Growers want to save energy, but also have an optimal greenhouse climate as well as production and quality of their product. That is why they think it is still too early to step in on an additional energy-saving screen that is under development. One of the concerns is moisture in the greenhouse. More technical research needs to be done on this, according to a report by GLITCH researchers.
Growers are currently already using movable energy screens or energy screens. However, they do not always let enough sunlight through, also confirmed in research. In addition, higher energy savings are possible.
Moisture in the greenhouse. (GroentenNieuws Archive, Kom in de Kas 2019)
Climate neutral greenhouse
The new screen system, an 'Energy Balancing screen', consists of 2 types of screens: an EB day screen and an EB night screen. The EB day screens have a maximum light transmission so that sufficient sunlight radiates into the greenhouse.
With the EB night screens, the aim is to provide as much insulation as possible in such a way that the heat present remains inside the greenhouse and is not lost to the outside (= heat loss). An EB night screen system is a super-insulating greenhouse cover that allows the heating in the greenhouse to be switched off at night. The screens have to let moisture through or be used in combination with a dehumidification system.
When both Energy Balancing screen types are combined with a dehumidification system consisting of a vapour heat pump that dehumidifies the air and recovers heat, a climate-neutral greenhouse is created.
To achieve this, the material of which these EB day screens and EB night screens consist must be adapted so that the screens have a greater insulation value. In this way, the heat loss throughout the day is limited and an energy balance is obtained without the need for heating.
The researchers questioned tomato, pepper and cucumber growers in the Netherlands and Belgium about their willingness to work with the new screens. They did this in the period September 2019-November 2020. The growers were asked about the concept of the innovation.