Until the late 1950s, virtually no firms specialized exclusively in testing, adjusting, and balancing the components of heating, ventilating, and air-conditioning (HVAC) systems. The balancing, if performed at all, was done by the HVAC contractor, who lacked the necessary expertise required for advanced testing and balancing. After installation, many design engineers found that their systems were not working, not because of flawed design but because of improper balancing or deficient performance of the equipment.

The paper is concerned with the procedure for regulating or balancing a ventilation· system, so as to ensure that each outlet supplies or extracts its proper quantity. It deals with methods, organisation instrumentation and recording of results; it also discusses the accuracy required and attainable in ordinary practice. The advocated method of regulating consists of balancing the proportions of air flow at the junctions of a system, dealt with in a routine order, followed by the adjustment of the complete system to design volume by a final setting at the fan.

Ventilation design has a long history in China. The ancient pioneers used engineering skills to change the indoor environment. In this review, basic natural ventilation design ideas are introduced from both a historical and modern viewpoint. Attention is paid to new natural ventilation system developments, such as the design and testing of natural ventilation inlets and outlets for the stack and solar chimneys. Theoretical aspects of ventilation design are also considered. Today, the use of mechanical ventilation systems in China is growing for both domestic and non-domestic buildings.

This paper reviews the results from a field survey of thermal comfort within two types of buildings; old (traditional) and new (contemporary), in Ghadames oasis in Libya. The survey was undertaken in the summer seasons 1997 and 1998, which were typical of the hot-dry climate of North Africa. It shows how the 237 residents responded to the environmental conditions. Questionnaires were collected from the residents of 51 buildings: 24 old buildings that employ natural ventilation systems with courtyards and 27 new buildings that employ air-conditioning systems.

Seven years after the groundbreaking Queen's Building, ventilation towers are back on the campus agenda with this passive solar library for Coventry University. How has the design moved forward?

Covers low energy cooling technologies, the numerical design tools, and case study buildings.