Calhoun Beach Club – Minneapolis, MN

Initial System:  Two residential high rise apartment buildings, one built in the 1920’s with hotel style ball room, meeting rooms, and restaurants; the other apartment building built in 2000.  Both had significant problems with their air cooled chillers short-cycling Spring, Autumn, and Winter.  A new web-based energy management system permitting facility management monitoring from the main corporate offices and anywhere in the world, was desired.

Options:  Persentus developed the business case for the energy saving improvements and completed the installation, with full commissioning, within four months for this project.  The project budget was $895,000 and the project was completed on time and under budget.  The following improvements were made:

• Dry coolers were installed for each of the two buildings.  These provide cooling to obtain low cost cooling during spring, fall, and winter.  This installation also eliminated short cycling of the chillers and will reduce chiller compressor failure occurring annually.
• A web-based energy management system was installed.
• Variable frequency drives were installed.
• Weishaupt boiler burners were installed.
• Parking garage demand ventilation carbon monoxide (CO) control.
• Adjustable kVAR capacitors were installed for power factor correction.

Results:  Persentus procured over $ 27,300 in rebates from the improvements for the project from Xcel Energy and CenterPoint Energy.  The total improvement costs after rebates of $855,200.  The payback on high efficiency equipment and controls was 4.1 years.  Below is a summary of the overall savings on the project.