Performance Enhancement of a Water Cooled BIPV System
Monia Chaabane1*, Salma Benzarti1, Hatem Mhiri1 and Philippe Bournot2
Published: October 04, 2022
Building-integrated photovoltaic systems (BIPV) currently represent a fundamental concept for the realization of sustainable buildings. However, these systems like any photovoltaic device are endowed with a limited efficiency due to the negative effect of the rise in the temperature of the cells. To limit this inconvenience, a cooling system must be applied. In this study, a suitable geometry was considered based on the temperature distribution in the base system. Indeed, a particular cooling system with a contact surface and a volume of water which increase as the temperature of the photovoltaic cells increases is considered. In addition, the external heat exchange surface of the proposed system is varied, linear and cylindrical based surfaces are studied.Numerical simulations were performed using the CFD package, Ansys. The main attention was focused on the overall system’s temperature and electrical efficiency improvement. Moreover, the gain generated in thermal energy is evaluated. The results revealed that the proposed system allows an important reduction of the PV cell temperature. While the non-cooled BIPV system temperature variation was in the range of 312.5 K - 348.5 K for a solar radiation ranging from 200 W/m2 to 1000 W/m2, this variation is reduced to small values for the water cooled system, respectively from 301 K to 310.5 K. This reduction in the temperature of the PV cells has directly resulted in an improvement in the photovoltaic efficiency of the system where a minimum average value of 15% has been noted, while the values noted for the uncooled system vary between 12.3% and 14.8% in depending on the incident radiation. Concerning the effect of the external heat exchange surface, the effect was not remarkable on the electrical performance of the system, however, the linear surface-based system proved to be more efficient in terms of thermal production than the cylindrical one. Finally, the effect of the flow rate is also discussed and the results show that for a relatively high value like 0.22 kg/s, a good reduction in the temperature of the PV cells can be achieved while ensuring a significant thermal production.
Keywords: BIPV; adapted geometry; Computational Fluid Dynamics (CFD); performance improvement