• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.3
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• pp.280-286
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• 2004

An experimental study is peformed to examine the heat transfer performance of individual rows of fin-tube heat exchangers. The heat transfer performance is measured using an air-enthalpy type calorimeter. The examined heat exchangers consist of 7mm tube and fin patterns of them are slit and louver types. Equivalent fin spacings are 18 fins per inch(fpi) for all samples, and the number of tube rows are two. In order to confirm that thermal boundary condition on fins of each row are the same, physically separated between two rows as well as connected heat exchangers are used. The frontal air velocity is varied from 0.7 to 2.5㎧. Heat transfer performance for each row is measured. It is observed that the heat transfer coefficient of the second row is smaller than that of the first row at low Reynolds number while larger at high Reynolds number.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.633-638
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• 2006

This study presents the air side heat transfer and friction characteristics of fin-tube heat exchangers with various fin types. A total of 8 samples of heat exchangers are tested. Fin patterns tested are slit, louver and plate fins. Each fin type has three cases of number of tube rows(N=1, 2, 3) and two different fin pitches. The results are plotted in terms of Colburn j-factor and friction factor f with respect to Reynolds number in the range of 200 to 510.

• Fire Science and Engineering
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• v.29 no.6
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• pp.1-5
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• 2015

In this study, the combustion characteristics of Hinoki Cypress Louver were measured after performing pressure impregnation with aqueous solution of boric acid, borax, and ammonium phosphate. The characteristics measured include ignition time, critical heat flux, and mass loss rate by incident hear flux (25, 30 and $50kW/m^2$). The samples used for the test were $100{\times}100{\times}10mm$, and the 5 min variation for each incident heat flux was measured 3 times. The results show that the ignition time for incident heat flux of $25kW/m^2$ showed a delay effect of 17.4 to 21.3% except for Type C-H. There was no significant difference at 35 and $50kW/m^2$ in the average mass loss rate in Types A-H and D-H, which had lower rates than Type N-H, which was predicted to be higher than that of Type N-H ($10.7kW/m^2$) by 38.22 to 60.46%. It is thus expected that at the time of initial primary fire, there would be a delay effect against fire spread.

• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.476-482
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• 2006

An experimental study has been performed to investigate the characteristics of air-side heat transfer and friction of a fined tube heat exchanger under heating conditions. Air enthalpy calorimeter was used to obtain the performance evaluation and analysis of the fined tube heat exchanger. Eight finned tube heat exchangers with slit fin, louver fin, and plain fin were used. The air-side heat transfer coefficient was calculated by the log-mean-temperature-difference. Air-side heat transfer and friction were presented in terms of j factor and friction factor on Reynolds number. From the experimental result, it was found that the variations of air-side heat transfer and friction of fined tube heat exchanger with the change of the fin configuration, row number, fin pitch, and tube circuit were obtained. j factor and friction factor decreased with Reynolds number increased. The tube circuit affected the air-side heat transfer and friction. In the case of slit and louver fin, j factor of 1st row was higher than that of 2nd row. But, with increasing Re, j factor was reversed. The characteristics of j factor and friction factor of 2nd row heat exchanger were different according to the kind of fins.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.538-545
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• 2020

The outdoor coal storage sheds of thermal power plants are being converted to indoor coal storage sheds worldwide because of the environmental pollution problems in the surrounding areas. On the other hand, indoor coal storage sheds are causing problems, such as indoor coal scattering and harmful gas generation. In this study, the ventilation method of indoor coal storage sheds was analyzed in terms of the internal flow characteristics and ventilation according to the outside wind velocity and direction. CFD analysis was performed based on the actual flow measurement information inside the indoor coal storage sheds. A comparison of the wind speed of 6 m/s and 2 m/s when the outside wind direction was easterly showed that the stream velocity to the monitor louver was faster and the recirculation area was clearer at 6 m/s than at 2 m/s. In addition, the trend of a westerly wind was similar to that of the easterly wind. The ventilation rate according to the wind speed was 13.1 times and 4.4 times for a wind speed of 6 m/s and 2 m/s, respectively. If the wind speed is 2 m/s, the situation does not meet the required number of ventilations per hour in a general plant, and needs to be improved.

• Korean Institute of Interior Design Journal
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• v.23 no.6
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• pp.14-21
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• 2014

Kengo Kuma is one of the features of the building is 'natural architecture'. He is saying that the construction of the building in which he is seeking is a natural material of construction is only applied to the issue as to whether the material nature, but that the relationship between humans, the environment, natural point of view in his book. Like repeating units are part of the two hundred ninety-four came mainly small ways to create a relationship, or have architectural features make up the sum of his architecture. I present a comprehensive study is reported in terms of that the 'grain' of such a small part of the unit, according to the architecture of Kengo Kuma mainly granulation characteristics of the construction of one of the practical expression studies Kengo Kuma. Is represented as louvers, check pattern, hole, granulation unit such trend, but have become developed in other directions such simple types are combined. Analysis and particle characteristics in terms of the architectural space of Kengo Kuma, serve as the purpose of the present study reveal that each of the features that have a meaning in the construction of any Kengo Kuma.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.1
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• pp.113-124
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• 1997

This work is performed to investigate the pressure drop and heat transfer characteristics in the air side of finned-tube heat exchanger for air conditioner. Experimental apparatus and method are described to simulate the heat exchanger performance by using the three times enlarged model. The pressure drop and heat transfer coefficient were measured and compared for the heat exchangers with a plane fin and a commercial strip fin. The measured data for the strip fin agree well with those of prototype within a few percentages. For the plane fin, the measured data had similar trend to Gray & Webb's correlation at high air velocity, however a new correlation is needed to give more accurate prediction at low air velocity. It is found that most heat was transferred around the front row of the two-row heat exchanger, and the ratio of thermal load at the front tube row was increased for decreasing air velocity.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.9 s.240
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• pp.1032-1041
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• 2005

This study is performed to investigate the heat transfer characteristics of heat exchanger according to the arrangement of fins as well as fin configuration by using the four times enlarged model. Friction factor, Colburn j factor and goodness factors are compared to each other to estimate performance of each case for 4 different kinds of fins, which are plain, single side slit, double side slit and louver fin. Results show that heat transfer would be altered by fin arrangement and that friction loss is more affected by fin configurations than by the fin arrangements. In particular, heat transfer depends more on the shape of front row than that of rear row. The heat transfer rate of combined fin arrangement increases a lot more under the same pressure drop than that of conventional fin arrangement. This indicates that the heat exchanger of higher efficiency would be designed by the proper combination of fins, of different shapes.

• Korean Institute of Interior Design Journal
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• v.13 no.2
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• pp.64-71
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• 2004

This study attempts to clarify inter-relationship between design expression in the surface of contemporary multi-family housing and physical trends in this digital age. The study examines characteristics of housing design influenced from new digital technology in the forms of metaphor such as dematerialization, fluidity and mobility. Currently constructed multi-family housing in Europe after 1990 has been analyzed to find digital reflections in the surfaces. As a conclusion, findings are as follows; In this digital age, a house is considered as a base in the forms of boxes and containers to network to outer worlds. In a complex of multi-family housing, public spaces move to the inside and become parts of private domain. Therefore, a house directly faces a street/outer world without transitional areas and devices. The facades of housing become delicate skins to control private domain in the inside and the world in the outside. In this digital age, the surfaces of housing are designed by ways of wrapping and screening. Printing and mapping methods are used to surface design because they are manipulative and flexible methods in design like graphic design. Screening devices using louvers and shutters are powerful tools to make random and unpredictable images. If units of a louver and a shutter were pixels, a whole surface would be a digital screen. In such assumption, the facade of buildings reflects digital screen to interface while the louvers in operation reflect clicking to network. As a conclusion, design expression in surfaces in-between of multi-family housing is a metaphor of digital mechanism.

• Journal of Plant Biotechnology
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• v.8 no.1
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• pp.1-8
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• 2006

The differential response of soybean cultivars with or without sulfur (S) application was observed under fold conditions. Plant biomass decreased by sulfur deficiency but the reduction was less in Bragg variety about 26 % relative to the control than other ones over 45%, probably due to less reduction in loaves and pods. The photosynthetic rate of Bragg cultivar was also unaffected by the absence of sulfur application while it depressed in other lines. Soybean cultivars were compared in terms of storage protein, protein quality and biomass production by application of sulfur nutrition. The storage protein concentration tended to decrease without sulfur application in all the cultivars, however the differential response of protein quality only by 11S/7S ratio to sulfur nutrition status was observed: For instance, Bragg cultivar had higher biomass and protein production but protein quality decreased at sulfur deficiency. On the other hand, biomass and protein production in other cultivars remained louver at sulfur deficiency but protein quality differed genetically in spite of sulfur nutrition status. These results suggest that the response of soybean to sulfur nutrition is controlled by genotypic difference and sulfur supply status.