In the last five years, increased competition in rooftop product offerings has led major manufacturers to incorporate new technologies designed to lower both installed and life-cycle costs. One application that is gaining much consideration for spaces with varying load and ventilation needs is demand-controlled ventilation (DCV). DCV is viable both as a new construction option and as a retrofit for existing spaces.
The building was originally equipped with a variable air volume (VAV) system, complete with direct digital control (DDC) of the VAV boxes, variable-frequency drives (VFDs), and staged compressors on the rooftop unit. With the existing DDC system, he was able to call up the system on his computer, monitor control parameters at his discretion, and make changes to building set points and box settings.