University of Georgia
April 2015
Cooling the campus

Tom Lawrence stands in front of the chiller located in the Driftmier Engineering Center. He and other researchers are looking at how UGA's District Energy Plant 1—a system of chilled water loops that provide air conditioning to much of central campus—can be even more energy efficient. (Credit: Mike Wooten/UGA)

Cooling the campus

UGA collaboration finds energy-efficient solution to hot problem.

Stories about creating a more sustainable world often begin in exotic places like the Amazon rainforest or the polar ice caps. This story begins near the intersection of Baxter and Hull Streets in Athens, at the University Georgia’s District Energy Plant 1.

District Energy Plant 1, or DEP1, is the heart of a chilled water loop that provides air conditioning to much of UGA’s central campus, including the Richard B. Russell Building Special Collections Libraries, Miller Learning Center, Bolton Dining Commons and the Tate Student Center. DEP1 and six other loops cool much of campus through a system of underground piping that connects buildings and their associated chillers.

Chilled water loops are an efficient method of cooling, allowing several large buildings to “share” equipment and the energy needed for their operation. DEP1 came online in 2010, and the UGA Office of Sustainability estimates it reduces energy consumption by approximately 25 percent in each building connected to its chilled water network. Now, a team of researchers believes the energy plant may present additional opportunities for UGA to create a more sustainable campus.

“The main goal is to reduce peak electrical demand on campus,” said team leader Tom Lawrence, a faculty member in the College of Engineering and coordinator of the mechanical engineering program. “These large air conditioning systems and the energy they consume present an enormous opportunity to reduce our energy consumption at key times. This reduces UGA’s environmental footprint while saving money at the same time, a win-win.”

The two 1,000-ton water chillers in DEP1 consume approximately 1.2 megawatts of electric power when both units are operating at their peak, according to Lawrence. That’s about the same peak demand as generated by 300-400 residential air conditioning systems.

To maximize the efficiency of DEP1’s chilled water loop, the team plans to build and test aspects of a model predictive control system. The system will analyze a variety of recent historical and projected data and provide campus facility managers with a game plan for controlling cooling systems on a given day. The team’s work is funded by a series of research grants from the Georgia Power Co.

“We want the model to consider usage patterns, building occupancy, projected periods of peak electrical demand, recent and current weather conditions as well as the forecast for the next few days,” Lawrence said. “Using that information, we can predict what our electricity cost will be. The campus could then optimize cooling and building system operations based on those projections.”

The bottom line: UGA would be able to reduce its consumption of electricity at peak intervals when the cost is highest.

“We believe this model offers the potential to save several hundred dollars per day in electricity cost during a typical summer day of operation,” Lawrence said.

As with many research projects in the UGA College of Engineering, Lawrence’s work is distinguished by its multi-disciplinary approach and the inclusion of undergraduate students on the research team.

The team includes two faculty members from the department of management information systems in UGA’s Terry College of Business: Rick Watson, the J. Rex Fuqua Distinguished Professor; and Maric Boudreau, associate professor and head of the MIS department. Other team members are Kyle Johnsen, assistant professor of computer systems engineering in the College of Engineering, and Jason Perry, a program manager in the UGA Office of Sustainability.

Undergraduate student researchers Jordan Coleman, an environmental engineering major, and Michael Karsten, a mechanical engineering major, round out the team. Two graduate students—at the master’s and doctoral levels—will join the group later in this year.

A longer-term goal of the project is to integrate solar and wind energy into the equation, Lawrence said. By analyzing weather forecasts and other data, the model could help UGA optimize potential energy available to the campus power grid from these renewable sources.

— Mike Wooten, College of Engineering