Ventilation, infiltration, indoor air flows and air exchanges determine two aspects of fast growing interest: the energy balance of buildings and the indoor environment. Whilst in the wages of the energy crisis RD (research and development) & D (demonstration) in the different areas had been focused on rational energy use now with view on the public awareness of the environmental situation (outdoors and indoors) also the aspect of indoor air quali ty stimulates widespread RD&D activities.

This paper explores the results of air infiltration and ventilation research carried out in Canada over the last decade and specifically examines its application to low-rise residential buildings. With Canada's cold climate, the reduction of space heating costs by dealing with air infiltration and ventilation issues in residential buildings is particularly important and has been the subject of government and industry initiatives. The results over the last decade have been gratifying.

The COMIS workshop (Conjunction of Multizone Infiltration Specialists), using a multi-national team, is planning to develop a reliable, smooth running multizone infiltration model on a modular base. This model not only takes crack flow into account but also covers flow through large openings, single-sided ventilation, cross ventilation and HVAC-systems. The model contains a large number of modules which are peripheral to a steering program. COMIS can also be used as a basis for future expansion in order to increase the ability to simulate buildings.

A tracer gas technique for determining volumes and air flow rates in multi-cell systems with a single tracer gas is considered. Tracer gas is injected in all cells simultaneously according to a cetain pattern and the resulting tracer gas concentrations are recorded. We show how the volumes and flow rates can be identified from the measurements using the quadratic programming method. A characteristic of this method is that the unknown model parameters, i.e. the volumes and flows, can be determined subjected to given constraints.

VAV - air conditioning system makes it possible to control indoor conditions even when the heat loads are changing. But this is possible only when each part of the system works as it is intended to work. When the air flow varies in a large range, it can cause situations, where pressure loss of some flow dampers are out of their operating range. This is possible especially whenthe system is large and the velocities are high. This means that the air flow is not correct. Also increasing noise levels may appear.

This paper describes a simulation program which was developed for the modelling of air-conditioning systems and conditioned spaces in industrial buildings. The program can be used for a design of systems for new buildings and for analysis of existing ones. By viewing the building as a dynamic entity, it is possible to investigate how thermal capacity of the building elements acts on both the conditioned space and the performance of the air-conditioning system. The program simulates three important aspects of a building.

This paper describes an experimental study of the buoyancy-driven flow and the associated energy transfer within a closed, halfscale stairwell model. It provides new data on the velocity, temperature, volume and mass flow rates of the air circulating between the upper and lower storeys. The results are presented for various heat input rates from the heater, located in the lower floor. For most of the data presented, heat transfer to the surrounding atmosphere takes place through the side walls.

This paper deals with the elaboration and the validation of a userfriendly numerical program (EOL) for the calculation of the ventilation patterns inside industrial premises. After the running-in. In period, "EOL" will be used by the technical staff in charge of ventilation projects. Here is set out the EOL unit devoted to the calculation of the mean flow inside the rooms. The structure of the software (presently restricted to two-dimensional mean flow configurations) is explained.

The paper compares air infiltration rate measurements with air leakage measurements in a modem industrial building. In each case the tests have been performed firstly with the building 'as-built', and then with the major leakage components sealed. The building investigated was of a cladding wall construdion with U-values of 0.6 W.m^-2.K^-1 for both the walls and roof. It had a floor area of 466 m². The volume was 3050 m³. Tracer decay tests and constant concentration methods (both using N20) were performed in the building to establish the air infiitration rates.

In the "Stockholm Project", different blocks of multifamily buildings have been extensively monitored for about three years. Temperatures, airflows and electricity use have been registrated each hour. As an additional base to this examination, ten fan units in the buildings have been intensively studied. The results show that the specific use of power for transportation of ventilati n air varies between approximately 1 and 4 kW per m³ and second. The results from the measurements indicate a notably low level of installation efficiency.