Life-Cycle Assessment of phase-change materials in buildings: A review

Contemporary construction industry is one of the major energy consumers and polluters. Therefore, recent pledges for decarbonization and mitigation of human-related environmental impacts necessitate transition of the industry to more efficient energy sources such as solar radiation and other renewables. These efforts are hampered by unstable energy supply of the renewables, which creates the need for energy storage systems. One of the proposed solutions is utilization of phase-change materials for latent heat storage. This field of research is intensively studied and many applications of PCMs were already introduced. However, the research focuses on energy and cost efficiency of the PCMs and their environmental impacts are seldom analysed. This paper therefore reviews available literature and maps the state-of-art in the in this field, identifies contemporary challenges and viable future research prospects. The review shows notable lack of accurate data describing environmental impacts of the PCMs. Most reviewed works utilize generic datasets, which reduces their accuracy. Still, it could be said that application of contemporary PCMs with relatively high energy storage density could be advantageous in technical systems such as space heating or cooling. Environmental and economic payback time of such applications could be less than two years. In contrast, applications in building structures are not desirable due to notable increase of embodied environmental impacts related with addition of a PCM and (if necessary) its container. This is true especially for organic PCMs based on fossil fuels, such as paraffins.