Whole biomass material envelope system for nearly-zero energy houses: Carbon footprint and construction cost assessment

Building envelopes have the potential to achieve energy savings of between 28% and 66%, and a reliable building envelope system can effectively reduce energy consumption and carbon emissions. This study proposed a whole biomass material envelope system (WBMES) for nearly -zero energy (NZE) houses. The construction materials of the WBMES are primarily biomass materials such as straw bale, wood, and bamboo. An NZE house was selected as a case study. According to the calculation results, the carbon footprint of the case was 326.54 kgCO2/m2, 14.24 kgCO2/m2, and 35.55 kgCO2/m2 center dot a in the material production, transportation, and operational stages, respectively. Compared with other cases found in other studies (including NZE and nonNZE buildings), the case house ranked well in reducing carbon emissions in the material production stage. However, it could only maintain the carbon emissions of the operational stages at an average level. According to the detailed simulation results from EnergyPlus, the airtightness and roof were the weakest parts of the heat balance and required strengthening. Meanwhile, the case study house had a low cost of $535.7/m2, similar to that of a typical building. Hence, the WBMES has good carbon reduction potential and low construction costs. It is suitable for construction in agricultural or undeveloped districts to reduce carbon emissions while maintaining construction costs at a low level.