Improved thermal design of fin heat sink for high-power LED lamp cooling

The efficient cooling is very important for a light emitting diode (LED) module because both the energy efficiency and lifespan decrease significantly as the junction temperature increases. The fin heat sink is commonly used for cooling LED modules with natural convection conditions. This work proposed a new design method for high-power LED lamp cooling by combining plate fins with pin fins and oblique fins. Two new types of fin heat sinks called the pin-plate fin heat sink (PPF) and the oblique-plate fin heat sink (OPF) were designed and their heat dissipation performances were compared with three conventional fin heat sinks, the plate fin heat sink, the pin fin heat sink and the oblique fin heat sink. The LED module was assumed to be operated under 1 atmospheric pressure and its heat input is set to 4 watts. The PPF and OPF models show lower junction temperatures by about 6°C ~ 12°C than those of three conventional models. The PPF with 8 plate fins inside (PPF-8) and the OPF with 7 plate fins inside (OPF-7) showed the best thermal performance among all the PPF and OPF designs, respectively. The total thermal resistances of the PPF-8 and OPF-7 models decreased by 9.0% ~ 15.6% compared to those of three conventional models.