Heat Sink Basics from an Industrial Point of View

Abstract

Several other chapters (especially, Chap. 1 and 2) focus on the complexity of the physics that determines the performance of light-emitting diode (LED)-based systems. It is evident that temperature plays a significant role in optimizing light output and reliability. In many cases, the area available for cooling for a medium to high power LED is insufficient and hence area extension is required, usually by means of a local heat sink (using heat pipes to transfer the heat to where sufficient area is available is another option). Hence, an important way of controlling the temperature is by a proper choice of a heat sink. While in many applications the design freedom is limited, such as in retrofit LED lamps, the designer is still confronted with many questions: shape, number of fins, fin thickness, gap between fins, base dimensions, material, etc. Since literally thousands of heat sinks are available, many designers are confronted with the question: which one? Very often, the designer’s choice is based on cost and manufacturer’s data. Unfortunately, these data cannot be used with confidence because they are almost exclusively based on measurements in a closed duct, thereby disregarding bypass effects and inflow conditions.