Dehumidification control method, device and equipment for cold source fresh air handling unit and medium

Abstract

The invention discloses a dehumidification control method, device and equipment of a cold source fresh air handling unit and a medium, and belongs to the field of air conditioner dehumidification control. The method comprises the steps that by collecting return air humidity, return air relative humidity and coil pipe surface temperature, ultra-cooling capacity representing frosting driving force is calculated, and an accumulated frost index is obtained according to an ultra-cooling capacity integral; thirdly, weighting calculation is conducted on the coil pipe temperature, the ultra-cooling capacity, the accumulated frost index and the external temperature risk, a comprehensive frost risk index is obtained, and the defrosting triggering time is judged based on the index and the coil pipe surface temperature change rate; and once triggered, the corresponding defrosting grades are matched according to the super-cooling capacity, the accumulated frost index and the frost risk index, and corresponding operation is executed. According to the invention, the problem of low defrosting efficiency in dehumidification control of the cold source fresh air handling unit in the prior art can be solved.

Description

Technical Field

[0001] This invention relates to the field of dehumidification control, and more particularly to a dehumidification control method, apparatus, equipment, and medium for a cold source fresh air handling unit. Background Technology

[0002] As a component of a centralized air conditioning system, the main function of a chilled air handling unit is to cool the return air through the surface of its coils, causing water vapor in the air to condense and thus regulate the temperature and humidity of the supply air. During dehumidification operation, when the surface temperature of the coils is lower than the dew point temperature of the return air, the water vapor in the air will condense on the coil surface to form liquid water. If the surface temperature of the coils drops further below the freezing point, the condensate will quickly freeze to form a frost layer. The appearance of frost significantly reduces the heat exchange efficiency of the coils, hinders the heat exchange between the air and the refrigerant, leading to a continuous decline in the unit's dehumidification capacity, increased fluctuations in supply air temperature and humidity, and in severe cases, even equipment failures such as abnormal compression cycle, liquid slugging, or coil freezing and cracking. Therefore, effective anti-frost and defrosting mechanisms must be introduced in dehumidification control to ensure that the unit can stably maintain dehumidification efficiency under low temperature and high humidity conditions, while avoiding equipment performance degradation and operational safety hazards caused by frost formation.

[0003] In existing technologies, dehumidification control of cold source fresh air handling units typically uses a single physical threshold as the basis for defrosting triggering. For example, when the coil surface temperature is below a certain fixed temperature value for a certain period of time, the system determines that it has entered a frosting state and starts the defrosting program. Alternatively, during the defrosting process, parameters such as compressor low-pressure and outlet water temperature are monitored to determine whether to exit the defrosting mode. This control method is essentially reactive, lacking dynamic quantitative perception and risk prediction capabilities for the frosting process, and cannot identify risks and take intervention measures in the early stages of frosting. Due to the failure to comprehensively consider the temperature difference accumulation effect between the coil surface and the air dew point, existing technologies are prone to two typical problems: First, frequent unnecessary defrosting is triggered under low-risk conditions, resulting in frequent unit start-stop, cooling loss, and increased fan energy consumption. Second, defrosting response is delayed under high-risk conditions, leading to excessive frost accumulation, requiring high-energy-consuming electric heating or long-term reverse circulation to completely melt it. This not only significantly increases the energy consumption of the defrosting process itself but also leads to increased subsequent dehumidification load and decreased system energy efficiency due to coil thermal inertia. This extensive control strategy cannot achieve a precise match between defrosting timing and defrosting intensity, resulting in low defrosting efficiency of the cold source fresh air unit. Summary of the Invention

[0004] This invention provides a dehumidification control method, device, equipment, and medium for cold source fresh air handling units, which can solve the problem of low defrosting efficiency in the dehumidification control of cold source fresh air handling units in the prior art.

[0005] Firstly, embodiments of the present invention provide a dehumidification control method for a cold source fresh air handling unit, comprising: The return air temperature, return air relative humidity, and coil surface temperature of the cold source fresh air unit were collected. The ultracooling amount used to characterize the frost driving force is calculated based on the return air temperature, the return air relative humidity and the coil surface temperature, and the cumulative frost index used to characterize the frost accumulation effect is determined based on the ultracooling amount. The coil surface temperature, the supercooling amount, the accumulated frost index, and the preset external temperature risk index are weighted according to preset weighting coefficients to obtain a frost risk index used to characterize the overall frost risk. Based on the frost risk index and the coil surface temperature change rate, it is determined whether defrosting is required. If so, based on the supercooling capacity, the accumulated frost index, and the frost risk index, the corresponding defrosting level is matched from the preset defrosting classification rules, and the defrosting operation corresponding to the defrosting level is performed on the cold source fresh air unit; wherein, the coil surface temperature change rate is calculated based on the coil surface temperature.

[0006] This application embodiment collects return air temperature and humidity and coil surface temperature, calculates the supercooling capacity, and integrates it to obtain the accumulated frost index. This achieves dual quantification of the instantaneous driving force and accumulated thickness of frost, providing a more reliable physical basis for subsequent decision-making than the traditional single temperature threshold. Secondly, it weights and integrates coil surface temperature, supercooling capacity, accumulated frost index, and external temperature risk to construct a frost risk index, realizing a comprehensive assessment of frost risk and ensuring that the system can accurately identify the defrosting demand window under complex operating conditions. Thirdly, based on the joint judgment of the frost risk index and the coil temperature change rate, and introducing a dynamic duration threshold, it ensures that defrosting is triggered only when the frost risk truly persists. Finally, it matches the defrosting level based on the three core indicators of supercooling capacity, accumulated frost index, and frost risk index, and executes a defrosting operation that matches the intensity. This achieves on-demand and precise defrosting, preventing the efficiency loss caused by insufficient defrosting leading to frost residue and repeated defrosting, and avoiding the ineffective energy consumption and thermal disturbance caused by excessive defrosting, thereby completing defrosting in the shortest time and with the lowest energy consumption. Therefore, this application can solve the problem of low defrosting efficiency in the dehumidification control of cold source fresh air units in the prior art.

[0007] As a preferred example of the first aspect, the step of weighting the coil surface temperature, the supercooling amount, the accumulated frost index, and the preset external temperature risk index according to preset weighting coefficients to obtain a frost risk index for characterizing the overall frost risk includes: The coil frosting indicator parameters are determined based on whether the surface temperature of the coil is lower than the preset freezing point temperature. The supercooling amount is normalized according to the first preset normalization factor to obtain the normalized supercooling amount, and the accumulated frost index is normalized according to the second preset normalization factor to obtain the normalized accumulated frost index. The frost risk index is obtained by multiplying the coil frost indicator parameter, the normalized supercooling capacity, the normalized cumulative frost index, and the external temperature risk index by preset weighting coefficients respectively.

[0008] In this preferred example, the frost indication parameter is determined based on whether the coil surface temperature is below the freezing point, introducing a physical prerequisite of frost for risk calculation and avoiding misjudgment of risk under non-freezing conditions. Secondly, the supercooling amount and cumulative frost index are normalized by a preset normalization factor, eliminating the influence of differences in physical dimensions and orders of magnitude on the weighted calculation, allowing for a reasonable comparison of instantaneous intensity and cumulative effect on the same scale. Finally, the normalized indicators are multiplied by preset weights and summed with the external temperature risk, achieving a comprehensive quantification of multiple factors such as frost drivers, cumulative effects, and ambient coldness. This mechanism ensures that the frost risk index accurately and comprehensively reflects the actual state of coil frost, providing a reliable decision-making basis for subsequent precise graded defrosting, thereby avoiding defrosting efficiency losses due to risk misjudgment.

[0009] As a preferred example of the first aspect, the step of determining whether defrosting is necessary based on the frost risk index and the coil surface temperature change rate includes: When the frost risk index is greater than the preset frost risk threshold and the temperature change rate of the coil surface is less than zero, the duration of the condition being met begins to accumulate, and the duration is taken as the state duration. The dynamic duration threshold is calculated based on the frost risk index, the coil surface temperature change rate, the supercooling amount, and the accumulated frost index. The state duration is then compared with the dynamic duration threshold. If the state duration is greater than or equal to the dynamic duration threshold, it is determined that defrosting is required.

[0010] In this preferred example, the optimal time for defrosting is precisely determined through a mechanism of dual-condition triggering and dynamic threshold comparison. First, timing only begins when the frost risk index exceeds the limit and the coil temperature continues to drop, effectively filtering out interference from instantaneous fluctuations and avoiding false triggering. Second, the duration threshold is dynamically calculated based on the real-time risk status, enabling rapid response under high-risk conditions and delayed triggering under low-risk conditions. This achieves adaptive adjustment of the defrosting timing, ensuring timely intervention before the frost layer deteriorates significantly. This prevents efficiency loss due to delayed defrosting and avoids ineffective energy consumption caused by premature defrosting.

[0011] As a preferred example of the first aspect, the step of matching a corresponding defrost level from a preset defrost grading rule based on the supercooling capacity, the accumulated frost index, and the frost risk index includes... The supercooling amount is compared sequentially with the first preset supercooling threshold, the second preset supercooling threshold, and the third preset supercooling threshold, and the accumulated frost index is compared sequentially with the first preset frost index threshold and the second preset frost index threshold; If the supercooling amount is greater than the first preset supercooling amount threshold and less than the second preset supercooling amount threshold, and the accumulated frost index is less than the first preset frost index threshold, then it is matched as a mild defrosting level. If the supercooling amount is greater than the second preset supercooling amount threshold and less than the third preset supercooling amount threshold, and the accumulated frost index is greater than the first preset frost index threshold and less than the second preset frost index threshold, then it is matched as a medium defrosting level. If the supercooling amount is greater than the third preset supercooling amount threshold and the accumulated frost index is greater than the second preset frost index threshold, then it is matched as a severe defrosting level.

[0012] In this preferred example, precise grading of defrosting intensity is achieved through a joint threshold determination of supercooling and accumulated frost index. Supercooling characterizes the instantaneous driving force of frost formation, while the accumulated frost index characterizes the cumulative thickness of the frost layer. Combined with a multi-level threshold matching mechanism, it can accurately distinguish between light, moderate, and heavy frost states, thereby performing appropriate defrosting operations. This avoids repeated defrosting due to insufficient intensity or energy waste due to excessive intensity, significantly improving defrosting efficiency.

[0013] As a preferred example of the first aspect, the calculation of the ultracooling amount used to characterize the frosting driving force based on the return air temperature, the return air relative humidity, and the coil surface temperature includes: The dew point temperature used to determine whether air condensation has occurred is calculated based on the return air temperature and the return air relative humidity. The ultracooling amount used to characterize the frost-driving force is calculated based on the dew point temperature and the coil surface temperature.

[0014] In this preferred example, the core quantitative indicator of supercooling capacity is constructed by calculating the dew point temperature and comparing it with the coil surface temperature. First, the dew point temperature is accurately calculated based on the return air temperature and humidity, providing an accurate physical benchmark for determining whether the air has condensation conditions. Second, the supercooling capacity is calculated by the difference between the coil surface temperature and the dew point temperature, realizing the direct quantification of the instantaneous driving force of frost formation, providing the most basic original basis for subsequent frost risk assessment and graded defrosting.

[0015] As a preferred example of the first aspect, the calculation of the dew point temperature for determining whether air condensation has occurred based on the return air temperature and the return air relative humidity includes: Intermediate variables are obtained by calculation based on the return air temperature and the return air relative humidity; The dew point temperature used to determine whether air is condensing is obtained by calculating based on the first preset coefficient, the second preset coefficient, and the intermediate variable.

[0016] As a preferred example of the first aspect, the defrosting operation performed on the cold source fresh air unit corresponding to the defrosting level includes: If the matched defrosting level is light defrosting level, the cold source fresh air unit is shut down for a first preset time so that the coil of the cold source fresh air unit defrosts by natural temperature recovery. If the matching defrost level is medium defrost level, the hot gas bypass valve of the cold source fresh air unit is opened, and the high-temperature refrigerant output by the compressor of the cold source fresh air unit is introduced into the coil to heat the surface of the coil for defrosting. If the matched defrost level is heavy defrost, the coil electric heater of the cold source fresh air unit is activated to heat the surface of the coil for defrosting.

[0017] In this preferred example, a matching execution mechanism achieves precise adaptation between defrosting intensity and frost level. Light defrosting employs a short-term shutdown for natural warm-up, eliminating minor frost layers at minimal cost and avoiding unnecessary energy consumption and thermal disturbance. Moderate defrosting activates the hot gas bypass, using high-temperature refrigerant to rapidly heat the coils, achieving a balance between efficiency and energy consumption. Heavy defrosting activates the electric heater, forcefully addressing severe frost conditions to ensure complete frost removal. This tiered execution strategy ensures optimal defrosting effectiveness while achieving optimal energy efficiency across all operating conditions, avoiding repeated defrosting or energy waste caused by inappropriate defrosting intensity.

[0018] Secondly, the present invention provides a dehumidification control device for a cold source fresh air unit, comprising: a data acquisition module, a first control module, a second control module and a third control module; The data acquisition module is used to collect the return air temperature, return air relative humidity and coil surface temperature of the cold source fresh air unit; The first control module is used to calculate the ultracooling amount used to characterize the frost driving force based on the return air temperature, the return air relative humidity and the coil surface temperature, and to determine the cumulative frost index used to characterize the frost accumulation effect based on the ultracooling amount. The second control module is used to perform weighted calculations on the coil surface temperature, the supercooling amount, the accumulated frost index and the preset external temperature risk index according to preset weighting coefficients to obtain a frost risk index that characterizes the overall frost risk. The third control module is used to determine whether defrosting is required based on the frost risk index and the coil surface temperature change rate. If so, it matches the corresponding defrosting level from the preset defrosting classification rules based on the supercooling capacity, the accumulated frost index, and the frost risk index, and performs a defrosting operation corresponding to the defrosting level on the cold source fresh air unit. The coil surface temperature change rate is calculated based on the coil surface temperature.

[0019] As a preferred example of the second aspect, the step of weighting the coil surface temperature, the supercooling amount, the accumulated frost index, and the preset external temperature risk index according to preset weighting coefficients to obtain a frost risk index for characterizing the overall frost risk includes: The coil frosting indicator parameters are determined based on whether the surface temperature of the coil is lower than the preset freezing point temperature. The supercooling amount is normalized according to the first preset normalization factor to obtain the normalized supercooling amount, and the accumulated frost index is normalized according to the second preset normalization factor to obtain the normalized accumulated frost index. The frost risk index is obtained by multiplying the coil frost indicator parameter, the normalized supercooling capacity, the normalized cumulative frost index, and the external temperature risk index by preset weighting coefficients respectively.

[0020] As a preferred example of the second aspect, the step of determining whether defrosting is necessary based on the frost risk index and the coil surface temperature change rate includes: When the frost risk index is greater than the preset frost risk threshold and the temperature change rate of the coil surface is less than zero, the duration of the condition being met begins to accumulate, and the duration is taken as the state duration. The dynamic duration threshold is calculated based on the frost risk index, the coil surface temperature change rate, the supercooling amount, and the accumulated frost index. The state duration is then compared with the dynamic duration threshold. If the state duration is greater than or equal to the dynamic duration threshold, it is determined that defrosting is required.

[0021] As a preferred example of the second aspect, the step of matching a corresponding defrost level from a preset defrost grading rule based on the supercooling amount, the accumulated frost index, and the frost risk index includes: The supercooling amount is compared sequentially with the first preset supercooling threshold, the second preset supercooling threshold, and the third preset supercooling threshold, and the accumulated frost index is compared sequentially with the first preset frost index threshold and the second preset frost index threshold; If the supercooling amount is greater than the first preset supercooling amount threshold and less than the second preset supercooling amount threshold, and the accumulated frost index is less than the first preset frost index threshold, then it is matched as a mild defrosting level. If the supercooling amount is greater than the second preset supercooling amount threshold and less than the third preset supercooling amount threshold, and the accumulated frost index is greater than the first preset frost index threshold and less than the second preset frost index threshold, then it is matched as a medium defrosting level. If the supercooling amount is greater than the third preset supercooling amount threshold and the accumulated frost index is greater than the second preset frost index threshold, then it is matched as a severe defrosting level.

[0022] As a preferred example of the second aspect, the calculation of the ultracooling amount used to characterize the frosting driving force based on the return air temperature, the return air relative humidity, and the coil surface temperature includes: The dew point temperature used to determine whether air condensation has occurred is calculated based on the return air temperature and the return air relative humidity. The ultracooling amount used to characterize the frost-driving force is calculated based on the dew point temperature and the coil surface temperature.

[0023] As a preferred example of the second aspect, the calculation of the dew point temperature for determining whether condensation has occurred based on the return air temperature and the return air relative humidity includes: Intermediate variables are obtained by calculation based on the return air temperature and the return air relative humidity; The dew point temperature used to determine whether air is condensing is obtained by calculating based on the first preset coefficient, the second preset coefficient, and the intermediate variable.

[0024] As a preferred example of the second aspect, the defrosting operation performed on the cold source fresh air unit corresponding to the defrosting level includes: If the matched defrosting level is light defrosting level, the cold source fresh air unit is shut down for a first preset time so that the coil of the cold source fresh air unit defrosts by natural temperature recovery. If the matching defrost level is medium defrost level, the hot gas bypass valve of the cold source fresh air unit is opened, and the high-temperature refrigerant output by the compressor of the cold source fresh air unit is introduced into the coil to heat the surface of the coil for defrosting. If the matched defrost level is heavy defrost, the coil electric heater of the cold source fresh air unit is activated to heat the surface of the coil for defrosting.

[0025] In summary, this embodiment of the application collects return air temperature and humidity and coil surface temperature, calculates the supercooling capacity, and integrates it to obtain the accumulated frost index, achieving dual quantification of the instantaneous driving force and accumulated thickness of frost formation. This provides a more reliable physical basis for subsequent decision-making than the traditional single temperature threshold. Secondly, by weighting and integrating coil surface temperature, supercooling capacity, accumulated frost index, and external temperature risk, a frost risk index is constructed, enabling a comprehensive assessment of frost risk and ensuring that the system can accurately identify defrosting demand windows under complex operating conditions. Thirdly, based on the joint judgment of the frost risk index and the coil temperature change rate, and by introducing a dynamic duration threshold, defrosting is only triggered when the frost risk truly persists. Finally, based on the three core indicators of supercooling capacity, accumulated frost index, and frost risk index, the defrosting level is matched, and a defrosting operation matching the intensity is executed. This achieves on-demand and precise defrosting, preventing the efficiency loss caused by insufficient defrosting leading to frost residue and repeated defrosting, while avoiding the ineffective energy consumption and thermal disturbance caused by excessive defrosting. Thus, defrosting is completed in the shortest time and with the lowest energy consumption. Therefore, this application can solve the problem of low defrosting efficiency in the dehumidification control of cold source fresh air units in the prior art.

[0026] Another embodiment of the present invention provides a terminal device, including: a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the steps of the dehumidification control method of the cold source fresh air unit of the present invention.

[0027] Another embodiment of the present invention provides a computer-readable storage medium item, including: a stored computer program, which, when the computer program is running, controls the device where the computer-readable storage medium is located to perform the steps of the dehumidification control method of the cold source fresh air unit of the present invention. Attached Figure Description

[0028] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a schematic flowchart of an embodiment of a dehumidification control method for a cold source fresh air unit provided by the present invention; Figure 2 This is a module structure diagram of one embodiment of a dehumidification control device for a cold source fresh air unit provided by the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0032] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0033] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0034] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0035] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0036] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0037] Example 1 See Figure 1 To address the problem of low defrosting efficiency in the dehumidification control of existing cold source fresh air handling units, an embodiment of the present invention provides a dehumidification control method for cold source fresh air handling units, comprising: S1. Collect the return air temperature, return air relative humidity, and coil surface temperature of the cold source fresh air unit; Specifically, the return air temperature can be measured by a return air humidity sensor, the return air relative humidity can be measured by a return air temperature sensor, and the coil surface temperature can be measured by a coil temperature sensor.

[0038] S2. Calculate the ultracooling amount used to characterize the frost driving force based on the return air temperature, the return air relative humidity and the coil surface temperature, and determine the cumulative frost index used to characterize the frost accumulation effect based on the ultracooling amount. In a preferred embodiment, the calculation of the ultracooling amount used to characterize the frosting driving force based on the return air temperature, the return air relative humidity, and the coil surface temperature includes: The dew point temperature used to determine whether air condensation has occurred is calculated based on the return air temperature and the return air relative humidity. The ultracooling amount used to characterize the frost-driving force is calculated based on the dew point temperature and the coil surface temperature.

[0039] In a preferred embodiment, the step of calculating the dew point temperature for determining whether condensation has occurred based on the return air temperature and the return air relative humidity includes: Intermediate variables are obtained by calculation based on the return air temperature and the return air relative humidity; The dew point temperature used to determine whether air is condensing is obtained by calculating based on the first preset coefficient, the second preset coefficient, and the intermediate variable.

[0040] It should be noted that in the dehumidification control of a chilled air handling unit, effective dehumidification is achieved by adjusting the coil surface temperature and airflow to keep the dew point temperature of the supply air below the set value. However, when the unit operates under low external temperature or low load conditions, the coil surface temperature may drop below the dew point, causing condensate to frost. Once frost forms, the heat exchange efficiency of the coil decreases significantly, and the temperature and humidity regulation capability of the air passing through the coil is limited, thus weakening the dehumidification effect. Continuous frost may also cause abnormal compression cycle or damage to the equipment. The dew point temperature is the temperature at which water vapor in the air reaches saturation. If the coil surface temperature is lower than the dew point temperature, condensation will inevitably occur; if the coil surface temperature is much lower than the dew point temperature, the condensation amount is large and the freezing speed is fast, which is the basic signal for all frost judgment and classification.

[0041] Specifically, the dew point temperature used to determine whether condensation has occurred is calculated based on the return air temperature and the return air relative humidity. This calculation can be performed using the Magnus formula, as shown below: in, This represents an intermediate variable in the Magnus formula, used to combine air humidity and dry-bulb temperature to facilitate subsequent calculation of dew point temperature. Indicates the relative humidity of the return air. It is 17.27. 237.7 ( , All of these are parameters of the Magnus formula, which are empirical constants. This indicates the return air temperature, which is the dry-bulb temperature of the air before it enters the coil. The dew point temperature is the temperature at which water vapor in the air begins to condense. Generally speaking, if the surface temperature of the coil is lower than the dew point temperature, the air will begin to condense, and if it is much lower, it is usually easy for frost to form.

[0042] It should be noted that the greater the supercooling capacity, the lower the coil surface temperature is compared to the dew point temperature, and the greater the condensation, the higher the risk of frosting.

[0043] Specifically, the supercooling amount used to characterize the frost-generating driving force is calculated based on the dew point temperature and the coil surface temperature, and the specific formula is as follows: in, Indicates supercooling capacity. This indicates the surface temperature of the coil.

[0044] Furthermore, the calculation of dew point temperature directly depends on the accuracy of the temperature and humidity sensors, so error sources such as humidity drift, temperature hysteresis, and sampling lag should be considered. At the same time, dew point temperature changes are volatile, and instantaneous jumps can occur when airflow or return air humidity load changes. Therefore, it is necessary to filter the sensor data, for example, using moving averages, which will not be elaborated here.

[0045] Specifically, the cumulative frost index, which characterizes the frost accumulation effect based on the supercooling amount, can be calculated using the following formula: in, The cumulative frost index, expressed in °C·min or °C·s (depending on the time unit), describes the cumulative amount by which the coil surface temperature falls below the dew point temperature within a past window. Indicates the current time. Indicates the length of the integration window, describing the time range for subsequent accumulation. Represents the integral variable. , Indicates at time The return air dew point temperature, Indicates at time Coil surface temperature, This indicates the operation of obtaining a non-negative value, which only occurs when... Accumulation is only counted when there is condensation potential.

[0046] It should be noted that supercooling only reflects the condensation potential at the moment, but frosting is usually a process with a cumulative effect over time: a short-term, small amount of supercooling may not cause frost to form immediately, but if this supercooling continues, it will lead to condensation accumulation and eventually form a frost layer. The cumulative frost index quantifies the magnitude by multiplying it by time, which can identify persistent risks in advance, filter out instantaneous noise, and provide a quantitative basis for classification, thereby improving the accuracy and energy efficiency of defrosting strategies.

[0047] S3. The surface temperature of the coil, the supercooling amount, the accumulated frost index and the preset external temperature risk index are weighted according to the preset weighting coefficient to obtain the frost risk index used to characterize the comprehensive frost risk. In a preferred embodiment, the step of weighting the coil surface temperature, the supercooling amount, the accumulated frost index, and the preset external temperature risk index according to preset weighting coefficients to obtain a frost risk index for characterizing the overall frost risk includes: The coil frosting indicator parameters are determined based on whether the surface temperature of the coil is lower than the preset freezing point temperature. The supercooling amount is normalized according to the first preset normalization factor to obtain the normalized supercooling amount, and the accumulated frost index is normalized according to the second preset normalization factor to obtain the normalized accumulated frost index. The frost risk index is obtained by multiplying the coil frost indicator parameter, the normalized supercooling capacity, the normalized cumulative frost index, and the external temperature risk index by preset weighting coefficients respectively.

[0048] Specifically, the coil surface temperature, the supercooling amount, the accumulated frost index, and the preset external temperature risk index are weighted according to preset weighting coefficients to obtain a frost risk index that characterizes the overall frost risk. This index can be calculated using the following formula: in, This represents a frost risk index, quantifying the current risk level of frost buildup on the coils, and is used for subsequent frost prevention strategy decisions. This indicates the function for indicating coil frost formation, when... Select 1, otherwise select 0 (0 here is used to describe the freezing point temperature of water. The surface temperature of the coil is lower than the dew point temperature of the return air so that water vapor in the air will condense into liquid water on the surface of the coil; the surface temperature of the coil must be lower than 0°C so that the precipitated liquid water can freeze quickly into ice crystals, i.e. frost, instead of existing in the form of liquid water). This represents the supercooling normalization factor, used to convert temperature differences into comparable dimensions, such as the 0-1 range. This represents the calibration reference value, used for normalizing the accumulated frost index. This indicates external temperature risk, describing how external or forecast temperatures are mapped to a dimensionless index related to frost risk; the lower the external temperature, the higher the risk. , , and These are the corresponding weight coefficients, and the sum of the four is 1, which are preset values.

[0049] Among them, external temperature risk Based on linear mapping, the specific formula is as follows: in, The external temperature is typically measured by an outdoor temperature sensor installed outside the chilled air handling unit. This sensor accurately reflects the outdoor atmospheric temperature and should be protected from direct sunlight and other heat sources. It describes the climatic conditions of the environment in which the unit operates. and These represent the high temperature threshold and the low temperature threshold, respectively. Exceeding the high temperature threshold minimizes the risk, while falling below the low temperature threshold maximizes the risk.

[0050] The defrost trigger condition is then established as follows: in, Indicates the frost risk threshold, at If the risk is sufficiently high, defrosting may need to be considered. This indicates the rate of change of the coil surface temperature, reflecting the judgment of whether the coil temperature is continuously decreasing and avoiding false triggering. Indicates duration, This indicates the duration threshold. It should be noted that the duration... This refers to the condition " "and" "The accumulated time at the time of establishment. When the above three conditions are met, the defrosting control command of the cold source fresh air unit is triggered."

[0051] It is worth noting that the method for determining the minimum time threshold is as follows: in, This represents a status indicator, ranging from 0 to 1, used to dynamically determine the duration threshold for defrosting triggering. A higher value indicates a higher risk state for the system. This indicates the maximum value of the frost risk index. This indicates the maximum rate of change of temperature on the coil surface. This indicates the maximum value of the supercooling capacity. This indicates the maximum accumulated frost index. , , and These are the corresponding weight coefficients; Next, the state indicators are mapped to duration thresholds, using the following formula: in, and These represent the minimum and maximum allowed durations and the empirical preset values, respectively.

[0052] S4. Based on the frost risk index and the coil surface temperature change rate, determine whether defrosting is required. If so, match the corresponding defrosting level from the preset defrosting classification rules based on the supercooling capacity, the accumulated frost index, and the frost risk index, and perform a defrosting operation corresponding to the defrosting level on the cold source fresh air unit; wherein, the coil surface temperature change rate is calculated based on the coil surface temperature.

[0053] As a preferred embodiment, determining whether defrosting is necessary based on the frost risk index and the coil surface temperature change rate includes: When the frost risk index is greater than the preset frost risk threshold and the temperature change rate of the coil surface is less than zero, the duration of the condition being met begins to accumulate, and the duration is taken as the state duration. The dynamic duration threshold is calculated based on the frost risk index, the coil surface temperature change rate, the supercooling amount, and the accumulated frost index. The state duration is then compared with the dynamic duration threshold. If the state duration is greater than or equal to the dynamic duration threshold, it is determined that defrosting is required.

[0054] As a preferred embodiment, the step of matching a corresponding defrost level from a preset defrost grading rule based on the supercooling amount, the accumulated frost index, and the frost risk index includes: The supercooling amount is compared sequentially with the first preset supercooling threshold, the second preset supercooling threshold, and the third preset supercooling threshold, and the accumulated frost index is compared sequentially with the first preset frost index threshold and the second preset frost index threshold; If the supercooling amount is greater than the first preset supercooling amount threshold and less than the second preset supercooling amount threshold, and the accumulated frost index is less than the first preset frost index threshold, then it is matched as a mild defrosting level. If the supercooling amount is greater than the second preset supercooling amount threshold and less than the third preset supercooling amount threshold, and the accumulated frost index is greater than the first preset frost index threshold and less than the second preset frost index threshold, then it is matched as a medium defrosting level. If the supercooling amount is greater than the third preset supercooling amount threshold and the accumulated frost index is greater than the second preset frost index threshold, then it is matched as a severe defrosting level.

[0055] In a preferred embodiment, performing a defrosting operation on the cold source fresh air handling unit corresponding to the defrosting level includes: If the matched defrosting level is light defrosting level, the cold source fresh air unit is shut down for a first preset time so that the coil of the cold source fresh air unit defrosts by natural temperature recovery. If the matching defrost level is medium defrost level, the hot gas bypass valve of the cold source fresh air unit is opened, and the high-temperature refrigerant output by the compressor of the cold source fresh air unit is introduced into the coil to heat the surface of the coil for defrosting. If the matched defrost level is heavy defrost, the coil electric heater of the cold source fresh air unit is activated to heat the surface of the coil for defrosting.

[0056] In summary, this embodiment of the application collects return air temperature and humidity and coil surface temperature, calculates the supercooling capacity, and integrates it to obtain the accumulated frost index, achieving dual quantification of the instantaneous driving force and accumulated thickness of frost formation. This provides a more reliable physical basis for subsequent decision-making than the traditional single temperature threshold. Secondly, by weighting and integrating coil surface temperature, supercooling capacity, accumulated frost index, and external temperature risk, a frost risk index is constructed, enabling a comprehensive assessment of frost risk and ensuring that the system can accurately identify defrosting demand windows under complex operating conditions. Thirdly, based on the joint judgment of the frost risk index and the coil temperature change rate, and by introducing a dynamic duration threshold, defrosting is only triggered when the frost risk truly persists. Finally, based on the three core indicators of supercooling capacity, accumulated frost index, and frost risk index, the defrosting level is matched, and a defrosting operation matching the intensity is executed. This achieves on-demand and precise defrosting, preventing the efficiency loss caused by insufficient defrosting leading to frost residue and repeated defrosting, while avoiding the ineffective energy consumption and thermal disturbance caused by excessive defrosting. Thus, defrosting is completed in the shortest time and with the lowest energy consumption. Therefore, this application can solve the problem of low defrosting efficiency in the dehumidification control of cold source fresh air units in the prior art.

[0057] In addition, if none of the above-mentioned mild, moderate, or severe defrosting conditions are triggered, it may indicate that the current frost risk is low and defrosting is not necessary. However, the future frost risk index is unknown. Furthermore, predicting the future frost risk index indicates the future frost risk of the cold source fresh air handling unit: The frost risk prediction module is used to obtain the calculated frost risk index as the autoregressive part, while the accumulated frost index, coil surface temperature, dew point temperature, supercooling amount and external temperature risk are used as the input exogenous variables. Based on the aforementioned autoregressive and exogenous variable components, an autoregressive-exogenous variable model (ARX) is constructed to predict the frost risk index. In the formula: The frost risk index represents the predicted future time. Indicates the prediction step size, describing the future time interval. This represents the frost risk index for the current and past i steps (when using it, instantaneous noise or sensor error can be removed by using a moving average or low-pass filtering, and the same applies to subsequent values). This indicates the order of the autoregression, i.e., how many steps in the past are considered. , This represents the corresponding regression coefficient. This represents the accumulated frost index over the current and past j steps. Indicates the lag order. This represents the corresponding regression coefficient. This indicates the current and past supercooling capacity of the coil in steps m. Represents the regression coefficient. The regression coefficient representing the risk of external temperature. This represents random disturbances, describing prediction error. It is typically assumed to have a mean of 0. i, j, and m represent the lag step size, used to describe historical data viewed from the current time point. , , These represent the past index positions obtained by subtracting the lag steps from the time index; the regression coefficients are solved using the least squares method. Specifically, existing technologies and numerous public documents explicitly state that the coefficients are solved using the least squares method or recursive least squares method, so this embodiment will not elaborate further. Secondly, each term in the autoregressive exogenous variable model is an eigenvalue multiplied by the corresponding regression coefficient. The regression coefficient itself adjusts the units; different input units will result in different regression coefficients. The units and units of the regression coefficients are automatically aligned to the units of the output quantity. This is common and well-known in autoregressive exogenous variable models, and therefore will not be elaborated further.

[0058] It should be noted that the prediction of the frost risk index is based on its significant time correlation. That is, the current frost risk index is closely related to the frost conditions at certain points in the past. At the same time, the frosting process of the air cooler coil depends on the historical coil surface temperature, supercooling amount, and accumulated frost index. These quantities reflect the delayed characteristics of frost formation through time integration or weighted averaging. Therefore, the past frost risk index can provide effective information for short-term trend prediction.

[0059] Furthermore, external environmental factors can directly impact frost risk; for example, changes in air temperature and humidity alter condensation and frosting conditions. External temperature risk serves as input, providing environmental disturbance information to the prediction model and thus improving prediction accuracy. Based on this temporal correlation and external causality, an autoregressive model with exogenous parameters is employed to combine the frost risk index, accumulated frost index, coil supercooling, and external temperature risk value to achieve short-term predictions of future frost risk. This leverages the lag characteristics of physical processes while ensuring prediction accuracy.

[0060] Therefore, the frost risk index for future moments is output to management personnel to assess the risks in the future. This allows for advance planning of defrosting control when the frost risk index is high in the future, improving the ability to make advance decisions in task execution and reducing the high energy consumption and frequent defrosting that may result from delays.

[0061] Example 2 like Figure 2 As shown, based on the above method embodiments, corresponding device embodiments are provided; An embodiment of the present invention provides a dehumidification control device for a cold source fresh air unit, comprising: a data acquisition module 21, a first control module 22, a second control module 23, and a third control module 24; Data acquisition module 21 is used to acquire the return air temperature, return air relative humidity and coil surface temperature of the cold source fresh air unit; The first control module 22 is used to calculate the ultracooling amount used to characterize the frost driving force based on the return air temperature, the return air relative humidity and the coil surface temperature, and to determine the cumulative frost index used to characterize the frost accumulation effect based on the ultracooling amount. The second control module 23 is used to perform weighted calculations on the coil surface temperature, the supercooling amount, the accumulated frost index and the preset external temperature risk index according to preset weighting coefficients to obtain a frost risk index used to characterize the overall frost risk. The third control module 24 is used to determine whether defrosting is required based on the frost risk index and the coil surface temperature change rate. If so, it matches the corresponding defrosting level from the preset defrosting classification rules based on the supercooling capacity, the accumulated frost index and the frost risk index, and performs a defrosting operation corresponding to the defrosting level on the cold source fresh air unit. The coil surface temperature change rate is calculated based on the coil surface temperature.

[0062] In a preferred embodiment, the step of weighting the coil surface temperature, the supercooling amount, the accumulated frost index, and the preset external temperature risk index according to preset weighting coefficients to obtain a frost risk index for characterizing the overall frost risk includes: The coil frosting indicator parameters are determined based on whether the surface temperature of the coil is lower than the preset freezing point temperature. The supercooling amount is normalized according to the first preset normalization factor to obtain the normalized supercooling amount, and the accumulated frost index is normalized according to the second preset normalization factor to obtain the normalized accumulated frost index. The frost risk index is obtained by multiplying the coil frost indicator parameter, the normalized supercooling capacity, the normalized cumulative frost index, and the external temperature risk index by preset weighting coefficients respectively.

[0063] As a preferred embodiment, determining whether defrosting is necessary based on the frost risk index and the coil surface temperature change rate includes: When the frost risk index is greater than the preset frost risk threshold and the temperature change rate of the coil surface is less than zero, the duration of the condition being met begins to accumulate, and the duration is taken as the state duration. The dynamic duration threshold is calculated based on the frost risk index, the coil surface temperature change rate, the supercooling amount, and the accumulated frost index. The state duration is then compared with the dynamic duration threshold. If the state duration is greater than or equal to the dynamic duration threshold, it is determined that defrosting is required.

[0064] As a preferred embodiment, the step of matching a corresponding defrost level from a preset defrost grading rule based on the supercooling amount, the accumulated frost index, and the frost risk index includes: The supercooling amount is compared sequentially with the first preset supercooling threshold, the second preset supercooling threshold, and the third preset supercooling threshold, and the accumulated frost index is compared sequentially with the first preset frost index threshold and the second preset frost index threshold; If the supercooling amount is greater than the first preset supercooling amount threshold and less than the second preset supercooling amount threshold, and the accumulated frost index is less than the first preset frost index threshold, then it is matched as a mild defrosting level. If the supercooling amount is greater than the second preset supercooling amount threshold and less than the third preset supercooling amount threshold, and the accumulated frost index is greater than the first preset frost index threshold and less than the second preset frost index threshold, then it is matched as a medium defrosting level. If the supercooling amount is greater than the third preset supercooling amount threshold and the accumulated frost index is greater than the second preset frost index threshold, then it is matched as a severe defrosting level.

[0065] In a preferred embodiment, the calculation of the ultracooling amount used to characterize the frosting driving force based on the return air temperature, the return air relative humidity, and the coil surface temperature includes: The dew point temperature used to determine whether air condensation has occurred is calculated based on the return air temperature and the return air relative humidity. The ultracooling amount used to characterize the frost-driving force is calculated based on the dew point temperature and the coil surface temperature.

[0066] In a preferred embodiment, the step of calculating the dew point temperature for determining whether condensation has occurred based on the return air temperature and the return air relative humidity includes: Intermediate variables are obtained by calculation based on the return air temperature and the return air relative humidity; The dew point temperature used to determine whether air is condensing is obtained by calculating based on the first preset coefficient, the second preset coefficient, and the intermediate variable.

[0067] In a preferred embodiment, performing a defrosting operation on the cold source fresh air handling unit corresponding to the defrosting level includes: If the matched defrosting level is light defrosting level, the cold source fresh air unit is shut down for a first preset time so that the coil of the cold source fresh air unit defrosts by natural temperature recovery. If the matching defrost level is medium defrost level, the hot gas bypass valve of the cold source fresh air unit is opened, and the high-temperature refrigerant output by the compressor of the cold source fresh air unit is introduced into the coil to heat the surface of the coil for defrosting. If the matched defrost level is heavy defrost, the coil electric heater of the cold source fresh air unit is activated to heat the surface of the coil for defrosting.

[0068] For more detailed steps and working principles of this embodiment, please refer to the relevant description in Embodiment 1, but not limited to these descriptions.

[0069] In summary, this embodiment of the application collects return air temperature and humidity and coil surface temperature, calculates the supercooling capacity, and integrates it to obtain the accumulated frost index, achieving dual quantification of the instantaneous driving force and accumulated thickness of frost formation. This provides a more reliable physical basis for subsequent decision-making than the traditional single temperature threshold. Secondly, by weighting and integrating coil surface temperature, supercooling capacity, accumulated frost index, and external temperature risk, a frost risk index is constructed, enabling a comprehensive assessment of frost risk and ensuring that the system can accurately identify defrosting demand windows under complex operating conditions. Thirdly, based on the joint judgment of the frost risk index and the coil temperature change rate, and by introducing a dynamic duration threshold, defrosting is only triggered when the frost risk truly persists. Finally, based on the three core indicators of supercooling capacity, accumulated frost index, and frost risk index, the defrosting level is matched, and a defrosting operation matching the intensity is executed. This achieves on-demand and precise defrosting, preventing the efficiency loss caused by insufficient defrosting leading to frost residue and repeated defrosting, while avoiding the ineffective energy consumption and thermal disturbance caused by excessive defrosting. Thus, defrosting is completed in the shortest time and with the lowest energy consumption. Therefore, this application can solve the problem of low defrosting efficiency in the dehumidification control of cold source fresh air units in the prior art.

[0070] It is understood that the above-described device embodiments correspond to the method embodiments of the present invention, and can implement the dehumidification control method for cold source fresh air units provided by any of the above-described method embodiments of the present invention.

[0071] It should be noted that the device embodiments described above are merely illustrative, and some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the accompanying drawings of the device embodiments provided by this invention, the connection relationships between modules indicate that they have communication connections, which can specifically be implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement this without any creative effort.

[0072] Example 3 Based on the above embodiments of the dehumidification control method for cold source fresh air handling units, another embodiment of the present invention provides a terminal device, which includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the dehumidification control method for cold source fresh air handling units according to any embodiment of the present invention.

[0073] For example, in this embodiment, the computer program can be divided into one or more modules, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program in the terminal device.

[0074] The terminal device may be a desktop computer, laptop, handheld computer, or cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0075] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the terminal device, connecting all parts of the terminal device via various interfaces and lines.

[0076] Example 4 Based on the above-described method embodiments, another embodiment of the present invention provides a computer-readable storage medium including a stored computer program, wherein, when the computer program is executed, it controls the device where the computer-readable storage medium is located to execute the dehumidification control method of the cold source fresh air unit described in any of the above-described method embodiments of the present invention.

[0077] The modules / units integrated in the device / terminal equipment, if implemented as software functional units and sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0078] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A dehumidification control method for a cold source fresh air handling unit, characterized in that, include: The return air temperature, return air relative humidity, and coil surface temperature of the cold source fresh air unit were collected. The ultracooling amount used to characterize the frost driving force is calculated based on the return air temperature, the return air relative humidity and the coil surface temperature, and the cumulative frost index used to characterize the frost accumulation effect is determined based on the ultracooling amount. The coil surface temperature, the supercooling amount, the accumulated frost index, and the preset external temperature risk index are weighted according to preset weighting coefficients to obtain a frost risk index used to characterize the overall frost risk. Based on the frost risk index and the coil surface temperature change rate, it is determined whether defrosting is required. If so, based on the supercooling capacity, the accumulated frost index, and the frost risk index, the corresponding defrosting level is matched from the preset defrosting classification rules, and the defrosting operation corresponding to the defrosting level is performed on the cold source fresh air unit; wherein, the coil surface temperature change rate is calculated based on the coil surface temperature.

2. The dehumidification control method for a cold source fresh air handling unit as described in claim 1, characterized in that, The step involves weighting the coil surface temperature, the supercooling amount, the accumulated frost index, and the preset external temperature risk index according to preset weighting coefficients to obtain a frost risk index characterizing the overall frost risk, including: The coil frosting indicator parameters are determined based on whether the surface temperature of the coil is lower than the preset freezing point temperature. The supercooling amount is normalized according to the first preset normalization factor to obtain the normalized supercooling amount, and the accumulated frost index is normalized according to the second preset normalization factor to obtain the normalized accumulated frost index. The frost risk index is obtained by multiplying the coil frost indicator parameter, the normalized supercooling capacity, the normalized cumulative frost index, and the external temperature risk index by preset weighting coefficients respectively.

3. The dehumidification control method for a cold source fresh air handling unit as described in claim 1, characterized in that, The step of determining whether defrosting is necessary based on the frost risk index and the coil surface temperature change rate includes: When the frost risk index is greater than the preset frost risk threshold and the temperature change rate of the coil surface is less than zero, the duration of the condition being met begins to accumulate, and the duration is taken as the state duration. The dynamic duration threshold is calculated based on the frost risk index, the coil surface temperature change rate, the supercooling amount, and the accumulated frost index. The state duration is then compared with the dynamic duration threshold. If the state duration is greater than or equal to the dynamic duration threshold, it is determined that defrosting is required.

4. The dehumidification control method for a cold source fresh air handling unit as described in claim 1, characterized in that, The step of matching a corresponding defrost level from a preset defrost grading rule based on the supercooling amount, the accumulated frost index, and the frost risk index includes: The supercooling amount is compared sequentially with the first preset supercooling threshold, the second preset supercooling threshold, and the third preset supercooling threshold, and the accumulated frost index is compared sequentially with the first preset frost index threshold and the second preset frost index threshold. If the supercooling amount is greater than the first preset supercooling amount threshold and less than the second preset supercooling amount threshold, and the accumulated frost index is less than the first preset frost index threshold, then it is matched as a light defrosting level. If the supercooling amount is greater than the second preset supercooling amount threshold and less than the third preset supercooling amount threshold, and the accumulated frost index is greater than the first preset frost index threshold and less than the second preset frost index threshold, then it is matched as a medium defrosting level. If the supercooling amount is greater than the third preset supercooling amount threshold and the accumulated frost index is greater than the second preset frost index threshold, then it is matched as a severe defrosting level.

5. The dehumidification control method for a cold source fresh air handling unit as described in claim 1, characterized in that, The calculation based on the return air temperature, the return air relative humidity, and the coil surface temperature yields the ultracooling amount used to characterize the frosting driving force, including: The dew point temperature used to determine whether air condensation has occurred is calculated based on the return air temperature and the return air relative humidity. The ultracooling amount used to characterize the frost-driving force is calculated based on the dew point temperature and the coil surface temperature.

6. The dehumidification control method for a cold source fresh air handling unit as described in claim 5, characterized in that, The step of calculating the dew point temperature for determining whether condensation has occurred based on the return air temperature and the return air relative humidity includes: Intermediate variables are obtained by calculation based on the return air temperature and the return air relative humidity; The dew point temperature used to determine whether air is condensing is obtained by calculating based on the first preset coefficient, the second preset coefficient, and the intermediate variable.

7. The dehumidification control method for a cold source fresh air handling unit as described in claim 4, characterized in that, The defrosting operation performed on the cold source fresh air unit corresponding to the defrosting level includes: If the matched defrosting level is light defrosting level, the cold source fresh air unit is shut down for a first preset time so that the coil of the cold source fresh air unit defrosts by natural temperature recovery. If the matching defrost level is medium defrost level, the hot gas bypass valve of the cold source fresh air unit is opened, and the high-temperature refrigerant output by the compressor of the cold source fresh air unit is introduced into the coil to heat the surface of the coil for defrosting. If the matched defrost level is heavy defrost, the coil electric heater of the cold source fresh air unit is activated to heat the surface of the coil for defrosting.

8. A dehumidification control device for a cold source fresh air handling unit, characterized in that, include: The system comprises a data acquisition module, a first control module, a second control module, and a third control module. The data acquisition module is used to collect the return air temperature, return air relative humidity and coil surface temperature of the cold source fresh air unit; The first control module is used to calculate the ultracooling amount used to characterize the frost driving force based on the return air temperature, the return air relative humidity and the coil surface temperature, and to determine the cumulative frost index used to characterize the frost accumulation effect based on the ultracooling amount. The second control module is used to perform weighted calculations on the coil surface temperature, the supercooling amount, the accumulated frost index and the preset external temperature risk index according to preset weighting coefficients to obtain a frost risk index that characterizes the overall frost risk. The third control module is used to determine whether defrosting is required based on the frost risk index and the coil surface temperature change rate. If so, it matches the corresponding defrosting level from the preset defrosting classification rules based on the supercooling capacity, the accumulated frost index, and the frost risk index, and performs a defrosting operation corresponding to the defrosting level on the cold source fresh air unit. The coil surface temperature change rate is calculated based on the coil surface temperature.

9. A terminal device, characterized in that, The system includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein when the processor executes the computer program, it implements the dehumidification control method for a cold source fresh air unit as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, include: A stored computer program, wherein, when the computer program is executed, it controls the device containing the computer-readable storage medium to perform the dehumidification control method for a cold source fresh air handling unit as described in any one of claims 1-7.

Images