Go to the main menu
Skip to content
Go to bottom
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 27, Issue 12 - Dec 2015
Volume 27, Issue 11 - Nov 2015
Volume 27, Issue 10 - Oct 2015
Volume 27, Issue 9 - Sep 2015
Volume 27, Issue 8 - Aug 2015
Volume 27, Issue 7 - Jul 2015
Volume 27, Issue 6 - Jun 2015
Volume 27, Issue 5 - May 2015
Volume 27, Issue 4 - Apr 2015
Volume 27, Issue 3 - Mar 2015
Volume 27, Issue 2 - Feb 2015
Volume 27, Issue 1 - Jan 2015
Selecting the target year
A Study on the Influence of Boiling Heat Transfer of Nanofluid with Particle Length and Mixing Ratio of Carbon Nanotube
Park, Sung-Seek ; Kim, Woo Joong ; Kim, Jong Yoon ; Jeon, Yong-Han ; Kim, Nam-Jin ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 27, issue 1, 2015, Pages 1~7
DOI : 10.6110/KJACR.2015.27.1.001
A boiling heat transfer system is used in a variety of industrial processes and applications, such as refrigeration, power generation, heat exchangers, cooling of high-power electronics components, and cooling of nuclear reactors. The critical heat flux (CHF) is the thermal limit during a boiling heat transfer phase change; at the CHF point, the heat transfer is maximized, followed by a drastic degradation beyond the CHF point. Therefore, Enhancement of CHF is essential for economy and safety of heat transfer system. In this study, the CHF and heat transfer coefficient under the pool-boiling state were tested using multi-wall carbon nanotubes (MWCNTs) CM-95 and CM-100. These two types of multi-wall carbon nanotubes have different sizes but the same thermal conductivity. The results showed that the highest CHF increased for both MWCNTs CM-95 and CM-100 at the volume fraction of 0.001%, and that the CHF-increase ratio for MWCNT CM-100 nanofluid with long particles was higher than that for MWCNT CM-95 nanofluid with short particles. Also, at the volume fraction of 0.001%, the MWCNT CM-100 nanofluid indicated a 5.5% higher CHF-increase ratio as well as an approximately 23.87% higher heat-transfer coefficient increase ratio compared with the MWCNT CM-95 nanofluid.
Performance Characteristics of Fin-Tube Heat Exchanger having Large Diameter Oval Tube for Dryer
Bae, Kyung-Jin ; Cha, Dong-An ; Kwon, Oh-Kyung ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 27, issue 1, 2015, Pages 8~13
DOI : 10.6110/KJACR.2015.27.1.008
The objective of this paper is to provide design data of fin-tube heat exchanger which have a large diameter oval tube for dryer application. In this study, the heat transfer and pressure drop performance characteristics of the fin-tube heat exchanger were compared with Dittus-Boelter and a new correlation equation using Wilson plot method. The simulation results based on section by section method were compared with experimental results. These results showed that a new correlation equation using Wilson plot method provided better prediction, about 3 to 12%, than the Dittus-Boelter equation, from the experiment comparison. Also, the pressure drop of simulation results showed much more deviation with the experimental results.
A Study on the User and Location Awareness Technology Applied Dimming Lighting Control System to Save Energy
Choi, Kihyun ; Kim, Yongseong ; Lee, Henagwoo ; Seo, Janghoo ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 27, issue 1, 2015, Pages 14~23
DOI : 10.6110/KJACR.2015.27.1.014
Although research and technology developments have recently increased to save lighting energy within buildings, such research and technology development are judged to be unsuitable for energy savings since they are limited in the sense that the application of the technology is fragmented. This study proposes a user and location awareness technology applied to dimming lighting control system and verified the effectiveness of energy savings by building a test bed. The results were as follows : 1) This study suggested a user and location awareness technology applied to dimming lighting control system. 2) The system shows 96.6% and 82.8% energy saving rates, respectively, on the basis of one user, compared to an on/off lighting control and the user and location awareness technology applied to on/off lighting control system. 3) The energy consumption of the user and location awareness technology applied to on/off lighting control system and the user and location awareness technology applied to dimming lighting control system increased to 96.6%, 88.3%, and 59.6% and 82.8%, 85.0%, 51.5%, respectively, on the basis of one, two, and three users, compared to the on/off lighting control system. This study confirmed the energy saving performance of the user and location awareness technology applied to the dimming lighting control system through performance evaluation. In this regard, further study needs to be undertaken to evaluate the performance at night time.
Development of Technology to Secure Refuge Space by Using Existing Restroom
Kim, Ji-Seok ; Shin, Hyun-Joon ; Kim, Jung-Yup ; Park, Byoung-Jik ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 27, issue 1, 2015, Pages 24~30
DOI : 10.6110/KJACR.2015.27.1.024
The fire on a high-rise building would possibly cause fatalities because of ineffective egress due to extended evacuation distance in huge building structure, coupled with dense population, thus requiring secured optimal evacuation method and space. The restroom located in the living space is considered to be useful refuge space which is built with wet pipe and noncombustible materials. This study aimed to develop a system that would make use of the existing restroom as a fire refuge space. Ventilation duct were installed to discharge odor during normal conditions. We could serve the air supply duct to also raise the air pressure in the restroom so as to prevent the toxic gas from gapping around the restroom. The nozzle for the water screen would be installed in restroom door facing the living room to form the water screen which would protect the door. This study is intended to replace the existing refuge space with the restroom in such a way as described above.
Heating Performance of Geothermal Heat Pump System Applied in Cold Climate Region(Mongolia)
Sohn, Byonghu ; Choi, Jae Ho ; Min, Kyung Chon ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 27, issue 1, 2015, Pages 31~38
DOI : 10.6110/KJACR.2015.27.1.031
Geothermal heat pump (GHP) systems have become an efficient alternative to conventional cooling and heating methods due to their higher energy using efficiency. These systems use the ground as a heat source in heating mode operation and a heat sink in cooling mode operation. The aim of this study is to evaluate the heating performance of the GHP system for a residential building (
) in Ulaanbaatar, Mongolia. In order to demonstrate the feasibility of a sustainable performance of this system, we installed the water-to-water geothermal heat pump with ten vertical ground heat exchangers and measured operation parameters from October 19, 2013 to March 26, 2014. The results showed that the entering source temperature of brine from the ground heat exchangers was in a range of the design target temperature of
for heating. For total values of the representative results, the ground heat exchangers extracted heat of 53.51 MWh from the ground. In addition, the GHP system supplied heat of 83.55 MWh to the building and consumed power of 30.27 MWh. Consequently, the average heating seasonal performance factor (
) of the overall system was evaluated to be 2.76 during the measurement period of the heating season.
Economic Analysis of GHG Emission Reduction Methodology in Pulp, Paper and Wood Industry Approved by Korea Voluntary Emission Reduction Program
Kim, Young Min ; Song, Myung Ho ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 27, issue 1, 2015, Pages 39~43
DOI : 10.6110/KJACR.2015.27.1.039
The Energy and Green House Gas target management system was launched by the Korean Government in 2010. The Korea Emission Trading System will start in 2015. Therefore, simultaneous pursuit of energy saving and greenhouse emission reduction through energy use rationalization is an important obligation of Korean engineers, who import about 97% of domestic energy consumption. Economic analysis of the GHG emission reduction methodologies registered and approved by Korea Voluntary Emission Reduction (KVER) program was conducted. The results for waste heat recovery employed in an energy intensive pulp, paper and wood industry were reported. The emission reduction intensities were 9.7 kg
/ton_pulp production. Net Present Value analysis showed that the GHG emission reduction was economically beneficial with an internal rate return of 60%. The results of exergy analysis indicated that the second law efficiencies of waste heat recovery system employed in KVER program were 77.3% and 53.6%. NPV decreased as the exergy decreased.
A Study on Economic Analysis and Performance Appraisal of Compact Type Variable Air Volume
Kim, Dong-Cheol ; Chung, Kwang-Seop ; Kim, Young Il ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 27, issue 1, 2015, Pages 44~49
DOI : 10.6110/KJACR.2015.27.1.044
Ceiling cooling and heating system that consider load arrangement and space in the ceiling needs to be developed. Therefore, experimental and economic changes were done to verify the performance of compact type VAV. The test results were as follow. 1) Noise test result, measuring approximately 50.4 dB~56.6 dB (before ceiling in landfill), had a better ceiling deadline than the current measure, about a 10 dB noise reduction, so that the office baseline (40~50 dB) noise was judged to be less than test. 2) For the static pressure test result, taking out an outside hydrostatic 25 mmAq, 24.8 mmAq was measured, respectively, at the point. 3) For the life-cycle cost analysis result, the initial investment cost, maintenance replacement costs, and maintenance costs increased 0.2%, but the energy savings ratio was 19.5% while the whole life cycle savings of 40 years LCC was reduced 11.9%.
Energy Simulation for Conventional and Thermal-Load Controls in District Heating
Lee, Sung-Wook ; Hong, Hiki ; Cho, Sung-Hwan ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 27, issue 1, 2015, Pages 50~56
DOI : 10.6110/KJACR.2015.27.1.050
Korea district heating systems have mainly used setting temperature control and outdoor reset control. Different from such conventional normal methods, a thermal-load control proposed in Sweden can decrease the return temperature and reduce pump power consumptions because the control is able to provide the appropriate amount of required heat. In this study, further improved predictive optimal control in addition to the conventional controls were simulated in order to verify its effect in district heating system using TRNSYS 17.
apartment housing which accounts for 25% in Korea and is used as a calculation model;. the number of households in the simulation was 9. As a result, a higher temperature difference and decreasing flow rate at primary loop were shown when using thermal-load control.