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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 20, Issue 12 - Dec 2008
Volume 20, Issue 11 - Nov 2008
Volume 20, Issue 10 - Oct 2008
Volume 20, Issue 9 - Sep 2008
Volume 20, Issue 8 - Aug 2008
Volume 20, Issue 7 - Jul 2008
Volume 20, Issue 6 - Jun 2008
Volume 20, Issue 5 - May 2008
Volume 20, Issue 4 - Apr 2008
Volume 20, Issue 3 - Mar 2008
Volume 20, Issue 2 - Feb 2008
Volume 20, Issue 1 - Jan 2008
Selecting the target year
A Numerical Study on the Smoke Control in Side-Platform Type Subway Station Fires
Lee, Sung-Ryong ; Ryou, Hong-Sun ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 2, 2008, Pages 81~86
In this study, numerical simulations were carried out to analyze the effect of the smoke extraction system and fire shutters in subway station fires using FDS 4.0. Subway station used in the experiment was 205 m long. Simulation results are validated by comparing with experimental results. Simulation results showed good agreement with experimental results within
. 20 MW polystyrene was used as a fuel in the numerical prediction. Numerical predictions were performed in the side-platform type subway station in case of a train fire. Temperature and CO concentration were lowered by the operation of smoke extraction system.
Flow Condensation Heat Transfer Characteristic of R245fa in a Horizontal Plain Tube
Park, Hyun-Shin ; Park, Ki-Jung ; Jung, Dong-Soo ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 2, 2008, Pages 87~96
Flow condensation heat transfer coefficients(HTCs) of R123 and R245fa are measured in a horizontal plain tube. The main test section in the experimental flow loop is made of a plain copper tube of 9.52 mm outside diameter and 530 mm length. The refrigerant is cooled by passing cold water through an annulus surrounding the test section. Tests are performed at a fixed saturation temperature of
with mass fluxes of 50, 100,
and heat flux of
. Heat transfer data are obtained in the vapor quality range of
. Test results show that the flow condensation HTCs of R245fa are overall 7.9% higher than those of R123 at all mass fluxes. The pressure drop of R245fa is smaller than that of R123 at the same heat flux. In conclusion, R245fa is a good candidate to replace ozone depleting R123 currently used in chillers from the view point heat transfer and environmental properties.
An Evaluation of Chiller Control Strategy in Ice Storage System for Cost-Saving Operation
Lee, Kyoung-Ho ; Choi, Byoung-Youn ; Lee, Sang-Ryoul ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 2, 2008, Pages 97~105
This paper presents simulated and experimental test results of optimal control algorithm for an encapsulated ice thermal storage system with full capacity chiller operation. The algorithm finds an optimal combination of a chiller and/or a storage tank operation for the minimum total operation cost through a cycle of charging and discharging. Dynamic programming is used to find the optimal control schedule. The conventional control strategy of chiller-priority is the baseline case for comparing with the optimal control strategy through simulation and experimental test. Simulation shows that operating cost for the optimal control with chiller on-off operation is not so different from that with chiller part load capacity control. As a result from the experimental test, the optimal control operation according to the simulated operation schedule showed about 14 % of cost saving compared with the chiller-priority control.
Experimental Study on Evaporation Heat Transfer and Oil Effect in Micro-fin Tube Using
Lee, Sang-Jae ; Choi, Jun-Young ; Lee, Jae-Heon ; Kwon, Young-Chul ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 2, 2008, Pages 106~112
In this paper, the experimental results on evaporation heat transfer characteristics were reported for a micro-fin tube using
. An experimental refrigerant loop had been established to measure the evaporation heat transfer coefficient and pressure drop of
. Experiments were conducted for mass fluxes, heat fluxes, saturation temperatures and PAG oil concentrations. With increasing the heat flux and the saturation temperature, the evaporation heat transfer coefficient increased. At the higher mass flux, however, the exit vapor quality of the micro-fin tube was to be lower. The peak of the heat transfer coefficient was shifted toward low quality region. The evaporation pressure drop increased as the mass flux increased and the saturation temperature decreased. As PAG oil concentration increased, the evaporation heat transfer coefficient decreased and the dryout was delayed by oil addition.
Conceptual Design of the Scroll Air Compressor for Fuel Cell
Kwon, Tae-Hun ; Ahn, Jong-Min ; Kim, Hyun-Jin ; Shim, Jae-Hwi ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 2, 2008, Pages 113~120
Potential application of the scroll type machine to air compressor for fuel cell has been studied. Among the seven configuration factors which determine scroll wrap profile, the wrap thickness and the orbiting radius were chosen as two independent variables to generate various scroll wrap profiles. A conceptual design practice was conducted for scroll air compressor for SOFC with power output of 2 kW. With larger wrap thickness and orbiting radius, base plate area of the orbiting scroll becomes smaller, so is the axial gas force acting on the base plate, resulting in reduced thrust loss in spite of larger friction velocity. Performance analysis on the designed model showed that its total efficiency was 64.4% with the mass flow rate per unit compressor input of 0.00905 kg/(s kW) for the wrap thickness of 3.5 mm and the orbiting radius of 3.0 mm.
Modeling of Turbulent Ventilation through an Opening due to Outdoor Pressure Fluctuations
Han, Hwa-Taik ; Yom, Chol-Min ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 2, 2008, Pages 121~127
This paper investigates the effects of outdoor pressure fluctuations on natural ventilation through an opening on a building envelope. The ventilation airflow rate depends on the magnitude and the period of the pressure fluctuations, the size of the opening relative to the space volume, and the resistance characteristics of the opening. Non-dimensional parameters have been derived, which determine indoor pressure responses due to outdoor pressure fluctuations. The flow regions are categorized into (1) synchronized region, (2) opening resistance region, and (3) transition region depending on the non-dimensional parameter derived. Pressure fluctuations and flow characteristics are investigated numerically using the 4th order Runge-Kutta method.
A Study on Estimation of Cooling Load for Effective Control of Ice Thermal Storage System
Yoo, Seong-Yeon ; Han, Kyu-Hyun ; Lee, Je-Myo ; Han, Seung-Ho ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 2, 2008, Pages 128~136
It is necessary to estimate the cooling load of the next day for effective control of ice thermal storage system. In this paper, new methodology is proposed to estimate the cooling load using design parameters of building and predicted weather data. Only six input parameters such as sensible heat coefficient and constant, latent heat coefficient and constant, maximum and minimum temperature are necessary to obtain hourly distribution of cooling load for the next day. Two benchmarking buildings(hospital and research institute) are selected to validate the performance of the proposed method, and the estimated cooling loads in hourly and daily bases are calculated and compared with the measured data for E hospital. The estimated results show fairly good agreement with the measured data for both buildings.
Numerical Simulation of a Forest Fire Spread
Lee, Myung-Sung ; Won, Chan-Shik ; Hur, Nahm-Keon ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 2, 2008, Pages 137~143
In the present study, a forest fire spread was simulated with a three-dimensional, fully-transient, physics-based, computer simulation program. Physics-based fire simulation is based on the governing equations of fluid dynamics, combustion and heat transfer. The focus of the present study is to perform parametric study to simulate fire spread through flat and inclined wildland with vegetative fuels like trees or grass. The fire simulation was performed in the range of the wind speeds and degrees of inclination. From the results, the effect of the various parameters of the forest fire on the fire spread behavior was analyzed for the future use of the simulation in the prediction of fire behavior in the complex terrain.
A Numerical Analysis on the Flow Characteristics and the Collection Efficiency for Fine Particles in a Cyclone
Yong, Jung-Kwon ; Kim, Chang-Nyung ; Jo, Young-Min ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 2, 2008, Pages 144~153
A numerical analysis has been carried out to examine the flow characteristics and the collection efficiency for fine particles in a cyclone using Computational Fluid Dynamics (CFD) technique. The cyclone with the cylinder diameter of 60 mm has been considered for the investigation of the particle collection in a relatively smaller cyclone with somewhat higher inlet air velocities. Fundamental air flow patterns for different inlet velocities have been calculated and then the motions of particles of different sizes have been obtained. The calculated collection efficiencies for fine particles are compared with the experimental results, which shows a good agreement. The current result can be used for the design of cyclones with high collection efficiency.