Design Solution · HVAC & Energy
Design Solution · Dream about it
Central air modulated per zone via VAV boxes.
A central air system modulates supply volume to each zone through VAV boxes with CO2 and temperature control, giving great load capacity and comfort. It needs plant-room space and careful air balancing, and is well suited to deep floors with variable occupancy.
A VAV system uses a central air-handling unit to supply conditioned air to the floor plate and modulates the volume delivered to each zone through terminal boxes controlled by CO2 and temperature sensors, handling both the cooling and ventilation load through a single all-air distribution network. The system performs well at the building scale — central plant can be sized and operated efficiently across diverse loads, and the all-air distribution suits high-occupancy, high-ventilation-rate spaces such as open-plan offices and trading floors. The constraints are physical and operational: a VAV distribution needs significantly more ceiling void than a chilled beam or FCU system, typically 500–700 mm for primary and secondary ducts on a deep floor plate, and the plant room volume for the central AHU is substantial. Balancing the system after installation and rebalancing it when occupancy patterns change require specialist commissioning. No deployment evidence is on record, though VAV is a mature commercial system with a published performance and cost base; a specifier considering it primarily needs to verify that the available ceiling void and plant room space can accommodate the distribution before committing to the approach in design.
#VAV #air system #demand control