• Journal of Power System Engineering
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• v.21 no.3
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• pp.5-11
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• 2017

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.245-245
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• 2007

• Proceedings of the Korean System Dynamics Society
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• 2005.04a
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• pp.149-162
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• 2005

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.2
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• pp.230-236
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• 2009

In this paper, in order to utilize new and renewable energy a grid-connected parasol-type solar power generation system is presented. The proposed power system combining with commercial electric power system is designed to meet the need fur maximum power consumption and parasols for the people staying at beach during hot summer. Solar electric power can be charged in rechargeable batteries during day time and used to provide charged electric power to loads like lamps and fans during night time, A battery charge-discharge controller is required for the good performance of batteries to be charged. The presented battery controller is designed based on high performance microprocessor for precise charge-discharge operations. An alarm circuit to give notice of battery exchange time and other convenient functions are installed in the system. We implemented the proposed solar power generation system at East Sea beach during peak summer season to verify its productivity and performance by experiments.

• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.470-478
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• 2016

Greenhouse gas (GHG) emissions caused by fossil fuels consumption is one of the challenging issues worldwide. Renewable energy source (RES)-based energy supply system can be a promising alternative to the current fossil fuel-based system. In this study, we propose an optimization approach for designing a stand-alone hybrid energy supply system using RES and evaluating economic performances of the energy systems. The suggested approach is used to answer the questions; i) what technology is suitable to various demand sectors in different regions, and ii) how does it cost to meet the demand in term of the levelized costs of energy (LCOE). We illustrate the applicability of the proposed approach by applying to the design problem of energy supply systems for residential, agricultural and commercial sectors of Korea. As the results of LCOE analysis, for the residential sector has the LCOE ranging of $0.37~$0.44/kWh, the agricultural sector of $0.15~$0.61/kWh and the commercial sector of $0.12~$0.28/kWh.

• Journal of the Korean Solar Energy Society
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• v.27 no.1
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• pp.47-54
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• 2007

Interests on renewable energy are increased due to oil price and environmental problems aroused from the fossil energy usage. In this study, performances of a solar assisted hybrid heat pump system are analyzed by experimental method. The developed system could runs at two types of operating mode. When the storage temperature is higher than the set temperature, the stored hot water in storage tank is supplied to the load directly. On the other hand, when the storage temperature lower than the set temperature, the water inside of the storage tank is used as heat source of the heat pump. In this study, the system control temperature for the alternation of the operating mode is set to $40^{\circ}C$ of the storage tank outlet. As results, it is founded that the COP of the developed heat pump system shows between 3.0 and 3.5. It is resonable performance for the heating system with a renewable energy as secondary heat source. The solar collect used in this study could supplies heat to the storage tank at over 400 W/m2 solar intensity. If the irradiation is lower than the 400 W/m2, the circulation pump stored and it could not supply heat to the storage tank. It is found that the difference temperature between the outlet of the storage tank and collector is $3^{\circ}C$. Even though, the extended study should be conducted to get a optimum performance of the developed system with various operating condition and control strategies.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.9
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• pp.958-963
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• 2012

Characteristics of off-grid hybrid renewable energy sources for high mountain villages are discussed. Considering reliability of electric power generation, Photovoltaic (PV)-wind hybrid and PV-hydro hybrid system are suggested. Connecting two or more villages with these hybrid systems, an extended hybrid off-grid can be formed. Sustainability of entire system is important in design of off-grid system, and income generation of the village people using the electricity should be considered.

• Journal of IKEEE
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• v.22 no.3
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• pp.729-732
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• 2018

This paper performs Agregation for supplementing the additional generator when reflecting the plan DB based on a number of renewable power sources, line and transformer data. In this study, modeling of a line and a generator through a Collector method and a Step-Up-Transformer among Aggregation execution methods is conducted.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.1
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• pp.16-21
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• 2012

The growth in IT industry has brought a corresponding rise in the number of connected digital devices in the distribution network. These digital loads lead to AC to DC conversion losses in order to supply power to them. The more the renewable energies and plug-in electrical vehicles penetrated our lives, the more the electrical losses are caused by AC to DC conversion process. Hence, this paper suggests the methodology for evaluating the amount of power supplied according to the ratio of DC power supply and performs an economic analysis of DC distribution system considering grid parity. In here, the cost of carbon emission reduced by renewable energy is also concerned.

• Journal of the Korean Institute of Rural Architecture
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• v.20 no.1
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• pp.69-76
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• 2018

This study is to research technical measures for improving energy efficiency in the conservation and reuse of historic buildings focused on the recent research trends and case studies of the west. These measures are broadly classified into three types, the passive measures for saving energy and increasing comfort, the most cost-effective energy saving strategies, and the renewable energy sources. Firstly, the passive measures are divided into the elements and systems. The passive elements are awnings and overhanging eaves, porches, shutters, storm windows and doors, and shade trees. There are also the natural ventilation systems such as the historic transoms, roofs and attics to improve airflow and cross ventilation to either distribute, or exhaust heat. Secondly, the most cost-effective energy efficiency strategies are the interior insulation, airtightness and moisture protection, and the thermal quality improvement of windows. The energy efficiency solutions of modern buildings are the capillary-active interior insulation, the airtightness and moisture protection of interior walls and openings, and the integration of the original historic window into the triple glazing. Beyond the three actions, the additional strategies are the heat recovery ventilation, and the illumination system. Thirdly, there are photovoltaic(PV) and solar thermal energy, wind energy, hydropower, biomass, and geothermal energy in the renewable energy sources. These energy systems work effectively but it is vital to consider its visual effect on the external appearance of the building.