Greenhouse Shading Net

The curtain of the internal shading system is an aluminum foil shading net, and its light transmittance is divided into 65%, 75%, 85%; its main function is to shade

The biggest advantage of the multi-span greenhouse is that it has high land utilization and improves the work efficiency of factory operation. There are both advantages and disadvantages. The largest energy consumption of multi-span greenhouses in the north is in winter. In order to achieve winter production, heating and heating equipment is inseparable. No matter how it changes, the traditional methods of burning boilers, natural gas, and electricity will all Increased operating costs

Before determining the heating method, the interior of the greenhouse must be well insulated to achieve the best insulation effect. Generally, 5+6+5 double-layer insulating glass is used around the glass greenhouse. The 16mm (5+6+5) insulating glass starts to condense when the outdoor temperature is -2°C, while the top 5mm single-layer glass starts to condense when the outdoor temperature is 8°C. The heat transfer coefficient of glass is 27 times that of air. As long as the hollow layer of insulating glass is sealed, the glass will have a good heat insulation effect. This is why it is recommended to use double-layer hollow solar panels on top in cold regions. At present, the method of enhancing the thermal insulation effect of the glass greenhouse is to add a set of inner thermal insulation quilt parallel to the inner shading net on the top of the lower part of the truss beam (waterproof and lightweight, the general square meter weight is 120g-150g). The function of the thermal insulation quilt is to separate the lower space of the glass greenhouse from the upper space. Avoid heat dissipation from the inside of the greenhouse to the outside through the top. At the same time, the walls of the greenhouse can be installed with thermal insulation quilts, mostly in the form of segmented roller shutters or zippers.

First, the difference between internal shading and internal insulation

The internal shading system can improve the ecological environment in the greenhouse by adjusting the light. When the indoor temperature rises to a certain value in summer, it can reflect part of the sunlight according to different shading rates, and diffuse the sunlight into the room to achieve the purpose of cooling. Closing the shading and thermal insulation curtain can reduce the temperature of the greenhouse by 4~6°C, so as to reduce the temperature required in the room.

Internal thermal insulation system When the greenhouse or indoor temperature drops to the set low temperature limit at night, the lightweight silk cotton thermal insulation quilt is turned off to strengthen the thermal insulation of the greenhouse, reduce the loss of radiant heat from the ground, reduce heating energy consumption, and greatly reduce the operating cost of the greenhouse. ; In the daytime, the lightweight silk cotton insulation quilt can be opened to make the greenhouse fully illuminated.

The transmission mode of the two is the same, both adopt the transmission form of rack and pinion or steel wire and cable, and the curtain or light silk cotton insulation quilt walks in the direction of the bay. The drive shaft is connected with the deceleration motor and the gear. When the deceleration motor rotates, the drive shaft drives the gear to rotate. The rotation of the gear drives the walking of the rack, and the push-pull rod is supported by the support roller and connected with the rack, so if the deceleration motor reciprocates, the push-pull rod can realize the reciprocating operation. One end of the sunshade net is fixed at the beam column, and the other end is fixed on the push-pull rod, so that the curtain or the light silk cotton thermal insulation quilt can be unfolded and folded.

2. The same point of the inner shading system of the multi-span greenhouse with the inner insulation system

Similarities: Both have the same drivetrain;

The components and working principle of the transmission system:

(1) Transmission mechanism: special reduction motor, rack and pinion drive, driving rod, transmission rod; the motor drives the transmission shaft to run through the transmission mechanism, the transmission shaft drives the driving rod to move in parallel on the curtain wire through the connecting piece, and the driving rod pulls one end of the curtain slowly Unfold, touch the travel limiter switch after all unfolds, the motor stops, and the stroke operation ends.

(2) Curtain support line: The curtain support line is a kind of plastic steel wire installed between the beams to drag the curtain. The curtain line is divided into upper and lower layers, the spacing of the lower layer is 0.5 meters, and the spacing of the upper curtain line is 1 meter.

3. The difference between the internal shading system and the internal thermal insulation system

(1) The curtain of the inner shading system is a kind of aluminum foil shading net, and its light transmittance is divided into 65%, 75%, 85%; its main function is to shade. The inner shading net automatically expands the inner shading net through the motor transmission system to reduce the intake of sunlight.

Fourth, the heat loss in the greenhouse

There are three main types of heat loss, namely through ground soil, cold wind infiltration and through the cover layer of the building envelope. The heat loss through the cover layer of the envelope structure is the main part of the heat loss in the greenhouse, which generally accounts for more than 60% of the total heat loss. Therefore, reducing this part of the heat loss is the focus of greenhouse insulation technology. The installation of corresponding greenhouse equipment or systems in multi-span greenhouses is a good way to improve the thermal insulation capacity of the greenhouse. It is one of the effective energy-saving measures to reduce the heat transfer of the greenhouse cover at night by increasing the thermal insulation cover. Inner thermal insulation lightweight silk quilt has been widely used in greenhouse production as an easy-to-install, easy-to-operate thermal insulation and energy-saving device. Expanding the inner insulation lightweight silk quilt can make the lower space of the greenhouse form a new closed system. The use of the lightweight silk quilt in winter has the following effects: reducing the heating space of the greenhouse; reducing the heat loss of cold air penetration in the greenhouse; reducing Radiation heat transfer between the greenhouse ground and crops to the upper space; increase the thermal resistance of convection heat transfer and reduce the latent heat loss caused by condensation of water vapor.

The film multi-span greenhouse is also a kind of large-scale production greenhouse, which occupies a large proportion in the actual flower production and vegetable seedling planting. The method of enhancing the thermal insulation performance in the northern region is to make the greenhouse into a double-layer film multi-span greenhouse, and the top and surrounding areas are made into a double-layer film style. Then a layer of internal insulation can also be added on the top.