WorldWideScience

Sample records for district heating steam

  1. Cogeneration steam turbine plant for district heating of Berovo (Macedonia)

    International Nuclear Information System (INIS)

    Armenski, Slave; Dimitrov, Konstantin

    2000-01-01

    A plant for combined heat and electric power production, for central heating of the town Berovo (Macedonia) is proposed. The common reason to use a co-generation unit is the energy efficiency and a significant reduction of environmental pollution. A coal dust fraction from B rik' - Berovo coal mine is the main energy resource for cogeneration steam turbine plant. The heat consumption of town Berovo is analyzed and determined. Based on the energy consumption of a whole power plant, e. i. the plant for combined and simultaneous production of power is proposed. All necessary facilities of cogeneration plant is examined and determined. For proposed cogeneration steam turbine power plant for combined heat and electric production it is determined: heat and electric capacity of the plant, annually heat and electrical quantity production and annually coal consumption, the total investment of the plant, the price of both heat and electric energy as well as the pay back period. (Authors)

  2. Gas-steam turbine plant for cogenerative process at 'Toplifikacija' - Skopje (Joint-Stock Co. for district heating - Macedonia)

    International Nuclear Information System (INIS)

    Cvetkovski, Andrijan

    2003-01-01

    The gas-steam power plant for combined heat and electric power production at A.D. 'Toplifikacija' Skopje - TO 'Zapad' is analyzed and determined. The analyzed plant is consisted of gas turbine, heat recovery steam generator (HRSG) and condensate steam turbine with controlled steam extraction. It operates on natural gas as a main fuel source. The heating of the water for the district heating is dine in the heat exchanger, with // heat of controlled extraction from condensate turbine. The advantages of the both binary plant and centralized co generative production compared with the individual are analyzed. The natural gas consumption of for both specific heating and electrical capacity in join production as well as fuel savings compared to the separate production of the same quantity of energy is also analyzed. (Original)

  3. Steam turbines for nuclear power stations in Czechoslovakia and their use for district heating

    International Nuclear Information System (INIS)

    Drahy, J.

    1989-01-01

    The first generation of nuclear power stations in Czechoslavakia is equipped with 440 MW e pressurized water reactors. Each reactor supplies two 220 MW, 3000 rpm condensing type turbosets operating with saturated steam. After the completion of heating water piping systems, all of the 24 units of 220 MW in Czechoslovak nuclear power stations will be operated as dual purpose units, delivering both electricity and heat. At the present time, second-generation nuclear power stations, with 1000 MW e PWRs, are being built. Each such plant is equipped with one 1000 MW full-speed saturated steam turbine. The turbine is so designed as to permit the extraction of steam corresponding to the following quantities of heat: 893 MJ/s with three-stage water heating (150/60 0 C); and 570 MJ/s with two-stage water heating (120/60 0 C). The steam is taken from uncontrolled steam extraction points. (author)

  4. Results of Steam-Water-Oxygen Treatment of the Inside of Heating Surfaces in Heat-Recovery Steam Generators of the PGU-800 Power Unit at the Perm' District Thermal Power Station

    Science.gov (United States)

    Ovechkina, O. V.; Zhuravlev, L. S.; Drozdov, A. A.; Solomeina, S. V.

    2018-05-01

    Prestarting, postinstallation steam-water-oxygen treatment (SWOT) of the natural circulation/steam reheat heat-recovery steam generators (HRSG) manufactured by OAO Krasny Kotelshchik was performed at the PGU-800 power unit of the Perm District Thermal Power Station (GRES). Prior to SWOT, steam-oxygen cleaning, passivation, and preservation of gas condensate heaters (GCH) of HRSGs were performed for 10 h using 1.3MPa/260°C/70 t/h external steam. After that, test specimens were cut out that demonstrated high strength of the passivating film. SWOT of the inside of the heating surfaces was carried out during no-load operation of the gas turbine unit with an exhaust temperature of 280-300°C at the HRSG inlet. The steam turbine was shutdown, and the generated steam was discharged into the atmosphere. Oxygen was metered into the discharge pipeline of the electricity-driven feed pumps and downcomers of the evaporators. The behavior of the concentration by weight of iron compounds and the results of investigation of cutout specimens by the drop or potentiometric method indicate that the steam-water-oxygen process makes it possible to remove corrosion products and reduce the time required to put a boiler into operation. Unlike other processes, SWOT does not require metal-intensive cleaning systems, temporary metering stations, and structures for collection of the waste solution.

  5. District heating

    International Nuclear Information System (INIS)

    Hansen, L.

    1993-01-01

    The environmental risks and uncertainties of a high-energy future are disturbing and give rise to several reservations concerning the use of fossil fuels. A number of technologies will help to reduce atmospheric pollution. In Denmark special importance is attached to the following: Energy conservation. Efficient energy conversion. Renewable energy sources. District heating, combined production of heat and power. Many agree that district heating (DH), produced by the traditional heat-only plant, and combined heat and power (CHP) have enormous potential when considering thermal efficiency and lowered environmental impacts: The basic technology of each is proven, it would be relatively simple to satisfy a substantial part of the energy demand, and their high efficiencies mean reduced pollution including greenhouse gas emissions. This is especially important in high population density areas - the obviously preferred sites for such energy generation. Compared with individual heating DH can provide a community with an operationally efficient and most often also an economically competitive heat supply. This is particularly true under the circumstances where the DH system is supplied from CHP plants. Their use results in very substantial improvements in overall efficiency. Further environmental improvements arise from the reduced air pollution obtainable in reasonably large CHP plants equipped with flue gas cleaning to remove particles, sulphur dioxide, and nitrogen acids. As a consequence of these considerations, DH plays an important role in fulfilling the space and water heating demand in many countries. This is especially the case in Denmark where this technology is utilised to a very great extent. Indeed, DH is one of the reasons why Denmark has relatively good air quality in the cities. (au)

  6. Nuclear district heating

    International Nuclear Information System (INIS)

    Ricateau, P.

    1976-01-01

    An economic study of nuclear district heating is concerned with: heat production, its transmission towards the area to be served and the distribution management towards the consumers. Foreign and French assessments show that the high cost of now existing techniques of hot water transport defines the competing limit distance between the site and township to be below some fifty kilometers for the most important townships (provided that the fuel price remain stationary). All studies converge towards the choice of a high transport temperature as soon as the distance is of some twenty kilometers. As for fossile energy saving, some new possibilities appear with process heat reactors; either PWR of about 1000MWth for large townships, or pool-type reactors of about 100MWth when a combination with an industrial steam supply occurs [fr

  7. District heating and cooling systems for communities through power-plant retrofit and distribution network. Volume 2. Tasks 1-3. Final report. [Downtown Toledo steam system

    Energy Technology Data Exchange (ETDEWEB)

    Watt, J.R.; Sommerfield, G.A.

    1979-08-01

    Each of the tasks is described separately: Task 1 - Demonstration Team; Task 2 - Identify Thermal Energy Source(s) and Potential Service Area(s); and Task 3 - Energy Market Analysis. The purpose of the project is to establish and implement measures in the downtown Toledo steam system for conserving scarce fuel supplies through cogeneration, by retrofit of existing base- or intermediate-loaded electric-generating plants to provide for central heating and cooling systems, with the ultimate purpose of applying the results to other communities. For Task 1, Toledo Edison Company has organized a Demonstration Team (Battelle Columbus Laboratories; Stone and Webster; Ohio Dept. of Energy; Public Utilities Commission of Ohio; Toledo Metropolitan Area Council of Governments; and Toledo Edison) that it hopes has the expertise to evaluate the technical, legal, economic, and marketing issues related to the utilization of by-product heat from power generation to supply district heating and cooling services. Task 2 gives a complete technical description of the candidate plant(s), its thermodynamic cycle, role in load dispatch, ownership, and location. It is concluded that the Toledo steam distribution system can be the starting point for developing a new district-heating system to serve an expanding market. Battelle is a member of the team employed as a subcontractor to complete the energy market analysis. The work is summarized in Task 3. (MCW)

  8. District heating in Switzerland

    International Nuclear Information System (INIS)

    Herzog, F.

    1991-01-01

    District heating has been used in Switzerland for more than 50 years. Its share of the heat market is less than 3% today. An analysis of the use of district heating in various European countries shows that a high share of district heating in the heat market is always dependent on ideal conditions for its use. Market prospects and possible future developments in the use of district heating in Switzerland are described in this paper. The main Swiss producers and distributors of district heating are members of the Association of District Heating Producers and Distributors. This association supports the installation of district heating facilities where ecological, energetical and economic aspects indicate that district heating would be a good solution. (author) 2 tabs., 6 refs

  9. District heating in Italy

    International Nuclear Information System (INIS)

    Sacchi, E.

    1998-01-01

    The legislative act establishing the electric monopoly virtually shut out the district heating associated with electricity cogeneration, while other laws, issued to counteract the effects of oil shocks, allowed municipal utilities to do so. Thus, district heating has experienced some development, though well below its possibilities. The article analyses the reasons for this lagging, reports district heating data and projects its forecasts against the Kyoto Protocol objectives [it

  10. District heating in Flensburg

    Energy Technology Data Exchange (ETDEWEB)

    Prinz, W.

    1981-01-01

    The majority of our population, but also of our authorities, are still skeptical or even disapproving towards district heating. The reasons of this negative attitude are partly psychological - e.g. the individualism of the Swiss and their dislike for too centralised structures and ''forced connections'' - but also the existence of finished gas supply networks and the fear of considerable pre-investments and torn streets over years. The following article - held as a speech on the information meeting ''District heating and the possible contribution of nuclear energy'' organised by the Swiss Association for Atomic Energy in Bern shows a practical problem solving at the example of the district heating in Flensburg and deals with these questions.

  11. Project No. 6 - Replacement of the heating and steam plant

    International Nuclear Information System (INIS)

    2000-01-01

    At present the Ignalina NPP facilities and Visaginas town are supplied with heat and steam from the district heating facility at Ignalina NPP. A back-up system, dating from 1979, supplies heat and steam when the district heating system is under repair or in case of outages of units 1 and 2. The existing back-up system does no longer meet with applicable technical and safety standards. A breakdown of the back-up system might result in the interruption of the supply to Ignalina NPP of heat and steam necessary for a number of processes, including waste management. Reconstruction of the existing boiler houses is not economically viable option, nor recommendable, for safety reasons, as it would mean the temporary closing of the back-up system. Project activities includes the design, construction and commissioning of the proposed facility, including all licensing documentation

  12. Guidelines for District Heating Substations

    Energy Technology Data Exchange (ETDEWEB)

    2009-07-15

    The present guidelines contain a set of recommendations focusing on planning, installation, use and maintenance of district heating (DH) substations within district heating systems throughout Europe. The recommendations were developed in order to enable readers to develop well-functioning substations and an effective heat and domestic warm water delivery. These guidelines are intended to give the most effective overall solutions for various parts of the customer installation. The guidelines are not meant to specify the different components of the substation such as meters or heat exchangers. The guidelines deal with a wide variety of issues concerning both present systems of today and district heating systems of the future. Specific handling and maintenance recommendations are mainly focused on present modern systems but are also intended to cover the future situation as much as is feasible. For this reason, certain existing systems are not dealt with in these guidelines. For instance, these guidelines do not cover steam systems, systems with temperatures exceeding 110 deg C and pressure levels above 1.6 MPa. The guidelines include a chapter on the heat meter, as the meter and especially the meter installation is always installed simultaneously with the rest of the substation. These guidelines aim to provide best-practice and easy-to-handle recommendations for: - those who are responsible for relations between district heating utilities and customers; - those who own or maintain a building connected to the district heating network; - those who manufacture, plan, purchase, test and install substations. These guidelines do not deal with investment or cost aspects, but in general, Euroheat and Power recommends looking at the lifetime cost of all components of the substation, instead of investment costs alone. An example of this is provided in Chapter 7.8. The Guidelines were developed based on the most optimal operating principles of substations and meters

  13. VII international district heating conference

    International Nuclear Information System (INIS)

    1988-01-01

    The proceedings of the 7th International District Heating Conference contain the full texts of the 89 presented papers of which 11 fall under the INIS Subject Scope. The conference met in seven sessions and dealt with the following problem areas: design and optimization of systems of district heating, integration of the power system and the district heating systems, cooperation of nuclear and fossil burning sources in district heating systems, the use of specific nuclear power plants for heating purposes, questions of the control of systems of district heating, the development of components of heating networks, the reliability and design of heat supply pipes. (Z.M.)

  14. District heating from Forsmark

    International Nuclear Information System (INIS)

    1980-11-01

    The district heating system of Greater Stockholm must be based on other energy sources than oil. Two alternatives are assessed, namely heat from Forsmark or a coal fueled plant in the region of Stockholm. Forsmark 3 can produce both electricity and heat from the year 1988 on. The capacity can be increased by coal fueled blocks. For low electricity use, 115 TWh in the year 1990, the Forsmark alternative will be profitable. The alternative will be profitable. The alternative with a fossile fuelled plant will be profitable when planning for high consumption of electricity, 125 TWh. The Forsmark alternative means high investments and the introduction of new techniques. (G.B.)

  15. Nuclear steam turbines for power production in combination with heating

    International Nuclear Information System (INIS)

    Frilund, B.; Knudsen, K.

    1977-01-01

    The general operating conditions for nuclear steam turbines in district heating system are briefly outlined. The turbine plant can consist of essentially the same types of machines as in conventional district heating systems. Some possible arrangements of back-pressure turbines, back-pressure turbines with condensing tails, or condensing turbines with heat extraction are considered for nuclear power and heat stations. Principles of control for hot water temperature and electrical output are described. Optimization of the plant, considering parallel variations during the year between heat load, cooling water temperature, and required outgoing temperature is discussed. (U.K.)

  16. Waste heat of HTR power stations for district heating

    International Nuclear Information System (INIS)

    Bonnenberg, H.; Schlenker, H.V.

    1975-01-01

    The market situation, the applied techniques, and the transport, for district heating in combination with HTR plants are considered. Analysis of the heat market indicates a high demand for heat at temperatures between 100 and 150 0 C in household and industry. This market for district heating can be supplied by heat generated in HTR plants using two methods: (1) the combined heat and power generation in steam cycle plants by extracting steam from the turbine, and (2) the use of waste heat of a closed gas turbine cycle. The heat generation costs of (2) are negligible. The cost for transportation of heat over the average distance between existing plant sites and consumer regions (25 km) are between 10 and 20% of the total heat price, considering the high heat output of nuclear power stations. Comparing the price of heat gained by use of waste heat in HTR plants with that of conventional methods, considerable advantages are indicated for the combined heat and power generation in HTR plants. (author)

  17. Nuclear heat for industrial purposes and district heating

    International Nuclear Information System (INIS)

    1974-01-01

    Studies on the various possibilities for the application of heat from nuclear reactors in the form of district heat or process steam for industrial purposes had been made long before the present energy crisis. Although these studies have indicated technical feasibility and economical justification of such utilization, the availability of relatively cheap oil and difficulties in locating a nuclear heat source inside industrial areas did not stimulate much further development. Since the increase of oil prices, the interest in nuclear heat application is reawakened, and a number of new potential areas have been identified. It now seems generally recognized that the heat from nuclear reactors should play an important role in primary energy supply, not only for electricity production but also as direct heat. At present three broad areas of nuclear heat application are identified: Direct heat utilization in industrial processing requiring a temperature above 800 deg. C; Process steam utilization in various industries, requiring a temperature mainly in the range of 200-300 deg. C; Low temperature and waste heat utilization from nuclear power plants for desalination of sea water and district heating. Such classification is mainly related to the type and characteristics of the heat source or nuclear reactor which could be used for a particular application. Modified high temperature reactor types (HTR) are the candidates for direct heat application, while the LWR reactors can satisfy most of the demands for process steam. Production of waste heat is a characteristic of all thermal power plants, and its utilization is a major challenge in the field of power production

  18. Solar heat storages in district heating networks

    Energy Technology Data Exchange (ETDEWEB)

    Ellehauge, K. (Ellehauge og Kildemoes, AArhus (DK)); Engberg Pedersen, T. (COWI A/S, Kgs. Lyngby (DK))

    2007-07-15

    This report gives information on the work carried out and the results obtained in Denmark on storages for large solar heating plants in district heating networks. Especially in Denmark the share of district heating has increased to a large percentage. In 1981 around 33% of all dwellings in DK were connected to a district heating network, while the percentage in 2006 was about 60% (in total 1.5 mio. dwellings). In the report storage types for short term storage and long term storages are described. Short term storages are done as steel tanks and is well established technology widely used in district heating networks. Long term storages are experimental and used in connection with solar heating. A number of solar heating plants have been established with either short term or long term storages showing economy competitive with normal energy sources. Since, in the majority of the Danish district heating networks the heat is produced in co-generation plants, i.e. plants producing both electricity and heat for the network, special attention has been put on the use of solar energy in combination with co-generation. Part of this report describes that in the liberalized electricity market central solar heating plants can also be advantageous in combination with co-generation plants. (au)

  19. District heating by the Bohunice nuclear power plant

    International Nuclear Information System (INIS)

    Metke, E.; Skvarka, P.

    1984-01-01

    Technical and economical aspects of district heating by the electricity generating nuclear plants in Czechoslovakia are discussed. As a first stage of the project, 240 MW thermal power will be supplied using bleeding lines steam from the B-2 nuclear power plant at Jaslovske Bohunice to heat up water at a central station to 130 grad C. The maximal thermal power that can be produced for district heating by WWER type reactors with regular condensation turbines is estimated to be: 465 MW for a WWER-440 reactor with two 220 MWe turbines and 950 MW for a WWER-1000 reactor with a Skoda made 1000 MWe turbine using a three-stage scheme to heat up water from 60 grad C to 150 grad C. The use of satelite heating turbines connected to the steam collector is expected to improve the efficiency. District heating needs will de taken into account for siting of the new power plants

  20. Control system for fluid heated steam generator

    Science.gov (United States)

    Boland, J.F.; Koenig, J.F.

    1984-05-29

    A control system for controlling the location of the nucleate-boiling region in a fluid heated steam generator comprises means for measuring the temperature gradient (change in temperature per unit length) of the heating fluid along the steam generator; means for determining a control variable in accordance with a predetermined function of temperature gradients and for generating a control signal in response thereto; and means for adjusting the feedwater flow rate in accordance with the control signal.

  1. Inventory of future power and heat production technologies. Partial report Boilers/Combustion/Steam cycle for district heating and cogeneration; Inventering av framtidens el- och vaermeproduktionstekniker. Delrapport Pannor/Foerbraenning/Aangcykel foer fjaerrvaerme och kraftvaerme

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, Robert (AaF Process, Stockholm (Sweden))

    2008-12-15

    The energy market of today is turbulent and it is quite clear that big changes in the consumption pattern are going to occur, due to the expansion in Asia and the expected Climate Change. The EU has, as a first step, stated in a directive that the consumption of renewable energy in the heat and power sector should be increased to 20 % and in the transportation sector to 10 % by the year 2020, a target which is high above current levels in most of the EU countries. It is reasonable to believe the European demand of renewable energy will create a shortage of biomass and that the development and use of technology for energy production will therefore not only depend on what is technically possible. One scenario is that biomass is mainly used for the markets that have very few alternatives, such as the transportation sector and small scale CHP units. We have today a relatively high electrical consumption through a stable grid and district heating nets in almost all densely populated areas. Large high efficiency power plants combined with heat pump technology will probably prevent any significant expansion of the district heating nets. A third major net for gas distribution seems not to be a feasible solution. Local nets for production of biogas from wet waste for different purposes, including EvGT units with 55% efficiency may however be good solution for some areas. There are a number of cycles and technical solutions to increase the electrical efficiency which could be applied also on smaller plants. The total efficiency will however not increase, only the el/heat ratio and it is not obvious that the higher investment cost for indirect cycles, bottom cycles or extreme steam data in combination with the risk of lower availability is a feasible solution. Especially waste to energy plants, with their need of high utilisation time, are sensitive to long production interruptions. The existing heat sinks in Sweden will however be efficiently used for electrical production

  2. Boise geothermal district heating system

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, P.J.

    1985-10-01

    This document describes the Boise geothermal district heating project from preliminary feasibility studies completed in 1979 to a fully operational system by 1983. The report includes information about the two local governments that participated in the project - the City of Boise, Idaho and the Boise Warm Springs Water District. It also discusses the federal funding sources; the financial studies; the feasibility studies conducted; the general system planning and design; design of detailed system components; the legal issues involved in production; geological analysis of the resource area; distribution and disposal; the program to market system services; and the methods of retrofitting buildings to use geothermal hot water for space heating. Technically this report describes the Boise City district heating system based on 170/sup 0/F water, a 4000 gpm production system, a 41,000 foot pipeline system, and system economies. Comparable data are also provided for the Boise Warm Springs Water District. 62 figs., 31 tabs.

  3. High-power condensation turbine application to district heating

    International Nuclear Information System (INIS)

    Virchenko, M.A.; Arkad'ev, B.A.; Ioffe, V.Yu.

    1982-01-01

    In general outline the role of condensation turbines in NPP district heating is considered. The expediency of expansion of central heating loading of turbines of operating as well as newly designed condensation power plants on the basis of the WWER-1000-type reactors is shown. The principle heat flowsheet of the 1000 MW power turbine is given. An advantage in using turbines with uncontrolled steam bleeding is pointed out [ru

  4. Improving district heating in Kiev

    International Nuclear Information System (INIS)

    Salminen, P.

    2000-01-01

    The district heating modernisation project currently under way in Kiev, the capital of the Ukraine, is the largest project of its type financed by the World Bank. The budget for the five-year project is some USD 250 million of which USD 200 million is financed by the World Bank loan. The target of the project is to improve the city's district heating system, which is owned and operated by Kyivenergo. Consultancy services for the Project Implementation Unit are being provided by Electrowatt-Ekono and financed by the Finnish government

  5. Combined heat and power considered as a virtual steam cycle heat pump

    International Nuclear Information System (INIS)

    Lowe, Robert

    2011-01-01

    The first aim of this paper is to shed light on the thermodynamic reasons for the practical pursuit of low temperature operation by engineers involved in the design and the operation of combined heat and power (CHP) and district heating (DH) systems. The paper shows that the steam cycle of a combined heat and power generator is thermodynamically equivalent to a conventional steam cycle generator plus an additional virtual steam cycle heat pump. This apparently novel conceptualisation leads directly to (i) the observed sensitivity of coefficient of performance of CHP to supply and return temperatures in associated DH systems, and (ii) the conclusion that the performance of CHP will tend to be significantly higher than real heat pumps operating at similar temperatures. The second aim, which is pursued more qualitatively, is to show that the thermodynamic performance advantages of CHP are consistent with the goal of deep, long-term decarbonisation of industrialised economies. As an example, estimates are presented, which suggest that CHP based on combined-cycle gas turbines with carbon capture and storage has the potential to reduce the carbon intensity of delivered heat by a factor of ∼30, compared with a base case of natural gas-fired condensing boilers. - Highlights: → Large-scale CHP systems are thermodynamically equivalent to virtual steam cycle heat pumps. → COPs of such virtual heat pumps are necessarily better than the Carnot limit for real heat pumps. → COPs can approach 9 for plant matched to district heating systems with flow temperatures of 90 deg. C. → CHP combined with CCGT and CCS can reduce the carbon intensity of delivered heat ∼30-fold.

  6. District heating plants in Europe: Recent experience and innovations

    International Nuclear Information System (INIS)

    De Comelli, G.

    1992-01-01

    This paper contains a critical review of recent experience and innovative features encountered in some European district heating plants. The increased application of cogeneration is pointed out, with reference to traditional, as well as, more recent technology which makes use of combined gas-steam cycles. An example of a combined gas-steam cycle is schematically described. The relevance of fluidized bed combustion and interconnection of heat distribution grids, and their consequences to the environmentally-safe and economical employment of the plants, are evidenced

  7. Optimal integration of energy at the Combined Energy Plant in Norrkoeping -Integration of steam, hot water and district heat to biogas plants; Optimal integrering av energianvaendningen vid energikombinatet i Norrkoeping -Integrering av aanga, hetvatten och fjaerrvaerme till biogasanlaeggningar

    Energy Technology Data Exchange (ETDEWEB)

    Benjaminsson, Johan; Goldschmidt, Barbara; Uddgren, Roger

    2010-09-15

    The background of this report is to investigate and highlight the benefits of establishing a biogas plant nearby a combined energy plant where steam and district heat is available. By using heat from the combined energy plant, more biogas can be produced as vehicle fuel instead of being used as fuel to heat the digester, the biogas upgrading plant or the dryer. The project's objective is to analyze where it is interesting with integration of heat to the biogas plant and to compare alternative technologies and possible integration options. The stakeholders of the study are industries with access to organic matter for biogas production and heat producers who can deliver thermal energy into biogas plants. The project was implemented by collection of information from the Haendeloe combined energy plant outside Norrkoeping where there is a cogeneration plant, an ethanol plant and a biogas plant. Case studies for the study have been carried out with proposals regarding how heat flows from the power plant and ethanol plant can be further integrated with the biogas plant. As case studies, both the current design of the biogas plant, as well as a fictional case in which half of all distillery residues was digested, have been evaluated. The case studies show that in today's biogas plant it is not economical to replace the existing biogas upgrading unit with water absorption to chemical absorption. The upgrading cost with water absorption at today's smaller facility is 0.11 kr/kWh and in order to obtain the same total cost of chemical absorption a steam price of 0.15 kr/kWh is required. For large gas flows, chemical absorption is an advantage since the technology is more suitable for upscaling in comparison with water absorption that must be delivered in multiple lines. Nevertheless, a possibility to recover waste heat from chemical absorption is necessary if the technology shall be competitive. If waste heat from both water absorption and chemical absorption

  8. District heating versus local heating - Social supportability

    International Nuclear Information System (INIS)

    Matei, Magdalena; Enescu, Diana; Varjoghie, Elena; Radu, Florin; Matei, Lucian

    2004-01-01

    District heating, DH, is an energy source which can provide a cost-effective, environmentally friendly source of heat and power for cities, but only in the case of well running systems, with reasonable technological losses. The benefits of DH system are well known: environmental friendly, energy security, economic and social advantages. DH already covers 60% of heating and hot water needs in transition economies. Today, 70 % of Russian, Latvian and Belarus homes use DH, and heating accounts for one-third of total Russian energy consumption. Yet a large number of DH systems in the region face serious financial, marketing or technical problems because of the policy framework. How can DH issues be best addressed in national and local policy? What can governments do to create the right conditions for the sustainable development of DH while improving service quality? What policies can help capture the economic, environmental and energy security benefits of co-generation and DH? To address these questions, the International Energy Agency (IEA) hosted in 2002 and 2004 conference focusing on the crucial importance of well-designed DH policies, for exchanging information on policy approaches. The conclusions of the conference have shown that 'DH systems can do much to save energy and boost energy security, but stronger policy measures are needed to encourage wise management and investment. With a stronger policy framework, DH systems in formerly socialist countries could save the equivalent of 80 billion cubic meters of natural gas a year through supply side efficiency improvements. This is greater than total annual natural gas consumption in Italy'. More efficient systems will also decrease costs, reducing household bills and making DH competitive on long-term. This paper presents the issues: -Theoretical benefits of the district heating and cooling systems; - Municipal heating in Romania; - Technical and economic problems of DH systems and social supportability; - How

  9. Heat extraction from turbines of Czechoslovak nuclear power plants for district heating

    International Nuclear Information System (INIS)

    Drahy, J.

    1985-01-01

    Two design are described of SKODA extraction turbines for Czechoslovak nuclear power plants with WWER-440 and WWER-1000 reactors. 220 MW steam turbines were originally designed as pure condensation turbines with uncontrolled steam extraction. Optimal ways are now being sought for their use for heating hot water for district heating. For district heating of the town of Trnava, the nuclear power plant at Jaslovske Bohunice will provide a two-step heating of water from 70 to 120 degC with a heat supply of 60 MW th from one turbine unit. The ratio of obtained heat power to lost electric power is 5.08. Investigations showed the possibility of extracting 85 MW th of heat from uncontrolled steam extraction, this at three-step water heating from 60 to 145 degC, the ratio of gained and lost power being 7.14. Information is presented on the SKODA 220 MW turbine with steam extraction for heat supply purposes and on the 1000 MW turbine with 893 MW th heat extraction. The specifications of both types are given. (Pu)

  10. Nuclear power for district heating

    International Nuclear Information System (INIS)

    Lyon, R.B.; Sochaski, R.O.

    1975-09-01

    Current district heating trends are towards an increasing use of electricity. This report concerns the evaluation of an alternative means of energy supply - the direct use of thermal energy from CANDU nuclear stations. The energy would be transmitted via a hot fluid in a pipeline over distances of up to 40 km. Advantages of this approach include a high utilization of primary energy, with a consequent reduction in installed capacity, and load flattening due to inherent energy storage capacity and transport delays. Disadvantages include the low load factors for district heating, the high cost of the distribution systems and the necessity for large-scale operation for economic viability. This requirement for large-scale operation from the beginning could cause difficulty in the implementation of the first system. Various approaches have been analysed and costed for a specific application - the supply of energy to a district heating load centre in Toronto from the location of the Pickering reactor station about 40 km away. (author)

  11. District heating in sequential energy supply

    International Nuclear Information System (INIS)

    Persson, Urban; Werner, Sven

    2012-01-01

    Highlights: ► European excess heat recovery and utilisation by district heat distribution. ► Heat recovery in district heating systems – a structural energy efficiency measure. ► Introduction of new theoretical concepts to express excess heat recovery. ► Fourfold potential for excess heat utilisation in EU27 compared to current levels. ► Large scale excess heat recovery – a collaborative challenge for future Europe. -- Abstract: Increased recovery of excess heat from thermal power generation and industrial processes has great potential to reduce primary energy demands in EU27. In this study, current excess heat utilisation levels by means of district heat distribution are assessed and expressed by concepts such as recovery efficiency, heat recovery rate, and heat utilisation rate. For two chosen excess heat activities, current average EU27 heat recovery levels are compared to currently best Member State practices, whereby future potentials of European excess heat recovery and utilisation are estimated. The principle of sequential energy supply is elaborated to capture the conceptual idea of excess heat recovery in district heating systems as a structural and organisational energy efficiency measure. The general conditions discussed concerning expansion of heat recovery into district heating systems include infrastructure investments in district heating networks, collaboration agreements, maintained value chains, policy support, world market energy prices, allocation of synergy benefits, and local initiatives. The main conclusion from this study is that a future fourfold increase of current EU27 excess heat utilisation by means of district heat distribution to residential and service sectors is conceived as plausible if applying best Member State practice. This estimation is higher than the threefold increase with respect to direct feasible distribution costs estimated by the same authors in a previous study. Hence, no direct barriers appear with

  12. Rehabilitation of district heating networks

    Energy Technology Data Exchange (ETDEWEB)

    Ottosson, Peter [AaF-Energikonsult Syd AB (Sweden)

    1996-11-01

    Often the choice is between reparation or exchange of a damaged section of the network. If the exchange is based on the wrong assumptions, large sections of undamaged pipelines could be removed. Most important for the district heating company is to decide which strategy to use for the future exchange of the pipelines. Whichever strategy used, it has to based on an assessment of the network and/or assumptions based on that assessment. The question if it is possible extend the life span of the pipelines arises. What is the most economical choice, the exchange or the renovation. (au)

  13. Dynamic behavior of district heating systems

    International Nuclear Information System (INIS)

    Kunz, J.

    1994-01-01

    The goal of this study is to develop a simulation model of a hot water system taking into account the time dependent phenomena which are important for the operational management of such a system. A state of the art literature review has shown that there is no such model considering all parts from the generation of the heat at the plant to its consumption in the connected buildings so far. First, an exhaustive list of all dynamic phenomena occurring in district heating systems has been drawn and analyzed. Considering this list, this thesis proposes that a model which satisfies the criteria listed above can be developed by superposing four sub-models which are a dynamic model of the heat generation plant, a steady state model of the hydraulic calculation of the distribution network, a dynamic model of the thermal behavior of the network and a dynamic model of the heat consumers. The development of the four sub-models starts from the fundamental conservation equations for fluid systems, i.e. the conservation of mass, momentum and energy. The transformations of those general equations into simple calculation formulas show and justify the hypotheses made in the modeling process. The heat generation plant model itself is a set of sub-models: the models for steam boilers, hot water boilers and heat accumulators which take account of the dynamic evolution of the water temperature by a simple form of the energy conservation equation, as well as the steady state models for circulation pumps and pressurizers. Since the velocities in the network pipes are small, a consideration of steady states is adopted. A network model allowing to calculate the hydraulic variables in every point is adopted from the graph theory. The pressures and flow rates in the network are calculated at discrete time steps and they are considered to be constant for the duration between the time steps. (author) figs., tabs., refs

  14. SECURE nuclear district heating plant

    International Nuclear Information System (INIS)

    Nilsson; Hannus, M.

    1978-01-01

    The role foreseen for the SECURE (Safe Environmentally Clean Urban REactor) nuclear district heating plant is to provide the baseload heating needs of primarily the larger and medium size urban centers that are outside the range of waste heat supply from conventional nuclear power stations. The rationale of the SECURE concept is that the simplicity in design and the inherent safety advantages due to the use of low temperatures and pressures should make such reactors economically feasible in much smaller unit sizes than nuclear power reactors and should make their urban location possible. It is felt that the present design should be safe enough to make urban underground location possible without restriction according to any criteria based on actual risk evaluation. From the environmental point of view, this is a municipal heat supply plant with negligible pollution. Waste heat is negligible, gaseous radioactivity release is negligible, and there is no liquid radwaste release. Economic comparisons show that the SECURE plant is competitive with current fossil-fueled alternatives. Expected future increase in energy raw material prices will lead to additional energy cost advantages to the SECURE plant

  15. A good year for district heating

    International Nuclear Information System (INIS)

    Bakken, Stein Arne

    2003-01-01

    In Norway, high prices on electric power have caused economic progress for the district heating companies. The price of district heating is determined by the prices of power and fuel oil. However, the government wants to remove the tax on electricity to the industry, which is the district heating companies' major group of customers, along with public buildings. This is likely to entail a great loss of income

  16. 4th Generation District Heating (4GDH)

    DEFF Research Database (Denmark)

    Lund, Henrik; Werner, Sven; Wiltshire, Robin

    2014-01-01

    This paper defines the concept of 4th Generation District Heating (4GDH) including the relations to District Cooling and the concepts of smart energy and smart thermal grids. The motive is to identify the future challenges of reaching a future renewable non-fossil heat supply as part...... of the implementation of overall sustainable energy systems. The basic assumption is that district heating and cooling has an important role to play in future sustainable energy systems – including 100 percent renewable energy systems – but the present generation of district heating and cooling technologies will have...

  17. Biomass universal district heating systems

    Science.gov (United States)

    Soltero, Victor Manuel; Rodríguez-Artacho, Salvador; Velázquez, Ramón; Chacartegui, Ricardo

    2017-11-01

    In mild climate regions Directive 27/2012 EU application for developing sustainable district heating networks in consolidated urban nucleus is a challenge. In Spain most of the municipalities above 5,000 inhabitants have a reliable natural gas network and individual heating systems at homes. In this work a new heating network paradigm is proposed, the biomass universal heating network in rural areas. This model involves all the economic, legal and technical aspects and interactions between the different agents of the systems: provider company, individual and collective end-users and local and regional administration. The continental region in Spain has 588 municipalities with a population above 1,500 inhabitants close to forest biomass with renewable use. In many of these cases the regulation identifies the ownership of the forest resources use. The universal heating networks are a great opportunity for energy saving of 2,000 GWh, avoiding 2.7 million tons of CO2 emissions and with a global annual savings for end users of 61.8 million of euros. The presented model is easily extrapolated to other small municipalities in Europe. The real application of the model is presented for three municipalities in different locations of Spain where Universal Heating Networks are under development. The analysis show the interest of the integrated model for the three cases with different structural agents and relationships between them. The use of sustainable forest resources, extracted and managed by local companies, strengths circular economy in the region with a potential global economic impact above 200 M€.

  18. Industrial excess heat for district heating in Denmark

    DEFF Research Database (Denmark)

    Bühler, Fabian; Petrovic, Stefan; Karlsson, Kenneth Bernard

    2017-01-01

    analyses excess heat sources from the industrial sector and how they could be used for district heating. This method first allocates excess heat to single production units by introducing and validating a new approach. Spatial analysis of the heat sources and consumers are then performed to evaluate...... the potential for using them for district heating. In this way the theoretical potential of using the excess heat for covering the heating demand of buildings is determined. Through the use of industry specific temperature profiles the heat usable directly or via heat pumps is further found. A sensitivity...... analysis investigates the impact of future energy efficiency measures in the industry, buildings and the district heating grid on the national potential. The results show that for the case study of Denmark, 1.36 TWh of district heat could be provided annually with industrial excess heat from thermal...

  19. Industrial excess heat for district heating in Denmark

    International Nuclear Information System (INIS)

    Bühler, Fabian; Petrović, Stefan; Karlsson, Kenneth; Elmegaard, Brian

    2017-01-01

    Highlights: •Method for utilisation potential of industrial excess heat for district heating. •Industrial excess heat from thermal processes is quantified at single production units. •Linking of industrial excess heat sources and district heating demands done in GIS. •Excess heat recovery using direct heat transfer and heat pumps. •5.1% of the Danish district heating demand could be supplied by industrial excess heat. -- Abstract: Excess heat is available from various sources and its utilisation could reduce the primary energy use. The accessibility of this heat is however dependent amongst others on the source and sink temperature, amount and potential users in its vicinity. In this work a new method is developed which analyses excess heat sources from the industrial sector and how they could be used for district heating. This method first allocates excess heat to single production units by introducing and validating a new approach. Spatial analysis of the heat sources and consumers are then performed to evaluate the potential for using them for district heating. In this way the theoretical potential of using the excess heat for covering the heating demand of buildings is determined. Through the use of industry specific temperature profiles the heat usable directly or via heat pumps is further found. A sensitivity analysis investigates the impact of future energy efficiency measures in the industry, buildings and the district heating grid on the national potential. The results show that for the case study of Denmark, 1.36 TWh of district heat could be provided annually with industrial excess heat from thermal processes which equals 5.1% of the current demand. More than half of this heat was found to be usable directly, without the need for a heat pump.

  20. Technical specifications for the provision of heat and steam sources for INPP and Visaginas. Final report

    International Nuclear Information System (INIS)

    2003-01-01

    In October 1999, the National Energy Strategy was approved by the Lithuanian Parliament. The National Energy Strategy included the decision to close Unit-1 of INPP before 2005. Later is has been decided to close Unit 2 before the end of 2009 as well. The closure and decommissioning will have heavy impact on the heat supply for the city of Visaginas. Unit 1 and Unit 2 of INPP supplies hot water and steam to INPP for process purposes and for space heating of residential and commercial buildings. When Unit 1 is permanently shut down, reliable heat and steam sources independent of the power plants own heat and steam generation facilities are required for safety reasons in the event of shutdown of the remaining unit for maintenance or in an emergency. These steam and heat sources must be operational before single unit operation is envisaged. Provision of a reliable independent heat and steam source is therefore urgent. After both reactors are shut down permanently, a steam source will be needed at the plant for radioactive waste storage and disposal. INPP and DEA has performed a feasibility study for the provision of a reliable heat source for Ignalina Nuclear Power Plant and Visaginas, and the modernisation of Visaginas district heating system. The objective of this project is to prepare technical specifications for the provision of new heat and steam sources for INPP and Visaginas, and for rehabilitation of the heat transmission pipeline between INPP, the back-up boiler station and Visaginas City. The results of the study are presented in detail in the reports and technical specifications: 1. Transient analysis for Visaginas DH system, 2. Non-destructive testing of boiler stations, pump stations and transmission lines, 3. Conceptual design, 4. Technical specifications, Package 1 to 6. The study has suggested: 1. Construction of new steam boiler station, 2. Construction of new heat only boiler station, 3. Renovation of existing back-up heat only boiler station, 4

  1. Vapor generator steam drum spray heat

    International Nuclear Information System (INIS)

    Fasnacht, F.A. Jr.

    1978-01-01

    A typical embodiment of the invention provides a combination feedwater and cooldown water spray head that is centrally disposed in the lower portion of a nuclear power plant steam drum. This structure not only discharges the feedwater in the hottest part of the steam drum, but also increases the time required for the feedwater to reach the steam drum shell, thereby further increasing the feedwater temperature before it contacts the shell surface, thus reducing thermal shock to the steam drum structure

  2. Solar district heating and cooling: A review

    DEFF Research Database (Denmark)

    Perez-Mora, Nicolas; Bava, Federico; Andersen, Martin

    2018-01-01

    and decentralized solar district heating as well as block heating. For the different technologies, the paper describes commonly adopted control strategies, system configurations, types of installation, and integration. Real‐world examples are also given to provide a more detailed insight into how solar thermal...... technology can be integrated with district heating. Solar thermal technology combined with thermally driven chillers to provide cooling for cooling networks is also included in this paper. In order for a technology to spread successfully, not only technical but also economic issues need to be tackled. Hence......Both district heating and solar collector systems have been known and implemented for many years. However, the combination of the two, with solar collectors supplying heat to the district heating network, is relatively new, and no comprehensive review of scientific publications on this topic could...

  3. Hybrid district heating system with heat supply from nuclear source

    International Nuclear Information System (INIS)

    Havelka, Z.; Petrovsky, I.

    1987-01-01

    Several designs are described of heat supply from large remote power sources (e.g., WWER-1000 nuclear power plants with a 1000 MW turbine) to localities where mainly steam distribution networks have been built but only some or none networks for hot water distribution. The benefits of the designs stem from the fact that they do not require the conversion of the local steam distribution system to a hot water system. They are based on heat supply from the nuclear power plant to the consumer area in hot water of a temperature of 150 degC to 200 degC. Part of the hot water heat will be used for the production of low-pressure steam which will be compressed using heat pumps (steam compressors) to achieve the desired steam distribution network specifications. Water of lower temperature can be used in the hot water network. The hot water feeder forms an automatic pressure safety barrier in heat supply of heating or technological steam from a nuclear installation. (Z.M.). 5 figs., 9 refs

  4. Preliminary business plan: Plzen district heating system upgrade

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-06-01

    The district heating system of the City of Plzen, Czech Republic, needs to have physical upgrades to replace aging equipment and to comply with upcoming environmental regulations. Also, its ownership and management are being changed as a result of privatization. As majority owner, the City has the primary goal of ensuring that the heating needs of its customers are met as reliably and cost-effectively as possible. This preliminary business plan is part of the detailed analysis (5 reports in all) done to assist the City in deciding the issues. Preparation included investigation of ownership, management, and technology alternatives; estimation of market value of assets and investment requirements; and forecasting of future cash flow. The district heating system consists of the Central Plzen cogeneration plant, two interconnected heating plants [one supplying both hot water and steam], three satellite heating plants, and cooperative agreements with three industrial facilities generating steam and hot water. Most of the plants are coal-fired, with some peaking units fired by fuel oil.

  5. Heat exchanger, particularly liquid sodium heated steam generator

    International Nuclear Information System (INIS)

    Robin, Marcel; Tillequin, Jean.

    1977-01-01

    This invention relates to a liquid sodium heated steam generator the characteristic of which is an annular distribution chamber fed by two independent and diametrically opposed manifolds on a common horizontal axis, issuing respectively into two adjacent compartments made in the chambers on both sides of a vertical transversal partition containing the axis of the casing and extending perpendicularly to the manifolds, each compartment being itself divided into a number of adjacent sectors marked by folded metal sheets fixed to the distributor and shaped so as to present in pairs and with the chamber opposite the manifold issuing into a compartment two independent ducts for distributing the sodium flow [fr

  6. District heating in Italy: Extent of use

    International Nuclear Information System (INIS)

    Sacchi, E.

    1992-01-01

    The Author surveys the trend that has been established over the last two decades in the use of district heating in Italy. Comparison with the European situation reveals that Italy is lagging behind. The reason for this the Author states is the Italian public's aversion to unknown risks involved in the utilization of innovative technologies associated with cogeneration/district heating (current preference is given to autonomous methane fuelled building space heating systems), and the current opinion of some misinformed public administrations that cogeneration/district heating plants are too costly. Citing the successful campaign by the natural gas industry to promote the public acceptance of methane as a safe, readily available and competitively priced energy source, he suggests that similar efforts be made to have the public also accept cogeneration (with methane fired gas turbines)/district heating as being safe and environmentally, as well as, economically beneficial

  7. Ground Source Geothermal District Heating and Cooling System

    Energy Technology Data Exchange (ETDEWEB)

    Lowe, James William [Ball State Univ., Muncie, IN (United States)

    2016-10-21

    Ball State University converted its campus from a coal-fired steam boiler district heating system to a ground source heat pump geothermal district system that produces simultaneously hot water for heating and chilled water for cooling. This system will include the installation of 3,600 four hundred feet deep vertical closed loop boreholes making it the largest ground source geothermal district system in the country. The boreholes will act as heat exchangers and transfer heat by virtue of the earth’s ability to maintain an average temperature of 55 degree Fahrenheit. With growing international concern for global warming and the need to reduce worldwide carbon dioxide loading of the atmosphere geothermal is poised to provide the means to help reduce carbon dioxide emissions. The shift from burning coal to utilizing ground source geothermal will increase electrical consumption but an overall decrease in energy use and reduction in carbon dioxide output will be achieved. This achievement is a result of coupling the ground source geothermal boreholes with large heat pump chiller technology. The system provides the thermodynamic means to move large amounts of energy with limited energy input. Ball State University: http://cms.bsu.edu/About/Geothermal.aspx

  8. Future Services for District Heating Solutions in Residential Districts

    Directory of Open Access Journals (Sweden)

    Hannele Ahvenniemi

    2014-06-01

    Full Text Available The underlying assumption of this study is that in order to retain the competitiveness while reaching for the EU targets regarding low-energy construction, district heating companies need to develop new business and service models. How district heating companies could broaden their perspective and switch to a more service-oriented way of thinking is a key interest of our research. The used methods in our study are house builder interviews and a questionnaire. With the help of these methods we discussed the potential interest in heating related services acquiring a comprehensive understanding of the customer needs. The results indicate the importance of certain criteria when choosing the heating system in households: easiness, comfort and affordability seem to dominate the house builders’ preferences. Also environmental awareness seems to be for many an important factor when making a decision about the heating of the house. Altogether, based on the results of this study, we suggest that the prospects of district heating could benefit from highlighting certain aspects and strengths in the future. District heating companies need to increase flexibility, readiness to adopt new services, to invest in new marketing strategies and improving the communication skills.

  9. Performance analysis of hybrid district heating system

    DEFF Research Database (Denmark)

    Mikulandric, Robert; Krajačić, Goran; Khavin, Gennadii

    2013-01-01

    District heating system could contribute to more efficient heat generation through cogeneration power plants or waste heat utilization facilities and to increase of renewable energy sources share in total energy consumption. In the most developed EU countries, renewable energy sources have been...... as problems related to transportation, storage and environmental impacts of biomass and waste utilisation. Implementation of heat storages in district heating systems could contribute to integration of intermittent energy sources. Hybridisation of heat production facility combines two or more different energy...... more extensively used in district heating systems either separately or as a supplement to traditional fossil fuels in order to achieve national energy policy objectives. However, they are still facing problems such as high intermittences, high energy production costs and low load factors as well...

  10. Load Management in District Heating Operation

    OpenAIRE

    Li, Hongwei; Wang, Stephen Jia

    2015-01-01

    Smooth operation of district heating system will avoid installation of expensive peak heat boilers, improve plant partial load performance, increase the system redundancy for further network expansion and improve its resilience to ensuresecurity of supply during severe heating seasons. The peak heating load can be reduced through building demand side management. The building thermal mass can be used to shift the heating supply under the circumstance withoutjeopardizing the consumer thermal co...

  11. Toward 4th generation district heating

    DEFF Research Database (Denmark)

    Li, Hongwei; Svendsen, Svend; Dalla Rosa, Alessandro

    2014-01-01

    In many countries, district heating (DH) has a key role in the national strategic energy planning. However, tighter legislation on new and future buildings requires much less heating demand which subsequently causes relative high network heat loss. This will make current DH system uneconomical co...

  12. Increased system benefit from cogeneration due to cooperation between district heating utility and industry

    Energy Technology Data Exchange (ETDEWEB)

    Danestig, M.; Henning, D. [Division of Energy Systems, Department of Mechanical Engineering, Linkoping Institute of Technology, Linkoping (Sweden)

    2004-07-01

    District heating and steam supply in the town Oernskoeldsvik in northern Sweden is in focus for this study. Low temperature waste heat from pulp manufacturing in the Donisjoe mill is now utilised for district heating production in heat pumps, which dominate district heating supply. Based on this traditional cooperation between the local district heating utility and the pulp industry, the parties discuss a partial outsourcing of the industrial steam supply to the utility, which may enable beneficial system solutions for both actors. The local utility must find a new location for a heating plant because a railway line is being built at the heat pump site. Planning for a new combined heat and power production (CHP) plant has started but its location is uncertain. If the plant can be situated close to the mill it can, besides district heating, produce steam, which can be supplied to adjacent industries. The municipality and its local utility are also considering investing in a waste incineration plant. But is waste incineration suitable for Ornskoeldsvik and how would it interact with cogeneration. Alternative cases have been evaluated with the MODEST energy system optimisation model, which minimises the cost for satisfying district heating and steam demand. The most profitable solution is to invest in a CHP plant and a waste incineration plant. Considering carbon dioxide emissions, the results from applying a local or a global perspective are remarkably different. In the latter case, generated electricity is assumed to replace power from coal condensing plants elsewhere in the North-European power grid. Therefore, minimum global CO{sub 2} emissions are achieved through maximal electricity production in a CHP plant. From this viewpoint, waste incineration should not be introduced because it would obstruct cogeneration. The study is carried out within the program Sustainable municipality run by the Swedish Energy Agency. (orig.)

  13. Swedish district heating - owners, prices and profitability

    International Nuclear Information System (INIS)

    Andersson, Sofie; Werner, S.

    2001-01-01

    Owners, prices and profitability are examined in this report for 152 Swedish district heating companies during 1999. Only public information available has been used: Prices from a national annual consumer study, energy supplied, lengths of district heating pipes installed, and average prices for energy supplied. These companies are responsible for 96 % of all district heat supplied in Sweden. District heating systems owned by municipalities were responsible for 65 % of all district heat supply, while the share of power companies was 34 %. Other private owners accounted for 1 %. Only 12 % of the board members are women and more than 40 % of the companies have no woman in the board. The prices gathered by the annual consumer study are good estimates of the price level of district heating in Sweden. The average revenues are only 4,1 % lower than the effective average of prices gathered. Price of district heating decrease with size and market share. Use of combined heat and power plants decrease prices slightly. Lower prices with size can mainly be explained by lower energy supply costs. Calculated rates of return in relation to calculated replacement values increase slightly by size and are almost independent of age and market share. The purport of these conclusions is that the district heating companies share the cost reduction from size with their customers, while the whole benefit from high market shares is repaid to the customers. Calculated rates of return vary among the owner groups examined. Lower rates are accepted by municipalities, while power companies have higher rates at the average costs used. Total replacement costs for the 152 companies has been estimated to 89 billion Swedish crowns or 10 billion Euro. Only correlation analyses using one dimension have been used in this study. A higher degree of quality can be obtained by using multi-dimensional analyses

  14. Thermodynamic analysis and performance assessment of an integrated heat pump system for district heating applications

    International Nuclear Information System (INIS)

    Soltani, Reza; Dincer, Ibrahim; Rosen, Marc A.

    2015-01-01

    A Rankine cycle-driven heat pump system is modeled for district heating applications with superheated steam and hot water as products. Energy and exergy analyses are performed, followed by parametric studies to determine the effects of varying operating conditions and environmental parameters on the system performance. The district heating section is observed to be the most inefficient part of system, exhibiting a relative irreversibility of almost 65%, followed by the steam evaporator and the condenser, with relative irreversibilities of about 18% and 9%, respectively. The ambient temperature is observed to have a significant influence on the overall system exergy destruction. As the ambient temperature decreases, the system exergy efficiency increases. The electricity generated can increase the system exergy efficiency at the expense of a high refrigerant mass flow rate, mainly due to the fact that the available heat source is low quality waste heat. For instance, by adding 2 MW of excess electricity on top of the targeted 6 MW of product heat, the refrigerant mass flow rate increases from 12 kg/s (only heat) to 78 kg/s (heat and electricity), while the production of 8 MW of product heat (same total output, but in form of heat) requires a refrigerant mass flow rate of only 16 kg/s. - Highlights: • A new integrated heat pump system is developed for district heating applications. • An analysis and assessment study is undertaken through exergy analysis methodology. • A comparative efficiency evaluation is performed for practical applications. • A parametric study is conducted to investigate how varying operating conditions and state properties affect energy and exergy efficiencies.

  15. Optimising corrosion monitoring in district heating systems

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Thorarinsdottir, R.I.; Andersen, A.

    2002-01-01

    A three-year project - financially supported by the Nordic Industrial Fund - on monitoring of corrosion in district heating systems has been initiated with participation of researchers and industrial partners in Denmark, Finland, Iceland, Norway and Sweden. The primary objective of the project...... is to improve the quality control in district heating systems by corrosion monitoring. In Danish systems electrochemical impedance spectroscopy (EIS), linear polarisation resistance (LPR), high-sensitive electrical resistance (ER) technology, crevice corrosion probes, as well as weight loss coupons...

  16. Urban district heating using nuclear heat - a survey

    International Nuclear Information System (INIS)

    Beresovski, T.; Oliker, I.

    1979-01-01

    The use of heat from nuclear power plants is of great interest in connection with projected future expansions of large urban district heating systems. Oil price escalation and air pollution from increased burning of fossil fuels are substantial incentivers for the adoption of nuclear heat and power plants. The cost of the hot water piping system from the nuclear plant to the city is a major factor in determining the feasibility of using nuclear heat. To achieve reasonable costs, the heat load should be at least 1500 MW(th), transport temperatures 125-200 0 C and distances preferably 50 km or less. Heat may be extracted from the turbines of conventional power reactors. Alternatively, some special-purpose smaller reactors are under development which are specially suited to production of heat with little or no power coproduct. Many countries are conducting studies of future expansions of district heating systems to use nuclear heat. Several countries are developing technology suitable for this application. Actual experience with the use of nuclear heat for district heating is currently being gained only in the USSR, however. While district heating appears to be a desirable technology at a time of increasing fossil-fuel costs, the use of nuclear heat will require siting of nuclear plants within transmission radius of cities. The institutional barries toward use of nuclear heating will have to be overcome before the energy conservation potential of this approach can be realized on a significant scale. (author)

  17. Industrial waste heat for district heating

    International Nuclear Information System (INIS)

    Heitner, K.L.; Brooks, P.P.

    1982-01-01

    Presents 2 bounding evaluations of industrial waste heat availability. Surveys waste heat from 29 major industry groups at the 2-digit level in Standard Industrial Codes (SIC). Explains that waste heat availability in each industry was related to regional product sales, in order to estimate regional waste heat availability. Evaluates 4 selected industries at the 4-digit SIC level. Finds that industrial waste heat represents a significant energy resource in several urban areas, including Chicago and Los Angeles, where it could supply all of these areas residential heating and cooling load. Points out that there is a strong need to evaluate the available waste heat for more industries at the 4-digit level. Urges further studies to identify other useful industrial waste heat sources as well as potential waste heat users

  18. Industrial Heat Pump for a High Temperature District Heating Application

    DEFF Research Database (Denmark)

    Poulsen, Claus Nørgaard

    by excess thermal energy from thermal solar panels. An industrial heat pump system using the natural refrigerant ammonia, is extracting the thermal energy from the storage when needed, and produce hot water at 85°C, for the district heating grid. The heat pump also acts as contributor to electricity grid...

  19. Heat pumps in district heating networks

    DEFF Research Database (Denmark)

    Ommen, Torben Schmidt; Markussen, Wiebke Brix; Elmegaard, Brian

    constraints limit the power plants. Efficient heat pumps can be used to decouple the constraints of electricity and heat production, while maintaining the high energy efficiency needed to match the politically agreed carbon emission goals. The requirements in terms of COP, location, capacity and economy...... and strategic planning in the energy sector. The paper presents a case study of optimal implementation of heat pumps in the present energy system of the Copenhagen area. By introduction of the correct capacity of heat pumps, a 1,6 % reduction in fuel consumption for electricity and heat production can...

  20. Modelling of steam condensation in the primary flow channel of a gas-heated steam generator

    International Nuclear Information System (INIS)

    Kawamura, H.; Meister, G.

    1982-10-01

    A new simulation code has been developed for the analysis of steam ingress accidents in high temperatures reactors which evaluates the heat transfer in a steam generator headed by a mixture of helium and water steam. Special emphasis is laid on the analysis of steam condensation in the primary circuit of the steam generator. The code takes wall and bulk condensation into account. A new method is proposed to describe the entrainment of water droplets in the primary gas flow. Some typical results are given. Steam condensation in the primary channel may have a significant effect on temperature distributions. The effect on the heat transferred by the steam generator, however, is found to be not so prominent as might be expected. The reason is discussed. A simplified code will also be described, which gives results with reasonable accuracy within much shorter execution times. This code may be used as a program module in a program simulating the total primary circuit of a high temperature reactor. (orig.) [de

  1. Mechanical design of a sodium heated steam generator

    International Nuclear Information System (INIS)

    Chetal, S.C.

    1975-01-01

    FBTR steam generator is a once through type unit consisting of four 12.5 MW thermal modules generating a total of 74 tons per hour of steam at 125 bar and 480 0 C. This paper outlines the mechanical design of such type of steam generator with emphasis on special design problems associated with this type of sodium to water steam heat exchanger, namely, thermal cycling of transition zone where nucleate boiling changes over to film boiling, application of pressure vessel design criteria for transient pressures, thermal stress evaluation resulting from differential expansion between shell and tube in this typical configuration, sodium headers support design, thermal sleeve, design, thermal shock analysis in thick tubes, thermal stress resulting from stratification and stability of expansion bends against vibration. Some of the possible design changes for the future large size steam generator are outlined. (author)

  2. New nuclear heat sources for district heating

    International Nuclear Information System (INIS)

    Lerouge, B.

    1975-01-01

    The means by which urban oil heating may be taken over by new energy sources, especially nuclear, are discussed. Several possibilities exist: pressurized water reactors for high powers, and low-temperature swimming-pool-type process-heat reactors for lower powers. Both these cases are discussed [fr

  3. Energy cascading in large district heating systems

    International Nuclear Information System (INIS)

    Mayer, F.W.

    1978-01-01

    District heat transfer is the most economical utilization of the waste heat of power plants. Optimum utilization and heat transfer over large distances are possible because of a new energy distribution system, the ''energy cascading system,'' in which heat is transferred to several consumer regions at different temperature ranges. It is made more profitable by the use of heat pumps. The optimum flow-line temperature is 368 0 K, and the optimum return-line temperature is 288 0 K, resulting in an approximately 50% reduction of electric power loss at the power plant

  4. Load Management in District Heating Operation

    DEFF Research Database (Denmark)

    Li, Hongwei; Wang, Stephen Jia

    2015-01-01

    Smooth operation of district heating system will avoid installation of expensive peak heat boilers, improve plant partial load performance, increase the system redundancy for further network expansion and improve its resilience to ensure security of supply during severe heating seasons. The peak...... heating load can be reduced through building demand side management. The building thermal mass can be used to shift the heating supply under the circumstance without jeopardizing the consumer thermal comfort. In this paper, the multi-agent framework is applied to a simplified building dynamic model...

  5. Proposal for a district heat supply system

    International Nuclear Information System (INIS)

    Alefeld, G.

    1976-01-01

    A district heating scheme is proposed which makes it possible to use the waste heat from power stations for the supply of households and industry. The heat is stored by evaporation of ammonia salts or liquids with dissolved salts. Both substances are transported on existing rail- or waterways to heating stations near the consumers, and the heat recovered by reaction of the two components. Then the product of reaction is transported back to the power stations, and reactivated by heat again. Based on a cost estimation, it can be shown that the proposed heat transport with heat trains or ships, at distances up to 100 km, results in heat costs which are to-day already below that of heat from fuel oil. The investment required for the heat transport system is unusually low due to the use of transport ways which already exist. The district heating system is not only favourable in respect of the environment, but actually reduces its present strain, both at the consumer and at the power stations. The technical advantages of the suggested concept, especially the possibility of introducing it in stages, are discussed. The consequences for the national economy regarding the safety of supply and the trade balance, as well as for the public transport undertakings, are obvious, and therefore not included in the paper. (orig.) [de

  6. Shortage of energy increases profitability of district heating

    International Nuclear Information System (INIS)

    2003-01-01

    Increased demand will cause the price of district heating to increase, but not to the level of the price of electricity. The cheapest heating alternative in Denmark, Norway and Sweden is district heating. In Norway, district heating is developed primarily for commercial buildings and housing cooperatives. Thirty per cent of all buildings under construction are prepared for district heating and the percentage will increase strongly in the coming time. The total net production of district heating in Norway in 2001 was 2000 GWh, which is only a small part of the total potential for district heating

  7. District heating and heat storage using the solution heat of an ammonia/water system

    International Nuclear Information System (INIS)

    Taube, M.; Peier, W.; Mayor, J.C.

    1976-01-01

    The article describes a model for the optimum use of the heat energy generated in a nuclear power station for district heating and heat storage taking account of the electricity and heat demand varying with time. (HR/AK) [de

  8. Corrosion Fatigue in District Heating Water Tanks

    DEFF Research Database (Denmark)

    Maahn, Ernst Emanuel

    1996-01-01

    Three candidate materials for construction of buffer tanks for district heating water have been tested for corrosion fatigue properties in a district heating water environment. The investigation included Slow Strain Rate Testing of plain tensile specimens, crack initiation testing by corrosion...... fatigue of plain tensile specimens and crack growth rate determination for Compact Tensile Specimens under corrosion fatigue conditions. The three materials are equal with respect to stress corrosion sensibility and crack initiation. Crack growth rate is increased with a factor of 4-6 relative to an inert...

  9. Stress analysis of HTR-10 steam generator heat exchanging tubes

    International Nuclear Information System (INIS)

    Dong Jianling; Zhang Xiaohang; Yin Dejian; Fu Jiyang

    2001-01-01

    Steam Generator (SG) heat exchanging tubes of 10 MW High Temperature Gas Cooled Reactor (HTR-10) are protective screens between the primary loop of helium with radioactivity and the secondary loop of feeding water and steam without radioactivity. Water and steam will enter into the primary loop when rupture of the heat exchanging tubes occurs, which lead to increase of the primary loop pressure and discharge of radioactive materials. Therefore it is important to guarantee the integrity of the tubes. The tube structure is spiral tube with small bending radius, which make it impossible to test with volumetric in-service detection. For such kind of spiral tube, using LBB concept to guarantee the integrity of the tubes is an important option. The author conducts stress analysis and calculation of HTR-10 SG heat exchanging tubes using the FEM code of piping stress analysis, PIPESTRESS. The maximum stress and the dangerous positions are obtained

  10. Facility with a nuclear district heating reactor

    International Nuclear Information System (INIS)

    Straub, H.

    1988-01-01

    The district heating reactor has a pressure vessel which contains the reactor core and at least one coolant conducting primary heat carrier surrounded by a heat sink. The pressure vessel has two walls with a space between them. This space is connected with a container which contains air as heat isolating medium and water as heat conducting medium. During the normal reactor operation the space is filled by air from the container with the aid of a blower, whereas in the case of a break-down of the cooling system it is filled by water which flows out of the container by gravity after the blower has been switched off. The after-heat, generated in the reactor core during cooling break-down, is removed into the heat sink surrounding the pressure vessel in a safe and simple way. 6 figs

  11. Woodfuel procurement strategies of district heating plants

    International Nuclear Information System (INIS)

    Roos, A.; Bohlin, F.; Hektor, B.; Hillring, B.

    2003-01-01

    Woodfuel use in the Swedish district heating sector increased significantly from 1985 to 1999. This study analysed strategies and considerations concerning woodfuel procurement in district heating plants. Priorities and concerns in the industry involved an increased woodfuel share, ambitions to create an environmental image, cost minimisation, awareness about the role of energy policies for fuel choice, improvement of woodfuel quality and the ambition to maintain a competitive woodfuel market with several suppliers. Factor analysis yielded five dimensions in the woodfuel procurement strategies among the district heating companies: (1) increased woodfuel use; (2) import; (3) spot market woodfuel purchases; (4) focus on refined woodfuels; and (5) using price only when deciding whether to use woodfuels or other fuels. Five clusters were defined along the three strategy dimensions (1)-(3). The clusters differed concerning size, experiences from the introduction of woodfuels, perceptions about woodfuels and strategies employed to date. This paper describes different strategies that the district heating companies apply on the woodfuel market. The conclusion is that policies should consider this diversity in procurement strategies, mitigate their negative side-effects and assist to make them cost-effective. (author)

  12. Steam injection for heavy oil recovery: Modeling of wellbore heat efficiency and analysis of steam injection performance

    International Nuclear Information System (INIS)

    Gu, Hao; Cheng, Linsong; Huang, Shijun; Li, Bokai; Shen, Fei; Fang, Wenchao; Hu, Changhao

    2015-01-01

    Highlights: • A comprehensive mathematical model was established to estimate wellbore heat efficiency of steam injection wells. • A simplified approach of predicting steam pressure in wellbores was proposed. • High wellhead injection rate and wellhead steam quality can improve wellbore heat efficiency. • High wellbore heat efficiency does not necessarily mean good performance of heavy oil recovery. • Using excellent insulation materials is a good way to save water and fuels. - Abstract: The aims of this work are to present a comprehensive mathematical model for estimating wellbore heat efficiency and to analyze performance of steam injection for heavy oil recovery. In this paper, we firstly introduce steam injection process briefly. Secondly, a simplified approach of predicting steam pressure in wellbores is presented and a complete expression for steam quality is derived. More importantly, both direct and indirect methods are adopted to determine the wellbore heat efficiency. Then, the mathematical model is solved using an iterative technique. After the model is validated with measured field data, we study the effects of wellhead injection rate and wellhead steam quality on steam injection performance reflected in wellbores. Next, taking cyclic steam stimulation as an example, we analyze steam injection performance reflected in reservoirs with numerical reservoir simulation method. Finally, the significant role of improving wellbore heat efficiency in saving water and fuels is discussed in detail. The results indicate that we can improve the wellbore heat efficiency by enhancing wellhead injection rate or steam quality. However, high wellbore heat efficiency does not necessarily mean satisfactory steam injection performance reflected in reservoirs or good performance of heavy oil recovery. Moreover, the paper shows that using excellent insulation materials is a good way to save water and fuels due to enhancement of wellbore heat efficiency

  13. A nuclear reactor for district heating

    International Nuclear Information System (INIS)

    Bancroft, A.R.; Fenton, N.

    1989-07-01

    Global energy requirements are expected to double over the next 40 years. In the northern hemisphere, many countries consume in excess of 25 percent of their primary energy supply for building heating. Satisfying this need, within the constraints now being acknowledged for sustainable global development, provides an important opportunity for district heating. Fuel-use flexibility, energy and resource conservation, and reduced atmospheric pollution from acid gases and greenhouse gases, are important features offered by district heating systems. Among the major fuel options, only hydro-electricity and nuclear heat completely avoid emissions of combustion gases. To fill the need for an economical nuclear heat source, Atomic Energy of Canada Limited has designed a 10 MW plant that is suitable as a heat source within a network or as the main supply to large individual users. Producing hot water at temperatures below 100 degrees C, it incorporates a small pool-type reactor based on AECL's successful SLOWPOKE Research Reactor. A 2 MW prototype for the commercial unit is now being tested at the Whiteshell Nuclear Research Establishment in Manitoba. With capital costs of $7 million (Canadian), unit energy costs are projected to be $0.02/kWh for a 10 MW unit operating in a heating grid over a 30-year period. By keeping the reactor power low and the water temperature below 100 degrees C, much of the complexity of the large nuclear power plants can be avoided, thus allowing these small, safe nuclear heating systems to be economically viable

  14. Fuzzy comprehensive evaluation of district heating systems

    International Nuclear Information System (INIS)

    Wei Bing; Wang Songling; Li Li

    2010-01-01

    Selecting the optimal type of district heating (DH) system is of great importance because different heating systems have different levels of efficiency, which will impact the system economics, environment and energy use. In this study, seven DH systems were analysed and evaluated by the fuzzy comprehensive evaluation method. The dimensionless number-goodness was introduced into the calculation, the economics, environment and energy technology factors were considered synthetically, and the final goodness values were obtained. The results show that if only one of the economics, environment or energy technology factors are considered, different heating systems have different goodness values. When all three factors were taken into account, the final ranking of goodness values was: combined heating and power>gas-fired boiler>water-source heat pump>coal-fired boiler>ground-source heat pump>solar-energy heat pump>oil-fired boiler. The combined heating and power system is the best choice from all seven systems; the gas-fired boiler system is the best of the three boiler systems for heating purpose; and the water-source heat pump is the best of the three heat pump systems for heating and cooling.

  15. Fault diagnosis methods for district heating substations

    Energy Technology Data Exchange (ETDEWEB)

    Pakanen, J.; Hyvaerinen, J.; Kuismin, J.; Ahonen, M. [VTT Building Technology, Espoo (Finland). Building Physics, Building Services and Fire Technology

    1996-12-31

    A district heating substation is a demanding process for fault diagnosis. The process is nonlinear, load conditions of the district heating network change unpredictably and standard instrumentation is designed only for control and local monitoring purposes, not for automated diagnosis. Extra instrumentation means additional cost, which is usually not acceptable to consumers. That is why all conventional methods are not applicable in this environment. The paper presents five different approaches to fault diagnosis. While developing the methods, various kinds of pragmatic aspects and robustness had to be considered in order to achieve practical solutions. The presented methods are: classification of faults using performance indexing, static and physical modelling of process equipment, energy balance of the process, interactive fault tree reasoning and statistical tests. The methods are applied to a control valve, a heat excharger, a mud separating device and the whole process. The developed methods are verified in practice using simulation, simulation or field tests. (orig.) (25 refs.)

  16. THERMOS, district central heating nuclear reactors

    International Nuclear Information System (INIS)

    Patarin, L.

    1981-02-01

    In order to expand the penetration of uranium in the national energy balance sheet, the C.E.A. has been studying nuclear reactors for several years now, that are capable of providing heat at favourable economic conditions. In this paper the THERMOS model is introduced. After showing the attraction of direct town heating by nuclear energy, the author describes the THERMOS project, defines the potential market, notably in France, and applies the lay-out study to the Grenoble Nuclear Study Centre site with district communal heating in mind. The economic aspects of the scheme are briefly mentioned [fr

  17. Improving urban district heating systems and assessing the efficiency of the energy usage therein

    Science.gov (United States)

    Orlov, M. E.; Sharapov, V. I.

    2017-11-01

    The report describes issues in connection with improving urban district heating systems from combined heat power plants (CHPs), to propose the ways for improving the reliability and the efficiency of the energy usage (often referred to as “energy efficiency”) in such systems. The main direction of such urban district heating systems improvement suggests transition to combined heating systems that include structural elements of both centralized and decentralized systems. Such systems provide the basic part of thermal power via highly efficient methods for extracting thermal power plants turbines steam, while peak loads are covered by decentralized peak thermal power sources to be mounted at consumers’ locations, with the peak sources being also reserve thermal power sources. The methodology was developed for assessing energy efficiency of the combined district heating systems, implemented as a computer software product capable of comparatively calculating saving on reference fuel for the system.

  18. Heat Driven Cooling in District Energy Systems; Vaermedriven Kyla

    Energy Technology Data Exchange (ETDEWEB)

    Rydstrand, Magnus; Martin, Viktoria; Westermark, Mats [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Chemical Engineering and Technology

    2004-07-01

    high costs. However heat sinks are unavoidable from a system perspective and there are potential cost savings since a low-pressure steam turbines will not be required if heat driven cooling is implemented. The fuel utilization for some technologies (not necessarily the best technology) was evaluated in two different scenarios: 1) with electricity production from coal; and 2) with electricity production from natural gas. It is shown in the scenarios that the heat driven cooling technologies give lower fuel consumption as compared producing electricity as an intermediate product before cooling is produced. Further it should be noted that electricity is produced, not consumed, if heat is used directly for the production of cooling. We claim that cost effective solutions for district heat driven chillers and/or combined production of electricity and district cooling can be found in all climates with high enough density of heating and cooling demands. It was found that district heat driven chillers can be very energy efficient in warm and humid climates since desiccant systems are an effective way of handling latent cooling loads. In dry climates, with low latent loads, water distributed cooling has a large potential and absorption cooling will give high fuel utilization seen from a system perspective. In climates where water shortage is a problem it is possible that the temperature lift of the conventional absorption chiller has to be increased in order to be able to use dry cooling towers. The temperature lift can be increased by changing the chiller design or by using a different working pair. Heat driven cooling can be integrated into an energy system in different ways. In USA and Japan, district heating is not well developed. Instead small, distributed combined heat and power (CHP) plants with high exhaust temperatures are widespread. Cooling is often produced, in these regions, through absorption cooling (using heat from CHP) or compression chillers depending on

  19. Optimizing the Heat Exchanger Network of a Steam Reforming System

    DEFF Research Database (Denmark)

    Nielsen, Mads Pagh; Korsgaard, Anders Risum; Kær, Søren Knudsen

    2004-01-01

    Proton Exchange Membrane (PEM) based combined heat and power production systems are highly integrated energy systems. They may include a hydrogen production system and fuel cell stacks along with post combustion units optionally coupled with gas turbines. The considered system is based on a natural...... stationary numerical system model was used and process integration techniques for optimizing the heat exchanger network for the reforming unit are proposed. Objective is to minimize the system cost. Keywords: Fuel cells; Steam Reforming; Heat Exchanger Network (HEN) Synthesis; MINLP....... gas steam reformer along with gas purification reactors to generate clean hydrogen suited for a PEM stack. The temperatures in the various reactors in the fuel processing system vary from around 1000°C to the stack temperature at 80°C. Furthermore, external heating must be supplied to the endothermic...

  20. A Feasibility Study on District Heating and Cooling Business Using Urban Waste Heat

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Joon; Choi, Byoung Youn; Lee, Kyoung Ho; Lee, Jae Bong [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Yoo, Jae In; Yoon, Jae Ho; Oh, Myung Do; Park, Moon Su; Kang, Han Kee; Yoo, Kyeoung Hoon; Bak, Jong Heon; Kim, Sun Chang; Park, Heong Kee; Bae, Tae Sik [Korea Academy of Industrial Technology, Seoul (Korea, Republic of)

    1996-12-31

    Investigation of papers related to waste heat utilization using heat pump. Estimate of various kinds of urban waste heat in korea. Investigation and study on optimal control of district heating and cooling system. Prediction of energy saving and environmental benefits when the urban waste heat will be used as heat source and sink of heat pump for district heating and cooling. Estimation of economic feasibility on district heating and cooling project utilizing urban waste heat. (author). 51 refs., figs

  1. Design of biomass district heating systems

    International Nuclear Information System (INIS)

    Vallios, Ioannis; Tsoutsos, Theocharis; Papadakis, George

    2009-01-01

    The biomass exploitation takes advantage of the agricultural, forest, and manure residues and in extent, urban and industrial wastes, which under controlled burning conditions, can generate heat and electricity, with limited environmental impacts. Biomass can - significantly - contribute in the energy supplying system, if the engineers will adopt the necessary design changes to the traditional systems and become more familiar with the design details of the biomass heating systems. The aim of this paper is to present a methodology of the design of biomass district heating systems taking into consideration the optimum design of building structure and urban settlement around the plant. The essential energy parameters are presented for the size calculations of a biomass burning-district heating system, as well as for the environmental (i.e. Greenhouse Gas Emissions) and economic evaluation (i.e. selectivity and viability of the relevant investment). Emphasis has been placed upon the technical parameters of the biomass system, the economic details of the boiler, the heating distribution network, the heat exchanger and the Greenhouse Gas Emissions

  2. Distributed heat generation in a district heating system

    OpenAIRE

    Lennermo, Gunnar; Lauenberg, Patrick

    2016-01-01

    District heating (OH) systems need to be improved  regarding integration  of decentralised  heat generation. Micro production, prosumers and smart grids are terms becoming more and more common  in  connection  to  the  power  grid.  Concerning district  heating,  the  development  is slower, although improving. Today there are a number of such decentralised units for heat generation,  mainly  solar,  that have been partly evaluated.  Previous  studies  have shown  that there is a need to deve...

  3. District heating service connections. Technical recommendations. 4. ed. Hausanschluesse an Fernwaermenetze. Technische Richtlinien

    Energy Technology Data Exchange (ETDEWEB)

    1986-01-01

    The fourth edition of the 'Technical regulations - district heating service connections' constitutes a completely revised version answering to the considerable developments and changes the house service sector experienced between 1975 and 1985. Analyses and practical experiences have proved to show that precision thermostats which, depending on the mode of lines and layout of the service system allow to spare central temperature control systems, still have a decisive influence on the design of district heating service stations. The revised chapter on steam line service connections focuses on problems concerning the metering of condensates and the connection of secondary water heating networks to steam lines. The reader finds an updated selection of diagrams as well as a revised appendix listing the AGFW codes of practice and recommendations, relevant DIN standards and relevant VDE/VDI recommendations.

  4. Corrosion Rate Monitoring in District Heating Systems

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Nielsen, Lars Vendelbo; Andersen, A.

    2005-01-01

    be applicable, and if on-line monitoring could improve the quality control. Water quality monitoring was applied as well as corrosion rate monitoring with linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), electrical resistance (ER) technique, mass loss and a crevice corrosion......Quality control in district heating systems to keep uniform corrosion rates low and localized corrosion minimal is based on water quality control. Side-stream units equipped with carbon steel probes for online monitoring were mounted in district heating plants to investigate which techniques would...... cell for localized corrosion risk estimation. Important variations in corrosion rate due to changes in make-up water quality were detected with the continuous monitoring provided by ER and crevice cell, while LPR gave unreliable corrosion rates. The acquisition time of two-three days for EIS...

  5. District heating in energetic and environmental politics

    Energy Technology Data Exchange (ETDEWEB)

    di Riscaldamento Urbano, Associazione Italiana

    1989-05-01

    A review is made of what was said at the Third Bi-annual Convention (Reggio Emilia, 24-25/11/88) of AIRU (the Italian Association for District Heating). In general, the seven papers presented dealt with the following points: the technology of primary energy supply, thermal energy production, energy distribution to users, environmental engineering and socio-economic factors. Emphasis was given to the themes: district heating in Italy within the framework of the 1988 National Energy Plan and the impact on energy marketing due to the future free trade system planned for the E.E.C. in 1992. A critical analysis is made of: forecasts of primary energy demand for the year 2000, plans for the reduction of dependency on foreign supplied petroleum, the promotion of the increased use of natural gas and methane and overall energy conservation measures as called for by the National Energy Plan.

  6. Application of an intermediate LWR for electricity production and hot-water district heating

    International Nuclear Information System (INIS)

    1983-05-01

    The objective of the study is to evaluate the technical and economic feasibility of a 400 MWe Consolidated Nuclear Steam System (CNSS) for supplying district heat to the Minneapolis/St. Paul area. A total of three CNSS reactor sites, located various distances from the Minneapolis-St. Paul area load center, are evaluated. The distance from the load center is determined by the credited safety features of the plant design. Each site is also evaluated for three different hot water supply/return temperatures providing a total of nine CNSS study cases. The cost of district heat delivered to the load center is determined for each case

  7. Procedures for selecting and buying district heating equipment. Sofia district heating. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-11-01

    The aim of this Final Report, prepared for the project `Procedures for Selecting and Buying DistRict Heating Equipment - Sofia District Heating Company`, is to establish an overview of the activities accomplished, the outputs delivered and the general experience gained as a result of the project. The main objective of the project is to enable Sofia District Heating Company to prepare specifications and tender documents, identify possible suppliers, evaluate offers, etc. in connection with purchase of district heating equipment. This objective has been reached by using rehabilitation of sub-stations as an example requested by Sofia DH. The project was originally planned to be finalized end of 1995, but due to the extensions of the scope of work, the project has been prolonged until end 1997. The following main activities were accomplished: Preparation of a detailed work plan; Collection of background information; Discussion and advice about technical specifications and tender documents for sub-station rehabilitation; Input to terms of reference for a master plan study; Input to technical specification for heat meters; Collection of ideas for topics and examples related to dissemination of information to consumers about matters related to district heating consumption. (EG)

  8. State and development prospects of district heating in the FRG

    International Nuclear Information System (INIS)

    Buch, A.

    1975-12-01

    The study outlines the state of district heating, investigates the preconditions of its increased application and determines the thus obtainable saving in energy consumption. The heat consumption in homes, the energy use and the types of heating for room heating and hot water supply, the covering of the demand for district heating, design of a district heating supply, the regional planning and the production costs of district heating are individually considered. The results are shown clearly in tables, maps and and graphs. (HR/LH) [de

  9. Innovative system for delivery of low temperature district heating

    OpenAIRE

    Ianakiev, A; Cui, JM; Garbett, S; Filer, A

    2017-01-01

    An innovative low temperature district heating (LTDH) local network is developed in Nottingham, supported by the REMOURBAN project, part of the H2020 Smart City and Community Lighthouse scheme. It was proposed that a branch emanating from the return pipe of the existing district heating system in Nottingham would be created to use low temperature heating for the first time on such scale in the UK. The development is aimed to extract unused heat from existing district heating system and to mak...

  10. Interfacial heat transfer in countercurrent flows of steam and water

    International Nuclear Information System (INIS)

    Megahed, M.M.

    1987-04-01

    A study was conducted to examine the departure from equilibrium conditions with respect to direct contact condensation. A simple analytical model, which used an equilibrium factor, K, was derived. The model was structured to represent the physical dimensions of a nuclear reactor downcomer annulus, water subcooling, wall temperature, and water flow rate. In a two step process the model was first used to isolate the average interfacial heat transfer coefficient from vertical countercurrent steam/water data of Cook et al., with the aid of a Stanton number correlation. In the second step the model was assessed by regeneration of measured steam flow rates in the experiments by Cook et al., and an additional experiment of Kim. This report documents the analytical model, the derived Stanton number correlation, and the comparison of the calculated and measured steam flow rates by which the accuracy of the model was assessed

  11. Design of serially connected district heating heat pumps utilising a geothermal heat source

    DEFF Research Database (Denmark)

    Jensen, Jonas Kjær; Ommen, Torben Schmidt; Markussen, Wiebke Brix

    2017-01-01

    The design of two heat pumps (HP), connected in series, was investigated for operation in the district heating (DH) network of the Greater Copenhagen area, Denmark. The installation was dimensioned to supply 7.2 MW of heat at a temperature of 85 °C. The heat pumps utilise a geothermal heat source...

  12. Application of Predictive Control in District Heating Systems

    DEFF Research Database (Denmark)

    Palsson, Olafur Petur; Madsen, Henrik; Søgaard, Henning Tangen

    1993-01-01

    In district heating systems, and in particular if the heat production cakes place at a combined heat and power (CHP) plant, a reasonable control strategy is to keep the supply temperature from the district heating plant as low as possible. However, the control is subject to some restrictions, for...

  13. Rod Bundle Heat Transfer: Steady-State Steam Cooling Experiments

    International Nuclear Information System (INIS)

    Spring, J.P.; McLaughlin, D.M.

    2006-01-01

    Through the joint efforts of the Pennsylvania State University and the United States Nuclear Regulatory Commission, an experimental rod bundle heat transfer (RBHT) facility was designed and built. The rod bundle consists of a 7 x 7 square pitch array with spacer grids and geometry similar to that found in a modern pressurized water reactor. From this facility, a series of steady-state steam cooling experiments were performed. The bundle inlet Reynolds number was varied from 1 400 to 30 000 over a pressure range from 1.36 to 4 bars (20 to 60 psia). The bundle inlet steam temperature was controlled to be at saturation for the specified pressure and the fluid exit temperature exceeded 550 deg. C in the highest power tests. One important quantity of interest is the local convective heat transfer coefficient defined in terms of the local bulk mean temperature of the flow, local wall temperature, and heat flux. Steam temperatures were measured at the center of selected subchannels along the length of the bundle by traversing miniaturized thermocouples. Using an analogy between momentum and energy transport, a method was developed for relating the local subchannel centerline temperature measurement to the local bulk mean temperature. Wall temperatures were measured using internal thermocouples strategically placed along the length of each rod and the local wall heat flux was obtained from an inverse conduction program. The local heat transfer coefficient was calculated from the data at each rod thermocouple location. The local heat transfer coefficients calculated for locations where the flow was fully developed were compared against several published correlations. The Weisman and El-Genk correlations were found to agree best with the RBHT steam cooling data, especially over the range of turbulent Reynolds numbers. The effect of spacer grids on the heat transfer enhancement was also determined from instrumentation placed downstream of the spacer grid locations. The local

  14. Mapping of potential heat sources for heat pumps for district heating in Denmark

    International Nuclear Information System (INIS)

    Lund, Rasmus; Persson, Urban

    2016-01-01

    The ambitious policy in Denmark on having a 100% renewable energy supply in 2050 requires radical changes to the energy systems to avoid an extensive and unsustainable use of biomass resources. Currently, wind power is being expanded and the increasing supply of electricity is slowly pushing the CHP (combined heat and power) plants out of operation, reducing the energy efficiency of the DH (district heating) supply. Here, large heat pumps for district heating is a frequently mentioned solution as a flexible demand for electricity and an energy efficient heat producer. The idea is to make heat pump use a low temperature waste or ambient heat source, but it has so far been very unclear which heat sources are actually available for this purpose. In this study eight categories of heat sources are analysed for the case of Denmark and included in a detailed spatial analysis where the identified heat sources are put in relation to the district heating areas and the corresponding demands. The analysis shows that potential heat sources are present near almost all district heating areas and that sea water most likely will have to play a substantial role as a heat source in future energy systems in Denmark. - Highlights: • The availability of heat sources for heat pumps in Denmark are mapped and quantified. • A novel methodology for assessment of low temperature industrial excess heat is presented. • There are heat sources available for 99% of district heating networks in Denmark. • The concentration of heat sources is generally bigger around bigger cities than smaller. • Ambient temperature heat sources will be more needed in district heating of big cities.

  15. Kaliningrad regional district heating network 2004-2006. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-06-15

    This report concerns: Kaliningrad Regional District Heating Network project which was implemented from 2004 to 2006. The task of the project was to establish and operate an association for district heating companies in the region in order to transfer and distribute district heating know-how to the sector and through activities strengthen the sector. The long term aim was to contribute to establishment of an association to continue as a real association for the heat supply companies in the region. (au)

  16. Steps towards modern trends in district heating

    Directory of Open Access Journals (Sweden)

    Vasek Lubomir

    2017-01-01

    Full Text Available This paper focuses on new trends in district heating a cooling (DHC area and algorithms allowing incorporating new technologies and performing optimal control. Classical district heating usually means huge source (as heating plant and set of pipes which transfer heat energy through a medium, mostly water, across whole town and chilled water is returning back to the plant. Let’s imagine a modern city where buildings are consuming only a fraction of the energy contrary to what buildings required in the past. And especially during sunny or windy days, they have energy to spare. Around of such modern city is not only the one big heating plant, but perhaps solar and wind farms, waste incinerators, industrial companies with energy surpluses. Simply in this modern city are dozens, perhaps hundreds of small energy producers that share pipe network or at least part of it. In such a district energy system, production planning is more difficult. And not only production, modern houses with minimal heat loss and data connections also allow to plan consumption more effectively. The aim is to achieve the best solution evaluated by the objective function, usually determined by minimizing the production and distribution costs and providing meets the needs of energy consumers. The method presented in this paper is based on a simulation using the proposed holonic distributed model. This model also introduces the idea of general prosumers strategy, where all active elements within the modern DHC system are represented by prosumer objects. The prosumers are perceived as objects able to actively participate in the planning and realization of the production and consumption of energy. It is assumed that the general behaviour of the object in DHC is the same, no matter how they differ in size and design. Thus, all the objects are defined by two characteristics - the ability to produce and consume. The model based on this basic principle, of course, with the most

  17. Measurement of condensation heat transfer coefficients in a steam chamber using a variable conductance heat pipe

    International Nuclear Information System (INIS)

    Robinson, J.A.; Windebank, S.R.

    1988-01-01

    Condensation heat transfer coefficients have been measured in a pressurised chamber containing a mixture of saturated steam and air. They were determined as a function of the air-steam ratio in nominally stagnant conditions. The effect of pressure is assessed and preliminary measurements with a forced convective component of velocity are presented. A novel measurement technique was adopted, namely to use a vertical heat pipe whose conductance could easily be varied. It transported heat from an evaporator located inside the chamber to a condenser section outside, at which the heat flow was measured. Heat flux at the evaporator could then be determined and a condensation heat transfer coefficient derived. The range of coefficients covered was from 150 W/m 2 0 K at high air-steam ratios to 20,000 W/m 2 0 K in pure steam. Results show that increasing either total pressure or velocity enhances condensation heat transfer over the range of air/steam ratios considered. (author)

  18. Industrial waste heat utilization for low temperature district heating

    International Nuclear Information System (INIS)

    Fang, Hao; Xia, Jianjun; Zhu, Kan; Su, Yingbo; Jiang, Yi

    2013-01-01

    Large quantities of low grade waste heat are discharged into the environment, mostly via water evaporation, during industrial processes. Putting this industrial waste heat to productive use can reduce fossil fuel usage as well as CO 2 emissions and water dissipation. The purpose of this paper is to propose a holistic approach to the integrated and efficient utilization of low-grade industrial waste heat. Recovering industrial waste heat for use in district heating (DH) can increase the efficiency of the industrial sector and the DH system, in a cost-efficient way defined by the index of investment vs. carbon reduction (ICR). Furthermore, low temperature DH network greatly benefits the recovery rate of industrial waste heat. Based on data analysis and in-situ investigations, this paper discusses the potential for the implementation of such an approach in northern China, where conventional heat sources for DH are insufficient. The universal design approach to industrial-waste-heat based DH is proposed. Through a demonstration project, this approach is introduced in detail. This study finds three advantages to this approach: (1) improvement of the thermal energy efficiency of industrial factories; (2) more cost-efficient than the traditional heating mode; and (3) CO 2 and pollutant emission reduction as well as water conservation. -- Highlights: •We review situation of industrial waste heat recovery with a global perspective. •We present a way to analyze the potential to utilize industrial waste heat for DH. •Northern China has huge potential for using low-grade industrial waste heat for DH. •A demonstration project is introduced using the universal approach we propose. •It proves huge benefits for factories, heat-supply companies and the society

  19. New waste heat district heating system with combined heat and power based on absorption heat exchange cycle in China

    International Nuclear Information System (INIS)

    Sun Fangtian; Fu Lin; Zhang Shigang; Sun Jian

    2012-01-01

    A new waste heat district heating system with combined heat and power based on absorption heat exchange cycle (DHAC) was developed to increase the heating capacity of combined heat and power (CHP) through waste heat recovery, and enhance heat transmission capacity of the existing primary side district heating network through decreasing return water temperature by new type absorption heat exchanger (AHE). The DHAC system and a conventional district heating system based on CHP (CDH) were analyzed in terms of both thermodynamics and economics. Compared to CDH, the DHAC increased heating capacity by 31% and increased heat transmission capacity of the existing primary side district heating network by 75%. The results showed that the exergetic efficiency of DHAC was 10.41% higher and the product exergy monetary cost was 36.6¥/GJ less than a CHD. DHAC is an effective way to increase thermal utilization factor of CHP, and to reduce district heating cost. - Highlights: ► Absorption heat pumps are used to recover waste heat in CHP. ► Absorption heat exchanger can reduce exergy loss in the heat transfer process. ► New waste heat heating system (DHAC) can increase heating capacity of CHP by 31%. ► DHAC can enhance heat transmission capacity of the primary pipe network by 75%. ► DHAC system has the higher exergetic efficiency and the better economic benefit.

  20. District heating in case of power failure

    International Nuclear Information System (INIS)

    Lauenburg, P.; Johansson, P.-O.; Wollerstrand, J.

    2010-01-01

    Power failures in combination with harsh weather conditions during recent years have led to an increased focus on a safe energy supply to our society. Many vital functions are dependent on electricity; e.g., lighting, telephony, medical equipment, lifts, alarm systems, payment, pumps for town's water and, perhaps the most critical of all, heating systems. In Sweden, district heating (DH) is the most common type of heating for buildings in town centres. Therefore, it is of great interest to investigate what happens in DH systems during a power failure. The present study shows that, by maintaining the DH production as well as the operation of the DH network, possibilities to supply connected buildings with space heat are surprisingly good. This is due to the fact that natural circulation will most often take place in radiator systems. In Sweden, and in many other countries, so-called indirect connection (heat supply across heat exchangers) of DH substations is applied. If a DH network operation can be maintained during a power failure, DH water will continue to pass the radiator system's heat exchanger (HEX), provided that the control valve does not close. The radiator circulation pump will stop, causing the radiator water to attain a relatively high temperature in the HEX, which promotes a natural circulation in the hydronic heating system, due to an increased water density differential at different temperatures. Several field tests and computer simulations have been performed and have displayed that almost all buildings can achieve a space heat supply corresponding to 40-80% of the amount prior to the interruption. A sufficient heat load in the DH network can be vital in certain cases: e.g., for 'island-operation' of an electric power plant to be performed during a power failure. Furthermore, for many combined heat and power stations, a requirement involves that the DH network continues to provide a heat sink when no other cooling is available. Based on the

  1. Britain stays cool on district heating

    Energy Technology Data Exchange (ETDEWEB)

    Jones, G

    1982-04-08

    Britain's wealth of energy sources has kept interest in the energy conservation potential of combined heat and power (CHP) and district heating (DH) at a low level. An active lobby for CHP/DH continues to argue against formidable odds. The Marshall group set up in the early days of the oil crisis reported on several strategies for CHP/DH and proposed technologies already proven in other European countries. The economics of abundant natural gas and coal, however, precludes commercial interest until energy prices reach higher levels. The lobbyists point out that this could occur within a short time, and local governments would do well to examine the lead-city concept for application on a national level. The present government's preference for the private sector pursuing development beyond the feasibility-study stage could make CHP/DH more of a political issue as unemployment increases. (DCK)

  2. Customer perspectives on district heating price models

    Directory of Open Access Journals (Sweden)

    Kerstin Sernhed

    2017-01-01

    Full Text Available In Sweden there has been a move towards more cost reflective price models for district heating in order to reduce economic risks that comes with variable heat demand and high shares of fixed assets. The keywords in the new price models are higher shares of fixed cost, seasonal energy prices and charging for capacity. Also components that are meant to serve as incentives to affect behaviour are introduced, for example peak load components and flow components. In this study customer responses to these more complex price models have been investigated through focus group interviews and through interviews with companies that have changed their price models. The results show that several important customer requirements are suffering with the new price models. The most important ones are when energy savings do not provide financial savings, when costs are hard to predict and are perceived to be out of control.

  3. Demand side management for smart district heating

    DEFF Research Database (Denmark)

    Big, Oovidiu; Li, Hongwei; Svendsen, Svend

    2016-01-01

    between 25% and 35%. By making the light renovation, the heating system needs a minimum supply water temperature of 58ºC in order to cover the thermal comfort. Through extensive renovation, the supply water temperature could be reduced to 50ºC which makes it possible to transform the District Heating...... Temperature into Low Temperature. The building time constant for the extensive renovation is 86 hours which is double than a light building renovation and 53 hours higher than a non-renovated building. In the end of the paper is developed a formula which has the purpose to validate the results of virtual...... simulations. The relative percentage difference between the theoretical calculation and the virtual simulation results are between 2.5% and 17.5%....

  4. Influencing Swedish homeowners to adopt district heating system

    Energy Technology Data Exchange (ETDEWEB)

    Mahapatra, Krushna; Gustavsson, Leif [Ecotechnology, Mid Sweden University, Akademigatan 1, 831 25 Oestersund (Sweden)

    2009-02-15

    Improved energy efficiency and greenhouse gas mitigation could be achieved by replacing resistance heaters with district heating system. In 2005, only about 8% of the Swedish detached houses had district heating system. The expansion of such systems largely depends on homeowners' adoption decisions. And, to motivate homeowners to adopt district heating, it is essential to understand their decision-making process. In this context, in June 2005 we carried out a questionnaire survey of about 700 homeowners who lived in the city of Oestersund in houses with resistance heaters (baseline survey). About 84% of the respondents did not intend to install a new heating system. Since then these homeowners were influenced by (a) an investment subsidy by the Swedish government to replace resistance heaters with district heating, a brine/water-based heat pump, or a biomass-based heating system and (b) a marketing campaign by the municipality-owned district heating company. This paper analyses how these two measures influenced about 78% of the homeowners to adopt the district heating system. For this purpose we carried out a follow-up survey of the same homeowners in December 2006 (resurvey). Results showed that the investment subsidy and the marketing campaign created a need among the homeowners to adopt a new heating system. The marketing campaign was successful in motivating them to adopt the district heating system. The marketing strategy by the district heating company corresponds to the results obtained in the baseline survey. (author)

  5. Challenges in Smart Low-Temperature District Heating Development

    DEFF Research Database (Denmark)

    Li, Hongwei; Wang, Stephen Jia

    2014-01-01

    Previous research and development shows that low temperature district heating (LTDH) system is economic feasible for low energy buildings and buildings at sparse areas. Coupling with reduced network temperature and well-designed district heating (DH) networks, LTDH can reduce network heat loss by...

  6. Influencing Swedish homeowners to adopt district heating system

    Energy Technology Data Exchange (ETDEWEB)

    Mahapatra, Krushna; Gustavsson, Leif [Ecotechnology, Mid Sweden University, Akademigatan 1, 831 25 Oestersund (Sweden)

    2009-02-15

    Improved energy efficiency and greenhouse gas mitigation could be achieved by replacing resistance heaters with district heating system. In 2005, only about 8% of the Swedish detached houses had district heating system. The expansion of such systems largely depends on homeowners' adoption decisions. And, to motivate homeowners to adopt district heating, it is essential to understand their decision-making process. In this context, in June 2005 we carried out a questionnaire survey of about 700 homeowners who lived in the city of Oestersund in houses with resistance heaters (baseline survey). About 84% of the respondents did not intend to install a new heating system. Since then these homeowners were influenced by (a) an investment subsidy by the Swedish government to replace resistance heaters with district heating, a brine/water-based heat pump, or a biomass-based heating system and (b) a marketing campaign by the municipality-owned district heating company. This paper analyses how these two measures influenced about 78% of the homeowners to adopt the district heating system. For this purpose we carried out a follow-up survey of the same homeowners in December 2006 (resurvey). Results showed that the investment subsidy and the marketing campaign created a need among the homeowners to adopt a new heating system. The marketing campaign was successful in motivating them to adopt the district heating system. The marketing strategy by the district heating company corresponds to the results obtained in the baseline survey. (author)

  7. Influencing Swedish homeowners to adopt district heating system

    International Nuclear Information System (INIS)

    Mahapatra, Krushna; Gustavsson, Leif

    2009-01-01

    Improved energy efficiency and greenhouse gas mitigation could be achieved by replacing resistance heaters with district heating system. In 2005, only about 8% of the Swedish detached houses had district heating system. The expansion of such systems largely depends on homeowners' adoption decisions. And, to motivate homeowners to adopt district heating, it is essential to understand their decision-making process. In this context, in June 2005 we carried out a questionnaire survey of about 700 homeowners who lived in the city of Ostersund in houses with resistance heaters (baseline survey). About 84% of the respondents did not intend to install a new heating system. Since then these homeowners were influenced by (a) an investment subsidy by the Swedish government to replace resistance heaters with district heating, a brine/water-based heat pump, or a biomass-based heating system and (b) a marketing campaign by the municipality-owned district heating company. This paper analyses how these two measures influenced about 78% of the homeowners to adopt the district heating system. For this purpose we carried out a follow-up survey of the same homeowners in December 2006 (resurvey). Results showed that the investment subsidy and the marketing campaign created a need among the homeowners to adopt a new heating system. The marketing campaign was successful in motivating them to adopt the district heating system. The marketing strategy by the district heating company corresponds to the results obtained in the baseline survey

  8. A study of a small nuclear power plant system for district heating

    International Nuclear Information System (INIS)

    Imamura, Mitsuru; Sato, Kotaro; Narabayashi, Tadashi; Shimazu, Yoichiro; Tsuji, Masashi

    2008-01-01

    We have studied nuclear power plant for district heating. Already some towns and villages in Hokkaido have requested small reactor for district heating. Using existing technology allows us to shorten development period and to keep a lid on development cost. We decided to develop new reactor based on 'MUTSU' reactor technology. 'MUTSU' had already proved its safety. And 'MUTSU' reactor was boron free reactor. It allows plant system to become more compact and simple. And load following capability by core reactivity become bigger. It means to reduce control rod movement. It leads to dependability enhancement. We calculated burn-up calculation of erbium addition fuel. In the result the core life became about 10 years. In the district heating system, there are not only district heating but also snow melting with warm water. It uses steam condenser's heat, which are only discharged now. This small plant has passive safety system. It is natural cooling of containment vessel. In case of loss of coolant accident, decay heat can remove by natural convection air cooling after 6 hours. Decay heat within 6 hours can remove by evaporative heat transfer of pool on containment vessel. (author)

  9. HTCC - a heat transfer model for gas-steam mixtures

    International Nuclear Information System (INIS)

    Papadimitriou, P.

    1983-01-01

    The mathematical model HTCC (Heat Transfer Coefficient in Containment) has been developed for RALOC after a loss-of-coolant accident in order to determine the local heat transfer coefficients for transfer between the containment atmosphere and the walls of the reactor building. The model considers the current values of room and wall temperature, the concentration of steam and non-condensible gases, geometry data and those of fluid dynamics together with thermodynamic parameters and from these determines the heat transfer mechanisms due to convection, radiation and condensation. The HTCC is implemented in the RALOC program. Comparative analyses of computed temperature profiles, for HEDL Standard problems A and B on hydrogen distribution, and of computed temperature profiles determined during the heat-up phase in the CSE-A5 experiment show a good agreement with experimental data. (orig.) [de

  10. Method for Calculation of Steam-Compression Heat Transformers

    Directory of Open Access Journals (Sweden)

    S. V. Zditovetckaya

    2012-01-01

    Full Text Available The paper considers a method for joint numerical analysis of cycle parameters and heatex-change equipment of steam-compression heat transformer contour that takes into account a non-stationary operational mode and irreversible losses in devices and pipeline contour. The method has been realized in the form of the software package and can be used while making design or selection of a heat transformer with due account of a coolant and actual equipment being included in its structure.The paper presents investigation results revealing influence of pressure loss in an evaporator and a condenser from the side of the coolant caused by a friction and local resistance on power efficiency of the heat transformer which is operating in the mode of refrigerating and heating installation and a thermal pump. Actually obtained operational parameters of the thermal pump in the nominal and off-design operatinal modes depend on the structure of the concrete contour equipment.

  11. Local business models for district heat production; Kaukolaemmoen paikalliset liiketoimintamallit

    Energy Technology Data Exchange (ETDEWEB)

    Hakala, L.; Pesola, A.; Vanhanen, J.

    2012-12-15

    Local district heating business, outside large urban centers, is a profitable business in Finland, which can be practiced with several different business models. In addition to the traditional, local district heating business, local district heat production can be also based on franchising business model, on integrated service model or on different types of cooperation models, either between a local district heat producer and industrial site providing surplus heat or between a local district heat producer and a larger district heating company. Locally available wood energy is currently utilized effectively in the traditional district heating business model, in which a local entrepreneur produces heat to consumers in the local area. The franchising model is a more advanced version of the traditional district heating entrepreneurship. In this model, franchisor funds part of the investments, as well as offers centralized maintenance and fuel supply, for example. In the integrated service model, the local district heat producer offers also energy efficiency services and other value-added services, which are based on either the local district heat suppliers or his partner's expertise. In the cooperation model with industrial site, the local district heating business is based on the utilization of the surplus heat from the industrial site. In some cases, profitable operating model approach may be a district heating company outsourcing operations of one or more heating plants to a local entrepreneur. It can be concluded that all business models for district heat production (traditional district heat business model, franchising, integrated service model, cooperative model) discussed in this report can be profitable in Finnish conditions, as well for the local heat producer as for the municipality - and, above all, they produce cost-competitive heat for the end-user. All the models were seen as viable and interesting and having possibilities for expansion Finland

  12. Heat transfer efficient thermal energy storage for steam generation

    International Nuclear Information System (INIS)

    Adinberg, R.; Zvegilsky, D.; Epstein, M.

    2010-01-01

    A novel reflux heat transfer storage (RHTS) concept for producing high-temperature superheated steam in the temperature range 350-400 deg. C was developed and tested. The thermal storage medium is a metallic substance, Zinc-Tin alloy, which serves as the phase change material (PCM). A high-temperature heat transfer fluid (HTF) is added to the storage medium in order to enhance heat exchange within the storage system, which comprises PCM units and the associated heat exchangers serving for charging and discharging the storage. The applied heat transfer mechanism is based on the HTF reflux created by a combined evaporation-condensation process. It was shown that a PCM with a fraction of 70 wt.% Zn in the alloy (Zn70Sn30) is optimal to attain a storage temperature of 370 deg. C, provided the heat source such as solar-produced steam or solar-heated synthetic oil has a temperature of about 400 deg. C (typical for the parabolic troughs technology). This PCM melts gradually between temperatures 200 and 370 deg. C preserving the latent heat of fusion, mainly of the Zn-component, that later, at the stage of heat discharge, will be available for producing steam. The thermal storage concept was experimentally studied using a lab scale apparatus that enabled investigating of storage materials (the PCM-HTF system) simultaneously with carrying out thermal performance measurements and observing heat transfer effects occurring in the system. The tests produced satisfactory results in terms of thermal stability and compatibility of the utilized storage materials, alloy Zn70Sn30 and the eutectic mixture of biphenyl and diphenyl oxide, up to a working temperature of 400 deg. C. Optional schemes for integrating the developed thermal storage into a solar thermal electric plant are discussed and evaluated considering a pilot scale solar plant with thermal power output of 12 MW. The storage should enable uninterrupted operation of solar thermal electric systems during additional hours

  13. Experimental study of heat transfer and pressure drop characteristics of air/water and air-steam/water heat exchange in a polymer compact heat exchanger

    NARCIS (Netherlands)

    Cheng, L.; Geld, van der C.W.M.

    2005-01-01

    Experiments of heat transfer and pressure drop in a polymer compact heat exchanger made of PolyVinyliDene-Fluoride were conducted under various conditions for air/water heat exchange and air-steam/water heat exchange, respectively. The overall heat transfer coefficients of air-steam/water heat

  14. Steam gasification of coal, project prototype plant nuclear process heat

    International Nuclear Information System (INIS)

    Heek, K.H. van

    1982-05-01

    This report describes the tasks, which Bergbau-Forschung has carried out in the field of steam gasification of coal in cooperation with partners and contractors during the reference phase of the project. On the basis of the status achieved to date it can be stated, that the mode of operation of the gas-generator developed including the direct feeding of caking high volatile coal is technically feasible. Moreover through-put can be improved by 65% at minimum by using catalysts. On the whole industrial application of steam gasification - WKV - using nuclear process heat stays attractive compared with other gasification processes. Not only coal is conserved but also the costs of the gas manufactured are favourable. As confirmed by recent economic calculations these are 20 to 25% lower. (orig.) [de

  15. Energy and exergy analysis of low temperature district heating network

    International Nuclear Information System (INIS)

    Li, Hongwei; Svendsen, Svend

    2012-01-01

    Low temperature district heating with reduced network supply and return temperature provides better match of the low quality building heating demand and the low quality heating supply from waste heat or renewable energy. In this paper, a hypothetical low temperature district heating network is designed to supply heating for 30 low energy detached residential houses. The network operational supply/return temperature is set as 55 °C/25 °C, which is in line with a pilot project carried out in Denmark. Two types of in-house substations are analyzed to supply the consumer domestic hot water demand. The space heating demand is supplied through floor heating in the bathroom and low temperature radiators in the rest of rooms. The network thermal and hydraulic conditions are simulated under steady state. A district heating network design and simulation code is developed to incorporate the network optimization procedure and the network simultaneous factor. Through the simulation, the overall system energy and exergy efficiencies are calculated and the exergy losses for the major district heating system components are identified. Based on the results, suggestions are given to further reduce the system energy/exergy losses and increase the quality match between the consumer heating demand and the district heating supply. -- Highlights: ► Exergy and energy analysis for low and medium temperature district heating systems. ► Different district heating network dimensioning methods are analyzed. ► Major exergy losses are identified in the district heating network and the in-house substations. ► Advantages to apply low temperature district heating are highlighted through exergy analysis. ► The influence of thermal by-pass on system exergy/energy performance is analyzed.

  16. Comparing studies for an optimization of steam-heated tube bundle heat exchangers

    International Nuclear Information System (INIS)

    Horn, M.

    1975-01-01

    The problems of designing an apparatus are to be shown by the example of the steam-heated tube bundle heat exchanger, and optimizations are to be carried through by relevant examples. From the results of the optimization, a set of apparatus types is to be derived where the dimensions of the shell and the heat pipes as well as the length of the tube bundle are to be determined by as few data as possible. (orig./TK) [de

  17. Gasification of coal with steam using heat from HTRs

    International Nuclear Information System (INIS)

    Juentgen, H.; Heek, K.H. van

    1975-01-01

    In existing coal gasification processes a substantial part of the coal is used to provide the heat for the reaction, for the generation and superheating of steam and for the production of oxygen. By using heat from HTRs to substitute this part, the coal is then completely used as raw material for gas production. This offers the following advantages compared with the existing processes: a saving of coal, less CO 2 emission and, in countries with high coal costs, lower gas production costs. A survey is given of the state of the project, discussing the first design of a commercial gasifier, the influence of the helium outlet temperature of the HTR, kinds of products, and the overall efficiency of the plant. The aim of the development is to demonstrate the use of heat from an HTR for full scale coal gasification, starting in 1985. (Auth.)

  18. Feasibility of a single-purpose reactor plant for district heating in Finland

    International Nuclear Information System (INIS)

    Tarjanne, R.; Vuori, S.; Eerikaeinen, L.; Saukkoriipi, L.

    A feasibility study of a single-purpose reactor for district heating is presented. The reactor chosen is of an ordinary pressurized water reactor type with a thermal output of 100 to 200 MW. Primary circuit steam generators employed in ordinary PWR's are replaced by water-water heat exchangers. For safety reasons an intermediate circuit separates the primary from the network water. The conditions of the district heating systems in Finland were taken into account, which led to the choice of an average temperature of 160 0 C for the reactor coolant and a pressure of 13.5 bar. This, coupled with minimal control requirements helped design a considerably simple reactor plant. On condition, the reactor satisfies the basic heat demand in a district heating system, the effective annual full-power operation time of the heating reactor is from 5000 h to 7000 h. Economic comparisons indicated that the heating reactor may be competitive if the operation period is of this order. As the reactor has to be sited near the heat consumption area for reasons of economy, the safety aspects are of major importance and may in themselves preclude the realization of the heating idea. (author)

  19. Pricing district heating by marginal cost

    International Nuclear Information System (INIS)

    Difs, Kristina; Trygg, Louise

    2009-01-01

    A vital measure for industries when redirecting the energy systems towards sustainability is conversion from electricity to district heating (DH). This conversion can be achieved for example, by replacing electrical heating with DH and compression cooling with heat-driven absorption cooling. Conversion to DH must, however, always be an economically attractive choice for an industry. In this paper the effects for industries and the local DH supplier are analysed when pricing DH by marginal cost in combination with industrial energy efficiency measures. Energy audits have shown that the analysed industries can reduce their annual electricity use by 30% and increase the use of DH by 56%. When marginal costs are applied as DH tariffs and the industrial energy efficiency measures are implemented, the industrial energy costs can be reduced by 17%. When implementing the industrial energy efficiency measures and also considering a utility investment in the local energy system, the local DH supplier has a potential to reduce the total energy system cost by 1.6 million EUR. Global carbon dioxide emissions can be reduced by 25,000 tonnes if the industrial energy efficiency measures are implemented and when coal-condensing power is assumed to be the marginal electricity source

  20. District heating systems' control for cost effective and environmentally compatible operation

    International Nuclear Information System (INIS)

    Balati, J.

    1999-01-01

    District heating systems are being developed in accordance with the growing of large European cities. These systems are formed by enlarging networks of heat distribution from heat sources to heat consumers and, simultaneously, by gradually connecting newly built heat sources. District heating control consists in optimum control of the output of heat sources and in control of heat distribution and consumption. The aim of the paper is to inform about the works in the field of creating a mathematical-physical model of extensive hot water and steam supply circle network and heat sources for the purpose of creating unconventional control algorithms for the complex control of the technological sequence ''heat production distribution- consumption''. For the optimum control algorithms the artificial intelligence methods are also utilised. The aim of the complex access to the solution of new control algorithms will be to decrease the cost of the consumed heat unit and increase environmental protection. The function of the Extensive Heating System District Heating System (DHS) is to ensure permanently the economically justified requirements of heat supply for all consumers with minimum cost per heat supply unit and with enhanced level of environmental protection. The requirements of heat consumers have to be in harmony with the requirements of the maximum possible economy of the whole DHS when adhering to the required qualitative parameters of supplied energy. Therefore, it offers the application of optimised control methods as artificial intelligence methods for the control of the operational circle of DHS heat networks. It is obvious that a higher level of DHS control is required from the technological, economic and ecological point of view. (author)

  1. Electromagnetic heating method to improve steam assisted gravity drainage

    Energy Technology Data Exchange (ETDEWEB)

    Koolman, M.; Huber, N.; Diehl, D.; Wacker, B. [Siemens AG, Munich (Germany)

    2008-10-15

    The in-situ recovery of heavy and highly viscous bitumen has become economically feasible with the use of steam assisted gravity drainage (SAGD). However, several challenges exist, such as the energy cost for production of bitumen; environmental concerns over the consumption of water; limited recovery of bitumen; shallowness of the reservoirs; and the propagation of steam chambers leading to limited recovery. This paper described an opportunity to improve the widely applied SAGD process for in-situ production of bitumen from oil sands deposits. The technical concept was directed at electromagnetic (EM-SAGD) heating methods assisting the process. The paper described a preliminary investigation that was conducted in order to confirm the feasibility of different solutions and evaluate aspects of energy efficiency and environmental impact. A comparison of electrical heating methods showed that the inductive method was the most reasonable in terms of technical and economical feasibility. The paper also discussed a small scale sandbox test to verify a three-dimensional simulation provided with two different simulation tools. The results of reservoir simulation were also presented. Last, the paper examined health and safety considerations. It was concluded that inductive heating provides an additional, easy to handle control parameter. The study showed that if the geometries of the inductors related to the producer wells were selected in a tailor-made manner, individual reservoir conditions could be handled by an optimized operating strategy. 4 refs., 3 tabs., 15 figs.

  2. Integrated multiscale simulation of combined heat and power based district heating system

    International Nuclear Information System (INIS)

    Li, Peifeng; Nord, Natasa; Ertesvåg, Ivar Ståle; Ge, Zhihua; Yang, Zhiping; Yang, Yongping

    2015-01-01

    Highlights: • Simulation of power plant, district heating network and heat users in detail and integrated. • Coupled calculation and analysis of the heat and pressure losses of the district heating network. • District heating is not preferable for very low heat load due to relatively high heat loss. • Lower design supply temperatures of the district heating network give higher system efficiency. - Abstract: Many studies have been carried out separately on combined heat and power and district heating. However, little work has been done considering the heat source, the district heating network and the heat users simultaneously, especially when it comes to the heating system with large-scale combined heat and power plant. For the purpose of energy conservation, it is very important to know well the system performance of the integrated heating system from the very primary fuel input to the terminal heat users. This paper set up a model of 300 MW electric power rated air-cooled combined heat and power plant using Ebsilon software, which was validated according to the design data from the turbine manufacturer. Then, the model of heating network and heat users were developed based on the fundamental theories of fluid mechanics and heat transfer. Finally the combined heat and power based district heating system was obtained and the system performances within multiscale scope of the system were analyzed using the developed Ebsilon model. Topics with regard to the heat loss, the pressure drop, the pump power consumption and the supply temperatures of the district heating network were discussed. Besides, the operational issues of the integrated system were also researched. Several useful conclusions were drawn. It was found that a lower design primary supply temperature of the district heating network would give a higher seasonal energy efficiency of the integrated system throughout the whole heating season. Moreover, it was not always right to relate low design

  3. An experimental investigation of the isochoric heat capacity of superheated steam and mixtures of superheated steam and hydrogen gas

    International Nuclear Information System (INIS)

    Nowak, E.S.; Chan, J.S.

    1975-01-01

    Measurements on the specific heat at constant volume of superheated steam and hydrogen gas mixtures at concentrations varying from 1.6 to 0.8 moles of water vapor per mole of hydrogen gas were made for temperatures ranging from 240 to 400 deg C. It was found that the experimental specific heat values of the mixtures are in good agreement with the ideal mixture values only near the saturation temperature of steam. The difference between the measured and the calculated ideal mixture values is a function of temperature, pressure and composition varying from about 11 to 24% at conditions far removed from the saturation temperature of steam. This indicates the heat of mixing is of significance in the steam-hydrogen system

  4. District Heating Expansion Potential with Low-Temperature and End-Use Heat Savings

    DEFF Research Database (Denmark)

    Nielsen, Steffen; Grundahl, Lars

    2018-01-01

    District heating has the potential to play a key role in the transition towards a renewable energy system. However, the development towards reduced heat demands threatens the feasibility of district heating. Despite this challenge, opportunity exists in the form of fourth generation district...... heating, which operates at lower temperatures and enables better renewable integration. This article investigates this challenge by examining the district heating potential within three scenarios: The first is a reference scenario with current heat demand and temperatures, the second includes heat demand...... costs. The models are applied using an example case of The Northern Region of Denmark. The article concludes that the district heating potential is highest in the reference scenario. When heat savings are introduced, district heating expansions, in most cases, will not be feasible. Introducing low...

  5. District heating and combined heat and power generation from biomass

    International Nuclear Information System (INIS)

    Veski, Rein

    1999-01-01

    An Altener programme seminar District Heating and Combined Heat and Power Generation from Biomass. Minitraining seminar and study tours and also Business forum, Exhibition and Short company presentations were held in Tallinn on March 21-23, 1999. The Seminar was organised by the VTT Energy, the Estonian Bioenergy Association and the Estonian Heat and Power Association in co-operation with the AFB-net. The Agricultural and Forestry Biomass Network (AFB-net) is part of the ALTENER programme. The Network aims at promoting and stimulating the implementation and commercial utilisation of energy from biomass and waste, through the initiation of business opportunities. This includes national and international co-operation and the exchange of the personnel. The Seminar was attended by consulting companies, scientists, municipal authorities and representatives of co-ordinating bodies engaged in renewable energy management as well as DH and CHP plant managers, equipment manufacturers and local energy planners from Finland, Estonia, Latvia, Lithuania, Sweden, Denmark, Belgium, Slovenia and Slovak Republic. At the Seminar minitraining issues were dealt with: the current situation and future trends in biomass DH in the Baltic Sea countries, and biomass DH and CHP in Eastern and Central Europe, planning and construction of biomass-based DH plants, biomass fuel procurement and handling technology, combustion technology, DH networks, financing of biomass projects and evaluating of projects, and case projects in Eastern and Central European countries. The following were presented: boilers with a capacity of 100 kW or more, stoker burners, wood and straw handling equipment, wood fuel harvesters, choppers, pelletisers, district heating pipelines and networks. (author)

  6. Performance Analysis of a Hybrid District Heating System

    DEFF Research Database (Denmark)

    Mikulandric, Robert; Krajačić, Goran; Duic, Neven

    2015-01-01

    Hybridisation of district heating systems can contribute to more efficient heat generation through cogeneration power plants or through the share increase of renewable energy sources in total energy consumption while reducing negative aspects of particular energy source utilisation. In this work......, the performance of a hybrid district energy system for a small town in Croatia has been analysed. Mathematical model for process analysis and optimisation algorithm for optimal system configuration has been developed and described. The main goal of the system optimisation is to reduce heat production costs....... Several energy sources for heat production have been considered in 8 different simulation cases. Simulation results show that the heat production costs could be reduced with introduction of different energy systems into an existing district heating system. Renewable energy based district heating systems...

  7. Environmental issues and competitiveness of district heating systems

    International Nuclear Information System (INIS)

    Kypreos, S.

    1991-01-01

    The advantages of district heating systems are evaluated in competition to individual heating for the Swiss markets. The preservation of the environmental quality on the national (clean air concept) and global scale (Toronto recommendation) is formulated as constraint of the energy system. The implications of these constraints for the economic competition of district heating is evaluated. The study estimates the evolution of energy demand in the heating markets and shortly describes the technical possibilities in satisfying demand by a set of conventional heating systems, systems using renewable energy sources, energy conservation measures and district heating systems based on conventional or nuclear energy sources. The main conclusion is that small capacity nuclear district heating systems, if acceptable, could enhance the flexibility of the Swiss energy system in respect to CO 2 control. (author) 3 figs., 4 tabs., 9 refs

  8. Improved district heating substation efficiency with a new control strategy

    International Nuclear Information System (INIS)

    Gustafsson, Jonas; Delsing, Jerker; Deventer, Jan van

    2010-01-01

    In this paper, we describe a new alternative control approach for indirectly connected district heating substations. Simulations results showed that the new approach results in an increased ΔT across the substation. Results were obtained for both ideal and non-ideal operation of the system, meaning that less water must be pumped through the district heating network, and a higher overall fuel efficiency can be obtained in the district heating power plants. When a higher fuel efficiency is achieved, the usage of primary fuel sources can be reduced. Improved efficiency also increases the effective heat transfer capacity of a district heating network, allowing more customers to be connected to an existing network without increasing the heating plant or network capacity. Also, if combined heat and power plants are used to produce the heat, the increased ΔT will result in a further improved overall fuel efficiency, as more electricity can be produced with colder cooling water. The idea behind the new control method is to consider the temperature of the water supplying the district heating substation with heat, often referred to as the primary supply temperature. This represents a logical next step, as currently, the only parameter generally taken into account or measured when controlling the temperature level of the radiator circuit is the local outdoor temperature. In this paper we show how the primary supply temperature together with thermodynamic knowledge of the building can be used to maximize the ΔT across the district heating substation.

  9. Condensation heat transfer of steam on a single horizontal tube

    Science.gov (United States)

    Graber, K. A.

    1983-06-01

    An experimental apparatus was designed, constructed and instrumented in an effort to systematically and carefully study the condensation heat-transfer coefficient on a single, horizontal tube. A smooth, thick-walled copper tube of length 133.5 mm, with an outside diameter of 15.9 mm and an inside diameter of 12.7 mm was instrumented with six wall thermocouples. The temperature rise across the test section was measured accurately using quartz crystal thermometers. The inside heat-transfer coefficient was determined using the Sieder-Tate correlation with leading coefficient of 0.029. Initial steam side data were taken at atmospheric pressure to test the data acquisition/reduction computer programs.

  10. Optimal usage of low temperature heat sources to supply district heating by heat pumps

    DEFF Research Database (Denmark)

    Pieper, Henrik; Ommen, Torben Schmidt; Markussen, Wiebke Brix

    2017-01-01

    This paper presents a theoretical study on the optimal usage of different low temperature heat sources to supply district heating by heat pumps. The study is based on data for the Copenhagen region. The heat sources were prioritized based on the coefficient of performance calculated for each hour...... and the covered demand of each heat source as well as required peak unit capacity. The results showed that heat pumps using different heat sources yield better performance than a heat pump based on a single one. The performance was influenced by the composition of the different heat sources. It was found that 78......% groundwater, 22% seawater and 0% air resulted in highest COP of 3.33 for the given heat demand. Furthermore, the implementation of rule based short term storage made peak units redundant. The variation in base load capacity showed that heat pumps utilizing the analyzed heat sources could perform very...

  11. Upscaling a district heating system based on biogas cogeneration and heat pumps

    NARCIS (Netherlands)

    van Leeuwen, Richard Pieter; Fink, J.; Smit, Gerardus Johannes Maria; de Wit, Jan B.

    2015-01-01

    The energy supply of the Meppel district Nieuwveense landen is based on biogas cogeneration, district heating, and ground source heat pumps. A centrally located combined heat and power engine (CHP) converts biogas from the municipal wastewater treatment facility into electricity for heat pumps and

  12. Economic and environmental efficiency of district heating plants

    DEFF Research Database (Denmark)

    Agrell, Per J.; Bogetoft, Peter

    2005-01-01

    heat, have arbitrary valuation.This study concerns the most developed European district heating and cogeneration system, the Danish.By assessing environmental and economic ef¿ciency, the impact of governmental, market and managerial imperfections are estimated.The principal methodological base......District heating, the conversion of primary energy into distributed thermal energy and possible electric energy, is a challenge to regulate.In addition to the ever present asymmetric information in any suf¿ciently complex activity, some of the inputs for district heating, such as excess process...

  13. Casing free district heating pipes; Mantelfria fjaerrvaermeroer

    Energy Technology Data Exchange (ETDEWEB)

    Saellberg, Sven-Erik; Nilsson, Stefan [Swedish National Testing and Research Inst., Goeteborg (Sweden)

    2005-07-01

    Previous studies have shown that polyurethane insulation (PUR foam) on district heating pipes acts as protection against water if it is of good quality, i.e. free from cracks, cavities and other defects. On the other hand water vapour easily diffuses through PUR foam. However this is not a problem as long as the steel pipe is warmer than the surface layer, since the high temperature will prevent the vapour from condensating. What will happen with the insulation of a casing free district heating pipe where the ground water level occasionally reaches above the pipe has not been studied in detail. The current project has studied to what extent moisture enters the PUR foam insulation of two approximately one meter long district heating pipes without casing which have been in the ground for four years. Occasionally, the ground-water has entirely covered the pipes. In addition, the foam has been studied with respect to damage from the surrounding backfill material. Test specimens were taken out of the casing free pipes and were analysed with respect to moisture content. Additional measurements were done with a moisture indicator, and the electric resistance between the steel pipes and the four surveillance wires in each pipe was measured. The results from the various measurement techniques were the compared. The results show that the PUR foam remains dry as long as the service pipe is hot if no defects, such as crack and cavities, are present. Close to the service pipe, the foam actually dries out over time. The moisture content of the middle layer remains more or less constant. Only the colder parts on the outside exhibit an increase in moisture content. It was also seen that defects may lead to water ingress with subsequent humidification of the foam. However, the damaged foam area is limited. This is not the case for a regular pipe with a vapour tight casing, where experience show that moisture tend to spread along the pipe. The pipes were buried in sand and no

  14. Market opening and third party access in district heating networks

    International Nuclear Information System (INIS)

    Soederholm, Patrik; Warell, Linda

    2011-01-01

    The purpose of this paper is to analyse the possible effects of introducing TPA in district heating networks by identifying and scrutinizing a number of possible scenarios for increased competition. The analysis builds on a theoretical discussion of economic efficiency in district heating operations, and the possible impacts on consumer prices of a market opening. An important conclusion is that regulated TPA may have small positive effects on competition, and at the same time it can have a negative impact on the possibility to run the integrated district heating operations in a cost-effective manner. This conclusion stems in part from the observation that most district heating networks are local in scope. Moreover, district heating operations are highly interdependent in, for instance, that the level of the return temperature of the water will affect the efficiency of combined heat and power plants. For these reasons, the introduction of the so-called single-buyer model or, perhaps even more preferable, an extended and more transparent producer market could represent more efficient market designs. Moreover, in networks with clear natural monopoly characteristics an ex ante price regulation must be considered. - Research Highlights: →The paper analyses the possible effects of TPA in district heating networks. → Four possible scenarios for increased competition are identified and scrutinized. → A conclusion is that regulated TPA have only small positive effects on competition. → District heating operations are highly interdependent and separation can be costly.

  15. Exergy and Energy Analysis of Low Temperature District Heating Network

    DEFF Research Database (Denmark)

    Li, Hongwei; Svendsen, Svend

    is in line with a pilot project that is carrying out in Denmark with network supply/return temperature at 55oC/25 oC. The consumer domestic hot water (DHW) demand is supplied with a special designed district heating (DH) storage tank. The space heating (SH) demand is supplied with a low temperature radiator......Low temperature district heating (LTDH) with reduced network supply and return temperature provides better match of the low quality building thermal demand and the low quality waste heat supply. In this paper, an exemplary LTDH network was designed for 30 low energy demand residential houses, which....... The network thermal and hydraulic conditions were simulated under steady state with an in-house district heating network design and simulation code. Through simulation, the overall system energetic and exergetic efficiencies were calculated and the exergy losses for the major district heating system...

  16. Energy and exergy analysis of low temperature district heating network

    DEFF Research Database (Denmark)

    Li, Hongwei; Svendsen, Svend

    2012-01-01

    is designed to supply heating for 30 low energy detached residential houses. The network operational supply/return temperature is set as 55 °C/25 °C, which is in line with a pilot project carried out in Denmark. Two types of in-house substations are analyzed to supply the consumer domestic hot water demand...... energy/exergy losses and increase the quality match between the consumer heating demand and the district heating supply.......Low temperature district heating with reduced network supply and return temperature provides better match of the low quality building heating demand and the low quality heating supply from waste heat or renewable energy. In this paper, a hypothetical low temperature district heating network...

  17. Integration of Space Heating and Hot Water Supply in Low Temperature District Heating

    DEFF Research Database (Denmark)

    Elmegaard, Brian; Ommen, Torben Schmidt; Markussen, Michael

    2014-01-01

    pipes, where the water is at the highest temperature. The heat loss may be lowered by decreasing the temperatures in the network for which reason low temperature networks are proposed as a low loss solution for future district heating. However, the heating demand of the consumers involve both domestic......District heating makes it possible to provide heat for many consumers in an efficient manner. In particular, district heating based on combined heat and power production is highly efficient. One disadvantage of district heating is that there is a significant heat loss from the pipes...... to the surrounding ground. In larger networks involving both transmission and distribution systems, the heat loss is most significant from the distribution network. An estimate is that about 80-90 % of the heat loss occurs in the distribution system. In addition, the heat loss is naturally highest from the forward...

  18. Integration of space heating and hot water supply in low temperature district heating

    DEFF Research Database (Denmark)

    Elmegaard, Brian; Ommen, Torben Schmidt; Markussen, Michael

    2016-01-01

    District heating may supply many consumers efficiently, but the heat loss from the pipes to the ground is a challenge. The heat loss may be lowered by decreasing the network temperatures for which reason low temperature networks are proposed for future district heating. The heating demand...... of the consumers involves both domestic hot water and space heating. Space heating may be provided at low temperature in low energy buildings. Domestic hot water, however, needs sufficient temperatures to avoid growth of legionella. If the network temperature is below the demand temperature, supplementary heating...... is required by the consumer. We study conventional district heating at different temperatures and compare the energy and exergetic efficiency and annual heating cost to solutions that utilize electricity for supplementary heating of domestic hot water in low temperature district heating. This includes direct...

  19. Evaluation of Excess Heat Utilization in District Heating Systems by Implementing Levelized Cost of Excess Heat

    Directory of Open Access Journals (Sweden)

    Borna Doračić

    2018-03-01

    Full Text Available District heating plays a key role in achieving high primary energy savings and the reduction of the overall environmental impact of the energy sector. This was recently recognized by the European Commission, which emphasizes the importance of these systems, especially when integrated with renewable energy sources, like solar, biomass, geothermal, etc. On the other hand, high amounts of heat are currently being wasted in the industry sector, which causes low energy efficiency of these processes. This excess heat can be utilized and transported to the final customer by a distribution network. The main goal of this research was to calculate the potential for excess heat utilization in district heating systems by implementing the levelized cost of excess heat method. Additionally, this paper proves the economic and environmental benefits of switching from individual heating solutions to a district heating system. This was done by using the QGIS software. The variation of different relevant parameters was taken into account in the sensitivity analysis. Therefore, the final result was the determination of the maximum potential distance of the excess heat source from the demand, for different available heat supplies, costs of pipes, and excess heat prices.

  20. Glas generator for the steam gasification of coal with nuclear generated heat

    International Nuclear Information System (INIS)

    Buchner, G.

    1980-01-01

    The use of heat from a High Temperature Reactor (HTR) for the steam gasification of coal saves coal, which otherwise is burnt to generate the necessary reaction heat. The gas generator for this process, a horizontal pressure vessel, contains a fluidized bed of coal and steam. An ''immersion-heater'' type of heat exchanger introduces the nuclear generated heat to the process. Some special design problems of this gasifier are presented. Reference is made to the present state of development of the steam gasification process with heat from high temperature reactors. (author)

  1. Heat transfer in the over-crisis region in a steam-generating channel with steam-droplet flow

    International Nuclear Information System (INIS)

    Nigmatulin, B.I.; Kukharenko, V.N.

    1991-01-01

    Statement and results of numerical solution of the problem on heat transfer in the over-crisis region under stationary and nonstationary conditions are studied. Two-temperature model, accounting for influence of phase slipping on heat exchange between steam and droplets and direct heat interaction with heated surface is used for describing steam-droplet flow. Comparison is made of calculational results and experimental data published in the literature on heated surface temperature within broad range of parameters: pressure - p=0.3-18.5 MPa; specific mass flow rate of the mixture - G=30-5000 kg/m 2 xs; specific heat flows - q=0.02-3 MW/m 2 and tube diameter - D=4-20 mm

  2. Calculating the marginal costs of a district-heating utility

    International Nuclear Information System (INIS)

    Sjoedin, Joergen; Henning, Dag

    2004-01-01

    District heating plays an important role in the Swedish heat-market. At the same time, the price of district heating varies considerably among different district-heating utilities. A case study is performed here in which a Swedish utility is analysed using three different methods for calculating the marginal costs of heat supply: a manual spreadsheet method, an optimising linear-programming model, and a least-cost dispatch simulation model. Calculated marginal-costs, obtained with the three methods, turn out to be similar. The calculated marginal-costs are also compared to the actual heat tariff in use by the utility. Using prices based on marginal costs should be able to bring about an efficient resource-allocation. It is found that the fixed rate the utility uses today should be replaced by a time-of-use rate, which would give a more accurate signal for customers to change their heat consumptions. (Author)

  3. Innovative system for delivery of low temperature district heating

    Directory of Open Access Journals (Sweden)

    Anton Ivanov Ianakiev

    2017-01-01

    Full Text Available An innovative Low Temperature District Heating (LTDH local network is developed in Nottingham, supported by REMOURBAN project, part of the H2020 Smart City and Community Lighthouse scheme. It was proposed that a branch emanating from the return pipe of the of the existing district heating system in Nottingham would be created to use low temperature heating for the first time in UK. The development is aimed to extract wasted (unused heat from existing district heating system and make it more efficient and profitable. Four maisonette blocks of 94 low-raised flats, at Nottingham demo site of the REMOURBAN project will be connected to this new LTDH system. The scheme will provide a primary supply of heat and hot water at approximately 50oC to 60oC. Innovated solutions have been put forward to overcome certain barriers, such as legionella related risks and peak loads during extreme heating seasons and occasional maintenance.

  4. Low Temperature District Heating for Future Energy Systems

    DEFF Research Database (Denmark)

    Ford, Rufus; Pietruschka, Dirk; Sipilä, Kari

    participants being VTT Technical Research Centre of Finland (VTT), Technical University of Denmark (DTU), Norwegian University of Science and Technology (NTNU), Stuttgart Technology University of Applied Sciences (HFT) and SSE Enterprise in United Kingdom. The demonstration cases described in the report......This report titled “Case studies and demonstrations” is the subtask D report of the IEA DHC|CHP Annex TS1 project “Low Temperature District Heating for Future Energy Systems” carried out between 2013 and 2016. The project was led by Fraunhofer Institute for Building Physics (IBP) with the other...... include examples on low temperature district heating systems, solar heating in a district heating system, heat pump based heat supply and energy storages for both peak load management and for seasonal heat storage. Some demonstrations have been implemented while others are at planning phase...

  5. Simulation Models to Size and Retrofit District Heating Systems

    Directory of Open Access Journals (Sweden)

    Kevin Sartor

    2017-12-01

    Full Text Available District heating networks are considered as convenient systems to supply heat to consumers while reducing CO 2 emissions and increasing renewable energies use. However, to make them as profitable as possible, they have to be developed, operated and sized carefully. In order to cope with these objectives, simulation tools are required to analyze several configuration schemes and control methods. Indeed, the most common problems are heat losses, the electric pump consumption and the peak heat demand while ensuring the comfort of the users. In this contribution, a dynamic simulation model of all the components of the network is described. It is dedicated to assess some energetic, environmental and economic indicators. Finally, the methodology is used on an existing application test case namely the district heating network of the University of Liège to study the pump control and minimize the district heating network heat losses.

  6. Thermodynamic analysis of heat recovery steam generator in combined cycle power plant

    Directory of Open Access Journals (Sweden)

    Ravi Kumar Naradasu

    2007-01-01

    Full Text Available Combined cycle power plants play an important role in the present energy sector. The main challenge in designing a combined cycle power plant is proper utilization of gas turbine exhaust heat in the steam cycle in order to achieve optimum steam turbine output. Most of the combined cycle developers focused on the gas turbine output and neglected the role of the heat recovery steam generator which strongly affects the overall performance of the combined cycle power plant. The present paper is aimed at optimal utilization of the flue gas recovery heat with different heat recovery steam generator configurations of single pressure and dual pressure. The combined cycle efficiency with different heat recovery steam generator configurations have been analyzed parametrically by using first law and second law of thermodynamics. It is observed that in the dual cycle high pressure steam turbine pressure must be high and low pressure steam turbine pressure must be low for better heat recovery from heat recovery steam generator.

  7. Nuclear source of district heating in the north-east region of Russia

    International Nuclear Information System (INIS)

    Dolgov, V.V.

    1998-01-01

    The operation of the Bilibin Nuclear Co-generation Plant (BNCP) as a local district heating source is reviewed in this paper. Specific features of the BNCP power unit are given with special emphases on the components of the technological scheme, which are involved in the heat production and supply to the consumers. The scheme of steam extraction from the turbine, the flow diagram of steam in the turbine, as well as the three circuit heat removal system are described. The numerical characteristics of the nuclear heat supply system in various operating modes are presented. The real information characterizing current radiological conditions in the vicinity of the heat generation and distribution equipment is also presented in the paper. The BNCP technical and economical characteristics are compared with those of conventional energy sources. Both advantages and some problems revealed during the twenty-year experience of the BNCP nuclear heat utilization are generally assessed. Safety and reliability characteristics of the reactor and the heat supply system are also described. (author)

  8. Future aspects for liquid metal heated steam generators

    International Nuclear Information System (INIS)

    Jansing, W.; Ratzel, W.; Vinzens, K.

    1975-01-01

    The present status of steam generators is shown. The experience gained until now is expressed in form of basic points. The most important design criteria for steam generator systems are outlined. On the basis of these design criteria, two possible steam generator concepts are shown. Costs in relationship to the repair concepts of two modular steam generators (thermal output 156 and 625 MW) and a pool design of 625 MW are compared. (author)

  9. Future aspects for liquid metal heated steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Jansing, W; Ratzel, W; Vinzens, K

    1975-07-01

    The present status of steam generators is shown. The experience gained until now is expressed in form of basic points. The most important design criteria for steam generator systems are outlined. On the basis of these design criteria, two possible steam generator concepts are shown. Costs in relationship to the repair concepts of two modular steam generators (thermal output 156 and 625 MW) and a pool design of 625 MW are compared. (author)

  10. Energy Analysis of Cascade Heating with High Back-Pressure Large-Scale Steam Turbine

    Directory of Open Access Journals (Sweden)

    Zhihua Ge

    2018-01-01

    Full Text Available To reduce the exergy loss that is caused by the high-grade extraction steam of traditional heating mode of combined heat and power (CHP generating unit, a high back-pressure cascade heating technology for two jointly constructed large-scale steam turbine power generating units is proposed. The Unit 1 makes full use of the exhaust steam heat from high back-pressure turbine, and the Unit 2 uses the original heating mode of extracting steam condensation, which significantly reduces the flow rate of high-grade extraction steam. The typical 2 × 350 MW supercritical CHP units in northern China were selected as object. The boundary conditions for heating were determined based on the actual climatic conditions and heating demands. A model to analyze the performance of the high back-pressure cascade heating supply units for off-design operating conditions was developed. The load distributions between high back-pressure exhaust steam direct supply and extraction steam heating supply were described under various conditions, based on which, the heating efficiency of the CHP units with the high back-pressure cascade heating system was analyzed. The design heating load and maximum heating supply load were determined as well. The results indicate that the average coal consumption rate during the heating season is 205.46 g/kWh for the design heating load after the retrofit, which is about 51.99 g/kWh lower than that of the traditional heating mode. The coal consumption rate of 199.07 g/kWh can be achieved for the maximum heating load. Significant energy saving and CO2 emission reduction are obtained.

  11. Technical assessment of electric heat boosters in low-temperature district heating based on combined heat and power analysis

    DEFF Research Database (Denmark)

    Cai, Hanmin; You, Shi; Wang, Jiawei

    2018-01-01

    This paper provides a technical assessment of electric heat boosters (EHBs) in low-energy districts. The analysis is based on a hypothetical district with 23 terraced single-family houses supplied by both a lowtemperature district heating (LTDH) network and a low-voltage network (LVN). Two case...

  12. A cold end to the district heating year

    International Nuclear Information System (INIS)

    Talsi, M.

    2003-01-01

    According to preliminary data from the Finnish District Heating Association, a total of 29.5 TWh of district heat was sold in Finland in 2002. Low temperatures in October, November, and December boosted sales over the year as a whole to virtually normal levels, despite the exceptionally warm early part of the year. Sales were up some 4 % on 2001 and totalled EUR 1.09 billion

  13. The future of the low temperature district heating reactor

    International Nuclear Information System (INIS)

    Lu Yingzhong; Wang Dazhong; Ma Changwen; Dong Duo; Tian Jiafu.

    1984-01-01

    In this paper, the role, development and situation of the low temperature district heating reactor (LTDHR) are briefly summarized. There are four types of LTDHR. They are PWR, reactor with boiling in the chimney, organic reactor and swimming pool reactor. The features of these reactors are introduced. The situation and role of the LTDHR in the future of the energy system are also discussed. The experiment on nuclear district heating with the swimming pool reactor in Qinghua Univ. is described briefly. (Author)

  14. Design and safety aspects of nuclear district heating reactors

    International Nuclear Information System (INIS)

    Brogli, R.; Mathews, D.; Pelloni, S.

    1989-01-01

    Extensive studies on the rationale, the potential and the technology of nuclear district heating have been performed in Switzerland. Beside economics the safety aspects were of primary importance. Due to the high costs to transport heat the heating reactor tend to be small and therefore, minimally staffed and located close to population centers. Stringed safety rules are therefore applying. Gas cooled reactors are well suited as district heating reactors since they have due to their characteristics several inherent features, significant safety margins and a remarkable radioactivity retention potential. Some ways to mitigate the effects of water ingress and graphite corrosion are under investigation. (author). 5 refs, 3 figs

  15. Spatiotemporal and economic analysis of industrial excess heat as a resource for district heating

    DEFF Research Database (Denmark)

    Bühler, Fabian; Petrović, Stefan; Holm, Fridolin Müller

    2018-01-01

    detailed analysis of the most suitable types of industries and the costs is required, allowing a targeted exploitation of this resource. This work extends the spatial and thermodynamic analysis, to account for the temporal match between industrial excess heat and district heating demands, as well...... as the costs for implementation and operation of the systems. This allows the determination of cost-effective district heating potentials, as well as the analysis of different industries and technological requirements. The results show that the temporal mismatch between excess heat and district heating demand...... and lack of demand, reduces the theoretical substitution potential by almost 30%. If heat storages are introduced, the total potential is reduced by only 10%. A majority of the excess heat can be utilised at socio-economic heating costs lower than the average Danish district heating price and the cost...

  16. Analysis of Decay Heat Removal by Natural Convection in LMR with a Combined Steam Generator

    International Nuclear Information System (INIS)

    Kim, Eui Kwang; Eoh, Jae Hyuk; Han, Ji Woong; Lee, Tae Ho

    2011-01-01

    Liquid metal reactors (LMRs) conventionally employ an intermediate heat transport system (IHTS) to protect the nuclear core during a sodium-water reaction (SWR) event. However these SWR-related components increase plant construction costs. In order to eliminate the need for an IHTS, a combined steam generator, which is an integrated heat exchanger of a steam generator and intermediate heat exchanger (IHX), was proposed by the Korea Atomic Energy Research Institute (KAERI). The objective of this work is to analyze the natural circulation heat removal capability of the rector system using a combined steam generator. As a means of decay heat removal, a normal heat transport path is composed of a primary sodium system, intermediate lead-bismuth circuit combined with SG and steam/water system. This paper presents the results of the possible temperature and natural circulation flows in all circuits during a steady state for a given reactor power level varied as a function of time

  17. STYLE, Steam Cycle Heat Balance for Turbine Blade Design in Marine Operation

    International Nuclear Information System (INIS)

    Love, J.B.; Dines, W.R.

    1970-01-01

    1 - Nature of physical problem solved: The programme carries out iterative steam cycle heat balance calculations for a wide variety of steam cycles including single reheat, live steam reheat and multistage moisture separation. Facilities are also available for including the steam-consuming auxiliaries associated with a marine installation. Though no attempt is made to carry out a detailed turbine blading design the programme is capable of automatically varying the blading efficiency from stage to stage according to local steam volume flow rate, dryness fraction and shaft speed. 2 - Method of solution: 3 - Restrictions on the complexity of the problem: Steam pressures to lie within range 0.2 to 5,000 lb/square inch abs steam temperatures to lie within range 50 to 1600 degrees F. Not more than 40 points per turbine expansion line; Not more than 10 expansion lines; Not more than 15 feed heaters. UNIVAC 1108 version received from FIAT Energia Nucleare, Torino, Italy

  18. Design of A District Heating System Including The Upgrading of Residual Industrial Waste Heat

    NARCIS (Netherlands)

    Falcao, P.W.; Mesbah, A.; Suherman, M.V.; Wennekes, S.

    2005-01-01

    This study was aimed to evaluate the feasibility of using a waste heat stream from DSM for a District Heating System. A conceptual design was carried out with emphasis on the unit for upgrading the residual waste heat. Having reviewed heat pump technology, mechanical heat pump was found to be the

  19. District heating systems for small scale development areas

    Energy Technology Data Exchange (ETDEWEB)

    McDougall, Rory e-mail: rory.mcdougall@online.no; Jensen, Bjoernulf

    2008-09-15

    Building projects are normally developed without considering integrated heating systems, especially where properties are for further sale. Due to focus on energy efficiency and environmental impact it is worth considering district heating systems, which include several energy carriers. The choice of energy carrier is assessed to optimize energy costs, account for environmental impact and obtain reliable heating supply, thus giving an energy flexible system for several buildings as opposed to individual heating systems in each building

  20. Improvements of reforming performance of a nuclear heated steam reforming process

    International Nuclear Information System (INIS)

    Hada, Kazuhiko

    1996-10-01

    Performance of an energy production process by utilizing high temperature nuclear process heat was not competitive to that by utilizing non-nuclear process heat, especially fossil-fired process heat due to its less favorable chemical reaction conditions. Less favorable conditions are because a temperature of the nuclear generated heat is around 950degC and the heat transferring fluid is the helium gas pressurized at around 4 MPa. Improvements of reforming performance of nuclear heated steam reforming process were proposed in the present report. The steam reforming process, one of hydrogen production processes, has the possibility to be industrialized as a nuclear heated process as early as expected, and technical solutions to resolve issues for coupling an HTGR with the steam reforming system are applicable to other nuclear-heated hydrogen production systems. The improvements are as follows: As for the steam reformer, (1) increase in heat input to process gas by applying a bayonet type of reformer tubes and so on, (2) increase in reforming temperature by enhancing heat transfer rate by the use of combined promoters of orifice baffles, cylindrical thermal radiation pipes and other proposal, and (3) increase in conversion rate of methane to hydrogen by optimizing chemical compositions of feed process gas. Regarding system arrangement, a steam generator and superheater are set in the helium loop as downstream coolers of the steam reformer, so as to effectively utilize the residual nuclear heat for generating feed steam. The improvements are estimated to achieve the hydrogen production rate of approximately 3800 STP-m 3 /h for the heat source of 10 MW and therefore will provide the potential competitiveness to a fossil-fired steam reforming process. Those improvements also provide the compactness of reformer tubes, giving the applicability of seamless tubes. (J.P.N.)

  1. Steam condensation process in a power production cycle and heat exchanger for it

    International Nuclear Information System (INIS)

    Tondeur, Gerard; Andro, Jean; Marjollet, Jacques; Pouderoux, Pierre.

    1982-01-01

    Steam condensation process in a power production cycle by expansion in turbines, characterized by the fact that this condensation is performed by the vaporization of a coolant with a vaporization temperature at atmospheric pressure lower than that of water, and that the vaporized coolant fluid is expanded in a turbine and then condensed by heat exchange with cold water being heated, while the liquefied coolant is recompressed and used for heat exchange with the steam to be condensed [fr

  2. Main results of assessing integrity of RNPP-3 steam generator heat exchange tubes in accident management

    International Nuclear Information System (INIS)

    Shugajlo, Al-j P.; Mustafin, M.A.; Shugajlo, Al-r P.; Ryzhov, D.I.; Zhabin, O.I.

    2017-01-01

    Tubes integrity evaluation under accident conditions considering drain of SG and current technical state of steam exchange tubes is an important question regarding SG long-term operation and improvement of accident management strategy.The main investigation results prepared for heat exchange surface of RNPP-3 steam generator are presented in this research aimed at assessing integrity of heat exchange tubes under accident conditions, which lead to full or partial drain of heat exchange surface, in particular during station blackout.

  3. Potentialities and type of integrating nuclear heating stations into district heating systems

    International Nuclear Information System (INIS)

    Munser, H.; Reetz, B.; Schmidt, G.

    1978-01-01

    Technical and economical potentialities of applying nuclear heating stations in district heating systems are discussed considering the conditions of the GDR. Special attention is paid to an optimum combination of nuclear heating stations with heat sources based on organic fuels. Optimum values of the contribution of nuclear heating stations to such combined systems and the economic power range of nuclear heating stations are estimated. Final considerations are concerned with the effect of siting and safety concepts of nuclear heating stations on the structure of the district heating system. (author)

  4. Device for district heating with utilization of waste heat from power plants

    International Nuclear Information System (INIS)

    Korek, J.

    1976-01-01

    In order to utilize the waste heat developing in power plants - especially in nuclear power plants - the author suggests to lead the waste heat of the coolers for oil (which the bearings are lubricated with), hydrogen (which serves for the stator rotor-cooling), and the stator cooling water to the circulating district heating water and to arrange these heat exchangers one behind another or parallel to each other in the water circuit of the district heating system. The oil cooler of the engine transformer is also connected with the circulation of the district heating water. The runback water of the district heating network could thus be heated from approx. 40 0 C up to 65 0 C. (UA) [de

  5. A heat transfer study for vertical straight-tube steam generators heated by liquid metal

    International Nuclear Information System (INIS)

    Valette, M.

    1984-04-01

    A single-tube mockup of a vertical straight-tube steam generator heated by sodium-potassium alloy NaK was submitted to thermal and hydraulic testing in conditions representative of fast breeder reactor operation. The mockup consisted of a 10mm I.D. ferritic steel heat exchange tube centered inside a cylindrical stainless steel shell. The complete assembly was 20.9 meters long. Water flowed upward inside the exchange tube, and NaK flowed downward in the annular gap between the tube and the shell. The steam outlet pressure ranged from 90 to 195 bars, while the liquid metal temperature at the mockup inlet was between 480 and 580 0 C. The water flowrate in the tube ranged from 153 to 2460 kg.m -2 .s -1 . During the tests the fluid inlet and outlet temperatures, flowrate and pressures were measured, as was the NaK temperature profile over the full length of the device. The test results were subsequently compared with heat exchange and pressure drop values calculated using the standard formulas for straight-tube heat exchangers. The heat exchange coefficients predicted by these correlations in the boiling zone were found to be largely overestimated, while the calculated pressure drop values proved satisfactory. A set of modified correlations is proposed to account for the observed phenomena, and for use in designing commercial units, provided the sodium flow in the tube bundle is adequately distributed

  6. District Heating Network Design and Configuration Optimization with Genetic Algorithm

    DEFF Research Database (Denmark)

    Li, Hongwei; Svendsen, Svend

    2013-01-01

    In this paper, the configuration of a district heating network which connects from the heating plant to the end users is optimized. Each end user in the network represents a building block. The connections between the heat generation plant and the end users are represented with mixed integer...... and the pipe friction and heat loss formulations are non-linear. In order to find the optimal district heating network configuration, genetic algorithm which handles the mixed integer nonlinear programming problem is chosen. The network configuration is represented with binary and integer encoding...... and it is optimized in terms of the net present cost. The optimization results indicates that the optimal DH network configuration is determined by multiple factors such as the consumer heating load, the distance between the heating plant to the consumer, the design criteria regarding the pressure and temperature...

  7. CMHC's district heating work may lead to solar power-towers

    Energy Technology Data Exchange (ETDEWEB)

    Peters, W

    1979-11-01

    A four-year study of district heating systems by the Canada Mortgage and Housing Corporation (CMHC) may combine with leadership recognition by the International Energy Agency to allow Canada to join the U.S. as the center for power-tower technology. The application of central receivers to district heating evolved from the district heating study as heliostat technology developed and the economics improved with scale. Based on the Barstow, Calif. prototype, a commercial version is envisioned for the mid-1980s to generate steam for power generation, heating, and cooling. A proponent suggests applying it to a multi-fuel system as a retrofit after the technology is perfected. Land availability and the need for direct sunlight present problems for this type of application in Canada, where much of the light is diffuse. A cautious view is taken by those who feel that cost will be prohibitive and who point out that the U.S. tests have yet to prove viability. (DCK)

  8. Feasibility Study on Solar District Heating in China

    DEFF Research Database (Denmark)

    Huang, Junpeng; Fan, Jianhua; Furbo, Simon

    This paper analyzes the feasibility of developing solar district heating (SDH) in China from the perspective of incentive policy, selections of technical route, regional adaptability and economic feasibility for clean heating. Based on the analyzation, this proposes a road map for the development...

  9. Policy incentives for flexible district heating in the Baltic countries

    DEFF Research Database (Denmark)

    Sneum, Daniel Møller; Sandberg, Eli; Koduvere, Hardi

    2018-01-01

    This study analyzes the impacts of taxes, subsidies, and electricity transmission and distribution tariffs and heat storage on the operation and economic feasibility of district heating plants with different flexibility potentials in the Baltic countries. Under 2016 conditions, the lowest levelized...

  10. On-line corrosion monitoring in geothermal district heating systems

    DEFF Research Database (Denmark)

    Richter, S.; Hilbert, Lisbeth Rischel; Thorarinsdottir, R.I.

    2006-01-01

    General corrosion rates in the geothermal district heating systems in Iceland are generally low, of the magnitude 1 lm/y. The reason is high pH (9.5), low-conductivity (200 lm/y) and negligible dissolved oxygen. The geothermal hot water is either used directly from source or to heat up cold ground...

  11. Analysis of Steam Heating of a Two-Layer TBP/N-Paraffin/Nitric Acid Mixtures

    International Nuclear Information System (INIS)

    Laurinat, J.E.; Hassan, N.M.; Rudisill, T.S.; Askew, N.M.

    1998-01-01

    This report presents an analysis of steam heating of a two-layer tri-n-butyl phosphate (TBP)/n-paraffin-nitric acid mixture.The purpose of this study is to determine if the degree of mixing provided by the steam jet or by bubbles generated by the TBP/nitric acid reaction is sufficient to prevent a runaway reaction

  12. Dedicated low temperature nuclear district heating plants: Rationale and prospects

    International Nuclear Information System (INIS)

    Goetzmann, C.A.

    1997-01-01

    Space heating accounts for a substantial fraction of the end-energy consumption in a large number of industrialized countries. Accordingly, efforts have been under way since many years to utilize nuclear energy as a source for district heating. The paper describes the key technical and institutional issues affecting the implementation of such technology. It is argued that the basic case for nuclear district heating is sound but that its introduction merits and drawbacks strongly depend on local circumstances. (author). 4 figs, 1 tab

  13. Dream aim reached: 1300 operational district heating supply connections

    Energy Technology Data Exchange (ETDEWEB)

    Handl, K H

    1988-11-01

    Only four years after the beginning of operation of the first consumer station at Klingnau on October 19, 1984, the Regional District Heating Supply in the Lower Aare Valley (Refuna) can already show 1295 operational district heating connections. There are almost 300 more than one year ago and about 20% more than originally foreseen during this short construction time. As in recent years, the number of consumers has significantly increased during a 'connection boom' in the first autumn weeks. The total heat supply power amounts to 51500 kilowatts. This is 70% of the power foreseen in the final stage. 3 figs., 1 tab.

  14. Conversion of individual natural gas to district heating

    DEFF Research Database (Denmark)

    Möller, Bernd; Lund, Henrik

    2010-01-01

    Replacing individual natural gas heating with district heating based to increasing shares of renewable energy sources may further reduce CO2-emissions in the Danish Building mass, while increasing flexibility of the energy system to accommodate significantly larger amounts of variable renewable...... energy production. The present paper describes a geographical study of the potential to expand district heating into areas supplied with natural gas. The study uses a highly detailed spatial database of the built environment, its current and potential future energy demand, its supply technologies and its...

  15. A new district heating system in the city of Bolanzo

    DEFF Research Database (Denmark)

    Mazzocato, Alessandro; Li, Hongwei; Marchiori, S.

    2014-01-01

    In the context of the EU project “Sinfonia”, that aims to reduce Bolzano’s primary energy consumption up to 40%, SEL AG, an Italian energy company is planning to extend the existing district heating and cooling (DHC) network and explore strategies to improve efficiency, environmental, and economic...... performance. This research aims to assess the potential energy saving of temperature and peak heating load reduction in the Bolzano’s DHC network. Historical performance data from district heating (DH) users were collected and residential building were classified based on construction year and energy...

  16. Energy source completion for geothermal district heating systems

    International Nuclear Information System (INIS)

    Popovski, Kiril

    2000-01-01

    Geothermal district heating systems differs from the others mainly in the part of energy source completion and its connection to the heat distribution systems rather known problem. Even rather known problematic in the countries where geothermal energy is in wide application, new appearances of mistakes are always present due to the fact that necessary literature is difficult to be found. Essentials of the geothermal well completion and connection of geothermal source to the district heating distribution system are summarized in the paper and several examples of geothermal projects in flow are presented. (Author)

  17. Dedicated low temperature nuclear district heating plants: Rationale and prospects

    Energy Technology Data Exchange (ETDEWEB)

    Goetzmann, C A [Division of Nuclear Power, International Atomic Energy Agency, Vienna (Austria)

    1997-09-01

    Space heating accounts for a substantial fraction of the end-energy consumption in a large number of industrialized countries. Accordingly, efforts have been under way since many years to utilize nuclear energy as a source for district heating. The paper describes the key technical and institutional issues affecting the implementation of such technology. It is argued that the basic case for nuclear district heating is sound but that its introduction merits and drawbacks strongly depend on local circumstances. (author). 4 figs, 1 tab.

  18. Efficiency potential in the district heating sector. Final report

    International Nuclear Information System (INIS)

    Agrell, P.; Bogetoft, P.; Fristrup, P.; Munksgaard, J.; Pade, L.L.

    2003-10-01

    This report is the final documentation for the research project 'District heating prices in a liberalised energy market - benchmarking the production of combined heat and power'. The project compares activities for almost 300 companies, members of the Danish District Heating Society. The main aim of the analyses has been to uncover the saving potential by comparing each individual company to the most efficient companies in the sector. The variable costs have been studied, amounting to almost 7 billion Danish kroner a year, and the analyses found saving potential ranging from 5% to 60% dependent on the expectations to flexibility assigned to the individual companies. The data used are not available for the public as they exceed the Danish District Heating Society's annual statistics. (BA)

  19. Smart energy systems and 4th generation district heating

    DEFF Research Database (Denmark)

    Lund, Henrik; Duic, Neven; Østergaard, Poul Alberg

    2016-01-01

    scientific understanding on how we can design and implement a suitable and least-cost transformation into a sustainable energy future. The concept of Smart Energy Systems emphasizes the importance of being coherent and cross-sectoral when the best solutions are to be found and how this also calls......This editorial gives an introduction to the important relationship between Smart Energy Systems and 4th Generation District Heating and presents a number of selected papers from the 1st International Conference on the topic. All of the papers elaborate on or otherwise contribute to the theoretical...... for the active inclusion of the heating and cooling sectors. The concept of 4th Generation District Heating emphasizes that district heating and cooling are both important elements but also technologies that have to be developed further into a 4th generation version to be able to fulfil their roles in future...

  20. Utilization of straw in district heating and CHP plants

    International Nuclear Information System (INIS)

    Nikolaisen, L.

    1993-01-01

    In Denmark 64 straw-fired district heating plants and 6 decentral CHP plants have been built since 1980 which are completely or partly straw-fired. The annual straw consumption in the district heating plants is 275,000 tons and in the decentral plants about 200,000 tons. The size of the district heating plants amounts to 0.5 MW - 10 MW and that of the CHP plants to 7 MW - 67 MW heat flow rate. Either whole bales or cut/scarified straw is used for firing. Hesston bales of about 450 kg control the market. The Centre of Biomass Technology is an activity supported 100 % by the Danish Energy Agency with the purpose of increasing the use of straw and wood in the energy supply (orig.)

  1. Uncertainties in the daily operation of a district heating plant

    DEFF Research Database (Denmark)

    Sorknæs, Peter

    Studies have found that district heating (DH) systems should play an important role in future sustainable energy systems, but that DH has to adapt to lower heat demands. This means adapting to reduced operation hours for units essential for DHs integration in other parts of the energy system......, such as CHP. It will therefore likely be increasingly important to increase the value per operation hour. The value can be increased by offering balancing for the electricity system. This in turn increases the uncertainties in the daily operation planning of the DH system. In this paper the Danish DH plant...... Ringkøbing District Heating is used as a case to investigate what costs market uncertainties can incur on a DH plant. It is found that the market uncertainties in a 4 months simulated period increased Ringkøbing District Heatings costs by less than 1%. Several factors are however not included in this paper....

  2. District heating and co-generation in Slovenia

    International Nuclear Information System (INIS)

    Hrovatin, Franc; Pecaric, Marko; Perovic, Olgica

    2000-01-01

    Recent development of district heating systems, gasification and co-generation processes in local communities in Slovenia as well as current status, potentials, possibilities and plans for further development in this sphere are presented. The current status presents energy production, distribution and use in district heating systems and in local gas distribution networks. An analysis of the energy and power generated and distributed in district power systems, made with regard to the size of the system, fuel used, type of consumers and the way of production, is given. Growth in different areas of local power systems in the period of last years is included. Potentials in the sphere of electrical energy and heat co-generation were assessed. Some possibilities and experience in heat energy storage are given and trends and plans for further development are introduced. (Authors)

  3. Reactor waste heat utilization and district heating reactors. Nuclear district heating in Sweden - Regional reject heat utilization schemes and small heat-only reactors

    International Nuclear Information System (INIS)

    Hannerz, K.; Larsson, Y.; Margen, P.

    1977-01-01

    A brief review is given of the current status of district heating in Sweden. In future, district heating schemes will become increasingly interesting as a means of utilizing heat from nuclear reactors. Present recommendations in Sweden are that large reactors should not be located closer than about 20 km from large population centres. Reject heat from such reactors is cheap at source. To minimize the cost of long distance hot water transmission large heat rates must be transmitted. Only areas with large populations can meet this requirement. The three areas of main interest are Malmoe/Lund/Helsingborg housing close to 0.5 million; Greater Stockholm housing 1 to 1.5 million and Greater Gothenburg housing about 0.5 million people. There is an active proposal that the Malmoe/Lund/Helsingborg region would be served by a third nuclear unit at Barsebaeck, located about 20 km from Malmoe/Lund and supplying 950 MW of base load heat. Preliminary proposals for Stockholm involve a 2000 MW heat supply; proposals for Gothenburg are more tentative. The paper describes progress on these proposals and their technology. It also outlines technology under development to increase the economic range of large scale heat transport and to make distribution economic even for low heat-density family housing estates. Regions apart from the few major urban areas mentioned above require the adoption of a different approach. To this end the development of a small, simple low-temperature reactor for heat-only production suitable for urban location has been started in Sweden in close contact with Finland. Some results of the work in progress are presented, with emphasis on the safety requirements. An outline is given in the paper as to how problems of regional heat planning and institutional and legislative issues are being approached

  4. Integration of biomass fast pyrolysis and precedent feedstock steam drying with a municipal combined heat and power plant

    International Nuclear Information System (INIS)

    Kohl, Thomas; Laukkanen, Timo P.; Järvinen, Mika P.

    2014-01-01

    Biomass fast pyrolysis (BFP) is a promising pre-treatment technology for converting biomass to transport fuel and in the future also for high-grade chemicals. BFP can be integrated with a municipal combined heat and power (CHP) plant. This paper shows the influence of BFP integration on a CHP plant's main parameters and its effect on the energetic and environmental performance of the connected district heating network. The work comprises full- and part-load operation of a CHP plant integrated with BFP and steam drying. It also evaluates different usage alternatives for the BFP products (char and oil). The results show that the integration is possible and strongly beneficial regarding energetic and environmental performance. Offering the possibility to provide lower district heating loads, the operation hours of the plant can be increased by up to 57%. The BFP products should be sold rather than applied for internal use as this increases the district heating network's primary energy efficiency the most. With this integration strategy future CHP plants can provide valuable products at high efficiency and also can help to mitigate global CO 2 emissions. - Highlights: • Part load simulation of a cogeneration plant integrated with biomas fast pyrolysis. • Analysis of energetic and environmental performance. • Assessment of different uses of the pyrolysis products

  5. Study and optimization of operating regimes of NPP district heating system

    International Nuclear Information System (INIS)

    Bunin, V.S.; Vasil'ev, M.K.; Kudryavtsev, A.A.; Gorbashev, Yu.B.; Gadzhij, V.M.

    1980-01-01

    Thermal tests of the system with two reactors and four turbines have been carried out for the purpose of verification of operating regimes of the NPP district heating system with boiling single-curcuit RBMK-1000 reactors and K-500-65/3000 turbines. The system is designed for heat supply of habitable settlement and industrial site. The data processing have been carried out by the BESM-6 computer representing distributions of heat flow, steam, water and their parameters and determining the main energy indices of the system. Calculations of the system operating regime variables during the year have been carried out with the help of this program. It has been expected that the system provided heat consumption of 232 MW at calculated regime of thermal loading of the district, temperature regime of the system water of 130/170 deg C, relative load of hot water supply of 0.2 and duration of heating period of 4800 h. Calculations demonstrated that distric heat supply by NPP allowed one to supplant about 85 thous. of reference fuel/year of organic fuel. About 63 thous. of reference fuel/year are required for compensation of decrease of electric energy production in a condensation cycle. It has been also shown, that replacing the four-stroke system heaters by one-stroke heaters permits to drop system water underheating 1.5 times and, respectively, electric energy underproduction to 72 mln Mj (20 mln, kWxh). It produces additional economy of 6.6 thous. reference fuel/year. Calculations of its heat system have been conducted in order to determine the influence of water consumption in an intermediate circuit on the system efficiency. It has been shown that with the increase of water consumption energy power losses decrease. Thus, the above studied have demonstrated that the use of the single-circuit NPP district heating systems leads to considerable economy of fuel

  6. Dynamic study of steam generation from low-grade waste heat in a zeolite–water adsorption heat pump

    International Nuclear Information System (INIS)

    Xue, Bing; Meng, Xiangrui; Wei, Xinli; Nakaso, Koichi; Fukai, Jun

    2015-01-01

    A novel zeolite–water adsorption heat pump system based on a direct-contact heat exchange method to generate steam from low-grade waste gas and water has been proposed and examined experimentally. Superheated steam (200 °C, 0.1 MPa) is generated from hot water (70–80 °C) and dry air (100–130 °C). A dynamic model for steam generation process is developed to describe local mass and heat transfer. This model features a three-phase calculation and a moving water–gas interface. The calculations are carried out in the zeolite–water and zeolite–gas regions. Model outputs are compared with experimental results for validation. The thermal response inside the reactor and mass of steam generated is well predicted. Numerical results show that preheat process with low-temperature steam is an effective method to achieve local equilibrium quickly, thus generation process is enhanced by prolonging the time and increasing mass of the generated steam. Besides, high-pressure steam generation up to 0.5 MPa is possible from the validated dynamic model. Future work could be emphasized on enhancing high-pressure steam generation with preheat process or mass recovery operation

  7. Comparative Study of Convective Heat Transfer Performance of Steam and Air Flow in Rib Roughened Channels

    Science.gov (United States)

    Ma, Chao; Ji, Yongbin; Ge, Bing; Zang, Shusheng; Chen, Hua

    2018-04-01

    A comparative experimental study of heat transfer characteristics of steam and air flow in rectangular channels roughened with parallel ribs was conducted by using an infrared camera. Effects of Reynolds numbers and rib angles on the steam and air convective heat transfer have been obtained and compared with each other for the Reynolds number from about 4,000 to 15,000. For all the ribbed channels the rib pitch to height ratio (p/e) is 10, and the rib height to the channel hydraulic diameter ratio is 0.078, while the rib angles are varied from 90° to 45°. Based on experimental results, it can be found that, even though the heat transfer distributions of steam and air flow in the ribbed channels are similar to each other, the steam flow can obtain higher convective heat transfer enhancement capability, and the heat transfer enhancement of both the steam and air becomes greater with the rib angle deceasing from 90° to 45°. At Reynolds number of about 12,000, the area-averaged Nusselt numbers of the steam flow is about 13.9%, 14.2%, 19.9% and 23.9% higher than those of the air flow for the rib angles of 90°, 75°, 60° and 45° respectively. With the experimental results the correlations for Nusselt number in terms of Reynolds number and rib angle for the steam and air flow in the ribbed channels were developed respectively.

  8. Improving the performance of district heating systems by utilization of local heat boosters

    DEFF Research Database (Denmark)

    Falcone, A.; Dominkovic, D. F.; Pedersen, A. S.

    was to evaluate the possibilities to lower the forward temperature of the heat supply in order to reduce the heat losses of the system. Booster heat pumps are introduced to increase the water temperature close to the final users. A Matlab model was developed to simulate the state of the case study DH network...... was set to minimize the system heat losses. * Corresponding author 0303-1 1 This goal was achieved by lowering the forward temperature to 40°C and relying on the installed heat pumps to boost the water temperature to the admissible value needed for the domestic hot water preparation. Depending......District Heating (DH) plays an important role into the Danish energy green transition towards the future sustainable energy systems. The new, 4 th generation district heating network, the so called Low Temperature District Heating (LTDH), tends to lower the supply temperature of the heat down to 40...

  9. District heating rehabilitation project. Viljandi - Estonia. Final report

    International Nuclear Information System (INIS)

    1998-04-01

    The main objective of the project has been to assist Viljandi Municipality with the rehabilitation of their district heating system, and thereby to support the positive development of the district heating system in Viljandi to a more energy efficient and rational system and to achieve a significantly decrease in the pollution from the production of heat energy in Viljandi. The project has also included technical assistance to Viljandi DH company, in order to make them capable of operation and maintaining of the new substations, and also training of the local operational staff for operation of the complete district heating system. Viljandi is a county and is centrally located in Estonia, which makes Viljandi very suitable as recipient for a demonstration project. One important objective was the projects significantly positive environmental impact in reduction of the generated emissions of CO 2 , NO x and SO 2 , as the project includes installation of more efficient energy systems and supply of heat from the 2 existing district heating plants (both are partly fired with wood chips) instead of heating by very old and worn-out coal fired boilers and inexpedient designed substations with the present operational conditions. (EG)

  10. District heating rehabilitation project. Viljandi - Estonia. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-04-01

    The main objective of the project has been to assist Viljandi Municipality with the rehabilitation of their district heating system, and thereby to support the positive development of the district heating system in Viljandi to a more energy efficient and rational system and to achieve a significantly decrease in the pollution from the production of heat energy in Viljandi. The project has also included technical assistance to Viljandi DH company, in order to make them capable of operation and maintaining of the new substations, and also training of the local operational staff for operation of the complete district heating system. Viljandi is a county and is centrally located in Estonia, which makes Viljandi very suitable as recipient for a demonstration project. One important objective was the projects significantly positive environmental impact in reduction of the generated emissions of CO{sub 2}, NO{sub x} and SO{sub 2}, as the project includes installation of more efficient energy systems and supply of heat from the 2 existing district heating plants (both are partly fired with wood chips) instead of heating by very old and worn-out coal fired boilers and inexpedient designed substations with the present operational conditions. (EG)

  11. Steam generator concept of a small HTR for reheating and for removal of the residual heat

    Energy Technology Data Exchange (ETDEWEB)

    Singh, J; Barnert, H; Hohn, H; Mondry, M [Institut fuer Reaktorenentwicklung, Kernforschungsanlage Juelich GmbH, Juelich (Germany)

    1988-07-01

    The steam generator of a small HTR is arranged above the core in an in line design of the primary loop, thereby helium flows upwards. Water flows downwards in the steam generator to realize cross flow. To achieve stable evaporation conditions during part load operation it is desired to realize upward evaporation in the steam generator. Moreover if the steam generator is also used as a heat sink for removal of residual heat, this desire of upwards evaporation becomes more imperative. It is possible to realize the design of steam generator with upwards evaporation by arranging a hot gas duct in its central region, so that hot helium can flow upwards through it. Therefore helium enters the steam generator from the top and flows downwards and water upwards. In the presented design, a heat exchanger is arranged in the central region of the steam generator instead of a hot gas duct. Hot helium of 750 deg. C flows upwards in this heat exchanger and thereby cools down to the temperature of about 700 deg. C before it enters the bundle of the steam generator at the top. Through an intermediate loop this heat is transferred outside the primary loop, where in an extra heat exchanger live steam is reheated to improve the thermal efficiency of the plant. This intermediate loop works on the basis of forced convection and transfer about 25 MW for reheating. During the shutdown operation of the reactor, this heat exchanger in the central region of the steam generator serves as a heat sink for removal of the residual heat through natural convection in the primary loop. At the same time it is further possible, that intermediate loop also works on the basis of natural convection, because during shutdown operation only a very small amount of heat has to be removed and moreover the outside heat exchanger can be arranged much higher above the central heat exchanger to get favourable conditions for the natural convection. Some of the highlights of the central heat exchanger are: coaxial

  12. Nuclear district heating. 1. Process heat reactors and transmission and distribution networks

    International Nuclear Information System (INIS)

    Caizergues, R.

    1979-01-01

    Three kinds of production station are considered: joint electricity and heat-producing stations, heat-producing stations with CAS reactors and heat-producing stations with Thermos reactors. The thermal energy supply possibilities of these stations, the cost price of this energy and the cost price per therm produced by the district heating source and conveyed to the user are studied [fr

  13. Geothermal energy developments in the district heating of Szeged

    OpenAIRE

    Osvald, Máté; Szanyi, János; Medgyes, Tamás; Kóbor, Balázs; Csanádi, Attila

    2017-01-01

    The District Heating Company of Szeged supplies heat and domestic hot water to 27,000 households and 500 public buildings in Szeged. In 2015, the company decided to introduce geothermal sources into 4 of its 23 heating circuits and started the preparation activities of the development. Preliminary investigations revealed that injection into the sandstone reservoir and the hydraulic connection with already existing wells pose the greatest hydrogeological risks, while placement and operation of...

  14. Dynamic underground stripping: steam and electric heating for in situ decontamination of soils and groundwater

    Science.gov (United States)

    Daily, William D.; Ramirez, Abelardo L.; Newmark, Robin L.; Udell, Kent; Buetnner, Harley M.; Aines, Roger D.

    1995-01-01

    A dynamic underground stripping process removes localized underground volatile organic compounds from heterogeneous soils and rock in a relatively short time. This method uses steam injection and electrical resistance heating to heat the contaminated underground area to increase the vapor pressure of the contaminants, thus speeding the process of contaminant removal and making the removal more complete. The injected steam passes through the more permeable sediments, distilling the organic contaminants, which are pumped to the surface. Large electrical currents are also applied to the contaminated area, which heat the impermeable subsurface layers that the steam has not penetrated. The condensed and vaporized contaminants are withdrawn by liquid pumping and vacuum extraction. The steam injection and electrical heating steps are repeated as necessary. Geophysical imaging methods can be used to map the boundary between the hot, dry, contamination-free underground zone and the cool, damp surrounding areas to help monitor the dynamic stripping process.

  15. Heat planning for fossil-fuel-free district heating areas with extensive end-use heat savings: A case study of the Copenhagen district heating area in Denmark

    International Nuclear Information System (INIS)

    Harrestrup, M.; Svendsen, S.

    2014-01-01

    The Danish government plans to make the Danish energy system to be completely free of fossil fuels by 2050 and that by 2035 the energy supply for buildings and electricity should be entirely based on renewable energy sources. To become independent from fossil fuels, it is necessary to reduce the energy consumption of the existing building stock, increase energy efficiency, and convert the present heat supply from fossil fuels to renewable energy sources. District heating is a sustainable way of providing space heating and domestic hot water to buildings in densely populated areas. This paper is a theoretical investigation of the district heating system in the Copenhagen area, in which heat conservation is related to the heat supply in buildings from an economic perspective. Supplying the existing building stock from low-temperature energy resources, e.g. geothermal heat, might lead to oversized heating plants that are too expensive to build in comparison with the potential energy savings in buildings. Long-term strategies for the existing building stock must ensure that costs are minimized and that investments in energy savings and new heating capacity are optimized and carried out at the right time. - Highlights: • We investigate how much heating consumption needs to be reduced in a district heating area. • We examine fossil-fuel-free supply vs. energy conservations in the building stock. • It is slightly cost-beneficial to invest in energy renovation from today for a societal point of view. • It is economically beneficial for district heating companies to invest in energy renovations from today. • The cost per delivered heat unit is lower when energy renovations are carried out from today

  16. Study of an innovative ejector heat pump-boosted district heating system

    International Nuclear Information System (INIS)

    Zhang, Bo; Wang, Yuanchao; Kang, Lisha; Lv, Jinsheng

    2013-01-01

    An Ejector heat pump-boosted District Heating (EDH) system is proposed to improve the heating capacity of existing district heating systems with Combined Heat and Power (CHP). In the EDH, two ejector heat pumps are installed: a primary heat pump (HP 1 ) at the heating station and a secondary heat pump (HP 2 ) at the heating substation. With the EDH, the low-grade waste heat from circulating cooling water in the CHP is recycled and the temperature difference between the water supply and the return of the primary heating network is increased. A thermodynamic model was provided. An experimental study was carried out for both HP 1 and HP 2 to verify the predicting performance. The results show that the COP of HP 1 can reach 1.5–1.9, and the return water temperature of the primary heating network could be decreased to 35 °C with HP 2 . A typical case study for the EDH was analyzed. -- Highlights: • An ejector heat pump-boosted district heating (EDH) is proposed. • The 1st ejector heat pump in EDH recycles heat from cooling water of the CHP. • The 2nd ejector heat pump in EDH boosts the thermal energy utilization of the primary heating network. • Modeling and experimental studies are presented

  17. Dryout in sodium-heated helically-coiled steam generator tubes

    International Nuclear Information System (INIS)

    Tomita, Y.; Kosugi, T.; Kubota, J.; Nakajima, K.; Tsuchiya, T.

    1984-01-01

    Experimental research on the dryout phenomenon in sodium heated, helically coiled steam generator tubes was carried out. The fluctuation of the tube wall temperature caused by dryout was measured with thermocouples installed in the center of the tube wall. Empirical correlations of dryout quality were developed as functions of critical heat flux, water mass velocity and saturation pressure. These correlations confirmed that the design criterion of the MONJU steam generator was reasonable. (author)

  18. Thermodynamic performance analysis and algorithm model of multi-pressure heat recovery steam generators (HRSG) based on heat exchangers layout

    International Nuclear Information System (INIS)

    Feng, Hongcui; Zhong, Wei; Wu, Yanling; Tong, Shuiguang

    2014-01-01

    Highlights: • A general model of multi-pressure HRSG based on heat exchangers layout is built. • The minimum temperature difference is introduced to replace pinch point analysis. • Effects of layout on dual pressure HRSG thermodynamic performances are analyzed. - Abstract: Changes of heat exchangers layout in heat recovery steam generator (HRSG) will modify the amount of waste heat recovered from flue gas; this brings forward a desire for the optimization of the design of HRSG. In this paper the model of multi-pressure HRSG is built, and an instance of a dual pressure HRSG under three different layouts of Taihu Boiler Co., Ltd. is discussed, with specified values of inlet temperature, mass flow rate, composition of flue gas and water/steam parameters as temperature, pressure etc., steam mass flow rate and heat efficiency of different heat exchangers layout of HRSG are analyzed. This analysis is based on the laws of thermodynamics and incorporated into the energy balance equations for the heat exchangers. In the conclusion, the results of the steam mass flow rate, heat efficiency obtained for three heat exchangers layout of HRSGs are compared. The results show that the optimization of heat exchangers layout of HRSGs has a great significance for waste heat recovery and energy conservation

  19. IAEA Technical Meeting on Innovative Heat Exchanger and Steam Generator Designs for Fast Reactors. Working Material

    International Nuclear Information System (INIS)

    2011-01-01

    The IAEA, within the framework of its Nuclear Energy Department’s Technical Working Group on Fast Reactors (TWG-FR), assists Member States activities in fast reactors technology development areas by providing an umbrella for information exchange [topical Technical Meetings (TMs), Workshops and large Conferences] and collaborative R&D [Coordinated Research Projects (CRPs)]. The Technical meeting on “Innovative Heat Exchanger and Steam Generator Designs for Fast Reactors” was held from 21 – 22 December 2011 in Vienna, addressing Member States’ expressed needs of information exchange in the field of advanced fast reactor design features, with particular attention to innovative heat exchangers and steam generators. The Objective of the TM is to provide a global forum for in-depth information exchange and discussion on the most advanced concepts of heat exchangers and steam generators for fast reactors. More specifically, the objectives are: · Review of the status of advanced fast reactor development activities with special emphasis on design and performance of heat exchangers and steam generators; · Discuss requirements for innovative heat exchangers and steam generators; · Present results of studies and conceptual designs for innovative heat exchangers and steam generators; · Provide recommendations for international collaboration under the IAEA aegis. The meeting agenda of the meeting is in Annex I

  20. MHTGR steam generator on-line heat balance, instrumentation and function

    International Nuclear Information System (INIS)

    Klapka, R.E.; Howard, W.W.; Etzel, K.T.; Basol, M.; Karim, N.U.

    1991-09-01

    Instrumentation is used to measure the Modular High Temperature Gas-Cooled Reactor (MHTGR) steam generator dissimilar metal weld temperature during start-up testing. Additional instrumentation is used to determine an on-line heat balance which is maintained during the 40 year module life. In the process of calibrating the on-line heat balance, the helium flow is adjusted to yield the optimum boiling level in the steam generator relative to the dissimilar metal weld. After calibration is complete the weld temperature measurement is non longer required. The reduced boiling level range results in less restrictive steam generator design constraints

  1. Specification of steam generator, condenser and regenerative heat exchanger materials for nuclear applications

    International Nuclear Information System (INIS)

    Jovasevic, J.V.; Stefanovic, V.M.; Spasic, Z.LJ.

    1977-01-01

    The basic standards specifications of materials for nuclear applications are selected. Seamless Ni-Cr-Fe alloy Tubes (Inconel-600) for steam generators, condensers and other heat exchangers can be employed instead of austenitic stainless steal or copper alloys tubes; supplementary requirements for these materials are given. Specifications of Ni-Cr-Fe alloy plate, sheet and strip for steam generator lower sub-assembly, U-bend seamless copper-alloy tubes for heat exchanger and condensers are also presented. At the end, steam generator channel head material is proposed in the specification for carbon-steel castings suitable for welding

  2. Twin cities institutional issues study cogenerated hot water district heating

    Energy Technology Data Exchange (ETDEWEB)

    Sundberg, R. E.; Leas, R.; Kolb, J. O.

    1979-01-01

    Community district heating, utilizing hot water produced through electrical/thermal cogeneration, is seen as an integral part of Minnesota's Energy Policy and Conservation Plan. Several studies have been conducted which consider the technical and institutional issues affecting implementation of cogenerated district heating in the Minneapolis and St. Paul Metropolitan Area. The state of the technical art of cogenerated hot water district heating is assumed to be transferable from European experience. Institutional questions relating to such factors as the form of ownership, financing, operation, regulation, and product marketability cannot be transferred from the European experience, and have been the subject of an extensive investigation. The form and function of the Institutional Issues Study, and some of the preliminary conclusions and recommendations resulting from the study are discussed.

  3. The situation of district heating, district cooling and energy supply in Hungary

    International Nuclear Information System (INIS)

    Sigmond, Gy.

    2009-01-01

    District heating represents with 650.000 heated dwellings approximately 15% of the Hungarian residential heating market. Since 1990 there is stagnation at the number of connected dwellings because erection of large settlements with prefab buildings has been stopped, and latter ones represent more than 75% of the dwelling heating market. During the same period, residential heat demand shrunk by 33%, because metering of hot water consumption resulted in changing consumer habits, and because of slowly but step by step refurbishment of buildings and heating systems. In Hungary district heating is present in all large and most of the medium size cities, in 92 cities together. Out of them, there is also a single village with a local district heating system, which heats more than 60% of cottages. The capacity os systems is spreading to a large extent. Approximately 36-36% of all heated dwellings are in Budapest and in 10 large cities in the country, while 148 of the total 202 systems have less than 10 MW capacities. In the fuel structure of district heating it is characteristic the overwhelming role of natural gas consumption, which has exceeded 80% already. Only a few numbers of heating power plants are fuelled by crown coal. The use of renewables is growing continuous, but, together with waste and waste energy, it amounts merely 8% of the total fuel use. Oil consumption is negligible. Currently the most promising DH-market is the service sector (public buildings and commercial consumers). DH-companies can sell their surplus supply capacities on the competitive market. Residential market can be preserved only with better legal conditions and with improving of demand side management. The industrial heat market can be gained when the erection of new power plants will be harmonized with industrial development in the frame of territorial planning. District cooling is just at the beginning in Hungary. Many new commercial and office buildings are erected with air conditioning

  4. Heat recovery optimization in a steam-assisted gravity drainage (SAGD) plant

    International Nuclear Information System (INIS)

    Ashrafi, Omid; Navarri, Philippe; Hughes, Robin; Lu, Dennis

    2016-01-01

    Pinch Analysis was used to improve the energy performance of a typical steam-assisted gravity drainage (SAGD) process. The objective of this work was to reduce the amount of natural gas used for steam generation in the plant and the associated greenhouse gas emissions. The INTEGRATION software was used to analyze how heat is being used in the existing design and identify inefficient heat exchanges causing excessive use of energy. Several modifications to improve the base case heat exchanger network (HEN) were identified. The proposed retrofit projects reduced the process heating demands by improving the existing heat recovery system and by recovering waste heat and decreased natural gas consumption in the steam production unit by approximately 40 MW, representing approximately 8% of total consumption. As a result, the amount of glycol used to transfer energy across the facility was also reduced, as well as the electricity consumption related to glycol pumping. It was shown that the proposed heat recovery projects reduced natural gas costs by C$3.8 million/y and greenhouse gas emissions by 61,700 t/y of CO_2. - Highlights: • A heat integration study using Pinch analysis was performed in a SAGD process. • Several modifications are suggested to improve the existing heat recovery system. • Heat recovery projects increased boiler feed water and combustion air temperatures. • The proposed modifications reduced natural gas use for steam generation. • Heat recovery significantly reduced operating costs and greenhouse gas emissions.

  5. Is Swedish district heating operating on an integrated market? – Differences in pricing, price convergence, and marketing strategy between public and private district heating companies

    International Nuclear Information System (INIS)

    Åberg, M.; Fälting, L.; Forssell, A.

    2016-01-01

    The deregulation of the Swedish electricity market in 1996 made it possible to operate municipal district heating commercially. Until that time district heating had been organized mainly as municipal utilities. After 1996 district heating is instead expected to function on a market. In competitive and integrated markets, prices are expected to be equal, or converging. To find out if district heating operates on an integrated market the differences in price levels, price convergence, price strategy, and business goals, among municipal, private and state owned district heating companies are investigated. Price statistics was used along with results from a questionnaire that was answered by representatives for 109 Swedish district heating companies. The results show that prices among district heating systems do not converge significantly and that variations in prices among municipal systems are larger than among private and state owned systems. Furthermore, despite the fact that district heating is supposed to be commercial, a vast majority of district heating companies apply cost-based pricing and not market pricing. The municipal companies give priority to political goals before financial goals. The conclusion is that a Swedish integrated market for heat has not yet evolved, and some district heating price-controlling mechanism is necessary. - Highlights: • Price statistics and owner type data were used along with results from a questionnaire. • Results show that prices among district heating systems do not converge. • Municipal district heating companies still apply cost-based pricing to a large extent. • District heating companies are not operating on an integrated market for heat. • Some price-controlling mechanism for district heating is necessary.

  6. District Heating Network Design and Configuration Optimization with Genetic Algorithm

    DEFF Research Database (Denmark)

    Li, Hongwei; Svendsen, Svend

    2011-01-01

    In this paper, the configuration of a district heating (DH) network which connects from the heating plant to the end users was optimized with emphasizing the network thermal performance. Each end user in the network represents a building block. The locations of the building blocks are fixed while...... the heating plant location is allowed to vary. The connection between the heat generation plant and the end users can be represented with mixed integer and the pipe friction and heat loss formulations are non-linear. In order to find the optimal DH distribution pipeline configuration, the genetic algorithm...... by multi factors as the consumer heating load, the distance between the heating plant to the consumer, the design criteria regarding pressure and temperature limitation, as well as the corresponding network heat loss....

  7. Co-sponsored second quarter progress review conference on district heating

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-01-01

    A summary of the progress review conference on district heating and cooling systems is presented. The agenda and lists of speakers and attendees are presented. A history of district heating and some present needs and future policies are given and an excerpt from the National District Heating Program Strategy (DOE, March 1980) is included. Following the presentation, District Heating and Cooling Systems Program, by Alan M. Rubin, a fact sheet on DOE's Integrated Community Energy Systems Program and information from an oral presentation, District Heating and Cooling Systems for Communities Through Power Plant Retrofit Distribution Network, are given. The Second Quarterly Oral Report to the US DOE on the District Heating and Cooling Project in Detroit; the executive summary of the Piqua, Ohio District Heating and Cooling Demonstration Project; the Second Quarterly Report of the Moorehead, Minnesota District Heating Project; and the report from the Moorehead, Minnesota mayor on the Hot Water District Heating Project are presented.

  8. District heating with SLOWPOKE energy systems

    International Nuclear Information System (INIS)

    Lynch, G.F.

    1988-03-01

    The SLOWPOKE Energy System, a benign nuclear heat source designed to supply 10 thermal megawatts in the form of hot water for local heating systems in buildings and institutions, is at the forefront of these developments. A demonstration unit has been constructed in Canada and is currently undergoing an extensive test program. Because the nuclear heat source is small, operates at atmospheric pressure, and produces hot water below 100 degrees Celcius, intrinsic safety features will permit minimum operator attention and allow the heat source to be located close to the load and hence to people. In this way, a SLOWPOKE Energy System can be considered much like the oil- or coal-fired furnace it is designed to replace. The low capital investment requirements, coupled with a high degree of localization, even for the first unit, are seen as attractive features for the implementation of SLOWPOKE Energy Systems in many countries

  9. Simulation and analysis of main steam control system based on heat transfer calculation

    Science.gov (United States)

    Huang, Zhenqun; Li, Ruyan; Feng, Zhongbao; Wang, Songhan; Li, Wenbo; Cheng, Jiwei; Jin, Yingai

    2018-05-01

    In this paper, after thermal power plant 300MW boiler was studied, mat lab was used to write calculation program about heat transfer process between the main steam and boiler flue gas and amount of water was calculated to ensure the main steam temperature keeping in target temperature. Then heat transfer calculation program was introduced into Simulink simulation platform based on control system multiple models switching and heat transfer calculation. The results show that multiple models switching control system based on heat transfer calculation not only overcome the large inertia of main stream temperature, a large hysteresis characteristic of main stream temperature, but also adapted to the boiler load changing.

  10. Design of the steam reformer for the HTR-10 high temperature process heat application

    International Nuclear Information System (INIS)

    Ju Huaiming; Xu Yuanhui; Jia Haijun

    2000-01-01

    The 10 MW High Temperature Reactor Test Module (HTR-10) is being constructed now and planned to be operational in 2000. One of the objectives is to develop the high temperature process heat application. The methane steam reformer is one of the key-facilities for the nuclear process heat application system. The paper describes the conceptual design of the HTR-10 Steam Reformer with He heating, and the design optimization computer code. It can be used to perform sensitivity analysis for parameters, and to improve the design. Principal parameters and construction features of the HTR-10 reformer heated by He are introduced. (author)

  11. Physical limits on steam generation by radioactive decay heat

    International Nuclear Information System (INIS)

    Chesnut, D.A.

    1991-12-01

    This report briefly discusses the possibilities that flood water contacting the hot radioactive waste and rock at Yucca Mountain could produce enough steam to lift the top of the mountain off the repository

  12. Device for starting a steam generator by heating sodium in a reactor

    International Nuclear Information System (INIS)

    Nakano, Hisao.

    1975-01-01

    Object: To enhance cooperation between ventilation and steam conditions of turbine and ventilation condition relative to a superheater at the time of starting a plant using a fast breeder, and to enhance safety with respect to failure of heat transmission tubes at the time of start. Structure: In a device in which steam generated in an evaporator is fed to a high pressure turbine through a super-heater and an outlet steam of high pressure turbine is reheated by means of a re-heater and fed into a turbine on the side of low pressure to drive the turbine for power generation, opening and closing valves are mounted on outlet and inlet pipes, respectively, of the heat transmission pipe in the super heater, said outlet and inlet pipes being connected by a bypass pipe. Upstream side of the opening and closing valve on the inlet pipe and the downstream side of the opening and closing valve on the outlet pipe and connected by a bypass pipe in the re-heater and said bypass pipe in the re-heater is provided with a steam heat exchanger to be heated by steam in the outlet of the superheater, and a steam line in an auxiliary boiler is connected to the side of re-heater from the opening and closing valve on the heat transmission pipe in the re-heater. (Hanada, M.)

  13. The radiation safety assessment of the heating loop of district heating reactors

    International Nuclear Information System (INIS)

    Liu Yuanzhong

    1993-01-01

    The district heating reactors are used to supply heating to the houses in cities. The concerned problems are whether the radioactive materials reach the heated houses through heating loop, and whether the safety of the dwellers can be ensured. In order to prevent radioactive materials getting into the heated houses, the district heating reactors have three loops, namely, primary loop, intermediate loop, and heating loop. In the paper, the measures of preventing radioactive materials getting into the heating loop are presented, and the possible sources of the radioactivity in the water of the intermediate loop and the heating loop are given. The regulatory aim limit of radioactive concentration in the water of the intermediate loop is put forward, which is 18.5 Bq/l. Assuming that specific radioactivity of the water of contaminated intermediate loop is up to 18.5 Bq/l, the maximum concentration of radionuclides in water of the heating loop is calculated for the normal operation and the accident of district heating reactor. The results show that the maximum possible concentration is 5.7 x 10 -3 Bq/l. The radiation safety assessment of the heating loop is made out. The conclusions are that the district heating reactors do not bring any harmful impact to the dwellers, and the safety of the dwellers can be safeguarded completely

  14. Heat savings in buildings in a 100% renewable heat and power system in Denmark with different shares of district heating

    DEFF Research Database (Denmark)

    Zvingilaite, Erika; Balyk, Olexandr

    2014-01-01

    levels of heat savings, which can be implemented by reducing heat transmission losses through building elements and by installing ventilation systems with heat recovery, in different future Danish heat and power system scenarios. Today almost 50% of heat demand in Denmark is covered by district heating......The paper examines implementation of heat saving measures in buildings in 2050, under the assumption that heat and power supply comes solely from renewable resources in Denmark.Balmorel – a linear optimisation model of heat and power sectors in Denmark is used for investigating economically viable....... A further expansion of district heating network in Denmark is assessed and penetration of heat savings is analysed in this context.If all heat saving measures, included in the model, are implemented, heat demand in Danish buildings in 2050 could be reduced by around 40%. Results show that it is cost...

  15. Energy saving and emission reduction of China's urban district heating

    International Nuclear Information System (INIS)

    Chen, Xia; Wang, Li; Tong, Lige; Sun, Shufeng; Yue, Xianfang; Yin, Shaowu; Zheng, Lifang

    2013-01-01

    China's carbon dioxide (CO 2 ) emission ranks highest in the world. China is committed to reduce its CO 2 emission by 40% to 45% from the 2005 levels by 2020. To fulfill the target, China's CO 2 emission reduction must exceed 6995 million tons. Energy consumption and CO 2 emission of China's urban district heating (UDH) are increasing. The current policy implemented to improve UDH focuses on replacing coal with natural gas to reduce energy consumption and CO 2 emission to some extent. This paper proposes that heat pump heating (HPH) could serve as a replacement for UDH to help realize energy-saving and emission-reduction goals to a greater extent. The paper also analyzes the impact of this replacement on the heating and power generation sectors. The results show that replacing coal-based UDH with HPH decreases energy consumption and CO 2 emission by 43% in the heating sector. In the power generation sector, the efficiency of power generation at the valley electricity time increases by 0.512%, and the ratio of peak–valley difference decreases by 16.5%. The decreases in CO 2 emission from the heating and power generation sectors cumulatively account for 5.55% of China's total CO 2 emission reduction target in 2020. - Highlights: ► Replacing urban district heating with heat pump heating. ► Impact of heat pump heating on heating and power generation sectors. ► Potential of energy saving and emission reduction for heat pump heating. ► China should adjust current urban heating strategy

  16. Diagnostic system of steam generator, especially molten metal heated steam generator

    International Nuclear Information System (INIS)

    Matal, O.; Martoch, J.

    1986-01-01

    A diagnostic system is described and graphically represented consisting of a leak detector, a medium analyzer and sensors placed on the piping connected to the indication sections of both tube plates. The advantage of the designed system consists in the possibility of detecting tube failure immediately on leak formation, especially in generators with duplex tubes. This shortens the period of steam generator shutdown for repair and reduces power losses. The design also allows to make periodical leak tests during planned steam generator shutdowns. (A.K.)

  17. Impact of Next Generation District Heating Systems on Distribution Network Heat Losses: A Case Study Approach

    Science.gov (United States)

    Li, Yu; Rezgui, Yacine

    2018-01-01

    District heating (DH) is a promising energy pathway to alleviate environmental negative impacts induced by fossil fuels. Improving the performance of DH systems is one of the major challenges facing its wide adoption. This paper discusses the heat losses of the next generation DH based on the constructed Simulink model. Results show that lower distribution temperature and advanced insulation technology greatly reduce network heat losses. Also, the network heat loss can be further minimized by a reduction of heat demand in buildings.

  18. Quantitative thermography and methods for in-situ determination of heat losses from district heating networks

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, B. [ed.

    1996-11-01

    The course and seminar summarizing application of infrared thermography in district heating systems control gathered Danish specialists with 5 contributions on the subject. Maintenance of the heat distribution pipelines and thermographic inspection of the systems are essential in order to avoid heat losses. (EG)

  19. Low Temperature District Heating for Future Energy Systems

    DEFF Research Database (Denmark)

    Schmidt, Dietrich; Kallert, Anna; Blesl, Markus

    2017-01-01

    of the building stock. Low temperature district heating (LTDH) can contribute significantly to a more efficient use of energy resources as well as better integration of renewable energy (e.g. geothermal or solar heat), and surplus heat (e.g. industrial waste heat) into the heating sector. LTDH offers prospects......The building sector is responsible for more than one third of the final energy consumption of societies and produces the largest amount of greenhouse gas emissions of all sectors. This is due to the utilisation of combustion processes of mainly fossil fuels to satisfy the heating demand...... for both the demand side (community building structure) and the supply side (network properties or energy sources). Especially in connection with buildings that demand only low temperatures for space heating. The utilisation of lower temperatures reduces losses in pipelines and can increase the overall...

  20. Thermal performance of solar district heating plants in Denmark

    DEFF Research Database (Denmark)

    Furbo, Simon; Perers, Bengt; Bava, Federico

    2014-01-01

    The market for solar heating plants connected to district heating systems is expanding rapidly in Denmark. It is expected that by the end of 2014 the 10 largest solar heating plants in Europe will be located in Denmark. Measurements from 23 Danish solar heating plants, all based on flat plate solar...... collectors mounted on the ground, shows measured yearly thermal performances of the solar heating plants placed in the interval from 313 kWh/m² collector to 493 kWh/m² collector with averages for all plants of 411 kWh/m² collector for 2012 and 450 kWh/m² collector for 2013. Theoretical calculations show...... of the cost/performance ratio for solar collector fields, both with flat plate collectors and with concentrating tracking solar collectors. It is recommended to continue monitoring and analysis of all large solar heating plants to document the reliability of the solar heating plants. It is also recommended...

  1. Consumer Unit for Low Energy District Heating Net

    DEFF Research Database (Denmark)

    Paulsen, Otto; Fan, Jianhua; Furbo, Simon

    2008-01-01

    to reduce heat loss in the network. The consumer’s installation is a unit type with an accumulation tank for smoothing the heat load related to the domestic hot water. The building heat load is delivered by an under-floor heating system. The heavy under-floor heating system is assumed to smooth the room...... heat load on a daily basis, having a flow temperature control based on outdoor climate. The unit is designed for a near constant district heating water flow. The paper describes two concepts. The analyses are based on TRNSYS (Klein et al., 2006) simulation, supplied with laboratory verification......A low energy/ low temperature consumer installation is designed and analyzed. The consumer type is a low energy single family house 145 m2 with annual energy consumption in the range of 7000 kWh, incl. domestic hot water in a 2800 degree day climate. The network is an extreme low temperature system...

  2. Integration of Decentralized Thermal Storages Within District Heating (DH Networks

    Directory of Open Access Journals (Sweden)

    Schuchardt Georg K.

    2016-12-01

    Full Text Available Thermal Storages and Thermal Accumulators are an important component within District Heating (DH systems, adding flexibility and offering additional business opportunities for these systems. Furthermore, these components have a major impact on the energy and exergy efficiency as well as the heat losses of the heat distribution system. Especially the integration of Thermal Storages within ill-conditioned parts of the overall DH system enhances the efficiency of the heat distribution. Regarding an illustrative and simplified example for a DH system, the interactions of different heat storage concepts (centralized and decentralized and the heat losses, energy and exergy efficiencies will be examined by considering the thermal state of the heat distribution network.

  3. District heating grid of the Daqing Nuclear Heating Plant

    Energy Technology Data Exchange (ETDEWEB)

    Changwen, Ma [Institute of Nuclear Energy and Technology, Tsingua Univ., Beijing (China)

    1997-09-01

    The Daqing Nuclear Heating Plant is the first commercial heating plant to be built in China. The plant is planned to be used as the main heat resource of one residential quarter of Daqing city. The main parameters of the heating plant are summarized in the paper. The load curve shows that the capacity of the NHP is about 69% of total capacity of the grid. The 12 existing boilers can be used as reserve and peak load heat resources. Two patterns of load following have have been considered and tested on the 5MW Test Heating Reactor. Experiment shows load of heat grid is changed slowly, so automatic load following is not necessary. (author). 9 figs, 1 tab.

  4. District heating and cooling systems for communities through power plant retrofit distribution network. Final report, September 1, 1978-May 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-10-01

    This Final Report (Volume 2) of Phase 1 of District Heating for Communities Through Power Plant Retrofit Distribution Network contains 3 tasks: (1) Demonstration Team; (2) Identify Thermal Energy Sources and Potential Service Areas; and (3) Energy Market Analysis. Task 2 consists of estimating the thermal load within 5 and 10 miles of Public Service Electric and Gas Company steam power plants, Newark, New Jersey; estimating the costs of supplying thermal services to thermal loads of varying densities; a best case economic analysis of district heating for single-family homes; and some general comments on district-heating system design and development. Task 3 established the potential market for district heating that exists within a 5-mile radius of the selected generating stations; a sample of the questionnaire sent to the customers are shown. (MCW)

  5. Costs for district heating development. Status 2010; Kostnader for fjernvarmeutbygging. Status 2010

    Energy Technology Data Exchange (ETDEWEB)

    2010-12-15

    The report 'Costs of district heating development' presents the costs for district heating based on bioenergy primarily as base load. The report aims to be a tool for the heating developer to set up the investment budget and implement pilot projects. The project is funded by the Norwegian District Heating with support from Enova SF and implemented in close cooperation with the Norwegian district heating. (AG)

  6. Heat demand mapping and district heating grid expansion analysis: Case study of Velika Gorica

    Directory of Open Access Journals (Sweden)

    Dorotić Hrvoje

    2017-01-01

    Full Text Available Highly efficient cogeneration and district heating systems have a significant potential for primary energy savings and the reduction of greenhouse gas emissions through the utilization of a waste heat and renewable energy sources. These potentials are still highly underutilized in most European countries. They also play a key role in the planning of future energy systems due to their positive impact on the increase of integration of intermittent renewable energy sources, for example wind and solar in a combination with power to heat technologies. In order to ensure optimal levels of district heating penetration into an energy system, a comprehensive analysis is necessary to determine the actual demands and the potential energy supply. Economical analysis of the grid expansion by using the GIS based mapping methods hasn’t been demonstrated so far. This paper presents a heat demand mapping methodology and the use of its output for the district heating network expansion analysis. The result are showing that more than 59% of the heat demand could be covered by the district heating in the city of Velika Gorica, which is two times more than the present share. The most important reason of the district heating's unfulfilled potential is already existing natural gas infrastructure.

  7. Heat demand mapping and district heating grid expansion analysis: Case study of Velika Gorica

    Science.gov (United States)

    Dorotić, Hrvoje; Novosel, Tomislav; Duić, Neven; Pukšec, Tomislav

    2017-10-01

    Highly efficient cogeneration and district heating systems have a significant potential for primary energy savings and the reduction of greenhouse gas emissions through the utilization of a waste heat and renewable energy sources. These potentials are still highly underutilized in most European countries. They also play a key role in the planning of future energy systems due to their positive impact on the increase of integration of intermittent renewable energy sources, for example wind and solar in a combination with power to heat technologies. In order to ensure optimal levels of district heating penetration into an energy system, a comprehensive analysis is necessary to determine the actual demands and the potential energy supply. Economical analysis of the grid expansion by using the GIS based mapping methods hasn't been demonstrated so far. This paper presents a heat demand mapping methodology and the use of its output for the district heating network expansion analysis. The result are showing that more than 59% of the heat demand could be covered by the district heating in the city of Velika Gorica, which is two times more than the present share. The most important reason of the district heating's unfulfilled potential is already existing natural gas infrastructure.

  8. Heat transfer characteristics of horizontal steam generators under natural circulation conditions

    International Nuclear Information System (INIS)

    Hyvaerinen, J.

    1996-01-01

    This paper deals with the heat transfer characteristics of horizontal steam generators, particularly under natural circulation (decay heat removal) conditions on the primary side. Special emphasis is on the inherent features of horizontal steam generator behaviour. A mathematical model of the horizontal steam generator primary side is developed and qualitative results are obtained analytically. A computer code, called HSG, is developed to solve the model numerically, and its predictions are compared with experimental data. The code is employed to obtain for VVER 440 steam generators quantitative results concerning the dependence of primary-to-secondary heat transfer efficiency on the primary side flow rate, temperature and secondary level. It turns out that the depletion of the secondary inventory leads to an inherent limitation of the decay energy removal in VVER steam generators. The limitation arises as a consequence of the steam generator tube bundle geometry. As an example, it is shown that the grace period associated with pressurizer safety valve opening during a station black-out is 2 1/2-3 hours instead of the 5-6 hours reported in several earlier studies. (However, the change in core heat-up timing is much less-about 1 h at most.) The heat transfer limitation explains the fact that, in the Greifswald VVER 440 station black-out accident in 1975, the steam generators never boiled dry. In addition, the stability of single-phase natural circulation is discussed and insights on the modelling of horizontal steam generators with general-purpose thermal-hydraulic system codes are also presented. (orig.)

  9. A control model for district heating networks with storage

    NARCIS (Netherlands)

    Scholten, Tjeert; De Persis, Claudio; Tesi, Pietro

    2014-01-01

    In [1] pressure control of hydraulic networks is investigated. We extend this work to district heating systems with storage capabilities and derive a model taking the topology of the network into account. The goal for the derived model is that it should allow for control of the storage level and

  10. Benefits of Integrating Geographically Distributed District Heating Systems

    DEFF Research Database (Denmark)

    Dominkovic, Dominik Franjo; Bačeković, I.; Sveinbjörnsson, Dadi Þorsteinn

    2016-01-01

    Although liberalization of the electricity day-ahead markets has gained pace throughout the Europe, district heating markets are often dominated by lack of competition between suppliers, which curbs the potential of having cheaper systems in terms of socio-economic costs, and technically better s...

  11. Plug and Play Process Control of a District Heating System

    DEFF Research Database (Denmark)

    Trangbaek, Klaus; Knudsen, Torben; Skovmose Kallesøe, Carsten

    2009-01-01

    The main idea of plug and play process control is to initialise and reconfigure control systems automatically. In this paper these ideas are applied to a scaled laboratory model of a district heating pressure control system.  First of all this serves as a concrete example of plug and play control...

  12. Magneto-Inductive Underground Communications in a District Heating System

    DEFF Research Database (Denmark)

    Meybodi, Soroush Afkhami; Nielsen, Jens Frederik Dalsgaard; Bendtsen, Jan Dimon

    2011-01-01

    Feasibility of underground data communications is investigated by employing magnetic induction as the key technology at physical layer. Realizing an underground wireless sensor network for a district heating plant motivates this research problem. The main contribution of the paper is to find the ...

  13. Smart energy systems and 4th generation district heating

    DEFF Research Database (Denmark)

    Østergaard, Poul Alberg; Lund, Henrik; Mathiesen, Brian Vad

    2016-01-01

    of Sustainable Energy Planning and Management. The editorial and the volume presents work on district heating system scenarios in Austria, grid optimisation using genetic algorithms and finally design of energy scenarios for the Italian Alpine town Bressanone-Brixen from a smart energy approach. © 2016, Aalborg...

  14. Tritium permeation through helium-heated steam generators of ceramic breeder blankets for DEMO

    International Nuclear Information System (INIS)

    Fuetterer, M.A.; Raepsaet, X.; Proust, E.

    1994-01-01

    The specifications of permeation barriers, tritium recovery process maintaining a very low tritium activity in the coolant, and control of the coolant chemistry, required the evaluation of the tritium losses through the steam generators and include the definition of its operating conditions by thermodynamic cycle calculations and its thermal-hydraulic design. For both tasks specific computer tools were developed. The obtained geometry, surface area, and temperature profiles along the heat exchanger tubes were then used to estimate the daily tritium permeation into the steam cycle. Steam oxidized Incoloy 800 austenitic stainless steel was identified as the best suited existing material; in nominal steady-state operation, the tritium escape into the steam cycle could be restricted to less than 10 Ci/d. Tritium permeation during temperature and pressure transients in the steam generator (destruction and possible self-healing of the permeation barrier) is identified to bear a large tritium release potential. Solutions are proposed. (from authors). 4 figs., 1 tab

  15. Tritium permeation through helium-heated steam generators of ceramic breeder blankets for DEMO

    Energy Technology Data Exchange (ETDEWEB)

    Fuetterer, M A; Raepsaet, X; Proust, E

    1994-12-31

    The specifications of permeation barriers, tritium recovery process maintaining a very low tritium activity in the coolant, and control of the coolant chemistry, required the evaluation of the tritium losses through the steam generators and include the definition of its operating conditions by thermodynamic cycle calculations and its thermal-hydraulic design. For both tasks specific computer tools were developed. The obtained geometry, surface area, and temperature profiles along the heat exchanger tubes were then used to estimate the daily tritium permeation into the steam cycle. Steam oxidized Incoloy 800 austenitic stainless steel was identified as the best suited existing material; in nominal steady-state operation, the tritium escape into the steam cycle could be restricted to less than 10 Ci/d. Tritium permeation during temperature and pressure transients in the steam generator (destruction and possible self-healing of the permeation barrier) is identified to bear a large tritium release potential. Solutions are proposed. (from authors). 4 figs., 1 tab.

  16. Theoretical study on a multivariate feedback control of a sodium-heated steam generator

    International Nuclear Information System (INIS)

    Takahashi, R.; Maruyama, Y.; Oikawa, T.

    1984-01-01

    This paper applies the connection of a multivariate feedback controller with a state estimator to a 1-MW sodium-heated steam generator for LMFBR theoretically, to obtain a control strategy which emphasizes, from the view point of safety and availability of the FBR plant, that a superheat of 30 0 C should be required for the evaporator steam. This involves a trial to study the feasibility for the estimation of such an inaccessible variable as the dry-out location of tubes and utilize the state estimate to design a feedback controller of steam generators. The Kalman filter tested was found to generate reasonable estimates of the transient process variables of the steam generator and can provide a major advantage of regulating steam condition of the system even in the presence of contamination by a rather high level of measurement noise in the view point of economic uses of micro- and/or minicomputers. (orig.)

  17. Effect of heat transfer tube leak on dynamic characteristic of steam generator

    International Nuclear Information System (INIS)

    Sun Baozhi; Shi Jianxin; Li Na; Zheng Lusong; Liu Shanghua; Lei Yu

    2015-01-01

    Taking the steam generator of Daya Bay Nuclear Power Station as the research object, one-dimensional dynamic model of the steam generator based on drift flux theory and leak model of heat transfer tube were established. Steady simulation of steam generator under different conditions was carried out. Based on verifying the drift flux model and leak model of heat transfer tube, the effect of leak location and flow rate under different conditions on steam generator's key parameters was studied. The results show that the drift flux model and leak model can reflect the law of key parameter change accurately such as vapor mass fraction and steam pressure under different leak cases. The variation of the parameters is most apparent when the leak is at the entrance of boiling section and vapor mass fraction varies from 0.261 to 0.163 when leakage accounts for 5% of coolant flow rate. The successful prediction of the effect of heat transfer tube leak on dynamic characteristics of the steam generator based on drift flux theory supplies some references for monitoring and taking precautionary measures to prevent heat transfer tube leak accident. (authors)

  18. Condition monitoring of steam generator by estimating the overall heat transfer coefficient

    International Nuclear Information System (INIS)

    Furusawa, Hiroaki; Gofuku, Akio

    2013-01-01

    This study develops a technique for monitoring in on-line the state of the steam generator of the fast-breeder reactor (FBR) “Monju”. Because the FBR uses liquid sodium as coolant, it is necessary to handle liquid sodium with caution due to its chemical characteristics. The steam generator generates steam by the heat of secondary sodium coolant. The sodium-water reaction may happen if a pinhole or crack occurs at the thin metal tube wall that separates the secondary sodium coolant and water/steam. Therefore, it is very important to detect an anomaly of the wall of heat transfer tubes at an early stage. This study aims at developing an on-line condition monitoring technique of the steam generator by estimating overall heat transfer coefficient from process signals. This paper describes simplified mathematical models of superheater and evaporator to estimate the overall heat transfer coefficient and a technique to diagnose the state of the steam generator. The applicability of the technique is confirmed by several estimations using simulated process signals with artificial noises. The results of the estimations show that the developed technique can detect the occurrence of an anomaly. (author)

  19. Thermal analysis of heat and power plant with high temperature reactor and intermediate steam cycle

    Directory of Open Access Journals (Sweden)

    Fic Adam

    2015-03-01

    Full Text Available Thermal analysis of a heat and power plant with a high temperature gas cooled nuclear reactor is presented. The main aim of the considered system is to supply a technological process with the heat at suitably high temperature level. The considered unit is also used to produce electricity. The high temperature helium cooled nuclear reactor is the primary heat source in the system, which consists of: the reactor cooling cycle, the steam cycle and the gas heat pump cycle. Helium used as a carrier in the first cycle (classic Brayton cycle, which includes the reactor, delivers heat in a steam generator to produce superheated steam with required parameters of the intermediate cycle. The intermediate cycle is provided to transport energy from the reactor installation to the process installation requiring a high temperature heat. The distance between reactor and the process installation is assumed short and negligable, or alternatively equal to 1 km in the analysis. The system is also equipped with a high temperature argon heat pump to obtain the temperature level of a heat carrier required by a high temperature process. Thus, the steam of the intermediate cycle supplies a lower heat exchanger of the heat pump, a process heat exchanger at the medium temperature level and a classical steam turbine system (Rankine cycle. The main purpose of the research was to evaluate the effectiveness of the system considered and to assess whether such a three cycle cogeneration system is reasonable. Multivariant calculations have been carried out employing the developed mathematical model. The results have been presented in a form of the energy efficiency and exergy efficiency of the system as a function of the temperature drop in the high temperature process heat exchanger and the reactor pressure.

  20. Numerical study on steam injection in a turbocompound diesel engine for waste heat recovery

    International Nuclear Information System (INIS)

    Zhao, Rongchao; Li, Weihua; Zhuge, Weilin; Zhang, Yangjun; Yin, Yong

    2017-01-01

    Highlights: • Steam injection was adopted in a turbocompound engine to further recover waste heat. • Thermodynamics model for the turbocompound engine was established and calibrated. • Steam injection at CT inlet obtained lower engine BSFC than injection at PT inlet. • The optimal injected steam mass at different engine speeds was presented. • Turbocompounding combined with steam injection can reduce the BSFC by 6.0–11.2%. - Abstract: Steam injection and turbocompouding are both effective methods for engine waste heat recovery. The fuel saving potential obtained by the combination of the two methods is not clear. Based on a turbocompound engine developed in the previous study, the impacts of pre-turbine steam injection on the fuel saving potentials of the turbocompound engine were investigated in this paper. Firstly, thermodynamic cycle model for the baseline turbocompound engine is established using commercial software GT-POWER. The cycle model is calibrated with the experiment data of the turbocompound engine and achieves high accuracy. After that, the influences of steam mass flow rate, evaporating pressure and injection location on the engine performance are studied. In addition, the impacts of hot liquid water injection are also investigated. The results show that steam injection at the turbocharger turbine inlet can reduce the turbocompound engine BSFC at all speed conditions. The largest fuel reduction 6.15% is obtained at 1000 rpm condition. However, steam injection at power turbine inlet can only lower the BSFC at high speed conditions. Besides, it is found that hot liquid water injection in the exhaust cannot improve the engine performance. When compared with the conventional turbocharged engine, the combination of turbocompounding and steam injection can reduce the BSFC by 6.0–11.2% over different speeds.

  1. Make the heat hotter. - marketing district heating to households in detached houses

    Energy Technology Data Exchange (ETDEWEB)

    Sernhed, Kerstin; Pyrko, Jurek

    2008-09-15

    For district heating (DH) companies, to expand in low heat density areas such as detached houses, it is essential to obtain a high rate of connections to the district-heating network in order to enhance the cost effectiveness. Marketing district heating to house owners is, however, a fairly different matter from selling it to customers in industrial, commercial, and multi-family buildings. Suitable market strategies need to be developed and the need for information about potential customers' preferences and attitudes are of great importance since the house-owners often constitute a heterogeneous group where different households have different requirements. This paper investigates a case of one Swedish district heating company's marketing activities and expansion strategies in a single family house area where the customers were offered conversion of their direct resistive electric heating (DEH) into district heating (DH). 88 out of 111 houses were converted in 2002. Four years later, interviews were carried out with 23 of the households in the area, both with those who had accept-ed the district heating offer and those who had not. The study shows that apart from the economic aspects, thermal comfort, aesthetics and practicalities also affected the buying decision. Since the different economic aspects of the offer were complex, it was very difficult for the households to make a strictly rational economical decision. Statistical analysis confirmed that variables such as age, type of household and energy use level could, to some extent, be related to the decision to convert from electric heating to district heating. Timing, low prices and the total solutions presented to the households were crucial factors in the success of the marketing strategy.

  2. Method and apparatus for enhanced heat recovery from steam generators and water heaters

    Science.gov (United States)

    Knight, Richard A.; Rabovitser, Iosif K.; Wang, Dexin

    2006-06-27

    A heating system having a steam generator or water heater, at least one economizer, at least one condenser and at least one oxidant heater arranged in a manner so as to reduce the temperature and humidity of the exhaust gas (flue gas) stream and recover a major portion of the associated sensible and latent heat. The recovered heat is returned to the steam generator or water heater so as to increase the quantity of steam generated or water heated per quantity of fuel consumed. In addition, a portion of the water vapor produced by combustion of fuel is reclaimed for use as feed water, thereby reducing the make-up water requirement for the system.

  3. Radiation from Large Gas Volumes and Heat Exchange in Steam Boiler Furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Makarov, A. N., E-mail: tgtu-kafedra-ese@mail.ru [Tver State Technical University (Russian Federation)

    2015-09-15

    Radiation from large cylindrical gas volumes is studied as a means of simulating the flare in steam boiler furnaces. Calculations of heat exchange in a furnace by the zonal method and by simulation of the flare with cylindrical gas volumes are described. The latter method is more accurate and yields more reliable information on heat transfer processes taking place in furnaces.

  4. Lower pressure heating steam is practical for the distributed dry dilute sulfuric acid pretreatment.

    Science.gov (United States)

    Shao, Shuai; Zhang, Jian; Hou, Weiliang; Qureshi, Abdul Sattar; Bao, Jie

    2017-08-01

    Most studies paid more attention to the pretreatment temperature and the resulted pretreatment efficiency, while ignored the heating media and their scalability to an industry scale. This study aimed to use a relative low pressure heating steam easily provided by steam boiler to meet the requirement of distributed dry dilute acid pretreatment. The results showed that the physical properties of the pretreated corn stover were maintained stable using the steam pressure varying from 1.5, 1.7, 1.9 to 2.1MPa. Enzymatic hydrolysis and high solids loading simultaneous saccharification and fermentation (SSF) results were also satisfying. CFD simulation indicated that the high injection velocity of the low pressure steam resulted in a high steam holdup and made the mixing time of steam and solid corn stover during pretreatment much shorter in comparison with the higher pressure steam. This study provides a design basis for the boiler requirement in distributed pretreatment concept. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Steam generator design for solar towers using solar salt as heat transfer fluid

    Science.gov (United States)

    González-Gómez, Pedro Ángel; Petrakopoulou, Fontina; Briongos, Javier Villa; Santana, Domingo

    2017-06-01

    Since the operation of a concentrating solar power plant depends on the intermittent character of solar energy, the steam generator is subject to daily start-ups, stops and load variations. Faster start-up and load changes increase the plant flexibility and the daily energy production. However, it involves high thermal stresses on thick-walled components. Continuous operational conditions may eventually lead to a material failure. For these reasons, it is important to evaluate the transient behavior of the proposed designs in order to assure the reliability. The aim of this work is to analyze different steam generator designs for solar power tower plants using molten salt as heat transfer fluid. A conceptual steam generator design is proposed and associated heat transfer areas and steam drum size are calculated. Then, dynamic models for the main parts of the steam generator are developed to represent its transient performance. A temperature change rate that ensures safe hot start-up conditions is studied for the molten salt. The thermal stress evolution on the steam drum is calculated as key component of the steam generator.

  6. Integration of large-scale heat pumps in the district heating systems of Greater Copenhagen

    DEFF Research Database (Denmark)

    Bach, Bjarne; Werling, Jesper; Ommen, Torben Schmidt

    2016-01-01

    This study analyses the technical and private economic aspects of integrating a large capacity of electric driven HP (heat pumps) in the Greater Copenhagen DH (district heating) system, which is an example of a state-of-the-art large district heating system with many consumers and suppliers....... The analysis was based on using the energy model Balmorel to determine the optimum dispatch of HPs in the system. The potential heat sources in Copenhagen for use in HPs were determined based on data related to temperatures, flows, and hydrography at different locations, while respecting technical constraints...

  7. Steam generation device with heat exchange between a liquid metal coolant and the feedwater

    International Nuclear Information System (INIS)

    Malaval, C.

    1983-01-01

    The invention is particularly applicable to a liquid metal fast breeder reactor plant, the liquid metal being sodium. The steam generation device is described in detail, it allows to get an upper liquid metal level without turbulence and an easier passage for the shock wave towards the steam generator up to the liquid metal level without being laterally reflected back to the intermediate heat exchangers [fr

  8. Low Temperature District Heating Consumer Unit with Micro Heat Pump for Domestic Hot Water Preparation

    DEFF Research Database (Denmark)

    Zvingilaite, Erika; Ommen, Torben Schmidt; Elmegaard, Brian

    2012-01-01

    In this paper we present and analyse the feasibility of a district heating (DH) consumer unit with micro heat pump for domestic hot water (DHW) preparation in a low temperature (40 °C) DH network. We propose a micro booster heat pump of high efficiency (COP equal to 5,3) in a consumer DH unit...... in order to boost the temperature of the district heating water for heating the DHW. The paper presents the main designs of the suggested system and different alternative micro booster heat pump concepts. Energy efficiency and thermodynamic performance of these concepts are calculated and compared....... The results show that the proposed system has the highest efficiency. Furthermore, we compare thermodynamic and economic performance of the suggested heat pump-based concept with different solutions, using electric water heater. The micro booster heat pump system has the highest annualised investment (390 EUR...

  9. The Thermos program for nuclear reactors specialized in district heating

    International Nuclear Information System (INIS)

    Lerouge, B.

    1976-01-01

    Many studies have been made in France on the use of nuclear heat for district heating. After a brief account of the problems raised by the use of thermal waste from big nuclear power stations, the quantitative and qualitative needs of heating networks are analyzed and the Thermos project described. This is a very robust reactor of the pool type, with an output of 100MW, supplying low-pressure water at 100 deg C. The advantages from the aspects of safety and economy are described, and the present state of the project and its possible developments summarized [fr

  10. Biomass gasification in district heating systems - The effect of economic energy policies

    International Nuclear Information System (INIS)

    Wetterlund, Elisabeth; Soederstroem, Mats

    2010-01-01

    Biomass gasification is considered a key technology in reaching targets for renewable energy and CO 2 emissions reduction. This study evaluates policy instruments affecting the profitability of biomass gasification applications integrated in a Swedish district heating (DH) system for the medium-term future (around year 2025). Two polygeneration applications based on gasification technology are considered in this paper: (1) a biorefinery plant co-producing synthetic natural gas (SNG) and district heat; (2) a combined heat and power (CHP) plant using integrated gasification combined cycle technology. Using an optimisation model we identify the levels of policy support, here assumed to be in the form of tradable certificates, required to make biofuel production competitive to biomass based electricity generation under various energy market conditions. Similarly, the tradable green electricity certificate levels necessary to make gasification based electricity generation competitive to conventional steam cycle technology, are identified. The results show that in order for investment in the SNG biorefinery to be competitive to investment in electricity production in the DH system, biofuel certificates in the range of 24-42 EUR/MWh are needed. Electricity certificates are not a prerequisite for investment in gasification based CHP to be competitive to investment in conventional steam cycle CHP, given sufficiently high electricity prices. While the required biofuel policy support is relatively insensitive to variations in capital cost, the required electricity certificates show high sensitivity to variations in investment costs. It is concluded that the large capital commitment and strong dependency on policy instruments makes it necessary that DH suppliers believe in the long-sightedness of future support policies, in order for investments in large-scale biomass gasification in DH systems to be realised.

  11. Technoeconomic analysis of a biomass based district heating system. Paper no. IGEC-1-ID01

    International Nuclear Information System (INIS)

    Zhang, H.; Ugursal, V.I.; Fung, A.

    2005-01-01

    District energy systems (DES) that produce steam, hot water or chilled water at a central plant and then distribute that energy to buildings in the district for space heating, domestic hot water heating and air conditioning provide opportunities for increasing energy efficiency and reducing greenhouse gas (GHG) emissions. Use of biomass, such as wood, wood byproducts and wastes, fast-growing trees, agricultural crops and waste, in place of conventional fossil fuels to produce the thermal energy needed by a DES, presents further opportunities for reducing green house gas emissions as well as providing rural employment, and local solutions to rural and remote energy needs. In this paper, a technoeconomic analysis of a biomass based DES for a community center in Nova Scotia, Canada is presented. The methodology used to size and design the heating and ventilating system, as well as the biomass based DES is discussed. Annual energy requirement and biomass fuel consumption predictions are presented along with cost estimates. A comparative assessment of the economic feasibility of the system vis-a-vis a conventional oil fired system is conducted. While the results are specific to the particular application, the design and analysis methodology that is presented in the paper can be used for any similar application. (author)

  12. Energetic and exergetic efficiencies of coal-fired CHP (combined heat and power) plants used in district heating systems of China

    International Nuclear Information System (INIS)

    Liao, Chunhui; Ertesvåg, Ivar S.; Zhao, Jianing

    2013-01-01

    The efficiencies of coal-fired CHP (combined heat and power) plants used in the district heating systems of China were analyzed with a thermodynamic model in the Hysys program. The influences of four parameters were evaluated by the Taguchi method. The results indicated that the extraction steam flow rate and extraction steam pressure are the most important parameters for energetic and exergetic efficiencies, respectively. The relations between extraction steam flow rate, extraction steam pressure and the energetic and exergetic efficiencies were investigated. The energetic and exergetic efficiencies were compared to the RPES (relative primary energy savings) and the RAI (relative avoided irreversibility). Compared to SHP (separate heat and power) generation, the CHP systems save fuel energy when extraction ratio is larger than 0.15. In the analysis of RAI, the minimum extraction ratio at which CHP system has advantages compared with SHP varies between 0.25 and 0.6. The higher extraction pressure corresponds to a higher value. Two of the examined plants had design conditions giving RPES close to zero and negative RAI. The third had both positive RPES and RAI at design conditions. The minimum extraction ratio can be used as an indicator to design or choose CHP plant for a given district heating system. - Highlights: • Extraction flow rate and extraction pressure are the most important parameters. • The exergetic efficiency depends on the energy to exergy ratio and system boundary. • The minimum extraction ratio is a key indicator for CHP plants. • Program Hysys and Taguchi method are used in this research

  13. Protein denaturation and functional properties of Lenient Steam Injection heat treated whey protein concentrate

    DEFF Research Database (Denmark)

    Dickow, Jonatan Ahrens; Kaufmann, Niels; Wiking, Lars

    2012-01-01

    Whey protein concentrate (WPC) was heat treated by use of the novel heat treatment method of Lenient Steam Injection (LSI) to elucidate new functional properties in relation to heat-induced gelation of heat treated WPC. Denaturation was measured by both DSC and FPLC, and the results of the two...... methods were highly correlated. Temperatures of up to 90 °C were applicable using LSI, whereas only 68 °C could be reached by plate heat exchange before coagulation/fouling. Denaturation of whey proteins increased with increasing heat treatment temperature up to a degree of 30–35% denaturation at 90 °C...

  14. Active latent heat storage with a screw heat exchanger - experimental results for heat transfer and concept for high pressure steam

    Science.gov (United States)

    Zipf, Verena; Willert, Daniel; Neuhäuser, Anton

    2016-05-01

    An innovative active latent heat storage concept was invented and developed at Fraunhofer ISE. It uses a screw heat exchanger (SHE) for the phase change during the transport of a phase change material (PCM) from a cold to a hot tank or vice versa. This separates heat transfer and storage tank in comparison to existing concepts. A test rig has been built in order to investigate the heat transfer coefficients of the SHE during melting and crystallization of the PCM. The knowledge of these characteristics is crucial in order to assess the performance of the latent heat storage in a thermal system. The test rig contains a double shafted SHE, which is heated or cooled with thermal oil. The overall heat transfer coefficient U and the convective heat transfer coefficient on the PCM side hPCM both for charging and discharging have been calculated based on the measured data. For charging, the overall heat transfer coefficient in the tested SHE was Uch = 308 W/m2K and for discharging Udis = 210 W/m2K. Based on the values for hPCM the overall heat transfer coefficients for a larger SHE with steam as heat transfer fluid and an optimized geometry were calculated with Uch = 320 W/m2K for charging and Udis = 243 W/m2K for discharging. For pressures as high as p = 100 bar, an SHE concept has been developed, which uses an organic fluid inside the flight of the SHE as working media. With this concept, the SHE can also be deployed for very high pressure, e.g. as storage in solar thermal power plants.

  15. Steady-state heat transfer in an inverted U-tube steam generator

    International Nuclear Information System (INIS)

    Boucher, T.J.

    1987-01-01

    Experimental results are presented involving U-tube steam generator tube bundle local heat transfer and fluid conditions during stead-state, full-power operations performed at high temperatures and pressures with conditions typical of a pressurized water reactor (15.0 MPa primary pressure, 600 K steam generator inlet plenum fluid temperatures, 6.2 MPa secondary pressure). The Semiscale (MOD-2C facility represents the state-of-the-art in measurement of tube local heat transfer data and average tube bundle secondary fluid density at several elevations, which allows an estimate of the axial heat transfer and void distributions during steady-state and transient operations. The method of heat transfer data reduction is presented and the heat flux, secondary convective heat transfer coefficient, and void fraction distributions are quantified for steady-state, full-power operations

  16. District Heating in Areas with Low Energy Houses

    DEFF Research Database (Denmark)

    Tol, Hakan Ibrahim

    -energy houses involved, together with the idea of utilizing booster pumps in the district heating network and (ii) use of network layouts of either a branched (tree-like) or a looped type. The methods developed were applied in a case study, the data of which was provided by the municipality of Roskilde...... in Denmark. The second case study was aimed at solving another regional energy planning scheme, one concerned with already existing houses, the heat requirements of which were currently being met by use of a natural gas grid or a conventional high-temperature district heating network. The idea considered......This PhD thesis presents a summary of a three-year PhD project involving three case studies, each pertaining to a typical regional Danish energy planning scheme with regard to the extensive use of low-energy district heating systems, operating at temperatures as low as 55°C for supply and 25°C...

  17. Performance of ultra low temperature district heating systems with utility plant and booster heat pumps

    DEFF Research Database (Denmark)

    Ommen, Torben Schmidt; Thorsen, Jan Eric; Markussen, Wiebke Brix

    2017-01-01

    The optimal integration of booster heat pumps in ultra low temperature district heating (ULTDH) was investigated and compared to the performance of low temperature district heating. Two possible heat production technologies for the DH networks were analysed, namely extraction combined heat...... temperature and the heat consumption profile. For reference conditions, the optimal return of ULTDH varies between 21 °C and 27 °C. When using a central HP to supply the DH system, the resulting coefficient of system performance (COSP) was in the range of 3.9 (-) to 4.7 (-) for equipment with realistic...... component efficiencies and effectiveness, when including the relevant parameters such as DH system pressure and heat losses. By using ULTDH with booster HPs, performance improvements of 12% for the reference calculations case were found, if the system was supplied by central HPs. Opposite results were found...

  18. Returns and solvency in the Norwegian district heating sector 2010; Avkastning og soliditet i fjernvarmebransjen 2010

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    On behalf of Enova Pareto conducted an analysis of returns and solvency in the district heating sector for fiscal years 2009 and 2010. The analysis focuses on a representative sample of the largest district heating companies in Norway. A total of 26 companies have been analyzed. These companies provide a total of ~ 80% of the district heating in Norway. (eb)

  19. Interfacial condensation heat transfer for countercurrent steam-water wavy flow in a horizontal circular pipe

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Won; Chun, Moon Hyun [Korea Advanced Institute of Science and Technolgy, Taejon (Korea, Republic of); Chu, In Cheol [KAERI, Taejon (Korea, Republic of)

    2000-10-01

    An experimental study of interfacial condensation heat transfer has been performed for countercurrent steam-water wavy flow in a horizontal circular pipe. A total of 105 local interfacial condensation heat transfer coefficients have been obtained for various combinations of test parameters. Two empirical Nusselt number correlations were developed and parametric effects of steam and water flow rates and the degree of water subcooling on the condensation heat transfer were examined. For the wavy interface condition, the local Nusselt number is more strongly sensitive to the steam Reynolds number than water Reynolds number as opposed to the case of smooth interface condition. Comparisons of the present circular pipe data with existing correlations showed that existing correlations developed for rectangular channels are not directly applicable to a horizontal circular pipe flow.

  20. Enrichment of water solube substances at heat transfer surfaces in steam boilers and steam generators - a literature survey

    International Nuclear Information System (INIS)

    Kelen, T.

    1975-03-01

    A literature survey has been made to determine the possible need for investigations into enrichment at heat transport surfaces. The survey shows that enrichment in furnace tubes of carbon steel has led both to hydrogen embrittlement as a result of a reduction of pH and to local tube wall thinning and alkaline stress corrosion following an increase of pH. Damage caused by enrichment has occurred also in the steam generators of PWR's. Information concerning measured enrichment, observed hide-out, occurrence of normally easily soluble deposits as well as of corrosion damage requiring high concentrations lead to the conclusion that enrichment factors of the order of 10 000 are to be expected in some instances. The relationship between operational conditions and enrichment in specific cases is, however, poorly documented. The tendency to hide out varies for different substances. This is however not evidently equivalent to variation of the corresponding enrichment factor in the solution. Enrichment at heat transfer surfaces can arise as the result of one or several of the following effects: - formation of porous deposits - poor circulation - high densities of heat flow rate - departure from nucleate boiling leading to dry-out - steam blanketing. The conclusion reached from the literature survey is that knowledge of the degree of enrichment produced under specific operational conditions is extremely inadequate. (author)

  1. Geothermal district heating system feasibility analysis, Thermopolis, Wyoming

    Energy Technology Data Exchange (ETDEWEB)

    Goering, S.W.; Garing, K.L.; Coury, G.; Mickley, M.C.

    1982-04-26

    The purpose of this study is to determine the technical and economic feasibility of constructing and operating a district heating system to serve the residential, commercial, and public sectors in Thermopolis. The project geothermal resource assessment, based on reviews of existing information and data, indicated that substantial hot water resources likely exist in the Rose Dome region 10 miles northeast of Thermopolis, and with quantities capable of supporting the proposed geothermal uses. Preliminary engineering designs were developed to serve the space heating and hot water heating demands for buildings in the Thermopolis-East Thermopolis town service area. The heating district design is based on indirect geothermal heat supply and includes production wells, transmission lines, heat exchanger units, and the closed loop distribution and collection system necessary to serve the individual customers. Three options are presented for disposal of the cooled waters-reinjection, river disposal, and agricultural reuse. The preliminary engineering effort indicates the proposed system is technically feasible. The design is sized to serve 1545 residences, 190 businesses, and 24 public buildings. The peak design meets a demand of 128.2 million Btu at production rates of 6400 gpm.

  2. Qualification of Alloy 800 for sodium heated steam generators

    International Nuclear Information System (INIS)

    Duke, J.M.; Sessions, C.E.; Ray, W.E.

    1976-01-01

    A reference specification of Alloy 800 for use in LMFBR steam generators is defined considering waterside corrosion, weldability and mechanical properties. Additional mechanical test data are being generated to support ASME Code acceptance. Candidate weld filler metals were assessed for use in subsequent weld process development. Progress on resolving technical concerns related to the role of tertiary creep identified the impact of test conditions and gamma prime strengthening in determining the creep behavior of Alloy 800

  3. Accident alarm equipment for steam generator, especially liquid sodium heated steam generator

    International Nuclear Information System (INIS)

    Matal, O.; Jung, J.; Banovec, J.

    1982-01-01

    The alarm equipment consists of a system of sensors mounted onto the steam generator and its accessories. Each of the sensors is used for a different accident characteristic, such as the flow of sodium, the acoustic spectrum, the concentration of hydrogen in sodium. The system of sensors is connected to the common accident alarm system. The equipment will not issue the alarm signal if it receives a message from only one sensor, only when the message is confirmed from other sensors. This excludes false alarm. (M.D.)

  4. Exergetic evaluation of heat pump booster configurations in a low temperature district heating network

    DEFF Research Database (Denmark)

    Ommen, Torben Schmidt; Elmegaard, Brian

    2012-01-01

    In order to minimise losses in a district heating network, one approach is to lower the temperature difference between working media and soil. Considering only direct heat exchange, the minimum forward temperature level is determined by the demand side, as energy services are required at a certai...

  5. Steady-state heat losses in pipes for low-energy district heating

    DEFF Research Database (Denmark)

    Dalla Rosa, Alessandro; Li, Hongwei; Svendsen, Svend

    2010-01-01

    The synergy between highly energy efficient buildings and low-energy district heating (DH) systems is a promising concept for the optimal integration of energy saving policies and energy supply systems based on renewable energy (RE). Distribution heat losses represent a key factor in the design o...

  6. Numerical investigation of passive heat removal system via steam generator in VVER 1200

    International Nuclear Information System (INIS)

    Dinh Anh Tuan; Duong Thanh Tung; Tran Chi Thanh; Nguyen Van Thai

    2015-01-01

    Passive heat removal system (PHRS) via Steam Generator is an important part in VVER design. In case of Design Basic Accidents such as blackout, failure of feed water supply to steam generator or coolant leakage with failure of emergency core cooling at high pressure. PHRS is designed to remove the residual heat from reactor core through steam generator to heat exchanger which is placed outside reactor vessel. In order to evaluate the passive system, a numerical investigation using a CFD code is performed. However, PHRS has complex geometry for using CFD simulation. Thus, RELAP5 is applied to provide the wall heat flux of tube in the heat exchanger tank. The natural convection in the heat exchanger tank is investigated in this report. Numerical results show temperature and velocity distribution in the heat exchanger tank are calculated with different wall heat flux corresponding to various transient conditions. The calculated results contribute to the capacity analysis of passive heat removal system and giving valuable information for safe operation of VVER 1200. (author)

  7. The application of ground source heat pumps to a subdivision-wide district heating system

    International Nuclear Information System (INIS)

    Ciavaglia, L.

    2005-01-01

    Design guidelines for economic ground source heat pumps (GSHP) in district energy systems were presented. The broad economics of using central GSHP in a community district energy system were examined. Design parameters needed to utilize GSHP in district energy system were outlined. The sensitivity of energy prices and the costs of major capital were reviewed. District heating load duration curves were outlined. It was suggested that varying GSHP capacity from 0 to 100 per cent of load was advisable. In addition, capacity should be balanced with gas boiler technology. The amortizing of capital within energy costs was recommended. It was suggested that the best scenario was a minimum of 50 per cent ground energy. Details of pipings and heat exchanger costs were presented, along with costs for gas boilers and gas costs for the district energy system. Charts of current costing and reduction of piping capital were included. It was concluded that GSHP can be a viable component of a district energy system, as a GSHP based district energy system can provide more stable energy prices than conventional fossil fuel systems. It was suggested that sizing of GSHP at, or near, 40 per cent of peak demand provided optimal conditions with respect to energy cost and use of earth energy. tabs., figs

  8. Feasibility analysis of geothermal district heating for Lakeview, Oregon

    Energy Technology Data Exchange (ETDEWEB)

    1980-12-23

    An analysis of the geothermal resource at Lakeview, Oregon, indicates that a substantial resource exists in the area capable of supporting extensive residential, commercial and industrial heat loads. Good resource productivity is expected with water temperatures of 200{degrees}F at depths of 600 to 3000 feet in the immediate vicinity of the town. Preliminary district heating system designs were developed for a Base Case serving 1170 homes, 119 commercial and municipal buildings, and a new alcohol fuel production facility; a second design was prepared for a downtown Mini-district case with 50 commercial users and the alcohol plant. Capital and operating costs were determined for both cases. Initial development of the Lakeview system has involved conducting user surveys, well tests, determinations of institutional requirements, system designs, and project feasibility analyses. A preferred approach for development will be to establish the downtown Mini-district and, as experience and acceptance are obtained, to expand the system to other areas of town. Projected energy costs for the Mini-district are $10.30 per million Btu while those for the larger Base Case design are $8.20 per million Btu. These costs are competitive with costs for existing sources of energy in the Lakeview area.

  9. Steam generators and waste heat boilers for process and plant engineers

    CERN Document Server

    Ganapathy, V

    2014-01-01

    Incorporates Worked-Out Real-World ProblemsSteam Generators and Waste Heat Boilers: For Process and Plant Engineers focuses on the thermal design and performance aspects of steam generators, HRSGs and fire tube, water tube waste heat boilers including air heaters, and condensing economizers. Over 120 real-life problems are fully worked out which will help plant engineers in evaluating new boilers or making modifications to existing boiler components without assistance from boiler suppliers. The book examines recent trends and developments in boiler design and technology and presents novel idea

  10. Studies and solutions of steam turbines for nuclear heating power stations

    International Nuclear Information System (INIS)

    Drahy, J.

    1979-01-01

    The possibilities of combined generation of heat and electric power and special features of the corresponding equipment for WWER type reactors are considered. Condensing steam turbines with bled steam points and the constructional solution of bled points are presented for heating the network water to 110 0 C, 120 0 C, and 160 0 C, respectively. The dimensions of the low pressure final stage of the turbine are given. Problems concerning condensing and bleeding turbines and combination types of back-pressure and condensing turbines as well as solutions to the design of 250 MW and 500 MW turbines are discussed

  11. Evaluation of piping heat transfer, piping flow regimes, and steam generator heat transfer for the Semiscale Mod-1 isothermal tests

    International Nuclear Information System (INIS)

    French, R.T.

    1975-08-01

    Selected experimental data pertinent to piping heat transfer, transient fluid flow regimes, and steam generator heat transfer obtained during the Semiscale Mod-1 isothermal blowdown test series (Test Series 1) are analyzed. The tests in this first test series were designed to provide counterparts to the LOFT nonnuclear experiments. The data from the Semiscale Mod-1 intact and broken loop piping are evaluated to determine the surface heat flux and average heat transfer coefficients effective during the blowdown transient and compared with well known heat transfer correlations used in the RELAP4 computer program. Flow regimes in horizontal pipe sections are calculated and compared with data obtained from horizontal and vertical densitometers and with an existing steady state flow map. Effects of steam generator heat transfer are evaluated quantitatively and qualitatively. The Semiscale Mod-1 data and the analysis presented in this report are valuable for evaluating the adequacy and improving the predictive capability of analytical models developed to predict system response to piping heat transfer, piping flow regimes, and steam generator heat transfer during a postulated loss-of-coolant accident (LOCA) in a pressurized water reactor (PWR). 16 references. (auth)

  12. Online, real-time corrosion monitoring in district heating systems

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Thorarinsdottir, R.I.

    2005-01-01

    The corrosion control in district heating systems is today performed primarily with control of the water quality. The corrosion rate is kept low by assuring low dissolved oxygen concentration, high pH and low conductivity. Corrosion failures can occur, e.g. as a result of unknown oxygen ingress, ......, precipitation of deposits or crevices. The authors describe methods used for on-line monitoring of corrosion, cover the complications and the main results of a Nordic project.......The corrosion control in district heating systems is today performed primarily with control of the water quality. The corrosion rate is kept low by assuring low dissolved oxygen concentration, high pH and low conductivity. Corrosion failures can occur, e.g. as a result of unknown oxygen ingress...

  13. On-line Corrosion Monitoring in District Heating Systems

    DEFF Research Database (Denmark)

    Richter, Sonja; Thorarinsdottir, R.I.; Hilbert, Lisbeth Rischel

    2005-01-01

    The corrosion control in district heating systems is today performed primarily with control of the water quality. The corrosion rate is kept low by assuring low dissolved oxygen concentration, high pH and low conductivity. Corrosion failures can occur, e.g. as a result of unknown oxygen ingress, ......, precipitation of deposits or crevices. The authors describe methods used for on-line monitoring of corrosion, cover the complications and the main results of a Nordic project.......The corrosion control in district heating systems is today performed primarily with control of the water quality. The corrosion rate is kept low by assuring low dissolved oxygen concentration, high pH and low conductivity. Corrosion failures can occur, e.g. as a result of unknown oxygen ingress...

  14. Dynamic behavior of district heating systems. 2. User's guide

    International Nuclear Information System (INIS)

    Kunz, J.

    1993-01-01

    This user's guide consists of three parts. The first part describes the characteristics and performance of the dynamic simulation code for district heating systems DYNAM. It shows how to prepare a personal computer for this program and how to install it. The second part shows how to prepare the data for a simulation and how to use the simulation program. Those two sections are for the user who intends to use the code for the simulation of district heating systems. He also learns to prepare the necessary data for his specific problems. The third section is intended for the programmer who desires to improve the program. It explains the main calculation units and shows the parts of the program which seem most important for an improvement. (author) 4 figs

  15. Dynamic behavior of district heating systems. 1. Report

    International Nuclear Information System (INIS)

    Kunz, J.

    1993-01-01

    In this study a comprehensive model simulating the dynamic behavior of an entire district heating system has been developed. The model consists of four partial models, namely a model of the hydraulic behavior of a heat distribution network, another model of the thermal behavior of this network, a model of the heat generation plants and one of the heat consumers connected to the system. For the hydraulic simulation of the distribution network, a classical steady state approach has proved to be sufficient. The evolution of the temperatures in the network is given by the equation of transport. A numerical resolution scheme, which is adapted to the special case of a heat distribution network was developed for this equation. The model developed for the heating plant is simple but it is sufficiently detailed to determine the operation of its elements. A more complex model would take much more calculation time, but with such a simple model, it is possible to include it in the global model of the entire system. Each heat consumer is represented by a simple one cell model. The difficulty in such an approach is to determine the characteristics of each building in a simple manner. A classification, which allows to find the essential parameters from few and easily available data, has been defined. This model is not sufficiently accurate to calculate the thermal behavior of one specific building but it allows to determine the average dynamic evolution of the heat demand for a set of buildings with a good precision.The developed models have been programmed on a personal computer and the entire district heating network of the city of Lausanne has been simulated with this calculation code. Measurements have been taken on this network and the comparison with calculated results has allowed to calibrate the model. The comparison of measurements and calculations shows, that each part of the system is simulated realistically by the proposed model. (author) figs., tabs., refs

  16. Straw fired district heating plants in Denmark. Facts and figures

    International Nuclear Information System (INIS)

    1996-05-01

    A series of analyses and comparisons of technical, operational and financial and environmental conditions relating to straw-fired district heating and cogeneration plants in Denmark during the period of May 1993 to June 1995. The report provides an insight into the potentials of straw as a source of energy, particularly in the case of countries where the cultivation of cereals represents a major part of the agricultural economy. (AB)

  17. Geothermal district heating in Turkey: The Gonen case study

    International Nuclear Information System (INIS)

    Oktay, Zuhal; Aslan, Asiye

    2007-01-01

    The status of geothermal district heating in Turkey and its future prospects are reviewed. A description is given of the Gonen project in Balikesir province, the first system to begin citywide operation in the country. The geology and geothermal resources of the area, the history of the project's development, the problems encountered, its economic aspects and environmental contributions are all discussed. The results of this and other such systems installed in Turkey have confirmed that, in this country, heating an entire city based on geothermal energy is a significantly cleaner, cheaper option than using fossil fuels or other renewable energy resources. (author)

  18. Exergoeconomic analysis of geothermal district heating systems: A case study

    International Nuclear Information System (INIS)

    Ozgener, Leyla; Hepbasli, Arif; Dincer, Ibrahim; Rosen, Marc A.

    2007-01-01

    An exergoeconomic study of geothermal district heating systems through mass, energy, exergy and cost accounting analyses is reported and a case study is presented for the Salihli geothermal district heating system (SGDHS) in Turkey to illustrate the present method. The relations between capital costs and thermodynamic losses for the system components are also investigated. Thermodynamic loss rate-to-capital cost ratios are used to show that, for the devices and the overall system, a systematic correlation appears to exist between capital cost and exergy loss (total or internal), but not between capital cost and energy loss or external exergy loss. Furthermore, a parametric study is conducted to determine how the ratio of thermodynamic loss rate to capital cost changes with reference temperature and to develop a correlation that can be used for practical analyses. The correlations may imply that devices in successful district heating systems such as the SGDHS are configured so as to achieve an overall optimal design, by appropriately balancing the thermodynamic (exergy-based) and economic (cost) characteristics of the overall systems and their devices

  19. A multicriteria approach to evaluate district heating system options

    Energy Technology Data Exchange (ETDEWEB)

    Ghafghazi, S.; Sowlati, T. [Department of Wood Science, University of British Columbia, 2931-2424 Main Mall, Vancouver, BC (Canada); Sokhansanj, S. [Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, BC (Canada); Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Melin, S. [Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, BC (Canada); Delta Research Corporation, Delta, BC (Canada)

    2010-04-15

    District energy systems, in which renewable energy sources may be utilized, are centralized systems to provide energy to residential and commercial buildings. The aim of this paper is to evaluate and rank energy sources available for a case of district heating system in Vancouver, Canada, based on multiple criteria and the view points of different stakeholders, and to show how communication would affect the ranking of alternatives. The available energy sources are natural gas, biomass (wood pellets), sewer heat, and geothermal heat. The evaluation criteria include GHG emissions, particulate matter emissions, maturity of technology, traffic load, and local source. In order to rank the energy options the PROMETHEE method is used. In this paper, two different scenarios were developed to indicate how the communication between the stakeholders would affect their preferences about criteria weights and would change the ranking of alternatives. The result of this study shows that without communication the best energy source for the considered district energy system is different for different stakeholders. While, addressing concerns through efficient communication would result in a general consensus. In this case, wood pellet is the best energy alternative for all the stakeholders. (author)

  20. Investigation of In-Cylinder Steam Injection in a Turbocharged Diesel Engine for Waste Heat Recovery and NOx Emission Control

    OpenAIRE

    Zhongbo Zhang; Lifu Li

    2018-01-01

    In this study, an in-cylinder steam injection method is introduced and applied to a turbocharged diesel engine for waste heat recovery and NOx emission reduction. In the method, cool water was first heated into superheated steam by exhaust. Then the superheated steam was directly injected into the cylinder during the compression stroke. The potential for fuel savings and NOx emission reduction obtained by this method was investigated. First, a two-zone combustion model for the baseline engine...

  1. Analysis of the characteristics of heat transfer enhancement in steam condensers

    International Nuclear Information System (INIS)

    Yan Changqi; Sun Zhongning

    2001-01-01

    The influence of main factors on overall heat transfer was analyzed, and the effects of fouling factors on heat transfer characteristics in steam condenser were clarified. It was proposed that the tube outside enhancement is the most important attribute, when outside heat transfer coefficient increased there will be a big increase in condenser efficiency. The characteristics of heat transfer enhancement by spirally indented tube were investigated. It was proposed that condenser heat transfer efficiency will be raised when the low fin tube or the spirally indented tube with special treated surface were used

  2. Implementing Geothermal Plants in the Copenhagen District Heating System

    DEFF Research Database (Denmark)

    Jensen, Louise Overvad; Hallgreen, Christine Erikstrup; Larsen, Esben

    2003-01-01

    of geothermal energy in Denmark as well as the Danish potential, which, in former investigations, has been found to be around 100.000 PJ annually, and the economical potential is less, about 15 PJ/year. Since a considerable amount of the Danish power supply is tied to weather and the demand for heating......The possibility of implementing geothermal heating in the Copenhagen district-heating system is assessed. This is done by building up general knowledge on the geological factors that influence the development of useable geothermal resources, factors concerning the exploration and utilization......, an increasing demand for flexibility has been raised. Implementing geothermal heating would improve the flexibility in the Eastern Danish power system. Based on this information, as well as, on the hourly values of the expected production and consumption in 2010 and 2020, a model of the Copenhagen power...

  3. Analysis on Operating Parameter Design to Steam Methane Reforming in Heat Application RDE

    Science.gov (United States)

    Dibyo, Sukmanto; Sunaryo, Geni Rina; Bakhri, Syaiful; Zuhair; Irianto, Ign. Djoko

    2018-02-01

    The high temperature reactor has been developed with various power capacities and can produce electricity and heat application. One of heat application is used for hydrogen production. Most hydrogen production occurs by steam reforming that operated at high temperature. This study aims to analyze the feasibility of heat application design of RDE reactor in the steam methane reforming for hydrogen production using the ChemCAD software. The outlet temperature of cogeneration heat exchanger is analyzed to be applied as a feed of steam reformer. Furthermore, the additional heater and calculating amount of fuel usage are described. Results show that at a low mass flow rate of feed, its can produce a temperature up to 480°C. To achieve the temperature of steam methane reforming of 850°C the additional fired heater was required. By the fired heater, an amount of fuel usage is required depending on the Reformer feed temperature produced from the heat exchanger of the cogeneration system.

  4. Flexible use of electricity in heat-only district heating plants

    Directory of Open Access Journals (Sweden)

    Erik Trømborg

    2017-01-01

    Full Text Available European energy systems are in a period of significant transition, with the increasing shares of variable renewable energy (VRE and less flexible fossil-based generation units as predominant factors. The supply-side changes are expected to cause large short-term electricity price volatility. More frequent periods of low electricity prices may mean that electric use in flexible heating systems will become more profitable, and such flexible heating systems may, in turn, improve the integration of increasing shares of VRE. The objective of this study is to analyze the likely future of Nordic electricity price levels and variations and how the expected prices might affect the use of electricity and thermal storage in heat-only district heating plants. We apply the North European energy market model Balmorel to provide scenarios for future hourly electricity prices in years with normal, high, and low inflow levels to the hydro power system. The simulation tool energyPRO is subsequently applied to quantify how these electricity price scenarios affect the hourly use of thermal storage and individual boilers in heat-only district heating plants located in Norway. The two studied example plants use wood chips or heat pump as base load representing common technologies for district heating in Norway. The Balmorel results show that annual differences in inflow is still a decisive factor for Norwegian and Nordic electricity prices in year 2030 and that short-term (daily price variability is expected to increase. In the plant-level simulations, we find that tank storage, which is currently installed in only a few district heating plants in Norway, is a profitable flexibility option that will significantly reduce the use of fossil peak load in both biomass and heat-pump-based systems. Installation of an electric boiler in addition to tank storage is profitable in the heat pump system due to the limited capacity of the heat pump. Electricity will hence, to a

  5. Critical heat flux and transition boiling characteristics for a sodium-heated steam generator tube for LMFBR applications

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, S.; Holmes, D.H.

    1977-04-01

    An experimental program was conducted to characterize critical heat flux (CHF) in a sodium-heated steam generator tube model at a proposed PLBR steam generator design pressure of 7.2 MPa. Water was circulated vertically upward in the tube and the heating sodium was flowing counter-current downward. The experimental ranges were: mass flux, 110 to 1490 kg/s.m/sup 2/ (0.08 to 1.10 10/sup 6/ lbm/h.ft/sup 2/); critical heat flux, 0.16 to 1.86 MW/m/sup 2/ (0.05 to 0.59 10/sup 6/ Btu/h.ft/sup 2/); and critical quality, 0.48 to 1.0. The CHF phenomenon for the experimental conditions is determined to be dryout as opposed to departure from nucleate boiling (DNB). The data are divided into high- and low-mass flux regions.

  6. Proceedings of the third international steam generator and heat exchanger conference

    International Nuclear Information System (INIS)

    1998-01-01

    The Third International Steam Generator and Heat Exchanger conference had the objective to present the state of knowledge of steam generator performance and life management, and also heat exchanger technology. As this conference followed on from the previous conferences held in Toronto in 1990 and 1994, the emphasis was on recent developments, particularly those of the last 4 years. The conference provided an opportunity to operators, designers and researchers in the field of steam generation associated with electricity generation by nuclear energy to present their findings and exchange ideas. The conference endeavoured to do this over the widest possible range of subject areas, including: general operating experience, life management and fitness for service strategies, maintenance and inspection, thermalhydraulics, vibration, fretting and fatigue, materials, chemistry and corrosion and the regulatory issues

  7. Proceedings of the third international steam generator and heat exchanger conference

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-07-01

    The Third International Steam Generator and Heat Exchanger conference had the objective to present the state of knowledge of steam generator performance and life management, and also heat exchanger technology. As this conference followed on from the previous conferences held in Toronto in 1990 and 1994, the emphasis was on recent developments, particularly those of the last 4 years. The conference provided an opportunity to operators, designers and researchers in the field of steam generation associated with electricity generation by nuclear energy to present their findings and exchange ideas. The conference endeavoured to do this over the widest possible range of subject areas,including: general operating experience, life management and fitness for service strategies, maintenance and inspection, thermalhydraulics, vibration, fretting and fatigue, materials, chemistry and corrosion and the regulatory issues.

  8. Effects of steam pretreatment and co-production with ethanol on the energy efficiency and process economics of combined biogas, heat and electricity production from industrial hemp

    Science.gov (United States)

    2013-01-01

    Background The study presented here has used the commercial flow sheeting program Aspen Plus™ to evaluate techno-economic aspects of large-scale hemp-based processes for producing transportation fuels. The co-production of biogas, district heat and power from chopped and steam-pretreated hemp, and the co-production of ethanol, biogas, heat and power from steam-pretreated hemp were analysed. The analyses include assessments of heat demand, energy efficiency and process economics in terms of annual cash flows and minimum biogas and ethanol selling prices (MBSP and MESP). Results Producing biogas, heat and power from chopped hemp has the highest overall energy efficiency, 84% of the theoretical maximum (based on lower heating values), providing that the maximum capacity of district heat is delivered. The combined production of ethanol, biogas, heat and power has the highest energy efficiency (49%) if district heat is not produced. Neither the inclusion of steam pretreatment nor co-production with ethanol has a large impact on the MBSP. Ethanol is more expensive to produce than biogas is, but this is compensated for by its higher market price. None of the scenarios examined are economically viable, since the MBSP (EUR 103–128 per MWh) is higher than the market price of biogas (EUR 67 per MWh). The largest contribution to the cost is the cost of feedstock. Decreasing the retention time in the biogas process for low solids streams by partly replacing continuous stirred tank reactors by high-rate bioreactors decreases the MBSP. Also, recycling part of the liquid from the effluent from anaerobic digestion decreases the MBSP. The production and prices of methane and ethanol influence the process economics more than the production and prices of electricity and district heat. Conclusions To reduce the production cost of ethanol and biogas from biomass, the use of feedstocks that are cheaper than hemp, give higher output of ethanol and biogas, or combined production with

  9. A methodology for the geometric design of heat recovery steam generators applying genetic algorithms

    International Nuclear Information System (INIS)

    Durán, M. Dolores; Valdés, Manuel; Rovira, Antonio; Rincón, E.

    2013-01-01

    This paper shows how the geometric design of heat recovery steam generators (HRSG) can be achieved. The method calculates the product of the overall heat transfer coefficient (U) by the area of the heat exchange surface (A) as a function of certain thermodynamic design parameters of the HRSG. A genetic algorithm is then applied to determine the best set of geometric parameters which comply with the desired UA product and, at the same time, result in a small heat exchange area and low pressure losses in the HRSG. In order to test this method, the design was applied to the HRSG of an existing plant and the results obtained were compared with the real exchange area of the steam generator. The findings show that the methodology is sound and offers reliable results even for complex HRSG designs. -- Highlights: ► The paper shows a methodology for the geometric design of heat recovery steam generators. ► Calculates product of the overall heat transfer coefficient by heat exchange area as a function of certain HRSG thermodynamic design parameters. ► It is a complement for the thermoeconomic optimization method. ► Genetic algorithms are used for solving the optimization problem

  10. Planning study 'District Heating' Oberhausen/Western Ruhr district. Short version. Planstudie Fernwaermeversorgung Oberhausen/westliches Ruhrgebiet. Kurzfassung

    Energy Technology Data Exchange (ETDEWEB)

    1978-01-01

    After a brief description of how the heat demand was assessed, the heat demand now and up to 1990 is assessed as well as the possibility to meet it. The possibilities of heat decoupling from thermal power plants are outlined as well as the future heat transport and the future heat distribution in the planning area. Proposals are made for development stages of the district heating grid, and results of rentability calculations are presented.

  11. Master plan study - District heating Sillamaee municipality. Estonia. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    The main deficiencies of the district heating system in Sillamae (Estonia) were identified as being inefficiency of the heat and power production plant, which has a very low capacity, lack of means for consumers to control their energy consumption due to the existing constant flow system, pollution from heat and power production based on oil shale, water and heat losses from the network and unclear agreements between the Silmet factory and Sillamae municipality. The available capital for funding is limited. It was investigated where in the system investments would have the greatest effect. A scenario where heat is supplied from individual gas-fired boilers was calculated. A financially viable scenario would be to change from cogeneration of heat and power (CHP) based on oil shale to either individual natural gas supply or peat-fueled heat production. The Sillamae municipality and the Estonian government should agree on a solution for Sillamae. There will be a cash flow problem if the project is implemented. This can be partly solved by introducing a longer loan period. it is expected that there will be no substantial changes in the consumers` heat demand in the `do nothing`scenario, and in other scenarios ca. 520 Tj/p.a. from the Solmet factory, 530 Tj/p.a. from the town and 260 Tj/p.a. as heat losses, totaling 1310 Tj/p.a.. In another scenario - the introduction of natural gas - the town`s heat demand will be 530 Tj/p.a. and there will be no heat losses. More detailed studies of environmental impacts should be undertaken. (ARW)

  12. District Heating Demonstration project. Bydgoszcz, Poland, Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-06-01

    The project was finished in January 1999. The present final report outlines the activities of the pilot project. The activities of the project were: Development of a general model or a design strategy for the modernisation of group substations; Training of selected staff in updated design and latest technologies; Comparing experiences from the reconstructed heat exchanger station with alternative solutions; Investigation of potential sources of financing for the modernisation of the district heating system based on a revised feasibility study. The development of a general model for the future design of the heat exchanger station and the substations resulted in a design guideline which was used for the design of the heat exchanger station. KPEC selected the heat exchanger station CC02, located in area B1, as the object for the heat exchanger reconstruction. The station supplies 42 substations in 20 dwelling houses with a total heat demand of 11 MW. The design of the reconstruction began in the autumn of 1996. The equipment was procured during the spring of 1997 and the bulk of the installation work was finished by October 1997. The appointed design engineer participated in two study tours to Denmark. During the implementation the project was enlarged with an addendum. The addendum consisted of a modernisation of twelve building substations. The monitoring programme was enlarged accordingly and the efficiency of the two solutions were compared and evaluated through the monitoring programme. Even though some of the data are rather limited, the monitoring programme reveals a tendency towards the substation modernisation being twice as efficient as the heat exchanger modernisation. The reconstruction of the heat exchanger station has indicated a heat saving potential of 10% whereas the substation project has indicated a heat saving potential of 20%. The project further shows a huge potential for power savings in the main pumps due to the automatic control. (EHS)

  13. Master plan study - District heating Sillamaee municipality. Estonia. Final report

    International Nuclear Information System (INIS)

    1997-03-01

    The main deficiencies of the district heating system in Sillamae (Estonia) were identified as being inefficiency of the heat and power production plant, which has a very low capacity, lack of means for consumers to control their energy consumption due to the existing constant flow system, pollution from heat and power production based on oil shale, water and heat losses from the network and unclear agreements between the Silmet factory and Sillamae municipality. The available capital for funding is limited. It was investigated where in the system investments would have the greatest effect. A scenario where heat is supplied from individual gas-fired boilers was calculated. A financially viable scenario would be to change from cogeneration of heat and power (CHP) based on oil shale to either individual natural gas supply or peat-fueled heat production. The Sillamae municipality and the Estonian government should agree on a solution for Sillamae. There will be a cash flow problem if the project is implemented. This can be partly solved by introducing a longer loan period. it is expected that there will be no substantial changes in the consumers' heat demand in the 'do nothing'scenario, and in other scenarios ca. 520 Tj/p.a. from the Solmet factory, 530 Tj/p.a. from the town and 260 Tj/p.a. as heat losses, totaling 1310 Tj/p.a.. In another scenario - the introduction of natural gas - the town's heat demand will be 530 Tj/p.a. and there will be no heat losses. More detailed studies of environmental impacts should be undertaken

  14. Possibility of using adsorption refrigeration unit in district heating network

    Science.gov (United States)

    Grzebielec, Andrzej; Rusowicz, Artur; Jaworski, Maciej; Laskowski, Rafał

    2015-09-01

    Adsorption refrigeration systems are able to work with heat sources of temperature starting with 50 °C. The aim of the article is to determine whether in terms of technical and economic issues adsorption refrigeration equipment can work as elements that produce cold using hot water from the district heating network. For this purpose, examined was the work of the adsorption air conditioning equipment cooperating with drycooler, and the opportunities offered by the district heating network in Warsaw during the summer. It turns out that the efficiency of the adsorption device from the economic perspective is not sufficient for production of cold even during the transitional period. The main problem is not the low temperature of the water supply, but the large difference between the coefficients of performance, COPs, of adsorption device and a traditional compressor air conditioning unit. When outside air temperature is 25 °C, the COP of the compressor type reaches a value of 4.49, whereas that of the adsorption device in the same conditions is 0.14. The ratio of the COPs is 32. At the same time ratio between the price of 1 kWh of electric power and 1 kWh of heat is only 2.85. Adsorption refrigeration equipment to be able to compete with compressor devices, should feature COPads efficiency to be greater than 1.52. At such a low driving temperature and even changing the drycooler into the evaporative cooler it is not currently possible to achieve.

  15. Experimental investigations on waterside corrosion problems of sodium-heated steam generators

    International Nuclear Information System (INIS)

    Buescher, E.; Haubold, W.; Jansing, W.; Vinzens, K.

    1975-01-01

    Based on experimental results, it is shown that the formation of a protective magnetite layer in sodium-heated steam generators - operated with neutral demineralized water - proceeds very fast. The stability of the magnetite layer is excellent even at sudden load changes and at the start-up or shut-down operation. (author)

  16. Certification of materials for steam generator condensor and regeneration heat exchanger for nuclear plant

    International Nuclear Information System (INIS)

    Stevanovicj, M.V.; Jovashevicj, V.J.; Jovashevicj, V.D.J.; Spasicj, Zh.Lj.

    1977-01-01

    In the construction of a nuclear power plant almost all known materials are used. The choice depends on working conditions. In this work standard specifications of contemporary materials that take part in larger quantities in the following components of the secondary circuit of PWR-type nuclear power plant are proposed: steam generator with moisture separator, condensor and regenerative heat eXchanger

  17. Experimental investigations on waterside corrosion problems of sodium-heated steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Buescher, E; Haubold, W; Jansing, W; Vinzens, K

    1975-07-01

    Based on experimental results, it is shown that the formation of a protective magnetite layer in sodium-heated steam generators - operated with neutral demineralized water - proceeds very fast. The stability of the magnetite layer is excellent even at sudden load changes and at the start-up or shut-down operation. (author)

  18. Modelling and verification of once-through subcritical heat recovery steam generator

    International Nuclear Information System (INIS)

    Lee, Chae Soo; Choi, Young Jun; Kim, Hyun Gee; Yang, Ok Chul; Chong Chae Hon

    2004-01-01

    The once-through heat recovery steam generator is ideally matched to very high temperature and pressure, well into the supercritical range. Moreover this type of boiler is structurally simpler than drum type boiler. In drum type boiler, each tube play a well-defined role: water preheating, vaporization, superheating. Empirical equations are available to predict the average heat transfer coefficient for each regime. For once-through heat recovery steam generator, this is no more the case and mathematical models have to be adapted to account for the disappearance of drum type economizer, boiler, superheater. General equations have to be used for each tube of boiler, and actual heat transfer condition in each tube has to be identified

  19. Heat planning for fossil-fuel-free district heating areas with extensive end-use heat savings

    DEFF Research Database (Denmark)

    Harrestrup, Maria; Svendsen, S.

    2014-01-01

    is a theoretical investigation of the district heating system in the Copenhagen area, in which heat conservation is related to the heat supply in buildings from an economic perspective. Supplying the existing building stock from low-temperature energy resources, e.g. geothermal heat, might lead to oversized......The Danish government plans to make the Danish energy system to be completely free of fossil fuels by 2050 and that by 2035 the energy supply for buildings and electricity should be entirely based on renewable energy sources. To become independent from fossil fuels, it is necessary to reduce...... the energy consumption of the existing building stock, increase energy efficiency, and convert the present heat supply from fossil fuels to renewable energy sources. District heating is a sustainable way of providing space heating and domestic hot water to buildings in densely populated areas. This paper...

  20. Electricity eliminates rust from district heat pipes. The new deoxidation method works on radiators

    Energy Technology Data Exchange (ETDEWEB)

    Sonninen, R.; Leisio, C.

    1996-11-01

    Oxygen dissolving in district heating water through district heat pipes and pipe joints made of plastic corrodes many small and medium-size district heating systems, resulting in heat cuts in the buildings connected to these systems. IN some cases, corrosion products have even circulated back to district heating power plants, thus hampering heat generation in the worst of cases. People residing in blocks of flats where some radiator components are made of plastic also face a similar problem, though on a smaller scale. A small and efficient electrochemical deoxidation cell has now been invented to eliminate this nuisance, which occurs particularly in cold winter weather. (orig.)

  1. Low-temperature nuclear heat applications: Nuclear power plants for district heating

    International Nuclear Information System (INIS)

    1987-08-01

    The IAEA reflected the needs of its Member States for the exchange of information in the field of nuclear heat application already in the late 1970s. In the early 1980s, some Member States showed their interest in the use of heat from electricity producing nuclear power plants and in the development of nuclear heating plants. Accordingly, a technical committee meeting with a workshop was organized in 1983 to review the status of nuclear heat application which confirmed both the progress made in this field and the renewed interest of Member States in an active exchange of information about this subject. In 1985 an Advisory Group summarized the Potential of Low-Temperature Nuclear Heat Application; the relevant Technical Document reviewing the situation in the IAEA's Member States was issued in 1986 (IAEA-TECDOC-397). Programme plans were made for 1986-88 and the IAEA was asked to promote the exchange of information, with specific emphasis on the design criteria, operating experience, safety requirements and specifications for heat-only reactors, co-generation plants and power plants adapted for heat application. Because of a growing interest of the IAEA's Member States about nuclear heat employment in the district heating domaine, an Advisory Group meeting was organized by the IAEA on ''Low-Temperature Nuclear Heat Application: Nuclear Power Plants for District Heating'' in Prague, Czechoslovakia in June 1986. The information gained up to 1986 and discussed during this meeting is embodied in the present Technical Document. 22 figs, 11 tabs

  2. On the heat exchange tube failures in steam generators at NPPs with WWER reactors

    International Nuclear Information System (INIS)

    Titov, V.F.; Banyuk, G.F.; Brykov, S.I.

    1992-01-01

    Data on dynamics of failed heat exchanging tube closing in steam generators of NPPs with WWER type reactors for the whole period of their operation are presented. It is shown that the main cause of the tube failures consists in their corrosion cracking under stresses. The effect of chlorine ions on tubes is intensified by the presence of porous sediments on heat exchaning surfaces in quantities exceeding 150 g/m 2

  3. Containment for low temperature district nuclear-heating reactor

    International Nuclear Information System (INIS)

    He Shuyan; Dong Duo

    1992-03-01

    Integral arrangement is adopted for Low Temperature District Nuclear-heating Reactor. Primary heat exchangers, control rod drives and spent fuel elements are put in the reactor pressure vessel together with reactor core. Primary coolant flows through reactor core and primary heat exchangers in natural circulation. Primary coolant pipes penetrating the wall of reactor pressure vessel are all of small diameters. The reactor vessel constitutes the main part of pressure boundary of primary coolant. Therefore the small sized metallic containment closed to the wall of reactor vessel can be used for the reactor. Design principles and functions of the containment are as same as the containment for PWR. But the adoption of small sized containment brings about some benefits such as short period of manufacturing, relatively low cost, and easy for sealing. Loss of primary coolant accident would not be happened during the rupture accident of primary coolant pressure boundary inside the containment owing to its intrinsic safety

  4. Heat pumps as a way to Low or Zero Emission district heating systems

    Directory of Open Access Journals (Sweden)

    Jadwiszczak Piotr

    2017-01-01

    In traditional district heating (DH system heat is generated from fossil fuel (FF combustion in heating only boilers (HOB or in combined heat and power (CHP plants. It results in greenhouse gases and other pollutants emission. The reduction of emission is one of the main target in EU climate policy. Among the alternative technologies in DH heat pumps (HP play a crucial role and enable to decrease or even eliminate emission to create a low or zero emission (LZE DH system. The emission reduction effect of integration the large scale HP units into DH systems can by defined by four groups of factors: the share of HP in the heat demand, the heat source for HP, the driving energy for HP and heat sink for HP. This paper illustrates the main options for large scale HP units application for LZE DH based on HP technology.

  5. Direct Hysteresis Heating of Catalytically Active Ni–Co Nanoparticles as Steam Reforming Catalyst

    DEFF Research Database (Denmark)

    Mortensen, Peter Mølgaard; Engbæk, Jakob Soland; Vendelbo, Søren Bastholm

    2017-01-01

    We demonstrated a proof-of-concept catalytic steam reforming flow reactor system heated only by supported magnetic nickel–cobalt nanoparticles in an oscillating magnetic field. The heat transfer was facilitated by the hysteresis heating in the nickel–cobalt nanoparticles alone. This produced...... a sufficient power input to equilibrate the reaction at above 780 °C with more than 98% conversion of methane. The high conversion of methane indicated that Co-rich nanoparticles with a high Curie temperature provide sufficient heat to enable the endothermic reaction, with the catalytic activity facilitated...... by the Ni content in the nanoparticles. The magnetic hysteresis losses obtained from temperature-dependent hysteresis measurements were found to correlate well with the heat generation in the system. The direct heating of the catalytic system provides a fast heat transfer and thereby overcomes the heat...

  6. Effects of heat and electricity saving measures in district-heated multistory residential buildings

    International Nuclear Information System (INIS)

    Truong, Nguyen Le; Dodoo, Ambrose; Gustavsson, Leif

    2014-01-01

    Highlights: • We analyzed the potential for energy savings in district heated buildings. • Measures that reduce more peak load production give higher primary energy savings. • Efficient appliances increase heat demand but give net primary energy savings. • Efficient appliances give the largest net primary energy savings. - Abstract: The effects of heat and electricity saving measures in district-heated buildings can be complex because these depend not only on how energy is used on the demand side but also on how energy is provided from the supply side. In this study, we analyze the effects of heat and electricity saving measures in multistory concrete-framed and wood-framed versions of an existing district-heated building and examine the impacts of the reduced energy demand on different district heat (DH) production configurations. The energy saving measures considered are for domestic hot water reduction, building thermal envelope improvement, ventilation heat recovery (VHR), and household electricity savings. Our analysis is based on a measured heat load profile of an existing DH production system in Växjö, Sweden. Based on the measured heat load profile, we model three minimum-cost DH production system using plausible environmental and socio-political scenarios. Then, we investigate the primary energy implications of the energy saving measures applied to the two versions of the existing building, taking into account the changed DH demand, changed cogenerated electricity, and changed electricity use due to heat and electricity saving measures. Our results show that the difference between the final and primary energy savings of the concrete-framed and wood-framed versions of the case-study building is minor. The primary energy efficiency of the energy saving measures depends on the type of measure and on the composition of the DH production system. Of the various energy saving measures explored, electricity savings give the highest primary energy savings

  7. The analysis of thermal network of district heating system from investor point of view

    Science.gov (United States)

    Takács, Ján; Rácz, Lukáš

    2016-06-01

    The hydraulics of a thermal network of a district heating system is a very important issue, to which not enough attention is often paid. In this paper the authors want to point out some of the important aspects of the design and operation of thermal networks in district heating systems. The design boundary conditions of a heat distribution network and the requirements on active pressure - circulation pump - influencing the operation costs of the centralized district heating system as a whole, are analyzed in detail. The heat generators and the heat exchange stations are designed according to the design heat loads after thermal insulation, and modern boiler units are installed in the heating plant.

  8. Technoeconomic analysis of a biomass based district heating system

    International Nuclear Information System (INIS)

    Zhang, H.; Ugursal, V.I.; Fung, A.

    2005-01-01

    This paper discussed a proposed biomass-based district heating system to be built for the Pictou Landing First Nation Community in Nova Scotia. The community centre consists of 6 buildings and a connecting arcade. The methodology used to size and design heating, ventilating and air conditioning (HVAC) systems, as well as biomass district energy systems (DES) were discussed. Annual energy requirements and biomass fuel consumption predictions were presented, along with cost estimates. A comparative assessment of the system with that of a conventional oil fired system was also conducted. It was suggested that the design and analysis methodology could be used for any similar application. The buildings were modelled and simulated using the Hourly Analysis Program (HAP), a detailed 2-in-1 software program which can be used both for HVAC system sizing and building energy consumption estimation. A techno-economics analysis was conducted to justify the viability of the biomass combustion system. Heating load calculations were performed assuming that the thermostat was set constantly at 22 degrees C. Community centre space heating loads due to individual envelope components for 3 different scenarios were summarized, as the design architecture for the buildings was not yet finalized. It was suggested that efforts should be made to ensure air-tightness and insulation levels of the interior arcade glass wall. A hydronic distribution system with baseboard space heating units was selected, comprising of a woodchip boiler, hot water distribution system, convective heating units and control systems. The community has its own logging operation which will provide the wood fuel required by the proposed system. An outline of the annual allowable harvest covered by the Pictou Landing Forestry Management Plan was presented, with details of proposed wood-chippers for the creation of biomass. It was concluded that the woodchip combustion system is economically preferable to the

  9. Can high temperature steam electrolysis function with geothermal heat?

    International Nuclear Information System (INIS)

    Sigurvinsson, J.; Mansilla, C.; Werkoff, F.; Lovera, P.

    2007-01-01

    It is possible to improve the performance of electrolysis processes by operating at a high temperature. This leads to a reduction in electricity consumption but requires a part of the energy necessary for the dissociation of water to be in the form of thermal energy. Iceland produces low cost electricity and very low cost geothermal heat. However, the temperature of geothermal heat is considerably lower than the temperature required at the electrolyser's inlet, making heat exchangers necessary to recuperate part of the heat contained in the gases at the electrolyser's outlet. A techno-economic optimisation model devoted to a high-temperature electrolysis (HTE) process which includes electrolysers as well as a high temperature heat exchanger network was created. Concerning the heat exchangers, the unit costs used in the model are based on industrial data. For the electrolyser cells, the unit cost scaling law and the physical sub-model we used were formulated using analogies with solid oxide fuel cells. The method was implemented in a software tool, which performs the optimisation using genetic algorithms. The first application of the method is done by taking into account the prices of electricity and geothermal heat in the Icelandic context. It appears that even with a geothermal temperature as low as 230 degrees C, the HTE could compete with alkaline electrolysis. (authors)

  10. Geothermal District Heating System City of Klamath Falls

    Energy Technology Data Exchange (ETDEWEB)

    Lienau, Paul J; Rafferty, Kevin

    1991-12-01

    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. The shallow geothermal reservoir in Klamath falls extends for at least 6.8 miles in a northwest-southeast direction, as shown on Figure 1, with a width of about 2 miles. More than 550 thermal wells ranging in depth from about 10 to 2,000 ft, and obtaining or contacting water from 70 to 230oF, have been drilled into the reservoir. The system is not geologically homogeneous. Great variations in horizontal permeability and many vertical discontinuities exist because of stratigraphy and structure of the area. Basalt flows, eruptive centers, fluvial and lacustrine deposits, diatomite and pyroclastic materials alternate in the rock column. Normal faults with large throw (estimated up to 1,700 ft) are spaced less than 3,300 ft apart and appear to be the main avenue of vertical movement of hot fluids. In order to more effectively utilize this resource, the city of Klamath Falls decided in 1978 to apply for a federal grant (Program Opportunity Notice to cost share field experiment projects) to construct a geothermal district heating system that would deliver geothermal fluids to areas not located on the resource. In 1977, several Geo-Heat Center staff members visited Reykjavik, Iceland, to study the design of their geothermal district heating systems. This was in part the basis for the conceptual design and feasibility study (Lund, 1979) of a downtown commercial district. The main difference

  11. Field Test of a Steam Condenser Heat Sink Concept

    Science.gov (United States)

    1974-01-01

    stored underground for a specified time. A functional and economical heat rejection system is an important design consideration for such...per- mits the use of tunnels for other than just heat sink purposes. If existing tunnels can be used, the concept becomes economically attractive...that the water meter readings aie a valid indication of the mpu ! and that condensate was lost bv seepage thionuli the lock and or ballast into the

  12. Investigations on a new internally-heated tubular packed-bed methanol–steam reformer

    KAUST Repository

    Nehe, Prashant

    2015-05-01

    Small-scale reformers for hydrogen production through steam reforming of methanol can provide an alternative solution to the demand of continuous supply of hydrogen gas for the operation of Proton Exchange Membrane Fuel Cells (PEMFCs). A packed-bed type reformer is one of the potential designs for such purpose. An externally heated reformer has issues of adverse lower temperature in the core of the reformer and significant heat loss to the environment thus impacting its performance. Experimental and numerical studies on a new concept of internally heated tubular packed-bed methanol-steam reformer have been reported in this paper with improved performance in terms of higher methanol conversion and reduced heat losses to surroundings. CuO/ZnO/Al2O3 is used as the catalyst for the methanol-steam reforming reaction and a rod-type electric heater at the center of the reactor is used for supplying necessary heat for endothermic steam reforming reaction. The vaporizer and the reformer unit with a constant volume catalyst bed are integrated in the annular section of a tubular reformer unit. The performance of the reformer was investigated at various operating conditions like feed rate of water-methanol mixture, mass of the catalyst and reforming temperature. The experimental and numerical results show that the methanol conversion and CO concentration increase with internal heating for a wide range of operating conditions. The developed reformer unit generates 50-80W (based on lower heating value) of hydrogen gas for applications in PEMFCs. For optimized design and operating conditions, the reformer unit produced 298sccm reformed gas containing 70% H2, 27% CO2 and 3% CO at 200-240°C which can produce a power output of 25-32W assuming 60% fuel cell efficiency and 80% of hydrogen utilization in a PEMFC. © 2015 Hydrogen Energy Publications, LLC.

  13. Heat release from B4C oxidation in steam and air

    International Nuclear Information System (INIS)

    Belovsky, L.

    1996-01-01

    BWR and some PWR cores contain boron carbide (B 4 C) as neutron absorber. During a severe accident, the B 4 C can potentially react with steam under release of heat and hydrogen. Although models for B 4 C oxidation already exist in MELCOR and SCDAP/RELAP5, a development of a new model for another computer code seems to be difficult due to a missing comprehensive description of the current modelling methodology and scarce experimental data. The aim of this paper is to highlight the key points of the B 4 C oxidation using the existing available experimental data and to perform a simple heat balance analysis of the B 4 C/steam and B 4 C/air chemical reactions. The analysis of literature data shows that the B 4 C oxidation phenomenon is qualitatively well described below 1000 deg. C. However, no reliable data exist for the reaction kinetics especially above this temperature. It was found that the experimental results strongly depend on the experimental arrangement. The reaction heats, calculated in this study, indicate that the B 4 C oxidation is an exothermic reaction, releasing more heat in air than in steam. The formation of boric acids from the boron oxide increases the heat release from B 4 C by ∼ 10%, in the worst case. Although the total heat, released in a PWR core from the B 4 C oxidation, is probably much smaller than the heat released from the Zr/steam reaction, it is not excluded that the B 4 C oxidation can locally contribute to the damage of the control elements due to local overheating. Modelling of these phenomena is, however, very difficult due to the complex geometry of the liquefied control elements and due to absence of suitable data on the reaction kinetics. (author). 25 refs, 2 figs, 3 tabs

  14. Implications of small water leak reactions on sodium heated steam generator design

    Energy Technology Data Exchange (ETDEWEB)

    Smedley, J A

    1975-07-01

    Various types of sodium water reactions have been looked on as possibly causing hazard conditions in sodium heated steam generator units ranging from the very improbable boiler tube double ended guillotine fracture to the almost certain occurrence of micro-leaks. Within this range small water leaks reactions have attracted particular interest and the present paper looks at the principles of associating the reactions with detection and protection systems for Commercial Fast Reactors. A method is developed for assessing whether adequate protection has been provided against the effects of small water leak reactions in a steam generator unit. (author)

  15. Radiation heat transfer within and from high temperature plumes composed of steam and molten nuclear debris

    International Nuclear Information System (INIS)

    Condiff, D.W.

    1987-03-01

    The Differential Approximation of Radiation Heat Transfer which includes anisotropic scattering is formulated to account for multiple source and temperature fields of multiphase flow. The formulation is applied to a simplified model of a plume consisting of high temperature emissive particles in steam at parametrically variable lower temperatures. Parametric model calculations are presented which account for spectral emission and absorption by steam using a band approximation as well as emission, absorption and scattering by the debris. The results are found to be far more sensitive to emission properties of individual particles, than to their scattering properties at high temperatures

  16. Korean district heating. Part 2: Investigation of the consumption pattern in a substation at Korea District Heating Corporation at the turn of the year 1994/95

    Energy Technology Data Exchange (ETDEWEB)

    Joensson, Mats; Olsson, Nils

    1996-05-01

    This thesis, which is the second part of two, analyses the consumption pattern and the conditions for district heating in the Republic of Korea at the turn of the year 1994-95. It is based on a study made in Seoul at Korea District Heating Corporation which is the largest district heating utility in Korea. District heating was introduced in the 80s because of the environmental advantages. In 1994 KDHC provided 340 000 households with district heating. KDHC receives most of its thermal energy from combined heat and power plants which use natural gas as fuel. One substation was chosen for the investigation and temperature, flow, and pressure were measured. A typical Korean substation has heat exchangers connected in parallel in only one step and the apartment complexes use floor heating for internal heating. The space heating load shows a linear relation to the outdoor temperature. The hot tap-water consumption shows a highly varying pattern with peak loads in the morning and evening. There were also an oscillating pattern for some of the temperatures and flows caused by poor regulation. DH suits very well to Korea with its climate and the overpopulated cities. KDHC:s expansion will help to make Korea one of the leading countries in modern district heating. 10 refs, 36 figs, 11 tabs

  17. LeBreton Flats district heating: Institutional issues

    Energy Technology Data Exchange (ETDEWEB)

    Gerow, L.B.; Bernstein, H.

    1981-12-01

    Despite the growing popularity in Europe of district heating as an alternative to conventional systems, a number of institutional barriers blocked the road to its successful implementation in Canada. These hurdles include questions of ownership, operation/administration, consumer accountability, financial arrangements, and general consumer acceptance of a new technology. In deciding on ownership, the major issues were legal. Provincial laws to be complied with included The Municipal Franchises Act, The Public Utilities Act, The Municipal Act and The Ontario Municipal Board Act. The operation and administration of the project were also beset with legal complications. The relevant laws were The Boilers and Pressure Vessels Act, and The Environmental Assessment Act. How to charge individual users (consumer accountability) raised a number of technical problems including metering and rate-setting for hot water distribution, and heat borrowing between units. The report recommends that groups planning to implement district heating are advised to allow plenty of lead time for obtaining approvals and franchising arrangements so as not to jeopardize construction schedules. 3 refs.

  18. High temperature technological heat exchangers and steam generators with helical coil assembly tube bundle

    International Nuclear Information System (INIS)

    Korotaev, O.J.; Mizonov, N.V.; Nikolaevsky, V.B.; Nazarov, E.K.

    1990-01-01

    Analysis of thermal hydraulics characteristics of nuclear steam generators with different tube bundle arrangements and waste heat boilers for ammonia production units was performed on the basis of operating experience results and research and development data. The present report involves the obtained information. The estimations of steam generator performances and repair-ability are given. The significant temperature profile of the primary and secondary coolant flows are attributed to all steam generator designs. The intermediate mixing is found to be an effective means of temperature profile overcoming. At present the only means to provide an effective mixing in heat exchangers of the following types: straight tubes, field tubes, platen tubes and multibank helical coil tubes (with complicated bend distribution along their length) are section arrangements in series in conjunction with forced and natural mixing in connecting lines. Development of the unificated system from mini helical coil assemblies allows to design and manufacture heat exchangers and steam generators within the wide range of operating conditions without additional expenses on the research and development work

  19. Comparing the steam and electric heat tracing solutions for petrochemical or refining facilities

    Energy Technology Data Exchange (ETDEWEB)

    Young, Joseph G.; McQueen, Greg [Tyco Thermal Controls, Belgie (Belgium)

    2012-07-01

    In this era of energy conservation and cost reduction, the ability to effectively select the optimal solution to meet the heat management system needs of petrochemical or refining facilities is becoming increasingly important. Depending on the type and location of the plant, a heat management system (HMS) can comprise a significant portion of the overall capital expenditure, as well as the ongoing operating and maintenance costs. Several important heat management system design decisions affect the financial operations of a facility, including the selection of the heat tracing technology, the utility distribution scheme, and the insulation system criteria, among others. However, most of these decisions are made early in the project life-cycle without thorough analysis of the various options available. From a high level perspective, numerous heat trace media should be considered, including electric, steam, tempered water, and glycol. These systems also have different impacts on piping systems within the plant battery limits (ISBL) and transfer lines outside of the battery limits (OSBL). This paper takes a careful look at two of the predominant heat tracing technologies - electric heat tracing and steam tracing - and compares these within the larger framework of the heat management system, and relative to petrochemical or refining facilities within the general Brazil geography. In the broader context, a heat management system is defined as the heat tracing technology itself, the utility distribution associated with that technology, the control and monitoring scheme associated with that technology, and the insulation system. We will evaluate the capital expenditure cost, operating expenditure cost, and overall reliability of the electric and steam tracing mediums in both the ISBL and OSBL environments within this broader context. (author)

  20. Exergoenvironmental analysis for a geothermal district heating system: An application

    International Nuclear Information System (INIS)

    Keçebaş, Ali

    2016-01-01

    Energy sources are of great importance in relation to pollution of the world. The use of renewable energy resources and the creation of more efficient energy systems make great contributions to the prevention of greenhouse gases. Recently, many studies indicate that the energy conversion systems have many advantages in terms of technical and economic point of view. In near future, environmental impact is going to play an important role in the selection/design of such energy resources and systems. In this study, the Afyon GDHS (geothermal district heating system) having actual operating conditions is investigated at the component level in terms of environmental impact by using exergoenvironmental analysis. Moreover, the effects of ambient and wellhead temperatures on the environmental impacts of the system are discussed. The results show that a great part of total environmental impact of the system occurs from the exergy destructions of the components. Therefore, the environmental impacts can be reduced by improving their exergetic efficiencies instead of design changes of the system components. The environmental impacts of the system are reduced when the ambient temperature decreases and the wellhead temperature increases. Thus, it might not be necessary to conduct separately the exergoenvironmental analysis for different ambient temperatures. - Highlights: • Using exergoenvironmental analysis in a geothermal district heating for the first time. • Evaluating environmental impact of a geothermal district heating system. • Discussing the effects of ambient and wellhead temperatures on the environmental impact. • Total environmental impact of the system occurs from exergy destructions of components. • The exergoenvironmental analysis can be done only once for all the ambient temperatures.

  1. An evaluation of analytical heat transfer area with various boiling heat transfer correlations in steam generator thermal sizing

    International Nuclear Information System (INIS)

    Jung, B. R.; Park, H. S.; Chung, D. M.; Baik, S. J.

    1999-01-01

    The computer program SAFE has been used to size and analyze the performance of a steam generator which has two types of heat transfer regions in Korean Standard Nuclear Power Plants (KSNP) and Korean Next Generation Reactor (KNGR) design. The SAFE code calculates the analytical boiling heat transfer area using the modified form of the saturated nucleate pool boiling correlation suggested by Rohsenow. The predicted heat transfer area in the boiling region is multiplied by a constant to obtain a final analytical heat transfer area. The inclusion of the multiplier in the analytical calculation has some disadvantage of loss of complete correlation by the governing heat transfer equation. Several comparative analyses have been performed quantitatively to evaluate the possibility of removing the multiplier in the analytical calculation in the SAFE code. The evaluation shows that the boiling correlation and multiplier used in predicting the boiling region heat transfer area can be replaced with other correlations predicting nearly the same heat transfer area. The removal of multiplier included in the analytical calculation will facilitate a direct use of a set of concerned analytical sizing values that can be exactly correlated by the governing heat transfer equation. In addition this will provide more reasonable basis for the steam generator thermal sizing calculation and enhance the code usability without loss of any validity of the current sizing procedure. (author)

  2. A modeling approach for district heating systems with focus on transient heat transfer in pipe networks

    DEFF Research Database (Denmark)

    Mohammadi, Soma; Bojesen, Carsten

    2015-01-01

    the temperature in DH systems. The main focus is on modeling transient heat transfer in pipe networks regarding the time delays between the heat supply unit and the consumers, the heat loss in the pipe networks and the consumers’ dynamic heat loads. A pseudo-dynamic approach is adopted and also the implicit...... district heating networks [DHN] characteristics. This paper is presenting a new developed model, which reflects the thermo-dynamic behavior of DHN. It is designed for tree network topologies. The purpose of the model is to serve as a basis for applying a variety of scenarios towards lowering...... finite element method is applied to simulate transient temperature changes in pipe networks. The model is calculating time series data related to supply temperature to the DHN from heat production units, heat loads and return temperature related to each consumer to calculate dynamic temperature changes...

  3. Tests of an experimental steam generator heated by sodium-potassium flow

    International Nuclear Information System (INIS)

    Robin, M.G.; Duchatelle, L.; Nucheze, L. de

    1974-01-01

    The first boiler heated by liquid alkaline metal flow, installed at the C.E.A. Heat Test Centre at Grand-Quevilly, near Rouen, was a double-walled 5MW model fed with water at 220 deg C and producing superheated steam at 545 deg C and at an effective pressure of 125 bar. From 1965 to 1967, in the course of more than 8,000 hours of operation under varied conditions (specific water flow rates between 110 and 1,200kg/sq.m./sec., steam pressures of 85 and 125 bar), some 200 results of stationary operating conditions were obtained. These were compared with calculated predictions. After specifying the laws of exchange utilized, the authors discuss the heat transfer results and pressure loss values [fr

  4. Including district heating pipelines in absolute liability laws

    Energy Technology Data Exchange (ETDEWEB)

    Gronau, W

    1977-10-01

    On January 1, 1978 the provisions of the Act Amending the Rules of Liability Damages have entered into force. Formally this means that the provisions of the Reich Liability Act (Reichshaftpflichtgesetz, RHG) and those of the Act on Liability with Respect to Property Damage of Railways and Tramways (SHG) are now combined under the new term of Liability Act (Haftpflichtgesetz). In material terms it means that the district heat industry with its supply pipelines is subject to absolute liability. This creates a liability situation for this industry which has been existing for the electricity and gas industries since 1943 as a result of an amendment of the Reich Liability Act.

  5. Endotoxin inactivation via steam-heat treatment in dilute simethicone emulsions used in biopharmaceutical processes.

    Science.gov (United States)

    Britt, Keith A; Galvin, Jeffrey; Gammell, Patrick; Nti-Gyabaah, Joseph; Boras, George; Kolwyck, David; Ramirez, José G; Presente, Esther; Naugle, Gregory

    2014-01-01

    Simethicone emulsion is used to regulate foaming in cell culture operations in biopharmaceutical processes. It is also a potential source of endotoxin contamination. The inactivation of endotoxins in dilute simethicone emulsions was assessed as a function of time at different steam temperatures using a Limulus amebocyte lysate kinetic chromogenic technique. Endotoxin inactivation from steam-heat treatment was fit to a four-parameter double exponential decay model, which indicated that endotoxin inactivation was biphasic, consisting of fast and slow regimes. In the fast regime, temperature-related effects were dominant. Transitioning into the slow regime, the observed temperature dependence diminished, and concentration-related effects became increasingly significant. The change in the Gibbs free energy moving through the transition state indicated that a large energy barrier must be overcome for endotoxin inactivation to occur. The corresponding Arrhenius pre-exponential factor was >10(12) s(-1) suggesting that endotoxins in aqueous solution exist as aggregates. The disorder associated with the endotoxin inactivation reaction pathway was assessed via the change in entropy moving through the transition state. This quantity was positive indicating that endotoxin inactivation may result from hydrolysis of individual endotoxin molecules, which perturbs the conformation of endotoxin aggregates, thereby modulating the biological activity observed. Steam-heat treatment decreased endotoxin levels by 1-2 logarithm (log) reduction (LRV), which may be practically relevant depending on incoming raw material endotoxin levels. Antifoam efficiency and cell culture performance were negligibly impacted following steam-heat treatment. The results from this study show that steam-heat treatment is a viable endotoxin control strategy that can be implemented to support large-scale biopharmaceutical manufacturing. © 2014 American Institute of Chemical Engineers.

  6. Forced convection heat transfer of steam in a square ribbed channel

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jiazeng; Gao, Jianmin; Gao, Tieyu [Xi' an Jiaotong University, Shaanxi (China)

    2012-04-15

    An experimental study of heat transfer characteristics of steam in a square channel (simulating a gas turbine blade cooling passage) with two opposite surfaces roughened by 60 deg parallel ribs was performed. The ranges of key governing parameters were: Reynolds numbers (Re) based on the channel hydraulic diameter (30000-140000), entry gauge pressure (0.2Mpa-0.5Mpa), heat flux of heat transfer surface area (5kWm{sup -2}-20kWm{sup -2}), and steam superheat (13 .deg. C-51 .deg. C). The test channel length was 1000mm, while the rib spacing (p/e) was 10, and the ratio of rib height (e) to hydraulic diameter (D) was 0.048. The test channel was heated by passing current through stainless steel walls instrumented with thermocouples. The local heat transfer coefficients on the ribbed wall from the channel entrance to the fully developed regions were measured. The semi-empirical correlation was fitted out by using the average Nusselt numbers in the fully developed region to cover the range of Reynolds number. The correlation can be used in the design of new generation of gas turbine blade cooled by steam.

  7. Analysis of the location for peak heating in CHP based combined district heating systems

    International Nuclear Information System (INIS)

    Wang, Haichao; Lahdelma, Risto; Wang, Xin; Jiao, Wenling; Zhu, Chuanzhi; Zou, Pinghua

    2015-01-01

    Combined heat and power (CHP) is the main technology for providing the base load of district heating in China. However, CHP is not efficient for providing the peak load; instead, a peak boiler with high efficiency could be used to compensate the peak load. This paper studies how the location of the peak boiler can affect the energy efficiency and economic performance of such CHP based combined district heating system. Firstly, the connection mode and the control strategy for different peak heating locations are analyzed. Then the effect of the peak boiler's location on the initial investment of the network and the cost for distributing heat is studied. The objective is to place the peak boiler in a location where the overall costs are the smallest. Following this rule, the results indicate that the peak boiler should be located at the CHP plant if that allows using cheaper ‘self-use electricity’ in CHP for distributing the heat. However, if the market electricity price is used everywhere, or if energy efficiency is more emphasized, the location of the peak boiler should be closer to the users with dense heat loads. - Highlights: • Location for peak heating in the CHP based combined DH system is studied. • Regulation or control strategies for combined DH are summarized. • The heat load duration curve for combined DH is demonstrated. • Network design for combined DH with peak boiler outside of the CHP is analyzed

  8. A Steam Utility Network Model for the Evaluation of Heat Integration Retrofits – A Case Study of an Oil Refinery

    Directory of Open Access Journals (Sweden)

    Sofie Marton

    2017-12-01

    Full Text Available This paper presents a real industrial example in which the steam utility network of a refinery is modelled in order to evaluate potential Heat Integration retrofits proposed for the site. A refinery, typically, has flexibility to optimize the operating strategy for the steam system depending on the operation of the main processes. This paper presents a few examples of Heat Integration retrofit measures from a case study of a large oil refinery. In order to evaluate expected changes in fuel and electricity imports to the refinery after implementation of the proposed retrofits, a steam system model has been developed. The steam system model has been tested and validated with steady state data from three different operating scenarios and can be used to evaluate how changes to steam balances at different pressure levels would affect overall steam balances, generation of shaft power in turbines, and the consumption of fuel gas.

  9. District heating from a community perspective : the Aboriginal experience

    Energy Technology Data Exchange (ETDEWEB)

    Wapachee, L. [Ouje-Bougoumou First Nation, Ouje-Bougoumou, PQ (Canada)

    2010-07-01

    This presentation discussed an alternative energy system that was incorporated into the planning and development of a new permanent village for the Ouje-Bougoumou Cree. The history of the Ouje-Bougoumou Cree people and its involvement with industry and governmental bodies were described at length. To provide for the long-term financial requirements of the community in a manner in harmony with Cree environmental philosophy, an appropriate alternative energy system was incorporated into the village architecture. Biomass district heating is an alternative energy system that uses a single source of energy to heat the community's houses and buildings. In this case, sawdust fuel is used to heat water, which is pumped through underground pipes to heat buildings before it cycles back to the plant for reheating. This system converts a waste product into usable energy, capturing and recycling energy while replacing conventional sources, such as oil, gas, or hydroelectricity, and creating local employment. Heat is the largest portion of the community's energy requirement. 11 figs., 1 tab.

  10. Design of SES-10 nuclear reactor for district heating

    International Nuclear Information System (INIS)

    Cuttler, J.M.

    1991-03-01

    The SES-10 units are unpressurized, pool-type nuclear reactors of 10MW rating, designed for supplying energy to hot water district heating systems, economically and without pollution. Water for heat distribution is brought to a maximum temperature of 85 degrees C. Conventional heating units supplement the output from SES-10 units for peak load and during maintenance. The SES-10 is housed in a low-cost building, with a double-walled pool in the ground. A naturally circulating primary system and a pumped secondary system transport heat from the reactor to the distribution system. The unit is fully automated and easy to maintain. Because of the many active and passive safety features, it is feasible to license the SES-10 for operation in a city and easy to explain it to the public for their acceptance. The core lasts approximately 43 months at a capacity factor of 70%, and the cost of heat is expected to be 2 to 2.5 cents/kWh

  11. Design of SES-10 nuclear reactor for district heating

    International Nuclear Information System (INIS)

    Cuttler, J.M.

    1991-01-01

    The SES-10 units are unpressurized, pool-type nuclear reactors of 10 MW rating, designed for supplying energy to hot water district heating systems, economically and without pollution. Water for heat distribution is brought to a maximum temperature of 85 o C. Conventional heating units supplement the output from SES-10 units for peak load and during maintenance. The SES-10 is housed in a low-cost building, with a double-walled pool in the ground. A naturally circulating primary system and a pumped secondary system transport heat from the reactor to the distribution system. The unit is fully automated and easy to maintain. Because of the many active and passive safety features, it is feasible to license the SES-10 for operation in a city and easy to explain it to the public for their acceptance. The core lasts approximately 43 months at a capacity factor of 70%, and the cost of heat is expected to be 2 to 2.5 cents/kWh. (author) 8 figs

  12. The role of district heating in future renewable energy systems

    DEFF Research Database (Denmark)

    Lund, Henrik; Möller, Bernd; Mathiesen, Brian Vad

    2010-01-01

    Based on the case of Denmark, this paper analyses the role of district heating in future Renewable Energy Systems. At present, the share of renewable energy is coming close to 20 per cent. From such point of departure, the paper defines a scenario framework in which the Danish system is converted...... to 100 per cent Renewable Energy Sources (RES) in the year 2060 including reductions in space heating demands by 75 per cent. By use of a detailed energy system analysis of the complete national energy system, the consequences in relation to fuel demand, CO2 emissions and cost are calculated for various...... as in a potential future system based 100 per cent on renewable energy....

  13. Expieriences On Low-Temperature District Heating In Lystrup – Denmark

    DEFF Research Database (Denmark)

    Thorsen, Jan Eric; Christiansen, Christian Holm; Brand, Marek

    2011-01-01

    by implementing Low-temperature district heating systems. Demonstration cases in EnergyFlexHouse and Boligforeningen Ringgården” EUDP 2011. A key challenge for optimum and competitive district heating (DH) system operation is reducing heat loss in networks. Today building regulations in most countries demand...

  14. Possibility of using adsorption refrigeration unit in district heating network

    Directory of Open Access Journals (Sweden)

    Grzebielec Andrzej

    2015-09-01

    Full Text Available Adsorption refrigeration systems are able to work with heat sources of temperature starting with 50 °C. The aim of the article is to determine whether in terms of technical and economic issues adsorption refrigeration equipment can work as elements that produce cold using hot water from the district heating network. For this purpose, examined was the work of the adsorption air conditioning equipment cooperating with drycooler, and the opportunities offered by the district heating network in Warsaw during the summer. It turns out that the efficiency of the adsorption device from the economic perspective is not sufficient for production of cold even during the transitional period. The main problem is not the low temperature of the water supply, but the large difference between the coefficients of performance, COPs, of adsorption device and a traditional compressor air conditioning unit. When outside air temperature is 25 °C, the COP of the compressor type reaches a value of 4.49, whereas that of the adsorption device in the same conditions is 0.14. The ratio of the COPs is 32. At the same time ratio between the price of 1 kWh of electric power and 1 kWh of heat is only 2.85. Adsorption refrigeration equipment to be able to compete with compressor devices, should feature COPads efficiency to be greater than 1.52. At such a low driving temperature and even changing the drycooler into the evaporative cooler it is not currently possible to achieve.

  15. North–South debate on district heating: Evidence from a household survey

    International Nuclear Information System (INIS)

    Guo, Jin; Huang, Ying; Wei, Chu

    2015-01-01

    There has been a long debate on whether South China should supply district heating for the residential sector, a system that is widely used in North China. The major concern is that it may further accelerate China's energy demand. Using a unique urban household level dataset, the China Residential Energy Consumption Survey (CRECS), we investigate residential energy consumption for heating and examine the energy intensity and energy cost of distributed heating in South China and district heating in North China during the 2012 heating season. Our results show that the total energy consumption for distributed heating system users in southern cities is significantly lower than for users of district heating systems in northern cities. However, when accounting for the heating area and heating season, the distributed heating households in the South consumed 32% more energy and paid 189% higher cost per unit area and per hour, but had lower comfort than district heating users in the North. These findings suggest promoting the district heating market in appropriate areas in South China. This not only can improve residential welfare, but also can indirectly reduce energy consumption and financial burdens. - Highlights: • The debate on whether Southern China apply district heating is present. • The household data in 2012 is used to compare the energy efficient and cost. • South resident use more energy and higher cost but less comfort than North. • Government should not prevent the district heating market.

  16. Steady-state heat transfer in an inverted U-tube steam generator

    International Nuclear Information System (INIS)

    Boucher, T.J.

    1986-01-01

    Experimental results are presented involving U-tube steam generator tube bundle local heat transfer and fluid conditions during steady-state, full-power operations performed at high temperatures and pressures with conditions typical of a pressurized water reactor (15.0 MPa primary pressure, 600 K hot-leg fluid temperatures, 6.2 MPa secondary pressure). The MOD-2C facility represents the state-of-the-art in measurement of tube local heat transfer data and average tube bundle secondary fluid density at several elevations, which allows an estimate of the axial heat transfer and void distributions during steady-state and transient operations. The method of heat transfer data reduction is presented and the heat flux, secondary convective heat transfer coefficient, and void fraction distributions are quantified for steady-state, full-power operations

  17. Layout of an internally heated gas generator for the steam gasification of coal

    International Nuclear Information System (INIS)

    Feistel, P.P.; Duerrfeld, R.; Heck, K.H. van; Juentgen, H.

    1975-01-01

    Industrial-scale steam gasification of coal using heat from high temperature reactors requires research and development on allothermal gas generators. Bergbau-Forschung GmbH, Essen, does theoretical and experimental work in this field. The experiments deal with reaction kinetics, heat transfer and material tests. Their significance for the layout of a full-scale gas generator is shown. Including material specifications, the feasibility of a gasifier, characterized by a fluid bed volume of 318 m 3 and a heat transferring area of 4000 m 2 , results. The data, now available, are used to determine the gasification throughput from the heat balance, i.e. the equality of heat consumed and heat transferred. Throughputs of about 50 t/hr of coal are possible for a single gas generator, the helium outlet temperature of the HTR being 950 0 C/ Bergbau-Forschung has commissioned a medium-scale pilot plant (200 kg/hr). (Auth.)

  18. Thermodynamic calculation of a district energy cycle

    International Nuclear Information System (INIS)

    Hoehlein, B.; Bauer, A.; Kraut, G.; Scherberich, F.D.

    1975-08-01

    This paper presents a calculation model for a nuclear district energy circuit. Such a circuit means the combination of a steam reforming plant with heat supply from a high-temperature nuclear reactor and a methanation plant with heat production for district heating or electricity production. The model comprises thermodynamic calculations for the endothermic methane reforming reaction as well as the exothermic CO-hydrogenation in adiabatic reactors and allows the optimization of the district energy circuit under consideration. (orig.) [de

  19. Cogeneration and District Heating. Best Practices for Municipalities

    International Nuclear Information System (INIS)

    Nuorkivi, A.; Constantinescu, T.

    2005-01-01

    District heating (DH) and cogeneration of heat power (CHP) are well known technologies in the energy business and are often included in municipal policies as well. Some of the major benefits of DH and CHP are less known and the barriers faced by further development of DH and CHP are substantial. The main barriers are institutional. Municipalities can play a powerful role in facilitating local DH and CHP development in order to achieve the economic and environmental benefits of DH and CHP. This report is produced to assist municipalities in promoting efficient and environmental beneficial DH and CHP. The focus of the report is on the economies in transition, where the institutional barriers are acute. The report addresses the issues of organisational framework, price regulation and financing, energy demand, rehabilitation of DH systems and benchmarking of DH and CHP. The municipality may influence the DH development by a number of means. The most important means, discussed in the various chapters of the report, are: (1) City planning impacts on the heat load density. A high density is an important factor for the economics of DH and city planning may promote DH in areas with high density and individual heating modes in the areas with low density; (2) Managing the building stock owned by the municipality to join the DH system and paying for the heating services; (3) Setting strategic goals for the District Heating Enterprise (DHE), which they usually own, regarding the quality and the costs of heating. The DHE shall be given sufficient resources to work towards such goals; (4) Providing guarantees for financing DH rehabilitation and development. The DHE may not have access to commercial credits without municipal guarantees; and, (5) Supporting the DHE management by giving operational independence, supervising the management performance regularly and encouraging the co-operation with other DHEs and equipment manufacturers. Examples provided in the report of

  20. Test and evaluation of Alco/BLH prototype sodium-heated steam generator. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, C.J.; Auge, L.J.; Cho, S.M.; Hanna, R.W.; Prevost, J.R.; Steger, N.A.; Wagner, R.K.

    1971-01-31

    A 30-Mwt prototype sodium-to-sodium intermediate heat exchanger and a 30-Mwt prototype sodium-heated steam generator were tested in combined operation in its Sodium Components Test Installation. This report contains the results of test and evaluation of the steam generator. During plant performance tests, performance degradation was observed, which resulted in the initiation of a diagnostic test series. This test series revealed that under certain operating conditions, the thermohydraulic characteristic of the steam generator changed either suddenly or gradually, resulting in overall performance degradation. A structural failure, requiring retirement of the unit, occurred before the diagnostic test series and analytical support effort were completed. This report describes the thermohydraulic and structural performance, including the structural failures, and related evaluation analyses of the Alco/BLH prototype steam generator performed prior to termination of the test and evaluation program. In addition, the report presents a post-test examination plan to obtain data that could possibly explain the cause of performance anomalies and structural failures experienced during testing.

  1. Predicting the Heat Consumption in District Heating Systems using Meteorological Forecasts

    DEFF Research Database (Denmark)

    Nielsen, Henrik Aalborg, orlov 31.07.2008; Madsen, Henrik

    that meteorological forecasts are available on-line. Such a service has recently been introduced by the Danish Meteorological Institute. However, actual meteorological forecasts has not been available for the work described here. Assuming the climate to be known the mean absolute relative prediction error for 72 hour......Methods for on-line prediction of heat consumption in district heating systems hour by hour for horizons up to 72 hours are considered in this report. Data from the district heating system Vestegnens Kraftvarmeselskab I/S is used in the investigation. During the development it has been assumed......, this is somewhat contrary to practice. The work presented is a demonstration of the value of the so called gray box approach where theoretical knowledge about the system under consideration is combined with information from measurements performed on the system in order to obtain a mathematical description...

  2. Natural refrigerants. Future heat pumps for district heating; Naturliga koeldmedier. Framtida vaermepumpar foer fjaerrvaerme

    Energy Technology Data Exchange (ETDEWEB)

    Ingvarsson, Paul; Steen Ronnermark, Ingela [Fortum Teknik och Miljoe AB, Stockholm (Sweden); Eriksson, Marcus [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Chemical Engineering and Environmental Science

    2004-01-01

    International work on refrigerants is aiming at phasing out HFC. The solution might be natural refrigerants. Within 15-20 years, when present heat pumps for district heating in Sweden are likely not in service any longer, it might still be good economy to install new heat pumps since only the machines need to be replaced. This report describes the possibilities to use natural refrigerants. A first screening resulted in further study on some hydrocarbons, ammonia and carbon dioxide. Water was considered to require too large volumes. In present plants it is practically not possible to use any natural refrigerants, partly because the compressors are not adapted. In new plants the situation is different. Today it is technically possible to install new heat pumps in the studied size, 15 MW{sub th}, using ammonia or hydrocarbons as refrigerant. But likely it is very difficult to get permits from authorities since the refrigerants are toxic or highly flammable. There is substantial international research on using carbon dioxide, and this refrigerant is also used in some applications. Carbon dioxide is used at high pressure and in a trans-critical process. Surprisingly, it turned out that one compressor manufacturer considers it possible to supply a heat pump for district heating within 5 years. This development has taken place in Russia, mainly for domestic use. Thus, within 15 to 20 years there will probably exist a technique where carbon dioxide is used. However, more development is needed. Additionally, low district heating return temperatures are also needed to get an acceptable COP. The investment cost for a heat pump installation is considered to be approx. 30 % higher when using ammonia or propane compared to using R134a. When using carbon dioxide there is in the longer run potential to get lower cost than for R134a. The COPs are almost identical if the systems are properly designed. In the carbon dioxide case the COP is somewhat lower, but has a potential for

  3. Study of condensation heat transfer following a main steam line break inside containment

    Energy Technology Data Exchange (ETDEWEB)

    Cho, J.H.; Elia, F.A. Jr.; Lischer, D.J. [Stone & Webster Engineering Corporation, Boston, MA (United States)

    1995-09-01

    An alternative model for calculating condensation heat transfer following a main stream line break (MSLB) accident is proposed. The proposed model predictions and the current regulatory model predictions are compared to the results of the Carolinas Virginia Tube Reactor (CVTR) test. The very conservative results predicted by the current regulatory model result from: (1) low estimate of the condensation heat transfer coefficient by the Uchida correlation and (2) neglecting the convective contribution to the overall heat transfer. Neglecting the convection overestimates the mass of steam being condensed and does not permit the calculation of additional convective heat transfer resulting from superheated conditions. In this study, the Uchida correlation is used, but correction factors for the effects of convection an superheat are derived. The proposed model uses heat and mass transfer analogy methods to estimate to convective fraction of the total heat transfer and bases the steam removal rate on the condensation heat transfer portion only. The results predicted by the proposed model are shown to be conservative and more accurate than those predicted by the current regulatory model when compared with the results of the CVTR test. Results for typical pressurized water reactors indicate that the proposed model provides a basis for lowering the equipment qualification temperature envelope, particularly at later times following the accident.

  4. High efficiency, quasi-instantaneous steam expansion device utilizing fossil or nuclear fuel as the heat source

    International Nuclear Information System (INIS)

    Claudio Filippone

    1999-01-01

    Thermal-hydraulic analysis of a specially designed steam expansion device (heat cavity) was performed to prove the feasibility of steam expansions at elevated rates for power generation with higher efficiency. The steam expansion process inside the heat cavity greatly depends on the gap within which the steam expands and accelerates. This system can be seen as a miniaturized boiler integrated inside the expander where steam (or the proper fluid) is generated almost instantaneously prior to its expansion in the work-producing unit. Relatively cold water is pulsed inside the heat cavity, where the heat transferred causes the water to flash to steam, thereby increasing its specific volume by a large factor. The gap inside the heat cavity forms a special nozzle-shaped system in which the fluid expands rapidly, accelerating toward the system outlet. The expansion phenomenon is the cause of ever-increasing fluid speed inside the cavity system, eliminating the need for moving parts (pumps, valves, etc.). In fact, the subsequent velocity induced by the sudden fluid expansion causes turbulent conditions, forcing accelerating Reynolds and Nusselt numbers which, in turn, increase the convective heat transfer coefficient. When the combustion of fossil fuels constitutes the heat source, the heat cavity concept can be applied directly inside the stator of conventional turbines, thereby greatly increasing the overall system efficiency

  5. Annex to Solar heat storages in district heating networks. Comprehensive list of Danish literature and R and D projects

    Energy Technology Data Exchange (ETDEWEB)

    Ellehauge, K. (Ellehauge og Kildemoes, AArhus (DK)); Engberg Pedersen, T. (COWI A/S, Kgs. Lyngby (DK))

    2007-07-15

    This annex relates to the report 'Solar heat storages in district heating networks', which has been elaborated to inform about the Danish experiences and findings on the use of central solar heating plants in district heating networks, especially with the focus on the development of the storage part of the systems. The report has been funded as part of the IEE PREHEAT cooperation and by Energinet.dk, project no. 2006-2-6750. (au)

  6. Margins in Swedish district heating systems; Marginaler i Fjaerrvaermesystem

    Energy Technology Data Exchange (ETDEWEB)

    Selinder, Patrik; Zinko, Heimo [ZW Energiteknik AB, Nykoeping (Sweden)

    2003-03-01

    It can be assumed on good reasons that the Swedish district heating nets are designed with relatively large margins concerning the transportable power. This is done historically to be able to transport the necessary power that can be called for on the coldest winter days but which occur rarely and also due to the former (until 2001) applied recommendations for the dimensioning of hot water flows. The aim of this project was to investigate the possibilities of reducing the connecting power to customers, both from a technical and from the customer point of view. The heating system of a building in Sweden is normally dimensioned according to a certain outdoor air temperature (DUT in Swedish). According to the Swedish Building Code, DUT20 is defined for a given location in such a way that if the heating system is designed for this temperature, the room temperature is allowed to decrease by 3 deg C in the average once in 20 years. That means that for economical reasons, a power deficiency is accounted for in the case of strong cold. The value of DUT is depending on the thermal inertia of the building. Buildings with high thermal inertia can have a higher DUT and vice versa. A reduced system size can in principle mean smaller size of pipes and consumer substations and more power available for additional customers to be connected. In principle, that means a more profitable district heating operation. Besides costs, another problem with oversized capacities are possible operational problems due to slow dynamic system responses, for instance at restarting occasions after a pump stop. A smaller valve size will result in a better system dynamic and may result in a more compliant system operation and increased delivery quality. By choosing just right DUT for every building and abandoning safety margins, it is shown in the report that the connecting power can be reduced in especially medium light to heavy buildings with larger time constants. However, this also means that the

  7. Air source absorption heat pump in district heating: Applicability analysis and improvement options

    International Nuclear Information System (INIS)

    Wu, Wei; Shi, Wenxing; Li, Xianting; Wang, Baolong

    2015-01-01

    Highlights: • Applicability of air source absorption heat pump (ASAHP) district heating is studied. • Return temperature and energy saving rate (ESR) in various conditions are optimized. • ASAHP is more suitable for shorter distance or lower temperature district heating. • Two options can reduce the primary return temperature and improve the applicability. • The maximum ESR is improved from 13.6% to 20.4–25.6% by compression-assisted ASAHP. - Abstract: The low-temperature district heating system based on the air source absorption heat pump (ASAHP) was assessed to have great energy saving potential. However, this system may require smaller temperature drop leading to higher pump consumption for long-distance distribution. Therefore, the applicability of ASAHP-based district heating system is analyzed for different primary return temperatures, pipeline distances, pipeline resistances, supplied water temperatures, application regions, and working fluids. The energy saving rate (ESR) under different conditions are calculated, considering both the ASAHP efficiency and the distribution consumption. Results show that ASAHP system is more suitable for short-distance district heating, while for longer-distance heating, lower supplied hot water temperature is preferred. In addition, the advantages of NH 3 /H 2 O are inferior to those of NH 3 /LiNO 3 , and the advantages for warmer regions and lower pipeline resistance are more obvious. The primary return temperatures are optimized to obtain maximum ESRs, after which the suitable distances under different acceptable ESRs are summarized. To improve the applicability of ASAHP, the integration of cascaded heat exchanger (CHX) and compression-assisted ASAHP (CASAHP) are proposed, which can reduce the primary return temperature. The integration of CHX can effectively improve the applicability of ASAHP under higher supplied water temperatures. As for the utilization of CASAHP, higher compression ratio (CR) is better in

  8. Exergy Steam Drying and Energy Integration

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Prem; Muenter, Claes (Exergy Engineering and Consulting, SE-417 55 Goeteborg (Sweden)). e-mail: verma@exergyse.com

    2008-10-15

    Exergy Steam Drying technology has existed for past 28 years and many new applications have been developed during this period. But during past few years the real benefits have been exploited in connection with bio-fuel production and energy integration. The steam dryer consists of a closed loop system, where the product is conveyed by superheated and pressurised carrier steam. The carrier steam is generated by the water vapours from the product being dried, and is indirectly superheated by another higher temperature energy source such as steam, flue gas, thermal oil etc. Besides the superior heat transfer advantages of using pressurised steam as a drying medium, the energy recovery is efficient and simple as the recovered energy (80-90%) is available in the form of steam. In some applications the product quality is significantly improved. Examples presented in this paper: Bio-Combine for pellets production: Through integration of the Exergy Steam Dryer for wood with a combined heat and power (CHP) plant, together with HP steam turbine, the excess carrier steam can be utilised for district heating and/or electrical power production in a condensing turbine. Bio-ethanol production: Both for first and second generation of ethanol can the Exergy process be integrated for treatment of raw material and by-products. Exergy Steam Dryer can dry the distillers dark grains and solubles (DDGS), wood, bagasse and lignin. Bio-diesel production: Oil containing seeds and fruits can be treated in order to improve both the quality of oil and animal feed protein, thus minimizing further oil processing costs and increasing the sales revenues. Sewage sludge as bio-mass: Municipal sewage sludge can be considered as a renewable bio-fuel. By drying and incineration, the combustion heat value of the sludge is sufficient for the drying process, generation of electrical energy and production of district heat. Keywords; Exergy, bio-fuel, bio-mass, pellets, bio-ethanol, biodiesel, bio

  9. Controller tuning of district heating networks using experiment design techniques

    International Nuclear Information System (INIS)

    Dobos, Laszlo; Abonyi, Janos

    2011-01-01

    There are various governmental policies aimed at reducing the dependence on fossil fuels for space heating and the reduction in its associated emission of greenhouse gases. DHNs (District heating networks) could provide an efficient method for house and space heating by utilizing residual industrial waste heat. In such systems, heat is produced and/or thermally upgraded in a central plant and then distributed to the end users through a pipeline network. The control strategies of these networks are rather difficult thanks to the non-linearity of the system and the strong interconnection between the controlled variables. That is why a NMPC (non-linear model predictive controller) could be applied to be able to fulfill the heat demand of the consumers. The main objective of this paper is to propose a tuning method for the applied NMPC to fulfill the control goal as soon as possible. The performance of the controller is characterized by an economic cost function based on pre-defined operation ranges. A methodology from the field of experiment design is applied to tune the model predictive controller to reach the best performance. The efficiency of the proposed methodology is proven throughout a case study of a simulated NMPC controlled DHN. -- Highlights: → To improve the energetic and economic efficiency of a DHN an appropriate control system is necessary. → The time consumption of transitions can be shortened with the proper control system. → A NLMPC is proposed as control system. → The NLMPC is tuned by utilization of simplex methodology, using an economic oriented cost function. → The proposed NLMPC needs a detailed model of the DHN based on the physical description.

  10. Comparison of Heat Transfer Fluid and Direct Steam Generation technologies for Integrated Solar Combined Cycles

    International Nuclear Information System (INIS)

    Rovira, Antonio; Montes, María José; Varela, Fernando; Gil, Mónica

    2013-01-01

    At present time and in the medium term, Solar Thermal Power Plants are going to share scenario with conventional energy generation technologies, like fossil and nuclear. In such a context, Integrated Solar Combined Cycles (ISCCs) may be an interesting choice since integrated designs may lead to a very efficient use of the solar and fossil resources. In this work, different ISCC configurations including a solar field based on parabolic trough collectors and working with the so-called Heat Transfer Fluid (HTF) and Direct Steam Generation (DSG) technologies are compared. For each technology, four layouts have been studied: one in which solar heat is used to evaporate part of the high pressure steam of a bottoming Rankine cycle with two pressure levels, another that incorporates a preheating section to the previous layout, the third one that includes superheating instead of preheating and the last one including both preheating and superheating in addition to the evaporation. The analysis is made with the aim of finding out which of the different layouts reaches the best performance. For that purpose, three types of comparisons have been performed. The first one assesses the benefits of including a solar steam production fixed at 50 MW th . The second one compares the configurations with a standardised solar field size instead of a fixed solar steam production. Finally, the last one consists on an even more homogeneous comparison considering the same steam generator size for all the configurations as well as standardised solar fields. The configurations are studied by mean of exergy analyses. Several figures of merit are used to correctly assess the configurations. Results reveal that the only-evaporative DSG configuration becomes the best choice, since it benefits of both low irreversibility at the heat recovery steam generator and high thermal efficiency in the solar field. Highlights: ► ISCC configurations with DSG and HTF technologies are compared. ► Four

  11. Evaluation of heat transfer tube failure propagation due to sodium-water reaction in steam generator

    International Nuclear Information System (INIS)

    Nei, Hiromichi

    1978-01-01

    An evaluation was made of heat transfer tube failure propagation due to sodium-water reaction wastage in a sodium heated steam generator, by comparing an empirically derived wastage equation with leak detector responses. The experimental data agreed well with the wastage equation even for different values of distance-to-nozzle diameter ratio, though the formula had been based on wastage data obtained for only one given distance. The time taken for failure propagation was estimated for a prototype steam generator, and compared with the responses characteristics of acoustic detectors and level gages. It was found that there exists a range of leak rate between 0.5 and 100 g/sec, where the level gage can play a useful role in leak detection. The acoustic detector can be expected to respond more rapidly than the cover gas pressure gage, if noise is kept below ten times the value observed in an experimental facility, SWAT-2. (auth.)

  12. Composite electric generator equipped with steam generator for heating reactor coolant

    International Nuclear Information System (INIS)

    Watabe, Masaharu; Soman, Yoshindo; Kawanishi, Kohei; Ota, Masato.

    1997-01-01

    The present invention concerns a composite electric generator having coolants, as a heating source, of a PWR type reactor or a thermonuclear reactor. An electric generator driving gas turbine is disposed, and a superheater using a high temperature exhaust gas of the gas turbine as a heating source is disposed, and main steams are superheated by the superheater to elevate the temperature at the inlet of the turbine. This can increase the electric generation capacity as well as increase the electric generation efficiency. In addition, since the humidity in the vicinity of the exit of the steam turbine is reduced, occurrence of loss and erosion can be suppressed. When cooling water of the thermonuclear reactor is used, the electric power generated by the electric generator driven by the gas turbine can be used upon start of the thermonuclear reactor, and it is not necessary to dispose a large scaled special power source in the vicinity, which is efficient. (N.H.)

  13. Heat supply analysis of steam reforming hydrogen production process in conventional and nuclear

    International Nuclear Information System (INIS)

    Siti Alimah; Djati Hoesen Salimy

    2015-01-01

    Tile analysis of heat energy supply in the production of hydrogen by natural gas steam reforming process has been done. The aim of the study is to compare the energy supply system of conventional and nuclear heat. Methodology used in this study is an assessment of literature and analysis based on the comparisons. The study shows that the heat sources of fossil fuels (natural gas) is able to provide optimum operating conditions of temperature and pressure of 850-900 °C and 2-3 MPa, as well as the heat transfer is dominated by radiation heat transfer, so that the heat flux that can be achieved on the catalyst tube relatively high (50-80 kW/m"2) and provide high thermal efficiency of about 85 %. While in the system with nuclear energy, due to the demands of safety, process operating at less than optimum conditions of temperature and pressure of 800-850 °C and 4.5 MPa, as well as the heat transfer is dominated by convection heat transfer, so that the heat flux that can be achieved catalyst tube is relatively low (1020 kW/m"2) and it provides a low thermal efficiency of about 50 %. Modifications of reformer and heat utilization can increase the heat flux up to 40 kW/m"2 so that the thermal efficiency can reach 78 %. Nevertheless, the application of nuclear energy to hydrogen production with steam reforming process is able to reduce the burning of fossil fuels which has implications for the potential decrease in the rate of CO2 emissions into the environment. (author)

  14. Energy supply and urban planning projects: Analysing tensions around district heating provision in a French eco-district

    International Nuclear Information System (INIS)

    Gabillet, Pauline

    2015-01-01

    Through the analysis of energy supply choices, this article explores the way in which energy priorities and their climate-related features are incorporated into urban public policy. These choices must take account of different factors, as is the case with district heating, which is justified as a vehicle of renewable energy while subject to pressure in eco-districts because its techno-economic balances are destabilised by falls in demand. Our study focuses particularly on the city of Metz (France), which has chosen district heating as the primary source for provision for the municipal area and for its first eco-district. We analyse the tensions within these choices, with particular attention to the way in which they are negotiated inside municipal departments and with the local energy operator. This enables us to explore the tensions in defining the scale that governs decisions and the linkages between energy-related and urban priorities. - Highlights: • Analyses of tensions in the choice of energy supplies for eco-districts. •District heating networks can be vehicles of renewable energy. • District heating networks are threatened by drops in energy consumption. • Energy supply issues oppose urban planning and energy policy in municipal departments. • Technical and financial adjustments can be made by the municipality to justify its energy choices

  15. Sensitivity of district heating system operation to heat demand reductions and electricity price variations: A Swedish example

    International Nuclear Information System (INIS)

    Åberg, M.; Widén, J.; Henning, D.

    2012-01-01

    In the future, district heating companies in Sweden must adapt to energy efficiency measures in buildings and variable fuel and electricity prices. Swedish district heating demands are expected to decrease by 1–2% per year and electricity price variations seem to be more unpredictable in the future. A cost-optimisation model of a Swedish local district heating system is constructed using the optimisation modelling tool MODEST. A scenario for heat demand changes due to increased energy efficiency in buildings, combined with the addition of new buildings, is studied along with a sensitivity analysis for electricity price variations. Despite fears that heat demand reductions will decrease co-generation of clean electricity and cause increased global emissions, the results show that anticipated heat demand changes do not increase the studied system's primary energy use or global CO 2 emissions. The results further indicate that the heat production plants and the fuels used within the system have crucial importance for the environmental impact of district heat use. Results also show that low seasonal variations in electricity price levels with relatively low winter prices promote the use of electric heat pumps. High winter prices on the other hand promote co-generation of heat and electricity in CHP plants. -- Highlights: ► A MODEST optimisation model of the Uppsala district heating system is built. ► The impact of heat demand change on heat and electricity production is examined. ► An electricity price level sensitivity analysis for district heating is performed. ► Heat demand changes do not increase the primary energy use or global CO 2 emissions. ► Low winter prices promote use of electric heat pumps for district heating production.

  16. Experimental investigation of reflux condensation heat transfer in PWR steam generator tubes in the presence of noncondensible gases

    Energy Technology Data Exchange (ETDEWEB)

    Vierow, Karen; Wu, Tiejun [Purdue Univ., West Lafayette (United States); Nagae, Takashi [Institute of Nuclear Safety System, Tokyo (Japan)

    2003-07-01

    Under certain circumstances in a Pressurized Water Reactor (PWR), the coolant system may be in a partially drained state and reflux condensation in the steam generator U-tubes can be the major heat removal mechanism. Noncondensable gases may be present and would degrade the heat transfer rate. If heat removal rates are insufficient, this situation could lead to core boil-off, fuel rod heatup, and eventually core damage. The Institute of Nuclear Safety System, Inc. (INSS) and the Nuclear Heat Transfer Systems Laboratory at Purdue University have begun a cooperative research program to investigate the effectiveness of reflux condensation in PWR steam generator U-tubes in the presence of noncondensable gases. The final objectives are to provide local heat transfer data for development of methods to analyze reflux condensation in PWR steam generator U-tubes and to investigate the potential for flooding. Key features of the experimental data reported herein are that they are local data under laminar steam/gas mixture and condensate film flow and they are taken from a test section with dimensions similar to an actual steam generator tube. Steady state data were obtained under various steam and air inlet flow rates and pressures. The data show the significant degrading effect of noncondensable gas on heat transfer coefficients. From the data, correlations for the reflux condensation local heat transfer coefficient and the local Nusselt number under laminar conditions were derived. These experiments are providing essential and unique fundamental data for development of methods to analyze reflux condensation.

  17. RELAP5 analysis of reflux condensation behavior in heat transfer tube bundle of a steam generator

    International Nuclear Information System (INIS)

    Minami, Noritoshi; Chikusa, Toshiaki; Nagae, Takashi; Murase, Michio

    2007-01-01

    In case of loss of the residual heat removal system and other alternative cooling methods under mid-loop operation during shutdown of the pressurized water reactor plant, reflux condensation in the steam generator (SG) may be an effective heat removal mechanism. In reflux condensation experiments 7.2c with injection of nitrogen gas using the BETHSY facility in France, which is a scale model of a pressurized water reactor plant, 34 heat transfer tubes were divided into two kinds of flow patterns, which were steam forward flow and nitrogen reverse flow. In this study, we simulated the BETHSY experiments using the transient analysis code RELAP5. Modifying calculation equations for interfacial friction force and wall friction force between the inlet plenum and heat transfer tubes, nitrogen reverse flow was successfully simulated. In calculations with alteration of the flow area ratio to two flow channels for the heat transfer tube bundle, the number of active tubes with the maximum nitrogen recirculation flow rate agreed rather well with the observed number of active tubes. In calculations with three flow channels for the heat transfer tube bundle, the average number of active tubes in several calculations with different flow area ratios of the three flow channels predicted the number of active tubes well. (author)

  18. The Swiss heating reactor (SHR) for district heating of small communities

    International Nuclear Information System (INIS)

    Burgsmueller, P.; Jacobi, A.Jr.; Jaeger, J.F.; Klaentschi, M.J.; Seifritz, W.; Vuillemier, F.; Wegmann, F.

    1987-01-01

    With fossil fuel running out in a foreseeable future, it is essential to develop substitution strategies. Some 40-50 % of the heat demand in industrial countries is below 120 degrees C, for space heating and warm water production, causing a corresponding fraction of air pollution by SO 2 and to a lesser extent NO x if fossil fuels are used. Yet, contemporary LWR technology makes it feasible to supply a district heating network without basically new reactor development. Units in the power range 10-50 MW are most suitable for Switzerland, both in respect of network size and of the democratic decision making structure. A small BWR for heating purpose is being developed by parts of the Swiss Industry and the Swiss Federal Institute for Reactor Research (EIR). The economic target of 100-120 SFr/MWh heat at the consumer's seems achievable. (author)

  19. Fluid induced structural vibrations in steam generators and heat exchangers

    International Nuclear Information System (INIS)

    Catton, I.; Adinolfi, P.; Alquaddoomi, O.

    2003-01-01

    Fluid-elastic instability (FEI) in tube bundle heat exchangers was studied experimentally. The motion of an array of 15 stainless steel vibrating tubes (Φ 25.4mm) in water cross-flow, suspended using stainless steel piano wire has been recorded with a CCD camera. The individual motion and relative motion of the tubes are reported and can be used for computational model validation. The relative displacement of the tubes allows identification of the most potentially damaging patterns of tube bundle vibration. A critical reduced velocity may be determined by specification of an allowable limit on tube motion amplitude. Measurements were made for various tube array configurations, tube natural frequencies and flow conditions. (author)

  20. Study on Relative COP Changes with Increasing Heat Input Temperatures of Double Effect Steam Absorption Chillers

    Directory of Open Access Journals (Sweden)

    Abd Majid Mohd Amin

    2016-01-01

    Full Text Available Absorption chillers at cogeneration plants generate chilled water using steam supplied by heat recovery steam generators. The chillers are mainly of double effect type. The COP of double effect varies from 0.7 to 1.2 depending on operation and maintenance practices of the chillers. Heat input to the chillers during operations could have impact on the COP of the chillers. This study is on relative COP changes with increasing the heat input temperatures for a steam absorption chiller at a gas fueled cogeneration plant. Reversible COP analysis and zero order model were used for evaluating COP of the chiller for 118 days operation period. Results indicate increasing COP trends for both the reversible COP and zero model COP. Although the zero model COP are within the range of double effect absorption chiller, it is not so for the actual COP. The actual COP is below the range of normal double effect COP. It is recommended that economic replacement analysis to be undertaken to assess the feasibility either to repair or replace the existing absorption chiller.

  1. Individual Heating systems vs. District Heating systems: What will consumers pay for convenience?

    International Nuclear Information System (INIS)

    Yoon, Taeyeon; Ma, Yongsun; Rhodes, Charles

    2015-01-01

    For Korea's two most popular apartment heating systems – Individual Heating (IH) and District Heating (DH), – user convenience rests heavily on location of the boiler, availability of hot water, administration of the system, and user control of indoor temperature. A double-bounded dichotomous choice method estimates consumer value for convenience, in a hypothetical market. Higher-income more-educated consumers in more expensive apartments prefer DH. Cost-conscious consumers, who use more electrical heating appliances and more actively adjust separate room temperatures, prefer IH. With willingness-to-pay (WTP) defined as the price ratio between IH and DH, 800 survey respondents indicate a WTP of 4.0% for DH over IH. IH users unfamiliar with DH expect little greater convenience (0.1% WTP), whereas the WTP for DH users runs to 7.9%, demonstrating consumer loyalty. Quantified estimates of consumer preference and convenience can inform design of a full-cost-plus pricing system with a price cap. Results here indirectly predict the effect of abolishing regulations that exclusively establish district heating zones. Strategies to foster the many external benefits of DH systems should stress not their lower cost, but convenience, comfort, and safety. Higher installation costs still hamper DH expansion, so policy-makers could set policies to lower cost barriers to entry. - Highlights: • District Heating (DH) and Individual Heating (IH) systems differ in user convenience. • Difference of convenience is evaluated by a double-bounded dichotomous choice method. • Consumers are willing to pay a 4.03–12.52% higher rate to use DH rather than IH. • Consumers with high living standards prefer DH to IH, and show high consumer loyalty. • Strategies to foster DH systems should stress DH convenience over its lower cost.

  2. District heating demonstration project. Swiecie, Poland. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-06-01

    In January 1997 the district heating company in Swiecie, Poland, was donated DKK 1.3 Mio. as a part of the environmental related energy sector programme by the Danish government for a demonstration project. The Danish consultancy company Carl Bro a/s was appointed to conduct the work. The project was finished in January 1999. The present final report outlines the activities of the demonstration project. The activities of the project were several. Carl Bro a/s elaborated tender documents and procured 79 heat meters for all the substrations in the city in order to prepare for the new energy law and a changed tariff system which was introduced in January 1999. Carl Bro a/s further supported ZEC Swiecie in the development of their new tariff system through information from Danish district heating companies. The demonstration project was designed in the first phase of the project. During the design period one engineer from Swiecie participated in a study tour to Denmark to learn about technical solutions to present problems in Poland. The training course focused on preparation of hot tap water. The site for the demonstation project was in the centre of Swiecie in a housing society located in Wojska Polskiego. The blocks 75 and 75A were selected for modernisation of the substations, and block no. 73 was appointed as a reference block in which only a heat meter was installed. Further, block 75A was equipped with thermostatic valves at all the radiators in the flats. The registered savings during the monitoring period were between 7% and 14%, and an increased comfort in the flats was observed. The housing society`s board of directors were so pleased with the project that by their initiative block no. 77 was refurbished in the same way as the blocks covered by the demonstration project. However, the activities were extended with individual heat meters and the introduction of a new tariff system for the block. The energy savings from this project were substantial, and today

  3. Prospects for development of heat supply systems in high-rise districts

    Science.gov (United States)

    Zhila, Viktor; Solovyeva, Elena

    2018-03-01

    The article analyzes the main advantages and disadvantages of centralized and decentralized heat supply systems in high-rise districts. The main schemes of centralized heat supply systems are considered. They include centralized heat supply from boiler houses, centralized heat supply from autonomous heat sources, heat supply from roof boiler houses and door-to-door heating supply. For each of these variant, the gas distribution systems are considered and analyzed. These systems vary depending on the heat source location. For each of these systems, technical and economic indicators are taken into account, the analysis of which allows choosing the best option for districts where high-rise buildings predominate.

  4. Building Modelling Methodologies for Virtual District Heating and Cooling Networks

    Energy Technology Data Exchange (ETDEWEB)

    Saurav, Kumar; Choudhury, Anamitra R.; Chandan, Vikas; Lingman, Peter; Linder, Nicklas

    2017-10-26

    District heating and cooling systems (DHC) are a proven energy solution that has been deployed for many years in a growing number of urban areas worldwide. They comprise a variety of technologies that seek to develop synergies between the production and supply of heat, cooling, domestic hot water and electricity. Although the benefits of DHC systems are significant and have been widely acclaimed, yet the full potential of modern DHC systems remains largely untapped. There are several opportunities for development of energy efficient DHC systems, which will enable the effective exploitation of alternative renewable resources, waste heat recovery, etc., in order to increase the overall efficiency and facilitate the transition towards the next generation of DHC systems. This motivated the need for modelling these complex systems. Large-scale modelling of DHC-networks is challenging, as it has several components interacting with each other. In this paper we present two building methodologies to model the consumer buildings. These models will be further integrated with network model and the control system layer to create a virtual test bed for the entire DHC system. The model is validated using data collected from a real life DHC system located at Lulea, a city on the coast of northern Sweden. The test bed will be then used for simulating various test cases such as peak energy reduction, overall demand reduction etc.

  5. Restructuring and regulating district heating and cogeneration in transition economies

    International Nuclear Information System (INIS)

    Brendow, Klaus

    2004-01-01

    In summer 2004, the World Energy Council published a Study on 'Regulating district heating and cogeneration in central and eastern Europe'2, prepared by representatives from eleven economies in transition and two Nordic countries. The Task Force analysed twelve regulatory issues, country-by-country, on all internationally comparable basis. Regulatory progress on the road to more efficient, profitable, competitive and service-oriented heat supplies was described. Common concerns were identified: the need for independence of the regulator from policy and industry, improved coordination between central and local regulators and between environmental and energy authorities, access to grids, and a 'fair' sharing of CHP benefits among heat and electricity generation. Looking forward, the Task Force advocated a continued dialogue between decision makers, regulators, regulated industries and customers on: 1)the internalisation of DH/CHP benefits; 2)the future reduction of the density of regulation; 3) Joint implementation; 4)the compensation for public service obligations; 5)the elimination of old debt and stranded investments; 6) DH/CHP taxation; 7)privatisation; 8)the integration of DH/CHP in urban planning. A concluding WEC workshop in Moscow in March 2004 addressed recommendations to policy makers('Moscow Statement'). (Author)

  6. Passive cooling applications for nuclear power plants using pulsating steam-water heat pipes

    International Nuclear Information System (INIS)

    Aparna, J.; Chandraker, D.K.

    2015-01-01

    Gen IV reactors incorporate passive principles in their system design as an important safety philosophy. Passive safety systems use inherent physical phenomena for delivering the desired safe action without any external inputs or intrusion. The accidents in Fukushima have renewed the focus on passive self-manageable systems capable of unattended operation, for long hours even in extended station blackout (SBO) and severe accident conditions. Generally, advanced reactors use water or atmospheric air as their ultimate heat sink and employ passive principles in design for enhanced safety. This paper would be discussing the experimental results on pulsating steam water heat-pipe devices and their applications in passive cooling. (author)

  7. Flow-induced vibration analysis of heat exchanger and steam generator designs

    International Nuclear Information System (INIS)

    Pettigrew, M.J.; Sylvestre, Y.; Campagna, A.O.

    1977-08-01

    Tube and shell heat exchange components such as steam generators, heat exchangers and condensers are essential parts of CANDU nuclear power stations. Excessive flow-induced vibration may cause tube failures by fatigue or more likely by fretting-wear. Such failures may lead to station shutdowns that are very undesirable in terms of lost production. Hence good performance and reliability dictate a thorough flow-induced vibration analysis at the design stage. This paper presents our approach and techniques in this respect. (author)

  8. Comparison of district heating expansion potential based on consumer-economy or socio-economy

    DEFF Research Database (Denmark)

    Grundahl, Lars; Nielsen, Steffen; Lund, Henrik

    2016-01-01

    Recent studies show that a high share of district heating is an important part of a future sustainable energy system or smart energy system with a high renewable energy penetration. These studies also show socio-economic benefits of expanding the district heating coverage. However, in order...... to implement such an expansion, district heating needs to be economically feasible for the heat consumers. This aspect is often not investigated and hence it is unknown if calculations based on consumer-economy, where tax payment is included, will yield the same potential of expansion. This study identifies...... the differences in the expansion potential of district heating calculated with a socio-economic and a consumer-economic approach, respectively, in a case study of Denmark. By also investigating the consumer-economy of expanding district heating, a deeper insight is obtained of possible locations for expanding...

  9. Technological investigations and efficiency analysis of a steam heat exchange condenser: Conceptual design of a hybrid steam condenser

    OpenAIRE

    Kapooria, R K; Kumar, S; Kasana, K S

    2008-01-01

    Most of the electricity being produced throughout the world today is from steam power plants. At the same time, many other competent means of generating electricity have been developed viz. electricity from natural gas, MHD generators, biogas, solar cells, etc. But steam power plants will continue to be competent because of the use of water as the main working fluid which is abundantly available and is also reusable. The condenser remains among one of the key components of a steam power plant...

  10. Algorithmic acquisition of diagnostic patterns in district heating billing system

    International Nuclear Information System (INIS)

    Kiluk, Sebastian

    2012-01-01

    An application of algorithmic exploration of billing data is examined for fault detection, diagnosis (FDD) based on evaluation of present state and detection of unexpected changes in energy efficiency of buildings. Large data sets from district heating (DH) billing systems are used for construction of feature space, diagnostic rules and classification of the buildings according to their energy efficiency properties. The algorithmic approach automates discovering knowledge about common, thus accepted changes in buildings’ properties, in equipment and in habitants’ behavior reflecting progress in technology and life style. In this article implementation of Data Mining and Knowledge Discovery (DMKD) method in supervision system with exemplary results based on real data is presented. Crucial steps of data processing influencing diagnostic results are described in details.

  11. Efficient numerical method for district heating system hydraulics

    International Nuclear Information System (INIS)

    Stevanovic, Vladimir D.; Prica, Sanja; Maslovaric, Blazenka; Zivkovic, Branislav; Nikodijevic, Srdjan

    2007-01-01

    An efficient method for numerical simulation and analyses of the steady state hydraulics of complex pipeline networks is presented. It is based on the loop model of the network and the method of square roots for solving the system of linear equations. The procedure is presented in the comprehensive mathematical form that could be straightforwardly programmed into a computer code. An application of the method to energy efficiency analyses of a real complex district heating system is demonstrated. The obtained results show a potential for electricity savings in pumps operation. It is shown that the method is considerably more effective than the standard Hardy Cross method still widely used in engineering practice. Because of the ease of implementation and high efficiency, the method presented in this paper is recommended for hydraulic steady state calculations of complex networks

  12. Competition in the market for space heating. District heating as the infrastructure for competition among fuels and technologies

    International Nuclear Information System (INIS)

    Grohnheit, Poul Erik; Gram Mortensen, Bent Ole

    2003-01-01

    None of the EU directives on liberalisation of the electricity and gas markets are considering the district heating systems, although the district heating networks offer the possibility of competition between natural gas and a range of other fuels on the market for space heating. Cogeneration of electricity and heat for industrial processes or district heating is a technology option for increased energy efficiency and thus reduction of CO 2 emissions. In the mid-1990s less than 10% of the electricity generation in the European Union was combined production with significant variations among Member States. These variations are explained by different national legislation and relative power of institutions, rather than difference in industrial structure, climate or urban physical structure. The 'single energy carrier' directives have provisions that support the development of combined heat and power (CHP), but they do not support the development and expansion of the district heating infrastructure. The article is partly based on a contribution to the Shared Analysis Project for the European Commission DG Energy, concerning the penetration of CHP, energy saving, and renewables as instruments to meet the targets of the Kyoto Protocol within the liberalised European energy market. The quantitative and legal differences of the heat markets in selected Member States are described, and the consequences of the directives are discussed. Finally, we summarise the tasks for a European policy concerning the future regulation of district heating networks for CHP, emphasising the need for rules for a fair competition between natural gas and district heating networks

  13. On the method of heat exchange calculation for critical and postcritical regimes in sodium-water steam generators

    International Nuclear Information System (INIS)

    Khudasko, V.V.; Kardash, D.Yu.; Grachev, N.S.

    1986-01-01

    Technique for calculating heat exchange in sodium-water steam generators with provisions for steam-water flow non-equilibrium character and moisture additional evaporation in pipes is suggested. Zone of heat exchange crisis representing the zone of transition from developed boiling to postcritical zone is considered. Comparison of estimated and experimental data performed for the following ranges of steame generator parameters: pressure p=7.8-14.0 MPa, coolant flow rate ρw=350-1000 kg/(m 2 xs), inlet sodium temperature T=590-825 K shows their good agreement

  14. Estimation of transient heat flux density during the heat supply of a catalytic wall steam methane reformer

    Science.gov (United States)

    Settar, Abdelhakim; Abboudi, Saïd; Madani, Brahim; Nebbali, Rachid

    2018-02-01

    Due to the endothermic nature of the steam methane reforming reaction, the process is often limited by the heat transfer behavior in the reactors. Poor thermal behavior sometimes leads to slow reaction kinetics, which is characterized by the presence of cold spots in the catalytic zones. Within this framework, the present work consists on a numerical investigation, in conjunction with an experimental one, on the one-dimensional heat transfer phenomenon during the heat supply of a catalytic-wall reactor, which is designed for hydrogen production. The studied reactor is inserted in an electric furnace where the heat requirement of the endothermic reaction is supplied by electric heating system. During the heat supply, an unknown heat flux density, received by the reactive flow, is estimated using inverse methods. In the basis of the catalytic-wall reactor model, an experimental setup is engineered in situ to measure the temperature distribution. Then after, the measurements are injected in the numerical heat flux estimation procedure, which is based on the Function Specification Method (FSM). The measured and estimated temperatures are confronted and the heat flux density which crosses the reactor wall is determined.

  15. Technical safety management district heating; Technisches Sicherheitsmanagement (TSM) Fernwaerme. Ueberpruefung der Aufbau- und Ablauforganisation sowie der technischen Sicherheit von FVU

    Energy Technology Data Exchange (ETDEWEB)

    Brunn, H. von [Vereinigung Deutscher Elektrizitaetswerke e.V. (VDEW), Frankfurt am Main (Germany); Herbst, A. [DREWAG Stadtwerke Dresden GmbH (Germany); Hoffer, A. [EVH GmbH, Halle (Germany); Meigen, M. [Stadtwerke Leipzig (Germany); Siedler, W. [Stadtwerke Hannover AG (Germany)

    2003-08-01

    Anyone creating sources of danger in a public place must take proper precautions to prevent a hazard from actually arising. Work such as the construction or renovation of generating plants, pipe networks or district heat substations, the operation of heating installations and plants and the use of heating water and steam as media for the supply or district heating are potential sources of danger which may lead to accidents. The utility is liable for material damage and bodily harm. The only possible way of precluding liability is to prove that it has taken all possible measures for precluding risk at the outset within the organization itself, to the greatest possible extent. Not only must administration and line management be properly structured for this purpose, but administrative efficiency must also be demonstrated by a working system of delegation of tasks and responsibilities and the optimum organisation of processes and interfaces. (orig.) [German] Im AGFW-Arbeitsblatt FW 1000 'Anforderungen an die Qualifikation und die Organisation des technischen Bereichs von Fernwaermeversorgungsunternehmen' werden organisatorische, personelle sowie sicherheits- und betriebstechnische Mindestanforderungen fuer die Planung den Bau und den Betrieb von Nah- und Fernwaermeversorgungsanlagen beschrieben. Zur Bestaetigung der Anforderungserfuellung ist entweder eine Selbsteinschaetzung durch das Unternehmen oder die Ueberpruefung durch die AGFW vorgesehen. Hierfuer wurde ein Zertifizierungsverfahren entwickelt, das ab sofort von der gesamten Branche genutzt werden kann. (orig.)

  16. District heating marketing. Strategies in the heating market. 2. ed.; Fernwaerme-Marketing. Strategien im Waermemarkt

    Energy Technology Data Exchange (ETDEWEB)

    Marschalleck, Helmut [MVV Energie AG, Mannheim (Germany); Arndt, Andreas [EnBW Vertriebs- und Servicegesellschaft, Karlsruhe (Germany); Behm, Norman [Stadtwerke Rostock AG (Germany)] [and others

    2012-07-01

    The assistance in the strategic and operational planning of an individual marketing strategy in the district heating market is the focus of the book under consideration. Starting from the definition of the actual situation (market analysis and marketing potential) and the strategic goal, a marketing concept and a marketing mix (product policy, pricing policy, distribution policy as well as communication policy) is established. Subsequently, the tools of the marketing controlling (incoming orders and turnover, marketing key performance indicators, reporting, marketing audit) are described.

  17. Lowering district heating temperatures – Impact to system performance in current and future Danish energy scenarios

    DEFF Research Database (Denmark)

    Ommen, Torben; Markussen, Wiebke Brix; Elmegaard, Brian

    2016-01-01

    CHP (Combined heat and power) production in connection with DH (district heating) systems has previously demonstrated a significant reduction in primary energy consumption. With extended installation of intermittent sustainable sources, such as eg. wind turbines rather than thermal units, the cha......CHP (Combined heat and power) production in connection with DH (district heating) systems has previously demonstrated a significant reduction in primary energy consumption. With extended installation of intermittent sustainable sources, such as eg. wind turbines rather than thermal units...

  18. Flexibility of a combined heat and power system with thermal energy storage for district heating

    International Nuclear Information System (INIS)

    Nuytten, Thomas; Claessens, Bert; Paredis, Kristof; Van Bael, Johan; Six, Daan

    2013-01-01

    Highlights: ► A generic model for flexibility assessment of thermal systems is proposed. ► The model is applied to a combined heat and power system with thermal energy storage. ► A centrally located storage offers more flexibility compared to individual units. ► Increasing the flexibility requires both a more powerful CHP and a larger buffer. - Abstract: The trend towards an increased importance of distributed (renewable) energy resources characterized by intermittent operation redefines the energy landscape. The stochastic nature of the energy systems on the supply side requires increased flexibility at the demand side. We present a model that determines the theoretical maximum of flexibility of a combined heat and power system coupled to a thermal energy storage solution that can be either centralized or decentralized. Conventional central heating, to meet the heat demand at peak moments, is also available. The implications of both storage concepts are evaluated in a reference district. The amount of flexibility created in the district heating system is determined by the approach of the system through delayed or forced operation mode. It is found that the distinction between the implementation of the thermal energy storage as a central unit or as a collection of local units, has a dramatic effect on the amount of available flexibility

  19. Efficient district heating in the future energy system. Final report; Effektiv fjernvarme i fremtidens energisystem. Slutrapport

    Energy Technology Data Exchange (ETDEWEB)

    2009-07-01

    The purpose of this project is to illustrate how district heating can develop its role in the future Danish energy system, for example by reducing energy losses and the dynamic use of common technologies such as cogeneration and heat storage, and less widespread technologies such as heat pumps, geothermal heating, and cooling. The aim is also to analyse how electricity and district heating can interact more effectively, and to point out how framework conditions are important for district heating's continued development and efficiency. In the project, a linear optimization model is developed and applied as to analyse the interaction between district heating supply on the one hand, and energy savings, CO{sub 2} targets, wind power and the international electricity market on the other hand. Furthermore, more close-case operational analyses of district heating systems have been made in Ringkoebing and the metropolitan area, based on data from the district heating companies. Finally, a wide range of challenges for district heating in the long term were discussed and analysed during meetings with the project's reference group, including the need for development and demonstration projects. (ln)

  20. Down-Hole Heat Exchangers: Modelling of a Low-Enthalpy Geothermal System for District Heating

    Directory of Open Access Journals (Sweden)

    M. Carlini

    2012-01-01

    Full Text Available In order to face the growing energy demands, renewable energy sources can provide an alternative to fossil fuels. Thus, low-enthalpy geothermal plants may play a fundamental role in those areas—such as the Province of Viterbo—where shallow groundwater basins occur and conventional geothermal plants cannot be developed. This may lead to being fuelled by locally available sources. The aim of the present paper is to exploit the heat coming from a low-enthalpy geothermal system. The experimental plant consists in a down-hole heat exchanger for civil purposes and can supply thermal needs by district heating. An implementation in MATLAB environment is provided in order to develop a mathematical model. As a consequence, the amount of withdrawable heat can be successfully calculated.

  1. Environomic multi-objective optimisation of a district heating network considering centralized and decentralized heat pumps

    International Nuclear Information System (INIS)

    Molyneaux, A.; Leyland, G.; Favrat, D.

    2010-01-01

    Concern for the environment has been steadily growing in recent years, and it is becoming more common to include environmental impact and pollution costs in the design problem along with construction, investment and operating costs. To economically respond to the global environmental problems ahead, progress must be made both on more sustainable technologies and on the design methodology, which needs to adopt a more holistic approach. Heat pumps and, in particular systems integrating heat pumps and cogeneration units, offer a significant potential for greenhouse gas reduction. This paper illustrates the application of a multi-objective and multi-modal evolutionary algorithm to facilitate the design and planning of a district heating network based on a combination of centralized and decentralized heat pumps combined with on-site cogeneration. Comparisons are made with an earlier study based on a single objective environomic optimisation of the same overall model.

  2. The small-scale production of hydrogen, with the co-production of electricity and district heat, by means of the gasification of municipal solid waste

    International Nuclear Information System (INIS)

    Hognert, Johannes; Nilsson, Lars

    2016-01-01

    Highlights: • Outline of a process for handling municipal solid waste potentially leading to reduced use of fossil transportation fuels. • The integration of waste gasification into a district heat plant leads to excellent energy efficiency. • Analysis based on actual production data from a district heat plant over the period of one year. • Simulation of a plant with productions of heat, power and gaseous hydrogen. - Abstract: Reducing the use of fossil fuels and increasing the recycling of waste are two important challenges for a sustainable society. Fossil fuels contribute to global warming whilst waste causes the pollution of land, water and air. Alternative fuels and innovative waste management systems are needed to address these issues. In this study a gasification process, fuelled with municipal solid waste, was assumed to be integrated into a heat plant to produce hydrogen, electricity and district heat. A whole system, which includes a gasification reactor, heat plant, steam cycle, pressure swing adsorption, gas turbine and compressors was modelled in Microsoft Excel and an energy balance of the system was solved. Data from the scientific literature were used when setting up the heat and mass balances of the gasification process as well as for assessment of the composition of the syngas. The allocation of energy of the products obtained in the process is 29% hydrogen, 26% electricity and 45% district heat. A significant result of the study is the high energy efficiency (88%) during the cold period of the year when the produced heat in the system is utilized for district heat. The system also shows a competitive energy efficiency (56.5%) all year round.

  3. The effect of cooling conditions on convective heat transfer and flow in a steam-cooled ribbed duct

    International Nuclear Information System (INIS)

    Shui, Linqi; Gao, Jianmin; Shi, Xiaojun; Liu, Jiazeng; Xu, Liang

    2014-01-01

    This work presents a numerical and experimental investigation on the heat transfer and turbulent flow of cooling steam in a rectangular duct with 90 .deg. ribs and studies the effect of cooling conditions on the heat transfer augmentation of steam. In the calculation, the variation range of Reynolds is from 10,000 to 190,000, the inlet temperature varies from 300 .deg. C to 500 .deg. C and the outlet pressure is from 0.5MPa to 6MPa. The aforementioned wide ranges of flow parameters cover the actual operating condition of coolant used in the gas turbine blades. The computations are carried with four turbulence models (the standard k-ε, the renormalized group (RNG) k-ε, the Launder-Reece-Rodi (LRR) and the Speziale-Sarkar-Gatski (SSG) turbulence models). The comparison of numerical and experimental results reveals that the SSG turbulence model is suitable for steam flow in the ribbed duct. Therefore, adopting the conjugate calculation technique, further study on the steam heat transfer and flow characteristics is performed with SSG turbulence model. The results show that the variation of cooling condition strongly impacts the forced convection heat transfer of steam in the ribbed duct. The cooling supply condition of a relative low temperature and medium pressure could bring a considerable advantage on steam thermal enhancement. In addition, comparing the heat transfer level between steam flow and air flow, the performance advantage of using steam is also influenced by the cooling supply condition. Changing Reynolds number has little effect on the performance superiority of steam cooling. Increasing pressure would strengthen the advantage, but increasing temperature gives an opposite result.

  4. The effect of cooling conditions on convective heat transfer and flow in a steam-cooled ribbed duct

    Energy Technology Data Exchange (ETDEWEB)

    Shui, Linqi; Gao, Jianmin; Shi, Xiaojun; Liu, Jiazeng; Xu, Liang [Xi' an Jiaotong University, Xi' an (China)

    2014-01-15

    This work presents a numerical and experimental investigation on the heat transfer and turbulent flow of cooling steam in a rectangular duct with 90 .deg. ribs and studies the effect of cooling conditions on the heat transfer augmentation of steam. In the calculation, the variation range of Reynolds is from 10,000 to 190,000, the inlet temperature varies from 300 .deg. C to 500 .deg. C and the outlet pressure is from 0.5MPa to 6MPa. The aforementioned wide ranges of flow parameters cover the actual operating condition of coolant used in the gas turbine blades. The computations are carried with four turbulence models (the standard k-ε, the renormalized group (RNG) k-ε, the Launder-Reece-Rodi (LRR) and the Speziale-Sarkar-Gatski (SSG) turbulence models). The comparison of numerical and experimental results reveals that the SSG turbulence model is suitable for steam flow in the ribbed duct. Therefore, adopting the conjugate calculation technique, further study on the steam heat transfer and flow characteristics is performed with SSG turbulence model. The results show that the variation of cooling condition strongly impacts the forced convection heat transfer of steam in the ribbed duct. The cooling supply condition of a relative low temperature and medium pressure could bring a considerable advantage on steam thermal enhancement. In addition, comparing the heat transfer level between steam flow and air flow, the performance advantage of using steam is also influenced by the cooling supply condition. Changing Reynolds number has little effect on the performance superiority of steam cooling. Increasing pressure would strengthen the advantage, but increasing temperature gives an opposite result.

  5. Selection of values of design peak heat flux to reduce the risk of waterside corrosion in F.R. steam generators

    International Nuclear Information System (INIS)

    Bolt, P.R.; Garnsey, R.

    1975-01-01

    Attention is drawn to the high levels of peak heat Flux that can exist in sodium heated steam generators. The strength of the relationship between heat, flux and both deposition rate and the concentration of salts is discussed. Relevant steam generator operational experience obtained on the C.E.G.B. system is described and tentative proposals are made for limits to he to the peak heat flux values used in F.R. steam generator design. (author)

  6. Selection of values of design peak heat flux to reduce the risk of waterside corrosion in F.R. steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Bolt, P R; Garnsey, R

    1975-07-01

    Attention is drawn to the high levels of peak heat Flux that can exist in sodium heated steam generators. The strength of the relationship between heat, flux and both deposition rate and the concentration of salts is discussed. Relevant steam generator operational experience obtained on the C.E.G.B. system is described and tentative proposals are made for limits to he to the peak heat flux values used in F.R. steam generator design. (author)

  7. Design of an automatic control system of a district heating nuclear plant

    International Nuclear Information System (INIS)

    Zebiri, Abderrahim.

    1980-06-01

    This paper presents the synthesis of the control system of a nuclear/oil fuelled district heating plant. Operating criteria take into account the economical background of the problem. Nuclear reactor control loops were specially conceived, due to the specific perturbations to which is submitted a district heating plant [fr

  8. Performance of low-temperature district heating for low-energy houses

    DEFF Research Database (Denmark)

    Brand, Marek; Dalla Rosa, Alessandro; Svendsen, Svend

    2010-01-01

    A Low Energy District Heating (LEDH) network supplying district heating water with temperature 50°C was built in Lærkehaven-Lystrup, Denmark, as a part of the ongoing “Energy Technology Development and Demonstration Programme” [EUDP, 2008] focused on “CO2-reduction in low energy buildings and com...

  9. Innovation in the district heating. Process study in February 2012; Innovasjon i fjernvarme. Prossesstudie februar 201

    Energy Technology Data Exchange (ETDEWEB)

    Hoey, Mads Bruun

    2012-07-01

    This process study shows that, in order to create more innovation for growth in the district heating sector, it requires a new initiative, carried out by the district heating companies themselves, in the areas described in the study. This is regarded as the opportunities that the program should look for and will be more complete by the descriptions of the workshop results. (eb)

  10. Themoeconomic optimization of triple pressure heat recovery steam generator operating parameters for combined cycle plants

    Directory of Open Access Journals (Sweden)

    Mohammd Mohammed S.

    2015-01-01

    Full Text Available The aim of this work is to develop a method for optimization of operating parameters of a triple pressure heat recovery steam generator. Two types of optimization: (a thermodynamic and (b thermoeconomic were preformed. The purpose of the thermodynamic optimization is to maximize the efficiency of the plant. The selected objective for this purpose is minimization of the exergy destruction in the heat recovery steam generator (HRSG. The purpose of the thermoeconomic optimization is to decrease the production cost of electricity. Here, the total annual cost of HRSG, defined as a sum of annual values of the capital costs and the cost of the exergy destruction, is selected as the objective function. The optimal values of the most influencing variables are obtained by minimizing the objective function while satisfying a group of constraints. The optimization algorithm is developed and tested on a case of CCGT plant with complex configuration. Six operating parameters were subject of optimization: pressures and pinch point temperatures of every three (high, intermediate and low pressure steam stream in the HRSG. The influence of these variables on the objective function and production cost are investigated in detail. The differences between results of thermodynamic and the thermoeconomic optimization are discussed.

  11. District heating in Switzerland: Giving a survey and studying an example case

    Energy Technology Data Exchange (ETDEWEB)

    Kiss, M; Minder, R

    1981-05-01

    Today it is generally accepted that district-heating has essential adventages in areas which are suitable for it - as opposed to the heating mode which is most widely practiced in Switzerland, i.e. individual oil heating. These advantages shall only be pointed out briefly, here, by mentioning the following key words: economy, exploitation of fuel, safety of supply, and enviromental protection. Principally supporting the expansion of existing district-heating installations or the construction of new ones the authors give their view on the subject concerning the contribution to the total supply of heat which reasonably may be attributed to district-heating; they also give their opinion of the plans of a Swiss municipality as to its energy and district-heating supply.

  12. Numerical simulation of dryout and post-dryout heat transfer in a straight-pipe once-through steam generator

    International Nuclear Information System (INIS)

    Shi, Jianxin; Sun, Baozhi; Han, Wenjing; Zhang, Guolei; Li, Yanjun; Yang, Longbin

    2016-01-01

    Highlights: • Two-fluid three-flow-field model is developed to predict dryout in steam generator. • The empirical correlation is used to correct dryout criterion. • The interactions between three-flow-fields and the wall are considered. • Dryout and post-dryout heat transfer mechanisms are discussed through the results. - Abstract: Accurately predicting dryout and post-dryout heat transfer characteristics is critical for proper design of once-through steam generators. This paper provides a reasonable and simple method for this prediction by introducing a two-fluid, three-flow-field mathematical model and improving the dryout criterion-critical quality, and conducts a numerical simulation of dryout and post-dryout heat transfer in a once-through steam generator to prove the model’s performance. The results show that the critical quality in a once-through steam generator is about 0.82, with the heat transfer capacity significantly reducing and the wall temperature sharply increasing in a non-linear form by approximately 30 K when dryout occurs. Part of the steam is superheated in the post-dryout region, resulting in a deviation from thermodynamic equilibrium between the vapor and liquid phases. Dryout and post-dryout heat transfer in the once-through steam generator operate between complete deviation from thermodynamic equilibrium and complete thermodynamic equilibrium. Therefore, the presence of droplets has a significant influence on the mass, momentum and energy transfer between the film and vapor phases.

  13. Energy-Recovery Pressure-Reducer in District Heating System

    Directory of Open Access Journals (Sweden)

    Dariusz Borkowski

    2018-06-01

    Full Text Available Already existing man-made infrastructures that create water flow and unused pressure are interesting energy sources to which micro-hydropower plants can be applied. Apart from water supply systems (WSSs, which are widely described in the literature, significant hydropower potential can also be found in district heating systems (DHSs. In this paper, a prototype, a so-called energy-recovery pressure-reducer (ERPR, utilized for a DHS, is presented. It consisted of a pump as a turbine coupled to a permanent magnet synchronous generator (PMSG. The latter was connected to the power grid through the power electronic unit (PEU. The variable-speed operation allowed one to modify the turbine characteristics to match the substation’s hydraulic conditions. The proposed ERPR device could be installed in series to the existing classic pressure reducing valve (PRV as an independent device that reduces costs and simplifies system installation. The test results of the prototype system located in a substation of Cracow’s DHS are presented. The steady-state curves and regulation characteristics show the prototype’s operating range and efficiency. In this study, the pressure-reducer impact on the electrical and hydraulic systems, and on the environment, were analyzed. The operation tests during the annual heating season revealed an average system’s efficiency of 49%.

  14. Clustering-based analysis for residential district heating data

    DEFF Research Database (Denmark)

    Gianniou, Panagiota; Liu, Xiufeng; Heller, Alfred

    2018-01-01

    The wide use of smart meters enables collection of a large amount of fine-granular time series, which can be used to improve the understanding of consumption behavior and used for consumption optimization. This paper presents a clustering-based knowledge discovery in databases method to analyze r....... These findings will be valuable for district heating utilities and energy planners to optimize their operations, design demand-side management strategies, and develop targeting energy-efficiency programs or policies.......The wide use of smart meters enables collection of a large amount of fine-granular time series, which can be used to improve the understanding of consumption behavior and used for consumption optimization. This paper presents a clustering-based knowledge discovery in databases method to analyze...... residential heating consumption data and evaluate information included in national building databases. The proposed method uses the K-means algorithm to segment consumption groups based on consumption intensity and representative patterns and ranks the groups according to daily consumption. This paper also...

  15. Geothermal District Heating Institutional Factors: The Klamath Falls Experience

    Energy Technology Data Exchange (ETDEWEB)

    Lienau, Paul J

    1984-01-01

    The city of Klamath Falls Geothermal District Heating System started to provide heat to 10 government buildings on March 20, 1984. This startup was two and one-half years after construction of the system was completed and the operation is scheduled for only a four-month test period. The delay was the result of citizens objecting to pumping and injecting geothermal fluids in the reservoir and was legally enforced by means of a city ordinance passed by the voters. This Initiative Ordinance essentially regulates the resource by requiring any additional water pumped from a geothermal well be returned to that same well. The state of Oregon filed a lawsuit against the city, claiming that state regulation preempted city action. The issue currently is in the Court of Appeals, after Klamath County Circuit Court ruled that the state was not preempted and the ordinance was valid and enforceable. Historical description of development that led up to these institutional and legal problems are discussed. Citizens objections and third party mitigation measures by means of reservoir engineering studies and public meetings are described. Lessons learned from the Klamath Falls experience are pointed out so future developments in other communities may benefit.

  16. Condensation heat transfer coefficient in horizontal stratified cocurrent flow of steam and cold water

    International Nuclear Information System (INIS)

    Kim, Kap; Kim, Hho Jung

    1986-01-01

    Some studies on direct-contact condensation in cocurrent stratified flow of steam and subcooled water were reviewed. Several approaches have been performed to develop the condensation heat transfer coefficient relationship. The local Nusselt number is correlated in terms of the local water Reynolds and Prandtl numbers as well as the steam Froude number. In addition, a turbulence-centered model, developed principally for gas absorption in several geometries, is modified by using calculated interfacial parameters for the turbulent velocity and length scales. These approaches result in a fairly good agreement with the data, whereas, the turbulence-centered model is here recommended since it is based on the turbulent properties which may be closely related to the condensation phenomena. (Author)

  17. CO2 emissions and heat flow through soil, fumaroles, and steam heated mud pools at the Reykjanes geothermal area, SW Iceland

    International Nuclear Information System (INIS)

    Fridriksson, Thrainn; Kristjansson, Bjarni Reyr; Armannsson, Halldor; Margretardottir, Eygerour; Olafsdottir, Snjolaug; Chiodini, Giovanni

    2006-01-01

    Carbon dioxide emissions and heat flow through soil, steam vents and fractures, and steam heated mud pools were determined in the Reykjanes geothermal area, SW Iceland. Soil diffuse degassing of CO 2 was quantified by soil flux measurements on a 600 m by 375 m rectangular grid using a portable closed chamber soil flux meter and the resulting data were analyzed by both a graphical statistical method and sequential Gaussian simulations. The soil temperature was measured in each node of the grid and used to evaluate the heat flow. The heat flow data were also analyzed by sequential Gaussian simulations. Heat flow from steam vents and fractures was determined by quantifying the amount of steam emitted from the vents by direct measurements of steam flow rate. The heat loss from the steam heated mud pools was determined by quantifying the rate of heat loss from the pools by evaporation, convection, and radiation. The steam flow rate into the pools was calculated from the observed heat loss from the pools, assuming that steam flow was the only mechanism of heat transport into the pool. The CO 2 emissions from the steam vents and mud pools were determined by multiplying the steam flow rate from the respective sources by the representative CO 2 concentration of steam in the Reykjanes area. The observed rates of CO 2 emissions through soil, steam vents, and steam heated mud pools amounted to 13.5 ± 1.7, 0.23 ± 0.05, and 0.13 ± 0.03 tons per day, respectively. The heat flow through soil, steam vents, and mud pools was 16.9 ± 1.4, 2.2 ± 0.4, and 1.2 ± 0.1 MW, respectively. Heat loss from the geothermal reservoir, inferred from the CO 2 emissions through the soil amounts to 130 ± 16 MW of thermal energy. The discrepancy between the observed heat loss and the heat loss inferred from the CO 2 emissions is attributed to steam condensation in the subsurface due to interactions with cold ground water. These results demonstrate that soil diffuse degassing can be a more

  18. Feasibility and Supply Analysis of U.S. Geothermal District Heating and Cooling System

    Science.gov (United States)

    He, Xiaoning

    Geothermal energy is a globally distributed sustainable energy with the advantages of a stable base load energy production with a high capacity factor and zero SOx, CO, and particulates emissions. It can provide a potential solution to the depletion of fossil fuels and air pollution problems. The geothermal district heating and cooling system is one of the most common applications of geothermal energy, and consists of geothermal wells to provide hot water from a fractured geothermal reservoir, a surface energy distribution system for hot water transmission, and heating/cooling facilities to provide water and space heating as well as air conditioning for residential and commercial buildings. To gain wider recognition for the geothermal district heating and cooling (GDHC) system, the potential to develop such a system was evaluated in the western United States, and in the state of West Virginia. The geothermal resources were categorized into identified hydrothermal resources, undiscovered hydrothermal resources, near hydrothermal enhanced geothermal system (EGS), and deep EGS. Reservoir characteristics of the first three categories were estimated individually, and their thermal potential calculated. A cost model for such a system was developed for technical performance and economic analysis at each geothermally active location. A supply curve for the system was then developed, establishing the quantity and the cost of potential geothermal energy which can be used for the GDHC system. A West Virginia University (WVU) case study was performed to compare the competiveness of a geothermal energy system to the current steam based system. An Aspen Plus model was created to simulate the year-round campus heating and cooling scenario. Five cases of varying water flow rates and temperatures were simulated to find the lowest levelized cost of heat (LCOH) for the WVU case study. The model was then used to derive a levelized cost of heat as a function of the population density

  19. Exergy analysis and evolutionary optimization of boiler blowdown heat recovery in steam power plants

    International Nuclear Information System (INIS)

    Vandani, Amin Mohammadi Khoshkar; Bidi, Mokhtar; Ahmadi, Fatemeh

    2015-01-01

    Highlights: • Heat recovery of boiler blow downed water using a flash tank is modeled. • Exergy destruction of each component is calculated. • Exergy efficiency of the whole system is optimized using GA and PSO algorithms. • Utilizing the flash tank increases the net power and efficiency of the system. - Abstract: In this study, energy and exergy analyses of boiler blowdown heat recovery are performed. To evaluate the effect of heat recovery on the system performance, a steam power plant in Iran is selected and the results of implementation of heat recovery system on the power plant are investigated. Also two different optimization algorithms including GA and PSO are established to increase the plant efficiency. The decision variables are extraction pressure from steam turbine and temperature and pressure of boiler outlet stream. The results indicate that using blowdown recovery technique, the net generated power increases 0.72%. Also energy and exergy efficiency of the system increase by 0.23 and 0.22, respectively. The optimization results show that temperature and pressure of boiler outlet stream have a higher effect on the exergy efficiency of the system in respect to the other decision variables. Using optimization methods, exergy efficiency of the system reaches to 30.66% which shows a 1.86% augmentation with regard to the situation when a flash tank is implemented.

  20. Heat transfer and friction characteristics in steam cooled rectangular channels with rib turbulators

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Jianying; Gao, Tieyu; Li, Guojun [Xi' an Jiaotong University, Xi' an (China)

    2014-01-15

    We studied the heat transfer and friction characteristics in steam-cooled rectangular channels with rib turbulators on W side or H side walls in the Reynolds number (Re) range of 10000-80000. Each of the test channels was welded by four stainless steel plates to simulate the actual geometry and heat transfer structure of blade/vane internal cooling passage. The length of the channel L was 1000 mm, the cross section of the channel was 40 mm X 80 mm, and the pitch-to-rib height ratio p/e was kept at 10. The channel blockage ratio (W/H) was 0.047. Results showed that the Nusselt number (Nu) distributions displayed different trends at the entrance region with the increase of Re for the rib turbulators on the W side walls. The heat transfer performance of the rib turbulators on the H side walls was about 24- 27% higher than that on the W side walls at the same pumping power. In addition, semi-empirical correlations for the two cases, rib turbulators on W side walls and rib turbulators on H side walls, were developed based on the heat transfer results, which could be used in the design of the internal cooling passage of new generation steam-cooled gas turbine blade/vane.

  1. The Innovative Concept of Cold District Heating Networks: A Literature Review

    Directory of Open Access Journals (Sweden)

    Marco Pellegrini

    2018-01-01

    Full Text Available The development of sustainable and innovative solutions for the production and supply of energy at district level is nowadays one of the main technical challenges. In the past, district heating and cooling networks aimed to achieve greater energy efficiency through the centralization of the energy production process but with relevant losses related to heat transport. Moving towards a higher share of renewables and lower demand of primary energy requires redesign of the energy district networks. The novel concept of cold district heating networks aims to combine the advantages of a centralized energy distribution system with low heat losses in energy supply. This combined effect is achieved through the centralized supply of water at relatively low temperatures (in the range 10–25 °C, which is then heated up by decentralized heat pumps. Moreover, cold district heating networks are also very suitable for cooling delivery, since cold water supplying can be directly used for cooling purposes (i.e., free cooling or to feed decentralized chillers with very high energy efficiency ratio. This paper provides a preliminary literature review of existing cold district heating networks and then qualitatively analyses benefits and drawbacks in comparison with the alternatives currently used to produce heat and cold at district level, including the evaluation of major barriers to its further development.

  2. Development of Technologies on Innovative-Simplified Nuclear Power Plant Using High-Efficiency Steam Injectors (12) Evaluations of Spatial Distributions of Flow and Heat Transfer in Steam Injector

    International Nuclear Information System (INIS)

    Yutaka Abe; Yujiro Kawamoto; Chikako Iwaki; Tadashi Narabayashi; Michitsugu Mori; Shuichi Ohmori

    2006-01-01

    Next-generation nuclear reactor systems have been under development aiming at simplified system and improvement of safety and credibility. One of the innovative technologies is the supersonic steam injector, which has been investigated as one of the most important component of the next-generation nuclear reactor. The steam injector has functions of a passive pump without large motor or turbo-machinery and a high efficiency heat exchanger. The performances of the supersonic steam injector as a pump and a heat exchanger are dependent on direct contact condensation phenomena between a supersonic steam and a sub-cooled water jet. In previous studies of the steam injector, there are studies about the operating characteristics of steam injector and about the direct contact condensation between static water pool and steam in atmosphere. However, there is a little study about the turbulent heat transfer and flow behavior under the great shear stress. In order to examine the heat transfer and flow behavior in supersonic steam injector, it is necessary to measure the spatial temperature distribution and velocity in detail. The present study, visible transparent supersonic steam injector is used to obtain the axial pressure distributions in the supersonic steam injector, as well as high speed visual observation of water jet and steam interface. The experiments are conducted with and without non-condensable gas. The experimental results of the interfacial flow behavior between steam and water jet are obtained. It is experimentally clarified that an entrainment exists on the water jet surface. It is also clarified that discharge pressure is depended on the steam supply pressure, the inlet water flow rate, the throat diameter and non-condensable flow rate. Finally a heat flux is estimated about 19 MW/m 2 without non-condensable gas condition in steam. (authors)

  3. Large scale solar district heating. Evaluation, modelling and designing

    Energy Technology Data Exchange (ETDEWEB)

    Heller, A.

    2000-07-01

    The main objective of the research was to evaluate large-scale solar heating connected to district heating (CSDHP), to build up a simulation tool and to demonstrate the application of the tool for design studies and on a local energy planning case. The evaluation of the central solar heating technology is based on measurements on the case plant in Marstal, Denmark, and on published and unpublished data for other, mainly Danish, CSDHP plants. Evaluations on the thermal, economical and environmental performances are reported, based on the experiences from the last decade. The measurements from the Marstal case are analysed, experiences extracted and minor improvements to the plant design proposed. For the detailed designing and energy planning of CSDHPs, a computer simulation model is developed and validated on the measurements from the Marstal case. The final model is then generalised to a 'generic' model for CSDHPs in general. The meteorological reference data, Danish Reference Year, is applied to find the mean performance for the plant designs. To find the expectable variety of the thermal performance of such plants, a method is proposed where data from a year with poor solar irradiation and a year with strong solar irradiation are applied. Equipped with a simulation tool design studies are carried out spreading from parameter analysis over energy planning for a new settlement to a proposal for the combination of plane solar collectors with high performance solar collectors, exemplified by a trough solar collector. The methodology of utilising computer simulation proved to be a cheap and relevant tool in the design of future solar heating plants. The thesis also exposed the demand for developing computer models for the more advanced solar collector designs and especially for the control operation of CSHPs. In the final chapter the CSHP technology is put into perspective with respect to other possible technologies to find the relevance of the application

  4. Road map for district heating. The role of district heating in the energy system. Main report; Denmark; Roadmap for fjernvarmen. Fjernvarmens rolle i energisystemet. Hovedrapport

    Energy Technology Data Exchange (ETDEWEB)

    Hofmeister, M.; Aabye Moeller, A.; Eggert, A.; Bjerregaard, M. (Fjernvarmens Udviklingscenter, AArhus (Denmark)); Dyrelund, A. (Ramboell, Koebenhavn (Denmark)); OErsted Pedersen, H. (Ea Energianalyse, Koebenhavn (Denmark)); Lund, H. (Aalborg Univ., Aalborg (Denmark))

    2011-07-01

    In the recent years many studies of how Denmark can be fossil free by 2050 it is agreed that district heating will play a crucial role. District heating is an important factor of phasing out fossil fuels in an energy-and cost-effective way. But the future energy supply without fossil fuels poses new requirements for district heating. In the future, district heating shall provide energy for low-energy houses, have low distribution losses and use a variety of heat sources such as geothermal, solar, waste, surplus heat, CHP and various biomass con-version processes. In addition, it must all be done in an energy efficient way and in an active interaction with production of electricity and electricity consumption and, through integration of electricity from wind, solar and wave power. Low temperature, use of heat pumps and the interaction with electricity and biomass will be keywords. It is not only in Denmark we will need an active development of future technologies and systems. Large parts of Europe and many other parts of the world need the same development, and today Denmark has a significant export in the market - an export that has risen sharply, despite the recent economic recession. There is thus a double need to actively promote the development of future district heating technologies. We will partly need the technology development to realize the goal of a fossil free society and secondly because it is necessary to maintain and expand the export. This report contains a number of proposals for concrete actions - a roadmap for the development of district heating. The project is anchored at the District Energy Development Center that will work for an implementation of the concrete project ideas after the project completion. There is a need to increase the activity level for development of district heating. There is therefore a need to ensure financing of this development. We suggest that this can be done by creating an opportunity for a more sustained funding, for

  5. Road map for district heating. The role of district heating in the energy system. Summary report; Denmark; Roadmap for fjernvarmen. Fjernvarmens rolle i energisystemet. Resumerapport

    Energy Technology Data Exchange (ETDEWEB)

    Hofmeister, M.; Aabye Moeller, A.; Eggert, A.; Bjerregaard, M. (Fjernvarmens Udviklingscenter, AArhus (Denmark)); Dyrelund, A. (Ramboell, Koebenhavn (Denmark)); OErsted Pedersen, H. (Ea Energianalyse, Koebenhavn (Denmark)); Lund, H. (Aalborg Univ., Aalborg (Denmark))

    2011-07-01

    In the recent years many studies of how Denmark can be fossil free by 2050 it is agreed that district heating will play a crucial role. District heating is an important factor of phasing out fossil fuels in an energy-and cost-effective way. But the future energy supply without fossil fuels poses new requirements for district heating. In the future, district heating shall provide energy for low-energy houses, have low distribution losses and use a variety of heat sources such as geothermal, solar, waste, surplus heat, CHP and various biomass con-version processes. In addition, it must all be done in an energy efficient way and in an active interaction with production of electricity and electricity consumption and, through integration of electricity from wind, solar and wave power. Low temperature, use of heat pumps and the interaction with electricity and biomass will be keywords. It is not only in Denmark we will need an active development of future technologies and systems. Large parts of Europe and many other parts of the world need the same development, and today Denmark has a significant export in the market - an export that has risen sharply, despite the recent economic recession. There is thus a double need to actively promote the development of future district heating technologies. We will partly need the technology development to realize the goal of a fossil free society and secondly because it is necessary to maintain and expand the export. This report contains a number of proposals for concrete actions - a roadmap for the development of district heating. The project is anchored at the District Energy Development Center that will work for an implementation of the concrete project ideas after the project completion. There is a need to increase the activity level for development of district heating. There is therefore a need to ensure financing of this development. We suggest that this can be done by creating an opportunity for a more sustained funding, for

  6. Use of reactor plants of enhanced safety for sea water desalination, industrial and district heating

    International Nuclear Information System (INIS)

    Panov, Yu.; Polunichev, V.; Zverev, K.

    1997-01-01

    Russian designers have developed and can deliver nuclear complexes to provide sea water desalination, industrial and district heating. This paper provides an overview of these designs utilizing the ABV, KLT-40 and ATETS-80 reactor plants of enhanced safety. The most advanced nuclear powered water desalination project is the APVS-80. This design consists of a special ship equipped with the distillation desalination plant powered at a level of 160 MW(th) utilizing the type KLT-40 reactor plant. More than 20 years of experience with water desalination and reactor plants has been achieved in Aktau and Russian nuclear ships without radioactive contamination of desalinated water. Design is also proceeding on a two structure complex consisting of a floating nuclear power station and a reverse osmosis desalination plant. This new technology for sea water desalination provides the opportunity to considerably reduce the specific consumption of power for the desalination of sea water. The ABV reactor is utilized in the ''Volnolom'' type floating nuclear power stations. This design also features a desalinator ship which provides sea water desalination by the reverse osmosis process. The ATETS-80 is a nuclear two-reactor cogeneration complex which incorporates the integral vessel-type PWR which can be used in the production of electricity, steam, hot and desalinated water. (author). 9 figs

  7. Status of steam gasification of coal by using heat from high-temperature reactors (HTRs)

    International Nuclear Information System (INIS)

    Schroeter, H.J.; Kirchhoff, R.; Heek, K.H. van; Juentgen, H.; Peters, W.

    1984-01-01

    Bergbau-Forschung GmbH, Essen, is developing a process for steam gasification of coal by using process heat from high-temperature nuclear reactors (HTRs). The envisaged allothermal gas generator is heated by an internally mounted bundle of heat exchanging tubes through which the gaseous reactor coolant helium flows. Research and development work for this process has been under way for about 11 years. After intensive small-scale investigations the principle of the process was tested in a semi-technical plant with 0.2 t/h coal throughput. In its gasifier a fluidized bed of approximately 1 m 2 cross-section and up to 4 m high is operated at 40 bar. Heat is supplied to the bed from an immersed heat exchanger with helium flowing through it. The gas generator is a cut-out version of the full-scale generator, in which the height of the bed, and the arrangement of the heat-exchanger tubes correspond to the full-scale design. The semi-technical plant has now achieved a total gasification time of about 13,000 hours. Roughly 2000 t of coal have been put through. During recent years the gasification of Federal German coking coal by using a jet-feeding system was demonstrated successfully. The results, confirmed and expanded by material tests for the heat exchanger, engineering and computer models and design studies, have shown the feasibility of nuclear steam gasification of coal. The process described offers the following advantages compared with existing processes: higher efficiency as more gas can be produced from less coal; less emission of pollutants as, instead of a coal-fired boiler, the HTR is used for producing steam and electricity; lower production costs for gas. The next step in the project is a pilot plant of about 2-4 t/h coal throughput, still with non-nuclear heating, to demonstrate the construction and operation of the allothermal gas generator on a representative scale for commercial applications. (author)

  8. Opening of the markets increases the risks of district heating business

    International Nuclear Information System (INIS)

    Silvennoinen, A.

    2001-01-01

    Maintenance of the technical operation conditions of district heating is the main requirement of community to the district heating business. Infrastructure of district heating, including the heat generation and distribution plants, equipment and devices, requires relatively large investments. Total process from fuel purchase to heat delivery does not occur in a closed limited area, but it penetrates the total market area (heat distribution network) and even larger via fuel purchase and transport. E.g. the fuels are combustible and might explode. Oil-spills into the environment may have catastrophic effects. Large leakage of hot district heating water is both environmentally hazardous and forms also a health hazard, and they stop the delivery of district heat. Dominant position on the markets is also followed closely by the authorities. On the other hand competition with other heating forms require efficient operation. The author reviews in the article the basics of risk management, and especially in the district heating business. The risk management process is discussed in the risk analysis and determination of the significance of the risks, the effects of realization of the risks, planning of the measures to be taken to avoid risks, and preparations against the risks

  9. Istra district heating system. Master plan and feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-09-01

    This report presents the results of the Feasibility Study of options for improving the efficiency and operating economy of Istra Large-Scale Demonstration Project includes all areas of the town of Istra. However, the Feasibility Study is confined to the five largest adjoining boilers plant areas within the borders of Istra town. The study was conducted from 1999 to 2001 and was based on information collected during this period. The city administration and the district heating company in Istra provided the data. The company RDIEE, Russian Danish Institute for Energy Efficiency, in Istra collected and processed the data under the conduction of Carl Bro a/s in Denmark. The main objectives of the study are to provide the Istra DHC with a number of options for future development of the district heating system based on technical/financial analyses and presenting the best possibilities for improved comfort, operation and business development. More concretely, one or more system improvement scenarios, which can be implemented in the near future as a first step of the recommended medium-term to long-term development, are identified. Another important objective has been to train the specialists of RDIEE in the feasibility study process and to transfer know-how, skills and tools. The model used for this study is adapted to the features and the special problems to be addressed in relation to the Istra district heating system. RDIEE and Istra DHC are thereby provided with a useful tool which may be used for continued study and development after the first phase project has been completed. As usual in the case of input/output models the quality of the results depends very much on the quality of input data. The present report is exclusively based on the consultant's understanding of the provided information. The results and the underlying inputs should be carefully considered before any final decision concerning implementation is taken. Verification of assumptions should also

  10. Equipment for secondary water distribution in heat exchanger, especially saturated steam generator for nuclear power plants and heat plants

    Energy Technology Data Exchange (ETDEWEB)

    Riman, J; Manek, O; Rybnicek, J

    1979-09-15

    A special structure consisting of a system of channels and a distribution plate with ports in-built above the tube-plate of a vertical-type steam generator prevents secondary water vaporization in the space above the tube-plate and thus also salt and sludge sedimentation which causes increased corrosion of heat transfer tubes. The size of the distribution plate ports is variable in the radial direction. The distribution plate is divided by means of the system of channels into at least two parts. The middle section of each part is of the through-flow type.

  11. Towards a Future of District Heating Systems with Low-Temperature Operation together with Non-Fossil Fuel Heat Sources

    DEFF Research Database (Denmark)

    Tol, Hakan; Dinçer, Ibrahim; Svendsen, Svend

    2012-01-01

    This study focused on investigation of non-fossil fuel heat sources to be supplied to low-energy district heating systems operating in low temperature such as 55 C and 25 C in terms of, respectively, supply and return. Vast variety of heat sources classed in categories such as fossil fuel...

  12. Heat balance calculation and feasibility analysis for initial startup of Fuqing nuclear turbine unit with non-nuclear steam

    International Nuclear Information System (INIS)

    He Liu; Xiao Bo; Song Yumeng

    2014-01-01

    Non-nuclear steam run up compared with nuclear steam run up, can verify the design, manufacture, installation quality of the unit, at the same time shorten the follow-up duration of the entire group ready to start debugging time. In this paper, starting from the first law of thermodynamics, Analyzed Heat balance Calculation and Feasibility analysis for Initial startup of Fuqing nuclear Turbine unit with Non-nuclear steam, By the above calculation, to the system requirements and device status on the basis of technical specifications, confirmed the feasibility of Non-nuclear steam running up in theory. After the implementation of the Non-nuclear turn of Fuqing unit, confirmed the results fit with the actual process. In summary, the Initial startup of Fuqing turbine unit with Non-nuclear steam is feasible. (authors)

  13. An equivalent marginal cost-pricing model for the district heating market

    International Nuclear Information System (INIS)

    Zhang, Junli; Ge, Bin; Xu, Hongsheng

    2013-01-01

    District heating pricing is a core element in reforming the heating market. Existing district heating pricing methods, such as the cost-plus pricing method and the conventional marginal-cost pricing method, cannot simultaneously provide both high efficiency and sufficient investment cost return. To solve this problem, the paper presents a new pricing model, namely Equivalent Marginal Cost Pricing (EMCP) model, which is based on the EVE pricing theory and the unique characteristics of heat products and district heating. The EMCP model uses exergy as the measurement of heating product value and places products from different district heating regions into the same competition platform. In the proposed model, the return on investment cost is closely related to the quoted cost, and within the limitations of the Heating Capacity Cost Reference and the maximum compensated shadow capacity cost, both lower and higher price speculations of heat producers are restricted. Simulation results show that the model can guide heat producers to bid according to their production costs and to provide reasonable returns on investment, which contributes to stimulate the role of price leverage and to promote the optimal allocation of heat resources. - Highlights: • Presents a new district heating pricing model. • Provides both high market efficiency and sufficient investment cost return. • Provides a competition mechanism for various products from different DH regions. • Both of lower and higher price speculations are restricted in the new model

  14. Casing of preinsulated district heating pipes. Functional Requirements. Scientific report

    Energy Technology Data Exchange (ETDEWEB)

    Bryder, K.L.; Feld, T.; Randloev, P.; Vestergaard, J.B.; Noergaard Pedersen, H.; Palle, S.; Amby, L.

    1996-10-01

    Requirements for the wall thickness of the casing pipes in Europe were formulated to clarify the laying conditions, representative for the European district heating areas. We achieved a broad estimate by defining four scenarios for the laying of district heating pipes. It is common to the four scenarios that that all bends, branches etc. are always laid in sand. The four scenarios are differentiated by soil types. The soil types include: Uniform sand, Well graded gravel, Sand with fines and Sand with crushed stone. In the following analysis it was possible to examine the influence from following parameters: Casing thickness; Diameter of steel pipe; Diameter of casing; Material properties (PUR and PE); Soil type. The results from the model showed that uniform sand is the absolute best soil type. Based on the results from and earlier project a laboratory method has been developed. The result was a test method based on the indentation of three mandrels with a diameter of {phi}30 mm with a taper with an angle of 45 deg. and with roundings on the apex of R5 mm, R10 mm and R15 mm, respectively. The mandrels simulate stones. The examinations among other things showed that even a 1.5 mm casing demands an indentation of 20 mm with a R5 mm mandrel before it is perforated. The demanded force is 1.6 kN, which is considerably higher than the theoretically highest force in an actual situation. On this background it is recommended that the minimum requirement for the wall thickness of the casings with diameters less than 200 mm should still follow the EN 253, whereas the minimum requirement for the larger casing pipes securely can be reduced. Based on the tests and an evaluation of the safety factors it is proposed that the wall thickness for the largest pipes can be reduced 50%. Thus the wall thickness of an 800 mm casing should be 6.6 mm with a linear reduction down to 3 mm for 180 mm casing. (EG)

  15. Casing of preinsulated district heating pipes. Functional Requirements. Enclosures

    Energy Technology Data Exchange (ETDEWEB)

    Bryder, K.L.; Feld, T.; Randloev, P.; Vestergaard, J.B.; Noergaard Pedersen, H.; Palle, S.; Amby, L.

    1996-10-01

    Requirements for the wall thickness of the casing pipes in Europe were formulated. In order to clarify the laying conditions, representative for the European district heating areas. It was possible to achieve a sufficiently broad estimate by defining four scenarios for the laying of district heating pipes. It is common to the four scenarios that that all bends, branches etc. are always laid in sand. The four scenarios are differentiated by soil types. The soil types include: Uniform sand, Well graded gravel, Sand with fines and Sand with crushed stone. In the following analysis it was possible to examine the influence from following parameters: Casing thickness; Diameter of steel pipe; Diameter of casing; Material properties (PUR and PE); Soil type. The results from the model showed that uniform sand is the absolute best soil type. Based on the results from and earlier project a laboratory method has been developed. The result was a test method based on the indentation of three mandrels with a diameter of {phi}30 mm with a taper with an angle of 45 deg. and with roundings on the apex of R5 mm, R10 mm and R15 mm, respectively. The mandrels simulate stones. The examinations among other things showed that even a 1.5 mm casing demands an indentation of 20 mm with a R5 mm mandrel before it is perforated. The demanded force is 1.6 kN, which is considerably higher than the theoretically highest force in an actual situation. On this background it is recommended that the minimum requirement for the wall thickness of the casings with diameters less than 200 mm should still follow the EN 253, whereas the minimum requirement for the larger casing pipes securely can be reduced. Based on the tests and an evaluation of the safety factors it is proposed that the wall thickness for the largest pipes can be reduced 50%. Thus the wall thickness of an 800 mm casing should be 6.6 mm with a linear reduction down to 3 mm for 180 mm casing. (EG)

  16. Heat treatment of large-sized welded rotors of steam turbines for atomic power stations

    Energy Technology Data Exchange (ETDEWEB)

    Kutasov, R F; Mukhina, M P; Tustanovskii, A S

    1977-01-01

    The heat treatment of a welded rotor of grade 25Kh2NMFA steel for steam turbines of nuclear power plants was considered. A following heat treatment schedule was suggested: charging the rotor in to a furnace at 100-150 deg C, heating to 200-250 deg C and holding for 12 hrs; slow heating (10 deg C/h) to 400-450 deg C and holding for 12 hrs; slow heating to 630-640 deg C and holding for 50 hrs, cooling at a rate of 5 deg C/h down to 100 deg C, holding for 20 hrs and cooling with the furnace open. The proposed heat treatment schedule of a duration of 356 hrs ensures a temperature gradient throughout the cross section and the length of the rotor of not more than +-5 deg C, least deviations of geometric dimensions and makes possible machining finish to within 0-0.02 mm. Described are the particularities of the design of a roll-out hearth electric chamber furnace, measuring 13000x5500x5000 mm and built for the purpose of carrying out said heat treatment. The power rating of the furnace is 2850 kW.

  17. Influence of different technologies on dynamic pricing in district heating systems: Comparative case studies

    DEFF Research Database (Denmark)

    Dominkovic, Dominik Franjo; Wahlroos, Mikko; Syri, Sanna

    2018-01-01

    District heating markets are often dominated by monopolies in both Denmark and Finland. The same companies, often owned by local municipalities, are usually operating both supplying plants and district heating networks, while the pricing mechanisms are rigid, often agreed upon for one year...... in advance. The mentioned ownership scheme may cause problems, when one tries to gain a third party access in order to deliver excess heat or heat from cheaper heating plants. In this paper, two case studies were carried out to simulate the district heating systems based on dynamic pricing. Case studies were...... carried out for Sønderborg, Denmark and Espoo, Finland. The results showed that dynamic pricing fosters feeding the waste heat into the grid, as dynamic pricing reduced the total primary energy consumption and CO2 emissions in both case studies. In the best scenarios, the weighted average heat price...

  18. Subchannel analysis and correlation of the Rod Bundle Heat Transfer (RBHT) steam cooling experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Riley, M.P.; Mohanta, L.; Miller, D.J.; Cheung, F.B. [Pennsylvania State Univ., University Park, PA (United States); Bajorek, S.M.; Tien, K.; Hoxie, C.L. [U.S. Nuclear Regulatory Commission, Washington, DC (United States). Office of Nuclear Regulatory Research

    2016-07-15

    A subchannel analysis of the steam cooling data obtained in the Rod Bundle Heat Transfer (RBHT) test facility has been performed in this study to capture the effect of spacer grids on heat transfer. The RBHT test facility has a 7 x 7 rod bundle with heater rods and with seven spacer grids equally spaced along the length of the rods. A method based on the concept of momentum and heat transport analogy has been developed for calculating the subchannel bulk mean temperature from the measured steam temperatures. Over the range of inlet Reynolds number, the local Nusselt number was found to exhibit a minimum value between the upstream and downstream spacer grids. The presence of a spacer grid not only affects the local Nusselt number downstream of the grid but also affects the local Nusselt number upstream of the next grid. A new correlation capturing the effect of Reynolds number on the local flow restructuring downstream as well as upstream of the spacer grids was proposed for the minimum Nusselt number. In addition, a new enhancement factor accounting for the effects of the upstream as well as downstream spacer grids was developed from the RBHT data. The new enhancement factor was found to compare well with the data from the ACHILLLES test facility.

  19. Temperature condition in decreasing heat transfer zone for NPP steam generators

    International Nuclear Information System (INIS)

    Kudryavtsev, I.S.; Paskar', B.L.; Sudakov, A.V.

    1985-01-01

    An experimental set-up is described and the results of temperature pulsation investigation are presented for coil steam generating channel surfaces of the NPP helium and sodium cooled HTGR. The investigations are carried out at the heat flux density of 350-900 kW/m 3 , the mass rate of 350-2000 kg/(m 2 Xs), the pressUre of 15 MPa. Temperature pulsations occur due to instability of heat transfer in the near-wall region. The results show that the critical region of burnout has a local character. Pulsation dependences on operating conditions are given. The required resource for the steam generating channel may be provided by chosing the ratio of heat flux to the mass rate, the ratio being equal to 0.5 kJ/kg for the channel with the internal diameter of 19 mm, made of the 12Kh2M steel, the wall thickness of 3 mm. In this case the maximum span of temperature pulsations doesn't exceed 25-30 K

  20. Steam turbine cycle

    International Nuclear Information System (INIS)

    Okuzumi, Naoaki.

    1994-01-01

    In a steam turbine cycle, steams exhausted from the turbine are extracted, and they are connected to a steam sucking pipe of a steam injector, and a discharge pipe of the steam injector is connected to an inlet of a water turbine. High pressure discharge water is obtained from low pressure steams by utilizing a pressurizing performance of the steam injector and the water turbine is rotated by the high pressure water to generate electric power. This recover and reutilize discharged heat of the steam turbine effectively, thereby enabling to improve heat efficiency of the steam turbine cycle. (T.M.)

  1. Feasibility Study for the Ivano-Frankivsk District Heating Repowering: Analysis of Options

    Energy Technology Data Exchange (ETDEWEB)

    Markel, L.; Popelka, A.; Laskarevsky, V.

    2002-03-20

    Part of the U.S. Initiative on Joint Implementation with the Ukraine Inter-Ministerial Commission on Climate Change, financed by the US Department of Energy. The project was implemented by a team consisting of the US company SenTech, Inc. and the Ukrainian company Esco-West. The main objective of the effort was to assess available alternatives of Ivano-Frankivsk (I-F) District Heating repowering and provide information for I-F's investment decision process. This study provides information on positive and negative technical and economic aspects of available options. Three options were analyzed for technical merit and economic performance: 1. Installation of cogeneration system based on Gas Turbine (GT) and Heat Recovery Heat Exchanger with thermal capacity of 30 MW and electrical capacity of 13.5 MW. This Option assumes utilization of five existing boilers with total capacity of 221 MW. Existing boilers will be equipped with modern controls. Equipment in this Option was sized for longest operating hours, about 8000 based on the available summer baseload. 2. Installation of Gas Turbine Combined Cycle (GTCC) and Heat Recovery Steam Generator (HRSG) with thermal capacity 45 MW and electrical capacity of 58.7 MW. This Option assumes utilization of five existing boilers with total capacity of 221 MW. Existing boilers will be equipped with modern controls. The equipment was sized for medium, shoulder season thermal load, and some cooling was assumed during the summer operation for extension of operating hours for electricity production. 3. Retrofit of six existing boilers (NGB) with total thermal capacity of 255.9 MW by installation of modern control system and minor upgrades. This option assumes only heat production with minimum investment. The best economic performance and the largest investment cost would result from alternative GTCC. This alternative has positive Net Present Value (NPV) with discount rate lower than about 12%, and has IRR slightly above 12%. The

  2. A numerical analysis of heat and mass transfer during the steam reforming process of ethane

    Science.gov (United States)

    Tomiczek, Marcin; Kaczmarczyk, Robert; Mozdzierz, Marcin; Brus, Grzegorz

    2017-11-01

    This paper presents a numerical analysis of heat and mass transfer during the steam reforming of ethane. From a chemical point of view, the reforming process of heavy hydrocarbons, such as ethane, is complex. One of the main issue is a set of undesired chemical reactions that causes the deposition of solid carbon and consequently blocks the catalytic property of a reactor. In the literature a carbon deposition regime is selected by thermodynamical analysis to design safe operation conditions. In the case of Computational Fluid Dynamic (CFD, hereafter) models each control volume should be investigated to determinate if carbon deposition is thermodynamically favourable. In this paper the authors combine equilibrium and kinetics analysis to simulate the steam reforming of methane-ethane rich fuel. The results of the computations were juxtaposed with experimental data for methane steam reforming, and good agreement was found. An analysis based on the kinetics of reactions was conducted to predict the influence of temperature drop and non-equilibrium composition on solid carbon deposition. It was found that strong non-uniform temperature distribution in the reactor causes conditions favourable for carbon deposition at the inlet of the reformer. It was shown that equilibrium calculations, often used in the literature, are insufficient.

  3. Coupling of high temperature nuclear reactor with chemical plant by means of steam loop with heat pump

    Directory of Open Access Journals (Sweden)

    Kopeć Mariusz

    2017-01-01

    Full Text Available High temperature nuclear reactors (HTR can be used as an excellent, emission-free source of technological heat for various industrial applications. Their outlet helium temperature (700°-900°C allows not only for heat supply to all processes below 600°C (referred to as “steam class”, but also enables development of clean nuclear-assisted hydrogen production or coal liquefaction technologies with required temperatures up to 900°C (referred to as “chemical class”. This paper presents the results of analyses done for various configurations of the steam transport loop coupled with the high-temperature heat pump designed for “chemical class” applications. The advantages and disadvantages as well as the key issues are discussed in comparison with alternative solutions, trying to answer the question whether the system with the steam loop and the hightemperature heat pump is viable and economically justified.

  4. Apparatus for inspecting and repairing a pressurized-water reactor's steam generator heat exchanger tubes

    International Nuclear Information System (INIS)

    Mueller, O.; Roettger, H.; Kasti, H.; Hagen, H.G.

    1976-01-01

    Described is an apparatus provided for use with a pressurized-water reactor' steam generator having a manifold chamber enclosing the bottom side of a horizontal tube sheet having holes therethrough in which are mounted the tubes of a heat exchanger tube bundle. The manifold chamber has a manhole giving access to the tube's bottom side to permit internal inspection or repair of the tubes by registration of an end of a flexible guide conduit with the tube sheet holes and through which a flexible carrier can be guided for insertion via these holes in the tube sheet and through the tubes extending from the tube sheet's other side

  5. Modelling of the processes of heat and mass transfer in adiabatic steam and drop flows

    International Nuclear Information System (INIS)

    Andrizhievskij, A.A.; Mikhalevich, A.A.; Nesterenko, V.B.; Trifonov, A.G.

    1983-01-01

    The mathematical models for investigating the local and integral characteristics of heat and mass transfer processes during simultaneous motion of adiabatic steam and drop flow and a flux of impurity particles are given. The mathematical model is constrUcted on the basis of one-dimensional stationary eqUations of conservation of mass, thermal energy and momentum of liquid and vapor phases. Dispersion composition of condensed moisture is described by the Nukiyama-Tanasava distribution function formed taking into account the Veber number critical value. Equations of motion and mass balance conservation for impurity particles are included into the mathematical model. These equations are considered as additional inactive phase

  6. Expandable antivibration bar for heat transfer tubes of a pressurized water reactor steam generator

    International Nuclear Information System (INIS)

    Appleman, R.H.

    1985-01-01

    An expandable antivibration bar for use in stabilizing the U-bend portion of heat transfer tubes in a pressurized water reactor steam generator comprises two adjustable rods connected together by an arcuate connector. The two adjustable rods preferably comprise two mating rod sections having complementary angular sliding surfaces thereon, with means provided to move the rod sections relative to each other along the sliding surfaces so as to expand the rods from a first mated cross-sectional width to a second larger cross-sectional width. The ends of the rod sections have means for aligning the two rod sections and maintaining them in alignment during expansion. (author)

  7. A performance analysis of integrated solid oxide fuel cell and heat recovery steam generator for IGFC system

    DEFF Research Database (Denmark)

    Rudra, Souman; Lee, Jinwook; Rosendahl, Lasse

    2010-01-01

    efficiencies can be achieved. The outputs from SOFC can be utilized by heat recovery steam generator (HRSG), which drives the steam turbine for electricity production. The SOFC stack model was developed using the process flow sheet simulator Aspen Plus, which is of the equilibrium type. Various ranges...... of syngas properties gathered from different literature were used for the simulation. The results indicate a trade-off efficiency and power with respect to a variety of SOFC inputs. The HRSG located after SOFC was included in the current simulation study with various operating parameters. This paper...... describes IGFC power plants, particularly the optimization of HRSG to improve the efficiency of the heat recovery from the SOFC exhaust gas and to maximize the power production in the steam cycle in the IGFC system. HRSG output from different pressure levels varies depending on the SOFC output. The steam...

  8. Steam Distillation with Induction Heating System: Analysis of Kaffir Lime Oil Compound and Production Yield at Various Temperatures

    International Nuclear Information System (INIS)

    Zuraida Muhammad; Zakiah Mohd Yusoff; Mohd Noor Nasriq Nordin

    2013-01-01

    The steam temperature during the extraction process has a great influence on the essential oil quality. .This study was conducted to analyze the compound of kaffir-lime oil during extracting at different steam temperature using GC-MS analysis. The extraction was carried out by using steam distillation based on induction heating system at different extraction temperature such as 90, 95 and 100 degree Celsius, the power of the induction heating system is fixed at 1.6 kW. Increment of the steam temperature will increase the oil yield. In terms of oil composition, extraction at lower temperature resulted high concentration for four marker compounds of kaffir-lime oil which are α-pinene, sabinene, limonene, β-pinene. (author)

  9. Heat and fuel coupled operation of a high temperature polymer electrolyte fuel cell with a heat exchanger methanol steam reformer

    Science.gov (United States)

    Schuller, G.; Vázquez, F. Vidal; Waiblinger, W.; Auvinen, S.; Ribeirinha, P.

    2017-04-01

    In this work a methanol steam reforming (MSR) reactor has been operated thermally coupled to a high temperature polymer electrolyte fuel cell stack (HT-PEMFC) utilizing its waste heat. The operating temperature of the coupled system was 180 °C which is significantly lower than the conventional operating temperature of the MSR process which is around 250 °C. A newly designed heat exchanger reformer has been developed by VTT (Technical Research Center of Finland LTD) and was equipped with commercially available CuO/ZnO/Al2O3 (BASF RP-60) catalyst. The liquid cooled, 165 cm2, 12-cell stack used for the measurements was supplied by Serenergy A/S. The off-heat from the electrochemical fuel cell reaction was transferred to the reforming reactor using triethylene glycol (TEG) as heat transfer fluid. The system was operated up to 0.4 A cm-2 generating an electrical power output of 427 Wel. A total stack waste heat utilization of 86.4% was achieved. It has been shown that it is possible to transfer sufficient heat from the fuel cell stack to the liquid circuit in order to provide the needed amount for vaporizing and reforming of the methanol-water-mixture. Furthermore a set of recommendations is given for future system design considerations.

  10. Device indicating start of steam or water reaction with sodium and damage of steam generator heat exchange tube wall

    International Nuclear Information System (INIS)

    Jung, J.; Sobotka, J.

    1984-01-01

    Eddy currents induced by the alternating current of an exciting coil in the vicinity of steam or water leakage are used for indication. The coil is supplied from a power amplifier whose input is connected to an exciting generator by two measuring coils connected across each other. Their voltage is applied to a differential amplifier with an indicator. The equipment may be used for steam generators of nuclear power plants with sodium cooled reactors. (E.F.)

  11. Energy recovery from waste incineration: Assessing the importance of district heating networks

    International Nuclear Information System (INIS)

    Fruergaard, T.; Christensen, T.H.; Astrup, T.

    2010-01-01

    Municipal solid waste incineration contributes with 20% of the heat supplied to the more than 400 district heating networks in Denmark. In evaluation of the environmental consequences of this heat production, the typical approach has been to assume that other (fossil) fuels could be saved on a 1:1 basis (e.g. 1 GJ of waste heat delivered substitutes for 1 GJ of coal-based heat). This paper investigates consequences of waste-based heat substitution in two specific Danish district heating networks and the energy-associated interactions between the plants connected to these networks. Despite almost equal electricity and heat efficiencies at the waste incinerators connected to the two district heating networks, the energy and CO 2 accounts showed significantly different results: waste incineration in one network caused a CO 2 saving of 48 kg CO 2 /GJ energy input while in the other network a load of 43 kg CO 2 /GJ. This was caused mainly by differences in operation mode and fuel types of the other heat producing plants attached to the networks. The paper clearly indicates that simple evaluations of waste-to-energy efficiencies at the incinerator are insufficient for assessing the consequences of heat substitution in district heating network systems. The paper also shows that using national averages for heat substitution will not provide a correct answer: local conditions need to be addressed thoroughly otherwise we may fail to assess correctly the heat recovery from waste incineration.

  12. Optimal design of district heating and cooling pipe network of seawater-source heat pump

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiang-li; Duanmu, Lin; Shu, Hai-wen [School of Civil and Hydraulic Engineering, Dalian University of Technology, Dalian, Liaoning Province 116024 (China)

    2010-01-15

    The district heating and cooling (DHC) system of a seawater-source heat pump is large system engineering. The investments and the operational cost of DHC pipe network are higher than a tradition system. Traditional design methods only satisfy the needs of the technology but dissatisfy the needs of the economy, which not only waste a mass of money but also bring problems to the operation, the maintenance and the management. So we build a least-annualized-cost global optimal mathematic model that comprises all constrict conditions. Furthermore, this model considers the variety of heating load and cooling load, the operational adjustment in different periods of the year. Genetic algorithm (GA) is used to obtain the optimal combinations of discrete diameters. Some operators of GA are selected to reduce the calculation time and obtain good calculation accuracy. This optimal method is used to the design of the DHC network of Xinghai Bay commercial district which is a real engineering. The design optimization can avoid the matter of the hydraulic unbalance of the system, enhance the running efficiency and greatly reduce the annualized-cost comparing with the traditional design method. (author)

  13. Financial cost-benefit analysis of investment possibilities in district heating system on wood residues

    Directory of Open Access Journals (Sweden)

    Stošić Ivan

    2017-01-01

    Full Text Available The purpose of this research is to provide feasibility analysis of a long-term sustainable development concept for district heating based on wood residues. In this paper, the experimental study has been conducted starting from the data collected by field researches in municipality of Trstenik (town in Serbia with district heating system currently based on heavy fuel oil and lignite. Using the method of Financial Cost-Benefit Analysis, this study evaluates financial efficiency of investment in district heating plant based on wood residues and energy savings in district heating system. Findings show that such investment could be profitable from the financial point of view: Net Present Value of investment is positive, Financial Rate of Return is high (30.69%, and the pay-back period is relatively favourable (7 years. Moreover, the presented SWOT indicates that there are realistic prospects of implementation of district heating based on wood residues. However, this does not mean everything will go smoothly and easily, keeping in mind a number of challenges that each new concept of district heating contains immanently. Nevertheless, the results of this research could provide useful inputs for the decision makers when selecting appropriate models for improving performance of municipal district heating systems.

  14. FOLA - the district heat supply project for the Olten-Aarau region

    International Nuclear Information System (INIS)

    Utzinger, E.

    1986-01-01

    The FOLA project envisages supply of nuclear power station heat via pipe lines to communities in the Olten-Aarau region. The project is introduced with reference to environmental and oil saving advantages. Heat from the nuclear power station steam circuit converted via heat exchangers would be transmitted through pressurised hot water pipe line networks to user communities for extraction by heat exchangers at consumer installations. Some network details are discussed. The exact supply area is not yet finalised, but estimated heat loading is about 150 MW. Following further studies a construction and operating company could be formed, and heat delivery could commence in 1989. (H.V.H.)

  15. Scale model test results for an inverted U-tube steam generator with comparisons to heat transfer correlations

    International Nuclear Information System (INIS)

    Boucher, T.J.

    1987-01-01

    To provide data for assessment and development of thermal-hydraulic computer codes, bottom main feedwater-line-break transient simulations were performed in a scale model (Semiscale Mod-2C) of a pressurized water reactor (PWR) with conditions typical of a PWR (15.0 MPa primary pressure, 600 K steam generator inlet plenum fluid temperatures, 6.2 MPa secondary pressure). The state-of-the-art measurements in the scale model (Type III) steam generator allow for the determination of U-tube steam generator allow for the determination of U-tube steam generator secondary component interactions, tube bundle local radial heat transfer, and tube bundle and riser vapor void fractions for steady state and transient operations. To enhance the understanding of the observed phenomena, the component interactions, local heat fluxes, local secondary convective heat transfer coefficients and local vapor void fractions are discussed for steady state, full-power and transient operations. Comparisons between the measurement-derived secondary convective heat transfer coefficients and those predicted by a number of correlations, including the Chen correlation currently used in thermal-hydraulic computer codes, show that none of the correlations adequately predict the data and points out the need for the formulation of a new correlation based on this experimental data. The unique information presented herein should be of the interest to anyone involved in modeling inverted U-tube steam generator thermal-hydraulics for forced convection boiling/vaporization heat transfer. 5 refs., 13 figs., 1 tab

  16. Modeling of pipe break accident in a district heating system using RELAP5 computer code

    International Nuclear Information System (INIS)

    Kaliatka, A.; Valinčius, M.

    2012-01-01

    Reliability of a district heat supply system is a very important factor. However, accidents are inevitable and they occur due to various reasons, therefore it is necessary to have possibility to evaluate the consequences of possible accidents. This paper demonstrated the capabilities of developed district heating network model (for RELAP5 code) to analyze dynamic processes taking place in the network. A pipe break in a water supply line accident scenario in Kaunas city (Lithuania) heating network is presented in this paper. The results of this case study were used to demonstrate a possibility of the break location identification by pressure decrease propagation in the network. -- Highlights: ► Nuclear reactor accident analysis code RELAP5 was applied for accident analysis in a district heating network. ► Pipe break accident scenario in Kaunas city (Lithuania) district heating network has been analyzed. ► An innovative method of pipe break location identification by pressure-time data is proposed.

  17. Analysis and research on promising solutions of low temperature district heating without risk of legionella

    DEFF Research Database (Denmark)

    Yang, Xiaochen; Li, Hongwei; Fog, Jette M.

    2014-01-01

    Most regulations of domestic hot water supply temperature is around 55-60 oC, which potentially requires higher district heating temperature. However, high supply temperature of district heating causes many problems, such as the high heating loss, and obstacles for applying renewable energy...... resources. The most crucial restriction for applying low temperature district heating is the worry about the breakout of legionella, which exists preferably in low temperature hot water systems. Several novel techniques such as electric tracing and flat station were investigated for such dilemma. The pros...... and cons were compared in this paper. Both the energy and economy saving ratios were analysed comparing with high temperature supply scenario. Furthermore, the viability of the applications in different types of buildings for low temperature district heating (LTDH) was also discussed by using dynamic...

  18. District heating and energy efficiency in detached houses of differing size and construction

    Energy Technology Data Exchange (ETDEWEB)

    Joelsson, Anna; Gustavsson, Leif [Ecotechnology, Department of Engineering, Physics and Mathematics, Mid Sweden University, SE-831 25 Oestersund (Sweden)

    2009-02-15

    House envelope measures and conversion of heating systems can reduce primary energy use and CO{sub 2} emission in the existing Swedish building stock. We analysed how the size and construction of electrically heated detached houses affect the potential for such measures and the potential for cogenerated district heating. Our starting point was two typical houses built in the 1970s. We altered the floor plans to obtain 6 houses, with heated floor space ranging between 100 and 306 m{sup 2}. One of the houses was also analysed for three energy standards with differing heat loss rates. CO{sub 2} emission, primary energy use and heating cost were estimated after implementing house envelope measures, conversions to other heating systems and changes in the generation of district heat and electricity. The study accounted for primary energy, including energy chains from natural resources to useful heat in the houses. We showed that conversion to district heating based on biomass, together with house envelope measures, reduced the primary energy use by 88% and the CO{sub 2} emission by 96%, while reducing the annual societal cost by 7%. The choice of end-use heating system was decisive for the primary energy use, with district heating being the most efficient. Neither house size nor energy standard did significantly change the ranking of the heating systems, either from a primary energy or an economic viewpoint, but did affect the extent of the annual cost reduction after implementing the measures. (author)

  19. District heating and energy efficiency in detached houses of differing size and construction

    International Nuclear Information System (INIS)

    Joelsson, Anna; Gustavsson, Leif

    2009-01-01

    House envelope measures and conversion of heating systems can reduce primary energy use and CO 2 emission in the existing Swedish building stock. We analysed how the size and construction of electrically heated detached houses affect the potential for such measures and the potential for cogenerated district heating. Our starting point was two typical houses built in the 1970s. We altered the floor plans to obtain 6 houses, with heated floor space ranging between 100 and 306 m 2 . One of the houses was also analysed for three energy standards with differing heat loss rates. CO 2 emission, primary energy use and heating cost were estimated after implementing house envelope measures, conversions to other heating systems and changes in the generation of district heat and electricity. The study accounted for primary energy, including energy chains from natural resources to useful heat in the houses. We showed that conversion to district heating based on biomass, together with house envelope measures, reduced the primary energy use by 88% and the CO 2 emission by 96%, while reducing the annual societal cost by 7%. The choice of end-use heating system was decisive for the primary energy use, with district heating being the most efficient. Neither house size nor energy standard did significantly change the ranking of the heating systems, either from a primary energy or an economic viewpoint, but did affect the extent of the annual cost reduction after implementing the measures

  20. District heating and cooling systems for communities through power plant retrofit and distribution network. Volume 3. Tasks 4-6. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Watt, J.R.; Sommerfield, G.A.

    1979-08-01

    Stone and Webster Engineering Corporation is a member of the Demonstration Team to review and assess the technical aspects of cogeneration for district heating. Task 4 details the most practical retrofit schemes. Of the cogeneration schemes studied, a back-pressure turbine is considered the best source of steam for district heating. Battelle Columbus Laboratories is a member of the Demonstration Team employed to investigate several institutional issues affecting the success of district heating. The Toledo Edison legal staff reviewed the legal aspects of mandate to serve, easement and franchise requirements, and corporate charter requirements. The principal findings of both the Battelle investigations and the legal research are summarized in Task 5. A complete discussion of each issue is included in the two sections labeled Legal Issues and Institutional Issues. In Task 6, Battelle Columbus Laboratories completed a preliminary economic analysis, incorporating accurate input parameters applicable to utility ownership of the proposed district-heating system. The methodology used is summarized, the assumptions are listed, and the results are briefly reviewed.

  1. Comparative analysis of the district heating systems of two towns in Croatia and Denmark

    DEFF Research Database (Denmark)

    Čulig-Tokić, Dario; Krajačić, Goran; Doračić, Borna

    2015-01-01

    This paper compares district heating systems in Zagreb and Aalborg in order to see their similarities and differences from which conclusions are drawn on how to improve the systems. The method chosen is the comparative analysis. Data is organized and structured so to allow clear and concise...... comparison. The results of the comparative analysis show that the district heating system in Aalborg is more advanced than the district heating system in Zagreb. This advantage is prominent in aspects of supply, demand, distribution and economic spheres. Some of the possible improvements include lowering...

  2. Analysis of energy development sustainability: The example of the lithuanian district heating sector

    International Nuclear Information System (INIS)

    Kveselis, Vaclovas; Dzenajavičienė, Eugenija Farida; Masaitis, Sigitas

    2017-01-01

    Today, sustainable energy development is one of key issues on European development agenda. The article describes one of sustainable energy development promoting tool - the eco-labelling scheme for district heating and cooling systems elaborated within the framework of Intelligent Energy for Europe program project “Ecoheat4cities” and partially funded by European Agency for Competitiveness and Innovation. The scheme is based on measured energy and environmental performance data of the district heating and cooling system and considers primary non-renewable energy usage together with the share of renewable energy and carbon dioxide emissions calculated using life-cycle analysis methodology. The “power bonus” approach is used for performance indicators of the heat generated in cogeneration installations. An analysis of a number of Lithuanian district heating companies using elaborated labelling criteria shows positive trends towards fulfilling Lithuania's energy policy goals. The labelling scheme gives opportunity for policy makers and urban planners to compare different heat supply options and decide upon exploiting district heating advantages and benefits for reaching EU energy and environment policy goals. - Highlights: • Overview of Lithuania's district heating sector was performed via main sustainability criteria. • Developing to greener and more efficient state was disclosed via analysis of three years activity results. • Green labelling may help district heating companies to maintain existing and attract new potential consumers.

  3. Economic impact of latent heat thermal energy storage systems within direct steam generating solar thermal power plants with parabolic troughs

    International Nuclear Information System (INIS)

    Seitz, M.; Johnson, M.; Hübner, S.

    2017-01-01

    Highlights: • Integration of a latent heat thermal energy storage system into a solar direct steam generation power cycle. • Parametric study of solar field and storage size for determination of the optimal layout. • Evaluation of storage impact on the economic performance of the solar thermal power plant. • Economic comparison of new direct steam generation plant layout with state-of-the-art oil plant layout. - Abstract: One possible way to further reduce levelized costs of electricity of concentrated solar thermal energy is to directly use water/steam as the primary heat transfer fluid within a concentrated collector field. This so-called direct steam generation offers the opportunity of higher operating temperatures and better exergy efficiency. A technical challenge of the direct steam generation technology compared to oil-driven power cycles is a competitive storage technology for heat transfer fluids with a phase change. Latent heat thermal energy storages are suitable for storing heat at a constant temperature and can be used for direct steam generation power plants. The calculation of the economic impact of an economically optimized thermal energy storage system, based on a latent heat thermal energy storage system with phase change material, is the main focus of the presented work. To reach that goal, a thermal energy storage system for a direct steam generation power plant with parabolic troughs in the solar field was thermally designed to determine the boundary conditions. This paper discusses the economic impact of the designed thermal energy storage system based on the levelized costs of electricity results, provided via a wide parametric study. A state-of-the-art power cycle with a primary and a secondary heat transfer fluid and a two-tank thermal energy storage is used as a benchmark technology for electricity generation with solar thermal energy. The benchmark and direct steam generation systems are compared to each other, based respectively

  4. The potential to supply low temperature district heating to existing building area

    DEFF Research Database (Denmark)

    Li, Hongwei; Svendsen, Svend

    2013-01-01

    Low-temperature district heating (LTDH) has the advantages as reduced network heat loss, improved quality match between energy supply and energy demand, and increased utilization of low-grade waste heat and renewable energy. The LTDH represents the next generation district heating (DH) system...... to supply existing building areas which are characterized with high heating demand needs to be examined. In this paper, the DH network deliverable capacity to supply LTDH to an existing building area is studied based on building thermal performance and DH network hydraulic performance simulation....

  5. Modeling of a District Heating System and Optimal Heat-Power Flow

    Directory of Open Access Journals (Sweden)

    Wentao Yang

    2018-04-01

    Full Text Available With ever-growing interconnections of various kinds of energy sources, the coupling between a power distribution system (PDS and a district heating system (DHS has been progressively intensified. Thus, it is becoming more and more important to take the PDS and the DHS as a whole in energy flow analysis. Given this background, a steady state model of DHS is first presented with hydraulic and thermal sub-models included. Structurally, the presented DHS model is composed of three major parts, i.e., the straight pipe, four kinds of local pipes, and the radiator. The impacts of pipeline parameters and the environment temperature on heat losses and pressure losses are then examined. The term “heat-power flow” is next defined, and the optimal heat-power flow (OHPF model formulated as a quadratic planning problem, in which the objective is to minimize energy losses, including the heat losses and active power losses, and both the operational constraints of PDS and DHS are respected. The developed OHPF model is solved by the well-established IPOPT (Interior Point OPTimizer commercial solver, which is based on the YALMIP/MATLAB toolbox. Finally, two sample systems are served for demonstrating the characteristics of the proposed models.

  6. Characterization of elevated temperature properties of heat exchanger and steam generator alloys

    International Nuclear Information System (INIS)

    Wright, J.K.; Carroll, L.J.; Cabet, C.; Lillo, T.M.; Benz, J.K.; Simpson, J.A.; Lloyd, W.R.; Chapman, J.A.; Wright, R.N.

    2012-01-01

    The Next Generation Nuclear Plant project is considering Alloy 800H and Alloy 617 for steam generator and intermediate heat exchangers. It is envisioned that a steam generator would operate with reactor outlet temperatures from 750 to 800 °C, while an intermediate heat exchanger for primary to secondary helium would operate up to an outlet temperature of 950 °C. Although both alloys are of interest due in part to their technical maturity, a number of specific properties require further characterization for design of nuclear components. Strain rate sensitivity of both alloys has been characterized and is found to be significant above 600 °C. Both alloys also exhibit dynamic strain aging, characterized by serrated flow, over a wide range of temperatures and strain rates. High temperature tensile testing of Alloy 617 and Alloy 800H has been conducted over a range of temperatures. Dynamic strain aging is a concern for these materials since it is observed to result in reduced ductility for many solid solution alloys. Creep, fatigue, and creep–fatigue properties of Alloy 617 have been measured as well, with the goal of determining the influence of the temperature, strain rate and atmosphere on the creep–fatigue life of Alloy 617. Elevated temperature properties and implications for codification of the alloys will be described.

  7. Characterization of Elevated Temperature Properties of Heat Exchanger and Steam Generator Alloys

    International Nuclear Information System (INIS)

    Wright, J.K.; Carroll, L.J.; Benz, J.K.; Simpson, J.A.; Wright, R.N.; Lloyd, W.R.; Chapman, J.A.

    2010-01-01

    The Next Generation Nuclear Plant project is considering Alloy 800H and Alloy 617 for steam generator and intermediate heat exchangers. It is envisioned that a steam generator would operate with reactor outlet temperatures from 750 to 800 C, while an intermediate heat exchanger for primary to secondary helium would operate up to an outlet temperature of 950 C. Although both alloys are of interest due in part to their technical maturity, a number of specific properties require further characterization for design of nuclear components. Strain rate sensitivity of both alloys has been characterized and is found to be significant above 600 C. Both alloys also exhibit dynamic strain aging, characterized by serrated flow, over a wide range of temperatures and strain rates. In general dynamic strain aging is observed to begin at higher temperatures and serrated flow persists to higher temperatures in Alloy 617 compared to Alloy 800H. Dynamic strain aging is a concern for these materials since it is observed to result in reduced ductility for many solid solution alloys. The role of dynamic strain aging in the creep-fatigue behavior of Alloy 617 at temperatures of 800 C and above has also been examined in detail. Serrated flow is found to persist in cyclic stress-strain curves up to nearly the cycle to failure in some temperature and strain regimes. Results of those experiments and implications for creep-fatigue testing protocols will be described.

  8. Performance evaluation of a biomass boiler on the basis of heat loss method and total heat values of steam

    International Nuclear Information System (INIS)

    Munir, A.; Alvi, J.Z.; Ashfaq, S.; Ghafoor, A.

    2014-01-01

    Pakistan being an agricultural country has large resources of biomass in the form of crop residues like wood, wheat straw, rice husk, cotton sticks and bagasse. Power generation using biomass offers an excellent opportunity to overcome current scenario of energy crises. Of the all biomass resources, bagasse is one of the potential energy sources which can be successfully utilized for power generation. During the last decade, bagasse fired boilers attained major importance due to increasing prices of primary energy (e.g. fossil fuels). Performance of a bagasse fired boiler was evaluated at Shakarganj Sugar Mill, Bhone-Jhang having steam generation capacity of 80 tons h/sup -1/at 25 bar working pressure. The unit was forced circulation and bi-drum type water tube boiler which was equipped with all accessories like air heater, economizer and super-heater. Flue gas analyzer and thermocouples were used to record percent composition and temperature of flue gases respectively. Physical analysis of bagasse showed gross calorific value of bagasse as 2326 kCal kg/sup -1/. Ultimate analysis of bagasse was performed and the actual air supplied to the boiler was calculated to be 4.05 kg per kg of bagasse under the available resources of the plant. Performance evaluation of the boiler was carried out and a complete heat balance sheet was prepared to investigate the different sources of heat losses. The efficiency of the boiler was evaluated on the basis of heat losses through boiler and was found to be 56.08%. It was also determined that 2 kg of steam produced from 1 kg of bagasse under existing condition of the boiler. The performance evaluation of the boiler was also done on the basis of total heat values of steam and found to be 55.98%. The results obtained from both the methods were found almost similar. Effects of excess air, stack and ambient temperature on the efficiency of boiler have also been evaluated and presented in the manuscript. (author)

  9. The demand function for residential heat through district heating system and its consumption benefits in Korea

    International Nuclear Information System (INIS)

    Lim, Seul-Ye; Kim, Hyo-Jin; Yoo, Seung-Hoon

    2016-01-01

    The demand for residential heat (RH) through a district heating system (DHS) has been and will be expanded in Korea due to its better performance in energy efficiency and the abatement of greenhouse gas emissions than decentralized boilers. The purposes of this paper are two-fold. The first is to obtain the demand function for DHS-based RH in Korea and investigate the price and income elasticities of the demand employing the quarterly data covering the period 1988–2013. The short-run price and income elasticities are estimated as −0.700 and 0.918, respectively. Moreover, the long-run elasticities are −1.253 and 1.642, respectively. The second purpose is to measure the consumption benefits of DHS-based-RH employing the economic theory that they are the sum of the actual payment and consumer surplus for the consumption. Considering that the average price and estimated consumer surplus of the DHS-based RH use in 2013 are computed to be KRW 87,870 (USD 84.1) and KRW 62,764 (USD 60.1) per Gcal, the consumption benefits of the DHS-based RH are calculated to be KRW 150,634 (USD 144.2) per Gcal. This information can be beneficially utilized to conduct an economic feasibility study for a new DHS project related to RH supply. - Highlights: • Demand for residential heat (RH) from district heating system (DHS) is expanding. • We estimate the demand function for and consumption benefits of DHS-based RH. • Short-run price and income elasticities are −0.700 and 0.918, respectively. • Long-run price and income elasticities are −1.253 and 1.642, respectively. • Consumption benefits of DHS-based RH are KRW 150,634 (USD 144.2) per Gcal.

  10. Development of Design Criteria for Fluid Induced Structural Vibrations in Steam Generators and Heat Exchangers

    International Nuclear Information System (INIS)

    Catton, Ivan; Dhir, Vijay K.; Alquaddoomi, O.S.; Mitra, Deepanjan; Adinolfi, Pierangelo

    2004-01-01

    OAK-B135 Flow-induced vibration in heat exchangers has been a major cause of concern in the nuclear industry for several decades. Many incidents of failure of heat exchangers due to apparent flow-induced vibration have been reported through the USNRC incident reporting system. Almost all heat exchangers have to deal with this problem during their operation. The phenomenon has been studied since the 1970s and the database of experimental studies on flow-induced vibration is constantly updated with new findings and improved design criteria for heat exchangers. In the nuclear industry, steam generators are often affected by this problem. However, flow-induced vibration is not limited to nuclear power plants, but to any type of heat exchanger used in many industrial applications such as chemical processing, refrigeration and air conditioning. Specifically, shell and tube type heat exchangers experience flow-induced vibration due to the high velocity flow over the tube banks. Flow-induced vibration in these heat exchangers leads to equipment breakdown and hence expensive repair and process shutdown. The goal of this research is to provide accurate measurements that can help modelers to validate their models using the measured experimental parameters and thereby develop better design criteria for avoiding fluid-elastic instability in heat exchangers. The research is divided between two primary experimental efforts, the first conducted using water alone (single phase) and the second using a mixture of air or steam and water as the working fluid (two phase). The outline of this report is as follows: After the introduction to fluid-elastic instability, the experimental apparatus constructed to conduct the experiments is described in Chapter 2 along with the measurement procedures. Chapter 3 presents results obtained on the tube array and the flow loop, as well as techniques used in data processing. The project performance is described and evaluated in Chapter 4 followed by

  11. Prospects of SMSNR development in Switzerland and the influence of the evolution of district heating networks

    International Nuclear Information System (INIS)

    Foskolos, K.; Brogli, R.

    1992-01-01

    Small dedicated heating reactors have been developed in Switzerland between 1985 and 1988. Two technological lines (HTGR and LWR) were under consideration. Although air pollution and particularly CO 2 emission are recognized as critical mid-term environmental problems, no break-through has been achieved for nuclear district heating current; centralized heat supply shares only an insignificant part of the heat market. The main criteria for selection of energy supply systems are still of financial nature, and the high investment connected to heat distribution networks makes district heating less attractive to customers and investors. SMSNR will have a chance to enter the heat market, if heating networks are already widely established. To achieve this, a shift of public opinion towards more general criteria has to take place, encouraged by governmental intervention. Size and nature of heating networks will be a decisive factor for the definition of the optimum plant size of a SMSNR. (orig.)

  12. Prospects of SMSNR development in Switzerland and the influence of the evolution of district heating networks

    International Nuclear Information System (INIS)

    Foskolos, K.; Brogli, R.

    1991-01-01

    Small dedicated heating reactors have been developed in Switzerland in the last five years. Two technological lines (HTGR and LWR) are still under consideration. Although air pollution and particularly CO 2 emission are recognized as critical midterm environmental problems, no breakthrough has been achieved for nuclear district heating; centralized heat supply shares only an insignificant part of the heat market. The main criteria for selection of energy supply systems are still of financial nature, and the high investment connected to heat distribution networks makes district heating less attractive to customers and investors. MSNR will have a chance to enter the heat market, if heating networks are already widely established. To achieve this, a shift of public opinion towards more general criteria has to take place, encouraged by governmental intervention. Size and nature of heating networks will be a decisive factor for the definition of the optimum plant size of a SMSNR. (author)

  13. Potential of biocorrosion in Danish district heatings sytems

    Energy Technology Data Exchange (ETDEWEB)

    Kjellerup, B.V.; Olesen, B.H.; Froelund, B. [Danish Technological Institute, Dep. of Environment Teknologiparken, Arhus (Denmark); Nielsen, P.H. [Aalborg University, Department of Life Sciences, Aalborg (Denmark)

    2004-07-01

    Danish district heating (DH) systems utilise water with unique characteristics that include low conductivity, high pH, nutrient poor and anaerobic (oxygen free) conditions in order to reduce corrosion rates. This survey was carried out in order to investigate the potential for biofilm formation and biocorrosion in these systems. Determination of total bacterial numbers in water samples were performed in 29 DH systems and showed a range of 10{sup 2}-10{sup 5} cells . ml{sup -1}. The potential for biofilm growth was further examined in corrosion monitoring units located at 6 DH locations. Total bacterial numbers in biofilm on mild steel were found in the range of 10{sup 4}-10{sup 6} cells . cm{sup -2}. The mild steel coupons were examined for general corrosion rates based on weight loss together with an investigation of pitting corrosion. The general corrosion rates were up to 12 {mu}m . year{sup -1}, while the pitting analysis showed pit depths up to 90 {mu}m for half a year of exposure. Presence of sulphate reducing bacteria (SRB) was found in all systems tested with corrosion monitoring units, whereas sulphide was found to different extents in the biofilms on all mild steel coupons. It was shown that DH systems with the highest number of bacteria in the biofilm generally had the most pronounced corrosion. The results show that despite the nutrient poor environment in the DH systems the potential for biofilm formation and biocorrosion was present. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

  14. Corrosion allowances for sodium heated steam generators: evaluation of effects and extrapolation to component life time

    Energy Technology Data Exchange (ETDEWEB)

    Grosser, E E; Menken, G

    1975-07-01

    Steam generator tubes are subjected to two categories of corrosion; metal/sodium reactions and metal/water-steam interactions. Referring to these environmental conditions the relevant parameters are discussed. The influences of these parameters on the sodium corrosion and water/steam-reactions are evaluated. Extrapolations of corrosion values to steam generator design conditions are performed and discussed in detail. (author)

  15. Corrosion allowances for sodium heated steam generators: evaluation of effects and extrapolation to component life time

    International Nuclear Information System (INIS)

    Grosser, E.E.; Menken, G.

    1975-01-01

    Steam generator tubes are subjected to two categories of corrosion; metal/sodium reactions and metal/water-steam interactions. Referring to these environmental conditions the relevant parameters are discussed. The influences of these parameters on the sodium corrosion and water/steam-reactions are evaluated. Extrapolations of corrosion values to steam generator design conditions are performed and discussed in detail. (author)

  16. Environmental Assessment for the Bison School District Heating Plant Project, Institutional Conservation Program (ICP)

    International Nuclear Information System (INIS)

    1995-01-01

    This environmental assessment analyzes the environmental impacts of replacing the Bison, South Dakota School District's elementary school and high school heating system consisting of oil-fired boilers and supporting control system and piping

  17. Master plan study - District heating Sillamaee municipality. Estonia. Final report. Appendices for chapter 9

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    The appendices to the final report on the master plan study on district heating in the municipality in Estonia, chapter nine, gives data related to general economic assumptions for financial and economic calculations, fuel consumption, financing, prices, fuel consumption. (ARW)

  18. Combined heat and power plants with parallel tandem steam turbines; Smaaskalig kraftvaerme med parallellkopplade tandemturbiner

    Energy Technology Data Exchange (ETDEWEB)

    Steinwall, Pontus; Norstroem, Urban; Pettersson, Camilla; Oesterlin, Erik

    2004-12-01

    We investigate the technical and economical conditions for a concept with parallel coupled tandem turbines in small scale combined heat and power plants fired with bio-fuel and waste. Performance and heat production costs at varying electricity prices for the concept with two smaller tandem coupled steam turbines has been compared to the traditional concept with one single multi-staged turbine. Three different types of plants have been investigated: - Bio fuelled CHP plant with thermal capacity of 15 MW{sub th}; - Waste fired CHP plant with thermal capacity of 20 MW{sub th}; - Bio fuelled CHP plant with thermal capacity of 25 MW{sub th}. The simple steam turbines (Curtis turbines) used in the tandem arrangement has an isentropic efficiency of about 49 to 53% compared to the multi-staged steam turbines with isentropic efficiency in the range of 59% to 81%. The lower isentropic efficiency for the single staged turbines is to some extent compensated at partial load when one of the two turbines can be shut down leading to better operational conditions for the one still in operation. For concepts with saturated steam at partial load below 50% the tandem arrangements presents higher electricity efficiency than the conventional single turbine alternative. The difference in annual production of electricity is therefore less than the difference in isentropic efficiency for the two concepts. Production of electricity is between 2% and 42% lower for the tandem arrangements in this study. Investment costs for the turbine island has been calculated for the two turbine concepts and when the costs for turbines, generator, power transmission, condensing system, piping system, buildings, assembling, commissioning and engineering has been added the sum is about the same for the two concepts. For the bio-fuelled plant with thermal capacity of 15 MW{sub th} the turbine island amount to about 10-12 MSEK and about 13-15 MSEK for the waste fired plant with a thermal capacity of 20 MW

  19. Flare Temperature and Nitrogen Oxide Emission Reduction and Heat Transfer in the TGMP-314I Steam Boiler Firebox

    Energy Technology Data Exchange (ETDEWEB)

    Makarov, A. N., E-mail: tgtu-kafedra-ese@mail.ru [Tver’ State Technical University (Russian Federation)

    2016-07-15

    Asolution is given to the problem of heat transfer in the firebox of a steam boiler, taking account of the radiation from all quadrillions of atoms constituting the flare. An innovative firebox for a steam boiler is proposed: the lower part of the firebox is a rectangular parallelepiped and the upper part a four-sided pyramid. The calculations show that in the proposed firebox the nonuniformity of the heat-flux distribution is diminished along the height and perimeter of the walls and nitrogen oxide emissions are reduced.

  20. Intermediate heat exchanger and steam generator designs for the HYLIFE-II fusion power plant using molten salts

    International Nuclear Information System (INIS)

    Lee, Y.T.; Hoffman, M.A.

    1992-01-01

    The HYLIFE-II fusion power plant employs the molten salt, Flibe, for the liquid jets which form the self-healing 'first wall' of the reactor. The molten salt, sodium fluoroborate then transports the heat from the IHX's to the steam generators. The design and optimization of the IHX's and the steam generators for use with molten salts has been done as part of the HYLIFE-II conceptual design study. The results of this study are described, and reference designs of these large heat exchangers are selected to minimize the cost of electricity while satisfying other important constraints

  1. Design of serially connected ammonia-water hybrid absorption-compression heat pumps for district heating with the utilisation of a geothermal heat source

    DEFF Research Database (Denmark)

    Jensen, Jonas Kjær; Ommen, Torben Schmidt; Markussen, Wiebke Brix

    2016-01-01

    District heating (DH) can reduce the primary energy consumption in urban areas with significant heat demands. The design of a serially connected ammonia-water hybrid absorption-compression heat pump system was investigated for operation in the Greater Copenhagen DH network in Denmark, in order...... to supply 7.2 MW heat at 85 °C utilizing a geothermal heat source at 73 °C. Both the heat source and heat sink experience a large temperature change over the heat transfer process, of which a significant part may be achieved by direct heat exchange. First a generic study with a simple representation...

  2. Electricity supply, district heating and supply of natural- and gas-works gas 1998

    International Nuclear Information System (INIS)

    2000-01-01

    This report is based on information covering enterprises producing, selling and transmitting electrical energy or producing and distributing hot water for district heating. The producers of electricity included in this report have either at least 100 kW in prime movers for electrical generation or at least 400 kW in prime movers and no public distribution. Enterprises are obliged by law to report these data. Data are requested concerning three types of statistical units: power stations, heating plants, and units reporting complete economic information (deliveries, sales value, production costs etc.). Power stations may be regarded as technical units and data are collected on technical equipment, consumption of fuels, production and own consumption of electrical energy. For heating plants data are collected on production and turnover of steam and hot water and on consumption of fuels and electrical energy. At the end of 1998 the installed capacity of generators amounted to 34 389 MW. Hydro-electrical capacity accounted for 48 % of total installed capacity. Compared to 1997 the capacity increased by 55 MW for hydro-electrical power and, decreased by 254 MW for conventional thermal power. Total capacity decreased by 147 MW or 0.4 %. The net production of electrical energy in 1998 amounted to 154 552 GWh, an increase of 6.4 % compared to 1997 The production of hydro-electrical power increased by 8.2 %. Hydro-electrical power accounted for 47 % of total production. Nuclear-power production increased by 6.2 % Conventional thermal-power production decreased by 28.9 %. The consumption of electricity (excl. transmission losses) increased by 0,8 % to 133 096 GWh. By consumption sectors the percentage changes were: in agriculture, etc. -9.9 %; in mining, quarrying and manufacturing +2.2 %; in construction -7.8 %; in electricity, heating, gas and water services -4.6 %; in commerce, real estate, etc. +1.8 %; in transport, storage and communication -2.9 %; in community, social

  3. Method for optimal design of pipes for low-energy district heating, with focus on heat losses

    DEFF Research Database (Denmark)

    Dalla Rosa, Alessandro; Li, Hongwei; Svendsen, Svend

    2011-01-01

    The synergy between highly energy-efficient buildings and low-energy district heating (DH) systems is a promising concept for the optimal integration of energy-saving policies and energy supply systems based on renewable energy (RE). Network transmission and distribution heat loss is one of the k...

  4. Reactors for heat production and the development of district heating in France

    International Nuclear Information System (INIS)

    Ricateau, P.

    1977-01-01

    Hitherto the development of nuclear power engineering has been based on the generation of electricity, and even of base-load electricity for feeding into a grid covering an entire country. Definition of the service to be rendered by a nuclear power station was thus extremely simple, namely to supply electricity throughout the year at the lowest possible cost and with the maximum possible reliability. Between the reactor on the one hand and the consumers on the other - consumers whose requirements are very diverse and who are geographically widely scattered - the grid forms a sort of screen so that the optimization of the reactor hardly depends at all on the configuration of the remainder of the transmission and distribution system. The production of heat involves totally different problems, for two essential reasons: (a) the limited economic range for the distribution of heat which limits the reactor to a specific group of consumers, and (b) the fact that the temperature, unlike the electrical potential, cannot be transformed at will but drops continuously between production and consumption of the heat. The temperature of the reactor must be matched to the nature of consumer demand and to the distance over which the heat must be transported. The heat balance thus appears to be like that of a system in which source, transmission and utilization are closely related. In these conditions the solutions will depend on numerous factors and one should not be surprised at finding different applications of nuclear power not only from one country to another but even from one area to another within the same country. The author first outlines the characteristics of the demand for district heating in France and then examines the types of nuclear plant which seem best suited for this purpose in the French context. (author)

  5. Renewable energy in district heating grids. A realistic perspective?; Erneuerbare Energien in Waermenetzen. Eine realistische Perspektive?

    Energy Technology Data Exchange (ETDEWEB)

    Bruns, Elke [Technische Univ. Berlin (Germany). Inst. fuer Landschaftsarchitektur und Umweltplanung; Futterlieb, Matthias; Ohlhorst, Doerte [Technische Univ. Berlin (Germany). Zentrum Technik und Gesellschaft (ZTG); Wenzel, Bernd [Ingenieurbuero fuer neue Energie (IfnE), Teltow (Germany)

    2012-09-15

    The heating sector holds high potentials for cutting CO{sub 2} emissions by using renewable energy. These potentials can be tapped either by substituting fossil fuels in individual heating units or by using renewable energy in district heating networks, which may be more efficient. This paper asks for the options to increase the share of renewable energy in Germany's district heating infrastructure and for the restrictions that are hampering further development in this field. It critically discusses the relevant technical, political and economic challenges and determinants. District heating networks fuelled by renewable energy are not only competing with fossil fuels in individual heating units. They are also facing the more fundamental question regarding the preconditions for a profitable and worthwhile operation of grid-bound heat supply. The economic viability of heat grids has to be analyzed on a case-by-case basis, since it depends predominantly on individual framework conditions. Those include a decreasing heat demand due to improving energy performance of buildings, competing gas grids already in place and the complex interest structures of the actors involved. The growth rates that were observed in the last years were predominantly achieved in small renewably fuelled district heating networks. Even under favourable framework conditions, there is a need for additional supportive measures to increase the share of renewable energy in district heating grids. This mix of policy instruments should encompass measures to increase the implementation rates of municipal heat utilization concepts, measures to decrease the initial investments needed, as well as public relations to improve the user perception of grid-bound heat supply. However, the options to increase the share of renewable heat in existing large-scale grids are considered to be rather limited. (orig.)

  6. Steam generator blowdown heat exchangers degradations operational experience on EDF French NPP fleet

    International Nuclear Information System (INIS)

    Praud, M.; Doyen, F.; Wintergest, M.; Jourdain, W.; Roussillon, M.; Zidane, A.; Mayos, M.

    2015-01-01

    The main function of the Steam Generator Blowdown System (SGBS) is to purify the secondary fluid from all kinds of pollutions: corrosion products from the secondary system, consequences of raw water pollutions through condenser's leakage, potential radiochemical pollutions resulting from Primary-to-Secondary leaks. The topic of this paper is to present the main SGBS dysfunctions linked to the degradation of the tubular heat exchangers, which sometimes can lead to integrity failure, through corrosion phenomenon. The degradation mechanisms have been characterized by various visual inspections and destructive examinations performed on pulled tubes and bundles. It appears that SGBS tubes suffer two main forms of corrosion. First, for the non-regenerative heat exchangers, where external surface of tubes is exposed to intermediate fluid, alkaline corrosion under tube sheet or shell-side baffles may occur. Caustic attack results from Na 3 PO 4 decomposition by thermal or chemical process. Secondly, mainly for regenerative heat exchangers, pitting and under-deposits corrosion linked to lay-up conditions during outages. This kind of attack is the root cause of a potential 'domino effect': a steam jet from the leaking tube can induce mechanical and/or erosion on many tubes located in its vicinity. Concerning the external degradation by caustic corrosion, only design modifications and strong monitoring of the raw water inlet may able to limit the occurrence of tube perforation. The lay-up guidelines should be carefully followed to mitigate internal corrosion: a controlled atmosphere (limited humidity) and cleanliness of the tube (avoiding deposits formation on the bottom line) seem to be the main parameters

  7. Optimization of a local district heating plant under fuel flexibility and performance

    DEFF Research Database (Denmark)

    Rudra, Souman; Rosendahl, Lasse; From, Niels

    2011-01-01

    are calculated for various local fuels in energyPRO. A comparison has been made between the reference model and the basis for individual solutions. The greatest reduction in heat price is obtained by replacing one engine with a new biogas where heat production is divided by 66% of biogas, 13% natural gas engines......, an investigation has been made to reduce the use of fossil fuels for district heating system and make use of the local renewable resources (Biogas, Solar and Geothermal) for district heating purpose. In this article, the techno-economic assessment is achieved through the development of a suite of models...

  8. Heat transport analysis in a district heating and snow melting system in Sapporo and Ishikari, Hokkaido applying waste heat from GTHTR300

    International Nuclear Information System (INIS)

    Kasahara, Seiji; Kamiji, Yu; Terada, Atsuhiko; Yan Xing; Inagaki, Yoshiyuki; Murata, Tetsuya; Mori, Michitsugu

    2015-01-01

    A district heating and snow melting system utilizing waste heat from Gas Turbine High temperature Gas Reactor of 300 MW_e (GTHTR300), a heat-electricity cogeneration design of high temperature gas-cooled reactor, was analyzed. Application areas are set in Sapporo and Ishikari, the heavy snowfall cities in Northern Japan. The heat transport analyses are carried out by modeling the components in the system; pipelines of the secondary water loops between GTHTR300s and heat demand district and heat exchangers to transport the heat from the secondary water loops to the tertiary loops in the district. Double pipe for the secondary loops are advantageous for less heat loss and smaller excavation area. On the other hand, these pipes has disadvantage of more electricity consumption for pumping. Most of the heat demand in the month of maximum requirement can be supplied by 2 GTHTR300s and delivered by 9 secondary loops and around 5000 heat exchangers. Closer location of GTHTR300 site to the heat demand district is largely advantageous economically. Less decrease of the distance from 40 km to 20 km made the heat loss half and cost of the heat transfer system 22% smaller. (author)

  9. Cooperation within the district heating industry; Zusammenarbeit in der Fernwaermebranche. Wirtschaftliche und sichere Versorgung mit Fernwaerme

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, H. [Arbeitsgemeinschaft fuer Waerme und Heizkraftwirtschaft - AGFW - e.V., Frankfurt am Main (Germany)

    2003-05-01

    Safeguarding the know-how, to define the minimum requirements, to sensitise the business partner to reach a sufficient product quality and a fair order processing are the basic elements for a future-oriented business cooperation. To define the minimum requirements for the German district heating industry, the German District Heating Association (AGFW) has developed a set of regulations (AGFW-regulations). In the connection it was very important to regulate only the minimum requirements, which are defined, adopted and above all realised by all players in the district heating industry. The aim is to offer the customer the product district heat with the least effort, in the claimed quality, with acceptable prices and with a moderate revenue for the district heat company. This is the basis for an economic and secure district heat supply. (orig.) [German] Know-how-Sicherung, Definition der Mindestanforderungen, Sensibilisierung der Partner fuer ein ausreichendes Qualitaetsniveau und faire partnerschaftliche Auftragsabwicklung sind die Grundlagen einer zukunftsorientierten Zusammenarbeit. Die Definition der technischen Mindestanforderungen erfolgt fuer die Fernwaermebranche im AGFW-Regelwerk. Hierbei ist es wichtig darauf zu achten, dass nur die Mindestanforderungen festgeschrieben werden, die im Konsens zwischen allen Akteuren der Branche definiert, akzeptiert und vor allem im Rahmen der Standardisierung umgesetzt werden. (orig.)

  10. Experimental investigations of heat exchange and hydrodynamics on models of a VG-400 steam generator tube bundle made up of small diameter helicoils

    International Nuclear Information System (INIS)

    Golovko, V.F; Ivaskov, N.A.; Obukhov, P.I.; Pospelov, V.N.; Sergeev, A.I.

    1988-01-01

    Features of HTGR steam generators having heat exchange surface made up of small diameter helicoils are discussed in the paper. A general approach to optimization of thermohydraulic characteristics BΓW-400 steam generator design backed by calculation and experiment are given. Main results of steam generator assembly's model aerodynamic test are presented. Data of thermohydraulic tests of a single tube model in a helium heated test rig are discussed. (author)

  11. Vilnius district heating pilot project. Final report. Annex 1-14

    International Nuclear Information System (INIS)

    1995-03-01

    The present energy scenario model is based on the SYSTEM ROERNET energy planning module and includes the energy flows from the energy source to the consumer for space heating and domestic hot water. The energy sources are: District heating of City based on CHP or/and heat-only production. District heating of Naujoji Vilnia based on heat-only production. Local boilers using natural gas or heavy fuel oil. Stoves using kerosene, coke or wood. (Electricity panel might be included, but this has not been the case in the actual analyses). The calculations of the energy model results in estimation of: Annual heat production, especially simulation of the plant production for district heating system with the possibility of integrated pooled operation by giving an order of priority to each plant based on the efficiency of the plant. Annual fuel consumption and the fuel costs for the society. Annual electricity production and its value to the society. Annual operation and maintenance costs including costs connected with consumption of electricity for district heating purposes. The total annual investments due to the set of options applied in the scenario in question. Savings in plant investments if less production capacity is necessary in scenarios where the heat demand is decreasing. The flue gas emissions from the heat and CHP production in the Vilnius area are estimated by CO 2 , SO 3 , NO x and particulates. These emissions are not reduced by the possible savings of electricity production of a reference power-only plant outside Vilnius. (EG)

  12. Investigations of the gas-side heat transfer and flow characteristics of steam generators in AGR stations

    Energy Technology Data Exchange (ETDEWEB)

    Lis, J [Central Electricity Research Laboratories, Leatherhead, Surrey (United Kingdom)

    1984-07-01

    This paper describes the experimental and analytical investigations of the gas-side heat transfer and flow characteristics of steam generators in the AGR stations carried out by CERL. The majority of the experimental work on heat transfer and flow characteristics of close-packed tube arrangements in cross-flow of gases is carried out in a pressurised heat exchanger rig. The rig is operated on-line by a dedicated PDP 11/40 computer over the range of Reynolds number 10{sup 4} to 3x10{sup 5}. Atmospheric wind tunnels employing either small or large scale models of the specific sections of steam generators are used for a variety of supplementary and development studies. Various measurements techniques and, in particular, LDA and hot wire anemometry employed in these studies are described. The more important aspects of various investigations are illustrated by typical results. In order to ensure the efficient operation and integrity of steam generators under asymmetric boundary conditions a MIX suite of 2-dimensional codes has been developed. The codes calculate the gas and water/steam flow and temperature distributions in each channel of the steam generator taking into account thermal mixing in the gas as it passes through the generator. Application of the MIX codes to the solution of various operational problems is illustrated by typical examples and the continuing exercise of validating the codes against plant operational data is discussed. (author)

  13. Contrastive experimental study on heat transfer and friction characteristics in steam cooled and air cooled rectangular channels with rib turbulators

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Jianying; Li, Guojun; Gao, Tieyu [Xian Jiaotong University, Xian (China)

    2014-09-15

    The present experiment compares the heat transfer and friction characteristics in steam cooled and air cooled rectangular channels (simulating a gas turbine blade cooling passage) with two opposite rib-roughened walls. The Reynolds number (Re) whose length scale is the hydraulic diameter of the passage is set within the range of 10000-60000. The channel length is 1000 mm. The pitch-to-rib height ratio, the channel aspect ratio and the channel blockage ratio is 10, 0.5 and 0.047, respectively. It is found that the average Nu, the average friction coefficient, and the heat transfer performance of both steam and air in the ribbed channels show almost the same change trend with the increase of Re. Under the same test conditions, the average Nu of steam is 30.2% higher than that of air, the average friction coefficient is 18.4% higher, and the heat transfer performances of steam on the ribbed and the smooth walls are 8.4% and 7.3% higher than those of air, respectively. In addition, semi-empirical correlations for the two test channels are developed, which can predict the Nu under the given test condition. The correlations can be used in the design of the internal cooling passage of new generation steam cooled gas turbine blade/vane.

  14. Investigations of the gas-side heat transfer and flow characteristics of steam generators in AGR stations

    International Nuclear Information System (INIS)

    Lis, J.

    1984-01-01

    This paper describes the experimental and analytical investigations of the gas-side heat transfer and flow characteristics of steam generators in the AGR stations carried out by CERL. The majority of the experimental work on heat transfer and flow characteristics of close-packed tube arrangements in cross-flow of gases is carried out in a pressurised heat exchanger rig. The rig is operated on-line by a dedicated PDP 11/40 computer over the range of Reynolds number 10 4 to 3x10 5 . Atmospheric wind tunnels employing either small or large scale models of the specific sections of steam generators are used for a variety of supplementary and development studies. Various measurements techniques and, in particular, LDA and hot wire anemometry employed in these studies are described. The more important aspects of various investigations are illustrated by typical results. In order to ensure the efficient operation and integrity of steam generators under asymmetric boundary conditions a MIX suite of 2-dimensional codes has been developed. The codes calculate the gas and water/steam flow and temperature distributions in each channel of the steam generator taking into account thermal mixing in the gas as it passes through the generator. Application of the MIX codes to the solution of various operational problems is illustrated by typical examples and the continuing exercise of validating the codes against plant operational data is discussed. (author)

  15. Decentralized substations for low-temperature district heating with no Legionella risk, and low return temperatures

    International Nuclear Information System (INIS)

    Yang, Xiaochen; Li, Hongwei; Svendsen, Svend

    2016-01-01

    To improve energy efficiency and give more access to renewable energy sources, low-temperature district heating (LTDH) is a promising concept to be realized in the future. However, concern about Legionella proliferation restricts applying low-temperature district heating in conventional systems with domestic hot water (DHW) circulation. In this study, a system with decentralized substations was analysed as a solution to this problem. Furthermore, a modification for the decentralized substation system were proposed in order to reduce the average return temperature. Models of conventional system with medium-temperature district heating, decentralized substation system with LTDH, and innovative decentralized substation system with LTDH were built based on the information of a case building. The annual distribution heat loss and the operating costs of the three scenarios were calculated and compared. From the results, realizing LTDH by the decentralized substation unit, 30% of the annual distribution heat loss inside the building can be saved compared to a conventional system with medium-temperature district heating. Replacing the bypass pipe with an in-line supply pipe and a heat pump, the innovative decentralized substation system can reduce distribution heat loss by 39% compared to the conventional system and by 12% compared to the normal decentralized substation system with bypass. - Highlights: • The system of decentralized substations can realize low-temperature district heating without running the risk of Legionella. • Decentralized substations help reduce the distribution heat loss inside the building compared to conventional system. • A new concept that can reduce the return temperature for district heating is proposed and analysed.

  16. Modelling temperature dynamics of a district heating system in Naestved, Denmark-A case study

    International Nuclear Information System (INIS)

    Gabrielaitiene, Irina; Bohm, Benny; Sunden, Bengt

    2007-01-01

    Modelling the temperature dynamics of a district heating system is typically validated for a single pipe or a system with limited information about dynamic consumer behaviour. In the present work, time dependent consumer data from the Naestved district heating system was used to investigate the ability of modelling tools to represent the temperature profile distortion throughout an entire heating system network. The Naestved district heating subsystem was modelled by two approaches (the node method developed at the Technical University of Denmark and the software TERMIS), and these modelling results were compared with measured data. The results indicate that the discrepancies between the predicted and measured temperatures are pronounced for consumers located in pipelines at distant pipelines containing numerous bends and fittings. Additionally, it was found that representing the consumer behaviour on an annual average basis introduced a deviation between the predicted and the measured return temperatures at the heat source

  17. Building an eco-effective district heating management system in a city

    Directory of Open Access Journals (Sweden)

    Gitelman Leonid

    2016-01-01

    Full Text Available The goal of making the urban environment safer amid increasing human impact adds to the importance of district heating management. The article outlines the results of a study into the problem of improving the urban environment by implementing two innovative solutions. Technological innovations imply the introduction of modern sustainable tools of reducing emissions in district heating networks, one of them being the combination of district heating and combined heat and power plants (a case study of Turin. Organizational innovations are built upon the management of demand for thermal energy that makes it possible to reduce investment in new construction and to optimize the architecture of heat load schedules for the purpose of alleviating energy and environmental pressure on the city. The authors propose formats and areas of demand side management for thermal energy and methods of offering economic incentives to program participants.

  18. Regional Energy Planning Tool for Renewable Integrated Low-Energy District Heating Systems

    DEFF Research Database (Denmark)

    Tol, Hakan; Dincer, Ibrahim; Svendsen, Svend

    2013-01-01

    Low-energy district heating systems, operating at low temperature of 55 °C as supply and 25°C as return, can be the energy solution as being the prevailing heating infrastructure in urban areas, considering future energy schemesaiming at increased exploitation of renewable energy sources together...... with low-energy houses in focus with intensified energy efficiency measures. Employing low-temperature operation allows the ease to exploit not only any type of heat source but also low-grade sources, i.e., renewable and industrial waste heat, which would otherwise be lost. In this chapter, a regional...... energy planning tool is described considered with various energy conversion systems based on renewable energy sources to be supplied to an integrated energy infrastructure involving a low-energy district heating, a district cooling, and an electricity grid. The developed tool is performed for two case...

  19. The Convenience Benefits of the District Heating System over Individual Heating Systems in Korean Households

    Directory of Open Access Journals (Sweden)

    Hyo-Jin Kim

    2017-08-01

    Full Text Available Koreans usually prefer the district heating system (DHS to the individual heating system (IHS because DHS can give them convenience and safety within their living environment. The Korean government thus plans to expand the DHS and requires information about the value that consumers place on the DHS over the IHS, which has not been dealt with in academic literature. This paper attempts to investigate Korean households’ willingness to pay (WTP for DHS over IHS, for residential heat (RH. To this end, the authors apply the dichotomous choice contingent valuation to assessing additional WTP for DHS using a survey of 1000 randomly selected households living in buildings with IHS. A mixture model is applied to deal with the zero WTP responses. The WTP distribution is specified as a mixture of two distributions, one with a point mass at zero and the other with full support on the positive half of the real line. The results show that the mean additional WTP for DHS-based RH over IHS-based RH is estimated to be KRW 5775 (USD 5.4 per Gcal. This value can be interpreted as the consumer’s convenience benefits of DHS over IHS, and amounts to approximately 6.0% of the average price: KRW 96,510 (USD 90.4 per Gcal in 2013, for IHS-based RH. This information is useful for evaluating changes to the method used for supplying RH from IHS to DHS.

  20. Electricity supply, district heating and supply of natural and gasworks gas 1999

    International Nuclear Information System (INIS)

    2001-01-01

    Total domestic use of electricity (including transmission losses) was 143.3 TWh in 1999. This represents a decrease of 0.5 per cent compared to 1998. Usage in the household sector fell by 1.5 per cent to 34.3 TWh (including second homes). In contrast, the industry sector (manufacturing industry, mining and quarrying) increased its usage by 1.1 per cent to 55.3 TWh. Deliveries of steam and hot water for district heating were 43.7 TWh, unchanged compared to 1998. Total net production of electricity decreased in 1999 by 2.5 per cent compared to 1998 and amounted to 150.8 TWh. Hydroelectric production decreased by 4.0 per cent to 70.9 TWh. The production of conventional thermal power also fell, by 5.6 per cent to 9.4 TWh. Nuclear power contributed 70.2 TWh, almost the same as the previous year. Wind power, however, increased its production by 16.2 per cent to 358 GWh. Imports of electricity increased by 0.4 TWh to 8.5 TWh, but exports decreased by 0.9 TWh to 15.9 TWh. Total deliveries of natural gas to final consumers diminished somewhat in 1999 and amounted to 854 million m 3 (equivalent to 9226 GWh). Deliveries of natural gas substitutes (air/liquefied petroleum gas mix) decreased by 5 per cent to 26 million m 3 . The mean price of natural gas rose by approximately 6 per cent compared to 1998. Deliveries of gas-works gas fell in 1999 by 0.6 million m 3 to 109.2 million m 3 . The mean price was about 11 per cent higher than in the preceding year

  1. Utilisation of bleed steam heat to increase the upper heat source temperature in low-temperature ORC

    Science.gov (United States)

    Mikielewicz, Dariusz; Mikielewicz, Jarosław

    2011-12-01

    In the paper presented is a novel concept to utilize the heat from the turbine bleed to improve the quality of working fluid vapour in the bottoming organic Rankine cycle (ORC). That is a completely novel solution in the literature, which contributes to the increase of ORC efficiency and the overall efficiency of the combined system of the power plant and ORC plant. Calculations have been accomplished for the case when available is a flow rate of low enthalpy hot water at a temperature of 90 °C, which is used for preliminary heating of the working fluid. That hot water is obtained as a result of conversion of exhaust gases in the power plant to the energy of hot water. Then the working fluid is further heated by the bleed steam to reach 120 °C. Such vapour is subsequently directed to the turbine. In the paper 5 possible working fluids were examined, namely R134a, MM, MDM, toluene and ethanol. Only under conditions of 120 °C/40 °C the silicone oil MM showed the best performance, in all other cases the ethanol proved to be best performing fluid of all. Results are compared with the "stand alone" ORC module showing its superiority.

  2. District heating rehabilitation project in Kaerdla on Hiiumaa, Estonia. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    The main objective of the project has been to assist Kaerdla Municipality with the rehabilitation of their district heating system with Danish technology, and thereby support and make it possible for the Municipality of Kaerdla to develop the district heating sector in Kaerdla and thereby also to reduce emissions of harmful gases to the environment, as well as making a much more rational and energy efficient system. The project would further on demonstrate the use of pre-insulated pipes, which are fully sealed against penetration of water as well as demonstrate the use of compact units as substations including weather compensation control systems for regulation of heat and hot tap water supply for the district heating consumers. Besides the project gives significantly decreases in energy consumption`s and in the pollution from the production of energy, the objective of the project was also to put great stress on providing technical assistance to Kaerdla DH company, in order to make them capable in operation and maintenance of the new district heating system, and also to train the local operational staff in operation of the complete district heating system. The project will have a high demonstration value towards other towns in Estonia with similar problems and configurations of their heating systems. (EG)

  3. District heating rehabilitation project in Kaerdla on Hiiumaa, Estonia. Final report

    International Nuclear Information System (INIS)

    1998-03-01

    The main objective of the project has been to assist Kaerdla Municipality with the rehabilitation of their district heating system with Danish technology, and thereby support and make it possible for the Municipality of Kaerdla to develop the district heating sector in Kaerdla and thereby also to reduce emissions of harmful gases to the environment, as well as making a much more rational and energy efficient system. The project would further on demonstrate the use of pre-insulated pipes, which are fully sealed against penetration of water as well as demonstrate the use of compact units as substations including weather compensation control systems for regulation of heat and hot tap water supply for the district heating consumers. Besides the project gives significantly decreases in energy consumption's and in the pollution from the production of energy, the objective of the project was also to put great stress on providing technical assistance to Kaerdla DH company, in order to make them capable in operation and maintenance of the new district heating system, and also to train the local operational staff in operation of the complete district heating system. The project will have a high demonstration value towards other towns in Estonia with similar problems and configurations of their heating systems. (EG)

  4. Geothermal district heating applications in Turkey: a case study of Izmir-Balcova

    Energy Technology Data Exchange (ETDEWEB)

    Hepbasli, A. [Ege Univ., Dept. of Mechanical Engineering, Izmir (Turkey); Canakci, C. [Izmir-Balcova Geothermal Energy Inc., Izmir (Turkey)

    2003-05-01

    Turkey is located on the Mediterranean sector of the Alpine-Himalayan Tectonic Belt and is among the first seven countries in abundance of geothermal resources around the world. However, the share of its potential used is only about 2%. This means that considerable studies on geothermal energy could be conducted in order to increase the energy supply and to reduce atmospheric pollution in Turkey. The main objective in doing the present study is twofold, namely: (a) to overview the status and future aspects of geothermal district heating applications in Turkey and (b) to present the Izmir-Balcova geothermal district heating system, which is one example of the high temperature district heating applications in Turkey. The first geothermal heating application was applied in 1981 to the Izmir-Balcova thermal facilities, where the downhole heat exchanger was also used for the first time. Besides this, the first city based geothermal district heating system has been operated in Balikesir-Gonen since 1987. Recently, the total installed capacity has reached 820 MW{sub t} for direct use. An annual average growth of 23% of the residences connected to geothermal district heating systems has been achieved since 1983 in the country, representing a decrease of 5% in the last three years. Present applications have shown that in Turkey, geothermal energy is much cheaper than the other energy sources, like fossil fuels, and can make a significant contribution towards reducing the emission of greenhouse gases. (Author)

  5. Techno-economic analysis of energy renovation measures for a district heated multi-family house

    International Nuclear Information System (INIS)

    Gustafsson, Marcus; Gustafsson, Moa Swing; Myhren, Jonn Are; Bales, Chris; Holmberg, Sture

    2016-01-01

    Highlights: • Energy saving measures can be cost-effective as part of a planned renovation. • Primary energy consumption, non-renewable energy consumption and CO_2 emissions are assessed for different electricity mixes. • EAHP can be a cost-effective and environmentally beneficial complement to district heating. • EAHP has lower LCC and significantly shorter payback time than ventilation with heat recovery. • Low-temperature ventilation radiators improve the COP of the heat pump. - Abstract: Renovation of existing buildings is important in the work toward increased energy efficiency and reduced environmental impact. The present paper treats energy renovation measures for a Swedish district heated multi-family house, evaluated through dynamic simulation. Insulation of roof and façade, better insulating windows and flow-reducing water taps, in combination with different HVAC systems for recovery of heat from exhaust air, were assessed in terms of life cycle cost, discounted payback period, primary energy consumption, CO_2 emissions and non-renewable energy consumption. The HVAC systems were based on the existing district heating substation and included mechanical ventilation with heat recovery and different configurations of exhaust air heat pump. Compared to a renovation without energy saving measures, the combination of new windows, insulation, flow-reducing taps and an exhaust air a heat pump gave up to 24% lower life cycle cost. Adding insulation on roof and façade, the primary energy consumption was reduced by up to 58%, CO_2 emissions up to 65% and non-renewable energy consumption up to 56%. Ventilation with heat recovery also reduced the environmental impact but was not economically profitable in the studied cases. With a margin perspective on electricity consumption, the environmental impact of installing heat pumps or air heat recovery in district heated houses is increased. Low-temperature heating improved the seasonal performance factor of the

  6. Containment fan cooler heat transfer calculation during main steam line break for Maanshan PWR plant

    Energy Technology Data Exchange (ETDEWEB)

    Yuann, Yng-Ruey, E-mail: ryyuann@iner.gov.tw; Kao, Lain-Su, E-mail: lskao@iner.gov.tw

    2013-10-15

    Highlights: • Evaluate component cooling water (CCW) thermal response during MSLB for Maanshan. • Using GOTHIC to calculate CCW temperature and determine time required to boil CCW. • Both convective and condensation heat transfer from the air side are considered. • Boiling will not occur since T{sub B} is sufficiently longer than CCW pump restart time. -- Abstract: A thermal analysis has been performed for the Containment Fan Cooler Unit (FCU) during Main Steam Line Break (MSLB) accident, concurrent with loss of offsite power, for Maanshan PWR plant. The analysis is performed in order to address the waterhammer and two-phase flow issues discussed in USNRC's Generic Letter 96-06 (GL 96-06). Maanshan plant is a twin-unit Westinghouse 3-loop PWR currently operated at rated core thermal power of 2822 MWt for each unit. The design basis for containment temperature is Main Steam Line Break (MSLB) accident at power of 2830.5 MWt, which results in peak vapor temperature of 387.6 °F. The design is such that when MSLB occurs concurrent with loss of offsite power (MSLB/LOOP), both the coolant pump on the secondary side and the fan on the air side of the FCU loose power and coast down. The pump has little inertia and coasts down in 2–3 s, while the FCU fan coasts down over much longer period. Before the pump is restored through emergency diesel generator, there is potential for boiling the coolant in the cooling coils by the high-temperature air/steam mixture entering the FCU. The time to boiling depends on the operating pressure of the coolant before the pump is restored. The prediction of the time to boiling is important because it determines whether there is potential for waterhammer or two-phase flow to occur before the pump is restored. If boiling occurs then there exists steam region in the pipe, which may cause the so called condensation induced waterhammer or column closure waterhammer. In either case, a great amount of effort has to be spent to

  7. Summary of results from sodium-heated steam generator test program

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, J S

    1975-07-01

    A 28 MWt sodium-heated steam generator test unit developed and fabricated by Atomics International was operated in the Sodium Component Test Installation. The SCTI is located at the Liquid Metal Engineering Center which is operated for the Atomic Energy Commission by Atomics International, Reviewed in this paper are the results of the test operations and the findings of the post-test examination of the module. Testing was performed to assure the mechanical integrity of the unit over a wide range of simulated plant operating conditions and to develop a variety of performance data. Specific tests conducted included preheat, vibration, startup-shutdown, pressurization, steady state and parametric performance mapping, endurance, simulated leak injection, low- flow stability and simulated plant transients. (author)

  8. Calculation of wastage by small water leaks in sodium heated steam generators

    International Nuclear Information System (INIS)

    Tregonning, K.

    1976-01-01

    On the basis of mechanistic arguments it is suggested that the temperature of the wasting surface would provide a single physically meaningful parameter with which to correlate wastage data. A lumped parameter model is developed which predicts reaction temperature as a function of the major variables in the small water leak situation (Leak rate, tube spacing, sodium temperature). The calculated temperatures explain much of the observed behaviour of wastage rate with these variables and compare well with the limited temperature data available. Wastage rates are correlated with predicted temperature on a total activation energy basis. The results are encouraging and a first conservative method for the calculation of wastage by small water leaks in sodium-heated steam generators is produced

  9. Qualitative and Quantitative Analysis of Organic Impurities in Feedwater of a Heat-Recovery Steam Generator

    Science.gov (United States)

    Chichirov, A. A.; Chichirova, N. D.; Filimonova, A. A.; Gafiatullina, A. A.

    2018-03-01

    In recent years, combined-cycle units with heat-recovery steam generators have been constructed and commissioned extensively in the European part of Russia. By the example of the Kazan Cogeneration Power Station no. 3 (TETs-3), an affiliate of JSC TGK-16, the specific problems for most power stations with combined-cycle power units that stem from an elevated content of organic impurities in the feedwater of the heat-recovery steam generator (HRSG) are examined. The HRSG is fed with highly demineralized water in which the content of organic carbon is also standardized. It is assumed that the demineralized water coming from the chemical water treatment department of TETs-3 will be used. Natural water from the Volga River is treated to produce demineralized water. The results of a preliminary analysis of the feedwater demonstrate that certain quality indices, principally, the total organic carbon, are above the standard values. Hence, a comprehensive investigation of the feedwater for organic impurities was performed, which included determination of their structure using IR and UV spectroscopy techniques, potentiometric measurements, and element analysis; determination of physical and chemical properties of organic impurities; and prediction of their behavior in the HRSG. The estimation of the total organic carbon revealed that it exceeded the standard values in all sources of water comprising the feedwater for the HRSG. The extracted impurities were humic substances, namely, a mixture of humic and fulvic acids in a 20 : 80 ratio, respectively. In addition, an analysis was performed of water samples taken at all intermediate stages of water treatment to study the behavior of organic substances in different water treatment processes. An analysis of removal of the humus substances in sections of the water treatment plant yielded the concentration of organic substances on the HRSG condensate. This was from 100 to 150 μg/dm3. Organic impurities in boiler water can induce

  10. Preliminary estimations on the heat recovery method for hydrogen production by the high temperature steam electrolysis

    International Nuclear Information System (INIS)

    Koh, Jae Hwa; Yoon, Duck Joo

    2009-01-01

    As a part of the project 'development of hydrogen production technologies by high temperature electrolysis using very high temperature reactor', we have developed an electrolyzer model for high temperature steam electrolysis (HTSE) system and carried out some preliminary estimations on the effects of heat recovery on the HTSE hydrogen production system. To produce massive hydrogen by using nuclear energy, the HTSE process is one of the promising technologies with sulfur-iodine and hybrid sulfur process. The HTSE produces hydrogen through electrochemical reaction within the solid oxide electrolysis cell (SOEC), which is a reverse reaction of solid oxide fuel cell (SOFC). The HTSE system generally operates in the temperature range of 700∼900 .deg. C. Advantages of HTSE hydrogen production are (a) clean hydrogen production from water without carbon oxide emission, (b) synergy effect due to using the current SOFC technology and (c) higher thermal efficiency of system when it is coupled nuclear reactor. Since the HTSE system operates over 700 .deg. C, the use of heat recovery is an important consideration for higher efficiency. In this paper, four different heat recovery configurations for the HTSE system have been investigated and estimated

  11. Preliminary design of steam reformer in out-pile demonstration test facility for HTTR heat utilization system

    Energy Technology Data Exchange (ETDEWEB)

    Haga, Katsuhiro; Hino, Ryutaro; Inagaki, Yosiyuki; Hata, Kazuhiko; Aita, Hideki; Sekita, Kenji; Nishihara, Tetsuo; Sudo, Yukio [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Yamada, Seiya

    1996-11-01

    One of the key objectives of HTTR is to demonstrate effectiveness of high-temperature nuclear heat utilization system. Prior to connecting a heat utilization system to HTTR, an out-pile demonstration test is indispensable for the development of experimental apparatuses, operational control and safety technology, and verification of the analysis code of safety assessment. For the first heat utilization system of HTTR, design of the hydrogen production system by steam reforming is going on. We have proposed the out-pile demonstration test plan of the heat utilization system and conducted preliminary design of the test facility. In this report, design of the steam reformer, which is the principal component of the test facility, is described. In the course of the design, two types of reformers are considered. The one reformer contains three reactor tubes and the other contains one reactor tube to reduce the construction cost of the test facility. We have selected the steam reformer operational conditions and structural specifications by analyzing the steam reforming characteristics and component structural strength for each type of reformer. (author)

  12. Swedish district heating—A system in stagnation: Current and future trends in the district heating sector

    International Nuclear Information System (INIS)

    Magnusson, Dick

    2012-01-01

    This paper argues that Sweden’s old and established district heating sector is heading into a stagnation phase. The aim is to analyse the factors influencing this development as well as the strategies used by involved parties to prevent stagnation. Using large technical system theory, I analyse internal and external factors potentially causing stagnation. The most obvious external factors are: an increase in the number of energy-efficient buildings, in response to stricter energy policies, which reduces the future potential for district heating in new and existing buildings; climate change; competition from other heating systems; and market saturation in the key sector, multi-dwelling buildings. The main internal factor is changed business strategies following electricity market deregulation, when energy companies were supposed to be run on businesslike terms. I also argue that stagnation can be defined as occurring when the key measure feature of a system, in this case, heat load is starting to stagnate or decline, even though the trend is positive in other areas. The strategies for avoiding stagnation are various forms of broadening scope, primarily by focusing more on electricity production by building combined heat and power plants, or using the alternative value of the technical system for new applications. - Highlights: ► The Swedish district heating sector is heading into a stage of stagnation. ► The main reasons are: climate change, competition and energy efficient buildings. ► Strategies to change trend: broadening of scope by focusing on electricity in CHP plants. ► Contribution to Large Technical Systems—theory and the later phases of system development.

  13. Optimization of Temperature Schedule Parameters on Heat Supply in Power-and-Heat Supply Systems

    Directory of Open Access Journals (Sweden)

    V. A. Sednin

    2009-01-01

    Full Text Available The paper considers problems concerning optimization of a temperature schedule in the district heating systems with steam-turbine thermal power stations having average initial steam parameters. It has been shown in the paper that upkeeping of an optimum network water temperature permits to increase an energy efficiency of heat supply due to additional systematic saving of fuel. 

  14. Feasibility study for the district heating reactor as applied to a desalting plan