Engineering topics

Mills, M. W.

Publications and source records attributed to Mills, M. W..

4 records

NASA NTRS1985

Estimating the Performance of a Concentrating Solar Array

Comprehensive mathematical-analysis technique developed for array of solar-photovoltaic panels equipped with truncated-pyramid concentrators. Hollow pyramidal concentrator reflects Sunlight onto panel of photovoltaic cells. Comprehensive optical, thermal, and electrical analysis performed on array of units. Technique applicable, with modifications, to analysis and design of other multiple-cell reflecting photovoltaic systems.

French, E. P.↗

NASA NTRS1985

Tests of Low-Concentration-Ratio Photovoltaic Elements

Report describes performance measurements on elements of low-concentrationratio solar arrays (LCRSA's) employing silicon and gallium arsenide photovoltaic cells. Measurements intended to verify predictions of performance based on mathematical models. Measured and predicted values found to agree closely for both normal and off-normal pointing of array toward Sun.

Mills, M. W.↗

NASA NTRS1984

Performance measurement of low concentration ratio solar array for space application

The measured performance of a silicon and a gallium arsenide low concentration ratio solar array (LCRSA) element is presented. The element characteristics measured in natural sunlight are off pointing performance and response to mechanical distortions. Laboratory measurements of individual silicon and gallium-arsenide solar cell assemblies are also made. The characteristics measured in the laboratory involved responses to temperature and intensity variations as well as to the application of reverse bias potentials. The element design details covered include the materials, the solar cells, and the rationale for selecting these specific characteristics. The measured performance characteristics are contrasted with the predicted values for both laboratory testing and high altitude natural sunlight testing. Excellent agreement between analytical predictions and measured performance is observed.

Mills, M. W.↗

NASA NTRS1983

Optical, thermal, and electrical performance of low-CR solar arrays

This paper describes the analysis and testing of a photovoltaic low-CR concentrator shaped like a truncated pyramid with an aperture of 0.5 m on a side and a geometric concentration ratio of six. The truncated base plane is covered by either silicon (Si) or gallium arsenide (GaAs) solar cells. Ray-trace analysis of the concentrator predicts a peak optical efficiency of 0.77, which falls off only gradually with pointing error. A coupled thermal-electrical analysis of the system shows that the moderately nonuniform illumination produced by the concentrator does not result in significant mismatch losses, provided the solar cells are connected in parallel groups. The results of ground tests involving a full-scale prototype concentrator conform well with theoretical predictions.

French, E. P.↗