Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Energy Engineering
Journal Basic Information
Journal DOI :
The Korea Society for Energy Engineering
Editor in Chief :
Volume & Issues
Volume 24, Issue 4 - Dec 2015
Volume 24, Issue 3 - Sep 2015
Volume 24, Issue 2 - Jun 2015
Volume 24, Issue 1 - Mar 2015
Selecting the target year
A Study on Proper Location of Welding Defect in Three Point Bend Testing with MDPE Pipe
Lai, Huan Sheng ; Yoon, Kee Bong ; Kil, Seong Hee ;
Journal of Energy Engineering, volume 24, issue 1, 2015, Pages 1~9
DOI : 10.5855/ENERGY.2015.24.1.001
Welding defects affect the performance of welded pipe joints. In this study, a three point bend test of welded steel and medium density polyethylene (MDPE) pipe joints with defects of various defect locations and defect materials was studied using the finite element method. The defect was assumed to be located at 12 o'clock, 3 o'clock or 6 o'clock direction. The results showed that pipes failed more easily on the compression side due to stress or local buckling. The air defect was more dangerous than the steel defect if the defect was located in the compression side; otherwise, the defect material effect on the integrity of pipes was ignorable. It is argued that the integrity of pipes with defects in the compression side is weaker than that in other regions, and the defect should be located in the compression side or the 12 o'clock position in the three point bend test to maximize the effect of defect existence on the pipe structural integrity.
Development and Application of RCM Process for the Optimized Maintenance of Railway Vehicle
Shin, Kun Young ; Lee, Hi Sung ;
Journal of Energy Engineering, volume 24, issue 1, 2015, Pages 10~16
DOI : 10.5855/ENERGY.2015.24.1.010
Recently, RCM(reliability centered maintenance) process is introduced and applied for the planning and implementing efficient and effective maintenance system in terms of optimal rolling stock maintenance. Particularly, cost-time benefits analysis associated with the implementation of RCM for rolling stock maintenance is necessary and required for railway operator in advance. The RCM process was primarily starting from military, airplane and nuclear industries and is now adapted in railway industry for local railway operators. This paper focuses on suggesting the way of connecting the RCM process with railway maintenance activities in the railway operation field. Thus, in order to introduce and establish reliability activities, it needs to review and evaluate the maintenance environment in the organizational point of view. Based on these reviews and evaluations, various maintenance methodologies are reviewed for customizing local railway field situations and establish specific process in the application of major systems on the reliability technology. In this paper, the railway RCM process is proposed for the establishment and construction of the systematic and optimal maintenance system.
Reliability Improvement Method of the Electrical Door System for the Railway Vehicles
Yang, Yong Joon ; Lee, Hi Sung ;
Journal of Energy Engineering, volume 24, issue 1, 2015, Pages 17~23
DOI : 10.5855/ENERGY.2015.24.1.017
Electrical door system is one of the most essential items for the successful commercial operation of the railway vehicles. Nowadays, reliability values of electrical door system have a tendency to be included in technical requirements for design and manufacturing of rolling stocks. Manufacturer shall meet the reliability target values of electrical door system which is proposed by railway operator in procurement contract book. Railway operator shall approve the supplier's the reliability target values based on maintenance operation data. Railway operators are in the transition stage from the framework of maintenance interval based on time to the framework of maintenance interval based on distance. In this study, failure rates of the electrical door system currently used in railway vehicles are collected from maintenance field data. Failure rates are analyzed by using Minitab. Several kinds of plan for improving reliability are also suggested. It is necessary to keep studying on reliability prediction methodology, applying it in the field and implementing on improvement of reliability through feedback as well. Further, it will be useful for determining new maintenance policies or changing maintenance intervals for existing railway vehicles.
A Study on the Thermal Comfort Zone and Energy Use of Radiant Floor Heating by Residential Style and Clothing Level
Kim, Sang-Hun ; Chung, Kwang-Seop ; Kim, Young-Il ;
Journal of Energy Engineering, volume 24, issue 1, 2015, Pages 24~31
DOI : 10.5855/ENERGY.2015.24.1.024
The purpose of this study is to provide the thermal comfort range according to the residential style and clothing level at radiant floor heating space, and compare the annual energy consumption and energy cost for each condition. Lower neutral point temperature has been stood for floor sitting style than chair sitting style, which appears that the thermal sensation was affected by local heat transfer between floor surface and the human body. The result of research indicates that neutral point temperature was in inverse proportion with the clothing level. It is interpreted that the increasing of clothing level results decrement of heat loss from human body, and is available to achieve same thermal comfort at lower room temperature. It was analyzed that the floor sitting style is more economical residential style than the chair sitting style, because the energy consumption of the floor sitting style is saved by 6.0% in average to compare with that of the chair sitting style. It is analyzed that energy consumption has been decreased by 13.5% with the clothing level of 1.2 Clo than with that of 1.0 Clo, and decreased by 18.0% than with that of 0.8 Clo, which explains that the energy saving can be achieved with the variation in life habit to increase the clothing level.
Economic Feasibility Analysis of the Metropolitan Area Green Heat Project
Kim, Sang-Kee ; Kim, Lae Hyun ; Yoo, Seung-Hoon ;
Journal of Energy Engineering, volume 24, issue 1, 2015, Pages 32~41
DOI : 10.5855/ENERGY.2015.24.1.032
The Metropolitan Area Green Heat Project (MAGHP), which collects unused heat gathered from power plants, steel works, landfills in western Metropolitan area and distribute it to integrated energy business (IEB) companies, is proposed for the purpose of enhancing energy efficiency and providing low-price heat for IEB companies. Therefore, in order to decide on whether to initiate the MAGHP, the economic feasibility analysis of the project is widely demanded. This paper attempts to consider and measure four economic benefits: heat supply benefit, production cost reduction benefit, greenhouse gas mitigation benefit, and air quality improvement benefit. In addition, the paper tries to conduct the economic feasibility analysis. The project requires three-year investment and thirty-year operation. Three important findings emerge from the analysis. First, its net present value is computed to be 1,269 billion won and more than zero. Second, its benefit/cost ratio is calculated to be 1.72 and bigger than 1.0. Third, its internal rate of return is estimated to be 24.26% and larger than the social rate of return, 5.5%. In conclusion, the MAGHP is socially profitable and should be conducted immediately.
Experimental Investigation of Steam Condensation Heat Transfer in the Presence of Noncondensable Gas on a Vertical Tube
Lee, Yeon-Gun ; Jang, Yeong-Jun ; Choi, Dong-Jae ; Kim, Sin ;
Journal of Energy Engineering, volume 24, issue 1, 2015, Pages 42~50
DOI : 10.5855/ENERGY.2015.24.1.042
To evaluate the heat removal capability of a condenser tube in the PCCS of an advanced nuclear power plant, a steam condensation experiment in the presence of noncondensable gas on a vertical tube is performed. The average heat transfer coefficient is measured on a vertical tube of 40 mm in O.D. and 1.0 m in length. The experiments covers the pressures of 2-4 bar, and the mass fraction of air ranges from 0.1 up to 0.7. From the experimental results, the effects of the total pressure and the concentration of air on the condensation heat transfer coefficient are investigated. The measured data are compared with the predictions by Uchida's and Tagami's correlations, and it is revealed that these models underestimate the condensation heat transfer coefficient of the steam-air mixture.
Numerical Analysis and Demonstration Test on the Performance of a Static Mixer for mixing Biogas and Town Gas for the 5MW Biogas Turbine
Cha, Hyoseok ; Song, Soonho ; Park, Jong Yeon ; Kim, Young Il ; Mun, Sung Young ;
Journal of Energy Engineering, volume 24, issue 1, 2015, Pages 51~57
DOI : 10.5855/ENERGY.2015.24.1.051
The purpose of this study is to verify the performance of a static mixer for mixing of biogas and town gas by numerical analysis and demonstration test. The reason for designing a static mixer is that there is a need to mix town gas with biogas when there is less production of biogas in biogas sites. Non-uniformity in the outlet section was calculated for investigating the performance of a static mixer. Non-uniformity was based on the mole fraction of methane in a mixture of biogas and town gas. Low non-uniformity means that biogas and town gas are mixed well through this static mixer. Also, pressure drop at the outlet section of a static mixer was calculated. The pressure drop is less than 0.2% in this static mixer. This static mixer is suitable for applying to a 5MW bio-gas turbine through the demonstration test in the field.
Marginal Abatement Cost Analysis for the Korean Residential Sector Using Bottom-Up Modeling
Chung, Yongjoo ; Kim, Hugon ; Paik, Chunhyun ; Kim, Young Jin ;
Journal of Energy Engineering, volume 24, issue 1, 2015, Pages 58~68
DOI : 10.5855/ENERGY.2015.24.1.058
A marginal abatement cost analysis has been conducted to analyze the effects of abatement measures on greenhouse gas (GHG) emissions for the Korean residential sector. A bottom-up model using MESSAGE has been developed by defining the energy demand and constructing the reference energy system for the residential sector. A great amount of activity data has also been analyzed. Abatement potentials and related costs of individual abatement measures are investigated. The result from the marginal abatement cost analysis may provide general guidelines and procedures for the establishment of GHG abatement polices.
A Study on the Application of Simulation-based Simplified PMV Regression Model for Indoor Thermal Comfort Control
Kim, Sang-Hun ; Yun, Sung-Jun ; Chung, Kwang-Seop ;
Journal of Energy Engineering, volume 24, issue 1, 2015, Pages 69~77
DOI : 10.5855/ENERGY.2015.24.1.069
The PMV regression analysis was conducted for this model based on a database of the PMV variables. PMV regression model simplification was completed through sensitivity and data analysis. The simplified PMV regression model's and Fanger PMV model was confirmed through MAE and RMSE. And the EMS in EnergyPlus was used to establish a simplified PMV regression analysis-based thermal comfort control. Also, the thermal comfort controls based on simplified PMV model and the Fanger PMV model were applied to the building model, it was confirmed that both controls met the thermal comfort range in more than 90% of cases during the air conditioning period.
Focusing effect of a Metallic Layer according to the Cooling Condition and Height in a Severe Accident
Moon, Je-Young ; Chung, Bum-Jin ;
Journal of Energy Engineering, volume 24, issue 1, 2015, Pages 78~87
DOI : 10.5855/ENERGY.2015.24.1.078
Focusing effect of a metallic layer in a severe accident depending on the aspect ratios and cooling conditions of top plate and side wall was investigated. Experiments were carried out for Rayleigh numbers and aspect ratio in the range of
, 0.135~0.541 respectively. In order to achieve high Rayleigh numbers, the heat transfer experiments were replaced by mass transfer experiments based on the heat and mass transfer analogy. A sulfuric acid-copper sulfate (
) electroplating system was adopted as the mass transfer system. The experimental results agreed well with the Rayleigh-Benard natural convection correlations of Dropkin and Somerscales and Globe and Dropkin. When compared with the standard Rayleigh-Benard problem, the cooling by the side wall is even higher than the top. For a shorter height, the interaction between the heated and cooled plumes increases due to decrease of the height. Thus, the heat transfer increases.
Flow Analysis for Optimal Design of Small Gear Pump
Lee, Suk-Young ; Kim, Seung-Chul ;
Journal of Energy Engineering, volume 24, issue 1, 2015, Pages 88~96
DOI : 10.5855/ENERGY.2015.24.1.088
Gear pump has a simple structure high reliability, easy operation and maintenance, widely used as a source of hydraulic system of hydraulic. In general, the gear pump was designed using variety of variables, the variables through the analysis of the mass flow rate and efficiency. In this paper, three-dimensional flow of the gear pump, in order to produce the optimal design of product, analysis was performed by using commercial software ANSYS v15.0 CFX. And then, combination of design parameters selected by ANSYS was carried out to confirm the simulation result. The efficiency and mass flow rate of the gear pump were studied by varying its rotational speed and the clearance between the gear tip and the housing. In the simulation results, as the rotational speed were increased, the average mass flow rate and efficiency increased. Furthermore, as the clearance between the gear tip and the housing was increased, the average mass flow rate and efficiency decreased.
Influence of the Geometry on the Natural Convection Heat Transfer inside a Vertical Cylinder
Ohk, Seung-Min ; Chung, Bum-Jin ;
Journal of Energy Engineering, volume 24, issue 1, 2015, Pages 97~103
DOI : 10.5855/ENERGY.2015.24.1.097
Natural convection heat transfer rates in vertical pipes were measured varying the diameter, length, and roughness of vertical cylinder. To achieve high Rayleigh number with relatively small test rig, mass transfer experiments instead of heat transfer were performed based on the analogy. Prandtl number was 2,014. The length of vertical cylinder was 0.1m, 0.3m, and 0.5m, which correspond to GrL
. To each length of vertical cylinder, the heat transfer rates were measured varying the iameter 0.005m, 0.01m, and 0.03m. The heat transfer rate for a short length pipe(0.1m) agreed with the prediction from Le Fevre correlation developed for a vertical plate for all diameter. The heat transfer rate decreases as the diameter and the length of the pipe increases. The heat transfer rate inside of vertical cylinder is affected by roughness only for a laminar flow regime.
Using the Demand-driven Model-based Inter-industry Analysis to Examine the Economic Effects of Petroleum Refinery Sector
Kim, Ho-Young ; Song, Tae-Ho ; Yoo, Seung-Hoon ;
Journal of Energy Engineering, volume 24, issue 1, 2015, Pages 104~113
DOI : 10.5855/ENERGY.2015.24.1.104
This study tried to conduct a comparative analysis on the yearly economic effects of petroleum products sector. Inter-industry tables published 1990~2012 are used in this study. Especially petroleum products sector is specified as exogenous to identify the economic effects on own and other sectors. Production-inducing effect, value-added creation effect, and employment-inducing effect are quantified based on demand-driven model. The results of the analysis, the case of annual production inducing-effect, show the downward trend from 1993 to 2008. and It seemed to be constant from 2009 to 2012. The value-added inducing-effect, from 1990 to 1998, shows a rising trend. the since 1998, it was found to decline steadily. Employment-inducing effect is shown a steadily decreasing trend from 1990 to 2008, and has been kept constant from 2010 at the level under 1.300(person/one billion won). These results of in comparison with the past are significant in that it can be objectively evaluate the domestic oil industry at the present time. and it can be usefully utilized to predict the economic effect of future oil industry.
Experimental Investigation on the Droplet Entrainment in the Air-Water Horizontal Stratified Flow
Bae, Byeong Geon ; Yun, Byong Jo ; Kim, Kyoung Doo ; Bae, Byoung Uhn ;
Journal of Energy Engineering, volume 24, issue 1, 2015, Pages 114~122
DOI : 10.5855/ENERGY.2015.24.1.114
In the high convective gas flow condition, irregular shaped water waves from which droplet entrainment occurs are generated under horizontally stratified two-phase flow condition. KAERI proposed a new mechanistic droplet entrainment model based on the momentum balance equation consisting of the shear stress, surface tension, and gravity forces. However, this model requires correlation or experimental data of several physical parameters related to the wave characteristics. In the present study, we tried to measure the physical parameters such as wave slope, wave hypotenuse length, wave velocity, wave frequency, and wavelength experimentally. For this, an experiment was conducted in the horizontal rectangular channel of which width, height, and length are, respectively, 40 mm, 50 mm, and 4.2 m. In the present test, the working fluids are chosen as air and water. The PIV technique was applied not only to obtain images for phase interface waves but also to measure the velocity field of the water flow. Additionally, we developed the parallel wire conductance probe for the confirmation of wave height from PIV image. Finally, we measured the physical parameters to be used in the validation of new droplet entrainment model.
A Study on Quantitative methodology to Assess Cyber Security Risks of EMS
Woo, Pil Sung ; Kim, Balho H. ;
Journal of Energy Engineering, volume 24, issue 1, 2015, Pages 123~131
DOI : 10.5855/ENERGY.2015.24.1.123
This paper aims to identify and clarify the cyber security risks and their interaction with the power system in Smart Grid. The EMS and other communication networks interact with the power system on a real time basis, so it is important to understand the interaction between two layers to protect the power system from potential cyber threats. In this study, the optimal power flow(OPF) and Power Flow Tracing are used to assess the interaction between the EMS and the power system. Through OPF and Power Flow Tracing based analysis, the physical and economic impacts from potential cyber threats are assessed, and thereby the quantitative risks are measured in a monetary unit.
A Study on Spray and Combustion Characteristics of Biodiesel Blended Diesel Fuel in a Constant Volume Combustion Chamber
Suh, Hyun-Uk ; Jeon, Chung-Hwan ;
Journal of Energy Engineering, volume 24, issue 1, 2015, Pages 132~136
DOI : 10.5855/ENERGY.2015.24.1.132
The objective of this study is to investigate the effect of biodiesel blending on spray and combustion characteristics. In order to this, blended fuels containing 0, 5, 20, 50, 100% biodiesel in weight fraction was injected via common rail to constant volume combustion chamber. As a result, spray cone angle decreased and the Sauter mean diameter increased because of the higher dynamic viscosity and density of biodiesel, however, it does not seemed that spray penetration was affected by these factors considerably. In the combustion experiment, ignition delay of biodiesel was shorter than that of diesel due to higher cetane number. And the peak value of heat release rate increased and the end of combustion was advanced owing to higher combustion efficiency cause by the characteristic of oxygenated fuel.
LMDI Decomposition Analysis for Electricity Consumption in Korean Manufacturing
Han, Joon ;
Journal of Energy Engineering, volume 24, issue 1, 2015, Pages 137~148
DOI : 10.5855/ENERGY.2015.24.1.137
So far, the phenomenon of "electrification" has been deepened in Korean industry and especially direct heating energy which accounted for 44.0%(2010) of total energy consumed in Korean manufacturing has been significantly electrified. This paper decomposed electricity consumption for direct heating in Korean manufacturing from 1992 to 2012 using LMDI(Log Mean Divisia Index). This paper includes 4 different factors such as electricity proportion effect, direct heating proportion effect, energy intensity effect and added value effect. And this paper compared the consumption pattern by business type. As results, electricity proportion effect had contributed the most to the increase of electricity consumption for direct heating in Korean manufacturing. And Petrol-Chemical and Iron & Steel had the most electrification of direct heating.
Numerical study on the thermal-hydraulic safety of the fuel assembly in the Mast assembly
Kim, YoungSoo ; Yun, ByongJo ; Kim, HuiYung ; Jeon, JaeYeong ;
Journal of Energy Engineering, volume 24, issue 1, 2015, Pages 149~163
DOI : 10.5855/ENERGY.2015.24.1.149
In this study, we conducted study on the confirmation of thermal-hydraulic safety for Mast assembly with Computational Fluid Dynamics(CFD) analysis. Before performing the natural convection analysis for the Mast assembly by using CFD code, we validated the CFD code against two benchmark natural convection data for the evaluation of turbulence models and confirmation of its applicability to the natural convection flow. From the first benchmark test which was performed by Betts et al. in the simple rectangular channel, we selected standard k-omega turbulence model for natural convection. And then, calculation performance of CFD code was also investigated in the sub-channel of rod bundle by comparing with PNL(Pacific Northwest Laboratory) experimental data and prediction results by MATRA and Fluent 12.0 which were performed by Kwon et al.. Finally, we performed main natural convection analysis for fuel assembly inside the Mast assembly by using validated turbulence model. From the calculation, we observed stable natural circulation flow between the mast assembly and pool side and evaluated the thermal-hydraulic safety by calculating the departure from nucleate boiling ratio.
Public Preferences for Replacing Hydro-Electricity Generation with Coal-Fired Power Generation
Choi, Hyo-Yeon ; Ryu, Mun-Hyun ; Yoo, Seung-Hoon ;
Journal of Energy Engineering, volume 24, issue 1, 2015, Pages 164~171
DOI : 10.5855/ENERGY.2015.24.1.164
Although coal-fired power generation has played a role as base load unit, it has incurred various social costs in the process of generating and providing electricity. It is necessary to extend the proportion of low-carbon power generations, and reduce the ratio of coal-fired power generation to cope with global climate changes. This study, therefore, attempts to estimate the public's willingness-to-pay (WTP) for substitution of supplied electricity from hydro-electricity generation, a representative renewable energy, for coal-fired power generation. To this end, we apply the contingent valuation (CV) method, widely used technique when valuing non-market goods, to elicit the public's WTP. In addition, a spike model is employed to consider zero WTPs. After the empirical analysis with 1,000 households CV survey data, the results show that mean household's WTP for replacing supplied electricity from hydro-electricity generation with coal-fired power generation is estimated to be about 54 KRW per kWh. The results of this study are expected to contribute to determining energy-mix and provide benefit information of hydro-electricity generation.