A new model has been proposed for evaluating the discharge coefficient and flow angle at an inflow opening for cross-ventilation. This model is based on the fact that the cross-ventilation flow structure in the vicinity of an inflow opening creates dynamic similarity under the condition that the ratio of the cross-ventilation driving pressure to the dynamic pressure of cross flow at the opening is consistent. It was confirmed, from a wind tunnel experiment, that the proposed model can be applied regardless of wind direction and opening position.

The paper presents examples of hybrid ventilation and control strategies in office and educational buildings from the IEA ECBCS Annex 35 HybVent case studies. The purpose is to extract the lessons learned in the case studies about the control strategy used. The conclusions are that in each building project the control strategy has to be carefully designed and operated, not only in relation to the general building design and the ventilation systems in the building, but also in relation to occupants habits, reactions and expectations to indoor climate and comfort.

When do you know your ventilation ductwork needs cleaning, how do you go about it and what does hygienic mean? A new set of practical guides .. looks at addressing these issues.

More than three-fifths of the households in the U.S. heat or cool their homes with ducted forced air systems, so chances are good that air ducts are lurking within your walls, floors, or ceilings. These air ducts move conditioned air to warm and cool your family. They can be a great source of comfort-but more likely they are wasting energy and costing you money. Typical duct systems lose 25 to 40 percent of the heating or cooling energy put out by the central furnace, heat pump, or air conditioner.

Nosocomial infectior1s are a major problem in many hospital buildings, with ,approximately 10% of patients acquiring such an infection during a hospital stay. Airborne transmission is one of the important routes for a number of nosocomial pathogens. To combat this proq,lem there are a number of engineering control strategies, such as the use of ultraviolet germicidal irradiation and advanced ventilation techniques, which can be used. This paper outlines the 'state of the art' in air disinfection, and reviews recent research work in this field.

Ultraviolet light has been demonstrated to effectively de-activate pathogens and all other airborne bacteria, virus and mould species. The technology is already widely used within process users of air, GMP manufacturers and by those with an interest in a high quality indoor air supplies, such as call centres, banks and other high employee density locations. The technology is now being applied to reduce the incidence of nosocomial infection at healthcare providers worldwide.