Copper wick based loop heat pipe for thermal management of a high-power LED module

Abstract

Contemporary high-power LED modules are subjected to severe thermal management challenges due to continuing miniaturization and increased heat flux levels. The thermal loads need to be effectively dissipated to improve module reliability by maintaining the junction temperature below 120 °C. The viability of a Loop Heat Pipe (LHP), with copper as the wick material, as a potential thermal management solution for a 200 W high-power LED module is demonstrated in this work. The investigation is conducted in two stages. Firstly, the thermal performance of the LHP is characterized by using different working fluids, and sink temperatures, to obtain the optimum working conditions, using a heater assembly mimicking the LED module. Subsequently, the LHP is integrated with an actual high-power LED module, and this thermo-mechanical demonstrator is then characterized under different real-time operating conditions. Complimentary 3D computational heat transfer simulations are carried out to estimate the LED junction temperature and visualize the thermal fields generated in the LED module. The results demonstrate the efficacy of the copper-methanol LHP design for successful thermal management of the high-power LED module dissipating over 100 W/cm2 (maintaining junction temperature below 120 °C for the 200 W nominal power LED module).