A method to rank heat sinks in practice: the heat sink performance tester

Abstract

One way of cooling electronic devices is through enlarging the surface that is in contact with a fluid (usually air) by attaching a heat sink. 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, this 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. CFD modeling is no option unless time, a supercomputer and a calibration laboratory are available. This paper discusses a method to rank heat sinks given a certain application. The measurement is based on the extraction of the average heat transfer coefficient from time-dependent temperature curves as a function of velocity and bypass. Scaling the measured effective heat transfer coefficient by mass, volume, weight or height provides several performance metrics allowing designers a novel way of ranking heat sinks in conditions that resemble the application.