In greenhouse planting production, temperature, humidity, air circulation is to determine crop growth, yield and quality of the three core elements, of which air circulation is often the most likely to be ignored by the growers of the key links. Many greenhouse greenhouse crop yellow leaves, rotten roots, powdery mildew, insect pests, low fruiting rate and other problems, the root cause is not fertilization, watering is not appropriate, but poor ventilation caused by the shed micro-environmental imbalance. The traditional manual window opening and ventilation mode relies on manpower, there is a response lag, temperature control is not allowed, day and night regulation is not timely, labor costs and many other disadvantages, it is difficult to adapt to the modernization, large-scale greenhouse planting needs.
Automatic window opener as a low energy consumption, high efficiency, free of manned intelligent ventilation equipment, real-time response to the temperature changes in the shed, automatically complete the whole process of opening, ventilating, closing the window operation, and continue to maintain stable air circulation in the greenhouse, to solve the root causes of poor ventilation caused by the planting of all kinds of problems. This article will explain the core value of greenhouse ventilation, automatic window opener equipment principle, selection techniques, installation process, optimization program and operation and maintenance methods, to help all types of growers to scientifically optimize the greenhouse ventilation system, to create a high quality greenhouse environment suitable for crop growth, and enhance planting revenue.
Many growers unilaterally believe that the core of greenhouse planting is temperature control, watering, fertilizer, ventilation is only an auxiliary link, in fact, good air circulation is the basis for healthy growth of greenhouse crops, directly determining the stability of the micro-environment in the shed. Adequate and uniform airflow (air circulation) can optimize the crop growth environment, to avoid all kinds of planting risks, specific advantages are reflected in the five core dimensions.
Greenhouse is a closed or semi-closed planting space, direct sunlight during the day, the temperature inside the shed will quickly soar, especially in the spring and summer seasons, the temperature inside the shed at noon can exceed 40 ℃ in half an hour, far more than most of the vegetables, flowers, nursery crops suitable for the growth of temperature. Long-term high-temperature environment will lead to excessive transpiration, leaf wilting, water loss, flower bud differentiation is blocked, fruit scorching, and in severe cases, the whole plant directly withered. Good ventilation system can quickly replace the high temperature in the shed turbid air, balance the temperature difference between day and night in the shed, regional temperature difference, to avoid local temperature is too high, to create a constant temperature for the crop, stable growth temperature environment, effectively avoid high temperature stress brought about by planting losses.
Greenhouse watering, soil evaporation, crop transpiration will continue to produce water vapor, water vapor can not be discharged in a timely manner under the closed environment, which will lead to high humidity in the shed, leaves, film, stents frequently appear on the surface of the condensation of water. High humidity is a breeding ground for fungi and bacteria, and is also the core cause of various diseases. High-quality ventilation and circulation system can timely discharge excess water vapor in the shed, accelerate the evaporation of water on the leaf surface, avoid water condensation, and steadily control the humidity in the shed in the appropriate zone for the crop, thus reducing the planting risk of high humidity from the source.
The air stagnation, high humidity and stuffy environment in the shed is the high incidence of fungal diseases such as powdery mildew, downy mildew, gray mold, root rot, and insect pests such as aphids, red spiders and whiteflies. Inadequate ventilation will allow germs and eggs to remain in the shed for a long time, spreading rapidly, once the outbreak of disease, will not only cause crop yield reduction, but also require frequent spraying of pesticides, increasing the cost of planting and the risk of pesticide residues in agricultural products. Continuous and stable air circulation can destroy the hot and humid environment suitable for the survival of pests and diseases, inhibit the propagation of germs and insect pests, significantly reduce the incidence of pests and diseases, and realize green and lightweight planting management.
The natural soft air flow, equivalent to providing crops with “artificial breeze”, can stimulate the growth of crop stalk lignification, avoiding crop growth, weak collapse, so that the stalk is more robust and tough. At the same time, the air circulation can make the crop leaves uniformly wind and light, avoiding the dense branches and leaves to smother the growth of futile, and effectively improve the overall crop resistance to collapse and disease resistance, so that the plant growth is more robust, laying the foundation for the late high-yield and stable yield.
Crop photosynthesis requires sufficient carbon dioxide, closed greenhouse after a night of closure, the concentration of carbon dioxide in the shed greatly reduced, oxygen accumulation, will seriously affect the efficiency of photosynthesis during the day. Good ventilation can replace the air in the greenhouse in a timely manner, replenish fresh carbon dioxide, and evenly distribute the gases in the greenhouse, so that each crop can photosynthesize efficiently. At the same time, moderate air flow can assist the pollination of flowers, fruits and vegetables crops, reduce the problem of flower and fruit drop, and significantly improve the fruiting rate and yield.
Growers can through the shed environment and crop status, quickly determine whether the ventilation system is up to standard: crop leaves frequent dew, long-term wet and not dry; shed membrane walls continue to hang full of water droplets, dripping serious; plant growth, stalks weak, dense smothering of branches and leaves; shed frequent outbreaks of fungal diseases, insect pests repeatedly; too large a temperature difference between day and night, high temperature in the shed in the afternoon hot and stuffy; low fruiting rate of the crop, fruit deformities, uneven growth potential. Any one of the above situations, are indicative of insufficient greenhouse ventilation, the need to immediately optimize the ventilation program.
There are many shortcomings in the traditional manual window opening and ventilation: manual guarding is time-consuming and laborious, and it is impossible to realize all-weather real-time control; the temperature difference between morning and evening, unexpected weather can not respond in time, and it is easy to appear high temperature stuffy greenhouse, cold at night; the size of the window opening is all based on experience, and the ventilation volume is unstable, and it is difficult to accurately control the environment in the greenhouse. The automatic window opener is an intelligent passive ventilation equipment customized for greenhouses, without human intervention, according to the temperature of the greenhouse can automatically start and stop, adjust the window opening amplitude, perfectly adapted to all types of greenhouse ventilation needs, is the optimal solution to replace artificial ventilation.
The core control logic of mainstream automatic window opener on the market is divided into four categories, respectively adapted to different planting scenarios, the core of which is “temperature sensing, automatic adjustment”, without artificial real-time control, and can realize 24-hour unattended ventilation. Among them, the temperature control hydraulic, wax column thermal type is passive drive, without electricity; solar energy, intelligent electric models for active drive, suitable for high-precision control needs. According to the temperature rise and fall in the shed, the equipment can automatically extend and retract the actuator, control the opening and closing angle of the skylight and side windows, automatically open the windows to ventilate and cool down when the temperature rises, and automatically close the windows to keep warm when the temperature falls, so as to accurately maintain a stable temperature in the shed.
(1) Wax column thermal window opener (thermal type): this is the most commonly used basic equipment for family greenhouses and small and medium-sized greenhouses, the core of which relies on the principle of thermal expansion and contraction of the thermal wax column. When the temperature rises, the wax column is heated and expands to push the pusher to open the window; when the temperature falls, the wax column contracts and closes the window by spring reset. This type does not need electricity, no wiring, simple installation, cost-effective, low failure rate, free of routine maintenance, suitable for ordinary fruit and vegetable, flower planting greenhouses. The disadvantage is that the precision of temperature control is relatively basic, unable to realize the refinement of the angle adjustment, only suitable for conventional planting scenarios.
(2) Solar automatic window opener: it is an energy-saving upgraded equipment, equipped with solar charging panel and energy storage battery, absorbing solar energy during the day to provide electricity for the equipment operation, zero electricity cost, energy saving and environmental protection. Compared with the wax column model, the temperature control response is more sensitive and the window opening amplitude adjustment is more accurate, which can be adapted to small and medium-sized greenhouses and field greenhouses far away from the utility. The whole process of autonomous power supply is not affected by power failure, suitable for outdoor planting sites without power supply conditions, taking into account the practicality and energy saving.
(3) Electric Intelligent Window Opening System: It belongs to high-end refinement equipment, equipped with temperature and humidity sensors and intelligent controllers, which can customize the temperature control zone, ventilation duration, opening and closing angle, and support remote control by cell phone, timer start/stop, and linkage ventilation. It is suitable for large-scale continuous greenhouse, seedling greenhouse, high-end flower greenhouse and scientific research planting base. Advantage is that the regulation and control precision is very high, comprehensive functions, can be linked to the fan, sunshade, sprinkler system to realize the integration of intelligent control; disadvantage is that the cost is higher, the need for wiring and installation, dependent on the power supply.
Selection of automatic window opener can not only look at the price, the four core parameters directly determine the use of the effect and service life. The first is the temperature control range, conventional planting adaptable 0-40 ℃ adjustable range, can meet the needs of four-season planting; the second is to enhance the load-bearing, according to the size of the window, the weight of the corresponding load-bearing specifications, to avoid the lack of thrust leads to open the window is not in place; the third is the material durability, preferably aluminum alloy, stainless steel corrosion-resistant materials, resisting the high humidity, acid and alkali corrosion in the shed; the fourth is the weather resistance, need to be adapted to high temperatures, low temperatures, wind and rain, outdoor long-term use without aging, no aging, no corrosion, outdoor long-term use. Outdoor long-term use without aging, not jammed.
Different greenhouse structure, size, regional climate, planting category, corresponding to the window opener selection program is completely different. Blind purchase of equipment is prone to insufficient ventilation, window opening stuttering, waste of equipment and other problems, combined with the site conditions of scientific selection, in order to maximize the ventilation effect.
Rigid glass/PC board greenhouse: this kind of greenhouse has strong sealing and good heat preservation, but the ventilation resistance is big, it is suitable to use the electric model with stronger load bearing and stable thrust or high matching wax post window opener, and it is preferred to adapt to the roof skylight, to ensure that the amplitude of the window is sufficient, and to replace the air in the shed quickly. Arch-shaped film greenhouse: light weight windows, low resistance to opening and closing, conventional wax post thermal and solar window opener can meet the demand, the most cost-effective, suitable for large-scale popularization and installation. Continuous large greenhouse: large space volume, high difficulty in air circulation, need to be matched with multiple intelligent electric window openers to achieve synchronized ventilation in zones, to avoid uneven temperature and humidity differences in the shed.
Roof skylight is the core ventilator of greenhouse, using the “chimney effect” to quickly discharge the top layer of high temperature and turbid air, it is recommended to use large thrust window opener to ensure complete opening and closing; side window ventilation mainly focuses on horizontal air convection, suitable for conventional small and medium-sized window opener, can be paired with the skylight to form a cross-ventilation; rolled film vents are suitable for special electric rolled film window opener, which is suitable for the overall ventilation needs of thin film greenhouses. It is suitable for the overall ventilation needs of film greenhouses.
High temperature and high humidity areas: high temperature and high humidity in summer, high humidity in the rainy season, need to use sensitive temperature control, open and close a wide range of equipment, preferably with intelligent models, which can increase the frequency of ventilation, rapid humidity and cooling, to avoid the problem of high incidence of disease.
Areas with big temperature difference between day and night: the temperature difference between day and night is huge, low temperature at night, we need to choose the equipment with precise temperature control and sensitive reset, open the window in time during the day to dissipate the heat, and close the window accurately at night to keep warm to avoid heat loss and freezing of seedlings at low temperature. Windy and rainy areas: Priority should be given to waterproof, windproof and anticorrosive reinforced window opener to avoid equipment jamming and water damage in windy and rainy weather.
No utility power, the pursuit of low-cost maintenance-free retail planting, prefer wax column thermal window opener, one-time investment, zero cost, to meet the basic ventilation needs; simple power supply, the pursuit of energy-efficient large-scale planting, the choice of solar window opener, taking into account the accuracy and energy-saving; large-scale bases, high-end planting, the pursuit of fully automated intelligent management, the choice of electric intelligent window opener system, support for remote control, precise regulation, adapt to the refinement of planting, the choice of electric intelligent window opener system, support for remote control, precise regulation, adapt to the refinement of planting. The system supports remote control and precise regulation, and is suitable for fine planting mode.
Standardized installation steps and safety norms for automatic window opener
High-quality equipment requires standardized installation process, installation is not in place, there will be window jamming, window closure, uneven force, equipment damage and other problems, directly affecting the ventilation effect. The following is a standardized step-by-step installation process, which is suitable for most greenhouse skylight and side window installation scenarios.
Prepare supporting screws, expansion bolts, wrenches, level, tape measure, screwdriver, waterproof tape; check the integrity of the window opener accessories, including actuators, fixed brackets, springs, temperature control components, waterproofing accessories, etc., to ensure that there is no damage, no missing.
Clean up the dust, rust and debris on the window frame and bracket installation position to ensure that the installation plane is flat and firm; check whether the window opening and closing is smooth, clean up the jammed obstacles and repair the deformed window frame to avoid overloading the equipment due to window failure; do waterproof and rustproof pretreatment for the outdoor installation position to prolong the service life of the equipment.
Adopt level meter to calibrate the installation position to ensure horizontal installation of the window opener to avoid uneven tilting force; fix the base bracket, lock all the fixing bolts to ensure that the bracket and the greenhouse structure are closely adhered to without loosening; connect the connecting point of the actuator and the window frame, and adjust the length of the actuator to ensure that the window opener and the window closure stroke is smooth without any jamming and dead; focus on the reinforcement of the bearing key point in the skylight installation, and ensure the opening and closing angle of the side window installation is even and suitable for the ventilation demand. Adapt to the ventilation needs.
After the installation is completed, manual trial run, test the window opening and closing the whole process is smooth, reset in place; according to the appropriate temperature of planting crops, adjust the temperature control start interval, conventional fruit and vegetable crops set 25-28 ℃ window, 20-22 ℃ window; intelligent models of equipment can be set to open and close the angle of the ventilation, ventilation time, timing procedures, adapted to meet the needs of fine ventilation; calibration is completed and repeated tests 3-5 times, to ensure responsive, stable operation. Ensure sensitive response and stable operation.
Installation of the entire power-off operation, electric models of equipment to do a good job of line waterproof protection; prohibit overloaded installation, according to the weight of the window to match the corresponding thrust equipment; avoid installation of tilt, screws loose, to prevent the equipment from falling off, deformation of the window frame; high temperature hours prohibit the direct debugging of the device, to avoid the temperature control component error; do not push and pull the actuator by force, to prevent damage to the internal structure, affecting the accuracy of the temperature control. Common installation misunderstandings include installation tilt leading to jamming, poor fixation triggering equipment shaking, unreasonable temperature control settings leading to smothering or heat loss, improper stroke adjustment leading to poor window closure leakage and leakage of air and water.
The ventilation effect of a single window opener is limited, and if you want to realize a full range of greenhouse air circulation without dead ends, you need to create a systematic ventilation system through scientific layout, equipment matching and airflow design to completely solve the problem of local ventilation dead ends.
Adopt “roof skylight + side ventilation window” combination layout, the top window opener is responsible for exhausting high temperature and cloudy air, moisture, exhaust gas in the shed, using the chimney effect of rising hot air to rapidly cool down the temperature and humidity; the side window opener to introduce fresh cold air from the outside, the formation of upper and lower air convection, to completely eliminate the dead ends of ventilation in the shed. Large greenhouses can use multi-point distributed installation, uniform arrangement of window openers to ensure that the temperature, humidity, air circulation everywhere in the shed is uniform.
As the core equipment of passive ventilation, the automatic window opener can be combined with a variety of auxiliary equipment to build an all-round ventilation system. With exhaust fan and air intake fan, to realize active forced ventilation, extreme high temperature, high humidity weather quickly replace the air in the shed; with shutters, film vents, expanding the ventilation area, matching the ventilation needs of large-space greenhouse; with the circulation fan, to promote the lateral circulation of air in the shed, to solve the problem of dense branches and leaves, the corner of the shed is not ventilated properly, so that the air circulation is more uniform.
Reasonable control of the opposite side window and skylight opening and closing status, the formation of stable cross convection airflow, accelerate air replacement; the use of hot air rising principle, through the top skylight focused on the discharge of hot air, the bottom of the side window to make up for the new air, build a high-efficiency chimney effect, significantly improve the ventilation efficiency, without the need for high-power equipment can be realized rapid air exchange, energy-saving and efficient.
High-end planting scenarios can link the automatic window opener with temperature and humidity sensors, intelligent controllers, and meteorological monitoring equipment to realize fully automatic intelligent regulation and control. The system can automatically adjust the window opening angle and ventilation duration according to the real-time shed temperature, humidity, outdoor wind, and light data, and start and stop the ventilation quickly when the weather changes suddenly, completely getting rid of manual intervention and realizing the optimal all-weather ventilation status.
The automatic window opener has a simple structure and low failure rate, but it has been in a high humidity, high temperature and open environment for a long time. Regular maintenance can greatly prolong the service life of the equipment, ensure the stability of the regulation precision, and avoid faulty shutdowns affecting the planting and ventilation.
Monthly clean up the equipment surface dust, cobwebs, debris, clean up the push rod, bracket activity parts of the blockage, to ensure smooth operation; quarterly for the activities of the joints, telescopic push rod coated with special lubricating grease, to prevent rust jamming; regular inspection of the fixed bolts, connecting the points, timely fastening of loose fittings, to avoid the equipment shaking and shifting; intelligent models, solar models regularly clean up the photovoltaic panel dust, check the aging of the line, waterproof condition The smart models and solar models regularly clean the dust of PV panels and check the aging and waterproof condition of the lines to ensure stable power supply.
In the summer high temperature season, focus on checking the temperature control sensitivity of the equipment to avoid high temperature failure, and do a good job of sun protection and anticorrosion protection; rainy season to strengthen the waterproof inspection, to prevent rainwater from seeping into the internal equipment leading to failures; in the fall and winter cooling season, timely fine-tuning of the temperature control parameters, to match the low-temperature environment, to avoid over-ventilation at night leading to excessive cooling in the shed; idle time in the winter, clean up the stains on the equipment, and do a good job of anti-rust insulation, which can be dismantled to avoid low-temperature freezing, damage, accumulation of water, and so on. To avoid low-temperature freezing and snow damage to the equipment, we should clean up the equipment during the idle time in winter and make it rust-proof and heat preservation.
Failure 1: window jamming, open and close not smooth: mostly debris clogging, rusty fittings, installation tilt caused by cleaning up the clogging, lubrication of moving parts, calibration of the installation level can be solved. Failure 2: insufficient thrust, open the window is not in place: the probability is that the load bearing mismatch, spring aging, insufficient lubrication, replacement of suitable load-bearing equipment, replacement of aging springs, comprehensive lubrication can be repaired. Failure three: temperature control failure, open and close untimely: wax column models are mostly thermal components aging, intelligent models are mostly sensor offset, line failure, recalibrate the parameters or replace the core components. Failure four: close the window is not strict, leakage of wind and water: improper adjustment of the push rod stroke, window frame deformation, bracket loosening, fine-tuning the stroke, tighten the bracket, repair the window frame can be solved.
Avoid long-term overloaded operation of the equipment, in strict accordance with the load-bearing specifications adapted to the window; prohibit external forces to force push and pull, impact equipment, to protect the internal precision temperature control structure; high humidity, acid and alkali shed environment on a regular basis to do anticorrosion maintenance; extreme rainstorms, gusty weather in advance to check the tightening of equipment, to avoid damage to the external forces. Under standardized maintenance, the service life of conventional window opener can reach 5-8 years, and the intelligent model equipment can be used stably for more than 8 years.
Greenhouse ventilation needs to be dynamically adjusted in combination with the climate characteristics of the four seasons, with monitoring equipment and auxiliary cooling and moisturizing means, with automatic window openers to achieve fine ventilation management, to adapt to the planting needs of different seasons.
With temperature and humidity recorder, intelligent monitoring terminal, real-time view of the environmental data in the shed, according to the data to fine-tune the temperature control parameters of the window opener, say goodbye to empirical management, so that the ventilation regulation and control is more accurate, and timely avoidance of high temperature, high humidity, low temperature risk.
In summer, strong light and high temperature, simple ventilation can not quickly cool down the temperature, can be used with sunshade to block the strong light, combined with micro-spray cooling, wet curtain ventilation system, and automatic window opener linkage, quickly reduce the temperature in the shed to avoid crop heat stress, and at the same time to ensure that the air circulation, balanced temperature and humidity.
Spring: large temperature difference between day and night, fine-tuning the window start temperature, moderate ventilation during the day, close the window at night in time to keep warm, to prevent freezing inversion; summer: increase the ventilation volume, prolong the ventilation time, the use of upper and lower convection ventilation, rapid cooling and humidity, to prevent the outbreak of pests and diseases; fall: dry and rainy, moderate ventilation, to avoid over-ventilation leading to low humidity in the shed, affecting the growth of the crop; winter: strict control of ventilation time, select the midday high-temperature time short-time ventilation, to avoid crop heat stress, while ensuring balanced temperature and humidity. In winter: strictly control the ventilation time, choose the midday high-temperature time to ventilate for a short period of time, and keep the rest of the time closed for heat preservation, taking into account the needs of air exchange and heat preservation.
Priority is given to the use of solar energy, thermal passive automatic window opener, the whole process of zero electricity, low energy consumption, reduce the operating costs of planting; reasonable planning of ventilation time, to avoid ineffective ventilation led to heat, humidity loss; through precise ventilation to reduce the occurrence of pests and diseases, reduce the consumption of pesticides, water and electricity, to realize the modernization of green energy-saving, high-efficiency and stable production of the planting model.
Greenhouse ventilation is the core foundation of healthy crop growth, high yield and high quality, poor ventilation brought about by high temperature stress, high humidity diseases, growing and collapsing, reduced yield and poor quality and other problems, is a key factor restricting the planting yield. The traditional artificial ventilation mode of low efficiency, large error, high cost, has long been unable to adapt to the needs of modern planting. With the core advantages of all-weather response, precise temperature control, no artificial guard, low energy consumption and high stability, the automatic window opener has completely solved the greenhouse ventilation control problems.
Through scientific selection, standardized installation, systematic ventilation layout, normalized operation and maintenance, automatic window opener can continuously optimize the air circulation environment in the shed, accurately regulate the temperature, humidity, gas concentration, reduce the incidence of pests and diseases from the root, strengthen the crop growth, and significantly improve the crop yield and quality. At the same time, it significantly reduces the cost of manual labor, pesticides and water and electricity losses, realizing cost reduction and efficiency for growers.
For large-scale greenhouses, family planting greenhouses, nursery bases, upgrading the automatic window ventilation system is not a redundant investment in equipment, but the most cost-effective and stable return on planting upgrade program. Optimizing the greenhouse ventilation environment and using the automatic window opener can make the greenhouse planting management easier and smarter, and achieve the planting goal of stable production throughout the year, improving quality and increasing income.
