• 한국태양에너지학회 논문집
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• 제34권5호
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• pp.117-126
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• 2014

This study developed a KRESS program designed to find the optimization ratio for new and renewable energy systems and analyze the effects of building energy consumption characteristics on the ratio. In spite of clear differences in predicted energy consumption and energy consumption by the loads among 18 facilities, the current formula for obligatory supply ratios applies a correction coefficient according to the building purposes based on energy consumption per each unit area in medical facilities and thus reflects no energy consumption characteristics according to the building purposes. The optimization ratio for new and renewable energy systems was the same for all facilities when the correction coefficients by the building purposes and new and renewable energy sources were all applied. When the correction coefficients were not applied, however, the optimization ratio varied according to building energy consumption characteristics. The findings raise a need to test the correction coefficients in order to select new and renewable energy systems that take into account energy consumption characteristics by the building purposes and loads and reflect economy, environmental performance, and technology.

• 한국농촌건축학회논문집
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• 제10권4호
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• pp.57-64
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• 2008

This paper presents the real condition and problems of rural communities, shift of social paradigm, and also discussed the results and efforts of existing energy supporting policy by literature review. The aim of this study is to suggest the new supporting policy of energy saving facilities for rural communities, and to show its necessity, framework, promotion method, and connection plan with existing policy. Based on this study, mainly three results can be drawn as follows; first, this new policy is required that not only suggestive reason such as energy crisis and social atmosphere, but also, financial support and welfare service for resident of rural area. Second, the various rural facilities including residence must be planed sustainable energy saving system by this new policy. And the third, this policy should be simultaneously adopted with rural development policy, and must drive forward that is closely connected with a related policy.

• 한국수소및신에너지학회논문집
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• 제21권4호
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• pp.286-294
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• 2010

According to the propagation of fuel cell system, the importance of that system efficiency is being magnified. Thus, the efficiency improvement of reformer which is the important part of fuel cell system will be required. In structural aspect, the reformer is classified into cylindrical and plate type. Plate type reformer features better maintenance and space efficiency compared with cylindrical type. In this study, we changed the shape of combustion chamber to improve the reforming efficiency. And then we performed the CFD simulation to predict the spacial distribution of temperature. Analysis cased contains with baffles, fins, baffles and fins, and without those. In case of only with-baffle, temperature distributions were uneven because the high temperature stream was concentrated near the baffle end. In case of with-fin, the temperature distributions were relatively even than other cases.

• 설비공학논문집
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• 제25권10호
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• pp.540-547
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• 2013

We experimented with the energy saving effect of applying a multiplex heat pump system and suggests a dissemination plan for new and existing educational facilities. The development and dissemination of a new system could reduce energy consumption by up to 57%, and help solve environmental issues. Experimental performance evaluated in the kindergarten to analyze the energy saving effect of the cooling and heating system. The average daily COP of the cooling and heating period in the field test was 3.79. Our results showed that the annual energy consumption was reduced, and proved that the multiplex heat pump system is effective in reducing energy consumption.

• 한국수소및신에너지학회논문집
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• 제30권4호
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• pp.303-311
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• 2019

Reversible solid oxide fuel cell (RSOFC) has become a prospective device for energy storage and hydrogen production. Many studies have been conducted around the world focusing on system efficiency improvement and realization. The system should have not only high efficiency but also a certain level of simplicity for stable operation. External waste steam utilization was proved to remarkably increase the efficiency at solid oxide electrolysis system. In this study, RSOFC system coupled with waste steam was proposed and optimized in term of simplicity and efficiency. Ejector for fuel recirculation is selected due to its simple design and high stability. Three system configurations using ejector for fuel recirculation were investigated for performance of design condition. In parametric study, the system efficiencies at different current density were analyzed. The system configurations were simulated using validated lumped model in EBSILON(R) program. The system components, balance of plants, were designed to work in both electrolysis and fuel cell modes, and their off-design characteristics were taken into account. The base case calculation shows that, the system with suction pump results in slightly lower efficiency but stack can be operated more stable with same inlet pressure of fuel and air electrode.

• 신재생에너지
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• 제19권4호
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• pp.61-71
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• 2023

The necessity of energy utilization using livestock manure has been proposed with the decrease in domestic agricultural land. Livestock manure solid fuel has been investigated as a promising energy resource owing to its convenient storage and use in agricultural and livestock fields. Additional electricity production is possible through the integration of a biomass combustion boiler with the organic Rankine cycle (ORC). In this study, a mathematical system model of the cattle manure solid fuel boiler integrated with the ORC was developed to analyze the components' performance under variable operating conditions. A sensitivity analysis was conducted to confirm the electrical efficiency of the ORC turbine and the applicability of this system. The minimum required waste heat recovery rate was derived considering the system marginal price and levelized cost of electricity of the ORC. The simulation results showed that, in Korea, more than 77.98% of waste heat recovery and utilization in ORC turbines is required to achieve economic feasibility through ORC application.

• KEPCO Journal on Electric Power and Energy
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• 제4권1호
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• pp.1-7
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• 2018

Objective signs are everywhere that the stationary energy storage market is growing up quickly. The use of distributed resources such as solar photovoltaics and electric vehicles are expanding at a rapid pace, creating technical challenges for the distribution system that will require energy storage and a new generation of software to address. This paper is intended for distribution utility managers and executives and makes the following points: ${\bullet}$ Utility-integrated (as opposed to merely grid-connected) energy storage projects represent a distinct, new wave of industry growth that is just getting underway and is required to manage distributed energy resources moving forward. ${\bullet}$ Utilities and the energy storage industry have important roles to lower risk in adopting this technology - thereby enabling this wave of growth. ${\circ}$ The industry must focus on engineering energy storage for adoption at scale - including the creation and support of software open standards -both to drive down costs and to limit technology and supplier risk for utilities. ${\circ}$ Utilities need to take a program-based, rather than a project- based, approach to this resource to best balance cost and risk as they procure and implement energy storage. By working together to drive down costs and manage risk, utilities and their suppliers can lay the energy storage foundation for a new, more digital distributed electricity system.

• 한국태양에너지학회 논문집
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• 제32권3호
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• pp.153-161
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• 2012

This study conducted a survey and field investigation on the application of the Public Obligation System for new & renewable energy in public buildings, as well as energy consumption of each building according to their uses. The findings are as follows: (1) Since the introduction of the Public Obligation System (until June 30, 2011), there was average 1.4 new & renewable energy facilities established at 1,433 places. Preference for solar energy facilities was the highest at 57.8%. (2) The revised act sets the obligatory supply percentage of new & renewable energy for each public building: it is 9.0% for a tax office, 4.2% for a dong office, 8.2% for a public health center, and 12.6% for a fire station. All the public buildings except for fire stations failed to meet 10% expected energy consumption, a revised standard. (3) Energy consumption of each public building was 120.6TOE for a tax office, 124.3TOE for a dong office, 166.4TOE for a public health center, and 174.6TOE for a fire station. The energy consumption was comprised of 80% electric power, 18% urban gas, and 1% oil. (4) Electric power consumption per person in the room was high at a dong office, and fuel consumption per person in the room was high at a public health center. In addition, electric power consumption per unit space was high at a public health center, and fuel consumption per unit space was high at a fire station. (5) In all the four public buildings, power load had the highest basic unit percentage at average 55%, being followed by heating load (21.2%), cooling load (15%), and water heating load (7%). A tax office and fire station had 2% load due to cooking facilities.

• 한국지열·수열에너지학회논문집
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• 제5권2호
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• pp.7-12
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• 2009

The fossil fuel has been used as the main resource of national development. Through this process, many environmental problems have happened. For example, we depend 97% energy on import for national spending and the exhaustion of the fossil fuel is at an important issue nowadays. So more people are interested in renewable energy which is more environmental and never be gone. However, the supply doesn't go on smoothly because of some problems such as capital condition, the limitation of geographical features and low technology, etc. In conclusion I'd like to check some policies and support systems about renewable energy first, and then to find problems for adapting other area through the comparison in this thesis.

• 한국수소및신에너지학회논문집
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• 제20권1호
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• pp.31-37
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• 2009

An ejector is a machine utilized for mixing fluid, maintaining a vacuum, and transporting fluid. The Ejector enhances system efficiency, are easily operated, have a mechnically simple structure, and do not require a power supply. Because of these advantages, the ejector has been applied to a variety of industrial fields such as refrigerators, power plants and oil plants. In this work, an ejector was used to safely recycle anode tail gas in a 5 kW Molten Carbonate Fuel Cell system at KEPRI(Korea Electric Power Research Institute). In this system, the ejector is placed at mixing point between the anode tail gas and the cathode tail gas or the fresh air. Commercial ejectors are not designed for the actual operating conditions for our fuel cell system. A new ejector was therefore designed for use beyond conventional operating limits. In this study, the entrainment ratio is measured according to the diametrical ratio of nozzle to throat in the designed ejector. This helps to define important criteria of ejectors for MCFC recycling.