Design and simulation of a hybrid ventilation system withearth-air heat exchanger

This paper describes the design and simulation of a hybrid ventilation system for a recently constructed circus building in Montreal. The HVAC system draws fresh air through two underground ducts which are used for preheating or precooling. Another feature of this building is that it uses displacement ventilation. The air is supplied at low velocities (about 0.2 m/s maximum) through large diffusers behind the top level seats or under the seats. The paper describes a numerical model for the two underground ducts and a CFD study for the HVAC system. Recent measured performance data agree well with predictions; during one of the initial shows in the summer of 2004, the underground ducts provided enough cooling (plus fresh air) to keep good comfort conditions with the theatre full and without the chiller operating.