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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Korean Journal of Air-Conditioning and Refrigeration Engineering
Journal Basic Information
Journal DOI :
The Society of Air-Conditioning and Refrigerating Engineers of Korea
Editor in Chief :
Volume & Issues
Volume 22, Issue 12 - Dec 2010
Volume 22, Issue 11 - Nov 2010
Volume 22, Issue 10 - Oct 2010
Volume 22, Issue 9 - Sep 2010
Volume 22, Issue 8 - Aug 2010
Volume 22, Issue 7 - Jul 2010
Volume 22, Issue 6 - Jun 2010
Volume 22, Issue 5 - May 2010
Volume 22, Issue 4 - Apr 2010
Volume 22, Issue 3 - Mar 2010
Volume 22, Issue 2 - Feb 2010
Volume 22, Issue 1 - Jan 2010
Selecting the target year
A Numerical Study on Passenger Evacuation in a Subway Station in Case of Fire Occurrence
Kim, Chi-Gyeom ; Lee, Sung-Won ; Hur, Nahm-Keon ; Nam, Seong-Won ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 8, 2010, Pages 509~514
A numerical simulation of passenger evacuation in a subway station was performed by coupling the passenger flow analysis and the fire simulation. The algorithm of the passenger flow analysis was based on a DEM (Discrete Element Method) using the potential map of the direction vector for each passenger. This algorithm was improved in the present study as to use finer grid smaller than a passenger in order to resolve detailed geometry of the station and to resolve the behavior of passengers in the bottleneck at the ticket gate considering the collision of passengers to a wall or with other passengers. In the fire simulation, the CO distribution predicted by using CFD was used to take into account the effect of toxic gases on the passengers' mobility. The methodology proposed in the present study could be used in designing safer subway station in case of fire occurrence.
The Intelligent Control Algorithm of a Transformer Cooling System
Han, Do-Young ; Won, Jae-Young ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 8, 2010, Pages 515~522
In order to improve the efficiency of a transformer cooling system, the intelligent algorithm was developed. The intelligent algorithm is composed of a setpoint algorithm and a control algorithm. The setpoint algorithm was developed by the neural network, and the control algorithm was developed by the fuzzy logic. These algorithms were used for the control of a blower and an oil pump of the transformer cooling system. In order to analyse performances of these algorithms, the dynamic model of a transformer cooling system was used. Based on various performance tests, energy savings and stable controls of a transformer cooling system were observed. Therefore, control algorithms developed for this study may be effectively used for the control of a transformer cooling system.
A Numerical Study on Flow Characteristics Around Rectangular Cylinder with Different Width-to-height Ratios
Park, Yong-Gap ; Son, Chang-Min ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 8, 2010, Pages 523~529
We investigate two-dimensional laminar flow around rectangular cylinders placed in a uniform stream. Numerical simulations are performed, using finite volume method, in the ranges of
, where Re and W/H are the Reynolds number and the width-to-height ratio, respectively. The immersed boundary method is used to handle the rectangular cylinder in a rectangular grid system. Comparisons with the previous results show good agreement in Strouhal number, drag and lift coefficient. The present study reports the detailed information of flow structure at different width-to-height ratios in the ranges of
Viability of HVAC System for Energy Conservation in High Density Internal-load Dominated Buildings
Cho, Jin-Kyun ; Jeong, Cha-Su ; Kim, Byung-Seon ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 8, 2010, Pages 530~537
With the advancement of technology, the density of IT equipment, heat load and power consumption continue to increase in high density internal-load dominated buildings as datacenters. To improve the HVAC system's energy performance and efficiency, there is a need to find methods of using outside air. Through cooling tower control that is based on outside wet-bulb temperature, the water-side economizer made it possible to achieve a maximum energy performance improvement of about 16.6% over the basic chilled water system, whereas the air-side economizer, through control based on outdoor air enthalpy, made it possible to achieve about 42.4% improvement.
Impingement Heat Transfer Within a Row of Submerged Circular Water Jets
Ohm, Ki-Chan ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 8, 2010, Pages 538~544
An experimental investigation is presented to study the effect nozzle spacing, jet to plate spacing and Reynolds number on the local heat transfer to normally upward impinging submerged circular water jets on a flat heated surface. Nozzle arrays are a single jet(nozzle dia. = 8 mm), a row of 3 jets(nozzle dia. = 4.6 mm, nozzle spacing = 37.5 mm) and a row of 5 jets(nozzle dia. = 3.6 mm, nozzle spacing = 25 mm), and jet to plate spacing ranging from 16∼80 mm(H/D = 2∼10) is tested. Reynolds number based on single jet exit condition is varied 30000∼70000(
= 3∼7 m/s). Except for the condition of H/D = 10, the average Nusselt number of multi-jet is higher than that of single jet. For H/D = 2, average Nusselt number is increased by 50.3∼82.5% for a row of 3 jets and by 52.9∼65.2% on a row of 5 jets when compared to the average Nusselt number on the single jet.
Analysis of the Influence of Post-Combustion
Capture on the Performance of Fossil Power Plants
Tak, Sang-Hyun ; Kim, Tong-Seop ; Chang, Young-Soo ; Lee, Dae-Young ; Kim, Min-Sung ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 8, 2010, Pages 545~552
Research and development efforts to reduce
emission are in progress to cope with global warming.
emission from fossil fuel fired power plants is a major greenhouse gas source and the post-combustion
capture is considered as a short or medium term option to reduce
emissions. In this study, the application of the post-combustion
capture system, which is based on chemical absorption and stripping processes, to typical fossil fuel fired power plants was investigated. A coal fired plant and a natural gas fired combined cycle plant were selected. Performance of the MEA-based
capture system combined with power plants was analyzed and overall plant performance including the energy consumption of the
capture process was investigated.
The Influence of Illuminance Variation by a Daylight Dimming Control System on Visual Comfort Under Clear Sky Conditions
Kim, Soo-Young ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 8, 2010, Pages 553~561
This study examines the influence of light variation on visual responses in a small office space where a daylight dimming control system is applied. Field measurements and survey were performed in a full-scale mocked-up small office space under clear sky day conditions. Maximum fluctuation range for desktop was 133.5 lx and it just happened once for entire monitoring period. For the majority of time, the fluctuation range did not exceed 50 lx, which did not cause visual discomfort to subjects. The daylight dimming control system successfully kept required illuminance levels for an office environment when desktop illuminance by daylight ranged up to 300 lx. The most serious contributor to the sensation of glare was direct daylight through window. The dimming of electric light was not a significant contributor to visual discomfort for the subjects under clear sky day conditions. Visual comfort was significantly influenced by the sensation of glare, feeling for visual stimulation and distraction, and required illuminance level.
A Numerical Study on Solidity Characteristics of the Cross-flow Power Turbine(CPT)
Chung, Kwang-Seop ; Kim, Chul-Ho ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 8, 2010, Pages 562~566
Wind energy is one of the most general natural resources in the world. However, as of today, generating electricity out of wind energy is only available from big wind generator, Furthermore, an axial-flow turbine is the only way to produce electricity in the big wind generator. This paper is for the guidance of drawing impact fact about power turbine using cross-flow type transferring wind energy to electricity energy. It will find the ideal value which enables to make cross-flow power turbine(CPT) using computational fluid dynamics(CFD) code. This study tries to analyze the "Solidity" characteristics. We can find out turbine-blade number through CFD. CFD is using "Fluent_ver 6.3.16", and the data from its result will judge fan-blade performance through specific torque and specific power from each "Solidity" model. Based upon the above, we will make cross-flow power turbine of multi-blade centrifugal fan instead of axial-flow type.
An Experimental Study on the Operating Performance of an Air Shift type Heat Pump with Heat Exchanger
Jang, Young-Keun ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 8, 2010, Pages 567~572
Air shift type heat pump is combined heat recovery ventilator and refrigerator, and it is installed an air shifter changing air flow. And so it is an perfect AHU(Air Handling Unit) capable to cooling, heating, ventilation and heat recovery. Therefore, an experimental study has been carried out to investigate the operating performance in winter for this system. An experimental data are room temperature, inlet/outlet temperature of condenser, evaporator and heat exchanger. They have been measured as the variation of outdoor temperature. The results, in case of rising above freezing, the air shift type heat pump system is operated normally, and the heating COP is 3.0~4.2 by varying outdoor temperature from
A Study on the Analysis of Incompressible and Looped Flow Network Using Topological Constitutive Matrix Equation
Yoo, Seong-Yeon ; Kim, Bum-Shin ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 8, 2010, Pages 573~578
Topological matrix which reflects characteristics of network connectivity has been widely used in efficient solving for complicated flow network. Using topological matrix, one can easily define continuity at each node of flow network and make algorithm to automatically generate continuity equation of matrix form. In order to analyze flow network completely it is required to satisfy energy conservation in closed loops of flow network. Fundamental cycle retrieving algorithm based on graph theory automatically constructs energy conservation equation in closed loops. However, it is often accompanied by NP-complete problem. In addition, it always needs fundamental cycle retrieving procedure for every structural change of flow network. This paper proposes alternative mathematical method to analyze flow network without fundamental cycle retrieving algorithm. Consequently, the new mathematical method is expected to reduce solving time and prevent error occurrence by means of simplifying flow network analysis procedure.