Main parameters controlled in automated greenhouses

86 
software and hardware complex for reliable measurement of the climate in the 
greenhouse. [6].
Automated control system adjusts the following operating parameters: 
– ventilation systems; 
– air recirculation systems; 
– curtain systems; 
– drip irrigation systems; 
– CO
2
feeding systems for plants; 
– artificial lighting systems for seedlings; 
– greenhouse heating system. 
Air vents open and close using a system with a rail mechanism. The 
mechanism for opening the vents is a system of shafts and gear racks, which, when 
interacting with each other, actuate the pushing element that lifts the vents. The rods 
are driven by gear motors. The gear motors are equipped with emergency switches 
and adjustable limit switches (Fig. 1.5). 
Figure 1.5 – Ventilation of the greenhouse with a vent system 
The greenhouse ventilation system includes: 
– cylinder; 
– cylinder holder; 
– cylinder rod; 
– coupling; 
– hairpin; 
– locking pin; 

87 
– lever (A); 
– lever (B); 
– frame mount; 
– window mount; 
– clamp. 
For artificial mixing of air in the greenhouse complex in order to evenly 
distribute temperature fields, an air recirculation system is used to reduce overheating 
of plants and eliminate areas with high humidity. Air recirculation is carried out by 
axial fans. The fans work in an automated mode. Figure 1.6 shows an image of an 
axial fan [9]. 
Figure 1.6 – Recirculation fan 
Fans provide air recirculation, controlled by the temperature difference at the 
control points controlled by temperature sensors.
In this case, the control system performs the following functions: 
– regulation of temperature and humidity of the supplied air;
– the regulating effect is transmitted to the heat and coolant valves, valves for mixing 
the outside air through signals arriving at the electric drives;
– regulation of excess pressure inside the greenhouse by changing the position of the 
windows;
– air distribution control by turning on/off and modifying the fan speed. 
The main and important factor in controlling the growth, development and 
fruiting of plants is the temperature regime. Temperature affects photosynthesis, 
respiration, movement of substances, growth and fruiting. 

88 
The optimal temperature regime for photosynthesis in vegetables is from 
20°C to 24°C. Extremely high temperatures negatively affect the processes of 
growth, development and pollination. 
The curtain screen system for thermal protection and light reflection is 
designed for maximum energy saving in the cold period and at night, as well as for 
shading in greenhouse complexes with active solar radiation in the spring-summer 
season (Fig. 1.7) [6]. 
Figure 1.7 – Curtain screens 
Due to the flexibility of the material, the screens fold and do not obscure the 
plants. The use of screens is also necessary to prevent condensation. The shutter 
mechanism is performed separately for each climatic zone of the greenhouse block. 
The system of curtain screens opens and closes as necessary in the automatic mode 
by the ACS signal by a microclimate or remotely [8]. 
Drop watering of plants ensures the supply of water directly to the rhizome - 
in small batches and individually to each bush, which is achieved by installing an 
extensive system of rubber or plastic tubes with droppers. With this approach, the 
topsoil will always be moist, and the root will receive water in the amount that it 
needs. There are solutions regarding cold water - its slow supply ensures the required 
heating. For watering, it is enough just to open the tap - a smart system eliminates the 
tedious "runs" with a watering can or hose or bucket (Fig. 1.8) [8]. 

89 
Figure 1.8 – Compensated drip lines 
The description of how watering works without human intervention: 
– remote Control; 
– weather sensor; 
– control wires; 
– sprinkler; 
– drip irrigation system; 
– drip irrigation connection kit; 
– solenoid valve; 
– water outlet; 
– flexible supply system; 
– mesh filter; 
– purge system unit; 
– compression fittings. 
For growing vegetables, a drip irrigation system, a water supply and drainage 
collection system are mounted separately for each greenhouse. 
The water supply is provided in collapsible metal containers [8]. Water for 
drip irrigation passes through a filtration system that purifies water from suspended 
solids present in it from 70-100 microns in size. Silica sand is used as a filler. 
The dissolution of fertilizers is carried out in tanks in accordance with the 
chemical compatibility of fertilizers. The nutrient solution is cleaned using a disc 
filter. 

90 
Trunk polyethylene pipes are used to supply the solution to valve groups and 
from valve groups to irrigation lashes [6]. In the valve groups, to ensure automatic 
control of irrigation, solenoid valves are mounted. 
The system for supplying, distributing and regulating the concentration of 
CO
2
in the volume of greenhouses is designed to produce carbon dioxide and the 
distribution of CO
2
in the greenhouse and is carried out using condensers at the exit 
of the flue gases from boilers and distribution pipelines in sections of the 
greenhouses. Monitoring of CO
2
in the air of greenhouses is carried out 
automatically. 
In the enclosed space of the greenhouse, especially in winter, when 
ventilation is practically absent, the CO
2
level can significantly decrease to 150 ml/m
3
during the day, and at night it will increase 450-500 ml/m
3
(usually the CO
2
concentration is 300 ml/m
3
for normal plant life for photosynthesis). 
Figure 1.9 – CO2 system 
Gases enter the plants through polymer sleeves that extend from the 
distribution gas pipeline inside the greenhouse. Each compartment has 1 drainage pit 
with a submerged pump for collecting and draining condensate into a storm sewer. 
The set of equipment for the CO
2
dosing system also includes a CO
2
sensor and a set 
of toxic gas sensors, a fully functional control system (climate computer). 
When programming a climate computer (to open transom), it should be noted 
that with systematic top dressing, a higher temperature in the greenhouse is 
permissible. To ensure a uniform concentration of CO
2
in the air (over the area of the 
greenhouse) and to improve the gas exchange of plants in high greenhouses, a group 

91 
of special circulation fans are used that create uniform circular air movement inside 
the structure at a low speed of up to 1 m/s [8]. 
The evaporative cooling and humidification system is designed to artificially 
lower the temperature of the air in the greenhouse below the temperature of the 
outside air due to adiabatic heat absorption during the evaporation of finely dispersed 
moisture supplied to the volume of the greenhouse. 
Evaporative cooling system is provided sectional. Each section is serviced by 
one solenoid valve. The inclusion of valves is automatic according to the indicators 
of humidity and temperature sensors. The estimated inclusion interval is determined 
by the agronomist technologist depending on the crops grown and the type of 
equipment. The valves are switched on alternately. 
Modern technologies for growing vegetable crops require constant 
maintenance of the given microclimate regimes in the greenhouse complex. ACS 
with a microclimate allows you to save 15-25% of heat with an increase in the yield 
of vegetable crops, improve the working conditions of personnel and increase the 
general culture of production. The use of a computerized system provides high 
accuracy of supporting the required microclimate parameters, taking into account 
changes in external meteorological conditions and agrotechnical problems, by 
influencing the executive mechanisms and equipment of the following technological 
systems and processes: 
– collection of external meteorological parameters; 
– control of the heating system of greenhouses; 
– ventilation control; 
– control of recirculation fans; 
– management of carbon dioxide dosing systems, maintaining the level of 
carbon dioxide concentration in the volume of greenhouses; 
– control and management of the assimilation lighting system; 
– control of horizontal curtain screens. 

92 
All information about the technological processes is displayed on a computer 
monitor with the creation of archive databases presented in a form convenient for 
analysis [12], [13]. 
Figure 1.10 – Central Control Computer 
Control and management of all technological processes in greenhouses is 
carried out "online". 
The use of ACS microclimate in the greenhouse complex (Fig.1.11) provides: 
– increased yield of vegetable crops; 
– reduction in energy consumption; 
– improved reliability and efficiency of equipment; 
– reliable and timely technological information; 
– prompt response to signals about emergency and pre-emergency situations 
[14]. 

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