• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1037-1038
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• 2007

프리피스톤 기관은 크랭크가 없는 엔진을 동력원으로 리니어 발전기를 구동시켜 전기에너지를 생성하는 시스템으로 기존 왕복 구동식 기관에 비해 기계적 손실이 작고, 팽창 에너지를 최대한 활용할 수 있는 고효율 기관으로 평가되고 있다. 또한 프리피스톤 기관은 가솔린, 디젤, 수소, 천연가스와 같은 청정 연료를 사용할 수 있기 때문에, 최근 에너지 수급 문제 및 대체 에너지원으로 활용할 수 있다는 장점을 가지고 있다. 프리피스톤 기관에 적용되는 리니어 발전기의 경우 기존 회전형 발전기보다 효율은 다소 떨어지는 단점은 있으나, 동력 변환을 하지 않는 리니어 엔진에 적용할 경우에는 효율적 이득을 볼 수 있다. 본 논문에서는 리니어 발전기의 성능 측정을 위한 시험 장치를 구성하고, 프리피스톤용 기관에 적용되는 평판형 및 원통형 타입의 리니어 발전기의 손실 및 효율 특성을 비교하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.603-613
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• 2021

As a core policy for achieving the goal of reducing greenhouse gas emissions in the building sector, Korea has enforced the mandatory certification of zero energy buildings for new public buildings from 2020. This study suggests energy-saving technologies and economic factors that building officials can refer to for decision-making on the implementation of zero energy buildings. For this study, the construction cost for the energy item of a building was analyzed by collecting the building energy efficiency level certification data and detailed construction cost statement data from public institutions for the last three years. Based on the building energy efficiency certification data, each energy item of the baseline building was derived, and the energy performance of the zero energy building was derived through repetitive simulations by gradually increasing the energy performance value of the baseline building. By applying the analyzed construction cost, the construction cost for each energy item of the baseline and zero energy buildings was derived. As a result, the lighting equipment contributed up to 10.5% energy savings, and the increase in construction cost of the cooling and heating system was at least 9.1%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.7
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• pp.571-579
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• 2013

This paper proposes an energy-efficient mode selection and power allocation scheme in device-to-device (D2D) communication system as an underlay coexistence with cellular networks. We analyze the energy efficiency which is defined as the summation of the energy efficiencies for all devices. The proposed scheme consists of two steps. First, we calculate the transmission power maximizing the energy efficiency for all possible modes of each device. Although the proposed power cannot maximize the system capacity, we prove that the proposed transmission power is the optimal power which maximizes the energy efficiency. In the second step, we select a mode which has the maximal energy efficiency among all possible mode combinations of the devices. Then we can jointly obtain the transmission power and the mode which can maximize the energy efficiency. The proposed scheme has the optimal performance with respect to the energy efficiency and outperforms the conventional schemes.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.103-106
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• 2008

신재생에너지기술 개발인력 확보는 국가 에너지 안보의 확보 및 지속적인 성장을 가능하게 하는 주요 요인이다. 관련 사업추진에 있어 비효율성의 제거와 인적자원 개발 정책의 효과적인 추진을 위해서 신재생에너지 인력양성 사업에 대한 체계적인 성과평가가 요구되고 있다. 본 연구에서는 신재생에너지 인력양성의 평가를 위하여 적용가능한 방법론을 살펴 보았다. 기존 인력양성 방법론의 구분을 수정하여 인력 양성의 평가 방법을 성과점검, 요인통제분석, 사업의 파급효과 산출방법으로 분류하고 각 기준별 세부방법론을 제안하였다. 성과점검 방식에는 단순환산/일반질문법, 요인통제분석에는 AHP-DEA효율성 측정방법, 인적자본 축적모형방법이 포함될 수 있다. 마지막으로 사업의 파급효과 산출방법에는 산업연관분석 방법, 인력양성 산업연관도 작성 방법이 있다. 제안된 모형 중AHP-DEA효율성 측정방법은 신재생 에너지 인력양성 평가에 적용될 경우 DEA 모형의 객관성이라는 특징을 최대한 이용하는 동시에, 한계로 지적될 수 있는 변별력 분제를 체계적으로 보완하기위한 방편으로 AHP를 도입함으로써 적절한 인력양성 평가 방법론으로 적용될 수 있을 것이다.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.165.2-165.2
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• 2010

The objective of this study is to analyze the energy saving rate by retrofitting multi air conditioner from conventional type to high efficient type using Energyplus 4.0 which was developed for simulating a building energy by D.O.E. Generally, Multi air conditioner system was installed for both the cooling and the heating in a building. However, it was difficult to estimate the energy saving rate in the case of retrofitting multi air conditioner from conventional type to high efficient type. In the present study, annual energy consumptions of them were evaluated for same building and climate condition.

• Textile Coloration and Finishing
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• v.2 no.3
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• pp.59-64
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• 1990

염색가공 공장의 총가공비 가운데 에너지비가 점하는 비율은 약 20∼25%에 달하는 것이 일반적이다. 따라서 省에너지가 염색가공에 있어서 중요한 과제가 되고 있으며 소비되어지는 에저지로서는 전력에너지는 비교적 적고 熱에너지가 많으므로 열에너지 적감 효율이 높은 Kusters사에서 제작한 연속 염색기에 대해 조사한 바를 아래에 보고하고져 한다.

• Journal of Internet Computing and Services
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• v.9 no.5
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• pp.131-140
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• 2008

In this paper, we present a data dissemination protocol that guarantees energy-efficient data transmission and maximizes network lifetime. SPMS that outperforms the well-known protocol SPIN uses the shortest path to minimize the energy consumption. However, since it repeatedly uses the same path, maximizing the network lifetime is impossible. In this paper, we propose a protocol for data dissemination called the protocol Considering Between Energy and Distance (ConBED). It solves the network lifetime problem using the residual energy and the distance between nodes to determine a path for data dissemination. The simulation results show that ConBED guarantees energy-efficient transmission and increases the network lifetime by approximately 69% than that of SPMS.

• Land and Housing Review
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• v.6 no.4
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• pp.215-220
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• 2015

The purpose of this study was to comparative analyses of energy performance in apartment houses adopted window frame-type natural ventilation, under-floor air distribution ventilation and heat recovery ventilation. As the object of energy simulation, the three type ventilation system with area of $84m^2$ was selected in apartment house. As a result, when the ECO2 simulation was performed, the 1st requirement quantity per annual were $159.9kWh/m^2yr$(CASE1, Natural Ventilation), $179.7kWh/m^2yr$(CASE2, Under-floor Air Distribution Ventilation) and $161.0kWh/m^2yr$(CASE3, Heat Recovery Ventilation).

• Journal of Energy Engineering
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• v.24 no.4
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• pp.97-104
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• 2015

The performance in scientific contribution of renewable energy R&D has been overlooked, as it is shown in terms of industrial aspect. This paper analyzed the R&D efficiency of scientific aspects of each renewable energy resource in 2008-2012. Total R&D fund and the number of supported projects are selected as input variables, and the number of patents and papers as output variables to analyze the direct efficiency using DEA method. Through the analysis, it determines the efficiency of each energy resource R&D, and investigated the causes of inefficiency. This study has meaning to include entire renewable energy sources for the analysis, and is expected to serve as an important reference in policy making.

• Journal of Energy Engineering
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• v.20 no.3
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• pp.178-184
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• 2011

Compressed Air Energy Storage (CAES) is a combination of energy storage and generation by storing compressed air using off-peak power for generation at times of peak demand. In general, both charging and discharging of high-pressure vessel are unsteady processes, where the pressure is varying. These varying conditions result in low efficiencies of compression and expansion. In this paper, a new constant-pressure CAES system to overcome the current problem is proposed. An energy analysis of the system based on the concept of exergy was performed to evaluate the energy density and efficiency of the system in comparison with the conventional CAES system. The new constant-pressure CAES system combined with pumped hydro storage requires the smaller cavern with only half of the storage volume for variable-pressure CAES and has a higher efficiency of system.