• Journal of Industrial Technology
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• v.25 no.B
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• pp.135-140
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• 2005

Voltage of radiometer is measured experimentally using the radiation apparatus in each case of iron- and copper-plates as specimen heating device. The length between radiometer and conical shield and the temperature of specimen heating device are considered as variables. The length between radiometer and conical shield controls the amount of radiation from the specimen heating device. Emissivity for both iron-and copper-plates are calculated by using Stefan-Boltzmann equation. One of results shows that emissivity for both materials increases as the length between radiometer and conical shield increases.

• Journal of the Korean Society of Radiology
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• v.9 no.3
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• pp.131-137
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• 2015

The purpose of this study is to warm up the conventional X-ray table by inventing and design for X-ray table with an attached heating device using less unloaded X-ray, CNT (carbon nano tube) heating element. Configuration of the product design for adhesive carbon heating element X-ray is composed of a conventional X-ray table, carbon nano tube planar heating element, an electrode line, flame resisting protective film, and the bottom film. Characteristics and advantages of this invented product is to provide gentle feeling, the sense of security, and eliminating anxiety to the patient wearing a patient gown and feel the cool air while receiving the test. Thus we are strongly recommend to use this device in the clinical situation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.2
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• pp.136-141
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• 2021

Heating cables, widely used in office buildings, factories, streets and railways, deteriorate in electrical insulation during operation. The insulation deterioration of heating cables leads to electric discharges that can cause electrical fires. With this background, this paper dealt with a condition monitoring technique for heating cables by the analysis of discharge signals to prevent electrical fires. Insulation deterioration was simulated using an arc generator specified in UL1699 under AC operation, and the characteristic and propagation of discharge signals were analyzed on a 100 meter-long heating cable. Discharge signals produced by insulation deterioration were detected as a voltage pulse because they are as small as a few mV and they are attenuated through propagation path. The frequency spectrum of discharge signals mainly existed in the range from 70 kHz to 110 kHz, and the maximum attenuation of the signal was 84.8% at 100 meters away from the discharge point. Based on the experimental results, a monitoring device, which is composed of a high pass filter with the cut-off frequency of 70 kHz, a comparator, a wave shaper and a microprocessor, was designed and fabricated. Also, an algorithm was designed to discriminate the discharge signal in the presence of noise, compared with the pulse repetition period and the number of pulse counts per 100ms. In the experiment, the result showed that the prototype monitoring device could detect and discriminate the discharge signals produced at every discharge point on a heating cable.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.1
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• pp.86-92
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• 2022

Despite otherwise advantageous properties, the performance and reliability of devices manufactured in β-Ga₂O₃ on semi-insulating Ga₂O₃ substrates may degrade because of poorly mitigated self-heating, which results from the low thermal conductivity of Ga₂O₃ substrates. In this work, we investigate and compare self-heating and device performance of β-Ga₂O₃ MESFETs on substrates of semi-insulating Ga₂O₃ and 4H-SiC. Electron mobility in β-Ga₂O₃ is negatively affected by increasing lattice temperature, which consequently also negatively influences device conductance. The superior thermal conductivity of 4H-SiC substrates resulted in reduced β-Ga₂O₃ lattice temperatures and, thus, mitigates MESFET drain current degradation. This, in turn, allows practically reduced device dimensions without deteriorating the performance and improved device reliability.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.197.2-197.2
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• 2010

The study on the operation characteristics of solar space and water heating system with ground source heat pump (GSHP) as a back-up device was carried out. This system, called solar thermal and geothermal hybrid system (ST/G), was installed at Zero Energy Solar House II (KIER ZeSH-II) in Korea Institute of Energy Research. This ST/G hybrid system was developed to supply all thermal load in a house by renewable energy. The purpose of this study is to find out that this system is optimized and operated normally for the heating load of ZeSH-II. Experiment was continued for seven months, from October to April. The analysis was conducted as followings ; - the contribution of solar thermal system. - the appropriateness of GSHP as a back-up device. - the performance of solar thermal and ground source heat pump system respectively. - the adaptation of thermal peak load - the operation characteristics of hybrid system under different weather conditions. Finally the complementary measures for the system simplification was referred for the commercialization of this hybrid system.

• Journal of Energy Engineering
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• v.27 no.4
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• pp.20-26
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• 2018

As the global warming due to greenhouse effect has become serious problem, it is necessary to introduce the technology, for instance, such as diversity or saving of energy to reduce the use of fossil fuel. The purpose of this study was to investigate the characteristics on materials of absorption plate, unpowered and minimum use of power in cooling and heating combined device. As the results, it was observed that, in case of summer, since temperature of absorption device of solar heat(ADSH) was lower than that of no ADSH, cooling effect was insignificant in case of being not installed cold-reservoir. However, in case of winter, heating effect was certified even though the power was not used. At secondhand, the performance of ADSH with Cu was higher 2 times than that of ADSH with Al.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.1
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• pp.49-56
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• 2014

In this study, the generation efficiency of the limited area of a concentrator solar cell was increased by using a solar concentrator and a tracking device. Heat generated by the solar cell was collected using a thermal absorber for supplying hot water or heating. Thus, the concentrator solar cell system provided electricity and heat simultaneously. Tracking of the sun by detecting the sun's position, repositioning of heating device towards the east after sunset, and shutting down of system after sunset were successfully implemented using an illuminance sensor (CdS) and Simulink, a commercial software package. We performed parametric analysis of the velocity, fin installation, and entrance location with respect to the operating temperature of the concentrator solar cell. A heat transfer simulation model was developed for comparing the actual temperature profiles of the concentrator solar cell and thermal absorber, and good agreement was found between the results of the simulations and the experiments.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.4
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• pp.320-326
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• 2019

Recently, the application of atmospheric plasma technology in air filtration is increasing. Sterilization by an atmospheric plasma device is very effective. However, ozone gas, which is generated during atmospheric plasma formation, poses a hazard to human health. To reduce the ozone gas during plasma discharge, we fabricated a one-plate hybrid plasma discharge device with a heating element, which can decompose ozone gas effectively by a simple heating action. In this study, we evaluated the plasma discharge characteristics and ozone concentrations with various Ar flow rates and temperatures. With increasing Ar gas flow rate, the ozone concentration and spectrum intensity increased till an Ar gas flow rate of 60 sccm, and decreased thereafter. When discharged in high temperature, the ozone concentration and spectrum intensity decreased. Further, to evaluate the state of the treated surface under various plasma discharge and heating conditions, we measured the variation in the contact angles on the surface. Regardless of the temperature, the contact angle increased with increasing discharge voltage. However, the contact angle increased when discharged at high temperature.

• Journal of the Korean housing association
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• v.15 no.1
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• pp.33-40
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• 2004

Considering the present development situation of rental apartment since 1982, the supply of rental housing for low-income dwellers has contributed a amount of quantities, but has been deficient qualities in housing policy. To propose the device of remodeling for low-income dwellers in deteriorated apartment, this study investigated the energy consumption of central heating system and the characteristics of maintenance cost in permanent rental apartment. The results of evaluation of alternative heating systems by Life Cycle Costing in permanent rental apartment were as follows; From Life Cycle 15∼20 years by Present Worth Method, the economic heating system of remodeling is central heating system (heat source: B-C oil), unit heating system(natural gas), central heating system(natural gas) in order.

• Journal of the Korean Institute of Gas
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• v.19 no.4
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• pp.49-54
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• 2015

The purpose of this study is to assess the risk of depending on the presence or absence of safety device of domestic heating and drying furnaces, by derivation and analysis of accident frequency of safety devices through FTA (Fault Tree Analysis). Installation standards are lacking in Korean for the safety device of LPG heating and drying furnace, which have a risk of explosion due to structure to trap the leaked gas. Four different safety devices were selected on the basis of NFPA and national standards for combustors of other equipment. Effects of frequency reduction in accidents were analyzed before and after installing the safety devices respectively. As a result, a minimal leakage safety device was presented for preventing damages from gas leak of domestic LPG heating and drying furnace.