Greenhouse carbon dioxide precise increasing system and method based on canopy photosynthetic demand

Abstract

The application provides a greenhouse carbon dioxide precise supply system and method based on canopy photosynthesis demand, which comprises a combustion machine unit, a heat exchange and cooling unit, a gas distribution unit, a control unit, a flue gas deep purification module and at least one photosynthetically active radiation sensor; wherein the flue gas deep purification module is connected between the heat exchange and cooling unit and the gas distribution unit, and is used for removing harmful substances in the combustion flue gas; the photosynthetically active radiation sensor is used for monitoring the light intensity of the crop canopy; and the control unit dynamically activates or disables the feedback control loop based on the CO2 concentration according to the comparison result of the light intensity and the preset threshold value, so as to control the running state of the combustion machine unit and the CO2 output of the gas distribution unit. The application avoids invalid supply under weak light conditions, improves the CO2 utilization efficiency, effectively removes harmful substances in the combustion flue gas, and guarantees the physiological safety of crops.

Description

Technical Field

[0001] This invention relates to the field of smart agriculture technology, and in particular to a greenhouse carbon dioxide precision application system and method based on canopy photosynthetic requirements. Background Technology

[0002] Carbon dioxide (CO2) is the primary substrate for plant photosynthesis. In the relatively enclosed environment of a greenhouse, when sunlight is abundant during the day, crop photosynthesis is vigorous, often resulting in indoor CO2 concentrations significantly lower than those in the outside atmosphere. This becomes a key environmental factor limiting crop yield and quality. Therefore, CO2 enhancement in greenhouses (commonly known as "gas fertilization") has become a common method for increasing yields in protected horticulture. Currently, CO2 enhancement technologies applied in greenhouses mainly fall into the following categories: First, using liquefied CO2 cylinders or liquid CO2 storage tanks to release CO2 into the greenhouse through pressure reducing valves and pipelines; second, using fuels such as natural gas, propane, and kerosene to burn in burners and collecting the CO2-rich flue gas for application in the greenhouse; and third, applying solid CO2 particles or generating CO2 through chemical reactions. Among these, combustion methods have gained attention in some large-scale greenhouses due to their relatively low gas source cost and high equipment integration. However, the aforementioned existing technologies all have significant limitations in practical applications, making it difficult to achieve precise, safe, and efficient CO2 supply. Most existing CO2 enhancement systems rely on fixed-time programs or single CO2 concentration thresholds for on / off control, failing to achieve real-time linkage with light intensity. When light is insufficient, crop photosynthesis is limited by light energy, and CO2 enhancement cannot effectively promote photosynthesis, instead resulting in a serious waste of gas resources. Conversely, when light is sufficient, if CO2 supply fails to respond promptly, the full potential of light energy cannot be realized. When CO2 is generated through combustion, the flue gas after fuel combustion may contain harmful substances in addition to CO2, such as carbon monoxide (CO), nitrogen oxides (NOx), and unburned hydrocarbons (VOCs). Existing combustion-type CO2 enhancement devices are typically equipped with only simple heat dissipation or cooling structures, lacking deep purification treatment for these harmful components. Directly applying such flue gas to the crop canopy may lead to long-term accumulation of leaf damage, physiological metabolic disorders, and even food safety risks. Significant differences in light intensity often exist between different areas within a greenhouse. This stems from various factors, including variations in greenhouse structure (such as columns, beams, and wall shading), orientation (such as north-south orientation), weather changes, and mutual shading between adjacent crops. However, existing CO2 enhancement systems cannot provide differentiated CO2 supply control for different light-affected areas. This results in insufficient CO2 supply in high-yield areas with ample sunlight, while in low-yield areas with limited sunlight continue to receive CO2, further exacerbating resource waste and uneven output. Summary of the Invention

[0003] This invention provides a greenhouse carbon dioxide precision application system and method based on canopy photosynthetic requirements, which solves the defects of existing CO2 application technologies, such as the disconnect between control logic and light intensity, lack of deep purification of combustion flue gas, and insufficient spatial control capabilities.

[0004] This invention provides a greenhouse CO2 precision application system based on canopy photosynthetic requirements, comprising: Combustion unit, heat exchange and cooling unit, gas distribution unit, control unit, flue gas deep purification module, and at least one photosynthetically active radiation sensor; in, The flue gas deep purification module is connected between the heat exchange and cooling unit and the gas distribution unit, and is used to remove harmful substances from the combustion flue gas. The photosynthetically active radiation sensor is used to monitor the light intensity of the crop canopy. The control unit is electrically connected to the photosynthetically active radiation sensor, the combustion engine unit, and the gas distribution unit, respectively, and is used to dynamically activate or disable the feedback control loop based on CO2 concentration according to the comparison result of the light intensity and the preset threshold, so as to control the operating status of the combustion engine unit and the CO2 output of the gas distribution unit.

[0005] According to the greenhouse CO2 precision application system based on canopy photosynthetic demand provided by the present invention, the flue gas deep purification module includes at least a primary catalytic oxidizer and a primary selective adsorption filter. The catalytic oxidizer is used to convert carbon monoxide and incompletely burned hydrocarbons in flue gas into carbon dioxide and water. The selective adsorption filter is used to adsorb and remove nitrogen oxides.

[0006] According to the greenhouse CO2 precision application system based on canopy photosynthetic demand provided by the present invention, the gas distribution unit is divided into multiple independently controllable zones, each zone is equipped with an independent control valve and a corresponding photosynthetically active radiation sensor. The control unit is also used to perform differentiated CO2 supply control for each zone based on the light intensity in different areas of the greenhouse.

[0007] According to the greenhouse CO2 precision application system based on canopy photosynthetic requirements provided by the present invention, the gas distribution unit includes a main air duct and a plurality of sub-air ducts branching off from the main air duct. Each zone corresponds to at least one sub-air duct, and the outlet of the sub-air duct extends into the interior of the crop canopy or is placed on the outside of the cotyledons.

[0008] According to the greenhouse CO2 precision application system based on canopy photosynthetic demand provided by the present invention, the control unit is further configured to perform differentiated CO2 supply control for each zone according to the light intensity of different areas within the greenhouse, including: When the light intensity is lower than the preset threshold, the CO2 application to the corresponding zone is paused; When the light intensity is higher than the preset threshold and the CO2 concentration is lower than the preset target value, the CO2 increase in the corresponding zone is activated.

[0009] The greenhouse CO2 precision application system based on canopy photosynthetic demand provided by the present invention also includes a carbon monoxide alarm, which is connected to the control unit; The carbon monoxide alarm is used to detect carbon monoxide concentration; The control unit is also used to automatically cut off the operation of the burner unit and issue an alarm signal when the carbon monoxide concentration detected by the carbon monoxide alarm exceeds a preset safety threshold.

[0010] According to the greenhouse CO2 precision application system based on canopy photosynthetic requirements provided by the present invention, the heat exchange and cooling unit includes a blower and a heat exchanger, which are used to cool the high-temperature flue gas generated by combustion to low-temperature CO2 gas with a temperature difference between the flue gas and the greenhouse interior environment within a preset range.

[0011] This invention also provides a method for precise CO2 application in greenhouses based on canopy photosynthetic requirements, comprising: Real-time monitoring of photosynthetically active radiation intensity and CO2 concentration in crop canopy; Determine whether the photosynthetically active radiation intensity is higher than a preset threshold; When the photosynthetically active radiation intensity is higher than the preset threshold, the monitored CO2 concentration is compared with the preset target concentration, and the operating status of the burner unit and the CO2 output of the gas distribution unit are controlled according to the comparison result.

[0012] According to the greenhouse CO2 precision application method based on canopy photosynthetic demand provided by the present invention, zonal calibration is performed before monitoring is initiated; The CO2 concentration and light intensity are monitored in real time by environmental sensors in each zone and fed back to the control unit to adjust the operating status of the combustion unit corresponding to each zone and the CO2 output of the gas distribution unit.

[0013] The greenhouse CO2 precision application method based on canopy photosynthetic demand provided by the present invention further includes, before controlling the CO2 output of the gas distribution unit: The flue gas generated from combustion is subjected to cooling and deep purification treatment in sequence. The deep purification treatment includes a catalytic oxidation step and a selective adsorption step to remove carbon monoxide, nitrogen oxides and incompletely burned hydrocarbons from the flue gas.

[0014] This invention provides a greenhouse carbon dioxide precision application system and method based on canopy photosynthetic demand. The system includes a combustion engine unit, a heat exchange and cooling unit, a gas distribution unit, a control unit, a deep flue gas purification module, and at least one photosynthetically active radiation sensor. The deep flue gas purification module is connected between the heat exchange and cooling unit and the gas distribution unit to remove harmful substances from the combustion flue gas. The photosynthetically active radiation sensor monitors the light intensity of the crop canopy. The control unit is electrically connected to the photosynthetically active radiation sensor, the combustion engine unit, and the gas distribution unit, and dynamically activates or disables a feedback control loop based on CO2 concentration according to a comparison between the light intensity and a preset threshold, thereby controlling the operating state of the combustion engine unit and the CO2 output of the gas distribution unit. This invention introduces a photosynthetically active radiation sensor and establishes a feedback control mechanism to synchronize CO2 application with the real-time photosynthetic needs of the crop canopy, avoiding ineffective supply under low light conditions and improving CO2 utilization efficiency. At the same time, by setting up a deep flue gas purification module, harmful substances in combustion flue gas are effectively removed, ensuring the physiological safety of crops, thereby achieving precise, safe and efficient CO2 application in greenhouses. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a functional structure diagram of the greenhouse CO2 precision application system based on canopy photosynthetic requirements provided in this embodiment of the invention; Figure 2 This is a layout diagram of the greenhouse CO2 precision application system based on canopy photosynthetic requirements provided in an embodiment of the present invention; Figure 3 This is a flowchart of the light-CO2 linkage control logic provided in an embodiment of the present invention; Figure 4 This is one of the flowcharts of the greenhouse CO2 precision application method based on canopy photosynthetic requirements provided in the embodiments of the present invention; Figure 5This is the second flowchart of the greenhouse CO2 precision application method based on canopy photosynthetic requirements provided in the embodiments of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0018] Figure 1 A flowchart of a greenhouse CO2 precision application system based on canopy photosynthetic requirements provided in an embodiment of the present invention is shown below. Figure 1 As shown, the greenhouse CO2 precision application system based on canopy photosynthetic demand provided in this embodiment of the invention includes: The combustion unit 101, heat exchange and cooling unit 102, gas distribution unit 103, control unit 104, flue gas deep purification module 105, and at least one photosynthetically active radiation sensor 106; in, The flue gas deep purification module 105 is connected between the heat exchange and cooling unit 102 and the gas distribution unit 103, and is used to remove harmful substances from the combustion flue gas. The photosynthetically active radiation sensor 106 is used to monitor the light intensity of the crop canopy. The control unit 104 is electrically connected to the photosynthetically active radiation sensor 106, the burner unit 101, and the gas distribution unit 103, respectively, and is used to dynamically activate or disable the feedback control loop based on CO2 concentration according to the comparison result of the light intensity and the preset threshold, so as to control the operating state of the burner unit 101 and the CO2 output of the gas distribution unit 103.

[0019] In this embodiment of the invention, the combustion unit 101 uses kerosene as fuel to generate CO2-rich flue gas through combustion, providing a CO2 gas source for the system. The carbon dioxide concentration range is, for example, 500 ppm to 1500 ppm, and the preset threshold for photosynthetically active radiation is, for example, 200 μmol / m³. 2 / s.

[0020] Traditional methods of CO2 enhancement, including the use of liquefied CO2 cylinders and fuel combustion, suffer from high costs, uneven distribution, high-temperature hazards, and poor control precision, making it difficult to achieve precise, on-demand enhancement. While existing localized CO2 enhancement technologies can reduce gas waste, their control logic often relies on fixed-time programs or single CO2 concentration threshold feedback, failing to achieve real-time linkage with light intensity. This results in minimal CO2 enhancement under low light conditions, easily leading to resource waste. Furthermore, the flue gas produced by fuel combustion may contain trace amounts of harmful substances such as nitrogen oxides and incompletely burned hydrocarbons, posing potential physiological risks when directly applied to the crop canopy. Finally, they cannot achieve differentiated control based on uneven light distribution within greenhouses, making it difficult to maximize resource utilization efficiency.

[0021] The greenhouse CO2 precision application system based on canopy photosynthetic demand provided in this invention includes a burner unit, a heat exchange and cooling unit, a gas distribution unit, a control unit, a deep flue gas purification module, and at least one photosynthetically active radiation sensor. The deep flue gas purification module is connected between the heat exchange and cooling unit and the gas distribution unit to remove harmful substances from the combustion flue gas. The photosynthetically active radiation sensor monitors the light intensity of the crop canopy. The control unit is electrically connected to the photosynthetically active radiation sensor, the burner unit, and the gas distribution unit, and dynamically activates or disables a feedback control loop based on CO2 concentration according to a comparison between the light intensity and a preset threshold, thereby controlling the operating state of the burner unit and the CO2 output of the gas distribution unit. This invention introduces a photosynthetically active radiation sensor and establishes a feedback control mechanism to synchronize CO2 application with the real-time photosynthetic needs of the crop canopy, avoiding ineffective supply under low light conditions and improving CO2 utilization efficiency. At the same time, by setting up a deep flue gas purification module, harmful substances in combustion flue gas are effectively removed, ensuring the physiological safety of crops, thereby achieving precise, safe and efficient CO2 application in greenhouses.

[0022] Based on any of the above embodiments, the greenhouse CO2 precision application system based on canopy photosynthetic demand provided by this invention further includes at least one canopy temperature sensor and at least one leaf area index (LAI) detection module. The canopy temperature sensor is deployed at the height of the crop canopy for real-time monitoring of the canopy temperature; the LAI detection module is used to acquire the leaf area index of the crop canopy. The control unit is electrically connected to both the canopy temperature sensor and the LAI detection module, and is used to dynamically calculate the target CO2 concentration based on a comprehensive judgment of the light intensity, the canopy temperature, and the LAI.

[0023] In some embodiments of the present invention, the control unit is configured to perform multi-factor weighted fusion judgment, that is, to preset corresponding weight coefficients for light intensity, canopy temperature, and leaf area index, wherein the weight coefficients reflect the degree of influence of each factor on the CO2 demand of crop photosynthesis. The control unit calculates a comprehensive demand index by weighting the ratio of the real-time monitoring value of each factor to its respective preset benchmark value, combined with the corresponding weight coefficient, and then dynamically calculates the target CO2 concentration based on the comprehensive demand index. At the same time, the control unit also performs independent threshold judgment on each factor: when the real-time monitoring value of any factor exceeds its preset normal working range, the system suspends the CO2 increase in the corresponding zone or reduces the target CO2 concentration; when all factors are within their respective preset normal working ranges, the feedback control loop based on CO2 concentration is activated, and the CO2 supply is adjusted according to the deviation between the real-time monitored CO2 concentration and the target CO2 concentration.

[0024] Through the above-mentioned multi-factor weighted fusion judgment, the embodiments of the present invention can more precisely quantify the real-time photosynthetic demand of crop canopy, avoid ineffective application under photosynthetic-limited conditions, and further improve CO2 utilization efficiency.

[0025] Based on any of the above embodiments, the flue gas deep purification module includes at least a primary catalytic oxidizer and a primary selective adsorption filter; The catalytic oxidizer is used to convert carbon monoxide and incompletely burned hydrocarbons in flue gas into carbon dioxide and water. The selective adsorption filter is used to adsorb and remove nitrogen oxides.

[0026] In this embodiment of the invention, a deep flue gas purification module is added between the heat exchange and cooling unit and the gas distribution unit to ensure that the gas finally delivered to the crop canopy is a mixture of high-purity CO2 and air.

[0027] Based on any of the above embodiments, the gas distribution unit is divided into multiple independently controllable zones, each zone being equipped with an independent control valve and a corresponding photosynthetically active radiation sensor. The control unit is also used to perform differentiated CO2 supply control for each zone based on the light intensity in different areas of the greenhouse.

[0028] In this embodiment of the invention, the gas distribution unit includes a main air duct and a plurality of sub-air ducts branching off from the main air duct. Each zone corresponds to at least one sub-air duct, and the outlet of the sub-air duct extends into the crop canopy or is placed outside the cotyledons.

[0029] In this embodiment of the invention, the outlet diameter of the sub-duct is, for example, 41 mm. Each zone corresponds to an area with similar light intensity within the greenhouse. CO2 is precisely delivered to each zone through a zone control valve group.

[0030] In this embodiment of the invention, the control unit is further configured to perform differentiated CO2 supply control for each zone based on the light intensity in different areas of the greenhouse, including: When the light intensity is lower than the preset threshold, the CO2 application to the corresponding zone is paused; When the light intensity is higher than the preset threshold and the CO2 concentration is lower than the preset target value, the CO2 increase in the corresponding zone is activated.

[0031] Based on any of the above embodiments, the greenhouse CO2 precision application system based on canopy photosynthetic requirements also includes a carbon monoxide alarm, which is connected to the control unit. The carbon monoxide alarm is used to detect carbon monoxide concentration; The control unit is also used to automatically cut off the operation of the burner unit and issue an alarm signal when the carbon monoxide concentration detected by the carbon monoxide alarm exceeds a preset safety threshold.

[0032] Based on any of the above embodiments, the heat exchange and cooling unit includes a blower and a heat exchanger, used to cool the high-temperature flue gas generated by combustion to low-temperature CO2 gas with a temperature difference between the flue gas and the internal temperature of the greenhouse within a preset range.

[0033] In this embodiment of the invention, the heat exchange and cooling unit is connected to the combustion unit and includes a blower and a heat exchanger. It is used to forcibly cool the high-temperature flue gas generated by combustion, reducing its temperature to a level similar to the ambient temperature inside the greenhouse, with a difference within ±5°C, forming low-temperature CO2 gas, and avoiding heat stress on crops caused by high-temperature flue gas.

[0034] Based on any of the above embodiments, the control unit includes a CO2 control panel, environmental sensors including but not limited to a CO2 concentration sensor, a photosynthetically active radiation sensor, and a CO alarm, supports IoT communication, and is electrically connected to each unit of the system. The specific configuration is as follows: An integrated photosynthetically active radiation sensor is used only when the canopy light intensity is above the crop light compensation point, for example, greater than 200 μmol / m². 2The feedback control loop based on CO2 concentration is activated only when the light intensity is below a certain threshold (e.g., 0.5 m / s). When the light intensity is below this threshold, the system automatically pauses the application of CO2, achieving strict synchronization between CO2 supply and the actual photosynthetic capacity of the crop. This embodiment of the invention combines an IoT architecture with a cloud platform, enabling the system to have remote monitoring, big data optimization, and predictive maintenance capabilities. It can adaptively adjust parameters according to crop growth stages and changes in the external environment, conforming to the development trend of smart agriculture and possessing a long technology lifecycle.

[0035] It receives signals from photosynthetically active radiation sensors and CO2 concentration sensors deployed in each zone, and independently controls each zone based on a preset greenhouse light distribution model. Zones with sufficient light will increase CO2 supply as needed, while areas with weak light or shade will reduce or stop the supply.

[0036] It can automatically start or stop the application of fuel according to the preset sunrise and sunset times, within a specific time zone (up to 6) of the day; at the same time, it can execute an intermittent operation mode, periodically starting and stopping the burner according to the concentration to save fuel.

[0037] It integrates a CO alarm, which automatically shuts off the device and triggers an alarm when the carbon monoxide concentration exceeds the standard; it also supports signal linkage with external environmental control systems.

[0038] Operational data such as fuel efficiency, CO2 concentration, light intensity, and equipment status can be uploaded to the cloud platform. The platform uses big data analysis to dynamically optimize control parameters and achieve predictive maintenance, issuing early warnings before equipment performance deteriorates or malfunctions.

[0039] The embodiments of the present invention are for tomato greenhouse cultivation scenarios, and examples are as follows: Select a standard glass greenhouse, such as Figure 2 As shown, the gas distribution unit is divided into three zones: a strong light zone, a medium light zone, and a weak light zone. The strong light zone is located in the south of the greenhouse (where direct sunlight lasts the longest), the medium light zone is located in the middle of the greenhouse, and the weak light zone is located in the north of the greenhouse. Each zone is equipped with one CO2 concentration sensor and one photosynthetically active radiation sensor, with the sensors placed in the middle of the tomato canopy. The combustion unit uses a dedicated burner compatible with JIS No. 1 lamp oil. The heat exchange and cooling unit uses a high-efficiency plate heat exchanger linked with the blower. The flue gas deep purification module incorporates a precious metal catalytic oxidizer and an activated carbon selective adsorption filter. The sub-duct is a 41mm diameter flexible duct, with the outlet located on the outer side of the tomato cotyledons, 10-20cm away from the stem.

[0040] The embodiments of the present invention use low-cost lamp oil as fuel, and the operating cost is far lower than that of liquefied CO2; it integrates multiple energy-saving control modes to further reduce operating costs; at the same time, the structural design is reasonable and can be linked with the existing greenhouse environmental control system, making it easy to modify and widely applicable.

[0041] The target CO2 concentration was set at 1000 ppm on the control unit, with a fluctuation range of 950-1050 ppm, and the photosynthetically active radiation activation threshold was set at 200 μmol / m³. 2 / s, the application time is from 8:00 am to 4:00 pm, and the intermittent control mode is enabled, for example, an adjustment cycle of 15 minutes; the system is bound through the cloud platform to set predictive maintenance early warning parameters.

[0042] After the system starts up, sensors in the three zones monitor CO2 concentration and photosynthetically active radiation intensity in real time, transmitting data to the control unit every 10 seconds. The control unit performs parallel analysis of the data from each zone. For example, at 10:00 AM on a sunny day, the light intensity in the strong light zone is 800 μmol / m². 2 / s, above the threshold; CO2 concentration 920ppm, below the lower limit, indicating the need for additional application; light intensity in the medium-light zone is 500μmol / m². 2 / s, above the threshold, CO2 concentration of 1010ppm within the range, determined that no additional application is needed; light intensity in the low-light zone is 180μmol / m². 2 If the value per second is below the threshold, it is determined that additional application should be suspended.

[0043] The control unit starts the burner unit, which burns lamp oil to produce high-temperature flue gas at a temperature of about 300°C. After being cooled by the heat exchange and cooling unit, the flue gas temperature drops to within ±2°C of the ambient temperature, such as 25°C. Then it enters the flue gas deep purification module, where the catalytic oxidizer converts CO and VOCs in the flue gas into harmless substances, and the adsorption filter removes NOx, ultimately obtaining high-purity, low-temperature CO2 gas.

[0044] The control unit opens the control valve of the high-light zone, and the blower delivers purified CO2 gas to the tomato canopy in the high-light zone through the main duct, zone control valve assembly, and sub-ducts. When the CO2 concentration in the high-light zone rises to 1040 ppm, the control unit controls the burner unit to enter standby mode and operate intermittently. If the light intensity drops instantaneously, when the light intensity in the high-light zone falls below 200 μmol / m², the control unit will shut down the burner. 2 When the concentration reaches / s, immediately close the control valve for that zone and stop applying CO. The CO alarm monitors the greenhouse environment. If the CO concentration exceeds the standard, such as greater than 30ppm, immediately cut off the power to the burner and issue an audible and visual alarm. Check the adsorption status of the purification module daily, replace the adsorbent every 3 months, and replace the antifreeze and CO alarm every 3 years.

[0045] CO2 zoning precision control strategy based on light intensity, such as Figure 3 As shown, the CO2 concentration is not a fixed value, but rather dynamically matched with the light intensity. Specifically: Strong light zone: During the peak photosynthesis period from 9 am to 4 pm, CO2 concentration rapidly increases and is maintained within the target range to maximize photosynthetic efficiency and compensate for the limitation of low atmospheric CO2 concentration on photosynthesis.

[0046] Medium light zone: The increase in CO2 concentration and the duration of its maintenance are both lower than in the strong light zone, with a target value of around 900-950 ppm, achieving a balance between energy saving and efficiency improvement.

[0047] Low-light zones: CO2 concentration is only slightly increased to slightly above atmospheric levels, because photosynthesis is mainly limited by light energy under low light conditions, and the gain from high CO2 concentration is limited, thus saving on fertilizer consumption.

[0048] This invention uses the external atmospheric baseline as the starting reference point for system regulation. Maintaining this optimal range during periods of strong light is key to maximizing the yield and quality-enhancing effects of gas fertilizer. The concentration in all zones increases rapidly in the morning as sunlight intensifies, then gradually decreases in the afternoon as sunlight weakens. At night or when photosynthesis is not occurring, the system typically stops supplying gas, and the concentration returns to atmospheric levels.

[0049] This invention dynamically adjusts resource supply based on the real-time physiological needs of crops, thereby achieving a balance between high yield, high quality, and efficient resource utilization. Even with greenhouse ventilation, the CO2 concentration in the strong light and medium light zones remains stable at 950-1050 ppm, higher than the ambient atmospheric concentration, while there is no ineffective application in the weak light zones. Compared with traditional localized application techniques, fuel consumption is reduced by 32%, the net photosynthetic rate of tomatoes increases by 28%, the yield at harvest increases by 15%, and the sugar content of fruits increases by 8%, without any crop heat stress or damage from harmful gases.

[0050] The embodiments of the present invention can flexibly adjust parameters according to different crops and different greenhouse structures, adapt to various facility cultivation scenarios, and have broad application value.

[0051] The greenhouse CO2 precision application system based on canopy photosynthetic demand provided in this invention achieves precise matching between CO2 application and real-time crop photosynthetic needs, avoiding ineffective application under low light conditions; ensures the safety of combustion flue gas composition, eliminating the potential physiological impact of harmful substances on crops; and enables differentiated and precise control of light distribution within the greenhouse, further improving resource utilization efficiency, ultimately increasing CO2 utilization efficiency, promoting crop photosynthesis, increasing yield, and reducing operating costs and energy consumption. Through a "light-CO2 linkage feedback" control algorithm, CO2 supply is upgraded from timed and quantitative to on-demand real-time supply, completely avoiding ineffective application under low light conditions, achieving a theoretically high resource utilization efficiency, and further reducing energy consumption by more than 30%. The addition of a deep flue gas purification module eliminates the potential stress risk of harmful gases in combustion flue gas on crops, making the system applicable to high-value economic crops sensitive to gas environments, thus expanding its application scope. By maintaining a suitable CO2 concentration in the canopy area, crop photosynthesis is effectively promoted, optimizing photosynthetic assimilation effects, and contributing to the simultaneous improvement of crop yield and quality.

[0052] The following describes the greenhouse CO2 precision application method based on canopy photosynthetic demand provided by the present invention. The greenhouse CO2 precision application method based on canopy photosynthetic demand described below can be referred to in correspondence with the greenhouse CO2 precision application system based on canopy photosynthetic demand described above.

[0053] Figure 4 A flowchart of a greenhouse CO2 precision application method based on canopy photosynthetic requirements provided in an embodiment of the present invention is shown below. Figure 4 As shown, the greenhouse CO2 precision application method based on canopy photosynthetic requirements provided by this embodiment of the invention includes: Step 401: Monitor the photosynthetically active radiation intensity and CO2 concentration of the crop canopy in real time; Step 402: Determine whether the photosynthetically active radiation intensity is higher than a preset threshold; Step 403: When the photosynthetically active radiation intensity is higher than the preset threshold, the monitored CO2 concentration is compared with the preset target concentration, and the operating status of the burner unit and the CO2 output of the gas distribution unit are controlled according to the comparison result.

[0054] In this embodiment of the invention, zoning is performed before monitoring is started; The CO2 concentration and light intensity are monitored in real time by environmental sensors in each zone and fed back to the control unit to adjust the operating status of the combustion unit corresponding to each zone and the CO2 output of the gas distribution unit.

[0055] In this embodiment of the invention, before controlling the CO2 output of the gas distribution unit, the method further includes: The flue gas generated from combustion is subjected to cooling and deep purification treatment in sequence. The deep purification treatment includes a catalytic oxidation step and a selective adsorption step to remove carbon monoxide, nitrogen oxides and incompletely burned hydrocarbons from the flue gas.

[0056] Based on any of the above embodiments, the greenhouse CO2 precision application method based on canopy photosynthetic demand provided by the present invention specifically includes the following steps: (1) Establish a greenhouse light distribution map, divide the gas distribution unit into several zones with similar light intensities, and calibrate the sensor positions and control parameters of each zone.

[0057] (2) Set the target CO2 concentration, such as 500ppm to 1500ppm, preferably around 1000ppm, on the control unit, and set the application time zone, light activation threshold, and whether to enable intermittent control mode.

[0058] (3) After the control unit is started, it monitors the CO2 concentration and photosynthetically active radiation intensity of the canopy of each zone in parallel, collects environmental data in real time and transmits it to the control unit.

[0059] (4) For any partition, the control unit makes a dual judgment through the core algorithm: first, it judges whether the photosynthetically effective radiation intensity is higher than the preset threshold. If it is lower than the threshold, the CO2 application in the partition is suspended. If it is higher than the threshold, it judges whether the CO2 concentration in the partition is lower than the target lower limit, and decides whether to start the CO2 application in the partition.

[0060] (5) The control unit starts the burner unit according to the decision result, and burns lamp oil to produce high temperature flue gas.

[0061] (6) The high-temperature flue gas is rapidly cooled by the heat exchange and cooling unit to obtain low-temperature CO2 gas; then the low-temperature CO2 gas is sent to the flue gas deep purification module, and after passing through catalytic oxidation and selective adsorption filtration, harmful pollutants are removed to obtain high-purity low-temperature CO2 gas.

[0062] (7) The control unit controls the zone control valve group, and delivers the purified high-purity low-temperature CO2 gas through the sub-air pipe of the gas distribution unit to the zone with additional application needs, directly to the local area of ​​the crop canopy.

[0063] (8) The CO2 concentration and light intensity are monitored in real time by the environmental sensors of each zone, and the signals are fed back to the control unit. The control unit adjusts the operating status of the burner and the zone control valve group to stabilize the actual CO2 concentration of each zone near the set value.

[0064] (9) The system operation data is uploaded to the cloud platform in real time for remote monitoring, data analysis and parameter optimization; the CO alarm continuously monitors environmental safety and regularly replaces consumables such as antifreeze, CO alarm, and adsorbent.

[0065] like Figure 5 As shown, a light intensity threshold and a target CO2 concentration range are set. First, it is determined whether the current light intensity has reached the effective threshold for initiating photosynthesis. Only when light is sufficient will increasing CO2 application be meaningful for increasing yield. If light is insufficient, the system suspends gas supply to avoid resource waste. Under the premise of sufficient light, it is further determined whether the current CO2 concentration is below the optimal lower limit required for crop growth. If it is within the target range, it is maintained; if it is below the lower limit, additional application is initiated. After initiating additional application, the system dynamically adjusts the output of the gas supply equipment (such as burner power and valve opening) based on the deviation between the real-time monitored CO2 concentration and the target value, achieving precise and stable concentration control.

[0066] The greenhouse CO2 precision application method based on canopy photosynthetic needs provided in this invention couples CO2 application with the actual needs of crop photosynthesis and automatically shuts off when not needed, thereby maximizing energy and resource utilization efficiency while ensuring increased yield.

[0067] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0068] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the parts that contribute to the related technology, can be embodied in the form of software products. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A greenhouse CO2 precision application system based on canopy photosynthetic requirements, characterized in that, include: Combustion unit, heat exchange and cooling unit, gas distribution unit, control unit, flue gas deep purification module, and at least one photosynthetically active radiation sensor; in, The flue gas deep purification module is connected between the heat exchange and cooling unit and the gas distribution unit, and is used to remove harmful substances from the combustion flue gas. The photosynthetically active radiation sensor is used to monitor the light intensity of the crop canopy. The control unit is electrically connected to the photosynthetically active radiation sensor, the combustion engine unit, and the gas distribution unit, respectively, and is used to dynamically activate or disable the feedback control loop based on CO2 concentration according to the comparison result of the light intensity and the preset threshold, so as to control the operating status of the combustion engine unit and the CO2 output of the gas distribution unit.

2. The greenhouse CO2 precision application system based on canopy photosynthetic demand according to claim 1, characterized in that, The flue gas deep purification module includes at least a primary catalytic oxidizer and a primary selective adsorption filter; The catalytic oxidizer is used to convert carbon monoxide and incompletely burned hydrocarbons in flue gas into carbon dioxide and water. The selective adsorption filter is used to adsorb and remove nitrogen oxides.

3. The greenhouse CO2 precision application system based on canopy photosynthetic demand according to claim 1, characterized in that, The gas distribution unit is divided into multiple independently controllable zones, each zone being equipped with an independent control valve and a corresponding photosynthetically active radiation sensor. The control unit is also used to perform differentiated CO2 supply control for each zone based on the light intensity in different areas of the greenhouse.

4. The greenhouse CO2 precision application system based on canopy photosynthetic demand according to claim 3, characterized in that, The gas distribution unit includes a main air duct and multiple sub-air ducts branching off from the main air duct. Each zone corresponds to at least one sub-air duct, and the outlet of the sub-air duct extends into the crop canopy or is placed on the outside of the cotyledons.

5. The greenhouse CO2 precision application system based on canopy photosynthetic demand according to claim 3, characterized in that, The control unit is also used to perform differentiated CO2 supply control for each zone based on the light intensity in different areas of the greenhouse, including: When the light intensity is lower than the preset threshold, the CO2 application to the corresponding zone is paused; When the light intensity is higher than the preset threshold and the CO2 concentration is lower than the preset target value, the CO2 increase in the corresponding zone is activated.

6. The greenhouse CO2 precision application system based on canopy photosynthetic demand according to claim 1, characterized in that, It also includes a carbon monoxide alarm, which is connected to the control unit; The carbon monoxide alarm is used to detect carbon monoxide concentration; The control unit is also used to automatically cut off the operation of the burner unit and issue an alarm signal when the carbon monoxide concentration detected by the carbon monoxide alarm exceeds a preset safety threshold.

7. The greenhouse CO2 precision application system based on canopy photosynthetic demand according to claim 1, characterized in that, The heat exchange and cooling unit includes a blower and a heat exchanger, used to cool the high-temperature flue gas generated by combustion to low-temperature CO2 gas with a temperature difference between the flue gas and the internal temperature of the greenhouse within a preset range.

8. A method for precise CO2 application in a greenhouse based on canopy photosynthetic demand, applicable to the greenhouse CO2 precision application system based on canopy photosynthetic demand as described in any one of claims 1 to 7, characterized in that, include: Real-time monitoring of photosynthetically active radiation intensity and CO2 concentration in crop canopy; Determine whether the photosynthetically active radiation intensity is higher than a preset threshold; When the photosynthetically active radiation intensity is higher than the preset threshold, the monitored CO2 concentration is compared with the preset target concentration, and the operating status of the burner unit and the CO2 output of the gas distribution unit are controlled according to the comparison result.

9. The method for precise CO2 application in greenhouses based on canopy photosynthetic requirements according to claim 8, characterized in that, Before starting monitoring, zoning should be performed; The CO2 concentration and light intensity are monitored in real time by environmental sensors in each zone and fed back to the control unit to adjust the operating status of the combustion unit corresponding to each zone and the CO2 output of the gas distribution unit.

10. The method for precise CO2 application in greenhouses based on canopy photosynthetic requirements according to claim 8, characterized in that, Before controlling the CO2 output of the gas distribution unit, the following is also included: The flue gas generated from combustion is subjected to cooling and deep purification treatment in sequence. The deep purification treatment includes a catalytic oxidation step and a selective adsorption step to remove carbon monoxide, nitrogen oxides and incompletely burned hydrocarbons from the flue gas.

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