Passive cooling of small telecommunication enclosures. Case study and practical approach

The dynamic progress in development of telecommunication equipment along with harsh environment of its applications, are driving increasing demand for optimal thermal management of the outdoor enclosures. There are number of methods currently utilized to remove waste heat from the enclosure. They represent active means such as air conditioning or thermoelectric cooling, semi-active such as air-to-air heat exchanger or passive such as convection cooling. Due to reliability and service issues, the trend is toward a fully passive method with minimum moving parts. The use of the phase change material (PCM) method represents such an approach. The PCM method uses the phenomena of waste heat absorption via thermal capacity of the phase change process. The paper discusses the application of PCM for cooling of an enclosure with variety of electronic equipment (battery vault, distributed power equipment, telecommunication, etc.). The challenges associated with the heat removal in such applications are presented followed by the PCM technique application proposal and system design methodology. The simulation, laboratory and field test data are presented for the specific application (including battery vault and small enclosures with telecommunication equipment). Finally, the comments on applicability of Bellcore specifications followed by application range and method limitations are discussed.