Human response to thermal environment and perceived air quality in an office with individually controlled convective and radiant cooling systems

Abstract

The purpose of this study is to analyze the human response to the indoor climate with two individually controlled convective and radiant cooling systems: a low velocity unit combined with radiant panel system (LVRP) and a personalized ventilation system combined with a radiant panel system (PVRP). As a reference system without individual control, diffuse ceiling ventilation combined with a radiant panel system (DCV-RP) was also studied. In laboratory conditions, 10 males and 10 females gave subjective response to the indoor climate during various office activities. The indoor parameters and CO₂ concentrations were measured. The results show that with the reference DCV-RP system, the indoor conditions were worse than with the LVRP and PVRP systems. The thermal sensation and perceived air quality with the PVRP system was better than the LVRP system. After a medium activity task, the thermal acceptability reverts faster with the PVRP than LVRP system. Both the LVRP and PVRP systems were able to create a micro-environment around the workstations and the CO₂ concentrations near the workstation were slightly lower than at the exhaust grille. Compared with the PVRP system, the subjects preferred the higher airflow rate at the workstation with the LVRP system. Males preferred a higher airflow rate than females under the same conditions with both micro-environment systems. This research found that there was significant variation in the control preferences of the human subjects concerning the micro-environment, and this emphasizes the need for personalized control to ensure that all occupants are satisfied with the indoor conditions.