Articles
SIMULATION MODEL FOR BUOYANCY-DRIVEN VENTILATION FOR A GREENHOUSE COOLED BY A FOGGING SYSTEM
Article number
719_47
Pages
417 – 426
Language
English
Abstract
A feasibility study was conducted analytically, to evaluate an evaporative cooling system for greenhouses.
The system combined uniformly distributed high-pressure fogging nozzles above the plant canopy with natural ventilation, based on thermal effects, with uniform openings in the roof and in the lower part of the side walls.
In accordance with this setup, a computer model was established to calculate the required areas for the ventilation openings in the roof and in the side walls, as related to the greenhouse dimensions and the desired conditions in the greenhouse, and in accordance with the ambient conditions.
This model is based on the difference between the air densities inside and outside the greenhouse.
The results indicate that: (a) it is possible to establish conditions in the desired range during most seasons and in most parts of Israel; (b) natural ventilation based on thermal effects is very sensitive to wind disturbance; (c) the greenhouse length and/or width form a limiting factor(s); and (d) it is a complicated task to control such a system.
The system combined uniformly distributed high-pressure fogging nozzles above the plant canopy with natural ventilation, based on thermal effects, with uniform openings in the roof and in the lower part of the side walls.
In accordance with this setup, a computer model was established to calculate the required areas for the ventilation openings in the roof and in the side walls, as related to the greenhouse dimensions and the desired conditions in the greenhouse, and in accordance with the ambient conditions.
This model is based on the difference between the air densities inside and outside the greenhouse.
The results indicate that: (a) it is possible to establish conditions in the desired range during most seasons and in most parts of Israel; (b) natural ventilation based on thermal effects is very sensitive to wind disturbance; (c) the greenhouse length and/or width form a limiting factor(s); and (d) it is a complicated task to control such a system.
Publication
Authors
A. Arbel, A. Shklyar, M. Barak
Keywords
greenhouses, ventilation, buoyancy, evaporative cooling, fog
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