Study On Night Ventilation Strategies Affected By Heat Storage Characteristics Of Ultra-Low Energy Consumption Building Walls

Passive ultra-low-energy buildings(hereinafter referred to as ultra-low-energy buildings)with good thermal performance of envelope structure,strict air tightness and no heat bridge design and fresh air system with heat recovery,can achieve energy-saving,comfortable and healthy indoor environment without air conditioning and heating equipment.In order to make full use of the excellent thermal performance of ultra-low energy consumption building walls,this paper takes " Fivewin Room Exhibition Hall",the first demonstration project of ultra-low energy consumption office buildings in Zhengzhou City,Henan Province,as the research object,and studies the night ventilation strategy under the heat storage characteristics of ultra-low energy consumption building walls in Central Plains.Based on the analysis of unsteady heat transfer and the influencing factors of wall heat storage,this paper uses Energy Plus building energy consumption simulation software based on conduction transfer function method and heat balance method to simulate and calculate the unsteady heat transfer process of ultra-low energy consumption building walls.And then,the variation law of wall temperature and indoor air temperature in the whole year under the construction of external and internal insulation walls is obtained.The data analysis shows that the indoor temperature of the two types of insulation wall increases by about 9?under the action of internal disturbance,and the internal disturbance has a great influence on the inside temperature of the wall and indoor air temperature of the insulation wall.For the whole year,the external thermal insulation wall shows better thermal stability.In winter,External thermal insulation wall in winter with heating equipment to assist heating time only accounts for 9% of the whole winter.However,the natural room temperature in transition season and summer can not satisfy the thermal comfort of office staff during office hours for most of the time,so passive cooling technology is needed to reduce the room temperature and improve the comfort of indoor thermal environment.Summarizing the wall temperature,natural room temperature and heat storage characteristics of ultra-low energy consumption wall,and then studying on the night ventilation strategy of transition season and summer in the form of external thermal insulation wall,which has good thermal performance.The results show that the better indoor thermal environment can be achieved when the night ventilation air change rate are 3 times per hour,5 times per hour,5 times per hour,3 times per hour and the ventilation time is 18:00 on the same day to 08:00 on the next day in the transitional season.Night ventilation without air conditioning in summer can reduce the natural room temperature by about 7?.10 times per hour of night ventilation under air conditioning can reduce the refrigeration energy consumption to the greatest extent.Night ventilation time in summer should be from 20:00 on the same day to 06:00 on the next day,and the optimal ventilation air change rate should be 10 times per hour.