Research On The Natural Ventilation Of UFAD In A Elevated Railway Waiting Room

In the season of suitable climate, the best way to improve the indoor air quality, improve indoor thermal comfort and reduce building energy consumption is good natural ventilation. In the railway station waiting room and some other large space buildings with personnel intensive, serious air pollution and heavy cooling load, how to makes use of its abundant space to organize natural ventilation and extend its available time is more important.In the large space, large depth of Kunming railway station elevated waiting room, this paper presents a new approach to organize natural ventilation, which makes use of UFAD (underfloor air distribution) and introduces the outdoor air into the waiting room from the special transparent truss structure. Through the simulation of the indoor wind field and temperature field by using the CFD simulation software, the author analyzes the effectiveness and superiority of this ventilation methods.While under the condition of different outdoor temperature, this paper defines a range of acceptable indoor temperature of80%passenger—Adaptive Thermal Comfort Models. The author also studies the influence of the outdoor temperature, the indoor heat source and the electric sunroof area to the seating area temperature respectively. Laying a foundation for how to adjust the controllable electric sunroof area to make indoor temperature back to the acceptable temperature range, when outdoor temperature or indoor heat source changed.Finally, this paper discusses the opening rules of the electric sunroof of the Kunming railway station waiting room and establishes the adjustable model of the electric sunroof in daytime and nighttime, from which we can get the adjustable range of the electric sunroof when the outdoor temperature changed, by adjusting the model could get power sunroof adjustable range, meanwhile we can determine the allowed range of the outdoor temperature by making use of the electric sunroof to adjust the seating area temperature separately. During the day for example, when the electric sunroof area of a quarter of the waiting room is changed in9.44m2to50m2, in order to let more than90%passengers satisfied with the indoor thermal comfort environment, the outdoor temperature is allowed to vary in the range of15.94℃to23.67℃. In Kunming annual outdoor temperature in this range for more than seven months, further demonstrates the great potential of using the natural ventilation and the practical value of the new approach to organize thermal natural ventilation in mild and hot summer and warm winter areas.