Investigation of heat dissipation limits for high power LEDs

From the point of view of energy consumption, LED technology is the most efficient lighting method at present. Thermal and electrical aspects as well as mechanical issues should be considered when designing a LED lighting system. Thermal requirements are usually linked with the mechanical design, meaning that the lighting unit heat sink represents the enclosure assembly. In an attempt to obtain the optimal solution, along with the mathematical approach, simulations are needed in order to validate as well as refine the solution. The paper performs a thorough analysis concerning heat distribution in an 18W chip-on-board LED by performing both simulations and laboratory measurements. Using computational methods, a virtual LED model has been designed having the material properties as input data for a thermal solver. Furthermore, laboratory measurements were made on the LED in order to compare the results with the simulation. This thermal study offers valuable information about the limits of heat evacuation in lighting systems that use high power LEDs.