Application of a new method for improved multizone model predictions.

Multizone models are a common tool for calculating air and contaminant exchange within rooms of a building and between building and outside. Usually a whole room is then modelled by one calculation node with the assumption of homogeneously mixed conditions within this room. In real cases, however, temperature and contaminant concentrations vary in space. The exchange to the neighbouring nodes via the flow paths is then a function of the local values of these variables. Detailed knowledge can be obtained from the solution of the transport equations for the air flow pattern within the room at the expense of higher computation cost. This work shows the application to several examples of a new method which includes results from detailed calculations for one room of importance in a multizone model of a whole building. The examples with air in/exfiltration, ventilation and contaminant propagation show the effects on the results of the prediction of the air flow and the contaminant spread by relaxing the homogeneity assumptions. The proposed name of the method is "Detailed flow path value method" (DFPV method) as separate local variable values are considered for each flow path h m the room of importance to the neighbouring rooms instead of one average value. It is discussed in which situations the DFPV method can be expected to improve the multizone model predictions.