4 Matching Results

Search Results

Photovoltaic module soiling studies, May 1978-October 1980

Description: The retention of particulate contamination on the surface of flat-plate photovoltaic devices is adversely affecting electrical performance of outdoor-exposed modules. The results of an experimental study being performed by the Jet Propulsion Laboratory's Low-Cost Solar Array Project to characterize and understand the effects of outdoor contaminants on sensitive optical surfaces of flat-plate photovoltaic modules and cover materials are described. Comparative electrical and optical performance data from photovoltaic modules and materials subjected to outdoor exposure at field test sites throughout the United States have been collected and examined. The results show significant time- and site-dependence. During periods when natural removal processes do not dominate, the rate of particulate contamination accumulation appears to be largely material-independent. The effectiveness of natural removal processes, especially rain, is strongly material-dependent. Glass and acrylic top-cover materials retain fewer particles than silicone rubber does. Side-by-side outdoor exposure testing for long duration is presently the most effective means of evaluating soiling differences between materials. Changes in spectral transmission as a function of time and location and limited scattering data are presented.
Date: November 1, 1980
Creator: Hoffman, A.R. & Maag, C.R.
Partner: UNT Libraries Government Documents Department

Proposed method for determining the thickness of glass in solar collector panels

Description: An analytical method has been developed for determining the minimum thickness for simply supported, rectangular glass plates subjected to uniform normal pressure environmental loads such as wind, earthquake, snow, and deadweight. The method consists of comparing an analytical prediction of the stress in the glass panel to a glass breakage stress determined from fracture mechanics considerations. Based on extensive analysis using the nonlinear finite element structural analysis program ARGUS, design curves for the structural analysis of simply supported rectangular plates have been developed. These curves yield the center deflection, center stress and corner stress as a function of a dimensionless parameter describing the load intensity. Results are included for plates having length-to-width ratios of 1, 1.5, 2, 3, and 4. The load range considered extends to 1000 times the load at which the behavior of the plate becomes significantly nonlinear. Over the load range analyzed, the analysis shows that the ratio of center deflection to plate thickness for a plate of length-to-width ratio of 4 is less than 70 to 1, whereas linear theory would predict a center deflection about 1200 times the plate thickness. The stress is also markedly lower than would be predicted by linear theory. These analytical results show good agreement with the analytical and experimental work of others.
Date: March 1, 1980
Creator: Moore, D.M.
Partner: UNT Libraries Government Documents Department

Price allocation guidelines January 1980: Low-cost solar array project

Description: The price allocation guidelines (PAG) are an integrated set of specific cost targets for several task areas within the Low-cost Solar Array (LSA) Project. PAG is a working tool of LSA Project management designed to provide consistent and meaningful guidelines for costs of polycrystalline silicon material, sheet, cells, encapsulants, and module manufacturing. It is expected that advanced photovoltaic concepts derived from industry and the research community can be developed so that it will be possible by the end of 1982 to demonstrate production processes, all process steps, and prototype equipment required to manufacture flat-plate photovoltaic modules. This demonstration would incorporate production rates and product quality consistent with a specific market price determined by the program. This stage of development has been referred to as Technical Readiness. A goal of $0.70 per peak watt (1980 dollars) has been established for the cost of electricity generated by photovoltaic modules. The processes for producing modules demonstrated to be technically ready must be amenable to scale-up so that this price goal can eventually be achieved in the marketplace. The guidelines described in this document allocate portions of that goal to each module component. Sheet materials derived from the following five technologies are considered: Czochralski, heat exchanger method (HEM), edge-defined film growth (EFG), dendritic web, and silicon on ceramic (SOC). Each type of material provides a unique combination of projected silicon yield, cell efficiency, and module packing efficiency. Also included are tables describing actual inflation rates from 1975 to 1979, and projected inflation rate to mid-1980. Project goals are now expressed in 1980 dollars rather than 1975 dollars, and these tables enable conversion of dollar amounts from prior years (1974 to 1980) to their 1980 or 1975 equivalents.
Date: January 15, 1980
Creator: Aster, R. W.
Partner: UNT Libraries Government Documents Department

Progress Report 16 for the period April-September 1980, and the proceedings of the 16th Project Integration Meeting

Description: Progress made by the Low-Cost Solar Array Project during the period April to September 1980, is reported in detail. Progress on project analysis and integration; technology development in silicon material, large-area silicon sheet and encapsulation; production process and equipment development; engineering, and operations is described. A report on, and copies of visual presentations made at, the Project Integration Meeting held September 24 and 25, 1980 are included.
Date: January 1, 1980
Creator: McDonald, R.R.
Partner: UNT Libraries Government Documents Department