• Journal of Korean Society for Atmospheric Environment
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• v.25 no.1
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• pp.1-14
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• 2009

Wind energy has been recognized as one of the most important and fastest growing energy resources without emission of air pollutant. Thus, it is necessary to predict wind speed and direction accurately both in time and space toward the efficient usage of wind energy. Numerical simulation experiments using the Fifth-Generation Mesoscale Model (MM5) are carried out to clarify the impact of surface observation data assimilation on the estimation of wind energy resources. The EXP_Radius run was designed with respect to the radius of influence in the Four-Dimensional Data Assimilation (FDDA), and the EXP_Impact run was made by changing the nudging coefficient that determines the relative magnitude of the nudging term. The simulation period covers a clear-sky event on 3 - 5 June 2007 and another is on 2 - 4 December 2006. It is found that the simulated results are very sensitive to the radius of influence and nudging parameters in the FDDA. The further analysis of the results shows that the impact of the radius of influence tends to be stronger in weak synoptic flow episode than that in strong synoptic flows episode. The nudging factor is also sensitive to the intensity of the synoptic flows.

• Journal of the Korean Solar Energy Society
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• v.25 no.3
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• pp.37-45
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• 2005

Higher requirement of advanced building design code and the development of construction technique have resulted in more thermal and air tight buildings. This has caused the sick building syndrome in a indoor air quality has been relatively getting worse. A new concept with a solar fresh air heating and electrostatic precipitator or called as STCC(Solar Transpired Collector and Cyclone) has been proposed to solve this IAQ issue. This paper describes the assessment study of STCC system under different outdoor airflow rates. The experiment was carried out under real condition with 30CMM STCC system test facility. Incense smoke was used to study the particle concentration decay trends under outdoor airflow rates 0CMM, 10CMM, 20CMM, 30CMM, with applied voltages of 5kV and 15kV for collecting and discharging electrodes of an Electrostatic Precipitator. Result shows that the particle decay increases by increasing the outdoor airflow rates. The collection efficiency, dust cleaning effectiveness(P) and application area calculation result comparisons have also been studied. This factors could be used to estimate how a dust of indoor air quality(IAQ) and removed for a building space with a STCC system.

• 한국태양에너지학회:학술대회논문집
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• 2008.04a
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• pp.160-165
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• 2008

The concern in energy reduction in the field of architecture which takes up a big weight in domestic energy consumption is gradually increasing. For this reason, a lot of research work on this matter is being carried out. Particularly, it is generally required that currently used system in a structure for energy reduction should be maximized in its efficiency. In addition, research on several energy reduction typed systems is underway. Such a research work should not only include the one in time of the present but also keep up with the trend for future-oriented research. This research paper forecasted and analyzed the trend for global warming and demand of a structure for energy in the future by applying climate scenarios to cooling degree-day and heating degree-day. Also, this research found out the decrease in heating degree-days and increase in cooling degree-days until this moment due to the progress of global warming. In addition, as for heating degree-days in the future forecasted on the basis of HadCM3, it is estimated that the range of decrease could be ever bigger starting 2040 in case of Seoul and also starting 2010 in case of Ulsan ever after respectively. In case of cooling degree-days, it is estimated that its increase range could be bigger abruptly starting 2050, and after 2080, its increase range would be much bigger.

• KIEAE Journal
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• v.14 no.6
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• pp.99-104
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• 2014

Recently supply of low energy house is increasing which can enhance energy efficiency and indoor environment comfort. Low energy house have to secure air tightness as well as thermal performance so house become high airtightness and inevitably need heat recovery ventilator to enhance indoor air quality. However, most of current ventilation systems are one-click, controlling the entire space so it causes increasing of heating load and fan power which makes it hard to save energy. Thus, Individual Control system is required which can achieve both enhancing indoor air quality and decreasing heating load and electric fan power. Thereby, in this study, we analyzed the correlation between ventilation and fan power through mock-up experiment and measured ventilation load under individual control system. As a result, under the condition of $24^{\circ}C$ of indoor temperature for 6 month(November to April) in Daejeon, ventilation load by fan speed was $10.9{\sim}19.6kWh/m^2{\cdot}a$ when operated 24 hours and $7.6{\sim}13.7kWh/m^2{\cdot}a$ when operated 12 hours in night time. In addition, it is possible to reduce at most 60% of ventilation load under the individual control system; measured ventilation load was $7.4kWh/m^2{\cdot}a$ when operated 24 hours, and $5.5kWh/m^2{\cdot}$ when operated 12 hours in night time.

• Journal of Hydrogen and New Energy
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• v.25 no.2
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• pp.161-172
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• 2014

Hydrogen, which can be produced from abundant and widely distributed renewable energy resources, seems to be a promising candidate for solving the concerns for improving energy security, urban air pollution, and reducing greenhouse gas emissions. The two primary motivating factors for hydrogen economy are fossil fuel supply limitations and concerns about global warming. But the safety issues associated with hydrogen economy need to be investigated and fully understood before being considered as a future energy source. Limited operating experience with hydrogen energy systems in consumer environments is recognised as a significant barrier to the implementation of hydrogen economy. To prevent unnecessary restrictions on emerging codes, standards and local regulations, safety policies based on real hazards should be developed. This article studies briefly the direct impact-distances from hazard events such as hydrogen release and jet fire, and damage levels from hydrogen gas explosion in a confined space. Based on the direct impact-distances indicated in the accident scenarios and consumer environments in Korea, the safety policies, which are related to hydrogen filling station, hydrogen fuel cell car, portable fuel cell, domestic fuel cells, and hydrogen town, are suggested to implement hydrogen economy. To apply the safety policies and overcome the disadvantages of prescriptive risk management, which is setting guidance in great detail to management well known risk but is not covering unidentified risk, hybrid risk management model is also proposed.

• Journal of the Korean Institute of Gas
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• v.17 no.2
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• pp.78-84
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• 2013

A numerical study on the heat and fluid flow has carried out for the design of the steam reforming reactor which consists of six reforming tubes and one burner. Reforming reaction calculation is coupled with the heat and fluid flow one. The burner type in the reforming reactor is chosen through the fluid flow calculation according to different type of burner structure. It is shown that the significant temperature gradient exists in the reforming reactor, affecting the component variation along the length of reforming tube. The component ratio of reforming gas is changed by the variation of SCR and GHSV.

• Journal of Navigation and Port Research
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• v.33 no.6
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• pp.457-462
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• 2009

In this paper we suggest optimal positioning algorithm for DER(distributed energy resource)s near ocean side by using Newton-Rhapson load flow calculation. By installing DERs within urban area, electric power can be effectively transmitted to each loads without constructing additional large scale power stations and transmission lines. Therefore, DERs have attracted worldwide attention as urban area energy sources. However, there are quite a few studies for estimation of power loss due to DERs' location change within urban area Hence, in this study, an optimal positioning scheme for DERs is proposed in order to minimizing electrical power loss.

• Journal of Energy Engineering
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• v.16 no.3
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• pp.93-102
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• 2007

This paper presents a scenario evaluation model of the AHP (Analytic Hierarchy Process) to evaluate dismantling scenarios considering quantitative and qualitative considerations. And decommissioning information producing modules which can obtain a dismantling schedule, quantify radioactive waste, visualize a radioactive inventory, estimate a decommissioning cost, and estimate a worker's exposure was developed to assess qualitatively decommissioning information. The digital mock-up (DMU) system was developed to verify dismantling processes and find error of scenarios in virtual space. It combines and manages the decommissioning information producing modules, the decommissioning DB, and the dismantling evaluation module synthetically. By using AHP model and DMU system, the thermal column in KRR-1 was evaluated on plasma arc cutting scenario and nibbler cutting scenario using the developed decommissioning DMU system.

• Korean Journal of Organic Agriculture
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• v.17 no.3
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• pp.307-326
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• 2009

The present study suggests a concept of resources circulation type agriculture and a concept of a livestock zone related to it and evaluated economical efficiency about a possibility of the resources circulation type livestock zone based on the concept. As a result, when the resources circulation type livestock zone is operated in an area of 1,300ha, it was evaluated that the profit of 11,244 hundred thousand won per year is generated, compared to the conventional agriculture. When light and heat expenses and roughage of Hanwoo production, production of TMR forage as well as income of the energy and composting business of livestock manure at the recycling center were considered in addition to that, it was judged that the present zone development bushiness has enough business feasibility. However, it is necessary that the support regulations, etc. is constructed so that all produced compost byproducts are used at farmhouses and the system related to facility investment assurance and assistance of operating expenses is maintained. It is thought that the complement of a system is also necessary so that energy or power generation expenses can be operated in the same conditions as other new & renewable energy, and the nation's purchase of carbon credits(CDM) is investigated and systemized in the early period, and construction of a revitalization plan of the business through budget securing of the Ministry of Agriculture and Forestry related to the trade of CDM and carbon emission rights is also a business that should be urgently developed. In the future, the change of an outside environment will further promote use of the energy. Also, as people, who don't know agriculture. farm village, increase day by day because of population concentration in a city, an opportunity that can new added value through experience tourism or educational programs utilizing them is increasing. Accordingly, if programs utilizing social characteristics, such as utilization as a space of tourism. leisure. experience, system construction of bio-energy and system construction that Micro Grid or Smart Grid as a dispersed storage and generation system is stabilized, are constructed, it can be said that revitalization or success conditions of the zone is further achieved.

• Journal of the Korean Solar Energy Society
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• v.35 no.4
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• pp.17-24
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• 2015

The formation of heat islands causes high energy demand for space cooling and peak cooling loads in conditioned buildings. High-temperature fluctuations on a building roof may cause mechanical stress and increase surface deterioration. Thermal energy storage (TES) systems using microencapsulated phase-change materials (MPCMs) have been recognized as one of the most advanced energy technologies for enhancing the energy efficiency and sustainability of buildings. In this study, we prepared MPCM/paint composites for mitigating the heat island effect and reducing peak temperature. In addition, we carried out thermal and physical analysis of prepared MPCM composite samples by means of SEM, FTIR spectroscopy, DSC, and TGA. Further, we evaluated the dynamic heat transfer performance of heat-storage tiles painted with 10 g of heat-storage paint. From the obtained results, we deduced that MPCM/hydrophilic paint composites are more applicable to various fields, including the building sector, than MPCM/hydrophobic paint composites. On the basis of SEM and FTIR spectroscopy results, we concluded that materials with hydrophilic properties are more compatible with MPCMs than those with hydrophobic properties. In addition, DSC analysis results revealed that MPCM/hydrophilic paint composites have better compatibility, higher latent heat capacity, and better thermal properties than other composites. TGA results showed that hydrophilic-paint-based composites have higher thermal durability than hydrophobic-paint-based composites. Finally, a lot of MPCM-loaded heat-storage tiles showed lower peak temperatures at all measurement positions.