Temperature limiting systems for environmental reliability of telecommunication equipment enclosures

Recently, Telecom Australia has pioneered practical cost-effective methods for using the relatively high latent heat of fusion of phase-change chemicals (PCC) to provide thermal storage reserve cooling and conservation of energy in the building environment. The authors identify and outline performance characteristics of currently used PCC systems. They also introduce a novel passive building-cooling system for special high-reliability applications in remote-area communication sites. Such a low-cost minimum-maintenance system combines a thermally transparent equipment room that will maintain equipment within satisfactory environmental limits for most of the year with a special PCC thermal storage unit to give additional reserve cooling on hot days. The cool PCC storage may be provided through either a small air-conditioner or a fresh-air cycle during times of cooler weather. Mention is made of PCCs that are currently available in Australia and their suitability for application in PCC systems. PCC systems that are successfully being used by Telecom as well as exploratory PCC systems that are being investigated are briefly reviewed