Assessment of thermal environment in an atrium with air-conditioning

This article is a report on assessing the thermal environment in an atrium with air-conditioning by studying the air temperature at the occupied zone. By surveying the general shapes of the atrium buildings in Hong Kong, it is found that most of the atria have a glazed roof and a lower occupant zone cooled by installing air-conditioning systems. A three-zone model is proposed to study the air temperature in the atrium. The upper zone is hot due to solar radiation heating up the glazed roof, interior side walls and building contents; a middle zone is an intermittent region; and the lower zone is cooled by an air-conditioning system. Heat transfer between the zones through convection is proposed. Air temperature is predicted by solving the system of heat balance equations numerically. Further, a closed form expression on the air temperature at the lower zone is derived by assuming a constant upper layer temperature. The result is useful at the initial stage in designing thermal environmental control systems for atria.