Study On The Effect Of Tunnel Wind On Natural Ventilation Of Office Building

Energy problem is an important problem facing every country, and also one of thefour surviving problems facing human beings. The building energy consumption takesup a large proportion of total energy consumption, which concludes heating, airconditioning, ventilation, hot-water, lighting, elevator and so on. Building energysaving has already become one of important aspects for social sustainabledevelopment.Natural ventilation with underground duct system is an effective measure torealize building energy conversation. Natural ventilation can improve indoor thermalenvironment and air quality, meanwhile, save energy and promote social sustainabledevelopment, which accords with the idea of green building. Underground ductsystem equivalents to an air-soil heat exchanger, which reduces air condition energyconsumption according to stored natural cooling and heating by soil. In buildinginterior, air enters indoor through underground duct, then discharges outdoor form thetop open with the thermal buoyancy lift generated by the heat source, such as solarradiation, office equipment, and people. Outdoor air enters indoor after undergroundduct has better effect than directly enters indoor, as a result of the wall temperature islower than outdoor air temperature.The paper took an office building in Tianjin as an example. Air temperature ofcross section of underground duct, indoor temperature, temperature of skylight exportand air volume were measured. The air cooling effect in underground duct and afterentering indoor were analyzed. According to study, the relationship between airvolume and air density difference of skylight export and outdoor is determined.The FLUENT is used to simulated air cooling effect in underground duct whenoutdoor temperature was the highest in spring and autumn. The conclusions could bereached through simulation analysis: air temperature of underground duct export wasconstant with the change of outdoor temperature no matter when it was the hottest intransition season. Because of small temperature difference of skylight export andoutdoor, air volume caused by hot pressing was low, the air changes were less than1h-1. Nonetheless, indoor air cooling effect was good because the air temperature supplied was low. After the system operated for7h, soil temperature could beincreased. But when the system stopped operating, the soil temperature couldgradually recover to the original value during the following17h, which would noteffect on the next air cooling effect.