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2015 Vol.24, Issue 3 Preview Page
Empirical Analysis on the Cooling Load and Evaporation Efficiency of Fogging System in Greenhouses

온실의 냉방부하 및 포그시스템의 증발효율 실험분석

Sang-Woon Nam1*
,
Dong-Uk Seo2
,
Hyun-Ho Shin1
남 상운1*
,
서 동욱2
,
신 현호1
1Department of Agricultural and Rural Engineering, Chungnam National University, Daejeon 305-764, Korea
2Institute of Agricultural Science, Chungnam National University, Daejeon 305-764, Korea
1충남대학교 지역환경토목학과
2충남대학교 농업과학연구소
*Corresponding author : swnam@cnu.ac.kr
30 July 2015. pp. 147-152
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Abstract

In order to develop the cooling load estimation method in the greenhouse, the cooling load calculation formula based on the heat balance method was constructed and verified by the actual cooling load measured in the fog cooling greenhouse. To examine the ventilation heat transfer in the cooling load calculation formula, we measured ventilation rates in the experimental greenhouse which a cooling system was not operated. The ventilation heat transfer by a heat balance method showed a relatively good agreement. Evaporation efficiencies of the two-fluid fogging system were a range of 0.3 to 0.94, average 0.67, and it showed that they increased as the ventilation rate increased. We measured thermal environments in a fog cooling greenhouse, and calculated cooling load by heat balance equation. Also we calculated evaporative cooling energy by measuring the sprayed amount in the fogging system. And by comparing those two results, we could verify that the calculated and the measured cooling load showed a relatively similar trend. When the cooling load was low, the measured value was slightly larger than calculated, when the cooling load was high, it has been found to be smaller than calculated. In designing the greenhouse cooling system, the capacity of cooling equipment is determined by the maximum cooling load. We have to consider the safety factor when installed capacity is estimated, so a cooling load calculation method presented in this study could be applied to the greenhouse environmental design.

Keywords
cooling efficiency
design factor
greenhouse cooling
spray rate
ventilation rate

온실의 냉방부하 산정방법 개발을 위하여 열수지 방법 에 기초한 냉방부하 산정식을 구성하고, 포그냉방 온실 에서 냉방부하를 실측하여 검증하였다. 포그냉방 온실의 냉각열량은 포그분사에 의한 증발수량에 물의 증발잠열 을 곱하여 구할 수 있다. 여기서, 증발수량은 포그 분사 량에 증발효율을 곱하면 구할 수 있으며, 즉 분무수량을 계측하고 포그시스템의 증발효율을 알면 온실의 냉방부 하를 실측할 수 있다. 따라서 온실의 냉방부하 실측을 위 하여 실험온실에서 포그시스템의 증발효율을 실험하고, 실험온실의 열환경 계측과 더불어 포그 분사량을 계측하 여 냉방부하 산정방법을 검토하였다. 먼저 냉방부하 산 정식의 환기전열량을 검토하기 위하여 냉방을 실시하지 않은 상태에서 환기량 실측 실험을 통해 비교한 결과 열수지식을 이용한 환기전열량 예측은 비교적 양호한 결 과를 보이는 것으로 나타났다. 이류체 포그시스템의 증 발효율은 0.3~0.94의 범위를 보였으며 평균 0.67로 나타 났고, 환기율이 증가함에 따라 커지는 것으로 나타났다. 포그냉방을 실시하면서 온실의 환경을 계측하여 열수지 식으로 냉방부하를 계산하고, 분무량 실측치로부터 증발 냉각열량을 구하여 비교한 결과 냉방부하 계산치와 실측 치는 대체로 유사한 경향을 보이는 것으로 나타났다. 냉 방부하가 낮은 경우에는 실측치에 비하여 약간 크게 예 측되었고, 냉방부하가 높은 경우에는 실측치보다 작게 예측되었다. 온실의 냉방시스템 설계 시에는 최대냉방부 하를 이용하여 냉방설비의 용량을 결정하게 된다. 따라 서 냉방부하가 큰 쪽에서 실측치보다 작게 예측되는 부 분은 검토가 필요하지만 설비용량 산정시의 안전계수를 고려하면 본 연구에서 제시한 냉방부하 산정방법은 온실 의 환경설계에 적용할 수 있는 것으로 판단된다.

키워드
냉방효율
설계인자
온실냉방
분무율
환 기율
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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 : 24
  • No :3
  • Pages :147-152
  • Received Date : 2015-06-26
  • Revised Date : 2015-07-09
  • Accepted Date : 2015-07-22
  • DOI :https://doi.org/10.12791/KSBEC.2015.24.3.147
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