Essential Elements That Influence the Efficiency of Greenhouse Mechanical Ventilation Systems

plants inside a greenhouseGrowers can choose to invest in a greenhouse to extend their planting season or protect their seedlings in their early growth stages. Several elements determine the efficiency of your greenhouse. One of these elements is the ventilation. Your greenhouse’s ventilation primarily controls humidity, temperature and oxygen/carbon dioxide exchange and improves air circulation.

Your commercial greenhouse builder at Conservatory Craftsmen might opt for mechanical rather than natural ventilation. Mechanical/active ventilation uses fans and gives you better control of your greenhouse conditions and higher yields compared to natural ventilation. Here are the primary elements which influence the efficiency of mechanical ventilation systems.

Fan Sizing

Experts generally recommend a 10-feet height for fans used in greenhouses which operate all-year-round. The rule of thumb used in fan sizing is to multiply this 10-ft constant height with your greenhouse’s length and height. The product of this calculation is the cubic foot/minute capacity of the fans required to cool your greenhouse.

Fan Location

Your greenhouse’s exhaust fans should be placed on a wall opposite your intake vents to enable the flow of air over your plant canopies and throughout your greenhouse. Your builder might recommend setting up the fans to work with your area’s prevailing winds. This improves the efficiency of your mechanical ventilation system by up to 20%.

Static Pressure Difference

Air enters your greenhouse owing to the structure’s lower static pressure compared to the outside. You should maintain a constant static pressure difference between the outside and inside of your greenhouse to ensure unhindered airflow. The ideal static pressure difference in most greenhouses is about 0.05-inches of water measured using a manometer.

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The precise location and sizing of your fans and the greenhouse’s static pressure are primarily dependent on climate changes. Your greenhouse builder will hence assist you in getting the exact figures for your greenhouse for different seasons. He/she might recommend variable speed fans that can be turned down in winter and up in summer to boost their energy-efficiency.