Single Tunnel Greenhouse Project Description

Single tunnel greenhouse also called hoop greenhosue, solar greenhouse or poly greenhouse, here introduce it for you 

1. 

1. Project Aim

1.1 Principle

① Adhere to the principle of scientific, advanced and practical combination, taking into account the actual use of greenhouse function, reasonable selection of appropriate supporting equipment, achieve a good price performance ratio.

② Adhere to the reality, reasonable determination of design standards, production technology, main equipment and projects to achieve advanced, applicable, reliable.

③ Adhere to the principle of local conditions, focus on local climate conditions and cultivation requirements to design.

1.2. Greenhouse design basis

①  Relevant greenhouse standards.

②  The current national design and construction code and equipment requirements for building structures.

③  Actual use function of greenhouse.

④  Basic meteorological data of the project site.

2. Main parameters and configuration

2.1  Greenhouse overview

According to the basic conditions of the greenhouse project and the requirements of the construction side, this project adopts the film single unit greenhouse, the appearance is beautiful and modern, the discharge and unloading wind is smooth, the structure is stable, and it is more suitable for the area with strong wind and light. Good shade, economic and suitable, suitable for crop cultivation, the top and around to be covered with 150um milk-white film.

Greenhouse basic configuration: high-quality hot-dip galvanized skeleton, cooling system, electric control system. According to the basic conditions of the greenhouse project and the requirements of the constructor, it is used for crop cultivation.

2.2 Greenhouse specifications

Thin film single greenhouse span 9 meters, length 39 meters, top height 3.2 meters, edge height 1.2 meter, around brick wall skirt height 0.3 meter. The arch rod adopts hot-dip galvanized elliptical tube, horizontal pull rod, vertical brace, shed head column, eight-character brace adopts Φ32*2.0 hot-dip galvanized circular tube, string tube is Φ25*2.0 round tube.

2.3  Characteristics of the film Single Unit Greenhouse

① Strong ability of temperature regulation, which can provide good crop growth and comfortable leisure environment.

Advanced and complete ventilation facilities, ensure that in summer when the temperature is high, can quickly cool down, dehumidification; winter when the temperature is low, to ensure the appropriate indoor temperature throughout the year.

②Reasonable structure, high strength, neat appearance and beautiful appearance.

Reasonable structural design to ensure that the greenhouse has enough wind and rain load resistance, to ensure the appearance of the greenhouse neat, beautiful, but also to ensure the heat insulation, insulation performance.

③Performance-price ratio is high, and daily use, maintenance costs are more lower.

The basic configuration of thin-film multi-span greenhouse is: high-quality hot-dip galvanized skeleton, fan, water curtain cooling system, electronic control system. According to the basic conditions of the greenhouse project and the requirements of the constructor, the greenhouse is used for crop cultivation.

Reasonable design, as far as possible to use natural conditions or low energy consumption equipment to adjust, improve the environment inside the greenhouse, reduce the overall cost of greenhouse; also greatly reduce the daily operating costs of greenhouse. The rational use of high quality products in the key parts of greenhouse will not obviously increase the overall cost of greenhouse while improving the performance and reliability of greenhouse, greatly reduce the accidents in the use of greenhouse, and reduce the cost of daily maintenance.

3. Film multi-span greenhouse foundation and main skeleton

3.1 Greenhouse base

Considering the factors of heat preservation, economy and beauty of greenhouse, according to the requirements of soil endurance, groundwater level and design load, to avoid uneven settlement of greenhouse, to prevent column distortion and shear deformation ,240 mm of reinforced concrete ring beam is used around the greenhouse. Outside the wall skirt to do 0.5m wide scattered water, gable plus drainage ditch, foundation buried depth of 1.0 m( tentative, according to the actual situation value is greater than the thickness of frozen soil layer). The indoor column of greenhouse adopts 220*220 mm reinforced concrete independent foundation, the buried depth of foundation is 1.0 m( tentative, according to the actual situation), the top of the foundation is pre-buried steel plate or anchor bolt, and the upper steel column  welded or bolted. The elevation of the embedded parts on the strip foundation and independent foundation is 5‰; in the north-south two-way looking for slope, reference to the detailed in the elevation schematic in the foundation plan.

Geological data: this design foundation bearing capacity standard value fka≥100kPa, after the construction slotted must be by Party A, the construction unit and the local geological department in accordance with the relevant construction code inspection slot, if not in accordance with the design must notify the relevant designers to negotiate to resolve.

3.2 Major structure

The main steel structure of greenhouse adopts double-sided hot-dip galvanized pipe and profile, the service life is 20 years. The main structure adopts the form of circular arch. Galvanizing method adopts the international general " advanced Sendzimir method" continuous hot dip galvanizing. The raw material is cold rolled strip, which is better than hot rolled steel in terms of mechanical property and anti-corrosion property. Among them, excellent mechanical properties ensure the overall carrying capacity of greenhouse, and the strengthening of anti-corrosion capacity is the guarantee of the overall life of greenhouse. The main steel structure is all the company's standardization, industrial production (including small connectors, accessories), improve the main greenhouse standardization degree, avoid different parts of the greenhouse using different external manufacturers of products, make the assembly unreasonable, directly lead to the overall structure of greenhouse stability decline phenomenon. With the latest anti-corrosion technology (Dacromet coating) treatment of bolts and self-tapping screw connection, no solder joints. The greenhouse skeleton adopts domestic famous hot-dip galvanized steel tube plate.

4. Greenhouse cover materials

 Greenhouse top and around covered with 150um milk-white film, anti-drop, quality assurance for 5 years.

4.1 Characteristics of milk-white Film

Milky-white protective film: the application of high resistance and water-proof coating liquid, with good barrier, to prevent the protection of the object and deterioration, sticky, with good adhesion with good performance of blocking water vapor.

4.2  Reinforced flame retardant thermal insulation

High-tech special organic flame retardants are used inside the film, and the high-resistance water-insulating coating solution is used. ensure the growth temperature of crops and shorten the maturity period.

5. Wet curtain-Fan cooling System

5.1 Wet Curtain

5.1.1. Design Principle: the cooling system of fan-wet curtain uses the principle of water evaporation to achieve the purpose of cooling. The system selects the domestic (Munters- https://www.munters.com) high quality wet curtain paper and the domestic water pump system, the domestic low pressure large flow fan. The system has the advantages of simple structure, low cost, low energy consumption, large cooling capacity and reliable operation. The cost of the equipment is only one seventh of the air conditioning, and the operating cost is only one tenth of the air conditioning. The core of the cooling system is a wet curtain that allows water to evaporate. Wet curtain is a paper product, in the long-term unworking state, very dry and brittle, only when the work contact with water to become elastic and hardness. In addition, inside and outside the wet curtain  High gas quality, no heat preservation effect, special polymer material and wood pulp fiber inter-molecular double space correlation, and high water resistance, weather resistance material cement, high cooling efficiency, long service life, small resistance loss. it not only ensures sufficient wet stiffness, high water resistance, but also has a large evaporation surface area and low over-current resistance loss. The special water conveyance wet curtain can ensure that the whole wet curtain wall is evenly wet with water. When the air penetrates through the wet curtain medium, the water-air exchange with the wet curtain surface converts the air sensible heat into vaporization latent heat, and realizes the humidification and cooling of the air. The following figure shows the example:

This system is set up in the closed greenhouse, when the fans are running, the indoor negative pressure is produced, forcing the outdoor unsaturated air to flow through the surface of the porous wet curtain, and a large amount of sensible heat in the air is converted into latent heat, thus forcing the dry ball temperature entering the indoor air to be reduced by 8~12℃, and continuously introducing the indoor to prevent heat and reduce the temperature.

5.1.2. Technical requirements 

（1）The wet curtain device shall be manufactured in accordance with the drawings and technical documents approved by the prescribed procedure;

（2）Wet curtain size, the use of plates and fittings and other materials in accordance with relevant standards;

（3）The design of evaporative cooling heat transfer efficiency and overcurrent resistance loss under wind speed should be in accordance with the provisions of table 8; table 8 design evaporative cooling heat transfer efficiency under wind speed and overcurrent resistance technical parameters evaporative cooling heat transfer efficiency E(%)70 overcurrent resistance (Pa1.4. wet curtain installation wet curtain inside wall of greenhouse. The greenhouse for planting is generally required to be installed on the north side of the greenhouse, the fans are installed on the south side, and the fans are relatively low in the shade of the wet curtain, which is beneficial to the crops. In areas with strong summer how winds/air, wet curtains may also be considered for installation on windward walls. In addition, according to the instructions of Party A Install with requirements. The main factors that determine the installation position of wet curtain are the shading of crop angle, the blocking of human visual angle, and the beauty of wall layout.

5.1.3 Wet curtain fixed frame water supply and drainage: domestic greenhouse wet curtain special frame, wet curtain water collection should be smooth. The upper water pipe and drain pipe are connected with the wet curtain frame with special connectors 8.1.6. Wet curtain outer window: use electric side flip window. 1.7. Basic configuration

1) Wet curtain :10 cm thick 1.5 m high, total length 20 m long aluminum alloy frame finished water curtain set.

2) pump: a total of 1,6 m3/unit, water supply, pump motor power 1.1 kw/unit.

3) water supply device :1 set of UPVC pipe ,ф32mm upper pipe.

4) backwater unit 1 set U PVC pipe ,ф75mm backwater pipe.

5) circulating pool 1, length 2 m× width 2 m× depth 1.5 m, placed in greenhouse. Part of the fan installation: the fan placed on the wall opposite the wet curtain, in order not to affect the lighting, the south wall fan, the north wall wet curtain. According to the greenhouse plant root ventilation needs, fans generally sit on 600 mm brick wall. Due to the strong outward exhaust of the fan, the air flow may blow to the passing crowd at the outdoor fan, and the height can also be raised for placement. In practical experience, the convection distance of the wet curtain of the fan is less than 6 meters. The total number of fans in this scheme is 4 meters, Exhaust fan size 1380×1380×400mm, air volume 44000 m3/h, single phase 1.1 kw.

6. Greenhouse Power Distribution System

6.1   System object

Greenhouse suitable for greenhouse

production or viewing.

6.2  System function

Control of cooling system 

(wet curtain-fan);

6.3 Technical parameter

Power parameters :220 V/380V;50HZ, scope range of the fluctuation of voltage ±5%.

For the area with large voltage fluctuation, the user is required to configure the voltage regulator before the entrance of each strong electric cabinet to ensure the safe operation of the electric appliance in the greenhouse.