Design and optical analysis of a non-ideal parabolic trough concentrator for uniform flux distribution in photovoltaic applications

Concentrating photovoltaic (CPV) systems utilize optical elements to focus sunlight onto small-area solar cells. Among different concentrators, Parabolic trough concentrators (PTCs) have simple design and offer medium concentration ratios (typically 30–100 × ). But PTCs are line focus and their spatial non-uniform flux distribution limit their use in CPV applications. This study presents a geometric redesign of conventional PTCs, transforming their line focus into a spatially uniform focus and referred as a segmented non-ideal parabolic trough concentrator (NI-PTC). A numerical model is developed and validated. The validated model is used to investigate performance of NI-PTC by varying design parameters such as concentration ratios, geometrical losses, rim angles, and sun's half acceptance angle. It is found that the flux distribution stays uniform across the photovoltaic cell in the range of 98.6% and 99.1% regardless of concentration ratio (20–60 × ). The geometric losses vary from 7.7% to 9.6%, which is due to the rays not received by the receiver. Furthermore, we quantify the trade-off between rim angle and geometrical losses, showing that larger rim angles increase geometric losses. The geometric losses rose from as low as 0.1% at 5° to 13.6% at 60° while maintaining flux uniformity. The flux uniformity of NI-PTC design is found to be independent of sun half-acceptance angle (0.53°).