The Optimal Location Of Phase Change Material Layer In The Building Wall Under Annual Weather Condition

Improving the thermal insulation performance of building palisade structure is an important channel to achieve building energy efficiency. The PCM wallboard uses the latent heat of phase change materials to improve the palisade structure heat capacity and thermal inertia, and plays the role of regulation to reduce air conditioning and heating load.This paper establishes the dynamic heat transport mathematical model of the PCM wallboard. Firstly, the active construction in Nanjing area is taken as the simulation object, the decay rate of peak and valley heat flux as evaluation criteria, comparative analysis of the optimal location of phase change material layer in the building wall. There are 17 positions of PCM in the wall, the position 0 is closest to the inner surface of the room the position 17 is closest to the outer surface of the room. The results show:the optimal location of phase change material layer in the building wall is position 0/16L under annual weather condition when the phase transition temperature range is 26℃to28℃. At the same time, the paper researches the optimal position of the phase change material layer in the wall in different phase transition temperature range, the results prove:when the phase transition temperature range is 24℃to26℃, the decay rate of peak and valley heat flux of the inner surface of wall is the highest.Meanwhile, the passive buildings in Nanjing area is taken as the simulation object, this paper reserches uncomfortable level of the room, it draws the following conclusions:when the phase change material layer is placed in the eastern wall, the year-round comfort level is the best, the optimal location is position 0/16L. At the same time, this paper researches the optimal position of the phase change material layer in different phase transition temperature range, results showed that:when the phase transition temperature range is 27℃to29℃, it’s more effective to lower the uncomfortable level.Lastly, this paper takes Guangzhou, Beijing and Harbin as examples, simulates the optimal position of phase change material layer in the different climate zone. The results show that under annual weather condition, in Guangzhou, the phase transition temperature range is 26℃to28℃, when the location is position 3/16L, the decay rate of peak and valley heat flux is highest.In Beijing, the phase transition temperature range is 24℃to26℃, when the location is position 0/16L, the decay rate of peak and valley heat flux is highest. In Harbin, the phase transition temperature range is 22℃to24℃, when the location is position 0/16L, the decay rate of peak and valley heat flux is highest.