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Showing papers on "Solar energy published in 1979"


Journal ArticleDOI
TL;DR: In this article, the general principles and limitations of converting solar energy via photochemical reactions to electrical or chemical energy are described, and photosynthesis is concluded to be the only reliable and efficient system, suggesting that research efforts should aim at mimicking the photosynthesis process and modifying it to produce other fuel sources, such as hydrogen or ammonia.
Abstract: The general principles and limitations of converting solar energy via photochemical reactions to electrical or chemical energy are described Photosynthesis is concluded to be the only reliable and efficient system, suggesting that research efforts should aim at mimicking the photosynthesis process and modifying it to produce other fuel sources, such as hydrogen or ammonia, or developing artificial photochemical systems Few economic studies are available because the field is still too new and few systems show a reasonable degree of efficiency or longevity Early work indicates that a simple hybrid system able to operate as a single unit may have the most economic feasibility Economic assessments, however, should wait until scientific feasibility is established 190 references

484 citations


Journal ArticleDOI
TL;DR: The use of daily rather than hourly time intervals in the calculation of the monthly mean values of solar radiation for both horizontal and inclined surfaces has for long been a desirable objective due to a reduction in the required computational effort and more general availability of daily data as discussed by the authors.

475 citations


Journal ArticleDOI
TL;DR: Techniques and calculations are presented that give explicit expressions for the over-all performance of a luminescent solar concentrator in terms of the intrinsic spectral response and quantum efficiency of its constituents.
Abstract: Techniques and calculations are presented that give explicit expressions for the over-all performance of a luminescent solar concentrator (LSC) in terms of the intrinsic spectral response and quantum efficiency of its constituents. We examine the single dye (or inorganic ion) LSC with emphasis on the planar geometry. Preliminary data on the degradation of candidate LSC dyes under severe weathering conditions are also given. Armed with our experimental results and analysis of solar absorption, self-absorption, and solar cell efficiency, we present a new genre of solar concentrator with a theory of operation for the device.

402 citations


Journal ArticleDOI
TL;DR: The photovoltaic properties of Schottky barier solar cells, made by dispersing particles of the x form of mental-free phthalocyanine in a binder polymer and sandwiching between NESA (SnO2/Sb) and aluminum electrodes, have been studied as discussed by the authors.
Abstract: The photovoltaic properties of Schottky barier solar cells, made by dispersing particles of the x form of mental‐free phthalocyanine in a binder polymer and sandwiching between NESA (SnO2/Sb) and aluminum electrodes, have been studied. A power conversion efficiency of over 6% for transmitted light at low power densities (0.06 W/m2) has been obtained for monochromatic irradiation at 670 nm. At peak solar power density (1400 W/m2) the extrapolated power conversion efficiency (η) for transmitted 670 nm irradiation decreases to 0.01%. The decrease in η with intensity was attributed to a space charge limitation due to nonlinear resistance. The devices exhibit Voc’s as high as 1.1 V, but are still limited by a field dependent quantum efficiency. Analysis of the action spectra of these devices revealed the formation of a thin photoactive depletion region (∼400 A) at the semiconductor/metal interface. These devices are capable of capturing 30% of the solar spectrum within the photoactive region. The effect of pig...

166 citations


Journal ArticleDOI
TL;DR: In this article, high conductive and transparent thin films of SnO 2 : F and In 2 O 3 : Sn have been prepared using the simple pyrolitic (spray) method.

164 citations


Journal ArticleDOI
TL;DR: In this paper, the authors reported that the active area efficiency of a 3.1-cm2 silicon solar cell was close to the best silicon cell yet produced with 17.6% active-area efficiency (AM1, 28°C).
Abstract: Major new results are reported for silicon MIS solar cells. Open‐circuit voltages up to 655 mV (AM0, 25 °C) have been obtained for 0.1‐Ω cm silicon wafers, substantially higher than previously reported for any other silicon solar cell. On an active‐area basis, the efficiency of these high‐output‐voltage cells is close to the best silicon cell yet produced with 17.6% active‐area efficiency (AM1, 28 °C) for a 3‐cm2 cell.

141 citations


Journal ArticleDOI
TL;DR: In this article, the three-zone salt gradient solar pond is analyzed as a steady-state flat-plate solar energy collector, and the resulting efficiency equation is of the Hottel-Whillier-Bliss type commonly used for flatplate collectors.

139 citations


Journal ArticleDOI
TL;DR: In this article, a parabolic-cylindrical solar collector with a circular receiver tube, with a suitable selective coating, is enclosed by a concentric glass envelope and situated along the focal line of a parabolized trough reflector, where the heat transfer processes which occur in the annular space between the receiver tube and the glass envelope are important in determining the overall heat loss from the tube.
Abstract: An effective device for the collection of solar energy which has received widespread attention is the so called parabolic-cylindrical solar collector. In this design a circular receiver tube, with a suitable selective coating, is enclosed by a concentric glass envelope and situated along the focal line of a parabolic trough reflector. The heat transfer processes which occur in the annular space between the receiver tube and the glass envelope are important in determining the overall heat loss from the receiver tube. In typical high temperature receiver tube designs the rate of energy loss by combined thermal conduction and natural convection is of the same order of magnitude as that due to thermal radiation, and can amount to approximately 6 percent of the total rate at which energy is absorbed by the solar collector. The elimination of conduction and natural convection losses can significantly improve the performance of a large collector field. Several techniques useful for the reduction of energy loss by thermal conduction and natural convection are considered. The receiver configuration chosen for study is typical of those used in the Solar Total Energy System at Sandia Laboratories. The receiver tube has a ''black chrome'' selective coating and is 2.54 more » cm in outside diameter. The inside diameter of the glass envelope is approximately 4.4 cm. Typical operating temperatures of the receiver tube and glass envelope are approximately 300/sup 0/C and 100/sup 0/C, respectively. « less

137 citations


Journal ArticleDOI
TL;DR: In this article, a general design method is presented for closed loop energy systems consisting of solar collectors, sensible energy storage and a closed-loop flow circuit in which thermal energy is supplied (through heat exchange) to a load above a specified minimum temperature.

133 citations


Journal ArticleDOI
TL;DR: In this paper, the correlation between diffuse and total horizontal radiation is reviewed and examined for data on the monthly average daily horizontal radiation collected at several Canadian stations, and a regional correlation is developed based on Toronto-Montreal and Goose Bay data, which is valid for a large region.

132 citations


Journal ArticleDOI
R.M. Swanson1
01 Mar 1979
TL;DR: In this paper, a solar-electric system using concentrated mirrors focusing on a thermophotovoltaic (TPV) converter is proposed and discussed, where the concentrated sunlight heats a refractory radiator.
Abstract: A solar-electric system is proposed and discussed. This system uses concentrated mirrors focusing on a thermophotovoltaic (TPV) converter. Within the TPV converter the concentrated sunlight heats a refractory radiator. A silicon photovoltaic cell faces the radiator, receives incandescent radiation from it, and converts this radiation into electricity.

Journal ArticleDOI
TL;DR: In this article, the fabrication and properties of indium tin oxide/p-Si single-crystal solar cells are described and the effect of temperature on device performance and spectral response are compared with the theory.
Abstract: We have reported on the theory of semiconductor‐insulator‐semiconductor (SIS) solar cells in a previous publication. In this paper, the fabrication and properties of indium tin oxide/p‐Si single‐crystal solar cells will be described. The ITO is deposited by the ion‐beam sputtering method. Best photovoltaic devices are obtained when the composition of indium tin oxide (ITO) is 91 mole% and 9 mole% SnO2. The device properties as a function of the ITO composition will be described. The thickness and the composition of the oxide‐silicon interface is critical for device performance. The existence of a thin interfacial layer is demonstrated by Auger spectroscopy. The effect of temperature on device performance and the spectral response are compared with the theory. The SIS model accurately matches the major trends observed in experimental nITO/p‐Si solar cells.

ReportDOI
01 Sep 1979
TL;DR: In this article, a macroscopic approach that yields all the parameters needed for the optical design of line focus parabolic troughs in closed analytical form, requiring only minimal computation is described.
Abstract: This paper describes a macroscopic approach that yields all the parameters needed for the optical design of line focus parabolic troughs in closed analytical form, requiring only minimal computation.

01 Jan 1979
TL;DR: In this article, the thermal and electric performance of an air and a liquid type combined photovoltaic/thermal solar collector was evaluated, yielding close correlation with theoretical results.
Abstract: The thermal and electric performance of an air and a liquid type combined photovoltaic/thermal solar collector has been evaluated, yielding close correlation with theoretical results. Maximum thermal efficiencies of 42.5% and 40% for the liquid and air collectors without electric power production decreased to 40.4% and 32.9% when electrical power was produced. Maximum electrical efficiencies of 6.8% were measured.


Journal ArticleDOI
TL;DR: In this paper, the authors used reactive sputter etching to texture the surface of Si wafers in the form of pillars whose diameters and spacing were small compared with the useful solar wavelengths and whose heights were comparable with or larger than these wavelengths.
Abstract: We have used reactive sputter etching to texture the surface of Si wafers. The texturing was in the form of pillars whose diameters and spacing were small compared with the useful solar wavelengths and whose heights were comparable with or larger than these wavelengths. The normal and hemispherical reflectances of textured wafers were measured. The solar absorptance was found to be 0.99 for wavelengths below 1.0 μm. Because of the sharp drop in absorptance for photon energies less than the energy gap, the overall solar absorptance was about 0.85. The calculated thermal emittance was about 0.25 and was primarily due to multiphoton absorption processes normally observed in thick Si crystals. Much smaller values of thermal emittance would be obtained from thin textured films.

Journal ArticleDOI
TL;DR: In this paper, the efficiency of a typical basin type solar desalination plant is 30% or lower and the major design factors affecting energy utilization are basin temperature, condensing surface temperature and ambient air temperature.

BookDOI
A. Luque, G. Sala, W. Palz, G. Santos, P. Helm 
01 Jan 1979
TL;DR: In this article, separate abstracts were prepared for 121 of the 129 papers presented and eight papers were previously included in the data base, and introductory speeches were also presented. (WHK)
Abstract: Separate abstracts were prepared for 121 of the 129 papers presented. Eight papers were previously included in the data base. Introductory speeches are also presented. (WHK)

Patent
Gerald G. Murphy1
23 Aug 1979
TL;DR: In this article, a solar energy collection and distribution system is described, where the solar energy collecting elements, arrays or sections are disposed over or floated on a body of water while having associated control, distribution and auxilliary means largely disposed or contained on a land mass adjacent or nearby the body.
Abstract: The present invention relates to solar energy collection and distribution systems and more particularly to such systems wherein the solar energy collecting elements, arrays or sections are disposed over or floated on a body of water while having associated control, distribution and auxilliary means largely disposed or contained on a land mass adjacent or nearby the body of water. The collecting elements or sections may also be supported on frames, structures or platforms slightly above the surface of the body of water to clear wave or tidal action and the like. The invention also relates to associated means and apparatus for energy collection, conversion, conservation and distribution with which to economically and efficiently implement the purposes of the invention and extend its utility over a broad area.

Patent
29 Nov 1979
TL;DR: In this article, an apparatus for collecting solar energy with means of producing electricity by concentrating solar energy on sets of photovoltaic cells to be either positioned at high altitudes and which may be fitted to balloons or to structures floating on water.
Abstract: Disclosed is apparatus for collecting solar energy with means of producing electricity by concentrating solar energy on sets of photovoltaic cells to be either positioned at high altitudes and which may be fitted to balloons or to structures floating on water.

Patent
22 Nov 1979

Patent
26 Sep 1979
TL;DR: In this paper, a combined solar-wind energy conversion system was proposed, in which the combined effects of solar and wind energy are utilized in raising water from a lower to an upper water storage tank to increase its potential energy for generation of electricity.
Abstract: A combined solar-wind energy conversion system in which the combined effects of solar and wind energy are utilized in raising water from a lower to an upper water storage tank to increase its potential energy for generation of electricity. Incoming solar energy heats water to form steam which is temporarily stored. The stored steam is vented to one of first and second steam storage tanks from which it is coupled to first and second water pumping tanks. When the water enters one of the water pumping tanks, it forces the water temporarily stored therein to flow upwards the first steam storage tank. As soon as the water pumping tank is emptied, the steam condenses forming a partial vacuum in the tank. The vacuum causes water to be drawn from the lower water storage tank into the corresponding water pumping tank and the process repeated. The second water pumping tank is filled while the first water storage tank is emptied. Water flowing from the first water storage tank turns an electrical generator. Wind energy is also used to raise water from the second water storage tank to the first water storage tank to increase the available energy. When excess electrical energy is available, it is used to electrolyze water into hydrogen and oxygen which are stored for later burning during periods when insufficient wind and solar energy are available.

ReportDOI
TL;DR: In this article, the benefits of thermal stratification in sensible heat storage were investigated for several residential solar applications, and the results showed that significant improvements in system performance may be realized if stratification can be maintained in the storage tank.
Abstract: The benefits of thermal stratification in sensible heat storage were investigated for several residential solar applications. The operation of space heating, air conditioning and water heating systems with water storage was simulated on a computer. The performance of comparable systems with mixed and stratified storage was determined in terms of the fraction of the total load supplied by solar energy. The effects of design parameters such as collector efficiency, storage volume, tank geometry, etc., on the relative advantage of stratified over well-mixed storage were assessed. The results show that significant improvements in system performance (5 to 15%) may be realized if stratification can be maintained in the storage tank. The magnitude of the improvement is greatest and the sensitivity to design variables is smallest in the service hot water application. The results also show that the set of design parameters which describes the optimum system is likely to be substantially different for a system employing stratified storage than for a mixed storage system. In both the water heating and space heating applications collector flowrates lower than currently suggested for mixed storage systems were found to yield optimum performance for a system with stratified storage.

Journal ArticleDOI
TL;DR: In this paper, the authors developed a probe for measuring hemispheric solar flux and employed it to measure the solar reflectance of a wide variety of building materials and used the measured reflectivity values to demonstrate the change in structure heat gain/loss that can realistically be achieved by altering roof reflectivity.

Patent
19 Nov 1979
TL;DR: In this paper, the authors present a dynamic system for the utilization of solar energy which is most of the time in the ideal position in relation to the sun, consisting of at least one unit consisting of a solar collector and a stand carrying said collector.
Abstract: A dynamic system for the utilization of solar energy which is most of the time in the ideal position in relation to the sun. Said device comprises at least one unit consisting of a solar collector and a stand carrying said collector, means for rotating the solar collector around its horizontal axis and means for rotating the solar collector and/or the stand around the vertical axis; means for simultaneous or independent actuation of the rotation means, means for the tracking control of said actuation means; and means for the transfer of the energy obtained.

Journal ArticleDOI
22 Jun 1979-Science
TL;DR: Variations of the solar radius between 1850 and 1937 are limited to about 0.25 arc second; modeling of the sun indicates that the solar constant did not vary by more than 0.3 percent during that time.
Abstract: Climatically significant variation of the solar constant (the energy output of the sun) implies measurable change in the solar radius. The available data limit variations of the solar radius between 1850 and 1937 to about 0.25 arc second; modeling of the sun indicates that the solar constant did not vary by more than 0.3 percent during that time.

Journal ArticleDOI
TL;DR: In this article, the authors developed a simple analysis of the Coddington equations, the major aberration which describes the optical off-axis image behavior of a focusing collector system.

Book
01 Dec 1979

Patent
21 Mar 1979
TL;DR: In this article, a solar panel module is provided, wherein a plurality of solar panel units are electrically interconnected and supported within a low cost frame assembly, which may conveniently be formed from wood products.
Abstract: A solar panel module is provided, wherein a plurality of solar panel units are electrically interconnected and supported within a low cost frame assembly, which may conveniently be formed from wood products. Each solar panel unit is provided with extending conductors for electrical connections with adjacent solar panels. Each solar panel unit is formed in a back-wall configuration where solar radiation is incident on a transparent vitreous substrate. The panel surface opposite the substrate is sealed, preferably with a bituminous material, to minimize permeation of the solar panel by environmental elements. The sealing material cooperates with the frame to provide an insulated exposed surface. In one embodiment, the completed module is formed to external dimensions generally standard in the building industry for easy installation.

Patent
16 May 1979
TL;DR: In this paper, flat plate reflectors are pivoted to move with the position of the sun and concentrate additional energy on a solar energy collector panel for tracking the sun over its seasonal variations by means of simple mechanisms pivoting the reflector plates.
Abstract: Simple flat plate reflectors, preferably compound of a panel with a reflector surface layer laminated thereto, are pivoted to move with the position of the sun and concentrate additional energy on a solar energy collector panel. The array can take a tented or triangular end view shape for closing to protect reflective surfaces from hail or sandstorm, etc. Also the surfaces are provided with a periodically operable surface cleaner to assure long term efficiency even when remotely positioned as on roof top. Low cost present day computers are programmed to track the sun over its seasonal variations by means of simple mechanisms pivoting the reflector plates. The system is self-energizing by means of batteries charged by solar panels accompanying the system. Solar energy is storable in a self-contained water tank for use at night, etc. and efficient energy conversion is attained by means of a stainless steel pipe length extending into the stored water and thermally coupled outside the tank to a solar heated higher than 100° C. silicon oil circulated through the solar collector. Thus, vaporization is avoided and an effective low-cost simplified thermal energy conversion is effected.