A review of impinging jet ventilation for indoor environment control

Impinging Jet Ventilation (IJV) has emerged as a promising strategy for indoor environmental control, offering an alternative to conventional such as Mixing Ventilation (MV) systems. This review critically examines the performance of IJV in terms of thermal comfort, indoor air quality (IAQ), energy efficiency, and design flexibility, with a broader focus on the system implementation and a particular focus on office environments under moderate heating and cooling loads. The focus of the review is to compare the IJV system with the MV system. In comparison to MV, IJV delivers conditioned air to the occupied zone more effectively by providing stratified, low-mixing airflow and requiring a lower airflow rate to maintain acceptable thermal comfort conditions. This results in improved thermal comfort, reduced energy usage, and enhanced pollutant removal. The system also facilitates thermal stratification and supports higher supply air temperature differentials, allowing for increased energy savings without compromising comfort. The review explores key performance metrics such as Predicted Mean Vote (PMV), Predicted Percentage of Dissatisfied (PPD), draught rate, and ventilation effectiveness, highlighting the conditions under which IJV outperforms MV. Additionally, challenges such as sensitivity to diffuser configuration, nozzle placement, and return vent positioning are addressed. The paper also evaluates recent advancements, including the integration of Internet of Things (IoT) technologies, machine learning, and hybrid systems combining IJV with passive or personalized ventilation. Despite its advantages, IJV remains underutilized due to design complexity and lack of standardizations. To enable broader adoption, future research should focus on simplified modelling tools, performance-based design standards, and scalable applications for various building types. Overall, IJV represents a viable, energy-efficient solution for modern ventilation design, particularly in environments requiring high indoor air quality and localized comfort control.