Showing papers on "Solar energy published in 1981"

Exploring the Consumer Decision Process in the Adoption of Solar Energy Systems

Abstract: This study examines residential solar energy systems within an adoption and diffusion of innovations framework. The findings indicate considerable differences between adopters and nonadopters on many measures. Multivariate nominal scale analysis is used to develop classification models based on both attribute perceptions of solar energy systems and demographic characteristics.

Conversion of Sunlight into Electrical Power and Photoassisted Electrolysis of Water in Photoelectrochemical Cells

Abstract: The development of photoelectrochemical solar cells based on semiconductor liquid junctions is discussed. Over the past 6 years, the efficiency of solar energy conversion has increased from < 1% to 12%, and the operational life of these cells has increased from hours to months. Understanding the chemistry of surfaces and grain boundaries has made it possible to manipulate the position of the surface and grain boundary states and thus reduce losses due to electron-hole recombination. Cells exhibiting approx. 12% efficiency of conversion are: (1) chemisorbed Ru/sup 3 +/ ions on n-GaAs photoanodes; (2) diffused Ru/sup 3 +/ and Pb/sup 2 +/ into grain boundaries of polycrystalline n-GaAs films on graphite; (3) p-InP/VCl/sub 3/-VCl/sub 2/-HCl/C cell; and (4) p-InP(Ru)/HCl-KCl/Pt cell. Photoassisted electrolysis of water for conversion of solar energy to hydrogen using the last mentioned photoelectrochemical cell represents the most efficient system for solar energy conversion. 61 references are cited. (BLM)tic stainless steel is required to prevent stress corrosion cracking byd stuffs contamination in the USSR takes place in the framework of variations observed in separate countries of northern hemisphere.

Radiative heating and cooling with spectrally selective surfaces.

Abstract: Matter continuously exchanges energy with its surroundings. This exchange can be dominated by radiation, conduction, or convection. In this brief review we discuss how proper design of radiative surface properties can be used for heating and cooling purposes. The desired properties can be understood once it is realized that solar and terrestrial radiation take place in different wavelength ranges and that only part of the solar spectrum is useful for vision and for photosynthesis in plants. These facts allow the possibility of tailoring the spectral absorptance, emittance, reflectance, and transmittance of a surface to meet different demands in different wavelength intervals, i.e., to take advantage of spectral selectivity. One example is the selective surface for efficient photothermal conversion of solar energy, which has high absorptance over the solar spectrum but low emittance for the longer wavelengths relevant to thermal reradiation. Below we discuss the pertinent spectral radiative properties of our ambience. These data are then used as background to the subsequent sections treating four examples of spectrally selective surfaces. The first example is the previously mentioned selective surface for converting solar radiation to useful heat. The second example considers surfaces capable of reaching low temperatures by benefiting from the spectral emittance of the clear night sky. The third example concerns two related types of transparent heat mirror. The fourth example, finally, treats radiative cooling of green leaves; this part is included since it gives a nice example of how nature solves a difficult problem in an elegant and efficient way. This example hence provides an interesting background to the other cruder types of artificial selective surfaces. Throughout our discussion we treat the ideal spectral properties, give an illustrative experimental example of how well this goal can be realized, and—where this is possible—show a corresponding theoretical curve indicating to what extent the measured results can be theoretically understood.

Solar energy handbook

Abstract: Solar energy handbook , Solar energy handbook , کتابخانه دیجیتالی دانشگاه علوم پزشکی و خدمات درمانی شهید بهشتی

Solar selective surfaces

Abstract: The preparation, properties, and the role of transparent conducting coatings as solar spectrally selective surfaces are discussed. The application of spectrally selective surfaces to photothermal conversion is covered, and the use of transparent conductors in photovoltaic conversion is explored. Measurement techniques used for determining absorptance, emittance, and reflectance are described. The black solar selective surfaces are covered. Much of the presentation is given in a comparative format. 384 references. (LEW)

Plasma Si nitride—A promising dielectric to achieve high-quality silicon MIS/IL solar cells

Abstract: Substantial advantages of plasma Si nitride, for the first time applied to silicon MIS inversion layer (MIS/IL) solar cells, are demonstrated: The highest positive interface charge densities ever used for this type of solar cell (up to 72×1012 cm−2), absolute stability of the charges up to the nitride despoition temperature (220 and 300 °C, respectively), excellent passivation of the entire cell, and good AR coating properties High uv sensitive MIS/IL solar cells were fabricated with these layers on p–Si (100) AM1 efficiencies of 15% (active area) at 25 °C were obtained

Analytical Predictions of Liquid and Air Photovoltaic/Thermal, Flat-Plate Collector Performance

Abstract: Two separate one-dimensional analyses have been developed for the prediction of the thermal and electrical performance of both liquid and air flat-plate photovoltaic/thermal (PV/T) collectors. The analyses account for the temperature difference between the primary insolation absorber (the photovoltaic cells) and the secondary absorber (a thermal absorber flat plate). The results of the analyses are compared with test measurements, and therefrom, design recommendations are made to maximize the total energy extracted from the collectors.

Optimization of Flow Passage Geometry for Air-Heating, Plate-Type Solar Collectors

Abstract: The effect of the choice of shape and dimensions of the air flow passages in plate-type, air-heating solar collectors is assessed. Particular examination is made of their effect on the overall heat transfer coefficient between the air stream and the plate, which has an important effect on collector efficiency. It is emphasized in this study that in comparing various designs of flow passage, they should be compared for the same pressure drop suffered by the air in passing through the collector, and for the same mass flow rate m per unit of collector area. 11 refs.

NREL Solar Radiation Research Laboratory (SRRL): Baseline Measurement System (BMS); Golden, Colorado (Data)

Abstract: The SRRL was established at the Solar Energy Research Institute (now NREL) in 1981 to provide continuous measurements of the solar resources, outdoor calibrations of pyranometers and pyrheliometers, and to characterize commercially available instrumentation. The SRRL is an outdoor laboratory located on South Table Mountain, a mesa providing excellent solar access throughout the year, overlooking Denver. Beginning with the basic measurements of global horizontal irradiance, direct normal irradiance and diffuse horizontal irradiance at 5-minute intervals, the SRRL Baseline Measurement System now produces more than 130 data elements at 1-min intervals that are available from the Measurement & Instrumentation Data Center Web site. Data sources include global horizontal, direct normal, diffuse horizontal (from shadowband and tracking disk), global on tilted surfaces, reflected solar irradiance, ultraviolet, infrared (upwelling and downwelling), photometric and spectral radiometers, sky imagery, and surface meteorological conditions (temperature, relative humidity, barometric pressure, precipitation, snow cover, wind speed and direction at multiple levels). Data quality control and assessment include daily instrument maintenance (M-F) with automated data quality control based on real-time examinations of redundant instrumentation and internal consistency checks using NREL's SERI-QC methodology. Operators are notified of equipment problems by automatic e-mail messages generated by the data acquisition and processing more » system. Radiometers are recalibrated at least annually with reference instruments traceable to the World Radiometric Reference (WRR). « less

Sun rhythm form

Abstract: While solar technology for individual buildings has become an accepted part of architectural design, Knowles takes the next innovative step. In this book, he proposes solar access in urban environments with a novel design method called the "solar envelope."

Zinc phosphide‐zinc oxide heterojunction solar cells

Abstract: The photovoltaic properties of p‐Zn3P2/n‐ZnO heterojunction solar cells prepared by sputter deposition of ZnO on Zn3P2 substrates are reported. An active‐area power conversion efficiency of ∼2% has been obtained. The experimental results are discussed on the basis of an interface recombination model. The interface plays a significant role in determining the performance of the device.

Modular solar greenhouse with elevated overhead heat storage material and movable insulation barriers and method and system for solar heating of attached living space using thermostat-controlled air circulation for harvesting heat

Abstract: A modular solar greenhouse incorporates rigid curving frames overhead with screw and nut tracks for ease of assembly and east side and west side end modules and advantageously employs a thermally broken glazing system; that is, the exterior and interior portions of the aluminum frame extrusions are bonded together by strong plastic material and then the metal bridge is removed for thermally isolating the interior frame portion from the exterior portion. At least one overhead heat storage unit is carried by the rigid frames, with insulated roofing being located above and also being supported by the frames, so that low-angle solar radiation in the wintertime can travel directly into the upper region of the greenhouse below the roof for directly impinging upon and supplying heat energy to the thermal storage units. Movable, reflective insulation barriers or curtains are extendible for enclosing the solar greenhouse for retaining warmth resulting from stored solar heat energy in the overhead storage units during winter nights.

Effects of dust on the performance of thermal and photovoltaic flat plate collectors in Saudi Arabia: preliminary results

Abstract: The effect of dust accumulation on the surfaces of flat plate thermal and photovoltaic collectors has been studied and preliminary results are presented. One photovoltaic and two thermal panels were tested and the degradation in performance due to surface dust was determined. 10 refs.

Solar tracking apparatus utilizing photovoltaic flat panels and method

Abstract: A technique for converting solar energy directly to electrical energy is disclosed herein and utilizes a plurality of photovoltaic-like flat panels having solar collecting front sides. These panels are supported for simultaneous rotation about a given axis, preferably a horizontal or south sloping axis, while their solar collecting front sides face the same direction. At the same time, these front sides are maintained in end-to-end relationship with one another within a common plane, preferably one which is at all times parallel with the axis of rotation. In actual operation, the photovoltaic-like panels are simultaneously rotated about their given axis in tracking relationship with the sun, preferably so as to maintain the solar collecting front sides of the panels at a fixed acute angle with respect to the sun's rays. Moreover,the panels are preferably supported adjacent to one another in a way which minimizes the distance between endmost panels.

Glass heat pipe evacuated tube solar collector

Abstract: A glass heat pipe is adapted for use as a solar energy absorber in an evacuated tube solar collector and for transferring the absorbed solar energy to a working fluid medium or heat sink for storage or practical use. A capillary wick is formed of granular glass particles fused together by heat on the inside surface of the heat pipe with a water glass binder solution to enhance capillary drive distribution of the thermal transfer fluid in the heat pipe throughout the entire inside surface of the evaporator portion of the heat pipe. Selective coatings are used on the heat pipe surface to maximize solar absorption and minimize energy radiation, and the glass wick can alternatively be fabricated with granular particles of black glass or obsidian.

Solar cell arrangement

Abstract: A solar cell arrangement with an associated optical collecting lens system The lens system focuses a light impingement area onto the solar cell to intensify incident radiation The collecting lens system includes an optically active layer provided between the light impingement area and the solar cells The optically active layer images and disperses the incident light in a manner adapted to the surface and light absorption characteristics of the solar cells

Tracking arrangement for a solar energy collecting system

Abstract: A solar energy collecting system of the tracking type is disclosed herein and includes at least one but preferably a plurality of solar panels mounted for movement along respective predetermined tracking paths such that each maintains a predetermined orientation with respect to the sun as the latter moves across the sky. The disclosed system also includes a single, common device which serves both as a direct insolation monitor for detecting the presence or absence of direct sunlight and as a means of detecting the position of the sun if direct sunlight is found to be present. Each panel includes a second device mounted for movement therewith for sensing the position of the panel at any given time and, at the same time, for detecting whether or not the panel is at the desired orientation with the sun. These latter devices cooperate with the first-mentioned common device for maintaining their associated solar panels in precise, controlled orientation with the sun so long as direct sunlight is present. The overall system also includes a remote arrangement for controlling the various solar panels in other prioritized ways utilizing "touch tone" signals, that is, dual tone multi-frequency (DTMF) signals.

Solar energy concentrator system

Abstract: A solar energy concentrator system having a plurality of concentrator arrays with each of the arrays being made up of a plurality of adjacent longitudinally extending concentrator modules. Each of the concentrator modules has a semi-cylindrically-shaped housing and a semi-cylindrically-shaped cover in order to form an overall cylindrically-shaped structure which provides protection from adverse environmental conditions and withstands high wind loads. Situated within the cover and connected to the housing is a parabolically-shaped concentrator. The concentrator is made up of a plurality of parallelogram-shaped reflector panels mounted adjacent one another on a bias. This arrangement permits the ends of the panels to overlap adjacent modules so as to provide a substantially continuous reflector surface. The reflector surface redirects solar energy onto a plurality of solar cells located within the cover and as a result of the physical makeup of the concentrator components substantially eliminates the problem of cell shadowing.

Passive solar design handbook

Abstract: The Passive Solar Design Handbook, Volume Three updates Volume Two by presenting extensive new data on the optimum mix of conservation and solar direct gain, sunspaces, thermal storage walls, and solar radiation. The direct gain, thermal storage wall, and solar radiation data are greatly expanded relative to the Volume 2 coverage. The needed flexibility to analyze a variety of system designs is accommodated by the large number of reference designs to be encompassed - 94 in contrast to 6 in Volume two - and the large amount of sensitivity data for direct gain and sunspace systems - approximately 1100 separate curves.

Thermal analysis of three zone solar pond

Abstract: This paper presents a periodic analysis of a three zone solar pond as a solar energy collector and long term storage system. We explicitly take into account the convective heat and mass flux through the pond surface and evaluate the temperature and heat fluxes at various levels in the pond during its year round operation by solving the time dependent Fourier heat conduction equation with internal heat generation resulting from the absorption of solar radiation in the pond water. Eventually, an expression, for the transient rate at which heat can be retrieved from the solar pond to keep the temperature of the zone of heat extraction as constant, is derived. Heat retrieval efficiencies of 40.0 per cent, 32.1 per cent, 28.3 per cent and 25.5 per cent are predicted at collection temperatures of 40, 60, 80 and 100°C, respectively. the retrieved heat flux exhibits a phase difference of about 30 to 45 days with the incident solar flux; the load levelling in the retrieved heat flux improves as the thickness of the non-convective zone increases. the efficiency of the solar pond system for conversion of solar energy into mechanical work is also studied. This efficiency is found to increase with collection temperature and it tends to level around 5 per cent at collection temperatures about 90°C.

Solar energy conversion by chloroplast photoelectrochemical cells

Abstract: Solar energy can be captured by photochemical or photoelectric processes in which a gradient of chemical potential can be generated using photochemical redox reactions. Photosynthesis is the most efficient system for quantum conversion and storage of solar energy1. Various biomimetic systems have been constructed as models for the conversion of light to electrical energy2–11. These biological photoelectrochemical cells have utilized macrocrystalline chlorophyll a (Chl a)2, chlorophyll liquid crystals deposited on the electrodes3–5 or incorporated into filters6, bilayer lipid membranes7, chloroplast membranes8, chloroplasts9 and bacterial reaction centres10,11. The power conversion efficiencies are mostly very low (≈0.002%). We describe here a chloroplast photoelectrochemical cell which generates large photovoltage and photocurrent, and has a power conversion efficiency close to 1%.

High efficiency solar cell structure

Abstract: The invention relates to a new-type of solar cell structure, and to a method of manufacturing same. The solar cell is designated as an MINP cell (Metal-Insulator-NP junction solar cell). Essentially, the MINP solar cell is an extremely shallow N-P junction cell with a MIS (Metal-Insulator-Semiconductor) type contact made to the top of the cell. Although combining features of the two technologies, no more processing steps are required than for a conventional P-N junction cell. The advantage of the MINP structure is its substantially improved efficiency.