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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Energy Engineering
Journal Basic Information
Journal DOI :
The Korea Society for Energy Engineering
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Volume & Issues
Volume 23, Issue 4 - Dec 2014
Volume 23, Issue 3 - Sep 2014
Volume 23, Issue 2 - Jun 2014
Volume 23, Issue 1 - Mar 2014
Selecting the target year
The Study of the 160Ah Ni-MH battery for Diesel Engine Starting
Park, Dong Pil ; Kim, Lae Hyun ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 1~8
DOI : 10.5855/ENERGY.2014.23.4.001
For this study, a 160Ah Ni-MH battery is produced with parallel arranged two 80Ah Ni-MH batteries as an unit, in order to start diesel generator(engine) in place of Lead Acid battery or Ni-cd battery which contain indicated toxic pollutant of Environmental pollution, by high capacity Ni-MH battery. And the ternary electrolyte recipe is requested to develop proper electrodes of the 160Ah Ni-MH battery, and then the 160Ah battery can be tested at high rate discharging performance. Zn is added to negative electrode for the improvement of performance. 160Ah Ni-MH battery has been tested in various experiments for diesel engine starting. As the result, diesel engine starting is found successfully.
The Study on the improvement of vehicle fuel economy test method according to the characteristics of test fuel
Lee, Minho ; Kim, Jeonghwan ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 9~18
DOI : 10.5855/ENERGY.2014.23.4.009
These test methods, the current domestic vehicles fuel economy calculation method is tested on a dynamometer for vehicles after you have installed the vehicle, given the test mode(FTP-75 & HWFET mode, etc.) are measured by vehicle emissions and fuel economy by seeking to have the results approach, the carbon balance method. At this point, using the carbon balance method is a test method was developed seeking fuel for a standard fuel properties, where the value of the constant and saved test was measured in THC, CO,
has a value calculation. Therefore, use fuel which is changed every time you test the fuel properties characteristics are not considered exactly. In this study, using the carbon balance method and fluid flow rate of the fuel used in the actual test is measured by comparing the results with the flow measurement methods, properties of the fuel used for the test attribute to study ways that can be considered, taking into account the physical attributes of a more diverse fuel line and fuel economy improved measurement methods that can be reviewed.
Safety Characteristics of Metal-Fueled Sodium-Cooled Fast Reactor
Jeong, Hae-Yong ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 19~30
DOI : 10.5855/ENERGY.2014.23.4.019
The leading countries in nuclear technology development are concentrating their efforts on the development of Sodium-cooled Fast Reactor, which is one of the Generation-IV nuclear reactor systems characterized by a sustainability, an enhanced safety, proliferation resistance, and improved economics. Especially, the Republic of Korea is developing a Sodium-cooled Fast Reactor equipped with metallic-fuel. This type of fast reactor has superior inherent safety and passive safety characteristics. Further, sodium-cooled fast reactors enable the reuse of spent fuel and the closing of fuel cycle, thus, it increases the sustainability of nuclear energy. Many countries are planning the deployment of sodium-cooled fast reactors before 2050 in their energy mix.
The Economic Effects of the New and Renewable Energies Sector
Lim, Seul-Ye ; Park, So-Yeon ; Yoo, Seung-Hoon ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 31~40
DOI : 10.5855/ENERGY.2014.23.4.031
The Korean government made the 2nd Energy Basic Plan to achieve 11% of new and renewable energies distribution rate until 2035 as a response to cope with international discussion about greenhouse gas emission reduction. Renewable energies include solar thermal, photovoltaic, bioenergy, wind power, small hydropower, geothermal energy, ocean energy, and waste energy. New energies contain fuel cells, coal gasification and liquefaction, and hydrogen. As public and private investment to enhance the distribution of new and renewable energies, it is necessary to clarify the economic effects of the new and renewable energies sector. To the end, this study attempts to apply an input-output analysis and analyze the economic effects of new and renewable energies sector using 2012 input-output table. Three topics are dealt with. First, production-inducing effect, value-added creation effect, and employment-inducing effect are quantified based on demand-driven model. Second, supply shortage effects are analyzed employing supply-driven model. Lastly, price pervasive effects are investigated applying Leontief price model. The results of this analysis are as follows. First, one won of production or investment in new and renewable energies sector induces 2.1776 won of production and 0.7080 won of value-added. Moreover, the employment-inducing effect of one billion won of production or investment in new and renewable energies sector is estimated to be 9.0337 persons. Second, production shortage cost from one won of supply failure in new and renewable energies sector is calculated to be 1.6314 won, which is not small. Third, the impact of the 10% increase in new and renewable energies rate on the general price level is computed to be 0.0123%, which is small. This information can be utilized in forecasting the economic effects of new and renewable energies sector.
A study of a combined release model using perturbation solutions
Kim, Myungbae ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 41~48
DOI : 10.5855/ENERGY.2014.23.4.041
Leak of liquid has been categorized conventionally into instantaneous release and continuous release. In this study, the spread of cryogenic liquid due to limited period of release is investigated for the first time to establish a new classification method with recognizing the irrationality of the conventional one. Such physical phenomena are governed by simultaneous equations concerning volume, radius and height of pool of the cryogenic liquid, and major parameters are evaporation rate per unit area, time of release, and spill quantity. The simultaneous governing equations is decoupled to get efficiently perturbation solutions. As the results, for the same spill quantity, in view of release model, combined release model that consists of continuous and consecutive instantaneous model is necessary with small time of release, while continuous model is solely required with large time of release. Also, the combined model is necessary for small spill quantity with the same time of release. These two regimes of release are clearly distinguished using the perturbation solution to provide a clear basis for the new classification of release models.
Empirical Study on water wall tube corrosion mechanism for Tangential type coal fired power plant boiler
Baek, Sehyun ; Kim, HyunHee ; Park, Hoyoung ; Ko, SungHo ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 49~55
DOI : 10.5855/ENERGY.2014.23.4.049
In this study, boiler tube thickness measurement and numerical analysis were conducted for standard 500MW coal-fired power plant in order to research the mechanism of tangential-fired boiler corrosion empirically. The most dominant corrosion mechanism of tangential-fired boiler waterwall was corrosion by sulfur contained in the unburned carbon. And the secondary mechanism was
gas corrosion at localized reducing atmosphere. It is required to decrease the air-stage combustion operation in order to mitigate the waterwall tube corrosion. Also stringent coal pulverization quality control and reinforcing work for corrosion susceptible area such as anti-corrosion coatings is required
An Experimental Study on the Optical Separation of Highly Concentrated Sunlight
Kim, Yeongmin ; Mo, Yonghyun ; Shin, Sangwoong ; Oh, Seungjin ; Chun, Wongee ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 56~60
DOI : 10.5855/ENERGY.2014.23.4.056
Highly concentrated sunlight obtained from a solar concentrator mounted on a solar tracker can be divided into the infrared and visible region before it is actually applied. That is, solar rays are directed toward a unit optically separating sunlight into the infrared and visible region by a hot mirror as they impinge on the surface of a secondary reflector. The Infrared rays can be utilized for thermoacoustic applications while visible rays can be utilized for indoor lighting. This work introduces the separation of two different kinds of light; sunlight and artificial light. As for the artificial light, its wavelength extended from 400m to 720m for the visible region and 620m to 940m for the infrared region. Comparatively, a series of tests performed on sunlight revealed its separation in the visible region from 460m to 680m whereas from 620m to 940m for the artificial light.
Effect of economic growth, industrial structure, efficiency improvement, decarbonization of power sector and fuel substitution for the transition to low carbon society by 2050
Park, Nyun-Bae ; Hong, Sungjun ; Park, Sang Yong ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 61~72
DOI : 10.5855/ENERGY.2014.23.4.061
This paper analyzed transition pathways toward a low carbon society in Korea to meet global
climate target. Lower economic growth, industrial structure change, enhance of energy demand management, decarbonization of power sector, and replacement of low carbon fuel could reduce greenhouse gas (GHG) emission from fuel combustion in 2050 by 67% against in 2011, or by 74% against in BAU (Business-As-Usual). Lower economic growth contributes to 13% of cumulative emission reduction relative to BAU, industrial structure change 9%, enhance of energy demand management 72%, decarbonization of power sector 5% and replacement of low carbon fuel 1% respectively. Final energy consumption in 2050 needs to be reduced to 50% relative to 2011, or to 41% relative to BAU. Nuclear, coal and renewable energy represent 31%, 40%, 2% respectively among electricity generation in 2011, but 38%, 2%, 32% in 2050. CCS represents 23% of total generation in 2050. Emission intensity of electricity in 2050 was decreased to 19% relative to 2011, or to 24% relative to BAU. Primary energy in 2050 was decreased to 64% compared to 2011, or to 44% compared to BAU. Final energy consumption, primary energy supply and GHG emission from fuel combustion from 1990 to 2011 increased by 176%, 197%, 146%. Radical change from historical trend is required to transit toward a low carbon society by 2050. Appropriate economic growth, structural change to non-energy intensive industries, energy technology research, development and deployment (RD&D) in terms of enhancement of energy efficiency and low carbon energy supply technologies, and fuel change to electricity and renewable energy are key instruments.
An Overall Investigation of Break Simulators for LOCA Scenarios in Integral Effect Tests
Kim, Yeon-Sik ; Park, Hyun-Sik ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 73~88
DOI : 10.5855/ENERGY.2014.23.4.073
Various studies on the critical flow models for sub-cooled and/or saturated water were reviewed, especially on Fauske, Moody, and Henry for basic theoretical models; Zaloudek for insight into physical phenomena for a critical flow in an orifice type flow path; Sozzi & Sutherland for a critical flow test of saturated and sub-cooled water at high pressure for orifice and nozzles; and a Marviken test on a full-scale critical flow test. In addition, critical flow tests of sub-cooled water for the break simulators in integral effect test (IET) facilities were also investigated, and a hybrid concept using Moody's and Fauske's models was considered by the authors. In the comparison of the models for the selected test data, discussions of the effect of the diameters, predictions of the critical flow models, and design aspects of break simulator for SBLOCA scenarios in the IET facilities were presented. In the effect of diameter on the critical flow rate with respect to all dimensional scales, it was concluded that the effect of diameter was found irrespective of diameter sizes. In addition, the diameter effect on slip ratio affecting the critical flow rate was suggested. From a comparison of the critical flow models and selected test data, the Henry-Fauske model of the MARS-KS code was found to be the best model predicting the critical flow rate for the selected test data under study.
The Study on the Long-term Reliability Characteristics of Ribbon Joint: Solar Cell Ribbon Thickness and Solder Compositions
Jeon, Yu-Jae ; Kang, Min-Soo ; So, Kyung-Jun ; Lee, Jae-June ; Shin, Young-Eui ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 88~94
DOI : 10.5855/ENERGY.2014.23.4.088
In this paper, Thermal Shock tests were performed varying the composition of the solder and ribbon thickness (A-type:0.2mm/60Sn40Pb, B-type:0.25mm/60Sn40Pb, C-type:0.2 /62Sn36Ag2Pb, D-type:0.25mm/62Sn36Ag2Pb) for evaluating the long-term reliability about Ribbon junction of Silicon solar cells. Thermal Shock test condition was performed during the 600cycles having
temperature range each 15 minutes; One cycle time was 30min. As a result, the initial efficiency of the A-type, B-type, and C, D-type were showed 15.0%, 15.4% and 15.8% respectively. After thermal shock test, the efficiency decreasing-rate of each type were as follow that A-type was 13.8%, B-Type was 15.4%. C-Type and D-Type was 15.3% and 16.2%, respectively. Also, degradation of surface changes and I-V characteristic curves were showed that the series resistance of the A, C-type was increased. Also, current lowering starting point of C-type shown 0.05volt[v] earlier than that of A-type. And B, D-type shown characteristics of composite lowering efficiency such as increase of series resistance, decrease of parallel resistance and cell damage. Therefore Initial solderability and efficiency of specimens using the solder with SnAgPb were superior. But, It has inferior the long-term reliability. The test was confirmed that as the ribbon thickness increases, long-term reliability of solar cell will decrease.
Preliminary Thermal-Hydraulic Analysis of the CANDU Reactor Moderator Tank using the CUPID Code
Choi, Su Ryong ; Lee, Jae Ryong ; Kim, Hyoung Tae ; Yoon, Han Young ; Jeong, Jae Jun ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 95~105
DOI : 10.5855/ENERGY.2014.23.4.095
The CUPID code has been developed for a transient, three-dimensional, two-phase flow analysis at a component scale. It has been validated against a wide range of two-phase flow experiments. Especially, to assess its applicability to single- and two-phase flow analyses in the Calandria vessel of a CANDU nuclear reactor, it was validated using the experimental data of the 1/4-scaled facility of a Calandria vessel at the STERN laboratory. In this study, a preliminary thermal-hydraulic analysis of the CANDU reactor moderator tank using the CUPID code is carried out, which is based on the results of the previous studies. The complicated internal structure of the Calandria vessel and the inlet nozzle was modeled in a simplified manner by using a porous media approach. One of the most important factors in the analysis was found to be the modeling of the tank inlet nozzle. A calculation with a simple inlet nozzle modeling resulted in thermal stratification by buoyance, leading to a boiling from the top of the Calandria tank. This is not realistic at all and may occur due to the lack of inlet flow momentum. To improve this, a new nozzle modeling was used, which can preserve both mass flow and momentum flow at the inlet nozzle. This resulted in a realistic temperature distribution in the tank. In conclusion, it was shown that the CUPID code is applicable to thermal-hydraulic analysis of the CANDU reactor moderator tank using the cost-effective porous media approach and that the inlet nozzle modeling is very important for the flow analysis in the tank.
A Study on the Estimation of REC Multiplier for ESS Introduction
Kim, Kang-Won ; Kim, Balho H. ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 106~111
DOI : 10.5855/ENERGY.2014.23.4.106
In order to manage the gradual increase of electricity demand, the United States, Japan, and Europe are seeking to achieve overall change of electric power system by introducing solutions such as smart grid. Among these solutions, there are various research projects regarding the Electricity Storage System (ESS), which aims to promote the efficient usage of electricity and grid system of new and renewable energy system. Korean government revised the law by including ESS in new and renewable energy facilities to accelerate ESS deployment. Following the same direction of the government policy, this study suggests methodologies of setting REC weighted value that guarantees investment financial feasibility when new and renewable power producers install ESS.
The MARS Simulation of the ATLAS Main Steam Line Break Experiment
Ha, Tae Wook ; Yun, Byong Jo ; Jeong, Jae Jun ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 112~122
DOI : 10.5855/ENERGY.2014.23.4.112
A main steam line break (MSLB) test at the ATLAS facility was simulated using the best-estimate thermal-hydraulic system code, MARS-KS. This has been performed as an activity at the third domestic standard problem for code benchmark (DSP-03) that has been organized by Korea Atomic Energy Research Institute (KAERI). The results of the MSLB experiment and the MARS input data prepared for the previous DSP-02 using the ATLAS facility were provided to participants. The preliminary MSLB simulation using the base input data, however, showed unphysical results in the primary-to-secondary heat transfer. To resolve the problems, some improvements were implemented in the MARS input modelling. These include the use of fine meshes for the bottom region of the steam generator secondary side and proper thermal-hydraulics calculation options. Other input model improvements in the heat loss and the flow restrictor models were also made and the results were investigated in detail. From the results of simulations, the limitations and further improvement areas of the MARS code were identified.
A Survey on the M&V to guarantee the energy saving performance of ESCO
Lim, Ki Choo ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 123~129
DOI : 10.5855/ENERGY.2014.23.4.123
ESCO industry should guarantee the energy saving performance with M&V such as developed countries. The application of the ESCO M&V is a necessary condition on energy saving performance. This study recommends a goal, direction, and order of application and suggests selection of M&V between option A, option B, option C, option D by energy conservation technology in Korea, with reference to the examples from IPMVP and applied in US and Japan. In the future, it is needed to study on the guideline for plan report and result report of M&V based on a goal, direction, and selection of M&V option.
Numerical Study to Develop Low-NO
Multi-nozzle Burner in Rotary Kiln
Ahn, Seok-Gi ; Kim, Jin-Ho ; Hwang, Min-Young ; Kim, Gyu-Bo ; Jeon, Chung-Hwan ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 130~140
DOI : 10.5855/ENERGY.2014.23.4.130
Rotary kiln burner has been developed continuously to improve process efficiency and exhaust emission. In this study, the characteristics of the flame and exhaust emission were numerically analyzed according to the diameter of primary air nozzle, equivalent ratio of burner, and equivalent ratio at center and side nozzle for development of multi-nozzle burner in the COG(Coke Oven Gas) rotary kiln for sintering iron ore. The results indicated that the flame length and
emission increase, as the diameter of primary air nozzle and equivalent ratio of burner increase. And according to the change of equivalent ratio at the center and the side of the nozzle, the flame length and average temperature in the kiln show very little change but the
emission shows obvious difference. In conclusion, the best design conditions which have satisfying flame length, average temperature and
emission are as follows:
is 1.33, equivalent ratio of burner is 1.25 and center nozzle conditions are Rich.
Structure direct agent-assisted hydrothermal synthesis and small gases adsorption behavior of pure RHO zeolite
Kim, Beom-Ju ; Sharma, Pankaj ; Han, Moon-Hee ; Cho, Churl-Hee ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 141~149
DOI : 10.5855/ENERGY.2014.23.4.141
In the present study, pure RHO zeolite was hydrothermally synthesized by using 18-crown-6 ether as a structure directing agent(SDA), and the small gases adsorption was investigated. Synthesized RHO zeolite was a cube shape particle of which average edge length was around
and composed of primary crystallites having a diameter of around 100 to 200 nm. RHO zeolite structure was stable under 3h calcination at
. Water adsorption data announced that RHO zeolite has a specific surface area of 483.32 m2/g and its micropore diameter was about 4 A. Gas adsorption was studied in the pressure range of 50 to 500 kPa for
. It was evident that RHO zeolite showed a strong
adsorption behavior. Especially, RHO zeolite showed a transient
adsorption behavior. The 3h
up-take at 50 kPa and 500 kPa was 1.283 and 3.357 mmol/g, respectively. The
selectivity was around 16 at 500 kPa. Compared with gas adsorption data for some representative microporous adsorbents, it was certain that RHO zeolite is a beneficial adsorbent for
A Mathematical Structure and Formulation of Bottom-up Model based on Linear Programming
Kim, Hu Gon ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 150~159
DOI : 10.5855/ENERGY.2014.23.4.150
Since the release of mid-term domestic GHG goals until 2020, in 2009, some various GHG reduction policies have been proposed. There are two types of modeling approaches for identifying options required to meet greenhouse gas (GHG) abatement targets and assessing their economic impacts: top-down and bottom-up models. Examples of the bottom-up optimization models include MARKAL, MESSAGE, LEAP, and AIM, all of which are developed based on linear programming (LP) with a few differences in user interface and database utilization. In this paper, we suggest a simplified LP formulation and how can build it through step-by-step procedures.
Adsorption of water vapor on zeolites of different framework types and alkali ions
Song, Ju-Sub ; Sharma, Pankaj ; Kim, Beom-Ju ; Kim, Min-Zi ; Han, Moon-Hee ; Cho, Churl-Hee ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 160~168
DOI : 10.5855/ENERGY.2014.23.4.160
In the present study, water vapor adsorption was evaluated at 298.15K for 9 different zeolites having LTA, FAU, CHA, and RHO frameworks, and then effect of framework type, Si/Al molar ratio, and alkali ion type on water up-take was investigated. Zeolites showed water up-takes which were increased in an order of
frameworks. NaY zeolite having FAU framework showed a water up-take of 406 mg/g at p/po=0.5. The up-take was a little larger than that of 13X zeolite with the same framework. Among LTA zeolites, Ca-type 5A zeolite showed the highest water adsorption (282 mg/g at p/po=0.5) which could be explained by the large pore volume. Both CHA zeolite with a Si/Al molar ratio of 2.35 and RHO zeolite with a Si/Al molar ratio of 3.56 showed considerable water up-takes, even though the Si/Al molar ratio was much larger than that of LTA zeolite. In the present study, it is announced that in addition to FAU and LTA zeolites, CHA and RHO zeolites can be a promising dehumidification adsorbent.
The Measurement and Prediction of Combustible Properties for Ethylbenzene
Ha, Dong-Myeong ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 169~175
DOI : 10.5855/ENERGY.2014.23.4.169
For the safe handling of ethylbenzene, this study was investigated the explosion limits of ethylbenzene in the reference data. And the lower flash points, upper flash points and AITs(auto-ignition temperatures) by ignition delay time were experimented. The lower flash points of ethylbenzene by using Setaflash closed-cup and Pensky-Martens closed-cup testers were experimented
, respectively. The lower flash points ethylbenzene by using Tag and Cleveland open cup testers were experimented
, respectively. Also, this study measured relationship between the AITs and the ignition delay times by using ASTM E659 tester for ethylbnezene. The experimental AIT of ethylbenzene was
. The calculated LEL and UEL by using the measured lower flash point and upper flash point were 0.93 Vol.% and 7.96 Vol.%, respectively.
Cost-benefit analysis of project of promoting the economy in Samcheok City
Jeong, Dong-Won ; Jin, Se-Jun ; Han, Jong-Ho ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 176~182
DOI : 10.5855/ENERGY.2014.23.4.176
The project of promoting the economy has attracted attention as on strategy for the economic revitalization of abandoned mine areas which is promoting by local government based on the "Special law on the development of abandoned mine areas". Through the analysis of economic feasibility analysis, the government is trying to determine the presence or absence of budget support to project of promoting the economy of local government. Furthermore, this paper attempts to conduct a cost-benefit analysis, using net present value(NPV), benefit/cost(B/C) ratio, internal rate of return(IRR) techniques for project of promoting the economy of Samcheok City. The project of promoting the economic of Samcheok City is promoting the Yukbaeksan flowers rest park and Glass Art Culture and Tourism theme park. The results indicate that NPV, B/C ratio and IRR of Yukbaeksan flowers rest park are 3,937 million won, 1.06, 6.18% and NPV, B/C ratio and IRR of Glass Art Culture and Tourism theme park are 8,311 million won, 1.34 and 9.47. Accordingly, the projects of promoting the economic of Samcheok City ensure economic feasibility that the three indicators have exceeded 0, 1.0 and 5.5% respectively. Moreover, the analysis results can be used effectively in the decision for the project of promoting ecomony of Samcheok city.
Analysis of leakage factors affecting ECV performance in variable compressor
Mahmud, Md. Iqbal ; Cho, Haeng Muk ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 183~188
DOI : 10.5855/ENERGY.2014.23.4.183
Solenoid operated electromagnetic control valve (ECV) using in an external variable displacement swash plate type compressor is widely used for air conditioning control system because of its low energy consumption and high efficient characteristics. ECV controls the entire vehicle air conditioning system by means of a pulse width modulation (PWM) system that supplied from an external controller. Different pressure ports located within ECV has important functions to control the air/refrigerant flow through its internal passages. The flow paths are preciously maintained with acceptable ranges of leakage (gap) between the parts inside it which is followed by effective design and critical dimensioning of its internal features. Therefore, it saves energy losses from the solenoid operation as well as ensures the balance of forces within it. The research paper highlights analysis of the leakages (at different pressure ports) and dimensioning tolerance factors that affects the ECV performance.
Study on Thermal Efficiency according to Configuration Change and Contact Resistance of Solar Collector with Single Evacuated Tube-type
Choi, Bo-Won ; Yang, Young-Joon ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 189~195
DOI : 10.5855/ENERGY.2014.23.4.189
The use of solar energy among renewable energy tends to increase because of its infinity and cleanness of resources. Even though the consumption rate of solar energy in our country is still low, however, in recent years, the research for solar energy have been widely conducted due to policy support of government. This study was performed to investigate the efficiency of heat collection using solar collector with single evacuated tube-type. As the results, the temperature of radiation fin for solar collector with single evacuated tube-type was lower in spite of high temperature of heat pipe compared that of double evacuated tube-type. In order to increase the efficiency of heat collection, it was confirmed that the loss of heat collection due to contact resistance as well as performance improvement for solar collector should be decreased.
A Study on the Determinants of Technological Level in Korean Bioenergy Firms
Park, Chang-Dae ; Kim, Doo-Chun ; Park, Jung-Gu ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 196~206
DOI : 10.5855/ENERGY.2014.23.4.196
This study analyzes the technological level of Korean bioenergy firms and its determinants by using a multiple logistic regression analysis based on a survey. As the result of analysis, the technological level of Korean bioenergy firms has been positively influenced by the firm size, R&D investments and R&D manpower, but negatively influenced by the competition in domestic market and economy of scale. The policy implications of this study are related to achieve the economy of scale and coevolve between demand and supply-firms for the improvement of the technological level of Korean bioenergy firms.
Combustion Characteristics of Imported Bituminous & Subbituminous Coal in a Pilot Scale Test Facility
Kim, Hyunhee ; Park, Hoyoung ; Lim, Hyunsoo ; Baek, Sehyun ; Kim, Taehyung ; Kim, Youngju ; Gong, Jiseon ; Lee, Jeongeun ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 207~214
DOI : 10.5855/ENERGY.2014.23.4.207
With the depletion of high grade coal, it is indispensable to be used co-combustion of low rank coal with bituminous coal in pulverized coal-fired power plants. This study describes the detailed measurements of combustion characteristics of bituminous and subbituminous coal in a 0.7MWth pilot-scale test facility. This experimental works include the measurement of gas temperature, gas concentrations along with the reactor axial and radial distance at the condition of excess air ratio of 1.2. The solid sampling was carried out and analyzed with the combustion of bituminous coal. The main reaction zone of coal flame in a reactor was formed about 1 m from the swirl burner, and at downstream, the fully developed temperature and species distribution was observed. The sampled particles of bituminous coal in a reactor revealed the complete carbon burn-out was achieved just after an main combustion zone.
Methodology for Describing Different Phase States of Molecular Nitrogen
Cho, Haeng Muk ; Kudryavtsev, I.N. ; Kramskoy, A.V. ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 215~222
DOI : 10.5855/ENERGY.2014.23.4.215
A theory-based methodology for describing the thermodynamic properties of molecular nitrogen is presented. The results obtained indicate a successful application of a fully consistent statistical method for the description of a molecular system in different phase states. The method employs a density of states equation for solid nitrogen and a perturbation potential for gaseous and liquid nitrogen. The main characteristics of the calculation method include the need for a minimal number of initial data and the absence of fitting parameters. The adequacy of the physical model that is the basis for the method allows a description of existing experimental data and the peculiarities of the thermodynamic properties.
Analysis on the Explosion Risk Characteristic of Hydrogen blended Natural Gas
Kang, Seung-Kyu ; Kim, Young-Gu ; Kwon, Jeong-Rak ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 223~229
DOI : 10.5855/ENERGY.2014.23.4.223
This study investigated the explosion characteristics of HCNG fuel using a simulation tool. The damage caused by the storage container explosion and vapor cloud explosion in a gas station was predicted. In case of an vapor cloud explosion in the HCNG station, 50~200kPa explosion pressure was predicted inside the station. When the cylinder explosion was occurred, in case of hydrogen, the measured influential distance of overpressure was 59m and radiant heat was 75m. In case of CNG, influential distance of overpressure was 89m and radiant heat was 144m would be estimated. In case of 30% HCNG that was blended with hydrogen and CNG, influential distance of overpressure was 81m and radiant heat was 130m were measured. The damage distance that explosive overpressure and radiant heat influenced CNG was seen as the highest. HCNG that was placed between CNG and hydrogen tended to be seen as more similar with CNG.
Experimental Study of Vane Expander Prototype Applied to Micro Organic Rankine Cycle
Shin, Dong Gil ; Kim, Young Min ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 230~235
DOI : 10.5855/ENERGY.2014.23.4.230
In this study, performances of the vane expander protype for micro organic Rankine cycle with refrigerant R134a as a working fluid have been analyzed. While operating organic Rankine cycle for analysing expander efficiencies such as overall efficiencies, volumetric efficiencies and mechanical efficiencies under
of expander inlet temperature, the power of the expander, inlet temperature of expander, inlet pressure of expander and the flow rate of the working fluid(refrigerant R134a) have been measured while varying the rotational speed of the expander. It was found that the more the expander revolution speed is high, the more the expander power, overall efficiencies and volumetric efficiencies are higher. In case of 500 rpm of rotational speed, overall efficiencies are 6~7% and in case of 1000 rpm, overall efficiencies are 11~12%. We have found that low volumetric efficiencies result in poor overall efficiencies.
A Generating Cost Evaluation of APR+ Standard Design
Ha, Gag-Hyeon ; Kim, Sung-Hwan ; Lee, Jae-Ho ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 236~239
DOI : 10.5855/ENERGY.2014.23.4.236
KHNP CRI has been developing APR+ nuclear power plant since 2007, which is GEN III+ model with 1500 MWe capacity. To develop safer and more economical nuclear power plant than APR1400, we investigated advanced design features of ALWR(advanced light water reactor) being constructed in Korea and being developed/constructed in foreign countries. We applied the advanced design features and lessons learned from Fukushima accident to develop APR+ standard design suitable for both domestic construction and overseas construction business. Three economic assessments have performed during standard design phase of APR+. The result of the 3th(final) economic analysis for APR+ standard design showed that APR+ N-th plant was about 23% more economical than coal-fired 1,000MW power plant.
A Study on the Heat Loss Reduction of a Refrigerator by Thermal Conductivity Change and Partial Removal of Rubber Magnet
Ha, Ji Soo ; Ahn, Won Sul ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 240~246
DOI : 10.5855/ENERGY.2014.23.4.240
The present study has been carried out to reduce the heat loss from a refrigerator by changing thermal conductivity and partial removal of rubber magnet near refirgerator gasket. To perform this purpose, two dimensional heat transfer analysis for the horizontal cross sectional plane of a refrigerator has been accomplished. From the present study, it could be seen that the heat loss could be reduced nearly 7% by changing thermal conductivity of rubber magnet from 10W/mK to 1W/mK. The heat loss reduction, 17%, could be achieved by removal of rubber magnet near hotline and the effect on the heat loss reduction by partial removal of rubber magnet might be helpful for the refrigerator power consumption.
A Study on the Temperature Characteristics at the Inlet and the Outlet Pipes of a Refrigerator Drain Condenser
Ha, Ji Soo ; Kim, Tae Kwon ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 247~255
DOI : 10.5855/ENERGY.2014.23.4.247
The present study was conducted to elucidate the characteristics of temperature at the inlet and outlet pipes of a refrigerator drain condenser and suggest the method to predict the temperature of the refrigerant at the inlet and outlet pipes of the drain condenser. For this purpose, a built in style refrigerator was installed in a constant temperature chamber to measure temperatures at the inlet and outlet pipes of the drain condenser. From the results of the present analysis, it could be seen that the measured temperatures changed from
and the actual refrigerant temperatures were higher than the measured temperatures with the difference magnitude of
. The present study suggested that the temperatures of the refrigerator could be calculated with the measured temperatures by introducing curve fitting of the measured temperature. The predicted refrigerant temperatures by the present study had the accuracy within 6% error of the actual refrigerant temperatures.
Determination of Optimum Batch Size and Fuel Enrichment for OPR1000 NPP Based on Nuclear Fuel Cycle Cost Analysis
Cho, Sung Ju ; Hah, Chang Joo ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 256~262
DOI : 10.5855/ENERGY.2014.23.4.256
Cycle length of domestic nuclear power plants is determined by the demand-supply plan of utility company. The target cycle length is achieved by adjusting the number of feed fuel assembly and fuel enrichment. Traditionally, utility company first select the number of feed fuel assembly and then find out the fuel enrichment to achieve the special cycle length. But it is difficult to find out if this method is most economical than any other combinations of the enrichment and batch size satisfying the same cycle length. In this paper, core depletion calculation is performed to find out the optimum combination of the enrichment and batch size for given target cycle length in terms of fuel cycle cost using commercial core design code; CASMO/MASTER code. To minimize the uncertainty resulting from transition core analysis, levelized fuel cycle cost analysis was applied to the equilibrium cycle core in order to determine the optimum combination. The sensitivity study of discount rate was also carried out to analyze the levelized fuel cycle cost applicable to countries with different discount rates. From the levelized fuel cycle cost analysis results, the combination with smaller batch size and higher fuel enrichment becomes more economical as the discount rate becomes lower. On the other hand, the combination with higher batch size and lower fuel enrichment becomes more economical as the discount rate becomes higher.
A Study of the Feature Classification and the Predictive Model of Main Feed-Water Flow for Turbine Cycle
Yang, Hac Jin ; Kim, Seong Kun ; Choi, Kwang Hee ;
Journal of Energy Engineering, volume 23, issue 4, 2014, Pages 263~271
DOI : 10.5855/ENERGY.2014.23.4.263
Corrective thermal performance analysis is required for thermal power plants to determine performance status of turbine cycle. We developed classification method for main feed water flow to make precise correction for performance analysis based on ASME (American Society of Mechanical Engineers) PTC (Performance Test Code). The classification is based on feature identification of status of main water flow. Also we developed predictive algorithms for corrected main feed-water through Support Vector Machine (SVM) Model for each classified feature area. The results was compared to estimations using Neural Network(NN) and Kernel Regression(KR). The feature classification and predictive model of main feed-water flow provides more practical methods for corrective thermal performance analysis of turbine cycle.