• Proceedings of the IEEK Conference
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• 2000.06e
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• pp.147-150
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• 2000

Manual and predictive defrosting method is used in current refrigerators, which have several problems in terms of energy consumption and efficiency. fuming the defrosting system on by the amount of frost remains to be an important problem which has to be improved by refrigerator manufacturers. The sensing of the amount of frost by FDS(Frost Detecting Sensor) and its proper mounting point are investigated in the paper. Also the realization of actual defrosting system through experiments of operation, energy consumption and sensing mechanism is presented.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.917-919
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• 1997

Recently, electric industry confront a strategical change and high competiveness environment in the course of deregulation. Especially, rapid growth in electricity demand, financial need for new power plant construction, and environmental problems have led to search for more efficient energy production and energy conservation technologies in Korea. Due to the potential energy and cost savings, DSM(Demand-Side Management) plays and important role in the electric resource planning. In this paper, we suggest DSM potential evaluation procedures and algorithm. Also, we present screening analysis methods for DSM potential evaluation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.11
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• pp.25-31
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• 2009

In this paper we propose an improved energy aware greedy perimeter stateless routing protocol (EAGPSR) for wireless ad hoc network. The existing greedy perimeter stateless routine (GPSR) has some problems with overloaded node and void situation. The improved EAGPSR protocol is proposed to remedy these problems. It also gives the solution for the fundamental problem in geographical routine called void communication. It considers two parameters (Residual Energy of battery and distance to the destination) for the next hop selection. In order to use efficiently limited-energy of node in wireless ad hoc network, network lifetime is focused. To evaluate the performance of our protocol we simulated EAGPSR in ns-2. The simulation results show that the proposed protocol achieves longer network lifetime compared with greedy perimeter stateless routing (GPSR) and the existing Energy aware greedy perimeter stateless routing protocol (EAGPSR).

• The Journal of Information Systems
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• v.27 no.2
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• pp.95-114
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• 2018

Purpose The recent concern over environmental problems such as greenhouse gas emission and fine dust contributes increasing interest in renewable energies. However the intrinsic characteristics of renewable energies, intermittent and stochastic generation, might cause serious problems to the stability and controllability of power grid. Therefore countermeasures such as virtual power plant (VPP) must be prepared in advance of the spread of uncontrollable distributed renewable energy resources to be one of major energy sources. Design/methodology/approach This study deals with the design concept of the VPP platform. we proposed as a technology solution for achieving the stability of power grid by guaranteeing a single power profile combining multiple distributed power sources with ICT. The core characteristics of VPP should be able to participate in the grid operation by responding to operation instructions from the system operator, KPX, as well as the wholesale electricity market. Findings Therefore this study includes energy storage device(ESS) as a controllable component as well as renewable energy resources such as photovoltaic and wind power generation. Based on this configuration, we discussed core element technologies of VPP and protype design of VPP solution platform according to system requirements. In the proposed solution platform, UX design for the integrated control center and brokerage system were included as well as ancillary service function to respond to KPX's operation instruction with utilizing the capability of ESS. In addition, a simulator was suggested to verify the VPP operations.

• Journal of Biosystems Engineering
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• v.16 no.1
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• pp.83-89
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• 1991

One of the most serious problems in Korean sericulture farms is to improve the adiabatic conditions for the simple silkworm rearing houses which has been widely adapted since early 1980'. Thus, this study is aimed to solve the problems by selecting the thermal screen material and by finding the method of its instalation. For the study, 4 kinds of materials which are (1) TE005,(2) NW60, (3) NW300 and (4) AL110 are selected and 4 different types of methods which are surrounding boundary of rearing bed(type A), surrounding inside of wall and ceiling (type B), installing on inside of wal ony (type C) and installing on ceiling Inly (type D) are installed. Decision criteria of the best combination of screen material and installation methods is made by calculating the heating load coefficients and by testing the application at the simple silkworm rearing houses. The obtained results are summarized as follows ; 1. The effect of thermal screen on reducing the thermal energy is remarkable. It saves energy more 50% than unscreened simple silkworm rearing houses. 2. From a stand point of a good screed material on thermal energy reduction, the NW300, AL110 and PE005 are recommanded materials. However, NW60 and PE005 are regarded as desirable materials from the practical point view. 3. Also, the effect on thermal energy reduction is largely affected by the method of thermal screen installation. The surrounding boundary of the silkworm rearing bed(type A) is the most desirable method to reduce the energy, which saves 56.6% of it. 4. In the practical application, NW60 and type A is considered to be the best combination of material and installation method. By this combination, the level of maximum heating load can be reduced at the rate of 43% for spring season and 40% for autumn season. 5. Another heating method, comparted heating, can be recommended to save the energy.

• Journal of Hydrogen and New Energy
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• v.34 no.2
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• pp.155-161
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• 2023

Recently, a study on alternative and renewable energy is being conducted due to energy depletion and environmental problems. In particular, a hydrogen has the advantage of converting and storing the remaining energy into water-electrolyzed hydrogen through renewable energy generation. In general, due to reasons such as insulation problems, a study on high-pressure hydrogen storage tanks and related parts has recently been conducted. However, in the case of liquid hydrogen, the volume can be reduced by about 800 times or more compared to high-pressure hydrogen gas, so the study on this is needed as a technology that can increase energy density. In this study, the evaporation characteristics were analyzed under fixed heat flux conditions for liquid hydrogen storage tanks and the change in thermal stratification according to sloshing was analyzed. The heat flux condition was fixed at 250 W/m² and the horizontal resonance frequency of the primary mode was applied to the storage tank. As a result, it was confirmed that the thermal stratification phenomenon decreased compared to the case where the slashing was not present due to forced convection when the slashing was present.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.1
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• pp.29-37
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• 2017

Hospitals contribute to energy consumption and have a negative environmental impact. This study aims to find how meaningful energy performance, reflecting good energy management and design, can be planned for hospital buildings, a category encompassing complex buildings with different setups and large differences between them. Energy-consumption characteristics were surveyed throughout Korea to establish statistical energy models. Findings confirm that different hospital departments have hugely different energy-demand profiles. Energy efficiency and energy-saving potentials on HVAC systems are presented. The energy performance analysis can be applied to a wide range of problems in energy-system design and planning, including simulations and optimizations of community energy systems.

• Journal of Information Technology Services
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• v.21 no.6
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• pp.117-125
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• 2022

In respond to climate change caused by global environmental problems, countries around the world are actively promoting the advancement of new electricity industries. The new energy business is being applied to energy storage systems (ESS), electric vehicle charging business, and power demand response using cutting edge technologies. In 2022, the Korean government is also establishing a policy stance to foster new energy industries and making efforts to improve its responsiveness to power demand response with the innovative technologies. In Korea, attempts to commercialize energy power are also being made in the private and public sectors to control energy power in houses, buildings, and industries. For example, private companies, local governments, and central government are making all-out efforts to develop new energy industry models through joint investment. There are forms such as establishing energy-independent facilities by region, establishing an electric vehicle charging system, controlling urban lighting systems with Information technologies, and managing demand between power suppliers and power consumers. This study examined the business model applied with energy storage system, electric vehicle charging business, smart lighting, and power demand response based on information communication technology to examine the site where smart energy system was introduced. According to this study, company missions and government tasks are suggested to apply new energy business technologies as economical energy solutions that meet the purpose of use by region, industry, and company.

• Journal of the Korean Solar Energy Society
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• v.27 no.3
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• pp.127-133
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• 2007

Underfloor air distribution system is generally known to be more energy-saving and provide more comfort as compared with overhead air distribution system. In practice, however, some buildings to which underfloor air distribution system is applied have less effectiveness in saving energy and are getting dissatisfaction with cold draft caused by wind velocity of air distribution in terms of comfort. It is judged that such problems are due to failure to consider properties of underfloor air distribution system in applying it and identical design with the design standards for the existing overhead air distribution system. This study aims at introducing an air conditioning type of the occupied zone for underfloor all distribution system to see its effectiveness in saving energy for air conditioning of the occupied zone through a comparative simulation with the existing air conditioning type.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.713-716
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• 2007

Interests have been focused to the renewable energy because energy cost of fossil fuel increased and global climate change caused by CO2 evolution became severe. To overcome these problems, it is essential to develop the energy conversion technologies of renewable resources. Therefore, production and utilization state of wood and woody waste was firstly investigated and then various technologies (pyrolysis, gasification, and combustion) converting the wood and woody waste to energy were summarized. Some case studies of woody waste utilization in europe was introduced with the policy of EU countries. Economical aspect of woody waste was compared with the current fossil fuels and the energy policy of wood and woody waste was suggested.