Regulating the temperature of building integrated photovoltaics (BIPV) using phase change materials (PCMs) reduces the loss of temperature dependent photovoltaic (PV) efficiency. Five PCMs were selected for evaluation all with melting temperatures similar to 25 +/- 4 degrees C and heat of fusion between 140 and 213 kJ/kg. Experiments were conducted at three insolation intensities to evaluate the performance of each PCM in four different PV/PCM systems. The effect on thermal regulation of PV was determined by changing the (i) mass of PCM and (ii) thermal conductivities of the PCM and PV/PCM system. A maximum temperature reduction of 18 degrees C was achieved for 30 min while 10 degrees C temperature reduction was maintained for 5 h at -1000 W/m(2) insolation. (C) 2010 Elsevier Ltd. All rights reserved.