At the EnergiekEvent in June, Delphy Improvement Centre researcher Stijn Jochems gave a presentation on screen strategies and their impact on the energy efficiency of lighted crops. In the presentation, he summarised the screen strategies applied in several demonstration crops and the insights from them. Most demo crops are under full LED, which presents new challenges compared to SON-T and hybrid lighting.
Kas als Energiebron (Greenhouse as Energy Source) shows that in several demonstration crops, which have taken place for several years in a row at the greenhouses of the Delphy Improvement Centre in Bleiswijk, the main focus is on lighting crops under full LED. This releases much less radiant heat than under SON-T or hybrid lighting systems. Stijn: "That affects the heat and moisture balance in the greenhouse and, therefore, also how to shade." The goal for energy-efficient Het Nieuwe Telen (The New Cultivation) is also to keep as much heat as possible inside the greenhouse with intensive screening.
Screens as part of the whole
The choices about the number of screens, type of clothes, and screening strategies differ from location to location and are related to the steering tools. In this respect, a number of shifts can be seen:
- SON-T and hybrid lighting are rapidly giving way to full LED installations.
- Growers are maintaining slightly lower heating lines due to high energy prices.
- The moisture balance deserves extra attention, especially when lights come on in the morning and crops start to evaporate more.
- Growers invest in systems that dehumidify greenhouse air.
- Growers are deploying more measuring boxes and sensors in multiple locations above the screen, above and inside the crop.
You can read more about screen strategies here at Kas als Energiebron.