摘要： A building integrated photovoltaic (BIPV) system can be installed at optimum tilt and orientation angle to maximize the electrical output. PV output is negatively correlated with the increase in the PV panel temperature. This paper aims at investigating the influence of water flow over the BIPV roof of a two-storied single-family house on the performance of the proposed optimally tilted semi-transparent BIPV thermal system having different facing directions. The periodic nature of insolation, ambient air temperature, BIPV cell temperature, slab temperature, water flow temperature and room temperature have been considered while solving energy equilibrium differential equations. The insolation values used in the energy equilibrium equations are computed employing periodic HDKR (Hay, Davies, Klucher and Reindl) model, which is based on anisotropic sky concept. Results indicate that the average BIPV cell temperature is reduced annually by approximately 10 °C and efficiency is enhanced by 6% when a water flow rate of 1.1 kg s?1 is provided over the BIPV roof. It is also observed that on the most critical day of the year, the temperature of outlet water is 11.5 °C higher than that of inlet water temperature which resulted in 4 kW extraction of exergy.