Author : Gertsch, Juncal and Associates
Publisher :
Page : pages
File Size : 41,62 MB
Release : 1984
Category : Geothermal engineering
ISBN :
This conceptual engineering study has examined the feasibility of implementing geothermal space and water heating systems at the high school and elemetary school facilities (Surprise Valley School District) in Cedarville, California. The two geothermal wells, which would serve as the energy source for the project, have more than sufficient productive capacity of fluids at temperatures to efficiently heat both school complexes. The wells produce fluids in the temperature range l20-126°F. Peak flow requirements are 66 gpm at the high school and 43 gpm at the elementary school. Average flow requirements are about 25 and 17 gpm, respectively. The fluids are exceptionally clean, at about 178 TDS. Seven engineering design approaches were examined for their technical and economic merit for the proposed application (four for the high school building and three for the elementary school building). The optimum design for the high school is based on the direct use of geothermal fluids in cabinet heaters and unit heaters. The system would displace the schools current reliance on 8-10,000 gallons of fuel oil annually. The optimum design for the elementary school would involve the direct use of geothermal fluids in existing hot water slab systems and the addition of water coils in electrical resistance equipment in the north classroom annex. The geothermal heating system would replace the schools current reliance on about 4200 gallons of fuel oil and 42,885 KWH of electric resistance heating annually. At both installations, existing boiler systems would be retained for backup and infrequent peaking requirements. The cleanliness of the geothermal fluids will permit surface discharge at both project locations. A 25-year life cycle cost-benefit analysis was completed for each school system and the project as a whole. At the elementary school, the savings stream has a Net Present Value (10% DF) of $107,612 on capital expenditures of $73,991 and a 12-year simple payback. At the high school, the savings stream has a Net Present Value of $94,595 on capital expenditures of $118,894 and a simple payback of 22 years. The economic performance of the combined project has a discounted savings stream of $202,207 on capital expenditures of $192,885 and a simple payback of 13-16 years, depending on how closely actual current fuel oil consumption corresponds with predicted heat loads and fuel consumption.