A model of a displacement ventilation system suitable for system simulation

There is increasing interest in Europe in the use of displacement ventilation and chilled ceiling coolingsystems. A modelling methodology is presented here that deals with the significantly different heat transfer characteristics of these systems compared with conventional all-air systems. The purpose of the work is to develop a room model that is computationally efficient enough for annual hourly simulation purposes and a nodal model has been developed that is intermediate in complexity between a single air node model and a CFD model. Results of steady state comparisons of the model predictions and test chamber measurements are presented. A cooling system employing indirect evaporative cooling anddisplacement ventilation has been simulated using the model, and is included as an example, of the simulation methodology. The model can also be extended to treat systems with chilled ceiling panels.