Effect of Solar Irradiation on Thermal Performance of Heatsink—Numerical and Experimental Study

The reliability of electronics systems primarily depends on the temperature of the electronics components. The development of cost-effective thermal management solutions to cater to the cooling of next-generation electronics systems is the need of the hour. The extended surface is the most reliable, convenient, and cost-effective heat transfer technology to remove the heat generated by the electronics components. Power amplifiers are the critical devices used for outdoor communications which generate high heat flux during their operation. Since the communication systems are installed outdoors, the average solar irradiation falling on the system during sunny days is 600 W/m ² . A computational fluid dynamics (CFDs) model of a heatsink with a base area of 100 mm ×100 mm exposed to solar irradiation is developed to dissipate the heat generated by the power amplifier. The fin height is varied from 5 to 30 mm, fin thickness is varied from 2 to 3 mm and the spacing between the fins is varied from 4 to 6 mm. Surface properties such as emissivity and solar absorptivity of the fin surface are varied from 0.1 to 0.9 to study the effect of solar irradiation on the efficiency of the fin. For 30 mm fin height and emissivity 0.1, the heatsink base temperature increases from 57.8 °C to 66.1 °C and the fin efficiency reduces from 97.5% to 94.3% when the solar absorptivity of the fin surface is increased from 0.1 to 0.9. Similarly, for fin height 5 mm and emissivity 0.9, the heatsink base temperature increases from 63.9 °C to 77.7 °C and the computed fin efficiencies are 96.4% and 93.2% for solar absorptivity 0.1 and 0.9, respectively. Experiments are conducted to measure the base temperature of a heatsink to validate the CFD results. The contours of thermal resistance of heatsink for various configurations are plotted and an electronics cooling designer can choose an appropriate heatsink by knowing the geometric and surface properties of the heatsink.