• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.5
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• pp.113-119
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• 2015

The technical development of electric vehicles has been actively proceeding because of the reduction of oil resources and need for eco-friendly vehicle technology. In particular, an electronic control unit is an important element in the technology of electric vehicles due to the motor drive system. This paper concerns an experimental study on the thermal analysis of the steering control ECU structure for an electric vehicle. The ECU unit is designed for eight heat sinks for the thermal analysis of the ECU structure. The thermal analysis characteristics of the ECU structure are evaluated by the temperature distribution, heat flow, von Mises stress, total translation, and external surface temperature measurement of the ECU unit.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.10
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• pp.537-543
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• 2015

Air-source heat pumps are widely used in winter as heating units due to their higher efficiency compared to electronic heaters or gas fired equipment. However, the air-source heat pump can cause discomfort during periodic defrosting operations. In this study, a PCM unit for continuous heating was adopted to solve this problem. The PCM unit consisted of a PCM, a heat exchanger, and control valves. It was installed between the outdoor and indoor units. The performance of the proposed system was measured during both defrosting and heating operations. The indoor unit showed an average leaving temperature of $26^{\circ}C$ after adopting the PCM unit for continuous heating during the defrosting operation.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.6
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• pp.1237-1243
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• 2001

This paper presents an information about the heat transfer characteristics of impinging jet in eletronic equipment with infrared image processing unit. There have been many experimental investigations and theoretical studies on impinging jet because of application in a wide variety of industrial process including electronic equipment. In this study, we used infrared image processing unit to visualize heat transfer characteristics of impinging jet in eletronic equipment. Infrared image processing unit is one of non-contact temperature measuring methods and it is possible to minimize flow resistance and this measurement is comparatively accurate. The main parameters are distance between nozz1e and heat source. Reynolds number is 6000.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.422-429
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• 2008

The objective of the present study is to develope a propultion unit cooling system for the next-generation High-speed EMU. The propulsion power control unit consists of some IGBT semiconductors. In general, those power semiconductors are very sensitive to temperatures and need a cooling system to keep them at a proper operational conditions in the range of $50{\sim}100^{\circ}C$. In this first year of study, we tried to focuss on the understanding of fundamental technologies for each of the two different cooling systems and collecting basic data for design and manufacturing for both cases. For the water cooling system, a heat sink with multi channels of liquid flow was considered and a model unit was designed and performance test was conducted. For the heat pipe cooling system, a Loop Heat Pipe(LHP) was considered as an element to transport heat from IGBT to environment air flow and a model unit was designed and performance test was conducted. The analysis using SINDA/FLUINT showed that those design parameters are good enough for the LHP to properly operate under a heat load up to around 360W.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2004.05a
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• pp.197-200
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• 2004

Compared to conventional flame combustion, catalytic combustion had the advantage of oxidation of V.O.C. gas which was high voluminous, low caloric mixture flow. However, the temperature of mixture gas should be over the one of catalytic reaction start and the control of reaction on the catalytic surface tends to be vulnerable. To overcome these obstacles, composition of both catalytic combustor and heat exchanger was devised and named the sequential catalytic combustion system. In this system, only trigger unit needed preheating process for transient starting time. Once trigger unit was ignited, the next unit w3s supplied heat to ignite from that and same process was performed to the last one sequentially. When it come to steady state, whole mixture gas was oxidated at each unit simultaneously and preheating for trigger unit was not needed any more. System of 100 kcalh/hr capacity was devised and operated successfully.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.1937-1941
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• 2007

During a process of a nanoimprint for manufacturing LCD, a small temperature variation on the LCD glass can cause thermal stress and generate unexpected displacement. To avoid this trouble, a precision temperature control unit using thermoelectric modules is appropriate for nanoimprint processes. The unit consists of an air control system, a cooling water control system, and a power control system. The air control system includes a thermoelectric module, thermocouples measuring temperatures of air and a duct-stale fin, and two air fans. The heat generated by the thermoelectric module is absorbed by the cooling water control system. The power control system catches the temperature of the thermoelectric module, and a PID controller with SCR controls the input power of the thermoelectric module. Temperature control performance is evaluated by experiment and simulation. The temperature control unit is able to control the exit temperature about ${\pm}2^{\circ}C$ from the incoming fluid temperature, and the error range is ${\pm}0.1^{\circ}C$. However, the control time is approximately 30minute, which needs further study of active control

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.5
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• pp.446-475
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• 2000

Performance of a water-to-water multi-type heat pump system using R22 has been experimentally investigated. Total refrigerant flow rate was adjusted with a variable speed compressor and the refrigerant flow rate for two indoor units were controlled by electronic expansion valves. Evaporator outlet pressure of refrigerant and indoor unit outlet temperatures of secondary fluid were selected as controlled variables. Experiments were carried out for both cooling and heating modes using PID control method. Results show that the multi-type heat pump system can be adequately controlled by keeping control gains at certain levels for various operating conditions.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.9
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• pp.810-817
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• 2001

Performance of a water-to-water multi-type heat pump system using R22 which has tow indoor units has been investigated experimentally. The refrigerant flow rate of each indoor unit was regulated by an electronic expansion valve and the total refrigerant flow rate of the system was controlled by a variable speed compressor. In the system, evaporator outlet pressure of refrigerant and outlet temperatures of secondary fluid from indoor units were selected as control variables. Experiments were executed for both cooling and heating modes using PID control method with fuzzy logic, and results of the test are compared with a classical PID method. In the case of PID control with fuzzy logic, the fuzzy control rules corrects PID parameters each time. Results show that PID control with fuzzy logic has the merits of quick response and reduced overshoot.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.643-649
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• 2008

The purpose of this study is to establish a standard for unit cooling load in central control type apartment applied district cooling. The model of unit household was selected. And the standard of coefficient of overall heat transmission, location of unit household, indoor air temperature, solar radiation & thermal conduction at window and interior load was selected, and region, expansion or non-expansion of balcony, pyeong type, azimuth, rate of window area was applied as parameter. And then cooling load simulation was performed. Based on the result of simulation, the synthetic district cooling load was presented for selecting heat source of apartment applied district cooling, and unit cooling load was analyzed according to design parameter.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.1
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• pp.28-34
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• 1999

According to the development of tool material and the improvement of machinability of cutting material like aluminium alloy, the higher spindle speed is needed. However, the higher speed causes the heat generation of bearings, the deformation of spindle unit parts, and the rotational accuracy of spindle to be worse. Therefore, it is essential to analyze and control the heat generation and the thermal behavior of spindle unit in order to have higher speed and better rotational accuracy. This paper shows the analogy between the analyzation of heat generation and thermal behavior of high speed spindle system by finite element method and the test results of actual temperature rise through running test, and shows the necessity of cooling the spindle and inner ring side of bearings for the thermal balance of high speed spindle system.