Improvement of the photovoltaic panel cooling by natural air ventilation

The operating temperature increase in solar photovoltaic modules is a major problem, which affects their performance negatively. This numerical study introduces the effect of natural convection air-cooling on the performance a novel hybrid photovoltaic/thermal collector. The standard k-epsilon turbulence model is implemented for describing the turbulent natural convection. For improving the heat transfer rate of a novel photovoltaic/thermal collector system (PV/T), a sloped entrance channel (SEC) and an aluminum flat plate (AFP) were installed. The effects of SEC geometry parameters, the number of AFP and their distance to the photovoltaic module (PV) on the average Nusselt number are investigated. In addition, the effect of the PV/T system tilt angle and Rayleigh number on the thermo-hydrodynamic flow behavior has been discussed. The results indicated that the heat transfer rate of the new hybrid PV/T system was improved by up to 20%, compared to the reference case without an aluminum flat plate. In addition, increasing the tilt angle of the PV/T system boosts airflow velocity, particularly for high Rayleigh number values (with and without AFP). Furthermore, several correlations, as functions of Rayleigh numbers and inlet channel dimensions, have been developed to predict the average Nusselt number.