Induction ratio of active chilled beams

In active chilled beams, primary air from the air handling unit induces room air which passes a coolingcoil before it mixes with the primary air and discharges into the room. The ratio of induced room air flowto the primary air flow is the induction ratio (IR). Knowledge about the IR is important when modellingcooling capacity as well as temperature and velocity of the air discharged from the beam.Most previous studies of the behavior of IR are focusing on the influence of primary air flow. The purposeof the work presented in this paper is to investigate whether other operating conditions also influencethe IR. Three methods of determining the IR are compared in order to strengthen the conclusions.The results indicate that the IR is influenced by the chilled water temperature due to buoyant forces.Novel methods of determining the IR are presented and it is concluded that current methods may leadto overestimation.

Energy and Buildings 129 (2016) 445–451

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