• Smart Structures and Systems
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• 제10권3호
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• pp.193-207
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• 2012

New insights into our previously proposed hybrid-type method for vibration control are highlighted in terms of energy analysis, such as the assessment of energy efficiency and system stability. The hybrid method improves the bang-bang active method by combining it with an energy-recycling approach. Its simple configuration and low energy-consumption property are quite suitable especially for isolated structures whose energy sources are strictly limited. The harmful influence of the external voltage is assessed, as well as its beneficial performance. We show a new chattering prevention approach that both harvests electrical energy from piezoelectric actuators and eliminates the displacement-offset of the equilibrium point of structures. The amount of energy consumption of the hybrid system is assessed qualitatively and is compared with other control systems. Experiments and numerical simulations conducted on a 10-bay truss can provide a thorough energy-efficiency evaluation of the hybrid suppression system having our energy-harvesting system.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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• pp.156-161
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• 2011

In case of newly constructed buildings, the construction type is almost Curtain-wall system or large window in building skin. However, these kind of buildings have problems with regulations on building energy efficiency. And national regulations on building energy efficiency limit only the V-factor of window(except infiltration), it is hard to predict energy consumption of Curtain-wall buildings which gain large solar energy in summer. In this study, the influence of LSG(Light to Solar Gain) on energy performance was theoretically analyzed with simulation. LSG is the value of VLT divide SHGC and represents the optical performance of the glass or glazing. The Window & Therm program developed in LBNL was used to analyze window systems and EnergyPlus was used to building energy. Cases of glazing are three types; single coated Low-e clear glazing, tripple coated Low-e clear glazing, tripple coated Low-e tinted glazing. The results of this study are follows; 1) The building energy consumption of Alt-l, 2, 3 were about 300, 253, $259kWh/m^2{\cdot}yr$ respectively. Therefore, improvement of LSG could save the energy up to 16%. 2) The saved energy could be converted 1 billion won as annual benefit of total energy costs 3) SHGC and LSG more influence on cooling energy than heating energy in office buildings.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.166-167
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• 2014

Recently, in according to increase cognizance of energy and resources exhaustion, renewable energy system is received attention. In particular, ground heat pump system(GSHP) utilizing annually stable ground temperature for energy saving have been attracted in many buildings. However, GSHP system have disadvantage due to increase of initial installation and boring cost. In this study, in order to reduce the initial cost and to supply ground heat pump system into small scale house, an unit-type ground heat exchanger was developed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.122-122
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• 2009

Development of renewable energy is promoted to achieve sustainability. So researchers are seeking and developing a new, clean, safe and renewable energy. Fuel cell energy and solar cell energy are expected to be one of the solutions. The emissions of fuel cell is low, the by-product is low, the by-product is only pure water. This paper presents the efficiency of the hybrid system organized with fuel cell and solar cell in faraday law.

• 조명전기설비학회논문지
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• 제28권9호
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• pp.89-98
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• 2014

A diagnostic fluoroscopy X-ray system uses a 32kW or greater X-ray generator for obtaining real-time moving images and high-resolution images. Fluoroscopy X-ray systems have to use a high-capacity AC power source to perform long-time low-power fluoroscopy and short-time high-power spot exposure. In this paper, we propose a hybrid type X-ray generator for fluoroscopy X-ray system which can perform fluoroscopy and spot exposure with a low-capacity AC power source and an energy storage device. The characteristics of energy storage devices are compared and each energy storage device is modelled to equivalent circuit. And the characteristics of available energy are analyzed as a function of output voltage and power. A 32kW class hybrid X-ray generator with EDLC as an energy storage device for fluoroscopy X-ray system was constructed, and its validity was verified by means of simulations and experiments.

• Steel and Composite Structures
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• 제20권6호
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• pp.1205-1219
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• 2016

This paper presents a new type of pre-pressed spring self-centering energy dissipation (PS-SCED) bracing system that combines friction mechanisms between the inner and outer tube members to provide the energy dissipation with the pre-pressed combination disc springs installed on both ends of the brace to provide the self-centering capability. The mechanics and the equations governing the design and hysteretic responses of the bracing system are outlined, and a series of validation tests of components comprising the self-centering mechanism of combination disc springs, the friction energy dissipation mechanism, and a large scale PS-SCED bracing specimen were conducted due to the low cyclic reversed loadings. Experimental results demonstrate that the proposed bracing system performs as predicted by the equations governing its mechanical behaviors, which exhibits a stable and repeatable flag-shaped hysteretic response with excellent self-centering capability and appreciable energy dissipation, and large ultimate bearing and deformation capacities. Results also show that almost no residual deformation occurs when the friction force is less than the initial pre-pressed force of disc springs.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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• pp.179-184
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• 2011

The development of new energy has attracted consideration attention due to the high oil price and environmental problems. In advanced country, they have tried to carry out a long range plan for energy. We need to develop new energy for Low Carbon Green Growth in Korea. The building is 30% among ratio of energy consumption in Korea. And in the past, heating energy was high ratio for energy using at home. But recently, the demand for cooling energy keeps growing due to rising average temperature on the earth and improvement of life quality. In this situation, the energy of lake water and ocean water has studied to utilize in advanced country because of low temperature at underwater. But the study for deep water is still a lot left to do. In this study, we analyzed district cooling system and the present condition. Analyzing the deep lake water cooling system in Toronto, we found an application of district cooling system using deep ocean water. Deep lake water uses heat source for district cooling and water source for city in Toronto. So reducing the initial cost, this city had economic effect. When DLWC was applied at existing building, the heat exchanger was installed instead of cooling tower and refrigerator. And the heat exchanger used to connect main pipe with cool water on city. System using deep ocean water can be applied as a similar way to supply cool water from lake to building.

• 한국수소및신에너지학회논문집
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• 제24권5호
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• pp.393-400
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• 2013

The air supply system has a significant effect on the efficiency of polymer electrolyte membrane fuel cell (PEMFC) systems. The performance and efficiency of automotive PEMFC systems are greatly influenced by their air supply system configurations. This study deals with the system simulation of automotive PEMFC systems using MATLAB/Simulink framework. In this study, a low-pressure operating PEMFC system adopting blower sub-module (turbo-blower) is modeled to investigate the effects of stack operating temperature and air stoichiometry on the parasitic power and efficiency of automotive PEMFC systems. In addition, the PEMFC net system efficiency and parasitic power of air supply system are mainly compared for the two types (low-pressure operating and high-pressure operating) of automotive PEMFC systems under the same net power conditions. It is suggested that the obtained results from this system approach can be applied for establishing the novel operating strategies for FC vehicles.

• 한국정보전자통신기술학회논문지
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• 제12권3호
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• pp.273-281
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• 2019

국가 총에너지 소비량 중 건축물에서 소비하는 에너지는 전체의 10% 이상을 차지고 있다. 이러한 이유로 우리나라는 2025년부터 제로에너지 건물 의무화 정책을 채택하였고, 결국 건축물 에너지 절감 기술에 대한 연구가 요구되고 있다. 건축물 중 빌딩의 에너지 소비 형태를 분석해보면 조명 및 냉난방 에너지가 전체 에너지 소비량의 60% 이상을 차지하고 있는데, 이는 태양광 취득률 및 창문의 개폐 운용과 직접적인 연관이 있다. 본 논문에서는 건축물에너지 관리시스템에 취득 정보를 전송하기 위한 창호용 저전력 IoT 센서 모듈을 개발하기 위해 연구를 진행하였다. 이 모듈은 외부 환경 및 창문 개폐 상태 정보를 실시간으로 빌딩 에너지 관리 시스템에 전송하여 능동적으로 에너지 절감 조치를 취할 수 있게 네트워크를 구성하였다. 모듈에 사용되는 전력은 하베스트 에너지 중 태양광 발전을 이용한 독립적인 전원으로 설계하였다. 전원은 Buck 컨버터를 적용하여 MPPT 제어를 통해 리튬이온 배터리에 4V로 충전하는 방식으로 효율은 약 85.87%이다. 통신은 WiFi 방식을 적용하여 실시간으로 전송할 수 있도록 구성하였다. 모듈의 소비전력 저감을 위해 하드웨어 및 소프트웨어 측면에서 분석하여 저전력 IoT 센서 모듈을 구현에 대한 연구를 진행하였다.

• 한국태양에너지학회 논문집
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• 제32권3호
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• pp.19-25
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• 2012

About supply and demand to see that you need to match, the limitations of wind power capacity is low demand and the commitment of the general generator will exist between the minimum generation. if the turbine's output can be controlled, The limitation of wind power capacity will be adopted based on instant power generation. Namely, The minimum limits of wind power generation based load operation by calculating the amount that is higher than if the output should be restricted to highest operation. in this paper, we committed to the demand for low enough that the combination of the general generator of wind power capacity to accommodate the operation of determining whether the limit is intended to. For this, power system analysis program PSS/E was used, Jeju system by implementing the model simulations were performed.