• International journal of advanced smart convergence
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• v.9 no.2
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• pp.123-128
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• 2020

We constructed a cooling system for solar cells using convection phenomena and investigated its cooling performance. The cooling system didn't need any driving power or water resources. The convection cooler manufactured with a right-triangle shape of an air duct was attached to the rear of the solar cell to confirm that cooling was performed using convection phenomena. When the ratio of duct width to attachment surface width was 3:7, and the ratio of entrance height and exit height of duct was 5:1, it showed the best cooling performance. Comparative experiments with solar cells without convection cooler showed that cooling effects from 16.5℃ to 20.9℃ occurred after 40 minutes exposed to the 1300W Xenon lamp condition.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.1136-1145
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• 1996

This study was to develop the most effective cooling system which is needed to cool greenhouse during summer night to get early blooming of strawberries. Various cooling systems were designed and constructed to utilize the cool air and water from tan abandoned coal mine. Cooling systems built for this study were an evaporative cooling system with pad, cooling system using a small or large radiator , and duct cooling system using cool are drawn from coal mine. These systems were individual tested to investigate their effects on cooling greenhouse during summer night. Also, a combined cooling system was tested with operating an evaporative cooling system, small radiator, and duct cooling system simultaneously. The results in this study showed that individual cooling systems such as evaporative cooling system, small radiator, and cooling duct had about the same effect on cooling greenhouse. The combined system had little better cooling effect than that of individual cooling syst m except the large radiator . The most effective system for cooling of greenhouse was obtained with using a large a large radiator as the heat exchanger. With operating a large radiator, temperature inside the greenhouse was dropped to about 15-16$^{\circ}C$ while outside temperature was 23-24$^{\circ}C$ during summer night.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1330-1335
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• 2007

The HVAC and the air duct is to make optimal indoor environment. By the HVAC position, method and the air duct construction, the important elements can affect on cooling performance, passengers' convenience, and energy efficiency. According to this, there are features, such as the indoor temperature distribution, cooling performance, velocity distribution from diffuser, tend to be come out variously. Also, comparing and analysing temperature distribution, cooling performance, air velocity, noise based on the real practical vehicle tests, it shows features in detail. Besides, it can lead to make design the system of HVAC & air duct effectively.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.1
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• pp.42-48
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• 2005

Because Impinging jet has excellent heat & mass transfer characteristics. it has many advantages of cooling. drying. etc and widely applied at industrial fields. Therefore, there have been many experimental investigations and theoretical studies about Impinging jet. The present study is about a cooling characteristic by Impinging jet for a Square Plate on Duct and investigated this characteristic through three-dimensions numerical analysis, using FLUENT. As the result of this study, heat transfer effect is the most appropriate condition when the ratio of distance is 6 between nozzle exit diameter and heat source. diameter of duct is 90mm and height of duct is 60mm. In addition. under the influence of injected jet. stagnant fluid flow into free jet field and this affected the whole flow field. So the shape of duct is a important factor and the researcher confirmed the need of investigation about duct.

• The KSFM Journal of Fluid Machinery
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• v.12 no.2
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• pp.24-30
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• 2009

Flow and noise analyses are conducted for examining a new design concept of impinging jet electronics cooling, and the analysis results are compared with conventional electronics cooling techniques. For the application of impinging jet electronics cooling method, the present study considers the air duct where air is supplied by axial fan and air flow from the duct is impinged vertically onto the electronic component heat source. Applying CFD simulation technique and fan noise model to the present cooling scheme, the cooling performance of the impinging jet as well as the operation condition and the noise characteristics of fan are investigated for various impinging jet nozzle conditions and fan models. Furthermore, the impinging jet electronics cooling analysis results are compared with the conventional parallel-flow cooling scheme to give the design concept and criteria of impinging jet cooling method.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.405-409
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• 2001

An experimental analysis of the flow inside the refrigeration compartment of a home refrigerator was conducted in order to achieve better performances in terms of uniform temperature distribution and cooling speed. 2D PIV and stereoscopic PIV were used for the experiments on an actual-size refrigerator at operating conditions. Two CCD cameras were employed for a wider field of view in the measurement of the shelf, and stereoscopic PIV was used to measure the three velocity components at the various cooling duct outlets and the mean velocity fields were area-integrated to calculate the flow-rates. 50 to 100 instantaneous velocity fields were time averaged for the mean velocity fields. With the result of this analysis, a new cooling duct system was developed, with the refrigerator's cooling performance increasing 11% in terms of cooling speed, and 25% in temperature uniformity.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1253-1257
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• 2004

We have developed new rear LCD Projection TV engine with 3 projection lens. It has high brightness and contrast ratio, however poor cooling conditions. If optical components close to light source, optical components are damaged on high temperature, especially the blue among RGB colors is weakest by heat In this study, a new enhanced cooling method of LCD projection TV with 3 lens is shown: the best suited design of duct and relations between LCD panel and polarizer lifetime with changed area of duct.

• Korean Journal of Environmental Agriculture
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• v.15 no.2
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• pp.223-231
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• 1996

This study was to develop the most effective cooling system which is needed to cool greenhouse during summer night for getting up early blooming of strawberry. Various cooling systems were designed and constructed to use cool air and water from an abandoned coal mine. Cooling systems built for this study included an evaporative cooling system with cooling pad, heat exchanger using small or large radiator, and cooling duct for drawing cool air from coal mine. The cooling pad, small or large radiator and cooling duct were individually tested. Also, combined cooling system was tested by operating cooling pad, small radiator, and cooling duct simultaneously. The results in this study showed that individual cooling systems such as cooling pad, small radiator, and cooling duct had about the same effect on cooling greenhouse. The combined cooling system had little better cooling effect than individual cooling system except the large radiator. The most effective cooling system for cooling of greenhouse was obtained by using a large radiator as the heat exchanger. By using a large radiator, temperature in greenhouse was dropped into about $15^{\circ}C$ when outside temperature was $23-24^{\circ}C$ during summer night.

• Aerospace Engineering and Technology
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• v.9 no.2
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• pp.193-197
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• 2010

Water cooling ducts are installed in the exhaust diffuser for high altitude tests of rocket engine to protect diffuser from high-temperature combustion gas. The mass flow rate and pressure of cooling water is designed to prevent boiling of cooling water in the ducts. Therefore, the estimation of maximum temperature of duct wall is important parameter in design of cooling system, especially pressure of cooling water. The method for predicting maximum temperatures of duct walls with variation of coolant flow rates was derived theoretically.

• The KSFM Journal of Fluid Machinery
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• v.4 no.3 s.12
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• pp.7-13
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• 2001

The present study investigates convective heat/mass transfer and flow characteristics inside a cooling passage of rotating gas-turbine blades. The rotating duct has staggered ribs with $70^{\circ}$ attack angle, which are attached on leading and trailing surfaces. Naphthalene sublimation technique is employed to determine detailed local heat transfer coefficients using the heat and mass transfer analogy. Additional numerical calculations are conducted to analyze the flow patterns in the cooling passage. The present experiments employ two-surface heating conditions in the rotating duct because the exposed surfaces to hot gas stream are pressure and suction side surfaces in the middle passages of an actual gas-turbine blade. Secondary flows are generated by Coriolis and centrifugal forces in the spanwise and streamwise directions. The ribs attached on the walls disturb the mainflow resulting in recirculation and secondary flows near the ribbed wall. The local heat transfer and flow patterns in the passage are changed significantly according to rib configurations and duct rotation speeds. Therefore, the geometry and arrangement of the ribs are important for the advantageous cooling performance. The experimental results show that the ribs enhance the heat transfer more than $70\%$ from that of the smooth duct. The duct rotation generates the heat transfer discrepancy between the leading and trailing walls due to the secondary flows induced by the Coriolis force. The overal heat transfer pattern on the leading and trailing walls for the first and second passes are depended on the rotating speed, but the local heat transfer trend is affected mainly by the rib arrangements.