Design, simulation and experimental characterization of a novel parabolic trough hybrid solar photovoltaic/thermal (PV/T) collector

Abstract

A novel hybrid solar concentrated photovoltaic thermal (PV/T) collector is designed, simulated, and tested. The PV/T system uses a parabolic trough to focus sunlight towards a nonimaging compound parabolic concentrator (CPC) that is formed of single junction Gallium Arsenide (GaAs) solar cells to simultaneously generate electricity and high temperature thermal power. The GaAs cells generate electricity from high energy photons and reflect low energy photons towards the high temperature absorber, thus maximizing the exergy output of the system. The two-stage design also allows the thermal absorber to reach a geometric concentration ratio of ∼60×, which is significantly higher than other PV/T systems and enables the absorber to reach high temperatures even under partial utilization of the solar spectrum. The modelled exergy efficiency with a thermal absorber operating at 500 °C is 37%. In the experimental setup, the maximum outlet temperature reached was 365 °C with a thermal efficiency of around 37%. The direct solar to electric efficiency from the GaAs cells was 8%. This design is capable of producing electricity directly along with high temperature thermal energy that can be stored for dispatchable electricity production and has the potential to significantly improve the exergy efficiency of parabolic troughs plants.