Design and analysis of a BIPV/T system with two applications controlled by an air handling unit

Abstract

A building integrated photovoltaic thermal (BIPV/T) system was designed and analyzed. The BIPV/T system is composed of multiple PV/T air collectors integrated into the building facade and connected to an air handling unit (AHU) to control the air flow. The system operates with two applications, an application for cold weather and an other for hot weather. In cold weather, the BIPV/T system recovers heat from the PV modules to preheat the outdoor fresh air. While in hot weather, the cool air exhausted from the conditioned spaces of the building is used to decrease the PV cells temperature, instead of ambient air as in conventional PV/T air collectors. An experimental tests were conducted to see the effect of using the cool exhaust air as coolant for the PV cells instead of ambient air. In order to predict thermal and electrical performance of each PV/T air collector under real climatic conditions, a theoretical model of a single pass PV/T air collector was developed and validated against experimental observations from previous literature. The theoretical and experimental comparison between the case of using exhaust air as coolant and the case of using ambient air as coolant showed an important decrease in PV cells temperature. The maximum decrease value in PV cells temperature obtained from the simulation is 9.46°C in a selected day from August, while the electrical simulation showed that the average increase value in electrical efficiency in a selected day from August is 0.350. The simulation of the BIPV/T system in cold weather indicated that the average rate of saved useful thermal energy when using preheated outdoor fresh air in a selected day from February is 24.20%. Furthermore, the PV/T air collector performances were compared for the optimal tilt angle and the complete vertical position. The results revealed that installing the PV/T air collector at optimal tilt angle showed much better performances than a one installed at a complete vertical position, especially the electrical performance in Summer.