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설계 변수 선택이 온실의 냉난방부하 산정에 미치는 영향

Effect of Design Value Selection on Heating and Cooling Load Calculation in Greenhouses

  • 남상운 (충남대학교 지역환경토목학과) ;
  • 신현호 (충남대학교 지역환경토목학과)
  • Nam, Sang-Woon (Department of Agricultural and Rural Engineering, Chungnam National University) ;
  • Shin, Hyun-Ho (Department of Agricultural and Rural Engineering, Chungnam National University)
  • 투고 : 2018.08.17
  • 심사 : 2018.09.14
  • 발행 : 2018.10.30

초록

온실의 냉난방부하 산정을 위해 설계자가 선택해야할 주요 변수들에 대하여, 이들 설계 변수가 냉난방부하에 미치는 영향을 평가하기 위해서 각각의 설계 변수값을 변화시키면서 시뮬레이션을 실시하였으며, 이를 바탕으로 특별히 선택에 주의를 기울여야 할 설계 변수를 제안하였다. 난방부하에 가장 큰 영향을 미치는 설계 변수는 피복재의 열관류율이고, 다음으로 설계외기온인 것으로 나타났다. 연동수에 따른 설계 변수의 영향은 차이가 거의 없는 것으로 나타났다. 단동 온실의 경우에는 지중전열 관련 설계 변수의 영향을 무시할 수 없을 것으로 생각되지만, 연동 온실의 경우에는 지중전열 관련 변수 및 틈새환기율의 영향이 미미한 것으로 판단되었다. 냉방부하에 가장 큰 영향을 미치는 설계 변수는 온실내로 유입되는 일사량과 증발산계수이고, 다음으로 실내외 기온차, 환기율인 것으로 나타났다. 설계 변수의 영향은 단동 온실과 연동 온실에서 큰 차이를 보였으나, 연동수에 따른 차이는 거의 없는 것으로 나타났다. 피복재의 열관류율은 단동 온실이나 연동 온실 모두 영향이 미미한 것으로 나타났지만, 실내외 기온차 및 환기율의 경우에는 냉방부하에 미치는 영향을 무시할 수 없을 것으로 생각되며, 특히 연동 온실에서 그 영향이 더 큰 것으로 판단되었다. 냉방부하를 산정할 때 실내 목표온도를 낮게 설정할수록 설계 변수의 선택에 신중해야 한다. 특히, 실내 목표온도를 외기온 보다 낮게 설정하면 환기율 및 열관류율 값이 냉방부하를 증가시키는 방향으로 바뀌므로 더욱 주의해야 한다. 환기율이 낮을 때는 설계 변수 중 설계일사량과 증발산계수의 선택에 주의해야 하고, 환기율이 높을 때는 실내 설정온도와 설계외기온의 선택에 신중을 기해야 한다.

For the main variables to be selected by the designer for the heating and cooling load calculation in greenhouses, in order to evaluate the effect of these design values on the heating and cooling load, the simulations were carried out by varying the respective design values. Based on these results, we proposed the design values which should pay special attention to selection. The design values which have the greatest effect on the heating load were the overall heat transfer coefficient of the covering material and the design outdoor temperature was next. The effect of the design values according to the number of spans showed little difference. In the case of the single-span greenhouse, the effect of the design values related to the underground heat transfer can not be ignored. However, in the case of the multi-span greenhouse, the effect of the design values related to the underground heat transfer and the infiltration rate were insignificant. The design values which have the greatest effect on the cooling load were the solar radiation into the greenhouse and the evapotranspiration coefficient, followed by the indoor and outdoor temperature difference and the ventilation rate. The effect of the design values showed a great difference between the single-span greenhouse and the multi-span greenhouse, but there was almost no difference according to the number of spans. The effect of the overall heat transfer coefficient of the covering material was negligible in both the single-span greenhouse and the multi-span greenhouse. However, the effect of the indoor and outdoor temperature difference and the ventilation rate on the cooling load was not negligible. Especially, it is considered that the effect is larger in multi-span greenhouse.

키워드

참고문헌

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