The protection that the greenhouse roofing provides for the crops prevents harm caused by bad weather conditions outside - excessive insolation, low temperatures, heavy rain, strong winds, etc., but it also limits the renovation of air and slows its movement in the interior.

Air is employed in transpiration, respiration and photosynthesis. An appropriate rate of changing the interior air together with an adequate movement can provide optimum levels of temperature, hygrometric deficit and concentration of carbon dioxide uniformly throughout the volume of the greenhouse.

In Novedades Agrícolas S.A. we consider the importance of ventilation in a greenhouse very seriously, and we have built up the experience and know-how to supply and install the ventilation systems best suited to your greenhouse. Our technical department will evaluate the conditions of your greenhouse, the conditioning factors of your plants, and offer you the best solution for a productive unit with maximum guarantee of success.

Forced ventilation systems for destratification of the air:

The systems comprise a set of small helical fans distributed over the area of the greenhouse in different arrangements at a height above that of the crop. The objective of their operation is to generate small air currents that allow mixing and standardizing of the conditions therein. When the windows are closed, or the greenhouse air-change rate is low or zero, a small air current crossing the crop canopy substantially improves the exchange of gases, avoiding saturation conditions due to excessive humidity in low temperature conditions and improving transpiration under conditions of high temperature.

These systems are complementary to the operation of facilities for heating, misting, CO2 dosage, etc., with the objective of standardizing the temperature, humidity and concentration of carbon dioxide conditions.

A forced ventilation system for air destratification comprises:

• Destratification fans: Of the helical type, they have a tubular casing, blades and electric motor, with corrosion-inhibiting finish. They are designed to have a long range and a high flow rate.
• Speed regulators: They establish a “controlled” air current that produces a gentle vertical displacement that crosses the crop canopy.
• Electrification installation: Electric switchboards with circuit protection devices, starters, lines, electric conduits and the drive system for the set of the fans in the facility.
  

Forced ventilation systems:

The forced ventilation systems have, on one hand, a set of helical fans installed in a plane (sides or fronts of the greenhouse), usually working as extractors; on the other hand, working in combination, they have a doorway or window that controls the access of air.

This equipment allows each greenhouse to be provided with the appropriate ventilation rate for each case. The untreated external air circulates through the enclosure from its entry point to its exit evacuating the heat and transpiration load, thereby avoiding excessive temperature and humidity conditions.

This type of facility is suitable for replacing the operation of natural ventilation in greenhouses that do not have this type of installation, or which has different conditioning factors, guaranteeing the ventilation at certain moments when adverse environmental conditions arise for the crop. Combined with misting systems, or being an integral part of a set of evaporator panels, it offers the best results as regards its capability as a cooling system.

A forced ventilation system comprises:

• Extractor fans: they provide the sufficient renewal of the air volume housed in the compartment. They are usually fans of the helical type with shutter blinds, working in extractor mode.
• Air admission dampers: roll-up type window, tilting damper, etc., designed to control the access of ventilation air in combination with the operation of the fans. In some cases, the zenith ventilation system can be used for such an end by means of adjustment of its opening position.
• Electrical installation: electric switchboards, starters, lines and electric conduits and the drive system of the installation as a whole.

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