• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.25-30
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• 2003

Several desiccant cooling systems have been developed in terms of cost and performance. In this study a fin-tube exchanger has been used for liquid desiccant dehumidification system. This dehumidifier has been designed to study the absorption characteristic of the aqueous triethylene glycol(TEG) solution which has the flow range from 20 to 50 LPM. The dehumidifier performance characteristic of working factor variables such as inlet solution flow rate, air flow rate, solution concentration, solution temperature, brine temperature, air temperature and inlet air relative humidity has been analyzed. The result of this experiment can provide useful data for hybrid air conditioning system.

• 설비공학논문집
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• 제14권10호
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• pp.781-785
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• 2002

The effects of different surfaces on dry and wet frosting test were experimentally investigated. The results of experiment were compared by the performance evaluation coefficient (PEC). Results showed that the air-side pressure drop of lacquer coated evaporator increased by 5% as compared to the plasma treated one. It was also found that the Plasma coated evaporator is lower than lacquer coated one in the PEC ratio.

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권2호
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• pp.271-276
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• 2017

The triple-gate tunnel FETs encapsulated with an epitaxial layer (EL TFETs) is proposed to lower the subthreshold swing of the TFETs. Furthermore, the band-to-band tunneling based on the maximum electric-field can occur thanks to the epitaxial layer wrapping the Si fin. The performance and mechanism of the EL TFETs are compared with the previously proposed TFET based on simulation.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2002년도 춘계 학술발표회 논문집
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• pp.21-27
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• 2002

Catalytic combustor with heat exchangers are often employed in process technology where a compact design is required [1]. The use of fin and tube heat exchanger offers the enhanced surface area for heat exchange. The recent progress and performance of the fin-tube heat exchanger, especially airside, has been reviewed extensively by Wang[2].(Omitted)

• 에너지공학
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• 제16권3호
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• pp.149-154
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• 2007

본 연구에서는 슬릿 휜-관 열교환기의 공기측 압력강하 특성을 실험적으로 고찰하였다. 물을 작동유체로 사용한 기존의 실험은 공기측 압력강하에 대해 일관된 방법을 제시하지 못하고 있다. 따라서 본 연구에서는 R22를 적용하여 휜-관 열교환기의 전표면과 습표면에 공기측의 압력강하 특성을 나타내는 표준 방법을 제시하고자 하였다. 기존의 실험 상관식과 본 연구에서 제시한 실험 데이터를 증발기와 응축기의 설계조건에서 레이놀즈수와 f-factor의 관계식으로 나타내었다. 본 실험은 공기의 속도가 $0.38{\sim}1.6\;m/s$ 일 때 냉매의 질량 유속 범위를 $150{\sim}250\;kg/m^2s$하여 수행하였다.

• 설비공학논문집
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• 제28권11호
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• pp.428-433
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• 2016

The fin and tube heat exchanger using a two-port tube has in air-conditioner heat exchanger because heat transfer performance. This study investigates the feasibility of a fin and tube heat exchanger using two-port copper tube by mechanical expansion. The optimum size of the tube-expanding bullet for the heat exchanger using two-port tube was through numerical calculation. The heat exchanger using a two-port tube was fabricated by mechanical expansion, and the heat exchanger performance was evaluated condensation and evaporation experiments. Compared to the heat exchanger of a conventional circular tube, the pressure drop per unit length of the heat exchanger with a two-port tube decreased. Compared to the heat exchanger using a conventional circular tube, the overall heat transfer coefficient of heat exchanger with a two-port tube increased up to 13% in the case of condensation, and up to 25% in the case of evaporation. The two-port tube heat exchanger outperforms conventional heat exchanger for air conditioner with a inner grooved circular tube.

• 대한기계학회논문집B
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• 제25권1호
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• pp.117-123
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• 2001

In present study a methodology has been developed and applied for the optimum design and performance evaluation of microchannel heat sinks. The optimum design parameters include channel number and fin thickness. For a trial model of 127mm in length, 52.5mm in width, 16mm in height and 2.5mm in base thickness, the optimum channel number and the fin thinckness have been determined to be of 194 and 0.08359mm, respectively in laminar flow region. Performance of the optimally designed microchannel heat sinks has been compared with those having 50% and 150% of the number of channels. The results showed that the 50% and 150% designs increased the pumping power by 200% and 150%, respectively.

• 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.

• 대한기계학회논문집B
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• 제34권5호
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• pp.531-537
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• 2010

본 연구에서는 옵셋 스트립 휜 열교환기에서 휜 형상에 대한 최적화를 수행하였다. 압력강하량은 감소시키고 열전달량을 증가시키기 위해 이 둘을 동시에 나타낼 수 있는 j/f, $j/f^{1/3}$, JF 등의 성능 인자가 고려되었다. STDQAO, PQRSM, MGA 등의 최적화 기법이 사용되었으며, MGA 를 통해 기존 옵셋 스트립 휜보다 JF 인자는 36%, 열전달 성능은 280% 향상된 최적화된 휜 형상을 제안하였다.

• 설비공학논문집
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• 제17권9호
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• pp.816-823
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• 2005

This paper deals with the heat exchange performance prediction of a counter flow type double-tube condenser for natural refrigerant mixtures composed of Propane/n-Butane or Propane/i-Butane in a smooth tube and a micro-fin tube. The local characteristics of heat transfer, mass transfer and pressure drop are calculated using a prediction method developed by the authors. The total pressure drop and the overall heat transfer coefficient are also evaluated on various heat exchange conditions. The calculated results of the natural refrigerant mixtures are compared with HCFC22. In conclusion, natural refrigerant mixtures composed of Propane/n-Butane or Propane/i-Butane are appropriate candidates for alternative refrigerant from the viewpoint of heat transfer characteristics.