13. Air-Condition and Refrigeration

The implementation of effective ventilation systems in operating rooms is crucial for maintaining a sterile environment and reducing the risk of bacteria-carrying particles (BCPs). A comparison of several types of ventilation in hospital operating rooms indicates that the temperature-controlled airflow (TcAF) system represents a reliable and effective ventilation method and can serve as an energy-efficient alternative compared to others. However, to further optimize the performance of this ventilation system, a study on several influential input variables is necessary. This research compares two case studies of operating rooms both utilizing the TcAF ventilation system, with the difference being the position of the exhaust diffusers. In each case study, tests were conducted on various input values, including three different Central Inlet Diffuser Velocities (0.20 m/s, 0.24 m/s, 0.28 m/s), Peripheral Inlet Diffuser Velocities (0.14 m/s, 0.17 m/s, 0.20 m/s), and Central Inlet Diffuser Temperatures (18°C, 20°C, 22°C). The study is conducted using Computational Fluid Dynamics (CFD) and Lagrangian Particle Tracking (LPT), with numerical models validated against literature data. The results reveal that the position of the exhaust diffuser is not sensitive to changes in BCP concentration, whereas variations in input variables show that an increase in Central Inlet Diffuser Velocity significantly reduces BCP concentration, similar to the effect of lowering the Inlet Diffuser Temperature. Additionally, an increase in Peripheral Inlet Diffuser Velocity also contributes to a reduction in BCP concentration, albeit less significantly.