• Title/Summary/Keyword: Hydrogen compressor

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Performance Test of 2 kW Class Reverse Brayton Refrigeration System (냉동능력 2 kW 급 역브레이튼 극저온 냉각시스템 성능시험)

  • KO, JUNSEOK;LEE, KEUN-TAE;PARK, SEONG-JE;KIM, JONGWOO;CHOO, SANGYOON;HONG, YONG-JU;IN, SEHWAN;PARK, JIHO;KIM, HYOBONG;YEOM, HANKIL
    • Transactions of the Korean hydrogen and new energy society
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    • v.31 no.5
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    • pp.429-435
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    • 2020
  • This paper describes the experimental study of reverse-Brayton refrigeration system for application to high temperature superconductivity electric devices and LNG re-liquefaction. The reverse-Brayton refrigeration cycle is designed with operating pressure of 0.5 and 1.0 MPa, cooling capacity of 2 kW at 77 K, and neon as a working fluid. The refrigeration system is developed with multi scroll compressor, turbo expander and plate heat exchanger. From experiments, the performance characteristics of used components is measured and discussed for 77-120 K of operating temperature. The developed refrigeration system shows the cooling capacity of 1.23 kW at 77 K and 1.64 kW at 110 K.

Rotordynamic Analysis and Operation Test of Turbo Expander with Hydrostatic Bearing (정압베어링을 적용한 터보팽창기의 회전체 동역학 해석 및 구동시험)

  • Lee, Donghyun;Kim, Byungock;Jung, Junha;Lim, Hyungsoo
    • Tribology and Lubricants
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    • v.38 no.2
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    • pp.33-40
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    • 2022
  • In this study, we present rotor dynamic analysis and operation test of a turbo expander for a hydrogen liquefaction plant. The turbo expander consists of a turbine and compressor wheel connected to a shaft supported by two hydrostatic radial and thrust bearings. In rotor dynamic analysis, the shaft is modeled as a rigid body, and the equations of motion for the shaft are solved using the unsteady Reynolds equation. Additionally, the operating test of the turbo expander has been performed in the test rig. Pressurized helium is supplied to the bearings at 8.5 bar. Furthermore, we monitor the shaft vibration and flow rate of the helium supplied to the bearings. The rotor dynamic analysis result shows that there are two critical speeds related with the rigid body mode under 40,000 rpm. At the first critical speed of 36,000 rpm, the vibration at the compressor side is maximum, whereas that of the turbine is maximum at the second critical speed of 40,000 rpm. The predicted maximum shaft vibration is 3 ㎛, whereas sub-synchronous vibration is not presented. The operation test results show that there are two critical speeds under the rated speed, and the measured vibration value agrees well with predicted value. The measured flow rate of the helium supplied to the bearing is 2.0 g/s, which also agrees well with the predicted data.

Performance of the Geothermal Heat Pump using Vapor Injection for Hot Water (증기분사를 적용한 고온수용 지열 히트펌프의 성능특성)

  • Park, Yong-Jung;Park, Byung-Duck
    • Transactions of the Korean hydrogen and new energy society
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    • v.25 no.3
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    • pp.297-304
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    • 2014
  • The purpose of this study is to evaluate the experimental performance characteristics of a water-to-water geothermal heat pump featuring a vapor refrigerant injection for the production of hot water. The performance of geothermal heat pump with a vapor injection was evaluated by comparing with that of a conventional geothermal heat pump without a vapor injection. For heating operation, the geothermal heat pump with a vapor injection is superior in COP and heating capacity. The vapor injection was more effective for supplying hot water while overloading. The vapor injection was effective for the improvement of the cooling capacity. However, the vapor injection was not effective for the increasing of COP according to the increased input of a compressor. The advantage of vapor injection in water-to-water geothermal heat pump become disappeared while cooling operation with lower part loading.

CFD and Experimental Study of Gas Flow inside the Wounding Steel Pipe Fitted in Reciprocating Hydrogen Compressor (왕복동식 수소 압축기의 강관 관로 내부 가스흐름의 CFD와 실험)

  • Chung, H.S.;Rahman, M. Sq.;Lee, G.H.;Woo, J.S.;Kim, B.H.;Jeong, H.M.
    • Journal of Power System Engineering
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    • v.14 no.3
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    • pp.25-32
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    • 2010
  • 전 세계적으로 급속도로 인기가 더해가고 있는 수소에너지는 높은 전환 효율성, 재생성, 친환경적인 특징을 가지며 미래의 주 에너지가 될 것이다. 왕복동식 압축기를 통과한 후의 수소 가스의 압력은 높은 맥동압을 가진다. 스너버는 압축기의 한 구성품으로 맥동압을 낮추고 수소가스의 불순물을 제거하기 위해 사용된다. 이 연구에서의 실험은 스너버 시스템에 사용된 강관의 맥동에 관해 조사하기 위해서 수행되었다. 맥동압은 12 Hz ~ 60 Hz의 모터속도에서 RMS값을 기준으로 0.1625% ~ 0.5305% 그리고 평균압력을 기준으로 0.1621% ~ 0.5277% 감소하였다. 압력손실은 RMS값을 기준으로 0.1092% ~ 1.4419%, 평균압력을 기준으로 0.1493% ~ 1.7507%로 측정되었다. CFD를 이용한 수치해석값은 실험값이 거의 비슷한 결과를 나타내고 강관 관로 내부 가스의 자세한 압력을 설명하기 위한 중요한 역할을 수행한다.

Exergy Analysis of Gas Turbine System Depending on Steam Injection Method (증기 분사 방식에 따른 가스터빈 시스템의 엑서지 해석)

  • MIJIDDORJ, DASHTSEDEN;LIM, SOK KYU;JUNG, YOUNG GUAN;KIM, KYOUNG HOON
    • Transactions of the Korean hydrogen and new energy society
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    • v.28 no.5
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    • pp.570-576
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    • 2017
  • Gas turbine system with steam injection has shown outstanding advantages such as high specific power and NOx reduction. In the present work, a comparative exergetic analysis was carried out for Steam Injected Gas Turbine (STIG), Regenerative Steam Injected Gas Turbine (RSTIG), and Regenerative After Fogging Gas Turbine (RAF). Effects of pressure ratio, steam injection ratio and steam injection method on the system performance was theoretically investigated. The results showed that the order of the highest exergy efficiency is RSTIG, RAF, and STIG for low pressure ratios but STIG, RSTIG, and RAF for high pressure ratios. In each arrangement, the combustion chamber has the highest exergy destruction and the compressor has the second one.

Performance Characteristics of a Cascade Refrigeration System with Internal Heat Exchanger using Carbon Dioxide (R744) and Propane (R290) (내부 열교환기 부착 $CO_2-C_3H_8$용 캐스케이드 냉동시스템의 성능 특성)

  • Son, Chang-Hyo
    • Transactions of the Korean hydrogen and new energy society
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    • v.20 no.6
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    • pp.526-533
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    • 2009
  • In this paper, cycle performance analysis of $CO_2-C_3H_8$ (R744-R290) cascade refrigeration system with internal heat exchanger is presented to offer the basic design data for the operating parameters of the system. The operating parameters considered in this study include subcooling and superheating degree and gas cooling pressure and evaporating temperature in the propane (R290) low temperature cycle and the carbon dioxide (R744) high temperature cycle. The main results were summarized as follows : The COP of cascade refrigeration system of $CO_2-C_3H_8$ (R744-R290) increases with the increasing subcooling degree, but decreases with the increasing superheating degree. The COP of cascade refrigeration system increases with the increasing evaporating temperature, but decreases with the increasing gas cooling pressure. Therefore, superheating and subcooling degree, compressor efficiency, evaporating temperature and gas cooling pressure of $CO_2-C_3H_8$ (R744-R290) cascade refrigeration system have an effect on the COP of this system.

Effect of Carbon Capture Using Pre-combustion Technology on the Performance of Gas Turbine Combined Cycle (연소전 처리를 이용한 탄소포집이 가스터빈 복합화력 플랜트의 성능에 미치는 영향)

  • YOON, SUKYOUNG;AHN, JIHO;CHOI, BYEONGSEON;KIM, TONGSEOP
    • Transactions of the Korean hydrogen and new energy society
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    • v.27 no.5
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    • pp.571-580
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    • 2016
  • In this paper, performance of the gas turbine combined cycle(GTCC) using pre-combustion carbon capture technology was comparatively analysed. Steam reforming and autothermal reforming were used. In the latter, two different methods were adopted to supply oxygen for the reforming process. One is to extract air form gas turbine compressor (air blowing) and the other is to supply oxygen directly from air separation unit ($O_2$ blowing). To separate $CO_2$ from the reformed gas, the chemical absorption system using MEA solution was used. The net cycle efficiency of the system adopting $O_2$ blown autothermal reforming was higher than the other two systems. The system using air blown autothermal reforming exhibited the largest net cycle power output. In addition to the performance analysis, the influence of fuel reforming and carbon capture on the operating condition of the gas turbine and the necessity of turbine re-design were investigated.

Optimization study on fuel cell cathode oxygen flow path for Unmanned Aerial Vehicle using computational visualization (전산 가시화를 통한 무인 항공기용 연료전지 양극 산소 유로 최적화 연구)

  • Jeon, Ji-A;Lee, Jae-Jun;Song, Young-Su;Kim, Min-Su;Kim, Gun Woo;Na, Youngseung;Rhee, Gwang Hoon
    • Journal of the Korean Society of Visualization
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    • v.17 no.1
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    • pp.85-92
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    • 2019
  • Numerical visualization is conducted to confirm the variation of flow characteristics and pressure drop by the shape of channels on the cathode flow path in hydrogen fuel cells for unmanned aerial vehicles(UAVs). Generally, a light-weight fan is commonly used rather than a heavy air compressor at UAVS. However, in case of blower fan, a large pressure drop in the flow path causes the blocking of the oxygen supply to the fuel cell. Therefore, the uniformity of flow inside the cathode has to be achieved by changing the shape of the cathode. The flow channel, the duct shape, and the diameter of the fan are changed to optimize the flow path. As a result, it is confirmed that the optimal flow path can decrease the velocity difference between the center and outer flow by 1.8%. However, It should be noted that the channel size can increase the pressure drop.

Performance of the Geothermal Heat Pump Using HFC32 Refrigerant (HFC32 냉매를 사용한 지열원 히트펌프의 성능 특성)

  • PARK, YONG-JUNG;PARK, BYUNG-DUCK
    • Transactions of the Korean hydrogen and new energy society
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    • v.30 no.4
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    • pp.369-375
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    • 2019
  • Air conditioners adopting high energy efficiency and low global warming potential (GWP) refrigerant are being developed globally. In case of commercial air conditioner, R32 with lower GWP than R410A is attracting industrial attentions. In this study, the performance of water-to-water geothermal heat pump adopting R32 is compared with that of the heat pump using R410A. By using R32 instead of R410A, heating capacity and COP in heating standard condition can be increased by 8.8% and 6.3% respectively. Also, cooling capacity and COP in cooling standard condition can be increased by 5.3% and 3.1% respectively by using R32. But in case of using R32, systemic improvements are required to decrease discharge temperature of compressor since discharge temperature rises abnormally in heating operations.

Process Analysis and Simulation for System of Air Liquefaction Separation Using LNG Cold Energy (LNG 냉열을 이용한 공기액화분리시스템의 시뮬레이션 및 공정 해석)

  • HAN, DANBEE;BAEK, YOUNGSOON
    • Transactions of the Korean hydrogen and new energy society
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    • v.30 no.3
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    • pp.276-281
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    • 2019
  • The process of separating oxygen and nitrogen from the air is mainly performed by electric liquefaction, which consumes a lot of electricity, resulting in higher operating costs. On the other hand, when used for cold energy of LNG, electric power can be reduced compared to the electric Linde cycle. Currently, LNG cold energy is used in the cold refrigeration warehouse, separation of air-liquefaction, and LNG cold energy generation in Japan. In this study, the system using LNG cold energy and the Linde cycle process system were simulated by PRO/II simulators, respectively, to cool the elevated air temperature from the compressor to about $-183^{\circ}C$ in the air liquefaction separation process. The required amount of electricity was compared with the latent heat utilization fraction of LNG, the LNG supply pressure, and the LNG cold energy usage. At the air flow rate of $17,600m^3/h$, the power source unit of the Linde cycle system was $0.77kWh/m^3$, compared with $0.3kWh/m^3$.