Innovative wall package made of macro-encapsulated phase change material and geopolymer concrete: in-field thermal analysis for a Mediterranean climate

The paper proposes the experimental characterization of a wall package made of geopolymer concrete and phase change materials (PCMs) in the climate of south Italy. Data collected from May to July 2021 were presented by elaborating surface temperatures and heat fluxes with the introduction of several new indices as the thermal stress reduction amplitude, the percentage of time in melting range and the extreme surface solicitations. The results indicate that the PCMs reduce the thermal solicitation and preserve the geopolymer blocks. The indoor surface temperature can be lowered also of 3°C during the hours with maximum sol-air temperatures and this could contribute to reduce the local discomfort phenomenon. Globally, the heat flux monitored on the geopolymer layer behind the PCM is attenuated and its trend is more regular; this reduction implies a reduction of heat gains through the opaque building envelope and finally a reduction of the energy demand.