Computational fluid dynamics analysis and experimental validation of improvement in overall energy efficiency of a solar photovoltaic panel by thermal energy recovery

The electrical efficiency of solar photovoltaic (PV) panel decreases with increase in its temperature because of its negative temperature co-efficient. This problem has been identified and attempts have been made to cool the photovoltaic panel by transferring heat by researchers the world over. The capitalization of the transferred heat for useful purpose is of prime importance since the conventional solar PV panel has the conversion efficiency of only 5%-17%. This means, about 83%-95% of incident energy is wasted and the proposition of recovering energy from solar PV panel can tap more thermal energy than electrical energy generated by PV panel itself. The present paper addresses this objective. The heat was transferred by direct contact heat exchange with flowing water from top of the panel. The direct contact heat exchange from top surface was found efficient in recovering energy as well improving the performance of PV panel. The refraction of light as it passes through the water layer straightens the incident radiation. The straightened radiation along with lower temperature of PV panel synergistically increases photovoltaic conversion efficiency. The computational fluid dynamics simulation of PV panel temperature closely resembles experimental data. There is a potential to recover energy at larger scale for large scale solar PV installations. Thus, the present paper proposes the win-win scenario of improved panel performance and maximum energy recovery. (C) 2014 AIP Publishing LLC.