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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 19, Issue 12 - Dec 2007
Volume 19, Issue 11 - Nov 2007
Volume 19, Issue 10 - Oct 2007
Volume 19, Issue 9 - Sep 2007
Volume 19, Issue 8 - Aug 2007
Volume 19, Issue 7 - Jul 2007
Volume 19, Issue 6 - Jun 2007
Volume 19, Issue 5 - May 2007
Volume 19, Issue 4 - Apr 2007
Volume 19, Issue 3 - Mar 2007
Volume 19, Issue 2 - Feb 2007
Volume 19, Issue 1 - Jan 2007
Selecting the target year
Thermal Load Simulation Analysis on Model Building Estimating Optimum Heat Source Capacity
Park, Jong-Il ; Kim, Se-Hwan ; Lee, Sung ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 19, issue 6, 2007, Pages 427~433
Generally, H.V.A.C load capacity in early planning phase can presume with maximum thermal load. Basic data can prove by air conditioning equipment system data analysis at existing building. There are poor and not reliable alternative presentation. In this paper, measured data after use H.V.A.C load calculation K-load program reply choosing standard building and variables simulation. And I founded peak load correlation graph and mode for several kinds of variable and contents of size. I wish that equipment designer is beaconed to produce optimum capacity at building as quantitative through this result.
Numerical Analysis of the Melting Process of Ice Using Plate Heaters with Constant Heat Flux
Kim, Hark-Koo ; Jeong, Si-Young ; Hur, Nahm-Keon ; Lim, Tae-Won ; Park, Yong-Sun ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 19, issue 6, 2007, Pages 434~440
One of the cold start problems of a FCV is the freezing of the water in the water tank when a FCV is not in operation and the surrounding temperature drops below
. The ice in the tank should be melted as quickly as possible for a satisfactory operation of fuel cell vehicles. In this study, the melting process for the constant heat fluxes of the plate heaters was numerically calculated in the 2-D model of the tank and plate heaters. The enthalpy method and FVM code was used for this analysis. The changes of the temperature with heat fluxes and the heat transfer area could be investigated. The energy balance error was found to increase with the heat flux. From this numerical analysis, the proper heat flux value and some important design factors relating local overheating and pressurization of the water tank could be examined.
Air-water Countercurrent Flow Limitation in Narrow Rectangular Channels
Kim, Byong-Joo ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 19, issue 6, 2007, Pages 441~446
An experimental study on the countercurrent two-phase flow in narrow rectangular channels has been peformed. Countercurrent flow limitation (CCFL) was investigated using air and water in 760mm long, 100mm wide, vertical test sections with 1 and 3mm channel gaps. Tests were systematically performed with downward liquid superficial velocities and upward gas velocities covering 0 to 0.125 and 0 to 3.5m/s ranges, respectively. As the gap width of rectangular channel increased the CCFL water superficial velocity decreased for the given air superficial velocity. Slight increase of the air superficial velocity resulted in the abrupt decrease of water velocity when
. The critical superficial velocity of air, at which the downward flow of water was no longer allowed, also decreased with the increase of gap width. The experimental results were compared with the previous correlations, which were mainly for round tubes, and the qualitative trends were found to be partially acceptable. However the quantitative discrepancies were hardly neglected. New correlation of CCFL was developed and showed good agreement with the experimental data.
Analysis of Particles Motion in Vertical Rayleigh Flow
Ko, Seok-Bo ; Jun, Yong-Du ; Lee, Kum-Bae ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 19, issue 6, 2007, Pages 447~456
Suspended particles behavior when they go through a vertical riser with heat transfer is of significant concern to system designers and operators in pneumatic transport, various processes such as in chemical, pharmaceutical and food industries. When it comes with the energy system, that knowledge is critical to the reliable design practices of related equipment as heat exchangers, especially in the phase of system scale-up. Without haying a good understanding of the related physics, many scale-up practices based on their pilot plant experience suffer from unexpected behaviors and problems of unstable fluidization typically associated with excessive pressure drop, pressure fluctuation and even unsuccessful particle circulation. In the present study, we try to explain the observed phenomena with related physics, which may help understanding of our unanswered experiences and to provide the designers with more reliable resources for their work. We selected hot exhaust gas with solid particle that goes through a heat exchanger riser as our model to be considered. The effect of temperature change on the gas velocity, thermodynamic properties, and eventually on the particles motion behavior is reviewed along with some heat transfer analyses. The present study presents an optimal riser length at full scale under given conditions, and also defines the theoretical limiting length of the riser. The field data from the numerical analysis was validated against our experimental results.
Comparison of Correlations of Saturated Vapor Density for Some Refrigerants
Park, Kyoung-Kuhn ; Kang, Byung-Ha ; Jang, Si-Youl ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 19, issue 6, 2007, Pages 457~463
Various correlations of saturated vapor density in a truncated power series form are tested and compared in this study. Saturated vapor density correlation can be expressed relating logarithmic reduced density to the reduced temperature. Five types of correlation has been investigated using saturated vapor density data for 22 pure substance refrigerants from ASHRAE (American Society of Heating, Reftigerating and Air-Conditioning Engineers, Inc.) property tables and NIST (National Institute of Standards and Technology) Chemistry Webbook. Correlations are fitted to the data points by least squares method. Data points are equally weighted. The best type of correlation among the five types is suggested. The results obtained indicate that the best correlations with 3, 4, and 5 terms yield average AAD's (Average Absolute Deviation) of 0.27%, 0.04%, and 0.02%, respectively, while widely used conventional correlations with 3, 4, and 5 terms yield those of 1.19%, 0.61%, and 0.17%. The suggested type of correlation could reduce the number of terms while improving performance.
A Case Study on Green Remodeling of Water System in Jeju Airport
Kim, Byung-Hyun ; Na, Su-Yeun ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 19, issue 6, 2007, Pages 464~469
The case study aims to propose the green remodeling strategies of water system in Jeju international airport facilities considering the environmental conditions of Jeju Island. The rain water was proposed as an alternative water source to conserve of under ground water resources. Computations of daily precipitation, rain collection, runoff and water usage was conducted to investigated the feasibility of the rain water system design.
Economic Analysis of Heat Pump System through Actual Operation
Kim, Gil-Tae ; Cheong, Seong-Ir ; Joo, Ho-Young ; Ahn, Young-Chull ; Lee, Jae-Keun ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 19, issue 6, 2007, Pages 470~475
The present study has been conducted economic analysis through actual operation of electric heat pump (EHP) and gas engine driven heat pump (GHP) which are installed at the same building in the university. Cost items, such as initial cost, annual energy cost and maintenance cost of each system are considered to analyze life cycle cost (LCC) and economical efficiencies are compared. The initial cost is considered on the basis of actual cost, and annual energy cost is converted into the cost after measuring electricity and gas consumption a day LCC applied present value method is used to assess economical profit of both of them. Variables used to LCC analysis are electricity cost escalation rate, natural gas cost escalation rate, interest rate, and service lives when each of them are 4%, 2%, 8%, and 20 years. The result shows that EHP (148,257,306 won) is more profitable than GHP (161,239,296 won) by 8.05% (12,981,990 won).
A Study on the Prediction of Building Equipment Noise Generates at Machine Room
You, Hee-Jong ; Jung, Eun-Jung ; Kim, Jae-Soo ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 19, issue 6, 2007, Pages 476~484
Recently, in accordance with the buildings are becoming to large-sizes, high-stories, the large scaled facilities and equipments in machine room are quite demanding, and the generated noise volume according to this situation is on increasing. Since such noise is becoming to the object of a serious civil appeal, it is the real situation that a reduction countermeasure against the machine room equipment noise is keenly necessitated. On such viewpoint, this study has recorded, measured the noises which were generated from each individual as same as the whole equipped machines and tools, on the object of the dormitory machine rooms of the 3 colleges that haying mutually different peculiarities, then after grasp-ing their characters and acoustic powers, this research has verified its prediction possibility and the authenticity by comparison the estimated numerical value with the actually measured numerical value through the acoustic simulation. After grasping the prediction possibility in such way, by utilization of the sound absorption material in the machinery room, from the stage of design, the soundproof measures for the noise reduction at machine room could be regulated effectively, and it is also considered that such data would be utilized as the fundamental material for an establishment of the measure for sound insulation.