• 한국물환경학회지
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• 제36권6호
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• pp.535-545
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• 2020

This study aims to conserve and monitor energy use in public sewage treatment plants by utilizing data from the SCADA system and by controlling the aeration rate required for maintaining effluent water quality. Power consumption in the sewage treatment process was predicted using the equipment's uptime, efficiency, and inherent power consumption. The predicted energy consumption was calibrated by measured data. Additionally, energy efficiency indicators were proposed based on statistical data for energy use, capacity, and effluent quality. In one case study, a sewage treatment plant operated via the SBR process used ~30% of energy consumed in maintaining the bioreactors and treated water tanks (included decanting pump and cleaning systems). Energy consumption analysis with the K-ECO Tool-kit was conducted for unit processing. The results showed that about 58.7% of total energy consumed was used in the preliminary and biological treatment rotating equipment such as the blower and pump. In addition, the energy consumption rate was higher to the order of 19.2% in the phosphorus removal process, 16.0% during sludge treatment, and 6.1% during disinfection and discharge. In terms of equipment energy usage, feeding and decanting pumps accounted for 40% of total energy consumed following 27% for blowers. By controlling the aeration rate based on the proposed feedback control system, the DO concentration was reduced by 56% compared pre-controls and the aeration amount decreased by 28%. The overall power consumption of the plant was reduced by 6% via aeration control.

• Journal of Advanced Marine Engineering and Technology
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• 제31권5호
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• pp.592-598
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• 2007

The fuel charge is getting higher in navigation cost. Therefore, shipowners try to find the method for reducing oil consumption. ESS(Energy Saving System) is one of he method. ESS is the system consisted with two inverters, ESS control unit and monitoring system. Two inverters control two main sea water cooling pumps. In the ESS control Unit, the control algorithm finds optimized point to decrease a power consumption of main sea water cooling pumps. Monitoring system observes ESS not to work improperly. ESS is experimented in the laboratory with real condition and analyzed in every view. After experiment, the result of the experiment shows that the control algorithm works correctly and safely. ESS has a plan to be operated in the ship soon. In that case, additional devices are needed to connect ESS with cooling system of the vessel. So the development of addition device is needed and being studied.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.619-626
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• 2011

In this paper, while electric multiple unit is moving on the rail, the content of measuring and analysing electric power consumption is mentioned. In order to measure the electric power consumption, we developed the power record analysis equipment and installed it the inside of the converter and inverter system to record the electric power consumption measured by voltage sensor and current sensor. Moving on the rail, we analysed traction power used up and regenerative power by using the measuring instrument. We expect that the measured and analysed data will offer basic research material to devise a energy reduction plan and introduce a new EMU system with high efficiency.

• Ocean and Polar Research
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• 제40권4호
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• pp.271-280
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• 2018

The purpose of this study is to examine the causal relationship among oil consumption, oil-tanker accidents, and economic growth, and to derive policy implications from the results. Therefore, this paper attempts to analyze the short term, long term, and strong causality factors pertaining to the relationship between oil consumption, oil-tanker accidents, and economic growth in Korea using time-series techniques and annual data for the 1984-2016 period. Tests for unit roots, co-integration, and Granger-causality based on an error-correction model are presented. The results show that bidirectional causality exists between oil consumption and oil-tanker accidents, between economic growth and oil consumption, and between oil-tanker accidents and economic growth. The study shows that oil was used as a core energy source during the rapid economic growth of Korea in the past, and that this caused the number of oil-tanker accidents to rise as oil consumption increased.

• 한국지열·수열에너지학회논문집
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• 제12권4호
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• pp.15-20
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• 2016

Even though the control device of the heating system works well, insufficient water flow rates can degrade control performance and thermal comfort. The water flow rate should be adjusted appropriately to cope with the heating load of each zone. In order to solve these problems, a new balancing concept 'dynamic balancing' was proposed where a balancing valve opening can be automatically modulated according to the heating condition of the room. This study analyzed the effects of dynamic balancing upon indoor thermal environment and energy consumption in a radiant floor heating system through field measurement. Under part-load conditions, the use of a dynamic balancing is a more effective method to reduce energy consumption and to prevent a cavitation. Dynamic balancing is able to help boost the temperature of a room in the start-up period.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권12호
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• pp.3071-3095
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• 2013

Configuring optimization of wireless sensor networks, which can improve the network performance such as utilization efficiency and network lifetime with minimal energy, has received considerable attention in recent years. In this paper, a cross layer optimal approach is proposed for multi-source linear network and grid network under Rayleigh block-fading channels, which not only achieves an optimal utility but also guarantees the end-to-end reliability. Specifically, in this paper, we first strictly present the optimization method for optimal nodal number $N^*$, nodal placement $d^*$ and nodal transmission structure $p^*$ under constraints of minimum total energy consumption and minimum unit data transmitting energy consumption. Then, based on the facts that nodal energy consumption is higher for those nodes near the sink and those nodes far from the sink may have remaining energy, a cross layer optimal design is proposed to achieve balanced network energy consumption. The design adopts lower reliability requirement and shorter transmission distance for nodes near the sink, and adopts higher reliability requirement and farther transmission distance for nodes far from the sink, the solvability conditions is given as well. In the end, both the theoretical analysis and experimental results for performance evaluation show that the optimal design indeed can improve the network lifetime by 20-50%, network utility by 20% and guarantee desire level of reliability.

• 대한설비공학회지:설비저널
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• 제17권4호
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• pp.442-447
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• 1988

To keep comfortable indoor condition, the existing air conditioning system is controlled by the ON/OFF temperature controller. The PID control unit is developed to control temperature and humidity simultaneously, and the Air-conditioning control system is transferred from the ON/OFF temperature controller to the PID control unit for experiment. As a result of this experiment, the PID control unit reduced energy consumption compared with the ON/OFF control unit.

• 한국환경과학회지
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• 제23권9호
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• pp.1643-1654
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• 2014

The university is one of the main energy consumption facilities and thereby releases a large amount of greenhouse gas (GHG). Accordingly, efforts for reducing energy consumption and GHG have been established in many local as well as international universities. However, it has been limited to energy consumption and GHG, and has not included air pollution (AP). Therefore, we estimated GHG and AP integrated emissions from the energy consumed by Seoul National University of Science and Technology during the years between 2010 and 2012. In addition, the effect of alternative energy use scenario was analysed. We estimated GHG using IPCC guideline and Guidelines for Local Government Greenhouse Inventories, and AP using APEMEP/EEA Emission Inventory Guidebook 2013 and Air Pollutants Calculation Manual. The estimated annual average GHG emission was $11,420tonCO_{2eq}$, of which 27% was direct emissions from fuel combustion sectors, including stationary and mobile source, and the remaining 73% was indirect emissions from purchased electricity and purchased water supply. The estimated annual average AP emission was 7,757 kgAP, of which the total amount was from direct emissions only. The annual GHG emissions from city gas and purchased electricity usage per unit area ($m^2$) of the university buildings were estimated as $15.4kgCO_{2eq}/m^2$ and $42.4tonCO_{2eq}/m^2$ and those per person enrolled in the university were $210kgCO_{2eq}$/capita and $577kgCO_{2eq}$/capita. Alternative energy use scenarios revealed that the use of all alternative energy sources including solar energy, electric car and rain water reuse applicable to the university could reduce as much as 9.4% of the annual GHG and 34% of AP integrated emissions, saving approximately 400 million won per year, corresponding to 14% of the university energy budget.

• 사물인터넷융복합논문지
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• 제7권3호
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• pp.9-14
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• 2021

본 논문에서는 주택이나 건물의 단열 진단을 통하여 에너지 손실 요인을 발견하고 이에 따른 에너지 효율 개선에 대한 방향을 제시하고 있다. 건축물의 에너지 효율 요소는 단열 진단, 열교 진단, 창호 진단, 기밀 진단, 설비 진단 등으로 구성된다. 에너지 복지 사각지대 주민 및 시설 중 전라남도 나주시에 위치한 한 경로당 건물을 대상으로 하여 에너지 효율 진단을 실시하고 단열 시공을 한 후의 에너지 효율 진단을 실시하였다. 에너지 측정과 진단 및 분석은 IoT 기반 통합 유무선 에너지 진단 플랫폼인 에너지 파인더를 이용하였다. 비교 결과 전체적으로 16.38%의 에너지 절감률을 달성하였다. 연간 단위 면적당 난방 에너지 소요량은 시공 전 333.51kWh에서 시공 후 277.35kWh로 감소되었고, 연간 단위 면적당 냉방 에너지 소요량은 시공 전 5.51kWh에서 시공 후 5.22kWh로 감소되었다. 연간 단위 면적당 1차 에너지 소요량은 시공 전 464.52kWh 였으나 시공 후 403.69kWh로 감소되었으며, 연간 에너지 사용 비용은 시공 전 3,063,307.14원이었으나 시공 후 2,641,072.49원으로 절감되었다. 단열 이외의 에너지 효율에 영향을 미치는 기준들에 대한 추가적인 개선 작업이 필요하다고 판단된다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.1185-1190
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• 2009

Korea is an industrial country that overspends energy and has a policy that is more focused on a supply side. When an urban developmental program is to set up, surveys are carried out only with the respect to electricity, telecommunication, gas, and heating sources. Based on the existing survey results, the problems related to the supply side are being dealt with more importantly and the quantities of those supplies are estimated only by each energy source. The aim of this study is to provide basic information on energy consumption patterns of a diverse comsumer groups including industry, transportation, commerce, public and household to plan diverse energy policies. Through this basic information, it may be possible to analyze the energy consumption pattern by each consumer group and provide data for setting up efficient energy policies by the government. The energy consumption map that are analyzed and developed by the data obtained from Busan municipal area will be deposited and used as a part of the national energy statistics.