Four Passivent Aircool window ventilators have been installed as part of the £1m upgrade of Hornchurch library in east London
Integrated into the new glazed facade of the sixties building, the ventilators provide a constant, draught-free flow of fresh air, while the warm, used air rises and is extracted from Passivent Airstract terminals on the roof.
The system uses the natural air-movement principles of convection (warm air rising) and the venturi effect (wind passing over the terminals causing suction) to work day and night.
It can ventilate twice the depth of the building that single-sided ventilation strategies can. It also provides night cooling, as internal and external temperatures have a higher variance at night, so there is increasing convection. By employing natural air movement, the system uses minimal energy and operates silently.
As well as a significant reduction in carbon dioxide emissions, Passivent claims its natural ventilation systems reduce energy consumption by up to 50%, compared with air-conditioned buildings, and offer 75% savings on maintenance costs.