Q: When Blue Earth County put in the new Justice Center, if I remember right they drilled like 500 wells for a geothermal heating/cooling system. I’m just wondering how that is panning out. I’ve never heard anything about their electric bill or heating bill.
A: The Blue Earth County Justice Center just finished its 10th anniversary year in 2019, so this is a timely question.
And, as far as Ask Us Guy can tell, The Free Press wrote several stories about all of the energy-saving technology and materials used in the 168,000-square-foot, $42 million facility on Mankato’s far eastern side. But there was never a follow-up on whether it worked as planned.
The County Board — when planning for the new home for its jail, courtrooms and district court offices, sheriff’s office and county attorney’s offices — decided to make it a LEED-qualified facility, which was a relatively new thing during the first decade of the 21st century. LEED status — Leadership in Energy and Environmental Design — requires numerous environmentally friendly features.
A big part of the effort to make the heating and air-conditioning more efficient was the geothermal system, which involves water circulating through 48 miles of tubing stretching to 200 feet below ground. With a constant 55-degree subsurface temperature, circulating water deep into the ground provides a head-start when warming the building on cold winter days and in cooling the building during the heat of summer.
“The geothermal is working very well,” said Tim Edwards, physical plant director for the county.
A leak in the system in the building’s first year was found to be just a bad coupling, which was easily fixed, and the system has been running smoothly ever since, Edwards said: “Knock on wood, we haven’t had any issues with the pumps or the pipes or anything out there.”
As for the energy bills, it’s clear the Justice Center is cheap to heat compared to the Historic Courthouse or the Blue Earth County Government Center, both on Fifth Street and both of which have been updated with insulated windows and other energy-efficiency upgrades in recent years.
“If we look at the gas bills, like the boilers downtown, our gas bills up at the Justice Center are very minimal,” Edwards said.
Because the Justice Center is a new building, there’s no before-and-after comparisons available, as there would have been in the geothermal system was added to an existing facility. In addition, not all of the efficiency can be attributed to the heating and cooling system. The building’s design included extra insulation from the foundation to the roof, windows that maximize using available daylight, high-performance windows and glazing, exterior shading devices to keep the building cooler in summer and other energy-efficiency strategies.
It’s hard to compare the building’s electrical consumption to county office buildings because those facilities are in operation only on weekdays, usually for less than half of the day. Even the Public Works Department is closed on weekends, holidays and evenings unless there’s bad weather or another emergency.
By contrast, major portions of the Justice Center — the jail in particular, which has a capacity of nearly 200 beds — are always in use.
“It’s very hard to tell with the electrical bills, being that it’s a 24/7 building. That is our largest building as well,” Edwards said. “We’re also tied to the solar farms, so that’s helping our energy costs as well.”
Edwards is confident the investment in energy efficiency already has been recouped by the energy savings in the Justice Center’s first decade. And he expects the County Board, if it decides to move forward with a new Public Works Department facility in the future, might be inclined to go with another LEED-certified building.
“I think we’d take a peek at it and do some comparisons again,” he said.
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