Abstract

The modern multi-junction concentrating solar cell is an emerging technology that is expected to play a crucial role in achieving solutions to energic and environmental challenges that the world faces today. A potential technical limit to widespread adoption of this technology is the degradation of solar cell efficiency at high operating temperatures. In this paper, a numerical heat transfer model is presented and applied to determine the effects of non-uniform incident illumination on the operating temperature of a triple-junction solar cell. Results show that even at quite low solar concentrations, maximum solar cell temperature significantly increased in the presence of non-uniform incident light, causing hot spots in some portions of the cell. Thus, a conventional cooling system, such as a plain channel, is insufficient for operating solar cells at reasonable temperatures under non-uniform illumination. However, the non-uniformity of the incident radiation has no effect on bulk fluid temperature and collected thermal energy at the duct exit.

Key words: Concentration solar cell; non-uniform illumination profile; active cooling; conjugate convection; surface radiation