We describe the use of constant injection and pulse injection techniques for measurement of airflow in a duct. Tracer-gas measurements were compared with measurements made using a pitot tube and a hot-wire anemometer. Tracer-gas concentration, air velocity and pressure distribution were measured at various distances from the duct wall and inlet. An empirical equation was obtained for the entrance length required to achieve fully-developed turbulent flow and this was compared with measurements made using a pitot tube and hot-wire anemometer.

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.

Kitchen hoods are frequently found in Belgian kitchens. Most of them have as only function intensive ventilation during certain cooking activities. It is expected that kitchen hoods with appropriate performances can also play an important role as devices for guaranteeing basic ventilation. The aims of the research can be summarized as follows: How do occupants evaluate the performance of existing kitchen hoods? What are the sound levels (dB(A)) in various locations in these dwellings due to the kitchen hood?

A test room with a Displacement Ventilation System was built. Temperature control was provided with a DDC (Direct Digital Control) System, controlling the air volume and the air inlet temperature. Air velocity and temperature profiles were measured at different locations in the room for various internal loads. The aim of the control was not only to provide a constant temperature but also comfortable conditions. the temperature gradient, the air velocity and the radiant heat exchange were taken into consideration for the comfort condition in the space.

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.

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.

The performance of a system for demand-controlled ventilation was investigated for a period of 1.5 years. Presence sensors of the passive infrared type are used to control the ventilation rate in each classroom. The signal from the presence sensors was recorded, as well as the CO2 concentration in the classrooms. One of the classrooms was equipped with displacement ventilation. A comparison was made between displacement and mixing ventilation to investigate the CO2 concentration in the stay zone.

Field investigations were undertaken on five houses to determine the potential for improved performance and lower costs through the use of a demand controlled ventilation (DCV) systems. All 5 houses were energy efficient, low toxicity construction, and were chosen to reflect a range of mechanical systems consistent with Canada's new ventilation standard (CSA F326). Three of the test houses were extensively monitored and, after 90 days of conventional operation, were converted to DCV using a wide variety of sensors and controls.

A literature search was performed to gain as much knowledge as was available on ventilation, indoor air quality sensors and demand controlled ventilation (DCV) strategies. Field data was gathered on the time and spatial variation of indoor air quality in houses. Appropriate designs were then developed. Design strategies are discussed elsewhere (1). Hour by hour simulations of the performance of several ventilation systems in various Canadian climates were done. Energy savings were then estimated for DCV and heat recovery ventilation with air to air heatexchange.

This paper evaluates the suitability of humidity-controlled house ventilation system to determine (i) the effectiveness of relative humidity as a sensing element, and (ii) the operating and performance characteristics of such ventilation strategy. The ventilation system consists of continuously running "mechanical" air extractor units and "passive" air inlet units equipped with humidity sensors. The ventilation system was installed in two single storey houses which were monitored during November 1989 to April 1990.