Performance of ventilated double-sided PV facade compared with conventional clear glass facade

The outdoor performance of a naturally ventilated double-sided PV facade was evaluated through field monitoring from a small scale test rig. The comparison of its thermal performance with that of a conventional clear glass façade with shield was made through the field measurement. The measured data show that the maximum indoor air temperature for conventional facade is close to 34 °C, while 29 °C only for PV façades under same summer weather conditions. This indicates that heat gain to building in summer could be substantially reduced and additional electrical power could also be generated from such façade as a byproduct. In addition, the temperature influence on thin-film solar cells was tested. The effect of temperature on the conversion efficiency of thin-film amorphous silicon solar cell is found small. It is observed that a reduction of 15.6 °C in module temperature of the thin-film solar cell only leads to a decrease of 0.29% in conversion efficiency. However, the ventilation cooling of PV reduce the possibility of potential overheating problems when PV is integrated into building as an external façade, especially in extreme hot weather conditions. In addition, the internal heat gain could be considerably reduced compared with conventional clear glass façade with shield in summer. A better thermal comfort of indoor occupants thus could be anticipated in the present proposed façade system.