By Alexandra Kukulka
The Daily Southtown, Tinley Park, Ill.
MOKENA, Ill. — The new Mokena public safety facility under construction will have double the number of geothermal wells to heat and cool the building, after a geological review of the land found a depth of 500 feet couldn’t be reached.
The geothermal wells will heat and cool the building through water source heat pump units, installed hundreds of feet underground, that draw energy from the earth, said Patrick Callahan, senior principal for Studio GC, the architecture and interiors company designing the building.
“The benefits are that we are not using any combustibles, so there’s no natural gas to heat the building. It’s all electric,” Callahan said. “For one unit of energy, we’re essentially getting two units of measure, which means the building is 50% more efficient than a traditional system. We are using an on-site, renewable source: Mother Earth.”
Initially, the site plan called for 16 wells 500 feet underground, Callahan said. The site plan changed to accommodate 32 wells drilled 250 feet deep, and the Village Board recently hired QC Geothermal to complete the work for $298,200, Callahan said. The system will pay for itself within 13 to 15 years, Callahan said, by savings in maintenance and utility costs.
When determining how many wells and what depth, Callahan said construction crews look at building design and if the building will be heating or cooling dominant.
“The well field itself has characteristics that responds to the type of building,” Callahan said.
When it is hot outside, the system takes the heat inside the building and warms the earth, Callahan said, and when it is cold outside the system draws heat from the earth and warms the building. The water inside the wells is maintained at 55 degrees, he said, so the water source heat pump will have a compressor that either warms or cools the water.
The geothermal wells will be under the parking lot of the station at 191st Street and 104th Avenue, and will connect through pipes, Callahan said. The water travels in one direction within the pipes and circulates to the building and back into the wells within minutes, he said.
“The key here though is we’re not extracting anything from the earth. We’re not taking out any water. We’re not putting in any water. We’re simply leveraging energy with a thermal transfer,” Callahan said.
The police station construction will cost $15.9 million, and it will sit on a 3.5-acre lot the village purchased in 2008. The original construction plans were paused amid the recession, said police Chief Brian Benton, and then because of needed upgrades to the village’s water treatment plant.
The police have worked out of an old firehouse at 10907 Front Street, bought in 1995, that was remodeled into a police station, Benton said.
“It’s only about 5,000 square feet. We’ve definitely outgrown our capacity here,” Benton said.
The facility is expected to open Oct. 30, will be more than 30,000 square feet, with a fitness center, shooting range and a use of deadly force simulator room, Benton said. Geothermal wells will add to the state-of-the art features of the building, he said.
“It’s cleaner, there’s less energy usage, and in the long term its relatively inexpensive, outside of just the initial cost of installing the piping at the onset,” Benton said.
Geothermal wells were developed in the 1970′s, Callahan said, but in about the last 15 years the technology has grown because major manufacturers have started making the parts needed for the wells. In the suburbs, from Aurora to Alsip, there has been an increase in schools and libraries moving toward geothermal well technology.
Benton said while researching geothermal wells, he talked with officials in Country Side who recently implemented the technology.
Matthew Murray, building maintenance technician for Countryside, said the village opened a municipal complex in 2019 that uses geothermal wells and solar panels, making it a certified net zero building. The Countryside municipal complex has 32 geothermal wells at 450 feet, Murray said,
“It’s very low maintenance. It has not caused us any issues, so far,” he said. “You really wouldn’t know we had it unless you walked into the mechanical room.”
The Mokena system, with drilling operations scheduled to start next week, will dehumidify the air and allows for heating and cooling to be used at the same time in different parts of the building, Callahan said.
“That allows for more control for the officers who are there 24 hours a day. We think that’s really important for their well-being as well as having an improved workplace,” Callahan said. “They have a tough enough job, so the building doesn’t need to be more of a challenge for them.”
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