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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 19, Issue 12 - Dec 2007
Volume 19, Issue 11 - Nov 2007
Volume 19, Issue 10 - Oct 2007
Volume 19, Issue 9 - Sep 2007
Volume 19, Issue 8 - Aug 2007
Volume 19, Issue 7 - Jul 2007
Volume 19, Issue 6 - Jun 2007
Volume 19, Issue 5 - May 2007
Volume 19, Issue 4 - Apr 2007
Volume 19, Issue 3 - Mar 2007
Volume 19, Issue 2 - Feb 2007
Volume 19, Issue 1 - Jan 2007
Selecting the target year
Theoretical Analysis on the Applications of the Double-Floor Ondol System
Choi, Won-Ki ; Lee, Kang-Young ; Lee, Hyun-Geun ; Suh, Seung-Jik ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 19, issue 5, 2007, Pages 355~363
The Korean traditional 'Ondol' system has been a target for innovation to meet the requirements of sustainable domestic building and low carbon emission energy utilization. Simulation techniques provide designers and researchers with powerful tools to predict heating load and thermal behaviour of Ondol systems installed in various contexts. However, there are few studies on Ondol models, especially associated with multi-stories buildings of which type covers about 50% of Korean housing stock. In this study, we analyzed the double floor Ondol system on the multi-stories buildings using the ESP-r program. On the basis of the double floor Ondol system, we suggested the new modelling method that is composed of the Vent zone and Ondol zone. Using the this model, sensitivity analysis was carried out to refine the applicability of the model taking account of control conditions, constructions, air change and air flow network method and CFD analysis using the FLUENT. The air layer has enough temperature to use in heating zone. It is suggested that the simplicity of the model will allow building designers and mechanical engineers easily to implement scenario-based assessments of design options as well as control strategies. Later, we will simulate the real buildings and analyze the air distributions using the Fluent according to the various conditions.
Effect of the Balcony Space on Thermal Environment and Heating/Cooling Load in an Apartment House
Seo, Jung-Min ; Choi, Young-Jin ; Song, Doo-Sam ; Chang, Hyun-Jae ; Kim, Sang-Jin ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 19, issue 5, 2007, Pages 364~371
The former studies for expanding a balcony space were tend to be focused on only quantitative aspects. In this study, the characteristics of balcony space on thermal on vironment in apartment house were analysed. First, the effect of the balcony space on thermal environment of living space was analysed by field measurement. Second, the temperature distribution of the bedroom and heating/cooling load with the balcony expansion were analysed by numerical simulation.
Dynamic Simulation of Ground Source Heat Pump with a Vertical U-tube Ground Heat Exchanger
Lee, Myung-Taek ; Kim, Young-Il ; Kang, Byung-Ha ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 19, issue 5, 2007, Pages 372~378
GHX (Geothermal Heat Exchanger) design which determines the performance and initial cost is the most important factor in ground source heat pump system. Performance of GHX is strongly dependent on the thermal resistance of soil, grout and pipe. In general, GHX design is based on the static simulation program. In this study, dynamic simulation has been peformed to analyze the variation of system performance for various GHX parameters. Line-source theory has been applied to calculate the variation of ground temperature. The averaged weather data measured during a 10-year period
in Seoul is used to calculate cooling and heating loads of a building with a floor area of
. The simulation results indicate that thermal properties of borehole play significant effect on the overall performance. Change of grout thermal conductivity from 0.4 to
increases COP of heating by 9.4% and cooling by 17%. Change of soil thermal conductivity from 1.5 to
increases COP of heating by 13.3% and cooling by 4.4%. Change of GHX(length from 100 to 200 m increases COP of heating by 10.6% and cooling by 10.2%. To study long term performance, dynamic simulation has been conducted for a 20-year period and the result showed that soil temperature decreases by
, heating COP decreases by 2.7% and cooling COP decreases by 1.4%.
Numerical Simulation of Ventilation in the Storage Hall of Tripitaka Koreana at Haein Temple in Case of Building Rearrangement
Hur, Nahm-Keon ; Lee, Myung-Sung ; Yang, Sung-Jin ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 19, issue 5, 2007, Pages 379~385
In the present study, ventilation flow in the Janggyeongpan-Jeon at Haein temple in case of building rearrangement has been investigated numerically. To achieve more accurate results, detailed shapes such as buildings and the window grills are modeled and tree canopy model is adopted to account for the effect of trees in the computation. Wind velocities as boundary condition are taken from meteorological statistical data. The numerical results show that ventilation flow distributions at Janggyeongpan-Jeon in case of building rearrangement are nearly similar to those before rearrangement.
Ventilation Analysis according to Jet Fan Location in Long Tunnel
Kang, Shin-Hyung ; Byun, Ju-Suk ; Lee, Jin-Ho ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 19, issue 5, 2007, Pages 386~393
This paper studies the ventilation characteristics according to the jet fan location at the long road tunnel using the CFD software 'FLUENT' which is based on the finite volume method. The tunnel model used in the analysis has a length of 1600m, a cross sectional area of
, and is composed of 3 lanes and one way. The velocity profile, the distribution of CO concentration and the ventilation flow rate within the tunnel are analyzed, respectively. In the analysis, it is found that the dependence of the ventilation flow rate upon the jet fan location is small, but the CO concentration in the tunnel is at the lowest when the jet fans are installed near the tunnel outlet. An air stream right below the jet fan is almost inactive due to the strong stream injection near the jet fan. Thus, the pollution level below the jet fan must be higher than the other area.
A Study on Prediction of Temperature and Humidity for Estimation of Cooling Load
Yoo, Seong-Yeon ; Lee, Je-Myo ; Han, Kyou-Hyun ; Han, Seung-Ho ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 19, issue 5, 2007, Pages 394~402
To estimate the cooling load for the following day, outdoor temperature and humidity are needed in hourly base. But the meteorological administration forecasts only maximum and minimum temperature. New methodology is proposed for predicting hourly outdoor temperature and humidity by using the forecasted maximum and minimum temperature. The correlations for normalized outdoor temperature and specific humidity has been derived from the weather data for five years from 2001 to 2005 at Seoul, Daejeon and Pusan. The correlations for normalized temperature are independent of date, while the correlations for specific humidity are linearly dependent on date. The predicted results show fairly good agreement with the measured data. The prediction program is also developed for hourly outdoor dry bulb temperature, specific humidity, dew point, relative humidity, enthalpy and specific volume.
Performance of Alternative Refrigerants for R12 and R134a in Automobile Air-Conditioners
Baek, In-Cheol ; Park, Ki-Jung ; Shim, Yun-Bo ; Jung, Dong-Soo ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 19, issue 5, 2007, Pages 403~410
In this study, natural refrigerants and their mixtures that can supplement and replace R12 and R134a in automobile air-conditioners are studied. R134a is currently used as the refrigerant in new motor vehicle air conditioners, replacing the ozone depleting refrigerant R12. Although R134a has no ozone depletion potential, it has a relatively large global warming potential, approximately 1300 times that of
over a 100 year time horizon. For this reason, performance of natural refrigerants and their mixtures containing R152a, RE170 (Dimethylether, DME) and R600a (Isobutane) are measured under 2 different temperature conditions. They were tested in a refrigerating bench tester with an open type compressor. The test bench provided about 4 kW capacity and water and water/glycol mixture were employed as the secondary heat transfer fluids. Test results show that the coefficient of performance (COP) of these refrigerants is up to 21.55% higher than that of R12 in all temperature conditions. Overall, these fluids provide good performance with reasonable energy savings without any environmental problem and thus can be used as long term alternatives for automobile air-conditioners.
Effect of Inlet and Outlet Position on the Pumping Characteristics of a Diffuser/Nozzle Based Piezoelectric Micropumps
Jang, Hun-Hee ; Kim, Chang-Nyung ; Jung, Jin ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 19, issue 5, 2007, Pages 411~417
This study has been conducted to investigate pumping characteristics of diffuser/nozzle based piezoelectric micropumps. The micropumps include a piezo disk (an actuator), a chamber and a set of diffuser and nozzle. Flow in the current micropumps is controlled by a set of diffuser and nozzle, not by a nap valve. The diffuser/nozzle based micropumps are more reliable in operation and are easier in manufacturing than the flap valve based micropumps. The flow rates of the piezoelectric micropumps have been closely analyzed with a numerical calculation. It has been found that the positions of the inlet and outlet of the micropump can influence the performance of the diffuser/nozzle based piezoelectric micropumps. This study may provide fundamental understanding for the design and analysis of the piezoelectric micropumps.
Heat Transfer Characteristics depending on the Length of a Channel with Pin-Fin Array
Son, Young-Seok ; Shin, Jee-Young ; Lee, Sang-Rog ;
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 19, issue 5, 2007, Pages 418~425
The power consumption and heat generation in a chip increase as the components are miniaturized and the computing speed becomes faster. Therefore, suitable heat dissipation has become one of the primary limiting factors to ensure the guaranteed performance and reliable operation of the electronic devices. A pin-fin array which may be considered as a porous medium could be used as an alterative cooling system of the electronic equipment. The aim of the present study is to investigate the forced-convective heat transfer characteristics of pin-fin heat exchangers. Convective heat transfer through the pin~fin array is analyzed experimentally based on porous medium approach. The influence of the structure of the pin-fin array including the pin-fin spacing, the pin diameter and plate length on heat transfer characteristic is investigated and compared with the Previous analytical results and existing correlation equations. Nowadays, electronic and mechanical devices become smaller and smaller. In this sense, the main purpose of this study is to decide the optimum pin-fin arrangement to get similar heat transfer performance when the length of the existing cooling system is reduced as a half.