Analysis on Heat Loss of Single-span Greenhouse Using Small-scaled Wind Tunnel

Young Hwa Kim; Hyung kow Kim; Tae suk Lee; Sung sik Oh; Young sun Ryou

doi:10.12791/KSBEC.2020.29.1.73

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2020 Vol.29, Issue 1 Preview Page Next Page

Original Articles

Analysis on Heat Loss of Single-span Greenhouse Using Small-scaled Wind Tunnel 소형풍동을 이용한 단동 비닐온실의 열손실 분석

31 January 2020. pp. 73-79

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Abstract

The objective of this study is to analyze the heat transfer loss of covering materials in a single-span plastic greenhouse under the steady-state wind environment. To achieve this objective, the following were conducted: (1) design of a small-scaled wind tunnel (SCWT) to analyze heat losses of the greenhouse and its performance; (2) determination of the overall heat transfer coefficient (OHTC) for the covering materials using a small-scaled greenhouse model. The SCWT consists of the blowing, dispersion, steady flow, reduction and testing areas. Each part of the SCWT was customized and designed to maintain air flow at steady state and to minimize the variances in the SCWT test. In this study, the OHTCs of the covering materials were calculated by separating each with the roof, side wall, front and back of the small-scaled greenhouse model. The results of this study show that the OHTC of the roof increases as wind speed increases but the zones in which the increase rate of the OHTC decreased, were distinguished by wind tunnel wing speed of 2 ms^-1. For the side wall, the increase rate of the OHTC was particularly higher in the 0-1 ms^-1 zone.

Keywords

covering materials

overall heat transfer coefficient

surface temperature

wind direction

본 연구는 일정한 풍환경하에 온실 피복재 관류전열손실을 분석하기 위하여 온실 열손실 분석용 소형 풍동을 제작하고 그 성능을 분석하였으며 모형온실을 적용하였을 때의 관류전열손실을 분석하였다. 소형 풍동은 시험부 측 공기흐름이 정상상태를 유지하고 편차를 최소화하기 위하여 풍동의 각 요소를 반영하여 구성하였으며 송풍부, 확산부, 정류부, 축소부, 시험부로 구성하였다. 소형 풍동의 형태는 개방형, 토출식으로 결정하였고, 시험부 규격은 제작하고자 하는 모형온실의 규격과 상사비율, 시험부의 단면 폐쇄율을 감안하여 결정하였다. 상사비율을 풍동실험에 적용할 모형은 농업시설 중 가장 큰 비중을 차지하고 있는 단동 비닐온실을 대상으로 하였다. 소형풍동 내 풍속을 조절함에 따라 나타나는 모형온실 피복재의 관류전열계수는 피복재 면을 크게 지붕면과 측벽면, 앞뒷면으로 나누고 각 면별 계측 데이터를 평균 내어 산출하였다. 지붕면은 풍속이 증가함에 따라 전열계수도 증가하나 증가폭이 감소하는 구간은 배치각도에 따라 1-2ms^-1과 2-3ms^-1으로 구분되어지는 것으로 판단되었다. 측벽면의 전열계수가 증가하는 폭이 큰 구간은 0-1ms^-1 구간인 것으로 판단된다.

키워드

열전달계수

표면온도

풍향

피복재

References

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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 : 29
No :1
Pages :73-79
Received Date : 2019-07-22
Revised Date : 2020-01-08
Accepted Date : 2020-01-20
DOI :https://doi.org/10.12791/KSBEC.2020.29.1.73

Journal of Bio-Environment Control ISSN:1229-4675(Print) 2765-3641(Online) 생물환경조절학회지

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