Definition
Greenhouse, also known as greenhouse. A facility that can transmit light, keep warm (or heat), and be used to cultivate plants. In the seasons that are not suitable for plant growth, it can provide greenhouse growth period and increase yield. It is mostly used for plant cultivation or seedling cultivation of temperature-loving vegetables, flowers, forests, etc. in low temperature seasons. The greenhouse can realize intelligent unmanned automatic operation, automatically control the greenhouse environment, and ensure the growth of cash crops. The data collected by the computer can be accurately displayed and counted. It can be automatically controlled into a modern planting environment.
Type
There are many types of greenhouses, which can be divided into the following four categories according to different roof truss materials, lighting materials, shapes and heating conditions.
1. Plastic greenhouse
Large-scale multi-span plastic greenhouse is a type of greenhouse that has appeared in the past ten years and has been rapidly developed. Compared with the glass greenhouse, it has the advantages of light weight, less frame material consumption, small shading rate of structural parts, low cost, long service life, etc. Its environmental control ability is basically.
It can reach the same level of glass greenhouses, and the acceptance by users of plastic greenhouses is much higher than that of glass greenhouses in the world, and it has become the mainstream of the development of modern greenhouses.
2. Glass greenhouse
A glass greenhouse is a greenhouse with glass as a transparent covering material. When designing the foundation, in addition to meeting the strength requirements, it should also have sufficient stability and the ability to resist uneven settlement. The foundation connected with the support between the columns should also have sufficient horizontal force transmission and space stability. The bottom of the greenhouse should be located below the frozen soil layer, and the heating greenhouse can consider the influence of heating on the freezing depth of the foundation according to the climate and soil conditions. Have an independent foundation. Reinforced concrete is usually used. Strip foundation. The masonry structure (brick, stone) is usually used, and the construction is also carried out by on-site masonry. A reinforced concrete ring beam is often set on the top of the foundation to install embedded parts and increase the strength of the foundation. Greenhouse, greenhouse project, greenhouse skeleton manufacturer.
Three, solar greenhouse
The front slope is covered with thermal insulation at night, and the east, west, and north sides are single-slope plastic greenhouses with enclosing walls, collectively referred to as solar greenhouses. Its prototype is a single-slope glass greenhouse. The transparent cover material of the front slope is replaced by a plastic film instead of glass, which evolved into an early solar greenhouse. The solar greenhouse is characterized by good heat preservation, low investment, and energy saving, which is very suitable for use in my country’s economically underdeveloped rural areas. On the one hand, solar radiation is an important energy source for maintaining the temperature of the solar greenhouse or maintaining the heat balance; on the other hand, solar radiation is the light source for photosynthesis of crops. The heat preservation of the solar greenhouse is composed of two parts: the heat preservation enclosure structure and the movable heat preservation quilt. The thermal insulation material on the front slope should be made of flexible material so that it can be easily put away after sunrise and put down at sunset. The research and development of new front roof insulation materials mainly focus on the requirements of easy mechanized operation, low price, light weight, aging resistance, waterproof and other indicators.
Four, plastic greenhouse
The plastic greenhouse can make full use of solar energy, has a certain heat preservation effect, and regulates the temperature and humidity in the shed within a certain range by rolling the film.
Plastic greenhouses in the northern regions: mainly play the role of warming cultivation in early spring and late autumn. It can be 30-50 days earlier in spring and 20-25 days later in autumn. Overwintering cultivation is not allowed. In the southern region: In addition to heat preservation of vegetables and flowers in winter and spring, and overwintering cultivation (leaf vegetables), it can also be replaced with a sunshade, which can be used for shading and cooling, rain, wind, and hail prevention in summer and autumn. Plastic greenhouse features: easy to construct, easy to use, less investment, it is a simple protective field cultivation facility. With the development of the plastic industry, it is widely adopted by countries all over the world.
Main device
An indoor greenhouse cultivation device, including a planting trough, a water supply system, a temperature control system, an auxiliary lighting system, and a humidity control system; the planting trough is set at the bottom of the window or made into a screen for planting plants; the water supply system automatically supplies water in a timely and appropriate amount ; The temperature control system includes exhaust fan, hot fan, temperature sensor and constant temperature system control box to adjust the temperature in time; auxiliary lighting system includes plant light and reflector, installed around the planting trough, provides lighting when there is no daylight, so that the plants can progress Photosynthesis, and the refraction of light presents a beautiful landscape; the humidity control system cooperates with the exhaust fan to adjust the humidity and reduce the indoor temperature.
Performance
Greenhouses mainly include three major functions: light transmittance, heat preservation, and durability.
Greenhouse application
Internet of Things Technology (Expanded)
In fact, the Internet of Things technology is the aggregation and integrated application of various perception technologies, modern network technologies, and artificial intelligence and automation technologies. In the greenhouse environment, a single greenhouse can use the Internet of Things technology to become a measurement control area of the wireless sensor network, using different sensor nodes and nodes with simple actuators, such as fans, low-voltage motors, valves and other low-current execution The organization constitutes a wireless network to measure the substrate humidity, composition, pH value, temperature, air humidity, air pressure, light intensity, carbon dioxide concentration, etc., and then through model analysis, automatically regulate the greenhouse environment, control irrigation and fertilization operations, so as to obtain plant growth conditions of.
For agricultural parks with greenhouses, the Internet of Things can also realize automatic information detection and control. By being equipped with wireless sensor nodes, each wireless sensor node can monitor various environmental parameters. By receiving the data sent by the wireless sensor convergence node, storing, displaying and data management, the acquisition, management, analysis and processing of the information of all base test points can be realized, and it can be displayed to the users in each greenhouse in the form of intuitive graphs and curves. At the same time, various sound and light alarm information and SMS alarm information are provided according to the needs of planting plants, so as to realize the intensive and networked remote management of the greenhouse.
In addition, the Internet of Things technology can be applied to different stages of greenhouse production. At the stage when the greenhouse is ready to be put into production, by arranging various sensors in the greenhouse, the internal environmental information of the greenhouse can be analyzed in real time, so as to better select the suitable varieties for planting; in the production stage, the practitioners can use the Internet of Things technology to collect the temperature in the greenhouse Various types of information such as, humidity, etc., to achieve fine management. For example, the opening and closing time of the shading net can be sensor-controlled based on information such as temperature and light in the greenhouse, and the startup time of the heating system can be adjusted based on the collected temperature information, etc.; After the product is harvested, the information collected by the Internet of Things can also be used to analyze the performance and environmental factors of plants at different stages and feed them back to the next round of production, so as to achieve more accurate management and obtain better products.
Working principle
The greenhouse uses transparent covering materials and environmental control equipment to form a local microclimate, and establishes special facilities that are conducive to the growth and development of crops. The role of the greenhouse is to create environmental conditions suitable for crop growth and development to achieve efficient production. Solar radiation dominated by shortwave radiation enters the greenhouse through the transparent materials of the greenhouse. The greenhouse will increase the indoor ground temperature and temperature and convert it into longwave radiation.
Long-wave radiation is blocked by the greenhouse covering material in the greenhouse, thereby forming indoor heat accumulation. The increase in room temperature is called the “greenhouse effect”. The greenhouse uses the “greenhouse effect” to achieve the purpose of crop production, and creates a suitable environment for crop growth during the season when crops are not suitable for open-air planting by adjusting the indoor temperature, thereby increasing crop yields.
Orientation and location issues
It is better to go beyond the frozen layer. The basic design of the greenhouse is based on the geological structure and local climatic conditions. The foundation is relatively deep in cold areas and loose soil areas.
The site selection should be as flat as possible. The site selection of the greenhouse is very important. The groundwater level should not be too high, avoid high mountains and buildings that block light, and for planting and breeding users, sheds cannot be built in polluted places. In addition, areas with strong monsoons should consider the wind resistance of the selected greenhouse. The wind resistance of general greenhouses should be above level 8.
The orientation of the greenhouse has a great influence on the heat storage capacity in the greenhouse, as far as the solar greenhouse is concerned. According to experience, it is better for greenhouses in the south to face westward. This facilitates the greenhouse to accumulate more heat. If multiple greenhouses are built, the spacing between the greenhouses should not be less than the width of one greenhouse.
The orientation of the greenhouse means that the heads of the greenhouse are on the north and south sides respectively. This orientation enables the crops in the greenhouse to be distributed evenly.
The wall material of the greenhouse can be used as long as it has good heat preservation and heat storage capacity. The inner wall of the greenhouse emphasized here must have the function of heat storage, and the masonry of the solar greenhouse must be adapted to local conditions. In order to store heat. At night, this heat will be released to maintain the temperature balance in the shed. Brick walls, cement plaster walls, and soil walls all have heat storage capacity. It is generally better to adopt brick-concrete structure for the walls of greenhouses.
Post time: Apr-07-2021