Many phase change materials (PCMs) are available with building envelope use potential. PCM in a building envelope stores heat under warm climate as it changes from solid to liquid phase at the melting temperature. Mainly, the latent heat of fusion is stored, which reduces the daily heat flux from the outdoors into the building. Thus, the indoor cooling requirement is reduced. When the outdoor temperature falls, PCM releases the stored heat into the atmosphere over the phase change from liquid to solid that may offset the internal heating needs depending on the design of the PCM application. The PCMs exhibit a great variety in their properties. While many researchers are optimizing the use of PCM for a building application under specific climates, most of them focus on the energy-saving potential of PCMs. Other criteria, such as economic feasibility, environmental hazards, stability, fire resistance, and non-thermal physical properties, should also be considered. Therefore, with many criteria to consider, a sound selection method is necessary for choosing a suitable alternative PCM in an application. Some phase change materials were examined and ranked by taking into consideration their thermal and non-thermal properties. These properties were assessed using a multi-criteria decision-making tool called the Analytic Hierarchy Process (AHP). The results of this paper illustrate a pathway for selecting suitable PCMs and provide support to PCM application in building envelopes.
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