Study On The Effect Of Coupled Heat And Moisture Transfer Of The Whole Building On Indoor Thermal And Moisture Environment And Energy Consumption In Hot Summer And Cold Winter Area

Most building materials are porous,and composed of solid matrix and pores.Under high temperature and high humidity conditions,moisture movement is possible only in the vapor and liquid states.the moisture transfer and heat transfer process influence each other.The coupled heat and moisture transfer process in the wall not only has a significant impact on the indoor hygrothermal environment,but also on the building energy consumption.The theoretical research on the coupled heat and moisture transfer of the whole building is of great significance to improve the indoor hygrothermal environment and save energy consumption.Taking four typical cities Chengdu,Shanghai,Changsha and Shaoguan in hot summer and cold winter area as examples,the effect of coupled heat and moisture transfer of whole building on indoor hygrothermal environment and energy consumption were studied in this paper.The details are as follows:(1)In order to compare the accuracy of the whole building model with and without considering the moisture transfer in the hot summer and cold winter area,an experimental platform was built in Nanchang under the natural conditions.The indoor temperature and relative humidity,the temperature and relative humidity at the midpoint of the wall,the temperature of inner and outer surfaces of roof were taken as the analysis objects,and their measured values were compared with the simulated values of the two models.The results show that in the hot summer and cold winter area,the simulation value of the hygrothermal model is closer to the measured value,especially in simulating indoor relative humidity.(2)Under the natural climatic conditions,the office buildings in Chengdu,Shanghai,Changsha and Shaoguan were simulated.The indoor temperature and relative humidity,heat and moisture fluxes that cross the zone boundaries calculated by two models were compared when the different interior materials(gypsum plaster,gypsum-fibreboard and cement board)and different insulation materials(XPS,EPS and rock wool)were used.The results show that the difference of indoor temperature calculated by the two models is small,and the fluctuation of indoor relative humidity of hygrothermal model is obviously slower.When the coupled heat and moisture transfer is neglected,the annual average indoor temperature is underestimated by about 0.1?,and the average relative humidity is underestimated by about 2%.The heat fluxes of different walls are increased by 1.97%?2.68%higher than that calculated by hygrothermal model.When the coupled heat and moisture transfer is considered,the peak value of heat flow wave between walls and indoor is lower,and the trough value is higher.The capability of humidity adsorption-desorption of different inner materials is:cement board>gypsum-fibreboard>gypsum plaster.The moisture fluxes of inner surface of different insulation walls are lower than that of the ordinary wall and there is little difference in the moisture fluxes of different insulation walls.(3)When the indoor temperature was controlled and the relative humidity was not controlled,the risk of condensation on the inner surface of different material walls was evaluated by using the hygrothermal model of whole building.The results show that the inner surface temperature of walls with different materials are higher than the indoor dew point temperature by more than 1.21?.So there is no condensation.(4)WUFI-Plus was used to simulate the annual energy consumption of different exterior insulation materials and different interior materials walls with two models respectively.The energy consumption of cooling,heating,latent heat and the annual energy consumption were analyzed respectively.The simulation results show that in four typical cities in hot summer and cold winter regions,the heating energy consumption of different insulation walls are decreased by 2.28%?5.31%,the cooling energy consumption are increased by 7.24%?11.49%,the heating energy consumption of walls with different inner materials are reduced by 1.53%?4.57%,and the cooling energy consumption are increased by 7.97%?14.07%.When the moisture transfer is neglected,the latent energy of different insulation walls and different inner materials walls are underestimated by 8.5%?16.69%and 8.94%?19.43%,respectively.The annual energy consumption of different insulation walls and different inner materials walls are underestimated by 2.76%?6.28%and 2.32%?6.91%respectively.The order of annual latent energy and total energy consumption of walls with different inner materials is cement board>gypsum-fibreboard>gypsum plaster.Among XPS,EPS and rock wool,XPS insulation wall has the best energy saving effect.Among the four cities of Chengdu,Shanghai,Changsha and Shaoguan,the deviation of latent energy between the two models is the largest in Shaoguan and the smallest in Shanghai.