• 설비공학논문집
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• 제9권4호
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• pp.536-544
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• 1997

This study presents test results of a residential window system air-conditioner using R22 and two potential alternative refrigerants, R407C and R410B. A series of performance tests was performed for the basic and liquid-suction heat exchange cycle in a psychrometric calorimeter test facility. For R407C, the same rotary compressor was used as in the R22 system. However, compressor for the R410B system was modified to provide the similar cooling capacity. The evaporator circuit was changed to get a counter-cross flow heat exchanger to take advantage of zeotropic mixture's temperature glide, and liquid-line suction-line heat exchange cycle was also considered to improve the performance of the system. Test results were compared to those for the basic R22 system.

• 동력기계공학회지
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• 제10권4호
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• pp.43-49
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• 2006

Nowadays, the thermal environments of classrooms are usually adjusted by the ceiling type air-conditioning system with a temperature sensor installed on inlet of an air-conditioner. However, it is not clear that the conventional temperature sensor position is proper to satisfy both thermal comport and energy saving in summer especially. Therefore, this study is aimed at finding out the best position of the temperature sensor on the purpose of the comfort thermal environment and energy saving. The different 5 positions for the temperature sensor are supposed in this paper to analyze thermal environment by CFD. From the analysis through the CFD simulations, the best position of the temperature sensor satisfying for both comfort thermal environment and energy saving is obtained.

• 태양에너지
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• 제20권1호
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• pp.63-72
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• 2000

In this study, theoretical simulation method for the steady state characteristics of a refrigeration cycle which consists of one condenser and multi-evaporator (Multi-air conditioner) is presented. The simulation was performed for a typical multi-air conditioning system consisted one outdoor unit with air-cooled condenser, compressor, linear electric expansion valve and bypass circuit and connected three-evaporators (three indoor units). The simulation results are good agreement with those of experiments within 5 $\sim$ 10% at the given system operation conditions which are condensing pressure, evaporating pressure, sub-cooled degree of condenser, superheated degree, discharge temperature of compressor and pulse of linear electric expansion valve.

• 설비공학논문집
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• 제12권3호
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• pp.302-308
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• 2000

The major source of noise in air-conditioner is a compressor. Therefore, noise reduction in a compressor is quite significant as an element technology in air-conditioner field. Recently, a scroll compressor is widely used, because a scroll compressor features lower noise, due to less pulsation of gas pressure, than that of the rotary compressor. During a past noise reduction effort on a scroll compressor, noise radiation from the discharge portion of the hermetic shell was identified as the major contributor to overall noise. For a reduction of noise, the source of noise at the discharge portion must be identified. This paper presents detailed analyzes for the discharge pressure pulsation and cavity resonance at discharge space, which will make possible a low noise design of a scroll compressor.

• 비파괴검사학회지
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• 제21권6호
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• pp.630-633
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• 2001

본 연구에서는 국내에서 생산되는 에어콘용 팬의 진동해석을 위해 ESPI를 이용하였다. 기존의 진동해석 실험으로 많이 사용되는 가속도계를 에어콘용 팬에 직접 적용하는 데에는 형상의 제약 등으로 적용이 어려워 비접촉 진동해석기술을 요구하였다. 실험은 가진 장치를 이용하여 팬에 가진을 하고 ESPI를 이용하여 진동모드 및 고유주파수, 고유주파수의 범위를 검사하였다. 또한, 실험결과는 유한요소 해석과 비교되었으며, 실험결과로부터 실제 팬의 사용 회전수에서 제품의 신뢰성을 평가하였다 본 연구에서 사용된 ESPI는 품질개선을 위한 재질변화 또는 형상변화 시 설계측면에서 효과적인 설계정보를 제공할 수 있으며, 기존의 진동해석 기술의 단점을 보완할 수 있으리라 사료된다.

• 한국정밀공학회지
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• 제27권11호
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• pp.72-77
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• 2010

The fatigue characteristic of a material or a structure is derived from fatigue tests of standard specimens. However, many test results of standard specimens are very different from those of real structures. One reason for this difference is the constraint effects according to the geometrical difference. Therefore, to calculate more accurate fatigue life, the constraint effect must be considered by comparing test results of standard specimens with those of real structures. In this study, a blade of an air-conditioner was evaluated by both the test and the analysis. The results showed that a standard specimen is conservative, compared with a structure specimen. And fatigue life of an air-conditioner's blade was predicted from those.

• 동력기계공학회지
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• 제18권1호
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• pp.32-37
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• 2014

In this study, the optimum design process of an indoor package air-conditioner (PAC) was implemented by Taguchi method. The goal of this study is to obtain the best set condition of each control factor composing of an indoor PAC. The number of revolution of a double inlet sirocco fan installed in an indoor PAC was measured by the orthogonal array of $L_{18}(2^3{\times}3^4)$ and analysed by using the-smaller- the-better characteristic among the static characteristic analyses. As a result, the optimum condition of an indoor PAC was found as a set of when the cost of production, assembling and working conditions were considered. Moreover, the number of revolution of a double-inlet sirocco fan used for an optimum condition was reduced about 8.5% more than that of a standard condition for the target flowrate of $18.5m^3/min$.

• 한국소음진동공학회논문집
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• 제18권2호
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• pp.263-271
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• 2008

Compressor radiated noise is one of the dominant noise for the outdoor unit of the air conditioner. Therefore, air conditioner makers are trying to reduce it continuously. Even though noise absorption and isolation technology are one of the important parts for reducing the noise from the compressor, it is usually treated to the substitute technology when the noise from the compressor is very difficult to reduce by the compressor noise control only. In this paper, we focus on the property of the sound insulation for the cabinet and measure it applying the theory of the sound transmission loss and insertion loss of the simple enclosure. The insertion loss is evaluated by the experiments according to the thickness and the aperture of the partition in the cabinet.

• 태양에너지
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• 제20권4호
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• pp.45-52
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• 2000

Multi A/C is consisted of one outdoor unit and several indoor units. When the Multi Air conditioner is installed, we have to be cautious of the length of pipe arrangements. When the pipe arrangement is installed with unbalance or too long, there can be cooling capacity losses and low EER. An experimental study was carried out about the operation characteristic of Multi Air conditioner varying the length of pipe arrangements. If the pipe arrangement of the system is 15m, the cooling capacity and EER were decreased 0.8% and 1.3% respectively compared to the case when pipe arrangement is 5m. In case of 25m, the cooling capacity and EER were decreased 10.7% and 12.2% respectively compared to the case of 5m. When the length of pipe is not same each other, it is profitable to make the pipe length of highest capacity indoor unit shortest.

• 한국산학기술학회논문지
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• 제8권6호
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• pp.1325-1331
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• 2007

본 연구에서는 냉방운전 시 가변용량방식의 압축기를 적용한 시스템 에어컨의 냉방능력과 증발기 및 응축기의 온도특성을 조사하기 위해 압축기 운전율(10가지)과 실내외 온도(16가지)의 변화에 따른 시스템의 운전특성을 실험적으로 조사하였다. 시스템의 운전특성은 칼로리미터를 이용하여 측정되었다. 냉방능력은 실외온도가 낮아질수록 실내온도가 증가할수록 더 큰 값을 그리고 압축기 운전율이 증가할수록 냉방능력은 선형적으로 증가하였다. 응축온도는 실외온도 변화에 증발온도는 실내온도 변화에 더 민감하였다. 또한 압력-엔탈피선도를 이용하여 사이클의 운전특성을 분석하였다.