Enhancing the performance of air-based photovoltaic / thermal (PV/T) heaters using baffles and metal foam

Abstract

Photovoltaic/thermal (PV/T) heaters simultaneously produce electricity and heat, offering a promising solution to energy shortages and pollution. However, air's low thermal capacity limits its cooling effectiveness on PV modules, reducing overall PV/T performance. To overcome this, we performed numerical simulations to assess the combined impact of corrugated baffles and metal foam on the thermal and electrical performance of air-based PV/T heaters. A user-defined function (UDF) correlated module temperature with electrical efficiency, and model accuracy was confirmed against benchmark temperature and pressure-drop data. We examined the effects of mass flow rate (0.0116–0.0696 kg/s), metal foam configuration, and foam thickness on heater performance, and elucidated the foam's heat-transfer enhancement mechanism. Results showed that the high effective thermal conductivity of the foam accelerated heat removal in vortex regions, mitigating hot spots on the PV surface. Compared to a baffled channel alone, adding metal foam increased thermal efficiency by 3.03–7.69 %, electrical efficiency by 0.60–2.31 %, and total efficiency by 3.63–8.45 %. However, thicker foam raised flow resistance – boosting velocity and pressure loss - which diminished net efficiency gains at greater thicknesses.