Natural Personalised Ventilation for Hospital Wards: Experimental Validation

Session 4, Paper 1, CIBSE ASHRAE Technical Symposium, Dublin, Ireland, 3-4 April 2014

Personalised ventilation (PV) systems are useful in protecting vulnerable hospitalised patients from airborne infection due to localised delivery of clean air. A natural personalised ventilation (NPV) system has previously been shown to be a feasible, natural and low-energy alternative to mechanised PV systems. The original NPV system was investigated using three conceptual designs which used dynamic thermal modelling and steady-state computational fluid dynamics to simulate a single-bed hospital ward. Findings from these designs led to optimisation of the NPV system components (stack and ducts) which also serve as the basis for this experimental validation. The objective of this research is to validate the flow characteristics of the optimised NPV system using scaled model experiments in addition to computational fluid dynamics (CFD) studies. Water-bath modelling (WBM) was carried out in a large Perspex tank and a scaled version of the single-bed ward was also constructed in Perspex. Results improve our understanding of the proposed NPV strategy, in particular showing that different locations of heat sources within the model leads to considerably different internal temperatures at steady state. Close similarities between CFD and WBM simulations were also observed.