• KIEAE Journal
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• v.4 no.4
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• pp.19-26
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• 2004

The purpose of this study was to evaluate the thermal environment of present state and energy consumption and to verify the improvement of energy performance applying free cooling in 5ESS-2000 telecommunication equipment room. Analysis program is used the DOE-2.1E and commercial CFD code, Star-CD. The results of the simulation show that free cooling could reduce 42.1% of cooling energy, increase 48.5% of heating energy because introduced outdoor air must heating and humidification. Therefore free cooling could reduce yearly 34,609.9 kWh of heating and cooling energy and this is reaching to 21.6% of total energy.

• Journal of Internet of Things and Convergence
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• v.7 no.3
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• pp.9-14
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• 2021

This paper discovers the energy loss factors through the insulation diagnosis of houses or buildings, and proposes directions for energy efficiency improvement. The energy efficiency factor of a building consists of insulation diagnosis, thermal bridge diagnosis, window diagnosis, airtight diagnosis, and equipment diagnosis. Among the residents and facilities in the energy welfare blind spot, an energy efficiency diagnosis was conducted for one senior citizen building located in Naju-si, Jeollanam-do, and energy efficiency diagnosis was conducted after insulation was installed. Energy measurement, diagnosis and analysis were performed using the IoT-based integrated wired/wireless energy diagnosis platform, Energy Finder. As a result of comparison, an overall energy saving rate of 16.38% was achieved. Annual heating energy consumption per unit area decreased from 333.51kWh before construction to 277.35kWh after construction, and annual cooling energy consumption per unit area decreased from 5.51kWh before construction to 5.22kWh after construction. The annual primary energy consumption per unit area decreased from 464.52kWh before construction to 403.69kWh after construction, and the annual energy cost was reduced from 3,063,307.14 won before construction to 2,641,072.49 won after construction. The additional improvement work is needed on the standards affecting energy efficiency other than insulation.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.10a
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• pp.327-328
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• 2017

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.8
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• pp.1159-1163
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• 2014

This paper have been dealt with the analysis for energy efficiency improvement effect of unity storage capacity as a part of the energy storage application study to improve energy efficiency in the electric railway systems. Especially, in order to estimate the amount of energy saving according to the variation of power capacity of each storage, the current limit module was mounted on an existing DC electric railway loadflow program which is based on the analysis model for railway system and storages, and combined optimization algorithm to determine optimal voltage boundary.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.678-681
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• 2007

Now Korea depends upon the imported resources for about 97% of total using energy. So from October, 2001 Korean government has supported renewable energy business owners by providing them with Electric Power Industry Basis Fund. Only plant-use electricity of the small hydro power plant is exactly managed, but other renewable energy plants is unprepared or not yet managed. Therefore, in this paper, we'll analyze the plant-use electricity management of the small hydro power and propose improvement plans for plant-use electricity of the photovoltaic power plant.

• Environmental Engineering Research
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• v.21 no.3
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• pp.219-225
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• 2016

Energy self-reliance is important for economic growth and development for any nation. An energy self-reliance technological analysis for Kampala the capital city of Uganda is presented. Three renewable energy sources: Municipal Solid Waste (MSW), solar and wind are assessed for the period of 2014 to 2030. Annual MSW generation will increase from $6.2{\times}10^5$ tons in 2014 to $8.5{\times}10^5$ and $1.14{\times}10^6$ tons by 2030 at 2% and 3.9% population growth respectively. MSW energy recovery yield varies from 136.7 GWh (2014, 65% collection) to 387.9 GWh (2030, 100% collection). MSW can at best contribute 2.1% and 1.6% to total Kampala energy demands for 2014 and 2030 respectively. Wind contribution is 5.6% and 2.3% in those respective years. To meet Kampala energy demands through solar, 26.6% of Kampala area and 2.4 times her size is required for panel installation in 2014 and 2030 respectively. This study concludes that improving renewable energy production may not necessarily translate into energy self-reliant Kampala City based on current and predicted conditions on a business as usual energy utilization situation. More studies should be done to integrate improvement in renewable energy production with improvement in efficiency in energy utilization.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.9 no.1
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• pp.1-7
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• 2013

With the architectural energy saving technique such as building insulation, airtightness etc., changing the indoor temperature and shortening the air conditioning time etc. are the good methods to practice energy saving in our lives. This study aims to seek a way to realize energy saving under investigation through a questionnaire survey about energy consumption condition and energy saving perception. 93% of the respondents recognized the need for energy saving, and 67% said more energy saving would possible in homes. Viable energy saving way was questioned by five steps method. More than 50% responded 'possible' or 'seems possible' at most of the items. Whereas less than 50% responded 'possible' or 'seems possible' at the items of 'lessening the cooling time' and 'lessening the shower time'. Ages of 50s who responded 'possible' or 'seems possible' was relatively less compared to 30s and 40s.

• Journal of Korean Society on Water Environment
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• v.38 no.5
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• pp.231-239
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• 2022

In this study, we applied ENERWATER to evaluate the energy consumption labeling of wastewater treatment plants in Korea using the Korea sewerage statistics data. The results showed that the energy label status was excellent in the SBR process for small and medium-scale wastewater treatment plants and the A2O process for large-scale wastewater treatment plants. The energy labeling of wastewater treatment plants of 50,000 tons capacity was excellent. The statuses of metropolitan cities and Jeollanam-do province were excellent. We analyzed the effects of renewable energy on wastewater treatment plants' energy consumption and found out that digestion gas for large-scale plants and photovoltaic energy for small-scale plants were effective in improving energy labeling. In addition, we compared the energy labels of four wastewater treatment plants in "Z" city and wastewater treatment plant "X" had the best energy label, and the wastewater treatment plants "V" and "Y" had to be selected as priorities for the energy diagnosis and improvement project. In a comprehensive conclusion, the applicability of ENERWATER was confirmed based on sewage statistics data and labeling can be used to set priorities for the energy diagnosis and improvement project.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.1
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• pp.1-14
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• 2015

This study investigates the impact of enhanced regional meteorological fields on improvement of wind energy forecasting accuracy in the southwestern coast of the Korean Peninsula. To clarify the effect of detailed surface boundary data and application of analysis nudging technique on simulated meteorological fields, several WRF simulations were carried out. Case_LT, which is a simulation with high resolution terrain height and land use data, shows the most remarkable accuracy improvement along the shoreline mainly due to modified surface characteristics such as albedo, roughness length and thermal inertia. Case_RS with high resolution SST data shows accurate SST distributions compared to observation data, and they led to change in land and sea breeze circulation. Case_GN, grid nudging applied simulation, also shows changed temperature and wind fields. Especially, the application of grid nudging dominantly influences on the change of horizontal wind components in comparison with vertical wind component.

• Advanced Composite Materials
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• v.18 no.2
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• pp.121-134
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• 2009

The present study investigated, both experimentally and numerically, the improvement of low-velocity impact damage resistance of carbon fiber reinforced plastic (CFRP) laminates due to through-the-thickness stitching. First, we conducted drop-weight impact tests for stitched and unstitched laminates. The results of damage inspection confirmed that stitching did improve the impact damage resistance, and revealed that the improvement effect became greater as the impact energy increased. Moreover, the stitching affected the through-the-thickness damage distribution. Next, we performed FEM analysis and calculated the energy release rate of the delamination crack using the virtual crack closure technique (VCCT). The numerical results revealed that the stitching affected the through-the-thickness damage distribution because the stitch threads had a marked effect on decreasing both the modes I and II energy release rate around the bottom of the laminate. Comparison of the results for models that contained delaminations of various sizes revealed that the energy release rate became lower as delamination size increased; therefore the stitching improved the impact resistance more effectively when the impact energy was higher.