Impact of ventilation system type on indoor thermal environment and human thermal comfort in a ceiling cooling room

Abstract

A ceiling cooling (CC) system integrated with a mechanical ventilation system is an advanced HVAC system for the modern office building with glass curtain wall. In this paper, considering the influence of heat transfer of external envelope, the indoor thermal environment and human thermal comfort were objectively measured and subjectively evaluated in a CC room with mixing ventilation (MV) or underfloor air distribution (UFAD). Indoor physical parameters and human skin temperatures were measured as the chilled ceiling surface temperature and supply air temperature were 17.1-17.6? and 22.2-22.6?. Simultaneously, 16 subjects (8 males and 8 females) were selected to subjectively evaluate the thermal environment. The results showed that the difference between mean radiant temperature and air temperature in the occupied zone was 0.8? with CC + MV and 1.2? with CC +UFAD, and the indoor air velocity was 0.17 m/s with CC + MV and 0.13 m/s with CC + UFAD. In addition, the calculated and measured thermal sensation votes with CC + MV were all slightly less than those with CC + UFAD. Therefore, ventilation system type had a slight impact on the indoor thermal envi?ronment and human thermal comfort in the CC room.