English

In Halmstad a multi-apartment house has been built with air carried heating. Fresh air was used as the only heat carrier. To improve the air quality it was decided not to use circulation flow, which is normally required for air carried heating. Theheating requirement was obtained with a higher air flow than what the standard requires. This also implied improved air quality. The standard specification states 0.5 changes per hour as the minimum requirement, but in Halmstad the house was ventilated with 0.7 - 1.0 changes per hour.

Within the frame of the IEA Annex 20, laboratory and numerical experiments were conducted in order to study the flow within an isothermal parallepipedic testroom (L x W x H = 4.2 m x 3.6 m x 2.5 m). The air is injected through a complex diffuser (made of 84 nozzles) near the ceiling and is evacuated through a rectangular exit just below the inlet. While other participants to the Annex 20 made measurements on aeraulic testrooms, we used a hydraulic model scaled to the sixth. The parameters were determined according to a Reynolds similitude.

Modern one-family houses in Scandinavia are often ventilated by an exhaust fan. Most of the outdoor air probably enters through whatever cracks and openings there are and only a small part enters through the supply vents in many of these houses. The overall supply of outdoor air might be adequate, but some rooms often do not get enough of outdoor air. The constant concentration tracer gas technique was used to examine the supply of outdoor air. Fan pressurization combined with infrared photography were employed to characterize the air leakage of the building.

The use of indoor carbon dioxide levels is a good method for controlling indoor air quality in office buildings. The measured CO2 is used to determine the amount of outdoor air needed to purge air contaminants and to obtain the desired CO2 indoors. Two floors of a commercial building in Montreal were used in the study.

A laboratory investigation has been made in a modern Swedish bathroom continuously ventilated by an exhaust fan. The tests consisted of measurements of the humidity, temperature and local mean-age after a standard shower. The measurements were mainly made in a non-heated installation.

Tracergases provide a way to determine airflows in different situations. In some cases it is the only way to get quantitative information. This paper presents two cases in which tracergases are used for measuring the internal leakage in heat recovery units. Internal leakage in heat recovery ventilators (HRV's) for domestic use may cause some problems: - the real quantity of fresh air entering the building is unknown - electrical power for the fans is used inefficiently - smelling air a.g.

The measurements reported in this paper were carried out in a mock up of an office room, ventilated by a commercial supply air terminal consisting of 84 nozzles (characteristic dimension SqRoot of As = 0.0975 m). The test room configuration was identical to the one used within the IEA Annex 20 work. Results from isothermal supply is reported. A constant-temperature hot-film anemometer with fast dynamic response was used torecord the instantaneous velocities.

Increasing interest is attributed to the problem of the accumulation of organic vapours emitted from indoor building materials due to an effective insulation of buildings with low ventilation rates. A measurement technique for determining emission rates using a 1 m3 laminar flow test chamber is described.

This paper describes the application of numerical models to predict the ventilation rate and internal air movement patterns for a naturally ventilated industrial building and compares the results with measured data. Two modelling techniques have been employed. Firstly, a zonal network model (HTBVent), using leakage area data derived from fan pressurisation measurements, was used to predict the time varying ventilation rate in response to variations in wind velocity and internal-external air temperature difference.

The methods available for the measurement of air infiltration and air movement in large industrial halls are restricted by the size of the building and the nature of the operations which take place within it. Single tracer decay measurements are the easiest to perform and this paper examines the possibility of extracting useful information from them. Using a multi-zone representation of the building volume, the properties of tracer decay curves are considered, and the ease of extraction infiltration and air flow data examined by means of simulations.