WREC 1996 AIR MOVEMENT IN NA TlTRALLY -VENTILATED BUILDINGS H.B. Awbi Department of Construction Management & Engineering The University of Reading Reading RG6 6AW, UK ABSTRACT The air movement and the distribution of CO 2 in naturally ventilated office room and an atrium is investigated using computational fluid dynamics. The results show that natural ventilation is capable of achieving acceptable CO 2 levels. Adequate comfort levels could also be achieved for a typical UK summer climate in both types of buildings. Both wind-driven and buoyancy-driven flows are considered. KEYWORDS Natural ventilation; room aIr movement; CFD; cross-ventilation; single-sided ventilation. INTRODUCTION Natural ventilation is now considered to be one of the requirements for a low energy building design. Until about three decades ago the majority of office buildings in the UK were naturally ventilated. With the availability of inexpensive fossil energy and the tendency to provide better indoor environmental control, there has been a vast increase in the use of air-conditioning in new and refurbished buildings. However, recent scientific evidence on the impact of refrigerants and air-conditioning systems on the environment has prompted the more conscious building designers to give serious considerations to natural ventilation in non-domestic buildings. The design considerations which ought to be considered in naturally ventilated buildings have been discussed in a previous paper, Awbi (1994). Two major difficulties that a designer has to resolve are the questions of air-flow control and room air movement in the space. In mechanically ventilated spaces, there are well established techniques for assessing the air movement that a system is expected to produce, Awbi (1991). Because of the problem of scaling and the difficulty of representing natural ventilation in a laboratory, most of the methods used for predicting the air movement in 241