• 동력기계공학회지
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• 제21권5호
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• pp.5-12
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• 2017

With the difficulties in increasing the efficiency of conventional crank-driven compressors due to mechanical loss, compressor manufacturers have investigated new kinds of compressor such as a free piston compressor mechanism. This study investigates the energy efficiency of two different types of compressor for a household refrigerator. One is the conventional crank-driven compressor, and the other one is a linear compressor. The energy efficiencies of these compressors are evaluated. Experimental results show that the linear compressor has 10% lower power consumption than the brushless direct-current (BLDC) reciprocating compressor. The linear compressor demonstrates excellent energy efficiency by reducing the friction loss. Furthermore, a motor efficiency exceeding 90% is achieved by using a linear oscillating mechanism with a moving magnet. Additionally, the compressor stroke to piston diameter ratio of the oscillating piston in the linear compressor can be adjusted in order to modulate the cooling capacity of the compressor for improved system efficiency.

• 한국수산과학회지
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• 제12권1호
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• pp.13-18
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• 1979

Volumetric efficiency is a determining factor for tile measurement of compessor capacity, but it is practically hard to take an accurate measurement of capacity characteritics so that most of users trust the data of makers catalogue. We often realized the discrepancy in their data with actual capacity. This study was attemped to establish the basic data of capacity characteristics of compressor by measuring volumetric efficiency of high speed multi-cylinder compressor and rotary compressor. The volumetric efficiency was calculated based on the quantity of the flow of ammonia vapor and pressure difference in suction state of orifice plate and compressor. The volumetric efficiency of high speed multi-cylinder compressor was $37-61\%$ and that of rotary compressor was $57-82\%$ when compression ratio was in the range of 4-12. The discrepancy in volumetric efficiency at an equal evaporating temperature between the makers catalogue and the measured data was $5.5\%$.

• International Journal of Fluid Machinery and Systems
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• 제3권3호
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• pp.260-270
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• 2010

Reducing the losses of the tip clearance flow is one of the keys in an unshrouded centrifugal compressor design and development because tip clearances are large in relation to the span of the blades and also centrifugal compressors produce a sufficiently large pressure rise in single stage. This problem is more acute for a low flow high-pressure ratio impeller design. The large tip clearance would cause flow separations, and as a result it would drop both the efficiency and surge margin. Thus a design of a high efficiency and wide operation range low flow coefficient centrifugal compressor is a great challenge. This paper describes a recent development of high efficiency and wide surge margin low flow coefficient centrifugal compressor. A viscous turbomachinery optimal design method developed by the authors for axial flow machine was further extended and used in the centrifugal compressor design. The compressor has three main parts: impeller, a low solidity diffuser and volute. The tip clearance is under a special consideration in this design to allow impeller insensitiveness to the clearance. A patented three-dimensional low solidity diffuser design method is used and applied to this design. The compressor test results demonstrated to be successful to extend the low solidity diffusers to high-pressure ratio compressor. The compressor stage performance showed the total to static efficiency of the compressor being about 85% and stability range over 35%. The test results are in good agreement with the design.

• 설비공학논문집
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• 제17권5호
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• pp.418-426
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• 2005

Efficiency of the compressor is most important parameter in the domestic refrigerator which runs year around. With developed analytical model about heat transfer analysis in the hermetic compressor, parametric study was performed to know the effect on efficiency by design and material modification of the compressor. Volumetric efficiency of the compressor increased approximately $3\%$ when insulation is increased about $50\%$ in suction component. However, the insulation effect on discharge component was only $1\%$. When the thermal conductivity of the discharge plenum is reduced from 300 to 20 $W/m{\cdot}K$, volumetric efficiency increased about $3.1\%$. There is no attraction in efficiency increment with variation of outside surface area of the compressor and radial heat transfer coefficient of the solid component in the compressor shell.

• 드라이브 ㆍ 컨트롤
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• 제17권2호
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• pp.38-44
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• 2020

Various efforts have been initiated to reduce the energy consumption of the compressor as it is one of the approaches to saving a large portion of the fixed cost of the production site. Various results of reducing the energy consumption of the compressor have been reported, but to reduce the energy consumption of the compressors fundamentally, regular management of the compressor should ensure optimum operation. This requires periodic on-site visits by experts, but is often overlooked as a cost issue, resulting in the use of the compressor in low-efficiency conditions. Thus, it is necessary to develop a low-cost evaluation technology for compressor condition monitoring and efficiency analysis to ensure that the compressor is always driven at the optimum efficiency without imposing undue burden on the compressor user. In this study, a sensor was installed at the inlet, outlet, and power supply of the compressor, and a method for evaluating the energy consumption of the compressor using the minimum sensor was derived. The experimental results are presented to show the validity of the proposed method. It was confirmed that the energy consumption of the compressor can be easily as well as efficiently evaluated by using the method developed in this study.

• 설비공학논문집
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• 제10권2호
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• pp.173-179
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• 1998

An experimental study was conducted on the effect of compressor capacity control range of heat pump on the seasonal energy efficiency ratio with variation of the maximum and minimum compressor input frequencies. To obtain seasonal energy efficiency ratio, steady state test at the maximum, minimum and intermediate compressor speed and cyclic test at the minimum compressor speed should be conducted. Maximum input frequency was varied to 95Hz, 105Hz, and 115Hz, and the minimum input frequency was varied to 35Hz, 45Hz, and 55Hz. The seasonal energy efficiency ratio increased as the input frequency of the compressor decreased. The maximum input frequency had only slight effects on the SEER.

• 설비공학논문집
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• 제18권4호
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• pp.351-358
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• 2006

This paper presents analytical results of a rotary vane compressor performance when the compressor is used for air supply from underwater. Compression characteristics such as pressure and temperature in a compression chamber are analyzed. Volumetric and adiabatic efficiencies are calculated. Vane dynamics are also performed to give reaction forces on the vane from the cylinder inner surface and from vane slots. Compressor efficiency is about 34.9%, and about 55% of the compressor loss is produced by the friction between the vane nose and the cylinder wall. Volumetric efficiency is about 79.5%, and indicated efficiency is about 77.1%, which are comparable to other displacement type compressors. When roller was introduced between housing inner wall and vane tips, mechanical efficiency could be improved by as much as 24.9%, depending on the roller friction.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.215-220
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• 2002

This paper describes a simulation model for estimation the performance of the swash plate type compressor for automotive air conditioning system. The model includes consideration of both the compression process and the dynamic behavior. Also, this study compares the results obtained from the performance simulation with experimental results. Further, the effects of the inclined angle of swash plate on the performance of swash plate type compressor are discussed.

• 한국기계가공학회지
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• 제20권6호
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• pp.70-75
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• 2021

Recently, several efforts have been made to improve the thermal efficiency of a refrigerant compressor. In this study, we attempted to improve energy efficiency ratio (EER) performance by reducing the superheat of the linear compressor. To this end, heat generated inside the compressor must be effectively dissipated. Therefore, heat dissipation was improved by processing ribs in the gap-flow region generated owing to the vibration of the compressor body. The results showed that the convective heat transfer coefficient becomes significantly high when ribs are used, increasing the heat dissipation rate. This helps improve EER by reducing the superheat of the compressor.

• 전기학회논문지
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• 제62권11호
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• pp.1544-1549
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• 2013

Recently, the linear compressors with the free piston driven by the linear motor have widely attention in the cooling apparatus such as a refrigerator due to high efficiency. The method of using triacs as a linear motor drive is not satisfactory to improve the efficiency of the linear compressor. In this paper, the performance of the linear compressor using a PWM inverter such as the efficiency is investigated with the variations of both mechanical resonant frequency and electrical resonant frequency. The control loop for controlling both the piston stroke and efficiency is suggested. Through simulation and experimental studies, the performance of both the stroke and angle controls for improving the efficiency of the linear compressor is verified.