Thermo and light-responsive building envelope: Energy analysis under different climate conditions

Building envelope plays a predominant role in attaining building energy efficiency and thermal comfort. This study proposes a new paradigm for enhancing energy efficiency in buildings by designing adaptive building envelope that embraces dynamic response to the fluctuating climatic condition. Adaptive envelope is designed by integrating building roof with thermochromic (TC) coating (namely TC roof) and placing phase change material (PCM) in the wall (namely PCM wall), which could intelligently manage both solar energy and thermal energy in the buildings. EnergyPlus simulation is implemented to unveil the potential energy savings of using adaptive envelope for the building under five distinctive climatic conditions. The simulation results show that in comparison to traditional envelope, the use of TC roof saves total energy consumption up to 13% and reduces CO2 emission by 4%; TC roof-PCM wall gives rise to total energy saving of up to 19% and reduction in CO2 emission by up to 5%, especially for the building in warm region. The sensitivity analysis reveals that the PCM layer outside the wall insulation causes more energy demand by up to 7%; the increasing thickness of PCM layer only brings positive impact on the performance of the building in severe cold and hot climate zones; the increase in thickness of TC roof increases total energy saving of up to 29% and reduction in CO2 emission by up to 8%. The methodology presented in this study guides the design of adaptive envelope for energy efficient buildings in different climate zones.