The predominant route for air movements between the floors of two-storey dwellings is via the stairwell. Such air movements are of significance in the assessment of building performance: for instance, it is possible that moisture could be transferred from ground floor areas to rooms on the first floor, resulting in an increase in condensation risk in such rooms. Several domestic heating schemes have been designed such that heating appliances are provided on the ground floor only; the upper floor relying on convective airflows for heating.

With a dynamical model, the thermal behavior of a single office room is simulated. The model includes among other things the behavior of occupants, the heat production of machines and lights, the heat flux into masses, real weather data (hourly observations) and different HVAC and control systems. The computer program calculates monthly and yearly energy consumption and a statistical distribution of the room air temperature. It can also be used to investigate the time evolution of physical processes for short periods.

As part of the IEA Research Program Annex 18 "Demand Controlled Ventilation Systems" various ventilation systems were examined in a test room. During research, in addition to thermal comfort issues, removal of particles was of importance. In order to assess ventilation systems, besides using pressure - volume current graphs, the air exchange rate was frequently applied as a criterion. The air exchange rate is, however, defined only for gaseous components.

A new facility for the study of ventilation in buildings has been recently developed at the University of Basilicata (Potenza, Italy). This facility consists in a Controlled Ventilation Chamber (CVC), with an overall size of 2.4*2.4*3.0 m (the length may be extended to 4.2 m) . The CVC is divisible in two parts with a connecting door and is equipped with four grilles from which air can be immitted or extracted. A variable speed fan can adjust a flow rate of 0 to 10 ach.

A new European norm for measuring the heat transfer rate of radiators is under discussion [ CEN TC 130 ]. This testing can be done either in a closed chamber with cooled walls or in a open chamber with a controlled air supply. The air flow pattern around a typical radiator is calculated for both types of chambers. The calculation is done with the program PHOENICS, a finite volume program that solves the conservation equations for mass, momentum and energy. For turbulence, the k-E model is used with the Lam-Bremhorst correction for low Reynolds numbers.

An investigation has been carried out using computational fluid dynamics methods to study the performance of an air curtain at the door of a heated building. A number of operating conditions have been studied and observations are made on the effectiveness of infiltration control and energy use. Comparisons are also made with previously published design data and results from an accepted infiltration analysis. It is shown that the calculation method generates plausible and very detailed results which conform well to physical interpretation.

This paper presents some of the early theoretical work conducted within the framework of a research program aimed at analysing the interaction between gas-fired domestic appliances and the indoor environment in terms of energy consumption, indoor air quality and operational safety. A simplified multizone mathematical model has been developed, which is capable of analysing the thermo-fluid dynamics behaviour of the building + appliance + chimney system.

An appropriate way to identify the most efficient ventilation systems and improve their design is to use design codes for ventilation rates. These rates are strongly influenced by spatial and temporal fluctuations in wind pressure on the facade and roof. The influence of the effects of wind on ventilation was studied using a model which includes air compressibility, together with the pressure field measured on a model in a boundary layer wind tunnel. The simulation results obtained are analyzed using a design code.

This paper treats the structure of models for predicting interzonal airflow and contaminant dispersal in buildings. It will discuss the mathematical structure of such models, the use of modem data structures, the application of structured program techniques and the use of object-oriented structures for the development of users interfaces and building description processes.

Ventilation efficiency may be defined as the capability of a given ventilation system to achieve the best balance between indoor air quality and energy conservation requirements: