Low-enthalpy geothermal resources have not been utilized to their potential in the past. However, since vast tracts of low-enthalpy geothermal resources exist as energy in the form of differential temperatures, the reserves are estimated to be enormous. As a result, there is growing interest in using this untapped energy in order to reduce carbon dioxide emissions which are the main cause for global warming, one of todays most serious issues as addressed by the U.S. Department of Energy and Environmental Protection Agency documents.
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There has been a surge of interest in electric power generation from low-temperature geothermal energy. The organic Rankine cycle is reviewed for efficiency. A pressure-enthalpy diagram for R-114 (the refrigerant chosen for this study) is given. In the cycle, refrigerant is vaporized, then expanded, to turn the shaft, then condensed, then pumped back into the cycle. The cycle depends on the difference between the evaporating pressure and the condensing pressure. The higher the geothermal water temperature, and the lower the cooling water temperature, the higher the work. Heat loss due to radiation and convection, the movement of refrigerant fluid through the evaporator, in the conversion of expanded power to electrical power, and in use of some actual produced power to pump the cooling water and drive the tower fans--all these heat losses are calculated. The overall saleable power efficiency of the cycle is determined. The efficiency is low, but the binary generator can find a place in a carefully conceived process.
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Reykjavik District Heating Services (Hitaveita Reykjavilcur) was established in 1930. It started small but it has grown continuously and now serves 140,000 inhabitants of Iceland, i.e., 57% of the nation. The Hitaveita uses four different low temperature fields and one high temperature field. The water from the low temperature field is used directly in the radiators and as tap water; but, the energy from the high temperature field is used to heat up fresh water. The energy from the Hitaveita is mainly used for space heating. The cost of the energy is 1.5 cents/kWh and the exploitation of geothermal energy has low environmental impact, especially the low temperature fields. The nearest alternative energy options are electricity and fossil fuels. The cost of heat from those sources is over 5 cents/kWh and the negative impact from those is supposed to be larger than from the geothermal. The conclusion is, therefore, that geothermal energy has economical and environmental advantages the alternative energy sources can not compete with.
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Bibliographic Data file of current published searches from NTIS OIC Library ID#: oitGHC_0723-01.
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Far from the Seismic Belt, and tectonically tranquil, Britain is one of the last countries where one would expect to find signs of geothermal development. It is true that at present such signs are modest; but a start has been made and it now looks as though some useful achievements may result quite soon. Only a few years ago France was thought of as a geothermally barren land; but now something approaching 25,000 dwellings, about 50,000 m2 of greenhouses and some commercial and administrative buildings are being heated by hot underground waters in the vicinity of Paris, while very ambitious plans are afoot for further direct applications of earth heat in other parts of France.
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It is possible to design a canister to cool a borehole gravimeter for Use in geothermal and high-temperature (up to 350/sup 0/C) gas Wells. Repeat surveys with such a gravimeter could (1) help estimate the extent of reservoir plugging in geothermal injection Well after One year of operation and (2) detect compaction of a geothermal aquifer if the change in thickness of the aquifer exceeds 1 m. The instrument could be Used together with conventional logging tools to evaluate radial dependence of density around a Well, or to estimate gas-filled porosity around Wells Drilled with mud. A high-temperature borehole gravimeter could also be Used to evaluate structure and stratigraphy around geothermal and high-temperature gas Wells. Library ID#=oitGHC_0344-01.
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Onion dehydration consists of a continuous operation, belt conveyor using fairly low-temperature hot air from 38 - 104 deg C. Typical processing plants will handle 4500 kg of raw product per hour (single line), reducing the moisture from around 83% to 4% (680 to 820 kg - 1,500 to 1,800 pounds of finished product). An example of a geothermal processing plant is Integrate Ingredients at Empire, Nevada, in the San Emidio Desert. A total of 6.3 million kg (14 million pounds) of dry product are produced annually: 60% onion and 40% garlic. A 130 deg C well provides the necessary heat for the plant.
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A skid mounted test facility has been built for determining conditions at which CO2 flashes from geothermal brines. The system has been checked and operated at one geothermal plant. It performed as designed. The equipment is designed to operate at temperatures and pressures typical of wells near Heber, California. (Nominally IS0C and 300-500 psig). It has heat exchangers which can cool the brine to less than 70C. (The cooling water is re-circulated after being cooled by a forced air heat exchanger). Breakout pressures can be determined for any temperature between 70C and wellhead temperature. OIC Library ID#: oitGHC_3033-01.
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As part of a study of the springs of Utah, reconnaissance data were obtained on the thermal, chemical, and geologic characteristics of the major thermal springs of Utah.
reconnaissance data were obtained on the thermal,
chemical, and geologic characteristics of the major
thermal springs of Utah. Two springs in the State, Roosevelt and Abraham Hot Springs, are in what has been designated
as potentially valuable geothermal areas by the
U. S. Geological Survey. OIT Library ID # oitGHC_5501-01.
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Geothermal waters in the Eastern United States have been used by many people for centuries. Today, the documented direct uses of geothermal waters are mostly related to spasand resorts, with some space heating. In this report, the Eastern United States refers to the states east of the Mississippi River.
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Activity in the field of geothermal energy in Turkey started in 1961 with an inventory of Turkey's hot springs by the Mineral Research and Exploration General Directorate (MTA). Subsequent investigation revealed the great potential of geothermal energy. To enable full utilization of this potential, Turkey was divided into six geothermal regions which are being individually and systematically developed. In 1963, the first geothermal exploration drilling took place in the Agamemnun (Balcova) field which is west of Izmir. At the depth of 40 meters (130 feet) the well yielded a mixture of hot water and steam at the temperature of 124C (255F). The first geothermal field which was utilized for electricity production is in Denizli-Kizildere. Exploration of this field started in 1968. A power plant which has a generation capacity of 20 MWe is now in operation. Another well known geothermal field that was explored in 1982 is Aydin-Germencik field with a temperature of 231C (448F). The names of other well known geothermal fields are lzmir-Seferihisar, Afyon-Omer-Gecek, Canakkalellala, lzmir-Dikili-Bergama, Kutahya-Sima y, and Ankara-Kizilcahamam.
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The source of geothermal fluid for a direct use application is often located some distance away from the user. This requires a transmission pipeline to transport the geothermal fluid. Even in the absence of transmission line requirements, it is frequently advisable to employ other than standard piping materials for in-building or aboveground piping. Geothermal fluid for direct use applications is usually transported in the liquid phase and has some of the same design considerations as water distribution systems. Several factors including pipe material, dissolved chemical components, size, installation method, head loss and pumping requirements, temperature, insulation, pipe expansion and service taps should be considered before final specification.
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In March 1977, the Division of Conservation Research and Technology of the Energy Research and Development Administration (now the Division of Power Systems of the Department of Energy) began a series of interactive planning workshops designed to involve private citizens and representatives of industry, the academic community, public interest groups, and state and local government in the division's planning process. The first workshop, the Energy Conservation R&D Objectives Workshop, hosted by the Coast Community College District of Costa Mesa, California, was held in San Diego on March 6-8, .1977. At the workshop, participants discussed, and made recommendations on, the division's planning process and the Use of the workshops as a mechanism for involving those outside the government in the planning of energy Research and Development (R&D). Library ID#=oitGHC_0336-01.
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The City of Klamath Falls became interested in the possibility of a establishing geothermal district heating system for downtown government buildings in January 1977. Since that time, the project has undergone some controversial and interesting developments that may be of educational value to other communities contemplating such a project. The purpose and content of this article is to identify the historical development of the project; including the design of the system, well owner objections to the project, aquifer testing, piping failure, and future expansion and marketing incentives.
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This package of information is intended to provide background information to developers of geothermal aquaculture projects. The material is divided into eight sections and includes information on market and price information for typical species, aquaculture water quality issues, typical species culture information, pond heat loss calculations, an aquaculture glossary, regional and university aquaculture offices and state aquaculture permit requiremnets.
