Screens for Greenhouses
Each screen is personalized
The screening material has 3 major components: the shading degree, the thermal insulation degree and the permeability of the screen to the air currents.
The screen may differ according to:
- - The type of plants / crops
- - The role of the screen
- - The placement of the screen
- - The type of the screen, simple or double
1. The type of plants / crops:this aspect is important especially for the shading degree. The plants have different needs of shading, depending on their cultivation period or even on the plants themselves... some plants need full darkness.
2. The role of the screen:the screens can have the following types of roles:
- • Thermal screen – for saving thermal energy – the cold season. Only the part underneath the gutter is heated, thus resulting in important savings for the heating part (reducing the costs with at least 25-30%).
- • Shading screen – for decreasing the temperature – the warm season. During the warm periods the temperature within greenhouses and tunnels can rise over the comfort level of the plant. The shading screens can significantly decrease the temperature by 8-10 grade. They represent a very efficient cooling solution when combined with side openings or ventilators + walls with water curtains. The lettuce, for example, cannot be cultivated during the warm season without proper cooling.
- • Thermal & shading screen – a combined solution between the first two presented above… basically like all-season tires.
- • Opaque screen - generally used for certain types of flowers.
3. The placement of the screen:
- - Horizontal screen (most used)
- - Horizontal screen with flanked edges (which take on the curvature of the tunnel)
- - Vertical screen (on the vertical walls)
4. The type of the screen, simple or double:
The installation system allows for the screen to be double… meaning 2 rows of screens. The first row could be the shading screen and the second one could be the thermal screen. The double screen is of course the most expensive type, but it is the most versatile.
The price:the cost per square meter varies according to the surface, the type of the screen, the distance between arches, and it is between 5,5 euro/sqm and up to 20 euro/sqm.
Operating the screens:generally, the screens are operated by :
- - tube motors (220V) for screens placed on greenhouses / tunnels with one single module and a length of up to 50m.
- - gearmotors (220V or 380V) for screens placed on multi-modular greenhouses with lengths of up to 100m.
The automation using light sensor (shading screens) is optional. They are generally operated electrically, on-off.
Advantages of the screens, in short
- Save thermal energy
- Assure shading
- Decrease the temperature during the warm season
- Reduce the condensation (during the cold season, when there is excessive condensation created, the screens take a part of it.)