Energy Recovery Contributes to Savings in Award-Winning Buildings

Heat recovery is a key strategy in many lab energy performance improvement and decarbonization strategies, including projects that earned I2SL Sustainable Lab Awards last year: a major renovation of the National Institute of Standards and Technology (NIST) and a new construction project at Emory University in Atlanta. During a presentation at I2SL’s virtual Education Month in February, attendees learned about these two award-winning projects.

Dave Swanson of DLR and Adam Acree of Cator Ruma shared the energy-saving measures implemented during renovation of NIST Building 1, Wing 5 in Boulder, Colorado. Completed in 2023, the project modernized infrastructure of the 79,300-square-foot wing, including the engineering systems. Because the building is eligible for the National Register of Historic Places, changes to the original structure were limited. Air handlers were placed in the basement and exhaust fans are located on the roof. While this configuration and the project budget narrowed the team’s options, significant energy savings were achieved by installing a glycol runaround heat recovery system.

NIST has separate air handlers for lab and non-lab spaces; the runaround system uses piped fluid to allow heat transfer between the two airstreams without mixing them. In the winter, heat is extracted from exhaust air and used to preheat outside air as it enters the building. When the outside temperature is as low as 20 degrees below zero, this system can warm supply air by about 30 degrees before it moves on to the air handling unit for further heating. For cooling, the system works in reverse by rejecting heat from the outside air into the exhaust airstream. Combined with other measures, the renovated NIST wing earned a Labs2Zero Energy Score of 75 with a predicted 166 kBtu per square foot per year energy use intensity (EUI), equating to a 20 percent reduction from its baseline EUI.

Completed in 2023, Emory University’s new 350,000-square-foot Health Science Research Building II (HSRB II) conducted extensive energy modeling to identify energy-saving measures for the HSRB II offices, laboratories, vivarium space, and biosafety level three (BSL-3) containment labs. Each of the four areas’ air systems have dedicated exhaust units connected to an energy recovery system, which employs enthalpy recovery wheels and high-performance ductwork to reduce energy use. Drew Simpson of Vanderweil and Scott Rose of HOK described the LEED Gold-rated project, which has an EUI of 156 kBtu per square foot per year.

HSRB II is served by a 2,000-ton integrated chiller plant that includes high-efficiency, water-cooled centrifugal chillers and an energy recovery chiller that produces heated hot water by transferring heat from chilled water. In warmer months, the heat recovery chiller provides most of the hot water needed. During winter, exhaust air energy recovery coils maintain hot water production. To maximize run time and capacity of the energy recovery chiller, warm air can be transferred there from the exhaust system, rather than to the air handling units.

Read more about these award-winning projects. To learn more about energy recovery, read the I2SL Best Practices Guide: Energy Recovery in Laboratory Facilities.