Research On Heat And Moisture Transfer Process And Its Influence On Indoor Environment Of Building Structure With Near Zero Energy Consumption In The Cold And Severe Cold Area

As a newer building energy-saving comprehensive technology,near-zero energy building has become an important research object in the development of China's construction industry.In the ultra-low energy technology system of passive houses,the thermal insulation performance of the maintenance structure becomes the key point of energy-saving effect of near-zero energy buildings,and it also becomes an important part that affects indoor thermal comfort.The building envelope structure is a multi-layered porous structure that performs heat transfer and wet transfer under the influence of indoor and outdoor temperature difference and water vapor partial pressure difference.This is a typical heat-moisture coupled migration process.When the material's holes are filled with moist air,liquid water or ice,it will directly affect the thermal properties of the material.The formation of latent heat through the wall into the room by wet air also affects the internal environment and energy consumption of the building.However,the wet transfer process is not considered in current conventional thermal calculations and energy analysis.This paper takes near-zero energy buildings as the research object.Firstly,it analyzes the development and classification of near-zero energy buildings,technical indicators and architectural design.Secondly,through the field research of near-zero energy buildings in Shenyang Jianzhu University,the corresponding building data is consulted.The research is located in Shenyang's near-zero energy demonstration building.Aiming at the thermal insulation wall of near-zero energy buildings under the combined heat and moisture interaction,three kinds of building materials such as EPS,rock wool and polyurethane in Harbin,Changchun,Shenyang,Tianjin and Beijing in five cold and cold regions were selected for simulation analysis.Using the thermal and humid energy simulation software WUFI-PLUS,considering the CTF algorithm and dynamic heat transfer coefficient of the heat transfer of the envelope structure,the HAM algorithm for the thermal-humid coupling transfer of the enclosure structure is considered,respectively,for the typical cities of severe cold and cold regions,Beijing,Analyze the indoor comfort and building energy consumption of near zero-energy buildings in Tianjin,Shenyang,Changchun and Harbin,calculate building energy consumption and indoor thermal environment(including indoor temperature and humidity and its fluctuations,wall surface radiation intensity,etc.)Analyze the potential overheating problem in high-efficiency heat preservation and high-density population environment,and analyze the influence of dynamic heat transfer of different thermal insulation systems on building energy consumption,indoor heat and humidity environment and indoor thermal comfort.It is found that the heat-humidity coupling effect of building envelope structure has obvious influence on annual cooling,heating energy consumption,total building energy consumption and indoor relative humidity.It should be considered in air conditioning equipment,air conditioning system selection and environmental prediction analysis.These problems may cause economical waste and comfort problems such as reduced energy efficiency of the air conditioning system or failure to meet control requirements.Sensitivity factors affecting indoor wet environments using the HAM model:air conditioning operating mode and number of ventilation changes,and whether or not to consider the wet transfer of the enclosure.It has been found that the use of air conditioning equipment with a humidity control mode can effectively reduce the time in which the room is in a high humidity state.Mechanical ventilation can greatly reduce the relative humidity in the room while reducing the latent heat load of dehumidification,ensure PMV value between-0.5 and 0.5 to ensure indoor comfort.The greater the number of air changes,the more obvious the dehumidification effect.After considering the wet transfer of the envelope structure,the indoor average relative humidity is significantly increased.Testing the thermal and wet property parameters of domestic building materials,analyzing the influence of heat and moisture migration of building envelopes on building energy consumption and human comfort,the maximum difference in energy consumption in winter is 9.23%,the maximum difference in summer is 5.37%,and the total energy consumption under HAM algorithm is reduced by 3%-9%.The energy consumption is obvious.After considering heat and moisture transfer,the average value of PPD-PMV in Shenyang is 12.67%-0.48,the average value of PPD-PMV reaches 30.73%-1.27 at high personnel density,the temperature difference between the surface temperature of the enclosure and the indoor temperature is less than 5?,and the ratio of the relative humidity of the building in the three enclosures is greater than 70%.Reduced from 57%,56.89%,56.32%to 3.7%,6.02%,and 2.98%,respectively,the impact of human comfort is very obvious and accurately analyzing the thermal structure of the envelope structure is of great significance for realizing building energy conservation and improving indoor environment comfort.