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Attachment A r Karges- Faulconbridge, Inc. Engineers City of Roseville Geothermal Master Plan Executive Summary May 14, 2008 Today, buildings in the US consume 65% of the nation's electricity and 35% of the total energy use. Many opportunities exist to minimize the footprint left behind by building energy use. This master plan for the City of Roseville campus looks at reducing the use of fossil fuels by exploring an integrated geothermal system that uses both the waste heat from the ice rinks and the constant temperature of the earth for storage. As part of the process to convert the Roseville Indoor Skating Center to a geothermal system, KFI investigated the feasibility of expanding this system to include the John Rose Oval, the City Hall and Police Station, and the Public Works Facility. The Roseville I ndoor Skating Center and the John Rose Oval generate 11 1260 M B peak Ioad of waste heat as part of the ice making process. While the Indoor Rink can transfer most of this heat to the banquet facility and ice melt, the heat generated while the Oval is operational it is currently being rejected to the atmosphere through an 800 ton cooling tower. Because the Oval's primary hours of operation are November though March, most of this heat can be transferred to the other city buildings when they need it the most. The attached graphs show the hours that heat is being rejected from the Oval and the City Hall/Police Station and Public Works Facility gas consumption in the same months. The waste heat from the Oval can be transferred to the other buildings on campus by adding an underground piping loop connecting all the buildings and adding heat pumps at the City Hall/Police Station and the Public Works Facility. As the Oval only operates four to five months a year, a geothermal well field sized for the cooling load will be required for the heat pumps to operate in the remainder of the year. This well field can also be tied into the Indoor Rink well field. The Oval's cooling tower was installed in 1993 and is an ammonia system. A plate and frame heat exchanger will need to be added to the ammonia loop to transfer the heat to the campus loop system. See attached Figure 1: Schematic of the proposed heat recovery system. At today's energy rates and construction costs, this integrated campus system has a payback between 15-20 years. The cost is divided between the underground piping loop to connect the buildings and the increased cost to add the heat pumps. As the mechanical systems are to be replaced due to life expectancy of the equipment, geothermal systems would be added. The actual energy use for the campus for 2005 was $159,000 and for 2006, it was $166,000. The calculated energy use from our model for a standard geothermal system was $102,400. By adding the waste heat from the Oval to the geothermal system, we calculate a total energy savings of $551000 - $65,000 when these buildings are added to the campus system. These numbers do not include the fire station. 670 Vilest county Road B St. Paul, MN 55113-4527 Ph: 651-771-0880 Fax: 651-771-0878 kfi@kfi-eng.com