Showing papers on "Solar energy published in 1985"
Proceedings Article•
01 Jan 1985
445 citations
TL;DR: In this paper, direct normal and global spectral solar irradiance data sets are presented for selected terrestrial conditions, along with a brief review of previous data sets, covering the 0.305 μm to 4.045 μm region and were generated with the rigorous BRITE Monte Carlo radiative transfer code.
258 citations
TL;DR: In this article, the energy loss mechanisms of a parabolic dish/cavity receiver configuration are analyzed and power profiles produced in cavities of varying geometry with concentrators of varying rim angle are discussed.
178 citations
TL;DR: In this article, the angular acceptance function of two-dimensional compound parabolic concentrator solar collectors of arbitrary degree of truncation is derived for the optical and thermal losses in real collectors, and the increase in monthly and yearly collectible energy is evaluated.
111 citations
Book•
01 Jan 1985
TL;DR: In this paper, a course in solar engineering in four-year programs is designed to cover the latest advances of the past five years in addition to the basics necessary for student understanding.
Abstract: Designed for a course in solar engineering in four-year programs, this text covers the latest advances of the past five years in addition to the basics necessary for student understanding. It includes discussions of the most promising industrial applications, particularly in the high temperature range and emphasizes complete system design and economic considerations as well as individual component design and specification.
100 citations
TL;DR: A survey of surface coatings for energy efficiency and solar applications can be found in this article, where the authors give a brief overview of recent work on surface coating for solar and passive cooling devices.
Abstract: This paper gives a brief survey over some recent work on surface coatings for energy efficiency and solar applications. Specifically, it covers coatings for - selective absorption of solar energy (for solar collectors), - selective emission of infrared radiation in the 8-13 μm range (for passive cooling devices), - visible transmission combined with near-infrared reflectance (for windows with decreased inlet of solar energy), - solar transmission combined with thermal-infrared reflectance (for windows with decreased outlet of thermal radiation), - variable transmission of solar or visible radiation (for "smart windows" with dynamic control of radiant energy). One general conclusion from the survey is that the research field embodying these types of coatings remains, with a few exceptions, in a state of rapid progress.
99 citations
Patent•
18 Mar 1985TL;DR: In this article, a retractable power supply including a solar cell for converting incident radiation to electrical energy and a base member for storing the solar cell when said cell is not operatively deployed and supporting it when it is in an operative condition.
Abstract: A retractable power supply including a solar cell for converting incident radiation to electrical energy and a base member for (1) storing the solar cell when said cell is not operatively deployed and (2) supporting the solar cell when said cell is in an operative condition. A rechargeable battery pack may be included in the base member for storing electrical energy generated by the solar cell. In one particularly noteworthy embodiment, the solar cell may be employed as a retractable window shade.
91 citations
TL;DR: In this article, the benefits of using phase-change slurries as enhanced heat-transfer/storage working fluids in solar energy and waste heat utilization systems are discussed. But, the authors do not consider the use of phase change material as the dispersed phase.
Abstract: This paper is concerned with the benefits of using phase-change slurries as enhanced heat-transfer/storage working fluids in solar energy and waste heat utilization systems. Literature is cited to show that a slurry containing a phase-change material as the dispersed phase promises to have much higher heat-transfer coefficients than conventional single-phase working fluids. Because of the latent heat, the phasechange slurry also requires lower pumping rates and smaller storage tanks than single-phase fluids for the same energy content. These benefits are documented by comparisons of temperature drops, pumping rates, pumping powers, and the sizes of storage tanks for a generic energy collection system operating with and without a slurry.
TL;DR: In this paper, correlations of the solar radiation for the Athens area are provided, based on hourly measurements over the period 1955-1980, and correlations are of two kinds: the first, which provides the average total radiation incident on a horizontal surface in terms of hour, day, and month of the typical year, is suitable for solar energy collection applications, and the second kind provides the maximum radiation and are suitable for use in the design of airconditioning installations or other applications requiring knowledge of maximum values.
TL;DR: In this article, a back-side pointcontact geometry was used for thin high resistivity concentrator silicon solar cells, which achieved an efficiency of 22 percent for incident solar intensities of 3 to 30 W/cm2(30-300 "suns").
Abstract: Experimental results are presented for thin high resistivity concentrator silicon solar cells which use a back-side point-contact geometry. Cells of 130 and 233 µm thickness were fabricated and characterized. The thin cells were found to have efficiencies greater than 22 percent for incident solar intensities of 3 to 30 W/cm2(30-300 "suns"). Efficiency peaked at 23 percent at 11 W/cm2measured at 22-25°C. Strategies for obtaining higher efficiencies with this solar cell design are discussed.
TL;DR: In this paper, the authors considered a cycle which combines indirect evaporative cooling with a dehumidifier to meet latent loads and a vapour compression refrigeration unit to meet sensible load.
Patent•
19 Aug 1985
TL;DR: In this paper, a hybrid solar energy generating system for effectively utilizing the total solar spectrum gathered by a solar ray concentrator is presented. But the system is not suitable for high-temperature heat generation.
Abstract: A hybrid solar energy generating system for effectively utilizing the total solar spectrum gathered by a solar ray concentrator. The system includes a first solar ray receiver having fluid-cooled photovoltaic solar cells for generating electricity and low-temperature heat. A second solar ray receiver is provided for generating high-temperature heat. A lens focuses the solar rays on the first receiver. A selective transmitting heat-mirror is positioned between the lens and the first solar ray receiver for reflecting selected portions of the solar ray spectrum to the second solar ray receiver and passing essentially the remaining solar ray spectrum to the first solar ray receiver. The heat-mirror reflects all solar rays having wavelengths longer than the long-wave spectral response cut-off of the photovoltaic solar cells and a selected part of the solar rays having wavelengths shorter than the long-wave spectral response cut-off. The heat-mirror spectral profile shape is modified to maximize the conversion of solar energy to high-temperature heat while causing only a minimal decrease in the generation of photovoltaic electricity.
TL;DR: In this article, the results of a more detailed optical and electrical characterization of these devices were described, and it was shown that the high performance of the cells is due to a high optical efficiency and near ideal junction characteristics combined with low parasitic resistance losses.
Abstract: Preliminary results on silicon solar cells of improved performance recently have been described. The present paper describes the results of a more detailed optical and electrical characterization of these devices. The high performance of the cells is shown to be due to a high optical efficiency and near ideal junction characteristics combined with low parasitic resistance losses.
TL;DR: In this paper, double-layer thin films of SiO2 and TiO2, applied using the sol-gel process, were utilized as antireflection coatings on silicon solar cells.
TL;DR: The polysilicon-back solar cells as discussed by the authors showed improvements in red spectral response (RSR) and open-circuit voltage, and a decrease in effective surface recombination velocity S is responsible for this improvement.
Abstract: We report the first use of a (silicon)/(heavily doped polysilicon)/(metal) structure to replace the conventional high-low junction or back-surface-field (BSF) structure, of silicon solar cells. Compared with BSF and back-ohmic-contact (BOC) control slimples, the polysilicon-back solar cells, show improvements in red spectral response (RSR) and open-circuit voltage. Measurement reveals that a decrease in effective surface recombination velocity S is responsible for this improvement. Decreased S results for n-type (Si:As) polysilicon, consistent with past findings for bipolar transistors, and for p-type (Si:B) polysilicon, reported here for the first time. Though the present polysilicon-back solar cells are far from optimal, the results suggest a new class of designs for high efficiency silicon solar cells. Detailed technical reasons are advanced to support this view.
TL;DR: In this article, a general model of a solar thermophotovoltaic device is discussed both for improving the efficiency of one-band-gap photivoltaic cells by matching the photon energy to the band gap and for concentrating diffuse radiation.
Abstract: A general model of a solar thermophotovoltaic device is discussed both for improving the efficiency of one‐band‐gap photovoltaic cells by matching the photon energy to the band gap and for concentrating diffuse radiation. First we assume ideal components to calculate theoretical maximum efficiency. It corresponds to that of a perfect selective absorber in conjunction with a Carnot‐engine ranging from 53% for 1 sun to 85% for the highest possible irradiance of 5×104 suns. The improvement over an ideal one‐gap device is roughly a factor of 2. Consideration of available materials shows that any improvement in efficiency can be expected only for high irradiance of 1000 suns. The sensitive parameter is the selectivity of the absorber‐emitter. Concentration of diffuse solar radiation is not feasible. Perspectives appear not much better than for existing technologies such as photovoltaics or solar tower applications.
TL;DR: In this article, the results of an analytical study using the TRNSYS simulation program in which the thermal performance of domestic hot water systems utilizing alternative control strategies are compared while operating under realistic conditions in several different climates of the United States.
Abstract: Although the performance of solar domestic hot water (SDHW) systems has been well studied, there are several promising control alternatives that have not been thoroughly investigated Reduced constant collector fluid flow rates, variable collector flow rates, and variable volume storage are several alternative strategies This paper presents the results of an analytical study using the TRNSYS simulation program in which the thermal performance of SDHW systems utilizing alternative control strategies are compared while operating under realistic conditions in several different climates of the United States The effects on system performance of time of year, collector area and quality, preheat storage tank volume and energy losses, occurrence of mixing the preheat storage tank, controller temperature deadbands, auxiliary set temperature, total daily usage, and load distribution are investigated
TL;DR: In this article, a reverse osmosis desalination system using positive displacement energy recovery pumps and operating at lower than usual pressures on high rejection membranes can achieve specific energy consumptions below 4 kWh/m3 of product water converted from sea water, less than half the energy requirement without energy recovery.
TL;DR: In this paper, the vertical profile of the upward and downward broadband flux of sunlight at a solar zenith angle of 65.7° was used to evaluate the solar heating rate at cloud levels as a function of altitude, solar longitude, and latitude.
Book•
01 Jun 1985
TL;DR: In this paper, the authors present a review of the first phase of solar involvement of the utility industry with a large amount of data analyzed, including success and failures of different types of experiments.
Abstract: In Volume 6 of the Advances in Solar Energy we have specifically targeted for a review the rich experience of the Power Utilities. Their hands-on experience in a large variety of means to employ solar energy conversion and to evaluate the technical and economical feasibilities is of great importance to their future use. In designing the lay-out for this volume, we wanted to collect all relevant information, including success and failures and wanted to emphasize the lessons learned from each type of experiment. The publication of such a review now has the advantage of a settled experience in the first phase of solar involvement of the utility industry with a large amount of data analyzed. We are confident that this information will be of great value to direct the future development of the solar energy mix within this industry. We have added to this set of reviews three articles which deal with the most promising high-technology part of solar energy conversion using exclusively solid state devices: solar cells. The development over the last two decades from barely 10% to now in excess of 30% conversion efficiency is breathtaking. In addition, the feasibility of economic midrange efficient thin-film technology holds the promise of opening large sc ale markets in the near future. This field will enter head-on competition for large power generation with more conventional technology.
TL;DR: In this article, the degradation of amorphous silicon solar cells is described by a model in which the carrier lifetimes are determined by the dangling bond density, and the degradation will be slower in solar cells operating at lower excess carrier concentrations.
Abstract: The light‐induced performance degradation of amorphous silicon solar cells is described well by a model in which the carrier lifetimes are determined by the dangling bond density. Degradation will be slower in solar cells operating at lower excess carrier concentrations. This is documented with a comparison of degradation data for cells at open circuit versus load, and for single versus cascade cells. At sufficiently long times, the efficiency will decrease at approximately the same rate for all cases, with an offset in time between the individual cases which can be calculated.
Book•
01 Jan 1985TL;DR: In this article, the authors present a broad overview of active and passive solar energy systems, including flat-plate solar collectors and swimming pool and spa-based solar energy system.
Abstract: SOLAR ENERGY: BASIC PRINCIPLES: Basic Physics Review Heat Energy and Heat Transfer Solar Radiation Building Heating Loads PASSIVE SOLAR ENERGY SYSTEMS: Passive Solar Design Concepts Direct-Gain Passive Systems Indirect-Gain and Isolated-Gain Passive Systems Advanced Passive Methods - Selected Applications ACTIVE SOLAR ENERGY SYSTEMS: Introduction to Active Solar Energy Systems Flat-Plate Solar Collectors Performance of Flat-Plate Collectors Solar Heating of Domestic Hot Water Solar Heating of Swimming Pools and Spas Solar Energy System for Space Heating Summer Cooling of Solar Buildings Commercial and Industrial Applications of Solar Energy ELECTRICITY FROM THE SUN: Solar-Energized Electric Power Appendixes Selected References Glossary of Solar Energy Terms.
TL;DR: In this paper, a new type of selenium solar cell with a titanium dioxide (TiO2)/Se heterojunction has been fabricated by low-cost process, achieving an efficiency of 5.01% under AM 1.5 illumination (100 mW/cm2) without antireflection coatings.
Abstract: A new type of selenium solar cell with a titanium dioxide (TiO2)/Se heterojunction has been fabricated by low-cost process. An efficiency of 5.01% under AM 1.5 illumination (100 mW/cm2) has been achieved without antireflection coatings. The corresponding short-circuit current density, open-circuit voltage, and fill factor are 10.8 mA/cm2, 0.884 V, and 0.525, respectively. The efficiency is the highest among Se-based solar cells reported to date. These cells also have extremely high spectral response at short wavelengths, resulting in efficiencies of 11–13% under fluorescent light (500 lux).
01 Jan 1985
TL;DR: In this article, a methodology is presented for calibrating reference cells and calculating spectral mismatch factors, and then using these to obtain the corrected short-circuit current with respect to standard test conditions.
Abstract: The accurate measurement of the photovoltaic conversion efficiency under standard test conditions is essential for meaningful comparisons of the device performance of different types of solar cells. A methodology is presented for calibrating reference cells and calculating spectral mismatch factors, and then using these to obtain the corrected short-circuit current with respect to standard test conditions.
Patent•
23 Jan 1985
TL;DR: An apparatus for producing, in a controlled manner, electrical energy from a solar powered Stirling engine by storing solar energy in a phase change medium and inserting and withdrawing heat exchange means into and out of the medium on demand to supply energy input to the engine.
Abstract: An apparatus for producing, in a controlled manner, electrical energy from a solar powered Stirling engine by storing solar energy in a phase change medium and inserting and withdrawing heat exchange means into and out of the medium on demand to supply energy input to the Stirling engine The Stirling engine drives an electrical generator producing electricity The electricity, in turn, is used for operating a hydrogen generator which produces hydrogen that is stored in a tank for subsequent use as a source of energy
TL;DR: In this paper, the authors examined some of the methods of prediction of global solar radiation and showed that the methods were of reasonable values, provided the parameter K is appropriately adjusted Equation (4) shows, generally, larger values than actual values.
TL;DR: In this article, the effects of inhomogeneous doping and/or composition profiles in the active regions of AlGaAs/GaAs heteroface solar cells have been studied using a realistic computer model.
Abstract: The effects of inhomogeneous doping and/or composition profiles in the active regions of AlGaAs/GaAs heteroface solar cells have been studied using a realistic computer model. It is found that for n‐p devices with moderate surface recombination velocities S, only modest improvements in the cell efficiency are obtained by including linear or exponential profiles. Such gradients become more valuable, however, whenever (1) S increases, (2) the solar illumination is increased through concentration, or (3) a p‐n device is desired.