Performance investigation on an agricultural photovoltaic thermal system based on spectral separation

Abstract

Based on cascade utilization of full spectrum solar energy, a spectral splitting agriculture photovoltaic thermal hybrid system has been proposed in this study. The red and blue light is assigned to farmland for plant photosynthesis, while the photovoltaic active light is absorbed by solar cell for electricity generation, and the rest to thermal receiver for high temperature production. To maximize the power output of proposed system, redundant waste heat is recovered through ejector and converted into electricity in organic Rankine cycle subsequently. By such incorporation, the proposed system can not only increase the overall utilization efficiency of solar energy, but also achieve the cogeneration of crops and electricity on the same land. Energy, exergy, and economic analyses are performed to evaluate the performance of proposed system. Results show that the overall utilization efficiency of solar energy reaches 39.67 % with the highest losses of 79.65 MW in organic Rankine cycle. From the point view of exergy, photoelectric conversion in solar cell is responsible for the largest exergy destruction and finally the overall exergy efficiency of proposed system reaches 40.65 %, which is 16.13 % higher than that of equivalent agricultural and photovoltaic system with separate land use.