• Title/Summary/Keyword: Air Compressor

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Development of a Switched Reluctance Motor-based Electric AC Compressor Drive for HEV/EV Applications

  • Kim, Jaehyuck;Jeong, Yong-Hoe;Jeon, Yong-Hee;Kang, Jun-Ho;Lee, Seunghun;Park, Jang-Yeop
    • Journal of Magnetics
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    • v.19 no.3
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    • pp.282-290
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    • 2014
  • This paper discusses the development of a 3.5 kW switched reluctance motor (SRM)-based electric air-conditioning (AC) compressor, focusing primarily on the design aspects of the SRM and the integrated controller. In addition to the increased price of rare-earth magnets, SRM's operation capability at high speed and high temperature makes the SRM a viable alternative to the permanent magnet motor for electrically driven automotive air conditioning compressors. A compact and energy efficient scroll compressor is designed and constructed. Two feasible SRM topologies are considered, in terms of efficiency, torque ripple, and acoustic noise. Compact drive electronics are designed and employed to drive the SRM-based compressor. The static and dynamic performance is validated by simulation and experiment.

Benchmark Performance Analysis of Vapor Compression System with Capacity Modulation Compressor (에어컨의 고효율화를 위한 용량가변 방식 비교에 관한 연구)

  • 유윤호;황윤제;김철민;조관식
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.14 no.2
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    • pp.98-107
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    • 2002
  • The performance of a capacity controlled system, which are tandem, pole change, bypass and inverter driven compressor, has been compared with that of a con- ventional constant speed system. It has been found that capacity modulated system can offer more than 14 percent improvement in SEER over the conventional system. Comparative test results show that two compressor system can attain an improvement in SEER up to 42% over the conventional on/off system, and is feasible without additional investment.

A Numerical Study of Liquid Injection into the Compressor Cylinder of a Heat Pump (열펌프 압축기의 내부 액분사 효과에 대한 수치해석적 연구)

  • 허재경;방광현
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.5
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    • pp.397-405
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    • 2003
  • Heat and fluid flow in a compressor into which liquid refrigerant is injected for the purpose of reducing discharge gas temperature in a heat pump system has been numerically studied. A mechanistic approach encompassing liquid jet breakup and droplet evaporation has been performed to investigate the effects of liquid injection on the spacial and temporal variation of the gas temperature and pressure inside the compressor cylinder. Various parameters, such as liquid injection mass, time, duration and droplet size, are considered in the present study to elucidate the flow field inside the compressor. As the injection mass is increased, discharge gas temperature is decreased, while the pressure is increased due to the added mass of the injection. For the injected liquid mass corresponding to 15% of the total vapor mass in the cylinder, the discharge gas temperature drops by 22.4 K. It is observed that the droplet size plays a major role in the evaporation rate of the droplets that determines the degree of the discharge temperature drop.

Sensorless Control for a PM Synchronous Motor in a Single Piston Rotary Compressor

  • Cho Kwan-Yuhl
    • Journal of Power Electronics
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    • v.6 no.1
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    • pp.29-37
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    • 2006
  • A sensorless control for an IPM (Interior Permanent Magnet) synchronous motor in a single piston rotary compressor is presented in this study. The rotor position is estimated from the d-axis and q-axis current errors between the real system and a motor model of the position estimator. The torque pulsation of the single piston rotary compressor is compensated to reduce speed ripples, as well as, mechanical noise and vibration. The proposed sensorless drive enables the compressor to operate at a lower speed which increases energy savings and reduces mechanical noise. It also gives high speed operations by a flux weakening control for rapid air-cooling and heating of the heat pump air-conditioners.

Optimum Design of $CO_2$ Scroll Compressor for Heat Pump Water Heater (급탕기용 열펌프를 위한 $CO_2$ 스크롤 압축기 최적설계에 관한 연구)

  • 김현진;안기정;김철우
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.3
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    • pp.241-249
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    • 2004
  • A parametric study on the scroll wrap configuration factors of a $CO_2$scroll compressor for heat pump water heater has been carried out. Since there are 7 scroll wrap design parameters and 5 equations relating them, two of the design parameters can be selected as independent parameters. In this study, the wrap thickness and orbiting radius are chosen as independent ones. Computer simulation program has been used to estimate the compressor performance at various combinations of the scroll wrap design parameters. It has been found that there exists optimum combination of the wrap parameters for the highest compressor performance over analyzed ranges of the design parameters.

Analysis of relative contribution of machinery-induced vibration/flow-induced vibration to noise radiation from compressor discharging piping system in air-conditioner outdoor unit (에어컨 실외기 압축기 배기 배관계의 기기 기인 진동/유동 기인 진동의 방사소음에 대한 상대적 기여도 분석)

  • Sangheon Lee;Cheolung Cheong;Jinhyung Park;Jangwoo Lee
    • The Journal of the Acoustical Society of Korea
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    • v.43 no.1
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    • pp.122-130
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    • 2024
  • Vibration of compressor in the air-conditioner outdoor unit have known to be main noise source radiated from outdoor unit. However, as the operating speed of compressor increase, the relative contribution of flow induced vibration and noise is also increase. In this paper, the numerical method was established to predict fluid-borne noise from compressor discharging pipe of air-conditioner outdoor unit. In this step, numerical result was compared to experimental one to verify numerical method. Additionally, the effects of pressure pulsation of compressor and compressor vibration into radiated noise were investigated in frequency domain. It was confirmed that the compressor vibration contributed to the low frequency band, while the pressure pulsation dose to the high frequency band.

Effect of Outdoor Temperature on the Refrigerant Behavior in the Compressor of a Heat Pump Operating at Heating Mode (열펌프의 난방운전시 외기온이 압측기의 냉매거동에 미치는 영향)

  • 이재효;김병균;이건우
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.5
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    • pp.452-458
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    • 2004
  • The major cause of compressor failure is the decrease of oil viscosity due to floodback. In most previous researches on the compressor reliability, the relationship between oil circulation rate and performance or oil viscosity has been studied. Another research topic is flow visualization by using a sight glass on the bottom of a compressor sump area and accumulator. Both oil film thickness and oil level through the sight glass should be assessed for compressor reliability if the oil content of the mixture is small and low viscosity raise poor lubrication of pump bearing. In this study, the compressor reliability was assessed by measuring the viscosity of the mixture and calculating oil film thickness. The analysis of the relationship between bottom shell super heat and oil film thickness at heating operation was peformed. It is concluded that bottom shell superheat does not perfectly stand for the mixture's behavior for a low ambient heating operation and oil film thickness can give more detailed and direct criteria for compressor reliability.

The lubrication Characteristics of a Rotary Compressor used for Refrigeration and Air-conditioning Systems Park II: Analysis of elastohydrodynamic lubrication on vane tip (냉동${\cdot}$공조용 로터리 콤프레서의 윤활 특성 제2보:베인 선단부의 탄성 유체 윤활 특성 해석)

  • Cho, Ihn-Sung;Oh, Seok-Hyung;Jung, Jae-Youn
    • Tribology and Lubricants
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    • v.13 no.1
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    • pp.62-69
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    • 1997
  • Rapid increase of refrigeration and air-conditioning systems 9r & a systems) in modern industries brings attention to the urgency of research & development as a core technology in the area. And it is required to the compatibility problem of r & a systems to alternative refrigerant for the protection of environment. The, it is requested to study the lubrication characteristics of refrigerant compressor which is the core technology in the r & a systems. The study of lubrication characteristics in the critical sliding component is essential for the design of refrigerant compressor. Therefore, theoretical investigation of the lubrication characteristics of rotary compressor for r & a systems is studied. The newton-Raphson method is used for the EHL analysis between vane and rolling piston in the rotary compressor. The results show that the rotational speed of a shaft and the discharge pressure influence significantly the friction force between vane and rolling piston. This results give important basic data for the further lubrication analysis and design of a rotary compressor.

Effects of Casing Shape on the Performance of a Small-sized Centrifugal Compressor

  • Kim, D.W.;Kim, H.S.;Kim, Youn-J.
    • International Journal of Air-Conditioning and Refrigeration
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    • v.11 no.3
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    • pp.132-139
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    • 2003
  • The effects of casing shapes on the performance and the interaction between an impeller and a casing in a small-sized centrifugal compressor are investigated. Especially, numerical analyses are conducted for the centrifugal compressor with both a circular casing and a volute one. The optimum design for each element (i.e., impeller, diffuser and casing) is important to develop an efficient and compact compressor using alternative refrigerant as working fluids. Typical rotating speed of the compressor is in the range of 40,000∼45,000 rpm. The impeller has backswept blades due to tip clearance and a vane diffuser has wedge type. In order to predict the flow pattern inside an entire impeller, vaneless diffuser and casing, calculations with multiple frames of reference method between the rotating and stationery parts of the domain are carried out. For computations of compressible turbulent flow fields, the continuity and time-averaged Navier-Stokes equations are employed. To evaluate the performance of two types of casings, the static pressure recovery and loss coefficients are obtained for various flow rates. Also, static pressure distributions around casings are studied for different casing shapes, which are very important to predict the distribution of radial load. The static pressure around the casing and pressure difference between the inlet and outlet of the compressor are measured for the circular casing.

Performance Comparison of Various Types of $CO_2$ Compressors for Heat Pump Water Heater Application

  • Kim, Hyun-Jin;Kim, Woo-Young;Ahn, Jong-Min
    • International Journal of Air-Conditioning and Refrigeration
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    • v.17 no.4
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    • pp.115-122
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    • 2009
  • Numerical simulations for scroll, two-stage twin rotary, and two-cylinder reciprocating compressors have been carried out to understand the effectiveness of each type compressor for heat pump water heater application using $CO_2$ as refrigerant. For suction pressure of 3.5 MPa and discharge pressure of 9 MPa, clearance volume ratio of the reciprocating compressor needs to be about 5% or less to have the volumetric efficiency comparable to that of the scroll compressor with tip clearance of $5\;{\mu}m$. Volumetric efficiency of the scroll compressor is quite sensitive to tip clearance. Adiabatic efficiency of the twin rotary compressor was calculated to be the lowest among the three types, and the most severe drawback of the $CO_2$ scroll compressor was a significant increase in the mechanical loss at the thrust surface supporting the orbiting scroll member. While the scroll compressor showed very smooth torque load variation, peak-to-peak torque variations of the twin rotary and two-cylinder reciprocating compressors were about 50% and 250%, respectively.