Individually controlled localized chilled beam with background radiant cooling system: Human subject testing

This study examines the responses of twenty-four subjects to an individually-controlled localized chilled beam (LCB) and compares it to a mixing ventilation (MV) as the reference system. Both LCB and MV also used ceiling cooling (CC) panels for background cooling (forming LCBCC and MVCC systems). The LCB directed the supply air towards the subjects to create a micro-environment around them. Four experimental conditions were established using a combination of two room temperatures (26 \ub0C and 28 \ub0C) and two primary ventilation rates (10 l/s and 13 l/s). During the 90 min-long experiments, the subjects were asked to assess their perceived air quality, thermal sensation, comfort, air movement acceptability and acceptability of the work environment. The results indicated that the LCBCC was superior to the MVCC with significantly higher acceptability of the work environment, perceived air quality and thermal sensation. Perceived air quality and thermal sensation were rated near the “clearly acceptable” level for both room temperatures when LCBCC was used. Moreover, thermal sensation votes were close to the “neutral” level for room temperatures as high as 26 \ub0C and 28 \ub0C. The micro-environment established by the LCB was found to be resilient to changes in room temperature. With the MVCC, the thermal environment was rated as “slightly warm”. No major potential risk of draught among the subjects was reported when using the LCBCC. The findings of this study contribute to the development of high-temperature cooling systems in general, and localized ventilation systems in particular