ISHS Acta Horticulturae 174: Symposium Greenhouse Climate and its Control
IMPROVED METHODS OF GREENHOUSE EVAPORATIVE COOLING |
| Authors: | G.A. Giacomelli, M.S. Giniger, A.E. Krass, D.R. Mears |
| Abstract:
The ability to cool greenhouse air is essential in growing many warm weather greenhouse crops. Present methods, such as fan-and-pad cooling are lacking in both the amount of cooling at high humidity and the uniformity or distribution of cooled air within the greenhouse. Two methods, a wetted overhead energy-saving blanket and fog nozzles on a movable boom, were devised and tested. The blanket (open weave, 55% shading) acted as an evaporative cooling surface when wetted by mist nozzles placed in the greenhouse attic above the blanket. Preliminary results have shown good to excellent uniformity as well as temperature reduction of up to 4°C. The fog produced by nozzles on the movable boom showed a greater evaporation rate, especially at higher humidities. Temperature reductions of up to 10°C have been achieved. The optimal combination of water flow rate, ventilation air flow rate and boom speed were found for various environmental conditions. Results to date show that temperature uniformity improves at higher air flow rates but it is not effected greatly by boom speed. | |
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