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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 15, Issue 12 - Dec 2003
Volume 15, Issue 11 - Nov 2003
Volume 15, Issue 10 - Oct 2003
Volume 15, Issue 9 - Sep 2003
Volume 15, Issue 8 - Aug 2003
Volume 15, Issue 7 - Jul 2003
Volume 15, Issue 6 - Jun 2003
Volume 15, Issue 5 - May 2003
Volume 15, Issue 4 - Apr 2003
Volume 15, Issue 3 - Mar 2003
Volume 15, Issue 2 - Feb 2003
Volume 15, Issue 1 - Jan 2003
Selecting the target year
Effects of the Mass of Working Fluid on the Thermal Performance of Heat Pipe with Axial Grooves
Suh, Jeong-Se ; Park, Young-Jun ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 1, 2003, Pages 1~8
An analytical and experimental study of the thermal performance of axial heat pipe with axial groove is conducted to determine the optimal mass of working fluid for the maximum heat transport capacity of heat pipe with axial grooves. Generally, the mass of working fluid has been fully charged by considering only a geometrical shape of axial grooves embedded in a heat pipe. When the heat pipe is operated in a steady state, the meniscus re-cession phenomena of working fluid is occurred in the evaporator region. In this work, the optimal mass of working fluid was obtained from the axial variation of capillary pressure, the radius of curvature and wetting angle of meniscus of liquid-vapor interface. Experimental results were also obtained by varying the mass of working fluid within a heat pipe, and presented for the maximum heat transport capacity corresponding to the operating temperature and the elevation of heat pipe. Finally, the analytical results of the optimal mass of working fluid were compared with those of the experimental mass of working fluid.
Experimental Study on Measuring the Intermittency in the Transitional Boundary Layer
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 1, 2003, Pages 9~18
An experimental study was performed to investigate the turbulence intermittency measuring methods across the boundary layer in the transition region. A single type hot-wire probe was used to measure instantaneous streamwise velocities in laminar, transitional and turbulent boundary layer To estimate wall shear stresses on the flat plate, near wall mean velocities are applied to the principle of CPM. Distribution of intermittency factor is obtained by dual-slope method and compared to the results of four methods,
, TERA and M-TERA method. In these methods, M-TERA shows a good agreement in the near wall region. However, the result of M-TERA method shows that intermittency factor is underestimated in the outer part and outside of the boundary layer and the dimensional constant of M-TERA method should be changed appropriately depending on measuring point.
Experimental Correlation of Wettability for Micro-scale Hatched Tubes
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 1, 2003, Pages 19~24
The objectives of this paper are to develop a new method of wettability mea-surement and to study the effect of surface roughness on the wettability in a
/LiBr falling film absorber. Two absorber tubes with micro-scale roughness and a bare tube are tested in a falling film absorber installed in a test rig. Inlet solution temperature, concentration and mass flow rate are considered as key parameters. A new method is proposed to estimate the wettability of a tube by measuring a minimum mass flow rate to wet the tube completely. The wettability for the structured surfaces was higher than that for the bare tube. The wettability decreased linearly along the vertical location. The wettability increased with increasing the solution temperature and the solution mass flow rate. The experimental correlations of the wettability for the bare and the micro-hatched tubes were developed with error bands of
, respectively. This work can be used in the design of absorbers with micro-scale roughness.
Design of Oil Supply Enhancement Device for a Variable Speed Reciprocating Compressor
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 1, 2003, Pages 25~31
This paper addresses an oil supply enhancement device to resolve a shortage of oil supply or no oil supply at all encountered at low speed operation for a variable speed reciprocating compressor used for household refrigerators. The oil supply enhancement device comprises a moving cylinder attached to the lower end of crankshaft and two of fluid diodes, each one at the inlet and outlet of the cylinder. Up-and-down movement of the cylinder against the lower end of the crankshaft together with the functioning of the two fluid diodes produces net oil flow from oil reservoir to inside the crankshaft. The experiment on the test bench has shown that enough oil supply into the oil feeding hole cu be made by using this device even at low speed range. Some analytical study has also been carried out to under-stand its oil supply mechanism.
Analysis on Thermal Environment in the Rotunda of New National Museum of Korea
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 1, 2003, Pages 32~39
Thermal comfort in the Rotunda which is high wide visiting space of the new national museum of Korea has been numerically investigated in this paper. To evaluate thor-mal comfort of the Rotunda, well-known indices, PMV and PPD were introduced. The results of present investigation show that thermal comfort is satisfied at the breathing zone of the visiting space. However a thermal stratification with
of temperature difference occurs along the height of the Rotunda which makes the thermal environment worse. For example, the PPD value reaches up to 50% in the 6th floor connection passage. Consequently, additional HVAC design factors should be considered in order to reduce the large thermal stratification.
Emission Characteristics of Volatile Organic Compounds (VOCs) from a Carpet
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 1, 2003, Pages 40~49
This study has been conducted to identify and quantify the emissions of Volatile Organic Compounds (VOCs) from a new carpet. The carpet sample consists of polypropylene cushion and latex backing. The VOCs have been sampled on sorbent tubes and analyzed by thermal desorption unit and GC/MSD. For over 240 hours, concentration of VOCs has been measured in a small chamber made of stainless steel. With the measured data, emission factor and mass balance have been considered. The experiments have been conducted in accordance with ASTM D5116-97. The carpet has emitted a variety of VOCs, but in this study, 7 VOCs compounds have been considered： chlorobenzene, ethylbenzene, styrene, isopropylbenzene, bromobenzene, 2-chlorotoluene, and 1,2,3-trimethylbenzene. The results show that the concentrations of VOCs and the emission factors have exponentially decayed from relatively high level to low level with time. The gradients of the concentration of VOCs and emission factors are different for various components. It is found that styrene, 2-chlorotoluene are emitted more than others with higher concentrations.
CFD Simulation on the Oil Pumping System of a Variable Speed Scroll Compressor with a Swing Pump
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 1, 2003, Pages 50~58
An analytical study was carried out to investigate the performance of an oil pumping system of a variable speed compressor using a commercial CFD program. The simulations for the oil supplying system with the oil and air mixture were performed by varying compressor speed from 40 Hz to 90 Hz. Comparing the predicted with the measured data on the modified scroll compressor validated the simulation model. The predicted results were consistent with the test data with a maximum deviation of 12.8%. The oil flow rate significantly increased with a rise of compressor speed due to a higher oil flow rate from the swing pump and a greater centrifugal force on oil gallery.
Simulation for High Efficient Heat Pump System using Seawater Heat Source and Exhaust Energy
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 1, 2003, Pages 59~66
The purpose of this study is to analyze the characteristics (COP) of the heat pump system for various operating conditions with the use of seawater heat source and exhaust energy. To accomplish the goal, first of all, the computer simulation for heat pump system is carried out. The heat pump system model is made of a waste heat recovery system and a vapor compression refrigeration system, and the working fluid is R-22. The model calculated the change of COP with the variation of temperature and flow rate. The COP and the plate heat exchanger (PHE) area of the heat pump system are considered moderately high in the condensation temperature of
and the evaporation temperature of
in indoor culture system. The simulation results will be used effectively for the design and the performance prediction of heat pump system using unused energy in a land base aquaculture system.
A Study on the Laws of Building Service System Construction
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 1, 2003, Pages 67~72
The aim of this paper is to investigate the laws of building service system among the laws of construction and to show alternative proposals against the problems. The result of this paper is to simplify the construction laws which will reduce construction administration complexity and to increase productivity of construction works. Among the construction laws, we must revise mechanical engineers' role because of increasing mechanical system's importance than before. Through this study the author will show the improvement of building service system technology and the quality of construction industry.
Data Reduction on the Air-side Heat Transfer Coefficients of Heat Exchangers under Dehumidifying Conditions
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 1, 2003, Pages 73~85
Four different methods of reducing the heat transfer coefficients from experimental data under dehumidifying conditions are compared. The four methods consist of two different heat and mass transfer models and two different fin efficiency models. Data are obtained from two heat exchanger samples having plain fins or wave fins. Comparison of the data with the reduction methods revealed that the single potential heat and mass transfer model yielded the humidity independent heat transfer coefficients. Two different fin efficiency models - enthalpy model and humidity model - yielded approximately the same fin efficiencies and accordingly approximately the same heat transfer coefficients. The heat transfer coefficients under wet conditions were approximately the same as those of the dry conditions for the plain fin configuration. For the wave fin configuration, however, wet surface heat transfer coefficients were approximately 12% higher. The pressure drops of the wet surface were 10% to 45% larger than those of the dry surface.