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EXECUTIVE SUMMARY <br /> Introduction <br /> MEP Associates has been retained by The City of Orono to perform an engineering and feasibility study on <br /> the City Hall, Council Chambers and Police Department in Orono, Minnesota. The primary objective of <br /> this study is to determine the feasibility of replacing the current HVAC system with a more energy efficient <br /> geothermal system. The geothermal system will decrease operating costs and reduce the buildings carbon <br /> footprint. The research and analyses in this report will assess the economic viability of the geothermal <br /> system, incorporating energy consumption reduction and implementation costs. <br /> Scope <br /> Description of H l/.4 C Systems <br /> Baseline— Existing HVAC System: The City Hall, Council Chambers and Police Department are currently <br /> conditioned by natural gas furnaces with direct expansion (DX) cooling coils. There is one heat recovery <br /> ventilator located in each of the two mechanical rooms to precondition the outside air. In addition, there <br /> are sections of electric resistance baseboard radiation located at the large windows and entrances as well <br /> as electric resistance heaters for the vestibules. The Police Department sally ports have gas fired unit <br /> heaters and no cooling. Many of the occupants have electric space heaters in their work spaces. <br /> Direct Replacement HVAC System: This system would replace the existing natural gas furnaces and DX <br /> cooling with new high efficiency natural gas furnaces and high efficiency DX cooling. New energy <br /> recovery ventilators will be provided to condition the ventilation air. The electric resistance heating and <br /> gas fired unit heaters will remain. New programmable thermostats will be provided with password <br /> protection for controlling temperature setpoints. <br /> Geothermal HVAC System with Vertical Bore Well Field: A vertical bore geothermal HVAC system <br /> would replace the existing natural gas furnaces and DX cooling. Each furnace will be replaced with a <br /> water to air heat pump to handle the heating and cooling. New energy recovery ventilators will be <br /> provided to condition the ventilation air. The electric resistance heating and gas fired unit heaters will <br /> remain. New programmable thermostats will be provided with password protection for controlling <br /> temperature setpoints. <br /> Geothermal HVAC System with City Water Heat Exchanger: This system utilizes the same water to air <br /> heat pumps and configuration as the previous system. This system replaces the vertical bore well field <br /> with a double wall water to water heat exchanger. The heat exchanger will use water diverted from the <br /> city water main to absorb and reject heat from the water to air heat pumps. <br /> Energy Modeling of Hl/AC Systems <br /> The DOE-2 eQUEST simulation engine was used to model the existing HVAC system as well as each of <br /> the other systems included in the study. <br /> The first model established the baseline for the existing HVAC system. This model was calibrated to the <br /> actual utility bills and established the energy requirements of the buildings. <br /> 005.10.01 Page 3 of 18 City of Orono <br /> May 28,2010 Geothermal HVAC Feasibility Study <br /> engineers � consultants � commissioning <br /> MEP Associates,LLC� 7607 Equitable Drive,Eden Prairie,MN 55344�phone:952.224.4488 fax:952.224.4489 �www.mepassociates.com <br />