Optical and electrical performance investigation of truncated 3X non-imaging low concentrating photovoltaic-thermal systems

Abstract

Compound Parabolic Concentrators (CPC) have non-uniform distribution of flux when integrated to a Photovoltaic-Thermal (PVT) module. The non-uniform distribution of flux deteriorates the electrical and thermal performance of the solar panel. To reduce this effect, optimized homogenizers are integrated to CPC of concentration ratio 3X truncated to 2.5X and 2X. The study aims to demonstrate the effect of integration of homogenizer on the electrical performance of the system. Optical simulations carried out for full scale model (1 m × 2 m solar PVT panel area) with homogenizers, referred as Elongated Compound Parabolic Concentrators (ECPC), showed a reduction in the peak local concentration of 55% and 66% for the 2.5X and 2X cases at normal angle of incidence. Optically coupled electrical simulations are carried out, which are further validated using a scaled down prototype tested under solar simulator. The experimental results show peak electrical efficiency of 13.9% (2X) and 13.6% (2.5X) for CPC and 14.1% (2X) and 13.9% (2.5X) for ECPC. Further, benefits of homogenizer are evident near half acceptance angle, when improvement in electrical efficiency by ~23 ± 2% and ~37 ± 2% is observed for ECPC of concentration ratio 2X and 2.5X in comparison to CPCs of similar configuration. In addition, the effect of temperature on electrical performance has also been studied by conducting experiments for actively cooled and uncooled condition. A reduction in 10% electrical efficiency is reported for uncooled condition compared to actively cooled condition.