Amy Meadows, CPSM, Marketing Specialist, Gannett Fleming
A mechanical engineering study at The Hill School, a preparatory boarding school nestled among mature trees and classically designed buildings in Pottstown, Pennsylvania, showed the need to refresh and renew the school’s heating and cooling systems. The report also gave the school a comprehensive list of all campus assets, enabling it to better manage and inventory equipment.
For the 2010 study, Gannett Fleming, a global infrastructure firm headquartered in Harrisburg, Pennsylvania, assessed campus systems, recommended engineering solutions, and provided probable construction cost opinions and life-cycle cost estimates.
A History of Innovation
The Hill School, referred to as Hill, was founded in 1851 as The Family Boarding School for Boys and Young Men. The school enrolled 25 boys in its first year, and since then has increased annual enrollment to 500 boys and girls today.
Throughout the years, the school has benefited from the innovations and forethought of its overseers and benefactors. In the mid-1950s, Hill installed an outdoor ice skating rink. The refrigeration used to make rink ice was ammonia, an eco-friendly refrigerant. As the demand for comfort cooling on campus increased, school leadership recognized that they had a cooling source right at their fingertips that was not being used during the summertime – the ice skating rink refrigeration plant.
In 1990, an ice tank was installed at the ice rink cooling plant to produce ice at night. By making ice at night when the demand for electricity is lower, Hill benefited from lower electric rates and higher chiller efficiencies. During the day, the ice was melted to produce chilled water that was circulated through newly installed piping located in the existing utility tunnels to air conditioning equipment in the various buildings on campus.
Continuing the Tradition of Energy Efficiency
When the time came to update the 57-year-old chillers and ice tank, school leadership was challenged to find an approach that would enable the school to continue its energy-efficient systems and keep within budgetary constraints. Gannett Fleming mechanical engineers accomplished the goals by installing a new chilled water/ice system refrigerated by a new electric-driven air cooled chiller and a natural gas engine-driven chiller. The gas-driven chiller takes advantage of the natural gas supply already available on campus and can be run as needed during peak cooling periods without increasing electrical cost. This approach of using what the school already had for another purpose demonstrated the sustainable design principle of using “what is in your hand.”
The use of a gas-driven chiller also minimizes additional electrical load, thereby eliminating the need to upgrade the utility service capacity on campus. The elimination of electrical load because of the replacement of the cooling plant with higher efficiency equipment also resulted in a one-time rebate from the electric company totaling more than $39,000.
Replacing the Steam Distribution System
The primary source of heating for the campus is high-pressure steam generated in gas-fired boilers. Steam piping is routed through underground tunnels into each building, where its heating value is transferred to a hot water heating distribution system, or high pressure is reduced to low pressure and distributed to steam heating devices within each building. The steam piping system serving the campus was installed at various times dating from the 1930s to the 1980s, meaning much of the infrastructure was operating beyond its useful life expectancy.
Gannett Fleming’s initial assessment of the steam distribution system indicated that much of the piping was deteriorated and in need of replacement. During the summer of 2012, the project team field surveyed and documented the entire system. The team then installed the replacement system, which is expected to provide approximately 80 years of service for the school.
Not only did the school gain renewed efficiency of their cooling and heating systems, school leadership gained a report with which to develop a capital budget, prioritize infrastructure improvements, and ensure a solid infrastructure for students now and in the future.
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