• Journal of Korean Society for Atmospheric Environment
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• v.12 no.1
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• pp.43-53
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• 1996

Numerical simulation was performed for the 3-dimensional flow filed of gas and particle phase for cyclone dust collector. FVM(Finite Volume Method) was employed for gas phase. The flow was solved suing the k-.varepsilon. epsilon turbulence model. The particle exit at the bottom of the cone was treated as a solid wall in this model because the gas flow through the effective dust exit is usually insignificant. The major parameters considered in this study was vortex finder diameter, effective dust exit diameterm vortex finder length, inlet type for dimension performance. Particle trajectory calculations were made for three different, particle sizes of 1, 25 and 50 .mu.m. The results obtained from this study give some physical insight of dust particle collection mechanism together with the indication of the collection efficiency. The simulation results were in generally good agreement with empirical knowledge. The application of this kind of computer program looks promising as a potential tool for the design of cyclone and determination of optimum operating condition.

• Journal of the Korean Professional Engineers Association
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• v.42 no.6
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• pp.47-52
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• 2009

According to increasing demand of water mainly due to the growth of population and increased water consumption, many countries either face or worry about the shortage of fresh water. Proportionately, importance and efforts of each country to develop the potable water has been gradually increasing as well. Among others, desalination of seawater has been developed to one of the solutions mainly from the middle east and other arid regions to produce large quantity of fresh water from seawater. We installed beach seawater collector wells to develop the filtered seawater supply for desalination in a refinery. We came to a conclusion that the beach seawater collector well is one of the recommendable alternatives of seawater pre-treatment for desalination applications with lower operating cost and higher efficiency.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.11
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• pp.805-811
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• 2010

A numerical study has been performed to investigate the thermal performance of solar heating system with baffle type of storage tank by using the commercial code TRNSYS. As a result, the solar fraction depends strongly on the efficiency and heat loss coefficient of solar collector as well as the heating capacity of house and the water temperature supplied to the shower. In addition, the solar fraction has been basically ranked to higher level in baffle type of storage tank than typical type of single storage tank for the range of operation condition.

• Journal of Energy Engineering
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• v.22 no.3
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• pp.302-306
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• 2013

A simple method for balancing flow rates in arrays of parallel connected flat plate solar collectors has been developed. The method is based on a computer program which solves for the flow rate through each of the collectors in a reverse return plumbed array. The analysis uses conventional "K-value" techniques and assumes the effects of density variations within the system to to be negligible. It has been found that by appropriately sizing the inlet and outlet manifolds, flow maldistribution can be nearly eliminated without resorting to expensive or complicated balancing techniques.

• Nuclear Engineering and Technology
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• v.15 no.2
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• pp.149-153
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• 1983

The removal of zinc (II) from aqueous solutions has been studied by the adsorptive bubble separation processes such as solvent sublation and foam fractionation processes using capric acid as collector. The efficiency of the remoal process has been studied by changing the ionic strength and pH and the bubble separation method has been compared with the solvent extraction process using the capric acid dissolved in benzene as extractant.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.1
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• pp.58-66
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• 2019

Static compound parabolic collectors (CPCs) have advantages such as ease for fabrication and lower cost compared with other concentrating collectors. In this study, thermal performance analysis of CPC employing heat storage tank was carried out. The clearness index and capacity of heat storage tank are taken as the main parameters for numerical simulation. The effects of the parameters on the hourly and daily system performances ncluding the useful energy, heat loss, and collector efficiency were numerically investigated. Results showed that the system has a potential for efficient recovery of solar thermal energy.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.14 no.1
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• pp.1-11
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• 1985

Solar/absorption cooling system was analyzed and its operating condition was examined. For the system, the optimum size of absorption refrigerator and collector area should be determined. As the temperature of water supplied to the generator increases, the collector efficiency decreases whereas the coefficient of performance of absorption refrigerator increases up to a certain point, and vice versa for decreasing of the temperature of water supplied to the generator . Thus if the reeling load is given, the appropriate operating condition can be determined between the two opposing trends by simulation program. As an example of the simulation, the case of Jejudo province was studied. Under the conditions (such as weather data and prices of components, etc.) given en the sample calculation, the result shows that the optimum temperature of water supplied to the generator turned out to be $80.3^{\circ}C$, and still shows a large economical disadvantage in present stage compared to the case of conventional vapor compression cooling/heating combined heat pump system.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.4
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• pp.274-280
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• 2007

This paper demonstrates an efficiency improvement of the class E power amplifier (PA) by tuning-out the input capacitance ($C_{IN}$) of the power HBT with a shunt inductance. In order to obtain high output power, the PA needs the large emitter size of a transistor. The larger the emitter size, the higher the parasitic capacitance. The parasitic $C_{IN}$ affects the distortion of the voltage signal at the base node and changes the duty cycle to decrease the PA's efficiency. Adopting the L-C resonance, we obtain a remarkable efficiency improvement of as much as 7%. This PA exhibits output power of 29 dBm and collector efficiency of 71% at 1.9 GHz.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.1
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• pp.34-38
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• 1999

In order to develop a thin type ESP(Electrostatic Precipitator) for high efficient air-conditioner with low concentration of ozone generation, collecting electrode spacing should be narrower than that from Deutsch formula and minimizes discharge current in ionizer. In this paper, the effect of applied voltage on the precipitation efficiency and ozone concentration of scroll type ESP was studied. As a result, precipitation efficiency(one pass) was improved by about 30[%] from increment of collector voltage(3.5[㎸]). Precipitation efficiency was increased with increasing ionizer voltage. And after some point, the efficiency was saturated. At the point, voltage and ionizer current was 5.2[㎸] and 95$[\muA]$ per meter respectively. At these applied voltage conditions, ozone concentration was saturated about 0.01[ppm] after 3 hours in 23$[m^3]$ closed room test.

• Journal of Animal Environmental Science
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• v.13 no.2
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• pp.97-104
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• 2007

This study was carried out to develop the modified cyclone dust collector in windowless broiler building measuring 12 m wide, 46 m long, with a side wall height of 3 m and a capacity of 12,800 birds. Ventilation rate in windowless broiler building was $0.014{\sim}0.015\;and\;0.158{\sim}0.181cmm$ in second weeks and fifth weeks of age, respectively. Ammonia concentration was $13{\sim}16\;and\;20{\sim}24\;ppm$ in first and second weeks of age, respectively. Amount of dust collected in dust collector each week was 104.1, 274.7 and 388.6g in first, second and third weeks of age. But it was decreased from fourth weeks of age because of the increased ventilation rate. Total suspended particulate(TSP) of polluted air was $3,111.7{\sim}8,745.2{\mu}g/m^3$, but it was decreased to $530.8{\sim}2,264.4{\mu}g/m^3$ when it passed through the dust collector. Collecting efficiency was $54.2{\sim}82.9%$ in TSP. But collecting efficiency of Particulate matter smaller than $1{\mu}g$ (PM1.0) was $7.6{\sim}33.8%$, and lower than TSP. TSP concentration in control broiler house was 1,387.6 and $4,210.1{\mu}g/m^3$ in first and fourth weeks of age, respectively. But it was decreased to 876.3 and $2,535.3{\mu}g/m^3$ in broiler house operated dust collector in first and fourth weeks of age, respectively. Dust collecting efficiency for TSP was $36.8{\sim}39.8%$, and it was decreased to $11.4{\sim}39.8%$ in smaller dust size.