Estimation of Thermal Performance and Heat Loss in Plastic Greenhouses with and without Thermal Curtains

Hyung-Kweon Kim, Geum-Choon Kang, Jong-Pil Moon, Tae-Seok Lee and Sung-Sik Oh
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Hyung-Kweon Kim: Department of Agricultural Engineering, National Institute of Agricultural Sciences, RDA, Jeonju 54875, Korea
Geum-Choon Kang: Department of Agricultural Engineering, National Institute of Agricultural Sciences, RDA, Jeonju 54875, Korea
Jong-Pil Moon: Department of Agricultural Engineering, National Institute of Agricultural Sciences, RDA, Jeonju 54875, Korea
Tae-Seok Lee: Department of Agricultural Engineering, National Institute of Agricultural Sciences, RDA, Jeonju 54875, Korea
Sung-Sik Oh: Department of Agricultural Engineering, National Institute of Agricultural Sciences, RDA, Jeonju 54875, Korea

Energies, 2018, vol. 11, issue 3, 1-11

Abstract: Greenhouses are important for stable food production, but require large amounts of energy to maintain their microclimate in regions with harsh climates. This study assessed the internal thermal insulation performance of thermal curtains in double-layered plastic greenhouses in Korea in winter using cover surface temperature changes and heat transfer coefficients (U values). The thermal curtain performance increased as the temperatures of the inner cover surface increased and the outer cover surface decreased. The outer cover surface temperature with thermal curtains was almost uniformly 1.9 °C lower than that without thermal curtains, whereas the inner cover surface temperature was higher, demonstrating the warming effect of thermal curtain use. Under a constant indoor and outdoor air temperature difference, the daily average heating energy consumption was directly proportional to the U value. The U values were 2.76 W m ?2 °C ?1 with thermal curtains and 3.85 W m ?2 °C ?1 without thermal curtains. In double-layered plastic greenhouses that were covered with 0.1-mm-thick polyethylene, incorporating thermal curtains at night resulted in energy savings of about 28.7%, which was related to the decrease in U values. Installing and using thermal curtains at night in winter is a highly economical method for heating savings. These results can be used to promote energy savings in greenhouses in harsh climates.

Keywords: thermal insulation; cover surface temperature; energy consumption; U value (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2018
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (7)

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