16.0 Geothermal Energy Frank R. Leslie, B. S. E. E., M. S. Space Technology, LS IEEE 3/18/2010, Rev (321) Oil ~$80 on 3/18/2010

In Other News... Engineering firm Strategic Energy Solutions Inc. has moved into a new headquarters in Berkley MI that the owner hopes to use as a showcase for clients for state- of-the-art geothermal heating and cooling technology.Strategic Energy Solutions Inc.  A 4,000 square-foot adjacent warehouse will house a new geothermal installation business unit.  Six geothermal pumps buried underneath a rear parking lot serve the two buildings with about 20 tons of heating and cooling capacity – the equivalent of eight to 10 homes

16 Overview: Geothermal Geothermal energy is present within the land and the sea  Internal heat is from initial world accretion from gathering dust and compression of the earth and from radioactive decay This energy can be useful in heating and cooling of air and water, but is somewhat costly to use Active geyser areas are limited in area, but provide much hotter water or steam The energy is inexhaustible in principle, yet local extraction will cool the immediate area in a few years Extraction of energy from deep (~20,000 ft) hot rock is not economic yet

16.0 Definitions: Geothermal Energy HDR – Hot, dry rock: has no natural steam but may receive injected water to emit steam Head – the height of water – the hydraulic height of the water (1 psi = 2.31 ft H 2 O)  For artesian wells, the height that the water will stand above ground level in a pipe Heat Quality – the temperature of the heat Ground Source Heat Pump – extracts from ground or rejects heat to ground to/from and air conditioning heat pump

16.0 Geothermal Energy Active geysers supply steam or hot water for heating in The Geysers, California (824 MW e ) “Hot, dry rock” (HDR) offers potential for injecting water and using the resultant steam to spin a turbine At a lower thermal level, an air conditioner can extract heat from the ground for winter heating or insert energy into the ground to gain a more efficient cooling sink geysers20.html Nearby Calistoga (started 1862) has tourist spas with hot water from springs; also palm reading, water treatments, psychics, mud baths, etc.

16.0 About This Presentation 16.1 History 16.2 Sources 16.3 High Temperature Systems (Steam) 16.4 Low Temperature Systems (Heat Pumps) 16.5 Issues and Trends 16.0 Conclusion

16.1 History Paleo-American Indians used hot springs in this area Hot Springs, Arkansas had $1 hot baths in 1830 First electricity (20kW) from geothermal produced from natural steam in Larderello, Italy in 1904 [Kruger, 1973] New Zealand’s north island gets 6% of its electricity from geothermal energy 1920: test boring in Niland CA 1922: electricity generation in The Geysers 1950: 95°F, 220kW generating plant in Katanga The Geysers CA expanded to 600MW in

16.2 Source of Geothermal Energy Heat stems from radioactive disintegrations of atomic nuclei [Sorensen, 2000], initial cooling from agglomeration in planet formation, and other various processes Hot spots occur where strong convective magma circulation is occurring, usually near continental plate boundaries and mountainous regions Hot dry rock, the most common type, retains convective heat Storage in a developed area may be depleted in 50 years

Sources of Geothermal Energy The western states have most of the higher temperature energy

Sources of Geothermal Energy

Sources of Geothermal Energy U.S. Geothermal power plant locations: 1. The Geysers; 2, Salton Sea; 3. Heber; 4, East Mesa; 5. Coso; 6. Casa Diablo; 7, Amedee; 8, Wendel; 9. Dixie Valley; 10. Steamboat Hot Springs; 11. Beowawe Hot Springs; 12. Desert Peak; 13, Wabuska Hot Springs; 14. Soda Lake; 15, Stillwater; 16. Empire and San Emidio; 17, Roosevelt Hot Springs; 18, Cove Fort.

Mammoth Pacific Power Plant, CA “Located in the eastern Sierra Nevada mountain range in California, showcases the environmentally friendly nature of geothermal power.” ---- ASES policy, 2005

16.3 High Temperature Systems These areas are associated with the “Ring of Fire” volcanic activities around the Pacific Rim Basin Geyser-temperature steam is contaminated with salts that cause corrosion of turbines or engines Removing these salts to protect the machinery is costly Types of geothermal systems  Direct from steam underground  Flash-steam systems take in deep-well hot water (high enthalpy) that is above the boiling point to heat clean water into steam in a heat exchanger  Binary systems that heat a low-boiling-point fluid like butane or propane to drive a closed-loop turbine

16.4 Low Temperature Heat Extraction/Rejection The classic use of earth/water is as a heat sink or source for air conditioning or heating Pipes embedded in the earth carry refrigerant or water and conduct heat from the hotter to cooler substance Since the earth (or water) has a high specific heat in comparison with air, there is good thermal transfer In winter, heat is extracted from the earth by the chilled refrigerant, while in the summer, the hot refrigerant conducts heat to the earth Houses have been built partially underground to moderate the winter and summer temperatures  Dennis Weaver built an “Earthship” house with used tires, aluminum cans, and stucco

Basic Refrigeration Concept Specific heats determine the storage of thermal energy  Air – Btu per cubic foot  Water – Btu per cubic foot, or 3472 times higher Heat pumping works through phase change of the refrigerant; boiling to gas or condensing to liquid Typical refrigerants have boiling points of -40 degrees F When the refrigerant is compressed, heat is released and it liquefies; when decompressed through an expansion valve, it cools as it changes to a gas Reversing the direction of refrigerant travel through the system changes operation from an air conditioner to a heat pump

Basic Refrigeration Diagram Long pipes buried in the ground carry water to and from a heat exchanger The refrigerant absorbs heat from or rejects heat to the water

16.5 Issues and Trends HDR (hot, dry rock) cools locally as the temperature falls with energy extraction  Wells may require redrilling to find new hot regions and to let more heat enter the depleted region  Since the locations are limited, this source of energy may not be economically available  Extraction often requires fracturing of deep rock layers to allow water in and steam out Since sources are geographically limited, the energy is best used locally; too difficult to pipeline elsewhere

16.C Conclusion: Geothermal Geothermal energy is limited in extent as extracting the heat usually exceeds the replenishment rate Hot, dry rock (HDR) is widespread and offers new resources in areas where geyser activity is unknown Direct low-temperature heat transfer for home systems is practical as long as low maintenance is designed into the system Sources of high temperature water or steam are limited and the cost of extraction, maintenance, and operation will remain high in comparison with other sources of energy Geothermal energy likely to remain at 1% of world energy [Kruger, 1973]

Olin Engineering Complex 4.7 kW Solar PV Roof Array Questions?

References: Books Boyle, Godfrey. Renewable Energy, Second Edition. Oxford: Oxford University Press, 2004, ISBN (my preferred text) Brower, Michael. Cool Energy. Cambridge MA: The MIT Press, , TJ807.9.U6B76, ’4’0973. Duffie, John and William A. Beckman. Solar Engineering of Thermal Processes. NY: John Wiley & Sons, Inc., 920 pp., 1991 Gipe, Paul. Wind Energy for Home & Business. White River Junction, VT: Chelsea Green Pub. Co., , TJ820.G57, 621.4’5 Patel, Mukund R. Wind and Solar Power Systems. Boca Raton: CRC Press, 1999, 351 pp. ISBN , TK1541.P , ’2136 Sørensen, Bent. Renewable Energy, Second Edition. San Diego: Academic Press, 2000, 911 pp. ISBN Texter, [MIT] Kruger, Paul and Carel Otto, eds. Geothermal Energy. Stanford CA: Stanford University Press, 1973, Bockris, J. O’M. Energy – The Solar-Hydrogen Alternative. NY: John Wiley & Sons1975. ISBN TJ810.B

References: Websites, etc. Government Lab Good explanation of practical use University of Nevada at Reno Desert Research Institute Brookhaven Laboratories INEEL Lawrence Livermore Labs Sandia National Labs National Renewable Energy Labs More Resources _________________________________________________________________________________ _____________ geothermal.marin.org/ on geothermal energy rredc.nrel.gov/ Site devoted to the decline of energy and effects upon population Federal Energy Regulatory Commission solstice.crest.org/ dataweb.usbr.gov/html/powerplant_selection.html ftp://ftp.consrv.ca.gov/pub/oil/maps/Geothermal/G3-1.pdf