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Sample records for mittels organic-rankine-cycle turbogenerator

  1. Altheim geothermal power plant electricity generation by means of an organic rankine cycle turbogenerator; Geothermienanlage Altheim - Stromerzeugung mittels Organic-Rankine-Cycle-Turbogenerator

    Energy Technology Data Exchange (ETDEWEB)

    Pernecker, G. [Marktgemeindeamt Altheim (Austria)

    1996-10-01

    The present paper reports on a project in Altheim in Upper Austria aiming to produce electricity by means of an Organic Rankine Cycle Turbogenerator using low-temperature thermal water. This could help improve the technical and economic situation of the goethermal power plant in operation there. (orig.) [Deutsch] Der Bericht beschreibt das Vorhaben der Marktgemeinde Altheim in Oberoesterreich Strom mittels eines Organic-Rankine-Cycle-Turbogenerators unter Verwendung niedrig temperierten Thermalwassers zu produzieren. Das Ziel bzw. der Zweck des Projektes ist es, die technische und wirtschaftliche Situation der bestehenden Geothermieanlage zu verbessern. (orig.)

  2. Altheim geothermal plant. Power generation by means of an ORC turbogenerator; Geothermieanlagen Altheim. Stromerzeugung mittels Organic-Rankine-Cycle Turbogenerator

    Energy Technology Data Exchange (ETDEWEB)

    Pernecker, G. [Marktgemeindeamt Altheim (Austria)

    1997-12-01

    The report describes the project of the Austrian market town of Altheim to generate electricity by means of an ORC turbogenerator using low-temperature thermal water. The project is to improve the technical and economic situation of the existing industrial-scale geothermal project. (orig.) [Deutsch] Der Bericht beschreibt das Vorhaben der Marktgemeinde Altheim in Oberoesterreich, Strom mittels eines Organic-Rankine-Cycle-Turbogenerators unter Verwendung niedrig temperierten Thermalwassers zu produzieren. Ziel bzw. der Zweck des Projektes ist es, die technische und wirtschaftliche Situation der bestehenden Grossthermieanlage zu verbessern. (orig.)

  3. Part-Load Performance of a Wet Indirectly Fired Gas Turbine Integrated with an Organic Rankine Cycle Turbogenerator

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Nguyen, Tuong-Van; Mazzucco, Andrea

    2014-01-01

    ) fueled by woodchips and an organic Rankine cycle (ORC) turbogenerator. An exergy analysis is performed to identify the sources of inefficiencies, the optimal design variables, and the most suitable working fluid for the organic Rankine process. This step enables to parametrize the part-load model...

  4. Part-Load Performance of aWet Indirectly Fired Gas Turbine Integrated with an Organic Rankine Cycle Turbogenerator

    Directory of Open Access Journals (Sweden)

    Leonardo Pierobon

    2014-12-01

    Full Text Available Over the last years, much attention has been paid to the development of efficient and low-cost power systems for biomass-to-electricity conversion. This paper aims at investigating the design- and part-load performance of an innovative plant based on a wet indirectly fired gas turbine (WIFGT fueled by woodchips and an organic Rankine cycle (ORC turbogenerator. An exergy analysis is performed to identify the sources of inefficiencies, the optimal design variables, and the most suitable working fluid for the organic Rankine process. This step enables to parametrize the part-load model of the plant and to estimate its performance at different power outputs. The novel plant has a nominal power of 250 kW and a thermal efficiency of 43%. The major irreversibilities take place in the burner, recuperator, compressor and in the condenser. Toluene is the optimal working fluid for the organic Rankine engine. The part-load investigation indicates that the plant can operate at high efficiencies over a wide range of power outputs (50%–100%, with a peak thermal efficiency of 45% at around 80% load. While the ORC turbogenerator is responsible for the efficiency drop at low capacities, the off-design performance is governed by the efficiency characteristics of the compressor and turbine serving the gas turbine unit.

  5. Organic rankine cycle fluid

    Science.gov (United States)

    Brasz, Joost J.; Jonsson, Ulf J.

    2006-09-05

    A method of operating an organic rankine cycle system wherein a liquid refrigerant is circulated to an evaporator where heat is introduced to the refrigerant to convert it to vapor. The vapor is then passed through a turbine, with the resulting cooled vapor then passing through a condenser for condensing the vapor to a liquid. The refrigerant is one of CF.sub.3CF.sub.2C(O)CF(CF.sub.3).sub.2, (CF.sub.3).sub.2 CFC(O)CF(CF.sub.3).sub.2, CF.sub.3(CF.sub.2).sub.2C(O)CF(CF.sub.3).sub.2, CF.sub.3(CF.sub.2).sub.3C(O)CF(CG.sub.3).sub.2, CF.sub.3(CF.sub.2).sub.5C(O)CF.sub.3, CF.sub.3CF.sub.2C(O)CF.sub.2CF.sub.2CF.sub.3, CF.sub.3C(O)CF(CF.sub.3).sub.2.

  6. Organic rankine cycle waste heat applications

    Energy Technology Data Exchange (ETDEWEB)

    Brasz, Joost J.; Biederman, Bruce P.

    2007-02-13

    A machine designed as a centrifugal compressor is applied as an organic rankine cycle turbine by operating the machine in reverse. In order to accommodate the higher pressures when operating as a turbine, a suitable refrigerant is chosen such that the pressures and temperatures are maintained within established limits. Such an adaptation of existing, relatively inexpensive equipment to an application that may be otherwise uneconomical, allows for the convenient and economical use of energy that would be otherwise lost by waste heat to the atmosphere.

  7. Cascaded organic rankine cycles for waste heat utilization

    Science.gov (United States)

    Radcliff, Thomas D.; Biederman, Bruce P.; Brasz, Joost J.

    2011-05-17

    A pair of organic Rankine cycle systems (20, 25) are combined and their respective organic working fluids are chosen such that the organic working fluid of the first organic Rankine cycle is condensed at a condensation temperature that is well above the boiling point of the organic working fluid of the second organic Rankine style system, and a single common heat exchanger (23) is used for both the condenser of the first organic Rankine cycle system and the evaporator of the second organic Rankine cycle system. A preferred organic working fluid of the first system is toluene and that of the second organic working fluid is R245fa.

  8. Optimal design of compact organic Rankine cycle units for domestic solar applications

    DEFF Research Database (Denmark)

    Barbazza, Luca; Pierobon, Leonardo; Mirandola, Alberto

    2014-01-01

    Organic Rankine cycle turbogenerators are a promising technology to transform the solar radiation harvested by solar collectors into electric power. The present work aims at sizing a small-scale organic Rankine cycle unit by tailoring its design for domestic solar applications. Stringent design...... criteria, i.e., compactness, high performance and safe operation, are targeted by adopting a multi-objective optimization approach modeled with the genetic algorithm. Design-point thermodynamic variables, e.g., evaporating pressure, the working fluid, minimum allowable temperature differences....... Findings also suggest that the evaporator and condenser minimum allowable temperature differences have the largest impact on the system volume and on the cycle performances. Among the fluids considered, the results indicate that R1234yf and R1234ze are the best working fluid candidates. Using flat plate...

  9. Organic rankine cycle system for use with a reciprocating engine

    Science.gov (United States)

    Radcliff, Thomas D.; McCormick, Duane; Brasz, Joost J.

    2006-01-17

    In a waste heat recovery system wherein an organic rankine cycle system uses waste heat from the fluids of a reciprocating engine, provision is made to continue operation of the engine even during periods when the organic rankine cycle system is inoperative, by providing an auxiliary pump and a bypass for the refrigerant flow around the turbine. Provision is also made to divert the engine exhaust gases from the evaporator during such periods of operation. In one embodiment, the auxiliary pump is made to operate simultaneously with the primary pump during normal operations, thereby allowing the primary pump to operate at lower speeds with less likelihood of cavitation.

  10. Organic Rankine Cycle with Solar Heat Storage in Paraffin Way

    Directory of Open Access Journals (Sweden)

    Constantin LUCA

    2015-06-01

    Full Text Available The paper presents an electricity generation system based on an Organic Rankine Cycle and proposed storing the amount of the heat produced by the solar panels using large volume of paraffin wax. The proposed working fluid is R-134a refrigerant. The cycle operates at very low temperatures. A efficiency of 6,55% was obtained.

  11. Optimal design of compact organic Rankine cycle units for domestic solar applications

    Directory of Open Access Journals (Sweden)

    Barbazza Luca

    2014-01-01

    Full Text Available Organic Rankine cycle turbogenerators are a promising technology to transform the solar radiation harvested by solar collectors into electric power. The present work aims at sizing a small-scale organic Rankine cycle unit by tailoring its design for domestic solar applications. Stringent design criteria, i. e., compactness, high performance and safe operation, are targeted by adopting a multi-objective optimization approach modeled with the genetic algorithm. Design-point thermodynamic variables, e. g., evaporating pressure, the working fluid, minimum allowable temperature differences, and the equipment geometry, are the decision variables. Flat plate heat exchangers with herringbone corrugations are selected as heat transfer equipment for the preheater, the evaporator and the condenser. The results unveil the hyperbolic trend binding the net power output to the heat exchanger compactness. Findings also suggest that the evaporator and condenser minimum allowable temperature differences have the largest impact on the system volume and on the cycle performances. Among the fluids considered, the results indicate that R1234yf and R1234ze are the best working fluid candidates. Using flat plate solar collectors (hot water temperature equal to 75 °C, R1234yf is the optimal solution. The heat exchanger volume ranges between 6.0 and 23.0 dm3, whereas the thermal efficiency is around 4.5%. R1234ze is the best working fluid employing parabolic solar collectors (hot water temperature equal to 120 °C. In such case the thermal efficiency is around 6.9%, and the heat exchanger volume varies from 6.0 to 18.0 dm3.

  12. Supercritical Fluid Parameters in Organic Rankine Cycle Applications

    Directory of Open Access Journals (Sweden)

    Andreas Schuster

    2008-09-01

    Full Text Available Nowadays, the use of Organic Rankine Cycle (ORC in decentralised applications is linked with the fact that this process allows to use low temperature heat sources and offers an advantageous efficiency in small-scale applications. Many state of the art applications like geothermal and biomass fired power plants as well as new applications like solar desalination with reverse osmosis, waste heat recovery from biogas digestion plants or micro-Combined Heat and Power (micro-CHP systems can successfully use the ORC process. The investigation of supercritical parameters in ORC applications seems to bring promising results in decentralised energy production. This paper presents the results from the simulation of the ORC process in normal and supercritical fluid parameters and discusses the efficiency variation in various applications.

  13. Experimental investigation of scroll based organic Rankine cycles

    Energy Technology Data Exchange (ETDEWEB)

    Tarique, Md Ali; Dincer, I.; Zamfirescu, C. [Faculty of Engineering and Applied Science, University of Ontario Institute of Technology (Canada)], E-mail: Md.Ali.Tarique@uoit.ca, email: Ibrahim.Dincer@uoit.ca, email: Calin.Zamfirescu@uoit.ca

    2011-07-01

    Global awareness of the greenhouse effect and global warming due to carbon- based fuel combustion has spurred interest in the use of low-grade heat that is abundantly available from renewable energy sources and also from the waste heat produced at plants. This paper investigates the performance of a scroll expander in an Organic Rankine Cycle (ORC), experimentally and analytically, with the purpose of using low-grade sustainable energy sources in mind. The expander was modeled on the basis of thermodynamic and fluid flow characteristics within a control volume boundary and the isentropic efficiency of the expander, which is an important factor in optimizing its performance, was determined. From the experimental analysis, the maximum isentropic efficiency was found to be 66% at 120C source temperature. This shows that mechanical work or electricity can be generated using a scroll expander in a low power ORC. Moreover, the analytical model is validated with regard to the optimal expansion.

  14. Energy analysis of Organic Rankine Cycles for biomass applications

    Directory of Open Access Journals (Sweden)

    Algieri Angelo

    2015-01-01

    Full Text Available The present paper aims at analysing the performances of Organic Rankine Cycles (ORCs adopted for the exploitation of the biomass resulting from the pruning residues in a 3000 hectares district in Southern Italy. A parametric energy analysis has been carried out to define the influence of the main plant operating conditions. To this purpose, both subcritical and transcritical power plants have been examined and saturated and superheated conditions at the turbine inlet have been imposed. Moreover, the effect of the working fluid, condensation temperature, and internal regeneration on system performances has been investigated. The results show that ORC plants represent an interesting and sustainable solution for decentralised and small-scale power production. Furthermore, the analysis highlights the significant impact of the maximum temperature and the noticeable effect of internal regeneration on the performances of the biomass power plants.

  15. Development of a Direct Evaporator for the Organic Rankine Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Donna Post Guillen; Helge Klockow; Matthew Lehar; Sebastian Freund; Jennifer Jackson

    2011-02-01

    This paper describes research and development currently underway to place the evaporator of an Organic Rankine Cycle (ORC) system directly in the path of a hot exhaust stream produced by a gas turbine engine. The main goal of this research effort is to improve cycle efficiency and cost by eliminating the usual secondary heat transfer loop. The project’s technical objective is to eliminate the pumps, heat exchangers and all other added cost and complexity of the secondary loop by developing an evaporator that resides in the waste heat stream, yet virtually eliminates the risk of a working fluid leakage into the gaseous exhaust stream. The research team comprised of Idaho National Laboratory and General Electric Company engineers leverages previous research in advanced ORC technology to develop a new direct evaporator design that will reduce the ORC system cost by up to 15%, enabling the rapid adoption of ORCs for waste heat recovery.

  16. Design and optimization of a novel organic Rankine cycle with improved boiling process

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Larsen, U.; Knudsen, Thomas;

    2015-01-01

    In this paper we present a novel organic Rankine cycle layout, named the organic split-cycle, designed for utilization of low grade heat. The cycle is developed by implementing a simplified version of the split evaporation concept from the Kalina split-cycle in the organic Rankine cycle in order...

  17. Combined Turbine and Cycle Optimization for Organic Rankine Cycle Power Systems—Part B: Application on a Case Study

    Directory of Open Access Journals (Sweden)

    Angelo La Seta

    2016-05-01

    Full Text Available Organic Rankine cycle (ORC power systems have recently emerged as promising solutions for waste heat recovery in low- and medium-size power plants. Their performance and economic feasibility strongly depend on the expander. The design process and efficiency estimation are particularly challenging due to the peculiar physical properties of the working fluid and the gas-dynamic phenomena occurring in the machine. Unlike steam Rankine and Brayton engines, organic Rankine cycle expanders combine small enthalpy drops with large expansion ratios. These features yield turbine designs with few highly-loaded stages in supersonic flow regimes. Part A of this two-part paper has presented the implementation and validation of the simulation tool TURAX, which provides the optimal preliminary design of single-stage axial-flow turbines. The authors have also presented a sensitivity analysis on the decision variables affecting the turbine design. Part B of this two-part paper presents the first application of a design method where the thermodynamic cycle optimization is combined with calculations of the maximum expander performance using the mean-line design tool described in part A. The high computational cost of the turbine optimization is tackled by building a model which gives the optimal preliminary design of an axial-flow turbine as a function of the cycle conditions. This allows for estimating the optimal expander performance for each operating condition of interest. The test case is the preliminary design of an organic Rankine cycle turbogenerator to increase the overall energy efficiency of an offshore platform. For an increase in expander pressure ratio from 10 to 35, the results indicate up to 10% point reduction in expander performance. This corresponds to a relative reduction in net power output of 8.3% compared to the case when the turbine efficiency is assumed to be 80%. This work also demonstrates that this approach can support the plant designer

  18. Performance analysis of organic Rankine cycles using different working fluids

    Directory of Open Access Journals (Sweden)

    Zhu Qidi

    2015-01-01

    Full Text Available Low-grade heat from renewable or waste energy sources can be effectively recovered to generate power by an organic Rankine cycle (ORC in which the working fluid has an important impact on its performance. The thermodynamic processes of ORCs using different types of organic fluids were analyzed in this paper. The relationships between the ORC’s performance parameters (including evaporation pressure, condensing pressure, outlet temperature of hot fluid, net power, thermal efficiency, exergy efficiency, total cycle irreversible loss, and total heat-recovery efficiency and the critical temperatures of organic fluids were established based on the property of the hot fluid through the evaporator in a specific working condition, and then were verified at varied evaporation temperatures and inlet temperatures of the hot fluid. Here we find that the performance parameters vary monotonically with the critical temperatures of organic fluids. The values of the performance parameters of the ORC using wet fluids are distributed more dispersedly with the critical temperatures, compared with those of using dry/isentropic fluids. The inlet temperature of the hot fluid affects the relative distribution of the exergy efficiency, whereas the evaporation temperature only has an impact on the performance parameters using wet fluid.

  19. Analysis of Low Temperature Organic Rankine Cycles for Solar Applications

    Science.gov (United States)

    Li, Yunfei

    The present work focuses on Organic Rankine Cycle (ORC) systems and their application to low temperature waste heat recovery, combined heat and power as well as off-grid solar power generation applications. As CO_2 issues come to the fore front and fossil fuels become more expensive, interest in low grade heat recovery has grown dramatically in the past few years. Solar energy, as a clean, renewable, pollution-free and sustainable energy has great potential for the use of ORC systems. Several ORC solutions have been proposed to generate electricity from low temperature sources. The ORC systems discussed here can be applied to fields such as solar thermal, biological waste heat, engine exhaust gases, small-scale cogeneration, domestic boilers, etc. The current work presents a thermodynamic and economic analysis for the use of ORC systems to convert solar energy or low exergy energy to generate electrical power. The organic working fluids investigated here were selected to investigate the effect of the fluid saturation temperature on the performance of ORCs. The working fluids under investigation are R113, R245fa, R123, with boiling points between 40°C and 200°C at pressures from 10 kPa to 10 MPa. Ambient temperature air at 20oC to 30oC is utilized as cooling resource, and allowing for a temperature difference 10°C for effective heat transfer. Consequently, the working fluids are condensed at 40°C. A combined first- and second-law analysis is performed by varying some system independent parameters at various reference temperatures. The present work shows that ORC systems can be viable and economical for the applications such as waste heat use and off-grid power generation even though they are likely to be more expensive than grid power.

  20. Analysis of hot spots in boilers of organic Rankine cycle units during transient operation

    DEFF Research Database (Denmark)

    Benato, A.; Kærn, Martin Ryhl; Pierobon, Leonardo

    2015-01-01

    This paper is devoted to the investigation of critical dynamic events causing thermochemical decompositionof the working fluid in organic Rankine cycle power systems. The case study is the plant of an oiland gas platform where one of the three gas turbines is combined with an organic Rankine cycle...... and fluid decomposition. It is demonstrated thatthe use of a spray attemperator can mitigate the problems of local overheating of the organic compound.As a practical consequence, this paper provides guidelines for safe and reliable operation of organicRankine cycle power modules on offshore installations....

  1. Design and optimization of a novel organic Rankine cycle with improved boiling process

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Larsen, U.; Knudsen, Thomas

    2015-01-01

    In this paper we present a novel organic Rankine cycle layout, named the organic split-cycle, designed for utilization of low grade heat. The cycle is developed by implementing a simplified version of the split evaporation concept from the Kalina split-cycle in the organic Rankine cycle in order....../pentane mixture which, for the 90 °C hot fluid inlet temperature case, achieves a 14.5% higher net power output than an optimized organic Rankine cycle using the same mixture. Two parameter studies suggest that optimum conditions for the organic split-cycle are when the temperature profile allows the minimum...... pinch point temperature difference to be reached at two locations in the boiler. Compared to the transcritical organic Rankine cycle, the organic split-cycle improves the boiling process without an entailing increase in the boiler pressure, thus enabling an efficient low grade heat to power conversion...

  2. Recent research trends in organic Rankine cycle technology: A bibliometric approach

    DEFF Research Database (Denmark)

    Imran, Muhammad; Haglind, Fredrik; Asim, Muhammad

    2018-01-01

    This work describes the contribution of researchers around the world in the field of the organic Rankine cycle in the period 2000–2016. A bibliometric approach was applied to analyze the scientific publications in the field using the Scopus Elsevier database, together with Science Citation Index...... of active countries, institutes, authors, and journals in the organic Rankine cycle technology field. From 2000 to 2016, there were 2120 articles published by 3443 authors from 997 research institutes scattered over 71 countries. The total number of citations and impact factor are 36,739 and 4597...... are the leading countries in organic Rankine cycle research and account for 64% of the total number of publications. The core research activities in the field are mainly focused on applications of the organic Rankine cycle technology, working fluids selection/performance, cycle architecture, and design...

  3. Analysis of hot spots in boilers of organic Rankine cycle units during transient operation

    DEFF Research Database (Denmark)

    Benato, A.; Kærn, Martin Ryhl; Pierobon, Leonardo;

    2015-01-01

    for single- and two-phase heat transfer coefficients.The results indicate that severe load changes (0.4–1.0 MWs-1) can lead to exceedance of thetemperature limit of fluid decomposition for a period of 10 min. Ramp rates lower than 0.3MWs-1 areacceptable considering the stability of the electric grid......This paper is devoted to the investigation of critical dynamic events causing thermochemical decompositionof the working fluid in organic Rankine cycle power systems. The case study is the plant of an oiland gas platform where one of the three gas turbines is combined with an organic Rankine cycle...... and fluid decomposition. It is demonstrated thatthe use of a spray attemperator can mitigate the problems of local overheating of the organic compound.As a practical consequence, this paper provides guidelines for safe and reliable operation of organicRankine cycle power modules on offshore installations....

  4. Analysis of hot spots in boilers of organic Rankine cycle units during transient operation

    DEFF Research Database (Denmark)

    Benato, A.; Kærn, Martin Ryhl; Pierobon, Leonardo

    2015-01-01

    This paper is devoted to the investigation of critical dynamic events causing thermochemical decompositionof the working fluid in organic Rankine cycle power systems. The case study is the plant of an oiland gas platform where one of the three gas turbines is combined with an organic Rankine cycle...... unit toincrease the overall energy conversion efficiency.The dynamic model of the plant is coupled with a one-dimensional model of the once-through boilerfed by the exhaust thermal power of the gas turbine. The heat exchanger model uses a distributedcross-flow physical topology and local correlations...... and fluid decomposition. It is demonstrated thatthe use of a spray attemperator can mitigate the problems of local overheating of the organic compound.As a practical consequence, this paper provides guidelines for safe and reliable operation of organicRankine cycle power modules on offshore installations....

  5. Optimization of organic Rankine cycle power systems considering multistage axial turbine design

    DEFF Research Database (Denmark)

    Meroni, Andrea; Andreasen, Jesper Graa; Persico, Giacomo

    2017-01-01

    Organic Rankine cycle power systems represent a viable and efficient solution for the exploitation of medium-to-low temperature heat sources. Despite the large number of commissioned units, there is limited literature on the design and optimization of organic Rankine cycle power systems considering...... multistage turbine design. This work presents a preliminary design methodology and working fluid selection for organic Rankine cycle units featuring multistage axial turbines. The method is then applied to the case of waste heat recovery from a large marine diesel engine. A multistage axial turbine model...... is presented and validated with the best available data from literature. The methodology allows the identification of the most suitable working fluid considering the trade-off between cycle and multistage turbine designs. The results of the optimization of cycle and turbine suggest that the fluid n...

  6. Equation of State Selection for Organic Rankine Cycle Modeling Under Uncertainty

    DEFF Research Database (Denmark)

    Frutiger, Jerome; O'Connell, John; Abildskov, Jens

    In recent years there has been a great interest in the design and selection of working fluids for low-temperature Organic Rankine Cycles (ORC), to efficiently produce electrical power from waste heat from chemical engineering applications, as well as from renewable energy sources such as biomass...... cycle, all influence the model output uncertainty. The procedure is highlighted for an ORC for with a low-temperature heat source from exhaust gas from a marine diesel engine.[1] Saleh B, Koglbauer G, Wendland M, Fischer J. Working fluids for lowtemperature organic Rankine cycles. Energy 2007......;32:1210–21.[2] Frutiger J, Andreasen JG, Liu W, Spliethoff H, Haglind F, Abildskov J, Sin G. Working fluid selection for organic Rankine cycles - impact of uncertainty of fluid properties. Energy (accepted s.t. revision)....

  7. Combined Turbine and Cycle Optimization for Organic Rankine Cycle Power Systems—Part A

    DEFF Research Database (Denmark)

    Meroni, Andrea; La Seta, Angelo; Andreasen, Jesper Graa

    2016-01-01

    Axial-flow turbines represent a well-established technology for a wide variety of power generation systems. Compactness, flexibility, reliability and high efficiency have been key factors for the extensive use of axial turbines in conventional power plants and, in the last decades, in organic...... Rankine cycle power systems. In this two-part paper, an overall cycle model and a model of an axial turbine were combined in order to provide a comprehensive preliminary design of the organic Rankine cycle unit, taking into account both cycle and turbine optimal designs. Part A presents the preliminary...

  8. Combined Turbine and Cycle Optimization for Organic Rankine Cycle Power Systems—Part B

    DEFF Research Database (Denmark)

    La Seta, Angelo; Meroni, Andrea; Andreasen, Jesper Graa

    2016-01-01

    Organic Rankine cycle (ORC) power systems have recently emerged as promising solutions for waste heat recovery in low- and medium-size power plants. Their performance and economic feasibility strongly depend on the expander. The design process and efficiency estimation are particularly challenging...... power output of 8.3% compared to the case when the turbine efficiency is assumed to be 80%. This work also demonstrates that this approach can support the plant designer in the selection of the optimal size of the organic Rankine cycle unit when multiple exhaust gas streams are available....

  9. Application of unscented Kalman filter for condition monitoring of an organic Rankine cycle turbogenerator

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Schlanbusch, Rune; Kandepu, Rambabu

    2014-01-01

    for this project. Considering the plant dynamics, it is of paramount importance to monitor the peak temperatures within the once-through boiler serving the bottoming unit to prevent the decomposition of the working fluid. This paper accordingly aims at applying the unscented Kalman filter to estimate...... the temperature distribution inside the primary heat exchanger by engaging a detailed and distributed model of the system and available measurements. Simulation results prove the robustness of the unscented Kalman filter with respect to process noise, measurement disturbances and initial conditions....

  10. Sizing models and performance analysis of waste heat recovery organic Rankine cycles for heavy duty trucks

    OpenAIRE

    Guillaume, Ludovic; Legros, Arnaud; Quoilin, Sylvain; Declaye, Sébastien; Lemort, Vincent

    2013-01-01

    This paper attempts to address this problematic of selecting the architecture, the expander and the working fluid for a waste heat recovery organic (or non-organic) Rankine cycle on a truck engine. It focuses especially on three expander technologies: the scroll, the piston and the screw expanders, and three working fluids: R245fa, ethanol and water. Peer reviewed

  11. Uncertainty Assessment of Equations of State with Application to an Organic Rankine Cycle

    DEFF Research Database (Denmark)

    Frutiger, Jerome; Bell, Ian; O’Connell, John P.

    2017-01-01

    –Redlich–Kwong (SRK), the Peng-Robinson (PR) cubic EoS, and the perturbed-chain statistical associating fluid theory (PCSAFT) EoS, as applied to an organic Rankine cycle (ORC) power system to recover heat from the exhaust gas of a marine diesel engine with cyclopentane as the working fluid. Uncertainties of the Eo...

  12. Organic Rankine cycle unit for waste heat recovery on ships (PilotORC)

    DEFF Research Database (Denmark)

    Haglind, Fredrik; Montagud, Maria E. Mondejar; Andreasen, Jesper Graa

    The project PilotORC was aimed at evaluating the technical and economic feasibility of the use of organic Rankine cycle (ORC) units to recover low-temperature waste heat sources (i.e. exhaust gases, scavenge air, engine cooling system, and lubricant oil system) on container vessels. The project...

  13. A thermodynamic study of waste heat recovery from GT-MHR using organic Rankine cycles

    Science.gov (United States)

    Yari, Mortaza; Mahmoudi, S. M. S.

    2011-02-01

    This paper presents an investigation on the utilization of waste heat from a gas turbine-modular helium reactor (GT-MHR) using different arrangements of organic Rankine cycles (ORCs) for power production. The considered organic Rankine cycles were: simple organic Rankine cycle (SORC), ORC with internal heat exchanger (HORC) and regenerative organic Rankine cycle (RORC). The performances of the combined cycles were studied from the point of view of first and second-laws of thermodynamics. Individual models were developed for each component and the effects of some important parameters such as compressor pressure ratio, turbine inlet temperature, and evaporator and environment temperatures on the efficiencies and on the exergy destruction rate were studied. Finally the combined cycles were optimized thermodynamically using the EES (Engineering Equation Solver) software. Based on the identical operating conditions for the GT-MHR cycle, a comparison between the three combined cycles and a simple GT-MHR cycle is also were made. This comparison was also carried out from the point of view of economics. The GT-MHR/SORC combined cycle proved to be the best among all the cycles from the point of view of both thermodynamics and economics. The efficiency of this cycle was about 10% higher than that of GT-MHR alone.

  14. Study and Design of Waste Heat Recovery using Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Seyed Saied Homami

    2016-03-01

    Full Text Available Existing energy crisis in the world has diverted human perspective to the optimum usage of the available energy resources. One of these solutions is waste heat recovery systems[1]. Simultaneous production of fresh water, power and cooling from waste heat improves energy efficiency in industrial applications which could be operated by organic Rankine cycles. In this article, cogeneration of electricity and heat (CHP in the petrochemical industry, textile and paper production has been reviewed and the usage of aforesaid cycle in these industries is determined. Designing organic Rankine cycle (with operating fluid organic trans-butene and taking advantage of the excess low pressure steam, a strategy for producing three valuable products of fresh water, power and refrigeration in the petrochemical industries has been offered. Simultaneous production of 10,000 kg/hr fresh water, 1533 kw power and access to the lower temperatures of about 226 K and 260 K were resulted.

  15. Studi Variasi Flowrate Refrigerant pada Sistem Organic Rankine Cycle dengan Fluida Kerja R-123

    Directory of Open Access Journals (Sweden)

    Aria Halim Pamungkas

    2013-09-01

    Full Text Available Saat ini kelangkaan sumber energi fosil telah menjadi isu utama di seluruh dunia. Hal tersebut memberikan dampak yang signifikan di setiap aspek kehidupan dan salah satunya adalah di bidang pembangkit listrik. Salah satu sistem pembangkit listrik yang tidak menggunakan energi fosil adalah Organic rankine cycle (ORC. Pada penelitian ini dilakukan dengan metode eksperimental pada suatu sistem Organic rankine cycle yang telah dibangun. Penelitian ini yang divariasikan adalah flowrate dari fluida kerja dalam hal ini R-123. Variasi flowrate yang digunakan yaitu 3-1 GPM (Galon per menit dengan penurunan 0,5 GPM setiap pengambilan data. Hasil yang didapatkan dari penelitian ini berupa grafik–grafik daya pada turbin, kondensor, pompa dan evaporator, efisiensi siklus dan back work ratio  fungsi flowrate fluida kerja. Efisiensi siklus tertinggi adalah 5,86% yang terjadi pada flowrate 3 GPM dan efisiensi siklus terendah adalah 4,32% yang terjadi pada flowrate 1 GPM.

  16. Dynamic test on waste heat recovery system with organic Rankine cycle

    Institute of Scientific and Technical Information of China (English)

    王志奇; 刘力文; 夏小霞; 周乃君

    2014-01-01

    Dynamic performance is important to the controlling and monitoring of the organic Rankine cycle(ORC) system so to avoid the occurrence of unwanted conditions. A small scale waste heat recovery system with organic Rankine cycle was constructed and the dynamic behavior was presented. In the dynamic test, the pump was stopped and then started. In addition, there was a step change of the flue gas volume flow rate and the converter frequency of multistage pump, respectively. The results indicate that the working fluid flow rate has the shortest response time, followed by the expander inlet pressure and the expander inlet temperature. The operation frequency of pump is a key parameter for the ORC system. Due to a step change of pump frequency (39.49−35.24 Hz), the expander efficiency and thermal efficiency drop by 16%and 21%within 2 min, respectively. Besides, the saturated mixture can lead to an increase of the expander rotation speed.

  17. Organic rankine cycle with positive displacement expander and variable working fluid composition

    OpenAIRE

    2016-01-01

    Organic Rankine Cycles are often used in the exploitation of low-temperature heat sources. The relatively small temperature differential available to these projects makes them particularly vulnerable to changing ambient conditions, especially if an air-cooled condenser is used. The authors have recently demonstrated that a dynamic ORC with a variable working fluid composition, tuned to match the condensing temperature with the heat sink, can be used to achieve a considerable increase in year-...

  18. Linear Active Disturbance Rejection Control of Waste Heat Recovery Systems with Organic Rankine Cycles

    OpenAIRE

    Fang Fang; Hong Yue; Yeli Zhou; Jiancun Feng; Jianhua Zhang

    2012-01-01

    In this paper, a linear active disturbance rejection controller is proposed for a waste heat recovery system using an organic Rankine cycle process, whose model is obtained by applying the system identification technique. The disturbances imposed on the waste heat recovery system are estimated through an extended linear state observer and then compensated by a linear feedback control strategy. The proposed control strategy is applied to a 100 kW waste heat recovery system to handle the power ...

  19. Comparison of Organic Rankine Cycle Under Varying Conditions Using Turbine and Twin-Screw Expanders

    OpenAIRE

    Read, M. G.; Smith, I K; Stosic, N.

    2015-01-01

    A multi-variable optimization program has been developed to investigate the performance of Organic Rankine Cycles (ORCs) for low temperature heat recovery applications. This cycle model contains detailed thermodynamic models of the system components, and the methods used to match the operation of the expander to the requirements of the cycle are described. Two types of ORC system are considered; one containing a turbine to expand dry saturated or superheated vapour, and one with a twin-screw ...

  20. Comparison of organic rankine cycle systems under varying conditions using turbine and twin-screw expanders

    OpenAIRE

    Read, M. G.; Smith, I K; Stosic, N.; Kovacevic, A.

    2016-01-01

    A multi-variable optimization program has been developed to investigate the performance of Organic Rankine Cycles (ORCs) for low temperature heat recovery applications using both turbine and twin-screw expanders when account is taken of performance variation due to changes in ambient conditions. The cycle simulation contains thermodynamic models of both types of expander. In the case of the twin-screw machine, the methods used to match the operation of the expander to the requirements of the ...

  1. Performance analysis of a solar-powered organic rankine cycle engine.

    Science.gov (United States)

    Bryszewska-Mazurek, Anna; Swieboda, Tymoteusz; Mazurek, Wojciech

    2011-01-01

    This paper presents the performance analysis of a power plant with the Organic Rankine Cycle (ORC). The power plant is supplied by thermal energy utilized from a solar energy collector. R245fa was the working fluid in the thermodynamic cycle. The organic cycle with heat regeneration was built and tested experimentally. The ORC with a heat regenerator obtained the maximum thermodynamic efficiency of approximately 9%.

  2. THERMODYNAMIC ANALYSIS OF DIFFERENT WORKING FLUIDS USED IN ORGANIC RANKINE CYCLE FOR RECOVERING WASTE HEAT FROM GT-MHR

    National Research Council Canada - National Science Library

    AMIN HABIBZADEH; MOHAMMAD MEHDI RASHIDI

    2016-01-01

    In this paper, the performance of 13 working fluids in two Organic Rankine Cycles, which operate as the bottoming cycles for recovering waste heat from gas turbine modular helium reactor (GT-MHR), is investigated...

  3. Working fluid selection for organic Rankine cycles - Impact of uncertainty of fluid properties

    DEFF Research Database (Denmark)

    Frutiger, Jerome; Andreasen, Jesper Graa; Liu, Wei

    2016-01-01

    of processmodels and constraints 2) selection of property models, i.e. Penge Robinson equation of state 3)screening of 1965 possible working fluid candidates including identification of optimal process parametersbased on Monte Carlo sampling 4) propagating uncertainty of fluid parameters to the ORC netpower output......This study presents a generic methodology to select working fluids for ORC (Organic Rankine Cycles)taking into account property uncertainties of the working fluids. A Monte Carlo procedure is described as a tool to propagate the influence of the input uncertainty of the fluid parameters on the ORC...

  4. Analysis of the Properties of Working Substances for the Organic Rankine Cycle based Database "REFPROP"

    Science.gov (United States)

    Galashov, Nikolay; Tsibulskiy, Svyatoslav; Serova, Tatiana

    2016-02-01

    The object of the study are substances that are used as a working fluid in systems operating on the basis of an organic Rankine cycle. The purpose of research is to find substances with the best thermodynamic, thermal and environmental properties. Research conducted on the basis of the analysis of thermodynamic and thermal properties of substances from the base "REFPROP" and with the help of numerical simulation of combined-cycle plant utilization triple cycle, where the lower cycle is an organic Rankine cycle. Base "REFPROP" describes and allows to calculate the thermodynamic and thermophysical parameters of most of the main substances used in production processes. On the basis of scientific publications on the use of working fluids in an organic Rankine cycle analysis were selected ozone-friendly low-boiling substances: ammonia, butane, pentane and Freon: R134a, R152a, R236fa and R245fa. For these substances have been identified and tabulated molecular weight, temperature of the triple point, boiling point, at atmospheric pressure, the parameters of the critical point, the value of the derivative of the temperature on the entropy of the saturated vapor line and the potential ozone depletion and global warming. It was also identified and tabulated thermodynamic and thermophysical parameters of the steam and liquid substances in a state of saturation at a temperature of 15 °C. This temperature is adopted as the minimum temperature of heat removal in the Rankine cycle when working on the water. Studies have shown that the best thermodynamic, thermal and environmental properties of the considered substances are pentane, butane and R245fa. For a more thorough analysis based on a gas turbine plant NK-36ST it has developed a mathematical model of combined cycle gas turbine (CCGT) triple cycle, where the lower cycle is an organic Rankine cycle, and is used as the air cooler condenser. Air condenser allows stating material at a temperature below 0 °C. Calculation of the

  5. Multi-objective optimization of organic Rankine cycle power plants using pure and mixed working fluids

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Kærn, Martin Ryhl; Pierobon, Leonardo

    2015-01-01

    For zeotropic mixtures, the temperature varies during phase change, which is opposed to the isothermalphase change of pure fluids. The use of such mixtures as working fluids in organic Rankine cyclepower plants enables a minimization of the mean temperature difference of the heat exchangers whenthe......-objectiveoptimization of the net power output and the component costs for organic Rankine cycle power plantsusing low-temperature heat at 90 C to produce electrical power at around 500 kW. The primary outcomesof the study are Pareto fronts, illustrating the power/cost relations for R32, R134a and R32/R134a(0.65/0.35mole...

  6. FLUOROETHERS AS A WORKING FLUIDS FOR LOW TEMPERATURE ORGANIC RANKINE CYCLE

    Directory of Open Access Journals (Sweden)

    Artemenko S.V

    2014-12-01

    Full Text Available Hydrofluoroethers as a new class of working fluids for the organic Rankine cycle have been considered to utilize the low-potential waste heat. Temperature range 300…400 K was chosen to provide energy conversion of waste heat from fuel cells. The direct assessment of the efficiency criteria for the Rankine cycle via artificial neural networks (ANN was used. To create ANN the critical parameters of substance and normal boiling temperature as input were chosen. The forecast of efficiency criteria for the Rankine cycle as output parameter which reproduces the coefficient of performance with high accuracy and without thermodynamic property calculations was presented.

  7. A Novel Organic Rankine Cycle System with Improved Thermal Stability and Low Global Warming Fluids

    Directory of Open Access Journals (Sweden)

    Panesar Angad S

    2014-07-01

    Full Text Available This paper proposes a novel Organic Rankine Cycle (ORC system for long haul truck application. Rather than typical tail pipe heat recovery configurations, the proposed setup exploits the gaseous streams that are already a load on the engine cooling module. The system uses dual loops connected only by the Exhaust Gas Recirculation (EGR stream. A water blend study is conducted to identify suitable mixtures for the High Temperature (HT loop, while the Low Temperature (LT loop utilises a Low Global Warming (GWP Hydrofluoroether.

  8. Performance analysis of different organic Rankine cycle configurations on board liquefied natural gas-fuelled vessels

    DEFF Research Database (Denmark)

    Baldasso, Enrico; Andreasen, Jesper Graa; Meroni, Andrea

    2017-01-01

    Gas-fuelled shipping is expected to increase significantly in the coming years. Similarly, much effort is devoted to the study of waste heat recovery systems to be implemented on board ships. In this context, the organic Rankine cycle (ORC) technology is considered one of the most promising...... solutions. The ORC favorably compares to the steam Rankine cycle because of its simple layout and high efficiency, achievable by selecting a working fluid with desirable properties. This paper aims at assessing the fuel savings attainable by implementing ORC units on board vessels powered by liquefied...

  9. Multi-Variable Optimisation Of Wet Vapour Organic Rankine Cycles With Twin-Screw Expanders

    OpenAIRE

    2014-01-01

    A multi-variable optimisation program has been developed to investigate the performance of Wet Organic Rankine Cycles for low temperature heat recovery applications. This cycle model contains a detailed thermodynamic model of the twin-screw expander, and the methods used to match the operation of the expander to the requirements of the cycle are described. The capability of the cycle model has been demonstrated for the case of heat recovery from a source of pressurized hot water at 120°C. The...

  10. Multi-Objective Optimization of Organic Rankine Cycle Power Plants Using Pure and Mixed Working Fluids

    Directory of Open Access Journals (Sweden)

    Jesper G. Andreasen

    2016-04-01

    Full Text Available For zeotropic mixtures, the temperature varies during phase change, which is opposed to the isothermal phase change of pure fluids. The use of such mixtures as working fluids in organic Rankine cycle power plants enables a minimization of the mean temperature difference of the heat exchangers, which is beneficial for cycle performance. On the other hand, larger heat transfer surface areas are typically required for evaporation and condensation when zeotropic mixtures are used as working fluids. In order to assess the feasibility of using zeotropic mixtures, it is, therefore, important to consider the additional costs of the heat exchangers. In this study, we aim at evaluating the economic feasibility of zeotropic mixtures compared to pure fluids. We carry out a multi-objective optimization of the net power output and the component costs for organic Rankine cycle power plants using low-temperature heat at 90 ∘ C to produce electrical power at around 500 kW. The primary outcomes of the study are Pareto fronts, illustrating the power/cost relations for R32, R134a and R32/R134a (0.65/0.35 mole . The results indicate that R32/R134a is the best of these fluids, with 3.4 % higher net power than R32 at the same total cost of 1200 k$.

  11. Research of efficiency of the organic Rankine cycle on a mathematical model

    Directory of Open Access Journals (Sweden)

    Galashov N.

    2017-01-01

    Full Text Available The object of the study are the organic Rankine cycle. The purpose of research is to evaluate the impact on the net efficiency of the initial and final properties of the cycle at work on a saturated and superheated steam. Investigations were carried out on the basis of a mathematical model, in which the thermodynamic properties of materials are determined on the basis of “REFPROP”. On the basis of the available scientific publications on the use of working fluids in an organic Rankine cycle analysis was selected ozone-safe pentane. A mathematical model has been developed on condition that condenser is used as air cooler which allows the substance to condense at a temperature below 0 °С. Numerical study on the mathematical model shown that net efficiency at work on pentane linearly depends on the condensation temperature and parabolically depends on the initial temperature with the saturated steam. During work at the superheated steam efficiency strongly depends on both the initial temperature and of the initial pressure. With rising initial temperature is necessary to gradually increase the initial pressure under certain conditions.

  12. Multi-Objective Optimization of Organic Rankine Cycle Power Plants Using Pure and Mixed Working Fluids

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Kærn, Martin Ryhl; Pierobon, Leonardo;

    2016-01-01

    For zeotropic mixtures, the temperature varies during phase change, which is opposed to the isothermal phase change of pure fluids. The use of such mixtures as working fluids in organic Rankine cycle power plants enables a minimization of the mean temperature difference of the heat exchangers...... to consider the additional costs of the heat exchangers. In this study, we aim at evaluating the economic feasibility of zeotropic mixtures compared to pure fluids. We carry out a multi-objective optimization of the net power output and the component costs for organic Rankine cycle power plants using low......-temperature heat at 90 ◦C to produce electrical power at around 500 kW. The primary outcomes of the study are Pareto fronts, illustrating the power/cost relations for R32, R134a and R32/R134a (0.65/0.35mole). The results indicate that R32/R134a is the best of these fluids, with 3.4 % higher net power than R32...

  13. A comprehensive study on waste heat recovery from internal combustion engines using organic Rankine cycle

    Directory of Open Access Journals (Sweden)

    Tahani Mojtaba

    2013-01-01

    Full Text Available There are a substantial amount of waste heat through exhaust gas and coolant of an Internal Combustion Engine. Organic Rankine cycle is one of the opportunities in Internal Combustion Engines waste heat recovery. In this study, two different configurations of Organic Rankine cycle with the capability of simultaneous waste heat recovery from exhaust gas and coolant of a 12L diesel engine were introduced: Preheat configuration and Two-stage. First, a parametric optimization process was performed for both configurations considering R-134a, R-123, and R-245fa as the cycle working fluids. The main objective in optimization process was maximization of the power generation and cycle thermal efficiency. Expander inlet pressure and preheating temperature were selected as design parameters. Finally, parameters like hybrid generated power and reduction of fuel consumption were studied for both configurations in different engine speeds and full engine load. It was observed that using R-123 as the working fluid, the best performance in both configurations was obtained and as a result the 11.73% and 13.56% reduction in fuel consumption for both preheat and Two-stage configurations were found respectively.

  14. Waste Heat Recovery of a PEMFC System by Using Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Tianqi He

    2016-04-01

    Full Text Available In this study, two systems are brought forward to recover the waste heat of a proton exchange membrane fuel cell (PEMFC, which are named the organic Rankine cycle (ORC, and heat pump (HP combined organic Rankine cycle (HPORC. The performances of both systems are simulated on the platform of MATLAB with R123, R245fa, R134a, water, and ethanol being selected as the working fluid, respectively. The results show that, for PEMFC where operating temperature is constantly kept at 60 °C, there exists an optimum working temperature for each fluid in ORC and HPORC. In ORC, the maximal net power can be achieved with R245fa being selected as the working fluid. The corresponding thermal efficiency of the recovery system is 4.03%. In HPORC, the maximal net power can be achieved with water being selected in HP and R123 in ORC. The thermal efficiency of the recovery system increases to 4.73%. Moreover, the possibility of using ORC as the cooling system of PEMFC is also studied. The heat released from PEMFC stack is assumed to be wholly recovered by the ORC or HPORC system. The results indicate that the HPORC system is much more feasible for the cooling system of a PEMFC stack, since the heat recovery ability can be promoted due to the presence of HP.

  15. Thermodynamic performance analysis of a coupled transcritical and subcritical organic Rankine cycle system for waste heat recovery

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Xi Wu [Zhejiang Ocean University, Zhejian (China); Wang, Xiao Qiong; Li, You Rong; Wu, Chun Mei [Chongqing University, Chongqing (China)

    2015-07-15

    We present a novel coupled organic Rankine cycle (CORC) system driven by the low-grade waste heat, which couples a transcritical organic Rankine cycle with a subcritical organic Rankine cycle. Based on classical thermodynamic theory, a detailed performance analysis on the novel CORC system was performed. The results show that the pressure ratio of the expander is decreased in the CORC and the selection of the working fluids becomes more flexible and abundant. With the increase of the pinch point temperature difference of the internal heat exchanger, the net power output and thermal efficiency of the CORC all decrease. With the increase of the critical temperature of the working fluid, the system performance of the CORC is improved. The net power output and thermal efficiency of the CORC with isentropic working fluids are higher than those with dry working fluids.

  16. Regulation Law of Turbine and Generator in Organic Rankine Cycle Power Generation Experimental System

    Institute of Scientific and Technical Information of China (English)

    潘利生; 王怀信; 史维秀

    2014-01-01

    In the performance experiment of organic Rankine cycle power generation experimental system, the load-resistance-regulation method is one of the most important regulation methods. However, the regulation law has not been clear enough to guide the experiment, which is unfavorable to the experimental research on organic Rankine cy-cle. In this paper the regulation law of turbine and generator by the load-resistance-regulation method is studied theo-retically and experimentally. The results show that when the thermal cycle parameters keep constant, the turbine speed increases with the increase of load resistance and there is a maximum value of transmission-generator efficiency with the variation of the turbine speed; when the turbine speed and generator speed keep constant, the transmission-generator efficiency decreases and gradually tends to zero with the increase of load resistance.

  17. Linear Active Disturbance Rejection Control of Waste Heat Recovery Systems with Organic Rankine Cycles

    Directory of Open Access Journals (Sweden)

    Fang Fang

    2012-12-01

    Full Text Available In this paper, a linear active disturbance rejection controller is proposed for a waste heat recovery system using an organic Rankine cycle process, whose model is obtained by applying the system identification technique. The disturbances imposed on the waste heat recovery system are estimated through an extended linear state observer and then compensated by a linear feedback control strategy. The proposed control strategy is applied to a 100 kW waste heat recovery system to handle the power demand variations of grid and process disturbances. The effectiveness of this controller is verified via a simulation study, and the results demonstrate that the proposed strategy can provide satisfactory tracking performance and disturbance rejection.

  18. An Innovative Organic Rankine Cycle wtih Gas-liquid Injector for Pressurization

    Institute of Scientific and Technical Information of China (English)

    ZHU Hua-yun; XU Zhi-ming

    2016-01-01

    The organic Rankine cycle ( ORC ) is an effective way to recycle low temperature exhaust heat but pump for the ORC has several disadvantages such as great difficulty in manufacturing , easily-invited cavitations , low efficiency and high cost .Gas-liquid two-phase injector is a device without moving parts , in which steam is used to drive cold liquid from a pressure lower than the primary steam to a pressure higher than the primary steam.In this paper , the mechanical circulation pump was replaced with a gas-liquid injector .The effect of the evaporate temperature for the system was studied with the organic fluid R 123.While this novel ORC can not only improves the energy utilization , but also be suitable for some occasions without power .

  19. Effectiveness of Operation of Organic Rankine Cycle Installation Applied in the Liquid Natural Gas Regasification Plant

    Science.gov (United States)

    Kaczmarek, R.; Stachel, A. A.

    2017-05-01

    An analysis of the operation of an Organic Rankine Cycle (ORC) installation heated by a low-temperature heat source is presented for the case where a condenser of a working fluid is cooled by a liquid of ultralow temperature. For this purpose, the process of regasification of liquid natural gas (LNG) is considered. In the process, the condensation heat of the working fluid in ORC is taken by the LNG evaporating subsequently (i.e., undergoing regasification). The paper presents the schematic of this installation and its application, as well as the results of calculations on the basis of the analysis in terms of the power and efficiency. In the analysis, organic fluids used in the ORC as working ones have been selected.

  20. Performance analysis a of solar driven organic Rankine cycle using multi-component working fluids

    DEFF Research Database (Denmark)

    Baldasso, E.; Andreasen, J. G.; Modi, A.

    2015-01-01

    Among the different renewable sources of energy, solar power could play a primary role in the development of a more sustainable electricity generation system. While large scale concentrated solar power plants based on the steam Rankine cycle have already been proved to be cost effective, research...... cycle. The purpose of this paper is to optimize a low temperature organic Rankine cycle tailored for solar applications. The objective of the optimization is the maximization of the solar to electrical efficiency and the optimization parameters are the working fluid and the turbine inlet temperature...... is still under progress for small scale low temperature solar-driven power plants. The steam Rankine cycle is suitable for high temperature applications, but its efficiency drastically decreases as the heat source temperature drops. In these cases a much more promising configuration is the organic Rankine...

  1. Experimental Study of a Low-Temperature Power Generation System in an Organic Rankine Cycle

    DEFF Research Database (Denmark)

    Mu, Yongchao; Zhang, Yufeng; Deng, Na

    2015-01-01

    as the engine of the power generator. The style of the preheater was a shell and tube heat exchanger, which could provide a long path for the working fluid. A flooded heat exchanger with a high heat transfer coefficient was taken as the evaporator. R134a was used as working fluid for the Rankine cycle......This paper presents a new power generation system under the principle of organic Rankine cycle which can generate power with a low-temperature heat source. A prototype was built to investigate the proposed system. In the prototype, an air screw compressor was converted into an expander and used...... in the system. This study compared and analyzed the experimental performance of the prototype at different heat source temperatures. The results show that the preheater and flooded evaporator was used for sensible heating and latent heating of the working fluid, respectively, as expected. When the temperature...

  2. Thermal Stability of Hexamethyldisiloxane (MM for High-Temperature Organic Rankine Cycle (ORC

    Directory of Open Access Journals (Sweden)

    Markus Preißinger

    2016-03-01

    Full Text Available The design of efficient Organic Rankine Cycle (ORC units for the usage of industrial waste heat at high temperatures requires direct contact evaporators without intermediate thermal oil circuits. Therefore, the thermal stability of high-temperature working fluids gains importance. In this study, the thermal degradation of hexamethyldisiloxane (MM is investigated in an electrically heated tube. Qualitative results concerning remarks on degradation products as well as quantitative results like the annual degradation rate are presented. It is shown that MM is stable up to a temperature of 300 °C with annual degradation rates of less than 3.5%. Furthermore, the break of a silicon–carbon bond can be a main chemical reaction that influences the thermal degradation. Finally, it is discussed how the results may impact the future design of ORC units.

  3. Organic Rankine-cycle turbine power plant utilizing low temperature heat sources

    Science.gov (United States)

    Maizza, V.

    1980-03-01

    Utilizing and converting of existing low temperature and waste heat sources by the use of a high efficiency bottoming cycle is attractive and should be possible for many locations. This paper presents a theoretical study on possible combination of an organic Rankine-cycle turbine power plate with the heat pump supplied by waste energy sources. Energy requirements and system performances are analyzed using realistic design operating condition for a middle town. Some conversion systems employing working fluids other than water are being studied for the purpose of proposed application. Thermodynamic efficiencies, with respect to available resource, have been calculated by varying some system operating parameters at various reference temperature. With reference to proposed application equations and graphs are presented which interrelate the turbine operational parameters for some possible working fluids with computation results.

  4. Parametric theoretical study of a two-stage solar organic Rankine cycle for RO desalination

    Energy Technology Data Exchange (ETDEWEB)

    Kosmadakis, G.; Manolakos, D.; Papadakis, G. [Department of Natural Resources and Agricultural Engineering, Agricultural University of Athens, 75 Iera Odos Street, 11855 Athens (Greece)

    2010-05-15

    The present work concerns the parametric study of an autonomous, two-stage solar organic Rankine cycle for RO desalination. The main goal of the current simulation is to estimate the efficiency, as well as to calculate the annual mechanical energy available for desalination in the considered cases, in order to evaluate the influence of various parameters on the performance of the system. The parametric study concerns the variation of different parameters, without changing actually the baseline case. The effect of the collectors' slope and the total number of evacuated tube collectors used, have been extensively examined. The total cost is also taken into consideration and is calculated for the different cases examined, along with the specific fresh water cost (EUR/m{sup 3}). (author)

  5. Design of organic Rankine cycle power systems accounting for expander performance

    DEFF Research Database (Denmark)

    La Seta, Angelo; Andreasen, Jesper Graa; Pierobon, Leonardo;

    2015-01-01

    Organic Rankine cycle power systems have recently emerged as promising solutions for waste heat recovery in low- and medium-size power plants. Their performance and economic feasibility strongly depend on the expander. Its design process and efficiency estimation are particularly challenging due......-loaded stages in supersonic flow regimes. This paper proposes a design method where the conventional cycle analysis is combined with calculations of the maximum expander performance using a validated mean-line design tool. The high computational cost of the turbine optimization is tackled building a model which...... efficiency of an offshore platform. The analysis of the results obtained using a constant turbine efficiency and the method proposed in this paper indicates a maximum reduction of the expander performance of 10% points for pressure ratios between 10 and 35. This work also demonstrates that this approach can...

  6. Exergy Analysis of Vapor Compression Cycle Driven by Organic Rankine Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyoung Hoon [Kumoh Nat' l Institute of Technology, Gumi (Korea, Republic of)

    2013-12-15

    In this study, exergy analysis of a thermally activated refrigeration cycle, a combined organic Rankine cycle (ORC), and a vapor compression cycle (VCC) were conducted. It is considered that a system uses a low-temperature heat source in the form of sensible heat, such as various renewable energy sources or waste heat from industries, and one of eight working fluids: R143a, R22, R134a, propane, isobutane, butane, R245fa, or R123. The effects of turbine inlet pressure and the working fluid selected on the exergy destructions (anergies) at various system components as well as the COP and exergy efficiency of the system were analyzed and discussed. The results show that the component of the greatest exergy destruction in the system varies sensitively with the turbine inlet pressure and/or working fluid.

  7. Multi-objective optimization of organic Rankine cycles for waste heat recovery: Application in an offshore platform

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Nguyen, Tuong-Van; Larsen, Ulrik

    2013-01-01

    This paper aims at finding the optimal design of MW-size organic Rankine cycles by employing the multi-objective optimization with the genetic algorithm as the optimizer. We consider three objective functions: thermal efficiency, total volume of the system and net present value. The optimization...... variables are the working fluid, the turbine inlet pressure and temperature, the condensing temperature, the pinch points and the fluid velocities in the heat exchangers. The optimization process also includes the complete design of the shell and tube heat exchangers utilized in the organic Rankine cycle...

  8. Selection and optimization of pure and mixed working fluids for low grade heat utilization using organic Rankine cycles

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Larsen, Ulrik; Knudsen, Thomas

    2014-01-01

    We present a generic methodology for organic Rankine cycle optimization, where the working fluid is included as an optimization parameter, in order to maximize the net power output of the cycle. The method is applied on two optimization cases with hot fluid inlet temperatures at 120°C and 90°C...

  9. Exergetic Analysis of an Integrated Tri-Generation Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Ratha Z. Mathkor

    2015-08-01

    Full Text Available This paper reports on a study of the modelling, validation and analysis of an integrated 1 MW (electrical output tri-generation system energized by solar energy. The impact of local climatic conditions in the Mediterranean region on the system performance was considered. The output of the system that comprised a parabolic trough collector (PTC, an organic Rankine cycle (ORC, single-effect desalination (SED, and single effect LiBr-H2O absorption chiller (ACH was electrical power, distilled water, and refrigerant load. The electrical power was produced by the ORC which used cyclopentane as working fluid and Therminol VP-1 was specified as the heat transfer oil (HTO in the collectors with thermal storage. The absorption chiller and the desalination unit were utilize the waste heat exiting from the steam turbine in the ORC to provide the necessary cooling energy and drinking water respectively. The modelling, which includes an exergetic analysis, focuses on the performance of the solar tri-generation system. The simulation results of the tri-generation system and its subsystems were produced using IPSEpro software and were validated against experimental data which showed good agreement. The tri-generation system was able to produce about 194 Ton of refrigeration, and 234 t/day distilled water.

  10. Combined solar organic Rankine cycle with reverse osmosis desalination process: Energy, exergy, and cost evaluations

    Energy Technology Data Exchange (ETDEWEB)

    Nafey, A.S.; Sharaf, M.A. [Department of Engineering Science, Faculty of Petroleum and Mining Engineering, Suez Canal University, Suez (Egypt)

    2010-11-15

    Organic Rankine cycles (ORC) have unique properties that are well suited to solar power generation. In this work design and performance calculations are performed using MatLab/SimuLink computational environment. The cycle consists of thermal solar collectors (Flat Plate Solar Collector (FPC), or Parabolic Trough Collector (PTC), or Compound Parabolic Concentrator (CPC)) for heat input, expansion turbine for work output, condenser unit for heat rejection, pump unit, and Reverse Osmosis (RO) unit. Reverse osmosis unit specifications used in this work is based on Sharm El-Shiekh RO desalination plant. Different working fluids such as: butane, isobutane, propane, R134a, R152a, R245ca, and R245fa are examined for FPC. R113, R123, hexane, and pentane are investigated for CPC. Dodecane, nonane, octane, and toluene are allocated for PTC. The proposed process units are modeled and show a good validity with literatures. Exergy and cost analysis are performed for saturation and superheated operating conditions. Exergy efficiency, total exergy destruction, thermal efficiency, and specific capital cost are evaluated for direct vapor generation (DVG) process. Toluene and Water achieved minimum results for total solar collector area, specific total cost and the rate of exergy destruction. (author)

  11. Effect of working fluids on organic Rankine cycle for waste heat recovery

    Energy Technology Data Exchange (ETDEWEB)

    Bo Tau Liu; Kuo Hsiang Chien; Chi Chuan Wang [Industrial Technology Research Inst., Hsinchu, Taiwan (China). Energy and Resources Lab.

    2004-06-01

    This study presents an analysis of the performance of organic Rankine cycle (ORC) subjected to the influence of working fluids. The effects of various working fluids on the thermal efficiency and on the total heat-recovery efficiency have been investigated. It is found that the presence of hydrogen bond in certain molecules such as water, ammonia, and ethanol may result in wet fluid conditions due to larger vaporizing enthalpy, and is regarded as inappropriate for ORC systems. The calculated results reveal that the thermal efficiency for various working fluids is a weak function of the critical temperature. The maximum value of the total heat-recovery efficiency occurs at the appropriate evaporating temperature between the inlet temperature of waste heat and the condensing temperature. In addition, the maximum value of total heat-recovery efficiency increases with the increase of the inlet temperature of the waste heat source and decreases it by using working fluids having lower critical temperature. Analytical results using a constant waste heat temperature or based on thermal efficiency may result in considerable deviation of system design relative to the varying temperature conditions of the actual waste heat recovery and is regarded as inappropriate. (author)

  12. An approach for IC engine coolant energy recovery based on low-temperature organic Rankine cycle

    Institute of Scientific and Technical Information of China (English)

    付建勤; 刘敬平; 徐政欣; 邓帮林; 刘琦

    2015-01-01

    To promote the fuel utilization efficiency of IC engine, an approach was proposed for IC engine coolant energy recovery based on low-temperature organic Rankine cycle (ORC). The ORC system uses IC engine coolant as heat source, and it is coupled to the IC engine cooling system. After various kinds of organic working media were compared, R124 was selected as the ORC working medium. According to IC engine operating conditions and coolant energy characteristics, the major parameters of ORC system were preliminary designed. Then, the effects of various parameters on cycle performance and recovery potential of coolant energy were analyzed via cycle process calculation. The results indicate that cycle efficiency is mainly influenced by the working pressure of ORC, while the maximum working pressure is limited by IC engine coolant temperature. At the same working pressure, cycle efficiency is hardly affected by both the mass flow rate and temperature of working medium. When the bottom cycle working pressure arrives at the maximum allowable value of 1.6 MPa, the fuel utilization efficiency of IC engine could be improved by 12.1%. All these demonstrate that this low-temperature ORC is a useful energy-saving technology for IC engine.

  13. Parametric Optimization of Regenerative Organic Rankine Cycle System for Diesel Engine Based on Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Hongjin Wang

    2015-09-01

    Full Text Available To efficiently recover the waste heat from a diesel engine exhaust, a regenerative organic Rankine cycle (RORC system was employed, and butane, R124, R416A, and R134a were used as the working fluids. The resulting diesel engine-RORC combined system was defined and the relevant evaluation indexes were proposed. First, the variation tendency of the exhaust energy rate under various diesel engine operating conditions was analyzed using experimental data. The thermodynamic model of the RORC system was established based on the first and second laws of thermodynamics, and the net power output and exergy destruction rate of the RORC system were selected as the objective functions. A particle swarm optimization (PSO algorithm was used to optimize the operating parameters of the RORC system, including evaporating pressure, intermediate pressure, and degree of superheat. The operating performances of the RORC system and diesel engine-RORC combined system were studied for the four selected working fluids under various operating conditions of the diesel engine. The results show that the operating performances of the RORC system and the combined system using butane are optimal on the basis of optimizing the operating parameters; when the engine speed is 2200 r/min and engine torque is 1215 N·m, the net power output of the RORC system using butane is 36.57 kW, and the power output increasing ratio (POIR of the combined system using butane is 11.56%.

  14. Simulation of an Innovative Stand-Alone Solar Desalination System Using an Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Jürgen Karl

    2007-12-01

    Full Text Available

    The rising of the world’s population leads automatically to the rising of water demand. As a consequence the lack of drinking water increases. Since a large part of the world’s population is concentrated in coastal areas, the desalination of seawater seems to be a promising solution. An innovative stand-alone solar desalination system could be used to produce drinking water from seawater. The great advantage of such a system is that it combines efficient desalination technology, reverse osmosis, with a renewable energy source, solar radiation. Thermal energy produced by the solar array evaporates a working fluid, which is used in an organic Rankine cycle that drives the pumps needed for the reverse osmosis process. Due to the fluctuation of solar irradiation, the dynamic simulation of such a system is necessary in order to assure the sufficient supply of water throughout a year. The simulation provides important information for optimum system sizing and design. The aim of this work is to present a modelling of a solar desalination system and to investigate the impact of different working fluids, thermodynamic parameters and cycle variations on the efficiency and water production of such a system.

    • An initial version of this paper was published in October, 2005 in the proceedings of SIMS'05, Trondheim, Norway. 

  15. A thermodynamics comparison of subcritical and transcritical organic Rankine cycle system for power generation

    Institute of Scientific and Technical Information of China (English)

    朱家玲; 薄华宇; 李太禄; 胡开永; 刘克涛

    2015-01-01

    A comparison on subcritical and transcritical organic Rankine cycle (ORC) system with a heat source of 110 °C geothermal water was presented. The net power output, thermal and exergy efficiencies and the products of the heat transfer coefficient (U) and the total heat exchange area (A) (UA values) were calculated for parametric optimization. Nine candidate working fluids were investigated and compared. Under the given conditions, transcritical systems have higher net power outputs than subcritical ones. The highest net power output of transcritical systems is 18.63 kW obtained by R218, and that of subcritical systems is 13.57 kW obtained by R600a. Moreover, with the increase of evaporating pressure, the thermal and exergy efficiencies of transcritical systems increase at first and then decrease, but the efficiencies of subcritical ones increase. As a result, the efficiencies of transcritical systems cannot always outperform those of the subcritical ones. However, the subcritical systems have lower minimum UA values and lower expansion ratios than the transcritical ones at the maximum net power output. In addition, the transcritical cycles have higher expansion ratios than the subcritical ones at their maximum net power output.

  16. The simulation of organic rankine cycle power plant with n-pentane working fluid

    Science.gov (United States)

    Nurhilal, Otong; Mulyana, Cukup; Suhendi, Nendi; Sapdiana, Didi

    2016-02-01

    In the steam power plant in Indonesia the dry steam from separator directly used to drive the turbin. Meanwhile, brine from the separator with low grade temperature reinjected to the earth. The brine with low grade temperature can be converted indirectly to electrical power by organic Rankine cycle (ORC) methods. In ORC power plant the steam are released from vaporization of organic working fluid by brine. The steam released are used to drive an turbine which in connected to generator to convert the mechanical energy into electric energy. The objective of this research is the simulation ORC power plant with n-pentane as organic working fluid. The result of the simulation for brine temperature around 165°C and the pressure 8.001 bar optained the net electric power around 1173 kW with the cycle thermal efficiency 14.61% and the flow rate of n-pentane around 15.51 kg/s. This result enable to applied in any geothermal source in Indonesia.

  17. Assessment Alternative Energy for Organic Rankine Cycle Power Plant in Thailand

    Directory of Open Access Journals (Sweden)

    Nattaporn Chaiyat

    2015-02-01

    Full Text Available This paper studies the possibility of power generation by using alternative energy in Thailand which are geothermal energy, solar energy and waste energy based on the energy and economy indicators. An Organic Rankine Cycle (ORC is used to generate electricity from heat sources of hot springs, solar water heating system and RDF-5, respectively. In this study, a 20 kW ORC system with using R-245fa as working fluid was tested and evaluated the system efficiency. It could be found that the efficiency of ORC system was around 8%, when hot water temperature was higher than 100 ºC. The values of levelized electricity costs (LEC of geothermal energy, solar energy and waste energy were 0.148, 0.547 and 0.442 USD/kWh, respectively. The suitable alternative energy for generating electricity was the geothermal energy which was beneficial than the solar and waste energy power plants in terms of energy and economy results.

  18. Real-Time Optimization of Organic Rankine Cycle Systems by Extremum-Seeking Control

    Directory of Open Access Journals (Sweden)

    Andres Hernandez

    2016-05-01

    Full Text Available In this paper, the optimal operation of a stationary sub-critical 11 kW el organic Rankine cycle (ORC unit for waste heat recovery (WHR applications is investigated, both in terms of energy production and safety conditions. Simulation results of a validated dynamic model of the ORC power unit are used to derive a correlation for the evaporating temperature, which maximizes the power generation for a range of operating conditions. This idea is further extended using a perturbation-based extremum seeking (ES algorithm to identify online the optimal evaporating temperature. Regarding safety conditions, we propose the use of the extended prediction self-adaptive control (EPSAC approach to constrained model predictive control (MPC. Since it uses input/output models for prediction, it avoids the need for state estimators, making it a suitable tool for industrial applications. The performance of the proposed control strategy is compared to PID-like schemes. Results show that EPSAC-MPC is a more effective control strategy, as it allows a safer and more efficient operation of the ORC unit, as it can handle constraints in a natural way, operating close to the boundary conditions where power generation is maximized.

  19. Experimental and Thermoeconomic Analysis of Small-Scale Solar Organic Rankine Cycle (SORC System

    Directory of Open Access Journals (Sweden)

    Suresh Baral

    2015-04-01

    Full Text Available A small-scale solar organic Rankine cycle (ORC is a promising renewable energy-driven power generation technology that can be used in the rural areas of developing countries. A prototype was developed and tested for its performance characteristics under a range of solar source temperatures. The solar ORC system power output was calculated based on the thermal and solar collector efficiency. The maximum solar power output was observed in April. The solar ORC unit power output ranged from 0.4 kW to 1.38 kW during the year. The highest power output was obtained when the expander inlet pressure was 13 bar and the solar source temperature was 120 °C. The area of the collector for the investigation was calculated based on the meteorological conditions of Busan City (South Korea. In the second part, economic and thermoeconomic analyses were carried out to determine the cost of energy per kWh from the solar ORC. The selling price of electricity generation was found to be $0.68/kWh and $0.39/kWh for the prototype and low cost solar ORC, respectively. The sensitivity analysis was carried out in order to find the influencing economic parameters for the change in NPV. Finally, the sustainability index was calculated to assess the sustainable development of the solar ORC system.

  20. Performance of Organic Rankine Cycle in Different Refrigerants for Low Temperature Geothermal using Delphi Program

    Directory of Open Access Journals (Sweden)

    Prabowo .

    2010-01-01

    Full Text Available A software has been developed in a Windows-based Delphi programming for analyzing the influence of the transport and thermodynamic properties of the refrigerants on the performance of the Organic Rankine Cycle (ORC. Its user-friendly drag and drop icon format and excellent color graphics make it an interactive tool for teaching and the preliminary design of the ORC system. The research was carried out by analyzing the performance of the system components and the overall ORC based on the several working fluids within R22, R123, R134a and RC318. The pressure of evaporator was varied in two steps 7 and 12 bar, while the condenser was kept constant pressure at 1 bar. The turbine inlet temperature was varied in the range 100 0C to 140 0C where the various isentropic efficiency inputs were applied for pump and turbine. By increasing turbine inlet temperature, R22 has the highest turbine work output and cycle efficiency. Contrary, RC318 has the lowest cycle efficiency and decreases trend with enhancing in turbine inlet temperature. RC318 has low latent heat of vaporization thus vaporizes under relatively very low evaporator heat supply.

  1. Selection of organic Rankine cycle working fluid based on unit-heat-exchange-area net power

    Institute of Scientific and Technical Information of China (English)

    郭美茹; 朱启的; 孙志强; 周天; 周孑民

    2015-01-01

    To improve energy conversion efficiency, optimization of the working fluids in organic Rankine cycles (ORCs) was explored in the range of low-temperature heat sources. The concept of unit-heat-exchange-area (UHEA) net power, embodying the cost/performance ratio of an ORC system, was proposed as a new indicator to judge the suitability of ORC working fluids on a given condition. The heat exchange area was computed by an improved evaporator model without fixing the minimum temperature difference between working fluid and hot fluid, and the flow pattern transition during heat exchange was also taken into account. The maximum UHEA net powers obtained show that dry organic fluids are more suitable for ORCs than wet organic fluids to recover low-temperature heat. The organic fluid 1-butene is recommended if the inlet temperature of hot fluid is 353.15−363.15 K or 443.15−453.15 K, heptane is more suitable at 373.15−423.15 K, and R245ca is a good option at 483.15−503.15 K.

  2. Performance analysis of an organic Rankine cycle with internal heat exchanger having zeotropic working fluid

    Directory of Open Access Journals (Sweden)

    Thoranis Deethayat

    2015-09-01

    Full Text Available In this study, performance of a 50 kW organic Rankine cycle (ORC with internal heat exchanger (IHE having R245fa/R152a zeotropic refrigerant with various compositions was investigated. The IHE could reduce heat rate at the ORC evaporator and better cycle efficiency could be obtained. The zeotropic mixture could reduce the irreversibilities during the heat exchanges at the ORC evaporator and the ORC condenser due to its gliding temperature; thus the cycle working temperatures came closer to the temperatures of the heat source and the heat sink. In this paper, effects of evaporating temperature, mass fraction of R152a and effectiveness of internal heat exchanger on the ORC performances for the first law and the second law of thermodynamics were considered. The simulated results showed that reduction of R245fa composition could reduce the irreversibilities at the evaporator and the condenser. The suitable composition of R245fa was around 80% mass fraction and below this the irreversibilities were nearly steady. Higher evaporating temperature and higher internal heat exchanger effectiveness also increased the first law and second law efficiencies. A set of correlations to estimate the first and the second law efficiencies with the mass fraction of R245fa, the internal heat exchanger effectiveness and the evaporating temperature were also developed.

  3. Thermo-Economic Evaluation of Organic Rankine Cycles for Geothermal Power Generation Using Zeotropic Mixtures

    Directory of Open Access Journals (Sweden)

    Florian Heberle

    2015-03-01

    Full Text Available We present a thermo-economic evaluation of binary power plants based on the Organic Rankine Cycle (ORC for geothermal power generation. The focus of this study is to analyse if an efficiency increase by using zeotropic mixtures as working fluid overcompensates additional requirements regarding the major power plant components. The optimization approach is compared to systems with pure media. Based on process simulations, heat exchange equipment is designed and cost estimations are performed. For heat source temperatures between 100 and 180 °C selected zeotropic mixtures lead to an increase in second law efficiency of up to 20.6% compared to pure fluids. Especially for temperatures about 160 °C, mixtures like propane/isobutane, isobutane/isopentane, or R227ea/R245fa show lower electricity generation costs compared to the most efficient pure fluid. In case of a geothermal fluid temperature of 120 °C, R227ea and propane/isobutane are cost-efficient working fluids. The uncertainties regarding fluid properties of zeotropic mixtures, mainly affect the heat exchange surface. However, the influence on the determined economic parameter is marginal. In general, zeotropic mixtures are a promising approach to improve the economics of geothermal ORC systems. Additionally, the use of mixtures increases the spectrum of potential working fluids, which is important in context of present and future legal requirements considering fluorinated refrigerants.

  4. Experimental Investigation of the Performance of a Hermetic Screw-Expander Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Sung-Wei Hsu

    2014-09-01

    Full Text Available In this study, the authors experimentally investigate the performance of the organic Rankine cycle (ORC and screw expander under the influence of supply pressure and pressure ratio over the expander. Three tests were performed with expander pressure ratios of 2.4–3.5, 3.0–4.6, and 3.3–6.1, which cover the over-expansion and under-expansion operating modes. The test results show a maximum expander isentropic efficiency of 72.4% and a relative cycle efficiency of 10.5% at an evaporation temperature of 101 °C and condensation temperature of 45 °C. At a given pressure ratio over the expander, a higher supply pressure to the expander causes a higher expander isentropic efficiency and higher cycle efficiency in the over-expansion mode. However, in the under-expansion mode, the higher supply pressure results in a lower expander isentropic efficiency and adversely affects the cycle efficiency. The results also show that under the condition of operation at a given pressure ratio, a higher supply pressure yields a larger power output owing to the increased mass flow rate at the higher supply pressure. The study results demonstrate that a screw-expander ORC can be operated with a wide range of heat sources and heat sinks with satisfactory cycle efficiency.

  5. A Flow Rate Control Approach on Off-Design Analysis of an Organic Rankine Cycle System

    Directory of Open Access Journals (Sweden)

    Ben-Ran Fu

    2016-09-01

    Full Text Available This study explored effects of off-design heat source temperature (TW,in or flow rate (mW on heat transfer characteristics and performance of an organic Rankine cycle system by controlling the flow rate of working fluid R245fa (i.e., the operation flow rate of R245fa was controlled to ensure that R245fa reached saturation liquid and vapor states at the outlets of the preheater and evaporator, respectively. The results showed that the operation flow rate of R245fa increased with TW,in or mW; higher TW,in or mW yielded better heat transfer performance of the designed preheater and required higher heat capacity of the evaporator; heat transfer characteristics of preheater and evaporator differed for off-design TW,in and mW; and net power output increased with TW,in or mW. The results further indicated that the control strategy should be different for various off-design conditions. Regarding maximum net power output, the flow rate control approach is optimal when TW,in or mW exceeds the design point, but the pressure control approach is better when TW,in or mW is lower than the design point.

  6. Simulation of a passive house coupled with a heat pump/organic Rankine cycle reversible unit

    DEFF Research Database (Denmark)

    Dumont, Olivier; Carmo, Carolina; Randaxhe, François

    2014-01-01

    modes that need to be chosen optimally depending on the weather conditions, the heat demand and the temperature level of the storage. The ORC mode is activated, as long as the heat demand of the house is covered by the storage to produce electricity based upon the heat generated by the solar roof...... regarding control strategies and enhancement of the global system are drawn. A control strategy with a low storage temperature set-point (50˚C) allows reducing electrical consumption from 11% up to 24% when compared to higher set-point (60˚C). The system performance to produce power could also be optimized......This paper presents a dynamic model of a passive house located in Denmark with a large solar absorber, a horizontal ground heat exchanger coupled with a HP/ORC unit. The HP/ORC reversible unit is a module able to work as an Organic Rankine Cycle (ORC) or as a heat pump (HP). There are 3 possible...

  7. Evaluation of a solar-powered organic Rankine cycle using dry organic working fluids

    Directory of Open Access Journals (Sweden)

    Emily Spayde

    2015-12-01

    Full Text Available This paper presents a model to evaluate the performance of a solar-powered organic Rankine cycle (ORC. The system was evaluated in Jackson, MS, using five dry organic working fluids, R218, R227ea, R236ea, R236fa, and RC318. The purpose of this study is to investigate how hourly temperature change affects the electricity production and exergy destruction rates of the solar ORC, and to determine the effect of the working fluid on the proposed system. The system was also evaluated in Tucson, AZ, to investigate the effect of average hourly outdoor temperatures on its performance. The potential of the system to reduce primary energy consumption and carbon dioxide emissions is also investigated. A parametric analysis to determine how temperature and pressure of the organic working fluid, the solar collector area, and the turbine efficiency affect the electricity production is performed. Results show that the ORC produces the most electricity during the middle of the day, when the temperatures are the highest and when the solar collectors have the highest efficiency. Also, R-236ea is the working fluid that shows the best performance of the evaluated fluids. An economic analysis was performed to determine the capital cost available for the proposed system.

  8. Organic Rankine Cycle Analysis: Finding the Best Way to Utilize Waste Heat

    Directory of Open Access Journals (Sweden)

    Nadim Chakroun

    2012-01-01

    Full Text Available An Organic Rankine Cycle (ORC is a type of power cyclethat uses organic substances such as hydrocarbons orrefrigerants as the working fluid. ORC technology is usedto generate electricity in waste heat recovery applications,because the available heat is not at a high enoughtemperature to operate with other types of cycles. Theoptimum amount of working fluid required for the cycle(i.e., optimum charge level was investigated. Three chargelevels (13, 15, and 18 lbm were tested, and their effect onefficiency and performance of the system was analyzed.The heat source for the fluid was waste steam from thePurdue Power Plant, which had an average temperatureof 120oC. Regular city tap water at a temperature of 15oCwas used as the heat sink. For each charge level, multipletests were performed by measuring the temperaturesand pressures at all state points in the cycle, in order tounderstand any overarching patterns within the data.An important parameter that was analyzed is the 2nd lawefficiency. This efficiency is a measure of the effectivenessof the energy utilization compared to that of an idealcase. The peak efficiency increased from 24% to 27% asthe charge in the system decreased. Therefore, movingforward, this research suggests that a lower charge levelin the system will increase efficiency. However, testingbelow 13 lbm might cause mechanical complications inthe equipment as there may not be enough fluid to flowaround; thus, a compromise had to be made.

  9. Optimization of Low-Temperature Exhaust Gas Waste Heat Fueled Organic Rankine Cycle

    Institute of Scientific and Technical Information of China (English)

    WANGHui—tao; WANGHua; ZHANGZhu—ming

    2012-01-01

    Low temperature exhaust gases carrying large amount of waste heat are released by steel-making process and many other industries, Organic Rankine Cycles (ORCs) are proven to be the most promising technology to re- cover the low-temperature waste heat, thereby to get more financial benefits for these industries. The exergy analysis of ORC units driven by low-temperature exhaust gas waste heat and charged with dry and isentropic fluid was per- formed, and an intuitive approach with simple impressions was developed to calculate the performances of the ORC unit. Parameter optimization was conducted with turbine inlet temperature simplified as the variable and exergy effi- ciency or power output as the objective function by means of Penalty Function and Golden Section Searching algo- rithm based on the formulation of the optimization problem. The power generated by the optimized ORC unit can be nearly as twice as that generated by a non-optimized ORC unit. In addition, cycle parametric analysis was performed to examine the effects of thermodynamic parameters on the cycle performances such as thermal efficiency and exergy efficiency. It is proven that performance of ORC unit is mainly affected by the thermodynamic property of working fluid, the waste heat temperature, the pinch point temperature of the evaporator, the specific heat capacity of the heat carrier and the turbine inlet temperature under a given environment temperature.

  10. Thermodynamic analysis of an integrated gasification solid oxide fuel cell plant combined with an organic Rankine cycle

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Rokni, Masoud; Larsen, Ulrik

    2013-01-01

    into a fixed bed gasification plant to produce syngas which fuels the combined solid oxide fuel cells e organic Rankine cycle system to produce electricity. More than a hundred fluids are considered as possible alternative for the organic cycle using non-ideal equations of state (or state-of-the-art equations......A 100 kWe hybrid plant consisting of gasification system, solid oxide fuel cells and organic Rankine cycle is presented. The nominal power is selected based on cultivation area requirement. For the considered output a land of around 0.5 km2 needs to be utilized. Woodchips are introduced...... of state). A genetic algorithm is employed to select the optimal working fluid and the maximum pressure for the bottoming cycle. Thermodynamic and physical properties, environmental impacts and hazard specifications are also considered in the screening process. The results suggest that efficiencies...

  11. Sustainable energy conversion through the use of Organic Rankine Cycles for waste heat recovery and solar applications

    OpenAIRE

    Quoilin, Sylvain

    2011-01-01

    This thesis contributes to the knowledge and the characterization of small-scale Organic Rankine Cycles (ORC). It is based on experimental data, thermodynamic models and case studies. The experimental studies include: 1. A prototype of small-scale waste heat recovery ORC using an open-drive oil-free scroll expander, declined in two successive versions with major improvements. 2. A prototype of hermetic scroll expander tested on vapor test rig designed for that purpose. The achieve...

  12. Stand-Alone Solar Organic Rankine Cycle Water Pumping System and Its Economic Viability in Nepal

    Directory of Open Access Journals (Sweden)

    Suresh Baral

    2015-12-01

    Full Text Available The current study presents the concept of a stand-alone solar organic Rankine cycle (ORC water pumping system for rural Nepalese areas. Experimental results for this technology are presented based on a prototype. The economic viability of the system was assessed based on solar radiation data of different Nepalese geographic locations. The mechanical power produced by the solar ORC is coupled with a water pumping system for various applications, such as drinking and irrigation. The thermal efficiency of the system was found to be 8% with an operating temperature of 120 °C. The hot water produced by the unit has a temperature of 40 °C. Economic assessment was done for 1-kW and 5-kW solar ORC water pumping systems. These systems use different types of solar collectors: a parabolic trough collector (PTC and an evacuated tube collector (ETC. The economic analysis showed that the costs of water are $2.47/m3 (highest and $1.86/m3 (lowest for the 1-kW system and a 150-m pumping head. In addition, the cost of water is reduced when the size of the system is increased and the pumping head is reduced. The minimum volumes of water pumped are 2190 m3 and 11,100 m3 yearly for 1 kW and 5 kW, respectively. The payback period is eight years with a profitability index of 1.6. The system is highly feasible and promising in the context of Nepal.

  13. DESIGN AND PARAMETRIC OPTIMIZATION OF AN ORGANIC RANKINE CYCLE POWERED BY SOLAR ENERGY

    Directory of Open Access Journals (Sweden)

    Francesco Calise

    2013-01-01

    Full Text Available This study presents the simulation and performance analysis of a regenerative and superheated Organic Rankine Cycle (ORC. To this scope, anew simulation model has been developed. The model is based on zero-dimensional energy and mass balances for all the components of the system. Shell and tube heat expanders with single shell and double tube pass have been chosen. Pump and expander have been considered only form a thermodynamic point of view, with constant compressor and expansion efficiency. The simulations have been carried out in order to find different optimization criteria to use as preliminary design tools, especially for the organic fluid choice and the heat exchanger design. Firstly, the ORC performances have been evaluated for different organic medium, varying the temperature of the heat source. The global efficiency of the plant, the net electric power generation and the volumetric expansion ratio has been considered as evaluation parameters. The simulation results show that two hydrocarbons demonstrate good performance for low, medium and high heat source, namely Isobutene, n-Butene; R245fa can add to them for the exploitation of heat source up to 170°C. Additional simulations have been carried out to discover an optimization criterion for the heat exchanger design. The plant performances have been first evaluated varying one by one the following parameters: tube length, tube number and shell diameter. Then a global optimization was also performed using the Golden Search technique. The total cost of the plant has been considered as objective functions. With respect to the objective function, higher the boiling heat transfer area higher the electric power generation and the economical benefit. The optimal configuration, compared to the initial one, shows an increase of incomes and mechanical power equal to 60.1 and 48.2% respectively, against a decrease of global efficiency equal to 10.9%.

  14. Analysis and optimization of the low-temperature solar organic Rankine cycle (ORC)

    Energy Technology Data Exchange (ETDEWEB)

    Delgado-Torres, Agustin M. [Dpto. Fisica Fundamental y Experimental, Electronica y Sistemas, Escuela Tecnica Superior de Ingenieria Civil e Industrial, Universidad de La Laguna (ULL), Avda, Astrofisico Francisco Sanchez s/n, 38206 La Laguna, Tenerife (Spain); Garcia-Rodriguez, Lourdes [Dpto. Ingenieria Energetica, Escuela Tecnica Superior de Ingenieros, Universidad de Sevilla, Camino de los Descubrimientos, s/n 41092 Sevilla (Spain)

    2010-12-15

    Solar thermal driven reverse osmosis desalination is a promising renewable energy-driven desalination technology. A joint use of the solar thermal powered organic Rankine cycle (ORC) and the desalination technology of less energy consumption, reverse osmosis (RO), makes this combination interesting in some scarce water resource scenarios. However, prior to any practical experience with any new process, a comprehensive and rigorous theoretical study must be done in order to assess the performance of the new technology or combination of existing technologies. The main objective of the present paper is the expansion of the theoretical analysis done by the authors in previous works to the case in which the thermal energy required by a solar ORC is supplied by means of stationary solar collectors. Twelve substances are considered as working fluids of the ORC and four different models of stationary solar collectors (flat plate collectors, compound parabolic collectors and evacuated tube collectors) are also taken into account. Operating conditions of the solar ORC that minimizes the aperture area needed per unit of mechanical power output of the solar cycle are determined for every working fluid and every solar collector. The former is done considering a direct vapour generation configuration of the solar cycle and also the configuration with water as heat transfer fluid flowing inside the solar collector. This work is part of the theoretical analysis of the solar thermal driven seawater and brackish water reverse osmosis desalination technology. Nevertheless, the supplied information can be also used for the assessment of different applications of the solar ORC. In that case, results presented in this paper can be useful in techno-economic analysis, selection of working fluids of the Rankine cycle, sizing of systems and assessment of solar power cycle configuration. (author)

  15. Development and a Validation of a Charge Sensitive Organic Rankine Cycle (ORC Simulation Tool

    Directory of Open Access Journals (Sweden)

    Davide Ziviani

    2016-05-01

    Full Text Available Despite the increasing interest in organic Rankine cycle (ORC systems and the large number of cycle models proposed in the literature, charge-based ORC models are still almost absent. In this paper, a detailed overall ORC simulation model is presented based on two solution strategies: condenser subcooling and total working fluid charge of the system. The latter allows the subcooling level to be predicted rather than specified as an input. The overall cycle model is composed of independent models for pump, expander, line sets, liquid receiver and heat exchangers. Empirical and semi-empirical models are adopted for the pump and expander, respectively. A generalized steady-state moving boundary method is used to model the heat exchangers. The line sets and liquid receiver are used to better estimate the total charge of the system and pressure drops. Finally, the individual components are connected to form a cycle model in an object-oriented fashion. The solution algorithm includes a preconditioner to guess reasonable values for the evaporating and condensing temperatures and a main cycle solver loop which drives to zero a set of residuals to ensure the convergence of the solution. The model has been developed in the Python programming language. A thorough validation is then carried out against experimental data obtained from two test setups having different nominal size, working fluids and individual components: (i a regenerative ORC with a 5 kW scroll expander and an oil flooding loop; (ii a regenerative ORC with a 11 kW single-screw expander. The computer code is made available through open-source dissemination.

  16. The role of outlet temperature of flue gas in organic Rankine cycle considering low temperature corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Shuang Ying; Li, Chun; Xiao, Lan; Li, You Rong; Liu, Chao [Chongqing University, Chongqing (China)

    2014-12-15

    This paper gives a special focus on the role of outlet temperature of flue gas (T{sub go}) in organic Rankine cycle (ORC) system for low temperature flue gas waste heat recovery. The variations of performance indicators: net work (W{sub net}), exergy efficiency (η{sub ex}) and levelized energy cost (LEC) versus T{sub go} are discussed. Considering the corrosion of low temperature flue gas, the necessity and reasonability of limiting T{sub go} at its minimum allowed discharge temperature (355.15 K) are analyzed. Results show that there exist optimal T{sub go} (T{sub go,opt}) for W{sub net} and LEC, while T{sub go,opt} for η{sub ex} does not appear under the investigated range of T{sub go}. Moreover, the T{sub go,opt} for W{sub net} is always lower than 355.15 K, the T{sub go,opt} for LEC, despite being greater than the one for W{sub net}, is just slightly higher than 355.15 K when the inlet temperature of flue gas varies from 408.15 K to 463.15 K. For the waste heat recovery of low temperature flue gas, it is reasonable to fix T{sub go} at 355.15K if W{sub net} or LEC is selected as primary performance indicator under the pinch point temperature difference of evaporator (ΔT{sub e}) below 20K.

  17. Dual-objective optimization of organic Rankine cycle (ORC) systems using genetic algorithm: a comparison between basic and recuperative cycles

    Science.gov (United States)

    Hayat, Nasir; Ameen, Muhammad Tahir; Tariq, Muhammad Kashif; Shah, Syed Nadeem Abbas; Naveed, Ahmad

    2017-03-01

    Exploitation of low potential waste thermal energy for useful net power output can be done by manipulating organic Rankine cycle systems. In the current article dual-objectives ({{η}}_{th} and SIC) optimization of ORC systems [basic organic Rankine cycle (BORC) and recuperative organic Rankine cycle (RORC)] has been done using non-dominated sorting genetic algorithm (II). Seven organic compounds (R-123, R-1234ze, R-152a, R-21, R-236ea, R-245ca and R-601) have been employed in basic cycle and four dry compounds (R-123, R-236ea, R-245ca and R-601) have been employed in recuperative cycle to investigate the behaviour of two systems and compare their performance. Sensitivity analyses show that recuperation boosts the thermodynamic behaviour of systems but it also raises specific investment cost significantly. R-21, R-245ca and R-601 show attractive performance in BORC whereas R-601 and R-236ea in RORC. RORC, due to higher total investment cost and operation & maintenance costs, has longer payback periods as compared to BORC.

  18. Performance Analysis of a Shell Tube Condenser for a Model Organic Rankine Cycle for Use in Geothermal Power Plant

    Directory of Open Access Journals (Sweden)

    Haile Araya Nigusse

    2014-08-01

    Full Text Available The global energy demand increases with the economic growth and population rise. Most electrical power is currently generated by conventional methods from fossil fuels. Despite the high energy demand, the conventional energy resources such as fossil fuels have been declining. In addition to this harmful combustion byproducts are resulting global warming. However, the increase of environmental concerns and energy crisis can be minimized by sustainable utilization of the low to medium temperature heat resources. The Organic Rankine Cycle power plant is a very effective option for utilization of low grade heat sources for power generation. Heat exchangers are the main components of the Organic Rankine Cycle power plant which receives heat energy from the heat source to evaporate and condense the low boiling temperature organic working fluid which in turn drives the turbine to generate power. This paper presents a simplified approach to the design, fabrication and performance assessment of a shell tube heat exchanger designed for condenser in a model Organic Rankine Cycle geothermal power plant. The design involved sizing of heat exchanger (condenser using the LMTD method based on an expected heat transfer rate. The heat exchanger of the model power plant was tested in which hot water simulated geothermal brine. The results of the experiment indicated that the heat exchanger is thermally suitable for the condenser of the model power plant.

  19. Dual-objective optimization of organic Rankine cycle (ORC) systems using genetic algorithm: a comparison between basic and recuperative cycles

    Science.gov (United States)

    Hayat, Nasir; Ameen, Muhammad Tahir; Tariq, Muhammad Kashif; Shah, Syed Nadeem Abbas; Naveed, Ahmad

    2017-08-01

    Exploitation of low potential waste thermal energy for useful net power output can be done by manipulating organic Rankine cycle systems. In the current article dual-objectives (η_{th} and SIC) optimization of ORC systems [basic organic Rankine cycle (BORC) and recuperative organic Rankine cycle (RORC)] has been done using non-dominated sorting genetic algorithm (II). Seven organic compounds (R-123, R-1234ze, R-152a, R-21, R-236ea, R-245ca and R-601) have been employed in basic cycle and four dry compounds (R-123, R-236ea, R-245ca and R-601) have been employed in recuperative cycle to investigate the behaviour of two systems and compare their performance. Sensitivity analyses show that recuperation boosts the thermodynamic behaviour of systems but it also raises specific investment cost significantly. R-21, R-245ca and R-601 show attractive performance in BORC whereas R-601 and R-236ea in RORC. RORC, due to higher total investment cost and operation & maintenance costs, has longer payback periods as compared to BORC.

  20. A Comparative Exergoeconomic Analysis of Waste Heat Recovery from a Gas Turbine-Modular Helium Reactor via Organic Rankine Cycles

    Directory of Open Access Journals (Sweden)

    Naser Shokati

    2014-04-01

    Full Text Available A comparative exergoeconomic analysis is reported for waste heat recovery from a gas turbine-modular helium reactor (GT-MHR using various configurations of organic Rankine cycles (ORCs for generating electricity. The ORC configurations studied are: a simple organic Rankine cycle (SORC, an ORC with an internal heat exchanger (HORC and a regenerative organic Rankine cycle (RORC. Exergoeconomic analyses are performed with the specific exergy costing (SPECO method. First, energy and exergy analyses are applied to the combined cycles. Then, a cost-balance, as well as auxiliary equations are developed for the components to determine the exergoeconomic parameters for the combined cycles and their components. The three combined cycles are compared considering the same operating conditions for the GT-MHR cycle, and a parametric study is done to reveal the effects on the exergoeconomic performance of the combined cycles of various significant parameters, e.g., turbine inlet and evaporator temperatures and compressor pressure ratio. The results show that the GT-MHR/RORC has the lowest unit cost of electricity generated by the ORC turbine. This value is highest for the GT-MHR/HORC. Furthermore, the GT-MHR/RORC has the highest and the GT-MHR/HORC has the lowest exergy destruction cost rate.

  1. An experimental analysis of flow boiling and pressure drop in a brazed plate heat exchanger for organic Rankine cycle power systems

    DEFF Research Database (Denmark)

    Desideri, Adriano; Zhang, Ji; Kærn, Martin Ryhl

    2017-01-01

    Organic Rankine cycle power systems for low quality waste heat recovery applications can play a major role in achieving targets of increasing industrial processes efficiency and thus reducing the emissions of greenhouse gases. Low capacity organic Rankine cycle systems are equipped with brazed...... and pressure drop during vaporization at typical temperatures for low quality waste heat recovery organic Rankine cycle systems are presented for the working fluids HFC-245fa and HFO-1233zd. The experiments were carried out at saturation temperatures of 100°C, 115°C and 130°C and inlet and outlet qualities...

  2. Design and optimization of organic rankine cycle for low temperature geothermal power plant

    Science.gov (United States)

    Barse, Kirtipal A.

    Rising oil prices and environmental concerns have increased attention to renewable energy. Geothermal energy is a very attractive source of renewable energy. Although low temperature resources (90°C to 150°C) are the most common and most abundant source of geothermal energy, they were not considered economical and technologically feasible for commercial power generation. Organic Rankine Cycle (ORC) technology makes it feasible to use low temperature resources to generate power by using low boiling temperature organic liquids. The first hypothesis for this research is that using ORC is technologically and economically feasible to generate electricity from low temperature geothermal resources. The second hypothesis for this research is redesigning the ORC system for the given resource condition will improve efficiency along with improving economics. ORC model was developed using process simulator and validated with the data obtained from Chena Hot Springs, Alaska. A correlation was observed between the critical temperature of the working fluid and the efficiency for the cycle. Exergy analysis of the cycle revealed that the highest exergy destruction occurs in evaporator followed by condenser, turbine and working fluid pump for the base case scenarios. Performance of ORC was studied using twelve working fluids in base, Internal Heat Exchanger and turbine bleeding constrained and non-constrained configurations. R601a, R245ca, R600 showed highest first and second law efficiency in the non-constrained IHX configuration. The highest net power was observed for R245ca, R601a and R601 working fluids in the non-constrained base configuration. Combined heat exchanger area and size parameter of the turbine showed an increasing trend as the critical temperature of the working fluid decreased. The lowest levelized cost of electricity was observed for R245ca followed by R601a, R236ea in non-constrained base configuration. The next best candidates in terms of LCOE were R601a, R

  3. Preliminary Design and Simulation of a Turbo Expander for Small Rated Power Organic Rankine Cycle (ORC

    Directory of Open Access Journals (Sweden)

    Roberto Capata

    2014-11-01

    Full Text Available Nowadays, the Organic Rankine Cycle (ORC system, which operates with organic fluids, is one of the leading technologies for “waste energy recovery”. It works as a conventional Rankine Cycle but, as mentioned, instead of steam/water, an organic fluid is used. This change allows it to convert low temperature heat into electric energy where required. Large numbers of studies have been carried out to identify the most suitable fluids, system parameters and the various configurations. In the present market, most ORC systems are designed and manufactured for the recovery of thermal energy from various sources operating at “large power rating” (exhaust gas turbines, internal combustion engines, geothermal sources, large melting furnaces, biomass, solar, etc.; from which it is possible to produce a large amount of electric energy (30 kW ÷ 300 kW. Such applications for small nominal power sources, as well as the exhaust gases of internal combustion engines (car sedan or town, ships, etc. or small heat exchangers, are very limited. The few systems that have been designed and built for small scale applications, have, on the other hand, different types of expander (screw, scroll, etc.. These devices are not adapted for placement in small and restricted places like the interior of a conventional car. The aim of this work is to perform the preliminary design of a turbo-expander that meets diverse system requirements such as low pressure, small size and low mass flow rates. The expander must be adaptable to a small ORC system utilizing gas of a diesel engine or small gas turbine as thermal source to produce 2–10 kW of electricity. The temperature and pressure of the exhaust gases, in this case study (400–600 °C and a pressure of 2 bar, imposes a limit on the use of an organic fluid and on the net power that can be produced. In addition to water, fluids such as CO2, R134a and R245fa have been considered. Once the operating fluids has been chosen

  4. Technology for industrial waste heat recovery by organic Rankine cycle systems

    Science.gov (United States)

    Cain, W. G.; Drake, R. L.; Prisco, C. J.

    1984-10-01

    The recovery of industrial waste heat and the conversion thereof to useful electric power by use of Rankine cycle systems is studied. Four different aspects of ORC technology were studied: possible destructive chemical reaction between an aluminum turbine wheel and R-113 working fluid under wheel-to-rotor rub conditions; possible chemical reaction between stainless steel or carbon steel and any of five different ORC working fluids under rotor-stator rub conditions; effects on electric generator properties of extended exposure to an environment of saturated R-113 vapor/fluid; and operational proof tests under laboratory conditions of two 1070 kW, ORC, R-113 hermetic turbogenerator power module systems.

  5. Analysis of the Properties of Working Substances for the Organic Rankine Cycle based Database “REFPROP”

    Directory of Open Access Journals (Sweden)

    Galashov Nikolay

    2016-01-01

    Full Text Available The object of the study are substances that are used as a working fluid in systems operating on the basis of an organic Rankine cycle. The purpose of research is to find substances with the best thermodynamic, thermal and environmental properties. Research conducted on the basis of the analysis of thermodynamic and thermal properties of substances from the base “REFPROP” and with the help of numerical simulation of combined-cycle plant utilization triple cycle, where the lower cycle is an organic Rankine cycle. Base “REFPROP” describes and allows to calculate the thermodynamic and thermophysical parameters of most of the main substances used in production processes. On the basis of scientific publications on the use of working fluids in an organic Rankine cycle analysis were selected ozone-friendly low-boiling substances: ammonia, butane, pentane and Freon: R134a, R152a, R236fa and R245fa. For these substances have been identified and tabulated molecular weight, temperature of the triple point, boiling point, at atmospheric pressure, the parameters of the critical point, the value of the derivative of the temperature on the entropy of the saturated vapor line and the potential ozone depletion and global warming. It was also identified and tabulated thermodynamic and thermophysical parameters of the steam and liquid substances in a state of saturation at a temperature of 15 °C. This temperature is adopted as the minimum temperature of heat removal in the Rankine cycle when working on the water. Studies have shown that the best thermodynamic, thermal and environmental properties of the considered substances are pentane, butane and R245fa. For a more thorough analysis based on a gas turbine plant NK-36ST it has developed a mathematical model of combined cycle gas turbine (CCGT triple cycle, where the lower cycle is an organic Rankine cycle, and is used as the air cooler condenser. Air condenser allows stating material at a temperature

  6. Parametric Optimization of Organic Rankine Cycle with R245fa/R601a as Working Fluid

    Institute of Scientific and Technical Information of China (English)

    Zhu Jialing; Kang Zhenhua; An Qingsong; Li Tailu

    2015-01-01

    In order to select the appropriate working fluids and optimize parameters for medium-temperature geothermally-powered organic Rankine cycle(ORC), R245fa is mixed with R601a atgeothermal water temperature of 110℃. Based on thermodynamics, the characteristics of mixture and its influence on the performance of ORC under different evaporating temperatures and composition proportionsare analyzed. Results show that the zeotropic mixture R245fa/R601a(0.4/0.6) has the highest performance. When the evaporating temperature reaches 67℃, the outlet temperature of geothermal water is 61℃, the net power output is the highest and the thermal efficiency is about 9%.

  7. Energy performance and economic evaluation of heat pump/organic rankine cycle system with sensible thermal storage

    DEFF Research Database (Denmark)

    Carmo, Carolina; Dumont, Olivier; Nielsen, Mads Pagh

    2016-01-01

    -life conditions knowledge, the paper considers two different sensible energy storage (TES) configurations for the reversible heat pump/organic Rankine cycle (HP/ORC) system: a buffer tank for both space heating and domestic hot water and a hot water storage tank used exclusively for domestic hot water...... that consists of a ground-source heat pump with possibility of reversing operation as an ORC power cycle combined with solar heating in a single-family building is introduced. The ORC mode enables the use of solar energy in periods of no heat energy demand and reverses the heat pump cycle to supply electrical...

  8. Effect of Regenerative Organic Rankine Cycle (RORC on the Performance of Solar Thermal Power in Yogyakarta, Indonesia

    Directory of Open Access Journals (Sweden)

    Ghalya Pikra

    2013-07-01

    Full Text Available This paper presents effect of Regenerative Organic Rankine Cycle (RORC on the performance of solar thermal power in Yogyakarta, Indonesia. Solar thermal power is a plant that uses solar energy as heat source. Indonesia has high humidity level, so that parabolic trough is the most suitable type of solar thermal power technology to be developed, where the design is made with small focal distance. Organic Rankine Cycle (ORC is a Rankine cycle that use organic fluid as working fluid to utilize low temperature heat sources. RORC is used to increase ORC performance. The analysis was done by comparing ORC system with and without regenerator addition. Refrigerant that be used in the analysis is R123. Preliminary data was taken from the solar collector system that has been installed in Yogyakarta. The analysis shows that with 36 m total parabolic length, the resulting solar collector capacity is 63 kW, heat input/evaporator capacity is determined 26.78 kW and turbine power is 3.11 kW for ORC, and 3.38 kW for RORC. ORC thermal efficiency is 11.28% and RORC is 12.26%. Overall electricity efficiency is 4.93% for ORC, and 5.36% for RORC. With 40°C condensing temperature and evaporation at 10 bar saturated condition, efficiency of RORC is higher than ORC. Greater evaporation temperature at the same pressure (10 bar provide greater turbine power and efficiency.

  9. Expansion of organic Rankine cycle working fluid in a cylinder of a low-speed two-stroke ship engine

    DEFF Research Database (Denmark)

    Larsen, Ulrik; Wronski, Jorrit; Andreasen, Jesper Graa

    2017-01-01

    Electricity and power produced from waste heat is particularly relevant in shipping because fuel expenses constitute the majority of the cost of operating the ships; however, the cost-benefit aspect limits the widespread implementation of waste heat recovery power units on ships. This paper...... for this concept. The evaluation of 104 working fluids points to cyclopropane, R245fa and R1234ze(z) as the most promising. The results suggest that the power produced by the organic Rankine cycle cylinder is at least equivalent to that of the cylinders operating with the diesel process. This enables potential...... fuel savings and emissions reductions of about 8.3% in the studied scenario....

  10. Thermal-Economic Modularization of Small, Organic Rankine Cycle Power Plants for Mid-Enthalpy Geothermal Fields

    Directory of Open Access Journals (Sweden)

    Yodha Y. Nusiaputra

    2014-07-01

    Full Text Available The costs of the surface infrastructure in mid-enthalpy geothermal power systems, especially in remote areas, could be reduced by using small, modular Organic Rankine Cycle (ORC power plants. Thermal-economic criteria have been devised to standardize ORC plant dimensions for such applications. We designed a modular ORC to utilize various wellhead temperatures (120–170 °C, mass flow rates and ambient temperatures (−10–40 °C. A control strategy was developed using steady-state optimization, in order to maximize net power production at off-design conditions. Optimum component sizes were determined using specific investment cost (SIC minimization and mean cashflow (MCF maximization for three different climate scenarios. Minimizing SIC did not yield significant benefits, but MCF proved to be a much better optimization function.

  11. An analytical study on the performance of the organic Rankine cycle for turbofan engine exhaust heat recovery

    Science.gov (United States)

    Saadon, S.; Abu Talib, A. R.

    2016-10-01

    Due to energy shortage and global warming, issues of energy saving have become more important. To increase the energy efficiency and reduce the fuel consumption, waste heat recovery is a significant method for energy saving. The organic Rankine cycle (ORC) has great potential to recover the waste heat from the core jet exhaust of a turbofan engine and use it to produce power. Preliminary study of the design concept and thermodynamic performance of this ORC system would assist researchers to predict the benefits of using the ORC system to extract the exhaust heat engine. In addition, a mathematical model of the heat transfer of this ORC system is studied and developed. The results show that with the increment of exhaust heat temperature, the mass flow rate of the working fluid, net power output and the system thermal efficiency will also increase. Consequently, total consumption of jet fuel could be significantly saved as well.

  12. Organic Rankine Cycle for Residual Heat to Power Conversion in Natural Gas Compressor Station. Part I: Modelling and Optimisation Framework

    Science.gov (United States)

    Chaczykowski, Maciej

    2016-06-01

    Basic organic Rankine cycle (ORC), and two variants of regenerative ORC have been considered for the recovery of exhaust heat from natural gas compressor station. The modelling framework for ORC systems has been presented and the optimisation of the systems was carried out with turbine power output as the variable to be maximized. The determination of ORC system design parameters was accomplished by means of the genetic algorithm. The study was aimed at estimating the thermodynamic potential of different ORC configurations with several working fluids employed. The first part of this paper describes the ORC equipment models which are employed to build a NLP formulation to tackle design problems representative for waste energy recovery on gas turbines driving natural gas pipeline compressors.

  13. Structural optimisation of a high speed Organic Rankine Cycle generator using a genetic algorithm and a finite element method

    Energy Technology Data Exchange (ETDEWEB)

    Palko, S. [Machines Division, ABB industry Oy, Helsinki (Finland)

    1997-12-31

    The aim in this work is to design a 250 kW high speed asynchronous generator using a genetic algorithm and a finite element method for Organic Rankine Cycle. The characteristics of the induction motors are evaluated using two-dimensional finite element method (FEM) The movement of the rotor and the non-linearity of the iron is included. In numerical field problems it is possible to find several local extreme for an optimisation problem, and therefore the algorithm has to be capable of determining relevant changes, and to avoid trapping to a local minimum. In this work the electromagnetic (EM) losses at the rated point are minimised. The optimisation includes the air gap region. Parallel computing is applied to speed up optimisation. (orig.) 2 refs.

  14. Study on the Characteristics of Expander Power Output Used for Offsetting Pumping Work Consumption in Organic Rankine Cycles

    Directory of Open Access Journals (Sweden)

    Yu-Ting Wu

    2014-07-01

    Full Text Available The circulation pump in an organic Rankine cycle (ORC increases the pressure of the liquid working fluid from low condensing pressure to high evaporating pressure, and the expander utilizes the pressure difference to generate work. A portion of the expander output power is used to offset the consumed pumping work, and the rest of the expander power is exactly the net work produced by the ORC system. Because of the relatively great theoretical pumping work and very low efficiency of the circulation pump reported in previous papers, the characteristics of the expander power used for offsetting the pumping work need serious consideration. In particular, the present work examines those characteristics. It is found that the characteristics of the expander power used for offsetting the pumping work are satisfactory only under the condition that the working fluid absorbs sufficient heat in the evaporator and its specific volume at the evaporator outlet is larger than or equal to a threshold value.

  15. Optimization of Cycle and Expander Design of an Organic Rankine Cycle Unit using Multi-Component Working Fluids

    DEFF Research Database (Denmark)

    Meroni, Andrea; Andreasen, Jesper Graa; Pierobon, Leonardo

    2016-01-01

    the irreversibility in the ORC system. This work considers mixtures of R245fa/pentane and propane/isobutane. The use of multi-component working fluids typically results in increased heat transfer areas and different expander designs compared to purefluids. In order to properly account for turbine performance...... for an organic Rankine cycle unit utilizing waste heat from low temperature heat sources. The study addresses a case where the minimum temperature of the heat source is constrained and a case where no constraint is imposed. The former case is the wasteheat recovery from jacket cooling water of a marine diesel...... engine onboard a large ship, and the latter is representative of a low-temperature geothermal, solar or waste heat recovery application. Multi-component working fluids are investigated, as they allow improving the match between the temperature pro-files in the heat exchangers and, consequently, reducing...

  16. Integrated working fluid-thermodynamic cycle design of organic Rankine cycle power systems for waste heat recovery

    DEFF Research Database (Denmark)

    Cignitti, Stefano; Andreasen, Jesper Graa; Haglind, Fredrik

    2017-01-01

    recovery. Inthis paper, an organic Rankine cycle process and its pure working fluid are designed simultaneously forwaste heat recovery of the exhaust gas from a marine diesel engine. This approach can overcome designissues caused by the high sensitivity between the fluid and cycle design variables...... and otherwise highresource demands, which through conventional methods cannot be addressed. The global optimal designwas a 1.2MW cycle with 2,2,3,3,4,4,5,5-octafluorohexane as the new fluid. The fluid has no ozone depletionpotential and a global warming potential under the regulatory limit. By using...... the simultaneousdesign approach the optimum solution was found in 5.04 s, while a decomposed approach found thesame solution in 5.77 h. However, the decomposed approach provided insights on the correlationbetween the fluid and cycle design variables by analyzing all possible solutions. It was shown that thehigh...

  17. Working fluid selection for the Organic Rankine Cycle (ORC) exhaust heat recovery of an internal combustion engine power plant

    Science.gov (United States)

    Douvartzides, S.; Karmalis, I.

    2016-11-01

    Organic Rankine cycle technology is capable to efficiently convert low-grade heat into useful mechanical power. In the present investigation such a cycle is used for the recovery of heat from the exhaust gases of a four stroke V18 MAN 51/60DF internal combustion engine power plant operating with natural gas. Design is focused on the selection of the appropriate working fluid of the Rankine cycle in terms of thermodynamic, environmental and safety criteria. 37 candidate fluids have been considered and all Rankine cycles examined were subcritical. The thermodynamic analysis of all fluids has been comparatively undertaken and the effect of key operation conditions such as the evaporation pressure and the superheating temperature was taken into account. By appropriately selecting the working fluid and the Rankine cycle operation conditions the overall plant efficiency was improved by 5.52% and fuel consumption was reduced by 12.69%.

  18. Application of Biomass from Palm Oil Mill for Organic Rankine Cycle to Generate Power in North Sumatera Indonesia

    Science.gov (United States)

    Nur, T. B.; Pane, Z.; Amin, M. N.

    2017-03-01

    Due to increasing oil and gas demand with the depletion of fossil resources in the current situation make efficient energy systems and alternative energy conversion processes are urgently needed. With the great potential of resources in Indonesia, make biomass has been considered as one of major potential fuel and renewable resource for the near future. In this paper, the potential of palm oil mill waste as a bioenergy source has been investigated. An organic Rankine cycle (ORC) small scale power plant has been preliminary designed to generate electricity. The working fluid candidates for the ORC plant based on the heat source temperature domains have been investigated. The ORC system with a regenerator has higher thermal efficiency than the basic ORC system. The study demonstrates the technical feasibility of ORC solutions in terms of resources optimizations and reducing of greenhouse gas emissions.

  19. 10-75-kWe-reactor-powered organic Rankine-cycle electric power systems (ORCEPS) study. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    1977-03-30

    This 10-75 kW(e) Reactor-ORCEPS study was concerned with the evaluation of several organic Rankine cycle energy conversion systems which utilized a /sup 235/U-ZrH reactor as a heat source. A liquid metal (NaK) loop employing a thermoelectric converter-powered EM pump was used to transfer the reactor energy to the organic working fluid. At moderate peak cycle temperatures (750/sup 0/F), power conversion unit cycle efficiencies of up to 25% and overall efficiencies of 20% can be obtained. The required operating life of seven years should be readily achievable. The CP-25 (toluene) working fluid cycle was found to provide the highest performance levels at the lowest system weights. Specific weights varies from 100 to 50 lb/kW(e) over the power level range 10 to 75 kW(e). (DLC)

  20. Thermodynamic and design considerations of organic Rankine cycles in combined application with a solar thermal gas turbine

    Science.gov (United States)

    Braun, R.; Kusterer, K.; Sugimoto, T.; Tanimura, K.; Bohn, D.

    2013-12-01

    Concentrated Solar Power (CSP) technologies are considered to provide a significant contribution for the electric power production in the future. Different kinds of technologies are presently in operation or under development, e.g. parabolic troughs, central receivers, solar dish systems and Fresnel reflectors. This paper takes the focus on central receiver technologies, where the solar radiation is concentrated by a field of heliostats in a receiver on the top of a tall tower. To get this CSP technology ready for the future, the system costs have to reduce significantly. The main cost driver in such kind of CSP technologies are the huge amount of heliostats. To reduce the amount of heliostats, and so the investment costs, the efficiency of the energy conversion cycle becomes an important issue. An increase in the cycle efficiency results in a decrease of the solar heliostat field and thus, in a significant cost reduction. The paper presents the results of a thermodynamic model of an Organic Rankine Cycle (ORC) for combined cycle application together with a solar thermal gas turbine. The gas turbine cycle is modeled with an additional intercooler and recuperator and is based on a typical industrial gas turbine in the 2 MW class. The gas turbine has a two stage radial compressor and a three stage axial turbine. The compressed air is preheated within a solar receiver to 950°C before entering the combustor. A hybrid operation of the gas turbine is considered. In order to achieve a further increase of the overall efficiency, the combined operation of the gas turbine and an Organic Rankine Cycle is considered. Therefore an ORC has been set up, which is thermally connected to the gas turbine cycle at two positions. The ORC can be coupled to the solar-thermal gas turbine cycle at the intercooler and after the recuperator. Thus, waste heat from different cycle positions can be transferred to the ORC for additional production of electricity. Within this investigation

  1. Performance analysis of exhaust heat recovery using organic Rankine cycle in a passenger car with a compression ignition engine

    Science.gov (United States)

    Ghilvacs, M.; Prisecaru, T.; Pop, H.; Apostol, V.; Prisecaru, M.; Pop, E.; Popescu, Gh; Ciobanu, C.; Mohanad, A.; Alexandru, A.

    2016-08-01

    Compression ignition engines transform approximately 40% of the fuel energy into power available at the crankshaft, while the rest part of the fuel energy is lost as coolant, exhaust gases and other waste heat. An organic Rankine cycle (ORC) can be used to recover this waste heat. In this paper, the characteristics of a system combining a compression ignition engine with an ORC which recover the waste heat from the exhaust gases are analyzed. The performance map of the diesel engine is measured on an engine test bench and the heat quantities wasted by the exhaust gases are calculated over the engine's entire operating region. Based on this data, the working parameters of ORC are defined, and the performance of a combined engine-ORC system is evaluated across this entire region. The results show that the net power of ORC is 6.304kW at rated power point and a maximum of 10% reduction in brake specific fuel consumption can be achieved.

  2. The Influence of the Heat Source Temperature on the Multivane Expander Output Power in an Organic Rankine Cycle (ORC System

    Directory of Open Access Journals (Sweden)

    Piotr Kolasiński

    2015-04-01

    Full Text Available Organic Rankine Cycle (ORC power systems are nowadays an option for local and domestic cogeneration of heat and electric power. Very interesting are micropower systems for heat recovery from low potential (40–90 °C waste and renewable heat sources. Designing an ORC system dedicated to heat recovery from such a source is very difficult. Most important problems are connected with the selection of a suitable expander. Volumetric machines, such as scroll and screw expanders, are adopted as turbine alternative in small-power ORC systems. However, these machines are complicated and expensive. Vane expanders on the other hand are simple and cheap. This paper presents a theoretical and experimental analysis of the operation of a micro-ORC rotary vane expander under variable heat source temperature conditions. The main objective of this research was therefore a comprehensive analysis of relation between the vane expander output power and the heat source temperature. A series of experiments was performed using the micropower ORC test-stand. Results of these experiments are presented here, together with a mathematical description of multivane expanders. The analysis presented in this paper indicates that the output power of multivane expanders depend on the heat source temperature, and that multivane expanders are cheap alternatives to other expanders proposed for micropower ORC systems.

  3. Performance Analysis and Working Fluid Selection of a Supercritical Organic Rankine Cycle for Low Grade Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    Yourong Li

    2012-08-01

    Full Text Available The performance analysis of a supercritical organic Rankine cycle system driven by exhaust heat using 18 organic working fluids is presented. Several parameters, such as the net power output, exergy efficiency, expander size parameter (SP, and heat exchanger requirement of evaporator and the condenser, were used to evaluate the performance of this recovery cycle and screen the working fluids. The results reveal that in most cases, raising the expander inlet temperature is helpful to improve the net power output and the exergy efficiency. However, the effect of the expander inlet pressure on those parameters is related to the expander inlet temperature and working fluid used. Either lower expander inlet temperature and pressure, or higher expander inlet temperature and pressure, generally makes the net power output more. Lower expander inlet temperature results in larger total heat transfer requirement and expander size. According to the screening criteria of both the higher output and the lower investment, the following working fluids for the supercritical ORC system are recommended: R152a and R143a.

  4. Modelling the Influence of Climate on the Performance of the Organic Rankine Cycle for Industrial Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    Ivan Korolija

    2016-05-01

    Full Text Available This paper describes a study of the relative influences of different system design decisions upon the performance of an organic Rankine cycle (ORC used to generate electricity from foundry waste heat. The design choices included concern the working fluid, whether to use a regenerator and the type of condenser. The novelty of the research lies in its inclusion of the influence of both the ORC location and the auxiliary electricity used by the pumps and fans in the ORC power system. Working fluids suitable for high temperature applications are compared, including three cyclic siloxanes, four linear siloxanes and three aromatic fluids. The ORC is modelled from first principles and simulation runs carried out using weather data for 106 European locations and a heat input profile that was derived from empirical data. The impact of design decisions upon ORC nominal efficiency is reported followed by the impact upon annual system efficiency in which variations in heat input and the condition of outdoor air over a year are considered. The main conclusion is that the location can have a significant impact upon the efficiency of ORC systems due to the influence of climate upon the condenser and auxiliary electricity requirements.

  5. Performance of Siloxane Mixtures in a High-Temperature Organic Rankine Cycle Considering the Heat Transfer Characteristics during Evaporation

    Directory of Open Access Journals (Sweden)

    Theresa Weith

    2014-08-01

    Full Text Available The application of the Organic Rankine Cycle to high temperature heat sources is investigated on the case study of waste heat recovery from a selected biogas plant. Two different modes of operation are distinguished: pure electric power and combined heat and power generation. The siloxanes hexamethyldisiloxane (MM and octamethyltrisiloxane (MDM are chosen as working fluids. Moreover, the effect of using mixtures of these components is analysed. Regarding pure electricity generation, process simulations using the simulation tool Aspen Plus show an increase in second law efficiency of 1.3% in case of 97/03 wt % MM/MDM-mixture, whereas for the combined heat and power mode a 60/40 wt % MM/MDM-mixture yields the highest efficiency with an increase of nearly 3% compared to most efficient pure fluid. Next to thermodynamic analysis, measurements of heat transfer coefficients of these siloxanes as well as their mixtures are conducted and Kandlikar’s correlation is chosen to describe the results. Based on that, heat exchanger areas for preheater and evaporator are calculated in order to check whether the poorer heat transfer characteristics of mixtures devalue their efficiency benefit due to increased heat transfer areas. Results show higher heat transfer areas of 0.9% and 14%, respectively, compared to MM.

  6. Exergy analysis of an integrated solid oxide fuel cell and organic Rankine cycle for cooling, heating and power production

    Science.gov (United States)

    Al-Sulaiman, Fahad A.; Dincer, Ibrahim; Hamdullahpur, Feridun

    The study examines a novel system that combined a solid oxide fuel cell (SOFC) and an organic Rankine cycle (ORC) for cooling, heating and power production (trigeneration) through exergy analysis. The system consists of an SOFC, an ORC, a heat exchanger and a single-effect absorption chiller. The system is modeled to produce a net electricity of around 500 kW. The study reveals that there is 3-25% gain on exergy efficiency when trigeneration is used compared with the power cycle only. Also, the study shows that as the current density of the SOFC increases, the exergy efficiencies of power cycle, cooling cogeneration, heating cogeneration and trigeneration decreases. In addition, it was shown that the effect of changing the turbine inlet pressure and ORC pump inlet temperature are insignificant on the exergy efficiencies of the power cycle, cooling cogeneration, heating cogeneration and trigeneration. Also, the study reveals that the significant sources of exergy destruction are the ORC evaporator, air heat exchanger at the SOFC inlet and heating process heat exchanger.

  7. Thermo-Economic Analysis of Zeotropic Mixtures and Pure Working Fluids in Organic Rankine Cycles for Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    Florian Heberle

    2016-03-01

    Full Text Available We present a thermo-economic analysis of an Organic Rankine Cycle (ORC for waste heat recovery. A case study for a heat source temperature of 150 °C and a subcritical, saturated cycle is performed. As working fluids R245fa, isobutane, isopentane, and the mixture of isobutane and isopentane are considered. The minimal temperature difference in the evaporator and the condenser, as well as the mixture composition are chosen as variables in order to identify the most suitable working fluid in combination with optimal process parameters under thermo-economic criteria. In general, the results show that cost-effective systems have a high minimal temperature difference ΔTPP,C at the pinch-point of the condenser and a low minimal temperature difference ΔTPP,E at the pinch-point of the evaporator. Choosing isobutane as the working fluid leads to the lowest costs per unit exergy with 52.0 €/GJ (ΔTPP,E = 1.2 K; ΔTPP,C = 14 K. Considering the major components of the ORC, specific costs range between 1150 €/kW and 2250 €/kW. For the zeotropic mixture, a mole fraction of 90% isobutane leads to the lowest specific costs per unit exergy. A further analysis of the ORC system using isobutane shows high sensitivity of the costs per unit exergy for the selected cost estimation methods and for the isentropic efficiency of the turbine.

  8. Performance of a 250 kW Organic Rankine Cycle System for Off-Design Heat Source Conditions

    Directory of Open Access Journals (Sweden)

    Ben-Ran Fu

    2014-06-01

    Full Text Available An organic Rankine cycle system comprised of a preheater, evaporator, condenser, turbine, generator, and pump was used to study its off-design performance and the operational control strategy. R245fa was used as the working fluid. Under the design conditions, the net power output is 243 kW and the system thermal efficiency is 9.5%. For an off-design heat source flow rate (mW, the operating pressure was controlled to meet the condition that the R245fa reached the liquid and vapor saturation states at the outlet of the preheater and the evaporator, respectively. The analytical results demonstrated that the operating pressure increased with increasing mW; a higher mW yielded better heat transfer performance of the preheater and required a smaller evaporator heat capacity, and the net power output and system thermal efficiency increased with increasing mW. For the range of mW studied here, the net power output increased by 64.0% while the total heat transfer rate increased by only 9.2%. In summary, off-design operation of the system was examined for a heat source flow rate which varied by –39.0% to +78.0% from the designed rate, resulting in –29.2% to +16.0% and –25.3% to +12.6% variations in the net power output and system thermal efficiency, respectively.

  9. Economic assessment of greenhouse gas reduction through low-grade waste heat recovery using organic Rankine cycle (ORC)

    Energy Technology Data Exchange (ETDEWEB)

    Imran, Muhammad; Park, Byung Sik; Kim, Hyouck Ju; Usman, Muhammad [University of Science and Technology, Daejeon (Korea, Republic of); Lee, Dong Hyun [Korea Institute of Energy Research, Daejeon (Korea, Republic of)

    2015-02-15

    Low-grade waste heat recovery technologies reduce the environmental impact of fossil fuels and improve overall efficiency. This paper presents the economic assessment of greenhouse gas (GHG) reduction through waste heat recovery using organic Rankine cycle (ORC). The ORC engine is one of the mature low temperature heat engines. The low boiling temperature of organic working fluid enables ORC to recover low-temperature waste heat. The recovered waste heat is utilized to produce electricity and hot water. The GHG emissions for equivalent power and hot water from three fossil fuels-coal, natural gas, and diesel oil-are estimated using the fuel analysis approach and corresponding emission factors. The relative decrease in GHG emission is calculated using fossil fuels as the base case. The total cost of the ORC system is used to analyze the GHG reduction cost for each of the considered fossil fuels. A sensitivity analysis is also conducted to investigate the effect of the key parameter of the ORC system on the cost of GHG reduction. Throughout the 20-year life cycle of the ORC plant, the GHG reduction cost for R245fa is 0.02 $/kg to 0.04 $/kg and that for pentane is 0.04 $/kg to 0.05 $/kg. The working fluid, evaporation pressure, and pinch point temperature difference considerably affect the GHG emission.

  10. Technical Analysis of Organic Rankine Cycle System Using Low-Temperature Source to Generate Electricity in Ship

    Directory of Open Access Journals (Sweden)

    Akram Faisal

    2017-01-01

    Full Text Available Nowadays, the shipping sector has growth rapidly as followed by the increasing of world population and the demands for public transportation via sea. This issue entails the large attention on emission, energy efficiency and fuel consumption on the ship. Waste Heat Recovery (WHR is one of the solution to overcome the mentioned issue and one of the WHR method is by installing Organic Rankine Cycle (ORC system in ship. ORC demonstrate to recover and exploit the low temperature waste heat rejected by the ship power generation plant. The main source of heat to be utilized is obtained from container ship (7900 kW BHP, DWT 10969 mt ship jacket water cooling system and use R-134a as a refrigerant. The main equipment consists of evaporator, condenser, pump and steam turbine to generate the electricity. The main objective is to quantifying the estimation of electrical power which can be generated at typical loads of the main engine. As the final result of analysis, the ORC system is able to generate the electricity power ranged from 77,5% - 100% of main engine load producing power averagely 57,69 kW.

  11. Parametric-Based Thermodynamic Analysis of Organic Rankine Cycle as Bottoming Cycle for Combined-Cycle Power Plant

    Directory of Open Access Journals (Sweden)

    SAMIULLAH QURESHI

    2017-01-01

    Full Text Available In Pakistan, the thermal efficiency of the power plants is low because of a huge share of fuel energy is dumped into the atmosphere as waste heat. The ORC (Organic Rankine Cycle has been revealed as one of the promising technologies to recover waste heat to enhance the thermal efficiency of the power plant. In current work, ORC is proposed as a second bottoming cycle for existing CCPP (Combined Cycle Power Plant. In order to assess the efficiency of the plant, a thermodynamic model is developed in the ESS (Engineering Equation Solver software. The developed model is used for parametric analysis to assess the effects of various operating parameters on the system performance. The analysis of results shows that the integration of ORC system with existing CCPP system enhances the overall power output in the range of 150.5-154.58 MW with 0.24-5% enhancement in the efficiency depending on the operating conditions. During the parametric analysis of ORC, it is observed that inlet pressure of the turbine shows a significant effect on the performance of the system as compared to other operating parameters.

  12. Studi Eksperimen Perbandingan Pengaruh Variasi Tekanan Inlet Turbin danVariasi Pembebanan Terhadap Karakteristik Turbin Pada Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Dwi Dharma Risqiawan

    2013-12-01

    Full Text Available Sistem pembangkit listrik telah berinovasi pada saat ini untuk tetap memenuhi kebutuhan akan ketersediaan listrik salah satunya dengan Organic Rankine Cycle (ORC. Sistem ini terdiri dari empat komponen utama yaitu evaporator, turbin, kondensor, dan pompa.Fluida kerja dipompa ke evaporator untuk membangkitkan uap lalu digunakan menggerakkan turbin.Uap hasil ekspansi turbin dikondensasi dan dialirkan oleh pompa kembali ke evaporator.Sistem ini mampu memanfaatkan sumber energi yang memiliki temperatur dan tekanan rendah untuk membangkitkan uap fluida organik. Penelitian ini dilakukan untuk mengevaluasi kinerja turbin pada sistem ORC dengan memvariasikan tekanan masuk turbin dan pembebanan dengan menggunakan R-123 sebagai fluida kerja .Pengambilan data dilakukan dengan memvariasikan tekanan masuk turbin pada setiap variasi pembebanan generator.Pengamatan dilakukan hanya pada turbin untuk mengetahui karakteristik turbin yang digunakan saat ini.Pengambilan data dilakukan dengan R-123 sebagai fluida kerja. Dari eksperimen didapatkan temperatur masuk dan keluar turbin,kecepatan putaran turbin dalam rpm, dan enthalpy dapat diketahui. Enthalpy digunakan untuk mengitung kerja yang dihasilkan turbin, efisiensi turbin dan efisiensi sudu turbin.Pada tekanan masuk turbin 8 bar dan beban 1000 Watt data dengan nilai terbaik didapatkan.Hasil perhitungan data didapatkan kerja yang dihasilkan turbin yang terbesar adalah 5,4 KW. Hasil lain yang dapat diketahui adalah efisiensi turbin tertinggi 88%. Efisiensi sudu turbin tertinggi yang terhitung adalah 42,9%.

  13. An Innovative Application of a Solar Storage Wall Combined with the Low-Temperature Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Tzu-Chen Hung

    2014-01-01

    Full Text Available The objective of this study is to collect energy on the waste heat from air produced by solar ventilation systems. This heat used for electricity generation by an organic Rankine cycle (ORC system was implemented. The advantages of this method include the use of existing building’s wall, and it also provides the region of energy scarcity for reference. This is also an innovative method, and the results will contribute to the efforts made toward improving the design of solar ventilation in the field of solar thermal engineering. In addition, ORC system would help generate electricity and build a low-carbon building. This study considered several critical parameters such as length of the airflow channel, intensity of solar radiation, pattern of the absorber plate, stagnant air layer, and operating conditions. The simulation results show that the highest outlet temperature and heat collecting efficiency of solar ventilation system are about 120°C and 60%, respectively. The measured ORC efficiency of the system was 6.2%. The proposed method is feasible for the waste heat from air produced by ventilation systems.

  14. THERMODYNAMIC ANALYSIS OF DIFFERENT WORKING FLUIDS USED IN ORGANIC RANKINE CYCLE FOR RECOVERING WASTE HEAT FROM GT-MHR

    Directory of Open Access Journals (Sweden)

    AMIN HABIBZADEH

    2016-01-01

    Full Text Available In this paper, the performance of 13 working fluids in two Organic Rankine Cycles, which operate as the bottoming cycles for recovering waste heat from gas turbine modular helium reactor (GT-MHR, is investigated. Working fluids are classified in three dry, isentropic and wet fluids. The effect of varying pump temperature and evaporator pressure on the thermal efficiency, total exergy loss of the combined cycle is studied for each category, and the results are compared. The results are calculated for an optimum pressure ratio in which thermal efficiency is maximum. According to the results, dry fluids show a higher thermal efficiency while wet fluids have the lowest values. However, the highest value for thermal efficiency is for R141b, which is an isentropic fluid. Furthermore, the results indicate that pump temperature increase, reduces the total thermal efficiency and increases the total exergy loss of the combined cycle. Increasing evaporator pressure leads to an optimum pressure that maximizes total thermal efficiency. According to the optimized pressure ratio and evaporator pressure, R141b in isentropic fluids, R123 in dry fluids and R717 in wet fluids have the highest thermal efficiency values.

  15. Study on Mixed Working Fluids with Different Compositions in Organic Rankine Cycle (ORC Systems for Vehicle Diesel Engines

    Directory of Open Access Journals (Sweden)

    Kai Yang

    2014-08-01

    Full Text Available One way to increase the thermal efficiency of vehicle diesel engines is to recover waste heat by using an organic Rankine cycle (ORC system. Tests were conducted to study the running performances of diesel engines in the whole operating range. The law of variation of the exhaust energy rate under various engine operating conditions was also analyzed. A diesel engine-ORC combined system was designed, and relevant evaluation indexes proposed. The variation of the running performances of the combined system under various engine operating conditions was investigated. R245fa and R152a were selected as the components of the mixed working fluid. Thereafter, six kinds of mixed working fluids with different compositions were presented. The effects of mixed working fluids with different compositions on the running performances of the combined system were revealed. Results show that the running performances of the combined system can be improved effectively when mass fraction R152a in the mixed working fluid is high and the engine operates with high power. For the mixed working fluid M1 (R245fa/R152a, 0.1/0.9, by mass fraction, the net power output of the combined system reaches the maximum of 34.61 kW. Output energy density of working fluid (OEDWF, waste heat recovery efficiency (WHRE, and engine thermal efficiency increasing ratio (ETEIR all reach their maximum values at 42.7 kJ/kg, 10.90%, and 11.29%, respectively.

  16. Performance of a reversible heat pump/organic Rankine cycle unit coupled with a passive house to get a positive energy building

    DEFF Research Database (Denmark)

    Dumont, Olivier; Carmo, Carolina; Fontaine, Valentin;

    2016-01-01

    and generate electricity, coupled to a solar thermal collector roof. This reversible HP/organic Rankine cycle unit presents three operating modes: direct heating, HP and organic Rankine cycle. This work focuses on describing the dynamic model of the multi-component system followed by a techno-economic analysis...... of the system under different operational conditions. Sensitivity studies include: building envelope, climate, appliances, lighting and heat demand profiles. It is concluded that the HP/ORC unit can turn a single-family house into a PEB under certain weather conditions (electrical production of 3012 k......Wh/year and total electrical consumption of 2318 kWh/year) with a 138.8 m2 solar roof in Denmark....

  17. Preliminary Development of a Free Piston Expander–Linear Generator for Small-Scale Organic Rankine Cycle (ORC) Waste Heat Recovery System

    OpenAIRE

    Gaosheng Li; Hongguang Zhang; Fubin Yang; Songsong Song; Ying Chang; Fei Yu; Jingfu Wang; Baofeng Yao

    2016-01-01

    A novel free piston expander-linear generator (FPE-LG) integrated unit was proposed to recover waste heat efficiently from vehicle engine. This integrated unit can be used in a small-scale Organic Rankine Cycle (ORC) system and can directly convert the thermodynamic energy of working fluid into electric energy. The conceptual design of the free piston expander (FPE) was introduced and discussed. A cam plate and the corresponding valve train were used to control the inlet and outlet valve timi...

  18. System and component modelling and optimisation for an efficient 10 kWe low-temperature organic Rankine cycle utilising a radial inflow expander

    OpenAIRE

    2015-01-01

    Small-scale (10 kWe) organic Rankine cycles for low temperature applications such as heat recovery and solar power present a significant development opportunity but limited prototypes have been developed. This paper aims to address this by describing a system modelling tool which is used to select a working fluid, optimise cycle conditions, and preliminarily size a radial inflow rotor for an experimental test rig. The program is a steady-state sizing and optimisation tool which advances on cu...

  19. Final Report: Modifications and Optimization of the Organic Rankine Cycle to Improve the Recovery of Waste Heat

    Energy Technology Data Exchange (ETDEWEB)

    Donna Post Guillen; Jalal Zia

    2013-09-01

    This research and development (R&D) project exemplifies a shared public private commitment to advance the development of energy efficient industrial technologies that will reduce the U.S. dependence upon foreign oil, provide energy savings and reduce greenhouse gas emissions. The purpose of this project was to develop and demonstrate a Direct Evaporator for the Organic Rankine Cycle (ORC) for the conversion of waste heat from gas turbine exhaust to electricity. In conventional ORCs, the heat from the exhaust stream is transferred indirectly to a hydrocarbon based working fluid by means of an intermediate thermal oil loop. The Direct Evaporator accomplishes preheating, evaporation and superheating of the working fluid by a heat exchanger placed within the exhaust gas stream. Direct Evaporation is simpler and up to 15% less expensive than conventional ORCs, since the secondary oil loop and associated equipment can be eliminated. However, in the past, Direct Evaporation has been avoided due to technical challenges imposed by decomposition and flammability of the working fluid. The purpose of this project was to retire key risks and overcome the technical barriers to implementing an ORC with Direct Evaporation. R&D was conducted through a partnership between the Idaho National Laboratory (INL) and General Electric (GE) Global Research Center (GRC). The project consisted of four research tasks: (1) Detailed Design & Modeling of the ORC Direct Evaporator, (2) Design and Construction of Partial Prototype Direct Evaporator Test Facility, (3) Working Fluid Decomposition Chemical Analyses, and (4) Prototype Evaluation. Issues pertinent to the selection of an ORC working fluid, along with thermodynamic and design considerations of the direct evaporator, were identified. The FMEA (Failure modes and effects analysis) and HAZOP (Hazards and operability analysis) safety studies performed to mitigate risks are described, followed by a discussion of the flammability analysis of the

  20. Study Analysis of Flue Gas Utilization as Alternative Power Generation in Cement Plant Using Organic Rankine Cycle System

    Directory of Open Access Journals (Sweden)

    Rahmat Ranggonang Anwar

    2017-01-01

    Full Text Available Abstract—Cement plant produce large amount of heat source in cement making process, due to inefficiency of system there still waste heat available in form of flue gas that can be utilize. Flue gas  in cement plant can be utilized as alternative power generation. With the 200-300oC temperature output range of flue gas from suspension preheater and air quenching cooler (AQC in cement plant, organic rankine cycle (ORC can be suitable option for alternative power generation. ORC is development of rankine cycle, the different is the working fluid in ORC using refrigerant. In cement plant that produce 8466 TPD kiln production, used flue gas from suspension preheater to dry raw material and produce 163888 m3/h flue gas from AQC that still not utilized. Flue gas with 235oC temperature from AQC can utilized for power generation purpose using ORC system. Waste heat recovery calculation carried out to know the potential recovery. Operating condition of the ORC system will determine power produced that can be generated and ORC components calculated and selected according to the operating condition of the system. Using R141b as working fluid with 8 bar pressure and 110oC temperature inlet to turbine, power produced by turbine is 666 kW. For the components, evaporator and condenser use shell and tube heat exchanger, with evaporator heat transfer area is 676.49 m2 while condenser has 510 m2 of heat transfer area. And for working fluid pump it needs 16.235 Kw power to pump R141b back to evaporator.

  1. Comparison of a Novel Organic-Fluid Thermofluidic Heat Converter and an Organic Rankine Cycle Heat Engine

    Directory of Open Access Journals (Sweden)

    Christoph J.W. Kirmse

    2016-06-01

    Full Text Available The Up-THERM heat converter is an unsteady, two-phase thermofluidic oscillator that employs an organic working fluid, which is currently being considered as a prime-mover in small- to medium-scale combined heat and power (CHP applications. In this paper, the Up-THERM heat converter is compared to a basic (sub-critical, non-regenerative organic Rankine cycle (ORC heat engine with respect to their power outputs, thermal efficiencies and exergy efficiencies, as well as their capital and specific costs. The study focuses on a pre-specified Up-THERM design in a selected application, a heat-source temperature range from 210 °C to 500 °C and five different working fluids (three n-alkanes and two refrigerants. A modeling methodology is developed that allows the above thermo-economic performance indicators to be estimated for the two power-generation systems. For the chosen applications, the power output of the ORC engine is generally higher than that of the Up-THERM heat converter. However, the capital costs of the Up-THERM heat converter are lower than those of the ORC engine. Although the specific costs (£/kW of the ORC engine are lower than those of the Up-THERM converter at low heat-source temperatures, the two systems become progressively comparable at higher temperatures, with the Up-THERM heat converter attaining a considerably lower specific cost at the highest heat-source temperatures considered.

  2. Energy and Exergy Analyses of a Combined Power Cycle Using the Organic Rankine Cycle and the Cold Energy of Liquefied Natural Gas

    OpenAIRE

    2015-01-01

    In this work, energy and exergy analyses are carried out for a combined cycle consisting of an organic Rankine cycle (ORC) and a liquefied natural gas (LNG) Rankine cycle for the recovery of low-grade heat sources and LNG cold energy. The effects of the turbine inlet pressure and the working fluid on the system performance are theoretically investigated. A modified temperature-enthalpy diagram is proposed, which can be useful to see the characteristics of the combined cycle, as well as the te...

  3. Design and development of an automotive organic Rankine-cycle powerplant with a reciprocating expander. Final report. Volume II. Detailed discussion

    Energy Technology Data Exchange (ETDEWEB)

    1977-09-01

    Work performed for the design and development of an organic Rankine-cycle engine for automobile propulsion is reported. An automotive power plant using an organic Rankine-cycle system with a reciprocating expander has been designed, built, and tested on an engine dynamometer in a preprototype configuration. The system is designed to provide performance approximately equivalent to that of a 351-CID internal combustion engine in the reference car, a 1972 Ford Galaxie 500. A description of the preprototype system, major components, and results from component and system testing are presented. The fuel economy based on steady-state measurements is estimated to be 10.2 mpg over the federal driving cycle with a maximum of 16 mpg at 30 mph. Projections of steady-state emission measurements show compliance with the 1970 Clean Air Act standards for 1978 vehicle emissions. The levels for unburned hydrocarbons, carbon monoxide, and oxides of nitrogen were 41 percent, 6 percent, and 69 percent of the standards, respectively. At the conclusion of the preprototype phase of the program, a prototype design effort was initiated to upgrade and improve the performance of the preprototype system. The reference vehicle for this prototype design is a compact car in the weight class of a 1974 Ford Pinto. The results of this design study, including performance projections, are also presented.

  4. A Mathematical Model of Hourly Solar Radiation in Varying Weather Conditions for a Dynamic Simulation of the Solar Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Taehong Sung

    2015-07-01

    Full Text Available A mathematical model of hourly solar radiation with weather variability is proposed based on the simple sky model. The model uses a superposition of trigonometric functions with short and long periods. We investigate the effects of the model variables on the clearness (kD and the probability of persistence (POPD indices and also evaluate the proposed model for all of the kD-POPD weather classes. A simple solar organic Rankine cycle (SORC system with thermal storage is simulated using the actual weather conditions, and then, the results are compared with the simulation results using the proposed model and the simple sky model. The simulation results show that the proposed model provides more accurate system operation characteristics than the simple sky model.

  5. Performance Evaluation of a HP/ORC (Heat Pump/Organic Rankine Cycle) System with Optimal Control of Sensible Thermal Storage

    DEFF Research Database (Denmark)

    Carmo, Carolina; Nielsen, Mads P.; Elmegaard, Brian

    2016-01-01

    In energy systems with high share of renewable energy sources, like wind and solar power, it is paramount to deal with their intrinsic variability. The interaction between electric and thermal energy (heating and cooling) demands representa potential area for balancing supply and demand that could...... of the users. Results show that real load control logic can lessen the adverse effects ofcycling in the compressor of the system as well as increase the thermal demand (up to 33%) and the electrical demand (max. 8.4%) covered by renewable energy (solar). However, the extension of these improvements is highly...... come to contribute to the integration of intermittent renewables.This paper describes an innovative concept that consists of the addition of an Organic Rankine Cycle (ORC) toa combined solar system coupled to a ground-source heat pump (HP) in a single-family building. The ORC enables the use of solar...

  6. Comparison of Cooling System Designs for an Exhaust Heat Recovery System Using an Organic Rankine Cycle on a Heavy Duty Truck

    Directory of Open Access Journals (Sweden)

    Nicolas Stanzel

    2016-11-01

    Full Text Available A complex simulation model of a heavy duty truck, including an Organic Rankine Cycle (ORC based waste heat recovery system and a vehicle cooling system, was applied to determine the system fuel economy potential in a typical drive cycle. Measures to increase the system performance were investigated and a comparison between two different cooling system designs was derived. The base design, which was realized on a Mercedes-Benz Actros vehicle revealed a fuel efficiency benefit of 2.6%, while a more complicated design would generate 3.1%. Furthermore, fully transient simulation results were performed and are compared to steady state simulation results. It is shown that steady state simulation can produce comparable results if averaged road data are used as boundary conditions.

  7. Flow boiling heat transfer and pressure drop characteristics of R134a, R1234yf and R1234ze in a plate heat exchanger for organic Rankine cycle units

    DEFF Research Database (Denmark)

    Zhang, Ji; Desideri, Adriano; Kærn, Martin Ryhl

    2017-01-01

    . This paper is aimed at obtaining flow boiling heat transfer and pressure drop characteristics in a plate heat exchanger under the working conditions prevailing in the evaporator of organic Rankine cycle units. Two hydrofluoroolefins R1234yf and R1234ze, and one hydrofluorocarbon R134a, were selected...

  8. 有机朗肯循环系统变工况特性分析%Analysis of organic Rankine's cycle in the variable working condition

    Institute of Scientific and Technical Information of China (English)

    林红良; 付保荣

    2014-01-01

    Organic Rankine's cycle power generation system internal parameters closely related to the external environment, the change of heat source parameters, cooling water temperature fluctuations can cause various points within the system parameter change, resulting in power system operation for a long time in the rating system thermal efficiency is low. Based on cyclic working substance of R245fa organic Rankine's cycle as the research object, through the establishment of evaporator and condenser heat transfer model, it is concluded that organic Rankine's circulation in different heat source temperature, evaporation temperature, condensation temperature of cooling water temperature changes, thereby gaining evaporation temperature, condensation temperature and the function relation between the heat source temperature, cooling water temperature. In actual organic Rankine's circulation waste heat power generation project, there are many unstable factors, so the analysis of the organic Rankine's circulation the variable working condition characteristics is necessary, to improve overall system performance has guiding significance.%有机朗肯循环系统发电系统内部参数与外界环境紧密相关,热源参数的变化、冷却水温度的变化都会使得系统内部各个点参数改变,从而导致系统长期运行在非额定工况热效率低。该文以循环工质为R245fa的有机朗肯循环系统作为研究对象,通过建立蒸发器和冷凝器换热模型,得出有机朗肯循环系统在不同热源温度、不同冷却水温度下的最佳蒸发温度、凝结温度变化情况,从而获得蒸发温度、凝结温度与热源温度、冷却水温度之间的函数关系。在实际有机朗肯循环系统余热发电工程中,存在着很多不稳定因素,因此对有机朗肯循环系统变工况特性分析是非常有必要的,对于提高系统整体性能具有指导性意义。

  9. Effects of Degree of Superheat on the Running Performance of an Organic Rankine Cycle (ORC Waste Heat Recovery System for Diesel Engines under Various Operating Conditions

    Directory of Open Access Journals (Sweden)

    Kai Yang

    2014-04-01

    Full Text Available This study analyzed the variation law of engine exhaust energy under various operating conditions to improve the thermal efficiency and fuel economy of diesel engines. An organic Rankine cycle (ORC waste heat recovery system with internal heat exchanger (IHE was designed to recover waste heat from the diesel engine exhaust. The zeotropic mixture R416A was used as the working fluid for the ORC. Three evaluation indexes were presented as follows: waste heat recovery efficiency (WHRE, engine thermal efficiency increasing ratio (ETEIR, and output energy density of working fluid (OEDWF. In terms of various operating conditions of the diesel engine, this study investigated the variation tendencies of the running performances of the ORC waste heat recovery system and the effects of the degree of superheat on the running performance of the ORC waste heat recovery system through theoretical calculations. The research findings showed that the net power output, WHRE, and ETEIR of the ORC waste heat recovery system reach their maxima when the degree of superheat is 40 K, engine speed is 2200 r/min, and engine torque is 1200 N·m. OEDWF gradually increases with the increase in the degree of superheat, which indicates that the required mass flow rate of R416A decreases for a certain net power output, thereby significantly decreasing the risk of environmental pollution.

  10. Energy and Exergy Analyses of a Combined Power Cycle Using the Organic Rankine Cycle and the Cold Energy of Liquefied Natural Gas

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    Ho Yong Lee

    2015-09-01

    Full Text Available In this work, energy and exergy analyses are carried out for a combined cycle consisting of an organic Rankine cycle (ORC and a liquefied natural gas (LNG Rankine cycle for the recovery of low-grade heat sources and LNG cold energy. The effects of the turbine inlet pressure and the working fluid on the system performance are theoretically investigated. A modified temperature-enthalpy diagram is proposed, which can be useful to see the characteristics of the combined cycle, as well as the temperature distributions in the heat exchangers. Results show that the thermal efficiency increases with an increasing turbine inlet pressure and critical temperature of the working fluid. However, the exergy efficiency has a peak value with respect to the turbine inlet pressure, and the maximum exergy efficiency and the corresponding optimum turbine inlet pressure are significantly influenced by the selection of the working fluid. The exergy destruction at the condenser is generally the greatest among the exergy destruction components of the system.

  11. Milestone Report #2: Direct Evaporator Leak and Flammability Analysis Modifications and Optimization of the Organic Rankine Cycle to Improve the Recovery of Waste Heat

    Energy Technology Data Exchange (ETDEWEB)

    Donna Post Guillen

    2013-09-01

    The direct evaporator is a simplified heat exchange system for an Organic Rankine Cycle (ORC) that generates electricity from a gas turbine exhaust stream. Typically, the heat of the exhaust stream is transferred indirectly to the ORC by means of an intermediate thermal oil loop. In this project, the goal is to design a direct evaporator where the working fluid is evaporated in the exhaust gas heat exchanger. By eliminating one of the heat exchangers and the intermediate oil loop, the overall ORC system cost can be reduced by approximately 15%. However, placing a heat exchanger operating with a flammable hydrocarbon working fluid directly in the hot exhaust gas stream presents potential safety risks. The purpose of the analyses presented in this report is to assess the flammability of the selected working fluid in the hot exhaust gas stream stemming from a potential leak in the evaporator. Ignition delay time for cyclopentane at temperatures and pressure corresponding to direct evaporator operation was obtained for several equivalence ratios. Results of a computational fluid dynamic analysis of a pinhole leak scenario are given.

  12. Preliminary Development of a Free Piston Expander–Linear Generator for Small-Scale Organic Rankine Cycle (ORC Waste Heat Recovery System

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    Gaosheng Li

    2016-04-01

    Full Text Available A novel free piston expander-linear generator (FPE-LG integrated unit was proposed to recover waste heat efficiently from vehicle engine. This integrated unit can be used in a small-scale Organic Rankine Cycle (ORC system and can directly convert the thermodynamic energy of working fluid into electric energy. The conceptual design of the free piston expander (FPE was introduced and discussed. A cam plate and the corresponding valve train were used to control the inlet and outlet valve timing of the FPE. The working principle of the FPE-LG was proven to be feasible using an air test rig. The indicated efficiency of the FPE was obtained from the p–V indicator diagram. The dynamic characteristics of the in-cylinder flow field during the intake and exhaust processes of the FPE were analyzed based on Fluent software and 3D numerical simulation models using a computation fluid dynamics method. Results show that the indicated efficiency of the FPE can reach 66.2% and the maximal electric power output of the FPE-LG can reach 22.7 W when the working frequency is 3 Hz and intake pressure is 0.2 MPa. Two large-scale vortices are formed during the intake process because of the non-uniform distribution of velocity and pressure. The vortex flow will convert pressure energy and kinetic energy into thermodynamic energy for the working fluid, which weakens the power capacity of the working fluid.

  13. Organic Rankine Cycle for Residual Heat to Power Conversion in Natural Gas Compressor Station. Part II: Plant Simulation and Optimisation Study

    Science.gov (United States)

    Chaczykowski, Maciej

    2016-06-01

    After having described the models for the organic Rankine cycle (ORC) equipment in the first part of this paper, this second part provides an example that demonstrates the performance of different ORC systems in the energy recovery application in a gas compressor station. The application shows certain specific characteristics, i.e. relatively large scale of the system, high exhaust gas temperature, low ambient temperature operation, and incorporation of an air-cooled condenser, as an effect of the localization in a compressor station plant. Screening of 17 organic fluids, mostly alkanes, was carried out and resulted in a selection of best performing fluids for each cycle configuration, among which benzene, acetone and heptane showed highest energy recovery potential in supercritical cycles, while benzene, toluene and cyclohexane in subcritical cycles. Calculation results indicate that a maximum of 10.4 MW of shaft power can be obtained from the exhaust gases of a 25 MW compressor driver by the use of benzene as a working fluid in the supercritical cycle with heat recuperation. In relation to the particular transmission system analysed in the study, it appears that the regenerative subcritical cycle with toluene as a working fluid presents the best thermodynamic characteristics, however, require some attention insofar as operational conditions are concerned.

  14. Comparative analysis of CO2-based transcritical Rankine cycle and HFC245fa-based subcritical organic Rankine cycle using low-temperature geothermal source

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A detailed thermodynamic and techno-economic comparison is presented for a CO2-based transcritical Rankine cycle and a subcritical organic Rankine cycle (ORC) using HFC245fa (1,1,1,3,3-pentafluoro-propane) as the working fluid driven by the low-temperature geothermal source,in order to determine the configuration that presents the maximum net power output with a minimum investment.The evaluations of both Rankine cycles have been performed based on equal thermodynamic mean heat rejection temperature by varying certain system operating parameters to achieve each Rankine cycle’s optimum design at various geothermal source temperature levels ranging from 80oC to 120oC.The results obtained show that the optimum ther-modynamic mean heat injection temperatures of both Rankine cycles are distributed in the scope of 55% to 65% of a given geothermal source temperature level,and that the CO2-based transcritical Rankine cycle presents 3% to 7% higher net power output,84% reduction of turbine inlet volume flow rate,47% reduction of expansion ratio and 1.68 times higher total heat transfer capacity compared with the HFC245fa-based subcritical ORC.It is also indicated that using the CO2-based transcritical system can reduce the dimension of turbine design.However,it requires larger heat transfer areas with higher strength heat exchanger materials because of the higher system pressure.

  15. Analyzing the Performance of a Dual Loop Organic Rankine Cycle System for Waste Heat Recovery of a Heavy-Duty Compressed Natural Gas Engine

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    Baofeng Yao

    2014-11-01

    Full Text Available A dual loop organic Rankine cycle (DORC system is designed to recover waste heat from a heavy-duty compressed natural gas engine (CNGE, and the performance of the DORC–CNGE combined system is simulated and discussed. The DORC system includes high-temperature (HT and low-temperature (LT cycles. The HT cycle recovers energy from the exhaust gas emitted by the engine, whereas the LT cycle recovers energy from intake air, engine coolant, and the HT cycle working fluid in the preheater. The mathematical model of the system is established based on the first and second laws of thermodynamics. The characteristics of waste heat energy from the CNGE are calculated according to engine test data under various operating conditions. Moreover, the performance of the DORC–CNGE combined system is simulated and analyzed using R245fa as the working fluid. Results show that the maximum net power output and the maximum thermal efficiency of the DORC system are 29.37 kW and 10.81%, respectively, under the rated power output condition of the engine. Compared with the original CNG engine, the maximum power output increase ratio and the maximum brake specific fuel consumption improvement ratio are 33.73% and 25%, respectively, in the DORC–CNGE combined system.

  16. Modeling and Experimental Validation of a Volumetric Expander Suitable for Waste Heat Recovery from an Automotive Internal Combustion Engine Using an Organic Rankine Cycle with Ethanol

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    José Galindo

    2016-04-01

    Full Text Available Waste heat recovery (WHR in exhaust gas flow of automotive engines has proved to be a useful path to increase the overall efficiency of internal combustion engines (ICE. Recovery potentials of up to 7% are shown in several works in the literature. However, most of them are theoretical estimations. Some present results from prototypes fed by steady flows generated in an auxiliary gas tank and not with actual engine exhaust gases. This paper deals with the modeling and experimental validation of an organic Rankine cycle (ORC with a swash-plate expander integrated in a 2 L turbocharged petrol engine using ethanol as working fluid. A global simulation model of the ORC was developed with a maximum difference of 5%, validated with experimental results. Considering the swash-plate as the main limiting factor, an additional specific submodel was implemented to model the physical phenomena in this element. This model allows simulating the fluid dynamic behavior of the swash-plate expander using a 0D model (Amesim. Differences up to 10.5% between tests and model results were found.

  17. Engine Waste Heat Recovery Based on Organic Rankine Cycle%基于有机朗肯循环的发动机余热回收技术

    Institute of Scientific and Technical Information of China (English)

    郭丽华; 覃峰; 陈江平; 刘杰

    2012-01-01

    Eight kinds of cycle media in organic Rankine cycle (ORC) were compared during the thermodynamic process. Considering the systemic, reliable and environmental factors, R245fa was the optimum selection for ORC. For the application of Cummins heavy duty vehicle engine, the power generation system with the waste heat recovery was designed. Recovering the heat from charge air, tail pipe gas and exhaust gas, the power generation was realized. The efficiency of waste heat recovery in the system was 10. 4%.%通过比较8种循环工质在有机朗肯循环(ORC)系统中的热力过程,从系统性能、可靠性、环保等角度综合考虑,验证了R245fa用于ORC循环工质的优势.以康明斯某重型车用发动机为应用目标,设计了一套余热回收发电系统,通过回收增压空气、尾管废气、发动机废气的热量,用于发电.经过计算,该系统的余热回收效率为10.4%.

  18. Part-Load Performance Prediction and Operation Strategy Design of Organic Rankine Cycles with a Medium Cycle Used for Recovering Waste Heat from Gaseous Fuel Engines

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    Xuan Wang

    2016-07-01

    Full Text Available The Organic Rankine Cycle (ORC is regarded as a suitable way to recover waste heat from gaseous fuel internal combustion engines. As waste heat recovery systems (WHRS have always been designed based on rated working conditions, while engines often work under part-load conditions, it is quite significant to analyze the part-load performance and corresponding operation strategy of ORC systems. This paper presents a dynamic model of ORC with a medium cycle used for a large gaseous fuel engine and analyzes the effect of adjustable parameters on the system performance, giving effective control directions under various conditions. The results indicate that the intermediary fluid mass flow rate has nearly no effect on the output power and thermal efficiency of the ORC, while the mass flow rate of working fluid has a great effect on them. In order to get a better system performance under different working conditions, the system should be operated with the working fluid mass flow rate as large as possible, but with a slight degree of superheating. Then, with the control of constant superheat degree at the end of the heating process, the performance of the combined system that consists of ORC and the engine at steady state under seven typical working conditions is also analyzed. The results indicate that the energy-saving effect of WHRS becomes worse and worse as the working condition decreases. Especially at 40% working condition the WHRS nearly has no energy-saving effect anymore.

  19. Parametric and exergetic analysis of a two-stage transcritical combined organic Rankine cycle used for multiple grades waste heat recovery of diesel engine

    Science.gov (United States)

    Tian, H.; Zhang, J.; Xu, X. F.; Shu, G. Q.; Wei, H. Q.

    2013-12-01

    Diesel engine has multiple grades of waste heat with different ratios of combustion heat, exhaust is 400 °C with the ratio of 21% and coolant is 90 °C with 19%. Few previous publications investigate the recovery of multiple grades waste heat together. In this paper, a two-stage transcritical combined organic rankine cycle (CORC) is presented and analyzed. In the combined system, the high and low temperature stages transcritical cycle recover the high grades waste heat, and medium to low grades waste heat respectively, and being combined efficiently. Meanwhile, the suitable working fluids for high stage are chosen and analyzed. The cycle parameters, including thermal efficiency (ηth), net power output (Pnet), energy efficiency (ηexg) and global thermal efficiency of DE-CORC(ηglo) have also been analyzed and optimized. The results indicate that this combined system could recover all the waste heat with a high recovery ratio (above 90%) and obtain a maximum power output of 37kW for a DE of 243kW. The global thermal efficiency of DE-CORC can get a max value of 46.2% compared with 40% for single DE. The results also indicate that all the energy conversion process have a high exergy efficiency.

  20. Optimization of Biomass-Fuelled Combined Cooling, Heating and Power (CCHP Systems Integrated with Subcritical or Transcritical Organic Rankine Cycles (ORCs

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    Daniel Maraver

    2014-04-01

    Full Text Available This work is focused on the thermodynamic optimization of Organic Rankine Cycles (ORCs, coupled with absorption or adsorption cooling units, for combined cooling heating and power (CCHP generation from biomass combustion. Results were obtained by modelling with the main aim of providing optimization guidelines for the operating conditions of these types of systems, specifically the subcritical or transcritical ORC, when integrated in a CCHP system to supply typical heating and cooling demands in the tertiary sector. The thermodynamic approach was complemented, to avoid its possible limitations, by the technological constraints of the expander, the heat exchangers and the pump of the ORC. The working fluids considered are: n-pentane, n-heptane, octamethyltrisiloxane, toluene and dodecamethylcyclohexasiloxane. In addition, the energy and environmental performance of the different optimal CCHP plants was investigated. The optimal plant from the energy and environmental point of view is the one integrated by a toluene recuperative ORC, although it is limited to a development with a turbine type expander. Also, the trigeneration plant could be developed in an energy and environmental efficient way with an n-pentane recuperative ORC and a volumetric type expander.

  1. Studi Numerik Dua Dimensi Labyrinth Seal Turbin Uap Organic Rankine Cycle (ORC Type Straight-Through dengan Variasi Tekanan Inlet, Kecepatan Putaran Poros, Jarak Pitch, dan Tinggi Rongga

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    Fungki Setyo Yulianto

    2013-03-01

    Full Text Available ORC (Organic Rankine Cycle merupakan salah satu sistem pembangkit tenaga yang mampu memanfaatkan waste energy dengan menggunakan fluida organik yang mampu menguap pada temperatur dan tekanan rendah. Salah satu komponen utama pada sistem ORC adalah Turbin. Untuk mendapatkan efisiensi yang maksimal,  kebocoran fluida pada turbin uap harus di minimalisir. Untuk itulah di perlukan penggunaan labyrinth seal untuk mengurai kebocoran fluida R123 pada turbin uap ORC. Pada dunia Industri jenis labyrinth seal sangat banyak sekali, salah satunya adalah labyrinth seal tipe Straight-Through. Penelitian ini dilakukan dengan metode numerik (CFD software Fluent. Penelitian ini menggunakan variasi tekanan inlet yaitu 5, 10 dan 15 bar, putaran poros 0, 1500 dan 3000 rpm, panjang pitch 4 mm, 6 mm, 8 mm, 10 mm, serta tinggi rongga 3,415 mm, 3,915 mm dan 5,915 mm. Simulasi menggunakan model turbulensi k-ε RNG. Pada variasi tekanan inlet laju kebocoran paling besar terjadi pada tekanan 15 bar. Pada variasi putaran poros laju kebocoran terjadi berubah secara signifikan pada setiap variasi. Pada variasi tinggi rongga laju kebocoran paling kecil terjadi pada tinggi rongga 3,415 mm. Pada variasi panjang pitch, laju kebocoran paling kecil terjadi pada panjang pitch 10 mm.

  2. Similarity Theory Based Radial Turbine Performance and Loss Mechanism Comparison between R245fa and Air for Heavy-Duty Diesel Engine Organic Rankine Cycles

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    Lei Zhang

    2017-01-01

    Full Text Available Organic Rankine Cycles using radial turbines as expanders are considered as one of the most efficient technologies to convert heavy-duty diesel engine waste heat into useful work. Turbine similarity design based on the existing air turbine profiles is time saving. Due to totally different thermodynamic properties between organic fluids and air, its influence on turbine performance and loss mechanisms need to be analyzed. This paper numerically simulated a radial turbine under similar conditions between R245fa and air, and compared the differences of the turbine performance and loss mechanisms. Larger specific heat ratio of air leads to air turbine operating at higher pressure ratios. As R245fa gas constant is only about one-fifth of air gas constant, reduced rotating speeds of R245fa turbine are only 0.4-fold of those of air turbine, and reduced mass flow rates are about twice of those of air turbine. When using R245fa as working fluid, the nozzle shock wave losses decrease but rotor suction surface separation vortex losses increase, and eventually leads that isentropic efficiencies of R245fa turbine in the commonly used velocity ratio range from 0.5 to 0.9 are 3%–4% lower than those of air turbine.

  3. Thermoeconomic Evaluation of Modular Organic Rankine Cycles for Waste Heat Recovery over a Broad Range of Heat Source Temperatures and Capacities

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    Markus Preißinger

    2017-02-01

    Full Text Available Industrial waste heat recovery by means of an Organic Rankine Cycle (ORC can contribute to the reduction of CO2 emissions from industries. Before market penetration, high efficiency modular concepts have to be developed to achieve appropriate economic value for industrial decision makers. This paper aims to investigate modularly designed ORC systems from a thermoeconomic point of view. The main goal is a recommendation for a suitable chemical class of working fluids, preferable ORC design and a range of heat source temperatures and thermal capacities in which modular ORCs can be economically feasible. For this purpose, a thermoeconomic model has been developed which is based on size and complexity parameters of the ORC components. Special emphasis has been laid on the turbine model. The paper reveals that alkylbenzenes lead to higher exergetic efficiencies compared to alkanes and siloxanes. However, based on the thermoeconomic model, the payback periods of the chemical classes are almost identical. With the ORC design, the developed model and the boundary conditions of this study, hexamethyldisiloxane is a suitable working fluid and leads to a payback period of less than 5 years for a heat source temperature of 400 to 600 °C and a mass flow rate of the gaseous waste heat stream of more than 4 kg/s.

  4. Energy, Exergy and Economic Evaluation Comparison of Small-Scale Single and Dual Pressure Organic Rankine Cycles Integrated with Low-Grade Heat Sources

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    Armando Fontalvo

    2017-09-01

    Full Text Available Low-grade heat sources such as solar thermal, geothermal, exhaust gases and industrial waste heat are suitable alternatives for power generation which can be exploited by means of small-scale Organic Rankine Cycle (ORC. This paper combines thermodynamic optimization and economic analysis to assess the performance of single and dual pressure ORC operating with different organic fluids and targeting small-scale applications. Maximum power output is lower than 45 KW while the temperature of the heat source varies in the range 100–200 °C. The studied working fluids, namely R1234yf, R1234ze(E and R1234ze(Z, are selected based on environmental, safety and thermal performance criteria. Levelized Cost of Electricity (LCOE and Specific Investment Cost (SIC for two operation conditions are presented: maximum power output and maximum thermal efficiency. Results showed that R1234ze(Z achieves the highest net power output (up to 44 kW when net power output is optimized. Regenerative ORC achieves the highest performance when thermal efficiency is optimized (up to 18%. Simple ORC is the most cost-effective among the studied cycle configurations, requiring a selling price of energy of 0.3 USD/kWh to obtain a payback period of 8 years. According to SIC results, the working fluid R1234ze(Z exhibits great potential for simple ORC when compared to conventional R245fa.

  5. Geometry Analysis and Effect of Turbulence Model on the Radial Rotor Turbo-Expander Design for Small Organic Rankine Cycle System

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    Maulana Arifin

    2015-07-01

    Full Text Available Organic Rankine Cycle (ORC is one of the most promising technology for small electric power generations. The geometry analysis and the effect of turbulence model on the radial turbo-expanders design for small ORC power generation systems were discussed in this paper. The rotor blades and performance were calculated using several working fluids such as R134a, R143a, R245fa, n-Pentane, and R123. Subsequently, a numerical study was carried out in the fluid flow area with R134a and R123 as the working fluids. Analyses were performed using Computational Fluid Dynamics (CFD ANSYS Multiphysics on two real gas models, with the k-epsilon and SST (shear stress transport turbulence models. The result shows the distribution of Mach number, pressure, velocity and temperature along the rotor blade of the radial turbo-expanders and estimation of performance at various operating conditions. The operating conditions are as follow: 250,000 grid mesh flow area, real gas model SST at steady state condition, 0.4 kg/s of mass flow rate, 15,000 rpm rotor speed, 5 bar inlet pressure, and 373K inlet temperature. By using those conditions, CFD analysis shows that the turbo-expander able to produce 6.7 kW and 5.5 kW of power when using R134a and R123, respectively.

  6. Thermodynamic Performance Analysis of a Biogas-Fuelled Micro-Gas Turbine with a Bottoming Organic Rankine Cycle for Sewage Sludge and Food Waste Treatment Plants

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    Sunhee Kim

    2017-02-01

    Full Text Available In the Republic of Korea, efficient biogas-fuelled power systems are needed to use the excess biogas that is currently burned due to a lack of suitable power technology. We examined the performance of a biogas-fuelled micro-gas turbine (MGT system and a bottoming organic Rankine cycle (ORC. The MGT provides robust operation with low-grade biogas, and the exhaust can be used for heating the biodigester. Similarly, the bottoming ORC generates additional power output with the exhaust gas. We selected a 1000-kW MGT for four co-digestion plants with 28,000-m3 capacity. A 150-kW ORC system was selected for the MGT exhaust gas. We analysed the effects of the system size, methane concentration, and ORC operating conditions. Based on the system performance, we analysed the annual performance of the MGT with a combined heat and power (CHP system, bottoming ORC, or both a bottoming ORC and CHP system. The annual net power outputs for each system were 7.4, 8.5, and 9.0 MWh per year, respectively.

  7. Thermo-Economic and Heat Transfer Optimization of Working-Fluid Mixtures in a Low-Temperature Organic Rankine Cycle System

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    Oyeniyi A. Oyewunmi

    2016-06-01

    Full Text Available In the present paper, we consider the employment of working-fluid mixtures in organic Rankine cycle (ORC systems with respect to thermodynamic and heat-transfer performance, component sizing and capital costs. The selected working-fluid mixtures promise reduced exergy losses due to their non-isothermal phase-change behaviour, and thus improved cycle efficiencies and power outputs over their respective pure-fluid components. A multi-objective cost-power optimization of a specific low-temperature ORC system (operating with geothermal water at 98 °C reveals that the use of working-fluid-mixtures does indeed show a thermodynamic improvement over the pure-fluids. At the same time, heat transfer and cost analyses, however, suggest that it also requires larger evaporators, condensers and expanders; thus, the resulting ORC systems are also associated with higher costs. In particular, 50% n-pentane + 50% n-hexane and 60% R-245fa + 40% R-227ea mixtures lead to the thermodynamically optimal cycles, whereas pure n-pentane and pure R-245fa have lower plant costs, both estimated as having ∼14% lower costs per unit power output compared to the thermodynamically optimal mixtures. These conclusions highlight the importance of using system cost minimization as a design objective for ORC plants.

  8. Preliminary design of seawater and brackish water reverse osmosis desalination systems driven by low-temperature solar organic Rankine cycles (ORC)

    Energy Technology Data Exchange (ETDEWEB)

    Delgado-Torres, Agustin M. [Dpto. Fisica Fundamental y Experimental, Electronica y Sistemas, Escuela Tecnica Superior de Ingenieria Civil e Industrial, Universidad de La Laguna (ULL), Avda. Astrofisico Francisco Sanchez s/n. 38206 La Laguna (Tenerife) (Spain); Garcia-Rodriguez, Lourdes [Dpto. Ingenieria Energetica, Universidad de Sevilla Escuela Tecnica Superior de Ingenieros, Camino de los Descubrimientos, s/n 41092 Sevilla (Spain)

    2010-12-15

    In this paper, the coupling between the low-temperature solar organic Rankine cycle (ORC) and seawater and brackish water reverse osmosis desalination units has been carried out. Four substances have been considered as working fluids of the solar cycle (butane, isopentane, R245fa and R245ca). With these four fluids the volumetric flow of fresh water produced per unit of aperture area of stationary solar collector has been calculated. The former has been made with the optimized direct vapour generation (DVG) configuration and heat transfer fluid (HTF) configuration of the solar ORC. In the first one (DVG), working fluid of the ORC is directly heated inside the absorber of the solar collector. In the second one (HTF), a fluid different than the working fluid of the ORC (water in this paper) is heated without phase change inside the absorber of the solar collector. Once this fluid has been heated it is carried towards a heat exchanger where it is cooled. Thermal energy delivered in this cooling process is transferred to the working fluid of the ORC. Influence of condensation temperature of the ORC and regeneration's process effectiveness over productivity of the system has also been analysed. Finally, parameters of several preliminary designs of the low-temperature solar thermal driven RO desalination are supplied. R245fa is chosen as working fluid of the ORC in these preliminary designs. The information of the proposed preliminary designs can also be used, i.e., for the assessment of the use of thermal energy rejected by the solar cycle. Overall analysis of the efficiency of the solar thermal driven RO desalination technology is given with the results presented in this paper and the results obtained with the medium temperature solar thermal RO desalination system presented by the authors in previous papers. This work has been carried out within the framework of the OSMOSOL and POWERSOL projects. (author)

  9. Low-Concentration Solar-Power Systems based on Organic Rankine Cycles for Distributed-Scale Applications:Overview and Further Developments

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    Christos N. Markides

    2015-12-01

    Full Text Available This paper is concerned with the emergence and development of low- to medium-grade thermal-energy conversion systems for distributed power generation based on thermodynamic vapour-phase heat-engine cycles undergone by organic working-fluids, namely organic Rankine cycles (ORCs. ORC power systems are, to some extent, a relatively established and mature technology that is well-suited to converting low-/medium-grade heat (at temperatures up to ~ 300 – 400 °C to useful work, at an output power scale from a few kW to 10s of MW. Thermal efficiencies in excess of 25% are achievable at higher temperatures and larger scales, and efforts are currently in progress to improve the overall economic viability, and thus uptake, of ORC power systems by focusing on advanced architectures, working-fluid selection, heat exchangers and expansion machines. Solar-power systems based on ORC technology have a significant potential to be used for distributed power generation, by converting thermal energy from simple and low-cost non-concentrated or low-concentration collectors to mechanical, hydraulic or electrical energy. Current fields of use include mainly geothermal and biomass/biogas, as well as the recovery and conversion of waste heat, leading to improved energy efficiency, primary energy (i.e. fuel use and emission minimization, yet the technology is highly transferable to solar power generation as an affordable alternative to small- to medium-scale photovoltaic (PV systems. Solar-ORC systems offer naturally the advantages of providing a simultaneous thermal-energy output for hot water provision and/or space heating, and the particularly interesting possibility of relatively straightforward on-site (thermal energy storage. Key performance characteristics are presented, and important heat transfer effects that act to limit performance are identified as noteworthy directions of future research for the further development of this technology.

  10. Working Fluid Stability in Large-Scale Organic Rankine Cycle-Units Using Siloxanes—Long-Term Experiences and Fluid Recycling

    Directory of Open Access Journals (Sweden)

    Tobias G. Erhart

    2016-05-01

    Full Text Available The results in this work show the influence of long-term operation on the decomposition of working fluids in eight different organic rankine cycle (ORC power plants (both heat-led and electricity-led in a range of 900 kW el to 2 MW el . All case study plants are using octamethyltrisiloxane (MDM as a working fluid; the facilities are between six to 12 years old. Detailed analyses, including the fluid distribution throughout the cycle, are conducted on one system. All presented fluid samples are analyzed via head space gas chromatography mass spectrometry (HS-GC-MS. Besides the siloxane composition, the influence of contaminants, such as mineral oil-based lubricants (and their components, is examined. In most cases, the original working fluid degrades to fractions of siloxanes with a lower boiling point (low boilers and fractions with a higher boiling point (high boilers. As a consequence of the analyses, a new fluid recycling and management system was designed and tested in one case study plant (Case Study #8. Pre-post comparisons of fluid samples prove the effectiveness of the applied methods. The results show that the recovery of used working fluid offers an alternative to the purchase of fresh fluid, since operating costs can be significantly reduced. For large facilities, the prices for new fluid range from € 15 per liter (in 2006 to € 22 per liter (in 2013, which is a large reinvestment, especially in light of filling volumes of 4000 liters to 7000 liters per unit. Using the aforementioned method, a price of € 8 per liter of recovered MDM can be achieved.

  11. Performance Analysis of an Evaporator for a Diesel Engine–Organic Rankine Cycle (ORC Combined System and Influence of Pressure Drop on the Diesel Engine Operating Characteristics

    Directory of Open Access Journals (Sweden)

    Chen Bei

    2015-06-01

    Full Text Available The main purpose of this research is to analyze the performance of an evaporator for the organic Rankine cycle (ORC system and discuss the influence of the evaporator on the operating characteristics of diesel engine. A simulation model of fin-and-tube evaporator of the ORC system is established by using Fluent software. Then, the flow and heat transfer characteristics of the exhaust at the evaporator shell side are obtained, and then the performance of the fin-and-tube evaporator of the ORC system is analyzed based on the field synergy principle. The field synergy angle (β is the intersection angle between the velocity vector and the temperature gradient. When the absolute values of velocity and temperature gradient are constant and β < 90°, heat transfer enhancement can be achieved with the decrease of the β. When the absolute values of velocity and temperature gradient are constant and β >90°, heat transfer enhancement can be achieved with the increase of the β. Subsequently, the influence of the evaporator of the ORC system on diesel engine performance is studied. A simulation model of the diesel engine is built by using GT–Power software under various operating conditions, and the variation tendency of engine power, torque, and brake specific fuel consumption (BSFC are obtained. The variation tendency of the power output and BSFC of diesel engine–ORC combined system are obtained when the evaporation pressure ranges from 1.0 MPa to 3.5 MPa. Results show that the field synergy effect for the areas among the tube bundles of the evaporator main body and the field synergy effect for the areas among the fins on the windward side are satisfactory. However, the field synergy effect in the areas among the fins on the leeward side is weak. As a result of the pressure drop caused by the evaporator of the ORC system, the diesel engine power and torque decreases slightly, whereas the BSFC increases slightly with the increase of exhaust back

  12. 太阳能有机朗肯循环系统的实验特性%Experimental characteristics of solar organic Rankine cycle system

    Institute of Scientific and Technical Information of China (English)

    宋建忠; 张小松; 李舒宏; 姚启矿; 顾维维

    2014-01-01

    To study the performance of solar organic Rankine cycle (ORC) system, a low temperature solar ORC system is proposed and constructed. The system employs R245fa as the working fluid in the power cycle and WD350 heat transfer oil as the heat transfer fluid in the solar collector. The experimental installation consists of a trough solar collector, a screw expander, a working fluid pump, a heat regenerator, a water cooled condenser, and a vapour generator. When the solar beam radiation is about 400 W·m−2 in the experiment, the thermal oil temperature at the outlet of solar heat collector can reach up to 140℃. The collecting efficiency of the collector is 60% at the outlet oil temperature of 110℃. When the working mode of system changes from basic ORC to regenerative cycle, the calculated efficiency of the system is improved from 9.3% to 10.8%, and the experimental value is improved from 1.57% to 1.67%. The measured exergy efficiency of the system is about 10%. The value under regenerative cycle mode is higher than that under the basic ORC mode. The cycle performance at different working fluid flow rates was also studied. The measured maximum average power output was obtained at 386.27 W and working fluid flow rate of 6.88 kg·min−1. With the increase of working fluid flow rate, both expander inlet pressure and work output increase at fixed heat source temperature. With the increase of heat source temperature, the expander inlet temperature and pressure, and the power output increase at fixed flow rate.%为研究中低温太阳能驱动的有机朗肯循环系统的性能,设计并建造了太阳能驱动的有机朗肯循环实验台。实验中以R245fa为有机朗肯循环工质,以WD350导热油为槽式集热器循环工质,对太阳能有机朗肯循环系统进行了实验研究。实验结果表明,当太阳直射辐射强度在400 W·m−2左右时,集热器出口导热油温度可达140℃。当集热器出口导热油温度在110℃附近

  13. Thermodynamic Analysis of Organic Rankine Cycle System with R1234yf%R1234yf有机朗肯循环系统热力学性能研究

    Institute of Scientific and Technical Information of China (English)

    梁立鹏; 曹园树; 胡冰; 卜宪标; 马伟斌

    2014-01-01

    为提高有机朗肯循环(Organic Rankine Cycle, ORC)在中低温地热収电领域的效率,本文以R1234yf为工质,依据热力学第一定律与第二定律分析了系统单位质量热水净収电功率和系统㶲效率,幵与目前应用广泛的R245fa工质进行了性能对比。研究结果表明,存在最佳蒸収温度和最佳冷凝温度,使得ORC収电系统单位质量热水净収电功率、㶲效率最大。对于热源温度为110℃~150℃的ORC収电系统,R1234yf对应的最大系统单位质量热水净収电功率和最大㶲效率均大于R245fa。%This paper presents a study on optimizing low-medium temperature geothermal Organic Rankine Cycle (ORC) power generation. Here we examine the effect of working fluid R1234yf on net power output per kilogram of geothermal water and exergy efficiency of the system by using first and second thermodynamic laws. The overall system performance is then compared with the system using R245fa. The results show that there exist the optimum evaporation and condensation temperature which can maximize net power output per kilogram geothermal water and exergy efficiency of the system. The maximum net power output per kilogram of geothermal water and exergy efficiency is higher by using R1234yf as working fluid at the geothermal source temperature ranging from 110oC to 150oC.

  14. Optimization of R134a-Organic Rankine Cycle Based on Evolutionary Algorithm%基于进化算法的有机朗肯循环优化设计

    Institute of Scientific and Technical Information of China (English)

    付剑波

    2016-01-01

    The model on the thermodynamic analysis of the Organic Rankine Cycle (ORC) was established. The performance of an ORC system which using the waste gas of a cement kiln as the low-quality heat source, R134a as working lfuid was analyzed. Based on the NSGA-II method, the optimization design of the ORC system was developed, which aim to optimize the net output power of the cycle.%建立有机朗肯循环热力分析模型,对采用R134a为工质,以某水泥窑废气为低品质热源的有机朗肯循环进行了系统性能分析。基于NSGA-II算法,发展了有机郎肯循环性能优化设计方法,以循环净输出功率为目标进行了优化设计。

  15. 云扰动下太阳能驱动有机朗肯循环发电系统的动态特性%Dynamic Performance of Solar Driven Organic Rankine Cycle Power System Under Cloud Disturbance

    Institute of Scientific and Technical Information of China (English)

    赵力; 赵玮奇; 邓帅

    2016-01-01

    Based on the demonstration project of 200,kW focused organic Rankine cycle(ORC)power system driven by solar parabolic trough collector(PTC),a dynamic model was built with Simulink. In terms of the meteorological data of Tianjin City,an analysis was conducted on the dynamic performance of developed solar-ORC system under typical design working conditions and under unconventional working conditions mainly caused by cloud shadow. The results show that power/thermal capacity values of main components have the same variation trend with solar radiation and the average system efficiency is 12.68% under conventional working conditions. Under unconventional working conditions,a linear correlation exists between the variation of heat source temperature and the deteriorative time of system performance,the linear dependence coefficient being about 4.04. In addition,the impact of various heat source temperatures on the power generation of turbine is 1.67 and 2.08 times higher than thermal capacities of evapo-rator and condenser,respectively. The power output of turbine shows a high sensitivity to the variation of heat source temperature.%基于200,kW级聚焦型槽式太阳能集热驱动的有机朗肯循环发电系统示范工程,通过Simulink软件建立了系统的动态模型,采用天津地区的气象数据作为输入,分别分析了典型日系统常规工况和太阳受云遮挡造成直射辐射迅速衰减的非常规工况下系统的动态特性.结果表明:常规工况中系统热、电功率与太阳直射辐射两者变化趋势相同,系统平均效率为 12.68%;非常规工作状况中系统热源温度变化与达到恶劣工况的时间线性相关,相关系数为4.04;汽轮机发电功率受热源温度突变量影响分别是蒸发器和冷凝器的1.67倍和2.08倍,汽轮机输出对热源温度变化呈现高敏感性.

  16. 考虑环境影响的ORC系统综合评价指标及性能分析%Comprehensive evaluation index and performance analysis of organic Rankine cycle system considering environment impact

    Institute of Scientific and Technical Information of China (English)

    张新铭; 余柄宪; 王春

    2014-01-01

    In order to consider thermal economic performance and environmental impact of an organic Rankine cycle(ORC)system, the exergy parameter is used to quantify the environment influence of working fluids and composite performance indicator“comprehensive exergy efficiency integrated environmental influence” is proposed, which combines the environmental effect and cycle thermal economic performance. At thermal source of 150℃, the performance of working fluids of subcritical and transcritical ORC systems is evaluated by the composite performance indicator. Results show that R123 and R32 are suitable for subcritical and transcritical ORC systems respectively when considering the cycle thermal economic performance and refrigerant environmental impact. Although the net power output of transcritical ORC system is higher, the composite performance indicator shows that due to its high circulation evaporation pressure the leakage of working fluids increases. Therefore, subcritical ORC system is a better choice with considering the environmental protection and circulation performance.%为综合评价有机朗肯循环(ORC)系统的热经济和环保性能,采用㶲参数量化工质的环境影响,提出了结合工质环境影响和循环热经济性能的综合评价指标“综合环境影响㶲效率”,在150℃的低温热源条件下,对考虑工质环境影响的亚临界有机朗肯循环和跨临界有机朗肯循环的系统性能进行了分析对比,结果表明,综合考虑循环热经济性能和工质环境影响因素时,R123和 R32分别为亚临界有机朗肯循环系统和跨临界朗肯循环系统的最佳工质;跨临界ORC系统循环净输出功率要高于亚临界ORC系统,但是跨临界ORC系统较高的循环蒸发压力会引起工质泄漏量的增加,进而造成综合环境影响㶲效率并不高,所以综合考虑环保和循环性能时,亚临界ORC系统是较好的选择。

  17. 工质流量对ORC低温余热发电系统性能的影响%Effect of mass flow rate on performance of organic Rankine cycle for power generation system with low-temperature waste heat

    Institute of Scientific and Technical Information of China (English)

    王慧; 马新灵; 孟祥睿; 魏新利

    2015-01-01

    搭建了以自行研发的向心透平为膨胀机的ORC低温余热发电系统实验平台,研究了R123质量流量对循环系统的性能影响。结果表明:液压隔膜泵的温升和熵增均较小,所消耗的功率随流量的增加而增加。工质在蒸发器内的压降明显大于冷凝器内的压降,均随流量的增加而增加;向心透平的等熵效率随质量流量的增加先增加后减小,存在最佳流量0.215 kg·s−1使透平等熵效率达到最大值0.775;系统输出的电功率随流量的增加而增加,流量为0.283 kg·s−1时输出系统最大功率为2.009 kW;蒸发器的㶲损率占系统总㶲损率的比重最大,冷凝器次之,向心透平第三,在本实验最佳质量流量下,三者的㶲损率分别为62%、32%、6%。%An experimental prototype of organic Rankine cycle (ORC) was built for low-temperature waste heat power generation. With R123 as working fluid, heat transfer oil as the waste heat source, and radial inflow turbine as expander, a series of tests were carried out by adjusting the R123 mass flow rate to evaluate the performance of apparatus and system. The temperature rise and entropy increase of hydraulic diaphragm pump were lower, and consumed power increased with the mass flow rate. The pressure drop in the evaporator was greater than that in the condenser, and both increased with the mass flow rate of R123. The isentropic efficiency of the radial inflow turbine increased first and then decreased with the increase of R123 flow rate, with the maximum value of 0.775 kg·s−1 and the optimum value of 0.215 kg·s−1. The system output power increased monotonously to 2.009 kW as the flow rate of R123 increased to 0.283 kg·s−1. Exergy destruction rate of evaporator was the largest parts in total exergy destruction rate, followed by condenser and radial inflow turbine, about 62%, 32% and 6%, respectively, under the optimum condition.

  18. 二次抽汽回热式有机朗肯循环系统热力性能分析%Thermodynamic performance analysis of graded regenerative extraction organic Rankine cycle system

    Institute of Scientific and Technical Information of China (English)

    余廷芳; 李爽

    2016-01-01

    以R365mfc和R245ca作为循环工质,设计了低温余热驱动的二次抽汽回热式有机朗肯循环系统.采用REFPROP 8.0制冷剂物性计算软件及 MATLAB 对该回热系统的热力性能进行计算,并对系统最佳抽汽压力的3种备选方案进行比较.结果表明:以冷凝器出口温度和蒸发器进口温度的3分点温度对应的饱和压力作为抽汽压力(方案3)所对应的系统热效率最高,而采用汽轮机进出口焓值等分点对应压力作为抽汽压力(方案1)所对应的系统单位工质做功能力最大;随着工质蒸汽过热度增大,系统热效率减小,但减小幅度较小,因此,二次抽汽回热式有机朗肯循环系统无需通过增加过热度来提高系统热效率.%Using R245ca and R365mfc as the working fluid,a secondary regenerative extraction organic Ran-kine cycle system driven by low temperature waste heat was designed.The MATLAB software and REF-PROP 8.0 software for refrigerants'physical property(offered by NIST)calculation and were applied to analyze the thermodynamic performance of this regenerative system.Moreover,three candidate schemes for the optimum extraction pressure were compared.The results show that,the system applying scheme III has the highest heat efficiency,in which the saturation pressure corresponding to the trisection temperature of the condenser outlet temperature and the generator inlet temperature is taken as the extraction steam pres-sure.The system applying scheme I has the best ability to work,in which the pressure corresponding to the trisection enthalpy at the steam turbine inlet and outlet is taken as the extraction steam pressure.As the degree of superheat of the steam increases,the heat efficiency and exergy efficiency of the system reduces with low rate.Therefore,the heat efficiency and exergy efficiency of the graded regenerative extraction or-ganic Rankine cycle system can be increased without increasing the degree of superheat of the steam.

  19. Power Generation Systems Using Continuous Blowdown Waste Heat From Drum Boilers Driving an Organic Rankine Cycle%利用汽包锅炉连续排污余热的有机朗肯循环发电系统

    Institute of Scientific and Technical Information of China (English)

    刘强; 段远源; 万绪财

    2013-01-01

    A power generation system which used the continuous blowdown waste heat to drive an organic Rankine cycle (ORC) was developed to improve the energy efficiency. The blowdown waste heat was recovered by organic fluid, and then generates power by expansion through a turbine. The analysis model of thermal performance for the system was established. The performance of seven ORC working fluids including R227ea, RC318, R236ea, R245fa, R245ca, R123 and R113 were optimized using the GRG algorithm, and the maximum power output was obtained. The results show that the optimum turbine inlet temperature increases as the critical temperature of the working fluid decreases for the o2 cycle which has saturated vapor entering the turbine. However, the superheating in the o3 cycle reduces the waste heat utilization ratio. Supercritical ORC improves the match of temperature profiles between the heat source and the working fluid, which helps to increase the system power output. But the high operation pressure and heat transfer deterioration due to the large specific heat near the critical point must be considered in the system design. The thermal performance and the power output of R236ea are better than the six other fluids.%提出了一种利用汽包锅炉排污系统余热的有机朗肯循环发电系统,有机工质回收扩容器疏水的热量,并通过气轮机发电。建立了系统的热力性能分析模型,并对 R227ea、RC318、R236ea、R245fa、R245ca、R123和R113等7种工质的热力性能进行了优化。结果表明,临界温度高的工质,其 o2循环的最佳主气温度(蒸发温度)反而低;亚临界循环采用干流体时,过热不利于余热的利用;超临界循环可以改善热源与工质间的温度匹配,有利于增大系统输出功,但是其运行压力高、大比热区的传热恶化等问题是实际运行和设计需要考虑的因素;R236ea的热力性能优于其余6种工质。

  20. Performance of Organic Rankine Cycle Using Zeotropic Working Fluids for Geothermal Utilization%地热源非共沸工质有机朗肯循环发电性能分析

    Institute of Scientific and Technical Information of China (English)

    郭丛; 杜小泽; 杨立军; 杨勇平

    2014-01-01

    建立有机朗肯循环热力学模型和蒸发器传热模型;基于工质的实验经验状态方程,利用REFPROP 8.0软件获得非共沸工质物性;以获得最佳的凝汽器温度匹配为原则选择工质。采用种温度的地热能,在给定的蒸发器和凝汽器夹点温差下,分析了采用组分比例为0.64:0.36的R600a/R601非共沸工质的有机朗肯循环发电系统的特性,并与R601纯工质发电循环进行了比较。结果表明:以对外输出功为目标函数的利用地热的中低温有机朗肯循环发电系统中不宜加入回热器;对于蒸发器热源进出口温差较小的工况,如热源来自水蒸气凝结放热,采用混合工质的循环的性能不如纯工质的;有机朗肯循环采用混合工质时其最大对外输出功要高于纯工质的,且热源温度越低时,这种优势越明显。%Thermodynamic model of organic Rankine cycle (ORC) and heat transfer model for evaporator were developed, and thermal properties for mixture working fluid were obtained by REFPROP 8.0 on the basis of the empirical equations of state. The selection principle for working fluids was based on the matching between working fluid and cooling water in the condenser. Geothermal energy in three heat source temperatures was simulated, and a zeotropic mixture, R600a/R601 with mole fraction 0.64/0.36, was used as the working fluid of ORC for power generation with the given pinch temperature for the evaporator and condenser. Its performance was analyzed and compared with that of pure working fluid, R601. The analytical results show that it is not suitable to introduce the internal heat exchanger (IHX) to the ORC system using medium or low temperature geothermal energy as heat source with work output as objective function. ORC system with pure working fluid has a better performance than that with mixture under the condition that temperature difference between inlet and outlet of heat source is small (i

  1. Methods of increasing net work output of organic Rankine cycles for low-grade waste heat recovery with a detailed analysis using a zeotropic working fluid mixture and scroll expander

    Science.gov (United States)

    Woodland, Brandon Jay

    An organic Rankine cycle (ORC) is a thermodynamic cycle that is well-suited for waste heat recovery. It is generally employed for waste heat with temperatures in the range of 80 °C -- 300 °C. When the application is strictly to convert waste heat into work, thermal efficiency is not recommended as a key performance metric. In such an application, maximization of the net power output should be the objective rather than maximization of the thermal efficiency. Two alternative cycle configurations that can increase the net power produced from a heat source with a given temperature and flow rate are proposed and analyzed. These cycle configurations are 1) an ORC with two-phase flash expansion and 2) an ORC with a zeotropic working fluid mixture (ZRC). A design-stage ORC model is presented for consistent comparison of multiple ORC configurations. The finite capacity of the heat source and heat sink fluids is a key consideration in this model. Of all working fluids studied for the baseline ORC, R134a and R245fa yield the highest net power output from a given heat source. Results of the design-stage model indicate that the ORC with two-phase flash expansion offers the most improvement over the baseline ORC. However, the level of improvement that could be achieved in practice is highly uncertain due to the requirement of highly efficient two-phase expansion. The ZRC shows improvement over the baseline as long as the condenser fan power requirement is not negligible. At the highest estimated condenser fan power, the ZRC shows the most improvement, while the ORC with flash expansion is no longer beneficial. The ZRC was selected for detailed study because it does not require two-phase expansion. An experimental test rig was used to evaluate baseline ORC performance with R134a and with R245fa. The ZRC was tested on the same rig with a mixture of 62.5% R134a and 37.5% R245fa. The tested expander is a minimally-modified, of-the-shelf automotive scroll compressor. The high

  2. Nant-De-Chatillon: electric power generation by ORC (organic Rankine cycle) using waste heat from the Chatillon biogas plant; Nant-de-Chatillon: Production d'electricite par ORC a partir des rejets de chaleur du site de methanisation de Chatillon. Resume

    Energy Technology Data Exchange (ETDEWEB)

    Kane, M.; Gay, B.

    2005-07-01

    This report prepared for the Swiss Federal Office of Energy (SFOE) describes the practical realisation and testing of a heat recovery system based on a one-stage organic Rankine cycle with R134a as the working fluid. The waste heat has a temperature of 95 {sup o}C and originates from a gas engine that powers a small co-generation plant fuelled with biogas produced on-site. Two similar cycles have been built, ORC1 with one and ORC2 with two turbines. Only ORC1 has been tested so far. The maximum efficiency measured in these tests was 6.64% (theoretical Carnot-efficiency: 17 %) and the electric power output was 5.0 kW. The problems encountered during commissioning are described and recommendations for further improvements are given.

  3. 分级抽汽回热式太阳能低温有机朗肯循环系统的热力性能分析%Thermodynamic Analysis of Graded Regenerative Extraction Low-temperature Power Generation Based on Solar-heated Organic Rankine Cycle

    Institute of Scientific and Technical Information of China (English)

    韩中合; 叶依林; 王璟

    2012-01-01

    The The performances of low-temperature power generation system are investigated based on the graded regenerative extraction Organic Rankine Cycle (ORC) driven by solar. R600 and R245fa are are chosen as the working fluids, thermodynamics analysis and comparison of graded regenerative ORC system and common ORC system are conducted by evaporation temperature and pressure ratio, based on the first law of thermodynamics and the second law of thermodynamics. The conclusion is that the graded regenerative extraction ORC system has higher thermal efficiency,higher second law efficiency,lower irreversible loss and better performance.%研究了分级抽汽回热式太阳能低温有机朗肯循环系统的热力性能.以R600和R245fa作为循环工质,利用热力学第一定律和第二定律,在不同的蒸发温度和膨胀比的条件下,对分级抽汽回热式系统和基本有机朗肯循环系统的热力性能变化进行比较和分析,指出分级抽汽回热式系统的热效率和(炯)效率更高,产生的不可逆损失更小,具有更优越的性能.

  4. Combined System of Organic Rankine Cycle and Brackish Water Desalination for Industrial Gas Flue Waste Heat Recycling Utilization%利用烟气余热的有机朗肯循环与苦咸水淡化联合系统

    Institute of Scientific and Technical Information of China (English)

    刘乙成; 闫广; 高传昌; 王为术

    2013-01-01

    Aimint at the problems of industrial flue gas waste heat emissions and shortage of fresh water in coastal and the northwest areas, a system combined with organic rankine cycle (ORC) and brackish water desalination was designed to reclaim industrial gas flue waste heat and produce fresh water and electricity. The thermal process of the system was dynamic integrated with ORC and flash evaporation. The pentane as working medium was promoted to calculate cycle efficiency of the ORC system with variable parameter method. And then the optimal parameters of the system operation was determined. Compared with water rankine cycle, the advantage of this system was proved.%针对沿海和西北内陆地区淡水紧缺和工业烟气余热的排放问题,设计了一种有机朗肯循环与苦咸水淡化的联合系统对工业烟气余热进行有效回收,以生产淡水和电能.该联合系统将闪蒸法与有机朗肯循环进行有机结合,通过变参数法计算采用戊烷作为工质的有机朗肯循环的循环效率,确定该系统运行的最佳参数,并与水工质朗肯循环进行对比,证明了联合系统的优越性.

  5. Combined Rankin and Organic Rankin Cycles with Screw Expenders

    OpenAIRE

    Tang, Yan

    2014-01-01

    Low pressure saturated steam exists in a lot of industries. The recovery of the energy from the low pressure saturated steam can save tremendous power consumption for those industries. Although the Rankin cycle with a steam turbine can be used to generate the power from the low pressure saturated steam, the isotropic efficiency of the steam turbine is low, the reliability is questionable due to the two phase expansion, and the size is typically large due to the low pressure. This paper presen...

  6. Optimization of Organic Rankine Cycles for Off-Shore Applications

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Larsen, Ulrik; Nguyen, Tuong-Van

    2013-01-01

    In off-shore oil and gas platform efficiency, the reliability and fuel flexibility are the major concerns when selecting the gas turbine to support the electrical and mechanical demand on the platform. In order to fulfill these requirements, turbine inlet temperature and pressure ratio are not in......, cyclohexane at 55.5 bar is the preferable working fluid with a combined thermal efficiency of 44.3%. The supercritical CO2 cycle with a maximum pressure of 192.9 bar is found to be the best alternative if an extremely low hazard is required....... are not increased up to the optimal values and one or more redundant gas turbines may be employed. With increasing incentives for reducing the CO2 emissions off-shore, improving the thermal efficiency has become a focus area. Due to the peculiar low turbine outlet temperature and due to space and weight constraints...... characteristics of the fluids, e.g. stability, environmental and human health impacts, and safety issues. Both supercritical and subcritical ORCs are included in the analysis. The optimization procedure is first applied to a conservative ORC where the maximum pressure is limited to 20 bar. Subsequently...

  7. Selected aspects of operation of supercritical (transcritical organic Rankine cycle

    Directory of Open Access Journals (Sweden)

    Mocarsk Szymon

    2015-06-01

    Full Text Available The paper presents a literature review on the topic of vapour power plants working according to the two-phase thermodynamic cycle with supercritical parameters. The main attention was focused on a review of articles and papers on the vapour power plants working using organic circulation fluids powered with low- and medium-temperature heat sources. Power plants with water-steam cycle supplied with a high-temperature sources have also been shown, however, it has been done mainly to show fundamental differences in the efficiency of the power plant and applications of organic and water-steam cycles. Based on a review of available literature references a comparative analysis of the parameters generated by power plants was conducted, depending on the working fluid used, the type and parameters of the heat source, with particular attention to the needs of power plant internal load.

  8. New concepts for organic Rankine cycle power systems

    NARCIS (Netherlands)

    Casati, E.I.M.

    2014-01-01

    Energy provision is one of the major challenges for the Human Society, and it is increasingly clear that the current production/consumption model is not sustainable. The envisaged energy system is smarter, more decentralised and integrated. Energy conversion systems based on the organic Rankine ther

  9. Emissions-critical charge cooling using an organic rankine cycle

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, Timothy C.; Nelson, Christopher R.

    2014-07-15

    The disclosure provides a system including a Rankine power cycle cooling subsystem providing emissions-critical charge cooling of an input charge flow. The system includes a boiler fluidly coupled to the input charge flow, an energy conversion device fluidly coupled to the boiler, a condenser fluidly coupled to the energy conversion device, a pump fluidly coupled to the condenser and the boiler, an adjuster that adjusts at least one parameter of the Rankine power cycle subsystem to change a temperature of the input charge exiting the boiler, and a sensor adapted to sense a temperature characteristic of the vaporized input charge. The system includes a controller that can determine a target temperature of the input charge sufficient to meet or exceed predetermined target emissions and cause the adjuster to adjust at least one parameter of the Rankine power cycle to achieve the predetermined target emissions.

  10. New concepts for organic Rankine cycle power systems

    NARCIS (Netherlands)

    Casati, E.I.M.

    2014-01-01

    Energy provision is one of the major challenges for the Human Society, and it is increasingly clear that the current production/consumption model is not sustainable. The envisaged energy system is smarter, more decentralised and integrated. Energy conversion systems based on the organic Rankine

  11. Optimization of Organic Rankine Cycles for Off-Shore Applications

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Larsen, Ulrik; Nguyen, Tuong-Van

    2013-01-01

    In off-shore oil and gas platform efficiency, the reliability and fuel flexibility are the major concerns when selecting the gas turbine to support the electrical and mechanical demand on the platform. In order to fulfill these requirements, turbine inlet temperature and pressure ratio are not in......In off-shore oil and gas platform efficiency, the reliability and fuel flexibility are the major concerns when selecting the gas turbine to support the electrical and mechanical demand on the platform. In order to fulfill these requirements, turbine inlet temperature and pressure ratio...... and the thermal efficiency of the cycle can be maximized. This paper is aimed at finding the most optimal ORC tailored for off-shore applications using an optimization procedure based on the genetic algorithm. Numerous working fluids are screened through, considering mainly thermal efficiency, but also other...

  12. Performance Analysis for Waste Heat Recovery System of Vehicle Diesel Engine Based on Organic Rankine Cycle%基于有机朗肯循环的车用柴油机排气余热回收系统性能分析

    Institute of Scientific and Technical Information of China (English)

    杨富斌; 董小瑞; 王震; 杨凯; 张健; 张红光

    2015-01-01

    An organic Rankine cycle (ORC) was designed to recover the exhaust energy from a heavy‐duty vehicle diesel en‐gine and the distribution of diesel engine waste heat under various operating conditions was acquired through the engine bench test .The effects of evaporation pressure ,superheated degree and diesel engine operating condition on the ORC system per‐formances were analyzed and the optimum evaporation pressure of the ORC system was determined by taking the net output power and thermal efficiency as the optimization objectives .The results showed that the maximum net output power of the ORC system was 12 .69 kW and the thermal efficiency was 11 .19% when the evaporation pressure was 1 .8 MPa .It was aslo found that the superheated state of working fluid could not improve the net output power of the ORC system effectively .%利用设计的有机朗肯循环系统回收某重型车用柴油机的排气能量,通过台架试验,获得了变工况下柴油机排气余热能分布特性。分析了有机工质蒸发压力、过热度以及柴油机工况变化对有机朗肯循环系统性能的影响,以系统净输出功率和热效率为优化目标,确定了适用于有机朗肯循环系统的最佳蒸发压力。研究结果表明,当有机工质蒸发压力为1.8 M Pa时,有机朗肯循环系统的净输出功率最大可以达到12.69 kW ,热效率可以达到11.19%;将有机工质加热至过热状态并不能明显提高有机朗肯循环系统的净输出功率。

  13. Performance Analysis of Exhaust Waste Heat Recovery System with Organic Rankine Cycle for Stationary CNG Engine%基于有机朗肯循环的固定式天然气发动机排气余热回收系统性能分析

    Institute of Scientific and Technical Information of China (English)

    娄宗勇; 张红光; 宋松松

    2015-01-01

    An organic Rankine cycle (ORC) system with an internal heat exchanger (IHE) is designed to recover exhaust energy from a stationary compressed natural gas (CNG) engine. According to the ifrst and second laws of thermodynamics, the performances of the ORC system are analyzed. Thereafter, the stationary CNG engine-ORC with IHE combined system is presented. The electric efifciency and the brake speciifc fuel consumption (BSFC) are chosen to evaluate the operating performances of the combined system. The results show that, when the evaporation pressure is 3.5 MPa and the engine is operating at the rated condition, the net power output and the thermal efifciency of ORC system with IHE can reach up to 62.7kW and 12.5%, respectively. Compared with the stationary CNG engine, the electric efifciency of the combined system can be increased by 6.0%, while the BSFC can be reduced by a maximum 5.0%.%针对一台固定式天然气发动机的排气能量变化规律,设计了带回热器的有机朗肯循环排气余热回收系统。基于热力学第一定律和第二定律,对固定式天然气发动机排气余热回收系统性能指标进行了理论计算和分析,进而构建了固定式天然气发动机-带回热器有机朗肯循环联合系统,并采用发电效率和有效燃料消耗率评价联合系统的性能。研究结果表明:当蒸发压力为3.5 MPa,发动机运行在额定工况点时,带回热器有机朗肯循环系统最大净输出功率和热效率分别为62.7 kW和12.5%;与固定式天然气发动机相比,联合系统发电效率最大可提高6.0%,有效燃料消耗率最大可降低5%。

  14. 基于双有机朗肯循环的柴油机余热回收系统性能分析%Performance Analysis of Waste Heat Recovery With a Dual Loop Organic Rankine Cycle System for Diesel Engine

    Institute of Scientific and Technical Information of China (English)

    张红光; 王宏进; 杨凯; 杨富斌; 宋松松; 常莹; 贝晨

    2015-01-01

    To take full advantage of the waste heat from a diesel engine, a set of dual loop organic Rankine cycle ( ORC ) system was designed to recover exhaust energy, waste heat from the coolant system, and released heat from turbocharged air in the intercooler of a six-cylinder diesel engine. Aspen plus software was used to model the dual loop ORC system. According to the simulation model, the operating performance of the dual loop ORC system and the fuel economy of the diesel engine wereinvestigated. The results show that the thermodynamic performance and economy performance of the diesel engine can be effectively improved by using the dual loop ORC system. Under the certain engine operating conditions, namely, engine speedis 2 000 r/min and engine torqueis 1 313 N·m, the total net power output of the dual loop ORC system is up to 43. 65 kW. The brake specific fuel consumption ( BSFC ) and the thermal efficiency of the diesel engine-dual loop ORC combined system are 191. 24 g/( kW·h) and 37. 57%, respectively. Compared with the diesel engine, the thermal efficiency of the combined system can be increased by 13. 69% and the BSFC can be reduced by 15. 86%.%为了有效回收柴油机的尾气、冷却介质和进气中冷的能量,针对一台六缸柴油机,设计了一套双有机朗肯循环系统,结合Aspen plus软件对该系统进行建模,研究双有机朗肯循环系统的运行性能,分析柴油机燃油经济性.经研究发现,加装双有机朗肯循环系统可有效改善原柴油机的热力学性能和经济性能.在设定的柴油机工况下(转速2000 r/mⅰn、转矩1313 N·m),双有机朗肯循环系统的总净输出功率最高可达43.65 kW,柴油机-双有机朗肯循环联合系统的有效燃油消耗率和热效率分别可达191.24 g/( kW·h )和37.57%,相比于原柴油机可分别改善13.69%和15.86%.

  15. 对流热采油页岩过程低温余热ORC系统热力分析%Thermodynamic Analysis of a Low Temperature Waste Heat Organic Rankine Cycle System in the Process of the Convection Heat-based Oil Shale Exploitation

    Institute of Scientific and Technical Information of China (English)

    杨新乐; 赵阳升; 冯增朝; 戴文智

    2012-01-01

    To recover the low temperature waste heat steam produced during the convection heat - based oil shale exploitation, presented and designed was an organic Rankine cycle system for power generation. Under the condition of specific waste heat steam parameters,based on the working medium R245fa for the cycle,a calculation program was prepared to simulate and analyze the law governing the influence of the off - design condition parameters of the ORC system on its thermal efficiency and output power. The numerical simulation results show that when the back pressure of the steam turbine is set at 0.25 MPa,the highest evaporation pressure of the working medium can reach 2. 566 MPa. Within this range of the evaporation pressure, the thermal efficiency of the system will monotonically increase with an increase of the evaporation pressure. Under a same evaporation pressure, it will not increase obviously with an increase of the flow rate of the working medium .however,more net output power can be obtained. When the evaporation pressure is set 1.5 MPa,with a drop of the waste heat discharging temperature,the net output power of the system will increase markedly. With a drop of the back pressure of the steam turbine, the thermal efiGciency of the system will be obviously improved. However, the drop of the back pressure of the steam turbine increases the difficulty for condensing the working medium and the proper back pressure is regarded as 0. 2 MPa.%为回收利用对流热采油页岩过程中产生的低温余热蒸汽,提出并设计有机朗肯循环(ORC)系统进行热力发电.在特定余热蒸汽参数条件下,基于R245fa循环工质,编制计算程序模拟分析了ORC系统变工况参数对该系统热效率及输出功率的影响规律.数值模拟结果表明:设定汽轮机背压为0.25MPa时,工质最高蒸发压力为2.566MPa,在此范围内,系统热效率随蒸发压力升高单调增加,增幅减缓;取蒸发器出口温度85℃时,对于不同的蒸

  16. SMALL TURBOGENERATOR TECHNOLOGY FOR DISTRIBUTED GENERATION

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Sy; Moritz, Bob

    2001-09-01

    This report is produced in under Contract DE-FC26-00NT40914, awarded in accordance with U.S. Department of Energy solicitation DE-PS26-00FT40759, ''Development of Technologies and Capabilities for Fossil Energy-Wide Coal, Natural Gas and Oil R&D Programs'', area of interest 7, ''Advanced Turbines and Engines.'' As a result of ten years of collaborative fuel cell systems studies with U.S. fuel cell manufacturers, initiated to evaluate the gas turbine opportunities likely to result from this technology, Rolls-Royce in Indianapolis has established a clear need for the creation of a turbogenerator to a specification that cannot be met by available units. Many of the required qualities are approached, but not fully met, by microturbines, which tend to be too small and low in pressure ratio. Market evaluation suggests a 1 MW fuel cell hybrid, incorporating a turbogenerator of about 250 kW, is a good market entry product (large enough to spread the costs of a relatively complex plant, but small enough to be acceptable to early adopters). The fuel cell stack occupies the position of a combustor in the turbogenerator, but delivers relatively low turbine entry temperature (1600 F [870 C]). If fitted with a conventional combustor and run stand-alone at full uncooled turbine temperature (1800 F [980 C]), the turbogenerator will develop more power. The power can be further enhanced if the turbogenerator is designed to have flow margin in its fuel cell role (by running faster). This margin can be realized by running at full speed and it is found that power can be increased to the 0.7 to 1.0 MW range, depending on initial fuel cell stack flow demand. The fuel cell hybrid applications require increased pressure ratio (at least 6 rather than the 3-4 of microturbines) and very long life for a small machine. The outcome is a turbogenerator that is very attractive for stand-alone operation and has been the subject of unsolicited enthusiasm from

  17. Problems in the design and development of 750 MW turbogenerators

    CERN Document Server

    Anempodistov, V P; Urusov, I D; Fry, D W; Higinbotham, W

    1963-01-01

    Problems in the Design and Development of 750 MW Turbo-Generators covers selected problems mainly related to projected machines in the development of turbo-generators. This book describes the main lines of research at the Electromechanics Institute of the U.S.S.R. Academy of Sciences.This book is divided into six chapters and begins with an overview of the progress in the generation of electricity along with the rapid economic development of the U.S.S.R. The succeeding chapter deals with the use of efficient cooling system of the winding copper to address the problem of electrical machine's un

  18. Effect of variable heat input on the heat transfer characteristics in an Organic Rankine Cycle system

    Directory of Open Access Journals (Sweden)

    Aboaltabooq Mahdi Hatf Kadhum

    2016-01-01

    Full Text Available This paper analyzes the heat transfer characteristics of an ORC evaporator applied on a diesel engine using measured data from experimental work such as flue gas mass flow rate and flue gas temperature. A mathematical model was developed with regard to the preheater, boiler and the superheater zones of a counter flow evaporator. Each of these zones has been subdivided into a number of cells. The hot source of the ORC cycle was modeled. The study involves the variable heat input's dependence on the ORC system's heat transfer characteristics, with especial emphasis on the evaporator. The results show that the refrigerant's heat transfer coefficient has a higher value for a 100% load from the diesel engine, and decreases with the load decrease. Also, on the exhaust gas side, the heat transfer coefficient decreases with the decrease of the load. The refrigerant's heat transfer coefficient increased normally with the evaporator's tube length in the preheater zone, and then increases rapidly in the boiler zone, followed by a decrease in the superheater zone. The exhaust gases’ heat transfer coefficient increased with the evaporator’ tube length in all zones. The results were compared with result by other authors and were found to be in agreement.

  19. Development of an Organic Rankine Cycle system for exhaust energy recovery in internal combustion engines

    Science.gov (United States)

    Cipollone, Roberto; Bianchi, Giuseppe; Gualtieri, Angelo; Di Battista, Davide; Mauriello, Marco; Fatigati, Fabio

    2015-11-01

    Road transportation is currently one of the most influencing sectors for global energy consumptions and CO2 emissions. Nevertheless, more than one third of the fuel energy supplied to internal combustion engines is still rejected to the environment as thermal waste at the exhaust. Therefore, a greater fuel economy might be achieved recovering the energy from exhaust gases and converting it into useful power on board. In the current research activity, an ORC-based energy recovery system was developed and coupled with a diesel engine. The innovative feature of the recovery power unit relies upon the usage of sliding vane rotary machines as pump and expander. After a preliminary exhaust gas mapping, which allowed to assess the magnitude of the thermal power to be recovered, a thermodynamic analysis was carried out to design the ORC system and the sliding vane machines using R236fa as working fluid. An experimental campaign was eventually performed at different operating regimes according to the ESC procedure and investigated the recovery potential of the power unit at design and off-design conditions. Mechanical power recovered ranged from 0.7 kW up to 1.9 kW, with an overall cycle efficiency from 3.8% up to 4.8% respectively. These results candidate sliding vane machines as efficient and reliable devices for waste heat recovery applications.

  20. Selecting working fluids in an organic Rankine cycle for power generation from low temperature heat sources

    Directory of Open Access Journals (Sweden)

    Fredy Vélez

    2014-01-01

    Full Text Available Este trabajo presenta un estudio termodinámico realizado sobre el uso de fuentes de calor de baja temperatura para la generaci ón de energía a través de un ciclo Rankin e subcrítico con fluidos de trabajo orgánicos. Un análisis d el estado del arte de esta tecn ología muestra como línea de investigación abierta, la selección del fluido de trabajo, pues hasta ahora, no existe un fluido que satisfaga t odos los aspectos medioambientales y técnicos a tener en cuenta en estos ciclos. Por ello, se ha desarrollado una serie de simulaciones que permiten estudiar el comportamiento del ciclo Rankine con difer entes configuraciones y fluidos (húmedo, seco e isoentrópico, permitiendo con ello observar de qué manera influyen cambios ta nto en esos tipos de fluidos utilizados (refrigerantes, hidroca rburos y agua, como de condiciones de temperatura, presión, flujo, etc. , sobre la eficiencia total del ciclo. Con el trabajo realizado se demuestra la viabilidad de este tipo de proceso en la recuperación de calore s en la industria y/o aprovechamiento de fuentes renovables de baja y media temperatura para la producción de energía eléctrica.

  1. A new integrated power plant with a small scale turbine for the organic Rankine cycle

    OpenAIRE

    2012-01-01

    Combined heat and power (CHP or cogeneration) describes the simultaneous generation of electrical power and heat. CHP has been well established for medium and high power ranges (> 100 kW el. power). The Kompakte Dampf Turbine (KDT, meaning compact steam turbine) addresses the low-end of power generation (~2 kW el. power). The KDT is a highly integrated power plant of small dimensions able to use various heat sources. Its simple design promises a low-cost CHP for residential homes.

  2. Using waste energy from the Organic Rankine Cycle cogeneration in the Portland cement industry

    OpenAIRE

    José Pablo Paredes-Sánchez; Oscar Jaime Restrepo-Baena; Beatriz Álvarez-Rodríguez; Adriana Marcela Osorio-Correa; Gloria Restrepo

    2015-01-01

    Este artículo describe una herra mienta de simulación bajo el en torno de Matlab®, que puede ser utilizada para estimar la auton omía de un vehículo con baterías o híbrido con pila de combustible y bater ías. El modelo es función de variables mecánicas y físicas que dependerán no solo del propio vehículo sino también del terreno. Su uso es extendido para recorridos obtenidos mediante dispositivos GPS y para ciclos estándar. Pueden obtenerse diferentes variables de salid a tales como: e...

  3. Multiple regression models for the prediction of the maximum obtainable thermal efficiency of organic Rankine cycles

    DEFF Research Database (Denmark)

    Larsen, Ulrik; Pierobon, Leonardo; Wronski, Jorrit;

    2014-01-01

    to power. In this study we propose four linear regression models to predict the maximum obtainable thermal efficiency for simple and recuperated ORCs. A previously derived methodology is able to determine the maximum thermal efficiency among many combinations of fluids and processes, given the boundary...

  4. Comparative investigation of working fluids for an organic Rankine cycle with geothermal water

    Directory of Open Access Journals (Sweden)

    Liu Yan-Na

    2015-06-01

    Full Text Available In this paper, the thermodynamic investigation on the use of geothermal water (130 °C as maximum for power generation through a basic Rankine has been presented together with obtained main results. Six typical organic working fluids (i.e., R245fa, R141b, R290, R600, R152a, and 134a were studied with modifying the input pressure and temperature to the turbine. The results show that there are no significant changes taking place in the efficiency for these working fluids with overheating the inlet fluid to the turbine, i.e., efficiency is a weak function of temperature. However, with the increasing of pressure ratio in the turbine, the efficiency rises more sharply. The technical viability is shown of implementing this type of process for recovering low temperature heat resource.

  5. Design of organic Rankine cycles using a non-conventional optimization approach

    DEFF Research Database (Denmark)

    Andreasen, J. G.; Larsen, Ulrik; Haglind, F.

    2015-01-01

    90 °C to 285 °C. The results suggest that the conventional optimization approach is not suitable for estimating the performance potential when the temperature profiles in the heat exchangers are closely matched. This is exemplified for the fluid MDM where the temperature profile of preheating aligns...

  6. Uncertainty assessment of equations of state with application to an organic Rankine cycle

    DEFF Research Database (Denmark)

    Frutiger, Jerome; Bell, Ian; O’Connell, John P.

    2017-01-01

    Evaluations of equations of state (EoS) should include uncertainty. This study presents a genericmethod to analyse EoS from a detailed uncertainty analysis of the mathematical form and the dataused to obtain EoS parameter values. The method is illustrated by comparison of Soave–Redlich–Kwong (SRK...

  7. Dynamic Response of a 50 kW Organic Rankine Cycle System in Association with Evaporators

    Directory of Open Access Journals (Sweden)

    Yuh-Ren Lee

    2014-04-01

    Full Text Available The influences of various evaporators on the system responses of a 50 kW ORC system using R-245fa are investigated in this study. First the effect of the supplied hot water flowrate into the evaporator is examined and the exit superheat on the system performance between plate and shell-and-tube evaporator is also reported. Test results show that the effect of hot water flowrate on the evaporator imposes a negligible effect on the transient response of the ORC system. These results prevail even for a 3.5-fold increase of the hot water flowrate and the system shows barely any change subject to this drastic hot water flowrate change. The effect of exit superheat on the ORC system depends on the type of the evaporator. For the plate evaporator, an exit superheat less than 10 °C may cause ORC system instability due to considerable liquid entrainment. To maintain a stable operation, the corresponding Jakob number of the plate heat evaporator must be above 0.07. On the other hand, by employing a shell and tube heat evaporator connected to the ORC system, no unstable oscillation of the ORC system is observed for exit superheats ranging from 0 to 17 °C.

  8. Effect of variable heat input on the heat transfer characteristics in an Organic Rankine Cycle system

    Directory of Open Access Journals (Sweden)

    Aboaltabooq Mahdi Hatf Kadhum

    2016-01-01

    Full Text Available This paper analyzes the heat transfer characteristics of an ORC evaporator applied on a diesel engine using measured data from experimental work such as flue gas mass flow rate and flue gas temperature. A mathematical model was developed with regard to the preheater, boiler and the superheater zones of a counter flow evaporator. Each of these zones has been subdivided into a number of cells. The hot source of the ORC cycle was modeled. The study involves the variable heat input's dependence on the ORC system's heat transfer characteristics, with especial emphasis on the evaporator. The results show that the refrigerant's heat transfer coefficient has a higher value for a 100% load from the diesel engine, and decreases with the load decrease. Also, on the exhaust gas side, the heat transfer coefficient decreases with the decrease of the load. The refrigerant's heat transfer coefficient increased normally with the evaporator's tube length in the preheater zone, and then increases rapidly in the boiler zone, followed by a decrease in the superheater zone. The exhaust gases’ heat transfer coefficient increased with the evaporator’ tube length in all zones. The results were compared with result by other authors and were found to be in agreement.

  9. Thermal-hydraulic issues of flow boiling and condensation in organic Rankine cycle heat exchangers

    Science.gov (United States)

    Mikielewicz, Jarosław; Mikielewicz, Dariusz

    2012-08-01

    In the paper presented are the issues related to the design and operation of micro heat exchangers, where phase changes can occur, applicable to the domestic micro combined heat and power (CHP) unit. Analysed is the stability of the two-phase flow in such unit. A simple hydraulic model presented in the paper enables for the stability analysis of the system and analysis of disturbance propagation caused by a jump change of the flow rate. Equations of the system dynamics as well as properties of the working fluid are strongly non-linear. A proposed model can be applicable in designing the system of flow control in micro heat exchangers operating in the considered CHP unit.

  10. Equation of State Selection for Organic Rankine Cycle Modeling Under Uncertainty

    DEFF Research Database (Denmark)

    Frutiger, Jerome; O'Connell, John; Abildskov, Jens

    combustion, geothermal and solar heat sources. The working fluid is essential to the performance of the cycle. In order to evaluate and test promising fluid candidates, an appropriate Equation of State (EoS) [1] is necessary. For ORC applications, an EoS is commonly selected based on goodness-of-fits to data...

  11. A virtual sensor for monitoring excited thermal turbogenerator rotors

    Directory of Open Access Journals (Sweden)

    Julio R. Gómez Sarduy

    2012-12-01

    Full Text Available The working temperature of an electric generator’s parts is important for its proper operation. The turbogenerator rotor’s temperature is of particular interest regarding its protection and maintenance. Because of the difficulty of measuring the temperature of dynamic parts with real and implicitly robust artificial neural network (ANN sensors it was decided to use a virtual sensor (VS by which average rotor winding temperature is estimated. Because ANN are characterised by learning through training rather than formal descriptions, this has made them the preferred choice for modelling processes involving complex interrelated variables; some are found in the field of instrumentation, as in this research. This paper presents the development of an ANN-based VS applied to an electricity generating company’s 4 MW turbogenerator.

  12. Vibrational diagnostic of turbogenerator stator; Diagnostyka wibracyjna stojana turbogeneratora

    Energy Technology Data Exchange (ETDEWEB)

    Bytnar, A. [Instytut Energetyki, Warsaw (Poland)

    1996-06-01

    The vibrational diagnostic method of technical state assessment of the turbogenerator stator worked-out in the Power Engineering Institute in Warsaw is presented. It enables to detect developing faults, to determine a level of their expansion and a menace for machine operation, to foresee terms of inspections, overhauls and their scope as well as to formulate operational guidelines. A test scope, measuring equipment and some results are also presented. (author). 10 refs., 5 figs.

  13. OPTIMUM CONTROL TO A PARTIALLY CONTROLLED TURBOGENERATOR SHAFT TORSIONAL VIBRATION SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The optimal control to a partially controlled turbogenerator shaft torsional vibration system is investigated. The principle of input feedforward control is presented to achieve the minimum of the average vibration energy in a system,and the optimal control matrix of the system is derived. A turbogenerator shaft system is taken as an example to simulate the optimal control process of the torsional vibration. Results from this simulation indicate that the vibration can be effectively controlled by a partial control strategy.

  14. INVESTIGATION OF SIMULATION EXPERIMENT ON ACTIVE CONTROL OF TORSIONAL VIBRATION IN A TURBOGENERATOR SHAFT SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Hao Zhiyong; Gao Wenzhi

    2004-01-01

    According to the theoretical analysis and calculation on the base of continuous mass system, the simulation experimental investigation on active control of torsional vibration in a turbogenerator shaft system is conducted.A test installation with the excitation of generator motor and multi-stepped shaft system is established to simulate the torsional vibration of a turbogenerator rotor shaft system, and to examine the active control strategy presented.Some useful results are reached in the experimental study.

  15. Identification of Rub and Unbalance in 320-MW Turbogenerators

    Directory of Open Access Journals (Sweden)

    N. Bachschmid

    2004-01-01

    Full Text Available This article presents two experiences of application of a model-based fault identification method on real machines. The first case presented is an unbalance identification on a 320-MW turbogenerator unit operating in a fossil power plant. In the second case, concerning a machine of the same size but of a different manufacturer, the Low Pressure (LP turbine was affected by a rub in the sealings and this time, the fault was modeled by local bows. The identification of the faults is performed by means of a model-based identification technique in frequency domain, suitably modified in order to take into account simultaneous faults. The theoretical background of the applied method is briefly illustrated and some considerations also are presented about the best choice of the rotating speed set of the run-down transient to be used for an effective identification and about the appropriate weighting of vibration measurements at the machine bearings.

  16. Identification of Rub and Unbalance in 320 MW Turbogenerators

    Directory of Open Access Journals (Sweden)

    N. Bachschmid

    2003-01-01

    Full Text Available This article presents two experiences of applying a model-based fault-identification method to real machines. The first case presented is an unbalance identification in a 320 MW turbogenerator unit operating in a fossil power plant. In the second case, concerning a machine of the same size but from a different manufacturer, the turbine has been affected by a rub in the sealings. This time, the fault is modeled by local bows. The identification of the faults is performed by means of a model-based identification technique in a frequency domain, suitably modified in order to take into account simultaneous faults. The theoretical background of the applied method is briefly illustrated and some considerations are also presented about the best choice of the rotating speed set of the run-down transient to be used for an effective identification and about the appropriate weighting of vibration measurements at the machine bearings.

  17. Mathematical modeling of vibrations in turbogenerator sets of Sayano-Shushenskaya Hydroelectric Power Station

    Science.gov (United States)

    Leonov, G. A.; Kuznetsov, N. V.; Solovyeva, E. P.

    2016-02-01

    Oscillations in turbogenerator sets, which consist of a synchronous generator, a hydraulic turbine, and an automatic speed regulator, are investigated. This study was motivated by the emergency that took place at the Sayano-Shushenskaya Hydroelectric Power Station in 2009. During modeling of the parameters of turbogenerator sets of the Sayano-Shushenskaya Hydroelectric Power Station, the ranges corresponding to undesired oscillation regimes were determined. These ranges agree with the results of the full-scale tests of the hydropower units of the Sayano-Shushenskaya Hydroelectric Power Station performed in 1988.

  18. Preliminary Design of Compact Condenser in an Organic Rankine Cycle System for the Low Grade Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    Roberto Capata

    2014-11-01

    Full Text Available The aim of this paper is to present a thermodynamic cycle for the production of electrical power in the 2–5 kW range, suitable for all types of thermally propelled vehicles. The sensible heat recovered from the exhaust gases feeds the energy recovery system, which is able to produce sufficient power to sustain the air conditioning system or other auxiliaries. The working fluids R134a and R245fa have been used in the ORC system, and the systems are simulated by CAMEL-ProTM software. The cycles are generated starting from the same heat source: the exhaust gas of a typical 2.0 L Diesel engine (or from a small size turbine engine. The design of the condenser has been performed to obtain a very compact component, evaluating the heat exchanger tube and fins type design. Through empirical formulas, the area of heat exchange, the heat required to exchange and the pressure drop in the element have been calculated. A commercial software package is used to build the model of the condenser, then a thermal and mechanical analysis and a CFD analysis are realized to estimate the heat exchange. Finally the evaluations, the possible future studies and possible improvements of the system are shown.

  19. Cogenerative Performance of a Wind − Gas Turbine − Organic Rankine Cycle Integrated System for Offshore Applications

    DEFF Research Database (Denmark)

    Bianchi, Michele; Branchini, Lisa; De Pascale, Andrea;

    2016-01-01

    Gas Turbines (GT) are widely used for power generationin offshore oil and gas facilities, due to their high reliability,compactness and dynamic response capabilities. Small heavyduty and aeroderivative units in multiple arrangements aretypically used to offer larger load flexibility, but limitede......Gas Turbines (GT) are widely used for power generationin offshore oil and gas facilities, due to their high reliability,compactness and dynamic response capabilities. Small heavyduty and aeroderivative units in multiple arrangements aretypically used to offer larger load flexibility...

  20. Performance Analysis of a Shell Tube Condenser for a Model Organic Rankine Cycle for Use in Geothermal Power Plant

    OpenAIRE

    2014-01-01

    The global energy demand increases with the economic growth and population rise. Most electrical power is currently generated by conventional methods from fossil fuels. Despite the high energy demand, the conventional energy resources such as fossil fuels have been declining. In addition to this harmful combustion byproducts are resulting global warming. However, the increase of environmental concerns and energy crisis can be minimized by sustainable utilization of the low to ...

  1. Design of a Condenser-Boiler for a Binary Mercury-Organic Rankine Cycle Solar Dynamic Space Power System

    Science.gov (United States)

    1987-05-15

    support the power needs of the space station. Competitive cycles considered have been Brayton, Rankine, and Stirling cycles powered with either nuclear or...at 644 OK, radiator at 350 OK, and pump and turbine efficiencies at 0.54 and 8.72, respectively. There are pressure losses of 10.7% in the regenerator ...10.4% in the "boiler", and 19% drop from turbine outlet to pump (including regenerator and RFMD). These figures represent the preliminary results

  2. Performance Evaluation of HP/ORC (Heat Pump/Organic Rankine Cycle) System with Optimal Control of Sensible Thermal Storage

    DEFF Research Database (Denmark)

    Do Carmo, Carolina Madeira Ramos; Nielsen, Mads Pagh; Elmegaard, Brian

    2016-01-01

    energy in periods of no thermal energy demand and reverses the heat pump cycle to supply electrical power. A dynamic model based on empirical data of this system is used to determine the annual performance. Furthermore, this work assesses the benefits of different control strategies that address...... of the users. Results show that real load control logic can lessen the adverse effects of cycling in the compressor of the system as well as increase the thermal demand (up to 33%) and the electrical demand (max. 8.4%) covered by renewable energy (solar). However, the extension of these improvements is highly......In energy systems with high share of renewable energy sources, like wind and solar power, it is paramount to deal with their intrinsic variability. The interaction between electric and thermal energy (heating and cooling) demands represent a potential area for balancing supply and demand that could...

  3. Optimization of Cycle and Expander Design of an Organic Rankine Cycle Unit using Multi-Component Working Fluids

    DEFF Research Database (Denmark)

    Meroni, Andrea; Andreasen, Jesper Graa; Pierobon, Leonardo;

    2016-01-01

    engine onboard a large ship, and the latter is representative of a low-temperature geothermal, solar or waste heat recovery application. Multi-component working fluids are investigated, as they allow improving the match between the temperature pro-files in the heat exchangers and, consequently, reducing...

  4. Energy Performance and Economic Evaluation of Heat Pump/Organic Rankine Cycle System with Sensible Thermal Storage

    DEFF Research Database (Denmark)

    Carmo, C.; Dumont, O.; Nielsen, M. P.

    2016-01-01

    that consists of a ground-source heat pump with possibility of reversing operation as an ORC power cycle combined with solar heating in a single-family building is introduced. The ORC mode enables the use of solar energy in periods of no heat energy demand and reverses the heat pump cycle to supply electrical......The interaction between electrical and thermal energy demands represent a potential area for balancing supply and demand that could contribute to the integration of intermittent renewables in energy systems. To enable the interaction between thermal and electric energy, an innovative concept...... power.This paper combines a dynamic model based on empirical data of the HP/ORC system with lessons learned from 140 heat pump installations operating in real-life conditions in a cold climate. These installations were monitored for a period up to 5 years.Based on the aforementioned model and real...

  5. Energy performance and economic evaluation of heat pump/organic rankine cycle system with sensible thermal storage

    DEFF Research Database (Denmark)

    Carmo, Carolina; Dumont, Olivier; Nielsen, Mads Pagh

    2016-01-01

    that consists of a ground-source heat pump with possibility of reversing operation as an ORC power cycle combined with solar heating in a single-family building is introduced. The ORC mode enables the use of solar energy in periods of no heat energy demand and reverses the heat pump cycle to supply electrical......The interaction between electrical and thermal energy demands represent a potential area for balancing supply and demand that could contribute to the integration of intermittent renewables in energy systems. To enable the interaction between thermal and electric energy, an innovative concept...... power. This paper combines a dynamic model based on empirical data of the HP/ORC system with lessons learned from 140 heat pump installations operating in real-life conditions in a cold climate. These installations were monitored for a period up to 5 years. Based on the aforementioned model and real...

  6. Design and optimisation of organic Rankine cycles for waste heat recovery in marine applications using the principles of natural selection

    DEFF Research Database (Denmark)

    Larsen, Ulrik; Pierobon, Leonardo; Haglind, Fredrik

    2013-01-01

    , boundary conditions, hazard levels and environmental concerns. A generally applicable methodology, based on the principles of natural selection, is presented and used to determine the optimum working fluid, boiler pressure and Rankine cycle process layout for scenarios related to marine engine heat......Power cycles using alternative working fluids are currently receiving significant attention. Selection of working fluid among many candidates is a key topic and guidelines have been presented. A general problem is that the selection is based on numerous criteria, such as thermodynamic performance...... in cycle efficiency. Furthermore, the results indicated that non-flammable fluids were able to produce near optimum efficiency in recuperated high pressure processes....

  7. Thermodynamic analysis of R134a in an Organic Rankine Cycle for power generation from low temperature sources

    Directory of Open Access Journals (Sweden)

    Fredy Vélez

    2014-01-01

    Full Text Available Este trabajo presenta los principales resultados del estudio termodinámico realizado sobre el uso de una fuente de calor de baja temperatura (150oC como máximo para la generación de energía a través de un ciclo Rankine subcrítico con R134a como fluido de trabajo. El procedimiento para analizar el comportamiento del ciclo propuesto consistió en modificar la presión y temperatura de entrada y/o descarga de la turbina, con el fluido de trabajo en condiciones tanto de saturación, como sobrecalentamiento. Como resultado, se puede indicar que la eficiencia del ciclo con este fluido es una débil función de la temperatura, es decir, sobrecalentar el fluido a la entrada de la turbina no causa un cambio significativo en la eficiencia. Sin embargo, cuando la relación de presión en la turbina aumenta, la eficiencia incrementa, y también, conforme la temperatura de entrada a la turbina aumenta, la eficiencia aumenta pronunciadamente. Además, se analizó el efecto de adicionar un intercambiador interno de calor que aumentó los valores de eficiencia obtenidos, dando como resultado, una eficiencia máxima del 11% y 14% para el ciclo básico y con el intercambiador interno de calor, respectivamente.

  8. Two-circuit cryogenic system for cooling and cryostating a superconductive turbogenerator

    Energy Technology Data Exchange (ETDEWEB)

    Vishnev, I.P.; Kalitin, P.P.; Krauze, A.I.

    1985-01-01

    This paper reports the results of experimentation with a cryogenic system which indicate that the system meets the refrigeration and cryostating requirements of superconductive turbogenerators and the thermal, hydraulic, mechanical and electrical calculation procedures which they have developed and tested and which make it possible to plan similar high-power superconductive electrical devices.

  9. AUTOMATED FORMATION OF CALCULATION MODELS OF TURBOGENERATORS FOR SOFTWARE ENVIRONMENT FEMM

    Directory of Open Access Journals (Sweden)

    V.I. Milykh

    2015-08-01

    Full Text Available Attention is paid to the popular FEMM (Finite Element Method Magnetics program which is effective in the numerical calculations of the magnetic fields of electrical machines. The main problem of its using - high costs in time on the formation of a graphical model representing the design and on the formation of the physical model representing the materials properties and the winding currents of machines – is solved. For this purpose, principles of the automated formation of such models are developed and presented on the turbogenerator example. The task is performed by a program written in an algorithmic language Lua integrated into the package FEMM. The program is universal in terms of varying the geometry and dimensions of the designed turbogenerators. It uses a minimum of input information in a digital form representing the design of the whole turbogenerator and its fragments. A general structure of the Lua script is provided, significant parts of its text, the graphic results of work's phases, as well as explanations of the program and instructions for its use are given. Performance capabilities of the compiled Lua script are shown on the example of the real 340 MW turbogenerator.

  10. 3D-modeling for determination of axial forces acting in elements of the end zone of power turbogenerators

    Directory of Open Access Journals (Sweden)

    Y.A.Haydenko

    2013-12-01

    Full Text Available A field mathematical model of the end zone of a powerful generator type TVV-1000-2U3 in the 3D-setting is developed. Modelling of the nominal mode of turbogenerator operation is done. The distribution of the electromagnetic field, eddy currents, and the Ampere force appearing in such elements of the end zone of turbogenerator as the pressure plate, push pins and electrically conductive screen.

  11. Waste heat recovery technologies for offshore platforms

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Benato, Alberto; Scolari, E.

    2014-01-01

    and of the primary heat exchanger, organic Rankine cycle turbogenerators appear thus to be the preferred solution to abate CO2 emissions and pollutants on oil and gas facilities. As a practical consequence, this paper provides guidelines for the design of high-efficiency, cost-competitive and low-weight power...

  12. Simulating the operation action of an asynchronized turbogenerator under loss of excitation

    Institute of Scientific and Technical Information of China (English)

    SANGARE Adama Fanhiri; YANG Shunchang; LIU Ren

    2004-01-01

    The control strategy tor asynchronized turbogenerators (ASTGs) was studied by using two-axis equations. Simulation of the process of an asynchronized turbogenerator with faults of d or q axis or d and q axes in the excitation system was carried out with the simulating models including the model of the reverse thyristors in the excitation system established by Saber software. The simulation results show that at the loss of excitation at both windings or one winding of the rotor, the ASTGs can be automatically driven into an asynchronous or single axis excitation operation mode without a power unit tripping, and the characteristics for ASTGs with faults in the excitation system appear in good order.

  13. Determination of Permissible Short-Time Emergency Overloading of Turbo-Generators and Synchronous Compensators

    Directory of Open Access Journals (Sweden)

    V. A. Anischenko

    2011-01-01

    Full Text Available The paper shows that failure to take into account variable ratio of short-time emergency overloading of turbo-generators (synchronous compensators that can lead to underestimation of overloading capacity or impermissible insulation over-heating.A method has been developed for determination of permissible duration of short-time emergency over-loading that takes into account changes of over-loading ratio in case of a failure.

  14. AUTOMATED CALCULATIONS OF THE DYNAMICS OF TURBOGENERATOR ELECTROMAGNETIC PROCESSES IN SOFTWARE ENVIRONMENT FEMM

    Directory of Open Access Journals (Sweden)

    V.I. Milykh

    2015-12-01

    Full Text Available Attention is paid to the popular FEMM (Finite Element Method Magnetics program which is effective in the numerical calculations of the magnetic fields of electrical machines. The principles of the automated calculations providing the analysis of the dynamics of electromagnetic processes in turbo-generators are presented. This is realized in the form of a script on the algorithmic language Lua integrated with FEMM. The temporal functions of electromagnetic quantities are obtained by multi-position calculations of the magnetic field with ensuring its rotation together with the turbo-generator rotor. The developed program is universal in terms of the geometry and dimensions of turbo-generators, as well as the modes of their work with a minimum of input data in numerical form. This paper shows "extraction" of discrete temporal functions: the magnetic flux linkage of the phase stator winding; forces acting on the current-carrying and ferromagnetic elements of the structure; the magnetic induction at the fixed points; electromagnetic moment. This list can be expanded as part of the created program, as well as the use of the program can be extended to other types of electrical machines. The obtaining of a change period of any functions is provided by rotating the rotor to 60°.

  15. Zugang zu kindlichen Perspektiven mittels partizipativer Foto-Interviews

    OpenAIRE

    Jorgenson, Jane; Sullivan, Tracy

    2009-01-01

    Mit diesem Artikel wollen wir zur entstehenden Debatte über Kind-zentrierte Forschungsmethoden beitragen, indem wir die Anwendung von partizipativen Foto-Interviews für das Verstehen kindlicher Erfahrungen mit Haushaltgeräten reflektieren. Mittels Foto-Interviews wird versucht, Kinder als aktive Forschungsteilnehmer/innen einzubeziehen, indem ihnen Kameras gegeben und sie eingeladen werden, unterschiedlichste Aspekte ihres Alltagslebens zu fotografieren. Später werden die Fotos im Rahmen ...

  16. Abscheidung funktioneller Schichten mittels Plasmatronzerstäubung

    OpenAIRE

    Kupfer, Hartmut; Ackermann, Eckehard; Hecht, Günther

    2010-01-01

    Zinn- und Zinnlegierungsschichten wurden mittels einer Magnetronquelle auf CuSn6- Substrate aufgebracht. Durch Wahl geeigneter Legierungspartner (Al. Ti), die galvanisch nicht abscheidbar sind, konnten Schichtwerkstoffe mit neuen Eigenschaften hergestellt und hinsichtlich einer Eignung als Kontaktveredelung geprüft werden. Verantwortlich dafür ist eine Umwandlung der grobkristallinen, durch säulenförmige Kristallite geprägten in eine feinkristalline dichte, zur Oberfläche paral...

  17. Behaviour of a turbogenerator with a superconducting field winding considering the third dimension

    Energy Technology Data Exchange (ETDEWEB)

    Bischof, H.

    1987-01-01

    The system equations and system parameters must be known for the mathematical description of the behaviour of a turbogenerator with a superconducting field winding. They are approximately derived from a two dimensional field calculation. Therefore, the generator is described by a shell model. Adapting the impedance loci of the model to those of the real generator, the influence of the third dimension is included. The verification of the resulting machine model is shown by the comparison of simulation results and measurements. Furthermore, it is shown that remarkable reduction of the mechanical stresses on the cylindrical rotor construction during transients is achieved by a free rotatable outer damper cylinder.

  18. The Effect of Flywheel Unbalance on Gear Noise in the Hydraulic Power Plant Turbo-Generator

    Directory of Open Access Journals (Sweden)

    Tomeh Elias

    2017-01-01

    Full Text Available The Effect of Flywheel Unbalance on Gear Noise in the Hydraulic Power Plant Turbo-Generator. Hydraulic power plants are systems that produce electrical energy with high investment costs. In order to fulfil their goals, investments should create conditions for a safe production of energy in a long lasting and reliable way, and with the required power and quality. These goals are possible to reach by an optional control process linked to a systematic monitoring of the operating machinery state, using the method of vibration diagnostics. Lately, there has been an increase of noise level in the hydraulic power plants.

  19. Research on Development of Turbo-generator with Partial Admission Nozzle for Supercritical CO{sub 2} Power Generation

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Junhyun; Shin, Hyung-ki; Lee, Gilbong; Baik, Young-Jin [Korea Institute of Energy Research (KIER), Daejeon (Korea, Republic of); Kang, Young-Seok [Korea Aerospace Research Institute (KARI), Daejeon (Korea, Republic of); Kim, Byunghui [InGineers Ltd., Seoul (Korea, Republic of)

    2017-04-15

    A Sub-kWe small-scale experimental test loop was manufactured to investigate characteristics of the supercritical carbon dioxide power cycle. A high-speed turbo-generator was also designed and manufactured. The designed rotational speed of this turbo-generator was 200,000 rpm. Because of the low expansion ratio through the turbine and low mass flowrate, the rotational speed of the turbo-generator was high. Therefore, it was difficult to select the rotating parts and design the turbine wheel, axial force balance and rotor dynamics in the lab-scale experimental test loop. Using only one channel of the nozzle, the partial admission method was adapted to reduce the rotational speed of the rotor. This was the world’s first approach to the supercritical carbon dioxide turbo-generator. A cold-run test using nitrogen gas under an atmospheric condition was conducted to observe the effect of the partial admission nozzle on the rotor dynamics. The vibration level of the rotor was obtained using a gap sensor, and the results showed that the effect of the partial admission nozzle on the rotor dynamics was allowable.

  20. Life-time of turbogenerators and possibilities of its extension. Turbogeneraattoreiden kaeyttoeikae ja sen pidentaemismahdollisuudet

    Energy Technology Data Exchange (ETDEWEB)

    Lindgren, P.; Bovellan, K.; Koistinen, T.; Eerola, H. (Ekono, Helsinki (Finland))

    1987-04-01

    This report has been prepared on an initiative taken by the Industrial Electric and Automation Committee of The Finnish Energy Economy Association. The average running time of turbogenerators of industrial users in Finland is about 100.000 hours and the age about 15-20 years. Under these circumstances the problems of ageing for different components are becoming evident. As and obvious sign of this is the increased number of generator faults and damages in the last few years. The development of structure of different parts and components as well as the development of manufacturing methods and material used during the part 30 years have been described. A special attention has been paid to those matters which are involved in estimated life-time expectance of turbogenerators. Time of introducing new manufacturing methods and material has been defined. Stresses against different components in view of life-time expectance considering the development of structure and material in different manufacturing periods have been explained. Test and inspection methods for defining the state of condition of different components, for locating possible faults and for specifying the preparing measures to be taken, have been explained. Also the requirements for periodic maintenance of different degrees as well as measures to be taken for life-time extension have been described. Factors during different kind of operation of generators and in different operation conditions, which may cause abnormal stresses to certain components have been examined. Also the guidelines for operation as well as criteria for continuation of operation in faulty conditions have been given. A detailed description on generator protection and their testing has been given.

  1. Conversion of Low Quality Waste Heat to Electric Power with Small-Scale Organic Rankine Cycle (ORC) Engine/Generator Technology

    Science.gov (United States)

    2016-08-01

    system test cases, so zeros out in the Life Cycle Cost Analysis (LCCA) results. 15 The success criterion is that the simple payback period should...site prep , installation/ commissioning. Source: ElectraTherm. Capital Component: FP250, Investment Cost, Residual Value $0 % Straight line

  2. Combined Heat and Power From Low Temperature Heat: HFO-1336mzz(Z) as a Working Fluid for Organic Rankine Cycles

    OpenAIRE

    Kontomaris, Konstantinos; Simoni, Luke D.; Nilsson, Mattias; Hamacher, Tim; Nes Rislå, Harald

    2016-01-01

    Increasing awareness of the environmental impacts associated with the extraction and combustion of fossil fuels and the continued uncertainty of fossil fuel supplies and prices are motivating a renewed interest in the utilization of abundantly available low temperature heat (e.g. waste heat from industrial or commercial processes, mobile or stationary internal combustion engines, geothermal heat, etc.). Conversion of heat to mechanic...

  3. Conversion of Low Quality Waste Heat to Electric Power with Small-Scale Organic Rankine Cycle (ORC) Engine/Generator Technology

    Science.gov (United States)

    2016-06-01

    passed to an ISO 9001 audit conducted by Southern’s Quality system Manager. 6.7.5 Data Management Field data were collected, stored, and retrieved...The system was packaged in two, standard 40 foot ISO containers: the first containing a packaged Cummins 1.2 MW diesel generator, an exhaust gas...operating scenarios. System operability is very good, with low maintenance and minimal training requirements over those for baseline generator set

  4. Integrated modeling of a turbo-generator: analysis, simulation and compensation; Modelado integrado de un turbogenerador: analisis, simulacion y compensacion

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Rodriguez, Isaura Victoria

    2008-09-15

    Currently, most turbogenerator control systems consist of decentralized control schemes with independent control-loops for the turbine and the generator. These schemes do not take into account the interaction between the power and voltage control loops, which can degrade the turbogenerator response. To improve this situation, and to develop better control schemes, it is necessary to build full-scope mathematical models of the turbine generator set, which are able to emulate the dynamics throughout the operating range, including the interaction effects. In this thesis the mathematical model of a synchronous generator, which includes damping windings and rotor iron magnetic saturation, is developed. The model was modularly programmed using per-unit parameters. This model was coupled to the existing model of a gas turbine to compose the full-scope model of a 32 MVA combustion turbogenerator. The numerical stability of the generator and turbogenerator models demonstrated through steady-state simulation experiments. The dynamic behavior was demonstrated using power and voltage control loops based on digital PID algorithms. Then, the results of previous experiments were used to design a control scheme based on two fuzzy compensators: one for power and another for voltage. The proposed fuzzy scheme significantly reduced the unwanted interaction effects of decentralized conventional control schemes. It was demonstrated the proposed turbogenerator model is valid in a wide operating range and allows designing and evaluating high performance control schemes, which take into account the interaction between the turbine and the generator. Besides, the turbogenerator model is being used at the Electrical Research Institute to integrate a real-time bench test for turbogenerator control systems. [Spanish] Actualmente, la mayoria de los sistemas de control para turbogeneradores contemplan esquemas de control descentralizados con lazos de control independientes para la turbina y el

  5. Untersuchung der Auswahl eines schnellen und mittel-kapazitiven öffentlichen Verkehrssystems

    OpenAIRE

    Wang, Tingjing

    2013-01-01

    In der Gegenwart werden BRT und Straßenbahnen immer mehr in chinesischen Städten eingeführt. Die Beiden gehören zu den schnellen und mittel-kapazitiven Nahverkehrssystemen und haben damit viele Gemeinsamkeiten, aber auch Unterschiede. Wenn eine Stadt ein schnelles und mittel-kapazitives Nahverkehrssystem einbauen möchte, müssen die Entscheidungsträger zwischen BRT und Straßenbahn erwägen und auswählen. Mit dieser Frage nimmt diese Arbeit mittelstufige BRT und moderne Straßenbahnen als Unte...

  6. Quantification of multiple fault parameters in flexible turbo-generator systems with incomplete rundown vibration data

    Science.gov (United States)

    Lal, Mohit; Tiwari, Rajiv

    2013-12-01

    A turbo-generator system of the modern rotating machinery consists of the driver and driven shafts, which are coupled through flexible couplings and mounted on flexible bearings. Dynamic characterisation of vital machine elements of such rotating machinery is a challenging problem for reliable and accurate response predictions. In this paper, a key intention is to estimate the bearing and coupling dynamic parameters along with residual unbalances at predefined planes, and the misalignment forces and moments at the coupling based on the rundown vibration data. To tackle a practical difficulty of limited measurements and a numerical difficulty of the conventional dynamic condensation in the development of identification algorithm, a novel condensation technique has been implemented especially to overcome measurement of transverse rotational DOFs. Numerical examples are also presented to show the effectiveness of the proposed method. The measurement noise has been added in numerically simulated responses that are used in the present algorithm to identify the parameters and it is found to be robust. Modelling errors of few physical parameters are also considered and estimates are found to be very good.

  7. Calculating Methods of Inertia Moment of Turbo-Generator Rotor Using Load Rejection Test

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Calculated results of inertia moment of turbo-generator rotor can be quite different by methods used in load rejection tests. In view of fluctuation features of rotor speed rise curve during load rejection tests, the measurement principle of rotor inertia moment was expounded. Based on the measured data in load rejection tests for an imported type of domestic 300-MW generating unit, the rotor speed rise curve was fitted with three kinds of functions to get initial runup rate, but the obtained results differed a lot from each other. According to analysis on the mechanism of rotor speed rise, m=2 consecutive points averaging or FFT (Fast Fourier Transform) smoothing technology was introduced to process test data, and then the initial runup rate was determined by the method of linear fitting of rotor speed in the range of governing valve closing time. Although the obtained curves had a fluctuating shape, the results of rotor inertia moment for 50% and 100% load rejection tests were of good consistency.

  8. Lernen von der eigenen Praxis: Systematische Selbstreflexion mittels Online-Video bei der Lehrerausbildung

    NARCIS (Netherlands)

    Janssen, J.; Hoeks, M.

    2010-01-01

    Anhand einer Fallbeschreibung stellen wir in diesem Aufsatz beispielhaft ein Blended Learning- Ausbildungsmodul vor, das am Institut für Lehrerausbildung der Universität von Amsterdam entwickelt wurde. Im Rahmen dieses Moduls reflektieren Referendare ihr eigenes Lehrerverhalten mittels streaming

  9. 大容量空冷发电机通风及温升研究%Ventilation and Temperature-rise of Large Rate Air-cooled Turbogenerator

    Institute of Scientific and Technical Information of China (English)

    陈楠

    2001-01-01

    本文介绍了济南发电设备厂利用瑞士ABB技术开发的新型空冷汽轮发电机的温升及通风冷却技术特点。%It is introduced that the temperature-rise and ventilation of newair-cooled turbogenerator which designed and manufactured by JPEF with the technology of ABB corporation of switzerland.

  10. Charakterisierung kolorektaler Raumforderungen mittels dynamischer, kontrastmittelunterstützter Magnetresonanz-Kolonographie

    OpenAIRE

    Zorob, Miriam Sylvie

    2009-01-01

    Ziel: Ziel war die Charakterisierung kolorektaler Polypen mittels dynamischer Magnetresonanz-Kolonographie (Dyn-MRC). Material und Methoden: Es wurden 20 Patienten und 14 Kontrollpersonen (40-83 Jahre, Median 60,5) untersucht. Bei allen Patienten wurde nach Darmreinigung die Dyn-MRC in dark lumen Technik an einem 1,5 Tesla MRT durchgeführt. Es wurde zunächst ein nativer 3D Datensatz des Abdomens (coronare T1w GRE-Sequenz) aufgenommen und nach Gabe eines Gadolinium-DTPA-haltigen Kontrastmi...

  11. Vergleichende morphologische Untersuchung der Morgan-Linie mittels Röntgen, Computertomographie (CT) und Magnetresonanztomographie (MRT)

    OpenAIRE

    Stein, Nannette Isabelle

    2016-01-01

    Die hier vorgelegte Studie untersucht 88 Hüftgelenke mit Morgan-Linie von Hunden der HD-Grade A1, A2, B1 und B2 mittels Röntgen, CT und MRT. Die Morgan-Linien werden in 5 verschiedene Morphologie-Gruppen eingeteilt. Es werden verschiedene Parameter im Röntgen (HD-Grad, Subluxationsindex, Norberg-Winkel), in der CT (vorhandenen Arthrosen, Dorsolaterale Subluxation, Dichte des Femurkopf und-hals) und der MRT (Synovial Fluid Index, Kapsel- und Knorpeldicke, Signal des Femurhalses) bestimmt. Ziel...

  12. Technical and Economic Advantages of Turbo-Drive Variant with TRB Turbines over Turbo-Generator Variant in Low Power Engineering

    OpenAIRE

    N. V. Panteley

    2008-01-01

    The paper contains a comparative analysis of turbo-driven variant application with TRB turbines and turbo-generator variant in the low power engineering. High efficiency of steam-turbine drive application with TRB turbines is proved by calculation which is made on the basis of a SE-1250-140 network pump at one of the boilers of the Republic of Belarus taken as an example. Calculation has been made for the following steam parameters: turbo-drive input – 12 kgs/cm and 250 and parameters behind ...

  13. Grundwassermodellbildung – Hydrostratigraphische Bewertungen mittels GCI-PetroKf, Datenbank- und Geoinformationssystemen

    DEFF Research Database (Denmark)

    Koch, Alexander; Fuchs, Sven; Göbel, Patricia

    reimportiert und für die Verwendung in Geoinformationssystemen (i.e. ArcGIS) weiter aufbereitet. Über Interpolationsverfahren konnte innerhalb des Programmes ArcGIS ein lateraler Bezug zwischen den verschiedenen Mächtigkeiten hergestellt werden, um so auf weitere Inhomogenitäten im Aufbau des Grundwasserleiter......-Systems schließen zu können. Anschließend wurden mittels ArcGIS die Quartärbasis des Modellraums konstruiert, sowie Grundwasserisolinien- und Grundwasserdifferenzenkarten berechnet. Die Grundwasserdifferenzenkarten reproduzieren gut die Grundwasserabsenkungen im Bereich von lokalen Tagebauen. Insgesamt zeigen sich...... gute Übereinstimmungen mit früheren hydrogeologischen Untersuchungen im Projektgebiet. Die Kombination des PetroKf-Algorithmus mit der Aufbereitung in einer Datenbank, sowie der Weiterverarbeitung in ArcGIS, zeigt einen praktikablen Weg zur Entwicklung und Parametrisierung eines hydrogeologischen...

  14. DETERMINATION OF ELECTROMAGNETIC PARAMETERS AND PHASE RELATIONS IN TURBO-GENERATORS BY THE AUTOMATED CALCULATION OF THE MAGNETIC FIELD IN THE SOFTWARE ENVIRONMENT FEMM

    Directory of Open Access Journals (Sweden)

    V.I. Milykh

    2016-03-01

    Full Text Available The theoretical bases of calculation of electromagnetic quantities and time-phase relationship are presented for the turbo-generators. This is done by numerical calculations of the magnetic field in the software environment package FEMM (Finite Element Method Magnetics. A program which controls calculations and organizes the issuance of the results to a text file is created on the algorithmic language Lua. The program is universal in terms of a turbo-generator models, as well as steady-state modes of their work with a minimum of input data. The exciting current of the rotor and the phase currents of three-phase stator winding in accordance with their initial phase are given for the calculation of the magnetic field. The key function for the analysis of electromagnetic parameters is the calculated angular function of the magnetic flux phase stator winding. The expansion in the harmonic series is carried out and amplitude and initial phase are received for this function. Next, the phase EMF and voltage, phase shifts between all values, active power, electromagnetic torque, the magnetic flux in the gap and other parameters are determined. The presented Lua script is a prototype for a similar calculation software of electric machines of other types.

  15. Aneurysmatic dissection of an aberrant right subclavian artery; Disseziierendes Aneurysma einer aberranten Arteria subclavia dextra: Diagnose mittels Ultrafast-CT

    Energy Technology Data Exchange (ETDEWEB)

    Reittner, P. [Universitaetsklinik fuer Radiologie, Graz (Austria). Abt. fuer Allgemeine Radiologie; Stacher, R. [Universitaetsklinik fuer Radiologie, Graz (Austria). Abt. fuer Allgemeine Radiologie

    1996-01-01

    Diagnosis with Ultrafast-CT: An aneurysm of an aberrant right subclavian artery is a very rare cause for dysphagia. We describe such a case in a 67-year-old patient, diagnosed with Ultrafast-CT and discuss it together in concert with the embryology and the radiological findings. (orig.) [Deutsch] Eine aberrierende Arteria subclavia dextra ist eine seltene Ursache fuer Dysphagie. Anhand eines 67jaehrigen Patienten werden Embryologie und radiologische Charakteristika, diagnostiziert mittels Ultrafast-CT, diskutiert. (orig.)

  16. Pipe Design Requirements and Pipeline Selection of Power Generation System with Waste Heat Based on Organic Rankine Cycle%基于ORC余热发电系统的管道设计要求和选材

    Institute of Scientific and Technical Information of China (English)

    刘剑剑; 李志; 付保荣

    2012-01-01

    先简要介绍了有机朗肯循环(ORC)的原理及系统组成以及国外已经应用的有机工质的相关特点,然后在常规的管路设计基础上,提出了本系统管道设计基本要求.再结合管道的设计条件,确定适合本系统的管材选用范围.

  17. Performance Study on the Geothermal Bypass Injection-Organic Rankine Cycle Power Generation System%地热热源分流喷射-ORC发电系统性能研究

    Institute of Scientific and Technical Information of China (English)

    彭继慎; 鲁广栋; 宋立业; 李逃昌

    2016-01-01

    为提高中低品位地热发电系统性能,减少发电过程单位功耗㶲损,针对373-423K范围地热水热源,提出一种基于地热热源的分流喷射−ORC 系统以及由喷射器工作条件确定两级换热器蒸发温度的方法,并建立喷射及发电模型。在热力学及能量定律的基础上,编制计算程序分析不同升压比下,两级换热器中蒸发温度对系统性能及喷射器可逆性程度的影响;对不同热源温度下3种系统工况点参数及性能进行分析比较。结果表明:分流喷射/喷射−ORC 系统均具有一最佳升压比a,且其最佳蒸发温度高于ORC系统;随一级蒸发温度升高,系统净输出功降低,而随二级蒸发温度增加,系统热效率增长;在不同热源温度下,分流喷射−ORC系统均具有最高性能,且随热源温度增加,其性能优越性逐渐增强,在Tg=373、423K时,分流喷射−ORC系统可达到净输出功P=280.88、954.82kW,分别高出喷射−ORC及ORC系统12.54、76.31及55.68、141.52kW。通过分流喷射能够提高地热ORC发电性能,热源温度越高,选择分流喷射系统意义愈明显。%In order to improve the performance of low grade geothermal power generation system, and reduce the exergy loss of per unit work, the geothermal bypass injection-ORC system and the method to determine the evaporator temperature range by the injector working conditions were proposed for 373-423K geothermal water heat sources, and the injection and power generation model were established. The influence of two grade heat exchanger evaporator temperature on the performance and injector reversible degree under different boost ratios was analyzed based on the thermodynamic rules and energy principle by wrote the calculation program. The comparison of operating parameter and performance with heat source temperature on three kinds systems were finished. The results show that both two systems with or without bypass have an optimum boost ratio, and which optimal evaporator temperatures are higher than ORC system. The output work decreases with the high grade evaporator temperature, and the thermal efficiency increases with low grade evaporator temperature. The bypass injection-ORC system has the best performance under any heat source temperature, and with the increase of heat source temperature, the superiority is enhanced gradually. The new system can reach 280.88kW, 954.82kW when the heat source temperature is 373 and 423K. It increased by 12.54kW, 76.31kW and 55.68kW, 141.52kW relative to injection-ORC and ORC system respectively. The performance can improve by bypass injection and the higher the heat source temperature is, the significance of choosing the new system is more obvious.

  18. Feasibility Study of Recovery Waste Heat of Flue Gas Using Organic Rankine Cycle%有机朗肯循环回收烟气余热的可行性研究

    Institute of Scientific and Technical Information of China (English)

    马新灵; 王慧; 魏新利; 孟祥睿; 杨凯旋

    2013-01-01

    计算了我国电站锅炉可回收的烟气余热量,并对有机朗肯循环低温余热发电系统进行了热力分析.以2台600 MW燃煤机组的排烟余热为热源、R245fa为工质,确定了余热发电机组的最优运行参数和电力容量.用RETScreen软件对该系统进行了投资收益和节能减排效益分析.结果表明:该余热机组发电量为47 502 MWh/a,电力外销收入为1 900.1万元/a,减排CO2量为42 419 t/a.在初始投资成本6 500元/kW、财务负债比率65%的情况下,投资简单偿还期为2.5年,股本回收仅需1.1年,能源产出比为0.14元/kWh,温室气体减排成本为291元/tCO2.30年运行期内,预计可累积现金4.31亿元.%Flue gas waste heat of utility boiler was calculated.Based on flue gas as heat source and R245fa as working fluid,thermodynamic analysis was carried out to waste heat power generation,and the optimal operation parameters and generating capacity were determined.RETScreen was applied to analyse the investment income and benefit analysis of energy saving and emission reduction.The results show that generating capacity of waste heat unit is 47,502 MWh/a,the emission reductions of CO2 is 42,419 t/a.Under the condition of initial investment costs 6,500 RMB/ kW and debt ratio 65%,equity payback only needs 1.1 years,energy production cost is 0.14 RMB/kWh,GHG reduction cost is 291RMB/tCO2.During operation period of 30 years,the cumulative cash is expected to be 431 million RMB.

  19. Thermodynamic analysis of low-temperature power generation based on solar organic Rankine cycle%基于太阳能的有机朗肯循环低温热发电系统热力性能分析

    Institute of Scientific and Technical Information of China (English)

    韩中合; 叶依林; 王璟; 郑庆宇

    2011-01-01

    The impact of the turbine output temperature and pressure on the system performance of organic Rankine system was investigated. In this paper, nine kinds of organic fluids including R600, R600a, R245fa, R236fa, R236ea, R601, R601a, RC318 and R227ea were taken as cycle working medium. Based on the first and second law of thermodynamics, the thermodynamics analysis revealed the relationship between these two parameters and cycle performances, primarily covering system thermal efficiency, net output power and system irreversibility.%研究了汽轮机进口温度和进口压力对基于太阳能的有机朗肯循环系统性能的影响.以R600,R600a,R245fa,R236fa,R236ea,R601,R601a,RC318,R227ea九种有机工质为例,基于热力学第一定律和第二定律,研究了这两个参数对系统性能变化的影响,主要是对系统热效率、净输出功率以及系统总不可逆损失的影响.

  20. Selection of Working Fluids and Thermodynamic Analysis for Low-temperature Organic Rankine Cycles System%低温有机朗肯循环的工质选择及系统性能分析

    Institute of Scientific and Technical Information of China (English)

    韩中合; 于一达; 王智; 杜燕

    2013-01-01

    Under the proposed working conditions,R123,R141 b,R245ca,R245fa,R601,R601 a are chosen as the working fluids of the low-temperature Rankine cycle system,then those working fluids are investigated and compared based on first law of thermodynamics and second law of thermodynamics.Results show that R141b is an available and effective working fluid for low-temperature Rankine cycle.The impact of the turbine output temperature and pressure on the system performance of organic Rankine system was investigated.Including system net output power,heat absorption capacity and thermal efficiency.%选取R123,R141b,R245ca,R245fa,R601,R601a作为有机朗肯循环的工质,在不同蒸发温度条件下,对其热力循环特性进行了计算分析,以热力学第一定律和第二定律为基础进行了比较.结果表明,R141b是适合本循环系统的最佳工质.同时还研究了汽轮机进口温度和进口压力对该系统的净功量、吸热量及热效率的影响.

  1. A TURBO-GENERATOR DESIGN SYNTHESIS BASED ON THE NUMERICAL-FIELD CALCULATIONS AT VARYING THE NUMBER OF STATOR SLOTS

    Directory of Open Access Journals (Sweden)

    V. I. Milykh

    2016-12-01

    Full Text Available Purpose. The work is dedicated to the presentation of the principle of construction and implementation of an automated synthesis system of the turbo-generator (TG electromagnetic system in the case of its modernization. This is done on the example of changing the number of the stator core slots. Methodology. The basis of the synthesis is a TG basic construction. Its structure includes the mathematical and physical-geometrical models, as well as the calculation model for the FEMM software environment, providing the numerical calculations of the magnetic fields and electromagnetic parameters of TG. The mathematical model links the changing and basic dimensions and parameters of the electromagnetic system, provided that the TG power parameters are ensured. The physical-geometrical model is the geometric mapping of the electromagnetic system with the specified physical properties of its elements. This model converts the TG electromagnetic system in a calculation model for the FEMM program. Results. Testing of the created synthesis system is carried out on the example of the 340 MW TG. The geometric, electromagnetic and power parameters of its basic construction and its new variants at the different numbers of the stator slots are compared. The harmonic analysis of the temporal function of the stator winding EMF is also made for the variants being compared. Originality. The mathematical model, relating the new and base parameters of TG at the changing of the number of the stator slots is created. A Lua script, providing the numerical-field calculations of the TG electromagnetic parameters in the FEMM software environment is worked out. Construction of the constructive and calculation models, the numerical-field calculations and delivery of results are performed by a computer automatically, that ensures high efficiency of the TG design process. Practical value. The considered version of the TG modernization on the example of changing the number of the

  2. 大型汽轮发电机灭磁能容量仿真研究%A De-excitation Capacity Simulation of Large-scale Turbogenerator

    Institute of Scientific and Technical Information of China (English)

    吴龙; 刘为群; 闫伟; 牟伟

    2011-01-01

    The paper presents simulation results of de-excitation of end-short-circuit accident and no-load ceil accident of large-scale turbogenerator. Dynamic differential coefficient equations were created for the 6-rank mathematical model of turbogenerator, de-excitation model of linear or non-linear resistor and the saturation of damping windings and field winding. Finally an example of de-excitation simulation of a 600MW turbogenerator was carried with dynamic simulation program for power system. Simulate results including field voltage, field current, generator stator voltage and generator stator current were presented. The main aim of the paper is to provide evidence for engineering calculator of excitation system according de-excitation capacity comparison between end-short-circuit accident and no-load ceil accident.%本文对大型汽轮发电机空载误强励及机端短路的灭磁行为进行了动态仿真计算,针对非线性或线性电阻灭磁情况,采用发电机六阶数学模型,完全考虑发电机阻尼绕组及磁场饱和,建立发电机空载及短路时动态微分方程组,并利用电力系统动态仿真计算程序,对典型600MW汽轮发电机空载误强励及发电机机端短路灭磁的实例仿真,得出了灭磁过程中磁场电流、电压、发电机电压及电流的变化曲线,计算灭磁时间以及灭磁电阻吸收的磁场能量,最后给出两种灭磁容量的比较结果,为励磁工程设计计算提供依据.

  3. THE NUMERICAL-FIELD ANALYSIS OF THE MAGNETIC FIELD AND THE ELECTRICAL QUANTITIES IN THE TURBOGENERATOR STATOR UNDER AUTONOMOUS UNBALANCED LOADING

    Directory of Open Access Journals (Sweden)

    V. I. Milykh

    2016-11-01

    Full Text Available Purpose. Assessing the impact of load asymmetry of turbogenerator (TG on the magnetic field distribution, on the electrical and energy processes in it based on the numerical-field analysis within the constraints regulated by the standards. Methodology. The calculation model of TG has been constructed on the method of symmetrical components of the three-phase current system. The formed asymmetric system of the currents is used for multi-position numerical calculations of rotating magnetic fields. The temporal functions of the electromagnetic quantities which are subjected to the harmonic analysis are obtained on this basis. Results. Test calculations are conducted on a three-phase 35 MW TG during his work under autonomous unbalanced loading. The analysis of the temporal functions of the magnetic induction at different points of the TG stator and also similar functions of the magnetic flux linkage, EMF phase stator windings and other variables have been executed. Originality. Problems of exploitation of turbo-generators under unbalanced loading are detected by the consideration of their electromagnetic system on the whole, but not their simplified local parts, as usual. It has been shown that the temporal functions of EMF of the phase stator windings under unbalanced loading significantly differ in shape from sine waves and from each other and contain a number of significant upper harmonics. It has been detected that the phase currents would contain not only the first but also significant upper harmonics under unbalanced loading. Practical value. Analysis of the work of TG under unbalanced loading showed the «top» level of problems of electromagnetic character. It has been established that the function of the magnetic induction at the fixed points of the magnetic system on the whole have been changed but not in principle. The temporal functions of EMF, and, hence, the voltage of the stator phase windings significantly differ in shape from sine

  4. Synthese von analogen Filtern auf einer rekonfigurierbaren Hardware-Architektur mittels eines Genetischen Algorithmus

    Directory of Open Access Journals (Sweden)

    S. Trendelenburg

    2008-05-01

    Full Text Available Rekonfigurierbare Analog-Arrays (FPAAs sind der Versuch, die Vorteile der aus der digitalen Welt bekannten FPGAs (Flexibilität, Entwurfsgeschwindigkeit auch für analoge Anwendungen verfügbar zu machen. Aufgrund der Vielfalt der analogen Schaltungstechnik ist die Abbildung von vorgegebenen Schaltungskonzepten auf eine FPAA-Architektur nicht immer einfach lösbar.

    Diese Arbeit stellt einen neuen Ansatz für die Synthese von Filtern auf einer FPAA-Architektur für zeitkontinuierliche Analogfilter mittels eines Genetischen Algorithmus (GA vor. Anhand eines Matlab-Modells des FPAA, das eine gute übereinstimmung mit Simulationen des FPAA auf Transistorebene aufweist, wurde gezeigt, dass eine große Vielzahl verschiedener Filterstrukturen auf dieser Architektur dargestellt werden kann. Daraufhin wurde ein Genetischer Algorithmus entwickelt, der es erlaubt, aus einer gegebenen Filterspezifikation Konfigurationsdatensätze zu synthetisieren, die den gewünschten Filter auf die FPAA-Architektur abbilden.

  5. Permanente sakrale Neuromodulation mittels InterStim®: Ergebnisse einer Anwendungsbefragung zu aktuellen technischen Entwicklungen

    Directory of Open Access Journals (Sweden)

    Sievert KD

    2007-01-01

    Full Text Available In den vergangenen über 20 Jahren wurde die sakrale Neuromodulation als klinische Therapie etabliert. Die anfängliche Indikation wurde ständig erweitert und umfaßt heute verschiedene Formen der Blasen- und Stuhlentleerungsstörung sowie eingeschränkt die Schmerztherapie im kleinen Becken. Fortwährend wurde die Technik der Implantation verbessert und die zur Verfügung stehende Hardware verkleinert. Als Resultat der konsequenten Weiterentwicklung wurde im letzten Jahr der miniaturisierte InterStim® II vorgestellt und dessen klinischer Einsatz durch versierte Operateure der unterschiedlichsten Disziplinen mittels einer internetbasierten Befragung beurteilt. Durch die Verwendung des InterStim® II werden im Vergleich zum InterStim® die operative Invasivität mit der Operationszeit und daraus resultierend der postoperative Schmerz gesenkt. Die neue Fernbedienung läßt einen weiteren Anstieg der Akzeptanz erwarten, da durch das Display der Fernbedienung der Patient die Einstellungen kontrollieren kann. Die weitere Miniaturisierung mit gleichzeitig erweiterter Programmierbarkeit des Implantates, der direkten Verbindung von Elektrode und Impulsgeber mit einer einzelnen Schraube verbessert die Option der Neuromodulation weiter. Die Entwicklungen unterstützen den minimal-invasiven Aspekt der InterStim®-Therapie, wodurch die Möglichkeit der ambulanten Therapieoption gegeben sein könnte. Es bleibt abzuwarten, ob die Therapie der Neuromodulation durch die erweiterten Programmiermöglichkeiten für den einzelnen Patienten in Zukunft noch individueller im chronischen Einsatz optimiert werden kann.

  6. Technical and Economic Advantages of Turbo-Drive Variant with TRB Turbines over Turbo-Generator Variant in Low Power Engineering

    Directory of Open Access Journals (Sweden)

    N. V. Panteley

    2008-01-01

    Full Text Available The paper contains a comparative analysis of turbo-driven variant application with TRB turbines and turbo-generator variant in the low power engineering. High efficiency of steam-turbine drive application with TRB turbines is proved by calculation which is made on the basis of a SE-1250-140 network pump at one of the boilers of the Republic of Belarus taken as an example. Calculation has been made for the following steam parameters: turbo-drive input – 12 kgs/cm and 250 and parameters behind turbo-drive – 1kgs/cm. Comparative analysis has been prepared on the basis of data presented by BelNIPIenergoprom in respect of regional boiler No.3 of Mogilev.

  7. Identifying the influential factors in corrosive processes on the LP shaft of the Elverlingsen E4 turbogenerator set during unit shutdown procedures

    Energy Technology Data Exchange (ETDEWEB)

    Seipp, H.G.; Leidich, F.U. [ALSTOM Power Support GmbH, Mannheim (Germany); Freund, E. [Mark-E AG, Elverlingsen Power Plant (Germany)

    2003-07-01

    Overhauls repeatedly revealed cracks on the grooves of blade suspensions on LP turbine rotors in various turbo-generator sets. Some of these cracks caused costly repairs. Without exception, the starting points of the cracks were identified to be in areas affected by shallow pitting corrosion. In many cases, the same phenomena were found in units which underwent frequent hot and cold start-ups. In order to avoid corrosive attacks on the LP turbine during operational standstills, the shutdown procedures for the unit 4 in Elverlingsen were modified. (orig.) [German] An den Nuten der Schaufelaufhaengungen an ND-Turbinenlaeufern verschiedener Turbogruppen wurden bei Revisionen Risse gefunden, die teilweise aufwaendige Sanierungsmassnahmen zur Folge hatten. Die Rissausgaenge lagen ausnahmslos im Bereich von Muldenkorrosionsangriffen. Besonders haeufig traten diese Phaenomene bei Blockeinheiten mit haeufigen Warm- und Kaltstarts auf. Zur Vermeidung von Korrosionsangriffen an der Niederdruck-Turbine waehrend Betriebsstillstaenden wurde das Abfahren des Blockes 4 im Kraftwerk Elverlingsen modifiziert. (orig.)

  8. 某型微型燃气轮机发电站控制规律研究%Research on Control Method of Micro Turbogenerator

    Institute of Scientific and Technical Information of China (English)

    王军; 蒋茜; 刘明威

    2014-01-01

    微型燃气轮机发电站工作原理复杂,需通过解耦处理,设计分部件多回路控制器,方可实现准确控制。本文将某型微型燃气轮机发电站的控制规律分解为功率环、温度环和转速环,深入研究了转速、排气温度、功率三个核心闭环控制的控制算法。通过仿真计算验证了控制算法的先进性以及控制参数的合理性。因此,功率闭环、温度闭环和转速闭环综合解耦控制的方式适合于微型燃气轮机发电站的应用。%Micro-turbine generator is a kind of power generation equipments.It’s a complex system.According to the composing of Micro turbogenerator,this thesis designs the multilevel controler by decoupling the processing and deeply researches on the control algorithm of speed control loop、the turbine exhaust temperature closed loop and the power closed loop of Micro turbogenerator.At same time, the simulation results has been given out, which confirms that the control algorithm is legitimate and the control parameters is advanced.Therefore, the control algorithm of speed control loop、the turbine exhaust temperature closed loop and the power closed loop is suitable for the application of Micro-turbine generator.

  9. 1000MW超超临界汽轮发电机转子线圈制造技术研究%Rotor Coil Manufacturing Technology for 1O00MW Ultra-supercritical Turbogenerator

    Institute of Scientific and Technical Information of China (English)

    董海涛; 孙朋伟

    2011-01-01

    1000MW turbogenerator is new product of HEC in research and development's domain .As a hard core of the machein, the manufacturing level of rotor coil plays a key role in the generator.This paper briefly describes thc 1000MW ultra-supercritical turbo-generator rotor coil manufacturing process.%1000MW汽轮发电机是哈电机公司研发领域的新产品.线圈作为电机的核心部件,其制造工艺的水平对整个电机运行起着关键作用.本文简要叙述了1000MW超超临界汽轮发电机转子线圈制造的工艺过程.

  10. Parametric sensitivity of two axis models for turbo-generators; Sensibilidad parametrica de modelos de dos ejes para turbogeneradores

    Energy Technology Data Exchange (ETDEWEB)

    Morales Castorena, Armando

    2003-06-15

    The results of parameter sensitivity studies performed on two axis equivalent circuits (TAECs) of synchronous machines are presented in this thesis. The circuits consist of inductive and resistive elements. Their connectivity represents the magnetic and electric coupling inside the machine as well as its energy losses. Two equivalent circuits are needed to represent the machine, one for the direct axis (d) and another for the quadrature axis (q), because it is modeled under the two-axis reaction theory of Park. Parameter values have been identified in advance, using standstill frequency response tests (SSFR). This response was calculated using a finite element model of a turbine generator. The parameter identification is achieved by applying an optimization process based on a hybrid algorithm (stochastic-deterministic). The fitness function is defined as the square of the differences between magnitudes and phase angles of the frequency response functions of the TAECs and of the turbogenerator. This procedure yields the TAECs that better fit the frequency response of the machine. Thus, the circuits identified are considered good models of the machine and they can be applied for digital simulation of dynamic behavior. The identified TAECs are the basis of the parameter sensitivity studies reported here. These studies consist of doing very small variations to parameter values, and to calculate the new value of the fitness function. The ratio between the change of the fitness function to the change in parameter value is called sensitivity of the fitness function, or simply, sensitivity function. Its magnitude indicates which parameter has a greater or lesser influence on the fitness function. If the fitness function is very sensitive to a particular parameter, then the rightness of the identified value of that parameter may be in doubt. With this information it is possible to establish the reliability of the identification process and to exert corrective actions. It is

  11. Failure analysis to the weights of balance of a 350 MW turbo-generator; Analisis de falla a los pesos de balanceo de un turbogenerador de 350 MW

    Energy Technology Data Exchange (ETDEWEB)

    Vital Flores, Francisco; Gamero Arroyo, Jose Manuel [LAPEM, Comision Federal de Electricidad (Mexico)

    2007-11-15

    The selection of materials and the quality control in the supply of the components, as well as the involved operative variables in the process of work to which an equipment, device or a system of a power station of electrical generation are subjected, impact in the same in their useful life in a decisive way. In this document it is presented an analysis of a failure occurred in a 350 MW turbo-generator by the loosening of the balance weights, in which it is mentioned the flaws occurred by this cause and a metallographic analysis that indicates the main fault for the happening. [Spanish] La seleccion de material y el control de calidad en los suministros de los componentes, asi como las variables operativas involucradas en el proceso de trabajo al cual es sometido un equipo, dispositivo o un sistema de una central de generacion electrica, impactan en los mismos de manera decisiva en su vida util. En este documento se presenta un analisis de falla ocurrido en un turbogenerador de 350 MW, por el desprendimiento de los pesos de balanceo, el cual se menciona de los desperfectos ocurridos por esta causa y un analisis metalografico que indica la falla principal por lo ocurrido.

  12. Mittel zum Zweck. Zum Verhältnis von E-Learning und Medienpädagogik

    Directory of Open Access Journals (Sweden)

    Thomas Damberger

    2015-03-01

    Full Text Available Wir leben in einer Mixed Reality, einer Welt, in der Realität und Virtualität bereits ineinander übergegangen sind. In dieser Mixed Reality ist Lernen zu Augmented Learning geworden. Es erscheint als Mittel zum Zweck und der Zweck ist das Menschliche am Menschen. Zugleich ist der Mensch in der Mixed Reality von einer Entfremdung bedroht, der die Medienpädagogik entgegenzuwirken hat. We live in a mixed reality world, where reality and virtuality merged into each other. Learning has turned into augmented learning in this mixed reality. Learning appears as a means to an end and the end is the human in the human being. At the same time humans are threatened by alienation in the mixed reality. Media Education has to work against these tendencies.

  13. An approach of attribute reduction based on FCM and its application in fault diagnosis on turbo-generator unit%FCM属性约简方法在汽轮机故障诊断中的应用

    Institute of Scientific and Technical Information of China (English)

    齐晓轩; 纪建伟; 原忠虎

    2011-01-01

    Fuzzy c-means(FCM) clustering method is applied to discretizing continuous attributes of turbo-generator unit faults by the analysis of spatial distribution of pattern datasets. The attribute reduction algorithm for rough set(RS) is utilized to optimize original feature vectors of turbo-generator unit faults, eliminate redundant information and extract essential information of feature vectors. Fault diagnosis model based on support vector machine(SVM) is built up according to the reduced feature vectors. Experimental results demonstrate that the proposed method can improve the accuracy and real-time performance of fault diagnosis, decrease the number of test items and accordingly cut down the cost of fault diagnosis on turbo-generator unit.%文章通过汽轮机故障样本数据的空间分布状态分析,基于模糊c均值(FCM)聚类方法实现故障征兆参数属性的离散化处理;采用粗糙集(RS)属性约简方法对原始特征向量进行优化,去除冗余特征,提取特征向量的本质信息;基于约简后的特征向量建立支持向量机(SVM)故障诊断模型.实验结果表明,该文所提出的方法不仅可以提高故障诊断的准确性和实时性,还可以减少故障检测项目,降低故障诊断成本.

  14. 1000mw汽轮发电机定子线圈制造技术的研究%Study on the Production Technology of 100OMW Turbo-generator Stator Bar

    Institute of Scientific and Technical Information of China (English)

    刘洪伟; 孔庆斌

    2011-01-01

    Production technology of 1000MW turbo-generator stator bar was described in this paper. We made a lot of innovation and improvement for the manufacturing equipments, tools and the manufacture process. And lots of tests were made too. By the ways above, HEC could produce stator bars of 1000MW turbo-generator with excellent properties.%本文对1000mw汽轮发电机定子线圈制造技术进行了介绍.对线圈的制造设备、工装工具和工艺方面的有所创新与改进,并进行了大量的试验,用多胶模压工艺制造出了1000MW汽轮发电机定子线圈,产品性能优异.为今后哈电机公司批量生产的1 000MW汽轮发电机定子线圈奠定了坚实可靠的基础.

  15. Lightning protection of mobile phone stations in high voltage towers; Blitzschutz bei Mobilfunkstationen auf Mittel- und Hochspannungsmasten. Schutz vor Ueberspannungen

    Energy Technology Data Exchange (ETDEWEB)

    Balzer, G. [TU Darmstadt (Germany); Richter, B. [ABB Hochpannungstechnik, Baden (Switzerland); Schmitt, O. [RWE Net AG, Siegen (Germany)

    2002-12-02

    Transmitter units for mobile phone networks are often installed in existing high voltage towers. In these cases a strict separation of the grounding systems is essential to avoid interferences between the high voltage area and the low voltage energy supply for the mobile phone transmitter station. In order to protect the safety transformer of the mobile phone installation against lightning surges a metall-oxide (MO-) surge arrester is necessary, which furthermore has to withstand the power frequency voltage in case of a single-phase fault in the high voltage power line. For a 110 kV system the power frequency voltage in case of a single-phase short circuit as well as the lightning current stress for a MO-surge arrester is calculated. (orig.) [German] Der weltweit zunehmende Ausbau der Mobilfunknetze erfordert eine grosse Anzahl von Standorten fuer Sende- und Empfangsanlagen. Dabei werden neben neuen Mobilfunkmasten auch Mittel- und Hochspannungsmaste genutzt. Zum Schutz der in den Mobilfunkanlagen eingesetzten Trenntransformatoren gegen moegliche Blitzeinwirkungen werden Metalloxid-Ueberspannungsableiter (MO-Ableiter) eingesetzt. Die Verfasser erlaeutern die geeignete Dimensionierung anhand praktischer Anwendungsbeispiele. (orig.)

  16. Kino filmų titrai kaip kalbų mokymosi priemonė. Untertitel als Mittel zum Fremdsprachenerwerb

    Directory of Open Access Journals (Sweden)

    Alina Baravykaitė

    2007-01-01

    Full Text Available Das in den letzten Jahren spürbare Bestreben der litauischen Gesetzgeber, Untertitelung von Fernsehfilmen zwecks Fremdsprachenerwerb gesetzlich anzuordnen, löste eine Auseinandersetzung in der Öffentlichkeit aus, die sich in der Presse sowie im Internet widerspiegelt und als Anstoß zum vorliegenden Beitrag dient. Diese Arbeit stellt den Versuch dar, die Möglichkeiten und Grenzen der Untertitelung als eines Mittels zum Fremdsprachenerwerb zu untersuchen. Auf Grund der fehlenden wissenschaftlichen Forschungen in diesem Bereich sollen dabei empirische Betrachtungen und die vergleichende Textanalyse von Original und Übersetzung als Hilfe dienen. Auch wenn die Relevanz der Untertitelung für den Fremdsprachenerwerb nicht bestreitbar ist, ist sie aber zugleich nicht zu überschätzen: Durch die lediglich für diese Form der audiovisuellen Übersetzung charakteristischen Merkmale (kurze Einblendezeit, kondensierte Sprache und begrenzte Übertragungsmöglichkeiten von Realia-Begriffen, Phraseologismen, Intertextualismen, dem Wortspiel etc. bleiben dem Zuschauer oft sprachliche Stilmittel vorenthalten und der in allen Übersetzungsbereichen vorkommende unausweichliche Sinn- und Wirkungsverlust des Originals wird erheblich verstärkt. Anbetracht der erwähnten Aspekte und der häufigen fehlerhaften Übersetzungen sollen Untertitel nur als Hilfsmittel beim Fremdsprachenerwerb angewendet werden, wobei herkömmliche Lehr- und Lernstrategien von Fremdsprachen in den Vordergrund treten müssen.

  17. Design and testing of high temperature micro-ORC test stand using Siloxane as working fluid

    Science.gov (United States)

    Turunen-Saaresti, Teemu; Uusitalo, Antti; Honkatukia, Juha

    2017-03-01

    Organic Rankine Cycle is a mature technology for many applications e.g. biomass power plants, waste heat recovery and geothermal power for larger power capacity. Recently more attention is paid on an ORC utilizing high temperature heat with relatively low power. One of the attractive applications of such ORCs would be utilization of waste heat of exhaust gas of combustion engines in stationary and mobile applications. In this paper, a design procedure of the ORC process is described and discussed. The analysis of the major components of the process, namely the evaporator, recuperator, and turbogenerator is done. Also preliminary experimental results of an ORC process utilizing high temperature exhaust gas heat and using siloxane MDM as a working fluid are presented and discussed. The turbine type utilized in the turbogenerator is a radial inflow turbine and the turbogenerator consists of the turbine, the electric motor and the feed pump. Based on the results, it was identified that the studied system is capable to generate electricity from the waste heat of exhaust gases and it is shown that high molecular weight and high critical temperature fluids as the working fluids can be utilized in high-temperature small-scale ORC applications. 5.1 kW of electric power was generated by the turbogenerator.

  18. 大型汽轮发电机环形引线汽堵故障分析%Analysis of steam blockage faults of large turbogenerator circular lead

    Institute of Scientific and Technical Information of China (English)

    赵伟铎; 刘玉新; 杜博超; 崔淑梅

    2014-01-01

    大型汽轮发电机定子环形引线在不当的安装操作下容易引发汽堵故障堵塞水路,造成引线损毁甚至引发停机事故。该文针对具体事故案例,基于计算流体力学方法,建立引线及其冷却水的流固耦合共轭传热仿真模型,计算两起事故外接连通管错误接法下环形引线及其冷却水的温度场,分析温度特征与水路堵塞程度之间的对应关系。计算及分析结果表明,外接连通管错接后冷却水流量过低是导致汽堵故障的直接原因,汽堵发生后约半小时通风不良处的引线开始熔断。在此基础上,提出严格按照说明安装水路水管及加装温度与流量监测装置的预防和改进措施。%Steam blockage faults inside the circular lead of large turbogenerators, which initiated by some installation mistakes, will burn the lead and cause a non-normal shutdown accident. According to specific fault cases, the conjugate heat transfer model of the lead and its cooling water was constructed in this pa-per, based on the computational fluid dynamics. Thermal field of the lead and its water under a wrong re-turn pipe connection was calculated, and then the relationship between temperature characteristics and the degree of blockage was analyzed. The calculation and analysis results indicated that, the abnormal low flow rate caused by a wrong return pipe connection was the direct reason of steam blockage. The lead began to melt about 30 min after the formation of steam blockage. On this basis, this paper suggests a normative installation and extra thermal and flow monitor devices to prevent faults.

  19. ADRE, uso intensivo del ploteo orbital en el diagnóstico de turbogeneradores // ADRE, intensive use of the orbital plot in turbogenerators diagnosis.

    Directory of Open Access Journals (Sweden)

    E. Palomino Marín

    2000-10-01

    themultichanal system ADRE®, employee as system of monitoring off-line. The most excellent results in the investigation, aresustained in the use of the presence of relative movement and seismic transducers under the supervision of theVIBROCONTROL®, through which and with the intervention of the ADRE® system, is possible to identify inadequacies in theon-line monitoring and standing defects are diagnosed in the turbogenerator, including sequels left in this by transitory defects.Key words: seismic transducer, transducer of eddy currents, orbit, phase, keyphasor.

  20. MR imaging of lung ventilation with aerosolized Gadolinium-chelates; MR-Bildgebung der Lungenventilation mittels aerosolierter Gadolinium-Chelate

    Energy Technology Data Exchange (ETDEWEB)

    Haage, P.; Karaagac, S.; Spuentrup, E.; Guenther, R.W. [RWTH Aachen (Germany). Klinik fuer Radiologische Diagnostik; Adam, G. [Universitaetsklinikum Hamburg-Eppendorf (Germany). Abt. fuer Diagnostische und Interventionelle Radiologie

    2003-02-01

    Purpose: To evaluate the feasibility of magnetic resonance assessment of human lung ventilation with aerosolized Gd-chelates in healthy volunteers. Materials and Methods: Five healthy adults (mean age 37 years) were studied with a 1.5 T unit. The volunteers were instructed to inhale the aerosol through an airtight facial mask for 10 minutes. The aerosol was generated with a jet-type small particle nebulizer with attached heater. Ventilation imaging was performed using a respiration-gated dynamic T{sub 1}-weighted turbo spin echo sequence (T{sub R}=199 ms, T{sub E}=8.5 ms, 12 signal averages, slice thickness 10 mm). Pulmonary signal intensity changes were calculated before and after nebulization. Results: The investigation was successfully carried out in all volunteers. An acute or delayed allergic reaction to the aerosolized contrast medium was not observed. In 4 of 5 experiments (80%), a homogeneous signal intensity increase was readily visualized with an average signal increase of 35% after 10 minutes; in one experiment, the aerosol distribution was slightly heterogeneous. (orig.) [German] Ziel: Bestimmung der Durchfuehrbarkeit einer kernspintomographischen Darstellung der Lungenventilation mittels aerosolierter Gd-Chelate bei gesunden Probanden. Methoden: 5 Probanden (Durchschnittsalter 37 Jahre) wurden in einem 1,5T System untersucht. Die Probanden atmeten spontan aerosoliertes Gd-DTPA ueber eine Atemmaske fuer eine Dauer von 10 Minuten. Das Kontrastmittel-Aerosol wurde ueber einen leistungsfaehigen druckluftbetriebenen Vernebler generiert. Die Illustration der Ventilation erfolgte mit einer atemgegateten dynamischen T{sub 1}-gewichteten Turbo-Spin-Echosequenz. Zur Quantitifizerung der Lungenventilation wurden die Signalintensitaeten im Lungengewebe vor und nach Verneblung berechnet. Ergebnisse: Alle Untersuchungen wurden komplikationslos durchgefuehrt und beendet. Eine akute oder verzoegerte Kontrastmittelreaktion wurde nicht beobachtet. In 4 von 5

  1. Coupled Calculation on Stator Fluid Field and Temperature Field of Turbogenerators%汽轮发电机定子流体场和温度场耦合计算与分析

    Institute of Scientific and Technical Information of China (English)

    李俊卿; 许燕萍; 刘彦丰

    2012-01-01

    掌握汽轮发电机中的温度分布对电机冷却系统的优化设计和可靠运行都是非常必要的.在水氢氢冷却的大型汽轮发电机中,存在两种冷却介质和两套冷却系统,其流体流动与传热较复杂.根据其冷却系统内流体流动与传热的特点,建立了定子整个轴向长度范围内流体流动与传热耦合计算的物理模型和数学模型,采用有限体积法对流体场和温度场进行耦合计算,得到了定子本体中详细的温度分布数值及过热点的位置,给出了流体的速度分布图以及定子各部分的温度分布图.详细分析了氢气、冷却水、定子铁心、定子绕组等各部分的温度分布情况.将耦合场计算结果与现场实测数据进行比较,表明了模型和计算方法的正确性.其结论可对水氢氢冷却汽轮发电机的冷却系统设计与实际运行提供理论依据.%It is necessary to know temperature distribution in turbo-generators for optimal design of cooling system and reliable operation of generators. In turbo-generators cooled by water and hydrogen where the fluid-flow and heat-transfer are complicated, there are two cooling mediums and corresponding systems. Considering the characteristics of fluid-flow and heat-transfer of turbo-generators cooled by water and hydrogen, the three-dimensional (3-D) physical and mathematical models of stator overall axis region for fluid and temperature coupling calculation were established, which were calculated numerically by finite volume method, then the temperature distribution and heat spot in stator noumenon were obtained. Fluit velocity and stator temperature contours were provided. The temperature distribution in hydrogen, cooling water, stator iron and windings is analyzed in detail. Theoretical approach together with experimental results confirms the validity of the proposed model and calculation method. The conclusion provides important method and theory basis for design of cooling

  2. 基于虚拟仪器技术的汽轮发电机组扭振测试系统%Virtual instrumentation based measuring system of turbogenerator torsional vibration

    Institute of Scientific and Technical Information of China (English)

    常广; 赵婷; 罗礼全; 王毅; 黄葆华

    2012-01-01

    利用虚拟仪器技术设计和构建了扭振信号采集和分析系统的框架,开发了一种能有效测量和分析扭振的汽轮发电机组扭振测试系统.采用PXI数据采集系统实现了系统的硬件.采用LabVIEW图形化编程语言编制了系统的软件.系统利用汽轮发电机组机端的转速信号.使用零相位数字滤波器直接从转速信号中提取扭振分量.从扭振分量中分离出扭振模态并分析它们的特性.系统已多次应用于电厂的实际调试,实测数据分析显示.该扭振测试系统灵活易用,能满足实际应用的需求.%A framework of data acquisition system is designed via virtual instrumentation technology,based on which a test system is developed to effectively measure and analyze the torsional vibration of turbogenerator. The PXI system is adopted to configure its system hardware and its system software is programmed with LabVIEW language. The speed signal of turbogenerator is recorded and its torsional vibration components are directly extracted by the zero-phase digital filter. Each torsional vibration mode is separated and its corresponding characteristics are analyzed. The analysis of test data from site applications shows that the system is flexible and applicable.

  3. Quantitative fractography under light microscopy: A digital image processing approach; Quantitative Fraktographie mittels Lichtmikroskopie: Naeherung durch digitale Bildverarbeitung

    Energy Technology Data Exchange (ETDEWEB)

    Horovistiz, A.L.; Ribeiro, L.M.F.; Campos, K.A.; Jesuino, G.A.; Guimaraes, V.A.; Hein, L.R.O. [UNESP, Guaratingueta, SP (Brazil)

    2003-02-01

    This work is an example of the improvement on quantitative fractography by means of digital image processing and light microscopy. Two techniques are presented to investigate the quantitative fracture behavior of Ti-4Al-4V heat-treated alloy specimens, under Charpy impact testing. The first technique is the Minkowski method for fractal dimension measurement from surface profiles, revealing the multifractal character of Ti-4Al-4V fracture. It was not observed a clear positive correlation of fractal values against Charpy energies for Ti-4Al-4V alloy specimens, due to their ductility, microstructural heterogeneities and the dynamic loading characteristics at region near the V-notch. The second technique provides an entire elevation map of fracture surface by extracting in-focus regions for each picture from a stack of images acquired at successive focus positions, then computing the surface roughness. Extended-focus reconstruction has been used to explain the behavior along fracture surface. Since these techniques are based on light microscopy, their inherent low cost is very interesting for failure investigations. (orig.) [German] Diese Arbeit ist ein Beispiel fuer die Verbesserung der quantitativen Fraktographie mittels digitaler Bildverarbeitung und Lichtmikroskopie. Zur Untersuchung des quantitativen Bruchverhaltens von waermebehandelten Ti-4Al-4V-Proben im Charpy-Kerbschlagversuch werden zwei Techniken vorgestellt. Die erste Technik ist die Minkowski-Methode zur Messung der fraktalen Dimensionen aus Oberflaechenprofilen, welche den multifraktalen Charakter des Bruches von Ti-4Al-4V ergibt. Es wurde keine eindeutige positive Korrelation zwischen den fraktalen Werten und den Charpyenergien der Ti-4Al-4V-Proben aufgrund deren Duktilitaet, Gefuegeheterogenitaeten und dynamischen Belastungscharakteristiken im Bereich um den V-Kerb beobachtet. Die zweite Methode bietet eine vollstaendige Erhoehungsabbildung der Bruchoberflaeche durch Extraktion der Fokusierungsbereiche

  4. [Bewusstes Erinnern und bewusstes Vergessen : der juristische Umgang mit der Vergangenheit in den Ländern Mittel- und Osteuropas / hrsg. v. Angelika Nußberger, Caroline von Gall. (Jus Internationale et Europaeum ; 52). Mohr Siebeck, Tübingen 2011.

    Index Scriptorium Estoniae

    Luts-Sootak, Marju, 1966-

    2014-01-01

    Arvustus: Bewusstes Erinnern und bewusstes Vergessen : der juristische Umgang mit der Vergangenheit in den Ländern Mittel- und Osteuropas / hrsg. v. Angelika Nußberger, Caroline von Gall (Jus Internationale et Europaeum ; 52). Mohr Siebeck, Tübingen 2011. 400 S.

  5. [Bewusstes Erinnern und bewusstes Vergessen : der juristische Umgang mit der Vergangenheit in den Ländern Mittel- und Osteuropas / hrsg. v. Angelika Nußberger, Caroline von Gall. (Jus Internationale et Europaeum ; 52). Mohr Siebeck, Tübingen 2011.

    Index Scriptorium Estoniae

    Luts-Sootak, Marju, 1966-

    2014-01-01

    Arvustus: Bewusstes Erinnern und bewusstes Vergessen : der juristische Umgang mit der Vergangenheit in den Ländern Mittel- und Osteuropas / hrsg. v. Angelika Nußberger, Caroline von Gall (Jus Internationale et Europaeum ; 52). Mohr Siebeck, Tübingen 2011. 400 S.

  6. Cryotherapy of malignant tumors: MR imaging in comparison with pathological changes in mice; Kryotherapie maligner Tumoren: Untersuchungen mittels MRT im Tierexperiment und Vergleich mit morphologischen Veraenderungen

    Energy Technology Data Exchange (ETDEWEB)

    Romaneehsen, B.; Anders, M.; Roehrl, B.; Hast, H.J.; Schiffer, I.; Neugebauer, B.; Teichmann, E.; Schreiber, W.G.; Thelen, M. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Radiologie; Hengstler, J.G. [Mainz Univ. (Germany). Inst. fuer Toxikologie

    2001-07-01

    Aim of our study was to investigate the efficacy of 7 F cryoprobes for percutaneous use morpho- and histologically, to examine the role of apoptosis after cryotherapy, and to compare contrast-enhanced MRI with histopathological findings at different time intervals in a tumor-mouse model. Methods: Percutaneous cryotherapy was performed in 15 immunocompromised nude mice with subcutaneously implanted tumors using the non-small-cell lung cancer cell line Lu 1. In group a) 7 mice were sacrificed after definite time intervals and histological examinations were done for evaluation of necrosis and apoptosis (HE; TUNEL assay); 2 mice are in long-term follow-up. In group b) in 6 mice tumor destruction and perfusion before and after freezing were investigated with native and contrast-enhanced MR imaging (T{sub 1}- and T{sub 2}-weighted spin-echo) and compared with histopathological findings. Histological control were done in 2 untreated mice. Results: We observed fast tumor-reduction within two weeks (ca. 50%). On long-term follow-up (> 6 months) no recurrence has been noticed so far. Tumors were well vascularized prior to treatment and did not-show contrast enhancement an any time after cryotherapy. A narrow contrast-enhanced zone was seen on the tumor border subcutaneously as a sign of peripheral hyperemia and central vascular stasis after cryotherapy. On histology there was evidence of both apoptosis and necrosis. (orig.) [German] Evaluierung der Durchfuehrbarkeit und Effizienz einer perkutanen Kryotherapie mittels 7-F-Kryosonde in Nacktmaeusen. Erheben des histopathologischen Befundes der Kryolaesion nach definierten Zeitintervallen und Ueberpruefung einer moeglichen Rolle der Apoptose nach Kryotherapie. Darstellung morphologischer Veraenderungen des Tumors und des angrenzenden Gewebes im Anschluss an die Kryotherapie mittels kontrastmittelunterstuetzter MRT. Methodik: Zweiminuetige Kryotherapie subkutan implantierter Tumoren eines nicht-kleinzelligen Bronchialkarzinoms

  7. 基于逆系统方法的汽轮发电机综合控制器%DESIGN OF A TURBO-GENERATOR INTEGRATED CONTROLLER BASED ON THE INVERSE SYSTEM METHOD

    Institute of Scientific and Technical Information of China (English)

    张腾; 戴先中; 陆翔

    2001-01-01

    采用多变量非线性控制的逆系统理论分析了汽轮发电机组励磁与汽门系统的可逆性,并运用逆系统方法将这一多变量、非线性、强耦合的复杂被控对象解耦成两个独立的SISO线性化积分型子系统,然后基于线性系统理论设计了综合控制器。研究结果表明,该控制策略实现了励磁控制与汽门调节的动态解耦,应用该方法可显著提高电力系统的暂态稳定性。%Based on the multivariable inverse system theory, this paperanalyses the invertibility of the excitation and valve system for turbo-generators. With decoupling the multivariable nonlinear system of excitation and valve control into two SISO linear integral subsystems, one can easily design two linear controllers for each subsystem based on linear system theory. The simulation result shows that the control strategy can realize the dynamic decoupling control of excitation and valve and so it can considerably increase the dynamic stability of power system.

  8. 22kV级汽轮发电机定子整机介质损耗测试研究%Study on Measurement of Dielectric Loss of Stator Winding of Turbo-generator for 22kV

    Institute of Scientific and Technical Information of China (English)

    任东滨; 胡波; 张小俊; 刘伟

    2013-01-01

      本文介绍了发电机定子整机介质损耗的测试原理、测试方法及影响因素,收集整理了近几年额定电压为22kV的汽轮发电机定子整机介质损耗测试数据,分析了测试数据的分布范围和分布特点,提出了在测试过程中应注意的相关事项,为制订产品相关标准打下了基础。%The measuring theory, measuring method and effective factor of dielectric loss of stator winding of generator are introduced. The measuring data of dielectric loss of stator winding of turbo-generator for rated voltage of 22kV is collected. The distribution arrange and characteristics are analyzed. The attention items are proposed during measurement. It can be referred for the establishment of industrial standards.

  9. Recovery of industrial low-grade waste heat by means of organic rankine cycle(ORC) method with low boiling point working fluid%用低沸点工质的朗肯循环(ORC)方法回收低位工业余热

    Institute of Scientific and Technical Information of China (English)

    张红

    2004-01-01

    我国的中低温余热发电技术尚不很成熟.本文介绍以低沸点的有机物(正戊烷N-pantane)作为工质来回收废气余热、汽化进入汽轮机膨胀作功,带动发电机发电的有机朗肯循环(ORC)余热发电技术,对于低位工业余热及地热能的开发,都有重要的参考价值.

  10. 大型汽轮发电机定子绕组端部电动力三维有限元计算%The 3D FEM Calculation of Electromagnetic Force on the End Stator Windings of Large Turbo-generator

    Institute of Scientific and Technical Information of China (English)

    胡刚; 张建涛; 李金香

    2013-01-01

    This paper presented a method for calculating the force on the end stator windings by taking a 660MW turbo-generator for an example. Firstly, the FEM mathematic model for calculating 3D end field of large turbo-generator is presented. And a solid model of the end of stator windings of the turbo-generator is built according to the actual shape. Through numerical calculating the distribution of end field at the moment of the maximum short current achieved is gained. Basing on the calculating the force on the end of stator windings and the distribution of the force on the each bar are obtained. The effect of the exciting current on the magnetic force is compared and discussed, which provides some references for the design of the stator end support structures.%  本文以一台660MW汽轮发电机为例,详细阐述了汽轮发电机定子端部电动力的计算方法。首先提出了大型汽轮发电机三维端部磁场的有限元数学模型,并按真实形状建立了汽轮发电机定子绕组端部实体模型。计算得到了三相突然短路时出现电流最大时刻的端部磁场分布,在此基础上得到每根定子线棒所受到的端部电动力及单根线棒的电动力分布规律。讨论比较了励磁电流对定子线棒端部电动力的影响,为发电机端部结构设计提供依据。

  11. 汽轮发电机组轴系对中自动检测系统的研究%A Study on Automatic Measurement System for Aligning the Shafts of a Turbo-Generator Set

    Institute of Scientific and Technical Information of China (English)

    芮晓明; 李林; 刘衍平; 何缨

    2001-01-01

    对汽轮发电机组安装、检修过程中的轴系对中及调整方法进行了研究。设计了轴系参数自动检测技术方案,建立了轴系对中调整的模型及优化算法,并在此基础上,开发研制出由功能可靠的硬件和适合检修现场工况的智能软件组成的汽轮机轴系对中自动检测系统。该系统已在电力企业得到成功应用。与以往工艺比较,因其测量精度高并能提供优化的调整方案,可有效保证调整质量, 明显减少测量和调整的次数,提高效率。%A method for aligning the shafts of a turbo-generator set is introduced.A technical scheme for automatically measuring the shafts parameters is designed.A modol for the alignment of shafts and its optimal algorithm are presented.An automatic measurement system which is composed of excellent hardwares and intelligent softwares suitabe for its application in the maintenance spot is developed.The system has been successfully in the power plant.Comparing with a traditional maintenance technology,the new system has a higher accuracy and an adjustable optimal scheme,can effectively guarantee the alignment precision,and raise the measurement efficiency.

  12. Measurement of the filling height of transient two-phase surge flows in pipelines by means of electronics; Messung der Fuellhoehe von transienten Zweiphasenschwallstroemungen in Rohrleitungen mittels Ultraschall

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, B.; Rockstroh, M. [Technische Univ. Dresden (Germany). Inst. fuer Energiemaschinen und Maschinenlabor

    1997-12-01

    The aim of the ultrasonic measurements was the determination of the time course of the level of a transient surge flow with swirl and waves in partly filled roughly horizontally laid pipelines. The running time of the ultrasonic waves from the test head to the liquid surface and back was measured for this purpose. The course of the stress was recorded digitally and was evaluated with the aid of software. Waves, swirl, turbulence of flow and introduced test bodies in the flow caused typical echoes, which had to be taken into account in the evaluation. As the test head was fitted on the outside of the pipe (clamp-on technique), the pipe wall thickness and the speed of sound in the pipe wall had to be included in the calculation of filling height by means of a correction. [Deutsch] Ziel der Ultraschallmessungen war die Bestimmung des zeitlichen Verlaufes der Fuellhoehe einer transienten, drall- und wellenbehafteten Schwallstroemung in teilgefuellten, etwa horizontal verlegten Rohrleitungen. Hierzu wurde die Laufzeit der Ultraschallwellen vom Pruefkopf zur Fluessigkeitsoberflaeche und zurueck gemessen. Die Laufzeit der Ultraschallwellen wurde auf eine quasi-analog elektrische Spannung abgebildet. Der Spannungsverlauf wurde digital aufgezeichnet und softwaregestuetzt ausgewertet. Wellen, Drall, Stroemungsturbulenzen sowie eingebrachte Pruefkoerper in der Stroemung hatten typische Echoerscheinungen zur Folge, die bei der Auswertung zu beruecksichtigen waren. Da der Pruefkopf aussen am Rohr angebracht war (clamp-on-Technik), musste die Rohrwandstaerke und die Schallgeschwindigkeit in der Rohrwandung mittels eines Korrekturgliedes in die Fuellhoehenberechnung eingezogen werden. (orig.)

  13. Modernisation of power plants in central and eastern Europe: High demand for creativity; Modernisierung von Kraftwerken in Mittel- und Osteuropa: Viel Kreativitaet gefragt

    Energy Technology Data Exchange (ETDEWEB)

    Schwegmann, P.

    1998-07-01

    The retrofitting of old power plants in central and eastern Europe is a task of enormous dimensions and great importance. As all governments there are low in funds, measures to extend service life of the plants are an essential economic alternative to erecting new plants. The demand for retrofitting work opens up good marketing chances for power plant manufacturers of the West on the basis of cooperation agreements with domestic plant manufacturers in those countries, as is shown by the activities of Siemens/KWU. Now as before, creativity is much in demand for solving a substantial problem, the financing of retrofitting projects. (orig./CB) [Deutsch] Die Rekonstruktion alter Kraftwerke in Mittel- und Osteuropa ist eine Aufgabe von enormem Ausmass und grosser Bedeutung. Lebensdauerverlaengernde Massnahmen sind angesichts knapper Finanzen eine wirtschaftliche Alternative zum Anlagenneubau. Gute Marktchancen eroeffnen sich westlichen Firmen durch Kooperationen mit oestlichen Anlagenbauern, wie das Beispiel Siemens/KWU zeigt. Bei der Finanzierung von Projekten ist nach wie vor Phantasie gefragt. (orig.)

  14. Quantitative perfusion imaging by multi-slice CT in stroke patients; Quantitative Perfusionsbildgebung mittels Mehrschicht-Spiral-CT bei Patienten mit akuter zerebraler Ischaemie

    Energy Technology Data Exchange (ETDEWEB)

    Bohner, G.; Klingebiel, R. [Humboldt-Universitaet, Berlin (Germany). Universitaetsklinikum Charite, Abt. Neuroradiologie; Humboldt-Universitaet, Berlin (Germany). Universitaetsklinikum Charite, Inst. fuer Radiologie; Foerschler, A.; Lehmann, R. [Humboldt-Universitaet, Berlin (Germany). Universitaetsklinikum Charite, Abt. Neuroradiologie; Hamm, B. [Humboldt-Universitaet, Berlin (Germany). Universitaetsklinikum Charite, Inst. fuer Radiologie

    2003-06-01

    Infarktdemarkierung in der nativen CT erhielten eine CT-Perfusion (CTP) im Mittel 3,4 Stunden nach Symptombeginn an einem MS-CT Geraet (4 x 8 mm Scanvolumen). Die Parameterbilder der CTP (zerebrale Blutperfusion (CBP), zerebrales Blutvolumen (CBV) und mittlere Transitzeit (MTT)) wurden mittels eines parametrischen DA generiert und bezueglich einer zerebralen Minderperfusion verblindet durch zwei Neuroradiologen ausgewertet. Die Auspraegung und die Volumina der Perfusionsstoerungen wurden ermittelt und mit konventionellen bildgebenden Verlaufskonstrollen korreliert. Ergebnisse: Perfusionsbilder konnten von 44 Patienten generiert werden, hiervon entwickelten 22 Patienten einen im Verlauf gesicherten Infarkt. Ischaemische Veraenderungen konnten am besten anhand der MTT-Bilder (Sensitivitaet MTT 95%, CBP 91%, CBV 77%) erfasst werden. Die Spezifitaet war fuer die CBV-Bilder am hoechsten (100%). Patienten mit Infarkt zeigten seitenvergleichend eine signifikante (p<0,001) Reduktion der CBP (10,7 bzw. 38,3 ml/100 ml/min), des CBV (1,3 bzw. 2,3 ml/100 ml) und eine Verlaengerung der MTT (12,3 bzw. 4,3 s) in ischaemischen Arealen, wohingegen Patienten, die keinen Infarkt entwickelten, keine signifikante Seitendifferenz aufwiesen. Die Ausdehnung der CBV-Reduktion ergab die beste Korrelation (r=0,82) mit dem endgueltigen Infarktvolumen. Schlussfolgerung: Das in dieser Studie evaluierte DA-basierte CTP-Protokoll ist zur fruehzeitigen Erkennung und Quantifizierung einer akuten zerebralen Ischaemie geeignet. (orig.)

  15. C-arm computed tomography for transarterial chemoperfusion and chemo-embolization of thoracic lesions; Transarterielle Chemoperfusion und -embolisation thorakaler Neoplasmen mittels C-Arm CT

    Energy Technology Data Exchange (ETDEWEB)

    Vogl, T.J.; Naguib, N.N.; Nour-Eldin, N.E.; Lehnert, T.; Mbalisike, E. [Klinikum der Johann-Wolfgang-Goethe-Universitaet, Institut fuer Diagnostische und Interventionelle Radiologie, Frankfurt am Main (Germany)

    2009-09-15

    To evaluate the role of C-arm CT for on-line fluoroscopy in regional transarterial chemoperfusion (TACP) and chemo-embolization (TPCE) of primary and secondary malignant thoracic lesions. From September 2008 to March 2009 a total of 31 patients (20 males and 11 females, average age: 61.7 years, range 22-84 years) with 53 thoracic malignant lesions from different origins (primary or secondary pulmonary carcinoma n=37, pleural mesothelioma n=16) were treated with TACP or TPCE using flat-detector CT (FD-CT). C-arm CT of the latest generation was used to localize the lesion before local chemotherapy (Artis Zeego, Siemens, Erlangen). For TACP a 220 rotation and a volume of 150 ml (ratio of 1:2 contrast/normal saline), delay 2 s and flow 12 ml/s was used. For TPCE a volume of 75 ml (ratio of 1:2 contrast/normal saline), delay 2 s and flow 3 ml/s was used. TPCE C-arm CT allowed the evaluation of the degree of perfusion of the tumor and the geographic areas of enhancement correlated with the post-interventional lipiodol uptake in MSCT. In TACP the intercostal arteries involved could be visualized and in 30% of interventions the catheter had to be repositioned for the following intervention. C-arm CT provides additional information on the vascular characteristics and perfusion of pulmonary lesions resulting in a change of interventional strategy in a relevant number of patients. (orig.) [German] Ziel der Arbeit war die Evaluation der Wertigkeit der C-Arm CT fuer die online gesteuerte regionale transarterielle Chemoperfusion (TACP) und die transpulmonale Chemoembolisation (TPCE) primaerer und sekundaerer thorakaler Neoplasmen Von September 2008 bis Maerz 2009 wurden 31 Patienten (11 Frauen/20 Maenner, Durchschnittsalter 61,7 Jahre) mit 53 unterschiedlichen thorakalen Neoplasmen (primaere oder sekundaere Lungenkarzinome [n=37], Pleuramesotheliome [n=16]) mittels TACP oder TPCE unter Einsatz der Flachdetektortechnologie (FD-CT) behandelt. Alle Behandlungen erfolgten an einem C

  16. ORC-mall scale power plant

    Energy Technology Data Exchange (ETDEWEB)

    Jokinen, T. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Electromechanics

    1998-12-31

    In the conversion of low temperature heat into electricity, the greatest efficiency is obtained by using a Rankine cycle. The Organic Rankine cycle (ORC) is a Rankine cycle where an organic fluid is used instead of water as the working fluid. In the conventional ORC-solution, an axial turbine drives a standard generator through a high-speed gearbox. The system includes a separate feed pump, vacuum pump, lubrication system and requires several saft seals. The seals of the turbine have a limited working life in particular due to the high speed required. Thus, the entire present conventional ORC-plant is rather complicated and requires maintenance. To avoid these problems, a project was initiated at the Lappeenranta University of Technology to develop a high-speed, process fluid lubricated turbogenerator-feed pump as the prime mover of the ORC. The project has been continued in co-operation with the Helsinki University of Technology under the NEMO 2 program, the main goal being to build a demonstration power plant and to commercialise the project. The goals of the project were: (1) to model the ORC process, turbogenerator, and inverter, (2) to simulate the power plant in different normal and abnormal states, (3) to assess the advantages and disadvantages of various control systems, (4) to study network disturbances such as voltage and current harmonics and to research ways of reducing these disturbances, (5) to optimise heat exchanging surfaces and process parameters, and (6) to participate in the design of the demonstration power plant

  17. 微型燃气轮机浮环轴承动力学参数影响因素研究%Study of impact factor on dynamics parameters of the floating ring bearing for micro gas turbogenerator

    Institute of Scientific and Technical Information of China (English)

    沈那伟; 焦映厚; 陈照波; 马文生

    2012-01-01

    Floating ring bearings (FRBs) are widely used in high speed rotating machines. In this paper, the carrying capacity of outer oil film, which can represent the total capacity of FRBs, in floating-ring bearing was analyzed only because the bearing capacity of inner oil film is larger than that of the outer one. Based on the rotordynamic DyRoBes software and finite difference method, the pressure of outer oil film in relatively heavy load micro gas turbogenerator was computed and the results were analysed and compared. Because of the structural characteristics of FRBs , the relationship of stiffness and damping of inner and outer films is equivalent to the series of spring and damper, thus the total stiffness and damping of FRB could be calculated under different rotation speeds. The important parameters, such as eccentricity ratio, static balance position, which give the influences on the oil film characteristics and rotordynamic behavior were also studied. At last, the stability of oil film was determined using Routh-Hurwitz criterion.%浮环轴承在高速运转时内层油膜承载力大于外层油膜承载力,在分析浮环轴承稳态内外层油膜压力时,只分析外层油膜压力即可表现出浮环轴承的承载能力.利用转子动力学分析软件DyRoBes与有限差分方法分别对相对重载微型燃气轮机浮环轴承外层油膜压力Reynolds方程进行数值计算,分析并比较其运算结果.由于浮环轴承自身结构的特点,使得浮环轴承内外层油膜刚度和阻尼的相互关系等效于弹簧和阻尼的串联,由此可以算出不同转速下的浮环轴承油膜总刚度和总阻尼及偏心比、轴颈的静平衡位置等影响浮环轴承油膜特性及动力学行为的重要参数,最后利用Routh-Hurwitz判别法分析了对应转速下的油膜稳定性.

  18. Monitoring of the production quality of fibre-reinforced pressure vessels using acoustic emission testing; Ueberwachung der Fertigungsqualitaet von Faserverbund-Druckbehaeltern mittels Schallemissionspruefung

    Energy Technology Data Exchange (ETDEWEB)

    Duffner, Eric; Gregor, Christian; Bohse, Juergen [BAM Bundesanstalt fuer Materialforschung und -pruefung, Berlin (Germany)

    2011-07-01

    mit metallischem Liner getestet und patentiert werden [2]. Mit den aktuellen Untersuchungen wurde die Moeglichkeit des Erkennens von Fertigungsfehlern in Kohlenstofffaser/Glasfaser - Hybriddruckbehaeltern mit polymerem Liner evaluiert. Dazu wurden Faserverbund - Druckbehaelter mittels Schallemissionsmessung bei einer hydraulischen Erstdruckpruefung ueberwacht, wie sie (ohne Schallemissionspruefung) generell zur Qualitaetssicherung nach der Fertigung von Faserverbund - Druckbehaeltern gefordert wird. An Druckbehaeltern aus einer Serienproduktion wurden die Schallemissionsverlaeufe registriert und die mittleren Merkmalswerte sowie deren Streuung als Referenz ermittelt. Diese werden mit den Schallemissionsverlaeufen von Druckbehaeltern mit gezielt eingebrachten Fertigungsfehlern verglichen. Bei den Fertigungsfehlern handelt es sich um Fehler, die in der Serienproduktion auftreten koennen und mit den Methoden der herkoemmlichen Qualitaetssicherung schwer oder gar nicht nachzuweisen sind. Alle untersuchten Druckbehaelter wurden im Anschluss an die Erstdruckpruefung auf verschiedene Weise bis zum Versagen (Leckage, Bersten) beansprucht. Damit war es moeglich, den tatsaechlichen Einfluss der Fertigungsfehler auf den Berstdruck bzw. das Ermuedungsverhalten der Behaelter zu verifizieren und die Aussagefaehigkeit des Schallemissionsverfahrens zu beurteilen.

  19. Dynamic Balancing of the Shaft System for a Domestic 600 MW Turbo-Generator Set%国产600MW汽轮发电机组轴系动平衡研究

    Institute of Scientific and Technical Information of China (English)

    何国安; 闵昌发; 张学延; 张卫军; 王延博

    2012-01-01

    针对国产600MW汽轮发电机组运行中普遍存在的轴系异常振动问题,分析了振动现象、振动特征、振动机理及其原因,并对现场动平衡问题的处理方法进行了总结.结果表明:国产600MW高中压转子由于结构不对称存在较大的振型干扰,现场对转子进行动平衡时应考虑各阶振型的干扰系数,尤其是一阶配重对二阶振型的影响;部分机组低压转子轴承座振动超标的原因为采用坐缸式轴承座的支承刚度不足,现场可以通过精细动平衡来消除;发电机转子振动主要呈现三阶振型,现场校正三阶不平衡的方法就是在低-发对轮或发-励对轮上加重,且在动平衡分析时应注意区分振型畸变;集电小轴的振动受发-励对轮的安装工况影响较大,现场对其进行动平衡分析时应考虑发-励对轮下张口对加重响应的影响.%Aiming at the vibration problems frequently occurring in operation of domestic 600 MW turbo-generator sets,an analysis has been carried out on the vibration phenomenon,feature,mechanism and the causes,while various countermeasures for on-site dynamic balancing summarized.Results show that large vibration disturbance exists in domestic 600 MW high-and medium-pressure rotors due to their asymmetric structures,to overcome which,the disturbance coefficient of various vibration modes and orders should be considered during on-site dynamic balancing process of rotors,especially the influence of one-order weighing on two-order vibration mode.The abnormal vibration occurring in low-pressure cylinder of some domestic sets are caused by insufficient rigidity of supports for relevant bearing seats,which may be handled by fine dynamic balancing on site.The vibration of generator rotor is mainly of the three-order mode,which may be corrected by adding balancing weight on the shaft coupling between low-pressure rotor and generator rotor,or on the shaft coupling between generator rotor and exciter

  20. Verfestigung asymmetrischer Beziehungsstrukturen mittels Gewalt

    Directory of Open Access Journals (Sweden)

    Daniel Osterwalder

    2004-07-01

    Full Text Available Die Arbeit der Historikerin Claudia Töngi dreht sich um verschiedene Formen von Gewalt wie Tötungsdelikte, häusliche und sexuelle Gewalt. Auf der Basis einer umfangreichen Daten- und Quellensammlung aus dem Gerichtsarchiv des Schweizer Kantons Uri (die zudem im Anhang aufgeführt wird zeigt sie, wie sich im 19. Jahrhundert Frauen und Männer zur Anwendung von Gewalt stellten und wie sich Gewaltpraktiken und deren Wahrnehmung im besprochenen Zeitraum verändert haben. Einerseits bringt Claudia Töngi noch unpublizierte Archivakten vor dem Hintergrund sozialgeschichtlicher Fragestellungen zum Sprechen, andererseits ermöglicht sie interessierten Forscher/-innen, die vergleichend zu Gewalt und Delinquenz arbeiten, raschen Zugriff auf die urnerischen Daten. Die Untersuchung wurde als Projekt Nr. 15 im Rahmen des Nationalfondsprogramms „Gewalt im Alltag und organisierte Kriminalität“ (NFP 40; URL: http://www.nfp40.ch, 20.04.2004 durchgeführt.

  1. Frauen. Kultur. Mittel- und Osteuropa oder: Über den langsamen Einzug der gender studies in die slawistischen Kulturwissenschaften Women. Culture. Middle and Eastern Europe or: On the Slow Introduction of gender studies into the Slavonic Cultural Sciences

    Directory of Open Access Journals (Sweden)

    Barbara Wurm

    2001-03-01

    Full Text Available Der vorliegende Sammelband, entstanden anläßlich einer Konferenz, die im September 1997 vom Institut für Slawistik der Universität Innsbruck in Zusammenarbeit mit der österreichischen UNESCO-Kommission veranstaltet wurde, untersucht aus soziologischer, kulturhistorischer, literatur- und filmwissenschaftlicher Perspektive verschiedenste Aspekte der Institutionalisierung und Repräsentation von „Frauen in der Kultur“ Mittel- und Osteuropas.This anthology, the result of a conference organized in September 1997 by the Institute for Slavonic studies at the University of Innsbruck in co-operation with the Austrian UNESCO commission, examines various aspects of the institutionalization and representation of women in Middle and Eastern European culture from a sociological and cultural historical perspective and from that of literary and film sciences.

  2. Postoperative evaluation of the position of interference screws, boneblocks and ligamentum patellae autografts in anterlor cruciate ligament replacement; Evaluierung von Knochenblockposition, Interferenzschraubenlage und Ersatzplastik des vorderen Kreuzbandes nach Ligamentum patellae-Transplantat mittels CT

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, R, [Leipzig Univ. (Germany). FUSt 8/Radiologie; Kolbus, F.; Brueckner, B. [Leipzig Univ. (Germany). Abt. 2/Chirurgie des Bundeswehrkrankenhauses Leipzig

    2000-06-01

    Purpose: Evaluation of arthroscopically assisted reconstruction of the anterior cruciate ligament using ligamentum patellae autografts in the bone-tendon-bone technique with special regard to the position of blocks and interference screws. Material and methods: In a prospective study 28 patients were included after undergoing arthroscopic anterior cruciate ligament replacement surgery. Data thus obtained were correlated with the postoperatively determined functional parameters of the affected joint. Results: Interference screws, bone-blocks and ligamentous transplants could be well imaged using CT. In a comparison of our data with clinical results there was a statistically highly significant correlation between clinical outcome and the position of bone-blocks and interference screws in the tibia. Angles between screw and bone-block exceeding a standard deviation led to significantly worse results, while a divergence in femoral angles did not lead to significantly worse results. (orig./AJ) [German] Ziel: Evaluation der arthroskopischen Ersatzplastik des vorderen Kreuzbandes unter besonderer Beruecksichtigung der Lage der Knochenbloecke, Interferenzschrauben und Bohrkanaele mittels CT und Vergleich der radiologischen Daten mit klinischen und funktionellen Parametern. Material und Methodik: In einer prospektiven Studie wurden 28 Patienten nach arthroskopischer Ersatzplastik des vorderen Kreuzbandes mittels Lig. patellae-Transplantat im CT untersucht. Anschliessend erfolgte die Pruefung der Korrelation mit postoperativ erhobenen klinisch-funktionellen Parametern des Kniegelenks. Ergebnisse: Die Interferenzschrauben, Bohrkanaele und Knochenbloecke sowie das Transplantat konnten in allen Faellen gut dargestellt werden. Bei einem Vergleich unserer Daten mit den klinischen Untersuchungsergebnissen der Chirurgen zeigte sich ein statistisch hochsignifikanter Zusammenhang mit den Winkeldivergenzen zwischen Interferenzschraube und Bohrkanal im Bereich der Tibia. Divergenzen

  3. DMSA-scintigraphy in paediatrics: is the evaluation of the geometric mean necessary for the calculation of the differential renal function?; Partialfunktionsberechnung der Nieren mit DMSA in der Paediatrie: ist fuer die Bestimmung das geometrische Mittel notwendig?

    Energy Technology Data Exchange (ETDEWEB)

    Porn, U.; Alalp, S.; Fischer, S.; Dresel, S. [Klinik und Poliklinik fuer Nuklearmedizin, Klinikum der Ludwig-Maximilians-Univ. Muenchen (Germany); Rossmueller, B. [Inst. fuer Radiologische Diagnostik, Klinikum der Ludwig-Maximilians-Univ. Muenchen (Germany); Hahn, K. [Klinik und Poliklinik fuer Nuklearmedizin, Klinikum der Ludwig-Maximilians-Univ. Muenchen (Germany); Inst. fuer Radiologische Diagnostik, Klinikum der Ludwig-Maximilians-Univ. Muenchen (Germany)

    2001-08-01

    cases with an obvious anatomical abnormality. (orig.) [German] Bei der statischen Nierenfunktionsszintigraphie mit Tc-99m-Dimercaptobernsteinsaeure (DMSA) wird zur moeglichst exakten Bestimmung der seitengetrennten Partialfunktion (PF) die Berechnung des geometrischen Mittels aus dorsaler und ventraler Projektion empfohlen. Ziel unserer Untersuchung war es, die allein aus der dorsalen Projektion ermittelte Partialfunktion (PF{sub dors}) mit der aus dem geometrischen Mittel berechneten PF (PF{sub geom}) zu vergleichen, um die Notwendigkeit der zusaetzlichen ventralen Projektion zu ueberpruefen. Methode: Es wurden 164 DMSA-Untersuchungen von 151 Kindern (86 w, 65 m) mit einem Alter von 16 d bis 16 a (4,7 {+-} 3,9 a) ausgewertet. Die Akquisition erfolgte mit einer Doppelkopfkamera aus ventraler und dorsaler Projektion (Picker Prism 2000 XP, LEUHR, Matrix: 256 x 256, 300 kcts/view, Zoom: 1,6-2,0). Mittels ROI-Auswertung wurden die Hintergrund-korrigierten Zaehlraten der beiden Nieren von ventral und dorsal bestimmt und die dorsalen Zaehlratenverhaeltnisse mit dem geometrischen Mittel (SQR[Cts{sub dors} x Cts{sub ventr}]) verglichen. Ergebnisse: Die PF{sub dors} ergab statistisch signifikant niedrigere Werte fuer die rechte Niere (bzw. entsprechend hoehere Werte fuer die linke Niere) im Vergleich zur PF{sub geom} (p<0,01). Die mittlere Differenz zwischen der PF{sub geom} und der PF{sub dors} betrug 1,5 {+-} 1,4%. Nur in 6/164 Faellen (3,7%) ergab sich ein Unterschied von {>=}5% (5,0-9,5%). Bei 3 dieser 6 Faelle lag die mit der PF{sub dors} unterschaetzte Niere (2 x links, 1 x rechts) kaudal dystop. Die uebrigen 3 Patienten mit einer Differenz von >5% zeigten keine Lage- oder Strukturanomalie. Schlussfolgerung: Die Berechnung der Partialfunktion ausschliesslich aus den dorsalen Projektionen fuehrt im Vgl. zur Berechnung durch das geometrische Mittel zu einer Unterschaetzung der PF der rechten Niere im Vergleich zur linken Niere. Dieser Effekt fuehrt jedoch bei orthotop

  4. Calculation and analysis of slot pitch coefficient of turbo-generator rotor with magnetic and non-magnetic slot wedges%具有磁性和非磁性槽楔的汽轮发电机转子槽分度的计算与分析

    Institute of Scientific and Technical Information of China (English)

    薛易; 王立坤; 韩继超; 李伟力

    2016-01-01

    为了研究汽轮发电机转子不同槽分度对电机电磁场的影响,以150 WM空冷汽轮发电机为例,建立了汽轮发电机的二维数学模型和物理模型。采用二维有限元方法,计算了转子带有非磁性槽楔和磁性槽楔时不同槽分度下的电磁场及发电机的饱和电抗值,并在此基础上研究了不同槽分度情况下非磁性和磁性材料的3种转子槽楔对发电机定、转子损耗的影响。计算结果表明,转子采用弱磁性槽楔和导磁导电的Fe-Cu合金槽楔后,发电机的饱和同步电抗相对于铝合金槽楔对应的饱和同步电抗减小,同时可以有效减小气隙磁密中的谐波含量,降低表面损耗。计算结果为发电机转子磁性槽楔和槽分度的选择设计提供了理论依据。%A 150 WM air-cooled turbo-generator was taken as an example to investigate the effects of dif-ferent slot pitch coefficients of the turbo-generator rotor on electromagnetic field. First, the 2D mathemat-ical model and physical model of the turbo-generator was established. Adopting 2D finite-element meth-od, the saturation reactance value and electromagnetic field of different slot pitch coefficients were calcu-lated when magnetic and non-magnetic slot wedges were used on the generator rotor, respectively. Mean-while, under the condition of applying different slot pitch coefficients, the magnetic and non-magnetic material of three kinds of rotor slot wedge were studied on the influence of the generator stator losses and rotor losses. The results show that the rotor with weak magnetic slot wedge and magnetic conductive Fe-Cu alloy slot wedge reduces the harmonic of air-gap flux density effectively and the surface losses. At the same time, the generator of saturation synchronous reactance relative to the aluminum slot wedge corre-sponding saturation synchronous reactance is reduced. The results present theoretical basis for selection and design of magnetic slot wedge

  5. Study of Intelligent Fault Diagnosis Method for Turbo-generator Unit Based on Support Vector Machine and Knowledge%基于支持向量机与知识的汽轮发电机组智能故障诊断研究

    Institute of Scientific and Technical Information of China (English)

    黄乃成; 顾煜炯; 谢骐宇; 张国坤

    2012-01-01

    For the low efficiency and poor accuracy of turbogenerator unit's fault diagnosis, this paper divides the common 18 kinds of vibration fault into four categories, and takes advantage of support vector, machine to distinguish the fault cluster for early fault diagnosis according to the characteristics of vibration signal spectrum. For different fault cluster, different fault pattern recognition model is established. With the use of certain symptom group, this article engages in knowledge reasoning to obtain the specific fault recognition mode by using weighted fuzzy logic. Besides, the searching methods of fault cause, fault influence and troubleshooting measures in the knowledge base are proposed, which make the diagnosis process more meticulous and comprehensive. Case analysis shows that it is feasible to use this method to develop a system for intelligent fault diagnosis of turbo-generator unit, which is valuable for further study in more depth.%针对汽轮机组故障诊断效率与准确率不高的问题,把常见的18种振动故障划分为4类,利用支持向量机对振动信号的频谱进行故障类识别,实现故障的初诊断.对不同类故障建立不同的故障模式识别模型,采用特定的征兆群运用加权模糊逻辑进行知识推理诊断出具体故障模式.提出了故障原因、故障影响和故障处理措施在知识库中的查找方法,使得诊断过程更加细致全面.案例分析表明该方法是有效可行的,对汽轮发电机组智能故障诊断系统的设计具有借鉴意义和深入研究的价值.

  6. Reduction of radiation dose by using digital luminescence radiography compared to conventional screen film system with grid cassette; Reduktion der Strahlendosis mittels Speicherfolienradiographie im Vergleich zum konventionellen Film-Folien-System mit Rasterkassette am Schaedelphantom

    Energy Technology Data Exchange (ETDEWEB)

    Heyne, J.P.; Merbold, H.; Neumann, R.; Freesmeyer, M.; Jonetz-Mentzel, L.; Kaiser, W.A. [Friedrich-Schiller-Univ. Jena, Inst. fuer Diagnostische und Interventionelle Radiologie (Germany); Sehner, J. [AGFA-Deutschland, Vertriebsgesellschaft (Germany)

    1999-07-01

    mittels RK und digital (ADC-70, Agfa) a.p. geroentgt. Bei konstanter Spannung wurde das mAs-Produkt stufenweise gesenkt und dabei die Eintrittsdosis mittels Halbleiterdetektor des Dosimax (Wellhoefer) ermittelt. 5 Untersucher beurteilten die Aufnahmen nach charakteristischen Bildmerkmalen, kritischen Strukturen, Ortsaufloesung und Bildkontrast. Ergebnisse: Die Eintrittsdosis betrug bei 73 kV/22 mAs konventionell (Rasterkassette) 0,432 mGy und digital 0,435 mGy. Bis zu einer durchschnittlichen Dosis von 71% (0,308 mGy; SD 0,050) waren die Aufnahmen sehr gut und bis zu einer durchschnittlichen Dosis von 31% (0,136 mGy; SD 0,065) ausreichend beurteilbar. Die erkennbaren Linienpaare/mm auf dem Bleistrichraster reduzierten sich dabei untersucherabhaengig bis zu 2 Stufen. Der Bildkontrast war sehr gut bis ausreichend. Die Akzeptanz der nachverarbeiteten Aufnahmen war individuell verschieden und erbrachte nur in hoeheren Dosisbereichen eine verbesserte Beurteilbarkeit der Knochenstrukturen und des Kontrastes. Schlussfolgerung: Fuer die ausreichende Beurteilbarkeit einer moeglichen Fraktur/der Nasennebenhoehlen/zur Vermessung kann die Dosis auf mindestens 56% (Durchmesser 31%; SD 14,9%)/40% (Durchmesser 27%; SD 9,3%)/18% (Durchmesser 14%; SD 4,4%) gesenkt werden. Mittels digitaler Radiografie wird damit bei 73 kV ein fragestellungsbezogenes mAs-Produkt moeglich und angegeben, so z.B. zum Frakturausschluss 73 kV/12,5 mAs und zur Schaedelvermessung 73 kV/4 mAs. (orig.)

  7. Cortical motor hand area. Validation of functional magnetic resonance imaging by intraoperative cortical stimulation mapping; Das motorische Handareal. Nichtinvasiver Nachweis mittels fMRT und operative Validierung mit kortikaler Stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Yousry, T. [Inst. fuer Radiologische Diagnostik, Klinikum Grosshadern, Univ. Muenchen (Germany); Schmid, U.D. [Neurochirurgische Klinik, Klinikum Grosshadern, Univ. Muenchen (Germany); Schmidt, D. [Inst. fuer Radiologische Diagnostik, Klinikum Grosshadern, Univ. Muenchen (Germany); Heiss, D. [Inst. fuer Radiologische Diagnostik, Klinikum Innenstadt, Univ. Muenchen (Germany); Jassoy, A. [Inst. fuer Radiologische Diagnostik, Klinikum Innenstadt, Univ. Muenchen (Germany); Eisner, W. [Neurochirurgische Klinik, Klinikum Grosshadern, Univ. Muenchen (Germany); Reulen, H.J. [Neurochirurgische Klinik, Klinikum Grosshadern, Univ. Muenchen (Germany); Reiser, M. [Inst. fuer Radiologische Diagnostik, Klinikum Grosshadern, Univ. Muenchen (Germany)

    1995-04-01

    In this study, activation of cortical sites by specific motor tasks (opening and closing of the hand) was examined by fMRI utilizing the blood-oxygen-level-dependent (BOLD) technique. fMRI was employed in five volunteers and in six patients with tumors in the vicinity of the central region. In the patients, the fMRI data and intraoperative cortical mapping were compared. Our results indicate good correlation of these two methods and that there are no significant differences in the localization of the motor hand area. (orig.) [Deutsch] Die funktionelle Magnetresonanztomographie (fMRT) ermoeglicht die nichtinvasive Lokalisation bestimmter Hirnfunktionen mit hoher raeumlicher Aufloesung. Um zu ueberpruefen, ob die mittels fMRT dargestellten Signalintensitaetsaenderungen wirklich dem Repraesentationsareal einer definierten Funktion entspricht, verglichen wir bei einem Patientenkollektiv die Resultate der fMRT mit den Ergebnissen der intraoperativen motorischen Kortexstimulation. Es zeigte sich, dass Lokalisation und Ausdehnung des von uns untersuchten motorischen Handareals bei beiden Methoden uebereinstimmte. Unsere Ergebnisse zeigen, dass die kortikale Repraesentation des motorischen Handareals durch fMRT mit hoher raeumlicher Aufloesung und nichtinvasiv lokalisiert werden kann. (orig.)

  8. Case report: massive lower intestinal bleeding from ileal varices. Treatment with transjugular intrahepatic portosystemic shunt (TIPSS); Fallbericht: Massive untere gastrointestinale Blutung aus ilealen Varizen. Behandlung mittels transjugulaerem intrahepatischem portosystemischem Shunt (TIPSS)

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Benitez, R. [Universitaetsklinikum Heidelberg (Germany). Abteilung fuer Diagnostische und Iinterventionelle Radiologie; Universitaetsklinikum, Abteilung fuer Diagnostische und Interventionelle Radiologie, Heidelberg (Germany); Seidensticker, P.; Richter, G.M.; Stampfl, U.; Hallscheidt, P. [Universitaetsklinikum Heidelberg (Germany). Abteilung fuer Diagnostische und Iinterventionelle Radiologie

    2007-05-15

    Acute gastrointestinal bleeding in patients with liver cirrhosis is associated with a high mortality. Ileal varices and collaterals from ectopic vessels are extremely rare, encountered in less than 5% of the cirrhotic patients. The diagnosis is frequently delayed because the regular diagnostic methods such as gastroscopy or colonoscopy are unsuccessful in accurate the source of bleeding in the majority of the cases. We report an unusual case of massive and uncontrollable lower intestinal bleeding from ileal varices with right ovarian vein anastomosis in a 56 year-old female patient with liver cirrhosis and previous history of abdominal and pelvic surgery. The accurate angiographic and computed tomography diagnosis allowed fast decompression of the portal venous system using a transjugular intrahepatic portosystemic shunt. (orig.) [German] Akute gastrointestinale Blutungen sind bei Leberzirrhosepatienten mit einer hohen Mortalitaet verbunden. Ileale Varizen und Kollateralen aus anderen ektopen Gefaessen des Darms sind extrem selten und treten bei weniger als 5% aller Zirrhosepatienten auf. Die Diagnosestellung erfolgt oft verspaetet, da die ueblichen diagnostischen Untersuchungsmethoden wie Gastroskopie oder Koloskopie in den meisten Faellen die Blutungsquelle nicht ausreichend darstellen. Wir berichten ueber einen ungewoehnlichen Fall von massiver und unkontrollierbarer unterer gastroinstestinaler (GI-)Blutung aus ilealen Varizen mit Verbindung zur rechten V. ovarica einer 56-jaehrigen Frau, bei der anamnestisch eine Leberzirrhose und abdominelle Operationen sowie Operationen im Bereich des Beckens bekannt waren. Die genaue angiographische und computertomographische Diagnose erlaubte eine rasche Dekompression des Portalvenensystems mittels eines transjugulaeren portosystemischen Shunts. (orig.)

  9. Performance of the Castelnuovo Valdicecina (Italy) 1-1.5 megawatt ORC and discussion of applications for binary modular units

    Energy Technology Data Exchange (ETDEWEB)

    Bini, R.; Girardi, P. [Turboden, Brescia (Italy); Gaia, M. [Politecnico di Milano, Milan (Italy); Sabatelli, F. [Ente Nazionale per l`Energia Elettrica, Pisa (Italy). Centro di Ricerca Geotermica

    1994-12-31

    In the paper the use of binary power plant cycle units for low enthalpy geothermal source exploitation is discussed. Binary power cycles operating in accord with the Organic Rankine Cycle (ORC) concept allow to produce electricity from heat sources like hot water or low pressure steam with high gas content. Geothermal fluids having temperatures as low as 100 degree celsius and less can be utilized with thermodynamic conversion efficiencies and economic cost effectiveness not obtainable with other traditional systems. In these units the conversion of geothermal heat to electricity is obtained by vaporizing a suitable high molecular mass organic fluid and expanding the vapour in a turbine, which remains clean and efficient all through the machine life while the scaling is confined to the easy-to-clean heat exchanger tubes. The chief advantages of this technology are described together with the main fields of application. A 1.3 MW ORC turbogenerator recently installed and tested at Castelnuovo V.C. near Larderello, is described and the performance obtained are discussed as well as the economic effectiveness of both the Castelnuovo machine and a smeller size (all mounted on a 40 feet standard skid) modular unit. (Authors). 8 refs., 10 figs.

  10. Experimental determination of the electronic properties of application-relevant interfaces of organic semiconductors by means of photoelectron spectroscopy; Experimentelle Bestimmung der elektronischen Eigenschaften anwendungsrelevanter Grenzflaechen organischer Halbleiter mittels Photoelektronenspektroskopie

    Energy Technology Data Exchange (ETDEWEB)

    Grobosch, Mandy

    2009-07-01

    This thesis under the titel Experimental Determination of the Electronic Properties of Application-relevant Interfaces of Organic Semiconductors by means of Photoelectron Spectroscopy was drawn up at the Leibniz Institute for Solid-State and Materials Research (IFW) Dresden at the Institute for Solid-State Research (IFF) under the maintenance of Prof. Dr. B. Buechner. To the scientific study hereby came two types of application-relevant interfaces. On the one hand the influence of the electrode preparation under normal conditions by means of ex-situ purification procedures in comparison to in-situ prepared contacts on the electronic behaviour of the organic semiconductor sexithiophene on interfaces to metallic substrates was studied. As substrate materials hereby the metals silver, palladium, gold, and platinum came to application. In a second study the interfaces of the organic semiconductors sexithiophene and copper(II)-phthalocyanine in contact to thin films of the transition-metal oxide La{sub 0.7}Sr{sub 0.3}MnO{sub 3} were studied. Also here a comparing study for ex-situ and in-situ purificated La{sub 0.7}Sr{sub 0.3}MnO{sub 3} contacts was performed. The films applied for this were fabricated in the IWF Dresden at the Institute for Metallic Materials (IMW). Also in the framework of these studies the influence of oxygen on the electronic and chemical behaviour on the interfaces held the spotlight. [German] Diese Dissertation unter dem Titel Experimentelle Bestimmung der elektronischen Eigenschaften anwendungsrelevanter Grenzflaechen organischer Halbleiter mittels Photoelektronenspektroskopie wurde am Leibniz Institut fuer Festkoerper- und Werkstoffforschung (IFW) Dresden am Institut fuer Festkoerperforschung (IFF) unter der Betreuung von Prof. Dr. B. Buechner angefertigt. Zur wissenschaftlichen Untersuchung kamen hierbei zwei Typen anwendungsrelevanter Grenzflaechen. Zum einem wurde der Einfluss einer Elektrodenpraeparation unter Normalbedingungen mittels ex

  11. Inflammatory aortic arch syndrome: contrast-enhanced, three-dimensional MR - angiography in stenotic lesions; Entzuendliches Aortenbogensyndrom: Stenosediagnostik mittels kontrastmittelverstaerkter 3D-MR-Angiographie im Vergleich mit der DSA

    Energy Technology Data Exchange (ETDEWEB)

    Both, M.; Mueller-Huelsbeck, S.; Biederer, J.; Heller, M.; Reuter, M. [Universitaetsklinikum Schleswig-Holstein, Kiel (Germany). Klinik fuer Diagnostische Radiologie; Reinhold-Keller, E.; Gross, W.L. [Rheumaklinik Bad Bramstedt GmbH (Germany)

    2004-01-01

    verglichen. Ergebnisse: Es erfolgte die Untersuchung von insgesamt 467 Gefaessterritorien, in denen mittels DSA 50 Stenosen und 35 Verschluesse nachgewiesen wurden. Saemtliche Laesionen wurden in der MRA detektiert, der Stenosegrad wurde bei 23 Segmenten ueberschaetzt. Sensitivitaet und Spezifitaet der MRA betrugen 100 bzw. 94,3%, positiver und negativer Vorhersagewert 73,6% bzw. 100% bei einer Genauigkeit von 95,1%. Schlussfolgerung: Die kontrastmittelverstaerkte 3D-MRA stellt trotz einer Tendenz zur Ueberschaetzung des Stenosegrades ein aussagekraeftiges, nicht invasives Verfahren fuer die Diagnostik des entzuendlichen Aortenbogensyndroms dar. (orig.)

  12. Separation of uranium from aqueous solutions using calix[6]arenes in liquid-liquid extraction as well as solid phase extraction; Abtrennung von Uran aus waessriger Loesung durch Calix[6]arene mittels Fluessig-Fluessig-Extraktion sowie Festphasen-Extraktion

    Energy Technology Data Exchange (ETDEWEB)

    Schmeide, K.; Geipel, G.; Bernhard, G.

    2004-11-01

    The suitability of different calyx[n] arene types for uranyl extraction from liquid solutions was examined by means of liquid-liquid extraction using aqueous phases and organic solvents of varying compositions. It was found that COOH-derivatised calyx[6] arenes have good extraction properties and can even be used in the acid pH range. The use of calixarene-modified fleeces for the separation of uranyl from aqueous phases was examined in batch experiments with pH and uranyl concentration as variables and in the presence or absence of competing ions. The results showed that calixarene-modified fleeces can be used for uranium separation starting from pH 4. At pH 5, up to a maximum of 7.6 x 10{sup -7} mol uranium can be bound per 1 g of calixarene-modified fleece. The separation of uranyl from synthetic pit waters was examined as a means of testing the separation capacity of calixarene-modified fleeces in environmentally sensitive waters. Studies on the reversibility of uranium bonding to calixarene-treated polyester fleeces have shown that under environmentally realistic conditions (neutral pH range) the uranium is firmly bound to the calixarene-modified fleeces and cannot be mobilised. By contrast, in acidic environments calixarene-modified fleeces are capable of near-complete regeneration. Such regenerated textile filter materials can then be used for further uranium separation cycles. [German] Die Eignung verschiedener Calix[n]aren-Typen fuer die Uranylextraktion aus waessriger Loesung wurde mittels Fluessig-Fluessig-Extraktion unter Variation der Zusammensetzung der waessrigen Phase und des organischen Loesungsmittels untersucht. Es konnte gezeigt werden, dass COOH-derivatisierte Calix[6]arene gute Extraktionseigenschaften aufweisen und selbst im sauren pH-Bereich angewendet werden koennen. Die Uranylabtrennung aus waessriger Loesung durch calixarenmodifizierte Vliese wurde in Abhaengigkeit des pH-Wertes und der Uranylkonzentration in Abwesenheit und Gegenwart von

  13. Development of new heterogeneous catalysts for the decomposition of methanol into hydrogen and carbon monoxide applying high throughput methods; Entwicklung neuer heterogener Katalysatoren zur Spaltung von Methanol in Wasserstoff und Kohlenmonoxid mittels Hochdurchsatz-Methoden

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, Torsten

    2008-07-11

    The topic of this thesis has been the development of new heterogeneous catalysts for the decomposition of methanol into hydrogen and carbon monoxide. As an important constraint here, the content of noble metals of the catalysts should be as low as possible. High-throughput-methods were applied in some of the syntheses and experiments to accelerate the development, as, for example, the use of liquid based sol-gel syntheses and the examination of catalyst libraries by spatial resolution gas chromatography. This screening technique allowed to test up to 207 different substances during one single experiment. Then, different combinatorial strategies were applied. First, these methods led to a highly active and stable catalyst in the ternary system of Cu-Ni-Zn, which showed high conversion and selectivity comparable to an industrial reference catalyst. Its activity during an 18 hour long term run was constant in contrast to the reference. Second, an additional approach starting from a broader variety of elements led to a Ce- Ru- and to a Cr-Ru-catalyst. Both of them were highly active in short term experiments, but lost their outstanding performances during long term runs. (orig.) [German] Die vorliegende Arbeit befasste sich mit der Entwicklung neuer heterogener Katalysatoren fuer die Spaltung von Methanol zu Wasserstoff und Kohlenmonoxid, die einen moeglichst geringen Gehalt an Edelmetallen aufweisen sollten. Um diesen Prozess zu beschleunigen, wurden in einem Teil der Synthesen und Experimente Hochdurchsatzmethoden verwendet. Neben der Roboter gestuetzten Sol-Gel-Synthese umfasste dies die Untersuchung von Katalysatorbibliotheken mittels ortsaufgeloester Gaschromatographie, die es ermoeglichte, in einem Experiment bis zu 207 verschiedene Substanzen auf ihre katalytische Aktivitaet zu testen. Unter Anwendung verschiedener kombinatorischer Strategien wurde zunaechst ein sehr aktiver und stabiler Katalysator im ternaeren Cu-Ni-Zn-System entdeckt. Neben Umsaetzen und

  14. Verification of MR thermometry via in-vivo intralesional fluoroptic temperature measurement for laser-induced thermotherapy of liver metastases; Verifizierung der MR-Thermometrie mittels in vivo intralaesionaler, fluoroptischer Temperaturmessung fuer die laserinduzierte Thermotherapie von Lebermetastasen

    Energy Technology Data Exchange (ETDEWEB)

    Vogl, T.J.; Weinhold, N.; Mack, M.G.; Mueller, P.K.; Scholz, W.R.; Straub, R.; Felix, R. [Humboldt-Universitaet, Berlin (Germany). Strahlenklinik und Poliklinik; Roggan, A. [Laser- und Medizin-Technologie gGmbH, Berlin (Germany)

    1998-08-01

    To evaluate the correlation of MR-measured changes of signal intensity and invasive fluoroptic temperature measurements during MR-guided LITT of liver metastases. Results: In both sequences a gradually increasing signal loss could be documented during laser application which proved to be reversible after cessation of energy deposition. The percentage of decrease in signal intensity correlated directly with the measured increase of temperature. Invasive fluoroptical evaluation of temperature distribution after 10 min exposure time showed at 5 mm distance from the applicator an increase of temperature of 35 C, in 1O mm distance a mean increase of 9 C{+-}1.7, in 15 mm a mean increase of 7 C{+-}1.6 and in 20 mm a mean increase of 3 C{+-}0.5. This is evidence of thermal tissue damage up to 3 cm in diameter with laser monoapplication. The qualitative evaluation revealed a reproducible correlation of the extent of signal loss around the applicator and the finally induced degree of necrosis. Conclusion: Invasive fluoroptical temperature measurements prove the diagnostic reliability of MR thermometry for the online monitoring of LITT of liver metastases. (orig.) [Deutsch] Verifizierung der MR-Thermometrie mittels invasiver fluoroptischer, intralaesionaler Temperaturmessung fuer die laserinduzierte Thermotherapie von Lebermetastasen. Ergebnisse: Beide MR-Thermometrie-Sequenzen konnten einen zunehmenden Signalverlust um den Applikator waehrend der Laserapplikation dokumentieren, reversibel nach Ende der Energiezufuhr. Die invasive fluoroptische Temperaturmessung nach einer Expositionsdauer von 10 min zeigte in 5 mm Entfernung vom Applikator den hoechsten mittleren Temperaturanstieg ({Delta}T) von 35 C, in 10 mm Distanz war {Delta}T= 9 C{+-}1,7, in 15 mm Distanz 7 C{+-}1,6 und in 20 mm Distanz 3 C{+-}0,5. Die prozentuale Signalintensitaetsabnahme korrelierte mit dem gemessenen Temperaturanstieg. Diese Resultate bestaetigten die Ausdehnung der thermischen Gewebeschaedigung von

  15. Metal recovery via geobiotechnology; Metallgewinnung mittels Geobiotechnologie

    Energy Technology Data Exchange (ETDEWEB)

    Hedrich, Sabrina; Schippers, Axel [Bundesanstalt fuer Geowissenschaften und Rohstoffe (BGR), Hannover (Germany). Fachbereich Geochemie der Rohstoffe

    2017-02-15

    Specialized acidophilic bacteria and archaea are able to extract valuable metals such as copper, gold, cobalt, nickel, zinc, and uranium from sulfide ores. This process is known as bioleaching and its application in the mining industry as biomining. Laboratory studies also demonstrated bioleaching of oxide ores such as laterites and of mining residues such as mine tailings as well as metal recycling from waste (secondary mining). Metals being leached have to be recovered from acidic polymetallic solutions (mine and process waters) which is possible via biosorption or biomineralisation.

  16. Semantische Merkmale als Mittel der Textkonstitution

    Directory of Open Access Journals (Sweden)

    Stojan Bračič

    2008-12-01

    Full Text Available Im folgenden Beitrag sollen semantische Relationen unter die Lupe genommen werden, die im text dazu beitragen, dass einzelne Textkomponenten miteinander verknüpft werden. Dabei geht es hauptsächlich um Relationen, die nicht satzthematisch sind - diese sind nämlich als textuelle Koreferenzketten ausreichend untersucht worden (vgl. u.a. Bračič/Fix/Greule 2007 - sondern um jene Relationen, die als Prädikationen einzelner textgrammatischer Einheiten (Sätze vorkommen und ebenfalls gewisse geordnete Strukturierungen aufweisen.

  17. 基于在线学习和ADRC的发电机励磁与汽门系统ANN逆鲁棒控制方法%An online learning and active disturbance rejection control-based ANN-inversion robust control scheme of excitation and valve system for turbogenerator

    Institute of Scientific and Technical Information of China (English)

    徐庆宏; 黄家才; 李宏胜

    2012-01-01

    为提高汽轮发电机组励磁与汽门系统机端电压和功角的控制性能,提出了基于在线学习和自抗扰控制( ADRC)的神经网络逆鲁棒控制方法.首先,将神经网络逆(ANN)与被控励磁汽门系统组成的复合伪线性系统等效为含有扰动的线性系统;然后,基于ADRC,设计了用于在线估计复合伪线性系统状态和扰动的ESO,解决了神经网络逆在线学习时训练样本获取的难题,并在设计的伪控制量中对扰动进行补偿,基于线性系统理论证明了ESO的收敛性并针对励磁子系统和汽门子系统与神经网络逆系统组成的伪线性复合系统分别设计整数阶PID控制器和分数阶PID控制器以实现闭环控制;同时,在离线训练的基础上设计了基于在线梯度方法的神经网络逆在线学习算法,利用李雅普诺夫稳定性理论证明了神经网络逆在线学习的收敛性.最后,以典型的两区域四机系统为例进行数值仿真,与传统的AVR/PSS和基于离线训练的神经网络逆控制方法的比较结果表明所提方法明显提升了电力系统的暂态性能.%To improve the performance of the terminal voltage and power angle of the turbogenerator, an online learning and active disturbance rejection control (ADRC) based ANN-inversion (ANNI) robust control scheme was proposed. Firstly, the composite pseudo linear system, which is composed of the ANNI system and the controlled excitation and valve system, is equivalent to a linear system with disturbance. Then, an ESO was designed based on the ADRC method to estimate the states and the disturbance of the composite pseudo linear system online, in order to resolve the difficulty of online acquisition of training samples for the online learning of ANN inversion, and the pseudo control input with disturbance compensation was designed for the composite pseudo-linear system. Furthermore, the convergence of the ESO was proved by the linear system theory and an integral

  18. Dynamic imaging of the nasal cavity and the paranasal sinuses with polarized {sup 3}helium MRI; Dynamische Bildgebung der Nasenhaupthoehle und der Nasennebenhoehlen im MR mittels polarisiertem {sup 3}Helium

    Energy Technology Data Exchange (ETDEWEB)

    Hanke, A.; Gast, K.; Viallon, M.; Thelen, M.; Kauczor, H.U. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Radiologie; Markstaller, K. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Radiologie; Klinik fuer Anaesthesiologie, Univ. Mainz (Germany); Eberle, B. [Klinik fuer Anaesthesiologie, Univ. Mainz (Germany)

    2001-12-01

    left frontal sinus and 7.8 for the right side. (orig.) [German] Ziel: Im Rahmen dieser Studie sollte untersucht werden, ob die Inhalation von polarisiertem {sup 3}Helium und Bildgebung mittels MRT zu einer Anreicherung des Edelgases in der Nasenhaupthoehle und den Nasennebenhoehlen fuehrt. Ziel war es, durch die {sup 3}Helium-MRT eine Darstellung der Nasenhaupthoehle und der Nasennebenhoehlen zu ermoeglichen und Verteilungsstoerungen der Ventilation der Nasennebenhoehlen zu beurteilen. Probanden und Methoden: Untersucht wurden drei Probanden. {sup 3}Helium-Gas wurde durch optisches Pumpen auf einen Polarisationsgrad von 40 - 50% polarisiert. Ueber ein Glasroehrchen wurden 300 ml 100% {sup 3}Helium in die linke Nasenoeffnung bei verschlossener kontralateraler Nasenoeffnung und anschliessendem zweimaligen Valsalva Manoever appliziert. Durch die Verwendung einer im Rahmen der Lungenforschung erprobten computerunterstuetzten Applikationseinheit konnte ein vorwaehlbares Gasvolumen bei korrekter Abgabe des {sup 3}Heliums waehrend der Inspiration gewaehrleistet werden. Die Aufnahmen wurden an einem 1,5-T-MRT-System angefertigt. Die Messungen erfolgten mit einer ultraschnellen zweidimensionalen FLASH-Sequenz (TR = 2 ms, TE = 0,7 ms, FA < 2, Matrix 75 x 128, FOV = 500 mm) mit einer zeitlichen Aufloesung von 130 ms. Ergebnisse: Der linke Sinus maxillaris zeigt sich nach Gabe des {sup 3}He-Gases signalintensiver als der rechte. Die mittlere Signalintensitaet war mit 526{+-}86 links groesser als rechts (336{+-}102). Der Sinus frontalis und der Sinus ethmoidalis links und rechts zeigten nur eine Aufnahme des {sup 3}Helium-Gases nach zweimaligem Valsalva-Manoever. Durch die niedrige Signalintensitaet der Ethmoidal- und Frontalzellen kamen diese nur flau zur Darstellung. Das Signal/Rauschverhaeltnis betrug fuer den Sinus maxillaris links 14,1, rechts 8,9, den Sinus ethmoidalis links 6,3, rechts 5,8 und den Sinus frontalis links 6,6 und rechts 7,8. (orig.)

  19. A differentiated approach to the diagnosis of pulmonary embolism and deep venous thrombosis using multi-slice CT; Abklaerung von Lungenembolie und venoeser Thromboembolie mittels Mehrschicht-Spiral CT

    Energy Technology Data Exchange (ETDEWEB)

    Wildberger, J.E.; Mahnken, A.H.; Stargardt, A.; Haage, P.; Guenther, R.W. [Klinik fuer Radiologische Diagnostik (Germany); Sinha, A.M. [Medizinische Klinik 1, Universitaetsklinikum der RWTH Aachen (Germany); Schaller, S. [Siemens Medical Solutions, Computertomographie, Forchheim (Germany)

    2002-03-01

    ] Zielsetzung: Entwicklung eines diagnostischen Algorithmus fuer Mehrschicht-Spiral CT (MSCT) Untersuchungen bei klinisch vermuteter Lungenembolie (LE) mittels CT-Angiographie (CTA) und indirekter CT-Phlebographie (CTP). Material und Methode: Bei 161 konsekutiven Patienten mit klinischem Verdacht einer LE wurde nach intravenoeser Applikation von 120 ml Kontrastmittel eine duennschichtige CTA durchgefuehrt (SOMATOM Volume Zoom; Siemens, Forchheim; 120 kV, 100 mAs, Kollimation: 4 x 1 mm). Eine indirekte CTP (120 kV, 170 mAs, Kollimation: 4 x 5 mm) wurde in den Faellen angeschlossen, in denen eine LE bestaetigt werden konnte. Bei negativer CTA wurde diese nur bei den Patienten durchgefuehrt, bei denen klinische Zeichen bzw. vorausgegangene Untersuchungen eine tiefe Beinvenenthrombose (TVT) wahrscheinlich machten oder dies zur weiteren Therapieplanung und Ausdehnungsbestimmung erforderlich war. Beginnend am Beckenkamm wurde die CTP drei Minuten nach KM-Applikation in der Kniekehle beendet. Ergebnisse der CTP konnten bei 73 Extremitaeten mit dopplersonographischen, phlebographischen oder autoptischen Ergebnissen verglichen werden. Die Untersuchungsbereiche wurden bei allen Patienten aufgezeichnet und resultierende effektive Strahlendosen fuer beide Geschlechter getrennt berechnet. Ergebnisse: Bei 62 Patienten konnte der Verdacht einer Lungenembolie in der CTA bestaetigt werden. 47 dieser Patienten hatten eine ursaechliche TVT. Bei 47/99 Patienten ohne LE-Nachweis wurde eine zusaetzliche CTP durchgefuehrt. Hierbei wurde die Diagnose einer TVT aus vorauslich bei 2 von 39 Patienten (5,1%) wurde eine okkulte TVT ohne Nachweis einer LE festgestellt. Bei den Vergleichsuntersuchungen lag die Sensitivitaet fuer den Nachweis einer TVT bei 94,3% bei einer Spezifitaet von 92,1%. Nach ICRP 60 wurden kumulative effektive Strahlendosen fuer die Thorax-CT von 3,3 mSv fuer maennliche und 4,2 mSv fuer weibliche Patienten berechnet, fuer die CTP ergaben sich 9,3 mSv. Schlussfolgerungen: Das

  20. Prediction of the pharmacological effect of octreotide in acromegaly by means of {sup 111}In-pentetreotide scintigraphy and calculation of a pituitary uptake index; Praediktion der pharmakologischen Wirkung von Octreotid bei Akromegalie mittels {sup 111}In-Pentetreotid-Szintigraphie und Berechnung eines hypophysaeren Uptake-Index

    Energy Technology Data Exchange (ETDEWEB)

    Goerges, R. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Nuklearmedizin; Cordes, U. [Arbeitsgemeinschaft Niedergelassener Endokrinologen, Mainz/Darmstadt (Germany); Engelbach, M. [Mainz Univ. (Germany). III. Medizinische Klinik und Poliklinik; Bartelt, K.M. [Arbeitsgemeinschaft Niedergelassener Endokrinologen, Mainz/Darmstadt (Germany); Haberern, G. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Nuklearmedizin; Hey, O. [Mainz Univ. (Germany). Neurochirurgische Klinik und Poliklinik; Beyer, J. [Mainz Univ. (Germany). III. Medizinische Klinik und Poliklinik; Bockisch, A. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Nuklearmedizin

    1997-06-01

    Aim: The aim of our prospective study was to optimize the determination of the pituitary somatostatin receptor status by means of 111-In-pentetreotide scintigraphy and to compare it intraindividually with the pharmacological effect of octreotide in active acromegaly. Methods: In n=22 patients with growth hormone (GH) secreting pituitary adenoma, 111-In-penetreotide scintigraphy was performed, and the specific radionuclide accumulation in the pituitary area (evaluation visually as well as semiquantitatively by means of ROI technique and calculation of various uptake indices) was correlated with the acute drop of GH after administration of 100 {mu}g octreotide s.c. (octreotide acute test). Results: The uptake index we propose (cts/pixel-ratio circular pituitary ROI: Irregular cerebrum ROI after background correction in the sagittal SPECT slice with maximum pituitary uptake 24 h p.i.) correlates best with the pharmacological effect (acute decrease of GH levels) of octreotide; its upper normal limit amounts of 3.5. Conclusion: As often the normal pituitary gland can be visualized scintigraphically, the purely visual differentiation between a normal and pathological receptor status sometimes is equivocal. A pituitary uptake index, calculated by means of a standardized ROI technique, facilitates this discrimination and so contributes to select possible responders for a treatment with octreotide. (orig.) [Deutsch] Ziel: Ziel unserer prospektiven Studie war die optimierte Bestimmung des hypophysaeren Somatostatin-Rezeptorstatus in der 111-In-Pentetreotid-Szintigraphie und der intraindividuelle Vergleich mit dem pharmakologischen Effekt von Octreotid bei florider Akromegalie. Methoden: Bei n=22 Patienten mit Wachstumshormon-(GH)-sezernierendem Hypophysenadenom wurde eine 111-In-Pentetreotid-Szintigraphie durchgefuehrt und die spezifische Nuklidakkumulation in der Hypophysenregion (Auswertung sowohl visuell als auch semiquantitativ mittels ROI-Technik und Berechnung

  1. Engineering geological and hydrogeological invstigations for storage of medium and low-activity nuclear waste at Cernavoda, Romania. Soil stabilisation using the CONSOLID system; Ingenieurgeologische und hydrogeologische Untersuchungen zur Lagerung mittel- und schwachradioaktiver Abfaelle in Cernavoda Rumaenien. Baugrundstabilisierung mit dem CONSOLID-System

    Energy Technology Data Exchange (ETDEWEB)

    Giurgea, V.; Merkler, G.P.; Hoetzl, H.; Hannich, D. [Karlsruhe Univ. (T.H.) (Germany). Lehrstuhl fuer Angewandte Geologie

    1998-12-31

    In Cernavoda/Romania investigations and planning from a low and middle radioactive waste disposal site have been carried out. A multitude of hydrogeological, geological, engineering geological criteria`s and constructional security measures were examined with respect to the strict regulations for such a waste site. This studies and measures are shortly analyzed and discussed in this paper. In accordance with the selection criteria for such a hazardous waste site, several laboratory and `in situ` tests, soil-mechanic studies, numerical modeling and foundation tests for soil stabilization with the CONSOLID-System are presented. (orig.) [Deutsch] Zur Einhaltung der strengen Vorgaben, die bei einem Deponiestandort fuer mittel- und schwachradioaktive Abfaelle gestellt werden, sind in Cernavoda/Rumaenien eine Vielzahl von hydrogeologischen und ingenieurgeologischen Untersuchungen sowie bautechnischen Sicherungsmassnahmen vorgesehen, die im Rahmen dieser Publikation kurz analysiert und diskutiert werden. Im Zusammenhang mit den geologischen und hydrogeologischen Auswahlkriterien des Standortes werden eine Reihe von Labor- und `in situ` Untersuchungen, Modellrechnungen sowie Baugrundstabilisierungsmassnahmen mit dem CONSOLID-System vorgestellt. (orig.)

  2. Super- and Transcritical Fluid Expansions for Next-Generation Energy Conversion Systems

    NARCIS (Netherlands)

    Harinck, J.

    2010-01-01

    The next generation of thermodynamic power cycles offers great potential as the conceptual basis for sustainable energy converters. Examples are the supercritical and superheated Organic Rankine cycle, the transcritical condensation cycle, the supercritical Brayton cycle, the Organic Stirling cycle

  3. Super- and Transcritical Fluid Expansions for Next-Generation Energy Conversion Systems

    NARCIS (Netherlands)

    Harinck, J.

    2010-01-01

    The next generation of thermodynamic power cycles offers great potential as the conceptual basis for sustainable energy converters. Examples are the supercritical and superheated Organic Rankine cycle, the transcritical condensation cycle, the supercritical Brayton cycle, the Organic Stirling cycle

  4. Combined rankine and vapor compression cycles

    Science.gov (United States)

    Radcliff, Thomas D.; Biederman, Bruce P.; Brasz, Joost J.

    2005-04-19

    An organic rankine cycle system is combined with a vapor compression cycle system with the turbine generator of the organic rankine cycle generating the power necessary to operate the motor of the refrigerant compressor. The vapor compression cycle is applied with its evaporator cooling the inlet air into a gas turbine, and the organic rankine cycle is applied to receive heat from a gas turbine exhaust to heat its boiler within one embodiment, a common condenser is used for the organic rankine cycle and the vapor compression cycle, with a common refrigerant, R-245a being circulated within both systems. In another embodiment, the turbine driven generator has a common shaft connected to the compressor to thereby eliminate the need for a separate motor to drive the compressor. In another embodiment, an organic rankine cycle system is applied to an internal combustion engine to cool the fluids thereof, and the turbo charged air is cooled first by the organic rankine cycle system and then by an air conditioner prior to passing into the intake of the engine.

  5. Investigations on avoidance of hot cracks during laser welding of austenitic Cr-Ni steels and nickel-based alloys using temperature field tailoring. Final report; Untersuchungen zur Vermeidung von Heissrissen beim Laserstrahlschweissen von austenitischen Cr-Ni-Staehlen und Nickelbasislegierungen mittels Temperaturfeld-Tailoring. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-08-08

    . Zweitens wird bei rotationssymmetrischen Bauteilen, die mittels einer Axial-Rundnaht zu verschweissen sind, mit einem relativ einfachen Temperaturfeld, das durch Erwaermung des innen liegenden Fuegepartners vor und waehrend des Schweissens aufgebaut wird, ein Spannungsfeld erzeugt, das die Bildung von Heissrissen verhindert. Schliesslich konnte drittens ein heissrissfreies Laserstrahlschweissen des Stahls 1.4305 und der Nickelbasislegierung Udimet 720 bereits ohne den Einsatz zusaetzlicher Temperaturfelder erreicht werden. Die Grenzen der Einsetzbarkeit des Verfahrens bei Cr-Ni-Staehlen werden dann erreicht, wenn Quer-Heissrisse oder parallel zur Blechoberflaeche liegende Heissrisse entstehen. Die zur Vermeidung dieser Risse noetigen Druckspannungen in den Richtungen parallel zur Schweissnaht bzw. senkrecht zur Blechoberflaeche koennen mittels induktiver Erwaermung von der Blechoberseite aus nicht in der erforderlichen Groesse erzeugt werden. Ebenso stoesst das Verfahren an seine Grenzen, wenn Wiederaufschmelzungsrisse auftreten, was beim hier verwendeten Stahl 1.4435 der Fall war. Die Spannungen, die zur Verhinderung einer Rissoeffnung an den Korngrenzen der Waermeeinflusszone erforderlich waeren, konnten durch Temperaturfeld-Tailoring nicht erreicht werden. Die Moeglichkeit des heissrissfreien Schweissens des Stahls 1.4305 auch ohne Temperaturfeld-Tailoring ergibt sich hauptsaechlich aus dem primaer ferritischen Erstarrungsmodus des Stahls in der vorliegenden Legierungszusammensetzung. Ein industrieller Einsatz des Laserstrahlschweissens fuer diesen oft als nicht schweissbar klassifizierten Stahl erscheint moeglich, wenn bei der Legierungszusammensetzung auf niedrige Anteile der Austenitbildner Nickel, Kohlenstoff und Stickstoff Wert gelegt wird und damit eine stabil primaer ferritische Erstarrung erreicht wird. Fuer diesen Fall kommt es nicht zur Schwefelanreicherung an den Korngrenzen, wodurch die Bildung niedrigschmelzender Phasen und damit die Heissrissentstehung

  6. Investigations on avoidance of hot cracks during laser welding of austenitic Cr-Ni steels and nickel-based alloys using temperature field tailoring. Final report; Untersuchungen zur Vermeidung von Heissrissen beim Laserstrahlschweissen von austenitischen Cr-Ni-Staehlen und Nickelbasislegierungen mittels Temperaturfeld-Tailoring. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-08-08

    . Zweitens wird bei rotationssymmetrischen Bauteilen, die mittels einer Axial-Rundnaht zu verschweissen sind, mit einem relativ einfachen Temperaturfeld, das durch Erwaermung des innen liegenden Fuegepartners vor und waehrend des Schweissens aufgebaut wird, ein Spannungsfeld erzeugt, das die Bildung von Heissrissen verhindert. Schliesslich konnte drittens ein heissrissfreies Laserstrahlschweissen des Stahls 1.4305 und der Nickelbasislegierung Udimet 720 bereits ohne den Einsatz zusaetzlicher Temperaturfelder erreicht werden. Die Grenzen der Einsetzbarkeit des Verfahrens bei Cr-Ni-Staehlen werden dann erreicht, wenn Quer-Heissrisse oder parallel zur Blechoberflaeche liegende Heissrisse entstehen. Die zur Vermeidung dieser Risse noetigen Druckspannungen in den Richtungen parallel zur Schweissnaht bzw. senkrecht zur Blechoberflaeche koennen mittels induktiver Erwaermung von der Blechoberseite aus nicht in der erforderlichen Groesse erzeugt werden. Ebenso stoesst das Verfahren an seine Grenzen, wenn Wiederaufschmelzungsrisse auftreten, was beim hier verwendeten Stahl 1.4435 der Fall war. Die Spannungen, die zur Verhinderung einer Rissoeffnung an den Korngrenzen der Waermeeinflusszone erforderlich waeren, konnten durch Temperaturfeld-Tailoring nicht erreicht werden. Die Moeglichkeit des heissrissfreien Schweissens des Stahls 1.4305 auch ohne Temperaturfeld-Tailoring ergibt sich hauptsaechlich aus dem primaer ferritischen Erstarrungsmodus des Stahls in der vorliegenden Legierungszusammensetzung. Ein industrieller Einsatz des Laserstrahlschweissens fuer diesen oft als nicht schweissbar klassifizierten Stahl erscheint moeglich, wenn bei der Legierungszusammensetzung auf niedrige Anteile der Austenitbildner Nickel, Kohlenstoff und Stickstoff Wert gelegt wird und damit eine stabil primaer ferritische Erstarrung erreicht wird. Fuer diesen Fall kommt es nicht zur Schwefelanreicherung an den Korngrenzen, wodurch die Bildung niedrigschmelzender Phasen und damit die Heissrissentstehung

  7. Das Gesprächsführungspraktikum im 2. Studienjahr des Modellstudiengangs HannibaL: Eine Evaluation mittels Selbsteinschätzungen der Studierenden [The communication skills course for second year medical students at Hannover Medical School: An evaluation study based on students' self-assessments

    Directory of Open Access Journals (Sweden)

    von Lengerke, Thomas

    2011-11-01

    . Regarding methods, the deployed simulated patients (2-4 per 10-student-course group in 3 of the 7 course sessions, respectively were rated the most helpful. The present evaluation calls for both further development of the doctor-patient communication curriculum at the MHH and joint activities across medical schools, which are discussed at the end of the paper. [german] Im MHH-Modellstudiengang HannibaL werden Gesprächsführungskompetenzen für Anamneseerhebung und Diagnosemitteilung durch eine Objective Structured Clinical Examination (OSCE geprüft, die Teil der dem Ersten Abschnitt der Ärztlichen Prüfung äquivalenten Prüfungen sind. Das vorbereitende Gesprächsführungspraktikum im 2. Studienjahr wurde 2009/10 evaluiert.Mittels lernzielspezifischer Fragebogen wurden der Lernbedarf erhoben, Vorher-Nachher-Vergleiche der selbsteingeschätzten Kompetenzen durchgeführt und zentrale Lehrmethoden bewertet (5-Punkt-Likertskalen, „5“=hohe Ausprägung. Zu T0 (Beginn des Praktikums nahmen 267 Studierende teil (Teilnahmerate: 93,7%, von denen 180 den T1-Fragebogen beim letzten Praktikumstermin ausfüllten (67,4%. Es wurden Varianzanalysen mit Messwiederholungsfaktor und T-Tests für verbundene Stichproben durchgeführt. Die höchsten Lernbedarfe zeigten sich bei den „to show how“-Items zu Anamneseerhebung und Diagnosemitteilung (M=4,4. Die T1-T0-Vergleiche zeigten die größten Verbesserungen bei den anamnesespezifischen Items („to know how“: Mittelwertsdifferenz=+1,7, „to show how“:+1,8, p<.0001 wie bei allen Tests und beim „to know how“-Item zur Diagnosemitteilung (+1,6, gefolgt von der Umsetzung einer Diagnosemitteilung (+1,4, partizipativer Entscheidungsfindung (+1,2, der Einschätzung eigener Stärken/Schwächen (+1,0 und dem sicheren Zugehen auf neue Patienten (+0,7. Studierende mit T0-Werten von „1“ oder „2“ auf den jeweiligen Skalen verbesserten sich über alle Items im Mittel um 2,2 Punkte, solche mit „3“ um 1,1, und mit „4“ oder

  8. 3D-Erfassung und Objektrekonstruktion mittels Streifenprojektion

    OpenAIRE

    Gühring, Jens

    2002-01-01

    Die dreidimensionale Digitalisierung von Objekten mit Hilfe von optischen Verfahren hat in den vergangenen Jahren große Bedeutung gewonnen. Infolge der intensiven Forschung ist weltweit eine ganze Reihe von Systemen entwickelt worden, welche in so unterschiedlichen Bereichen wie industrieller Qualitätskontrolelle, Reverse Engineering, virtueller Realität und Medizin eingesetzt werden. Fortschritte in der Sensortechnik und der Verarbeitung der Messdaten haben die Erfassung nahezu beliebig komp...

  9. Untersuchungen zur Implementierung von Bildverarbeitungsalgorithmen mittels pulsgekoppelter neuronaler Netze

    OpenAIRE

    Mayr, Christian

    2014-01-01

    This thesis deals with the study of image processing algorithms which can be implemented by pulse-coupled neural nets. The inspiration for this choice is taken from biological image processing, which achieves with little computational effort in highly parallel processes image analysis tasks such as object recognition, image segmentation, velocity and distance estimation, etc. Conventional, serially implemented algorithms either cannot realize those tasks at all or will expend significantly mo...

  10. System identification with belief calculus; Systemidentifikation mittels Glaubenskalkuel

    Energy Technology Data Exchange (ETDEWEB)

    Duerrbaum, A.; Sommer, H. [Kassel Univ. (Germany). Fachgebiet Mess- und Regelungstechnik; Scherm, W. [Kassel Univ. (Germany). Inst. fuer Produktionstechnik und Logistik

    2008-07-01

    Belief theory provides a very powerful tool for system identification. In this paper the principal method is presented and compared with probability-theory based identification methods. The new method allows to transfer all user requests into optimisable parameters and makes a priori assumptions superfluous. The efficiency of the method is demonstrated in a practical application: the design of a systems which forecasts the damage of drill-bits. (orig.)

  11. Erfassung der Hämolyse mittels optischer Reflexionsspektroskopie

    OpenAIRE

    Neudel, Frank

    2002-01-01

    The mechanical blood damage (hemolysis) is a critical fact of medical blood assisting devices. In order to minimize the physiological stress of the patients, the flow rate must be adapted in terms of hemolysis. In this dissertation a new method for a continuous detection of hemolysis is presented. Compared to common techniques, containing withdrawal blood samples, plasma separation, chemical treatment and spectroscopic evaluation, the continuous evaluation of hemolysis reduces time and the ne...

  12. Hörrehabilitation mittels Cochlea Implantat bei Waardenburg Syndrom

    OpenAIRE

    Friese, N; Braun, K; Fehr, S.; Biskup, S.; Tropitzsch, A

    2016-01-01

    Einleitung: Das Waardenburg Syndrom ist ein überwiegend autosomal dominant vererbtes Krankheitsbild, das sich durch eine uni- oder bilaterale sensorineurale Schwerhörigkeit auszeichnet und bis zu 5 % der Fälle angeborener Schwerhörigkeit ausmacht. Die Gene, die beim Waardenburg Syndrom eine Rolle spielen, sind PAX3 (Typ I und III), MITF und SNAI2 (Typ II), SOX10 (Typ II und IV) sowie EDN3 und EDNRB (Typ IV). Über die funktionellen Ergebnisse nach Cochlea Implantation ist bisher noch wenig be...

  13. Nachweis von Natural Attenuation mittels Isotopenuntersuchungen an einem ehemaligen Kokereistandort

    Science.gov (United States)

    Nagel, Aglaia; Strauss, Harald; Stephan, Manuel; Achten, Christine

    2011-12-01

    Natural attenuation of mono- (BTEX) and polycyclic aromatic hydrocarbons (PAHs) was studied in groundwater at a former gas plant site over a distance of about 500 m. The contamination source was located within a 4-6 m thick succession of interbedded silt and sand ( K f =1,4ṡ10-7 m/s) at a depth of about 5-6 m below the surface. Groundwater flow times between source and the receiving surface waters were determined on the order of a few hundred years. The main contaminants were found to be benzene and naphthalene with concentrations up to 200,000 and 8,500 μg/l, respectively. Over the past 9 years, concentrations within the contaminant plume have decreased and degradation of benzene was proven by compound specific carbon isotope analyses. In addition, sulphur isotope studies revealed that sulphate reduction has played a significant role. This was supported by ambient sulphate concentrations of 300-1,800 μg/l at the site that are sufficient to sustain a long-term perspective for this process. In agreement with these physico-chemical conditions, no transfer of BTEX or PAHs from the plume into the nearby river has been observed.

  14. Treatment of malignant biliary occlusion by means of transhepatic percutaneous biliary drainage with insertion of metal stents - results of an 8-year follow-up and analysis of the prognostic parameters; Behandlung der malignen Gallenwegsstenose mittels perkutaner transhepatischer Metallendoprothesenimplantation: 8 Jahres-Ergebnisse und Analyse prognostischer Faktoren

    Energy Technology Data Exchange (ETDEWEB)

    Alfke, H.; Alfke, B.; Froelich, J.J.; Klose, K.J.; Wagner, H.J. [Klinik fuer Strahlendiagnostik Philipps Univ. Marburg (Germany)

    2003-08-01

    praediktive Faktoren fuer Ueberleben und Offenheitsraten zu detektieren. Methode: In einer retrolektiven Analyse wurden 130 Patienten evaluiert. Nachsorgedaten wurden anhand der Krankenakten und eines Telephoninterviews erhoben. Verfahrensassoziierte Daten waren prospektiv in einer Datenbank erhoben worden. Univariate und multivariate Vergleiche der Ueberlebens- und Offenheitsraten wurden mittels Kaplan-Meier-Analyse mit Log-Rank-Test fuer verschiedene Tumorentitaeten durchgefuehrt. Praediktive Faktoren fuer das Ueberleben und die 30-Tages-Mortalitaet wurden durch eine schrittweise logistische Regression evaluiert. Ergebnisse: Ursachen fuer die maligne Gallenwegsobstruktion waren Cholangiokarzinome (n=50), Pankreaskarzinome (29), Lebermetastasen (27), Gallenblasenkarzinome (20) und andere (4). Die technische Erfolgsrate betrug 99%, die Komplikationsrate 27% und die 30-Tages-Mortalitaet 11%. Die primaere Stentoffenheitsrate (406 Tage, Median 207) unterschied sich nicht signifikant fuer die verschiedenen Tumorentitaeten. Die Ueberlebensrate war fuer Patienten mit Cholangiokarzinomen in der univariaten Analyse signifikant besser (p=0,03 Log-Rank-Test). Die multiple Regressionsanalyse detektierte keine praediktiven Faktoren fuer das Ueberleben und die 30-Tages-Mortalitaet. Schlussfolgerungen: Die perkutane transhepatische Metallendoprothesenimplantation bietet den Patienten eine gute kurz- und langfristige palliative Therapie des Ikterus an. Obwohl die Ueberlebenszeit fuer Patienten mit Cholangiokarzinomen signifikant laenger ist, fehlen klare praediktive Faktoren fuer ein laengeres Ueberleben und eine erhoehte 30-Tages-Mortalitaet. (orig.)

  15. Comparison of left and right ventricular ejection and filling parameters by fast cine MR imaging in breath-hold technique: clinical study of 42 patients with cardiomyopathy and coronary heart disease; Vergleich links- und rechtsventrikulaerer Auswurf- und Fuellungsparameter des Herzens mittels Cine MRT in Atemanhaltetechnik: klinische Studie an 42 Patienten mit Kardiomyopathie und koronarer Herzerkrankung

    Energy Technology Data Exchange (ETDEWEB)

    Rominger, M.B.; Bachmann, G.F.; Geuer, M.; Puzik, M.; Rau, W.S. [Giessen Univ. (Germany). Diagnostische Radiologie; Ricken, W.W. [Kerckhoff-Klinik GmbH, Bad Nauheim (Germany). Abt. Kardiologie

    1999-06-01

    Purpose: Quantification of left and right ventricular filling and ejection of localized and diffuse heart diseases with fast cine MR imaging in breath-hold technique. Methods: 42 patients (14 idiopathic dilated cardiomyopathies (DCM), 13 hypertrophic cardiomyopathies (HCM) and 15 coronary artery diseases (CAD)) and 10 healthy volunteers were examined. Time-volume-curves of three left ventricular and one right ventricular slices were evaluated and peak ejection and filling rates (PER, PFR end-diastolic volume (EDV)/s) time to PER and PFR (TPER, TPFR ms) and time of end-systole (TSYS in % RR-intervall) were calculated. Results: There were significant regional and left-/right-sided differences of the filling and ejection of both ventricles within and between the different groups. In DCM the left ventricular PFR was reduced (DCM 3.1 EDV/s; volunteers 4.9 EDV/s) and Z-SYS prolonged (DCM 50.1%; volunteers 35.4%). In CAD there were localized decreased filling rates in comparison to the normal volunteer group (left ventricle: basal: 2.9 and 6.3 EDV/s, apical: 4.4 and 6.3 EDV/s; right ventricle: 3.6 and 5.7 EDV/s). HCM typically showed an isovolumetric lengthening of the endsystole. Conclusions: Cardiac MR imaging in breath-hold technique is suitable for measuring contraction and relaxation disturbances of localized and diffuse heart diseases by means of ejection and filling volume indices. (orig.) [Deutsch] Ziel: Quantifizierung der links- und rechtsventrikulaeren Fuellung und des Auswurfs bei umschriebenen und diffusen Herzerkrankungen mittels schneller Cine MR Bildgebung in Atemanhaltetechnik. Methoden: Untersucht wurden 42 Patienten (14 dilatative Kardiomyopathien (DCM), 13 hypertrophe obstruktive Kardiomyopathien (HCM) und 15 koronare Herzerkrankungen (KHK)) und 10 Probanden. Von drei linksventrikulaeren und einer rechtsventrikulaeren Einzelschicht wurden Zeit-Volumen-Kurven erstellt, aus denen die maximale Auswurf- und Fuellrate (MAR) (MFR eddiastolisches Volumen (EDV

  16. Sensitivity analysis of molecular design problem for the development of novel working fluids for power cycles

    DEFF Research Database (Denmark)

    Frutiger, Jerome; Abildskov, Jens; Sin, Gürkan

    identify the target properties of the CAMD problem for working fluids. In this study the CAMD problem for the development of novel working fluids for organic Rankine cycles (ORC) is formulated mathematically. It integrates both a system model for the ORC and property models including the Peng...... will be applied in a case study of an Organic Rankine Cycle (ORC) with a low-temperature heat source. The heat source is a hot water stream from waste heat of a chemical site. Giving this pre-exquisite the method allows to identify the most favorable working fluid along with the corresponding optimal process...... conditions in order to get the highest possible power output. The study presents a new approach for the identification of target properties of CAMD problems based on sensitivity analysis and shows its application for the development of novel working fluids of organic Rankine cycles for low temperature heat...

  17. A Comparison of Organic and Steam Rankine Cycle Power Systems for Waste Heat Recovery on Large Ships

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Meroni, Andrea; Haglind, Fredrik

    2017-01-01

    This paper presents a comparison of the conventional dual pressure steam Rankine cycle process and the organic Rankine cycle process for marine engine waste heat recovery. The comparison was based on a container vessel, and results are presented for a high-sulfur (3 wt %) and low-sulfur (0.5 wt...... %) fuel case. The processes were compared based on their off-design performance for diesel engine loads in the range between 25% and 100%. The fluids considered in the organic Rankine cycle process were MM(hexamethyldisiloxane), toluene, n-pentane, i-pentane and c-pentane. The results of the comparison...... indicate that the net power output of the steam Rankine cycle process is higher at high engine loads, while the performance of the organic Rankine cycle units is higher at lower loads. Preliminary turbine design considerations suggest that higher turbine efficiencies can be obtained for the ORC unit...

  18. Property Uncertainty Analysis and Methods for Optimal Working Fluids of Thermodynamic Cycles

    DEFF Research Database (Denmark)

    Frutiger, Jerome

    There is an increasing interest in recovering industrial waste heat at low tempera-tures (70-250◦C). Thermodynamic cycles, such as heat pumps or organic Rankine cycles, can recover this heat and transfer it to other process streams or convert it into electricity. The working fluid, circulating...... in the context of an industrial organic Rankine cycle, used for the recovery of waste heat from an engine of a marine container ship. The study illustrates that the model structure is vital for the uncertainties of equations of state and suggests that uncertainty becomes a criterion (along with e.g. goodness......-of-fit or ease of use) for the selection of an equation of state for a specific application. Furthermore, two studies on the identification of suitable working fluids for thermodynamic cycles are presented. The first one selects and assesses working fluid candidates for an organic Rankine cycle system to recover...

  19. Investigation of the local fracture toughness and the elastic-plastic fracture behavior of NiAl and tungsten by means of micro-cantilever tests; Untersuchung der lokalen Bruchzaehigkeit und des elastisch-plastischen Bruchverhaltens von NiAl und Wolfram mittels Mikrobiegebalkenversuchen

    Energy Technology Data Exchange (ETDEWEB)

    Ast, Johannes

    2016-07-01

    . This is linked to the thermally activated dislocation mobility which is more constrained in those samples. Investigations on plastically predeformed samples were performed in order to study the influence of the dislocation density on the fracture behavior. It was found that the fracture toughness was again not affected but that the predeformed samples failed at an earlier stage at lower J-integrals. This is due to the lower mobility of the dislocations emitted from the crack tip in consequence of the high amount of strain hardening and the higher flow stress in those samples. Experiments in ultrafine-grained tungsten revealed a fracture behavior which was more brittle than expected. A single grain at the crack front with its crystallographic orientation being prone to cleavage failure can decisively influence the fracture behavior at the micro scale. [German] Das Ziel dieser Arbeit war es, ein verbessertes Verstaendnis fuer die Groessenabhaengigkeit der Bruchzaehigkeit zu gewinnen. Hierfuer wurden mittels fokussierter Ionenstrahlen gekerbte Mikrobiegebalken in verschiedenen Groessen vom Submikrometerbereich bis hin zu einigen 10 μm in B2-NiAl und Wolfram praepariert. Diese beiden Materialien besitzen charakteristische Sproed-Duktil-Uebergange, die oberhalb der Raumtemperatur liegen. Dies erlaubte es, Bruchvorgaenge, welche von begrenzter plastischer Verformung um die Rissspitze begleitet werden, auf der Mikroskala zu untersuchen. Neue Methoden zur Beschreibung und Bestimmung des lokalen elastisch-plastischen Bruchverhaltens bzw. der Bruchzaehigkeit wurden hierfuer erarbeitet. Im Speziellen wurde das J-Integral-Konzept zur Ermittlung von Rissfortschritt ueber Steifigkeitsmessungen auf die Mikroskala uebertragen. Dies ermoeglichte eine praezise Analyse des fuer die Bruchzaehigkeit charakteristischen Uebergangs von Rissabstumpfung zu stabilem Rissfortschritt. Die Versuche an einkristallinem NiAl fuer die beiden untersuchten Risssysteme der harten und weichen Orientierung

  20. Applications guide for waste heat recovery

    Science.gov (United States)

    Moynihan, P. I.

    1983-01-01

    The state-of-the-art of commercially available organic Rankine cycle (ORC) hardware from a literature search and industry survey is assessed. Engineering criteria for applying ORC technology are established, and a set of nomograms to enable the rapid sizing of the equipment is presented. A comparison of an ORC system with conventional heat recovery techniques can be made with a nomogram developed for a recuperative heat exchanger. A graphical technique for evaluating the economic aspects of an ORC system and conventional heat recovery method is discussed: also included is a description of anticipated future trends in organic Rankine cycle R&D.

  1. Shaft torsional oscillation interactions between turbo-generators in parallel in series compensated transmission systems

    Energy Technology Data Exchange (ETDEWEB)

    Mello, F.P. de

    1994-12-31

    Several investigators have raised the possibility of interaction between shaft systems of parallel units, particularly among identical units. The question addressed in this paper is the significance of this interaction between shaft systems of units coupled through the electrical system. A time domain model of two parallels units connected to an infinite bus trough a series compensated transmission is used to evaluate the phenomena. The same model is used to extract pertinent frequency response functions by Fourier processing of pulse response tests from which a frequency response analysis is performed to lend additional insight into the phenomena. (author) 8 refs., 13 figs., 3 tabs.

  2. Simulation of Plain Bearings in Turbo-Generators Using the Stand ISO7902

    Directory of Open Access Journals (Sweden)

    Alejandra Elena García Toll

    2011-02-01

    Full Text Available The study of plain bearings is fundamental in guaranteeing the full running and maintenance of machines. Due to the fluctuations in working conditions, the simulation of plain bearing in turbines and generators has become increasingly necessary. The procedure used to obtain data is based on ISO Standards 7902:1998 which involves the calculation of the load capacity of plain bearings under hydrodynamic lubricant conditions. This method can be used to determine if the plain bearing under load and working conditions will be able to form and maintain a film of lubricant which is important to separate completely the shaft and bearing sliding surfaces in order to prevent friction between these two. Also, with this method it is possible to determine the ideal working conditions and limiting factors in the functioning of plain bearing. Some of these factors are: relative bearing clearance, shaft velocity, lubricant viscosity, diameter and width of bearing, average peak-to-valley height of sliding surfaces and nominal radial. Additionally, a calculation sample is presented

  3. Passivation controller design for turbo-generators based on generalised Hamiltonian system theory

    NARCIS (Netherlands)

    Cao, M.; Shen, T.L.; Song, Y.H.

    2002-01-01

    A method of pre-feedback to formulate the generalised forced Hamiltonian system model for speed governor control systems is proposed. Furthermore, passivation controllers are designed based on the scheme of Hamiltonian structure for single machne infinite bus and multimachine power systems. In parti

  4. Design of nonlinear adaptive steam valve controllers for a turbo-generator system

    Energy Technology Data Exchange (ETDEWEB)

    Bekiaris-Liberis, N.K.; Paraskevopoulos, P.N. [National Technical Univ. of Athens Zographou, Athens (Greece); Boglou, A.K. [Technology Education Inst. of Kavala Agios Loukas, Kavala (Greece); Arvanitis, K.G.; Pasgianos, G.D. [Agricultural Univ. of Athens, Athens (Greece)

    2008-07-01

    This paper reported on a study that investigated the control of power systems consisting of interconnected networks of transmission lines linking generators and loads. Improving both small and large perturbation stability and dynamic performance is important because power systems have become less stable in the past 15 years due to the use of controllers that have been designed on the basis of linearized synchronous generators and turbine models. The high nonlinear nature of power system models and the resulting disturbances render conventional linear controller design techniques obsolete for use in power systems control. Power system engineers are becoming aware of the role of turbine steam valves in improving the dynamic stability of power systems and damping low frequency oscillations. Advanced nonlinear control strategies are needed since the conventional steam valve control theory cannot guarantee transient stability in cases where operational conditions and parameters vary considerably. A design approach to a nonlinear adaptive control system with unknown parameters was developed and applied to the turbine main steam valve control of a power system. A fourth order machine model was used along with an adaptive backstepping method to construct the Lyapunov function in order to obtain a nonlinear adaptive controller to solve the turbine fast valving nonlinear control problem. The newly designed nonlinear adaptive controller can make the resulting adaptive system asymptotically stable. The proposed controller is accompanied by a dynamic estimator of parameters and includes nonlinear damping terms, which guarantee input-output stability even without the use of the adaptive law. Simulation results showed that the proposed nonlinear adaptive controller performs better than other turbine main steam valve control techniques. It can face large parametric uncertainty and results in a closed-loop system that is able to face large and smaller disturbances, providing a quite fast and smooth response, in both regulatory control and set-point tacking cases. 23 refs., 10 figs.

  5. Nonlinear Disturbance Attenuation Controller for Turbo-Generators in Power Systems via Recursive Design

    NARCIS (Netherlands)

    Cao, M.; Shen, T.L.; Song, Y.H.; Mei, S.W.

    2002-01-01

    The paper proposes a nonlinear robust controller for steam governor control in power systems. Based on dissipation theory, an innovative recursive design method is presented to construct the storage function of single machine infinite bus (SMIB) and multi-machine power systems. Furthermore, the nonl

  6. ELECTROMAGNETIC VIBRATION DISTURBING FORCES AT THE ECCENTRICITY OF ROTOR OF TURBOGENERATOR

    Directory of Open Access Journals (Sweden)

    Yu.M. Vaskovskyi

    2016-09-01

    Full Text Available Electromagnetic vibration disturbing forces in different variants of the rotor displacement from an axis of the stator bore is carried out. Investigation for ТG type ТGV-200-2 by finite element method in COMSOL Multiphysics is carried out. The field mathematical model of static and dynamic eccentricity is described. The amplitude vibration disturbing forces are greatest, when a static eccentricity direction coincides with an axis of the stator winding phase is shown. The diagnostic features static and dynamic eccentricities are formulated. The most value of forces in the point with minimal air gap is shown. The diagnostic features static and dynamic eccentricities and the method of diagnostic eccentricity are formulated. Diagnostic feature of static eccentricity is to change the amplitude Maxwell stress tensor is established. The dynamic eccentricity diagnostic features are appearance in the spectrum of vibration disturbing forces rotating and multiple harmonics.

  7. Experimental results for hydrocarbon refrigerant vaporization inside brazed plate heat exchangers at high pressure

    DEFF Research Database (Denmark)

    Desideri, Adriano; Ommen, Torben Schmidt; Wronski, Jorrit;

    2016-01-01

    In recent years the interest in small capacity organic Rankine cycle (ORC) power systems for harvesting low qualitywaste thermal energy from industrial processes has been steadily growing. Micro ORC systems are normally equippedwith brazed plate heat exchangers which allows for efficient heat tra...

  8. Real-Gas Effects in ORC Turbine Flow Simulations: Influence of Thermodynamic Models on Flow Fields and Performance Parameters

    NARCIS (Netherlands)

    Colonna, P.; Rebay, S.; Harinck, J.; Guardone, A.

    2006-01-01

    The analysis and design of turbomachinery is usually performed by means of fluid dynamic computations employing ideal gas laws. This can lead to inaccurate redictions for Organic Rankine Cycle (ORC) turbines, which operate partly in the nonideal thermodynamic region. The objective of this work is to

  9. Fluid dynamic design and analysis of a highly loaded Centrifugal rotor for mini orc power systems

    NARCIS (Netherlands)

    Vitale, S.; Pini, M.; Ghidoni, A.; Colonna di Paliano, P.

    2015-01-01

    Organic Rankine Cycle (ORC) power systems are a well-established technology for the conversion of thermal energy sources in the small-to-medium power range. In the last few years, efforts have been devoted to the development of mini ORC (mORC) power systems (5- 30 kWe) for waste heat recovery from t

  10. Modelling, experimentation and simulation of a reversible HP/ORC unit to get a Positive Energy Building

    DEFF Research Database (Denmark)

    Dumont, Olivier; Carmo, Carolina; Quoilin, Sylvain

    2015-01-01

    This paper presents an innovative building comprising a heat pump connected to a solar roof and a geothermal heat exchanger. This unit is able to invert its cycle and operate as an Organic Rankine Cycle (ORC). The solar roof is producing large amount of heat throughout the year. This allows...

  11. Small-scale CHP Plant based on a 35 kWel Hermetic Four Cylinder Stirling Engine for Biomass Fuels- Development, Technology and Operating Experiences

    DEFF Research Database (Denmark)

    Obernberger, I.; Carlsen, Henrik; Biedermann, F.

    2003-01-01

    should normally be operated on a heat-controlled basis in order to achieve a high overall efficiency and should run for more than 5,000 annual full load operating hours to ensure economical operation. Two of the technologies examined are very promising and innovative: the Organic Rankine Cycle (ORC...

  12. Unsteady rans simulation of the off-design operation of a high expansion ratio ORC radial turbine

    NARCIS (Netherlands)

    Rinaldi, E.; Pecnik, R.; Colonna di Paliano, P.

    2015-01-01

    The design of Organic Rankine cycle (ORC) turbines is a challenging task due to the complex thermodynamic behavior of the working fluid, the typical high expansion ratio which leads to a highly supersonic flow, the flow unsteadiness, and the continuous shift of operation between on- and off-design

  13. Fluid dynamic design and analysis of a highly loaded Centrifugal rotor for mini orc power systems

    NARCIS (Netherlands)

    Vitale, S.; Pini, M.; Ghidoni, A.; Colonna di Paliano, P.

    2015-01-01

    Organic Rankine Cycle (ORC) power systems are a well-established technology for the conversion of thermal energy sources in the small-to-medium power range. In the last few years, efforts have been devoted to the development of mini ORC (mORC) power systems (5- 30 kWe) for waste heat recovery from

  14. Siloxanes: A new class of candidate Bethe-Zel’dovich-Thompson fluids

    NARCIS (Netherlands)

    Colonna, P.; Guardone, A.; Nannan, N.R.

    2007-01-01

    This paper presents a new class of Bethe-Zel’dovich-Thompson fluids, which are expected to exhibit nonclassical gasdynamic behavior in the single-phase vapor region. These are the linear and cyclic siloxanes, light silicon oils currently employed as working fluids in organic Rankine cycle turbines.

  15. Assesment of Emerging Renewable Energy-based Cogeneration Systems for nZEB Residential Buildings

    DEFF Research Database (Denmark)

    Carmo, Carolina; Dumont, Olivier; Nielsen, Mads Pagh

    2016-01-01

    thermal reversible heat pump /organic Rankine cycle (HP/ORC) and cogeneration solar Thermoelectric generators (TEG). This paper aims to give an overview of the state-of-the-art developments, discuss the fundamental and technical challenges facing commercial adoption and prospects of these technologies...

  16. Real-Gas Effects in ORC Turbine Flow Simulations: Influence of Thermodynamic Models on Flow Fields and Performance Parameters

    NARCIS (Netherlands)

    Colonna, P.; Rebay, S.; Harinck, J.; Guardone, A.

    2006-01-01

    The analysis and design of turbomachinery is usually performed by means of fluid dynamic computations employing ideal gas laws. This can lead to inaccurate redictions for Organic Rankine Cycle (ORC) turbines, which operate partly in the nonideal thermodynamic region. The objective of this work is to

  17. A comparison of advanced heat recovery power cycles in a combined cycle for large ships

    DEFF Research Database (Denmark)

    Larsen, Ulrik; Sigthorsson, Oskar; Haglind, Fredrik

    2014-01-01

    Strong motivation exists within the marine sector to reduce fuel expenses and to comply with ever stricter emission regulations. Heat recovery can address both of these issues. The ORC (organic Rankine cycle), the Kalina cycle and the steam Rankine cycle have received the majority of the focus in...

  18. A Comparison of Organic and Steam Rankine Cycle Power Systems for Waste Heat Recovery on Large Ships

    Directory of Open Access Journals (Sweden)

    Jesper Graa Andreasen

    2017-04-01

    Full Text Available This paper presents a comparison of the conventional dual pressure steam Rankine cycle process and the organic Rankine cycle process for marine engine waste heat recovery. The comparison was based on a container vessel, and results are presented for a high-sulfur (3 wt % and low-sulfur (0.5 wt % fuel case. The processes were compared based on their off-design performance for diesel engine loads in the range between 25% and 100%. The fluids considered in the organic Rankine cycle process were MM(hexamethyldisiloxane, toluene, n-pentane, i-pentane and c-pentane. The results of the comparison indicate that the net power output of the steam Rankine cycle process is higher at high engine loads, while the performance of the organic Rankine cycle units is higher at lower loads. Preliminary turbine design considerations suggest that higher turbine efficiencies can be obtained for the ORC unit turbines compared to the steam turbines. When the efficiency of the c-pentane turbine was allowed to be 10% points larger than the steam turbine efficiency, the organic Rankine cycle unit reaches higher net power outputs than the steam Rankine cycle unit at all engine loads for the low-sulfur fuel case. The net power production from the waste heat recovery units is generally higher for the low-sulfur fuel case. The steam Rankine cycle unit produces 18% more power at design compared to the high-sulfur fuel case, while the organic Rankine cycle unit using MM produces 33% more power.

  19. Decrease in the damage of powerful turbogenerator stator caused by vibration in the end zones (analysis, hypotheses, experiment

    Directory of Open Access Journals (Sweden)

    Yu.A. Shumilov

    2014-03-01

    Full Text Available The analysis of the turbogenerators’ TВВ-1000-2Y3 failure has shown that the most vulnerable link in the stator is such of their elements as tightening prisms, the teeth of the end packet core, lead-out and connecting buses of the stator winding. The basic reason for the destruction of the elements mentioned is metal fatigue caused by excessive vibration under the influence of variable axial forces of electromagnetic origin. Preventing the destruction of the structural elements may be achieved by vibration monitoring and diagnostics.

  20. 汽轮发电机失磁过程分析%Analysis of dynamic processes for turbo-generator

    Institute of Scientific and Technical Information of China (English)

    马波涛; 姚缨英

    2008-01-01

    针对目前汽轮发电机失磁异步运行性能的不断提高,对汽轮发电机失磁过程进行了仿真分析.从系统角度建立了模拟汽轮发电机失磁故障的数学模型,并利用Matlab/Simulink对失磁全过程进行了仿真分析,并利用该模型对汽轮发电机的失磁故障进行了仿真计算.仿真结果与实测结果的对比说明了仿真模型的正确性,对电机设计和电网运行具有一定的有参考价值.

  1. Engineering failure assessment methods applied to pressurized components; Bruchmechanische Bewertung druckfuehrender Komponenten mittels ingenieurmaessiger Bewertungsverfahren

    Energy Technology Data Exchange (ETDEWEB)

    Zerbst, U.; Beeck, F.; Scheider, I.; Brocks, W. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Werkstofforschung

    1998-11-01

    Under the roof of SINTAP (Structural Integrity Assessment Procedures for European Industry), a European BRITE-EURAM project, a study is being carried out into the possibility of establishing on the basis of existing models a standard European flaw assessment method. The R6 Routine and the ETM are important, existing examples in this context. The paper presents the two methods, explaining their advantages and shortcomes as well as common features. Their applicability is shown by experiments with two pressure vessels subject to internal pressure and flawed by a surface crack or a through-wall crack, respectively. Both the R6 Routine and the ETM results have been compared with results of component tests carried out in the 1980s at TWI and are found to yield acceptable conservative, i.e. sufficiently safe, lifetime predictions, as they do not give lifetime assessments which unduly underestimate the effects of flaws under operational loads. (orig./CB) [Deutsch] Gegenwaertig wird im Rahmen von SINTAP (Structural Integrity Assessment Procedures for European Industries), einem europaeischen BRITE-EURAM-Projekt geprueft, inwieweit auf der Grundlage vorhandener Modelle eine einheitliche europaeische Fehlerbewertungsmethode erstellt werden kann. Eine zentrale Stellung kommt dabei Verfahren wie der R6-Routine und dem ETM zu. In der vorliegenden Arbeit wurden beide Methoden vorgestellt, wobei ihre Vor- und Nachteile, aber auch ihre Gemeinsamkeiten herausgearbeitet wurden. Die Anwendung wurde an zwei innendruckbelasteten Behaeltern mit Oberflaechen- bzw. wanddurchdringendem Riss demonstriert. Sowohl R6-Routine als auch ETM ergaben im Vergleich mit am TWI zu Beginn der 80er Jahre durchgefuehrten Bauteilexperimenten eine vertretbare konservative Vorhersage, d.h. eine nicht allzu grosse Unterschaetzung der ertragbaren Last der Bauteile. (orig.)

  2. Korrekturverfahren zur numerischen Lösung nichtlinearer Optimierungsprobleme mittels Methoden der parametrischen Sensitivitätsanalyse

    OpenAIRE

    Nikolayzik, Tim

    2012-01-01

    The nonlinear optimization has becoming of the key technologies of the field of applied mathematics. There are various numbers of applications in different fields of science, e.g. economics, medicine and engineering. Also industry is using mathematical algorithms for solving nonlinear optimization problems. Especially in the aerospace industry nonlinear optimization is frequently used for optimizing trajectories. The aim of this thesis is to extend an existing method for solving nonlinear opt...

  3. Uterine cervical cancer. Preoperative staging with magnetic resonance imaging; Zervixkarzinom. Praeoperatives Staging mittels Magnetresonanztomographie

    Energy Technology Data Exchange (ETDEWEB)

    Collettini, F.; Hamm, B. [Charite-Universitaetsmedizin Berlin, Campus Charite Mitte, Klinik fuer Radiologie, Berlin (Germany)

    2011-07-15

    The treatment of uterine cervical carcinoma is largely dependent on the tumor stage. Despite significant inaccuracies in the clinical examination, uterine cervical cancer remains the only gynecological form of cancer still largely staged according to clinical findings. Although imaging is still not included in the staging the recently published revised FIGO (Federation International de Gynecologie et d'Obstetrique) system encourages the use of modern cross-sectional imaging (magnetic resonance imaging MRI and computed tomography CT). Due to its high soft tissue contrast MRI allows excellent non-invasive assessment of the cervix with direct tumor delineation as well as assessment of the prognosis based on morphological factors. Studies in the literature report an accuracy of 93% for MRI in the preoperative assessment of tumor size and in the differentiation of operable from advanced cervical cancer. Therefore MRI is considered to be the optimal modality for diagnostic evaluation starting from FIGO stage IB1, for radiation therapy planning, and for exclusion of recurrence in follow-up. In this paper we give an overview of the role of magnetic resonance imaging in preoperative staging of uterine cervical cancer. (orig.) [German] Die Therapieplanung beim Zervixkarzinom ist weitgehend von der Stadieneinteilung nach FIGO (Federation International de Gynecologie et d'Obstetrique) abhaengig, die trotz erheblicher Ungenauigkeiten bei der klinischen Stadieneinteilung weiterhin aufgrund klinischer Untersuchungsbefunde erfolgt. Obwohl bildgebende Verfahren nach wie vor fuer die Stadieneinteilung nicht vorgesehen sind, wird im kuerzlich erschienen revidierten Stagingsystem der FIGO zum ersten Mal die Verwendung moderner Schnittbilddiagnostik (MRT und CT) befuerwortet. Die MRT ermoeglicht dank ihres hohen Weichteilkontrasts ein ausgezeichnetes nichtinvasives Staging des Zervixkarzinoms mit direkter Tumordarstellung sowie einer Prognoseabschaetzung anhand bildmorphologischer Faktoren. Nach Ergebnissen in der Literatur betraegt die Genauigkeit der MRT bei der praeoperativen Abschaetzung der Tumorgroesse sowie der Differenzierung operabler Zervixkarzinome von fortgeschrittenen Karzinomen 93%. Sie wird daher nicht nur als das Verfahren der Wahl zur diagnostischen Beurteilung ab FIGO-Stadium IB1 angesehen, sondern auch zur Strahlentherapieplanung sowie zum Rezidivausschluss im Rahmen der Nachsorge. In der folgenden Arbeit geben wir einen Ueberblick ueber die Rolle der MRT bei der praeoperativen Stadieneinteilung des Zervixkarzinoms. (orig.)

  4. Mittel- und osteuropäische Wohlfahrtsstaaten im Vergleich: Typen und Leistungsfähigkeit

    NARCIS (Netherlands)

    Keune, M.; Klenner, C.; Leiber, S.

    2009-01-01

    Die stufenweise Erweiterung der Europäischen Union in den letzten Jahren hat eine erneute Debatte um das Europäische Sozialmodell, die Zukunft der verschiedenen Wohlfahrtsstaatsmodelle und die Interaktionen zwischen diesen nationalen Modellen angestoßen (z.B. Hemerijck et al. 2006; Jepsen/ Serrano P

  5. Analyse hochwarmfester metallischer Legierungen mittels Metallografie,Rasterelektronenmikroskopie und energiedispersiver Röntgenanalyse

    OpenAIRE

    Hoven, H; Koizlik, K.; Schölgens, E.; Schubert, F.; Nickel, Hubertus

    1980-01-01

    Under operating conditions, refractory alloys outside the core of gas-cooled high temperature reactors are subject to corrosion processes. These corrosion phenomena and products have to be classified. For this reason, characterization procedures are necessary, which, in spite of fast and easy handling, yield exact and reproducable information. This paper describes the combined use of metallography, chromatic contrasting in a gas ion reaction chamber and secondary electron microscopy together...

  6. Energy-efficient cooling using absorption chilling; Energieeffizient kuehlen mittels Absorber

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, W.

    2009-07-01

    This article takes a look at a new hotel in Basel, Switzerland, whose 112 rooms are cooled in summer using a heat-driven absorption refrigeration system. The heat is provided by the city's district heating system. The IWB utility supports the environmental management efforts of the hotel chain by supplying heat during the summer at reduced rates. Figures on the system are quoted. The double facade of this 2-star hotel and its ceiling-integrated heating and cooling system are looked at and the roof-mounted cold generation system is described. The roof-mounted elements of the cooling system and the stipulations of the City of Basel regarding appearance and noise abatement are commented on.

  7. Analyse einer mit PbS-Nanopartikeln sensibilisierten Injektionssolarzelle mittels elektrochemischer und frequenzmodulierter Verfahren

    OpenAIRE

    Krüger, Susanne

    2012-01-01

    In the latter half of the 20th century the first active environmentalist movements such as Greenpeace and the International Energy Agency were born and initiated a gradual rethinking of environmental awareness. Against all expectations the sole agency under international law for climate protection policy, called the United Nations Framework Convention on Climate Change, was formed 20 years later. Today the awareness of sustained, regenerative and environmental policies permeates throughout al...

  8. OPTIDUST. Reduction of dust in biomass boilers using electrostatic filters; OPTIDUST. Staubreduzierung in Biomassekesseln mittels Elektrofilter

    Energy Technology Data Exchange (ETDEWEB)

    Gross, Bodo; Berhardt, Alexander [Institut fuer ZukunftsEnergieSysteme (IZES) gGmbH, Saarbruecken (Germany); Clemens, Wulf [OTS GmbH, Riegelsberg (Germany); Lezsovits, Fernec [Budapest Univ. of Technology and Economics (Hungary). Dept. of Energy Engineering

    2012-07-01

    The authors of the contribution under consideration report on an electrostatic dust collecting system for a biomass central heating system. The electrostatic dust collecting system consists of a separation system and a control unit. A compact construction shall be realized. The separation system shall be suitable especial for non-round geometries at consistently high separation performance in order to fulfil the specifications of the 1st Federal Nuisance Control Ordinance. The authors report on the development of a separation system for the woodchip burning vessel from BIOKOMPAKT Heiztechnik GmbH (Waldhausen, Austria). The separation system is fully implemented in the post-heating areas and can be operated within field tests. Additionally, a universally retrofittable module is developed and tested by means of a log wood boiler from HOVAL GmbH (Aschheim, Federal Republic of Germany) within a further field test.

  9. Investigation of layered semiconductors by photoelectrochemical microwave reflection; Untersuchung von Schichtgitterhalbleitern mittels photoelektrochemischer Mikrowellenreflexion

    Energy Technology Data Exchange (ETDEWEB)

    Moehl, T.

    2005-07-01

    In this thesis electrochemical and photoelectrochemical investigations on n-molybdenum disulfide and p-tungsten diselenide are presented. They have good preconditions to be used in thin film solar cells. So far the major drawback are the surface states induced by unsaturated bonds at the crystal edges which lower the efficiency of energy conversion. A major focus of this work was the investigation of the semiconductor/electrolyte interface. For the measurements mainly n-type MoS{sub 2} and some p-type WSe{sub 2} samples were used. As basic characterisation the back contact was tested. With AFM and XPS the surface was investigated. Hall and conductance measurements were performed for the electronic parameters and cyclic voltammetry and DEMS were carried out to test the electrochemical behaviour. The characteristics of these crystals under illumination were investigated using the combinatoric technique of simultaneous measurement of the photocurrent and the microwave reflection. By this method it is possible to detect the excess charge carriers that reach the external circuit (photocurrent) and the ones that remain in the semiconductor (microwave reflection). The measurement of the from the periodically illuminated crystal reflected microwave radiation provides the light induced change in photoconductance. This change in conductance is proportional to the number of excess charge carriers that remain in the semiconductor whereby their behaviour can be studied under different experimental conditions. The measurements were performed potential controlled in a three electrode setup with different electrolytes and different excitation wavelengths. By the variation of the electrolytes the border cases of inhibited and uninhibited charge transfer were approximated. Thereby conclusions on the charge transfer could be drawn. The behaviour of charge carriers in the bulk and in space charge region could be explored separately analysing different penetration depth of different wavelengths. To passivate the unsaturated bonds at the crystal edges, the surface was treated with different molecules (cysteine, EDTA and Tween 80) and the impact on corrosion, charge transfer and recombination investigated. Tween 80 showed an effective reduction of dark and photo corrosion in electrochemical inert electrolyte, whereas the photocurrent was enhanced in electrolyte with redox system. Similar results were obtained by the treatment with EDTA but to a smaller extent. If the surface was treated with cysteine the photocurrent was also enhanced in analogy to the results of the other adsorbed compounds. In electrochemical inert electrolyte along with the reduction of photo corrosion a quenching of excess charge carriers in the semiconductor was observed. Finally the sensitivity factor of the microwave reflection was calculated measuring at 875 nm illumination wavelength. This sensitivity factor could be used to calculate a charge transfer constant for holes under conditions of a moderate charge transfer. (Orig.)

  10. Verfestigung asymmetrischer Beziehungsstrukturen mittels Gewalt The Solidification of Asymetrical Structures of Relationships through Violence

    Directory of Open Access Journals (Sweden)

    Daniel Osterwalder

    2004-07-01

    Full Text Available Die Arbeit der Historikerin Claudia Töngi dreht sich um verschiedene Formen von Gewalt wie Tötungsdelikte, häusliche und sexuelle Gewalt. Auf der Basis einer umfangreichen Daten- und Quellensammlung aus dem Gerichtsarchiv des Schweizer Kantons Uri (die zudem im Anhang aufgeführt wird zeigt sie, wie sich im 19. Jahrhundert Frauen und Männer zur Anwendung von Gewalt stellten und wie sich Gewaltpraktiken und deren Wahrnehmung im besprochenen Zeitraum verändert haben. Einerseits bringt Claudia Töngi noch unpublizierte Archivakten vor dem Hintergrund sozialgeschichtlicher Fragestellungen zum Sprechen, andererseits ermöglicht sie interessierten Forscher/-innen, die vergleichend zu Gewalt und Delinquenz arbeiten, raschen Zugriff auf die urnerischen Daten. Die Untersuchung wurde als Projekt Nr. 15 im Rahmen des Nationalfondsprogramms „Gewalt im Alltag und organisierte Kriminalität“ (NFP 40; URL: http://www.nfp40.ch, 20.04.2004 durchgeführt.The work of the historian Claudia Töngi focuses on different forms of violence such as killing crimes and domestic and sexual violence. Based on a broad collection of data and primary documents from the court archive of the Swiss canton of Uri (which is provided in the appendix, she illustrates how women and men viewed the use of violence in the 19th century and how practices of violence and their perceptions were transformed in the time-period considered. On the one hand, Claudia Töngi brings the still unpublished archival documents against the backdrop of social-historical questions to light. On the other hand, she allows interested researchers who work comparatively on violence and delinquency quick access to data. The study was carried out as project number 15 within the framework of the National Fonds Program “Violence in Everyday Life and Organized Criminality" (NFP 40; http://www.nfp40.ch, 20.04.2004.

  11. Optimierung von Reflektoren in Straßenleuchten mittels Bézier-Raum-Deformation

    OpenAIRE

    App, Andreas

    2006-01-01

    Diese Arbeit beschreibt eine Methode zur Optimierung von Reflektorflächen, wie sie typischerweise bei der Straßenbeleuchtung Verwendung finden, im Hinblick auf eine vorgegebene Lichtverteilung, mit Hilfe der Bézier-Raum-Deformation.

  12. Institutionalisierung durch Imitation? Die Europäisierung des Parlamentarismus in Mittel- und Osteuropa / Aron Buzogany

    Index Scriptorium Estoniae

    Buzogany, Aron

    2015-01-01

    Artikli teemaks on parlamentarismi euroopastumine Kesk- ja Ida-Euroopa riikides (sh Eesti), püüdes leida vastus küsimusele, kuidas on rahvusriikide parlamendid suutnud institutsionaalselt euroopastumise väljakutsele vastata?

  13. Investigation of relativistic laser-plasmas using nuclear diagnostics; Untersuchung relativistischer Laserplasmen mittels nukleardiagnostischer Verfahren

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, Marc M.

    2011-01-19

    The present work explores with the development of a novel nuclear diagnostic method for the investigation of the electron dynamics in relativistic laser-plasma interactions. An additional aim of this work was the determination of the real laser peak intensity via the interaction of an intense laser short-pulse with a solid target. The nuclear diagnostics is based on a photo-neutron disintegration nuclear activation method. The main constituent of the nuclear diagnostic are novel pseudoalloic activation targets as a kind of calorimeter to measure the high-energy bremsstrahlung produced by relativistic electrons. The targets are composed of several stable isotopes with different ({gamma},xn)-reaction thresholds. The activated nuclides were identified via the characteristic gamma-ray decay spectrum by using high-resolution gamma spectroscopy after the laser irradiation. Via the gamma spectroscopy the ({gamma},xn)-reaction yields were determined. The high-energy bremsstrahlung spectrum has been deconvolved using a novel analysis method based on a modified Penfold-Leiss method. This facilitates the reconstruction of the spectrum of bremsstrahlung photons without any anticipated fit procedures. Furthermore, the characterization of the corresponding bremsstrahlung electrons in the interaction zone is accessible immediately. The consolidated findings about the properties of the relativistic electrons were used to determine the real peak intensity at the laser-plasma interaction zone. In the context of this work, experiments were performed at three different laser facilities. First Experiments were carried out at the 100 TW laser facility at Laboratoire pour l'Utilisation des Lasers Intense (LULI) in France and supplementary at the Vulcan laser facility at Rutherford Appleton Laboratory (RAL) in United Kingdom. The main part of the activation experiments were performed at the PHELIX laser facility (Petawatt High Energy Laser for heavy Ion EXperiments) at GSI-Helmholtzzentrum fuer Schwerionenforschung GmbH in Germany, which were the first nuclear activation experiments at this facility. The results obtained with the novel nuclear diagnostics method have lead to an advanced understanding of high-energy electrons produced in relativistic laser-plasma interactions. Particularly, the capability of the nuclear activation-based method to determine the real laser peak intensity at the relativistic laser-plasma interaction zone was demonstrated. (orig.)

  14. Quantifizierungen von Grundwassereintritten in städtische Abwassersysteme mittels stabiler Isotope

    Science.gov (United States)

    Penckwitt, Jan; van Geldern, Robert; Hagspiel, Burkard; Packebusch, Birgit; Mahr, Alexander; Burkhardt, Klaus; Barth, Johannes A. C.

    2016-09-01

    Infiltration of groundwater into sewer systems increases the costs for wastewater treatment plant operators. This study explores groundwater infiltration to urban sewer systems in the city of Nuremberg (Germany). Measurements of stable isotopes at the water works, storage tanks, groundwater, and the sewage network were carried out to define input end members for mass balance calculations. Only minor differences in oxygen stable isotopes (δ18OH2O) were found between most sewer and drinking water samples which ranged around (- 9.5 ± 0.1) ‰. One exception was water from a water works at Genderkingen that is situated about 80 km south of Nuremberg. Here, drinking water from bank filtrate of the Lech River had more negative δ18OH2O values of - 11.4 ‰. This difference of 1.5 ‰ revealed maximum possible groundwater contributions of 41 % by mass balance calculations. To obtain more accurate results, we suggest testing the use of deuterium-enriched water (D2O) added to the sewer system.

  15. Musikerbriefe als Spiegel überregionaler Kulturbeziehungen in Mittel - und Osteuropa

    Directory of Open Access Journals (Sweden)

    Loos Helmut

    2002-01-01

    Full Text Available (nemački Traditionell ist die Musikgeschichtsschreibung nicht nur in Deutschland, sondern auch im östlichen Europa sehr stark nationalen Kriterien verpflichtet, und Musik wird vor allem als Nationalkultur verstanden. Dem gegenüber stehen viele Verflechtungen von Musikern, die in vergangenen Jahrhunderten häufig an vielen Orten Europas anwesend und tätig waren. Diese Verbindungen sind immer wieder einmal thematisiert, aber nur ansatzweise systematisch erforscht worden. Die überregionale Korrespondenz der Musiker im mittleren und östlichen Europa macht nicht nur europäische Verflechtungen sichtbar, sie liefert auch authentische Einschätzungen der Erfahrungen, die an verschiedenen Orten gesammelt wurden. Insgesamt ist zu erwarten, daß Europa im Spiegel der Musikerbriefe als der zusammenhängende Kulturraum im Musikleben erscheint, als der er bis weit ins 20. Jahrhundert hinein existierte.

  16. FOCJ as a Means of Regional Cooperation (FOCJ als Mittel regionaler Kooperation)

    Science.gov (United States)

    2008-03-01

    Systemwettbewerb, in: Fiskalffi- deralismus in Europa, hrsg. von Alois Oberhauser, Berlin 1997, S. 9-60 Solow , Robert M., A Contribution to the Theory of...Investitionsbetrag in Kapital die Kapitafintensit&i der Diese Form der Darstellung der Produktionsfunktion geht zurick auf Solow (1956). Eine ausflhrliche Diskussion...Norbert, Finanzwissenschaft, 4. Aufl., Tiibingen 1998 Barro, Robert J. und Xavier Sala-i-Martin, Economic Growth, New York 1995 Bathelt, Harald und

  17. Environmentally friendly use of manure by means of fluidized-bed combustion. Umweltfreundliche Guelleverwendung mittels Wirbelbettfeuerung

    Energy Technology Data Exchange (ETDEWEB)

    Hoelter, H.; Igelbuescher, H.; Gresch, H.; Dewert, H.

    1988-01-28

    According to the invention, it is proposed to spray a fluidized-bed combustion plant, which is operated with coal, for example, and which releases NO{sub x} as well as SO{sub 2} and dust, with manure. These measures according to the invention achieve that: 1. The manure is burnt in an environmentally friendly way, as the fluidized bed, with the addition of lime and a subsequent cloth filter, which is precoated with hydrated lime and filter ash, separates the dry substances of the manure on the filter, which are released by combustion in the form of ash, without causing a smell. 2. It was found that the manure causes a reduction of NO{sub x} in the fluidized bed. (orig./RB).

  18. Process for cleaning flue gas by chemical absorption masses. Verfahren zum Reinigen von Rauchgas mittels Chemiesorptionsmassen

    Energy Technology Data Exchange (ETDEWEB)

    Hoelter, H.; Igelbuescher, H.; Gresch, H.; Dewert, H.

    1987-05-07

    The invention concerns a process for cleaning flue gas by means of chemical absorption masses (e.g. hydrated lime, CaCO/sub 3/), which are blown in behind the boiler space or behind an electrical precipitator stage after the boiler space into a dry chemical absorption section and are separated via a further subsequent filter as a mixture containing CaSO/sub 3/ and CaSO/sub 4/. The end product is usually CaSO/sub 3/ and a small proportion of CaSO/sub 4/. However, one wants to obtain CaSO/sub 4/ for further use. In order to make this possible, according to the invention, the separated mixture containing CaSO/sub 3/ and CaSO/sub 4/ is taken via a transport section to a combustion area in which there is an excess of air and in which the temperature is lower than 830/sup 0/C. The CaSO/sub 4/ formed is then removed, together with the ash and/or slag.

  19. Test der Speziellen Relativitätstheorie mittels Laserspektroskopie an relativistischen 7 Li +-Ionen am ESR

    OpenAIRE

    Botermann, Benjamin

    2012-01-01

    Die Invarianz physikalischer Gesetze unter Lorentztransformationen ist eines der fundamentalen Postulate der modernen Physik und alle Theorien der grundlegenden Wechselwirkungen sind in kovarianter Form formuliert. Obwohl die Spezielle Relativitätstheorie (SRT) in einer Vielzahl von Experimenten mit hoher Genauigkeit überprüft und bestätigt wurde, sind aufgrund der weitreichenden Bedeutung dieses Postulats weitere verbesserte Tests von grundsätzlichem Interesse. Darüber hinaus weisen moderne ...

  20. Modern neuroimaging of brain plasticity; Darstellung von Plastizitaet mittels moderner klinischer Neurobildgebung

    Energy Technology Data Exchange (ETDEWEB)

    Kasprian, G. [Medizinische Universitaet Wien, Abteilung fuer Neuroradiologie und Muskuloskelettale Radiologie, Universitaetsklinik fuer Radiodiagnostik, Wien (Austria); Seidel, S. [Medizinische Universitaet Wien, Universitaetsklinik fuer Neurologie, Wien (Austria)

    2010-02-15

    Modern neuroimaging methods offer new insights into the plasticity of the human brain. As the techniques of functional MRI and diffusion tensor imaging are increasingly being applied in a clinical setting, the examiner is now frequently confronted with the interpretation of imaging findings related to regenerative processes in response to lesions of the central and also of the peripheral nervous system. In this article individual results of modern neuroimaging studies are discussed in the context of structural and functional plasticity of the CNS. (orig.) [German] Moderne Bildgebungsmethoden ermoeglichen neue Einblicke in die Plastizitaet des menschlichen Gehirns. Da Techniken wie das funktionelle MRT und die Diffusions-Tensor-Bildgebung zusehends bei der klinisch-radiologischen Untersuchung an Bedeutung gewinnen, ist der Untersucher mit der Interpretation von Bildgebungsdaten konfrontiert, die regenerative Prozesse als Konsequenz von Laesionen des zentralen und peripheren Nervensystems darstellen. Im vorliegenden Artikel werden individuelle Ergebnisse moderner MR-Untersuchungstechniken im Kontext struktureller und funktioneller Plastizitaet diskutiert. (orig.)

  1. Bewertung von Fahrerassistenzsystemen mittels der Vehicle in the Loop-Simulation

    Science.gov (United States)

    Bock, Thomas

    Mit der Vehicle in the Loop-Simulation hat Audi eine Test- und Simulationsumgebung für Fahrerassistenzsysteme entwickelt, welche die Vorzüge eines realen Versuchsfahrzeugs mit der Sicherheit und Reproduzierbarkeit von Fahrsimulatoren kombiniert. Virtueller Fremdverkehr, Straßenbegrenzungen oder sonstige simulierte Gegenstände werden durch ein "Optical see through Head Mounted Display“ während der Fahrt realitätsnah und kontaktanalog für den Fahrer eingeblendet. Besonders bei der Erprobung aktiver Fahrerassistenzsysteme eröffnen sich durch das Konzept des virtuellen Fremdverkehrs im realen Versuchsfahrzeug neue Möglichkeiten.

  2. Herstellung und Charakterisierung mikrostrukturierter Beschichtungen mittels Ink-jet und Pad-printing

    OpenAIRE

    Danzebrink, Rolf

    2006-01-01

    Mikrooptische Systeme erhalten in unserer Zeit eine immer wichtigere Bedeutung. Es müssen dafür die bisherigen Herstellungsmethoden überdacht und nach neuen Prinzipien geforscht werden. Mikrolinsen werden in Detektoren, Glasfaserkupplungen oder auch in der Sensortechnik eingesetzt. In dieser Arbeit wird die prinzipielle Machbarkeit geprüft, Mikrolinsen mit Hilfe eines Tintenstrahl- und Tampondruck- Prozesses herzustellen, indem ein hybrid-organisch-anorganisches Sol auf einem Glassubstrat abg...

  3. Precise thin film synthesis by ion beam sputter deposition; Herstellung von Praezisionsschichten mittels Ionenstrahlsputtern

    Energy Technology Data Exchange (ETDEWEB)

    Gawlitza, P.; Braun, S.; Leson, A.; Lipfert, S. [Fraunhofer-Institut fuer Werkstoffphysik und Schichttechnologie (IWS), Dresden (Germany); Nestler, M. [Roth und Rau AG, Hohenstein-Ernstthal (Germany)

    2007-04-15

    Ion beam sputter deposition (IBSD) is a promising technique for the fabrication of high performance thin films because of the well defined and adjustable particle energies, which are rather high in comparison to other PVD techniques. Recent developments concerning long-term stability and lateral uniformity of the ion beam sources strengthen the position of the IBSD technique in the field of precise thin film synthesis. Furthermore, IBSD offers a more independent choice of relevant deposition parameters like particle energy and flux, process gas pressure and deposition rate. In this paper we present our currently installed large area IBSD facility 'IonSys 1600', which was developed by Fraunhofer IWS Dresden and Roth and Rau company (Hohenstein-Ernstthal). Substrate sizes of up to 200 mm (circular) or up to 500 mm length (rectangular) can be coated and multilayer stacks with up to six different materials are possible. Tailored 1- or 2- dimensional film thickness distribution with deviations of <0.1% can be fabricated by a relative linear motion of the substrate holder above an aperture. In order to demonstrate the advantages of the IBSD technique especially for sophisticated materials and films with high requirements concerning purity, chemical composition or growth structure, several examples of deposited multilayers for various applications are presented. (orig.)

  4. Nichtinvasive Magnetresonanz- Perfusionsmessung des Gehirns mittels Magnetischer Blutbolusmarkierung (Spin-Labeling)

    OpenAIRE

    Warmuth, Carsten

    2003-01-01

    Arterial spin labeling methods allow to determine quantitative tissue blood flow values noninvasively. Arterial blood is labelled by an inversion pulse and the distribution of this intrinsic tracer is measured using magnetic resonance imaging. Experiments using an extra corporal in-vitro porcine kidney in a MR compatible set-up were carried out to determine the accuracy of blood flow values calculated from arterial spin labeling measurements. In a study of 36 brain tumor patients, spin labeli...

  5. Untersuchungen zur Hydrodynamik in chromatographischen Säulen mittels Computertomographie und numerischer Strömungssimulation

    OpenAIRE

    Lottes, Florian

    2013-01-01

    In der vorliegenden Arbeit wurde die Trennleistung chromatographischer Säulen präparativen Maßstabs untersucht. Die Effizienz solcher Säulen, deren Einsatz heutzutage eine echte Alter-native zu bewährten Trennoperationen, wie etwa Extraktion oder Rektifikation darstellt, wird maßgeblich durch die Struktur des mit porösen Partikeln gepackten Bettes beeinflusst. Die Packungsstruktur bestimmt die Durchströmung und somit die Verteilung der flüssigen Phase innerhalb der Säule, welche sich im Ideal...

  6. Untersuchung zur Verbesserung des Vitamin-D-Stoffwechsels bei Altersheimbewohnern mittels einer Bestrahlung mit ultraviolettem Licht

    Directory of Open Access Journals (Sweden)

    Scharla SH

    2006-01-01

    Full Text Available Vitamin-D-Mangel ist ein bedeutender Risikofaktor für Knochenbrüche im Alter. Die vorliegende Untersuchung überprüfte die Wirkung einer künstlichen UV-Licht-Bestrahlung auf den Vitamin D-Status, die Parathormonkonzentration im Serum sowie den Knochenabbaumarker NTX im Urin (NTX = quervernetzte N-Telopeptide aus Kollagen Typ 1 bei älteren Frauen im Altersheim. Die UV-Licht-Bestrahlung wurde mit 3 verschiedenen kommerziellen Lampen durchgeführt, die nicht primär für medizinische Anwendungen vorgesehen waren. Es wurden insgesamt 18 Bestrahlungseinheiten über 6 Wochen durchgeführt, wobei die Bestrahlungsdosis jeweils 30 bis 40% der minimalen Erythemschwellendosis betrug. Die Bestrahlung wurde von den Probanden ohne Nebenwirkungen gut vertragen. Vor Beginn der Bestrahlung (im Spätwinter, Februar war der Vitamin-D-Versorgungsgrad der Altersheimbewohnerinnen sehr schlecht (25-Hydroxyvitamin D 25 nmol/l bei mehr als 80 % der Frauen, weiterhin war der Knochenabbaumarker NTX deutlich erhöht. Es kam unter Bestrahlung und auch in der Nachbeobachtungszeit zu keiner signifikanten Änderung der Serumkonzentration von 25-Hydroxyvitamin D und Parathormon, der Knochenabbaumarker NTX zeigte in einer Gruppe einen leichten Rückgang. Es zeigte sich weiterhin eine erwartete inverse Korrelation der Serumkonzentration von Parathormon mit 25-Hydroxyvitamin D (r = –0,19; p 0,03 und überraschend eine positive Korrelation zwischen Kalzium und Parathormon (r = 0,24; p 0,02, auf eine autonomisierte Parathormonsekretion bei einigen Frauen hinweisend. Parathormon war weiterhin positiv mit dem Knochenabbaumarker NTX korreliert (r = 0,21; p 0,026, dagegen gab es keine signifikante Korrelation zwischen 25-Hydroxyvitamin D und dem Knochenabbaumarker NTX (p = 0,83 und auch nicht zwischen 25-Hydroxyvitamin D und der alkalischen Phosphatase (r = –0,04, p = 0,648. Fazit: Das durchgeführte Bestrahlungsprotokoll konnte den Vitamin D-Status nicht signifikant verbessern. Zu beachten ist weiterhin die Autonomisierung der Parathormonsekretion bei einigen der älteren Frauen mit Vitamin-D-Mangel.

  7. Results of ultrasonic disintegration of sewage sludge in practice; Ergebnisse des Praxiseinsatzes der Schlammdesintegration mittels Ultraschall

    Energy Technology Data Exchange (ETDEWEB)

    Friedrich, E. [IWE-Ingenieurgesellschaft fuer Wasser und Entsorgung mbH, Radebeul (Germany); Friedrich, H. [Fraunhofer-Institut fuer Keramische Technologien und Sinterwerkstoffe (IKTS), Dresden (Germany); Hielscher, H. [Hielscher GmbH, Teltow (Germany)

    1999-07-01

    Using high-performance ultrasonic sludge disintegration in different stages of sewage and sludge treatment is found to be an innovative approach for reducing the accruing amounts of sewage sludge in terms of both mass and volume. By means of practical tests with sludge disintegration at sewage treatment plants, its effects are demonstrated. (orig.) [German] Der Einsatz einer Hochleistungs-Ultraschalltechnik zur Schlammdesintegration in verschiedenen Stufen der Abwasser- und Schlammbehandlung zeigt sich als innovativer Loesungsweg zur weitestgehenden massenmaessigen sowie volumenmaessigen Minimierung des Klaerschlammanfalles. An Hand von Einsatzerprobungen der Desintegration in der Klaeranlagenpraxis werden die Effekte der Desintegration vorgestellt. (orig.)

  8. Biologische Augmentation der Sehnenheilung mittels Wachstumsfaktoren nach induzierter Supraspinatussehnenruptur am Rattenmodell

    OpenAIRE

    Reichel, Thomas

    2015-01-01

    Es wurde in-vivo die Wirkung des Wachstumsfaktors G-CSF auf die Supraspinatussehnenheilung im Rattenmodell untersucht. Der Wachstumsfaktor wurde über ein neu entwickeltes Phospholipidgel über 20 Tage kontinuierlich im Bereich der Rekonstruktion freigesetzt. Der Defekt wurde nach dem in unserer Vorstudie entwickelten Modell der chronischen Supraspinatussehnendegeneration zuvor gesetzt. Eine signifikant bessere Zellularitätsvariation, eine bessere Kollagenverteilung sowie ein positiver Trend zu...

  9. Intestinal small bowel lymphomas - diagnosis and treatment; Primaer intestinale Lymphome - Diagnosestellung mittels CT und Therapie

    Energy Technology Data Exchange (ETDEWEB)

    Goessmann, H.; Reith, H.B. [Klinikum fuer Visceral-, Thorax und Gefaesschirurgie, Klinikum Konstanz (Germany); Goerlitz, T.; Beck, A. [Inst. fuer Roentgendiagnostik und Nuklearmedizin, Klinikum Konstanz (Germany)

    2006-07-01

    Primary intestinal lymphomas are most common in the stomach. The mucosa associated lymphatic tissue (MALT)-lymphoma which is closely associated with helicobacter pylori is very well known. In most cases, these malignancies are from B-cells origin. Another possible point of manifestation, although not well known, is the small bowel. Both tumors have enormous capabilities to enlarge in the abdominal cave. This is responding to their often asymptomatic manifestation. The symptoms, if they occur, are widespread and unspecific. Ileus, diarrhae, abdominal pain or bleeding will be observed, in rare cases also perforation or gastrointestinal or cutaneous fistulas. Diagnostic imaging often demonstrates a tumour of massive size by then, which is echopoor in the abdominal ultrasound. Our report concerns two cases of small intestine lymphomas, which were diagnosed by CT-scanning and treated in our clinic in only a short period of time. The first case was a low malignant jejunal lymphoma which was almost asymptomatic, whereas the second case had an ileus, due to compression of the intestine because of a high malignant lymphoma of the ileocecal region. (orig.)

  10. Untersuchung des Verunreinigungsprofils von Aminosäuren aus fermentativer Herstellung mittels Kapillarelektrophorese

    OpenAIRE

    Novatchev, Nikolai

    2002-01-01

    Gegenstand der vorliegenden Arbeit war die Untersuchungen von Verunreinigungsprofilen von Aminosäuren aus biotechnologischer Herstellung. Dazu sollten die Aminosäuren Arg, His, Ile, Lys, Phe, Pro, Ser und Trp von verschiedenen Herstellern und aus unterschiedlichen Batches genauer unter die Lupe genommen werden. Mit der im Europäischen Arzneibuch beschriebenen dünnschichtchromatographischen Methode (DC-Methode) für „mit Ninhydrin nachweisbare Substanzen“ können ausschließlich Fremdaminosäuren ...

  11. Quality assessment with the AGIR software results and experience; Qualitaetsmanagement mittels AGIR: Ergebnisse und Erfahrungen

    Energy Technology Data Exchange (ETDEWEB)

    Rauch, D.; Kotter, E.; Kurtz, C.; Schaefer, O.; Ehritt-Braun, C.; Burger, D.; Schaper, J.; Uhrmeister, P. [Freiburg Univ. (Germany). Radiologische Universitaetsklinik, Abt. fuer Roentgendiagnostik

    2001-02-01

    Purpose: To evaluate whether a new software from the working group for interventional radiology (AGIR) is an appropriate tool for quality assurance in interventional radiology, and presentation of results acquired within the quality improvement process in 1999. Patients and methods: AGIR-defined parameters such as patient data, risk profile, given interventions as well as complications were registered by a recently developed software. Based on monthly data analyses, possible complications were identified and discussed in morbidity and mortality conferences. Results: 1014 interventions were performed in our institution in 1999. According to criteria established by AGIR, the complication rate was 2.7%. In addition and according to SCVIR criteria, complications were distinguished quantitatively in five classes and semiquantitatively in minor and major groups. The result was a minor complication rate of 1.8%, and a major rate of 0.9%. There were no cases of death associated with the intervention. Further strategies were developed in order to reduce the complication rate. Conclusion: Extensive quality assurance methods can be integrated in daily routine work. These methods lead to an intensive transparency of treatment results, and allow the implementation of continuous quality improvements. The development of the software is a first step in establishing a nation-wide quality assurance system. Nevertheless, modification and additional definition of the AGIR predefined parameters are required, for example, to avoid unnecessary procedures. (orig.) [German] Ziel: Evaluierung einer neuen Software der arbeitsgemeinschaft interventionelle radiologie (AGIR) hinsichtlich der Eignung als Instrument zur Qualitaetssicherung in der interventionellen Radiologie sowie Praesentation der Ergebnisse innerhalb des Qualitaetsprozesses aus dem Jahre 1999. Patienten und Methoden: Mit Hilfe einer neuen Software wurden AGIR definierte Parameter wie Patientendaten, Risikoprofil, die jeweilige Intervention sowie Komplikationen registriert. Basierend auf monatlichen Datenanalysen wurden eventuelle Komplikationen erfasst. Diese wurden in den Morbiditaets- und Mortalitaetskonferenzen diskutiert. Ergebnisse: 1999 wurden an unserem Institut 1014 Interventionen durchgefuehrt. Die Komplikationsrate lag nach den von der AGIR festgelegten Kriterien bei 2,7%. Zusaetzlich wurden die Komplikationen nach den Kriterien des SCVIR (society of cardiovascular and interventional radiology) qualitativ in 5 Klassen und semiqualitativ in Minor und Major unterteilt. Es resultierte eine Minor-Komplikationsrate von 1,8% und eine Major-Rate von 0,9%. Verfahrensassoziierte Todesfaelle traten nicht auf. Um die Komplikationsrate zu reduzieren, wurden weitere Strategien entwickelt. Schlussfolgerung: Umfassende Qualitaetssicherungsmassnahmen lassen sich in den Routineablauf integrieren. Die Massnahmen fuehren zu einer hohen Transparenz der Behandlungsergebnisse sowie der Moeglichkeit, kontinuierliche Qualitaetsverbesserungen vorzunehmen. Die Entwicklung der Software ist ein erster Schritt in der Etablierung eines flaechendeckenden Qualitaetssicherungssystems. Dennoch bedarf es einer Modifikation und ergaenzenden Definition der von der AGIR definierten Parameter, nicht zuletzt um unnoetige Prozeduren zu unterbinden. (orig.)

  12. Light out-coupling from LEDs by means of metal nanoparticles; Lichtauskopplung aus LEDs mittels Metallnanoteilchen

    Energy Technology Data Exchange (ETDEWEB)

    Goehler, Tino

    2010-12-17

    The external quantum efficiency of light-emitting diodes (LEDs) based on Al- GaAs/InGaAlP is limited by total internal reflection because of the high refractive index (typically between 3 and 4) of the semiconductor. Metal nanoparticles (MNP) deposited on the surface of the LED can be used as dipole scatterers in order to enhance the emission of the LED. In this thesis, first, single gold nanoparticles of various sizes deposited on such an LED were investigated. A clear enhancement is detected as long as the dipole plasmon resonance of the particle is at a shorter wavelength than the LED emission. If the plasmon resonance coincides with the LED emission or is at a larger wavelength, the enhancement turns into suppression. Numerical simulations indicate that this latter effect is mainly caused by the particle quadrupole resonance producing extra absorption. Arrays of MNPs can be produced by a special mask technique called ''Fischer pattern nanolithography'' and manipulated in shape and size by additional steps. Originally, the MNPs produced by this technique are triangular in shape and turn out to suppress the LED emission. After transformation of the particles to spheres, a clear enhancement was detected. Light that would otherwise remain trapped inside the substrate is coupled out by resonant plasmonic scattering. Investigations on analogous structures on a transparent high-index material (GaP) indicate a stronger coupling between the particles than expected on the basis of literature data. (orig.)

  13. Institutionalisierung durch Imitation? Die Europäisierung des Parlamentarismus in Mittel- und Osteuropa / Aron Buzogany

    Index Scriptorium Estoniae

    Buzogany, Aron

    2015-01-01

    Artikli teemaks on parlamentarismi euroopastumine Kesk- ja Ida-Euroopa riikides (sh Eesti), püüdes leida vastus küsimusele, kuidas on rahvusriikide parlamendid suutnud institutsionaalselt euroopastumise väljakutsele vastata?

  14. Technologies for waste heat recovery in off-shore applications

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Haglind, Fredrik; Kandepu, Rambabu

    2013-01-01

    technological and economic challenges that need to be overcome. However, onshore established technologies such as the steam Rankine cycle, the air bottoming cycle and the organic Rankine cycle can be tailored to recover the exhaust heat off-shore. In the present paper, benefits and challenges of these three...... different technologies are presented, considering the Draugen platform in the North Sea as a base case. The Turboden 65-HRS unit is considered as representative of the organic Rankine cycle technology. Air bottoming cycles are analyzed and optimal design pressure ratios are selected. We also study a one...... pressure level steam Rankine cycle employing the once-through heat recovery steam generator without bypass stack. We compare the three technologies considering the combined cycle thermal efficiency, the weight, the net present value, the profitability index and payback time. Both incomes related to CO2...

  15. Design and modeling of an advanced marine machinery system including waste heat recovery and removal of sulphur oxides

    DEFF Research Database (Denmark)

    Frimann Nielsen, Rasmus; Haglind, Fredrik; Larsen, Ulrik

    2013-01-01

    In order to reduce the formation of acid rain and its harmful effects, stricter legislations on emissions of sulphur oxides from ships applies as of 2015 in emission control areas and globally in 2020 by the international maritime organization (IMO). Consequently, prices on low sulphur fuels...... of the machinery system. The wet sulphuric acid process has shown to be an effective way of removing sulphur oxides from flue gas of land-based coal fired power plants. Moreover, organic Rankine cycles are suitable for heat to power conversion for low temperature heat sources. This paper is aimed at designing......-stroke diesel engine and a conventional waste heat recovery system. The results suggest that an organic Rankine cycle placed after the conventional waste heat recovery system is able to extract the sulphuric acid from the exhaust gas, while at the same time increase power generation from waste heat by 32...

  16. Comparison of moving boundary and finite-volume heat exchanger models in the modelica language

    OpenAIRE

    Adriano Desideri; Bertrand Dechesne; Jorrit Wronski; Martijn van den Broek; Sergei Gusev; Vincent Lemort; Sylvain Quoilin

    2016-01-01

    When modeling low capacity energy systems, such as a small size (5–150 kWel) organic Rankine cycle unit, the governing dynamics are mainly concentrated in the heat exchangers. As a consequence, the accuracy and simulation speed of the higher level system model mainly depend on the heat exchanger model formulation. In particular, the modeling of thermo-flow systems characterized by evaporation or condensation requires heat exchanger models capable of handling phase transitions. To this aim, th...

  17. Phase 1 of the First Solar Small Power System Experiment (experimental System No. 1). Volume 2: Appendix A - D

    Science.gov (United States)

    Clark, T. B. (Editor)

    1979-01-01

    Recommended conceptual designs for the baseline solar concentrator and electrical subsystems are defined, and trade offs that were evaluated to arrive at the baseline systems are presented. In addition, the developmental history of the Stirling engine is reviewed, the U4 configuration is described, and a Stirling engine heat pipe system is evaluated for solar application where sodium vapor is used as the heat source. An organic Rankine cycle engine is also evaluated for solar small power system application.

  18. Modeling and optimization of a binary geothermal power plant

    OpenAIRE

    2012-01-01

    A model is developed for an existing organic Rankine cycle (ORC) utilizing a low temperature geothermal source. The model is implemented in Aspen Plus® and used to simulate the performance of the existing ORC equipped with an air-cooled condensation system. The model includes all the actual characteristics of the components. The model is validated by approximately 5000 measured data in a wide range of ambient temperatures. The net power output of the system is maximized. The results suggest d...

  19. USAF Advanced Terrestrial Energy Study. Volume 2. Technology Handbook.

    Science.gov (United States)

    1983-04-01

    volume of Stirling svstems hecause the regenerator determines the dimensions of the system envelone. Table 27. STIRLING SYSTEM VOLUME (CUBIC FEET...Rankine Cycles Batteries Gas Turbines Stirling Engines Thermal Energy Storage 20. ABSTRACT (Confilime 4n roere. olde If neo**WY 41011184100140 & Wee bi A...TECHNOLOGY DESCRIPTIONS 13 Diesels, 13 Gas Turbines. 31 Stirlings , 49 Organic Rankine Cycle; 67 Fuel Cells 83 Photovoltaic Energy Conversion System, 102 Wind

  20. Thermoeconomic Analysis of Hybrid Power Plant Concepts for Geothermal Combined Heat and Power Generation

    OpenAIRE

    Florian Heberle; Dieter Brüggemann

    2014-01-01

    We present a thermo-economic analysis for a low-temperature Organic Rankine Cycle (ORC) in a combined heat and power generation (CHP) case. For the hybrid power plant, thermal energy input is provided by a geothermal resource coupled with the exhaust gases of a biogas engine. A comparison to alternative geothermal CHP concepts is performed by considering variable parameters like ORC working fluid, supply temperature of the heating network or geothermal water temperature. Second law efficiency...

  1. Experimental campaign and modeling of a low capacity waste heat recovery system based on a single screw expander

    OpenAIRE

    2014-01-01

    In recent years, due to the increasing concern over energy shortage and global warming, the interest in low grade heat recovery from industrial processes has grown dramatically. Several studies have underlined the potential of small-capacity Organic Rankine Cycle (ORC) power plants for Waste Heat Recovery (WHR) applications. For such systems, accurate models based on actual experimental data represent an important tool, in particular when control issues are considered. This paper presents an ...

  2. Heavy Duty Roots Expander Heat Energy Recovery (HD-REHER)

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, Swami [Eaton Corporation, Menomonee Falls, WI (United States)

    2015-10-01

    Eaton Corporation proposed a comprehensive project to develop and demonstrate advanced component technology that will reduce the cost of implementing Organic Rankine Cycle (ORC) Waste Heat Recovery (WHR) systems to Heavy-Duty Diesel engines, making adaptation of this fuel efficiency improving technology more commercially attractive to end-users in the next 5 to 10 year time period. Accelerated adaptation and implementation of new fuel efficiency technology into service is critical for reduction of fuel used in the commercial vehicle segment.

  3. 3D CFD analysis of an oil injected twin screw expander

    OpenAIRE

    Papeš, Iva; Degroote, Joris; Vierendeels, Jan

    2014-01-01

    Small scale Organic Rankine Cycle (ORC) systems have a big potential for waste heat recovery in the market. Due to the smaller volume flows inside these systems, non-conventional expansion technologies such as screw expanders become more interesting. Recent economic studies have shown the important role of screw machines in such cycles. However, in order to get a better understanding of the expansion behaviour in an ORC, appropriate simulation models of screw expanders are necessary. The flow...

  4. Comprehensive Model of a Single-screw Expander for ORC-Systems

    OpenAIRE

    Ziviani, Davide; Bell, Ian; van den Broek, Martijn; Paepe, Michel De

    2014-01-01

    The Organic Rankine Cycle (ORC) system is considered one of the leading technologies for waste heat recovery applications. In order to increase the overall efficiency, design improvements and optimization analyses are necessary. The expander is the key component to convert the thermal energy in useful work. Several volumetric and turbine expanders have been investigated. Among volumetric machines, scroll, twin-screw and vane-type expanders are the main technologies. Recently, a number of expe...

  5. A Selection Method for Power Generation Plants Used for Enhanced Geothermal Systems (EGS

    Directory of Open Access Journals (Sweden)

    Kaiyong Hu

    2016-07-01

    Full Text Available As a promising and advanced technology, enhanced geothermal systems (EGS can be used to generate electricity using deep geothermal energy. In order to better utilize the EGS to produce electricity, power cycles’ selection maps are generated for people to choose the best system based on the geofluids’ temperature and dryness conditions. Optimizations on double-flash system (DF, flash-organic Rankine cycle system (FORC, and double-flash-organic Rankine cycle system (DFORC are carried out, and the single-flash (SF system is set as a reference system. The results indicate that each upgraded system (DF, FORC, and DFORC can produce more net power output compared with the SF system and can reach a maximum net power output under a given geofluid condition. For an organic Rankine cycle (ORC using R245fa as working fluid, the generated selection maps indicate that using the FORC system can produce more power than using other power cycles when the heat source temperature is below 170 °C. Either DF or DFORC systems could be an option if the heat source temperature is above 170 °C, but the DF system is more attractive under a relatively lower geofluid’s dryness and a higher temperature condition.

  6. A multi-objective optimization approach for the selection of working fluids of geothermal facilities: Economic, environmental and social aspects.

    Science.gov (United States)

    Martínez-Gomez, Juan; Peña-Lamas, Javier; Martín, Mariano; Ponce-Ortega, José María

    2017-07-17

    The selection of the working fluid for Organic Rankine Cycles has traditionally been addressed from systematic heuristic methods, which perform a characterization and prior selection considering mainly one objective, thus avoiding a selection considering simultaneously the objectives related to sustainability and safety. The objective of this work is to propose a methodology for the optimal selection of the working fluid for Organic Rankine Cycles. The model is presented as a multi-objective approach, which simultaneously considers the economic, environmental and safety aspects. The economic objective function considers the profit obtained by selling the energy produced. Safety was evaluated in terms of individual risk for each of the components of the Organic Rankine Cycles and it was formulated as a function of the operating conditions and hazardous properties of each working fluid. The environmental function is based on carbon dioxide emissions, considering carbon dioxide mitigation, emission due to the use of cooling water as well emissions due material release. The methodology was applied to the case of geothermal facilities to select the optimal working fluid although it can be extended to waste heat recovery. The results show that the hydrocarbons represent better solutions, thus among a list of 24 working fluids, toluene is selected as the best fluid. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Análise teórica da recuperação de calor para geração de energia em indústrias de cimento e cal utilizando o ciclo de Rankine orgânico

    Directory of Open Access Journals (Sweden)

    Ricardo Carrasco Carpio

    2015-06-01

    Full Text Available O presente trabalho consiste em uma apresentação do estado da arte do Ciclo Rankine Orgânico, um ciclo termodinâmico que usa um fluido orgânico como fluido de trabalho e que pode ser usado para recuperação de calor rejeitado em processos industriais, gerando assim energia elétrica para abastecer a própria indústria, o que consequentemente causa uma redução no custo de produção da empresa. São apresentados alguns fluidos orgânicos e alguns de seus parâmetros termodinâmicos.Palavras-chave: Cogeração. Ciclo Rankine Orgânico. Fluidos de Trabalho.ABSTRACTTheoretical analysis of heat recovery for power generation in cement and lime industries using the organic Rankine cycleThis work aims to present the state of the art of the Organic Rankine Cycle, a thermodynamic cycle that uses an organic fluid as a working fluid that can be used to recover the rejected heat in industrial processes, thus generating electricity to supply industry itself, which causes a reduction in the production cost of the company. It also presents some organic fluids and some of their thermodynamic parameters.Keywords: Cogeneration. Organic Rankine Cycle. Working Fluids.

  8. Kommunikationsschulung mittels "Standardisierter Eltern" im Fachbereich der Pädiatrie [Communication training using "standardised parents" in paediatrics

    Directory of Open Access Journals (Sweden)

    Hoffmann, Katja

    2007-05-01

    Full Text Available [english] Introduction: Communicative competence is essential for daily medical routine. The usefulness of communication-trainings for physicians is described in various publications. However, specific trainings in paediatrics are rarely found. A characteristic for paediatric work is that the primary communication is not only with the patient – the child – but also with the parents. Beside self-assessment external assessment by parents can be used for evaluation of paediatrician’s communicative skills.Methods: 28 paediatric residents (intervention group n = 14; control group n = 14 of the University Children’s Hospital of Heidelberg took part in a communication training using standardised parents and -patients (SP, video recording and feedback by peers, SPs and supervisors. Data of self-evaluated communicative competence in contact with parents was collected from all participants before and after the training of the intervention group. In addition there was an assessment of parents’ satisfaction with the paediatricians-parents communication concerning their children’s treatment nine weeks before and nine weeks after the training (n = 248. A follow-up survey to record the transfer into clinical practice was conducted with the participants after six months.Results: After the training participants of the intervention group showed an increased feeling of communicative competence in reference to communicative situations that were explicitly practiced in the training. The external assessment by parents generally showed a positive evaluation of paediatricians’ communication skills. However, a group effect was not found. In the follow-up survey participants reported an improved self-perception and specific elements of the training that facilitated the daily clinical practice with parents and their children. Discussion: The training of specific relevant clinical situations lead to an increase in perceived communicative competence and competence in handling difficult encounters with parents. Communication trainings should be integrated not only into the medical student education but also into post-graduate education curricula. [german] Einführung: Kommunikative Kompetenzen sind wesentlich für den ärztlichen Alltag. In der Literatur wird vielfach der Nutzen von Kommunikationsschulungen für Ärzte beschrieben, über gezielte Schulungen für den Fachbereich Pädiatrie finden sich nur vereinzelt Berichte. Die Besonderheit der pädiatrischen Versorgung besteht dabei im Wesentlichen darin, dass nicht nur die Kommunikation zum Patienten – dem Kind –, sondern auch zu dessen Eltern oder Bezugspersonen eine entscheidende Rolle spielt. Zur Überprüfung kommunikativer Fähigkeiten von Pädiatern können neben Selbsteinschätzungen auch Fremdeinschätzungen durch Eltern dienen.Methode: 28 Assistenzärzte (Interventionsgruppe n = 14; Kontrollgruppe n = 14 der Universitätsklinik für Kinder- und Jugendmedizin in Heidelberg nahmen an einer Kommunikationsschulung teil. Diese beinhaltete Übungsgespräche mit standardisierten Eltern und -Patienten (SP, Videoaufzeichnungen sowie Feedback von SPs, Peers und Supervisoren. Daten zur Selbsteinschätzung der eigenen kommunikativen Kompetenz wurden vor und nach der Schulung der Interventionsgruppe von allen Teilnehmern erhoben. Weiterhin wurde neun Wochen vor und neun Wochen nach Abschluss der Schulung eine Elternbefragung bei n = 248 Eltern durchgeführt, in der die Zufriedenheit mit dem Arztkontakt hinsichtlich der Arzt-Eltern Kommunikation erfasst wurde. Nach 6 Monaten schloss sich eine Nachbefragung bei den Teilnehmern zum Transfer in den Klinikalltag an.Ergebnis: Bei den Teilnehmern der Interventionsgruppe zeigte sich im Gegensatz zur Kontrollgruppe nach Abschluss der Schulung eine signifikante Steigerung der subjektiven Kompetenzeinschätzung in Bezug auf die kommunikativen Situationen, die speziell in der Schulung trainiert wurden. Die Fremdeinschätzung durch die Eltern ergab eine generell sehr positive Bewertung der Ärzte, es ließ sich jedoch kein Gruppeneffekt nachweisen. Im Langezeitverlauf berichteten die Teilnehmer von einer verbesserten Selbstwahrnehmung und benannten konkrete Elemente der Schulung, die ihnen die tägliche klinische Arbeit im Kontakt mit Eltern erkrankter Kinder erleichterten.Diskussion: Das Training von spezifischen, für den klinischen Alltag typischen Situationen führt zu einer Verbesserung der Selbsteinschätzung kommunikativer Kompetenzen bezüglich des Umgangs mit schwierigen Situationen im Elternkontakt. Eine Integration von Kommunikationsschulungen nicht nur in das Medizinstudium, sondern auch in postgraduierte Ausbildungs-Curricula erscheint daher sinnvoll.

  9. Monitoring effects of river restoration on groundwater with radon; Ueberwachung der Auswirkungen von Flussaufweitungen auf das Grundwasser mittels Radon

    Energy Technology Data Exchange (ETDEWEB)

    Hoehn, Eduard [Eawag, Eidgenoessische Anstalt fuer Wasserversorgung, Abwasserreinigung und Gewaesserschutz, Duebendorf (Switzerland)

    2007-03-15

    The restoration of the perialpine river Toess in a floodplain of northern Switzerland (Linsental) included the removal of bank reinforcements and tracer studies in the river and in oberservation wells of the adjacent alluvial groundwater. The river water is continuously recharging the aquifer system and the groundwater is used extensively as drinking water. Radon activity concentrations of freshly infiltrated groundwater are interpreted as radon groundwater age between the river and a well. A first flood after the restoration operations resulted in a widening of the river bed and in a reduction of the flow distance to the wells. Sixteen days after a second flood, the results of radon measurements were compared with those from before the restoration. The radon age of the groundwater between the river and the wells decreased, probably as a result of the reduction of the flow distances. Concentrations of autochthonous and coliform bacteria increased after the restoration operation and even more one day after the first flood. Thus the findings on the bacteria corroborate the interpretation of the radon concentrations. The restoration has not yet reduced the quality of the groundwater, which is pumped for drinking water. The study is contributing to the solution of land-use conflicts between river restoration and the supply of drinking water from the alluvial groundwater. (orig.) [German] Die Renaturierung des voralpinen Flusses Toess in der Schotterebene des Linsentals (suedlich Winterthur, Nordschweiz) mit einer Befreiung von seinen Uferverbauungen gab Anlass zu Traceruntersuchungen im Fluss und im Grundwasser des kiessandigen Schotters. In diesem Gebiet infiltriert der Fluss ueberall und immer natuerlicherweise ins Grundwasser, welches stark als Trinkwasser genutzt wird. Radon-Aktivitaetskonzentrationen von frisch infiltriertem Grundwasser wurden interpretiert als Radon-Grundwasseralter fuer Strecken zwischen dem Fluss und Grundwasserbeobachtungsrohren. Nach einem ersten Hochwasser bewirkten die Renaturierungsmassnahmen eine Aufweitung des Ufers und eine Verringerung der Fliessdistanz des infiltrierenden Wassers zu den Rohren. Im Vergleich mit Radonmessungen vor diesen Massnahmen, resultierten Messungen, die 16 Tage nach einem zweiten Hochwasser durchgefuehrt wurden, in einer Verringerung der Radon-Grundwasseralter auf dieser Strecke, dies als Folge der Verringerung der Fliessdistanzen. Die Zahlen von autochthonen und coliformen Bakterien stiegen bereits bei einer Messung nach der Befreiung des Ufers und dann besonders bei einer Messung einen Tag nach dem ersten Hochwasser. Damit stuetzen diese Befunde die Interpretation der Radonmessungen. Auf die Trinkwasserqualitaet wirkte sich die Flussaufweitung hingegen bislang nicht aus. Solche Untersuchungen leisten einen Beitrag zur Loesung des raumwirksamen Nutzungskonflikts zwischen Flussrenaturierung und Grundwassernutzung als Trinkwasser. (orig.)

  10. Aerodynamic flow-control with dielectric barrier discharge plasma actuators; Aerodynamische Stroemungssteuerung mittels dielektrischer Barriereentladungs-Plasmaaktuatoren

    Energy Technology Data Exchange (ETDEWEB)

    Wilke, Joern Bastian

    2009-07-01

    In this work, measurements of the spatial-temporal evolution of velocity vector fields, induced by a dielectric barrier discharge plasma actuator, are presented for the first time in order to enhance the understanding of these actuators. A procedure for calculating the body forces-induced by these actuators-from the measured velocity vector fields is also described. A number of parametric studies with plasma actuators, were performed in order to identify the relevant parameter dependencies concerning the effectiveness and the efficiency for an optimization of these actuators. A new phenomenological model for the simulation of the aerodynamic effect of plasma actuators was developed, which can be used to produce more accurate numerical results than existing models. The suitability of plasma actuators in aerodynamic applications was investigated for two different cases. In the first case, a circulation control of a rotorcraft airfoil by plasma actuators, the actuators were arranged such that the gurney flap active principle was achieved and observed for the first time. In the second case, a plasma actuator was mounted on the leading edge of a delta wing to successfully demonstrate flow control up to Re=10{sup 6}. The three velocity components in the plane normal to the flow velocity were measured, enabling the analysis of the change of the leading edge vortices due to plasma actuation. (orig.)

  11. Development and standard of batter slope monitoring by means of simple telemetering. Entwicklung und Stand von Boeschungsbeobachtungen mittels einfacher Distanzmessungen

    Energy Technology Data Exchange (ETDEWEB)

    Duddek, H.

    1990-11-01

    In the search for mainly automatic measuring techniques that furnish real-time areal data on deformations in marginal batters of opencast workings, it was decided inter alia to adopt the technique of direct linear measurement across the workings at the brown coal opencast mines in the Rhineland. The present paper describes the development of this technique from the use of instruments which initially were operated manually to the introduction of automatic measuring stations. The successful application of this technique in all the opencast workings in the Rhineland brown coal mining area is discussed. Since the accuracy obtained in electro-optical telemetering depends to a large extent on the meteorological conditions, it can hardly be increased with the instruments at present available. Hence, it is essential that two-colour telemeters which are perfected for field-work and are not refraction-prone should be developed. (orig.).

  12. Simultane Untersuchung der Diffusion von intrinsischen und extrinsischen Defekten in CdTe mittels ortsaufgelöster Photolumineszenzspektroskopie

    OpenAIRE

    2013-01-01

    Die vorliegende Arbeit beschäftigt sich mit der Untersuchung von Diffusionsphänomenen in CdTe. Radiotracerexperimente, bei denen mit Gruppe-I-Elementen dotiertes CdTe unter Cd-Dampfdruck getempert wurde, ergaben Konzentrationsprofile, welche die Diffusion der Fremdatome gegen ihren Konzentrationsgradienten voraussetzen (Uphill-Diffusion). In früheren Arbeiten wurde ein Modell entwickelt, das diese Konzentrationsprofile quantitativ mit der Diffusion der intrinsischen Defekte des Cd-Untergitter...

  13. X-ray inspection of large LSAW pipes using modern filmless radiography; Moderne Roentgenpruefung mittels filmloser Radiographie an LSAW Grossrohren

    Energy Technology Data Exchange (ETDEWEB)

    Kersting, Thomas; Liessem, Andreas; Oesterlein, Ludwig; Schuster, Stefan [EUROPIPE, Muelheim a.d. Ruhr (Germany); Schoenartz, Norbert [Salzgitter Mannesmann Forschung, Duisburg (Germany)

    2008-07-01

    Large-diameter pipes with longitudinal welds for transporting combustible media are subject to the most rigid safety specifications. For further improvement of the nondestructive testing process, EUROPIPE - the market leader in the field of large-diameter pipes for the oil and gas industry - invested in digital radiographic inspection, which completely replaces classic X-ray films. The new system comprises two separate X-ray chambers in order to keep up with the production rate. Each X-ray chamber contains two digital panel detectors and two X-ray tubes. EUROPIPE is one of the first organisations worldwide to introduce this technology in automatic serial production of large-diameter pipes. [German] Fuer laengsnahtgeschweisste Grossrohre zum Transport von brennbaren Medien gelten hoechste Sicherheitsanforderungen. Zur weiteren Verbesserung des zerstoerungsfreien Pruefprozesses hat EUROPIPE als Marktfuehrer fuer Grossrohre der Oel- und Gasindustrie in die digitale Roentgenpruefung investiert und damit komplett den klassischen Roentgenfilm ersetzt. Die neue Anlage besteht aus zwei separaten Roentgenkammern, um die Taktzeiten des Produktionsflusses einhalten zu koennen. In jeder Roentgenkammer befinden sich je zwei digitale Flaechendetektoren und zwei Roentgenroehren. EUROPIPE ist eines der ersten Unternehmen, das diese Technologie in die automatisierte Serienproduktion von Grossrohren eingefuehrt hat.

  14. Quantifizierung von Lignin aus Papierfabriksabwässern mittels Py-GC/MS und UV/VIS

    OpenAIRE

    Schiegl, Christian

    2008-01-01

    Eine Methode zur quantitativen Bestimmung von Fichtenlignin aus Papierfabriksabwässern und Belebtschlamm wurde entwickelt. Das Lignin wurde durch Curie-Punkt-Pyrolyse thermisch gespalten. Die Fragmente wurden gaschromatographisch aufgetrennt, massenspektrometrisch identifiziert und quantifiziert. Durch Einsatz dieser Methode an realen Papierfabriksabwässern konnte eine Bilanzierung der Stoffströme des Lignins durchgeführt werden. Es zeigte sich, dass während des biologischen Reinigungsprozess...

  15. Quantitative Bestimmung von Veränderungen verschiedener Körperfettkompartimente mittels MR-Bildgebung im Rahmen einer Lebensstilintervention

    OpenAIRE

    Brenner, Sonja

    2010-01-01

    Die im Jahre 2008 veröffentlichte "Nationale Verzehrstudie II" legt dar, dass etwa jeder fünfte Bundesbürger einen BMI von über 30 kg/m2 hat, was mit einem erhöhten Risiko für Fettstoffwechselstörungen und Diabetes einher geht. Außerdem zeigen viele Personen mit einem erhöhten BMI auch ein metabolisches Syndrom, welches sich unter anderem durch eine bauchbetonte Adipositas auszeichnet. In vorliegender Abhandlung wurden die Veränderungen der Körperfettkompartimente (besonders der als stoffwech...

  16. Rapid total body fat measurement by magnetic resonance imaging: quantification and topography; Schnelle Ganzkoerperfettmessung mittels MRT: Quantifizierung und Topografie

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, F.M.; Hunold, P.; Greiff, A. de; Nuefer, M.; Barkhausen, J.; Ladd, S.C. [Uniklinikum Essen (Germany). Inst. fuer Diagnostische und Interventionelle Radiologie; Ruehm, S. [David Geffen School of Medicine at UCLA (United States). Dept. of Radiology

    2007-05-15

    Purpose: To evaluate a rapid and comprehensive MR protocol based on a T1-weighted sequence in conjunction with a rolling table platform for the quantification of total body fat. Materials and Methods: 11 healthy volunteers and 50 patients were included in the study. MR data was acquired on a 1.5-T system (Siemens Magnetom Sonata). An axial T1-weighted flash 2D sequence (TR 101, TE 4.7, FA 70, FOV 50 cm, 205 x 256 matrix, slice thickness: 10 mm, 10 mm interslice gap) was used for data acquisition. Patients were placed in a supine position on a rolling table platform capable of acquiring multiple consecutive data sets by pulling the patient through the isocenter of the magnet. Data sets extending from the upper to lower extremities were collected. The images were analyzed with respect to the amount of intraabdominal, subcutaneous and total abdominal fat by semi-automated image segmentation software that employs a contour-following algorithm. Results: The obtained MR images were able to be evaluated for all volunteers and patients. Excellent correlation was found between whole body MRI results in volunteers with DEXA (r{sup 2} = 0.95) and bioimpedance (r{sup 2} = 0.89) measurements, while the correlation coefficient was 0.66 between MRI and BMI, indicating only moderate reliability of the BMI method. Variations in patients with respect to the amount of total, subcutaneous, and intraabdominal adipose tissue was not related to standard anthropometric measurements and metabolic lipid profiles (r{sup 2} = 0,001 to 0.48). The results showed that there was a significant variation in intraabdominal adipose tissue which could not be predicted from the total body fat (r{sup 2} = 0.14) or subcutaneous adipose tissue (r{sup 2} = 0.04). Although no significant differences in BMI could be found between females and males (p = 0.26), females showed significantly higher total and subcutaneous abdominal adipose tissue (p < 0.05). Conclusion. (orig.)

  17. Monitoring of small heat pumps using standardised tests in 2009; Monitoring von Klein-Waermepumpen mittels Normpruefungen 2009 - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Eschmann, M.

    2010-02-15

    This final report for the Swiss Federal Office of Energy (SFOE) reports on the monitoring in 2009 of small heat pumps with heating powers up to 100 kW using standardised tests. The authors note that, in 2009, more heat pump tests were carried out than in the years before as a result of improved facilities and procedures. Also, after initial improvement in previous years, Coefficient of Performance (COP) values have deteriorated. This is, according to the authors, due to lower prices on the market. This means that heat pumps are built cost-optimised and are not developed to reach the maximum energetic efficiency. The tests carried out are listed and the results obtained are presented in graphical form and commented on. The EHPA/DACH quality label and the required COP values are reviewed.

  18. Miniplant technology for heavy-metal precipitation by means of reactive extraction processes; Miniplanttechnik zur Schwermetallentfernung mittels reaktiver Extraktionsverfahren

    Energy Technology Data Exchange (ETDEWEB)

    Bart, H.J.; Schoeneberger, A. [Kaiserslautern Univ. (Germany). Lehrstuhl Thermische Verfahrenstechnik

    1999-07-01

    The development of novel techniques and their apparatus nowadays involves increasingly laboratory-scale technical systems (miniplant) in combination with simulation programs. For the precipitation of pollutants, especially heavy metals, from watery solutions, selective-action liquid ion exchangers are excellently suited, which are used in systems of various technical designs. The paper discusses their potential of application, the advantages and shortcomings of liquid-liquid extraction (counter-flow technique), of non-dispersive extraction (membrane technique) and of extractant-impregnated resins (packed-bed process) as well as their integration in miniplant systems. (orig.) [German] Bei der Entwicklung neuer Verfahren und bei deren apparativer Umsetzung werden heutzutage verstaerkt Anlagen im Labormassstab (Miniplant) in Kombination mit Simulationsprogrammen eingesetzt. Zur Entfernung von Schadstoffen, insbesondere Schwermetallen, aus waessrigen Loesungen eignen sich hervorragend selektiv wirkende fluessige Ionentauscher, die in unterschiedlicher Apparatetechnik zur Anwendung kommen. Das Einsatzpotential sowie Vor- und Nachteile der fluessig-fluessig Extraktion (Gegenstromverfahren), der nicht-dispersiven Extraktion (Membranverfahren), von extraktionsmittel-impraegnierten Harzen (Festbettverfahren) und die Einbindung in Miniplants werden diskutiert. (orig.)

  19. Nitroxid-vermittelte Polymerisation mittels NMR-Sonden tragender Initiatoren zur Darstellung von coil-rod-coil-Blockcopolymeren

    OpenAIRE

    Tietz, Marco

    2016-01-01

    A systematic synthesis for coil-rod-coil(c-r-c) block copolymers with differing material characteristics should lead to the usage of c-r-c block copolymers as surface probes and for the study of the self assembling behavior of c-r-c block copolymers. Therefor 2,2,5-Trimethyl-4-phenyl-3-azahexane-3-nitroxide (TIPNO) based alkoxyamines with covalently attached NMR probes where synthesized starting from nitroxides and functionalized styrenes. These alkoxyamines were used as initiators f...

  20. The critical speed of the Deutsche Reichsbahn's class-05 steam locomotive; Berechnung der kritischen Geschwindigkeit mittels Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Eckstein, Johannes [Stuttgart Univ. (Germany). Inst. fuer Technische und Numerische Mechanik; Heer, Andreas [Bosch Engineering GmbH, Abstatt (Germany). Bremsregelsysteme; Meinke, Peter [IAT Ingenieurgesellschaft fuer Angewandte Technologie mbH, Gauting (Germany); Wiese, Christoph [Stuttgart Univ. (Germany). Inst. fuer Leistungselektronik und Elektrische Antriebe, Stuttgart

    2009-07-01

    Modern high-speed trains are equipped with running gear that has been optimised for lateral stability at normal operational speeds and the minimisation of phenomena such as hunting oscillations. What, however, was the situation when the new world railway speed record of 200.4 km/h was established on 11 May 1936 by a steam locomotive, 05 002, hauling a rake of four passenger coaches? In those days, nobody was in a position to calculate critical speeds. It has only been since we have had access to computers that it has been possible to establish critical speeds mathematically by running simulations (using programs like SIMPACK). The simulation's output has shown that, provided the tender was rigidly coupled to the locomotive, these two vehicles together would have had stable running properties up to approximately 245 km/h. Evidence has at last been produced to show that the record-breaking run of 200.5 km/h was not in any danger on account of excessive instability due to hunting oscillations. (orig.)

  1. Evaluation eines modifizierten Auxanogramms zur Differenzierung von Malassezia-Hefen mittels ITS1-rDNA-Sequenzierung

    OpenAIRE

    Uhlich, Maren

    2014-01-01

    Malassezia-Hefen sind die Ursache für eine Reihe dermatologischer Erkrankungen wie z.B. der Pityriasis versicolor. Ihre Klassifikation ist in den letzten Jahren immer mehr in den Vordergrund gerückt. Verschiedene phänotypische und molekularbiologische Nachweismethoden wurden zur Differenzierung unterschiedlicher Stämme entwickelt. Anhand dieser Studie wurde die Übereinstimmungsrate der Zuordnungen von Malassezia-Hefen zwischen der etablierten molekularbiologischen Methode nach Makimura et...

  2. Using geothermal energy to heat railway platforms; Nutzung der Erdwaerme zur Beheizung von Bahnsteigen. Umweltfreundliche Temperierung von Personenverkehrsflaechen mittels Geothermie

    Energy Technology Data Exchange (ETDEWEB)

    Katzenbach, R. [Inst. Versuchsanstalt fuer Geotechnik der TU Darmstadt (Germany); [Technische Univ. Darmstadt (Germany). Inst. fuer Geotechnik; Waberseck, T. [Inst. fuer Geotechnik der TU Darmstadt (Germany); [Hering Bau GmbH und Co.KG, Burbach (Germany); Bolk, P. [Hering Bau GmbH und Co. KG, Burbach (Germany); [Meierhans und Partner GmbH, Mainz (Germany); Steinbach, C. [Meierhans und Partner GmbH, Mainz (Germany)

    2007-07-01

    In recent years, increasing recourse has been had to geothermal energy to heat buildings in an environmentally friendly and resource-saving manner. For a number of years, efforts have also been made to tap the enormous potential offered by geothermal energy for transport route operation. One line of development in this field is to use geothermal heat to warm passenger transport areas such as railway platforms, which can be kept free of snow and ice in winter using this regenerative energy source. (orig.)

  3. Ein empirischer Vergleich der Prozessaufzeichnungsmethoden Mouselab und Eyetracking bei Präferenzmessungen mittels Choice-based Conjoint Analyse

    DEFF Research Database (Denmark)

    Meissner, Martin; Decker, Reinhold; Pfeiffer, Jella

    2010-01-01

    In choice-based conjoint (CBC) analysis respondents’ decisions in choice settings are used to determine relevant attributes and attribute levels of the products considered. Yet, the cognitive process preceding the choice decision is usually ignored. The eye tracking technique can be used to gain...

  4. Repair of damage to wind turbine foundations. Nondestructive ultrasonic testing; Sanierung von Fundamentschaeden. Zerstoerungsfreie Pruefung mittels Ultraschall

    Energy Technology Data Exchange (ETDEWEB)

    Zimmer, Hans-Peter [CONCRETE CARE, Berlin (Germany)

    2009-07-01

    Damage of foundations is often not visible from the surface. And even visible cracks do not show how far they reach inside the foundation. Prior to any repair measures, detailed analysis and a careful and precise description of the damage pattern are required. The biggest challenge is the detection of hidden damage and its correct description. Nondestructive methods are the method of choice. (orig.)

  5. Reducing nitrogen oxides in exhaust gases by means of urea. Final report; Reduzierung von Stickoxiden in Abgasen mittels Harnstoff. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Koebel, M.; Elsener, M.; Marti, T. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1994-11-01

    Ammonia has been used for about twenty years as a selective reducing agent for reducing NO{sub x} in lean exhaust gases containing excess oxygen. Although urea has distinct advantages compared with ammonia (solid substance, cheap, practically nontoxic, not explosive) it has hardly been considered for this purpose. In the present work the possibilities of using aqueous urea solutions for the DeNOx processes based on selective catalytic reduction (SCR) and selective non catalytic reduction (SNCR) are explored. SCR: Urea-SCR poses little problems: If the process equipment is properly designed, no appreciable emissions of flue gas components related to urea are found, e.g. isocyanic acid, hydrogen cyanide, nitrous oxide, urea, biuret, cyanuric acid and melamine. On the other hand, like ammonia, use of urea leads to an emission of ammonia which limits the maximum attainable degree of NO{sub x} reduction. With industrial bulk catalysts based on TiO{sub 2}-WO{sub 3}-V{sub 2}O{sub 5} and gas hourly space velocities of 10`000 h{sup -1}, NO{sub x} reductions of over 98% at an ``ammonia slip`` below 10 ppm may be attained. SNCR: The use of urea instead of ammonia shifts the optimum temperature window upwards by about 50 K. Besides an ``ammonia slip``, some isocyanic acid is found, and the emissions of carbon monoxide and nitrous oxide are definitely higher. As nitrous oxide is considered to be a greenhouse gas and a scavenger of stratospheric ozone, the use of urea is no longer recommended in future SNCR installations. If the advantages of storage convenience of urea to be combined optimally with the advantages of ammonia as selective reducing agent, the hydropyrolysis of urea in an external reactor is a possible solution. (author) 38 figs., 5 tabs., 36 refs.

  6. Asymmetrische Totalsynthese von 16(S)-Iloprost und 3-Oxa-16(S)-Iloprost mittels der Azoen-Strategie

    OpenAIRE

    2005-01-01

    The present dissertation describes completely stereocontrolled asymmetric syntheses of 16S-iloprost and of 16S-3-oxa-iloprost by a azoene strategy. As Ilomedin and Ventavis registrated iloprost (1:1 mixture of diastereomers at C16) serves as a drug against ischemic heart disease, peripheral vascular disease and primary pulmonary hypertension. The 16S-diastereomer is 5 to 20 times more potent than the 16R-diastereomer in inhibiting collagen-induced platelet aggregation. 3-oxa-16S-iloprost shou...

  7. Gadolinium recovery from aqueous pharmaceutical residuals by pulsed electrical discharge; Rueckgewinnung von Gadolinium aus pharmazeutischen Abwaessern mittels gepulster elektrischer Entladung

    Energy Technology Data Exchange (ETDEWEB)

    Lorenz, Tom; Froehlich, Peter [TU Bergakademie Freiberg (Germany); Seifert, Martin; Jacob-Seifert, Karin [FNE Entsorgungsdienste GmbH, Freiberg (Germany)

    2017-02-15

    Advanced oxidation process (AOP) is an oxidation step releasing reactive oxygen species by pulsed electrical discharge in aqueous systems. In contrast to processes generating ozone by external UV radiation this method is feasible for turbid liquids with solid particles. This method is currently used in particular in the field of purification of chemically polluted waste waters. In the present application AOP is applied for partial degradation of the organic ligand system of a gadolinium X-ray contrast agent to separate gadolinium subsequently by adding caustic soda to precipitate > 99% of gadolinium.

  8. Cancer and inflammation. Differentiation by USPIO-enhanced MR imaging; Tumor oder Entzuendung. Differenzierung mittels USPIO-verstaerkter Magnetresonanztomografie

    Energy Technology Data Exchange (ETDEWEB)

    Seyfer, P. [Universitaetsklinikum Giessen und Marburg GmbH, Marburg (Germany). Klinik fuer Diagnostische und Interventionelle Radiologie

    2014-12-15

    Purpose: To assess ultrasmall superparamagnetic iron oxide particles (USPIO)-enhanced MR imaging for the differentiation of malignant from benign, inflammatory lesions. In this study, approved by the local animal care committee, VX2 carcinoma and intramuscular abscesses were implanted into the hind thighs of New Zealand White rabbits. MR imaging was performed pre contrast and serially for 24 h after the injection of USPIO. MR findings were compared with histopathologic results based on Prussian blue stains for the presence of iron. Twenty-four hours after the Ferumoxtran-injection, no changes were observed in VX2 carcinomas, whereas a mean reduction of the contrast-to-noise ratio (CNR) of approximately 90% was noticed in abscesses as well as in necrotic tumors. On histopathologic examination, abscess and necrotic parts of the tumor were found to include iron-containing monocytes demonstrating that the reduction in CNR was caused by USPIO-tagged monocytes. Our results prove the ability of USPIO-enhanced MRI to differentiate benign, inflammatory from malignant lesions.

  9. Positionsspezifischer Nachweis und relative Quantifizierung von Modifikationen des alpha-s1-Caseins in Milch mittels MALDI-TOF-MS

    OpenAIRE

    2013-01-01

    Milch und Milchprodukte spielen eine bedeutende Rolle in der menschlichen Ernährung. Vor der Abgabe an den Verbraucher wird Milch in den allermeisten Fällen hitzebehandelt, um mikrobielle Stabilität sicherzustellen und die Haltbarkeit zu verlängern. Allerdings kann diese Hitzebehandlung die in Milch enthaltenen Nährstoffe, unter anderem Kohlenhydrate, Lipide, Proteine und Vitamine, erheblich schädigen. Vitamine werden durch starke Erhitzung zerstört, bei den Lipiden kann es zu Abbaureaktionen...

  10. Ein empirischer Vergleich der Prozessaufzeichnungsmethoden Mouselab und Eyetracking bei Präferenzmessungen mittels Choice-based Conjoint Analyse

    DEFF Research Database (Denmark)

    Meissner, Martin; Decker, Reinhold; Pfeiffer, Jella

    2010-01-01

    , instead of eye tracking, influences the way information is acquired and processed and whether respectively how this affects the validity of CBC results. The empirical study shows that Mouselab in fact changes the information acquisition process, but this does not affect the quality of the preference......In choice-based conjoint (CBC) analysis respondents’ decisions in choice settings are used to determine relevant attributes and attribute levels of the products considered. Yet, the cognitive process preceding the choice decision is usually ignored. The eye tracking technique can be used to gain...... additional insights on how information is processed in the context of preference measurement. However, because of the technical requirements, an efficient application of eye tracking is often hard to realize in managerial practice. Therefore, the use of alternative process-tracing approaches like Mouselab...

  11. Thermal spraying of corrosion protection layers in biogas plants; Erzeugung von Korrosionsschutzschichten fuer Bioenergieanlagen mittels Thermischen Spritzens

    Energy Technology Data Exchange (ETDEWEB)

    Crimmann, P.; Dimaczek, G.; Faulstich, M. [ATZ Entwicklungszentrum, Sulzbach-Rosenberg (Germany)

    2004-07-01

    Corrosion in plants for the energetic conversion of biomass is a severe problem that often causes premature damage of components. Thermal spraying is a process for the creation of corrosion protection layer. An advantage of thermal spraying is that as well as each material can be used as layer material. First practical results demonstrated that thermal spraying has the potential to create coatings to protect components against high temperature corrosion as well as biocorrosion. Layer materials are for example nickel base alloys (high temperature corrosion) and titan alloys (biocorrosion). Further investigations are necessary in order to examine whether cost-efficient coatings also contribute to the corrosion protection (e.g. polymer materials against biocorrosion). (orig.)

  12. Analysis on Abnormal Temperature of 150MW Air-Cooled Turbo-Generator%150MW空冷汽轮发电机温度异常分析

    Institute of Scientific and Technical Information of China (English)

    高阳; 于涛

    2011-01-01

    首先对出现温度异常的机组进行了通风试验,测试了其运行时的实际风量;其次利用网络法计算了发电机总风量及其风量分配,并在此基础上,利用有限元法对其定子温度场进行了计算;最后分析了150MW空冷汽轮发电机在运行中出现定子铁心温度和定子线圈温度异常的原因.

  13. 1000MW发电机定子运输端盖的优化设计%Design Improvement for Transportation Flange of 1000MW Turbo-generator Stator

    Institute of Scientific and Technical Information of China (English)

    谢玉增; 梁洪涛; 刘庆河; 杜金程; 曹凤波; 牟松

    2014-01-01

    1000MW汽轮发电机定子铁路运输方案采用运输端盖结构形式.在设计过程中,结合有限元建模分析手段进行了结构形式及结构尺寸的优化设计研究,以达到重量更轻、结构应力分布更合理、运输安全系数更高的目标,同时避免机座变形对发电机内部结构产生危害.

  14. 东方大型空冷汽轮发电机的设计开发%Large Capacity Air-cooled Turbogenerator Developed by DEC

    Institute of Scientific and Technical Information of China (English)

    令红兵; 胡德剑

    2008-01-01

    在市场需求和新技术的共同推动下,空冷汽轮发电机单机容量持续提高,近期东方电机研究开发出了258MVA的新机型,本文重点介绍了此机型的通风研究、结构特点以及运行测试结果.

  15. 低温地热发电有机朗肯循环的优化%Optimization of the Low-temperature Geothermal Heat Powered Organic Ranline Cycle

    Institute of Scientific and Technical Information of China (English)

    王辉涛; 王华; 葛众; 冷婷婷

    2011-01-01

    采用(火用)分析方法及PR状态方程,建立了低温地热发电有机朗肯循环的工质优选及主要参数优化热力学方法.比较计算了以10种干流体有机工质为循环工质的低温地热发电有机朗肯循环的输出功率、(火用)效率及其余主要热力性能.结果表明,低温地热发电有机朗肯循环的性能极大地受工质的物性及蒸发温度的影响.总体来看,随着工质临界温度的升高,输出功率及(火用)效率呈下降趋势,而热效率及地热流经换热后的排放(或回灌)温度呈上升趋势.R227ea是低温地热发电有机朗肯循环较理想的工质,以其作工质的有机朗肯循环系统的输出功率及(火用)效率最高,蒸发压力及凝结压力亦处于较合适的范围.低温地热发电有机朗肯循环存在最佳蒸发温度,在最佳蒸发温度下的系统可获得最大的输出功率及(火用)效率.%The exergetic analysis method and PR equation of state were utilized to establish the thermodynamic method of working fluid selection and the optimization of the low-temperature geothermal heat powered organic Rankine cycles. Thermal performances, including power output, exergy efficiency, etc. of low-temperature geothermal heat powered organic Rankine cycles using 10 kinds of dry fluids as working fluids, were calculated and compared. The results show that: The performances of low-temperature geothermal heat powered organic Rankine cycle are greatly affected by evaporation temperature and working fluid's thermal properties. As the critical temperature of working fluid increases, the output power and exergy efficiency show a decreasing trend, but the cycle thermal efficiency and the final discharge (or rejection)temperature of the geothermal fluid show an increasing trend as a whole. Moreover, the organic Rankine cycle charged with R227ea (heptafluoropropane) gets the highest power output and exergy efficiency, and the evaporation and condensation pressures are

  16. Steam microturbines in distributed cogeneration

    CERN Document Server

    Kicinski, Jan

    2014-01-01

    This book presents the most recent trends and concepts in power engineering, especially with regard to prosumer and civic energy generation. In so doing, it draws widely on his experience gained during the development of steam microturbines for use in small combined heat and power stations based on the organic Rankine cycle (CHP-ORC). Major issues concerning the dynamic properties of mechanical systems, in particular rotating systems, are discussed, and the results obtained when using unconventional bearing systems, presented. Modeling and analysis of radial-flow and axial-flow microturbines a

  17. Numerical investigation of a straw combustion boiler – Part I: Modelling of the thermo-chemical conversion of straw

    Directory of Open Access Journals (Sweden)

    Dernbecher Andrea

    2016-01-01

    Full Text Available In the framework of a European project, a straw combustion boiler in conjunction with an organic Rankine cycle is developed. One objective of the project is the enhancement of the combustion chamber by numerical methods. A comprehensive simulation of the combustion chamber is prepared, which contains the necessary submodels for the thermo-chemical conversion of straw and for the homogeneous gas phase reactions. Part I introduces the modelling approach for the thermal decomposition of the biomass inside the fuel bed, whereas part II deals with the simulation of the gas phase reactions in the freeboard.

  18. More performance by means of enhancement of the efficiency of CHP plants. CHP operation of an ORC plant; Mehr Leistung durch Effizienzsteigerung von KWK-Anlagen. KWK-Betrieb einer ORC-Anlage

    Energy Technology Data Exchange (ETDEWEB)

    Greschner, Timm; Fink, Jochen; Stadelmaier, Fabian [Duerr Cyplan Ltd., Bietigheim-Bissingen (Germany)

    2013-07-15

    In November 2012, the biogas plant of Stadtwerke Gross-Gerau-Versorgungs-GmbH (GGV) was supplemented with an energy-efficient organic Rankine cycle system (ORC) from Duerr Cyplan Ltd. (Bietigheim-Bissingen, Federal Republic of Germany). The ORC technology enables the utilization of the exhaust heat from the combustion of the gas for the power generation. Hereby, the efficiency in the power generation is increased by about 8 % in Gross-Gerau. Furthermore, the existing energy recovery concept is improved by the CHP operation of the ORC system. With the experience from Gross-Gerau new business segments can be accessed by means of the ORC technology.

  19. A novel photovoltaic power system which uses a large area concentrator mirror

    Science.gov (United States)

    Arrison, Anne; Fatemi, Navid

    1987-01-01

    A preliminary analysis has been made of a novel photovoltaic power system concept. The system is composed of a small area, dense photovoltaic array, a large area solar concentrator, and a battery system for energy storage. The feasibility of such a system is assessed for space power applications. The orbital efficiency, specific power, mass, and area of the system are calculated under various conditions and compared with those for the organic Rankine cycle solar dynamic system proposed for Space Station. Near term and advanced large area concentrator photovoltaic systems not only compare favorably to solar dynamic systems in terms of performance but offer other benefits as well.

  20. Steam generation unit in a simple version of biomass based small cogeneration unit

    OpenAIRE

    Sornek Krzysztof; Filipowicz Mariusz; Szubel Mateusz; Bożek Estera; Izdebski Krzysztof

    2014-01-01

    The organic Rankine cycle (ORC) is a very promising process for the conversion of low or medium temperature heat to electricity in small and micro scale biomass powered systems. Classic ORC is analogous to Clausius–Rankine cycle in a steam power plant, but instead of water it uses low boiling, organic working fluids. Seeking energy and economical optimization of biomass-based ORC systems, we have proposed some modifications e.g. in low boiling fluid circuit construction. Due to the fact that ...

  1. Thermoeconomic Analysis of Hybrid Power Plant Concepts for Geothermal Combined Heat and Power Generation

    Directory of Open Access Journals (Sweden)

    Florian Heberle

    2014-07-01

    Full Text Available We present a thermo-economic analysis for a low-temperature Organic Rankine Cycle (ORC in a combined heat and power generation (CHP case. For the hybrid power plant, thermal energy input is provided by a geothermal resource coupled with the exhaust gases of a biogas engine. A comparison to alternative geothermal CHP concepts is performed by considering variable parameters like ORC working fluid, supply temperature of the heating network or geothermal water temperature. Second law efficiency as well as economic parameters show that hybrid power plants are more efficient compared to conventional CHP concepts or separate use of the energy sources.

  2. Kilowatt isotope power system. Phase II plan. Volume V. Safety, quality assurance and reliability

    Energy Technology Data Exchange (ETDEWEB)

    1978-03-15

    The development of a Kilowatt Isotope Power System (KIPS) was begun in 1975 for the purpose of satisfying the power requirements of satellites in the 1980's. The KIPS is a /sup 238/PuO/sub 2/-fueled organic Rankine cycle turbine power system to provide a design output of 500 to 2000 W. Included in this volume are: launch and flight safety considerations; quality assurance techniques and procedures to be followed through system fabrication, assembly and inspection; and the reliability program made up of reliability prediction analysis, failure mode analysis and criticality analysis. (LCL)

  3. Optimization of idealized ORC in domestic combined heat and power generation

    Science.gov (United States)

    Rybiński, Witold; Mikielewicz, Jarosław

    2013-09-01

    Organic Rankine cycle (ORC) is used, amongst the others, in geothermal facilities, in waste heat recovery or in domestic combined heat and power (CHP) generation. The paper presents optimization of an idealized ORC equivalent of the Carnot cycle with non-zero temperature difference in heat exchangers and with energy dissipation caused by the viscous fluid flow. In this analysis the amount of heat outgoing from the ORC is given. Such a case corresponds to the application of an ORC in domestic CHP. This assumption is different from the most of ORC models where the incoming amount of heat is given.

  4. Toluene stability Space Station Rankine power system

    Science.gov (United States)

    Havens, V. N.; Ragaller, D. R.; Sibert, L.; Miller, D.

    1987-01-01

    A dynamic test loop is designed to evaluate the thermal stability of an organic Rankine cycle working fluid, toluene, for potential application to the Space Station power conversion unit. Samples of the noncondensible gases and the liquid toluene were taken periodically during the 3410 hour test at 750 F peak temperature. The results obtained from the toluene stability loop verify that toluene degradation will not lead to a loss of performance over the 30-year Space Station mission life requirement. The identity of the degradation products and the low rates of formation were as expected from toluene capsule test data.

  5. Numerical Analysis of Integral Characteristics for the Condenser Setups of Independent Power-Supply Sources with the Closed-Looped Thermodynamic Cycle

    Directory of Open Access Journals (Sweden)

    Olga V. Vysokomornaya

    2015-01-01

    Full Text Available The mathematical model of heat and mass transfer processes with phase transition is developed. It allows analysis of integral characteristics for the condenser setup of independent power-supply plant with the organic Rankine cycle. Different kinds of organic liquids can be used as a coolant and working substance. The temperatures of the working liquid at the condenser outlet under different values of outside air temperature are determined. The comparative analysis of the utilization efficiency of different cooling systems and organic coolants is carried out.

  6. Numerical Analysis of Integral Characteristics for the Condenser Setups of Independent Power-Supply Sources with the Closed-Looped Thermodynamic Cycle

    Directory of Open Access Journals (Sweden)

    Vysokomorny Vladimir S.

    2016-01-01

    Full Text Available The mathematical model of heat and mass transfer processes with phase transition is developed. It allows analyzing of integral characteristics for the condenser setup of independent power-supply plant with the organic Rankine cycle. Different kinds of organic liquids can be used as a coolant and working substance. The temperatures of the working liquid at the condenser outlet under different values of outside air temperature are determined. The comparative analysis of the utilization efficiency of different cooling systems and organic coolants is carried out.

  7. Rural Electrification through Decentralized Concentrating Solar Power: Technological and Socio-Economic Aspects

    Directory of Open Access Journals (Sweden)

    Sylvain Quoilin

    2013-09-01

    Full Text Available This paper presents the development of small-scale solar Organic Rankine Cycles for rural electrification in remote areas of Lesotho. It is subdivided in two parts. The first part deals with the success conditions of decentralized rural electrification projects. Through a literature survey, relevant guiding principles and recommendations are formulated. The second part of the paper describes the proposed system, which is designed in agreement with the formulated recommendations. A framework for benchmarking the performance and cost of various micro-utility platforms and rural electrification distribution models is proposed.

  8. Improving the Environmental Sustainability of Flash Geothermal Power Plants—A Case Study

    Directory of Open Access Journals (Sweden)

    Lorenzo Bruscoli

    2015-11-01

    Full Text Available The sustainability of geothermal energy production is analyzed with reference to a production plant located in a specific area (Monte Amiata, Italy. Four solutions combining a flash power plant with an Organic Rankine Cycle in a hybrid configuration are analyzed in terms of production of electricity, exergy balance and emissions level (CO2, H2S, Hg. The different solutions correspond to increasing environmental performance, and for the most advanced case achieve near-zero emissions (complete reinjection of the natural resource, including incondensable gases. The results show that this can be achieved at the price of a progressive reduction of electrical productivity.

  9. INVESTIGATION OF DIFFERENT MODELS OF COMBINED PARALLEL FLASH BINARY CYCLES

    OpenAIRE

    A. Jafar Yazdi*

    2017-01-01

    The aim of this paper is a comparative study of the different geothermal power plant concepts, based on the energy and exergy analysis. The cycles studied in this paper are the combination of single and double flash power plants with two different ORC cycles as basic Organic Rankine Cycle (ORC), ORC with IHE, regenerative ORC and regenerative ORC with an IHE. The main gain due to using combined flash-binary power plants with various types of ORCs is to achieve optimum and efficient energy uti...

  10. Design and modeling of an advanced marine machinery system including waste heat recovery and removal of sulphur oxides

    DEFF Research Database (Denmark)

    Frimann Nielsen, Rasmus; Haglind, Fredrik; Larsen, Ulrik

    2014-01-01

    that an ORC placed after the conventional waste heat recovery system is able to extract the sulphuric acid from the exhaust gas, while at the same time increase the combined cycle thermal efficiency by 2.6%. The findings indicate that the technology has potential in marine applications regarding both energy...... the efficiency of machinery systems. The wet sulphuric acid process is an effective way of removing flue gas sulphur oxides from land-based coal-fired power plants. Moreover, organic Rankine cycles (ORC) are suitable for heat to power conversion for low temperature heat sources. This paper describes the design...

  11. ORC technology for waste-wood to energy conversion in the furniture manufacturing industry

    Directory of Open Access Journals (Sweden)

    Moro Riccardo

    2008-01-01

    Full Text Available Exploitation of low and medium temperature thermal sources, in particular those based on biomass combustion and on industrial residual heat recovery, has been increasingly investigated in the last decades, accordingly to the growing interest towards reduction in primary energy consumption and environmental issues. Organic Rankine cycle technology allows designing power plants that are less demanding in terms of auxiliaries, safety systems, maintenance and operating costs when compared to conventional water steam power plants. To support the preliminary technical and economic design of this kind of plants in different contexts, a simulation code of part load and off-design operation of an organic Rankine cycle unit for combined heat and power has been developed. In the paper, taking the real situation of a furniture manufacturing factory as a starting point, it is shown how all energy flows occurring all year long inside the combined heat and power plant, can be estimated on the basis of the thermal user duty time profile, the available biomass flow rate and the adopted operation strategy. This information is the basis in order to correctly evaluate the energetic, economic and environmental advantages of the proposed technical solution, with respect to a particular context, as it is shown in the concluding part of the paper.

  12. Comparison of Moving Boundary and Finite-Volume Heat Exchanger Models in the Modelica Language

    Directory of Open Access Journals (Sweden)

    Adriano Desideri

    2016-05-01

    Full Text Available When modeling low capacity energy systems, such as a small size (5–150 kWel organic Rankine cycle unit, the governing dynamics are mainly concentrated in the heat exchangers. As a consequence, the accuracy and simulation speed of the higher level system model mainly depend on the heat exchanger model formulation. In particular, the modeling of thermo-flow systems characterized by evaporation or condensation requires heat exchanger models capable of handling phase transitions. To this aim, the finite volume (FV and the moving boundary (MB approaches are the most widely used. The two models are developed and included in the open-source ThermoCycle Modelica library. In this contribution, a comparison between the two approaches is presented. An integrity and accuracy test is designed to evaluate the performance of the FV and MB models during transient conditions. In order to analyze how the two modeling approaches perform when integrated at a system level, two organic Rankine cycle (ORC system models are built using the FV and the MB evaporator model, and their responses are compared against experimental data collected on an 11 kWel ORC power unit. Additionally, the effect of the void fraction value in the MB evaporator model and of the number of control volumes (CVs in the FV one is investigated. The results allow drawing general guidelines for the development of heat exchanger dynamic models involving two-phase flows.

  13. Conceptual design of the Truscott brine lake solar-pond system, volume 1: Utility-independent scenario

    Science.gov (United States)

    1981-06-01

    A conceptual design was performed for a series of solar pond systems to provide pumping power for chloride control in the Red River Basin. In the chloride control project, briny waters are diverted so as not to pollute portable water. The diverted brine is stored in a dammed natural basin where, with the aid of natural evaporation, the brine is concentrated to the salinities required for the solar ponds. The brine is transferred to the ponds and injected at the proper levels to establish the gradients and storage layers. The solar ponds are to be located within the Truscott, Texas brine impoundment lake. Heat will be extracted from the ponds and used to drive organic Rankine-cycle turbine generators. The electricity produced will serve the pumping needs of the chloride control project, pump brine from the natural source to the evaporation ponds, pump concentrated brine from the evaporation ponds to the solar ponds, maintain the solar ponds, and supply all system parasitic loads. It was found that five solar ponds with eight organic Rankine-cycle turbine-generators would serve both the average and peaking power requirements of the pumping stations in the Truscott area as they come on-line.

  14. Experimental Analysis of Thermoelectric Heat Exchanger for Power Generation from Salinity Gradient Solar Pond Using Low-Grade Heat

    Science.gov (United States)

    Singh, Baljit; Baharin, Nuraida `Aadilia; Remeli, Muhammad Fairuz; Oberoi, Amandeep; Date, Abhijit; Akbarzadeh, Aliakbar

    2016-10-01

    Salinity gradient solar ponds act as an integrated thermal solar energy collector and storage system. The temperature difference between the upper convective zone and the lower convective zone of a salinity gradient solar pond can be in the range of 40-60°C. The temperature at the bottom of the pond can reach up to 90°C. Low-grade heat (solar ponds is currently converted into electricity by organic Rankine cycle engines. Thermoelectric generators can operate at very low temperature differences and can be a good candidate to replace organic Rankine cycle engines for power generation from salinity gradient solar ponds. The temperature difference in a solar pond can be used to power thermoelectric generators for electricity production. This paper presents an experimental investigation of a thermoelectric generators heat exchanger system designed to be powered by the hot water from the lower convective zone of a solar pond, and cold water from the upper convective zone of a solar pond. The results obtained have indicated significant prospects of such a system to generate power from low-grade heat for remote area power supply systems.

  15. Reliabilitätskriterien für die Messung der Lebersteifigkeit mittels Echtzeit-2D-Shearwave-Elastografie bei verschiedenen klinischen Szenarien der chronischen Lebererkrankung

    DEFF Research Database (Denmark)

    Thiele, M; Madsen, B S; Procopet, B;

    2016-01-01

    Purpose: Liver stiffness measurement by real-time 2-dimensional shear wave elastography (2D-SWE) lacks universal reliability criteria. We sought to assess whether previously published 2D-SWE reliability criteria for portal hypertension were applicable for the evaluation of liver fibrosis and cirr...

  16. Determination of strontium-isotopes using Hidex 300 SL with TDCR-Cerenkov-counting; Messung von Strontium-Isotopen im Hidex 300 SL mittels TDCR-Cerenkov-counting

    Energy Technology Data Exchange (ETDEWEB)

    Wisser, S. [FCI, Mainz (Germany); Oikari, T. [Hidex Oy, Turku (Finland); Frenzel, E.

    2014-01-20

    A new rapid method for the determination of Sr-89/Sr-90 has been introduced due to the advances in the LSC-Technology. By means of the TDCR-Technique (Triple-to-Double-Coincidence-Ratio) in combination with Cerenkov-Counting, the samples can be measured directly after the sample preparation without significant waiting times. The prompt availability of results allows the competent authorities and radiation protection experts a faster reaction after a nuclear incident. The TDCR-Technique can also be applied for the routine analysis of Sr-90/Y-90. This method is also suitable for the determination of Sr-90/Y-90 directly after the radiochemical sample preparation. On the first step, the activity of Y-90 has to be determined by TDCR-Cerenkov-Counting. After adding LSC-Cocktail, the sum of Sr-90 und Y-90 can then be determined by TDCR-LSC measurement. The results obtained so far are very promising. The counting efficiencies obtained with Hidex 300 SL for the TDCR-LSC-measurement of Sr-90 were above 97%. The counting efficiencies for Sr-89 and Y-90 by TDCR-Cerenkov-Counting were higher than 60%.

  17. Removal of ammonia from industial water via adsorption/ion exchange of natural clinoptilolite; Entfernung von Ammoniak aus industriellen Waessern mittels Adsorption/Ionenaustausch an natuerlichem Clinoptilolith

    Energy Technology Data Exchange (ETDEWEB)

    Hein, M.; Henkel, A. [PreussenElektra AG, Kraftwerk Staudinger, Grosskrotzenburg (Germany); Pflug, H. [PreussenElektra Engineering GmbH, Hannover (Germany)

    1999-05-01

    The procedure described is a combination of adsorption and cation exchange. Its advantages are the selectivity of ammonium anions and the insensibility to disturbances. In addition, the technical and financial expenditure is low. This procedure is especially suitable for industrial water with ammonia concentrations of less than 50 mg/l. In this case it has an advantage over the conventional thermal degassification which necessitates higher operating expenditure. It has an advantage also over biological nitrification. Operating experience with laboratory and industrial plants is being explained. (orig.) [Deutsch] Das vorgestellte Verfahren ist eine Kombination aus Adsorption und Kationenaustausch. Seine Vorteile liegen in der Selektivitaet fuer Ammonium-Anionen und der Stoerunempfindlichkeit. Weiterhin bedarf es nur eines geringen technischen und finanziellen Aufwands. Besonders vorteilhaft kann das Verfahren bei Abwaessern mit Ammonium-Konzentrationen von weniger als 50 mg/l eingesetzt werden. Hier hat es Vorteile gegenueber dem Verfahren der thermischen Strippung, das einen hoeheren Betriebskostenaufwand erfordert. Auch gegenueber biologischen Verfahren bietet das Verfahren Vorteile. Die Betriebserfahrungen mit den Labor- und Technikumsanlagen werden erlaeutert. (orig.)

  18. Hydraulic balance by means of electromotoric HKV drives for dynamic load profiles; Hydraulischer Abgleich mittels elektromotorischer HKV-Antriebe fuer dynamische Lastprofile

    Energy Technology Data Exchange (ETDEWEB)

    Szendrei, Danny [Westsaechsische Hochschule Zwickau (Germany)

    2010-07-01

    To date, measures and concepts for saving energy become more and more important. The development of prices for conventional energy sources forces public and private households and businesses to changes in consumer behaviour and purchasing behaviour. Due to the structural infrastructure, the housing construction in communes strongly is affected by these developments. Nearly 35 % of the total energy demand in Europe account for heating of buildings generally. The most common type of heating system for heating of residential buildings is the central hot water heating in the two-tube version. It is assumed that nearly 90 % of the operated plants have a hydraulic unbalance. Additionally, balanced heating systems fulfil the desired efficiency only under certain, structural design conditions. The integration of the control of heating systems in the smart home infrastructure or KNX infrastructure enables a building-independent, tunable heat supply between buildings and consumption acquisition. The hydraulic system loads can be optimized simultaneously via the direct access to the control value. Thus, a homogeneous mass distribution over the plant can be guaranteed which is derived from the dynamic needs of the system users. These heat loads are calculated by the KNX system and the application of HeatingControl.

  19. High temporal resolution measurement of the exhaust gas mass flow and temperature by means of ultrasound; Die hochaufloesende Messung von Abgasmassenstrom und -temperatur mittels Ultraschall

    Energy Technology Data Exchange (ETDEWEB)

    Klee, P. [Kaiserslautern Univ. (Germany). Arbeitsgruppe Verbrennungskraftmaschinen; Gebhardt, W. [Fraunhofer-Inst. fuer Zerstoerungsfreie Materialpruefung, Saarbruecken (Germany)

    1998-03-01

    Within this research project at the Fraunhofer-Institute for Non-Destructive Test Methods (IzfP Saarbruecken) an ultrasonic time measurement technique was devised for high temporal resolution measurement of exhaust gas mass flow and temperature. To make it suitable for everything from tailpipes to cylinder exhaust it was necessary first and foremost to develop high temperature resistant airborne ultrasonic sensors. The developed sensors and the water-cooled measurement assembly can be utilised up to an exhaust gas temperature of 600 C. An extension of the temperature range up to 1000 C has been dispensed with up to now in favour of solving turbulence and solid-borne sound problems. The sensors and the measurement method were tested at a motor test bench at the Chair of Internal Combustion Engines at the University of Kaiserslautern. The average values of exhaust gas flow and temperature were in good agreement with the values determined from fuel/air consumption. It was demonstrated that this technique can be used up to 6000 rpm. (orig.) [Deutsch] Die Ultraschall-Laufzeitmesstechnik wurde im Verlauf dieses Forschungsvorhabens durch das Fraunhofer-Institut fuer zerstoerungsfreie Pruefverfahren (IzfP), Saarbruecken, als Verfahren zur zeitlich hochaufgeloesten Erfassung von Abgasmassenstrom und -temperatur etabliert. Eine Eignung von Auspuffendrohr bis zur Naehe Zylinderauslass erforderte in erster Linie die Schaffung einer hochtemperaturresistenten Ultraschallsensorik. Die entwickelte Sensorik und die Messstrecke sind mit Wasserkuehlung bis zu 600 C Abgastemperatur einsetzbar. Auf eine Erweiterung des Temperaturbereiches in Richtung 1000 C wurde bisher zugunsten der Loesung der Turbulenz- und Koerperschallproblematik verzichtet. Die am Motorpruefstand des Lehrstuhls fuer Kraft- und Arbeitsmaschinen der Universitaet Kaiserslautern gemessenen, zeitlich hochaufgeloesten Massenstroeme stimmen in ihren zeitlichen Mittelwerten gut mit den aus Kraftstoff- und Luftdurchsatz errechneten Werten ueberein. Die Ultraschallmessstrecke liefert bis zu Drehzahlen von 6000/min gut auswertbare Signale. (orig.)

  20. Protektionismus vs. Liberalismus im landwirtschaftlichen Handel? Zollabgaben oder außertarifliche Mittel für den Marktschutz? Chancen und Entwicklungsgefahren des polnischen landwirtschaftlichen Sektors

    Directory of Open Access Journals (Sweden)

    Elżbieta Daszkowska

    2009-01-01

    Full Text Available An der Schwelle des 21. Jahrhunderts in einem Zeitalter der Dominanz der liberalen Ansichten über den Welthandel kann man immer häufiger die Situation beobachten, wenn entwickelte Staaten, die traditionell als Fürsprecher des uneingeschränkten Handelsaustausches gelten, immer häufiger nach außertariflichen Mitteln zum Schutz ihrer eigenen Märkte greifen. Ziel dieses Artikels ist ein Bestimmungsversuch, ob Zollabgaben weiterhin ein wirksames Werkzeug für den Marktschutz sind oder ob diese Bedeutung an außertarifliche Barrieren übergegangen ist. Außerdem wurde in dieser Bearbeitung das Thema der Aktualität des protektionistischen Standpunktes in Agrarfragen, die Polen seit Jahren vertritt, aufgegriffen und zwar im Hinblick auf Chancen und Entwicklungsgefahren dieses Wirtschaftssektors in der ersten Dekade des 21. Jahrhunderts.

  1. Advances in the staging of renal cell carcinoma with high-resolution imaging; Fortschritte im Staging des Nierenzellkarzinoms mittels hochaufloesender Bildgebung

    Energy Technology Data Exchange (ETDEWEB)

    Hallscheidt, P.; Noeldge, G.; Schawo, S.; Kauffmann, G.; Palmowski, M. [Abt. Radiodiagnostik, Radiologische Klinik, Univ. Heidelberg (Germany); Bartling, S. [Medizinische Physik, DKFZ Heidelberg (Germany); Pfitzenmaier, J. [Urologische Klinik, Univ. Heidelberg (Germany)

    2007-12-15

    Modern imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI) allow high-resolution imaging of the abdomen. Modern scanners made high temporal as well as high spatial resolution available. Therapeutic approaches to the treatment of renal cell carcinoma have been improved over the recent years. Besides conventional and open laparoscopic tumor nephrectomy and nephron sparing, surgical approaches such as local tumor cryotherapy and radiofrequency ablation (RF) are ablative modalities and are used increasingly. Improved anesthesiological methods and new surgical approaches also allow curative treatment in extended tumors. Prerequisites for preoperative imaging modalities include visualization of the kidney tumor as well as its staging. Tumor-related infiltration of the renal pelvis or invasion of the perinephric fat and the renal hilus has to be excluded prior to nephron sparing surgery. In cases with extended tumors with infiltration of the inferior vena cava, it is necessary to visualize the exact extension of the tumor growth towards the right atrium in the vena cava. The radiologist should be informed about the diagnostic possibilities and limitations of the imaging modalities of CT and MRI in order to support the urologist in the planning and performance of surgical therapeutical approaches. (orig.)

  2. Development of a high performance drivage by 'Bolter-Miner' technology; Entwicklung eines Hochleistungsvortriebs mittels Bolter-Miner-Technik

    Energy Technology Data Exchange (ETDEWEB)

    Vierhaus, R. [Deutsche Steinkohle AG, Herne (Germany); Terbach, G. [Bergwerk Auguste Victoria/Blumenthal, Marl (Germany)

    2002-09-05

    The introduction of the bolter miner technic at Auguste Victoria/Blumenthal mine will be shown. This benchmarking project coming from the australian mining industry was put into practice for the first time in the german hard coal industry. It was rapidly turned out, that the demands of the roadways concerning the number and length of the required bolts and as well as the safety aspects are very different to the visited headings in Australia. The way starting with an average drivage rate of 5 m/d day in the first project up to today's performance level of 16 m/d in the third project is represented. From a view on the totality it is described, what kind of demands are required by the logistics, the infrastructure, the organization of the operation, the ergonomics and last but not least the motivation of the crew to achieve a high performance of 22 m/d. (orig.) [German] Im Beitrag wird die Einfuehrung der Bolter-Miner-Technik auf dem Bergwerk Auguste Victoria/Blumenthal aufgezeigt. Dieses Benchmarking-Projekt aus dem australischen Bergbau wurde erstmalig im deutschen Steinkohlenbergbau umgesetzt. Es zeigte sich sehr schnell, dass die Anforderungen der Strecken in bezug auf die Anzahl und Laenge der einzubauenden Anker sowie die sicherheitlichen Aspekte zu den besuchten Vortrieben in Australien stark differierten. Zudem wird der Weg von durchschnittlich 5 m/d im ersten Projekt bis zu den heutigen Leistungsdaten von 16 m/d im dritten Projekt dargestellt. In einer ganzheitlichen Betrachtung wird aufgezeigt, welche Anforderungen in der Logistik, in der Infrastruktur, in der Betriebsorganisation, in der Ergonomie und in der Motivation der Mannschaft notwendig waren, Spitzenleistungen von 22 m/d zu erreichen. (orig.)

  3. Laboratory work for preparation of scraping tests of high-frequency welded pipes using electrodynamic, ultrasonic transducers. Laboruntersuchungen zur Schabungspruefung hochfrequenzgeschweisster Rohre mittels elektrodynamischer US-Wandler

    Energy Technology Data Exchange (ETDEWEB)

    Koch, R.; Maurer, A. (Nuklear-Chemie und -Metallurgie GmbH (NUKEM), Alzenau (Germany, F.R.))

    1990-01-01

    High-resolution examinations for which coupling agents cannot be used are done with dry-coupled, electrodynamic ultrasonic transducers. A specific electrodynamic transducer supported by an air cushion has been used for measuring the wall thickness curve directly behind a high-frequency weld seam. The paper presents wall thickness profiles in unwelded zones and in scraped zones. (DG).

  4. Detection of microbial volatile organic compounds (MVOC) by means of ion mobility spectroscopy (IMS); Detektion leicht fluechtiger organischer Verbindungen mikrobiellen Ursprungs (MVOC) mittels Ionenmobilitaetsspektrometrie (IMS)

    Energy Technology Data Exchange (ETDEWEB)

    Tiebe, Carlo

    2010-07-01

    Traces of microbial volatile organic compounds (MVOCs) can indicate the growth of moulds in the indoor air. The application of ion mobility spectrometry (IMS) is a very promising method for the detection of these MVOCs due to its high sensitivity. A mobile IMS device was tested to use this analytical-chemical method for in situ indoor air diagnostics. The first part of this work describes the test gas generation of 14 MVOCs in the laboratory. The test gases were produced by preparation of permeation procedures. Due to the MVOCs test gases IMS parameters like reduced mobility (K{sub 0}), relative drift time (t{sub rd}), the concentration dependency of MVOCs signals were determined and the limit of detection (LOD) was calculated. The LODs are in the range of 2 to 192 {mu}g m{sup -3} (1 to 51 ppb{sub V}). In the second part of this manuscript seven different mould species were cultivated on nutrient media and their MVOCs emissions were explored. It was found out, that the MVOCs emissions of moulds have a dependency of species and of their cultivation time. These results are confirmed by principal component analysis (PCA). The identification of these MVOCs was performed by test-related GC-MS analysis and approved these results. The MVOCs emissions were explored in the cultivation of mould mixtures on three different building materials. The IMS-results were interpreted chemo metrically by PCA. It was possible to find different emission patterns of cultivated moulds on building materials without an identification of the MVOCs inside the emission chamber. In 27 field trials of different indoor environments (rooms) the IMS was tested to detect MVOCs. In 59 % of the cases a positive correlation is determined between visible mould-infested rooms and the detected MVOCs by IMS. (orig.)

  5. Methodological study of aging effects on fuel cells using X-ray synchrotron radiography and tomography; Methodische Untersuchung von Alterungseffekten an Brennstoffzellen mittels Synchrotronradiografie und -tomografie

    Energy Technology Data Exchange (ETDEWEB)

    Arlt, Tobias

    2012-04-05

    In the present work, new and advanced methods for the investigation of methanol and hydrogen powered fuel cells were analyzed. Synchrotron radiography and tomography were applied to investigate materials and transport processes in operating fuel cells ''in-situ'' and non-destructively. The corrosion of ruthenium is a key issue during aging of direct methanol fuel cells (DMFC). Therefore the influence of different aging processes on the distribution of ruthenium is of great interesting. An imaging method based on X-ray absorption spectroscopy (XAS) was applied to investigate the changes in the distribution of fuel cell catalysts three-dimensionally. Using monoenergetic synchrotron radiation it was shown that the distribution of ruthenium (Ru) in the anode catalyst changes after application of an accelerated aging procedure. A strong influence on the flowfield and the gas diffusion layer structures on the Ru distribution were found in the gas diffusion electrode at the anode side. Additionally some ruthenium moves through the membrane from the anode to the cathode. The redistribution caused by the accelerated aging procedure strongly differs from that obtained after aging under realistic stack operation (here over 1700 h) of a fuel cell in a pallet transporter. For the tomographic investigations samples were taken out from a stack operation in aged membrane electrode assembly (MEA) and were analyzed ex-situ. It was shown that the Ru redistribution can be attributed to mass transport processes (CO{sub 2} and H{sub 2}O) in the gas diffusion layer (GDL). Other high energy resolved measurements showed that the strength of the oxidation of ruthenium and platinum depends on the spatial distribution of the ruthenium. Last mentioned - also for the platinum catalyst - could be given quantitatively by means of this newly developed method. In the second part of this work high temperature polymer electrolyte fuel cells (HT-PEFC) were investigated. No liquid water can be found due to the high operation temperature of 160-200 C in this cell type. Hence conventional analysis methods are not applicable here. In especial the product water is very important for the electrical conductivity of the membrane and changes the state of the phosphoric acid inside the membrane and the electrodes. For the first time, the water balance in a HT-PEFC at different operating conditions was characterized in-situ during cell operation. The characterization was based on measured changes in the membrane transmittance and its thickness. Suitable models allowed calculating the water balance of the membrane. The influence of different operating conditions on the redistribution of the phosphoric acid between the electrodes and in the membrane was analyzed. The analysis is complemented with investigations of polarization curve recording and electrochemical impedance spectroscopy.

  6. Using solar heat to enhance waste-heat use; Solarthermische Abwaermenutzung; Aufwertung von Abwaerme mittels Solarthermie zur Erzeugung hochwertiger Prozessenergie - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, R. [BMG Engineering AG, Schlieren (Switzerland); Luzzi, A.; Marty, H. [HSR, Hochschule fuer Technik, SPF Institut fuer Solartechnik, Rapperswil (Switzerland)

    2008-12-15

    This final report for Swiss Federal Office of Energy (SFOE) presents the work done in a project involving the use of solar heat to enhance the use of waste heat at a chemical plant in Nyon, Switzerland. On the basis of a study carried out in 2006/2007, which looked at the reduction of process energy demand of a production site where an agent is produced in batch operation, possibilities for the recovery of waste heat were identified. The relatively low temperatures of the existing waste heat flows have, however, complicated its efficient use. This reflects a problem with waste heat use in industrial processes that can often be observed. Due to the sunny location in Nyon, a concept using solar energy to increase the temperature level of this waste heat has been developed. The objective of this analysis was the technical and economical assessment of such an installation and its transferability to other sites. Variants are presented and their economic viability is discussed.

  7. Determination of the electromagnetic dipole strength distribution in medium-heavy atomic nuclei by means of nuclear resonance fluorescence; Bestimmung der elektromagnetischen Dipolstaerkeverteilung in mittelschweren Atomkernen mittels Kernresonanzfluoreszenz

    Energy Technology Data Exchange (ETDEWEB)

    Massarczyk, Ralph Jens

    2011-01-17

    During the last hundred years several models were developed to describe the configuration of nuclei. These models have to make predictions, which should be comparable with experiments. As a standard type of experiment the nuclear resonance fluorescence was established. A nucleus is excited by irradiation with photons. By emitting one or more photons the nucleus decays back to the ground state. With this method it is possible to measure energy levels and to determine the strength of their excitation. A continuum of unresolved peaks gives additional strength. The existing setup at the linear electron accelerator ELBE of the Forschungszentrum Dresden-Rossendorf uses bremsstrahlung, produced as a secondary beam in a thin Niobium foil. During the years 2008/09 experiments on the nuclei of {sup 86}Kr and {sup 136}Ba took place there. In this work they will be analyzed. Photon flux and efficiency determination have been done as well as simulations on detector response and non-nuclear scattered background events. For this purpose the GEANT4 package was used. Finally the resulting cross sections were corrected for branching and feeding.

  8. Manipulation of incoherent and coherent spin ensembles in diluted magnetic semiconductors via ferromagnetic fringe fields; Manipulation inkohaerenter und kohaerenter Spinensembles in verduennt-magnetischen Halbleitern mittels ferromagnetischer Streufelder

    Energy Technology Data Exchange (ETDEWEB)

    Halm, Simon

    2009-05-19

    In this thesis it is demonstrated that fringe fields of nanostructured ferromagnets provide the opportunity to manipulate both incoherent and coherent spin ensembles in a dilute magnetic semiconductor (DMS). Fringe fields of Fe/Tb ferromagnets with a remanent out-of-plane magnetization induce a local magnetization in a (Zn,Cd,Mn)Se DMS. Due to the sp-d exchange interaction, optically generated electron-hole pairs align their spin along the DMS magnetization. One obtains a local, remanent spin polarization which was probed by spatially resolved, polarization sensitive photoluminescence spectroscopy. Fringe fields from in-plane magnetized Co ferromagnets allow to locally modify the precession frequency of the Manganese magnetic moments of the DMS in an external magnetic field. This was probed by time-resolved Kerr rotation technique. The inhomogeneity of the fringe field leads to a shortening of the ensemble decoherence time and to the effect of a time-dependent ensemble precession frequency. (orig.)

  9. Innovative technologies for emitter formation of crystalline silicon solar cells using in-line diffusion; Innovative Technologien zur Emittererzeugung fuer kristalline Silizium-Solarzellen mittels Durchlaufdiffusion

    Energy Technology Data Exchange (ETDEWEB)

    Voyer, Catherine

    2009-04-20

    An in-line emitter formation process for crystalline silicon solar cells was developed. The wafers were coated at room temperature with dilute phosphoric acid (2.5 w/w% in water) using ultrasonic spraying and then heated up to temperatures around 900 C in a metal-contamination-free in-line furnace. In the first zones of the furnace, a phosphosilicate glass (PSG) is formed on the silicon surface and serves as the doping source. The PSG thickness was adjusted by varying the flow rate of dilute phosphoric acid to the spray nozzle and took on values appropriate for emitter formation, in the range of {proportional_to}40-120 nm. A surfactant mixture was added to the dilute phosphoric acid in order to obtain complete wetting of the silicon surface. The mixture, which was composed of a hydrocarbon surfactant and of a fluorosurfactant, achieved better wetting properties than would be possible when using only one of the two surfactants. The spray solution containing only the hydrocarbon surfactant achieved a faster drop flattening, while the spray solution containing only the fluorosurfactant achieved a lower static surface tension. The mixture allowed for a combination of these desired properties: The drops coalesced together sufficiently rapidly (before drying) on the silicon surface to form a complete dopant source liquid layer and this layer remains sufficiently homogeneous during the layer drying. The sprayed-on layer is thicker ({proportional_to}15 microns) than the height of the surface texture ({proportional_to}5-10 microns). The liquid strives for a state of equilibrium, a convex meniscus. The topography of the liquid surface at the time at which the increase in viscosity puts an end to the liquid flow is reflected in the topography of the PSG thickness. The corresponding variations in sheet resistance across a wafer are sufficiently small for solar cells. Furthermore, the liquid layer conforms itself, during the drying, to the surface texture on a microscopic scale, and thus the PSG thickness and the emitter essentially follow the surface texture, as seen on SEM pictures. Through dehydration of the phosphorus molecules and reaction with silicon, the layer turns into a PSG. This process produces a vapour which contains water and phosphorus compounds. A steeper heat-up curve or a higher vapour pressure leads to a thicker PSG. In this work, a high PSG thickness homogeneity was obtained through adjustment of the air supply in the furnace entrance area. It was furthermore shown that under the condition of a steep heat-up curve, the PSG formation is only completed at temperatures above 700 C. The influence of the furnace transport speed and plateau temperature and of the spray nozzle flow rate on the emitter doping profile was examined. A lower speed or a higher temperature resulted in a lower sheet resistance. Moreover, the emitter phosphorus surface concentration was increased or reduced through, respectively, an increase or a reduction of the spray nozzle flow rate. The dependence of sheet resistance on PSG thickness was found to show a non-monotonous behaviour: Sheet resistance first decreased with increasing PSG thickness, reached a minimum and then increased. The reduction is explained by the increasing amount of phosphorus available for diffusion into silicon. The increase is assumed to be due to the longer time and greater energy requirement for PSG formation from a thicker dopant source layer, which leads to a weaker phosphorus diffusion into silicon in the first zones of the furnace. A high homogeneity of sheet resistance was obtained, for example a relative standard deviation of 2.5% on a textured surface. Standard screen-printed Cz-Si solar cells were made which had high values of open-circuit voltage of up to 626 mV, of short-circuit current of up to 36 mA/cm{sup 2} and of efficiency of up to 17.5%. In addition, the doping profile was varied. Textured solar cells with in-line diffusion achieved an efficiency of up to 16.8% compared to 16.5% for the reference solar cells with tube furnace diffusion. High fill facto

  10. Influence of body constitution on bone mineral density measured by digital radiogrammetry; Einfluss der Koerperkonstitution auf die mittels digitaler Radiogrammetrie evaluierte Knochenmineraldichte

    Energy Technology Data Exchange (ETDEWEB)

    Boettcher, J.; Pfeil, A.; Petrovitch, A.; Kramer, A.; Mentzel, H.J.; Hansch, A.; Malich, A.; Kaiser, W.A. [Inst. fuer Diagnostische und Interventionelle Radiologie, Friedrich-Schiller-Univ. Jena (Germany); Teufl, F. [Klinik fuer Diagnostische Radiologie, Kreiskrankenhaus Stollberg (Germany); Lehmann, G.; Hein, G. [Klinik fuer Innere Medizin III, Abt. Rheumatologie und Osteologie, Friedrich-Schiller-Univ. Jena (Germany)

    2005-02-01

    Purpose: in addition to many established osteodensitometri-techniques, digital radiogrammetry (DXR) is considered to be a reliable method for measuring the cortical bone mineral density (DXR-BMD). This study investigates the influence of body constitution on BMD of healthy adults as calculated by DXR. Materials and methods: in a prospective study, 246 adults without bone affecting diseases in their clinical history underwent DXR for analysis and calculations of bone mineral density and determination of metacarpal index (MCI) and porosity index (PI). Height, weight and body mass index (BMI) were recorded for each patient. Results: for all individuals and for all BMI subgroups, both height (0.55

  11. Development of a portable, automated system for the separation of radionuclides by column chromatography; Entwicklung eines portablen, automatisierten Systems fuer die Trennung von Radionukliden mittels Saeulenchromatographie

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, C.; Burow, M.; Flucht, R.; Hill, P.; Zoriy, M.V. [Forschungszentrum Juelich GmbH, Juelich (Germany)

    2012-07-01

    The determination of the chemical recovery is one of the most important challenges in the radiochemical analysis. Small changes at the pH-value and temperature changes lead to uncontrollable conditions in process. To improve the reproducibility of the chemical determination a separate separating column system (TSM) was developed at the analytic laboratory at JUeLICH. Using the TSM it is possible to separate nuclides by applying variable eluents and ion exchangers also in samples with a very high salt content like urine. Up to now the methods are developed for the elements U, Am and Pu. The automation provides a bigger number of analysed samples per working day and a remarkable economy of time. Due to the increasing of the sample volume it is possible to improve the detection limit of overall analytical procedure (time needed for separation increases). Experimental parameters like rate of flow and chemical recovery were tested. In this progress it was tried to develop a dense portable system which is easy to use. This new TSM allows a realisation of various separating processes by the easy handling via laptop. (orig.)

  12. Smart Grid. Implementation of households by means of cross-linking and energy community; Smart Grid. Integration von Haushalten mittels Vernetzung und Energie-Community

    Energy Technology Data Exchange (ETDEWEB)

    Trick, U.; Steinheimer, M.; Ruhrig, P.; Toenjes, R. [Fachhochschule Frankfurt am Main (Germany); Hoelker, D. [Hochschule Osnabrueck (Germany)

    2012-07-01

    The problems arising from the increasingly volatile and decentralized power generation as well as the today's ''black box'' distribution networks are solved here by the introduction of a new concept of a peer-to-peer networked energy community. Based on the experience with communication value-added services a service management framework is introduced which allows on the one side personalized services for the smart home, especially the energy management, and includes the integration of multimedia communications. On the other side the concept provides a convenient networking of households, energy suppliers, distribution network operators and others with the objectives cost savings, avoidance of network expansion, energy saving, CO{sub 2}-reduction, etc. Initial simulations confirm the effectiveness of this new and powerful approach, most notably the benefits of battery storage in homes, but also the potential contributions of demand side integration (load shift). (orig.)

  13. Studies on layer growth and interfaces on Ta-base thin layers by means of XPS; Untersuchungen zu Schichtwachstum und Grenzflaechen an Ta-basierten Duennschichten mittels XPS

    Energy Technology Data Exchange (ETDEWEB)

    Zier, M.

    2007-11-02

    In this thesis studies on the growth and on the formation of the interfaces of Ta and TaN layers on Si and SiO{sub 2} were performed. In the system TaN on SiO{sub 2} no reaction on the interface could be found. As the system with the mostly disturbed interface Ta on SiO{sub 2} was proved. Here a reduction of the SiO{sub 2} at simultaneous oxidation of the Ta was to be observed. Additionally tantalum silicide was formed to be considered concerning the bonding state as Ta{sub 5}Si{sub 3}, from which a double layer of a tantalum silicide and a tantalum suboxide resulted. A whole thickness of the double layer of above 1 nm resulted. In the system Ta on Si at the deposition of the film on the interface a tantalum silicide was formed to be characterized concerning the bonding state as TaSi{sub 2}. The thickness of the interlayer growed thereby up to 0.8 nm in form of islands. Finally in the system TaN on Si a silicon nitride formation during the deposition was observed, which was attributed to the insertion of adsorbed nitrogen from the sputtering atmosphere by recoil implantation of the sputtered Ta atoms. The silicon nitride interlayer growed thereby up to a thickness of 0.8 nm.

  14. Interative planning using ctive planning using computer graphis - examples from the Rhenish lignite mining area; Interaktive Planung mittels graphischer Datenverarbeitung - Beispiele aus dem rheinischen Braunkohlerevier

    Energy Technology Data Exchange (ETDEWEB)

    Hartung, M. [Rheinbraun AG, Koeln (Germany)

    1995-03-01

    In the Rhenish mining area, the further development of the opencast mines is based on a long-term planning concept. Within the scope of medium- and short-term planning steps, the overall planning documents are prepared in detail by various technical sections. - Major part of the planning is based on three-dimensional graphic information. The use of computer graphics has allowed sequences to be optimized and thus rationalization measures to be taken. The system used at Rheinbraun is hardware and software made by the Intergraph company which - within the scope of pilot projects - proved their capability and economic efficiency. - In addition to the computer graphics-aided optimization of sequences within the technical sections, an efficient use calls for the various applications to be interlaced. Information and results are required and supplied on a mutual basis. At Rheinbraun, mining area-wide networking and standardization of open client-server systems created the necessary prerequisites of the special projects` efficient integration in the graphic and semi-graphic fields. - The tasks of be fulfilled by the individual applications range from basic applications such as maps, deposit processing and geohydrology via all steps and elements of opencast mine planning up to the support of planning and administration activities in the real estate and mining damage division. - To achieve the goal of integration - i.e. further streamlining by eliminating redundancies, avoiding intermediate steps and increasing accuracy -, the technical sections cooperate in an interdisciplinary, constructive and coordinated way. (orig.) [Deutsch] Im rheinischen Braunkohlenrevier wird zur Optimierung der bergmaennischen Planung die graphische Datenverarbeitung eingesetzt. Als Systembasis wird die Hard- und Software der Firma Intergraph genutzt. Durch revierweite Vernetzung und Standardisierung offener Client-Server-Systeme wurde die Voraussetzung zur wirksamen Integration von Fachprojekten im graphischen und teilgraphischen Bereich geschaffen. Anwendungen erfolgen bei der Risswerkerstellung, der Lagerstaettenbearbeitung, in der Geohydrologie sowie in allen Stufen und Komponenten der Tagebauplanung bis hin zur Planung und Verwaltung im Bereich von Liegenschaften und Bergschaeden. Mit der Einfuehrung der graphischen Datenverarbeitung konnten weitgehende Rationalisierungserfolge erzielt sowie die betrieblichen Ablaeufe verbessert werden. (orig.)

  15. Verification of the weak equivalence principle of supports and heavy masses using SQUIDs; Ueberpruefung des schwachen Aequivalenzprinzips von Traegern und schwerer Masse mittels Squids

    Energy Technology Data Exchange (ETDEWEB)

    Vodel, W.; Nietzsche, S.; Neubert, R. [Friedrich-Schiller-Universitaet Jena (Germany). Inst. fuer Festkoerperphysik; Dittus, H. [Univ. Bremen (Germany). Zentrum fuer angewandte Raumfahrttechnologie und Mikrogravitation

    2003-07-01

    The weak equivalence principle is one of the fundamental hypotheses of general relativity and one of the key elements of our physical picture of the world, but since Galileo there has been no satisfactory way of verifying it. The new SQUID technology may offer a solution. The contribution presents the experiments of Jena University. Applications are envisaged, e.g., in the STEP space mission of the NASA/ESA. [German] Das Schwache Aequivalenzprinzip ist eine der grundlegenden Hypothesen der Allgemeinen Relativitaetstheorie und damit einer der Grundpfeiler unseres physikalischen Weltbildes. Obwohl es seit den ersten Experimenten von Galileo Galilei am Schiefen Turm zu Pisa im Jahre 1638 bis heute schon zahlreiche und immer praeziser werdende Messungen zur Ueberpruefung der Aequivalenz von schwerer und traeger Masse gegeben hat, ist die strenge Gueltigkeit dieses fundamentalen Prinzips experimentell vergleichsweise unzureichend bestimmt. Neuere Methoden, wie der Einsatz SQUID-basierter Messtechnik und die Durchfuehrung von Experimenten auf Satelliten, lassen Verbesserungen schon in naher Zukunft erwarten, so dass theoretische Ueberlegungen zur Vereinigung aller uns bekannten physikalischen Wechselwirkungen, die eine Verletzung des Schwachen Aequivalenzprinzips voraussagen, experimentell eingegrenzt werden koennten. Der Beitrag gibt einen Ueberblick ueber die an der Universitaet Jena entwickelte SQUID-basierte Messtechnik zum Test des Aequivalenzprinzips und fasst die bisher bei Freifallversuchen am Fallturm Bremen erzielten experimentellen Ergebnisse zusammen. Ein Ausblick auf die geplante Raumfahrtmission STEP der NASA/ESA zum Praezisionstest des Schwachen Aequivalenzprinzips schliesst den Beitrag ab. (orig.)

  16. Pathological changes of the chemosensory function in multiple sclerosis. An MRI study; Pathologische Veraenderungen der Chemosensorik mittels Kernspintomografie bei Multipler Sklerose. Eine MRT-Studie

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, F.A.; Harms, L. [Charite Campus Mitte, Berlin (Germany). Dept. of Neurology - Consultation Service for Multiple Sclerosis; Fleiner, F.; Dahlslett, B.; Goektas, Oe. [Charite Campus Mitte, Berlin (Germany). Dept. of Otolaryngology, Head and Neck Surgery; Bohner, G.; Erb, K.; Luedemann, L. [Charite Campus Mitte, Berlin (Germany). Dept. of Radiology

    2011-06-15

    Purpose: To examine possible causes for olfactory and gustatory dysfunction in MS patients in a prospective study with MRI. Materials and Methods: 30 MS patients (21 women, 11 men, 22 - 65 years, diameter 42 years) were examined by MRI. The olfactory bulb (OB) and olfactory brain volume was correlated with the number and volume of MS lesions in the olfactory brain and the non-olfactory brain. Olfactory testing was performed using the Threshold-Discrimination-Identification Test (TDI), and gustatory function was tested using the Taste-Strips-Test (TST). Results: 33 % of the MS patients displayed olfactory dysfunction (8 % of the control group), and 17 % displayed gustatory dysfunction (5 % of the control group). There was a correlation between the olfactory brain volume and the number (r = -0.38, p < 0.05) and volume (r = -0.38, p < 0.05) of MS lesions in the olfactory brain. The olfactory brain volume correlated with the number of MS lesions in the non-olfactory brain (r = -0.48, p < 0.05). The volume of the left OB correlated with the volume of MS lesions in the olfactory brain (r = -0.42, p < 0.05), the number (r = 0.37, p < 0.05) and volume (r = 0.4, p < 0.05) of lesions in the left part of the olfactory brain and with the TST score (r = -0.45, p < 0.05). The TST score correlated with the volume of lesions in the left (r = -0.45, p < 0.05) and right part (r = -0.53, p < 0.05) of the olfactory brain. The TST score correlated with the number of lesions in the non-olfactory brain (r = -0.48, p < 0.05). Conclusion: The correlation between a higher number and volume of MS lesions in the olfactory brain with a decreased OB and olfactory brain volume could help to explain olfactory and gustatory dysfunction in MS patients. Just the left OB correlated with the number and volume of lesions in the olfactory brain. Manual segmentation was a suitable method for measuring OB and olfactory brain volume. (orig.)

  17. Functional estimation of kidneys after extracorporeal shock wave therapy (ESWL) by clearance. Funktionsbeurteilung der Nieren nach extrakorporaler Stosswellenlithotripsie (ESWL) mittels Nieren-Clearance

    Energy Technology Data Exchange (ETDEWEB)

    Sydow, K.; Kirschner, P.; Brien, G.; Buchali, K.; Frenzel, R. (Humboldt-Universitaet, Berlin (Germany). Medizinische Fakultaet)

    1991-10-01

    35 patients were scintiscanned with 99m-Tc-DTPA to determine the effects of extracorporeal shock waves used to desintegrate renal concrements may have on the patients renal function. The therapy was conducted using a standard Lithostar unit (Siemens) (20 patients) and an additional overtable module (15 patients). Functional scintigraphy was performed using a gamma camera before lithotripsy, and on the first day after it. Further control investigations were performed one or two weeks later and two till six months later. In both groups most of the patients developed temporary restrictions in renal function, some of them irreversible restrictions. Functional losses were found to be less severe with the use of the overtable module than with the standard Lithostar unit. (orig.).

  18. Land reclamation in the lignite open pit mining industry of Central and Eastern Europe - a comparative discourse; Rekultivierung im Braunkohlenbergbau Mittel- und Osteuropas - eine vergleichende Betrachtung

    Energy Technology Data Exchange (ETDEWEB)

    Drebenstedt, C. [TU Bergakademie, Freiberg (Germany)

    2003-03-01

    This comparative discourse on land reclamation in the Central and East European lignite mining regions is based on a complex analysis of the prevailing natural, geological, technological and social conditions. Considering the above conditions, the reclaimed land in the mined-out lignite mines of Central and Eastern Europe will predominantly be used as forests, although farming is also possible under particularly suitable conditions. Some of the land is given over to recreational purposes and integrated into the relevant landscape. Large lakes in residual holes of former lignite mines have only been created in Germany so far, where the special requirements of nature preservation have also been given attention. As regards the planning and financing regulations and the regulations coordinating the use of the post-mining land, there are differences between the individual countries which must be attributed to the rather diverse legal conditions. In general, the tasks associated with recultivation are defined similarly, are based on scientific investigations and are implemented at a very high level. The exchange of experience should be continued also in the future. (orig.)

  19. Qualitative Studie bei Patienten mit chronischen HWS-Schmerzen zu Effekten von Qigong und einem stabilisierenden Nackenübungsprogramm mittels semi-strukturierter Leitfadeninterviews

    OpenAIRE

    Farahani, Zubin

    2011-01-01

    The present study was nested ina randomized controlled study on the effects of Qigong and Exercise therapy for patients with chronic neck pain. The aim of our study was to understand possible areas for under consideration of the personal experience of the patients using semi-structured interviews as a qualitative research method. 10 Patients of the Qigong group and 10 patients of the Exercise Therapy group were selected randomly for the semi-structured interviews. The interview...

  20. Potent clones. Efficiency of phytoremediation by means of willow family on the status of heavy metals; Potente Klone. Wirkung der Phytoremediation mittels Weidengewaechsen auf den Schwermetallstatus

    Energy Technology Data Exchange (ETDEWEB)

    Fibian, Kurt D. [Rostock Univ. (Germany). Fachgebiet Pflanzenernaehrung; Gombler, Willy; Gruessing, Edgar; Janssen-Weets, Sybille; Schlaak, Michael [Fachhochschule Emden-Leer, Emden (Germany). Inst. fuer Umwelttechnik-EUTEC

    2010-11-15

    The contents of cadmium, copper and zinc in a polluted substrate (harbour silt) were determined by means of fractionated extraction. In a pot attempt, four willow clones were cultivated on this substrate. After a test period of three years the changes in the individual fractions of heavy metal were determined. At the same time, the remove capacity of the test pastures being relevant for the process of phytoextraction were determined by means of the content of heavy metals of the aboveground plant organs and its dry weight. The results show that two of the examined pasture clones clearly are better suitable than poplars and corn, in order to remove in particular cadmium and zinc from the soil by means of phytoremediation.

  1. Analysis of novel silicon and III-V solar cells by simulation and experiment; Analyse neuartiger Silizium- und III-V-Solarzellen mittels Simulation und Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Hermle, Martin

    2008-11-27

    This work presents various simulation studies of silicon and III-V solar cells. For standard silicon solar cells, one of the critical parameters to obtain good performance, is the rear side recombination velocity. The optical and electrical differences of the different cell structures were determined. The optical differences and the effective recombination velocity Sback of the different rear side structures for 1 Ohmcm material were extracted. Beside standard silicon solar cells, back junction silicon solar cells were investigated. Especially the influence of the front surface field and the electrical shading due to the rear side, was investigated. In the last two chapters, III-V solar cells were analysed. For the simulation of III-V multi-junction solar cells, the simulation of the tunneldiode is the basic prerequisite. In this work, the numerical calibration of an GaAs tunneldiode was achieved by using an non-local tunnel model. Using this model, it was possible to successfully simulate a III-V tandem solar cell. The last chapter deals with an optimization of the III-V 3-junction cell for space applications. Especially the influence of the GaAs middle cell was investigated. Due to structural changes, the end-of-life efficiency was drastically increased.

  2. Innovative technologies for emitter formation of crystalline silicon solar cells using in-line diffusion; Innovative Technologien zur Emittererzeugung fuer kristalline Silizium-Solarzellen mittels Durchlaufdiffusion

    Energy Technology Data Exchange (ETDEWEB)

    Voyer, Catherine

    2009-04-20

    An in-line emitter formation process for crystalline silicon solar cells was developed. The wafers were coated at room temperature with dilute phosphoric acid (2.5 w/w% in water) using ultrasonic spraying and then heated up to temperatures around 900 C in a metal-contamination-free in-line furnace. In the first zones of the furnace, a phosphosilicate glass (PSG) is formed on the silicon surface and serves as the doping source. The PSG thickness was adjusted by varying the flow rate of dilute phosphoric acid to the spray nozzle and took on values appropriate for emitter formation, in the range of {proportional_to}40-120 nm. A surfactant mixture was added to the dilute phosphoric acid in order to obtain complete wetting of the silicon surface. The mixture, which was composed of a hydrocarbon surfactant and of a fluorosurfactant, achieved better wetting properties than would be possible when using only one of the two surfactants. The spray solution containing only the hydrocarbon surfactant achieved a faster drop flattening, while the spray solution containing only the fluorosurfactant achieved a lower static surface tension. The mixture allowed for a combination of these desired properties: The drops coalesced together sufficiently rapidly (before drying) on the silicon surface to form a complete dopant source liquid layer and this layer remains sufficiently homogeneous during the layer drying. The sprayed-on layer is thicker ({proportional_to}15 microns) than the height of the surface texture ({proportional_to}5-10 microns). The liquid strives for a state of equilibrium, a convex meniscus. The topography of the liquid surface at the time at which the increase in viscosity puts an end to the liquid flow is reflected in the topography of the PSG thickness. The corresponding variations in sheet resistance across a wafer are sufficiently small for solar cells. Furthermore, the liquid layer conforms itself, during the drying, to the surface texture on a microscopic scale, and thus the PSG thickness and the emitter essentially follow the surface texture, as seen on SEM pictures. Through dehydration of the phosphorus molecules and reaction with silicon, the layer turns into a PSG. This process produces a vapour which contains water and phosphorus compounds. A steeper heat-up curve or a higher vapour pressure leads to a thicker PSG. In this work, a high PSG thickness homogeneity was obtained through adjustment of the air supply in the furnace entrance area. It was furthermore shown that under the condition of a steep heat-up curve, the PSG formation is only completed at temperatures above 700 C. The influence of the furnace transport speed and plateau temperature and of the spray nozzle flow rate on the emitter doping profile was examined. A lower speed or a higher temperature resulted in a lower sheet resistance. Moreover, the emitter phosphorus surface concentration was increased or reduced through, respectively, an increase or a reduction of the spray nozzle flow rate. The dependence of sheet resistance on PSG thickness was found to show a non-monotonous behaviour: Sheet resistance first decreased with increasing PSG thickness, reached a minimum and then increased. The reduction is explained by the increasing amount of phosphorus available for diffusion into silicon. The increase is assumed to be due to the longer time and greater energy requirement for PSG formation from a thicker dopant source layer, which leads to a weaker phosphorus diffusion into silicon in the first zones of the furnace. A high homogeneity of sheet resistance was obtained, for example a relative standard deviation of 2.5% on a textured surface. Standard screen-printed Cz-Si solar cells were made which had high values of open-circuit voltage of up to 626 mV, of short-circuit current of up to 36 mA/cm{sup 2} and of efficiency of up to 17.5%. In addition, the doping profile was varied. Textured solar cells with in-line diffusion achieved an efficiency of up to 16.8% compared to 16.5% for the reference solar cells with tube furnace diffusion. High fill facto

  3. Sentinel node detection by preoperative lymphoscintigraphy and intraoperative gamma-probe guidance in melanoma; Nachweis des Sentinel-Lymphknotens mittels praeoperativer Lymphszintigraphie und intraoperativer Gammasondenmessung bei malignen Melanom

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, H.; Wengenmair, H.; Dorn, R.; Heidenreich, P. [Zentralklinikum Augsburg (Germany). Klinik fuer Nuklearmedizin; Bachter, D. [Zentralklinikum Augsburg (Germany). Klinik fuer Dermatologie und Allergologie; Buechels, H.K. [Zentralklinikum Augsburg (Germany). Klinik fuer Allgemein- und Visceralchirurgie

    1999-08-01

    Aim: The purpose of this work was to prove the clinical significance of nuclear medical procedures in pre-and intraoperative detection of the SLN. Methods: In the past 4 years, we did preoperative lymphoscintigraphy in 214 patients (pts.). Intraoperative localisation of the SLN with a handheld gamma probe followed in 150 pts. Results: In 214 pts. 247 lymphatic draining regions were found by preoperative scintigraphy. In 3 pts. with melanoma of the cheek no lymphatics/lymphe nodes could be detected. 14 pts. showed interval lymph nodes. In 150 pts. gamma probe guided SLNE was done. In 2 pts. with supraclavicular primary tumor 4 SLN had been defined by preoperative scintigraphy but only 2 could be found intraoperatively. In all other cases (98.7%) the sentinel node was detected correctly by the gamma probe and then removed. In 19 of 150 pts. (12.7%) metastases were detected in the pathologic specimen. The incidence of lymph node metastases showed a continuous increase from 0% at tumor stage pT1 to 44% at stage pT4. Conclusion: SLNE is an accurate method to determine nodal involvement in melanoma and minimizes operative invasiveness in melanoma surgery. (orig.) [Deutsch] Ziel der vorliegenden Arbeit ist die Ueberpruefung der Wertigkeit nuklearmedizinischer Verfahren in der prae- und intraoperativen Diagnostik des Sentinel-Lymphknotens (SLN). Methoden: Bei 214 Patienten fuehrten wir waehrend der vergangenen vier Jahre die praeoperative Lymphszintigraphie und bei 150 Patienten die intraoperative Gammasondenmessung zur Lokalisationsdiagnostik des SLN durch. Ergebnisse: Es fanden sich bei 214 Patienten 247 Abflussgebiete. Bei drei Patienten konnte kein Lymphabfluss nachgewiesen werden. Es handelte sich um Melanome der Wange, zwei dieser Patienten waren voroperiert. 14 Patienten zeigten Intervall-Lymphknoten. Bei 150 Patienten erfolgte eine operative Entfernung des SLN (Sentinel-Lymphonodektomie, SLNE) mit intraoperativer Gammasondenmessung. Bei zwei Patienten mit supraklavikulaerem Primaertumor waren vier SLN praeoperativ festgelegt worden, von denen intraoperativ nur zwei gefunden wurden. In allen anderen Faellen konnte der SLN intraoperativ entdeckt und entfernt werden. Bei 19 der 150 Patienten (12,7%) wurden Metastasen in einem SLN nachgewiesen. Die Haeufigkeit der Metastasierung nahm von 0% im Stadium pT1 kontinuierlich bis 44% im Stadium pT4 zu. Schlussfolgerung: Die Lymphszintigraphie und Gammasondenmessung sind geeignete Verfahren fuer die Lokalisation des SLN. Die SLNE ist eine zuverlaessige Methode, um eine Lymphknotenbeteiligung bei malignem Melanom nachzuweisen. Sie minimiert den operativen Eingriff. (orig.)

  4. Growth of gallium nitride based devices on silicon(001) substrates by metalorganic vapor phase epitaxy; Wachstum von Galliumnitrid-basierten Bauelementen auf Silizium(001)-Substraten mittels metallorganischer Gasphasenepitaxie

    Energy Technology Data Exchange (ETDEWEB)

    Reiher, Fabian

    2009-02-25

    The main topic of this thesis is to investigate GaN-based layer systems grown by metalorganic vapor phase epitaxy on Si(001) substrates. A temperature shift up to 45 K is measured for a complete device structure on a 2-inch silicon substrate. By using a 40 nm thin LT-AlN-seed layer (680 C), the GaN crystallites on Si(001) substrates are almost oriented with their GaN(10 anti 12)-planes parallel to the Si(001)-plane. A four-fold azimuthal symmetry occurs for these layers, with the GaN[10 anti 11]-direction is aligned parallel to one of the four equivalent left angle 110 right angle -directions, respectively. However, a mono-crystalline and fully coalesced GaN-layer with this crystallographic orientation could not yet been obtained. If a deposition temperature of more than 1100 C is used for the AlN-seed layer, solely the GaN[0001]- growth direction of crystallites occurs in the main GaN layer on Si(001) substrates. These c-axis oriented GaN columns feature two opposite azimuthal alignments that are rotated by 90 with respect to each other and with GaN[11 anti 20] parallel Si[110] and GaN[10 anti 10] parallel Si[110], respectively. By using 4 off-oriented substrates towards the Si[110]-direction, one certain azimuthal texture component can be selected. The critical value of the miscut angle corresponds to theoretical calculations predicting the occurrence of atomic double steps on the Si(001) surface. The achieved crystallographic quality of the GaN layers on Si(001) is characterized by having a tilt of FWHM=0.27 and a twist of FWHM=0.8 of the crystallites, determined by X-ray diffraction. A completely crack-free, up to 2.5 {mu}m thick, and mono-crystalline GaN-template can be realized on Si(001), integrating 4 or 5 LT-AlN-interlayers in the GaN buffer structure. Based on this structure, the first successful implementation of an (InGaN/GaN)-LED on Si(001) is achieved. Furthermore, the possible fabrication of GaN-based FET-structures is demonstrated with a fully processed and operating device on Si(001). Moreover, the developed approach for the MOVPE growth of GaN on Si(001) is successfully adapted to large area 150 mm Si(001) substrates, proving the possible scalability to industrial circuits. (orig.)

  5. Plant documentation by means of a geographical information system - GIS at Bayerngas GmbH; Anlagendokumentation mittels eines Geographischen Informationssystems - GIS bei der Bayerngas GmbH

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, D. [PHOTOGRAMMETRIE GMBH, Muenchen (Germany); Schroecker, D.; Grosshennig, P. [Bayerngas GmbH, Muenchen (Germany)

    1998-11-01

    The report presents the gradual introduction of a geographical orientated information system using SMALLWORLD GIS for the documentation of the complete technical installations of Bayerngas. There is also a supplement description of the SMALLWORLD GIS, in particular the consideration of specific data of Bavarian geodesy. (orig.) [Deutsch] Im Bericht wird die phasenweise Einfuehrung eines geographisch orientierten Informationssystems unter Nutzung des SMALLWORLD GIS dargestellt, in dem alle technischen Anlagen bei der Bayerngas dokumentiert werden sollen. Es werden darueber hinaus Ergaenzungen zum SMALLWORLD GIS beschrieben, u.a. die Beruecksichtigung der bayernspezifischen Daten im Vermessungswesen. (orig.)

  6. Trace analysis of actinides in the environment using resonance ionization mass spectrometry; Spurenanalyse von Aktiniden in der Umwelt mittels Resonanzionisations-Massenspektrometrie

    Energy Technology Data Exchange (ETDEWEB)

    Raeder, Sebastian

    2011-04-12

    In this work the resonant ionization of neutral atoms using laser radiation was applied and optimized for ultra-trace analysis of the actinides thorium, uranium, neptunium and plutonium. The sensitive detection of these actinides is a challange for the monitoring and quantification of radioactive releases from nuclear facilities. Using resonance ionization spectroscopy combined with a newly developed quadrupole-mass-spectrometer, numerous energy levels in the atomic structure of these actinides could be identified. With this knowledge efficient excitation schemes for the mentioned actinides could be identified and characterised. The applied in-source-ionization ensures for a high detection efficiency due to the good overlap of laser radiation with the atomic beam and allows therefore for a low sample consumption which is required for the analysis of radio nuclides. The selective excitation processes in the resonant ionization method supresses unwanted contaminations and was optimized for analytical detection of ultra-trace amounts in environmental samples as well as for determination of isotopic compositions. The efficient in-source-ionization combined with high power pulsed laser radiation allows for detections efficiency up to 1%. For plutonium detection limits in the range of 10{sup 4}-10{sup 5} atoms could be demonstrated for synthetic samples as well as for first environmental samples. The usage of narrow bandwidth continuous wave lasers in combination with a transversal overlap of the laser radiation and the free propagating atomic beam enable for resolving individual isotopic shifts of the resonant transitions. This results in a high selectivity against dominant neighboring isotopes but with a significant loss in detection efficiency. For the ultra-trace isotope {sup 236}U a detection limit down to 10{sup -9} for the isotope ratio N ({sup 236}U)/N ({sup 238}U) could be determined.

  7. Effectiv process management at the municipal utility Wismar using a central control system; Effektives Prozessmanagement mittels zentraler Leittechnik bei den Stadtwerken Wismar

    Energy Technology Data Exchange (ETDEWEB)

    Niemann, F.; Schutt, M. [Stadtwerke Wismar GmbH (Germany); Schonert, W. [Ing.-Buero Fichtner, Stuttgart (Germany)

    1998-08-01

    The Wismar GmbH is a municipal energy supplier with many correspondent sections. It is responsible for the gas-, water- and heat-supply of Wismar city, which has about 52,000 residents. In order to be able to control the supply sections and to optimize the processes, a central control system was realized for sections gas, water and heat. The following problems have to been solved: - optimization of the gas supply and purchase, - controlling the heat supply from the generation until the customers station, - controlling the water supply, - increasing supply security by untimely trouble recognizing, - Automatic documentation and visualization of analog and digital inputs (i.e. measuring, meter reading, alarms and reports), - personal savings through reducing the 24-hours shift. (orig.) [Deutsch] Bildschirmorientierte Informations-, Bedien- und Beobachtungssysteme sind eine Grundvoraussetzung fuer die zuverlaessige und wirtschaftliche Ver- und Entsorgung. In dem folgenden Beitrag werden die Anforderungen an ein Leitsystem und die daraus resultierenden Strukturen aus der Sicht eines Betreibers und unter Beruecksichtigung der Waermeversorgung beschrieben. (orig.)

  8. Quantitative imaging of magnetic nanoparticles by magneto-relaxometric tomography for biomedical applications; Quantitative Bildgebung magnetischer Nanopartikel mittels magnetrelaxometrischer Tomographie fuer biomedizinische Anwendungen

    Energy Technology Data Exchange (ETDEWEB)

    Liebl, Maik

    2016-11-18

    Current biomedical research focuses on the development of novel biomedical applications based on magnetic nanoparticles (MNPs), e.g. for local cancer treatment. These therapy approaches employ MNPs as remotely controlled drug carriers or local heat generators. Since location and quantity of MNPs determine drug enrichment and heat production, quantitative knowledge of the MNP distribution inside a body is essential for the development and success of these therapies. Magnetorelaxometry (MRX) is capable to provide such quantitative information based on the specific response of the MNPs after switching-off an applied magnetic field. Applying a uniform (homogeneous) magnetic field to a MNP distribution and measuring the MNP response by multiple sensors at different locations allows for spatially resolved MNP quantification. However, to reconstruct the MNP distribution from this spatially resolved MRX data, an ill posed inverse problem has to be solved. So far, the solution of this problem was stabilized incorporating a-priori knowledge in the forward model, e.g. by setting priors on the vertical position of the distribution using a 2D reconstruction grid or setting priors on the number and geometry of the MNP sources inside the body. MRX tomography represents a novel approach for quantitative 3D imaging of MNPs, where the inverse solution is stabilized by a series of MRX measurements. In MRX tomography, only parts of the MNP distribution are sequentially magnetized by the use of inhomogeneous magnetic fields. Each magnetizing is followed by detection of the response of the corresponding part of the distribution by multiple sensors. The 3D reconstruction of the MNP distribution is then accomplished by a common evaluation of the distinct MRX measurement series. In this thesis the first experimental setup for MRX tomography was developed for quantitative 3D imaging of biomedical MNP distributions. It is based on a multi-channel magnetizing unit which has been engineered to generate a time-multiplexed sequence of precise magnetic fields for spatially constrained magnetizing of the MNP distribution. The unit has been integrated into a sensor system containing 304 superconducting quantum interference devices (SQUIDs) used for the spatially resolved detection of the MNP responses after each magnetizing. Furthermore, for evaluation of MRX tomography MNP phantoms reflecting the MNP distribution after magnetic drug targeting therapy in animals were designed and implemented. Using these phantoms, MNP distributions with clinical MNP doses in the milligram range could be quantitatively reconstructed by MRX tomography within a field of view up to 600 cm³ and a spatial resolution of a few cubic centimeters. The deviation between the quantified and nominal MNP amount was found to be below 10%. With the present experimental setup MRX tomography measurements of a complete MNP distribution were performed within the typical anesthesia time interval of a few minutes prevailing in preclinical animal studies. By implementing advanced magnetizing sequences this measurement time of the MRX tomography setup could be reduced to below 30 s. Finally, using the same MRX tomography setup a binding state specific quantitative imaging of MNP distributions was achieved by incorporating the temporal MNP relaxation behavior into the reconstruction. Hence, MRX tomography has the potential to image the influence of the local biological environment on the physical properties of the MNPs. The presented MRX tomography setup allows for sensitive and specific spatially resolved 3D quantification of MNPs in small animals. This represents an important step towards the development of a clinical imaging tool for the control and assessment of MNP based cancer treatments. Moreover, by adjusting the excitation coils the field of view could be easily enlarged making MRX tomography quite conceivable for human application.

  9. Investigation on a new agent for the prophylaxis and deletion of endogenous fires; Erforschung eines neuen Mittels zur Prophylaxe und Loeschen von endogenen Braenden

    Energy Technology Data Exchange (ETDEWEB)

    Michailov, Michail; Krilchev, Alexander; Vladkova, Blagovesta [Univ. fuer Bergbau und Geologie (Bulgaria). Lehrstuhl fuer Bergbaulueftung und Arbeitssicherheit; Dimova, Biljana [Technische Univ. Sofia (Bulgaria). Festigkeitslehre

    2011-03-15

    The actual development of the industry requires a greater demand for raw materials for the production, processing, transport and storage of various materials. This is associated with an increased risk to the occupational safety. One of the factors that influence the occupational safety, is the endogenous risk of fire of raw materials. The self-ignition of various materials can lead to huge property damages, threats and human sacrifices. The various technological schemes of raw material extraction, processing and transportation are associated with the elimination of large amounts of dust. The causes of dust explosions is the development of an endogenous fire. According to unofficial data annually about 50 dust explosions occur. Many of those do not result in detonations. There are no casualties or major property damage during some explosions. Consequently, these dust explosions are not declared. In order to avoid self-heating and subsequent spontaneous combustion, it is necessary to know the dangerous fire and explosion hazards of the materials used. Based on the investigation of various properties and the results obtained, appropriate measures are taken to reduce the risk of dust explosions. With this aim, the authors of this contribution under consideration have explored the behaviour of a new super-absorber for the prophylaxis and extinguishing of endogenous fires. The aim of the application of superabsorbent polymers is the limitation of conditions that promote a self-ignition and the creation of conditions that stop the already existing fire.

  10. Electrochemical dehalogenation of chlorinated aromatic hydrocarbons with nickel(II) complexes as mediators in methanol; Elektrochemische Enthalogenierung chlorierter Aromaten mittels Nickel(II)-Komplexen als Mediatoren in Methanol

    Energy Technology Data Exchange (ETDEWEB)

    Nuennecke, D.

    2000-07-01

    The dissertation investigates the electrochemical dechlorination of persistent organic chlorine compounds. An alternative to high-temperature combustion will be developed. The electrochemical dehalogenation reaction was to be made more selective with the aid of so-called mediator substances. A flow cell model was developed for continuous electrolytic cells. [German] Die vorliegende Arbeit beschaeftigt sich mit der elektrochemischen Dechlorierung von persistenten chlororganischen Verbindungen. Es soll eine Alternative zur Hochtemperatureverbrennung erarbeitet werden. Aufgabenstellung der Arbeit war die Erhoehung der Selektivitaet der elektrochemischen Enthalogenierung mithilfe von sog. Mediatoren. Fuer kontinuierlich arbeitenden Elektrolysezellen wurde ein Modell fuer eine Durchflusszelle entwickelt.(uke)

  11. Sentinel node detection by preoperative lymphoscintigraphy and intraoperative gamma-probe guidance in melanoma; Nachweis des Sentinel-Lymphknotens mittels praeoperativer Lymphszintigraphie und intraoperativer Gammasondenmessung bei malignen Melanom

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, H.; Wengenmair, H.; Dorn, R.; Heidenreich, P. [Zentralklinikum Augsburg (Germany). Klinik fuer Nuklearmedizin; Bachter, D. [Zentralklinikum Augsburg (Germany). Klinik fuer Dermatologie und Allergologie; Buechels, H.K. [Zentralklinikum Augsburg (Germany). Klinik fuer Allgemein- und Visceralchirurgie

    1999-08-01

    Aim: The purpose of this work was to prove the clinical significance of nuclear medical procedures in pre-and intraoperative detection of the SLN. Methods: In the past 4 years, we did preoperative lymphoscintigraphy in 214 patients (pts.). Intraoperative localisation of the SLN with a handheld gamma probe followed in 150 pts. Results: In 214 pts. 247 lymphatic draining regions were found by preoperative scintigraphy. In 3 pts. with melanoma of the cheek no lymphatics/lymphe nodes could be detected. 14 pts. showed interval lymph nodes. In 150 pts. gamma probe guided SLNE was done. In 2 pts. with supraclavicular primary tumor 4 SLN had been defined by preoperative scintigraphy but only 2 could be found intraoperatively. In all other cases (98.7%) the sentinel node was detected correctly by the gamma probe and then removed. In 19 of 150 pts. (12.7%) metastases were detected in the pathologic specimen. The incidence of lymph node metastases showed a continuous increase from 0% at tumor stage pT1 to 44% at stage pT4. Conclusion: SLNE is an accurate method to determine nodal involvement in melanoma and minimizes operative invasiveness in melanoma surgery. (orig.) [Deutsch] Ziel der vorliegenden Arbeit ist die Ueberpruefung der Wertigkeit nuklearmedizinischer Verfahren in der prae- und intraoperativen Diagnostik des Sentinel-Lymphknotens (SLN). Methoden: Bei 214 Patienten fuehrten wir waehrend der vergangenen vier Jahre die praeoperative Lymphszintigraphie und bei 150 Patienten die intraoperative Gammasondenmessung zur Lokalisationsdiagnostik des SLN durch. Ergebnisse: Es fanden sich bei 214 Patienten 247 Abflussgebiete. Bei drei Patienten konnte kein Lymphabfluss nachgewiesen werden. Es handelte sich um Melanome der Wange, zwei dieser Patienten waren voroperiert. 14 Patienten zeigten Intervall-Lymphknoten. Bei 150 Patienten erfolgte eine operative Entfernung des SLN (Sentinel-Lymphonodektomie, SLNE) mit intraoperativer Gammasondenmessung. Bei zwei Patienten mit supraklavikulaerem Primaertumor waren vier SLN praeoperativ festgelegt worden, von denen intraoperativ nur zwei gefunden wurden. In allen anderen Faellen konnte der SLN intraoperativ entdeckt und entfernt werden. Bei 19 der 150 Patienten (12,7%) wurden Metastasen in einem SLN nachgewiesen. Die Haeufigkeit der Metastasierung nahm von 0% im Stadium pT1 kontinuierlich bis 44% im Stadium pT4 zu. Schlussfolgerung: Die Lymphszintigraphie und Gammasondenmessung sind geeignete Verfahren fuer die Lokalisation des SLN. Die SLNE ist eine zuverlaessige Methode, um eine Lymphknotenbeteiligung bei malignem Melanom nachzuweisen. Sie minimiert den operativen Eingriff. (orig.)

  12. Characterization of oxidation protection coatings for high temperature applications by means of nanoindentation and scanning electron microscopy methods; Charakterisierung von Oxidationsschutzschichten fuer Hochtemperaturanwendungen mittels Nanoindentierung und rasterelektronenmikroskopischen Methoden

    Energy Technology Data Exchange (ETDEWEB)

    Webler, R.; Neumeier, S.; Goeken, M. [Erlangen-Nuernberg Univ., Erlangen (Germany). Lehrstuhl fuer Allgemeine Werkstoffeigenschaften

    2014-10-01

    Oxidation protection coatings are required for thermally highly stressed components such as turbine blades in aircraft engines. Cyclic oxidation experiments were performed on a NiCoCrAlY protective coating of a nickel-based superalloy and hardness and modulus of elasticity (mechanical properties) were determined by nanoindentation before and after the experiments. Microstructure and chemical composition were characterized by means of scanning electron microscopy. Here, the focus is on the phase identification by combining electron backscatter diffraction and energy dispersive X-ray spectroscopy. Findings indicate that the chemical composition strongly influences the mechanical properties.

  13. Measurement of transvers spin effects by means of two-hadron correlations in the COMPASS experiment; Messung transversaler Spineffekte mittels zwei Hadronen Korrelation am COMPASS-Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Massmann, Frank Michael

    2008-06-23

    The quark structure of the nucleon can at neglection of intrinsic quark transverse momenta be completely described by two quark distribution functions. These are the unpolarized quark distribution function q(x), the helicity distribution function {delta}q(x), and the transvers quark-spin distribution function {delta}{sub T}q(x). This lastly mentioned function called transversity function, is chirallyn odd an can therefore only be measured in a combination with another chirally odd function. An access possibility to the transversity function {delta}{sub T}q(x) is the semi-inclusive two-hadron production in deep inelastic scattering on a transversely polarized target. Thereby the folding of the chirally odd two-hadron interference fragmentation function (IFF) H{sub 1} {sup angle} (z,M{sub h}{sup 2}) and the chirally odd transversity function. The IFF H{sub 1} {sup angle} (z,M{sub h}{sup 2}) is the spin-dependent part of a fragmentation function, which describes the fragmentation of a transversely polarized quark in two unpolarized hadrons. The production of the two hadrons pursues in an interference between different wave-state of the hadron pairs. Azimuthal asymmetries in the produced hadron pairs are measured. The measurements, which are described in this thesis, were performed in the COMPASS experiment at CERN in the years 2002-2004, which is a solid-state-target experiment at the SPS accelerator. After an introduction in chapter 2 the basing theoretical concepts for the measurement of the transversity function are presented. In chapter 3 the COMPASS experiment is described. Finally in chapter 4 the evaluation methods are discussed, the results of the azimuthal asymmetries shown and compared with theoretical predictions. [German] Die Quark-Struktur des Nukleons laesst sich bei Vernachlaessigung intrinsischer Quarktransversalimpulse vollstaendig durch drei Quark Verteilungsfunktionen beschreiben. Diese sind die unpolarisierte Quark Verteilungsfunktion q(x), die Helizitaets- Verteilungsfunktion {delta}q(x) und die transversale Quarkspin Verteilungsfunktion {delta}{sub T}q(x). Diese letztgenannte Funktion, genannt ''Transversity'' Funktion, ist chiral ungerade und kann deshalb nur in Kombination mit einer anderen chiral ungeraden Funktion gemessen werden. Eine Zugangsmoeglichkeit zur ''Transversity'' Funktion {delta}{sub T}q(x) ist die semi-inklusive zwei Hadronenproduktion in tief inelastischer Streuung an einem transversal polarisierten Target. Dabei misst man die Faltung der chiral ungeraden zwei Hadronen Interferenz Fragmentationsfunktion (IFF) H{sub 1} {sup angle} (z,M{sub h}{sup 2}) und der chiral ungeraden ''Transversity'' Funktion. Die IFF H{sub 1} {sup angle} (z,M{sub h}{sup 2}) ist der spinabhaengige Teil einer Fragmentationsfunktion, die die Fragmentation eines transversal polarisierten Quarks in zwei unpolarisierte Hadronen beschreibt. Die Produktion der zwei Hadronen erfolgt in einer Interferenz zwischen verschiedenen Wellenzustaenden der Hadronenpaare. Man misst azimuthale Asymmetrien in den erzeugten Hadronenpaaren. Die Messungen, die in dieser Arbeit beschrieben werden, wurden am COMPASS Experiment am CERN in den Jahren 2002-2004 durchgefuehrt, welches ein Feststoff Target Experiment am SPS Beschleuniger ist. Nach einer Einfuehrung werden in Kapitel 2 die zugrundeliegenden theoretischen Konzepte zur Messung der ''Transversity'' Funktion vorgestellt. In Kapitel 3 wird das COMPASS Experiment beschrieben. Schliesslich werden in Kapitel 4 die Auswertemethoden besprochen, die Ergebnisse der azimuthalen Asymmetrien gezeigt und mit theoretischen Vorhersagen verglichen. (orig.)

  14. Identifizierung und Quantifizierung der PVC Weichmachermetabolite 2-Ethylhexansäure und 2-Ethyl-3-hydroxyhexansäure im Plasma mittels Gaschromatographie-Massenspektrometrie

    OpenAIRE

    Usta, Nirgül

    2006-01-01

    Phthalate werden als Weichmacher bei der Herstellung des Kunststoffes Polyvinylchlorid (PVC) eingesetzt. Sie besitzen die Eigenschaft, den Kunststoff flexibler und gleichzeitig strapazierfähiger zu machen. Aus diesem Grund begegnen uns Phthalate überall im Alltag, wie z.B. in der Kleidung, als Verpackungsmaterial, aber vor allem in der Medizin werden die Eigenschaften von Weichmachern genutzt. Die Belastung der gesamten Bevölkerung ist allgegenwärtig. Die größte Aufnahme von DEHP (Di(2-ethylh...

  15. Vermittlung von Naturheilverfahren in der Veterinärmedizin mittels E-Learning [Teaching methods of alternative therapy in veterinary medicine via e-learning

    Directory of Open Access Journals (Sweden)

    Fidelak, Christian

    2008-11-01

    Full Text Available [english] The Free University’s Veterinary Clinic of Reproduction in the Department of Veterinary Medicine, Berlin, has been offering courses on alternative and complementary veterinary medicine to its students for several years. Due to time constraints and shortages in teaching staff, it has not been possible to satisfy student demand for instruction in these areas. To provide more detailed information as well as more opportunities for discussion and practica, subject area courses were modified in two steps. Initially, blended learning was implemented to include e-learning and in-class formats of instruction. Subsequently, an entire block of courses offered were transferred to e-learning format. Students may now voluntarily register for the e-learning course entitled “Introduction of alternative and complementary veterinary medicine” via the Internet and learn the basic principles of homoeopathy, herbal medicine, acupuncture and other alternative methods in veterinary medicine. After passing this basic course, blended learning courses enable advanced students to learn more about fundamentals of methods in greater detail as well as to perform practica with animal subjects. The evaluation of these courses showed that students rated e-learning to be a reasonable addendum to in-class instruction. More than two thirds of the students recommended an increased integration of e-learning into veterinary education. [german] Die Tierklinik für Fortpflanzung in Berlin bietet den Studierenden der Veterinärmedizin seit einigen Semestern Wahlpflichtkurse zu den Naturheilverfahren an. Der enormen Nachfrage seitens der Studierenden standen personelle und zeitliche Begrenzungen des Lehrpersonals gegenüber. Um den Interessenten dennoch umfangreiche Informationen zu bieten sowie Freiräume für Diskussionen und praktische Übungen zu schaffen, wurde das Ausbildungsangebot in zwei Projektphasen ausgebaut. Zunächst wurde dabei die Methode des Blended-Learning genutzt. Anschließend wurde ein Teil des Kursangebotes komplett auf E-Learning umgestellt. Der Wahlpflichtkurs „Einführung in die Naturheilverfahren“ kann seither von den Studierenden vollständig über das Internet bearbeitet werden. Dieser Kurs behandelt die theoretischen Grundlagen von Homöopathie, Phytotherapie, Akupunktur und einigen weiteren Methoden. In Aufbaukursen werden neben einer Vertiefung der Grundlagen umfangreiche praktische Übungen durchgeführt. Die Evaluationsergebnisse belegen, dass die Studierenden E-Learning als sinnvolle Ergänzung der herkömmlichen Lehrmethoden betrachten. Zudem befürworten mehr als zwei Drittel der Studierenden eine vermehrte Einbindung von E-Learning in die Ausbildung.

  16. Das Ziel bestimmt die Mittel. Das Wirken Östen Undéns auf dem Weg zur schwedischen Neutralitätspolitik.

    Directory of Open Access Journals (Sweden)

    Peer Krumrey

    2009-12-01

    Full Text Available The Swedish policy of non-alliance aiming at neutrality in the event of war with all its contradictions and disputes continues to have an effect on societal debate in today’s Sweden. This article advocates a more accurate differentiation between historical processes and political assessments. It argues that this can be achieved by focussing on objectives set at that time as well as political outcomes resulting from the means chosen to achieve them rather than trying to compile moral benchmarks retrospectively. In order to exemplify this the article draws on the long-time Swedish foreign minister Östen Undén whose work is considered formative for Swedens foreign and security policy during the Cold War. It is stated that by using this approach it is possible to solve some of the prevailing contradictions and to demonstrate a higher degree of continuity.

  17. Regulation of acccess to natural gas on the basis of European competition law; Die Regulierung des Zugangs zu Erdgas mittels europaeischen Wettbewerbsrechts

    Energy Technology Data Exchange (ETDEWEB)

    Batzel, Reto H.

    2010-07-01

    It is a fact that competition in the natural gas sector has not been established so far. The author believes that this failure of the market structure in the European gas industries is a result of the world-wide increasing demand for natural gas, which is a finite commodity. The publication comprises four parts. The first part presents the legal fundamentals of the investigation. The second part explains how the fact that newcomers cannot compete for access to natural gas prevents competition in the European gas markets. The third part shows how equal access to natural gas of all market partners can be re-established on the basis of European cartel law, which is a precondition of competition in the European gas markets. The fourth part is an appendix with tables and graphs. The investigation was carried out on behalf of the German gas industry. (orig./RHM)

  18. Measurements of the hydroxyl radical concentration in the marine troposphere using laser-induced fluorescence; Messung der Hydroxylradikal-Konzentration in der marinen Troposphaere mittels laserinduzierter Fluoreszenz

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacek, M.

    2001-02-01

    The concentrations of OH and HO{sub 2} radicals were measured above the Atlantic ocean using LIF technique. The measurements were part of the field campaign ALBATROSS which took place abroad the German research vessel ''Polarstern'' in October 1996. Numerous diurnal cycles of OH and HO{sub 2} were recorded in the marine boundary layer between 24 N and 32 S latitude. In this background atmosphere the OH concentration proved to be proportional to the photolysis frequency J(O({sup 1}D)), whereas the HO{sub 2} concentration correlated with the square root of J(O({sup 1}D)). Furthermore, the calibration method for the LIF experiment was verified and improved. The method is based on the photolysis of water vapour at 185 nm for radical generation and the dissociation of oxygen for irradiation measurement in the flow reactor. (orig.)

  19. Untersuchungen zur oxidativen Entfärbung ausgewählter Reaktivfarbstoffe: Analyse der Abbauprodukte mittels hochauflösender LC-MS

    OpenAIRE

    Schellenträger, Marc

    2014-01-01

    The large amount of cotton that continues to be used for textiles means that reactive dyes are still quantitatively the most significant group of dyes. Dying cellulose textiles with reactive dyes is always accompanied by hydrolysis of the dye. The degree to which reactive dyes are fixed to the cellulose fibre is between 70 and 95 %. The dye hydrolysates negatively affect the wet fastness of the dyed textile. For this reason they have to be removed from the textile in an extensi...

  20. Diagnosis of SDAT by HMPAO SPECT and vitamin B{sub 12} serum concentration; Diagnostik der SDAT mittels HMPAO-SPECT und Serumvitamin-B{sub 12}-Spiegel

    Energy Technology Data Exchange (ETDEWEB)

    Mikosch, P. [Landeskrankenhaus Klagenfurt (Austria). Abt. fuer Nuklearmedizin; Gallowitsch, H.J. [Landeskrankenhaus Klagenfurt (Austria). Abt. fuer Nuklearmedizin; Gomez, I. [Landeskrankenhaus Klagenfurt (Austria). Abt. fuer Nuklearmedizin; Kresnik, E. [Landeskrankenhaus Klagenfurt (Austria). Abt. fuer Nuklearmedizin; Ploeb, H. [Landeskrankenhaus Klagenfurt (Austria). Abt. fuer Nuklearmedizin; Lind, P. [Landeskrankenhaus Klagenfurt (Austria). Abt. fuer Nuklearmedizin

    1995-06-01

    It is quite difficult to confirm the diagnosis of demential disorders, including senile dementia of the Alzheimer type (SDAT) by clinical means only. Through the combination of {sup 99m}Tc-HMPAO brain SPECT and serum vitamin B{sub 12} determination it was hoped to speed up and improve the diagnosis of SDAT. 116 patients who had been divided into four groups according to their defect pattern in the {sup 99m}Tc-HMPAO brain SPECT 17 very probably had SDAT; of these 15 showed a defect pattern with brain SPECT which could be associated to SDAT. The majority of SDAT patients had serum vitamin B{sub 12} levels in the lower normal range or pathologically below that range. Both investigations contributed to establishing the SDAT diagnosis without replacing other investigations. The determination of serum vitamin B{sub 12} does not require any major additional effort. (orig.) [Deutsch] Die alleinige klinische Abklaerung dementieller Zustandsbilder, so auch der senilen Demenz vom Alzheimertyp (SDAT), ist schwierig. Durch die Kombination von {sup 99m}Tc-HMPAO-Gehirn-SPECT und Serumvitamin-B{sub 12}-Bestimmung erwarteten wir eine Beschleunigung und Verbesserung der Diagnostik der SDAT. Von 116 Patienten, die in 4 Gruppen, entsprechend ihrem {sup 99m}Tc-HMPAO-Verteilungsmuster eingeteilt worden waren, konnten bei 17 klinisch sehr wahrscheinlichen SDAT-Patienten bei 15 Auffaelligkeiten mit Hinweis auf SDAT im Gehirn SPECT gefunden werden. Ein Teil der Patienten wies einen niedrig-normalen bzw. pathologisch niedrigen Vitamin-B{sub 12}-Spiegel auf. Andere Untersuchungen wuerden durch die Kombination von Gehirn-SPECT und Serumvitamin-B{sub 12}-Bestimmung nicht ueberfluessig werden, obwohl beide Untersuchungen Informationen lieferten, die die Zuordnung zur Diagnose SDAT erleichterten. Die zusaetzliche Serumvitamin-B{sub 12}-Bestimmung stellt keinen wesentlichen Mehraufwand dar. (orig.)