Greenhouse engineering is a comprehensive project, and its cost depends on the structural form, covering materials, configuration of auxiliary equipment and construction and other factors. For some of the above-mentioned contents, there are also good or bad quality and high or low price points. Therefore, before ordering, we must first locate the greenhouse functions and grades that we need, and then make inquiries, comparisons, and final selections with the various greenhouse suppliers. Buy a product with a superior price/performance ratio. The following is a brief introduction to each item. First, the structure part a. Structural form The greenhouse structure is an ultra-lightweight steel structure. According to the requirements of the covering material, four types of arches, steel portals, herringbone, or V enlo (subtraction column method) are generally used. Because the amount of steel used in various structural forms is different from the difficulty of processing, its price is also different. Under normal circumstances, prices range from low to high. b. Material Because the current domestic greenhouse industry does not yet have industry standards, most greenhouse manufacturers are referring to foreign standards, but the overall requirements for structural steel must be cold-rolled steel with a yield strength of 235 or more. c. Processing and anti-corrosion greenhouse structure in a high temperature environment, coupled with the majority of structural steel are light steel, so the processing and corrosion requirements are more stringent. To sum up, there are the following requirements: (1) Surface anti-corrosion treatment Generally, hot-dip galvanizing or zinc-spraying and anti-corrosion treatment (2) The joint treatment must be bolted or riveted to avoid welding. Due to the change in the material of the steel after welding, even if it is hot-dip galvanized, it will easily fall off, and as a result, the corrosion will eventually lead to structural damage. (3) All processing and anti-corrosion treatment in the factory can no longer be carried out on the spot, and welding or cutting will not be able to carry out anti-corrosion treatment. (4) Anti-drip Due to the greenhouse planting requirements, it is determined that there should be no dew under the planting area, otherwise the planting crops are prone to diseases and insect pests, which will affect the crop quality and economic efficiency. Therefore, in addition to the anti-condensation of the covering material, the structural part must have anti-drip Features. Second, cover materials boiled down The current cover materials used in greenhouse engineering can be divided into about three categories: (1) polyethylene functional film (longevity without drops) (2) pc board (polycarbonate sunlight board) (3) glass above The three types of covering materials are all set according to the planting requirements. The cost depends on several aspects such as quality, service life, light transmittance, heat preservation performance, impact resistance, etc. Users can specify various types of covering methods and materials according to their own conditions. No matter what kind of covering material is selected, the thickness, strength, aging resistance and life expectancy should be clarified in order to obtain a good price performance ratio. Third, ancillary equipment (1) shading In general, the customer needs to set different shading functions according to the needs of growing crops, at present, most greenhouses use the following shading methods: a. Inside shading b. Outside shading c. Inside and outside shading and other three ways. The main purpose of the separate external shading is to control the light, generally using black plastic woven fabrics; the internal shading is also considering the heat preservation function while considering the lighting control, generally adopting the aluminum foil braid, preventing the indoor heat from radiating to the outside at night or in winter, and reducing the greenhouse Operating energy consumption; internal and external shading, external shading for light control, using black plastic weaving curtains, the main consideration for internal shading insulation, generally non-woven fabrics. (2) Ventilation and ventilation methods are mainly natural ventilation and forced ventilation. Natural ventilation is generally used a. Skylights, skylights and side windows; b. Roof roll film and side window roll film. The first form has the advantages of robustness and durability, but the one-time investment is larger; the second form has the advantages of one-time investment, but due to its structure, there are disadvantages such as poor greenhouse sealing, plastic film damage and poor wind resistance. Forced ventilation generally adopts two forms of fan and side window or curtain. The fan and side window use the principle of convection. Generally, the temperature of the greenhouse can be brought close to the outdoor temperature, but it cannot be lower than the outdoor temperature. The fan and the curtain must be matched. , The use of fans to vent the air outside the room to form a negative pressure, so that the outdoor air through the curtain, while the water vapor absorption of heat molecules, so as to achieve the purpose of cooling. (3) Cooling and cooling methods are as follows: a. Ventilation b. Visor c. Water curtain and fan d. Fog cooling and so on. The first three have been discussed. The fourth principle is similar to the cooling of water curtains. It also absorbs air heat through vaporization of water molecules to achieve a cooling effect. Because of the higher requirements for water quality and pressure, it must be accompanied by water treatment equipment and high-pressure pipelines. The humidity in the greenhouse is too high. Currently, most greenhouse users do not use it. (4) Insulation and heating construction The greenhouses shall be equipped with insulation and heating functions according to different climatic conditions. These two functions determine the size of greenhouse operation costs, especially in the northern regions, which mainly depends on the coverage forms and materials. Currently, internationally popular methods are Try to improve the tightness of greenhouses. At the same time, try to use materials with low thermal conductivity as much as possible, or try to avoid direct heat loss in the way of covering. Such as: double inflatable membrane, hollow sun plate or double non-woven fabric shade insulation screen and other forms. Heating methods are determined by the composition of the domestic energy structure. Currently, plumbing is the cheapest heating method. The use of plumbing requires a heat sink. Because the characteristics of greenhouse cultivation determine that the radiator must be uniformly cooled, the radiators used in most greenhouses are round. Airfoil radiator. In order to ensure the same temperature in various points in the greenhouse, or to achieve regional control, but compared with the traditional cast iron radiator higher prices, one-time investment. In the southern region, the use of oil-fired hot air stoves is more commonly used, which has the advantage of a small one-time investment but a large operating cost. (5) Irrigation and fertilization According to production needs, the general greenhouse is equipped with three forms of drip irrigation, micro-irrigation, and sprinkler irrigation, which can be individually configured according to different requirements (such as drip irrigation for vegetable cultivation) and can also be mixed in various forms. Configurations, such as flowering or nursery, can be combined with liquid fertilization systems. Gasification can use bottled carbon dioxide or carbon dioxide generators. (6) Fill light system The fill light system mainly considers that when the light is insufficient, in order to strengthen the photosynthesis of plants, artificially fill light. This function depends on the climatic conditions or the need of planting crops. (7) Production form a. Soil cultivation b. Soilless cultivation (substrate cultivation, hydroponic NHF or DHF). Users can choose different cultivation methods according to the product type, but they must be explained when ordering the greenhouse in order to design a reasonable configuration. (8) The control system control mode depends on the user's needs and can be automatically or semi-automatically controlled. The automatic control can be divided into computer control, single board control and programmable controller control. Semi-automatic control mainly adopts combination of programming control and manual control. Different control methods have different construction costs. Users can choose their own way according to their needs. However, depending on the function setting, the higher the level of intelligence, the higher the cost.
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