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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 22, Issue 12 - Dec 2010
Volume 22, Issue 11 - Nov 2010
Volume 22, Issue 10 - Oct 2010
Volume 22, Issue 9 - Sep 2010
Volume 22, Issue 8 - Aug 2010
Volume 22, Issue 7 - Jul 2010
Volume 22, Issue 6 - Jun 2010
Volume 22, Issue 5 - May 2010
Volume 22, Issue 4 - Apr 2010
Volume 22, Issue 3 - Mar 2010
Volume 22, Issue 2 - Feb 2010
Volume 22, Issue 1 - Jan 2010
Selecting the target year
Study on the Performance Characteristics of the Solar Hybrid System with Heat Pump Operating Temperature during Winter Season
Kim, Won-Seok ; Cho, Hong-Hyun ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 12, 2010, Pages 821~827
Study on the performance characteristics of the solar hybrid system with heat pump operating temperature during winter season has performed by using an experimental test. The system performance and operating characteristics with the heat pump operating temperature, hour and load condition were investigated and analyzed. As a result, the hot water temperature was significantly affected by the heat pump operating temperature at the morning(time 1) and noon(time 2). However, hot water temperature was set by the radiation quality and collecting operation hour at the afternoon(time 3). In addition to the solar fraction was decreased for the high heat pump operating temperature because the heat pump operated with a long operating time and short operating period.
An Experimental Study on the Drying Characteristics of Automotive Paint Using Heating Panels and Hot Air
Kim, Sung-Il ; Park, Ki-Ho ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 12, 2010, Pages 828~836
The drying is a process that involves coupled and simultaneous heat and mass transfer. When a wet solid is subjected to thermal drying, two processes occur simultaneously. Drying is classified according to heat transfer characteristics in terms of conduction, convection and radiation. In thermal drying, radiation is easier to control than conduction and convection drying and involves a relatively simple structure. In this study, we measured energy consumption, surface hardness of paint and surface gloss with variation of surface temperature of drying materials and drying time. Drying characteristics and energy consumption between heating panels and hot air heating have been presented. The present study shows that a dryer using heating panels is more effective than a hot air dryer from the viewpoint of energy conservation. The hot air dryer, however, was not optimized and more studies on various parameters related to drying will need to be investigated for definite comparison of drying characteristics of the dryers. The result, even if limited, would present the effective availability of paint drying.
Performance of R1234yf and R1234yf/R134a Mixture under Mobile Air-conditioner Operating Conditions
Park, Ki-Jung ; Lee, Yo-Han ; Choe, Dae-Seong ; Jung, Dong-Soo ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 12, 2010, Pages 837~844
In this study, performance of R1234yf and R1234yf/R134a mixture is measured on a heat pump bench tester in an attempt to substitute R134a used widely in mobile air conditioners (MACs). The bench tester is equipped with a open type compressor providing a nominal capacity of 3.5 kW. All tests are conducted under the summer cooling and winter heating conditions of 7/4
in the evaporator and condenser, respectively. For R1234yf/R134a mixture, measurements are made at 5%, 10%, and 15% of R134a by mass. Test results show that the coefficient of performance (COP) and capacity of R1234yf are up to 2.7% and 4.0% lower than those of R134a, respectively. For R1234yf/R134a mixture, the COP and capacity are up to 3.9% lower and 3.6% higher than those of R134a. For R1234yf and R1234yf/R134a mixture, the compressor discharge temperature is
lower than that of R134a while the amount of charge is reduced up to 11% as compared to R134a. 90%R1234yf/10%R134a is a better refrigerant than pure R1234yf in that it is less flammable and more compatible with existing R134a system. Based upon the results, it is concluded that R1234yf and R1234yf/R134a mixture are long term environmentally friendly solutions to mobile air-conditioners due to their excellent environmental properties with acceptable performance.
A Study on the DSM Effect of a Refrigerant-Subcooling Refrigeration System with an Ice Storage Tank
Kim, Jeong-bae ; Lee, Eun-Ji ; Lee, Dong-Won ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 12, 2010, Pages 845~851
This study was experimentally performed to find the effects of refrigerant subcooling in the refrigeration system and to propose how to get the efficient use of energy. A refrigerant-subcooling refrigeration system consisted of a typical single vapor-compression refrigeration cycle, a subcooler, and an ice storage tank. The degree of subcooling at the exit of the condenser can be increased by the heat transfer between the subcooler and the ice storage tank. The cold heat in the ice storage tank was stored by using the refrigeration cycle during night time and then used to absorb the heat from the subcooler during daytime. The cooling capacity and COP of this system were higher than those of the conventional system due to the increase in the degree of subcooling. Typically, the refrigerant-subcooling system showed superior performance to the conventional refrigeration system and would also contribute to load leveling.
Level Dynamics and Control of the Solution in the High Temperature Generator of an Absorption Chiller
Shin, Young-Gy ; Kwak, Min-Soo ; Cho, Hyun-Wook ; Nam, Sang-Chul ; Jeong, Jin-Hee ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 12, 2010, Pages 852~858
In an absorption chiller, solution is circulated by a solution pump with an inverter to vary flow rate depending on operating conditions. For optimal operation, the solution level in the high temperature generator should be kept constant. However, a sensor for measuring continuous level is not available because of varying solution concentration. Instead, level switches are used and hence feedforward control associated with limit checking is a common practice. In the study, inverter frequencies are estimated from a dynamic simulation model and pump performance. Designed frequencies are compared with those implemented in real chillers. It was found that the frequencies used in real chillers are larger than those needed in circulation flow rates. It was intended to prevent system shut-off caused by dry-out. However, it is necessary to minimize the excessive frequency setting in order to reduce frequent pump stops and the range of solution level for continuous pump operation.
Optimizing the Life Cycle Cost of a Solar Water Heating System in an Office Building Through Simulation
Ko, Myeong-Jin ; Choi, Doo-Sung ; Chang, Jae-D. ; Kim, Yong-Shik ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 12, 2010, Pages 859~866
This study examined the economics of a solar water heating system for an office building using life cycle cost (LCC) optimization simulations. The numerical simulations were conducted with TRNSYS and GenOpt employing the Hooke-Jeeves algorithm. The solar collector area, slope, mass flow rate per collector area and storage tank volume were selected as the main design parameters of the solar water heating system. The LCC optimization simulations of the system were carried out for cases where water temperature was
. The results showed that for water temperature at
the collector area could be decreased by 17% and 28%, storage tank volume could be decreased by 49% and 54%, and mass flow rate per collector area increased by 5% and 9% respectively compared to a non-optimized system. The LCC of the system was reduced by 4% for
and 7% for
. The initial installation cost of the system was reduced by 24% for
and 34% for
. However, the operating cost of the system increased by 16% for
and 36% for
compared to a traditional solar water heating system.
Numerical Analysis on the Improvement of Fume Mixing Ratio in the Push-Pull Local Ventilation System
Yi, Chung-Seob ; Suh, Jeong-Se ; Yoon, Ji-Hoon ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 12, 2010, Pages 867~872
Numerical analysis has been conducted to investigate the fluid flow and fume mixing ratio characteristics of scattering fume in a push-pull ventilation system and optimally improve the flow patterns of scattering fume in the existing ventilation system. This ventilation system has been simulated by using commercial CFD code. In the case of the existing system, although the air is sprayed from air-curtain to prevent the fume from being scattered in upper hood, the improved air supply hood can remove the fume from the wide area in the high pressure. It is verified that the deeper plating storage is more advantageous. Also, by installing the shied around the plating storage, the scattering of the fume to the atmosphere was prevented effectively by surrounding flux.
Computer Simulation to Predict Operating Behavior of a Gas Engine Driven Micro Combined Heat and Power System
Cho, Woo-Jin ; Lee, Kwan-Soo ; Kim, In-Kyu ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 12, 2010, Pages 873~880
The present study developed a computer simulation program to determine the optimum strategy and capacity of a micro combined heat and power(CHP) system. This simulation program considered a part-load electrical/thermal efficiency and transient response characteristics of CHP unit. The result obtained from the simulation was compared with the actual operation of 30 kW gas engine driven micro CHP system. It was found that the simulation could reproduce the daily operation behavior, such as operating hours and mean load factor, closely to the actual behavior of the system and could predict the amount of electrical/thermal output and fuel consumption with the error of less than 12%.
A Study on the Effective Removal Method of Microbial Contaminants in Building According to Bioviolence Agents
Lee, Hyun-Woo ; Hong, Jin-Kwan ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 12, 2010, Pages 881~890
As Influenza A virus(H1N1) has been spreading more rapidly around globe, the study on the airborne disease which is transimitted through the respiratory system is on the rise. In this study, the multizone simulation of the public building against bioviolence is performed in the case of unexpected spread of microbial contaminants, such as bioviolence agent, Influenza A, Smallpox, B. anthrax and transport and control characteristics of above three kinds of bioviolence agents are evaluted. Results suggest that Influenza A and Smallpox which has small mean diameter can be more removable than B. anthrax by using high UVGI grade condition and B. anthrax which has large mean diameter can be more removable than Influenza A and Smallpox by using high filter grade condition. Results also suggest that installing a combined air treatment system is more effective to reduce the damage and engineers will use immune building technology for removing the bioviolence agents effectively.
A Study on the Effects of the Cold Heat Storage with Salt Water on the Performance of a Kimchi Refrigerator
Gil, Bog-Im ; Choi, Eun-Soo ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 12, 2010, Pages 891~896
The objective of the present study is to reveal the effects of a phase-change material on the performance of a Kimchi refrigerator. Two-percent salt water, of which melting temperature was
, was used for the phase-change material. The salt water was packed in silicon cases and inserted between Kimchi container and the copper pipe of the evaporator. The maximum and minimum temperatures of the inner wall of the Kimchi container without salt-water pack were
, which were remarkably improved by using the salt-water packs, resulting
. This shows a useful application of using phase-change materials for accurate temperature controls.
An Experimental Investigation on Noise Reduction Performance of the Absorption and the Resonance Type Duct Silencers
Lee, Young-Sup ; Chung, Kwang-Seop ; Lee, Dong-Hoon ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 22, issue 12, 2010, Pages 897~901
A silencer has been widely used for the purpose of suppressing the noises propagated from duct of air conditioning system. The absorption type silencer is usually applied to reduce the noise with high frequency bandwidth. On the order hand, the resonance type silencer is applied to reduce the noise with low-middle frequency bandwidth. The insertion loss of silencer is measured in the reverberation room. The cut-off frequency of reverberation room is 100 Hz. The insertion loss of absorption type silencer is more larger than that for resonance type silencer regardless of changing the flow velocity.