Performance improvement of a naturally ventilated building integrated photovoltaic system using twisted baffle inserts

Abstract

Building integrated photovoltaic (BIPV) systems constitute a key concept for the realization of sustainable buildings. However, these systems have limited efficiency and durability due to their insufficient cooling capabilities. To overcome this drawback, it is necessary to maintain the operating temperature as low as possible. This study investigates the effectiveness of a passive low-cost strategy to improve the photovoltaic module (PV) performance of naturally ventilated BIPV systems by decreasing the module operating temperature. This strategy consists of inserting twisted baffles on the rear side of a PV module to enhance its cooling performance. A numerical investigation was performed using Computational Fluid Dynamics (CFD) simulations in order to explore the module surface temperature and its electrical efficiency. The effects of solar irradiance, the number and position of twisted baffles, and twist ratio have been investigated. The results revealed that the average temperature of the PV surface decreases with the increase of the number of twisted baffles (N), which leads to an improvement in the electrical efficiency. Indeed, the optimum performance enhancement is attributed to N = 15, and the corresponding PV temperature was decreased from 312.66 K to 310.15 K and from 348.42 K to 342.64 K for a solar irradiance variation from 200 to 1000 W.m-2, resulting in an improvement of 1.21–3.36% in electrical efficiency compared to the case without inserts. Concerning the effect of the twist ratio, it is shown that the optimum electrical efficiency improvement is reached for the lowest twist ratio, which is in the range of 1.7–6.1% for solar irradiance range from 200 to 1000 W.m-2.