• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.6
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• pp.53-59
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• 2010

This research aims in finding a more optimal ejector size for evacuating engine exhaust gasses and 20% of the cell cooling air. The remaining 80% of cell cooling air pumped into the test chamber is separately exhausted from the test chamber via a discharge port fitted with flow control valves and vacuum pump. Unlike its predecessor this configuration utilizes a smaller capture area to improve pressure recovery. The modified ejector size has a diameter of 1100mm enough to evacuate 66kg/s jet engine exhaust in addition to about 20%, 24kg/s of the cell cooling air tapped from the sterling chamber. This configurations has an area ratio of the engine exit and ejector inlet of about 1.2. Simulation results of the proposed ejector configuration, indicates improved pressure recovery.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.11
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• pp.873-879
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• 2014

In the present study, water vapor is injected at various positions in a Clean Dry Air (CDA) system such as a system inlet duct, compressor inlet, and compressor outlet by humidified air turbines. The application of evaporative cooling reduces the compression work and enhances the Energy Consumption Index (ECI) per unit volume. The main purpose of this study is to investigate the compressor power performance with different inlet air temperatures and humidity conditions. It is found that the actual power consumption and discharge flow are significantly influenced by the inlet air temperature as well as relative humidity. The results obtained during this study are compared both numerically and experimentally and are found to be in very good agreement.

• Solar Energy
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• v.2 no.2
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• pp.29-36
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• 1982

The Solar Energy R&D Department of KIER under the auspice of the Korean government is pushing hard on the development of the passive solar technology with high priority for the expeditious widespread use of solar energy in Korea, since the past few years of experiences told us that the active solar technology is not yet ready for massive commercialization in Korea. KIER has completed the construction of the Solar Energy Research & Test Center in Seoul, which houses the major facilities for its all solar test programs. The Center was designed as a passive solar building with great emphasis on the energy conserving ideas. The Center is not only the largest passive building in Korea, but also the exhibit center for the effective demonstration of the passive heating and cooling technology to the Korean public. The Center was designed to satisfy the requirements based on the technical and economical criteria set by the KIER. Careful considerations, therefore, were given in depth in the following areas to meet the requirements. 1) Passive Heating Concepts The Center employed the combination of direct and indirect gain system. The shape of the Center is Balcomb House style, and it included a large built-in sunspace in front. A partition, consists of transparent and translucent glazings, separates the sunspace and the living space. Since most activities in the Center occur during the day time, direct utilization of the solar energy by the living spaces was emphasized with the limited energy storage capacity. 2) Passive Cooling Concepts(for Summer) Natural ventilation concept was utilized throughout the building. In the direct gain portion of the system, the front glazing can be openable during the cooling season. Natural convection scheme was also applied to the front sunspace for the Summer cooling. Reflective surfaces and curtains were utilized wherever needed. 3) Auxiliary Heat ing and Cooling System As an auxiliary cooling system, mechanical means(forced convection system) were adopted. Therefore forced air heating system was also used to match the duct work requirements of the auxiliary cool ing system. 4) Effect ive Insulation & Others These included the double glazed windows, the double entry doors, the night glazing insulation, the front glazing-frame insulation as well as the building skin insulation. All locally available construction materials were used, and natural lightings were provided as much as possible. The expected annual energy savings (compared to the non-insulated conventional building)of the Center was estimated to be about 80%, which accounts for both the energy conservation and the solar energy source. The Center is being instumented for the actual performance tests. The experimental results of the simplified tests are discussed in this paper.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.647-653
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• 2000

In this research the heat regenerative technology was employed to eliminate frosting on evaporator coil and improve COP of the heat pump system. This heat regenerative device(HRD) has very simple structure consisting a geared motor and a porous fiber belt passing through alternatively between cold and warm air duct. The laboratory test showed that the heat pump system with HRD yielded an impressive COP higher than 3.5 at the outside air temperature of $-7^{circ}C$ in heating mode.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.926-927
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• 2011

In this paper, temperature distribution of 24 MVA distribution cast-resin transformers is analyzed by using CFD. Usually heat generated in transformer causes many problems. To radiate the heat, conduction and convection are done through the duct between winding. Considering natural convection, fluid analysis is applied to the fluid region surrounding the transformer. As a result of the analysis, hot spot temperature point is predicted at the low-voltage winding. Through this paper, heat distribution and cooling characteristics property can be predicted by analyzing transformer heating characteristic required when designing.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.780-782
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• 2001

The mold transformer has anti-burnt and possibility of small size contrary to oil-immersed transformer. The mold transformer has generally cooling duct between low voltage coil and high voltage coil and also made by one body molding for small size and low loss. In this paper, the temperature distribution of designed 50kVA pole mold transformer for power distribution is investigated by FEM program. The designed transformer is also manufactured and temperature rise test is carried out.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.3
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• pp.193-200
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• 2009

The ventilation system of apartments can be divided by supply and exhaust fan, supply fan and exhaust free and supply free and exhaust fan. Recently, the individual ventilation system and central ventilation system which is combined cooling system with duct system are applied to apartment ventilation system. The airflow pattern is affected by location of supply unit and exhaust unit in indoor. This study is to investigate the proper distance between supply unit and exhaust unit using CFD. As a result of this study, the proper distance between supply unit and exhaust unit could be suggested at the interval of 3 m in supply and exhaust fan system and 2.5 m in supply fan and exhaust free.

• 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 KIEE Conference
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• 1995.11a
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• pp.24-26
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• 1995

The Development of A.C. Induction Motor for Railway Rolling Stock. The traction motor is designed as 4-pole induction motor with self ventilation. The winding insulation is throughout of materials of class C. The rotor is designed as a squrrel rotor with copper bar and casting. The rotor speed is detected by means of a pulse generator. The newer tection motor have no casting(frame). Punched-in holes make up the air duct and transfer the heat losses in complete. Maximim motor rpm is higher due to rotor construction. New is the entry of water-cooled traction motors in urban, However the water cooling design in - unfortunately - not applicable in traction motor.

• 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.