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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 12, Issue 4 - Nov 2003
Volume 12, Issue 3 - Sep 2003
Volume 12, Issue 2 - Jun 2003
Volume 12, Issue 1 - Feb 2003
Selecting the target year
Development of an Automatic Refrigerant Charging Device for Refrigeration Applications
Journal of Energy Engineering, volume 12, issue 4, 2003, Pages 253~258
Manual type manifold gauge has been used for charging the refrigerant in the refrigeration systems. In this case, the refrigerant is released to the ambient during the hose-switching period. :he objectives of this study are to develop a novel automatic refrigerant charging system, and to quantify the effect of the automatic systems on the reduction of the non-condensable gas and the contamination of the compressor oil. The automatic charging system makes the pressure test, vacuum test, and refrigerant charging work very simple and easy because the charging hose does not have to be switched many times. It is found that the amount of water in the SiO
and the compressor oil reduces to l/4 times of that for the manual type manifold gauge and the refrigerant is not released to the ambient at all when the automatic charging system is adopted.
Numerical Simulation on the Behavior of Air Bubble Discharging into a Water Pool through a Sparger without Load Reduction Ring
Journal of Energy Engineering, volume 12, issue 4, 2003, Pages 259~266
Load reduction ring (LRR) was installed on the ABB-Atom sparger to reduce the oscillatory loadings due to the air bubble clouds in the water pool in case of safety relief system operations. In order to investigate the effect of LRR on the pressure field, a numerical simulation on the behavior of air bubble clouds discharging into a water pool through a ABB-Atom sparser without LRR was performed by using a commercial thermal hydraulic analysis code, FLUENT 4.5. Among the multi-phase models contained in the code, the VOF (Volume Of Fluid) model was used to simulate the interface of water, air and steam flows. By comparing the analysis results with the previous ones, the load reduction ring has an effect on reducing the oscillatory loads at the wall. It also includes the effect of air mass and inlet boundary conditions of the pipe on the pressure oscillations at the wall.
An Experimental Study on the Combustion Characteristics of Wastewater-Emulsion Fuel
Journal of Energy Engineering, volume 12, issue 4, 2003, Pages 267~273
Emulsion fuel is a very attractive fuel because of its energy saving and pollution prevention properties. We investigated and compared the combustion efficiency of B-C oil and emulsion fuel i.e. fuel made from the mixture of B-C oil and waste water. By installing an R-type thermocouple and an optical pyrometer on each side of the boiler, and by placing a combustion analyzer at the point of gas emissions, We were able to measure and compare each flame temperature, combustion rate and the concentration of emitted gas when B-C oil and emulsion fuel are burned. The following results were obtained: The flame temperature of emulsion fuel at the front and rear of the boiler is about 50
lower than the flame temperature of B-C oil. The reason for this difference in temperature is that both latent and sensible heat is lost due to the moisture in the waste water of emulsion fuel. An analysis of emitted gases shows that when emulsion fuel is used polluting substances decrease also the concentration of CO becomes considerably lower. The combustion efficiency for B-C oil and emulsion fuel is 85.5% and 84.8% respectively.
Development of Application for Unit Commitment using the Database
Journal of Energy Engineering, volume 12, issue 4, 2003, Pages 274~280
This paper presents a Case-Sort method to solve the unit commitment problem using database in electric power systems. The formulation of the unit commitment nay be described as nonlinear mixed integer programming. However, it is hard to optimize a problem with discrete and continuous variables in a large-scale system at the same time. The Case-Sort method is based on the unit［MW］generation cost considered drive hour. Then, this paper shows effectiveness and economical efficiency of the proposed algorithm.
A Subchannel Analysis Code for LMR Core Subassembly Thermal Hydraulic Analysis: The MATRA-LMR
Lim, Hyun-Jin ; Kim, Young-Gyun ; Kim, Yeong-Il ; Oh, Se-Kee ;
Journal of Energy Engineering, volume 12, issue 4, 2003, Pages 281~288
The MATRA-LMR code has been developed based on a subchannel analysis method for LMR (Liquid Metal Reactor) core subassembly thermal hydraulic design and analysis. The code was improved to allow a seven assembly calculation and can account for inter-assembly heat transfer based on a lumped parameter model. This paper describes the main modifications and improvements of the code and shows reference calculation results which compared single assembly calculation with seven assembly calculation cased for driver and blanket subassemblies of the KALIMER 150 MWe breakeven conceptual design core. KAL- IMER is a pool-type sodium cooled reactor with a thermal output of 392.0 MWth, which have inherently safe, environmentally friendly, proliferation-resistant and economically viable reactor concepts.
Conceptual Design of 50 kW thermal Chemical-Looping Combustor and Analysis of Variables
Journal of Energy Engineering, volume 12, issue 4, 2003, Pages 289~301
To develop a chemical-looping combustion technology, conceptual design of 50 kW thermal chemical-looping combustor, which is composed of two interconnected pressurized circulating fluidized beds, was performed by means of mass and energy balance calculations. A riser type fast fluidized bed was selected as an oxidizer and a bubbling fluidized bed was selected as a reducer by mass balance for the chemical-looping combustor. Calculated values of bed mass, solid circulation flux, and reactor dimension by mass and energy balance calculations were suitable for construction and operation of chemical-looping combustor. It is concluded from the comparison of the design results and operating values of commercial circulating fluidized bed that the process outline is realistic. Moreover, the previous results support that oxygen carrier particle, NiO/bentonite, fulfills the conversion rates needed for the proposed design. The effects of system capacity, metal oxide content in a oxygen carrier particle, amount of steam input, gas velocity, and solid depth on design values were investigated and the changes in the system performance can be estimated by proposed design tool.
A Study on the Reactivity of Zinc-based Sorbents Using Yellow Earth as Support at Middle Temperatures
Journal of Energy Engineering, volume 12, issue 4, 2003, Pages 302~308
The peformence tests of zinc-based desulfurization sorbents using the yellow earth as support for the hot gas clean up were carried out. The zinc-based sorbent with 25 wt％ yellow earth was prepared, and their properties such as the reaction rate, the sulfur capacity and the attrition resistance, were investigated. The reactivity tests for hot gas desulfurization was performed at middle temperatures (sulfidation/regeneration：480
). During multi-cyclic desulfurization, the deactivation of zinc-based sorbent was decreased by the addition of yellow earth, and their efficiency was enhanced. The ZnO/yellow earth sorbent had high reactivity, good regenerability, long-term durability (about 19 gS/100 g sorbent for 10-cycles) and high attrition resistance (AI=19.1％). It was concluded that the peroperties of zinc-based sorbent were improved by metal oxides (Fe
, etc) in the yellow earth. From these results, it was confirmed that the desulfurization properties of zinc-based sorbents at middle temperatures could be improved by the yellow earth using as support.
Distribution Feeder Aspects of a Variable Speed Wind Turbine in Voltage Fluctuations and Harmonics
Journal of Energy Engineering, volume 12, issue 4, 2003, Pages 309~319
The main purpose of this paper is to present a simulation model for assessing the impacts of a variable speed wind turbine (VSWT) on the distribution network and perform a simulation analysis of volt-age profiles and harmonics along the wind turbine installed feeder using the presented model. The modeled wind energy conversion system consists of a fixed pitch wind turbine and a permanent-magnet synchronous generator, in which a controllable power electronics inverter performs variable speed operation and reactive power output control. Impact analysis on voltage profiles and harmonics of a VSWT-installed distribution feeder is addressed and simulated in terms of steady state and dynamic behaviors. Various capacities and different modes of variable speed wind turbines are simulated and investigated. Case studies demonstrate how feeder voltages are influenced by capacity and control modes of wind turbines and changes in wind speed under various network conditions, and show harmonic impacts on the feeder. Modeling and simulation analysis is based on PSCAD/EMTDC a software package.
Combustion and NOx Emission Characteristics of the Gas Turbine Combustor Burning Medium-Btu Gas as Alternative Fuel
Journal of Energy Engineering, volume 12, issue 4, 2003, Pages 320~327
A CFD (Computational fluid Dynamics) research is conducted for the investigation of the fuel alteration of MBTU (medium-Btu) gas in IGCC gas turbine combustor. The computational analysis method of the gas turbine combustor is constructed by incorporating MBTU gas reaction and fuel NOx models into commercial CFD code. With the use of the present analysis method, comparisons are made on the flow velocity, the chemical species and the temperature distributions, and on the flame shape and behavior of gas turbine combustor firing natural gas and MBTU gases (coal gas, heavy residue oil gas). Furthermore, the NOx formation characteristics and the turbine matching condition of the combustor are analyzed. Based on the computed analysis results, the present study provides the directions for the redesign and the design modification of IGCC gas turbine combustor firing MBTU gas as alternative fuel.
A Study of Unaccounted-for Gas Volume : Seoul, Kyunggi Area
Journal of Energy Engineering, volume 12, issue 4, 2003, Pages 328~338
A study is perfomed on the difference between the volume of gas purchased from Korea Gas Corporation (KGC) and that of measured gas deliveries including total sales, pipeline inventory, and other usage by gas companies at Seoul and Kyunggi area. Actual data md information from 1996 to 2001 on gas purchase from KGC, sales, loss and own company use and pipeline status of each gas company are used to identify net inventory change in pipeline, unaccounted inventory estimates based on billing cycle and their net changes. A framework to be used for the analysis of such differences and an empirical test result are being provided. As a conclusion, the hypothesis that each gas company purchased more than the volume of gas accounted-for by all the possible factors is shown to be rejected.