Addition of granular phase change materials (PCMs) and graphene to a cement-based mortar to improve its thermal performances

Abstract

The addition of phase change materials (PCMs) into building materials represents a valid strategy towards the improvement of their thermal performance and therefore of the indoor comfort. However, when paraffin PCMs are used, the thermal conductivity of the mixture inevitably decreases due to the PCM low thermal conductivity. The research here presented focused on the addition of granular paraffin PCM into a cement-based mortar to improve its thermal storage capacity, and of hydrophobic graphene to counterbalance the reduction in thermal conductivity. Experimental tests at laboratory scale and numerical simulations were carried out to compare the behavior of two equivalent radiant floor samples in terms of temperatures and heat fluxes. Lower temperature fluctuations and delayed minimum temperatures were observed in the mortar with PCM and graphene, if compared to the Reference one. Eventually, in order to investigate the possibility of using the new mortar in case of building refurbishment, a floor with the enhanced mortar lowered 1 cm was simulated and then compared to the reference one. Results showed that the surface of the lowered floor reached the same maximum temperature with the system on and up to 3 K higher with the system off.