River Falls Municipal Utilities installed 6 solar, hot water panels on the power plant in 2004. The original intent was to create hot water to preheat the engine water jackets.
This is essentially the equivalent of keeping your car “plugged in” during the winter. With the closing of the power plant (hydros are still in operation and generating) and removal of the engines, the original purpose of the panels was no longer needed.
However, with the engines and their accompanying heat gone, there was now a new need for solar thermal (warm air). So through the POWERful Choices! Initiative, the panels were retrofitted to provide warm air into the facility in the colder months.
The system now takes thermal energy collected from 6 solar panels. Fans move the heated air through a radiator style heat exchanger to heat a propylene glycol solution, then a pump circulates the glycol solution through a plate style heat exchanger, where the energy is transferred to the furnace fan and blown into the facility.
To learn more about these solar panels, please feel free to contact Mike Noreen, Conservation and Efficiency Coordinator at 715-426-3467.