Ventilation is also used to prevent excessive humidity due to perspiration from the culture. This control is performed in order to prevent disease.
Humidity excess occur in cold periods, and its effect is more pronounced during changes from night to day.
Humification Systems
At low relative humidities, humidification systems are installed, the operation is also likely to be used to lower temperature, provided that the difference in the moisture content of outside air is appreciable relative to the interior.
From the control point of view, at least two relative humidity thresholds are set, for one for night and another one for the day, in accordance with the setpoint established for assigning each temperature curve with permissible moisture deficits maximum and minimum gr / m3, or relative humidity (curve Mollier).
Ventilation Installation
If humidification system is not used, the control of relative humidity is performed by installing ventilation. For this purpose it is operated according to two guidelines:
- If the relative humidity is below to the set point established, the opening degree of ventilation will decrease
- And if the opening is higher, it will increase.
Ventilation + Heating
The combined use of heating and ventilation, is used to force perspiration on cloudy days where the temperature difference between the outside and the inside is small. This practice is often done in greenhouses in northern Europe, even in summer, despite the energy which contracts, in order to maintain a minimum moisture deficit.
