An Experimental Study of the Effects of Heat-Sink Surface Form on PV Module Cooling and Electrical Performance

In this study, the effect of the fin surface on the electrical performance of passively cooled photovoltaics (PV) modules equipped with flat (${\mathrm{PV}}_{\mathrm{f}}$) and tread (${\mathrm{PV}}_{\mathrm{t}}$) surface finned heat sinks was experimentally investigated. ${\mathrm{PV}}_{\mathrm{f}}$ and ${\mathrm{PV}}_{\mathrm{t}}$ modules were fabricated with heat sinks by filling phase change material (paraffin)/aluminum chip mixture between the PV module and heat sink. The mean ambient temperature, solar radiation, and solar power during the experiment were about 13°C, $864\mathrm{W}/{\mathrm{m}}^2$, and 247, respectively. The electrical power of the ${\mathrm{PV}}_{\mathrm{f}}$ and ${\mathrm{PV}}_{\mathrm{t}}$ modules was increased by 10.84% and 17.2%, respectively, while the average temperature was decreased by 11.78% and 16.5%, respectively, compared to the PV module. The ${\mathrm{PV}}_{\mathrm{t}}$ module provided 5.37% more effective cooling and a 5.74% higher electrical power than the ${\mathrm{PV}}_{\mathrm{f}}$ module. The electrical efficiency of the PV module was 11.35%, and the rate of increase was 1.21% and 1.95% for the ${\mathrm{PV}}_{\mathrm{f}}$ and ${\mathrm{PV}}_{\mathrm{t}}$ modules via cooling. Compared to the PV module, the electrical exergy of the ${\mathrm{PV}}_{\mathrm{f}}$ and ${\mathrm{PV}}_{\mathrm{t}}$ modules increased by 10.84% and 17.2%, respectively, at an average solar exergy of 230.61 W, while their thermal exergy decreased by 23.64% and 32.3%, respectively. Compared to the ${\mathrm{PV}}_{\mathrm{f}}$ module, the thermal exergy of the ${\mathrm{PV}}_{\mathrm{t}}$ module was reduced by 11.34%, and the electrical exergy was increased by 5.74%. The increase in exergy efficiency is 3.14% and 4.51% for ${\mathrm{PV}}_{\mathrm{f}}$ and ${\mathrm{PV}}_{\mathrm{t}}$ modules versus the PV module.

A small part of solar energy is converted into electricity, while a significant part is converted into heat and increases the temperature of the PV cells. An increase in the temperature of PV cells harms conversion efficiency and causes an increase in the share of converted heat and a decrease in electricity generation. The conversion efficiency can be improved by removing the accumulated heat of the module. In practice, there are various examples of passive and active cooling. Active cooling methods enhance heat transfer by forcing the fluid flow with a fan or pump to facilitate heat removal. Active cooling applications are heavy, expensive, and complicated. Natural heat convection can be maximized with heat spreaders or heat sinks during passive cooling. Passive cooling may not dissipate heat as effectively as active cooling. Passive cooling systems are cheap, lightweight, and uncomplicated, and they can become even more valuable as their thermal efficiency increases. This study addresses the effect of the heat sink fin surface on the cooling and electrical performance of flat and tread finned heat sinks coupled PV modules that are paraffin/aluminum chips blend backplane filled. 1st and 2nd law PV module efficiencies improved by about 1.21% and 1.95% and 3.14% and 4.51% with flat and tread finned heat sinks, respectively.