Economic viability of phase-changing materials in residential buildings – A case study in Alice Springs, Australia

The use of phase-changing materials (PCM) in residential envelopes is an emerging technology that promises significant cooling and heating energy savings. Such energy savings are expected due to PCM's inherent energy storage capability, realized as physical transformation processes, during hot–cold weather transitions. However, this technology has limited market penetration due to a lack of demonstrated economic advantages for constructing and retrofitting buildings. This paper addresses the techno-economic viability of implementing PCM in an average residential dwelling in Alice Springs, Australia. The life-cycle cost analysis is performed by modeling the transient characteristics of the PCM envelope component through a proxy heat-pump with tuned Coefficient of Performance (COP) and seasonal efficiency to match the experimental annual heating–cooling characteristics. Three instances were considered, namely: (a) basic PCM implementation; (b) PCM implementation with capital expenditure (CAPEX) subsidies from a government program (Grant); and (c) use of a novel and less expensive (low-cost) encapsulated PCM technology to address the hurdle of the typically significant CAPEX associated with conventional PCM in the Australian market. Results demonstrated that PCM is a promising technology with potential energy savings in hot-arid climates. However, it requires subsidies of nearly 50% of the CAPEX or the implementation of the novel low-cost technology to become financially attractive. The present case study shows both alternatives' profitability, with the former resulting in a 1.2 benefit-cost (BC) ratio and equity payback (EP) of 9.3 years. The latter shows a BC ratio of 1.7 and an EP period of 8.3 years.