• Transactions of Materials Processing
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• v.32 no.3
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• pp.153-159
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• 2023

This paper presents the optimal design of a heating system using radiant heating elements for application in smart farms. Smart farming, an advanced agricultural technology, is based on artificial intelligence and the internet of things and promotes crop production. Temperature and humidity regulation is critical in smart farms, and thus, a heating system is essential. Radiant heating elements are devices that generate heat using electrical energy. Among other applications, radiant heating elements are used for environmental control and heating in smart farm greenhouses. The performance of these elements is directly related to their electrical energy consumption. Therefore, achieving a balance between efficient electrical energy consumption and maximum heating performance in smart farms is crucial for the optimal design of radiant heating elements. In this study, the size, electrical energy supply, heat generation efficiency, and heating performance of radiant heating elements used in these heating systems were investigated. The effects of the size and electrical energy supply of radiant heating elements on the heating performance were experimentally analyzed. As the radiant heating element size increased, the heat generation efficiency improved, but the electrical energy consumption also increased. In addition, increasing the electrical energy supply improved both the heat generation efficiency and heating performance of the radiant heating elements. Based on these results, a method for determining the optimal size and electrical energy supply of radiant heating elements was proposed, and it reduced the electrical energy consumption while maintaining an appropriate heating performance in smart farms. These research findings are expected to contribute to energy conservation and performance improvement in smart farming.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.3
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• pp.40-51
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• 2008

This research presents a new active auxiliary resonant snubber with for induction heating PWM high frequency inverter solving the problem of induction heating PWM high frequency inverter circuit which is using widely in the practical application of an induction heating apparatus, the soft switching operation and power control are impossible when the lowest power supply in the active auxiliary resonant snubber with for induction heating PWM high frequency inverter. The inverter circuit which is attempted by the on-off operation of a switch has the effect of reducing the power loss due to soft switching and high frequency switching. This confirms that power regulation is possible on a continuous basis from 0.25[kW] to 2.84[kW] where the duty factor(D) changes from 0.08 to 0.3 under zero current switching which operates by an asymmetrical pulse width modulating control. The power conversion efficiency is 95[%]. Due to these results, the active auxiliary resonant snubber for an induction heating PWM high frequency inverter is considered effective as a source of induction heating.

• Journal of Soil and Groundwater Environment
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• v.11 no.1
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• pp.45-53
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• 2006

This study was performed to evaluate the heating characteristics of soils for the application of electrical resistance heating process combined with soil vapor extraction. Laboratory tests were conducted to find out optimum heating conditions by the adjustment of electrical supply and electrode. Results show that fine soil particles are more efficient for electrical heating. As water content of soil increases, more efficient electrical heating is observed. However, as the soil is saturated with water above the soil porosity, decrease in the heating efficiency is observed. The higher the voltage, is and the shorter the distance between the electrodes is, the better the heating efficiency is. The soil contaminated by fuel is also more efficient than non-contaminated soil in electrical resistance heating. From the relationship between the intial electrical current and the conductivity obtained in this study, soil temperature by electrical heating can be estimated.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.6
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• pp.500-504
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• 2020

Heating films were prepared with composites of poly (methyl methacrylate) and conductive graphite. The as-prepared composite was deposited on a PET film and then fabricated using a bar coater to produce a film with uniform thickness. Copper electrodes were attached to both ends of the as-prepared film, and the heating characteristics of the film were analyzed while applying a DC voltage. The electrical conductivity and heating temperature of the heating films depended on the size, structure, content, and the dispersion characteristics of the graphite in the composite. The thermal energy was adjusted by controlling the electrical energy, based on the Joule heating theory. The electrical resistance of the film was altered in proportion to Ohm's law, and the heating temperature was changed according to the structure of the film (interelectrode spacing or electrode length) and the conductive graphite content. When the content of conductive graphite in the film increases, the electrical resistance decreases, and the heating temperature increases; however, there is no significant change above a certain content (50%).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.12
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• pp.1602-1610
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• 2018

Induction heating can convert electrical energy to thermal energy with high conversion efficiency and quick heating. Currently, a current source rectifier/inverter-fed parallel resonant circuit is widely used as an induction heating power supply for forging applications. However, the conventional induction heating power supplies composed of phase-controlled rectifier and SCR inverter have low efficiency and low power factor at input side, and require additional starting circuitry. So this paper proposes new induction heating power supply topologies for forging applications which have high power factor, high efficiency, and large output power. It also suggests detailed design guideline.

• Journal of the Korean Ceramic Society
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• v.55 no.5
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• pp.440-445
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• 2018

To control the electrical properties of a SiC heating element, we sintered $SiC-ZrB_2$composites by using the spark plasma sintering method. The addition of $ZrB_2$ particles with lower electrical conductivity to the SiC matrices with comparatively higher electrical resistivity lowers the electrical resistivities of the composite material. The $ZrB_2$ particles aggregate to form large particles and 3-1, 3-2, and 3-3 networks, i.e., conduction paths. In our study, about $1-{\mu}m$-sized $ZrB_2$ powders start to form the conduction path at about 10 vol.% of addition, namely the threshold volume. The Joule heating experiment shows that 20 vol.% $ZrB_2$-added SiC heating element has outstanding heating efficiency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04c
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• pp.10-14
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• 2008

In this paper, abnormal heating of circuit breaker in panel board by poor connection was studied. Firstly, calculation method of contact resistance shown in IEC 60943 was examined. Secondly, concerning abnormal heating of circuit breaker in panel board, field measurements were performed. Field measurements showed that locally abnormal heating by poor connection could be detected, therefore, in that case, immediate action was needed. Finally, experiments regarding abnormal heating between terminal of circuit breaker and electric wire were conducted. The results showed that abnormal heating above $180^{\circ}C$ was measured. Also, in the results of analysis of electrical waveforms according to load current, voltage drop occurred around poor connection, and the oxide was generated according to mechanical vibration. In order to prevent electrical disaster caused by poor connection, adequate torque should be applied to electrical connection, and periodic check-ups are needed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.3
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• pp.24-30
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• 2012

A proposed the electrical fan heater using induction heating is innovative system which applied IH(Induction Heating) magnetic induction heating generated from induction-heated metallic package and high-frequency power circuit technique for thermal converse technique. In this occurs not burning, so that the working environment and deterioration of products can be improved. The existing heater that low efficiency by heated resistance or using fossil fuel of coal, diesel, kerosene has problems about burden for high cost price. In this paper are compared efficiency the existing heaters and designed electrical fan heaters using 3[kW]-Class full-bridge resonant inverter. In addition, action analysis and application of system are discussed.

• Journal of the Korean Applied Science and Technology
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• v.32 no.3
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• pp.405-411
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• 2015

Carbon composites for flexible fiber heating element were examined to improve the electrical conductivity in this study. Carbon composites using carbon black, denka black, super-c, super-p with/without CNF or dispersant such as BCS03 and Sikament-nn were prepared. Carbon composite slurry was coated on plane film and yarns(cotton, polyester) and the performances of prepared heating materials were investigated by checking electrical surface resistance, adhesion strength. The plane heating element using carbon black under natural drying condition($25^{\circ}C$) had better physical properties such as surface resistance(185.3 Ohm/sq) and adhesion strength(above 90%) than those of other carbon composite heating elements. From these results, polyester heating element coated by carbon black showed better electrical line resistance(33.2 kOhm/cm) than cotton heating element. Then, it was found that polyester heating element coated by carbon black with CNF(3 wt%) and BCS03(1 wt%) appeared best properties(0.604 kOhm/cm).

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1405-1407
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• 2001

It was studied to prepare high temperature heating elements using molybdenum disilicide($MoSi_2$). Molybdenum disilicide is widely used as material for manufacturing high temperature heating elements. $MoSi_2$ heating elements could be used at 1700-1900$^{\circ}C$. However, it is relatively expensive, and its demand depends on import. $MoSi_2$ powders was mixed with 4-5wt% of montmorillonites type bentonite as plasticizer and a small amount of $Si_3N_4$, $ThO_2$, and B as additives to prepare specimen of heating elements. Then, it was extruded, dried, sintered and machined followed by heating test. Effects of sintering conditions and amount of additives were investigated, It was sintered effectively at 1,350$^{\circ}C$ for five hours. Electrical resistivity was decreased with increasing of sintering temperature and time, and related with apparent density of the specimens. It was linealy decreased with increasing of sintered density. The heating elements thus prepared was stable at 1700$^{\circ}C$ and the physical properties such as specific electrical resistivity, hardness, apparent density, thermal expansion coefficient, and bending strength were almost identical with those of commercial heating elements.