Nowadays it is rather common with demand controlled ventilation in public buildings and offices. The purpose of demand controlled ventilation is to adapt the ventilation to the varying needs of the occupations. In dwellings it is rather unusual with demand controlled system. The main reason for that is the high investment cost for the system. The outdoor air used for ventilation in dwellings is therefore not effectively used. For example in a mechanical exhaust ventilation system 50 % of outdoor air is leaving the house without being used of the people.

The installation of packaged heat recovery ventilation (HRV) systems has recently become common practise in new homes in Canada. Despite improvements in product quality and reliability, HRV systems are only capable of providing safe, continuous, efficient and effective ventilation if homeholders have a understanding of the basic operation and maintenance procedures and the system's interaction with other house systems. Furthermore, homeholders must be able to perceive the value of HRV systems if they are expected to operate them.

The C-2000 program for advances commercial buildings is an awards program to assist in the development of energy efficient and sustainable building technologies and design in Canada. The objectives of the C-2000 program are to develop energy efficient buildings using sustainable materials and technologies. The buildings must provide a high level of occupant comfort. The technology must be transferable to the current building industry and must meet market constraints.

So as to better understand and predict IAQ problems, the velocity field and distribution of local mean age of air were determined experimentally with three-dimensional anemometry and decaymode tracer gas measurements inside a classroom. We also performed 3-D numerical simulations of the velocity field in this room, using a CFD code. The time dependent concentration decay of tracer gas was simulated using the previously determined flow field in the pollutant transport equation. Relatively good agreement was found between the simulated and experimental concentration decay curves.

A laboratory, designed to form the basis for research aiming at increasing the knowledge concerning the interactions between indoor pollution sources and the indoor environment, has been taken into operation. One long term purpose of the activities in the laboratory is to develop theoretical models, based on experimental data, for the prediction of the air quality in real buildings. At present, the experiments focus on the relationship between the emission of pollutants from building materials and the environmental parameters, i.e.

A preliminary study of the potential for using central forced-air heating and cooling system modifications to control indoor air quality (IAQ) in residential buildings was performed. The main objective was to provide insight into the potential of three IAQ control options to mitigate residential IAQ problems, the pollutant sources the controls are most likely to impact, and the potential limitations of the controls. Another important objective was to identify key issues related to the use of multizone models to study residential IAQ and to identify areas for follow-up work.

By means of a case study involving a severe case of coupled heat and sir flow in buildings, this paper aims to quantify the differences resulting from different methods (ping-pong and onion approach) for linking heat and air flow models. The main conclusion is that when used improperly, the onion method will have implications in terms of computing resources, but - more seriously - the ping-pong method may generate substantial errors.

To achieve acceptable indoor air quality (IAQ), ASHRAE Standard 62-1989 recommends the use of the alternative IAQ procedure. The IAQ procedure can treat both constant-volume and variable-air-volume (VAV) with constant or proportional outside airflow rates. The relationships in Appendix E of the standard must be used in conjunction with the IAQ procedure to directly calculate indoor air contaminant concentrations in an occupied space.

A computer program has been developed to predict the wind pressure coefficients Cp on facades and roofs of block shaped buildings. The program is based on fits of measured data, including wind shielding by obstacles and terrain roughness. Main advantages of the program are: - it needs no expertise of its users on wind pressures; - the input is simple. It exists of building and obstacles coordinates and orientations; - generating Cp values for ventilation model calculations needs no separate action.

The ventilation of an attic is critical in estimating heating and cooling loads for buildings because the air temperature in the attic is highly sensitive to ventilation rate. In addition, attic ventilation is an important parameter for determining moisture accumulation in attic spaces that can lead to structural damage and reduced insulation effectiveness. Historically, attic venting has been a common method for controlling attic temperature and moisture, but there have been no calculation techniques available to determine attic ventilation rates.