Products

Characteristics of polycarbonate as a greenhouse cover

1) It retains heat twice more than polyethylene sheet.
2) Transmits 90% of light.
3) Its pressure tolerance is 200 times that of glass.
4) Its thermal and electrical resistance is high.
5) It is resistant to dilute mineral and organic acids, oxidizing and reducing agents, acidic and neutral salts, oils, fats, alcohols, and aliphatic and cyclic hydrocarbons.
6) It has excellent impact resistance in the temperature range of 42 to 802 degrees Celsius.
7) Its weight is one-sixth of a glass.
8) Checking the water due to its low moisture density.
9) It can be cut, sawed, drilled and nailed.
10) It has an ultraviolet ray preservative and is long lasting (some types last at least 10 years)
11) Its fire resistance is much higher than polyethylene sheet (plastic).
12) Double-layer types are good insulators and reduce heat loss by 50% compared to single-layer glass.
Polycarbonate sheets are produced in transparent or matte colors or simple or multi-walled sheets. Meanwhile, multi-wall, single-wall, and single-wall shutter sheets are used as greenhouse covers. Multi-wall sheets are produced in the following dimensions:
• Thickness 4-6 mm, double-walled
• Thickness 8-10 mm, double-walled
• 16 mm thickness, triple wall

Double-walled polycarbonate sheets, as well as its thick shutter type, are currently very popular for covering the greenhouse. The double-walled type, which is suitable for covering the walls, has a price almost equivalent to glass, but the shutter type, which is very suitable for covering the roof of the greenhouse, is more expensive. Glass is more expensive, although polycarbonate has less heat transfer capability than glass and reduces energy consumption costs, but it has less light transmission capability than glass. Also, due to the permeability of the empty space between the two walls, it starts to become cloudy after a while and its ability to transmit light is reduced again, of course, if the polycarbonate sheets are not installed and sealed properly and moisture enters the empty space between them. It creates a suitable environment for the formation of all kinds of pests. Also, the service life of polycarbonate sheets is less than that of glass, obviously, taking into account all aspects and especially the primary and secondary costs, polycarbonate coating is a more suitable coating than glass for commercial greenhouses, where profitability is the first priority. Commercial greenhouses use polycarbonate to cover the walls and plastic to cover the roof in order to save initial costs. But in educational research greenhouses where the quality of execution, better sealing, longer life and easier operation are more important, at least for covering the glass roof, it is considered a better option than double-walled polycarbonates.