Thermal performance and economy of PCM foamed cement walls for buildings in different climate zones

Using phase change material (PCM) into the building envelope is considered an effective thermal energy storage strategy to improve building thermal performance and reduce space heating/cooling loads. However, different phase transition temperatures and climatic conditions have a huge impact on application effect. This paper investigates the effects of walls containing PCM foamed cement on thermal performance and economy of single-story building in 5 different climate zones in China. The temperature, energy storage, energy consumption and the payback period for PCM foamed cement wall are analyzed by numerical simulation. The results indicate that the PCM foamed cement moderates the indoor and outdoor temperature differences in all 5 climate zones. Among which, Harbin (severe cold region) had the best increase in the south wall inner surface average temperature in January with an increase of 0.378 °C. The optimal phase transition temperature is close to the local annual average temperature except Harbin, and the energy saving rates are 20.17 % (Beijing), 15.87 % (Shenzhen), Shanghai(22.26 %), 37.02 % (Kunming). The shortest payback period is 5.95 years for the application of PCM foamed cement in Harbin, but in Kunming (mild region) at the current price, the investment cannot be recovered.