• 설비공학논문집
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• 제26권1호
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• pp.48-54
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• 2014

A refrigeration dehumidifier with a recuperative heat exchanger is theoretically analyzed. The recuperative heat exchanger is located between the two air streams from and to the dehumidifying coil, and reduces the sensible heat load in dehumidification process. A simple model is developed to predict performance of the dehumidifier. The model predicts that the recuperative heat exchanger is effective especially in the low humidity condition, where the sensible heat load is relatively large. It is predicted that, by adopting a recuperative heat exchanger, a maximum 30~110% increase in COP is possible for indoor air at $27^{\circ}C$, and 40~60% relative humidity.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.25-30
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• 2000

Plate and shell heat exchanger(P&SHE) has been applied to the refrigeration and air conditioning systems as evaporators or condensers fur their high efficiency and compactness. The purpose of this study is to analyze the characteristics of pressure drop in plate and shell heat exchanger. An experiment for single phase (low pressure drop in plate and shell heat exchanger was performed. Also numerical work was conducted using the FLUENT code for $ {\kappa}-{\varepsilon}$ model. The dependence of friction factor on geometrical Parameters was numerically investigated. The study examines the internal flow and the pressure distribution in the channel of plate and shell heat exchanger. The results of CFD analysis compared with experimental data, and the difference of frictor factor in plate side and shell side are 10% and 12%, respectively. Therefore, the CFD analysis model is effectively predict the performance of plate and shell heat exchanger.

• 설비공학논문집
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• 제11권3호
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• pp.292-300
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• 1999

Fin conduction not only enhances heat transfer to the ambient air but also increases tube-to-tube conduction. The latter is known to deteriorate the heat exchanger performance. Heat conduction between neighboring tubes thorough the fin is numerically investigated for accurate performance analysis of plate finned-tube heat exchangers. Governing equations for arbitrary plate fin are solved and the temperature distribution is obtained using the principle of superposition. Analysis is made using finite element method by changing the shapes of fin, the arrangements of tubes and the fin parameter mD. It is found that tube-to-tube conduction is significant when mD is small or the distance between neighboring tubes is small.

• 설비공학논문집
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• 제9권1호
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• pp.73-81
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• 1997

In this experimental study, the air cooling radial shape heat exchanger which influences on the COP and the cooling capacity by heat and mass transfer rate in the adsorbent bed was designed and applied to test its performance for adsorption heat pump(AHP). Zeolite-water was used for the adsorbent-adsorbat pair. As a result, the cooling COP and a cycle period of this adsorption heat pump are 0.28 and 2 hours, respectively, on the condition of none heat recovery from the adsorption reactor(absorber). The other results and recommendations are mainly related to improving the heat and mass transfer inside the absorber to reduce a cycle period.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2363-2368
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• 2008

The objectives of this paper are to measure the heat transfer and pressure drop of the plate heat exchangers for absorption system applications. Three types of plate heat exchangers with different chevron angles are tested in the present experiment. Heat transfer and pressure drop performance of plate heat exchangers are measured in various operating conditions, and compared each other. The results show that the heat transfer rate of high theta ($120^{\circ}$) and mixed theta plate heat exchanger increases about 118% and 98% at the solution flow rate 350 kg/h compared to that of low theta ($60^{\circ}$), respectively. The effectiveness of high theta was evaluated about $0.70{\sim}0.83$ in this experimental range.

• 설비공학논문집
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• 제24권1호
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• pp.45-50
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• 2012

The plate fin and tube type of heat exchanger is widely used in air conditioner, and the heat exchanger is assembled by the mechanical expansion of copper tubes and fastening the aluminum fin. The objective of the present study is to investigate how the mechanical expansion of copper tube affects on the heat transfer performance of a plate fin and tube type heat exchanger. This study has been performed by experimental and numerical methods. The numerical and experimental results show that the tube expansion ratio has a influence on the heat transfer performance. Within the tested expansion ratio, the contact pressure shows the peak value and it decreases as the expansion ratio increases. Air-side heat transfer coefficient increases until the expansion ratio reaches 1.23, and then decreases with the similar pattern to the contact pressure. Also, contact heat transfer coefficient shows the maximum when the contact pressure is highest as well as the air-side heat transfer coefficient.

• 한국지열·수열에너지학회논문집
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• 제14권1호
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• pp.22-29
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• 2018

The purpose of this study is to investigate the preliminary thermal performance of a plastic coated aluminum material(PCAM) plate heat exchanger. Plastic coating which has high corrosion resistivity and thermal conductivity can overcome corrosive weakness of aluminum material. The heat exchangers are modeled for STS316, Titanium and PCAM materials, and analyzed numerically using HTRI and ANSYS Fluent CFD softwares. The results show that PCAM heat exchanger is superior in heat transfer performance compared to existing materials. For chevron angle of $60^{\circ}$, thermal performances of Titanium and PCAM are higher by 12.2% and 48.9% when compared to STS316, respectively.

• 설비공학논문집
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• 제20권11호
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• pp.767-774
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• 2008

This paper presented the heat transfer and pressure drop characteristics for micro plate heat exchanger with straight channel. The metal sheets for straight channel are manufactured by chemical etching and fabricated micro plate heat exchangers by using the vacuum brazing of bonding technology. The performance experiments are performed within the Reynolds numbers range of 15$\sim$250 under the same flow rate conditions for hot and cold sides. The inlet temperature of hot and cold water are conducted in the range of $30^{\circ}C{\sim}50^{\circ}C$ and $15^{\circ}C{\sim}25^{\circ}C$, respectively. Heat transfer rate and pressure drop are evaluated by the Reynolds numbers and mass flow rates as the inlet temperature variations of the hot and cold sides. Correlations of Nusselt number and friction factor are suggested for micro plate heat exchanger with straight channel using the results of performance experiment.

• 설비공학논문집
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• 제16권6호
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• pp.584-588
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• 2004

This work was performed to investigate the heat transfer characteristics of the circular fin-tube heat exchanger. This paper contains the experimental data for the seven kinds of fin geometries. The correlation of Stasiulevicius agreed with the experimental data at high Reynolds number, however not well at low Reynolds number. The Nusselt number was well correlated with Graetz number, and showed a transition near Gz=10. An empirical correlation proposed in the present work agreed well with the experimental data.

• 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)