Optimum Insulation Thickness for Building Exterior Walls in 32 Regions of China to Save Energy and Reduce CO 2 Emissions

摘要

China accounts for approximately 30% of the CO 2 emissions—one of the largest proportions from a single nation. Therefore, reducing the CO 2 emissions in China will play a decisive role in global CO 2 emissions reduction. This paper is a proposal of optimum insulation thickness (OIT) for the exterior walls of buildings in 32 regions of China to save energy and reduce CO 2 emissions. The determination of the OIT for exterior walls its impact on the annual total energy cost and annual CO 2 emissions per unit area of building exterior walls were calculated for 32 regions of China using the life-cycle cost analysis (LCCA) and degree-days (DD) method. The results indicate that the annual total energy cost decreases up to the OIT level, and increases beyond the OIT level. The annual CO 2 emissions can be reduced by increasing the insulation thickness. It is predicted that the average total energy cost of 32 regions can potentially be decreased by about $5/m 2 -year (40%) and the average CO 2 emissions of the 32 regions can potentially be reduced by about 27 kg/m 2 -year (63%) when the OIT is applied. It also shows it is more effective to apply the OIT for the exterior walls of buildings to save annual total energy cost and reduce annual CO 2 emissions in the Severe Cold and Hot Summer & Cold Winter climatic zones rather than the other climatic zones of China.