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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 18, Issue 12 - Dec 2006
Volume 18, Issue 11 - Nov 2006
Volume 18, Issue 10 - Oct 2006
Volume 18, Issue 9 - Sep 2006
Volume 18, Issue 8 - Aug 2006
Volume 18, Issue 7 - Jul 2006
Volume 18, Issue 6 - Jun 2006
Volume 18, Issue 5 - May 2006
Volume 18, Issue 4 - Apr 2006
Volume 18, Issue 3 - Mar 2006
Volume 18, Issue 2 - Feb 2006
Volume 18, Issue 1 - Jan 2006
Selecting the target year
Optimization of Convective Trapezoidal Profile Fin having Fluid inside the Wall
Jeong Byung-Cheol ; Lee Sung-Joo ; Yoon Sea-Chang ; Kang Hyung Suk ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 18, issue 2, 2006, Pages 95~102
This study analyzes and optimizes a design for a trapezoidal profile straight fin using one-dimensional analytical method. The heat transfer, fin length and fin height are optimized as a function of fin volume, fin shape factor and fin base length. In this optimization, convection characteristic number over fin surface and that of fluid inside fin wall are considered. One of the results shows that the maximum heat loss increases as fin volume increases and both fin shape factor and fin base length decrease.
Experimental and Numerical Analyses of Unsteady Tunnel Flow in Subway Equiped with Platform Screen Door System
Kim Jung-Yup ; Kim Kwang-Yong ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 18, issue 2, 2006, Pages 103~111
To optimize the ventilation and smoke control systems in subway equipped with platform screen door, the technology to analyze the unsteady tunnel flow caused by running of train should be developed. The development of model experiment and numerical analysis technique with relation to unsteady flow of subway were presented. The pressure and air velocity changes in 1/20-scaling experiment unit were measured and results were comparied to those of 3-D unsteady numerical analysis applied with sharp interface method. The experimental and numerical results were quantitatively similar and it would be reasonable to apply sharp interface method to analyze the unsteady flow in subway equipped with platform screen door.
A Development of Coupled Simulation Tool to Evaluate Performance of Ventilation System
Cho Wang-Hee ; Song Doo-Sam ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 18, issue 2, 2006, Pages 112~121
To evaluate the performance of ventilation system properly, the correlations among the ventilation rate, indoor air-quality and cooling/heating load should be analysed. In this study, simulation tool to analyze the performance of ventilation system was developed. The simulation tool is based on the TRNSYS and some modules to calculate concentration of pollutants with the operation of ventilation system and to decide the signal of ventilation system were newly developed in this study. And these modules coupled with building load and heating/cooling simulation modules. To verify the validity of developed simulation tool, comparison study between simulation and field study were accomplished. As results, the simulation tool developed in this study can be used to predict the performance of ventilation system with accuracy.
Characteristic of Frost Growth on a Cold Cylinder Surface in Cross Flow
Yang Dong-Keun ; Kim Min-Soo ; Lee Kwan-Soo ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 18, issue 2, 2006, Pages 122~128
In this paper, frosting experiments were conducted with variations of frosting parameters in order to obtain the correlations of frost properties. As a result, the local thickness, density, and surface temperature of the frost layer were presented. The dimensionless correlations for the frost thickness, frost density, frost surface temperature and heat transfer coefficient were derived as functions of dimensionless frosting parameters by using a dimensional analysis.
A Method to Reduce Flow Depth of a Plate Heat Exchanger without a Loss of Heat Transfer Performance
Song Gwi-Eun ; Lee Dae-Young ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 18, issue 2, 2006, Pages 129~136
Optimal design of an air-to-liquid finned plate heat exchanger is considered theoretically in this study. Based on existing correlations for the pressure loss and the heat transfer in channel flows, the optimal configuration of the plate heat exchanger including the optimal plate pitch and the optimal fin pitch is obtained to maximize the heat transfer within the limit of the pressure drop for a given flow depth of the plate heat exchanger. It is found that the optimal fin pitch is about one ninth of the optimal plate pitch. In the optimal configuration, the flow and thermal condition in the channels is just at the boundary between the laminar developing and laminar fully developed states. It is also found when reducing the flow depth of plate heat exchangers for compactness, the heat transfer performance can be maintained exactly the same if the geometric parameters such as the plate thickness, plate pitch, fin thickness, and fin pitch are reduced proportional to the square root of the flow depth as long as the flow keeps laminar within the heat exchangers.
A Numerical Study on the Behavior Characteristics of Ethylbenzene and 1, 2, 3-Trimethylbenzene in a Conference Room
Lee, Chang-Geun ; Jeong, Jin ; Kim, Chang-Nyung ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 18, issue 2, 2006, Pages 137~143
This study has been conducted to quantify the emissions of Volatile Organic Compounds (VOCs) in a conference room. The carpet has emitted a variety of VOCs, but in this study, 2 VOCs compounds have been considered: Ethylbenzene and 1, 2, 3-Trimethylbenzene. In this study, a three dimensional numerical analysis has been carried out to investigate the emission and behavior characteristics of Ethylbenzene and 1, 2, 3-Trimethylbenzene emitted from the carpet in the conference room. The mass diffusion coefficient and the initial concentrations of VOCs in the carpet have been obtained from experimental data with non-linear regression. It has been found that the concentrations and emission factors of VOCs have exponentially decayed with time and that the concentration gradients and emission factors of VOCs are different from each other for various components. This study may supply fundamental understandings for the emission and behavior characteristics of VOCs.
The Possibility on Utilization of Underground Pit for Reduction of Cooling and Heating Load
Cho Sung-Woo ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 18, issue 2, 2006, Pages 144~150
The purpose of this study is to predict outlet temperature and humidity through underground pit for the reduction of cooling load and heating load. Commonly, the underground temperature is lower than outdoor in summer but the reverse happens in winter. When the outdoor average air temperature is
during cooling periods, the average outlet air temperature through underground pit is
with 3 m-depth and 60m-length and is
with 3 m-depth and 150 m-length. When the outdoor average air temperature is
during heating periods, the average outlet air temperature through underground pit is
with 3m-depth and 60 m-length and is
with 3 m-depth and 150 m-length. The outlet air temperature is affected by more length than depth of underground pit. The diffusion ratio of outdoor humidity is
in cooling periods and
in heating periods.
Performance Evaluation of Finned Tube Heat Exchanger with Vortex Generators in a Low Reynolds Number Regime
Kwak Kyung-Min ; Song Gil-Dal ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 18, issue 2, 2006, Pages 151~157
The present paper reports the method for evaluation of heat-transfer performance of finned tube heat exchangers in a low Reynolds number regime (Re =
) and also reports the data of heat transfer and pressure loss taken from a finned tube heat exchanger with/without vortex generators (VGs) installed as a heat-transfer enhancement device. The evaluation is based on the modified single blow method conducted in a specially designed low Reynolds number duct. Three different test core geometries, i.e., fin only, fin-tube without VGs and that with VGs, are studied here. The data of heat transfer and pressure loss taken from the fin only geometry agree well with the empirical correlations, thus validating the present method as used for low Reynolds number regime. The data taken from the finned tube geometries with and without VGs are presented and compared to examine the effect of VGs in the low Reynolds number regime.
Effect of the Exhaust Heat from Micro Gas Turbine on the Performance Characteristics of the Absorption Chiller
Choi Kyoung-Shik ; Sohn Wha-Seung ; Kim HyoungSik ; Rhim Sang-Kyu ; Hur Kwang-Beom ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 18, issue 2, 2006, Pages 158~162
Micro gas turbine (MGT) has received attention recently as a small-scale distributed power source. Due to many advantages such as their small size, low maintenance cost and minimal vibrations during operation, they are expected to become widespread in a wide range of applications. The exhaust heat emitted by the MGT is in the form of an exhaust gas that is about
which is an extremely clean gas. Korea Gas Corporation (KOGAS) has researched performance characteristics of a cogeneration system combining 28kW class MGT and 13 USRT class absorption hot and chilled water generator in the local condition. The present results of this study can be summarized as follows: (1) in heating mode, the total efficiency of cogen. system is about
and heating capacity is 33kW at 25kW MGP power (2) in cooling mode, COP is about 0.6 at 22kW MGT power.
Fuzzy Control Algorithms for the Compressor and the Electronic Expansion Valve of a Multi-type Air-conditioning System using Multiple Input Variables
Han, Do-Young ; Park, Kwan-Jun ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 18, issue 2, 2006, Pages 163~171
In order to control multi-zone temperatures, a multi-type air-conditioning system may be used. In this study, control algorithms for the compressor and the electronic expansion valve of a multi-type air-conditioning system were developed by using fuzzy logics. The compressor control algorithm was composed of a compressor pressure setpoint algorithm, a compressor pressure setpoint reset algorithm, and a compressor frequency setpoint algorithm. The electronic expansion valve control algorithm was composed of an indoor temperature control algorithm, and a superheat control algorithm. These algorithms were applied to a multi-type air-conditioning system. Test showed good results for the control of a multi-type air-conditioning system.
Program Development for Detecting Charged Refrigerant Amount in System Air-Conditioner using Fuzzy Algorithm
Tae S. J. ; Choi C. S. ; Kim H. M. ; Cho K. ; Moon J. M. ; Kim J. Y. ; Kwon H. J. ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 18, issue 2, 2006, Pages 172~179
This study developed a program for detecting charged refrigerant amount in system air-conditioner. System air-conditioner is an air-conditioning system with multiple indoor units. Due to the complexity of the system, it is more difficult to detect the refrigerant amount charged in the system air-conditioner than in a general single air-conditioner. Experiments were performed for a 6 HP outdoor unit with 3 indoor units in a psychrometric calorimeter. The experimental amount of the charged refrigerant was ranged from
increasement. Fuzzy algorithm was employed for detecting the charged refrigerant amount in the system air-conditioner. The experimental data were used for curve-fitting for the general ranges of indoor and outdoor temperature conditions. Membership function was determined for the whole ranges of experimentally measured data and rule-bases were defined for each charged refrigerant amount. Developed program successfully predicted the measured data within
Air Distribution Performance According to the Gap Opening of a Temperature Controlled Diffuser
Han Hwataik ; Shin Min-Woo ; Yom Chol-Min ; Choi Sun-Ho ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 18, issue 2, 2006, Pages 180~185
This study has been conducted in order to develop a temperature-controlled round pan diffuser with variable-openings. Flow visualization was performed to investigate the airflow patterns according to gap openings. The velocity profiles were measured using an omni-directional anemometer for two cases, i.e. a horizontal and a vertical discharge conditions. Numerical simulation also confirms there is a narrow range of gap openings where a horizontal discharge shifts to a vertical discharge. The air distribution performance index increases abruptly when the air discharge shifts from vertical to horizontal direction.
A Study on the Optimal Orifice Location for Air flow Measurement in an Air Duct Leakage Tester
Lee Seung-Chul ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 18, issue 2, 2006, Pages 186~191
In this study, five experiments were carried out, with an orifice located downstream of a fan in case I where upstream duct length is 6 D, and that in the downstream is 4 D and different downstream distance to the fan in the rest, so as to determine the optimal location of the orifice and reduce the duct length of airflow measurement device. The resulting flow rate-pressure drop correlations were found to satisfy the limitation of SMACNA standard, which specified an error of
based on the real flow rate. Also, the best one of five. cases was achieved with the orifice located midway of the orifice duct four times its diameter long.