Showing papers on "Solar power published in 1974"

Feasibility study of a satellite solar power station. Final report

Abstract: A feasibility study of a satellite solar power station (SSPS) was conducted to: (1) explore how an SSPS could be flown and controlled in orbit; (2) determine the techniques needed to avoid radio frequency interference (RFI); and (3) determine the key environmental, technological, and economic issues involved. Structural and dynamic analyses of the SSPS structure were performed, and deflections and internal member loads were determined. Desirable material characteristics were assessed and technology developments identified. Flight control performance of the SSPS baseline design was evaluated and parametric sizing studies were performed. The study of RFI avoidance techniques covered (1) optimization of the microwave transmission system; (2) device design and expected RFI; and (3) SSPS RFI effects. The identification of key issues involved (1) microwave generation, transmissions, and rectification and solar energy conversion; (2) environmental-ecological impact and biological effects; and (3) economic issues, i.e., costs and benefits associated with the SSPS. The feasibility of the SSPS based on the parameters of the study was established.

Solar power generation with the pyroelectric effect

Abstract: It is shown with the help of a small‐signal model that the pyroelectric effect cannot be used for efficient generation of electrical power from solar radiation.

Space oriented microwave power transmission system

Abstract: A combined active phased antenna array for satellite solar power station systems includes a plurality of directly coupled microwave energy generators for conversion of the dc power generated by a system of solar energy conversion means to microwave energy. The microwave power is transmitted through space in a narrow beam for capture and rectification at the receiving point. The microwave energy generator devices embodied in the invention are of the crossed field amplifier type having a very high efficiency and extremely long life through the use of a cold cathode secondary emitting electron source. The microwave generated power is transmitted through slotted waveguide radiator arrays with the phase of the energy monitored and corrections are made by phase shifting devices where necessary.

Measurement of circumsolar radiation

Abstract: An instrument system has been developed to measure the flux of energy from the sun and the circumsolar region (the small-angle region around the sun) as a function of angle, wavelength, and atmospheric conditions. The measurements are necessary to accurately predict the performance of solar thermal conversion systems using focusing collectors, and to determine whether pyrheliometer data are adequate for estimating this performance. The instrument system consists of a "scanning telescope", several conventional solar instruments, and a digital electronics control and recording system. The telescope makes a scan of ±3°, passing through the center of the sun. The angular resolution is approximately 1.5 minutes of arc from the center of the sun out to two solar radii, and 5 minutes from there out to 3°. The background caused by direct solar light scattering within the telescope itself has been reduced to less than 1% of the intensity of the circumsolar radiation. Spectral dependence of the radiation is determined using filters. A measurement program using this telescope will be carried out at various locations in the West and Southwest. Additional instruments are being constructed for deployment for the accumulation of data at potential sites for future solar power plants.© (1976) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Dynamic conversion of solar generated heat to electricity

Abstract: The effort undertaken during this program led to the selection of the water-superheated steam (850 psig/900 F) crescent central receiver as the preferred concept from among 11 candidate systems across the technological spectrum of the dynamic conversion of solar generated heat to electricity. The solar power plant designs were investigated in the range of plant capacities from 100 to 1000 Mw(e). The investigations considered the impacts of plant size, collector design, feed-water temperature ratio, heat rejection equipment, ground cover, and location on solar power technical and economic feasibility. For the distributed receiver systems, the optimization studies showed that plant capacities less than 100 Mw(e) may be best. Although the size of central receiver concepts was not parametrically investigated, all indications are that the optimal plant capacity for central receiver systems will be in the range from 50 to 200 Mw(e). Solar thermal power plant site selection criteria and methodology were also established and used to evaluate potentially suitable sites. The result of this effort was to identify a site south of Inyokern, California, as typically suitable for a solar thermal power plant. The criteria used in the selection process included insolation and climatological characteristics, topography, and seismic history as well as water availability.

Feasibility of Large-Scale Orbital Solar/Thermal Power Generation

Abstract: This paper explores the feasibility of large-scale orbital solar/thermal power generation. For the large-scale orbital thermal plant the most important system parameters are transportation cost, weight of the solar concentrator and system component efficiencies. The thermal conversion concept discussed in this paper is potentially feasible with today's solar concentrator technology and component efficiencies if the low Earth orbit transportation cost is approximately $60/lb. The system is also potentially feasible with space shuttle transportation cost of approximately $160/lb and 1980 component efficiencies if the solar concentrator can be constructed at approximately 0.03 lb/ft. Large-scale collection of solar power in space for use on Earth has been discussed by several authors in the past five years. Typical schemes involve direct photovoltaic conversion to electricity, microwave conversion and transmission, and reconversion to electricity on Earth. This paper describes the alternative of heat engines for initial conversion. Significant economic leverage results from collecting the solar energy with a thin reflective film at a few cents per square meter. A Brayton cycle heat engine is utilized to convert thermal energy to electricity. Economic feasibility is dependent on system technical performance, transportation cost, and cost of alternative power sources.

Integrated power/attitude control system /IPACS/

Abstract: An integrated power and attitude control system (IPACS) for spacecraft is described. The system utilizes energy wheels for electrical energy storage as well as attitude control. Results from the feasibility studies of this concept are summarized and indicate potential weight and cost savings up to 30% over conventional power and control systems. The IP ACS advantage is particularly significant for the longer duration missions which have a large number of energy charge-discharge cycles and higher power requirements. A system for a shuttle-launched Research and Applications Module (RAM) free-flying observatory spacecraft is described. The system utilizes three gimbaled, control, and energy-momentum gyros in a planar array. Each gyro unit is rated at 2.4 kw and delivers 1095 w-hr of energy while maintaining control angular momentum above 1115 N-m-sec. Dynamic response of combined power and control functions was evaluated by digital simulations which included significant nonlinearities and a symmetrical energy distribution law. Simulation data indicate that spacecraft attitude control response is similar to that achieved without the superposition of energy wheel speed changes and is essentially uncoupled from that of the faster power control loop. Both power and control dynamics are well regulated. A NUMBER of spacecraft designs have been develxmoped for the missions of the shuttle era. Most of these require subsystems with lifetimes of 5-7 yr to meet cost effectiveness goals. Pointing requirements below 0.25° are common, with specific scientific missions requiring experiment pointing to 1 arc sec. Momentum storage devices normally are used to provide control torques for long-life missions where control thruster propellant weights and valve life test costs prove excessive. The choice of momentum storage is reinforced, or even required, in several missions where mass expulsion contaminants are prohibited by experiment viewing requirements or where fine pointing stability and slewing is required. The significant impact of the long-life requirement on the electrical power system design is in the sizing of components rather than in the type of system selected. This is because nearly all systems postulated utilize solar arrays for electrical power generation and secondary batteries for electrochemical energy storage. The batteries prove to be the heaviest components of advanced spacecraft solar power systems. The weight of the batteries is determined by the rated energy densities and their inherent characteristic of decreasing life with increased depth-of-discharge and charge-discharge rate. Thus, for a specific energy storage requirement, the designer's major option for increasing battery life is that of increasing the size or number of battery cells thereby decreasing the depth of discharge. As a result, batteries and their controllers commonly constitute 30-40% of an electrical power system weight. Developments of recent years1'2 have shown that flywheels designed to store energy can provide higher energy densities than can be expected from several conventional spacecraft electrochemical devices. In spacecraft applications, parity in energy density between the energy wheel and battery subsystems may result in significant advantage to the energy wheel system. This is because many spacecraft designs currently employ flywheels in momentum storage attitude control systems which approximate the weight of energy wheels.

Heat storage device

Abstract: A heat storage device of simple design and compact dimensions is disclosed The device uses a heat storage medium which contracts upon melting and which has a melting point high enough to be of use in connection with conventional, nuclear, and solar power plants

A solar/hydrogen economy

Abstract: A growing number of experts foresee an all-electric system with solar energy and hydrogen, separately or in tandem, playing important roles. Electric utilities are examining long-range possibilities of a power system in which hydrogen is centrally manufactured from water by electrolysis or other means, then pipelined at low transmission cost to individual user locations for generation of electricity or direct fuel use. Solar power systems, including orbital power plants whose energy is beamed to earth by microwaves, are assessed. (1 diagram, 1 photo)

Absorber for solar power.

Abstract: A simple, economical absorber utilizing a new principle of operation to achieve very low reradiation losses while generating temperatures limited by material properties of quartz is described. Its performance is analyzed and indicates approximately 90% thermal efficiency and 73% conversion efficiency for an earth based unit with moderately concentrated (~tenfold) sunlight incident. It is consequently compatible with the most economic of concentrator mirrors (stamped) or mirrors deployable in space. Space applications are particularly attractive, as temperatures significantly below 300 K are possible and permit even higher conversion efficiency.

Wind and solar power engineering

Abstract: : The need for small wind and solar powered installations for use at small settlements and installations is briefly discussed.

Utilization of space technology for terrestrial solar power applications

Abstract: A description is given of the evolution of photovoltaic power systems designed and built for terrestrial applications, giving attention to problem areas which are currently impeding the further development of such systems. The rooftop testing of surplus solar panels is considered along with solar powered seismic observatories, solar powered portable radio sets, and design considerations identified from past experience. Present activities discussed are related to a solar powered on-shore beacon flasher system, a solar powered buoy, and a solar powered beacon flasher buoy.

Sources of energy

Abstract: Publisher Summary This chapter discusses the sources of energy in use today—waterpower, fossil fuels, and nuclear fuels along with other sources that hold some hope for the future. The ultimate source of almost all the energy that is used today is radiant energy from the sun. All of our chemical fuels, wood, coal, oil, and natural gas, are derived from plant and animal life that grew because of the action of sunlight. The most important source of energy that is not derived directly from the sun is stored in nuclei and can be released through fission and fusion. Some other sources of nonsolar energy, such as geothermal and tidal energy, are also present but they are of little importance at present. In the future an increasing fraction of the world's energy will be obtained from nuclear fission reactors, and hopefully, during the next century, fusion reactors will be available to take over the major burden of energy production. Although the direct use of solar energy now appears to be a very costly operation, improved techniques can eventually reduce the costs relative to other sources and make solar power an important part of the overall energy picture. The widespread use of geothermal energy depends on how well new technological methods are developed.