• 공업화학
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• 제22권2호
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• pp.155-160
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• 2011

동물성유지는 식물성유지에 비해 산화안정성이 뛰어나며, 높은 발열량과 세탄가를 보여 불완전 연소율이 낮다는 장점을 가지고 있으나 포화지방산의 함량이 높고, 원료유지에 불순물 함량이 높아 정제과정이 필요하다는 단점을 가지고 있다. 본 연구에서는 동물성 유지로 폐돈지를 선정하여 초음파에너지를 이용한 전이에스테르화반응의 최적조건을 설정하고자 하였다. 또한 기존공정의 가열 및 교반을 대체할 수 있는 초음파에너지 효과를 확인함으로써 새로운 바이오디젤 제조공정을 제시하고자 하였다. 기존가열방식을 이용한 폐돈지의 전이에스테르화 반응은 $55^{\circ}C$에서 메탄올과 돈지의 반응몰비 12에서 1 h 반응한 경우 가장 우수한 전환특성을 나타내었다. 전이에스테르화 반응에 초음파에너지를 조사할 경우 최적 초음파 조사세기 500 W에서 반응시간을 30 min으로 크게 단축할 수 있었다. 또한 제조된 바이오디젤의 성능평가 결과 점도는 $0{\sim}70^{\circ}C$ 범위에서 1.3~4.0 cP, 발열량은 40.3 MJ/kg으로 바이오디젤 성능기준을 만족하였다.

• 에너지공학
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• 제21권1호
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• pp.109-117
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• 2012

기후산업은 세계기후변화협약에 대응할 수 있는 산업으로서 기후변화를 창출하거나 이에 대응하는 모든 산업군으로 정의될 수 있다. 본 논문은 그중 신재생에너지산업에 한정하여, 2011년 한국은행에서 발표한 2009년 산업연관표를 활용하여 경제적 파급효과를 분석하였다. 분석의 결과, 2009년 현재 한국 신재생에너지산업은 1원의 생산량 증가를 통해 1.1644원의 생산을 유발하였으며, 0.3544원의 부가가치를 유발한 것으로 분석된다. 취업유발효과는 10억원의 생산량 증가를 통해 10.065명의 취업을 유발한 것으로 분석된다. 그리고 산업구조 전체 속에서 신재생에너지산업의 상대적 위치를 설정하는 산업연쇄효과는 아직 크지 않은 것으로 나타났다. 향후 신성장동력으로 지정한 신재생에너지산업을 활성화하기 위해서는 부가가치를 제고하기 위한 정책이 더욱 활발하게 추진되고, 신재생에너지산업의 부가가치사슬망(value-chain)에 관련된 산업들에 대한 정책도 함께 마련되어야 할 것으로 판단된다.

• 설비공학논문집
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• 제30권4호
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• pp.159-166
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• 2018

The Korean fenestration energy consumption efficiency rating system only considers thermal performance of the heat transfer coefficient (U-value) and airtightness excluding optical characteristics of the solar heat gain coefficient (SHGC). This study analyzed annual heating and cooling energy requirements on the middle floor of apartment by optical and thermal performance of windows to evaluate the suitability of the rating system. One hundred and twenty-eight windows were analyzed using THERM and WINDOW 7.4, and energy simulation for a reference model of an apartment house facing south was performed using TRNSYS 17. The results showed that window performance was the main factor in the heating and cooling load. The heating load of the reference model was 539 kWh to 2,022 kW, and the cooling load was 376 kWh to 1,443 kWh. The coefficient of determination ($R^2$) of the heating and cooling loads driven from the SHGC were 0.7437 and 0.9869, which are more compatible than those from the U-value, 0.0558 and 0.4781. Therefore, it is not reasonable to evaluate the energy performance of windows using only the U-value, and the Korean fenestration energy consumption efficiency rating system requires a new evaluation standard, including SHGC.

• 에너지공학
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• 제21권3호
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• pp.301-308
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• 2012

본 논문은 수송용 LPG 수요함수를 추정하고 장 단기 가격 및 소득탄력성을 분석한다. 또한 추정된 장기 가격탄력성을 활용하여 수송용 LPG 소비로 발생하는 소비자 잉여 및 경제적 편익을 추정한다. 분석에 사용된 가격 및 소득 자료는 각각 2003년부터 2012년까지의 소비자 물가지수로 조정한 월별 실질 수송용 LPG 가격과 월별 경기종합지수이다. 수요함수의 추정을 위해 단위근 검정, 공적분 검정, 오차수정모형 추정의 절차를 취했다. 수송용 LPG 수요는 가격에 비탄력적인 것으로 판단되며 단기보다는 장기가 보다 탄력적이다. 수송용 LPG 수요의 장기 가격탄력성은 -0.422였으며, 이를 이용하여 계산된 수송용 LPG 소비의 소비자 잉여와 경제적 가치는 2012년 3월의 경우 각각 9,660억원 및 1조 7,813억원에 달한다.

• 태양에너지
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• 제13권1호
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• pp.59-66
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• 1993

1990년 12월부터 전국 주요 16개지역에 측정네트�p을 구성하고, 직달일사량 자료를 수집하였다. 측정 된 자료를 토대로 지역별 표준치 설정하여 이들 자료를 집광식시스템의 설계자와 관련 연구자들에게 광범위하게 이용될 수 있도록 제시하였다. 현지 측정사업의 내용을 중심으로 지금까지의 결과를 살펴보면, 1) 우리나라의 법선면 직달일사조건은 청명한 날을 기준으로 하루에 $4,400kcal/m^2$내외이다. 2) 연평균치에 대한 계절별 일사조건은 봄과 여름이 각각 6%, 14% 높았으며, 가을과 겨울은 5%, 15% 정도 상대적으로 낮았다.

• 한국태양에너지학회 논문집
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• 제36권1호
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• pp.39-47
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• 2016

Geographic information system (GIS) based renewable energy resource map including potential analysis can play a crucial role not only to develop the national plan for renewable energy deployment but also to make strategic investment decision in the private sector. Korea Institute of Energy Research (KIER) has been developing domestic maps about several resources such as solar, wind, hydro, biomass, and geothermal, as well as conducting research on methodologies for potential analysis. Furthermore, the institute is trying to transfer related technologies and know-how to foreign countries, recently. In this context, the main purpose of this study is to introduce the business model of renewable energy resource map. From the value chain analysis, we focus on the government-side market in foreign countries, such as the development of the national level renewable energy resource map and the support of the national renewable energy plan. For about 180 countries, we segment the customers according to the consideration of economic capacity, renewable energy resource capacity, existence of renewable resource map, current portion of renewable energy facility capacity, and renewable energy policies, and we conclude that the target customers are non-Organization for Economic Co-operation and Development (non-OECD) countries or some OECD countries, their per capita GDP are under the average among OECD countries, that do not have renewable resource map yet. We segment the target customers into four groups, and suggest different strategies for market positioning and financing strategy based on Strengths, Weaknesses, Opportunities, Threats (SWOT) analysis. This study can help to develop the business strategy about the development of renewable energy resource map in foreign countries.

• 한국수소및신에너지학회논문집
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• 제21권3호
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• pp.184-192
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• 2010

PEM fuel cell produces electric power, water and heat by the electrochemical reaction of hydrogen and oxygen. The heating value is dependent on the molar enthalpy of vaporization of product water and the performance loss. In this paper, the heating value of fuel cell stack has been studied under various stack operating temperatures to achieve more efficient heat management. A technology using the molar enthalpy of vaporization of product water is suggested to reduce heat-up time during start-up of a fuel cell vehicle.

• 한국건축시공학회지
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• 제8권3호
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• pp.111-117
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• 2008

This study provides the setting time prediction method of super retarding concrete incorporating mineral admixtures at the same time including fly ash(FA), blast furnace slag(BS) based on maturity method. The setting time was retarded, as super retarding agent contents increase and curing temperature decreases. In addition, apparent activation energy by Arrhenius function was ranged from $24{\sim}35KJ/mol$ with slightly difference along with mixture proportion. This value is smaller than existing value $30{\sim}50KJ/mol$. It is Indicated that equivalent age using setting time can be a proper method to predict setting time and it also exhibited comparable relativity between prediction value and measurement value. Therefore, this study provided setting time prediction value with super retarding agent contents and mineral admixture combination. Setting time prediction equation provided herein is possibly valid for estimating precise setting time of the super retarding concrete at the job site.

• 한국건축시공학회지
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• 제8권5호
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• pp.119-125
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• 2008

In this paper, the estimation of super retarding concrete incorporating mineral admixtures at the same time including fly ash(FA), blast furnace slag(BS) are studied based on maturity method. The setting time was retarded, as super retarding agent contents increase and curing temperature decreases. In addition, apparent activation energy by Arrhenius function was ranged from $24\sim35$ KJ/mol with slightly difference along with mixture proportion. This value is smaller than existing value $30\sim50$ KJ/mol. Based on strength development estimation. it exhibited comparable relativity between prediction value and measurement value. Therefore, this study provided effective strength development prediction value with super retarding agent contents and mineral admixture combination. Strength development prediction equation provided herein is possibly valid for estimating accurate strength development of the super retarding concrete at the job site.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.367-370
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• 2015

Building deterioration reflects the degradation of basic building performance including structural performance, energy performance, durability, and safety, and it also includes perceived deterioration, which considers a user-based perspective. More than 50% of the existing buildings in Korea are over 15 years old and public buildings compose 2.5% of all buildings domestically. Therefore, there are several different problems, such as poor energy efficiency, structural performance, and safety. To address the challenges of increasing stock in deteriorated buildings, it is necessary to make decisions about reconstruction or renovation. In this study, we propose a new method to evaluate public building value with a contingent valuation method (CVM). By estimating willing-to-pay (WTP) from users of private buildings in similar situation with the public building, it is possible to compare market prices and calculate a correction factor to adjust the WTP data. Finally, we apply the correction factor to the WTP of a public building and estimate market price, willingness to pay (WTP). Finally, we apply the correction factor to willing to pay (WTP) of public building and estimate market price.