The material presented in this paper highlights some aspects of""two research projects, The control of natural ventilation , and Night cooling strategies . The research has led to the development of generic control strategies. These have evolved from consideration of the control strategies used in naturally ventilated buildings utilising Building Management Systems (BMS) control together with experience obtained from monitoring three naturally ventilated buildings. The site monitoring has also led to recommendations being provided for commissioning and fine tuning procedures.

With effect from January 1st, 1995 the amended Heat Transfer Barrier Act (,,Warmeschutzverordnung ) was introduced in the Federal Republic of Germany, replacing the 1982 version. This decree is binding on all houses to be built so that they reach the low energy standard. Former decrees envisaged mainly the reduction of the transmission heat loss while the amended version takes into account all other relevant aspects such as internal and solar heat gains as well as ventilation heat losses, and includes them into an energy balance procedure.

Especially in modern buildings with small capacity of humidity storage it is necessary to reduce the humidity in the supply air. Normally a refrigeration system containing CFC s is used. There are some alternative fluids available, but mostly they show a high global warming potential. These systems all need electrical energy to be driven and therefore it is necessary to consider other possibilities with alternative systems. The most promising systems are sorptive systems which are used in open cycles.

A breakthrough in ventilation research was made once it was realized that ventilation principles based on mixed flow patterns are not optimal and that further energy savings can be achieved if an alternative technique could be developed. Several researchers, particularly in the Nordic countries, have shown by theoretical studies that replacing mixed ventilation flow by displacement flow increases ventilation efficiency. This also results in decreased air supply volumes and thus decreased energy requirements. In addition, lower air velocities may reduce problems of comfort and noise.

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.