The University of Pittsburgh and more than 100 other organizations across the city are reducing their carbon emissions and water usage as part of the Pittsburgh 2030 District, a larger nationwide effort.
Green Building Alliance, which manages the district of over 1,000 buildings, recently released its 2024 progress report. The report highlighted energy efficiency and resiliency projects completed during the past two years, including the University of Pittsburgh’s Central Utility Building.
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GBA reported partners met their goal of reducing carbon emissions by 50 percent from the baseline recorded in the 2003 Commercial Building Energy Consumption Survey.
“The fact that we met the first milestone in our challenge goals six years early is really exciting,” said Ashley DiGregorio, Pittsburgh 2030 District senior director.
DiGregorio said this was made possible because of GBA’s work with partners to assess the usage of utilities and provide recommendations for increasing efficiency.
“After they’ve already reduced what they need to consume, they’re buying more renewable energy, or in the case of someone like Pitt, they are generating renewable energy with something like a solar array,” DiGregorio said.
Pitt’s Central Utility Building
According to DiGregorio, Pitt’s Central Utility Building serves as a leading example of energy efficiency and water reuse in the 2030 District.
“We have people from all over Pennsylvania and further come to see how they can apply the same kind of model to operating their hospitals in other areas, other college campuses, large government campuses,” DiGregorio said.
The building is a three-story chilled water plant with an electrical substation located on the upper campus. The facility provides chilled water for buildings and research equipment. It was constructed in 2023 to tie into the existing chilled water network and support projects such as a new arena and sports performance center, which is currently under construction.
Unlike the existing plants, the Central Utility Building is attached to a 250,000-gallon cistern that lies underneath the adjacent parking lot. It collects rainwater from the rooftops of buildings on upper campus and wastewater from the nearby Carillo Steam Plant for reuse.
Vice Chancellor of Facilities Management Scott Bernotas called the water recovery system a win-win-win for the University.
“Because we’re reducing our expenses and the amount of water we have to buy, we’re reducing the impact on the local environment through a rainstorm, heavy rainstorm and then thirdly we’re … reusing the water,” Bernotas said.
Inside the plant, water passes over refrigerant inside the chillers, which have a capacity of 7,500 tons of chilled water. The refrigerant removes heat from the water, cooling it to about 42 degrees Fahrenheit. The heat is then transferred through the condenser to a separate loop of water. That water is pumped to the three cooling towers located on the roof.
The cooling towers, located on the roof of the Central Utility Building, are open to the air. Photo: Kara Holsopple / The Allegheny Front
The cooling towers are metal structures that release heat to the open air. Water falls down in sheets from the top of the towers. At the same time, a fan positioned at the top of the cooling tower pulls air up from the outside, using it to cool the water.
During this process, much of the water in the cooling towers is lost to evaporation, which is where the cistern water comes in. The water is pumped from the cistern, and treated before entering the basin of the cooling towers. Bernotas said this reduces use of city water.
“Now, we’re able to use the water that we were given for free via the rain, or the reject water,” Bernotas said.
As evaporation occurs, the water collects sediments. It’s sent to a filtration system and reused.
“We want to dump as little water as absolutely possible down the drain,” said Al Agostinelli, director of building systems and commissioning.
In addition to efforts to reduce wastewater, the Central Utility Building is also implementing energy efficiency measures. During cooler weather, the plant is able to generate chilled water without running any mechanical processes, which is called “free cooling.”
Additionally, the motors that pump water through the chillers would run all the time if it weren’t for the variable frequency drives, which vary the speed of the motors depending on load.
“So we’re not using energy that we don’t need to use anymore,” Agostinelli said.
Future plans
Next, the University is increasing its water recovery efforts. Dan Fisher, assistant vice chancellor of operations and maintenance, said a second cistern is now buried under Mazeroski Field on the lower campus, which will connect to the chilled water plant in Posvar Hall.
“We’re not reclaiming [water] there yet, but [that] is my goal,” Fisher said.
