Thermal insulation performance of buildings with phase-change energy-storage wall structures

Considering that improving the energy efficiency of buildings is crucial to achieving China's carbon neutrality goal, the application of phase-change energy-storage (PCES) technology could be considered a practical and feasible approach. Currently, the heat transfer characteristics of PCES walls and their influence mechanisms on the indoor building environment are the key issues to be solved in this field. Based on gypsum-based phase-change materials (PCMs), outdoor, indoor and central PCES walls are designed in this study. Unsteady heat transfer experiments, finite element numerical simulations and energy consumption analyses were used to study the thermal behaviour of PCES walls, and the thermal insulation performance of the buildings utilizing these wall structures were assessed. The results show that the maximum temperature of inner surface of wall with PCMs applying at the interior side is reduced by 0.6 °C, and the maximum temperature lag is reduced by 0.8 h. The results also prove that buildings employing this PCES walls as envelope have a reduction of annual cooling energy consumption about 7.6%, and a reduction of annual carbon dioxide emissions by about 2%, comparing with conventional buildings. Thus, these results suggest that the use of PCES walls can effectively enhance the thermal insulation performance of buildings in summer. This research could provide an innovative idea for the design of PCES walls, which is of significance for the application of PCES walls in severe cold regions. •The unsteady heat transfer characteristics of three different PCES walls were tested•The thermal insulation performances of PCES walls were analysed.•The energy consumption and carbon dioxide emission of buildings with PCES walls were calculated.