Enhanced Efficiency in a Coupled Photovoltaic/Thermal Concentrating Solar Collector

We present an analysis of combined efficiencies in a coupled photovoltaic/thermal concentrating solar collector. The calculations take into account the drop in efficiency that accompanies the operation of photovoltaic cells at elevated temperatures along with a detailed analysis of the thermal system including all losses. An iterative numerical scheme is described that involves a coupled electro-thermal simulation of the solar energy conversion process. In the proposed configuration losses in the photovoltaic cell due to reduced efficiencies at elevated temperatures and the incident solar energy below the PV bandgap are both harnessed as heat. This thermal energy is then used to run a thermodynamic power cycle. The simulations show that it is possible to optimize the overall efficiency of the system by variation of key factors such as the solar concentration factor, band gap of the photovoltaic material, and the system thermal design configuration.