Energy Technology Data Exchange (ETDEWEB)

The present invention is a device for a solar heating system having a solar collector, a storage tank connected to the solar collector, a pump for circulating liquid from the tank to the solar collector, a supply of liquid at a temperature above freezing and a connection from the supply of liquid to the solar collector for replacing any liquid lost from said solar collector. The device comprises a sensor for sensing the temperature of liquid in the solar collector, and a valve for bleeding liquid from the solar collector when the sensed temperature falls below a predetermined minimum whereby cool liquid in the solar collector is automatically replaced by liquid at a temperature above freezing.

Energy Technology Data Exchange (ETDEWEB)

A solar thermal powered aircraft powered by heat energy from the sun. A heat engine, such as a Stirling engine, is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller. The heat engine has a thermal battery in thermal contact with it so that heat is supplied from the thermal battery. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor ...

Energy Technology Data Exchange (ETDEWEB)

One of the main disadvantages of solar air collectors in practical applications is their relatively low efficiency. In this experimental investigation, the shape and arrangement of absorber surfaces of the collectors were reorganized to provide better heat transfer surfaces suitable for the passive heat transfer augmentation techniques. The performance of such solar air collectors with staggered absorber sheets was tested. The experimental results show that it is possible to provide 10 to 25% enhancement in the efficiency compared to the conventional solar air collectors. (authors)

Energy Technology Data Exchange (ETDEWEB)

A set of nomographs is presented which can be used to estimate the average annual solar fraction for solar space and water heating at a large number of DOD facilities. The solar fraction estimated from the nomograph is in close agreement with F-Chart 3.0 and allows for variation of the following parameters: annual load, collector area, collector transmittance-absorptance coefficient, and collector overall loss coefficient.

Energy Technology Data Exchange (ETDEWEB)

A solar thermal powered aircraft powered by heat energy from the sun. A Rankine-Brayton hybrid cycle heat engine is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller or other mechanism for enabling sustained free flight. The Rankine-Brayton engine has a thermal battery, preferably containing a lithium-hydride and lithium mixture, operably connected to it so that heat is supplied from the thermal battery to a working fluid. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A ...

Energy Technology Data Exchange (ETDEWEB)

This research report for the Swiss Federal Office of Energy (SFOE) presents the results of a project that examined the feasibility of setting up 'MINERGIE' low-energy-consumption module standards for the production of heat in small residential buildings. The aims of the standards and the basic idea behind the MINERGIE-modules are discussed. The concepts of the modules for heat pumps and wood-fired heating systems and their combination with solar installations are examined, as are their areas of application. The requirements placed on the modules are listed. System concepts, including simple schematics for typical installations, are presented for wood-log, wood-chippings and pellets-fired systems as well as for ground-loop and air-water heat pump systems as well as their solar-aided counterparts. The results of cost-benefit analyses are ...

Energy Technology Data Exchange (ETDEWEB)

This book comprises an up-to-date description of the astrophysical characteristics of the sun, including modern techniques used in solar research. Provides an historical background of solar research and techniques and covers the necessary astrophysics for solar studies, energy generation in the interior, the convection zone, the non- thermally heated layers, and solar wind are described in detail. Also considers the sun in relation to other stars, including information on its variable outputs of light, charged particles, and fields.

Energy Technology Data Exchange (ETDEWEB)

A conceptual design of a solar retrofit to US Gypsum's plant at Sweetwater, Texas, has been developed which provides heated air to a large gypsum board drying kiln that is currently under construction. The solar heated air displaces natural gas normally used for the process heat. The solar retrofit is composed of a tower focus collector with a cavity receiver which uses air as the heat transfer fluid. An executive summary of the conceptual design, system performance, economics, and development plan is presented. (WHK)

Energy Technology Data Exchange (ETDEWEB)

A solar energy desalination process utilizing solar radiation directly for the evaporation of salt water is described. Ambient air takes on water vapor as the air passes through an evaporative medium. It is then directed between a saline water-covered, solar absorbing surface and a solar collecting housing. The resulting heated and moisture-saturated air is cooled in a heat exchange means where condensation of fresh water occurs. Simultaneously, cool salt water is utilized as the cooling water in the heat exchange means, and takes on the heat of condensation given up by the condensing vapor. The heated salt water from the heat exchange means is partially directed over the solar absorbing surface, and at least a portion of it is also directed to wet the ...

Energy Technology Data Exchange (ETDEWEB)

The mainly nonstationary operation of a solar-heated receiver can be simulated with sufficient accuracy only if data about the dynamic behavior are available. For this reason, the dynamic behavior of a solar cavity receiver with parabolic dish collector is investigated. The development of a mathematical simulation considering heat transfer and storage processes is presented and the procedure for a numerical solution is illustrated. The performance of the calculation method is finally demonstrated by simulating the passage of a cloud.

Energy Technology Data Exchange (ETDEWEB)

Stochastic models for the simulation of global radiation are discussed. Thermal transients in the ground are analyzed. The performance of buried-pipe storage and a space heating system with long-term storage is described.

International Nuclear Information System (INIS)

The article describes the energy in Lebanon. In 1995, 97% of the imported energy was based on hydrocarbons. Fuel and gas oil present 66% of the final energy. Air pollution is mainly caused by the transportation sector (vehicles and buses...) which presents 70% of the global atmospheric pollution. Renewable energy such as biomass, fossil energy, hydro-energy, solar energy... are also described. The solar energy was defined as a best solution that preserve health in Lebanon. The different applications of the solar for energy production is discussed: photovoltaic , thermal heating, sanitary hot water, electrical heaters, solar water heaters...In conclusion, solar heaters economize 80% of the annual energy expenses

Energy Technology Data Exchange (ETDEWEB)

This study reported on the performance of a passive solar radiant floor heating system designed for standard energy-saving farmhouses in northeast China. Weather data in the region was analyzed in terms of solar radiation, temperature, humidity and light levels. The heating characteristics of the building materials such as windows, doors, walls and roofs were also analyzed along with the indoor thermal environment of the farmhouse. The heating load was then calculated along with the size of the thermal storage element and the area of the collector element. The passive solar radiant floor heating system was designed for heating during the winter and cooling in summer. According to the results, the heating characteristics of the system have the potential to improve farming villages environment and the ...

Energy Technology Data Exchange (ETDEWEB)

Solar heating of gas turbine plants steps back more and more into the focus of current research. The mainly instationary operation of solar turbine power plants can only be predicted with sufficient accuracy if the transient behaviour of the receiver for the solar radiation is known. Therefore the transient behaviour of cavity receivers of different design is investigated. The mathematical model used for the simulation of the heat transfer and energy storage processes is illustrated. Computed results for receivers with various inner lining are compared and evaluated concerning their use in practice.

Energy Technology Data Exchange (ETDEWEB)

Fins serve as heat transfer augmentation features in solar air heaters; however, they increase pressure drop in flow channels. Pin fins are relatively good heat transfer augmentation features with superior aerodynamic performance, and as a result find application in some solar air heaters. The exergy optimization method is employed in sizing the pin fin. Results indicate that high efficiency of the optimized fin improves the heat absorption and dissipation potential of a solar air heater. With optimum fin efficiency and superior absorptive coating quality, useful energy losses can be minimized. Some important observations pertinent in design are made. (author)

Science.gov (United States)

Two types of evacuated tube solar collectors have been operated in space heating, cooling and domestic hot water heating systems in Colorado State University Solar House I. An experimental collector from Corning Glass Works supplied heat to the system from January 1977 through February 1978, and an experimental collector from Philips Research Laboratory, Aachen, which is currently in use, has been operating since August 1978. A flat absorber plate inside a single-walled glass tube is used in the Corning design, whereas heat is conducted through a single glass wall to an external heat exchanger plate in the Philips collector. In comparison with conventional flat-plate collectors, both types show reduced heat losses and improved efficiency. For space heating and hot water supply in winter, the ...

Energy Technology Data Exchange (ETDEWEB)

The staff of the Southwest Technology Development Institute (SWTDI), in conjunction with the staff of Industrial Solar Technology (IST), have analyzed the performance, operation, and maintenance of a large solar process heat system in use at the 5,000 inmate California Correctional Institution (CCI) in Tehachapi, CA. This report summarizes the key design features of the solar plant, its construction and maintenance histories through the end of 1991, and the performance data collected at the plant by a dedicated on-site data acquisition system (DAS).

Energy Technology Data Exchange (ETDEWEB)

The purpose of this solar energy project was to design, manufacture, install, maintain and evaluate solar heating systems in order to stimulate community acceptance of the practicality of solar applications, reduce non-renewable energy resource consumption, and decrease residential expenditures for energy. The project also provided skill training and experience for CETA employees in the design, manufacture, and installation of solar energy equipment systems. CDC's contract had four separate solar energy projects; namely: Domestic Water Heating Systems for four Single-Family Homes; Domestic Water Heating for an industrial building; Domestic Water Heating for a (4) unit apartment complex (includes (12) supplemental space heating units); and Integral Passive Water Heaters ...

Energy Technology Data Exchange (ETDEWEB)

Performance predictions have been made for attached-sunspace types of passively solar heated buildings. The predictions are based on hour-by-hour computer simulations using computer models developed in the framework of PASOLE, the Los Alamos Scientific Laboratory (LASL) passive solar energy simulation program. The models have been validated by detailed comparison with actual hourly temperature measurements taken in attached-sunspace test rooms at LASL.

British Library Electronic Table of Contents (United Kingdom)

Solar cavity receiver plays a dominant role in the light-heat conversion. Its performance can directly affect the efficiency of the whole power generation system. A combined calculation method for evaluating the thermal performance of the solar cavity receiver is raised in this paper. This method couples the Monte-Carlo method, the correlations of the flow boiling heat transfer, and the calculation of air flow field. And this method can ultimately figure out the surface heat flux inside the cavity, the wall temperature of the boiling tubes, and the heat loss of the solar receiver with an iterative solution. With this method, the thermal performance of a solar cavity receiver, a saturated steam receiver, is simulated under different wind environments. The highest wall temperature of the boi...

Energy Technology Data Exchange (ETDEWEB)

An improved hybrid solar/combustion powered receiver of the type having an insulated housing with a front end and a rear end, a heat exchanger positioned adjacent the rear housing end for extracting heat energy out of the receiver, the insulated housing surrounding the heat exchanger and forming a receiver cavity, the housing also including an aperature having an aperture axis, the aperture located in the front housing end for admitting solar radiation to the cavity to impinge upon the heat exchanger, and a plurality of gas burners to provide combustion gases within the receiver.

Energy Technology Data Exchange (ETDEWEB)

Forms used in conducting a national survey about solar energy are presented. Forms for representatives from the domestic, commercial, and industrial sectors, owners and non-owners of solar equipment, are shown. Participants were to be contacted by telephone, mail, and personal visits. (MCW)

Energy Technology Data Exchange (ETDEWEB)

The main objective of the present study is twofold: (i) to analyze thermal loads of the geothermally and passively heated solar greenhouses; and (ii) to investigate wind energy utilization in greenhouse heating which is modeled as a hybrid solar assisted geothermal heat pump and a small wind turbine system which is separately installed in the Solar Energy Institute of Ege University, Izmir, Turkey. The study shows 3.13% of the total yearly electricity energy consumption of the modeled system (3568 kWh) or 12.53% of the total yearly electricity energy consumptions of secondary water pumping, brine pumping, and fan coil (892 kWh) can be met by using small wind turbine system (SWTS) theoretically. According to this result, modeled passive solar pre heating technique and combined with geothermal heat ...

Energy Technology Data Exchange (ETDEWEB)

A numerical investigation of a humidification dehumidification desalination (HDD) process using solar energy is presented. The HDD system consists mainly of a concentrating solar water heating collector, flat plate solar air heating collector, humidifying tower and dehumidifying exchanger. Two separate circulating loops constitute the HDD system, the first for heating the feed water and the second for heating air. A mathematical model is developed, simulating the HDD system, to study the influence of the different system configurations, weather and operating conditions on the system productivity. The model validity is examined by comparing the theoretical and experimental results of the same authors. It is found that the results of the developed mathematical model are in good agreement with the experimental results and other published works. ...

Energy Technology Data Exchange (ETDEWEB)

The authors investigate the optimisation of solar-heated cavity receivers in which solar energy collected by a paraboloid collector is converted into electrical energy. The focussed solar energy enters the receiver through an aperture to heat the working fluid, which flows inside the receiver tubes and is compressed by the compressor of a gas turbine system, to the highest process temperature. A method of calculating the distribution on the inner receiver surfaces of the solar radiation reflected by the paraboloid collector is presented to begin with. The interchange of radiant energy inside the receiver cavity can be calculated on this basis, including the radiation loads, the temperatures of the inner receiver walls, and the radiative and convective losses. The temperature fields in the tube walls must be known for determining the strength required of receiver tubes; they can be ...

International Nuclear Information System (INIS)

Solar drier does not degrade any more the dried products with the manner of the products dried at the natural sun. The drying unit is composed mainly of a solar air collector and an enclosure of drying. The transformation of the solar radiation into heat is done thanks to the solar collector whose effectiveness is increased by the addition of suitable baffles in the mobile air vein. The efficiency of the collector reaches then 80. The hot air on the outlet side of the collector arrives in the enclosure of drying where the heat transfer with the product to be dried is done by convection. The kinetics drying study shows that in addition to the dependence of the temperature and air velocity of drying, the speed of drying also depends on fragmentation on the product to dry, and mainly, of the product surface in contact with the drying air. Thus, the hygrometry is ...

British Library Electronic Table of Contents (United Kingdom)

This study addresses the solar thermal decomposition of natural gas for the co-production of hydrogen, as well as Carbon Black as a high-value nano-material, with the bonus of zero CO2 emissions. The work focused on the development of a medium-scale solar reactor (10kW) based on the concept of indirect heating. The solar reactor is composed of a cubic cavity receiver (20cm side), which absorbs concentrated solar irradiation through a quartz window via a 9cm-diameter aperture. The reacting gas flows inside four graphite tubular reaction zones that are settled vertically inside the cavity. Experimental results were as follows: methane conversion and hydrogen yield of up to 98% and 90%, respectively, were achieved at 1770K, and acetylene was the most important by-product, with a mole fraction...

International Nuclear Information System (INIS)

Ground-source heat pump systems (GSHPSs), also referred to as geothermal heat pump systems (GHPSs), have been widely used in residential and commercial buildings for years due to their outstanding energy utilization efficiencies. In this study, an energy and exergy modeling of solar assisted ground-source heat pump systems for residential applications is presented for system analysis and performance evaluation. In this regard, the performance of a solar assisted ground-source heat pump heating system, installed in Solar Energy Institute of Ege University, Izmir, Turkey, is evaluated based on the actual operational data to show how energy and exergy efficiencies values change with the system. The average heating coefficient of performances (as energy efficiencies) of the solar ...

Energy Technology Data Exchange (ETDEWEB)

The solar thermal production of zinc is considered for the conversion of solar energy into storable and transportable chemical fuels. The ultimate objective is to develop a technically and economically viable technology that can produce solar zinc. The program strategy for achieving such a goal involves research on two paths: a direct path via the solar thermal splitting of ZnO in the absence of fossil fuels, and an indirect path via the solar carbothermal/CH{sub 4}-thermal reduction of Zn O, with fossil fuels (coke or natural gas) as chemical reducing agents. Both paths make use of concentrated solar energy for high-temperature process heat. The direct path brings us to the complete substitution of fossil fuels with solar fuels for a sustainable energy supply system. The indirect path creates a link between today`s ...

Energy Technology Data Exchange (ETDEWEB)

In the course of this year six local exchange offices with alternative heating and hot water plants were started up in Switzerland. They are all of the same building type, designed for not more than 1000 telephone subscribers and for the same architectural conditions. However, the buildings are situated in different areas of the country and are thus subject to different environmental conditions. Solar collectors supplemented by electricity boilers are fitted to two of these objects. Heat pumps are operated in two other exchange offices while the last two are equipped with electric heating devices. For purposes of comparison two new test plants of the same size with oil heating devices are set up.

Energy Technology Data Exchange (ETDEWEB)

Solar energy can be economically converted into electrical energy for small and medium power outputs. A typical solar power plant consists of a parabolic dish, cavity receiver and gas turbine. To obtain high gas turbine efficiences, the working fluid used has to be heated to high temperatures. This necessitates the use of expensive high-quality materials for the tubes in the receiver. This expense must be kept to a minimum. The present paper demonstrates how this aim can be achieved by meeting the so-called Bammert Criterion.

Energy Technology Data Exchange (ETDEWEB)

The failure of receivers has been one of the main operating problems at the White Cliffs solar thermal power plant. This Technical Note reports the results of an initial investigation that identifies the cause as having been their thermal fatiguing of the tube walls. The fatigue appears to be caused by unstable heat transfer at vapor qualities below the point where critical heat flux is generally exceeded. Methods for avoiding this problem are tested.

Energy Technology Data Exchange (ETDEWEB)

This report uses experimental data to compare the performance of two sodium cooled solar central receivers operated at the International Energy Agency Small Solar Power Systems project near Almeria, Spain. Performance includes point-in-time steady state efficiency, average efficiency, start-up time, and operation time. Point-in-time steady state efficiency calculations were based on the statistical method of least squares using receiver incident and absorbed powers. One receiver, a cavity type, showed a peak steady state receiver efficiency of 87% +- 5% and an average efficiency of about 67%. The other receiver, an external ''billboard'' type, had a peak steady state receiver efficiency of 96% +- 4% and an average efficiency of about 79%. The original design peak steady state efficiency predictions for both receivers were within the experimentally determined 95% probability interval. Thermal loss test data ...

Energy Technology Data Exchange (ETDEWEB)

The school building complex Waterland in The Hague, Netherlands, was built with a hybrid ventilation system. The indoor environment and energy consumption were monitored for one year. Air quality and thermal comfort are of a high quality and the consumption of energy for heating is circa 35% lower than normal. The Waterland project was one of eight demonstration projects, carried out within the framework of the ECBS-Annex 35: Hybrid ventilation in New and retrofitted Office Buildings. ECBS stands for the IEA-program Energy Conservation in Buildings and Community Systems. [Dutch] In ECBCs-annex 35 (ECBS staat voor het IEA-programma Energy Conservation in Buildings and Community Systems) is uitgebreid onderzoek gedaan naar hybride ventilatiesystemen in kantoren en scholen. Dit project heeft geleid tot acht internationale voorbeeldprojecten, waarvan scholencomplex Waterland te Den Haag er een van is. Het scholencomplex is in ...

Energy Technology Data Exchange (ETDEWEB)

Simple correlations and corresponding nomographs are presented, which express the maximum useful heat received from salt-gradient solar ponds throughout the year or during a specified season of the year, and the corresponding optimum depth of the nonconvective zone in terms of the thickness of the upper convective zone and the temperature under which the maximum useful heat is received. The correlations are valid for the Athens (Greece) area or for regions with a similar climate, because solar radiation and ambient temperature values for Athens have been employed, obtained by a statistical process of hourly measurements over a period of about 20 years. For other climates, it is easy to develop similar correlations using the same methodology, Development of the proposed correlations is based on a method, which simulates the transient operation of the salt-gradient pond using finite-differences, and ...

Energy Technology Data Exchange (ETDEWEB)

A steady-state mathematical model was developed for a bare collector. Results obtained by previous authors for heat transfer and friction in rectangular ducts with periodic disturbances were employed to evaluate the effect of such disturbances on bare collector efficiency and on its pressure drop. An effective efficiency, which takes into account extra heat obtained and additional mechanical (electric) energy consumption for moving air when heat-transfer augmentation devices are employed, was defined. Simulation results are given for a bare collector, with and without perturbations, showing efficiency and effective efficiency dependence on collector dimensions, solar radiation intensity, disturbance diameter and pitch for collector performance optimization. (author).

International Nuclear Information System (INIS)

A numerical and experimental investigation is carried out in a solar thermochemical reactor for the thermal dissociation of ZnO at 2000 K using concentrated solar energy. The reactor consists of a cavity-receiver lined with ZnO particles and directly exposed to high-flux irradiation. A transient heat transfer model is formulated to link the rate of radiation, convection, and conduction heat transfer to the reaction kinetics. The radiosity and Monte Carlo methods are applied to obtain the distribution of net radiative fluxes at the internal surfaces of the reactor cavity and at the surface of the ZnO bed. Validation is accomplished in terms of the calculated and measured transient temperature profiles and chemical reaction rates.

Energy Technology Data Exchange (ETDEWEB)

This article proposes a model for estimating the effect of the overall thermal resistance of the absorber and the coolant on a solar thermal energy system utilizing advanced heat transfer mediums. Two equations can be used to model a dynamic system: one for the maximum conversion efficiency and one to specify the constraint that, in quasi-steady state, the net energy collected must be transferred to the coolant. These two equations define a constrained optimization problem in two variables, the fluid and the absorber temperatures. The results present interesting implications for liquid metal, direct absorption, and solar evaporating systems.

British Library Electronic Table of Contents (United Kingdom)

A 2-D model has been proposed to investigate the approximate estimation of the natural convection heat loss from modified cavity receiver of without insulation (WOI) and with insulation (WI) at the bottom of the aperture plane in our previous article. In this paper, a 3-D numerical model is presented to investigate the accurate estimation of natural convection heat loss from modified cavity receiver (WOI) of fuzzy focal solar dish concentrator. A comparison of 2-D and 3-D natural convection heat loss from a modified cavity receiver is carried out. A parametric study is carried out to develop separate Nusselt number correlations for 2-D and 3-D geometries of modified cavity receiver for estimation of convective heat loss from the receiver. The results show that the 2-D and 3-D are comparabl...

Energy Technology Data Exchange (ETDEWEB)

This volume contains the corporate author index, author index, and subject index for publications entered into the IEA Biomass Conversion Technical Information System during the year 1987. (DT)

Science.gov (United States)

Not Available

Science.gov (United States)

Thermal Cavity Receivers,". JPL. Publication. 83-97,. 1983. 5Hall, III, C.A., Glakpe, E.K., Cannon,. J.N., and. Kerslake,. T.W., "Modeling ...

Energy Technology Data Exchange (ETDEWEB)

;Contents: Energy Use; Building Fabric Performance; Ventilation and Infiltration; Passive Solar Design; Heating Systems and Controls; Hot and Cold Water Provision; and Lighting and Electrical Appliances.

Energy Technology Data Exchange (ETDEWEB)

Theoretical investigations on the phase change materials (PCMs) used as the heat storage media for box-type solar cookers have been conducted in this study. The selected PCMs are magnesium nitrate hexahydrate, stearic acid, acetamide, acetanilide and erythritol. For a two-dimensional simulation model based on the enthalpy approach, calculations have been made for the melt fraction with conduction only. Different materials such as glass, stainless steel, tin, aluminum mixed, aluminum and copper are used as the heat exchanger container materials in the numerical calculations. The large value of thermal conductivity of heat exchanger container material did not make a significant contribution on the melt fraction except for at very low thermal conductivities. Based on the theoretical results, stearic acid and acetamide are found to be good compatibility with latent heat storage system. ...

Energy Technology Data Exchange (ETDEWEB)

The paper reported the results of fiscal 1994 studies on solar energy in the New Sunshine Project. Relating to the technical development for the practical use of photovoltaic power systems, the development of manufacturing technologies for low-cost substrates and the development of element technology for manufacturing low-cost polycrystalline cells/modules were reported as the development of technology for thin substrate polycrystalline solar cells for practical use. As to the research on fabrication technology for thin film solar cells for practical use, reports were made on the research on low-cost fabrication technology for large-area modules and the technological development for qualitative improvement, etc. In respect to the technological development for super-high efficiency solar cells, reported were the technological development for super-high efficiency single crystalline silicon ...

Science.gov (United States)

The results of the second phase of the program of developing low cost contacts to silicon solar cells using copper are presented. Phase 1 yielded the development of a plated Pd-Cr-Cu contact system. This process produced cells with shunting problems when they were heated to 400 C for 5 minutes. Means of stopping the identified copper diffusion which caused the shunting were investigated. A contact heat treatment study was conducted with Pd-Ag, Ci-Ag, Pd-Cu, Cu-Cr, and Ci-Ni-Cu. Nickel is shown to be an effective diffusion barrier to copper.

Energy Technology Data Exchange (ETDEWEB)

The pathway to hydrogen generation entirely from renewable energy and material sources probably goes by a transitional period with the utilization of hybrid fossil/renewable integrated systems. Solar steam reforming of methane is set in this context, specifically suited for a country like Italy whose actual energy policy is mainly based on the imported NG, but also characterized by convenient solar radiation levels in the Southern Regions. A new solar SMR process is being developed by ENEA, using molten nitrates as solar heat carriers and storage medium at about 550 C. The potential of this process have been proved theoretically by process simulation studies. Engineering and experimental activities aimed to the development of a prototype apparatus are now in progress in ENEA's laboratories. It is remarkable that the developed technology (MS powered SMR) can find interesting ...

Energy Technology Data Exchange (ETDEWEB)

A solar energy collection and conversion system is disclosed in which a cassegrain mirror system is rotated about a diurnal axis, which axis is adjusted for seasonal variations in the incidence of the sun's rays on the earth's surface. A black body absorption cavity filled with translucent or transparent fluid material is used for direct absorption of the sun's rays. The incident solar energy is absorbed directly by the fluid medium. The fluid within the cavity may be maintained under extremely high pressures and temperatures in order to utilize this fluid as a heat storage medium. Such heat storage is facilitated by apparatus which permits a change in the volume of the reflective cavity in response to the temperature or pressure of the fluid within the cavity.

Energy Technology Data Exchange (ETDEWEB)

This final report for the Swiss Federal Office of Energy (SFOE) examines a project that aimed to define standard solutions for use in buildings built to meet Minergie low energy consumption standards. These standard solutions are to provide a way of meeting Minergie standards in an easy way and thus further the use of the standard and also assure quality at the same time. The report describes how the solutions were developed on the basis of a selection of existing Minergie buildings. For various combinations of heating systems - wood, wood/solar, heat pumps (brine-water and air-water), gas/solar and oil/solar - the appropriate U-values for various building elements are listed. The resulting Minergie forms and guides are listed.

Energy Technology Data Exchange (ETDEWEB)

The cost of transporting biogas digestate can be decreased by reducing its water content. However, the digestate emits volatile compounds during drying. This study investigated the drying behaviour and the change of digestate composition. Drying took place in a hybrid solar/waste-heat dryer that used solar energy as well as waste heat from a combined heat and power unit (CHP) and the exhaust air of a microturbine. The experiment involved the use of 60 t of liquid digestate. Climatic conditions were measured inside and outside the drying hall. Dry matter (DM) and organic dry matter (ODM) were also measured on a daily basis. In addition, the energy consumption of waste and solar heat were recorded and related to the quantity of dried feedstock. The total nitrogen, ammonium, phosphate, potassium oxide, magnesium oxide and calcium oxide in the digestate were ...

Energy Technology Data Exchange (ETDEWEB)

An exergoeconomic model of a vertical ground-source heat pump residential heating system presented in this study uses exergy and cost energy mass (EXCEM) methods. The data obtained from a ground-source heat pump (GSHP) residential heating system installed at the Solar Energy Institute, Ege University, Turkey, are utilized for calculations at different reference temperature values in the range 0-25{sup o}C. The performance of the geothermal heat pump residential heating system is evaluated to indicate how exergoeconomic parameter values change with system. We also undertake a parametric study to investigate how varying reference temperatures will affect the exergoeconomic analysis of the GSHP system. A correlation between the ratio of thermodynamic loss rate to capital cost and reference state temperature is developed. (author)

Science.gov (United States)

The largest solar heating and cooling system undertaken to date is now operating at the George A. Towns Elementary School in Atlanta, Georgia. It is expected to provide more than 60 percent of the building's heating and cooling requirements, using commercially available components and techniques. The Towns project is a United States Energy Research and Development Administration-sponsored experiment. The principal components of the solar heating and cooling system designed for the school--the solar collector array, the existing gas-fired boiler, the absorption chiller, and hot and cold water underground tanks to provide thermal storage--are described. To derive maximum benefit from the experiment, the system is fully instrumented for accurate measurement of performance. Environmental data, including insolation and ambient temperture, humidity, and wind ...

Energy Technology Data Exchange (ETDEWEB)

In this work, the thermal performance of a conventional collector is improved by inserting porous substrates at the inner walls of the collector tubes. The porous substrates improve the convective heat transfer coefficient between the tube wall and the fluid. This improvement is investigated numerically and its effects on the efficiency and the useful gain of the collector are evaluated. It is found that inserting the porous substrate may raise the collector efficiency considerably, especially at high values of the overall heat loss coefficient.

International Nuclear Information System (INIS)

This 2001 edition of the guide to UK renewable companies and equipment and service providers presents summaries of the different industry sectors covering wind power, photovoltaics, solar water heating, geothermal heat pump, hydroelectric power, marine current and wave technology, bioenergy, power generation from landfill gas, energy from waste, and cogeneration. A UK company classification listing and index is provided along with listing of UK organisations and companies and an index of advertisers.

Energy Technology Data Exchange (ETDEWEB)

Due to the high investment and operation costs incurred by dryers up to 50% of the proceeds from the cultivation of medicinal plants have to be spent on drying. This study was conducted in order to determine whether these costs can be lowered when solar energy is used. As little is known about the drying behaviour of medicinal plants even today one selected sage and camomile in order to study the influence of temperature, relative humidity, and drying air velocity on drying time and drug quality. Laboratory results were used as a basis for developing a solar hothouse dryer for medicinal plants which uses the whole roof surface as solar collectors with a batch dryer set up within the hothouse. In contrast to dryers of this type used up to now a foil green house with a gable roof was used. Installation of a central heating system helps to avoid bottlenecks, allows drying at night and increases plant flow ...

International Nuclear Information System (INIS)

Full text of publication follows: Radiation hardening and embrittlement due to high-energy neutron radiation around 623 K are the important issues on reduced-activation ferritic/martensitic (RAF/M) steels. It is expected that the improvement of radiation hardening might be one of effective ways to control the mechanical properties of RAF/M after irradiation. It has been reported that the weld joint has less hardening than the base metal from the tensile test results of TIG weldments irradiated in HFIR. This report indicated that radiation hardening can be reduced by the optimization of heat treatment condition for F82H. The purposes of this study are to establish the condition of heat treatment for minimum of radiation hardening in F82H steel using Neutron/Ion-irradiation and to examine a correlation between tensile property and micro-hardness before/after irradiation. The materials used in this study were F82H IEA ...

Science.gov (United States)

New comparative tests on two different types of solar collectors are presented in this paper. A standard glazed flat plate collector and an evacuated tube collector are installed in parallel and tested at the same working conditions; the evacuated collector is a direct flow through type with external compound parabolic concentrator (CPC) reflectors. Efficiency in steady-state and quasi-dynamic conditions is measured following the standard and it is compared with the input/output curves measured for the whole day. The first purpose of the present work is the comparison of results in steady-state and quasi-dynamic test methods both for flat plate and evacuated tube collectors. Besides this, the objective is to characterize and to compare the daily energy performance of these two types of collectors. An effective mean for describing and analyzing the daily performance is the so called input/output diagram, in which the collected solar energy is ...

British Library Electronic Table of Contents (United Kingdom)

This study addresses the solar thermal decomposition of natural gas for the co-production of hydrogen and carbon black (CB) as a high-value nano-material with the bonus of zero CO2 emission. The work focused on the development of a medium-scale solar reactor (10kW) based on the indirect heating concept. The solar reactor is composed of a cubic cavity receiver (20cm-side), which absorbs concentrated solar irradiation through a quartz window by a 9cm-diameter aperture. The reacting gas flows inside four graphite tubular reaction zones that are settled vertically inside the cavity. Experimental results in the temperature range 1740-2070K are presented: acetylene (C2H2) was the most important by-product with a mole fraction of up to about 7%, depending on the gas residence time. C2H2 content i...

Energy Technology Data Exchange (ETDEWEB)

World-wide water scarcity, especially in the developing world, indicates a pressing need to develop inexpensive, decentralized small-scale desalination technologies which use renewable resources of energy. This paper provides a comprehensive review of the state-of-the-art in one of the most promising of these technologies, solar-driven humidification-dehumidification (HDH) desalination. Previous studies have investigated many different variations on the HDH cycle. In this paper, performance parameters which enable comparison of the various versions of the HDH cycle have been defined and evaluated. To better compare these cycles, each has been represented in psychometric coordinates. The principal components of the HDH system are also reviewed and compared, including the humidifier, solar heaters, and dehumidifiers. Particular attention is given to solar air heaters, for which design data is limited; and direct air ...

Energy Technology Data Exchange (ETDEWEB)

The conceptual design, parametric analysis, cost and performance analysis, and commercial assessment of a 100-MWe line-focus solar central receiver power plant are reported. This volume contains the appendices: (a) methods of determination of molten salt heat-transfer coefficients and tube-wall temperatures, (b) inputs for STEAEC programs, (c) description of system analysis computer program, (d) receiver analysis program, and (e) heliostat production plan and design methodology. (WHK)

Energy Technology Data Exchange (ETDEWEB)

The design of a solar heated cavity receiver transferring 60 MW of thermal energy to the working medium (air) for a closed-cycle gas turbine is described. The gas turbine plant with its cycle layout is presented. Then the tubes for the receiver are designed taking into account thermal and mechanical loads. It is shown how the occurring stresses are influenced by the destribution of the locally absorbed hat flux. Calculations for an existing coal fired air heater of a closed-cycle gas turbine give a first impression of the long-term behaviour to be expected of the receiver tubes.

Energy Technology Data Exchange (ETDEWEB)

Desiccant cooling is a potentially environmentally friendly technology that can be used to condition the internal environment of buildings. Unlike conventional air conditioning systems, which rely on electrical energy to drive the cooling cycle, desiccant cooling is a heat-driven cycle. This paper follows on from an initial study by the authors, and uses real meteorological data to evaluate the potential in the United Kingdom of using solar energy to drive the desiccant cooling cycle. Through the use of parametric studies, the paper investigates the energy consumption and costs associated with desiccant cooling. (author)

Energy Technology Data Exchange (ETDEWEB)

Progress in the worldwide capability of predicting the convective energy loss from solar central receivers is reviewed. The significant advances in the past three years have been in experimental areas. Baseline measurements of the convective heat transfer from large high-temperature surfaces, e.g., a flat plate and a cubical cavity, have been completed and empirical correlations have been obtained. Theoretical modeling activities have not kept pace with the experimental advances, however. Currently, the primary theoretical emphasis is the development and testing of turbulence models suitable for buoyant flows. Three major needs have been identified: the measurement of convective energy losses from operating solar central receivers; the continued development of theoretical models in spite of the relatively slow progress to date; and the quantification of the effects of atmospheric turbulence.

Energy Technology Data Exchange (ETDEWEB)

This article reports on the UN Environment Programme's (UNEP's) work in supporting the banking and financing sector by creating clean energy finance markets in developing countries. Details are given of the shifting of cash markets to credit, financing solar home systems in India, solar thermal lending in Tunisia, the financing of hotel based solar water heating in Morocco, and the Green Village Credit initiatives in the Yunnan province of China. The importance of providing banks with information needed to gain awareness and experience of renewable energy systems is stressed. The fundamentals of a bank engagement programme, financial catalysts, structuring market oriented approaches, and linking bank lending to policy making are discussed along with the need to shift to credit enhancements to help banks set up their first loan portfolios.

Energy Technology Data Exchange (ETDEWEB)

This paper deals with conversions of solar energy efficiently into electricity and into gas laser radiation. In the first section, a review study of the possibility of a solar-electric thermophotovoltaic (TPV) device has been done. In a proposed extension of the TPV concept, a Cassagranian optical system concentrates solar radiation to heat a blackbody cavity to 2400/sup 0/K. A double-layer solar cell, GaAs and Si, forming the cylindrical surface concentric to the blackbody cavity, receives the blackbody radiation and converts it into electricity efficiently. A cell conversion efficiency of 50% or more would be possible with the TPV system. The second section explores the concept of blackbody radiation pumping of gas laser media as a step toward utilization of solar energy as a laser pumping source. To demonstrate this concept, an experiment was performed in ...

Energy Technology Data Exchange (ETDEWEB)

Provides standardized energy balance sheets expressed in a common unit of tons of oil equivalent for all OECD countries as well as the regions: OECD total, IEA, North America, Pacific, OECD Europe, EEC and Yugoslavia.

Energy Technology Data Exchange (ETDEWEB)

This thesis deals with the evaluation of Solar Grade Silicon (SoG-Si) purified by different techniques, and also the fabrication and characterization of high efficiency and advanced bifacial solar cells. In the beginning of Chapter 1, various SoG-Si production methods relevant for this work are qualitatively described. The three feedstock materials used in this work are from the Fluidized Bed Reactor (FBR) process, metallurgical feedstock-I and feedstock-II process. In metallurgical feedstock-I, the lifetime of the minority charge carriers in multicrystalline silicon (mc-Si) samples at the grain boundaries are found to be higher than the grains themselves possibly due to lower resistivities in the grain boundaries. The efficiency of the best solar cell obtained using the mc-Si metallurgical feedstock-I is 16.1%. It has been identified that the fast light induced degradation, whose magnitude is lower than that of a reference ...

Energy Technology Data Exchange (ETDEWEB)

The need to increase efficiency of volumetric receivers for use in solar power plants by reducing reradiation losses and increasing the ``volumetric effect`` has promoted the idea of a receiver with tapered ducts. These seems to be very promising since higher efficiency and considerable saving of material can be achieved, as compared to conventional receivers perforated with ducts of constant cross-section. A finite element program is being developed to calculate stationary heat transfer in the tapered ducts by free and forced convection in the gas flow, conduction in walls and in the gas, and solar and thermal radiation. Gas and wall temperatures are considered to be varying only in the flow direction. In order to perform the highly nonlinear calculations of radiative exchange, the exact knowledge of the view factors is necessary. The aim of the present work is to evaluate analytically the view factors in tapered ducts.

Energy Technology Data Exchange (ETDEWEB)

Palmitic acid (PA, 59.8 {sup o}C) and lauric acid (LA, 42.6 {sup o}C) are phase change materials (PCM) having quite high melting temperatures which can limit their use in low temperature solar applications such as solar space heating and greenhouse heating. However, their melting temperatures can be tailored to appropriate value by preparing a eutectic mixture of the lauric and the palmitic acids. In the present study, the thermal analysis based on differential scanning calorimetry (DSC) technique shows that the mixture of 69.0 wt% LA and 31 wt% PA forms a eutectic mixture having melting temperature of 35.2 {sup o}C and the latent heat of fusion of 166.3 J g{sup -1}. This study also considers the experimental determination of the thermal characteristics of the eutectic mixture during the heat charging and discharging processes. Radial and axial temperature ...

International Nuclear Information System (INIS)

Gross electricity production in 1993 in the OECD (including generation from pumped storage plants) was 7 466 TWh, a rise of 1.2 per cent from the level of gross production in 1992 (Tables 1 and 3). Nuclear plants accounted for 24.2 per cent of total gross electricity production in 1993, hydroelectric plants 16.7 per cent, total thermal plants 58.7 per cent and geothermal and other renewables 0.4 per cent. In 1992 total OECD heat production that is sold to third parties by public producers was 25 Mtoe (Table 6). About 86 per cent of this heat (21.6 Mtoe) was produced in CHP plants, about 12 per cent (3.1 Mtoe) in heat plants, and the remainder (0.3 Mtoe) in nuclear power plants (in Canada and Switzerland only). Based on preliminary data, apparent consumption of electricity (gross production plus imports less exports) in 1993 in OECD was 7 474 TWh. The corresponding figure for 1992 was 7 379 TWh, indicating a rise of 1.3 per ...

Energy Technology Data Exchange (ETDEWEB)

This paper presents the experimental measurements of the transmittivity of commercial grade stearic acid. The effects of temperature and thickness on transmittance have been studied. The study indicates that the effect of temperature on the transmittance of stearic acid in the liquid phase is not significant. However, it is highly dependent on temperature during the solidification process. Because of its low thermal conductivity and high transmittivity, it can be used as a transparent insulating material. (Author)

Energy Technology Data Exchange (ETDEWEB)

A research report describes the energy efficiency techniques to be employed in designing a building which is ``green``. Topics covered include building fabric performance, ventilation and infiltration, passive solar design, heating systems and controls, hot and cold water provision, lighting and electrical appliances. (UK)

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study is to determine the thermal reliability of stearic acid, palmitic acid, myristic acid and lauric acid as latent heat energy storage materials with respect to various numbers of thermal cycles. The fatty acids, as phase change materials (PCMs), of industrial grade (purity between 90% and 97%) were subjected to accelerated thermal cycle tests. The differential scanning calorimetry (DSC) analysis technique was applied to the PCMs after 0, 120, 560, 850 and 1200 melt/freeze cycles in order to measure the melting temperatures and the latent heats of fusion of the PCMs. The DSC results indicated that the change in melting temperature for the PCMs was in the range of 0.07-7.87 {sup o}C, and the change in latent heat of fusion was -1.0% to -27.7%, except for stearic acid between 560 and 1200 melt/freeze cycles. However, the decrease in the latent heats of fusion for all the PCMs was ...

Energy Technology Data Exchange (ETDEWEB)

A unified model is presented for a class of combined energy systems, in which the systems mainly consist of a heat engine, a combustor and a counter-flow heat exchanger and the heat engine in the systems may have different thermodynamic cycle modes such as the Brayton cycle, Carnot cycle, Stirling cycle, Ericsson cycle, and so on. Not only the irreversibilities of the heat leak and finite-rate heat transfer but also the different cycle modes of the heat engine are considered in the model. On the basis of Newton's law, expressions for the overall efficiency and power output of the combined energy system with an irreversible Brayton cycle are derived. The maximum overall efficiency and power output and other relevant parameters are calculated. The general characteristic curves of the system are presented for some given parameters. Several interesting ...

Energy Technology Data Exchange (ETDEWEB)

Organic Rankine cycles (ORC) have unique properties that are well suited to solar power generation. In this work design and performance calculations are performed using MatLab/SimuLink computational environment. The cycle consists of thermal solar collectors (Flat Plate Solar Collector (FPC), or Parabolic Trough Collector (PTC), or Compound Parabolic Concentrator (CPC)) for heat input, expansion turbine for work output, condenser unit for heat rejection, pump unit, and Reverse Osmosis (RO) unit. Reverse osmosis unit specifications used in this work is based on Sharm El-Shiekh RO desalination plant. Different working fluids such as: butane, isobutane, propane, R134a, R152a, R245ca, and R245fa are examined for FPC. R113, R123, hexane, and pentane are investigated for CPC. Dodecane, nonane, octane, and toluene are allocated for PTC. The proposed process units are modeled and show a ...

Energy Technology Data Exchange (ETDEWEB)

The present paper deals with the conversion of solar energy in a gas turbine plant with a parabolic dish collector. Particular consideration is devoted to the thermodynamic and mechanical design and partload behavior of the receiver. The incident sunlight is focussed by the parabolic dish and then beamed into the cavity receiver. Here the working medium of the gas turbine flows through tubes and is heated up to the receiver outlet temperature. The task of the receiver is to transfer the radiated energy as efficiently as possible to the working medium. Furthermore the required heating surface should be small as possible i.e. optimum use must be made of the tube material with respect to its state of stress. It is shown which geometric and thermodynamic plant parameters influence these two design criteria. An optimum receiver design is presented on the basis of the results thus obtained. Finally, the variations in receiver ...

Energy Technology Data Exchange (ETDEWEB)

The merits of single stage absorption heat pumps coupled to simple distillation for effluent treatment are discussed. An experimental integrated absorption heat pump effluent purification system (IAHPEPS) was built and operated with water-lithium bromide as a working mixture. This unit has been used to raise the temperature and hence, the vapour pressure of the impure water contained in one vessel, to the point where pure water vapour will distil from impure effluent solution (tap water or brine) and condense in a second vessel used to collect pure water. Pure effluent production rates of between 0.5 and 4.3 kg h{sup -1} were obtained. The actual coefficient of performance (COP{sub A}) and the heat pump effectiveness varied from 1.1 to 1.4 and 0.58 to 0.72, respectively. The results from the small scale systems indicate the likely results from industrial scale units which could be operated with low quality ...

British Library Electronic Table of Contents (United Kingdom)

In recent years, increased attention has been focused on the use of lasers in different fabrication steps of solar cells, in particular laser doping to form emitter and/or selective emitter. In this method the laser energy is used to melt silicon, allowing the diffusion of dopant atoms to occur in the liquid phase. The main advantage of this method is the localised nature of the laser beam, which melts and diffuses a limited area without heating the bulk, therefore reducing the possible degradation associated with high temperature processes. At the University of New South Wales a novel laser doping method was developed, which combines the formation of the selective emitter with a self-aligned metallisation pattern. Despite achieving high efficiencies, concerns arose regarding the adhesion ...

Energy Technology Data Exchange (ETDEWEB)

This paper investigates the phase change behavior of 65 mol% capric acid and 35 mol% lauric acid, calcium chloride hexahydrate, n-octadecane, n-hexadecane, and n-eicosane inside spherical enclosures to identify a suitable heat storage material. Analytical models are developed for solidification and melting of sphere with conduction, natural convection, and heat generation. Both the models are validated with previous experimental studies. Good agreement was found between the analytical predictions and experimental study and the deviations were lesser than 20%. Heat flux release at the wall, cumulative energy release to the external fluid, are revealed for the best PCM. The influence of the size of encapsulation, initial temperature of the PCM, the external fluid temperature on solidified and molten mass fraction, and the total phase change time are also investigated. (author)

Energy Technology Data Exchange (ETDEWEB)

Laser-assisted processing techniques, utilized to produce fine, metal grid patterns for high-efficiency solar cells, are being investigated, developed, and characterized. The work performed in the third quarter of this contract is detailed here. A preliminary economic evaluation has yielded the conclusion that laser-assisted pyrolysis of spun-on silver neodecanoate is the most promising of all the metallization techniques being investigated in this contract. Early adhesion problems have been solved by optimizing deposition parameters. Linewidth studies have been carried out as a function of laser power, scan speed, and film thickness. Preliminary solar cells have been fabricated and characterized using this metallization scheme. Silver neodecanoate films have also been decomposed using a pulsed uv laser and metal mask. A detailed study of the various models of localized surface temperature rise in silicon due to laser ...

Energy Technology Data Exchange (ETDEWEB)

A 1,200 bird solar chicken brooder was indigenously designed and operated by the Indian scientists for the first time in the country as a Project under funding by the Ministry of Non Conventional Energy Sources to the All India Women`s Conference. This multi disciplinary project was taken up on the International Sun Day, May 3, 1993 and completed on May, 1994. Data has been collected for the first nine months of operation. Its successful operation has justified multi disciplinary approach. The solar chicken brooder incorporates modern poultry concepts of breeding under controlled temperatures. In view of the mixed climate of Delhi, provision was made for heating and cooling both to take care of the 24 hour cycle. Comfort conditions have been identified and maintained (as is done in the their genetic characteristics) at different temperatures for a period of 8--10 weeks to grow them to a uniform weight of 2.0 kg. Growing ...

Science.gov (United States)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

Vaarst Vestervang (Denmark) comprises 16 villas and 1 communal building. The complex was designed by the inhabitants themselves with the aim of polluting the environment as little as possible. The land area constitutes 69.000 square meters where it is possible to grass animals. The document reports a measuring programme concerning the overall heat consumption as one of the main aims of the inhabitants is to save energy and thus contribute to the protection of the environment. The capacity of the solar collectors predominantly used in the building complex was 235 kWh/m{sup 2}. Supplementary heating is provided by boilers fired with wood. The measuring system is described in detail. Tables show the influence of heat transmission losses, ventilation, airing out of rooms, the angle of the sun`s rays within the buildings and heating needs on energy consumption. Energy consumption data is ...

Science.gov (United States)

A possible receiver configuration is a cavity in which a falling sheet of solid particles is directly irradiated by the concentrated solar flux passing through the aperture. Regardless of the particular geometry, the radiative transfer within the falling particle curtain must be studied in order to determine the net radiative heating rate for the particles. A discrete ordinate radiative transfer model has been developed to predict the radiative coupling within the falling particle curtain. The model determines how much energy is absorbed by the particles, how much is transmitted to the rear wall of the receiver, and determines the effects of particle scattering and thermal emission on the net radiation absorbed by the particles. The model accounts for the directional nature of the radiation field, particle scattering, and the wavelength dependence of the optical properties. The discrete ordinate model has been used to assess the influence of ...

Energy Technology Data Exchange (ETDEWEB)

Considerable potential exists for increasing the annual efficiency of line-focus collectors by reducing receiver heat losses. Five alternate receiver designs are compared with a standard design. The comparison is based on annual collector-field efficiency using optimized receiver designs. Of the receivers studied, the all-glass design and the cavity design provide the greatest increases in efficiency. Average fluid temperatures range from 200/sup 0/ to 450/sup 0/C. As a guide for further study, areas of uncertainty and potential problems are identified.

Energy Technology Data Exchange (ETDEWEB)

A simple theory for predicting the convective energy loss from side-facing cavity receivers in windless environments has been developed. The approach used is to determine the velocity distribution of the incoming air in the aperture plane (and thereby the rate of mass entrainment); and then to estimate the bulk temperature of the heated emerging air. The convective loss is then calculated from an energy balance. To illustrate this theory, numerical results applicable to the 2.15 meter cubic cavity being tested in the laboratory are provided.

Energy Technology Data Exchange (ETDEWEB)

This paper analyses the errors caused by interpolation from existing cases for assessing indoor air flow, air quality and thermal comfort in an office. A sensitivity study is then provided to determine the influence of several boundary conditions on indoor air diffusion. The research is conducted numerically by using a low-Reynolds-number k-{epsilon} model. It can be concluded that the interpolation errors caused by the variations of solar radiation, window size, heat source location due to lighting, and the surface temperatures of interior walls are small and can be quantitatively determined. But it is difficult to estimate the errors introduced by the variations of furniture location and size. (author).

Energy Technology Data Exchange (ETDEWEB)

In an ideal system the surface of the dish is perfectly parabolic (no contour flaws are present), and the sun rays fall on the dish surface parallel to the focal axis (no sun tracking flaws are present). These two conditions are not realizable in practice; in this case, the parabolic dish system is called real system. In this paper a procedure for analysing the flux distribution on the receiver internal surfaces is presented for a cavity receiver with a real parabolic dish collector. First, the theoretical principles are discussed. Then the effect of the inaccuracy in the collector and in the sun tracking on the insolation pattern is described using an example.

Science.gov (United States)

The change in the energy flow on land used for brown coal mining is examined. Terrain mapping was used to obtain land use data for a 14 km{sup 2} mining area and its surroundings. The focus is on the proportion of incident solar energy that is changed to latent heat during evapotranspiration. Each land use unit was assigned an average value for evapotranspiration for the growing season. Satellite data of surface temperature and surface wetness values show incident radiation converted to heat. Relationships between evapotranspiration and surface temperature and between wetness index and evapotranspiration were verified. The results confirm the hypothesis that changes in land use can have a significant effect on total average evapotranspiration. 18 refs., 5 figs., 3 tabs.

British Library Electronic Table of Contents (United Kingdom)

Abstract Satellite measurements and numerical forecast model reanalysis data are used to compute an updated estimate of the cloud radiative effect on the global multi-annual mean radiative energy budget of the atmosphere and surface. The cloud radiative cooling effect through reflection of short wave radiation dominates over the long wave heating effect, resulting in a net cooling of the climate system of - 21 Wm-2. The short wave radiative effect of cloud is primarily manifest as a reduction in the solar radiation absorbed at the surface of - 53 Wm-2. Clouds impact long wave radiation by heating the moist tropical atmosphere (up to around 40 Wm-2 for global annual means) while enhancing the radiative cooling of the atmosphere over other regions, in particular higher latitudes and sub-trop...

Energy Technology Data Exchange (ETDEWEB)

This thesaurus contains the vocabulary used to index the Biomass Database maintained by the IEA Biomass Conversion Technical Information Service. The database, which is used to produce Biomass Abstracts, contains indexed and abstracted references to the published literature relating to biomass energy including cultivations, harvesting, materials handling, conversion techniques, environmental aspects and economics.

Energy Technology Data Exchange (ETDEWEB)

The project is described, the motivation for the research and the microclimate is defined in relation to both building physics research and applications. Air temperatur, air humidity, solar radiation and air velocity are briefly considered, whilst driving rain and long-wave radiation are described in more detail. Convective heat transfer and surface coefficients are discussed, although they are not microclimatic factors, merely resulting from combinations of such factors. They are included as they are important in relation to transfer of heat and moisture at the surface of the building envelope. Driving rain measurement is the main area of interest, including development of measurement equipment. Long-wave irradiation is measured and compared with empirical formulae from the literature. Window convection heat transfer is another main area of interest. Nocturnal convective heat ...

Energy Technology Data Exchange (ETDEWEB)

The article is the second part of a review dealing with latest developments in the area of solar cell technologies and application. Physical principles, design and efficiency as well as advantages and disadvantages of GaAs- and CdS-solar cells are described. Power generation solar cell systems with voltage converters, combined solar cell/solar collector systems and thermoelectric solar systems are presented in the second part of the article.

Science.gov (United States)

... Solar Cell Radiation Respinnse Near the Interface o~f fliffprerv- ... 5 4. CALCUTl-ATED SOLAR CELL RLSPONSE FOR VARIOUS BASE MATERIALS ...

Energy Technology Data Exchange (ETDEWEB)

The present study deals with two subjects. The first one is to determine the thermal properties of lauric acid (LA)-stearic acid (SA), myristic acid (MA)-palmitic acid (PA) and palmitic acid (PA)-stearic acid (SA) eutectic mixtures as latent heat storage material. The properties were measured by the differential scanning calorimetry (DSC) analysis technique. The second one is to study the thermal reliability of these materials in view of the change in their melting temperatures and latent heats of fusion with respect to repeated thermal cycles. For this aim, the eutectic mixtures were subjected to 360 repeated melt/freeze cycles, and their thermal properties were measured after 0, 90,1 80 and 360 thermal cycles by the technique of DSC analysis. The DSC thermal analysis results show that the binary systems of LA-SA in the ratio of 75.5:24.5 wt.%, MA-PA in the ratio of 58:42 wt.% and PA-SA in the ratio of 64.2:35.8 wt.% form eutectic mixtures ...

Energy Technology Data Exchange (ETDEWEB)

The energy flux distribution at the aperture of cavity receivers is an important parameter that characterizes the performance of point-focusing solar concentrators. Together with simplifying assumptions about cavity absorptance, emittance, and convective losses, good estimates of the dish-receiver collection efficiency as a function of incident flux and effective cavity temperature can be obtained. For detailed design of cavity receivers, however, it is necessary to determine the incident flux distribution on the interior surfaces. This information is needed ultimately to determine the resulting energy fluxes to the working fluid, temperature distributions within the cavity, and receiver performance. Knowing the incident flux distributions provides the designer with insights such as where hot-spots are likely to occur, where heat exchange surfaces are needed, and where more detailed analysis might be warranted. Solar ...

Science.gov (United States)

... nent to the design and construction of metal-semiconductor solar cells, in that both the photovoltage and the efficiency of metal-semiconductor cells ...

Energy Technology Data Exchange (ETDEWEB)

An engineering tool incorporating a scanning infrared radiometer, an image digitizer, a microcomputer, and the software to drive the system was developed to allow remote mapping of the temperature distribution in solar cavity receivers. Using enclosure analysis, the infrared image processing program extracts the irradiance map from the radiosity map of the cavity to yield an emissive power map. Using the calibration curve of the radiometer and the emissivity of the surface of the cavity, the emissive power map is transformed into a temperature map. The system was tested by comparing its calculated temperatures to temperatures measured by thermocouples at several locations on the surfaces of heated model cavity receivers. The average relative error for the cavities ranged from 4.6%--34.9%, with the relative error on the base usually less than half that on the wall. Some work was also carried out to compensate the detected radiosity field for the ...

CERN Document Server

We investigate the formation and evolution of dwarf galaxies in a high resolution, hydrodynamical cosmological simulation of a Milky Way sized halo and its environment. Our simulation includes gas cooling, star formation, supernova feedback, metal enrichment and UV heating. In total, 90 satellites and more than 400 isolated dwarf galaxies are formed in the simulation, allowing a systematic study of the internal and environmental processes that determine their evolution. We find that 95% of satellite galaxies are gas-free at z=0, and identify three mechanisms for gas loss: supernova feedback, tidal stripping, and photo-evaporation due to re-ionization. Gas-rich satellite galaxies are only found with total masses above ~ 5x10^9 solar masses. In contrast, for isolated dwarf galaxies, a total mass of ~ 10^9 solar masses constitutes a sharp transition; less massive galaxies are predominantly gas-free at z=0, more massive, ...

Energy Technology Data Exchange (ETDEWEB)

Chromium containing amorphous hydrogenated carbon films (a-C : H/Cr) have been prepared by simultaneous rf plasma activated chemical vapour deposition of methane and magnetron sputtering of a chromium target. During deposition the substrates were heated (up to 300C) and DC biased (-200 and -600 V) in order to obtain films with high chemical stability. Constant temperature tests were performed at 250C in air with coatings deposited on silicon substrates. The degradation of the coatings was monitored by Raman spectroscopy and reflectance and transmission measurements. The main degradation mechanisms are discussed and the relevant parameters which improve the durability of the coatings are presented. Furthermore, the durability of solar selective, multilayered coatings which were deposited on copper sheets was investigated. Based on accelerated aging tests at different temperature loads in air (at 220C, 250C and 300C) and in a humid environment ...

International Nuclear Information System (INIS)

Natural gas is essential to the world economy. Gas now accounts for almost a quarter of OECD primary energy requirements and is expected to become the second most important fuel in the world in the next decade. Industrial and residential consumers increasingly rely on natural gas to keep their houses warm, their lights on and their factories running. Meanwhile the gas industry itself has entered a new phase. Where gas used to be restricted to regional markets, it is now increasingly traded on a global scale. While gas production and transport requires long-term investment, now it is optimised on a short-term basis. Demand continues to grow, but local gas production has become much more expensive. How should we react? How will demand be satisfied? What changes are required to promote flexibility and trade? What are the implications for gas security, investment and interdependence? At stake is an opportunity to diversify supply and demand - but this goal is threatened by barriers to ...

Wastenet

...Polymer Fuel Cells Challenge Publications News Events Login Register Search Content type All Web pages Case studies Publications News Video Home ...Buildings Carbon capture & storage Combined heat & power Electricity transmission & distribution Energy storage Fuel cells Geothermal Hydroelectric Hydrogen Industry Lighting Marine Metering Nuclear Solar Transport Wind ...Home Emerging technologies Current focus areas Polymer Fuel Cell Challenge Polymer Fuel Cells Challenge The objective of the Polymer Fuel Cells Challenge is to develop,...prove and commercialise novel polymer fuel cell technologies that have the potential to deliver a step-change in overall system cost. What are ...

Energy Technology Data Exchange (ETDEWEB)

Stability and decomposition of PtSi, NiSi, and PdSi in contact with single crystal or amorphous Si is examined. PtSi, PdSi and NiSi are thermally stable both with Si, but are unstable in contact with metal film. It is shown that epitaxial Si layers can be obtained using both Pd and Al as metal film and layers can be electrically doped by the addition of a doping layer to the thin film structure prior to the heat treatment or by inclusion of Al atoms so that n/sup +/ and p/sup +/ conductivity can be achieved in the grown epilayer. The effects of impurities, substrate orientation on the growth kinetics are also discussed. (LEW)

Energy Technology Data Exchange (ETDEWEB)

Despite the current global economic crisis, the Cleantech industry has excellent growth prospects. Especially technologies for water treatment, energy efficiency in buildings and combined heat and power will face high demand and high growth rates in the coming years, just like the suppliers for the wind and solar industry. Today German companies are market leaders in these segments. However, there is a threat that they will lose this competitive position as international competition increases. Besides attractive incentive schemes and regulatory framework, access to venture capital and the fast expansion to international markets is an important factor to secure the leading market position of German Cleantech companies. (orig.)

Energy Technology Data Exchange (ETDEWEB)

The procedure followed by the Laboratorio de Metrologia Nuclear in Sao Paulo, Brazil, for the standardization of {sup 242g} Am is described. The calibration system was composed of a 4 {pi} gas-flow proportional counter coupled to a pair of NaI(Tl) crystals operating in coincidence. The samples were produced by irradiating dried aliquots of {sup 241} Am with thermal and epithermal neutrons at the IEA-R1 research reactor. The efficiency tracer technique has been applied using {sup 60} Co as tracer. The beta detection efficiency was changed by external absorbers and extrapolated to unity by linear least square fitting applying covariance methodology. (author)

Energy Technology Data Exchange (ETDEWEB)

The Westinghouse Electric Corporation has undertaken to investigate, develop, and characterize laser-assisted processing techniques utilized to produce the fine line, thin metal grid structures that are required to fabricate high-efficiency solar cells. Two basic techniques for metal deposition will be investigated, as follows: (1) photochemical decomposition of liquid or gas phase organometallic compounds utilizing either a focused, CW ultraviolet laser (System 1) or a mask and ultraviolet flood illumination, such as that provided by a repetitively pulsed, defocused excimer laser (System 2), for pattern definition, and (2) thermal deposition of metals from organometallic solutions or vapors utilizing a focused, CW laser beam as a local heat source to draw the metallization pattern. The purpose of this contract is to investigate the various existing laser-assisted film deposition techniques in order to develop a new, cost-effective technology ...

Energy Technology Data Exchange (ETDEWEB)

The shortage of fresh water is increasing at alarming levels, even in temperate zones. Desalination of brackish and seawater is being considered as a solution to growing water demands. Seawater desalination can be accomplished through reverse osmosis, vapor compression, vapor absorption and thermally driven systems. The most suitable process for large-scale desalination plants is successive brine evaporation-condensation with intermediate heat recovery. However, higher process efficiency could be achieved. The use of low temperature heat sources in seawater desalination requires an efficient method of evaporation and condensation at relatively low vapor pressures. This could be achieved in a humidification-dehumidification process using circulated air to enhance evaporation of water. Simulation models, however, neglect either the heat of evaporation or the changes in air and water properties within humidification and ...

Energy Technology Data Exchange (ETDEWEB)

Support for raising energy efficiency is reported for the following five areas during 1998-2001: 1. Fuel-based energy systems with the sub-areas: Sustainable production of biofuels, including ash recycling; Cogeneration; and Large scale heat production. 2. Transport with two sub-areas: Internal combustion engines; and Electric drive-lines. 3. Power production/Power technology with the sub-areas: Hydropower; Wind power; Power transmission and distribution; and Photovoltaic solar cells. 4. Industry with the sub-areas: Processes; and Support systems in industry. 5. Buildings with the sub-areas: Heating, cooling and climatic shields; and Components and support systems. In total, 1,800 M SEK (about 180 M USD) was contributed by the Energy Administration during this period. An overview of the projects is presented in this report.

Energy Technology Data Exchange (ETDEWEB)

Thermal absorption with its combined thermal and mechanical loads in a solar receiver does depend significantly on the distribution of incident solar radiation. For a cavity receiver with paraboloid collectar a method is derived which enables the calculation of solar radiation distribution on the areas inside the receiver. The theoretical bases are presented first, and a subsequent example shows the influence of the most important geometric parameters on the distribution of solar radiation.

Energy Technology Data Exchange (ETDEWEB)

In the paper, a potential of solar energy for drying of medicinal plants in Polish conditions is estimated and development of solar drying technologies is presented. The results of economic assessment of flat-plate solar collectors applied for drying of medicinal plants on a farm are promising. In some specific conditions, e.g. drying of wild grown medicinal plants in remote areas, even application of photovoltaic modules for driving of a fan of a solar dryer is a profitable option and enables easy control of the drying air temperature.

Energy Technology Data Exchange (ETDEWEB)

Several technological alternatives have been studied taking into consideration that one of the biggest problems of the electric power companies is to provide electric power during the peak consumption periods, which largest contribution to the increase of the demand comes from the residential sector, especially by the use of electric showers. One of the most promising alternatives is the pre-water heating system for reduced power showers, developed by Universidade de Campinas and Companhia Paulista de Forca e Luz. The goal of this system is basically to reduce demand during the peak periods, in order to avoid heavy investments by the electric power companies in generation, transmission and distribution of electric power directed to low acquisitive power customers, a sector in which the electric power price is not enough to recover such investments. The objective of this paper is to evaluate the total energy required in the construction of one of these systems and ...

Energy Technology Data Exchange (ETDEWEB)

Analyses of process system properties were continued for important chemical materials involved in the several processes under consideration for semiconductor and solar cell grade silicon production. Major activities were devoted to physical, thermodynamic and transport property data for silicon. Property data are reported for vapor pressure heat of vaporization, heat of sublimation, liquid heat capacity and solid heat capacity as a function of temperature to permit rapid usage in engineering. Chemical engineering analysis of the HSC process (Hemlock Semiconductor Corporation) for production of silicon was initiated. The process is based on hydrogen reduction of dichlorosilane (DCS) to produce the polysilicon. The chemical vapor deposition reaction for DCS is faster in rate than the conventional process route which utilizes trichlorosilane (TCS) as the silicon raw material. Status ...

Science.gov (United States)

Manufacture of cadmium sulfide thin film solar cells

Energy Technology Data Exchange (ETDEWEB)

Contents include: index for 1970-1980; January 1981 data -- alert periods, daily solar indices, solar flares, solar radio emission, coronal holes, inferred interplanetary magnetic field polarities, mean solar magnetic field, spacecraft observations, December 1980 data -- daily solar-activity centers, sudden ionospheric disturbances, spacecraft observations, solar radio emission, cosmic rays, geomagnetic indices, radio-propagation indices; late data -- solar radio emission November, December 1980, spacecraft observations November 1980, cosmic rays, Huancayo Oct 1980 -- climax, alert, Deep River Nov 1980.

Science.gov (United States)

Jun 10, 2011 ... The PSSC is a picosatellite designed to test the space environment by providing a testbed to gather data on new solar cell technologies.

Science.gov (United States)

High-Temperature Solar Cell Development. Geoffrey A. Landis,. NASA John Glenn Research Center. 21000 Brookpark Road, Cleveland, OH 44135. Danielle ...

Science.gov (United States)

Metal-semiconductor solar cells reported to date exhibit inherently low output voltages. This effect isa consequence of high diode "saturation" ...

Science.gov (United States)

replacing the KDP crystal, and introducing computer programs for accumulation of an almost unlimited number of frames. The calibration procedure using solar ...

Energy Technology Data Exchange (ETDEWEB)

The information gathered as operating manager when implementing the first photovoltaic rural electrification and technology transfer program carried out to date in the world in French Polynesia from 1978 to 1990 are detailed. The technical developments of equipment and the work in progress at the GENEC Cadarache within French, European or IEA programs in order to improve some components or appliances and make up for certain deficiencies are presented. This involves accelerated aging tests, Standardization work, development of high efficiency equipment. Non technical barriers are often emphasized. Technical barriers also exists. Considerable work in many domains of small PV systems remains to be done so as to combine all the conditions required to implement successful large programs in developed as well as in developing countries.

International Nuclear Information System (INIS)

In this work, the half-life of the "1"5"5Sm #beta#"- decay was determined using enriched "1"5"4Sm samples submitted to irradiation in the IEA-R1 reactor of IPEN; the activity of the samples were followed for 4-5 consecutive half lives using a 198 cm"3 HPGe detector. The data was corrected using a non paralizable dead time correction and fitted to an exponential decay function using a non linear fitting procedure developed on the MatLab platform. The resulting value--T_1_/_2 = 22.180(26) min--was compatible to the one found in the literature, with a lower uncertainty.

Energy Technology Data Exchange (ETDEWEB)

Both travelers were members of a nine-person US delegation that participated in an international workshop on accelerator-based 14 MeV neutron sources for fusion materials research hosted by the University of Tokyo. Presentations made at the workshop reviewed the technology developed by the FMIT Project, advances in accelerator technology, and proposed concepts for neutron sources. One traveler then participated in the initial meeting of the IEA Working Group on High Energy, High Flux Neutron Sources in which efforts were begun to evaluate and compare proposed neutron sources; the Fourth FFTF/MOTA Experimenters' Workshop which covered planning and coordination of the US-Japan collaboration using the FFTF reactor to irradiate fusion reactor materials; and held discussions with several JAERI personnel on the US-Japan collaboration on fusion reactor materials.

Science.gov (United States)

No Abstract Available

Science.gov (United States)

Orbital maintenance parameters for individual satellites or groups of satellites have traditionally

Science.gov (United States)

Not Available

Energy Technology Data Exchange (ETDEWEB)

A preliminary study of two different kinds of solar receivers (a rotating cavity receiver and a volumetric receiver) suitable to operate in the 1 kW solar facility at the University of Rome is presented. Possible applications of solar energy in the aluminum extraction from leucite and chemical storage by the CuO/Cu[sub 2]O cycle are presented and discussed. (author).

Science.gov (United States)

Progress made during the first phase effort of the Solar-Thermal Full-System Experiment is summarized. This is one of a number of projects in the Solar-Thermal Subprogram involved with the development of solar central receiver hardware and systems for future use by utilities. The main emphasis is on systems that use Brayton-Cycle (gas turbine) equipment. The project summarized involves the planning and design of a complete Brayton-Cycle solar central receiver experimental system that would include all components of a commercial-size electric utility solar power plant. The objective of the overall project is to demonstrate the technical feasibility of a complete Brayton-Cycle, solar-fossil hybrid central receiver system. Major objectives of the Phase I effort summarized are to plan and design the experiment in detail and to organize a utility Test and Operating ...

Energy Technology Data Exchange (ETDEWEB)

The proposed aim of the work is to verify the effects produced on different kinds of environmental pollutants after exposure to a low frequency radiation such as microwaves. They have proved capable of producing minimum heating of the matrix as well as modifications in the structure of the molecules at the level of simple bonds. Steps were also taken ti check whether the degradation action of the microwaves could be boosted by sunlight. For this reason tests were run also on samples irradiated using microwaves and a lamp capable of simulating the sun's spectrum, as well as in the presence of a single lamp. [Italian] Lo scopo di questa ricerca e' di verificare gli effetti prodotti su inquinanti ambientali, di diversa natura, a seguito di un'esposizione ad una radiazione a bassa frequenza come le microonde. Le microonde possono produrre minimi riscladamenti della matrice e modificazioni della struttura delle molecole, a livello di legami ...

Energy Technology Data Exchange (ETDEWEB)

Three agricultural applications in a specially designed greenhouse solar system functioning as a multi-purpose solar air collector for crop production and curing/drying processes are examined. An automated hydroponic crop production system is proposed for the greenhouse solar system. Design criteria of the proposed system and its utilization of solar energy for root-zone warming are presented and discussed. Based upon limited testing of the hydroponic system considered, hydroponic production of greenhouse crops is believed reasonable to complement the year-round use of the greenhouse solar system. The hardware/software design features of a microcomputer-based control system applied in the greenhouse solar barn are presented and discussed. On-line management and utilization of incident solar energy by the microcomputer system are investigated ...

Energy Technology Data Exchange (ETDEWEB)

The present study includes thermal stability of some fatty acids as phase change materials (PCMs). The selected fatty acids were stearic, palmitic, myristic and lauric acid with melting temperatures between 40-63{sup o}C and industrial-grade with 90-95% purity. Latent heat storage capacity and phase transition temperature of the PCMs were determined by Differential Scanning Calorimetry (DSC) technique as a function of after repeated thermal cycles such as 40, 410, 700 and 910. The present work also comprises the investigation of corrosion resistance of some construction materials to the fatty acids over a long period. The containment materials tested were stainless steel (SS 304 L), carbon steel (steel C20), aluminium (Al) and copper (Cu). Gravimetric analysis as mass loss (mg/cm{sup 2}), corrosion rate (mg/day) and a microscopic or metallographic investigation were performed for corrosion tests after 910 thermal cycles. DSC measurements showed that all fatty acids ...

Energy Technology Data Exchange (ETDEWEB)

The Active Magnetospheric Particle Tracer Explorers (AMPTE) program provided important information on the behavior of clouds of plasma artificially injected into the solar wind and the earth's magnetosphere. Now that the releases are over, data from the satellites are being analyzed to investigate the processes by which the ambient solar wind mass, momentum, and energy are transferred to the magnetosphere. Work in progress at APL indicates that the solar wind is much more inhomogeneous than previously believed, that the solar wind constantly buffets the magnetosphere, and that ground observers may remotely sense these interactions as geomagnetic pulsations. 8 refs.

Energy Technology Data Exchange (ETDEWEB)

The invention concerns a solar power station with a hollow solar heater, which has reflected radiation coming in, focussed by a mirror through the inlet opening. To match the differing solar radiation during the day, the inlet opening can be adjusted by changing its cross-section. This is done by at least two thick flat circular parts which can move relative to each other which are preferably movable relative to each other in pairs on a common rail and which are cooled by a coolant which is the working medium for absorbing solar energy.

Energy Technology Data Exchange (ETDEWEB)

As concern regarding global environmental problems such as the greenhouse effect and acid rain has increased, so too has the demand for commercially viable solar cells as a clean energy source. Interest in amorphous silicon (a-Si) solar cells has been particularly high, due to their low cost. Technological developments in the field of a-Si solar cells are discussed from the viewpoints of fabrication process, materials, and cell structures. Various applications and systems that take advantage of the a-Si solar cell are then introduced. Finally, future prospects are mentioned

Energy Technology Data Exchange (ETDEWEB)

The solar energy industry experienced unprecedented growth in the eight years from 2000 to 2007, with explosive growth occurring in the latter half of this period. From 2004 to 2007, global private sector investment in solar energy increased by almost twenty-fold, marking a dramatic increase in the short span of four years. This paper examines the timing, magnitude, focus and location of various forms of investment in the solar energy sector. It analyzes their trends to provide an understanding of the growth of the solar industry during the past eight years and to identify emerging themes in this rapidly evolving industry.

Energy Technology Data Exchange (ETDEWEB)

Mixtures of organic-inorganic substances are studied for their performance as energy storage media. Use is made of the fact that organic substances give higher amounts of energy but within a wide range of temperature on the one side and the fact that inorganic substances give lower amounts of energy at constant temperature on the other side. Mixtures of both types of substances, in different ratios, are investigated for the object of determining that optimum composition which stores a higher amount of energy and, meanwhile, releases it at a constant temperature or within a narrow range of temperature. The mixtures used are composed of Glauber`s salt (Na{sub 2}SO{sub 4}.10H{sub 2}O) and stearic acid in different proportions. The effect of cooling fluid flow rate and ambient temperature as well as the effect of addition of a nucleating agent is studied. The results showed that the highest amount of energy stored could be obtained from a mixture containing 40% stearic acid and 60% ...

International Nuclear Information System (INIS)

A 2007 report compiled by members of the armed services indicates that climate change presents a serious security threat to the American public as well as to United States military operations. It is likely that climate change will increase global tensions and competition for resources. This presentation discussed advanced research and technology programs conducted by the National Aeronautics and Space Administration (NASA). Scientists and engineers at NASA have developed a number of technologies that may contribute to American energy security. Advanced energy research and development programs initiated by the organization include advanced heat engines; wind turbines; batteries and electric cars; solar photovoltaics; and fuel cell technologies. NASA's aeronautics and space exploration program has several capabilities relevant to advanced wind power systems. A collaborative program is currently underway to develop airborne wind turbines designed ...

Energy Technology Data Exchange (ETDEWEB)

The humidification dehumidification desalination process is viewed as a promising technique for small capacity production plants. The process has several attractive features, which include operation at low temperature, ability to utilize sustainable energy sources, i.e. solar and geothermal, and requirements of low technology level. This paper evaluates the characteristics of the humidification dehumidification desalination process as a function of operating conditions. A small capacity experimental system is used to evaluate the process characteristics as a function of the flow rate of the water and air streams, the temperature of the water stream and the temperature of the cooling water stream. The experimental system includes a packed humidification column, a double pipe glass condenser, a constant temperature water circulation tank and a chiller for cooling water. The water production is found to depend strongly on the hot water temperature. Also, the water ...

Energy Technology Data Exchange (ETDEWEB)

A lightweight, low permeability liner for graphite epoxy composite compressed gas storage vessels. The liner is composed of polymers that may or may not be coated with a thin layer of a low permeability material, such as silver, gold, or aluminum, deposited on a thin polymeric layer or substrate which is formed into a closed bladder using torispherical or near torispherical end caps, with or without bosses therein, about which a high strength to weight material, such as graphite epoxy composite shell, is formed to withstand the storage pressure forces. The polymeric substrate may be laminated on one or both sides with additional layers of polymeric film. The liner may be formed to a desired configuration using a dissolvable mandrel or by inflation techniques and the edges of the film seamed by heat sealing. The liner may be utilized in most any type of gas storage system, and is particularly applicable for hydrogen, gas mixtures, and oxygen used for vehicles, fuel ...

Science.gov (United States)

Development of a high performance air heater through use of an evacuated tube cover design is described. The cover design utilizes evacuated fluorescent light tubes laid parallel in a close packed array to form an inner transparent glazing over a conventional metal absorber plate with flow behind the plate. A tempered flat glass plate was used as an outer glazing. Both clear and infrared reflective (IR) tubes were investigated. Solar transmittance tests indicate that the clear tube array has a higher transmittance than two flat sheets of low-iron glass. The IR coating produced substantial transmittance loss. Thermal conductance tests indicate that the tubes behave similar to two flat glass sheets with a vacuum in between. The IR reflective coating was only marginally effective at reducing heat conductance. Final prototype designs are presented along with collector performance estimates.

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Major advances in 'Energy and Materials Cycles' have been achieved in the removal of heavy metals from the solid residues of municipal waste incineration. It has been conclusively shown that the oxidation/reduction conditions established during the thermal treatment of filter ash have a decisive influence on the evaporation of groups of heavy metals. With respect to biomass gasification, studies have been carried out with respect to the best way of extracting pure hydrogen from the low calorific value gas that is typically obtained from a biomass gasifier. The overarching goal of the laboratory 'High Temperature Solar Technology' is the use of solar energy for the production of solar fuels, or for the reduction of CO{sub 2} emissions in large scale industrial processes that are conventionally carried out with the use of fossil fuels. In a short-term project targeted at the ...

Energy Technology Data Exchange (ETDEWEB)

A laser beam apparatus and method for analyzing, inter alia, the current versus voltage curve at the point of illumination on a solar cell and the open circuit voltage of a solar cell. The apparatus incorporates a lock-in amplifier, and a laser beam light chopper which permits the measurement of the AC current of the solar cell at an applied DC voltage at the position on the solar cell where the cell is illuminated and a feedback scheme which permits the direct scanning measurements of the open circuit voltage. The accuracy of the measurement is a function of the intensity and wavelength of the laser light with respect to the intensity and wavelength distribution of sunlight and the percentage the dark current is at the open circuit voltage to the short circuit current of the solar cell.

Energy Technology Data Exchange (ETDEWEB)

NASA and DOE plan a cooperative team effort with industry, government laboratories and universities to develop a near term, low cost, low power (100 watt electric class), low mass (<10 kg), advanced radioisotope space power source (ARPS) and in the process reduce the plutonium-related costs as well. The near term is focused on developing an advanced energy converter to use with the General Purpose Heat Source (GPHS). The GPHS was developed and used for the current radioisotope thermoelectric generators (RTGs). Advanced energy converter technologies are needed as a more efficient replacement for the existing thermoelectric converters so that the space radioisotope power source mass and cost can be reduced. a more advanced technology space radioisotope power system program is also planned that addresses a longer-term need. Twenty first century robotic scientific information missions to the outer planets and beyond are planned to be accomplished with ...

Energy Technology Data Exchange (ETDEWEB)

A discussion is given in a popular manner of the solar powered aircraft Solair I. The achievements of the designer are detailed, and trial runs leading up to the first successful flight are given. Technical data of Solair I are listed, and brief news items about it are presented.

Energy Technology Data Exchange (ETDEWEB)

Performance and operating characteristics are presented for a solar powered aircraft intended to remain aloft for long periods. The critical technologies which limit the performance are identified. By using the techniques presented, the effects of variation in the system parameters are studied. Practical design consideration are discussed.

Energy Technology Data Exchange (ETDEWEB)

A brief overview of the conceptual design of a solar central receiver system integrated with an existing cogeneration facility is provided. A synopsis of the performance and economic evaluation, and an assessment of the concept from the site owner's perspective are given.

Science.gov (United States)

car running down the track." Choosing to focus on the design of a hydrogen fuel cell model car rather than a solar race car was a deliberate decision for team, "Larry the...

Energy Technology Data Exchange (ETDEWEB)

Amorphous silicon solar cells have been shown to have efficiencies which degrade as a result of long exposure to light. Annealing such cells in air at a temperature of about 200.degree. C. for at least 30 minutes restores their efficiency.

Energy Technology Data Exchange (ETDEWEB)

Laser-assisted processing techniques for producing high-quality solar cell metallization patterns are being investigated, developed, and characterized. The tasks comprising these investigations are outlined.

UK PubMed Central (United Kingdom)

PurposeTo describe ocular findings for a 34-year-old man with chronic solar retinopathy using high-speed ultrahigh-resolution (UHR) optical coherence tomography (OCT).Full Text Available

Science.gov (United States)

During Phase II multi-junction solar cell will be grown on the large grain thin film produced during Phase I on flexible/low cost metal foil substrate. ...

Energy Technology Data Exchange (ETDEWEB)

In this report, the main emphasis is given to (1) the problems associated with the basic calibration of the spectroradiometer and (2) the year-to-year variability of the calibrations of the solar UV network radiometers. Also, the results from intercomparisons of the Brewer and OL 742 spectroradiometers are included

Science.gov (United States)

ADVANCED MODELING, S IMULATION, AND ANALYSIS (ROADMAP 14). ...... Metal/Silicon Extraction from Regolith & manufacturing ..... addresses solar power, energy storage (in conjunction with solar power and as a prime source of ...

Energy Technology Data Exchange (ETDEWEB)

In this note it is suggested that binuclear platinum(II) complexes with a solely inorganic bridging pyrophosphito ligand also possess many of the complementary advantages of inorganic and organic dyes. They are evaluated for their potential use as a luminescent solar concentrator material. The disadvantages include: the high cost of platinum; the absorption spectra in solution shows a weaker absorption at 452 nm which may cause reabsorption of emitted light; the positions of the absorption and emission maxima are not at the optimal wavelengths for absorption of sunlight and emission to a solar cell. In spite of these drawbacks the author believes the platinum complexes merit consideration for fabrication of solar concentrator devices.

Energy Technology Data Exchange (ETDEWEB)

A rocket borne experiment to measure the temperature structure of the inner solar corona via the doppler broadening of the resonance hydrogen Lyman-..cap alpha.. (lambda1216A) radiation scattered by ambient neutral hydrogen atoms was attempted during the 16 Feb 1980 solar eclipse. Two Nike-Black Brant V sounding rockets carrying instrumented payloads were launched into the path of the advancing eclipse umbra from the San Marco satellite launch platform 3 miles off the east coast of Kenya.

Energy Technology Data Exchange (ETDEWEB)

Flexible solar cells or luminous foils have become reality with organic electronic systems.

Energy Technology Data Exchange (ETDEWEB)

Four topics in nuclear astrophysics, namely; pulsars, star evolution, nucleosynthesis and solar neutrinos are reviewed through the discussion of the observational data.

International Science & Technology Center (ISTC)

The Development of Basic Plasma-Chemical Technology for Manufacture of Low Cost Crystal Silicon for Solar Power Plants.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

This proceedings volume contains contributions by about 70 authors on market trends, funding, marketing, boundary conditions and sales promotion of thermal solar energy and photovoltaic systems. The contributions reflect the diversity of authors, e.g. consultants, advocates and agents of solar technology producers and financial organisations. Central issues were markets in and outside Europe, quality assurance, interdepartmental cooperations, and marketing strategies of the solar industry. The proceedings volume also contains the conference schedule and self-descriptions of the authors' institutions. (orig.)

Energy Technology Data Exchange (ETDEWEB)

This publication of the Areva Group, a world nuclear industry leader, provides information on the energy in many domains. This issue deals with the nuclear fuel cycle, the biofuels, the everyday geothermal power, the Unites States energy supply and types, the Bertrand Picard solar aircraft, the kyoto protocol and the wind power leaders. A special chapter is devoted to the renaissance of solar homes. (A.L.B.)

Energy Technology Data Exchange (ETDEWEB)

Literature summarizing a study on the Saudi Arabian solar controlled environment agriculture system is presented. Specifications and performance requirements for the system components are revealed. Detailed performance and cost analyses are used to determine the optimum design. A preliminary design of an engineering field test is included. Some weather data are provided for Riyadh, Saudi Arabia. (BCS)

Energy Technology Data Exchange (ETDEWEB)

The results of tests performed on the FMC Fresnel-Belt Solar Collector at the Midtemperature Solar Systems Test Facility are summarized. Tests were conducted over a temperature range from 100 to 250/sup 0/C. Test objectives are defined, test procedures are described, and test results and conclusions are given.

Energy Technology Data Exchange (ETDEWEB)

Two general categories are discussed concerning the evolution of the solar system: the dualistic view, the planetesimal approach and the monistic view, the nebular hypothesis. The major points of each view are given and the models that are developed from these views are described. Possible applications of gamma ray astronomical observations to the question of the dynamic evolution of the solar system are discussed.

British Library Electronic Table of Contents (United Kingdom)

This paper looks at the various battery technologies available for use in solar assist plug-in hybrid electric tractors In this context, solar assist plug-in hybrid electric tractors are those that may be used in light-duty agricultural operations. To determine the most suitable battery, four common technologies are analyzed looking at the environmental life-cycle effects and costs.

Energy Technology Data Exchange (ETDEWEB)

The Detartment of Energy's National Solar Data Program established solar energy systems in residential and commercial buildings across the United States. These solar sites are linked to Vitro Laboratories Division's computer in the National Solar Data Network (NSDN). Vitro collects and analyzes data from this network to determine the thermal performance of each of the solar systems. Environmental information collected at the sites for the month of August 1980 is presented. The environmental data for the NSDN are presented in the form of tables for each solar site. The solar sites are grouped into 12 zones, each of which consists of several adjacent states. The solar energy sites are in alphabetical sequence within each zone. The tables provide available meteorological data for reporting sites in the ...

Energy Technology Data Exchange (ETDEWEB)

Installation of the electrical equipment at the Barstow Solar Pilot Plant is the concern of this construction package. Technical specifications for power and instrument cables, meteorological instruments, and control cables are defined. The documentation requirements are briefly discussed.

Science.gov (United States)

... turbine blade heat-transfer and study the heat-transfer augmentation in idealized geometry and its ... responsible for heat transfer augmentation. ...

Energy Technology Data Exchange (ETDEWEB)

In this work, we describe the fabrication and operating characteristics of GaAs/AlGaAs thin film solar cells processed by the epitaxial liftoff (ELO) technique. This technique allows the transfer of these cells onto glass substrates. The performance of the lifted-off solar cell is demonstrated by means of electrical measurements under both dark and illuminated conditions. We have also optimized the light trapping conditions in this direct-gap material. The results show that good solar absorption is possible in active layers as thin as 0.32 {mu}m. In such a thin solar cell, the open circuit voltage would be enhanced. We believe that the combination of an epitaxial liftoff thin GaAs film, and nano-texturing can lead to record breaking performance. {copyright} {ital 1997 American Institute of Physics.}

Energy Technology Data Exchange (ETDEWEB)

This paper describes in an apparatus for absorbing a beam of concentrated solar energy and which includes a cavity receiver with an inlet for transmission thereinto of solar radiation, a protective apertured shield means about the inlet. It comprises: rigid support means fixed to the periphery of the inlet and projecting radially inwardly therefrom to define a generally central aperture area through which the solar radiation can pass into the cavity receiver; and non-structural blanket means spread over the rigid support means between the periphery of the inlet and the aperture area, the material having a high temperature capability and providing for infra-red radiation insulation, while remaining relatively cool when subjected to solar radiation.

British Library Electronic Table of Contents (United Kingdom)

An energy transfer and conversion model for high-temperature solar cavity receivers has been developed using the transport behaviour of solar radiation as described by the spectral radiative exchange factors. A Monte-Carlo ray-tracing method coupled with optical properties was adopted, to predict radiation characteristics of the solar collector system by calculating radiative exchange factors. A cavity receiver with a plano-convexo quartz window was proposed, based upon the directional characteristics of the focal flux and the redistribution effect of the quartz window. Parametric studies on the windowed receiver provided a more uniform flux distribution, higher efficiency and lower loss than the windowless receivers. The predicted results serve as a design reference for the solar receiver...

Energy Technology Data Exchange (ETDEWEB)

Unmanned Aerial Vehicles (UAV) are being proposed for many applications including surveillance, mapping and atmospheric studies. These applications require a lightweight, low speed, medium to long duration airplane. Due to the weight, speed, and altitude constraints imposed on such aircraft, solar array generated electric power is a viable alternative to air-breathing engines. Development of such aircraft is currently being funded under the Environmental Research Aircraft and Sensor Technology (ERAST) program. NASA Lewis Research Center (LeRC) is currently building a Solar Electric Airplane to demonstrate UAV technology. This aircraft utilizes high efficiency Applied Solar Energy Corporation (ASEC) GaAs/Ge space solar cells. The cells have been provided by the Air Force through the ManTech Office. Expected completion of the plane is early 1995, with the airplane currently undergoing flight testing using ...

Energy Technology Data Exchange (ETDEWEB)

The field of micro unmanned aerial vehicles ({mu}UAVs) has advanced rapidly in recent years. This paper studies the design and construction of a small solar-powered aircraft near the size range of current {theta}UAVs. A number of aspects of their design were analysed, including structural, aerodynamic and propulsion system considerations. The effect of small-scale, low Reynolds number aerodynamics was investigated, and the performance of a range of candidate aerofoils was compared. The integration of a solar power source into the aircraft system was considered a key design issue. Consequently, a number of aircraft configurations were examined, with the intention of optimising the application of solar power in a miniature aircraft. Investigation of improved system components suggests that a practical solar-powered aircraft in the size range below 500 mm maximum linear dimension should be viable given ...

British Library Electronic Table of Contents (United Kingdom)

This paper presents a hybrid solar desalination process of the multi-effect humidification dehumidification and the basin-type unit. The sketch of the hybrid solar desalination process is given. The solar vacuated tube collector is employed in the desalination system, multi-effect humidification dehumidification desalination (HDD) process is plotted according to pinch technology, and then the water rejected from multi-effect HDD process is reused to desalinate in a basin-type unit further. The gain output ratio (GOR) of this system will rise by 2?3 at least through reusing the rejected water. The research proves that the multi-effect HDD has much room to be improved. A hybrid solar desalination process of the multi-effect humidification dehumidification and the basin-type unit should be no...

Energy Technology Data Exchange (ETDEWEB)

To investigate the future problem of oil field operation in the North Sea, the latest trend of the resources and development/production of the oil fields in the North Sea in British and Norwegian territories are outlined. Recoverable crude oil reserves, potential additional crude oil reserves, and undiscovered recoverable reserves of Britain, as well as probable total potential crude oil reserves in British continental shelf are put in order. Outlines of development and production of crude oil are described. The petroleum and gas development by Norway in 1996 is arranged, and outlines of the reserves, development, and petroleum/gas production are given. As the topics relating to the North Sea in 1996, reports are made on: the effective use of existing infrastructure surplus capacity; dealing with economic efficiency; challenge to abysmal development; applied instances of floating production; storage and offloading (FPSO) system to a small-size oil field in the middle North Sea; and the ...