• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.3
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• pp.317-329
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• 1996

By describing the floor slab of a radiant heating system as a one dimensional transient heat exchanger problem, a dynamic analysis model to incorperate with TRNSYS program was developed and their results were compared with experimental results. Results showed that the both of TPOC(Two Parameter On-off Control) and TPSC(Two Parameter Switching Control) method using room air temperature and floor surface temperature as the control parameters does not maintain room air and floor surface temperature exactly at the setting temperatures. But TPSC method is a better candidate for the temperature regulations of room air and floor surface temperature than TPOC method which can keep on the upper and lower limit temperature according to outside temeperature and wall structure etc. And better thermal circumstance can be given by TPSC method than On-off and TPOC method and the overheating which can be occured at the radiant floor heating system with on-off heating control will be reduced.

• Journal of the Society of Naval Architects of Korea
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• v.31 no.4
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• pp.139-146
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• 1994

In this paper a feasible way toward the automation for plate forming by line heating method is proposed. For this a mechanical model representing the line heating phenomenon is adopted and a reasonable algorithm is introduced to search the heating path under the given heating conditions, which can produce the surface very similar to the given surface. A computer program system has been developed according to the proposed algorithm here. It has been applied to two curved shapes to show its validity. From the results it has been found that the proposed algorithm and the developed computer program system give a good result and can be a possible way getting to the automation system of plate forming by the line heating method.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.293-298
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• 2012

The purpose of this study is performance validation of district heating apartments about heating energy consumption and analysis of energy consumption by unit characteristics. The heating energy consumption of the existing apartments was analyzed and the analyzed results will be used for energy saving technology development and policy making. The heating energy consumption data about total 78 apartment complexes, 56,910 units in Gangnam-Gu, Seoul, Korea were investigated from October, 2010 to April 2011. The analysis results are as follows; The mean heating energy consumption is 98[kWh/m2]. The energy consumption of Apgujung-Dong, Daechi-Dong is higher than that of mean valuse. The energy consumption deviation by deterioration, unit area, core type and regional group is very high. Specially, building deterioration casts a long shadow.

• Journal of the Korean Solar Energy Society
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• v.32 no.5
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• pp.59-67
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• 2012

In this study,the compact type solar thermal and ground coupled heat pump hybrid system for space heating/cooling and hot water supply has been developed. This hybrid system was installed in Zero Energy Solar House(ZeSH) in KIER for the demonstration. The thermal performance and operational characteristics of this hybrid system were analysed especially. The results are as follows. (1) This hybrid system was designed in order to address the existing disadvantages of solar thermal/ground coupled heat pump system. For this design, all parts except solar collector and ground coupled heat pump were integrated into a single product in a factory. The compact type unit includes two buffer tanks, an expansion tank, pumps, valves, a controller, etc. This system has an advantage of easy installation with simple plumbing work even in narrow space. (2) The thermal charging and discharging time of the buffer tanks and its characteristics by ground coupled heat pump, and heat pump COP according to geo-source temperature and buffer storage temperature have been studied. This system was found to meet well to the heat load without any other auxiliary heating equipment. (3) The operating hours of the ground coupled heat pump as a backup device of solar thermal can be reduced significantly by using solar heat. It was also found that the minimum heating water supply setting temperature and maximum cooling water supply setting temperature make an influence on the heat pump COP. The lower heating water and the higher cooling water temperature, the higher COP. In this respect, the hybrid system's performance can be improved in ZeSH than conventional house.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.6
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• pp.12-17
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• 2000

IN induction heating system the high frequency operation allows a rapid response to current fluctuation in the inverter and result in improved welding quality. To work induction heating of nonferrous metals, a welding power supply is need high working frequency and high power. This paper is shown design technique for increasing working frequency in induction heating for welding coppers. A series-parallel resonate inverter consists of H-type bridges, each of whose arms is composed of a combination of two parallel IGBTs. Inverter operating with the fixed frequency is controlled by pulse width modulation (PWM). As switching adapted the Zero-Voltage Switching technique to reduce switching losses the system is high efficiency. The propose inverter has feature which is high efficiency for very wide load variations with a narrow range of duty cycle ratio control and load short circuit capability. Detailed experimental results obtained from a 48[V] output, 500[W] experimental inverter are presented to verify the concept.

• Journal of the Korean Solar Energy Society
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• v.25 no.3
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• pp.27-35
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• 2005

In this paper, a thermodynamic analysis was performed to provide design data for a double-effect absorption heating system with water-LiBr-LiSCN mixture which utilizes solar energy as evaporator heat source. In addition, a comparative study of the water-LiBr-LiSCN mixture against the water-LiBr pair was conducted by a computer simulation. The computer simulation is based on mass, material and heat balance equations for each part of the system. Coefficients of performance and flow ratios for effects of different operating temperatures are investigated. It is found that the heating COP is higher for the water-LiBr-LiSCN mixture than for the water-LiBr pair, and FR is lower for the former.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.973-978
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• 2009

In this study, the thermal environment characteristics of On-Off control and thermal difference proportional control method in floor radiant heating system were researched by computer simulation. For the analysis of unsteady heat transfer phenomena in household, the method of using electrical equivalent R-C circuit is applied, and radiation heat transfer between panel, ceiling and walls in household is calculated by enclosure analysis method. The parametric study on two control methods, conventional on-off control and temperature error based time control(T.E.B.T.C.) method, are performed to compare thermal heating control performances, respectively.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.1911-1913
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• 1998

This paper has described about a SEPP Inverter for induction heating load. It is analyzed theoretically about the Inverter operation for induction heating. According to the parameters of induction heating load, it is proposed a method of circuit analysis and operation characteristics of the Inverter. In addition, the soft switching technology known as ZVS(Zero Voltage Switching) is used to reduce turn on and off loss at switching. The Proposed inverter shows it can be practically used as power source system for high frequency induction heating appliancs.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.6
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• pp.673-680
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• 2019

This study investigates the validity of applying new carbon nanotube (CNT, Carbon Nano Tube) surface heaters, which are applied in combination with various products, to the vessel's materials, and proposes the commercializable products accordingly. In order to actually apply a CNT surface heating system technology to the ship's equipment for the first time in Korea, we carried out the interview of experts in the technology field and the due diligence of the shipyard, and presented the technology road map for the selected three items. Finally, for "Heating System of Ship Fuel Tank" with the highest commercialization potential, we proposed a conceptual diagram to enable the final development of the product through the product analysis.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.1
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• pp.95-103
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• 2008

Proposed induction-heated system is innovative system which applied special high-frequency power circuit technique for thermal converse technique and IH(Induction-Heating) magnetic induction heating generated from induction-heated metallic package that is for distillation unit. In this occurs not burning, so that the working environment can be improved. This electromagnetic induction heating technique is used high frequency inverter. By using high frequency inverter high frequency alternative current (HFAC) in the range of [kHz] can be made with conventional alternative current. In this contribution IGBT module is used for high frequency inverter. In this paper are discussed action analysis and characteristics analysis of 1.5[kW]-Class half-bridge resonant inverter system and resonant metallic package. In addition, by using this system, how two step heating superheated steam generator is developed and application of system are also discussed.