Project Information:

This project is for the advance planning and design of a replacement HVAC system as explained in the following description. The design fee is 9% of the total estimated project cost of $5,679,567.

The building is continuously conditioned four 20-year old constant volume reheat HVAC systems on each floor. Each system includes wrapped ductwork and a constant-volume draw-through AHU that includes a CHW coil with open condensate pan, a SA fan, and direct steam injection humidifier in the SA trunk. A steam preheat coil has been provided in the common OA plenum at the AHUs on the lower floors to ensure against CHW coil freeze-ups, as exhaust energy recovery systems are not present to precondition ventilation air, and such coils are planned for the upper floors. The AHU framing and CHW coils are showing signs of corrosion, while evidence of microbial growth was observed inside of the AHUs, downstream of the CHW coil in open condensate pans and on the fan plenum liner. The liner should be removed, and the units should be externally insulated. These AHUs should be replaced within the next five years with VAV models, and glycol energy recovery coils should be provided in the common OA plenum to precondition ventilation air with energy exchanged with exhaust (as described below).

The two makeup air H&V systems deliver roughly 23,000-CFM of filtered OA to individual lab hoods, and each consists of wrapped supply air (SA) ductwork, and a constant volume, draw-through AHU in the attic. An energy recovery coil and a VFD is recommended for each H&V unit to accommodate the proposed exhaust system improvements described below.

There are roughly 30 separate, continuously operating exhaust fans in the attic that discharge through the roof, serving individual lab hoods and general exhaust systems. These exhaust fans should be replaced within the next ten years with a centrally manifolded system of variable speed fans and associated glycol energy recovery coils to precondition ventilation air at the AHUs. Individual lab exhaust systems would also be fitted with digitally controlled VAV dampers, interconnected with proposed VAV-reheat boxes (described above).

MacNider Hall

Project Related Sites:

Project Location Map
University Plan Room Information
Campus Building Design Standards