Thermal Comfort Study of an Under-Floor Air-conditioning System

This paper reports a thermal comfort study of an under-floor air-conditioning (UFAC) system in hot and humid climate. Thermal comfort parameters were measured at predetermined grid points within an imaginary plane to predict the airflow pattern of the supply air jet as well as to determine the occurrence of thermal stratification in the office space. Fanger's thermal comfort index was also computed to detect the occupants'thermal sensation. Statistical methods were applied to derive the relationship between air velocity and the other parameters. The main findings from the study reveal that with the UFAC system, occupants are likely to experience localised thermal discomfort near the supply diffusers due to the existence of large temperature gradients. In addition, a stagnant zone is discovered at sedentary level, which is caused by the parabolic airflow nature of the primary air jet.