Journal of agriculture & life science (농업생명과학연구)

Institute of Agriculture & Life Science, Gyeongsang National University (경상대학교 농업생명과학연구원)
권호 표지

Effects of the Open Level of the Side Window on the Control of the Temperature and Relative Humidity in the Fog Cooling Greenhouse

포그냉방 온실에서 측창개폐수준이 온습도 제어에 미치는 영향

  • Kim, Young-Bok (Dept. of bio-machinery engineering, Gyeongsang National Univ.(Insti. of Agri. & Life Sci.)) ;
  • Sung, Hyun-Soo (Dept. of bio-machinery engineering, Gyeongsang National Univ.(Insti. of Agri. & Life Sci.)) ;
  • Yun, Nam-Kyu (Protected horticulture research station, NIHHS, RDA) ;
  • Lee, Si-Young (R&D coordination division, Research policy bureau, RDA) ;
  • Hwang, Seung-Jae (Dept. of horticulture, Gyeongsang National Univ.(Insti. of Agri. & Life Sci.)) ;
  • Kim, Hyeon-Tae (Dept. of bio-machinery engineering, Gyeongsang National Univ.(Insti. of Agri. & Life Sci.)) ;
  • Lee, Jang-Pyung (Dept. of horticulture, Gyeongsang National Univ.(Insti. of Agri. & Life Sci.))
  • 김영복 (경상대학교 생물산업기계공학과(농업생명과학연구원)) ;
  • 성현수 (경상대학교 생물산업기계공학과(농업생명과학연구원)) ;
  • 윤남규 (농촌진흥청 국립원예특작과학원 시설원예시험장) ;
  • 이시영 (농촌진흥청 연구정책국 연구운영과) ;
  • 황승재 (경상대학교 원예학과(농업생명과학연구원)) ;
  • 김현태 (경상대학교 생물산업기계공학과(농업생명과학연구원)) ;
  • 이장평 (경상대학교 원예학과(농업생명과학연구원))
  • Received : 2011.10.10
  • Accepted : 2011.12.20
  • Published : 2011.12.30
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Abstract

Effects of the open level of the side window were studied to control the temperature and relative humidity in the fog cooling greenhouse. The greenhouse was cooled by air atomizing spray nozzles of the air and water two-fluid process. The control process includes the measuring of environmental variables, setting and coding of the water balance equations and heat balance in greenhouse, calculating of the roof window open and spray water, and operating of the motor and pump. The target temperature and relative humidity were set at $28^{\circ}C$, 75%, respectively. The three modes of the side window open level were 0%, 50% and 100%. The average dry bulb temperatures of the inside air were 28.2, 27.2 and $26.3^{\circ}C$, respectively and their standard deviation was ranged from $0.4^{\circ}C$to $0.8^{\circ}C$. Also the relative humidity of the 0% mode was the best controlled one with the average of 76.3% and the standard deviation of 2.1%.

하절기 온실 내 온도와 상대습도를 동시에 제어할 목적으로 압축공기를 이용한 이류체 분무 포그 냉방을 도입한 유리온실에서 측창의 개폐수준이 온실내의 온도와 상대습도 제어에 어떠한 영향을 주는지 분석하였다. 제어과정은 온실 환경변수들을 측정하고, 이를 반영하여 온실 내 수분평형방정식과 열평형방정식을 정립한 다음, 이 방정식들을 프로그램으로 코딩하여 각 사이클의 천창 개폐량과 포그 분무량을 결정하고 제어하였다. 온실의 온습도 제어목표는 온도와 습도를 각각 28, 75%로 설정하였고, 실험은 측창이 전혀 열리지 않은 0%, 50% 열린 경우, 100% 열린 경우 세 가지 모드를 비교분석하였다. 제어실험결과 온실 내 건구온도의 평균은 모드에 따라 각각 28.2, 27.2 $26.3^{\circ}C$로 나타났으며, 표준편차는 $0.4{\sim}0.8^{\circ}C$이었다. 상대습도는 측창을 완전히 닫은 모드인 0%의 경우 평균 76.3% 정도로서 목표 상대습도인 75%에 상당히 근접해서 제어되고 있었으며, 표준편차가 2.1%로서 다른 모드에 비해 상당히 안정된 범위에서 유지되는 것으로 나타났다. 0%의 모드에서 가장 목표온도로 잘 제어되고 있는 것으로 나타났다.

Keywords

Acknowledgement

Supported by : 농촌진흥청

References

  1. Abdel-Ghany, A. M. and T. Kozai. 2006. Cooling efficiency of fogging systems for greenhouses, Biosystems Eng. 94: 97-109. https://doi.org/10.1016/j.biosystemseng.2006.02.008
  2. ASHRAE standard 41.6. RA. 2006.
  3. Businger, J. A. 1963. The glasshouse (greenhouse) climate, in physics of plant environment. pp.277-318. Amsterdam, North-Holland.
  4. CR1000 measurement and control system operator's manual. 2010. Campbell Sci. Inc.
  5. Guerrero, F. V., K. Murat, F. R. Efren, L. Raphael, A. Avraham, K. Chieri, and A. G. Gene. 2010. Developing a control strategy for greenhouses equipped with natural ventilation and variable pressure fogging: Evapotranspiration models and simulated comparison of fixed and variable pressure fog cooling, 2010 ASABE annual international meeting, Paper Number:1009388.
  6. Handarto, M. H., E. Goto, and T. Kozai. 2007. Experimental verification of control logic for operation of a fog cooling system for a naturally ventilated greenhouse. Env. Contr. Biol. 45: 47-58. https://doi.org/10.2525/ecb.45.47
  7. Herry, S. and R. Yayu. 2008. Determination of convective coefficient at the outside cover of a monitor greenhouse in Indonesia. J. Appl. Sci. Env. Sanitation. 3: 37-46.
  8. Jolliet, O.. 1994. A model for predicting and optimizing humidity and transpiration in greenhouses. J. Agr. Eng. Res. HORTITRANS. 57: 23-37. https://doi.org/10.1006/jaer.1994.1003
  9. Kim, J. H., C. S. Kim, K. H. Koo, and K. M. Lee. 1995. A fundamental study for the automatic control system in greenhouse using microcomputer(III) -A variation of temperature and humidity by the window opening ways of the even-span type house-. KSAM. J. Biosystems Eng. 20: 162-172.
  10. Kim, M. K., K. S. Kim, and H. J. Kwon. 2001. The cooling effect of fog cooling system as affected by air exchange rate in natural ventilation greenhouse. KSBEC. J. Env. Contr. 10: 10-14.
  11. Kittas, C., N. Katsoulas, T. Bartzanas, T. Boulard, and M. Mermier. 2005. Effect of vents' opening and insect screen on greenhouse ventilation. International conference "Passive and low energy cooling 59 for the built environment". Santorini, Greece.
  12. Kittas, C., T. Boulard, and G. Papadakis. 1997. Natural ventilation of a greenhouse with ridge and side openings: sensitivity to temperature and wind effects, Tran. of the ASAE. 40: 415-425.
  13. Li, S., and D. H. Willitsa. 2008. Comparing low-pressure and high-pressure fogging systems in naturally ventilated greenhouses, Biosystems Eng. 101: 69-77. https://doi.org/10.1016/j.biosystemseng.2008.06.004
  14. Min, Y. B., Y. C. Yoon, M. R. Huh, D. H. Kang, and H. T. Kim. 2010. Cooling control of greenhouse using roof window ventilation by simple fuzzy algorithm. IALS, GNU. J. Agr. Life Sci. 44. Korea.
  15. Molina-Aiza, F. D., D. L. Valeraa, A. A. Penaa, J. A. Gilb and A. Lopeza. 2009. A study of natural ventilation in an Almería-type greenhouse with insect screens by means of tri-sonic anemometry. Biosystems Eng. 104: 224-242. https://doi.org/10.1016/j.biosystemseng.2009.06.013
  16. Nam S. W. 2000. Application of heat balance model to design of ventilating and cooling greenhouses. KSBEC. J. of Env. Contr.. ISSN 1229-4675. 9: 201-206.
  17. Shu-zhen Liu, Yong He, Yu-bao Zhang, and Xiang-wen Miao. 2005. Prediction and analysis model of temperature and its application to a natural ventilation multi-span plastic greenhouse equipped with insect-proof screen. J Zhejiang Univ Sci. B. 6: 523-529.
  18. Study group for plug seedling production. 2011. cafe.daum.net/plugseedling.
  19. Teitel, M., O. Liran, J. Tanny, and M. Barak. 2008. Wind driven ventilation of a mono-span greenhouse with a rose crop and continuous screened side vents and its effect on flow patterns and microclimate. Biosystems Eng. 101: 111-122. https://doi.org/10.1016/j.biosystemseng.2008.05.012
  20. Waleed Ibrahim Ramadan Agmail. 2009. Robust H-infinity control of greenhouse ventilation and fogging. 2009 ASABE annual international meeting. Paper number: 096100.
  21. Yasuba, K., H. Kurosaki, M. Takaichi, H. Omori, H. Kawashima, and T. Hoshi. 2010. A system to control greenhouse air temperature and humidity by adjusting Enthalpy and by mist cooling. J. SHITA. 22: 29-35. https://doi.org/10.2525/shita.22.29