It takes skill to apply AntiReflect properly
For AntiReflect to work properly, the thickness of the coating must be within a certain bandwidth. Only certified contractors are able to achieve this.
All ReduSystems coatings need to be applied with extreme precision. A uniform coating ensures a good outcome and prevents irregular light incidence in the greenhouse, which could result in an uneven crop or make the greenhouse climate harder to control.
“To achieve a uniform coating, everything has to be right: the spray pressure, the speed the spraying machine travels at, delivery from the spray nozzles, the weather conditions,” says Gert-Han van Hattem of HPW Spuittechnieken, a company that has been specializing in machine-applied coatings for 11 years. “In theory, you could do it all automatically, but we strongly recommend always having someone sitting on the machine to keep an eye on things and make sure the quality is consistent.”
More light
Applying AntiReflect requires even more precision than for ReduSystems coatings. This is due to the specific properties of the product. AntiReflect reduces reflection of light on the greenhouse roof, increasing the amount of light entering the greenhouse by about 3%. To achieve the optimum effect, the coating must be exactly the right thickness: between approx. 80 and 160 nm.
Van Hattem adds: “Achieving this thickness is not a problem for someone with the right experience. It can be done quite easily with a certain volume per hectare and the right pressure and speed of travel. What is tricky about this product is the fact that it is 100% transparent during application. You can’t see it at all, and that makes it harder to check what you are doing than with other coatings. You have to watch for very small bubbles on the greenhouse roof. So, you need to stay fully alert at all times.”
Certified contractors
Mardenkro certifies contractors that are able to apply AntiReflect in the correct way. To obtain certification, their system must meet certain requirements and they must demonstrate their ability to work with the necessary precision by performing a trial application.
Now, Mardenkro attends every application and the spray results are checked in the LightLab at Wageningen University & Research. Because of this working method, the area that can be applied in 2018 is limited to 200 ha. Mardenkro guarantees a light gain of at least 2.5%. In practice, the gain is well above 3%.
Installation of the spraying machine
Measuring light gain
Another important factor besides the method of application is the weather. “It should not be too cold, and it should stay dry for at least a day,” van Hattem explains. “In addition, the greenhouse roof needs to be thoroughly cleaned beforehand to ensure good adhesion of the AntiReflect. These aspects reduce the number of working days available and it will also take slightly longer because of the cleaning required. You can’t compromise on this: it has to be perfect. If you make a mistake, the entire greenhouse will have to be cleaned again before you can correct it. So, mistakes are costly.”
He adds: “I think it’s a good thing that Mardenkro actually measures the light gain; after all, it’s a product you can’t see. But it does work, my customers tell me. Their initial experiences have been positive: they really do increase their production.”
