• KIEAE Journal
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• v.13 no.4
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• pp.55-62
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• 2013

Korea Government have carried out various policies to reduce the energy consumption that cause the global warming and environmental pollution. Energy consumption of buildings in Korea has reached 24% of total energy quantities and energy consumption of apartment has been continuously increasing. It has executed the building energy efficiency rating system and energy performance assessments and certification systems have been in force to save energy consumption of buildings. Therefore, this study tried to asset the energy performance of apartment according to the shapes of unit plan, and then to evaluate the energy performance of apartment according to altering balcony area into living area in the unit plan of apartment and thus, to present the effective unit plan to reduce the energy consumption. According to the results, in case of standard unit plan, the 3Bay and 4Bay unit plans showed more effective energy consumption than the 2Bay unit plan, respectively, 5%, 6%, and in case of extended unit plan, respectively, 2%, 5%. Compared the energy efficiencies of the standard unit plan to the extended unit plan, the standard one showed more effective energy consumption than the extended one, respectively, 2% in case of the 2Bay and 4Bay unit, 5% of the 3Bay unit.

• Journal of Energy Engineering
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• v.28 no.1
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• pp.37-44
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• 2019

Domestic buildings account for 25% of national greenhouse gas emissions and 20% of energy consumption, so energy efficiency improvement of buildings is recognized as the main target of national energy demand management. To improve the energy efficiency of the building, policies are implemented by preparing "zero-energy building national roadmaps" and enhancing the efficiency of national energy demand management through early activation as a result of expansion of the mandatory zero-energy building. Also, there is a growing need to verify the performance of energy savings after the construction is completed. Therefore, methods for evaluating energy performance of buildings should be suggested. This paper aims to develop and present methods for verifying energy performance of Zero Energy School, which can be applied internationally, by visiting domestic schools on-site at the same time as international standards and guidance analysis.

• Journal of the Korean Solar Energy Society
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• v.26 no.4
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• pp.39-45
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• 2006

The decrease in the summer peak electric load in our country is very important. The government has arranged and implemented a lot of support policies and statutes to decrease the peak electric load. And the ice thermal energy storage system is known as one of the alternatives. The purpose of this paper is to evaluate the efficiency and thermal characteristics of the closed ice thermal energy storage system using screw capsules. The measured thermal energy storage density is about 18.4 USRT-h/m3 (=232.9 MJ/m3), which is higher than 13.0 USRT-h/m3 (=164.6 MJ/m3), a low criterion of normal performance. And The efficiency of the discharging process and the total energy utilization is 96.2% and 2028.4 kcal/kWh respectively.

• Membrane Journal
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• v.24 no.5
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• pp.386-392
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• 2014

Two commercial membranes (porous membrane and cation exchange membrane) were evaluated as a separator in the Zn-Br redox-flow battery (ZBRFB). The performance properties of ZBRFB were test in the current density of $20mA/cm^2$. The electromotive forces (OCV at SOC 100%) of ZBRFB using SF-600 (porous membrane) and Nafion 117 (cation exchange membrane) were 1.87 V and 1.93 V, respectively. The cycle performance of ZBRFB using each membrane was evaluated during 7 cycles. The performance of ZBRFB using SF-600 membrane was 89.76%, 83.46% and 74.88% for average current efficiency, average voltage efficiency and average energy efficiency, respectively. The performance of ZBRFB using Nafion117 membrane was 97.7%, 76.33% and 74.56% for average current efficiency, average voltage efficiency and average energy efficiency, respectively.

• Preventive Nutrition and Food Science
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• v.1 no.2
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• pp.239-243
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• 1996

Three hundred and twenty-four 1 day old chicks were used to determine the effects of fat source and energy to protein ratio on growth performance , carcass composition and the efficiency on nutrient utilization. Chicks were assigned. in a completely randomized design, to 3*3 factorial arrangement of treatments. Chicks received one of three fat sources (n0 fat, tallow, corn oil) and one of three energy to protein ratios(16, 14 and 12kcal ME/g CP). All diets were formulated to be isocaloric(3.2Mcal ME/kg diets) using published ME values for the diet ingredients. Addition of tat to the diet increased ADG, average daily feed intake, and gain to feed, Chicks fed diets containing fat had increased percentage body DM and ether extract(EE), but percentage CP was not different, Chicks fed diets containing fat had increased efficiency of protein and energy deposition. Addition of fat ad either fallow or corn oil yielded similar results. Reducing the energy to protein ratio of the diet did not affect ADG or gain to feed, but tended to decrease average daily feed intake(p=0.80), as well as resulting in linear(p<0.05) reductions in body percentage DM., EE and also total EE. Increasing the energy to protein ratio did not affect percentage or total body Cp. Adding fat to poultry diets improved growth performance and the efficiency of growth chicks. Decreasing the energy to protein ratio did not affect growth performance, but reduced EE in the body of Chicks.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.126-127
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• 2016

The Korean government has developed and strengthened energy related regulations to pursue eco-friendly buildings since 1979. However, required design standards for energy based quantitative studies focused on energy performance in existing buildings are meagered. Therefore in this study, required energy performance by design standards for energy are analyzed. And a energy performance by retrofits for insulation improvement is studied using energy simulations.

• Transactions of Materials Processing
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• v.32 no.3
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• pp.153-159
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• 2023

This paper presents the optimal design of a heating system using radiant heating elements for application in smart farms. Smart farming, an advanced agricultural technology, is based on artificial intelligence and the internet of things and promotes crop production. Temperature and humidity regulation is critical in smart farms, and thus, a heating system is essential. Radiant heating elements are devices that generate heat using electrical energy. Among other applications, radiant heating elements are used for environmental control and heating in smart farm greenhouses. The performance of these elements is directly related to their electrical energy consumption. Therefore, achieving a balance between efficient electrical energy consumption and maximum heating performance in smart farms is crucial for the optimal design of radiant heating elements. In this study, the size, electrical energy supply, heat generation efficiency, and heating performance of radiant heating elements used in these heating systems were investigated. The effects of the size and electrical energy supply of radiant heating elements on the heating performance were experimentally analyzed. As the radiant heating element size increased, the heat generation efficiency improved, but the electrical energy consumption also increased. In addition, increasing the electrical energy supply improved both the heat generation efficiency and heating performance of the radiant heating elements. Based on these results, a method for determining the optimal size and electrical energy supply of radiant heating elements was proposed, and it reduced the electrical energy consumption while maintaining an appropriate heating performance in smart farms. These research findings are expected to contribute to energy conservation and performance improvement in smart farming.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.2
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• pp.136-144
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• 2006

Vehicles usually have 3 types of speed pattern like acceleration, travel, and deceleration. It requires much driving energy from engine while accelerating, preserves much kinetic energy by inertia moment at travel speed, and releases the kinetic energy to the air while decelerating by the break system. If we accumulate the kinetic energy while decelerating and reuse the energy at the accelerating stage, then it can elevate the fuel efficiency, reduce the emission and improve the motive power. This paper proposes a hydraulic type energy regenerative system which converts the kinetic energy into hydraulic energy at the stage of deceleration and reuses it at the starting and accelerating stage of vehicles. The test equipment which has the field condition of city bus was prepared to evaluate the performance for energy regeneration. The test results show that both energy regeneration efficiency and fuel efficiency are improved significantly and the emission is reduced notably.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.30 no.4
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• pp.159-166
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• 2018

The Korean fenestration energy consumption efficiency rating system only considers thermal performance of the heat transfer coefficient (U-value) and airtightness excluding optical characteristics of the solar heat gain coefficient (SHGC). This study analyzed annual heating and cooling energy requirements on the middle floor of apartment by optical and thermal performance of windows to evaluate the suitability of the rating system. One hundred and twenty-eight windows were analyzed using THERM and WINDOW 7.4, and energy simulation for a reference model of an apartment house facing south was performed using TRNSYS 17. The results showed that window performance was the main factor in the heating and cooling load. The heating load of the reference model was 539 kWh to 2,022 kW, and the cooling load was 376 kWh to 1,443 kWh. The coefficient of determination ($R^2$) of the heating and cooling loads driven from the SHGC were 0.7437 and 0.9869, which are more compatible than those from the U-value, 0.0558 and 0.4781. Therefore, it is not reasonable to evaluate the energy performance of windows using only the U-value, and the Korean fenestration energy consumption efficiency rating system requires a new evaluation standard, including SHGC.

• Journal of the Korea Society of Computer and Information
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• v.14 no.12
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• pp.17-24
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• 2009

More recently, the Green Computing have become a important issue in all fields of industry. The energy efficiency cannot be over-emphasized. Microprocessor companies such as Intel Corporation design processors with taking both energy efficiency and performance into account. Nevertheless, general computer users typically utilize the CPU overclocking to enhance the application performance. The overclocking is traditionally considered as an evil in terms of the power consumption. In this paper, we present effective CPU overclocking schemes, which raise CPU frequency while keeping current CPU supply voltage for energy reduction and performance improvement. The proposed scheme gain both energy reduction and performance improvement. Evaluation results show that our proposed schemes reduce the processor execution time as much as 17% and total computer system energy as much as 5%, respectively. In addition, our effective CPU overclocking schemes reduce the Energy Delay Product (EDP) as much as 22%, on average.