Characterization of novel shape‐stabilized phase change material mortar: Portland cement containing Na 2 SO 4 ·10H 2 O and fly ash for energy‐efficient building

In this work, a novel Na2SO4·10H2O/fly ash shape-stabilized phase change material mortar (PCM mortar) was prepared for building energy efficiency, in the context of energy conservation and environmental protection. The working, mechanical, and thermal properties of this proposed PCM mortar were investigated. The experiment results showed that the incorporation of PCMs greatly increased the thermal inertia of the mortar, while corresponding compressive strength was little affected. Specifically, when the blending amount of PCMs reached 15%, the thermal storage capacity of mortar sample (PCM-15) was 6.18 × 104 kJ/m3, which is 2.4 times of that for mortar sample without PCM (OPC) evaluated by theoretical calculations, while the corresponding compressive strength of mortar sample (PCM-15) still remained above 31 MPa. Furthermore, the effects of PCM mortar on thermal comfort and energy use of buildings were studied by using experiment and simulation methods, respectively. The control experiments showed that PCM mortar can effectively alleviate the influence of outdoor temperature on indoor temperature compared with OPC. Temperature difference between PCM-15 and OPC board can reach 4.6°C (inner surface) and 8.6°C (outer surface), respectively. Meanwhile, temperature difference of internal space reached 1.2°C. The simulation results showed that the energy consumption per unit building area was reduced by 4.4 and 18.7 kg/m2 in Guangzhou and Harbin, respectively, with PCM mortar as the envelope structure. Hence, the proposed PCM mortar showed significant thermal and mechanical properties and had broad application prospects in regulating indoor temperature and constructing energy-efficient buildings.