AIR CONDITIONING IN HIGH CARE FACILITIES FOR IMMUNO- SUPPRESSED AND IMMUNO-COMPROMISED PATIENTS

The objectives of an air conditioning system in a hospital reach much further than just promoting a comfortable environment. It is often of the utmost importance to obtain the right ambient conditions for proper treatment of the patient in order to obtain rapid physical recovery or to protect either the patient or the environment from contamination. For immuno-suppressed and immuno-compromised patients the air conditioning involves a control of temperature, of swift temperature changes, of pressure relative to the outside environment, of humidity, of ventilation, of air purity and particle deposit. The clean air, delivered to the room via a laminar flow type rectangular modular perforated face, falls on the patient and the sterile equipment. A diffuser ensures a unidirectional discharge perpendicular to the mounting surface. The airflow over the patient and through the room is thoroughly studied via CFD: the commercial FLUENT solves the RANS equations with a realizable k-ε turbulence model. The (thermal) boundary conditions applied to the CFD model are based upon a dynamic thermal calculation using TRNSYS.
The energy needs for these applications are enormous and therefore the equipment must be well designed, simulations are performed with TRNSYS. The maximum power is calculated both for summer and winter conditions. The considerate energy consumption pushes the design engineer in proposing advanced optimized solutions.
After determining the flow field, the assessment of particle deposition is executed. It is shown that the approach is meaningful with an acceptable computational effort, since the RANS solution allows for a safe prediction of the particle deposition.
Different injection clouds are simulated, each with a different diameter and with several repetitions to obtain a reliable average. An important part of the cloud is evacuated through neighbouring outlets, however some particles are dispersed and eventually escape through outlets on the other side of the room.