• Progress in Superconductivity and Cryogenics
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• v.12 no.4
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• pp.1-7
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• 2010

The pulse tube cooler as an alternative of Stirling, G-M or VM cooler to overcome the requirement from the various application fields is described. The necessity of the object oriented cooler development is explained to realize the cryocooler of more energy-efficient, more reliable, more compact and less expensive than what is currently available commercially.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.9
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• pp.1615-1620
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• 2010

A thin film thermoelectric cooler for COB direct assembly was proposed and the COB cooler structure was modeled by electrical equivalent circuit by using SPICE model of thermoelectric devices. The embedded cooler attached between the die chip and metal plate can offer the possibility of thin film active cooling for the COB direct assembly. We proposed a driving method of TEC by using pulse width modulation technique. The optimum power to the TEC is simulated by using a SPICE model of thermoelectric device and passive components representing thermal resistance and capacitance. The measured and simulated results offer the possibility of thin film active cooling for the COB direct assembly.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.4
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• pp.87-94
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• 2004

Recently, technical trend in machine tools is focused on enhancing of speed, accuracy and reliability. The high speed usually results in thermal displacement and structural deformation. To minimize the thermal effect, precision machine tools adopt a high precision cooling system. This study proposes a temperature control for an oil cooler system using Pill control with fuzzy logic. In the cooler system, refrigerant flow rate is controlled by rotational speed of a compressor, and outlet oil temperature is selected as the control variable. The fuzzy control rules iteratively correct PID parameters to minimize the error and difference between the outlet temperature and the reference temperature. Here, ambient temperature is used as the reference one. To show the effectiveness of the proposed method, a series of experiments are conducted for an oil cooler system of machine tools, and the results are compared with the ones of a conventional Pill control. The experimental results show that the proposed method has advantages of faster response and smaller overshoot.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.5
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• pp.112-117
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• 2007

With the Euro-4 regulation coming into effect, the domestic car industry is forced to look for newer options to reduce NOX in the exhaust. EGR(Exhaust Gas Recirculation) Cooler is an effective method for the reduction of NOX form a diesel engine. High efficiency, low pressure loss and compactness are desirable features of an EGR Cooler. The cooling performance of EGR depends on the shape of tubes and the location of the entrance and exit. This paper reports the computational work conducted to estimate the performance of EGR cooler with three different cross section tubes and a triangular spiral tube. Three dimensional computation results show that the triangular tube is more effective than circular and rectangular tube. The most effective geometry is a triangular spiral tube with offset inlet and outlet locations.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.147-148
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• 2012

The syngas produced from coal gasification is cooled down for gas cleaning by a syngas cooler that produces steam. Due to the presence of fly slag in the syngas, erosion, slagging and corrosion especially in the upper part of the syngas cooler may cause major operational problems. This study investigates the flow, heat transfer and particle behaviors in the syngas cooler of a 300MWe IGCC plant by using computational fluid dynamics. For various operational loads and geometry, the gas and particle flows directly impinged on the wall opposite to the syngas inlet, which may lead to erosion of the membrane wall. In the evaporate channels inside the syngas cololr, the particle flows were concentrated more on the outer channel where slagging becomes more serious. The heat transfer to the wall was mainly by convection which was larger on the side wall below the inlet level.

• Journal of Advanced Marine Engineering and Technology
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• v.16 no.4
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• pp.78-87
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• 1992

The experimental study and theoretical analysis are made in order to investigate a new refrigeration system, R-22 and R-502 or R-13 cascade compressor with panel type cooler, for tuna long liner. The experimental apparatus consists with the cascade unit, 1.5 HP R-502 compressor in the first stage and 1 HP R-22 compressor in the second stage, and 3 $m^2$ cold storage room with a direct expansion panel type cooler. The main result are as follows: 1. The energy saving and C.O.P. of the R-22 and R-502 or R-22 and R-13 cascade are improved much higher than two stage compressor. 2. For the point of simplicity of design, installation, and running cost, the panel type cooler is much better than traditional hair pin coil type cooler. 3. From the experimental data and analysis, the R-22 and R-502, or R-22 and R-13 cascade compressor with panel type cooler is recommended for a new refrigeration equipment of the tuna long liner.

• Journal of Power System Engineering
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• v.18 no.5
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• pp.150-155
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• 2014

This paper presents The performance analysis of inverter control type-industrial cooler with respect to refrigeration load and outdoor temperature. Aside from materials about simulations and foundation data regarding inverter control compressors, currently, data about commercial coolers with inverter control still lack information for performance comparison. Thus, in this paper, the experiments are done to see characteristics of condensation capacity, evaporation capacity, compressor power and COP with respect to outdoor temperature and load by using a commercial inverter control cooler model. As a result, COP difference of the inverter control cooler with respect to load is 30% at the outdoor temperature of $35^{\circ}C$, 29% at the outdoor temperature of $30^{\circ}C$, 34% at $25^{\circ}C$, respectively.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.197-202
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• 2007

In this study, the cooling characteristics of a liquid cooler using thermoelectric module was experimentally investigated. The experiment was conducted for various inner structures of liquid cooler (4 cases), hot fluid flow rates (0.15-0.25 L/min), number of T.E module (2, 4, 6 set), and the cooling water flow rates (200-600 cc/min) for both parallel and counter flow types. Among the results, better cooling performance geometry was selected. And experiment was also carried out to examine further enhancement of cooling performance by inserting coils (pitches: 0.2, 3, 6 mm) into the hot-fluid channel. Present results showed that the short serpentine type(case2) indicated the best cooling performance. In the case of coil pitch of 3 mm, the best cooling performance was shown, more than 10% increase of the inlet and outlet temperature difference, compared with the case of the cooler without coil. Consequently, the inserted coil pitch should be properly selected to improve cooling performance.

• Journal of Power System Engineering
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• v.9 no.3
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• pp.5-9
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• 2005

A study on the performance and exhaust emissions of diesel engine with reducing exhaust gas temperature is performed experimentally. In this paper, experiments are performed at engine speed 2200rpm, 2600rpm and load 0%, 25%, 50%, 75% and 100% by test engine with F.W. cooler passing through exhaust gas. Main measured & analyzed parameters are exhaust gas temperature, specific fuel consumption, NOx and soot emissions etc. The obtained conclusions are as follows. (1) Specific fuel consumption is the least value at load 75% and it is decreased 1.5% after remodeling F.W. cooler. (2) NOx emission is the most value at load 100% and it is increased 30.1% after remodeling F.W. cooler. (3) Soot emission is the most value at load 100% and it is decreased 20.0% after remodeling F.W. cooler.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.483-488
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• 2006

In this study, newly-developed slim electronic panel cooler with aluminum PF condenser and evaporator was tested and the results are compared with imported panel cooler with fin-tube heat exchangers. The PF heat exchangers significantly (approximately 45%) reduced the refrigerant charge. The air-side pressure drop was also reduced, which resulted in the reduction of the sound level of the panel cooler. The effect of the condenser size was also investigated.