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2019 Vol.28, Issue 4 Preview Page
Determination of Thermal Radiation Emissivity and Absorptivity of Thermal Screens for Greenhouse

온실 스크린의 장파복사 방사율 및 흡수율 결정

Adeel Rafiq1
,
Wook Ho Na2
,
Adnan Rasheed1
,
Hyeon Tae Kim3
,
Hyun Woo Lee124*
라 피크아딜1
,
나 욱호2
,
라 쉬드아드난1
,
김 현태3
,
이 현우124*
1Department of Agricultural Engineering, Kyungpook National University, Daegu 41566, Korea
2Institute of Agricultural Science and Technology, Kyungpook National University, Daegu 41566, Korea
3Dept. of Bio-Industrial Machinery Eng., Gyeongsang National Univ. (Insti. of Agric. & Life Sci.), Jinju 660-701, Korea
4Smart Agriculture Innovation Center, Kyungpook National University, Daegu 41566, Korea
1경북대학교 농업토목공학과
2경북대학교 농업과학기술연구소
3경상대학교 생물산업기계공학과
4경북대학교 스마트농업혁신센터
*Corresponding author: whlee@knu.ac.kr
30 November 2019. pp. 311-321
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Abstract

Greenhouse farmers often use thermal screens to reduce greenhouse heating expenses during the winter, and for shade during hot, sunny days in the summer, as it is an inexpensive solution to temperature control relative to other available options. However, accurate measurements of their emitted and absorbed radiations are important for the selection of suitable screens that offer maximum performance. Material’s ability to save energy is highly dependent on these properties. Limited studies have investigated the measurement of these properties under natural conditions, but they are only applicable to materials having partial porosities. In this work, we describe a new radiation balance method for determining emissive power and absorptive capacity, as well as reflectivity, transmissivity and emissivity of materials having complete and partial transparency by using pyrgeometer and net radiometer. In this study, four materials with zero porosity, were tested. The emissivity value of PE, LD-13, LD-15 and PH-20 was 0.439±0.020, 0.460±0.010, 0.454±0.004, and 0.499±0.006, respectively. All tested samples showed high emitted radiation as compared to absorbed radiation.

Keywords
image j
net radiometer
pyrgeometer
reflectance

온실에서 겨울철 야간에는 열손실을 줄이기 위한 목적으로, 여름철 주간에는 차광을 위한 목적으로 스 크린을 사용하고 있다. 온실의 냉난방 에너지 절감효과에 큰 영향을 미치는 스크린의 장파복사 방사율과 흡수 율은 온실에 설치할 적절한 스크린을 선택하는데 있어서 중요한 요소가 되며 이러한 특성값들을 정확하게 측 정할 수 있는 방법이 필요하다. 외부 환경조건에서 스크린의 장파복사 특성의 측정과 관련된 연구가 일부 수 행된 바 있지만 모든 종류의 스크린에 적용할 수 있는 방법은 아니고 공극이 있는 스크린 자재에만 적용이 가 능한 방법이다. 본 연구에서는 순복사계 및 야간복사계를 사용하여 온실 스크린의 장파복사 흡수량과 방사량을 측정하고, 방사율, 흡수율 및 투과율을 결정하는 새로운 방법을 제시하였다. 특성값의 측정은 공극이 0인 4가 지 종류의 스크린 자재에 대하여 수행하였다. 모든 자재가 장파복사 방사량이 흡수량보다 높게 나타났다. PE, LD-13, LD-15 and PH-2의 장파복사 방사율은 각각 0.439±0.020, 0.460±0.010, 0.454±0.004, and 0.499±0.006 범위로 나타났다.

키워드
반사율
순복사계
야간복사계
이미지J
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Information
  • Publisher :The Korean Society for Bio-Environment Control
  • Publisher(Ko) :(사)한국생물환경조절학회
  • Journal Title :Protected Horticulture and Plant Factory
  • Journal Title(Ko) :시설원예ㆍ식물공장
  • Volume : 28
  • No :4
  • Pages :311-321
  • Received Date : 2019-06-30
  • Revised Date : 2019-08-20
  • Accepted Date : 2019-08-22
  • DOI :https://doi.org/10.12791/KSBEC.2019.28.4.311
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