• 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.18 no.4
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• pp.15-20
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• 2017

Currently, residential air conditioners operate as a heat pump during winter. In this case, the outdoor heat exchanger acts as an evaporator obtaining heat from cold air. On the other hand, it acts as a condenser during summer transferring heat to hot air. The outdoor temperature changes significantly from high to low. Generally, the air-side j and f factors are obtained at a standard outdoor temperature. Therefore, the applicability of the j and f factors under different outdoor conditions needs to be checked. In this study, tests were conducted for a two-row louver finned heat exchanger changing the outdoor temperature to subzero. The effects of the tube-side brine flow rate were also checked. The results showed that air-side j and f factors were essentially constant and independent of the outdoor temperature, suggesting that an extension of j and f factors obtained under standard conditions to a low outdoor temperature is acceptable. All j and f factors agreed within 9% and 3%, respectively. Tests were also conducted by changing the coolant flow rate. Both the j and f factors did not change according to the flow rate, suggesting that the tube-side heat transfer correlation is acceptable.

• Journal of Digital Convergence
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• v.19 no.9
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• pp.189-199
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• 2021

In order to increase the self-reliance rate of new and renewable energy in order to respond to the mandatory domestic zero-energy buildings, the taller the building, the more limited the site area, and installing PV modules on the roof is not enough. Therefore, BIPV (Building integrated photovoltaic, hereinafter BIPV) is the industry receiving the most attention as a core energy source that can realize zero-energy buildings. Therefore, this study conducted a survey on the problems of the BIPV industry in a self-discussing method for experts with more than 10 years of experience of designers, builders, product manufacturers, and maintainers in order to suggest the right direction and revitalize the BIPV industry. Industrial problems of BIPV adjustment are drawn extention range of standard and certification for products, range improvement for current small condition of various kind productions, need to revise standards for capable of accomodating roof-type, color-module and louver-module, necessary of barrier in flow of foreign modules into korea through domestic certification mandatory, difficulty in obtaining BIPV information, request to prevent confusion among participants by exact guidelime about architectural application part of BIPV, and lack of the BIPV definition clearness, support policy, etc. Based on the improvements needed for the elements, giving change and competitiveness impacts aims to present and propose counter measures and direction.