Optimization of thermochromic materials parameters to improve energy efficiency in hot summer and cold winter regions

Solar radiant heat gain reduces air conditioning energy consumption and improves the thermal environment in winter, but the opposite is true in summer. Conventional building skin materials, with constant solar reflectance, fail to address the varying heat demands between seasons. This study investigates thermochromic materials (TCMs), which dynamically adjust their color and solar reflectance in response to environmental changes, thereby optimizing energy efficiency in hot-summer and cold-winter regions. Two key parameters of TCMs—discoloration temperature and reflectance range—are analyzed for their impact on energy savings. Results show that a coating with a discoloration temperature of 37.7 °C and a reflectance range of 60 %–90 % achieves the highest 10.76 % energy savings. Additionally, a life cycle economic evaluation reveals that TCMs are more cost-effective than other energy-saving materials, with an average annual cost as low as 0.53 RMB/m2-y.