• Title/Summary/Keyword: Planar Surface Heater

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An Experimental Study on the Application in-situ of Curing Method by Planar Surface Heater for Cold Weather Concreting (전기발열시트 표면가열 양생공법의 현장적용 연구)

  • 김형래;조호규;김찬수;지남용
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2003.05a
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    • pp.19-22
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    • 2003
  • The purpose of this study is to analyze the curing effect of planar surface heater for concreting in cold weather. Some experiments were conducted to evaluate the temperature history of concrete structures cured with heating sheets. Results are as follows ; (1) The temperature of concrete showed continuously rising trend with the heating by planar surface heater under the cold environmental condition of 3~-12$^{\circ}C$. And after about 24 hours the maximum temperature of concrete was reached at 25~3$0^{\circ}C$. (2) The temperature of slab concrete heated by planar surface heater of 130W/$m^2$ was at least $25^{\circ}C$ higher than that of an exterior air, and the curing performance was much more effective than heating by hot wind machine. (3) Through the curing by planar surface heater for 48 hours, the concrete maturity of about 1.5 times to heating by hot wind machine was acquired.

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An Experimental Study on the Curing and Temperature History of Cold Weather Concrete by Planar Surface Heater (전기발열시트에 의한 한중콘크리트의 양생 및 온도이력에 관한 실험 연구)

  • Kim, Hyung-Rae;Cho, Ho-Kyu;Kim, Chan-Soo;Jee, Nam-Yong
    • Journal of the Korea Institute of Building Construction
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    • v.3 no.2
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    • pp.135-139
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    • 2003
  • The purpose of this study is to analyze the curing effect of planar surface heater for concreting in cold weather. Some experiments were conducted to evaluate the temperature history of concrete cured with heating sheets in the laboratory conditions. As the results, It was showed that the 130W/$m^2$-heater could raise the inner temperature more than $20^{\circ}C$ under the environmental condition of -5~$-20^{\circ}C$. And the temperature of concrete cured by the 200W/$m^2$-heater was 5~$10^{\circ}C$ higher than that of concrete cured by 130W/$m^2$-heater. Finally, through the curing by the planar surface heater during the first 1.5~2 days, it is possible to secure the sufficient maturity of concrete.

Heating Characteristics of Planar Heater Fabricated with Different Mixing Ratios of MXene-CNT-WPU Composites (MXene-CNT-WPU 복합소재 기반 면상발열체의 배합 비율에 따른 발열 특성)

  • Hyo-Jun, Oh;Quy-Dat, Nguyen;Yoonsik, Yi;Choon-Gi, Choi
    • Clean Technology
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    • v.28 no.4
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    • pp.278-284
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    • 2022
  • This study presents an excellent planar heater based on low-dimensional composites. By optimizing the ratio of 1D carbon nanotubes (CNT) and 2D MXene (Ti3C2TX), it is possible to create a planar heater that has superior electrical conductivity and high heat generation characteristics. Low-dimensional composites were prepared by mixing CNT paste and MXene solution with eco-friendly waterborne polyurethane (WPU). In order to find the optimal mixing ratio for the MXene-CNT-WPU composites, samples with MXene to CNT weight ratios of 3:1, 1:1, 1:3, 1:7, and 1:14 were investigated. In addition to these different weight ratios, 5 wt% WPU was equally applied to each sample. It was confirmed that the higher the weight ratio of CNT, the lower the sheet resistance and the higher the heating temperature. In particular, when the MXene-CNT-WPU planar heater was fabricated by mixing MXene and CNT at a weight ratio of 1:7 and 1:14, the heating temperature was higher than the heating temperature of a CNT-WPU planar heater. These characteristics are due to the optimized mixture of the 1D materials (CNT) and the 2D materials (MXene) causing the formation of a flat surface and a dense network structure. The low-dimensional composites manufactured with the optimized mixing ratios found in this study are expected to be applied in flexible electronic devices.

An Experimental Study on the Manufacturing Method and Performance of Planar Thick Film Heaters for Electric Vehicle Heating (전기자동차의 난방용 면상 후막히터의 제조방법과 성능에 관한 실험적 연구)

  • Chae-Yeol Lee;Jong-Han Im;Jae-Wook Lee;Sang-Hee Park
    • Journal of the Korean Society of Industry Convergence
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    • v.27 no.3
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    • pp.685-692
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    • 2024
  • Currently used heating elements are metal and non-metal heating elements, including various types of heaters, and resistance line heating elements have a problem of decreasing thermal efficiency over time, so to solve this problem, a planar heating element using high-purity carbon materials and oxidation-resistant inorganic compounds was applied. Through the manufacture of planar heating elements using CNT, ruthenium composite materials, and ruthenium oxide, physicochemical performance and capacity were increased, and instantaneous responsiveness was increased. Through thick film technology applicable to various base bodies, fine patterns were formed by the screening method in consideration of the fact that the performance of the heat source depends on the viscosity and pattern shape. The heating element was manufactured by thick film printing technology by mixing ruthenium oxide, CNT, Ag, etc. The characteristics of each paste were analyzed through viscosity measurement, and STS 430 was used as a base. Surface temperature and efficiency were measured by testing heaters manufactured for small wind tunnels and real-vehicle experiments. The surface temperature decreased as the air volume increased, and the optimal system boundary was found to be about 200 mm. Among the currently used heating elements, this paper manufactured a planar heating element using thick film technology to find out the relationship between air volume and temperature, and to study the surface temperature.

Abnormal current-voltage characteristics of $SnO_2$ oxide semiconductor and their application to gas sensors ($SnO_2$ 산화물 반도체의 비정상적 전류 - 전압 특성과 가스센서로의 응용)

  • Lee Kyu-chung;Yoon Ho-Kun;Hur Chang-Wu
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.8 no.7
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    • pp.1436-1441
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    • 2004
  • Abnormal current-voltage characteristics of an oxide semiconductor have been investigated and a novel method of detecting reducing gases utilizing self-heating mechanism of sensing layer without an additional heater has been developed. Planar-type sensors based on WO3-doped SnO2 were fabricated using a screen-printing technique. The applied voltage across the sensing layer caused heating of the sensing layer and the current abruptly varied upon exposure to a gas mostly as a result of surface reactions. A unique and fascinating aspect of the gas sensing scheme is that no additional heater is necessary for detection. The new sensing method has been applied to C2H5OH gas in this preliminary work.