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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
Numerical Simulation of Smoke Ventilation in Rescue Route and Cross Passage of Railroad Tunnel
Yang, Sung-Jin ; Hur, Nahm-Keon ; Ryou, Hong-Sun ; Kim, Dong-Hyeon ; Jang, Yong-Jun ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 1, 2008, Pages 1~10
A transient 3-D numerical simulation was performed to analyze the fire safety in a railway tunnel equipped with a mechanical ventilation system. The behavior of pollutants was studied for the emergency operation mode of ventilation system in case of fire in the center of the rescue station and near the escape route. Various schemes of escape route construction for connection angle(
) and slope(
) were evaluated for the ventilation efficiency in the fire near the escape route. From the results, it was shown that the mode of the ventilation fan operation which pressurizes the tunnel not under the fire and ventilates the smoke from the tunnel under the fire is most effective for the smoke control in the tunnel in case of the fire occurrence. It was also shown that the blowing of jet fan from the rescue tunnel to the main tunnel should be in the same direction as the flow direction in the main tunnel arising from the traffic and the buoyancy.
An Experimental Study on the Thermal Load of a Cryochamber with Radiation Shields
Kim, Young-Min ; Kang, Byung-Ha ; Park, Seong-Je ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 1, 2008, Pages 11~16
Infrared (IR) detectors are widely used for such applications as thermoelastic stress analysis, medical diagnostics and temperature measurement. Infrared detectors commonly need to be refrigerated below 80 K, and thus a cooling system should be equipped together with the detector system. The cooling load, which should be removed by the cooling system to maintain the nominal operating temperature of the detector, critically depends on the insulation efficiency of the cryochamber housing the detector. Thermal load of a cryochamber is attributed to the conduction heat transfer through a cold finger, the gases conduction and radiation heat transfer. The thermal loads of an infrared detector cryochamber with a radiation shield are investigated experimentally in present study. Since the effect of radiation heat transfer on thermal loads is significant, radiation shields is installed in the cold finger part to protect heat input through radiation.
Improving Vertical Airflow Uniformity Considering the Structures of the Lower Plenum in a Cleanroom
Kim, Young-Sub ; Ha, Man-Yeong ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 1, 2008, Pages 17~25
To achieve the unidirectional airflow in a cleanroom, we need to predict accurately the static pressure losses at the lower plenum and to control properly the opening pressure ratio of access floor panels based on these pressure losses. At first, the present study proposed a correlation to predict the velocity distribution at the lower plenum, because the accuracy to predict pressure losses at the lower plenum depends on how to calculate the velocity correctly against the inner structures at the lower plenum. In the second place, this study proposed correlations which considered the effect of inner structures such as columns, ducts and equipments at the lower plenum on pressure losses. In order to test the accuracy of these correlations, we compared air flow patterns before regulating the opening ratio of access floor with those after regulating. Results after regulating the opening ratio of access floor show good unidirectional uniform airflow pattern. So the present method can be used as an important tool to control the air flow in a cleanroom.
A Study on the Performance of Heat Recovery Ventilators for Apartment Houses
Chang, Hyun-Jae ; Hong, Seok-Jin ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 1, 2008, Pages 26~34
Heat recovery ventilator(HRV) is recommended to improve indoor air quarlity (IAQ) and energy conservation in apartment houses. Recently, in Korea, HRV is produced from many manufacturers. However, there have been not so many experiences to apply HRV in apartment houses and verification on the performance such as heat exchange efficiency, carry-over rate, internal leakage, etc. have not been carried out sufficiently. So in this study, fan performance, heat exchange efficiency, air leakage, internal exhaust leakage, external leakage and sound level of HRV were examined for selected HRV models under domestic and international standard. Results of performance test, there were need to improve latent heat exchange efficiency and sound level of HRV.
Analysis of Heat Loss with Mirror Array and Receiver Shapes on the Dish Solar Collector
Seo, Joo-Hyun ; Ma, Dae-Sung ; Kim, Yong ; Kang, Yong-Heack ; Seo, Tae-Beom ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 1, 2008, Pages 35~41
The radiative heat loss from a receiver of a dish solar collector is numerically investigated. The dish solar collector considered in this paper consists of a receiver and multi-faceted mirrors. In order to investigate the performance comparison of dish solar collectors, six different mirror arrays and four different receivers are considered. A parabolic- shaped perfect mirror of which diameter is 1.40 m is considered as the reference for the mirror arrays. The other mirror arrays which consist of twelve identical parabolic-shaped mirror facets of which diameter are 0.405 m are suggested for comparison. Their reflecting areas, which are 1.545
, are the same. Four different receiver shapes are a conical, a dome, a cylindrical, and a unicorn type. The radiative properties of the mirror surfaces and the receiver surfaces may vary the thermal performance of the dish solar collector so that various surface properties are considered. In order to calculate the radiative heat loss in the receiver, two kinds of methods are used. The Net Radiation Method that is based on the radiation heat balance on the surface is used to calculate the radiation heat transfer rate from the inside surface of the receiver to the environment. The Monte-Carlo Method that is the statistical approach is adopted to predict the radiation heat transfer rate from the reflector to the receiver. The collector efficiency is defined as the results of the optical efficiency and the receiver efficiency. Based on the calculation, the unicorn type has the best performance in receiver shapes and the STAR has the best performance in mirror arrays except the perfect mirror.
Numerical Investigation of Energy Separation Process in a Ranque-Hilsch Vortex Tube
Son, Chang-Ho ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 1, 2008, Pages 42~48
A numerical simulation has been conducted to investigate the physics of the Ranque-Hilsch vortex tube. Even though currently available turbulent models cannot predict such complex flow accurately, it was expected that the simulation would enlighten underlying physics qualitatively. The balance of energy on a fluid particle moving along some typical streamlines through shear work and heat transfer was investigated to explain the physics of energy separation process. It was found that the heat transfer cancels major part of the energy separation done by shear work. It was also found that the most of energy separation occur near inlet and hot outlet.
Performance of a Refrigerant Heating Type Heat Pump by Changing of Driving Devices and Heat Exchangers
Park, Youn-Cheol ; Kim, Sang-Hyuk ; Kim, Ji-Young ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 1, 2008, Pages 49~56
When the outdoor air temperature decreased less than the freezing temperature, frost forms at the surface of heat exchangers and it makes the performance degradation of a heat pump system. In this study, a heat pump system has been developed which has a refrigerant heating device as an auxiliarly heating equipment. To reduce power consumptions of the system, a liquid pump, rather than a compressor, was used to drive refrigerant in the heat pump cycle. Ratio of refrigerant mass flow between a refrigerant heating heat exchanger(GHX) and a outdoor plate heat exchanger(PHX) was varied and the system performance was measured and analyzed. As results, when the refrigerant flow rate to the GHX was decreased, the system performance is decreased due to heat absorption capability restriction of the GHX and small variation of the power consumption in the compressor. The effect on the evaporating and condensing pressure by the distribution ratio of the refrigerant to the each heat exchanger is small compare to the effect by the frequency change in the compressor. When the compressor was replaced by the liquid pump, the capacity of the system decreased a little, however the power consumption decrease approximately 80% compare with the power used in the compressor.
A Study on Operating Method by Energy Evaluation and Performance Evaluation of Heat Recovery Ventilator According to Outdoor Conditions
Kim, Kwang-Hyun ; Yee, Jurng-Jae ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 1, 2008, Pages 57~64
Recently, regulation of ventilator installation and its details has been revised and the establishment of heat recovery ventilator in newly built apartments has been obligated. This study was done to offer the method of operation and design of heat recovery ventilator to save energy by measuring its efficiency and comparing with the results of experiment. This paper confirmed that it is desirable to operate heat recovery ventilator by using "by-pass mode" within
scope of the difference indoor absolute humidity in spring and autumn and outdoor absolute humidity and heat recovery ventilator of energy saving effect is better than constant air volume system.
Study on the Simulation of Heat Pump Heating and Cooling Systems to Resident Building
Choi, Young-Don ; Han, Seong-Ho ; Cho, Sung-Hwan ; Kim, Du-Sung ; Um, Chul-Jun ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 1, 2008, Pages 65~74
In Korea, air source heat pump system is less efficient than conventional heat source facilities, such as ground source, river water, because the air temperature in winter season is so low that COP of air source heat pump system drops below 3.0. Therefore, the study on the application of heat pump heating and cooling systems is crucial for the efficient popularization of heat pump. In this work, we present the dynamic analysis of energy consumption for the large resident building by heat resistance-capacitance method. The system simulation of water storage air source heat pump is additionally performed by changing of sizes and locations of the hospital building. The computed results show that energy cost of water storage air source heat pump is low, so it is more economical than absorption chiller & heater.
Air Handling Unit Utilizing Water/Air Direct Contact Heat Exchanger with Mesh
Jeon, Yong-Han ; Kim, Jong-Yoon ; Kim, Nam-Jin ; Seo, Tae-Boem ; Kim, Chong-Bo ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 1, 2008, Pages 75~80
The objective of this research was to investigate the enhancement of heat transfer by mesh in water/air direct contact air conditioning system. Mesh is inserted as a turbulent promoter in front of the water injection nozzle. The heat transfer characteristics with and without mesh and the effect of the number of inserted mesh and mesh porosity size have been studied experimentally. Inserted mesh improves heat transfer efficiency compared to non~inserted mesh system and heat transfer efficiency increased as the number of mesh is increased. Meanwhile, heat transfer efficiency decreased as the porosity of the mesh is increased. With inserted mesh, inlet and outlet temperature difference of air increased more than 50%. Heat exchange time of water/air to reach the 100% humidity decreased less than 30%. This result shows inserted mesh can enhance the performance of the water/air direct contact air conditioning system.