One of the principal features of the Princeton TIGER project was a ground-source heat exchange system, more than 1,200 cumulative bores, some up to 850-feet deep, which act as thermal batteries to store seasonal heat far below ground. | Photo credit: Halkin Mason Photography
By Arathi Gowda, FAIA, AICP, LEED AP BD+C, LFA
Architecture, engineering and construction professionals strive to build sustainably, but there are always valid reasons why a project falls short of initial north star sustainability goals. However, with a seasoned team that can tune design and construction techniques for market conditions, higher levels of sustainability can be reached.
Recent projects at two universities, both at different points on their sustainability journeys, demonstrate how to achieve these deep green goals. At Princeton University, the new TIGER and CUB facilities support Princeton’s campus-wide decarbonization and water use reduction targets. The Paul J. DiMare Center at the University of Massachusetts Chan Medical School is now the most energy-efficient building on the campus and one of the most energy-efficient research laboratories in all of Massachusetts.
How do these teams do it? Did their clients help them by setting high expectations in their brief? Did they have stellar design and construction partners? Did the policy landscape make it easier to make the case for green? The answer is yes, and the team had the expertise in delivering.
Going Beyond Building as Usual
Photo Credit: Halkin Mason Photography
Although Princeton and UMass Chan are at different points in their sustainability journeys, both had clear goals and laid down a gauntlet to deliver best-in-class sustainability projects.
In 2019, Princeton updated its Sustainability Action Plan with goals for campus operations and building projects, emphasizing designing and developing responsibly. TIGER and CUB were briefed as energy facilities central to Princeton’s goal of achieving net-zero carbon emissions by the university’s 300th anniversary in 2046 by phasing out natural gas, investing in geo-exchange and utilizing thermal storage to significantly reduce peak energy cost.
One of the principal features of the project was a ground-source heat exchange system, more than 1,200 cumulative bores, some up to 850-feet deep, which act as thermal batteries to store seasonal heat far below ground. Two new thermal energy storage (TES) tanks adjoin each facility, storing a ready supply of water to heat and cool the campus daily while shaving peak demand and cost. In combination with on-site and off-site solar photovoltaic (PV) power generation, these integrated systems support Princeton’s transition away from fossil fuel combustion and will be used for the next century. Princeton’s new systems significantly reduce potable water use as well, by harvesting and storing heat instead of rejecting it via cooling towers.
At the University of Massachusetts, the project team was challenged to implement strategies to address emissions associated with designing, building, maintaining, and operating campus buildings and grounds. Since 2013, the Chan Medical School Office of Sustainability has guided public sustainability goals. The Paul J. DiMare Center was developed under the first version of the Chan School of Medicine’s Sustainability Plan, with a strong emphasis on lowering emissions. The 2021–2025 Climate Action Plan further challenged project teams to design buildings with an Energy Use Intensity (EUI) at least 20% lower than the university’s existing building stock.
A critical component of decarbonization and electrification for the Center was ground-source heat exchange. The campus lawn across from the building conceals 75 boreholes drilled 500 feet in the bedrock, providing closed-loop heating and cooling. This system generates 88% of heating and 50% of cooling needs while reducing operational greenhouse gas emissions by 42% compared to the existing central plant. Additionally, advanced energy recovery loops 80% of the energy for heating, cooling, and humidification back into the building and a triple-glazed, articulated pleated façade eliminates perimeter heating and improves thermal comfort. The result is an enviable EUI for a research lab: 130 kBTUs per square foot per year.
Read more about driving innovation with an integrated design process in the July/August Maintenance and Operations digital edition of School Construction News.
Arathi Gowda, FAIA, AICP, LEED AP BD+C, LFA is a principal with ZGF Architects.