• Advances in Energy Research
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• v.4 no.1
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• pp.47-68
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• 2016

A well designed hybrid power system (HPS) can deliver electrical energy in a cost effective way. In this paper, model for HPS consisting of photo voltaic (PV) module and wind mill as renewable energy sources (RES) and solar lead acid battery as storage device connected to unidirectional grid is developed for peak demand reduction. Life time energy cost of the system is evaluated. One year hourly site condition and load pattern are taken into account for analysing the HPS. The optimal HPS is determined for least life time energy cost subject to the constraints like state of charge of the battery bank, dump load, renewable energy (RE) generation etc. Optimal solutions are also found out individually for PV module and wind mill. These three systems are compared to find out the most feasible combination. The results show that the HPS can deliver energy in an acceptable cost with reduced peak consumption from the grid. The proposed optimization algorithm is suitable for determining optimal HPS for desired location and load with least energy cost.

• Journal of the Korean Solar Energy Society
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• v.30 no.2
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• pp.22-32
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• 2010

The world is facing environmental problem described as climate change and exhaustion of fossil fuel. In order to solve theses problems, importance of renewable energy is extremely growing. For stable energy supply, it is need to apply hybrid renewable energy systems in urban-scale, because some renewable energy system' outputs are greatly influenced by climatic condition. Especially, solar irradiation and wind velocity are influenced by urban geometric environment as well as climatic condition. Therefore it is necessary to evaluate the renewable energy potential according as urban form. This study aims to evaluate the potential of solar energy and wind energy in urban-scale and classify urban type according as characteristics of urban forms. The results of this study will be used to develop renewable energy system application guidelines for urban and energy planning.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.529-533
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• 2012

By introducing RPS(Renewable Portfolio Standard) for reduction of greenhouse gas, Renewable energy sources have becoming widespread gradually. However, Renewable energy sources, such as wind power and PV are difficult to control the output and they have intermittent characteristics of the output. These characteristics would cause some problems when it is connected in the power system. In order to solve these problems, Energy Storage Systems(ESS) are considered to use. Although there are many different storage devices, the utilization of Secondary Battery is the one of the best ways to stabilize an output fluctuation of RES because of its fast responsibility. For that reason, it would better fit a large-capacity of Secondary battery for stabilization. However, batteries cannot be installed with a large capacity blindly because of its expensive cost. So to select proper capacity of the battery is an important consideration. This paper presented a methodology for the optimal capacity and operation of ESS in microgrids.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.7
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• pp.417-427
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• 2014

Renewable energy sources such as solar, wind and hydro provides utilizing renewable power and reduce the using fossil fuels. On the other hand, it is too critical to apply power system due to the intermittent nature of renewable energy sources, the continuous fluctuations of the power load, and the storage with high energy density. Energy storage system, including pumped-hydroelectric energy storage, compressed-air energy storage, superconducting magnetic energy storage, and electrochemical devices like batteries, supercapacitors and others have shown that solve some of the challenges. In this paper, we review the current state of applications of energy storage systems, and atomic layer deposition technology, graphene materials on the energy storage systems and processes.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.18-26
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• 2014

A microgrid can play a significant role for enlargement of renewable energy sources and emission reduction because it is a network of small, distributed electrical power generators operated as a collective unit. In this paper, an application of optimization method to economical operation of a microgrid is studied. The microgrid to be studied here is composed of distributed generation system(DGS), battery systems and loads. The distributed generation systems include combined heat and power(CHP) and small generators such as diesel generators and the renewable energy generators such as photovoltaic(PV) systems, wind power systems. Both of thermal loads and electrical loads are included here as loads. Also the emissions trading scheme to be applied in near future, the cost of unit start-up and the operational characteristics of battery systems are considered as well as the probabilistic characteristics of the renewable energy generation and load. A mathematical equation for optimal operation of this system is modeled based on the mixed integer programming. It is shown that this optimization methodology can be effectively used for economical operation of a microgrid by the case studies.

• New & Renewable Energy
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• v.2 no.1 s.5
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• pp.21-25
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• 2006

Standards are increasing of importance for New & Renewable energy. The rapid growth of production is one reason for this but standards are equally important in ensuring the quality and reliability of installed New & Renewable energy systems, which have a propound impact on acceptance of the technology in the expanding marketplace. Korea government (Korea Agency for Technology and Standards, KAIST)make and implement a five year plans for promotion of international standardization of this field from 2004. KATS leads the technology innovations and eventually increases the international competitiveness. Strategic collaboration with other countries is also strengthened through Korea's participation in international standards and conformity assessment system such as IECEE(IEC system for conformity and certification of electrical equipment). One of the major goals of the Plan is to facilitate trade between Korea and its trading partners by emphasizing harmonization of its national conformity assessment system with international norms.

• Journal of the Korean Solar Energy Society
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• v.36 no.6
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• pp.13-24
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• 2016

The government introduced a mandatory installation system of new & renewable energy for public building to meet the target of greenhouse gas reduction and also suggest a correction factor for new renewable energy to expand the installation of various new & renewable energy systems. The introduction of correction factors, however, was followed by the reduction of installation size of new & renewable energy sources. Assuming that it was caused by a correction factor for each new renewable energy source calculated by the initial costs, this study proposed a new correction factor approach based on payback periods to reflect the technology element in the calculation process of correction factors additionally. The application results of new correction factors show that it was possible to do complex calculations including the economic and technological aspects to select a new & renewable energy system and that the installation size was also enlarged.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.5
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• pp.2177-2193
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• 2018

This paper studies resource allocation schemes for the relay-aided cooperative system consisting of multiple source-destination pairs and decode-forward (DF) relays. Specially, relaying selection, multisubcarrier pairing and assignment, and power allocation are investigated jointly. We consider a combinatorial optimization problem on quality of experience (QoE) and energy consumption based on relay-aided cooperative system. For providing better QoE and lower energy consumption we formulate a multi-objective optimization problem to maximize the total mean opinion score (MOS) value and minimize the total power consumption. To this end, we employ the nondominated sorting genetic algorithm version II (NSGA-II) and obtain sets of Pareto optimal solutions. Specially, two formulas are devised for the optimal solutions of the multi-objective optimization problems with and without a service priority constraint. Moreover, simulation results show that the proposed schemes are superior to the existing ones.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.04a
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• pp.175-180
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• 2009

According to an increasing demand of political support and development on renewable energy as a solution for the energy problem in Korea, the government has established a goal to raise renewable energy supply from 2.27% to 5% until 2011. Especially in the case of public building in which energy use is in great demand, it would bring a great advantage to develop and utilize the Photovoltaic System as an electric energy and Geothermal Heat Pump System as a thermal energy. On the occasion of Photovoltaic System, Photovoltaic module can be used as an architectural material so that it can reduce construction cost and when we use solar energy, it is possible to make building's own power supply. As for Geothermal Heat Pump System, It can be used infinitely as long as the solar energy exist and operation cost is cheap and yearly efficiency is stable. However, we need to make a plan to reduce early investment expanses for these two renewable energy systems and to expand a diffusion rate as we develop a competitive domestic technology level. So in this study, we are going to perform evaluation of economical efficiency according to the introduction of Photovoltaic System and Geothermal Heat Pump System in public buildings which will be built up inside of Daegu Sin-seo innovation city. As a first step, we will investigate present installation condition of these two renewable energy systems and based upon that, will seek efficient introduction program of renewal energy systems that can be applied in public buildings.

• Journal of the Korean Institute of Rural Architecture
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• v.24 no.4
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• pp.107-115
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• 2022

This study investigated the status of resident participation in the policy of supplying new and renewable energy in rural areas. According to the survey, most of the rural residents were well aware of the new and renewable energy supply project promoted by the government. However, it was found that participation in the project was difficult mainly for economic and social reasons. In order to activate the participation of rural residents who can't participate in the renewable energy power generation project for economic and social reasons, it is necessary to develop and promote business models and support policies for power generation projects in which village communities participate. Changes in residents' acceptability due to resident education and operation for solar power systems were analyzed. As a result of the survey, it was found that the satisfaction of rural residents was high when new and renewable energy power generation projects were introduced in rural areas. Therefore, it is thought that the government's goal of increasing farm household income and expanding the supply of new and renewable energy in rural area can be successfully achieved by the improvement of resident acceptability and the increase of the participation rate. Lastly, this study presented a plan to improve the resident acceptability of the renewable energy system by using the rural solar project and survey results.