modelling

The paper describes work on simplified design methods made in connection with the International Energy Agency programme "Air Flow Pattern within Buildings", Annex 20, subtask 1. It is shown that simplified models are able to indicate design values as the maximum velocity in the occupied zone and penetration depth of a non-isothennal jet in a room. The design according to throw of an isothermal jet is a fully developed method which has a sufficient level of accuracy when it is used in regular rooms.

The subtask 2 of Annex XX (Optimization of Air Flow Patterns Within Buildings) involved a research project called "Air Flows Through Large Openings In Buildings". The scope of this project was to test the range of validity of available algorithms, and where possible to develop new ones. This paper focuses on the new interzonal airflow studies which have been carried out in this frame.

IEA Annex 23 has been established in order to attempt to resolve these difficulties in relation to multizone air flow modelling. These models are used to evaluate the air flow between individual rooms or zones as well as the rate of inflow andoutflow of air from buildings. This approach is especially important for evaluating the adequacy of ventilation, predicting pollutant transport and evaluating airborne heat transfer between zones. Such models therefore have vital applications in both energy and air quality related analysis.

The objectives were a) to evaluate performance of air flow models in predicting air velocity, temperature and contaminant concentrations; b) to evaluate applicability of models as design tools; c) to produce guidelines for their use. All the work is addressed to a single zone. It includes both numerical simulations and experiments for given configurations.

In this paper information is provided about ways to model the boundary conditions near the radiator for use in the flow simulation program. Due to lack of time the modelling is restricted to the thermal behaviour of a single plane radiator as selected in 'R.I. 1.4 : Selection of radiator'. Ways to model the flow near the radiator with e.g. hot and cold wall jets have not been investigated.