Direct Heat Use Research Articles

Transboundary geothermal resources of the Mura-Zala basin:a need for joint thermal aquifer management of Slovenia and Hungary

Large transboundary Upper Miocene geothermal sandy aquifers which are widely utilized by both countries for balneological and direct heat purposes exist in the Slovenian-Hungarian border region. In NE Slovenia the total direct heat use was 382 TJ in 2010, while in SW Hungary it was 648 TJ, including utilization from basement reservoirs. The total installed capacity of the 13 Slovenian users was 38.8 MWt, while that of the 29 Hungarian users was 70.6 MWt. Utilisation takes place without harmonized management strategies which might endanger the longterm sustainability of these systems. We aimed to overcome this by delineating a transboundary thermal groundwater body (TTGWB) Mura-Zala with an aerial extent of 4,974 km2 and with vertical extent between depths 500- 2,200 m, which was done based on detailed geological, hydrological, geochemical and geothermal models as well as numerical modelling. The regional groundwater flow in the Mura-Zala TTGWB is from west to east in general, the modeled cross-border flow is approximately 50 1/s. At present, thermal water abstraction rates from the Mura/Újfalu Fm. (61.8 1/s in the Slovenian and 67.3 1/s in the Hungarian part of the TTGWB) does not endanger the good regional quantity status of the water body, and this should be maintained by allowing a maximum increase of thermal water abstraction 3.5 times higher than today. However, to achieve target numbers for an increased proportion of geothermal energy in the total energy mix in both countries, we suggest that increase of thermal efficiency and re-injection should be prioritized apart from the higher thermal water abstraction with setting up limit of the maximum allowable drawdown.

Low grade thermal energy sources and uses from the process industry in the UK

Thermal energy loss in the process industry is a significant issue due to the high temperatures and multiple heat intensive processes involved. High-grade thermal energy is typically recovered within processes. However, lower grade heat is often rejected to the environment.The benefits of capturing and utilising low grade thermal energy are highly dependent on the qualities and properties of the heat in the waste streams. The temperature of the low grade heat stream is the most important parameter, as the effective use of the residual heat or the efficiency of energy recovery from the low grade heat sources will mainly depend on the temperature difference between the source and a suitable sink, e.g. another process or space heating/cooling. In general, the temperatures of these waste heat sources are too low to produce electricity and direct heat use will depend on whether potential user can be found.This paper presents past and current drivers for heat recovery studies. High and low grade heat sources are defined according to the viability of recovery within the processes. Firstly, high grade heat capture within the processes is reviewed. Then, the focus is on the potential for low grade heat capture outside of the original plant. The paper addresses the potential for low grade heat recovery with regard to new incentives and technological advances. Finally, different aspects which influence the decision making for low grade heat recovery in the process industry are discussed. It is concluded that organisational, financial and economic barriers might be overcome and benefits from a holistic vision could be gained with stronger governmental policy and regulation incentives.

Geothermal Hot Water and Space Heating System in Egypt

Direct utilization of geothermal energy refers to the immediate use of the heat energy rather than to its conversion to electrical energy. The primary forms of direct use include heating and cooling. Geothermal energy could be used to supply hot water or could be used with a special equipment (radiators) to make buildings warmer during winter seasons. In general, the geothermal fluid temperatures required for direct heat use are lower than those for economic electric power generation. Most direct use applications use geothermal fluids in the low-to-moderate temperature range between 50o and 150oC. Although Egypt is not characterized by abundant igneous activity, its location in the northeastern corner of the African plate suggests that it possess geothermal resources, especially along its eastern margin. The data indicate that the temperature of 150 oC may be found in the reservoir in the gulf of Suez and red coastal zone. This work designs a geothermal hot water and space heating system to operate in three buildings in a remote area in the Eastern Desert (i.e. school, home & emergency hospital ) and applies to the Umm Huweitat well(sample no. 69 on the Red Sea approximately 20 km north of the city of Safaga.) as a case study.

Geothermal Hot Water and Space Heating System in Egypt

Direct utilization of geothermal energy refers to the immediate use of the heat energy rather than to its conversion to electrical energy. The primary forms of direct use include heating and cooling. Geothermal energy could be used to supply hot water or could be used with a special equipment (radiators) to make buildings warmer during winter seasons. In general, the geothermal fluid temperatures required for direct heat use are lower than those for economic electric power generation. Most direct use applications use geothermal fluids in the low-to-moderate temperature range between 50o and 150oC. Although Egypt is not characterized by abundant igneous activity, its location in the northeastern corner of the African plate suggests that it possess geothermal resources, especially along its eastern margin. The data indicate that the temperature of 150 oC may be found in the reservoir in the gulf of Suez and red coastal zone. This work designs a geothermal hot water and space heating system to operate in three buildings in a remote area in the Eastern Desert (i.e. school, home & emergency hospital ) and applies to the Umm Huweitat well(sample no. 69 on the Red Sea approximately 20 km north of the city of Safaga.) as a case study.

New Tetraalkylborate Initiators for Remote Polymerization

The polymerization of acrylic esters without direct use of light and/or heat is an important goal. We have investigated a system where the activating component is delivered in a flow of a carrier gas which has unrestricted access to a surface covered with to-be-polymerized monomers. The active ingredient (H2O2 vapor) reacts with coating components (tetraalkylborates) to generate free radicals and initiate polymerization in the surface layer. Differences in reactivity are explained by differing oxidation potentials and alkyl substituents on the boron atom. Radical trapping experiments support the mechanism proposed.

Geothermal development in Hungary—country update report 2000–2002

This paper describes the status of geothermal energy utilization—direct use—in Hungary, with emphasis on developments between 2000 and 2002. The level of utilization of geothermal energy in the world increased in this period and geothermal energy was the leading producer, with 70% of the total electricity production, of all the renewable energy sources (wind, solar, geothermal and tidal), followed by wind energy at 28%. The current cost of direct heat use from biomass is 1–5 US¢/kWh, geothermal 0.5–5 US¢/kWh and solar heating 3–20 US¢/kWh. The data relative to direct use in Hungary decreased in this period and the contribution of geothermal energy to the energy balance of Hungary, despite significant proven reserves (with reinjection) of 380 million m 3/year, with a heat content of 63.5 PJ/a at Δ T=40 °C, remained very low (0.25%). Despite the fact that geothermal fluids with temperatures at the surface higher than 100 °C are available, no electricity has been generated. As of 31 December 2002, the geothermal capacity utilised in direct applications in Hungary is estimated to be 324.5 MW t and to produce 2804 TJ/year. Geothermal heat pumps represent about 4.0 MW t of this installed capacity. The quantity of thermal water produced for direct uses in 2002 was approximately 22 million m 3, with an average utilization temperature of 31 °C. The main consumer of geothermal energy is agriculture (68% of the total geothermal heat dedicated to direct uses). The geothermal water is used only in five spas for space heating and sanitary hot water (SHW), although there are 260 spas in the country, and the thermal water produced has an average surface temperature of 68 °C. The total heat capacity installed in the spas is approximately 1250 MW t; this is not provided by geothermal but could be, i.e., geothermal could provide more than three times the geothermal capacity utilized in direct uses by 31 December 2002 (324.5 MW t).

GEOTHERMAL ENERGY FROM THE EARTH: Its Potential Impact as an Environmentally Sustainable Resource

▪ Abstract Geothermal energy technology is reviewed in terms of its current impact and future potential as an energy source. In general, the geothermal energy resource base is large and well distributed globally. Geothermal systems have a number of positive social characteristics (they are simple, safe, and adaptable systems with modular 1–50 MW [thermal (t) or electric (e)] plants capable of providing continuous baseload, load following, or peaking capacity) and benign environmental attributes (negligible emissions of CO2, SOx, NOx, and particulates, and modest land and water use). Because these features are compatible with sustainable growth of global energy supplies in both developed and developing countries, geothermal energy is an attractive option to replace fossil and fissile fuels. In 1997, about 7,000 MWe of base-load generating capacity and over 15,000 MWt of heating capacity from high-grade geothermal resources are in commercial use worldwide. A key question is whether these levels can grow to a point where geothermal energy is more universally available and thus have a significant impact on global energy supplies in the twenty-first century. Such an achievement will require the economic development of low-grade resources.The current status of commercial and emerging technologies for electric power production and direct heat use is reviewed for the major geothermal resources including hydrothermal, geopressured, hot dry rock, and magma. Typically, high-temperature resources (>150°C) provide base-load generating capacity while lower-temperature resources provide energy for geothermally assisted heat pumps and for direct use in domestic, agricultural, and aquacultural heating applications. Critical development issues relating to resource quality and distribution, drilling costs, and reservoir productivity are discussed in the context of their economic impact on production costs. Advanced drilling and improved heat mining methods are suggested as approaches to increase the worldwide use of geothermal energy by reducing field development costs. With these improvements, lower-grade resources can compete in growing global energy markets that are currently controlled by abundant and low-cost fossil fuels.

Sex control and ploidy manipulations in yellow perch (Perca flavescens) and walleye (Stizostedion vitreum)

In both yellow perch (Perca flavescens) and walleye (Stizostedion vitreum), females grow significantly faster and reach a larger ultimate size than males. In addition, reproductive development in both of these species can have a significant negative impact on somatic growth and fillet yield. Accordingly, methods for producing monosex female populations and for inducing sterility, have important potential applications for both commercial fish culture and fisheries management. Of the several available methods for producing monosex female populations in fishes (such as yellow perch and walleye) in which females are homogametic, the preferred method (described herein) may be to treat juveniles with androgens to induce phenotypic sex inversion of genetic females, and to subsequently use sperm from these females to fertilize normal eggs. Initial efforts at inducing sterility focused on the direct use of either heat or hydrostatic pressure shocks to produce triploid yellow perch and walleye. The gonadal development of triploid yellow perch and walleye of both sexes is retarded compared to that of diploids, and triploid yellow perch can have higher fillet yields than diploids. The direct use of heat and pressure shocks to induce triploidy in yellow perch, however, has negative effects on growth that are independent of ploidy status. One way to circumvent this problem is to produce triploids by crossing fertile tetraploids with diploids. To date, methods of producing viable tetraploids (beyond the larval stage) have been developed for yellow perch but not for walleye.

U.S.A. experience in direct heat use

Direct heat use of geothermal energy in the U.S.A. occurs mainly in the western states. A total of 216 projects is operational, with six under construction and 21 planned. The operational projects account for about 2100 TJ/yr (233 MWt-peak) with an average load factor of 29%. The under-construction and planned projects would approximately double the energy use. Not included are an estimated 10,000 TJ (400 MWt-peak) used in enhanced oil recovery. Space and district heating account for almost half (45.8%) of the annual use, whereas greenhouses account for 20.2%, fish farming for 20.7%, industrial processing for 6.7%, and pools and spas for 6.6%. Future growth is expected to be greatest in district heating, where eight proposed projects will produce 1360 TJ annually (149 MWt-peak). Future growth of all direct heat uses in the U.S. is estimated at 8% annually.

Geothermal R&D in developing countries: Africa, Asia and the Americas

The first industrial (3.5 MW) geothermoelectric power-plant installed in the developing countries was that of Pathé, Mexico, in 1964. A further 75 MW geothermoelectric were added in 1973, again in Mexico, at Cerro Prieto. Other countries later followed the Mexican example, with the result that the geothermoelectric capacity installed in the developing nations increased rapidly from 462 MW in 1979 to 1495 MW in 1984. At the moment (1988) the total geothermoelectric capacity in the developing countries is 1949.7 MW, distributed as follows 2 Philippines 894 MW Mexico 700 MW Indonesia 142 MW El Salvador 95 MW Kenya 45 MW Nicaragua 35 MW Turkey 20.6 MW China 17.3 MW Argentina 0.6 MW Zambia 0.2 MW For the moment there are very few non-electric applications of geothermal heat in the developing countries. The most interesting examples in Africa are found in the circum-Mediterranean countries (Algeria, Tunisia) and in Asia in China and Turkey. There are no known plants for the direct use of geothermal heat in Latin-America. The progress of geothermal R&D is very satisfactory in the Philippines, Mexico and Indonesia, fairly satisfactory in Kenya, Ethiopia and some Central-American countries such as El Salvador and Nicaragua, but still at very early stages in most of the other countries. Several nations with favourable geological conditions for the development of geothermal resources have just begun, or have still to begin, their reconnaissance work.

Soft Energy Technologies

The hard and soft energy paths are compared. The soft path for the U.S. combines greatly increased efficiency in using energy, including transitional fossil fuels, with the rapid introduction of ''soft technologies.'' These, the subject of this paper, are defined as diverse renewable sources relatively simple from the user's point of view (though often technically very sophisticated) and matched in scale and in energy quality to the range of end-use needs. Craig et al. have also suggested further criteria--soft technologies are environmentally benign, subject to ''graceful failure,'' foolproof (or resilient), and flexible--but these descriptions, though accurate, are probably derivative rather than essential to the definition. Mr. Lovins feels that a sound energy policy emphasizes the sustainable direct supply and efficient use of heat for buildings and processes and of liquid fuels for transportation, not further central electrification. A wide range of relatively simple-to-use renewable energy sources matched in scale and in energy quality to our range of end-use needs is now available at attractive marginal costs, he states. Such soft technologies appear able to make a prompt and major contribution to energy supply compared to alternative investments in central-electric systems, synfuel plants, and other centralized devices to convert depletable fuelsmore » to premium energy forms.The former technologies appear superior to the latter in costs, rates, geopolitical implications (including nuclear proliferation), and domestic sociopolitical implications (perhaps the key policy determinant). Soft technologies are increasingly being used in practice, to construct smooth transitions (over 50 years or so) to virtually complete reliance on appropriate renewable sources, meanwhile using fossil fuels far more efficiently and cleanly in transitional systems adaptable to soft sources as they are installed. 173 references. (MCW)« less

The Sixth Royal Society Technology Lecture - Nuclear energy for the steel industry

The steel industry, as a major consumer of coking coal and hydrocarbons, is exploring ways to reduce its dependence on these potentially expensive raw materials by making direct use of nuclear heat. Of the present two routes for producing steel, the major one (the hot metal route) employing the blast furnace which reduces iron ore to yield molten iron which is subsequently refined by basic oxygen steelmaking, does not lend itself to the application of nuclear heat; in the second (the cold metal route) recycled steel-or a substitute-is melted in an arc furnace where already today a proportion of the electricity used is generated in nuclear power stations. The development of ‘direct reduction’ processes allows iron ore to be converted to a solid pre-reduced iron product. In the conventional prereduction process, fossil fuels are used as both fuel and as chemical reductant. With nuclear heat, the fossil fuel-re-formed to a suitable reductant-is confined to the chemical role and not used as a source of heat. This reduction stage would be followed by arc melting, as in the present cold metal route. This basic process, which at present constitutes the minor route, could become the major one for the manufacture of steel in the long term. The lecture will discuss the various processes and outline a possible configuration for an eventual nuclear steelworks, together with some of the technical problems involved.

The Shuman Sun-Heat Absorber

MOST of the experimenters who have attempted to make direct use of the sun's heat for the production of power have adopted the practice of greatly concentrating the sun's rays and focussing them on to a comparatively small and strong boiler generating steam at a fairly high pressure. Mr. Frank Shuman has used a concentration of only two to one, though in the next plant, which will be mate rially different (due to certain recommendations of Prof. C. V. Boys, F.R.S.) from the one herein referred to, the concentration will be three to one. The boilers are lamellar, about a yard square, and only about one-quarter inch thick. They are made of thin tinned copper, painted dull black on the outside, with a number of opposed indentations, the tinning holding the two sheets together where these indentations touch.