Sample records for convectors

  1. Air Distribution in Rooms with a Fan-Driven Convector

    DEFF Research Database (Denmark)

    Larsen, Tine Steen; Bindels, Rob H.W.; Michalak, Lukasz


    Experiments with a fan-driven convector used for both heating and cooling are de.scribed in this paper. Only the cooling situation is considered. The convector is positioned in the upper corner ofthe room, and from there the cold air is let out through the device along the ceiling. The airflow...... coming from the dijfuser is partly controlled by the momentum flow and partly from gravity forces, where the thermal load in the room and the temperature difference between room air and supply air affect the airflow from the convector. The convector system was tested in the same test room in which many...... regular ventilation systems were tested earlier to be ahle to compare airflow from the convector .system with regular ventilation ,systems at a later stage of this research. The heat load in the room consists of a thermal manikin sitting at a desk, a computer, and a desk lamp producing a total heat load...

  2. New computer-assisted design of blower convectors; Neue computerunterstuetzte Auslegung von Geblaesekonvektoren

    Energy Technology Data Exchange (ETDEWEB)

    Enzensperger, M. [Axair GmbH, Garching-Hochbrueck (Germany)


    The problem is well-known: in the air conditioning market, an increasing trends towards blower convectors has emerged recently. Often the devices are exactly tailored to special applications, requiring accurate rating. The design of blower convectors must correspond to planning specifications. The available technical data deviate from the standard data sheets of manufacturers. (orig.) [German] Wer kennt das Problem nicht: In letzter Zeit ist auf dem Klimamarkt ein verstaerkter Trend zu Geblaesekonvektoren festzustellen. Die Projekte werden oft speziell auf die Anwendungsfaelle zugeschnitten und erfordern eine genauere Auslegung. Gemaess den Angaben eines Planers muss ein Geblaesekonvektor ausgelegt werden. Die vorliegenden technischen Daten weichen von den Standard-Herstellerangaben ab. (orig.)

  3. Expert Meeting. Optimized Heating Systems Using Condensing Boilers and Baseboard Convectors

    Energy Technology Data Exchange (ETDEWEB)

    Arena, L. [Steven Winter Associates, Inc., Norwalk, CT (United States)


    On August 11, 2011, in Denver, CO, a Building America Expert Meeting was held in conjunction with the Building America Residential Energy Efficiency Technical Update Meeting, to review and discuss results and future plans for research to improve the performance of hydronic heating systems using condensing boilers and baseboard convectors. A meeting objective was to provide an opportunity for other Building America teams and industry experts to provide feedback and specific suggestions for the planned research.

  4. Expert Meeting: Optimized Heating Systems Using Condensing Boilers and Baseboard Convectors

    Energy Technology Data Exchange (ETDEWEB)

    Arena, L.


    On August 11, 2011, in Denver, CO, a Building America Expert Meeting was held in conjunction with the Building America Residential Energy Efficiency Technical Update Meeting, to review and discuss results and future plans for research to improve the performance of hydronic heating systems using condensing boilers and baseboard convectors. A meeting objective was to provide an opportunity for other Building America teams and industry experts to provide feedback and specific suggestions for the planned research.

  5. Optimization of the heat output of wall convectors with using an unconventional slumped glass cover

    Directory of Open Access Journals (Sweden)

    Kulhavy Petr


    Full Text Available This paper deals with study of a new shape of the glass cover of heat convectors. Design of the heat convectors is characterized by the low water volume, highly variable geometry, adjustable heat output and the pressure losses that arise when the fluid flow through the exchanger. Based on a new concept of a slumped glass cover of the exchanger have been created some numerical models and also carried out experiments in order to find and optimize an appropriate shape. The glass materials are very specific mainly due to their specific shaping abilities and technological capabilities of manufacturing. The aim is to determine an appropriate shape and a curvature of the glass body and also the position and size of the exchanger. It has been found a significant dependence of the heat exchanger position on to the total heat output of an entire device. Simultaneously has been proved also the dependence of a shape of the cover plate, to the total heat output, that is more considerably for natural than for the forced convection.

  6. Self-sufficient and active PCM cooling convectors. Reduction of installed capacity; Autarkie en actieve PCM-koelconvectoren. Geinstalleerd vermogen kan fors omlaag

    Energy Technology Data Exchange (ETDEWEB)

    Van Holten, P. [VSL Air-o-vent, Grimbergen (Belgium); Schmitz, H. [Verwol Klimaatplafonds, Delft (Netherlands)


    Conventional active cooling convectors are supplied with a hot water and cold water battery. In the innovative active PCM (phase change materials) cooling convectors the cold water battery is replaced by a battery of PCM plates which operate as a cooler in the summer and as a cooler and/or heater in the other seasons. [Dutch] Conventionele actieve koelconvectoren zijn normaliter voorzien van een warmwater- en een koelwaterbatterij. In de innovatieve actieve PCM-koelconvector is de koelwaterbatterij vervangen door een batterij van PCM-platen die fungeren als koeling voor de zomer en als koeling en verwarming voor de overige jaargetijden.Voor dit Iaatstgenoemde 2-pijpsklimaatsysteem komt steeds meer belangstelling.

  7. Conventional ceiling versus PCM induction convectors. Part 1. Performance criteria, calculations, physical behavior and controllability; Prestatiecriteria, berekeningen, fysisch gedrag en regelbaarheid. Deel 1. Traditionele plafond-versus PCM-inductieconvectoren

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, A.H.H. [Autarkis, Almere (Netherlands)


    Two articles compare the traditional induction convector and the innovative PCM induction convectors with each other. Part 1 addressed the traditional ceiling induction convectors and corresponding performance criteria, cooling and heat load calculation, the physical behavior of heat exchangers and the adjustability of the feed-back control loop. [Dutch] In twee artikelen worden traditionele inductieconvectoren en innovatieve PCM-inductieconvectoren met elkaar vergeleken. Dit eerste deel gaat in op traditionele plafondinductieconvectoren en de bijbehorende prestatiecriteria, koel- en warmtelastberekening, het fysische gedrag van warmtewisselaars en de regelbaarheid van de 'feed back'-regelkring.

  8. A comparative experimental and numerical study to investigate the relative merits of convectors and ``C'' inserts in cooling cold-rolled coils (United States)

    Bhattacharya, Tathagata; Chakraborty, Debadi; Singh, Vikas


    The coil cooling and storage unit (CCSU) is used to cool cold-rolled coils to the temper rolling temperature after the annealing cycle is over at the batch annealing furnace (BAF) in a cold rolling mill (CRM). In the CCSU, the coils are kept on the cooling bases for any fixed time irrespective of the grade and tonnage. Therefore, the need for a mathematical model to accurately predict the cooling time of the coils was felt. The current study involves experimental and numerical analysis of a stack of coils with respect to heat transfer and fluid flow. A comparative study was carried out to ascertain the relative merits of convectors and “C” inserts (CIs) in the cooling the coils. The air flow distribution for the case of different convectors and CIs was measured by means of a full scale physical model. Two different mathematical models were applied to model the fluid flow and flow distribution through the stack of coils. The first flow model uses the hydraulic resistance concept for estimating the air flow rate distribution, whereas the second flow model uses commercial computational fluid dynamics (CFD) software and predicts the velocity distribution in the flow path between two coils in a stack. The predictions from these two models compare well with the experimental data. The flow models were used to calculate the average heat-transfer coefficient in different flow passages in a stack. The heat-transfer coefficients thus obtained were used to tune and validate a two-dimensional transient heat-transfer model of coils. The heat-transfer model predicts the cooling time of coils accurately and also suggests a possible reduction of cooling time if CIs are used in place of convectors.

  9. Active cooling convectors in the ''Altstadt-Palais'' building. Feng Shui criteria and users' wishes were considered; Aktive Kuehlkonvektoren im Altstadt-Palais. Feng Shui-Kriterien und Nutzerwuensche beruecksichtigen

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, Wolfgang


    Modern air conditioning systems are not chosen for technical and economic aspects alone, but there are various boundary conditions that are generally considered. In the case of the Altstadt-Palais building at Karl-Scharnagl-Ring, Munich, which has an office floor space of about 9,800 m{sup 2}, also Feng Shui criteria were taken into account apart from 'normal' criteria like room flexibility, thermal comfort, and economic efficiency. The new system has cooling convectors with primary air supply that are integrated in the ceilings. (orig.)

  10. Performance measurement and evaluation of a heat pump system with wind convectors. An installation on a nursing home/medical centre in Mariefred. Maetning och utvaerdering av vaermepumpsystem med vindkonvektorer. Sjukhem/vaardcentral i Mariefred

    Energy Technology Data Exchange (ETDEWEB)

    Lagerkvist, K.O.; Larsson, R.


    The objective of this work has been primarily to ascertain the amount of thermal energy supplied, and electrical energy consumed, by the heat pump installation. Other factors that have been investigated are concerned with the characteristics of the wind convectors as heat absorbers and icing and defrosting behaviour. A total of about 1105 MWh of heat was supplied during the measured year (from June 1984 to May 1985), of which about 711 MWh came from the heat pumps, with the remaining 394 MWh from the electric immersion heaters. The immersion heaters consumed about 406 MWh, the heat pumps 296MWh and other ancillary equpiment (pumps etc) about 28 MWh. The coefficient of performance of the entire heating system was 1.5. The electric immersion heaters supplied a total of about 52 MWh of electrical energy for defrosting, of which about 43 MWh was actually used for defrosting. The capital cost of the entire heating system amounted to about SEK 2.3 million, of which SEK 1.1 million was accounted for by the heat pump plant. The annual cost saving for the heat pump system alone amounts to a total of SEK 120.000. The total annual saving for the entire heating system amounted to about SEK 25.000. (authors).

  11. Technology Assessment of Doe's 55-we Stirling Technology Demonstrator Convector (TDC) (United States)

    Furlong, Richard; Shaltens, Richard


    The Department of Energy (DOE), Germantown, Maryland and the NASA Glenn Research Center (GRC), Cleveland, Ohio are developing a Stirling Convertor for an advanced radioisotope power system as a potential power source for spacecraft on-board electric power for NASA deep space science missions. The Stirling Convertor is being evaluated as an alternative high efficiency power source to replace Radioisotope Thermoelectric Generators (RTGs). Stirling Technology Company (STC), Kennewick, Washington, is developing the highly efficient, long life 55-We free-piston Stirling Convertor known as the Technology Demonstrator Convertor (TDC) under contract to DOE. GRC provides Stirling technology expertise under a Space Act Agreement with the DOE. Lockheed Martin Astronautics (LMA), Valley Forge, Pennsylvania is the current power system integrator for the Advanced Radioisotope Power System (ARPS) Project for the DOE. JPL is responsible for the Outer Planets/Solar Probe Project for NASA.

  12. Potential of energy conservation in heating systems by means of blower convectors; Energieeinsparungspotential in Heizungsystemen durch den Einsatz von Geblaesekonvektoren

    Energy Technology Data Exchange (ETDEWEB)

    Binder, Andreas; Raisch, Ingo


    Blowers are used for heating in buildings, mostly under windows, in corners, or in niches. When heating systems are modernized, it is a useful strategy to reduce the flow temperature, but this means that the existing radiator is underdimensioned. A convective blower is presented that fits into most heating niches and provides the same capacity at lower water temperatures. Disadvantages are electric power consumption, higher noise, and faster soiling. Advantages are fast and comfortable room temperature control and the possibility of cooling. Theoretical assessments are made to investigate the potential savings resulting from convective blowers as well as their effects in terms of comfort and air quality. [German] In Gebaeuden werden zur Raumheizung in vielen Faellen Radiatoren eingesetzt. Diese werden beispielsweise unter Fenstern oder in Ecken platziert. Der Architekt sieht fuer den Einbau der Geraete oftmals eine Nische vor. Wird das komplette Heizungssystem saniert, ist es unter energetischen Gesichtspunkten sinnvoll die Vorlauftemperatur zu reduzieren. Der vorhandene Heizkoerper ist damit unterdimensioniert. Es wird ein Geblaesekonvektor entwickelt, der in eine Vielzahl der architektonisch ueblichen Heiznischen passt. Bei Abgabe der gleichen thermischen Leistung, ist es mit diesem Geraet moeglich die Heizung bei geringeren Wassertemperaturen zu betreiben. Die Beheizung von Raeumen mittels Konvektoren ist aber auch mit einigen Nachteilen behaftet, so wird elektrische Energie benoetigt, die Geraete emittieren Schall und neigen staerker zur Verschmutzung. Dem gegenueber stehen einige Vorteile wie einer schnelleren und komfortableren Regelung der Raumtemperatur und die Moeglichkeit zu Kuehlen. Es werden theoretische Abschaetzungen durchgefuehrt, wie gross das Einsparpotential durch Geblaesekonvektoren sein kann, und wie sich die Umstellung auf den Komfort, und die Luftqualitaet auswirkt.

  13. Obstacles, an Energy-Efficient Method to Reduce Downdraught from Large Glazed Surfaces

    DEFF Research Database (Denmark)

    Topp, Claus; Heiselberg, Per

    Thermal discomfort due to downdraught from glazed surfaces are often met by convectors placed close to the surface, but this may lead to increased energy consumption. The objective of this research is to investigate the effect of a horizontal obstacle on the boundary layer flow at a high cold ver...

  14. Energy-Efficient Measures to Avoid Downdraft from Large Glazed Facades

    DEFF Research Database (Denmark)

    Heiselberg, Per; Overby, H.; Bjørn, Erik

    Glazed facades may cause thermal discomfort due to downdraft. Convectors placed close to the facade can prevent downdraft but can cause an increase in the energy consumption. The objective of this research was to investigate whether the structural system of a glazed facade can be used to reduce d...

  15. Estudio del empleo de un convertidor catalítico para las emisiones gaseosas en un motor de ignición por chispa usando etanol como combustible. // Study of the employment of a catalytic convertor for the gassy emissions in an spark ignition engine using et

    Directory of Open Access Journals (Sweden)

    K. C. R. Martins


    Full Text Available Con este trabajo de investigación se estudia el índice de emisiones gaseosas en un motor de ignición por chispa movido conetanol y se analiza el control de estas emisiones con aplicación de un convertidor catalítico platino/paladio (Pt/Pd en elsistema de descarga del motor. Fueron realizados ensayos dinamométricos de un motor de combustión interna MCI paraanalizar las emisiones y el control de estas, en condiciones operacionales, en función de la rotación y ángulo de avance deignición. El convertidor catalítico alcanzó un 75% de eficiencia cuando el ángulo de avance de ignición del motor aumentópara 16o. Se observó que en rotaciones de 2000 r.p.m el convertidor catalítico presentó mayor reducción de las emisionesde hidrocarburos no quemados HC, monóxido de carbono CO y óxidos de nitrógeno NOx. Con la aplicación de unconvertidor catalítico en un vehículo se debe estandarizar nuevas regulaciones en cuanto al ángulo de avance de igniciónpara optimizar el funcionamiento del motor.Palabras claves: Convertidor catalítico; emisiones de escape; eficiencia catalítica; etanol.____________________________________________________________________________Summary.With this investigation work the index of gassy emissions is studied in an spark ignition engine using ethanol, the control ofthese emissions is analyzed with application of a platinum/palladium (Pt/Pd catalytic convector in the engine dischargesystem. Rehearsals carried out in engines in order to analyze the emissions and the control of these, under operationalconditions, in function of the rotation and angle of ignition advance were carried out. The catalytic convector reaches 75%of efficiency when the ignition advance angle of the engine increased to 16o. It was observed that in rotations of 2000r.p.m the catalytic convector presented bigger reduction of the emissions of non-burnt hydrocarbons HC, monoxide ofcarbon CO and nitrogen oxides NOx. With the application of a

  16. Optimizing Hydronic System Performance in Residential Applications

    Energy Technology Data Exchange (ETDEWEB)

    Arena, L.; Faakye, O.


    Even though new homes constructed with hydronic heat comprise only 3% of the market (US Census Bureau 2009), of the 115 million existing homes in the United States, almost 14 million of those homes (11%) are heated with steam or hot water systems according to 2009 US Census data. Therefore, improvements in hydronic system performance could result in significant energy savings in the US. When operating properly, the combination of a gas-fired condensing boiler with baseboard convectors and an indirect water heater is a viable option for high-efficiency residential space heating in cold climates. Based on previous research efforts, however, it is apparent that these types of systems are typically not designed and installed to achieve maximum efficiency. Furthermore, guidance on proper design and commissioning for heating contractors and energy consultants is hard to find and is not comprehensive. Through modeling and monitoring, CARB sought to determine the optimal combination(s) of components - pumps, high efficiency heat sources, plumbing configurations and controls - that result in the highest overall efficiency for a hydronic system when baseboard convectors are used as the heat emitter. The impact of variable-speed pumps on energy use and system performance was also investigated along with the effects of various control strategies and the introduction of thermal mass.

  17. Design and Development of a TEG Cogenerator Device Integrated into a Self-Standing Natural Combustion Gas Stove (United States)

    Codecasa, Matteo Paolo; Fanciulli, Carlo; Gaddi, Roberto; Gomez-Paz, Francisco; Passaretti, Francesca


    Heating by gas combustion, by use of different types of systems and plants, is widespread in residential and industrial environments. One example is the gas stove, the heat-radiating unit of which operates autonomously with a local gas feed and, possibly, electricity for an optional fan convector. A thermoelectric generator (TEG) can be integrated within this type of autonomous gas heater for local production of electric power, to support electrical auxiliaries, where desired, without the need for any connection to the electricity grid. This approach can lead to easier installation and operation and increases overall efficiency. A new prototype of an autonomous gas heater has been implemented by integration of a TEG device of simple and robust design, easily operated by the end user. A small amount of heat is withdrawn and converted into electricity by the TEG. This enables self-sustaining operation and, moreover, powers new ancillary functions (e.g. fan convector) without extra electrical requirements and no need for an electrical connection.

  18. Development of Direct-Use Projects: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Lund, J.


    A geothermal direct-use project utilizes a natural resource, a flow of geothermal fluid at elevated temperatures, which is capable of providing heat and/or cooling to buildings, greenhouses, aquaculture ponds, and industrial processes. Geothermal utilization requires matching the varied needs of the user and characteristics of the resource in order to development a successful project. Each application is unique; guidelines are provided for the logical steps required to implement a project. Recommended temperature and flows are suggested for spas and pools, space and district heating, greenhouse and aquaculture pond heating, and industrial applications. Guidelines are provided for selecting the necessary equipment for successfully implementing a direct-use project, including downhole pumps, piping, heat exchangers, and heat convectors. Additionally, the relationship between temperature, flow rate, and the use of heat exchangers to provide heat to a space with hot water or hot air is provided for a number of applications, with suggested 'rules of thumb'.

  19. Indoor thermal performance evaluation of Daystar solar collector (United States)

    Shih, K., Sr.


    The test procedures used and results obtained from a test program to obtain thermal performance data on a Daystar Model 21B, S/N 02210, Unit 2, liquid solar collector under simulated conditions are described. The test article is a flat plate solar collector using liquid as a heat transfer medium. The absorber plate is copper and coated with black paint. Between the tempered low iron glass and absorber plate is a polycarbonate trap used to suppress convective heat loss. The collector incorporates a convector heat dump panel to limit temperature excursions during stagnation. The following tests were conducted: (1) collector thermal efficiency; (2) collector time constant; (3) collector incident angle modifier; (4) collector heat loss coefficient; and (5) collector stagnation.

  20. Síntesis de Filtros en Modo Voltaje y Modo Corriente Usando un Dispositivo Activo Universal Synthesis of Voltage Mode and Current Mode Filters by Using a Universal Active Device

    Directory of Open Access Journals (Sweden)

    D. Torres


    Full Text Available Se presenta un método enfocado a la síntesis de filtros activos en modo voltaje y modo corriente, modelados con amplificadores operacionales de transconductancia (OTAs, y capacitores. El OTA se sintetiza usando el dispositivo activo universal conocido como convector de corriente negativo de segunda generación (CCII-. Se aprovecha el valor de la impedancia parásita del CCII- para implementar la transconductancia del amplificador operacional. Se describe el procedimiento de transformación de una topología de modo voltaje a modo corriente y viceversa, así como la síntesis de filtros usando el CCII-. Se presentan resultados de simulación usando SPICE, para demostrar la confiabilidad del procedimiento de síntesis de filtros en modo voltaje y modo corriente usando el convector de corriente negativo de segunda generaciónA method focused on the synthesis of active filters both voltage mode type and current mode type, modeled by operational transconductance amplifiers (OTAs, and capacitors, is presented. The OTA is synthesized by using the universal active device known as negative second generation current conveyor (CCII-. The value of the parasitic impedance of the CCII- is used to implement the transconductance of the OTA. the procedure of transformation of a topology from voltage mode to current mode and viceversa, as well as the synthesis of filters by using the CCII-. Simulation results are presented by using SPICE, to demonstrate the suitability of the procedure for the synthesis of filters in voltage mode type and current mode type by using the CCII-.

  1. Study and verification of the superposition method used for determining the pressure losses of the heat exchangers

    Directory of Open Access Journals (Sweden)

    Petru Michal


    Full Text Available This paper deals with study of the pressure losses of the new heat convectors product line. For all devices connected to the heating circuit of the building, it‘s required to declare a tabulated values of pressure drops. The heat exchangers are manufactured in a lot of different dimensions and atypical shapes. An individual assessment of the pressure losses for each type is very time consuming. Therefore based on the resulting data of the experiments and numerical models, an electronic database was created that can be used for calculating the total values of the pressure losses in the optionally assembled exchanger. The measurements are standardly performed by the manufacturer Licon heat hydrodynamic laboratory and the numerical models are carried out in COMSOL Multiphysics. Different variations of the convectors geometry cause non-linear process of energy losses, which is proportionately about 30% larger for the smaller exchanger than for the larger types. The results of the experiments and the numerical simulations were in a very good conjuncture. Considerable influence of the water temperature onto the total size of incurred energy losses has been proven. This is mainly caused by the different ranges of the Reynolds number depending on the viscosity of the used liquid. Concerning to the tested method of superposition, it is not possible to easily find the characteristic values appropriate for the each individual components of the heat exchanger. Every of the components behaves differently, depend on the complexity of the exchanger. However, the correction coefficient, depended on the matrix of the exchanger, that is suitable for the entire range of the developed product line has been found.

  2. Transient Analysis and Performance Prediction of Nocturnal Radiative Cooling of a Building in Owerri, Nigeria

    Directory of Open Access Journals (Sweden)

    K.N. Nwaigwe


    Full Text Available A study aimed at a Transient analysis and performance prediction of passive cooling of a building using long wave nocturnal radiation in Owerri, Nigeria are presented. The system modeled consists of the room of a building with a radiator panel attached to its roof, water storage tank located inside the room, pump to circulate water through the radiator panel at night and through a heat exchanger in the room during the day. The mathematical model is based on the thermal radiation properties of the local atmosphere, the heat exchange equations of the radiator panel with the sky during the night and the equations incorporating the relevant heat transfers within the space to be cooled during the day. The resulting equations were transformed into explicit finite difference forms for easy implementation on a personal computer in MATLAB language. This numerical model permits the evaluation of the rate of heat removal from the water storage tank through the radiator panel surface area, Qwt,out, temperature depression between the ambient and room temperatures (Tamb-Trm and total heat gained by water in the storage tank from the space to be cooled through the action of the convector during the day, Qwt,in. The resulting rate of heat removal from the radiator gave a value of 57.6 W/m2, temperature depression was predicted to within 1-1.5ºC and the rate of heat gain by the storage water was 60 W/m2. A sensitivity analysis of the system parameters to ±25% of the base case input values was carried out and the results given as a percentage variation of the above system performance parameters showed consistency to the base case results. An optimal scheme for the modeled 3.0×3.0×2.5 m3 room showed a radiator area of 18.2 m2, a convector area of 28.62 m2 and a tank volume of 1.57 m3. These results show that passive nocturnal cooling technique is a promising solution to the cooling needs for preservation of food and other agricultural produce. It is also

  3. Analyse du comportement thermique du sol d'une serre agricole par simulation dynamique (United States)

    Monteil, C.; Amouroux, M.


    The overall energetical behaviour of a greenhouse is significantly affected by diurnal storage and nocturnal release of energy inside the soil, which is the only element with high thermal capacitance. Its specific part is analysed with a pre-existing dynamic simulation model. The first part of this paper studies the effects of 4kinds of heating exchangers along each month of an entire cultivation period: hot air convector, aerial metallic pipes with hot water circulation, radiant mulch or buried pipes with warm water circulation. The second part develops the hourly behaviour of both greenhouse and soil during a cold standard-day with each of the 4exchangers. The third part is a sensibility study to various classes of factors in the case of hot air convector exchanger: climatic environment, control policy, intrinsic properties of the greenhouse (soil characteristics, crop density, cover transparency). Le comportement énergétique global d'une serre agricole est influencé de manière parfois importante par le stockage diurne et la restitution nocturne d'énergie au sein de son sol, seul élément à grande capacité thermique. Le rôle spécifique joué par le sol est analysé en appliquant un modèle de simulation dynamique déjà existant. Une première partie compare les effets de 4types d'échangeurs de chauffage sur chaque mois d'une période de culture : aérotherme, tubes aériens à circulation d'eau chaude, paillage radiant ou tubes enterrés à circulation d'eau tiède. Une seconde partie développe le comportement horaire de la serre et du sol pour une journée-type froide en présence de chacun des échangeurs. Une troisième partie précise la sensibilité du bilan thermique de la serre et du sol à différents types de facteurs dans le cas d'un échangeur par aérotherme: environnement climatique, politique de contrôle de la serre, propriétés intrinsèques de la serre (caractéristiques du sol, densité de culture, transparence de la couverture).

  4. Constructing identities in the media: newspaper coverage analysis of a major UK Clostridium difficile outbreak. (United States)

    Burnett, Emma; Johnston, Bridget; Corlett, Joanne; Kearney, Nora


    To examine how a major Clostridium difficile outbreak in the UK was represented in the media. Clostridium difficile is a serious health care-associated infection with significant global prevalence. As major outbreaks have continued to occur worldwide over the last few decades, it has also resulted in increasing media coverage. Newspaper journalists are, however, frequently criticized for sensationalized and inaccurate reporting and alarming the public. Despite such criticisms, nothing is known about how the media frame Clostridium difficile related coverage. Qualitative interpretive descriptive study. An interpretive analysis of newspaper articles from the national press that reported about the outbreak from the first day of coverage over 3 weeks (12 June-3 July 2008). Twenty-eight newspaper articles were included in the study from tabloids, broadsheets, a regional and a Sunday newspaper. Monster and war metaphors were frequently adopted to portray the severity of Clostridium difficile and the impact it can have on patient safety. In addition, the positioning of the affected patients, their families, healthcare professionals and the Government produced representations of victims, villains and heroes. This subsequently evoked notions of vulnerability, blame and conflict. The media are and will remain critical convectors of public information and, as such, are hugely influential in risk perceptions and responses. Rather than simply dismissing media coverage, further understanding around how such stories in specific contexts are constructed and represented is needed so that it can help inform future communication and management strategies. © 2013 John Wiley & Sons Ltd.

  5. Integrated energy renovation of multi-sterey buildings. Pre-design; Integreret energirenovering af etagebolig. Skitseprojekt

    Energy Technology Data Exchange (ETDEWEB)



    In the present project a predesign for an energy efficient renovation of a multi storey housing in the city of Vejle has been developed. The project is based on the experiences from IEA Task 20 'Solar Energy in Building Renovation' and has been coordinated with the ongoing work of Task 20 regarding the development of new and improved concepts for the use of solar energy in building renovation. The key goals of the energy conscious design, which was developed through an integrated design process, are: Implementation of newly developed flexible facade concept, improved thermal comfort and air quality conditions, substantial energy savings, facade integration of solar energy components and design development through an integrated process. The main energy elements are: Usage optimised energy efficient glazed balconies, unventilated solar mass wall with transparent insulation, ventilated solar walls, convector integrated fresh air in-lets and demand controlled moisture regulated ventilation. Besides the energy related aspects, the project has focussed on logistical aspects of ecology and modular mass production. Therefore, also Life Cycle Cost analyses have been an important tool in the design phase. The energy demand for heating and ventilation is expected to be reduced by 50% compared to a standard renovation. The renovation has been implemented during 2000 and it is expected to be finished in the middle of 2002. (BA)


    Directory of Open Access Journals (Sweden)



    Full Text Available ABSTRACT Almost all of the production of peanut in Indonesia is locally consumed. The peanuts are consumed in various ways, mostly through direct consumption such as boiled peanut, fried peanut, roasted peanut, peanut convectors and peanut butter.Peanut Butter is by far the most important product made from peanuts. It is the pasta forming food that is usually consumed with bread. Peanut Butter is the most popular as a high and medium class food and almost found it at the restaurant and supermarket in Indonesia. However, to process peanut butter is not so difficult for everybody who wants to do it. Peanut Butter processing is very simple with the equipment and ways properly such as to prepare good quality peanuts, sorted, drying, testa separated, grounding and boiling with mixing sugar and salt. Peanut butter has a high calorie with a good nutrition such as protein, fat, vitamins and trace element like calcium, zinc and magnesium. Reformulation and process improvement of Peanut Butter had been done at Department of agricultural products technology, Udayana University and had been disseminated to the housewife’s group and farmer’s group in Negari Village. Through the technology transfer of the Peanut Butter processing, we hope will be achieved a good quality and many several of peanuts processing in the future.

  7. Numerical Study for the Prediction of the Thermal Comfort in a Rectangular Enclosure Simulated as an Ondol Cavity with the Ondol Heating System

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Yong Il [Department of Building Equipment Engineering, Shin Heung Junior College, Eui-Jungbu (Korea, Republic of); Kwon, Sun Sok [Department of Mechanical Engineering, College of Engineering, Dong-A University, Pusan (Korea, Republic of)


    The Ondol heating system used for winter is changed from a hypocaust with floor indirectly heated by hot flue gas to that with floor heated by hot water. Residents using the Ondol heating system usually do not use a bedstead and has a sedentary life. Therefore, a perimeter zone near window is not equipped with a convector or a radiator. The activity space of residential occupants is usually over 1.5m from the floor so that the prediction of the thermal comfort in this space is required. In this study, the bottom floor surface is heated by hot water and the window is cooled by the cold outdoor air, both being assumed at uniform temperatures. The values of PMV and PPD proposed by Fanger are calculated for predicting the thermal comfort in the Ondol cavity. It is investigated that the radiant heat transfer affects to convection heat transfer in the Ondol cavity with transparent air for radiation. (author). 11 refs., 10 figs.

  8. Ergonomic design of crane cabins: a case study from a steel plant in India. (United States)

    Ray, Pradip Kumar; Tewari, V K


    The study, carried out at the Batch Annealing Furnace (BAF) shop of Cold Rolling Mill (CRM) at an integrated steel plant of India, concerns ergonomic evaluation and redesign of a manually-operated Electrical Overhead Travelling (EOT) crane cabin. The crane cabin is a complex worksystem consisting of the crane operator and twelve specific machine components embedded in a closed workspace. A crane operator has to perform various activities, such as loading and unloading of coils, setting and removal of convector plates, and routine maintenance work. Initially, an operator had to work in standing posture with bent back most of the time. Ergonomically poor design of the chair and the controls, awkward work postures, and insufficient vision angle resulting in musculoskeletal disorders (MSDs) are some of the critical problems observed.. The study, conceived as an industry-academia joint initiative, was undertaken by a design team, the members of which were drawn from both the company concerned and the institute. With the project executed successfully, a number of lessons, such as how to minimize the anthropometric mismatch, how to improve the layout of the components and controls within enclosed workspace, and how to improve work posture minimizing risk of MSDs have been learned.

  9. Numerical research of dynamic characteristics in tower solar cavity receiver based on step-change radiation flux (United States)

    Chen, Zhengwei; Wang, Yueshe; Hao, Yun; Wang, Qizhi


    The solar cavity receiver is an important light-energy to thermal-energy convector in the tower solar thermal power plant system. The heat flux in the inner surface of the cavity will show the characteristics of non-continuous step change especially in non-normal and transient weather conditions, which may result in a continuous dynamic variation of the characteristic parameters. Therefore, the research of dynamic characteristics of the receiver plays a very important role in the operation and the control safely in solar cavity receiver system. In this paper, based on the non-continuous step change of radiation flux, a non-linear dynamic model is put forward to obtain the effects of the non-continuous step change radiation flux and step change feed water flow on the receiver performance by sequential modular approach. The subject investigated in our study is a 1MW solar power station constructed in Yanqing County, Beijing. This study has obtained the dynamic responses of the characteristic parameters in the cavity receiver, such as drum pressure, drum water level, main steam flow and main steam enthalpy under step change radiation flux. And the influence law of step-change feed water flow to the dynamic characteristics in the receiver also has been analyzed. The results have a reference value for the safe operation and the control in solar cavity receiver system.

  10. The New Breakthrough in Technical Standards for HVDC Transmission Equipments

    Institute of Scientific and Technical Information of China (English)


    Project Name:12 Standards including GB/T 20838-2007 Technical Parameters and Requirements for HVDC Oil Immersed Convector Transformer Main Participant Units:Economic Research Institute,Xi'an High Voltage Apparatus Research Institute Co.Ltd.,Shenyang Transformer Academy,Xi'an Power Electronics Research Institute,China Electric Power Research Institute,TBEA Shenyang Transformer Group Corporation,China Southern Power Grid Technology Research Center Main Contributors:Fang Xiaoyan,Gou Ruifeng,Zhang Zhonguo,Yu Hongqi,Wang Mingxin,Mi Chuanlong,Wang Jian,Rao Hong,Guo Liping,Liu Jing Award Grade:First Prize Backg round High Voltage Direct Current Transmission (HVDC) is an important means to address issues of high voltage,high power,long distance and asynchronous grid-connection,and has been listed in the national mid-term and long-term science and technology development plan.The world-famous Three Gorges Project (TGP) was designed to use HVDC technology in two-thirds of electric power transmission according to the TGP plan.So it is of significance to develop HVDC in China for improvement of transmission capacity and quality.

  11. Systems for heat and cold from the ground. Proposal for a development program; System foer vaerme och kyla ur mark - Foerslag till utvecklingsprogram

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, Bengt; Gabrielsson, Anna; Fallsvik, Jan; Nilsson, Gunnel [Swedish Geotechnical Inst., Linkoeping (Sweden); Hellstroem, Goeran [Lund Inst. of Technology (Sweden). Dept. of Mathematical Physics


    Ground heat systems usually consist of a heat pump, with an evaporator connected to a heat carrier circuit of heat exchangers in the ground, and a condenser connected to the heat distribution system inside the building (radiators, fan convectors, floor heating etc). The heat pump's compressor is connected to the electricity grid. Similar systems without heat pumps are also used, where the excess heat from the building or process is exchanged with the cooler ground solely by circulation of the heat carrier fluid in the ground heat exchangers, so called 'Tree cooling'. The performance of ground heat systems depends on several factors. There is a continuous development of components and their interaction in heating/cooling systems, both in Sweden and abroad. Based on the current state of the art of ground heat systems and the national energy market it is possible to identify the development potential within many areas. In this report the development potentials for ground heat systems are presented in the following program areas: Combined heating/cooling systems with or without heat pumps and improvements of existing systems. Horizontal, compact and vertical ground heat exchangers, installation methods. Geological prerequisites and geotechnical impact of heating and/or cooling. Thermal capacity of all types of ground heat exchangers including moisture transport effects. Design specifications for different types of ground heat exchangers and ground conditions. Operation and maintenance. Environmental impact, e.g. of heat carrier fluids and local government environmental protection requirements. Economic optimization based on verified technical performance and cost figures.

  12. Mitigation benefits of forestation greatly varies on short spatial scale (United States)

    Yakir, Dan; Rotenberg, Eyal; Rohatin, Shani; Ramati, Efrat; Asaf, David; Dicken, Uri


    Mitigation of global warming by forestation is controversial because of its linkage to increasing surface energy load and associated surface warming. Such tradeoffs between cooling associated with carbon sequestration and warming associated with radiative effects have been considered predominantly on large spatial scales, indicating benefits of forestation mainly in the tropics but not in the boreal regions. Using mobile laboratory for measuring CO2, water and energy flux in forest and non-forest ecosystem along the climatic gradient in Israel over three years, we show that the balance between cooling and warming effects of forestation can be transformed across small spatial scale. While converting shrubland to pine forest in a semi-arid site (280 mm annual precipitations) requires several decades of carbon sequestration to balance the radiative warming effects, similar land use change under moist Mediterranean conditions (780 mm annual precipitation) just ~200 km away showed reversal of this balance. Specifically, the results indicated that in the study region (semi-arid to humid Mediterranean), net absorb radiation in pine forests is always larger than in open space ecosystems, resulting in surface warming effects (the so-called albedo effect). Similarly, depression of thermal radiation emission, mainly due canopy skin surface cooling associated with the 'convector effect' in forests compared with shrubland ecosystems also appears in all sites. But both effects decrease by about 1/2 in going from the semi-arid to the humid Mediterranean sites, while enhanced productivity of forest compared to grassland increase about fourfold. The results indicate a greater potential for forestation as climate change mitigation strategy than previously assumed.

  13. Numerical Research on Dynamic Characteristics in Solar Cavity Receiver Based on Step-Change Radiation Flux%瞬态阶跃热流密度下腔式吸热器动态特性研究

    Institute of Scientific and Technical Information of China (English)

    陈政伟; 王跃社; 陈开拓; 王启志; 李迪


    The solar cavity receiver is an important light-energy to thermal-energy convector in the tower solar thermal power plant system. The heat flux of the inner surface in the receiver will present the characteristics of non-continuous change especially in non-normal and transient weather conditions, which may result in a continuous dynamic variation of the characteristic parameters. Therefore it will seriously affect the stability and safe operation of the receiver. In this paper, on the basis of the non-continuous step change of the radiation flux, we established a non-linear dynamic model by sequential modular approach, which gives a comprehensive consideration of flash or condensation in the two-phase flow. This study has obtained the dynamic responses of the characteristic parameters under step change radiation flux. The results can provide scientific guidance to the safe operation and control of the cavity receiver system.%腔式吸热器是塔式太阳能热发电系统光热转换的关键部件,云层遮挡等非正常瞬态气象条件会引起腔体内热流密度呈现出瞬态阶跃扰动的非连续性特点,易造成腔式吸热器状态参数有较大的动态扰动,严重影响了吸热器的稳定和安全运行。本文基于辐照强度阶跃变化的非连续性特点,综合考虑了压力变动时两相流中的闪蒸和闪凝现象,采用序贯模块法构建了腔式吸热器的动态特性非线性数学模型,获得了辐照强度阶跃扰动时腔式吸热器各耦合输出参数的动态响应规律。这些规律对于腔式吸热器的热力系统及控制系统的设计具有重要的指导意义。