University of Maryland Hornbake Library

Advanced Humidification Air Handler Replacement

Contract Value: $1,894,000
Contract Type: Engineered Design

Project Date: August 2007
Compeletion Date: June 2009

ACI was contracted by the University of Maryland through technical bid selection to replace two existing Carrier outside air make-up units equipped with heating coils, cooling coils and steam humidifiers that directly inject main plant steam into the existing ductwork. ACI demolished the existing AHUs and installed two new Munters AHUs equipped with pre-cool coils, pre-heat coils, post-cool coils, a Dri- Steem humidifier and a desiccant wheel for dehumidification as well as a bank of dust free 95% carbon filters. Each unit was designed to supply over 10,000-cfm of pre-conditioned outside air to the existing AHUs for ±1-degree dew point control. Each unit is equipped with a Siemens PLC which ACI subcontracted with Capron Company Inc. integrated through Modbus with the existing building BMS. A number of ancillary equipment items were installed to support the new AHUs.

ACI installed one complete Reverse Osmosis (RO) water treatment system to supply purified water to the two Cemline unfired steam generators that produce steam at 5-psi for the two new Dri-Steem humidifiers. During planned building chilled water outage ACI moved one Bell & Gossett chilled water pump and ABB VFD to make room for the new AHU and installed a second redundant Bell & Gossett chilled water pump and ABB VFD.

Special Provisions: Continuous operation of at least one AHU required for building pressure control. Hornbake Library is the location of many of priceless historic documents and artifacts from a wide variety of collections. This educational facility was continuously occupied throughout the project.