Mechanical ventilation systems have been adopted in airtight energy- efficient houses in Canada to provide fresh air, remove moisture and indoor pollutants and provide a comfortable environment for the home-occupants. Homes constructed under the R-2000 Home Program are equipped with mechanical ventilation with heat recovery. Since 1984, the performance of approximately 700 R-2000 Homes has been monitored on an annual basis. This monitoring has included the measurement of indoor levels of formaldehyde and the documentation of ventilation system operation.

Infiltration heat losses due to heating appliances located within the living space are normally evaluated by reducing the conversion efficiency of the boiler, with no consideration for the fluid dynamic interaction between boiler, chimney and building. Purpose of this work is to develop a simplified mathematical model of the overall (building + boiler + chimney) system, suitable to calculate the pressure distribution and air flow rate in the building induced by the simultaneous effect of natural forces and the exhaust system.

Air leakage through the building envelope is of great importance for the energy use of a building. However, from an indoor air quality standpoint, the size of interior leaks in e.g. multifamily buildings could be important as e.g. a source of pollution. Using the standardised Fan Pressurization test method, it is not possible to separate interior leaks from leaks in the building envelope. One way to separate these leaks is to simultaneously depressurise (or pressurise) adjacent apartments to the same pressure and thereby eliminating interior leakage.

The specific value of different flows resulting from air exchanges between rooms or with the outside is not always important. An extensive model is not suitable when only estimations or tendencies have to be drawn (very time consuming). So we developed a simplified infiltration model for predicting airflows in single rooms and between different zones of a building. We integrated this model into a building transient thermal simulation program set up to a micro-computer system. So as to obtain this model, we used simplified assumptions.

This paper describes a two-dimensional numerical study, by finite-volume method of buoyancy-driven flow in a half-scale model of a stairwell. The stairwell forms a closed system within which the circulation of air is maintained by the supply of heat in the lower floor. The heat loss takes place from the stairwell walls. The mathematical model consists of the governing equations of mass, energy, momentum and those of the k - E model of turbulence. The predicted flow pattern and the velocity in the stairway are presented and compared with the authors' experimental data.

An element-assembly formulation of multi-zone contaminant dispersal analysis theory is described. In this approach a flow system is idealized as an assemblage of mass transport elements that model specific instances of contaminant mass transport in the flow system. Equations governing the mass transport phenomena modeled by each element are expressed in terms of contaminant concentration variables, the nodal concentration variables, that approximate the contaminant concentration at discrete points, the system nodes, in the flow system.

Since thermal comfort on human body is influenced by the local air flow speed, it is needed to estimate the distribution of air flow speed in a room for the "effective ventilation". Numerical solution of the equations for the motion of 3-dimensional turbulent air flow and model experiments are conducted for this purpose. The experiment model is a single room model house with 2 windows on the opposite walls. It is actually ventilated by the natural wind. Non-directivity thermistor anemometers are used to measured the 3-dimensional distribution of indoor air flow speed.

A constant concentration tracer gas (CCTG) measuring system needs a control algorithm to calculate, at each sampling time, the required tracer gas injection rate to keep the gas concentration at a target level. A new control algorithm is presented here in full detail. Practical considerations concerning modifications to take into account the physical limitations of the CCTG system and the computing of the optimal control parameters are also presented.

This work is concerned with measuring air flows between the floors of houses. A simple measuring technique is described in which two portable SF6 systems were employed. The design and construction of the portable system are presented. A comparison of air flow patterns in a superinsulated house and a standard house is made. Results showed that the air flow between the upper and lower floors of the superinsulated house was about 20 m3/h compared with 100 m3/h in the traditionally built house.

Increases in building air tightness for purposes of energy saving have, unfortunately, also led to a significant increase in the number of instances of condensation damage, particularly in domestic properties. The cost effective control of condensation is a large problem in the United Kingdom, especially for local authorities with large housing stocks.