Posts

Why it’s worth to replace greenhouse screens on time

Often, growers wait far too long to replace their greenhouse screens. Understandable, since it’s a major investment. However, changing your greenhouse screens on time offers many advantages, which are often noticeable in the very short term. We name the four most interesting advantages.

Higher energy savings

The most important reason to replace screen material on time, is energy saving. The horticulture industry is very innovative, and producers of screen material keep on developing as well. Therefore, the fabric of new screens has better energy saving aspects than the types of screen material that were available 5 to 10 years ago.

Better light output

New screen material is free of dust and dirt and therefore clearer. This results in a better light output when the screens are closed. This is especially important with energy screens. The screens can stay closed for a long period, which will benefit the light output. Recently, a Dutch grower found out what difference new greenhouse screens can make: compared to the old screens that were installed 10 years ago, the new screens delivered 40 PAR more light (of the 80 PAR needed).

 

We help avoiding fines related to light pollution

From September till April, the Netherlands and Belgium experience a light restriction period. In the Dutch Westland, but also in other areas and countries,  greenhouses are strictly monitored for compliance with the rules regarding exposed crops. Make sure both horizontal and roller screen installations are in good shape. In that case, there’s no need to worry about the rules that apply to light emission.

Flame retardant properties

Since 1 January 2017, Dutch insurance company Achmea Agro demands flame retardant screens and foil in Dutch greenhouses. As per 1 January 2010, they only accept companies that have flame retardant screen material installed. Other insurance companies set the same requirements. All screen material installed by Holland Scherming, are applicable to the NTA 8825 standard that is used by insurance companies.

Do an inventory now, replace during less hectic periods

Of course you´re not waiting for your screens to be replaced at the peak of your production. However, it is wise to think ahead. Only then, before your next production cycle starts, you will have a screen installation in optimal condition. A first good step is an inventory of the work that needs to be done. So make an appointment now with one of our sales consultants for a free inventory.

High energy savings with the use of super-insulation screens: Kas als Energiebron

Wageningen University (WUR) published a new report on greenhouse screening. WUR has done research on the use of high insulation screens at cucumber cultivation. The test results are very promising; in comparison to a normal greenhouse with a single energy screen, 44% less energy was used to heat the greenhouse from January till May.

As an installer of greenhouse screening, Holland Scherming notices a growing demand for double greenhouse screening. More and more growers discover the advantages of the new cultivation (HNT) and adapt their greenhouse screening systems.

 

csm_kk_proef.JPG_scherm_0318b2ce8c

 

Research abstract

In 2014 a greenhouse experiment was executed with a high-wire cucumber crop to measure the impact of a
multiple layer system of energy screens. The screen systems that have been tested were:

  • 2 layers of aluminized cloth with a 5 cm cavity operated by a single sliding system closed all night.
  • 1 layer of high transparency, non-porous PVDF film on a second sliding system, closed all night and when heating was required, usually below an outside radiation level of 150-200 W/m2.
  • 1 layer of perforated transparent PE film, mounted alongside the double screen, closing as soon as the double screen opened and opening above an outside radiation level of 100-150 W/m2 to reduce the PAR light losses.

The result was a 44% reduction in heating energy in the period of January to May compared to a glasshouse with a single energy screen. Production and product quality were comparable. The intense use of screens influenced the greenhouse climate. Plant temperature remained high because the radiation losses were limited. Since the opening and closing of the screens were very gradual, no shocks in plant temperature or vapour deficit occurred. This greatly reduces the risk of condensation on the leaves leading to botrytis or to a sudden drop in transpiration leading to plant cell damages. This test shows the positive effects of a highly insulated greenhouse and the chances to regain sensible and latent heat comprised in the ventilation losses of transpiration.

 

Portfolio Items