New inexpensive method for greenhouse dehumidification

Wageningen UR Greenhouse Horticulture has developed an inexpensive method to dehumidify the greenhouse under a high-insulating screen. The basis of this method is formed by the Ventilation Jet, a new ventilation system that brings dry air from above the screen into the nursery. The system was developed within the framework of the Greenhouse as Energy program.

Moisture control is a problem in greenhouses, more so when they are better insulated. In practice, several new techniques have been developed to decrease humidity with fresh air through a unit in the wall. However, these solutions are expensive. Together with suppliers, Wageningen UR Greenhouse Horticulture has developed a method that is simple and free of major investments.

Ventilation in screen

The Ventilation Jet is a system that consists of a vertical fan which is installed in the double screen, and below that a second fan. The Ventilation Jet brings air from above the screen down into the nursery. Because this air is cold, it is distributed horizontally and with the help of a second fan mixed with hot air from the greenhouse. The upper fan is operated on the basis of difference in absolute humidity above and below the screen pack. The lower fan is running when the screen is closed.

The Ventilation Jet not only contributes to saving energy in the greenhouse, but also to a more homogeneous greenhouse climate. This is an advantage, in particular for the illuminated crops. The capacity of dehumidification is easy to arrange through an on / off switch-controlled fan. There are several versions available.

Source: WageningenUR