Thermal Performance of an Atrium with Hybrid Ventilation and cooled air supply

Abstract

A reduced-scale model of an atrium with displacement ventilation and natural exhaust in the ceiling was applied in experimental investigation, where its air velocity field was measured by particle image velocimetry (PIV). By computational fluid dynamics (CFD) method, the indoor airflow in both the reduced-scale and real-size atrium model with hybrid ventilation under cooling conditions was simulated. The experimental and calculated results show that the hybrid ventilation that coupled natural exhaust with mechanical air supply of air conditioning can satisfy the thermal environments requirements. Moreover, with the same heat gain and supply air parameters, space cooling load of the atrium can be a little less when applying displacement ventilation. In addition, the vertical temperature gradient in the atrium, the cooling load of handling return air and the temperature difference between supply and exhaust air decrease with the increase of exhaust air rate. An optimal exhaust-supply air ratio for the minimum cooling load of the air conditioning system in the atrium was obtained under a given heat gain and fresh air parameters.