• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.10a
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• pp.192-193
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• 2008

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2007.10a
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• pp.224-225
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• 2007

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2007.10a
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• pp.427-428
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• 2007

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.7
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• pp.591-597
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• 2012

For the past few years, the concern for clean energy has been greatly increased. Ocean thermal Energy Conversion(OTEC) power plants are studied as a viable option for the supply of clean energy. In this study, we examined the thermodynamic performance of the OTEC power system for the production of electric power. Computer simulation programs were developed under the same condition and various working fluids for closed Rankine cycle, regenerative cycle, Kalina cycle, open cycle, and hybrid cycle. The results show that the regenerative cycle showed the best system efficiency. And then we examined the thermodynamic performance of regenerative cycle OTEC power system using the condenser effluent from Uljin nuclear power plant instead of the surface water. The highest system efficiency of the condition was 4.55% and the highest net power was 181 MW.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1993.05a
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• pp.47-52
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• 1993

Recently, as exactly clean source, the research of photovoltaic power generation is undertaken actively and widely. In this paper, an auxiliary power supply system which is composed of photovoltaic generation and DC-DC boost chopper is described. This system in mainly for Air-conditioner appliances is which AC source is formed through rectifying circuit and without electrical storage battery. There exist two operating modes depending on the power quantity of the solar cells and the load. The control algorithm is discussed.

• Particle and aerosol research
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• v.20 no.2
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• pp.69-77
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• 2024

In this study, the performance of air cleaners installed in subway stations was evaluated using field test method and chamber test method in accordance with the standard for air cleaner. Also, the air filter maintenance period was examined by the performance reduction of air cleaners with respect to the air filter usage period. From the field tests, the clean air delivery rate (CADR) of air cleaners with filter in use was about 85% on average compared to the ones with new filter. The main factor of CADR reduction was not the decrease of filter efficiency but the decrease of airflow rate. The chamber test results shows that the CADR of air cleaners decreased with the usage time, but the proper filter replacement can make the CADR keep about 95% of the certified CADR. The expected filter replacement cycle measured by the field test method was calculated to be approximately 3.35 months (100 days). However, the replacement cycle was a large difference between 1.2 and 6.6 months with the different stations. Therefore, the replacement cycle should be individually investigated for each station. The use of air cleaners must be effective in reducing fine dust in subway stations. For more effective air quality management in subway stations, additional researches is necessary to define the appropriate capacity of HVAC system and air cleaner, and related maintenance for each station.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.779-790
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• 1993

A prototype of the feeding-milking robot was developed in the Hungarian Institute of Agricultural Engineering in 1988-89. Before starting with the operation tests the cleaning system had to be elaborated . The cleaning system has two parts. Those are the complete cleaning of the system, producing a practically sterile state, as well as flushing through the milking device between milking of two cows. Separate electronic sensor development was necessary for both system which can connect to the control system of the robot. To clean the system pneumatic air input was applied. As an effect of the local adjustment of the electronic control system optimal flow conditions can be formed what is more favourable comparing to the earlier solutions of cleaning due to the mechanical effect. In the flushing through overpressure air is applied. The air and the cleaning liquid input duration can be adjusted to the local conditions. The electronic control unit can be connected to the electric ircuits of robot.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.9
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• pp.820-827
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• 2004

The propulsion force acting on a wafer in an air levitation system was measured accurately and then, the corresponding force coefficient was determined. The theoretical propulsion force on the wafer bottom surface were obtained by CFD simulations and from these results the propulsion force coefficient was deduced. The transportation velocity of a wafer was estimated by using both experimental and numerical force coefficients, for various air velocity of nozzle injection. When the numerical results are compared to the experimental data, the numerical results agree well Quantitatively.

• The KSFM Journal of Fluid Machinery
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• v.9 no.6 s.39
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• pp.45-53
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• 2006

Turbo-blower as an air supply system is one of the most important BOP (Balance of Plant) systems for FCV(Fuel Cell Vehicle). For generating and blowing compressed air, the motor of air blower consumes maximum 25% of net power, and fuel cell demands a clean air. In this study, turbo-blower supported by air foil bearings is introduced as the air supply system used by 80kW proton exchange membrane fuel systems. The turbo-blower is a turbo machine which operates at high speed, so air foil bearings suit their purpose as bearing elements. Analysis for confirming the stability and endurance is conducted. The rotordynamic stability was predicted using the numerical analysis of air foil bearings and it is verified through experimental works. In spite of various transient dynamic situation, the turbo-blower had stable performances. After the performance test, results are presented. The normal power of driving motor has about 1.6 kW with the 30,000 rpm operating range and the flow rate of air has maximum 160 SCFM. The test results show that the aerodymic performance and stability of turbo-blower are satisfied to the primary goals.

• Journal of Mechanical Science and Technology
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• v.17 no.11
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• pp.1801-1811
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• 2003

An experimental study was conducted to investigate the effects of air-side fouling and cleaning on the performances of various condenser coils used in unitary air-conditioning systems. A total of six condenser coils with different fin geometry and row number were tested. Performance tests were performed at three different conditions: clean-as-received, after fouling, and after cleaning. In all cases, it was observed that the fouling was mostly confined to the frontal face of the heat exchanger as reported in the previous investigations. The amount of deposited dust was more dependent on fin geometry for the single-row heat exchangers than for the double-row heat exchangers. The predominant effect of fouling was to cause a more significant increase in air-side pressure drop than a degradation in heat transfer performance. For the single-row heat exchangers, the pressure drop increased by 28 to 31%, while the heat transfer performance decreased by 7 to 12% at the standard air face velocity of 1.53 m/s depending on fin shape. For the double-row heat exchangers, the pressure drop increased by 22 to 37%, and heat transfer performance decreased by only 4-5% at the same air face velocity. Once the contaminated coils were cleaned according to the given cleaning procedure the original performance of the heat exchangers could almost be recovered completely. The pressure drop could be restored within 1 to 7% and the heat transfer performance could be recovered to within 1 to 5% of the originally clean heat exchangers. Therefore, it is concluded that a periodic application of the specified cleaning technique will be effective in maintaining the thermal performance of the condenser coils.