Go to the main menu
Skip to content
Go to bottom
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 21, Issue 12 - Dec 2009
Volume 21, Issue 11 - Nov 2009
Volume 21, Issue 10 - Oct 2009
Volume 21, Issue 9 - Sep 2009
Volume 21, Issue 8 - Aug 2009
Volume 21, Issue 7 - Jul 2009
Volume 21, Issue 6 - Jun 2009
Volume 21, Issue 5 - May 2009
Volume 21, Issue 4 - Apr 2009
Volume 21, Issue 3 - Mar 2009
Volume 21, Issue 2 - Feb 2009
Volume 21, Issue 1 - Jan 2009
Selecting the target year
Simulation of the Refrigeration Cycle Equipped with a Non-Adiabatic Capillary Tube
Park, Sang-Goo ; Son, Ki-Dong ; Jeong, Ji-Hwan ; Kim, Lyun-Su ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 21, issue 3, 2009, Pages 131~139
The simulation of refrigeration cycle is important since the experimental approach is costly and time-consuming. The present paper focuses on the simulation of a refrigeration cycle equipped with a capillary tube-suction line heat exchanger(SLHX), which is widely used in small vapor compression refrigeration systems. The present simulation is based on fundamental conservation equations of mass, momentum, and energy. These equations are solved through an iterative process. The non-adiabatic capillary tube model is based on homogeneous two-phase flow model. This model is used to understand the refrigerant flow behavior inside the non-adiabatic capillary tube. The simulation results show that both of the location and length of heat exchange section influence the coefficient of performance (COP).
An Assessment of Friction Factor and Viscosity Models for Predicting the Refrigerant Characteristics in Adiabatic Capillary Tubes
Son, Ki-Dong ; Park, Sang-Goo ; Jeong, Ji-Hwan ; Lee, Sung-Hong ; Kim, Lyun-Su ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 21, issue 3, 2009, Pages 140~148
Capillary tubes are widely used as expansion device in small refrigeration systems. The refrigerant flowing in the capillary tube experiences frictional and accelerational head losses and flashing simultaneously. In this paper flow characteristics of adiabatic capillary tubes were simulated with various friction factor models, two-phase viscosity models, and two-phase frictional multiplier models. The predicted pressure distribution and mass flow rate are compared with experimental data reported in literature. It is confirmed that the predicting accuracy with homogeneous model can be improved by employing suitable correlations of friction factor, two-phase viscosity and two-phase frictional multiplier.
A Study on the Performance of Thermoelectric Cooling System for Design Parameters of the Cooling Jacket
Park, Sang-Hee ; Lee, Jeong-Eun ; Kim, Kyoung-Jin ; Kim, Dong-Joo ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 21, issue 3, 2009, Pages 149~156
A small-scale thermoelectric cooling system was built in an effort to enhance the performance of the refrigeration system by utilizing the water-cooled jacket which was attached to the hot side of the thermoelectric module. Considered design parameters for the water-cooled jacket were the geometry of the flow passage inside the jacket and the flow rate of cooling water. The higher flow rate of cooling water in the jacket resulted in a better performance of the refrigeration system. The increase in the number of channels for water flow passage inside the cooling jacket also showed significant improvement on the performance of the thermoelectric cooling system such as the cooling capacity and the COP of the refrigeration system.
Computational Studies on the Combustion and Thermal Performance of the Coal Fired Utility Boiler : Temperature and Thermal Energy Distribution
Seo, Sang-Il ; Park, Ho-Young ; Lee, Sung-No ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 21, issue 3, 2009, Pages 157~166
The pulverized coal combustion behavior in the coal fired utility boiler has been investigated with the CFD and process analysis techniques. The used commercial software were CFX and PROATES, and these were coupled each other to get more reliable boundary condition set-up, resulting in more reliable solution. For two cases which were the actual operation condition of A power plant, the calculated values from the coupled CFD and process analysis for thermal energy system were compared with the plant data, and the good agreements were obtained for Case 1 and 2. The calculated temperature distributions on the surface of heat exchangers were compared with the plant data for the steam temperatures across heat exchangers, and these explained the actual operating situation very well. The temperature deviation across the final superheater tube, which was believed to be the main cause of the frequent tube failure, were also explained very well with the calculated distributions of gas temperature and radiation on the plane of the final superheater.
External Condensation Heat Transfer Coefficients of R245fa on Low Fin and Turbo-C Tubes
Shim, Yun-Bo ; Park, Ki-Jung ; Jung, Dong-Soo ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 21, issue 3, 2009, Pages 167~175
In this study, condensation heat transfer coefficients(HTCs) of R22, R123, R134a and R245fa are measured on both 26fpi low fin and Turbo-C tubes. All data are taken at the vapor temperature of
with a wall subcooling of
. Test results show that HTCs of the newly developed low vapor pressure alternative refrigerant, R245fa, are
higher than those of R123 for 26fpi low fin tube and Turbo-C tube respectively. For all refrigerants tested, HTCs of Turbo-C enhanced tube are higher than those of 26fpi low fin tube. For the low fin tube, Beatty and Katz's prediction equation yielded 20% deviation for all fluids. The heat transfer enhancement ratio of R245fa on the Turbo-C tube is
while that of R123 is
. From the view point of environmental safety and condensation heat transfer, R245fa is a long term candidate to replace R123 currently used in centrifugal chillers.
Flow Distribution in Manifold Using Modified Equal Pressure Method
Ye, Huee-Youl ; Kim, Doo-Hwan ; Lee, Kwan-Soo ; Cha, Woo-Ho ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 21, issue 3, 2009, Pages 176~185
A general flow distribution model and a simple process of numerical analysis, which can be applied to multi-pass systems with manifolds, are presented. A numerical procedure, namely a modified equal pressure method based on the discrete model, was developed to predict flow rates at branch tubes. The predicted pressure distribution agreed well with the previous research with the average error less than 11%. A parametric study was performed to demonstrate the effect on the flow distribution.
A Study on the Effective Fire and Smoke Control in Road-Tunnel with Semi-Transverse Ventilation
Jeon, Yong-Han ; Yoo, Ji-Oh ; Kim, Nam-Jin ; Seo, Tae-Boem ; Kim, Jong-Yoon ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 21, issue 3, 2009, Pages 186~192
In this study it is intended to review the moving characteristics of smoke by performing visualization for calculation of the optimal smoke exhaust air volume in case a fire occurs in tunnels where transverse ventilation is applied, and to obtain basic data necessary for design of the smoke exhaust systems by deriving optimal smoke exhaust operational conditions under various conditions. As a result of this study, if it was assumed 0 critical velocity in the tunnel, the smoke exhaust air volume was limited within 250 meter in the road-tunnel disaster prevention indicator and the exhaust efficiency was from 55.1% to 95.8% in the result of this study. In case of oversized exhaust ports, the generated smoke is more than the case of uniform exhaust. When the critical velocity in the tunnel is 1.75 m/s and 2.5 m/s, the optimal smoke exhaust air volume has to be more than
for the distance of the moving smoke which can limit the distance to 250 m.
A Study on the Indoor Airflow Pattern by Changing the Location of Mechanical Terminal Unit
Choi, Jeong-Min ; Cho, Sung-Woo ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 21, issue 3, 2009, Pages 193~200
The ventilation system of apartments can be divided by supply and exhaust fan, supply fan and exhaust free and supply free and exhaust fan. Recently, the individual ventilation system and central ventilation system which is combined cooling system with duct system are applied to apartment ventilation system. The airflow pattern is affected by location of supply unit and exhaust unit in indoor. This study is to investigate the proper distance between supply unit and exhaust unit using CFD. As a result of this study, the proper distance between supply unit and exhaust unit could be suggested at the interval of 3 m in supply and exhaust fan system and 2.5 m in supply fan and exhaust free.
Suggestion of the Worth Evaluation of Cool Air and the Allocation Methodology of Cooling Cost
Kim, Deok-Jin ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 21, issue 3, 2009, Pages 201~208
Our government will make a plan regulating the cooling limit temperature of the summer season to 26 degree and the heating limit temperature of the winter season to 20 degree for energy saving. Where, the key point of this politic pursuit can be the charge system on heating and cooling cost. We have suggested new cost allocation methodology as a worth evaluation method in the precedent study, and preformed the worth evaluation and cost allocation on four kind of warm air produced from a heating system as an example. In this study, we applied the suggested method to four kind of cool air, and preformed the worth evaluation and cost allocation on each cool air. As a result, similarly to the precedent study, the more energy a customer saved, the more cooling unit cost decreased, and the more energy a customer consumed, the more cooling unit cost increased. From this analysis, we hope that the suggested methodology can offer a theoretical basis to the energy charge policy of government, and induce the spontaneous energy saving of consumers.