• 설비공학논문집
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• 제15권4호
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• pp.247-253
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• 2003

The new shape of louver-fin has been applied to a parallel flow condenser to enhance air-side heat transfer rate lot an automotive air-conditioner R- l34a is employed as a refrigerant inside the flat tube of the condenser, This problem is of particular interest in reducing the geometric size of the automotive air conditioner The effect of air flow rate on pressure drop as well as heat transfer in air side are studied in detail. Comparison of the performance is also made with that of a conventional parallel flow condenser, which is available in the market. The results obtained indicate that the total pressure drop through the pre sent condenser is not changed, while the heat transfer rate is increased by 24% at high veto city of air flow, compared with those of the conventional condenser. The parallel flow condenser with a new shape of louver-fin could be reduced in size by 20% for the equivalent condenser capacity, compared with the conventional parallel flow condenser.

• 설비공학논문집
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• 제28권6호
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• pp.217-223
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• 2016

In this study, we investigated the operating method of a driver for an air conditioning system according to the temperature difference between the indoor and outdoor environments of a car parked outside during the summer. Researchers of this study suggest the comfort mode of a car air conditioner to improve the thermal comfort of the driver, thereby maintaining longer comfort. This study separately, analyzed temperatures on a cloudy day and sunny day. The results showed the car indoor heat environment and physiological results (EEG, ECG) of the subject. It showed a difference of the car indoor heat environment by weather with the difference also appearing in the physiological response of the subject. In conclusion, in this paper, on the basis of the physiological response of a subject, a comfortable algorithm of automobile air conditioner is being suggested.

• 한국응용과학기술학회지
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• 제34권4호
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• pp.962-973
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• 2017

대기오염에 대한 관심은 국내 외에서 점진적으로 상승하고 있으며, 자동차 및 연료 연구자들은 청정(친환경 대체연료) 연료와 연료품질 향상 등을 이용하여 새로운 엔진 설계, 혁신적인 후처리 시스템 등의 연구를 통하여 차량 배기가스 및 온실가스를 감소시키고자 노력하고 있다. 이에 본 연구에서는 각기 다른 차량기술이 적용된 휘발유, 경유, LPG를 연료로 사용하는 7대의 차량을 대상으로 국내 외에서 법적시험모드로 사용되고 있는 도심모드, 고속모드, 급가 감속, 에어컨사용 및 겨울철 특성을 반영한 저온모드에서 온실가스의 배출특성을 확인하고자 하였다. 사용연료에 관계없이 대부분의 온실가스는 저온인 Cold FTP-75 모드에서 가장 안 좋은 결과가 나타나는 경향을 가지고 있다. 각 차량별 온실가스 증가 요인으로는 가솔린 차량인 A차량(2.0 MPI)과 B차량(2.4 GDI)에서는 최고속 및 급가 감속, 에어컨 사용, 저온 조건의 순인데 비해 E차량(1.6 T-GDI)은 에어컨 사용, 최고속 및 급가 감속, 저온 조건의 순이다. G차량(LPLi)은 에어컨 사용, 저온, 최고속 및 급가 감속 조건의 순으로 가솔린 차량과 다른 특성을 가지고 있다. 경유 차량에 있어서는 A차량(2.0 w/o DPF)과 B차량(2.2 w/ DPF)은 최고속 및 급가 감속, 에어컨 사용, 저온 조건의 순이었고, F차량(1.6 w/ DPF)은 저온, 에어컨 사용, 최고속 및 급가 감속 조건의 순으로 확인되었다. 따라서, 각 연료별로 배출가스 저감 기술을 다르게 적용하여야 효과적인 방법이라고 할 수 있겠다.

• 한국공작기계학회논문집
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• 제13권4호
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• pp.100-105
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• 2004

Fin-tube type(Fin-type) heat exchanger has been tested in order to replace the heat exchanger of parallel flow type(P.F -type) which is now widly used in automobile air conditioning system The following conclusions are drawn by the comparison of the characteristics of the heat exchangers. Evaporator and condenser capacities and COP(Coefficience of performance) were varied as with the compressor speed, outdoor air temperature and air flow rate changed, which much influenced on the characteristics of the air conditioning system Evaporator and condenser capacities were increased with increasing compressor speed and outdoor air temperature. Evaporator and condenser pressures of Fin-type were decreased by 7% and 5% respectively compared with those of P.F-type. The COP of Fin-type was decreased with increasing outdoor air temperature and compressor speed. The COP of P.F-type was decreased by 14% compared with that of Fin-type.

• 한국자동차공학회논문집
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• 제20권5호
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• pp.120-129
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• 2012

As the recent advancement of automobile industry, there has been a great interest in the thermal comfort of the passengers inside the cabin of an automobile. Thermal comfort is affected by temperature, velocities, and mean radiation temperature of air, thermal resistance of clothes and physical active level of human. The present study performed computational analysis to select the location of air-conditioning vent that improves thermal comfort inside the cabin. In order to do this, we considered various air vent positions, and thermal flow analysis of each case is performed using CFD for the cabin with four passengers. The thermal comfort is evaluated using the computational results and the optimum location of air vent is suggested.

• 대한기계학회논문집B
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• 제39권9호
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• pp.713-718
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• 2015

본 연구의 목적은 자동차용 에어컨 시스템의 연비 개선을 위하여 압축기의 성능 향상을 도모하고자 하는데 있다. 압축기 성능은 자동차용 에어컨 압축기 전용 열량계를 이용하여 평가를 수행하였다. 압축기의 성능을 향상시키기 위하여 흡입 유량의 증대와 토출 사체적 축소를 검토하였으며, 각 개선 항목에 대한 평가를 진행하여 성능과 COP 의 개선을 확인하였다. 흡입 유량을 증대했을 경우 저속 구간보다 고속구간에서의 성능 효과가 컸으며, 토출 사체적을 축소했을 경우 상대적으로 저속 구간의 성능 개선효과가 컸다. 조합품의 경우 저속과 고속에서 전반적으로 균형 있게 개선되었으며, 토출측 온도가 가장 크게 개선되었다. 성능의 경우 저속에서 약 3.2%, 고속에서 약 8.3% 개선되었으며, COP 는 저속에서 약 5.8%, 고속에서 약 6.2% 개선되었고, 토출 온도는 저속에서 $3^{\circ}C$, 고속에서 $5^{\circ}C$ 개선되었다.

• 한국산학기술학회논문지
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• 제16권6호
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• pp.3708-3713
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• 2015

본 연구의 목적은 연료전지 자동차의 스택 시스템의 열적 특성을 파악하기 위하여 상용 수치 해석 프로그램을 이용하여 열전달 성능을 해석적으로 고찰하였다. 이를 위하여 연료전지 자동차가 일반도로 및 등판도로 등 주행 특성에 따른 스택 열관리 시스템의 냉각 특성과 에어컨의 작동 여부 등 운전 특성에 따른 스택 열관리 시스템의 냉각 특성을 고찰하였다. 스택 라디에이터로 유입되는 공기 유속이 증가함에 따라 모든 냉각수 유량조건에서 열전달 성능은 향상되었다. 공기 유속이 2 m/s에서 10 m/s로 증가함에 따라 스택 라디에이터의 열전달 성능은 냉각수 유량 20 l/min에서 105.3% 증가하였고, 냉각수 유량 120 l/min에서 221.3% 증가하였다. 스택 라디에이터는 가혹조건인 등판 각도 8% 및 속도 50 km/h에서 냉각수 입구 온도차 $9.45^{\circ}C$로 일반조건인 등판 각도 0% 및 속도 120 km/h에서 냉각수 입구 온도차인 $5.1^{\circ}C$보다 85.3% 증가했다. 또한, 연료전지 자동차가 가혹조건인 등판 주행시 에어컨 시스템을 작동할 경우 스택의 안정적 작동을 허용하는 한계 온도인 $70^{\circ}C$를 초과할 수 있다.

• 한국자동차공학회논문집
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• 제10권4호
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• pp.223-233
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• 2002

The air distribution duct with multiple outlets is an essential part of automotive air-conditioning system In a bus. The estimation of airflow rate in an automotive air-conditioning duct is typically very complicate due to large variations in cross-sectional area and abrupt changes in flow direction, as well as unbalanced distribution of the flow. In this paper, the flow characteristic in a duct with multiple outlets is investigated through experiment, CFD simulation and a one-dimensional simulation. Numerical simulations have been performed for two simplified air conditioning ducts with multiple outlets used in a medium bus. The three dimensional Navier-Stokes code was used to evaluate the overall pressure, velocity Held, and distribution rate at each diffuser according to the change of various design parameters such as ratio of cross-sectional area and radius of bifurcated region. In addition, a one-dimensional program based on Bernoulli equation was developed to obtain optimized diffuser area required to equalize discharge flow rate at each outlet. As a result of this study, optimized diffuser area of design variable by one-dimensional program was very reasonable as compared to the trend deduced from CFD Simulation. Therefore, the simple and convenient one-dimensional analysis developed in this study can be applied in practical design procedure for air-conditioning duct.

• 한국자동차공학회논문집
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• 제10권5호
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• pp.98-106
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• 2002

The airflow characteristics of an air-conditioning duct with multiple diffusers were investigated through one-dimensional analysis, CFD simulation and experimental measurement. One-dimensional program based on Bernoulli's equation and minor loss equations was developed in order to evaluate the air distribution rate at each diffuser. In CFD simulation, three-dimensional flow characteristics inside air-conditioning duct were computed for incompressible viscous flow, adopting the RNG k-$\xi$turbulence model. Also, in an effort to equalize the discharge flow rate at each outlet, the optimization procedure has been performed to obtain the optimum diffuser area. In this process, square of difference between maximum discharge rate and minimum discharge rate is used as an object function. Diffuser area and discharge velocity are established as constraints. After optimization process, determined design variables are applied again in CFD simulation and experiment to validate the optimized result by one-dimensional program. Comparison with the experimental data of airflow rate distribution showed that the developed program seems to be acceptable and can be useful design tool for an automotive air-conditioning duct in an initial design stage.

• 한국자동차공학회논문집
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• 제5권6호
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• pp.128-140
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• 1997

A new super compact condenser(SCC), which has been developed recently is especially suitable for an alternative refrigerant HFC-134a due to its high performance and compactness. The SCC is composed of two pipe headers, baffles, narrow multi-rectangular channels, and louvered fin arrays. Alternating inlet and outlet by the inserted baffles in pipe headers guide refrigerant to and from the narrow multi-rectangular channels. Since the flow rate and its lengh are changed depending on the number and location of baffles, the corresponding pressure drop and heat transfer rate are changed. The present study aims to theoretically and experimentally investigate the effects of baffle location and its number on the pressure drop and thermal performance of the SCC with 40 multi-rectangular channels. The results show that the present method provides an acceptable prediction of pressure drop and heat transfer rate for a 4 pass SCC. However, the model significantly under predicts the performance of a 3 pass SCC, which may be attributed to the phase separation of refrigerant flowing through header pipes. Pressure drop is more signifi- cantly influenced than heat transfer rate by the baffle location.