A high-efficiency hybrid high-concentration photovoltaic system

Abstract

Photovoltaic power generation is a growing renewable primary energy source, expected to assume a major role as we strive toward fossil fuel free energy production. However, the photovoltaic efficiencies limit the conversion of solar radiation into useful power output. Hybrid systems extend the functionality of concentrating photovoltaics (CPV) from simply generating electricity, to providing simultaneously electricity and heat. The utilization of otherwise wasted heat significantly enhances the overall system efficiency and boosts the economic value of the generated power output. The current system consists of a scalable hybrid photovoltaic-thermal receiver package, cooled with an integrated high performance microchannel heat sink. The package can be operated at elevated temperatures due to its overall low thermal resistance between solar cell and coolant. The effect of the harvested elevated coolant temperature on the photovoltaic efficiency is investigated. The higher-level available heat can be suitable for sophisticated thermal applications such as space heating, desalination or cooling (polygeneration approaches). A total hybrid conversion efficiency of solar radiation into useful power of 60% has been realized. The exergy content of the overall output power was increased by 50% through the exergy content of the extracted heat. An analysis based on the economic value of heat illustrates that the reused heat can double the economic value of such a system.