Wilmette Public Library
Wilmette Public Library is a 66,000 square foot facility

Business Challenge
Variable air volume (VAV) boxes operated by defective electronic control components were causing comfort and control problems. This resulted in uneven heating and cooling as well as escalating repair costs.

The Air Comfort Solution
Air Comfort recommended a temperature control upgrade using Direct Digital Controls (DDC). Because the work being done benefited everyone involved, Air Comfort shared the cost involved in retrofitting the initial VAV box. DDC control systems are easily expanded, so Air Comfort set off retrofitting the most problematic of the VAV boxes. A second phase of work soon followed, which involved replacing the remaining VAV box controllers.

After the success of the first and second phases, the library board decided to continue upgrading their HVAC systems. The third phase included complete control retrofit of the rooftop VAV air handling units (AHU) along with control of boilers, heat exchangers, and pumps. Air Comfort also installed variable frequency drives (VFD) on the AHUs to replace damper actuated air volume controls. In the fourth phase, Air Comfort added another boiler room, multi-zone air handling unit and constant volume air handling units to the control system.

The Result
By coupling DDC control strategies, frequency drives, and improved operator access, the library benefited through not only increased comfort levels, but energy savings and ease of operation as well. “The fans run much quieter and more efficiently. The operation of all components can be viewed at the new Operator PC Workstation. This saves our staff time and really helps in pinpointing problems,” according to Molly Brown, administrative assistant. Wilmette Public Library employees and visitors are now experiencing a more comfortable and pleasant environment.