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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 20, Issue 12 - Dec 2008
Volume 20, Issue 11 - Nov 2008
Volume 20, Issue 10 - Oct 2008
Volume 20, Issue 9 - Sep 2008
Volume 20, Issue 8 - Aug 2008
Volume 20, Issue 7 - Jul 2008
Volume 20, Issue 6 - Jun 2008
Volume 20, Issue 5 - May 2008
Volume 20, Issue 4 - Apr 2008
Volume 20, Issue 3 - Mar 2008
Volume 20, Issue 2 - Feb 2008
Volume 20, Issue 1 - Jan 2008
Selecting the target year
Energy Performance Evaluation of a New Commercial Building using Calibrated As-built Simulation with Monitoring Data
Song, Su-Won ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 3, 2008, Pages 155~166
The performance evaluation of a new building is becoming more important because efficient design alone is often not sufficient to deliver an efficient building. However, there is a lack of standard evaluation methods to measure the energy performance of a new construction that has Energy Conservation Design Measures(ECDMs). This study presents an enhanced method based on calibrated whole-building simulation for evaluating the energy performance of new commercial buildings and demonstrates its use using a case-study building, including: an Energy Use Index(EUI) comparison with sub-metered data and an evaluation of the performance of specific ECDMs. The use of this method has determined that the case-study building was shown to use approximately 47% less energy than the base-case building that has the same shape and function as the case-study building(i.e., calibrated as-built simulation mode]), but doesn't include the simulated ECDMs.
The Economic Comparison of EHP and GHP for Medium Capacity Air-conditioning
Kim, Young-Il ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 3, 2008, Pages 167~174
Cost related to building equipment accounts for about 85% of the life cycle cost of buildings. Therefore proper selection of air-conditioning system is important for reducing the overall cost of buildings. In this study, medium capacity EHP and GHP for air-conditioning a building with a floor area of 1,200
are compared economically. To consider all the factors of initial and operation costs effectively, an annual equal payment method is proposed. For the initial cost, cost of equipment, construction, installation, electric facility, financial subsidy and tax cut is considered. Cost of basic electricity, energy(electricity and gas), space charge, labor, insurance and repair is considered for the operation cost. Under the assumptions made in this study, overall cost of EHP is less than that of GHP, but this is not absolute and different outcome may result if different assumptions are made. This study is useful for those who are interested in choosing an air-conditioning system that costs less for mid-size buildings with simple calculations.
A Flow Quantity Distribution Characteristics of the Hot Water Header for Individual Room Control System
Sung, Sun-Kyung ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 3, 2008, Pages 175~180
Flow quantity to supply to a coil in floor heating system is important to achieve comfortable indoor air condition in the winter season. The hot water header is used to distribute the water into the coil. Experimental study has been performed using the water header that have 5 branches consisted of flow control valves and automatic shut-off valves. Each branch line connected it with X-L pipe. Experimental tests accomplished it to investigate the flow distribution characteristics of the hot water header. Experimental results show that the selection of the pump head and differential pressure are very important to save running energy of the system, and high differential pressure needs more friction loss in the case of suitable differential pressure for balancing of the header.
Air-side Performance of Aluminum Heat Exchangers at Different Inclination Angles
Kim, Do-Young ; Cho, Jin-Pyo ; Kim, Nae-Hyun ; Park, Nae-Hyun ; Hwang, Jun-Hyun ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 3, 2008, Pages 181~188
The effect of inclination angle on the heat transfer and pressure drop characteristics of the brazed aluminum heat exchangers is experimentally investigated. Three samples having different fin pitches(1.25, 1.5 and 2.0 mm) were tested. Results show that heat transfer coefficient is not affected by the inclination angle. However, the friction factor increases as the inclination angle increases with negligible difference between the forward and backward inclination. Both the heat transfer coefficient and the friction factor are the smallest at
, followed by
and 1.25mm. Possible explanation is provided considering the louver layout. Comparison with existing correlations is also made.
Performance Test of Liquid Cooling Type Cold Plates for Robot Cooling
Lee, Suk-Won ; Karng, Sarng-Woo ; Hwang, Kyu-Dae ; Kim, Seo-Young ; Rhee, Gwang-Hoon ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 3, 2008, Pages 189~196
The increase of system weight due to installation of cooling devices adds electrical and mechanical loads of humanoid robot, and in return, results in much heat. Therefore, the weight of cooling system is a critical issue for robot cooling. In this study, we propose non-metallic cold plates to deal with such problems. We compare thermal performances between one metallic cold plate and five different types of non-metallic cold plates. A metallic cold plate is totally made of copper. Five non-metallic PC(polycarbonate) cold plates, which are designed to reduce the overall weight of robot cooling system, are composed of a polycarbonate cover with different types of base plate. The overall heat transfer coefficients per unit mass and thermal resistances are obtained for the cold plates. The metallic cold plate shows the best thermal performance. It is interesting to note that the PC cold plate with an aluminum base plate with 18 channels shows the best overall heat transfer coefficient per unit mass. Most polycarbonate cold plates display fairly comparable thermal performance with more reduced system weight compared to the metallic cold plate.
Performance Characteristics of Direct Methanol Fuel Cell with Methanol Concentration
Cho, Chang-Hwan ; Kim, Yong-Chan ; Chang, Young-Soo ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 3, 2008, Pages 197~204
DMFC(Direct Methanol Fuel Cell) is one of promising candidates for power sources of small mobile IT devices like notebook, cell phone, and so on. Efficient operation of fuel cell system is very important for long-sustained power supply because of limited fuel tank size. It is necessary to investigate operation characteristics of fuel cell stack for optimal control of DMFC system. The generated voltage was modeled according to various operating condition; methanol concentration, stack temperature, and load current. It is inevitable for methanol solution at anode to cross over to cathode through MEA(membrane electrode assembly), which reduces the system efficiency and increases fuel consumption. In this study, optimal operation conditions are proposed by analyzing stack performance model, cross-over phenomenon, and system efficiency.
Performance Evaluation of a Dynamic Inverse Model with EnergyPlus Model Simulation for Building Cooling Loads
Lee, Kyoung-Ho ; Braun, James E. ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 3, 2008, Pages 205~212
This paper describes the application of an inverse building model to a calibrated forward building model using EnergyPlus program. Typically, inverse models are trained using measured data. However, in this study, an inverse building model was trained using data generated by an EnergyPlus model for an actual office building. The EnergyPlus model was calibrated using field data for the building. A training data set for a month of July was generated from the EnergyPlus model to train the inverse model. Cooling load prediction of the trained inverse model was tested using another data set from the EnergyPlus model for a month of August. Predicted cooling loads showed good agreement with cooling loads from the EnergyPlus model with root-mean square errors of 4.11%. In addition, different control strategies with dynamic cooling setpoint variation were simulated using the inverse model. Peak cooling loads and daily cooling loads were compared for the dynamic simulation.
Experiments on Heat Transfer Characteristics and Pressure Drop in Micro-channel Plate Heat Exchangers with 3D shapes
Seo, Jang-Won ; Lee, Kyu-Jung ; Kim, Yoon-Ho ; Moon, Chung-Eun ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 3, 2008, Pages 213~219
Microscale heat transfer and microfluidics have become increasingly important to overcome some very complex engineering challenges. The use of very small passages to gain heat transfer enhancement is a well documented method for achieving high heat flux dissipation. In this study, the performance evaluation of micro-channel plated heat exchangers with straight, V-shaped and Y-shaped channels has been experimentally carried out under the counterflow condition. It is found that the mixing effect in V-shaped and Y-shaped channels enhances the heat transfer but pressure drop does not increase seriously in the range of low Reynolds number.