Embodied and operational energy and carbon emissions of passive building in HSCW zone in China: A case study

Abstract

Passive building is generally regarded as the energy-efficient building to reduce the primary energy consumption and related carbon emissions. It is suggested that the most effective way to minimize the space heating energy demand is to decrease heat loss by enhancing the thermal and airtightness performance of building envelope.And it is suited to the buildings in cold climates for decreasing space heating energy consumption which dominates the operational energy. However, the appropriate design strategy of building depends on climates. In HSCW (hot summer and cold winter) zone in China, for instance, the space heating is just one issue of energy demand in operational stage, the energy use for cooling and dehumidification in summer also accounts for a considerable proportion in operational stage of buildings. The effect of decreasing the cooling energy demand will become smaller as thickness of insulation layer increases, the unfavorable highly insulated envelope may even cause the overheating risk in summer. In addition, embodied energy and carbon emissions will markedly increase as more materials are consumed in passive buildings. Therefore, in order to get an appropriate design strategy of passive buildings in HSCW zone in China, further research on energy consumption and carbon emissions of embodied and operational stage is needed. In this case, detailed life cycle analysis of embodied and operational energy use and carbon emissions of a passive building is given and then compared with a conventional building in the same unique climate zone. The embodied energy consumption and carbon emissions of the passive building is 7.31 GJ/m2 and carbon 0.98 t CO2 eq/m2, 37.6% and 16.2% higher than that of conventional building respectively. Due to the benefits on the operational stage, the total life cycle energy requirement and carbon emissions of passive building is 17.4% and 22.7% lower than that of conventional building, respectively. Towards a zero energy and impact building, the design of passive cooling, high efficiency cooling equipment and renewable energy to reduce remaining energy demand should be paid more attention in further passive buildings in this climate.