Heat Transfer and Lifetime Estimation of High-Power Light Emitting Diodes (HPLED) Using Drop Shape Pin Fin Heat Sink Under Natural Convection

Abstract

High-Power Light Emitting Diodes (HPLEDs) are a leading example of modern lighting technology and are praised for being more efficient than traditional light source’s. This study explores the complex relationship between HPLED service life, junction temperature (T_j), and heat dissipation through drop-shaped pin fins type heat sink attached to HPLED. Four different power inputs 50, 100, 150, and 200W were analysed using three different vertical pin fin spacings (S_v = 25, 50, and 75 mm). A data acquisition system was created to measure temperature, current, LED light intensity (Lux), and voltage values using sensors. These values were then used as the best possible reference values for a well-known Arrhenius equation model to predict the lifetime of the device. The results shows, as power input levels rise, T_j also increases, which reduces the life of HPLEDs. There is a distinct inverse relationship between device lifetime and T_j that exhibits a nonlinear exponential decay pattern. For 200 and 50 W power input, respectively, the maximum junction temperature of the HPLED attaching drop-shaped pin fin heat sink was found to be 134.78°C and the minimum T_j was found to be 60.13°C. The drop-shaped fin pin heat sink with a 75 mm fin spacing was found to have a maximum heat transfer coefficient of 9.81 W/m²K. With a 200 W power dissipation and a junction temperature (T_j) of 134.78°C, the HPLED had a short expected operational life of 1780.2 hours. On the other hand, a projected lifetime of 3996.30 hours is anticipated at a higher temperature of T_j=112.18°C.