A breath of fresh air

An innovative air-conditioning system could improve air quality and energy efficiency in the home, its UK developer claims.

An innovative air-conditioning system could improve air quality and energy efficiency in the home, its UK developer claims.

Designed at Cambridge University’s Martin Centre for Architectural and Urban Studies, the Dwell-Vent system combines two tried-and-tested technologies: ‘passive stack ventilation’ and ‘supply air’ windows to replace stale air from inside the home with warm fresh air from outside.

Passive stacks are metal tubes typically installed in kitchens and bathrooms that remove warm and humid air by allowing it to rise up through a vent in the roof. This removes condensation but wastes heat.

Supply air windows are similar to double glazing except that the gap between the panes is used as a route for air to enter the building. The gap also helps warm the air before it is released back into the room. The system’s developers estimate that Dwell-Vent could reduce heating costs in an average home by 15–20 per cent.

Smart vents at the top of the windows are key to the system. ‘These regulate the airflow between the two panes and make sure the air is kept at a constant speed so we get completely smooth, laminar airflow which provides an excellent barrier between the pane and the outer pane. It is regulating the airflow that gives us such amazing insulation values,’ said one of its developers, Dr Michael McEvoy.

Any heat that escapes from the room through the inner pane gets caught between the two panes and ends up being delivered back into the room. The windows are also fitted with a non-return valve so that the air only runs in one direction. The system is also designed to improve the air quality as well as provide heating.

McEvoy said: ‘Unlike normal windows which let dust, pollen and air pollution into the room, this system filters some of these elements out of the air, creating a cleaner environment.’

Trials have already taken place in Denmark, Ireland, Poland and in Norwich where the Carbon Trust has provided funding. Trials in retrofitting the system to older homes are also currently underway in London.