Northwestern University, Norris Aquatics Center

Evanston, IL

NU, Crown Sports Pavilion and Norris Aquatics Center, exterior


GBA replaced two air-handling units serving the natatorium as well as indoor direct-expansion condensing units for the 95,000-square-foot aquatic center on the university’s Evanston campus.


ASHRAE Region VI, Technology Award First Place (Educational Facilities, Existing) , 2011

ASHRAE Illinois, Excellence in Engineering Award, 2010

HVAC and Chiller Replacement, Engineering Design

The two existing air-handling units (AHUs) serving Norris Aquatics Center were more than 25 years old, and neither incorporated an economizer mode. This scenario presented an opportunity for energy savings. In addition, the pool water heating energy recovery portion of the existing AHUs did not function properly, causing easily recovered energy to be discharged from the building.

  • Two new custom AHUs and a modular chiller plant replaced the two existing 25,000-cfm AHUs and four existing 20-ton indoor direct-expansion condensing units.
  • The AHUs were selected with low-velocity coils and filters (400 to 450 fpm), reducing pressure loss across the coils and filters and resulting in lower fan power draw (compared with a typical 500-fpm fan velocity AHU). The two 40-hp supply fans and two 15-hp return fans were equipped with premium-efficiency motors rather than standard-efficiency motors.
  • The condenser water system was used to capture waste heat from the chilled water system.
  • Economizer modes were added to the AHUs, providing significant energy savings over the previous systems.
  • All new equipment includes direct digital controllers that are tied into the campus energy management system for remote monitoring and control. This allows for more effective trending of operating parameters for better management.
  • The project has an anticipated annual energy savings of more than $90,000.

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