MANCHESTER — It’s a new school year, and with it will come a new way of heating and cooling the cavernous confines of Parkway South High School: a geothermal system that pipes water through the more than 336,000-square-foot building and nearly 500 feet below ground.
Down there, the water is kept at a stable temperature of 55 to 57 degrees year-round, which will enable the school district to reduce energy use — something it says will save at least $137,000 annually, and an estimated $1.9 million over the next decade.
“We’re eternally trying to turn one dollar into two around here,” said James Swingle, the manager of planning and construction services for Parkway Schools. “Our lowest-hanging fruit is energy.”
The bulk of the work to install the new system has been completed, and it is expected to begin operation around November — or when the calendar gets “out of cooling season,” Swingle said.
From that point, the water already coursing through the building to provide heating or cooling will begin its new subterranean route, helping the school “reduce what our peak requirements are from Ameren,” explained Erik Lueders, Parkway’s director of sustainability and purchasing.
Those efficiency gains are achieved through the transfer of heat “to or from the ground,” the U.S. Department of Energy explained. Since the water is kept at a constant, midrange temperature below ground, less of a change — and therefore, less energy — is needed to heat it or cool it to desired levels.
“It’s able to direct heat where it needs to go,” said Lueders, naming the school’s swimming pool and boiler system as some of the top recipients.
The building’s energy bill this past year was about $420,000, Lueders said — a figure the new geothermal system is expected to slash by around 33%, while cutting electricity consumption by about 35%. Meanwhile, the energy savings from the project dovetail with Parkway’s overall goal to reduce energy use 20% by 2025 from 2015 levels, for the 33 total buildings across its large district, Lueders said.
The technology — officially called a geothermal heat pump system, or a ground-source heat pump — is not to be confused with the geothermal energy found in volcanically active places like Iceland, where hot water and steam drawn from the ground are used for electricity generation, and for heating homes and even greenhouses.
Parkway partnered with Trane, the heating and cooling company, to build its new system. After working with the district on separate energy projects, the company proposed the idea, but still had to win the bid to install it, according to Swingle. Despite the project’s initial $825,000 “cost premium” compared to more conventional cooling-tower alternatives, that “does not account for the overall savings we realize when we consider life-cycle replacement of the cooling tower as compared to the longer-lasting well field,” Lueders said.
The district was well-suited for the project on many fronts, Parkway officials said.
One reason was simply that the suburban campus of Parkway South offered plenty of room.
“We just happen to be lucky because we have land,” said Swingle, adding that entities with similar systems in more crowded areas often have to squeeze them into the available space beneath parking lots when they are being redone.
“Perfect” timing also worked in the district’s favor, Lueders said, with chiller systems in the building reaching the end of their useful life.
While Parkway has made some more visible commitments to new energy technologies — such as adding solar photovoltaic systems across the district — Lueders says lots of benefits sprout from the behaviors, efficiency and system intelligence at work behind the scenes. The new geothermal system is an extension of that approach.
“There’s a lot that we’re doing that’s more out of sight, out of mind,” said Lueders.
Beyond the utilitarian and cost advantages of the system, the district touts its potential as an educational tool for students. Lueders said it represents a firsthand example of “place-based, project-based learning” opportunities about subjects like energy, engineering and climate.
There could be wider use of geothermal systems moving forward.
The technology is compatible with the more efficient, water-reliant systems for heating and cooling that rose to prominence thanks to the energy crisis of the 1970s, Swingle said. Now, a lot of school buildings from that era are reaching the point where various upgrades are due — including those throughout the Parkway School District, built amid the suburban boom from the 1940s to the 1970s.
“In general, a lot of our buildings are going to be coming up on their third-generation of building-wide turnover,” said Swingle. “We definitely want to look at that.”
The tough part, as always, may be getting the money. But Swingle swears it’s worth the investment.
“We can’t spend enough on infrastructure, but we have to be smart and wise about it, because our cash is captive to taxpayers.”