On the potential of solar cells to efficiently operate at high temperature

The development of high temperature CPV/thermal (CSP) hybrid systems appears to be a promising route to improve the overall solar to electricity conversion efficiency. Moreover, such systems would not only use the residual heat stemming from the unconverted fraction of the incident solar radiation in PV cells, but they would also provide the advantage of storing energy as heat. However, the performances of such hybrid systems depend strongly on the temperature of the thermal receivers which are only effective at high temperatures (typically above 250°C) while solar cells typically operate at temperatures close to ambient. An appropriate strategy is to make PV cells efficiently operate at temperature levels significantly exceeding the normal range of temperatures for which they are commonly designed. The degradation of electrical performance associated with high working temperature is less pronounced when the cell is submitted to high sunlight concentrations. An efficient photovoltaic conversion at temperature levels exceeding the ambient may however require significant modifications in the architecture of the cells. In this work, we assessed the feasibility of this strategy by studying the electrical properties as well as the overall efficiency of the PV/CSP system at different temperatures and sunlight illuminations.