• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.205-208
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• 2007

We aim to develop antifreezing coolant used to in the 200kW Fuel Cell system that is possible to starting at low temperature and that must not to be freezed under $-30^{\circ}C$, have high coductivity, excellent system protection ability and durability.

• Journal of the korean Society of Automotive Engineers
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• v.16 no.6
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• pp.1-8
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• 1994

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.4002-4006
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• 2014

The automotive exhaust gases generated by the vehicles containing carbon monoxide, hydrocarbons and lead, is a large concern because of their harm to human health or the living environment. To reduce exhaust gas, it is important to develop a variety of techniques that are currently being used by elemental analysis to determine the optimal conditions. In this study, the anti-freeze coolant contained in the exhaust gas was examined, which can affect the emissions. The effects of the commercially available coolant from five domestic companies on the HC, NOx and $CO_2$ emissions were analyzed to determine the optimal amount of antifreeze. In addition, antifreeze products from the five companies were analyzed with respect to driving time of the cooling fan and the correlation of the NOx emission analysis. The temperature of the engine oil was matched using a manual gear of small passenger inspection standard speed $40{\pm}2Km/h$ so the vehicle could meet the specifications for inspection $90{\sim}93^{\circ}C$. The Company D fan operation time resulted in the shortest antifreeze, $CO_2$ and NOx emissions.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1027-1031
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• 2014

Free cooling system is used to reduce energy consumption of cooling system. Free cooling system is consisted of cooling group and dry-cooler in which heat exchange of chilled water and out air is conducted. Although this system has an excellent energy saving effect in place having cooling load regularly, data or material of design for free cooling system is lacked. In this study, characteristics analysis of free cooling system is conducted through software HYSYS with changing some facts. The main result is following as : Dry-cooler capacity is influenced by out air temperature, required chilled water temperature and LMTD(Logarithmic Mean Temperature Difference) of heat exchanger. As out air temperature is more low, dry-cooler capacity become increased. in addition, as required chilled water temperature is more high and LMTD is more low, the out air temperature range is widened for using dry-cooler. If out air temperature is below $0^{\circ}C$, antifreeze need to be used because freeze and burst can be occurred. In case of South Korea, antifreeze of 34% of ethylene glycol concentration is proper. When compressor load of R22, R134a and R407C is compared, considering environmental regulation and energy consumption, R134a is best working fluid.

• Tribology and Lubricants
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• v.6 no.1
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• pp.17-23
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• 1990

자동차용 부동액은 전열에 의한 발생열을 제거하고 Engine을 냉각시키는 물질로서, 이의 종류는 Alcohol계를 비롯하여 Glycol계 및 Ethylene Glycol계가 있다. 우리나라의 자동차 수출도 해를 거듭하여 증가일로에 있고, 근간에 있어서는 정부로 부터도 동구권 개방정책이 함께 대두되어 자국의 자동차 수출은 물론, 이의 사용되는 부품도 다국적 수출 전망이 매우 밝아지고 있음을 비추어 볼때, 방식제의 변천도 시대적응에 대응해야 하므로 본 논고에서는 사용수가 다른 Coolant의 구성인자들을 비롯한 제목건에 대하여 간략하게 기술하여 보고자 한다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.6
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• pp.403-408
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• 2016

Lithium-ion batteries are commonly employed in hybrid electric vehicles (HEVs), and achieving high energy density in the battery has been one of the most critical issues in the automotive industry. Because liquid cooling containing antifreeze is important in automotive batteries to enable cold starts, an effective geometric configuration for high-cooling performance should be carefully investigated. Battery cooling with antifreeze has also been considered to realize successful cold starts. In this article, we theoretically investigate a specific property of an antifreeze cooling battery system, and we perform numerical modeling to satisfy the required thermal specifications. Because a typical battery system in HEVs consists of multiple stacked battery cells, the cooling performance is determined mainly by the special properties of antifreeze in the coolant passage, which dissipates heat generated from the battery cells. We propose that the required cooling performance can be realized by performing numerical simulations of different geometric configurations for battery cooling. Furthermore, we perform a theoretical analysis as a design guideline to optimize the cooling performance with minimum power consumption by the cooling pump.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.5
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• pp.368-376
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• 2005

Coolant rubber hoses for automobile radiators can be degraded and thus failed due to the influence of contacting stresses of air and coolant liquid under thermal and mechanical loadings. In this study, for EPDM(ethylene-propylene diene monomer) rubber conventionally used as a radiator hose material the aging behaviors of the skin part due to thermo-oxidative and electro-chemical stresses were nondestructively evaluated. Through the thermo-oxidative aging test, it was shown that the surface hardness IRHD(International Rubber Hardness Degrees) of the rubber increased with a considerable reduction of failure strain. On account of the penetration of coolant liquid into the skin part the weight of rubber specimens degraded by electro-chemical degradation(ECD) test increased, whereas their. failure strain and IRHD hardness decreased largely. The penetration of coolant liquid seemed to induce some changes in inner structure and micro hardness distribution of the rubbers. Consequently, EPDM rubbers degraded by thermo-oxidative aging and ECD could be characterized nondestructively by micro-hardness and chemical structure analysis methods.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.3
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• pp.130-137
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• 2011

Experimental investigations are conducted to figure out the feasibility of $Al_2O_3$ nanofluids as the alternative coolant for car engine. For the purpose, the thermal conductivities and viscosities of water/commercial coolant based $Al_2O_3$ nanofluids with 0.3, 1.0, 2.0 and 3.0 vol. % at temperatures ranging from $25^{\circ}C$ to $35^{\circ}C$ are measured. Thermal conductivities are measured using the transient hot-wire method and also viscosities are measured by Brookfield LVDV-III rheometer. Based on the results, it is shown that thermal conductivity of $Al_2O_3$ nanofluids with 3.0 vol. % is increased about 11% at $35^{\circ}C$ and the increment of viscosity approaches to 84% at shear rate of 600(1/s) and 80% at shear rate of 960(1/s) in the same temperature. with fundamental data for the thermal conductivity and viscosity of the nanofluids, the feasibility of $Al_2O_3$ nanofluids as the alternative coolant for car engine are discussed.

• Journal of ILASS-Korea
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• v.20 no.2
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• pp.65-69
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• 2015

In this study, the thermal performance of vehicle's cooling system is experimentally investigated using the water/coolant-based $Al_2O_3$ nanofluids as working fluids. For the purpose, the water/coolant-based $Al_2O_3$ nanofluids are prepared by twostep method with gum arabic. In order to obtain the well-suspended nanofluids, the agglomerated $Al_2O_3$ nanoparticles are precipitated using centrifugal force and the experiments are performed with supernatant of them. The thermal conductivity is measured by transient hot wire method and the thermal conductivity of nanofluids is enhanced up to 4.8% as compared to that of base fluids. Moreover, the cooling performance of water/coolant-based $Al_2O_3$ nanofluids is evaluated using vehicle's engine simulator under the constant RPM condition. The results show that the cooling performance of automobile engine increases up to 5.9% using prepared nanofluids. To investigate the effect of nanofluids on exhaust gas, the $NO_x$ emission is measured during the operation with respect to time and 10.3% of $NO_x$ emission is decreased. The experimental results imply that the water/coolant-based $Al_2O_3$ nanofluids might be used as a next-generation vehicles' coolant

• Journal of the Korean Electrochemical Society
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• v.10 no.1
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• pp.25-30
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• 2007

Proton exchange membrane fuel cell(PEMFC) performance could be affected by various factors such as cell temperature, total pressure, partial pressure of reactants and relative humidity. Hydrogen ion is combined with water to form hydronium ion [$H_3O^+$] and pass through membrane resulting electricity generation. Cooling system is needed to remove heat and other uses on large scale fuel cell. In case that collant conductivity is increased, fuel cell performance could be decreased because produced electricity could be leaked through coolant. In this study, triple distilled water(TDW) and antifreeze solution containing ethylene glycol was used to observe resistance change. Resistance of TDW was taken 28 days to reach preset value, and effect on fuel cell operation was not observed. Resistance of antifreeze solution was not reached to preset value up to 48 days, but performance failure occurred presumably caused by bipolar plate junction resulting stoppage resistance experiment. Generally PEMFC humidification is performed near-saturated operating conditions at various temperatures and pressures, but non-humidifying condition could be applied in small scale fuel cell to improve efficiency and reduce system cost. However, it was difficult to operate large scale fuel cell without humidifying, especially higher than $50{\sim}60^{\circ}C$. In case of small flux such as 0.78 L/min, temperature difference between inlet and outlet was occurred larger than other cases resulting performance decrease. Non-humidifying performance experiments were done at various cell temperature. When both of anode and cathode humidification were removed, cell performance was strongly depended on cell operating temperature.