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Showing papers on "Photovoltaic thermal hybrid solar collector published in 1986"


Journal ArticleDOI
TL;DR: In this paper, a hybrid amorphous silicon photovoltaic and thermal solar collector was developed and its performance tested, and the results obtained show that it is possible to construct simple and cheap hybrid systems having good photiovoltaic as well as thermal efficiencies.

128 citations


Journal ArticleDOI
TL;DR: For greenhouse heating with solar energy, different techniques can be used: separate solar collectors, solar collectors integrated in the greenhouse, and the use of the greenhouse itself as a solar collector as mentioned in this paper.

54 citations


Journal ArticleDOI
TL;DR: In this paper, a theoretical analysis of the solar photovoltaic and thermal (PVT) collector using a simulation model is presented, where the collector is divided into a matrix of small PVT collector units, each one consisting of several layers.
Abstract: The solar photovoltaic and thermal (PVT) collector is a device which converts solar energy into thermal and electrical energies simultaneously. The PVT collector can be used whenever both electricity and hot water are required, for example, for domestic uses. It is a known fact that the efficiency of the solar (photovoltaic) cells decreases as operating temperatures increase. Therefore, a better and a more efficient use of these cells, calls for cooling the cells. One method for doing that is to use a heat exchange system, which cools the cells by means of a heat absorbing medium, such as water, flowing in pipes. The heat removed from the cells results in hot water. Another advantage of the PVT collector is its higher overall efficiency per unit area and lower packaging costs due to its compact design. In this paper a theoretical analysis of the PVT collector using a simulation model is presented. In this model the PVT collector is divided into a matrix of ``small'' PVT collector units, each one consisting of several layers. The energy balance of each ``small'' PVT collector unit is studied by analysis of the energies entering and leaving each one of its layers. Later, the process is applied to the PVT collector itself. A PVT collector was designed and constructed and putthru a series of experiments under varying load conditions, insolation levels and other climatological conditions.

34 citations



Patent
29 Dec 1986
TL;DR: A self-contained, solar powered unit predominately used for watering livestock is described in this paper, where the preferred embodiment of the unit is an integrated combination which utilizes a solar collecting panel to generate electricity for powering a fluid pump that pumps fluid into a reservoir tank.
Abstract: A self-contained, solar powered unit predominately used for watering livestock Fundamentally, the preferred embodiment of the unit is an integrated combination which utilizes a solar collecting panel to generate electricity for powering a fluid pump that pumps fluid into a reservoir tank The reservoir tank, further, supplies fluid to an adjoined watering trough for access by livestock The unit is simple, compact, and thus, highly portable while its operation is economical and requires little maintenance

19 citations


ReportDOI
01 Oct 1986
TL;DR: In this article, several candidates from a broad class of ceramic materials were evaluated for possible application as a solid thermal transfer medium in a high temperature solid particle solar receiver, and the suppliers of the materials, the materials' characteristics, and comments regarding the suitability of each of them for the transfer media were provided.
Abstract: Several candidates from a broad class of ceramic materials were evaluated for possible application as a solid thermal transfer medium in a high temperature solid particle solar receiver. This report documents the suppliers of the materials, the materials' characteristics, and comments regarding the suitability of each of the materials for solid thermal transfer media.

19 citations


Journal ArticleDOI
TL;DR: In this paper, a latent thermal storage unit using form-stable high-density polyethylene (HDPE) was proposed for a waste heat recovery system with three solar thermal application systems.
Abstract: Conceptual designs and cost evaluations were made for three solar thermal application systems and a waste heat recovery system with a latent thermal storage unit using form-stable high-density polyethylene. A detailed design of the storage unit shows that it is economically competitive with other thermal energy storage devices such as the steam accumulator. The solar air conditioning system and the waste heat recovery system with this storage unit are feasible. On the other hand, the solar thermal power generation systems with collectors of non-tracking and nonconcentrating type are not cost-effective, mainly due to low conversion efficiency arising from the low operating temperature. System simulations of the two promising systems were carried out.

18 citations


01 Feb 1986
TL;DR: In this article, a conceptual design of a solid particle central receiver is presented for high-temperature (greater than 550/sup 0/C) applications of solar energy.
Abstract: Solar central receiver systems utilize mirrors to reflect and focus the sunlight onto a receiver that resides on top of a centrally located tower. By redirecting the sunlight in this manner, the solar flux at the receiver surface can be equivalent to hundreds of suns. A working fluid in the receiver is heated by absorbing the solar radiation. This fluid can then be used to produce electricity or incorporated into products as process heat. Currently, the working fluids in a solar central receiver are gases or liquids that flow through tubes heated by the solar radiation. An example of such a system is the water/steam central receiver system located near Barstow, California, which produces electrical energy. Other common working fluids include molten salts, molten metals, and air. A novel concept for a central receiver currently being examined employs sand-size refractory particles that freefall in a cavity receiver. A conceptual design of a solid particle receiver is shown. The solid particle central receiver is being evaluated for high-temperature (greater than 550/sup 0/C) applications of solar energy. The advantages of a solid particle receiver over traditional fluid-in-tube receivers are: 1) the particles can directly absorb solar radiation and 2) the particles maintainmore » their integrity at high temperatures. These advantages, coupled with the possibility that the particles can serve as the storage medium, could provide a cost-effective means of high-temperature solar energy utilization. High temperatures are attractive for fuels and chemicals production, industrial process heat applications, or Brayton cycle electricity generation.« less

18 citations




Journal ArticleDOI
TL;DR: In this paper, the optimization of the performance of a plant consisting of a solar photovoltaic converter and a water electrolyzer has been theoretically analyzed, and it is shown that the criterion of the maximum productivity of the plant coincides with that of the operation of the solar array at the point of maximum power.

Journal ArticleDOI
TL;DR: In this paper, the flat-plate solar collector is utilized as the desorber where water from the solution is evaporated to ambient air in passing over the collector above the solution film.
Abstract: This Paper presents a new continous operating solar desiccant absorption system in which CaCl 2 -H 2 O is used as the absorbent. The flat-plate solar collector is utilized as the desorber where water from the solution is evaporated to ambient air in passing over the collector above the solution film. The plant is equipped with a latent heat accumulation system which is extremely compact in size and very efficient. The coefficient of performance—solar collector efficiency product, indicating the grade of solar energy utilized, is estimated as being the highest of all presently known systems.

Patent
06 Oct 1986
TL;DR: In this paper, an improved solar water heating and storage system is described by use of physically separated yet thermally interfaced solar collector and domestic water storage reservoirs, which are designed to provide a thermal stacking effect of the solar fluid transfer medium and the domestic water supply to maximize system efficiency.
Abstract: An improved solar water heating and storage system is disclosed characterized by use of physically separated yet thermally interfaced solar collector and domestic water storage reservoirs. The reservoirs and conduit systems are designed to provide a thermal stacking effect of the solar fluid transfer medium and the domestic water supply to maximize system efficiency.

Journal ArticleDOI
TL;DR: In this paper, the authors derived the net efficiency of a solar cell as a product of two different efficiencies associated with the energy absorption and energy conversion into useful work, and the maximum net efficiency was obtained at room temperature.
Abstract: Assuming that both source and energy converters are blackbodies and applying thermodynamic balance equations, the net efficiency of a solar cell is derived as a product of two different efficiencies associated, respectively, with the energy absorption and energy conversion into useful work. At room temperature the maximum net efficiency thus obtained is 38%. Efficiencies are calculated at various solar cell temperatures, and results are discussed in view of existing theories.

Journal ArticleDOI
Shoichi Nakano1, Y. Kuwano1, M. Ohnishi1
TL;DR: In this paper, the super chamber, a separated UHV reaction-chamber system, was developed for an a-Si solar cell using a high-quality i-layer deposited by the super chamber, and a p-layer fabricated by a photo-CVD method.
Abstract: The super chamber, a separated UHV reaction-chamber system has been developed. A conversion efficiency of 11.7% was obtained for an a-Si solar cell using a high-quality i-layer deposited by the super chamber, and a p-layer fabricated by a photo-CVD method.

Journal ArticleDOI
TL;DR: In this article, the authors developed a model to examine the interaction of solar radiation with systems consisting of semi-transparent plates, and the model considered both beam and diffuse solar energy entering a system, as well as the conversion of beam to diffuse energy that may occur in some plates.
Abstract: The objective of this study is to develop a model to examine the interaction of solar radiation with systems consisting of semi-transparent plates. The embedding technique is developed so that the model considers both beam and diffuse solar energy entering a system, as well as the conversion of beam to diffuse energy that may occur in some plates. The fraction of the incident radiant energy absorbed by each plate is determined as well as the energy reflected and transmitted by the system. Results are presented to illustrate the absorptances for systems composed of such devices as glass panes and slat-type shades.


Book ChapterDOI
01 Jan 1986
TL;DR: A hybrid photovoltaic/thermal solar module that produces both electricity and hot water at the same time has been developed by SunWatt Corporation and has been in use in the field for the past two years as mentioned in this paper.
Abstract: A hybrid photovoltaic/thermal solar module that produces both electricity and hot water at the same time has been developed by SunWatt Corporation and has been in use in the field for the past two years. Experience gained during that time has indicated that the device is a reliable source of low voltage electricity; the 2 to 1 concentration ratio reflectors produce the expected increase in short circuit current on a year round basis without any seasonal adjustment. The thermal performance is similar to that of a conventional solar water heater with some loss of efficiency in cloudy weather. Failure of some of the early units under stagnation temperature conditions has been eliminated by changes in the encapsulation.

Patent
15 Oct 1986
TL;DR: In this article, the authors describe a collector of thermal energy, particularly solar energy, with composite structure, the elements of which are laid on the site of use to obtain a collector with a continuous surface of any dimension.
Abstract: The invention refers to a collector of thermal energy - particularly solar energy - with composite structure, the elements of which are laid on the site of use to obtain a collector with a continuous surface of any dimension. The structure of the collector comprises four layers, the first of which, positioned towards the source of thermal energy, is formed of a black rubber with high roughness and waterproof, which also has high characteristics of absorbing the radiations coming from the source; the second is a concrete layer, into which is buried a system of tubes through which flows a heat exchange fluid; the third is a layer of reflecting material, and the fourth is a layer of insulating material. The collector is used as a roofing for buildings or a coverage for other surfaces, it is practicable by pedestrians and motor vehicles and it is totally waterproof.



30 Apr 1986
TL;DR: In this paper, concept studies have been completed for four dish-Stirling receivers, i.e., solar only and thermal storage receiver, each of which is either directly coupled or indirectly coupled to the Stirling engine.
Abstract: Concept studies have been completed for four dish-Stirling receivers, ie, solar only and thermal storage receiver, each of which is either directly coupled or indirectly (heat pipe) coupled to the Stirling engine The results of these studies are to be applied to systems benefit/cost analysis to determine the most desirable development approach

Journal Article
TL;DR: In this paper, the behavior of a solar collector with a boiling fluid is analyzed to provide a simple algebraic model for future systems simulations, and to provide guidance for testing, and the efficiency equation is developed in a form linear in the difference between inlet and saturation (boiling) temperatures.
Abstract: The behavior of a solar collector with a boiling fluid is analyzed to provide a simple algebraic model for future systems simulations, and to provide guidance for testing. The efficiency equation is developed in a form linear in the difference between inlet and saturation (boiling) temperatures, whereas the expression upon which ASHRAE Standard 109P is based utilizes the difference between inlet and ambient temperatures. The coefficient of the revised linear term is a weak function of collector parameters, weather, and subcooling of the working fluid. For a glazed flat-plate collector with metal absorber, the coefficient is effectively constant. Therefore, testing at multiple values of insolation and subcooling, as specified by ASHRAE 109P, should not be necessary for most collectors. The influences of collector properties and operating conditions on efficiency are examined.

Journal ArticleDOI
TL;DR: In this paper, basic parameters for the determination of the conversion efficiency as well as the energy loss of solar cells are described, and different methods for solar cell calibrations are presented.

Journal ArticleDOI
TL;DR: In this paper, it is suggested that solar energy could become a more economical power source through the use of techniques which concentrate the maximum amount of light onto photovoltaic cells.
Abstract: It is suggested that solar energy could become a more economical power source through the use of techniques which concentrate the maximum amount of light onto photovoltaic cells. Limits of concentration are discussed and the design of practical 3D concentrations is considered

Proceedings ArticleDOI
24 Sep 1986
TL;DR: In this paper, the authors demonstrate how the application of passive heat dissipation technologies can significantly improve the photovoltaic efficiency of solar cell panels and demonstrate how such methods can be used to reduce solar cell panel temperatures.
Abstract: Current materials technology provides methods for reducing solar cell panel temperatures aboard spacecraft by passive heat dissipation technicues. Technology is available for the replacement of conventional solar cell panel substrates with materials which combine the advantages of lighter weight, improved structural strength, and increased thermal conductivity. This study demonstrates how the application of such methods can significantly improve the photovoltaic efficiency of solar cell panels.

Book ChapterDOI
01 Jan 1986
TL;DR: In this article, a solar collector system based on the Spherical Reflector/Tracking Absorber (SRTA) principle was proposed for heating liquid metals to intermediate temperatures.
Abstract: This paper describes a solar collector system, based on the Spherical Reflector/Tracking Absorber (SRTA) principle, for heating of liquid metals to intermediate temperatures. Liquid metals can serve as an excellent heat transfer fluid for some process heat applications, and can be used in an MHD generator, for which the present set-up was designed and tested. The paper describes the design, construction and testing of the system with a 2.5 meter diameter mirror aperture. The unit was tested under steady state conditions, yielding efficiencies between 25% and 35% (based on direct radiation). Efficiency variations with the solar input and operating temperatures are presented. Practical aspects related to the design of solar systems with liquid metals are discussed.

Journal ArticleDOI
TL;DR: In this article, the concept of cumulative solar photovoltaic power generation system in space has been proposed utilizing a solar powered thin film solar cell fabrication process, which might enable us to produce very wide-area high efficiency heteroface solar cells in space.

Journal Article
TL;DR: In this article, a solar cell concentrator system using a GaAs solar cell was constructed using a heat pipe, heat was transferred to a radiator, and the observed efficiency was 18.18.
Abstract: : If solar cells are exposed to charged particle radiation, efficiency decreases. Also solar cell efficiency is increased by concentrated solar light. A solar cell concentrator system includes shielding against particle radiation and provides concentrated solar light, with increased efficiency. A solar cell concentrator system was constructed using a GaAs solar cell. Using a heat pipe, heat was transferred to a radiator. Cell operating temperature (77 C) and under concentrated solar light (Concentration Ration = or approx. 130) solar cell efficiency was measured. Observed efficiency was 18.18. + or - 0.18 (%). These results were used to calculate the performance of an array, consisting of small concentrators. The performance of the concentrator array was compared with a conventional array, and demonstrated the higher efficiency advantages.

Journal ArticleDOI
TL;DR: In this article, the performance and the use of air solar heaters built in large single-unit surfaces and inserted in building structures have been investigated; the calculation procedure for predicting the behaviour of many types of conventional collectors is described; the characteristics and the results of some experimental models are indicated.
Abstract: For several years the performance and the use of air solar heaters built in large single-unit surfaces and inserted in building structures have been investigated. The calculation procedure for predicting the behaviour of many types of conventional collectors is described; the characteristics and the results of some experimental models are indicated. The fundamental equations regulating the thermal balance in the collector are shown together with the corresponding graphical representation. The criteria suggesting the introduction of air heaters directly into the building structures are discussed. Finally we give the description of some working plants: 1) a single-unit collector for the Civiglio school space heating; 2) a solar facade for heating the gymnasium in Moscoro; 3) a solar roof for hay drying in Tavazzano.