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The second energy use simulation represents the energy usage of the buildings when the existing furnaces <br /> are replaced by new high efficiency furnaces. This model also increases the ventilation for the buildings <br /> to bring them up to current code requirements. <br /> The third energy use simulation represents the energy usage of the buildings when a geothermal HVAC <br /> system with a vertical bore well field is used to heat and cool the buildings. This model includes the same <br /> ventilation rates as the high efficiency furnace model. <br /> The fourth energy use simulation uses the same equipment as the other geothermal option but utilizes the <br /> city's water main as the energy source for the water to air heat pumps instead of a vertical bore well field. <br /> Summary <br /> The summary of the study results are shown in Table 1 and Table 2. <br /> Table 7. Suinmary of Study Results <br /> r � • � � E ». s" .�� � � � � ;� �`,� � � � , <br /> �yr���r� � �°� i������I�) <br /> � a i . <br /> �� y J�y��i4q��i�, <br /> � � � @m <br /> „ � � <br /> � <br /> � y��.� � �� .�. '�- <br /> c� t✓ � <br /> r�`�-E ..�,� �„�_ � � <br /> .�" -'r",s�'"`���:s�,� <br /> High Efficiency Furnace System 47,690 1,743 22% - $90,950 - <br /> Geothermal NVAC w/Well Field 48,460 4,890 30% $2,786 $222,600 47.3 <br /> Geothermal HVAC w/HX 53,130 4,890 32% $3,285 $190,460 30.3 <br /> Table 2. Annual Energy Consumption Comparison <br /> ,���: <br /> • � � �� -. � � � � � <br /> Existing HVAC System 223,730 61.0 7,218 <br /> High Efficiency Furnace System 176,040 53.1 5,475 <br /> Geothermal HVAC System 175,270 40.8 2,328 <br /> Hi h Efficienc Furnace S stem 170,600 36.9 2,328 <br /> Recommendations <br /> It is our recommendation that The City of Orono implement the Geothermal HVAC System with a heat <br /> exchanger connected to the city water main. This conversion has a lower initial cost than the Geothermal <br /> HVAC System with a well field and also reduces the annual operating cost of the three buildings by the <br /> largest amount. This system lowers the annual energy cost and increases the ventilation rates to meet <br /> current code requirements. Additional savings could be realized by providing a more efficient heating <br /> source to replace the electric resistance heating. Rezoning the ductwork according to the current office <br /> layout would increase occupant comfort. Zoning changes and replacement of the resistance heating were <br /> not included in this study. <br /> 005.10.01 Page 4 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 />