Experimental investigation on natural convection heat loss characteristics of photovoltaic panel

In this study, natural convection heat loss of PV panel with non-uniform heat flux was investigated experimentally. The flat plate having the similar physical characteristics is adopted to simulate PV panel. Electrical heating is employed to simulate the solar power. Main concerns are directed to the effects of tilt angles θ, k (gradient of the heat flux) and heat flux q_w on the heat transfer from the flat plate. Regarding of this, the flat plates having different tilt angles and thermal boundary conditions were tested. The results reveal that the surface temperature of plate with non-uniform heat flux always rises with the heat flux rising, while the effects of tilt angle are very small. Compared with the uniform heat flux, the average natural convection heat transfer of the nonuniform heat flux is stronger when the tilt angle exceeds about 40°. Besides, with the heat flux increasing, the convective heat transfer also grows. However, the average natural convection heat loss for non-uniform heat flux decreases firstly and then increases with the tilt angle increasing, and it reaches the lowest value at about 45°.