A method and system for intelligent ventilation control for water conservation in grain storage

Abstract

The application provides a kind of intelligent ventilation control method and system of water type for storing grain, and the technical field of storing grain ventilation control, method includes: the temperature difference between the grain pile outlet temperature and the temperature outside the warehouse entrance temperature is calculated, and the humidity difference between the relative humidity outside the warehouse and the relative humidity in the warehouse;Determine whether the temperature difference is greater than the first preset temperature and less than or equal to the second preset temperature, and the grain surface wind pressure is greater than 0;If any condition is not met, control the frequency conversion fan to stop running;If both conditions are met, calculate the humidity correction value according to the value of the humidity difference through the preset nonlinear humidity correction function;The target operating frequency of the frequency conversion fan is calculated by the preset weighted control function;The target operating frequency is output to the frequency conversion fan to drive the fan to run at the frequency;The application provides an intelligent ventilation control method that can balance the heat dissipation demand and water conservation target.

Description

Technical Field

[0001] This invention relates to the field of grain storage ventilation control technology, and in particular to a smart ventilation control method and system for grain storage with water retention. Background Technology

[0002] Traditional grain warehouse ventilation control methods typically employ simple temperature and humidity threshold comparison strategies, such as allowing ventilation only when the outside humidity is lower than the inside humidity. While this rigid control method can prevent grain from absorbing moisture, it can easily lead to excessive water loss in dry regions or seasons, resulting in quality degradation and weight loss. Furthermore, current technology lacks safety interlock judgment regarding wind pressure over the grain surface, making it difficult to prevent the risk of localized mold growth caused by the backflow of hot and humid air. In addition, traditional methods often use on / off fan control, which cannot finely adjust the ventilation intensity based on real-time temperature and humidity differences, resulting in high energy consumption and poor water retention. Therefore, there is an urgent need for an intelligent ventilation control method that can balance heat dissipation requirements with water retention goals. Summary of the Invention

[0003] To address the aforementioned technical problems, the technical solution adopted by this invention is as follows: According to a first aspect of this application, a smart ventilation control method for grain storage and water retention is provided, the method comprising the following steps: Real-time data collection includes grain pile outlet temperature, warehouse inlet temperature, warehouse relative humidity, warehouse relative humidity, and grain surface wind pressure. Calculate the temperature difference between the grain pile outlet temperature and the warehouse inlet temperature, and the humidity difference between the relative humidity outside the warehouse and the relative humidity inside the warehouse; Determine whether the temperature difference is greater than the first preset temperature and less than or equal to the second preset temperature, and whether the grain surface air pressure is greater than 0; if any condition is not met, control the variable frequency fan to stop running. If both conditions are met, a humidity correction value is calculated based on the humidity difference using a preset nonlinear humidity correction function; wherein: when the humidity difference is greater than a second preset threshold, the humidity correction value is 0; when the humidity difference is between a first preset threshold and a second preset threshold, the humidity correction value decreases linearly as the humidity difference increases; when the humidity difference is less than or equal to a first preset threshold, the humidity correction value is a positive number proportional to the absolute value of the humidity difference, and the proportionality coefficient of this positive number is less than the absolute value of the linear decrease coefficient of the humidity difference within the range of the first preset threshold and the second preset threshold. Based on the temperature difference and the humidity correction value, the target operating frequency of the variable frequency fan is calculated through a preset weighted control function; the weighted control function is the sum of the product of the temperature difference and the first coefficient plus the product of the humidity correction value and the second coefficient, and then multiplied by the system gain coefficient. The target operating frequency is output to the variable frequency fan, driving the fan to operate at that frequency.

[0004] According to another aspect of this application, a grain storage and water retention intelligent ventilation control system is also provided, comprising: The parameter acquisition module is used to collect real-time data on grain pile outlet temperature, warehouse inlet temperature, warehouse relative humidity, warehouse relative humidity, and grain surface wind pressure. The data processing module, connected to the parameter acquisition module, is used to calculate the temperature difference between the grain pile outlet temperature and the warehouse inlet temperature, as well as the humidity difference between the warehouse outer relative humidity and the warehouse inner relative humidity. The intelligent controller is connected to the data processing module and the parameter acquisition module respectively. The intelligent controller internally stores the first preset temperature, the second preset temperature, the first preset threshold, the second preset threshold, the nonlinear humidity correction function, and the weighted control function. The intelligent controller is used to: determine whether the temperature difference is greater than the first preset temperature and less than or equal to the second preset temperature and the grain surface wind pressure is greater than 0 at the same time; if any condition is not met, a stop command is output; if both conditions are met, a humidity correction value is calculated based on the humidity difference using the nonlinear humidity correction function, and then a target operating frequency is calculated using the weighted control function, and the target operating frequency is output. The variable frequency fan is electrically connected to the intelligent controller and is used to receive the stop command or the target operating frequency, and stop running or run at the target operating frequency accordingly.

[0005] The present invention has at least the following beneficial effects: The intelligent ventilation control method for grain storage with water retention of this invention achieves flexible ventilation control that slows down ventilation as humidity increases outside the storage area compared to inside by introducing a nonlinear humidity correction function. This utilizes the grain pile's own moisture absorption and buffering capacity for passive micro-moisture absorption, while linearly reducing the fan frequency to prevent excessive moisture. Simultaneously, when the outside environment is dry, a small proportional coefficient is used to calculate the humidity correction value, actively suppressing grain water loss caused by excessive ventilation, truly realizing an intelligent control strategy of "passive micro-moisture absorption and active strong water retention." By setting dual safety interlocking conditions of temperature difference and wind pressure, the fan is ensured to start only when heat dissipation demand is met and the airflow direction is correct, eliminating the risk of hot and humid air backflow. A weighted control function is used to dynamically calculate the target frequency of the variable frequency fan, which can smoothly adjust the ventilation intensity according to real-time changes in temperature and humidity differences, significantly reducing energy consumption and extending fan life compared to traditional on / off control. Furthermore, each key coefficient can be calibrated according to the equilibrium relative humidity characteristics of different grain varieties, exhibiting good adaptability. Attached Figure Description

[0006] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0007] Figure 1 A flowchart of a grain storage and water-retaining intelligent ventilation control method provided in an embodiment of the present invention. Detailed Implementation

[0008] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0009] It should be noted that, based on this disclosure, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Furthermore, this device and / or practice the method can be implemented using other structures and / or functionalities besides one or more of the aspects set forth herein.

[0010] The following will refer to Figure 1 The flowchart shown is for a grain storage and water conservation type intelligent ventilation control method, which introduces such a method.

[0011] The intelligent ventilation control method for grain storage and water retention can include the following steps: The S100 collects real-time data on grain pile outlet temperature, warehouse inlet temperature, warehouse relative humidity, warehouse relative humidity, and grain surface wind pressure.

[0012] In this embodiment, a first temperature and humidity sensor is installed 1-2 meters outside the storage area, at a distance of 1-2 meters from the air inlet, to collect the inlet temperature t1 (°C) and relative humidity h1 (%RH) outside the storage area. A second temperature and humidity sensor is buried inside the grain pile, 0.5-1.0 meters below the grain surface, to collect the outlet temperature t2 (°C) and relative humidity h2 (%RH) inside the storage area. A micro-differential pressure sensor is installed 10-20 centimeters above the grain surface to collect the wind pressure P (Pa) on the grain surface. All sensors collect data in real time at a sampling frequency of 0.5-2.0 Hz, and the data is processed by median filtering to eliminate transient noise.

[0013] By deploying high-precision sensors at key locations and employing filtering, the accuracy and reliability of the raw data upon which subsequent calculations are based are ensured, avoiding misjudgments caused by sensor noise or improper installation, thus laying a data foundation for refined intelligent control.

[0014] S200, calculate the temperature difference between the grain pile outlet temperature and the warehouse inlet temperature, and the humidity difference between the warehouse relative humidity and the warehouse relative humidity.

[0015] In this embodiment, the data processing module calculates the temperature difference ΔT and humidity difference ΔH according to the following formulas: ΔT = t2 - t1; ΔH = h1 - h2; where ΔH is expressed as a percentage (e.g., 5 represents 5%). The calculation cycle is synchronized with the sampling cycle, and ΔT and ΔH are updated immediately after each new data is obtained.

[0016] By calculating the difference, absolute temperature and humidity are converted into relative differences, which directly reflect the driving force of the exchange between the grain pile and the outside world. This provides a simple and effective characteristic quantity for subsequent judgment of the necessity and intensity of ventilation, and reduces the complexity of the control logic.

[0017] S300, determine whether the temperature difference is greater than the first preset temperature and less than or equal to the second preset temperature, and the grain surface wind pressure is greater than 0; if any condition is not met, control the variable frequency fan to stop running.

[0018] Furthermore, the first preset temperature is 0°C, the second preset temperature is 8°C; the first preset threshold is 0%, and the second preset threshold is 10%.

[0019] In this embodiment, it is first determined whether the following two conditions are met simultaneously: (1) The first preset temperature ≤ ΔT ≤ the second preset temperature, where the first preset temperature is set to 0℃ and the second preset temperature is set to 8℃. ΔT > 0 indicates that the temperature of the grain pile is higher than that of the outside, and there is a need to dissipate sensible heat; ΔT ≤ 8℃ is to prevent the temperature difference from being too large, which may cause condensation at the bottom of the grain pile - experiments show that when ΔT > 8℃, ventilation may allow cold air to enter the grain pile and cause local moisture condensation.

[0020] (2) Grain surface air pressure P > 0. P > 0 means that the suction force generated by the operation of the fan creates a negative pressure on the grain surface, and the airflow direction is from bottom to top (air enters from the bottom of the grain pile and exits from the grain surface). When P ≤ 0, backflow of air may occur due to fan failure, air duct blockage, or reverse installation, forcibly stopping ventilation.

[0021] If any condition is not met, the controller outputs a frequency of 0 to the variable frequency fan, and the fan stops running. This judgment is executed once in each control cycle (e.g., 1 second).

[0022] By setting up dual safety interlock conditions, the risk of condensation caused by excessive temperature difference or backflow of hot and humid air due to abnormal wind pressure is eliminated while ensuring effective heat dissipation. This significantly improves the safety of grain warehouse ventilation and avoids the occurrence of localized mold growth accidents.

[0023] Furthermore, the first preset temperature ΔT_min and the second preset temperature ΔT_max can also be dynamically determined using the following methods: ΔT_min is used to determine whether the basic heat dissipation requirements for initiating ventilation are met. If ΔT ≤ ΔT_min, the grain pile temperature is not higher than the outside temperature, ventilation cannot lower the temperature, and ventilation should be prohibited.

[0024] The steps to determine ΔT_min are as follows: Set initial value: Let ΔT_min = 0℃. This value is theoretically the minimum heat dissipation driving force boundary.

[0025] Grain pile temperature gradient measurement: At least three temperature sensors are arranged vertically (from the grain surface to the bottom of the grain pile) inside the grain silo (0.5m from the grain surface, in the middle of the grain pile, and 0.5m from the bottom). The temperature of each layer is recorded continuously for 24 hours under natural conditions.

[0026] To determine if a "false temperature difference" exists: When the temperature at the top of the grain pile is lower than the temperature at the bottom (i.e., a normal grain condition of "cold at the top and hot at the bottom"), ΔT = t2 (outlet temperature, usually taken at 0.5-1.0 meters below the grain surface) - t1 (outlet temperature). Even if t1 is slightly higher than t2, there may still be upward heat flow inside the grain pile due to its own respiration. To avoid being overly conservative, ΔT_min can be set to 0℃, meaning it can be activated as long as the grain pile outlet temperature is ≥ the outside temperature. For more stringent energy-saving control, ΔT_min can be adjusted to 0.5~1.0℃.

[0027] Verify the rationality of ΔT_min: Select several weather days (daily average temperature 0-2℃ higher than grain pile temperature) and conduct simulation control with ΔT_min=0℃ and ΔT_min=1℃ respectively. Observe the cumulative ventilation duration and grain pile temperature changes. If ΔT_min=0℃ leads to frequent ineffective ventilation (no significant decrease in grain pile temperature after operation), then ΔT_min should be increased to 0.5-1.0℃. Under normal circumstances, ΔT_min fixed at 0℃ is sufficient to meet the requirements.

[0028] ΔT_max is used to prevent the risk of condensation inside the grain pile due to excessive temperature difference. When ΔT > ΔT_max, even if ventilation is activated, condensation may still occur as cold air enters the grain pile and mixes with the warm and humid air inside, leading to localized mold growth.

[0029] The steps to determine ΔT_max are as follows: Determine the dew point temperature of the grain pile: Calculate the dew point temperature t_d based on the average internal temperature t_avg and average relative humidity h_avg (which can be obtained from sensors inside the grain pile). Calculation formula (Magnus approximation): ; in, For water, the commonly used parameters are a=17.27 and b=237.7℃.

[0030] Determine the upper limit of the safe temperature difference: Let the inlet temperature outside the storage area be t1. Then, the risk of "contact condensation" mainly occurs on the surface of the grain pile. When t1 is significantly lower than the dew point inside the grain pile, the entry of cold air will cause the surface temperature of the grain grains to drop below the dew point, leading to condensation. Engineering experience shows that when the difference between t2 (the outlet temperature of the grain pile) and t1 is greater than 8~10℃, the risk of condensation increases significantly. This can be accurately calibrated through the following steps: In a small laboratory simulation chamber, the grain pile is heated to a typical storage temperature (e.g., 25°C), maintaining an internal relative humidity of 65%–75%. Cold air at different temperatures (ΔT = 5°C, 6°C, 7°C, 8°C, 9°C, 10°C respectively) is introduced and continuously ventilated for 2 hours. Immediately after shutdown, the surface of the grain pile (10-20 cm above the air inlet) is checked for visible condensation or an abnormal increase in moisture content. The minimum ΔT at which condensation occurs is recorded as ΔT_critical. ΔT_max = ΔT_critical - 1°C (keeping a safety margin).

[0031] For common grains (wheat, corn, rice), under normal storage conditions (grain temperature 15-25℃, relative humidity 60-75%), the recommended range for ΔT_max is 6-10℃. In most cases, 8℃ is taken as the general safety upper limit. If the grain silo is located in a high-humidity area or the initial moisture content of the grain pile is high, ΔT_max should be appropriately reduced to 6℃; if the grain pile is extremely dry (moisture content below the lower limit of the safety standard), it can be appropriately relaxed to 10℃.

[0032] On-site verification and adjustment: After installing the system, record data for a complete season in a real warehouse. If there are no condensation alarms (a condensation sensor can be installed below the grain surface or additional moisture detection points can be added), the current ΔT_max can be maintained; if a condensation event occurs, ΔT_max needs to be lowered by 1-2℃ and re-verified.

[0033] The ΔT_min and ΔT_max determined by the above method ensure the effectiveness of ventilation in heat dissipation and avoid the risk of condensation caused by excessive temperature difference, thus providing reliable safety boundary parameters for the intelligent ventilation control method for grain storage and water retention.

[0034] S400, if both conditions are met, then a humidity correction value is calculated based on the humidity difference using a preset nonlinear humidity correction function; wherein: when the humidity difference is greater than a second preset threshold, the humidity correction value is 0; when the humidity difference is between a first preset threshold and a second preset threshold, the humidity correction value decreases linearly as the humidity difference increases; when the humidity difference is less than or equal to a first preset threshold, the humidity correction value is a positive number proportional to the absolute value of the humidity difference, and the proportionality coefficient of this positive number is less than the absolute value of the linear decrease coefficient of the humidity difference within the range of the first preset threshold and the second preset threshold.

[0035] Furthermore, the nonlinear humidity correction function Φ(ΔH) satisfies the following relationship: When ΔH>10%, Φ(ΔH)=0; When 0%<ΔH≤10%, Φ(ΔH)=k1×(10%-ΔH); When ΔH≤0%, Φ(ΔH)=k2×|ΔH|; Wherein, ΔH is the humidity difference, k1 is the absolute value of the linear reduction coefficient, and k2 is the proportional coefficient, and satisfies 0 < k2 < k1.

[0036] Furthermore, the ratio of k1 to k2 ranges from k2 / k1 ∈ (0, 0.5).

[0037] In this embodiment, when both conditions in S300 are met, the humidity correction value is calculated. The humidity correction function Φ(ΔH) is defined as follows: When ΔH > 10%, Φ(ΔH) = 0. At this point, the humidity outside the warehouse is more than 10 percentage points higher than that inside. Direct ventilation will cause the grain to absorb moisture rapidly and exceed the standard, so it is completely prohibited.

[0038] When 0% < ΔH ≤ 10%, Φ(ΔH) = k1 × (10% - ΔH). Here, k1 is the absolute value of the linear reduction coefficient, ranging from 0.5 to 1.0, with a typical value of 0.8. This function causes the value of Φ to decrease linearly to 0 as ΔH increases, achieving a "wetter, slower" control effect.

[0039] When ΔH ≤ 0%, Φ(ΔH) = k2 × |ΔH|. Here, k2 is a proportionality coefficient, satisfying 0 < k2 < k1, with a typical proportion k2 / k1 = 0.375 (i.e., k2 = 0.3). This design ensures that the Φ value increases linearly with the degree of dryness when drying outside the warehouse, but the increase is less than the decrease under the same absolute humidity difference (1% vs. -1%), thus actively suppressing water loss caused by excessive ventilation.

[0040] In this embodiment, the values ​​of k1 and k2 were obtained through experiments on the equilibrium relative humidity characteristics of grain varieties. Taking wheat as an example: at 25℃, wheat samples were placed in environments with different relative humidity levels to measure their equilibrium moisture content, obtaining hygroscopic isotherms. The experiment showed that when the external humidity was 10% higher than the internal humidity, the moisture content of wheat increased by 1.2% within 48 hours (exceeding the safety limit); when the external humidity was 5% higher than the internal humidity, the moisture content increased by only 0.4%, which is within an acceptable range. Through linear interpolation, k1=0.8 was set to linearly reduce Φ from 8 to 0 within the ΔH=0%~10% range. For the dry side (ΔH≤0%), referring to the desorption isotherm of wheat, the desorption rate under the same absolute humidity difference (e.g. -5%) is about 40% of the moisture absorption rate. Therefore, we take k2=0.3 (k2 / k1=0.375) so that Φ is only 3 when ΔH=-10%, while Φ=0 when the same positive difference (ΔH=10%). The directional difference ensures that water retention is prioritized.

[0041] This nonlinear humidity correction function is finely segmented and has a clear physical meaning. When the outside of the warehouse is slightly damp, it allows limited ventilation, but the intensity decreases as the humidity difference increases. It cleverly utilizes the moisture absorption and buffering capacity of the grain pile to achieve "passive micro-moisture absorption". When the outside of the warehouse is dry, it increases the correction value with a small slope to avoid excessive drying. It truly realizes the intelligent control strategy of "passive micro-moisture absorption and active strong water retention".

[0042] S500, based on the temperature difference and the humidity correction value, calculate the target operating frequency of the variable frequency fan through a preset weighted control function; the weighted control function is the sum of the product of the temperature difference and the first coefficient plus the product of the humidity correction value and the second coefficient, and then multiplied by the system gain coefficient. Furthermore, the weighted control function satisfies the following relationship: f = K × (α × ΔT + β × Φ(ΔH)); Where f is the target operating frequency, ΔT is the temperature difference, K is the system gain coefficient, α is the first coefficient, β is the second coefficient, and K, α, and β are all positive real numbers.

[0043] Furthermore, the first coefficient α and the second coefficient β satisfy α / β∈[0.5,2.0].

[0044] In this embodiment, based on ΔT and Φ(ΔH), a weighted linear function is used to calculate the target operating frequency f (unit: Hz) of the fan: f = K × (α × ΔT + β × Φ(ΔH)); where: K is the system gain coefficient, used to map the weighted sum to the operating frequency range of the fan (usually 0~50Hz), with a value range of 0.5~2.0, and a typical value of 1.0. α is the temperature weighting coefficient, with a value range of 0.3~0.7, and a typical value of 0.5, reflecting the importance of heat dissipation requirements. β is the humidity weighting coefficient, with a value range of 0.3~0.7, and a typical value of 0.5, reflecting the importance of water retention constraints. Furthermore, α / β is generally controlled between 0.5 and 2.0 to balance the relative contributions of the two objectives. In this example, α = β = 0.5, and α / β = 1.

[0045] Furthermore, the system gain coefficient K, the first coefficient α, the second coefficient β, the absolute value k1 of the linear reduction coefficient, and the proportional coefficient k2 are all calibrated based on the equilibrium relative humidity characteristics of the stored grain varieties.

[0046] In this embodiment, K, α, and β need to be calibrated according to different grain varieties. The calibration steps include: (1) Conduct multiple ventilation tests on target grain varieties (such as corn and rice) under different temperature and humidity conditions in a small laboratory grain warehouse, while monitoring the changes in grain moisture and the rate of temperature drop.

[0047] (2) Using “water retention rate (minimize water loss)” and “cooling rate” as optimization objectives, the optimal α / β ratio is determined by orthogonal experiment or response surface methodology.

[0048] (3) Based on the actual speed range of the fan (e.g., 0~50Hz), select K such that f does not exceed 50Hz when the maximum temperature difference (8℃) and the maximum humidity correction value (e.g., Φ=3 when ΔH=-10%). That is, K≤50 / (α×8+β×Φ_max).

[0049] (4) The calibrated coefficients are fixed in the controller; they can also be manually corrected through the weight interface during on-site debugging.

[0050] By combining the heat dissipation demand represented by temperature difference and the water retention constraint represented by humidity correction value through a weighted control function, and by calibrating coefficients for different grain varieties, the control strategy can be adaptively adjusted. The dynamically calculated frequency enables smooth speed changes of the fan, avoiding the inrush current and frequent start-stop of on-off control, resulting in significant energy savings and extending the fan's lifespan.

[0051] S600, output the target operating frequency to the variable frequency fan, and drive the fan to operate at that frequency.

[0052] In this embodiment, the intelligent controller outputs the calculated target operating frequency f to the frequency setpoint port of the frequency converter via analog signal (4-20mA or 0-10V) or digital communication (Modbus, CAN). The frequency converter drives the fan motor according to this frequency. If a new frequency is recalculated within the control cycle, the output is updated in real time, forming a closed-loop dynamic adjustment. When condition S300 is not met, the output is 0Hz, and the fan stops.

[0053] By dynamically outputting frequency values ​​in real time, the fan speed is precisely matched to the required ventilation intensity, ensuring both heat dissipation and water retention while minimizing energy consumption. Furthermore, because the frequency adjustment is continuous and smooth, it avoids the impact of frequent fan starts and stops on the power grid and mechanical structure, thus improving system reliability.

[0054] Furthermore, before calculating the target operating frequency, a wind pressure safety interlock step is included: subsequent calculation steps are only allowed when the wind pressure on the grain surface is greater than 0; when the wind pressure on the grain surface is less than or equal to 0, the target operating frequency is forcibly set to 0.

[0055] This wind pressure safety interlock procedure uses a wind pressure of P > 0 on the grain surface as the sole physical condition for calculating the target frequency and allowing the blower to operate. Under any circumstances, if P ≤ 0 is detected (including when the blower is not running, backflow, blockage, sensor malfunction, etc.), the blower will immediately and unconditionally stop. Compared to traditional methods that rely solely on temperature and humidity differences, this procedure adds closed-loop monitoring of the actual airflow direction, ensuring that the blower can only operate when a correct upward airflow is established. This fundamentally avoids serious accidents caused by hot, humid air flowing back into the grain pile, leading to localized heating, mold, or even spontaneous combustion. Simultaneously, this interlock procedure, together with temperature and humidity differences, forms a three-tiered safety protection system (temperature boundary, humidity boundary, and wind pressure boundary), fully guaranteeing grain storage safety.

[0056] Furthermore, although the steps of the method in this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or a step may be broken down into multiple steps.

[0057] In one exemplary embodiment, a grain storage and water retention intelligent ventilation control system is also provided, comprising: The parameter acquisition module is used to collect real-time data on grain pile outlet temperature, warehouse inlet temperature, warehouse relative humidity, warehouse relative humidity, and grain surface wind pressure.

[0058] The data processing module, connected to the parameter acquisition module, is used to calculate the temperature difference between the grain pile outlet temperature and the warehouse inlet temperature, as well as the humidity difference between the warehouse relative humidity and the warehouse relative humidity.

[0059] The intelligent controller is connected to the data processing module and the parameter acquisition module respectively. The intelligent controller internally stores the first preset temperature, the second preset temperature, the first preset threshold, the second preset threshold, the nonlinear humidity correction function, and the weighted control function.

[0060] The intelligent controller is used to: determine whether the temperature difference is greater than the first preset temperature and less than or equal to the second preset temperature and the grain surface wind pressure is greater than 0 at the same time; if any condition is not met, a stop command is output; if both conditions are met, a humidity correction value is calculated based on the humidity difference using the nonlinear humidity correction function, and then a target operating frequency is calculated using the weighted control function, and the target operating frequency is output.

[0061] The variable frequency fan is electrically connected to the intelligent controller and is used to receive the stop command or the target operating frequency, and stop running or run at the target operating frequency accordingly.

[0062] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art should also understand that various modifications can be made to the embodiments without departing from the scope and spirit of the invention.

Claims

1. A smart ventilation control method for grain storage and water retention, characterized in that, Includes the following steps: Real-time data collection includes grain pile outlet temperature, warehouse inlet temperature, warehouse relative humidity, warehouse relative humidity, and grain surface wind pressure. Calculate the temperature difference between the grain pile outlet temperature and the warehouse inlet temperature, and the humidity difference between the relative humidity outside the warehouse and the relative humidity inside the warehouse; Determine whether the temperature difference is greater than the first preset temperature and less than or equal to the second preset temperature, and whether the grain surface air pressure is greater than 0; if any condition is not met, control the variable frequency fan to stop running. If both conditions are met, a humidity correction value is calculated based on the humidity difference using a preset nonlinear humidity correction function; wherein: when the humidity difference is greater than a second preset threshold, the humidity correction value is 0; when the humidity difference is between a first preset threshold and a second preset threshold, the humidity correction value decreases linearly as the humidity difference increases; when the humidity difference is less than or equal to a first preset threshold, the humidity correction value is a positive number proportional to the absolute value of the humidity difference, and the proportionality coefficient of this positive number is less than the absolute value of the linear decrease coefficient of the humidity difference within the range of the first preset threshold and the second preset threshold. Based on the temperature difference and the humidity correction value, the target operating frequency of the variable frequency fan is calculated through a preset weighted control function; the weighted control function is the sum of the product of the temperature difference and the first coefficient plus the product of the humidity correction value and the second coefficient, and then multiplied by the system gain coefficient. The target operating frequency is output to the variable frequency fan, driving the fan to operate at that frequency.

2. The intelligent ventilation control method for grain storage and water retention according to claim 1, characterized in that, The first preset temperature is 0°C, and the second preset temperature is 8°C; the first preset threshold is 0%, and the second preset threshold is 10%.

3. The intelligent ventilation control method for grain storage and water retention according to claim 1 or 2, characterized in that, The nonlinear humidity correction function Φ(ΔH) satisfies the following relationship: When ΔH>10%, Φ(ΔH)=0; When 0%<ΔH≤10%, Φ(ΔH)=k1×(10%-ΔH); When ΔH≤0%, Φ(ΔH)=k2×|ΔH|; Wherein, ΔH is the humidity difference, k1 is the absolute value of the linear reduction coefficient, and k2 is the proportional coefficient, and satisfies 0 < k2 < k1.

4. The intelligent ventilation control method for grain storage and water retention according to claim 3, characterized in that, The ratio of k1 to k2 ranges from k2 / k1 ∈ (0, 0.5).

5. The intelligent ventilation control method for grain storage and water retention according to claim 3, characterized in that, The weighted control function satisfies the following relationship: f = K × (α × ΔT + β × Φ(ΔH)); Where f is the target operating frequency, ΔT is the temperature difference, K is the system gain coefficient, α is the first coefficient, β is the second coefficient, and K, α, and β are all positive real numbers.

6. The intelligent ventilation control method for grain storage and water retention according to claim 5, characterized in that, The first coefficient α and the second coefficient β satisfy α / β∈[0.5,2.0].

7. The intelligent ventilation control method for grain storage and water retention according to claim 1, characterized in that, Before calculating the target operating frequency, a wind pressure safety interlock step is also included: subsequent calculation steps are allowed only when the wind pressure on the grain surface is greater than 0; when the wind pressure on the grain surface is less than or equal to 0, the target operating frequency is forcibly set to 0.

8. The intelligent ventilation control method for grain storage and water retention according to any one of claims 1 to 7, characterized in that, The system gain coefficient K, the first coefficient α, the second coefficient β, the absolute value k1 of the linear reduction coefficient, and the proportional coefficient k2 are all calibrated based on the equilibrium relative humidity characteristics of the stored grain varieties.

9. A grain storage and water-retaining intelligent ventilation control system for implementing the method as described in any one of claims 1 to 8, characterized in that, include: The parameter acquisition module is used to collect real-time data on grain pile outlet temperature, warehouse inlet temperature, warehouse relative humidity, warehouse relative humidity, and grain surface wind pressure. The data processing module, connected to the parameter acquisition module, is used to calculate the temperature difference between the grain pile outlet temperature and the warehouse inlet temperature, as well as the humidity difference between the warehouse outer relative humidity and the warehouse inner relative humidity. The intelligent controller is connected to the data processing module and the parameter acquisition module respectively. The intelligent controller internally stores the first preset temperature, the second preset temperature, the first preset threshold, the second preset threshold, the nonlinear humidity correction function, and the weighted control function. The intelligent controller is used to: determine whether the temperature difference is greater than the first preset temperature and less than or equal to the second preset temperature and the grain surface wind pressure is greater than 0 at the same time; if any condition is not met, a stop command is output; if both conditions are met, a humidity correction value is calculated based on the humidity difference using the nonlinear humidity correction function, and then a target operating frequency is calculated using the weighted control function, and the target operating frequency is output. The variable frequency fan is electrically connected to the intelligent controller and is used to receive the stop command or the target operating frequency, and stop running or run at the target operating frequency accordingly.

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