INDUCTION RATIO OF ACTIVE CHILLED BEAMS IN REALISTIC OPERATING CONDITIONS

Abstract

This dissertation studies the performance of Active Chilled Beams (ACBs) in an office setting by utilising 8 airflow probes and 2 temperature sensors. ACBs are a type of indoor air-conditioning unit consisting of a cooling coil with fins and an integrated air supply. As opposed to a conventional air-conditioner unit which supplies cool air directly into an indoor space, an ACB induces indoor airflow to pass through its cooling coil to achieve cooling. ACBs are known for their energy efficiency, cost savings, and ability to improve thermal comfort for occupants. The ratio of the induced volumetric airflow to the supply airflow is the induction ratio (IR). The higher the IR, the more efficient an ACB is. Previous studies have been assuming a constant IR; that is, IR is independent of indoor conditions. However, this assumption may not be valid because real indoor conditions can be very different, for example, the size of the indoor space to be cooled, the number of occupants, et cetera. This dissertation project aims to examine the impact of actual operating conditions on the IR of ACBs in an office environment.

The findings of this study conclude that the scenario with the office door closed with no occupants has the lowest IR value of 2.78. In contrast, the scenario with the office door opened with the presence of occupants has the highest IR value of 4.25. The lowest IR value is approximately 1.5 times lower than the highest IR value obtained.