• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.75-80
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• 2008

Recently, Energy savings in buildings has received much attention in response to the increased needs for global warming and better comforts of the occupants in apartment housing. This study proposes the method which uses the sun control window film to reduce the cooling load and heating load improving the thermal performance of the building and it improves an energy efficiency. The film which used in actual measurement has a low shading coefficient and a solar energy transmission. so we measured the surface temperature of the triple Low-e glazing system used and inside temperature according to the change of outside temperature and solar energy to study thermal performance evaluation. As a result, it was helpful to use window film insulation to reduce inside temperature in summer and to keep room warm in winter.

• KIEAE Journal
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• v.12 no.4
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• pp.41-46
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• 2012

In Korea, Apartment houses recently occupy over 80% of all buildings. Ground source system has to be designed to consider feature of apartment house. Most apartment houses use PHC pile to get a bearing power of the soil. Therefore, the purpose of this study is to evaluate performance of ground source heat pump system utilizing energy pile under apartment. Object of experiment is low-energy experiment apartment in Song-do and Energy Pile are applied to 80%, 100% energy reduction model for heat-source. First, performance evaluation of Energy Pile geothermal system was done during summer season. As a result, The COP(coefficient of performance) about geothermal heatpump was approximately 5-6 while cooling. In winter season, Long experiment was performed because it was very important to evaluate ground condition for long time. During heating experiment, Indoor room set temperature was $20^{\circ}C$ and kept constant by heating. Coefficient of performance for heat pump and overall system was calculated. It was 3.5-4.5 for COP and 2.5-3.7 for system COP.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.6
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• pp.810-818
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• 2011

This paper analyzed the suitability about the isolation performance criteria which was based on human impedance and effect of current in IEC 60479-1 on the safety of human being was examined. The method of evaluation by megger and DC voltmeter was analyzed. The differences of isolation performance according to design of high-voltage system were analyzed. The factors which affect the insulation performance were analyzed for HFCV, EV, HEV, etc. through analysis of the isolation performance evaluation method. Finally, design for improved isolation performance was proposed.

• Journal of the Korean Solar Energy Society
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• v.21 no.4
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• pp.55-62
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• 2001

A parabolic dish concentrator used in a high temperature application of solar energy tracks the sun's movement by two axis sun tracking system. In such a system, sun tracking performance affects the system efficiency directly. Generally the higher the tracking accuracy is, the better the system performance is. A large number of parabolic dish type concentrators has been developed and implemented in the world. However none of them clearly provided a qualitative method of how the accuracy of the sun tracking system can be evaluated. The work presented here is the evaluation of sun tracking performance of parabolic dish concentrator, which follows the sun's movement by the sensor, using a computer vision system. We install a camera on the parabolic dish concentrator. While the concentrator follows the sun, sun's images are captured continuously. Then the performance of sun tracking system was evaluated by analyzing the variation of the position of the sun in the captured images.

• ETRI Journal
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• v.46 no.3
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• pp.432-445
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• 2024

This paper demonstrates improved throughput and energy efficiency of wireless communications by exploiting nonorthogonal multiple access (NOMA), multiple input-multiple output (MIMO), and radio frequency energy harvesting (EH) technologies. To assess the performance of NOMA MIMO communications with EH (MMe), we consider the nonlinear characteristics of EH devices and propose explicit expressions for throughput and outage probability. Based on our results, the system performance is significantly mitigated by EH nonlinearity and is considerably improved by increasing the number of antennas. Additionally, by appropriately adjusting the system parameters, our NOMA MMe innovation can avert complete outages while optimizing system performance. Moreover, the results demonstrate the superiority of the NOMA MMe over its orthogonal multiple access MMe counterparts.

• Journal of the Korean Solar Energy Society
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• v.26 no.4
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• pp.9-16
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• 2006

Geothermal-energy has been getting popular as a natural energy source for green buildings these days. Public building with gross area more than $3000m^2$, planned after March, 2005, should spend about 5% of total building cost for equipment run by natural energy source (e.g. geothermal, solar heat, solar power, etc) according to renewable energy promotion law in Korea. As a result geothermal-energy using heat pump system is emerging as a effective alternative for realistic and economic plan although design guidelines and construction code for the system is in progress and technical data is far from sufficient. The quantitative analysis on the performance of geothermal-energy using heat pump system is insufficient for appropriate design of it. In this paper, cooling performance of geothermal-energy using heat pump system of residential and retail etc. mixed-use building has been analyzed on the basis of temperature comparison between inlet and outlet of heat exchangers of the operating system. Additionally, dry-bulb temperature and relative humidity have been measured and analyzed together as an index of indoor thermal environment.

• Journal of the Korean Solar Energy Society
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• v.32 no.3
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• pp.114-122
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• 2012

Vertical closed-loop ground source heat pump systems(GSHP) have been installed widely in Korea since it can extract moderate temperature level of geothermal heat in a small area. As a ground heat exchanger, a vertical closed -loop type with brine circulation is mostly preferred since it is simple and less harmful to ground environment. However, it requires a secondary heat exchange loop between the refrigerant in a heat pump and the brine. By adding a geothermal heat exchanger in the secondary heat exchange loop, circulation pumps should be attached and the temperature difference between refrigerant and ground is increased, which are important parts of performance degradation. In this paper, annual and seasonal performances of direct expansion(DX) geothermal heat pump were estimated mathematically as an alternative of classical indirect geothermal heat pump based on the annual performance evaluation. As results, DX geothermal heat pump showed 43% higher annual performance than the classical U-tube geothermal heat pump.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.5
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• pp.59-67
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• 2018

G-SEED's evaluation of existing buildings is an important point because the energy consumption and CO2 emissions of existing buildings are continuously increasing due to the aging of buildings over time. However, as G-SEED certification is concentrated on new buildings and the standards are not yet available, we will make improvements to evaluate the existing buildings of G-SEED. In order to improve G-SEED for EB, two research procedures were carried out. First, LEED EBOM and LEED for NC compare and analyze evaluation items and methods, and LEED EBOM focuses on evaluation of existing buildings. Second, we analyzed the certification evaluation contents of eight domestic LEED EBOM accredited buildings and obtained items that can be applied or need to be applied when revising G-SEED for EB. LEED EBOM is focused on improving the performance and utilization of data that track and manage the energy and environmental effects of building operations. As a result of the case analysis, the evaluation of G-SEED for EB requires quantitative evaluation items such as environmental management of buildings, energy performance status of building, improvement plan and improvement of performance according to tracking value. Although G-SEED for EB is not structured yet and there are few cases of certification, it is expected that quantitative evaluation of existing buildings will be made through continuous research.

• International Journal of High-Rise Buildings
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• v.1 no.3
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• pp.195-201
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• 2012

Today, a great effort to develop PBSD procedure to be utilized in Korea is given by domestic structural engineers, academics, and governmental organizations. After Great East Japan Earthquake (2011) took place, lots of clients in Korea became to concern of their buildings so that requests of seismic performance evaluation and seismic rehabilitation for existing buildings have been gradually increased. Such interests in seismic events initiated a rapid development of a series of guidelines for seismic performance evaluation and seismic performance enhancement. For new buildings, however, design guidelines for PBSD are yet well prepared in Korea and prescriptive design methods are dominant design procedure still. Herein, seismicity demands used in seismic performance evaluation and some important design parameters in NLRH are introduced. Some project examples for seismic performance evaluation and rehabilitation applying passive energy dissipation devices are also described in the latter part of paper.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.6
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• pp.21-29
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• 2014

In this paper examine the characteristics of the generator supplying the most significant electrical energy in some parts required to drive the vehicle, and it is focused on to fabricate a performance evaluation unit for developing alternator with better performance. Through performance tests in accordance with the electrical load of alternators that is made in Valeo Corp. and Denso Corp., which are currently applied by H Corp., the fabricated performance evaluation unit has measured the power generation amount of the electrical energy supplied from the alternator, and it was analyzed. On the basis of this result, and to understand the flow of electrical energy of the vehicle, furthermore, it is intended to verify the usefulness of the performance evaluation unit which is designed in this paper. In this paper, based on the mechanism of the proposed performance evaluation unit, it will try to learn the convergence technology that can be applied to the design of the performance evaluation unit of other components of the vehicle.