Influence Of Trombe Wall On Indoor Thermal Environment Of A Two-story Building

With the increasing awareness of energy issues,the energy conservation and environmental protection has gradually received wide attentions of various countries.Building energy consumption accounts for a large proportion of total social energy consumption.There are many problems such as irrational building structures,and high energy consumption affecting China's economic development.Using solar energy and enhancing natural ventilation,the Trombe wall structure has achieved ventilation and insulation in summer and winter.It is of great significance for alleviating energy pressure and promoting the development of eco-friendly buildings.In this paper,a double-deck test building with a Trombe wall structure in Qingdao will be exemplified,which takes a kind of common double-deck building in rural areas as a model.In summer and winter,based on the measurement and analysis on the parameters of the thermal environment inside and outside of the test building,conclusion can be drawn that in summer,the indoor temperature and wind speed as well as the solar radiation intensity show the same trend,which increases first and then decreases.At that time,the indoor temperature is lower than outdoor and the difference in temperature is about 1°C to 2°C;the upper temperature is lower than the lower temperature with the difference about 0.5°C to 1°C,and the solar radiation around13:00 peaks at 1083W/m~2.In terms of indoor wind speed,it will reach above 0.4m/s when the solar radiation is high in summer.In winter,the indoor and outdoor temperature is contrary.The hot-pressing effect of the Trombe wall structure is better observed with the sun appearing.When there is intensive solar radiation(10:00-14:00),the indoor temperature is 9~10°C higher than the outdoor temperature,and the temperature in the upper layer is about 0°C to 1°C higher than it in the lower layer.So the Trombe wall structure can effectively improve indoor ventilation and lower the indoor temperature in summer;in winter,it tends to increase the indoor temperature.Particularly when the solar radiation is strong,the hot-pressing effect of the Trombe wall structure is more obvious.According to the data of the experiment and using Fluent,data analysis on the double-deck building with Trombe wall structure in summer and winter is provided.There are the same trends between the results of data analysis and experiment in summer and winter.The error ranges are less than 6.8%and 12%respectively.The simulation method is correct.The temperature in most indoor areas is maintained at about 20°C.The wind speed in the main area of the indoor lower floor is about 0.1 m/s,and it is about 0.05 m/s in the upper floor.The temperature of a room with a Trombe wall is about 0.5~3°C lower than that of a normal room.Therefore,Trombe wall structure can better improve the indoor thermal environment of a double-deck building in summer.In winter,the upper air velocity of the double-deck building is higher than that of the lower storey.The air velocity in most areas of the room is maintained at about 0.1m/s to 0.2m/s;the upper temperature of the double-storey building is higher than the lower storey.The indoor temperature of the upper storey is about 6°C to 9°C higher than the outdoor temperature.Compared with the temperature of ordinary rooms,it has increased by 2.25°C to 9.65°C in the rooms with Trombe wall structure in the simulation experiment.So it can be seen that the Trombe wall structure can effectively increase the indoor temperature.According to thermal comfort theory and PMV-PPD index calculation system,the thermal environment of a two-deck building with a Trombe wall structure in summer and winter was analyzed.The results show that the general trend of the PPD index is similar to that of the PMV index in summer,increasing first and then decreasing.It is the most comfortable before 11 o'clock in the morning and after 4o'clock in the afternoon,and is still hot in the rest of the time.The thermal comfort of the lower layer is superior to the upper layer.In winter,the PMV increases first and then decreases.Between 9:00 and 11:00,the PMV is less than 0,and the thermal sensation is slightly cool.Between 11:00 and 15:00,the PMV value is positive,and the thermal sensation is slightly hot.The PMV is less than 1 during 15:30 and 18:00 with the lowest number-1.26,and the thermal sensation is cooler,and the upper PMV is greater than that of the lower layer.The PPD index first decreased and increased,and then decreased and increased,varying from 5%to 55%.Therefore,it can be seen that in summer and winter,the Trombe wall structure can effectively improve the indoor thermal environment and enhance the thermal comfort of the human body.