Supporting Facilities Of Various Greenhouses

Supporting facilities of various greenhouses
Regarding the explanation of various supporting facilities of greenhouses, this article will focus on the supporting facilities other than the main structure of the greenhouse (such as the frame, columns) and covering materials (glass, film), and explain their functions in detail.
The main structure and covering materials of a modern greenhouse or shed are like the human "skeleton" and "skin", while the various supporting facilities are its "muscle system", "circulatory system", "nervous system" and "respiratory system". It is the technical integration of these supporting facilities that transforms a simple wind and rain shelter into an agricultural factory that can precisely control the environment and achieve efficient production.
Chapter 1: Environmental Control System

This is the "central nervous system" of the greenhouse, responsible for creating and maintaining an optimal environment for crop growth.

1. Ventilation System
Function: Regulates greenhouse temperature, humidity, and carbon dioxide concentration, removes harmful gases, and promotes air circulation.
Types and Details:
Natural Ventilation System:
Top-Opening Window System: Utilizes the principle of thermal pressure ventilation (hot air rises). It consists of a rack and pinion drive system or a film roller. A motor drives a drive shaft, which in turn pushes the top window rod to open or close. This is a standard feature of glass and multi-span greenhouses.
Side-Opening Window System: Utilizes the principle of wind pressure ventilation. Also driven by a rack and pinion or a film roller, it opens the side windows.
Forced Ventilation System:
Fan: A large axial fan, typically mounted on the wall at one end of the greenhouse.
Wet Pad: A honeycomb paper device mounted on the opposite wall.
Working Principle: The fan draws air, creating a negative pressure inside the greenhouse. This forces outside air through the water curtain, where the water evaporates and absorbs heat, drawing in cool, moist air. This is the most effective cooling system in summer, and the "fan-water curtain" system must be used in conjunction.

2. Cooling system
Function: Suppresses excessive indoor temperature rise in summer or high-temperature areas.
Types and Details:
Shading and Cooling:
Internal shading system: Installed inside the greenhouse, beneath the frame. It consists of a screen support cable, shade net, rack-and-pinion drive system, and control box. Its functions include reflecting some sunlight for cooling, retaining heat (reducing heat loss at night), and preventing fog droplets (reducing condensation dripping).
External shading system: Installed on the outside of the greenhouse roof, it consists of a high-strength shade net, a rack-and-pinion drive system, and a wind- and rain-resistant frame. Its greatest advantage is that it blocks solar radiation from the outside of the greenhouse, providing a far superior cooling effect than internal shading.
Evaporative cooling: This is the aforementioned "fan-water curtain" system.

Spray cooling: High-pressure spray pipes and nozzles are installed on the roof of the greenhouse to atomize water into extremely fine droplets, which evaporate in the air and absorb heat. This method can both reduce temperature and increase humidity.
3. Heating System

· Function: Provides heat necessary for crop growth during winter or cold weather.
· Types and Details:
Hot water heating: The most common and stable method. It consists of a boiler (heat source: coal, gas, biomass, etc.), hot water pipes (usually installed around the crop roots or between plant rows), and a circulation pump. It provides stable and uniform temperature and long-lasting residual heat.
Hot air heating: Consists of a hot air furnace (which directly heats the air) and air supply ducts (perforated polyethylene film ducts). It heats up quickly and requires less equipment investment, but the temperature stability is not as good as hot water heating.
Radiant heating: such as geothermal cables, laid under the cultivation trough or seedbed, directly heats the roots, with high efficiency
Radiant heating: such as geothermal cables, laid under the cultivation trough or seedbed, directly heats the roots, with high efficiency
LED grow light: The current mainstream technology. It offers low energy consumption, precisely customizable light spectra (such as a red and blue light combination), and low heat generation. It can provide specific light spectra for different crop growth stages.
High-pressure sodium lamps: Traditional grow light: High luminous efficiency, but a fixed light spectrum and high heat generation.
System components: Includes grow light, reflector, voltage stabilizer, and a liftable suspension system (to adjust the light height as needed).

5. Shading System

· Function: Not only used for cooling, but also for photoperiod regulation (e.g., for inducing flowering of short-day crops) and preventing plant burns caused by strong sunlight.
· Detailed Explanation: See the internal and external shading systems mentioned above for the cooling system. Its drive and control system are core supporting facilities.
Chapter 2: Cultivation Support System

This is the crop's "housing" system, which directly determines cultivation patterns and production efficiency.
1. Cultivation Trough and Seedbed System

· Function: Isolates crops from the ground, enabling soilless cultivation, effectively controlling the root environment, reducing soil-borne diseases, and improving worker comfort.
· Types and Details:
· Tidal Seedbed: Consists of a seedbed surface, cultivation containers, supply and return pipes, and a lifting mechanism. During irrigation, the surface rises, allowing the nutrient solution to submerge the crop roots for a period before draining away, saving water and fertilizer.
· Fixed Seedbed/Cultivation Trough: A common soilless cultivation medium used for substrate cultivation. These are typically made of plastic or foam board. They come with a cultivation support, nutrient solution supply pipes, and a return trough.

2. Climbing System

· Function: Supports climbing crops such as tomatoes, cucumbers, and peppers, allowing them to grow upward, fully utilizing the three-dimensional space and improving ventilation and light conditions.
· System Components: Includes growing wire (high-strength plastic wire), a hanging hook, a head wrap (automatic vine wrap), a top support wire mesh, a spool, and a lifter (for periodically lowering vines to extend the growing cycle).
Chapter 3: Water and Fertilizer Management System

This is the greenhouse's "circulatory and digestive system," ensuring precise water and fertilizer supply and recycling.

1. Irrigation System

· Function: Delivers water and nutrients in a timely, quantitative, and precise manner based on crop needs.
· Types and Details:
· Drip Irrigation System: The most common system. Core components include: header system (filter, fertilizer applicator, pressure gauge, control valve), water distribution network (main and branch pipes), and drip irrigation pipes/drip arrows (which deliver water and fertilizer directly to the crop roots).
Sprinkler irrigation systems: Suitable for seedlings or short crops. They consist of sprinkler heads, branch pipes, and a header system.

Mobile sprinklers: Commonly used in large multi-span greenhouses, a single machine can be moved on tracks to irrigate a large area with exceptionally uniform irrigation.
2. Fertilization System

· Function: Linked to the irrigation system, this system injects fertilizer concentrate into the irrigation water according to a preset ratio and formula.
· Types and Details:

· Proportional Fertilizer Pump: Such as piston pumps and diaphragm pumps, this system injects fertilizer proportionally based on water flow.

· Venturi Fertilizer Applicator: This system uses the negative pressure generated by water flowing through the pipe to absorb fertilizer. It has a simple structure and consumes no power, but requires a stable inlet water pressure.
Intelligent integrated fertilization system: This modern, high-tech device integrates an EC/pH monitor, a control unit, a multi-channel fertilizer injection pump, and multiple filters. It monitors the concentration and pH of the nutrient solution in real time and automatically adjusts to preset values, enabling fully automated, precise fertilization.
3. Recovery and Disinfection System

· Function: Collects excess nutrient solution discharged after irrigation, disinfects it, and then recycles it, achieving zero discharge and conserving water and fertilizer resources.
· System Components: Return pipes, sump, and disinfection equipment (e.g., UV sterilizer, high-temperature sterilizer, and ozone generator).
Chapter 4: Automation and Control Systems
This is the "brain" of the greenhouse, integrating all environmental controls and equipment operations.

1. Environmental Control System

· Function: Real-time monitoring and automatic control of greenhouse environmental parameters.
· System Components:
· Sensors: These include temperature sensors, humidity sensors, light intensity sensors, CO₂ concentration sensors, soil moisture sensors, and others, serving as the system's "sensory organs."
Controller: The core processing unit (e.g., a PLC or computer) receives sensor signals and issues commands based on pre-set logic (e.g., an expert system).

Actuator: The device that receives commands from the controller and performs actions, such as motors (opening windows, raising curtains), pumps, solenoid valves, and fans.
2. IoT and Smart Monitoring Platform

· Function: Enables remote monitoring, data recording, analysis, and early warning.
· System Components: Connects the greenhouse controller to the internet via a communication module. Users can access real-time greenhouse data, historical curves, and equipment status anytime, anywhere via a computer or mobile app, and perform remote control. The platform software enables big data analysis to optimize planting strategies.
Chapter 5: Other Auxiliary Facilities

1. Power and Lighting System

· Function: Provides power to all electrical equipment and indoor lighting.
· Details: Includes distribution boxes, indoor lighting (for nighttime operation), cables, and lightning protection devices.
2. Carbon Dioxide Dosing System

· Function: Supplements the CO₂ required for crop photosynthesis within the enclosed greenhouse environment, significantly increasing yields.
· Details: Consists of a CO₂ storage tank or combustion generator, delivery piping, and release nozzles, typically automatically controlled by an environmental control system.

3. Internal Insulation System

Function: Primarily used in tall glass greenhouses, this system adds an internal insulation layer at night, significantly reducing heat loss and achieving significant energy savings.
The supporting facilities of a greenhouse are a concentrated reflection of its technological content and are also the core symbol of the transition from traditional agriculture to modern facility agriculture with controlled environment, efficient production and resource conservation. When investing in a greenhouse project, the main structure is the foundation, but the selection and configuration level of the supporting systems directly determine the actual production performance, operating costs and ultimate economic benefits of the greenhouse. During the design and construction, scientific and reasonable supporting system selection and integration must be carried out according to the crops grown, local climate conditions and investment budget.