• Title, Summary, Keyword: 보온성

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Effects of Covering Methods for Insulation on Heating Cost, Growth and Yield of Tomato in Greenhouse (보온피복방법이 난방비와 토마토 생육 및 수량에 미치는 영향)

  • 권준국;최영하;박동금;이재한
    • Proceedings of the Korean Society for Bio-Environment Control Conference
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    • pp.58-61
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    • 1999
  • 농가에서 주로 사용하고 있는 플라스틱하우스의 보온방법은 부직포로 된 보온 커텐을 2중 혹은 3중으로 설치하는 것이 대부분이다. 근래에는 영남 남부지역의 고추재배 농가를 중심으로 단동형 하우스에 다겹보온시트나 보온덮개를 외면피복하여 보온성을 높이려는 방법이 증가추세에 있다. 본 실험에서는 다겹보온시트의 설치방법에 따른 보온특성과 토마토의 생육 및 수량에 미치는 영향을 구명하고자 수행하였다. (중략)

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Analysis of Heating Characteristics of Multi-Layered Insulation Curtain with Silica Aerogel in Greenhouses (실리카 에어로겔을 이용한 다겹보온커튼의 온실 난방 특성 분석)

  • Jin, Byung-Ok;Kim, Hyung-Kweon;Ryou, Young-Sun;Lee, Tae-Seok;Kim, Young-Hwa;Oh, Sung-Sik;Kang, Geum-Choon
    • Protected Horticulture and Plant Factory
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    • v.29 no.4
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    • pp.320-325
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    • 2020
  • This study aimed to analyze thermo-keeping and economic feasibility by utilizing silica aerogel, which has been attracting attention as a new material, complementing the disadvantages of the conventional multi-layered thermal screen, and producing and installing multi-layered thermal screen. The multi-layered thermal screen used in the experiment was produced in two combinations using a non-woven fabric containing silica aerogel and measured and compared the temperature and fuel consumption changes due to differences in practice with the multi-layered thermal screen being sold and used on the market. Experimental results show that the temperature and relative humidity changes due to the differences of the multi-layered thermal screens in the single-span greenhouse and the multi-span greenhouse were small but remained almost the same temperature and relative humidity. It is judged that this shows that the multi-layered thermal screen using silica aerogel is not inferior to the conventional multi-layered thermal screen. As a result of a comparative analysis of heating energy, the aerogel-based multi-layered thermal screen reduced fuel consumption by about 15% in the single-span greenhouse and about 20% in the multi-span greenhouse compared to the conventional multi-layered thermal screen. It is clear that heating energy is saved as a greenhouse size and duration increase. It was found that the silica aerogel-based multi-layered screen was more breathable and warmer than the conventional multi-layered thermal screen, but It was found that the multi-layered screen used in the multi-span greenhouse was heavier and stiff compared with the conventional multi-layered thermal screen, indicating less workability and operability. Therefore, improvements were applied to the multi-layered screens used in the single-span greenhouses. It was confirmed that the replacement of internal insulation materials reduced thickness and improved stiffness so that there could be sufficient possibility for farmers to use.

Heat Insulation Characteristics of Multi Layer Materials for Greenhouse (시설원예용 조합형 다겹보온자재의 보온 특성)

  • Chung, Sung-Won;Kim, Dong-Keon;Lee, Suk-Gun;Nam, Sang-Heon;Lee, Yong-Beom
    • Protected Horticulture and Plant Factory
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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.

Comparison of Thermal Insulation of Multi-Layer Thermal Screens for Greenhouse: Results of Hot-Box Test (온실용 다겹보온자재의 보온성 비교 -Hot box 시험 결과를 중심으로-)

  • Yun, Sung-Wook;Lee, Si-Young;Kang, Dong-Hyeon;Son, Jinkwan;Park, Min-Jung;Kim, Hee-Tae;Choi, Duk-Kyu
    • Protected Horticulture and Plant Factory
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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.

Evaluation of Thermal Insulation Properties of Covering Materials to Protect Peach Trunks against Freezing Injury (복숭아 주간부 동해 예방을 위한 피복재의 보온성 평가)

  • Shin, Hyunsuk;Yun, Seok Kyu;Choi, In Myung;Kim, Sung Jong;Yun, Ik Koo;Nam, Eun Young;Kwon, Jung Hyun
    • Protected Horticulture and Plant Factory
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    • v.25 no.4
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    • pp.288-293
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    • 2016
  • The study was performed to evaluate thermal insulation covering materials (TICMs) to protect peach trunks against freezing temperatures in winter season by investigating thermo-physical properties and practical thermal insulation effect of the TICMs which was made of white non-woven fabrics, yellow paper sheets, and waterproof fabric pads. Among the three TICMs, Waterproof fabric pad (double layer) possessed the best performance about thermal insulation rate and thermal resistance among three kinds of TICMs. Day thermal insulation effects of waterproof fabric pad, which prevent from temperature rise on the bark tissues of trunks during the day time, were $14.09^{\circ}C$. Night thermal insulation effects of them, which prevent from temperature decline on the bark tissues of trunks at night time, were $7.23^{\circ}C$. Waterproof fabric pad showed the highest day and night thermal insulation effects. Thus our results suggest that development of TICMs using waterproof fabric pad might be helpful to protect the bark tissues of trunks from freezing injury.

A Study of the Performance Improvement for Quilting Fabric via Postprocessing (퀼팅원단 후속가공을 통한 기능성 향상 연구)

  • Kim, Ji-Hoon;Ko, Hye-Ji
    • 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.

Effects of Covering Materials and Methods on Heat Insulation of a Plastic Greenhouse and Growth and Yield of Tomato (플라스틱하우스의 보온피복 재료 및 방법이 보온력과 토마토의 생육 및 수량에 미치는 영향)

  • Kwon Joon Kook;Lee Jae Han;Kang Nam Jun;Kang Kyung Hee;Choi Young Hah
    • Protected Horticulture and Plant Factory
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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.

Occurrence and Repression of Off-Odor in Cooked Rice during Storage under Low Temperature Warming Condition of Electric Rice Cooker (전기밥솥으로 저온보온한 쌀밥의 이취 발생 및 억제)

  • Park, Seok-Kyu;Ko, Yong-Duck;Cho, Young-Sook;Shon, Mi-Yae;Seo, Kwon-Il
    • Korean Journal of Food Science and Technology
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    • v.29 no.5
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    • pp.919-924
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    • 1997
  • The changes in physicochemical properties of cooked rice stored in an electric rice cooker at different temperature (63, 66, 69 and $72^{\circ}C$) were investigated. The growth of thermophilic bacteria was gradually increased in all samples with storage time up to 6 hours and increased rapidly afterward. The bacterial growth rate was higher during storage at low temperature than at high temperature, and the bacterial number generally reached the maximum at 18 hours of the storage. The number of bacteria in sample stored at $63^{\circ}C$ was increased to $10^6$ CFU/g after storage for 6 hours. The heat treatment at 6 hours of storage decreased the bacterial number to $10^5 $ CFU/g at 8 hours of storage. Bacterial number was gradually increased with storage time after the first heat treatment. When the sample was reheated after 8 hours of storage, the bacterial number was reduced to the level at which off-odor was not detected after storage for 24 hours. During the storage, moisture content of heat-treated sample was lower than that of sample stored at $63^{\circ}C$ but higher than that of sample stored at $72^{\circ}C$. The L value of heat-treated sample was higher than that of the sample stored at $72^{\circ}C$, but lower than that of the sample stored at $63^{\circ}C$. The b value showed an opposite trend to the L value with regard to the storage temperature. Changes in texture were not remarkable during the storage for the sample heat-treated and stored at low temperature. The occurrence of off-odor and browning was depressed in the heat-treated sample, and the texture and overall eating quality were more acceptable than the samples stored at low temperature.

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Sensory Characteristics of Cooked Rice Stored in an Electric Rice Cooker (전기보온밥솥으로 보온한 쌀밥의 관능적 특성)

  • Lee, Young-Joo;Min, Bong-Kee;Shin, Myung-Gon;Sung, Nae-Kyung;Kim, Kwang-Ok
    • Korean Journal of Food Science and Technology
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    • v.25 no.5
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    • pp.487-493
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    • 1993
  • The changes of cooked rice stored in an electric rice cooker at different temperature were investigated using sensory and mechanical methodology. The desirability of cooked rice was deteriorated during storage, particulary cooked rice stored at $80^{\circ}C$ had the lowest desirability. As the storage time increased, glossiness, clumpiness, adhesiveness, moistness and sweet flavor of cooked rice decreased but browning and off-flavor increased. The higher storage temperature resulted in the lower in glossiness, firmness, cohesiveness, moistness, sweet flavor and in the more browning, adhesiveness and off-flavor. L and b values measured by Hunter Color Difference Meter were highly correlated with the sensory glossiness and color.

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