The Jandel school in southern Sweden was thoroughly retrofitted in 1994-95. Both lighting and ventilation systems have been designed for high energy efficiency. New windows with excellent insulating performance have been installed. A before and after comparison shows that the energy required for heating has been reduced from about 210 k Wh/m2 to about 94 k Whlm2 a year, i.e. a reduction of about 55%. Electricity for building services systems has decreased by about 20%, despite the fact that considerably more computers are used in the school today than prior to rebuilding.

Grilningen primary school near Zurich, Switzerland, was built 20 years ago, and energy consumption, in particular for heating and lighting, was unnecessarily high. An unconventional retrofitting procedure involving new chip-wood furnace, interior insulation, mass-coupled ventilation and controlled artificial lighting was adopted. The work was carried out without interruption of normal school operation. The results are very promising and measurements indicate a drop in heat consumption of 70% with standards of comfort raised considerably.

The cost of higher insulation measures in all new house types may be paid for by savings from smaller, simpler and more efficient heating systems. These houses are more comfortable to live in, as well as up to 50% cheaper to heat.

Results from testing of a simple model in a wind tunnel are used to validate two computational fluid dynamics mathematical models. The results show that only the Reynolds-stress model provides a reasonably accurate representation of the inlemal flow, and that both models fail to predict the flow at the opening of the model

The paper describes a method to calculate the heat flow through a multiple layer wall in a natural climate. The thermal properties needed for the calculation are the thermal resistance and the heat capacity of each layer, and they are assumed to be independent of the temperature. The natural climate can be measured temperatures, either surface temperatures or temperatures of the surrounding air. The method is based on well-known equations for calculating the heat flow due to a sinusoidal temperature variation.