Excellent Thermal Dissipation Performance of the Paint Prepared with Graphene

전제홍,김현중,방석진,조지운,신안섭,박진환 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

Heat dissipation systems are one of the important goals for the continued development of the electronics industry. And heat sinks are the most widely used in thermal management systems, however the heat dissipation efficiency is usually limited. Therefore, in this study, in order to increase heat dissipation efficiency of the heat sink, heat dissipating paint using graphene as a thermal conductive additive was designed and evaluated. The heat dissipation performance of the heat-dissipating paint was calculated from the temperature difference between the paint-coated and -uncoated specimens mounted on the heat source. In the paint using graphene as a thermally conductive filler, the highest heat dissipation performance was achieved at a 1/50 ratio of graphene to the resin, and a 6.5°C reduction was achieved.

레일 체결구 결함 검측 모듈의 방열성능 개선을 위한 열 해석

채원규,박영,권삼영,이재형,Chae, Won kyu,Park, Young,Kwan, Sam young,Lee, Jaehyeong 한국전기전자재료학회 2016 전기전자재료학회논문지 Vol.29 No.2

In this paper, various heat dissipation designs for a rail anchoring failure detection module were investigated by a thermal flow analysis. For the detection module with the heat dissipation design on the overall housing surface, an average temperature inside the module was lowered by $25^{\circ}C$ when compared to no heat dissipation design. In addition, an internal heat-flow blocking layer and an heat conduction layer inserted between the LED module and housing case were effective in reducing the temperature in the rail anchoring failure detection, which has a limited space for installation and little air flow. Especially, the temperature near LED module decreased below $55^{\circ}C$ when the optimal heat dissipation design was applied.

Numerical Simulation of High Power LED Heat-Dissipating System

Shih-Jeh Wu,Hsiang-Chen Hsu,Shen-Li Fu,Jiam-Nan Yeh 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.2

In this paper, thermal analysis of the heat dissipation under different heat sink for high-power white Light Emitting Diode (LED) is presented. Junction temperature of LED is elevated as the power of LED increases, which brings up deterioration of light efficiency and other side effects. Heat dissipation is another design concern other than material and illumination efficiency. The purpose of this paper is to investigate the cooling of high-power LED chips and modules for design of heat sinks. Three types of heat sinks are designed for a tandem 12-chip module and an extensive numerical investigation of the heat sink design performance is conducted by Computational Fluid Dynamics software Fluent. The effects of heat sink geometry and adhesive material are also investigated. Design variables are the thickness of sink base, number, thickness and length of fins. The total wetted area is the dominant factor to the junction temperature. The objective of design regarding the junction temperatures around 50°C is easily achieved. However, its effect is limited at high values of these parameters, furthermore an excessive number of fins incurs reverse consequence due to problem of ventilation also waste of material.

열교환기 형식에 따른 열교환기의 에너지 및 엔트랜시 성능 특성 해석

김경훈,정영관,한철호 한국수소및신에너지학회 2020 한국수소 및 신에너지학회논문집 Vol.31 No.1

In this work energy and entransy characteristics of heat exchangers are analyzed for 12 different flow arrangements of heat exchangers. The dimensionless parameters are number of entransy dissipation (Ng), number of entransy dissipation-based thermal resistance (Nr), and entransy dissipation-based effectiveness of heat-exchanger (εg). The dimensionless parameters are expressed analytically in terms of the effectiveness of heat exchanger (ε), heat capacity ratio (c), and number of transfer unit (N) for optimal performance of heat exchangers. Results showed that the dimensionless parameters based on the entransy dissipation can be useful concepts for optimal design of heat exchangers.

고 출력, 멀티 칩 LED 벌브에서 방열 거동 해석

문철희 대한금속·재료학회 2018 대한금속·재료학회지 Vol.56 No.3

To ensure the reliability of high-power light-emitting diode (LED) bulbs, temperature management is very important, including reduction of the junction temperature on the LED chip and enhancing outward thermal dissipation. Simulation can be an effective tool for predicting the temperature distribution over all bulbs, which enables a quantitative analysis. In this study, we investigated a high-power LED bulb consisting of 21 LED packages with a single LED chip for each. We experimentally measured the temperature at the surface of the LED bulb using a thermocouple, and a finite volume method (FVM) simulation was conducted for the same position to confirm the accuracy of the prediction model. In addition, thermal equilibrium models based on heat transfer equations are proposed for quantitative analyses using calculations based on the models. Using this method, we explain the effect of the lens on the surface temperatures of the LED bulb and predict the junction temperature. By comparing the analysis of the heat dissipation characteristics from the calculations to the thermal equilibrium models, we determined the accuracy of the FVM simulation in this study for the variation in thermal conductivity of the heat sink. Based on the reliability of the FVM simulation, we investigated the effects of the surface emissivity of the heat sink and heat convection conditions.

A Study of the LED Module Heat Dissipation Structure Suitable

Keum-yeon Choi,Ik-soo Eo 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.8

In this paper, reduces the absolute temperature of the LED module, results of the experiments have been derived a method to improve the suitability heat dissipation structure and properties are as follows. First, FR-4 PCB size in consideration of the PCB LED module air-hole 3mm radius of the LED module area 10%, 20%, 30% ratio after a process of simulation to generate the air-hole on the PCB and the surrounding, 30%, 50×30mm intervals, when generating a fifty-two, applying the air-hole 3mm 10% of the radius of the area LED module obtained the results of temperature reduction than max. about 3.5℃ and min. about 3.1℃. Second, LED array interval and to be suitable experimental structure through the PCB air-hole generation plate type heat-sink for LED module to support the air-hole radius 40mm size to create a two and six and four, as a result of the simulation in progress, when air-hole number pairs of the increase, max. and min. temperature was reduced to obtain a formal conclusion by about 1~1.5℃. the air-hole 3mm 10% of the radius of the area applied LED module than max. about 4.5℃, min. about 4.2℃ results was confirmed reduction. As a result, to the suitable of the heat dissipation even if the LED module PCB material no matter how good, if the heat sink is not well designed structural cannot obtain a large effect.

Switching and Heat-dissipation Performance Analysis of an LTCC-based Leadless Surface Mount Package

Dong Yun JUNG,Hyun-Gyu Jang,Jong-Il Won,Doo-Hyung Cho,Sung-Kyu Kwon,Seong-Hyun Lee,Kun Sik Park,Jong-Won Lim,Yong-Ha Lee 대한전자공학회 2022 Journal of semiconductor technology and science Vol.22 No.1

A leadless surface mount package was developed to enhance the switching and heat-dissipation properties of a power semiconductor. The package was implemented through a low-temperature co-fired ceramic (LTCC)-based multilayer circuit substrate that could form embedded cavities. A silicon carbide (SiC) Schottky barrier diode (SBD) bare die was attached to the cavity in the LTCC substrate. Chip interconnection was realized using a wide and thick copper (Cu) clip with a low parasitic inductance and electrical resistance compared to those of a conventional wire. Silver-filled multiple vias and wide metal planes were used to reduce the electrical parasitic effects and enhance the heat-dissipation of the package. The DC and dynamic characteristics of the 600 V/10 A-class SiC SBD package involving the proposed technologies were evaluated. The dynamic test results indicated that the reverse recovery charge (Qrr) was 18.7% lower than that of a traditional TO-220 packaged product with the same bare die. Furthermore, two leadless commercial products and the proposed package prototype were applied to a power factor correction (PFC) converter, and the power loss and heat-dissipation performances were compared. The proposed package exhibited a lower loss and higher heat dissipation than those of the commercial products.

Reduced thermal resistance of heat sink using graphene oxide decorated with copper nanoparticles

Ryu, Beo Deul,Han, Min,Ko, Kang Bok,Lee, Kyu-Han,Cuong, Tran Viet,Han, Nam,Kim, Kyurin,Ryu, Jae Hyung,Park, Noh-Joon,Lim, Yongsu,Thanh, Do Trong,Jo, Chang Hee,Ju, Kwanseon,Hong, Chang-Hee Elsevier 2019 Materials research bulletin Vol.110 No.-

<P><B>Abstract</B></P> <P>Three–dimensional thermal interface materials made of graphene oxide (GO) and copper nanoparticles (Cu NPs) were applied for enhancing light–emitting diode heat dissipation. The effect of the stacking order of GO and Cu NPs on thermal resistance was explored by creating two types of samples: spray–coated with a mixed GO–Cu NPs and layer–by–layer stacked with GO/Cu NPs/GO. A reduction of thermal resistance for mixed GO–Cu NPs and layer–by–layer stacked structure by 37% and 33%, respectively, compared to that of Al heat sink. The lower thermal resistance of the mixed GO–Cu NPs sample is attributed to the fact that distributed Cu NPs at the step edge of GO sheets enhances the out–of–plane heat transfer at wrinkles/folds of GO interlayers. Therefore, a mixed GO–Cu NPs is considered as a promising composite for effective thermal management of high–performance optoelectronic devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Three–dimensional thermal interface materials made of graphene oxide and copper nanoparticles (GO–Cu NPs) have synthesized. </LI> <LI> The effect of the stacking order of GO–Cu NPs on thermal resistance has explored for enhancing LED heat dissipation. </LI> <LI> Analysis by a FLIR camera has showed that the combination of GO and Cu NPs enabled heat dissipation properties. </LI> <LI> The thermal resistance of the mixed GO–Cu NPs structure is less 37 % than that of the Al heat sink. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

태양광 패널 적용 방열용 탄소소재의 제조 및 열전달 수치해석

박헌수(Hun-Su Park),강철희(Chul-Hee Kang),김홍건(Hong-Gun Kim) 한국기계가공학회 2019 한국기계가공학회지 Vol.18 No.12

This analysis demonstrates the effective removal of heat generated from a solar panel"s output degradation factor solar cells (the solar panel’s output deterioration factor), and solves the problems of oxidation and corrosion in existing metal heat sinks. The heat-dissipating test specimen was prepared using carbon materials; then, its thermal conductivity and its effectiveness in reducing temperatures were studied using heat transfer numerical analysis. As a result, the test specimen of the 30g/m2 basis weight containing 80% of carbon fiber impregnated with carbon ink showed the highest thermal conductivity 6.96 W/(m K). This is because the surface that directly contacted the solar panel had almost no pores, and the conduction of heat to the panels appeared to be active. In addition, a large surface area was exposed to the atmosphere, which is considered advantageous in heat dissipation. Finally, numerical analysis confirmed the temperature reduction effectiveness of 2.18°C in a solar panel and 1.08°C in a solar cell, depending on the application of heat dissipating materials.

전자파차폐 및 방열 기능을 가지는 하이브리드시트 성능측정

안성수(Sung-Su Ahn) 한국산학기술학회 2021 한국산학기술학회논문지 Vol.22 No.5

본 논문에서는 전자기기 등에서 전자파 차폐 및 방열소재로 많이 채택되는 동 메쉬 시트와 천연그라파이트 시트를 감압 접착제없이 합지시켜 개발된 차폐 및 방열의 기능을 동시에 가지는 하이브리드시트의 성능 측정결과를 제시하였다. 객관적인 방열 성능을 확인하기 위해 2개의 다른 제품들과 수직 및 수평 열전도도를 각각 측정하여 결과를 비교하였으며, 전자파 차폐 성능은 CISPR 11규격에 따른 복사방출시험을 3m 전자파 무향실에서 진행하여 확인하였다. 수직열전도도의 경우 제안된 하이브리드 시트가 방열코팅이 된 알루미늄 시트 대비 약 8.63배, 감압 접착제로 인조 그라파이트를 합지시킨 구리 시트에 비해 18.7배 높은 수준이였으며, 수평 열전도도는 인조 그라파이트를 합지시킨 구리 시트에 비해 약 0.64배, 방열 코팅된 알루미늄 시트에 대해서는 약 1.76배로 나타났다. 동일한 열원에서 각 시트들을 적용 후 측정한 결과에서는 제안된 하이브리드 시트가 열방출 기능이 가장 우수하였고 복사방출시험에서는 방사노이즈들이 상당부분 제거되는 결과를 얻었다. This paper presents the performance measurement results of a hybrid sheet with both shielding and heat dissipation functions developed by laminating copper mesh sheets and natural graphite sheets, which are used widely as electromagnetic shielding and heat-dissipating materials in electronic devices, without a pressure-sensitive adhesive (PSA). The results were compared by measuring the vertical and horizontal thermal conductivity with two other products to confirm the heat dissipation performance. A radiation emission test confirmed the electromagnetic shielding performance using a 3m electromagnetic anechoic chamber according to the CISPR 11 standard. In the case of vertical thermal conductivity, the proposed hybrid sheet was approximately 8.63 times higher than that of an aluminum sheet with heat dissipation coating and 18.7 times higher than that of a copper sheet laminated with artificial graphite with PSA. The proposed hybrid sheet was approximately 0.64 times that of the sheet, and approximately 1.76 times that of the heat-dissipated aluminum sheet in case of horizontal thermal conductivity. Measurements after applying each sheet in the same heat source revealed the proposed hybrid sheet to have the best heat dissipation performance. The radiation emission test showed that significantly radiation noise had been removed.