The is a new controller under the bonnet of the greenhouse modeling program SIOM. This, according to Egon Janssen of TNO, allows the program to compete well with horticulturalists' own commercial controllers. The new version of the program also brings opportunities for growers, such as comparing two growing strategies.
It is one of the updates over the previous version. "One simulation takes 15 minutes. In this new version, it is possible to simulate 20 simulations at once for one whole year. For example, think of twenty temperature variations of 0.1 degrees Celsius each time. For next winter, when cultivation will be much more energy-efficient, such a simulation provides insights in advance about energy consumption and about the effects of a cultivation strategy on the plant." An under-the-hood improved crop evaporation model helps with this.
Comparison crop strategies in SIOM. Click here to enlarge.
More data for calibration
The new controller and the improved models under the bonnet of SIOM are a big step forward, says Egon, the greenhouse face of TNO to the outside. "We now have a system that allows every horticulturist to make a fair comparison between different technical solutions."
Yet work is already underway at TNO in Delft on the next step. The models within SIOM take a lot of things into account but not yet diseases and crop treatments, for example. For that reason, SIOM has been validated on some practical greenhouses. "Now that, thanks to the Hortivation Hub and Greenhouse Performance Monitoring, it is becoming increasingly easy to retrieve field data from a greenhouse, we can work towards validation tailored to the specific location."
What TNO is aiming for is that SIOM can eventually be validated with data from greenhouses of greenhouse builders affiliated with the Hortivation Foundation. "Every greenhouse builder wants to be able to do something specific, something different, with SIOM. Our goal is, therefore, to make SIOM as flexible as possible."
Click here to enlarge insight into a water cycle in SIOM
More users
SIOM is currently still mainly used by turnkey greenhouse builders, but TNO would like to see more and more other parties using it too. Together with the Hortivation foundation, it was therefore decided to also make SIOM available in an educational version for MBO and HBO further education courses. That way, the growers and greenhouse builders of the future can already use the possibilities of SIOM during their studies. "In doing so, they could, for example, calculate their strategy for a winter crop."
New updates
Meanwhile, new questions keep coming up to help improve SIOM. "Being able to compare different semi-closed systems is a wish," he says. A forthcoming update will provide a module that can quickly compare different scenarios. "That will come out in early 2023," Egon knows. "This will make it possible to determine what it has to comply with for the technology in the greenhouse. Think of questions like: How many degrees can a greenhouse heat up per hour at most? Or vice versa: How much should the maximum output of a heating system be?"
One important comment Egon would like to make, however. Despite all the technical innovations, it remains a model. "Very extreme strategies can be calculated, but because of the still limited set of practical data, the results are less reliable. It, therefore, remains necessary to keep using ordinary grower's common sense as well."
Photo right: greenhouse in Romania buried under snow
For more information:
Egon Janssen 
TNO
+31 (0)6 53 46 76 64
egon.janssen@tno.nl
www.tno.nl
Stichting Hortivation 
info@hortivation.nl
www.hortivation.nl