English

The AIVC nowadays is an established Centre on infiltration and ventilation research. It is well known throughout the world. This position has not been reached easily. But years of hard working and critical managing of the Centre were a necessity. Goes on to discuss the future development of the Centre.

Displacement flow systems are becoming popular, especially in Scandinavia, for comfort ventilation. In these systems air is supplied near the floor at low velocity; the temperature of the supply air is a few degrees below that of the air in the room. The supply air is heated by persons and/or machinery in the room. Turbulent plumes are formed above these heat sources.

Canadian research into residential ventilation and combustion venting revealed that the installed performance of exhaust equipment, ducting passages, and site-built chimneys was largely unknown. It became necessary to establish actual characteristics in order to be better able to predict the safety and effectiveness of various ventilation measures. For this reason, Canada Mortgage and Housing Corporation (CMHC), the federal agency responsible for housing policy, had a research device designed and fabricated.

The air exfiltration part of ventilation is often difficult to determine and its part of the energy balance is therefore usually determined as a remainder or given a constant value. This paper examines ventilation systems in six different modern houses. The constant concentration tracer gas technique tended to underestimate the total ventilation. A simplified theoretical one-zone model made accurate estimations of the air exfiltration. For detailed information on air flows a multi-zone network model was useful.

During the past decade a multitude of diagnostic procedures associated with the evaluation of air infiltration and air leakage sites have been developed. The spirit of international cooperation and exchange of ideas within the AIC-AIVC conferences has greatly facilitated the adoption and use of these measurement techniques in the countries participating in Annex V. But wide application of such diagnostic methods are not limited to air infiltration alone.

A method is being developed for visualization of air flow with application to the indoor problems of heating, ventilating and air conditioning. Photographic images of the soap bubbles seeded in space reveal features of the flow which can be quantified by the digitizing operations. Determination of the velocity vector field from the experimentally recorded images is possible.

Rising moisture from the ground has caused quite a lot of damage on foundations of Swedish buildings. It is in some constructions possible to prevent this by mechanical ventilation below the floor or below the concrete slab. This paper will present a model for coupled air flow and heat conduction for mechanically ventilated foundations. The presented model uses analytical expressions for the air flow in an air-permeable layer below a rectangular building. Analytical double-periodic functions of elliptic type are used.

The paper describes the development in airflow simulations in rooms. The research is, as other areas of flow research, influenced by the decreasing cost of computation which seems to indicate an increased use of airflow simulation in the coming years. It is shown that velocity and temperature distribution can be predicted in small rooms of simple geometry as well as in large areas with a complicated geometry, such as theatres, atriums and covered shopping centres.

This paper describes a set of experiments conducted in a three bedroom house in order to identify the leakage distribution of the building and the air flow rate through the on-purpose designed opening of the interior doors. Starting from the depressurization test in every zone, we were unable to track all the flow equation of every specific identified connection. We therefore propose to characterize the leakage between two zones by a unique general connection. Its flow behavior (K,n) is determined by an optmization under constraints of the results of the various tests.

The distribution of wind pressure on a building envelope is governed by the size and shape of the structure and the turbulence characteristics of the wind. Observation of the mean wind pressures shows that surfaces are divided into pronounced zones of positive and negative pressure. The turbulence gives rise to fluctuating pressure components of appreciable magnitude. This fact changes the prerequisites of the ventilation for a given volume. The pressure in the cavity behind the facade materials depends on the external pressures over the facade.