A linear concentrator photovoltaic module: analysis of non-uniform illumination and temperature effects on efficiency
✍ Scribed by F. Chenlo; M. Cid
- Publisher
- Elsevier Science
- Year
- 1987
- Weight
- 656 KB
- Volume
- 20
- Category
- Article
- ISSN
- 0379-6787
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✦ Synopsis
A concentrating photovoltaic system has been built that uses Fresnel lenses of a potentially low cost design, and which employs a simple and robust method for bonding solar cells to the cooling tube. The lenses are a glass-ethyl vinyl acetate hybrid, and the cells are bonded to a copperalumina-copper sandwich with soft solder.
The performance of the prototype system, based on measurements, was evaluated as giving an overall efficiency of 10.2% at beam radiation of 890 W m -2, and an inlet water temperature of 28 °C.
The advantages of the hybrid lens compared with those of a methacrylate lens are explained. We estimate the optical efficiency of a prototype of this lens as 76% at 30× concentration on a receiver 2 cm in width.
The cell mounting has proved to be durable, easy to fabricate, and to have low thermal resistance (0.8 °C cm 2 W-l), surface electrical resistance (0.1 m~2/[::]) and hydraulic resistance (1180 N m-: per metre).
This article concludes with a description and results of two theoretical models used to study the performance of the concentrating module under conditions of non-uniform illumination and temperature. A finite element thermal model calculates cell and mounting temperature profiles as a function of the illumination profile, and a cell electrical model gives cell output as a function of illumination, temperature, cell type and metallization grid. The models illustrate the fact that system losses are higher from the combined effects of non-uniform illumination and temperature, than from the sum of both effects taken independently.