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Sample records for rankin utility authority

  1. Cascaded organic rankine cycles for waste heat utilization

    Science.gov (United States)

    Radcliff, Thomas D [Vernon, CT; Biederman, Bruce P [West Hartford, CT; Brasz, Joost J [Fayetteville, NY

    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.

  2. Performance Analysis of Organic Rankine-vapor Compression Ice Maker Utilizing Food Industry Waste Heat

    OpenAIRE

    Bing Hu; Yuanshu Cao; Weibin Ma

    2015-01-01

    To develop the organic Rankine-vapor compression ice maker driven by food industry exhaust gases and engine cooling water, an organic Rankine-vapor compression cycle system was employed for ice making and a thermodynamic model was developed and the effects of working fluid types, hot water temperature and condensation temperature on the system performance were analyzed and the ice making capacity from unit mass hot water and unit power waste heat were evaluated. The calculated results show th...

  3. 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.

  4. Exergy and economic analysis of organic rankine cycle hybrid system utilizing biogas and solar energy in rural area of China

    DEFF Research Database (Denmark)

    Zhao, Chunhua; Zheng, Siyu; Zhang, Ji

    2017-01-01

    Due to the existing huge biogas resource in the rural area of China, biogas is widely used for production and living. Cogeneration system provides an opportunity to realize the balanced utilization of the renewable energy such as biogas and solar energy. This paper presented a numerical...... investigation of a hybrid energy-driven organic Rankine cycle (ORC) cogeneration system, involving a solar organic Rankine cycle and a biogas boiler. The biogas boiler with a module of solar Parabolic-Trough Collectors (PTC) is employed to provide heat source to the ORC via two distinct intermediate pressurized...... circuits. The cogeneration supplied the power to the air-condition in summer condition and hot water, which is heated in the condenser, in winter condition. The system performance under the subcritical pressures has been assessed according to the energy-exergy and economic analysis with the organic working...

  5. Final Report. Conversion of Low Temperature Waste Heat Utilizing Hermetic Organic Rankine Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, Robert L.

    2005-04-20

    The design of waste heat recovery using the organic Rankine cycle (ORC) engine is updated. Advances in power electronics with lower cost enable the use of a single shaft, high-speed generator eliminating wear items and allowing hermetic sealing of the working fluid. This allows maintenance free operation and a compact configuration that lowers cost, enabling new market opportunities.

  6. Utilization of recently developed codes for high power Brayton and Rankine cycle power systems

    Science.gov (United States)

    Doherty, Michael P.

    1993-01-01

    Two recently developed FORTRAN computer codes for high power Brayton and Rankine thermodynamic cycle analysis for space power applications are presented. The codes were written in support of an effort to develop a series of subsystem models for multimegawatt Nuclear Electric Propulsion, but their use is not limited just to nuclear heat sources or to electric propulsion. Code development background, a description of the codes, some sample input/output from one of the codes, and state future plans/implications for the use of these codes by NASA's Lewis Research Center are provided.

  7. 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. P...

  8. Design and development of an automotive propulsion system utilizing a Rankine cycle engine (water based fluid). Final report

    Energy Technology Data Exchange (ETDEWEB)

    Demler, R.L.

    1977-09-01

    Under EPA and ERDA sponsorship, SES successfully designed, fabricated and tested the first federally sponsored steam powered automobile. The automobile - referred to as the simulator - is a 1975 Dodge Monaco standard size passenger car with the SES preprototype Rankine cycle automotive propulsion system mounted in the engine compartment. In the latter half of 1975, the simulator successfully underwent test operations at the facilities of SES in Watertown, Massachusetts and demonstrated emission levels below those of the stringent federally established automotive requirements originally set for implementation by 1976. The demonstration was accomplished during testing over the Federal Driving Cycle on a Clayton chassis dynamometer. The design and performance of the vehicle are described.

  9. Ideal Point Design and Operation of CO2-Based Transcritical Rankine Cycle (CTRC System Based on High Utilization of Engine’s Waste Heats

    Directory of Open Access Journals (Sweden)

    Lingfeng Shi

    2017-10-01

    Full Text Available This research conducted a study specially to systematically analyze combined recovery of exhaust gas and engine coolant and related influence mechanism, including a detailed theoretical study and an assistant experimental study. In this research, CO2-based transcritical Rankine cycle (CTRC was used for fully combining the wastes heats. The main objective of theoretical research was to search an ‘ideal point’ of the recovery system and related influence mechanism, which was defined as operating condition of complete recovery of two waste heats. The theoretical methodology of this study could also provide a design reference for effective combined recovery of two or multiple waste heats in other fields. Based on a kW-class preheated CTRC prototype that was designed by the ‘ideal point’ method, an experimental study was conducted to verify combined utilization degree of two engine waste heats by the CTRC system. The operating results showed that the prototype can gain 44.4–49.8 kW and 22.7–26.7 kW heat absorption from exhaust gas and engine coolant, respectively. To direct practical operation, an experimental optimization work on the operating process was conducted for complete recovery of engine coolant exactly, which avoided deficient or excessive recovery.

  10. Comparative Evaluation of Integrated Waste Heat Utilization Systems for Coal-Fired Power Plants Based on In-Depth Boiler-Turbine Integration and Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Shengwei Huang

    2018-01-01

    Full Text Available To maximize the system-level heat integration, three retrofit concepts of waste heat recovery via organic Rankine cycle (ORC, in-depth boiler-turbine integration, and coupling of both are proposed, analyzed and comprehensively compared in terms of thermodynamic and economic performances. For thermodynamic analysis, exergy analysis is employed with grand composite curves illustrated to identify how the systems are fundamentally and quantitatively improved, and to highlight key processes for system improvement. For economic analysis, annual revenue and investment payback period are calculated based on the estimation of capital investment of each component to identify the economic feasibility and competitiveness of each retrofit concept proposed. The results show that the in-depth boiler-turbine integration achieves a better temperature match of heat flows involved for different fluids and multi-stage air preheating, thus a significant improvement of power output (23.99 MW, which is much larger than that of the system with only ORC (6.49 MW. This is mainly due to the limitation of the ultra-low temperature (from 135 to 75 °C heat available from the flue gas for ORC. The thermodynamic improvement is mostly contributed by the reduction of exergy destruction within the boiler subsystem, which is eventually converted to mechanical power; while the exergy destruction within the turbine system is almost not changed for the three concepts. The selection of ORC working fluids is performed to maximize the power output. Due to the low-grade heat source, the cycle with R11 offers the largest additional net power generation but is not significantly better than the other preselected working fluids. Economically, the in-depth boiler-turbine integration is the most economic completive solution with a payback period of only 0.78 year. The ORC concept is less attractive for a sole application due to a long payback time (2.26 years. However, by coupling both

  11. Number theory and modular forms papers in memory of Robert A Rankin

    CERN Document Server

    Ono, Ken

    2003-01-01

    Robert A. Rankin, one of the world's foremost authorities on modular forms and a founding editor of The Ramanujan Journal, died on January 27, 2001, at the age of 85. Rankin had broad interests and contributed fundamental papers in a wide variety of areas within number theory, geometry, analysis, and algebra. To commemorate Rankin's life and work, the editors have collected together 25 papers by several eminent mathematicians reflecting Rankin's extensive range of interests within number theory. Many of these papers reflect Rankin's primary focus in modular forms. It is the editors' fervent hope that mathematicians will be stimulated by these papers and gain a greater appreciation for Rankin's contributions to mathematics. This volume would be an inspiration to students and researchers in the areas of number theory and modular forms.

  12. 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

    The organic Rankine cycle is a suitable technology for utilizing low grade heat for electricity production. Compared to the traditional steam Rankine cycle, the organic Rankine cycle is beneficial, since it enables the choice of a working fluid which performs better than steam at low heat input...... temperatures and at lowpower outputs. Selecting the process layout of the organic Rankine cycle and the working fluid are two key design decisions which are critical for the thermodynamic and economic performance of the cycle. The prevailing approach used in the design and optimization of organic Rankine...... product of the overall heat transfer coefficient and the heat transfer area) is assigned to the cycle, while the distribution of this total UA-value to each of the heat exchangers is optimized. Optimizations are carried out for three different marine engine waste heatsources at temperatures ranging from...

  13. 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.

  14. Development Credit Authority (DCA) Data Set: Guarantee Utilization and Claims

    Data.gov (United States)

    US Agency for International Development — USAID's Development Credit Authority (DCA) works with investors, local financial institutions, and development organizations to design and deliver investment...

  15. Rankine-cycle solar-cooling systems

    Science.gov (United States)

    Weathers, H. M.

    1979-01-01

    Report reviews progress made by three contractors to Marshall Space Flight Center and Department of Energy in developing Rankine-cycle machines for solar cooling and testing of commercially available equipment involved.

  16. Pueblo of Laguna Utility Authority Renewable Energy Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    Carolyn Stewart, Red Mountain Tribal Energy

    2008-03-31

    The project, “Renewable Energy Feasibility Study” was designed to expand upon previous work done by the Tribe in evaluating utility formation, generation development opportunities, examining options for creating self-sufficiency in energy matters, and integrating energy management with the Tribe’s economic development goals. The evaluation of project locations and economic analysis, led to a focus primarily on solar projects.

  17. Organic Rankine Cycles. Old wine in new bottles; Organic Rankine Cycles. Oude wijn in nieuwe zakken

    Energy Technology Data Exchange (ETDEWEB)

    Den Hartog, T.L.B. [Cumae, Arnhem (Netherlands)

    2007-05-15

    An overview is given of the renewed interest for the Organic Rankine Cycle technology and new developments with regard to this power generating technology. [Dutch] Een overzicht wordt gegeven van de hernieuwde belangstelling voor de Organic Rankine Cycle (ORC) technologie en nieuwe ontwikkeling m.b.t. deze vorm van elektriciteitopwekking.

  18. 76 FR 44763 - Authority To Designate Financial Market Utilities as Systemically Important

    Science.gov (United States)

    2011-07-27

    ... 1320 RIN 4030-AA01 Authority To Designate Financial Market Utilities as Systemically Important AGENCY... Council (the ``Council'') the authority to designate a financial market utility (``FMU'') that the Council... spreading among financial institutions or markets and thereby threaten the stability of the United States...

  19. 75 FR 79982 - Authority To Designate Financial Market Utilities as Systemically Important

    Science.gov (United States)

    2010-12-21

    ...; ] FINANCIAL STABILITY OVERSIGHT COUNCIL 12 CFR Chapter XIII Authority To Designate Financial Market Utilities... designate as systemically important a financial market utility if the Council determines that the failure, or a disruption to the functioning, of a financial market utility could create or increase the risk...

  20. Navajo Tribal Utility Authority Shiprock Wastewater Treatment Facility; Draft NPDES Permit

    Science.gov (United States)

    EPA is proposing to issue a NPDES permit (No. NN0020621) to Navajo Tribal Utility Authority (NTUA) for the Shiprock wastewater treatment facility in San Juan County, New Mexico, within the northeastern portion of the Navajo Nation.

  1. Method of optimizing performance of Rankine cycle power plants. [US DOE Patent

    Science.gov (United States)

    Pope, W.L.; Pines, H.S.; Doyle, P.A.; Silvester, L.F.

    1980-06-23

    A method is described for efficiently operating a Rankine cycle power plant to maximize fuel utilization efficiency or energy conversion efficiency or minimize costs by selecting a turbine fluid inlet state which is substantially on the area adjacent and including the transposed critical temperature line.

  2. Investigations on the application of zeotropic fluid mixtures in the organic rankine cycle for the geothermal power generation; Untersuchung zum Einsatz von zeotropen Fluidgemischen im Organic Rankine Cycle fuer die geothermische Stromerzeugung

    Energy Technology Data Exchange (ETDEWEB)

    Heberle, Florian

    2013-04-01

    The organic rankine cycle is a thermodynamic cycle process which uses an organic fluid working fluid instead of water in comparison to the commercial rankine process. The organic rankine cycle facilitates sufficiently high pressures at moderate temperatures. The organic rankine cycle significantly expands the technically possible and economically feasible ranges of application of such heat and power processes. The geothermal power is a very attractive field of application. Thermal water with a temperature of nearly 100 Celsius can be used for the power generation by means of the organic rankine cycle. Especially zeotropic mixtures are interesting as a working fluid. This is due to a non-isothermal phase change to a temperature glide which adapts very well to the temperature progress of the heat source. The author of the book under consideration reports on the application of different mixtures in the organic rankine cycle. The evaluation is based on a thermodynamic analysis and considers also toxicological, ecologic, technical as well as economic aspects.

  3. Affordable Rankine Cycle Waste Heat Recovery for Heavy Duty Trucks

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, Swami Nathan [Eaton Corporation

    2017-06-30

    Nearly 30% of fuel energy is not utilized and wasted in the engine exhaust. Organic Rankine Cycle (ORC) based waste heat recovery (WHR) systems offer a promising approach on waste energy recovery and improving the efficiency of Heavy-Duty diesel engines. Major barriers in the ORC WHR system are the system cost and controversial waste heat recovery working fluids. More than 40% of the system cost is from the additional heat exchangers (recuperator, condenser and tail pipe boiler). The secondary working fluid loop designed in ORC system is either flammable or environmentally sensitive. The Eaton team investigated a novel approach to reduce the cost of implementing ORC based WHR systems to Heavy-Duty (HD) Diesel engines while utilizing safest working fluids. Affordable Rankine Cycle (ARC) concept aimed to define the next generation of waste energy recuperation with a cost optimized WHR system. ARC project used engine coolant as the working fluid. This approach reduced the need for a secondary working fluid circuit and subsequent complexity. A portion of the liquid phase engine coolant has been pressurized through a set of working fluid pumps and used to recover waste heat from the exhaust gas recirculation (EGR) and exhaust tail pipe exhaust energy. While absorbing heat, the mixture is partially vaporized but remains a wet binary mixture. The pressurized mixed-phase engine coolant mixture is then expanded through a fixed-volume ratio expander that is compatible with two-phase conditions. Heat rejection is accomplished through the engine radiator, avoiding the need for a separate condenser. The ARC system has been investigated for PACCAR’s MX-13 HD diesel engine.

  4. 76 FR 17047 - Authority To Designate Financial Market Utilities as Systemically Important

    Science.gov (United States)

    2011-03-28

    ... OVERSIGHT COUNCIL 12 CFR Part 1320 RIN 4030-AA01 Authority To Designate Financial Market Utilities as... significant liquidity or credit problems spreading among financial institutions or markets and thereby... financial markets to support and facilitate the transferring, clearing or settlement of financial...

  5. 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.

  6. Organic rankine cycle waste heat applications

    Science.gov (United States)

    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. Working fluids selection for fishing boats waste heat powered organic Rankine-vapor compression ice maker

    Science.gov (United States)

    Bu, Xianbiao; Wang, Lingbao; Li, Huashan

    2014-10-01

    To utilize waste heat from fishing boats, an organic Rankine cycle/vapor compression cycle system was employed for ice making and a thermodynamic model was developed. Six working fluids were selected and compared in order to identify suitable working fluids which may yield high system efficiencies. The calculated results show that R600a is most suitable working fluid through comprehensive comparison of efficiency, size parameter, pressure ratio, coefficient of performance, system pressure and safety.

  8. 77 FR 26537 - City of Alexandria, LA, Louisiana Energy and Power Authority, Lafayette Utilities System v. Cleco...

    Science.gov (United States)

    2012-05-04

    ... Energy Regulatory Commission City of Alexandria, LA, Louisiana Energy and Power Authority, Lafayette Utilities System v. Cleco Power, LLC; Notice of Complaint Take notice that on April 25, 2012, pursuant to..., City of Alexandria, Louisiana, Louisiana Energy and Power Authority, and Lafayette Utilities System...

  9. Advanced Rankine and Brayton cycle power systems: Materials needs and opportunities

    Science.gov (United States)

    Grisaffe, S. J.; Guentert, D. C.

    1974-01-01

    Conceptual advanced potassium Rankine and closed Brayton power conversion cycles offer the potential for improved efficiency over steam systems through higher operating temperatures. However, for utility service of at least 100,000 hours, materials technology advances will be needed for such high temperature systems. Improved alloys and surface protection must be developed and demonstrated to resist coal combustion gases as well as potassium corrosion or helium surface degradation at high temperatures. Extensions in fabrication technology are necessary to produce large components of high temperature alloys. Long time property data must be obtained under environments of interest to assure high component reliability.

  10. Advanced Rankine and Brayton cycle power systems - Materials needs and opportunities

    Science.gov (United States)

    Grisaffe, S. J.; Guentert, D. C.

    1974-01-01

    Conceptual advanced potassium Rankine and closed Brayton power conversion cycles offer the potential for improved efficiency over steam systems through higher operating temperatures. However, for utility service of at least 100,000 hours, materials technology advances will be needed for such high temperature systems. Improved alloys and surface protection must be developed and demonstrated to resist coal combustion gases as well as potassium corrosion or helium surface degradation at high temperatures. Extensions in fabrication technology are necessary to produce large components of high temperature alloys. Long-time property data must be obtained under environments of interest to assure high component reliability.

  11. 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

    natural gas (LNG). The study compares the performance of six different ORC configurations both in design and off-design operation, and provides guidelines with respect to the most promising heat sources and sinks to be utilized by an ORC unit in order to maximize the annual fuel savings. In addition......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...

  12. The dish-Rankine SCSTPE program (Engineering Experiment no. 1)

    Science.gov (United States)

    Pons, R. L.; Grigsby, C. E.

    1980-05-01

    Activities planned for phase 2 Of the Small Community Solar Thermal Power Experiment (PFDR) program are summarized with emphasis on a dish-Rankine point focusing distributed receiver solar thermal electric system. Major design efforts include: (1) development of an advanced concept indirect-heated receiver;(2) development of hardware and software for a totally unmanned power plant control system; (3) implementation of a hybrid digital simulator which will validate plant operation prior to field testing; and (4) the acquisition of an efficient organic Rankine cycle power conversion unit. Preliminary performance analyses indicate that a mass-produced dish-Rankine PFDR system is potentially capable of producing electricity at a levelized busbar energy cost of 60 to 70 mills per KWh and with a capital cost of about $1300 per KW.

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

    Science.gov (United States)

    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.

  14. 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.

  15. Exergy analysis of micro-organic Rankine power cycles for a small scale solar driven reverse osmosis desalination system

    Energy Technology Data Exchange (ETDEWEB)

    Tchanche, B.F.; Lambrinos, Gr.; Frangoudakis, A.; Papadakis, G. [Department of Natural Resources and Agricultural Engineering, Agricultural University of Athens, 75 Iera Odos Street, 11855 Athens (Greece)

    2010-04-15

    Exergy analysis of micro-organic Rankine heat engines is performed to identify the most suitable engine for driving a small scale reverse osmosis desalination system. Three modified engines derived from simple Rankine engine using regeneration (incorporation of regenerator or feedliquid heaters) are analyzed through a novel approach, called exergy-topological method based on the combination of exergy flow graphs, exergy loss graphs, and thermoeconomic graphs. For the investigations, three working fluids are considered: R134a, R245fa and R600. The incorporated devices produce different results with different fluids. Exergy destruction throughout the systems operating with R134a was quantified and illustrated using exergy diagrams. The sites with greater exergy destruction include turbine, evaporator and feedliquid heaters. The most critical components include evaporator, turbine and mixing units. A regenerative heat exchanger has positive effects only when the engine operates with dry fluids; feedliquid heaters improve the degree of thermodynamic perfection of the system but lead to loss in exergetic efficiency. Although, different modifications produce better energy conversion and less exergy destroyed, the improvements are not significant enough and subsequent modifications of the simple Rankine engine cannot be considered as economically profitable for heat source temperature below 100 C. As illustration, a regenerator increases the system's energy efficiency by 7%, the degree of thermodynamic perfection by 3.5% while the exergetic efficiency is unchanged in comparison with the simple Rankine cycle, with R600 as working fluid. The impacts of heat source temperature and pinch point temperature difference on engine's performance are also examined. Finally, results demonstrate that energy analysis combined with the mathematical graph theory is a powerful tool in performance assessments of Rankine based power systems and permits meaningful comparison of

  16. 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.

  17. 78 FR 48668 - PSEG Long Island LLC, Long Island Electric Utility Servco LLC, Long Island Power Authority, Long...

    Science.gov (United States)

    2013-08-09

    ... Energy Regulatory Commission PSEG Long Island LLC, Long Island Electric Utility Servco LLC, Long Island Power Authority, Long Island Lighting Company; Notice of Petition for Declaratory Order Take notice that...) Rules of Practice and Procedure, 18 CFR 385.207, PSEG Long Island LLC (PSEG LI), Long Island Electric...

  18. Letter to the Editor, The Authors Reply: "Cost and Utility of Thrombophilia Testing".

    Science.gov (United States)

    Petrilli, Christopher M; Heidemann, Lauren; Mack, Megan; Durance, Paul; Chopra, Vineet

    2017-09-01

    We thank Dr. Berse and colleagues for their correspondence about our paper. We are pleased they agreed with our conclusion: Thrombophilia testing has limited clinical utility in most inpatient settings. © 2017 Society of Hospital Medicine.

  19. Rankine-Brayton engine powered solar thermal aircraft

    Science.gov (United States)

    Bennett, Charles L [Livermore, CA

    2009-12-29

    A solar thermal powered aircraft powered by heat energy from the sun. A Rankine-Brayton hybrid cycle heat engine is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller or other mechanism for enabling sustained free flight. The Rankine-Brayton engine has a thermal battery, preferably containing a lithium-hydride and lithium mixture, operably connected to it so that heat is supplied from the thermal battery to a working fluid. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

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

    DEFF Research Database (Denmark)

    Imran, Muhammad; Haglind, Fredrik; Asim, Muhammad

    2018-01-01

    Expanded. Different aspects of the publications were analyzed, such as publication type, major research areas, journals, citations, authorship pattern, affiliations as well as the keyword occurrence frequency. The impact factor, h-index and number of citations were used to investigate the strength...... 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......, respectively, corresponding to 17 citations per paper and an impact factor of 2.168 per publication. The research articles originate primarily from China, the USA, and European countries. Results indicate that China, the United States, Italy, Greece, Belgium, Spain, Germany and the United Kingdom...

  1. 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.

  2. Descriptive review and analysis of immunoglobulin utilization management from 2,548 prior authorization requests.

    Science.gov (United States)

    Tonkovic, Brian; Rutishauser, Linda K

    2014-04-01

    Immunoglobulin (Ig) is a costly blood product prescribed as immune replacement or modulation therapy to treat a wide spectrum of medical conditions. While the FDA has approved Ig for a limited number of indications, there are multiple off-label uses that have demonstrated proven clinical benefit or are currently in various phases of clinical study. There are also diagnoses for which Ig is prescribed, but for which no evidence-based efficacy data are available. Many conditions for which Ig has been prescribed are extremely rare, and a controlled clinical trial is not logistically possible. These conditions may be denied insurance authorization because of limited medical evidence that supports the use of Ig in their treatment. This limited evidence consists of uncontrolled studies, case series and reports, and expert opinion. Limiting the use of Ig therapy to cases with the best supporting evidence may control health care expenditure, but it may also limit the potential body of knowledge from publications by physicians with experience in treating these conditions. Specialty pharmacy providers can collect longitudinal outcomes, and data from their publications could provide support for improved managed care criteria or areas of future medical research. To (a) assess levels of supporting evidence by diagnosis for a sample of Ig requests submitted through the managed care prior authorization (PA) process and (b) provide a descriptive review of such requests and resultant benefit coverage determinations by individual diagnosis, overarching diagnostic category, patient age group, and assessed levels of evidence. Through collaboration with 6 health plans, we obtained and analyzed 2,548 managed care PA requests for Ig therapy received between February 2008 and August 2012, as well as resulting benefit coverage determinations. A literature review of 7 established treatment guidelines and expert consensus statements was conducted and used to evaluate all indications for Ig

  3. 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...... included numerical simulations and experimental tests on a 125 kW demonstration ORC unit that utilizes the waste heat of the main engine cooling system on board one of Mærsk's container vessels. During the design of the demonstration ORC unit, different alternatives for the condenser were analyzed in order...... to minimize the size of the heat exchanger area. Later on the ORC unit was successfully installed on board, and it has been working uninterruptedly since, demonstrating the matureness of the ORC technology for maritime applications. During the onboard testing, additional measuring devices were installed...

  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. Rethinking Racism in Claudia Rankine's Citizen: An American Lyric

    OpenAIRE

    Hersi, Asli

    2016-01-01

    The issue of race in America in the twenty-first century is still a turbulent matter. The end of segregation in schools, politics, marriages and workplaces created a mask that hid racial inequalities and injustices (Whitmarsh 1). In a time where police brutalities have frequently surfaced in the media in a supposed “post-racial America”, Claudia Rankine writes a thought-provoking 160 page long “book-length poem” about everyday racism arguing that the overlooking of microaggressions (brief dai...

  6. Rethinking Racism in Claudia Rankine's Citizen: An American Lyric

    OpenAIRE

    Hersi, Asli

    2016-01-01

    Master's thesis in Literacy studies The issue of race in America in the twenty-first century is still a turbulent matter. The end of segregation in schools, politics, marriages and workplaces created a mask that hid racial inequalities and injustices (Whitmarsh 1). In a time where police brutalities have frequently surfaced in the media in a supposed “post-racial America”, Claudia Rankine writes a thought-provoking 160 page long “book-length poem” about everyday racism arguing that the ove...

  7. Organic Rankine Cycle System Analysis for Low GWP Working Fluids

    OpenAIRE

    Datla, Bala Varma; Brasz, Joost

    2012-01-01

    The last decade has seen a substantial increase in Organic Rankine Cycle system installations for low temperature waste heat power recovery. The availability of HFC245fa has played a major role in this recent surge in ORC systems since it allows the use of existing HVAC hardware (heat exchangers and compressors) to be used as ORC components (turbines, boilers and condensers) with minimal redesign. The environmental drawback of HFC245fa is its relatively high GWP value of 950. The advent of a ...

  8. 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)

  9. Time domain Rankine-Green panel method for offshore structures

    Science.gov (United States)

    Li, Zhifu; Ren, Huilong; Liu, Riming; Li, Hui

    2017-02-01

    To solve the numerical divergence problem of the direct time domain Green function method for the motion simulation of floating bodies with large flare, a time domain hybrid Rankine-Green boundary element method is proposed. In this numerical method, the fluid domain is decomposed by an imaginary control surface, at which the continuous condition should be satisfied. Then the Rankine Green function is adopted in the inner domain. The transient free surface Green function is applied in the outer domain, which is used to find the relationship between the velocity potential and its normal derivative for the inner domain. Besides, the velocity potential at the mean free surface between body surface and control surface is directly solved by the integration scheme. The wave exciting force is computed through the convolution integration with wave elevation, by introducing the impulse response function. Additionally, the nonlinear Froude-Krylov force and hydrostatic force, which is computed under the instantaneous incident wave free surface, are taken into account by the direct pressure integration scheme. The corresponding numerical computer code is developed and first used to compute the hydrodynamic coefficients of the hemisphere, as well as the time history of a ship with large flare; good agreement is obtained with the analytical solutions as well as the available numerical results. Then the hydrodynamic properties of a FPSO are studied. The hydrodynamic coefficients agree well with the results computed by the frequency method; the influence of the time interval and the truncated time is investigated in detail.

  10. 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 cycl...

  11. 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.

  12. Organic Rankine Kilowatt Isotope Power System. Final phase I report

    Energy Technology Data Exchange (ETDEWEB)

    1978-07-15

    On 1 August 1975 under Department of Energy Contract EN-77-C-02-4299, Sundstrand Energy Systems commenced development of a Kilowatt Isotope Power System (KIPS) directed toward satisfying the higher power requirements of satellites of the 1980s and beyond. The KIPS is a /sup 238/PuO/sub 2/ fueled organic Rankine cycle turbine power system which will provide design output power in the range of 500 to 2000 W/sub (e)/ with a minimum of system changes. The principal objectives of the Phase 1 development effort were to: conceptually design a flight system; design a Ground Demonstration System (GDS) that is prototypic of the flight system in order to prove the feasibility of the flight system design; fabricate and assemble the GDS; and performance and endurance test the GDS using electric heaters in lieu of the isotope heat source. Results of the work performed under the Phase 1 contract to 1 July 1978 are presented.

  13. Solar-powered Rankine heat pump for heating and cooling

    Science.gov (United States)

    Rousseau, J.

    1978-01-01

    The design, operation and performance of a familyy of solar heating and cooling systems are discussed. The systems feature a reversible heat pump operating with R-11 as the working fluid and using a motor-driven centrifugal compressor. In the cooling mode, solar energy provides the heat source for a Rankine power loop. The system is operational with heat source temperatures ranging from 155 to 220 F; the estimated coefficient of performance is 0.7. In the heating mode, the vapor-cycle heat pump processes solar energy collected at low temperatures (40 to 80 F). The speed of the compressor can be adjusted so that the heat pump capacity matches the load, allowing a seasonal coefficient of performance of about 8 to be attained.

  14. 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

    Small-Scale W912H0-12-C-0059 Organic Rankine Cycle (ORC) Engine /Generator Technology 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( SI 5d...same fuel input. This value is used for calculation of Greenhouse Gas (GHG) reductions and economic results. Life cycle economics of the system are...associated with engine and other electric generator systems , waste heat from steam or heat distribution, waste heat from boiler exhausts, and heat

  15. Analysis of a rotating spool expander for Organic Rankine Cycle applications

    Science.gov (United States)

    Krishna, Abhinav

    Increasing interest in recovering or utilizing low-grade heat for power generation has prompted a search for ways in which the power conversion process may be enhanced. Amongst the conversion systems, the Organic Rankine Cycle (ORC) has generated an enormous amount of interest amongst researchers and system designers. Nevertheless, component level technologies need to be developed and match the range of potential applications. In particular, technical challenges associated with scaling expansion machines (turbines) from utility scale to commercial scale have prevented widespread adoption of the technology. In this regard, this work focuses on a novel rotating spool expansion machine at the heart of an Organic Rankine Cycle. A comprehensive, deterministic simulation model of the rotating spool expander is developed. The comprehensive model includes a detailed geometry model of the spool expander and the suction valve mechanism. Sub-models for mass flow, leakage, heat transfer and friction within the expander are also developed. Apart from providing the ability to characterize the expander in a particular system, the model provides a valuable tool to study the impact of various design variables on the performance of the machine. The investigative approach also involved an experimental program to assess the performance of a working prototype. In general, the experimental data showed that the expander performance was sub-par, largely due to the mismatch of prevailing operating conditions and the expander design criteria. Operating challenges during the shakedown tests and subsequent sub-optimal design changes also detracted from performance. Nevertheless, the results of the experimental program were sufficient for a proof-of-concept assessment of the expander and for model validation over a wide range of operating conditions. The results of the validated model reveal several interesting details concerning the expander design and performance. For example, the match

  16. Performance Evaluation of a Helical Coil Heat Exchanger Working under Supercritical Conditions in a Solar Organic Rankine Cycle Installation

    Directory of Open Access Journals (Sweden)

    Marija Lazova

    2016-06-01

    Full Text Available Worldwide interest in low grade heat valorization using organic Rankine cycle (ORC technologies has increased significantly. A new small-scale ORC with a net capacity of 3 kW was efficiently integrated with a concentrated solar power technology for electricity generation. The excess heat source from Photovoltaic (PV collectors with a maximum temperature of 100 °C was utilized through a supercritical heat exchanger that uses R-404A as working medium. By ensuring supercritical heat transfer leads to a better thermal match in the heat exchanger and improved overall cycle efficiency. A helical coil heat exchanger was designed by using heat transfer correlations from the literature. These heat transfer correlations were derived for different conditions than ORCs and their estimated uncertainty is ~20%. In order to account for the heat transfer correlation uncertainties this component was oversized by 20%. Next, a prototype was built and installed in an integrated concentrated photovoltaic/thermal (CPV/T/Rankine system. The results from the measurements show that for better estimation of the sizing of the heat exchanger a more accurate correlation is required in order to design an optimal configuration and thus employ cheaper components.

  17. 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...... 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...... field made of parabolic trough collectors and a recuperative organic Rankine cycle. Pressurized water is selected as heat transfer fluid and its maximum temperature is fixed to 150°C. The target power output for the plant is 100 kWel. A part load analysis is carried out in order to define the most...

  18. Thermodynamic Analysis of a Rankine Cycle Powered Vapor Compression Ice Maker Using Solar Energy

    National Research Council Canada - National Science Library

    Hu, Bing; Bu, Xianbiao; Ma, Weibin

    2014-01-01

      To develop the organic Rankine-vapor compression ice maker driven by solar energy, a thermodynamic model was developed and the effects of generation temperature, condensation temperature, and working...

  19. Thermodynamic analysis of a Rankine cycle powered vapor compression ice maker using solar energy

    National Research Council Canada - National Science Library

    Hu, Bing; Bu, Xianbiao; Ma, Weibin

    2014-01-01

    To develop the organic Rankine-vapor compression ice maker driven by solar energy, a thermodynamic model was developed and the effects of generation temperature, condensation temperature, and working...

  20. Potential Chemical Effects of Changes in the Source of Water Supply for the Albuquerque Bernalillo County Water Utility Authority

    Science.gov (United States)

    Bexfield, Laura M.; Anderholm, Scott K.

    2008-01-01

    Chemical modeling was used by the U.S. Geological Survey, in cooperation with the Albuquerque Bernalillo County Water Utility Authority (henceforth, Authority), to gain insight into the potential chemical effects that could occur in the Authority's water distribution system as a result of changing the source of water used for municipal and industrial supply from ground water to surface water, or to some mixture of the two sources. From historical data, representative samples of ground-water and surface-water chemistry were selected for modeling under a range of environmental conditions anticipated to be present in the distribution system. Mineral phases calculated to have the potential to precipitate from ground water were compared with the compositions of precipitate samples collected from the current water distribution system and with mineral phases calculated to have the potential to precipitate from surface water and ground-water/surface-water mixtures. Several minerals that were calculated to have the potential to precipitate from ground water in the current distribution system were identified in precipitate samples from pipes, reservoirs, and water heaters. These minerals were the calcium carbonates aragonite and calcite, and the iron oxides/hydroxides goethite, hematite, and lepidocrocite. Several other minerals that were indicated by modeling to have the potential to precipitate were not found in precipitate samples. For most of these minerals, either the kinetics of formation were known to be unfavorable under conditions present in the distribution system or the minerals typically are not formed through direct precipitation from aqueous solutions. The minerals with potential to precipitate as simulated for surface-water samples and ground-water/surface-water mixtures were quite similar to the minerals with potential to precipitate from ground-water samples. Based on the modeling results along with kinetic considerations, minerals that appear most likely to

  1. Rankin-Selberg methods for closed string amplitudes

    CERN Document Server

    Pioline, Boris

    2014-01-01

    After integrating over supermoduli and vertex operator positions, scattering amplitudes in superstring theory at genus $h\\leq 3$ are reduced to an integral of a Siegel modular function of degree $h$ on a fundamental domain of the Siegel upper half plane. A direct computation is in general unwieldy, but becomes feasible if the integrand can be expressed as a sum over images under a suitable subgroup of the Siegel modular group: if so, the integration domain can be extended to a simpler domain at the expense of keeping a single term in each orbit -- a technique known as the Rankin-Selberg method. Motivated by applications to BPS-saturated amplitudes, Angelantonj, Florakis and I have applied this technique to one-loop modular integrals where the integrand is the product of a Siegel-Narain theta function times a weakly, almost holomorphic modular form. I survey our main results, and take some steps in extending this method to genus greater than one.

  2. 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.

  3. Deriving modified Rankin scores from medical case-records.

    Science.gov (United States)

    Quinn, Terence J; Ray, Gautamananda; Atula, Sari; Walters, Matthew R; Dawson, Jesse; Lees, Kennedy R

    2008-12-01

    Modified Rankin score (mRS) is traditionally graded using a face-to-face or telephone interview. Certain stroke assessment scales can be derived from a review of a patient's case-record alone. We hypothesized that mRS could be successfully derived from the narrative within patient case-records. Sequential patients attending our cerebrovascular outpatient clinic were included. Two independent, blinded clinicians, trained in mRS, assessed case-records to derive mRS. They scored "certainty" of their grading on a 5-point Likert scale. Agreement between derived and traditional face-to-face mRS was calculated using attribute agreement analysis. Fifty patients with a range of disabilities were included. Case-record appraisers were poor at deriving mRS (k=0.34 against standard). Derived mRS grades showed poor agreement between observers (k=0.33). There was no relationship between certainty of derived mRS and proportion of correct grades (P=0.727). Accurate mRS cannot be derived from standard hospital records. Direct mRS interview is still required for clinical trials.

  4. Organic Rankine cycle - review and research directions in engine applications

    Science.gov (United States)

    Panesar, Angad

    2017-11-01

    Waste heat to power conversion using Organic Rankine Cycles (ORC) is expected to play an important role in CO2 reductions from diesel engines. Firstly, a review of automotive ORCs is presented focusing on the pure working fluids, thermal architectures and expanders. The discussion includes, but is not limited to: R245fa, ethanol and water as fluids; series, parallel and cascade as architectures; dry saturated, superheated and supercritical as expansion conditions; and scroll, radial turbine and piston as expansion machines. Secondly, research direction in versatile expander and holistic architecture (NOx + CO2) are proposed. Benefits of using the proposed unconventional approaches are quantified using Ricardo Wave and Aspen HYSYS for diesel engine and ORC modelling. Results indicate that, the implementation of versatile piston expander tolerant to two-phase and using cyclopentane can potentially increase the highway drive cycle power by 8%. Furthermore, holistic architecture offering complete utilisation of charge air and exhaust recirculation heat increased the performance noticeably to 5% of engine power at the design point condition.

  5. Biogas Engine Waste Heat Recovery Using Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Alberto Benato

    2017-03-01

    Full Text Available Italy is a leading country in the biogas sector. Energy crops and manure are converted into biogas using anaerobic digestion and, then, into electricity using internal combustion engines (ICEs. Therefore, there is an urgent need for improving the efficiency of these engines taking the real operation into account. To this purpose, in the present work, the organic Rankine cycle (ORC technology is used to recover the waste heat contained in the exhaust gases of a 1 MWel biogas engine. The ICE behavior being affected by the biogas characteristics, the ORC unit is designed, firstly, using the ICE nameplate data and, then, with data measured during a one-year monitoring activity. The optimum fluid and the plant configuration are selected in both cases using an “in-house” optimization tool. The optimization goal is the maximization of the net electric power while the working fluid is selected among 115 pure fluids and their mixtures. Results show that a recuperative ORC designed using real data guarantees a 30% higher net electric power than the one designed with ICE nameplate conditions.

  6. 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

  7. 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.

  8. Thermal analysis of a Phase Change Material for a Solar Organic Rankine Cycle

    Science.gov (United States)

    Iasiello, M.; Braimakis, K.; Andreozzi, A.; Karellas, S.

    2017-11-01

    Organic Rankine Cycle (ORC) is a promising technology for low temperature power generation, for example for the utilization of medium temperature solar energy. Since heat generated from solar source is variable throughout the day, the implementation of Thermal Energy Storage (TES) systems to guarantee the continuous operation of solar ORCs is a critical task, and Phase Change Materials (PCM) rely on latent heat to store large amounts of energy. In the present study, a thermal analysis of a PCM for a solar ORC is carried out. Three different types of PCMs are analyzed. The energy equation for the PCM is modeled by using the heat capacity method, and it is solved by employing a 1Dexplicit finite difference scheme. The solar source is modeled with a time-variable temperature boundary condition, with experimental data taken from the literature for two different solar collectors. Results are presented in terms of temperature profiles and stored energy. It has been shown that the stored energy depends on the heat source temperature, on the employed PCM and on the boundary conditions. It has been demonstrated that the use of a metal foam can drastically enhance the stored energy due to the higher overall thermal conductivity.

  9. Energy analysis of a trigeneration plant based on solid oxide fuel cell and organic Rankine cycle

    Energy Technology Data Exchange (ETDEWEB)

    Al-Sulaiman, Fahad A. [Mechanical and Aerospace Engineering Department, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario (Canada); Dincer, Ibrahim [Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, Ontario (Canada); Hamdullahpur, Feridun [Mechanical and Mechatronics Engineering Department, University of Waterloo, 200 University Avenue West, Waterloo, Ontario (Canada)

    2010-05-15

    In this study, energy analysis of a trigeneration plant based on solid oxide fuel cell (SOFC) and organic Rankine cycle (ORC) is conducted. The physical and thermodynamic elements of the plant include an SOFC, an ORC, a heat exchanger for the heating process and a single-effect absorption chiller for cooling. The results obtained from this study show that there is at least a 22% gain in efficiency using the trigeneration plant compared with the power cycle (SOFC and ORC). The study also shows that the maximum efficiency of the trigeneration plant is 74%, heating cogeneration is 71%, cooling cogeneration is 57% and net electricity is 46%. Furthermore, it is found that the highest net power output that can be provided by the trigeneration plant considered in this study is 540 kW and, the highest SOFC-AC power is 520 kW. The study reveals that the inlet pressure of the turbine has an insignificant effect on the efficiency. The study also examines the effect of both the SOFC current density and the SOFC inlet flow temperature on the cell voltage and voltage loss. (author)

  10. Corrections to the Rankine-Hugoniot conditions for curved shock waves

    Science.gov (United States)

    Lancellotti, Carlo; Yue, Yubei

    2014-12-01

    Several years ago, Carlo Cercignani and one of the authors in a paper (C. Cercignani, 2991) performed a mathe-matical analysis of the corrections to the Rankine-Hugoniot conditions due to the curvature of a shock front, using singular perturbation methods in order to "connect" the solutions to the the Boltzmann equation inside and outside the shock layer. It turned out that these corrections can be obtained at leading order by integrating appropriately the Boltzmann shock profile for a planar (one-dimensional in space) shock wave. However, they are entirely due to the spatially asymmetry of the shock, and they vanish if the shock is described using a simple bi-modal ansatz like the well-know Mott-Smith model. In the present work we extend and simplify the previous results, and then use a recently-developed deterministic (spectral) Boltzmann solver for a gas of hard-spheres in order to obtain accurate numerical values for the curvature corrections.

  11. 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.

  12. 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.

  13. 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)

  14. 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

    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...... 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...

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

    DEFF Research Database (Denmark)

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

    2018-01-01

    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......-butane yields the best compromise in terms of cycle net power output, turbine cost and efficiency for the considered case study. When a conservative design approach is adopted, the turbine features a two-stage configuration with supersonic converging nozzles and post-expansion. Conversely, a single...... 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...

  16. 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......-butane yields the best compromise in terms of cycle net power output, turbine cost and efficiency for the considered case study. When a conservative design approach is adopted, the turbine features a two-stage configuration with supersonic converging nozzles and post-expansion. Conversely, a single...... 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...

  17. Thermodynamic analysis of a Rankine cycle powered vapor compression ice maker using solar energy.

    Science.gov (United States)

    Hu, Bing; Bu, Xianbiao; Ma, Weibin

    2014-01-01

    To develop the organic Rankine-vapor compression ice maker driven by solar energy, a thermodynamic model was developed and the effects of generation temperature, condensation temperature, and working fluid types on the system performance were analyzed. The results show that the cooling power per square meter collector and ice production per square meter collector per day depend largely on generation temperature and condensation temperature and they increase firstly and then decrease with increasing generation temperature. For every working fluid there is an optimal generation temperature at which organic Rankine efficiency achieves the maximum value. The cooling power per square meter collector and ice production per square meter collector per day are, respectively, 126.44 W m(-2) and 7.61 kg m(-2) day(-1) at the generation temperature of 140 °C for working fluid of R245fa, which demonstrates the feasibility of organic Rankine cycle powered vapor compression ice maker.

  18. 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...... solar collectors (hot water temperature equal to 75 degrees C), R1234yf is the optimal solution. The heat exchanger volume ranges between 6.0 and 23.0 dm(3), whereas the thermal efficiency is around 4.5%. R1234ze is the best working fluid employing parabolic solar collectors (hot water temperature equal...

  19. 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

    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...... 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...

  20. 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...

  1. 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

    %) 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......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...

  2. Theoretical and experimental research of organic Rankine cycle steam turbine plants

    Science.gov (United States)

    Kishkin, A. A.; Delkov, A. V.; Melkozerov, M. G.

    2017-10-01

    Currently steam power cycles using organic actuation fluid - Freon, ammonia, ethanol, isobutene, etc are becoming increasingly important. Such cycles are called Organic Rankine Cycle (ORC). With the help of such cycles it is possible to use low-grade heat sources in the production of mechanical and electrical energy.

  3. 2013 MDEQ-FEMA Rankin-Simpson Co. Lidar Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fugro as a subconsultant to MGI was authorized to undertake this project, as a part of Work Order No. 112, dated November 1, 2012, issued to MGI in accordance with...

  4. 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.

  5. The Impact of Commercial Health Plan Prior Authorization Programs on the Utilization of Services for Low Back Pain

    Science.gov (United States)

    Goodman, Robert M.; Powell, Corey C.; Park, Paul

    2016-01-01

    Study Design. An observational study. Objective. The aim of this study was to evaluate the impact of a health plan's prior authorization (PA) programs for low back pain (LBP) in a non-Medicare population by assessing changes in pre-surgical nonoperative care; lumbar fusion trends; and overall back surgery rates compared with another health plan with a similar program and national benchmarks. The PA programs require mandatory physiatrist consultation before surgical evaluation, with subsequent additional LBP surgery PA. Summary of Background Data. LBP is prevalent and concern exists that spinal fusion is overutilized for LBP. Methods. Annual rates of lumbar fusion trended over 6 years, and analysis of changes in standardized costs for LBP-related services among a 501-member subset who underwent lumbar fusion before and after program implementations, during the period January 1, 2008, through December 31, 2013, among commercial members aged 18 and 65 years enrolled in a health maintenance organization with commercial membership averaging >500,000 annually. Results. After initiation of the physiatrist PA in December 2010, lumbar fusions decreased from 76.27/100,000 in 2010 to 62.63/100,000 in 2011 with subsequent increases to 64.24/100,000 and 73.84/100,000 in years 2012 and 2013. For members who had lumbar fusion, per-member, pre-surgical costs increased by $2,233 with the physiatrist PA and an additional $1,370 with implementation of the LBP surgery PA (March 2013). Spinal injections and inpatient admissions were the greatest contributors to the overall increase in costs. The physiatrist and LBP surgery PA programs were also associated with lengthening of LBP episodes ending in surgery by 309 and 198 days. Conclusion. Mandatory referral to a physiatrist before surgical evaluation did not result in persistent reduction in lumbar fusions. Instead, these programs were associated with the unintended consequence of increased costs from more nonoperative care for only a

  6. Organic Rankine Cycle and its application in renewable power engineering

    Directory of Open Access Journals (Sweden)

    G. V. Belov

    2014-01-01

    Full Text Available A considerable part of energy consumed in the world is thermal power that is produced due to burning of hydrocarbon fuels and as a result of controlled course of nuclear reactions. Thus rather large part of thermal power is used ultrainefficiently, often simply dissipates in environment. The rise in prices for energy compels to use low-grade one to be released in large quantities in environment. To utilize the low-grade energy Renkin's cycle with with alternative working bodies is often applied. The corresponding cycle was called Renkin's organic cycle (ROC. A substance with lower boiling temperature, than that of water is used in ROC as a working body to utilize low-grade energy.The review of literature shows that thrust on power sector related to utilization of residual heat (thermal waste and use of alternative energy sources, recently, intensively develops. However there is, essentially, a lack of publications on this subject in Russian. The objective of given article is to analyse modern sources of information (mainly, foreign ones which consider various aspects of ROC and its application potential in alternative power engineering. The article focuses much attention on the choice of ROC working body. It presents a list of main requirements for a working body. The article studies the matters of ROC simulation.It is shown that ROC application enables using the low-grade power of exhaust gases, geothermal sources, other thermal streams with rather low temperature. Integration of ROC with ICE (internal combustion engine is in position to increase an efficiency of used fuel energy and to reduce amount of toxic impurity in exhaust gases. Essential influence of working body properties on its characteristics of ROC is noted.

  7. 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......, 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...

  8. Prospects of the use of nanofluids as working fluids for organic Rankine cycle power systems

    DEFF Research Database (Denmark)

    Mondejar, Maria E.; Andreasen, Jesper G.; Regidor, Maria

    2017-01-01

    The search of novel working fluids for organic Rankine cycle power systems is driven by the recent regulations imposing additional phase-out schedules for substances with adverse environmental characteristics. Recently, nanofluids (i.e. colloidal suspensions of nanoparticles in fluids) have been...... suggested as potential working fluids for organic Rankine cycle power systems due to their enhanced thermal properties, potentially giving advantages with respect to the design of the components and the cycle performance. Nevertheless, a number of challenges concerning the use of nanofluids must...... be investigated prior to their practical use. Among other things, the trade-off between enhanced heat transfer and increased pressure drop in heat exchangers, and the impact of the nanoparticles on the working fluid thermophysical properties, must be carefully analyzed. This paper is aimed at evaluating...

  9. 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......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...

  10. Economic analysis of a dish-Rankine solar thermal power system

    Science.gov (United States)

    Pons, R. L.; Irwin, R. E.

    An analysis of the performance and costs of a first generation dish Rankine solar thermal power system for small community and industrial applications is presented. The system is of the point-focusing distributed receiver type, with distributed generation and employs multiple paraboloidal concentrators with organic Rankine cycle power conversion systems at the focus of each dish. Projected life cycle energy costs for a fully developed and mass produced system are shown to be competitive with costs projected in the near future for electricity generated by more conventional means. It is shown that: (1) the method of rating plant poer output has a minor influence on life cycle energy cost, (2) optimum dish size is greater than 12m, (3) energy cost is virtually independent of plant size above 1 MW sub e and (4) dish spacing and geometric arrangement can be optimized to reduce energy cost.

  11. 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...

  12. 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

    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......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...... turbine design model, the details of the validation and a sensitivity analysis on the main parameters, in order to minimize the number of decision variables in the subsequent turbine design optimization. Part B analyzes the application of the combined turbine and cycle designs on a selected case study...

  13. Study of toluene stability for an Organic Rankine Cycle (ORC) space-based power system

    Science.gov (United States)

    Havens, Vance; Ragaller, Dana

    1988-01-01

    The design, fabrication, assembly, and endurance operation of a dynamic test loop, built to evaluate the thermal stability of a proposed Organic Rankine Cycle (ORC) working fluid, is discussed. The test fluid, toluene, was circulated through a heater, simulated turbine, regenerator, condenser and pump to duplicate an actual ORC system. The maximum nominal fluid temperature, 750 F, was at the turbine simulator inlet. Samples of noncondensible gases and liquid toluene were taken periodically during the test. The samples were analyzed to identify the degradation products formed and the quantity of these products. From these data it was possible to determine the degradation rate of the working fluid and the generation rate of noncondensible gases. A further goal of this work was to relate the degradation observed in the dynamic operating loop to degradation obtained in isothermal capsule tests. This relationship was the basis for estimating the power loop degradation in the Space Station Organic Rankine Cycle system.

  14. 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

    emphasis on compactness and reliability. In such context, organic Rankine cycle turbogenerators are a promising technology. The implementation of an organic Rankine cycle unit is thus considered for the power system of the Draugen offshore platform in the northern sea, which is the case study......This work relates to a project focusing on energy optimization on offshore facilities. On oil and gas platforms it is common practice to employ gas turbines for power production. So as to increase the system performance and reduce emissions, a bottoming cycle unit can be designed with particular...... 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...

  15. 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%.

  16. System and method for regulating EGR cooling using a Rankine cycle

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, Timothy C.; Morris, Dave

    2017-08-29

    This disclosure relates to a waste heat recovery (WHR) system and method for regulating exhaust gas recirculation (EGR) cooling, and more particularly, to a Rankine cycle WHR system and method, including a recuperator bypass arrangement to regulate EGR exhaust gas cooling for engine efficiency improvement and thermal management. This disclosure describes other unique bypass arrangements for increased flexibility in the ability to regulate EGR exhaust gas cooling.

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

    OpenAIRE

    Ratha Z. Mathkor; Brian Agnew; Mohammed A. Al-Weshahi; Fathi Latrsh

    2015-01-01

    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, distille...

  18. 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 ...

  19. 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 ...

  20. Autonomous low-temperature solar Rankine cycle system for reverse osmosis desalination

    Energy Technology Data Exchange (ETDEWEB)

    Manolakos, D.; Makris, G.; Papadakis, G.; Kyritsis, S. [Agricultural University of Athens (Greece). Dept. of Agricultural Engineering; Bouzianas, K. [Hellas Energy K. Bouzianas P. Moschovitis and Co., Athens (Greece)

    2004-07-01

    The research regards the development, application testing and performance evaluation of a low temperature solar organic Rankine cycle system for Reverse Osmosis (RO) desalination. Below is given a technical description of the system under development: Thermal energy produced by the solar array evaporates the working fluid (HFC- 134a) in the evaporator surface. The super-heated vapour is driven to the expanders where the generated mechanical work produced by the Rankine cycle drives the RO unit pumps (high pressure pump, cooling water pump, feed water pump) and circulating pump. The saturated vapour at the expanders' outlet is directed to the condenser and condensates. On the condenser surface, seawater is pre-heated and directed to the seawater reservoir. Seawater pre-heating is applied to increase the fresh water recovery ratio. The seawater tank is insulated. The use of seawater on the condenser surface decreases the temperature of ''Low Temperature Reservoir'' of Rankine cycle thus a better cycle efficiency is achieved. For the prototype system 240 m2 of vacuum tube solar collectors will be deployed. The evaporator and condenser capacity is estimated to be about 100 kW. For these systems' characteristics and considering a water recovery ratio of seawater RO desalination unit of 30%, the average yearly fresh water production is estimated at 1450 m3 (or 4 m3 daily). Specific innovations of the system are: Low temperature thermal sources can be exploited efficiently for fresh water production; solar energy is used indirectly and does not heat the seawater; the RO unit is driven by mechanical work produced from the process; the system condenser acts as sea water pre-heater and this serves a double purpose; (1) increase of feed water temperature implies higher fresh water production (2) decrease of temperature of ''low temperature reservoir'' of Rankine cycle implies higher cycle efficiencies. (orig.)

  1. Optimisation robuste de turbines pour les cycles organiques de Rankine (ORC)

    OpenAIRE

    Bufi, Elio Antonio

    2016-01-01

    In recent years, the Organic Rankine Cycle (ORC) technology has received great interest from the scientific and technical community because of its capability to recover energy from low-grade heat sources. In some applications, as the Waste Heat Recovery (WHR), ORC plants need to be as compact as possible because of geometrical and weight constraints. Recently, these issues have been studied in order to promote the ORC technology for Internal Combustion Engine (ICE) applications. The idea to r...

  2. Thermodynamic Optimization of a Geothermal- Based Organic Rankine Cycle System Using an Artificial Bee Colony Algorithm

    OpenAIRE

    Osman Özkaraca; Pınar Keçebaş; Cihan Demircan; Ali Keçebaş

    2017-01-01

    Geothermal energy is a renewable form of energy, however due to misuse, processing and management issues, it is necessary to use the resource more efficiently. To increase energy efficiency, energy systems engineers carry out careful energy control studies and offer alternative solutions. With this aim, this study was conducted to improve the performance of a real operating air-cooled organic Rankine cycle binary geothermal power plant (GPP) and its components in the aspects of thermodynamic ...

  3. SORCE: A design tool for solar organic Rankine cycle systems in distributed generation applications

    OpenAIRE

    Orosz, Matthew; Quoilin, Sylvain; Hemond, Harold

    2010-01-01

    Recent interest in small-scale solar thermal combined heat and power (CHP) power systems has coincided with demand growth for distributed electricity supplies in areas poorly served by centralized power stations. One potential technical approach to meeting this demand is the parabolic trough solar thermal collector coupled with an organic Rankine cycle (ORC) heat engine. Much existing research touches on aspects of the underlying physics and mechanics of this technology, but a holistic treatm...

  4. Thermodynamic Analysis of a Rankine Cycle Powered Vapor Compression Ice Maker Using Solar Energy

    OpenAIRE

    Bing Hu; Xianbiao Bu; Weibin Ma

    2014-01-01

    To develop the organic Rankine-vapor compression ice maker driven by solar energy, a thermodynamic model was developed and the effects of generation temperature, condensation temperature, and working fluid types on the system performance were analyzed. The results show that the cooling power per square meter collector and ice production per square meter collector per day depend largely on generation temperature and condensation temperature and they increase firstly and then decrease with incr...

  5. On the Rankin-Selberg method for higher genus string amplitudes

    CERN Document Server

    Florakis, Ioannis

    2017-01-01

    Closed string amplitudes at genus $h\\leq 3$ are given by integrals of Siegel modular functions on a fundamental domain of the Siegel upper half-plane. When the integrand is of rapid decay near the cusps, the integral can be computed by the Rankin-Selberg method, which consists of inserting an Eisenstein series $E_h(s)$ in the integrand, computing the integral by the orbit method, and finally extracting the residue at a suitable value of $s$. String amplitudes, however, typically involve integrands with polynomial or even exponential growth at the cusps, and a renormalization scheme is required to treat infrared divergences. Generalizing Zagier's extension of the Rankin-Selberg method at genus one, we develop the Rankin-Selberg method for Siegel modular functions of degree 2 and 3 with polynomial growth near the cusps. In particular, we show that the renormalized modular integral of the Siegel-Narain partition function of an even self-dual lattice of signature $(d,d)$ is proportional to a residue of the Langla...

  6. Thermodynamic Analysis of a Rankine Cycle Powered Vapor Compression Ice Maker Using Solar Energy

    Directory of Open Access Journals (Sweden)

    Bing Hu

    2014-01-01

    Full Text Available To develop the organic Rankine-vapor compression ice maker driven by solar energy, a thermodynamic model was developed and the effects of generation temperature, condensation temperature, and working fluid types on the system performance were analyzed. The results show that the cooling power per square meter collector and ice production per square meter collector per day depend largely on generation temperature and condensation temperature and they increase firstly and then decrease with increasing generation temperature. For every working fluid there is an optimal generation temperature at which organic Rankine efficiency achieves the maximum value. The cooling power per square meter collector and ice production per square meter collector per day are, respectively, 126.44 W m−2 and 7.61 kg m−2 day−1 at the generation temperature of 140°C for working fluid of R245fa, which demonstrates the feasibility of organic Rankine cycle powered vapor compression ice maker.

  7. 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.

  8. 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.

  9. Economic, Energetic, and Environmental Performance of a Solar Powered Organic Rankine Cycle with Electric Energy Storage in Different Commercial Buildings

    Directory of Open Access Journals (Sweden)

    Emily Spayde

    2018-01-01

    Full Text Available This paper presents an analysis to determine the economic, energetic, and environmental benefits that could be obtained from the implementation of a combined solar-power organic Rankine cycle (ORC with electric energy storage (EES to supply electricity to several commercial buildings including a large office, a small office, and a full service restaurant. The operational strategy for the ORC-EES system consists in the ORC charging the EES when the irradiation level is sufficient to generate power, and the EES providing electricity to the building when there is not irradiation (i.e., during night time. Electricity is purchased from the utility grid unless it is provided by the EES. The potential of the proposed system to reduce primary energy consumption (PEC, carbon dioxide emission (CDE, and cost was evaluated. Furthermore, the available capital cost for a variable payback period for the ORC-EES system was determined for each of the evaluated buildings. The effect of the number of solar collectors on the performance of the ORC-EES is also studied. Results indicate that the proposed ORC-EES system is able to satisfy 11%, 13%, and 18% of the electrical demand for the large office, the small office and the restaurant, respectively.

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

    Energy Technology Data Exchange (ETDEWEB)

    Al-Sulaiman, Fahad A. [Mechanical and Aerospace Engineering Department, Carleton University 1125 Colonel By Drive, Ottawa, Ontario (Canada); Dincer, Ibrahim [Faculty of Engineering and Applied Science, University of Ontario Institute of Technology 2000 Simcoe Street North, Oshawa, Ontario (Canada); Hamdullahpur, Feridun [Mechanical and Mechatronics Engineering Department, University of Waterloo, 200 University Avenue West, Waterloo, Ontario (Canada)

    2010-04-15

    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. (author)

  11. Moteurs composites à allumage par compression et cycle de Rankine Dual Fuel Compression Ignition Engines Operating on the Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Daugas C.

    2006-11-01

    Full Text Available Sur les 60 % de l'énergie introduite dans un groupe électrogène et perdue sous forme de chaleur, une bonne partie peut être utilisée pour fabriquer à nouveau de l'électricité à partir d'une turbine à vapeur. Les moteurs dual fuel brûlant essentiellement du gaz naturel sont remarquablement placés pour une telle récupération, dont le rendement est meilleur aux charges partielles que celui des moteurs diesel classiques. Les différents types de fluides utilisés pour la récupération sont examinés : avantages des fluides organiques sur l'eau. Études d'une réalisation concrète. Fonctionnement aux charges partielles. Influence des différents paramètres pour obtenir le meilleur rapport prix/puissance. Of the 60% of input energy lost in the form of heat in a generating set, a sizeable part can be used to generate electricity again by means of a steam turbine. Dual fuel engines which mainly burn natural gas are outstandingly suitable for such a recovery process, the efficiency under partial loads being better than that of conventional diesel engines. The author considers the different types of fluids used for the recovery process superiority of organic fluids over water. Study of a concrete example. Operation with partial loads. Influence of the different parameters in the quest for the best cost-power ratio.

  12. Experimental Comparison Of Working Fluids For Organic Rankine Cycle With Single-Screw Expander

    OpenAIRE

    Gusev, Sergei; Ziviani, Davide; Bell, Ian; De Paepe, Michel; van den Broek, Martijn

    2014-01-01

    This paper describes the behavior of an Organic Rankine Cycle (ORC) fed by a heat source with adaptable temperature and mass flow. For a suitable choice of working fluid, the setting of its evaporation pressure is crucial for the performance of an ORC installation. The higher the evaporation pressure, the higher the cycle efficiency on the one hand, but the lower the energy recovered from the heat source due to a higher outlet temperature on the other hand. An optimum has to be found to achie...

  13. Numerical Optimization of an Organic Rankine Cycle Scheme for Co-generation

    OpenAIRE

    Potenza, Marco; Naccarato, Fabrizio; Stigliano, Gianbattista; Risi, Arturo de

    2016-01-01

    The aim of the present work was the optimization of a small size Organic Rankine Cycle (ORC) system powered by a linear Parabolic Trough Collector (PTC) solar field by means of numerical model code developed on purpose. In the proposed scheme the solar energy is collected by a newly designed low cost PTC of 20m2 with a single tracking axis and it is concentrated on an opaque pipe collector in which flows as thermal fluid the Therminol® 66 oil. An oil-free scroll expander coupled with a 2 kW e...

  14. Theoretical study of thermally driven heat pumps based on double organic rankine cycle

    OpenAIRE

    Demierre, Jonathan; Favrat, Daniel

    2013-01-01

    Part of: Thermally driven heat pumps for heating and cooling. – Ed.: Annett Kühn – Berlin: Universitätsverlag der TU Berlin, 2013 ISBN 978-3-7983-2686-6 (print) ISBN 978-3-7983-2596-8 (online) urn:nbn:de:kobv:83-opus4-39458 [http://nbn-resolving.de/urn:nbn:de:kobv:83-opus4-39458] This study deals with a type of thermally driven heat pumps that consists of a reverse Rankine heat pump cycle, the compressor of which is driven by the turbine of a supercritical Organi...

  15. 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......) cubic EoS with perturbed-chain statistical associating fluid theory (PC-SAFT) EoS for anorganic Rankine cycle (ORC) for heat recovery to power fromthe exhaust gas of a marine diesel engineusing cyclopentane as working fluid. Uncertainties of the EoS input parameters including...

  16. Conceptual design and analysis of a Dish-Rankine solar thermal power system

    Science.gov (United States)

    Pons, R. L.

    1980-08-01

    A Point Focusing Distributed Receiver (PFDR) solar thermal electric system which employs small Organic Rankine Cycle (ORC) engines is examined with reference to its projected technical/economic performance. With mass-produced power modules (about 100,000 per year), the projected life-cycle energy cost for an optimized no-storage system is estimated at 67 mills/kWh (Levelized Busbar Energy Cost) without the need for advanced development of any of its components. At moderate production rates (about 50 MWe/yr) system energy costs are competitive with conventional power generation systems in special remote-site types of applications.

  17. Panel cutting method: new approach to generate panels on a hull in Rankine source potential approximation

    Directory of Open Access Journals (Sweden)

    Hee-Jong Choi

    2011-12-01

    Full Text Available In the present study, a new hull panel generation algorithm, namely panel cutting method, was developed to predict flow phenomena around a ship using the Rankine source potential based panel method, where the iterative method was used to satisfy the nonlinear free surface condition and the trim and sinkage of the ship was taken into account. Numerical computations were performed to investigate the validity of the proposed hull panel generation algorithm for Series 60 (CB=0.60 hull and KRISO container ship (KCS, a container ship designed by Maritime and Ocean Engineering Research Institute (MOERI. The computational results were validated by comparing with the existing experimental data.

  18. 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

    to improve the boiling process. Optimizations are carried out for eight hydrocarbon mixtures for hot fluid inlet temperatures at 120 °C and 90 °C, using a genetic algorithm to determine the cycle conditions for which the net power output is maximized. The most promising mixture is an isobutane....../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...

  19. Preliminary design package for residential heating/cooling system--Rankine air conditioner redesign

    Energy Technology Data Exchange (ETDEWEB)

    1978-12-01

    This report contains a summary of the preliminary redesign and development of a marketable single-family heating and cooling system. The objectives discussed are the interim design and schedule status of the Residential (3-ton) redesign, problem areas and solutions, and the definition of plans for future design and development activities. The proposed system for a single-family residential heating and cooling system is a single-loop, solar-assisted, hydronic-to-warm-air heating subsystem with solar-assisted domestic water heating and a Rankine-driven expansion air-conditioning subsystem.

  20. Author Details

    African Journals Online (AJOL)

    Odigie, IC. Vol 18, No 1-6 (2016) - Articles Vaccine Pharmacovigilance: Adverse Effects Reported and the Pattern of Vaccines Utilization in a Tertiary Institution, Nigeria. Abstract. ISSN: 1597-7889. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Kabonga, RM. Vol 37, No 4 (2010) - Articles Factors influencing utilization of Natural Family Planning among Child Bearing Women in Chilonga Northern Province Zambia Abstract PDF. ISSN: 0047-651X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about ...

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    Lawal, Zainab Iyabo. Vol 17, No 1 (2017) - Articles Utilization of physiotherapy in the continuum of stroke care at a tertiary hospital in Ibadan, Nigeria Abstract PDF. ISSN: 1680-6905. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners ...

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    Olaleye, Olubukola Adebisi. Vol 17, No 1 (2017) - Articles Utilization of physiotherapy in the continuum of stroke care at a tertiary hospital in Ibadan, Nigeria Abstract PDF. ISSN: 1680-6905. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ...

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    Økland, Finn. Vol 40, No 2 (2005) - Articles Movements and habitat utilization of nembwe, Serranochromis robustus (Günther, 1864), in the Upper Zambezi River Abstract. ISSN: 2224-073X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ...

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    Hoseini, S. Vol 8, No 3 (2016): Special Issue - Articles Design health village with the approach of sustainable architecture and utilization of intelligent principles. Abstract PDF. ISSN: 1112-9867. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Osegbue, AI. Vol 2, No 2 (2006) - Articles Evaluation of production parameters and nutrient utilization of hens fed rations containing Anthonata macrophyla seed meal. Abstract. ISSN: 0794-4721. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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  13. 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.

  14. 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$.

  15. 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.

  16. 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.

  17. 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...

  18. 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...... mixturesare usually degraded compared to an ideal mixture heat transfer coefficient linearly interpolatedbetween the pure fluid values. This entails a need for larger and more expensive heat exchangers. Previousstudies primarily focus on the thermodynamic benefits of zeotropic mixtures by employing firstand...... second law analyses. In order to assess the feasibility of using zeotropic mixtures, it is, however,important to consider the additional costs of the heat exchangers. In this study, we aim at evaluatingthe economic feasibility of zeotropic mixtures compared to pure fluids. We carry out a multi...

  19. 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

    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...... modeloutput, and provides the 95%-confidence interval of the net power output with respect to the fluid property uncertainties. The methodology has been applied to a molecular design problem for an ORCusing a low-temperature heat source and consisted of the following four parts: 1) formulation...... 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...

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

    Science.gov (United States)

    Liu, Yan-Na; Xiao, Song

    2015-06-01

    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.

  1. 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.

  2. 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.

  3. Draft report: application of organic Rankine cycle heat recovery systems to diesel powered marine vessels

    Energy Technology Data Exchange (ETDEWEB)

    1977-07-15

    The analysis and results of an investigation of the application of organic Rankine cycle heat recovery systems to diesel-powered marine vessels are described. The program under which this study was conducted was sponsored jointly by the US Energy Research and Development Administration, the US Navy, and the US Maritime Administration. The overall objective of this study was to investigate diesel bottoming energy recovery systems, currently under development by three US concerns, to determine the potential for application to marine diesel propulsion and auxiliary systems. The study primarily focused on identifying the most promising vessel applications (considering vessel type, size, population density, operational duty cycle, etc.) so the relative economic and fuel conservation merits of energy recovery systems could be determined and assessed. Vessels in the current fleet and the projected 1985 fleet rated at 1000 BHP class and above were investigated.

  4. 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.

  5. Rankine cycle condenser pressure control using an energy conversion device bypass valve

    Science.gov (United States)

    Ernst, Timothy C; Nelson, Christopher R; Zigan, James A

    2014-04-01

    The disclosure provides a waste heat recovery system and method in which pressure in a Rankine cycle (RC) system of the WHR system is regulated by diverting working fluid from entering an inlet of an energy conversion device of the RC system. In the system, an inlet of a controllable bypass valve is fluidly coupled to a working fluid path upstream of an energy conversion device of the RC system, and an outlet of the bypass valve is fluidly coupled to the working fluid path upstream of the condenser of the RC system such that working fluid passing through the bypass valve bypasses the energy conversion device and increases the pressure in a condenser. A controller determines the temperature and pressure of the working fluid and controls the bypass valve to regulate pressure in the condenser.

  6. Control system to a Rankine cycle with a Tesla turbine using arduino

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Josenei G., E-mail: joseneigodoi@yahoo.com.br [Faculdade de Tecnologia Sao Francisco (FATESF), Jacarei, SP (Brazil); Guimaraes, Lamartine F.; Placco, Guilherme M., E-mail: guimarae@ieav.cta.br, E-mail: placco@ieav.cta.br [Instituto de Estudos Avancados (ENU/IEAv/DCTA), Sao Jose dos Campos, SP (Brazil). Departamento de Energia Nuclear

    2013-07-01

    The thermal Rankine cycle is a thermodynamic cycle which converts heat in energy. This cycle occurs in steady state, in other words the cycle is a closed loop circuit with continuous feedback, which guarantees the reuse process one energy transformed in the various stages of the cycle. This cycle is used to drive a turbine type TESLA designed for the system. The objective of this work is to create the control and automation of this cycle using an micro-controlled system with Arduino that will hold the collection of sensors and the system will act to maintain the balance of the cycle causing it to behave continuously and with less interference from human operation for maintenance. Data will be collected and further processed, where it will display all the sensors and the situation of the actuators involved. Using Arduino system ensures the stability and reliability with a low cost of implementation.

  7. Thermodynamic Analysis of an Integrated Solid Oxide Fuel Cell Cycle with a Rankine Cycle

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2010-01-01

    Hybrid systems consisting of Solid Oxide Fuel Cells (SOFC) on the top of a Steam Turbine (ST) are investigated. The plants are fired by natural gas (NG). A desulfurization reactor removes the sulfur content in the fuel while a pre-reformer breaks down the heavier hydrocarbons. The pre-treated fuel...... enters then into the anode side of the SOFC. The remaining fuels after the SOFC stacks enter a burner for further burning. The off-gases are then used to produce steam for a Rankine cycle in a Heat Recovery Steam Generator (HRSG). Different system setups are suggested. Cyclic efficiencies up to 67......% are achieved which is considerably higher than the conventional Combined Cycles (CC). Both ASR (Adiabatic Steam Reformer) and CPO (Catalytic Partial Oxidation) fuel pre-reformer reactors are considered in this investigation....

  8. Computer modeling of a regenerative solar-assisted Rankine power cycle

    Science.gov (United States)

    Lansing, F. L.

    1977-01-01

    A detailed interpretation of the computer program that describes the performance of one of these cycles; namely, a regenerative Rankine power cycle is presented. Water is used as the working medium throughout the cycle. The solar energy collected at relatively low temperature level presents 75 to 80% of the total heat demand and provides mainly the latent heat of vaporization. Another energy source at high temperature level superheats the steam and supplements the solar energy share. A program summary and a numerical example showing the sequency of computations are included. The outcome from the model comprises line temperatures, component heat rates, specific steam consumption, percentage of solar energy contribution, and the overall thermal efficiency.

  9. 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.

  10. Utilization of low temperature heat for environmentally friendly electricity production

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Elmegaard, Brian; Haglind, Fredrik

    2014-01-01

    The focus on reduction of fossil fuelled electricity generation has increased the attention on exploitation of low grade heat as the energy source for electricity producing power plants. Low grade heat is heat, which isavailable at a low temperature, e.g. from waste heat from marine diesel engines...... and industrial processes orfrom geothermal and solar heat sources. Utilization of such heat sources makes it possible to produce electricity with no additional burning of fossil fuel, and does therefore represent an environmentally friendly alternative to fossil fuel based electricity production. Utilization...... of low grade heat is not feasible with conventional steam Rankine cycles (steam engines) due to undesirable properties of steam. Instead the organic Rankine cycle is typically used, since it enables thechoice of a working fluid, e.g. hydrocarbons or refrigerants, with desirable properties. One of the key...

  11. Radial turbine expander design for organic rankine cycle, waste heat recovery in high efficiency, off-highway vehicles

    OpenAIRE

    Alshammari, F.; Karvountzis-Kontakiotis, A; Pesiridis, A

    2016-01-01

    Although state-of-the-art, heavy duty diesel engines of today can reach peak thermal efficiencies of approximately 45%, still most of the fuel energy is transformed into wasted heat in the internal combustion process. Recovering this wasted energy could increase the overall thermal efficiency of the engine as well as reduce the exhaust gas emissions. Compared to other Waste Heat Recovery (WHR) technologies, Organic Rankine Cycle (ORC) systems are regarded favourably due to their relative simp...

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

    OpenAIRE

    Leonardo Pierobon; Tuong-Van Nguyen; Andrea Mazzucco; Ulrik Larsen; Fredrik Haglind

    2014-01-01

    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 worki...

  13. Modelling of organic Rankine cycle power systems in off-design conditions: an experimentally-validated comparative study

    OpenAIRE

    Dickes, Rémi; Dumont, Olivier; Daccord, Rémi; Quoilin, Sylvain; Lemort, Vincent

    2017-01-01

    Because of environmental issues and the depletion of fossil fuels, the world energy sector is undergoing many changes toward increased sustainability. Among the many fields of research and development, power generation from low-grade heat sources is gaining interest and the organic Rankine cycle (ORC) is seen as one of the most promising technologies for such applications. In this paper, it is proposed to perform an experimentally-validated comparison of different modelling methods for the of...

  14. Bayesian Zero-Failure (BAZE) reliability demonstration testing procedure and its application to a Rankine dynamic radioisotope power conversion system

    Energy Technology Data Exchange (ETDEWEB)

    Martz, H.F. Jr.; Waller, R.A.

    1976-07-01

    A Bayesian Zero-Failure (BAZE) reliability demonstration testing procedure is developed. The procedure may be used to verify component failure rates associated with both real-time dependent and cycle-dependent chance failure mechanisms. A constant falure-rate model with a gamma prior distribution is assumed. The procedure is used to obtain sample test plans for components of a proposed Rankine power conversion system.

  15. Test results of an organic Rankine-cycle power module for a small community solar thermal power experiment

    Science.gov (United States)

    Clark, T. B.

    1985-01-01

    The organic Rankine-cycle (ORC) power conversion assembly was tested. Qualification testing of the electrical transport subsystem was also completed. Test objectives were to verify compatibility of all system elements with emphasis on control of the power conversion assembly, to evaluate the performance and efficiency of the components, and to validate operating procedures. After 34 hours of power generation under a wide range of conditions, the net module efficiency exceeded 18% after accounting for all parasitic losses.

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

    OpenAIRE

    Theresa Weith; Florian Heberle; Markus Preißinger; Dieter Brüggemann

    2014-01-01

    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...

  17. Organic Rankine cycle – review and research directions in engine applications

    Directory of Open Access Journals (Sweden)

    Panesar Angad

    2017-01-01

    Full Text Available Waste heat to power conversion using Organic Rankine Cycles (ORC is expected to play an important role in CO2 reductions from diesel engines. Firstly, a review of automotive ORCs is presented focusing on the pure working fluids, thermal architectures and expanders. The discussion includes, but is not limited to: R245fa, ethanol and water as fluids; series, parallel and cascade as architectures; dry saturated, superheated and supercritical as expansion conditions; and scroll, radial turbine and piston as expansion machines. Secondly, research direction in versatile expander and holistic architecture (NOx + CO2 are proposed. Benefits of using the proposed unconventional approaches are quantified using Ricardo Wave and Aspen HYSYS for diesel engine and ORC modelling. Results indicate that, the implementation of versatile piston expander tolerant to two-phase and using cyclopentane can potentially increase the highway drive cycle power by 8%. Furthermore, holistic architecture offering complete utilisation of charge air and exhaust recirculation heat increased the performance noticeably to 5% of engine power at the design point condition.

  18. Organic Rankine kilowatt isotope power system. First annual summary report, August 1, 1975--August 1, 1976

    Energy Technology Data Exchange (ETDEWEB)

    1976-01-01

    Sundstrand Energy Systems is developing a Kilowatt Isotope Power System (KIPS) directed toward satisfying the higher power requirements of satellites of the 1980's. The KIPS is a plutonium oxide fueled organic Rankine cycle turbine power system which will provide design output power in the range of 500 to 2000 W(e) with a minimum of system changes. Research progress is reported on Phase I comprising: (1) flight system conceptual design and ground demonstration; (2) flight system design and ground qualification; and (3) flight system production, acceptance testing and delivery. The principal objectives of Phase I are to: (1) conceptually design the flight system, (2) based on the flight system concept, design and build the ground demonstration system (GDS), (3) conduct performance and endurance testing using electric heaters to simulate the radioisotope heat source, (4) identify and initiate long lead development efforts required to achieve the initial flight qualification hardware availability date of April 1981, and (5) finalize the flight concept design and prepare the program plan for the Phase II effort.

  19. Numerical computation of motions and structural loads for large containership using 3D Rankine panel method

    Science.gov (United States)

    Kim, Jung-Hyun; Kim, Yonghwan

    2017-12-01

    In this paper, we present the results of our numerical seakeeping analyses of a 6750-TEU containership, which were subjected to the benchmark test of the 2nd ITTC-ISSC Joint Workshop held in 2014. We performed the seakeeping analyses using three different methods based on a 3D Rankine panel method, including 1) a rigid-body solver, 2) a flexible-body solver using a beam model, and 3) a flexible-body solver using the eigenvectors of a 3D Finite Element Model (FEM). The flexible-body solvers adopt a fully coupled approach between the fluid and structure. We consider the nonlinear Froude-Krylov and restoring forces using a weakly nonlinear approach. In addition, we calculate the slamming loads on the bow flare and stern using a 2D generalized Wagner model. We compare the numerical and experimental results in terms of the linear response, the time series of the nonlinear response, and the longitudinal distribution of the sagging and hogging moments. The flexible-body solvers show good agreement with the experimental model with respect to both the linear and nonlinear results, including the high-frequency oscillations due to springing and whipping vibrations. The rigid-body solver gives similar results except for the springing and whipping.

  20. 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.

  1. Dynamic Simulation of an Organic Rankine Cycle—Detailed Model of a Kettle Boiler

    Directory of Open Access Journals (Sweden)

    Roberto Pili

    2017-04-01

    Full Text Available Organic Rankine Cycles (ORCs are nowadays a valuable technology to produce electricity from low and medium temperature heat sources, e.g., in geothermal, biomass and waste heat recovery applications. Dynamic simulations can help improve the flexibility and operation of such plants, and guarantee a better economic performance. In this work, a dynamic model for a multi-pass kettle evaporator of a geothermal ORC power plant has been developed and its dynamics have been validated against measured data. The model combines the finite volume approach on the tube side and a two-volume cavity on the shell side. To validate the dynamic model, a positive and a negative step function in heat source flow rate is applied. The simulation model performed well in both cases. The liquid level appeared the most challenging quantity to simulate. A better agreement in temperature was achieved by increasing the volume flow rate of the geothermal brine by 2% over the entire simulation. Measurement errors, discrepancies in working fluid and thermal brine properties and uncertainties in heat transfer correlations can account for this. In the future, the entire geothermal power plant will be simulated, and suggestions to improve its dynamics and control by means of simulations will be provided.

  2. 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

    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...... 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...... of the year in the Modelica language. A peak of 3.28 kW of power is reached in ORC mode with a heat input of 59.5 kW from the solar roof (23.9 kWh are produced during a typical summer day). In a representative winter day, 17.28 kWh are consumed by the heat pump with a daily average COP of 4.1. Conclusions...

  3. Comparison of different iterative schemes for ISPH based on Rankine source solution

    Directory of Open Access Journals (Sweden)

    Xing Zheng

    2017-07-01

    Full Text Available Smoothed Particle Hydrodynamics (SPH method has a good adaptability for the simulation of free surface flow problems. There are two forms of SPH. One is weak compressible SPH and the other one is incompressible SPH (ISPH. Compared with the former one, ISPH method performs better in many cases. ISPH based on Rankine source solution can perform better than traditional ISPH, as it can use larger stepping length by avoiding the second order derivative in pressure Poisson equation. However, ISPH_R method needs to solve the sparse linear matrix for pressure Poisson equation, which is one of the most expensive parts during one time stepping calculation. Iterative methods are normally used for solving Poisson equation with large particle numbers. However, there are many iterative methods available and the question for using which one is still open. In this paper, three iterative methods, CGS, Bi-CGstab and GMRES are compared, which are suitable and typical for large unsymmetrical sparse matrix solutions. According to the numerical tests on different cases, still water test, dam breaking, violent tank sloshing, solitary wave slamming, the GMRES method is more efficient than CGS and Bi-CGstab for ISPH method.

  4. Organic Rankine-cycle power systems working fluids study: Topical report No. 2, Toluene

    Energy Technology Data Exchange (ETDEWEB)

    Cole, R.L.; Demirgian, J.C.; Allen, J.W.

    1987-02-01

    The US Department of Energy initiated an investigation at Argonne National Laboratory in 1982 to experimentally determine the thermal stability limits and degradation rates of toluene as a function of maximum cycle temperature. Following the design and construction of a dynamic test loop capable of closely simulating the thermodynamic conditions of typical organic Rankine-cycle (ORC) power systems, four test runs, totaling about 3900 h of test time and covering a temperature range of 600-677(degree)F, were completed. Both liquid and noncondensable-vapor (gaseous) samples were drawn periodically and analyzed using capillary-column gas chromatography, gas chromatography/mass spectrometry, and mass spectrometry. A computer program that can predict degradation in an ORC engine was developed. Experimental results indicate that, if oxygen can be excluded from the system, toluene is a stable fluid up to the maximum test temperature; the charge of toluene could be used for several years before replacement became necessary. (Additional data provided by Sundstrand Corp. from tests sponsored by the National Aeronautics and Space Administration indicate that toluene may be used at temperatures up to 750(degree)F.) Degradation products are benign; the main liquid degradation products are bibenzyls, and the main gaseous degradation products are hydrogen and methane. A cold trap to remove gaseous degradation products from the condenser is necessary for extended operation. 21 figs., 22 tabs.

  5. 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.

  6. 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.

  7. 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.

  8. Reciprocating Expander for an Exhaust Heat Recovery Rankine Cycle for a Passenger Car Application

    Directory of Open Access Journals (Sweden)

    Osoko Shonda

    2012-06-01

    Full Text Available Nowadays, on average, two thirds of the fuel energy consumed by an engine is wasted through the exhaust gases and the cooling liquid. The recovery of this energy would enable a substantial reduction in fuel consumption. One solution is to integrate a heat recovery system based on a steam Rankine cycle. The key component in such a system is the expander, which has a strong impact on the system’s performance. A survey of different expander technologies leads us to select the reciprocating expander as the most promising one for an automotive application. This paper therefore proposes a steady-state semi-empirical model of the expander device developed under the Engineering Equation Solver (EES environment. The ambient and mechanical losses as well as internal leakage were taken into account by the model. By exploiting the expander manufacturer’s data, all the parameters of the expander model were identified. The model computes the mass flow rate, the power output delivered and the exhaust enthalpy of the steam. The maximum deviation between predictions and measurement data is 4.7%. A performance study of the expander is carried out and shows that the isentropic efficiency is quite high and increases with the expander rotary speed. The mechanical efficiency depends on mechanical losses which are quite high, approximately 90%. The volumetric efficiency was also evaluated.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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......Wh/year and total electrical consumption of 2318 kWh/year) with a 138.8 m2 solar roof in Denmark....

  14. Alkali Metal Rankine Cycle Boiler Technology Challenges and Some Potential Solutions for Space Nuclear Power and Propulsion Applications

    Science.gov (United States)

    Stone, James R.

    1994-01-01

    Alkali metal boilers are of interest for application to future space Rankine cycle power conversion systems. Significant progress on such boilers was accomplished in the 1960's and early 1970's, but development was not continued to operational systems since NASA's plans for future space missions were drastically curtailed in the early 1970's. In particular, piloted Mars missions were indefinitely deferred. With the announcement of the Space Exploration Initiative (SEI) in July 1989 by President Bush, interest was rekindled in challenging space missions and, consequently in space nuclear power and propulsion. Nuclear electric propulsion (NEP) and nuclear thermal propulsion (NTP) were proposed for interplanetary space vehicles, particularly for Mars missions. The potassium Rankine power conversion cycle became of interest to provide electric power for NEP vehicles and for 'dual-mode' NTP vehicles, where the same reactor could be used directly for propulsion and (with an additional coolant loop) for power. Although the boiler is not a major contributor to system mass, it is of critical importance because of its interaction with the rest of the power conversion system; it can cause problems for other components such as excess liquid droplets entering the turbine, thereby reducing its life, or more critically, it can drive instabilities-some severe enough to cause system failure. Funding for the SEI and its associated technology program from 1990 to 1993 was not sufficient to support significant new work on Rankine cycle boilers for space applications. In Fiscal Year 1994, funding for these challenging missions and technologies has again been curtailed, and planning for the future is very uncertain. The purpose of this paper is to review the technologies developed in the 1960's and 1970's in the light of the recent SEI applications. In this way, future Rankine cycle boiler programs may be conducted most efficiently. This report is aimed at evaluating alkali metal boiler

  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. Waste Heat-to-Power Using Scroll Expander for Organic Rankine Bottoming Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Dieckmann, John [TIAX LLC, Lexington, MA (United States); Smutzer, Chad [TIAX LLC, Lexington, MA (United States); Sinha, Jayanti [TIAX LLC, Lexington, MA (United States)

    2017-05-30

    The objective of this program was to develop a novel, scalable scroll expander for conversion of waste heat to power; this was accomplished and demonstrated in both a bench-scale system as well as a full-scale system. The expander is a key component in Organic Rankine Cycle (ORC) waste heat recovery systems which are used to convert medium-grade waste heat to electric power in a wide range of industries. These types of waste heat recovery systems allow for the capture of energy that would otherwise just be exhausted to the atmosphere. A scroll expander has the benefit over other technologies of having high efficiency over a broad range of operating conditions. The speed range of the TIAX expander (1,200 to 3,600 RPM) enables the shaft power output to directly drive an electric generator and produce 60 Hz electric power without incurring the equipment costs or losses of electronic power conversion. This greatly simplifies integration with the plant electric infrastructure. The TIAX scroll expander will reduce the size, cost, and complexity of a small-scale waste heat recovery system, while increasing the system efficiency compared to the prevailing ORC technologies at similar scale. During this project, TIAX demonstrated the scroll expander in a bench-scale test setup to have isentropic efficiency of 70-75% and operated it successfully for ~200 hours with minimal wear. This same expander was then installed in a complete ORC system driven by a medium grade waste heat source to generate 5-7 kW of electrical power. Due to funding constraints, TIAX was unable to complete this phase of testing, although the initial results were promising and demonstrated the potential of the technology.

  17. 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.

  18. Thermo-Economic Performance Analysis of a Regenerative Superheating Organic Rankine Cycle for Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    Zhonghe Han

    2017-10-01

    Full Text Available The Organic Rankine Cycle (ORC is a promising form of technology for recovering low-grade waste heat. In this study, a regenerative ORC system is established to recover the waste flue gas of 160 °C. Focusing on thermodynamic and economic performance while simultaneously considering the limitations of volume flow ratio (VFR and the effect of superheat, working fluid selection and parameter optimization have been investigated. The optimization of the evaporation temperature is carried out by analyzing the variation of net power output and specific investment cost (SIC. Then, the net power output, specific net power output, total exergy destruction rate, VFR, total capital cost, and levelized electricity cost (LEC are selected as criteria, and a fuzzy multi-criteria evaluation method is adopted to select a more suitable working fluid and determine the optimal degree of superheat. In addition, the preheating coefficient, latent heat coefficient, superheating coefficient, and internal heat coefficient were proposed to explore the effect of working fluid critical temperature on thermal efficiency. Research studies demonstrate that there is an optimal evaporation temperature, maximizing net power output and minimizing the SIC. Isohexane and butane have greater specific net power output due to greater latent heat. A suitable degree of superheat is not only conducive to improving the working capacity of working fluids, but also reduces the VFR, total capital cost, SIC, and LEC for different working fluids. Thus, the system’s thermodynamic and economic performance—as well as the operational stability—are improved. Among the six working fluids, butane exhibits the best comprehensive performance, and its optimal evaporation temperature and degree of superheat are 100 °C and 5 °C, respectively.

  19. Applied studies in advanced boiler technology for Rankine cycle power systems

    Energy Technology Data Exchange (ETDEWEB)

    Paul, F.W.; Negreanu, M.J.

    1978-02-01

    A study is presented on a new rotational boiler design which has improved passive dynamic response and two-phase flow stability characteristics. A survey of small boiler manufacturers in the United States indicated that currently available designs are based on steady-state operating requirements rather than for dynamic performance. Recent work by EPA and ERDA which addressed boiler designs for mobile automotive Rankine cycle power systems showed that boilers of a monotube or multipass tube configuration design could be developed which were physically compact, but still were subject to the two-phase flow instability problem when coupled within an operating power system. The objectives of this work were to evaluate alternative boiler configurations which would improve boiler dynamic response and also have good two-phase liquid-vapor interface flow stability. The major physical design limitation of any boiler is the small external hot gas heat transfer coefficient. Such a low coefficient requires considerable design enhancements to increase the rate of energy transfer to the circulation system fluid. The rotational boiler is a physical design configuration which addresses this problem. The results of an analytic study using several mathematical model formulations showed that a rotational boiler could have a passive response time constant which was approximately one-half the magnitude for an equivalent single pass monotube boiler. An experimental prototype rotational boiler was designed, manufactured and tested, with the experimental results confirming that the experimental passive response time constants were comparable to the estimates from the analytic models. The experimental boiler operating in two-phase flow was found to be stable and responsive to external inputs. A rotational boiler configuration is a good alternative design configuration for small compact vapor generator designs based on fast transient passive response and two-phase flow stability.

  20. Thermodynamic Optimization of a Geothermal- Based Organic Rankine Cycle System Using an Artificial Bee Colony Algorithm

    Directory of Open Access Journals (Sweden)

    Osman Özkaraca

    2017-10-01

    Full Text Available Geothermal energy is a renewable form of energy, however due to misuse, processing and management issues, it is necessary to use the resource more efficiently. To increase energy efficiency, energy systems engineers carry out careful energy control studies and offer alternative solutions. With this aim, this study was conducted to improve the performance of a real operating air-cooled organic Rankine cycle binary geothermal power plant (GPP and its components in the aspects of thermodynamic modeling, exergy analysis and optimization processes. In-depth information is obtained about the exergy (maximum work a system can make, exergy losses and destruction at the power plant and its components. Thus the performance of the power plant may be predicted with reasonable accuracy and better understanding is gained for the physical process to be used in improving the performance of the power plant. The results of the exergy analysis show that total exergy production rate and exergy efficiency of the GPP are 21 MW and 14.52%, respectively, after removing parasitic loads. The highest amount of exergy destruction occurs, respectively, in condenser 2, vaporizer HH2, condenser 1, pumps 1 and 2 as components requiring priority performance improvement. To maximize the system exergy efficiency, the artificial bee colony (ABC is applied to the model that simulates the actual GPP. Under all the optimization conditions, the maximum exergy efficiency for the GPP and its components is obtained. Two of these conditions such as Case 4 related to the turbine and Case 12 related to the condenser have the best performance. As a result, the ABC optimization method provides better quality information than exergy analysis. Based on the guidance of this study, the performance of power plants based on geothermal energy and other energy resources may be improved.

  1. Author! Author! Beverly Cleary

    Science.gov (United States)

    Brodie, Carolyn S.

    2005-01-01

    This article presents a brief biography of author Beverly Cleary. Born on April 12, 1916 in McMinnville, Oregon (Yamhill County), Beverly Cleary celebrated her eighty-ninth birthday in 2005. Cleary is probably best known for creating "Ramona" and the other children's book characters who live on Klickitat Street in Portland, Oregon. A selective…

  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. Organic Rankine-Cycle Power Systems Working Fluids Study: Topical report No. 3, 2-methylpyridine/water

    Energy Technology Data Exchange (ETDEWEB)

    Cole, R.L.; Demirgian, J.C.; Allen, J.W.

    1987-09-01

    A mixture of 35 mole percent (mol %) 2-methylpyridine and 65 mol % water was tested at 575, 625, and 675/degree/F in a dynamic loop. Samples of the degraded fluid were chemically analyzed to determine the identities of major degradation products and the quantity of degradation. Computed degradation rates were found to be higher than those for Fluorinol 85 or toluene. For this reason (and other reasons, related to fluid handling), other fluids are recommended as the first choice for service in organic Rankine-cycle systems in preference to 2-methylpyridine/water. 7 refs., 39 figs., 39 tabs.

  4. 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...... 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...

  5. Experimental and thermodynamic analysis of a bottoming Organic Rankine Cycle (ORC) of gasoline engine using swash-plate expander

    OpenAIRE

    Galindo, José,; Ruiz Rosales, Santiago; Dolz Ruiz, Vicente; ROYO PASCUAL, LUCÍA; Haller, R.; Nicolas, B.; Glavatskaya, Y.

    2015-01-01

    This paper deals with the experimental testing of an Organic Rankine Cycle (ORC) integrate in a 2 liter turbocharged gasoline engine using ethanol as working fluid. The main components of the cycle are a boiler, a condenser, a pump and a swash-plate expander. Five engine operating points have been tested, they correspond to a nominal heat input into the boiler of 5, 12, 20, 25 and 30 kW. With the available bill of material based on prototypes, power balances and cycles efficiencies were estim...

  6. Development of an Organic Rankine-Cycle power module for a small community solar thermal power experiment

    Science.gov (United States)

    Kiceniuk, T.

    1985-01-01

    An organic Rankine-cycle (ORC) power module was developed for use in a multimodule solar power plant to be built and operated in a small community. Many successful components and subsystems, including the reciever, power conversion subsystem, energy transport subsystem, and control subsystem, were tested. Tests were performed on a complete power module using a test bed concentrator in place of the proposed concentrator. All major single-module program functional objectives were met and the multimodule operation presented no apparent problems. The hermetically sealed, self-contained, ORC power conversion unit subsequently successfully completed a 300-hour endurance run with no evidence of wear or operating problems.

  7. 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)

  8. Association between Cerebral Performance Category, Modified Rankin Scale, and discharge disposition after cardiac arrest.

    Science.gov (United States)

    Rittenberger, Jon C; Raina, Ketki; Holm, Margo B; Kim, Young Joo; Callaway, Clifton W

    2011-08-01

    Cerebral Performance Category (CPC), Modified Rankin Scale (mRS) and discharge disposition are commonly used to determine outcomes following cardiac arrest. This study tested the association between these outcome measures. Retrospective chart review of subjects who survived to hospital discharge between 1/1/2006 and 12/31/2009 was conducted. Charts were reviewed for outcomes (CPC, mRS, and discharge disposition). Discharge disposition was classified in 6 categories: home with no services, home with home healthcare, acute rehabilitation facility, skilled nursing facility, long term acute care facility, and hospice. Intra-and inter-rater reliabilities were calculated for outcome measures. Rates of "good outcome" (defined as a CPC of 1-2, mRS of 0-3, or discharge disposition to home or acute rehabilitation facility) were also determined. Kendall's tau correlation coefficients explored relationships among measures. A total of 211 charts were reviewed. Mean age was 60 years (SD 16), the majority (75%) were white males, in- and out-of hospital cardiac arrests were equally prevalent, and ventricular dysrhythmia was most common (N=109, 52%). Half of the subjects were comatose following resuscitation and 75 (35%) received therapeutic hypothermia. Inter-rater percentage agreement for CPC and mRS abstraction was 95.24% (kappa 0.89, pdefinition, 47 subjects (22%) using the mRS definition, and 129 subjects (61%) subjects using discharge disposition definition. There was fair relationship between the CPC and mRS (tau 0.43) and poor relationships between CPC and discharge disposition (tau 0.23) and between mRS and discharge disposition (tau 0.25). Determination of the CPC, mRS and discharge disposition at hospital discharge is reliable from chart review. These instruments provide widely differing estimates of "good outcome". Agreement between these measures ranges from poor to fair. A more nuanced outcome measure designed for the post-cardiac arrest population is needed

  9. Thermal energy storage for low grade heat in the organic Rankine cycle

    Science.gov (United States)

    Soda, Michael John

    Limits of efficiencies cause immense amounts of thermal energy in the form of waste heat to be vented to the atmosphere. Up to 60% of unrecovered waste heat is classified as low or ultra-low quality, making recovery difficult or inefficient. The organic Rankine cycle can be used to generate mechanical power and electricity from these low temperatures where other thermal cycles are impractical. A variety of organic working fluids are available to optimize the ORC for any target temperature range. San Diego State University has one such experimental ORC using R245fa, and has been experimenting with multiple expanders. One limitation of recovering waste heat is the sporadic or cyclical nature common to its production. This inconsistency makes sizing heat recovery ORC systems difficult for a variety of reasons including off-design-point efficiency loss, increased attrition from varying loads, unreliable outputs, and overall system costs. Thermal energy storage systems can address all of these issues by smoothing the thermal input to a constant and reliable level and providing back-up capacity for times when the thermal input is deactivated. Multiple types of thermal energy storage have been explored including sensible, latent, and thermochemical. Latent heat storage involves storing thermal energy in the reversible phase change of a phase change material, or PCM, and can have several advantages over other modalities including energy storage density, cost, simplicity, reliability, relatively constant temperature output, and temperature customizability. The largest obstacles to using latent heat storage include heat transfer rates, thermal cycling stability, and potentially corrosive PCMs. Targeting 86°C, the operating temperature of SDSU's experimental ORC, multiple potential materials were explored and tested as potential PCMs including Magnesium Chloride Hexahydrate (MgCl2˙6H2O), Magnesium Nitrate Hexahydrate (Mg(NO3)2˙6H 2O), montan wax, and carnauba wax. The

  10. A Burst Mode, Ultrahigh Temperature UF4 Vapor Core Reactor Rankine Cycle Space Power System Concept

    Science.gov (United States)

    Dugan, E. T.; Kahook, S. D.; Diaz, N. J.

    1996-01-01

    Static and dynamic neutronic analyses have been performed on an innovative burst mode (100's of MW output for a few thousand seconds) Ulvahigh Temperature Vapor Core Reactor (UTVR) space nuclear power system. The NVTR employs multiple, neutronically-coupled fissioning cores and operates on a direct, closed Rankine cycle using a disk Magnetohydrodynamic (MHD) generater for energy conversion. The UTVR includes two types of fissioning core regions: (1) the central Ultrahigh Temperature Vapor Core (UTVC) which contains a vapor mixture of highly enriched UF4 fuel and a metal fluoride working fluid and (2) the UF4 boiler column cores located in the BeO moderator/reflector region. The gaseous nature of the fuel the fact that the fuel is circulating, the multiple coupled fissioning cores, and the use of a two phase fissioning fuel lead to unique static and dynamic neutronic characteristics. Static neutronic analysis was conducted using two-dimensional S sub n, transport theory calculations and three-dimensional Monte Carlo transport theory calculations. Circulating-fuel, coupled-core point reactor kinetics equations were used for analyzing the dynamic behavior of the UTVR. In addition to including reactivity feedback phenomena associated with the individual fissioning cores, the effects of core-to-core neutronic and mass flow coupling between the UTVC and the surrounding boiler cores were also included in the dynamic model The dynamic analysis of the UTVR reveals the existence of some very effectlve inherent reactivity feedback effects that are capable of quickly stabilizing this system, within a few seconds, even when large positive reactivity insertions are imposed. If the UTVC vapor fuel density feedback is suppressed, the UTVR is still inherently stable because of the boiler core liquid-fuel volume feedback; in contrast, suppression of the vapor fuel density feedback in 'conventional" gas core cavity reactors causes them to become inherently unstable. Due to the

  11. The dish-Rankine SCSTPE program (Engineering Experiment no. 1). [systems engineering and economic analysis for a small community solar thermal electric system

    Science.gov (United States)

    Pons, R. L.; Grigsby, C. E.

    1980-01-01

    Activities planned for phase 2 Of the Small Community Solar Thermal Power Experiment (PFDR) program are summarized with emphasis on a dish-Rankine point focusing distributed receiver solar thermal electric system. Major design efforts include: (1) development of an advanced concept indirect-heated receiver;(2) development of hardware and software for a totally unmanned power plant control system; (3) implementation of a hybrid digital simulator which will validate plant operation prior to field testing; and (4) the acquisition of an efficient organic Rankine cycle power conversion unit. Preliminary performance analyses indicate that a mass-produced dish-Rankine PFDR system is potentially capable of producing electricity at a levelized busbar energy cost of 60 to 70 mills per KWh and with a capital cost of about $1300 per KW.

  12. 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...... plate heat exchangers which allows for efficient heat transfer with a compact design. Accurate heat transfer correlations characterizing these devices are required from the design phase to the development of model-based control strategies. In this paper, the experimental heat transfer coefficient...

  13. Technology Development Program for an Advanced Potassium Rankine Power Conversion System Compatible with Several Space Reactor Designs

    Energy Technology Data Exchange (ETDEWEB)

    Yoder, G.L.

    2005-10-03

    This report documents the work performed during the first phase of the National Aeronautics and Space Administration (NASA), National Research Announcement (NRA) Technology Development Program for an Advanced Potassium Rankine Power Conversion System Compatible with Several Space Reactor Designs. The document includes an optimization of both 100-kW{sub e} and 250-kW{sub e} (at the propulsion unit) Rankine cycle power conversion systems. In order to perform the mass optimization of these systems, several parametric evaluations of different design options were investigated. These options included feed and reheat, vapor superheat levels entering the turbine, three different material types, and multiple heat rejection system designs. The overall masses of these Nb-1%Zr systems are approximately 3100 kg and 6300 kg for the 100- kW{sub e} and 250-kW{sub e} systems, respectively, each with two totally redundant power conversion units, including the mass of the single reactor and shield. Initial conceptual designs for each of the components were developed in order to estimate component masses. In addition, an overall system concept was presented that was designed to fit within the launch envelope of a heavy lift vehicle. A technology development plan is presented in the report that describes the major efforts that are required to reach a technology readiness level of 6. A 10-year development plan was proposed.

  14. A Co-Powered Biomass and Concentrated Solar Power Rankine Cycle Concept for Small Size Combined Heat and Power Generation

    Directory of Open Access Journals (Sweden)

    Eileen Tortora

    2013-03-01

    Full Text Available The present work investigates the matching of an advanced small scale Combined Heat and Power (CHP Rankine cycle plant with end-user thermal and electric load. The power plant consists of a concentrated solar power field co-powered by a biomass furnace to produce steam in a Rankine cycle, with a CHP configuration. A hotel was selected as the end user due to its high thermal to electric consumption ratio. The power plant design and its operation were modelled and investigated by adopting transient simulations with an hourly distribution. The study of the load matching of the proposed renewable power technology and the final user has been carried out by comparing two different load tracking scenarios, i.e., the thermal and the electric demands. As a result, the power output follows fairly well the given load curves, supplying, on a selected winter day, about 50 GJ/d of thermal energy and the 6 GJ/d of electric energy, with reduced energy dumps when matching the load.

  15. Tax Area Boundaries, Utility, sanitary, lake, technical college, and other miscellaneous districts with taxing authority in Washing County are all maintained as attributes of the parcel feature., Published in 2013, 1:2400 (1in=200ft) scale, Washington County Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Tax Area Boundaries dataset current as of 2013. Utility, sanitary, lake, technical college, and other miscellaneous districts with taxing authority in Washing County...

  16. Selection of cooling fluid for an organic Rankine cycle unit recovering heat on a container ship sailing in the Arctic region

    DEFF Research Database (Denmark)

    Suárez de la Fuente, Santiago; Larsen, Ulrik; Pierobon, Leonardo

    2017-01-01

    air as coolant. This paper explores the use of two different coolants, air and seawater, for an organic Rankine cycle (ORC) unit using the available waste heat in the scavenge air system of a container ship navigating in Arctic Circle. Using a two-step single objective optimisation process, detailed...

  17. 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

    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...

  18. Author Details

    African Journals Online (AJOL)

    Ogunsanwo, OY. Vol 10, No 2 (2010) - Articles Utilization trend of wood species utilized in furniture industry in selected cities in Nigeria Abstract PDF · Vol 11, No 1 (2011) - Articles Spatial and Temporal Price Variations of Sawn Wood Utilized for Furniture Making in Selected Cities in Nigeria Abstract PDF · Vol 11, No 2 ...

  19. Author Details

    African Journals Online (AJOL)

    Arowosoge, OGE. Vol 10, No 2 (2010) - Articles Utilization trend of wood species utilized in furniture industry in selected cities in Nigeria Abstract PDF · Vol 11, No 1 (2011) - Articles Spatial and Temporal Price Variations of Sawn Wood Utilized for Furniture Making in Selected Cities in Nigeria Abstract PDF. ISSN: 1595-7470.

  20. 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.

  1. 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...... recovery. Included in the solution domain are 109 fluids in sub and supercritical processes, and the process is adapted to the properties of the individual fluid. The efficiency losses caused by imposing process constraints are investigated to help propose a suitable process layout. Hydrocarbon dry type...

  2. Improving the efficiency of heat supply systems on the basis of plants operating on organic Rankine cycle

    Science.gov (United States)

    Solomin, I. N.; Daminov, A. Z.; Sadykov, R. A.

    2017-11-01

    Results of experimental and analytical studies of the plant main element – plant turbomachine (turbo-expander) operating on organic Rankine cycle were obtained for facilities of the heat supply systems of small-scale power generation. At simultaneous mathematical modeling and experimental studies it was found that the best working medium to be used in the turbomachines of these plants is Freon R245fa which has the most suitable calorimetric properties to be used in the cycle. The mathematical model of gas flow in the turbomachine was developed. The main engineering dependencies to calculate the optimal design parameters of the turbomachine were obtained. The engineering problems of providing the minimum axial size of the turbomachine impeller were solved and the main design elements were unified.

  3. Experimental study on Rankine cycle evaporator efficiency intended for exhaust waste heat recovery of a diesel engine

    Directory of Open Access Journals (Sweden)

    Milkov Nikolay

    2017-01-01

    Full Text Available The paper pressents an experimental study of Rankine cycle evaporator efficiency. Water was chosen as the working fluid in the system. The experimental test was conducted on a test bench equipped with a burner charged by compressed fresh air. Generated exhaust gases parameters were previously determined over the diesel engine operating range (28 engine operating points were studied. For each test point the working fluid parameters (flow rate and evaporating pressure were varied. Thus, the enthalpy flow through the heat exchanger was determined. Heat exchanger was designed as 23 helical tubes are inserted. On the basis of the results, it was found out that efficiency varies from 25 % to 51,9 %. The optimal working fluid pressure is 20 bar at most of the operating points while the optimum fluid mass flow rate varies from 2 g/s to 10 g/s.

  4. 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......-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......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...

  5. 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......-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......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...

  6. 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 limitedefficiency of such machines is the main drawback. A solutionto enhance the system performance, also in Combined Heat andPower (CHP) arrangement, is the implementation of OrganicRankine Cycle (ORC) systems at the bottom of the gas turbines.Moreover, the resulting GT-ORC combined cycle could befurther...... a 10MW offshorewind farm and three gas turbines rated for 16:5MW, eachone coupled with an 4:5MW ORC module. The ORC mainparameters are observed under different wind power fluctuations.Due to the non-programmable availability of wind and powerdemand, the part-load and dynamic characteristics...

  7. 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.

  8. Systematic Methods for Working Fluid Selection and the Design, Integration and Control of Organic Rankine Cycles—A Review

    Directory of Open Access Journals (Sweden)

    Patrick Linke

    2015-05-01

    Full Text Available Efficient power generation from low to medium grade heat is an important challenge to be addressed to ensure a sustainable energy future. Organic Rankine Cycles (ORCs constitute an important enabling technology and their research and development has emerged as a very active research field over the past decade. Particular focus areas include working fluid selection and cycle design to achieve efficient heat to power conversions for diverse hot fluid streams associated with geothermal, solar or waste heat sources. Recently, a number of approaches have been developed that address the systematic selection of efficient working fluids as well as the design, integration and control of ORCs. This paper presents a review of emerging approaches with a particular emphasis on computer-aided design methods.

  9. Application Guide for Waste Heat Recovery with Organic Rankine Cycle Equipment.

    Science.gov (United States)

    1983-01-15

    Cycle Development and Its Application to Solar Energy Utilization," Ishikawajima - Harima Heavy Industries Co., Ltd. (AFI), International Congress of...20 , LU z 600 FOR ESTIMATING S800 "PURPOSES ’. Uj100 C 40000 DATA FROM SPS INC. ~t DATA FROM AFI -, 6000 0 DATA FROM ISHIKAWAJIMA - HARIMA 3. Figure 3-6...literature search and industry survey. Engineering criteria for applying ORC tech- nology are established, and a set of nomograms to enable the rapid

  10. Author Details

    African Journals Online (AJOL)

    Aliyu, J. Vol 19, No 1 (2013) - Articles Utilization of Prosopis africana pulp for rabbit feeding: 1.Effects on growth and economic performance. Abstract · Vol 19, No 1 (2013) - Articles Utilization of Prosopis africana pulp for rabbit feeding: 2. Effects on nutrient digestibility, blood components and carcass characteristics. Abstract.

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    Kwari, ID. Vol 19, No 1 (2013) - Articles Utilization of Prosopis africana pulp for rabbit feeding: 1.Effects on growth and economic performance. Abstract · Vol 19, No 1 (2013) - Articles Utilization of Prosopis africana pulp for rabbit feeding: 2. Effects on nutrient digestibility, blood components and carcass characteristics

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    Abstract PDF · Vol 8, No 11 (2009) - Articles Characterization of hydrocarbon utilizing bacteria in tropical marine sediments. Abstract PDF · Vol 5, No 4 (2006) - Articles Microbial growth and substrate utilization kinetics. Abstract PDF · Vol 5, No 5 (2006) - Articles Enhancement of recovery of residual oil using a biosurfactant ...

  13. Pareto utility

    NARCIS (Netherlands)

    Ikefuji, M.; Laeven, R.J.A.; Magnus, J.R.; Muris, C.H.M.

    2013-01-01

    In searching for an appropriate utility function in the expected utility framework, we formulate four properties that we want the utility function to satisfy. We conduct a search for such a function, and we identify Pareto utility as a function satisfying all four desired properties. Pareto utility

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    Insight into the Utilization of Cloud and Mobile Computing in a service oriented world. Abstract PDF · Vol ... Technical Challenges Hindering Development of Robust Wireless Network Platforms to Support Emerging Applications. Abstract PDF.

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    , Nigeria - A tropical Coastal Location Abstract PDF · Vol 20, No 1 (2008) - Articles Global solar radiation distribution and utilization seasons at Ilorin, Nigeria Abstract PDF · Vol 20, No 2 (2008) - Articles Referenced solar-related astronomical ...

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    Ogunbanjo, OB. Vol 20, No 1 (2015) - Articles Forensic odontological observations in the victims of DANA air crash. Abstract PDF. ISSN: 1937-8688. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... for Researchers · for Journals · for Authors ...

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    Chimaobi, O. Vol 3, No 1 (2006) - Articles Progeria: A desequencer of nature. Abstract. ISSN: 0794-6961. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors · for Policy Makers · about Open ...

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    Prinsloo, S. Vol 10, No 2 (2004) - Articles Electroconvulsive therapy and its use in modern-day psychiatry. Abstract PDF. ISSN: 2078-6786. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors ...

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    Pretorius, P.J.. Vol 10, No 2 (2004) - Articles Electroconvulsive therapy and its use in modern-day psychiatry. Abstract PDF. ISSN: 2078-6786. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors ...

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    Adu, M R. Vol 5, No 1 (2006) - Articles The ill effect of outages on National Electric Power Authority (NEPA): Ilorin 132/33kv substation as a case study. Abstract. ISSN: 1596-292X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners ...

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    Aronu, ME. Vol 13, No 2 (2009) - Articles Radiological evalution of civilian gunshot injuries in Nauth, Nnewi Abstract. ISSN: 1119-0388. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... for Researchers · for Journals · for Authors · for Policy Makers ...

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    Flegar, SJ. Vol 14, No 4 (2011) - Articles The neural correlates of intimate partner violence in women. Abstract PDF. ISSN: 1994-8220. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors ...

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    Fabricius, Christo. Vol 32 (2016) - Articles Viewpoint Environmental Slogans: Memes with Diverging Interpretations Abstract PDF. ISSN: 2411-5959. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... for Researchers · for Journals · for Authors ...

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    like lesions in Tanzania Abstract PDF. ISSN: 0012-835X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... for Researchers · for Journals · for Authors · for Policy Makers ...

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    Macleod, MJ. Vol 27 (2011) - Articles Is Prior Statin Therapy Associated with Increased Hemorrhagic Stroke? Abstract. ISSN: 0303-691X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors ...

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    Bornman, CL. Vol 20, No 1 (2013) - Articles Organisational culture of the South African construction industry. Abstract PDF. ISSN: 1023-0564. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors ...

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    Author Details. Journal Home > Advanced Search > Author Details. Log in or Register to get access to ... Tree, Anthony J. Vol 86, No 1-2 (2015) - Articles The status of the Damara Tern in the Eastern Cape, South Africa § Abstract. ISSN: 0030-6525. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for ...

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    Kumar, Sunil. Vol 2, No 2 (2010) - Articles Surgicel as an Unusual Cause of Prolonged Drainage Abstract PDF. ISSN: 2006-8808. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors · for Policy ...

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    Ulkur, F. Vol 18, No 1 (2015) - Articles Interdisciplinary orthognathic treatment of high angle class III malocclusion. Abstract PDF. ISSN: 1119-3077. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... for Researchers · for Journals · for Authors · for Policy ...

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    Khedher, A. Vol 1, No 1 (2013) - Articles Association of sarcoidosis and myasthenia gravis: Case Report Abstract. ISSN: 2307-2482. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors ...

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    Reich, Adam. Vol 15, No 5 (2016) - Articles Ziziphus mauritiana leaf extract emulsion for skin rejuvenation. Abstract PDF. ISSN: 1596-9827. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors ...

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    Ikemelu, CRK. Vol 3, No 3 (2014) - Articles Data Mining for Cyber Security Abstract PDF. ISSN: 2227-5444. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... for Researchers · for Journals · for Authors · for Policy Makers · about Open Access · FAQ's ...

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    Csongrady, KJ. Vol 6 (1984) - Articles Rainfall intensity data for Addis Ababa Abstract PDF. ISSN: 0514-6216. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors · for Policy Makers · about ...

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    Bassey, K.J.. Vol 8, No 3 (2002) - Articles On building a OR-based decision model via coherent pluralism. Abstract. ISSN: 1118-0579. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... for Researchers · for Journals · for Authors · for Policy Makers ...

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    Mustapha, AM. Vol 21, No 3 (2013) - Articles Comparison of Transportation Algorithms Using Data from Katsina State Transport Authority, Katsina State, Nigeria Abstract PDF. ISSN: 0794-5698. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    Osaji, EE. Vol 11, No 2 (2007) - Articles Exploration of the Energy Efficiency of the Greater London Authority Building (GLA Building/City Hall) Abstract PDF. ISSN: 1119-8362. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms ...

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    Elkordufani, Y. Vol 12, No 4 (2009) - Articles The psychological impact of vitiligo in adult Sudanese patients. Abstract PDF. ISSN: 1994-8220. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors ...

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    Utulu, S. Vol 26 (2010) - Articles DNA Damage Induced in the Germ and Bone Marrow Cells of Mice by Caffeine Abstract. ISSN: 0303-691X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors ...

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    Ebiti, N.W. Vol 50, No 1 (2009) - Articles Anorexia nervosa in a Nigerian – a case report. Abstract. Nigerian Medical Journal. ISSN: AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... for Researchers · for Journals · for Authors · for Policy Makers · about ...

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    Embu, HY. Vol 4, No 1 (2010) - Articles Anesthesia for surgery for typhoid perforation in a rural African hospital. Abstract. ISSN: 0331-3131. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors ...

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    Oyeyipo, I.P.. ISSN: 2467-8252. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL · News. OTHER RESOURCES... for Researchers · for Journals · for Authors · for Policy Makers · about ...

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    Newton, K. Vol 5, No 3 (2007) - Articles The spectrum of pyogenic liver abscesses and the principles of therapy. Abstract. ISSN: 1812-1659. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors ...

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    Chaukimath, SP. Vol 5, No 6 (2015) - Articles Orgasm Induced Seizures: A Rare Phenomenon Abstract PDF. ISSN: 2141-9248. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... for Researchers · for Journals · for Authors · for Policy Makers · about ...

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    Mtshali, S. Vol 21, No 3:2 (2015) - Articles Football Injuries during a South African University Sport Tournament Abstract. ISSN: 1117-4315. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors ...

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    Streicher, H. Vol 32, No 1 (2010) - Articles Travel motives of participants in the Cape Argus Pick n Pay Cycle Tour Abstract. ISSN: 0379-9069. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors ...

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    Odejobi, O.A.. Vol 12, No 2 (2003) - Articles A Neuro-Linguistic Model for Speech Recognition in Tone Language Abstract. ISSN: 1019-1593. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... for Researchers · for Journals · for Authors · for Policy ...

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    Chopra, D. Vol 66 (2013) - Articles Terpyridyl Complexes as Antimalarial Agents Abstract PDF. ISSN: 0379-4350. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... for Researchers · for Journals · for Authors · for Policy Makers · about Open Access ...

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    Audu-Peter, JD. Vol 7, No 1 (2010) - Articles Granule properties of paracetamol made with Bombax ceiba gum. Abstract. ISSN: 0189-8442. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors ...

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    Bode-Thomas, F. Vol 3, No 1 (2016) - Articles Enuresis among primary school children in Jos, Plateau State Abstract. ISSN: 2354-4325. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors ...

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    Author Details. Journal Home > Advanced Search > Author Details. Log in or Register to get access to full text downloads. ... Simulation study of excitation functions for cyclotron production of 99mTc using TALYS code. Abstract. ISSN: 0855-2215. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for ...

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    Hudson, J. Vol 11, No 2 (2007) - Articles Exploration of the Energy Efficiency of the Greater London Authority Building (GLA Building/City Hall) Abstract PDF. ISSN: 1119-8362. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners ...

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    Kilenga, N. Vol 4, No 1 (2015) - Articles West Africa Ebola Virus Disease Epidemic: The Africa Experience Abstract. ISSN: 2276-6839. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors ...

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    Opayele, AV. Vol 16, No 1 (2016) - Articles Yellow fever vaccination in Nigeria: focus on Oyo State Abstract. ISSN: 1596-2407. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... for Researchers · for Journals · for Authors · for Policy Makers · about Open ...

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    Farouk, L. Vol 26 (2010) - Articles Evaluation des Activities Analgesique et Antipyretique de Punica granatum. Abstract. ISSN: 0303-691X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors ...

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    Meludu, O. Vol 16 (2010) - Articles Epiboron Neutron Activation Analysis with Nigeria Research Reactor - 1. Abstract. ISSN: 1116-4336. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors ...

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    Ouagued, A. Vol 17 (2005) - Articles Etude experimentale des capteurs solaires a air: le sechage de la figue. Abstract. ISSN: 1111-0902. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... for Researchers · for Journals · for Authors · for Policy Makers ...

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    Omar, J. Vol 37 (2011) - Articles A Prisoner's Right?: The legal case for rehabilitation. Abstract PDF. ISSN: 1991-3877. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers · for Journals · for Authors · for Policy Makers ...

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    Author Details. Journal Home > Advanced Search > Author Details. Log in or Register to get access to full text downloads. ... Okosun, Victor Abhiele. Vol 10, No 2 (2016) - Articles Pedagogical Insights into the Teaching of Public Administration in Tertiary Institutions in Nigeria Abstract PDF. ISSN: 2070-0083. AJOL African ...

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    Author Details. Journal Home > Advanced Search > Author Details. Log in or Register to get access to full text downloads. ... Davis, D. Vol 30, No 4 (2012) - Articles Teaching social justice: Reframing some common pedagogical assumptions. Abstract. ISSN: 0258-2236. AJOL African Journals Online. HOW TO USE AJOL.

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    Permala, R. Vol 2 (1998) - Articles Environmental Health Impact Assessment Of A “Black Spot Area” In Mauritius Abstract. ISSN: 1694-0342. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... for Researchers · for Journals · for Authors · for Policy ...

  7. Dataset of working conditions and thermo-economic performances for hybrid organic Rankine plants fed by solar and low-grade energy sources.

    Science.gov (United States)

    Scardigno, Domenico; Fanelli, Emanuele; Viggiano, Annarita; Braccio, Giacobbe; Magi, Vinicio

    2016-06-01

    This article provides the dataset of operating conditions of a hybrid organic Rankine plant generated by the optimization procedure employed in the research article "A genetic optimization of a hybrid organic Rankine plant for solar and low-grade energy sources" (Scardigno et al., 2015) [1]. The methodology used to obtain the data is described. The operating conditions are subdivided into two separate groups: feasible and unfeasible solutions. In both groups, the values of the design variables are given. Besides, the subset of feasible solutions is described in details, by providing the thermodynamic and economic performances, the temperatures at some characteristic sections of the thermodynamic cycle, the net power, the absorbed powers and the area of the heat exchange surfaces.

  8. 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......The optimal design of the evaporator is one of the key issues to improve the efficiency and economics of organic Rankine cycle units. The first step in studying the evaporator design is to understand the thermal-hydraulic performance of the working fluid in the evaporator of organic Rankine cycles......, respectively. The working conditions covered relatively high saturation temperatures (corresponding reduced pressures of 0.35-0.74), which are prevailing in organic Rankine cycles yet absent in the open literature. The experimental data were compared with existing correlations, and new correlations were...

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

    OpenAIRE

    Daniel Maraver; Sylvain Quoilin; Javier Royo

    2014-01-01

    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 deman...

  10. 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.

  11. Organic Rankine-cycle power systems working fluids study: Topical report No. 1: Fluorinol 85. [85 mole % trofluoroethanol in water

    Energy Technology Data Exchange (ETDEWEB)

    Jain, M.L.; Demirgian, J.C.; Cole, R.L.

    1986-09-01

    An investigation to experimentally determine the thermal stability limits and degradation rates of Fluorinol 85 as a function of maximum cycle temperatures was initiated in 1982. Following the design and construction of a dynamic test loop capable of simulating the thermodynamic conditions of possible prototypical organic Rankine-cycle (ORC) power systems, several test runs were completed. The Fluorinol 85 test loop was operated for about 3800 h, covering a temperature range of 525-600/sup 0/F. Both liquid and noncondensable vapor (gas) samples were drawn periodically and analyzed using capillary column gas chromatography, gas chromatography/mass spectrometry and mass spectrometry. Results indicate that Fluorinol 85 would not decompose significantly over an extended period of time, up to a maximum cycle temperature of 550/sup 0/F. However, 506-h data at 575/sup 0/F show initiation of significant degradation. The 770-h data at 600/sup 0/F, using a fresh charge of Fluorinol 85, indicate an annual degradation rate of more than 17.2%. The most significant degradation product observed is hydrofluoric acid, which could cause severe corrosion in an ORC system. Devices to remove the hydrofluoric acid and prevent extreme temperature excursions are necessary for any ORC system using Fluorinol 85 as a working fluid.

  12. 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.

  13. Analysis and optimization of three main organic Rankine cycle configurations using a set of working fluids with different thermodynamic behaviors

    Science.gov (United States)

    Hamdi, Basma; Mabrouk, Mohamed Tahar; Kairouani, Lakdar; Kheiri, Abdelhamid

    2017-06-01

    Different configurations of organic Rankine cycle (ORC) systems are potential thermodynamic concepts for power generation from low grade heat. The aim of this work is to investigate and optimize the performances of the three main ORC systems configurations: basic ORC, ORC with internal heat exchange (IHE) and regenerative ORC. The evaluation for those configurations was performed using seven working fluids with typical different thermodynamic behaviours (R245fa, R601a, R600a, R227ea, R134a, R1234ze and R1234yf). The optimization has been performed using a genetic algorithm under a comprehensive set of operative parameters such as the fluid evaporating temperature, the fraction of flow rate or the pressure at the steam extracting point in the turbine. Results show that there is no general best ORC configuration for all those fluids. However, there is a suitable configuration for each fluid. Contribution to the topical issue "Materials for Energy harvesting, conversion and storage II (ICOME 2016)", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

  14. 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.

  15. About the prediction of Organic Rankine Cycles performances integrating local high-fidelity turbines simulation and uncertainties

    Science.gov (United States)

    Congedo, Pietro; de Santis, Dante; Geraci, Gianluca

    2014-11-01

    Organic Rankine Cycles (ORCs) are of key-importance when exploiting energy systems with a high efficiency. The variability of renewable heat sources makes more complex the global performance prediction of a cycle. The thermodynamic properties of the complex fluids used in the process are another source of uncertainty. The need for a predictive and robust simulation tool of ORCs remains strong. A high-order accurate Residual Distribution scheme has been recently developed for efficiently computing a turbine stage on unstructured grids, including advanced equations of state in order to take into account the complex fluids used in ORCs. Advantages in using high-order methods have been highlighted, in terms of number of degrees of freedom and computational time used, for computing the numerical solution with a greater accuracy compared to lower-order methods, even for shocked flows. The objective of this work is to quantify the numerical error with respect to the various sources of uncertainty of the ORC turbine, thus providing a very high-fidelity prediction in the coupled physical/stochastic space.

  16. 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.

  17. 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.

  18. Optimal design of solid oxide fuel cell, ammonia-water single effect absorption cycle and Rankine steam cycle hybrid system

    Science.gov (United States)

    Mehrpooya, Mehdi; Dehghani, Hossein; Ali Moosavian, S. M.

    2016-02-01

    A combined system containing solid oxide fuel cell-gas turbine power plant, Rankine steam cycle and ammonia-water absorption refrigeration system is introduced and analyzed. In this process, power, heat and cooling are produced. Energy and exergy analyses along with the economic factors are used to distinguish optimum operating point of the system. The developed electrochemical model of the fuel cell is validated with experimental results. Thermodynamic package and main parameters of the absorption refrigeration system are validated. The power output of the system is 500 kW. An optimization problem is defined in order to finding the optimal operating point. Decision variables are current density, temperature of the exhaust gases from the boiler, steam turbine pressure (high and medium), generator temperature and consumed cooling water. Results indicate that electrical efficiency of the combined system is 62.4% (LHV). Produced refrigeration (at -10 °C) and heat recovery are 101 kW and 22.1 kW respectively. Investment cost for the combined system (without absorption cycle) is about 2917 kW-1.

  19. 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.

  20. 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.

  1. Test Requirements and Conceptual Design for a Potassium Test Loop to Support an Advanced Potassium Rankine Cycle Power Conversion Systems

    Energy Technology Data Exchange (ETDEWEB)

    Yoder, JR.G.L.

    2006-03-08

    Parameters for continuing the design and specification of an experimental potassium test loop are identified in this report. Design and construction of a potassium test loop is part of the Phase II effort of the project ''Technology Development Program for an Advanced Potassium Rankine Power Conversion System''. This program is supported by the National Aeronautics and Space Administration. Design features for the potassium test loop and its instrumentation system, specific test articles, and engineered barriers for ensuring worker safety and protection of the environment are described along with safety and environmental protection requirements to be used during the design process. Information presented in the first portion of this report formed the basis to initiate the design phase of the program; however, the report is a living document that can be changed as necessary during the design process, reflecting modifications as additional design details are developed. Some portions of the report have parameters identified as ''to be determined'' (TBD), reflecting the early stage of the overall process. In cases where specific design values are presently unknown, the report attempts to document the quantities that remain to be defined in order to complete the design of the potassium test loop and supporting equipment.

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    methylisorboneol (2-MIB) in water from Zuikerbosch Treatment Plant (Rand Water) using â-cyclodextrin polyurethanes. Abstract PDF. ISSN: 0378-4738. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

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    carnitine optimal combinations in MPP+- induced cellular model of Parkinson's disease. Abstract PDF. ISSN: 0795-8080. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    carnitine supplementation on growth performance, carcass traits and blood parameters of broiler chickens. Abstract PDF. ISSN: 2221-4062. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's ...

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    Specific Health-Related Quality of Life Among Nigerians with Parkinson's Disease Abstract PDF. ISSN: 1597-4292. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    0362. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL · News. OTHER RESOURCES.

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    adipogenic effects of slendesta, standard potato extracts containing 5% protease inhibitor II Abstract PDF. ISSN: 0189-6016. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    microfibrous membranes with osteogenic induction of rBMSC for tissue engineering. Abstract PDF. ISSN: 1596-9827. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    -microfibrous membranes with osteogenic induction of rBMSC for tissue engineering. Abstract PDF. ISSN: 1596-9827. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES.

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    Assisted Extraction of Steroidal Saponins from Dioscorea zingiberensis C. H. Wright Abstract PDF. ISSN: 1596-9827. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    communication-style and parental neglect as predictors of aggressive tendencies among Secondary School adolescents. Abstract. ISSN: 0189-0263. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

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    Annelida: Oligochaeta) of forests in Limpopo Province, South Africa: diversity, communities and conservation. Abstract. ISSN: 2224-073X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's ...

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    Annonaceae) as a botanical insecticide against Callosobruchus maculatus Fabricius (Coleoptera:Bruchidae) Abstract. ISSN: 1597-0906. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's ...

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    HUSK ASH-CARBIDE-WASTE STABILIZATION OF RECLAIMED ASPHALT PAVEMENT Abstract PDF. ISSN: 2467-8821. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about ...

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    philosophical revolution' - a critique of Althusser's distinction between Scientific and Philosophic knowledge. Abstract. ISSN: 1118-1931. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More ...

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    .)Schott) in Ghana and suppression of symptom development with thiophanate methyl. Abstract PDF. ISSN: 2072-6589. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about ...

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    Uromyces viciae-fabae) with Environmental Factors and Cultural Practices in the Hararghe Highlands, Eastern Ethiopia Abstract. ISSN: 1992-0407. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

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    : presentation of U R L (unified modeling language) Abstract. ISSN: 1111-0015. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... Journal Quality · for Researchers ...

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    CLT) in Botswana: Perceptions of Implementation by some Teachers in Botswana's Junior Secondary Schools Abstract. ISSN: 0259-9570. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's ...

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    indigenous warthog population, Phacochoerus africanus, in the Free State Province, South Africa Abstract. ISSN: 2224-073X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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  9. Author Affiliations

    Indian Academy of Sciences (India)

    Author Affiliations. Vidyanand Nanjundiah1 Stuart A Newman2. Developmental Biology and Genetics Laboratory, Indian Institute of Science, Bangalore 560 012, India; Department of Cell Biology and Anatomy, Basic Sciences Building, New York Medical College, Valhalla, New York 10595, USA ...

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    sadh/034/01/0001-0002. Author Affiliations. Raja Natarajan1. School of Technology and Computer Science, Tata Institute of Fundamental Research, Mumbai 400 005. Sadhana. Current Issue : Vol. 43, Issue 1 · Current Issue Volume 43 | Issue ...

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    Psophocarpus tetragonolobus (L.) DC) for nodulation and phenotypic performance. Details. ISSN: 0855-1448. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    -Angiotensin Aldosterone System on Proteinuria in Patients with Diabetic Nephropathy and Advanced Azotemia Abstract PDF. ISSN: 1596-9827. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

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    Elaeagnaceae) Dry Fruit on the Activities of Hepatic Alcohol Dehydrogenase and Aldehyde Dehydrogenase in Mice Abstract PDF. ISSN: 1596-9827. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

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    Saccharomyces cerevisiae) on the growth and body composition of Heterobranchus longifilis fingerlings. Abstract. ISSN: 1596-972X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More ...

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    Journal Home > Advanced Search > Author Details. Log in or Register to get ... Vol 3, No 1 (2012) - Articles Graphic Design and the Changing Nature of Communication Media: A Historical Perspective and Implications for Design Training

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    Theropithecus gelada) living in and around the Simien Mountains National Park, Ethiopia Abstract PDF. ISSN: 0379-2897. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    catchment rainwater harvesting in western pare lowlands and Morogoro, Tanzania Abstract PDF. ISSN: 0856 668X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

  18. Author Affiliations

    Indian Academy of Sciences (India)

    Author Affiliations. C Bhattacharya1 J Saketha Nath2. Department of Computer Science and Automation, Indian Institute of Science, Bangalore 560012, India; Department of Computer Science and Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India ...

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    Journal Home > Advanced Search > Author Details. Log in or Register to get access to ... Bayoumi, R A. Vol 17 (2007) - Articles Isolation, purification, characterization, and physiological behavior of drinking water-borne pathogenic bacteria.

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    promoting compounds produced by Lyngbya majuscula in marine turtle fibropapillomatosis. Abstract. ISSN: 1814-232X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about ...

  1. Author Details

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    Bitter kola) in southwest Nigeria: opportunity for development of a biological product. Abstract PDF. ISSN: 1110-6859. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

  2. Derivation and Validation of a Novel Prognostic Scale (Modified-Stroke Subtype, Oxfordshire Community Stroke Project Classification, Age, and Prestroke Modified Rankin) to Predict Early Mortality in Acute Stroke.

    Science.gov (United States)

    Abdul-Rahim, Azmil H; Quinn, Terence J; Alder, Sarah; Clark, Allan B; Musgrave, Stanley D; Langhorne, Peter; Potter, John F; Myint, Phyo Kyaw

    2016-01-01

    The stroke subtype, Oxfordshire Community Stroke Project classification, age, and prestroke modified Rankin (SOAR) score is a prognostic scale proposed for early mortality prediction after acute stroke. We aimed to evaluate whether including a measure of initial stroke severity (National Institutes of Health Stroke Scale and modified-SOAR [mSOAR] scores) would improve the prognostic accuracy. Using Anglia Stroke and Heart Clinical Network data, 2008 to 2011, we assessed the performance of SOAR and mSOAR against in-hospital mortality using area under the receiver operating curve statistics. We externally validated the prognostic utility of SOAR and mSOAR using an independent cohort data set from Glasgow. We described calibration using Hosmer-Lemeshow goodness-of-fit test. A total of 1002 patients were included in the derivation cohort, and 105 (10.5%) died as inpatients. The area under the receiver operating curves for outcome of early mortality derived from the SOAR and mSOAR scores were 0.79 (95% confidence interval, 0.75-0.84) and 0.83 (95% confidence interval, 0.79-0.86), respectively (P=0.001). The external validation data set contained 1012 patients with stroke; of which, 121 (12.0%) patients died within 90 days. The mSOAR scores identified the risk of early mortality ranging from 3% to 42%. External validation of mSOAR score yielded an area under the receiver operating curve of 0.84 (95% confidence interval, 0.82-0.88) for outcome of early mortality. Calibration was good (P=0.70 for the Hosmer-Lemeshow test). Adding National Institutes of Health Stroke Scale data to create a modified-SOAR score improved prognostic utility in both derivation and validation data sets. The mSOAR may have clinical utility by using easily available data to predict mortality. © 2015 American Heart Association, Inc.

  3. 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.

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    Aghahowa, SE. Vol 16, No 1-3 (2015) - Articles Therapeutic Drug Mornitoring: Perception among Health-care Workers in a Developing Tertiary Institution Abstract · Vol 18, No 1-6 (2016) - Articles Vaccine Pharmacovigilance: Adverse Effects Reported and the Pattern of Vaccines Utilization in a Tertiary Institution, Nigeria.

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    Perrin, Michael R. Vol 41, No 2 (2006) - Articles Influence of density on the seasonal utilization of broad grassland types by white rhinoceroses. Abstract · Vol 44, No 2 (2009) - Articles Flocking dynamics and roosting behaviour of Meyer's parrot (Poicephalus meyeri) in the Okavango Delta, Botswana Abstract · Vol 39, No 2 ...

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    Osinaike, BB. Vol 18, No 2 (2012) - Articles ICU Utilization by Cardio-Thoracic Patients in a Nigerian Teaching Hospital: Any Role for HDU? Abstract PDF · Vol 21, No 1 (2015) - Articles Intra‑Operative Airway Management in Patients with Maxillofacial Trauma having Reduction and Immobilization of Facial Fractures

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    Yahaya, MK. Vol 9, No 1 (2011) - Articles Effect of Information Technology Communication (ICT) on women farmers' utilization of soya bean in conflict prone areas of Taraba State Nigeria Abstract · Vol 9, No 1 (2011) - Articles Radio listening habits of pupils of Nomadic Pastoralists and Migrant Fisherfolks in Nigeria Abstract.

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    ... Vol 9 (1992) - Articles Design and Realization of a Multi-EPROM Programmer Abstract PDF · Vol 16 (1999) - Articles Coding and transmission of non uniform alphabets. Abstract PDF · Vol 18 (2001) - Articles An Adaptive Coding Scheme For Effective Bandwidth And Power Utilization Over Noisy Communication Channels

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    Aliyu, Murtala. Vol 6, No 1 (2015) - Articles Utilization of reference resources and services by users of Benue State public library, Makurdi, Nigeria Abstract PDF · Vol 6, No 2 (2015) - Articles Improving Library and Information Services: use of appropriate Information Communication Technology in Nigerian libraries

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    Feed intake, growth and feed utilization patterns of pigs highly divergent in growth rate. Abstract PDF · Vol 18, No 2 (1988) - Articles Class FH sunflower seeds (Helianthus annuus) as an energy/protein source for early weaned piglets. Abstract PDF · Vol 18, No 2 (1988) - Articles The in vivo prediction of body composition in ...

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    Gawu, SKY. Vol 29, No 2 (2009) - Articles Geochemical And Mineralogical Characteristics Of Lithomargic Clay Types From Awaso Bauxite Deposit, Ghana: Implications For Possible Industrial Utilization Abstract PDF. ISSN: 0855-0395. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians ...

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    A Case report: Herpes zooster IRIS in pregnancy ... admissions in a large urban hospital in Uganda: prevalence, clinical and laboratory features and implications for planning patient management ... The Utility of the helicobacter pylori stool antigen test in managing dyspepsia: an experience from a low resource setting

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    Abaidoo, R.C.. Vol 3, No 1 (2001): - Articles Soil nitrogen availability and Bradyrhizobium spp. inoculation influence the utilization of nitrogen resources in legume-cereal systems. Details · Vol 3, No 2 (2001): - Articles Nodulation and nitrogen uptake characteristics as selection indices for promiscuous soybean breeding in ...

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    Utilization of Dalbergia melanoxylon (guill. & perr.) in Tanzania: a case study of Nachingwea district. Abstract · Vol 75, No 1 (2004) - Articles Determination of basic density and strength properties of Cordia africana lam. grown in agroforestry system in Lushoto, Tanga Abstract · Vol 76, No 1 (2007) - Articles Basic Density And ...

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    Response of growing rabbits to graded levels of fermented and unfermented pineapple peel. Abstract · Vol 38, No 2 (2011) - Articles Utilization of hatchery waste meal in cassava products based broiler finisher diets. Abstract · Vol 39, No 2 (2012) - Articles Effects of raw and toasted Daniellia oliveri (Rolfe) seed meal on ...

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    Factors affecting utilization of long lasting insecticide treated nets. Abstract PDF · Vol 2, No 4 (2014) - Original Article Integrated disesase surveillance and response reporting: effects of training on primary healthcare workers in plateau state, Nigeria Abstract PDF. ISSN: 2467-8252. AJOL African Journals Online. HOW TO ...

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    Ofori-Sarpong, G. Vol 9 (2007) - Articles Utilization of Microwave Energy in the Calcination and Agglomeration of Nsuta Manganese Carbonate Ore Abstract · Vol 12 (2011) - Articles Recycling Potential of Waste Di-Isobutyl-Ketone (DIBK) and Recovery of Residual Gold Abstract PDF · Vol 14 (2013) - Articles

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    Renuka, IV. Vol 6, No 3 (2016) - Articles Utility of Bacillary Index in Slit Skin Smears in Correlation with Clinical and Histopathological Alterations in Hansen's Disease: An Attempt to Revive a Simple Useful Procedure Abstract PDF. ISSN: 2141-9248. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for ...

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    Osuh, ME. Vol 11, No 1 (2013) - Articles Effectiveness of an Oral Health Care Training Workshop for School Teachers: A Pilot Study Abstract PDF · Vol 12, No 1 (2014) - Articles Dental Services and Attitudes towards its regular Utilization among Civil Servants in Ibadan, Nigeria Abstract PDF. ISSN: 1597-1627. AJOL African ...

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    Patterns of prescribing and utilization of asthma medications in a tertiary hospital in Dubai, United Arab Emirates Abstract PDF · Vol 15, No 10 (2016) - Articles Bioactive content, hepatoprotective and antioxidant activities of whole plant extract of Micromeria fruticosa (L) Druce ssp Serpyllifolia F Lamiaceae against Carbon ...

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    Knowledge, Attitude and Self-management Practices of Patients with Type 2 Diabetes in an Ambulatory Care Setting in Ibadan, Nigeria Abstract · Vol 29, No 2 (2011) - Articles Utilization and Incidence of Adverse Drug Reactions to Artemisinin-Based Combination Therapy Among Pregnant Women in an Ambulatory Care ...

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    Okonkwo, I.J.. Vol 19, No 1 (2017) - Articles Effect of dietary supplementation of guinea hen weed (Petiveria alliacea) leaf and root meals on nutrient utilization and intestinal morphology of finishing broiler chicken. Abstract. ISSN: 1119-4308. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for ...

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    Abebrese, IK. Vol 19 (2006) - Articles A post-logging assessment of some soil physical properties in a Ghanaian moist semi-deciduous forest. Abstract · Vol 20, No 1 (2007): Volumes 20 & 21 - Articles Indigenous Fruits Utilization In Semi-Arid Zones: A Baseline Study In A Savannah Environment In Ghana Abstract.

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    The impact of advocacy and community mobilization on the utilization of health services at the Comprehensive Health Centre, Gindiri. Abstract PDF · Vol 19, No 2 (2010) - Articles Knowledge and Treatment Practices of Malaria among Mothers and Caregivers of Children in an Urban Slum in Jos, Nigeria Abstract · Vol 51, No ...

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    Chingle, MP. Vol 4, No 1 (2009) - Articles The impact of advocacy and community mobilization on the utilization of health services at the Comprehensive Health Centre, Gindiri. Abstract PDF · Vol 5, No 1 (2010) - Articles Indoor air pollution in rural settings in Plateau State, Nigeria Abstract PDF · Vol 6, No 1 (2012) - Articles

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    Adejumo, PO. Vol 11, No 2 (2012) - Articles Incorporationg genetics and genomics nursing into client care. Abstract PDF · Vol 12, No 1 (2013) - Articles Nurses' attitude to reading research articles and their perception of research utilization in clinical practice in a Nigerian city. Abstract PDF · Vol 13, No 1 (2014) - Articles

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    Diffuse Solar System Design and Utilization in Agriculture and Domestic Applications Abstract · Vol 9, No 2 (2011) - Articles Operational Principle of Water Level Detector for Agricultural and Domestic Use Abstract · Vol 11, No 2 (2013) - Articles Egg incubator control system with short message service (sms) fault analysis ...

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    Utilization of family planning services in a Nigerian tertiary hospital: a six year review. Abstract · Vol 31, No 2 (2014) - Articles Premature rupture of membranes at term: immediate induction of labor versus expectant management. Abstract · Vol 30, No 2 (2013) - Articles Awareness of cervical cancer and its prevention among ...

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    Where there is no anaesthetist: the role of obstetrician - administered spinal anaesthesia for emergency caesarean section. Abstract · Vol 31, No 2 (2014) - Articles Utilization of family planning services in a Nigerian tertiary hospital: a six year review. Abstract · Vol 31, No 2 (2014) - Articles Premature rupture of membranes at ...

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    Omada, JI. Vol 4, No 2 (2006) - Articles Field and compositional studies of sedimentary ironstone deposit in Udubo area, Northeastern, Nigeria Abstract · Vol 7, No 1 (2009) - Articles The geologic setting, physico-chemical characteristics and utilization scheme of spring water at Patti ridge, Lokoja, central Nigeria Abstract.

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    Makokha, JW. Vol 8 (2015): Supplement 2 - Articles Retrieval of Aerosol Optical Depth Over Ecologically Stressed East African Land Surfaces from Top of Atmosphere Radiance Utilizing the Aerosol Free Vegetation Index Abstract PDF. ISSN: 1998-0507. AJOL African Journals Online. HOW TO USE AJOL... for Researchers ...

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    Nutritive value of ripe and unripe(green) plantain peels (Musa paradisiaca) for broiler chicken. Abstract · Vol 2, No 1 (1999) - Articles Utilization of raw and autoclaved whole pods of Samenea Saman(Jaco Merill) by the domestic rabbit. Abstract · Vol 3, No 2 (2000) - Articles The performance of West African dwarf goat on ...

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    Electrical muscle stimulation (EMS) training of the hamstrings. Abstract · Vol 20, No 4-2 (2014) - Articles Analysis of physical activity and health profiles and the utilization of the Biokinetic Humanitarian Project among senior university students. Abstract · Vol 22, No 3:2 (2016) - Articles The effects of a visual intervention ...

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    Obi, JC. Vol 7, No 3 (2011) - Articles Intelligent neuro fuzzy expert system for autism recognition. Abstract · Vol 7, No 3 (2011) - Articles Chronic obstructive pulmonary disease prognostic diagnosis utilizing fuzzy classifier proficient approach. Abstract. ISSN: 0794-4713. AJOL African Journals Online. HOW TO USE AJOL.

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    Deveau, CS. Vol 7, No 2 (2008) - Articles HIV prevention among drug and alcohol users: models of intervention in Kenya Abstract PDF · Vol 9, No 2 (2010) - Articles Utilization of community-based outpatient addiction treatment programmes in Kenya Abstract PDF. ISSN: 1531-4065. AJOL African Journals Online. HOW TO ...

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    Knowledge And Experience Of Work-Related Hazards And Utilization Of Safety Practices Among Solid Waste Scavengers In Ilorin Metropolis, Kwara State, Nigeria Abstract · Vol 25, No 1 (2018) - Articles Prevalence of work-related health problems among providers of car battery repair in a resource-limited setting. Abstract.

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    Utilization of graded levels of cowpea waste meal in broiler finisher ration. Abstract · Vol 4, No 2 (2001) - Articles Replacement value of Kolanut husk meal for maize in. Abstract · Vol 13 (2011) - Articles Performance, Nutrient Digestibility and Carcass Characteristics of Broilers Fed Cocoa Pod Husk-Based Diets Abstract.

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    Utility Interfaced Pulse-Width Modulation of Solar Fed Voltage Source Inverter Using Fixed-Band Hysteresis Current Controller Method Abstract PDF · Vol 34, No 1 (2015) - Computer, Telecommunications, Software, Electrical & Electronics Engineering Solar-Based Boost Differential Single Phase Inverter Abstract PDF.

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    Ogunlade, I. Vol 11, No 1 (2011) - Articles Youth Development Agents' Needs: Challenges for Extension Volunteer Management Competencies in Nigeria Abstract PDF · Vol 6, No 1-2 (2004) - Articles Information sources used and constraints in adoption of soya bean production and utilization technologies in Kwara state ...

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    Studies on animal traction in Northwestern Nigeria I. Characterisation and management of animals used for draught ... Haematological and Biochemical Indices of Growing Lambs Fed Fore-Stomach Digesta and Poultry Litter Waste ... Utilization of Senna obtusifolia as a Potential Non-Conventional Feedstuff In Sheep

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    The novel use of “point of care” devices to evaluate transport duration on selected pork quality parameters. Abstract PDF · Vol 23, No 5 (1993) - Articles Utilization of metabolizable energy by ostrich (Struthio camelus) chicks at two different concentrations of dietary energy and crude fibre originating from lucerne1

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    Mabawonku, Iyabo. Vol 34, No 2 (2000) - Articles Personal Effectiveness Attribute of legal Practitioners As Correlates of Information Utilization in Laos, Nigeria Abstract · Vol 48, No 1-2 (2015) - Articles Citation analysis of doctoral theses submitted to the department of library, archival and information studies, university of ...

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    An appraisal of digital reference services in Nigerian university libraries. Abstract · Vol 9, No 2 (2012) - Articles Information resources and access in Delta State University library, Abraka-Nigeria Abstract · Vol 10, No 1 (2013) - Articles Utilization of academic library by lecturers and students for research productivity: A survey ...

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    Iwara, FU. Vol 9, No 1 (2012) - Articles Utilization of HIV/AIDS Information among Women in Calabar South Local Government Area of Cross River State, Nigeria Abstract · Vol 11, No 2 (2014) - Articles An assessment of the collection development and acquisition processes in Kenneth Dike library, University of Ibadan, ...

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    Tegegn, A. Vol 19, No 2 (2009) - Articles Adolescent reproductive health services in Jimma City: Accessibility and utilization. Abstract PDF · 2012: Special Issue - Articles Risk Factors for Chronic Non-Communicable Diseases at Gilgel Gibe Field Research Center, Southwest Ethiopia: Population Based Study Abstract PDF.

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    Gender relations in utilization and conservation of the Kilombero flood plains Ramsar site wetlands, Tanzania Abstract · Vol 81, No 2 (2012): Special Issue - Articles Influence of hydrological fluctuations on vegetation and Avifauna species composition, abundance and diversity in the Bahi Swamp wetlands Central Tanzania

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    An Overview of Africa's Marine Resources: Their Utilization and Sustainable Management Details · Vol 12, No 3 (2000) - Articles EDITORIAL Ganoderma Lucidum - Paramount among Medicinal Mushrooms. Details · Vol 15, No 3 (2003) - Articles Editorial: Africa's Mushrooms: A neglected bioresource whose time has come

  8. Vision 2021. The utilities future

    Energy Technology Data Exchange (ETDEWEB)

    Liere, J. van [KEMA, Arnhem (Netherlands)

    1996-12-01

    The electricity industry is gradually making the transition to a free market economy characterized by competition. With the arrival of a more market-oriented structure, the electricity companies have taken measures to reduce costs while retaining reliability and safety of the production and distribution. Today the majority of these efforts are oriented towards optimizing the scope and the structure of the organizations and towards streamlining internal processes in order to improve productivity. Throughout the world, the increasing competition among utilities is accompanied by the unbundling of production, transport, distribution and customer service functions. There is a remarkable similarity between the transitions in the computer industry some years ago (from main frame to personal PC`s) and in the electric utility industry today. The new structure is expected to be less centralized and more dispersed. In the dispersed generation concept the locally deployed power plant must become smaller, more flexible, more efficient and less expensive than today`s power plants. Power generation is gradually changing from a steam cycle (Rankine cycle) via the combined cycle to the gas cycle (Brayton cycle). The fuel used to power the gas turbine is expected to change in the future from high calorific to low calorific gas, generated from biomass, waste, oil residues, blast furnaces, coal, etc. Five new areas to be addressed have been identified that can be characterized as follows: (a) improved utilization of capital-intensive production resources to reduce costs, (b) electrification and the supply of heat to increase sales and market share, (c) sustainable developments to broaden our future resource base, (d) improved efficiency based on the Brayton cycle to increase flexibility, (e) development of energy services with new secondary services to stay in the market. (EG) 10 refs.

  9. Utility Energy Services Contracts: Enabling Documents

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-05-01

    Utility Energy Services Contracts: Enabling Documents provides materials that clarify the authority for Federal agencies to enter into utility energy services contracts (UESCs), as well as sample documents and resources to ease utility partnership contracting.

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

    Energy Technology Data Exchange (ETDEWEB)

    Guillen, Donna Post [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zia, Jalal [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    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

  11. 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.

  12. Prediction of two month modified Rankin Scale with an ordinal prediction model in patients with aneurysmal subarachnoid haemorrhage

    Directory of Open Access Journals (Sweden)

    Sneade Mary

    2010-09-01

    Full Text Available Abstract Background Aneurysmal subarachnoid haemorrhage (aSAH is a devastating event with a frequently disabling outcome. Our aim was to develop a prognostic model to predict an ordinal clinical outcome at two months in patients with aSAH. Methods We studied patients enrolled in the International Subarachnoid Aneurysm Trial (ISAT, a randomized multicentre trial to compare coiling and clipping in aSAH patients. Several models were explored to estimate a patient's outcome according to the modified Rankin Scale (mRS at two months after aSAH. Our final model was validated internally with bootstrapping techniques. Results The study population comprised of 2,128 patients of whom 159 patients died within 2 months (8%. Multivariable proportional odds analysis identified World Federation of Neurosurgical Societies (WFNS grade as the most important predictor, followed by age, sex, lumen size of the aneurysm, Fisher grade, vasospasm on angiography, and treatment modality. The model discriminated moderately between those with poor and good mRS scores (c statistic = 0.65, with minor optimism according to bootstrap re-sampling (optimism corrected c statistic = 0.64. Conclusion We presented a calibrated and internally validated ordinal prognostic model to predict two month mRS in aSAH patients who survived the early stage up till a treatment decision. Although generalizability of the model is limited due to the selected population in which it was developed, this model could eventually be used to support clinical decision making after external validation. Trial Registration International Standard Randomised Controlled Trial, Number ISRCTN49866681

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    R M, Lynch. Vol 11, No 1 (2016) - Articles Bilateral Re-Expansion Pulmonary Oedema– When the Cure Is Worse Than the Disease Abstract. ISSN: 1858-5051. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and ...

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    Lynch, K. Vol 2 (2009) - Articles A Model for Scaffolding Traditional Distance Learners in Africa for Constructivic Online Learning Abstract. ISSN: 1816-6822. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions ...

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    Lynch, RM. Vol 9, No 3 (2014) - Articles ECG lead misplacement by colour – What difference does it make? Abstract. ISSN: 1858-5051. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL ...

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    The-Shelf Canned Food Products Using PCR-Based Molecular Technique Abstract. ISSN: 0189-7241. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ...

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    Fafiolu, A O. Vol 43, No 1 (2016) - Articles Growth performance, haematology and serum biochemistry of weaned pigs fed Lcarnitine supplemented diets. Abstract. ISSN: 0331-2062. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners ...

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    Waris, A. Vol 91, No 2 (2014) - Articles Randomised Double Blind Study to Compare Effectiveness of Honey, Salbutamol and Placebo in Treatment of Cough in Children with Common Cold Abstract PDF. ISSN: 0012-835X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

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    Indian Academy of Sciences (India)

    Astr. (2010) 31, 221–222. Author Index. Aggarwal Malini see Jain Rajmal, 155. Aghaee, A. Determination of the Mean Hi Absorption of the Intergalactic. Medium, 59. Agrawal, S. P. see Singh Ambika, 89. Biesiada Marek Could the Optical Transient SCP 06F6 be due to Micro- lensing?, 213. C¸ aliskan, S . see Küçük, ˙I., 135.

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    Onwuchekwal, Arthur. Vol 14, No 2 (2014) - Articles Profile of Generic and Disease-Specific Health-Related Quality of Life Among Nigerians with Parkinson's Disease Abstract PDF. ISSN: 1597-4292. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

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    van Dyk, A. Vol 10, No 4 (2005) - Articles The contribution of the clinical nurse instructor to the development of critical thinking skills of the student. Abstract. ISSN: 2071-9736. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms ...

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    Shawa, LB. Vol 3, No 2 (2014) - Articles Blending critical thinking skills with the teaching of subject matter: Case of a geography lesson in a Malawi School Abstract PDF. ISSN: 2227-5444. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ...

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    Mokibelo, EB. Vol 5 (2008) - Articles The Impact of Hostel Conditions on Learning and Reading Ability of. Abstract. ISSN: 1813-2227. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL ...

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    Gururaj, TR. Vol 14, No 3 (2011) - Articles Probable autoimmune causal relationship between periodontitis and Hashimotos thyroidits: A systemic review. Abstract PDF. ISSN: 1119-3077. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES.

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    Elsherbiny, TM. Vol 47, No 4 (2011) - Articles Hashimoto thyroiditis is an independent cardiovascular risk factor in clinically hypothyroid patients. Abstract PDF. ISSN: 2090-2948. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners ...

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    Tshishonga, Ndwakhulu. Vol 60 (2015) - Articles Book Review: Urban governance in post-apartheid cities. Modes of Engagement in South Africa's Metropoles Abstract. ISSN: 1607-2820. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ...

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    Mhlahlo, S R. Vol 23, No 1 (2007) - Articles Assessment of Urban Governance in Zimbabwe: Case of the City of Gweru Abstract. ISSN: 1684-4173. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use ...

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    Omotoso, AB. Vol 30, No 1 (2003) - Articles Cardiac Arrhythmias in Children with Sickle Cell Anaemia Abstract PDF. ISSN: 0302-4660. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL ...

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    Bello, O.A.. Vol 38, No 1 (2017) - Articles Prevalence of helminth parasites of domestic pigeons (Columba livia) in Jalingo Metropolis, Taraba State Abstract. ISSN: 1117-4145. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners ...

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    Gabaolu, C. Vol 33, No 1 (2012) - Articles Ecto and Gastrointestinal Parasites of Captured Wild Pigeons in Benin City, Nigeria Abstract. ISSN: 1117-4145. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of ...

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    Ademola, IO. Vol 53, No 2 (2005) - Articles Helminth parasites of domestic pigeons (Columbia livia) in Ibadan, Nigeria Abstract. ISSN: 0378-9721. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use ...

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    Siminialayi, IM. Vol 26 (2010) - Articles The Effect of Aloe vera Plus on the Liver: A Pharmacovigilance Study in Rats Abstract. ISSN: 0303-691X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use ...

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    Mayayise, G. Vol 11, No 1 (2012) - Articles A pharmacovigilance study of adults on highly active antiretroviral therapy, South Africa: 2007 – 2011. Abstract PDF. ISSN: 1937-8688. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners ...

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    Bekker, L-G. Vol 5, No 3 (2005) - Articles Socio-behaviour challenges to phase III HIV vaccine trials in Sub-Saharan Africa Abstract PDF. ISSN: 1680-6905. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of ...

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