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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 24, Issue 12 - Dec 2012
Volume 24, Issue 11 - Nov 2012
Volume 24, Issue 10 - Oct 2012
Volume 24, Issue 9 - Sep 2012
Volume 24, Issue 8 - Aug 2012
Volume 24, Issue 7 - Jul 2012
Volume 24, Issue 6 - Jun 2012
Volume 24, Issue 5 - May 2012
Volume 24, Issue 4 - Apr 2012
Volume 24, Issue 3 - Mar 2012
Volume 24, Issue 2 - Feb 2012
Volume 24, Issue 1 - Jan 2012
Selecting the target year
Comparison of System Performances of Hot-gas Bypass and Compressor Variable Speed Control of Water Coolers for Machine Tools
Jeong, Seok-Kwon ; Lee, Dan-Bi ; Yoon, Jung-In ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 24, issue 1, 2012, Pages 1~8
DOI : 10.6110/KJACR.2012.24.1.001
Recently, the needs of system performances such as working speed and processing accuracy in machine tools have been increased. Especially, the speed increment generates harmful heat at both moving part of the machine tools and handicrafts. The heat is a main drawback to progress accuracy of the processing. Hence, a cooler system to control temperature is inevitable for the machine tools. In general, two representative control schemes, hot-gas bypass and variable speed control of a compressor, have been adopted in the water cooler system. In this paper, comparisons of system performances according to the control schemes in a cooler for machine tools were conducted in detail. Each proportional-integral feedback controller for the two different control systems is designed. The system performances, especially the temperature control accuracy and coefficient of performance which is a criterion of energy saving, were mainly analyzed through various experiments using 1RT water cooler system with different two types of control scheme. These evaluations will provide useful information to choose suitable water cooler system for the engineers who design controllers of the cooler system for machine tools.
Development of a Simple Analytical Model for Desiccant Wheels-II. Effectiveness Correlations
Kim, Dong-Seon ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 24, issue 1, 2012, Pages 9~15
DOI : 10.6110/KJACR.2012.24.1.009
An effectiveness model has been developed from the approximate analytical solution of a rotary desiccant wheel. The resulting equations clearly show that the maximum air temperature and humidity differences are two independent driving forces commonly acting in the heat and mass transfer processes. Comparison with the numerical model from the preceeding study revealed that the effectiveness model could make realistic predictions roughly with 10% uncertainty. The model may be useful for the rough design and analysis of desiccant evaporative cooling systems.
Heat and Mass Transfer Characteristics of LiCl Aqueous Solution for a Plate Heat Exchanger Type Dehumidifier
Jeon, Dong-Soon ; Lee, Hae-Seung ; Kim, Seon-Chang ; Kim, Young-Lyoul ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 24, issue 1, 2012, Pages 16~22
DOI : 10.6110/KJACR.2012.24.1.016
Experimental investigations were carried out to examine the heat and mass transfer characteristics of LiCl aqueous solution for a plate heat exchanger type dehumidifier. Cooling dehumidification was adopted vertical type heat exchanger. Also non woven fabric is attached surface of the heat exchanger for spreadability of LiCl aqueous solution. Mass flow-rate of LiCl aqueous solution and concentration were selected as experimental conditions. Also, In this study, the effects of relative humidity of process air and velocity were investigated experimentally. As a result of heat transfer coefficient and mass transfer coefficient of were increased film reynolds number increased. heat transfer coefficient and mass transfer coefficient of LiCl aqueous solution were 0.14~0.24 kW/
Aerodynamic Analysis of Automotive HVAC Duct for Enhancement of Cooling/Heating Performance
Ju, Jae-Woo ; Lee, Ki-Don ; Heo, Man-Woong ; Kim, Kwang-Yong ; Park, June-Kyu ; Yun, Jung-Hwan ; Kim, Hong-Bin ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 24, issue 1, 2012, Pages 23~28
DOI : 10.6110/KJACR.2012.24.1.023
In the present work, numerical analyses of air flow in HVAC duct have been carried out for enhancement of cooling/heating performance. For the analyses, three-dimensional Reynolds-averaged Navier-Stokes equations have been solved with the shear stress transport turbulence model. The numerical results were validated in comparison with the experimental data. Based on the numerical results, the HVAC duct was designed to reduce the pressure loss. The modified duct geometry shows largely reduced pressure drop in comparison with the reference geometry. And, through modified duct shape, the performance of air conditioning has been enhanced.
An Experimental Study on the Dehumidification Characteristics and the Effectiveness for Operating Conditions of a Desiccant Rotor
Kang, Byung-Ha ; Lee, Jin-Joo ; Kim, Suk-Hyun ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 24, issue 1, 2012, Pages 29~36
DOI : 10.6110/KJACR.2012.24.1.029
An experimental study has been carried out to investigate the dehumidification characteristics for several operating conditions of a compact desiccant rotor. This problem is of particular interest in the design of a desiccant type of dehumidifier. Room temperature, room humidity, regeneration temperature, revolution speed and frontal air velocity of desiccant rotor are varied as operating conditions. The results obtained indicate that dehumidification rate is increased with an increase in the room humidity while dehumidification effectiveness is not changed much. It is also found that the optimal rotor speed and optimal regeneration temperature exist for maximum dehumidification rate and dehumidification effectiveness.
Computational Study of Energy Loss in a Pipe of Refuse Collecting System
Lee, Jong-Gil ; Byun, Jae-Ki ; Choi, Young-Don ; Choi, Yoon ; Hong, Ki-Chul ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 24, issue 1, 2012, Pages 37~44
DOI : 10.6110/KJACR.2012.24.1.037
This paper describes energy loss in a pipe line of refuse collecting system. Analysis of energy loss in a pipe line is the decisive factor in a design of refuse collecting system. Using the results of energy loss analysis, we can determine the power of turbo-blower. The flow characteristics of the pipe line with refuse bags were analyzed by three-dimensional CFD. The refuse bag is modeled by using the shape obtained from profile measurement. Friction factors were calculated with changing the refuse bag size, mixing ratio and Reynolds number. And drag coefficients were calculated using the CFD results. From the results we can calculate energy loss in a pipe line of refuse collecting system and predict the capacity of turbo-blower.
Effect of Expansion Ratio on Contact Heat Transfer Coefficient in Fin-Tube Heat Exchanger
Lee, Sang-Mu ; Park, Byung-Duck ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 24, issue 1, 2012, Pages 45~50
DOI : 10.6110/KJACR.2012.24.1.045
The plate fin and tube type of heat exchanger is widely used in air conditioner, and the heat exchanger is assembled by the mechanical expansion of copper tubes and fastening the aluminum fin. The objective of the present study is to investigate how the mechanical expansion of copper tube affects on the heat transfer performance of a plate fin and tube type heat exchanger. This study has been performed by experimental and numerical methods. The numerical and experimental results show that the tube expansion ratio has a influence on the heat transfer performance. Within the tested expansion ratio, the contact pressure shows the peak value and it decreases as the expansion ratio increases. Air-side heat transfer coefficient increases until the expansion ratio reaches 1.23, and then decreases with the similar pattern to the contact pressure. Also, contact heat transfer coefficient shows the maximum when the contact pressure is highest as well as the air-side heat transfer coefficient.
Optimization Study on the Performance Analysis of Organic Rankine Cycle for Characteristics of Low Temperature Heat Sources
Eom, Hong-Sun ; Yoon, Cheon-Seog ; Kim, Young-Min ; Shin, Dong-Gil ; Kim, Chang-Gi ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 24, issue 1, 2012, Pages 51~60
DOI : 10.6110/KJACR.2012.24.1.051
Optimization procedures of performance analysis for ORC(Organic Rankine Cycle) system are established to the characteristics of low temperature heat sources such as open-type and closed-type. Effective heat recovery and heat extraction related to maximum power of the cycle as well as heat quality and thermal efficiency must be considered in the case of the open-type low temperature heat source. On the other hand, in the case of the closed-type low temperature heat source, only thermal efficiency is important due to constant heat input. In this study, thermal efficiency and exergy efficiency representing a level of close to Carnot cycle are studied, as useful index for the optimization of the ORC system. To validate the results of cycle analysis, those are compared with appropriate experimental data of ORC system as a thermal efficiency point of view.
The Improvement of The Exterior Air Flow Environment in The Inner Curved Area of Tower Type Apartment
Chang, Hyun-Jae ; Kim, Hyung-Jin ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 24, issue 1, 2012, Pages 61~69
DOI : 10.6110/KJACR.2012.24.1.061
Recently, tower type apartment has been a main stream at the apartment market, in Korea. Tower type apartment has features that is easy to maintain a proper distance between apartment buildings, and to keep a prospect comparing to flat type apartment However, there is usually a inner curved area at tower type apartment, and it is able to make an unhealthy environment because of shaded area through a day and a bad air flow. In this study, the duration of sunshine and the exterior air flow environments are examined. As results, the duration of sunshine at the inner curved area of tower type apartment was extremely short, and the exterior air flow environment was very bad for the low air velocity of about 0.08m/s. Installing pilotis in the 1st floor which faces to the inner curved area makes the good improvement of exterior air flow environment.
The Economic Effects and Operating Characteristics of the Outdoor Unit in Accordance with Zoning Plan of Gas Engine Driven Heat Pump Installed in the University Building
Park, Kang-Hyun ; Kim, Su-Min ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 24, issue 1, 2012, Pages 70~76
DOI : 10.6110/KJACR.2012.24.1.070
The purpose of this study is to analyze of the operating characteristics of the Gas engine driven Heat Pump(GHP) and to reduce maintenance costs through the most Economical plan. As the zoning modifications that have economic effects were confirmed. Applications should be made with a similar purpose of the space. The combination of a modified space has led to reduced operating hours of the outdoor unit. The reduction of the outdoor unit operating hours, reducing maintenance costs accordingly. When analyzed at six years have elapsed, the amount of savings through zoning modifications is more than an additional construction cost. During the design phase, cost-effective operation of the GHP is required for the proper zoning plan.
Numerical Performance Analysis of the Swing Compressor
Moon, Seok-Hwan ; Noh, Ki-Youl ; Sa, Bum-Dong ; Yang, Jang-Sik ; Choi, Gyung-Min ; Kim, Duck-Jool ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 24, issue 1, 2012, Pages 77~84
DOI : 10.6110/KJACR.2012.24.1.077
Numerical performance analysis of the vane-roller integral type swing compressor was conducted. The swing compressor has been investigated for the highly efficient air conditioning system. Performance analysis results of the swing compressor were compared with those of a conventional rotary compressor. Mechanical and gas losses of a swing compressor were larger than those of a rotary compressor. However in case of mass flow rate from the discharge port, the swing compressor was about 6.68% higher than the rotary compressor. Hence the EER, the cooling capacity and the compressor work of the swing compressor were about 3.71%, 6.69% and 2.90% higher than the rotary compressor respectively.
A Study on the Application and Economical Efficiency of Electric Driven Cargo Pumping System
Cho, Dong-Ju ; Kim, Kyung-Bae ; Park, Myung-Kyu ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 24, issue 1, 2012, Pages 85~89
DOI : 10.6110/KJACR.2012.24.1.085
This study has been conducted to compare two cargo handling systems on MR tanker and Panamax tanker. Submerged hydraulic cargo pumps with hydraulic power packs and frequency converter controlled electric deepwell pumps will be investigated and compared on all aspects of initial cost, installation, operation and maintenance. The result of investigation shows Electric Systems have less manufacturing costs, higher environmental friendliness and reliable operation compare to Hydraulic Systems. Furthermore, the present experimental data will provide important database for Electric Systems onboard new ships and practical and empirical guidelines are constructed for further determine the design of the Electric Systems.