• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.172.2-172.2
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• 2010

This study was carried out in order to reduce the installation expense of heating system for greenhouse comparing to geothermal heat pump and develope the coefficient of performance (COP) for a heat pump. For getting plenty of heat flux from geothermal energy. Surface water in river channel was used for getting a lots of geothermal heat by penetrating water through underground soil layer of the river bank that make heat transmission to passing water. The range of water temperature after the process of Ground filtration is 13~18 degrees celsius which is very similar to low heat source of geothermal heat pump system and the plenty amount of heat source from that make the number of geothermal heat exchanging hole and the expense for geothermal heat exchanger construction reduced. Drainage well is also used for returning filtration water to the aquifer that keep the water good recirculation from losing geothermal heat and water resource. For the COP improvement of Heat pump, thermal storage tank with separating insulation plate according to the temperature difference make the COP of Heat pump that is similar to thermal storage tank with diffuser. Developed thermal storage tank make construction expense cheaper than customarily used one's. and that sand filter and oxidation sand (FELOX) are going to be used for improving ground filtration water quality that make heat exchanger efficiency better. All above developed component skill are going to be set on the Ground filtration water source heat pump system and applied for medium, large scale for protected greenhouse in riverside area and on-site experiment is going to do for optimizing the heating system function and overcome the problem happening in the process of on-site application afterward.

• Journal of Welding and Joining
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• v.25 no.2
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• pp.43-48
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• 2007

Laser Transmission Joining (LTJ) of plastics is a process in which light of suitable wavelength is transmitted through a transparent substrate that is in contact with an absorbing one. In this paper, LTJ is investigated by preliminary experiments from the viewpoint of mechanical engineering. To understand transmitting characteristics of each polymer substrate, transmission rate, reflection rate and absorption coefficient of polymer are measured by using a laser power-meter. Characteristics of joining in the spot welding and seam welding are investigated by measuring the fracture load. Fracture load increases in accordance to the laser power and irradiation time. However, when the laser power is over 60W and irradiation time over 4seconds, fracture load decreases. This phenomenon is probably due to heat-softening of materials. Besides, cavities are generated at a joint by evaporation of water molecules, which can be suppressed by introduction of a gap between two substrates.

• Journal of the Korean Institute of Rural Architecture
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• v.20 no.1
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• pp.11-18
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• 2018

The study aims to address the energy crisis and realize self-sufficiency of building as part of local energy independence, breaking away from a single concentrated energy supply system. It is intended to develop modules of the outside insulation composite panels that conform to passive certification criteria and for site-assembly systematization. The method of study first identifies trends and passive house in literature and advanced research. Second, the target performance for development is set, and the structural material is selected and designed to simulate performance. Third, a test specimen of the passive outside insulation curtain wall module designed is manufactured and constructed to test its heat transmission coefficient, condensation performance and airtightness. Finally, analyze performance test results, and explore and propose ways to improve the estimation and improvement of incomplete causes to achieve the goal. The final test results achieved the target performance of condensation and airtightness, and the heat transmission coefficient was $0.16W/(m^2{\cdot}K)$, which is $0.01W/(m^2{\cdot})K$ below the performance target. As for the lack of performance, we saw a need for a complementary design to account for simulation errors. It also provided an opportunity to recognize that insulated walls with performance can impact performance at small break. Thus, to be commercialized into a product with the need for improvement in the design of the joint parts, a management system is needed to increase the precision in the fabrication process.

• Journal of Energy Engineering
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• v.22 no.2
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• pp.83-89
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• 2013

Energy consumption is closely related to our lives. As Korea has four seasons, heating and cooling system is considered as essential facilities for the residential buildings. Accordingly, the government has continuously strengthened the design criteria to improve energy for new and existing building to save energy. The most important factor in the energy efficiency analysis for apartment is the heat transmission coefficient, and the value is significantly different as the heating energy amount is greatly different according to the window area ratio versus facade area ratio. Therefore, it is time to conduct continuous set-up for goal to enhance efficiency and restriction on window area ratio versus facade area ratio.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.6
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• pp.1021-1030
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• 1997

Physical variables related to the subjective evaluation of wear comfort were explored. Experimental fabrics was those used in the previous paper where subjective sensations of women's thin shirts were reported. Fabrics include 100% cotton (unfinished), 100% cotton (water repellent finished), cotton/polyester 35/65 (unfinished), cotton/polyester 35/65 (peach skin finished), 100% polyester fabric(plain), 100% polyester crepe. Among various physical properties of the experimental fabrics, heat 8E moisture transport properties and surface properties were chosen as important variables based on the regression coefficient. Especially, humidity at the microclimate in dynamic mode was highly correlated to the subjective evaluation and appeared to be a sensitive physical predictor, compared to dry thermal transmission rate or water vapor transmission rate. Surface characteristic parameters, however, did not show consistant trend in the prediction of the human's subjective sensation. Interaction between surface properties and humidity measurement was also observed.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.643-649
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• 2008

The purpose of this study is to establish a standard for unit cooling load in central control type apartment applied district cooling. The model of unit household was selected. And the standard of coefficient of overall heat transmission, location of unit household, indoor air temperature, solar radiation & thermal conduction at window and interior load was selected, and region, expansion or non-expansion of balcony, pyeong type, azimuth, rate of window area was applied as parameter. And then cooling load simulation was performed. Based on the result of simulation, the synthetic district cooling load was presented for selecting heat source of apartment applied district cooling, and unit cooling load was analyzed according to design parameter.

• Journal of the Korean Ceramic Society
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• v.37 no.3
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• pp.219-226
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• 2000

Amorphous Ge20As20Se60 chalcogenide thin films were prepared by spin coating technique from mixed solutions of As40Se60 and Ge40Se60 dissolved in ethylenediamine. Films were prepared at a roating speed of 3500 rpm and spinning time was 10 second and heat-treateed at 27$0^{\circ}C$ for 1 hour. The resulting film thickness and RMS roughness were approximately 340 nm and 15$\AA$. Photostructure changes were investigated with 514.5nm Ar+ laser irradiation and heat-treatment. After Ar+ laser irradiation, transmittance and transmission efficiency decreased respectively up to 24.9% at 2.43 eV and 67.5% at 3.27 eV, and absorption edge shifted toward long wavelength. Optical bandgap changed from 2.03 to 1.83 eV, and absoprtion coefficient and absorption efficiency increased up to 0.33$\times$105cm-1 at 3.37eV and 88.3% at 1.31 eV, respectively. These photodarkening state were recovered reversibly by heat-treatment at 27$0^{\circ}C$ for 1 hour. Photodarkening and thermal bleaching effects by laser irradiation and heat-treatment revealed reversible amorphous-to-amorphous transition varying only coordination number.

• Journal of the Korean Society of Clothing and Textiles
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• v.41 no.1
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• pp.84-97
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• 2017

Water vapor and thermal transmission properties of high emotional garments are important to evaluate wear comfort; in addition, the measuring methods of these properties are also critical for breathable and warm suit fabrics. In this study, the water vapor and thermal properties of composite yarn fabrics made of CoolMax, Tencel, and Bamboo fibers with filaments were measured and compared according to the measuring method. Water Vapor Transmittance (WVT) of the fabric woven by the sheath/core composite yarn in the warp direction was the highest due to the small staple fiber volume in the sheath/core yarn structure and high air voids in the sheath/core yarn fabrics. This property was also the highest in fabrics woven by bamboo staple yarns in the weft direction, and was the lowest on hi-multi filament fabrics. However, water vapor resistance ($R_{ef}$) of these fabrics by KSK ISO 11092 showed the opposite results to the water vapor transmittance method ($CaCl_2$ method); in addition, its correlation coefficient was low. The correlation coefficient between $R_{ef}$ and the drying rate was 0.719; therefore, the measurement mechanism of $R_{ef}$ is analogous to the drying property measurement. The thermal conductivity of the fabrics woven with compact staple yarn showed a high value; however, the hi-multi filament fabric showed low thermal conductivity. Therefore, fiber characteristics affect thermal properties more than yarn structure. The correlation between thermal property and moisture transport was also low. This study showed that: water vapor transmittance was active at the loose yarn structure, dry heat transport was vigorous at the compact yarn structure, and heat transport was affected more by fiber characteristics than yarn structure. In conclusion, sheath/core composite yarns were relevant to the high absorptive cool suit along with siro-fil and CoolMax/Bamboo staple yarns that were relevant to the heat diffusive cool suit.

• Journal of the Korean Solar Energy Society
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• v.31 no.4
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• pp.66-71
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• 2011

This study focused on the application of the Passive Solar Chamber System (PSCS) as proposed by a previous study. The seasonal performance and sizing method for the system were investigated for a feasibility of the PSCS in Korean climate. For seasonal performance, heat and ventilation performances of the PSCS were analyzed for the months of January and August. This study proposed a simple configuration method in which the designer can decide on the system size at the preliminary design stage by using system efficiency, overall heat transfer coefficient transmission, monthly solar radiation, highest and lowest temperatures. During weeks that require heating, the system showed to acquire a daily average heat amount of $860.28Wh/m^2$ day. For cooling periods, the system was computed to supply a daily average natural ventilation of $1,360.2m^3/day$ to the room. Moreover, proposed sizing method and the overall computation results showed a 6.04~7.24% error of assessment.

• Journal of Bio-Environment Control
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• v.28 no.3
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• pp.255-264
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• 2019

In this study, we conducted the hot box tests to compare the changes in thermal insulation for the four types of multi-layer thermal screens by the used period after collecting them from the greenhouses in the field when they were replaced at the end of their usage. The main materials for these four types of multi-layer thermal screens were matt georgette, non-woven fabrics, polyethylene (PE) foam, chemical cotton, etc. These materials were differently combined for each multi-layer thermal screen. We built specimens ($70{\times}70cm$) for each of these multi-layer thermal screens and measured the temperature descending rate, heat transmission coefficient, and thermal resistance for each specimen through the hot box tests. With regard to the material combinations of multi-layer thermal screens, thermal insulation can be increased by applying a multi-layered PE foam. However, it is considered that the multi-layered PE foam significantly less contributes to heat-retaining than chemical wool that forms an air-insulating layer inside multi-layer thermal screens. For the suitable heat-retaining performance of multi-layer thermal screens, basically, materials with the function of forming an air-insulating layer such as chemical cotton should be contained in multi-layer thermal screens. The temperature descending rate, heat transmission coefficient, and thermal resistance of multi-layer thermal screens were appropriately measured through the hot box tests designed in this study. However, in this study, we took into consideration only the four kinds of multi-layer thermal screens due to difficulties in collecting used multi-layer thermal screens. This is the results obtained with relatively few examples and it is the limit of this study. In the future, more cases should be investigated and supplemented through related research.