• Journal of Bio-Environment Control
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• v.5 no.1
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• pp.34-42
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• 1996

This study was conducted to investigate the physical and optical properties of polypropylene and polyester thermal curtains, in which tensile strength, heat reservance and light transmission of two different materials were measured. The results from this study are as follows. 1. The tensile weight of different materials were ranged from 3.4kg to 13.4kg, according to the thickness of materials, but that no difference in the tensile strength was appeared between the two materials. The Elongation of polypropylene materials and the tensile weight and strength of polyester materials were greater than any other materials. 2. The light transmittances of two materials were ranged from 50.3% to 81.7 %, light transmittances in polypropylene were higher by 20-30%,than those in polyester. 3. The heat reservances of two materials were ranged from 18.2% to 41.2%, in which polypropylene showed better performance than polyester. 4. From the results of the test, the polypropylene thermal material was better in elongation, heat reservances and light transmittances, but polyester thermal material was better in tensile strength and light isolation than the other material.

• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.341-347
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• 2009

Experiments and computations were conducted to investigate the heat insulation characteristics of multi layer materials for cultivation greenhouse. In case of the experiments, measurements of temperature were carried out with a K-type thermocouples and data logger to research the heat transfer in the experimental module generated by the heat source. A thermal conductivity meter, QTM-500 based on modified transient hot wire method was used to measure the thermal conductivity of multi layer materials. The numerical analyses were performed by commercial code CFX-11 according to the variation of multi layer materials without air layer. The experimental results showed that the heat insulation of multi layer materials was higher than single layer materials by 50~90%. It was found that the effect of heat insulation was raised by the combination of multi layer materials.

• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.332-340
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• 2009

In this study, the thermal insulation effectiveness of the greenhouse insulators by the installation methods was investigated to find the right installation way of the insulation materials. Physical properties of the insulators such as thickness, air transmissivity, apparent density, ultraviolet rays cutoff ratio, reflectance, thermal conductivity, moisture absorptivity were evaluated and the insulation ability of the insulators were measured by the module experiments. For the same insulator, the insulation ability of the case with the outward direction of the black colored face, i.e., with the inward direction of the white colored face, was better than that of vice versa. The case of the black colored both surfaces was better than the case of the white colored both surfaces. For aluminium reflection material, the case with the outward direction of the lustre face, i.e., with the inward direction of the non-lustre face, was better than that of vice versa. For the same material with the inner thin polyethylene foam (or polyester) and the chemical wool, the case with the outward direction of the inner thin polyethylene foam (or polyester), i.e., with the inward chemical wool, was better than that of vice versa. Addition of the inner thin polyethylene foam increased the insulation effect very much.

• 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.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.419-428
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• 2021

In order to develope a mobile-based greenhouse energy calculation program, firstly, the overall thermal transmittance of 10 types of major covers and 16 types of insulation materials were measured. In addition, to estimate the overall thermal transmittance when the cover and insulation materials were installed in double or triple layers, 24 combinations of double installations and 59 combinations of triple installations were measured using the hotbox. Also, the overall thermal transmittance value for a single material and the thermal resistance value were used to calculate the overall thermal transmittance value at the time of multi-layer installation of covering and insulating materials, and the linear regression equation was derived to correct the error with the measured values. As a result of developing the model for estimating thermal transmittance when installing multiple layers of coverings and insulating materials based on the value of overall thermal transmittance of a single-material, the model evaluation index was 0.90 (good when it is 0.5 or more), indicating that the estimated value was very close to the actual value. In addition, as a result of the on-site test, it was evaluated that the estimated heat saving rate was smaller than the actual value with a relative error of 2%. Based on these results, a mobile-based greenhouse energy calculation program was developed that was implemented as an HTML5 standard web-based mobile web application and was designed to work with various mobile device and PC browsers with N-Screen support. It had functions to provides the overall thermal transmittance(heating load coefficient) for each combination of greenhouse coverings and thermal insulation materials and to evaluate the energy consumption during a specific period of the target greenhouse. It was estimated that an energy-saving greenhouse design would be possible with the optimal selection of coverings and insulation materials according to the region and shape of the greenhouse.

• Journal of Convergence for Information Technology
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• v.8 no.1
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• pp.227-233
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• 2018

The purpose of this study was to develop a warm cover for greenhouse with excellent thermal insulation and to propose ways of commercialization of the product. Feathers were used as filling materials because they formed the air layer to enhance insulation. Instead of downs for clothing or other textile products, we used disposed feathers. The developed product covers the outside of the greenhouse to keep the crops warm. It has multiple layers including feathers as filling materials, padding, inside fabric, heat insulation materials and outer fabric. It has proven to improve the insulation ratio. We developed other kinds of warm covers that are applicable to the inside of the greenhouse or the small houses in the greenhouse. Also, R&D system of educational industrial complex enables us to commercialize the products and building marketing strategies for them. This technology contributes to the expansion of energy-saving facilities for farmers, and it can serve the development and spread of various products utilizing feather.

• Korean Journal of Plant Resources
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• v.13 no.3
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• pp.208-212
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• 2000

The effect of heat covering materials during cultivation of Shigyoku grape was examined on the effect of protection from freezing damage, labor reduction, and disease resistance during the wintering. This experimentwas accomplished using different combination of heat covering materials from the end of Nov as follows: straw and heat conservation cover B, kilding, color fabric A, and white needle punching fabric. Capacity of heat conservation was the least form white needle punching fabric, and the differences of other materials was slight. Early sprouting occurred by the treatment with heat conservation cover B, and the rate of sprouting was about 70.7% after 9 days of sprouting, showing 2.3-12.5% increase. Growth effect was not differ between heat conservation materials. Disease and insects occurred by the in dice 3.0-3.2 of crown gall from the heat conservation cover B treatment. Other damages were not observed or very little from other treatments. Demand of labor during steps of these treatments was more observed by 6% for kilding than heat conservation cover B, and those of color fabric A and white needle punching fabric were reduced by 6 and 15%, respectively.

• Journal of Bio-Environment Control
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• v.13 no.4
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• pp.251-257
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• 2004

This experiment was carried out to investigate the effects of different covering materials and methods on heat insulation of a plastic greenhouse, growth and yield of tomato. Night air and soil temperatures in a double-layer greenhouse with external multifold thermal cover (MTC; eight-ounce cassimere+four-fold polyform+double-fold non-woven fabric+single-fold polypropylene covering were about $1^{\circ}C$ lower than in that with internal MTC covering, but about $3^{\circ}C$ higher than in that with an EVA film screen. Tomato yield in the external MTC covering increased by $2\%\;and\;19\%$ as compared to that in the internal MTC covering and the non-covering of MTC, respectively, due to its high light transmission and insulation effect. Night air temperatures in a double-layer greenhouse with external MTC covering and with thermal screen (polyester plus aluminium) were $2.2^{\circ}C\;and\;4.5^{\circ}C$ higher than those in a double-layer greenhouse with an external MTC covering and in a double-layer greenhouse equipped an EVA film screen, respectively. Tomato yield in the treatment with external MTC covering and a thermal screen was $18\%\;and\;37\%$ greater than that in the external MTC covering and in an EVA film screen, respectively. Results indicate that tomato could be grown without heating or with minimal heating in a double-layer greenhouse covered with MTC and a thermal screen during the winter season in sourthern regions of Korea.

• 종축개량
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• v.21 no.1
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• pp.82-86
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• 1999

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.590-596
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• 2020

The fabric used for military winter inner clothing(top) is quilted with padded cotton to provide warmth. This quilting fabric is generally manufactured with yarns that intersect and are sewn substantially between the fabric and cotton. Thus, it is impossible to separate the fabric and cotton once after the quilting fabric is manufactured, which can result in a significant loss of fabric and cotton when separated. In this study, after fabricating the quilting fabric, we investigated a method to stabilize change rate of thickness and increase the warmth keeping property through subsequent processing without damaging the fabric. A relatively method of passing the quilting fabric through a part of the cotton production facility was used generally, and the following results were obtained. This indicates that after the quilting fabric was manufactured, the warmth keeping property was improved through the subsequent processing steps, so that the change rate of thickness due to washing was stabilized.