• 전기학회논문지
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• 제56권11호
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• pp.1903-1909
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• 2007

As the electric power industry has been revolutionarily transformed such that the distributed energy resources have been interconnected with power systems and a variety of energy service providers have been appeared, the need of Consumer Energy Portal as a core of two-way communication and service infrastructure between power suppliers and consumers has been gradually increased. Consumer Energy Portal can be thought of as a combination of hardware and software enabling two-way communication between energy service providers and equipment within the consumers' premises or a physical and logical link between consumers' in-building networks and wide-area access networks. In other words, Consumer Energy Portal can make the way the power industry has been traditionally operated the web-based way, enabling two-way interactions between energy service providers and consumers and mutual networking between end users' equipment. Thus, Consumer Energy Portal can be a kind of Service portal that provides new value-added services and efficient power operations that in the past. In this paper, for ESPs' integrated resources management, demand side management and value-added service provision, we have established the two-way access network that can gather real-time metering data using ZigBee technology and control physically networked equipment.

• Earthquakes and Structures
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• 제8권3호
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• pp.511-539
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• 2015

The main objective of this study is to analytically investigate the effectiveness of different strengthening solutions in upgrading the seismic performance of existing reinforced concrete (RC) buildings in Nepal. For this, four building models with different structural configurations and detailing were considered. Three possible rehabilitation solutions were studied, namely: (a) RC shear wall, (b) steel bracing, and (c) RC jacketing for all of the studied buildings. A numerical analysis was conducted with adaptive pushover and dynamic time history analysis. Seismic performance enhancement of the studied buildings was evaluated in terms of demand capacity ratio of the RC elements, capacity curve, inter-storey drift, energy dissipation capacity and moment curvature demand of the structures. Finally, the seismic safety assessment was performed based on standard drift limits, showing that retrofitting solutions significantly improved the seismic performance of existing buildings in Nepal.

• 디지털융복합연구
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• 제12권11호
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• pp.365-372
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• 2014

본 논문에서는 스마트미터를 활용한 건축물의 전력에너지 절감 및 효율화 방안에 대하여 실험하였다. 전력에너지 절감을 위해 개선된 자동역률제어시스템(APFC)을 제안하고, 수요전력의 억제(Demand Control) 방안을 제시하였다. 이는 스마트미터의 ICT 기술을 통하여 실시간 양방향으로 콘덴서 뱅킹과 차단기를 직접 제어함으로써 이루어진다. 개선된 APFC는 콘덴서 뱅킹을 보다 다양화하기 위해 이종 용량의 콘덴서를 직병렬 혼합 결선하여 구성함으로써 구축 비용을 최소화 한다. 상기 기능을 위해 Atmel사의 AVR465를 이용하여 PLC 및 Zigbee 통신기능을 갖는 스마트미터를 설계하였다. 24시간 운영되는 숙박시설에 대하여 테스트한 결과 역률은 95%이상을 유지하였고, 과보상은 발생하지 않았음을 확인할 수 있었다.

• 토지주택연구
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• 제1권1호
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• pp.27-34
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• 2010

본 연구에서는 그린 홈의 보급확대와 평가기법 개발을 목적으로 하고 있다. 구체적으로는 기 조사된 실측 데이터를 기본으로 시뮬레이션 결과 값의 보간 및 설비시스템의 교체에 따른 효과 검토를 통하여 에너지 절감량 및 이산화탄소 배출 삭감량 평가 프로그램을 개발하였다. 또한, 그린 홈의 보급확대에 따른 비용 검토를 통하여 그린홈을 건설하는 사업자에게는 지방세법 개정에 따른 취등록세 감면 등의 지원대책을 수립하였다.

• Wind and Structures
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• 제35권6호
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• pp.385-394
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• 2022

The energy demand of the world is increasing rapidly, mainly using fossil energy, which causes environmental damage. The wind is free and clean energy to solve the environmental problems. Thailand is one of the developing nations, and the majority of its energy is obtained from petroleum, natural gas and coal. The objective of this study is to test the characteristics of wind energy at Khon Kaen in Thailand. The wind measurement tools, the 3-cup anemometers to measure wind speed, and wind vanes to measure wind direction, were mounted on a wind tower mast to record wind data at the heights of 60, 90 and 120 meters above ground level (AGL) for 5 years between January 2012 and December 2016. The results show that the annual mean wind speeds were 3.79, 4.32 and 4.66 m/s, respectively. The highest mean wind speeds occurred in June, August and December, in order, and the lowest occurred in September. The majority of prevailing wind directions were from the North-East and South-West directions. The average annual wind shear coefficient was 0.297. Furthermore, five wind turbines with rated power from 0.85 to 4.5 MW were selected to estimate the wind energy output and it was found that the maximum AEP and CF were achieved from the low cut-in speed and high hub-height wind turbines. This important information will help to develop wind energy applications, such as the plan to produce electricity and the calculation of the wind load that affects tall and large structures.

• Structural Engineering and Mechanics
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• 제86권5호
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• pp.589-605
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• 2023

This paper investigates the ductility demands of steel frames equipped with self-centring fuses under near-fault earthquake motions considering multiple yielding stages. The study is commenced by verifying a trilinear self-centring hysteretic model accounting for multiple yielding stages of steel frames equipped with self-centring fuses. Then, the seismic response of single-degree-of-freedom (SDOF) systems following the validated trilinear self-centring hysteretic law is examined by a parametric study using a near-fault earthquake ground motion database composed of 200 earthquake records as input excitations. Based on a statistical investigation of more than fifty-two (52) million inelastic spectral analyses, the effect of the post-yield stiffness ratios, energy dissipation coefficient and yielding displacement ratio on the mean ductility demand of the system is examined in detail. The analysis results indicate that the increase of post-yield stiffness ratios, energy dissipation coefficient and yielding displacement ratio reduces the ductility demands of the self-centring oscillators responding in multiple yielding stages. A set of empirical expressions for quantifying the ductility demands of trilinear self-centring hysteretic oscillators are developed using nonlinear regression analysis of the analysis result database. The proposed regression model may offer a practical tool for designers to estimate the ductility demand of a low-to-medium rise self-centring steel frame equipped with self-centring fuses progressing in the ultimate stage under near-fault earthquake motions in design and evaluation.

• KIEAE Journal
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• 제14권3호
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• pp.23-29
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• 2014

With high acknowledgements of environmental conservation and energy saving, many architectural technologies using renewable energy have been recently applied at buildings which take about 20% of total energy consumption. Among renewable energy sources, the photovoltaic is considered as the most highly potential one due to advantages of infiniteness and cleanliness. Also, projects to install renewable energy systems have been continuously performed at deteriorated educational facilities as energy efficient remodeling projects or green school projects by the Korean government. This paper proposes appropriate capacities by school level on installing photovoltaic systems at deteriorated school buildings, based on the balance of annual electricity power demand and supply between buildings and systems. Using the Visual DOE program and Merit program, the appropriate installment capacity of photovoltaic system turned out be 40kWp at elementary school building and 60kWp at middle and high ones. In addition, annual energy use proved to be reduced by 20.2% at elementary school, 26.9% at middle school, and 21.0% at high school by installing photovoltaic systems with the appropriate capacities.

• 대한기계학회논문집B
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• 제22권11호
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• pp.1547-1554
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• 1998

The object of this study was to develop an economic assessment program for the optimal design of the cogeneration systems composed of combining engine, generator, waste heat recovery exchanger, absorption chiller, and boiler, etc. The energy demand categorized by electric power, heating, cooling and water supply was determined by statistical data of the existing cogeneration systems. An economic assessment was performed by comparing the total cost of cogeneration system with that of non-cogeneration system. The total cost was evaluated by adding initial investment to operational cost considering efficiency of equipment, cost of equipment, fuel and electricity. To confirm the validity of the developed program, a hotel building with an area of $127,960m^2$ was selected, and the simulated results were compared with the measured data. The difference between the simulated and the measured values for the selected hotel building was approximately 12% for annual electric consumption.

• 조명전기설비학회논문지
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• 제27권5호
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• pp.18-25
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• 2013

Various DSM (Demand Side Management) programs have been developed and carried out to use the limited energy resources of human-beings reasonably. LED lighting is one of essential DSM programs and the development of technologies is ongoing vigorously. Recently, one-person households have been increased and the electricity consumption pattern is different with conventional households because residents live as a single. On the other hand, owners of the one-person households tend to not prefer to install high efficient appliances due to the cost increasement. Therefore, the existing DSM subsidy programs should be revaluated so that the owners decide to install high efficient appliances.

• 한국태양에너지학회 논문집
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• 제35권4호
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• pp.17-24
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• 2015

The formation of heat islands causes high energy demand for space cooling and peak cooling loads in conditioned buildings. High-temperature fluctuations on a building roof may cause mechanical stress and increase surface deterioration. Thermal energy storage (TES) systems using microencapsulated phase-change materials (MPCMs) have been recognized as one of the most advanced energy technologies for enhancing the energy efficiency and sustainability of buildings. In this study, we prepared MPCM/paint composites for mitigating the heat island effect and reducing peak temperature. In addition, we carried out thermal and physical analysis of prepared MPCM composite samples by means of SEM, FTIR spectroscopy, DSC, and TGA. Further, we evaluated the dynamic heat transfer performance of heat-storage tiles painted with 10 g of heat-storage paint. From the obtained results, we deduced that MPCM/hydrophilic paint composites are more applicable to various fields, including the building sector, than MPCM/hydrophobic paint composites. On the basis of SEM and FTIR spectroscopy results, we concluded that materials with hydrophilic properties are more compatible with MPCMs than those with hydrophobic properties. In addition, DSC analysis results revealed that MPCM/hydrophilic paint composites have better compatibility, higher latent heat capacity, and better thermal properties than other composites. TGA results showed that hydrophilic-paint-based composites have higher thermal durability than hydrophobic-paint-based composites. Finally, a lot of MPCM-loaded heat-storage tiles showed lower peak temperatures at all measurement positions.