Renewable wood-phase change material composites for passive temperature regulation of buildings

The buildings sector consumes a significant amount of raw materials and energy resources, with high-energy consumption and environmental impact. To achieve net-zero emissions, it is crucial to address the substantial carbon footprint generated by buildings in operation. A promising solution lies in the development of renewable and sustainable building materials capable of efficiently storing thermal energy to regulate indoor temperature without relying on operational energy (HVAC systems). Here we report on a wood-phase change material (PCM) composite, referred to as PCM-wood, which holds potential for energy-efficient buildings. The composite shows excellent thermal regulation capability with a melting enthalpy of 113 J g−1 at 22 °C and solidification enthalpy of 114 J g−1 at 21 °C. Despite some loss of mass and in enthalpy of melting, the PCM-wood showcases stable thermal regulation performance over 50 heating/cooling cycles and the wood modification does not negatively impact the tensile strength of the wood material. Hence, the PCM-wood composite combines structural performance and efficient energy storage with the ability to passively regulate indoor temperature, buffering fluctuations of more than 6 °C. Such a passive thermal regulation strategy has the potential to significantly reduce energy consumption in the building sector and to help achieve net-zero buildings by reducing energy consumption and mitigating CO2 emissions.