• Title/Summary/Keyword: ORC

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Study on the Thermal Characteristics of Organic Rankine Cycles for Use of Low-Temperature Heat Source (저온열원 활용을 위한 유기랭킨사이클의 열적 특성에 관한 연구)

  • Jin, Jae-Young;Kim, Kyoung-Hoon
    • 한국태양에너지학회:학술대회논문집
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    • 2011.04a
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    • pp.191-194
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    • 2011
  • Low-grade waste heat has generally been discarded in industry due to lack of efficient recovery methods. In recent years, organic Rankine cycle(ORC) has become a field of intense research and appears as a promising technology for conversion of heat into useful work of electricity. In this work thermodynamic performance of ORC with superheating of vapor is comparatively assessed for various working fluids. Special attention is paid to the effects of system parameters such as the evaporating temperature on the characteristics of the system such as maximum possible work extraction from the given source, volumetric flow rate per 1 kW of net work and quality of the working fluid at turbine exit as well as thermal efficiency.

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A Study on Effect of Flow Characteristics for Turbine Impeller Shape (Turbine Impeller 형상이 유동특성에 미치는 영향에 관한 연구)

  • Jeon, Eon-Chan;Youn, Gi-Ho;Kang, Chang-Hun
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.4
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    • pp.36-43
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    • 2014
  • Recently, research has been conducted to develop the ORC (organic Rankine cycle), to recover waste heat from facilities such as industrial plants ultimately to create mechanical or electrical energy. The ORC system consists of a heat exchange, a condenser, a pump and a boiler. In this paper, 84 flow analyses were conducted with 21 cases and three variables, i.e., a number of large wings, a number of small wings, and RPMs. R245fa was used as a refrigerant. The flow cavitation phenomenon was investigated through a flow analysis, and a flow stream analysis was conducted.

Comparative Thermodynamic Analysis of Organic Rankine Cycle and Ammonia-Water Rankine Cycle (유기랭킨사이클과 암모니아-물 랭킨사이클의 열역학적 성능의 비교 해석)

  • KIM, KYOUNG HOON;KIM, MAN-HOE
    • Transactions of the Korean hydrogen and new energy society
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    • v.27 no.5
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    • pp.597-603
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    • 2016
  • In this paper a comparative thermodynamics analysis is carried out for organic Rankine cycle (ORC) and ammonia-water Rankine cycle (AWRC) utilizing low-grade heat sources. Effects of the working fluid, ammonia concentration, and turbine inlet pressure are systematically investigated on the system performance such as mass flow rate, pressure ratio, turbine-exit volume flow, and net power production as well as the thermal efficiency. Results show that ORC with a proper working fluid shows higher thermal efficiency than AWRC, however, AWRC shows lower mass flow rate of working fluid and lower pressure ratio of expander than ORC.

Speed Estimation Method of Turbine and Generator using Variable Frequency type PR controller and Positive-phase-sequence Component Computation in ORC Generation System (ORC 발전 시스템에서 주파수 가변형 PR 제어기와 정상분 추출을 이용한 발전기 속도추정 방법)

  • Park, Hyung-Seok;Heo, Hong-Jun;Kim, Jang-Mok
    • Proceedings of the KIPE Conference
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    • 2015.07a
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    • pp.377-378
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    • 2015
  • 본 논문에서는 유기랭킨 사이클(organic rankine cycle: ORC) 발전 시스템에서 터빈과 발전기의 속도를 추정하는 방법을 제안한다. 다이오드 정류기에 의해 왜곡된 발전기 3상 단자 전압은 PLL 기법을 이용한 속도추정의 성능을 저하시키므로, 정상분 추출과 맥동성분 제거를 위한 상태관측기와 주파수 가변형 PR 제어기를 동기좌표계 PLL 기법에 적용하여 발전기의 속도를 추정한다. 제안하는 터빈과 발전기의 속도추정 방법은 실험 결과를 통해 그 성능을 검증한다.

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The development of a preliminary designing program for ORC radial inflow turbines and the design of the radial inflow turbine for the OTEC (ORC 반경류터빈의 예비설계프로그램 개발 및 OTEC용 반경류터빈의 설계)

  • Kim, Do-Yeop;Kang, Ho-Keun;Kim, You-Taek
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.3
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    • pp.276-284
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    • 2014
  • The purpose of this study is to establish the designing method of ORC(Organic Rankine Cycle) radial inflow turbines. RTDM(Radial Turbine Design Modeler) Ver.2.1 which is a preliminary design program of radial inflow turbines was developed to achieve this purpose. The 200kW-class radial inflow turbine for OTEC(Ocean Thermal Energy Conversion) was designed by using the RTDM Ver.2.1 and CFD(Computational Fluid Dynamics) simulation was performed to verify the accuracy of RTDM Ver.2.1. With the result of simulation, the accuracy of RTDM Ver.2.1 was almost 94.6% based on the designed total enthalpy drop of the radial inflow turbine. Strategy of adjusting the mass flow rate was adopted on this study to satisfy the requirements of its power and rotor outlet's conditions for the designed radial inflow turbine. The mass flow rate was consequently increased to 21.2 kg/s for the designed 200kW-class radial inflow turbine for OTEC, and then Total to total and Total to static efficiency are 89.8% and 85.36% respectively.

Performance Characteristics of Organic Rankine Cycles Using Medium Temperature District Heating Water as Heat Source (지역난방용 중온수 열원 유기랭킨사이클 성능 특성)

  • Park, Woo-Jin;Yoo, Hoseon
    • Plant Journal
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    • v.12 no.1
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    • pp.29-36
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    • 2016
  • It is becoming increasingly important to make use of alternative energy source. because It is not able to rely on only fossil fuel for the recent increasing demand of energy consumption. With this situation, lots of studies for utilizing low grade energy such as industrial waste heat, solar energy, and geothermal energy have been conducted. The aim of this study is to predict the operation characteristics of working fluid by using performance analysis program (ThermoFlex) through the system analysis which is not mixing district return water but using ORC(Organic Rankine Cycle, hereinafter ORC) as a downstream cycle when accumulating district heating (hereinafter DH). In this study, We conducted the performance analysis for the case which has the district heating water temperature($120^{\circ}C$) and Flow rate of $163m^3/h$ (including District Heating return water flow), and examined several working fluid which is proper to this temperature. The case using R245fa (which is the best-case) showed 269.2kW power output, 6.37% efficiency. Additionally, Cut down on fuel was expected because of the boiler inlet temperature increase by being Formed $57.3{\sim}85^{\circ}C$ in a temperature of district heating return water, depending on a pressure change of a condenser in ORC system.

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A Study on the Thermal Flow of Waste Heat Recovery Unit (WHRU) for Ship's Organic Rankine Cycle Power Generation System using CFD Method (CFD를 활용한 선박고온도차발전용 WHRU의 열유동 해석에 관한 연구)

  • Whang, Dae-jung;Park, Sang-kyun;Jee, Jae-hoon;Bang, Eun-shin;Oh, Cheol
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.27 no.5
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    • pp.647-655
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    • 2021
  • The IMO (International Maritime Organization) is discussing the improvement of energy ef iciency of ships in order to reduce greenhouse gas emissions from ships. Currently, by applying an ORC power generation system using waste heat generated from ships, high energy conversion efficiency can be expected from ships. This technology uses an organic medium based on Freon or hydrocarbons as the working fluid, which evaporates at a lower temperature range than water. Through this, it is possible to generate steam (gas) and generate power at a low and low temperature relatively. In this study, the analysis of heat flow between the refrigerant and waste heat in the ORC power generation system, which is an organic Rankine cycle, is analyzed using 3D simulation techniques to determine the temperature change, velocity change, pressure change, and mass change of the fluid flowing of the WHRU (Waste Heat Recovery Unit) inside and the outside the structure. The purpose of this study is to analyze how the mass change affects the structure, and this study analyzed the heat transfer of the heat exchanger from the refrigerant and the exhaust gas of the ship's main engine in the ORC power generation system using this technique.

Fabrication and Study on the Performance Characteristics of a Scroll Expander for Organic Rankine Cycle (유기랭킨사이클용 소형 스크롤 팽창기 제작 및 성능 특성 연구)

  • Baek, Seungdong;Sung, Taehong;Lee, Minseok;Kim, Kyung Chun
    • Journal of the Korean Institute of Gas
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    • v.20 no.5
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    • pp.50-56
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    • 2016
  • In this work, the open-drive oil free air compressor is modified to activate an organic Rankine cycle system as an expanding machine. The shape of the modified scroll expander case is a rectangular parallelepiped and the size of the case is $0.0394m^3$. The scroll expander is operated in an ORC using R245fa as working fluid with various working conditions for the performance test. The test data points are used to calculate the parameters of the scroll expander semi-empirical simulation model. The simulation results are compared with the experimental results to validate the simulation model.

Study on Organic Rankine Cycle (ORC) for Maximum Power Extraction from Low-Temperature Energy Source (저온 열원으로부터 최대 동력을 생산하기 위한 유기랭킨사이클(ORC)에 관한 연구)

  • Kim, Kyoung-Hoon;Han, Chul-Ho;Kim, Gi-Man
    • Journal of the Korean Solar Energy Society
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    • v.31 no.3
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    • pp.73-79
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    • 2011
  • ORC(organic Rankine cycle) has potential of reducing consumption of fossil fuels and has many favorable characteristics to exploit low-temperature heat sources. This work analyzes performance of ORC with superheating using low-temperature energy sources in the form of sensible energy. Maximum mass flow rate of a working fluid relative to that of a source fluid is considerd to extract maximum power from the sources. Working fluids of R134a, $iC_4H_{10}$ and $C_6C_6$, and source temperatures of $120^{\circ}C$, $200^{\circ}C$ and $300^{\circ}C$ are considered in this work. Results show that for a fixed source temperature thermal efficiency increases with evaporating temperaure, however net work per unit mass of source fluid has a maximum with respect to the evaporating temperature in the range of low source temperature. Results also show that the maximum power extraction is possible with R134a for the source temperature of $120^{\circ}C$, with $iC_4H_{10}$ for $200^{\circ}C$, and with $C_6C_6$ for $300^{\circ}C$.