Numerical investigation of the thermal and ventilation performance of a combined impinging jet ventilation and passive chilled beam system

Impinging jet ventilation (IJV) systems provide high ventilation efficiency and good indoor air quality (IAQ) in the cooling mode. However, they have a limited cooling capacity. Passive chilled beam (PCB) systems are widely used in indoor environments with high cooling loads and can potentially address the limitation of low cooling capacity of IJV. In this study, the possibility of combining IJV and PCB systems is investigated using computa-tional fluid dynamics (CFD) simulations. The effects of two main factors, namely the percentage of cooling load removed by the PCB system (eta) and supply air parameters (Lm) of the IJV system, on the thermal and ventilation performance of the IJV-PCB system are examined. The results indicate that the PCB system enhances the mixing of indoor air and effectively reduces the vertical temperature gradient in the IJV room. An optimal range of eta that improves the cooling capacity and maintains the high ventilation performance of IJV is determined. This range for an IJV-PCB system is 0.15 < eta < 0.45, considering thermal comfort, IAQ, and energy saving potential. In addition, the IJV-PCB system offers a wide selection range for Lm (0.4-1.2) compared with that of the IJV, and a high ventilation efficiency and good IAQ are maintained in the room in this range.