Performance investigation of indoor thermal environment and air handling unit in a hub airport terminal

Airport terminal is a typical large space building with large high interspaces and multitudinous functional zones. The task of heating, ventilation and air conditioning (HVAC) system is to ensure the thermal environment of these zones with different functions. A typical terminal in cold region of China is investigated in present paper, where indoor environment and performance of air conditioning system in summer are emphasized. The results indicate that the indoor temperature and humidity parameters at a height of 1.5 m in each zone of the terminal can be effectively controlled. The indoor temperature at a height of 1.5 varies in the range of 24~27°C, and the temperature difference is 0.5~4.9°C in the vertical direction. The temperature at the top of the terminal is greatly affected by the outdoor temperature where is higher and fluctuates obviously, while the temperature at the height of the occupant area is lower and more stable under the control of the air-conditioning system. The indoor carbon dioxide concentration is also at a reasonable level, all below 900 ppm, indicating that the equivalent outdoor air volume per capita is greater than 35 m3/h. Even in the case of high load caused by flight delays, the thermal environment in the terminal can be basically controlled at a comfortable level. As for the air handling unit, air handling process is tested to investigate the cooling capacity. The results show that the actual water supply of the AHU is relatively higher than the set value, but the air volume is almost equal to the set value which leads to an unsatisfactory energy efficiency. The tested energy efficiency ratio (EER) of AHU is only 5~7, almost approaching to that of the cooling plant. Reducing air flow rate could greatly improve the EER of the current air-conditioning system.