• KIEAE Journal
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• v.4 no.3
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• pp.87-94
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• 2004

The purpose of this study is to improve thermal environment of telecommunication equipment rooms that hold TDX-10, TDX-100, 5ESS-2000, PCM of the latest telecommunication equipment. Analysis program is used the commercial CFD code, Star-CD and DOE-2.1E. The result has been compared by the energy consumption and the temperature contour at the 1 m height of room for each case. Different methods such as the relocation of the existing air-conditioner, the inflow of the ambient air into room, the installation of the forced fan and the cooling system equipment of the duct-connection type have been used to test for improvement of thermal environment. The analysis shows that most efficient method is the inflow of the ambient air into room but auxiliary equipment should be needed to prevent the local thermal spot.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2002.05a
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• pp.173-179
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• 2002

There is a growing concert about energy efficiency at the present time. Even refrigerators can not be omitted from this issue. So the factors have been searched to decrease the consumption of electric power in refrigerators. It is possible to analyze the numerical data of the cover back machine and the change of condenser shape to find that they affect the consumption of electric powers by improving the fluid flow of within the interior of the refrigerator. As a result, the problems, fluid of the eddy and stationary of the existing refrigerator can be solved partly by the improved model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11b
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• pp.156-160
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• 2005

The radiated noise of the excavator is composed of the various noise sources such as the diesel engine, cooling fan and hydraulic system, so the noise reduction for each noise source is required. In this study, the source contribution analysis for these principal noise sources is performed by using the noise source removal method. And to reduce the noise due to each one, the various experiments and analyses are studied. On the basis of these results, the proper reduction countermeasures are derived to develop the excavator satisfied the $2^{nd}$ noise regulation of EU.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1461-1466
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• 2000

This paper investigates the noise reduction scheme in tractor cabin by using various steps of experiment. The experiments were performed in the field as well as in the lab to facilitate the detail test procedure. Some of the test results were compared with computational results. Several noise sources and paths were identified including the engine compartment (cooling fan and timing gear cover), hydraulic system and its components (hoses, tubes and there mount) and structural characteristics of the cab, window, mounting bracket and machine frame including steps. Throughout the several design changes, cab noise level was reduced from 80.2dBA to 74.8dBA.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.6-8
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• 2004

Recently, it is increasing to use more Brushless DC Motor with high energy density permanent magnet and semiconductor control unit for complementing the mechanical defect of Brushed DC Motors. For designing of BLDC Motors are required complex parameters like as rated characteristic, Geometries, B-H curve of magnet and steel materials, winding factor, etc. Moreover, design and manufacturing are difficult because of additional control circuits. Generally, Design parameters are gotten by analysis of Motor which is used. And the design parameters are used to design a new motor. But getting the design parameters through the eyes and experience is limited and it takes a long time. In this paper a method is proposed to efficiently analyze motor design parameters through the No load and Load Test, Back EMF Test, Simulation Analysis and Patent Analysis Method for existing BLDC Motor for a cooling Fan in Vehicle.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.261-265
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• 2003

As motor performance enhancement by improving electric design has reached its limit and downsizing issue has risen, the importance of thermal design is increasing. In this study, the flow and temperature distribution were reviewed with the help of CFD analysis and this result was compared with the experimental results. Furthermore, parametric analysis with thermal design structure showed that axial duct width but fan capacity is a critical factor to lower the hot spot temperature in electric motor.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.324-329
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• 2003

An air-conditioner has various noise sources such as cooling fan noise, pumping noise, flow noise and impact noise. Among these, impact noise is the most unpleasant source. This is because the noise is produced in indoor unit of air-conditioner. To control the noise source effectively, first we must identify the noise sources. When we identify impact noise source, the measurement have to be carried out simultaneously. So we use beamforming method that requires less measurement points than intensity method and acoustic holography. The objective of this paper is to estimate the location of impact source. This objective can be achieved by using minimum variance cepstrum that is able to detect impulse embedded in noise. In this study, modified beamforming method based on cepstrum domain is proposed. Then this method applied to air-conditioner noise sources which produce impact noise.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.316-319
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• 2002

Injection mold is a manufacturing process used to produce parts of complicated shape at a low cost. Many factors affect the quality of injection molded part during injection molding process. A study on the optimization of injection mold is progressed by using a simulation software like Moldflow. Filling, packing and cooling phases of injection molding processes are analyzed according to the mold design considering the shrinkage of molded part, the degree of filling rate and the wearing of a mold. Taguchi method is applied to analyze the significance of processing parameters and the dynamic characteristics according to the variation of processing parameters. From the results, the mold temperature and packing pressure influenced strongly the shrinkage of injection molded part.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.3
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• pp.243-249
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• 2005

The present study has been conducted to simulate dynamics of a gas engine-driven heat pump(GHP) for design of control algorithm. The dynamic modeling of a GHP was based on conservation laws of mass and energy. For automatic control of refrigerant pressures, actuators such as engine speed, outdoor fan, coolant three-way valves and liquid injection valve were PI or P controlled. The simulation results showed physical behavior that is realistic enough to apply for control algorithm design.

• International Journal of Air-Conditioning and Refrigeration
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• v.6
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• pp.1-13
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• 1998

The basic heat transfer process that occurs in a building can best be illustrated by an electrical circuit network. Present paper reports the dynamic simulation of annual energy consumption in an office building by the thermal resistance capacitance network method. Unsteady thermal behaviors and annual energy consumption in an office building were examined in detail by solving the simultaneous circuit equations of thermal network. The results are used to evaluate the accuracy of the modified BIN method for the energy consumption analysis of a large building. Present thermal resistance-capacitance method predicts annual energy consumption of an office building with the same accuracy as that of response factor method. However, the modified BIN method gives 15% lower annual heating load and 25% lower cooling load than those from the present method. Equipment annual energy consumptions for fan, boiler and chiller in the HVAC system are also calculated for various control systems as CAV, VAV, FCU+VAV and FCU+CAV. FCU+CAV system appears to consume minimum annual energy among them.