Quantifying the performance advantage of using passive solar air heater with chimney for photovoltaic module cooling

The foreseeable growth of photovoltaic (PV) systems highlights the prominence of improving its efficiency. The performance of PV module deteriorates as a major part of irradiance is converted to heat. Amongst several PV thermal management techniques, passive air cooling is gaining importance due to its self-sustained nature. In the present experimental study, the performance of conventional solar air heater is enhanced by incorporating chimney. Further, by placing the PV module in the airflow path, its performance is improved compared to an identical module kept open to ambient. During testing, a maximum system efficiency of 35% was observed as air heater contributes to the maximum thermal efficiency of 25%. Further, due to better airflow over the PV module rear surface, a 13% reduction in surface temperature was observed compared to the outer module, which gave a 6% rise in power output. In such a combi system, the working of both PV and air heater complements the advantage to each other. Hence, the total efficiency of the air heater and PV module as two separate entities is always less than the system efficiency of the combi system.