• KIEAE Journal
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• v.8 no.6
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• pp.3-10
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• 2008

Since fire was founded in the world, human races have invented various heating methods. Ondol is traditional heating method in Korea. It is very the important work to trace the history and characteristics of Ondol which originated and was developed in the Korean peninsula. Especially, the study on Ondol will contribute to improving the present heating methods and predicting future ones. In this paper, we shall study through the analysis of documents such as oriental documents, the document of Choseon dynasty, European documents and American documents. In order to discover the origins of Ondol as one of the excellent heating method all over the world, This study aims at identifying the history and characteristics of Ondol in the Korean peninsula, through document analysis. Results of this study are as follows. 1) The first document about Ondol is Sookyongjoo(水經注), Chinese ancient geography book. Contents recorded in the book include the description related to Ondol at Kwankyesa temple which was located at the border land between Gogooryo(ancient Korea) and the northeast of China. 2) Ondol was popular heating method in Gogooryo(ancient Korea) and it was used in not only Gogooryo but also Silla Kingdom and Beakje Kingdom. Thereafter, it was also used widely in Goryo dynasty and Choseon dynasty. Thereby we know that Ondol has been used as a heating method for a long time in the Korean peninsula. 3) Ondol was covered with a floor paper since the beginning of Choseon dynasty. the paper made room clean and impacted on Korean life style. Because the floor was clean and warm, Koreans thus took off shoes and sat on the floor. 4) Ondol was spreaded to Jeju island in Korea before 16th century but wasn't used widely there. The reason was that Ondol was rare high class heating system and the weather was warm in Jeju island. 5) The overspreading of Ondol caused that poor people built roughly Ondol in the last of Choseon dynasty. So, the quality of Ondol gradually became lower and lower. 6) A westerner was impressed by the novelty of Ondol and Frank Lloyd Wright had played an important role to update and spread Ondol widely all over the world. Hailing Ondol as the ideal heating system, Frank Lloyd Wright began incorporating it in his buildings back in the U.S. and even invented a modified ondol system, using hot water running through pipes instead of the hot exhaust through flues.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.924-930
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• 2018

The objective of this study was to investigate heating performance characteristics of electric heat pump system in a fuel cell electric vehicle (FCEV). In order to analyze heating performance characteristics of electric heat pump system with plate-type heat exchanger using stack coolant to evaporate the refrigerant, R-134a, each component was installed and tested under various operating conditions, such as air inlet temperature of inner condenser and compressor speed. When the air inlet temperature of inner condenser was varied from $0.0^{\circ}C$ to $-20.0^{\circ}C$, heating capacity was not quite different due to similar temperature gap between inlet and outlet of inner condenser with electric-driven expansion valve (EEV). However, COP increased until certain EEV opening, especially under 45.0%, because of decreasing power consumption. According to the compressor speed variation from 2,000 to 4,000 RPM, heating capacity and COP were found to have opposite trend. In the future works, stack coolant conditions as the heat source for tested heat pump system were analyzed with respect to heating performance, such as heating capacity and COP.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.6
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• pp.400-405
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• 2011

This paper presents the heating performance characteristics of the air source heat pump with air to water type. The heating capacity, COP, P-h diagram were measured at various operating conditions, air-side temperatures, relative humidities, and inlet/outlet water temperature under the standard heating condition of KS B 6275. The experimental data for the heat pump were measured using the air-enthalpy calorimeter and the constant temperature water bath. As the air-side temperature increases, the heating capacity and COP increase. The effect of the air-side relative humidities on the heat pump performance is insignificant. The heat pump performance on inlet and outlet water temperatures and air-side temperatures(-7, -11, $-15^{\circ}C$) were studied. Heating capacity and COP increased about 27~39% with the air-side temperature increasing. Enthalpy between the front and the rear of condenser decreased about 6% by increasing of the inlet water temperature. These results can be utilized in the design of the air source heat pump system with air to water type.

• Journal of Power System Engineering
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• v.19 no.4
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• pp.69-75
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• 2015

In this study, the characteristics of heating performance of a high-performance air-cooled heat pump with vapor-injection(VI) cycle using re-heater was investigated experimentally. Devices used in the experiment is consist of a VI compressor, condenser, oil separator, refrigerant (economizer outlet refrigerant) re-heater, economizer, evaporator. And R410A was used as a working fluid. The experiment was conducted with two cycles(cycles A and B) for investigating heating performance. In case of cycle B, heat exchange was conducted by re-heater between outlet refrigerant of compressor and suction refrigerant of the VI system(Fig.1, re-heater). But the re-heater was not used in case of cycle A. As a result of this experiment, discharge temperature of refrigerator in compressor was shown higher value, when the cycle B was conducted, because of the heat exchange between suction refrigerant of VI cycle and outlet refrigerant of compressor in the re-heater than cycle A that was not use re-heater. it means that liquid hammer and the decrement of heating performance can be decreased by using re-heater. Also, Heating coefficient of performance(COPh) was shown about 2.98 in Cycle B which was 4% higher than Cycle A and from these results, It was confirmed that the improvement of the heating performance of heat pump with VI cycle can be achieved by applying re-heater.

• Journal of the Korean Society of Clothing and Textiles
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• v.39 no.2
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• pp.247-256
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• 2015

This study prepared fabric-heating elements of carbon nanofiber composite to characterize morphologies and electrical properties. Carbon nanofiber composite was prepared with 15wt% PVDF-HFP/acetone solution, and 0, 1, 2, 4, 8, and 16wt% carbon nanofiber. Dispersion of solution was conducted with stirring for a week, sonification for 24 hours, and storage for a month, until coating. Carbon nanofiber composite coated fabrics were prepared by knife-edge coating on nylon fabrics with a thickness of 0.1mm. The morphologies of carbon nanofiber composite coated fabrics were measured by FE-SEM. Surface resistance was determined by KS K0555 and worksurface tester. A heating-pad clamping device connected to a variable AC/DC power supply was used for the electric heating characteristics of the samples and multi-layer fabrics. An infrared camera applied voltages to samples while maintaining a certain distance from fabric surfaces. The results of morphologies indicated that the CNF content increased specifically to the visibility and presence of carbon nanofiber. The surface resistance test results revealed that an increased CNF content improved the performance of coated fabrics. The results of electric heating properties, surface temperatures and current of 16wt% carbon nanofiber composite coated fabrics were $80^{\circ}C$ and 0.35A in the application of a 20V current. Carbon nanofiber composite coated fabrics have excellent electrical characteristics as fabric-heating elements.

• Journal of Biosystems Engineering
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• v.25 no.5
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• pp.379-384
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• 2000

In order to use the natural thermal energy as much as possible for greenhouse heating, the air-air heat pump system involved PCM(phase change material) latent heat storage system was composed, and three types of greenhouse heating system(greenhouse system, greenhouse-PCM latent heat storage system, greenhouse-PCM latent heat storage-heat pump system) were recomposed from the greenhouse heating units to analyze the heating characteristics. The results could be concluded as follows; 1) In the greenhouse heated by the heat pump under the solar radiation of 406.39W/$m^2$, the maximum PCM temperature in the latent heat storage system was 24$^{\circ}C$ and the accumulated thermal energy stored in PCM mass of 816kg during the daytime was 100,320kJ. In the greenhouse without heat pump under the maximum solar radiation of 452.83W/$m^2$, the maximum PCM temperature in the latent heat storage system was 22$^{\circ}C$ and the accumulated thermal energy stored during the daytime was 52.250kJ. 2) In the greenhouse-PCM system without heat pump the heat stored in soil layers from the surface to 30cm of the soil depth was 450㎉/$m^2$. 3) In all of the greenhouse heating systems, the difference between the air temperature in greenhouse and the ambient temperature was about 20~23$^{\circ}C$ in the daytime. In the greenhouse without heat pump and PCM latent heat storage system the difference between the ambient temperature and the air temperature in the greenhouse was about 6~7$^{\circ}C$ in the nighttime, in the greenhouse with only PCM latent heat storage system the temperature difference about 7~13$^{\circ}C$ in the nighttime and in the greenhouse with the heat pump and PCM latent heat storage system about 9~14$^{\circ}C$ in the nighttime.

• The Korean Journal of Food And Nutrition
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• v.28 no.4
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• pp.544-550
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• 2015

In order to determine the material characteristics of pork rinds according to the breeds, the chemical composition, color, pH, collagen contents, shear force, fatty acid and amino acid contents of pork rinds were investigated. White pork rinds (WPR) and black pork rinds (BPR) were evaluated before and after heating to compare the differences between breeds and the effects of heating treatment. In the chemical composition test, the respective moisture contents for WPR and BPR before heating were 49.90% and 53.75% but increased to 60.75% and 61.09% after heating. The test for crude protein and crude fat contents showed lower values after heating but WPR was higher than BPR. In the color test, the L value decreased rapidly with heating, dropping from 68.75 to 45.11 in WPR and from 67.22 to 49.64 in BPR. WPR had a higher L value and a lower a value than BPR before heating but had a higher L value and a lower a value than WPR after heating. pH was significantly higher in WPR than BPR regardless of heating (p<0.05). The collagen content for WPR and BPR was 10.38 g/100 g and 11.54 g/100 g but increased to 12.00 g/100 g in WPR and decreased to 11.40 g/100 g in BPR after heating. The shear force of 26.14 kgf in WPR was significantly higher than 12.89 kgf in BPR before heating (p<0.05), but the values decreased significantly after heating in both WPR and BPR. Linoleic acid in WPR was 17.29%, which was higher than 15.13% in BPR. The USFA for BPR was also higher than WPR. In amino acid composition, the EAA contents in WPR was 7,190 mg%, which was higher than 5,520 mg% in BPR.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.6
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• pp.73-82
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• 2005

This study was performed to evaluate the need for heating wastewater to enhance treatment efficiency of organic matter (BOD, SS) during cold winter in newly developed Absorbent Biofilter System (ABS) which was established in the Suwon Campus of the Seoul National University. Treatments consisted of non-heating (2000 year) and heating(2001, 2002 year), and sampled data were analyzed during cold winter period as well as post winter period to investigate the influence of heating after winter season. Even the average air temperature showed only $0.4^{\circ}C$ difference between two experimental years, the difference in the average effluent temperature during cold winter period between heating and non-heating experiment was approximately $11^{\circ}C$. The average effluent concentration of organic matter in non-heating treatment exceeded the Korean standards for water quality of discharged effluent in riparian area (BOD and SS 10 mg/L); however, the standards were met in case of heating treatment during both winter and post winter period. Therefore, the need fur heating wastewater during cold winter season in ABS was justified. On the other hand, there was no improvement of treatment efficiency in T-N and T-p, but we observed the more activated nitrification as increasing the wastewater temperature. Because the average underground temperature was $5^{\circ}C$ higher than the average air temperature during cold winter period, we recommend that the ABS can be established in the underground rather than on-ground for saving the heating cost.

• Proceedings of the KWS Conference
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• 2003.11a
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• pp.86-88
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• 2003

The characteristic of induction heating solder bump(solder ball: Sn-37Pb, Sn-3.5Ag, Sn-3.0Ag-0.5Cu) has analyzed in this paper. The initial condition of induction heating depends on the time and current. The shape of lead-free solder bump is better than lead solder. The shear strength of lead solder bump has decreased with aging time. The average of shear strength of solder bump is about 10N, 11N, and 11N respectively. The lead-free solder bump's shear strength is better than lead solder and varies irregularly with aging time.

• Journal of Power System Engineering
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• v.17 no.3
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• pp.28-34
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• 2013

This study is experimentally performed for using the oyster shell as a desiccant in the fluidized bed with bundle of heating pipe. The test material is oyster shell from fishery wastes which can use without costs. The main parameters of experiment are inlet air temperature, velocity of inlet air and heat flux of heating pipes. Also the geometry of heating pipe is treated as important parameter. From this study, the effect of inlet air temperature and input heat flux have much affect to increase the heat and mass transfer. On the other hand, the effect of inlet air velocity has less affect to increase the heat and mass transfer. And it is clarified that the oyster shell has sufficient probability for using as a desiccant in air-conditioning system.