• Korean Journal of Organic Agriculture
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• v.31 no.4
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• pp.461-468
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• 2023

Supplying an appropriate amount of feed is an economical and environmentally friendly by increasing the nutrient digestibility of livestock and reducing nutrients released from overfeeding. Therefore, this study was conducted to determine the nutrient digestibility according to dietary feeding levels of Hanwoo steers. Three treatments in feeding trial were used feeding amount based on the maintenance energy level of the Korean feeding standard for Hanwoo (2022): 100% (control, CON), 140% (treatment 1, TRT1), and 190% (treatment 2, TRT2). The experiment was designed in replicate 3×3 balanced Latin square designs using six Hanwoo steers. In this study, energy value was predicted according to treatment groups. In addition, nutrient digestibility and energy value were measured through a feeding trial to Hanwoo steers. All energy values, including total digestible nutrients and digestible energy, were predicted to decrease linearly with increasing feeding levels. TRT2 showed lower digestibility than CON for dry matter, crude protein, non-fiber carbohydrates, and total digestible nutrients in the feeding trial (p<0.05). However, there was no significant difference between CON and TRT1. Total digestible nutrients (TDN) and digestibility of feed are set based on the maintenance energy. However nutrient digestibility and TDN decreased when feeding level increased by more than 190% compared to maintenance energy in this study. Therefore, it is necessary to correct the TDN by considering the feeding level when mixing the feed.

• Journal of the Korean Solar Energy Society
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• v.33 no.1
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• pp.96-105
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• 2013

This study aims to investigate the energy performance of apartment in respect of complex design, building type and generation house layout and finally to produce the guide line for energy saving design. To grasp the present condition and problem about this subject, apartment building types were examined and representative types were extracted. Considering azimuth angle, private area, and generation number, building type of the subject apartment was classified in detail, energy simulation was conducted, and the effect to energy cost was compared. In the research, using VE energy simulation program, the heating and cooling load were calculated and converted to energy cost. It is expected that this analysed results will be basic data for the more integrated study. Research consequence can be summarized as follow: 1) Energy cost is compared according to several azimuth in plank '一' type apartment. As the results, calculated gas cost is the best in $49^{\circ}$, but total cost is in $-31^{\circ}$. 2) Apartment buildings of tower types are compared, it is resulted that 'Y' type (azimuth $-7^{\circ}$, $-20^{\circ}$) is the best in gas cost, but the total cost is worst because of high cooling load.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.185-190
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• 2009

Due to the building energy consumption of total energy consumption of Korea takes over 24%, economizing building energy and using renewable energy resources is being required. To suggest the prototype of zero energy house of country house, the passive systems and active systems are applicated and simulated. In case of wall insulation system is applicated, the heating load of building is reduced. Also, clear triple pair glazing system reduced 2.1% of heating load of building. The amount of reducing heating load by infiltration is depending on the Heating system. In this model, the 0.3ACH made 14.6% saving on heating load from base infiltration 0.82ACH. The solar thermal system of active system could save 80% of DHW and PV system supplies electric power more than average consumption of year. Through the optimum process, the end use of zero energy house of country house is 36kWh/m2.yr and total energy consumption is reduced about 74.2%.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.762-767
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• 1991

To make electromechanical total artificial heart implantable inside the body, transcutaneous energy transmission system was designed and simulated by using PSPICE program. The fabricated system was evaluated by using Mock circulation system and showed comparable performance with the D.C power supply

• Proceedings of the SAREK Conference
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• 2004.06a
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• pp.19-19
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• 2004

• Journal of the Korean Solar Energy Society
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• v.31 no.5
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• pp.85-90
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• 2011

The effects of $CO_2$ ppm in atmosphere on the values of the total emissivity are studied. The predictions by several methods are compared. The predicted value differences between modified Kondratyev model and Hottel model are the smallest with in the range of values tested. The $CO_2$ ppm is varied from 300 ppm to 600 ppm. By Wide Band model, the total emissivity increases with increasing density-path length product rather linearly up to 0.1 g/$cm^2$. For given $CO_2$ ppm, the total emissivity increases as the air thickness increases. The same is true for both temperature and pressure increase. The temperature range tested is 220 to 300 K. Around 260K, the total emissivity is less sensitive with increasing temperature than with decreasing temperature. The pressure is varied from 0.94 to 1.06 atm. The percentage change of total emissivity with pressure change from 1atm is at most the percentage change of the pressure.

• Journal of the Korean Solar Energy Society
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• v.32 no.2
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• pp.50-57
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• 2012

Recently the renewable energy has been used widely and the importance of renewable sources is bigger than before. And the government enforced a law to the public buildings to install the renewable energy facilities. The capacity of facilities was 5% of total construction cost until April 13, 2011. Since then, the government changed the law from 5% of total construction cost to 10% of predicted energy usage for the resonable use of the renewable energy facilities. In this study, the comparative analysis is conducted according to the law to the building installed PV system through the Energy Plus simulation. And the method for improving renewable energy supply ratio was analyzed using existing PV array. Adjusting the PV array angle is the best way to generate more electric power without additional fee. When applying the month optimum angle, 3,600kWh of electric power are more generated compared to the existing angle.

• KIEAE Journal
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• v.13 no.1
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• pp.57-63
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• 2013

Building Energy Efficiency Rating system was enforced in 2001 to enhance spreading high-energy performance and saving buildings. It was only for the new apartments, but expanded to new office buildings in 2010, and moreover, government offices require 1st grade of Building Energy Efficiency Rating system. Green Building Act, which is established to reduce the emissivity of carbon dioxide by reducing building energy consumption, will be enforced in 2013, and new apartments and office buildings will be subjected to it. Henceforward, it will extend to other types of buildings and will be phased in. In general, pumps and fans consume approximately half of the air-conditioning energy consumption, and about a quarter of the total building energy consumption when office buildings have total floor area of more than 10000 square meters. This study analyzed the energy demand when applying VAV(Variable Air Volume) and VWV(Variable Water Volume) System to reduce energy returns of the pumps and the fans by ECO2, which is a computer simulation program used for Building Energy Efficiency Rating system.

• KIEAE Journal
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• v.16 no.2
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• pp.11-16
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• 2016

Purpose: International efforts to save Earth's environment against global warming and environmental pollution have been made in many countries. Energy consumption of buildings has been continuously increasing, and it has been over 40% of total energy consumption in the world. Energy consumption of buildings in Korea reaches 24% of total energy consumption. So, Korea government has executed building energy rating systems to control energy consumption of buildings. Method: This study was carried out to evaluate the energy performance of apartment unit plans according to converting balconies into living areas. For the study, six types of input models were made. Two input models(SP1 and SP 2) were the standard units that balcony areas were not converted into living areas, and four ones(EP 1, EP 2, EP 3 and EP 4) were the extended unit plans that balcony areas were turned into living areas. All of them were simulated with ECO2 software to assess building energy efficiency. Result: According to the results, the energy performance of the EP 2 and EP 4 models were 21. 8% higher than SP 1 model and 9.2% higher than SP 2 model.

• Advances in Energy Research
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• v.5 no.3
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• pp.207-217
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• 2017

Energy consumption in agriculture is responsible for greenhouse gas emission but it can be reduced after efficient utilization of energy inputs. Therefore, the present study aims for the estimation of energy efficiency and extent of greenhouse gas reduction after benchmarking of inefficient farms in off-season tomato in Punjab province of Pakistan. Primary data were collected from 70 farmers with simple random sampling. By using data envelopment analysis, the average value of technical, pure technical and scale efficiency was 0.80, 0.92 and 0.87, respectively while increasing, constant and decreasing return to scale was observed in 33, 26 and 11 farmers, respectively. Total input energy was reduced by $12,688.91MJ\;ha^{-1}$ (13.89%) if inefficient farms used the energy inputs according to recommendations or benchmarking. A major portion of energy saving comes from fertilizers (68.79%) followed by diesel (15.70%), chemicals (5.91%), machinery (4.37%) and water (4.00%). Total greenhouse gases reduction was $499.17kg\;CO_2\;eq.ha^{-1}$ (14.57%) as a result of improvement in energy efficiency or benchmarking of inefficient farms. Agricultural extension staff should visit the vegetable farms on regular basis and give necessary information about efficient utilization of energy inputs. The government should create awareness about the optimum use of input through seminars and pamphlets.