• Transactions of the Korean hydrogen and new energy society
• /
• v.33 no.6
• /
• pp.636-642
• /
• 2022

The "Hydrogen Economic Activation Road map" was announced in 2019, and hydrogen demand is expected to exceed 470,000 tons per year in 2022 and keep increasing. Under this circumstance, it has become important to understand the greenhouse gas (GHG) emissions associated with various hydrogen production pathways. In this study, the evaluation of life cycle GHG emissions regarding the hydrogen produced as by-product from coke oven gas (COG) in steel mill is conducted. To cover the possible range of operations, three literatures were reviewed and their data of inputs and outputs for the process were adopted for calculation. Life cycle inventories and emission factors were mostly referred to GaBi and Intergovernmental Panel on Climate Change (IPCC) guidelines, respectively. When there are multiple products from a single process, the energy allocation method was applied. Based on these sources and the assumptions, the life cycle emission values of COG-based hydrogen were found to be 3.8 to 4.7 kg/CO₂-eq./kg-H₂.

• Structural Engineering and Mechanics
• /
• v.35 no.5
• /
• pp.571-592
• /
• 2010

An energy-based fatigue life prediction framework was previously developed by the authors for prediction of axial, bending and shear fatigue life at various stress ratios. The framework for the prediction of fatigue life via energy analysis was based on a new constitutive law, which states the following: the amount of energy required to fracture a material is constant. In the first part of this study, energy expressions that construct the constitutive law are equated in the form of total strain energy and the distortion energy dissipated in a fatigue cycle. The resulting equation is further evaluated to acquire the equivalent stress per cycle using energy based methodologies. The equivalent stress expressions are developed both for biaxial and multiaxial fatigue loads and are used to predict the number of cycles to failure based on previously developed prediction criterion. The equivalent stress expressions developed in this study are further used in a new finite element procedure to predict the fatigue life for two and three dimensional structures. In the second part of this study, a new Quadrilateral fatigue finite element is developed through integration of constitutive law into minimum potential energy formulation. This new QUAD-4 element is capable of simulating biaxial fatigue problems. The final output of this finite element analysis both using equivalent stress approach and using the new QUAD-4 fatigue element, is in the form of number of cycles to failure for each element on a scale in ascending or descending order. Therefore, the new finite element framework can provide the number of cycles to failure at each location in gas turbine engine structural components. In order to obtain experimental data for comparison, an Al6061-T6 plate is tested using a previously developed vibration based testing framework. The finite element analysis is performed for Al6061-T6 aluminum and the results are compared with experimental results.

• International conference on construction engineering and project management
• /
• 2007.03a
• /
• pp.625-634
• /
• 2007

Energy-saving is one of important issues in multi-family housing projects in South Korea. According to the study by Yu et al. (2002), the balcony conversion causes energy loss approximately one and a half times. Therefore, it is important to select the economical glass type in the balcony window. In order to identify the most economical glass type of balcony conversion in multi-family housing projects, the most typical type of the multifamily housing projects in the metropolitan area was selected as a candidate project. The selected candidate project has been simulated using ENERGY-10 program to estimate the heat load by the different five types of glasses as well as their life cycle cost analysis (LCCA) using present worth method. Finally, sensitivity analysis has been conducted to determine the most economical glass types under a different discount rate (interest rate) and service life of building.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.21 no.2
• /
• pp.71-78
• /
• 2009

Up until recently, the energy and the economic analysis of a cogeneration system have been implemented by a manual calculation that is based on monthly thermal loads of buildings. In this study, a cogeneration system modeling validation with a detail building energy simulation, eQUEST, for a building energy and cost prediction has been implemented. By analyzing the hourly building electricity and thermal loads, it enables users to decide proper cogeneration system capacity and to estimate more accurate building energy consumption. eQUEST also verified the energy analysis when the heat pump system is integrated with the cogeneration system. The mechanical system configuration benefits from the high efficiency heat pump system while avoiding the building electricity demand increase. Economic analysis such as LCC (Life Cycle Cost) method is carried out to verify economical benefits of the system by applying actual utility rates of KEPCO(Korea Electricity Power COmpany) and KOGAS(KOrea GAS company).

• Nuclear Engineering and Technology
• /
• v.45 no.5
• /
• pp.653-664
• /
• 2013

The design of computer-based instrumentation and control (I&C) systems is determined by the allocation of I&C functions to I&C systems and components. Due to the characteristics of computer-based technology, component failures can negatively affect several I&C functions, so that the reliability proof of the I&C systems requires the accomplishment of I&C system design analyses throughout the I&C life-cycle. On one hand, this paper proposes the restructuring of the sequential IEC 61513 I&C life-cycle according to the V-model, so as to adequately integrate the concept of verification and validation. On the other hand, based on a metamodel for the modeling of I&C systems, this paper introduces a method for the modeling and analysis of the effects with respect to the superposition of failure combinations and event sequences on the I&C system design, i.e. the temporal change of physical structure is analyzed. In the first step, the method is concerned with the modeling of the I&C systems. In the second step, the method considers the analysis of temporal change of physical structure, which integrates the concepts of the diversity and defense-in-depth analysis, fault tree analysis, event tree analysis, and failure mode and effects analysis.

• Journal of Environmental Science International
• /
• v.12 no.6
• /
• pp.643-650
• /
• 2003

We analyzed the amount of environmental loads, and the amount of energy consumption through life cycle assessment from a discharge stage to the ultimate disposal to municipal solid waste in Seoul. We carried out inventory analysis of the amount of environmental loads that made the object range collection, intermediate treatment, and the final treatment, and took into consideration each stage exceptions CO$_2$ and NOx , the amount of SOx discharge, and energy consumption. We applied the data of an object model, and acquisition processed the scale of an object model suitably and applied to it to difficult data using the data of the Yokohama City incineration plant in Japan. The amount of environmental loads per Iton of municipal waste were analyzed CO$_2$ 0.4C-ton, SOx 0.4kg and NOx 0.8kg. Moreover, the amount of energy consumption which is 2.4Gcal was computed.

• Advances in Energy Research
• /
• v.8 no.1
• /
• pp.1-19
• /
• 2022

The application of Photovoltaic (PV) power in the building sector, is expanding as part of the ongoing energy transition into renewables. The article addresses the question of sustainability of energy generated from PVs through an environmental assessment of a building-integrated PV system (BIPV) connected to the grid through net metering. Employing retrospective life cycle analysis (LCA), with the CCaLC2 software and ecoinvent data, the article shows that the carrying structure and other balance of system (BOS) components are responsible for a three times higher energy payback time than the literature average. However, total environmental impact can be lowered through reuse or reinstallation of PVs on the same building structure after the 30-year interval. Further ways to improve environmental efficiency include identifying the most polluting materials for each LCA parameter. The results of this study are of interest to researchers and producers of PVs and organizations investing and promoting decentralized power production through PVs.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2019.05a
• /
• pp.59-60
• /
• 2019

Thermal bridge on a building envelope causes additional heat loss which increases the heating energy consumption. As the higher building insulation performance is required, heat loss through thermal bridge becomes higher proportion among total building heating energy consumption. For the exterior insulation and finish system, thermal bridge between window frame and concrete wall should be constidered as one of main reasons of heat loss. In this study, the thermal bridge barrier between window frame and concrete wall(STAR) was proposed as the best practice for reducing thermal bridge. The STAR was confirmed that the use of thermal bridge barrier imporved the annual heat energy capacity by 35% or more and the innitial construction cost by 7.4% or less because of additional interior insulation against condensation. Finally the life cycle cost during 20 year by heating energy of a building reduced by 25% or more compared with the exist technology. This STAR thermal bridge barrier will be used as the main technology to improve the energy efficiency of building.

• New & Renewable Energy
• /
• v.3 no.2 s.10
• /
• pp.31-39
• /
• 2007

화석연료의 사용으로 인한 자원고갈과 지구온난화 영향 그리고 에너지 안보문제의 해결을 위해 세계 각국들은 대체에너지 개발에 많은 노력을 기울이고 있다. 그 중 수소는 다양한 경로를 통해 생산 가능하고, 수송연료로 사용 시, 유해 물질이 거의 배출되지 않는다는 장점 때문에 가장 주목받는 대체 에너지원이다. 현재는 수소생산 기술개발을 통해 상업화시기를 앞당기려고 하는 수소에너지 시대의 진입시점이라 할 수 있다. 그러나 수소는 생산경로에 따라 다양한 환경성 및 경제성 결과를 도출 할 수 있기 때문에 다양한 평가가 요구된다. 본 연구에서는 국내 수소생산 방식으로 개발/상용화되어있는 Natural Gas Steam Reforming (NGSR), Naphtha Steam Reforming (Naphtha SR), Water Electrolysis (WE)에 대하여, Life Cycle Assessment (LCA)와 Life Cycle Costing Analysis (LCCA) 방법을 사용하여, 수소경로 전반에 대한 즉, 원료채취부터 자동차로 주행하였을 때까지의 각 대상 수소경로의 환경성과 경제성을 평가하였다. LCA와 LCCA 결과는 Naphtha SR과 NGSR 수소경로에서 지구온난화와 화석자원 소모 부문 모두 기존연료 (가솔린, 디젤)와 비교해서 개선효과가 뚜렷하게 나타났으나, WE 수소경로는 오히려 환경부하가 증가되는 것으로 나타났다. 또한 경제성 측면에서는, 수소 판매 시 가솔린과 동일한 연료세율을 부과하더라도 수소가 가솔린에 비해 가격경쟁력을 확보하게 되는데, 이는 주행 시 수소자동차의 연비가 기존 차량에 비해 월등히 좋기 때문에 연료비용의 이점 때문이다. 만약, 수소에 연료세를 부과하지 않는 다면, Naphtha SR로 생산하여 유통한 수소가 수송연료로서 가장 뛰어난 비용효율성을 갖는 것으로 나타났다.

• Journal of Energy Engineering
• /
• v.24 no.2
• /
• pp.45-50
• /
• 2015

In Korea ranking sixth out of The world's greenhouse gas emissions, all Korean public buildings have to implement obligatorily renewable energy systems for energy production to reduce the greenhouse gas emissions from the energy consumed in operation, maintenance and management of buildings. The optimum combination and application rates for each energy source emerge from analyzing the trend of previous studies and the energy consumption is simulated by using a dynamic energy simulation program and the initial investment costs, the energy costs, the maintenance costs, the replacement costs emerge based on the calculated result. The result show that the total life cycle cost of 100% gerthermal is the lowest with \ 2,105,974,344 on the analysis results.