Analysis and optimization of passive cooling approach for free-standing photovoltaic panel: Introduction of slits

One of the major issues related to market available silicon based photovoltaic (PV) technologies is the performance drop caused by relatively high PV panel operating temperatures. The proper cooling of PV panels can reduce performance degradation and increase the lifetime of convectional PV panels. This paper investigates architecture modifications to market available silicon PV panels with the introduction of slits on the PV panel surface, which enables the passive cooling of PV panels. Two different arrangements of slits were numerically investigated and followed with the optimization approach. A developed numerical model was derived from the referent numerical model that was experimentally validated. For each considered scenario, a detailed flow and thermal analysis was performed which included optimization regarding minimum average PV cell temperatures. The considered slit types differ with slit orientation, i.e. parallel to PV panel tilt-axis (type-A) and perpendicular to PV panel tilt-axis (type-B). In both cases, a detailed analysis and optimization required similar to 100 CFD simulations to investigate the effects of different slit sizes and all wind directions. Overall, using the considered slit modifications, the average PV cell temperature could be decreased up to 3 degrees C, where effective cooling with the proposed modification is only reasonable for wind speeds up to 5 m/s.