated.

  17. Design methodology and criteria for daylight and thermal comfort in nearly-zero energy office buildings in Nordic climate

    DEFF Research Database (Denmark)

    Karlsen, Line Røseth

    The objective of this PhD thesis was to arrange for an integrated building design with respect to thermal comfort, daylighting and energy use, applicable for office buildings in Nordic climate. In order to achieve this, it is suggested that modelling of mean radiant temperature (MRT) should...... into the simulation tool IDA ICE. Furthermore, the control of solar shading is given attention, since it is a crucial link between the thermal and daylighting performance. The thesis presents results of an occupant survey with 46 subjects, which was carried out to investigate occupants’ preferences towards...

  18. Lighting and public health.

    NARCIS (Netherlands)

    Ierland, J. van & Schreuder, D.A.

    1969-01-01

    The following topics; are discussed with respect to public health: - the effect of visible and ultraviolet radiation upon man. - vision with respect to lighting. interior lighting. - artificial lighting of work environments. - day light and windows. - recommendations for lighting. public lighting. -

  19. Porphyrin and fullerene-based artificial photosynthetic materials for photovoltaics

    International Nuclear Information System (INIS)

    Imahori, Hiroshi; Kashiwagi, Yukiyasu; Hasobe, Taku; Kimura, Makoto; Hanada, Takeshi; Nishimura, Yoshinobu; Yamazaki, Iwao; Araki, Yasuyuki; Ito, Osamu; Fukuzumi, Shunichi

    2004-01-01

    We have developed artificial photosynthetic systems in which porphyrins and fullerenes are self-assembled as building blocks into nanostructured molecular light-harvesting materials and photovoltaic devices. Multistep electron transfer strategy has been combined with our finding that porphyrin and fullerene systems have small reorganization energies, which are suitable for the construction of light energy conversion systems as well as artificial photosynthetic models. Highly efficient photosynthetic electron transfer reactions have been realized at ITO electrodes modified with self-assembled monolayers of porphyrin oligomers as well as porphyrin-fullerene linked systems. Porphyrin-modified gold nanoclusters have been found to have potential as artificial photosynthetic materials. These results provide basic information for the development of nanostructured artificial photosynthetic systems

  20. Daylight Design of Office Buildings: Optimisation of External Solar Shadings by Using Combined Simulation Methods

    Directory of Open Access Journals (Sweden)

    Javier González

    2015-05-01

    Full Text Available Integrating daylight and energy performance with optimization into the design process has always been a challenge for designers. Most of the building environmental performance simulation tools require a considerable amount of time and iterations for achieving accurate results. Moreover the combination of daylight and energy performances has always been an issue, as different software packages are needed to perform detailed calculations. A simplified method to overcome both issues using recent advances in software integration is explored here. As a case study; the optimization of external shadings in a typical office space in Australia is presented. Results are compared against common solutions adopted as industry standard practices. Visual comfort and energy efficiency are analysed in an integrated approach. The DIVA (Design, Iterate, Validate and Adapt plug-in for Rhinoceros/Grasshopper software is used as the main tool, given its ability to effectively calculate daylight metrics (using the Radiance/Daysim engine and energy consumption (using the EnergyPlus engine. The optimization process is carried out parametrically controlling the shadings’ geometries. Genetic Algorithms (GA embedded in the evolutionary solver Galapagos are adopted in order to achieve close to optimum results by controlling iteration parameters. The optimized result, in comparison with conventional design techniques, reveals significant enhancement of comfort levels and energy efficiency. Benefits and drawbacks of the proposed strategy are then discussed.

  1. The characterisation of the daylighting properties of special glazings and solar shading devices

    NARCIS (Netherlands)

    Dijk, H.A.L. van; Bakker, L.G.

    1998-01-01

    Within the EU DGXII R&D Programme JOULE a project, called REVIS. started in 1998 and will be completed within 2.5 years, with the objective to develop detailed daylight product information of novel products of glazings and solar shading devices. This involves a test procedure, definition of product

  2. Light redirecting system using sine-wave based panels for dense urban areas

    Science.gov (United States)

    Mohamed, Mohamed W. N.; Mashaly, Islam A.; Mohamed, Osama N.; El-Henawy, Sally I.; Galal, Ola; Taha, Iman; Nassar, Khaled; Safwat, Amr M. E.

    2014-09-01

    Cities and towns around the world are becoming more condensed due to the shrinking amount of buildable areas, which significantly reduces the amount of light that occupants have access to. This lack of natural lighting results in health, safety and quality of life degradation. This paper presents a new technique of transmitting sunlight downward into narrow alleys and streets, by using a daylighting guiding acrylic panel that is capable of changing the direction and distribution of the incident light. The core of the proposed daylight guidance system is made up of light transmission panels with high quality. The corrugations have sine wave shaped cross-section so that the panel functions as an optical diffuser perpendicular to the direction of sunlight propagation. The day lighting system consists of the corrugated panels and a lattice frame, which supports the panel. The proposed system is to be mounted on the building roof facing the sun so as to redirect the incident sunlight downward into the narrow alleys or streets. Since building sizes and orientations are different the frame is arranged such that substantially deep light penetration and high luminance level can be achieved. Simulation results show that the proposed panel improves the illuminance values by more than 200% and 400% in autumn and winter, respectively, provides fan-out angle that exceeds 80° for certain solar altitudes and the transmitted power percentage varies from 40% to 90% as the solar altitude varies from 10° to 80°. Experimental results are in a good agreement with the simulations.

  3. PULSE: Integrated Parametric Modeling for a Shading System : From Daylight Optimization to Additive Manufacturing

    NARCIS (Netherlands)

    Teeling, M.V.M.T.; Turrin, M.; de Ruiter, P.; Turrin, Michela; Peters, Brady; O'Brien, William; Stouffs, Rudi; Dogan, Timur

    2017-01-01

    This paper presents a parametric approach to an integrated and performance-oriented design, from the conceptual design phase towards materialization. The novelty occurs in the use of parametric models as a way of integrating multidisciplinary design constraints, from daylight optimization to the

  4. Change in the Classroom Deportment of Children Following Change From Daylight Saving Time.

    Science.gov (United States)

    Hicks, Robert A.; And Others

    1980-01-01

    The deportment of each student in a third-grade classroom was rated by the teacher before and after the fall change from daylight savings time, to see if this disruption in circadian rhythms alters behavior. The deportment of boys improved significantly while the deportment of girls was significantly disrupted. (Author/SJL)

  5. Enhanced Photocatalytic Degradation of Methyl Orange Dye under the Daylight Irradiation over CN-TiO₂ Modified with OMS-2.

    Science.gov (United States)

    Hassan, Mohamed Elfatih; Chen, Jing; Liu, Guanglong; Zhu, Duanwei; Cai, Jianbo

    2014-12-12

    In this study, CN-TiO₂ was modified with cryptomelane octahedral molecular sieves (OMS-2) by the sol-gel method based on the self-assembly technique to enhance its photocatalytic activity under the daylight irradiation. The synthesized samples were characterized by X-ray diffraction (XRD), UV-vis spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and porosimeter analysis. The results showed that the addition of OMS-2 in the sol lead to higher Brunauer-Emmett-Teller (BET) surface area, pore volume, porosity of particle after heat treatment and the specific surface area, porosity, crystallite size and pore size distribution could be controlled by adjusting the calcination temperature. Compared to the CN-TiO₂-400 sample, CN-TiO₂/OMS-2-400 exhibited greater red shift in absorption edge of samples in visible region due to the OMS-2 coated. The enhancement of photocatalytic activity of CN-TiO₂/OMS-2 composite photocatalyst was subsequently evaluated for the degradation of the methyl orange dye under the daylight irradiation in water. The results showed that the methyl orange dye degradation rate reach to 37.8% for the CN-TiO₂/OMS-2-400 sample under the daylight irradiation for 5 h, which was higher than that of reference sample. The enhancement in daylight photocatalytic activities of the CN-TiO₂/OMS samples could be attributed to the synergistic effects of OMS-2 coated, larger surface area and red shift in adsorption edge of the prepared sample.

  6. Procedure to Measure Indoor Lighting Energy Performance

    Energy Technology Data Exchange (ETDEWEB)

    Deru, M.; Blair, N.; Torcellini, P.

    2005-10-01

    This document provides standard definitions of performance metrics and methods to determine them for the energy performance of building interior lighting systems. It can be used for existing buildings and for proposed buildings. The primary users for whom these documents are intended are building energy analysts and technicians who design, install, and operate data acquisition systems, and who analyze and report building energy performance data. Typical results from the use of this procedure are the monthly and annual energy used for lighting, energy savings from occupancy or daylighting controls, and the percent of the total building energy use that is used by the lighting system. The document is not specifically intended for retrofit applications. However, it does complement Measurement and Verification protocols that do not provide detailed performance metrics or measurement procedures.

  7. The influence of the lateral distances between buildings on the availability of indoor daylighting

    Directory of Open Access Journals (Sweden)

    Andrea Coelho Laranja

    2014-12-01

    Full Text Available This study addresses aspects related to daylighting in the indoor environment, more specifically the influence of lateral distances between obstructing buildings on the availability of indoor daylighting, taking the height of the buildings and width of the roads into account. In accordance with the adopted methodology, comparisons were made of the percentage of illuminance values of the internal environment by using UDI (Useful Daylight Illuminance ranges on a selected point within an interior environment with an opening oriented to the North. The percentages of illuminance values were generated by simulation using the TropLux program in a rectangular geometry environment inserted in an urban setting in the city of Vitória, Espírito Santo (Latitude 20°19'S. The simulations were carried out for three types of sky patterns recognized by the CIE (Commission Internationale L'aclairage. One of the main results of this study was that, in locations with sky types 3 (overcast, 7 (partly cloudy, and 12 (clear, there were greater variations in the average annual internal illuminance when there were changes in the lateral distances between the obstructing buildings that were not directly in front of the building that was being analyzed. It was also found that in area with sky types 3 (overcast, 7 (partly cloudy, and 12 (clear, changes in the lateral distances between the three obstructing buildings had little effect on percentage changes in the 100≤UDI≤500 lux range and 500≤UDI ≤2000 lux range.

  8. Strong white light emission from a processed porous silicon and its photoluminescence mechanism

    International Nuclear Information System (INIS)

    Karacali, T.; Cicek, K.

    2011-01-01

    We have prepared various porous silicon (PS) structures with different surface conditions (any combination of oxidation, carbonization as well as thermal annealing) to increase the intensity of photoluminescence (PL) spectrum in the visible range. Strong white light (similar to day-light) emission was achieved by carrying out thermal annealing at 1100 deg. C after surface modification with 1-decene of anodic oxidized PS structures. Temperature-dependent PL measurements were first performed by gradually increasing the sample temperature from 10 to 300 K inside a cryostat. Then, we analyzed the measured spectrum of all prepared samples. After the analysis, we note that throughout entire measured spectrum, only two main peaks corresponding to blue and green-orange emission lines (which can be interpreted by quantum size effect and/or configuration coordinate model) were seem to be predominant for all temperature range. To further reveal and analysis these peaks, finally, measured data were inputted into the formula of activation energy of thermal excitation. We found that activation energies of blue and green-orange lines were approximately 49.3 and 44.6 meV, respectively. - Highlights: →Light emitting devices based on silicon technology are of great interest in illumination and display applications. → We have achieved strong white light (similar to day-light) emission from porous silicon. → The most important impact of carbonization on porous silicon and post annealing is the enhancement of room temperature luminescence.

  9. Neither artificial light at night, anthropogenic noise nor distance from roads are associated with oxidative status of nestlings in an urban population of songbirds.

    Science.gov (United States)

    Casasole, Giulia; Raap, Thomas; Costantini, David; AbdElgawad, Hamada; Asard, Han; Pinxten, Rianne; Eens, Marcel

    2017-08-01

    Increasing urbanization is responsible for road-related pollutants and causes an unprecedented increase in light and noise pollution, with potential detrimental effects for individual animals, communities and ecosystems. These stressors rarely act in isolation but studies dissecting the effects of these multiple stressors are lacking. Moreover, studies on urban stressors have mainly focused on adults, while exposure in early-life may be detrimental but is largely ignored. To fill this important knowledge gap, we studied if artificial light at night, anthropogenic noise and road-related pollution (using distance from roads as a proxy) explain variation in oxidative status in great tit nestlings (Parus major) in an urban population. Artificial light at night, anthropogenic noise and distance from roads were not associated with variation of the nine studied metrics of oxidative status (superoxide dismutase-SOD-, glutathione peroxidase-GPX, catalase-CAT-, non-enzymatic total antioxidant capacity-TAC-, reduced glutathione-GSH-, oxidized glutathione-GSSG-, ratio GSH/GSSG, protein carbonyls and thiobarbituric acid reactive substances-TBARS). Interestingly, for all oxidative status metrics, we found that there was more variation in oxidative status among individuals of the same nest compared to between different nests. We also showed an increase in protein carbonyls and a decrease of the ratio GSH/GSSG as the day advanced, and an increase of GPX when weather conditions deteriorated. Our study suggests that anthropogenic noise, artificial light at night and road-related pollution are not the most important sources of variation in oxidative status in great tit nestlings. It also highlights the importance of considering bleeding time and weather conditions in studies with free-living animals. Copyright © 2017. Published by Elsevier Inc.

  10. Resource use efficiency of closed plant production system with artificial light: concept, estimation and application to plant factory.

    Science.gov (United States)

    Kozai, Toyoki

    2013-01-01

    Extensive research has recently been conducted on plant factory with artificial light, which is one type of closed plant production system (CPPS) consisting of a thermally insulated and airtight structure, a multi-tier system with lighting devices, air conditioners and fans, a CO2 supply unit, a nutrient solution supply unit, and an environment control unit. One of the research outcomes is the concept of resource use efficiency (RUE) of CPPS.This paper reviews the characteristics of the CPPS compared with those of the greenhouse, mainly from the viewpoint of RUE, which is defined as the ratio of the amount of the resource fixed or held in plants to the amount of the resource supplied to the CPPS.It is shown that the use efficiencies of water, CO2 and light energy are considerably higher in the CPPS than those in the greenhouse. On the other hand, there is much more room for improving the light and electric energy use efficiencies of CPPS. Challenging issues for CPPS and RUE are also discussed.

  11. Examination of Color-Lighting Control System Using Colored Paper User Interface

    Directory of Open Access Journals (Sweden)

    Aida Hiroto

    2016-01-01

    Full Text Available In recent year, Full-Color LED Lighting that can be changed to various color such as red, green, blue has been appeared with development of LED Lighting. By Color-Lighting control, users affected such as concentrating and relaxing. Therefore, Color-lighting control will spread to various place such as home, offices, stations. However color-lighting control affected some disturbance such as daylight, display when Full-Color LED controlled indoors. Also, information devices control get difficult with information technology develop. I propose Color-Lighting Control System using Colored Paper User Interface(CLC/CPUI. The purpose of CLC/CPUI is that anyone can intuitively control Full-Color LED Lighting. CLC/CPUI uses colored paper as user interface by sensing the paper. CLC/CPUI realizes lighting color that user demanded to do feedback control. I conduct accuracy verification experiment of CLC/CPUI.

  12. Simulation of annual electric lighting demand using various occupancy profiles

    DEFF Research Database (Denmark)

    Iversen, Anne; Andersen, Philip Hvidthøft Delff; Svendsen, Svend

    2013-01-01

    This paper describes an investigation of the effect on electric lighting demand of applying occupancy models of various resolution to climate-based daylight modelling. The lighting demand was evaluated for a building zone with the occupant always present, with occupancy corresponding to absence...... factors, based on an estimated annual mean occupancy, based on estimated 1-hour mean occupancy, and based on 2-min occupancy intervals. The results showed little difference in the annual electric lighting demand when the same occupancy profile was used every day, as opposed to when profiles were used...... where occupancy varied every day. Furthermore, the results showed that annual electric lighting demand was evaluated slightly conservatively when a mean absence factor was applied as opposed to using dynamic occupancy profiles....

  13. Problems of natural lighting for deepened buildings and underground premises under screen effect of high-rise construction

    Directory of Open Access Journals (Sweden)

    Larionova Kira

    2018-01-01

    Full Text Available The main rationale and objective of the submitted research work is to create a quality lighting environment in the premises of deepened buildings and below-ground structures under screen effect of high-rise construction (high-rise buildings. It is noted, that in modern megapolises, a deficiency of vacant urban territories leads to the increased density of urban development with increased amount of high-rise construction and tendency to increase efficiency in the use of underground space. The natural lighting of premises in underground buildings and structures is the most efficient way, but it can be implemented only under use of roof lighting system in the form of roof monitors or skylights. In this case the levels of indoor natural lighting will be affected with serious screening effect of high-rise buildings in surrounding development. Such an situation is not regulated, or even considered by the contemporary building Codes and Regulations on natural lighting of interiors. The authors offered a new formula for a daylight factor calculation with roof lighting system in the described cases. The results of theoretical calculations and experimental studies showed very similar values. This proved the truth of the offered formula and elaborated method of calculation on the basis of an offered hypothesis. It prooves, that it is possible to use some factor and guide points in the daylight factors design under system of side natural lighting in the same design for a system of roof lighting.

  14. Problems of natural lighting for deepened buildings and underground premises under screen effect of high-rise construction

    Science.gov (United States)

    Larionova, Kira; Stetsky, Sergey

    2018-03-01

    The main rationale and objective of the submitted research work is to create a quality lighting environment in the premises of deepened buildings and below-ground structures under screen effect of high-rise construction (high-rise buildings). It is noted, that in modern megapolises, a deficiency of vacant urban territories leads to the increased density of urban development with increased amount of high-rise construction and tendency to increase efficiency in the use of underground space. The natural lighting of premises in underground buildings and structures is the most efficient way, but it can be implemented only under use of roof lighting system in the form of roof monitors or skylights. In this case the levels of indoor natural lighting will be affected with serious screening effect of high-rise buildings in surrounding development. Such an situation is not regulated, or even considered by the contemporary building Codes and Regulations on natural lighting of interiors. The authors offered a new formula for a daylight factor calculation with roof lighting system in the described cases. The results of theoretical calculations and experimental studies showed very similar values. This proved the truth of the offered formula and elaborated method of calculation on the basis of an offered hypothesis. It prooves, that it is possible to use some factor and guide points in the daylight factors design under system of side natural lighting in the same design for a system of roof lighting.

  15. Nutrition in the spotlight: metabolic effects of environmental light

    NARCIS (Netherlands)

    Versteeg, Ruth I.; Stenvers, Dirk J.; Kalsbeek, Andries; Bisschop, Peter H.; Serlie, Mireille J.; la Fleur, Susanne E.

    2016-01-01

    Use of artificial light resulted in relative independence from the natural light-dark (LD) cycle, allowing human subjects to shift the timing of food intake and work to convenient times. However, the increase in artificial light exposure parallels the increase in obesity prevalence. Light is the

  16. Nutrition in the spotlight metabolic effects of environmental light

    NARCIS (Netherlands)

    Versteeg, Ruth I; Stenvers, Dirk J; Kalsbeek, A.; Bisschop, Peter H; Serlie, Mireille J; la Fleur, Susanne E

    2016-01-01

    Use of artificial light resulted in relative independence from the natural light-dark (LD) cycle, allowing human subjects to shift the timing of food intake and work to convenient times. However, the increase in artificial light exposure parallels the increase in obesity prevalence. Light is the

  17. Establishment and verification of solar radiation calculation model of glass daylighting roof in hot summer and warm winter zone in China

    OpenAIRE

    Zheng, Caidan; Wu, Peihao; Costanzo, Vincenzo; Wang, Yuchen; Yang, Xiaokun

    2017-01-01

    In this paper, solar heat gain through glass daylighting roof is deeply studied by theoretical calculation method, taking Guangzhou in the Hot Summer and Warm Winter (HSWW) zone as an example. The direct solar radiation is calculated by Bouguer formula whereas the diffuse solar radiation is calculated by Berlage formula, representing the basis for the calculation method of the solar radiation intensity through the glass daylighting roof. Through the establishment of solar radiation calculatio...

  18. Robustness of circadian clocks to daylight fluctuations: hints from the picoeucaryote Ostreococcus tauri.

    Directory of Open Access Journals (Sweden)

    Quentin Thommen

    Full Text Available The development of systemic approaches in biology has put emphasis on identifying genetic modules whose behavior can be modeled accurately so as to gain insight into their structure and function. However, most gene circuits in a cell are under control of external signals and thus, quantitative agreement between experimental data and a mathematical model is difficult. Circadian biology has been one notable exception: quantitative models of the internal clock that orchestrates biological processes over the 24-hour diurnal cycle have been constructed for a few organisms, from cyanobacteria to plants and mammals. In most cases, a complex architecture with interlocked feedback loops has been evidenced. Here we present the first modeling results for the circadian clock of the green unicellular alga Ostreococcus tauri. Two plant-like clock genes have been shown to play a central role in the Ostreococcus clock. We find that their expression time profiles can be accurately reproduced by a minimal model of a two-gene transcriptional feedback loop. Remarkably, best adjustment of data recorded under light/dark alternation is obtained when assuming that the oscillator is not coupled to the diurnal cycle. This suggests that coupling to light is confined to specific time intervals and has no dynamical effect when the oscillator is entrained by the diurnal cycle. This intriguing property may reflect a strategy to minimize the impact of fluctuations in daylight intensity on the core circadian oscillator, a type of perturbation that has been rarely considered when assessing the robustness of circadian clocks.

  19. Intelligent Lighting Control System

    OpenAIRE

    García, Elena; Rodríguez González, Sara; de Paz Santana, Juan F.; Bajo Pérez, Javier

    2014-01-01

    This paper presents an adaptive architecture that allows centralized control of public lighting and intelligent management, in order to economise on lighting and maintain maximum comfort status of the illuminated areas. To carry out this management, architecture merges various techniques of artificial intelligence (AI) and statistics such as artificial neural networks (ANN), multi-agent systems (MAS), EM algorithm, methods based on ANOVA and a Service Oriented Aproach (SOA). It performs optim...

  20. A phytotron for plant stress research: how far can artificial lighting compare to natural sunlight?

    International Nuclear Information System (INIS)

    Thiel, S.; Döhring, T.; Köfferlein, M.; Kosak, A.; Martin, P.; Seidlitz, H.K.

    1996-01-01

    Plants have adapted very efficiently to their natural light habitat. Artificial plant illumination, therefore, requires careful design. Not only the quantity of radiation per area or volume (intensity) but also the spectral quality has to match seasonal and diurnal variations of natural global radiation as close as possible. The GSF Research Center has developed a phytotron system especially devoted to plant stress research, where these requirements are of particular importance. The phytotron consists of seven closed chambers (4 walk-in size chambers, two medium and one small sun simulator). Our contribution outlines the basic design of the lighting and presents spectral data. A good approximation of terrestrial global radiation is achieved if several commercially available lamp types are combined and adequate filters are applied to reject unwanted infrared and harmful ultraviolet radiation. A programmable switch control for the individual lamp banks allows a variation of both spectrum and intensity of the illumination. Spectroradiometric measurements show that the maximum level of illumination in the small and in the medium size chambers can compete both in spectral distribution and in intensity with outdoor global radiation for solar elevations up to 60°. The maximum light level available inside the large walk-in chambers reaches an irradiance corresponding to solar elevation of 50°. The UV-B: UV-A: PAR ratio, which mirrors the spectral balance of plant lighting, can be adjusted to values following the diurnal variation of natural global radiation.(author)

  1. Thermal and Daylighting Performance of Energy-Efficient Windows in Highly Glazed Residential Buildings: Case Study in Korea

    Directory of Open Access Journals (Sweden)

    Chang Heon Cheong

    2014-10-01

    Full Text Available Cooling load in highly glazed residential building can be excessively large due to uncontrolled solar energy entering the indoor space. This study focuses on the cooling load reduction and changes in the daylighting properties via the application of a double window system (DWS with shading with various surface reflectivities in highly glazed residential buildings. Evaluation of thermal and daylighting performances is carried out using simulation tools. The reductions in cooling load and energy cost through the use of DWS are evaluated through a comparative simulation considering conventional windows: a single window and a double window. Three variables of window types, natural ventilation, and shading reflectivity are reflected in the study. According to our results, implementation of DWS reduced cooling load by 43%–61%. Electricity cost during the cooling period was reduced by a maximum of 24%. However, a shading device setting that prioritizes effective cooling load reduction can greatly decrease the daylighting factor and luminance level of indoor space. A DWS implementing shading device with highly reflective at all surfaces is appropriate option for the more comfortable thermal and visual environment, while a shading device with low reflectivity at rear of the surface can contribute an additional 4% cooling load reduction.

  2. Glucose Synthesis in a Protein-Based Artificial Photosynthesis System.

    Science.gov (United States)

    Lu, Hao; Yuan, Wenqiao; Zhou, Jack; Chong, Parkson Lee-Gau

    2015-09-01

    The objective of this study was to understand glucose synthesis of a protein-based artificial photosynthesis system affected by operating conditions, including the concentrations of reactants, reaction temperature, and illumination. Results from non-vesicle-based glyceraldehyde-3-phosphate (GAP) and glucose synthesis showed that the initial concentrations of ribulose-1,5-bisphosphate (RuBP) and adenosine triphosphate (ATP), lighting source, and temperature significantly affected glucose synthesis. Higher initial concentrations of RuBP and ATP significantly enhanced GAP synthesis, which was linearly correlated to glucose synthesis, confirming the proper functions of all catalyzing enzymes in the system. White fluorescent light inhibited artificial photosynthesis and reduced glucose synthesis by 79.2 % compared to in the dark. The reaction temperature of 40 °C was optimum, whereas lower or higher temperature reduced glucose synthesis. Glucose synthesis in the vesicle-based artificial photosynthesis system reconstituted with bacteriorhodopsin, F 0 F 1 ATP synthase, and polydimethylsiloxane-methyloxazoline-polydimethylsiloxane triblock copolymer was successfully demonstrated. This system efficiently utilized light-induced ATP to drive glucose synthesis, and 5.2 μg ml(-1) glucose was synthesized in 0.78-ml reaction buffer in 7 h. Light-dependent reactions were found to be the bottleneck of the studied artificial photosynthesis system.

  3. External perforated Solar Screens for daylighting in residential desert buildings: Identification of minimum perforation percentages

    KAUST Repository

    Sherif, Ahmed; Sabry, Hanan; Rakha, Tarek

    2012-01-01

    and Saudi Arabia, result in the admittance of direct solar radiation, which leads to thermal discomfort and the incidence of undesired glare. One type of shading systems that is used to permit daylight while controlling solar penetration is " Solar Screens

  4. Artificial Light at Night Reduces Daily Energy Expenditure in Breeding Great Tits (Parus major

    Directory of Open Access Journals (Sweden)

    Anouk A. M. H. Welbers

    2017-05-01

    Full Text Available The ecological impact of artificial light at night (ALAN is an increasingly recognized process that accompanies expanding urbanization. Yet, we have limited knowledge on the impact of ALAN on wild species, and on the potential to mitigate any negative effects by using different light sources and colors. In birds, effects of ALAN on activity levels are reported for several species and, hence, their daily energy expenditure (DEE may be affected. DEE is a potent mediator of life-history trade-offs and fitness and thus an important aspect to consider when examining the potential long-term ecological effects of ALAN. Previous work has suggested that birds exposed to ALAN show higher levels of provisioning and nocturnal activity, suggesting that white ALAN increases DEE. Other factors regulating DEE, such as provisioning behavior and food availability, might also respond to ALAN and thus indirectly affect DEE. We tested the hypothesis that ALAN increases DEE using an experimental setup where four previously unlit transects were illuminated with either white, green, or red LED light, or left dark as a control treatment. This setup was replicated in eight locations across the Netherlands. We measured DEE of our focal species, the great tit (Parus major, using a novel doubly labeled water technique that uses breath rather than blood samples. Contrary to our expectations, birds feeding their offspring under white and green ALAN showed lower DEE compared to birds in the control dark treatment. Differences in chick provisioning activity did not explain this result, as neither visit rates nor daily activity timing was affected by light treatment. However, food availability under white and green light was much higher compared to red light and the dark control. This difference strongly suggests that the lower DEE under white and green ALAN sites is a consequence of higher food availability in these treatments. This result shows that there can be positive

  5. A New Look for the Shopping Mall

    Science.gov (United States)

    1985-01-01

    STRUCTO-FAB, a product of Owens-Corning Fiberglas Corporation, is a lightweight but extremely durable tent-like material made of Fiberglas coated with Teflon. It transmits daylight with a reduced need for artificial lighting. It is an outgrowth of a material formulated by NASA in 1967 as a new space suit fabric. Owens-Corning and DuPont provided the original material, which was the basis for Structo-Fab, a permanent architectural fabric used for shopping malls, sports stadiums, etc.

  6. Exposure to dim artificial light at night increases REM sleep and awakenings in humans.

    Science.gov (United States)

    Cho, Chul-Hyun; Lee, Heon-Jeong; Yoon, Ho-Kyoung; Kang, Seung-Gul; Bok, Ki-Nam; Jung, Ki-Young; Kim, Leen; Lee, Eun-Il

    2016-01-01

    Exposure to artificial light at night (ALAN) has become increasing common, especially in developed countries. We investigated the effect of dALAN exposure during sleep in healthy young male subjects. A total of 30 healthy young male volunteers from 21 to 29 years old were recruited for the study. They were randomly divided into two groups depending on light intensity (Group A: 5 lux and Group B: 10 lux). After a quality control process, 23 healthy subjects were included in the study (Group A: 11 subjects, Group B: 12 subjects). Subjects underwent an NPSG session with no light (Night 1) followed by an NPSG session randomly assigned to two different dim light conditions (5 or 10 lux, dom λ: 501.4 nm) for a whole night (Night 2). We found significant sleep structural differences between Nights 1 and 2, but no difference between Groups A and B. Exposure to dALAN during sleep was significantly associated with increased wake time after sleep onset (WASO; F = 7.273, p = 0.014), increased Stage N1 (F = 4.524, p = 0.045), decreased Stage N2 (F = 9.49, p = 0.006), increased Stage R (F = 6.698, p = 0.017) and non-significantly decreased REM density (F = 4.102, p = 0.056). We found that dALAN during sleep affects sleep structure. Exposure to dALAN during sleep increases the frequency of arousals, amount of shallow sleep and amount of REM sleep. This suggests adverse effects of dALAN during sleep on sleep quality and suggests the need to avoid exposure to dALAN during sleep.

  7. An artificial light-harvesting array constructed from multiple Bodipy dyes.

    Science.gov (United States)

    Ziessel, Raymond; Ulrich, Gilles; Haefele, Alexandre; Harriman, Anthony

    2013-07-31

    An artificial light-harvesting array, comprising 21 discrete chromophores arranged in a rational manner, has been synthesized and characterized fully. The design strategy follows a convergent approach that leads to a molecular-scale funnel, having an effective chromophore concentration of 0.6 M condensed into ca. 55 nm(3), able to direct the excitation energy to a focal point. A cascade of electronic energy-transfer steps occurs from the rim to the focal point, with the rate slowing down as the exciton moves toward its ultimate target. Situated midway along each branch of the V-shaped array, two chromophoric relays differ only slightly in terms of their excitation energies, and this situation facilitates reverse energy transfer. Thus, the excitation energy becomes spread around the array, a situation reminiscent of a giant holding pattern for the photon that can sample many different chromophores before being trapped by the terminal acceptor. At high photon flux under conditions of relatively slow off-load to a device, such as a solar cell, electronic energy transfer encounters one or more barriers that hinder forward progress of the exciton and thereby delays arrival of the second photon. Preliminary studies have addressed the ability of the array to function as a sensitizer for amorphous silicon solar cells.

  8. Effect of short-term simulated daylight exposure on optically brightened papers

    International Nuclear Information System (INIS)

    Green, Phil; Honess, Mike

    2010-01-01

    Two optically brightened commercial papers were subjected to 72 hours continuous exposure to graphic arts daylight simulating fluorescent lamps at 1.4 and 4.4 klux. At the higher illuminance level, a CIELAB colour difference of 1.0 was reached in approximately 3 and 50 hours for the two papers. The colour differences produced by the 1.4 klux exposure were greater than that predicted by assuming a linear relationship between intensity and colour change, by a factor of 1.8.

  9. Illuminating the Effects of Dynamic Lighting on Student Learning

    Directory of Open Access Journals (Sweden)

    Michael S. Mott

    2012-05-01

    Full Text Available Light is universally understood as essential to the human condition. Yet light quality varies substantially in nature and in controlled environments leading to questions of which artificial light characteristics facilitate maximum learning. Recent research has examined lighting variables of color temperature, and illumination for affecting sleep, mood, focus, motivation, concentration, and work and school performance. This has resulted in artificial light systems intended to support human beings in their actualization through dynamic lighting technology allowing for different lighting conditions per task. A total of 84 third graders were exposed to either focus (6000K-100fc average maintained or normal lighting. Focus lighting led to a higher percentage increase in oral reading fluency performance (36% than did control lighting (17%. No lighting effects were found for motivation or concentration, possibly attributable to the younger age level of respondents as compared with European studies. These findings illuminate the need for further research on artificial light and learning.

  10. Adaptive lighting controllers using smart sensors

    Science.gov (United States)

    Papantoniou, Sotiris; Kolokotsa, Denia; Kalaitzakis, Kostas; Cesarini, Davide Nardi; Cubi, Eduard; Cristalli, Cristina

    2016-07-01

    The aim of this paper is to present an advanced controller for artificial lights evaluated in several rooms in two European Hospitals located in Chania, Greece and Ancona, Italy. Fuzzy techniques have been used for the architecture of the controller. The energy efficiency of the controllers has been calculated by running the controller coupled with validated models of the RADIANCE back-wards ray tracing software. The input of the controller is the difference between the current illuminance value and the desired one, while the output is the change of the light level that should be applied in the artificial lights. Simulation results indicate significant energy saving potentials. Energy saving potential is calculated from the comparison of the current use of the artificial lights by the users and the proposed one. All simulation work has been conducted using Matlab and RADIANCE environment.

  11. Alteration of blue pigment in artificial iris in ocular prosthesis: effect of paint, drying method and artificial aging.

    Science.gov (United States)

    Goiato, Marcelo Coelho; Fernandes, Aline Úrsula Rocha; dos Santos, Daniela Micheline; Hadadd, Marcela Filié; Moreno, Amália; Pesqueira, Aldiéris Alves

    2011-02-01

    The artificial iris is the structure responsible for the dissimulation and aesthetics of ocular prosthesis. The objective of the present study was to evaluate the color stability of artificial iris of microwaveable polymerized ocular prosthesis, as a function of paint type, drying method and accelerated aging. A total of 40 discs of microwaveable polymerized acrylic resin were fabricated, and divided according to the blue paint type (n = 5): hydrosoluble acrylic, nitrocellulose automotive, hydrosoluble gouache and oil paints. Paints where dried either at natural or at infrared light bulb method. Each specimen was constituted of one disc in colorless acrylic resin and another colored with a basic sclera pigment. Painting was performed in one surface of one of the discs. The specimens were submitted to an artificial aging chamber under ultraviolet light, during 1008 h. A reflective spectrophotometer was used to evaluate color changes. Data were evaluated by 3-way repeated-measures ANOVA and the Tukey HSD test (α = 0.05). All paints suffered color alteration. The oil paint presented the highest color resistance to artificial aging regardless of drying method. Copyright © 2010 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  12. Atmosphere self-cleaning under humidity conditions and influence of the snowflakes and artificial light interaction for water dissociation simulated by the means of COMSOL

    Science.gov (United States)

    Cocean, A.; Cocean, I.; Cazacu, M. M.; Bulai, G.; Iacomi, F.; Gurlui, S.

    2018-06-01

    The self-cleaning of the atmosphere under humidity conditions is observed due to the change in emission intensity when chemical traces are investigated with DARLIOES - the advanced LIDAR based on space- and time-resolved RAMAN and breakdown spectroscopy in conditions of consistent humidity of atmosphere. The determination was performed during the night, in the wintertime under conditions of high humidity and snowfall, in urban area of Iasi. The change in chemical composition of the atmosphere detected was assumed to different chemical reactions involving presence of the water. Water dissociation that was registered during spectral measurements is explained by a simulation of the interaction between artificial light and snowflakes - virtually designed in a spherical geometry - in a wet air environment, using COMSOL Multiphysics software. The aim of the study is to explain the decrease or elimination of some of the toxic trace chemical compounds in the process of self-cleaning in other conditions than the sun light interaction for further finding application for air cleaning under artificial conditions.

  13. Practical approach to the use of daylight photodynamic therapy with topical methyl aminolevulinate for actinic keratosis

    DEFF Research Database (Denmark)

    Morton, C A; Wulf, H C; Szeimies, R M

    2015-01-01

    INTRODUCTION: Daylight-mediated photodynamic therapy has been shown to be an effective therapy for actinic keratoses (AKs) and a simple and tolerable treatment procedure in three randomized Scandinavian studies and two recent Phase III randomized controlled studies in Australia and Europe...

  14. NATURAL IRON OXIDE AS A HETEROGENEOUS PHOTO-FENTON-LIKE CATALYST FOR THE DEGRADATION OF 1-NAPHTHOL UNDER ARTIFICIAL AND SOLAR LIGHT

    Directory of Open Access Journals (Sweden)

    L MAMMERI

    2014-07-01

    Full Text Available A heterogeneous photo-Fenton-like degradation process of 1-naphthol (1-NP promoted by natural iron oxide (NIO in the presence of H2O2 was studied under artificial (365 nm and solar irradiation. This is an important reaction for the environment since both H2O2 and iron oxides are common constituents of natural waters. Furthermore, iron oxides function as catalysts in chemical oxidation processes used with H2O2 for treatment of contaminated waters. The NIO used in this study was characterized by X-ray diffraction (XRD, X-ray fluorescence and Brunauer–Emmett–Teller (BET methods. The results show that the NIO is a composite material that contains predominantly crystalline hematite particales (Fe2O3. The Fe2O3 in NIO was able to initiate the Fenton-like and photo-Fenton-like reactions. The effects of initial pH, catalyst dosage, H2O2 concentration and the wavelength of the light source (UV and solar on the photodegradation of 1-NP were investigated. The optimal content of the NIO was 1 g L-1 and the optimal H2O2 concentration was 10 mM. The degradation could occur efficiently over a wide pH range of 3-8.3. Furthermore, an important effect of light was observed. The photo-oxidation of 1-NP in NIO-H2O2 system under solar light was significantly accelerated in comparison with artificial irradiation at 365 nm.

  15. A generalized window energy rating system for typical office buildings

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Cheng; Chen, Tingyao; Yang, Hongxing; Chung, Tse-ming [Research Center for Building Environmental Engineering, Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong (China)

    2010-07-15

    Detailed computer simulation programs require lengthy inputs, and cannot directly provide an insight to relationship between the window energy performance and the key window design parameters. Hence, several window energy rating systems (WERS) for residential houses and small buildings have been developed in different countries. Many studies showed that utilization of daylight through elaborate design and operation of windows leads to significant energy savings in both cooling and lighting in office buildings. However, the current WERSs do not consider daylighting effect, while most of daylighting analyses do not take into account the influence of convective and infiltration heat gains. Therefore, a generalized WERS for typical office buildings has been presented, which takes all primary influence factors into account. The model includes embodied and operation energy uses and savings by a window to fully reflect interactions among the influence parameters. Reference locations selected for artificial lighting and glare control in the current common simulation practice may cause uncompromised conflicts, which could result in over- or under-estimated energy performance. Widely used computer programs, DOE2 and ADELINE, for hourly daylighting and cooling simulations have their own weaknesses, which may result in unrealistic or inaccurate results. An approach is also presented for taking the advantages of the both programs and avoiding their weaknesses. The model and approach have been applied to a typical office building of Hong Kong as an example to demonstrate how a WERS in a particular location can be established and how well the model can work. The energy effect of window properties, window-to-wall ratio (WWR), building orientation and lighting control strategies have been analyzed, and can be indicated by the localized WERS. An application example also demonstrates that the algebraic WERS derived from simulation results can be easily used for the optimal design of

  16. Natural and artificial spectral edges in exoplanets

    Science.gov (United States)

    Lingam, Manasvi; Loeb, Abraham

    2017-09-01

    Technological civilizations may rely upon large-scale photovoltaic arrays to harness energy from their host star. Photovoltaic materials, such as silicon, possess distinctive spectral features, including an 'artificial edge' that is characteristically shifted in wavelength shortwards of the 'red edge' of vegetation. Future observations of reflected light from exoplanets would be able to detect both natural and artificial edges photometrically, if a significant fraction of the planet's surface is covered by vegetation or photovoltaic arrays, respectively. The stellar energy thus tapped can be utilized for terraforming activities by transferring heat and light from the day side to the night side on tidally locked exoplanets, thereby producing detectable artefacts.

  17. Continuous light-emitting Diode (LED) lighting for improving food quality

    OpenAIRE

    Lu, C; Bian, Z

    2016-01-01

    Lighting-emitting diodes (LEDs) have shown great potential for plant growth and development, with higher luminous efficiency and positive impact compared with other artificial lighting. The combined effects of red/blue or/and green, and white LED light on plant growth and physiology, including chlorophyll fluorescence, nitrate content and phytochemical concentration before harvest, were investigated. The results showed that continuous light (CL)\\ud exposure at pre-harvest can effectively redu...

  18. Photoluminescence properties of white light emitting La2O3:Dy3+ nanocrystals

    Science.gov (United States)

    Reenabati Devi, Konsam; Dorendrajit Singh, Shougaijam; David Singh, Th.

    2018-01-01

    White light emitting nanocrystalline La2O3:Dy3+ phosphors with different concentration (0.5-2 at.%) were synthesized by simple precipitation method. X-ray diffraction (XRD) pattern indicates all the samples crystallizes in the hexagonal phase. Average crystallite sizes of the samples calculated from XRD data were found to be in the range of 20-55 nm. Transmission electron microscopy, selected area electron diffraction, energy dispersive analysis of X-ray and photoluminescence (PL) of the samples are also reported. Strong PL excitation peak due to charge transfer band was observed at 230 nm. Photoluminescence emission peaks observed at 486 and 575 nm were probably attributed to 4F9/2-6H15/2 and 4F9/2-6H13/2 of Dy3+ ions respectively. Optimum luminescence intensity is found at 1 at.% Dy3+ doped La2O3 sample. Further, Commission Internationale de l'é clairage (CIE, 1931) co-ordinates and correlated color temperature (CCT) of the doped sample were calculated to investigate the phosphors' performance and technical applicability of the emitted light respectively. CCT of the 0.5 and 1 at.% samples is 5894 K (white light), within the range of vertical daylight, which makes the synthesised samples promising nanophosphor and may find application in simulating vertical daylight of the Sun.

  19. An Adaptive Intelligent Integrated Lighting Control Approach for High-Performance Office Buildings

    Science.gov (United States)

    Karizi, Nasim

    An acute and crucial societal problem is the energy consumed in existing commercial buildings. There are 1.5 million commercial buildings in the U.S. with only about 3% being built each year. Hence, existing buildings need to be properly operated and maintained for several decades. Application of integrated centralized control systems in buildings could lead to more than 50% energy savings. This research work demonstrates an innovative adaptive integrated lighting control approach which could achieve significant energy savings and increase indoor comfort in high performance office buildings. In the first phase of the study, a predictive algorithm was developed and validated through experiments in an actual test room. The objective was to regulate daylight on a specified work plane by controlling the blind slat angles. Furthermore, a sensor-based integrated adaptive lighting controller was designed in Simulink which included an innovative sensor optimization approach based on genetic algorithm to minimize the number of sensors and efficiently place them in the office. The controller was designed based on simple integral controllers. The objective of developed control algorithm was to improve the illuminance situation in the office through controlling the daylight and electrical lighting. To evaluate the performance of the system, the controller was applied on experimental office model in Lee et al.'s research study in 1998. The result of the developed control approach indicate a significantly improvement in lighting situation and 1-23% and 50-78% monthly electrical energy savings in the office model, compared to two static strategies when the blinds were left open and closed during the whole year respectively.

  20. Critical analysis of the daylight saving time; Analisis critico al horario del verano

    Energy Technology Data Exchange (ETDEWEB)

    Romero Paredes Rubio, Hernando [Universidad Autonoma Metropolitana Ciudad-Ixtapalapa, Mexico, D.F., (Mexico)

    2001-07-01

    The critical analysis is presented as a synthesis of the problem untied since the implementation of the daylight saving time. The often related history is retaken to introduce the reader into the context of the causes of a such program. The geometric aspect of the solar trajectories is discussed and the length of the day as a function of the latitude and the time of the year to have technical elements for the time displacement in a certain region. The technical implementation of the daylight saving time based on three elements is justified: time of dawn and the decline (length of the day), national economic motivation and tourism industry. Stands out that although the daylight saving time schedule has a set of social and economic benefits it is not centered in the individual but in the society as a whole. The errors in handling the information and the misinformation are pointed out as the main causes of the controversy, the discord and the political manipulation of competing groups. [Spanish] El analisis critico se presenta como una sintesis del problema desatado desde la implementacion del horario de verano. La historia muchas veces contada se retoma para introducir al lector en el contexto de las causas de un tal programa. Se discute el aspecto geometrico de las trayectorias solares y la longitud del dia como una funcion de la latitud y de la epoca del ano para tener elementos tecnicos para el desplazamiento horario en una region determinada. Se justifica la implementacion tecnica del horario de verano en funcion de tres elementos: hora de alba y del ocaso (longitud del dia), motivacion economica nacional e industria turistica. Se destaca que si bien el horario de verano tiene un conjunto de beneficios sociales y economicos no se centra en el individuo sino en la sociedad en su conjunto. Se senalan los errores de manejo de la informacion y la desinformacion como los principales causantes de la polemica, el desacuerdo y la manipulacion politica de grupos

  1. The Effectiveness of Light Shelf in Tropical Urban Context

    Directory of Open Access Journals (Sweden)

    Binarti Floriberta

    2016-12-01

    Full Text Available Light shelf was developed to create uniform indoor illuminance. However, in hot climates the unshaded clerestory above the shelf transmits high solar heat gain. In dense urban context, these advantages and disadvantages might vary regarding the context and position of the fenestration. This study employed an integrated energy simulation software to investigate the effectiveness of light shelf application in a tropical urban context in terms of building energy consumption. Radiance and EnergyPlus based simulations performed the effects of urban canyon aspect ratio and external surface albedo on the daylighting performances, space cooling load, as well as the lighting energy consumption of the building equipped with lightshelves in 2 humid tropical cities. Comparison of the energy performances of 3 fenestration systems, i.e. fenestration without any shading device, with overhangs, and with light shelves, yielded some recommendations concerning the best application of light shelf on the certain floor levels and aspect ratio of the urban context.

  2. The design and optimization for light-algae bioreactor controller based on Artificial Neural Network-Model Predictive Control

    Science.gov (United States)

    Hu, Dawei; Liu, Hong; Yang, Chenliang; Hu, Enzhu

    As a subsystem of the bioregenerative life support system (BLSS), light-algae bioreactor (LABR) has properties of high reaction rate, efficiently synthesizing microalgal biomass, absorbing CO2 and releasing O2, so it is significant for BLSS to provide food and maintain gas balance. In order to manipulate the LABR properly, it has been designed as a closed-loop control system, and technology of Artificial Neural Network-Model Predictive Control (ANN-MPC) is applied to design the controller for LABR in which green microalgae, Spirulina platensis is cultivated continuously. The conclusion is drawn by computer simulation that ANN-MPC controller can intelligently learn the complicated dynamic performances of LABR, and automatically, robustly and self-adaptively regulate the light intensity illuminating on the LABR, hence make the growth of microalgae in the LABR be changed in line with the references, meanwhile provide appropriate damping to improve markedly the transient response performance of LABR.

  3. The ecological impacts of nighttime light pollution: a mechanistic appraisal.

    Science.gov (United States)

    Gaston, Kevin J; Bennie, Jonathan; Davies, Thomas W; Hopkins, John

    2013-11-01

    The ecological impacts of nighttime light pollution have been a longstanding source of concern, accentuated by realized and projected growth in electrical lighting. As human communities and lighting technologies develop, artificial light increasingly modifies natural light regimes by encroaching on dark refuges in space, in time, and across wavelengths. A wide variety of ecological implications of artificial light have been identified. However, the primary research to date is largely focused on the disruptive influence of nighttime light on higher vertebrates, and while comprehensive reviews have been compiled along taxonomic lines and within specific research domains, the subject is in need of synthesis within a common mechanistic framework. Here we propose such a framework that focuses on the cross-factoring of the ways in which artificial lighting alters natural light regimes (spatially, temporally, and spectrally), and the ways in which light influences biological systems, particularly the distinction between light as a resource and light as an information source. We review the evidence for each of the combinations of this cross-factoring. As artificial lighting alters natural patterns of light in space, time and across wavelengths, natural patterns of resource use and information flows may be disrupted, with downstream effects to the structure and function of ecosystems. This review highlights: (i) the potential influence of nighttime lighting at all levels of biological organisation (from cell to ecosystem); (ii) the significant impact that even low levels of nighttime light pollution can have; and (iii) the existence of major research gaps, particularly in terms of the impacts of light at population and ecosystem levels, identification of intensity thresholds, and the spatial extent of impacts in the vicinity of artificial lights. © 2013 The Authors. Biological Reviews © 2013 Cambridge Philosophical Society.

  4. Golden perception: Simulating perceptual habits of the past.

    Science.gov (United States)

    Carbon, Claus-Christian; Deininger, Pia

    2013-01-01

    Medieval times were neither dark nor grey; natural light illuminated colourful scenes depicted in paintings through coloured windows and via artificial beeswax candlelight. When we enter, for example, a church to inspect its historic treasures ranging from mosaics to depictions of saints, we do this under quite unfavourable conditions; particularly as we mainly depend on artificial halogen, LED or fluorescent light for illuminating the desired object. As these light spectrums are different from the natural light conditions under which the old masterpieces were previously developed and perceived, the perceptual effects may dramatically differ, leading to significantly altered affective and cognitive processing. Different qualities of processing might particularly be triggered when perceiving artworks which deal with specific material prone to strong interaction with idiosyncratic light conditions, for instance gold-leafed surfaces that literally start to glow when lit by candles. We tested the perceptual experiences of a figurative piece of art which we created in 3 (foreground) by 3 (background) versions, illuminated under three different light conditions (daylight, coloured light and beeswax candlelight). Results demonstrated very different perceptual experiences with stunning effects for the interaction of the specific painting depicted on a gold-leafed background lit by candlelight.

  5. Development of a new model to predict indoor daylighting: Integration in CODYRUN software and validation

    Energy Technology Data Exchange (ETDEWEB)

    Fakra, A.H., E-mail: fakra@univ-reunion.f [Physics and Mathematical Engineering Laboratory for Energy and Environment (PIMENT), University of La Reunion, 117 rue du General Ailleret, 97430 Le Tampon (French Overseas Dpt.), Reunion (France); Miranville, F.; Boyer, H.; Guichard, S. [Physics and Mathematical Engineering Laboratory for Energy and Environment (PIMENT), University of La Reunion, 117 rue du General Ailleret, 97430 Le Tampon (French Overseas Dpt.), Reunion (France)

    2011-07-15

    Research highlights: {yields} This study presents a new model capable to simulate indoor daylighting. {yields} The model was introduced in research software called CODYRUN. {yields} The validation of the code was realized from a lot of tests cases. -- Abstract: Many models exist in the scientific literature for determining indoor daylighting values. They are classified in three categories: numerical, simplified and empirical models. Nevertheless, each of these categories of models are not convenient for every application. Indeed, the numerical model requires high calculation time; conditions of use of the simplified models are limited, and experimental models need not only important financial resources but also a perfect control of experimental devices (e.g. scale model), as well as climatic characteristics of the location (e.g. in situ experiment). In this article, a new model based on a combination of multiple simplified models is established. The objective is to improve this category of model. The originality of our paper relies on the coupling of several simplified models of indoor daylighting calculations. The accuracy of the simulation code, introduced into CODYRUN software to simulate correctly indoor illuminance, is then verified. Besides, the software consists of a numerical building simulation code, developed in the Physics and Mathematical Engineering Laboratory for Energy and Environment (PIMENT) at the University of Reunion. Initially dedicated to the thermal, airflow and hydrous phenomena in the buildings, the software has been completed for the calculation of indoor daylighting. New models and algorithms - which rely on a semi-detailed approach - will be presented in this paper. In order to validate the accuracy of the integrated models, many test cases have been considered as analytical, inter-software comparisons and experimental comparisons. In order to prove the accuracy of the new model - which can properly simulate the illuminance - a

  6. Optimising for sun and light - the environmental performance of bio-climatic high-rise offices by Malaysian architect Kenneth Yeang

    Energy Technology Data Exchange (ETDEWEB)

    Ip, K.; Puteri Shireen Jahnkassim [University of Brighton (United Kingdom). School of the Environment

    2000-07-01

    Bioclimatic highrises represent an architectural response to the problem of regionalism in highrises and are based mainly on climate as a form determinant. They integrate sky courts, the use of vertical landscaping and vegetation, sun shading and use of natural ventilation in transitional areas such as the lift and ground floor lobbies. Sensitivity studies on bioclimatic highrises in tropical climate have shown that the use of daylight to save electric light and the optimum design of the building envelope can achieve significant energy savings by maintaining the balance between thermal and lighting requirements. In this study the overall envelope of two of Ken Yeang's highrise design, Menara Mesiniaga and Menara UMNO, are optimised with regards to the balance between the opposing impacts - daylight and solar gain. Apart from the external design features, the applications of photovoltaic systems to enhance the energy efficiency of these buildings are also investigated. The optimisation is carried out through the use of the FACET computer program that incorporates the use of dynamic thermal simulation program APACHE and lighting simulation RADIANCE. The paper concludes with the energy saving potential of bioclimatic design and limitations of the current study. (author)

  7. Photoageing of Baltic amber-influence of daylight radiation behind window glass on surface colour and chemistry

    DEFF Research Database (Denmark)

    Shashoua, Yvonne

    2011-01-01

    The aim of this study was to provide evidence about the interaction between Baltic amber and daylight behind window glass, essential to understanding the mechanisms by which the material degrades in museum environments and to propose techniques for preventive conservation based on the control...

  8. A geostatistical analysis of IBTS data for age 2 North Sea haddock ( Melanogrammus aeglefinus ) considering daylight effects

    DEFF Research Database (Denmark)

    Wieland, Kai; Rivoirard, J.

    2001-01-01

    to ordinary kriging being most pronounced for years characterized by a high portion of night hauls and a low mean catch rate at night. This demonstrates that external drift kriging with a day/night indicator but preferably with time of day is capable of compensating successfully for daylight effects...... are included in the estimation without any correction for possible daylight effects. In the present study, ordinary kriging was used to correct for sampling irregularities and external drift kriging with a day/night indicator or a cosine function of time of day was applied to account additionally for diurnal...... differences in the catch rates. Only minor differences between the standard indices and the abundance estimates obtained by ordinary kriging were found. In contrast, the external drift kriging, particularly with time of day, yielded higher estimates of mean abundance for all years with the differences...

  9. Performance of skylight illuminance inside a dome shaped adobe house under composite climate at New Delhi (India: A typical zero energy passive house

    Directory of Open Access Journals (Sweden)

    Arvind Chel

    2014-06-01

    Full Text Available This paper presents annual experimental performance of pyramid shaped skylight for daylighting of a dome shaped adobe house located at solar energy park in New Delhi (India. This approach of single story dome shaped building with skylight is more useful for rural and semi-urban sectors for both office and residential buildings reducing artificial lighting energy consumption. The hourly measured data of inside and outside illuminance for three different working surface levels inside the existing rooms are presented for each month of the year. The embodied energy payback time of the skylight is also determined on the basis of lighting energy saving potential.

  10. Vibroacoustic Modeling of Mechanically Coupled Structures: Artificial Spring Technique Applied to Light and Heavy Mediums

    Directory of Open Access Journals (Sweden)

    L. Cheng

    1996-01-01

    Full Text Available This article deals with the modeling of vibrating structures immersed in both light and heavy fluids, and possible applications to noise control problems and industrial vessels containing fluids. A theoretical approach, using artificial spring systems to characterize the mechanical coupling between substructures, is extended to include fluid loading. A structure consisting of a plate-ended cylindrical shell and its enclosed acoustic cavity is analyzed. After a brief description of the proposed technique, a number of numerical results are presented. The analysis addresses the following specific issues: the coupling between the plate and the shell; the coupling between the structure and the enclosure; the possibilities and difficulties regarding internal soundproofing through modifications of the joint connections; and the effects of fluid loading on the vibration of the structure.

  11. Matching between the light spots and lenslets of an artificial compound eye system

    Science.gov (United States)

    He, Jianzheng; Jian, Huijie; Zhu, Qitao; Ma, Mengchao; Wang, Keyi

    2017-10-01

    As the visual organ of many arthropods, the compound eye has attracted a lot of attention with the advantage of wide field-of-view, multi-channel imaging ability and high agility. Extended from this concept, a new kind of artificial compound eye device is developed. There are 141 lenslets which share one image sensor distributed evenly on a curved surface, thus it is difficult to distinguish the lenslets which the light spot belongs to during calibration and positioning process. Therefore, the matching algorithm is proposed based on the device structure and the principle of calibration and positioning. Region partition of lenslet array is performed at first. Each lenslet and its adjacent lenslets are defined as cluster eyes and constructed into an index table. In the calibration process, a polar coordinate system is established, and the matching can be accomplished by comparing the rotary table position in the polar coordinate system and the central light spot angle in the image. In the positioning process, the spot is paired to the correct region according to the spots distribution firstly, and the final results is determined by the dispersion of the distance from the target point to the incident ray in the region traversal matching. Finally, the experiment results show that the presented algorithms provide a feasible and efficient way to match the spot to the lenslet, and perfectly meet the needs in the practical application of the compound eye system.

  12. Sea-level rise and refuge habitats for tidal marsh species: can artificial islands save the California Ridgway's rail?

    Science.gov (United States)

    Overton, Cory T.; Takekawa, John Y.; Casazza, Michael L.; Bui, Thuy-Vy D.; Holyoak, Marcel; Strong, Donald R.

    2014-01-01

    Terrestrial species living in intertidal habitats experience refuge limitation during periods of tidal inundation, which may be exacerbated by seasonal variation in vegetation structure, tidal cycles, and land-use change. Sea-level rise projections indicate the severity of refuge limitation may increase. Artificial habitats that provide escape cover during tidal inundation have been proposed as a temporary solution to alleviate these limitations. We tested for evidence of refuge habitat limitation in a population of endangered California Ridgway's rail (Rallus obsoletus obsoletus; hereafter California rail) through use of artificial floating island habitats provided during two winters. Previous studies demonstrated that California rail mortality was especially high during the winter and periods of increased tidal inundation, suggesting that tidal refuge habitat is critical to survival. In our study, California rail regularly used artificial islands during higher tides and daylight hours. When tide levels inundated the marsh plain, use of artificial islands was at least 300 times more frequent than would be expected if California rails used artificial habitats proportional to their availability (0.016%). Probability of use varied among islands, and low levels of use were observed at night. These patterns may result from anti-predator behaviors and heterogeneity in either rail density or availability of natural refuges. Endemic saltmarsh species are increasingly at risk from habitat change resulting from sea-level rise and development of adjacent uplands. Escape cover during tidal inundation may need to be supplemented if species are to survive. Artificial habitats may provide effective short-term mitigation for habitat change and sea-level rise in tidal marsh environments, particularly for conservation-reliant species such as California rails.

  13. Blue light hazards for ocular lesions; Risques oculaires du rayonnement bleu

    Energy Technology Data Exchange (ETDEWEB)

    Cesarini, J.P. [INSERM, Fondation Ophtalmologique A. de Rothschild, 75 - Paris (France); CES, Agents physique, AFSSET (France)

    2009-10-15

    The blue light range (400-500 nm) of visible radiation stimulates specifically cones and rods of the retina. The carried energy by these wavelengths is absorbed and transferred to specific pigments. Their energy is sufficient to produce free radicals and singlet form of oxygen. Intense sources, rich in blue light radiation, may induce, in the retina, photo-toxic lesions either limited or short-lived or photothermal lesions more or less definitive. Repeated photo-toxic lesions should be the root for the age-related maculo-pathy (A.R.M.) also called late macular degeneration (A.M.D.). As a consequence, the attention should be drawn on the potential risk linked to modern lighting as 'daylight' lamp, compact fluorescent lamps, energy saving (C.F.L.) and light-emitting diodes (L.E.D.) for which a specific vigilance should be enforced. (author)

  14. Effects of Daylight Saving Time changes on stock market volatility: a reply.

    Science.gov (United States)

    Berument, Hakan; Dogan, Nukhet

    2011-12-01

    There is a rich array of evidence that suggests that changes in sleeping patterns affect an individual's decision-making processes. A nationwide sleeping-pattern change happens twice a year when the Daylight Saving Time (DST) change occurs. Kamstra, Kramer, and Levi argued in 2000 that a DST change lowers stock market returns. This study presents evidence that DST changes affect the relationship between stock market return and volatility. Empirical evidence suggests that the positive relationship between return and volatility becomes negative on the Mondays following DST changes.

  15. Daylight illumination-color-contrast tables for full-form objects naturally illuminated objects

    CERN Document Server

    Nagel, M

    1978-01-01

    Daylight Illumination-Color-Contrast Tables for Full-form Objects is the result of a major computational project concerning the illumination, color, and contrast conditions in naturally illuminated objects. The project from which this two-chapter book is derived is originally conceived in support of the various remote sensing and image processing activities of the Deutsche Forschungs- und Versuchsanstalt für Luft- und Raumfahrt, Oberpfaffenhofen, West Germany DFVLR, in particular, those depending on the quantitative photometric and colorimetric evaluation of photographs and other environmental

  16. Thermal CFD Analysis of Tubular Light Guides

    Directory of Open Access Journals (Sweden)

    Ondřej Šikula

    2013-12-01

    Full Text Available Tubular light guides are applicable for daylighting of windowless areas in buildings. Despite their many positive indoor climate aspects they can also present some problems with heat losses and condensation. A computer CFD model focused on the evaluation of temperature distribution and air flow inside tubular light guides of different dimensions was studied. The physical model of the tested light guides of lengths more than 0.60 m proves shows that Rayleigh numbers are adequate for a turbulent air flow. The turbulent model was applied despite the small heat flux differences between the turbulent and laminar model. The CFD simulations resulted into conclusions that the growing ratio of length/diameter increases the heat transmission loss/linear transmittance as much as by 50 percent. Tubular light guides of smaller diameters have lower heat transmission losses compared to the wider ones of the same lengths with the same outdoor temperature being taken into account. The simulation results confirmed the thermal bridge effect of the tubular light guide tube inside the insulated flat roof details. The thermal transmittance of the studied light guides in the whole roof area was substituted with the point thermal bridges. This substitution gives possibility for simple thermal evaluation of the tubular light pipes in roof constructions.

  17. Development of virtual natural lighting solutions with a simplified view using lighting simulation

    NARCIS (Netherlands)

    Mangkuto, R.A.; Aries, M.B.C.; Loenen, van E.J.; Hensen, J.L.M.

    2013-01-01

    Computational building performance simulation can be employed to develop various future solutions. The development of Virtual Natural Lighting Solutions (VNLS), which are systems that artificially provide natural lighting and view comparable to those of real windows and skylights, is steered by

  18. Internet advertising of artificial tanning in Australia.

    Science.gov (United States)

    Team, Victoria; Markovic, Milica

    2006-08-01

    Artificial tanning, defined as deliberate exposure to ultraviolet rays produced by artificial tanning devices, is a new and emerging public health issue in Australia and globally. Epidemiological research suggests that artificial tanning may contribute to the incidence of melanoma, nonmelanoma skin cancer as well as other health problems. Given that Australia has a high incidence of skin cancer, we have undertaken a study to explore how artificial tanning has been promoted to its users. The aim was to analyze the completeness and accuracy of information about artificial tanning. A content analysis of web sites of tanning salons and distributors of tanning equipment in Australia was conducted. A total of 22 web sites were analyzed. None of the solarium operators or distributors of equipment provided full information about the risks of artificial tanning. Fifty-nine percent of web advertisements had no information and 41% provided only partial information regarding the risks of artificial tanning. Pictures with the image of bronze-tanned bodies, predominantly women, were used by all web advertisers. In light of the success of sun-safety campaigns in Australia, the findings of future epidemiological research on the prevalence of artificial tanning and sociological and anthropological research on why people utilize artificial tanning should be a basis for developing effective targeted health promotion on the elimination of artificial tanning in the country.

  19. Efficient light harvesting from flexible perovskite solar cells under indoor white light-emitting diode illumination

    NARCIS (Netherlands)

    Lucarelli, G.; Di Giacomo, F.; Zardetto, V.; Creatore, M.; Brown, T.M.

    2017-01-01

    This is the first report of an investigation on flexible perovskite solar cells for artificial light harvesting by using a white light-emitting diode (LED) lamp as a light source at 200 and 400 lx, values typically found in indoor environments. Flexible cells were developed using either

  20. Impact of façade window design on energy, daylighting and thermal comfort in nearly zero-energy houses

    DEFF Research Database (Denmark)

    Vanhoutteghem, Lies; Skarning, Gunnlaug Cecilie Jensen; Hviid, Christian Anker

    2015-01-01

    a solution space defined by targets for daylighting and thermal comfort. In contrast with existing guidelines, the results show an upper limit for energy savings and utilisation of solar gains in south-oriented rooms. Instead, low U-values are needed in both north- and south oriented rooms before large......Appropriate window solutions are decisive for the design of 'nearly zero-energy' buildings with healthy and comfortable indoor environment. This paper focuses on the relationship between size, orientation and glazing properties of façade windows for different side-lit room geometries in Danish...... 'nearly zero-energy' houses. The effect of these parameters on space heating demand, daylighting and thermal environment is evaluated by means of EnergyPlus and DAYSIM and presented in charts illustrating how combinations of design parameters with minimum space heating demand can be selected within...

  1. Bright-light intervention induces a dose-dependent increase in striatal response to risk in healthy volunteers

    DEFF Research Database (Denmark)

    Macoveanu, Julian; Fisher, Patrick M; Madsen, Martin K

    2016-01-01

    Bright-light interventions have successfully been used to reduce depression symptoms in patients with seasonal affective disorder, a depressive disorder most frequently occurring during seasons with reduced daylight availability. Yet, little is known about how light exposure impacts human brain...... function, for instance on risk taking, a process affected in depressive disorders. Here we examined the modulatory effects of bright-light exposure on brain activity during a risk-taking task. Thirty-two healthy male volunteers living in the greater Copenhagen area received 3weeks of bright......-light intervention during the winter season. Adopting a double-blinded dose-response design, bright-light was applied for 30minutes continuously every morning. The individual dose varied between 100 and 11.000lx. Whole-brain functional MRI was performed before and after bright-light intervention to probe how...

  2. Carotenoid deactivation in an artificial light-harvesting complex via a vibrationally hot ground state

    International Nuclear Information System (INIS)

    Savolainen, Janne; Buckup, Tiago; Hauer, Juergen; Jafarpour, Aliakbar; Serrat, Carles; Motzkus, Marcus; Herek, Jennifer L.

    2009-01-01

    Ultrafast relaxation of a carotenoid in an artificial light-harvesting complex has been studied by transient absorption spectroscopy. The transient signal amplitudes at several wavelengths as well as the amplitudes of the underlying species associated spectra (SAS) are analysed for several excitation energies ranging over more than two orders of magnitude (10 nJ/pulse up to 3000 nJ/pulse). Our analysis shows that the contribution from the so-called S* signal on the long-wavelength side of the first allowed S 0 → S 2 transition has a markedly different excitation energy dependence and saturation behaviour than the electronic excited state S 1 . These observations are modelled and explained in terms of a two-photon excitation of a vibrationally hot ground state via an impulsive stimulated Raman scattering (ISRS). The experimental observations of the varying pulse energy dependencies of different excited state species are supported by an analysis based on a density-matrix formalism

  3. Estimating Photosynthetic Radiation Use Efficiency Using Incident Light and Photosynthesis of Individual Leaves

    OpenAIRE

    ROSATI, A.; DEJONG, T. M.

    2003-01-01

    It has been theorized that photosynthetic radiation use efficiency (PhRUE) over the course of a day is constant for leaves throughout a canopy if leaf nitrogen content and photosynthetic properties are adapted to local light so that canopy photosynthesis over a day is optimized. To test this hypothesis, ‘daily’ photosynthesis of individual leaves of Solanum melongena plants was calculated from instantaneous rates of photosynthesis integrated over the daylight hours. Instantaneous photosynthes...

  4. Urban lighting, light pollution and society

    CERN Document Server

    Meier, Josiane; Krause, Katharina; Pottharst, Merle

    2014-01-01

    After decades "in the shadows", urban lighting is re-emerging as a matter of public debate. Long-standing truths are increasingly questioned as a confluence of developments affects lighting itself and the way it is viewed. Light has become an integral element of place-making and energy-saving initiatives alike. Rapidly evolving lighting technologies are opening up new possibilities, but also posing new challenges to planners, and awareness is growing that artificial illumination is not purely benign but can actually constitute a form of pollution. As a result, public policy frameworks, incentives and initiatives are undergoing a phase of innovation and change that will affect how cities are lit for years to come. The first comprehensive compilation of current scientific discussions on urban lighting and light pollution from a social science and humanities perspective, Urban Lighting, Light Pollution and Society contributes to an evolving international debate on an increasingly controversial topic. The contrib...

  5. How is Workers' Mood Affected by Workplace Lighting?

    Science.gov (United States)

    Tonello, Graciela

    The aim of the study was to investigate to what extent variations in natural daylight, as well as in indoor lighting and decoration, would affect the mood of people working indoor. It was assumed that such an impact would be moderated by the personality characteristics of the individuals. The study was carried out in northern Argentina in workplaces consisting mostly of open plan offices, but also some rooms for one or two persons, and a factory plant were included. About 20 per cent completely lacked windows. In spite of the considerable variations in day length, ranging from ten-and-a-half hours in June to fourteen hours in December, no overall seasonal variations in mood could be established. One obvious reason for this may have been the frequent use of shading devices which reduced the impact of the variations in natural daylight between summer and winter. On the other hand, the differences between the interior environments in terms of lighting and decoration did seem to have at least some impact. Both analyses of regression and variance showed interior decoration to be the most important from the emotional point of view. The participants throughout, reported a more positive mood in the colourful environments. The difference was consistent over the year but became significant only during autumn and winter. Individuals of type B (few signs of tension) reported a more positive emotional status throughout the year than those of type A, which is in line with previous results linking type A to anger and hostility.

  6. Light Pollution and Wildlife

    Science.gov (United States)

    Duffek, J.

    2008-12-01

    for Educational Program IYA Dark Skies Education Session Fall American Geophysical Union San Francisco, December 15-19, 2008 Light Pollution and Wildlife This is a very exciting time to be a part of the mission to keep the nighttime skies natural. The International Year of Astronomy (IYA) 2009 is developing programs for all areas of Dark Skies Awareness. For many years the issue of light pollution focused on the impact to the astronomy industry. While this is an important area, research has shown that light pollution negatively impacts wildlife, their habitat, human health, and is a significant waste of energy. Since the message and impact of the effects of light pollution are much broader now, the message conveyed to the public must also be broader. Education programs directed at youth are a new frontier to reach out to a new audience about the adverse effects of too much artificial light at night. The International Dark-Sky Association (IDA) has developed educational presentations using the National Science Teachers Association Education Standards. These programs focus on youth between the ages of 5 to 17exploring new territory in the education of light pollution. The IDA education programs are broken down into three age groups; ages 5-9, 8-13, 12 and older. The presentations come complete with PowerPoint slides, discussion notes for each slide, and workbooks including age appropriate games to keep young audiences involved. A new presentation reflects the growing area of interest regarding the effects of too much artificial light at night on wildlife. This presentation outlines the known problems for ecosystems caused by artificial light at night. Insects are attracted to artificial lights and may stay near that light all night. This attraction interferes with their ability to migrate, mate, and look for food. Such behavior leads to smaller insect populations. Fewer insects in turn affect birds and bats, because they rely on insects as a food source. The IDA

  7. Lightness dependence of achromatic loci in color-appearance coordinates

    Directory of Open Access Journals (Sweden)

    Ichiro eKuriki

    2015-02-01

    Full Text Available Shifts in the appearance of color under different illuminant chromaticity are known to be incomplete, and fit nicely with a simple linear transformation of cone responses that aligns the achromatic points under two illuminants. Most chromaticity-transfer functions with von-Kries-like transformations use only one set of values to fit the color shifts from one illuminant to another. However, an achromatic point shifts its chromaticity depending on the lightness of the test stimulus. This lightness dependence of the achromatic-point locus is qualitatively similar to a phenomenon known as the Helson-Judd effect. The present study suggests that the lightness dependency of achromatic points appears to be a general trend, which is supported by the results from deriving the optimal von-Kries coefficients for different lightness levels that best fit the color shifts under different illuminant chromaticities. Further, we report that such a lightness dependence of the achromatic-point loci can be represented simply as a straight line in coordinates defined using color-appearance models such as CIECAM when normalized for daylight.

  8. Pollination by nocturnal Lepidoptera, and the effects of light pollution: a review.

    Science.gov (United States)

    MacGregor, Callum J; Pocock, Michael J O; Fox, Richard; Evans, Darren M

    2015-06-01

    1. Moths (Lepidoptera) are the major nocturnal pollinators of flowers. However, their importance and contribution to the provision of pollination ecosystem services may have been under-appreciated. Evidence was identified that moths are important pollinators of a diverse range of plant species in diverse ecosystems across the world. 2. Moth populations are known to be undergoing significant declines in several European countries. Among the potential drivers of this decline is increasing light pollution. The known and possible effects of artificial night lighting upon moths were reviewed, and suggest how artificial night lighting might in turn affect the provision of pollination by moths. The need for studies of the effects of artificial night lighting upon whole communities of moths was highlighted. 3. An ecological network approach is one valuable method to consider the effects of artificial night lighting upon the provision of pollination by moths, as it provides useful insights into ecosystem functioning and stability, and may help elucidate the indirect effects of artificial light upon communities of moths and the plants they pollinate. 4. It was concluded that nocturnal pollination is an ecosystem process that may potentially be disrupted by increasing light pollution, although the nature of this disruption remains to be tested.

  9. Development and Performance Evaluation of Light Shelves Using Width-Adjustable Reflectors

    Directory of Open Access Journals (Sweden)

    Heangwoo Lee

    2018-01-01

    Full Text Available In recent years, there has been an increase in the consumption of energy for lighting purposes, which has led to an increase in the number of studies being conducted on this subject. Most studies have focused on light shelves, which are daylighting systems used for reducing the lighting energy required for the interiors of buildings. However, the existing light shelves cannot actively deal with external environmental factors, which often lead to an infringement of the right to light during the night when the performance of the light shelf deteriorates. Therefore, in this study, we propose a light shelf with a width-adjustable reflector and verify its validity using a testbed. The reflector of the proposed light shelf system is modularized so that the length can be adjusted in stages. The optimum width of the light shelf is calculated in terms of the energy reduction and uniformity ratio improvement, and the obtained optimum width is varied depending on the season. We find that the width-adjustable reflector can save 20% and 21.6% more lighting energy than light shelves with fixed reflector widths of 0.3 m and 0.6 m, respectively.

  10. Autonomous shading and light deflection systems; Autarke Sonnenschutz- und Lichtlenksysteme

    Energy Technology Data Exchange (ETDEWEB)

    Klotz, F.H. [Zentrum fuer Sonnenenergie- und Wasserstoff-Forschung Baden-Wuerttemberg (ZSW), Stuttgart (Germany)

    1998-02-01

    The motivations for solar control and daylighting systems at buildings are the reduced use of conventional energy and the improved comfort, for living as well as for working. Light guiding devices can be used in order to obtain daylight still in the deep interior of a building or in order to illuminate special targets. Due to the daily and seasonal changes in the Sun`s position, these devices must be constantly adapted. Using simple and reliable passive thermohydraulic drive technology, many applications for daylighting systems become feasible which were of merely theoretical interest in the past. ZSW has started an initiative for the development of such building-integrated solar systems. This report shows the latest results. (orig.) [Deutsch] Energie- und Umweltaspekte sowie neuere Erkenntnisse der Chronobiologie fordern eine intelligentere und effizientere Architektur und Gebaeudetechnik. Eine zentrale Rolle spielen dabei die transparenten Bauteile (Fenster, Glasfassaden, Atrien, Oberlichter, etc.), da dort der hauptsaechliche Energieaustausch (Waerme, Luft) stattfindet. Eine wirksame Kontrolle dieses Energieflusses - im Kontext der saisonalen und diurnalen Schwankungn der Sonneneinstrahlung - ist der Schluessel zur Reduktion des Gebaeudeenergiebedarfs (Heizung, Kuehlung, Beleuchtung, Lueftung) und der Steigerung des visuellen und thermischen Komforts. Es wurde eine Entwicklungsinitiative fuer passive thermohydraulisch gefuehrte Sonnenschutz- und Lichtlenksysteme gestartet, die durch die Sonne selbst mit Energie versorgt und reguliert werden und damit vollkommen autark sind. Hieraus ergibt sich ein hohes Kostenreduktionspotential fuer den Betrieb solcher Anlagen. Ein Meilenstein dieser Entwicklungen ist der von ZSW fuer die Sonnenlichtlenkung entwickelte erste passive zweiachsig nachgefuehrte Heliostat, welcher bereits seit 16 Monaten stoerungsfrei in Betrieb ist. (orig.)

  11. Luminous effectiveness of tubular light-guides in tropics

    Energy Technology Data Exchange (ETDEWEB)

    Darula, Stanislav; Kittler, Richard; Kocifaj, Miroslav [ICA, Slovak Academy of Sciences, 9, Dubravska Road, 845 03 Bratislava (Slovakia)

    2010-11-15

    Novel tubular light-guides with a transparent hemispherical cupola placed on an unobstructed flat roof collect all sunlight and skylight available at ground level year round. This advantage is heightened in the dry and sunny tropical regions where the sun rises to very high altitudes and often the hours of sunshine last throughout the whole day. Hollow light-guides with very high inner specular reflectances can transport sunbeams downward into the windowless building core very effectively. Due to the tube's diameter and length and multiple reflections, complex illuminance patterns are produced on the underside of the tube, i.e. on top of the glazed ceiling aperture that illuminates the interior space or its working plane. This paper discusses several daylight conditions in tropical interiors illuminated by tubular light-guides. The recently published HOLIGILM calculation program and the user-friendly tool HOLIGILM 4.2 have facilitated the production of this paper. (author)

  12. Does light attract piglets to the creep area?

    DEFF Research Database (Denmark)

    Larsen, Mona Lilian Vestbjerg; Pedersen, Lene Juul

    2015-01-01

    Hypothermia, experienced by piglets, has been related to piglet deaths and high and early use of a heated creep area is considered important to prevent hypothermia. The aims of the present study were to investigate how a newly invented radiant heat source, eHeat, would affect piglets' use...... of the creep area and whether light in the creep area works as an attractant on piglets. A total of 39 sows, divided between two batches, were randomly distributed to three heat source treatments: (1) standard infrared heat lamp (CONT, n=19), (2) eHeat with light (EL, n=10) and (3) eHeat without light (ENL, n......=10). Recordings of piglets' use of the creep area were made as scan sampling every 10 min for 3 h during two periods, one in daylight (0900 to 1200 h) and one in darkness (2100 to 2400 h), on day 1, 2, 3, 7, 14 and 21 postpartum. On the same days, piglets were weighted. Results showed an interaction...

  13. The impact of the daylight saving time on electricity consumption-A case study from Jordan

    International Nuclear Information System (INIS)

    Awad Momani, Mohammad; Yatim, Baharudin; Ali, Mohd Alauddin Mohd

    2009-01-01

    The paper examines the impact of daylight saving time (DST) on electricity consumption in Jordan. Two types of analysis were done: the first analysis examines the impact of DST on the lighting loads based on a survey study made for residential and commercial sectors. The second examines the impact of DST on the over all electricity generation through analyzing the daily load curves (DLCs) before and after the DST onset and removal in 2000 and 2007. The results show that the application of DST during the year 2000 saves the electricity used for illumination by -0.73% but it increases the overall generation at the onset and removal of DST by 0.5% and 1.4% due to increase in the heating and cooling loads. The analysis of DLCs during the year 2007 shows similar effects as in the year 2000 except during the early morning period at the DST onset where DST decreases the demand during this time. The analysis shows that DST decreases the electricity demand at DST onset by 0.2% and increases it at DST removal by 0.3%. A possible decrease in the electricity consumption may take place if the DST is implemented from April to end of August.

  14. An artificial ecosystem model used in the study of social, economic and technological dynamics: An artificial electrical energy market

    International Nuclear Information System (INIS)

    Arjona, D.

    1998-01-01

    This paper will present the artificial ecosystem as a tool, in the development of multi agent models for the simulation of economic and technological dynamics (as well as other possible applications). This tool is based on the mechanics of an artificial society and consists of autonomous artificial agents that interact with individuals that have different characteristics and behavior and other that have a similar conduct to their own. Initial conditions are assumed not to be controllable, however they can be influenced. The importance of the concept of the ecosystem is in understanding great units in the light of their own components which are relevant for the analysis and become interdependent among themselves and with other essential components that hold the total operation of the system. Ideas for the development of a simulation model based on autonomous intelligent agents are presented. These agents will have a brain that is based on artificial intelligence technologies. The Sand Kings Simulation Model, an artificial ecosystem model developed by the author, is described as well as the application of artificial intelligence to this artificial life model. An application to a real life problem is also offered as an artificial energy market that is currently being developed by the author is described

  15. 50 CFR 27.73 - Artificial lights.

    Science.gov (United States)

    2010-10-01

    ... light, or automotive headlights for the purpose of spotting, locating, or taking any animal within the boundaries of any national wildlife refuge or along rights-of-way for public or private roads within a...

  16. Blue-enriched office light competes with natural light as a zeitgeber.

    Science.gov (United States)

    Vetter, Céline; Juda, Myriam; Lang, Dieter; Wojtysiak, Andreas; Roenneberg, Till

    2011-09-01

    Circadian regulation of human physiology and behavior (eg, body temperature or sleep-timing), depends on the "zeitgeber" light that synchronizes them to the 24-hour day. This study investigated the effect of changing light temperature at the workplace from 4000 Kelvin (K) to 8000 K on sleep-wake and activity-rest behavior. An experimental group (N=27) that experienced the light change was compared with a non-intervention group (N=27) that remained in the 4000 K environment throughout the 5-week study period (14 January to 17 February). Sleep logs and actimetry continuously assessed sleep-wake behavior and activity patterns. Over the study period, the timing of sleep and activity on free days steadily advanced parallel to the seasonal progression of sunrise in the non-intervention group. In contrast, the temporal pattern of sleep and activity in the experimental group remained associated with the constant onset of work. The results suggest that artificial blue-enriched light competes with natural light as a zeitgeber. While subjects working under the warmer light (4000 K) appear to entrain (or synchronize) to natural dawn, the subjects who were exposed to blue-enriched (8000 K) light appear to entrain to office hours. The results confirm that light is the dominant zeitgeber for the human clock and that its efficacy depends on spectral composition. The results also indicate that blue-enriched artificial light is a potent zeitgeber that has to be used with diligence.

  17. Modeling Performance of an Airborne Infrared Sensor Used by a Man-in-the-Loop in Tactical Aircraft during Daylight Operations

    National Research Council Canada - National Science Library

    Harder, James

    1998-01-01

    .... The best monochromatic tactical aircraft displays are contrast limited during daylight operations and are able to reproduce only a fraction of the available dynamic range of current generation IR imaging sensors...

  18. Office worker response to an automated venetian blind and electric lighting system: A pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Vine, E.; Lee, E.; Clear, R.; DiBartolomeo, D.; Selkowitz, S.

    1998-03-01

    A prototype integrated, dynamic building envelope and lighting system designed to optimize daylight admission and solar heat gain rejection on a real-time basis in a commercial office building is evaluated. Office worker response to the system and occupant-based modifications to the control system are investigated to determine if the design and operation of the prototype system can be improved. Key findings from the study are: (1) the prototype integrated envelope and lighting system is ready for field testing, (2) most office workers (N=14) were satisfied with the system, and (3) there were few complaints. Additional studies are needed to explain how illuminance distribution, lighting quality, and room design can affect workplans illuminance preferences.

  19. Windows and lighting program

    Energy Technology Data Exchange (ETDEWEB)

    1990-06-01

    More than 30% of all energy use in buildings is attributable to two sources: windows and lighting. Together they account for annual consumer energy expenditures of more than $50 billion. Each affects not only energy use by other major building systems, but also comfort and productivity -- factors that influence building economics far more than does direct energy consumption alone. Windows play a unique role in the building envelope, physically separating the conditioned space from the world outside without sacrificing vital visual contact. Throughout the indoor environment, lighting systems facilitate a variety of tasks associated with a wide range of visual requirements while defining the luminous qualities of the indoor environment. Windows and lighting are thus essential components of any comprehensive building science program. Despite important achievements in reducing building energy consumption over the past decade, significant additional savings are still possible. These will come from two complementary strategies: (1) improve building designs so that they effectively apply existing technologies and extend the market penetration of these technologies; and (2) develop advanced technologies that increase the savings potential of each application. Both the Windows and Daylighting Group and the Lighting System Research Group have made substantial contributions in each of these areas, and continue to do so through the ongoing research summarized here. 23 refs., 16 figs.

  20. Daylight saving time can decrease the frequency of wildlife–vehicle collisions

    Science.gov (United States)

    Ellis, William A.; FitzGibbon, Sean I.; Barth, Benjamin J.; Niehaus, Amanda C.; David, Gwendolyn K.; Taylor, Brendan D.; Matsushige, Helena; Melzer, Alistair; Bercovitch, Fred B.; Carrick, Frank; Jones, Darryl N.; Dexter, Cathryn; Gillett, Amber; Predavec, Martin; Lunney, Dan

    2016-01-01

    Daylight saving time (DST) could reduce collisions with wildlife by changing the timing of commuter traffic relative to the behaviour of nocturnal animals. To test this idea, we tracked wild koalas (Phascolarctos cinereus) in southeast Queensland, where koalas have declined by 80% in the last 20 years, and compared their movements with traffic patterns along roads where they are often killed. Using a simple model, we found that DST could decrease collisions with koalas by 8% on weekdays and 11% at weekends, simply by shifting the timing of traffic relative to darkness. Wildlife conservation and road safety should become part of the debate on DST. PMID:27881767