The University of Chicago’s energy management program, recently recognized as an ENERGY STAR® Partner of the Year, is constantly looking for opportunities to increase energy efficiency on campus. However, in recent years the team has also placed an increased emphasis on water conservation and finding innovative ways to reduce campus water demand. One such opportunity was recently identified at the Ellen and Melvin Gordon Center for Integrative Science (GCIS), which houses laboratory and office space for both the Physical Sciences Division and the Biological Sciences Division. The building is among the University’s largest and most complex buildings; the majority of the building space is dedicated to research activities. 

Critical laboratory spaces require large volumes of airflow to replace air exhaust through fume hoods, remove any hazardous chemicals in the air, and maintain safe working conditions. This airflow must be maintained at all times throughout the year and cannot be recirculated; it must be pulled directly from outdoors. During winter this air is heated and humidified and in summer it is cooled and dehumidified, an energy-intensive process. However, reducing the humidity levels in summer also provides a unique and innovative opportunity for water conservation.

Each summer, the building’s cooling system dehumidifies the incoming laboratory makeup air and extracts over three million gallons of water through condensation. During peak conditions the system extracts 70 gallons per minute; this is equivalent to 35 showers operating at the same time! As is a standard design for these systems, all of the condensate was simply sent to the city sewer system. However, an extensive energy audit in 2019 identified an opportunity to recover the condensate and offset some of the building’s other water uses. The UChicago energy team pursued this recommendation and developed a system that would allow this water to be recovered and put to good use. The new condensate recovery system consists of small collection basins at each of the eight laboratory makeup air systems in the building basement. The water collected at these basins is pumped to larger tanks where it is then pumped up to the building’s cooling tower on the roof.

This system is able to recover all of the condensate during warm, humid weather and use it to offset the water demand of the building’s central cooling plant. As a result, this system reduces potable water use by nearly 3.3 million gallons per year. Put in perspective, that is enough water to fill the Myers-McLoraine Pool in the Ratner Athletic Center over four times. Refer to the figure below to see how the water savings compares to some other well-known systems.

The University of Chicago is a proud United States Environmental Protection Agency ENERGY STAR® Partner, collaborating with peer institutions to reduce higher education campus energy and water usage. The goal of this energy efficiency program is to: (1) reduce the impact on the environment as about 70 percent of University greenhouse gas emissions are from energy usage in campus buildings; (2) redirect funds currently going to utility providers back into the maintenance of our campus buildings; and (3) reduce the risk of disruption to our educational and research mission by locating and correcting issues before systems and components in our buildings fail. More than 300 energy efficiency measures have been completed in the University of Chicago campus buildings since 2009, and buildings will continue to be a primary target of our efforts to reduce greenhouse gas emissions and water use.