WorldWideScience

Sample records for model solar hot

  1. Analysis, Modeling and Optimum Design of Solar Domestic Hot Water Systems

    DEFF Research Database (Denmark)

    Qin, Lin

    1999-01-01

    This study focus on the analysis, modeling and simulation of solar domestic hot water(DHW) systems. Problems related to the system operation such as input weather data and hot water load conditions are also investigated.In order to investigate the heat loss as part of the total heat load, dynamic...... model of distribution network is developed and simulations are carried out for typical designed circulation type of distribution networks. For dynamic simulation of thermosyphon and drain-back solar DHW systems, thermosyphon loop model and drain-back tank model are put forward. Based on the simulations...

  2. Solar Hot Water Heater

    Science.gov (United States)

    1978-01-01

    The solar panels pictured below, mounted on a Moscow, Idaho home, are part of a domestic hot water heating system capable of providing up to 100 percent of home or small business hot water needs. Produced by Lennox Industries Inc., Marshalltown, Iowa, the panels are commercial versions of a collector co-developed by NASA. In an effort to conserve energy, NASA has installed solar collectors at a number of its own facilities and is conducting research to develop the most efficient systems. Lewis Research Center teamed with Honeywell Inc., Minneapolis, Minnesota to develop the flat plate collector shown. Key to the collector's efficiency is black chrome coating on the plate developed for use on spacecraft solar cells, the coating prevents sun heat from "reradiating," or escaping outward. The design proved the most effective heat absorber among 23 different types of collectors evaluated in a Lewis test program. The Lennox solar domestic hot water heating system has three main components: the array of collectors, a "solar module" (blue unit pictured) and a conventional water heater. A fluid-ethylene glycol and water-is circulated through the collectors to absorb solar heat. The fluid is then piped to a double-walled jacket around a water tank within the solar module.

  3. Simulation programs for ph.D. study of analysis, modeling and optimum design of solar domestic hot water systems

    Energy Technology Data Exchange (ETDEWEB)

    Lin Qin

    1998-12-31

    The design of solar domestic hot water (DHW) systems is a complex process, due to characteristics inherent in the solar heating technology. Recently, computer simulation has become a widely used technique to improve the understanding of the thermal processes in such systems. One of the main objects of the Ph.D. study of `Analysis, Modelling and optimum Design of Solar Domestic Hot Water Systems` is to develop and verify programs for carrying out the simulation and evaluation of the dynamic performance of solar DHW systems. During this study, simulation programs for hot water distribution networks and for certain types of solar DHW systems were developed. (au)

  4. Residential solar hot water

    Energy Technology Data Exchange (ETDEWEB)

    1982-06-01

    This report examines the feasibility of using solar energy to preheat domestic water coming from the city supply at a temperature of approximately 4{degree}C. Four solar collectors totalling 7 m{sup 2} were installed on a support structure facing south at an angle of 60{degree} from the horizontal. The system worked most efficiently in the spring and early summer when the combination of long hours of sunshine, clean air and clear skies allowed for maximum availability of solar radiation. Performance dropped in late summer and fall mainly due to cloudier weather conditions. The average temperature in the storage tank over the 10 months of operation was 42{degree}C, ranging from a high of 83{degree}C in July to a low of 6{degree}C in November. The system provided a total of 7.1 GJ, which is approximately one-third the annual requirement for domestic hot water heating. At the present time domestic use of solar energy to heat water does not appear to be economically viable. High capital costs are the main problem. As a solar system with present day technology can only be expected to meet half to two-thirds of the hot water energy demand the savings are not sufficient for the system to pay for itself within a few years. 5 figs.

  5. Simulation Programs for Ph.D. Study of Analysis, Modeling and Optimum Design of Solar Domestic Hot Water Systems

    DEFF Research Database (Denmark)

    Qin, Lin

    1999-01-01

    The design of solar domestic hot water system is a complex process, due to characteristics inherent in solar heating technology. Recently, computer simulation has become a widely used technique to improve the understanding of the thermal processes in such systems. This report presents the detaile...... programs or units that were developed in the Ph.D study of " Analysis, Modeling and Optimum Design of Solar Domestic Hot Water Systems"....

  6. Solar 'hot spots' are still hot

    Science.gov (United States)

    Bai, Taeil

    1990-01-01

    Longitude distributions of solar flares are not random but show evidence for active zones (or hot spots) where flares are concentrated. According to a previous study, two hot spots in the northern hemisphere, which rotate with a synodic period of about 26.72 days, produced the majority of major flares, during solar cycles 20 and 21. The more prominent of these two hot spots is found to be still active during the rising part of cycle 22, producing the majority of northern hemisphere major flares. The synodic rotation period of this hot spot is 26.727 + or - 0.007 days. There is also evidence for hot spots in the southern hemisphere. Two hot spots separated by 180 deg are found to rotate with a period of 29.407 days, with one of them having persisted in the same locations during cycles 19-22 and the other, during cycles 20-22.

  7. Solar hot spots are still hot

    International Nuclear Information System (INIS)

    Bai, T.

    1990-01-01

    Longitude distributions of solar flares are not random but show evidence for active zones (or hot spots) where flares are concentrated. According to a previous study, two hot spots in the northern hemisphere, which rotate with a synodic period of about 26.72 days, produced the majority of major flares, during solar cycles 20 and 21. The more prominent of these two hot spots is found to be still active during the rising part of cycle 22, producing the majority of northern hemisphere major flares. The synodic rotation period of this hot spot is 26.727 + or - 0.007 days. There is also evidence for hot spots in the southern hemisphere. Two hot spots separated by 180 deg are found to rotate with a period of 29.407 days, with one of them having persisted in the same locations during cycles 19-22 and the other, during cycles 20-22. 14 refs

  8. Solar Technician Program Blows Hot

    Science.gov (United States)

    Ziegler, Peg Moran

    1977-01-01

    A training program for solar heating technicians was initiated at Sonoma State College's School of Environmental Studies for CETA applicants. Among the projects designed and built were a solar alternative energy center, a solar hot water system, and a solar greenhouse. (MF)

  9. Analysis, modeling and optimum design of solar domestic hot water systems

    Energy Technology Data Exchange (ETDEWEB)

    Lin Qin

    1998-12-31

    The object of this study was dynamic modeling, simulation and optimum design of solar DHW (domestic hot water) systems, with respect to different whether conditions, and accurate dynamic behaviour of the heat load. Special attention was paid to systems with thermosyphon and drain-back design. The solar radiation in Beijing (China) and in Denmark are analyzed both by theoretical calculations and the analysis of long-term measurements. Based on the weather data from the Beijing Meteorological Station during the period of 1981-1993, a Beijing Test Reference Year has been formulated by means of statistical analysis. A brief introduction about the Danish Test Reference Year and the Design Reference Year is also presented. In order to investigate the heat loss as a part of the total heat load, dynamic models for distribution networks have been developed, and simulations have been carried out for typically designed distribution networks of the circulation type. The influence of operation parameters such as the tank outlet temperature, the hot-water load and the load pattern, on the heat loss from the distribution networks in presented. It was found that the tank outlet temperature has a significant influence on the heat loss from a circulation type of distribution network, while the hot-water load and the load pattern have no obvious effect. Dynamic models of drain-back tanks, both as a separated tank and combined with a mantle tank, have been developed and presented. Models of the other basic components commonly used in solar DHW systems, such as flat-plate collectors, connection pipes, storage tanks with a heat exchanger spiral, and controllers, are also described. (LN) 66 refs.

  10. Analytical modeling of the temporal evolution of hot spot temperatures in silicon solar cells

    Science.gov (United States)

    Wasmer, Sven; Rajsrima, Narong; Geisemeyer, Ino; Fertig, Fabian; Greulich, Johannes Michael; Rein, Stefan

    2018-03-01

    We present an approach to predict the equilibrium temperature of hot spots in crystalline silicon solar cells based on the analysis of their temporal evolution right after turning on a reverse bias. For this end, we derive an analytical expression for the time-dependent heat diffusion of a breakdown channel that is assumed to be cylindrical. We validate this by means of thermography imaging of hot spots right after turning on a reverse bias. The expression allows to be used to extract hot spot powers and radii from short-term measurements, targeting application in inline solar cell characterization. The extracted hot spot powers are validated at the hands of long-term dark lock-in thermography imaging. Using a look-up table of expected equilibrium temperatures determined by numerical and analytical simulations, we utilize the determined hot spot properties to predict the equilibrium temperatures of about 100 industrial aluminum back-surface field solar cells and achieve a high correlation coefficient of 0.86 and a mean absolute error of only 3.3 K.

  11. Basics of Solar Heating & Hot Water Systems.

    Science.gov (United States)

    American Inst. of Architects, Washington, DC.

    In presenting the basics of solar heating and hot water systems, this publication is organized from the general to the specific. It begins by presenting functional and operational descriptions of solar heating and domestic hot water systems, outlining the basic concepts and terminology. This is followed by a description of solar energy utilization…

  12. OUT Success Stories: Solar Hot Water Technology

    International Nuclear Information System (INIS)

    Clyne, R.

    2000-01-01

    Solar hot water technology was made great strides in the past two decades. Every home, commercial building, and industrial facility requires hot water. DOE has helped to develop reliable and durable solar hot water systems. For industrial applications, the growth potential lies in large-scale systems, using flat-plate and trough-type collectors. Flat-plate collectors are commonly used in residential hot water systems and can be integrated into the architectural design of the building

  13. OUT Success Stories: Solar Hot Water Technology

    Science.gov (United States)

    Clyne, R.

    2000-08-01

    Solar hot water technology was made great strides in the past two decades. Every home, commercial building, and industrial facility requires hot water. DOE has helped to develop reliable and durable solar hot water systems. For industrial applications, the growth potential lies in large-scale systems, using flat-plate and trough-type collectors. Flat-plate collectors are commonly used in residential hot water systems and can be integrated into the architectural design of the building.

  14. Solar Energy for Space Heating & Hot Water.

    Science.gov (United States)

    Energy Research and Development Administration, Washington, DC. Div. of Solar Energy.

    This pamphlet reviews the direct transfer of solar energy into heat, particularly for the purpose of providing space and hot water heating needs. Owners of buildings and homes are provided with a basic understanding of solar heating and hot water systems: what they are, how they perform, the energy savings possible, and the cost factors involved.…

  15. Modelling Hot Air Balloons.

    Science.gov (United States)

    Brimicombe, M. W.

    1991-01-01

    A macroscopic way of modeling hot air balloons using a Newtonian approach is presented. Misleading examples using a car tire and the concept of hot air rising are discussed. Pressure gradient changes in the atmosphere are used to explain how hot air balloons work. (KR)

  16. Theoretical model and experimental validation of a direct-expansion solar assisted heat pump for domestic hot water applications

    International Nuclear Information System (INIS)

    Moreno-Rodríguez, A.; González-Gil, A.; Izquierdo, M.; Garcia-Hernando, N.

    2012-01-01

    This paper has shown the development of a theoretical model to determine the operating parameters and consumption of a domestic hot water (DHW) installation, which uses a direct-expansion solar assisted heat pump (DXSAHP) with refrigerant R-134a, a compressor with a rated capacity of 1.1 kW and collectors with a total area of 5.6 m 2 . The model results have been compared and validated the experimental results obtained with the equipment installed at the University Carlos III, South of Madrid. The analysis was conducted over the course of a year, and the results have been represented depending on the meteorological and process variables of several representative days. Taking into account the thermal losses of the installation and the dependency on the operating conditions, the acquired experimental coefficient of performance is between 1.7 and 2.9, while the DHW tank temperature over the course of the study is 51 °C. -- Highlights: ► The study aims to present a new theoretical model and an experimental validation. ► The experimental COP vary between 1.7 and 2.9 (max. condensation temperature 57 °C). ► The operating parameters respond to the solar radiation. The COP may increase up to 50%. ► The useful surface area varies between 50% and 85% of the total surface. ► The system stops if conditions exceed the maximum value of the absorbed heat.

  17. Design data brochure: Solar hot air heater

    Science.gov (United States)

    1978-01-01

    The design, installation, performance, and application of a solar hot air heater for residential, commercial and industrial use is reported. The system has been installed at the Concho Indian School in El Reno, Oklahoma.

  18. Design data brochure: Solar hot water system

    Science.gov (United States)

    1978-01-01

    A design calculation is detailed for a single-family residence housing a family of four in a nonspecific geographical area. The solar water heater system is designed to provide 80 gallons of 140 F hot water per day.

  19. Prototype solar heating and hot water system

    Science.gov (United States)

    1977-01-01

    Progress is reported in the development of a solar heating and hot water system which uses a pyramidal optics solar concentrator for heating, and consists of the following subsystems: collector, control, transport, and site data acquisition. Improvements made in the components and subsystems are discussed.

  20. BC SEA Solar Hot Water Acceleration project

    Energy Technology Data Exchange (ETDEWEB)

    Harris, N.C. [BC Sustainable Energy Association, Victoria, BC (Canada)

    2005-07-01

    Although solar hot water heating is an environmentally responsible technology that reduces fossil fuel consumption and helps mitigate global climate change, there are many barriers to its widespread use. Each year, domestic water heating contributes nearly 6 million tonnes of carbon dioxide towards Canada's greenhouse gas emissions. The installation of solar water heaters can eliminate up to 2 tonnes of carbon dioxide emissions per household. The BC SEA Solar Hot Water Acceleration project was launched in an effort to demonstrate that the technology has the potential to be widely used in homes and businesses across British Columbia. One of the main barriers to the widespread use of solar hot water heating is the initial cost of the system. Lack of public awareness and understanding of the technology are other barriers. However, other jurisdictions around the world have demonstrated that the use of renewables are the product of conscious policy decisions, including low-cost financing and other subsidies that have created demand for these technologies. To this end, the BC SEA Solar Hot Water Acceleration project will test the potential for the rapid acceleration of solar water heating in pilot communities where barriers are removed. The objective of the project is to install 100 solar water systems in homes and 25 in businesses and institutions in communities in British Columbia by July 2007. The project will explore the financial barriers to the installation of solar hot water systems and produce an action plan to reduce these barriers. In addition to leading by example, the project will help the solar energy marketplace, mitigate climate change and improve energy efficiency.

  1. Solar action: solar hot water in The Netherlands

    International Nuclear Information System (INIS)

    Van de Water, Adrie

    2001-01-01

    This paper focuses on the use of solar hot water systems in the Netherlands, and reports on the Dutch Solar Domestic Hot Water System agreement signed in 1999 and set up to enhance the development of the market for solar domestic hot water (SDHW) systems and their application as a sustainable energy source. The Dutch Thermal Solar Energy Programme's objectives and goals, the subsidy schemes for thermal solar energy administered by Senter - an agency of the Ministry of Economic Affairs (MEA), and the project-based and individual approaches to boosting the sales of SDHW systems are examined. Large system sales, the targeting of consumers via a national campaign, and national publicity using the slogan 'Sustainable energy. Goes without saying' commissioned by the MEA are discussed along with the support shown by the Dutch power distribution companies for SDHW systems, marketing aspects, and the outlook for sales of SDHW systems

  2. Modeling and characterization of double resonant tunneling diodes for application as energy selective contacts in hot carrier solar cells

    Science.gov (United States)

    Jehl, Zacharie; Suchet, Daniel; Julian, Anatole; Bernard, Cyril; Miyashita, Naoya; Gibelli, Francois; Okada, Yoshitaka; Guillemolles, Jean-Francois

    2017-02-01

    Double resonant tunneling barriers are considered for an application as energy selective contacts in hot carrier solar cells. Experimental symmetric and asymmetric double resonant tunneling barriers are realized by molecular beam epitaxy and characterized by temperature dependent current-voltage measurements. The negative differential resistance signal is enhanced for asymmetric heterostructures, and remains unchanged between low- and room-temperatures. Within Tsu-Esaki description of the tunnel current, this observation can be explained by the voltage dependence of the tunnel transmission amplitude, which presents a resonance under finite bias for asymmetric structures. This effect is notably discussed with respect to series resistance. Different parameters related to the electronic transmission of the structure and the influence of these parameters on the current voltage characteristic are investigated, bringing insights on critical processes to optimize in double resonant tunneling barriers applied to hot carrier solar cells.

  3. Retrofitting Conventional Electric Domestic Hot Water Heaters to Solar Water Heating Systems in Single-Family Houses—Model Validation and Optimization

    Directory of Open Access Journals (Sweden)

    Luis R. Bernardo

    2013-02-01

    Full Text Available System cost reductions and development of standardised plug-and-function systems are some of the most important goals for solar heating technology development. Retrofitting hot water boilers in single-family houses when installing solar collectors has the potential to significantly reduce both material and installation costs. In this study, the TRNSYS simulation models of the retrofitting solar thermal system were validated against measurements. Results show that the validated models are in good agreement with measurements. On an annual basis a deviation of 2.5% out of 1099 kWh was obtained between the auxiliary energy from results and from the simulation model for a complete system. Using the validated model a system optimization was carried out with respect to control strategies for auxiliary heating, heat losses and volume of auxiliary storage. A sensitivity analysis was carried out regarding different volumes of retrofitted hot water boiler, DHW profiles and climates. It was estimated that, with adequate improvements, extended annual solar fractions of 60%, 78% and 81% can be achieved for Lund (Sweden, Lisbon (Portugal and Lusaka (Zambia, respectively. The correspondent collector area was 6, 4 and 3 m2, respectively. The studied retrofitted system achieves a comparable performance with conventional solar thermal systems with the potential to reduce the investment cost.

  4. Collective solar hot water: best practices

    International Nuclear Information System (INIS)

    Beutin, Philippe; Grouzard, Patrice; Coroller, Francoise

    2005-10-01

    This brochure, edited by ADEME, the French office for energy management and sustainable development, gives a collection of good practices concerning the selection and installation of collective solar water heating systems in France. A first note presents the Garantie de Resultats solaires (GRS - Guarantee of Solar Results), a kind of certification that gives a long term guarantee of the annual solar energy produced quantity as a function of the hot water consumption. An overview of the collective solar market is given, followed by informations on the financial incentives for feasibility studies and installations, the technical design and optimization of a collective solar project, its economic assessment, etc. Numerous examples of collective of solar heating operations in collective buildings are presented, in various regions of France, in the east (Alsace), the center (Auvergne, Ile de France (Paris region)), and the south (Languedoc-Roussillon, Midi-Pyrennes, PACA), giving technical data, financing, partnerships, etc

  5. Solar-powered hot-air system

    Science.gov (United States)

    1979-01-01

    Solar-powered air heater supplies part or all of space heating requirements of residential or commercial buildings and is interfaced with air to water heat exchanger to heat domestic hot water. System has potential application in drying agricultural products such as cotton, lumber, corn, grains, and peanuts.

  6. Solar system for domestic hot water and space heating

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, W. [Arbeitsgemeinschaf Erneubare Energie, Gleisdorf (Austria)

    1997-12-31

    The solar thermal markets, different types of solar systems for hot water and space heating, the dimensioning and the components of solar heating systems, the properties of the systems are reviewed in this presentation

  7. Solar system for domestic hot water and space heating

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, W [Arbeitsgemeinschaf Erneubare Energie, Gleisdorf (Austria)

    1998-12-31

    The solar thermal markets, different types of solar systems for hot water and space heating, the dimensioning and the components of solar heating systems, the properties of the systems are reviewed in this presentation

  8. 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...

  9. Installation package for a solar heating and hot water system

    Science.gov (United States)

    1978-01-01

    Development and installation of two commercial solar heating and hot water systems are reported. The systems consist of the following subsystems: collector, storage, transport, hot water, auxiliary energy and controls. General guidelines are provided which may be utilized in development of detailed installation plans and specifications. In addition, operation, maintenance and repair of a solar heating and hot water system instructions are included.

  10. A novel solar hot plate for cooking

    Energy Technology Data Exchange (ETDEWEB)

    Rincon Mejia, Eduardo A; Osorio Jaramillo, Fidel A [Facultad de Ingenieria, UAEMex, Toluca, Edo. (Mexico)

    2000-07-01

    In Mexico and other developing countries, the use of firewood as combustible for cooking has contributed to deforestation and desertification of large zones. This is due to the lack of alternative combustibles for the poor inhabitants of the countryside and remote areas. In this paper, a new solar hot plate, intended for contributing to solve this problem, is presented. It can be used for cooking not only a great variety of prehispanic and traditional meals, like tortillas, fried meat and vegetables, but also hot cakes, bacon, eggs, steaks and fries. The hot plate solar cooker, called Tolocatzin, consists of a horizontal metallic plate, which is heated from both of its top and bottom surfaces by concentrated sun light from multicompound concentrator based on nonimaging optics, and built with nine ordinary plane glass-silvered, and two curved aluminum mirrors, so it can be manufactured easily in a small factory or at home. For an acceptance angle of 15 Celsius degrees, which allows the concentration of sun light without sun-tracking for about one hour, it can reach temperatures up to 240 Celsius degrees in a few minutes. This temperature is high enough for cooking almost all fried or grilled meals. The design was optimized using ray-trace procedures. The operational experience with early prototypes has shown that the Tolocatzin solar hot plate does an excellent cooking job and could really be massively used in sunny countries. [Spanish] En Mexico y otros paises en desarrollo, el uso de la madera como combustible para cocinar ha contribuido a la deforestacion y desertificacion de grandes zonas. Esto es debido a la falta de combustibles alternativos por parte de los habitantes pobres del campo y de areas remotas. En este articulo se presenta una nueva placa solar que tiene el proposito de contribuir a resolver este problema. Puede ser usada para cocinar no solamente una gran variedad de comidas prehispanicas y tradicionales, como tortillas, carne frita y verduras sino

  11. Solar wind flows associated with hot heavy ions

    International Nuclear Information System (INIS)

    Fenimore, E.E.

    1980-05-01

    Solar wind heavy ion spectra measured with the Vela instrumentation have been studied with the goal of determining the solar origins of various solar wind structures which contain anomalously high ionization states. Since the ionization states freeze-in close to the sun they are good indicators of the plasma conditions in the low and intermediate corona. Heavy ion spectra from three different periods throughout the solar cycle have been analyzed. These data are consistent with freezing-in temperatures ranging from approx. 1.5 x 10 6 K to higher than 9 x 10 6 . The spectra indicating hot coronal conditions occur in roughly 1/7 of all measurements and almost exclusively in postshock flows (PSFs), nonshock related helium abundance enhancements (HAEs), or noncompressive density enhancements (NCDEs). The PSFs and HAEs are both probably interplanetary manifestations of solar flares. The observation of several flare-related HAEs which were not preceded by an interplanetary shock suggests that the flare-heated plasma can evolve into the solar wind without producing a noticeable shock at 1 AU. The NCDEs with hot heavy ions differ from the PSF-HAEs in several ways implying that they evolve from events or places with lower temperatures and less energy than those associated with the flares, but with higher temperatures and densities than the quiet corona. Active regions, coronal mass ejections, and equatorial streamers are possible sources for the NCDEs with spectra indicating hot coronal conditions. These events owe their enhanced densities to coronal processes as opposed to interplanetary dynamical processes. Models of the solar wind expansion demonstrate how some NCDEs can have extreme, nonequilibrium ionization distributions

  12. Economics of residential solar hot water heating systems in Malaysia

    International Nuclear Information System (INIS)

    Abdulmula, Ahmed Mohamed Omer; Sopian, Kamaruzzaman; Haj Othman, Mohd Yosof

    2006-01-01

    Malaysia has favorable climatic conditions for the development of solar energy due to the abundant sunshine and is considered good for harnessing energy from the sun. This is because solar hot water can represent the large energy consumer in Malaysian households but, because of the high initial cost of Solar Water Heating Systems (SWHSs) and easily to install and relatively inexpensive to purchase electric water heaters, many Malyaysian families are still using Electric Water Heaters to hot their water needs. This paper is presented the comparing of techno-economic feasibility of some models of SWHS from Malaysian's market with the Electric Water Heaters )EWH) by study the annual cost of operation for both systems. The result shows that the annual cost of the electrical water heater becomes greater than than the annual cost of the SWHS for all models in long-team run so it is advantageous for the family to use the solar water heater, at least after 4 years. In addition with installation SWHS the families can get long-term economical benefits, environment friendly and also can doing its part to reduce this country's dependence on foreign oil that is price increase day after day.(Author)

  13. Domestic hot water and solar energy in Ireland

    Energy Technology Data Exchange (ETDEWEB)

    Hand, F; Asare, B; Haslett, J

    1977-01-01

    Two systems are discussed which involve the use of solar energy to supply domestic hot-water requirements and their usefulness in Ireland is examined. The systems are evaluated for thermal performance and cost-effectiveness by the use of a computer simulation model of a system involving a typical commercially available solar panel. It is shown that such systems may be economically justified when compared with electricity, but only if the water supply is directly heated by solar panels and only if the installed cost of such panels is low. Further, it appears that the system performance is relatively insensitive to the panel orientation and consequently that retro-fit installations on existing houses are unlikely to cause difficulties.

  14. Numerical Simulation of a Solar Domestic Hot Water System

    International Nuclear Information System (INIS)

    Mongibello, L; Graditi, G; Bianco, N; Di Somma, M; Naso, V

    2014-01-01

    An innovative transient numerical model is presented for the simulation of a solar Domestic Hot Water (DHW) system. The solar collectors have been simulated by using a zerodimensional analytical model. The temperature distributions in the heat transfer fluid and in the water inside the tank have been evaluated by one-dimensional models. The reversion elimination algorithm has been used to include the effects of natural convection among the water layers at different heights in the tank on the thermal stratification. A finite difference implicit scheme has been implemented to solve the energy conservation equation in the coil heat exchanger, and the energy conservation equation in the tank has been solved by using the finite difference Euler implicit scheme. Energy conservation equations for the solar DHW components models have been coupled by means of a home-made implicit algorithm. Results of the simulation performed using as input data the experimental values of the ambient temperature and the solar irradiance in a summer day are presented and discussed

  15. Numerical Simulation of a Solar Domestic Hot Water System

    Science.gov (United States)

    Mongibello, L.; Bianco, N.; Di Somma, M.; Graditi, G.; Naso, V.

    2014-11-01

    An innovative transient numerical model is presented for the simulation of a solar Domestic Hot Water (DHW) system. The solar collectors have been simulated by using a zerodimensional analytical model. The temperature distributions in the heat transfer fluid and in the water inside the tank have been evaluated by one-dimensional models. The reversion elimination algorithm has been used to include the effects of natural convection among the water layers at different heights in the tank on the thermal stratification. A finite difference implicit scheme has been implemented to solve the energy conservation equation in the coil heat exchanger, and the energy conservation equation in the tank has been solved by using the finite difference Euler implicit scheme. Energy conservation equations for the solar DHW components models have been coupled by means of a home-made implicit algorithm. Results of the simulation performed using as input data the experimental values of the ambient temperature and the solar irradiance in a summer day are presented and discussed.

  16. Prototype solar heating and cooling systems including potable hot water

    Science.gov (United States)

    1978-01-01

    Progress is reviewed in the development, delivery, and support of two prototype solar heating and cooling systems including potable hot water. The system consisted of the following subsystems: collector, auxiliary heating, potable hot water, storage, control, transport, and government-furnished site data acquisition.

  17. Ayres' bifurcated solar model

    International Nuclear Information System (INIS)

    Kalkofen, W.

    1985-01-01

    The assumptions of Ayres' model of the upper solar atmosphere are examined. It is found that the bistable character of his model is postulated - through the assumptions concerning the opacity sources and the effect of mechanical waves, which are allowed to destroy the CO molecules but not to heat the gas. The neglect of cooling by metal lines is based on their reduced local cooling rate, but it ignores the increased depth over which this cooling occurs. Thus, the bifurcated model of the upper solar atmosphere consists of two models, one cold at the temperature minimum, with a kinetic temperature of 2900 K, and the other hot, with a temperature of 4900 K. 8 references

  18. Preliminary design package for solar heating and hot water system

    Science.gov (United States)

    1976-01-01

    Two prototype solar heating and hot water systems for use in single-family dwellings or commercial buildings were designed. Subsystems included are: collector, storage, transport, hot water, auxiliary energy, and government-furnished site data acquisition. The systems are designed for Yosemite, California, and Pueblo, Colorado. The necessary information to evaluate the preliminary design for these solar heating and hot water systems is presented. Included are a proposed instrumentation plan, a training program, hazard analysis, preliminary design drawings, and other information about the design of the system.

  19. Experimental study of multipurpose solar hot box at Freiburg, Germany

    Energy Technology Data Exchange (ETDEWEB)

    Nandwani, S.S. [Iowa State University, Ames (United States). International Inst. of Theoretical and Applied Physics; Steinhart, J.; Henning, H.M.; Rommel, M.; Wittwer, V. [Fraunhofer-Institut fuer Solare Energiesysteme (ISE), Freiburg im Breisgau (Germany)

    1997-12-31

    With the aim to test an compare some properties of materials and common geometries that are used for designing solar cookers, water heaters, etc. we have made a solar hot box with two similar compartments. In the present study this hot box has been used for, (a) comparing the behavior of a metallic slab filled with a phase change material for short term heat storage, with a conventional absorbing sheet, (b) the use of a selectively coated, as compared to a normal black painted, cooking pot, and (c) for finding the overall heat loss coefficient and thermal capacity of the box. Experiments with the solar hot box will yield valuable information on solar systems that are to be constructed. Besides its use for research this multi-purpose device has been used both to pasteurize up to 14-16 l of water and for cooking. (author)

  20. Optimum hot water temperature for absorption solar cooling

    Energy Technology Data Exchange (ETDEWEB)

    Lecuona, A.; Ventas, R.; Venegas, M.; Salgado, R. [Dpto. Ingenieria Termica y de Fluidos, Universidad Carlos III de Madrid, Avda. Universidad 30, 28911 Leganes, Madrid (Spain); Zacarias, A. [ESIME UPA, IPN, Av. de las Granjas 682, Col. Santa Catarina, 02550, D.F. Mexico (Mexico)

    2009-10-15

    The hot water temperature that maximizes the overall instantaneous efficiency of a solar cooling facility is determined. A modified characteristic equation model is used and applied to single-effect lithium bromide-water absorption chillers. This model is based on the characteristic temperature difference and serves to empirically calculate the performance of real chillers. This paper provides an explicit equation for the optimum temperature of vapor generation, in terms of only the external temperatures of the chiller. The additional data required are the four performance parameters of the chiller and essentially a modified stagnation temperature from the detailed model of the thermal collector operation. This paper presents and discusses the results for small capacity machines for air conditioning of homes and small buildings. The discussion highlights the influence of the relevant parameters. (author)

  1. Anomalous energy transport in hot plasmas: solar corona and Tokamak

    International Nuclear Information System (INIS)

    Beaufume, P.

    1992-04-01

    Anomalous energy transport is studied in two hot plasmas and appears to be associated with a heating of the solar corona and with a plasma deconfining process in tokamaks. The magnetic structure is shown to play a fundamental role in this phenomenon through small scale instabilities which are modelized by means of a nonlinear dynamical system: the Beasts' Model. Four behavior classes are found for this system, which are automatically classified in the parameter space thanks to a neural network. We use a compilation of experimental results relative to the solar corona to discuss current-based heating processes. We find that a simple Joule effect cannot provide the required heating rates, and therefore propose a dimensional model involving a resistive reconnective instability which leads to an efficient and discontinuous heating mechanism. Results are in good agreement with the observations. We give an analytical expression for a diffusion coefficient in tokamaks when magnetic turbulence is perturbing the topology, which we validate thanks to the standard mapping. A realistic version of the Beasts' Model allows to test a candidate to anomalous transport: the thermal filamentation instability

  2. Energy efficiency of a solar domestic hot water system

    Science.gov (United States)

    Zukowski, Miroslaw

    2017-11-01

    The solar domestic hot water (SDHW) system located on the campus of Bialystok University of Technology is the object of the research described in the current paper. The solar thermal system is composed of 35 flat plate collectors, 21 evacuated tube collectors and eight hot water tanks with the capacity of 1 m3 of each. Solar facility is equipped with hardware for automatic data collection. Additionally, the weather station located on the roof of the building provides measurements of basic parameters of ambient air and solar radiation. The main objective of Regional Operational Program was the assessment of the effectiveness of this solar energy technology in the climatic conditions of the north-eastern Poland. Energy efficiency of SDHW system was defined in this research as the ratio between the useful heat energy supplied to the domestic hot water system and solar energy incident on the surface of solar panels. Heat loss from water storage tanks, and from the pipe network to the surrounding air, as well as the electrical energy consumed by the pumps have been included in the calculations. The paper presents the detailed results and conclusions obtained from this energy analysis.

  3. Preliminary design package for solar hot water system

    Energy Technology Data Exchange (ETDEWEB)

    Fogle, Val; Aspinwall, David B.

    1977-12-01

    The information necessary to evaluate the preliminary design of the Solar Engineering and Manufacturing Company's (SEMCO) solar hot water system is presented. This package includes technical information, schematics, drawings and brochures. This system, being developed by SEMCO, consists of the following subsystems: collector, storage, transport, control, auxiliary energy, and Government-furnished site data acquisition. The two units being manufactured will be installed at Loxahatchee, Florida, and Macon, Georgia.

  4. Smart solar tanks for small solar domestic hot water systems

    DEFF Research Database (Denmark)

    Furbo, Simon; Andersen, Elsa; Knudsen, Søren

    2005-01-01

    Investigation of small SDHW systems based on smart solar tanks are presented. The domestic water in a smart solar tank can be heated both by solar collectors and by means of an auxiliary energy supply system. The auxiliary energy supply system – in this study electric heating elements – heats up...... systems, based on differently designed smart solar tanks and a traditional SDHW system were investigated by means of laboratory experiments and theoretical calculations. The investigations showed that the yearly thermal performance of SDHW systems with smart solar tanks is 5-35% higher than the thermal...... performance of traditional SDHW systems. Estimates indicate that the performance/cost ratio can be improved by up to 25% by using a smart solar tank instead of a traditional tank when the backup energy system is electric heating elements. Further, smart solar tanks are suitable for unknown, variable, large...

  5. Entrance Effects in Solar Hot Water Stores

    DEFF Research Database (Denmark)

    Shah, Louise Jivan; Furbo, Simon

    2003-01-01

    A theoretical and experimental analysis of water jets entering a solar storage tank is performed. CFD calculations of three inlet designs with different inlet flow rates were carried out to illustrate the varying behaviour of the thermal conditions in a solar store. The results showed the impact ...... in an analysis using the first and second law of thermodynamics. The results showed how the entropy changes and the exergy changes in the storage during the draw-offs influenced by the Richardson number, the volume draw-off and the initial tank conditions....

  6. Installation package for a domestic solar heating and hot water system

    Science.gov (United States)

    1978-01-01

    The installation of two prototype solar heating and hot water systems is described. The systems consists of the following subsystems: solar collector, storage, control, transport, and auxiliary energy.

  7. Preliminary design package for solar heating and hot water system

    Science.gov (United States)

    1977-01-01

    The preliminary design review on the development of a multi-family solar heating and domestic hot water prototype system is presented. The report contains the necessary information to evaluate the system. The system consists of the following subsystems: collector, storage, transport, control and Government-furnished site data acquisition.

  8. Solar Hot Water Heating by Natural Convection.

    Science.gov (United States)

    Noble, Richard D.

    1983-01-01

    Presents an undergraduate laboratory experiment in which a solar collector is used to heat water for domestic use. The working fluid is moved by natural convection so no pumps are required. Experimental apparatus is simple in design and operation so that data can be collected quickly and easily. (Author/JN)

  9. Solar heating and hot water system installed at office building, One Solar Place, Dallas, Texas

    Science.gov (United States)

    1980-01-01

    A solar heating on cooling system is described which is designed to provide 87 percent of the space heating needs, 100 percent of the potable hot water needs and is sized for future absorption cooling. The collection subsystem consists of 28 solargenics, series 76, flat plate collectors with a total area of 1,596 square feet. The solar loop circulates an ethylene glyco water solution through the collectors into a hot water system exchanger. The water storage subsystem consists of a heat exchanger, two 2,300 gallon concrete hot water storage tanks with built in heat exchangers and a back-up electric boiler. The domestic hot water subsystem sends hot water to the 10,200 square feet floor area office building hot water water fixtures. The building cold water system provides make up to the solar loop, the heating loop, and the hot water concrete storage tanks. The design, construction, cost analysis, operation and maintenance of the solar system are described.

  10. Solar Hot Water System Matter in Turkey (Mersin Case

    Directory of Open Access Journals (Sweden)

    Müjgan ŞEREFHANOĞLU SÖZEN

    2010-01-01

    Full Text Available When the effects of sustainability on the construction sector have been taken into consideration, solar active systems on buildings emerge as an important design issue in the context of renewal energy usage. Solar hot water systems such as those widely used in Turkey are inefficient and have a negative effect on a building’s aesthetic and the urban view in general because of the poor quality of installation. Natural circulated open loop systems are commonly used, particularly in the south of Turkey, as they are highly economical and require no regulation to install. Solar hot water systems tend to be clustered together on the roofs, causing visual pollution, and this situation arises largely because are not considered part of the architectural design. It is therefore important to consider the negative effects of such systems in the form of treatment studies. This study aims to determine the positive effects that will be gained by the renovation of solar hot water systems in Mersin, a city in the southern region of Turkey.

  11. Models of hot stellar systems

    International Nuclear Information System (INIS)

    Van Albada, T.S.

    1986-01-01

    Elliptical galaxies consist almost entirely of stars. Sites of recent star formation are rare, and most stars are believed to be several billion years old, perhaps as old as the Universe itself (--10/sup 10/ yrs). Stellar motions in ellipticals show a modest amount of circulation about the center of the system, but most support against the force of gravity is provided by random motions; for this reason ellipticals are called 'hot' stellar systems. Spiral galaxies usually also contain an appreciable amount of gas (--10%, mainly atomic hydrogen) and new stars are continually being formed out of this gas, especially in the spiral arms. In contrast to ellipticals, support against gravity in spiral galaxies comes almost entirely from rotation; random motions of the stars with respect to rotation are small. Consequently, spiral galaxies are called 'cold' stellar systems. Other than in hot systems, in cold systems the collective response of stars to variations in the force field is an essential part of the dynamics. The present overview is limited to mathematical models of hot systems. Computational methods are also discussed

  12. Solar Drying in Hot and Dry Climate of Jaipur

    OpenAIRE

    Parikh, Darshit; Agrawal, G. D.

    2016-01-01

    Objective of the present study was to design, develop and to carry out detail experimentation and then analyze solar cabinet dryer. For these various types of solar dryer, their principles and design methods, modeling, drying temperature, efficiency, utilization of dryer and payback period were reviewed. In the present study, solar cabinet dryer is constructed at Mechanical Engineering Department, M.N.I.T, Jaipur, latitude (26.01° N). The measurement of solar intensity, temperatures, relative...

  13. Solar heating and hot water system installed at Listerhill, Alabama

    Science.gov (United States)

    1978-01-01

    The Solar system was installed into a new building and was designed to provide 79% of the estimated annual space heating load and 59% of the estimated annual potable hot water requirement. The collectors are flat plate, liquid manufactured by Reynolds Metals Company and cover a total area of 2344 square feet. The storage medium is water inhibited with NALCO 2755 and the container is an underground, unpressurized steel tank with a capacity of 5000 gallons. This report describes in considerable detail the solar heating facility and contains detailed drawings of the completed system.

  14. Application of solar energy to the supply of hot water for textile dyeing. Final report, CDRL/PA 10

    Energy Technology Data Exchange (ETDEWEB)

    None

    1977-09-01

    The design plan for a solar process hot water system for a textile dye beck at Riegel Textile Corporation's LaFrance, South Carolina, facilities is presented. The solar system consists of 396 GE model TC 100 evacuated tube collector modules arranged in a ground mounted array with a total collector area of 6680 square feet. The system includes an 8000-gallon hot water storage tank. Systems analyses, specification sheets, performance data, and an economic evaluation of the proposed system are presented. (WHK)

  15. Drying hot red pepper using solar tunnel drier

    International Nuclear Information System (INIS)

    Hossain, M.A; Bala, B.K.

    2006-01-01

    A solar tunnel drier was used to dry red hot pepper under the tropical weather conditions of Bangladesh in order to investigate its performance and the quality of the drier product. The drier comprises a plastic sheet-covered flat plate collector and a drying tunnel. The drier is arranged to supply hot air to the drying tunnel using two small fans powered by a 40 watt PV module. Fresh red pepper was water blanched before drying. In each drying batch in the solar tunnel drier, 20 kg of dried red pepper with 4 to 6% moisture content (wb) was obtained from 80 kg of fresh red pepper with initial moisture content of 73 to 75% (wb) in 20 to 22 hours of drying while it took 32 to 34 hours to bring down the moisture content of similar sample to 8 to 10% (wb) in sun drying methods. The pepper dried in the solar tunnel drier was completely protected from dust, dirt, rain, insects, birds, rodents and microorganisms and it was a quality-dried product in term of colour and pungency. The solar tunnel drier is recommended for drying of pepper as well as vegetables and fruits in developing countries especially in Bangladesh

  16. Solar hot-water generation and heating - Kombi-Kompakt+

    International Nuclear Information System (INIS)

    Haller, M.; Vogelsanger, P.

    2005-01-01

    This final report for the Swiss Federal Office of Energy (SFOE) describes new testing facilities at the Institute for Solar Technology in Rapperswil, Switzerland, that allow the testing of solar systems the whole year through. The systems tested feature the combined generation of heat for hot water storage vessels and heat for space heating. The test method used, the Concise Cycle Test (CCT) is described. The results of tests made on a large number of systems demonstrate that it is especially important to have a test system that allows the solar market to be protected from unsatisfactory systems. Good co-operation with manufactures is noted. As the test method includes tests with secondary energy sources such as oil or gas, certain problems in this area were discovered and corrected. Further tests are to be made with systems using biomass as a secondary source of heat

  17. Solar heating and domestic hot water system installed at Kansas City, Fire Stations, Kansas City, Missouri

    Science.gov (United States)

    1980-01-01

    The solar system was designed to provide 47 percent of the space heating, 8,800 square feet area and 75 percent of the domestic hot water (DHW) load. The solar system consists of 2,808 square feet of Solaron, model 2001, air, flat plate collector subsystem, a concrete box storage subsystem which contains 1,428 cubic feet of 0.5 inch diameter pebbles weighing 71.5 tons, a DHW preheat tank, blowers, pumps, heat exchangers, air ducting, controls and associated plumbing. Two 120 gallon electric DHW heaters supply domestic hot water which is preheated by the solar system. Auxiliary space heating is provided by three electric heat pumps with electric resistance heaters and four 30 kilowatt electric unit heaters. There are six modes of system operation.

  18. Solar heating and domestic hot water system installed at Kansas City, Fire Stations, Kansas City, Missouri

    Science.gov (United States)

    1980-07-01

    The solar system was designed to provide 47 percent of the space heating, 8,800 square feet area and 75 percent of the domestic hot water (DHW) load. The solar system consists of 2,808 square feet of Solaron, model 2001, air, flat plate collector subsystem, a concrete box storage subsystem which contains 1,428 cubic feet of 0.5 inch diameter pebbles weighing 71.5 tons, a DHW preheat tank, blowers, pumps, heat exchangers, air ducting, controls and associated plumbing. Two 120 gallon electric DHW heaters supply domestic hot water which is preheated by the solar system. Auxiliary space heating is provided by three electric heat pumps with electric resistance heaters and four 30 kilowatt electric unit heaters. There are six modes of system operation.

  19. System design package for SIMS prototype system 3, solar heating and domestic hot water

    Energy Technology Data Exchange (ETDEWEB)

    1978-11-01

    This report is a collation of documents and drawings that describe a prototype solar heating and hot water system using liquid flat plat collectors and a gas or electric furnace energy subsystem. The system was designed for installation into a single-family dwelling. The description, performance specification, subsystem drawings, verification plan/procedure, and hazard analysis of the system are packaged for evaluation of the system with information sufficient to assemble a similar system. The SIMS Prototype Heating and Hot Water System, Model Number 3 has been installed in a residence at Glendo State Park, Glendo, Wyoming.

  20. Center-to-Limb Variability of Hot Coronal EUV Emissions During Solar Flares

    Science.gov (United States)

    Thiemann, E. M. B.; Chamberlin, P. C.; Eparvier, F. G.; Epp, L.

    2018-02-01

    It is generally accepted that densities of quiet-Sun and active region plasma are sufficiently low to justify the optically thin approximation, and this is commonly used in the analysis of line emissions from plasma in the solar corona. However, the densities of solar flare loops are substantially higher, compromising the optically thin approximation. This study begins with a radiative transfer model that uses typical solar flare densities and geometries to show that hot coronal emission lines are not generally optically thin. Furthermore, the model demonstrates that the observed line intensity should exhibit center-to-limb variability (CTLV), with flares observed near the limb being dimmer than those occurring near disk center. The model predictions are validated with an analysis of over 200 flares observed by the EUV Variability Experiment (EVE) on the Solar Dynamics Observatory (SDO), which uses six lines, with peak formation temperatures between 8.9 and 15.8 MK, to show that limb flares are systematically dimmer than disk-center flares. The data are then used to show that the electron column density along the line of sight typically increases by 1.76 × 10^{19} cm^{-2} for limb flares over the disk-center flare value. It is shown that the CTLV of hot coronal emissions reduces the amount of ionizing radiation propagating into the solar system, and it changes the relative intensities of lines and bands commonly used for spectral analysis.

  1. Improved model for solar heating of buildings

    OpenAIRE

    Lie, Bernt

    2015-01-01

    A considerable future increase in the global energy use is expected, and the effects of energy conversion on the climate are already observed. Future energy conversion should thus be based on resources that have negligible climate effects; solar energy is perhaps the most important of such resources. The presented work builds on a previous complete model for solar heating of a house; here the aim to introduce ventilation heat recovery and improve on the hot water storage model. Ventilation he...

  2. Solar hot water systems application to the solar building test facility and the Tech House

    Science.gov (United States)

    Goble, R. L.; Jensen, R. N.; Basford, R. C.

    1976-01-01

    Projects which relate to the current national thrust toward demonstrating applied solar energy are discussed. The first project has as its primary objective the application of a system comprised of a flat plate collector field, an absorption air conditioning system, and a hot water heating system to satisfy most of the annual cooling and heating requirements of a large commercial office building. The other project addresses the application of solar collector technology to the heating and hot water requirements of a domestic residence. In this case, however, the solar system represents only one of several important technology items, the primary objective for the project being the application of space technology to the American home.

  3. Imitation experiment for water-treatment by heat of solar collector and hot pump

    International Nuclear Information System (INIS)

    Liao Yuanzong; Liu Shuqing; Pang Heding; Zhao Zhongxin; Zhang Biguang; Wang Xiping; Huo Guangqing

    1997-01-01

    The author presents an imitation experiment in which solar collector and hot pump are jointed for supplying heat to evaporate cleaned water and diffuse it into air. The effects of the temperature and the quantity of supplying air, and circumstance conditions on evaporation quantity are studied. The ratio of evaporating quantity to consuming energy, the efficiency of evaporation, average efficiency of solar collector and supplying heat coefficient of heat pump are measured. The experiment shows that this supplying heat model is practicable, economic and efficient for treating cleaned water

  4. Study on Thermal Performance Assessment of Solar Hot Water Systems in Malaysia

    Directory of Open Access Journals (Sweden)

    Sulaiman Shaharin Anwar

    2014-07-01

    Full Text Available Solar Hot Water Systems (SHWS are gaining popularity in Malaysia due to increasing cost of electricity and also awareness of environmental issues related to the use of fossil fuels. The introduction of solar hot water systems in Malaysia is an indication that it has potential market. However, there is a need for a proper methodology for rating the energy performance of these systems. The main objective of this study is to assess the thermal performance of several SHWS subject to four different locations in Malaysia using combined direct measurement and computer modelling using the TRNSYS simulation program. The results showed distinct differences in performance of the systems as a result of locations and manufacturers. The findings could be used further in developing an acceptable rating system for SHWS in Malaysia.

  5. Solar heating and hot water system installed at office building, One Solar Place, Dallas, Texas. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-01

    This document is the Final Report of the Solar Energy System Installed at the First Solar Heated Office Building, One Solar Place, Dallas, Texas. The Solar System was designed to provide 87 percent of the space heating needs, 100 percent of the potable hot water needs and is sized for future absorption cooling. The collection subsystem consists of 28 Solargenics, series 76, flat plate collectors with a total area of 1596 square feet. The solar loop circulates an ethylene glycol-water solution through the collectors into a hot water system heat exchanger. The hot water storage subsystem consists of a heat exchanger, two 2300 gallon concrete hot water storage tanks with built in heat exchangers and a back-up electric boiler. The domestic hot water subsystem sends hot water to the 10,200 square feet floor area office building hot water fixtures. The building cold water system provides make-up to the solar loop, the heating loop, and the hot water concrete storage tanks. The design, construction, cost analysis, operation and maintenance of the solar system are described. The system became operational July 11, 1979.

  6. Usage of solar aggregate stockpiles in the production of hot mix asphalt

    International Nuclear Information System (INIS)

    Androjić, Ivica; Kaluđer, Gordana

    2016-01-01

    Highlights: • Low energy storage mineral mixtures. • The impact of models thermal insulation on the temperature of aggregate. • Effect of periods with no solar radiation on the aggregate accumulated heat. • Low energy storage saves energy for preheating mineral mixtures. - Abstract: The production process of hot mix asphalt (HMA) requires a considerable demand for thermal energy which is fed into the process of drying and heating of mineral mixture. An overview of solar aggregate stockpiles designed in order to reduce energy consumption is given. Solar stockpiles were designed with the primary goal of achieving as much accumulation of thermal energy obtained from solar radiation as possible during the exposure period. Models of solar stockpiles were made with a constant volume capacity, variable thermal insulation thickness in the range of 2, 5 and 10 cm, and a glass ceiling surface to allow the realisation of high solar transmission into the interior of a stockpile. Temperature measurement of the mineral mixture deposited in the solar models and of those exposed to external environmental conditions was conducted during the period from May to November, 2015. The results achieved indicate to the facts that there comes to the constant growth in warmth of mineral mixtures in insulated stockpiles for the duration of their exposure to solar radiation, that an increase in thermal insulation thickness leads to the quadratic functional dependence between the referred thickness and mixture temperature and, ultimately, that there comes to the exponential loss of an accumulated thermal energy in insulated models in the period with no effect of solar radiation.

  7. A solar neutrino loophole: standard solar models

    Energy Technology Data Exchange (ETDEWEB)

    Rouse, C A [General Atomic Co., San Diego, Calif. (USA)

    1975-11-01

    The salient aspects of the existence theorem for a unique solution to a system of linear of nonlinear first-order, ordinary differential equations are given and applied to the equilibrium stellar structure equations. It is shown that values of pressure, temperature, mass and luminosity are needed at one point - and for the sun, the logical point is the solar radius. It is concluded that since standard solar model calculations use split boundary conditions, a solar neutrino loophole still remains: solar model calculations that seek to satisfy the necessary condition for a unique solution to the solar structure equations suggest a solar interior quite different from that deduced in standard models. This, in turn, suggests a theory of formation and solar evolution significantly different from the standard theory.

  8. Hot wire deposited hydrogenated amorphous silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Mahan, A.H.; Iwaniczko, E.; Nelson, B.P.; Reedy, R.C. Jr.; Crandall, R.S. [National Renewable Energy Lab., Golden, CO (United States)

    1996-05-01

    This paper details the results of a study in which low H content, high deposition rate hot wire (HW) deposited amorphous silicon (a-Si:H) has been incorporated into a substrate solar cell. The authors find that the treatment of the top surface of the HW i layer while it is being cooled from its high deposition temperature is crucial to device performance. They present data concerning these surface treatments, and correlate these treatments with Schottky device performance. The authors also present first generation HW n-i-p solar cell efficiency data, where a glow discharge (GD) {mu}c-Si(p) layer was added to complete the partial devices. No light trapping layer was used to increase the device Jsc. Their preliminary investigations have yielded efficiencies of up to 6.8% for a cell with a 4000 {Angstrom} thick HW i-layer, which degrade less than 10% after a 900 hour light soak. The authors suggest avenues for further improvement of their devices.

  9. Experimental Validation of a Domestic Stratified Hot Water Tank Model in Modelica for Annual Performance Assessment

    DEFF Research Database (Denmark)

    Carmo, Carolina; Dumont, Olivier; Nielsen, Mads Pagh

    2015-01-01

    The use of stratified hot water tanks in solar energy systems - including ORC systems - as well as heat pump systems is paramount for a better performance of these systems. However, the availability of effective and reliable models to predict the annual performance of stratified hot water tanks...

  10. Final report : testing and evaluation for solar hot water reliability.

    Energy Technology Data Exchange (ETDEWEB)

    Caudell, Thomas P. (University of New Mexico, Albuquerque, NM); He, Hongbo (University of New Mexico, Albuquerque, NM); Menicucci, David F. (Building Specialists, Inc., Albuquerque, NM); Mammoli, Andrea A. (University of New Mexico, Albuquerque, NM); Burch, Jay (National Renewable Energy Laboratory, Golden CO)

    2011-07-01

    Solar hot water (SHW) systems are being installed by the thousands. Tax credits and utility rebate programs are spurring this burgeoning market. However, the reliability of these systems is virtually unknown. Recent work by Sandia National Laboratories (SNL) has shown that few data exist to quantify the mean time to failure of these systems. However, there is keen interest in developing new techniques to measure SHW reliability, particularly among utilities that use ratepayer money to pay the rebates. This document reports on an effort to develop and test new, simplified techniques to directly measure the state of health of fielded SHW systems. One approach was developed by the National Renewable Energy Laboratory (NREL) and is based on the idea that the performance of the solar storage tank can reliably indicate the operational status of the SHW systems. Another approach, developed by the University of New Mexico (UNM), uses adaptive resonance theory, a type of neural network, to detect and predict failures. This method uses the same sensors that are normally used to control the SHW system. The NREL method uses two additional temperature sensors on the solar tank. The theories, development, application, and testing of both methods are described in the report. Testing was performed on the SHW Reliability Testbed at UNM, a highly instrumented SHW system developed jointly by SNL and UNM. The two methods were tested against a number of simulated failures. The results show that both methods show promise for inclusion in conventional SHW controllers, giving them advanced capability in detecting and predicting component failures.

  11. Reversible electron–hole separation in a hot carrier solar cell

    International Nuclear Information System (INIS)

    Limpert, S; Bremner, S; Linke, H

    2015-01-01

    Hot-carrier solar cells are envisioned to utilize energy filtering to extract power from photogenerated electron–hole pairs before they thermalize with the lattice, and thus potentially offer higher power conversion efficiency compared to conventional, single absorber solar cells. The efficiency of hot-carrier solar cells can be expected to strongly depend on the details of the energy filtering process, a relationship which to date has not been satisfactorily explored. Here, we establish the conditions under which electron–hole separation in hot-carrier solar cells can occur reversibly, that is, at maximum energy conversion efficiency. We thus focus our analysis on the internal operation of the hot-carrier solar cell itself, and in this work do not consider the photon-mediated coupling to the Sun. After deriving an expression for the voltage of a hot-carrier solar cell valid under conditions of both reversible and irreversible electrical operation, we identify separate contributions to the voltage from the thermoelectric effect and the photovoltaic effect. We find that, under specific conditions, the energy conversion efficiency of a hot-carrier solar cell can exceed the Carnot limit set by the intra-device temperature gradient alone, due to the additional contribution of the quasi-Fermi level splitting in the absorber. We also establish that the open-circuit voltage of a hot-carrier solar cell is not limited by the band gap of the absorber, due to the additional thermoelectric contribution to the voltage. Additionally, we find that a hot-carrier solar cell can be operated in reverse as a thermally driven solid-state light emitter. Our results help explore the fundamental limitations of hot-carrier solar cells, and provide a first step towards providing experimentalists with a guide to the optimal configuration of devices. (paper)

  12. Combined Active and Passive Solar Space Heating and Solar Hot Water Systems for an Elementary School in Boise, Idaho.

    Science.gov (United States)

    Smull, Neil A.; Armstrong, Gerald L.

    1979-01-01

    Amity Elementary School in Boise, Idaho, features a solar space heating and domestic hot water system along with an earth covering to accommodate the passive aspects of energy conservation. (Author/MLF)

  13. Seeded hot dark matter models with inflation

    Science.gov (United States)

    Gratsias, John; Scherrer, Robert J.; Steigman, Gary; Villumsen, Jens V.

    1993-01-01

    We examine massive neutrino (hot dark matter) models for large-scale structure in which the density perturbations are produced by randomly distributed relic seeds and by inflation. Power spectra, streaming velocities, and the Sachs-Wolfe quadrupole fluctuation are derived for this model. We find that the pure seeded hot dark matter model without inflation produces Sachs-Wolfe fluctuations far smaller than those seen by COBE. With the addition of inflationary perturbations, fluctuations consistent with COBE can be produced. The COBE results set the normalization of the inflationary component, which determines the large-scale (about 50/h Mpc) streaming velocities. The normalization of the seed power spectrum is a free parameter, which can be adjusted to obtain the desired fluctuations on small scales. The power spectra produced are very similar to those seen in mixed hot and cold dark matter models.

  14. Thermal analysis and performance optimization of a solar hot water plant with economic evaluation

    KAUST Repository

    Kim, Youngdeuk

    2012-05-01

    The main objective of this study is to optimize the long-term performance of an existing active-indirect solar hot water plant (SHWP), which supplies hot water at 65 °C for use in a flight kitchen, using a micro genetic algorithm in conjunction with a relatively detailed model of each component in the plant and solar radiation model based on the measured data. The performance of SHWP at Changi International Airport Services (CIASs), Singapore, is studied for better payback period using the monthly average hourly diffuse and beam radiations and ambient temperature data. The data input for solar radiation model is obtained from the Singapore Meteorological Service (SMS), and these data have been compared with long-term average data of NASA (surface meteorology and solar energy or SSE). The comparison shows a good agreement between the predicted and measured hourly-averaged, horizontal global radiation. The SHWP at CIAS, which comprises 1200m 2 of evacuated-tube collectors, 50m 3 water storage tanks and a gas-fired auxiliary boiler, is first analyzed using a baseline configuration, i.e., (i) the local solar insolation input, (ii) a coolant flow rate through the headers of collector based on ASHRAE standards, (iii) a thermal load demand pattern amounting to 100m 3/day, and (iv) the augmentation of water temperature by auxiliary when the supply temperature from solar tank drops below the set point. A comparison between the baseline configuration and the measured performance of CIAS plant gives reasonably good validation of the simulation code. Optimization is further carried out for the following parameters, namely; (i) total collector area of the plant, (ii) storage volume, and (iii) three daily thermal demands. These studies are performed for both the CIAS plant and a slightly modified plant where the hot water supply to the load is adjusted constant at times when the water temperature from tank may exceed the set temperature. It is found that the latter

  15. Thermal analysis and performance optimization of a solar hot water plant with economic evaluation

    KAUST Repository

    Kim, Youngdeuk; Thu, Kyaw; Bhatia, Hitasha Kaur; Bhatia, Charanjit Singh; Ng, K. C.

    2012-01-01

    The main objective of this study is to optimize the long-term performance of an existing active-indirect solar hot water plant (SHWP), which supplies hot water at 65 °C for use in a flight kitchen, using a micro genetic algorithm in conjunction with a relatively detailed model of each component in the plant and solar radiation model based on the measured data. The performance of SHWP at Changi International Airport Services (CIASs), Singapore, is studied for better payback period using the monthly average hourly diffuse and beam radiations and ambient temperature data. The data input for solar radiation model is obtained from the Singapore Meteorological Service (SMS), and these data have been compared with long-term average data of NASA (surface meteorology and solar energy or SSE). The comparison shows a good agreement between the predicted and measured hourly-averaged, horizontal global radiation. The SHWP at CIAS, which comprises 1200m 2 of evacuated-tube collectors, 50m 3 water storage tanks and a gas-fired auxiliary boiler, is first analyzed using a baseline configuration, i.e., (i) the local solar insolation input, (ii) a coolant flow rate through the headers of collector based on ASHRAE standards, (iii) a thermal load demand pattern amounting to 100m 3/day, and (iv) the augmentation of water temperature by auxiliary when the supply temperature from solar tank drops below the set point. A comparison between the baseline configuration and the measured performance of CIAS plant gives reasonably good validation of the simulation code. Optimization is further carried out for the following parameters, namely; (i) total collector area of the plant, (ii) storage volume, and (iii) three daily thermal demands. These studies are performed for both the CIAS plant and a slightly modified plant where the hot water supply to the load is adjusted constant at times when the water temperature from tank may exceed the set temperature. It is found that the latter

  16. Economic efficiency of solar hot water policy in New Zealand

    International Nuclear Information System (INIS)

    Gillingham, Kenneth

    2009-01-01

    New Zealand has recently followed the path of several other countries in promoting solar hot water (SHW) systems in the effort to reduce greenhouse gas emissions, yet the economic efficiency of large-scale policies to encourage SHW remains a pressing question for policymakers. This paper develops an economic framework to examine policies to promote SHW in New Zealand, including the current information, training, and subsidy policy. The economic framework points to environmental, energy security, and average-cost electricity retail pricing market failures as motivation for SHW policy, with the global climate change externality the most important of these. The results indicate that domestic SHW systems are close to being financially attractive from a consumer perspective, but a more substantial subsidy policy would be necessary for SHW to appeal to a wider audience. Such a policy is far more likely to have positive net benefits than a policy of mandating SHW on all homes or all new homes in New Zealand, and could be justified on economic efficiency grounds under reasonable assumptions. However, this result reverses under an economy-wide carbon trading system that internalizes the environmental externality.

  17. Design package for a complete residential solar space heating and hot water system

    Science.gov (United States)

    1978-01-01

    Information necessary to evaluate the design of a solar space heating and hot water system is reported. System performance specifications, the design data brochure, the system description, and other information pertaining to the design are included.

  18. Solar hot water system installed at Las Vegas, Nevada. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1981-01-01

    The solar hot water system installed at LaQuinta Motor Inn Inc., at Las Vegas, Nevada is described. The Inn is a three-story building with a flat roof for installation of the solar panels. The system consists of 1200 square feet of liquid flat plate collectors, a 2500 gallon insulated vertical steel storage tank, two heat exchangers and pumps and controls. The system was designed to supply approximately 74 percent of the total hot water load.

  19. Single-nanowire, low-bandgap hot carrier solar cells with tunable open-circuit voltage

    Science.gov (United States)

    Limpert, Steven; Burke, Adam; Chen, I.-Ju; Anttu, Nicklas; Lehmann, Sebastian; Fahlvik, Sofia; Bremner, Stephen; Conibeer, Gavin; Thelander, Claes; Pistol, Mats-Erik; Linke, Heiner

    2017-10-01

    Compared to traditional pn-junction photovoltaics, hot carrier solar cells offer potentially higher efficiency by extracting work from the kinetic energy of photogenerated ‘hot carriers’ before they cool to the lattice temperature. Hot carrier solar cells have been demonstrated in high-bandgap ferroelectric insulators and GaAs/AlGaAs heterostructures, but so far not in low-bandgap materials, where the potential efficiency gain is highest. Recently, a high open-circuit voltage was demonstrated in an illuminated wurtzite InAs nanowire with a low bandgap of 0.39 eV, and was interpreted in terms of a photothermoelectric effect. Here, we point out that this device is a hot carrier solar cell and discuss its performance in those terms. In the demonstrated devices, InP heterostructures are used as energy filters in order to thermoelectrically harvest the energy of hot electrons photogenerated in InAs absorber segments. The obtained photovoltage depends on the heterostructure design of the energy filter and is therefore tunable. By using a high-resistance, thermionic barrier, an open-circuit voltage is obtained that is in excess of the Shockley-Queisser limit. These results provide generalizable insight into how to realize high voltage hot carrier solar cells in low-bandgap materials, and therefore are a step towards the demonstration of higher efficiency hot carrier solar cells.

  20. Solar heating and hot water system installed at Arlington Raquetball Club, Arlington, Virginia

    Science.gov (United States)

    1981-01-01

    A solar space and water heating system is described. The solar energy system consists of 2,520 sq. ft. of flat plate solar collectors and a 4,000 gallon solar storage tank. The transfer medium in the forced closed loop is a nontoxic antifreeze solution (50 percent water, 50 percent propylene glycol). The service hot water system consists of a preheat coil (60 ft. of 1 1/4 in copper tubing) located in the upper third of the solar storage tank and a recirculation loop between the preheat coil and the existing electric water heaters. The space heating system consists of two separate water to air heat exchangers located in the ducts of the existing space heating/cooling systems. The heating water is supplied from the solar storage tank. Extracts from site files, specification references for solar modifications to existing building heating and hot water systems, and installation, operation and maintenance instructions are included.

  1. Motel solar-hot-water system with nonpressurized storage--Jacksonville, Florida

    Science.gov (United States)

    1981-01-01

    Modular roof-mounted copper-plated arrays collect solar energy; heated water drains from them into 1,000 gallon nonpressurized storage tank which supplies energy to existing pressurized motel hot water lines. System provides 65 percent of hot water demand. Report described systems parts and operation, maintenance, and performance and provides warranty information.

  2. Solar heating and hot water system installed at Shoney's Restaurant, North Little Rock, Arkansas

    Science.gov (United States)

    1980-01-01

    A solar heating system designed to supply a major portion of the space and water heating requirements for a restaurant is described. The restaurant has a floor space of approximately 4,650 square feet and requires approximate 1500 gallons of hot water daily. The solar energy system consists of 1,428 square feet of Chamberlain flat plate liquid collector subsystem, and a 1500 gallon storage subsystem circulating hot water producing 321 x 10 to the 6th power Btu/Yr (specified) building heating and hot water heating.

  3. Solar heating and domestic hot water system installed at North Dallas High School

    Science.gov (United States)

    1980-01-01

    The solar energy system located at the North Dallas High School, Dallas, Texas is discussed. The system is designed as a retrofit in a three story with basement, concrete frame high school building. Extracts from the site files, specification references for solar modification to existing building heating and domestic hot water systems, drawings, installation, operation and maintenance instructions are included.

  4. Prediction and experimental validation of stagnation temperature attained by a solar cooker of hot box type

    Energy Technology Data Exchange (ETDEWEB)

    Narasimha Rao, A. V; Srikrishna, D. V. N [Warangal (India)

    2000-07-01

    A hot box type solar cooker, having double glass covers and a plane mirror reflector, is tested for stagnation temperature. A computer code is developed based on the analytical model proposed by Vaishya et. al. The global and beam components of solar radiation measured at Warangal are made use to predict the stagnation temperature of the cooker. The observed values of stagnation temperature at Warangal are compared with those of predicted values. A good agreement of the measured and observed values of the stagnation temperature is observed during the afternoon period. The lag in the observed values during the forenoon may be due to thermal inertia of the cooker. [Spanish] Se probo una estufa solar de tipo caja caliente con cubiertas dobles de vidrio y un espejo reflector plano para medir la temperatura de estancamiento. Se desarrollo un codigo de computacion basado en el modelo analitico propuesto por Vaishya et. al. Los componentes de la radiacion solar globales y de rayo medidos en Warangal se usan para predecir la temperatura de estancamiento de la estufa. Los valores observados de la temperatura de estancamiento en Warangal se comparan con los valores predichos. Se aprecia una buena concidencia de los valores medidos y observados de la temperatura de estancamiento durante el periodo de la tarde. El retraso de los valores observados durante la manana puede ser debido a la inercia termica de la estufa.

  5. Building America Case Study: Addressing Multifamily Piping Losses with Solar Hot Water, Davis, California

    Energy Technology Data Exchange (ETDEWEB)

    2016-12-01

    Solar thermal water heating is most cost effective when applied to multifamily buildings and some states offer incentives or other inducements to install them. However, typical solar water heating designs do not allow the solar generated heat to be applied to recirculation losses, only to reduce the amount of gas or electric energy needed for hot water that is delivered to the fixtures. For good reasons, hot water that is recirculated through the building is returned to the water heater, not to the solar storage tank. The project described in this report investigated the effectiveness of using automatic valves to divert water that is normally returned through the recirculation piping to the gas or electric water heater instead to the solar storage tank. The valves can be controlled so that the flow is only diverted when the returning water is cooler than the water in the solar storage tank.

  6. Using Solar Hot Water to Address Piping Heat Losses in Multifamily Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Springer, David [Alliance for Residential Building Innovation, Davis, CA (United States); Seitzler, Matt [Alliance for Residential Building Innovation, Davis, CA (United States); Backman, Christine [Alliance for Residential Building Innovation, Davis, CA (United States); Weitzel, Elizabeth [Alliance for Residential Building Innovation, Davis, CA (United States)

    2015-10-01

    Solar thermal water heating is most cost effective when applied to multifamily buildings and some states offer incentives or other inducements to install them. However, typical solar water heating designs do not allow the solar generated heat to be applied to recirculation losses, only to reduce the amount of gas or electric energy needed for hot water that is delivered to the fixtures. For good reasons, hot water that is recirculated through the building is returned to the water heater, not to the solar storage tank. The project described in this report investigated the effectiveness of using automatic valves to divert water that is normally returned through the recirculation piping to the gas or electric water heater instead to the solar storage tank. The valves can be controlled so that the flow is only diverted when the returning water is cooler than the water in the solar storage tank.

  7. Solar Energy for Domestic Hot Water: Case Studies in Sisimiut 1999-2005

    DEFF Research Database (Denmark)

    Reimann, Gregers Peter

    2005-01-01

    Two pioneer solar domestic hot water systems were installed at Bygge- og Anlægsskolen in Sisimiut in 1999 and 2000. Detailed measurements of energy flows and solar radiation incl. snow reflectance has been undertaken for both plants. Since August 2004 data logging of the measurements was made...... available online on the website www.arcticsolar.com. Measurements show that solar plant 1 and 2 cover 22% and 23%, respectively, of the energy spent for domestic hot water heating. This paper summarises the findings from the past 5 years....

  8. Quantitative experimental assessment of hot carrier-enhanced solar cells at room temperature

    Science.gov (United States)

    Nguyen, Dac-Trung; Lombez, Laurent; Gibelli, François; Boyer-Richard, Soline; Le Corre, Alain; Durand, Olivier; Guillemoles, Jean-François

    2018-03-01

    In common photovoltaic devices, the part of the incident energy above the absorption threshold quickly ends up as heat, which limits their maximum achievable efficiency to far below the thermodynamic limit for solar energy conversion. Conversely, the conversion of the excess kinetic energy of the photogenerated carriers into additional free energy would be sufficient to approach the thermodynamic limit. This is the principle of hot carrier devices. Unfortunately, such device operation in conditions relevant for utilization has never been evidenced. Here, we show that the quantitative thermodynamic study of the hot carrier population, with luminance measurements, allows us to discuss the hot carrier contribution to the solar cell performance. We demonstrate that the voltage and current can be enhanced in a semiconductor heterostructure due to the presence of the hot carrier population in a single InGaAsP quantum well at room temperature. These experimental results substantiate the potential of increasing photovoltaic performances in the hot carrier regime.

  9. Identification and assessment of environmental benefits from solar hot water production

    International Nuclear Information System (INIS)

    Haralambopoulos, D.; Spilanis, I.

    1997-01-01

    The environmental benefits associated with the utilization of solar energy for hot water production are estimated in this work. The case of a particular country, Greece, and its electricity production system is employed to show the direct consequences of substituting electricity with solar energy for hot water production. The amount of conventional fuel saved, i.e. lignite and oil, is estimated, and the reduction in air pollution is calculated. This allows the calculation of reduction emission factors for solar hot water production to be undertaken. Data, with respect to the materials and the amount of energy necessary for the construction of the solar heaters, are also presented. These can serve as inputs to an energy-environment policy framework in order to lead to reduction of air pollutants like SO 2 , NO X and particulates, and the release of the greenhouse gas CO 2 into the atmosphere. (Author)

  10. Thermal solar energy. Collective domestic hot water installations

    International Nuclear Information System (INIS)

    Garnier, Cedric; Chauvet, Chrystele; Fourrier, Pascal

    2016-01-01

    This brochure, edited by ADEME, the French office for energy management and sustainable development, gives a basic outlook on the way to complete the installation of a collective domestic water solar heating system. After some recall of what is solar energy, the thermal solar technology and the energy savings it may induce, this document presents the main hydraulic configurations of a solar heating system with water storage, the dimensioning of a solar water heating system and its cost estimation, the installation and the commissioning of the system, the monitoring and maintenance operations

  11. Advantages using inlet stratification devices in solar domestic hot water storage tanks

    DEFF Research Database (Denmark)

    Dragsted, Janne; Furbo, Simon; Bava, Federico

    2017-01-01

    performances of two solar domestic hot water systems are presented. One system is a traditional high flow system with a heat exchanger spiral in the tank. The other system is a low flow system with an external heat exchanger and a newly developed inlet stratifier from EyeCular Technologies ApS installed......The thermal performance of a domestic hot water system is strongly affected by whether the storage tank is stratified or not. Thermal stratification can be built up in a solar storage tank if the heated water from the solar collectors enters the tank through an inlet stratifier.Measured thermal...... with the stratification device has a higher thermal performance compared to the system with the heat exchanger spiral inside the tank.The relative performance (defined as the ratio between the net utilized solar energy of the low flow system and the net utilized solar energy of the high flow system), is a function...

  12. Solar heating and hot water system installed at Saint Louis, Missouri

    Science.gov (United States)

    1980-01-01

    The solar heating and hot water system installed at the William Tao & Associates, Inc., office building in St. Louis, Missouri is described, including maintenance and construction problems, final drawings, system requirements, and manufacturer's component data. The solar system was designed to provide 50 percent of the hot water requirements and 45 percent of the space heating needs for a 900 sq ft office space and drafting room. The solar facility has 252 sq ft of glass tube concentrator collectors and a 1000 gallon steel storage tank buried below a concrete slab floor. Freeze protection is provided by a propylene glycol/water mixture in the collector loop. The collectors are roof mounted on a variable tilt array which is adjusted seasonally and is connected to the solar thermal storage tank by a tube-in-shell heat exchanger. Incoming city water is preheated through the solar energy thermal storage tank.

  13. HOT PLASMA FROM SOLAR ACTIVE-REGION CORES: CONSTRAINTS FROM THE HINODE X-RAY TELESCOPE

    Energy Technology Data Exchange (ETDEWEB)

    Schmelz, J. T. [USRA, 7178 Columbia Gateway Drive, Columbia, MD 21046 (United States); Christian, G. M.; Matheny, P. O., E-mail: jschmelz@usra.edu [Physics Department, University of Memphis, Memphis, TN 38152 (United States)

    2016-12-20

    Mechanisms invoked to heat the solar corona to millions of degrees kelvin involve either magnetic waves or magnetic reconnections. Turbulence in the convection zone produces MHD waves, which travel upward and dissipate. Photospheric motions continuously build up magnetic energy, which is released through magnetic reconnection. In this paper, we concentrate on hot non-flaring plasma with temperatures of 5 MK <  T  < 10 MK because it is one of the few observables for which wave and reconnection models make different predictions. Wave models predict no (or little) hot plasma, whereas reconnection models predict it, although in amounts that are challenging to detect with current instrumentation. We used data from the X-ray Telescope (XRT) and the Atmospheric Imaging Assembly (AIA). We requested a special XRT observing sequence, which cycled through the thickest XRT filter several times per hour so we could average these images and improve the signal-to-noise. We did differential emission measure (DEM) analysis using the time-averaged thick-filter data as well as all available channels from both the XRT and AIA for regions observed on 2014 December 11. Whereas our earlier work was only able to determine that plasma with a temperature greater than 5 MK was present , we are now able to find a well-constrained DEM distribution. We have therefore added a strong observational constraint that must be explained by any viable coronal heating model. Comparing state-of-the-art wave and reconnection model predictions, we can conclude that reconnection is heating the hot plasma in these active regions.

  14. Looking beyond installation: Why households struggle to make the most of solar hot water systems

    International Nuclear Information System (INIS)

    Gill, Nicholas; Osman, Peter; Head, Lesley; Voyer, Michelle; Harada, Theresa; Waitt, Gordon; Gibson, Chris

    2015-01-01

    This paper examines household responses to sustainability issues and adoption of energy saving technologies. Our example of solar hot water systems highlights the complexity and variability of responses to low-carbon technologies. While SHW systems have the potential to provide the majority of household hot water and to lower carbon emissions, little research has been done to investigate how SHW systems are integrated into everyday life. We draw on cultural understandings of the household to identify passive and active users of SHW systems and utilize a model that illustrates how technology use is dependent on inter-relations between cultural norms, systems of provision, the material elements of homes, and practice. A key finding is that households can be ill-prepared to make the most of their SHW systems and lack post-installation support to do so. Thus, informed and efficient use of SHW systems is hit and miss. Current policy is largely aimed at subsidizing purchase and installation on the assumption that this is sufficient for emission reduction goals. Our analysis provides evidence to the contrary. Areas we highlight for policy and practice improvement are independent pre-purchase advice, installation quality, and practical guidance on system operation and interaction with patterns of hot water use. - Highlights: • We interview Australian households about their experience with SHW systems. • We identify active and passive users of SHW. Active users tend to be dissatisfied with their system. • Passive users tend to be satisfied but have relatively inefficient systems. • Householders struggle to integrate hot water use and system operation, compromising efficiency. • Policy should encompass pre and post-installation support as much as incentives to install.

  15. Development of domestic hot water systems in Costa Rica from solar energy

    International Nuclear Information System (INIS)

    Lizana-Moreno, Fernando

    2015-01-01

    A software tool is developed to implement the solar domestic hot water systems (DHW) in Costa Rica and to replace the electric water heating equipment. A database with information from the solar radiation is elaborated for different locations in Costa Rica. A manual of design DHW solar systems is realized for the country. An DHW solar system is designed for the type of average building the of country. A software is implemented to calculate the parameters and dimensions necessary for the solar installation of DHW, using the F-Chart method; in addition, the information of the mentioned database is included. A financial analysis is elaborated of the DHW solar systems in Costa Rica. The strategies are proposed for the implementation of DHW solar systems in Costa Rica [es

  16. Analysis of systems for hot water supply with solar energy utilization

    International Nuclear Information System (INIS)

    Zlateva, M.

    2001-01-01

    The results from the analysis of the hot water consumption of a group of hotels in the Black See resort Albena are presented. Structural schemes of hot water solar systems with flat plate collectors have been synthesized. By the synthesis have been analyzed the type of the consumers, the operating period, the existing heating plants, the auxiliary energy source - electricity. The change of the solar fraction by different performance of the system have been investigated. A comparative analysis of the alternative solutions has been fulfilled. The most advantageous solution has been chosen on the basis of the evaluation of the pay-back period, the life cycle savings and the benefit-cost ratio. The effect of the changing economic characteristics on the economic efficiency have been investigated. The risk for the investments has been examined. It had been proved that for the conditions in Bulgarian Black See region the use of solar energy for hot water producing is economic reasonable. (author)

  17. Solar heating and hot water system installed at Cherry Hill, New Jersey

    Science.gov (United States)

    1979-01-01

    The solar heating and hot water system installed in existing buildings at the Cherry Hill Inn in Cherry Hill, New Jersey is described in detail. The system is expected to furnish 31.5% of the overall heating load and 29.8% of the hot water load. The collectors are liquid evacuated tube type. The storage system is an above ground insulated steel water tank with a capacity of 7,500 gallons.

  18. The Development of a Roof Integrated Solar Hot Water System

    Energy Technology Data Exchange (ETDEWEB)

    Menicucci, David F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Energy Infrastructure and DER Dept.; Moss, Timothy A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Solar Technologies Dept.; Palomino, G. Ernest [Salt River Project (SRP), Tempe, AZ (United States)

    2006-09-01

    The Salt River Project (SRP), in conjunction with Sandia National Laboratories (SNL) and Energy Laboratories, Inc. (ELI), collaborated to develop, test, and evaluate an advanced solar water-heating product for new homes. SRP and SNL collaborated under a Department of Energy Cooperative Research and Development Agreement (CRADA), with ELI as SRP's industry partner. The project has resulted in the design and development of the Roof Integrated Thermal Siphon (RITH) system, an innovative product that features complete roof integration, a storage tank in the back of the collector and below the roofline, easy installation by homebuilders, and a low installed cost. SRP's market research guided the design, and the laboratory tests conducted at SNL provided information used to refine the design of field test units and indicated that the RITH concept is viable. ELI provided design and construction expertise and is currently configured to manufacture the units. This final report for the project provides all of the pertinent and available materials connected to the project including market research studies, the design features and development of the system, and the testing and evaluation conducted at SNL and at a model home test site in Phoenix, Arizona.

  19. Hot-carrier solar cells using low-dimensional quantum structures

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Daiki; Kasamatsu, Naofumi; Harada, Yukihiro; Kita, Takashi [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan)

    2014-10-27

    We propose a high-conversion-efficiency solar cell (SC) utilizing the hot carrier (HC) population in an intermediate-band (IB) of a quantum dot superlattice (QDSL) structure. The bandgap of the host semiconductor in this device plays an important role as an energy-selective barrier for HCs in the QDSLs. According to theoretical calculation using the detailed balance model with an air mass 1.5 spectrum, the optimum IB energy is determined by a trade-off relation between the number of HCs with energy exceeding the conduction-band edge and the number of photons absorbed by the valence band−IB transition. Utilizing experimental data of HC temperature in InAs/GaAs QDSLs, the maximum conversion efficiency under maximum concentration (45 900 suns) has been demonstrated to increase by 12.6% as compared with that for a single-junction GaAs SC.

  20. Energy behavior of solar hot water systems under different conditions

    International Nuclear Information System (INIS)

    Fuentes Lombá, Osmanys; Torres Ten, Alonso; Arzuaga Machado, Yusnel; Hernández, Massipe J. Raúl; Cueva Gonzales, Wagner

    2017-01-01

    By means of numerical simulations in TRNSYS v14 the influence of the solar absorption area of a system for heating water with solar energy, composed by a flat solar collector and a tank thermo-accumulator, on its energy efficiency. For the study, the solar collectors EDWARDS, ISOFOTÓN 1, ISOFOTÓN 2, MADE, ROLDAN and IBERSOLAR of absorption area 2, 1,9, 1,88, 2, 1,9 and 2,3 m2 respectively were chosen. For each collector, the energy performance was simulated for one year, setting 200 L for the accumulation volume and 50 °C for the intake temperature. Despite the different characteristics of each collector, their behavior is quite similar showing a very mature technology. (author)

  1. Modelling solar-like oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Eggenberger, P; Miglio, A [Institut d' Astrophysique et de Geophysique de l' Universite de Liege, 17 Allee du 6 Aout, B-4000 Liege (Belgium); Carrier, F [Institute of Astronomy, University of Leuven, Celestijnenlaan 200 D, B-3001 Leuven (Belgium); Mathis, S [CEA/DSM/DAPNIA/Service d' Astrophysique, CEA/Saclay, AIM-Unite Mixte de Recherche CEA-CNRS-Universite Paris VII, UMR 7158, 91191 Gif-sur-Yvette Cedex (France)], E-mail: eggenberger@Qastro.ulg.ac.be

    2008-10-15

    The computation of models of stars for which solar-like oscillations have been observed is discussed. After a brief intoduction on the observations of solar-like oscillations, the modelling of isolated stars and of stars belonging to a binary system is presented with specific examples of recent theoretical calibrations. Finally the input physics introduced in stellar evolution codes for the computation of solar-type stars is discussed with a peculiar emphasis on the modelling of rotation for these stars.

  2. Solar hot water system installed at Quality Inn, Key West, Florida

    Science.gov (United States)

    1980-04-01

    The solar energy hot water system installed in the Quality Inn, Key West, Florida, which consists of four buildings is described. Three buildings are low-rise, two-story buildings containing 100 rooms. The fourth is a four-story building with 48 rooms. The solar system was designed to provide approximately 50 percent of the energy required for the domestic hot water system. The solar system consists of approximately 1400 square feet of flat plate collector, two 500 gallon storage tanks, a circulating pump, and a controller. Operation of the system was begun in April 1978, and has continued to date with only three minor interruptions for pump repair. In the first year of operation, it was determined that the use of the solar facility resulted in forty percent fuel savings.

  3. Simulation of the interaction of a solar domestic hot water tank system with a compact plate heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Nizami, D.J.; Lightstone, M.F. [McMaster Univ., Hamilton, ON (Canada). Dept. of Mechanical Engineering; Harrison, S.; Cruickshank, C. [Queen' s Univ., Kingston, ON (Canada). Dept. of Mechanical and Materials Engineering

    2008-08-15

    An external natural convection heat exchanger (NCHE) was used as an alternative to forced convection for transferring energy from solar collector loops to a hot water storage tank. A computational fluid dynamics (CFD) program was used to predict interactions between the natural convection-driven side-arm heat exchanger and a hot water storage tank. A solar domestic hot water tank with a vertical compact plate natural convection heat exchanger was modelled. In addition, the heat exchanger was modelled as a section of pipe with high flow resistance and a volumetric energy source. Transient analyses were conducted and the CFD model was then compared with data obtained from laboratory experiments. Simulations were conducted on the fluid domain in order to investigate the influence of the flow on the thermal stratification in the tank, the heat transfer inside the tank, and the natural convection in the tank loop. Buoyancy for an incompressible fluid with constant fluid properties was modelled using a Boussinesq approximation. Temperature distributions were measured as a function of time. Results of the study indicated that assuming a constant thermal expansion coefficient in evaluation buoyancy forces for a wide range of operating temperatures did not result in accurate predictions. Future studies will model natural convection with a full buoyancy model. 11 refs., 2 tabs., 5 figs.

  4. Heat Transfer Model for Hot Air Balloons

    OpenAIRE

    Lladó Gambín, Adriana

    2016-01-01

    A heat transfer model and analysis for hot air balloons is presented in this work, backed with a flow simulation using SolidWorks. The objective is to understand the major heat losses in the balloon and to identify the parameters that affect most its flight performance. Results show that more than 70% of the heat losses are due to the emitted radiation from the balloon envelope and that convection losses represent around 20% of the total. A simulated heating source is also included in the mod...

  5. Study of emission process in hot, optically thin plasma: application to solar active regions

    International Nuclear Information System (INIS)

    Steenman-Clark, Lois.

    1983-06-01

    Analysis of soft X-ray got in hot and weak density plasmas, such as those in TOKAMAKS and in solar flares, needs a detailed knowledge of emission processes. In this work are presented spectroscopic diagnostics which can be deduced from such spectra analysis and results are applied to magnesium solar spectrum analysis. An important improvement is brought to collisional calculation corresponding to forbidden line populating. For this line, The relative importance of autoionizing states effect, called also resonance effect is studied [fr

  6. Prototype Solar Domestic Hot Water Systems (A collation of Quarterly Reports)

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-02-01

    This report is a collection of quarterly reports from Solar Engineering and Manufacturing Company (SEMCO) covering the period from November 1976 through September 1977. SEMCO, under NASA/MSFC Contract NAS8-32248, is developing two prototype solar domestic hot water systems consisting of the following subsystems: collector, storage, control, transport, and auxiliary energy. These two systems are being installed at sites in Loxahatchee, Florida (OTS-27) and Macon, Georgia (OTS-28).

  7. X-ray emitting hot plasma in solar active regions observed by the SphinX spectrometer

    Science.gov (United States)

    Miceli, M.; Reale, F.; Gburek, S.; Terzo, S.; Barbera, M.; Collura, A.; Sylwester, J.; Kowalinski, M.; Podgorski, P.; Gryciuk, M.

    2012-08-01

    Aims: The detection of very hot plasma in the quiescent corona is important for diagnosing heating mechanisms. The presence and the amount of such hot plasma is currently debated. The SphinX instrument on-board the CORONAS-PHOTON mission is sensitive to X-ray emission of energies well above 1 keV and provides the opportunity to detect the hot plasma component. Methods: We analysed the X-ray spectra of the solar corona collected by the SphinX spectrometer in May 2009 (when two active regions were present). We modelled the spectrum extracted from the whole Sun over a time window of 17 days in the 1.34-7 keV energy band by adopting the latest release of the APED database. Results: The SphinX broadband spectrum cannot be modelled by a single isothermal component of optically thin plasma and two components are necessary. In particular, the high statistical significance of the count rates and the accurate calibration of the spectrometer allowed us to detect a very hot component at ~7 million K with an emission measure of ~2.7 × 1044 cm-3. The X-ray emission from the hot plasma dominates the solar X-ray spectrum above 4 keV. We checked that this hot component is invariably present in both the high and low emission regimes, i.e. even excluding resolvable microflares. We also present and discuss the possibility of a non-thermal origin (which would be compatible with a weak contribution from thick-target bremsstrahlung) for this hard emission component. Conclusions: Our results support the nanoflare scenario and might confirm that a minor flaring activity is ever-present in the quiescent corona, as also inferred for the coronae of other stars.

  8. Thermal performance assessment and improvement of a solar domestic hot water tank with PCM in the mantle

    DEFF Research Database (Denmark)

    Deng, Jie; Furbo, Simon; Kong, Weiqiang

    2018-01-01

    To develop an appropriate solar DHW (Domestic Hot Water) tank for residential dwellings and put it into the European solar thermal market for promotion, thermal performance tests of PCM (Phase Change Material) hot water storage tanks of both a prototype and an improved version with a water volume...

  9. Investigation af a solar heating system for space heating and domestic hot water supply with a high degree of coverage

    DEFF Research Database (Denmark)

    Vejen, Niels Kristian

    1999-01-01

    A solar storage tank for space heating and domestic hot water supply was designed and testet in af laboratory test facility.......A solar storage tank for space heating and domestic hot water supply was designed and testet in af laboratory test facility....

  10. Performance analysis of high-concentrated multi-junction solar cells in hot climate

    Science.gov (United States)

    Ghoneim, Adel A.; Kandil, Kandil M.; Alzanki, Talal H.; Alenezi, Mohammad R.

    2018-03-01

    Multi-junction concentrator solar cells are a promising technology as they can fulfill the increasing energy demand with renewable sources. Focusing sunlight upon the aperture of multi-junction photovoltaic (PV) cells can generate much greater power densities than conventional PV cells. So, concentrated PV multi-junction solar cells offer a promising way towards achieving minimum cost per kilowatt-hour. However, these cells have many aspects that must be fixed to be feasible for large-scale energy generation. In this work, a model is developed to analyze the impact of various atmospheric factors on concentrator PV performance. A single-diode equivalent circuit model is developed to examine multi-junction cells performance in hot weather conditions, considering the impacts of both temperature and concentration ratio. The impacts of spectral variations of irradiance on annual performance of various high-concentrated photovoltaic (HCPV) panels are examined, adapting spectra simulations using the SMARTS model. Also, the diode shunt resistance neglected in the existing models is considered in the present model. The present results are efficiently validated against measurements from published data to within 2% accuracy. Present predictions show that the single-diode model considering the shunt resistance gives accurate and reliable results. Also, aerosol optical depth (AOD) and air mass are most important atmospheric parameters having a significant impact on HCPV cell performance. In addition, the electrical efficiency (η) is noticed to increase with concentration to a certain concentration degree after which it decreases. Finally, based on the model predictions, let us conclude that the present model could be adapted properly to examine HCPV cells' performance over a broad range of operating conditions.

  11. Thermal performance behavior of a domestic hot water solar storage tank during consumption operation

    International Nuclear Information System (INIS)

    Dehghan, A.A.; Barzegar, A.

    2011-01-01

    Transient thermal performance behavior of a vertical storage tank of a domestic solar water heating system with a mantle heat exchanger has been investigated numerically in the discharge/consumption mode. It is assumed that the tank is initially stratified during its previous heat storing/charging operation. During the discharging period, the city cold water is fed at the bottom of the tank and hot water is extracted from its top outlet port for consumption. Meanwhile, the collector loop is assumed to be active. The conservation equations in the axis-symmetric cylindrical co-ordinate have been used and discretised by employing the finite volume method. The low Reynolds number (LRN) k - ω model is utilized for treating turbulence in the fluid. The influence of the tank Grashof number, the incoming cold fluid Reynolds number and the size of the inlet port of the heat storage tank on the transient thermal characteristics of the tank is investigated and discussed. It is found that for higher values of Grashof number, the pre-established thermal stratification is well preserved during the discharging operation mode. It is also noticed that in order to have a tank with a proper thermal performance and or have least mixing inside the tank during the consumption period, the tank inflow Reynolds number and or its inflow port diameter should be kept below certain values. In these cases, the storage tank is enabling to provide proper amount of hot water with a proper temperature for consumption purposes.

  12. Performance of a solar dryer using hot air from roof-integrated solar collectors for drying herbs and spices

    Energy Technology Data Exchange (ETDEWEB)

    Janjai, S.; Tung, P. [Silpakorn University, Pathom (Thailand). Dept. of Physics

    2005-11-01

    A solar dryer for drying herbs and spices using hot air from roof-integrated solar collectors was developed. The dryer is a bin type with a rectangular perforated floor. The bin has a dimension of 1.0 m x 2.0 m x 0.7 m. Hot air is supplied to the dryer from fiberglass-covered solar collectors, which also function as the roof of a farmhouse. The total area of the solar collectors is 72 m{sup 2}. To investigate its performance, the dryer was used to dry four batches of rosella flowers and three batches of lemon-grasses during the year 2002-2003. The dryer can be used to dry 200 kg of rosella flowers and lemon-grasses within 4 and 3 days, respectively. The products being dried in the dryer were completely protected from rains and insects and the dried products are of high quality. The solar air heater has an average daily efficiency of 35% and it performs well both as a solar collector and a roof of a farmhouse. (author)

  13. Verification test report on a solar heating and hot water system

    Science.gov (United States)

    1978-01-01

    Information is provided on the development, qualification and acceptance verification of commercial solar heating and hot water systems and components. The verification includes the performances, the efficiences and the various methods used, such as similarity, analysis, inspection, test, etc., that are applicable to satisfying the verification requirements.

  14. Solar heating and hot water system installed at Alderson Broaddus College, Philippi, West Virginia

    Science.gov (United States)

    1981-01-01

    Data needed necessary to evaluate the design and operation of a solar energy heating and hot water system installed in a commercial application are presented. The information includes system descriptions, acceptance test data, schematics, as built drawing, problems encountered, all solutions and photographs of the system at various stages of completion.

  15. Exposure to solar ultraviolet radiation: a hot topic?

    International Nuclear Information System (INIS)

    Vernez, David; Backes, Claudine; Milon, Antoine

    2016-01-01

    The Sun can be harmful to human health, about a certain threshold. More than occasional exposures, it is chronic exposures that are responsible for the majority of the UV-related skin cancers that affect numerous outdoor workers. Solar exposure should not merely be a public health issue, it should also be raised in the working world. (authors)

  16. Investigation and Construction of a Thermosyphoning Solar Hot Water System

    Science.gov (United States)

    Johnson, Harvey

    1978-01-01

    Describes how a thermosyphoning solar water heater capable of heating 110 kilogram of water to 80 degree Celsius and maintaining this temperature for 24 hours was constructed by four students in the fifth form of Sekolah Date Abdul Razak, Seremban, Malaysia in 1976. (HM)

  17. Solar heating and hot water system installed at James Hurst Elementary School, Portsmouth, Virginia

    Science.gov (United States)

    1981-01-01

    Solar heating and a hot water system installed in an elementary school in Portsmouth, Virginia are examined. The building is zoned into four heating/cooling areas. Each area is equipped with an air handling unit that is monitored and controlled by central control and monitoring system. The solar system for the building uses a collector area of 3,630 sq. ft. of flat plate liquid collectors, and a 6,000 gallon storage tank. System descriptions, maintenance reports, detailed component specifications, and design drawings to evaluate this solar system are reported.

  18. About the standard solar model

    International Nuclear Information System (INIS)

    Cahen, S.

    1986-07-01

    A discussion of the still controversial solar helium content is presented, based on a comparison of recent standard solar models. Our last model yields an helium mass fraction ∼0.276, 6.4 SNU on 37 Cl and 126 SNU on 71 Ga

  19. Air-cooled LiBr-water absorption chillers for solar air conditioning in extremely hot weathers

    International Nuclear Information System (INIS)

    Kim, D.S.; Infante Ferreira, C.A.

    2009-01-01

    A low temperature-driven absorption cycle is theoretically investigated for the development of an air-cooled LiBr-water absorption chiller to be combined with low-cost flat solar collectors for solar air conditioning in hot and dry regions. The cycle works with dilute LiBr-water solutions so that risk of LiBr crystallization is less than for commercially available water-cooled LiBr-water absorption chillers even in extremely hot ambient conditions. Two-phase heat exchangers in the system were modelled taking account of the heat and mass transfer resistances in falling film flows by applying the film theory in thermal and concentration boundary layers. Both directly and indirectly air-cooled chillers were modelled by properly combining component models and boundary conditions in a matrix system and solved with an algebraic equation solver. Simulation results predict that the chillers would deliver chilled water around 7.0 deg. C with a COP of 0.37 from 90 deg. C hot water under 35 deg. C ambient condition. At 50 deg. C ambient temperature, the chillers retained about 36% of their cooling power at 35 deg. C ambient. Compared with the directly air-cooled chiller, the indirectly air-cooled chiller presented a cooling power performance reduction of about 30%

  20. System design package for SIMS Prototype System 4, solar heating and domestic hot water

    Energy Technology Data Exchange (ETDEWEB)

    1978-11-01

    This report is a collation of documents and drawings that describe a prototype solar heating and hot water system using air type solar energy collection techniques. The system consists of a modular designed prepackaged solar unit containing solar collctors, a rock storage container, blowers, dampers, ducting, air-to-water heat exchanger, DHW preheat tank, piping and system controls. The system was designed to be installed adjacent to a small single family dwelling. The description, performance specification, subsystem drawings, verification plan/procedure, and hazard analysis of the system are packaged for evaluation of the system with inforation sufficient to assemble a similar system. The prepackage solar unit has been installed at the Mississippi Power and Light Company, Training Facilities, Clinton, Mississippi.

  1. Solar Heating of Buildings and Domestic Hot Water. Revision.

    Science.gov (United States)

    1980-05-01

    tracking mechanism and can collect only direct radiation. Figure 2-9(c) shows a compound parabolic mirror collector . The design of the mirrors allow the...linear-trough, fresnel lens tube collector (c compound parabolic mirror IFigurc 2-9. Cirnicntrating coll’ectors lr solar cncrgy. Direct radiation is...the parabolic trough, the linear-trough fresnel lens, and the compound parabolic mirror. -Figure 2-9(a) shows a linear concentrating or parabolic

  2. Cold-Climate Solar Domestic Hot Water Systems Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Burch, J.; Salasovich, J.; Hillman, T.

    2005-11-01

    The Solar Heating and Lighting Sub-program has set the key goal to reduce the cost of saved energy [Csav, defined as (total cost, $)/(total discounted savings, kWh_thermal)] for solar domestic water heaters (SDWH) by at least 50%. To determine if this goal is attainable and prioritize R&D for cold-climate SDWH, life-cycle analyses were done with hypothetical lower-cost components in glycol, drainback, and thermosiphon systems. Balance-of-system (BOS, everything but the collector) measures included replacing metal components with polymeric versions and system simplification. With all BOS measures in place, Csav could be reduced more than 50% with a low-cost, selectively-coated, glazed polymeric collector, and slightly less than 50% with either a conventional selective metal-glass or a non-selective glazed polymer collector. The largest percent reduction in Csav comes from replacing conventional pressurized solar storage tanks and metal heat exchangers with un-pressurized polymer tanks with immersed polymer heat exchangers, which could be developed with relatively low-risk R&D.

  3. Solar Measurement and Modeling | Grid Modernization | NREL

    Science.gov (United States)

    Measurement and Modeling Solar Measurement and Modeling NREL supports grid integration studies , industry, government, and academia by disseminating solar resource measurements, models, and best practices have continuously gathered basic solar radiation information, and they now gather high-resolution data

  4. Potential application of solar thermal systems for hot water production in Hong Kong

    International Nuclear Information System (INIS)

    Li Hong; Yang Hongxing

    2009-01-01

    This paper presents the evaluation results of conventional solar water heater (SWH) systems and solar assisted heat pump (SAHP) systems for hot water production in Hong Kong. An economic comparison and global warming impact analysis are conducted among the two kinds of solar thermal systems and traditional water heating systems (i.e. electric water heaters and towngas water heaters). The economic comparison results show that solar thermal systems have greater economic benefits than traditional water heating systems. In addition, conventional SWH systems are comparable with the SAHP systems when solar fractions are above 50%. Besides, analysis on the sensitivity of the total equivalent warming impact (TEWI) indicates that the towngas boosted SWH system has the greatest potential in greenhouse gas emission reduction with various solar collector areas and the electricity boosted SWH system has the comparative TEWI with the SAHP systems if its solar fraction is above 50%. As for SAHP systems, the solar assisted air source heat pump (SA-ASHP) system has the least global warming impact. Based on all investigation results, suggestions are given on the selection of solar thermal systems for applications in Hong Kong

  5. Solar heating systems for heating and hot water

    Energy Technology Data Exchange (ETDEWEB)

    Schnaith, G; Dittrich, K

    1980-07-01

    Deutsche Bundesbahn has shown an interest in solar heating systems, too. The items discussed include the useful radiation energy, design features of collectors, heat carrier media, safeguards and profitability studies. The system installed by Deutsche Bundesbahn in the social services building of the Munich-Laim railway workshop is described. In conclusion, the test results of the first few months of service are given. In order to obtain unambiguous results, it appears indispensable to arrange for an additional total trial period of not less than two years and to conduct tests also on further systems presently under construction.

  6. Methods of accounting the hot water consumption modes at the solar installations design

    Directory of Open Access Journals (Sweden)

    Vyacheslav O. Dubkovsky

    2015-06-01

    Full Text Available Peculiarities of the high-powered solar systems for hot water heating are considered. The purpose of work consists in development of methods for accounting the 24-hourly hot water consumption mode, determining the solar systems dynamic descriptions. The basic solar system schemes are analyzed with their shortages from the user satisfaction view point due to sun energy. For the dynamic parameters improvement the use of operative expense tank is examined such receptacle bearing built-in worm-pipe, through which all heat carrier from solar collectors passes before entering the fast heat exchanger which heats a tank-accumulator. The scientific novelty refers to the proof that this tank principal parameter is a not the volume, but the built-in exchanger capacity, determined by the solar collectors field total thermal power. As an ecological constituent of operating costs it is suggested to take into account cost paid for the emission of combustion products. As this method practical application example considered is the solar collectors capacity optimization for a communal enterprise.

  7. Retrofitting Domestic Hot Water Heaters for Solar Water Heating Systems in Single-Family Houses in a Cold Climate: A Theoretical Analysis

    Directory of Open Access Journals (Sweden)

    Björn Karlsson

    2012-10-01

    Full Text Available One of the biggest obstacles to economic profitability of solar water heating systems is the investment cost. Retrofitting existing domestic hot water heaters when a new solar hot water system is installed can reduce both the installation and material costs. In this study, retrofitting existing water heaters for solar water heating systems in Swedish single-family houses was theoretically investigated using the TRNSYS software. Four simulation models using forced circulation flow with different system configurations and control strategies were simulated and analysed in the study. A comparison with a standard solar thermal system was also presented based on the annual solar fraction. The simulation results indicate that the retrofitting configuration achieving the highest annual performance consists of a system where the existing tank is used as storage for the solar heat and a smaller tank with a heater is added in series to make sure that the required outlet temperature can be met. An external heat exchanger is used between the collector circuit and the existing tank. For this retrofitted system an annual solar fraction of 50.5% was achieved. A conventional solar thermal system using a standard solar tank achieves a comparable performance for the same total storage volume, collector area and reference conditions.

  8. Solar heating and hot water system installed at Cherry Hill, New Jersey. [Hotels

    Energy Technology Data Exchange (ETDEWEB)

    1979-05-16

    The solar heating and hot water system installed in existing buildings at the Cherry Hill Inn in Cherry Hill, New Jersey is described in detail. The system went into operation November 8, 1978 and is expected to furnish 31.5% of the overall heating load and 29.8% of the hot water load. The collectors are General Electric Company liquid evacuated tube type. The storage system is an above ground insulated steel water tank with a capacity of 7,500 gallons.

  9. Solar heating, cooling and domestic hot water system installed at Columbia Gas System Service Corporation, Columbus, Ohio

    Science.gov (United States)

    1980-01-01

    The solar energy system installed in the building has 2,978 sq ft of single axis tracking, concentrating collectors and provides solar energy for space heating, space cooling and domestic hot water. A 1,200,000 Btu/hour water tube gas boiler provides hot water for space heating. Space cooling is provided by a 100 ton hot water fired absorption chiller. Domestic hot water heating is provided by a 50 gallon natural gas domestic storage water heater. Extracts from the site files, specification references, drawings, installation, operation and maintenance instructions are included.

  10. Solar heating and hot water system installed at Municipal Building complex, Abbeville, South Carolina

    Science.gov (United States)

    1979-01-01

    Information on the solar energy system installed at the new municipal building for the City of Abbeville, SC is presented, including a description of solar energy system and buildings, lessons learned, and recommendations. The solar space heating system is a direct air heating system. The flat roof collector panel was sized to provide 75% of the heating requirement based on an average day in January. The collectors used are job-built with two layers of filon corrugated fiberglass FRP panels cross lapped make up the cover. The storage consists of a pit filled with washed 3/4 in - 1 1/2 in diameter crushed granite stone. The air handler includes the air handling mechanism, motorized dampers, air circulating blower, sensors, control relays and mode control unit. Solar heating of water is provided only those times when the hot air in the collector is exhausted to the outside.

  11. An experimental investigation with artificial sunlight of a solar hot-water heater

    Science.gov (United States)

    Simon, F. F.

    1976-01-01

    Thermal performance measurements were made of a commercial solar hot water heater in a solar simulator to determine basic performance characteristics of a traditional type of flat plate collector, with and without side reflectors (to increase the solar flux). Information on each of the following was obtained; (1) the effect of flow and incidence angle on the efficiency of a flat plate collector (but only without side reflectors); (2) transient performance under flow and nonflow conditions; (3) the effectiveness of reflectors to increase collector efficiency for a zero radiation angle at fluid temperatures required for solar air conditioning; and (4) the limits of applicability of a collector efficiency correlation based on the Hottel Whillier equation.

  12. Heat Transfer Model for Hot Air Balloons

    Science.gov (United States)

    Llado-Gambin, Adriana

    A heat transfer model and analysis for hot air balloons is presented in this work, backed with a flow simulation using SolidWorks. The objective is to understand the major heat losses in the balloon and to identify the parameters that affect most its flight performance. Results show that more than 70% of the heat losses are due to the emitted radiation from the balloon envelope and that convection losses represent around 20% of the total. A simulated heating source is also included in the modeling based on typical thermal input from a balloon propane burner. The burner duty cycle to keep a constant altitude can vary from 10% to 28% depending on the atmospheric conditions, and the ambient temperature is the parameter that most affects the total thermal input needed. The simulation and analysis also predict that the gas temperature inside the balloon decreases at a rate of -0.25 K/s when there is no burner activity, and it increases at a rate of +1 K/s when the balloon pilot operates the burner. The results were compared to actual flight data and they show very good agreement indicating that the major physical processes responsible for balloon performance aloft are accurately captured in the simulation.

  13. Long term performance of a solar floor and hot water heating house; Taiyonetsu yukadanbo kyuto jutaku no choki seino

    Energy Technology Data Exchange (ETDEWEB)

    Udagawa, M [Kogakuin University, Tokyo (Japan)

    1997-11-25

    Outlined herein are measured energy consumption followed for 12 years for a totally electrified solar house with a floor-heating and hot-water heating system. In the solar system, hot water generated by the solar collector is sent, via a surge tank, to a living room, dining room and study to heat their concrete floors, and recycled back to the collector after heating the heat-storage tank for hot water supply. The collector is of plate type, consisting of 6 units, each with a white glass sheet as the heat-collecting membrane for selectively absorbing heat. Its total heat-collecting area is 11.4m{sup 2}. Long-term performance of the solar system installed for floor and hot-water heating in a totally electrified solar house, is analyzed by the measured results collected for 12 years. The house consumes secondary energy of 11.7MWh/year on the average, which is approximately 20% lower that that required for a house of the equivalent size. The solar system has been operated smoothly, to supply 46 and 35% of the required heat for hot-water and floor heating. It is however estimated that annual heat loss reaches 34% in the hot-water heating system, including that in the electric hot-water generator, and prevention of heat loss is one of the major themes for the future system designs. 4 refs., 5 figs.

  14. Temperature distribution of a hot water storage tank in a simulated solar heating and cooling system

    Science.gov (United States)

    Namkoong, D.

    1976-01-01

    A 2,300-liter hot water storage tank was studied under conditions simulating a solar heating and cooling system. The initial condition of the tank, ranging from 37 C at the bottom to 94 C at the top, represented a condition midway through the start-up period of the system. During the five-day test period, the water in the tank gradually rose in temperature but in a manner that diminished its temperature stratification. Stratification was found not to be an important factor in the operation of the particular solar system studied.

  15. An experimental study of solar desalination using free jets and an auxiliary hot air stream

    Science.gov (United States)

    Eid, Eldesouki I.; Khalaf-Allah, Reda A.; Dahab, Mohamed A.

    2018-04-01

    An experimental study for a solar desalination system based on jet-humidification with an auxiliary perpendicular hot air stream was carried out at Suez city, Egypt 29.9668°N, 32.5498°E. The tests were done from May to October 2016. The effects of nozzles situations and nozzle diameter with and without hot air stream on fresh water productivity were monitored. The results show that; the lateral and downward jets from narrow nozzles have more productivities than other situations. The hot air stream has to be adapted at a certain flow rate to get high values of productivity. The system productivity is (5.6 L/m 2 ), the estimated cost is (0.030063 / L) and the efficiency is 32.8%.

  16. System design package for IBM system one: solar heating and domestic hot water

    Science.gov (United States)

    1977-01-01

    This report is a collation of documents and drawings that describe a prototype solar heating and hot water system using air as the collector fluid and a pebble bed for heat storage. The system was designed for installation into a single family dwelling. The description, performance specification, subsystem drawings, verification plan/procedure, and hazard analysis of the system was packaged for evaluation of the system with information sufficient to assemble a similar system.

  17. System Design Package for SIMS Prototype System 3, Solar Heating and Domestic Hot Water

    Science.gov (United States)

    1978-01-01

    A collation of documents and drawings are presented that describe a prototype solar heating and hot water system using liquid flat plate collectors and a gas or electric furnace energy subsystem. The system was designed for installation into a single-family dwelling. The description, performance specification, subsystem drawings, verification plan/procedure, and hazard analysis of the system are packaged for evaluation of the system with information sufficient to assemble a similar system.

  18. An assessment of solar hot water heating in the Washington, D.C. area - Implications for local utilities

    Science.gov (United States)

    Stuart, M. W.

    1980-04-01

    A survey of residential solar hot water heating in the Washington, D.C. area is presented with estimates of the total solar energy contribution per year. These estimates are examined in relation to a local utility's peak-load curves to determine the impact of a substantial increase in solar domestic hot water use over the next 20 yr in the area of utility management. The results indicate that a 10% market penetration of solar water heaters would have no detrimental effect on the utility's peak-load profile and could save several million dollars in new plant construction costs.

  19. The impact of the hot tap water load pattern in the industrial hall on the energy yield from solar collectors

    Science.gov (United States)

    Fidorów-Kaprawyl, Natalia; Dudkiewicz, Edyta

    2017-11-01

    The systems using solar energy, popular in Poland, can be used to supply hot water for the installation used by employees of industrial halls. In manufacturing plants, employing a large number of people, the demand for hot water is practically constant throughout the year and is characterized by periodic use at the end of each work shift. Dynamics of the hot water consumption depends on the number of shifts as well as working days and holidays. Additionally the maximum hot tap water demand occurs in the whole period of installation operation. In polish climatic conditions the solar collectors' systems have the largest capacity in the summer, while in winter they need to be assisted. Beside that the supply of renewable energy is uneven and depends on weather conditions. In the paper the one-hour step analysis concerning the dependence of the load pattern of the hot tap water preparation system on the energy yield from solar collectors had been performed.

  20. Modeling deflagration waves out of hot spots

    Science.gov (United States)

    Partom, Yehuda

    2017-01-01

    It is widely accepted that shock initiation and detonation of heterogeneous explosives comes about by a two-step process known as ignition and growth. In the first step a shock sweeping through an explosive cell (control volume) creates hot spots that become ignition sites. In the second step, deflagration waves (or burn waves) propagate out of those hot spots and transform the reactant in the cell into reaction products. The macroscopic (or average) reaction rate of the reactant in the cell depends on the speed of those deflagration waves and on the average distance between neighboring hot spots. Here we simulate the propagation of deflagration waves out of hot spots on the mesoscale in axial symmetry using a 2D hydrocode, to which we add heat conduction and bulk reaction. The propagation speed of the deflagration waves may depend on both pressure and temperature. It depends on pressure for quasistatic loading near ambient temperature, and on temperature at high temperatures resulting from shock loading. From the simulation we obtain deflagration fronts emanating out of the hot spots. For 8 to 13 GPa shocks, the emanating fronts propagate as deflagration waves to consume the explosive between hot spots. For higher shock levels deflagration waves may interact with the sweeping shock to become detonation waves on the mesoscale. From the simulation results we extract average deflagration wave speeds.

  1. Solar electricity: An effective asset to supply urban loads in hot climates

    Science.gov (United States)

    Robert, Fabien Chidanand; Gopalan, Sundararaman

    2018-04-01

    While human population has been multiplied by four in the last hundred years, the world energy consumption was multiplied by ten. The common method of using fossil fuels to provide energy and electricity has dangerously disturbed nature's and climate's balance. It has become urgent and crucial to find sustainable and eco-friendly alternatives to preserve a livable environment with unpolluted air and water. Renewable energy is the unique eco-friendly opportunity known today. The main challenge of using renewable energy is to ensure the constant balance of electricity demand and generation on the electrical grid. This paper investigates whether the solar electricity generation is correlated with the urban electricity consumption in hot climates. The solar generation and total consumption have been compared for three cities in Florida. The hourly solar generation has been found to be highly correlated with the consumption that occurs 6 h later, while the monthly solar generation is correlated with the monthly energy consumption. Producing 30% of the electricity using solar energy has been found to compensate partly for the monthly variation in the urban electricity demand. In addition, if 30% of the world electricity is produced using solar, global CO2 emissions would be reduced by 11.7% (14.6% for India). Thus, generating 30% solar electricity represents a valuable asset for urban areas situated in hot climates, reducing the need for electrical operating reserve, providing local supply with minimal transmission losses, but above all reducing the need for fossil fuel electricity and reducing global CO2 emission.

  2. Performance optimization of evacuated tube collector for solar cooling of a house in hot climate

    Science.gov (United States)

    Ghoneim, Adel A.

    2018-02-01

    Evacuating the space connecting cover and absorber significantly improves evacuated tube collector (ETC) performance. So, ETCs are progressively utilised all over the world. The main goal of current study is to explore ETC thermal efficiency in hot and severe climate like Kuwait weather conditions. A collector test facility was installed to record ETC thermal performance for one-year period. An extensively developed model for ETCs is presented, employing complete optical and thermal assessment. This study analyses separately optics and heat transfer in the evacuated tubes, allowing the analysis to be extended to different configurations. The predictions obtained are in agreement with experimental. The optimum collector parameters (collector tube length and diameter, mass flow rate and collector tilt angle) are determined. The present results indicate that the optimum tube length is 1.5 m, as at this length a significant improvement is achieved in efficiency for different tube diameters studied. Finally, the heat generated from ETCs is used for solar cooling of a house. Results of the simulation of cooling system indicate that an ETC of area 54 m2, tilt angle of 25° and storage tank volume of 2.1 m3 provides 80% of air-conditioning demand in a house located in Kuwait.

  3. Resonant tunneling diodes as energy-selective contacts used in hot-carrier solar cells

    International Nuclear Information System (INIS)

    Takeda, Yasuhiko; Sugimoto, Noriaki; Ichiki, Akihisa; Kusano, Yuya; Motohiro, Tomoyoshi

    2015-01-01

    Among the four features unique to hot-carrier solar cells (HC-SCs): (i) carrier thermalization time and (ii) carrier equilibration time in the absorber, (iii) energy-selection width and (iv) conductance of the energy-selective contacts (ESCs), requisites of (i)-(iii) for high conversion efficiency have been clarified. We have tackled the remaining issues related to (iv) in the present study. The detailed balance model of HC-SC operation has been improved to involve a finite value of the ESC conductance to find the required values, which in turn has been revealed to be feasible using resonant tunneling diodes (RTDs) consisting of semiconductor quantum dots (QDs) and quantum wells (QWs) by means of a formulation to calculate the conductance of the QD- and QW-RTDs derived using the rigorous solutions of the effective-mass Hamiltonians. Thus, all of the four requisites unique to HC-SCs to achieve high conversion efficiency have been elucidated, and the two requisites related to the ESCs can be fulfilled using the QD- and QW-RTDs

  4. Resonant tunneling diodes as energy-selective contacts used in hot-carrier solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Yasuhiko, E-mail: takeda@mosk.tytlabs.co.jp; Sugimoto, Noriaki [Toyota Central Research and Development Laboratories, Inc., 41-1, Yokomichi, Nagakute, Aichi 480-1192 (Japan); Ichiki, Akihisa [Green Mobility Collaborative Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Kusano, Yuya [Green Mobility Collaborative Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Toyota Motor Corp., 1200 Mishuku, Susono, Shizuoka 410-1193 (Japan); Motohiro, Tomoyoshi [Toyota Central Research and Development Laboratories, Inc., 41-1, Yokomichi, Nagakute, Aichi 480-1192 (Japan); Green Mobility Collaborative Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan)

    2015-09-28

    Among the four features unique to hot-carrier solar cells (HC-SCs): (i) carrier thermalization time and (ii) carrier equilibration time in the absorber, (iii) energy-selection width and (iv) conductance of the energy-selective contacts (ESCs), requisites of (i)-(iii) for high conversion efficiency have been clarified. We have tackled the remaining issues related to (iv) in the present study. The detailed balance model of HC-SC operation has been improved to involve a finite value of the ESC conductance to find the required values, which in turn has been revealed to be feasible using resonant tunneling diodes (RTDs) consisting of semiconductor quantum dots (QDs) and quantum wells (QWs) by means of a formulation to calculate the conductance of the QD- and QW-RTDs derived using the rigorous solutions of the effective-mass Hamiltonians. Thus, all of the four requisites unique to HC-SCs to achieve high conversion efficiency have been elucidated, and the two requisites related to the ESCs can be fulfilled using the QD- and QW-RTDs.

  5. Simulation of the solar hot water systems diffusion: the case of Greece

    International Nuclear Information System (INIS)

    Sidiras, D.; Koukios, E.

    2004-01-01

    The main object of this paper is the documentation and study of the main factors behind the spectacular diffusion of solar energy use for domestic hot water production in Greece. The time pattern of the diffusion of flat-plate solar collectors since its 'out of the blue' first appearance in 1974, shows that the diffusion rate grew exponentially at first, with the annual sales figure reaching 91,000 m 2 by 1980. A rate slow down in the early 1980s was followed by a brief period of explosive growth, with the annual sales figure reaching its peak value of more than 185,000 m 2 in mid-1980s. A rapid decline of the growth rate down to the present annual sales level followed. The installed solar collectors pattern has the characteristic form of an S-shape curve, representing the overall penetration of the flat-plate solar collector use for domestic hot water production in the Greek economy and society. This evolution has gone through an inflection point around 1987, i.e. at a time when about 1,000,000 m 2 of collectors had already been installed. By the year 2000, about 2,070,000 m 2 of collectors had been installed, with a tendency to level off by 2010, unless some the present conditions determining this phenomenon change. (author)

  6. Development of a direct expansion solar assisted heat pump for hot water supply

    International Nuclear Information System (INIS)

    Abdesselam Hamloui; Ong, K.S.; Than Cheok Fah; Masjuki Hassan

    2000-01-01

    Experimental investigations were conducted on the direct expansion solar assisted Heat Pump (DESAHP). Refrigerant R-22 was expanded in the solar collector which also acted as the evaporator in a conventional vapor compression refrigerating machine. The experiments were conducted under conditions of high and low solar radiation, with evaporator completely shaded from the sun, and at night. System thermal performance was determined by measuring refrigerant flow rate, temperature and pressure at numerous points in the system. The results showed that 227-l of water could be heated from 3O degree to 55 degree C in about 105 minutes. Higher water temperatures were obtained during hot sunny days. The coefficient of performance of heating, COP h , ranged from 11 to 4.7, depending upon operating conditions. The total saving of electric energy during hot sunny days was about 460 %. It means that for 1 kWh of electrical input to the system, we achieve 4.6 kWh. This percentage decreases as the evaporator temperature decreases and is a function of solar energy input. (Author)

  7. Effects of solar radiation on endurance exercise capacity in a hot environment.

    Science.gov (United States)

    Otani, Hidenori; Kaya, Mitsuharu; Tamaki, Akira; Watson, Phillip; Maughan, Ronald J

    2016-04-01

    The present study investigated the effects of variations in solar radiation on endurance exercise capacity and thermoregulatory responses in a hot environment. Eight male volunteers performed four cycle exercise trials at 70 % maximum oxygen uptake until exhaustion in an environmental chamber maintained at 30 °C and 50 % relative humidity. Volunteers were tested under four solar radiation conditions: 800, 500, 250 and 0 W/m(2). Exercise time to exhaustion was less on the 800 W/m(2) trial (23 ± 4 min) than on all the other trials (500 W/m(2) 30 ± 7 min; P 0.05). Mean skin temperature was higher on the 800 W/m(2) trial than the 250 and 0 W/m(2) trials (P solar radiation increases.

  8. Modeling of solar polygeneration plant

    Science.gov (United States)

    Leiva, Roberto; Escobar, Rodrigo; Cardemil, José

    2017-06-01

    In this work, a exergoeconomic analysis of the joint production of electricity, fresh water, cooling and process heat for a simulated concentrated solar power (CSP) based on parabolic trough collector (PTC) with thermal energy storage (TES) and backup energy system (BS), a multi-effect distillation (MED) module, a refrigeration absorption module, and process heat module is carried out. Polygeneration plant is simulated in northern Chile in Crucero with a yearly total DNI of 3,389 kWh/m2/year. The methodology includes designing and modeling a polygeneration plant and applying exergoeconomic evaluations and calculating levelized cost. Solar polygeneration plant is simulated hourly, in a typical meteorological year, for different solar multiple and hour of storage. This study reveals that the total exergy cost rate of products (sum of exergy cost rate of electricity, water, cooling and heat process) is an alternative method to optimize a solar polygeneration plant.

  9. Solar models: An historical overview

    International Nuclear Information System (INIS)

    Bahcall, John N.

    2003-01-01

    I will summarize in four slides the 40 years of development of the standard solar model that is used to predict solar neutrino fluxes and then describe the current uncertainties in the predictions. I will dispel the misconception that the p-p neutrino flux is determined by the solar luminosity and present a related formula that gives, in terms of the p-p and 7 Be neutrino fluxes, the ratio of the rates of the two primary ways of terminating the p-p fusion chain. I will also attempt to explain why it took so long, about three and a half decades, to reach a consensus view that new physics is being learned from solar neutrino experiments. Finally, I close with a personal confession

  10. Primary energy consumption of the dwelling with solar hot water system and biomass boiler

    International Nuclear Information System (INIS)

    Berković-Šubić, Mihaela; Rauch, Martina; Dović, Damir; Andrassy, Mladen

    2014-01-01

    Highlights: • Methodology for determing delivered and primary energy is developed. • Conventional and solar hot water system are analyzed. • Influence of system components, heat losses and energy consumption is explored. • Savings when using solar system in delivered energy is 30% and in primary 75%. • Dwelling with higher Q H,nd has 60% shorter payback period. - Abstract: This paper presents a new methodology, based on the energy performance of buildings Directive related European norms. It is developed to overcome ambiguities and incompleteness of these standards in determining the delivered and primary energy. The available procedures from the present “Algorithm for determining the energy demands and efficiency of technical systems in buildings”, normally used for energy performance certification of buildings, also allow detailed analyzes of the influence of particular system components on the overall system energy efficiency. The calculation example is given for a Croatian reference dwelling, equipped with a solar hot water system, backed up with a biomass boiler for space heating and domestic hot water purposes as a part of the dwelling energy performance certification. Calculations were performed for two cases corresponding to different levels of the dwelling thermal insulation with an appropriate heating system capacity, in order to investigate the influence of the building heat losses on the system design and energy consumption. The results are compared against those obtained for the conventional system with a gas boiler in terms of the primary energy consumption as well as of investment and operating costs. These results indicate great reduction in both delivered and primary energy consumption when a solar system with biomass boiler is used instead of the conventional one. Higher savings are obtained in the case of the dwelling with higher energy need for space heating. Such dwellings also have a shorter payback period than the ones with

  11. Models of diffuse solar radiation

    Energy Technology Data Exchange (ETDEWEB)

    Boland, John; Ridley, Barbara [Centre for Industrial and Applied Mathematics, University of South Australia, Mawson Lakes Boulevard, Mawson Lakes, SA 5095 (Australia); Brown, Bruce [Department of Statistics and Applied Probability, National University of Singapore, Singapore 117546 (Singapore)

    2008-04-15

    For some locations both global and diffuse solar radiation are measured. However, for many locations, only global is measured, or inferred from satellite data. For modelling solar energy applications, the amount of radiation on a tilted surface is needed. Since only the direct component on a tilted surface can be calculated from trigonometry, we need to have diffuse on the horizontal available. There are regression relationships for estimating the diffuse on a tilted surface from diffuse on the horizontal. Models for estimating the diffuse radiation on the horizontal from horizontal global that have been developed in Europe or North America have proved to be inadequate for Australia [Spencer JW. A comparison of methods for estimating hourly diffuse solar radiation from global solar radiation. Sol Energy 1982; 29(1): 19-32]. Boland et al. [Modelling the diffuse fraction of global solar radiation on a horizontal surface. Environmetrics 2001; 12: 103-16] developed a validated model for Australian conditions. We detail our recent advances in developing the theoretical framework for the approach reported therein, particularly the use of the logistic function instead of piecewise linear or simple nonlinear functions. Additionally, we have also constructed a method, using quadratic programming, for identifying values that are likely to be erroneous. This allows us to eliminate outliers in diffuse radiation values, the data most prone to errors in measurement. (author)

  12. Enhancement of stack ventilation in hot and humid climate using a combination of roof solar collector and vertical stack

    Energy Technology Data Exchange (ETDEWEB)

    Yusoff, Wardah Fatimah Mohammad; Salleh, Elias [Department of Architecture, Faculty of Design and Architecture, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Adam, Nor Mariah [Department of Mechanical and Manufacturing Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Sapian, Abdul Razak [Department of Architecture, Kulliyyah of Architecture and Environmental Design, International Islamic University Malaysia, P.O. Box 10, 50728 Kuala Lumpur (Malaysia); Yusof Sulaiman, Mohamad [Solar Energy Research Institute, 3rd Floor, Tun Sri Lanang Library Building, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2010-10-15

    In the hot and humid climate, stack ventilation is inefficient due to small temperature difference between the inside and outside of naturally ventilated buildings. Hence, solar induced ventilation is a feasible alternative in enhancing the stack ventilation. This paper aims to investigate the effectiveness of a proposed solar induced ventilation strategy, which combines a roof solar collector and a vertical stack, in enhancing the stack ventilation performance in the hot and humid climate. The methodology selected for the investigation is physical experimental modelling which was carried out in the actual environment. The results are presented and discussed in terms of two performance variables: air temperature and air velocity. The findings indicate that the proposed strategy is able to enhance the stack ventilation, both in semi-clear sky and overcast sky conditions. The highest air temperature difference between the air inside the stack and the ambient air (T{sub i}-T{sub o}) is achieved in the semi-clear sky condition, which is about 9.9 C (45.8 C-35.9 C). Meanwhile, in the overcast sky condition, the highest air temperature difference (T{sub i}-T{sub o}) is 6.2 C (39.3 C-33.1 C). The experimental results also indicate good agreement with the theoretical results for the glass temperature, the air temperature in the roof solar collector's channel and the absorber temperature. The findings also show that wind has significant effect to the induced air velocity by the proposed strategy. (author)

  13. Energetical and ecological assessment of solar- and heat pump technologies for hot water preparation and space heating in Austria

    International Nuclear Information System (INIS)

    Faninger, G.

    1991-11-01

    Solar and heat pump systems have been proved in many applications on the market. To achieve an efficient energy output it is necessary to consider the special conditions of these technologies. The energetical and ecological criteria of solar and heat pump systems for hot water preparation and space heating are analysed on the basis of experimental data. (author)

  14. High performance in low-flow solar domestic hot water systems

    Energy Technology Data Exchange (ETDEWEB)

    Dayan, M.

    1997-12-31

    Low-flow solar hot water heating systems employ flow rates on the order of 1/5 to 1/10 of the conventional flow. Low-flow systems are of interest because the reduced flow rate allows smaller diameter tubing, which is less costly to install. Further, low-flow systems result in increased tank stratification. Lower collector inlet temperatures are achieved through stratification and the useful energy produced by the collector is increased. The disadvantage of low-flow systems is the collector heat removal factor decreases with decreasing flow rate. Many solar domestic hot water systems require an auxiliary electric source to operate a pump in order to circulate fluid through the solar collector. A photovoltaic driven pump can be used to replace the standard electrical pump. PV driven pumps provide an ideal means of controlling the flow rate, as pumps will only circulate fluid when there is sufficient radiation. Peak performance was always found to occur when the heat exchanger tank-side flow rate was approximately equal to the average load flow rate. For low collector-side flow rates, a small deviation from the optimum flow rate will dramatically effect system performance.

  15. The Use of Solar Energy for Preparing Domestic Hot Water in a Multi-Storey Building

    Directory of Open Access Journals (Sweden)

    Giedrius Šiupšinskas

    2012-12-01

    Full Text Available The article analyses the possibilities of solar collectors used for a domestic hot water system and installed on the roofs of modernized multi-storey buildings under the existing climate conditions. A number of combinations of flat plate and vacuum solar collectors with accumulation tank systems of various sizes have been examined. Heat from the district heating system is used as an additional heat source for preparing domestic hot water. The paper compares calculation results of energy and economy regarding the combinations of flat plate and vacuum solar collectors and the size of the accumulation tank. The influence of variations in the main indicators on the final economic results has also been evaluated. Research has been supported applying EC FP7 CONCERTO program (‘‘Sustainable Zero Carbon ECO-Town Developments Improving Quality of Life across EU - ECO-Life’’ (ECO-Life Project Contract No. TREN/FP7EN/239497/”ECOLIFE”.Article in Lithuanian

  16. A model for the origin of solar wind stream interfaces

    International Nuclear Information System (INIS)

    Hundhausen, A.J.; Burlaga, L.F.

    1975-01-01

    The basic variations in solar wind properties that have been observed at 'stream interfaces' near 1 AU are explained by a gas dynamic model in which a radially propagating stream, produced by a temperature variation in the solar envelope, steepens nonlinearly while moving through interplanetary space. The region thus identified with the stream interface separates the ambient solar wind from the fresh hot material originally in the stream. However, the interface regions given by the present model are thicker than most stream interfaces observed in the solar wind, a fact suggesting that some additional physical process may be important in determining that thickness. Variations in the density, speed, or Alfven pressure alone appear not to produce streams with such an interface

  17. To built a solar hot water heater to work the sustainability problem

    Directory of Open Access Journals (Sweden)

    Carretero Gómez, María Begoña

    2012-01-01

    Full Text Available We are commemorating the Education Decade for Sustainable Development. If we want to create positive towards our environment and its sustainable development we have to begin working at school. It is necessary to show our students what problems of the environment are and which solutions can be adopted. That is the reason we have planned this activity in our secondary school. We do think that by doing daily activities we have a good opportunity to fulfil this goal. An example of such experiences is the fabrication of a solar hot water heater to make them and their families more environment conscience.

  18. Design and modeling of low temperature solar thermal power station

    International Nuclear Information System (INIS)

    Shankar Ganesh, N.; Srinivas, T.

    2012-01-01

    Highlights: ► The optimum conditions are different for efficiency and power conditions. ► The current model works up to a maximum separator temperature of 150 °C. ► The turbine concentration influences the high pressure. ► High solar beam radiation and optimized cycle conditions give low collector cost. -- Abstract: During the heat recovery in a Kalina cycle, a binary aqua–ammonia mixture changes its state from liquid to vapor, the more volatile ammonia vaporizes first and then the water starts vaporization to match temperature profile of the hot fluid. In the present work, a low temperature Kalina cycle has been investigated to optimize the heat recovery from solar thermal collectors. Hot fluid coming from solar parabolic trough collector with vacuum tubes is used to generate ammonia rich vapor in a boiler for power generation. The turbine inlet conditions are optimized to match the variable hot fluid temperature with the intermittent nature of the solar radiation. The key parameters discussed in this study are strong solution concentration, separator temperature which affects the hot fluid inlet temperature and turbine ammonia concentration. Solar parabolic collector system with vacuum tubes has been designed at the optimized power plant conditions. This work can be used in the selection of boiler, separator and turbine conditions to maximize the power output as well as efficiency of power generation system. The current model results a maximum limit temperature for separator as 150 °C at the Indian climatic conditions. A maximum specific power of 105 kW per kg/s of working fluid can be obtained at 80% of strong solution concentration with 140 °C separator temperature. The corresponding plant and cycle efficiencies are 5.25% and 13% respectively. But the maximum efficiencies of 6% and 15% can be obtained respectively for plant and Kalina cycle at 150 °C of separator temperature.

  19. NO THERMAL INVERSION AND A SOLAR WATER ABUNDANCE FOR THE HOT JUPITER HD 209458B FROM HST /WFC3 SPECTROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    Line, Michael R. [NASA Ames Research Center, Moffet Field, CA 94035 (United States); Stevenson, Kevin B.; Bean, Jacob; Kreidberg, Laura [Department of Astronomy and Astrophysics, University of Chicago, 5640 S Ellis Avenue, Chicago, IL 60637 (United States); Desert, Jean-Michel [University of Amsterdam (Netherlands); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Madhusudhan, Nikku [Institute of Astronomy, University of Cambridge, Cambridge CB3 0HA (United Kingdom); Showman, Adam P. [Department of Planetary Sciences and Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd., Tucson, AZ 85721 (United States); Diamond-Lowe, Hannah [Department of Astronomy, Harvard Smithsonian Center for Astrophysics, 60 Garden Street, MS-10, Cambridge, MA 02138 (United States)

    2016-12-01

    The nature of the thermal structure of hot Jupiter atmospheres is one of the key questions raised by the characterization of transiting exoplanets over the past decade. There have been claims that many hot Jupiters exhibit atmospheric thermal inversions. However, these claims have been based on broadband photometry rather than the unambiguous identification of emission features with spectroscopy, and the chemical species that could cause the thermal inversions by absorbing stellar irradiation at high altitudes have not been identified despite extensive theoretical and observational effort. Here we present high-precision Hubble Space Telescope WFC3 observations of the dayside thermal emission spectrum of the hot Jupiter HD 209458b, which was the first exoplanet suggested to have a thermal inversion. In contrast to previous results for this planet, our observations detect water in absorption at 6.2 σ confidence. When combined with Spitzer photometry, the data are indicative of a monotonically decreasing temperature with pressure over the range of 1–0.001 bars at 7.7 σ confidence. We test the robustness of our results by exploring a variety of model assumptions, including the temperature profile parameterization, presence of a cloud, and choice of Spitzer data reduction. We also introduce a new analysis method to determine the elemental abundances from the spectrally retrieved mixing ratios with thermochemical self-consistency and find plausible abundances consistent with solar metallicity (0.06–10 × solar) and carbon-to-oxygen ratios less than unity. This work suggests that high-precision spectrophotometric results are required to robustly infer thermal structures and compositions of extrasolar planet atmospheres and to perform comparative exoplanetology.

  20. Hot water tank for use with a combination of solar energy and heat-pump desuperheating

    Science.gov (United States)

    Andrews, John W.

    1983-06-28

    A water heater or system which includes a hot water tank having disposed therein a movable baffle to function as a barrier between the incoming volume of cold water entering the tank and the volume of heated water entering the tank which is heated by the circulation of the cold water through a solar collector and/or a desuperheater of a heat pump so as to optimize the manner in which heat is imparted to the water in accordance to the demand on the water heater or system. A supplemental heater is also provided and it is connected so as to supplement the heating of the water in the event that the solar collector and/or desuperheater cannot impart all of the desired heat input into the water.

  1. Lead Acetate Based Hybrid Perovskite Through Hot Casting for Planar Heterojunction Solar Cells

    Science.gov (United States)

    Shin, Gwang Su; Choi, Won-Gyu; Na, Sungjae; Gökdemir, Fatma Pinar; Moon, Taeho

    2018-03-01

    Flawless coverage of a perovskite layer is essential in order to achieve realistic high-performance planar heterojunction solar cells. We present that high-quality perovskite layers can be efficiently formed by a novel hot casting route combined with MAI (CH3NH3I) and non-halide lead acetate (PbAc2) precursors under ambient atmosphere. Casting temperature is controlled to produce various perovskite microstructures and the resulted crystalline layers are found to be comprised of closely packed islands with a smooth surface structure. Lead acetate employed perovskite solar cells are fabricated using PEDOT:PSS and PCBM charge transporting layers, in p- i- n type planar architecture. Especially, the outstanding open-circuit voltage demonstrates the high crystallinity and dense coverage of the produced perovskite layers by this facile route.

  2. Hot water tank for use with a combination of solar energy and heat-pump desuperheating

    Science.gov (United States)

    Andrews, J.W.

    1980-06-25

    A water heater or system is described which includes a hot water tank having disposed therein a movable baffle to function as a barrier between the incoming volume of cold water entering the tank and the volume of heated water entering the tank which is heated by the circulation of the cold water through a solar collector and/or a desuperheater of a heat pump so as to optimize the manner in which heat is imparted to the water in accordance to the demand on the water heater or system. A supplemental heater is also provided and it is connected so as to supplement the heating of the water in the event that the solar collector and/or desuperheater cannot impart all of the desired heat input into the water.

  3. Technology Solutions for New and Existing Homes Case Study: Addressing Multifamily Piping Losses with Solar Hot Water

    Energy Technology Data Exchange (ETDEWEB)

    D. Springer, M. Seitzler, and C. Backman

    2016-12-01

    Sun Light & Power, a San Francisco Bay Area solar design-build contractor, teamed with the U.S. Department of Energy’s Building America partner the Alliance for Residential Building Innovation (ARBI) to study this heat-loss issue. The team added three-way valves to the solar water heating systems for two 40-unit multifamily buildings. In these systems, when the stored solar hot water is warmer than the recirculated hot water returning from the buildings, the valves divert the returning water to the solar storage tank instead of the water heater. This strategy allows solar-generated heat to be applied to recirculation heat loss in addition to heating water that is consumed by fixtures and appliances.

  4. Solar heating, cooling, and domestic hot water system installed at Kaw Valley State Bank and Trust Company, Topeka, Kansas

    Science.gov (United States)

    1980-01-01

    The building has approximately 5600 square feet of conditioned space. Solar energy was used for space heating, space cooling, and preheating domestic hot water (DHW). The solar energy system had an array of evacuated tube-type collectors with an area of 1068 square feet. A 50/50 solution of ethylene glycol and water was the transfer medium that delivered solar energy to a tube-in-shell heat exchanger that in turn delivered solar heated water to a 1100 gallon pressurized hot water storage tank. When solar energy was insufficient to satisfy the space heating and/or cooling demand, a natural gas-fired boiler provided auxiliary energy to the fan coil loops and/or the absorption chillers. Extracts from the site files, specification references, drawings, and installation, operation and maintenance instructions are presented.

  5. American Recovery and Reinvestment Act (ARRA) Federal Energy Management Program Technical Assistance Project 281 Solar Hot Water Application Assessment for U.S. Army IMCOM-Southeast Region

    Energy Technology Data Exchange (ETDEWEB)

    Russo, Bryan J.; Chvala, William D.

    2010-09-30

    The Energy Independence and Security Act of 2007 requires installations (EISA) to install solar systems of sufficient capacity to provide 30% of service hot water in new construction and renovations where cost-effective. However, installations are struggling with how to implement solar hot water, and while several installations are installing solar hot water on a limited basis, paybacks remain long. Pacific Northwest National Laboratory (PNNL) was tasked to address this issue to help determine how best to implement solar hot water projects. This documents discusses the results of that project.

  6. Assessing the economic aspects of solar hot water production in Greece

    International Nuclear Information System (INIS)

    Haralambopoulos, D.; Kovras, H.

    1997-01-01

    The long-term performance of various systems was determined and the economic aspects of solar hot water production were investigated in this work. The effect of the collector inclination angle, collector area and storage volume was examined for all systems, and various climatic conditions and their payback period was calculated. It was found that the collector inclination angle does not have a significant effect on system performance. Large collector areas have a diminishing effect on the system's overall efficiency. The increase in storage volume has a detrimental effect for small daily load volumes, but a beneficial one when there is a large daily consumption. Solar energy was found to be truly competitive when the conventional fuel being substituted is electricity, and it should not replace diesel oil on pure economic grounds. Large daily load volumes and large collector areas are in general associated with shorter payback periods. Overall, the systems are oversized and are economically suitable for large daily hot water load volumes. (Author)

  7. Modeling patterns of hot water use in households

    Energy Technology Data Exchange (ETDEWEB)

    Lutz, J.D.; Liu, Xiaomin; McMahon, J.E. [and others

    1996-11-01

    This report presents a detailed model of hot water use patterns in individual household. The model improves upon an existing model by including the effects of four conditions that were previously unaccounted for: the absence of a clothes washer; the absence of a dishwasher; a household consisting of seniors only; and a household that does not pay for its own hot water use. Although these four conditions can significantly affect residential hot water use, and have been noted in other studies, this is the first time that they have been incorporated into a detailed model. This model allows detailed evaluation of the impact of potential efficiency standards for water heaters and other market transformation policies. 21 refs., 3 figs., 10 tabs.

  8. Modeling patterns of hot water use in households

    Energy Technology Data Exchange (ETDEWEB)

    Lutz, James D.; Liu, Xiaomin; McMahon, James E.; Dunham, Camilla; Shown, Leslie J.; McCure, Quandra T.

    1996-01-01

    This report presents a detailed model of hot water use patterns in individual households. The model improves upon an existing model by including the effects of four conditions that were previously unaccounted for: the absence of a clothes washer; the absence of a dishwasher; a household consisting of seniors only; and a household that does not pay for its own hot water use. Although these four conditions can significantly affect residential hot water use, and have been noted in other studies, this is the first time that they have been incorporated into a detailed model. This model allows detailed evaluation of the impact of potential efficiency standards for water heaters and other market transformation policies.

  9. Polycarbonate as an Elasto-Plastic Material Model for Simulation of the Microstructure Hot Imprint Process

    Directory of Open Access Journals (Sweden)

    Rokas Šakalys

    2013-08-01

    Full Text Available The thermal imprint process of polymer micro-patterning is widely applied in areas such as manufacturing of optical parts, solar energy, bio-mechanical devices and chemical chips. Polycarbonate (PC, as an amorphous polymer, is often used in thermoforming processes because of its good replication characteristics. In order to obtain replicas of the best quality, the imprint parameters (e.g., pressure, temperature, time, etc. must be determined. Therefore finite element model of the hot imprint process of lamellar periodical microstructure into PC has been created using COMSOL Multiphysics. The mathematical model of the hot imprint process includes three steps: heating, imprinting and demolding. The material properties of amorphous PC strongly depend on the imprint temperature and loading pressure. Polycarbonate was modelled as an elasto-plastic material, since it was analyzed below the glass transition temperature. The hot imprint model was solved using the heat transfer and the solid stress-strain application modes with thermal contact problem between the mold and polycarbonate. It was used for the evaluation of temperature and stress distributions in the polycarbonate during the hot imprint process. The quality of the replica, by means of lands filling ratio, was determined as well.

  10. Models and methods for hot spot safety work

    DEFF Research Database (Denmark)

    Vistisen, Dorte

    2002-01-01

    Despite the fact that millions DKK each year are spent on improving roadsafety in Denmark, funds for traffic safety are limited. It is therefore vital to spend the resources as effectively as possible. This thesis is concerned with the area of traffic safety denoted "hot spot safety work", which...... is the task of improving road safety through alterations of the geometrical and environmental characteristics of the existing road network. The presently applied models and methods in hot spot safety work on the Danish road network were developed about two decades ago, when data was more limited and software...... and statistical methods less developed. The purpose of this thesis is to contribute to improving "State of the art" in Denmark. Basis for the systematic hot spot safety work are the models describing the variation in accident counts on the road network. In the thesis hierarchical models disaggregated on time...

  11. NEW MODEL FOR SOLAR RADIATION ESTIMATION FROM ...

    African Journals Online (AJOL)

    NEW MODEL FOR SOLAR RADIATION ESTIMATION FROM MEASURED AIR TEMPERATURE AND ... Nigerian Journal of Technology ... Solar radiation measurement is not sufficient in Nigeria for various reasons such as maintenance and ...

  12. Smart solar domestic hot water systems. Development and test; Intelligente solvarmeanlaeg. Udvikling og afproevning

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, E.; Knudsen, S.; Furbo, S.; Vejen, N.K.

    2001-07-01

    The purpose of the project described in this report is to develop and test smart solar domestic hot water systems (SDHW systems) where the energy supply from the auxiliary energy supply system is controlled in a flexible way fitted to the hot water consumption in such a way, that the SDHW systems are suitable for large as well as small hot water demands. In a smart SDHW system the auxiliary energy supply system is controlled in a smart way. The auxiliary energy supply system heats up the water in the hot water tank from the top and only the hot water volume needed by the consumers is heated. Further the water is heated immediately before tapping. The control system includes a number of temperature sensors which cover the temperatures in the auxiliary heated volume. Based on these temperatures the energy content in the hot water tank is calculated. Only water heated to a temperature above 50 deg. C contributes to the total energy content in the hot water tank. Furhter the control system includes a timer that only allows the auxiliary energy supply system to be active in certain time periods and only if the energy content in the hot water tank is lower than wanted. In this way the water in the tank is heated immediately before the expected time of tapping and only the hot water volume needed is heated. The report is divided into five main sections. The sections deals with: Developing and testing storage tanks, laboratory test of SDHW systems based on some of the developed storage tanks, validation of simulation programs for smart solar heating systems, optimisation of system design and control strategy and measurements on two smart SDHW systems installed in single family houses. In all the developed hot water tanks, attempt is made to heat the water in the tank from the top of the tank and not as in traditional tanks where the water is heated from the lowest level of the auxiliary energy supply system, normally a helix or a electrical heating element placed in the

  13. Investigation of a solar heating system for space heating and domestic hot water supply for Sol&Træ A.m.b.a

    DEFF Research Database (Denmark)

    Vejen, Niels Kristian

    1999-01-01

    A solar heating system for space heating and domestic hot water supply from "Sol&Træ A.m.b.a." was tested in a laboratory test facility.......A solar heating system for space heating and domestic hot water supply from "Sol&Træ A.m.b.a." was tested in a laboratory test facility....

  14. Investigation of a low flow solar heating system for space heating and domestic hot water supply for Aidt Miljø A/S

    DEFF Research Database (Denmark)

    Vejen, Niels Kristian

    1997-01-01

    A low flow solar heating system for space heating and domestic hot water supply from Aidt Miljø A/Swas tested in a laboratory test facility.......A low flow solar heating system for space heating and domestic hot water supply from Aidt Miljø A/Swas tested in a laboratory test facility....

  15. PWR hot leg natural circulation modeling with MELCOR code

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae Hong; Lee, Jong In [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of)

    1997-12-31

    Previous MELCOR and SCDAP/RELAP5 nodalizations for simulating the counter-current, natural circulation behavior of vapor flow within the RCS hot legs and SG U-tubes when core damage progress can not be applied to the steady state and water-filled conditions during the initial period of accident progression because of the artificially high loss coefficients in the hot legs and SG U-tubes which were chosen from results of COMMIX calculation and the Westinghouse natural circulation experiments in a 1/7-scale facility for simulating steam natural circulation behavior in the vessel and circulation modeling which can be used both for the liquid flow condition at steady state and for the vapor flow condition at the later period of in-vessel core damage. For this, the drag forces resulting from the momentum exchange effects between the two vapor streams in the hot leg was modeled as a pressure drop by pump model. This hot leg natural circulation modeling of MELCOR was able to reproduce similar mass flow rates with those predicted by previous models. 6 refs., 2 figs. (Author)

  16. PWR hot leg natural circulation modeling with MELCOR code

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae Hong; Lee, Jong In [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of)

    1998-12-31

    Previous MELCOR and SCDAP/RELAP5 nodalizations for simulating the counter-current, natural circulation behavior of vapor flow within the RCS hot legs and SG U-tubes when core damage progress can not be applied to the steady state and water-filled conditions during the initial period of accident progression because of the artificially high loss coefficients in the hot legs and SG U-tubes which were chosen from results of COMMIX calculation and the Westinghouse natural circulation experiments in a 1/7-scale facility for simulating steam natural circulation behavior in the vessel and circulation modeling which can be used both for the liquid flow condition at steady state and for the vapor flow condition at the later period of in-vessel core damage. For this, the drag forces resulting from the momentum exchange effects between the two vapor streams in the hot leg was modeled as a pressure drop by pump model. This hot leg natural circulation modeling of MELCOR was able to reproduce similar mass flow rates with those predicted by previous models. 6 refs., 2 figs. (Author)

  17. Modelling and simulations in hot deformation of steels

    International Nuclear Information System (INIS)

    Cabrera, J.M.

    2002-01-01

    Traditionally, hot forming has been employed to provide shape to metals. Nowadays, however, hot working not only produces the desired geometry, but also the mechanical characteristics required. An understanding of the thermomechanical behaviour of metals, and particularly steels, is essential in the simulation and control of the hot forming operations. Moreover, a right prediction of the final properties needs from accurate descriptions of the microstructural features occurring during the shaping step. For this purpose, the determination of constitutive equations describing the stress σ - strain ε relationships at a given strain rate ε, temperature T and initial microstructure, is a useful task. In this sense, computer simulations of hot working processes proportionate a benchmark to engineers and researchers and allow decreasing the cost of developing products and processes. With regard to the prediction of the final microstructure, the simulation of the hot plastic deformation usually gives unsatisfactory results. This is due to the inadequate constitutive equations employed by the conventional and commercial software available to describe the hot flow behaviour. There are scarce models which couple the typical hot working variables (temperature, strain and strain rate) with microstructural characteristics such as grain size. In this review work is presented how the latter limitation can be overcome by using physical-based constitutive equations, some of which have been partially developed by the present authors, where account of the interaction between microstructure and processing variables is taken. Moreover, a practical derivation of the latter expressions on an AISI-304 steel is presented. To conclude, some examples of industrial applications of the latter approach are also presented. Copyright (2002) AD-TECH - International Foundation for the Advancement of Technology Ltd

  18. A revisited standard solar model

    International Nuclear Information System (INIS)

    Casse, M.; Cahen, S.; Doom, C.

    1987-01-01

    Recent models of the Sun, including our own, based on canonical physics and featuring modern reaction rates and radiative opacities are presented. They lead to a presolar helium abundance, in better agreement with the value found in the Orion nebula. Most models predict a neutrino counting rate greater than 6 SNU in the chlorine-argon detector, which is at least 3 times higher than the observed rate. The primordial helium abundance derived from the solar one, on the basis of recent models of helium production from the birth of the Galaxy to the birth of the sun, is significantly higher than the value inferred from observations of extragalactic metal-poor nebulae. This indicates that the stellar production of helium is probably underestimated by the models considered

  19. Hot kinetic model as a guide to improve organic photovoltaic materials.

    Science.gov (United States)

    Sosorev, Andrey Yu; Godovsky, Dmitry Yu; Paraschuk, Dmitry Yu

    2018-01-31

    The modeling of organic solar cells (OSCs) can provide a roadmap for their further improvement. Many OSC models have been proposed in recent years; however, the impact of the key intermediates from photons to electricity-hot charge-transfer (CT) states-on the OSC efficiency is highly ambiguous. In this study, we suggest an analytical kinetic model for OSC that considers a two-step charge generation via hot CT states. This hot kinetic model allowed us to evaluate the impact of different material parameters on the OSC performance: the driving force for charge separation, optical bandgap, charge mobility, geminate recombination rate, thermalization rate, average electron-hole separation distance in the CT state, dielectric permittivity, reorganization energy and charge delocalization. In contrast to a widespread trend of lowering the material bandgap, the model predicts that this approach is only efficient along with improvement of the other material properties. The most promising ways to increase the OSC performance are decreasing the reorganization energy, i.e., an energy change accompanying CT from the donor molecule to the acceptor, increasing the dielectric permittivity and charge delocalization. The model suggests that there are no fundamental limitations that can prevent achieving the OSC efficiency above 20%.

  20. Thermal performance of small solar domestic hot water systems in theory, in the laboratory and in practice

    DEFF Research Database (Denmark)

    Andersen, Elsa

    1998-01-01

    for poor thermal performances of systems tested in practice are given. Based on theoretical calculations the negative impact on the thermal performance, due to a large number of different parameter variations are given. Recommendations for future developments of small solar domestic hot water systems...

  1. The effect of side-chain substitution and hot processing on diketopyrrolopyrrole-based polymers for organic solar cells

    NARCIS (Netherlands)

    Heintges, G.H.L.; Leenaers, P.J.; Janssen, R.A.J.

    2017-01-01

    The effects of cold and hot processing on the performance of polymer-fullerene solar cells are investigated for diketopyrrolopyrrole (DPP) based polymers that were specifically designed and synthesized to exhibit a strong temperature-dependent aggregation in solution. The polymers, consisting of

  2. Solar heating and hot water system installed at Southeast of Saline, Unified School District 306, Mentor, Kansas

    Science.gov (United States)

    1979-01-01

    The solar system, installed in a new building, was designed to provide 52 percent of the estimated annual space heating load and 84 percent of the estimated annual potable hot water requirement. The liquid flat plate collectors are ground-mounted and cover a total area of 5125 square feet. The system will provide supplemental heat for the school's closed-loop water-to-air heat pump system and domestic hot water. The storage medium is water inside steel tanks with a capacity of 11,828 gallons for space heating and 1,600 gallons for domestic hot water. The solar heating facility is described and drawings are presented of the completed system which was declared operational in September 1978, and has functioned successfully since.

  3. Thermal performance parameters estimation of hot box type solar cooker by using artificial neural network

    Energy Technology Data Exchange (ETDEWEB)

    Kurt, Hueseyin; Atik, Kemal; Oezkaymak, Mehmet; Recebli, Ziyaddin [Zonguldak Karaelmas University, Karabuk Technical Education Faculty, 78200 Karabuk (Turkey)

    2008-02-15

    Work to date has shown that Artificial Neural Network (ANN) has not been used for predicting thermal performance parameters of a solar cooker. The objective of this study is to predict thermal performance parameters such as absorber plate, enclosure air and pot water temperatures of the experimentally investigated box type solar cooker by using the ANN. Data set is obtained from the box type solar cooker which was tested under various experimental conditions. A feed-forward neural network based on back propagation algorithm was developed to predict the thermal performance of solar cooker with and without reflector. Mathematical formulations derived from the ANN model are presented for each predicting temperatures. The experimental data set consists of 126 values. These were divided into two groups, of which the 96 values were used for training/learning of the network and the rest of the data (30 values) for testing/validation of the network performance. The performance of the ANN predictions was evaluated by comparing the prediction results with the experimental results. The results showed a good regression analysis with the correlation coefficients in the range of 0.9950-0.9987 and mean relative errors (MREs) in the range of 3.925-7.040% for the test data set. The regression coefficients indicated that the ANN model can successfully be used for the prediction of the thermal performance parameters of a box type solar cooker with a high degree of accuracy. (author)

  4. The effect of payback time on solar hot water systems diffusion: the case of Greece

    International Nuclear Information System (INIS)

    Sidiras, Dimitrios K.; Koukios, Emmanuel G.

    2005-01-01

    The effect of the payback time on the spectacular diffusion of solar hot water systems (SHWS) in Greece was investigated in this work. The time pattern of the diffusion of flat plate solar collectors since its first appearance in 1974 shows that the diffusion rate grew exponentially at first, with the annual sales figure reaching 185,000 m 2 in the mid-80s. A rapid decline of the growth rate, down to the present annual sales level followed. By the year 2000, more than 2,000,000 m 2 of collectors had been installed. The economic behaviour of the main type of users (households and hotels) was found to have undergone two stages: in one of them, 1978-2002, the change of sales is in agreement with a change in economic feasibility, measured by payback time, while in the other, the early growth stage, 1974-1977, the demand grew despite a negative economic trend, obviously because of non-economic factors. The role of tax deduction, which is the most influential incentive, has been rather instrumental in the growth period 1978-1989, but lost its significance thereafter. This incentive has been withdrawn since the beginning of 1993

  5. The effect of payback time on solar hot water systems diffusion: the case of Greece

    International Nuclear Information System (INIS)

    Sidiras, D.K.; Koukios, E.G.

    2005-01-01

    The effect of the payback time on the spectacular diffusion of solar hot water systems (SHWS) in Greece was investigated in this work. The time pattern of the diffusion of flat plate solar collectors since its first appearance in 1974 shows that the diffusion rate grew exponentially at first, with the annual sales figure reaching 185,000 m 2 in the mid-80s. A rapid decline of the growth rate, down to the present annual sales level followed. By the year 2000, more than 2,000,000 m 2 of collectors had been installed. The economic behaviour of the main type of users (households and hotels) was found to have undergone two stages: in one of them, 1978-2002, the change of sales is in agreement with a change in economic feasibility, measured by payback time, while in the other, the early growth stage, 1974-1977, the demand grew despite a negative economic trend, obviously because of non-economic factors. The role of tax deduction, which is the most influential incentive, has been rather instrumental in the growth period 1978-1989, but lost its significance thereafter. This incentive has been withdrawn since the beginning of 1993. [Author

  6. Air-liquid solar collector for solar heating, combined heating and cooling, and hot water subsystems

    Science.gov (United States)

    1978-01-01

    A collection of quarterly reports consisting of the installation and layout design of the air collector system for commercial applications, completion of the preliminary design review, detailed design efforts, and preparation of the verification test plan are given. Performance specifications and performance testing of a prototype model of a two manifold, 144 tube air collector array is presented.

  7. Performance analysis of solar cogeneration system with different integration strategies for potable water and domestic hot water production

    International Nuclear Information System (INIS)

    Uday Kumar, N.T.; Mohan, Gowtham; Martin, Andrew

    2016-01-01

    Highlights: • Solar driven cogeneration system integrating membrane distillation technology is developed. • System utilizes solar thermal energy for the operations without auxiliary heaters. • Three different system integrations are experimentally investigated in UAE. • Economical benefits of solar cogeneration system is also reported. - Abstract: A novel solar thermal cogeneration system featuring the provision of potable water with membrane distillation in combination with domestic hot water supply has been developed and experimentally analyzed. The system integrates evacuated tube collectors, thermal storage, membrane distillation unit, and heat exchangers with the overall goals of maximizing the two outputs while minimizing costs for the given design conditions. Experiments were conducted during one month’s operation at AURAK’s facility in UAE, with average peak global irradiation levels of 650 W/m"2. System performance was determined for three integration strategies, all utilizing brackish water (typical conductivity of 20,000 μs/cm) as a feedstock: Thermal store integration (TSI), which resembles a conventional indirect solar domestic hot water system; Direct solar integration (DSI) connecting collectors directly to the membrane distillation unit without thermal storage; and Direct solar with thermal store integration (DSTSI), a combination of these two approaches. The DSTSI strategy offered the best performance given its operational flexibility. Here the maximum distillate productivity was 43 L/day for a total gross solar collector area of 96 m"2. In terms of simultaneous hot water production, 277 kWh/day was achieved with this configuration. An economic analysis shows that the DSTSI strategy has a payback period of 3.9 years with net cumulative savings of $325,000 during the 20 year system lifetime.

  8. A model for solar constant secular changes

    Science.gov (United States)

    Schatten, Kenneth H.

    1988-01-01

    In this paper, contrast models for solar active region and global photospheric features are used to reproduce the observed Active Cavity Radiometer and Earth Radiation Budget secular trends in reasonably good fashion. A prediction for the next decade of solar constant variations is made using the model. Secular trends in the solar constant obtained from the present model support the view that the Maunder Minimum may be related to the Little Ice Age of the 17th century.

  9. Saphenous Venous Ablation with Hot Contrast in a Canine Model

    International Nuclear Information System (INIS)

    Prasad, Amit; Qian Zhong; Kirsch, David; Eissa, Marna; Narra, Pavan; Lopera, Jorge; Espinoza, Carmen G.; Castaneda, Wifrido

    2008-01-01

    Purpose. To determine the feasibility, efficacy, and safety of thermal ablation of the saphenous vein with hot contrast medium. Methods. Twelve saphenous veins of 6 dogs were percutaneously ablated with hot contrast medium. In all animals, ablation was performed in the vein of one leg, followed by ablation in the contralateral side 1 month later. An occlusion balloon catheter was placed in the infragenicular segment of the saphenous vein via a jugular access to prevent unwanted thermal effects on the non-target segment of the saphenous vein. After inflation of the balloon, 10 ml of hot contrast medium was injected under fluoroscopic control through a sheath placed in the saphenous vein above the ankle. A second 10 ml injection of hot contrast medium was made after 5 min in each vessel. Venographic follow-up of the ablated veins was performed at 1 month (n = 12) and 2 months (n = 6). Results. Follow-up venograms showed that all ablated venous segments were occluded at 1 month. In 6 veins which were followed up to 2 months, 4 (66%) remained occluded, 1 (16%) was partially patent, and the remaining vein (16%) was completely patent. In these latter 2 cases, an inadequate amount of hot contrast was delivered to the lumen due to a closed balloon catheter downstream which did not allow contrast to displace blood within the vessel. Discussion. Hot contrast medium thermal ablation of the saphenous vein appears feasible, safe, and effective in the canine model, provided an adequate amount of embolization agent is used

  10. Modeling pulsations in hot stars with winds

    Energy Technology Data Exchange (ETDEWEB)

    Noels, Arlette; Godart, Melanie [Institut d' Astrophysique et de Geophysique, Liege (Belgium); Dupret, Marc-Antoine [Observatoire de Paris-Meudon, LESIA (France)], E-mail: Arlette.Noels@ulg.ac.be, E-mail: ma.dupret@obspm.fr, E-mail: Melanie.Godart@ulg.ac.be

    2008-10-15

    The interaction pulsation/mass loss takes different aspects. Pulsations can trigger mass loss as in LBVs and Miras; on the other hand, mass loss can modify the driving conditions within the stars. But the most spectacular aspect is the effect on stellar models which, in turn, opens a royal way to asteroseismology to test physical conditions inside massive stars, such as the extent of convective cores or the appearance of new driving mechanisms. We start with a discussion on MS stars and their strange mode instabilities. We then move on to the excitation of the LBV phenomenon. WR stars and the newly observed MOST period in WR123 are discussed in view of the power of asteroseismology. We then turn to B supergiants, in particular HD163899, and show how asteroseismology can really probe convection, semiconvection and mass loss.

  11. Modeling pulsations in hot stars with winds

    International Nuclear Information System (INIS)

    Noels, Arlette; Godart, Melanie; Dupret, Marc-Antoine

    2008-01-01

    The interaction pulsation/mass loss takes different aspects. Pulsations can trigger mass loss as in LBVs and Miras; on the other hand, mass loss can modify the driving conditions within the stars. But the most spectacular aspect is the effect on stellar models which, in turn, opens a royal way to asteroseismology to test physical conditions inside massive stars, such as the extent of convective cores or the appearance of new driving mechanisms. We start with a discussion on MS stars and their strange mode instabilities. We then move on to the excitation of the LBV phenomenon. WR stars and the newly observed MOST period in WR123 are discussed in view of the power of asteroseismology. We then turn to B supergiants, in particular HD163899, and show how asteroseismology can really probe convection, semiconvection and mass loss.

  12. ON THE RELATIONSHIP BETWEEN A HOT-CHANNEL-LIKE SOLAR MAGNETIC FLUX ROPE AND ITS EMBEDDED PROMINENCE

    International Nuclear Information System (INIS)

    Cheng, X.; Ding, M. D.; Zhang, J.; Guo, Y.; Chen, P. F.; Sun, J. Q.; Srivastava, A. K.

    2014-01-01

    A magnetic flux rope (MFR) is a coherent and helical magnetic field structure that has recently been found likely to appear as an elongated hot channel prior to a solar eruption. In this Letter, we investigate the relationship between the hot channel and the associated prominence through analysis of a limb event on 2011 September 12. In the early rise phase, the hot channel was initially cospatial with the prominence. It then quickly expanded, resulting in a separation of the top of the hot channel from that of the prominence. Meanwhile, they both experienced an instantaneous morphology transformation from a Λ shape to a reversed-Y shape and the top of these two structures showed an exponential increase in height. These features are a good indication of the occurrence of kink instability. Moreover, the onset of kink instability is found to coincide in time with the impulsive enhancement of flare emission underneath the hot channel, suggesting that ideal kink instability likely also plays an important role in triggering fast flare reconnection besides initiating the impulsive acceleration of the hot channel and distorting its morphology. We conclude that the hot channel is most likely the MFR system and the prominence only corresponds to the cool materials that are collected in the bottom of the helical field lines of the MFR against gravity

  13. Quantum statistical model for hot dense matter

    International Nuclear Information System (INIS)

    Rukhsana Kouser; Tasneem, G.; Saleem Shahzad, M.; Shafiq-ur-Rehman; Nasim, M.H.; Amjad Ali

    2015-01-01

    In solving numerous applied problems, one needs to know the equation of state, photon absorption coefficient and opacity of substances employed. We present a code for absorption coefficient and opacity calculation based on quantum statistical model. A self-consistent method for the calculation of potential is used. By solving Schrödinger equation with self-consistent potential we find energy spectrum of quantum mechanical system and corresponding wave functions. In addition we find mean occupation numbers of electron states and average charge state of the substance studied. The main processes of interaction of radiation with matter included in our opacity calculation are photon absorption in spectral lines (Bound-bound), photoionization (Bound-free), inverse bremsstrahlung (Free-free), Compton and Thomson scattering. Bound-bound line shape function has contribution from natural, Doppler, fine structure, collisional and stark broadening. To illustrate the main features of the code and its capabilities, calculation of average charge state, absorption coefficient, Rosseland and Planck mean and group opacities of aluminum and iron are presented. Results are satisfactorily compared with the published data. (authors)

  14. Longevity characteristics of flat solar water-heating collectors in hot-water-supply systems. Part 1. Procedure for calculating collector thermal output

    International Nuclear Information System (INIS)

    Avezova, N.R.; Ruziev, O. S.; Suleimanov, Sh. I.; Avezov, R. R.; Vakhidov, A.

    2013-01-01

    A procedure for calculating longevity indices (daily and monthly variations and, hence, annual thermal output) of flat solar water-heating collectors, amount of conditional fuel saved per year by using solar energy, and cost of solar fuel and thermal energy generated in hot-water-supply systems is described. (authors)

  15. Probabilistic Solar Energetic Particle Models

    Science.gov (United States)

    Adams, James H., Jr.; Dietrich, William F.; Xapsos, Michael A.

    2011-01-01

    To plan and design safe and reliable space missions, it is necessary to take into account the effects of the space radiation environment. This is done by setting the goal of achieving safety and reliability with some desired level of confidence. To achieve this goal, a worst-case space radiation environment at the required confidence level must be obtained. Planning and designing then proceeds, taking into account the effects of this worst-case environment. The result will be a mission that is reliable against the effects of the space radiation environment at the desired confidence level. In this paper we will describe progress toward developing a model that provides worst-case space radiation environments at user-specified confidence levels. We will present a model for worst-case event-integrated solar proton environments that provide the worst-case differential proton spectrum. This model is based on data from IMP-8 and GOES spacecraft that provide a data base extending from 1974 to the present. We will discuss extending this work to create worst-case models for peak flux and mission-integrated fluence for protons. We will also describe plans for similar models for helium and heavier ions.

  16. Stellar atmosphere modeling of extremely hot, compact stars

    Science.gov (United States)

    Rauch, Thomas; Ringat, Ellen; Werner, Klaus

    Present X-ray missions like Chandra and XMM-Newton provide excellent spectra of extremely hot white dwarfs, e.g. burst spectra of novae. Their analysis requires adequate NLTE model atmospheres. The Tuebingen Non-LTE Model-Atmosphere Package (TMAP) can calculate such model at-mospheres and spectral energy distributions at a high level of sophistication. We present a new grid of models that is calculated in the parameter range of novae and supersoft X-ray sources and show examples of their application.

  17. A revisited standard solar model

    International Nuclear Information System (INIS)

    Casse, M.; Cahen, S.; Doom, C.

    1985-09-01

    Recent models of the Sun, including our own, based on canonical physics and featuring modern reaction rates and radiative opacities are presented. They lead to a presolar helium abundance of approximately 0.28 by mass, at variance with the value of 0.25 proposed by Bahcall et al. (1982, 1985), but in better agreement with the value found in the Orion nebula. Most models predict a neutrino counting rate greater than 6 SNU in the chlorine-argon detector, which is at least 3 times higher than the observed rate. The primordial helium abundance derived from the solar one, on the basis of recent models of helium production from the birth of the Galaxy to the birth of the sun, Ysub(P) approximately 0.26, is significantly higher than the value inferred from observations of extragalactic metal-poor nebulae (Y approximately 0.23). This indicates that the stellar production of helium is probably underestimated by the models considered

  18. Application of solar energy to the supply of industrial process hot water. Aerotherm final report, 77-235. [Can washing in Campbell Soup plant

    Energy Technology Data Exchange (ETDEWEB)

    None

    1977-01-01

    The objectives of the Solar Industrial Process Hot Water Program are to design, test, and evaluate the application of solar energy to the generation and supply of industrial process hot water, and to provide an assessment of the economic and resource benefits to be gained. Other objectives are to stimulate and give impetus to the use of solar energy for supplying significant amounts of industrial process heat requirements. The plant selected for the design of a solar industrial process hot water system was the Campbell Soup facility in Sacramento, California. The total hot water demand for this plant varies between 500 and 800 gpm during regular production shifts, and hits a peak of over 1,000 gpm for approximately one hour during the cleanup shift. Most of the hot water is heated in the boiler room by a combination of waste heat recovery and low pressure (5 psi) steam-water heat exchangers. The hot water emerges from the boiler room at a temperature between 160/sup 0/F and 180/sup 0/F and is transported to the various process areas. Booster heaters in the process areas then use low pressure (5 psi) or medium pressure (20 psi) steam to raise the temperature of the water to the level required for each process. Hot water is used in several processes at the Campbell Soup plant, but the can washing process was selected to demonstrate the feasibility of a solar hot water system. A detailed design and economic analysis of the system is given. (WHK)

  19. Impact on a utility, utility customers and the environment of an ensemble of solar domestic hot water systems

    International Nuclear Information System (INIS)

    Cragan, K.E.; Klein, S.A.; Beckman, W.A.

    1995-01-01

    The benefits of the installation of a large number of solar domestic hot water (SDHW) systems are identified and quantified. The benefits of SDHW systems include reduced energy use, reduced electrical demand, and reduced pollution. The avoided emissions, capacity contribution, energy and demand savings were evaluated using the power generation schedules, emissions data and annual hourly load profiles from a Wisconsin utility. It is shown that each six square meter solar water heater system can save annually: 3,560 kWh of energy, 0.66 kW of peak demand, and over four tons of pollution

  20. A HOT GAP AROUND JUPITER'S ORBIT IN THE SOLAR NEBULA

    Energy Technology Data Exchange (ETDEWEB)

    Turner, N. J.; Choukroun, M.; Castillo-Rogez, J.; Bryden, G., E-mail: neal.turner@jpl.nasa.gov [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2012-04-01

    The Sun was an order of magnitude more luminous during the first few hundred thousand years of its existence, due in part to the gravitational energy released by material accreting from the solar nebula. If Jupiter was already near its present mass, the planet's tides opened an optically thin gap in the nebula. Using Monte Carlo radiative transfer calculations, we show that sunlight absorbed by the nebula and re-radiated into the gap raised temperatures well above the sublimation threshold for water ice, with potentially drastic consequences for the icy bodies in Jupiter's feeding zone. Bodies up to a meter in size were vaporized within a single orbit if the planet was near its present location during this early epoch. Dust particles lost their ice mantles, and planetesimals were partially to fully devolatilized, depending on their size. Scenarios in which Jupiter formed promptly, such as those involving a gravitational instability of the massive early nebula, must cope with the high temperatures. Enriching Jupiter in the noble gases through delivery trapped in clathrate hydrates will be more difficult, but might be achieved by either forming the planet much farther from the star or capturing planetesimals at later epochs. The hot gap resulting from an early origin for Jupiter also would affect the surface compositions of any primordial Trojan asteroids.

  1. A solar cooling system for greenhouse food production in hot climates

    Energy Technology Data Exchange (ETDEWEB)

    Davies, P.A. [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2005-12-01

    This study is motivated by the difficulty of cultivating crops in very hot countries and by the tendency for some such countries to become dependent on imported food. Liquid desiccation with solar regeneration is considered as maintained at or above room temperature, and this was confirgreenhouses. Previous studies demonstrated the technical feasibility of the desiccation-evaporation process, but mainly in the context of human dwellings. In the proposed cycle, the air is dried prior to entering the evaporative cooler. This lowers the wet-bulb temperature of the air. The cooling is assisted by using the regenerator to partially shade the greenhouse. The heat of desiccation is transferred and rejected at the outlet of the greenhouse. The cycle is analysed and results given for the climate of the The Gulf, based on weather data from Abu Dhabi. Taking examples of a temperate crop (lettuce), a tropical crop (tomato) and a tropical crop resistant to high temperatures (cucumber) we estimate the extension in growing seasons relative to (i) a greenhouse with simple fan ventilation (ii) a greenhouse with conventional evaporative cooling. Compared to option (ii), the proposed system lowers summers maximum temperatures by 5{sup o}C. This will extend the optimum season for lettuce cultivation from 3 to 6 months of the year and, for tomato and cucumber, from 7 months to the whole year. (author)

  2. Solar Power Potential of Tanzania: Identifying CSP and PV Hot Spots through a GIS Multicriteria Decision Making Analysis

    DEFF Research Database (Denmark)

    Aly, Ahmed; Jensen, Steen Solvang; Pedersen, Anders Branth

    2017-01-01

    More than one billion people are still living without access to electricity today. More than half of them are living in Sub-Saharan Africa. There is a noticeable shortage of energy related information in Africa, especially for renewable energies. Due to lacking studies and researches on integrating...... renewable energy technologies, the Tanzanian official generation expansion plan till 2035 showed high dependency on fossil fuel and a negligible role of renewables other than large hydropower. This study investigates the spatial suitability for large-scale solar power installations in Tanzania through using...... technology-specific suitability map categorizes all the non-excluded areas into most suitable, suitable, moderately suitable, and least suitable areas. The study also suggests four hot spots (i.e. specific recommended locations) for Concentrated Solar Power (CSP) installations and four hot spots...

  3. Solar Hot Air Balloons: A Low Cost, Multi-hour Flight System for Lightweight Scientific Instrumentation Packages

    Science.gov (United States)

    Bowman, D. C.; Albert, S.; Dexheimer, D.; Murphy, S.; Mullen, M.

    2017-12-01

    Existing scientific ballooning solutions for multi hour flights in the upper troposphere/lower stratosphere are expensive and/or technically challenging. In contrast, solar hot air balloons are inexpensive and simple to construct. These balloons, which rely solely on sunlight striking a darkened envelope, can deliver payloads to 22 km altitude and maintain level flight until sunset. We describe an experimental campaign in which five solar hot air balloons launched in 45 minutes created a free flying infrasound (low frequency sound) microphone network that remained in the air for over 12 hours. We discuss the balloons' trajectory, maximum altitude, and stability as well as present results from the infrasound observations. We assess the performance and limitations of this design for lightweight atmospheric instrumentation deployments that require multi-hour flight times. Finally, we address the possibilities of multi day flights during the polar summer and on other planets.

  4. Retrofitted Solar Domestic Hot Water Systems for Swedish Single-Family Houses—Evaluation of a Prototype and Life-Cycle Cost Analysis

    Directory of Open Access Journals (Sweden)

    Luis Ricardo Bernardo

    2016-11-01

    Full Text Available According to recent technology road maps, system cost reductions and development of standardised plug-and-function systems are some of the most important goals for solar heating technology development. Retrofitting hot water boilers in single-family houses when installing solar collectors has the potential to significantly reduce both material and installation costs. Previous studies have investigated such retrofitting, using theoretical simulations and laboratory tests, but no actual installations were made and tested in practice. This article describes the installation, measured performance and cost effectiveness of a retrofitting solution that converts existing domestic hot water heaters to a solar domestic hot water system. The measured performance is characterised by the monthly and annual solar fractions. The cost effectiveness is evaluated by a life-cycle cost analysis, comparing the retrofitted system to a conventional solar domestic hot water system and the case without any solar heating system. Measurements showed that approximately 50% of the 5000 kWh/year of domestic hot water consumption was saved by the retrofitted system in south Sweden. Such savings are in agreement with previous estimations and are comparable to the energy savings when using a conventional solar domestic hot water system. The life-cycle cost analysis showed that, according to the assumptions and given climate, the return on investment of the retrofitted system is approximately 17 years, while a conventional system does not reach profitability during its lifetime of 25 years.

  5. A library of ATMO forward model transmission spectra for hot Jupiter exoplanets

    Science.gov (United States)

    Goyal, Jayesh M.; Mayne, Nathan; Sing, David K.; Drummond, Benjamin; Tremblin, Pascal; Amundsen, David S.; Evans, Thomas; Carter, Aarynn L.; Spake, Jessica; Baraffe, Isabelle; Nikolov, Nikolay; Manners, James; Chabrier, Gilles; Hebrard, Eric

    2018-03-01

    We present a grid of forward model transmission spectra, adopting an isothermal temperature-pressure profile, alongside corresponding equilibrium chemical abundances for 117 observationally significant hot exoplanets (equilibrium temperatures of 547-2710 K). This model grid has been developed using a 1D radiative-convective-chemical equilibrium model termed ATMO, with up-to-date high-temperature opacities. We present an interpretation of observations of 10 exoplanets, including best-fitting parameters and χ2 maps. In agreement with previous works, we find a continuum from clear to hazy/cloudy atmospheres for this sample of hot Jupiters. The data for all the 10 planets are consistent with subsolar to solar C/O ratio, 0.005 to 10 times solar metallicity and water rather than methane-dominated infrared spectra. We then explore the range of simulated atmospheric spectra for different exoplanets, based on characteristics such as temperature, metallicity, C/O ratio, haziness and cloudiness. We find a transition value for the metallicity between 10 and 50 times solar, which leads to substantial changes in the transmission spectra. We also find a transition value of C/O ratio, from water to carbon species dominated infrared spectra, as found by previous works, revealing a temperature dependence of this transition point ranging from ˜0.56 to ˜1-1.3 for equilibrium temperatures from ˜900 to ˜2600 K. We highlight the potential of the spectral features of HCN and C2H2 to constrain the metallicities and C/O ratios of planets, using James Webb Space Telescope (JWST) observations. Finally, our entire grid (˜460 000 simulations) is publicly available and can be used directly with the JWST simulator PandExo for planning observations.

  6. A Library of ATMO Forward Model Transmission Spectra for Hot Jupiter Exoplanets

    Science.gov (United States)

    Goyal, Jayesh M.; Mayne, Nathan; Sing, David K.; Drummond, Benjamin; Tremblin, Pascal; Amundsen, David S.; Evans, Thomas; Carter, Aarynn L.; Spake, Jessica; Baraffe, Isabelle; hide

    2017-01-01

    We present a grid of forward model transmission spectra, adopting an isothermal temperature-pressure profile, alongside corresponding equilibrium chemical abundances for 117 observationally significant hot exoplanets (equilibrium temperatures of 547-2710 K). This model grid has been developed using a 1D radiative-convective-chemical equilibrium model termed ATMO, with up-to-date high-temperature opacities. We present an interpretation of observations of 10 exoplanets, including best-fitting parameters and X(exp 2) maps. In agreement with previous works, we find a continuum from clear to hazy/cloudy atmospheres for this sample of hot Jupiters. The data for all the 10 planets are consistent with subsolar to solar C/O ratio, 0.005 to 10 times solar metallicity and water rather than methane-dominated infrared spectra. We then explore the range of simulated atmospheric spectra for different exoplanets, based on characteristics such as temperature, metallicity, C/O ratio, haziness and cloudiness. We find a transition value for the metallicity between 10 and 50 times solar, which leads to substantial changes in the transmission spectra. We also find a transition value of C/O ratio, from water to carbon species dominated infrared spectra, as found by previous works, revealing a temperature dependence of this transition point ranging from approximately 0.56 to approximately 1-1.3 for equilibrium temperatures from approximately 900 to approximately 2600 K. We highlight the potential of the spectral features of HCN and C2H2 to constrain the metallicities and C/O ratios of planets, using James Webb Space Telescope (JWST) observations. Finally, our entire grid (approximately 460 000 simulations) is publicly available and can be used directly with the JWST simulator PandExo for planning observations.

  7. A method of exploration of the atmosphere of Titan. [hot air balloon heated by solar radiation or planetary thermal flux

    Science.gov (United States)

    Blamont, J.

    1978-01-01

    A hot-air balloon, with the air heated by natural sources, is described. Buoyancy is accomplished by either solar heating or by utilizing the IR thermal flux of the planet to heat the gas in the balloon. Altitude control is provided by a valve which is opened and closed by a barometer. The balloon is made of an organic material which has to absorb radiant energy and to emit as little as possible.

  8. A model for hot electron phenomena: Theory and general results

    International Nuclear Information System (INIS)

    Carrillo, J.L.; Rodriquez, M.A.

    1988-10-01

    We propose a model for the description of the hot electron phenomena in semiconductors. Based on this model we are able to reproduce accurately the main characteristics observed in experiments of electric field transport, optical absorption, steady state photoluminescence and relaxation process. Our theory does not contain free nor adjustable parameters, it is very fast computerwise, and incorporates the main collision mechanisms including screening and phonon heating effects. Our description on a set of nonlinear rate equations in which the interactions are represented by coupling coefficients or effective frequencies. We calculate three coefficients from the characteristic constants and the band structure of the material. (author). 22 refs, 5 figs, 1 tab

  9. Microstructural modelling and lubrication study during zirconium alloy hot extrusion

    International Nuclear Information System (INIS)

    Gaudout, B.

    2009-01-01

    Using torsion tests (with strain rate jumps) and an experimental hot mini-extrusion apparatus, several samples zirconium alloy have been deformed: Zircaloy-4 (high α range) and Zr-1Nb (α + β domain). The fragmentation of the microstructure and post-dynamic grain growth have been examined. The main difference between these two alloys is that Zr-1Nb does not show grain growth during a heat treatment within the α + β domain after hot deformation. The recrystallization volume fraction has been measured on extruded samples with or without heat treatment. These rheological and microstructural data have been used to determine the parameters of a microstructural model including: a work-hardening model (Laaasraoui/Jonas), a continuous dynamic recrystallization model (Gourdet/Montheillet) and a grain growth model. This model leads to a good prediction of recrystallization volume fraction for Zircaloy-4 extrusion. However, the Zr-1Nb model cannot be validated because of the difficulty to observe deformed microstructures. Extrusion process is lubricated with a solid film. Trapping tests show that this lubricant is thermoviscoplastic. Friction along the container and several observations show the lubrication is not realized by a continuous film. Indeed, the heterogeneousness of deformation of these alloys causes a rupture of the lubricant film. Experiments and numerical simulations show that the radial gradient of axial displacement is affected by friction but also by stress softening of the alloys. (author)

  10. Prospects for jointly using solar and wind energy for heat supply and hot water supply to private houses under the conditions of Baku

    International Nuclear Information System (INIS)

    Salamov, O. M.; Aliev, F. F.

    2013-01-01

    This paper analyzes the discovery of the potential for jointly using solar and wind energy for heat supply (HS) and hot water supply (HWS) to a one-family private house located in the Apsheron Peninsula. (authors)

  11. THERMAL RESPONSE OF A SOLAR-LIKE ATMOSPHERE TO AN ELECTRON BEAM FROM A HOT JUPITER: A NUMERICAL EXPERIMENT

    International Nuclear Information System (INIS)

    Gu, P.-G.; Suzuki, Takeru K.

    2009-01-01

    We investigate the thermal response of the atmosphere of a solar-type star to an electron beam injected from a hot Jupiter by performing a one-dimensional MHD numerical experiment with nonlinear wave dissipation, radiative cooling, and thermal conduction. In our experiment, the stellar atmosphere is non-rotating and is modeled as a one-dimensional open flux tube expanding super-radially from the stellar photosphere to the planet. An electron beam is assumed to be generated from the reconnection site of the planet's magnetosphere. The effects of the electron beam are then implemented in our simulation as dissipation of the beam momentum and energy at the base of the corona where the Coulomb collisions become effective. When the sufficient energy is supplied by the electron beam, a warm region forms in the chromosphere. This warm region greatly enhances the radiative fluxes corresponding to the temperature of the chromosphere and transition region. The warm region can also intermittently contribute to the radiative flux associated with the coronal temperature due to the thermal instability. However, owing to the small area of the heating spot, the total luminosity of the beam-induced chromospheric radiation is several orders of magnitude smaller than the observed Ca II emissions from HD 179949.

  12. Investigation of a heat storage for a solar heating system for combined space heating and domestic hot water supply for homeowner´s association "Bakken"

    DEFF Research Database (Denmark)

    Vejen, Niels Kristian

    1998-01-01

    A heat storage for a solar heating system for combined space heating and domestic hot water supply was tested in a laboratory test facility.The heat storage consist of a mantle tank with water for the heating system and of a hot water tank, which by means of thermosyphoning is heated by the water...

  13. Analytical models for the rewetting of hot surfaces

    International Nuclear Information System (INIS)

    Olek, S.

    1988-10-01

    Some aspects concerning analytical models for the rewetting of hot surface are discussed. These include the problems with applying various forms of boundary conditions, compatibility of boundary conditions with the physics of the rewetting problems, recent analytical models, the use of the separation of variables method versus the Wiener-Hopf technique, and the use of transformations. The report includes an updated list of rewetting models as well as benchmark solutions in tabular form for several models. It should be emphasized that this report is not meant to cover the topic of rewetting models. It merely discusses some points which are less commonly referred to in the literature. 93 refs., 3 figs., 22 tabs

  14. Search for solar axions by the CERN axion solar telescope with 3He buffer gas: closing the hot dark matter gap.

    Science.gov (United States)

    Arik, M; Aune, S; Barth, K; Belov, A; Borghi, S; Bräuninger, H; Cantatore, G; Carmona, J M; Cetin, S A; Collar, J I; Da Riva, E; Dafni, T; Davenport, M; Eleftheriadis, C; Elias, N; Fanourakis, G; Ferrer-Ribas, E; Friedrich, P; Galán, J; García, J A; Gardikiotis, A; Garza, J G; Gazis, E N; Geralis, T; Georgiopoulou, E; Giomataris, I; Gninenko, S; Gómez, H; Gómez Marzoa, M; Gruber, E; Guthörl, T; Hartmann, R; Hauf, S; Haug, F; Hasinoff, M D; Hoffmann, D H H; Iguaz, F J; Irastorza, I G; Jacoby, J; Jakovčić, K; Karuza, M; Königsmann, K; Kotthaus, R; Krčmar, M; Kuster, M; Lakić, B; Lang, P M; Laurent, J M; Liolios, A; Ljubičić, A; Luzón, G; Neff, S; Niinikoski, T; Nordt, A; Papaevangelou, T; Pivovaroff, M J; Raffelt, G; Riege, H; Rodríguez, A; Rosu, M; Ruz, J; Savvidis, I; Shilon, I; Silva, P S; Solanki, S K; Stewart, L; Tomás, A; Tsagri, M; van Bibber, K; Vafeiadis, T; Villar, J; Vogel, J K; Yildiz, S C; Zioutas, K

    2014-03-07

    The CERN Axion Solar Telescope has finished its search for solar axions with (3)He buffer gas, covering the search range 0.64 eV ≲ ma ≲ 1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of gaγ ≲ 3.3 × 10(-10)  GeV(-1) at 95% C.L., with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of gaγ, for example by the currently discussed next generation helioscope International AXion Observatory.

  15. Search for Solar Axions by the CERN Axion Solar Telescope with 3 He Buffer Gas: Closing the Hot Dark Matter Gap

    CERN Document Server

    Arik, M.; Barth, K.; Belov, A.; Borghi, S.; Bräuninger, H.; Cantatore, G.; Carmona, J.M.; Cetin, S.A.; Collar, J.I.; Da Riva, E.; Dafni, T.; Davenport, M.; Eleftheriadis, C.; Elias, N.; Fanourakis, G.; Ferrer-Ribas, E.; Friedrich, P.; Galán, J.; García, J.A.; Gardikiotis, A.; Garza, J.G.; Gazis, E.N.; Geralis, T.; Georgiopoulou, E.; Giomataris, I.; Gninenko, S.; Gómez, H.; Gómez Marzoa, M.; Gruber, E.; Guthörl, T.; Hartmann, R.; Hauf, S.; Haug, F.; Hasinoff, M.D.; Hoffmann, D.H.H.; Iguaz, F.J.; Irastorza, I.G.; Jacoby, J.; Jakovčić, K.; Karuza, M.; Königsmann, K.; Kotthaus, R.; Krčmar, M.; Kuster, M.; Lakić, B.; Lang, P.M.; Laurent, J.M.; Liolios, A.; Ljubičić, A.; Lozza, V.; Luzón, G.; Neff, S.; Niinikoski, T.; Nordt, A.; Papaevangelou, T.; Pivovaroff, M.J.; Raffelt, G.; Riege, H.; Rodríguez, A.; Rosu, M.; Ruz, J.; Savvidis, I.; Shilon, I.; Silva, P.S.; Solanki, S.K.; Stewart, L.; Tomás, A.; Tsagri, M.; van Bibber, K.; Vafeiadis, T.; Villar, J.; Vogel, J.K.; Yildiz, S.C.; Zioutas, K.

    2014-01-01

    The CERN Axion Solar Telescope (CAST) has finished its search for solar axions with 3^He buffer gas, covering the search range 0.64 eV < m_a <1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess X-rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g_ag < 3.3 x 10^{-10} GeV^{-1} at 95% CL, with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of g_a, for example by the currently discussed next generation helioscope IAXO.

  16. Search for Solar Axions by the CERN Axion Solar Telescope with He3 Buffer Gas: Closing the Hot Dark Matter Gap

    Science.gov (United States)

    Arik, M.; Aune, S.; Barth, K.; Belov, A.; Borghi, S.; Bräuninger, H.; Cantatore, G.; Carmona, J. M.; Cetin, S. A.; Collar, J. I.; Da Riva, E.; Dafni, T.; Davenport, M.; Eleftheriadis, C.; Elias, N.; Fanourakis, G.; Ferrer-Ribas, E.; Friedrich, P.; Galán, J.; García, J. A.; Gardikiotis, A.; Garza, J. G.; Gazis, E. N.; Geralis, T.; Georgiopoulou, E.; Giomataris, I.; Gninenko, S.; Gómez, H.; Gómez Marzoa, M.; Gruber, E.; Guthörl, T.; Hartmann, R.; Hauf, S.; Haug, F.; Hasinoff, M. D.; Hoffmann, D. H. H.; Iguaz, F. J.; Irastorza, I. G.; Jacoby, J.; Jakovčić, K.; Karuza, M.; Königsmann, K.; Kotthaus, R.; Krčmar, M.; Kuster, M.; Lakić, B.; Lang, P. M.; Laurent, J. M.; Liolios, A.; Ljubičić, A.; Luzón, G.; Neff, S.; Niinikoski, T.; Nordt, A.; Papaevangelou, T.; Pivovaroff, M. J.; Raffelt, G.; Riege, H.; Rodríguez, A.; Rosu, M.; Ruz, J.; Savvidis, I.; Shilon, I.; Silva, P. S.; Solanki, S. K.; Stewart, L.; Tomás, A.; Tsagri, M.; van Bibber, K.; Vafeiadis, T.; Villar, J.; Vogel, J. K.; Yildiz, S. C.; Zioutas, K.; CAST Collaboration

    2014-03-01

    The CERN Axion Solar Telescope has finished its search for solar axions with He3 buffer gas, covering the search range 0.64 eV≲ma≲1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of gaγ≲3.3×10-10 GeV-1 at 95% C.L., with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of gaγ, for example by the currently discussed next generation helioscope International AXion Observatory.

  17. The impact of silicon solar cell architecture and cell interconnection on energy yield in hot & sunny climates

    KAUST Repository

    Haschke, Jan

    2017-03-23

    Extensive knowledge of the dependence of solar cell and module performance on temperature and irradiance is essential for their optimal application in the field. Here we study such dependencies in the most common high-efficiency silicon solar cell architectures, including so-called Aluminum back-surface-field (BSF), passivated emitter and rear cell (PERC), passivated emitter rear totally diffused (PERT), and silicon heterojunction (SHJ) solar cells. We compare measured temperature coefficients (TC) of the different electrical parameters with values collected from commercial module data sheets. While similar TC values of the open-circuit voltage and the short circuit current density are obtained for cells and modules of a given technology, we systematically find that the TC under maximum power-point (MPP) conditions is lower in the modules. We attribute this discrepancy to additional series resistance in the modules from solar cell interconnections. This detrimental effect can be reduced by using a cell design that exhibits a high characteristic load resistance (defined by its voltage-over-current ratio at MPP), such as the SHJ architecture. We calculate the energy yield for moderate and hot climate conditions for each cell architecture, taking into account ohmic cell-to-module losses caused by cell interconnections. Our calculations allow us to conclude that maximizing energy production in hot and sunny environments requires not only a high open-circuit voltage, but also a minimal series-to-load-resistance ratio.

  18. Residence time modeling of hot melt extrusion processes.

    Science.gov (United States)

    Reitz, Elena; Podhaisky, Helmut; Ely, David; Thommes, Markus

    2013-11-01

    The hot melt extrusion process is a widespread technique to mix viscous melts. The residence time of material in the process frequently determines the product properties. An experimental setup and a corresponding mathematical model were developed to evaluate residence time and residence time distribution in twin screw extrusion processes. The extrusion process was modeled as the convolution of a mass transport process described by a Gaussian probability function, and a mixing process represented by an exponential function. The residence time of the extrusion process was determined by introducing a tracer at the extruder inlet and measuring the tracer concentration at the die. These concentrations were fitted to the residence time model, and an adequate correlation was found. Different parameters were derived to characterize the extrusion process including the dead time, the apparent mixing volume, and a transport related axial mixing. A 2(3) design of experiments was performed to evaluate the effect of powder feed rate, screw speed, and melt viscosity of the material on the residence time. All three parameters affect the residence time of material in the extruder. In conclusion, a residence time model was developed to interpret experimental data and to get insights into the hot melt extrusion process. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. A collisional-radiative average atom model for hot plasmas

    International Nuclear Information System (INIS)

    Rozsnyai, B.F.

    1996-01-01

    A collisional-radiative 'average atom' (AA) model is presented for the calculation of opacities of hot plasmas not in the condition of local thermodynamic equilibrium (LTE). The electron impact and radiative rate constants are calculated using the dipole oscillator strengths of the average atom. A key element of the model is the photon escape probability which at present is calculated for a semi infinite slab. The Fermi statistics renders the rate equation for the AA level occupancies nonlinear, which requires iterations until the steady state. AA level occupancies are found. Detailed electronic configurations are built into the model after the self-consistent non-LTE AA state is found. The model shows a continuous transition from the non-LTE to the LTE state depending on the optical thickness of the plasma. 22 refs., 13 figs., 1 tab

  20. Steady state model for the thermal regimes of shells of airships and hot air balloons

    Science.gov (United States)

    Luchev, Oleg A.

    1992-10-01

    A steady state model of the temperature regime of airships and hot air balloons shells is developed. The model includes three governing equations: the equation of the temperature field of airships or balloons shell, the integral equation for the radiative fluxes on the internal surface of the shell, and the integral equation for the natural convective heat exchange between the shell and the internal gas. In the model the following radiative fluxes on the shell external surface are considered: the direct and the earth reflected solar radiation, the diffuse solar radiation, the infrared radiation of the earth surface and that of the atmosphere. For the calculations of the infrared external radiation the model of the plane layer of the atmosphere is used. The convective heat transfer on the external surface of the shell is considered for the cases of the forced and the natural convection. To solve the mentioned set of the equations the numerical iterative procedure is developed. The model and the numerical procedure are used for the simulation study of the temperature fields of an airship shell under the forced and the natural convective heat transfer.

  1. Detailed Physical Trough Model for NREL's Solar Advisor Model: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, M. J.; Blair, N.; Dobos, A.

    2010-10-01

    Solar Advisor Model (SAM) is a free software package made available by the National Renewable Energy Laboratory (NREL), Sandia National Laboratory, and the US Department of Energy. SAM contains hourly system performance and economic models for concentrating solar power (CSP) systems, photovoltaic, solar hot-water, and generic fuel-use technologies. Versions of SAM prior to 2010 included only the parabolic trough model based on Excelergy. This model uses top-level empirical performance curves to characterize plant behavior, and thus is limited in predictive capability for new technologies or component configurations. To address this and other functionality challenges, a new trough model; derived from physical first principles was commissioned to supplement the Excelergy-based empirical model. This new 'physical model' approaches the task of characterizing the performance of the whole parabolic trough plant by replacing empirical curve-fit relationships with more detailed calculations where practical. The resulting model matches the annual performance of the SAM empirical model (which has been previously verified with plant data) while maintaining run-times compatible with parametric analysis, adding additional flexibility in modeled system configurations, and providing more detailed performance calculations in the solar field, power block, piping, and storage subsystems.

  2. Validation of a simulation method for forced circulation type of solar domestic hot water heating systems; Kyosei junkangata taiyonetsu kyuto system simulation hoho no kensho

    Energy Technology Data Exchange (ETDEWEB)

    Sato, M; Udagawa, M [Kogakuin University, Tokyo (Japan); Matsumoto, T [Yazaki Corp., Tokyo (Japan)

    1996-10-27

    Simulation of solar hot water systems using element model was conducted, in which computation of the convergence of apparatus characteristic values was performed every hour. For each apparatus, the outlet temperature was made a function of the inlet temperature on the basis of the heat balance, from which a simultaneous equation was derived and then solved for the determination of the outlet temperature for the computation of the quantity of heat collected by each apparatus. The actually measured system comprises a planar solar collector, heat storage tank, and heat collector piping. The measurement involved a direct heat collecting system with the medium running from the heat storage tank bottom layer, through the solar collector, and then back to the heat storage tank third layer, and an indirect heat collector system with a heat exchanger provided at the heat storage tank bottom layer. There was no substantial difference between the direct type and the indirect type with respect to the solar collector inlet and outlet temperatures, quantity of heat collected, and the fluctuation in heat storage tank inside temperature distribution relative to time. Difference occurred between the two in tank water temperature distribution, however, when water was extracted in great volume at a time. The quantity of the heat collected by each of the two and the daily integration of the same differed but a little from computed values. 4 refs., 6 figs., 4 tabs.

  3. SOLCOST. Solar Hot Water Handbook. A Simplified Design Method for Sizing and Costing Residential and Commercial Solar Service Hot Water Systems. Second Edition.

    Science.gov (United States)

    Energy Research and Development Administration, Washington, DC. Div. of Solar Energy.

    This pamphlet offers a preview of information services available from Solcost, a research and development project. The first section explains that Solcost calculates system and costs performance for solar heated and cooled new and retrofit constructions, such as residential buildings and single zone commercial buildings. For a typical analysis,…

  4. Biophysical model of prokaryotic diversity in geothermal hot springs.

    Science.gov (United States)

    Klales, Anna; Duncan, James; Nett, Elizabeth Janus; Kane, Suzanne Amador

    2012-02-01

    Recent studies of photosynthetic bacteria living in geothermal hot spring environments have revealed surprisingly complex ecosystems with an unexpected level of genetic diversity. One case of particular interest involves the distribution along hot spring thermal gradients of genetically distinct bacterial strains that differ in their preferred temperatures for reproduction and photosynthesis. In such systems, a single variable, temperature, defines the relevant environmental variation. In spite of this, each region along the thermal gradient exhibits multiple strains of photosynthetic bacteria adapted to several distinct thermal optima, rather than a single thermal strain adapted to the local environmental temperature. Here we analyze microbiology data from several ecological studies to show that the thermal distribution data exhibit several universal features independent of location and specific bacterial strain. These include the distribution of optimal temperatures of different thermal strains and the functional dependence of the net population density on temperature. We present a simple population dynamics model of these systems that is highly constrained by biophysical data and by physical features of the environment. This model can explain in detail the observed thermal population distributions, as well as certain features of population dynamics observed in laboratory studies of the same organisms. © 2012 American Physical Society

  5. Design of nanophotonic, hot-electron solar-blind ultraviolet detectors with a metal-oxide-semiconductor structure

    International Nuclear Information System (INIS)

    Wang, Zhiyuan; Wang, Xiaoxin; Liu, Jifeng

    2014-01-01

    Solar-blind ultraviolet (UV) detection refers to photon detection specifically in the wavelength range of 200 nm–320 nm. Without background noises from solar radiation, it has broad applications from homeland security to environmental monitoring. The most commonly used solid state devices for this application are wide band gap (WBG) semiconductor photodetectors (Eg > 3.5 eV). However, WBG semiconductors are difficult to grow and integrate with Si readout integrated circuits (ROICs). In this paper, we design a nanophotonic metal-oxide-semiconductor structure on Si for solar-blind UV detectors. Instead of using semiconductors as the active absorber, we use Sn nano-grating structures to absorb UV photons and generate hot electrons for internal photoemission across the Sn/SiO 2 interfacial barrier, thereby generating photocurrent between the metal and the n-type Si region upon UV excitation. Moreover, the transported hot electron has an excess kinetic energy >3 eV, large enough to induce impact ionization and generate another free electron in the conduction band of n-Si. This process doubles the quantum efficiency. On the other hand, the large metal/oxide interfacial energy barrier (>3.5 eV) also enables solar-blind UV detection by blocking the less energetic electrons excited by visible photons. With optimized design, ∼75% UV absorption and hot electron excitation can be achieved within the mean free path of ∼20 nm from the metal/oxide interface. This feature greatly enhances hot electron transport across the interfacial barrier to generate photocurrent. The simple geometry of the Sn nano-gratings and the MOS structure make it easy to fabricate and integrate with Si ROICs compared to existing solar-blind UV detection schemes. The presented device structure also breaks through the conventional notion that photon absorption by metal is always a loss in solid-state photodetectors, and it can potentially be extended to other active metal photonic devices. (paper)

  6. Tandem solar cells deposited using hot-wire chemical vapor deposition

    NARCIS (Netherlands)

    Veen, M.K. van

    2003-01-01

    In this thesis, the application of the hot-wire chemical vapor deposition (HWCVD) technique for the deposition of silicon thin films is described. The HWCVD technique is based on the dissociation of silicon-containing gasses at the catalytic surface of a hot filament. Advantages of this technique

  7. Hot-compress: A new postdeposition treatment for ZnO-based flexible dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Haque Choudhury, Mohammad Shamimul, E-mail: shamimul129@gmail.com [Department of Frontier Material, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555 (Japan); Department of Electrical and Electronic Engineering, International Islamic University Chittagong, b154/a, College Road, Chittagong 4203 (Bangladesh); Kishi, Naoki; Soga, Tetsuo [Department of Frontier Material, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555 (Japan)

    2016-08-15

    Highlights: • A new postdeposition treatment named hot-compress is introduced. • Hot-compression gives homogeneous compact layer ZnO photoanode. • I-V and EIS analysis data confirms the efficacy of this method. • Charge transport resistance was reduced by the application of hot-compression. - Abstract: This article introduces a new postdeposition treatment named hot-compress for flexible zinc oxide–base dye-sensitized solar cells. This postdeposition treatment includes the application of compression pressure at an elevated temperature. The optimum compression pressure of 130 Ma at an optimum compression temperature of 70 °C heating gives better photovoltaic performance compared to the conventional cells. The aptness of this method was confirmed by investigating scanning electron microscopy image, X-ray diffraction, current-voltage and electrochemical impedance spectroscopy analysis of the prepared cells. Proper heating during compression lowers the charge transport resistance, longer the electron lifetime of the device. As a result, the overall power conversion efficiency of the device was improved about 45% compared to the conventional room temperature compressed cell.

  8. Modelling hot electron generation in short pulse target heating experiments

    Directory of Open Access Journals (Sweden)

    Sircombe N.J.

    2013-11-01

    Full Text Available Target heating experiments planned for the Orion laser facility, and electron beam driven fast ignition schemes, rely on the interaction of a short pulse high intensity laser with dense material to generate a flux of energetic electrons. It is essential that the characteristics of this electron source are well known in order to inform transport models in radiation hydrodynamics codes and allow effective evaluation of experimental results and forward modelling of future campaigns. We present results obtained with the particle in cell (PIC code EPOCH for realistic target and laser parameters, including first and second harmonic light. The hot electron distributions are characterised and their implications for onward transport and target heating are considered with the aid of the Monte-Carlo transport code THOR.

  9. Confinement of hot, hard x-ray producing electrons in solar flares

    International Nuclear Information System (INIS)

    Smith, D.F.; Lilliequist, C.G.

    1979-01-01

    Possible thermal models for solar, hard X-ray emission, consisting of small volumes in which the electrons are rapidly heated to 4 x 10 8 K, are examined to determine under what conditions such models can be more efficient than nonthermal models. The primary energy-loss mechanism in these models is source expansion due to heat conduction which deviates from its classical value by mechanisms which are reviewed and systematized. One such mechanism is saturation of the heat flux at its maximum possible value, corresponding to direct convection by electrons. Another mechanism is anomalous limitation of the heat flux due to instability of the return current which must compensate the electron current carrying the heat. A simple, one-dimensional model in which a section of the flux tube of constant density is heated to 4 x 10 8 K is analyzed. A conduction front, determined by the above collisionless process, moves along the flux tube at the head of the expanding source. A more realistic, one-dimensional, one-fluid, two-temperature model with a spatially and temporally varying energy source which delivers energy to the electrons at a finite rate is formulated and solved numerically. This results in some ion heating and mass motions which, by themselves, represent only a small energy loss. However, because of changes in the anomalous limitation of the heat flux with higher ion temperature, the expansion losses increase considerably

  10. Theoretical model of an evacuated tube heat pipe solar collector integrated with phase change material

    International Nuclear Information System (INIS)

    Naghavi, M.S.; Ong, K.S.; Badruddin, I.A.; Mehrali, M.; Silakhori, M.; Metselaar, H.S.C.

    2015-01-01

    The purpose of this paper is to model theoretically a solar hot water system consisting of an array of ETHPSC (evacuated tube heat pipe solar collectors) connected to a common manifold filled with phase change material and acting as a LHTES (latent heat thermal energy storage) tank. Solar energy incident on the ETHPSC is collected and stored in the LHTES tank. The stored heat is then transferred to the domestic hot water supply via a finned heat exchanger pipe placed inside the tank. A combination of mathematical algorithms is used to model a complete process of the heat absorption, storage and release modes of the proposed system. The results show that for a large range of flow rates, the thermal performance of the ETHPSC-LHTES system is higher than that of a similar system without latent heat storage. Furthermore, the analysis shows that the efficiency of the introduced system is less sensitive to the draw off water flowrate than a conventional system. Analysis indicates that this system could be applicable as a complementary part to conventional ETHPSC systems to be able to produce hot water at night time or at times with weak radiation. - Highlights: • The ETHPSC is integrated with PCM at manifold side for night hot water demands. • The thermal performance of the ETHPSC-PCM is often higher than the baseline model. • The efficiency of the proposed model is stable for different flow rates. • Using PCM as thermal storage increases reliability on the performance of the system.

  11. Modeling Heat Flow In a Calorimeter Equipped With a Textured Solar Collector

    Science.gov (United States)

    Jaworske, Donald A.; Allen, Bradley J.

    2001-01-01

    Heat engines are being considered for generating electric power for minisatellite applications, particularly for those missions in high radiation threat orbits. To achieve this objective, solar energy must be collected and transported to the hot side of the heat engine. A solar collector is needed having the combined properties of high solar absorptance, low infrared emittance, and high thermal conductivity. To test candidate solar collector concepts, a simple calorimeter was designed, manufactured, and installed in a bench top vacuum chamber to measure heat flow. In addition, a finite element analysis model of the collector/calorimeter combination was made to model this heat flow. The model was tuned based on observations from the as-manufactured collector/calorimeter combination. In addition, the model was exercised to examine other collector concepts, properties, and scale up issues.

  12. Material cycling solar system modeled ecosystem; Seitaikei wo model to shita busshitsu junkangata solar system

    Energy Technology Data Exchange (ETDEWEB)

    Sato, M [Hachinohe Institute of Technology, Aomori (Japan)

    1996-10-27

    It is proposed to establish an integrated system close to a natural ecosystem for an industrial complex, taking that in Hachinohe City, Aomori Pref. as the conceptual site. It is a system in which materials are recycled by solar energy and industrial waste heat for a complex food industry. The conceptual site, although blessed with various marine products, are sometimes attacked by cold weather. Waste heat from a 250,000kW power plant, if transported by EHD heat pipes to the site, could provide roughly 400 times the heat required for production of agricultural and marine products, such as cabbages and fish meat. The waste heat, coupled with solar energy, should solve the problems resulting from hot waste water, if they could be utilized for the industrial purposes. The food industrial site that produces agricultural and marine products is considered to be suited as the center of the solar industrial complex incorporating farms. 5 refs., 3 figs.

  13. Parameterization models for solar radiation and solar technology applications

    International Nuclear Information System (INIS)

    Khalil, Samy A.

    2008-01-01

    Solar radiation is very important for the evaluation and wide use of solar renewable energy systems. The development of calibration procedures for broadband solar radiation photometric instrumentation and the improvement of broadband solar radiation measurement accuracy have been done. An improved diffuse sky reference and photometric calibration and characterization software for outdoor pyranometer calibrations are outlined. Parameterizations for direct beam, total hemispherical and diffuse sky radiation and solar radiation technology are briefly reviewed. The uncertainties for various broadband solar radiations of solar energy and atmospheric effects are discussed. The varying responsivities of solar radiation with meteorological, statistical and climatological parameters and possibility atmospheric conditions was examined

  14. Parameterization models for solar radiation and solar technology applications

    Energy Technology Data Exchange (ETDEWEB)

    Khalil, Samy A. [National Research Institute of Astronomy and Geophysics, Solar and Space Department, Marsed Street, Helwan, 11421 Cairo (Egypt)

    2008-08-15

    Solar radiation is very important for the evaluation and wide use of solar renewable energy systems. The development of calibration procedures for broadband solar radiation photometric instrumentation and the improvement of broadband solar radiation measurement accuracy have been done. An improved diffuse sky reference and photometric calibration and characterization software for outdoor pyranometer calibrations are outlined. Parameterizations for direct beam, total hemispherical and diffuse sky radiation and solar radiation technology are briefly reviewed. The uncertainties for various broadband solar radiations of solar energy and atmospheric effects are discussed. The varying responsivities of solar radiation with meteorological, statistical and climatological parameters and possibility atmospheric conditions was examined. (author)

  15. Hybrid solar-PLG system for industrial scale steam and hot water generation; Sistema hibrido solar-GLP para geracao de vapor e agua quente em escala industrial

    Energy Technology Data Exchange (ETDEWEB)

    Saidel, Marco A.; Monteiro, Marcio D.; Gimenes, Andre L.V.; Fujii, Ricardo J. [Universidade de Sao Paulo (GEPEA/EPUSP), SP (Brazil). Dept. Engenharia Energia e Automacao Eletricas. Grupo de Energia], e-mail: saidel@pea.usp.br, e-mail: marcio.monteiro@poli.usp.br, e-mail: gimenes@gmail.com, e-mail: fujii@gmail.com

    2008-07-01

    This paper presents an initiative conceived for attending to objectives of the PUREFA (Program for Rational Use of Energy and Alternative Sources) of the Sao Paulo university, Brazil. The indicative consists of the implantation of a solar collector system for pre-heating of the water used in the production of the steam consumed at the university restaurant, with a production of 5800 meals per day. This system (auxiliary to the original steam boiler) pre-heats the water of the boiler minimizing the energy expenses for the production of steam and hot water.

  16. Test and evaluation of Fern Engineering Company, Incorporated, solar heating and hot water system. [structural design criteria and system effectiveness

    Science.gov (United States)

    1979-01-01

    Tests, test results, examination and evaluation by Underwriters Laboratory, Inc., of a single family solar heating and hot water system consisting of collector, storage, control, transport, and data acquisition are presented. The structural characteristics of the solar flat plate collectors were evaluated according to snow and wind loads indicated in various building codes to determine their suitability for use both Michigan and Pennsylvania where prototype systems were installed. The flame spread classification of the thermal insulation is discussed and the fire tests conducted on components are described. The operation and dielectrics withstand tests of the energy transport module indicate the module is capable of rated air delivery. Tests of the control panel indicate the relay coil temperatures exceed the temperature limits allowed for the insulating materials involved.

  17. Physicochemical model for reactive sputtering of hot target

    Energy Technology Data Exchange (ETDEWEB)

    Shapovalov, Viktor I., E-mail: vishapovalov@mail.ru; Karzin, Vitaliy V.; Bondarenko, Anastasia S.

    2017-02-05

    A physicochemical model for reactive magnetron sputtering of a metal target is described in this paper. The target temperature in the model is defined as a function of the ion current density. Synthesis of the coating occurs due to the surface chemical reaction. The law of mass action, the Langmuir isotherm and the Arrhenius equation for non-isothermal conditions were used for mathematical description of the reaction. The model takes into consideration thermal electron emission and evaporation of the target surface. The system of eight algebraic equations, describing the model, was solved for the tantalum target sputtered in the oxygen environment. It was established that the hysteresis effect disappears with the increase of the ion current density. - Highlights: • When model is applied for a cold target, hysteresis width is proportional to the ion current density. • Two types of processes of hot target sputtering are possible, depending on the current density: with and without the hysteresis. • Sputtering process is dominant at current densities less than 50 A/m{sup 2} and evaporation can be neglected. • For current densities over 50 A/m{sup 2} the hysteresis width reaches its maximum and the role of evaporation increases.

  18. Solar heating, cooling, and domestic hot water system installed at Kaw Valley State Bank and Trust Company, Topeka, Kansas. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-11-01

    The building has approximately 5600 square feet of conditioned space. Solar energy is used for space heating, space cooling, and preheating domestic hot water (DHW). The solar energy system has an array of evacuated tube-type collectors with an area of 1068 square feet. A 50/50 solution of ethylene glycol and water is the transfer medium that delivers solar energy to a tube-in-shell heat exchanger that in turn delivers solar-heated water to a 1100 gallon pressurized hot water storage tank. When solar energy is insufficient to satisfy the space heating and/or cooling demand, a natural gas-fired boiler provides auxiliary energy to the fan coil loops and/or the absorption chillers. Extracts from the site files, specification references, drawings, and installation, operation and maintenance instructions are included.

  19. Solar heat-pipe wick modeling

    Energy Technology Data Exchange (ETDEWEB)

    Andraka, C.E.

    1999-07-01

    Stirling-cycle engines have been identified as a promising technology for the conversion of concentrated solar energy into usable electrical power. In previous experimental work, the author has demonstrated that a heat pipe receiver can significantly improve system performance over a directly-illuminated heater head. The design and operating conditions of a heat pipe receiver differ significantly from typical laboratory heat pipes. New wick structures have been developed to exploit the characteristics of the solar generation system. Typically, these wick structures allow vapor generation within the wick. Conventional heat pipe models do not handle this enhancement, yet it can more than double the performance of the wick. In this study, the author developed a steady-state model of a boiling-enhanced wick for a solar heat pipe receiver. The model is used for design-point calculations and is written in FORTRAN90. Some limited comparisons have been made with actual test data.

  20. Collective plasma effects associated with the continuous injection model of solar flare particle streams

    International Nuclear Information System (INIS)

    Vlahos, L.; Paradopoulos, K.

    1979-01-01

    A modified continous injection model for impulsive solar flares that includes self-consistently plasma nonlinearities based on the concept of marginal stability is presented. A quasi-stationary state is established, composed of a hot truncated electron Maxwellian distribution confined by acoustic turbulence on the top of the loop and energetic electron beams precipitating in the chromosphere. It is shown that the radiation properties of the models are in accordance with observations

  1. Collective plasma effects associated with the continuous injection model of solar flare particle streams

    Science.gov (United States)

    Vlahos, L.; Papadopoulos, K.

    1979-01-01

    A modified continuous injection model for impulsive solar flares that includes self-consistent plasma nonlinearities based on the concept of marginal stability is presented. A quasi-stationary state is established, composed of a hot truncated electron Maxwellian distribution confined by acoustic turbulence on the top of the loop and energetic electron beams precipitating in the chromosphere. It is shown that the radiation properties of the model are in accordance with observations.

  2. Hot Deformation Behavior and a Two-Stage Constitutive Model of 20Mn5 Solid Steel Ingot during Hot Compression

    Directory of Open Access Journals (Sweden)

    Min Liu

    2018-03-01

    Full Text Available 20Mn5 steel is widely used in the manufacture of heavy hydro-generator shaft forging due to its strength, toughness, and wear resistance. However, the hot deformation and recrystallization behaviors of 20Mn5 steel compressed under a high temperature were not studied. For this article, hot compression experiments under temperatures of 850–1200 °C and strain rates of 0.01 s−1–1 s−1 were conducted using a Gleeble-1500D thermo-mechanical simulator. Flow stress-strain curves and microstructure after hot compression were obtained. Effects of temperature and strain rate on microstructure are analyzed. Based on the classical stress-dislocation relationship and the kinetics of dynamic recrystallization, a two-stage constitutive model is developed to predict the flow stress of 20Mn5 steel. Comparisons between experimental flow stress and predicted flow stress show that the predicted flow stress values are in good agreement with the experimental flow stress values, which indicates that the proposed constitutive model is reliable and can be used for numerical simulation of hot forging of 20Mn5 solid steel ingot.

  3. Modeling Hot-Spot Contributions in Shocked High Explosives at the Mesoscale

    Energy Technology Data Exchange (ETDEWEB)

    Harrier, Danielle [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-08-12

    When looking at performance of high explosives, the defects within the explosive become very important. Plastic bonded explosives, or PBXs, contain voids of air and bonder between the particles of explosive material that aid in the ignition of the explosive. These voids collapse in high pressure shock conditions, which leads to the formation of hot spots. Hot spots are localized high temperature and high pressure regions that cause significant changes in the way the explosive material detonates. Previously hot spots have been overlooked with modeling, but now scientists are realizing their importance and new modeling systems that can accurately model hot spots are underway.

  4. Testing of Solar Heated Domestic Hot Water System for Solahart Scandinavia ApS

    DEFF Research Database (Denmark)

    Andersen, Elsa

    1997-01-01

    The solar heating system marketed by Solahart Scandinavia ApS was tested in the Institutes test facility for SDHWsystems. The test results are described in the report.......The solar heating system marketed by Solahart Scandinavia ApS was tested in the Institutes test facility for SDHWsystems. The test results are described in the report....

  5. Hot-electron-based solar energy conversion with metal-semiconductor nanodiodes

    Science.gov (United States)

    Lee, Young Keun; Lee, Hyosun; Lee, Changhwan; Hwang, Euyheon; Park, Jeong Young

    2016-06-01

    Energy dissipation at metal surfaces or interfaces between a metal and a dielectric generally results from elementary excitations, including phonons and electronic excitation, once external energy is deposited to the surface/interface during exothermic chemical processes or an electromagnetic wave incident. In this paper, we outline recent research activities to develop energy conversion devices based on hot electrons. We found that photon energy can be directly converted to hot electrons and that hot electrons flow through the interface of metal-semiconductor nanodiodes where a Schottky barrier is formed and the energy barrier is much lower than the work function of the metal. The detection of hot electron flow can be successfully measured using the photocurrent; we measured the photoyield of photoemission with incident photons-to-current conversion efficiency (IPCE). We also show that surface plasmons (i.e. the collective oscillation of conduction band electrons induced by interaction with an electromagnetic field) are excited on a rough metal surface and subsequently decay into secondary electrons, which gives rise to enhancement of the IPCE. Furthermore, the unique optical behavior of surface plasmons can be coupled with dye molecules, suggesting the possibility for producing additional channels for hot electron generation.

  6. Equivalent circuit-level model of quantum cascade lasers with integrated hot-electron and hot-phonon effects

    Science.gov (United States)

    Yousefvand, H. R.

    2017-12-01

    We report a study of the effects of hot-electron and hot-phonon dynamics on the output characteristics of quantum cascade lasers (QCLs) using an equivalent circuit-level model. The model is developed from the energy balance equation to adopt the electron temperature in the active region levels, the heat transfer equation to include the lattice temperature, the nonequilibrium phonon rate to account for the hot phonon dynamics and simplified two-level rate equations to incorporate the carrier and photon dynamics in the active region. This technique simplifies the description of the electron-phonon interaction in QCLs far from the equilibrium condition. Using the presented model, the steady and transient responses of the QCLs for a wide range of sink temperatures (80 to 320 K) are investigated and analysed. The model enables us to explain the operating characteristics found in QCLs. This predictive model is expected to be applicable to all QCL material systems operating in pulsed and cw regimes.

  7. Electric solar wind sail mass budget model

    Directory of Open Access Journals (Sweden)

    P. Janhunen

    2013-02-01

    Full Text Available The electric solar wind sail (E-sail is a new type of propellantless propulsion system for Solar System transportation, which uses the natural solar wind to produce spacecraft propulsion. The E-sail consists of thin centrifugally stretched tethers that are kept charged by an onboard electron gun and, as such, experience Coulomb drag through the high-speed solar wind plasma stream. This paper discusses a mass breakdown and a performance model for an E-sail spacecraft that hosts a mission-specific payload of prescribed mass. In particular, the model is able to estimate the total spacecraft mass and its propulsive acceleration as a function of various design parameters such as the number of tethers and their length. A number of subsystem masses are calculated assuming existing or near-term E-sail technology. In light of the obtained performance estimates, an E-sail represents a promising propulsion system for a variety of transportation needs in the Solar System.

  8. Dynamic fracture and hot-spot modeling in energetic composites

    Science.gov (United States)

    Grilli, Nicolò; Duarte, Camilo A.; Koslowski, Marisol

    2018-02-01

    Defects such as cracks, pores, and particle-matrix interface debonding affect the sensitivity of energetic materials by reducing the time-to-ignition and the threshold pressure to initiate an explosion. Frictional sliding of preexisting cracks is considered to be one of the most important causes of localized heating. Therefore, understanding the dynamic fracture of crystalline energetic materials is of extreme importance to assess the reliability and safety of polymer-bonded explosives. Phase field damage model simulations, based on the regularization of the crack surface as a diffuse delta function, are used to describe crack propagation in cyclotetramethylene-tetranitramine crystals embedded in a Sylgard matrix. A thermal transport model that includes heat generation by friction at crack interfaces is coupled to the solution of crack propagation. 2D and 3D dynamic compression simulations are performed with different boundary velocities and initial distributions of cracks and interface defects to understand their effect on crack propagation and heat generation. It is found that, at an impact velocity of 400 m/s, localized damage at the particle-binder interface is of key importance and that the sample reaches temperatures high enough to create a hot-spot that will lead to ignition. At an impact velocity of 10 m/s, preexisting cracks advanced inside the particle, but the increase of temperature will not cause ignition.

  9. THE ATMOSPHERIC CIRCULATION OF THE HOT JUPITER WASP-43b: COMPARING THREE-DIMENSIONAL MODELS TO SPECTROPHOTOMETRIC DATA

    Energy Technology Data Exchange (ETDEWEB)

    Kataria, Tiffany; Showman, Adam P. [Department of Planetary Sciences and Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ 85721 (United States); Fortney, Jonathan J.; Line, Michael R. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Stevenson, Kevin B.; Kreidberg, Laura; Bean, Jacob L. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Désert, Jean-Michel, E-mail: tkataria@astro.ex.ac.uk [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States)

    2015-03-10

    The hot Jupiter WASP-43b (2 M{sub J}, 1 R{sub J}, T {sub orb} = 19.5 hr) has now joined the ranks of transiting hot Jupiters HD 189733b and HD 209458b as an exoplanet with a large array of observational constraints. Because WASP-43b receives a similar stellar flux as HD 209458b but has a rotation rate four times faster and a higher gravity, studying WASP-43b probes the effect of rotation rate and gravity on the circulation when stellar irradiation is held approximately constant. Here we present three-dimensional (3D) atmospheric circulation models of WASP-43b, exploring the effects of composition, metallicity, and frictional drag. We find that the circulation regime of WASP-43b is not unlike other hot Jupiters, with equatorial superrotation that yields an eastward-shifted hotspot and large day-night temperature variations (∼600 K at photospheric pressures). We then compare our model results to Hubble Space Telescope (HST)/WFC3 spectrophotometric phase curve measurements of WASP-43b from 1.12 to 1.65 μm. Our results show the 5× solar model light curve provides a good match to the data, with a peak flux phase offset and planet/star flux ratio that is similar to observations; however, the model nightside appears to be brighter. Nevertheless, our 5× solar model provides an excellent match to the WFC3 dayside emission spectrum. This is a major success, as the result is a natural outcome of the 3D dynamics with no model tuning. These results demonstrate that 3D circulation models can help interpret exoplanet atmospheric observations, even at high resolution, and highlight the potential for future observations with HST, James Webb Space Telescope, and other next-generation telescopes.

  10. Cost-effectiveness optimization of a solar hot water heater with integrated storage system

    International Nuclear Information System (INIS)

    Kamaruzzaman Sopian; Syahri, M.; Shahrir, A.; Mohd Yusof Othman; Baharuddin Yatim

    2006-01-01

    Solar processes are generally characterized by high first cost and low operating costs. Therefore, the basic economic problem is one of comparing an initial known investment with estimated future operating cost. This paper present the cost-benefit ratio of solar collector with integrated storage system. Evaluation of the annual cost (AC) and the annual energy gain (AEG) of the collector are performed and the ratio of AC/AEG or the cost benefit ratio is presented for difference combination of mass flow rate, solar collector length and channel depth. Using these cost-effectiveness curves, the user can select optimum design features, which correspond to minimum AC/AEG

  11. Investigating the impact of different thermal comfort models for zero energy buildings in hot climates

    NARCIS (Netherlands)

    Attia, S.G.; Hensen, J.L.M.

    2014-01-01

    The selection of a thermal comfort model has a major impact on energy consumption of Net Zero Energy Buildings (NZEBs) in hot climates. The objective of this paper is to compare the influence of using different comfort models for zero energy buildings in hot climates. The paper compares the impact

  12. Modeling 3-D solar wind structure

    Czech Academy of Sciences Publication Activity Database

    Odstrčil, Dušan

    2003-01-01

    Roč. 32, č. 4 (2003), s. 497-506 ISSN 0273-1177 R&D Projects: GA AV ČR IAA3003003; GA AV ČR IBS1003006 Institutional research plan: CEZ:AV0Z1003909 Keywords : solar wind * modeling Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.483, year: 2003

  13. TRANSMISSION SPECTRA OF THREE-DIMENSIONAL HOT JUPITER MODEL ATMOSPHERES

    International Nuclear Information System (INIS)

    Fortney, J. J.; Shabram, M.; Showman, A. P.; Lian, Y.; Lewis, N. K.; Freedman, R. S.; Marley, M. S.

    2010-01-01

    We compute models of the transmission spectra of planets HD 209458b, HD 189733b, and generic hot Jupiters. We examine the effects of temperature, surface gravity, and metallicity for the generic planets as a guide to understanding transmission spectra in general. We find that carbon dioxide absorption at 4.4 and 15 μm is prominent at high metallicity, and is a clear metallicity indicator. For HD 209458b and HD 189733b, we compute spectra for both one-dimensional and three-dimensional model atmospheres and examine the differences between them. The differences are usually small, but can be large if atmospheric temperatures are near important chemical abundance boundaries. The calculations for the three-dimensional atmospheres, and their comparison with data, serve as constraints on these dynamical models that complement the secondary eclipse and light curve data sets. For HD 209458b, even if TiO and VO gases are abundant on the dayside, their abundances can be considerably reduced on the cooler planetary limb. However, given the predicted limb temperatures and TiO abundances, the model's optical opacity is too high. For HD 189733b we find a good match with some infrared data sets and constrain the altitude of a postulated haze layer. For this planet, substantial differences can exist between the transmission spectra of the leading and trailing hemispheres, which are an excellent probe of carbon chemistry. In thermochemical equilibrium, the cooler leading hemisphere is methane-dominated, and the hotter trailing hemisphere is CO-dominated, but these differences may be eliminated by non-equilibrium chemistry due to vertical mixing. It may be possible to constrain the carbon chemistry of this planet, and its spatial variation, with James Webb Space Telescope.

  14. Solar heating, cooling, and hot water systems installed at Richland, Washington

    Science.gov (United States)

    1979-01-01

    The project described is part of the U. S. Department of Energy's solar demonstration program, and became operational in April 1978. The solar system uses 6,000 square feet of flat-plate liquid collectors in a closed loop to deliver solar energy through a liquid-liquid heat exchanger to the building heat-pump duct work or 9,000-gallon thermal energy storage tank. A 25-ton Arkla solar-driven absorption chiller provides the cooling, in conjunction with a 2,000 gallon chilled water storage tank and reflective ponds on three sides of the building surplus heat. A near-by building is essentially identical except for having conventional heat-pump heating and cooling, and can serve as an experimental control. An on-going public relations program was provided from the beginning of the program, and resulted in numerous visitors and tour groups.

  15. Solar heating and hot water system installed at the Senior Citizen Center, Huntsville, Alabama

    Science.gov (United States)

    1980-01-01

    The solar energy system installed at the Huntsville Senior Citizen Center is described. Detailed drawings of the complete system and discussions of the planning, the hardware, recommendations, and other pertinent information are presented.

  16. Solar Cogeneration of Electricity and Hot Water at DoD Installations

    Science.gov (United States)

    2014-05-01

    the cogeneration system displaces more energy (the impact is not 4-5X because the GHG intensity factors for offsetting electricity generation and...visibility to Army energy managers. Additional benefits of Cogenra’s solar cogeneration system are the engineering and design jobs at Cogenra’s...certification. Solar cogeneration can help earn LEED points in three areas: Optimizing Energy Efficiency Performance, On-Site Renewable Energy , and

  17. System design package for SIMS prototype system 4, solar heating and domestic hot water

    Science.gov (United States)

    1978-01-01

    The system consisted of a modular designed prepackaged solar unit, containing solar collectors, a rock storage container, blowers, dampers, ducting, air-to-water heat exchanger, DHW preheat tank, piping, and system controls. The system was designed to be installed adjacent to a small single family dwelling. The description, performance specification, subsystem drawings, verification plan/procedure, and hazard analysis of the system were packaged for evaluation.

  18. Solar hot water for household and institutional use in Bujumbura, Burundi

    International Nuclear Information System (INIS)

    Katihabwa, J.

    1990-01-01

    This paper reports on solar energy which is clean and renewable. It is the primary source for a wide range of energy resources such as biomass, hydraulics, coal, peat and petroleum. Until recently, the sun was the major source of energy used by man to satisfy his needs. The extraction and use of fossil fuels became important with the technological and industrial development that took place in the nineteenth century. For countries without fossil fuels (such as petroleum and coal), solar energy is an important asset. The oil crisis of 1973 clearly showed the limits of fossil fuel consumption. The crisis slowed down and, in some cases, severely hampered economic growth in many developing countries. To this day, fossil fuels remain expensive for many developing countries which have to part with a significant share of their meagre convertible currency resources to import fossil fuels. It is thus imperative that developing countries should investigate the possibility of developing solar energy systems that can reduce their dependence on fossil fuels. In the short term, high investment costs and shortage of qualified manpower are major constraints on the development of solar energy systems. In the long run, however, the benefits of solar energy systems are expected to overcome these constraints. The benefits include low operation costs and non-generation of pollutants. The decentralized nature of solar energy is an asset in the isolated rural areas of Africa. It is possible to build small solar units and this provide energy security and autonomy at the level of a community and even at the level of an individual. Solar energy has, however, one major disadvantage - its energy density is low (1.0 kw per square metre on the earth surface, after taking absorption losses into account)

  19. Solar heating and hot water system installed at Charlotte Memorial Hospital, Charlotte, North Carolina

    Science.gov (United States)

    1981-01-01

    Detailed information regarding the design and installation of a heating and hot water system in a commercial application is given. This information includes descriptions of system and building, design philosophy, control logic operation modes, design and installation drawing and a brief description of problems encountered and their solutions.

  20. Transportation conformity particulate matter hot-spot air quality modeling.

    Science.gov (United States)

    2013-07-01

    In light of the new development in particulate matter (PM) hot-spot regulations and Illinois Department : of Transportation (IDOT)s National Environmental Policy Act (NEPA) documentation requirements, : this project is intended to (1) perform and ...

  1. Models for prediction of global solar radiation on horizontal surface ...

    African Journals Online (AJOL)

    The estimation of global solar radiation continues to play a fundamental role in solar engineering systems and applications. This paper compares various models for estimating the average monthly global solar radiation on horizontal surface for Akure, Nigeria, using solar radiation and sunshine duration data covering years ...

  2. Densification of sintered molybdenum during hot upsetting: experiments and modelling

    International Nuclear Information System (INIS)

    Parteder, E.; Kopp, R.

    1999-01-01

    The densification behaviour of sintered molybdenum is investigated experimentally and by modelling using a pressure dependent plasticity model. Therefore the yield condition of Gurson, extended by Tvergaard is used. The uniaxial compression test is applied to determine the evolution of the density as well as the stress-strain curves for the porous metal. Powder metallurgical molybdenum exhibits closed porosity after consolidation due to sintering with nearly spherical shaped pores. The experimental results show that the densification, especially during the first stage of deformation, is different from that of powder compacts or partially consolidated powder materials with open porosity. During hot upsetting, the pores change their size and shape. This behaviour strongly affects the densification rate. For an accurate prediction of the evolution of the density using Gurson's model, the parameters q 1 and q 2 introduced by Tvergaard, will be defined as internal variables. The use of internal variables is justified by the fact that the pores change their shape during deformation, although the link between the internal variables and the pore shape is not explicitly established in this paper. If the loading is proportional (which means that the ratio of the stress-components does not change with plastic strain), the pore shape can be associated with the applied plastic strain. With this association the parameters q i can be defined as a function from the invariant quantity equivalent plastic strain, which can be used as the internal variable in the finite element simulation. The influence of the porosity on the flow stress at different levels of plastic strain will also be investigated and is used as a second information to fit both parameters q 1 and q 2 . (orig.)

  3. Development of the RETRAN hot spot model for KSNP

    International Nuclear Information System (INIS)

    Kim, Yo Han; Kim, Yong Deog; Lee, Chang Sup

    2004-01-01

    Under the funding of Ministry of Commerce, Industry and Energy, Korea Electric Power Research Institute (KEPRI), the research center of Korea Electric Power Corporation (KEPCO), has been developed the in-house non-loss-of-coolant accident (non-LOCA) analysis methodology for Korea Standard Nuclear Power Plants (KSNP). To develop the methodology, the related documents of EPRI and vendors were examined and the methodologies of some foreign utilities were reviewed also to compensate for lack of capabilities. In fact, one of the major goals of the project is to build the code and methodology systems to replace the restricted codes by U. S. Government mentioned in the Technical Transfer Agreement between KEPCO and ABB-CE. To achieve the goal, KEPRI has developed the methodology based on general-purpose system codes, such as RETRAN, RELAP and MASTER. Despite the efforts, some functional weaks were raised from the users. So, KEPRI has developed the RETRAN hot spot model (HSM) to compensate some functions used for the estimation of the fuel temperature and enthalpy, cladding surface temperature, etc. In current methodology for KSNP, the parameters are calculated with STRIKIN-II code, which is one of the restricted codes. In this paper the development of HSM is described. And to estimate the feasibility of the model, the rod ejection accident (REA) was analyzed and the results were compared with those calculated by STRIKIN-II code. Through the feasibility study, it was concluded that the developed model showed the acceptable results and could be used further works

  4. Review of solar nebula models

    International Nuclear Information System (INIS)

    Wood, J.A.; Morfill, G.E.

    1988-01-01

    The major changes that have occurred in thinking about protosolar nebula models are discussed. The concept favored by astrophysicists for the last decade, that of a viscous accretion-disk nebula, is examined. The properties of recent accretion-disk models that are most relevant to chondrite-forming processes are noted. 27 references

  5. Solar Advisor Model User Guide for Version 2.0

    Energy Technology Data Exchange (ETDEWEB)

    Gilman, P.; Blair, N.; Mehos, M.; Christensen, C.; Janzou, S.; Cameron, C.

    2008-08-01

    The Solar Advisor Model (SAM) provides a consistent framework for analyzing and comparing power system costs and performance across the range of solar technologies and markets, from photovoltaic systems for residential and commercial markets to concentrating solar power and large photovoltaic systems for utility markets. This manual describes Version 2.0 of the software, which can model photovoltaic and concentrating solar power technologies for electric applications for several markets. The current version of the Solar Advisor Model does not model solar heating and lighting technologies.

  6. Solar energy market penetration models - Science or number mysticism

    Science.gov (United States)

    Warren, E. H., Jr.

    1980-01-01

    The forecast market potential of a solar technology is an important factor determining its R&D funding. Since solar energy market penetration models are the method used to forecast market potential, they have a pivotal role in a solar technology's development. This paper critiques the applicability of the most common solar energy market penetration models. It is argued that the assumptions underlying the foundations of rigorously developed models, or the absence of a reasonable foundation for the remaining models, restrict their applicability.

  7. Non-LTE line-blanketed model atmospheres of hot stars. 2: Hot, metal-rich white dwarfs

    Science.gov (United States)

    Lanz, T.; Hubeny, I.

    1995-01-01

    We present several model atmospheres for a typical hot metal-rich DA white dwarf, T(sub eff) = 60,000 K, log g = 7.5. We consider pure hydrogen models, as well as models with various abundances of two typical 'trace' elements-carbon and iron. We calculte a number of Local Thermodynamic Equilibrium (LTE) and non-LTE models, taking into account the effect of numerous lines of these elements on the atmospheric structure. We demostrate that while the non-LTE effects are notvery significant for pure hydrogen models, except for describing correctly the central emission in H-alpha they are essential for predicting correctly the ionization balance of metals, such as carbon and iron. Previously reported discrepancies in LTE abundances determinations using C III and C IV lines are easily explained by non-LTE effects. We show that if the iron abundance is larger than 10(exp -5), the iron line opacity has to be considered not only for the spectrum synthesis, but also in the model construction itself. For such metal abundances, non-LTE metal line-blanketed models are needed for detailed abundance studies of hot, metal-rich white dwarfs. We also discuss the predicted Extreme Ultraviolet (EUV) spectrum and show that it is very sensitive to metal abundances, as well as to non-LTE effects.

  8. Plasma properties of hot coronal loops utilizing coordinated SMM and solar research rocket observations

    Science.gov (United States)

    Moses, J. Daniel

    1989-01-01

    Three improvements in photographic x-ray imaging techniques for solar astronomy are presented. The testing and calibration of a new film processor was conducted; the resulting product will allow photometric development of sounding rocket flight film immediately upon recovery at the missile range. Two fine grained photographic films were calibrated and flight tested to provide alternative detector choices when the need for high resolution is greater than the need for high sensitivity. An analysis technique used to obtain the characteristic curve directly from photographs of UV solar spectra were applied to the analysis of soft x-ray photographic images. The resulting procedure provides a more complete and straightforward determination of the parameters describing the x-ray characteristic curve than previous techniques. These improvements fall into the category of refinements instead of revolutions, indicating the fundamental suitability of the photographic process for x-ray imaging in solar astronomy.

  9. A hot Jupiter orbiting a 2-million-year-old solar-mass T Tauri star.

    Science.gov (United States)

    Donati, J F; Moutou, C; Malo, L; Baruteau, C; Yu, L; Hébrard, E; Hussain, G; Alencar, S; Ménard, F; Bouvier, J; Petit, P; Takami, M; Doyon, R; Collier Cameron, A

    2016-06-30

    Hot Jupiters are giant Jupiter-like exoplanets that orbit their host stars 100 times more closely than Jupiter orbits the Sun. These planets presumably form in the outer part of the primordial disk from which both the central star and surrounding planets are born, then migrate inwards and yet avoid falling into their host star. It is, however, unclear whether this occurs early in the lives of hot Jupiters, when they are still embedded within protoplanetary disks, or later, once multiple planets are formed and interact. Although numerous hot Jupiters have been detected around mature Sun-like stars, their existence has not yet been firmly demonstrated for young stars, whose magnetic activity is so intense that it overshadows the radial velocity signal that close-in giant planets can induce. Here we report that the radial velocities of the young star V830 Tau exhibit a sine wave of period 4.93 days and semi-amplitude 75 metres per second, detected with a false-alarm probability of less than 0.03 per cent, after filtering out the magnetic activity plaguing the spectra. We find that this signal is unrelated to the 2.741-day rotation period of V830 Tau and we attribute it to the presence of a planet of mass 0.77 times that of Jupiter, orbiting at a distance of 0.057 astronomical units from the host star. Our result demonstrates that hot Jupiters can migrate inwards in less than two million years, probably as a result of planet–disk interactions.

  10. An economic and performance design study of solar preheaters for domestic hot water heaters in North Carolina

    Science.gov (United States)

    Jones, C. B.; Smetana, F. O.

    1977-01-01

    The performance and estimated material costs for several solar preheaters for domestic hot water heaters using isolation levels present in North Carolina are presented. The effects of monthly variations in isolation and the direction of incident radiation are included. Demand is assumed at 13 gallons (49.2 liters) per day per person. The study shows that a closed circulation system with 82 gallons (310 liters) of preheated storage and 53.4 cu ft (4.94 cu m) of collector surface with single cover can be expected to cost about $800 and to repay it capital cost and interest (at 8%) in 5.2 years, assuming present electric rates increase at 5% per year.

  11. Hot Temperatures, Hostile Affect, Hostile Cognition, and Arousal: Tests of a General Model of Affective Aggression.

    Science.gov (United States)

    Anderson, Craig A.; And Others

    1995-01-01

    Used a general model of affective aggression to generate predictions concerning hot temperatures. Results indicated that hot temperatures produced increases in hostile affect, hostile cognition, and physiological arousal. Concluded that hostile affect, hostile cognitions, and excitation transfer processes may all increase the likelihood of biased…

  12. Technology Learning Activities. Design Brief--Measuring Inaccessible Distances. Alternative Energy Sources: Designing a Wind Powered Generator. Alternative Energy Sources: Designing a Hot Dog Heater Using Solar Energy.

    Science.gov (United States)

    Technology Teacher, 1991

    1991-01-01

    These three learning activities are on measuring accessible distances, designing a wind powered generator, and designing a hot dog heater using solar energy. Each activity includes description of context, objectives, list of materials and equipment, challenge to students, and evaluation questions. (SK)

  13. Investigation and optimisation of heat storage tanks for low-flow SDHW systems[Solar Domestic Hot Water

    Energy Technology Data Exchange (ETDEWEB)

    Knudsen, Soeren

    2004-07-01

    This thesis, 'Investigation and optimisation of heat storage tanks for low-flow SDHW systems', describes a study of the heat transfer and flow structure in vertical mantle heat exchangers for low-flow Solar Domestic Hot Water (SDHW) systems. The heat storage is a key component in SDHW systems and the vertical mantle heat exchanger is one of the most promising heat storage designs for low-flow SDHW systems. The study was carried out using a combination of experimental and numerical methods. Thermal experiments of mantle heat exchangers with different mantle inlet designs showed that the mantle inlet port with advantage can be located a distance from the top of the mantle. Consequently, the mantle heat exchangers marketed today can be improved by changing the mantle inlet position. The heat transfer and flow structure in mantle heat exchangers are rather complex and the thermal experiments were followed by investigations by means of advanced experimental and numerical techniques such as Particle Image Velocimetry (PIV) and Computational Fluid Dynamics (CFD). Using a transparent glass mantle tank, experimental flow visualisation was carried out with a PIV system. The flow structures inside the mantle and inside the tank were visualised and then compared with the flow structures predicted by CFD-models. The investigations showed that the CFD-models were able to model the flow in the mantle and in the tank correctly. The CFD-models were also validated by means of thermal experiments with a steel mantle tank. With the verified CFD-models, a parameter analysis was carried out for differently designed mantle heat exchangers for different typical conditions to reveal how the mantle tank parameters influence the flow structure and heat transfer in mantle heat exchangers. The heat transfer in the mantle near the mantle inlet port showed to be in the mixed convection regime, and as the distance from the inlet increased, natural convection started to dominate. The

  14. Evaluation of global solar radiation models for Shanghai, China

    International Nuclear Information System (INIS)

    Yao, Wanxiang; Li, Zhengrong; Wang, Yuyan; Jiang, Fujian; Hu, Lingzhou

    2014-01-01

    Highlights: • 108 existing models are compared and analyzed by 42 years meteorological data. • Fitting models based on measured data are established according to 42 years data. • All models are compared by recently 10 years meteorological data. • The results show that polynomial models are the most accurate models. - Abstract: In this paper, 89 existing monthly average daily global solar radiation models and 19 existing daily global solar radiation models are compared and analyzed by 42 years meteorological data. The results show that for existing monthly average daily global solar radiation models, linear models and polynomial models have been able to estimate global solar radiation accurately, and complex equation types cannot obviously improve the precision. Considering direct parameters such as latitude, altitude, solar altitude and sunshine duration can help improve the accuracy of the models, but indirect parameters cannot. For existing daily global solar radiation models, multi-parameter models are more accurate than single-parameter models, polynomial models are more accurate than linear models. Then measured data fitting monthly average daily global solar radiation models (MADGSR models) and daily global solar radiation models (DGSR models) are established according to 42 years meteorological data. Finally, existing models and fitting models based on measured data are comparative analysis by recent 10 years meteorological data, and the results show that polynomial models (MADGSR model 2, DGSR model 2 and Maduekwe model 2) are the most accurate models

  15. A feature-based approach to modeling protein-protein interaction hot spots.

    Science.gov (United States)

    Cho, Kyu-il; Kim, Dongsup; Lee, Doheon

    2009-05-01

    Identifying features that effectively represent the energetic contribution of an individual interface residue to the interactions between proteins remains problematic. Here, we present several new features and show that they are more effective than conventional features. By combining the proposed features with conventional features, we develop a predictive model for interaction hot spots. Initially, 54 multifaceted features, composed of different levels of information including structure, sequence and molecular interaction information, are quantified. Then, to identify the best subset of features for predicting hot spots, feature selection is performed using a decision tree. Based on the selected features, a predictive model for hot spots is created using support vector machine (SVM) and tested on an independent test set. Our model shows better overall predictive accuracy than previous methods such as the alanine scanning methods Robetta and FOLDEF, and the knowledge-based method KFC. Subsequent analysis yields several findings about hot spots. As expected, hot spots have a larger relative surface area burial and are more hydrophobic than other residues. Unexpectedly, however, residue conservation displays a rather complicated tendency depending on the types of protein complexes, indicating that this feature is not good for identifying hot spots. Of the selected features, the weighted atomic packing density, relative surface area burial and weighted hydrophobicity are the top 3, with the weighted atomic packing density proving to be the most effective feature for predicting hot spots. Notably, we find that hot spots are closely related to pi-related interactions, especially pi . . . pi interactions.

  16. Mathematical models for photovoltaic solar panel simulation

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Jose Airton A. dos; Gnoatto, Estor; Fischborn, Marcos; Kavanagh, Edward [Universidade Tecnologica Federal do Parana (UTFPR), Medianeira, PR (Brazil)], Emails: airton@utfpr.edu.br, gnoatto@utfpr.edu.br, fisch@utfpr.edu.br, kavanagh@utfpr.edu.br

    2008-07-01

    A photovoltaic generator is subject to several variations of solar intensity, ambient temperature or load, that change your point of operation. This way, your behavior should be analyzed by such alterations, to optimize your operation. The present work sought to simulate a photovoltaic generator, of polycrystalline silicon, by characteristics supplied by the manufacturer, and to compare the results of two mathematical models with obtained values of field, in the city of Cascavel, for a period of one year. (author)

  17. Development of a Greek solar map based on solar model estimations

    Science.gov (United States)

    Kambezidis, H. D.; Psiloglou, B. E.; Kavadias, K. A.; Paliatsos, A. G.; Bartzokas, A.

    2016-05-01

    The realization of Renewable Energy Sources (RES) for power generation as the only environmentally friendly solution, moved solar systems to the forefront of the energy market in the last decade. The capacity of the solar power doubles almost every two years in many European countries, including Greece. This rise has brought the need for reliable predictions of meteorological data that can easily be utilized for proper RES-site allocation. The absence of solar measurements has, therefore, raised the demand for deploying a suitable model in order to create a solar map. The generation of a solar map for Greece, could provide solid foundations on the prediction of the energy production of a solar power plant that is installed in the area, by providing an estimation of the solar energy acquired at each longitude and latitude of the map. In the present work, the well-known Meteorological Radiation Model (MRM), a broadband solar radiation model, is engaged. This model utilizes common meteorological data, such as air temperature, relative humidity, barometric pressure and sunshine duration, in order to calculate solar radiation through MRM for areas where such data are not available. Hourly values of the above meteorological parameters are acquired from 39 meteorological stations, evenly dispersed around Greece; hourly values of solar radiation are calculated from MRM. Then, by using an integrated spatial interpolation method, a Greek solar energy map is generated, providing annual solar energy values all over Greece.

  18. Probabilistic Models for Solar Particle Events

    Science.gov (United States)

    Adams, James H., Jr.; Dietrich, W. F.; Xapsos, M. A.; Welton, A. M.

    2009-01-01

    Probabilistic Models of Solar Particle Events (SPEs) are used in space mission design studies to provide a description of the worst-case radiation environment that the mission must be designed to tolerate.The models determine the worst-case environment using a description of the mission and a user-specified confidence level that the provided environment will not be exceeded. This poster will focus on completing the existing suite of models by developing models for peak flux and event-integrated fluence elemental spectra for the Z>2 elements. It will also discuss methods to take into account uncertainties in the data base and the uncertainties resulting from the limited number of solar particle events in the database. These new probabilistic models are based on an extensive survey of SPE measurements of peak and event-integrated elemental differential energy spectra. Attempts are made to fit the measured spectra with eight different published models. The model giving the best fit to each spectrum is chosen and used to represent that spectrum for any energy in the energy range covered by the measurements. The set of all such spectral representations for each element is then used to determine the worst case spectrum as a function of confidence level. The spectral representation that best fits these worst case spectra is found and its dependence on confidence level is parameterized. This procedure creates probabilistic models for the peak and event-integrated spectra.

  19. High-Fidelity Solar Power Income Modeling for Solar-Electric UAVs: Development and Flight Test Based Verification

    OpenAIRE

    Oettershagen, Philipp

    2017-01-01

    Solar power models are a crucial element of solar-powered UAV design and performance analysis. During the conceptual design phase, their accuracy directly relates to the accuracy of the predicted performance metrics and thus the final design characteristics of the solar-powered UAV. Likewise, during the operations phase of a solar-powered UAV accurate solar power income models are required to predict and assess the solar power system performance. However, the existing literature on solar-powe...

  20. Students To Compete in Model Solar Car Race

    Science.gov (United States)

    cars in the 1998 Junior Solar Sprint. The race will be held at the U.S. Department of Energy's (DOE Compete in Model Solar Car Race For more information contact: e:mail: Public Affairs Golden, Colo ., May 8, 1998 — Middle school students from across Colorado will design, build and race model solar

  1. Quantitative analysis of prediction models for hot cracking in ...

    Indian Academy of Sciences (India)

    A RodrМguez-Prieto

    2017-11-16

    Nov 16, 2017 ... In this paper, a systematic analysis of different methods of d-ferrite estimation is carried out based ... Keywords. d-Ferrite; hot cracking; prediction methods; stringency levels; decision tool. 1. .... prediction of d-ferrite content using a system of multi- ..... support the selection of some materials according to their.

  2. Validation of a Hot Water Distribution Model Using Laboratory and Field Data

    Energy Technology Data Exchange (ETDEWEB)

    Backman, C.; Hoeschele, M.

    2013-07-01

    Characterizing the performance of hot water distribution systems is a critical step in developing best practice guidelines for the design and installation of high performance hot water systems. Developing and validating simulation models is critical to this effort, as well as collecting accurate input data to drive the models. In this project, the ARBI team validated the newly developed TRNSYS Type 604 pipe model against both detailed laboratory and field distribution system performance data. Validation efforts indicate that the model performs very well in handling different pipe materials, insulation cases, and varying hot water load conditions. Limitations of the model include the complexity of setting up the input file and long simulation run times. In addition to completing validation activities, this project looked at recent field hot water studies to better understand use patterns and potential behavioral changes as homeowners convert from conventional storage water heaters to gas tankless units. Based on these datasets, we conclude that the current Energy Factor test procedure overestimates typical use and underestimates the number of hot water draws. This has implications for both equipment and distribution system performance. Gas tankless water heaters were found to impact how people use hot water, but the data does not necessarily suggest an increase in usage. Further study in hot water usage and patterns is needed to better define these characteristics in different climates and home vintages.

  3. Validation of a Hot Water Distribution Model Using Laboratory and Field Data

    Energy Technology Data Exchange (ETDEWEB)

    Backman, C. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States); Hoeschele, M. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States)

    2013-07-01

    Characterizing the performance of hot water distribution systems is a critical step in developing best practice guidelines for the design and installation of high performance hot water systems. Developing and validating simulation models is critical to this effort, as well as collecting accurate input data to drive the models. In this project, the Building America research team ARBI validated the newly developed TRNSYS Type 604 pipe model against both detailed laboratory and field distribution system performance data. Validation efforts indicate that the model performs very well in handling different pipe materials, insulation cases, and varying hot water load conditions. Limitations of the model include the complexity of setting up the input file and long simulation run times. This project also looked at recent field hot water studies to better understand use patterns and potential behavioral changes as homeowners convert from conventional storage water heaters to gas tankless units. The team concluded that the current Energy Factor test procedure overestimates typical use and underestimates the number of hot water draws, which has implications for both equipment and distribution system performance. Gas tankless water heaters were found to impact how people use hot water, but the data does not necessarily suggest an increase in usage. Further study in hot water usage and patterns is needed to better define these characteristics in different climates and home vintages.

  4. Modeling and simulation of photovoltaic solar panel

    International Nuclear Information System (INIS)

    Belarbi, M.; Haddouche, K.; Midoun, A.

    2006-01-01

    In this article, we present a new approach for estimating the model parameters of a photovoltaic solar panel according to the irradiance and temperature. The parameters of the one diode model are given from the knowledge of three operating points: short-circuit, open circuit, and maximum power. In the first step, the adopted approach concerns the resolution of the system of equations constituting the three operating points to write all the model parameters according to series resistance. Secondly, we make an iterative resolution at the optimal operating point by using the Newton-Raphson method to calculate the series resistance value as well as the model parameters. Once the panel model is identified, we consider other equations for taking into account the irradiance and temperature effect. The simulation results show the convergence speed of the model parameters and the possibility of visualizing the electrical behaviour of the panel according to the irradiance and temperature. Let us note that a sensitivity of the algorithm at the optimal operating point was observed owing to the fact that a small variation of the optimal voltage value leads to a very great variation of the identified parameters values. With the identified model, we can develop algorithms of maximum power point tracking, and make simulations of a solar water pumping system.(Author)

  5. Verification of high-speed solar wind stream forecasts using operational solar wind models

    DEFF Research Database (Denmark)

    Reiss, Martin A.; Temmer, Manuela; Veronig, Astrid M.

    2016-01-01

    and the background solar wind conditions. We found that both solar wind models are capable of predicting the large-scale features of the observed solar wind speed (root-mean-square error, RMSE ≈100 km/s) but tend to either overestimate (ESWF) or underestimate (WSA) the number of high-speed solar wind streams (threat......High-speed solar wind streams emanating from coronal holes are frequently impinging on the Earth's magnetosphere causing recurrent, medium-level geomagnetic storm activity. Modeling high-speed solar wind streams is thus an essential element of successful space weather forecasting. Here we evaluate...... high-speed stream forecasts made by the empirical solar wind forecast (ESWF) and the semiempirical Wang-Sheeley-Arge (WSA) model based on the in situ plasma measurements from the Advanced Composition Explorer (ACE) spacecraft for the years 2011 to 2014. While the ESWF makes use of an empirical relation...

  6. Models for efficient integration of solar energy

    DEFF Research Database (Denmark)

    Bacher, Peder

    the available flexibility in the system. In the present thesis methods related to operation of solar energy systems and for optimal energy use in buildings are presented. Two approaches for forecasting of solar power based on numerical weather predictions (NWPs) are presented, they are applied to forecast......Efficient operation of energy systems with substantial amount of renewable energy production is becoming increasingly important. Renewables are dependent on the weather conditions and are therefore by nature volatile and uncontrollable, opposed to traditional energy production based on combustion....... The "smart grid" is a broad term for the technology for addressing the challenge of operating the grid with a large share of renewables. The "smart" part is formed by technologies, which models the properties of the systems and efficiently adapt the load to the volatile energy production, by using...

  7. DESIGN AND ANALYSIS OF THE SNS CCL HOT MODEL WATER COOLING SYSTEM USING THE SINDA/FLUINT NETWORK MODELING TOOL

    Energy Technology Data Exchange (ETDEWEB)

    C. AMMERMAN; J. BERNARDIN

    1999-11-01

    This report presents results for design and analysis of the hot model water cooling system for the Spallation Neutron Source (SNS) coupled-cavity linac (CCL). The hot model, when completed, will include segments for both the CCL and coupled-cavity drift-tube linac (CCDTL). The scope of this report encompasses the modeling effort for the CCL portion of the hot model. This modeling effort employed the SINDA/FLUINT network modeling tool. This report begins with an introduction of the SNS hot model and network modeling using SINDA/FLUINT. Next, the development and operation of the SINDA/FLUINT model are discussed. Finally, the results of the SINDA/FLUINT modeling effort are presented and discussed.

  8. A temperature dependent cyclic plasticity model for hot work tool steel including particle coarsening

    Science.gov (United States)

    Jilg, Andreas; Seifert, Thomas

    2018-05-01

    Hot work tools are subjected to complex thermal and mechanical loads during hot forming processes. Locally, the stresses can exceed the material's yield strength in highly loaded areas as e.g. in small radii in die cavities. To sustain the high loads, the hot forming tools are typically made of martensitic hot work steels. While temperatures for annealing of the tool steels usually lie in the range between 400 and 600 °C, the steels may experience even higher temperatures during hot forming, resulting in softening of the material due to coarsening of strengthening particles. In this paper, a temperature dependent cyclic plasticity model for the martensitic hot work tool steel 1.2367 (X38CrMoV5-3) is presented that includes softening due to particle coarsening and that can be applied in finite-element calculations to assess the effect of softening on the thermomechanical fatigue life of hot work tools. To this end, a kinetic model for the evolution of the mean size of secondary carbides based on Ostwald ripening is coupled with a cyclic plasticity model with kinematic hardening. Mechanism-based relations are developed to describe the dependency of the mechanical properties on carbide size and temperature. The material properties of the mechanical and kinetic model are determined on the basis of tempering hardness curves as well as monotonic and cyclic tests.

  9. Evaluation of the ENVI-Met Vegetation Model of Four Common Tree Species in a Subtropical Hot-Humid Area

    Directory of Open Access Journals (Sweden)

    Zhixin Liu

    2018-05-01

    Full Text Available Urban trees can significantly improve the outdoor thermal environment, especially in subtropical zones. However, due to the lack of fundamental evaluations of numerical simulation models, design and modification strategies for optimizing the thermal environment in subtropical hot-humid climate zones cannot be proposed accurately. To resolve this issue, this study investigated the physiological parameters (leaf surface temperature and vapor flux and thermal effects (solar radiation, air temperature, and humidity of four common tree species (Michelia alba, Mangifera indica, Ficus microcarpa, and Bauhinia blakeana in both spring and summer in Guangzhou, China. A comprehensive comparison of the observed and modeled data from ENVI-met (v4.2 Science, a three-dimensional microclimate model was performed. The results show that the most fundamental weakness of ENVI-met is the limitation of input solar radiation, which cannot be input hourly in the current version and may impact the thermal environment in simulation. For the tree model, the discrepancy between modeled and observed microclimate parameters was acceptable. However, for the physiological parameters, ENVI-met tended to overestimate the leaf surface temperature and underestimate the vapor flux, especially at midday in summer. The simplified calculation of the tree model may be one of the main reasons. Furthermore, the thermal effect of trees, meaning the differences between nearby treeless sites and shaded areas, were all underestimated in ENVI-met for each microclimate variable. This study shows that the tree model is suitable in subtropical hot-humid climates, but also needs some improvement.

  10. Effect of solar radiation on the performance of cross flow wet cooling tower in hot climate of Iran

    Science.gov (United States)

    Banooni, Salem; Chitsazan, Ali

    2016-11-01

    In some cities such as Ahvaz-Iran, the solar radiation is very high and the annual-mean-daily of the global solar radiation is about 17.33 MJ m2 d-1. Solar radiation as an external heat source seems to affect the thermal performance of the cooling towers. Usually, in modeling cooling tower, the effects of solar radiation are ignored. To investigate the effect of sunshade on the performance and modeling of the cooling tower, the experiments were conducted in two different states, cooling towers with and without sunshade. In this study, the Merkel's approach and finite difference technique are used to predict the thermal behavior of cross flow wet cooling tower without sunshade and the results are compared with the data obtained from the cooling towers with and without sunshade. Results showed that the sunshade is very efficient and it reduced the outlet water temperature, the approach and the water exergy of the cooling tower up to 1.2 °C, 15 and 1.1 %, respectively and increased the range and the efficiency of the cooling tower up to 29 and 37 %, respectively. Also, the sunshade decreased the error between the experimental data of the cooling tower with sunshade and the modeling results of the cooling tower without sunshade 1.85 % in average.

  11. Hot money and China's stock market volatility: Further evidence using the GARCH-MIDAS model

    Science.gov (United States)

    Wei, Yu; Yu, Qianwen; Liu, Jing; Cao, Yang

    2018-02-01

    This paper investigates the influence of hot money on the return and volatility of the Chinese stock market using a nonlinear Granger causality test and a new GARCH-class model based on mixed data sampling regression (GARCH-MIDAS). The empirical results suggest that no linear or nonlinear causality exists between the growth rate of hot money and the Chinese stock market return, implying that the Chinese stock market is not driven by hot money and vice versa. However, hot money has a significant positive impact on the long-term volatility of the Chinese stock market. Furthermore, the dependence between the long-term volatility caused by hot money and the total volatility of the Chinese stock market is time-variant, indicating that huge volatilities in the stock market are not always triggered by international speculation capital flow and that Chinese authorities should further focus on more systemic reforms in the trading rules and on effectively regulating the stock market.

  12. Computational Fluid Dynamics Model for Solar Thermal Storage Tanks with Helical Jacket Heater and Upper Spiral Coil Heater

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Seung Man [Seoul Nat' l Univ., Seoul (Korea, Republic of); Zhong, Yiming; Nam, Jin Hyun [Daegu Univ., Daegu (Korea, Republic of); Chung, Jae Dong [Sejong Univ., Seoul (Korea, Republic of); Hong, Hiki [Kyung Hee Univ., Seoul (Korea, Republic of)

    2013-04-15

    In a solar domestic hot water (Shadow) system, solar energy is collected using collector panels, transferred to a circulating heat transfer fluid (brine), and eventually stored in a thermal storage tank (Test) as hot water. In this study, a computational fluid dynamics (CAD) model was developed to predict the solar thermal energy storage in a hybrid type Test equipped with a helical jacket heater (mantle heat exchanger) and an immersed spiral coil heater. The helical jacket heater, which is the brine flow path attached to the side wall of a Test, has advantages including simple system design, low brine flow rate, and enhanced thermal stratification. In addition, the spiral coil heater further enhances the thermal performance and thermal stratification of the Test. The developed model was validated by the good agreement between the CAD results and the experimental results performed with the hybrid-type Test in Shadow settings.

  13. Computational Fluid Dynamics Model for Solar Thermal Storage Tanks with Helical Jacket Heater and Upper Spiral Coil Heater

    International Nuclear Information System (INIS)

    Baek, Seung Man; Zhong, Yiming; Nam, Jin Hyun; Chung, Jae Dong; Hong, Hiki

    2013-01-01

    In a solar domestic hot water (Shadow) system, solar energy is collected using collector panels, transferred to a circulating heat transfer fluid (brine), and eventually stored in a thermal storage tank (Test) as hot water. In this study, a computational fluid dynamics (CAD) model was developed to predict the solar thermal energy storage in a hybrid type Test equipped with a helical jacket heater (mantle heat exchanger) and an immersed spiral coil heater. The helical jacket heater, which is the brine flow path attached to the side wall of a Test, has advantages including simple system design, low brine flow rate, and enhanced thermal stratification. In addition, the spiral coil heater further enhances the thermal performance and thermal stratification of the Test. The developed model was validated by the good agreement between the CAD results and the experimental results performed with the hybrid-type Test in Shadow settings

  14. Experimental evidence of hot carriers solar cell operation in multi-quantum wells heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Rodière, Jean; Lombez, Laurent, E-mail: laurent.lombez@chimie-paristech.fr [IRDEP, Institute of R and D on Photovoltaic Energy, UMR 7174, CNRS-EDF-Chimie ParisTech, 6 Quai Watier-BP 49, 78401 Chatou Cedex (France); Le Corre, Alain; Durand, Olivier [INSA, FOTON-OHM, UMR 6082, F-35708 Rennes (France); Guillemoles, Jean-François [IRDEP, Institute of R and D on Photovoltaic Energy, UMR 7174, CNRS-EDF-Chimie ParisTech, 6 Quai Watier-BP 49, 78401 Chatou Cedex (France); NextPV, LIA CNRS-RCAST/U. Tokyo-U. Bordeaux, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan)

    2015-05-04

    We investigated a semiconductor heterostructure based on InGaAsP multi quantum wells (QWs) using optical characterizations and demonstrate its potential to work as a hot carrier cell absorber. By analyzing photoluminescence spectra, the quasi Fermi level splitting Δμ and the carrier temperature are quantitatively measured as a function of the excitation power. Moreover, both thermodynamics values are measured at the QWs and the barrier emission energy. High values of Δμ are found for both transition, and high carrier temperature values in the QWs. Remarkably, the quasi Fermi level splitting measured at the barrier energy exceeds the absorption threshold of the QWs. This indicates a working condition beyond the classical Shockley-Queisser limit.

  15. Modeling of Possible Conditions for Origin of First Organic Forms in hot Mineral Water

    OpenAIRE

    Ignat Ignatov; Oleg Mosin

    2014-01-01

    The composition of water, its temperature and pH value was analyzed in experiments with modelling of primary hydrosphere and possible conditions for origin of first organic forms in hot mineral water. For this aim the authors performed experiments with hot mineral and seawater from Bulgaria by IR-spectrometry (DNES-method). As model systems were used cactus juice of Echinopsis pachanoi and Mediterranean jellyfish Cotylorhiza tuberculata. It was considered the reactions of condensation and deh...

  16. Solar Technology Curriculum, 1980.

    Science.gov (United States)

    Seward County Community Coll., Liberal, KS.

    This curriculum guide contains lecture outlines and handouts for training solar technicians in the installation, maintenance, and repair of solar energy hot water and space heating systems. The curriculum consists of four modular units developed to provide a model through which community colleges and area vocational/technical schools can respond…

  17. Elementary Students' Mental Models of the Solar System

    Science.gov (United States)

    Calderon-Canales, Elena; Flores-Camacho, Fernando; Gallegos-Cazares, Leticia

    2013-01-01

    This research project aimed to identify and analyze Mexican primary school students' ideas about the components of the solar system. In particular, this study focused on conceptions of the solar system and representations of the dynamics of the solar system based on the functional and structural models that students make in school. Using a…

  18. Comparison of solar panel models for grid integration studies

    NARCIS (Netherlands)

    Brito, E.M.S.; Cupertino, A.F.; Carlette, L.P; Filho, D.O.; Oliveira, D.; Pereira, H.A; Ribeiro, P.F.

    2012-01-01

    Photovoltaic systems are highly dependent on climatic conditions in which they are submitted. The incident solar irradiance and temperature are the main factors impacting on the power generated by a solar panel. This paper presents three different models of a solar panel and compare, through

  19. Model validation studies of solar systems, Phase III. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lantz, L.J.; Winn, C.B.

    1978-12-01

    Results obtained from a validation study of the TRNSYS, SIMSHAC, and SOLCOST solar system simulation and design are presented. Also included are comparisons between the FCHART and SOLCOST solar system design programs and some changes that were made to the SOLCOST program. Finally, results obtained from the analysis of several solar radiation models are presented. Separate abstracts were prepared for ten papers.

  20. Modeling and analysis of solar distributed generation

    Science.gov (United States)

    Ortiz Rivera, Eduardo Ivan

    Recent changes in the global economy are creating a big impact in our daily life. The price of oil is increasing and the number of reserves are less every day. Also, dramatic demographic changes are impacting the viability of the electric infrastructure and ultimately the economic future of the industry. These are some of the reasons that many countries are looking for alternative energy to produce electric energy. The most common form of green energy in our daily life is solar energy. To convert solar energy into electrical energy is required solar panels, dc-dc converters, power control, sensors, and inverters. In this work, a photovoltaic module, PVM, model using the electrical characteristics provided by the manufacturer data sheet is presented for power system applications. Experimental results from testing are showed, verifying the proposed PVM model. Also in this work, three maximum power point tracker, MPPT, algorithms would be presented to obtain the maximum power from a PVM. The first MPPT algorithm is a method based on the Rolle's and Lagrange's Theorems and can provide at least an approximate answer to a family of transcendental functions that cannot be solved using differential calculus. The second MPPT algorithm is based on the approximation of the proposed PVM model using fractional polynomials where the shape, boundary conditions and performance of the proposed PVM model are satisfied. The third MPPT algorithm is based in the determination of the optimal duty cycle for a dc-dc converter and the previous knowledge of the load or load matching conditions. Also, four algorithms to calculate the effective irradiance level and temperature over a photovoltaic module are presented in this work. The main reasons to develop these algorithms are for monitoring climate conditions, the elimination of temperature and solar irradiance sensors, reductions in cost for a photovoltaic inverter system, and development of new algorithms to be integrated with maximum

  1. The Fate of Cool Material in the Hot Corona: Solar Prominences and Coronal Rain

    Science.gov (United States)

    Liu, Wei; Antolin, Patrick; Sun, Xudong; Vial, Jean-Claude; Berger, Thomas

    2017-08-01

    As an important chain of the chromosphere-corona mass cycle, some of the million-degree hot coronal mass undergoes a radiative cooling instability and condenses into material at chromospheric or transition-region temperatures in two distinct forms - prominences and coronal rain (some of which eventually falls back to the chromosphere). A quiescent prominence usually consists of numerous long-lasting, filamentary downflow threads, while coronal rain consists of transient mass blobs falling at comparably higher speeds along well-defined paths. It remains puzzling why such material of similar temperatures exhibit contrasting morphologies and behaviors. We report recent SDO/AIA and IRIS observations that suggest different magnetic environments being responsible for such distinctions. Specifically, in a hybrid prominence-coronal rain complex structure, we found that the prominence material is formed and resides near magnetic null points that favor the radiative cooling process and provide possibly a high plasma-beta environment suitable for the existence of meandering prominence threads. As the cool material descends, it turns into coronal rain tied onto low-lying coronal loops in a likely low-beta environment. Such structures resemble to certain extent the so-called coronal spiders or cloud prominences, but the observations reported here provide critical new insights. We will discuss the broad physical implications of these observations for fundamental questions, such as coronal heating and beyond (e.g., in astrophysical and/or laboratory plasma environments).

  2. ANALYSIS OF MEASURED AND MODELED SOLAR RADIATION AT THE TARS SOLAR HEATING PLANT IN DENMARK

    DEFF Research Database (Denmark)

    Tian, Zhiyong; Perers, Bengt; Furbo, Simon

    2017-01-01

    , such as solar radiation, inlet and outlet temperature for the solar collector field, flow rate and pressure, ambient temperature, Wind speed and wind direction were measured. Global horizontal radiation, direct normal irradiation (DNI) and total radiation on the tilted collector plane of the flat plate...... collector field have been measured in Tars solar heating plant. To determine the accuracy of modeled and measured solar radiation in Tars solar heating plant, monthly comparisons of measured and calculated radiation using 6 empirical models have been carried out. Comparisons of measured and modeled total......A novel combined solar heating plant with tracking parabolic trough collectors (PTC) and flat plate collectors (FPC) has been constructed and put into operation in Tars, 30 km north of Aalborg, Denmark in August 2015. To assess the operation performance of the plant, detailed parameters...

  3. Thermal Modeling of a Hybrid Thermoelectric Solar Collector with a Compound Parabolic Concentrator

    Science.gov (United States)

    Lertsatitthanakorn, C.; Jamradloedluk, J.; Rungsiyopas, M.

    2013-07-01

    In this study radiant light from the sun is used by a hybrid thermoelectric (TE) solar collector and a compound parabolic concentrator (CPC) to generate electricity and thermal energy. The hybrid TE solar collector system described in this report is composed of transparent glass, an air gap, an absorber plate, TE modules, a heat sink to cool the water, and a storage tank. Incident solar radiation falls on the CPC, which directs and reflects the radiation to heat up the absorber plate, creating a temperature difference across the TE modules. The water, which absorbs heat from the hot TE modules, flows through the heat sink to release its heat. The results show that the electrical power output and the conversion efficiency depend on the temperature difference between the hot and cold sides of the TE modules. A maximum power output of 1.03 W and a conversion efficiency of 0.6% were obtained when the temperature difference was 12°C. The thermal efficiency increased as the water flow rate increased. The maximum thermal efficiency achieved was 43.3%, corresponding to a water flow rate of 0.24 kg/s. These experimental results verify that using a TE solar collector with a CPC to produce both electrical power and thermal energy seems to be feasible. The thermal model and calculation method can be applied for performance prediction.

  4. Modelling radiative heat transfer inside a basin type solar still

    International Nuclear Information System (INIS)

    Madhlopa, A.

    2014-01-01

    Radiative heat transfer inside a basin type solar still has been investigated using two models with (model 1) and without (model 2) taking into account optical view factors. The coefficient of radiative heat exchange (h r,w-gc ) between the water and cover surfaces of a practical solar still was computed using the two models. Simulation results show that model 1 yields lower values of h r,w-gc and the root mean square error than model 2. It is therefore concluded that the accuracy of modelling the performance of a basin-type solar still can be improved by incorporating view factors. - Highlights: • Radiative heat transfer in a basin type solar still has been investigated. • Two models with and without view factors were used. • The model with view factors exhibits a lower magnitude of root mean square error. • View factors affect the accuracy of modelling the performance of the solar still

  5. Study of solar radiation prediction and modeling of relationships between solar radiation and meteorological variables

    International Nuclear Information System (INIS)

    Sun, Huaiwei; Zhao, Na; Zeng, Xiaofan; Yan, Dong

    2015-01-01

    Highlights: • We investigate relationships between solar radiation and meteorological variables. • A strong relationship exists between solar radiation and sunshine duration. • Daily global radiation can be estimated accurately with ARMAX–GARCH models. • MGARCH model was applied to investigate time-varying relationships. - Abstract: The traditional approaches that employ the correlations between solar radiation and other measured meteorological variables are commonly utilized in studies. It is important to investigate the time-varying relationships between meteorological variables and solar radiation to determine which variables have the strongest correlations with solar radiation. In this study, the nonlinear autoregressive moving average with exogenous variable–generalized autoregressive conditional heteroscedasticity (ARMAX–GARCH) and multivariate GARCH (MGARCH) time-series approaches were applied to investigate the associations between solar radiation and several meteorological variables. For these investigations, the long-term daily global solar radiation series measured at three stations from January 1, 2004 until December 31, 2007 were used in this study. Stronger relationships were observed to exist between global solar radiation and sunshine duration than between solar radiation and temperature difference. The results show that 82–88% of the temporal variations of the global solar radiation were captured by the sunshine-duration-based ARMAX–GARCH models and 55–68% of daily variations were captured by the temperature-difference-based ARMAX–GARCH models. The advantages of the ARMAX–GARCH models were also confirmed by comparison of Auto-Regressive and Moving Average (ARMA) and neutral network (ANN) models in the estimation of daily global solar radiation. The strong heteroscedastic persistency of the global solar radiation series was revealed by the AutoRegressive Conditional Heteroscedasticity (ARCH) and Generalized Auto

  6. Breakdown of hot-spot model in determining convective amplification in large homogeneous systems

    International Nuclear Information System (INIS)

    Mounaix, Philippe; Divol, Laurent

    2004-01-01

    Convective amplification in large homogeneous systems is studied, both analytically and numerically, in the case of a linear diffraction-free stochastic amplifier. Overall amplification does not result from successive amplifications in small scale high intensity hot spots, but from a single amplification in a delocalized mode of the driver field spreading over the whole interaction length. For this model, the hot-spot approach is found to systematically underestimate the gain factor by more than 50%

  7. Theoretical modelling of solar dish concentrator

    International Nuclear Information System (INIS)

    Yaaseen Rafeeu; Mohd Zainal Abidin Abdul Kadir; Senan Mohamed Abdulla; Nor Mariah Adam

    2009-01-01

    Full text: Concentrating solar power (CSP) technologies could be one of the major contributor to worlds future energy needs and which would be cheap and clean sources of energy. This would improve energy utilization, higher conversion efficiency with reliable and affordable supply of electricity to the public. The proposed approach is using different size and depth of solar dish concentrators to improve solar fraction using the aluminium foil as reflector. In this paper, different measurement of solar concentrators is investigated and aims to aims to introducing an improved methodology for solar fraction on incoming solar energy in wet climate. (author)

  8. An update of Leighton's solar dynamo model

    Science.gov (United States)

    Cameron, R. H.; Schüssler, M.

    2017-03-01

    In 1969, Leighton developed a quasi-1D mathematical model of the solar dynamo, building upon the phenomenological scenario of Babcock published in 1961. Here we present a modification and extension of Leighton's model. Using the axisymmetric component (longitudinal average) of the magnetic field, we consider the radial field component at the solar surface and the radially integrated toroidal magnetic flux in the convection zone, both as functions of latitude. No assumptions are made with regard to the radial location of the toroidal flux. The model includes the effects of (I) turbulent diffusion at the surface and in the convection zone; (II) poleward meridional flow at the surface and an equatorward return flow affecting the toroidal flux; (III) latitudinal differential rotation and the near-surface layer of radial rotational shear; (iv) downward convective pumping of magnetic flux in the shear layer; and (v) flux emergence in the form of tilted bipolar magnetic regions treated as a source term for the radial surface field. While the parameters relevant for the transport of the surface field are taken from observations, the model condenses the unknown properties of magnetic field and flow in the convection zone into a few free parameters (turbulent diffusivity, effective return flow, amplitude of the source term, and a parameter describing the effective radial shear). Comparison with the results of 2D flux transport dynamo codes shows that the model captures the essential features of these simulations. We make use of the computational efficiency of the model to carry out an extended parameter study. We cover an extended domain of the 4D parameter space and identify the parameter ranges that provide solar-like solutions. Dipole parity is always preferred and solutions with periods around 22 yr and a correct phase difference between flux emergence in low latitudes and the strength of the polar fields are found for a return flow speed around 2 m s-1, turbulent

  9. A Model for Hourly Solar Radiation Data Generation from Daily Solar Radiation Data Using a Generalized Regression Artificial Neural Network

    OpenAIRE

    Khatib, Tamer; Elmenreich, Wilfried

    2015-01-01

    This paper presents a model for predicting hourly solar radiation data using daily solar radiation averages. The proposed model is a generalized regression artificial neural network. This model has three inputs, namely, mean daily solar radiation, hour angle, and sunset hour angle. The output layer has one node which is mean hourly solar radiation. The training and development of the proposed model are done using MATLAB and 43800 records of hourly global solar radiation. The results show that...

  10. A feature-based approach to modeling protein–protein interaction hot spots

    Science.gov (United States)

    Cho, Kyu-il; Kim, Dongsup; Lee, Doheon

    2009-01-01

    Identifying features that effectively represent the energetic contribution of an individual interface residue to the interactions between proteins remains problematic. Here, we present several new features and show that they are more effective than conventional features. By combining the proposed features with conventional features, we develop a predictive model for interaction hot spots. Initially, 54 multifaceted features, composed of different levels of information including structure, sequence and molecular interaction information, are quantified. Then, to identify the best subset of features for predicting hot spots, feature selection is performed using a decision tree. Based on the selected features, a predictive model for hot spots is created using support vector machine (SVM) and tested on an independent test set. Our model shows better overall predictive accuracy than previous methods such as the alanine scanning methods Robetta and FOLDEF, and the knowledge-based method KFC. Subsequent analysis yields several findings about hot spots. As expected, hot spots have a larger relative surface area burial and are more hydrophobic than other residues. Unexpectedly, however, residue conservation displays a rather complicated tendency depending on the types of protein complexes, indicating that this feature is not good for identifying hot spots. Of the selected features, the weighted atomic packing density, relative surface area burial and weighted hydrophobicity are the top 3, with the weighted atomic packing density proving to be the most effective feature for predicting hot spots. Notably, we find that hot spots are closely related to π–related interactions, especially π · · · π interactions. PMID:19273533

  11. Modelling of Box Type Solar Cooker Performance in a Tropical ...

    African Journals Online (AJOL)

    Thermal performance model of box type solar cooker with loaded water is presented. The model was developed using the method of Funk to estimate cooking power in terms of climatic and design parameters for box type solar cooker in a tropical environment. Coefficients for each term used in the model were determined ...

  12. The choice between cooled tubular reactor models: analysis of the hot spot

    NARCIS (Netherlands)

    Westerink, E.J.; Koster, N.; Westerterp, K.R.

    1990-01-01

    The applicability of the one-dimensional pseudo-homogeneous model of the cooled tubular reactor is studied. Using the two-dimensional model as the more accurate one we compared both models by studying the influence of the design and operating variables on the conditions in the hot spot of the

  13. Numerical modelling of multi-pass solar dryer filled with granite pebbles for thermal storage enhancement

    International Nuclear Information System (INIS)

    Kareem, M W; Habib, K; Ruslan, M H

    2015-01-01

    In this paper, a theoretical modelling of a cheap solar thermal dryer for small and medium scale farmers with multi-pass approach has been investigated. Comsol Multiphysics modelling tool was employed using numerical technique. The rock particles were used to enhance the thermal storage of the drying system. The local weather data were used during the simulation while parameters and coefficients were sourced from literature. An improvement on efficiency of up to 7% was recorded with error of 10 -5 when compared with the reported double pass solar collector. A fair distribution of hot air within the cabinets was also achieved. Though the modelling tool used was robust but the characterization of the system materials need to be done to improve the system accuracy and better prediction. (paper)

  14. Measurement and modelling of a multifunctional solar plus heatpump system from Nilan

    DEFF Research Database (Denmark)

    Perers, Bengt; Andersen, Elsa; Furbo, Simon

    A multifunctional solar and heat pump unit from Nilan has been installed in the Performance Test Facility (PTF) at DTU Byg Denmark. It is part of the IEA Task 44 cooperation. Multifunctional means in this case: Hot water, Air heating, Ventilation, Air heat recovery, Air filtering and Floor heating....... Nilan units, with additional air cooling and CO2 control, are also available. The unit has been in operation for more than one year. The aim has been to stress the system operation to different conditions in the lab, to learn more about the performance, but also to find possible improvements especially...... concerning advanced control. The operation into extreme states of high hot water demand and low air ventilation rates, has also been done to develop and validate a TRNSYS system model. The model was developed and validated for the first period of operation mainly winter and early spring conditions. Now...

  15. Modeling Skin Injury from Hot Rice Porridge Spills

    Directory of Open Access Journals (Sweden)

    Torgrim Log

    2018-04-01

    Full Text Available The present work analyzes skin burns from spills of hot rice and milk products. The traditional Norwegian rice porridge serves as an example. By testing spills on objects emulating an arm, it was concluded that spills were seldom thinner than 3 mm, and stayed in place due to the viscosity of the porridge for more than one minute. The Pennes bioheat equation was solved numerically for such spills, including heat conduction to the skin and convective heat losses from the porridge surface. Temperatures were analyzed in the porridge and skin layers, and the resulting skin injury was calculated based on the basal layer temperature. Parameters influencing burn severity, such as porridge layer thickness, porridge temperature, removal of the porridge and thermal effects of post scald tempered (15 °C water cooling were analyzed. The spilled porridge resulted in a prolonged heat supply to the skin, and the skin injury developed significantly with time. The porridge temperature turned out to be the most important injury parameter. A 70 °C porridge temperature could develop superficial partial-thickness burns. Porridge temperatures at processing temperatures nearly instantly developed severe burns. It was demonstrated that prompt removal of the hot porridge significantly reduced the injury development. The general advice is to avoid serving porridge and similar products at temperatures above 65 °C and, if spilled on the skin, to remove it quickly. After such scald incidents, it is advised to cool the injured area by tempered water for a prolonged period to stimulate healing.

  16. [The interaction of soil micromycetes with "hot" particles in a model system].

    Science.gov (United States)

    Zhdanova, N N; Lashko, T N; Redchits, T I; Vasilevskaia, A I; Borisiuk, L G; Siniavskaia, O I; Gavriliuk, V I; Muzalev, P N

    1991-01-01

    A model system which permits observing for a long time and fixing interaction of fungi with a radiation source has been created on the basis of an isolated "hot" particle, deficient mineral medium (saccharose content 60 mg/l) and suspension of fungal conidia. Five species (six strains) of micromycetes isolated from radionuclide-contaminated soils and fifteen "hot" particles have been tested. It has been found out for the first time that Cladosporium cladosporioides and Penicillium roseo-purpureum are able actively overgrow "hot" particles whose radioactivity did not exceed 3.1-1.0(-7) Ci by gamma-spectrum and to destroy them 50-150 days later. Certain changes in morphology of fungi-destructors of "hot" particles are revealed. A problem on ecological significance of the found phenomenon is discussed.

  17. Optimal operation by dynamic programming in a solar/electric hot-water system; Taiyonetsu/denryoku kyuto system no doteki keikakuho ni yoru saiteki un`yo

    Energy Technology Data Exchange (ETDEWEB)

    Edo, S; Kenmoku, Y; Sakakibara, T [Toyohashi University of Technology, Aichi (Japan); Nakagawa, S [Maizuru College of Technology, Kyoto (Japan); Kawamoto, T [Shizuoka University, Shizuoka (Japan)

    1997-11-25

    With regard to utilization of a solar/electric hot-water system, a discussion was given by using a dynamic programming method on operation of a system which minimizes power charge. The discussed system is an installation in a welfare facility accommodating 100 persons, where solar heat is stored in a heat storage tank from a heat collector, and utilized for hot water supply. If the solar heat is insufficient for required hot water quantity, the water is heated by using an electric heater. The discussion compared the system operation using the dynamic programming method with the following two systems: the operation method 1, which does not utilize insolation forecast and the operation method 2, in which insolation forecast is utilized and late-night electric power is utilized for heating water in shortage. As a result of the calculation, the operation using the dynamic programming method conducts heat storage by utilizing the late-night power even if insolation is sufficient in winter in order to suppress heating by utilizing late-night power for days with less insolation. Thus, suppression is given on excessive utilization of day-time power and on rise in annual maximum power demand. It was found that the present system reduces power consumption by 37.7% when compared with the operation method 1, and 22.7% when compared even with the operation method 2. 3 refs., 5 figs., 3 tabs.

  18. Solar Radiation Model for Development and Control of Solar Energy Sources

    Directory of Open Access Journals (Sweden)

    Dominykas Vasarevičius

    2016-06-01

    Full Text Available The model of solar radiation, which takes into account direct, diffused and reflected components of solar energy, has been presented. Model is associated with geographical coordinates and local time of every day of the year. It is shown that using analytic equations for modelling the direct component, it is possible to adopt it for embedded systems with low computational power and use in solar tracking applications. Reflected and diffused components are especially useful in determining the performance of photovoltaic modules in certain location and surroundings. The statistical method for cloud layer simulation based on local meteorological data is offered. The presented method can’t be used for prediction of weather conditions but it provides patterns of solar radiation in time comparable to those measured with pyranometer. Cloud layer simulation together with total solar radiation model is a useful tool for development and analysis of maximum power point tracking controllers for PV modules.

  19. Experimental analysis of solar thermal integrated MD system for cogeneration of drinking water and hot water for single family villa in dubai using flat plate and evacuated tube solar collectors

    DEFF Research Database (Denmark)

    Asim, Muhammad; Imran, Muhammad; Leung, Michael K.H.

    2017-01-01

    This paper presents the experimental analysis performed on solar thermal integrated membrane distillation (MD) system using flat plate and evacuated tube collectors. The system will be utilized for cogeneration of drinking water and domestic hot water for single family in Dubai comprising of four...... to five members. Experiments have been performed in Ras Al Khaimah Research and Innovation Centre (RAKRIC) facility. The experimental setup has been installed to achieve the required production of 15–25 L/d of drinking water and 250 L/d of hot water for domestic purposes. Experiments have been performed...

  20. Prediction of hot spots in protein interfaces using a random forest model with hybrid features.

    Science.gov (United States)

    Wang, Lin; Liu, Zhi-Ping; Zhang, Xiang-Sun; Chen, Luonan

    2012-03-01

    Prediction of hot spots in protein interfaces provides crucial information for the research on protein-protein interaction and drug design. Existing machine learning methods generally judge whether a given residue is likely to be a hot spot by extracting features only from the target residue. However, hot spots usually form a small cluster of residues which are tightly packed together at the center of protein interface. With this in mind, we present a novel method to extract hybrid features which incorporate a wide range of information of the target residue and its spatially neighboring residues, i.e. the nearest contact residue in the other face (mirror-contact residue) and the nearest contact residue in the same face (intra-contact residue). We provide a novel random forest (RF) model to effectively integrate these hybrid features for predicting hot spots in protein interfaces. Our method can achieve accuracy (ACC) of 82.4% and Matthew's correlation coefficient (MCC) of 0.482 in Alanine Scanning Energetics Database, and ACC of 77.6% and MCC of 0.429 in Binding Interface Database. In a comparison study, performance of our RF model exceeds other existing methods, such as Robetta, FOLDEF, KFC, KFC2, MINERVA and HotPoint. Of our hybrid features, three physicochemical features of target residues (mass, polarizability and isoelectric point), the relative side-chain accessible surface area and the average depth index of mirror-contact residues are found to be the main discriminative features in hot spots prediction. We also confirm that hot spots tend to form large contact surface areas between two interacting proteins. Source data and code are available at: http://www.aporc.org/doc/wiki/HotSpot.

  1. The Pore Collapse “Hot-Spots” Model Coupled with Brittle Damage for Solid Explosives

    Directory of Open Access Journals (Sweden)

    L. R. Cheng

    2014-01-01

    Full Text Available This paper is devoted to the building of a numerical pore collapse model with “hot-spots” formation for the impacted damage explosives. According to damage mechanical evolution of brittle material, the one-dimensional elastic-viscoplastic collapse model was improved to incorporate the impact damage during the dynamic collapse of pores. The damage of explosives was studied using the statistical crack mechanics (SCRAM. The effects of the heat conduction and the chemical reaction were taken into account in the formation of “hot-spots.” To verify the improved model, numerical simulations were carried out for different pressure states and used to model a multiple-impact experiment. The results show that repeated weak impacts can lead to the collapse of pores and the “hot-spots” may occur due to the accumulation of internal defects accompanied by the softening of explosives.

  2. Solar Coronal Jets: Observations, Theory, and Modeling

    Science.gov (United States)

    Raouafi, N. E.; Patsourakos, S.; Pariat, E.; Young, P. R.; Sterling, A.; Savcheva, A.; Shimojo, M.; Moreno-Insertis, F.; Devore, C. R.; Archontis, V.; hide

    2016-01-01

    Chromospheric and coronal jets represent important manifestations of ubiquitous solar transients, which may be the source of signicant mass and energy input to the upper solar atmosphere and the solar wind. While the energy involved in a jet-like event is smaller than that of nominal solar ares and Coronal Mass Ejections (CMEs), jets share many common properties with these major phenomena, in particular, the explosive magnetically driven dynamics. Studies of jets could, therefore, provide critical insight for understanding the larger, more complex drivers of the solar activity. On the other side of the size-spectrum, the study of jets could also supply important clues on the physics of transients closeor at the limit of the current spatial resolution such as spicules. Furthermore, jet phenomena may hint to basic process for heating the corona and accelerating the solar wind; consequently their study gives us the opportunity to attack a broadrange of solar-heliospheric problems.

  3. FY 1977 Annual report on Sunshine Project results. Research and development of solar energy systems for air conditioning and hot water supply (Research and development of solar systems for condominiums); 1977 nendo taiyo reidanbo oyobi kyuto system no kenkyu kaihatsu seika hokokusho. Shugo jutakuyo system no kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1978-06-01

    This project is aimed at technological development of economical solar energy systems for air conditioning and hot water supply for condominiums. The major items for the FY 1977 programs include (1) designs and fabrication of equipment for a test building, (2) development of the equipment materials, and (3) system analysis. The jobs for item (1) include management of the designs and construction, placing an order for the building, and fabrication of an air conditioner expander and heat pump; those for item (2) include simplification of a condensing type and plate type heat collector structures, weather-resistance of the plate type heat collector structure, and materials for selective absorbing membranes and reflectors; and those for item (3) include estimation of heat loads in a model building, first to third floors as the test building, and fourth to 14th floors as the conventional box-shaped building. The heat collector installation area is investigated for a multistory building, for which solar radiation intensity at the heat-receiving plane and the like are taken into account. It is found that the solar system can be installed, when an area of 50m{sup 2} can be allocated to the system in each story. There is a limit to story number for the solar system to economically work for air conditioning and hot water supply. Sufficient insulation of the system and reduction in pipe length by zoning are the necessary measures against heat losses. (NEDO)

  4. Determining the energy performance of manually controlled solar shades: A stochastic model based co-simulation analysis

    International Nuclear Information System (INIS)

    Yao, Jian

    2014-01-01

    Highlights: • Driving factor for adjustment of manually controlled solar shades was determined. • A stochastic model for manual solar shades was constructed using Markov method. • Co-simulation with Energyplus was carried out in BCVTB. • External shading even manually controlled should be used prior to LOW-E windows. • Previous studies on manual solar shades may overestimate energy savings. - Abstract: Solar shading devices play a significant role in reducing building energy consumption and maintaining a comfortable indoor condition. In this paper, a typical office building with internal roller shades in hot summer and cold winter zone was selected to determine the driving factor of control behavior of manual solar shades. Solar radiation was determined as the major factor in driving solar shading adjustment based on field measurements and logit analysis and then a stochastic model for manually adjusted solar shades was constructed by using Markov method. This model was used in BCVTB for further co-simulation with Energyplus to determine the impact of the control behavior of solar shades on energy performance. The results show that manually adjusted solar shades, whatever located inside or outside, have a relatively high energy saving performance than clear-pane windows while only external shades perform better than regularly used LOW-E windows. Simulation also indicates that using an ideal assumption of solar shade adjustment as most studies do in building simulation may lead to an overestimation of energy saving by about 16–30%. There is a need to improve occupants’ actions on shades to more effectively respond to outdoor conditions in order to lower energy consumption, and this improvement can be easily achieved by using simple strategies as a guide to control manual solar shades

  5. Phase fluctuations model for EM wave propagation through solar scintillation at superior solar conjunction

    Science.gov (United States)

    Xu, Guanjun; Song, Zhaohui

    2017-04-01

    Traveling solar wind disturbances have a significant influence on radio wave characteristics during the superior solar conjunction communication. This paper considers the impact of solar scintillation on phase fluctuations of electromagnetic (EM) wave propagation during the superior solar conjunction. Based on the Geometric Optics approximation, the close-form approximation model for phase fluctuations is developed. Both effects of anisotropic temporal variations function of plasma irregularities and their power spectrum are presented and analyzed numerically. It is found that phase fluctuations rapidly decrease with increasing Sun-Earth-Probe angle and decrease with increasing frequency at the rate of 1/f2. Moreover, the role of various features of the solar wind irregularities and their influence on the EM wave characteristic parameters is studied and discussed. Finally, we study the phase fluctuations of typical cases in order to better understand the impact of phase fluctuations in future deep space communication scenarios during solar conjunction periods.

  6. Modelling of Damage During Hot Forging of Ingots

    DEFF Research Database (Denmark)

    Christiansen, Peter; Hattel, Jesper Henri; Bay, Niels

    2013-01-01

    Ductile damage modelling in the ingot forging process is discussed. Advantages and disadvantages of both coupled and uncoupled ductile damage models are presented. Some uncoupled damage models are examined in greater detail regarding their applicability to different processes, where hydrostatic...

  7. Modeling Jovian Magnetospheres Beyond the Solar System

    Science.gov (United States)

    Williams, Peter K. G.

    2018-06-01

    Low-frequency radio observations are believed to represent one of the few means of directly probing the magnetic fields of extrasolar planets. However, a half-century of low-frequency planetary observations within the Solar System demonstrate that detailed, physically-motivated magnetospheric models are needed to properly interpret the radio data. I will present recent work in this area focusing on the current state of the art: relatively high-frequency observations of relatively massive objects, which are now understood to have magnetospheres that are largely planetary in nature. I will highlight the key challenges that will arise in future space-based observations of lower-mass objects at lower frequencies.

  8. Fiscal 1974 Sunshine Project result report. Research on solar cooling/heating and hot water supply system; 1974 nendo taiyonetsu reidanbo kyuto system no kenkyu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1975-03-01

    This report describes the fiscal 1974 research result on solar cooling/heating and hot water supply system. This 3- year project from fiscal 1974 to 1976 aims to predict the share of solar energy in future cooling/heating and hot water supply energy demand, and develop simulation technology. The project surveys and analyzes current domestic and overseas development states, and studies various systems to obtain characteristics of every system, pursuit an optimum implementation, and establish a diffusion plan. Future energy consumptions and prices are predicted in relation to energy saving, and the utilization impact of solar energy is analyzed. Study is also made on diffusion plan, profitability and performance evaluation method. Among these schedules, in fiscal 1974 based on the survey and analysis on previous domestic and overseas development states, features and problems were arranged every system and application. The basic study on system simulation, and rough feasibility study on solar heat systems by conventional technique were carried out. The basic data on performance evaluation standards were also prepared. (NEDO)

  9. Modelling and simulation of a hybrid solar heating system for greenhouse applications using Matlab/Simulink

    International Nuclear Information System (INIS)

    Kıyan, Metin; Bingöl, Ekin; Melikoğlu, Mehmet; Albostan, Ayhan

    2013-01-01

    Highlights: • Matlab/Simulink modelling of a solar hybrid greenhouse. • Estimation of greenhouse gas emission reductions. • Feasibility and cost analysis of the system. - Abstract: Solar energy is a major renewable energy source and hybrid solar systems are gaining increased academic and industrial attention due to the unique advantages they offer. In this paper, a mathematical model has been developed to investigate the thermal behavior of a greenhouse heated by a hybrid solar collector system. This hybrid system contains an evacuated tube solar heat collector unit, an auxiliary fossil fuel heating unit, a hot water storage unit, control and piping units. A Matlab/Simulink based model and software has been developed to predict the storage water temperature, greenhouse indoor temperature and the amount of auxiliary fuel, as a function of various design parameters of the greenhouse such as location, dimensions, and meteorological data of the region. As a case study, a greenhouse located in Şanlıurfa/Turkey has been simulated based on recent meteorological data and aforementioned hybrid system. The results of simulations performed on an annual basis indicate that revising the existing fossil fuel system with the proposed hybrid system, is economically feasible for most cases, however it requires a slightly longer payback period than expected. On the other hand, by reducing the greenhouse gas emissions significantly, it has a considerable positive environmental impact. The developed dynamic simulation method can be further used for designing heating systems for various solar greenhouses and optimizing the solar collector and thermal storage sizes

  10. Modelling of mid-infrared interferometric signature of hot exozodiacal dust emission

    Science.gov (United States)

    Kirchschlager, Florian; Wolf, Sebastian; Brunngräber, Robert; Matter, Alexis; Krivov, Alexander V.; Labdon, Aaron

    2018-01-01

    Hot exozodiacal dust emission was detected in recent surveys around two dozen main-sequence stars at distances of less than 1 au using the H- and K-band interferometry. Due to the high contrast as well as the small angular distance between the circumstellar dust and the star, direct observation of this dust component is challenging. An alternative way to explore the hot exozodiacal dust is provided by mid-infrared interferometry. We analyse the L, M and N bands interferometric signature of this emission in order to find stronger constraints for the properties and the origin of the hot exozodiacal dust. Considering the parameters of nine debris disc systems derived previously, we model the discs in each of these bands. We find that the M band possesses the best conditions to detect hot dust emission, closely followed by L and N bands. The hot dust in three systems - HD 22484 (10 Tau), HD 102647 (β Leo) and HD 177724 (ζ Aql) - shows a strong signal in the visibility functions, which may even allow one to constrain the dust location. In particular, observations in the mid-infrared could help to determine whether the dust piles up at the sublimation radius or is located at radii up to 1 au. In addition, we explore observations of the hot exozodiacal dust with the upcoming mid-infrared interferometer Multi AperTure mid-Infrared SpectroScopic Experiment (MATISSE) at the Very Large Telescope Interferometer.

  11. A thermo-electro-mechanical simulation model for hot wire cutting of EPS foam

    DEFF Research Database (Denmark)

    Petkov, Kiril; Hattel, Jesper Henri

    2016-01-01

    A one-dimensional thermo-electro-mechanical mathematical model describing the effects taking place within a Ni-Cr20% wire used in a hot-wire cutting process for free forming and rapid prototyping of expanded polystyrene (EPS) is investigated and simulated. The model implements and solves three semi...... cutting of EPS in contact with a cutting tool made of an electrically heated metal wire attached to a robot device. The finite difference method is used to solve the coupled equations in the two environments (domains) in which the hot-wire operates, namely air and EPS. The model is calibrated against...... experimentally obtained data. Novel findings are a transient temperature-dependent kerfwidth prediction and a relation between kerfwidth and the cutting angle as measured from the horizontal direction. These are important relations in the aim for higher geometrical accuracy of the hot-wire cutting process. (C...

  12. On unique parameters and unified formal form of hot-wire anemometric sensor model

    International Nuclear Information System (INIS)

    LigePza, P.

    2005-01-01

    This note reviews the extensively adopted equations used as models of hot-wire anemometric sensors. An unified formal form of the mathematical model of a hot-wire anemometric sensor with otherwise defined parameters is proposed. Those parameters, static and dynamic, have simple physical interpretation and can be easily determined. They show directly the range of sensor application. They determine the metrological properties of the given sensor in the actual medium. Hence, the parameters' values might be ascribed to each sensor in the given medium and be quoted in manufacturers' catalogues, supplementing the sensor specifications. Because of their simple physical interpretation, those parameters allow the direct comparison of the fundamental metrological properties of various sensors and selection of the optimal sensor for the given research measurement application. The parameters are also useful in modeling complex hot-wire systems

  13. Mathematical and computational modeling simulation of solar drying Systems

    Science.gov (United States)

    Mathematical modeling of solar drying systems has the primary aim of predicting the required drying time for a given commodity, dryer type, and environment. Both fundamental (Fickian diffusion) and semi-empirical drying models have been applied to the solar drying of a variety of agricultural commo...

  14. Validated TRNSYS Model for Solar Assisted Space Heating System

    International Nuclear Information System (INIS)

    Abdalla, Nedal

    2014-01-01

    The present study involves a validated TRNSYS model for solar assisted space heating system as applied to a residential building in Jordan using new detailed radiation models of the TRNSYS 17.1 and geometric building model Trnsys3d for the Google SketchUp 3D drawing program. The annual heating load for a building (Solar House) which is located at the Royal ScientiFIc Society (RS5) in Jordan is estimated under climatological conditions of Amman. The aim of this Paper is to compare measured thermal performance of the Solar House with that modeled using TRNSYS. The results showed that the annual measured space heating load for the building was 6,188 kWh while the heati.ng load for the modeled building was 6,391 kWh. Moreover, the measured solar fraction for the solar system was 50% while the modeled solar fraction was 55%. A comparison of modeled and measured data resulted in percentage mean absolute errors for solar energy for space heating, auxiliary heating and solar fraction of 13%, 7% and 10%, respectively. The validated model will be useful for long-term performance simulation under different weather and operating conditions.(author)

  15. Electrical equivalent model of intermediate band solar cell using ...

    Indian Academy of Sciences (India)

    presents a structure of IBSC based on ZnTe:O. The proposed model uses irradiance and temperature as ... of solar cells. They are based on different processes and properties such as photon recycling, ... The MATLAB interface was used .... ioral model of an arbitrary solar cell to amend the PSPICE simulation performance.

  16. Mathematical modeling of hot air/electrohydrodynamic (EHD) drying kinetics of mushroom slices

    International Nuclear Information System (INIS)

    Taghian Dinani, Somayeh; Hamdami, Nasser; Shahedi, Mohammad; Havet, Michel

    2014-01-01

    Highlights: • Hot air/EHD drying behavior of thin layer mushroom slices was evaluated. • A new empirical model was proposed for drying kinetics modeling of mushroom slices. • The new model presents excellent predictions for hot air/EHD drying of mushroom. - Abstract: Researches about mathematical modeling of electrohydrodynamic (EHD) drying are rare. In this study, hot air combined with electrohydrodynamic (EHD) drying behavior of thin layer mushroom slices was evaluated in a laboratory scale dryer at voltages of 17, 19, and 21 kV and electrode gaps of 5, 6, and 7 cm. The drying curves were fitted to ten different mathematical models (Newton, Page, Modified Page, Henderson and Pabis, Logarithmic, Two-term exponential, Midilli and Kucuk, Wang and Singh, Weibull and Parabolic models) and a proposed new empirical model to select a suitable drying equation for drying mushroom slices in a hot air combined with EHD dryer. Coefficients of the models were determined by non-linear regression analysis and the models were compared based on their coefficient of determination (R 2 ), sum of square errors (SSE) and root mean square error (RMSE) between experimental and predicted moisture ratios. According to the results, the proposed model that contains only three parameters provided the best fit with the experimental data. It was closely followed by the Midilli and Kucuk model that contains four parameters. Therefore, the proposed model can present comfortable usage and excellent predictions for the moisture content changes of mushroom slices in the hot air combined with EHD drying system

  17. FIRST NEW SOLAR MODELS WITH OPAS OPACITY TABLES

    Energy Technology Data Exchange (ETDEWEB)

    Le Pennec, M.; Turck-Chièze, S.; Salmon, S. [CEA/IRFU/Service d’Astrophysique, CE Saclay, F-91191 Gif sur Yvette (France); Blancard, C.; Cossé, P.; Faussurier, G.; Mondet, G. [CEA, DAM, DIF, F-91297 Arpajon (France)

    2015-11-10

    Stellar seismology appears more and more as a powerful tool for a better determination of the fundamental properties of solar-type stars. However, the particular case of the Sun is still challenging. For about a decade now, the helioseismic sound-speed determination has continued to disagree with the standard solar model (SSM) prediction, questioning the reliability of this model. One of the sources of uncertainty could be in the treatment of the transport of radiation from the solar core to the surface. In this Letter, we use the new OPAS opacity tables, recently available for solar modeling, to address this issue. We discuss first the peculiarities of these tables, then we quantify their impact on the solar sound-speed and density profiles using the reduced OPAS tables taken on the grids of the OPAL ones. We use the two evolution codes, Modules for Experiments in Stellar Astrophysics and Code Liégeois d’Evolution Stellaire, that led to similar conclusions in the solar radiative zone. In comparison to commonly used OPAL opacity tables, the new solar models are computed for the most recent photospheric composition with OPAS tables and present improvements to the location of the base of the convective zone and to the description of the solar radiative zone in comparison to the helioseismic observations, even if the differences in the Rosseland mean opacity do not exceed 6%. We finally carry out a comparison to a solar model computed with the OP opacity tables.

  18. A comparison of two atomic models for the radiative properties of dense hot low Z plasmas

    International Nuclear Information System (INIS)

    Minguez, E.; Sauvan, P.; Gil, J.M.; Rodriguez, R.; Rubiano, J.G.; Florido, R.; Martel, P.; Angelo, P.; Schott, R.; Philippe, F.; Leboucher-Dalimier, E.; Mancini, R.

    2003-01-01

    In this work, two different atomic models (ANALOP based on parametric potentials and IDEFIX based on the dicenter model) are used to calculate the opacities for bound-bound transitions in hot dense, low Z plasmas, and the results are compared to each other. In addition, the ANALOP code has been used to compute free-bound cross sections for hydrogen-like ions

  19. Modeling Emerging Solar Cell Materials and Devices

    Science.gov (United States)

    Thongprong, Non

    Organic photovoltaics (OPVs) and perovskite solar cells are emerging classes of solar cell that are promising for clean energy alternatives to fossil fuels. Understanding fundamental physics of these materials is crucial for improving their energy conversion efficiencies and promoting them to practical applications. Current density-voltage (JV) curves; which are important indicators of OPV efficiency, have direct connections to many fundamental properties of solar cells. They can be described by the Shockley diode equation, resulting in fitting parameters; series and parallel resistance (Rs and Rp), diode saturation current ( J0) and ideality factor (n). However, the Shockley equation was developed specifically for inorganic p-n junction diodes, so it lacks physical meanings when it is applied to OPVs. Hence, the puRposes of this work are to understand the fundamental physics of OPVs and to develop new diode equations in the same form as the Shockley equation that are based on OPV physics. We develop a numerical drift-diffusion simulation model to study bilayer OPVs, which will be called the drift-diffusion for bilayer interface (DD-BI) model. The model solves Poisson, drift-diffusion and current-continuity equations self-consistently for charge densities and potential profiles of a bilayer device with an organic heterojunction interface described by the GWWF model. We also derive new diode equations that have JV curves consistent with the DD-BI model and thus will be called self-consistent diode (SCD) equations. Using the DD-BI and the SCD model allows us to understand working principles of bilayer OPVs and physical definitions of the Shockley parameters. Due to low carrier mobilities in OPVs, space charge accumulation is common especially near the interface and electrodes. Hence, quasi-Fermi levels (i.e. chemical potentials), which depend on charge densities, are modified around the interface, resulting in a splitting of quasi-Fermi levels that works as a driving

  20. EVIDENCE OF THE SOLAR EUV HOT CHANNEL AS A MAGNETIC FLUX ROPE FROM REMOTE-SENSING AND IN SITU OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    SONG, H. Q.; CHEN, Y.; Wang, B. [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, and Institute of Space Sciences, Shandong University, Weihai, Shandong 264209 (China); ZHANG, J. [School of Physics, Astronomy and Computational Sciences, George Mason University, Fairfax, VA 22030 (United States); CHENG, X. [School of Astronomy and Space Science, Nanjing University, Nanjing, Jiangsu 210093 (China); HU, Q.; LI, G. [Department of Space Science and CSPAR, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); WANG, Y. M., E-mail: hqsong@sdu.edu.cn [Key Laboratory of Geospace Environment, University of Science and Technology of China, Chinese Academy of Sciences (CAS), Hefei, Anhui 230026 (China)

    2015-07-20

    Hot channels (HCs), high-temperature erupting structures in the lower corona of the Sun, have been proposed as a proxy of magnetic flux ropes (MFRs) since their initial discovery. However, it is difficult to provide definitive proof given the fact that there is no direct measurement of the magnetic field in the corona. An alternative method is to use the magnetic field measurement in the solar wind from in situ instruments. On 2012 July 12, an HC was observed prior to and during a coronal mass ejection (CME) by the Atmospheric Imaging Assembly high-temperature images. The HC is invisible in the EUVI low-temperature images, which only show the cooler leading front (LF). However, both the LF and an ejecta can be observed in the coronagraphic images. These are consistent with the high temperature and high density of the HC and support that the ejecta is the erupted HC. Meanwhile, the associated CME shock was identified ahead of the ejecta and the sheath through the COR2 images, and the corresponding ICME was detected by the Advanced Composition Explorer, showing the shock, sheath, and magnetic cloud (MC) sequentially, which agrees with the coronagraphic observations. Further, the MC average Fe charge state is elevated, containing a relatively low-ionization-state center and a high-ionization-state shell, consistent with the preexisting HC observation and its growth through magnetic reconnection. All of these observations support that the MC detected near the Earth is the counterpart of the erupted HC in the corona for this event. The study provides strong observational evidence of the HC as an MFR.

  1. Evidence of the Solar EUV Hot Channel as a Magnetic Flux Rope from Remote-sensing and in situ Observations

    Science.gov (United States)

    Song, H.

    2015-12-01

    Hot channels (HCs), high-temperature erupting structures in the lower corona of the Sun, have been proposed as a proxy of magnetic flux ropes (MFRs) since their initial discovery. However, it is difficult to provide definitive proof given the fact that there is no direct measurement of the magnetic field in the corona. An alternative method is to use the magnetic field measurement in the solar wind from in situ instruments. On 2012 July 12, an HC was observed prior to and during a coronal mass ejection (CME) by the Atmospheric Imaging Assembly high-temperature images. The HC is invisible in the EUVI low-temperature images, which only show the cooler leading front (LF). However, both the LF and an ejecta can be observed in the coronagraphic images. These are consistent with the high temperature and high density of the HC and support that the ejecta is the erupted HC. Meanwhile, the associated CME shock was identified ahead of the ejecta and the sheath through the COR2 images, and the corresponding ICME was detected by the Advanced Composition Explorer, showing the shock, sheath, and magnetic cloud (MC) sequentially, which agrees with the coronagraphic observations. Further, the MC average Fe charge state is elevated, containing a relatively low-ionization-state center and a high-ionization-state shell, consistent with the preexisting HC observation and its growth through magnetic reconnection. All of these observations support that the MC detected near the Earth is the counterpart of the erupted HC in the corona for this event. The study provides strong observational evidence of the HC as an MFR.

  2. The influence of the solar radiation model on the calcutated solar radiation from a horizontal surface to a tilted surface

    DEFF Research Database (Denmark)

    Andersen, Elsa; Lund, Hans; Furbo, Simon

    2004-01-01

    Measured solar radiation data are most commonly available as total solar radiation on a horizontal surface. When using solar radiation measured on horizontal to calculate the solar radiation on tilted surfaces and thereby the thermal performance of different applications such as buildings and solar...... heating systems, different solar radiation models can be used. The calculation of beam radiation from a horizontal surface to a tilted surface can be done exactly whereas different solar radiation models can calculate the sky diffuse radiation. The sky diffuse radiation can either be assumed evenly...... in the calculation. The weather data are measured at the solar radiation measurement station, SMS at the Department of Civil Engineering at the Technical University of Denmark. In this study the weather data are combined with solar collector calculations based on solar collector test carried out at Solar Energy...

  3. Modeling Skin Injury from Hot Spills on Clothing

    Directory of Open Access Journals (Sweden)

    Torgrim Log

    2017-11-01

    Full Text Available The present work analyzes scald burns from hot beverages, such as coffee and tea, spilled on the lap, i.e., an incident that may occur in daily life. The Pennes bioheat equation is solved numerically for small spills wetting the clothing, i.e., the fabric prevents the spilled liquid from draining away. Temperatures are analyzed in the wetted fabric and the skin layers and the resulting skin injury is calculated based on the basal layer temperature. Parameters influencing burn severity, such as clothing thickness, liquid temperature, removal of fabric and thermal effects of post scald water cooling are analyzed. The fabric cools the water some but represents a threat since the entrapped water results in a prolonged heat supply. The liquid temperature turned out to be the most important injury parameter, where liquid temperature of about 80–85 °C seems to be a limit for developing superficial partial-thickness burns in the present minimum case, i.e., where the liquid just wets the fabric. Spilling water in excess of just wetting the fabric, more severe burns will develop at lower liquid temperatures due to the prolonged heat supply. Higher liquid temperatures will nearly instantly develop more severe burns. It is demonstrated that removal of the clothing within the first seconds after the spill may significantly reduce the scalding severity. The general advice is therefore to avoid excessive heating of beverages and, if the beverage is spilled, to quickly remove the wetted clothing. Prolonged tempered water cooling is advised to improve the healing processes.

  4. New Temperature-based Models for Predicting Global Solar Radiation

    International Nuclear Information System (INIS)

    Hassan, Gasser E.; Youssef, M. Elsayed; Mohamed, Zahraa E.; Ali, Mohamed A.; Hanafy, Ahmed A.

    2016-01-01

    Highlights: • New temperature-based models for estimating solar radiation are investigated. • The models are validated against 20-years measured data of global solar radiation. • The new temperature-based model shows the best performance for coastal sites. • The new temperature-based model is more accurate than the sunshine-based models. • The new model is highly applicable with weather temperature forecast techniques. - Abstract: This study presents new ambient-temperature-based models for estimating global solar radiation as alternatives to the widely used sunshine-based models owing to the unavailability of sunshine data at all locations around the world. Seventeen new temperature-based models are established, validated and compared with other three models proposed in the literature (the Annandale, Allen and Goodin models) to estimate the monthly average daily global solar radiation on a horizontal surface. These models are developed using a 20-year measured dataset of global solar radiation for the case study location (Lat. 30°51′N and long. 29°34′E), and then, the general formulae of the newly suggested models are examined for ten different locations around Egypt. Moreover, the local formulae for the models are established and validated for two coastal locations where the general formulae give inaccurate predictions. Mostly common statistical errors are utilized to evaluate the performance of these models and identify the most accurate model. The obtained results show that the local formula for the most accurate new model provides good predictions for global solar radiation at different locations, especially at coastal sites. Moreover, the local and general formulas of the most accurate temperature-based model also perform better than the two most accurate sunshine-based models from the literature. The quick and accurate estimations of the global solar radiation using this approach can be employed in the design and evaluation of performance for

  5. 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)

  6. Alive and well: A short review about standard solar models

    Energy Technology Data Exchange (ETDEWEB)

    Serenelli, Aldo [Campus UAB, Carrer de Can Magrans S/N, Instituto de Ciencias del Espacio (ICE/CSIC-IEEC), Cerdanyola del Valles (Spain)

    2016-04-15

    Standard solar models (SSMs) provide a reference framework across a number of research fields: solar and stellar models, solar neutrinos, particle physics the most conspicuous among them. The accuracy of the physical description of the global properties of the Sun that SSMs provide has been challenged in the last decade by a number of developments in stellar spectroscopic techniques. Over the same period of time, solar neutrino experiments, and Borexino in particular, have measured the four solar neutrino fluxes from the pp-chains that are associated with 99% of the nuclear energy generated in the Sun. Borexino has also set the most stringent limit on CNO energy generation, only ∝ 40% larger than predicted by SSMs. More recently, and for the first time, radiative opacity experiments have been performed at conditions that closely resemble those at the base of the solar convective envelope. In this article, we review these developments and discuss the current status of SSMs, including its intrinsic limitations. (orig.)

  7. Predictive Models for Photovoltaic Electricity Production in Hot Weather Conditions

    Directory of Open Access Journals (Sweden)

    Jabar H. Yousif

    2017-07-01

    Full Text Available The process of finding a correct forecast equation for photovoltaic electricity production from renewable sources is an important matter, since knowing the factors affecting the increase in the proportion of renewable energy production and reducing the cost of the product has economic and scientific benefits. This paper proposes a mathematical model for forecasting energy production in photovoltaic (PV panels based on a self-organizing feature map (SOFM model. The proposed model is compared with other models, including the multi-layer perceptron (MLP and support vector machine (SVM models. Moreover, a mathematical model based on a polynomial function for fitting the desired output is proposed. Different practical measurement methods are used to validate the findings of the proposed neural and mathematical models such as mean square error (MSE, mean absolute error (MAE, correlation (R, and coefficient of determination (R2. The proposed SOFM model achieved a final MSE of 0.0007 in the training phase and 0.0005 in the cross-validation phase. In contrast, the SVM model resulted in a small MSE value equal to 0.0058, while the MLP model achieved a final MSE of 0.026 with a correlation coefficient of 0.9989, which indicates a strong relationship between input and output variables. The proposed SOFM model closely fits the desired results based on the R2 value, which is equal to 0.9555. Finally, the comparison results of MAE for the three models show that the SOFM model achieved a best result of 0.36156, whereas the SVM and MLP models yielded 4.53761 and 3.63927, respectively. A small MAE value indicates that the output of the SOFM model closely fits the actual results and predicts the desired output.

  8. A dynamic model of an innovative high-temperature solar heating and cooling system

    Directory of Open Access Journals (Sweden)

    Buonomano Annamaria

    2016-01-01

    Full Text Available In this paper a new simulation model of a novel solar heating and cooling system based on innovative high temperature flat plate evacuated solar thermal collector is presented. The system configuration includes: flat-plate evacuated solar collectors, a double-stage LiBr-H2O absorption chiller, gas-fired auxiliary heater, a closed loop cooling tower, pumps, heat exchangers, storage tanks, valves, mixers and controllers. The novelty of this study lies in the utilization of flat-plate stationary solar collectors, manufactured by TVP Solar, rather than concentrating ones (typically adopted for driving double-stage absorption chillers. Such devices show ultra-high thermal efficiencies, even at very high (about 200°C operating temperatures, thanks to the high vacuum insulation. Aim of the paper is to analyse the energy and economic feasibility of such novel technology, by including it in a prototypal solar heating and cooling system. For this purpose, the solar heating and cooling system design and performance were analysed by means of a purposely developed dynamic simulation model, implemented in TRNSYS. A suitable case study is also presented. Here, the simulated plant is conceived for the space heating and cooling and the domestic hot water production of a small building, whose energy needs are fulfilled through a real installation (settled also for experimental purposes built up close to Naples (South Italy. Simulation results show that the investigated system is able to reach high thermal efficiencies and very good energy performance. Finally, the economic analysis shows results comparable to those achieved through similar renewable energy systems.

  9. Development of Solar Drying Model for Selected Cambodian Fish Species

    Science.gov (United States)

    Hubackova, Anna; Kucerova, Iva; Chrun, Rithy; Chaloupkova, Petra; Banout, Jan

    2014-01-01

    A solar drying was investigated as one of perspective techniques for fish processing in Cambodia. The solar drying was compared to conventional drying in electric oven. Five typical Cambodian fish species were selected for this study. Mean solar drying temperature and drying air relative humidity were 55.6°C and 19.9%, respectively. The overall solar dryer efficiency was 12.37%, which is typical for natural convection solar dryers. An average evaporative capacity of solar dryer was 0.049 kg·h−1. Based on coefficient of determination (R 2), chi-square (χ 2) test, and root-mean-square error (RMSE), the most suitable models describing natural convection solar drying kinetics were Logarithmic model, Diffusion approximate model, and Two-term model for climbing perch and Nile tilapia, swamp eel and walking catfish and Channa fish, respectively. In case of electric oven drying, the Modified Page 1 model shows the best results for all investigated fish species except Channa fish where the two-term model is the best one. Sensory evaluation shows that most preferable fish is climbing perch, followed by Nile tilapia and walking catfish. This study brings new knowledge about drying kinetics of fresh water fish species in Cambodia and confirms the solar drying as acceptable technology for fish processing. PMID:25250381

  10. Development of Solar Drying Model for Selected Cambodian Fish Species

    Directory of Open Access Journals (Sweden)

    Anna Hubackova

    2014-01-01

    Full Text Available A solar drying was investigated as one of perspective techniques for fish processing in Cambodia. The solar drying was compared to conventional drying in electric oven. Five typical Cambodian fish species were selected for this study. Mean solar drying temperature and drying air relative humidity were 55.6°C and 19.9%, respectively. The overall solar dryer efficiency was 12.37%, which is typical for natural convection solar dryers. An average evaporative capacity of solar dryer was 0.049 kg·h−1. Based on coefficient of determination (R2, chi-square (χ2 test, and root-mean-square error (RMSE, the most suitable models describing natural convection solar drying kinetics were Logarithmic model, Diffusion approximate model, and Two-term model for climbing perch and Nile tilapia, swamp eel and walking catfish and Channa fish, respectively. In case of electric oven drying, the Modified Page 1 model shows the best results for all investigated fish species except Channa fish where the two-term model is the best one. Sensory evaluation shows that most preferable fish is climbing perch, followed by Nile tilapia and walking catfish. This study brings new knowledge about drying kinetics of fresh water fish species in Cambodia and confirms the solar drying as acceptable technology for fish processing.

  11. Dynamic modeling of human thermal comfort after the transition from an indoor to an outdoor hot environment.

    Science.gov (United States)

    Katavoutas, George; Flocas, Helena A; Matzarakis, Andreas

    2015-02-01

    Thermal comfort under non-steady-state conditions primarily deals with rapid environmental transients and significant alterations of the meteorological conditions, activity, or clothing pattern within the time scale of some minutes. In such cases, thermal history plays an important role in respect to time, and thus, a dynamic approach is appropriate. The present study aims to investigate the dynamic thermal adaptation process of a human individual, after his transition from a typical indoor climate to an outdoor hot environment. Three scenarios of thermal transients have been considered for a range of hot outdoor environmental conditions, employing the dynamic two-node IMEM model. The differences among them concern the radiation field, the activity level, and the body position. The temporal pattern of body temperatures as well as the range of skin wettedness and of water loss have been investigated and compared among the scenarios and the environmental conditions considered. The structure and the temporal course of human energy fluxes as well as the identification of the contribution of body temperatures to energy fluxes have also been studied and compared. In general, the simulation results indicate that the response of a person, coming from the same neutral indoor climate, varies depending on the scenario followed by the individual while being outdoors. The combination of radiation field (shade or not) with the kind of activity (sitting or walking) and the outdoor conditions differentiates significantly the thermal state of the human body. Therefore, 75% of the skin wettedness values do not exceed the thermal comfort limit at rest for a sitting individual under the shade. This percentage decreases dramatically, less than 25%, under direct solar radiation and exceeds 75% for a walking person under direct solar radiation.

  12. Bilinear reduced order approximate model of parabolic distributed solar collectors

    KAUST Repository

    Elmetennani, Shahrazed; Laleg-Kirati, Taous-Meriem

    2015-01-01

    This paper proposes a novel, low dimensional and accurate approximate model for the distributed parabolic solar collector, by means of a modified gaussian interpolation along the spatial domain. The proposed reduced model, taking the form of a low

  13. Numerical modelling of CIGS/CdS solar cell

    Science.gov (United States)

    Devi, Nisha; Aziz, Anver; Datta, Shouvik

    2018-05-01

    In this work, we design and analyze the Cu(In,Ga)Se2 (CIGS) solar cell using simulation software "Solar Cell Capacitance Simulator in One Dimension (SCAPS-1D)". The conventional CIGS solar cell uses various layers, like intrinsic ZnO/Aluminium doped ZnO as transparent oxide, antireflection layer MgF2, and electron back reflection (EBR) layer at CIGS/Mo interface for good power conversion efficiency. We replace this conventional model by a simple model which is easy to fabricate and also reduces the cost of this cell because of use of lesser materials. The new designed model of CIGS solar cell is ITO/CIGS/OVC/CdS/Metal contact, where OVC is ordered vacancy compound. From this simple structure, even at very low illumination we are getting good results. We simulate this CIGS solar cell model by varying various physical parameters of CIGS like thickness, carrier density, band gap and temperature.

  14. Analysis and validation of a quasi-dynamic model for a solar collector field with flat plate collectors and parabolic trough collectors in series for district heating

    DEFF Research Database (Denmark)

    Tian, Zhiyong; Perers, Bengt; Furbo, Simon

    2018-01-01

    performance of the hybrid solar district heating plants is also presented. The measured and simulated results show that the integration of parabolic trough collectors in solar district heating plants can guarantee that the system produces hot water with relatively constant outlet temperature. The daily energy......A quasi-dynamic TRNSYS simulation model for a solar collector field with flat plate collectors and parabolic trough collectors in series was described and validated. A simplified method was implemented in TRNSYS in order to carry out long-term energy production analyses of the whole solar heating...... plant. The advantages of the model include faster computation with fewer resources, flexibility of different collector types in solar heating plant configuration and satisfactory accuracy in both dynamic and long-term analyses. In situ measurements were taken from a pilot solar heating plant with 5960 m...

  15. Modelling solar cells with thermal phenomena taken into account

    International Nuclear Information System (INIS)

    Górecki, K; Górecki, P; Paduch, K

    2014-01-01

    The paper is devoted to modelling properties of solar cells. The authors' electrothermal model of such cells is described. This model takes into account the influence of temperature on its characteristics. Some results of calculations and measurements of selected solar cells are presented and discussed. The good agreement between the results of calculations and measurements was obtained, which proves the correctness of the elaborated model.

  16. Surface-Plasmon-Driven Hot Electron Photochemistry.

    Science.gov (United States)

    Zhang, Yuchao; He, Shuai; Guo, Wenxiao; Hu, Yue; Huang, Jiawei; Mulcahy, Justin R; Wei, Wei David

    2017-11-30

    Visible-light-driven photochemistry has continued to attract heightened interest due to its capacity to efficiently harvest solar energy and its potential to solve the global energy crisis. Plasmonic nanostructures boast broadly tunable optical properties coupled with catalytically active surfaces that offer a unique opportunity for solar photochemistry. Resonant optical excitation of surface plasmons produces energetic hot electrons that can be collected to facilitate chemical reactions. This review sums up recent theoretical and experimental approaches for understanding the underlying photophysical processes in hot electron generation and discusses various electron-transfer models on both plasmonic metal nanostructures and plasmonic metal/semiconductor heterostructures. Following that are highlights of recent examples of plasmon-driven hot electron photochemical reactions within the context of both cases. The review concludes with a discussion about the remaining challenges in the field and future opportunities for addressing the low reaction efficiencies in hot-electron-induced photochemistry.

  17. Hot News Recommendation System from Heterogeneous Websites Based on Bayesian Model

    Directory of Open Access Journals (Sweden)

    Zhengyou Xia

    2014-01-01

    Full Text Available The most current news recommendations are suitable for news which comes from a single news website, not for news from different heterogeneous news websites. Previous researches about news recommender systems based on different strategies have been proposed to provide news personalization services for online news readers. However, little research work has been reported on utilizing hundreds of heterogeneous news websites to provide top hot news services for group customers (e.g., government staffs. In this paper, we propose a hot news recommendation model based on Bayesian model, which is from hundreds of different news websites. In the model, we determine whether the news is hot news by calculating the joint probability of the news. We evaluate and compare our proposed recommendation model with the results of human experts on the real data sets. Experimental results demonstrate the reliability and effectiveness of our method. We also implement this model in hot news recommendation system of Hangzhou city government in year 2013, which achieves very good results.

  18. Hot news recommendation system from heterogeneous websites based on bayesian model.

    Science.gov (United States)

    Xia, Zhengyou; Xu, Shengwu; Liu, Ningzhong; Zhao, Zhengkang

    2014-01-01

    The most current news recommendations are suitable for news which comes from a single news website, not for news from different heterogeneous news websites. Previous researches about news recommender systems based on different strategies have been proposed to provide news personalization services for online news readers. However, little research work has been reported on utilizing hundreds of heterogeneous news websites to provide top hot news services for group customers (e.g., government staffs). In this paper, we propose a hot news recommendation model based on Bayesian model, which is from hundreds of different news websites. In the model, we determine whether the news is hot news by calculating the joint probability of the news. We evaluate and compare our proposed recommendation model with the results of human experts on the real data sets. Experimental results demonstrate the reliability and effectiveness of our method. We also implement this model in hot news recommendation system of Hangzhou city government in year 2013, which achieves very good results.

  19. Extension of thickened and hot lithospheres: Inferences from laboratory modeling

    NARCIS (Netherlands)

    Tirel, C.; Brun, J.P.; Sokoutis, D.

    2006-01-01

    The extension of a previously thickened lithosphere is studied through a series of analogue experiments. The models deformed in free and boundary-controlled gravity spreading conditions that simulate the development of wide rift-type and core complex-type structures. In models, the development of

  20. The virtual enhancements - solar proton event radiation (VESPER) model

    Science.gov (United States)

    Aminalragia-Giamini, Sigiava; Sandberg, Ingmar; Papadimitriou, Constantinos; Daglis, Ioannis A.; Jiggens, Piers

    2018-02-01

    A new probabilistic model introducing a novel paradigm for the modelling of the solar proton environment at 1 AU is presented. The virtual enhancements - solar proton event radiation model (VESPER) uses the European space agency's solar energetic particle environment modelling (SEPEM) Reference Dataset and produces virtual time-series of proton differential fluxes. In this regard it fundamentally diverges from the approach of existing SPE models that are based on probabilistic descriptions of SPE macroscopic characteristics such as peak flux and cumulative fluence. It is shown that VESPER reproduces well the dataset characteristics it uses, and further comparisons with existing models are made with respect to their results. The production of time-series as the main output of the model opens a straightforward way for the calculation of solar proton radiation effects in terms of time-series and the pairing with effects caused by trapped radiation and galactic cosmic rays.

  1. Improvement of sweating model in 2-Node Model and its application to thermal safety for hot environments

    Energy Technology Data Exchange (ETDEWEB)

    Ooka, Ryozo [Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba Meguro-ku, Tokyo 153 8505 (Japan); Minami, Yuriko [Tokyo Electric Power Company, Tokyo (Japan); Sakoi, Tomonori [International Young Researchers Empowerment Center, Shinshu University, Nagano (Japan); Tsuzuki, Kazuyo [National Institute of Advanced Industrial Science and Technology, Tsukuba (Japan); Rijal, H.B. [Integrated Research System for Sustainability Science, The University of Tokyo, Tokyo (Japan)

    2010-07-15

    Recently, due to global warming and the heat-island effect, more and more people are exposed to the dangers of heat disorders. A hot thermal environment can be evaluated using various indices, such as new Standard Effective Temperature (SET{sup *}) using the 2-Node Model (2 NM), Wet Bulb Globe Temperature (WBGT), Predicted Heat Strain (PHS) model, and so on. The authors aim to develop a safety evaluation approach for hot environments. Subject experiments are performed in a laboratory to comprehend the physiological response of the human body. The results are compared with the computed values from the 2 NM and PHS models, and improved the sweating model in 2 NM in order to take into account the relationship with metabolic rate. A demonstration is provided of using the new sweating model for evaluating thermal safety in a hot environment. (author)

  2. Modeling solar radiation at the Earth's surface recent advances

    CERN Document Server

    Badescu, Viorel

    2008-01-01

    Solar radiation data is important for a wide range of applications, e.g. in engineering, agriculture, health sector, and in many fields of the natural sciences. A few examples showing the diversity of applications may include: architecture and building design e.g. air conditioning and cooling systems; solar heating system design and use; solar power generation; weather and climate prediction models; evaporation and irrigation; calculation of water requirements for crops; monitoring plant growth and disease control; skin cancer research. Solar radiation data must be provided in a variety of f

  3. Solar Deployment System (SolarDS) Model: Documentation and Sample Results

    Energy Technology Data Exchange (ETDEWEB)

    Denholm, P.; Drury, E.; Margolis, R.

    2009-09-01

    The Solar Deployment System (SolarDS) model is a bottom-up, market penetration model that simulates the potential adoption of photovoltaics (PV) on residential and commercial rooftops in the continental United States through 2030. NREL developed SolarDS to examine the market competitiveness of PV based on regional solar resources, capital costs, electricity prices, utility rate structures, and federal and local incentives. The model uses the projected financial performance of PV systems to simulate PV adoption for building types and regions then aggregates adoption to state and national levels. The main components of SolarDS include a PV performance simulator, a PV annual revenue calculator, a PV financial performance calculator, a PV market share calculator, and a regional aggregator. The model simulates a variety of installed PV capacity for a range of user-specified input parameters. PV market penetration levels from 15 to 193 GW by 2030 were simulated in preliminary model runs. SolarDS results are primarily driven by three model assumptions: (1) future PV cost reductions, (2) the maximum PV market share assumed for systems with given financial performance, and (3) PV financing parameters and policy-driven assumptions, such as the possible future cost of carbon emissions.

  4. Model for prediction of strip temperature in hot strip steel mill

    International Nuclear Information System (INIS)

    Panjkovic, Vladimir

    2007-01-01

    Proper functioning of set-up models in a hot strip steel mill requires reliable prediction of strip temperature. Temperature prediction is particularly important for accurate calculation of rolling force because of strong dependence of yield stress and strip microstructure on temperature. A comprehensive model was developed to replace an obsolete model in the Western Port hot strip mill of BlueScope Steel. The new model predicts the strip temperature evolution from the roughing mill exit to the finishing mill exit. It takes into account the radiative and convective heat losses, forced flow boiling and film boiling of water at strip surface, deformation heat in the roll gap, frictional sliding heat, heat of scale formation and the heat transfer between strip and work rolls through an oxide layer. The significance of phase transformation was also investigated. Model was tested with plant measurements and benchmarked against other models in the literature, and its performance was very good

  5. Model for prediction of strip temperature in hot strip steel mill

    Energy Technology Data Exchange (ETDEWEB)

    Panjkovic, Vladimir [BlueScope Steel, TEOB, 1 Bayview Road, Hastings Vic. 3915 (Australia)]. E-mail: Vladimir.Panjkovic@BlueScopeSteel.com

    2007-10-15

    Proper functioning of set-up models in a hot strip steel mill requires reliable prediction of strip temperature. Temperature prediction is particularly important for accurate calculation of rolling force because of strong dependence of yield stress and strip microstructure on temperature. A comprehensive model was developed to replace an obsolete model in the Western Port hot strip mill of BlueScope Steel. The new model predicts the strip temperature evolution from the roughing mill exit to the finishing mill exit. It takes into account the radiative and convective heat losses, forced flow boiling and film boiling of water at strip surface, deformation heat in the roll gap, frictional sliding heat, heat of scale formation and the heat transfer between strip and work rolls through an oxide layer. The significance of phase transformation was also investigated. Model was tested with plant measurements and benchmarked against other models in the literature, and its performance was very good.

  6. Solar Luminosity on the Main Sequence, Standard Model and Variations

    Science.gov (United States)

    Ayukov, S. V.; Baturin, V. A.; Gorshkov, A. B.; Oreshina, A. V.

    2017-05-01

    Our Sun became Main Sequence star 4.6 Gyr ago according Standard Solar Model. At that time solar luminosity was 30% lower than current value. This conclusion is based on assumption that Sun is fueled by thermonuclear reactions. If Earth's albedo and emissivity in infrared are unchanged during Earth history, 2.3 Gyr ago oceans had to be frozen. This contradicts to geological data: there was liquid water 3.6-3.8 Gyr ago on Earth. This problem is known as Faint Young Sun Paradox. We analyze luminosity change in standard solar evolution theory. Increase of mean molecular weight in the central part of the Sun due to conversion of hydrogen to helium leads to gradual increase of luminosity with time on the Main Sequence. We also consider several exotic models: fully mixed Sun; drastic change of pp reaction rate; Sun consisting of hydrogen and helium only. Solar neutrino observations however exclude most non-standard solar models.

  7. Experimental and Numerical Analysis of Modelling of Solar Shading

    DEFF Research Database (Denmark)

    Winther, Frederik Vildbrad; Liu, Mingzhe; Heiselberg, Per

    2017-01-01

    The use of solar shading in future low energy office buildings is essential for minimizing energy consumption for building services, while maintaining thermal conditions. Implementing solar shading technologies in energy calculations and thermal building simulation programs is essential in order...... to demonstrate the effect of adaptive solar shading. In order to document the benefits of the shading technology, the description of the shading device in the thermal building simulation software must be described at a reasonably accurate level, related to the specific solar shading device. This research...... presents different approaches for modeling solar shading devices, demonstrating the level of accuracy in relation to measurement conducted in a full-scale façade test facility at Aalborg University. The research bridges the gap between increased complexity of solar shading technologies and the use...

  8. Hot Strange Hadronic Matter in an Effective Model

    Institute of Scientific and Technical Information of China (English)

    QIAN Wei-Liang; SU Ru-Keng; SONG Hong-Qiu

    2003-01-01

    An effective model used to describe the strange hadronic matter with nucleons, Λ-hyperons, and Ξ-hyperonsis extended to finite temperature. The extended model is used to study the density, temperature, and strangeness fractiondependence of the effective masses of baryons in the matter. The thermodynamical quantities, such as free energy andpressure, as well as the equation of state of the matter, are given.

  9. Hot Strange Hadronic Matter in an Effective Model

    Institute of Scientific and Technical Information of China (English)

    QIANWei-Liang; SURu-Keng; SONGHong-Qiu

    2003-01-01

    An effective model used to describe the strange hadronic matter with nucleons, A-hyperons, and [I]-hyperons is extended to finite temperature. The extended model is used to study the density, temperature, and strangeness fraction dependence of the effective masses of baryons in the matter. The thermodynamical quantities, such as free energy and pressure, as well as the equation of state of the matter, are given.

  10. An auto-calibration procedure for empirical solar radiation models

    NARCIS (Netherlands)

    Bojanowski, J.S.; Donatelli, Marcello; Skidmore, A.K.; Vrieling, A.

    2013-01-01

    Solar radiation data are an important input for estimating evapotranspiration and modelling crop growth. Direct measurement of solar radiation is now carried out in most European countries, but the network of measuring stations is too sparse for reliable interpolation of measured values. Instead of

  11. 3-D inelastic analysis methods for hot section components. Volume 2: Advanced special functions models

    Science.gov (United States)

    Wilson, R. B.; Banerjee, P. K.

    1987-01-01

    This Annual Status Report presents the results of work performed during the third year of the 3-D Inelastic Analysis Methods for Hot Sections Components program (NASA Contract NAS3-23697). The objective of the program is to produce a series of computer codes that permit more accurate and efficient three-dimensional analyses of selected hot section components, i.e., combustor liners, turbine blades, and turbine vanes. The computer codes embody a progression of mathematical models and are streamlined to take advantage of geometrical features, loading conditions, and forms of material response that distinguish each group of selected components.

  12. Modeling ethanol spray jet flame in hot-diluted coflow with transported PDF

    NARCIS (Netherlands)

    Ma, L.; Naud, B.; Roekaerts, D.J.E.M.

    2014-01-01

    MILD Combustion, also known as flameless combustion, is attracting wide scientific interest due to its potential of high efficiency and low NOx emission. This paper focuses on the numerical modeling of one of the ethanol spray flame cases from the Delft Spray-in-Hot-Coflow (DSHC) burner, which has

  13. A Unified Physical Model for Creep and Hot Working of Al-Mg Solid Solution Alloys

    Directory of Open Access Journals (Sweden)

    Stefano Spigarelli

    2017-12-01

    Full Text Available The description of the dependence of steady-state creep rate on applied stress and temperature is almost invariably based on the Norton equation or on derived power-law relationships. In hot working, the Norton equation does not work, and is therefore usually replaced with the Garofalo (sinh equation. Both of these equations are phenomenological in nature and can be seldom unambiguously related to microstructural parameters, such as dislocation density, although early efforts in this sense led to the introduction of the “natural power law” with exponent 3. In an attempt to overcome this deficiency, a recent model with sound physical basis has been successfully used to describe the creep response of fcc metals, such as copper. The main advantage of this model is that it does not require any data fitting to predict the strain rate dependence on applied stress and temperature, which is a particularly attractive peculiarity when studying the hot workability of metals. Thus, the model, properly modified to take into account solid solution strengthening effects, has been here applied to the study of the creep and hot-working of simple Al-Mg single phase alloys. The model demonstrated an excellent accuracy in describing both creep and hot working regimes, still maintaining its most important feature, that is, it does not require any fitting of the experimental data.

  14. Transported PDF Modeling of Ethanol Spray in Hot-Diluted Coflow Flame

    NARCIS (Netherlands)

    Ma, L.; Naud, B.; Roekaerts, D.J.E.M.

    2015-01-01

    This paper presents a numerical modeling study of one ethanol spray flame from the Delft Spray-in-Hot-Coflow (DSHC) database, which has been used to study Moderate or Intense Low-oxygen Dilution (MILD) combustion of liquid fuels (Correia Rodrigues et al. Combust. Flame 162(3), 759–773, 2015). A

  15. Model for ion confinement in a hot-electron tandem mirror anchor

    International Nuclear Information System (INIS)

    Baldwin, D.E.

    1980-01-01

    Anisotropic, hot electrons trapped in local minimum-B wells have been proposed as MHD-stabilizing anchors to an otherwise axisymmetric tandem configuration. This work describes a model for plasma confinement between the anchors and the remainder of the system and calcuates the power loss implied by maintenance of this plasma

  16. Comparison between a new TRNSYS model and experimental data of phase change materials in a solar combisystem

    Energy Technology Data Exchange (ETDEWEB)

    Bony, J.; Citherlet, S.

    2007-07-01

    In the framework of the IEA Task 32 (Solar Heating and Cooling Programme), we developed a numeric model to simulate heat transfer in phase change materials (PCM), and experimental data. The analyzed system is bulk PCM plunged in a water tank storage of a solar combisystem (heating and domestic hot water production). The numerical model, based on the enthalpy approach, takes into account hysteresis and subcooling characteristic and also the conduction and the convection in the PCM. This model has been implemented in an existing TRNSYS type of water tank storage. The simulations has been compared with experimental data obtained with a solar installation using water tank storage of about 900 litres, already studied during the IEA Task 26 (Weiss 2003). (author)

  17. Solar radiation modeling and measurements for renewable energy applications: data and model quality

    International Nuclear Information System (INIS)

    Myers, Daryl R.

    2005-01-01

    Measurement and modeling of broadband and spectral terrestrial solar radiation is important for the evaluation and deployment of solar renewable energy systems. We discuss recent developments in the calibration of broadband solar radiometric instrumentation and improving broadband solar radiation measurement accuracy. An improved diffuse sky reference and radiometer calibration and characterization software for outdoor pyranometer calibrations are outlined. Several broadband solar radiation model approaches, including some developed at the National Renewable Energy Laboratory, for estimating direct beam, total hemispherical and diffuse sky radiation are briefly reviewed. The latter include the Bird clear sky model for global, direct beam, and diffuse terrestrial solar radiation; the Direct Insolation Simulation Code (DISC) for estimating direct beam radiation from global measurements; and the METSTAT (Meteorological and Statistical) and Climatological Solar Radiation (CSR) models that estimate solar radiation from meteorological data. We conclude that currently the best model uncertainties are representative of the uncertainty in measured data

  18. Solar radiation modeling and measurements for renewable energy applications: data and model quality

    Energy Technology Data Exchange (ETDEWEB)

    Myers, D.R. [National Renewable Energy Laboratory, Golden, CO (United States)

    2005-07-01

    Measurement and modeling of broadband and spectral terrestrial solar radiation is important for the evaluation and deployment of solar renewable energy systems. We discuss recent developments in the calibration of broadband solar radiometric instrumentation and improving broadband solar radiation measurement accuracy. An improved diffuse sky reference and radiometer calibration and characterization software for outdoor pyranometer calibrations are outlined. Several broadband solar radiation model approaches, including some developed at the National Renewable Energy Laboratory, for estimating direct beam, total hemispherical and diffuse sky radiation are briefly reviewed. The latter include the Bird clear sky model for global, direct beam, and diffuse terrestrial solar radiation; the Direct Insolation Simulation Code (DISC) for estimating direct beam radiation from global measurements; and the METSTAT (Meteorological and Statistical) and Climatological Solar Radiation (CSR) models that estimate solar radiation from meteorological data. We conclude that currently the best model uncertainties are representative of the uncertainty in measured data. (author)

  19. Toward Improved Modeling of Spectral Solar Irradiance for Solar Energy Applications: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Yu [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sengupta, Manajit [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-10-19

    This study introduces the National Renewable Energy Laboratory's (NREL's) recent efforts to extend the capability of the Fast All-sky Radiation Model for Solar applications (FARMS) by computing spectral solar irradiances over both horizontal and inclined surfaces. A new model is developed by computing the optical thickness of the atmosphere using a spectral irradiance model for clear-sky conditions, SMARTS2. A comprehensive lookup table (LUT) of cloud bidirectional transmittance distribution functions (BTDFs) is precomputed for 2002 wavelength bands using an atmospheric radiative transfer model, libRadtran. The solar radiation transmitted through the atmosphere is given by considering all possible paths of photon transmission and the relevent scattering and absorption attenuation. Our results indicate that this new model has an accuracy that is similar to that of state-of-the-art radiative transfer models, but it is significantly more efficient.

  20. Multi-wavelength imaging of solar plasma. High-beta disruption model of solar flares

    International Nuclear Information System (INIS)

    Shibasaki, Kiyoto

    2007-01-01

    Solar atmosphere is filled with plasma and magnetic field. Activities in the atmosphere are due to plasma instabilities in the magnetic field. To understand the physical mechanisms of activities / instabilities, it is necessary to know the physical conditions of magnetized plasma, such as temperature, density, magnetic field, and their spatial structures and temporal developments. Multi-wavelength imaging is essential for this purpose. Imaging observations of the Sun at microwave, X-ray, EUV and optical ranges are routinely going on. Due to free exchange of original data among solar physics and related field communities, we can easily combine images covering wide range of spectrum. Even under such circumstances, we still do not understand the cause of activities in the solar atmosphere well. The current standard model of solar activities is based on magnetic reconnection: release of stored magnetic energy by reconnection is the cause of solar activities on the Sun such as solar flares. However, recent X-ray, EUV and microwave observations with high spatial and temporal resolution show that dense plasma is involved in activities from the beginning. Based on these observations, I propose a high-beta model of solar activities, which is very similar to high-beta disruptions in magnetically confined fusion experiments. (author)

  1. Hot Strange Hadronic Matter in an Effective Model

    Science.gov (United States)

    Qian, Wei-Liang; Su, Ru-Keng; Song, Hong-Qiu

    2003-10-01

    An effective model used to describe the strange hadronic matter with nucleons, Λ-hyperons, and Ξ-hyperons is extended to finite temperature. The extended model is used to study the density, temperature, and strangeness fraction dependence of the effective masses of baryons in the matter. The thermodynamical quantities, such as free energy and pressure, as well as the equation of state of the matter, are given. The project supported in part by National Natural Science Foundation of China under Grant Nos. 10075071, 10047005, 19947001, 19975010, and 10235030, and the CAS Knowledge Innovation Project No. KJCX2-N11. Also supported by the State Key Basic Research Development Program under Grant No. G200077400 and the Exploration Project of Knowledge Innovation Program of the Chinese Academy of Sciences

  2. Radiative redistribution modeling for hot and dense plasmas

    International Nuclear Information System (INIS)

    Mosse, C.; Calisti, A.; Talin, B.; Stamm, R.; Lee, R. W.; Klein, L.

    1999-01-01

    A model based on an extension of the Frequency Fluctuation Model (FFM) is developed to investigate the two-photon processes and particularly the radiative redistribution functions for complex emitters in a wide range of plasmas conditions. The FFM, originally, designed as a fast and reliable numerical procedure for the calculation of the spectral shape of the Stark broadened lines emitted by multi-electron ions, relies on the hypothesis that the emitter-plasma system can be well represented by a set of 'Stark Dressed Transitions', SDT. These transitions connected to each others through a stochastic mixing process accounting for the local microfield random fluctuations, form the basis for the extension of the FFM to computation of non-linear response functions. The formalism of the second order radiative redistribution function is presented and examples are shown

  3. DETAILED MODELLING OF CHARGING BEHAVIOUR OF SMART SOLAR TANKS

    DEFF Research Database (Denmark)

    Fan, Jianhua; Andersen, Elsa; Furbo, Simon

    2010-01-01

    The charging behaviour of smart solar tanks for solar combisystems for one-family houses is investigated with detailed Computational Fluid Dynamics (CFD) modelling and Particle Image Velocimetry (PIV) measurements. The smart solar tank can be charged with a variable auxiliary volume fitted...... or by an electric heating element in a side-arm mounted on the side of the tank. Detailed CFD models of the smart tanks are built with different mesh densities in the tank and in the side-arm. The thermal conditions of the tank during charging are calculated with the CFD models. The fluid flow and temperature...... by the mesh densities, the distribution of computational cells, the physical model and time steps used in the simulations. The findings of the investigations will be used as guidance for creation of CFD models for optimal design of smart solar tanks....

  4. Mathematical modelling of unglazed solar collectors under extreme operating conditions

    DEFF Research Database (Denmark)

    Bunea, M.; Perers, Bengt; Eicher, S.

    2015-01-01

    average temperature levels at the evaporator. Simulation of these systems requires a collector model that can take into account operation at very low temperatures (below freezing) and under various weather conditions, particularly operation without solar irradiation.A solar collector mathematical model......Combined heat pumps and solar collectors got a renewed interest on the heating system market worldwide. Connected to the heat pump evaporator, unglazed solar collectors can considerably increase their efficiency, but they also raise the coefficient of performance of the heat pump with higher...... was found due to the condensation phenomenon and up to 40% due to frost under no solar irradiation. This work also points out the influence of the operating conditions on the collector's characteristics.Based on experiments carried out at a test facility, every heat flux on the absorber was separately...

  5. Occurrence of Legionella in hot water systems of single-family residences in suburbs of two German cities with special reference to solar and district heating.

    Science.gov (United States)

    Mathys, Werner; Stanke, Juliane; Harmuth, Margarita; Junge-Mathys, Elisabeth

    2008-03-01

    A total of 452 samples from hot water systems of randomly selected single family residences in the suburbs of two German cities were analysed for the occurrence of Legionella. Technical data were documented using a standardized questionnaire to evaluate possible factors promoting the growth of the bacterium in these small plumbing systems. All houses were supplied with treated groundwater from public water works. Drinking water quality was within the limits specified in the German regulations for drinking water and the water was not chlorinated. The results showed that plumbing systems in private houses that provided hot water from instantaneous water heaters were free of Legionella compared with a prevalence of 12% in houses with storage tanks and recirculating hot water where maximum counts of Legionella reached 100,000 CFU/100ml. The presence of L. pneumophila accounted for 93.9% of all Legionella positive specimens of which 71.8% belonged to serogroup 1. The volume of the storage tank, interrupting circulation for several hours daily and intermittently raising hot water temperatures to >60 degrees C had no influence on Legionella counts. Plumbing systems with copper pipes were more frequently contaminated than those made of synthetic materials or galvanized steel. An inhibitory effect due to copper was not present. Newly constructed systems (water preparation had a marked influence. More than 50% of all houses using district heating systems were colonized by Legionella. Their significantly lower hot water temperature is thought to be the key factor leading to intensified growth of Legionella. Although hot water systems using solar energy to supplement conventional hot water supplies operate at temperatures 3 degrees C lower than conventional systems, this technique does not seem to promote proliferation of the bacterium. Our data show convincingly that the temperature of the hot water is probably the most important or perhaps the only determinant factor for

  6. Implications of the modelling of stratified hot water storage tanks in the simulation of CHP plants

    Energy Technology Data Exchange (ETDEWEB)

    Campos Celador, A., E-mail: alvaro.campos@ehu.es [ENEDI Research Group-University of the Basque Country, Departamento de Maquinas y Motores Termicos, E.T.S.I. de Bilbao Alameda de Urquijo, s/n 48013 Bilbao, Bizkaia (Spain); Odriozola, M.; Sala, J.M. [ENEDI Research Group-University of the Basque Country, Departamento de Maquinas y Motores Termicos, E.T.S.I. de Bilbao Alameda de Urquijo, s/n 48013 Bilbao, Bizkaia (Spain)

    2011-08-15

    Highlights: {yields} Three different modelling approaches for simulation of hot water tanks are presented. {yields} The three models are simulated within a residential cogeneration plant. {yields} Small differences in the results are found by an energy and exergy analysis. {yields} Big differences between the results are found by an advanced exergy analysis. {yields} Results on the feasibility study are explained by the advanced exergy analysis. - Abstract: This paper considers the effect that different hot water storage tank modelling approaches have on the global simulation of residential CHP plants as well as their impact on their economic feasibility. While a simplified assessment of the heat storage is usually considered in the feasibility studies of CHP plants in buildings, this paper deals with three different levels of modelling of the hot water tank: actual stratified model, ideal stratified model and fully mixed model. These three approaches are presented and comparatively evaluated under the same case of study, a cogeneration plant with thermal storage meeting the loads of an urbanisation located in the Bilbao metropolitan area (Spain). The case of study is simulated by TRNSYS for each one of the three modelling cases and the so obtained annual results are analysed from both a First and Second-Law-based viewpoint. While the global energy and exergy efficiencies of the plant for the three modelling cases agree quite well, important differences are found between the economic results of the feasibility study. These results can be predicted by means of an advanced exergy analysis of the storage tank considering the endogenous and exogenous exergy destruction terms caused by the hot water storage tank.

  7. New phenomenological and differential model for hot working of metallic polycrystalline materials

    International Nuclear Information System (INIS)

    Castellanos, J.; Munoz, J.; Gutierrez, V.; Rieiro, I.; Ruano, O. A.; Carsi, M.

    2012-01-01

    This paper presents a new phenomenological and differential model (that use differential equations) to predict the flow stress of a metallic polycrystalline material under hot working. The model, called MCC, depends on six parameters and uses two internal variables to consider the strain hardening, dynamic recovery and dynamic recrystallization processes that occur under hot working. The experimental validation of the MCC model has been carried out by means of stress-strain curves from torsion tests at high temperature (900 degree centigrade a 1200 degree centigrade) and moderate high strain rate (0.005 s-1 to 5 s-1) in a high nitrogen steel. The results reveal the very good agreement between experimental and predicted stresses. Furthermore, the Garofalo a-parameter and the strain to reach 50 % of recrystallized volume fraction have been employed as a control check being a first step to the physical interpretation of variables and parameters of the MCC model. (Author) 26 refs.

  8. Theoretical modelling of hot gas ingestion through turbine rim seals

    Directory of Open Access Journals (Sweden)

    J. Michael Owen

    2012-12-01

    The nozzle guide vanes create three-dimensional (3D variations in the distribution of pressure in the mainstream annulus and the turbine blades create unsteady effects. Computational fluid dynamics (CFD is both time-consuming and expensive for these 3D unsteady flows, and engine designers tend to use correlations or simple models to predict ingress. This paper describes the application of simple ‘orifice models’, the analytical solutions of which can be used to calculate the sealing effectiveness of turbine rim seals. The solutions agree well with available data for externally-induced ingress, where the effects of rotation are negligible, for rotationally-induced ingress, where the effects of the external flow are small, and for combined ingress, where the effects of both external flow and rotation are significant.

  9. Towards the damage evaluation using Gurson-Tvergaard-Needleman (GTN) model for hot forming processes

    Science.gov (United States)

    Imran, Muhammad; Bambach, Markus

    2018-05-01

    In the production of semi-finished metal products, hot forming is used to eliminate the pores and voids from the casting process under compressive stresses and to modify the microstructure for further processing. In the case of caliber and flat rolling processes, tensile stresses occur at certain roll gap ratios which promote pore formation on nonmetallic inclusion. The formation of new pores contributes to ductile damage and reduces the load carrying capacity of the material. In the literature, the damage nucleation and growth during the hot forming process are not comprehensively described. The aim of this study is to understand the damage initiation and growth mechanism during hot forming processes. Hot tensile tests are performed at different temperatures and strain rates for 16MnCrS5 steel. To investigate the influence of geometrical variations on the damage mechanism, specimens with different stress triaxiality ratios are used. Finite element simulations using the Gurson-Tvergaard-Needleman (GTN) damage model are performed to estimate the critical void fraction for the damage initiation and the evolution of the void volume fraction. The results showed that the GTN model underestimates the softening of the material due to the independence of the temperature and the strain rate.

  10. A dissipative model of solar system

    Science.gov (United States)

    Vladimir, V. G.

    2009-04-01

    In classical model of Solar system of a planet are represented by the material points cooperating under the law of universal gravitation. This model remains fair if planet to consider as absolutely firm spheres with spherical distribution of density. The gravitational potential of such body coincides with potential of a material point, and rotation of each sphere concerning his centre of weights occurs to constant angular speed. Movement concerning the centre of weights of a sphere is represented by rotation with constant angular speed concerning an axis of an any direction, and movement of the centers of weights of spherical planets identically to movement in the appropriate problem of N points. Let's notice, that forms of planets of Solar system are close to spherical as dominant forces at formation of planets are gravitational forces to which forces of molecular interaction in substance of a planet counteract. The model of the isolated Solar system submitted in a not indignant condition N by homogeneous viscoelastic spheres is considered. Under action of own rotation and tidal gravitational forces the spherical planet changes the form: there is "flattening" a planet in a direction of a vector of its angular speed and formation of tidal humps on the lines connecting the centre of a planet with the centers of other planets. From a variational principle of Hamilton the full system of the equations describing movements of the centers of weights of planets, rotations of systems of coordinates, by integrated image connected with planets, and deformations of planets be relative these of systems of coordinates is received. It is supposed, that tidal gravitational, centrifugal and elastic forces result in small change of the spherical form of a planet. In system there are small parameters - inversely proportional of the Young modules of materials of the planets, providing small deformations of planets at influence on them of the centrifugal forces produced by own

  11. Mathematical Modeling of Dual Intake Transparent Transpired Solar Collector

    Directory of Open Access Journals (Sweden)

    Thomas Semenou

    2015-01-01

    Full Text Available Nowadays, in several types of commercial or institutional buildings, a significant rise of transpired solar collectors used to preheat the fresh air of the building can be observed. Nevertheless, when the air mass flow rate is low, the collector efficiency collapses and a large amount of energy remains unused. This paper presents a simple yet effective mathematical model of a transparent transpired solar collector (TTC with dual intake in order to remove stagnation problems in the plenum and ensure a better thermal efficiency and more heat recovery. A thermal model and a pressure loss model were developed. Then, the combined model was validated with experimental data from the Solar Rating and Certification Corporation (SRCC. The results show that the collector efficiency can be up to 70% and even 80% regardless of operating conditions. The temperature gain is able to reach 20°K when the solar irradiation is high.

  12. Model Solar Energy Training Program II. Final Report, July 1, 1981-June 30, 1982.

    Science.gov (United States)

    Talcott Mountain Science Center, Avon, CT.

    Trained personnel will be needed in the future to install solar energy heating and hot water systems, and public school vocational education teachers will be needed to train these technicians. A project to train high school vocational teachers so that they can teach their students about solar energy concepts, manufacturing techniques, testing, and…

  13. A semi-analytical refrigeration cycle modelling approach for a heat pump hot water heater

    Science.gov (United States)

    Panaras, G.; Mathioulakis, E.; Belessiotis, V.

    2018-04-01

    The use of heat pump systems in applications like the production of hot water or space heating makes important the modelling of the processes for the evaluation of the performance of existing systems, as well as for design purposes. The proposed semi-analytical model offers the opportunity to estimate the performance of a heat pump system producing hot water, without using detailed geometrical or any performance data. This is important, as for many commercial systems the type and characteristics of the involved subcomponents can hardly be detected, thus not allowing the implementation of more analytical approaches or the exploitation of the manufacturers' catalogue performance data. The analysis copes with the issues related with the development of the models of the subcomponents involved in the studied system. Issues not discussed thoroughly in the existing literature, as the refrigerant mass inventory in the case an accumulator is present, are examined effectively.

  14. Simulation study on single family house with solar floor and domestic hot water heating system by EESLISM; EESLISM ni yoru taiyonetsu danbo kyuto jutaku no simulation

    Energy Technology Data Exchange (ETDEWEB)

    Roh, H; Udagawa, M [Kogakuin University, Tokyo (Japan)

    1997-11-25

    Indoor thermal conditions and energy performance were simulated, by the aid of EESLISM as a common simulation program for indoor thermal conditions and energy systems, for an actual two-storied single family house equipped with solar-heated floors and a domestic hot water (DHW) heating system, in order to investigate applicability of the simulation program. The house, built in Shibuya Ward in Tokyo, has a total floor area of 164m{sup 2}, with a living room, dining room and study heated by the solar system for a total floor area of 35m{sup 2}. A heat-storage tank is provided, dedicated to the DHW system. The solar collector is of flat type, with selectively light-absorbing planes, having a total collector area of 11.46m{sup 2}. The operating conditions of the floor-heating and DHW systems are almost reproduced. It is necessary to take surrounding conditions into consideration; solar radiation in daytime will be overestimated if adjacent buildings are neglected to give higher temperature in the space and on the wall on the south than the observed level. 6 refs., 5 figs., 1 tab.

  15. Co-Production Performance Evaluation of a Novel Solar Combi System for Simultaneous Pure Water and Hot Water Supply in Urban Households of UAE

    Directory of Open Access Journals (Sweden)

    Nutakki Tirumala Uday Kumar

    2017-04-01

    Full Text Available Water is the most desirable and sparse resource in Gulf cooperation council (GCC region. Utilization of point-of-use (POU water treatment devices has been gaining huge market recently due to increase in knowledge of urban population on health related issues over contaminants in decentralized water distribution networks. However, there is no foolproof way of knowing whether the treated water is free of contaminants harmful for drinking and hence reliance on certified bottled water has increased worldwide. The bottling process right from treatment to delivery is highly unsustainable due to huge energy demand along the supply chain. As a step towards sustainability, we investigated various ways of coupling of membrane distillation (MD process with solar domestic heaters for co-production of domestic heat and pure water. Performance dynamics of various integration techniques have been evaluated and appropriate configuration has been identified for real scale application. A solar combi MD (SCMD system is experimentally tested for single household application for production 20 L/day of pure water and 250 L/day of hot water simultaneously without any auxiliary heating device. The efficiency of co-production system is compared with individual operation of solar heaters and solar membrane distillation.

  16. Possibilities of utilizing solar systems for heating the hot service water in Košice build-up areas KVP and Ťahanovce

    Directory of Open Access Journals (Sweden)

    Peter Horbaj

    2005-12-01

    Full Text Available A production of „HSW“ in block of flats areas by solar collectors means a real alternative to the traditional way of heating by fossil fuels (coal, gas. With this method, it’s possible to save ca. 50 % of energy from the net of the central service of the heat, what can reduce the production of pollutants in the locality, or it can enable to increase the quantity of customers without claims for the restructuralization of the central source. Because Slovakia is the producer of quality solar collectors it’s suitable to use them just for this reason, which could be projected into the price reduction of relatively expensive present systems. On the other side, when using the flat roofs on the block of flats, other useful places are hot occupied and the heating source is nearby the place of it sconsumption. In this case, a collaboration of the solar system and the Central Service of Heat is especially suitable in time with a shortage of the solar radiation.

  17. Theoretical models of Kapton heating in solar array geometries

    Science.gov (United States)

    Morton, Thomas L.

    1992-01-01

    In an effort to understand pyrolysis of Kapton in solar arrays, a computational heat transfer program was developed. This model allows for the different materials and widely divergent length scales of the problem. The present status of the calculation indicates that thin copper traces surrounded by Kapton and carrying large currents can show large temperature increases, but the other configurations seen on solar arrays have adequate heat sinks to prevent substantial heating of the Kapton. Electron currents from the ambient plasma can also contribute to heating of thin traces. Since Kapton is stable at temperatures as high as 600 C, this indicates that it should be suitable for solar array applications. There are indications that the adhesive sued in solar arrays may be a strong contributor to the pyrolysis problem seen in solar array vacuum chamber tests.

  18. Interplanetary Radiation and Internal Charging Environment Models for Solar Sails

    Science.gov (United States)

    Minow, Joseph I.; Altstatt, Richard L.; NeegaardParker, Linda

    2005-01-01

    A Solar Sail Radiation Environment (SSRE) model has been developed for defining charged particle environments over an energy range from 0.01 keV to 1 MeV for hydrogen ions, helium ions, and electrons. The SSRE model provides the free field charged particle environment required for characterizing energy deposition per unit mass, charge deposition, and dose rate dependent conductivity processes required to evaluate radiation dose and internal (bulk) charging processes in the solar sail membrane in interplanetary space. Solar wind and energetic particle measurements from instruments aboard the Ulysses spacecraft in a solar, near-polar orbit provide the particle data over a range of heliospheric latitudes used to derive the environment that can be used for radiation and charging environments for both high inclination 0.5 AU Solar Polar Imager mission and the 1.0 AU L1 solar missions. This paper describes the techniques used to model comprehensive electron, proton, and helium spectra over the range of particle energies of significance to energy and charge deposition in thin (less than 25 micrometers) solar sail materials.

  19. Prediction of Proper Temperatures for the Hot Stamping Process Based on the Kinetics Models

    Science.gov (United States)

    Samadian, P.; Parsa, M. H.; Mirzadeh, H.

    2015-02-01

    Nowadays, the application of kinetics models for predicting microstructures of steels subjected to thermo-mechanical treatments has increased to minimize direct experimentation, which is costly and time consuming. In the current work, the final microstructures of AISI 4140 steel sheets after the hot stamping process were predicted using the Kirkaldy and Li kinetics models combined with new thermodynamically based models in order for the determination of the appropriate process temperatures. In this way, the effect of deformation during hot stamping on the Ae3, Acm, and Ae1 temperatures was considered, and then the equilibrium volume fractions of phases at different temperatures were calculated. Moreover, the ferrite transformation rate equations of the Kirkaldy and Li models were modified by a term proposed by Åkerström to consider the influence of plastic deformation. Results showed that the modified Kirkaldy model is satisfactory for the determination of appropriate austenitization temperatures for the hot stamping process of AISI 4140 steel sheets because of agreeable microstructure predictions in comparison with the experimental observations.

  20. An efficient descriptor model for designing materials for solar cells

    Science.gov (United States)

    Alharbi, Fahhad H.; Rashkeev, Sergey N.; El-Mellouhi, Fedwa; Lüthi, Hans P.; Tabet, Nouar; Kais, Sabre

    2015-11-01

    An efficient descriptor model for fast screening of potential materials for solar cell applications is presented. It works for both excitonic and non-excitonic solar cells materials, and in addition to the energy gap it includes the absorption spectrum (α(E)) of the material. The charge transport properties of the explored materials are modelled using the characteristic diffusion length (Ld) determined for the respective family of compounds. The presented model surpasses the widely used Scharber model developed for bulk heterojunction solar cells. Using published experimental data, we show that the presented model is more accurate in predicting the achievable efficiencies. To model both excitonic and non-excitonic systems, two different sets of parameters are used to account for the different modes of operation. The analysis of the presented descriptor model clearly shows the benefit of including α(E) and Ld in view of improved screening results.

  1. Hawaii Solar Integration Study: Solar Modeling Developments and Study Results; Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Orwig, K.; Corbus, D.; Piwko, R.; Schuerger, M.; Matsuura, M.; Roose, L.

    2012-12-01

    The Hawaii Solar Integration Study (HSIS) is a follow-up to the Oahu Wind Integration and Transmission Study completed in 2010. HSIS focuses on the impacts of higher penetrations of solar energy on the electrical grid and on other generation. HSIS goes beyond the island of Oahu and investigates Maui as well. The study examines reserve strategies, impacts on thermal unit commitment and dispatch, utilization of energy storage, renewable energy curtailment, and other aspects of grid reliability and operation. For the study, high-frequency (2-second) solar power profiles were generated using a new combined Numerical Weather Prediction model/ stochastic-kinematic cloud model approach, which represents the 'sharp-edge' effects of clouds passing over solar facilities. As part of the validation process, the solar data was evaluated using a variety of analysis techniques including wavelets, power spectral densities, ramp distributions, extreme values, and cross correlations. This paper provides an overview of the study objectives, results of the solar profile validation, and study results.

  2. Accurate anisotropic material modelling using only tensile tests for hot and cold forming

    Science.gov (United States)

    Abspoel, M.; Scholting, M. E.; Lansbergen, M.; Neelis, B. M.

    2017-09-01

    Accurate material data for simulations require a lot of effort. Advanced yield loci require many different kinds of tests and a Forming Limit Curve (FLC) needs a large amount of samples. Many people use simple material models to reduce the effort of testing, however some models are either not accurate enough (i.e. Hill’48), or do not describe new types of materials (i.e. Keeler). Advanced yield loci describe the anisotropic materials behaviour accurately, but are not widely adopted because of the specialized tests, and data post-processing is a hurdle for many. To overcome these issues, correlations between the advanced yield locus points (biaxial, plane strain and shear) and mechanical properties have been investigated. This resulted in accurate prediction of the advanced stress points using only Rm, Ag and r-values in three directions from which a Vegter yield locus can be constructed with low effort. FLC’s can be predicted with the equations of Abspoel & Scholting depending on total elongation A80, r-value and thickness. Both predictive methods are initially developed for steel, aluminium and stainless steel (BCC and FCC materials). The validity of the predicted Vegter yield locus is investigated with simulation and measurements on both hot and cold formed parts and compared with Hill’48. An adapted specimen geometry, to ensure a homogeneous temperature distribution in the Gleeble hot tensile test, was used to measure the mechanical properties needed to predict a hot Vegter yield locus. Since for hot material, testing of stress states other than uniaxial is really challenging, the prediction for the yield locus adds a lot of value. For the hot FLC an A80 sample with a homogeneous temperature distribution is needed which is due to size limitations not possible in the Gleeble tensile tester. Heating the sample in an industrial type furnace and tensile testing it in a dedicated device is a good alternative to determine the necessary parameters for the FLC

  3. Investigation of solar photovoltaic module power output by various models

    International Nuclear Information System (INIS)

    Jakhrani, A.Q.; Othman, A.K.; Rigit, A.R.H.; Baini, R.

    2012-01-01

    This paper aims to investigate the power output of a solar photovoltaic module by various models and to formulate a suitable model for predicting the performance of solar photovoltaic modules. The model was used to correct the configurations of solar photovoltaic systems for sustainable power supply. Different types of models namely the efficiency, power, fill factor and current-voltage characteristic curve models have been reviewed. It was found that the examined models predicted a 40% yield of the rated power in cloudy weather conditions and up to 80% in clear skies. The models performed well in terms of electrical efficiency in cloudy days if the influence of low irradiance were incorporated. Both analytical and numerical methods were employed in the formulation of improved model which gave +- 2% error when compared with the rated power output of solar photovoltaic module. The proposed model is more practical in terms of number of variables used and acceptable performance in humid atmospheres. Therefore, it could be useful for the estimation of power output of the solar photovoltaic systems in Sarawak region. (author)

  4. Hot electron transport modelling in fast ignition relevant targets with non-Spitzer resistivity

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, D A; Hoarty, D J; Swatton, D J R [Plasma Physics Department, AWE, Aldermaston, Reading, Berkshire, RG7 4PR (United Kingdom); Hughes, S J, E-mail: david.chapman@awe.co.u [Computational Physics Group, AWE, Aldermaston, Reading, Berkshire, RG7 4PR (United Kingdom)

    2010-08-01

    The simple Lee-More model for electrical resistivity is implemented in the hybrid fast electron transport code THOR. The model is shown to reproduce experimental data across a wide range of temperatures using a small number of parameters. The effect of this model on the heating of simple Al targets by a short-pulse laser is studied and compared to the predictions of the classical Spitzer-Haerm resistivity. The model is then used in simulations of hot electron transport experiments using buried layer targets.

  5. Nanoflare heating model for collisionless solar corona

    Indian Academy of Sciences (India)

    Magnetic reconnection plays a significant role in heating the solar corona. When two oppositely directed magnetic fields come closer to form a current sheet, the current density of the plasma increases due to which magnetic reconnection and conversion of magnetic energy into thermal energy takes place. The present ...

  6. MODELING ACUTE EXPOSURE TO SOLAR RADIATION

    Science.gov (United States)

    One of the major technical challenges in calculating solar flux on the human form has been the complexity of the surface geometry (i.e., the surface normal vis a vis the incident radiation). The American Cancer Society reports that over 80% of skin cancers occur on the face, he...

  7. Numerical simulation model of multijunction solar cell

    NARCIS (Netherlands)

    Babar, M.; Al-Ammar, E.A.; Malik, N.H.

    2012-01-01

    Multi-junction solar cells play an important and significant role in the Concentrated Photovoltaic (CPV) Systems. Recent developments in Concentrated Photovoltaic concerning high power production and cost effective- ness along with better efficiency are due to the advancements in multi-junction

  8. Control and Modelling of Seawater Desalination Using Solar Technology

    Energy Technology Data Exchange (ETDEWEB)

    Roca, L.; Yebra, L. J.; Berenguel, M.; Alarcon, D. C.

    2006-07-01

    Desalination plants play a fundamental role in fighting the shortage of fresh water in places with plentiful seawater resources. This paper briefly describes a solar desalination system designed, erected and operated in the AQUASOL project at the Plataforma Solar de Almeria (PSA), consisting basically of a CPC (Compound Parabolic Concentrator) solar collector field, two water storage tanks, a multi-effect distillation plant (MED) and a Double Effect Absorption Heat Pump (DEAHP). These subsystems have been modeled to estimate system behaviour and develop control techniques for maintaining optimal operating conditions. (Author)

  9. Microstructure Engineering in Hot Strip Mills, Part 1 of 2: Integrated mathematical Model

    Energy Technology Data Exchange (ETDEWEB)

    J.K. Brimacombe; I.V. Samaraseker; E.B. Hawbolt; T.R. Meadowcroft; M. Militzer; W.J. Pool; D.Q. Jin

    1998-09-30

    This report describes the work of developing an integrated model used to predict the thermal history, deformation, roll forces, microstructural evaluation and mechanical properties of steel strip in a hot-strip mill. This achievement results from a join research effort that is part of the American Iron and Steel Institute's (AISI) Advanced Process Control Program, a collaboration between the U.S. DOE and fifteen North American steel makers.

  10. Physical and mathematical modeling of process of frozen ground thawing under hot tank

    Science.gov (United States)

    Zemenkova, M. Y.; Shastunova, U.; Shabarov, A.; Kislitsyn, A.; Shuvaev, A.

    2018-05-01

    A description of a new non-stationary thermophysical model in the “hot tank-frozen ground” system is given, taking into account mass transfer of pore moisture. The results of calculated and experimental data are presented, and the position of the thawing front is shown to be in good agreement with the convective heat transfer due to moisture migration in the thawed ground.

  11. A model for radio emission from solar coronal shocks

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, G. Q.; Chen, L.; Wu, D. J., E-mail: djwu@pmo.ac.cn [Purple Mountain Observatory, CAS, Nanjing 210008 (China)

    2014-05-01

    Solar coronal shocks are very common phenomena in the solar atmosphere and are believed to be the drivers of solar type II radio bursts. However, the microphysical nature of these emissions is still an open question. This paper proposes that electron cyclotron maser (ECM) emission is responsible for the generation of radiation from the coronal shocks. In the present model, an energetic ion beam accelerated by the shock first excites the Alfvén wave (AW), then the excited AW leads to the formation of a density-depleted duct along the foreshock boundary of the shock. In this density-depleted duct, the energetic electron beam produced via the shock acceleration can effectively excite radio emission by ECM instability. Our results show that this model may potentially be applied to solar type II radio bursts.

  12. A model for radio emission from solar coronal shocks

    International Nuclear Information System (INIS)

    Zhao, G. Q.; Chen, L.; Wu, D. J.

    2014-01-01

    Solar coronal shocks are very common phenomena in the solar atmosphere and are believed to be the drivers of solar type II radio bursts. However, the microphysical nature of these emissions is still an open question. This paper proposes that electron cyclotron maser (ECM) emission is responsible for the generation of radiation from the coronal shocks. In the present model, an energetic ion beam accelerated by the shock first excites the Alfvén wave (AW), then the excited AW leads to the formation of a density-depleted duct along the foreshock boundary of the shock. In this density-depleted duct, the energetic electron beam produced via the shock acceleration can effectively excite radio emission by ECM instability. Our results show that this model may potentially be applied to solar type II radio bursts.

  13. Improved Solar-Radiation-Pressure Models for GPS Satellites

    Science.gov (United States)

    Bar-Sever, Yoaz; Kuang, Da

    2006-01-01

    A report describes a series of computational models conceived as an improvement over prior models for determining effects of solar-radiation pressure on orbits of Global Positioning System (GPS) satellites. These models are based on fitting coefficients of Fourier functions of Sun-spacecraft- Earth angles to observed spacecraft orbital motions.

  14. Measurements and modeling of total solar irradiance in X-class solar flares

    International Nuclear Information System (INIS)

    Moore, Christopher Samuel; Chamberlin, Phillip Clyde; Hock, Rachel

    2014-01-01

    The Total Irradiance Monitor (TIM) from NASA's SOlar Radiation and Climate Experiment can detect changes in the total solar irradiance (TSI) to a precision of 2 ppm, allowing observations of variations due to the largest X-class solar flares for the first time. Presented here is a robust algorithm for determining the radiative output in the TIM TSI measurements, in both the impulsive and gradual phases, for the four solar flares presented in Woods et al., as well as an additional flare measured on 2006 December 6. The radiative outputs for both phases of these five flares are then compared to the vacuum ultraviolet (VUV) irradiance output from the Flare Irradiance Spectral Model (FISM) in order to derive an empirical relationship between the FISM VUV model and the TIM TSI data output to estimate the TSI radiative output for eight other X-class flares. This model provides the basis for the bolometric energy estimates for the solar flares analyzed in the Emslie et al. study.

  15. Utilizing hot electrons

    Energy Technology Data Exchange (ETDEWEB)

    Nozik, Arthur J.

    2018-03-01

    In current solar cells, any photon energy exceeding the semiconductor bandgap is lost before being collected, limiting the cell performance. Hot carrier solar cells could avoid these losses. Now, a detailed experimental study and analysis shows that this strategy could lead to an improvement of the photoconversion efficiency in practice.

  16. Self-Consistent Atmosphere Models of the Most Extreme Hot Jupiters

    Science.gov (United States)

    Lothringer, Joshua; Barman, Travis

    2018-01-01

    We present a detailed look at self-consistent PHOENIX atmosphere models of the most highly irradiated hot Jupiters known to exist. These hot Jupiters typically have equilibrium temperatures approaching and sometimes exceeding 3000 K, orbiting A, F, and early-G type stars on orbits less than 0.03 AU (10x closer than Mercury is to the Sun). The most extreme example, KELT-9b, is the hottest known hot Jupiter with a measured dayside temperature of 4600 K. Many of the planets we model have recently attracted attention with high profile discoveries, including temperature inversions in WASP-33b and WASP-121, changing phase curve offsets possibly caused by magnetohydrodymanic effects in HAT-P-7b, and TiO in WASP-19b. Our modeling provides a look at the a priori expectations for these planets and helps us understand these recent discoveries. We show that, in the hottest cases, all molecules are dissociated down to relatively high pressures. These planets may have detectable temperature inversions, more akin to thermospheres than stratospheres in that an optical absorber like TiO or VO is not needed. Instead, the inversions are created by a lack of cooling in the IR combined with heating from atoms and ions at UV and blue optical wavelengths. We also reevaluate some of the assumptions that have been made in retrieval analyses of these planets.

  17. Modeling of hot-mix asphalt compaction : a thermodynamics-based compressible viscoelastic model

    Science.gov (United States)

    2010-12-01

    Compaction is the process of reducing the volume of hot-mix asphalt (HMA) by the application of external forces. As a result of compaction, the volume of air voids decreases, aggregate interlock increases, and interparticle friction increases. The qu...

  18. Improved Statistical Model Of 10.7-cm Solar Radiation

    Science.gov (United States)

    Vedder, John D.; Tabor, Jill L.

    1993-01-01

    Improved mathematical model simulates short-term fluctuations of flux of 10.7-cm-wavelength solar radiation during 91-day averaging period. Called "F10.7 flux", important as measure of solar activity and because it is highly correlated with ultraviolet radiation causing fluctuations in heating and density of upper atmosphere. F10.7 flux easily measureable at surface of Earth.

  19. The problem of multicollinearity in horizontal solar radiation estimation models and a new model for Turkey

    International Nuclear Information System (INIS)

    Demirhan, Haydar

    2014-01-01

    Highlights: • Impacts of multicollinearity on solar radiation estimation models are discussed. • Accuracy of existing empirical models for Turkey is evaluated. • A new non-linear model for the estimation of average daily horizontal global solar radiation is proposed. • Estimation and prediction performance of the proposed and existing models are compared. - Abstract: Due to the considerable decrease in energy resources and increasing energy demand, solar energy is an appealing field of investment and research. There are various modelling strategies and particular models for the estimation of the amount of solar radiation reaching at a particular point over the Earth. In this article, global solar radiation estimation models are taken into account. To emphasize severity of multicollinearity problem in solar radiation estimation models, some of the models developed for Turkey are revisited. It is observed that these models have been identified as accurate under certain multicollinearity structures, and when the multicollinearity is eliminated, the accuracy of these models is controversial. Thus, a reliable model that does not suffer from multicollinearity and gives precise estimates of global solar radiation for the whole region of Turkey is necessary. A new nonlinear model for the estimation of average daily horizontal solar radiation is proposed making use of the genetic programming technique. There is no multicollinearity problem in the new model, and its estimation accuracy is better than the revisited models in terms of numerous statistical performance measures. According to the proposed model, temperature, precipitation, altitude, longitude, and monthly average daily extraterrestrial horizontal solar radiation have significant effect on the average daily global horizontal solar radiation. Relative humidity and soil temperature are not included in the model due to their high correlation with precipitation and temperature, respectively. While altitude has

  20. Modelling of Hot Water Storage Tank for Electric Grid Integration and Demand Response Control

    DEFF Research Database (Denmark)

    Sinha, Rakesh; Bak-Jensen, Birgitte; Pillai, Jayakrishnan Radhakrishna

    2017-01-01

    District heating (DH), based on electric boilers, when integrated into electric network has potential of flexible load with direct/indirect storage to increase the dynamic stability of the grid in terms of power production and consumption with wind and solar. The two different models of electric...

  1. Probability model for worst case solar proton event fluences

    International Nuclear Information System (INIS)

    Xapsos, M.A.; Summers, G.P.; Barth, J.L.; Stassinopoulos, E.G.; Burke, E.A.

    1999-01-01

    The effects that solar proton events have on microelectronics and solar arrays are important considerations for spacecraft in geostationary orbits, polar orbits and on interplanetary missions. A predictive model of worst case solar proton event fluences is presented. It allows the expected worst case event fluence to be calculated for a given confidence level and for periods of time corresponding to space missions. The proton energy range is from >1 to >300 MeV, so that the model is useful for a variety of radiation effects applications. For each proton energy threshold, the maximum entropy principle is used to select the initial distribution of solar proton event fluences. This turns out to be a truncated power law, i.e., a power law for smaller event fluences that smoothly approaches zero at a maximum fluence. The strong agreement of the distribution with satellite data for the last three solar cycles indicates this description captures the essential features of a solar proton event fluence distribution. Extreme value theory is then applied to the initial distribution of events to obtain the model of worst case fluences

  2. SRADLIB: A C Library for Solar Radiation Modelling

    Energy Technology Data Exchange (ETDEWEB)

    Balenzategui, J. L. [Ciemat. Madrid (Spain)

    2000-07-01

    This document shows the result of an exhaustive study about the theoretical and numerical models available in the literature about solar radiation modelling. The purpose of this study is to develop or adapt mathematical models describing the solar radiation specifically for Spain locations as well as to create computer tools able to support the labour of researchers or engineers needing solar radiation data to solve or improve the technical or energetic performance of solar systems. As results of this study and revision, a C library (SRADLIB) is presented as a key for the compilation of the mathematical models from different authors, for the comparison among the different approaches and for its application in computer programs. Different topics related to solar radiation and its modelling are first discussed, including the assumptions and conventions adopted and describing the most accepted and used current state-of-the-art models. some typical problems in the numerical calculation of radiation values are also posed with the proposed solution. The document includes next a complete reference of the developed functions, with many examples of application and calculus. (Author) 24 refs.

  3. SRADLIB: A C Library for Solar Radiation Modelling

    International Nuclear Information System (INIS)

    Balenzategui, J. L.

    1999-01-01

    This document shows the result of an exhaustive study about the theoretical and numerical models available in the literature about solar radiation modelling. The purpose of this study is to develop or adapt mathematical models describing the solar radiation specifically for Spain locations as well as to create computer tools able to support the labour of researchers or engineers needing solar radiation data to solve or improve the technical or energetic performance of solar systems. As result of this study and revision, a C library (SRADLIB) is presented as a key tool for the compilation of the mathematical models from different authors, for the comparison among the different approaches and for its application in computer programs. Different topics related to solar radiation and its modelling are first discussed, including the assumptions and conventions adopted and describing the most accepted and used current state-of-the-art models. Some typical problems in the numerical calculation of radiation values are also posed with the proposed solution. The document includes next a complete reference of the developed functions, with many examples of application and calculus. (Author) 24 refs

  4. Production of solar radiation bankable datasets from high-resolution solar irradiance derived with dynamical downscaling Numerical Weather prediction model

    Directory of Open Access Journals (Sweden)

    Yassine Charabi

    2016-11-01

    Full Text Available A bankable solar radiation database is required for the financial viability of solar energy project. Accurate estimation of solar energy resources in a country is very important for proper siting, sizing and life cycle cost analysis of solar energy systems. During the last decade an important progress has been made to develop multiple solar irradiance database (Global Horizontal Irradiance (GHI and Direct Normal Irradiance (DNI, using satellite of different resolution and sophisticated models. This paper assesses the performance of High-resolution solar irradiance derived with dynamical downscaling Numerical Weather Prediction model with, GIS topographical solar radiation model, satellite data and ground measurements, for the production of bankable solar radiation datasets. For this investigation, NWP model namely Consortium for Small-scale Modeling (COSMO is used for the dynamical downscaling of solar radiation. The obtained results increase confidence in solar radiation data base obtained from dynamical downscaled NWP model. The mean bias of dynamical downscaled NWP model is small, on the order of a few percents for GHI, and it could be ranked as a bankable datasets. Fortunately, these data are usually archived in the meteorological department and gives a good idea of the hourly, monthly, and annual incident energy. Such short time-interval data are valuable in designing and operating the solar energy facility. The advantage of the NWP model is that it can be used for solar radiation forecast since it can estimate the weather condition within the next 72–120 hours. This gives a reasonable estimation of the solar radiation that in turns can be used to forecast the electric power generation by the solar power plant.

  5. Dynamic Modeling of the Solar Field in Parabolic Trough Solar Power Plants

    Directory of Open Access Journals (Sweden)

    Lourdes A. Barcia

    2015-11-01

    Full Text Available Parabolic trough solar power plants use a thermal fluid to transfer thermal energy from solar radiation to a water-steam Rankine cycle in order to drive a turbine that, coupled to an electrical generator, produces electricity. These plants have a heat transfer fluid (HTF system with the necessary elements to transform solar radiation into heat and to transfer that thermal energy to the water-steam exchangers. In order to get the best possible performance in the Rankine cycle and, hence, in the thermal plant, it is necessary that the thermal fluid reach its maximum temperature when leaving the solar field (SF. Also, it is mandatory that the thermal fluid does not exceed the maximum operating temperature of the HTF, above which it degrades. It must be noted that the optimal temperature of the thermal fluid is difficult to obtain, since solar radiation can change abruptly from one moment to another. The aim of this document is to provide a model of an HTF system that can be used to optimize the control of the temperature of the fluid without interfering with the normal operation of the plant. The results obtained with this model will be contrasted with those obtained in a real plant.

  6. Solar heating still in the early stages. Changes for hot water production - VDI meeting 'Efficient heating systems'

    Energy Technology Data Exchange (ETDEWEB)

    Goehringer, P

    1976-10-01

    More and more realism replaces the initial euphoria concerning the discussion on solar heating. Not only the possibilities are considered these days, but also the limits of this still controversial way of heating. This impression was deepened by a meeting of the VDI-Gesellschaft Technische Gebaeudeausruestung (Society for the technical equipment of buildings) held in Bonn. The heating of water with solar energy during the summer is viewed optimistically by the experts - as far as space heating is concerned, the sun collector is conceded only a very modest position in Central Europe within integrated heating systems. It is true that solar technology in the USA is already very sophisticated and economically feasible in many cases; however, techniques cannot be adopted unconditionally for Europe, as the average values of global solar radiation are much lower here. Thus, different technologies will be required.

  7. The impact of silicon solar cell architecture and cell interconnection on energy yield in hot & sunny climates

    KAUST Repository

    Haschke, Jan; Seif, Johannes P.; Riesen, Yannick; Tomasi, Andrea; Cattin, Jean; Tous, Loï c; Choulat, Patrick; Aleman, Monica; Cornagliotti, Emanuele; Uruena, Angel; Russell, Richard; Duerinckx, Filip; Champliaud, Jonathan; Levrat, Jacques; Abdallah, Amir A.; Aï ssa, Brahim; Tabet, Nouar; Wyrsch, Nicolas; Despeisse, Matthieu; Szlufcik, Jozef; De Wolf, Stefaan; Ballif, Christophe

    2017-01-01

    architectures, including so-called Aluminum back-surface-field (BSF), passivated emitter and rear cell (PERC), passivated emitter rear totally diffused (PERT), and silicon heterojunction (SHJ) solar cells. We compare measured temperature coefficients (TC

  8. Deformation Characteristic and Constitutive Modeling of 2707 Hyper Duplex Stainless Steel under Hot Compression

    Directory of Open Access Journals (Sweden)

    Huabing Li

    2016-09-01

    Full Text Available Hot deformation behavior and microstructure evolution of 2707 hyper duplex stainless steel (HDSS were investigated through hot compression tests in the temperature range of 900–1250 °C and strain rate range of 0.01–10 s−1. The results showed that the flow behavior strongly depended on strain rate and temperature, and flow stress increased with increasing strain rate and decreasing temperature. At lower temperatures, many precipitates appeared in ferrite and distributed along the deformation direction, which could restrain processing of discontinuous dynamic recrystallization (DRX because of pinning grain boundaries. When the temperature increased to 1150 °C, the leading softening behaviors were dynamic recovery (DRV in ferrite and discontinuous DRX in austenite. When the temperature reached 1250 °C, softening behavior was mainly DRV in ferrite. The increase of strain rate was conducive to the occurrence of discontinuous DRX in austenite. A constitutive equation at peak strain was established and the results indicated that 2707 HDSS had a higher Q value (569.279 kJ·mol−1 than other traditional duplex stainless steels due to higher content of Cr, Mo, Ni, and N. Constitutive modeling considering strain was developed to model the hot deformation behavior of 2707 HDSS more accurately, and the correlation coefficient and average absolute relative error were 0.992 and 5.22%, respectively.

  9. Single and multijunction silicon based thin film solar cells on a flexible substrate with absorber layers made by hot-wire CVD

    Science.gov (United States)

    Li, Hongbo

    2007-09-01

    With the worldwide growing concern about reliable energy supply and the environmental problems of fossil and nuclear energy production, the need for clean and sustainable energy sources is evident. Solar energy conversion, such as in photovoltaic systems, can play a major role in the urgently needed energy transition in electricity production. Solar cells based on thin film silicon and its alloys are a promising candidate that is capable of fulfilling the fast increasing demand of a reliable solar cell supply. The conventional method to deposit silicon thin films is based on plasma enhanced chemical vapour deposition (PECVD) techniques, which have the disadvantage of increasing film inhomogeneity at a high deposition rate when scaling up for the industrial production. In this thesis, we study the possibility of making high efficiency single and multijunction thin film silicon solar cells with the so-called hot-wire CVD technique, in which no strong electromagnetic field is involved in the deposition. Therefore, the up-scaling for industrial production is straightforward. We report and discuss our findings on the correlation of substrate surface rms roughness and the main output parameter of a solar cell, the open circuit voltage Voc of c-Si:H n i p cells. By considering all the possible reasons that could influence the Voc of such cells, we conclude that the near linear correlation of Voc and substrate surface rms roughness is the result the two most probable reasons: the unintentional doping through the cracks originated near the valleys of the substrate surface due to the in-diffusion of impurities, and the high density electrical defects formed by the collision of columnar silicon structures. Both of them relate to the morphology of substrate surface. Therefore, to have the best cell performance on a rough substrate surface, a good control on the substrate surface morphology is necessary. Another issue influencing the performance of c-Si:H solar cells is the

  10. Cascade Utilization of Energy in Solar Photovoltaic Hot Water System%太阳能光伏热水系统的能量梯级利用

    Institute of Scientific and Technical Information of China (English)

    关欣; 王艳迪; 向勇涛; 郭志波

    2012-01-01

    为了实现太阳能光伏发电系统中用于冷却太阳能电池的低品位热能利用,本文提出了太阳能光伏热水系统。通过对单体光伏光热系统(PV/T)的实验研究表明,在单体PV/T放置角度为30°,流量为200 L/h时,集热效率可达到最大值65.6%,系统的平均发电效率为14.3%,瞬时综合效率最大为83%,达到了能量的梯级利用。%To realize the use of low-grade thermal energy after cooling solar cells in solar photovoltaic systems,this paper puts forward a solar photovoltaic hot water system(PV/T).The experiment of the PV/T system shows,at the condition that inclination is 30°,and flow rate is 200 L/h,the maximum heat-collecting efficiency can be achieved at 65.6%and the average power generation efficiency is 14.3%, the maximum instantaneous overall efficiency is 83%,which realize the cascade utilization of energy.

  11. Reading The Sun: A Three Dimensional Visual Model of The Solar Environment During Solar Cycle 24

    Science.gov (United States)

    Carranza-fulmer, T. L.; Moldwin, M.

    2014-12-01

    The sun is a powerful force that has proven to our society that it has a large impact on our lives. Unfortunately, there is still a lack of awareness on how the sun is capable of affecting Earth. The over all idea of "Reading The Sun" installation is to help demonstrate how the sun impacts the Earth, by compiling various data sources from satellites (SOHO, SDO, and STERO) with solar and solar wind models (MAS and ENLIL) to create a comprehensive three dimensional display of the solar environment. It focuses on the current solar maximum of solar cycle 24 and a CME that impacted Earth's magnetic field on February 27, 2014, which triggered geomagnetic storms around the Earth's poles. The CME was an after-effect of a class X4.9 solar flare, which was released from the sun on February 25, 2014. "Reading The Sun" is a 48" x 48" x 48" hanging model of the sun with color coded open opposing magnetic field lines along with various layers of the solar atmosphere, the heliospheric current sheet, and the inner planets. At the center of the xyz axis is the sun with the open magnetic field lines and the heliospheric current sheet permeating inner planetary space. The xyz axes are color coded to represent various types of information with corresponding visual images for the viewer to be able to read the model. Along the z-axis are three colors (yellow, orange, and green) that represent the different layers of the solar atmosphere (photosphere, chromosphere, and corona) that correspond to three satellite images in various spectrums related to a CME and Solar Flare and the xy-plane shows where the inner planets are in relation to the sun. The exhibit in which "Reading The Sun "is being displayed is called, The Rotation of Language at the Wheather Again Gallery in Rockaway, New York. The intent of the exhibit is to both celebrate as well as present a cautionary tale on the ability of human language to spark and ignite the individual and collective imagination towards an experience

  12. Prediction of hourly solar radiation with multi-model framework

    International Nuclear Information System (INIS)

    Wu, Ji; Chan, Chee Keong

    2013-01-01

    Highlights: • A novel approach to predict solar radiation through the use of clustering paradigms. • Development of prediction models based on the intrinsic pattern observed in each cluster. • Prediction based on proper clustering and selection of model on current time provides better results than other methods. • Experiments were conducted on actual solar radiation data obtained from a weather station in Singapore. - Abstract: In this paper, a novel multi-model prediction framework for prediction of solar radiation is proposed. The framework started with the assumption that there are several patterns embedded in the solar radiation series. To extract the underlying pattern, the solar radiation series is first segmented into smaller subsequences, and the subsequences are further grouped into different clusters. For each cluster, an appropriate prediction model is trained. Hence a procedure for pattern identification is developed to identify the proper pattern that fits the current period. Based on this pattern, the corresponding prediction model is applied to obtain the prediction value. The prediction result of the proposed framework is then compared to other techniques. It is shown that the proposed framework provides superior performance as compared to others

  13. Synoptic, Global Mhd Model For The Solar Corona

    Science.gov (United States)

    Cohen, Ofer; Sokolov, I. V.; Roussev, I. I.; Gombosi, T. I.

    2007-05-01

    The common techniques for mimic the solar corona heating and the solar wind acceleration in global MHD models are as follow. 1) Additional terms in the momentum and energy equations derived from the WKB approximation for the Alfv’en wave turbulence; 2) some empirical heat source in the energy equation; 3) a non-uniform distribution of the polytropic index, γ, used in the energy equation. In our model, we choose the latter approach. However, in order to get a more realistic distribution of γ, we use the empirical Wang-Sheeley-Arge (WSA) model to constrain the MHD solution. The WSA model provides the distribution of the asymptotic solar wind speed from the potential field approximation; therefore it also provides the distribution of the kinetic energy. Assuming that far from the Sun the total energy is dominated by the energy of the bulk motion and assuming the conservation of the Bernoulli integral, we can trace the total energy along a magnetic field line to the solar surface. On the surface the gravity is known and the kinetic energy is negligible. Therefore, we can get the surface distribution of γ as a function of the final speed originating from this point. By interpolation γ to spherically uniform value on the source surface, we use this spatial distribution of γ in the energy equation to obtain a self-consistent, steady state MHD solution for the solar corona. We present the model result for different Carrington Rotations.

  14. Multicriteria GIS modeling of wind and solar farms in Colorado

    Energy Technology Data Exchange (ETDEWEB)

    Janke, Jason R. [Metropolitan State College of Denver, Department of Earth and Atmospheric Sciences, CB 22 P.O. Box 173362-22, Denver, CO 80217-3362 (United States)

    2010-10-15

    The majority of electricity and heat in Colorado comes from coal and natural gas; however, renewable energy sources will play an integral role in the state's energy future. Colorado is the 11th windiest state and has more than 250 sunny days per year. The objectives of this research are to: 1) determine which landcover classes are affiliated with high wind and solar potential; and 2) identify areas that are suitable for wind and solar farms using multicriteria GIS modelling techniques. Renewable potential (NREL wind speed measurements at 50 m above the ground and NREL annual insolation data), landcover, population density, federal lands, and distance to roads, transmission lines, and cities were reclassified according to their suitability. Each was assigned weights based on their relative importance to one another. Superb wind classes are located in high alpine areas. Unfortunately, these areas are not suitable for large-scale wind farm development due to their inaccessibility and location within a sensitive ecosystem. Federal lands have low wind potential. According to the GIS model, ideal areas for wind farm development are located in northeastern Colorado. About 41 850 km{sup 2} of the state has model scores that are in the 90-100% range. Although annual solar radiation varies slightly, inter-mountain areas receive the most insolation. As far as federal lands, Indian reservations have the greatest solar input. The GIS model indicates that ideal areas for solar development are located in northwestern Colorado and east of Denver. Only 191 km{sup 2} of the state had model scores that were in the 90-100% range. These results suggest that the variables used in this analysis have more of an effect at eliminating non-suitable areas for large-scale solar farms; a greater area exists for suitable wind farms. However, given the statewide high insolation values with minimal variance, solar projects may be better suited for small-scale residential or commercial

  15. On the accuracy of current TCAD hot carrier injection models in nanoscale devices

    Science.gov (United States)

    Zaka, Alban; Rafhay, Quentin; Iellina, Matteo; Palestri, Pierpaolo; Clerc, Raphaël; Rideau, Denis; Garetto, Davide; Dornel, Erwan; Singer, Julien; Pananakakis, Georges; Tavernier, Clément; Jaouen, Hervé

    2010-12-01

    In this work, the hot electron injection models presently available for technology support have been investigated within the context of the development of advanced embedded non-volatile memories. The distribution functions obtained by these models (namely the Fiegna Model - FM [1], the Lucky Electron Model - LEM [2] and the recently implemented Spherical Harmonics Expansion of the Boltzman's Transport Equation - SHE [3]), have been systematically compared to rigorous Monte Carlo (MC) results [4], both in homogeneous and device conditions. Gate-to-drain current ratio and gate current density simulation has also been benchmarked in device simulations. Results indicate that local models such as FM, can partially capture the channel hot electron injection, at the price of model parameter adjustments. Moreover, at least in the device and field condition considered in this work, an overall better agreement with MC simulations has been obtained using the 1st order SHE, even without any particular fitting procedure. Extending the results presented in [3] by exploring shorter gate lengths and addressing the floating gate voltage dependence of the gate current, this work shows that the SHE method could contribute to bridge the gap between the rigorous but time consuming MC method and less rigorous but suitable TCAD local models.

  16. Modelling of diffuse solar fraction with multiple predictors

    Energy Technology Data Exchange (ETDEWEB)

    Ridley, Barbara; Boland, John [Centre for Industrial and Applied Mathematics, University of South Australia, Mawson Lakes Boulevard, Mawson Lakes, SA 5095 (Australia); Lauret, Philippe [Laboratoire de Physique du Batiment et des Systemes, University of La Reunion, Reunion (France)

    2010-02-15

    For some locations both global and diffuse solar radiation are measured. However, for many locations, only global radiation is measured, or inferred from satellite data. For modelling solar energy applications, the amount of radiation on a tilted surface is needed. Since only the direct component on a tilted surface can be calculated from direct on some other plane using trigonometry, we need to have diffuse radiation on the horizontal plane available. There are regression relationships for estimating the diffuse on a tilted surface from diffuse on the horizontal. Models for estimating the diffuse on the horizontal from horizontal global that have been developed in Europe or North America have proved to be inadequate for Australia. Boland et al. developed a validated model for Australian conditions. Boland et al. detailed our recent advances in developing the theoretical framework for the use of the logistic function instead of piecewise linear or simple nonlinear functions and was the first step in identifying the means for developing a generic model for estimating diffuse from global and other predictors. We have developed a multiple predictor model, which is much simpler than previous models, and uses hourly clearness index, daily clearness index, solar altitude, apparent solar time and a measure of persistence of global radiation level as predictors. This model performs marginally better than currently used models for locations in the Northern Hemisphere and substantially better for Southern Hemisphere locations. We suggest it can be used as a universal model. (author)

  17. Finite-Time Thermoeconomic Optimization of a Solar-Driven Heat Engine Model

    Directory of Open Access Journals (Sweden)

    Fernando Angulo-Brown

    2011-01-01

    Full Text Available In the present paper, the thermoeconomic optimization of an irreversible solar-driven heat engine model has been carried out by using finite-time/finite-size thermodynamic theory. In our study we take into account losses due to heat transfer across finite time temperature differences, heat leakage between thermal reservoirs and internal irreversibilities in terms of a parameter which comes from the Clausius inequality. In the considered heat engine model, the heat transfer from the hot reservoir to the working fluid is assumed to be Dulong-Petit type and the heat transfer to the cold reservoir is assumed of the Newtonian type. In this work, the optimum performance and two design parameters have been investigated under two objective functions: the power output per unit total cost and the ecological function per unit total cost. The effects of the technical and economical parameters on the thermoeconomic performance have been also discussed under the aforementioned two criteria of performance.

  18. Modeling and verification of hemispherical solar still using ANSYS CFD

    Energy Technology Data Exchange (ETDEWEB)

    Panchal, Hitesh N. [KSV University, Gujarat Power Engineering and Research Institute, Mehsana (India); Shah, P.K. [Silver Oak College of Engineering and Technology, Ahmedabad, Gujarat (India)

    2013-07-01

    In every efficient solar still design, water temperature, vapor temperature and distillate output, and difference between water temperature and inner glass cover temperatures are very important. Here, two dimensional three phase model of hemispherical solar still is made for evaporation as well as condensation process in ANSYS CFD. Simulation results like water temperature, vapor temperature, distillate output compared with actual experimental results of climate conditions of Mehsana (latitude of 23° 59’ and longitude of 72° 38) of hemispherical solar still. Water temperature and distillate output were good agreement with actual experimental results. Study shows that ANSYS-CFD is very powerful as well as efficient tool for design, comparison purpose of hemispherical solar still.

  19. A Raster Based Approach To Solar Pressure Modeling

    Science.gov (United States)

    Wright, Theodore

    2014-01-01

    The impact of photons upon a spacecraft introduces small forces and moments. The magnitude and direction of the forces depend on the material properties of the spacecraft components being illuminated. Which components are being lit depends on the orientation of the craft with respect to the Sun as well as the gimbal angles for any significant moving external parts (solar arrays, typically). Some components may shield others from the Sun.To determine solar pressure in the presence overlapping components, a 3D model can be used to determine which components are illuminated. A view (image) of the model as seen from the Sun shows the only contributors to solar pressure. This image can be decomposed into pixels, each of which can be treated as a non-overlapping flat plate as far as solar pressure calculations are concerned. The sums of the pressures and moments on these plates approximate the solar pressure and moments on the entire vehicle.The image rasterization technique can also be used to compute other spacecraft attributes that are dependent on attitude and geometry, including solar array power generation capability and free molecular flow drag.

  20. STATISTIC MODELING OF DRYING KINETHIC OF SPINACH LEAVES USING MICROWAVE AND HOT AIR METHODS

    OpenAIRE

    Mojtaba Nouri; Marzieh Vahdani; Shilan Rashidzadeh; Lukáš Hleba; Mohammad Ali Shariati

    2015-01-01

    The target of this study was to model of spinach leaves drying using microwave and hot air dryer. This test performed in combination treatment of temperatures (50°C, 60°C, and 70°C) and microwave (90, 180, 360, 600 and 900w) in 3 replications. Sample moisture measured within drying. All the results were fitted and analyzed with 8 mathematical models base on 3 parameters including determination (R2), Chi square(X2), root mean square errors(RSME). Results also revealed that temperature and micr...

  1. Modelling of hot surface ignition within gas turbines subject to flammable gas in the intake

    DEFF Research Database (Denmark)

    Pedersen, Lea Duedahl; Nielsen, Kenny Krogh; Yin, Chungen

    2017-01-01

    Controlling risks associated with fires and explosions from leaks of flammable fluids at oil and gas facilities is paramount to ensuring safe operations. The gas turbine is a significant potential source of ignition; however, the residual risk is still not adequately understood. A model has been...... but decreases with increase in initial mixture temperature and pressure. The model shows a great potential in reliable prediction of the risk of hot surface ignition within gas turbines in the oil and gas industry. In the future, a dedicated experimental study will be performed not only to improve...

  2. Economic Model Predictive Control for Hot Water Based Heating Systems in Smart Buildings

    DEFF Research Database (Denmark)

    Awadelrahman, M. A. Ahmed; Zong, Yi; Li, Hongwei

    2017-01-01

    This paper presents a study to optimize the heating energy costs in a residential building with varying electricity price signals based on an Economic Model Predictive Controller (EMPC). The investigated heating system consists of an air source heat pump (ASHP) incorporated with a hot water tank...... as active Thermal Energy Storage (TES), where two optimization problems are integrated together to optimize both the ASHP electricity consumption and the building heating consumption utilizing a heat dynamic model of the building. The results show that the proposed EMPC can save the energy cost by load...

  3. Ductile failure analysis of high strength steel in hot forming based on micromechanical damage model

    Directory of Open Access Journals (Sweden)

    Ying Liang

    2016-01-01

    Full Text Available The damage evolution of high strength steel at elevated temperature is investigated by using the Gurson-Tvergaard-Needleman (GTN model. A hybrid method integrated thermal tensile test and numerical technique is employed to identify the damage parameters. The analysis results show that the damage parameters are different at different temperature as the variation of tested material microstructure. Furthermore, the calibrated damage parameters are implemented to simulate a bugling forming at elevated temperature. The experimental results show the availability of GTN damage model in analyzing sheet formability in hot forming.

  4. Transported PDF Modeling of Ethanol Spray in Hot-Diluted Coflow Flame

    OpenAIRE

    Ma, L.; Naud, B.; Roekaerts, D.J.E.M.

    2015-01-01

    This paper presents a numerical modeling study of one ethanol spray flame from the Delft Spray-in-Hot-Coflow (DSHC) database, which has been used to study Moderate or Intense Low-oxygen Dilution (MILD) combustion of liquid fuels (Correia Rodrigues et al. Combust. Flame 162(3), 759–773, 2015). A “Lagrangian-Lagrangian” approach is adopted where both the joint velocity-scalar Probability Density Function (PDF) for the continuous phase and the joint PDF of droplet properties are modeled and solv...

  5. Bulk viscosity of hot dense Quark matter in the PNJL model

    International Nuclear Information System (INIS)

    Xiao Shisong; Guo Panpan; Zhang Le; Hou Defu

    2014-01-01

    Starting from the Kubo formula and the QCD low energy theorem, we study the the bulk viscosity of hot dense quark matter in the PNJL model from the equation of state. We show that the bulk viscosity has a sharp peak near the chiral phase transition, and that the ratio of bulk viscosity over entropy rises dramatically in the vicinity of the phase transition. These results agree with those from the lattice and other model calculations. In addition, we show that the increase of chemical potential raises the bulk viscosity. (authors)

  6. Dynamic Modeling of Natural Convection Solar Energy Flat Plate ...

    African Journals Online (AJOL)

    The analytical solutions to the dynamic model of an air-heating flat plate solar energy thermal collector were validated by direct measurement from a physical model constructed for that purpose, of the temperatures of the cover and absorber plates, the inlet and outlet fluids, and the ambient air from morning to evening for ...

  7. Validation, Optimization and Simulation of a Solar Thermoelectric Generator Model

    Science.gov (United States)

    Madkhali, Hadi Ali; Hamil, Ali; Lee, HoSung

    2017-12-01

    This study explores thermoelectrics as a viable option for small-scale solar thermal applications. Thermoelectric technology is based on the Seebeck effect, which states that a voltage is induced when a temperature gradient is applied to the junctions of two differing materials. This research proposes to analyze, validate, simulate, and optimize a prototype solar thermoelectric generator (STEG) model in order to increase efficiency. The intent is to further develop STEGs as a viable and productive energy source that limits pollution and reduces the cost of energy production. An empirical study (Kraemer et al. in Nat Mater 10:532, 2011) on the solar thermoelectric generator reported a high efficiency performance of 4.6%. The system had a vacuum glass enclosure, a flat panel (absorber), thermoelectric generator and water circulation for the cold side. The theoretical and numerical approach of this current study validated the experimental results from Kraemer's study to a high degree. The numerical simulation process utilizes a two-stage approach in ANSYS software for Fluent and Thermal-Electric Systems. The solar load model technique uses solar radiation under AM 1.5G conditions in Fluent. This analytical model applies Dr. Ho Sung Lee's theory of optimal design to improve the performance of the STEG system by using dimensionless parameters. Applying this theory, using two cover glasses and radiation shields, the STEG model can achieve a highest efficiency of 7%.

  8. The Red Queen model of recombination hot-spot evolution: a theoretical investigation.

    Science.gov (United States)

    Latrille, Thibault; Duret, Laurent; Lartillot, Nicolas

    2017-12-19

    In humans and many other species, recombination events cluster in narrow and short-lived hot spots distributed across the genome, whose location is determined by the Zn-finger protein PRDM9. To explain these fast evolutionary dynamics, an intra-genomic Red Queen model has been proposed, based on the interplay between two antagonistic forces: biased gene conversion, mediated by double-strand breaks, resulting in hot-spot extinction, followed by positive selection favouring new PRDM9 alleles recognizing new sequence motifs. Thus far, however, this Red Queen model has not been formalized as a quantitative population-genetic model, fully accounting for the intricate interplay between biased gene conversion, mutation, selection, demography and genetic diversity at the PRDM9 locus. Here, we explore the population genetics of the Red Queen model of recombination. A Wright-Fisher simulator was implemented, allowing exploration of the behaviour of the model (mean equilibrium recombination rate, diversity at the PRDM9 locus or turnover rate) as a function of the parameters (effective population size, mutation and erosion rates). In a second step, analytical results based on self-consistent mean-field approximations were derived, reproducing the scaling relations observed in the simulations. Empirical fit of the model to current data from the mouse suggests both a high mutation rate at PRDM9 and strong biased gene conversion on its targets.This article is part of the themed issue 'Evolutionary causes and consequences of recombination rate variation in sexual organisms'. © 2017 The Authors.

  9. Large scale solar district heating. Evaluation, modelling and designing

    Energy Technology Data Exchange (ETDEWEB)

    Heller, A.

    2000-07-01

    The main objective of the research was to evaluate large-scale solar heating connected to district heating (CSDHP), to build up a simulation tool and to demonstrate the application of the tool for design studies and on a local energy planning case. The evaluation of the central solar heating technology is based on measurements on the case plant in Marstal, Denmark, and on published and unpublished data for other, mainly Danish, CSDHP plants. Evaluations on the thermal, economical and environmental performances are reported, based on the experiences from the last decade. The measurements from the Marstal case are analysed, experiences extracted and minor improvements to the plant design proposed. For the detailed designing and energy planning of CSDHPs, a computer simulation model is developed and validated on the measurements from the Marstal case. The final model is then generalised to a 'generic' model for CSDHPs in general. The meteorological reference data, Danish Reference Year, is applied to find the mean performance for the plant designs. To find the expectable variety of the thermal performance of such plants, a method is proposed where data from a year with poor solar irradiation and a year with strong solar irradiation are applied. Equipped with a simulation tool design studies are carried out spreading from parameter analysis over energy planning for a new settlement to a proposal for the combination of plane solar collectors with high performance solar collectors, exemplified by a trough solar collector. The methodology of utilising computer simulation proved to be a cheap and relevant tool in the design of future solar heating plants. The thesis also exposed the demand for developing computer models for the more advanced solar collector designs and especially for the control operation of CSHPs. In the final chapter the CSHP technology is put into perspective with respect to other possible technologies to find the relevance of the application

  10. Modelling transient temperature distribution for injecting hot water through a well to an aquifer thermal energy storage system

    Science.gov (United States)

    Yang, Shaw-Yang; Yeh, Hund-Der; Li, Kuang-Yi

    2010-10-01

    Heat storage systems are usually used to store waste heat and solar energy. In this study, a mathematical model is developed to predict both the steady-state and transient temperature distributions of an aquifer thermal energy storage (ATES) system after hot water is injected through a well into a confined aquifer. The ATES has a confined aquifer bounded by aquicludes with different thermomechanical properties and geothermal gradients along the depth. Consider that the heat is transferred by conduction and forced convection within the aquifer and by conduction within the aquicludes. The dimensionless semi-analytical solutions of temperature distributions of the ATES system are developed using Laplace and Fourier transforms and their corresponding time-domain results are evaluated numerically by the modified Crump method. The steady-state solution is obtained from the transient solution through the final-value theorem. The effect of the heat transfer coefficient on aquiclude temperature distribution is appreciable only near the outer boundaries of the aquicludes. The present solutions are useful for estimating the temperature distribution of heat injection and the aquifer thermal capacity of ATES systems.

  11. REFLECTION OF PROPAGATING SLOW MAGNETO-ACOUSTIC WAVES IN HOT CORONAL LOOPS: MULTI-INSTRUMENT OBSERVATIONS AND NUMERICAL MODELING

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, Sudip; Banerjee, Dipankar; Pant, Vaibhav [Indian Institute of Astrophysics, Koramangala, Bangalore 560034 (India); Yuan, Ding; Fang, Xia; Doorsselaere, Tom Van, E-mail: sudip@iiap.res.in, E-mail: xia.fang@wis.kuleuven.be [Centre for mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B, bus 2400, 3001, Leuven (Belgium)

    2016-09-10

    Slow MHD waves are important tools for understanding coronal structures and dynamics. In this paper, we report a number of observations from the X-Ray Telescope (XRT) on board HINODE and Solar Dynamic Observatory /Atmospheric Imaging Assembly (AIA) of reflecting longitudinal waves in hot coronal loops. To our knowledge, this is the first report of this kind as seen from the XRT and simultaneously with the AIA. The wave appears after a micro-flare occurs at one of the footpoints. We estimate the density and temperature of the loop plasma by performing differential emission measure (DEM) analysis on the AIA image sequence. The estimated speed of propagation is comparable to or lower than the local sound speed, suggesting it to be a propagating slow wave. The intensity perturbation amplitude, in every case, falls very rapidly as the perturbation moves along the loop and eventually vanishes after one or more reflections. To check the consistency of such reflection signatures with the obtained loop parameters, we perform a 2.5D MHD simulation, which uses the parameters obtained from our observation as inputs, and perform forward modeling to synthesize AIA 94 Å images. Analyzing the synthesized images, we obtain the same properties of the observables as for the real observation. From the analysis we conclude that a footpoint heating can generate a slow wave which then reflects back and forth in the coronal loop before fading. Our analysis of the simulated data shows that the main agent for this damping is anisotropic thermal conduction.

  12. SAHA-S thermodynamic model of solar plasma

    International Nuclear Information System (INIS)

    Gryaznov, V.K.; Iosilevskiy, I.L.; Fortov, V.E.; Starostin, A.N.; Roerich, V.K.; Baturin, V.A.; Ayukov, S.V.

    2013-01-01

    The model SAHA-S based on the chemical picture for the equation of state of the solar plasma is presented. The effects of Coulomb interaction, exchange and diffraction effects, free electron degeneracy, relativistic corrections, radiation pressure contributions are taken into account. The solar model based on SAHA-S taking into account extended element composition and variation of heavy element abundance is represented and discussed. The comparison of the SAHA-S equation of state data for a hydrogen plasma with the results of other models applicable to the description of the solar plasma equation of state and the results obtained with the first principle methods are demonstrated and discussed. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Constitutive Model for Hot Deformation of the Cu-Zr-Ce Alloy

    Science.gov (United States)

    Zhang, Yi; Sun, Huili; Volinsky, Alex A.; Wang, Bingjie; Tian, Baohong; Liu, Yong; Song, Kexing

    2018-02-01

    Hot compressive deformation behavior of the Cu-Zr-Ce alloy has been investigated according to the hot deformation tests in the 550-900 °C temperature range and 0.001-10 s-1 strain rate range. Based on the true stress-true strain curves, the flow stress behavior of the Cu-Zr-Ce alloy was investigated. Microstructure evolution was observed by optical microscopy. Based on the experimental results, a constitutive equation, which reflects the relationships between the stress, strain, strain rate and temperature, has been established. Material constants n, α, Q and ln A were calculated as functions of strain. The equation predicting the flow stress combined with these materials constants has been proposed. The predicted stress is consistent with experimental stress, indicating that developed constitutive equation can adequately predict the flow stress of the Cu-Zr-Ce alloy. Dynamic recrystallization critical strain was determined using the work hardening rate method. According to the dynamic material model, the processing maps for the Cu-Zr and Cu-Zr-Ce alloy were obtained at 0.4 and 0.5 strain. Based on the processing maps and microstructure observations, the optimal processing parameters for the two alloys were determined, and it was found that the addition of Ce can promote the hot workability of the Cu-Zr alloy.

  14. Modeling and optimization of a concentrated solar supercritical CO2 power plant

    Science.gov (United States)

    Osorio, Julian D.

    Renewable energy sources are fundamental alternatives to supply the rising energy demand in the world and to reduce or replace fossil fuel technologies. In order to make renewable-based technologies suitable for commercial and industrial applications, two main challenges need to be solved: the design and manufacture of highly efficient devices and reliable systems to operate under intermittent energy supply conditions. In particular, power generation technologies based on solar energy are one of the most promising alternatives to supply the world energy demand and reduce the dependence on fossil fuel technologies. In this dissertation, the dynamic behavior of a Concentrated Solar Power (CSP) supercritical CO2 cycle is studied under different seasonal conditions. The system analyzed is composed of a central receiver, hot and cold thermal energy storage units, a heat exchanger, a recuperator, and multi-stage compression-expansion subsystems with intercoolers and reheaters between compressors and turbines respectively. The effects of operating and design parameters on the system performance are analyzed. Some of these parameters are the mass flow rate, intermediate pressures, number of compression-expansion stages, heat exchangers' effectiveness, multi-tank thermal energy storage, overall heat transfer coefficient between the solar receiver and the environment and the effective area of the recuperator. Energy and exergy models for each component of the system are developed to optimize operating parameters in order to lead to maximum efficiency. From the exergy analysis, the components with high contribution to exergy destruction were identified. These components, which represent an important potential of improvement, are the recuperator, the hot thermal energy storage tank and the solar receiver. Two complementary alternatives to improve the efficiency of concentrated solar thermal systems are proposed in this dissertation: the optimization of the system's operating

  15. Origin and structures of solar eruptions II: Magnetic modeling

    Science.gov (United States)

    Guo, Yang; Cheng, Xin; Ding, MingDe

    2017-07-01

    The topology and dynamics of the three-dimensional magnetic field in the solar atmosphere govern various solar eruptive phenomena and activities, such as flares, coronal mass ejections, and filaments/prominences. We have to observe and model the vector magnetic field to understand the structures and physical mechanisms of these solar activities. Vector magnetic fields on the photosphere are routinely observed via the polarized light, and inferred with the inversion of Stokes profiles. To analyze these vector magnetic fields, we need first to remove the 180° ambiguity of the transverse components and correct the projection effect. Then, the vector magnetic field can be served as the boundary conditions for a force-free field modeling after a proper preprocessing. The photospheric velocity field can also be derived from a time sequence of vector magnetic fields. Three-dimensional magnetic field could be derived and studied with theoretical force-free field models, numerical nonlinear force-free field models, magnetohydrostatic models, and magnetohydrodynamic models. Magnetic energy can be computed with three-dimensional magnetic field models or a time series of vector magnetic field. The magnetic topology is analyzed by pinpointing the positions of magnetic null points, bald patches, and quasi-separatrix layers. As a well conserved physical quantity, magnetic helicity can be computed with various methods, such as the finite volume method, discrete flux tube method, and helicity flux integration method. This quantity serves as a promising parameter characterizing the activity level of solar active regions.

  16. Development of a solar cell model using PSCAD

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, Sergio [Polytecnic of Porto (Portugal). GECAD - ISEP; Pinto, Sonia F.; Santana, Joao J. [Instituto Superior Tecnico, Lisbon (Portugal). Dept. de Engenharia Electrotecnica e de Computadores

    2012-07-01

    This paper presents the development of a solar photovoltaic (PV) model in an electromagnetic transient software environment PSCAD/EMTDC - Power System Computer Aided Design - including a mathematical model study. The implemented model can be used for simulation studies of grid interface application. An additional algorithm has been implemented in MATLAB software in order to calculate several parameters required by the PSCAD developed model. All the simulation study has been performed in PSCAD/MATLAB software simulation tool. (orig.)

  17. Solar energy prediction and verification using operational model forecasts and ground-based solar measurements

    International Nuclear Information System (INIS)

    Kosmopoulos, P.G.; Kazadzis, S.; Lagouvardos, K.; Kotroni, V.; Bais, A.

    2015-01-01

    The present study focuses on the predictions and verification of these predictions of solar energy using ground-based solar measurements from the Hellenic Network for Solar Energy and the National Observatory of Athens network, as well as solar radiation operational forecasts provided by the MM5 mesoscale model. The evaluation was carried out independently for the different networks, for two forecast horizons (1 and 2 days ahead), for the seasons of the year, for varying solar elevation, for the indicative energy potential of the area, and for four classes of cloud cover based on the calculated clearness index (k_t): CS (clear sky), SC (scattered clouds), BC (broken clouds) and OC (overcast). The seasonal dependence presented relative rRMSE (Root Mean Square Error) values ranging from 15% (summer) to 60% (winter), while the solar elevation dependence revealed a high effectiveness and reliability near local noon (rRMSE ∼30%). An increment of the errors with cloudiness was also observed. For CS with mean GHI (global horizontal irradiance) ∼ 650 W/m"2 the errors are 8%, for SC 20% and for BC and OC the errors were greater (>40%) but correspond to much lower radiation levels (<120 W/m"2) of consequently lower energy potential impact. The total energy potential for each ground station ranges from 1.5 to 1.9 MWh/m"2, while the mean monthly forecast error was found to be consistently below 10%. - Highlights: • Long term measurements at different atmospheric cases are needed for energy forecasting model evaluations. • The total energy potential at the Greek sites presented ranges from 1.5 to 1.9 MWh/m"2. • Mean monthly energy forecast errors are within 10% for all cases analyzed. • Cloud presence results of an additional forecast error that varies with the cloud cover.

  18. Modelling and simulation of wood chip combustion in a hot air generator system.

    Science.gov (United States)

    Rajika, J K A T; Narayana, Mahinsasa

    2016-01-01

    This study focuses on modelling and simulation of horizontal moving bed/grate wood chip combustor. A standalone finite volume based 2-D steady state Euler-Euler Computational Fluid Dynamics (CFD) model was developed for packed bed combustion. Packed bed combustion of a medium scale biomass combustor, which was retrofitted from wood log to wood chip feeding for Tea drying in Sri Lanka, was evaluated by a CFD simulation study. The model was validated by the experimental results of an industrial biomass combustor for a hot air generation system in tea industry. Open-source CFD tool; OpenFOAM was used to generate CFD model source code for the packed bed combustion and simulated along with an available solver for free board region modelling in the CFD tool. Height of the packed bed is about 20 cm and biomass particles are assumed to be spherical shape with constant surface area to volume ratio. Temperature measurements of the combustor are well agreed with simulation results while gas phase compositions have discrepancies. Combustion efficiency of the validated hot air generator is around 52.2 %.

  19. An Update to the NASA Reference Solar Sail Thrust Model

    Science.gov (United States)

    Heaton, Andrew F.; Artusio-Glimpse, Alexandra B.

    2015-01-01

    An optical model of solar sail material originally derived at JPL in 1978 has since served as the de facto standard for NASA and other solar sail researchers. The optical model includes terms for specular and diffuse reflection, thermal emission, and non-Lambertian diffuse reflection. The standard coefficients for these terms are based on tests of 2.5 micrometer Kapton sail material coated with 100 nm of aluminum on the front side and chromium on the back side. The original derivation of these coefficients was documented in an internal JPL technical memorandum that is no longer available. Additionally more recent optical testing has taken place and different materials have been used or are under consideration by various researchers for solar sails. Here, where possible, we re-derive the optical coefficients from the 1978 model and update them to accommodate newer test results and sail material. The source of the commonly used value for the front side non-Lambertian coefficient is not clear, so we investigate that coefficient in detail. Although this research is primarily designed to support the upcoming NASA NEA Scout and Lunar Flashlight solar sail missions, the results are also of interest to the wider solar sail community.

  20. CFD Modeling and Experimental Validation of a Solar Still

    Directory of Open Access Journals (Sweden)

    Mahmood Tahir

    2017-01-01

    Full Text Available Earth is the densest planet of the solar system with total area of 510.072 million square Km. Over 71.68% of this area is covered with water leaving a scant area of 28.32% for human to inhabit. The fresh water accounts for only 2.5% of the total volume and the rest is the brackish water. Presently, the world is facing chief problem of lack of potable water. This issue can be addressed by converting brackish water into potable through a solar distillation process and solar still is specially assigned for this purpose. Efficiency of a solar still explicitly depends on its design parameters, such as wall material, chamber depth, width and slope of the zcondensing surface. This study was aimed at investigating the solar still parameters using CFD modeling and experimental validation. The simulation data of ANSYS-FLUENT was compared with actual experimental data. A close agreement among the simulated and experimental results was seen in the presented work. It reveals that ANSYS-FLUENT is a potent tool to analyse the efficiency of the new designs of the solar distillation systems.

  1. Development of a Performance Calculation Program for Solar Domestic Hot Water Systems with Improved Prediction of Thermal Stratification

    DEFF Research Database (Denmark)

    Fan, Jianhua; Furbo, Simon; Li, Zhe

    2016-01-01

    The transient fluid flow and heat transfer in a hot water tank during cooling caused by standby heat loss were investigated by computational fluid dynamics (CFD) calculations and by thermal measurements in previous investigation. It is elucidated how thermal stratification in the tank is influenced...... by the natural convection and how the heat loss from the tank sides will be distributed at different levels of the tank at different thermal conditions....

  2. Solar-wind predictions for the Parker Solar Probe orbit. Near-Sun extrapolations derived from an empirical solar-wind model based on Helios and OMNI observations

    Science.gov (United States)

    Venzmer, M. S.; Bothmer, V.

    2018-03-01

    Context. The Parker Solar Probe (PSP; formerly Solar Probe Plus) mission will be humanitys first in situ exploration of the solar corona with closest perihelia at 9.86 solar radii (R⊙) distance to the Sun. It will help answer hitherto unresolved questions on the heating of the solar corona and the source and acceleration of the solar wind and solar energetic particles. The scope of this study is to model the solar-wind environment for PSPs unprecedented distances in its prime mission phase during the years 2018 to 2025. The study is performed within the Coronagraphic German And US SolarProbePlus Survey (CGAUSS) which is the German contribution to the PSP mission as part of the Wide-field Imager for Solar PRobe. Aim. We present an empirical solar-wind model for the inner heliosphere which is derived from OMNI and Helios data. The German-US space probes Helios 1 and Helios 2 flew in the 1970s and observed solar wind in the ecliptic within heliocentric distances of 0.29 au to 0.98 au. The OMNI database consists of multi-spacecraft intercalibrated in situ data obtained near 1 au over more than five solar cycles. The international sunspot number (SSN) and its predictions are used to derive dependencies of the major solar-wind parameters on solar activity and to forecast their properties for the PSP mission. Methods: The frequency distributions for the solar-wind key parameters, magnetic field strength, proton velocity, density, and temperature, are represented by lognormal functions. In addition, we consider the velocity distributions bi-componental shape, consisting of a slower and a faster part. Functional relations to solar activity are compiled with use of the OMNI data by correlating and fitting the frequency distributions with the SSN. Further, based on the combined data set from both Helios probes, the parameters frequency distributions are fitted with respect to solar distance to obtain power law dependencies. Thus an empirical solar-wind model for the inner

  3. Damping width of giant dipole resonances of cold and hot nuclei: A macroscopic model

    International Nuclear Information System (INIS)

    Mughabghab, S.F.; Sonzogni, A.A.

    2002-01-01

    A phenomenological macroscopic model of the giant dipole resonance (GDR) damping width of cold and hot nuclei with ground-state spherical and near-spherical shapes is developed. The model is based on a generalized Fermi liquid model which takes into account the nuclear surface dynamics. The temperature dependence of the GDR damping width is accounted for in terms of surface and volume components. Parameter-free expressions for the damping width and the effective deformation are obtained. The model is validated with GDR measurements of the following nuclides: 39,40 K, 42 Ca, 45 Sc, 59,63 Cu, 109-120 Sn, 147 Eu, 194 Hg, and 208 Pb, and is compared with the predictions of other models

  4. Design, Modeling, Fabrication, and Evaluation of Thermoelectric Generators with Hot-Wire Chemical Vapor Deposited Polysilicon as Thermoelement Material

    Science.gov (United States)

    de Leon, Maria Theresa; Tarazona, Antulio; Chong, Harold; Kraft, Michael

    2014-11-01

    This paper presents the design, modeling, fabrication, and evaluation of thermoelectric generators (TEGs) with p-type polysilicon deposited by hot-wire chemical vapor deposition (HWCVD) as thermoelement material. A thermal model is developed based on energy balance and heat transfer equations using lumped thermal conductances. Several test structures were fabricated to allow characterization of the boron-doped polysilicon material deposited by HWCVD. The film was found to be electrically active without any post-deposition annealing. Based on the tests performed on the test structures, it is determined that the Seebeck coefficient, thermal conductivity, and electrical resistivity of the HWCVD polysilicon are 113 μV/K, 126 W/mK, and 3.58 × 10-5 Ω m, respectively. Results from laser tests performed on the fabricated TEG are in good agreement with the thermal model. The temperature values derived from the thermal model are within 2.8% of the measured temperature values. For a 1-W laser input, an open-circuit voltage and output power of 247 mV and 347 nW, respectively, were generated. This translates to a temperature difference of 63°C across the thermoelements. This paper demonstrates that HWCVD, which is a cost-effective way of producing solar cells, can also be applied in the production of TEGs. By establishing that HWCVD polysilicon can be an effective thermoelectric material, further work on developing photovoltaic-thermoelectric (PV-TE) hybrid microsystems that are cost-effective and better performing can be explored.

  5. Diffuse solar radiation estimation models for Turkey's big cities

    International Nuclear Information System (INIS)

    Ulgen, Koray; Hepbasli, Arif

    2009-01-01

    A reasonably accurate knowledge of the availability of the solar resource at any place is required by solar engineers, architects, agriculturists, and hydrologists in many applications of solar energy such as solar furnaces, concentrating collectors, and interior illumination of buildings. For this purpose, in the past, various empirical models (or correlations) have been developed in order to estimate the solar radiation around the world. This study deals with diffuse solar radiation estimation models along with statistical test methods used to statistically evaluate their performance. Models used to predict monthly average daily values of diffuse solar radiation are classified in four groups as follows: (i) From the diffuse fraction or cloudness index, function of the clearness index, (ii) From the diffuse fraction or cloudness index, function of the relative sunshine duration or sunshine fraction, (iii) From the diffuse coefficient, function of the clearness index, and (iv) From the diffuse coefficient, function of the relative sunshine duration or sunshine fraction. Empirical correlations are also developed to establish a relationship between the monthly average daily diffuse fraction or cloudness index (K d ) and monthly average daily diffuse coefficient (K dd ) with the monthly average daily clearness index (K T ) and monthly average daily sunshine fraction (S/S o ) for the three big cities by population in Turkey (Istanbul, Ankara and Izmir). Although the global solar radiation on a horizontal surface and sunshine duration has been measured by the Turkish State Meteorological Service (STMS) over all country since 1964, the diffuse solar radiation has not been measured. The eight new models for estimating the monthly average daily diffuse solar radiation on a horizontal surface in three big cites are validated, and thus, the most accurate model is selected for guiding future projects. The new models are then compared with the 32 models available in the

  6. Coherent and incoherent J /ψ photonuclear production in an energy-dependent hot-spot model

    Science.gov (United States)

    Cepila, J.; Contreras, J. G.; Krelina, M.

    2018-02-01

    In a previous publication, we have presented a model for the photoproduction of J /ψ vector mesons off protons, where the proton structure in the impact-parameter plane is described by an energy-dependent hot-spot profile. Here we extend this model to study the photonuclear production of J /ψ vector mesons in coherent and incoherent interactions of heavy nuclei. We study two methods to extend the model to the nuclear case: using the standard Glauber-Gribov formalism and using geometric scaling to obtain the nuclear saturation scale. We find that the incoherent cross section changes sizably with the inclusion of subnucleonic hot spots and that this change is energy dependent. We propose to search for this behavior by measuring the ratio of the incoherent to coherent cross sections at different energies. We compare the results of our model to results from the Relativistic Heavy-Ion Collider (RHIC) and from run 1 at the Large Hadron Collider (LHC), finding satisfactory agreement. We also present predictions for the LHC at the new energies reached in run 2. The predictions include J /ψ production in ultraperipheral collisions, as well as the recently observed photonuclear production in peripheral collisions.

  7. Golden Rays - July 2017 | Solar Research | Solar Research | NREL

    Science.gov (United States)

    , subscribe to the Solar Newsletter. SUBSCRIBE Hot Topics Two solar installers secure solar panels on the roof that has the potential to improve the efficiency of solar panels while leveraging existing

  8. Curve fitting methods for solar radiation data modeling

    Energy Technology Data Exchange (ETDEWEB)

    Karim, Samsul Ariffin Abdul, E-mail: samsul-ariffin@petronas.com.my, E-mail: balbir@petronas.com.my; Singh, Balbir Singh Mahinder, E-mail: samsul-ariffin@petronas.com.my, E-mail: balbir@petronas.com.my [Department of Fundamental and Applied Sciences, Faculty of Sciences and Information Technology, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak Darul Ridzuan (Malaysia)

    2014-10-24

    This paper studies the use of several type of curve fitting method to smooth the global solar radiation data. After the data have been fitted by using curve fitting method, the mathematical model of global solar radiation will be developed. The error measurement was calculated by using goodness-fit statistics such as root mean square error (RMSE) and the value of R{sup 2}. The best fitting methods will be used as a starting point for the construction of mathematical modeling of solar radiation received in Universiti Teknologi PETRONAS (UTP) Malaysia. Numerical results indicated that Gaussian fitting and sine fitting (both with two terms) gives better results as compare with the other fitting methods.

  9. Curve fitting methods for solar radiation data modeling

    Science.gov (United States)

    Karim, Samsul Ariffin Abdul; Singh, Balbir Singh Mahinder

    2014-10-01

    This paper studies the use of several type of curve fitting method to smooth the global solar radiation data. After the data have been fitted by using curve fitting method, the mathematical model of global solar radiation will be developed. The error measurement was calculated by using goodness-fit statistics such as root mean square error (RMSE) and the value of R2. The best fitting methods will be used as a starting point for the construction of mathematical modeling of solar radiation received in Universiti Teknologi PETRONAS (UTP) Malaysia. Numerical results indicated that Gaussian fitting and sine fitting (both with two terms) gives better results as compare with the other fitting methods.

  10. Curve fitting methods for solar radiation data modeling

    International Nuclear Information System (INIS)

    Karim, Samsul Ariffin Abdul; Singh, Balbir Singh Mahinder

    2014-01-01

    This paper studies the use of several type of curve fitting method to smooth the global solar radiation data. After the data have been fitted by using curve fitting method, the mathematical model of global solar radiation will be developed. The error measurement was calculated by using goodness-fit statistics such as root mean square error (RMSE) and the value of R 2 . The best fitting methods will be used as a starting point for the construction of mathematical modeling of solar radiation received in Universiti Teknologi PETRONAS (UTP) Malaysia. Numerical results indicated that Gaussian fitting and sine fitting (both with two terms) gives better results as compare with the other fitting methods

  11. Conductive solar wind models in rapidly diverging flow geometries

    International Nuclear Information System (INIS)

    Holzer, T.E.; Leer, E.

    1980-01-01

    A detailed parameter study of conductive models of the solar wind has been carried out, extending the previous similar studies of Durney (1972) and Durney and Hundhausen (1974) by considering collisionless inhibition of thermal conduction, rapidly diverging flow geometries, and the structure of solutions for the entire n 0 -T 0 plane (n 0 and T 0 are the coronal base density and temperature). Primary emphasis is placed on understanding the complex effects of the physical processes operative in conductive solar wind models. There are five points of particular interest that have arisen from the study: (1) neither collisionless inhibition of thermal conduction nor rapidly diverging flow geometries can significantly increase the solar wind speed at 1 AU; (2) there exists a firm upper limit on the coronal base temperature consistent with observed values of the coronal base pressure and solar wind mass flux density; (3) the principal effect of rapidly diverging flow geometries is a decrease in the solar wind mass flux density at 1 AU and an increase in the mass flux density at the coronal base; (4) collisionless inhibition of thermal conduction can lead to a solar wind flow speed that either increases or decreases with increasing coronal base density (n 0 ) and temperature (T 0 , depending on the region of the n 0 -T 0 plane considered; (5) there is a region of the n 0 -T/sub o/ plane at high coronal base densities where low-speed, high-mass-flux, transonic solar wind flows exist: a region not previously considered

  12. Modelling of solar energy potential in Nigeria using an artificial neural network model

    International Nuclear Information System (INIS)

    Fadare, D.A.

    2009-01-01

    In this study, an artificial neural network (ANN) based model for prediction of solar energy potential in Nigeria (lat. 4-14 o N, log. 2-15 o E) was developed. Standard multilayered, feed-forward, back-propagation neural networks with different architecture were designed using neural toolbox for MATLAB. Geographical and meteorological data of 195 cities in Nigeria for period of 10 years (1983-1993) from the NASA geo-satellite database were used for the training and testing the network. Meteorological and geographical data (latitude, longitude, altitude, month, mean sunshine duration, mean temperature, and relative humidity) were used as inputs to the network, while the solar radiation intensity was used as the output of the network. The results show that the correlation coefficients between the ANN predictions and actual mean monthly global solar radiation intensities for training and testing datasets were higher than 90%, thus suggesting a high reliability of the model for evaluation of solar radiation in locations where solar radiation data are not available. The predicted solar radiation values from the model were given in form of monthly maps. The monthly mean solar radiation potential in northern and southern regions ranged from 7.01-5.62 to 5.43-3.54 kW h/m 2 day, respectively. A graphical user interface (GUI) was developed for the application of the model. The model can be used easily for estimation of solar radiation for preliminary design of solar applications.

  13. Mathematical model development for a new solar desalination system (SDS)

    Energy Technology Data Exchange (ETDEWEB)

    Elsafty, A.F. [Arab Academy for Science and Technology and Maritime Transport, Alexandria (Egypt). Dept. of Mechanical and Marine Engineering; Fath, H.E. [Alexandria Univ., Alexandria (Egypt). Dept. of Mechanical Engineering

    2007-07-01

    Desalination, as a non-conventional water resource, has become one of the most promising alternative water sources to address the fresh water shortage in the near future. Desalination technologies are constrained in that they are driven almost entirely by the combustion of fuels which are still of finite supply, pollute the air, and contribute to the risk of global climate change. Solar distillation is preferred to other processes of distillation because of the low operating cost, low maintenance, lack of moving parts, and clean energy offered. The development of solar distillation has demonstrated its suitability for saline water desalination when weather conditions are favorable and when demand is not large. Solar energy in the Arab region is available at relatively high intensity during most of the year. This paper presented a general mathematical model for a newly developed solar still that uses a parabolic reflector-tube absorber desalination technology. A computer program was developed to simulate the still operation and to solve the governing heat and mass transfer action which occurred during the operation. The program was used to study the still production in different cases. The paper provided a description of the mathematical model and discussed the governing equations. It was concluded that unit productivity improved by increasing the solar intensity, ambient temperature, efficiency of reflector material, reflector aperture area and evaporation area. In addition, increasing the wind velocity, saline water depth, condenser emissivity and condenser thickness had only a small effect on the productivity. 3 refs., 1 tab., 14 figs.

  14. How "Hot Precursors" Modify Island Nucleation: A Rate-Equation Model

    Science.gov (United States)

    Morales-Cifuentes, Josue R.; Einstein, T. L.; Pimpinelli, A.

    2014-12-01

    We propose a novel island nucleation and growth model explicitly including transient (ballistic) mobility of the monomers deposited at rate F , assumed to be in a hot precursor state before thermalizing. In limiting regimes, corresponding to fast (diffusive) and slow (ballistic) thermalization, the island density N obeys scaling N ∝Fα . In between is found a rich, complex behavior, with various distinctive scaling regimes, characterized by effective exponents αeff and activation energies that we compute exactly. Application to N (F ,T ) of recent organic-molecule deposition experiments yields an excellent fit.

  15. Application of thermodynamics and Wagner model on two problems in continuous hot-dip galvanizing

    Science.gov (United States)

    Liu, Huachu; He, Yanlin; Li, Lin

    2009-12-01

    Firstly in this paper, the influence of H 2 and water vapor content on selective oxidation occurred in continuous hot-dip galvanizing has been studied by thermodynamics and Wagner model, then, the Gibbs energy of each possible aluminothermic reducing reaction in zinc bath was calculated in order to judge the possibility of these reactions. It was found that oxides' amounts and oxidation type were greatly related to the H 2 and water content in the annealing atmosphere. And from the view of thermodynamics, surface oxides (MnO, Cr 2O 3, SiO 2 etc.) can be reduced by the effective Al in Zn bath.

  16. Self-organization of hot plasmas the canonical profile transport model

    CERN Document Server

    Dnestrovskij, Yu N

    2015-01-01

    In this monograph the author presents the Canonical Profile Transport Model or CPTM as a rather general mathematical framework to simulate plasma discharges.The description of hot plasmas in a magnetic fusion device is a very challenging task and many plasma properties still lack a physical explanation. One important property is plasma self-organization.It is very well known from experiments that the radial profile of the plasma pressure and temperature remains rather unaffected by changes of the deposited power or plasma density. The attractiveness of the CPTM is that it includes the effect o

  17. Phenomenological Model Describing the Formation of Peeling Defects on Hot-Rolled Duplex Stainless Steel 2205

    Science.gov (United States)

    Yong-jun, Zhang; Hui, Zhang; Jing-tao, Han

    2017-05-01

    The chemical composition, morphology, and microstructure of peeling defects formed on the surface of sheets from steel 2205 under hot rolling are studied. The microstructure of the surface is analyzed using scanning electron and light microscopy. The zones affected are shown to contain nonmetallic inclusions of types Al2O3 and CaO - SiO2 - Al2O3 - MgO in the form of streak precipitates and to have an unfavorable content of austenite, which causes decrease in the ductility of the area. The results obtained are used to derive a five-stage phenomenological model of formation of such defects.

  18. Modeling ethanol spray jet flame in hot-diluted coflow with transported PDF

    OpenAIRE

    Ma, L.; Naud, B.; Roekaerts, D.J.E.M.

    2014-01-01

    MILD Combustion, also known as flameless combustion, is attracting wide scientific interest due to its potential of high efficiency and low NOx emission. This paper focuses on the numerical modeling of one of the ethanol spray flame cases from the Delft Spray-in-Hot-Coflow (DSHC) burner, which has been used to study MILD oxidation of liquid fuels. The study has been carried out following the approach of dilute spray simulation. To properly account the turbulent two-phase flow system, a joint ...

  19. Topology of large-scale structure in seeded hot dark matter models

    Science.gov (United States)

    Beaky, Matthew M.; Scherrer, Robert J.; Villumsen, Jens V.

    1992-01-01

    The topology of the isodensity surfaces in seeded hot dark matter models, in which static seed masses provide the density perturbations in a universe dominated by massive neutrinos is examined. When smoothed with a Gaussian window, the linear initial conditions in these models show no trace of non-Gaussian behavior for r0 equal to or greater than 5 Mpc (h = 1/2), except for very low seed densities, which show a shift toward isolated peaks. An approximate analytic expression is given for the genus curve expected in linear density fields from randomly distributed seed masses. The evolved models have a Gaussian topology for r0 = 10 Mpc, but show a shift toward a cellular topology with r0 = 5 Mpc; Gaussian models with an identical power spectrum show the same behavior.

  20. Empirical Modeling on Hot Air Drying of Fresh and Pre-treated Pineapples

    Directory of Open Access Journals (Sweden)

    Tanongkankit Yardfon

    2016-01-01

    Full Text Available This research was aimed to study drying kinetics and determine empirical model of fresh pineapple and pre-treated pineapple with sucrose solution at different concentrations during drying. 3 mm thick samples were immersed into 30, 40 and 50 Brix of sucrose solution before hot air drying at temperatures of 60, 70 and 80°C. The empirical models to predict the drying kinetics were investigated. The results showed that the moisture content decreased when increasing the drying temperatures and times. Increase in sucrose concentration led to longer drying time. According to the statistical values of the highest coefficients (R2, the lowest least of chi-square (χ2 and root mean square error (RMSE, Logarithmic model was the best models for describing the drying behavior of soaked samples into 30, 40 and 50 Brix of sucrose solution.

  1. Solar-Powered Desalination: A Modelling and Experimental Study

    Science.gov (United States)

    Leblanc, Jimmy; Andrews, John

    2007-10-01

    Water shortage is becoming one of the major problems worldwide. As such, desalination technologies have been implemented to meet growing demands for fresh water. Among the desalination technologies, thermal desalination, including multi stage flash (MSF) and multi effect evaporation (MEE), is the current leading desalination process. Reverse osmosis (RO) is also being increasingly used. Despite technological improvements, thermal desalination and reverse osmosis continue to be intensive fossil-fuel consumers and contribute to increased levels of greenhouse gases. As energy costs rise, thermal desalination by solar energy and/or low cost waste heat is likely to become increasingly attractive. As part of a project investigating the productive use of saline land and the development of sustainable desalination systems, the feasibility of producing potable water from seawater or brackish water using desalination systems powered by renewable energy in the form of low-temperature solar-thermal sources has been studied. A salinity-gradient solar pond and an evacuated tube solar collector system have been used as heat sources. Solar ponds combine solar energy collection with long-term storage and can provide reliable thermal energy at temperature ranges from 50 to 90 °C. A visual basic computer model of the different multi-stage flash desalination processes coupled with a salinity-gradient solar pond was developed to determine which process is preferable in regards to performance and greenhouse impact. The governing mathematical equations are derived from mass balances, heat energy balances, and heat transfer characteristics. Using the results from the modelling, a small-scale solar-powered desalination system, capable of producing up to 500 litres of fresh water per day, was designed and manufactured. This single-stage flash system consists of two main units: the heat supply and storage system and the flash desalination unit. Two different condenser heat exchanger

  2. How Hot Precursor Modify Island Nucleation: A Rate-Equation Model

    Science.gov (United States)

    Morales-Cifuentes, Josue; Einstein, T. L.; Pimpinelli, Alberto

    2015-03-01

    We describe the analysis, based on rate equations, of the hot precursor model mentioned in the previous talk. Two key parameters are the competing times of ballistic monomers decaying into thermalized monomers vs. being captured by an island, which naturally define a ``thermalization'' scale for the system. We interpret the energies and dimmensionless parameters used in the model, and provide both an implicit analytic solution and a convenient asymptotic approximation. Further analysis reveals novel scaling regimes and nonmonotonic crossovers between them. To test our model, we applied it to experiments on parahexaphenyl (6P) on sputtered mica. With the resulting parameters, the curves derived from our analytic treatment account very well for the data at the 4 different temperatures. The fit shows that the high-flux regime corresponds not to ALA (attachment-limited aggregation) or HMA (hot monomer aggregation) but rather to an intermediate scaling regime related to DLA (diffusion-limited aggregation). We hope this work stimulates further experimental investigations. Work at UMD supported by NSF CHE 13-05892.

  3. Modeling of the flow behavior of SAE 8620H combing microstructure evolution in hot forming

    Science.gov (United States)

    Fu, Xiaobin; Wang, Baoyu; Tang, Xuefeng

    2017-10-01

    With the development of net-shape forming technology, hot forming process is widely applied to manufacturing gear parts, during which, materials suffer severe plastic distortion and microstructure changes continually. In this paper, to understand and model the flow behavior and microstructure evolution, SAE 8620H, a widely used gear steel, is selected as the object and the flow behavior and microstructure evolution are observed by an isothermal hot compression tests at 1273-1373 K with a strain rate of 0.1-10 s-1. Depending on the results of the compression test, a set of internal-state-variable based unified constitutive equations is put forward to describe the flow behavior and microstructure evaluation of SAE 8620H. Moreover, the evaluation of the dislocation density and the fraction of dynamic recrystallization based on the theory of thermal activation is modeled and reincorporated into the constitutive law. The material parameters in the constitutive model are calculated based on the measured flow stress and dynamic recrystallization fraction. The predicted flow stress under different deformation conditions has a good agreement with the measured results.

  4. Regression Model to Predict Global Solar Irradiance in Malaysia

    Directory of Open Access Journals (Sweden)

    Hairuniza Ahmed Kutty

    2015-01-01

    Full Text Available A novel regression model is developed to estimate the monthly global solar irradiance in Malaysia. The model is developed based on different available meteorological parameters, including temperature, cloud cover, rain precipitate, relative humidity, wind speed, pressure, and gust speed, by implementing regression analysis. This paper reports on the details of the analysis of the effect of each prediction parameter to identify the parameters that are relevant to estimating global solar irradiance. In addition, the proposed model is compared in terms of the root mean square error (RMSE, mean bias error (MBE, and the coefficient of determination (R2 with other models available from literature studies. Seven models based on single parameters (PM1 to PM7 and five multiple-parameter models (PM7 to PM12 are proposed. The new models perform well, with RMSE ranging from 0.429% to 1.774%, R2 ranging from 0.942 to 0.992, and MBE ranging from −0.1571% to 0.6025%. In general, cloud cover significantly affects the estimation of global solar irradiance. However, cloud cover in Malaysia lacks sufficient influence when included into multiple-parameter models although it performs fairly well in single-parameter prediction models.

  5. AISI/DOE Advanced Process Control Program Vol. 3 of 6: MICROSTRUCTURAL ENGINEERING IN HOT-STRIP MILLS Part 2 of 2: Constitutive Behavior Modeling of Steels Under Hot-Rolling Conditions; FINAL

    International Nuclear Information System (INIS)

    Yi-Wen Cheng; Patrick Purtscher

    1999-01-01

    This report describes the development of models for predicting (1) constitutive behaviors and (2) mechanical properties of hot-rolled steels as functions of chemical composition, microstructural features, and processing variables. The study includes the following eight steels: A36, DQSK, HSLA-V, HSLA-Nb, HSLA-50/Ti-Nb, and two interstitial-free (IF) grades. These developed models have been integrated into the Hot-Strip Mill Model (HSMM), which simulates the hot strip rolling mills and predicts the mechanical properties of hot-rolled products. The HSMM model has been developed by the University of British Columbia-Canada as a part of project on the microstructural engineering in hot-strip mills

  6. new model for solar radiation estimation from measured air

    African Journals Online (AJOL)

    HOD

    RMSE) and correlation ... countries due to the unavailability of measured data in place [3-5]. ... models were used to predict solar radiation in Nigeria by. [12-15]. However ..... "Comparison of Gene Expression Programming with neuro-fuzzy and ...

  7. Improving Perovskite Solar Cells: Insights From a Validated Device Model

    NARCIS (Netherlands)

    Sherkar, Tejas S.; Momblona, Cristina; Gil-Escrig, Lidon; Bolink, Henk J.; Koster, L. Jan Anton

    2017-01-01

    To improve the efficiency of existing perovskite solar cells (PSCs), a detailed understanding of the underlying device physics during their operation is essential. Here, a device model has been developed and validated that describes the operation of PSCs and quantitatively explains the role of

  8. Empirical Models for the Estimation of Global Solar Radiation in ...

    African Journals Online (AJOL)

    Empirical Models for the Estimation of Global Solar Radiation in Yola, Nigeria. ... and average daily wind speed (WS) for the interval of three years (2010 – 2012) measured using various instruments for Yola of recorded data collected from the Center for Atmospheric Research (CAR), Anyigba are presented and analyzed.

  9. Students to Race Solar-Powered Model Cars

    Science.gov (United States)

    race model solar cars on Saturday, May 12. The cars, designed to tap into energy from the sun, are than 12 inches wide, 24 inches long and 12 inches high. The 20-meter race is a double elimination competition with awards going to the five fastest cars. Five design awards also will be given out for

  10. Large scale solar district heating. Evaluation, modelling and designing - Appendices

    Energy Technology Data Exchange (ETDEWEB)

    Heller, A.

    2000-07-01

    The appendices present the following: A) Cad-drawing of the Marstal CSHP design. B) Key values - large-scale solar heating in Denmark. C) Monitoring - a system description. D) WMO-classification of pyranometers (solarimeters). E) The computer simulation model in TRNSYS. F) Selected papers from the author. (EHS)

  11. Mainstreaming solar : Stretching the regulatory regime through business model innovation

    NARCIS (Netherlands)

    Huijben, J.C.C.M.; Verbong, G.P.J.; Podoynitsyna, K.S.

    This paper explores how the regulatory regime for Solar PV, defined as a combination of niche shielding and mainstream regulations, affects niche business models, using the Dutch and Flemish regulatory regimes as examples. The regulatory regime does not influence all components of the business

  12. Uncertainty Model for Total Solar Irradiance Estimation on Australian Rooftops

    Science.gov (United States)

    Al-Saadi, Hassan; Zivanovic, Rastko; Al-Sarawi, Said

    2017-11-01

    The installations of solar panels on Australian rooftops have been in rise for the last few years, especially in the urban areas. This motivates academic researchers, distribution network operators and engineers to accurately address the level of uncertainty resulting from grid-connected solar panels. The main source of uncertainty is the intermittent nature of radiation, therefore, this paper presents a new model to estimate the total radiation incident on a tilted solar panel. Where a probability distribution factorizes clearness index, the model is driven upon clearness index with special attention being paid for Australia with the utilization of best-fit-correlation for diffuse fraction. The assessment of the model validity is achieved with the adoption of four goodness-of-fit techniques. In addition, the Quasi Monte Carlo and sparse grid methods are used as sampling and uncertainty computation tools, respectively. High resolution data resolution of solar irradiations for Adelaide city were used for this assessment, with an outcome indicating a satisfactory agreement between actual data variation and model.

  13. Solar PV Manufacturing Cost Model Group: Installed Solar PV System Prices (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Goodrich, A. C.; Woodhouse, M.; James, T.

    2011-02-01

    EERE's Solar Energy Technologies Program is charged with leading the Secretary's SunShot Initiative to reduce the cost of electricity from solar by 75% to be cost competitive with conventional energy sources without subsidy by the end of the decade. As part of this Initiative, the program has funded the National Renewable Energy Laboratory (NREL) to develop module manufacturing and solar PV system installation cost models to ensure that the program's cost reduction targets are carefully aligned with current and near term industry costs. The NREL cost analysis team has leveraged the laboratories' extensive experience in the areas of project finance and deployment, as well as industry partnerships, to develop cost models that mirror the project cost analysis tools used by project managers at leading U.S. installers. The cost models are constructed through a "bottoms-up" assessment of each major cost element, beginning with the system's bill of materials, labor requirements (type and hours) by component, site-specific charges, and soft costs. In addition to the relevant engineering, procurement, and construction costs, the models also consider all relevant costs to an installer, including labor burdens and overhead rates, supply chain costs, and overhead and materials inventory costs, and assume market-specific profits.

  14. COLLAPSING HOT MOLECULAR CORES: A MODEL FOR THE DUST SPECTRUM AND AMMONIA LINE EMISSION OF THE G31.41+0.31 HOT CORE

    International Nuclear Information System (INIS)

    Osorio, Mayra; Anglada, Guillem; Lizano, Susana; D'Alessio, Paola

    2009-01-01

    We present a model aimed to reproduce the observed spectral energy distribution (SED) as well as the ammonia line emission of the G31.41+0.31 hot core. The hot core is modeled as an infalling envelope onto a massive star that is undergoing an intense accretion phase. We assume an envelope with a density and velocity structure resulting from the dynamical collapse of a singular logatropic sphere. The stellar and envelope physical properties are determined by fitting the observed SED. From these physical conditions, the emerging ammonia line emission is calculated and compared with subarcsecond resolution VLA data of the (4,4) transition taken from the literature. The only free parameter in this line fitting is the ammonia abundance. The observed intensities of the main and satellite ammonia (4,4) lines and their spatial distribution can be well reproduced provided the steep increase of the gas-phase ammonia abundance in the hotter (>100 K), inner regions of the core produced by the sublimation of icy mantles where ammonia molecules are trapped is taken into account. The model predictions for the (2,2), (4,4), and (5,5) transitions, obtained with the same set of parameters, are also reasonably in agreement, given the observational uncertainties, with the single-dish spectra of the region available in the literature. The best fit is obtained for a model with a central star of ∼25M sun , a mass accretion rate of ∼3 x 10 -3 M sun yr -1 , and a total luminosity of ∼2 x 10 5 L sun . The outer radius of the envelope is 30,000 AU, where kinetic temperatures as high as ∼40 K are reached. The gas-phase ammonia abundance ranges from ∼2 x 10 -8 in the outer region to ∼3 x 10 -6 in the inner region. To our knowledge, this is the first time that the dust and molecular line data of a hot molecular core, including subarcsecond resolution data that spatially resolve the structure of the core, have been simultaneously explained by a detailed, physically self

  15. Who's hot, who's not? Effects of concentrating solar power heliostats on soil temperature at Ivanpah Solar Electric Generating System, Mojave Desert, USA

    Science.gov (United States)

    Grodsky, S.; Hernandez, R. R.

    2017-12-01

    Solar energy development may function as a contemporary, anthropogenic driver of disturbance when sited in natural ecosystems. Orientation and density of solar modules, including heliostats at concentrating solar power (CSP) facilities, may affect soils via shading and altered surface-water flow. Meanwhile, soil attributes like temperature and moisture may affect nutrient cycling, plant germination and growth, and soil biota. We tested effects of CSP heliostats on soil temperature at Ivanpah Solar Electric Generating System (ISEGS) in the Mojave Desert, USA. We implemented experimental treatments based on preconstruction rare plant [e.g., Mojave milkweed (Asclepias nyctaginifolia)] protection areas (hereafter "halos"), site preparation activities, and heliostat density throughout three, replicated CSP blocks (i.e., tower and associated heliostats), including: (1) No Halos (Bladed) - high site preparation intensity, high heliostat density immediately surrounding towers; (2) No Halos (Mowed) - moderate site preparation intensity, moderate to low heliostat density as distance increases from towers; and (3) Halos - no site preparation, no heliostats. We also established control sites within 1,600 km of ISEGS in undisturbed desert. We observed significant differences in soil temperature across treatments. We recorded significantly lower soil temperatures in the No Halos (Bladed) treatments (26.7°C) and No Halos (Mowed) treatments (29.9°C) than in the Halos treatments (32.9°C) and controls (32.1°C). We also determined that soil temperatures in the Halos treatments and controls did not significantly differ. Our results indicated that shading from high-density heliostat configuration significantly reduced soil temperature relative to low-density heliostat configuration and areas without CSP. Shading from heliostats and consequential fluctuation in soil temperatures may affect local-scale distribution of flora and fauna, leading to altered "bottom-up" ecological

  16. Thermal hydrodynamic modeling and simulation of hot-gas duct for next-generation nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Injun [School of Mechanical Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Hong, Sungdeok; Kim, Chansoo [Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Bai, Cheolho; Hong, Sungyull [School of Mechanical Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Shim, Jaesool, E-mail: jshim@ynu.ac.kr [School of Mechanical Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of)

    2016-12-15

    Highlights: • Thermal hydrodynamic nonlinear model is presented to examine a hot gas duct (HGD) used in a fourth-generation nuclear power reactor. • Experiments and simulation were compared to validate the nonlinear porous model. • Natural convection and radiation are considered to study the effect on the surface temperature of the HGD. • Local Nusselt number is obtained for the optimum design of a possible next-generation HGD. - Abstract: A very high-temperature gas-cooled reactor (VHTR) is a fourth-generation nuclear power reactor that requires an intermediate loop that consists of a hot-gas duct (HGD), an intermediate heat exchanger (IHX), and a process heat exchanger for massive hydrogen production. In this study, a mathematical model and simulation were developed for the HGD in a small-scale nitrogen gas loop that was designed and manufactured by the Korea Atomic Energy Research Institute. These were used to investigate the effect of various important factors on the surface of the HGD. In the modeling, a porous model was considered for a Kaowool insulator inside the HGD. The natural convection and radiation are included in the model. For validation, the modeled external surface temperatures are compared with experimental results obtained while changing the inlet temperatures of the nitrogen working fluid. The simulation results show very good agreement with the experiments. The external surface temperatures of the HGD are obtained with respect to the porosity of insulator, emissivity of radiation, and pressure of the working fluid. The local Nusselt number is also obtained for the optimum design of a possible next-generation HGD.

  17. Comparative modeling of InP solar cell structures

    Science.gov (United States)

    Jain, R. K.; Weinberg, I.; Flood, D. J.

    1991-01-01

    The comparative modeling of p(+)n and n(+)p indium phosphide solar cell structures is studied using a numerical program PC-1D. The optimal design study has predicted that the p(+)n structure offers improved cell efficiencies as compared to n(+)p structure, due to higher open-circuit voltage. The various cell material and process parameters to achieve the maximum cell efficiencies are reported. The effect of some of the cell parameters on InP cell I-V characteristics was studied. The available radiation resistance data on n(+)p and p(+)p InP solar cells are also critically discussed.

  18. Photon absorption models in nanostructured semiconductor solar cells and devices

    CERN Document Server

    Luque, Antonio

    2015-01-01

    This book is intended to be used by materials and device physicists and also solar cells researchers. It models the performance characteristics of nanostructured solar cells and resolves the dynamics of transitions between several levels of these devices. An outstanding insight into the physical behaviour of these devices is provided, which complements experimental work. This therefore allows a better understanding of the results, enabling the development of new experiments and optimization of new devices. It is intended to be accessible to researchers, but also to provide engineering tools w

  19. Particle-in-cell studies of laser-driven hot spots and a statistical model for mesoscopic properties of Raman backscatter

    International Nuclear Information System (INIS)

    Albright, B.J.; Yin, L.; Bowers, K.J.; Kline, J.L.; Montgomery, D.S.; Fernandez, J.C.; Daughton, W.

    2006-01-01

    The authors use explicit particle-in-cell simulations to model stimulated scattering processes in media with both solitary and multiple laser hot spots. These simulations indicate coupling among hot spots, whereby scattered light, plasma waves, and hot electrons generated in one laser hot spot may propagate to neighboring hot spots, which can be destabilized to enhanced backscatter. A nonlinear statistical model of a stochastic beam exhibiting this coupled behavior is described here. Calibration of the model using particle-in-cell simulations is performed, and a threshold is derived for 'detonation' of the beam to high reflectivity. (authors)

  20. Solar g-modes? Comparison of detected asymptotic g-mode frequencies with solar model predictions

    Science.gov (United States)

    Wood, Suzannah Rebecca; Guzik, Joyce Ann; Mussack, Katie; Bradley, Paul A.

    2018-06-01

    After many years of searching for solar gravity modes, Fossat et al. (2017) reported detection of the nearly equally spaced high-order g-modes periods using a 15-year time series of GOLF data from the SOHO spacecraft. Here we report progress towards and challenges associated with calculating and comparing g-mode period predictions for several previously published standard solar models using various abundance mixtures and opacities, as well as the predictions for some non-standard models incorporating early mass loss, and compare with the periods reported by Fossat et al (2017). Additionally, we have a side-by-side comparison of results of different stellar pulsation codes for calculating g-mode predictions. These comparisons will allow for testing of nonstandard physics input that affect the core, including an early more massive Sun and dynamic electron screening.