The use of phase change chemicals for reserve cooling and energy conserving cooling systems in telecommunication equipment buildings

The authors outline Telecom Australia's development work and achievements in the use of the relatively high latent heat of fusion and thermal storage of phase change chemicals (PCC). Novel PCC applications, which have been successfully implemented into the Australian telecommunications network, relate to the use of PCC encapsulated in 1 m long plastic tubes to provide room temperature control after failure of the normal cooling plant. Experience has shown that the use of PCC in suitable installations can provide a simple, low-cost, maintenance-free solution to protect temperature-sensitive electronic equipment from excessive temperature rise during times of loss of normal cooling. The authors introduce a novel type of energy-conserving cooling system currently under testing and evaluation. This system combines the use of a variable-volume fresh-air cycle for normal operation on cool days, with refrigeration-type cooling on hot days, coupled with a PCC thermal storage to provide reserve cooling, for enhanced reliability