Cash flow has become somewhat easier to control for nonprofit recreation center Geneva Lakes Family YMCA, in Wisconsin, USA. Some years ago, the center, lead by Executive Director Joe Peyer, decided to replace single-speed drives in the facility’s air handlers and pool pump with new Danfoss drives. Just a year later, they yielded combined annual energy savings of $10,000.
“The drives have been nothing short of fantastic for our facility – and for our cash flow,” says Joe Peyer.
New pump required lower energy usage
The savings came as no surprise for Tim Ruesch, Regional Sales Manager for Innovative Cost Solutions, Green Bay, Wisconsin, who initially suggested the YMCA replace their single-speed pump with a Danfoss VLT® AQUA Drive.
“The single-speed pump was consuming more than 15 kWh around the clock. But pumping full speed all the time wasn’t really necessary. My research showed that the Danfoss VLT® AQUA Drive could deliver with much lower energy (kW) usage,” notes Tim Ruesch.
Taking advantage of the VLT drive’s control capabilities, Tim Ruesch wired it to a digital flow meter to provide the VLT algorithm with flow data to control pump speed. Now, when pool usage and filters require higher pressure to meet the minimum flow requirement, the flow compensation algorithm accelerates the pump speed. When the pool closes for the evening, the algorithm reduces the pump speed.
As a result of the flow compensation and VLT efficiency, the YMCA saw some impressive electricity savings. Joe Peyer says: “Compared to our original 15 kWh pump, the Danfoss drive runs at 8 kWh when the pool is occupied and 2 kWh when we are closed.”
Problem with negative pressure solved
Besides energy savings, the retrofit also brought another specific benefit to the air handling unit that eliminates the smell of chlorine. Executive Director Joe Peyer explains: “Ever since we opened, those air handlers created extreme negative pressure in the building. It was tough to open the doors in the pool area. And then they would slam shut, which was dangerous. I had to put special closures on the door to make sure kids’ fingers didn’t get caught. The negative pressure also caused back-drafting that affected our gas heaters and main boiler. We had nonstop service calls to deal with power vent issues on our gas-fired burners and constant sooting in the boiler.”
To address the problem, Tim Ruesch applied two Danfoss VLT HVAC drives, one rated 15hp, and the other 20hp. The negative air pressure issues were instantly solved, not to mention a reduction in white noise in the pool deck area. Since then, the recreation center has had no unplanned service calls.
Perhaps retrofitted pool pumps and air handlers will also be a solution for other facilities. Tim Ruesch says: “With returns on investment like that, this type of drive retrofit easily sees a payback in 12 to 18 months. We have a lot of indoor water parks, competition pools, and recreation centers around here because of the long winters. These facilities usually operate as public or nonprofit businesses, so they can’t afford the high operating costs of misapplied, single-speed drives on pumps and air handlers.”