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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 15, Issue 12 - Dec 2003
Volume 15, Issue 11 - Nov 2003
Volume 15, Issue 10 - Oct 2003
Volume 15, Issue 9 - Sep 2003
Volume 15, Issue 8 - Aug 2003
Volume 15, Issue 7 - Jul 2003
Volume 15, Issue 6 - Jun 2003
Volume 15, Issue 5 - May 2003
Volume 15, Issue 4 - Apr 2003
Volume 15, Issue 3 - Mar 2003
Volume 15, Issue 2 - Feb 2003
Volume 15, Issue 1 - Jan 2003
Selecting the target year
Performance Test for High Efficient Heat Pump System using Seawater Heat Source and Exhaust Energy
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 12, 2003, Pages 979~986
The performance characteristics of heating and cooling operation for a heat pump system using seawater heat source and exhaust energy are presented. The heat pump system is made of a waste heat recovery system and a vapor compression refrigeration system. The working fluid is R-22. The heat pump system COPs are measured during heating and cooling operation modes, and the resultant COPs were 9.7 and 7.9, respectively, which are three times higher than those of the heat pump itself. Therefore, the performance of the heat pump system using exhaust energy is excellent compared to that of a general heat pump. The experimental data can be effectively used for the design of the high efficient heat pump using a seawater heat source.
Simulation on a Residential Heat Pump System Using
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 12, 2003, Pages 987~995
The performance of a residential heating and cooling system with
is predicted by using a cycle simulation model. The simulations are conducted by varying design parameters and operating conditions. The efficiency of the transcritical cycle can be improved by utilizing the advantages in heat transfer characteristics of
and developing microchannel indoor and outdoor heat exchangers. For the designed system of this study, the predicted COP of the heat pump system is approximately 3.5 in the heating mode and 3.0 in the cooling mode. The predicted optimal discharge pressure for the heat pump system is approximately 11 MPa in the heating mode and 9 MPa in the cooling mode.
Simulation of the Kitchen and Bathroom Exhaust Systems in High-Rise Apartment Buildings
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 12, 2003, Pages 996~1006
The objective of this study is to find major variables which influence the performance of kitchen and bathroom exhaust systems in high-rise apartment buildings. For this purpose, the influencing factors on the exhaust airflow rates from the kitchen or bathroom are identified and in every cases, which are made of combinations between the influencing factors, the exhaust airflow rates are calculated through the simulations. The results of the simulation show that the exhaust airflow rates from the kitchen and bathroom mainly depends on outdoor air temperature, number of floors, airtightness of the building envelope, fan on ratio, vertically connected to same shaft, exhaust fan capacity for kitchen or bathroom, roof ventilator capacity and shaft area for kitchen or bathroom exhaust.
Evaluation of Air-side Heat Transfer and Friction Characteristics on Design Conditions of Evaporator
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 12, 2003, Pages 1007~1017
An experimental study on the air-side pressure drop and heat transfer coefficient of slit fin-tube heat exchanger has been carried out. The data reduction methodology for air-side heat transfer coefficients in the literature is not based on a consistent approach. This paper focuses on new method of data reduction to obtain the air-side performance of fin-tube heat exchanger using R22 and recommends standard procedures for dry and wet surface heat transfer estimation in fin-tube heat exchanger having refrigerant on the tube-side. Results are presented as plots of friction f-factor and Colburn j -factor against Reynolds number based on the fin collar outside diameter and compared with previous studies. The data covers a range of refrigerant mass fluxes of 150∼250 kg/
s with air flows at velocity ranges from 0.3 m/s to 0.8 m/s.
A Numerical Study on the Performance Analysis of Plume Abatement Cooling Tower with Dry Type Heat Exchanger
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 12, 2003, Pages 1018~1027
This study treats the analysis of the performance and the design of plume abatement wet/dry cooling tower with dry type heat exchanger using a numerical method. A two-dimensional analysis is performed using the finite volume method for mechanical draft counterflow and crossflow tower. For a coupling problem between water and air system, a turbulent two phase flow is considered. Effectiveness-NTU method is used for modeling of the dry type heat exchanger. The parameter change simulations of the outer wall shape, the relative flowrate of air, and attachment of an air mixer are performed to examine the effect on plume abatement. It is found that if the relative air flowrate ratio and the adequate air mixer type are chosen well in addition to the ratio of water to air flowrate, the loss of the cooling capacity and the additional cost are reduced and the plume is abated.
Simulation and Cost Estimation of Energy Transportation at Ambient Temperature Using an Absorption System
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 12, 2003, Pages 1028~1034
The objectives of this paper are to study the effect of key parameters on the cycle performance and capacity and to estimate the cost of latent and sensible energy transportation systems. The overall conductance (UA) of each component, the ambient temperature and the absorber inlet temperature are considered the key parameters. It is concluded that COP of the solution transportation using an absorption system (STA) at ambient temperature is 10% higher than that of the conventional sensible system. It is also found that the cost of STA system can be reduced 7.5 times to that of sensible energy transportation for one year of operation with 10 km transportation distance.
A Study on the Evaluation of Heating-Conditioned Environment with the Size of Classroom - Focused on Inlet Temperature of Ceiling Type Air-Conditioning System -
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 12, 2003, Pages 1035~1042
As the desire for a better condition in classroom increases, the distribution rate of warming and cooling conditioners increases. But it is known that according to the way by which the equipments put and are operated the comfortableness felt by persons who are in classroom can make a difference. Therefore, proper equipments in accordance with the size of classroom should be considered as well as operational methods when ceiling warming and cooling conditioners put. This study makes conclusions as follows through a simulation to get improvements in accordance with the size of classroom and to improve the heating performance of ceiling warming and cooling conditioners in classroom.
The Effect of Non-uniform Superheat on the Performance of a Multi-path Evaporator
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 12, 2003, Pages 1043~1048
An experimental investigation was executed to determine the capacity degradation due to non-uniform refrigerant distribution in a multi-path evaporator. In addition, the possibility of recovering the capacity reduction by controlling the refrigerant distribution among refrigerant paths was assessed. The finned-tube evaporator, which had a three-path and three-depth-row, was tested by controlling inlet quality, exit pressure, and exit superheat for each refrigerant path. The capacity reduction due to superheat unbalance between each path was as much as 30%, even when the overall evaporator superheat was kept at a target value of 5.6
. It may indicate that the internal heat transfer within the evaporator assembly caused the partial capacity drop. For the evaporator having air mal-distributions, the maximum capacity reduction was found to be 8.7%. A 4.5% capacity recovery was obtained by controlling refrigerant distribution to obtain the target superheat at the outlet of each path.
Comparison of Condenser Characteristics using R410A and R22 under the Same Inlet Temperature Condition
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 12, 2003, Pages 1049~1059
R410A is considered as an alternative refrigerant to R22 for air conditioners. An experimental investigation was made to study the characteristics of the heat transfer and pressure drop for R410A flowing in a fin-and-tube heat exchanger used for commercial air-conditioning units. Experiments were carried out under the conditions of inlet refrigerant temperature of 6
and refrigerant mass flux varying from 150 to 250 kg/
s for refrigerant side. The inlet air has dry bulb temperature of 35
, relative humidity of 40% and air velocity varying from 0.68 to 1.6 m/s. Experiments show that air velocity decreased by 16% is needed for R410A than that of R22 for subcooling temperature of 5
, which resulted in air-side pressure drop decrease of 15% for R410A as compared to R22. As a consequence, in order to provide the same design condition of a condenser, the fan requires lower electric-power consumption with R410A than that with R22.
A Study on the Development of Information Database for Building Energy Retrofit using Remote Data Service (RDS) Technology
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 12, 2003, Pages 1060~1069
Our society becomes complex because technology is developing quickly. Especially, building services field deals with the important information that produces a drawing and manages the planning information and manpower. Therefore, the efficient management that connected with the construction information plays the important roles. The study develops a database by organizing systematically the various types of information using hypermedia. And, this study is to build the management system that can serve the various information that operated by DBMS on the web according to the DB structure. The information database was developed using internet web technology for building services field.
Analysis of Dynamic Humidity Control Characteristics of Museum Showcase with Adsorption Material
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 12, 2003, Pages 1070~1077
This study was undertaken to judge the quality of air-tightened exhibition cases and to predict the dynamic variation of the relative humidity in the showcase. We performed a lot of experiments for the a few conditions and we numerically calculated the air change rate and the relative humidity in the showcase with the Artsorb under the same conditions. In all cases we confirmed that the numerical results about the relative humidity in the showcase had a good agreement with the experimental ones. Through the experiments of humidity control, we found out that the adsorption efficiency is varied with the location and the amount of the Artsorb. And the numerical results showed that the adsorption material is always needed to keep on the appropriate humidity condition in the showcase even though any kind of the showcases are used.
A Numerical Study on the Flow and Heat Transfer Characteristics in a Kimchi Refrigerator
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 12, 2003, Pages 1078~1087
Kimchi refrigerator is a household electric appliance developed with the wholly domestic technology for maturing and keeping kimchi. However, the principle of keeping is not yet revealed obviously. This numerical study has been conducted to investigate the flow and heat transfer characteristics in a kimchi refrigerator. The effects of arrangement variation of a evaporation tube are examined. Also, the heat transfer characteristics through the insulation material are discussed in detail. The flow and temperature field was simulated using the commercial code of CFX-5.3. A natural convection flow is formed through about 5/6 region from the bottom within the keeping space and accordingly, the 90% region of kimchi containers satisfies the temperature requirement with 0
. The stagnant flow exists in the upper 1/6 region of the keeping space and accordingly, the stratified high temperature distributions appear in the upper region of kimchi containers. The upward shift of the start location of a evaporation tube improves the temperature concentration toward
but the pitch variation is of no effect. The heat fluxes on the insulation surfaces show two-dimensional distributions with being higher toward the center. Through the variation of insulation thickness, 3.5% saving of insulation material is obtained under the same heat transfer rate.
Model Development of Daily and Hourly Energy Load for Department Stores
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 12, 2003, Pages 1088~1094
Case study was peformed to analyze energy load for department stores and develop energy load model to be applied to a cogeneration system. Energy loads of 14 departments were analyzed based on energy load sheets written by operators and energy load of one department store was measured through modem communication for a year. Energy load of department stores shows various variations depending on when they are opened or closed and, hours, days and months. In this paper, the measurement was compared with data in energy load sheets and resolved, and energy load model for a department store was built. It is important to use an accurate energy load model for an accurate feasibility study applying a cogeneration system to buildings.
Study on Measurement and Numerical Analysis for Fluid Flow past a Circular Cylinder in Rectangular Duct
Korean Journal of Air-Conditioning and Refrigeration Engineering, volume 15, issue 12, 2003, Pages 1095~1102
Flow characteristics of turbulent steady fluid flow past a cylinder in rectangular duct are measured by 5 W laser doppler velocity meter. The fluid flow is also computed by commercial software of STAR-CD for comparison between the measurement and computation. The turbulent models applied in the computations are standard K-epsilon model, RNG K-epsilon model and Chen K-epsilon model. Acurracy of standard K-epsilon model is a little bit better than acurracies of other models even though those models have almost the same order of error compared to measured data. The computations predict satisfactorily the measured velocity profiles at middle section of the circular cylinder before the fluid flow diverges. However, there are some disagreements between them at down stream from the circular cylinder.