• Journal of the Korean Solar Energy Society
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• v.33 no.2
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• pp.70-77
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• 2013

Recently the radiant panel heating and cooling system has been regarded as an alternative of low temperature heating and high temperature cooling by applying the renewable energy sources to the heating and cooling of buildings. Especially this system can be used as HVAC system alternatives in super high-rise buildings for energy saving and thermal comfort. Also it can be possible to reduce the plenum space because the minimum ventilation air will be supplied into the space. This study focused on the evaluation the basic characteristics of thermal output in prefabricated steel wall panel system for radiant heating and cooling. In order to evaluate the thermal output according to both various supply water temperatures and supply water flow rates, three-dimensional dynamic heat transfer analysis was performed. As results, for the heating mode, thermal output increased by 26% with the supply temperature increasing by $5^{\circ}C$. The surface temperature of panels range within $1{\sim}3^{\circ}C$. For the cooling mode, thermal output decreased by 18.2% with the supply temperature increasing by $2^{\circ}C$. The surface temperature of panels range within $0.5{\sim}1^{\circ}C$ and it was shown the even temperature distribution.

• Composites Research
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• v.37 no.5
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• pp.402-408
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• 2024

This study evaluates the mechanical performance and thermal analysis characteristics of adhesives exposed to harsh environments, including high temperatures, tap water, and salt water. Pull-out specimens were prepared to investigate changes in adhesive properties under varying temperature, moisture, and salinity conditions. Dynamic mechanical analysis (DMA) was used to measure the glass transition temperature, while field-emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS) were employed to assess microstructural and compositional changes. The results indicate that exposure to different environments induced post-curing, raising the glass transition temperature and enhancing the thermal stability and mechanical performance of the adhesives. Chemical analysis revealed Na and Cl ion penetration in specimens exposed to salt water, suggesting potential long-term degradation. Despite this, pull-out test results showed minimal variation in failure load across different environmental conditions, although microstructural deformation was observed on the adhesive surface after saltwater exposure. These findings provide valuable insights for selecting and applying adhesives in automotive and aerospace components exposed to harsh conditions.

• 한국태양에너지학회:학술대회논문집
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• 2008.04a
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• pp.324-329
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• 2008

Recently with the demand of well-being is increased, the demand for indoor thermal environment and air quality is increased. According to this circumstance, many people in Korea note the traditional architecture that is made by natural materials, such as a soil, stone and wood. However, few researches regarding the indoor thermal environmental characteristics of the Korean traditional houses is reported. In this study we analyzed the indoor thermal environment for Han-ok through field measurement. Moreover, based on the field measurement results. indoor thermal comfort in Han-ok is analyzed.

• Journal of Mechanical Science and Technology
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• v.15 no.11
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• pp.1482-1489
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• 2001

Thermally-induced errors originating from machine tool errors have received significant attention recently because high speed and precise machining is now the principal trend in manufacturing proce sses using CNC machine tools. Since the thermal error model is generally a function of temperature, the thermal error compensation system contains temperature sensors with the same number of temperature variables. The minimization of the number of variables in the thermal error model can affect the economical efficiency and the possibility of unexpected sensor fault in a error compensation system. This paper presents a thermal error model with minimum number of variables using a fuzzy logic strategy. The proposed method using a fuzzy logic strategy does not require any information about the characteristics of the plant contrary to numerical analysis techniques, but the developed thermal error model guarantees good prediction performance. The proposed modeling method can also be applied to any type of CNC machine tool if a combination of the possible input variables is determined because the error model parameters are only calculated mathematically-based on the number of temperature variables.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.193-198
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• 1996

In this study the RETRAN-03 code was modified to analyze the thermal-hydraulic transients under three-dimensional ship motions for the application to the future marine reactors. First Japanese nuclear ship MUTSU reactor have been analyzed under various ship motions to verify this code. As results, typical thermal-hydraulic characteristics of marine reactors such as flow rate oscillations and S/G water level oscillations are successfully simulated at various conditions.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.167-170
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• 2003

The thermal and hydraulic characteristics of the cooling passage for HTS power cable should be carefully investigated to get the highly reliable and economic operation. In this study, the pressure drop and temperature change of the coolant flowing the corrugated passage was estimated using the simple one-dimensional approach, and the temperature distribution in the radial direction was calculated. The results show the dependency of the mass flow rate, thermal conductivities on the cooling performance of the HTS cable.

• Journal of the Optical Society of Korea
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• v.17 no.2
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• pp.182-187
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• 2013

We present a comparative experimental analysis of the thermal spectroscopic characteristics of a phosphosilicate (P)-based ytterbium-doped fiber (YDF) against an aluminosilicate (Al)-based YDF in the temperature range of 25 to $150^{\circ}C$. We also characterize the fibers as gain media in a cladding-pumped amplifier configuration. While both fibers exhibit comparable trends in their thermal characteristics, there are noticeable distinctions in the fluorescence lifetime reduction rate and the spectral dependence of the transition cross-sections. The P- and Al-based YDFs present thermal lifetime reduction rates of $0.012%/^{\circ}C$ and $0.026%/^{\circ}C$, respectively. In particular, in the spectral region at ~940 nm, the absorption cross-section of the P-based YDF undergoes significantly less thermal change compared to that of the Al-YDF. In the cladding-pumped amplifier configuration operating at a total gain of 10 dB, the Al-based YDF generally performs betters than the P-based YDF in the temperature range of 25 to $75^{\circ}C$. However, it is highlighted that in the high temperature range of over $75^{\circ}C$, the latter shows a less gain reduction rate than the former, thereby yielding higher relative output power by 3.3% for a 1060-nm signal, for example.

• Journal of Environmental Impact Assessment
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• v.22 no.1
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• pp.19-26
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• 2013

The propose of this study is to analyze the optimum spatial resolution of the urban spatial thermal environment structure and to evaluate of the possibility detection using aerial photographs and thermal satellite images. The proper techniques of the optimum spatial resolution for the urban spatial thermal environment structure were analyzed. Thermal infrared satellite image of Seoul city were used for the change rate of surface temperature variation and suggested to the spatial extent and effects of urban surface characteristics and spatial data was interpreted as regions. To extract the surface temperature, Landsat thermal infrared satellite image compared with an automatic weather station data and in the field of the measured temperature and surface temperature by thermal environment affects, the spatial domain has been verified. The surface temperature of the satellite images to extract after adjusting surface temperature isotherms were constructed. The changes in surface temperature from 2008 to 2012 the average surface temperature observation images of changing areas were divided into space. The results of this study are as follows: Through analysis of satellite imagery, Seoul city surface temperature change due to extraction comfort indices were classified into four grades. The comfort index indicative of the temperature of Gangnam-gu, $23.7{\sim}27.2(^{\circ}C)$ range and Songpagu, a $22.7{\sim}30.6(^{\circ}C)$ respectively, the surface temperature of Yeouido $25.8{\sim}32.6(^{\circ}C)$ were in the range.

• Nuclear Engineering and Technology
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• v.41 no.3
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• pp.287-294
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• 2009

Due to thermal hydraulics phenomena, such as thermal stratification, various events occur to the parts of a nuclear power plant during their lifetimes: e.g. cracked and dislocated pipes and thermally fatigued, bent, and damaged supports. Due to the operational characteristics of the parts of the steam generator feedwater inlet horizontal pipe, thermal stratification takes place particularly frequently. However, the thermal stress due to thermal stratification at the steam generator feedwater inlet horizontal pipe was not reflected in the design stage of old plants(Kori Unit No.1, 2, 3 and 4, Yeonggwang Unit No. 1 and 2, and Uljin Unit No. 1 and 2; referred to as old-style power plants hereinafter). Accordingly, a verification experiment was performed for thermal stratification in the horizontal inlet nozzle steam generator of old-style plants. If thermal stratification occurred in the horizontal pipe of an old-style power plant, numerical analysis of the temperature distribution of the pipes and fluids was conducted. The temperature distributions were compared at the curved part of the pipe and the horizontal pipe before and after the installation of the improved thermal sleeves designed to alleviate thermal stress due to thermal stratification. The thermal stress reduction measure was proven effective at the steam generator inlet horizontal pipe and the curved part of the pipe.

• 한국전기화학회:학술대회논문집
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• 2001.10a
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• pp.30-30
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• 2001