• Title/Summary/Keyword: Compressor Work

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Effect of Frost and Defrost on the Operating Characteristics of Refrigeration System (착상과 제상이 냉동장치의 운전특성에 미치는 영향)

  • Kim, J.D.
    • Journal of Power System Engineering
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    • v.14 no.4
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    • pp.5-10
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    • 2010
  • This study was investigated the effect on operating characteristics of apparatus according to frosting and defrosting to develop of new defrosting equipment. The results showed as following. Frost was almost removed using the defrosting equipment with roll brush type that defrosting is possible under operating condition. Also, the temperature of compressor inlet, evaporator inlet and outlet showed higher value because of heat transfer resistance of cooling pipe frost comparing with defrosting condition. And the compressor work showed 10% lower and COP was presented 24% higher values than defrosting condition. Therefore, defrosting for cooling coil of refrigeration and low temperature storage was effected on operation and performance characteristics of equipment. This highly effects on real refrigeration apparatus which is operated in year-around.

System Performance for Length and Diameter of Capillary Tube using R-1270 (모세관 길이와 관경 변화에 따른 R-1270의 성능특성)

  • Lee, Ho-Saeng;Kim, Hyun-Woo;Choi, Won-Jae;Yoon, Jung-In
    • Journal of Advanced Marine Engineering and Technology
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    • v.33 no.5
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    • pp.646-652
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    • 2009
  • Experimental results for performance characteristics of HCs refrigerant R-1270 and HCFC refrigerant R-22 during refrigeration system using capillary tube are presented. The system consists of compressor, condenser, capillary tube, evaporator and peripheral devices. Length and diameter of capillary tube are varied for this investigation. The refrigerant mass flow increased as the diameter of capillary tube increased and the length of capillary tube decreased. A refrigeration capacity and compressor work of R-1270 in same length and diameter of capillary tube showed the higher values than those of R-22. A coefficient of performance showed the highest value when the length and diameter of capillary tube are 105 cm and 1.8 mm in this experimental conditions.

A development of linear compressor for a cryogenic stirling cooler (극저온 스터링 냉동기용 선형 압축기 개발)

  • 지상우;임경화;강희석;강경태
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.731-734
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    • 2001
  • A cryogenic stirling cooler is currently under development at Korea Institute of Industrial Technology(KITECH). Cryocooler has many kinds of types. The stirling cooler is the most appropriate one for under 80K with the trait of long life cycle and small size. The stirling cooler uses helium as a working fluid. Helium is pressurized by the linear compressor which is driver by linear motor. In this paper, the change of pressure and volume is studied by the isothermal analysis method. It is necessary to investigate the optimized pressure to meets the highest COP. The compressor's piston and expender's displacer interact according to the working fluid's pressure level and the phase difference. This paper presents the relation between the initial pressure and the work of cryocooler. By that results, we can predict the performance of linear compressor.

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CFD Study on Particle Effect and Erosion in the Axial Compressor Blades and Shroud of Turbomachinery

  • Yoon J.S.;Chang Keun-Shik
    • 한국전산유체공학회:학술대회논문집
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    • 2003.10a
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    • pp.233-234
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    • 2003
  • Fly ash enters axial compressor when a turbomachinery is operated in an adverse environment. We have numerically investigated erosion of the blade and shroud in the turbulent compressor passage flow under the influence of gas-particle two-phase interaction. There have appeared quasi-three dimensional calculations on this subject but not the complete three-dimensional gas-particle interaction as done in the present work. Lagrangian particle tracing technique is used on the base of parallel processing for efficient calculation. Accuracy of the present code is tested using the benchmark lPL nozzle. In the DFVLR compressor blades, we have shown that a large number of particles passing through the tip clearance make impact on the blade tip and on the shroud. Higher degree of erosion is resulted by the heavier particles due to the centrifugal force.

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Computational Study on Particle Effect and Erosion in the Axial Compressor Blades and Shroud

  • Yoon J.S.;Chang Keun-Shik
    • 한국전산유체공학회:학술대회논문집
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    • 2003.10a
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    • pp.203-204
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    • 2003
  • Fly ash enters axial compressor when a turbomachinery is operated in an adverse environment. We have numerically investigated erosion of the blade and shroud in the turbulent compressor passage flow under the influence of gas-particle two-phase interaction. There have appeared quasi-three dimensional calculations on this subject but not the complete three-dimensional gas-particle interaction as done in the present work. Lagrangian particle tracing technique is used on the base of parallel processing for efficient calculation. Accuracy of the present code is tested using the benchmark JPL nozzle. In the DFVLR compressor blades, we have shown that a large number of particles passing through the tip clearance make impact on the blade tip and on the shroud. Higher degree of erosion is resulted by the heavier particles due to the centrifugal force.

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Experimental Study on the Performance Characteristics of an Injection Type Scroll Compressor (인젝션용 스크롤 압축기의 성능특성에 관한 실험적 연구)

  • Cho, Hong-Hyun;Kim, Yong-Chan
    • Proceedings of the KSME Conference
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    • 2000.04b
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    • pp.193-198
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    • 2000
  • For an inverter-driven compressor, the discharge temperature increased with a rise of frequency, Therefore, it is necessary to control the discharge temperature at high frequencies in order to obtain system reliability and efficiency. This paper describes the effects of liquid injection system on the performance of an inverter-driven scroll compressor. Experiments were performed at ASHRAE-T conditions. Frequency was altered from 45 to 105Hz. As results of the present work, the refrigerant discharge temperature fur the injection system was dropped approximately $10{\sim}20^{\circ}C$ as compared to those for the non-injection system. The COP of the compressor was improved approximately $0.8{\sim}9.3%$ at high frequencies(75, 90, and 105 Hz).

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Optimization of Middle Pressure and Bypass Mass Flow Rate in Cryogenic Refrigeration Cascade Cycle (초저온 케스케이드 냉동사이클의 중간압력 및 바이패스 유량 최적화)

  • Oh, S.T.;Choi, W.J.;Lee, H.S.;Yoon, J.I.;Yoo, S.I.;Choi, K.H.;Lee, S.G.
    • Journal of Power System Engineering
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    • v.14 no.2
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    • pp.28-33
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    • 2010
  • In this research, cascade liquefaction process was simulated using two-staged direct expansion with inter-cooler. Evaporated gaseous refrigerant which has low pressure and temperature from the inter-cooler is mixed with gaseous refrigerant from outlet of 1st compressor, and flows into 2nd compressor. Therefore this prevents superheating compression. Compressor work of process which includes inter-cooler to all cycles shows the lowest value of 338.68 MW and it is lower 16.34% than that of basic process. Refrigeration capacity shows decreasing tendency as applied inter-cooler and that of process which includes inter-cooler to all cycles shows the lowest value of 449 MW. COP was increased when the inter-cooler was applied, and process which includes inter-cooler to all cycles shows highest value of 1.33. It shows that COP was increased because decrement of compressor work by applying inter-cooler was higher than decrement of refrigeration capacity.

A Study of Inverse Modeling from Micro Gas Turbine Experimental Test Data (소형 가스터빈 엔진 실험 데이터를 이용한 역모델링 연구)

  • Kong, Chang-Duk;Lim, Se-Myeong
    • Journal of the Korean Society of Propulsion Engineers
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    • v.13 no.6
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    • pp.1-7
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    • 2009
  • The gas turbine engine performance is greatly relied on its component performance characteristics. Generally, acquisition of component maps is not easy for engine purchasers because it is an expensive intellectual property of gas turbine engine supplier. In the previous work, the maps were inversely generated from engine performance deck data, but this method is limited to obtain the realistic maps due to calculated performance deck data. Therefore this work proposes newly to generate more realistic compressor map from experimental performance test data. And then a realistic compressor map can be generated form those processed data using the proposed extended scaling method at each rotational speed. Evaluation can be made through comparison between performance analysis results using the performance simulation program including the generated compressor map and on-condition monitoring performance data.

A Study on the Micro Vapor Compressor based on Microfabrication Process for the Application to the Micro Miniature Refrigeration System (초소형 냉동시스템의 응용을 위한 마이크로 증기 압축기의 개발 및 성능에 관한 연구)

  • Yoon, Jae-Sung;Choi, Jong-Won;Kim, Min-Soo
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.477-482
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    • 2006
  • In this study, a micro vapor compressor has been designed, fabricated and tested. The micro vapor compressor was made of silicon substrates and fabricated by micromachining process. The compressor is driven by a piezoelectric actuator which is widely used in microfluidic systems because of its strong force and rapid response. The actuator is a bimorph structure which consists of a silicon membrane and a piezoelectric ceramic film. A simulation work was conducted on the performance characteristics of the compressor. The simulation investigated the flow rate variation under various back pressure conditions. Experimental works were carried out on the operation of a compressor and the test results were compared with the simulation results.

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Performance Analysis of a Carbon Dioxide(R744) Two-Stage Compression and One-Stage Expansion Refrigeration Cycle ($CO_2$용 2단압축 1단팽창 냉동 사이클의 성능 분석)

  • Roh, G.S.;Son, C.H.
    • Journal of Power System Engineering
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    • v.13 no.6
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    • pp.70-75
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    • 2009
  • In this paper, cycle performance analysis of R744($CO_2$) two-stage compression and one-stage expansion refrigeration system is presented to offer the basic design data for the operating parameters of the system. The operating parameters considered in this study include superheating degree, compressor efficiency, gas cooling pressure, mass flowrate ratio, outlet temperature of gas cooler and evaporating temperature in the carbon dioxide two-stage refrigeration cycle. The main results were summarized as follows : The cooling capacity of two-stage compression and one-stage expansion refrigeration system increases with the increasing superheating degree, compressor efficiency and gas cooling pressure, but decreases with the increasing mass flowrate ratio and evaporating temperature. The compression work of two-stage compression and one-stage expansion refrigeration system increases with the increasing superheating degree, outlet temperature of gas cooler, gas cooling pressure and evaporating temperature, but decreases with the increasing compressor efficiency and mass flowrate ratio. The COP of two-stage compression and one-stage expansion refrigeration system increases with the increasing compressor efficiency, but decreases with the increasing superheating degree, gas cooling pressure, mass flowrate ratio and evaporating temperature. Therefore, superheating degree, compressor efficiency, gas cooling pressure, mass flowrate ratio, outlet temperature of gas cooler and evaporating temperature of R744($CO_2$) two-stage compression and one-stage expansion refrigeration system have an effect on the cooling capacity, compressor work and COP of this system.

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