The option of phase change materials as temperature regulation for building integrated photovoltaics

Abstract

The performance of photovoltaic modules outdoors suffers from attained high temperatures due to irradiation as a result of the negative temperature coefficient of their efficiency. Phase change materials (PCMs) are investigated as an option to regulate photovoltaic module temperature and thereby reduce its electrical efficiency decrease. Experimental set-ups have been studied by Huang et al. and Hasan et al. [1; 2; 3; 4], which showed significant improvements in the temperature regulation of building integrated photovoltaics (BIPV). In this study a simplified heat balance model is used to calculate the extra energy gain such a PV/PCM system can bring on a yearly basis. It is shown that on average an increase of 1-3% of the total energy output can be expected for several commercially available PCMs. However, when taking into account the PCM material cost this shows no economic potential for the future. For an acceptable payback period of 10-20 years the storage capacity of a PCM would require an increase in the range of one order of magnitude, which is not realistic. Further options might come from a combination with building climate control in which the PCM plays a double role controlling the PV temperature as well as the inside climate temperature.