Thermal Design and Optimization of LED Integrated with Thermoelectric Cooler in Natural Convection

In order to improve the thermal performance of LED lamp with high heat flux in natural convection, a thermoelectric cooler (TEC) was presented to meet the cooling requirement of a compact lamp with single high-power LED. The performance parameters of TEC were determined accurately by regression analysis for TEC experimental data at different work status. The equivalent thermal circuits of the compact LED modules with TEC and without TEC were established based on electrical-thermal analogy. Some mathematic models of equivalent thermal circuits were developed to quickly predict the accurate thermal performance of LED modules following the specified calculation procedure in this paper. The thermal performance analysis results show that the best cooling performance can be obtained at the optimum input TEC current for a specific LED power dissipation. The thermal performance of LED modules with TEC can be superior to that of modules without TEC and be better at low LED power dissipations than at high ones. Two-objective optimization was carried out using three design variables of fin to minimize the junction temperature and fin mass simultaneously. For the un-optimized and optimized modules, the comparison results of thermal performance demonstrate that the effective operating range of TEC in optimized module performs broader than that in un-optimized module. The LED power dissipation of optimized module can reach a higher performance than that of un-optimized one. At the LED power dissipation of 0.493 W, the minimum junction temperature is 15.66 ℃ and much lower than the ambient temperature of 30 ℃. For the LED modules with TEC, the equivalent thermal circuit models presented based on TEC experimental data can contribute to the thermal design, performance analysis and structural optimization. © 2018, Science Press. All right reserved.