Numerical study on indoor environment and thermal comfort in train station waiting hall with two different air-conditioning modes

With the increasing size of the waiting hall, the large-area use of transparent envelope materials makes the interior surface temperature of the envelope too high, which puts forward higher requirements for the control of environment and thermal comfort indoors. In this paper, the characteristics of indoor temperature distribution, relative humidity distribution and thermal comfort under the all air system (AAs) and the radiant floor cooling and wall cooling combined with air supply system (RC/ASs) were investigated in the large spaces. The computational fluid dynamics (CFD) method was used, and the performance of the CFD model was validated by comparing the measured results with CFD simulation results in the AAs. The numerical results clearly showed that the temperature and relative humidity indoors could satisfy the design requirement both in the AAs and RC/ASs. The indoor air distribution in most areas under the RC/ASs was more uniform based on the indoor heat and humidity requirements under the cooling load of measured day. In the AAs, the total cooling capacity of air conditioning unit was the highest when indoor thermal comfort was the best, that meant that to achieve the best working condition, the air-conditioning system need high energy consumption. Meanwhile, the RC/ASs addressed the problem that the temperature around the seated passengers in the waiting area was relatively high in the AAs. This paper will provide reference for the air conditioning system design in the similar large spaces in the future.