Showing papers on "Photovoltaic system published in 1985"

Active solar collectors and their applications

Abstract: 1: Survey of Solar Equipment and Applications 2: Solar Geometry 3: Insolation Data and Models 4: Collector Efficiency and Collector Testing 5: Fundamentals of Optics for Solar Collectors 6: Optics of Nontracking Collectors 7: Tracking Concentrator Types 8: Optical Analysis and Optimization of Parabolic Reflectors 9: Heat Transfer in Solar Collectors 10: Heat Transfer Factors 11: System Models 12: Applications 13: Practical Considerations 14: Economic Analysis 15: System Optimization Appendix A. Nomenclature Appendix B. Units Appendix C. Properties of Materials Appendix D. Meteorological Data Appendix E. Circumsolar Data Index

Method of and system for controlling a photovoltaic power system

Abstract: In a method of and a system for controlling a photovoltaic power system including a solar battery and a power converter receiving the output of the solar battery, the voltage of the solar battery is kept at a voltage reference which is determined in accordance with the operating condition of the system thereby to maximize the power of the solar battery. Operating mode is switched between a first mode in which the voltage reference is periodically decreased and a second mode in which the voltage reference is periodically increased. The switching between the first and the second mode is effected in accordance with the direction of change of the power and the voltage of the solar battery. Where there is a reactance between the solar battery and the point at which the voltage or the current is detected, or a time lag element in a voltage detector or a current detector, an arrangement may be provided to compensate detection error due to the reactance or the time lag element.

DC-AC converting arrangement for photovoltaic system

Abstract: An improved DC-AC converting arrangement for a photovoltaic system, which makes it possible to supply power at high efficiency by providing a driving control system arranged to stop operation of a DC-AC converter when a load power of the DC-AC converter falls below a predetermined reference value, and to restart the operation of the DC-AC converter when the load power exceeds the predetermined reference value.

The Effect of Photovoltaic Power Generation on Utility Operation

Abstract: This paper presents an evaluation of the effect on utility operation of photovoltaic (PV) generation that is interconnected to an electric utility grid. Various PV concentrations and performance characteristics are examined and the effect on utility generation control performance is evaluated.

Interface control for storage battery based alternate energy systems

Abstract: An alternate energy interface control for implementation with utility derived power sources and alternate power sources such as are provided by solar panels, windmills, and the like employed with systems utilizing storage batteries. The system monitors the current level of photovoltaic solar panels within intervals during such panels are connected with the battery storage source and further monitors the voltage levels developed by such panels during normal open circuit conditions thereof. A logic control is provided which monitors alternate source currents and voltage as well as storage battery voltage levels to prioritize the use of available alternate energy sources. Battery charging during periods of alternate power source availability is with a pulsed technique to enhance battery lifespans.

Hybrid solar energy generating system

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.

Solar thermophotovoltaics: An assessment

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.

Solar energy systems design

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.

Methods for Measuring Solar Cell Efficiency Independent of Reference Cell or Light Source

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.

Solar energy power generation system

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

Solar powered automobile cooling system

Abstract: An automobile cooling system where electrical energy derived from solar cells are used to drive the pump and fan of a vehicle mounted evaporative cooling system. Automatic control of the system is provided by a thermostatic switch located within the vehicle.

Current and lattice matched tandem solar cell

Abstract: A multijunction (cascade) tandem photovoltaic solar cell device is fabricated of a Ga x In 1-x P (0.505≦X≦0.515) top cell semiconductor lattice matched to a GaAs bottom cell semiconductor at a low-resistance heterojunction, preferably a p+/n+ heterojunction between the cells. The top and bottom cells are both lattice matched and current matched for high efficiency solar radiation conversion to electrical energy.

Solar array regulator

Abstract: Apparatus for regulating the voltage output of a solar cell array by selectively actuating individual cells that have been constructed to include a light control valve capable of being rendered opaque or transparent under electrical control By automatically controlling selected cells in the array in this manner, the output characteristics of the array can be regulated to compensate for variations caused by temperature or other changes

Solar Water Pumping

Abstract: Foreword Acknowledgements List of Figures List of Tables 1. Is Solar Pumping for You? 1.1 Purpose of this Handbook 1.2 Energy for Water Pumping 1.3 The Solar Resource 1.4 Typical Water Pumping Applications 1.5 Overview of Solar Pump Viability 2. The Technology 2.1 Photovoltaic Pumping Systems 2.2 Photovoltaic Arrays 2.3 The Motor and Pump Subsystem 2.4 Storage and Distribution 2.5 A Typical Day's Operation 3. Site Evaluation 3.1 Assessing Water Requirements 3.2 Solar Energy Availability 3.3 System Sizing 3.4 Specifying Performance 4. Economic Assessment 4.1 Methodologies for Economic Evaluation 4.2 Procedure for a Cost Appraisal of Water Pumping 4.3 Guidance on Costs and Economic Viability 5. Procurement, Installation and Monitoring 5.1 Procurement 5.2 Installation and Operation 5.3 Monitoring and Evaluation Appendix 1. Solar Radiation Data Appendix 2. Present Worth Factors Appendix 3. Equations used for system sizing Appendix 4. Examples Appendix 5. Blank Format Sheets Appendix 6. Example Tender Documents Appendix 7. Glossary and List of Symbols Used

Integrated PV-thermal panel and process for production

Abstract: This invention relates to producing electricity and heat by means of a hybrid solar panel. Some of the energy (about 10%) is taken off electrically at the top. The rest goes through as infrared heat to an exchange fluid below. The invention includes a means of producing photovoltaic (not just photoconductive) surfaces continuously on copper sheet substrates, without pulling or cutting conventional crystalline boules or ribbons. Significant time, labor, and cost may be saved.

Photovoltaic cell package assembly for mechanically stacked photovoltaic cells

Abstract: A mechanically stacked module package is described. The package permits the effective mechanical stacking of two solar cells in a compact arrangement. The design also permits the easy wiring of the package into a voltage matching configuration for module wiring thus eliminating the problems of current matching the top and bottom cells. The package design can be used with any mechanically stacked cells although the design is most suitable for concentrator solar cell configurations where the removal of heat to avoid degradation and shortening of lifetime is a major concern.

Mobile solar station which can be combined with a wind-energy generator

Abstract: The mobile solar station combined with a wind-energy generator, photovoltaic panels, a water-conveying pump, a drinking-water and service-water treatment installation and a service-water heating system, is a novel variant of the alternative use of energy and opens up novel perspectives for the environmentally friendly, humane use of self-sufficient, decentralised energy supply installations of ultra-small dimensions.

Solar power take off

Abstract: A system for converting DC electrical solar generated energy to AC electrical energy. A DC motor is driven by electricity obtained from DC electrical energy producing solar panels. The DC motor drives an air compressor which in turn provides, via Archimedes' principle, a constant flow of air to a submerged cross-flor turbine. The turbine is rotated by the rising air bubbles through the water. An AC generator is connected to the shaft of the turbine. The output of the AC generator is connected to the shaft of the turbine. The output of the AC generator is then fed to the consumer's or homeowner's electrical supply lines. Special cleaning means removes impurities from the air flowed through the cross-flow turbine.

Thin-Film Multilayer Filter Designs For Hybrid Solar Energy Conversion Systems

Abstract: The efficiency of hybrid photothermal/photovoltaic energy conversion can be increased by separating the solar spectrum into portions matched to the photothermal and photovoltaic processes. Thin-film multilayer filters can implement this concept; five such filters consisting of all-dielectric or metal-dielectric layers have been designed. The transmission profile of each design is calculated by computer, considering dispersion, absorption, and angle of incidence effects. These profiles are compared and evaluated with respect to the desired spectral performance. The most successful candidate design is an optical minus filter consisting of Ti0 2 , Zr0 2 , and Si0 2 . Results show very sharp selection of the targeted photovoltaic spectral region and low ripple in the transmission region outside the bandstop.

Spectral Selectivity Applied To Hybrid Concentration Systems

Abstract: The efficiency of conversion of concentrated solar energy can be improved by separating the solar spectrum into portions matched to specific photoquantum processes and the balance used for photothermal conversion. The basic approaches of spectrally selective beam splitters are presented. A detailed simulation analysis using TRNSYS is developed for a spectrally selective hybrid photovoltaic/photothermal concentrating system. The analysis shows definite benefits to a spectrally selective approach.

Recent Progress of Amorphous Silicon Solar Cell Technology

Abstract: A review is given on recent progress in the amorphous silicon solar cells and their technologies. Firstly, some unique advantages of amorphous silicon as a low cost solar cell material are pointed out, and its significant position in the photovoltaic project are discussed. Secondly, newly developed key technologies for improving the photovoltaic performance are demonstrated from the film quality improvement to new junction structure solar cells with a wide and narrow energy gap amorphous silicon alloys. Then, current state of the art in the cell performance are summarized. In the final part, recent feature of the industrializations in both consumer and power application fields are overviewed.

Analysis Of Spectrally Selective Liquid Absorption Filters For Hybrid Solar Energy Conversion

Abstract: Various techniques have been proposed to convert solar energy to both electric power and heat in hybrid systems. Many of these approaches are designed to utilize spectral selectivity to improve the overall conversion efficiency. Examples include spectrally selective beamsplitters and arrangements of long-wave or short-wave-pass glass filters that divide the spectrum so that photon energies are roughly matched to the energies corresponding to the solar-cell bandgaps or to efficient photothermal convertors. This paper describes the analysis of liquid optical filters that have high transmittance in the visible spectrum and high absorptance in the infrared. These qualities make it possible to capture that portion of the spectrum useful to a quantum convertor, such as a photovoltaic cell, while channeling the "excess heat" of the photons with energies below the bandgap to a thermal convertor, thereby enhancing the overall conversion efficiency of the system. The preliminary studies show that spectral responses of the tested solutions (salts in water) are primarily influenced by the cation component of the salt solution. By changing the solutions and concentrations, a variety of spectrally selective filters can be tailored to match system requirements.