Experimental Performance Evaluation of a BIPVT Roof Tile System

Building-integrated PV can greatly extend the potential installation capacities of building façades and roof covers. However, integrating PV into buildings has a decisive disadvantage regarding the performance of solar cells: Because there is no rear ventilation compared to standard rooftop PV modules, the solar cells show lower performance due to elevated module temperatures. Combining these systems with solar thermal systems results in a hybrid system. In this work, a performance evaluation of an improved hybrid solar roof tile that has the characteristics of a standard roof tile and thus can replace the building envelope is presented. Therefore, the examined system is compared to a standard rooftop PV system by using performance ratio metrics. These systems are installed on two identical roof structures in Cologne, Germany, and measured continuously in 20-second intervals. The system is actively rear-ventilated in order to decrease module temperature and utilize the pre-heated ambient air for a heat pump system. The results of the performance ratio calculation for a period of 9 months show only slightly lower average values of 1.1% for the solar roof tiles. The results show a relative improvement between 9%rel and 14%rel compared to the values of building-integrated systems found in the literature.