• Journal of Energy Engineering
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• v.21 no.4
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• pp.435-443
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• 2012

The combination of space shortage and the high population density concentrated in urban areas of South Korea has resulted in the growth of large-scale high-rise residential complexes, naturally affecting water and hot water usage patterns as well. But the current designs for water and hot water supply in South Korea rely mostly on international design standards and data calculated on site due to the severe shortage of basic data in relation to actual use, which result in the frequent problem of the under-or over-design of water and hot water supply. The following study measures the hot water supplier's conditions and the user's heat usage to realize the amount of time required for hot water supply load generation and the pattern of actual use in order to create basic data for effective hot water supply facility design and maintenance.

• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.381-389
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• 2015

In this study, the effects of moisture content and particles size of ground particles of torrefied larch chips on the pelletizing process were investigated depending on torrefaction conditions ($220^{\circ}C$-50 min, $250^{\circ}C$-50 min, $250^{\circ}C$-120 min). The moisture content in the torrefied chip decreased to 0.69~1.75%, while ash content and calorific value increased compared to untreated chip. In addition, weight loss significantly increased during torrefaction due to hemicellulose degradation. The carbon content in torrefied larch chip increased compare to untreated larch chip, while the hydrogen and oxygen contents decreased. The lignin and glucan contents in torrefied larch chip increased with increasing severity of the torrefaction condition, while hemicellulose decreased. In the particle size distribution of ground particles of torrefied larch chip, larch torrefied at severe conditions was found to produce smaller particles (~1 mm) than that of the larch torrefied at mild conditions. Macropore (over $500{\AA}$) in the torrefied particle was produced during torrefaction. During the pelletizing using ground particles of torrefied larch chip, the pressure needed in pelletizing decreased and pellet length increased with increasing moisture content, regardless of the particle size.

• Journal of Digital Convergence
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• v.15 no.10
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• pp.221-232
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• 2017

In recent years, the development and market participation of major makers of next-generation eco-friendly vehicles has been accelerating. Consumer interest has also increased. Consumer characteristics, consumption type, characteristics of next-generation eco-friendly vehicles, and government policies on next-the results of this study are as follows. As a result of this study, it was found that the characteristics of consumers (by sex, age, monthly average income), types of consumers (price value pursuit type, individual value pursuit type), There was no significant difference between the consumers, and the purchasing intention was not significantly different by gender, age, and monthly income, but there was a significant difference in purchase intention according to the type of consumer. The positive effects of consumer purchase behavior on brand image, color, design, etc, have positive (+) effect on eco - friendly vehicles. And social environment value seeking type among consumer types are significant in relation to purchase intention. To have three support the government's carbon dioxide (per ton of 5,000 won, per ton of 10,000 won), national or local government vehicle price support directly gasolin tax, disel tax, carbon taxes, such as fuel-related tax relief, etc. was found to have positive effect.

• Korean Journal of Environmental Agriculture
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• v.26 no.1
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• pp.1-6
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• 2007

In view of energy supply, biogas can be seen as alternative fuel by substituting considerable amount of fossil fuel and may be utilized for heat and power production or for transport fuel production ($CH_4-enriched$ biogas). The aim of this research is to analyse the emission of $NO_x$ and CO from biogas fired combustion engine for electric power production. The result indicate a significant effect of biogas composition ($CH_4-CO_2$ ratio) and biogas flow rate on the air pollutants emission. The emission factors from this study were compared with those of U.S. EPA. Low $CH_4-CO_2$ ratio condition typically shows the lower $NO_x$ and CO emission than higher $CH_4-CO_2$ ratio condition. At normal $CH_4-CO_2$ ratio (7:3) emission factors of $NO_x$ and CO were 1.29 and 30.43 g/MMBtu, respectively. At low $CH_4-CO_2$, ratio (6:4) emission factors of $NO_x$ and CO were 0.646 and 60.86 g/MMBtu, respectively, It should be emphasized that the actual emission may vary considerably from these results due to operating conditions including torque load and engine speed.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.2
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• pp.357-368
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• 2018

For well over 100 years, oil has enabled remote communities to generate electricity and enjoy the benefits of a consistent electrical supply. Relying solely on oil for electricity generation has left island and remote communities exposed to several risks and drawbacks. Oil-based electricity generation is often more expensive and subject to price volatility, which can result in the use of risky fuel hedging strategies. The residents of islands and remote communities express concern over the future impacts of climate change or insist on their opinions for the corresponding action with reduction of carbon emissions. These risks and drawbacks can be overcomed with continuing cost reductions in solar, wind, and energy storage technologies by maker. Reducing costs is not always a straightforward process, relying on more diversely and renewably arranged renewable energy sources led to reduced local construction cost in every situation reviewed in this study. In this paper, a convenient and simple design solution which will facilitate the optimum location and transmission route of renewable energy facility using GIS(Geographic Information System) is proposed. The suggested solutions exercised to the case of geomoon island using GIS and identified by local site survey.

• KSBB Journal
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• v.20 no.6
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• pp.393-400
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• 2005

Hydrogen($H_2$) as a clean, and renewable energy carrier will be served an important role in the future energy economy. Several biological $H_2$ production processes are known and currently under development, ranging from direct bio-photolysis of water by green algae, indirect bio-photolysis by cyanobacteria including the separated two stage photolysis using the combination of green algae and photosynthetic microorganisms or green algae alone, dark anaerobic fermentation by fermentative bacteria, photo-fermentation by purple bacteria, and water gas shift reaction by photosynthetic or fermentative bacteria. In this paper, biological $H_2$ production processes, that are being explored in fundamental and applied research, are reviewed.

• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.739-744
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• 2013

In this study, torrefaction was performed to improve fuel properties of Larch. The optimal condition for torrefaction was investigated by response surface methodology. The torrefaction temperature and time ranged $220{\sim}280^{\circ}C$ and 20~80 min, respectively. As the torrefaction temperature and time increased, the carbon content of torrefied biomass increased from 49.36 to 56.65%, while its hydrogen and oxygen contents decreased from 5.56 to 5.48% and from 37.62 to 31.67%, respectively. The weight loss and calorific value increased with SF, while energy yield decreased. At the severe torrefaction condition (SF 7), the weight loss and calorific value were 26.58% and 22.30 MJ/kg, respectively. The energy contained in torrefied biomass increased to 20.41%, when compared with the untreated biomass. As the torrefaction severity increased, the energy yield decreased due to the relatively high weight loss of biomass. Therefore, the highest energy yield was obtained at high calorific value and low weight loss of biomass (SF 5.72).

• Environmental and Resource Economics Review
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• v.16 no.2
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• pp.275-311
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• 2007

Hydrogen energy is emphasized as a substitutable energy of carbon-based energy system in the future, since it is non-depletable and clean energy. Long term vision of Korean government on the national energy system is to promote hydrogen energy by 15% of final energy demand until 2040. This study analyzes economic impacts of hydrogen energy development employing a dynamic CGE model for Korea. Frontier technology such as hydrogen energy is featured as slow diffusion at the initial stage due to the learning effect and energy complementarity. Without government intervention, hydrogen energy would be produced upto 6.5% of final energy demand until 2040. However, if government subsidizes sales price of hydrogen energy by 10%, 20%, and 30%, share of hydrogen energy would increase 9.2%, 15.2%, and 37.7% of final energy demand. This result shows that the slow diffusion problem of hydrogen energy as frontier technology could be figured out by market incentive policy. On the other hand, production levels of transportation sector would increase while growth rate of oil and electricity sectors would decline. Household consumption would be affected negatively since increase of consumption due to the price decrease would be overwhelmed by income reduction owing to the increase of tax. Overall, GDP would not decrease or increase significantly since total production, investment, and export would increase even if household consumption declines.

• Clean Technology
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• v.18 no.3
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• pp.229-249
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• 2012

At present, global warming and depletion of fossil fuels have been one of the big issues which should be solved for sustainable development in the future. CCS (carbon capture and sequestration) technology as the post $CO_2$ reduction technology has been considered as a promising solution for global warming due to increased carbon emission. However, the environmental and ecological effects of CCS have drawn concerns. There are needs for noble post reduction technology. More recently, CCU (carbon capture and utilization) Technology, which emphasizes transforming carbon dioxide into value-added chemicals rather than storing it, has been attracted attentions in terms of preventing global warming and recycling the renewable carbon source. In this paper, various technologies developed for carbon dioxide conversion both in gas and liquid phase have been reviewed. For the thermochemical catalysis in gas phase, the development of the catalytic system which can be performed at mild condition and the separation and purification technology with low energy supply is required. For the photochemical conversion in liquid phase, efficient photosensitizers and photocatalysts should be developed, and the photoelectrochemical systems which can utilize solar and electric energy simultaneously are also in development for more efficient carbon dioxide conversion. The energy needed in CCU must be renewable or unutilized one. CCU will be a key connection technology between renewable energy and bio industry development.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.4
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• pp.717-727
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• 2017

Researches on the emissions of greenhouse gases in the construction industry, which accounts for 40% of raw materials, 30% of energy consumption, and 30% of $CO_2$ emissions in the entire industry, are mainly focused on studies of LCA. However, it is assessed that $CO_2$ emissions are higher in construction sequence than in operation sequence. Also, it is considered that construction machinery using fossil fuel is a main factor causing environmental load in construction sequence. Therefore, this study analyzes the workload and engine RPM characteristics of the excavator which is the second largest number of registered construction machinery in Korea and the highest utilization rate in actual construction site. The excavator is divided into non-load states and load states where power is transmitted to the excavator. The exhaust gas is analyzed by a direct measurement method using PEMS equipment. $CO_2$ emissions are estimated by analyzing the relationship between RPM and exhaust emission characteristics according to the actual driving conditions. Additionally, we analyze the difference between $CO_2$ emissions of construction machine calculated by this study and $CO_2$ emissions calculated by using carbon emission coefficient.