Thermal Performance And Indoor Thermal Environment Characteristics Of Wall Roof Combined Heat Storage Ventilation Wall

Qinghai Tibet Plateau and Northwest China have a long winter and cold climate,but there are abundant solar energy resources.Local residents have rich experience in using solar energy to improve the indoor thermal environment of residential buildings,such as using glass houses as sunlight to improve the indoor temperature in the daytime.However,the glass curtain wall has a lot of heat gain in the daytime,but also a lot of heat loss problems at night,and the indoor temperature fluctuates violently.From the point of view of the effective utilization of solar energy,the effective heat gain in daytime should be increased,while the large amount of heat loss at night should be reduced.Therefore,this study aims at the South structure of the wall roof integrated all glass curtain wall,and improves the inner wall structure of heat storage ventilation in order to comprehensively improve the thermal performance of a large number of existing glass curtain wall structures.In this paper,according to the wall roof combined heat storage ventilation wall structure,through the analysis of the heat transfer process of the wall roof combined heat storage ventilation wall and air circulation,the heat balance equations of glass curtain wall,sloping roof,air in the passage,surface of heat absorbing coating,internal surface of heat storage are established;the mathematical equations of indoor air and wall heat balance of this kind of heat storage ventilation wall are constructed;taking Lhasa as an example,through a large number of numerical simulation and experimental verification methods,this paper analyzes the influence of roof tilt angle,ventilation hole size,passage thickness,fan wind speed on the thermal performance of wall roof combined thermal storage ventilation wall,obtains the optimized structure and operation parameters,and summarizes the simplified calculation method of heat under different roof tilt angles.The main results are as follows:(1)With 45 ° as the reference line,when the roof inclination angle is greater than or less than 45 ° and the same angle,the outlet temperature is similar;when the daily average total heat supply is 45 °,the maximum value appears.With the increase of the vent size,the outlet temperature decreases and the decreasing range decreases gradually;considering the total heat supply and convective heat exchange,the vent size of 250 mm × 250 mm is the best.With the increase of channel thickness,the outlet temperature first decreases and then increases;considering the influence of heating capacity and economy,it is suggested that the channel thickness is 100 mm.(2)From 9:00 to 4:00 of the next day,the outlet temperature decreased with the increase of fan wind speed,but in the period of 4:00 to 9:00,the outlet temperature showed the opposite trend.When the wind speed of the fan is 1.0 m/s,the daily average total heat supply reaches the maximum value,and the outlet temperature is high,so there is no cold air feeling.It is recommended to open the ventilation hole of the wall roof combined heat storage ventilation wall during 9:00-24:00,and close the ventilation hole in the rest time.According to the distribution of solar energy resources and the division of climate zones in the Qinghai Tibet Plateau and the northwest of China,the typical areas are selected to study the influence of wall roof combined thermal storage ventilation wall on indoor thermal environment and its energy-saving effect.The main results are as follows:Taking Lhasa,Xining and Xi’an as examples,it is found that the outlet temperature of the wall roof combined heat storage ventilation wall is similar to the total heat supply.In Lhasa and Xi’an area,the natural room temperature of the wall roof combined heat storage ventilation wall room can meet the indoor requirements for about 3.5 hours and 6 hours,respectively.It can meet the human comfort requirements in the period of 13:00-17:00,and the rest of the time still needs to add auxiliary heat source.The fluctuation of room temperature in Lhasa area reduced by about 3℃,and the temperature difference between day and night decreased obviously.Compared with the traditional glass curtain wall,the effective heat gain of the wall roof combined heat storage ventilation wall room is significantly improved,and the heat gain time of the heat storage ventilation wall room in Lhasa and Xi’an area is extended by about 3.5hours and 4 hours;the heat load of the ventilation wall room in the two areas is greatly reduced,about 40.7% and 38.2% respectively,but the energy saving effect in the daytime is better than that in the night.In general,the ventilation wall is more suitable for the solar energy enrichment area.