Experimental study on the performance evaluation of active chilled beams in heating and cooling operation under varied boundary conditions.

This study investigates the thermal comfort, airspeed and temperature distribution, air change effectiveness and importance of the boundary conditions on the selection and performance of Active Chilled Beams (ACB). Many past studies in cooling confirm that the thermal comfort is satisfactory because the temperature gradient and airspeeds are acceptable at the occupant level without addressing the local discomfort. Similarly, no known study was found to address thermal comfort in heating. This paper reports the results of an experimental study that addresses such issues. A laboratory experiment, simulating a multi-occupant open office with an ACB subjected to different boundary conditions, was conducted. The heating test results demonstrate that there is a risk of discomfort due to radiant temperature asymmetry. It also shows no airspeed in the occupied zone, which reduces the air change effectiveness. The cooling test results demonstrate that discomfort draft risk at the ankle level is higher in ACB parallel to window configuration. The results suggest that shape and throw of ACB affect air distribution and emphasize the importance of properly selecting, orienting, and designing ACB, not just to offset the room loads, but to match the proportions and boundary conditions of the space. [ABSTRACT FROM AUTHOR]