Chilled beam systems provide sensible cooling in the occupied space using chilled water flowing through modular beams mounted to a ceiling. Chilled beam systems can achieve cooling energy saving larger compare to all-air system due to greater thermal energy delivered by the chilled water than air, and thus are well-suited for spaces with relatively large sensible cooling loads as an energy-saving method. The objective of the present study is to study air conditioning performance of combined passive chilled beam (PCB) - displacement ventilation (DV) systems. Using computational fluid dynamics (CFD) simulations, the amount of sensible cooling by PCB and its impacts on ventilation effectiveness and thermal comfort in a typical office room are investigated. Simulations for combined PCB-DV system under different cooling load and ventilation conditions are conducted to study the system performance. The study results reveal that the thermal and ventilation performance can vary significantly with type of ventilation strategy, type of air supply diffuser, PCB cooling output and supply air temperature. However, arrangement of heat sources has a marginal effect on the performance of combined PCB-DV systems. With a PCB cooling output of 50% of the total cooling load and the supply air temperature of 19-20 ℃, the combined PCB-DV system can achieve the best performance in terms of energy use, ventilation effectiveness, and occupant thermal comfort.
