Thermal Design and Simulation of In-Cabinet Electronic Equipment

This paper describes thermal analysis techniques which can be applied to electronic equipment contained in any cabinet, especially those subject to natural environments. The method can effectively predict cabinet temperatures at various in-cabinet locations even when the cabinet contains fans and louvres to assist air circulation and ventilation. The technique involves a sophisticated analytical simulation using a proprietary computer software system (SCAMPER) but may also be approximated by a simple manual method using a scientific calculator. To demonstrate the application of these techniques, the paper discusses results obtained from a cabinet of telecommunications equipment consisting of: 1) electronic equipment, 2) sealed lead acid storage batteries, and 3) rectifiers to supply dc power. The results show the temperature computation at specific locations and the impact of the louvre positions. The battery temperature (internal and external) is also predicted which enables us to predict the expected battery life. In-cabinet environmental conditions, over a typical year, are also predicted.