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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
Thermal Comfort and Air Flow Patterns for Indoor Unit Positions and Ventilation Rates in Cooling Operation
Koh, Jae-Yoon ; Kang, Tae-Wook ; Park, Yool ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 4, 2008, Pages 221~229
This study analyze indoor thermal comfort properties such as PMV, PPD and fluid variables when the cooling loads are light, occupant and ventilation. There are 6 cases to study for the indoor unit installation conditions and ventilation rates. Numerical method is used to study the indoor environmental properties and experimental study is adapted to analyze reaching time by variable cooling load conditions.
Performance Characteristics of a CO
Cooling and Water Heating System with a Twin-rotary Compressor
Cho, Hong-Hyun ; Lee, Ho-Sung ; Baek, Chang-Hyun ; Kim, Yong-Chan ; Cho, Sung-Wook ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 4, 2008, Pages 230~237
The objective of this paper is to investigate the performance characteristics of a
cooling and water heating system using a twin-rotary compressor with the compression volume ratio of 0.6. The cooling performances of the
heat pump were measured and analyzed with the variations of charge amount, EEV opening, and compressor frequency. In addition, the performance of the combined system including cooling and water heating was also measured and analyzed by varying inlet temperature of the EEV. As a result, the optimal normalized charge and cooling COP in the cooling mode were 0.307 and 2.06, respectively. The application of the water heating into the
heat pump improved the cooling performance over 78% and decreased the EEV inlet temperature by
, which can increase system reliability.
A Study on Improvement of Industrial Hood in Ventilation System for Elimination of Harmful Material and Dust
Kim, Young-Sun ; Oh, Yool-Kwon ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 4, 2008, Pages 238~244
This study investigates on the improvement of inhalation effect of hood which attached new device named as "gas-guide-device" in local exhaust ventilation system for the effective elimination of harmful material and dust in manufacturing factory. The gas-guide-device having a diamond shape is composed of width (b) and two sides of a device (X, Y) and its size is selected the industrial hood under application in manufacturing factory after due consideration. In order to investigate the effect of gas-guide-device, numerical and experimental study is performed that the flow velocity is calculated and is measured by a commercial program "COMSOL
" and a hot wire type of anemometer, respectively. The numerical and experimental results are revealed is a similar pattern and flow velocity has improved to hood attached gas-guide-device. Also, the numerical method and result is also verified the dependance. Moreover, the optimum shape and size of gas-guide-device is revealed that the width (b) and the ratio of two sides of gas-guide-device (X, Y) has 125mm and 4 to 6.
Experimental Study on the Performance Improvement of a Simultaneous Heating and Cooling Heat Pump in the Heating-main Operating Mode
Kang, Hoon ; Jung, Hyen-Joon ; Joo, Young-Ju ; Kim, Yong-Chan ; Choi, Jong-Min ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 4, 2008, Pages 245~251
The cooling load in winter is significant in buildings and hotels because of the usage of office equipments and the high efficiency of wall insulation. Hence, the development of a multi-heat pump that can cover heating and cooling simultaneously for each indoor unit is required. In this study, the operating characteristics and performance of a simultaneous heating and cooling heat pump in the heating-main operating mode were investigated experimentally. The system adopted a variable speed compressor with four indoor units and one outdoor unit with R-410A. In the heating-main mode, the cooling capacity was lower than the design cooling capacity due to the reduction of the flow rate in the indoor unit for the cooling, with the increase of the heating capacity. To solve these problems, the performance characteristics of the simultaneous heating and cooling heat pump in the heating-main mode were investigated by varying the flow rate to the indoor unit for the cooling and the compressor rotating speed. In addition, the adequate control methods were suggested to improve the system efficiency.
A Study on the Microbial Contaminant Transport and Control Method According to Government Building Bio- Attack
Lee, Hyun-Woo ; Choi, Sang-Gon ; Hong, Jin-Kwan ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 4, 2008, Pages 252~259
The purpose of this study is to estimate the movement of microbial contaminant caused by bio-attack using bio-agent such as bacillus anthracis for preventing contaminant diffusion. multizone simulation was carried out in the case of three types of bio-attack scenario in the government building. Simulation results show that severe contaminant diffusion is brought about in all cases of bio-attack scenario in one hour, though pollution boundaries have different mode according to bio-attack scenarios. Simulation results also show that immune building technology such as filter and UVGI technology gives us powerful alternatives to meet the emergent situation caused by unexpected bio-attack.
An Experimental Study of a Water Type Glazed PV/Thermal Combined Collector Module
Kim, Jin-Hee ; Kim, Jun-Tae ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 4, 2008, Pages 260~265
The excess heat that is generated from PV modules can be removed and converted into useful thermal energy. A photovoltaic/thermal (PVT) module is a combination of photovoltaic module with a solar thermal collector, forming one device that converts solar radiation into electricity and heat simultaneously. In general, two types of PVT can be distinguished : glass-covered PVT module, which produces high-temperature heat but has a slightly lower electrical yield, and uncovered PVT module, which produces relatively low-temperature heat but has a somewhat higher electrical performance. In this paper, the experimental performance of water type PVT combined module, glass-covered, analyzed. The electrical and thermal performance of the module were measured in outdoor conditions, and the results are analyzed. The results showed that the thermal efficiency of the PVT module was 27.6% average and its PV efficiency was about 10.0% average, both depending on solar radiation, inlet water temperature and ambient temperature.
Phase Equilibrium Conditions of Gas Hydrates for Natural Gas Solid Transportation and Storage
Jeon, Yong-Han ; Kim, Jong-Yoon ; Kim, Chong-Bo ; Kim, Nam-Jin ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 4, 2008, Pages 266~273
Natural gas hydrates are ice-like solid substances, which are composed of water and natural gas, mainly methane. They have three kinds of crystal structures of five polyhedra formed by hydrogen-bonded water molecules, and are stable at high pressures and low temperatures. They contain large amounts of organic carbon and widely occur in deep oceans and permafrost regions. Therefore, they are expected as a potential energy resource in the future. Especially,
natural gas hydrate contains up to
of methane gas, de pending on the pressure and temperature of production. Such large volumes make natural gas hydrates can be used to store and transport natural gas. In this study, three-phase equilibrium conditions for forming natural gas hydrate were numerically obtained in pure water and single electrolyte solution containing 3 wt% NaCl. The results show that the predictions match the previous experimental values very well, and it was found that NaCl acts as an inhibitor. Also, help gases such that ethane, propane, i-butane, and n-butane reduce the hydrate formation pressure at the same temperature.
Development of Nano Ceramic Structures for HEPA Type Breathing Wall
Kim, Jong-Won ; Ahn, Young-Chull ; Kim, Gil-Tae ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 4, 2008, Pages 274~279
In the perspective of saving energy in buildings, high performance of insulation and air tightness for improving the heating and the cooling efficiency has brought the positive effect in an economical view. However, these building energy saving technologies cause the lack of ventilation, which is the direct cause of increasing the indoor contaminants, and it is also very harmful to residents because they spend over 90% of their time in the indoor area. Therefore, the ventilation is important to keep indoor environment clean and it can also save energy consumption. In this study, a HEPA type breathing wall is designed as a passive ventilation system to collect airborne particles and to supply fresh outdoor air. To make fine porous structures, polymer nano fibers which were made by electro spinning method are used as a precursor. The nano fibers are coated with SiO2 nano particles and finally the HEPA type breathing wall is made by sintering in the electric furnace at
. The pressure drops of nano ceramic structure are 8.2, 25.5 and 44.9 mmAq at the face velocity of 2.0, 5.9 and 8.8 cm/s, respectively. Also the water vapor permeability is
. In this research, the porous nano ceramic structures are obtained and the possibility for the usage of a material for HEPA type breathing wall can be obtained.
A Characteristics Simulation of Heat Pump System for Sewage Water as a Heat Source
Park, Il-Hwan ; Chang, Ki-Chang ; Lee, Young-Soo ; Yoon, Hyung-Kee ; Baek, Young-Jeen ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 4, 2008, Pages 280~286
In this study, characteristics simulation of heat pump system is investigated for heating and cooling using sewage water as a heat source. A simulation program for preestimate operation characteristics of heat pump system is developed. The performance of this system is resolved by several variables and the characteristics which is based on actual air and sewage temperature data. The simulation results agree well with the experimental values of COP. In the analysis of system characteristics, the COP is changed between
in winter season for heating load,
in summer season for cooling load. As the results of Life Cycle Cost analysis over a 15 year life cycle, the energy cost could be reduced by 250 million won if a heat pump system was used instead of a conventional boiler and an absorbtion refrigerator on the office building.
Evaluation of Thermal Comfort in Ceiling Cooling System
Lee, Ju-Youn ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 20, issue 4, 2008, Pages 287~293
The purpose of this study was to clarify the effects of air and ceiling temperatures on a type of ceiling cooling system that involves cool water circulation. The experiment is conducted in summer. The subjects (11 young females) are exposed to the following conditions: combinations of air temperatures
and ceiling temperature of
in still air and RH 50%. The following results were obtained; the thermal sensation vote is neutral at a mean skin temperature of
. The ceiling temperature affected different parts of the body. For example, the forehead, scapula and abdomen produced different skin temperatures. Thermal comfort vote was rated as comfortable at high temperature environment. The satisfaction from the ceiling temperature was valued comfortable zone in this experiment. Mean skin temperature showing higher thermal neutrality temperature than existing studies for floor and wall radiation cooling results.