Energy saving in buildings by using the exhaust air and phase change material for cooling of photovoltaic panels

Abstract

Two air-type Photovoltaic Thermal (PVT) systems with and without Phase Change Material (PCM) were numerically investigated to evaluate the effect of using PCM as coolant on the air output temperature, amount of preheating temperature difference, the useful thermal and electrical power of the system as well as the participation of PVT/PCM system in supplying the typical required thermal load of the outside air (PEC). Based on the results, the PCM cooling decreases the PV temperature by 1.86–8.8 °C and 5.61–16.37 °C for 15 Jan and 15 Aug, respectively. In addition, the PCM causes to increase the PVT output air temperature rises by 2.96 °C even after sunset for 15 Jan. Moreover, the PVT system with surface area of 1.8 m2 produces 45.46–95.68 kWh useful thermal energy in the cold months. Besides, the monthly electricity generation rate of the system was obtained as 51.04–186.63 kWh. Moreover, the average PEC of the system was obtained as 66.86% for 12 months of the year. Also, PEC was obtained higher than 100 for two months of the year. Besides, the average monthly PEC increases with air mass flow rate to 0.5 kg/s due to increasing the electrical and thermal power of the system. However, for the higher air mass flow rates, the fan power escalates with increasing the air mass flow rate and diminishes the average PEC.