With ClearSpan, Alcomij introduces a new greenhouse concept developed from a concrete need in practice. In collaboration with Steur Advies and Van Amelsvoort Kassenbouw, a solution has been created that responds to the increasing complexity inside the greenhouse. The patented design forms the basis for a different approach to greenhouse layout.
Growers are placing ever higher demands on their greenhouses. Energy use, climate control and production need to be better balanced, while the number of installations and screen layers continues to increase. Where a single screen was sufficient for many years, it is now increasingly common to work with two, three or even four screens.
As Jeroen Noordermeer of Steur Advies explains, this is a logical development: growers are looking for more control over energy and climate, but are reaching the limits of traditional greenhouse layouts.
“Two, three or four screens are becoming increasingly common. The challenge is finding the space for them within the greenhouse.”
Until now, solutions have mainly been found by modifying the greenhouse structure itself. This increases complexity: columns are narrowed at truss level and trusses are fitted with additional screen supports. However, a fully integrated solution has been lacking.
This practical challenge led to the development of the Alcomij ClearSpan concept, in collaboration with Steur Advies and Van Amelsvoort.
A different way of using space
ClearSpan does not solve the problem by adding more space, but by organising the greenhouse differently. Screens are no longer positioned at the truss, but integrated higher up in the structure.
This immediately creates more effective growing space. The area below the truss remains available for crop and installations, offering greater flexibility in greenhouse layout.
At the same time, this positioning improves insulation. Integrating the screens higher in the structure creates a more effective separation between climate zones. This contributes to a more stable climate and a reduced heat demand.
Only then does the effect on light become apparent. Because the screens are no longer positioned in the direct light path, light loss is reduced. In specific configurations, this can result in up to approximately 2.5% additional light transmission*.
The result is a greenhouse where space, insulation and light are better balanced, without the structure limiting cultivation.
*Based on a configuration with 4 screens on an 8-metre truss, compared to a standard solution according to the IDT calculation method.
Practical advantages in the greenhouse
The strength of ClearSpan lies in the combination of effects. By integrating screens into the upper structure, the space below the truss remains available for both crop and technical systems. As a result, installations require less coordination and interfere less with each other.
According to Sven Fitters of Van Amelsvoort Greenhouse Construction, this offers a clear practical advantage: installations such as lighting and heating can remain where they are most effective, without restrictions caused by screen layers. At the same time, the principle remains intact that maximum light transmission is maintained, even when using multiple screens.
Clear benefits can also be seen at climate level. The higher positioning of the screens allows for better control of air layers within the greenhouse. Combined with the additional available space, this gives growers more control over their climate strategy.
As also emphasised by Steur Advies, the real gains are not only structural but are primarily found in cultivation performance.
Who is ClearSpan relevant for?
ClearSpan has been specifically developed for growers using multiple screens and actively managing energy use and climate. In situations where a single screen is sufficient, the added value is more limited. The improved insulation also makes the concept suitable within current sustainability subsidy schemes in greenhouse horticulture (SIG&F).
At the same time, the expectation is that the use of multiple screens will continue to grow across the sector. This is where the relevance of the concept lies: a greenhouse that not only meets today’s requirements, but also offers room for further optimisation in the future.
From concept to practice
The next step is practical application. Both Steur Advies and Van Amelsvoort Greenhouse Construction emphasise that a first project is essential to demonstrate its added value.
As Jeroen Noordermeer of Steur Advies summarises:
“The concept works, but you need to build it to truly demonstrate what it delivers.”
ClearSpan is therefore not just a concept, but a solution developed together with partners, focused on the daily practice of the grower.
