English

A set of reporting guidelines has been established. The guidelines take into account the need for data concerning airflow within buildings and air exchange between a building and its surroundings. They also deal with issues such as pollutant production and transport, thermal properties and measurements of buildings and comfort related issues. The comprehensive nature of these guidelines should enable a large amount of data to be accrued in a form suitable for computer modelling and validation work.

The paper summarises the IEA, Executive Committee on Energy Conservation in Buildings and Community Systems, Annex 14 work on Condensation and Energy, a joint research effort of the Federal Republic of Germany, Italy, the United Kingdom, the Netherlands and Belgium, finished end of march 1990. First the complex relations between mould+ surface condensation, the outside climate, the building fabric, inhabitants behaviour and energy conservation are discussed. Then follows a short overview of the Annex achievements with mayor emphasis on the guidelines and practice results.

Demand controlled ventilation systems have recently become an interesting opportunity to achieve acceptable indoor air quality while minimizing energy consumption. Although they are usually designed for buildings showing relevant variations of occupancy (e g, office buildings, schools, etc.), there are now examples of applications also in residential buildings. One example is the passive humidity-controlled ventilation system recently developed in France. This type of installation has been tested in a five- storey apartment building located in Torino, Italy, during the winter 1989.

Turbulent flow fields of velocity and diffusion in several types of mechanically ventilated rooms are precisely analyzed both by model experiment and by numerical simulation based on the k-s two-equation turbulence model. The detailed analyses of contaminant diffusion by simulation make it possible to comprehend clearly the structures of velocity and diffusion fields in rooms. The flow fields in such rooms, as analyzed here, are mainly characterized by the inflow jet and the rising streams around it.

The ventilation system described here combines a central air shaft in the hall area with a mechanical waste air extraction system in the bathroom and in the kitchen. If there is a large amount of moisture in the dwelling, the volumetric flow of thewaste air fans is increased, the increase being controlled by means of hygrostats. This ventilation system ensures adequate ventilation of the dwelling. In dwellings without a supply air shaft, this hardly applies any more with the installation of windows with very low joint permeability.

As a consequence of measures required for reducing the heating energy consumption in residential buildings , there have been more and more complaints in the last few years on the appearance of mould in dwellings . In most cases, it is retrofitted or renovated old buildings which are affected [1]. Mould growth is frequently the result of a severe reduction in the natural air change rate in old buildings following the installation of airtight windows, while user habits remain the same as before.

Mechanical ventilation system performance involves the provision of adequate amounts of outdoor air, uniform distribution of ventilation air within the occupied space, and the maintenance of thermal comfort. Standardized measurement techniques exist to evaluate thermal comfort and air exchange rates in mechanically ventilated buildings; field techniques to evaluate air distribution or ventilation effectiveness are still being developed. This paper presents field measurements of air exchange rates and ventilation effectiveness in an officepibra-y building in Washington, DC.

Local and room mean ages of the air in a room may be measured by three versions of the tracer gas technique; which are the pulse method, the tracer step-up up method and the tracer decay method. The values of mean age obtained are of course subject to errors in the measurement of the tracer gas concentrations. The sensitivity of the three methods to errors in the tracer gas concentration is not the same, and in some cases can be very large. In order to examine this problem, test measuremenb have been carried out in a model room using the three difEerent methods.

Building regulations prevailing in France made it compulsory to use specific ventilation systems in new residential buildings since 1969. Different kind of ventilation systems (mechanically powered, temperature driven, hybrid systems,...) have been developed. This paper reviews these systems and outlines their advantages and drawbacks in single-family or multi-family buildings, with respect to architectural flexibility and comfort or safety requirements.

As part of the IEA Research Program Annex 18 "Demand Controlled Ventilating Systems" were tested in a one-family testhouse in relating to energy and ventilating specific aspects. The investigation should show whether demand controlled systems are useful in dwellings or not. Following items were checked: * Infiltration characteristics of the testhouse * Ventilation characteristics of different systems like temperature distribution, air movement, ventilating efficiency, air exchange and air quality.