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 ~60X, 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 ºC 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.

No abstract

A novel double stage high-concentration hybrid solar photovoltaic thermal (PV/T) collector using nonimaging optics and world record thin film single-junction gallium arsenide (GaAs) solar cells has been developed. We present a detailed design and simulation of the system, experimental setup, prototype, system performance, and economic analysis. The system uses a parabolic trough (primary concentrator) to focus sunlight towards a secondary nonimaging compound parabolic concentrator (CPC) to simultaneously generate electricity from single junction GaAs solar cells, as well as high temperature dispatchable heat. This study is novel in that the solar cells inside the vacuum tube act as specular mirrors for lower energy photons to maximize the system exergy, and (b) secondary concentrator allows the thermal component to reach a concentration ratio ~60X, which is significantly higher than conventional PV/T concentration ratios. The maximum outlet temperature reached was 365ºC, and on average the thermal efficiency of the experiment was around 37%. The maximum electrical efficiency was around 8%. The total system electricity generation is around 25% of incoming DNI, by assuming the high temperature stream is used to power a steam turbine. The installed system cost per unit of parabolic trough aperture area is $283.10 per m 2 .

No abstract

No abstract