In Sweden there are close to 500000 one-family houses heated by electric baseboard heaters. Of them 90 % were built before 1980. In this group the most common ventilation system is natural ventilation. Half of all houses 'with electric baseboard heaters were built between 1971 and 1980. The Swedish Council for Building Research has been asked by the Swedish government to carry out a program concerning the efficient use of electricity in buildings.
A 1: 20 scale model of a low-rise naturally ventilated building was tested in a wind tunnel. External pressure coefficients were determined for an open model with various combinations of ridge, sidewall and end wall openings, as well as for a sealed model. The pressure distribution is influenced by all structural modifications at various wind angles. The differences between the open and sealed models were pronounced especially at the ridge and the leeward sidewall.
Parking garages require ventilation because the exhaust fumes produced by the vehicles have to be discharged. This can be achieved with a mechanical or a natural ventilation system. A natural ventilation system has several important advantages compared with a mechanical system. As a rule natural ventilation systems arc simpler, cheaper and have fewer breakdowns, furthermore a natural system requires less maintenance and uses no energy (for air transfer).
One of the most important projects of the 1990s has just been completed - the naturally ventilated School of Engineering at De Montfort University in Leicester. Roderic Bunn reveals how it could influence a new breed of environmentally sensitive buildings.