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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 of The Motion of a Circular Cylinder Suspended in a Square Enclosure
Son, Seong-Wan ; Jeong, Hea-Kown ; Ha, Man-Yeong ; Yoon, Hyun-Sik ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 11, 2010, Pages 727~734
The present study numerically investigates the motion of a solid body suspended in the square enclosure with natural convection. A two-dimensional circular cylinder levitated thermally has been simulated by using thermal lattice Boltzmann method(TLBM) with the direct-forcing immersed boundary method. To deal with the ascending, falling or levitation of a circular cylinder in natural convection, the immersed boundary method is expanded and coupled with the TLBM. The circular cylinder is located at the bottom of a square enclosure with no restriction on the motion and freely migrates due to the Boussinesq approximation which is employed for the coupling between the flow and temperature fields. For different density ratio between the cylinder and the fluid, the motion characteristics of the circular cylinder for various Grashof numbers have been carried out. The Prandtl number is fixed as 0.7.
Development and Application of a Computer Code for Prediction of Indoor Pollutant Dispersion
Jeon, Hyun-Jun ; Yang, Kyung-Soo ; Choi, Choon-Bum ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 11, 2010, Pages 735~744
An efficient code has been developed to predict dispersion of indoor air pollutants. The computing capability of the code has been compared with that of a commercial code in a benchmark test. After that, the code has been employed to compute dispersion of a pollutant released from a new furniture, a kind of Sick Building Syndrome(SBS). A sofa which generates formaldehyde is implemented by using an immersed boundary method. Large Eddy Simulation (LES) is employed to obtain time-dependent velocity and concentration fields. LES has been regarded as an academic tool, but the newly-developed code reveals a possibility of application of LES to practical problems, especially dispersion of indoor pollutants.
A Study on the Prediction of Indoor Environment in Bio Safety Level 3 Laboratory According to Biohazard Scenario
Park, Hyun-Jin ; Hong, Jin-Kwan ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 11, 2010, Pages 745~750
Since the implementation of the LMO Law in Korea, the importance of the design qualification of BSL3 lab. is emphasizing. In this study, multizone simulation for three kind of biohazard scenarios using CONTAM is performed for design qualification of BSL3 lab. Also, in the case of unexpected spread of contaminants such as Influenza A virus(H1N1) in BL3 zone, the design qualification is carried out for diffusion and decontamination of contaminants according to differential pressure of BSL3 anteroom and door area of BSL3 lab. Also, in this study, appropriateness of laboratory room differential pressure and air flow rate to maintain pressure difference between laboratory rooms, and energy consumption due to air change rate variation according to door area in BL3 lab. Simulation results show that these approach methods are used as a tool for the design and verification of BL3 lab.
A Study on the Pressure Loss Characteristics of Micro-Channel PCHE
Kim, Jin-Hyuck ; Baek, Seung-Whan ; Jeong, Sang-Kwon ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 11, 2010, Pages 751~759
A newly developed type PCHE(Printed Circuit Heat Exchanger), which has a longitudinal corrugation flow channel, was fabricated using etching and diffusion bonding to evaluate its hydraulic performance. The pressure drop characteristics obtained from the experimental results are presented and the local friction factors associated with different hydraulic diameters and inclination angles are discussed. The results of a three-dimensional numerical simulation are presented, conducted using commercial CFD(Computational Fluid Dynamics) software at lower Reynolds number range. The numerical results were validated by experimental data obtained from helium gas experimental apparatus. The results of CFD prediction show fairly good agreement with the experimental data.
An Experimental Study on Semiconductor Process Chiller for Dual Channel
Cha, Dong-An ; Kwon, Oh-Kyung ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 11, 2010, Pages 760~766
Excessive heat occurs during semiconductor manufacturing process. Thus, precise control of temperature is required to maintain constant chamber-temperature and also wafer-temperature in the chamber. Compared to an industrial chiller, semiconductor chiller's power consumption is very high due to its continuous operation for a year. Considering the high power consumption, it is necessary to develop an energy efficient chiller by optimizing operation control. Therefore, in this study, a semiconductor chiller is experimentally investigated to suggest energy-saving direction by conducting load change, temperature rise and fall and control precision experiments. The experimental study shows the cooling capacity of dual-channel chiller rises over 30% comparing to the conventional chiller. The time and power consumption in the temperature rising experiment are 43 minutes and 8.4 kWh, respectively. The control precision is the same as
in any cases. However, it appears that the dual channel's control precision improves to
when the setting temperature is over
Numerical Study of Flow Around an Oscillating Sphere
Lee, Jin-Woog ; Lee, Dae-Sung ; Ha, Man-Yeong ; Yoon, Hyun-Sik ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 11, 2010, Pages 767~772
The incompressible viscous flow past a sphere under forced oscillation is numerically investigated at a Reynolds number of 300. The immersed boundary method is used to handle the sphere oscillating vertically to the streamwise direction. There are two important variables to characterize the oscillating state of a sphere. One is an oscillating amplitude normalized by the sphere diameter is set as a fixed number of 0.2. Another is the frequency ratio which is defined by
, where fe and fo are the excited frequency and the natural frequency of vortex shedding for the stationary sphere. In this study, three different frequency ratios of 0.8, 1.0 and 1.2 are considered. The results show a periodic flow with hairpin vortices shedding from upper and lower positions as well as vortical legs obliquely extended by oscillating motion of sphere. The enveloping vortical structure experience rupture twice in one period of oscillation. As the frequency of oscillation is increased, the vortical legs are getting shorter and eventually the hairpin vortices are much closer to the adjacent one.
A Study for Characteristics of Stack Plume Dispersion under Various
Park, Il-Seouk ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 11, 2010, Pages 773~780
The dispersion of plume which is emitted from a chimney is governed by a lot of factors： wind, local terrain, turbulence intensity of atmosphere, and temperature, etc. In this study, we numerically investigate the plume dispersions for various altitudinal temperature gradients and wind speeds. The normal atmosphere has the temperature decrease of
, however, actually the real atmosphere has the various altitudinal temperature profiles according to the meteorological factors. A previous study focused on this atmospheric temperature gradient which induces a large scale vertical flow motion in the atmosphere thus makes a peculiar plume dispersion characteristics. In this paper, the effects of the atmospheric temperature gradient as well as the wind speed are investigated concurrently. The results for the developing processes in the atmosphere and the affluent's concentrations at the ambient and ground level are compared under the various altitudinal temperature gradients and wind speeds.
A Study on the Working Pressure of TBP Used in High Pressure
Lee, Sung-Ho ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 11, 2010, Pages 781~787
To improve the efficiency of piping, recently the pre-fabrication piping system has been introduced, and much attention has been paid to TBPs which can replace Tee-joint. Forming and forming analysis on TBPs made from Carbon steel pipes for pressure service(KS D 3562 Sch40) and Stainless steel pipes(KS D 3576 20S) have been conducted to determine working pressure. Forming and forming analysis objects are
Analyses on Photosensor Illuminance for Prediction of Fluctuating Illuminance by Daylight Dimming Control Systems
Kim, Soo-Young ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 11, 2010, Pages 788~797
This study examines the influence of fluctuating daylight illuminance on daylight dimming control systems. Field measurements were performed for a full-scale mocked-up model under various daylight conditions in winter. Fluctuating ranges for a partially-shielded photosensor were great when the variation of sky ratio was great. When solar altitude was lower the illuminance and fluctuating range of illuminance were great due to the influence of direct components of daylight and the interrefelction between surfaces in rear area of space. It implies that daylight dimming system would not function effectively, unless the desktop illuminance by daylight is enough. Fluctuation ranges of photosensor illuminance were lower than 50 lx under clear sky conditions, but they were greater than 100 lx under partly-cloudy sky conditions. It means that the fluctuation range of electric light output of lighting fixture would greater under the partly-cloudy conditions and cause potential visual annoyance to occupants. Outdoor vertical illuminance reaching the windows would be an effective factor that can be used to predict the fluctuation of photosensor signals for effective controls of daylight dimming system.
A Study on Prediction of Hourly Cooling Load Using Building Area
Yoo, Seong-Yeon ; Han, Kyu-Hyun ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 11, 2010, Pages 798~804
New methodology is proposed to predict the hourly cooling load of the next day using maximum/minimum temperature and building area. The maximum and minimum temperature are obtained from forecasted weather data. The cooling load parameters related to building area are set through a database provided from reference buildings. To validate the performance of the proposed method, the predicted cooling loads in hourly bases are calculated and compared with the measured data. The predicted results show fairly good agreement with the measured data for benchmarking building.
Analysis of Thermal Performance of Solar Hot-Water and Heating System with Baffle Storage Tank
Suh, Jeong-Se ; Yi, Chung-Seub ; Yoon, Ji-Hoon ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 11, 2010, Pages 805~811
A numerical study has been performed to investigate the thermal performance of solar heating system with baffle type of storage tank by using the commercial code TRNSYS. As a result, the solar fraction depends strongly on the efficiency and heat loss coefficient of solar collector as well as the heating capacity of house and the water temperature supplied to the shower. In addition, the solar fraction has been basically ranked to higher level in baffle type of storage tank than typical type of single storage tank for the range of operation condition.
Study on Evaluation Analysis on Thermal Performance of Window Using A. S. Lab.(Artificial Solar Laboratory)
Kang, Ki-Nam ; Lee, Keon-Ho ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 11, 2010, Pages 812~819
Recently residential buildings are characterized with high-rise and high density. Under this circumstance, achieving comfortable and healthy indoor environment with minimized energy consumption becomes a very challenging engineering and societal issue. Along this the increased size and transparency of window as well as light surface caused by high stories lowers the heat shield efficiency of building. Since glass that constitutes building surface has low heat efficiency, it aggravates heat loss of all building considerably, thereby resulting in extreme heating load and cooling load in the country where temperature varies much in summer and winter. The research will check whether experiment can be effectively done by overcoming the limit of existing artificial solar laboratory constructed in the country and properly adjusting controlled variables with simplified function through construction of this experimental set.