• Journal of the KSME
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• v.52 no.2
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• pp.39-42
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• 2012

이 글에서는 최근 급속하게 확산 적용되고 있는 고전력 LED 조명에서의 주요 요소기술인 광원냉각기술의 최근 동향을 소개하고, 국부적인 능동냉각으로 면 광원 분포의 성능을 용이하게 제어할 수 있는 자원절약형 친환경 액적열스위치에 대한 개념과 기술적인 관심사에 대해 소개하고자 한다.

• Journal of the Korean Solar Energy Society
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• v.35 no.3
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• pp.81-91
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• 2015

LED has received intensive research attention due to its long life, high efficacy, fast response and wide colour availability, and has secured extensive application areas. However, LED chips within the modules convert only fraction of electric energy into light, and majority of supplied energy needs to be dissipated as heat, which challenges in the performance and life of the LED modules. IEC 62717 specifies the performance requirements for LED modules together with the test methods and conditions. The present study examined the influence of different design parameters on performance temperature through series of experiments and numerical simulations. The economic means to change the module performance temperature during the measurement of mandatory markings were suggested based on predicted cooling performances.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.6
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• pp.152-158
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• 2013

The purpose of this study is to investigate cooling performance of high power LEDs from 100 to 200 W class by using a jet impingement cooling module. The numerical analysis of forced convection cooling inside cooling module is carried out using a multi-purpose CFD software, FLUENT 6.3. In the experiments, the LED cooling system consists of jet impingement module, heat exchanger, water reservoir, and pump. In the present study, the cooling performance of jet impingement cooling module is investigated to determine the effect of the heat sink types on the impinging surface, the space and length of fins. Numerical and experimental studies show the reasonable agreement of LED metal PCB temperature between those results and give the optimized design parameters such as the space of fin and the length of fin. Also, the pin fin type of heat sink is found to be more efficient than the plate type heat sink in jet impingement cooling.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.695-696
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1017-1018
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• 2011

• Journal of the Korean Society for Precision Engineering
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• v.29 no.7
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• pp.778-784
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• 2012

In comparison with some other light sources, LED has merits such as increased life expectancy, fast response, pollution free, and high energy efficiency. Lately, due to development of LED with high brightness and capacity, LED has widely used in many industrial fields such as automotive, aviation, display, transportation and special lighting applications. Since the high heat generation of LED chips can cause a reduction in lifetime, degradation of luminous efficiency, and variation of color temperature, studies have been carried out on the optimization of LED packaging and heat sinks. In this study, experiments on measuring the heat generation rate of LED and the cooling performance of a heat sink were carried for analyzing the thermal characteristics of LED lighting system in free convection. From the results, dimensionless correlation on the cooling performance of heat sink in natural convection was proposed with Nusselt number and Rayleigh number as a guideline for designing cooling device of LED lightings.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.8
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• pp.1100-1106
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• 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 Korean Society of Manufacturing Process Engineers
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• v.17 no.6
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• pp.117-123
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• 2018

Automotive headlamps have been continuously developed as one of the most important devices for securing the driver's view, and the LED lamps are getting popular in recent years. However, in case of the LED lamps, because the heat generated by the LED lamps are too high, it shorten the product life and lower the LED efficiency. Therefore, this study was investigated the cooling characteristics of the LED lamp heat sink for automobile by forced convection for LED heat generation control. In order to analyze the cooling characteristics of the heat sink, the temperature distribution results were investigated through the experiment and computational analysis under the increase of the air flow velocity, and the convective heat transfer coefficient was obtained. Also, convective heat transfer coefficient was calculated by the theoretical formula under the same condition and compared with experimental and computational results. From the result of this study, as the air flow velocity around the heat sink fins increased, the convective heat transfer coefficient significantly increased, confirming the improvement in the cooling effect.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.2
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• pp.142-148
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• 2017

The objective of this study is to investigate the cooling characteristics of a heat sink for an LED headlight used in passenger cars. To this end, this study conducts the experimental and numerical analysis of the heat sink heated at constant heat fluxes without air flow applied. In the experiments, heat was transferred at a constant heat flux through the bottom of a heat sink. The measured temperature on pre-selected locations of the heat sink was in good agreement with the numerically predicted one. The experimental and numerical results indicate that the convective heat transfer coefficient for the natural convection mode was decreased by increasing the heat flux applied to the bottom of heat sink, lowering the cooling capabilities.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.669-670
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• 2012