• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.106-111
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• 2001

This paper is a study on the heat generation characteristics of the carbon heating source with high temperature. The main variables of this study are the input current and the amount of carbon heating source. As the results of the experiment in the waste rate of carbon heating source. The case of carbon heating source 300g was large than 500g. As the input current and the temperature are increased, the resistance values of carbon heating source were large. The Joule heat was represented the large value as the amount of heating source decrease with the input current. Finally, the heating source was represented the electrical steady state as the input current is increase.

• 한국지반환경공학회 논문집
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• 제8권3호
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• pp.11-18
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• 2007

본 연구에서는 파급효과가 큰 공동주택에서 지열 냉난방 시스템의 경제성을 아파트 분양평형, 운전시간, 냉난방 및 급탕 설치형태별로 구분하여 초기 공사비 증가, 운전비 절감액, 초기 투자비 회수기간등을 산정하였다. 냉난방 및 급탕 운전시간이 많을수록 초기 공사비 증가액에 비해 운전비용 절감액이 커 초기 투자비 회수기간이 단축되었다. 전용면적이 클수록 투자회수 기간이 길었으며 냉난방 및 급탕 설치형태에서는 냉난방을 지열원, 급탕을 폐열회수한 경우가 초기 투자 회수기간이 가장 짧았다. 기존 시스템(패키지 에어콘, LNG 난방 및 급탕)에 비해 냉난방, 급탕을 모두 지열로 이용하는 경우, 냉난방은 지열, 급탕은 폐열을 이용하는 경우, 냉난방은 지열, 급탕은 LNG인 경우에 공사비가 $m^2$당 각각 약 72,000원, 66,900원, 62,300원 정도 증가하였다.

• 환경위생공학
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• 제17권2호
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• pp.18-25
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• 2002

The comparison of the air quality with the evaluation of the environmental assessment before and after operations of the heat source and of the flue-gas desulfurization facilities were studied. First of all, several sites were selected for the representative sample points, and then they were examined air quality of the surroundings. The results were that TSP(total suspended particulate) analysis after an operation of the heat source facility was $74~81{\mu}g/m^3$, PM-10 was $31~94{\mu}g/m^3$, and $SO_2$concentration was 0.002~0.009ppm, respectively. As the result of examination to the concentrations of diffused pollutants, there was no relations between TSP concentration of sample points and the effect of air quality according to the heating source. When we compared the neighbored area of the heating source with the other area, the concentration of air pollutants after an operation of the facility of the heating source was similar to the heating source, the neighbored area, and the other area. So we concluded that there was no the effect of the air pollution by producted pollutants from the heating source.

• 동력기계공학회지
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• 제8권1호
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• pp.30-35
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• 2004

This paper represents the numerical analysis on effect of the environmental velocity for circular heating source with heat generation. In general heating system, the oil and sheath heater is widely used, but these systems have many problems. So, the heating source with carbon ingredient has been researched in many country about manufacture, thermal and electrical properties. In this research, a circular heating source was studied through numerical analysis on several conditions of unsteady state, beat generation and environmental velocity. The temperature distributions at steady state is appeared as a non-linear pattern with variations of environmental velocity. So, the correlation equation between temperature at steady state and environmental velocity was obtained.

• 한국지열·수열에너지학회논문집
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• 제8권2호
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• pp.9-15
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• 2012

The objective of this study is to investigate the influence on the heating performance for a water-to-water 10RT ground source heat pump by using the water switching and refrigerant switching method. The test of water-to-water ground source heat pump was measured by varying the compressor speed, load side inlet temperature, and ground heat source side temperature. The heating capacity and COP of the heat pump increased with increasing ground heat source temperature. As a result, compared to a refrigerant switching method, the water switching method with counter flow improves the heating capacity and COP by approximately 5% in average, respectively.

• 전기학회논문지
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• 제67권12호
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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.

• 동력기계공학회지
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• 제7권4호
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• pp.31-37
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• 2003

This paper is a study on application of warm air circulator by using the carbon heating element with particle type. The main variables are the input current and amount of carbon heating source for experimental characteristics. The experimental results are obtained as follows. As the input current and temperature are increased, the resistance of heat source is decreased about $20{\sim}25%$ by the effect of negative resistance. As the amount of heating source is small, Joule heat is large with the input current. When the amount of heating source is 300 and the input current is 15A, the value of Joule heat is about 4604.6kJ/h. The heat production efficiency of carbon heating source is larger about 10% than the sheath heater.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.169.2-169.2
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• 2010

The research assesses the performance of the water-to-water heat pump system installed in Cheongju water treatment plant for cooling and heating ventilation. In summer season monthly averaged COP is ranged from 3.85 to 4.56 according to the water source temperature, and the performance is increased as the raw water temperature is dropped. While, heating performance is increased for the high temperature water source, and the monthly averaged COP is changed from 2.92 to 3.82. The correlation of the water source temperature and the heat pump performance shows a linear tendency by the simple regression of average data. In heating, the COP of heat pump system linearly rises according to the water source temperature. In comparison, the COP in cooling linearly reduces as the raw water temperature is raised. The goodness of fit at the simple regression shows the coefficient of determination 82% in cooling, 46% in heating. The electric cost of water-to-water heat pump is reduced by 40% compared to that of air source heat pump.

• Journal of Advanced Marine Engineering and Technology
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• 제34권5호
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• pp.617-624
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• 2010

선박 건조공정에서 외피의 곡면 가공에 많이 사용하는 가공법을 선상가열법이라고 한다. 선상가열법은 엔지니어의 숙련도에 따라 품질의 차이가 커지기 때문에 현재에는 엔지니어의 숙련도에 의존하지 않는 자동화기기를 사용하여 선상가열을 수행하는 경우가 많다. 본 연구에서는 자동화기기를 사용한 선상가열에 의한 가열판재의 온도분포를 조사하고자 한다. 선상가열시 적용되는 주요한 변수는 가열원의 이동속도, 강도 및 가열 방식 등이 있으며, 본 연구에서는 세 가지 변수를 중심으로 가열판재의 표면 및 내부온도가 어떻게 변화하는지를 조사하였다. 해석결과 가열원의 이동속도가 빨라질수록 판재의 피크온도는 낮게 형성되는 것을 확인하였고, 또한 열원의 크기에 따른 피크온도 및 온도분포가 선형적으로 변화하는 것을 정량적으로 계산할 수 있었다.

• 설비공학논문집
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• 제26권5호
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• pp.218-223
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• 2014

Korea District heating corp. recently give an attention to combine the district heating and supply pipes as a two pipe system that are in the present system separated with room heating and warm water supply pipe, and the two pipe system is commonly applied for heating service in European countries. In the new two pipe system, only one heat source is supplied to a house and partitioned into room heating and warm water supply by household substation. So the effective distribution of supplied heat source in accordance to user intention is very important. This paper presents the development and performance test of three-way proportional control valve for a combined heat source system in district heating. The proposed valve is controlled to partition heat source into two different directions : hot water distributor for space heating and household substation for warm water supply in response to the pressure drops of tap water caused by the user. The performance investigation is shown within 3% of error compared to the theoretical model of the three-way proportional valve and its controllability is verified.