Showing papers on "Solar power published in 1981"

Solar power module

Abstract: A solar power module comprising an array of solar cells arranged on a flat panel, said panel being supported by a substantially rigid, easily assembled frame comprising spaced apart side channels that each interlock with adjacent and channels.

Optimum Operation of a Combined System of a Solar Cell Array and a DC Motor

Abstract: The increased use of solar electrical (photovoltaic) systems, especially solar power packs for water pumpting, etc., brings about the need for a new approach for analysis and design. In this paper a new method for optimum matching of an electric motor, with a varying mechanical load, to a solar cell array (SCA), is presented. This method enables, by means of switching procedures of the SCA together with flux changes, to assure maximum mechanical energy supply to the load. Moreover, the use of the DCT enables to overcome the problem of the relatively large starting currents of the motor.

Solar power station having groups of solar collectors

Abstract: A solar power station comprising two groups of solar collectors joined together to form an annular platform which floats on a body of water. Each of the collectors of one group has a solar absorbing layer which is in thermal communication with heat carrier fluid ducts and a plurality of spaced upstanding walls are included on an upper surface of the solar absorbing layer. Each of the collectors of the second group includes means for concentrating solar radiation onto ducts carrying a heat carrier fluid. Heat storage areas submerged in water are thermally connected to the groups of collectors and are positioned beneath the platform. Means are provided for rotating the platform so that the spaced parallel walls remain parallel to sun rays throughout the day.

Solar power satellite

Abstract: A solar power satellite (30) includes a truss structure (32) having a plurality of independently controlled solar power modules (34) mounted to one face of the truss structure. The solar power satellite is constructed in orbit by first forming and then assemblying component beam members (50, 52) to the truss structure. The solar power modules (34) are constructed on a fabrication and assembly station (36) movably attached to the truss structure and are then attached to the truss structure. The solar power modules (34) include a primary reflector (200) having a substantially parabolic curvature in cross section. A collector-radiator (202) is mounted on the primary axis of the primary reflector. The cross-sectional configuration of the collector-radiator (202) approximates a flattened inverted S-shape whereon the radius of curvature decreases as the curve approaches both its center and its end furthermost from the primary reflector (200). The primary reflector (200) is contoured to reflect sun light onto the collector-radiator structure (202). The collector-radiator structure includes a plurality of spaced radiant energy converting cells (450 ). A plurality of light reflective fins (452) are positioned between the converter cells. Each fin is thermally and electrically connected to converter cells on each side thereof. The fins provide radiant cooling of and series electrical connection between the converter cells. The fins also serve as a secondary reflector for concentrating sun light from the primary reflector onto the converter cells.

Optimization of Liquid Desiccant Systems for Solar/Geothermal Dehumidification and Cooling

Abstract: Two efficient design configurations of a liquid desiccant cooling/dehumidification system that can be powered by low grade solar or geothermal energy and promise low parasitic power requirements for blowers and pumps are proposed and analyzed in this work. A mathematical model for each component in this system has been developed and synthesized for system simulation. The system performance is predicted and optimized through parametric studies using the computer code LIQSYS. It is shown that the exhaust recirculation mode (ERM) gives better performance at full capacity while the process recirculation mode (PRM) produces cooler and drier air.

Solar power station with photovoltaic cells

Abstract: A solar power station, in particular of a relatively small size, for generating both electricity and useful heat. Photovoltaic cells (34) are fitted to a hollow holder (33) bearing a flow of cooling fluid. That part of the light spectrum which can be converted into electricity by the photovoltaic cells only at a low efficiency or not at all is filtered out by tubular glass bodies (31, 32), so that the heat loading on the photovoltaic cells is reduced. In the annular space between the glass tubes (31), the cooling fluid preheated in the interior of the holder (33) circulates and is further heated here by its own heat absorption and the removal of the heat absorbed in the glass bodies (31, 32). This cooling fluid can be used for heating purposes. The glass bodies (31 and 32) can be made of glasses of different types, which absorb light in the lower or upper part of the spectrum respectively.

Optimal Control of Mass Flow Rates in Flat Plate Solar Collectors

Abstract: The optimal flat plate collector fluid flow rate is determined for several combinations of objective functions and system models. The method of implementing the control strategy for one of the problems considered, that which maximizes the integral of the difference between the collected solar power and fluid moving power, is described. The performance of the solar energy collection system in Solar House II at Colorado State University using this optimal controller is discussed and compared with the same system using bang-bang control. In addition, the dependence of the collector efficiency factor on flow rate is considered and its effect on the optimal control is determined.

Solar power generating device

Abstract: PURPOSE:To inexpensively manufacture a solar generating device having high light collecting efficiency by forming a formed liquid lens. CONSTITUTION:A formed water lens 11 is formed of flat light transmission member 11b formed of glass or resin having a water channel 11c confronting a plurality of light incident members 11a. On the other hand, a plurality of solar cells 3 are placed on a solar cell support 14 so as to be disposed at the focuses of the water lenses. Thus, the similar light collecting efficiency to the optical convex lens can be carried out with the members 11a and water having approximately equal light refractive index to that of the members 11a, and can also be formed remarkably inexpensively. When the solar light rays 6 collected via the water lenses pass the water, a part of the heat ray energy of the solar light rays is absorbed to the water 16 to convert the energy, and accordingly the solar cells 3 can be protected against the high temperature damage.

NASA Redox system development project status

Abstract: NASA-Redox energy storage systems developed for solar power applications and utility load leveling applications are discussed. The major objective of the project is to establish the technology readiness of Redox energy storage for transfer to industry for product development and commercialization by industry. The approach is to competitively contract to design, build, and test Redox systems progressively from preprototype to prototype multi-kW and megawatt systems and conduct supporting technology advancement tasks. The Redox electrode and membrane are fully adequate for multi-kW solar related applications and the viability of the Redox system technology as demonstrated for multi-kW solar related applications. The status of the NASA Redox Storage System Project is described along with the goals and objectives of the project elements.

Power/energy: Reflector satellites for solar power: Solar-cell arrays in arid zones plus microwave transmission to space and back can send power where needed

Abstract: Solar-cell arrays in arid zones plus microwave transmission to space and back can send power where needed. A three-stage development project is suggested which could be carried out within 20 years.

Turbomachinery for small solar power plants

Abstract: Conversion of solar energy into mechanical or electrical energy in small solar power plants (10–500 kW) requires new design criteria, especially with regard to turbomachinary. The cycles suitable for solar power production are affected by many variable such as kinds of working fluid, range of power and maximum cycle temperature determined by the type of collector. Also, the size of the plant will influence the selection of the various components of the plant, especially that of the turbomachinery. A study of a suitable thermodynamic cycle and working fluid is done for different ranges of power and temperature. The working fluids considered are steam, toluene, and refrigerant 113 for the Rankine cycle systems and air for gas turbine systems. For Rankine cycles, turbine selection is a problem in the small power range. This is mainly due to the fact, that for high efficiency the enthalpy drop should be as high as possible, and the mass flow rate of the working fluid through the turbine becomes very small. This, in turn, requires high rotational speed, multistaging and partial admission, especially if water is the working fluid. Toluene offers better design criteria for the turbine in the same temperature and power range (50–200 kW). For the very small range (10 kW) refrigerant 113 or similar should be used, otherwise severe design problems with the turbine will occur. In this power range, photovoltaics may also be considered. For high concentration systems with “Brayton cycles” (800–1000°C) only open-cycle gas turbine plants should be used.

High-Flux Solar Absorber Concept for Central Receiver Power Plants

Abstract: For cylindrical receivers with a capacity of about 400 MW/t, an aim-at-the-belt focusing strategy can produce average fluxes the order of 0.5 MW/m2 with peaks as high as 2 MW/m2 . An absorber concept is described which uses liquid sodium coolant and a three-header configuration to efficiently capture this solar power. The mechanical design of this absorber is discussed and thermal performance estimates are presented showing the solar-capture efficiency over a range of solar intensities. The sodium-flow characteristics and some potential flow-control problems are also described. A thermal-stress analysis is presented which shows that a limiting factor on the flux capability may be tube-wall creep/fatigue failure and not the heat-transfer capability of sodium.

A simplified model of the thermohydraulic behaviour of a linear collector network for the conversion of the solar energy

Abstract: A model has been set up to describe the thermohydraulic behaviour of a solar power plant in a quasi-steady-state approach; the simplifying assumptions have been proved to be correct. The model has been solved to determine the optimum sizes of the thermal accumulator.

A very wide area thin film solar cell fabricated by molecular beam epitaxy in space

Abstract: A concept of cumulative solar photovoltaic power generation system utilizing a solar powered thin film solar cell fabrication process in space has been proposed Principal mechanism of the electric power multiplication system might be analogous to the biological production system in a living thing which grows by a continuous energy supply from the sun Specialities of the space environments, particularly, steady with high solar energy density, ultrahigh vacuum and microgravity are fully utilized for the thin film solar cell production and the cumulative photovoltaic power generation Technological and material science considerations for the development of a very wide area thin film solar cells by a molecular graphoepitaxial growth in space have been made A feasibility study for the new system has also been made with reference of the previously reported satellite solar power station system The result shows that the proposed system might work much economically rather than the present space transportation plan for the satellite solar power station, and provides large amount of potential energy demands both for space missions and terrestrial energy resources in the future

Solar power booster for domestic heating - has fresh air heated by combination of heat in exhaust air and solar energy

Abstract: The building has a sun trap (1) built onto the south side. This can be arranged to form an additional room such as a conservatory. Vitiated air extracted (6) from other rooms passes through a header (8) to a heat exchanger (5) from which it is exhausted (10) to atmosphere. There is a bypass (11) round the heat exchanger to control the heat transfer. Fresh air (15) is drawn through the heat exchanger (5) to a valve box (18). From the valve box it can be delivered either directly (29) to the rooms or through the conservatory (20,21) in which it gains further heat from the solar energy trapped by the glass walls.

Energy storage in aquifers

Abstract: Economic and engineering evaluations of energy-storage potential in certain USA aquifers are being conducted Particularly detailed evaluations have been made for compressed air energy storage (CAES), using off-peak power from nearby nuclear power stations In current studies, we are examining thermal energy storage and utilization prospects, using solar power or, alternatively, off-peak, low-cost nuclear power as the heat source Economic and energy-saving aspects of selected combinations of sources, storage media, and uses are ranked with respect to various selection criteria

Influence of environmental conditions and architectural form on the design and thermal performance of the flat-plate solar collector system.

Abstract: Solar heating systems, by the nature of their design and inherent thermal mass, are sensitive to the changes in the prevailing climatic conditions A computer program has been developed to predict and display the dynamic performance of solar water heating systems and their installation designs under transient climatic and restricted site conditions A multi-node capacitance model describes the dynamic heat transfer and energy storage processes within the solar collector unit, storage tank and the connecting pipework This simulation model predicts the dynamic system performance under intermittent solar radiation, system operation and energy usage conditions Validation studies have been carried out on the computer simulation results against the performance of a purpose-built solar collector test facility and a commercial solar water heating system in actual operation in Aberdeen A good correlation has been obtained in both cases The accuracy of the prediction was found to be dependant upon the time interval of the available climatic data and the complexity of the thermal simulation network chosen The experimental facilities and the computer simulation program have been developed to investigate the effect of integrating the solar collector installation as part of the roof fabric, as a possible technique to improve the system performance in exposed locations The application of this computer program lies in the development of innovative solar collector system and installation designs to achieve optimum system performance under transient climatic and restricted urban site conditions

Solar Power Stations for Remote Sites: An Economic Analysis.

Abstract: : While solar power plants are not presently economically competitive with fossil fuel power plants at most locations, solar power may be competitive at some remote locations. Energy at remote locations is both costly and subject to disruptions due to hostilities and/or shortages of fuel. Even if the direct costs of fossil fuel power plants are not sufficient to make solar power economically attractive the costs associated with fuel supply disruptions (or the possibility of disruptions) may make solar power desirable. Evaluation of the economic and strategic feasibility of utilizing solar power can be accomplished by comparing the uniform annual costs of competing systems over their lifetimes. Formulas are developed for fossil fuel and solar power plants to enable economic evaluation of the costs of competing power plants. Evaluation can be accomplished whether the present power plant requires replacement, or if it is desired to reduce use of, and dependence on, fossil fuels even though the present power plant is still serviceable. An example shows that solar derived energy may be economically feasible, depending on the cost data and assumptions used for a study. (Author)

Experimental simulation of latent heat thermal energy storage and heat pipe thermal transport for dish concentrator solar receiver

Abstract: The effective utilization of a focus mounted parabolic dish Stirling solar power conversion unit is favored by the use of heat pipe thermal transport and latent heat thermal energy storage (TES). Such a system has been designed and is being fabricated for test. A modular simulation of the thermal transport and storage of this system has been tested at different operating angles, power levels and time periods appropriate to that design. 7 refs.

Lead-acid standby-power batteries in telecommunication — ‘horses for courses’

Abstract: A review is made of the battery applications in the Telecommunications Industry and of the various types of lead acid battery currently in use. Network Switching applications use all the three basic types of lead acid battery (Plante, Tubular and Pasted Plate) and this situation is accounted for in terms of the mutual development of the system and its battery in close co-operation between user and manufacturer. Performance selective applications such as Engine Starting and Uninterrupted Power Supplies requiring fast rates of discharge are discussed and a case is made out, in certain circumstances, for selecting the Plante cell for the optimum battery system. Design selective applications are discussed and the Tubular cell battery is identified as the natural choice for Maritime Installations (Oil Rigs) and cells with large electrolyte reserves to be used in batteries for Solar Power systems. Trends for the future of lead acid batteries are considered and this is related to the need for International Standardisation.

Solar heating and cooling of buildings

Abstract: Some background is presented regarding the sun, solar energy, the solar spectrum and atmospheric attenuation of sunlight. Some geometry relevant to solar application is covered briefly. Some basic principles of solar collectors and basic designs and considerations of passive and active collection are given. Practical aspects are examined including heat requirements, design and performance of collectors, heat storage, criteria for selecting a system, obtaining legal permission and financing to install the system, and advice on installing and operating the system. In terms of 1976 dollars, costs are broken down for solar water heating systems, water and space heating systems using water and using air for heat transfer, heating, cooling and hot water systems, and solar assisted heat pumps. Optimization and life-cycle costing are thoroughly covered. The net cash flow resulting from using one solar hot water system is computed from a model using fuel savings, tax savings, maintenance and insurance costs, property tax, and loan payments, year by year over 20 years. Six examples of solar energy systems are examined. Some economic, environmental, and political benefits to the US resulting from large scale solar power use are listed, and Federal programs advancing solar power are described. State and local efforts more » are briefly mentioned. Incentives and barriers to commercialization of solar heating and cooling are discussed. Environmental and safety aspects are examined. Future financial incentives, new systems, and marketing projections are discussed. Nine useful appendices are included which cover: solar legislation state by state; state energy offices; manufacturers; tables listing sources of help on installation; some currently used simulation programs; the future in terms of market penetration; simply computed life-cycle costs; projection of savings; and technology and market assessment studies. (LEW) « less