• 한국항해항만학회지
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• 제35권3호
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• pp.265-270
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• 2011

본 연구는 건물에너지 효율 향상을 위한 목적으로 기상데이터 변화에 따른 건물 냉 난방부하량을 예측하고 결과를 비교 분석한 것으로, 연구 성과는 다음과 같다. 1)기상청에서 입수데이터를 평가툴인 ESP-r에 활용할 수 있도록 항목별 기상데이터를 개발하였다. 표준기상 데이터의 외기온도, 습도, 풍속은 대부분의 경우 기상청데이터 보다 크거나 높았다. 수평면전일사량은 기상청데이터가 높았고, 직달일사량은 겨울철에는 표준기상데이터가, 여름철에는 기상청데이터가 많은 것으로 나타났다. 2)대학교 캠퍼스 내에 신축된 후생복지관을 대상으로 한 시뮬레이션 결과, 최대난방부하의 경우 표준년도, 2006년, 2009년이 비슷한 반면 2007년은 표준년도 대비 81%, 2008년은 96% 수준이었고, 연간난방부하는 2006년, 2008년의 순으로 난방수요가 많았다. 한편, 냉방부하의 경우에는, 상대적으로 최대냉방부하가 큰 2007년, 2009년의 연간 냉방부하보다 최대냉방부하가 가장 적은 2008년의 연간냉방부하가 더 큰 결과를 보였다. 3)냉 난방기기의 상당시간가동률을 평가한 결과, 표준년도의 최대부하대비 상당시간가동률은 2006~2009년이 표준년도에 비해 대부분 가동률이 낮았다.

• 항공우주기술
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• 제2권2호
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• pp.83-88
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• 2003

발사시 fairing jettison-separation의 과정에서 발사체에 탑재된 위성체가 우주환경에 노출이 되어 태양광, 지구복사, Albedo, free molecular heating 등의 여러 가지 열환경의 직접적인 영향을 받게 된다. 이 때, 위성체 중에서 발사체의 진행 방향으로 최외각에 위치한 payload box가 worst hot condition의 조건을 만족하며 가열되게 된다. Payload box를 하나의 질량으로 가정하고 적용되는 여러 가지 열환경을 고려하여 온도지배방정식을 정리하면 해석해가 존재하는 1차원 미분 방정식을 유도할 수 있다. 이 식으로부터 구한 해석해를 worst hot condition을 만족하는 payload box에 적용하여 발사시 가열에 의한 온도 상승 정도를 예측하고, 그 결과로부터 위성체의 열적 안정성을 비교적 간단한 방법으로 검증할 수 있다.

• 한국수소및신에너지학회논문집
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• 제13권1호
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• pp.83-89
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• 2002

The goal of this research is to understand the NOx emission in direct injected diesel engine with premixed hydrogen fuel. Hydrogen fuel was supplied into the test engine through the intake pipe. Amount of hydrogen-supplemented fuel was 70 % basis on heating value of the total input fuel. The effects of intake air temperature and exhaust gas recirculation(EGR) on NOx emission were studied. The intake air temperatures were varied from $23^{\circ}C$ to $0^{\circ}C$ by using liquid nitrogen. Also, the exhaust gas was recirculated to the intake manifold and the amount of exhaust gas was controlled by the valve. The major conclusions of this work include: ( i ) nitrogen concentrations in the intake pipe were increased by 30% and cylinder gas temperature was decreased by 24% as the intake air temperature were changed from $23^{\circ}C$ to $0^{\circ}C$; ( ii ) NOx emission per unit heating value of supplied fuel was decreased by 45% with same decrease of intake air temperature; and (iii) NOx emission was decreased by 77% with 30% of EGR ratio. Therefore, it may be concluded that EGR is effective method to lower NOx emission in hydrogen fueled engine.

• 한국지열·수열에너지학회논문집
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• 제13권4호
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• pp.31-38
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• 2017

The heating and cooling air conditioning field has been increasing the problems of energy consumption and global warming in the world. A geothermal heat pump has been known as one of the highest efficient heating and cooling system. In this study, the analysis about the test standards of the geothermal heat pump of the Republic of Korea was executed. From the research, the following results were given. It is needed to address the domestic test standard for direct heat exchange geothermal heat pump. Water to air multi geothermal heat pump test standard was only developed in Korea. The test standard to calculate a seasonal energy efficiency ratio for cooling period and heat seasonal performance factor for heating period should be newly developed to estimate actual annual energy consumption and $CO_2$ emission.

• KIEAE Journal
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• 제12권6호
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• pp.29-38
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• 2012

The current building energy efficiency rating certification regulation on apartment houses evaluates only the saving rate of energy consumed during operation, i.e. use, of a building, but doesn't consider the energy consumptions and environmental load($CO_2$) emissions occurring during the whole lifetime of a building. So this study calculated the energy consumptions and environmental load emissions occurring during the whole lifetime of a building, selected reference schemes and alternative items by design variables to present a design draft considering energy efficiency and environmental performance, and evaluated the total cost by combining and calculating its direct cost(material and heating cost) and indirect cost(environmental cost), for an existing apartment house as an evaluation object. As a result of analysis, the change of heating cost by alternative items of design variables showed a 4~8% change rate compared to the reference scheme, and the material cost of design variable 7 showed a maximum 4.4 times change rate in the alternative plan 6 compared to the reference scheme. The environmental cost showed a similar change rate to the material cost change rate in general, but showed a similar environmental cost change rate to the heating cost change rate in case of design variables 4-1, 4-2, 7.

• 한국산업융합학회 논문집
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• 제5권4호
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• pp.379-384
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• 2002

As automotive diesel engines adopt the direct injection method for a lower level of the exhaust emission and a higher fuel efficiency, the maximum temperature of engine coolant decreases. Consequently, the total available heat source from the engine coolant decreases over 35%. However, the heating source of air-conditioning system in automobiles depends on the hot engine coolant completely, so that it is nearly impossible to control air conditioning in heating season. Therefore, the present study has been carried out to develop the air conditioning system for the high efficient heat pump type using the HFC-134a. Especially, the air conditioning system of heating has been developed at a beginning stage, when it has low heat source from small and medium sized diesel recreation vehicles. To develop a control logic system for air conditioning system which is a heat pump type with a heat recovery exchanger, its cycle characteristics has been investigated according to the opening of LEV at a bench system.

• 한국산학기술학회논문지
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• 제20권3호
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• pp.476-482
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• 2019

본 기후변화협약, 온실가스배출규제와 같은 규제적 규약들은 고효율 에너지 기자재 개발과 에너지의 효율적 이용을 촉진하는 촉매로 작용하고 있다. 에너지소비가 큰 분야 중 전열기기가 효율이 좋지 못한 편이다. 전기보일러는 히터에 물을 접촉시켜 순환시키는 방식을 주로 사용하고 있다. 기존 전기보일러를 활용할 경우 물의 미네랄이 고온의 히터와 접촉하여 탄화되어 흡착되는 과정에서 히터의 부식을 촉진시키고 히터의 효율을 저하시킨다. 이러한 이유로 에너지 효율이 높고, 전도나 대류가열보다 피가열물을 균일하게 가열시킬 수 있는 유도가열방식을 보일러에 적용시킨 전기유도보일러가 각광을 받고 있는데, 이 방식은 물이 담겨 있는 보일러 관로를 유도가열방식으로 가열하여 직접가열시 발생하는 문제를 해결시킬 수 있는 대안으로 인정받고 있다. 비교적 오랜 기간 유도가열에 대한 연구가 이루어졌음에도 불구하고 유도가열을 이용한 전열기술에 대한 연구결과는 그리 많지 않은 실정이다. 따라서 본 논문에서는 전기유도보일러의 발열효율을 개선하기 위하여 매개변수연구방법을 통하여 권선의 단면적, 권선의 수 및 권선의 겹수에 의한 영향을 유한요소법을 이용하여 해석하고 발열의 요소가 되고 있는 동손과 철손을 분석하여 발열을 극대화시킬 수 있는 권선설계방법으로 총손실이 최대가 되는 설계점을 찾는 방법을 제시하였다.

• 한국수소및신에너지학회논문집
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• 제28권4호
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• pp.392-400
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• 2017

An experimental study was conducted to investigate behavior of steel surface oxidation with characteristics of the combustion. The excess entalphy combustion in porous media system was applied to implement the direct radiation heating system. The surface oxidation thickness (SOT) of fuel-lean was thicker than the SOT of fuel-rich. Also, the SOT was increased by increasing residence time. Detailed explanations were given by SEM and EDS analysis.

• Environmental Analysis Health and Toxicology
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• 제29권
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• pp.7.1-7.8
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• 2014

Objectives The present study was designed to systematically characterize the denaturation and the renaturation of double stranded DNA (dsDNA), which is suitable for DNA hybridization. Methods A series of physical and chemical denaturation methods were implemented on well-defined 86-bp dsDNA fragment. The degree of each denaturation was measured and the most suitable denaturation method was determined. DNA renaturation tendency was also investigated for the suggested denaturation method. Results Heating, beads mill, and sonication bath did not show any denaturation for 30 minutes. However probe sonication fully denatured DNA in 5 minutes. 1 mol/L sodium hydroxide (alkaline treatment) and 60% dimethyl sulfoxide (DMSO) treatment fully denatured DNA in 2-5 minutes. Conclusions Among all the physical methods applied, the direct probe sonication was the most effective way to denature the DNA fragments. Among chemical methods, 60% DMSO was the most adequate denaturation method since it does not cause full renaturation during DNA hybridization.

• 한국연소학회:학술대회논문집
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• 한국연소학회 1999년도 제19회 KOSCO SYMPOSIUM 논문집
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• pp.105-110
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• 1999

The elementary experiment was performed to develop the emulsified fuel production system using pressure injection nozzle in this study. The stabilities and characteristics of emulsified fuel which is produced through direct spray of water via pressure injection nozzle into oil are examined. To understand performance of emulsion production, stabilities of emulsified fuel which is made by adding water to the mixed fuel of Bunker-C and 10 $^{\sim}$ 50 vol% of heating oil were investigated. According to volume ratios of surfactant in heating oil the stability and SMDs were measured