A practical ranking system for evaluation of industry viable phase change materials for use in concrete

The increasing demand for environmental sustainability has prompted a growth in the production and implementation of energy efficient building materials. The use of phase change materials (PCMs) in buildings has proven to be an effective way of improving thermal regulation in buildings. However, the effectiveness of various PCMs has not yet been quantitatively assessed to identify which are superior. This paper conducted a critical review on PCMs and incorporation methods, and developed a novel ranking system based on the literature to assess and identify superior PCMs with respect to their thermal performance and economic efficiency. Initially, 24 potential PCMs were selected based on appropriate melting temperature and adequate heat of fusion values for building applications. Having taken the technical and environmental considerations into account, 20 PCMs (four were removed from the initial selection) were evaluated using the developed ranking system for their use in concrete. The salt hydrate eutectic of calcium chloride hexahydrate and magnesium chloride hexahydrate was found to perform the best based on the ranking results. To examine the viability of PCM-concrete as a thermally efficient building material, an economic and environmental case study evaluation has also been undertaken on its use in a typical New South Wales home. It was found that the payback period on the capital investment of the material was much less than the lifetime of the building, indicating that the technology is financially viable. Over a fifty year lifespan, the home would reduce a minimum of 28 tonnes of carbon dioxide emissions. Therefore, this technology could help Australia reach its 2030 greenhouse gas emissions reduction target.