Rink

T he Graham Ice Arena Complex in Rochester, Minnesota is an energy-saving marvel. A new integrated geothermal arena (named Graham IV) was built near three existing conventional arenas. Once the new arena was built, all four arenas were combined to create one complex. One of the existing arenas, Graham I, was converted from a conventional refrigeration system to an integrated geothermal system by Harty Mechanical, Inc. Because the system includes many energy-saving options, there are potential future plans to convert the other two conventional rinks to geothermal as well. Waste heat from the ice-making process provides the following benefits: heated spectator seats, in-floor heat in the rink perimeter and mezzanine, and heating of common areas and snow melt pits for resurfacing waste. There are over 10 miles of pipe that make up the ground heat exchanger and 20 miles of pipe in the rink floor. The system was started up in the beginning of November 2007, and it took just under a week to make the ice. Current energy data shows this new geothermal arena is using 50% less energy than a conventional refrigeration system. The conversion of the Graham I arena from a conventional ice refrigeration system to an integrated geothermal ice system took five months. All existing refrigeration equipment in the mechanical room was removed and replaced with four low temperature water-to-water heat pumps that use an earth-friendly refrigerant and high efficiency pumps. The majority of the existing rink floor and piping were left in place with some modifications to the rink floor headers. This is the first conversion in the United States of an existing ice arena to geothermal, utilizing an innovative piping design. The conversion was enhanced by the replacement of all natural gas fueled heating equipment with geothermal heat pumps to serve common areas and the rink. The waste heat from the ice-making process provides heating of the common areas and heating of the domestic water. This system was started up in early October 2007 and also took a week to make the ice. Current energy data shows that this rink (Graham I) is using 50% less energy with the new integrated geothermal system than with the old conventional refrigeration. Not only are these arenas using much less energy, they are providing "free" energy from the ice-making process to melt the snow on the outdoor sidewalks, heat the spectator seats, heat the common areas including locker rooms, provide in-floor heat in the rink perimeter and mezzanine, as well as heating the domestic water. Stay tuned in the next issue for an update on the 'hard data' regarding the efficiencies of this system! ★ An Integrated Geothermal Arena 46 R INK MAGAZ INE march/april 2008 show me the money! ■ Showcasing an idea that can save ice facilities money. 3RD AVE. 16TH STREET Graham Arena I Graham Arena II Graham Arena III Graham Arena IV Utilizing new technologies within a rink can save both energy and money. by PAT HARDY FASCINATING FACTS • Energy savings are estimated to be 40% compared to a conventional rink. • Within the geothermal systems of Graham I and Graham IV there are 45 miles of tubing between the ground exchangers and the rink piping. • These facilities use little to no natural gas in their operation. In-seat heating Ice surface Supply and return lines Ground heat exchanger Geothermal Vault Supply and return to and from well field Low-temp water to heat pumps STAR GRAPHIC

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