Periodic theory of building integrated photovoltaic thermal (BiPVT) system

•We develop a periodic model for rooftop BiSPVT based on energy balance equations.•We examine hourly room air temperatures and temperature distribution inside roof.•Optimum roof thickness observed was in between 0.30 and 0.40 m.•Due to thermal heating, temperatures reach thermal comfort range of 20–23 °C.•Room 1 can be used for crop drying as temperatures are high.

In this paper, a periodic analysis of photovoltaic integrated Sodha BERS Complex has been developed. Based on energy balance equation of semitransparent photovoltaic roof, room air, reinforced concrete cement (RCC) roof of second floor of Sodha BERS Complex and second floor room air, a matrix (5 × 5) has been developed by applying the concept of Fourier coefficients to evaluate unknown constants. For known constants, hourly variation of room air temperatures and temperature distribution as a function of thickness of roof have been obtained for a given climatic and design parameters. Computations have been carried out for a typical day of winter at Varanasi and the results have been experimentally validated for the bare roof. Further, the decrement factor (f) and thermal load leveling (TLL) of building have also been evaluated for thermal comfort. Effect of number of air changes per hour through the room on room air temperature, decrement factor and thermal load levelling has also been studied.