• 설비공학논문집
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• 제29권6호
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• pp.279-288
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• 2017

Heat generation rate in a telecommunication cabinet increases due to the continued usage of mobile devices. Insufficient removal of heat intensifies the cabinet temperature, resulting in the malfunction of electronic devices. In this study, we assessed both aluminum and plastic heat exchangers used for cooling of the telecommunication cabinet, and compared the results against theoretical predictions. The aluminum heat exchanger was composed of counter flow parallel channels of 4.5 mm pitch, and the plastic heat exchangers were composed of cross flow triangular channels of 2.0 mm pitch. Samples were made by installing two plastic heat exchangers in both series and parallel. Results showed that the heat transfer rate was highest for the series cross flow heat exchanger, and was least for the aluminum heat exchanger. The temperature efficiency of the series cross flow heat exchanger was 59% greater than that of the aluminum heat exchanger, and was 4.3% greater than that of the parallel cross flow heat exchanger. In contrast, the pressure drop of the parallel cross flow heat exchanger was significantly lower than other samples. The heat exchange efficiency was also the largest for the parallel cross flow heat exchanger. The theoretical analysis predicted the temperature efficiency to be within 3.3%, and the pressure drop within 6.1%.

• 설비공학논문집
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• 제17권2호
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• pp.117-124
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• 2005

Aluminum plate heat exchanger, rotary wheel heat exchanger, and heat pipe heat exchanger have been used (or ventilation heat recovery in the air-conditioning system. The purpose of this research is to develop high efficiency plastic plate heat exchanger which can substitute aluminum plate heat exchanger. Because thermal conductivity of plastic is quite small compared to that of aluminum, various heat transfer enhancement techniques are applied in the design of plastic plates. Five types of heat exchanger model are designed and manufactured, which are plate type, plate-fin type, turbulent promoter type, corrugate type, and dimple type. Thermal performance and pressure loss of each heat exchangers are measured in various operating conditions, and compared each other. Test results show that heat transfer performance of corrugate type, turbulent promoter type, and dimple type are increases about $43\%$, $14\%$, and $33\%$ at the equivalent fan power compared to those of plate type, respectively. On the other hand, the heat transfer performance of plate-fin type decreases $9\%$ because fins can not play their own role.

• 설비공학논문집
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• 제17권9호
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• pp.839-848
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• 2005

Plastic plate heat exchangers have many advantages over the conventional heat exchangers such as aluminum plate heat exchangers, rotary wheel heat exchangers and heat pipe heat exchangers which have been used for ventilation heat recovery in the air-conditioning systems. In the present study, pressure drop and heat transfer characteristics of plastic plate heat exchangers are investigated for various design parameters and operating conditions which affect the performance of the plastic plate heat exchangers. In flat plate type heat exchanger, material thickness and channel height of heat exchanger are considered, and corrugate size and heat transfer area are considered in case of corrugate type heat exchanger. Pressure drop and effectiveness of the corrugate type heat exchanger increase as the corrugate size decreases.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.328-333
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• 2008

In order to control indoor air quality and save energy, it is needed to install a suitable heat exchanger for heat recovery. A plastic heat exchanger have many advantages and can recover $50{\sim}80%$ of the temperature difference between supply and exhaust air. The purpose of this research is to evaluate the performance of plastic heat exchanger with different shapes. Pressure drop and heat transfer characteristics of plastic heat exchangers are investigated for various velocities.

• Journal of Advanced Marine Engineering and Technology
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• 제29권4호
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• pp.407-416
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• 2005

The kimchi refrigerator is the electric home appliance which is used for the maturing and preserving of the kimchi in domestic and foreign market. The kimchi refrigerator is composed in 3 main parts as insulation. kimchi container, machinery room. The heat exchanger of kimchi refrigerator is made of aluminum and the other parts are made of steel and polymer. Also, kimchi refrigerator is expensive and heavy as compared with same class of refrigerator until now. In the present study, the possibility to replace heat exchanger from aluminum to thermal conductive plastic was analyzed and experimented. The thermal conductive plastic has $10{\sim}100$ times heat conductivity than that of normal plastic. It is known that heat transfer process is dependent not only conduction but convection or radiation. Thermal conductivity of the applied material in this research is over than 2 W/mK, thermal conductivity doesn't play a vital role on heat transfer. In this study, temperature is the most important parameter on the kimchi refrigerator and the temperature of kimchi refrigerator's heat exchanger was measured and compared with the temperature calibrated by CFD analysis on the inside wall of the kimchi refrigerator. It is important to keep constantly the inside temperature of the Kimchi refrigerator. Besides numerical analyses for the new thermal conductive plastic for heat exchanger were executed with the various height of evaporation tube. A series of experiments were conducted to compare the performance of the two heat exchanger made of aluminum and thermal conductive plastic at the same condition and certified the possibility of the thermal conductive plastic. According to these results, it was confirmed that the conventional aluminium heat exchanger can be replaced by thermal conductive plastic successfully.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1366-1371
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• 2008

Four simulation models of plastic plate heat exchangers are designed and simulated. The flat plate type heat exchanger is designed as the reference model in order to evaluate how much thermal performance increases. The turbulence promoter type heat exchanger is fabricated with cylindrical-type vortex generators and rib-type turbulence promoters. The corrugate type is obtained from the conventional stainless steel compact heat exchangers, which are called the herringbone-type compact heat exchangers. The dimple type heat exchanger has a number of dimples on its surface. In this study, the flow and heat transfer characteristics of the plastic plate heat exchanger are investigated using numerical simulation and compared with experimental results. The flows are assumed as a three-dimensional, incompressible and turbulent model. The standard k-$\varepsilon$ model is used as the turbulent flow modeling, the SIMPLE algorithm is used to treat the coupling between pressure and velocity, and first order upwind scheme is used for discretization of momentum, turbulent and energy. The computational analysis and experimental results both show that the friction coefficient and Nu number is highest in the corrugate type.

• International Journal of Air-Conditioning and Refrigeration
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• 제17권2호
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• pp.52-60
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• 2009

The purpose of this research is to develop high efficiency plastic plate heat exchangers which can be substituted for conventional aluminum plate heat exchangers. Four simulation models of plastic plate heat exchangers are designed and simulated: that is, flat plate type, turbulent promoter type, corrugate type and dimple type heat exchanger. The flat plate type is designed as the reference model in order to evaluate how much thermal performance increases. The turbulent promoter type is fabricated with cylindrical-type vortex generators and rib-type turbulent promoters. The corrugate type is obtained from the conventional stainless steel compact heat exchangers, which are called the herringbone-type compact heat exchangers. The dimple type has a number of dimples on its surface. In this study, the flow and heat transfer characteristics of the plastic plate heat exchanger are investigated using numerical simulation and compared with experimental results. Numerical simulation is carried out using the FLUENT code. The flows are assumed as a three-dimensional, incompressible and turbulent model. The computational analysis and experimental results both show that the friction coefficient and Nu number is highest in the corrugate type. The tendency of numerical simulation results is in good agreement with that of the experimental results.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.115-118
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• 2002

The present study deals with CFD analysis of a plastic heat exchanger with corrugated wall. This exchanger has sinusoidal corrugations, and the flow through the exchanger is three dimensional. In addition, CFX-5.4, a commercial code utilizing unstructured mesh, was used as a computational method for solving RANS(Reynolds-Averaged Navier-Stokes) equations, and the applied turbulence model is $k-{\varepsilon}$ model. The factors to affect the efficiency of a plastic heat exchanger are heat conductivity, flow characteristics and so on. For those two factors, heat conductivity is fixed by the wall material. Therefore, the How along the corrugation affects the efficiency more, provided the same material. In conclusion, the heat transfer enhancement of a plastic heat exchanger with corrugated wall can be recognized from the flow characteristics such as velocity streamline, local heat transfer coefficient, velocity contour, and pressure contour. To confirm the results, both of the measured and the computational data for pressure loss were compared with each other, and they were identical.

• 한국산학기술학회논문지
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• 제18권1호
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• pp.702-708
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• 2017

함체 내의 발열은 이동통신기기의 회선 처리 능력이 증가함에 따라 계속 증가하고 있다. 이 열을 적절히 외부로 방출해 주지 않으면 중계기 내의 온도가 상승하여 전자장치 오작동의 원인이 된다. 본 연구에서는 통신 함체 냉각 모듈용 알루미늄 및 플라스틱 소자의 성능에 대해 실험을 수행하고 이론 해석 결과와도 비교하였다. 알루미늄 소자는 핏치 4.5 mm의 대향류 평행 채널로 구성되고 플라스틱 소자는 핏치 2.0 mm의 직교류 및 직교 대향류 삼각 채널로 구성되었다. 한편 직교류 소자의 크기는 알루미늄 소자와 동일하고 직교대향류 소자는 알루미늄 소자보다 33% 크다. 실험 결과 플라스틱 직교 대향류 소자의 전열량이 가장 크고 알루미늄 대향류 소자의 전열량이 가장 작게 나타났다. 또한 알루미늄 대향류 소자를 base 소자로 할 때 플라스틱 직교대향류 소자의 온도교환효율은 base 소자보다 평균 56% 크고 플라스틱 직교류 소자의 값보다는 평균 29% 크게 나타났다. 한편 플라스틱 직교대향류 소자와 base 소자의 압력손실은 유사하게 나타났다. 열교환 효율은 플라스틱 직교대향류 소자에서 가장 크고 플라스틱 직교류 소자에서 가장 작게 나타났다. 또한 이론 모델은 소자의 성능을 다소 과대 또는 과소 예측하였다.

• 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.