English

Good indoor air quality in buildings becomes such a major concern that new design recommendations emerge in many countries (USA, Nordic Countries,...). Improvement of the interior environment should not beat the expense of higher energy consumption. Heat recovery systems are one appropriate answer to this challenge. However, additional energy savings could be achieved by applying demand controlled ventilation when the internal loads vary significantly. A CO2 controlled ventilation system has been installed in a conference room with high variable occupancy in mid 91.

Ventilation systems in dwellings should not only maintain the quality of the air, in other words limit pollutant concentration whatever the origin, but protect the structure, that is, limit condensation and the storage of excessive humidity in existing materials. Domestic ventilation represents a significant element of energy loss. It is a function that should be provided at minimum cost in terms of energy and therefore be directly dependent on fresh air requirements. Hence the introduction on the market af socalled hygro-adjustable ventilation systems.

This paper deals with the problem of the weather influence on ventilation rate for naturally ventilated buildings with purpose provided openings and vertical shafts. Hitherto, it has not been possible to predict the ventilation rate or to extrapolate it for other weather conditions than the measured ones, without performing a heavy calculation exercise by means of running a computer program. In the paper a prediction as well as an extrapolation procedure is outlined . The procedures are based on generalised output data from a single zone infiltration and ventilation model (AIDA).

This paper describes a method for measuring tbe dispersal of airborne contaminants by light-sheet illumination of aerosol tracen and digital image processing techniques. The goals of the research were twofold: to use field-portable and safe equipment to make near-instantaneous measurements of tracer aerosol concentrations over arbitrarily positioned two-dimensional planes of near-mom dimensions; and to carefully define similarity conditions under which aerosol dispersal can be considered an accurate surrogate for passive molecular dispersal.

The purpose of this study was to carry out a mathematical modelling analysis of the effect of indoor pollutant source strengths and ventilation rates on the concentration of pollutants. These concentrations are then compared to various human exposure limits and targets. The modelling was carried out for a variety of ages of residential detached housing for a range of Canadian climatic conditions. Although a literature search was performed, pollutant source strength data for housing was not generally available.

A cross-flow polymer membrane enthalpy exchanger has been designed which provides both heat recovery and moisture dissipation in the ventilation of living spaces. The exchanger is of benefit in providing fresh air during both cooling and heating seasons with minimum loss of energy. A prototype of the enthalpy exchanger has been constructed and tested. The air leakage of the equipment has been found to be negligible; that is, the two air streams are indeed non-mixing.

This paper reports the results of humidity and ventilation measurements in occupied residential buildings to study the effect of airborne moisture movement on condensation risks. The dwellings have been fitted with a cooker hood and an extractor fan (both with variable speed control) in the kitchen and an extractor fan in the bathroom.

This report presents the results from the registration throughout a month of relative humidity, temperature and outdoor air exchange as well as the concentration of carbon dioxide in each room of an inhabited single family house, in which all rooms are ventilated by a mechanical balanced ventilation system with variable air volume. The outdoor air rate is controlled by the relative humidity, which is kept on a value adequate to reduce the living conditions for house dust mites and prevent condensation on the indoor surfaces of the building.

Multi-zone models are a common tool for calculating air and contaminant exchange within rooms of a building and between building and outdoors. Usually a whole room is then modelled by one calculation node with the assumption of homogeneously mixed conditions within this room whereas in real cases 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.