A Recent update of phase change materials (PCM’s) in cooling application

Abstract

The use of indirect evaporative cooling in dry weather conditions to charge phase change materials (PCMs) storage systems can reduce overall energy consumption. Lower thermal conductivity is the main limitation of PCM, so a suitable technique must be used to enhance thermal conductivity.. Studies showed that the selection of PCMs for free cooling applications is critical because it depends on the outside temperature at the charging period. Therefore, the outside temperature should be lower than the solidification temperature of the PCMs during charging, and the melting temperature should be lower than the inside temperature during the discharging process. The objective of this review article is to evaluate current phase change materials applications in cooling systems. The investigations about the application of PCMs in cooling systems undertaken by different researchers will be described in this article. Free cooling and heating system using building envelop, free cooling and heating using Air Handling Unit latent heat thermal storage systems, air conditioning, and refrigeration systems are discussed briefly. About 35% of these studies used PCMs used in roofs, ceilings, and attics. Moreover, 6% of studies used PCMs on the floor, so there is a need for future studies about the application of PCMs on the floor to storage energy at off-peak load hours and release it at peak load hours to reduce energy consumption costs. The results in the literature showed that using PV-PCM in the attic can reduce up to 55% of the attic cooling load. PCMs can store a large amount of coldness during the phase change process which takes place at a constant temperature, so it is appropriate to use in the building.