Modeling of concentrating photovoltaic and thermal systems

Abstract

An energy balance model for concentrating photovoltaic and thermal (CPVT) systems is presented. In the model, the CPVT system and its environment are represented using a set of input parameters. The main outputs of the model are the system's electrical and thermal efficiencies. The model accounts for optical losses. Thermal losses are derived from a thermal network model of the hybrid receiver. The solar cell performance is modeled as a function of the temperature and the irradiance. The robustness of the model is demonstrated by a sensitivity analysis of all input parameters. The influence of the operating temperature on the electrical and thermal performances and the overall efficiency of the CPVT system are discussed. The limiting cases of maximum electrical and thermal power outputs are presented. Further, the influence of the concentration ratio on the electrical and thermal performance and on the partitioning of these two power outputs is analyzed in detail. It is shown that high concentration reduces the thermal losses considerably and increases the electrical efficiency. At concentration ratios above 300, the system operates with an overall efficiency of 75% at temperatures up to 160 °C. Copyright © 2012 John Wiley & Sons, Ltd. An energy balance model for concentrating photovoltaic and thermal systems is presented and applied to investigate the influence of operating temperature and concentration ratio on the hybrid performance, that is, the electrical and thermal efficiencies. It is shown that high concentration offers several advantages to a hybrid photovoltaic and thermal system. As the concentration increases, the electrical efficiency also increases and, at the same time, thermal losses are reduced significantly, enabling overall conversion efficiencies of 75% at operating temperatures up to 160 °C. © 2014 John Wiley & Sons, Ltd.