Walworth Academy opened in 2007 and moved into its new building in January 2010, uniting the whole school on a single site for the first time. The academy serves 180 in six classes students each year and opened a sixth form in September 2010, so that Walworth students can continue their studies to age 18.

A key resource of the new 1,200m² building is a double height multi-use school hall / auditorium and a full size sports hall. The latter, together with other facilities, provides an excellent resource for the local community as well as for Walworth students who, besides using the hall for physical exercise also use it for mental exercise when sitting school examinations.

Ventilation elsewhere in the academy is achieved with cross ventilation using opening windows. However, for the hall, which is designed for an occupancy level of 270 people, cross ventilation was not considered practical. Gifford, the engineering consultants on the new build project therefore adopted a Monodraught natural ventilation strategy featuring six 1,200mm circular windcatcher natural ventilation systems.

Monodraught windcatchers are based on an innovative technology that can eliminate the need for air conditioning and in turn reduce the carbon emissions produced by burning fossil fuels. They are widely recognised as the most effective means of harnessing the wind’s potential as a renewable energy source by using wind pressure to cleanse and ventilate areas within buildings. They are used extensively to provide natural ventilation in areas where cross ventilation and single-sided ventilation are not practical or as effective.

Roof mounted and designed to operate with virtually no moving parts, windcatchers use established atmospheric principles and the natural effects of the wind to bring fresh air into a building and extract stale warm air, using only natural forces. Dampers can precisely control airflow through windcatchers dependent on the internal temperature and CO2 levels, and at night can be programmed to open fully, providing a downwash of cool air that leaves interiors feeling fresh and clean for the following morning, reducing energy costs and the academy’s carbon footprint.

The windcatchers in the sports hall are fitted with motorised volume control dampers, linked to a Monodraught iNVent intelligent natural ventilation control system, which uses sensors to monitor the temperature and CO2 levels in the hall at all times. The natural ventilation strategy is also integrated with the hall’s high level radiant heating and the school’s building management system.

Commenting for Gifford, director Philip Kite says: “We have used windcatcher natural ventilation systems on a number of projects. We know they work well in sports halls and provide a very cost-effective solution.”