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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 :
Lee, Dae Young
Volume & Issues
Volume 26, Issue 12 - Dec 2014
Volume 26, Issue 11 - Nov 2014
Volume 26, Issue 10 - Oct 2014
Volume 26, Issue 9 - Sep 2014
Volume 26, Issue 8 - Aug 2014
Volume 26, Issue 7 - Jul 2014
Volume 26, Issue 6 - Jun 2014
Volume 26, Issue 5 - May 2014
Volume 26, Issue 4 - Apr 2014
Volume 26, Issue 3 - Mar 2014
Volume 26, Issue 2 - Feb 2014
Volume 26, Issue 1 - Jan 2014
Selecting the target year
Analysis of Performance of Heat Pump System with Flue Gas Heat Recovery through Field Test
Lee, Seung-Ho ; Lee, Gil-Bong ; Lee, Young-Soo ; Park, Sang-Il ; Ko, Chang-Bok ; Baik, Young-Jin ; Lee, Kwan-Soo ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 26, issue 1, 2014, Pages 1~7
DOI : 10.6110/KJACR.2014.26.1.001
A field test of a 70 kW heat pump system with flue gas heat recovery was performed by an experiment at the Korea Institute of Energy Research. The flue gas is exhausted from a 320 RT absorption chiller-heater in the heating season. Using this flue gas, source water of the heat pump is heated by a condensed-type heat exchanger in the chimney. The operating characteristics of the heat recovery heat pump system were analyzed. Based on the results of the experiments, operating maps were obtained, and an optimum operating range is suggested, in which the return and heat source water temperature are
, respectively. Additionally, economic analysis of this system was conducted and about 50% energy cost savings can be expected in the heating season.
Enhancement of Stratification for Solar Water Storage Tank with Spiral Jacket and Coil(Part 2 Simulation)
Lee, Seong Hoon ; Son, Hyo Seok ; Hong, Hiki ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 26, issue 1, 2014, Pages 8~14
DOI : 10.6110/KJACR.2014.26.1.008
We have performed experiments to enhance the stratification in a storage tank in order to raise the collector efficiency and solar fraction in solar thermal systems. The storage tank with a spiral jacket in the side wall has a scroll-shaped heat exchanger coil added to the upper part. The performance was compared between only the side and upper-side heating part through simulation using TRNSYS under the same weather conditions and initial conditions. As a result, the upper-side heating has a 4.2% advantage in solar fraction, but almost no increase in collector efficiency.
Improvement of University Education for Supplying Technical Manpower for Plant Engineering Industry in the Architectural Engineering Field
Shim, Hyun-Sun ; Kim, Young-Il ; Chung, Kwang-Seop ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 26, issue 1, 2014, Pages 15~20
DOI : 10.6110/KJACR.2014.26.1.015
In this study, improvement of university education is suggested so that university graduates in Architectural Engineering can work in the plant engineering industry without major retraining, which is generally required by plant engineering companies. Before the disposition of manpower to a plant engineering site, new recruits are retrained for about 2~3 years, since university education is neither sufficient, nor appropriate to handle plant engineering tasks. It is necessary to implement practical plant engineering into university education, so that graduates can work effectively in plant engineering fields, without major retraining. For a case study of an S2 University located in Seoul, it is enough to supplement the interdisciplinary program with plant engineering subjects, if proper texts are developed. To replace the plant engineering education offered by the company with university education, the following measures should be taken. First, basic plant engineering should be taught for 15 hours. Second, education on design and drawings should be reinforced.
A Study on a Drying Machine with Microwave at Vacuum Condition for Discarded Citrus Scrapes
Ko, Gwang-Soo ; Park, Youn Cheol ; Yoon, Hyung-Kee ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 26, issue 1, 2014, Pages 21~25
DOI : 10.6110/KJACR.2014.26.1.021
A drying machine for discarded Citrus scrap was developed in this study. The Citrus produced in Jeju Province was treated as wastes (a) after making a beverage, such as drinking juice, and (b) if the size of the product did not fit with its agricultural product criteria. Various types of drying machine were developed in this study, and different kinds of technologies were combined improve the performance. To enhance the performance, the system was maintained in a vacuum state, and a high frequency micro wave was activated to the waste Citrus scrap, to heat up the moisture inside the Citrus kernels. The frequency of the micro-wave was 2.6 GHz, which is the resonant frequency of the molecules. Experiments were conducted with a vacuum of 50, 100, 150, 300, 500, and 700 mbar. The waste Citrus scrap has two types of status : (a) original scrap, and (b) mixed with blender. As results, specimen (a) shows a 0.13 g/sec evaporation rate, while specimen (b) shows a 0.19 g/sec rate, at 50 mbar of environment vacuum condition. For the drying efficiency, specimens (a) and (b) show 0.15 g/W and 0.24 g/W, respectively.
Experimental Study of Cooling Energy Saving Verification Using Blinds and Phase Change Material(PCM)
Song, Young-Hak ; Kim, Ki-Tae ; Koo, Bo-Kyung ; Lee, Keon-Ho ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 26, issue 1, 2014, Pages 26~31
DOI : 10.6110/KJACR.2014.26.1.026
This study looks into changing building energy use by application of phase change material (PCM). PCM does not need extra energy for operation and is used for reducing building energy use and, CO2 output by displaying semi-permanent effects after installation. It also is able to avoid the maximum electric power time-zone by inducing a time lag phenomenon of cooling and heating loads with high thermal capacity using latent heat. To verify the efficiency of blinds and PCM, tests about the PCM operation mechanism using air conditioning machinery and nocturnal panel cooling were done. In the test results of the case using PCM installation, a
blind angle with machinery air conditioning and nocturnal panel cooling at the same time shows a 22 percent energy saving effect against general space. The test results of each case were compared and analyzed based on the blind and window opening settings. Finally, the energy reduction of existing buildings using PCM application was reviewed based on the final measurement results.
Thermal Contact Resistance Measurement of Metal Interface at Cryogenic Temperature
Kim, Myung Su ; Choi, Yeon Suk ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 26, issue 1, 2014, Pages 32~37
DOI : 10.6110/KJACR.2014.26.1.032
The thermal contact resistance (TCR) is one of the important resistance components in cryogenic systems. Cryogenic measurement devices using a cryocooler can be affected by TCR because the device has to consist of several metal components that are in contact with each other for heat transfer to the specimen without a cryogen. Therefore, accurate measurement and understanding of TCR is necessary for the design of cryogenic measurement devices using a cryocooler. The TCR occurs at the interface between metals and it can be affected by variable factors, such as the roughness of the metal surface, the contact area and the contact pressure. In this study, we designed a TCR measurement system at variable temperature using a cryocooler as a heat sink. Copper was selected as a specimen in the experiment because it is widely used as a heat transfer medium in cryogenic measurement devices. We measured the TCR between Cu and Cu for various temperatures and contact pressures. The effect of the interfacial materials on the TCR was also investigated.
A Comparison of the Design Loads of a Water Supply System
Lee, Yong-Hwa ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 26, issue 1, 2014, Pages 38~41
DOI : 10.6110/KJACR.2014.26.1.038
Fixture units and the diversity curve are used, in order to determine the required size of water supply pipe. However, the values of the National Plumbing Code, International Plumbing Code and National Standard Plumbing Code of America are not the same. The objective of this study is to comparatively analyze the fixture units and the peak flows of a 10th story office building, at any instant of time, according to the three codes.
Numerical Study on the Humidification Efficiency of Humidifying Module Shapes of the Evaporative Humidifier
Kim, H.K. ; Ohm, T.I. ; Moon, S.H. ; Yoon, H.K. ; Bang, K.Y. ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 26, issue 1, 2014, Pages 42~47
DOI : 10.6110/KJACR.2014.26.1.042
Adequate relative humidity is needed in the common living space, for human health, and industrial space, for maintenance and efficiency. Evaporative humidifier systems generally have slow response tendencies of air loads, but relatively low initial investment and maintenance costs. Humidification efficiency in the evaporative humidifier is dependent mostly on the shapes and arrays of humidifying modules. So, we tried to apply the computational fluid dynamics to the evaporative humidifier systems, and studied the humidification efficiency of evaporative humidifiers, through the outlet air conditions.
Theoretical Analysis of a Recuperative Refrigeration Dehumidifier
Kim, Dong-Seon ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 26, issue 1, 2014, Pages 48~54
DOI : 10.6110/KJACR.2014.26.1.048
A refrigeration dehumidifier with a recuperative heat exchanger is theoretically analyzed. The recuperative heat exchanger is located between the two air streams from and to the dehumidifying coil, and reduces the sensible heat load in dehumidification process. A simple model is developed to predict performance of the dehumidifier. The model predicts that the recuperative heat exchanger is effective especially in the low humidity condition, where the sensible heat load is relatively large. It is predicted that, by adopting a recuperative heat exchanger, a maximum 30~110% increase in COP is possible for indoor air at
, and 40~60% relative humidity.