Numerical investigations on thermal performance of phase change material-assisted radial heat sink for High-Power Chip-on-Board LEDs

• PCM based thermal management technique for high power COB LEDs . • Comprehensive study with heat sink materials, PCMs, power ratings and fin designs. • Wavy fins outperform conventional straight fins, reducing temperature by 4.07%. • PFA-4 exhibits superior performance, delays temperature spike by 1725 s. • 100 W COB LED temperature maintained at optimum level for 1800 s with PCM cooling. High power Chip-on-board (COB) Light emitting diodes (LEDs) are more prevalent in vehicles and other lighting applications. Thermal management of LEDs is essential to dissipate the heat generated during their working for improved efficiency and life. Air cooling is the widely adopted methodology for LED cooling, which fails to perform satisfactorily for LEDs of higher power rating. In this study, a validated mathematical model of cooling system equipped with metallic fins and phase change material (PCM) is developed and thermal response of nine different configurations of the system are simulated to establish the feasibility of PCM adoption for the cooling of high-power COB-LEDs. Temporal variation of maximum temperature and PCM’s liquid fraction are monitored for all the configurations and used as the comparison parameters for finding the best configuration for COB-LED. It is found that PCM based heat sink with wavy fins shows better thermal performance compared to conventional straight finned heat sink for considerable duration of LED operation. A temperature drop of 4.08 % is obtained when wavy fins are used instead of conventional straight fins for same LED under same thermal environment. Heat sink configuration with wavy fins and PCM (PFA-4) is found as the best configuration, which can delay the temperature spike of COB LED by 1700 s compared to others. The effect of thermophysical properties of the heat sink and PCM materials on thermal performance of proposed system is also studied, with copper heat sink and erythritol configuration showing the best performance among the configurations considered.