• 설비공학논문집
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• 제10권6호
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• pp.683-694
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• 1998

The application of hydrocarbon refrigerants in a hermetic reciprocating compressor for refrigerator is investigated. The selected refrigerants are isobutane(R600a), propane(R290), R12, binary mixture of R600a/R290, and OS-21CII. Both theoretical and experimental investigations have been performed for the selected refrigerants. The test results of hydrocarbon refrigerants have been compared to the traditional refrigerant(R12). The results show that hydrocarbon refrigerants(HC-Blend, OS-21C II) are very good alternatives in the refrigeration system for R12.

• 설비공학논문집
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• 제11권2호
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• pp.262-269
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• 1999

The application of hydrocarbon refrigerant mixtures in a hermetic reciprocating compressor for dehumidifier is investigated. The selected refrigerants are R12, R134a, HC-Blend (R290/R600a), CX(R152a/R600a) and OS-l2a. Both theoretical and experimental investigations have been performed for the selected refrigerants. The test results of hydrocarbon refrigerants have been compared to traditional refrigerant(R12) and R134a. The results show that hydrocarbon refrigerant mixtures(HC-Blend, CX and OS-l2a) are very good alternatives in the refrigeration system for R12 and R134a.

• 대한기계학회논문집
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• 제17권2호
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• pp.475-483
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• 1993

A computer simulation model of a hermetic reciprocating type of refrigeration compressor has been developed. The compressor simulation model constitutes 6 control volumes, to each of which conservation laws of mass and energy are applied to yield full description of the refrigerant state along its passage. Instead of ideal gas assumption. real gas equation is employed. Some of valve-related input data required for the simulation are acquired from test bench experiments. The refrigerant states such as pressure and temperature, etc., mass flow rates, and valve motions can be predicted by the simulation. The calculated P-V diagram shows a good agreement with experimental result.

• 대한기계학회논문집B
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• 제22권7호
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• pp.966-979
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• 1998

Thermodynamic and dynamic analysis has been conducted to investigate performance variations induced by substitution of alternative refrigerants, HFC134a or HC600a for CFC12 in hermetic reciprocating compressors. For the thermodynamic analysis, mass and energy conservation laws are applied to the cylinder volume and Helmholtz resonator modeling method is adopted to describe gas pulsations at suction and discharge system. The modeling of the dynamics of the compressor mechanism has been performed with lumped mass method to analyse the bearing loads and friction losses at each bearing. To verify the correctness of this analysis, results of the performance simulation have been compared to those of calorimetric measurrements of compressor operating with CFC12. Analysis of the various losses, noise and reliability as well as performance has been conducted to present the design guideline for the compressor development with alternative refrigerants. It is found that compressors with alternative refrigerants, HFC 134a or HC600a give better COPs than those with CFC12 under the same operating conditions and especially, compressors with HC600a show better reliability and noise characteristics also.

• 한국소음진동공학회논문집
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• 제20권2호
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• pp.153-159
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• 2010

This work focuses on finding a method to reduce the noise of a hermetic reciprocating compressor during start-up using an acoustical analysis. The noise of compressor during start-up, which is a higher level than that of a normal operating condition, has transient and non-stationary characteristics. The acoustical analysis of compressor cavity is performed to find an effective method to reduce the noise level. In the acoustical analysis, the shape variations of frequency response function in the neighborhood of resonances are tested for three parameters: the height of remained oil, the suction position of refrigerant and the position of driving part. As a conclusion of this result, to reduce the emission noise of compressor during start-up, the height of remained oil should be kept at 16 mm, the refrigerant should be sucked at the cross point of nodal lines of X and Y directional cavity modes, and the driving part should be positioned in the center of cavity.

• 연구논문집
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• 통권34호
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• pp.39-46
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• 2004

The compressors in the air conditioner have the role of the pressurization and circulation of the refrigerant. The hermetic reciprocating compressors driven by rotary motor have been used for the air conditioner. The linear compressor has very simple structure and enhancement in the efficiency in comparison to that of conventional reciprocating compressor. The linear compressors are widely used for the small cryogenic refrigerator (below 1 kW), such as the Stirling refrigerator and pulse tube refrigerator. In the cryogenic application, the pressure ratio of the linear compressor is below 1.5, but the linear compressor for the air conditioner should overcome the high pressure ratio and the large pressure difference between the each sides of the piston. The resonance characteristics of the linear compressor has the significant impacts on the power consumption. To minimize the power consumption, the linear compressor should be operated at the resonance point. In the resonance characteristics, the role of the mechanical and gas spring should be considered. In present study, the cycle of the analysis of the vapor compression refrigeration cycle with the different refrigerants (R134a, R4l0a, R600a) and the designs of the linear compressor are performed. The effects of the stiffness of the mechanical spring on the electromagnetic forces would be discussed. Finally, the results show the design specification of the linear compressor for the air conditioner.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.1162-1167
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• 2001

Suction valve fluttering is generated by reciprocating motions of the piston inhaling and discharging process of gas in the hermetic compressor. A reactive type suction muffler, which produces high pressure-drop because of its complicated flow path, controls the impulsive noise radiated from the flutter of suction valve. The high-pressure drop in the muffler increases the transmission loss, but reduces the EER(Energy Efficiency Ratio) of the compressor. We consider how to design the high acoustic attenuation and low pressure-drop performance to take account of the acoustic and flow performances of the suction muffler. In this study, we identified the suction noise source of compressor from the measurement of the acoustic pulsation and flutter of suction valve. We analyzed the acoustic characteristics of muffler using the finite element method, and compared the experimental and analytical characteristics of flow path of suction muffler. Theoretical predictions and experimental results are compared from the viewpoint of the acoustic performance and energy efficiency of the compressor.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.17-24
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• 1998

압축기의 종류는 크게 dynamic type과 positive displacement type으로 우선 나눌 수 있다. 전자는 제트엔진에 사용되는 압축기에서 보는 바와 같이 기체의 속도를 변화시켜 동압을 정압으로 바꾸어 압력을 얻는 경우이다. 후자는 기체를 둘러싼 체적을 줄여서 압력을 얻는데 가전제품에 쓰이는 냉각용 압축기의 대부분의 종류가 이에 해당된다. 압축 기체의 종류에 따라 공기 압축기, 가스 압축기, 냉각용 압축기로도 나눌 수 있겠다. 냉각용 압축기는 다시 여러 가지 방법으로 분류할 수 있겠지만, 구동 모타의 용량이나 냉각 용량에 따라, 대형, 소형으로 분류하거나, 압축기를 둘러싼 셀의 구조에 따라 밀폐형과 반 밀폐형으로 나눌 수 있다. 밀폐형은 냉매를 반 영구적으로 보충할 필요가 없도록 용접형 셀을 가진 구조로 압축기를 다시 열어서 보수할 수가 없다. 냉장고나 냉방기 같은 가전 제품에 쓰이는 압축기는 대부분 소형 밀폐형이 되겠다. 산업용의 중,대형 압축기는 보수의 목적으로, 자동차 냉방용 압축기는 동력이 엔진축에서 공급되는 구조 상의 이유로 반 밀폐형이 채택된다. 보수가 사실상 불가능한 밀폐형의 구조 상 소형 냉장용 압축기는 거의 무한 수명을 감안한 설계를 요하게 되고, 이것이 압축기의 보수적인 설계 및 개발 성향에 어느 정도 영향을 주었다고 볼 수 있다. 이런 소형 밀폐형 압축기(positive displacement, fractional horsepower, hermetic compressor)에 관한 연구의 소개가 이 글의 주 관심이 되겠다. 압력을 얻기 위해 체적을 변화시키는 mechanism도 여러 가지가 있는 바, 왕복동식 피스톤(reciprocating piston) 압축기가 가장 오랫동안 사용되어 온 구조이다. 회전식으로 압축을 얻는 방식으로는 로타리 피스톤식, 스크류식, 스크롤식 압축기가 있다. 로타리 피스톤(rotary piston)식 압축기는 약 20여년 전 부터 냉방용 압축기에서부터 널리 쓰이게 되었다. 약 10여년전부터 상용화 된 스크롤(scroll) 형 압축기도 현재 상대적으로 용량이 큰 가정용 냉방기를 중심으로 많이 쓰이고 있다. 스크류형 압축기는 보통 중대형 상업용에 주로 쓰인다.