Nowadays, agricultural production is inseparable from greenhouses, which can not only resist natural disasters and droughts and floods.
It can also be cultivated earlier or later to extend the production cycle of crops and achieve the purpose of early maturity, late maturity, increased and stable yield.
Due to the different climates and purposes of use in different places, the specifications of greenhouse greenhouses are also different. The most important thing in the greenhouse is the covering material.
The common covering materials are toughened glass, PC board (polycarbonate), PE film, PO film, PVC film, and PVF film.
Toughened Glass
Pros:
1. High transmittance: 90% light transmittance goes through the glass to provide the highest sunlight to the crops inside the greenhouse.
2. Aesthetics: we can see through the glass from any view, the glass greenhouse is an eye-catching space anywhere.
3. High strength: toughened glass has a high surface strength of over 90MPa, it is stronger than polycarbonate or any other covering material.
4. Longevity: the toughened glass has no limit on service life theoretically, without outside impact or man-made sabotage.
5. Environmental friendly: there is no hazardous substance inside the glass. It’s easy to deal with even broken.
6. Everything Is Easy: glass is easy to buy, easy to install, easy to clean, easy to maintain, and easy to replace.
Cons:
1. Glass price is relatively high
2. Higher heating & cooling costs due to poor thermal insulation
3. Glass is heavy, has more rigid requests about the support structure
PC/Polycarbonate Board
Pros:
1. High light transmission: PC board light transmission rate of up to 89%, can be compared with the glass parents.
2. Impact resistance: impact strength is 250-300 times that of ordinary glass, the same thickness of acrylic plate 30 times.
3. UV protection: PC board is coated with anti-UV coating on one side and anti-condensation treatment on the other side, combining anti-UV, heat insulation, and anti-drip dew functions in one.
4. Lightweight: the specific gravity is only half that of glass, saving the cost of transportation, removal, installation, and supporting frame.
5. Flame retardant: PC board’s own ignition point is 580 degrees Celsius, self-extinguishing after leaving the fire, will not produce toxic gases when burning, will not contribute to the spread of fire.
6. Bendability: cold bending can be used to install into arches, semi-circular tops, and windows, and can also be hot bending.
7. Sound insulation: PC board has obvious sound insulation effect, and the sound insulation of PC board is 3-40DB higher than that of glass.
8. Energy saving: keep cool in summer and heat preservation in winter, PC board has lower thermal conductivity.
9. Temperature adaptability: The PC board does not become cold brittle at -100℃ and does not soften at 135℃, and its mechanics and mechanical properties do not change significantly in a harsh environment.
Cons:
1. Easy to get dust on the surface
2. Fast decay of light transmittance
3. Short life span of anti-dripping function
4. High initial investment
PE Film
Pros:
1. Up to 18 meters wide, more design options
2. Resistant to acid, alkali, and salt
3. Not easy to produce toxic gas, safer for crops
4. Not easy to stick to dust, good light transmission rate
5. Small density 0.92g/cm3, the low relative cost
Cons:
1. infrared transmission rate of up to 80%, poor insulation performance
2. poor strength, poor resilience, and easy to tear
PO Film
Pros:
1. Excellent transparency
It is made of high-grade olefin raw material, which has low haze and high transparency. High light transmission rate, low scattering rate, and will warm up quickly in the morning.
2. Superb defogging ability
The use of defogging and dripping agent coating and drying treatment can inhibit fog generation, and the defogging and dripping period can be synchronized with the service life of the agricultural film.
3. Reinforced thermal insulation performance
The film adopts a high-tech special organic insulation agent inside the film so that most of the infrared rays radiated from the shed to the outside are reflected back. It effectively controls heat dissipation.
4. Long service life
The use of high-tech antioxidants and light stabilizers greatly extends the service life of the agricultural film, which can reach more than 3 years with normal use.
5. Super Tensile Strength
The raw material has superb tensile strength and anti-tear strength.
6. Anti-static and non-sticky dust
Adopt nanotechnology with a four-layer structure. Anti-static treatment on the surface. Not easy to absorb dust, to achieve the effect of maintaining high light transmission for a long time.
7. Reduce pests and diseases, suitable for pollution-free vegetable production
PO film makes shed light enough, raises the temperature quickly, reduces the relative humidity, can reduce pests and diseases.
8. Increase yield and income
Good light transmission, high photosynthesis, high temperature, yield can be increased by 10-25%.
Cons:
Relative high price
PVC Film
Pros:
1. Colorless and transparent with high strength
2. Good heat preservation performance
3. Rainproof, fireproof, acid-resistant, anti-static
Cons:
1. easy to absorb dust, resulting in a significant decline in light transmission
2. low air and moisture permeability, less toxic gases through
3. will cause high temperature and high humidity indoor environment, harming crops
4. 50% higher cost than PE film
PVF Film
Pros:
1. High mechanical strength
2. aging resistance, can last 15 to 20 years
3. High light transmittance, almost no decay
4. High dust resistance on the surface
5. strong mist elimination and anti-dripping ability
Cons:
1. PVF contains fluorine, which is toxic
2. It needs to be recycled by the manufacturer for special treatment after use
3. Poor design, within 3 meters in width
