• 한국태양에너지학회 논문집
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• 제37권5호
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• pp.39-47
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• 2017

In a hot water system using solar energy, solar heat is not simply collected by the heat collecting plate, but by heat exchange between the solar collector (flat or vacuum type) and the hot water storage tank. Therefore, the amount of collected solar energy depends on the hot water usage patterns that determine the temperature of the thermal storage tank. Also, if the temperature of the hot water stored in the storage tank exceeds the dangerous temperature during the summer, the heat must be released for safety. If the temperature of the hot water in the storage tank is low, it is necessary to heat by the auxiliary heat source. In this study, three buildings are defined as hotel, swimming pool, and school facilities. And we calculated the released heat energy, auxiliary heat source, and pure storage heat energy based on different hot water usage patterns and installation angle of the solar collectors.

• 에너지공학
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• 제21권4호
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• pp.435-443
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• 2012

세계는 원유재고 감소와 국제 정세의 불안정으로 인해 지속적으로 상승하고 있는 유가와 화석연료 사용으로 인한 환경오염에 관심이 고조되고 있다. 국내의 경우 원유를 100% 수입하고 있으며, 사용되고 있는 에너지의 에너지원 중 97%를 수입에 의존하고 있기 때문에 유가 상승에 따른 영향은 더욱 민감하게 나타난다. 국내에 수입되고 유통되는 에너지의 97% 중 1/3 이상이 사무소나 주거용 난방, 급탕 및 취사용으로 사용되고 있다. 이에 따라 정부는 물론 산업체, 연구소 등에서 사무소 및 주거용 에너지 소비패턴으로 인한 경제적인 부담을 줄이고, 고효율 저에너지 기술개발을 통해 소비에너지를 절약함과 동시에 탄소배출을 억제하는 신기술에 대한 연구가 활발하게 이루어지고 있다. 우리나라는 국토가 좁은 반면 인구밀도가 높고, 인구의 도시집중화로 공동주택의 주거비율이 높은 추세이기 때문에 최근 공동주택단지는 초고층화, 대형화가 되고 있으며, 이로 인해 급수 급탕에 대한 사용패턴도 변화하고 있다. 하지만 현재 급수 급탕에 대한 설계 자료는 대부분 외국의 설계 기준과 현장 경험치에 의해 산출된 데이터에 의존하고 있으며, 사용실태에 대한 기초자료가 부족한 실정이며, 이로 인해 급수 급탕 설비 설계 시 과대 또는 과소 설계가 되는 문제가 발생하고 있다. 본 연구에서는 공동주택의 공급자 측 급탕 열 공급환경과 사용자측 열사용량을 측정하여, 급탕부하가 발생하는 시간과 사용 실태 및 패턴을 파악함으로써, 효율적인 공급자 측 급탕설비 설계와 관리를 위한 기초자료를 제시하고자 한다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.156-161
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• 2004

The application of solar energy, in the field of alternative energy, was on the increase tendency. In the case of advanced nations, through continuous R&D, solar hot water heater with high efficiency has been used for the house and the industrial process on business, advanced nations were reached up the experimental stage of solar generation system. But, the actual circumstance of the domestic has been not accomplished the popularization of solar hot water heater and the settlement of it which is the fundamental stage of the solar energy usage. This trouble, the domestic was flooded with small enterprise for producing solar hot water heater, was caused by the popularization and the production without verification of performance. To supply the monitoring program for evaluating solar hot water heater, this research was purpose to improve the technical development of the enterprise for producing solar-heat hot-water-boiler and served as an aid for the enlargement and the popularization on solar energy.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.260-264
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• 2003

The application of solar energy, in the field of alternative energy, was on the increase tendency. In the case of advanced nations, through continuous R&D, solar-heat hot-water-boiler with high efficiency has been used for the house and the industrial process on business, advanced nations on reached up the experimental stage of solar generation system. But the actual circumstance of the domestic has been not accomplished the popularization of solar-heat hot-water-boiler and the settlement of it which is the fundamental stage of the solar energy usage. This trouble, the domestic was flooded with small enterprise for producing solar-heat hot-water-boiler, was caused by the popularization and the production without verification of performance. To supply the monitoring program for evaluating solar-heat hot-water-boiler, this research was purpose to improve the technical development of the enterprise for producing solar-heat hot-water-boiler and served as an aid f3r the enlargement and the popularization on solar energy.

• 한국태양에너지학회 논문집
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• 제26권2호
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• pp.103-109
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• 2006

The Purpose of this work is to investigate a long-term thermal performance of active solar hot water heating system for the dormitory of university. For this, monitering system including temperature sensors, flow-meters was installed in this system. Measurement was continued for 13 months between April 1st 2004 and May 31th 2005. As results, hot water demand, daily and monthly hot water load distribution which are necessary for the solar system design were suggested. Also thermal stratification in solar buffer tank was observed in the point of increasement of system efficiency. The yearly solar fraction and system efficiency of this system are about 29.5% and 44.9% respectively.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.417-417
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• 2009

The application of solar energy, in the field of alternative energy, was on the increase tendency. In the case of advanced nations, through continuous R&D, solar hot water heater with high efficiency has been used for the house and the industrial process on business, advanced nations were reached up the experimental stage of solar generation system. But, the actual circumstance of the domestic has been not accomplished the popularization of solar hot water heater and the settlement of it which is the fundamental stage of the solar energy usage. This trouble, the domestic was flooded with small enterprise for producing solar hot water heater, was caused by the popularization and the production without verification of performance. To supply the monitoring program for evaluating solar hot water heater, this research was purpose to improve the technical development of the enterprise for producing solar-heat hot-water-boiler and served as an aid for the enlargement and the popularization on solar energy.

• 설비공학논문집
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• 제28권9호
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• pp.355-360
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• 2016

Continuing to the modeling of heating load, this paper, as the second part of consecutive works, presents LS-SVM (least square support vector machine) based model of winter time apartment hot water supply load in a district heating system, so as to be used in prediction of heating energy usage. Similar, but more severely, to heating load, hot water supply load varies in highly nonlinear manner. Such nonlinearity makes analytical model of it hardly exist in the literatures. LS-SVM is known as a good modeling tool for the system, especially for the nonlinear system depended by many independent factors. We collect 26,208 data of hot water supply load over a 13-week period in winter time, from 12 heat exchangers in seven different apartments. Then part of the collected data were used to construct LS-SVM based model and the rest of those were used to test the formed model accuracy. In modeling, we first constructed the model of district heating system's hot water supply load, using the unit heating area's hot water supply load of seven apartments. Such model will be used to estimate the total hot water supply load of which the district heating system needs to provide. Then the individual apartment hot water supply load model is also formed, which can be used to predict and to control the energy consumption of the individual apartment. The results obtained show that the total hot water supply load, which will be provided by the district heating system in winter time, can be predicted within 10% in MAPE (mean absolute percentage error). Also the individual apartment models can predict the individual apartment energy consumption for hot water supply load within 10% ~ 20% in MAPE.

• 한국태양에너지학회 논문집
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• 제27권3호
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• pp.45-54
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• 2007

For a conventional natural-circulation type solar water heater, the pressure head is limited by the height between the storage tank and hot water tap. Therefore, it is difficult to provide sufficient hot water flow rate for general usage. This study deals with a design modification of the storage tank to utilize the tap-water pressure to increase hot-water supply Based on fluid dynamic and heat transfer theories, a series of modeling and simulation is conducted to achieve practical design requirements. An experimental setup is built and tested and the results are compared with theoretical simulation model. The storage tank capacity is 240 l and the outer diameter of piping was 15 mm. Number of tube turns tested are 5, 10, and 15. Starting with initial storage tank temperature of $80^{\circ}C$, the temperature variation of the supply hot water is investigated against time, while maintaining minimum flow rate of 10 1/min. Typical results show that the hot water supply of minimum $30^{\circ}C$ can be maintained for 34 min with tap-water supply pressure of 2.5 atm, The relative errors between modeling and experiments coincide well within 10% in most cases.

• 한국자동차공학회논문집
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• 제18권5호
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• pp.25-30
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• 2010

The authors have studied on the corrosion resistance of the hot stamped steel sheets for the application to automotive parts. Recently automotive companies have focused on the hot stamped parts to meet the light weighting needs and the safe reason. Because of the cost reduction of the hot stamped parts, automotive companies increase the usage of the coated steel sheets, especially Al-Si coated steel sheets. The coated layer of Al-Si coated steel sheets contains up to 50% of Fe, which was diffused from the steel sheet, after hot stamping. The hot stamped steel sheet was not phosphated due to the oxidation layer of the coating, however, the result of the water resistance test is similar to that of the conventional GA steel sheets. The pitting depth and the weight reduction of the coated layer of hot stamped steel sheets are less than those of GA steel.

• 대한기계학회논문집
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• 제8권6호
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• pp.517-525
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• 1984

본 연구에서는 2개의 축적탱크와 외부 열교환기로 구성된 가정용 태양열 급탕 시스템을 시뮬레이션 모델로 이론적인 해석을 하고 설계인자들의 값들을 변화시킴으로 써 각각의 성능을 계산할 수 있었다. 또 이 성능 계산치에 의하여 최적설계 인자치 들을 구할 수 있었다. 또한 1983년 1년간 서울지방의 매 시간 일분량과 기온을 사용 하였다.