Zoned temperature control in commercial buildings requires a means of regulating air from a building’s central HVAC system in response to the zone demands for heating and cooling. This can be accomplished in a number of ways, with the challenge to the design engineer being to find the optimum compromise between energy use, comfort and ventilation requirements and System flexibility.

While all systems have advantages and disadvantages, the primary disadvantage with dual-duct systems has traditionally been the complexity of the necessary control system and the lack of an affordable zone controller. The recent availability of affordable microprocessor-based controls, however, has changed this situation so that dual-duct systems can now be considered as a desirable alternative for effective zone control.

A dual-duct system with effective controls allows the consideration of a number of options not possible with other zone strategies. A communicating microprocessor-based system includes the option of off-site monitoring, remote maintenance monitoring and all the other benefits of a building management system. Additional benefits from effective dual-duct controls come from the possibilities of HVAC system design including hot deck change-over, load sharing and transfer, optimization of return air and economizer controls.

Units: Dual