• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.37 no.1
• /
• pp.35-41
• /
• 2013

In injection molding, the mold temperature is one of most important process parameters that affect the flow characteristics and part deformation. The mold temperature usually varies periodically owing to the effects of the hot polymer melt and the cold coolant as the molding cycle repeats. In this study, a pulsed mold temperature control was proposed to improve the part quality as well as the productivity by alternatively circulating hot water and cold water before and after the molding stage, respectively. Transient thermal-fluid coupled analyses were performed to investigate the heat transfer characteristics of the proposed pulsed mold heating and cooling system. The simulation results were then compared with those of the conventional mold cooling system in terms of the heating and cooling efficiencies of the proposed pulsed mold temperature control system.

• 전자공학회논문지 IE
• /
• v.49 no.2
• /
• pp.40-45
• /
• 2012

In this paper, cooling system of power transformers is proposed for temperature optimized control. We predict the peak temperature of power transformer coils using load factors and construct a cooling system using weighting function. For the optimized temperature control for power transformer, a correlation function based on the load factor of a load current and the each temperatures for winding coils, for air and for oil is presented to predict the winding-coil peak temperature. Also, the results controlled by applying the power transformer is presented.

• Food Science and Preservation
• /
• v.11 no.2
• /
• pp.263-268
• /
• 2004

Two field cooling tests were conducted to evaluate the cooling characteristic of paddy with a prototype grain cooler. The first test was carried out during summer season in a steel bin with 180.3ton of paddy at Sunchon. And the second test was carried out during harvesting season in a steel bin with 272.2ton of paddy at Ulsan. At the first test, initial paddy temperature of 23.6$^{\circ}C$ was dropped to 14$^{\circ}C$, and initial moisture content of 19.9% was dropped to 19.3% after 52.5 hours of cooling. At the second test, initial paddy temperature of 16.1$^{\circ}C$ dropped to 5.5$^{\circ}C$ after 78.0 hours of cooling. And, at the first test, the average air flow rates of chilled air leaving the grain cooler and penetrating the grain layer were 77.5 ㎥/min and 42.5 ㎥/min, respectively. To prevent leakage of chilled air from plenum chamber of steel bin, which was about 45% of the average air flow rates of chilled air leaving the grain cooler, a proper method was required. The average total power consumption at the first test during summer was 22.1 ㎾ with control of fan damper. At the second test, it was 17.4 ㎾ due to controlling the capacity of compressor with unloading solenoid valve and changing the flow rates of hot refrigerant gas flowing into evaporator and reheater from compressor, resulting in 27% reduction of energy consumption.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.10
• /
• pp.2335-2340
• /
• 2012

The detector is an uncooled detector system that functions inside the thermoelectric cooler (TEC) equipped with features instead of the cooler. The function of the thermoelectric device to control the temperature of the detector based on a function of temperature to prevent degradation of image quality to perform the role, the latest technology trend by removing the thermoelectric device size, cost a lot of effort to reduce has been studied. In this paper, It would be proposed of the actual test result using real chamber environment of for the best TECless algorithm as to minimize the degradation of image quality and obtain the low price of the uncooled detector.

• Journal of Advanced Marine Engineering and Technology
• /
• v.34 no.8
• /
• pp.1100-1106
• /
• 2010

LED(Light Emitting Diode) has the defects of low efficiency and reducement of life cycle as its temperature increases. This research is about an efficient temperature control of the LED. For LED temperature control, it is shown that a heat sink, fan, a one-chip microprocessor and the PID control algorithm are a good cooling system through experiments. Finally. by using the fan as a cooling device and controlling it appropriately, it is proved that the intensity of illumination and the desired temperature can be achieved with consumption of only 2% of the driving power of the LED system through control experiments.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.1
• /
• pp.43-49
• /
• 2015

In recent years, the amount of heat generated inside of the computer has more increased because of high performance, multi-function, miniaturization and light weight. It is necessary to control the effective heat generation to improve performance and life extension of the computer. In this study, thermoelectric cooling system was manufactured using thermoelectric module and was attached to computer in order to control the heat generated inside computer. And the temperature distributions inside computer were experimentally measured and compared with and without thermoelectric cooling system to investigate the effect of cooling system. Also, to estimate the new cooling system which can substitute for the existing computer cooling system, temperature distributions inside computer were calculated by numerical analysis when there was no cooling system and was applied only cooling system to computer.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2002.04a
• /
• pp.16-17
• /
• 2002

재생냉각은 엔진 경량화 및 높은 추력을 발생시킬 수 있으며 엔진이 장시간 작동할 경우에도 추력의 변화가 일어나지 않는 우수성으로 인해, 액체로켓엔진에서 보편적으로 사용되고 있는 냉각방식이며, 고성능 액체로켓엔진 개발에 있어서 핵심기술이다. 일반적으로 재생냉각 방식은 연소기 내벽에 형성된 냉각유로에 연료 또는 산화제를 흘려보내 고온고압의 연소실내에 온도 경계층을 생성시키면서 벽면온도를 적정온도 이내로 유지하는 것이 목적이며, 또한 냉각유로에서의 압력강하가 추진제 공급 시스템의 공급 압력의 한계값을 넘어서지 않도록 하며, 냉각후의 연료 또는 산화제의 열역학적 상태가 엔진 작동 조건에 적합하도록 제어하여야 한다.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.9 no.11
• /
• pp.1291-1296
• /
• 2014

The thermoelectric cooler is receiving great interest because of advantages such as the precise temperature control capability, the compact and lightweight cooler, and the mechanical vibrationless structure which enhances the reliability compared with the existing vapor compression cooler. However, it is not easy to design the optimal thermoelectric cooler which appropriate to the application because the thermal analysis should be necessary required. Accordingly, this paper studies the methodology of the modelling, sizing and thermal analysis of the thermoelectric cooler using SINDA/FLUINT analysis tool.

• ICROS
• /
• v.15 no.1
• /
• pp.37-43
• /
• 2009

철강제조공정에서 강판을 만드는 공정이 압연이다. 압연공정은 연속주조 공장에서 생산되는 Steel Slab, Bloom, Billet등의 반제품을 높은 온도로 재 가열하고 물리적인 힘을 가해 압연하는 열간압연(이하 열연)과 열연으로 얇아진 강판을 열을 가하지 않고 냉각상태에서 압연하는 냉간압연으로 나뉜다. 본 원고에서는 열연 공정의 가열로 온도제어에 적용한 MFA(Model Free Adaptive Controller)를 소개하고자 한다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.451-454
• /
• 2003

The Oil Coolers is very important unit for the stable thermal performance in machine tools, semiconductor equipments and high precision measuring systems. To select a proper oil cooler for the temperature control of core unit in a machine, not only cooling ability but also static and dynamic sensitivity of temperature sensors are considered. In this paper, the relationship between cooling ability and inflow oil temperature is identified. The cooling ability is increased with the increase of inflow oil temperature. The oil temperature control errors of a cooler are influenced by mainly sensitivity of temperature sensors and heating velocity in a machine. The validity of error cause analysis for temperature control is proved by real cooling experiments with inflow and outflow temperature sensors.