Search

Your search keyword '"Jang, Cheol-Yong"' showing total 40 results
Start Over Author "Jang, Cheol-Yong" Publication Year Range Last 50 years
40 results on '"Jang, Cheol-Yong"'

8. Thermal Performance Assessment of Insulated door by experiment

Author

Hong Won-Hwa, Jang Cheol-Yong, Ahn Byung-Lip, and Kim Chi-Hoon

Subjects
Glazing, Energy loss, Coating, business.industry, Thermal, engineering, Structural engineering, engineering.material, Air gap (plumbing), business, Central region, Building envelope, Thermal break
Abstract

Currently, Exterior wall`s U-value about building envelope is 0.36 W/(Central Region), but window`s one is 2.1 W/ according to air gap of glazing, filling gas, coating and type of windows. The door"s one is 1.6~5.5 W/ depending on material and configuration of door. As such, energy loss per unit of door is considerably larger like windows. The door for the recognition was relatively low because energy loss through the door is relatively small compared to window area. In this paper, thermal performance was analyzed through simulation targeting the door which has thermal break that can improve the insulation performance and doesn`t have one. As a results of simulations, case1 was calculated as the average of 1.63 w/m2k and case 2 was calculated as the average of 4.14 w/m2k. The thermal performance of door depends on the type and condition of insulations. As a results of final simulations, Case1 was calculated as 1.06 w/m2k and Case2 was calculated as 1.27 w/m2k. As a results of the experiments, thermal performance of case 1 was measured as 1.28 w/m2k. Error between experiments and simulations is considered problems encountered when creating the samples. The effect of door frame on the overall thermal performance is slight because it`s a small proportion of the door frame.

Published
2011

32. Window retrofit strategy for energy saving in existing residences with different thermal characteristics and window sizes.

Author

Ahn, Byung-Lip, Kim, Jong-Hun, Jang, Cheol-Yong, Leigh, Seung-Bok, and Jeong, Hakgeun

Subjects
RETROFITTING, ENERGY consumption, ENERGY conservation in buildings, THERMAL analysis, WINDOWS
Abstract

An adequate window system is one of the most important retrofit strategies for effective energy conservation of a building, because the U-value and solar heat gain coefficient of windows have enormous impact on the heating and cooling loads of buildings. Therefore, this paper presents methods for improving the energy efficiency of existing residences that have various window sizes and envelope insulations, through a window retrofit using optimal U-value and solar heat gain coefficient values. Furthermore, the window retrofit strategy has been standardized using analysis of the correlation between the properties of the retrofitted window and energy saving rates. The results show that the annual heating and cooling energy demand decreases by 7.9–16.7% when changing the U-value of the windows in a poorly insulated house, and that the relationship between the lower U-value and energy saving is strong for poorly insulated houses regardless of window size. However, for houses with better insulation and larger window sizes, the total energy usage decreases by 18.4–29.7% when the solar heat gain coefficient is lower, and the energy saving effect of the U-value decreases while that of the solar heat gain coefficient increases.Practical application: This study was focused on improving the energy efficiency of existing residences by applying retrofitting technology. By exploration of the contribution of the specific qualities of windows and the thermal envelope (insulation) system of buildings via simulation, it was determined that it is necessary to adjust the U-value and SHGC of retrofitted windows, in relation to the thermal performance and window-wall ratio of an existing residence, to achieve high energy efficiency. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

39. Mesoporous cellular foams supported Fe2.0SiW12O40: Synthesis, characterization and application to CO2 sorption

Author

Sharma, Pankaj, Park, Sang Do, Park, Ki Tae, Park, Jung Hoon, Jang, Cheol Yong, Nam, Sung Chan, and Baek, Il Hyun

Subjects
*MESOPOROUS materials, *CARBON dioxide adsorption, *IRON compound synthesis, *FOAM, *WETTING, *TRANSMISSION electron microscopy, *X-ray diffraction
Abstract

Abstract: Solid adsorbents comprising 50, 70, and 90wt.% heteropolyacid Fe2.0SiW12O40 (Fe–HPA) and mesoporous cellular foams (MCFs) have been synthesized by wetting impregnation. The adsorbents were characterized by various physicochemical, thermal and spectral techniques and the CO2 adsorption capacity of the adsorbents were investigated. The structure of Fe–HPA on the surface of the support was confirmed by TEM, SAXS, XRD, SEM, FTIR, 29Si MAS NMR, and XPS. XPS of the Fe 2p3/2, 2p1/2, 3p and W 4f7/2, 4f5/2, 4d5/2, 4d3/2 confirmed the presence of typical Fe(2+) and W(6+) in the adsorbent, respectively. The adsorbents showed a very high adsorption capacity due to the chemisorption of CO2. The CO2 adsorption capacity of a 70wt.% Fe–HPA–MCF sample was 111.8mg/g-adsorbent at 25°C. This result indicated that the reported iron (Fe2+) complex could be used as an efficient adsorbent for the separation of CO2. The adsorbents displayed excellent CO2 adsorption capacity and were thermally stable and recyclable. [Copyright &y& Elsevier]

Published
2013
Full Text
View/download PDF

40. A sensor-less LED dimming system based on daylight harvesting with BIPV systems.

Author

Yoo S, Kim J, Jang CY, and Jeong H

Abstract

Artificial lighting in office buildings typically requires 30% of the total energy consumption of the building, providing a substantial opportunity for energy savings. To reduce the energy consumed by indoor lighting, we propose a sensor-less light-emitting diode (LED) dimming system using daylight harvesting. In this study, we used light simulation software to quantify and visualize daylight, and analyzed the correlation between photovoltaic (PV) power generation and indoor illumination in an office with an integrated PV system. In addition, we calculated the distribution of daylight illumination into the office and dimming ratios for the individual control of LED lights. Also, we were able directly to use the electric power generated by PV system. As a result, power consumption for electric lighting was reduced by 40 - 70% depending on the season and the weather conditions. Thus, the dimming system proposed in this study can be used to control electric lighting to reduce energy use cost-effectively and simply.

Published
2014
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results