Feasibility evaluation of the ventilation control mechanism drive of a large screen canopy

Abstract

The study was carried out on how to enhance the effectiveness of solar energy and reduce technological risks connected with growing large-fruited tall tomato varieties in conditions of insuffi cient heat supply by using automatically controlled infl ow-and-exhaust ventilation. High probability of late recurring and early autumn frosts in Western Siberia poses a threat of complete harvest loss of thermophilic vegetable crops. Improvement of the heat supply during the growing period is possible due to the greenhouse effect occurring in canopies and greenhouses. In summer, additional energy creates the danger of overheating, which can be eliminated by an automatically controlled infl ow-and-exhaust ventilation. Laboratory experiments showed that the automatic device consistently maintains air temperature within 26-27°C, which meets biological requirements of plants, by changing the width of the exhaust air aperture. Opening of the infl ow air aperture increases the intensity of air fl ow inside the canopy. The hydraulic drive of the ventilation control mechanism consistently maintains the air temperature inside the canopy in the process of heating by means of automatic regulation of exhaust air aperture width, but it is ineffective in the cooling process due to high thermal inertia. Changing the height of the infl ow air aperture from 0 to 0.3 m makes the intensity of air exchange increase and the air temperature decrease.