溫室蒸發冷卻系統降溫效果量化指標之建立

Quantitative Measures of the Effectiveness of Evaporative Cooling Systems in Greenhouse

方煒(Wei Fang)

《農業機械學刊》 4卷2期 (1995/06) Pp. 15-25

https://doi.org/10.30062/JAM.199506.0002

摘要

採自然通風或强制通風方式降溫的溫室皆不可能使溫室內氣溫降至大氣溫度以下。蒸發冷卻法為進一級之可行選擇，常見者有風機濕簾法、風機水霧法及風機微霧法等三種。風機濕簾法簡稱水牆法為應用最廣，但是水牆效率常被誤認為就是水牆系統之效率，其實不然。另外，效率為100%的噴霧系統仍然不能將溫室溫度降至同於外界之濕球溫度的現象也常讓許多人不解，此些錯覺之答案皆與所謂「效率」的定義有關。本研究探討各種蒸發冷卻方法之效率，推導新公式以重新定義新名詞並犛清觀念上容易造成混淆之疑點。在水牆系統方面，包括闡述水牆效率與水牆系統效率之不同，水牆系統「適用性」計算公式之導出，水牆系統「降溫極限」計算公式之導出及定義水牆系統之「有效性」。在噴霧系統方面，包括噴霧系統「理論降溫度數」計算公式與「噴水量理論極限值」計算公式之導出，最後並探討噴霧系統之效率、可用率及有效性。

關鍵字

溫室 ； 蒸發冷卻 ； 效率 ； 有效性

並列摘要

It is not possible to have a greenhouse temperature lower than ambient temperature by using natural or forced ventilation along. Evaporative cooling methods such as ”Fan and Pad”, ”Fan and Mist” and ”Fan and Fog” are some better choices for greenhouse cooling. ”Fan and Pad”, also termed ”wetted wall system”, is popular in controlled environment agriculture of Taiwan. Nevertheless, the terms for pad(wetted wall)efficiency and system efficiency were somehow confused. Also, many people can not understand why a greenhouse with nozzles having 100% efficiency fails to bring the temperature of the house down to the outdoor wet bulb temperature. All these misunderstanding were all originated from the definition of the term ”Efficiency”. This study tried to reinvestigate the efficiency of the three evaporative cooling systems and the efficiency of its' components. First, focussing on the fan and pad system: equations for the calculation of the suitability and the lowest temperature that the system can achieve were developed. The effectiveness of the fan and pad system was also defined. Secondary, focussing on the fogging system: equations for the calculation of the theoretical amount of temperature that can be reduced and the maximum amount of water required by a fogging system were developed. The concepts of efficiency, availability and effectiveness of a fogging system were also introduced.

並列關鍵字

Greenhouse ； Evaporative Cooling ； Efficiency ； Effectiveness