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February 22, 2018, Adrian, Michigan – This summer, when Adrian Dominican Sisters and Co-workers enjoy their cool rooms and offices, they might be further comforted in knowing that the air-cooling system is also helping the environment – and taking the Congregation a step further in its sustainability plan.
By April, a new, more energy-efficient chiller system is expected to be completely operational. The system will cool the buildings through water cooled by ice manufactured by the chiller during times of less demand. Manufacturing the ice during the off-peak period realizes a significant savings over making ice during the daytime hours, when the costs per kilowatt hour are significantly higher.
Sister Corinne Sanders, OP, Adrian Dominican Sisters Director of Sustainability, and Joel Henricks, Director of the Motherhouse Facility and Grounds Department, took time recently to explain the former heating and cooling system and the new system.
“The bottom line is, we’re replacing two old chillers with one new chiller that creates ice during the night to save large electrical costs during the day,” Joel said. The chiller acts as a thermal storage system, which, like a battery, creates and stores the energy – in this case, cool air – during the off-peak time of the day to be used during the hottest periods of the day, when the electricity would cost more. Read a detailed explanation of energy storage.
The former system involved three chillers – one large, air-cooled chiller that ran constantly to serve the needs of the Maria and Weber Center buildings, and two water-cooled chillers, which worked only in the warmer months to serve the Regina residence building and the Madden Hall, which houses administrative offices. In the colder months, the Regina and Madden buildings were heated with a boiler.
Heating and cooling for Regina and Madden were handled by two pipes, one to push the heated or cooled water to the buildings and one to return the water back to the chiller or boiler. This caused some problems when the weather changed, Joel explained, because of the complexity of changing from the boiler to the chiller – and because of the natural time it takes for water to cool down or heat up.
Joel said the water-cooled chillers were 27 years old, at the point of having to be rebuilt or replaced. This gave the Motherhouse the opportunity to opt for a more environmentally friendly and efficient system, Joel said. The old water-cooled chillers made use of the R22 refrigerant, which the Environmental Protection Agency (EPA) determined depletes the ozone, adding to global climate change. “The new units are made with a more environmentally friendly refrigerant – 134A,” he added.
Work on the chiller project began in December and is expected to be complete in April, Joel said. The work was contracted through Adrian Mechanical, which has worked with subcontractors such as Krieghoff-Lenawee.
This summer, while the boiler is offline, it will be made more sustainable through a stack economizer, Joel said. Currently, he explained, the boilers blow off 350-degree air as an exhaust. “A big heat load is wasted and blown off into the atmosphere,” he explained. “The new system puts another heat exchanger in the exhaust stack to pull the exhaust heat out and use it to heat water.” Currently, water is heated through use of steamers. The new system will be more efficient and will reduce the use of fossil fuel, Joel said.
The work on the chillers is one of the projects recommended in a 2017 meeting on ways to make the Adrian Dominican Sisters Motherhouse Campus more sustainable. The meeting was in response to one of the Adrian Dominican Congregation’s 2016 General Chapter Enactments, to “sacrifice to mitigate significantly our impact on climate change and ecological degradation.”