On-site measured performance of a radiant floor cooling/heating system in Xi’an Xianyang International Airport

• Performances of radiant floor (RF) cooling and heating in an airport are measured.
• High-T cooling and low-T heating are realized in the RF system.
• Cooling and heating capacity of the RF is 30–40 W/m2 and 30–70 W/m2 respectively.
• Cooling capacity of RF is improved to over 100 W/m2 with high-intensity solar radiation.
• The RF system provides a comfortable environment and improved energy-efficiency compared with jet ventilation.

In large space buildings such as airports, radiant floor systems are an attractive alternative to conventional all-air jet ventilation systems due to their advantages in thermal comfort and energy efficiency. This paper focuses on the operating performance of the radiant floor system in Terminal 3 of Xi’an Xianyang International Airport, the first airport terminal in China to adopt radiant floors for cooling. In summer, the typical cooling capacity of the radiant floor is 30–40 W/m2 with a mean chilled water temperature of 18 °C; this range increases to 110–140 W/m2 with solar radiation of 120–170 W/m2. The incremental effect of the solar radiation on the cooling capacity of radiant floor is analyzed with simple calculation methods. In winter, the radiant floor provides a heating capacity of 30–70 W/m2 with a hot water temperature of 35–40 °C, which is sufficient to satisfy the heating requirement. Compared with the jet ventilation system adopted in Terminal 2 of the same airport, indoor thermal comfort is significantly improved with the radiant floor system in Terminal 3 in both cooling and heating modes. Moreover, the novel system’s indoor air temperature distribution throughout the whole space and its utilization of high-temperature chilled water and low-temperature hot water reveal its potential for energy conservation.