• Structural Engineering and Mechanics
• /
• 제17권3_4호
• /
• pp.573-591
• /
• 2004

A hybrid control system is presented for seismic-resistant building structures with and without soil-structure interaction (SSI). The hybrid control is a damper-actuator-bracing control system composed of passive and active controllers. An intelligent algorithm is developed for the hybrid system, in which the passive damper is designed for minor and moderate earthquakes and the active control is designed to activate when the structural response is greater than a given threshold quantity. Thus, the external energy for active controller can be optimally utilized. In the control of a multistory building, the controller placement is determined by evaluating the optimal location index (OLI) calculated from six earthquake sources. In the study, the soil-structure interaction is considered both in frequency domain and time domain analyses. It is found that the interaction can significantly affect the control effectiveness. In the hybrid control algorithm with intelligent strategy, the working stages of passive and active controllers can be different for a building with and without considering SSI. Thus SSI is essential to be included in predicting the response history of a controlled structure.

• 한국건설순환자원학회논문집
• /
• 제2권4호
• /
• pp.291-296
• /
• 2014

건축물 에너지 사용량과 온실가스 배출량 감소를 목적으로, 열적 물성 등이 향상된 새로운 단열소재가 개발 사용되는 추세이다. 이중 기존 단열소재의 문제점 (가연성, 처짐, 수분 취약성, 단열성능 저하 등)을 보완한 미네랄 하이드레이트 소재가 새롭게 사용되고 있다. 미네랄 하이드레이트는 건축물 구조체로 사용되는 ALC의 제조방법과 유사하나, 구조체가 아닌 단열소재만으로 사용된다는 특징을 갖는다. 미네랄 하이드레이트 제조를 위해서는 시멘트, 생석회 및 무수석고 등이 사용되며, 무수석고는 전량 수입에 의존하고 있다. 따라서 본 연구에서는 수입대체효과 뿐만 아니라, 폐기물 재활용 측면에서 무수석고를 대체하여 석유제조 공정 부산 탈황석고를 사용하고자 하였다. 탈황석고를 미네랄 하이드레이트 원료로 사용할 경우, 무수석고 전량과 생석회 일부를 대체할 수 있었다. 더불어 탈황석고를 사용한 미네랄 하이드레이트는 기존 무수석고 사용시와 유사한 열적, 물리적 특성도 발현되었다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2014년도 추계학술대회 논문집
• /
• pp.105-106
• /
• 2014

본 논문에서는 디젤발전기와 에너지 저장 시스템, 태양광 발전을 이용한 스마트 그린 빌딩의 하이브리드 에너지 시스템을 제안한다. 빌딩 하이브리드 에너지시스템은 다양한 전력원을 가질 수 있는데 기존의 디젤발전기에 화석연료를 저감할 목적으로 풍력발전시스템이나 태양광발전시스템과 같은 형태의 신재생에너지원들이 연계 운전될 수 있다. 연료소모를 최소화하고 디젤발전기의 느린 출력응답특성으로 인한 계통 전압 불안정화를 보상하기 위해 응답특성이 빠른 배터리와 슈퍼커패시터로 이루어진 에너지저장장치와 태양광발전원과의 연계운전 기술을 제안하고 시뮬레이션 하였다.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
• /
• 제16권1호
• /
• pp.43-53
• /
• 2010

This study purports to investigate the status quo of the environmentally-friendly green healthcare in teaching hospitals through the questionnaire survey. Data were collected from a total of 46 hospitals. The survey results revealed that most teaching hospitals did not meet the global standard of environmentally-friendly green hospitals. Especially, such items as alternative energy system, water recycling, CO2 emission reduction, green building construction, installation of pond or spring were found to be significantly below global standard. Based upon the study results, various strategies for establishing green hospitals were discussed. For example, energy saving design, such as solar heating, natural wind cooling, automatic temperature controller, green material use, wall surrounded by ivy, were recommended. In conclusion, the strategy and evaluation tool developed in the study will provide a good guide for establishing environmentally-friendly green hospitals.

• International Journal of Advanced Culture Technology
• /
• 제8권2호
• /
• pp.260-269
• /
• 2020

The Steam Assisted Gravity Drainage (SAGD) process is an enhanced method to extract oil from bitumen which involves surface and central process facilities. This paper describes the Central Process Facilities (CPF) of SAGD and proposes several retrofit plans to the Heat Exchanger Network (HEN). In this approach, the process integration scheme is applied to estimate the energy saving in HENs, and various cases are modeled in favor of a commercial simulator. Throughout this work, a minimum approach temperature of 10℃ is assumed. The results reveal that, due to the HEN optimization using process integration, the heating and cooling duties can be reduced to 29.68MW and 1.886MW, respectively. Compared with the Husky case, all cases considered in this study indicate a potential reduction of at least 6% in total cost, including investment and operation costs.

• 한국수소및신에너지학회논문집
• /
• 제32권5호
• /
• pp.410-416
• /
• 2021

The initial electrochemical performance of ceramic fuel cell with thin-film electrolyte was evaluated in terms of peak power density ratio, open circuit voltage ratio, and activation/ohmic resistance ratios at 500℃. Hydrogen and air were used as anode fuel and cathode fuel, respectively. The peak power density ratio reduced as ~17% for 40 minutes, which rapidly decreased in the early stage of the performance evaluation but gradually decreased. The open circuit voltage ratio decreased with respect time; however, its time behavior was remarkably different with the reduction behavior of the peak power density ratio. The activation resistance ratio increased as ~15% for 40 minutes, which was almost similar with the time behavior of the peak power density ratio.

• Journal of Electrochemical Science and Technology
• /
• 제13권1호
• /
• pp.148-158
• /
• 2022

The electrochemical CO₂ reduction (ECR) to produce value-added fuels and chemicals using clean energy sources (like solar and wind) is a promising technology to neutralize the carbon cycle and reproduce the fuels. Presently, the ECR has been the most attractive route to produce carbon-building blocks that have growing global production and high market demand. The electrochemical CO₂ reduction could be extensively implemented if it produces valuable products at those costs which are financially competitive with the present market prices. Herein, the electrochemical conversion of CO₂ obtained from flue gases of a power plant to produce diesel and formic acid using a consistent techno-economic approach is presented. The first scenario analyzed the production of diesel fuel which was formed through Fischer-Tropsch processing of CO (obtained through electroreduction of CO₂) and hydrogen, while in the second scenario, direct electrochemical CO₂ reduction to formic acid was considered. As per the base case assumptions extracted from the previous outstanding research studies, both processes weren't competitive with the existing fuel prices, indicating that high electrochemical (EC) cell capital cost was the main limiting component. The diesel fuel production was predicted as the best route for the cost-effective production of fuels under conceivable optimistic case assumptions, and the formic acid was found to be costly in terms of stored energy contents and has a facile production mechanism at those costs which are financially competitive with its bulk market price. In both processes, the liquid product cost was greatly affected by the parameters affecting the EC cell capital expenses, such as cost concerning the electrode area, faradaic efficiency, and current density.

• Computers and Concrete
• /
• 제19권1호
• /
• pp.7-17
• /
• 2017

In Chinese Design Codes, for super high-rise buildings with complex structural distribution, which are regarded as code-exceeding buildings, elasto-plastic time history analysis is needed to validate the requirement of "no collapse under rare earthquake". In this paper, a 117-story super high-rise building is discussed. It has a height of 597 m and a height-width ratio of 9.5, which have both exceeded the limitations stipulated by the Chinese Design Codes. Mega columns adopted in this structure have cross section area of about $45m^2$ at the bottom, which is infrequent in practical projects. NosaCAD and Perform-3D, both widely used in nonlinear analyses, were chosen in this study, with which two model were established and analyzed, respectively. Elasto-plastic time history analysis was conducted to look into its seismic behavior, emphasizing on the stress state and deformation abilities under intensive seismic excitation.From the comparisons on the results under rare earthquake obtained from NosaCAD and Perform-3D, the overall responses such as roof displacement, inter story drift, base shear and damage pattern of the whole structure from each software show agreement to an extent. Besides, the deformation of the structure is below the limitation of the Chinese Codes, the time sequence and distribution of damages on core tubes are reasonable, and can dissipate certain inputted energy, which indicates that the structure can meet the requirement of "no collapse under rare earthquake".

• 한국건설관리학회논문집
• /
• 제18권1호
• /
• pp.74-82
• /
• 2017

2011년부터 온실가스 에너지 목표관리제와 같은 국가적 온실가스 감축 규제가 대학에도 적용되기 시작하면서 2000년대 급속한 증가를 보이는 것으로 알려졌던 대학의 온실가스 배출량은 2011년 이후 안정세 및 하락세를 보여 오고 있다. 따라서, 온실가스 배출 규제의 시행을 계기로 대학사회가 온실가스 에너지에 대한 관리를 강화하고 있고 그 효과가 나타나고 있다고 이야기할 수 있게 되었다. 특히, 보다 강력한 제도적 속성을 지닌 배출권거래제 시행 준비 시기에는 총량이 줄어드는 결과를 보이는 등 온실가스 다배출 대학을 중심으로 감소하는 추세로 전환되었다고 평가할 수 있다. 본 연구에서는 개별 대학의 온실가스 감축 활동을 세부적으로 추적하지는 않았지만 온실가스 배출에 영향을 끼치는 주요 활동도 자료를 분석하였고, 그 결과 대학의 온실가스 배출이 2011년 이전에는 연구수혜액, 그리고 2013년 이후에는 연면적의 변화가 영향을 주는 것을 확인하였다. 이에, 향후 대학의 온실가스 감축 목표 설정 원단위는 연면적을 기준으로 하는 것이 바람직하다고 판단되며, 보다 체계적인 대학의 온실가스 감축을 지원하기 위한 면적 단위 온실가스 배출량의 기준 수립과 관련 정보 공유가 필요하다고 할 수 있다.

• 한국해양공학회지
• /
• 제31권2호
• /
• pp.121-129
• /
• 2017

The present study numerically investigated the influence of the waveform distribution on the tsunami-vegetation interaction using a non-reflected wave generation system for various tsunami waveforms in a two-dimensional numerical wave tank. First, it was possible to determine the wave attenuation mechanism due to the tsunami-vegetation interaction from the spatial waveform, flow field, vorticity field, and wave height distribution. The combination of fluid resistance in the vegetation and a large gap and creates a vortex according to the flow velocity difference in and out of the vegetation zone. Thus, the energy of a tsunami was increasingly reduced, resulting in a gradual reduction in wave height. Compared to existing approximation theories, the double volumetric ratio of the waveform increased the reflection coefficient of the tsunami-vegetation interaction by 34%, while decreasing the transfer coefficient and energy attenuation coefficient by 25% and 13%, respectively. Therefore, the hydraulic characteristics of a tsunami is highly likely to be underestimated if the solitary wave of the approximation theory is applied for the tsunami.