A comparative experimental investigation of CPV with and without SOE
Solar radiation in Thailand is abundant. Unfortunately, there is a large amount of non-direct solar radiation that could not be utilized by high concentrating photovoltaic (CPV) systems. This paper investigates the effect of diffuse radiation on a Fresnel-based CPV system using a secondary optical element (SOE) made of flat plate reflectors operating in Thailand. Physical experiments were conducted by constructing a simple SOE attached to commercial CPV components. Experimental results showed that the efficiency of the system with an SOE increased at least 10%. This increase in system efficiency is more significant with increasing diffuse solar radiation, i.e. the efficiency increased by 11-23% when the diffuse radiation ratios were 0.1–0.4, respectively. In a continuous operation, the energy gain from a CPV system with an SOE was 20% higher than the conventional system.