An innovative lightweight aggregate composite phase change material for thermal energy storage enhancement of concrete under hot weather conditions

The incorporation of form-stabilized phase change materials (FS-PCMs) in construction materials is known to hold substantial promises for enhancing the energy efficiency of buildings and decreasing the power consumption, especially under hot weather conditions. However, the cost of PCMs, complexity of their preparation process, leakage problems, and low thermal conductivity, limit their use in civil infrastructure. In this study, a low-cost and lightweight aggregate, namely scoria (SC) was used as a supporting material along with PEG to develop a SC/PEG composite (SCP) PCM. Cement paste coating was applied on the developed PCM to prevent leakage of PEG and improve the thermal conductivity of the composite PCM. It was noted that the developed SCP is chemically stable for 47 % PEG and it exhibited outstanding thermal stability after 200 cycles of melting and solidification without signs of leakage. Further, the developed SCPC has an energy storage capacity and melting enthalpy of 96.7 % and 35.8 J/g, respectively. Moreover, varying quantity of SCPC was replaced with SC to prepare thermal energy storage concrete (MSCPC). It was noted that up to 80 % MSCPC can be used to produce structural grade concrete. Besides, the maximum temperature reduction and time shifting were 5.49 °C and 77.8 %, respectively. Thus, the prepared MSCPC not only serves the purpose of lowering the energy consumption, but also exhibits exceptional energy storage and release capabilities. These positive attributes collectively suggest that the engineered MSCPC can be effectively employed to enhance the thermal efficiency in buildings.