Experimental and Numerical Analysis of an Innovative High Power LEDs Thermal Management System, based on Heat Sink- Heat Pipe Design

Abstract

The efficiency and lifespan of light emitting diodes (LEDs) are adversely affected by the junction temperature. Therefore, it is very important to operate a LED at a low junction temperature. In this study, it is aimed to minimize the junction temperature of high power LEDs so that reliability and light output of the device can be maximized. In the study, a heat pipe-heat sink cooler was designed for the high power LEDs. The study was carried out experimentally and the results obtained from the experimental study were also verified numerically in the ANSYS Fluent software. Total power inputs ranging between 40 W and 100 W were applied to the LEDs and the performance of the cooler in the current design was examined. To observe the effect of the heat pipe on the LED junction temperature, a heat sink without heat pipe was designed and analyzed both experimentally and numerically. The results show that, the heat sink with fin is sufficient at low LED input powers, while at high LED input powers, the heat pipe-heat sink provides much more effective cooling. At the same time, the effect of different thermal interface materials on LED junction temperature was observed, by using with materials with thermal conductivities of 1.8 W/m.K, 8.5 W/m.K and 11 W/m.K, for each power input. As the coefficient of thermal conductivity of the thermal interface materials increased, the temperature of the LED solder point decreased.

Keywords

• high power leds
• heat pipe
• thermal management
• ansys fluent