夏热冬冷地区绿色建筑外墙节能特性的LBM模拟及效益分析

To investigate the green buidling’s typical insulated external walls with common insulating materials in hot summer and cold winter areas, a multiple-relaxation-time lattice Boltzmann method (MRT-LBM) was developed for solving the conjugate heat transfer problem. The transient heat transfer process in the wall was analyzed under an intermittent energy consumption condition, and the energy saving characteristics of different insulated external walls were studied. Based on this, a computational approach for the incremental comprehensive benefit of the insulated wall was developed to analyze its incremental cost and incremental benefit. Under this circumstance, an evaluation model for the incremental comprehensive benefit was constructed to obtain the optimum design of insultated external walls. The results indicate that the walls with interior insulating layer have the best energy saving characteristic in this specific region. The whole lifetime incremental comprehensive benefit of the walls with exterior insulating layer or using expensive insulating materials is negative even though they could still save energy during the energy consumption period. Due to this reason, the walls with exterior insulating layer and expensive insulating materials should not be used in the real engineering applications. In addition, it is found that the energy saving amount of insulated external walls increases with the increment of the insulating layer thickness. However, the increased insulating layer could generate extra incremental cost. Hence, the optimum insulating layer thickness of external walls should be determined with fully considering their energy saving characteristic and incremental cost to achive a maximum incremental comprehensive benefit during the whole lifetime.