Thermal performance of passive photovoltaic-phase change material cooling systems: Experimental and numerical analysis of fin and panel inclination angles

초록

Excessive heat accumulation in photovoltaic (PV) panels reduces power generation efficiency by 0.2 similar to 0.5 % per degrees C increase in temperature, underscoring the need for effective passive cooling strategies. This study investigates a PV-phase change material (PCM) cooling system that employs internal aluminum fins to enhance natural convection within paraffin-based PCM (Parafol 18-97). A polyimide film heater was used to simulate solar heating, while thermocouples and Arduino-based acquisition recorded temperature at multiple points. Heat loss tests verified system reliability, and phase change dynamics were visually monitored with a digital camera. Complementary computational fluid dynamics (CFD) simulations were performed using a two-dimensional enthalpy-porosity and volume of fluid (VOF) model validated against experiments, which showed temperature deviations below 2 %. Parametric studies varying photovoltaic tilt angles (beta = 20 degrees similar to 90 degrees) and fin inclinations (alpha = -20 degrees to 20 degrees) revealed that the cooling performance was governed by the interaction between vertical convection layers and stagnant zones. A newly proposed surface cooling efficiency (SCE) index demonstrated that fins inclined at alpha = - 10 degrees improved cooling performance by up to 18 % compared with the horizontal fins, while alpha = 0 degrees was optimal at beta = 50 degrees similar to 70 degrees. The study identifies a critical geometric condition (alpha + beta >= 50 degrees) that activates strong vertical convection and maximizes heat transfer. These findings establish quantitative design guidelines for fin geometry and panel inclination, thereby advancing the practical development of high-efficiency passive PV cooling systems.

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