Showing papers on "Photovoltaic thermal hybrid solar collector published in 1991"
TL;DR: In this paper, a hybrid system, which is a combination of an air heater and photovoltaic system is analyzed, and the optimum area of the solar cells necessary to generate sufficient electrical energy for the pump is calculated for different configurations of the air heater.
164 citations
Patent•
29 Nov 1991
TL;DR: In this paper, the input resistance of the direct current converter is adapted by a microcomputer to the maximum power point (MPP) of the solar generator, the MPP being dependent upon the solar insolation and the temperature of solar cells.
Abstract: An energy-generating plant including a solar generator, having solar cells, for producing electrical energy. The electrical energy is supplied to a direct current converter, the output power of which may be used to charge an energy storage system, such as batteries. The input resistance of the direct current converter is adapted, such as by a microcomputer, to the maximum power point (MPP) of the solar generator, the MPP being dependent upon the solar insolation and the temperature of the solar cells. At start up of the plant, or when there is a change of power at the output of the direct current converter, a search process is carried out to attain the MPP of the solar generator. The energy storage system may be used to energize an electric motor for driving the propeller of a ship.
91 citations
Book•
13 Dec 1991
TL;DR: The solar energy resource transmission through transparent materials absorption of solar energy at surfaces flat plate collectors line-axis concentrating collectors solar ponds solar dryers solar refrigeration greenhouses passive and active solar design of buildings as discussed by the authors.
Abstract: The solar energy resource transmission of solar energy through transparent materials absorption of solar energy at surfaces flat plate collectors line-axis concentrating collectors solar ponds solar dryers solar refrigeration greenhouses passive and active solar design of buildings.
70 citations
TL;DR: In this article, the authors presented a theoretical study of a solar photovoltaic-thermal (hybrid) system consisting of a flat-plate solar air heater mounted with solar cells and a plane booster.
59 citations
01 Jan 1991
TL;DR: In this paper, a cost-effective production technology for the manufacture of high efficiency laser-grooved buried grid (LGBG) crystalline silicon solar cells was developed and demonstrated 17% photovoltaic conversion efficiency on a new demonstration plant recently commissioned at BP Solar Espana in Madrid.
Abstract: BP Solar have developed a cost-effective production technology for the manufacture of high efficiency laser grooved buried grid (LGBG) crystalline silicon solar cells. The process has demonstrated 17–18% photovoltaic conversion efficiency on a new demonstration plant recently commissioned at BP Solar Espana in Madrid. This paper outlines the technology of cell fabrication and details the performance characteristics of the resulting cells and modules. With low cost polycrystalline substrates the technology is expected to lead to a significant reduction in the fabrication cost per Watt of silicon solar cells.
47 citations
TL;DR: In this paper, a new concept of integration of a solar concentrator field with a modern thermal power station is proposed, which would utilize the existing equipment and infrastructure as a base load facility and solar energy to reduce the fuel consumption during periods of insolation.
Abstract: A new concept of integration of a solar concentrator field with a modern thermal power station is proposed. Such a configuration would utilise the existing equipment and infrastructure as a base load facility and solar energy to reduce the fuel consumption during periods of insolation. The methodology suggested involves feed water heating using a solar concentrator field and consequent reduction of steam extraction presently used for the purpose. Study of retrofit to a 210-MW coal-fired plant indicates that saving of fuel upto 24·5% during periods of insolation can be achieved for feed water heating upto the present level, which is to a temperature of 241°C. The annual saving in coal would be around 47,000 tons at an estimated cost of about Rs. 3 crores. A doubling of the savings, by heating to a higher temperature level of 330°C, is feasible with presently available solar technology. Areas needing detailed study for achieving such an integration are indicated. The control system required to allow for fluctuations in the solar output is outlined. It is felt that the proposed system, where solar energy contributes a small but significant fraction of the total output of the plant, would be easier to control than one where the total energy is provided by solar radiation. A preliminary estimate indicates that the proposed system may cost about half of a stand-alone solar plant with back-up fuel and with the same solar input. However site-specific studies need to be carried out to confirm these figures.
29 citations
01 Jan 1991
TL;DR: In this paper, a buffering storage system is used to cope with diurnal, seasonal and weather-related insolation changes in a solar power plant during peak demand periods, where the solar plant input may be packed up by fossil fuels, or the solar changes may be mitigated by buffering.
Abstract: Like any other power plant, solar power plant (SPP) output must satisfy the demands of the utility market. During peak demand periods, kilomwatt-hour prices are high and financial incentives are high for guaranteed supply. Solar plant input is limited by diurnal, seasonal and weather-related insolation changes. In order to cope with these fluctuations, the solar plant input may be packed up by fossil fuels, or the solar changes may be mitigated by a buffering storage system.
28 citations
TL;DR: In this article, modified concrete for existing solar farm plants and refractory ceramics for proposed air cooled solar tower plants have the best prospects for near-term realization of large scale solar thermal energy storage systems.
26 citations
01 Jan 1991
TL;DR: In this article, basic concepts of the conversion of solax radiation for its use in the present day's energy economy are considered: to heat, to electric energy, to chemical energy carriers.
Abstract: Solar radiation incident upon the Earth is the primary energy source by which the life of mankind has developed. In this chapter basic concepts of the conversion of solax radiation for its use in the present day’s energy economy are considered: to heat, to electric energy, to chemical energy carriers. The emphasis will be on the upper limits of conversion yields, derived from laws of thermodynamics. Such upper limits expose the boundaries of how much can at most be achieved from incident solar radiation. They are a guidance to appreciation of what has already been realized in practice and what still is the potential for further development.
TL;DR: In this paper, the authors investigated the overall efficiency of solar thermal power plants for estimating the upper limit of their practical performances, which is the product of the efficiency of the solar collector and the energy efficiency of a heat engine.
Abstract: The overall efficiency of solar thermal power plants is investigated for estimating the upper limit of their practical performances. This study consists of the theoretical optimization of the heat engine and the optimization of the overall system efficiency, which is the product of the efficiency of the solar collector and the efficiency of the heat engine. In order to obtain a more realistic performance of the solar thermal power plant, the solar collector concentration ratio, the diffused solar radiation and the convective and radiative heat losses of the solar collector are taken into account. Instead of the classical Carnot efficiency, the efficiency at maximum power is used as the optimal conversion efficiency of a heat engine. By means of simple calculations, the optimal overall system efficiency and the corresponding operating conditions of the solar collector are obtained. The results of the present work provide an accurate guide to the performance estimation and the design of solar thermal power plants.
01 Jan 1991
TL;DR: In parallel with the increasing interest in solar power generation, several solar thermal facilities of different configuration and size were built, operated, and evaluated in the last decade and a half as discussed by the authors, some of which were exploratory, first-of-a-kind or demonstration nature, in some cases designed merely as engineering experiments for the purpose of gaining performance and operating data at the subsystem and overall plant level.
Abstract: In parallel with rising interest in solar power generation, several solar thermal facilities of different configuration and size were built, operated, and evaluated in the last decade and a half. Some of these facilities were of exploratory, first-of-a-kind or demonstration nature, in some cases designed merely as engineering experiments for the purpose of gaining performance and operating data at the subsystem and overall plant level. Most facilities were designed as modest-size experimental or prototype solar power plants (SPP) for producing electricity, in a few cases also for cogenerating thermal energy. Of all solar thermal technologies investigated, SPPs using parabolic trough concentrators were the first to reach sufficient maturity to be constructed on a commercial basis in a favorable regulatory environment. Table 7.1 provides an overview of the facilities built, their aggregate nominal capacity (MWe), and their total collective/reflective area.
TL;DR: In this paper, a performance study of a Rankine organic cycle powered by a flat plate solar collector is presented, where the heat transfer fluid is vaporized and its saturated vapor expands in a turbine according to the Rankine cycle and the collector system is divided into a boiling and a nonboiling (subcooled) part: the limit between the two depends upon the value of flow rate and radiation.
Abstract: In this paper a performance study is presented of a Rankine organic cycle powered by a low temperature flat plate solar collector. In this work a two-phase collector is considered where the heat transfer fluid is vaporized and its saturated vapor expands in a turbine according to a Rankine cycle. The collector system is divided into a boiling and a nonboiling (subcooled) part: The limit between the two depends upon the value of flow rate and radiation. A modified form of the Blish equation is used to model the thermal performance of the collector in terms of thermal efficiency versus DTI (DTI = (Absorber average temperature-Ambient temperature)/Solar Radiation). The system is analyzed by second-law analysis, and it includes several exergy losses of different types (heat transfer, heat loss, etc.) which determine the overall exergy balance. Different working fluids are considered, and optimization to a certain extend is demonstrated from this point of view. In order to minimize irreversibilities and guarantee the most efficient conversion processes, the most important point is the right selection of the collector operating pressure level, which depends on the instantaneous value of radiation and ambient temperature (as well as on the collector thermal performance). The choicemore » of the optimal pressure level is done by means of second-law arguments; the flow rates across the collector, the turbine, and the condenser are consequently determined. A simulation over a typical sunny day in Florence, Italy allows the calculation of the expected daily performance.« less
01 Jan 1991
TL;DR: In this paper, a detailed mathematical model simulating the thermal behavior of small low-flow solar heating systems has been developed and validated by means of indoor experiments with a mantle heat storage.
Abstract: Experiments have shown that small solar heating systems using low flow operation and a hot water tank with an enclosing mantle perform extremely well A detailed mathematical model simulating the thermal behaviour of such solar heating systems has been developed and validated by means of indoor experiments with a mantle heat storage The yearly thermal performance of different designs of and operation strategies for small low flow solar heating systems have been calculated By use of the model it is possible to optimize the design of the system, the operation and control strategy of the system The calculated thermal performance of the low flow system is compared to the calculated thermal performance of a traditional solar heating system using a normal flow rate The calculated increase of thermal performance of the low flow system is somewhat smaller than the measured increase of the thermal performance Therefore, work is still necessary in order to validate the developed model by means of experiments with a complete solar heating system
Patent•
18 Jan 1991
TL;DR: In this article, the multiple reflection solar energy absorber makes possible the direct absorption of solar energy into a transparent working fluid, thereby heating the fluid and discharging it through a nozzle to produce power.
Abstract: This invention the multiple reflection solar energy absorber makes possible the direct absorption of solar energy into a transparent working fluid, thereby heating the fluid and discharging it through a nozzle to produce power. The invention comprises a method for producing an ultra high concentration of solar flux and a means to circulate the working fluid into an interior cavity confining the ultra high energy concentration producing absorption of heat energy. The apparatus of the invention comprises a primary and a secondary solar energy concentrator, a multiple reflection chamber, a working fluid, a nozzle and thermal insulation. The invention can be constructed in several embodiments suitable for heating both liquids and gases.
01 Jan 1991
TL;DR: The second ASME-JSES-JSME international solar energy conference as discussed by the authors was organized under the following headings: Solar ponds, Energy fundamentals in solar systems, General solar energy, Solar powered cars, Distributed receiver components and systems, Central receiver components, Chemical processes and waste destruction, High flux and innovative applications, Solar thermal space propulsion, Solar dynamic power systems, Analysis methods for monitored building use.
Abstract: This book contains paper presented at the second ASME-JSES-JSME international solar energy conference. It is organized under the following headings: Solar ponds, Energy fundamentals in solar systems, General solar energy, Solar powered cars, Distributed receiver components and systems, Central receiver components and systems, Chemical processes and waste destruction, High flux and innovative applications, Solar thermal space propulsion, Solar dynamic power systems, Analysis methods for monitored building use. Photovoltaics, Testing and measurement.
TL;DR: The term solar thermal systems as mentioned in this paper is used to describe the use of solar radiation for a wide range of heating purposes at varying temperature levels, including photovoltaic effect to produce electricity or indirectly through the solar thermal electric conversion process.
TL;DR: In this article, the authors present a new and potentially highly efficient solar thermal to electric converter based on a solar sustained cesium plasma, which can be used to convert solar energy into useful forms.
Abstract: The efficiency with which solar energy can be converted into more useful forms is one of the most important parameters concerning its utilization as a viable alternate source of energy. High efficiencies can be obtained by utilizing higher temperature working fluids. This in turn implies concentrating the intensity of sunlight using focussing type collectors. A review of the history of solar energy conversion and the types of collectors, particularly those which use concentrating techniques, is presented. The amount of solar energy available for focussing type collector systems is discussed. Potential applications of concentrated solar intensity are presented in this article. A description of a new and potentially highly efficient solar thermal to electric converter based on a solar sustained cesium plasma is presented. Photovoltaics are not discussed in any detail in this article.
TL;DR: In this article, the authors investigated the sensitivity of PV hydrogen production costs to changes in the system parameters and identified key conditions for low-cost PV hydrogen synthesis in the Southwestern U.S.
01 Jan 1991
TL;DR: In this article, an examination of a RTVP conceptual design has shown a high potential for power densities well above those achievable with radioisotopic thermoelectric generator (RTG) systems.
Abstract: An examination of a RTVP (radioisotopic thermophotovoltaic) conceptual design has shown a high potential for power densities well above those achievable with radioisotopic thermoelectric generator (RTG) systems. An efficiency of 14.4 percent and system specific power of 9.25 watts/kg were predicted for a system with sixteen GPHS (general purpose heat source) sources operating at 1100 C. The models also showed a 500 watt system power by the strontium-90 isotope at 1200 C at an efficiency of 17.0 percent and a system specific power of 11.8 watts/kg. The key to this level of performance is a high-quality photovoltaic cell with narrow bandgap and a reflective rear contact. Recent work at Boeing on GaSb cells and transparent back GaAs cells indicate that such a cell is well within reach.
Patent•
24 Jan 1991
TL;DR: In this paper, a photovoltaic collector is used to cover the IR absorbing material of a thermic collector with the heat exchanger pipes embedded in a super insulating acrogel.
Abstract: The solar collector utilising the energy of the sun for providing heating has a heat exchanger supplied with a heat exchange medium for acting as a thermic collector (1), the latter combined with a photovoltaic collector (2). Pref the thermic collector (1) is transparent to visible and/or UV radiation, with the photovoltaic collector (2) lying behind it in the propagation direction of the incident radiation. Pref. IR absorbing material is used for the thermic collector with the heat exchanger pipes embedded in a super insulating acrogel. USE - For simultaneous provision of heat and electrical energy.
01 Jan 1991
TL;DR: In this paper, various aspects of photoelectrochemical utilization of solar energy and the progress in this field during the last couple of years are discussed and discussed in the present paper.
Abstract: In the present paper various aspects of photoelectrochemical utilization of solar energy and the progress in this field during the last couple of years are discussed
Patent•
15 Mar 1991
TL;DR: In this article, a solar energy conversion system has mirrors (2,3) that select different solar energy spectra, and each stage has a heat sink (7,8,9) so that the temp of a fluid reduces (T1,T2,T3).
Abstract: A solar energy conversion system has mirrors (2,3) that select different solar energy spectra. Low band energy is selected by a first stage (4) with successive stages handling medium and high band energy levels (5,6). Each stage has a heat sink (7,8,9) so that the temp. of a fluid reduces (T1,T2,T3). An alternative version has a tandem solar cell arrangement in which stages are stacked with input from a common cell. A further version has different band energy stages arranged in sequence on a pipe.
01 Jan 1991
TL;DR: In this article, a review of thin-film amorphous and polycrystalline photovoltaic cells with a view to potential applications in space is presented, and two important figures of merit are discussed: efficiency (i.e., what fraction of the incident solar energy is converted to electricity), and specific power (power to weight ratio).
Abstract: Developments in thin-film amorphous and polycrystalline photovoltaic cells are reviewed and discussed with a view to potential applications in space. Two important figures of merit are discussed: efficiency (i.e., what fraction of the incident solar energy is converted to electricity), and specific power (power to weight ratio).
Proceedings Article•
01 Jan 1991
TL;DR: The latest design, fabrication and testing details of a prototype wing are discussed in this article, where estimates of array-level performance are presented as a function of power level and solar cell technology for geosynchronous orbit (GEO) missions and solar electric propulsion missions through the Van Allen radiation belts.
Abstract: The latest design, fabrication and testing details of a prototype wing are discussed Estimates of array-level performance are presented as a function of power level and solar cell technology for geosynchronous orbit (GEO) missions and solar electric propulsion missions through the Van Allen radiation belts Design concepts are discussed that would allow the wing to be self-retractable and restowable To date all testing has verified the feasibility and mechanical/electrical integrity of the baseline design The beginning-of-life (BOL) specific power estimate for a nominal 10-kW (BOL) array is about 138 W/kg, with corresponding end-of-life (EOL) performance of about 93 W/kg for a 10-year GEO mission
TL;DR: In this paper, a parametric investigation of solar pond design and operational characteristics to the capacity of a conventionally designed, commercially available, absorption chiller is presented, which can be used for the rough design and pond size selection for operation of chillers of a substantial capacity, directly from solar ponds.