Carbon dioxide heat pump defrosting control method, device, equipment, storage medium and product

Abstract

The invention provides a carbon dioxide heat pump defrosting control method, device and equipment, a storage medium and a product. The method comprises the steps that the environment temperature of the environment where the heat pump is located and the relative humidity of air of the environment where the heat pump is located are obtained; calculating a corresponding dew point temperature according to the environment temperature and the relative humidity; fuzzy reasoning is conducted on the basis of the environment temperature, the relative humidity and the dew point temperature, and a fuzzy set of the defrosting demand degree of the heat pump is obtained; solving the fuzzy set to obtain a defrosting demand degree accurate value; and under the condition that the defrosting demand degree accurate value is larger than a first preset threshold value, the evaporator is defrosted based on the difference value between the heat currently absorbed by the evaporator in the heat pump and the reference heat and the difference value between the current power of a draught fan in the heat pump and the reference power. Therefore, unnecessary defrosting energy consumption is reduced while the heat exchange efficiency is guaranteed, and the accuracy of judgment on defrosting of the evaporator is improved.

Description

Technical Field

[0001] This application relates to the field of heat pump control technology, and in particular to a method, apparatus, equipment, storage medium and product for defrosting control of a carbon dioxide heat pump. Background Technology

[0002] When air source heat pumps operate in low-temperature and high-humidity environments, frost easily forms on the evaporator surface, leading to decreased heat exchange efficiency, increased energy consumption, and severely impacting the system's heating performance and operational reliability. This is especially true for heat pump systems using transcritical carbon dioxide cycles, which, due to their high operating pressure, high evaporation temperature, and large fluctuations in operating conditions, are prone to false defrosting predictions, frequent start-ups and shutdowns, or delayed defrosting. The impact of frosting and defrosting processes on system stability is even more pronounced, further reducing system energy efficiency and lifespan.

[0003] Current defrosting control methods rely on indirect or single judgment indicators, lacking a direct response to the physical critical conditions for frost formation. This leads to frequent misjudgments of defrosting timing in actual operation, potentially initiating defrosting unnecessarily, resulting in energy waste, or failing to defrost in time when the frost layer has severely impacted performance. The accuracy and adaptability of defrosting judgments in existing technologies are insufficient, causing frequent system start-ups and shutdowns and decreased energy efficiency. Summary of the Invention

[0004] This application provides a carbon dioxide heat pump defrosting control method, apparatus, equipment, storage medium, and product, aiming to solve the technical problem of insufficient accuracy in defrosting judgment in related technologies.

[0005] In a first aspect, this application provides a method for controlling defrosting of a carbon dioxide heat pump, the method comprising: The ambient temperature and relative humidity of the air in the environment where the heat pump is located are obtained. Calculate the corresponding dew point temperature based on the ambient temperature and relative humidity; Based on the ambient temperature, relative humidity and dew point temperature, fuzzy inference is performed to obtain the fuzzy set of the defrosting demand of the heat pump; Solve the fuzzy set to obtain the precise value of defrosting demand; If the defrosting demand accuracy value is greater than a first preset threshold, the evaporator is defrosted based on the difference between the heat currently absorbed by the evaporator in the heat pump and the reference heat, and the difference between the current power of the fan in the heat pump and the reference power.

[0006] In some possible implementations, when the defrosting demand precision value is greater than the first preset threshold, defrosting the evaporator based on the difference between the heat currently absorbed by the evaporator in the heat pump and the reference heat, and the difference between the current power of the fan in the heat pump and the reference power, includes: If the defrosting demand accuracy value is greater than the first preset threshold, the heat currently absorbed by the evaporator and the current power of the fan in the heat pump are calculated based on the current state of the evaporator and the current state of the fan, respectively. The evaporator is defrosted when the heat level decreases by a first preset value compared to the reference heat level, or when the current power increases by a second preset value compared to the reference power level.

[0007] In some possible implementations, calculating the current heat absorbed by the evaporator and the current power of the fan in the heat pump based on the current states of the evaporator and the fan, respectively, includes: Calculate the heat absorbed by the evaporator in the heat pump based on the current refrigerant state at the inlet and outlet of the evaporator. Calculate the current power of the fan in the heat pump based on the current input voltage and current of the fan.

[0008] In some possible implementations, calculating the heat currently absorbed by the evaporator in the heat pump based on the current refrigerant state at the inlet and outlet of the evaporator includes: The first specific enthalpy of the refrigerant at the inlet is obtained based on the current refrigerant temperature and specific heat capacity at the inlet of the evaporator in the heat pump. Based on the current refrigerant temperature and specific heat capacity at the outlet of the evaporator in the heat pump, the second specific enthalpy of the refrigerant at the outlet is obtained. The heat absorbed by the evaporator is calculated based on the difference between the first and second specific enthalpy and the current refrigerant flow rate of the evaporator.

[0009] In some possible implementations, calculating the corresponding dew point temperature based on the ambient temperature and the relative humidity includes: Based on the preset low temperature correction term, determine the saturated water vapor pressure value corresponding to the ambient temperature; Based on the saturated water vapor pressure and relative humidity, the actual water vapor pressure in the current environment is obtained; The corresponding dew point temperature is obtained by iteratively solving the dew point temperature relationship based on the actual water vapor pressure value, according to the dew point temperature relationship determined by the preset low temperature correction term.

[0010] In some possible implementations, after solving the fuzzy set to obtain the precise value of the defrosting demand, the method further includes: When the defrosting demand precision value is greater than or equal to the second preset threshold and less than or equal to the first preset threshold, the reference heat absorbed by the evaporator is calculated based on the current refrigerant state at the inlet and outlet of the evaporator in the heat pump. Calculate the base power of the fan based on the current input voltage and input current of the fan in the heat pump.

[0011] In some possible implementations, when the defrosting demand precision value is greater than the first preset threshold, after defrosting the evaporator based on the difference between the heat currently absorbed by the evaporator in the heat pump and the reference heat, and the difference between the current power of the fan in the heat pump and the reference power, the method further includes: Detect the evaporator temperature during defrosting; If the evaporator temperature remains above the preset temperature for a period exceeding the preset duration, defrosting will stop.

[0012] In some possible implementations, after stopping defrosting if the evaporator temperature remains above a preset temperature for a preset duration, the method further includes: Calculate the recovered heat absorbed by the evaporator in the heat pump and the recovered power of the fan in the heat pump when defrosting is stopped. Based on the baseline heat and the baseline power, a corresponding first heat value, first power value, second heat value and second power value are determined according to a preset ratio, wherein the second heat value is less than the first heat value and the second power value is less than the first power value. If the heat after recovery is greater than the first heat value, or the power after recovery is greater than the first power value, the preset temperature is reduced by a preset value. If the heat after recovery is less than the second heat value, or the power after recovery is less than the second power value, the preset temperature is increased by a preset value.

[0013] In some possible implementations, the step of performing fuzzy inference based on the ambient temperature, the relative humidity, and the dew point temperature to obtain a fuzzy set of the defrosting demand of the heat pump includes: The ambient temperature, relative humidity, and dew point temperature are converted into corresponding fuzzy values. The fuzzy quantities are matched with a preset fuzzy rule library to determine the trigger strength corresponding to each fuzzy rule in the fuzzy rule library. Based on the application of the corresponding fuzzy rules to the original fuzzy set for each of the aforementioned trigger intensities, a fuzzy set of the defrosting demand of the heat pump is obtained.

[0014] In some possible implementations, solving the fuzzy set to obtain the precise value of the defrosting demand includes: The fuzzy set is sampled to obtain the membership values ​​corresponding to each quantization level of the fuzzy set; Multiply each quantization level by its corresponding membership value to obtain the corresponding weighted moments; Based on the sum of each of the aforementioned weighted moments, the precise value of defrosting demand is obtained.

[0015] Secondly, this application provides a carbon dioxide heat pump defrosting control device, the device comprising: The acquisition module is used to acquire the ambient temperature of the environment where the heat pump is located and the relative humidity of the air in the environment where the heat pump is located; The calculation module is used to calculate the corresponding dew point temperature based on the ambient temperature and the relative humidity; The inference module is used to perform fuzzy inference based on the ambient temperature, the relative humidity and the dew point temperature to obtain a fuzzy set of the defrosting demand of the heat pump; The solution module is used to solve the fuzzy set to obtain the accurate value of the defrosting demand. The defrosting module is used to defrost the evaporator based on the difference between the heat currently absorbed by the evaporator in the heat pump and the reference heat, and the difference between the current power of the fan in the heat pump and the reference power, when the defrosting demand accuracy value is greater than a first preset threshold.

[0016] Thirdly, this application provides a carbon dioxide heat pump defrosting control device, the device comprising: a processor, and a memory storing computer program instructions; the processor reads and executes the computer program instructions to implement the carbon dioxide heat pump defrosting control method as described above.

[0017] Fourthly, this application provides a computer-readable storage medium storing computer program instructions that, when executed by a processor, implement the carbon dioxide heat pump defrosting control method described above.

[0018] Fifthly, this application provides a computer program product in which instructions, when executed by a processor of an electronic device, cause the electronic device to perform the carbon dioxide heat pump defrosting control method as described above.

[0019] The carbon dioxide heat pump defrosting control method, device, equipment, storage medium, and product provided in this application calculate the dew point temperature by considering ambient temperature and relative humidity, and then use fuzzy reasoning to obtain the defrosting demand level, which is then converted into a precise value for judgment. When this value exceeds a set threshold, defrosting is triggered by comparing the current evaporator heat absorption with the reference heat and the current fan power with the reference power. The above scheme combines key physical parameters of frosting with the actual operating status of the system, realizing a multi-dimensional comprehensive judgment of the defrosting timing. This avoids false defrosting or defrosting delays caused by relying on a single or fixed threshold, improves the system's adaptability and control accuracy under varying operating conditions, thereby reducing unnecessary defrosting energy consumption while ensuring heat exchange efficiency and improving the accuracy of evaporator defrosting judgment. Attached Figure Description

[0020] This application can be better understood from the following description of specific embodiments in conjunction with the accompanying drawings, wherein: Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings, wherein the same or similar reference numerals denote the same or similar features.

[0021] Figure 1 This is a flowchart of a carbon dioxide heat pump defrosting control method provided in one embodiment of this application; Figure 2 This is a flowchart of a carbon dioxide heat pump defrosting control method provided in another embodiment of this application; Figure 3 This is a flowchart of a carbon dioxide heat pump defrosting control method provided in another embodiment of this application; Figure 4 This is a flowchart of a carbon dioxide heat pump defrosting control method provided in a further embodiment of this application; Figure 5 This is a schematic diagram of the structure of a carbon dioxide heat pump defrosting control device provided in one embodiment of this application; Figure 6 This is a schematic diagram of the hardware structure of the carbon dioxide heat pump defrosting control device provided in the embodiments of this application. Detailed Implementation

[0022] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0023] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0024] When air source heat pumps operate in low-temperature, high-humidity environments, frost easily forms on the surface of the evaporator fins, leading to increased heat transfer resistance, increased airflow resistance, and a decrease in the system's coefficient of performance (COP). Traditional defrosting control methods have significant technical shortcomings, especially unsuitable for the special conditions of carbon dioxide. Existing technologies may rely on fixed cycles or single fin temperature thresholds to initiate defrosting, neglecting the impact of humidity on frost formation. Alternatively, the degree of frost can be determined by detecting the air pressure difference between the evaporator inlet and outlet, but dust adsorption on the evaporator fin surface or ambient wind fluctuations can increase the false alarm rate due to the pressure difference, and the sensitivity is insufficient when the frost layer is thin. The problems of inaccurate judgment, poor adaptability, and high energy consumption in traditional methods necessitate dynamic matching of defrosting timing and intensity to improve system energy efficiency and operational reliability.

[0025] To address the problems of the prior art, embodiments of this application provide a carbon dioxide heat pump defrosting control method, apparatus, equipment, storage medium, and product. The carbon dioxide heat pump defrosting control method provided in this application embodiment will be described first below.

[0026] Figure 1 A schematic flowchart of a carbon dioxide heat pump defrosting control method according to an embodiment of this application is shown. Figure 1 As shown, the method includes the following steps: S101 to S105.

[0027] S101: Obtain the ambient temperature and relative humidity of the environment where the heat pump is located.

[0028] S102: Calculate the corresponding dew point temperature based on the ambient temperature and relative humidity.

[0029] S103: Based on ambient temperature, relative humidity and dew point temperature, perform fuzzy inference to obtain the fuzzy set of the defrosting demand of the heat pump.

[0030] S104: Solve the fuzzy set to obtain the precise value of defrosting demand.

[0031] S105: When the defrosting demand accuracy value is greater than the first preset threshold, defrost the evaporator based on the difference between the heat absorbed by the evaporator in the heat pump and the reference heat, and the difference between the current power of the fan in the heat pump and the reference power.

[0032] In the specific implementation of S101, a sensing unit deployed on the air inlet side of the heat pump outdoor unit or in the adjacent environmental area uses a temperature sensor to convert the ambient temperature into an electrical signal, and a humidity sensor outputs a corresponding electrical signal by detecting the change in capacitance of the humidity-sensitive capacitor as the relative humidity changes.

[0033] In the specific implementation of S102, the acquired ambient temperature and relative humidity are used as input parameters. Based on the empirical relationship model between saturated water vapor pressure and temperature, the dew point temperature is calculated by iteratively approximating the solution. The temperature value required to cool the air to saturation, i.e., the dew point temperature, is then calculated.

[0034] In order to obtain an accurate dew point temperature, in some embodiments, S102 may include the following steps: S1021 to S1023.

[0035] S1021: Determine the saturated vapor pressure value corresponding to the ambient temperature based on the preset low temperature correction term.

[0036] S1022: Based on the saturated water vapor pressure and relative humidity, obtain the actual water vapor pressure in the current environment.

[0037] S1023: The corresponding dew point temperature is obtained by iteratively solving the dew point temperature relationship based on the actual water vapor pressure value, according to the dew point temperature relationship determined by the preset low temperature correction term.

[0038] In the specific implementation of S1021, a mapping table containing different ambient temperatures and corresponding saturated vapor pressure values ​​is constructed in advance through experimental measurements or theoretical calculations. Since the relationship between vapor pressure and temperature exhibits strong nonlinearity in the low-temperature range, a preset low-temperature correction term is introduced to ensure the accuracy of the lookup results. During execution, the acquired ambient temperature value is used as the index address, and a linear search or binary search is performed in the mapping table to find two entries adjacent to that temperature value. If the ambient temperature is exactly equal to the temperature value of a certain entry, the corresponding saturated vapor pressure value is directly read as the output. If the ambient temperature is between two entries, linear interpolation is performed, and the saturated vapor pressure value at the current temperature is calculated using the temperature values ​​of the two adjacent entries and their corresponding saturated vapor pressure values ​​through proportional interpolation.

[0039] In the specific implementation of S1022, the calculated saturated water vapor pressure and relative humidity values ​​are read. Then, a multiplication instruction is executed to multiply the saturated water vapor pressure by the relative humidity value, thereby calculating the actual water vapor partial pressure in the current ambient air, i.e., the actual water vapor pressure.

[0040] In the specific implementation of S1023, the current ambient temperature is first used as the initial guessed temperature, and the saturated vapor pressure at this guessed temperature is calculated. Then, this calculated value is compared with the actual vapor pressure. If the difference is less than a preset convergence tolerance, the current guessed temperature is determined to be the dew point temperature. If the calculated value is greater than the actual vapor pressure, it indicates that the guessed temperature is too high, and the guessed temperature needs to be reduced by a predetermined step size. If the calculated value is less than the actual vapor pressure, it indicates that the guessed temperature is too low, and the guessed temperature needs to be increased by a predetermined step size. This iterative process of adjusting the guessed temperature, recalculating the saturated vapor pressure, and comparing it with the actual vapor pressure is repeated. Each iteration reduces the deviation between the guessed temperature and the true dew point until the convergence condition is met. A low-temperature correction is introduced each time the saturated vapor pressure calculation is called to ensure that each approximation step in the iteration process is based on an accurate vapor pressure relationship.

[0041] The above-described embodiments of this application determine the saturated vapor pressure value corresponding to the ambient temperature based on a preset low-temperature correction term. Then, based on the saturated vapor pressure value and relative humidity, the actual vapor pressure value in the current environment is obtained. Subsequently, the corresponding dew point temperature is obtained by iteratively solving the dew point temperature relationship determined by the preset low-temperature correction term based on the actual vapor pressure value, thereby obtaining an accurate dew point temperature.

[0042] In the specific implementation of S103, based on ambient temperature, relative humidity, and dew point temperature, fuzzy linguistic values ​​are mapped to their respective domains. For example, ambient temperature is divided into fuzzy subsets such as "negative high," "negative medium," "zero," and "positive medium"; relative humidity is divided into fuzzy subsets such as "dry," "comfortable," "humid," and "saturated"; and dew point temperature is divided into fuzzy subsets such as "extremely low," "low," "medium," and "high." Each fuzzy subset is represented by a triangular or trapezoidal membership function defined on the corresponding domain. The membership degree relative to each subset is calculated based on the current input value. Then, fuzzy inference is performed, and the fuzzy control rule table is read. The premise of each rule involves a specific combination of linguistic values ​​of ambient temperature, relative humidity, and dew point temperature, and the conclusion corresponds to the linguistic value of defrosting demand. The activation intensity of each rule is calculated by taking the smallest value, and the conclusions of all activated rules are aggregated by taking the largest value to generate a membership degree distribution that covers the entire defrosting demand domain and is composed of multiple irregular polygons, thus obtaining the fuzzy set of defrosting demand.

[0043] In order to obtain a reasonable fuzzy set, in some implementations, S103 may include the following steps: S1031 to S1033.

[0044] S1031: Convert ambient temperature, relative humidity, and dew point temperature into corresponding fuzzy quantities.

[0045] S1032: Match each fuzzy quantity with the preset fuzzy rule library to determine the trigger strength corresponding to each fuzzy rule in the fuzzy rule library.

[0046] S1033: Based on each trigger intensity, apply the corresponding fuzzy rules to the original fuzzy set to obtain the fuzzy set of the defrosting demand of the heat pump.

[0047] In the specific implementation of S1031, the membership function library pre-stored in the read-only memory is accessed. This function library defines a set of fuzzy linguistic values ​​and their corresponding membership functions for each input variable. The current precise input value is substituted into the membership function corresponding to each linguistic value for calculation: First, it is determined which piecewise linear interval of the function definition interval the input value falls into. Then, the membership degree of the input value relative to the linguistic value is calculated through proportional multiplication and addition operations. After the input value has traversed all linguistic values, each input variable obtains a set of membership values. This set of membership values, together with its corresponding linguistic value label, constitutes the fuzzy representation of the precise quantity, i.e., the fuzzy quantity.

[0048] In the specific implementation of S1032, a pre-designed and stored fuzzy rule base is read. This rule base consists of several fuzzy conditional statements. The premise of each rule involves a specific combination of linguistic values ​​for three input variables: ambient temperature, relative humidity, and dew point temperature. The conclusion corresponds to a linguistic value of defrosting demand. For the rule currently being processed, the membership degree corresponding to the linguistic value specified in the premise is extracted from the calculated membership degrees of each input variable. Subsequently, the membership degrees of all linguistic values ​​in the premise are compared, and the smallest membership degree is taken as the trigger strength of the rule. This trigger strength characterizes the degree of matching between the current operating condition and the situation described by this rule. The calculated trigger strength is associated with and stored with the conclusion linguistic value of the rule. After all rules have been processed, an intermediate result set consisting of the rule conclusion linguistic values ​​and their corresponding trigger strengths is obtained.

[0049] In the specific implementation of S1033, the original fuzzy sets of each linguistic value corresponding to the output variable "defrosting demand" are retrieved from the membership function library. Each original fuzzy set is a standard triangular or trapezoidal membership function curve defined on the domain of defrosting demand. Then, the rule processing results generated in S1032 are iterated. For each rule, the original fuzzy set corresponding to its conclusion is truncated or scaled according to the trigger strength of the rule. Specifically, the trigger strength is used as a threshold to truncate the membership function curve of the original fuzzy set. That is, for each point on the domain, if the original membership degree is greater than the trigger strength, it is modified to the trigger strength value; otherwise, it remains unchanged, thus generating an adjusted membership function curve with a flattened top, which serves as the actual output fuzzy set for that rule. After processing all rules, these adjusted output fuzzy sets generated by all rules are superimposed and merged on the domain of defrosting demand. The superposition operation uses the maximum value method, that is, for each point in the universe of discourse, the membership values ​​of all rules at that point are compared, and the maximum value is taken as the final comprehensive membership degree of that point. In this way, the original rule outputs are merged into a whole membership degree distribution composed of several irregular polygons or curve segments. This distribution is the fuzzy set of the final heat pump defrosting demand degree.

[0050] The above-described implementation of this application converts ambient temperature, relative humidity, and dew point temperature into corresponding fuzzy quantities. Then, each fuzzy quantity is matched with a preset fuzzy rule library to determine the trigger intensity of each fuzzy rule in the fuzzy rule library. Based on each trigger intensity, the corresponding fuzzy rules are applied to the original fuzzy set to obtain a fuzzy set of the defrosting demand of the heat pump, thereby obtaining a reasonable fuzzy set.

[0051] In the specific implementation of S104, several discrete points are taken within the universe of discourse of the defrosting demand degree at a fixed step size. For each discrete point, the membership value of that point is calculated. Then, the universe coordinates of all discrete points are multiplied by the corresponding membership values ​​and summed. At the same time, all membership values ​​are summed. Finally, the sum of multiplications is divided by the sum of membership values, and the quotient is the centroid position of the synthesized fuzzy set, which is used as the precise value of the defrosting demand degree.

[0052] In order to accurately determine the precise value of defrosting requirement, in some embodiments, S104 may include the following steps: S1041 to S1043.

[0053] S1041: Sample the fuzzy set to obtain the membership values ​​corresponding to each quantization level of the fuzzy set.

[0054] S1042: Multiply each quantization level by its corresponding membership value to obtain the corresponding weighted moments.

[0055] S1043: Based on the sum of each weighted moment, obtain the accurate value of defrosting demand.

[0056] In the specific implementation of S1041, based on the fuzzy set of heat pump defrosting demand generated in S103, this fuzzy set is represented on a continuous universe of discourse as a membership function waveform composed of several irregular curve segments. The continuous universe of discourse is divided into several discrete quantization levels according to a preset quantization interval, it is determined which linear interval the current quantization level is located in, and the precise membership value is obtained through proportional interpolation.

[0057] In the specific implementation of S1042, the first quantization level and its corresponding membership value are read from the sampling array generated in S1041. Then, the value of the quantization level is multiplied by its membership value, and the product is the weighted moment corresponding to the quantization level.

[0058] In the specific implementation of S1043, all weighted moments are read one by one from the temporary array and accumulated to obtain the sum of all weighted moments. Similarly, the membership values ​​corresponding to each quantization level sampled in S1041 are read one by one and accumulated to obtain the sum of all membership values. After all weighted moments and membership values ​​have been accumulated, the sum of the weighted moments is used as the dividend, and the sum of the membership values ​​is used as the divisor to calculate the quotient. This quotient value is the coordinate of the centroid of the current fuzzy set on the defrost demand domain, which is the precise value of the defrost demand obtained after defuzzification.

[0059] The above-described implementation method of this application samples the fuzzy set to obtain the membership value corresponding to each quantization level of the fuzzy set, and then multiplies each quantization level with the corresponding membership value to obtain the corresponding weighted moments. Then, based on the sum of each weighted moment, the defrosting demand precision value is obtained, thereby accurately determining the defrosting demand precision value.

[0060] To obtain reasonable reference heat and reference power, in some implementations, reference is made to... Figure 2 After S104, the following steps may also be included: S201 to S202.

[0061] S201: When the defrosting demand accuracy value is greater than or equal to the second preset threshold and less than or equal to the first preset threshold, calculate the reference heat absorbed by the evaporator based on the current refrigerant state at the inlet and outlet of the evaporator in the heat pump.

[0062] S202: Calculate the base power of the fan based on the current input voltage and input current of the fan in the heat pump.

[0063] In the specific implementation of S201, the precise value of the continuous defrosting demand is calculated and compared with a second preset threshold and a first preset threshold pre-stored in a read-only memory. When the current precise value of the defrosting demand is detected to be greater than or equal to the second preset threshold and simultaneously less than or equal to the first preset threshold, the real-time output values ​​of the first temperature sensor and the first pressure sensor installed on the refrigerant inlet pipe of the evaporator are read to obtain the temperature and pressure data of the refrigerant at the evaporator inlet; simultaneously, the real-time output values ​​of the second temperature sensor and the second pressure sensor installed on the refrigerant outlet pipe of the evaporator are read to obtain the temperature and pressure data of the refrigerant at the evaporator outlet. Through table lookup and interpolation calculations, the enthalpy values ​​of the refrigerant at the inlet and outlet are determined respectively, thereby calculating the reference heat absorbed by the evaporator.

[0064] In the specific implementation of S202, the instantaneous voltage and instantaneous current signals at the input terminal of the fan motor are acquired. Based on calibration coefficients, these signals are restored to the effective values ​​of the fan input voltage and input current. Subsequently, the effective voltage and current values ​​are multiplied, and then multiplied by the power factor of the fan circuit to obtain the real-time input active power of the fan. This real-time active power value is then recognized as the fan's reference power.

[0065] The above-described embodiments of this application calculate the reference heat absorbed by the evaporator based on the current refrigerant state at the inlet and outlet of the evaporator in the heat pump when the defrosting demand accuracy value is greater than or equal to a second preset threshold and less than or equal to a first preset threshold. Then, the reference power of the fan is calculated based on the current input voltage and input current of the fan in the heat pump, thereby obtaining a reasonable reference heat and reference power.

[0066] In the specific implementation of S105, the precise value of defrosting demand is compared with a first preset threshold. If the precise value is greater than the threshold, the defrosting trigger process is initiated; otherwise, monitoring continues. After initiating the defrosting trigger process, the temperature sensor values ​​installed on the refrigerant inlet and outlet pipes of the evaporator are read, and combined with the instantaneous flow rate value fed back by the refrigerant flow sensor, the heat absorbed by the evaporator per unit time is calculated based on the refrigerant thermodynamic property table. Simultaneously, the preset baseline heat value under frost-free conditions is retrieved from the memory, and the current heat absorption is subtracted from the baseline heat value to obtain the heat difference. The real-time input power of the fan is obtained by collecting the effective values ​​of the current and voltage of the fan drive motor and performing power calculations. The preset baseline power value under frost-free conditions is retrieved, and the current power is subtracted from the baseline power to obtain the power difference. Based on the magnitude of the difference, the corresponding defrosting action command is matched from the pre-stored control strategy table.

[0067] The carbon dioxide heat pump defrosting control method provided in this application calculates the dew point temperature based on ambient temperature and relative humidity, and combines these two factors to obtain the defrosting demand through fuzzy reasoning, then converts it into a precise value for judgment. When this value exceeds a set threshold, defrosting is triggered by comparing the current evaporator heat absorption with a reference heat and the current fan power with a reference power. This scheme combines key physical parameters of frosting with the actual operating state of the system, achieving a multi-dimensional comprehensive judgment of the defrosting timing. It avoids false defrosting or defrosting delays caused by relying on a single or fixed threshold, improves the system's adaptability and control accuracy under varying operating conditions, thereby reducing unnecessary defrosting energy consumption while ensuring heat exchange efficiency and improving the accuracy of evaporator defrosting judgment.

[0068] In order to perform defrosting operations at the precise time, in some implementation methods, reference is made to... Figure 3 S105 may include the following steps: S301 to S302.

[0069] S301: When the defrosting demand accuracy value is greater than the first preset threshold, calculate the current heat absorbed by the evaporator and the current power of the fan in the heat pump based on the current state of the evaporator and the current state of the fan, respectively.

[0070] S302: Defrost the evaporator when the heat level decreases by a first preset value compared to the reference heat level, or when the current power increases by a second preset value compared to the reference power level.

[0071] In the specific implementation of S301, the precise value of defrosting demand is compared with a first preset threshold stored in a read-only memory. When the precise value is determined to be greater than the first preset threshold, a parallel calculation process for the current heat absorption and current power is initiated. Temperature and pressure data of the refrigerant at the inlet and outlet are acquired. Based on these two sets of state parameters, the enthalpy values ​​of the refrigerant at the inlet and outlet are determined. Subsequently, the enthalpy value of the refrigerant at the outlet is subtracted from the enthalpy value at the inlet to obtain the increase in heat absorption per unit mass of refrigerant in the evaporator. This increase is then multiplied by the current refrigerant mass flow rate to calculate the total heat absorbed by the evaporator per unit time at the current moment. Instantaneous voltage and current signals at the input of the fan motor are collected to obtain the current power.

[0072] In the specific implementation of S302, the calculated current heat absorbed by the evaporator and the current power value of the fan are read. Then, the current heat value is subtracted from the reference heat value to obtain the heat drop difference, which is compared with a pre-set first preset value. If the heat drop difference is greater than or equal to the first preset value, one of the defrosting conditions is determined to be met. The reference power value is subtracted from the current power value to obtain the power increase difference, which is compared with a pre-set second preset value. If the power increase difference is greater than or equal to the second preset value, another defrosting condition is determined to be met. If either of the above two conditions is met, it is considered that the current degree of frost has seriously affected the heat exchange performance or airflow output, and defrosting needs to be initiated to defrost the evaporator.

[0073] The carbon dioxide heat pump defrosting control method provided in this application calculates the current heat absorbed by the evaporator and the current power of the fan in the heat pump based on the current state of the evaporator and the current state of the fan, respectively, when the defrosting demand accuracy value is greater than a first preset threshold. Then, when the heat is lower than the reference heat by a first preset value, or the current power is higher than the reference power by a second preset value, the evaporator is defrosted, thereby performing defrosting operations at the accurate time.

[0074] In order to obtain reasonable current heat absorbed by the evaporator and current fan power, in some embodiments, S301 may include the following steps: S3011 to S3012.

[0075] S3011: Calculate the heat currently absorbed by the evaporator in the heat pump based on the current refrigerant state at the inlet and outlet of the evaporator.

[0076] S3012: Calculate the current power of the fan in the heat pump based on the current input voltage and input current of the fan.

[0077] In the specific implementation of S3011, the current temperature and pressure values ​​of the refrigerant at the inlet and outlet are obtained. These two sets of state parameters are used as indexes to access the refrigerant thermodynamic property parameter table, which stores the specific enthalpy values ​​of the refrigerant under the corresponding conditions, with pressure and temperature as the dimensions. The specific enthalpy values ​​of the refrigerant at the inlet and outlet are determined. Subsequently, the total heat absorbed by the evaporator per unit time at the current moment is calculated, that is, the heat currently absorbed by the evaporator.

[0078] In the specific implementation of S3012, the real-time input active power of the wind turbine is calculated by multiplying the effective value of the voltage, the effective value of the current, and the power factor based on the current input voltage and input current of the wind turbine. That is, the current power of the wind turbine.

[0079] The carbon dioxide heat pump defrosting control method provided in this application calculates the heat currently absorbed by the evaporator in the heat pump based on the current refrigerant state at the inlet and outlet of the evaporator. Then, it calculates the current power of the fan in the heat pump based on the current input voltage and input current of the fan, thereby obtaining a reasonable current heat absorbed by the evaporator and the current power of the fan.

[0080] In order to accurately calculate the heat absorbed by the evaporator, in some embodiments, S3011 may include the following steps: S30111 to S30113.

[0081] S30111: Based on the current refrigerant temperature and specific heat capacity at the inlet of the evaporator in the heat pump, obtain the first specific enthalpy of the refrigerant at the inlet.

[0082] S30112: Based on the current refrigerant temperature and specific heat capacity at the outlet of the evaporator in the heat pump, the second specific enthalpy of the refrigerant at the outlet is obtained.

[0083] S30113: Calculate the heat currently absorbed by the evaporator based on the difference between the first and second specific enthalpy and the current refrigerant flow rate of the evaporator.

[0084] In the specific implementation of S30111, based on the current inlet temperature value and the corresponding isobaric specific heat capacity value at that temperature, the temperature difference between the current inlet temperature and the reference temperature is multiplied by the average isobaric specific heat capacity within that temperature range, and then the reference specific enthalpy is added to calculate the current specific enthalpy value at the refrigerant inlet, which is the first specific enthalpy.

[0085] In the specific implementation of S30112, the same zero-degree Celsius reference specific enthalpy value is used as the inlet calculation to ensure consistency. The difference between the current outlet temperature and the reference temperature is multiplied by the average isobaric specific heat capacity within that temperature range, and then added to the reference specific enthalpy to calculate the current specific enthalpy value of the refrigerant at the outlet, i.e., the second specific enthalpy.

[0086] In the specific implementation of S30113, the enthalpy difference is obtained by subtracting the inlet enthalpy from the outlet enthalpy. This yields the heat increment per unit mass absorbed by the refrigerant after it flows through the evaporator. The output signal of the mass flow sensor installed on the refrigerant pipeline is read by the flow acquisition circuit and converted into the instantaneous value of the current refrigerant mass flow rate. Multiplying the enthalpy difference by the current mass flow rate, the total heat absorbed by the evaporator from the environment per unit time at the current moment is calculated, i.e., the heat currently absorbed by the evaporator.

[0087] The carbon dioxide heat pump defrosting control method provided in this application obtains the first specific enthalpy of the refrigerant at the inlet of the heat pump based on the current refrigerant temperature and specific heat capacity at the inlet of the evaporator. Then, it obtains the second specific enthalpy of the refrigerant at the outlet based on the current refrigerant temperature and specific heat capacity at the outlet of the evaporator. Based on the difference between the first and second specific enthalpies and the current refrigerant flow rate of the evaporator, it calculates the heat currently absorbed by the evaporator, thereby accurately calculating the heat currently absorbed by the evaporator.

[0088] To shorten the defrosting cycle, in some implementation methods, reference is made to... Figure 4 S105 may include the following steps: S401 to S402.

[0089] S401: Detect the evaporator temperature during defrosting.

[0090] S402: Defrosting will stop if the evaporator temperature remains above the preset temperature for a period of time exceeding the preset duration.

[0091] In the specific implementation of S401, when defrosting is in progress, the electrical signal output by the temperature sensor installed on the surface of the evaporator coil or embedded in the fins is read by an analog-to-digital converter to detect the evaporator temperature.

[0092] In the specific implementation of S402, if the current temperature value is greater than the preset temperature, an increment signal is sent to the timer to accumulate the duration since the last reset; if the current temperature value is less than or equal to the preset temperature, the timer is immediately reset to zero and monitoring resumes. When the accumulated value of the timer first reaches or exceeds the preset duration, the microcontroller determines that defrosting is complete and then outputs a control command to stop defrosting.

[0093] The carbon dioxide heat pump defrosting control method provided in this application detects the evaporator temperature during defrosting and stops defrosting if the evaporator temperature remains above a preset temperature for a longer than preset time, thereby reducing ineffective defrosting and shortening the defrosting cycle.

[0094] To improve defrosting efficiency, in some embodiments, S402 may include the following steps: S4021 to S4024.

[0095] S4021: Calculate the recovered heat absorbed by the evaporator in the heat pump and the recovered power of the fan in the heat pump when defrosting is stopped.

[0096] S4022: Based on the baseline heat and baseline power, determine the corresponding first heat value, first power value, second heat value and second power value according to a preset ratio, wherein the second heat value is less than the first heat value and the second power value is less than the first power value.

[0097] S4023: If the heat after recovery is greater than the first heat value, or the power after recovery is greater than the first power value, the preset temperature will be reduced by the preset value.

[0098] S4024: If the heat after recovery is less than the second heat value, or the power after recovery is less than the second power value, the preset temperature will be increased by the preset value.

[0099] In the specific implementation of S4021, when defrosting is stopped, the temperature and pressure data of the refrigerant at the inlet are acquired; simultaneously, the real-time output values ​​of the second temperature sensor and the second pressure sensor at the outlet pipe are read to acquire the temperature and pressure data of the refrigerant at the outlet; the inlet specific enthalpy and outlet specific enthalpy are determined by table lookup and interpolation calculations, and then multiplied by the current refrigerant mass flow rate read from the flow sensor to calculate the heat absorbed by the evaporator per unit time at the current moment. The effective voltage and current values ​​at the input terminal of the fan motor are acquired in real time through voltage sampling circuit and current sampling circuit, multiplied by the pre-stored power factor to calculate the real-time input active power of the fan, and this power value is used as the restored power.

[0100] In the specific implementation of S4022, the first heat ratio coefficient, the first power ratio coefficient, the second heat ratio coefficient, and the second power ratio coefficient are read, wherein the first heat ratio coefficient is greater than the second heat ratio coefficient, and the first power ratio coefficient is greater than the second power ratio coefficient. The reference heat value is multiplied by the first heat ratio coefficient to obtain the first heat value; the reference power value is multiplied by the first power ratio coefficient to obtain the first power value; the reference heat value is multiplied by the second heat ratio coefficient to obtain the second heat value; and the reference power value is multiplied by the second power ratio coefficient to obtain the second power value.

[0101] In the specific implementation of S4023, if the heat generated after recovery is greater than the first heat value, or the power generated after recovery is greater than the first power value, the current recovery state is considered to be over-recovery, indicating that the defrosting stop time may be too late, leading to overheating of the coil or high power consumption of the fan. The updated preset temperature is obtained by subtracting the preset adjustment step size from the preset temperature value.

[0102] In the specific implementation of S4024, if the recovered heat is less than the second heat value, or the recovered power is less than the second power value, the current recovery state is considered insufficient. This indicates that the defrosting stop time may be too early, the frost layer may not be completely melted, resulting in low heat absorption or abnormal power consumption of the fan due to frost blockage. The preset temperature value is added to the preset adjustment step size to obtain the updated preset temperature.

[0103] The carbon dioxide heat pump defrosting control method provided in this application improves defrosting efficiency by calculating the recovered heat absorbed by the evaporator and the recovered power of the fan in the heat pump when defrosting is stopped. Then, based on the reference heat and reference power, a first heat value, a first power value, a second heat value, and a second power value are determined according to a preset ratio. The second heat value is less than the first heat value, and the second power value is less than the first power value. In this way, if the recovered heat is greater than the first heat value or the recovered power is greater than the first power value, the preset temperature is reduced by a preset value; or if the recovered heat is less than the second heat value or the recovered power is less than the second power value, the preset temperature is increased by a preset value.

[0104] In some implementations, ambient temperature, relative humidity, evaporator fin temperature, and operating time are collected in real time, and operating data are recorded by a metering unit. A moving average filter is used to remove noise from the data. A modified Magnus-Tetens formula is used to calculate the dew point temperature, and a low-temperature correction term is introduced to improve the accuracy in the low-temperature range.

[0105] Ambient temperature, relative humidity, and dew point temperature are converted into fuzzy quantities, matched with a fuzzy rule base, and the output defrost demand degree (DDS) fuzzy set is synthesized through Mamdani inference.

[0106] The exact value of DDS is calculated using the centroid method to determine which interval DDS falls within.

[0107] When DDS < 50%, normal heating is maintained.

[0108] When 50%≤DDS<65%, the condition is met, and the calculation of the heat absorbed by the evaporator Q1 and the fan power P1 is triggered for the first time.

[0109] Calculation of heat absorbed by the evaporator: Neglecting heat transfer losses in the evaporator, the heat absorbed by the evaporator, Q, can be calculated using the energy conservation formula, as follows: Q = Mco2△h Where Q represents the heat absorbed by the heat exchanger, and Mco2 represents the CO2 refrigerant flow rate F.

[0110] △h = Cp1 * Tein - Cp2 * Teout Where Cp1co2 is the isobaric specific heat capacity of CO2 at the evaporator inlet, Cp2co2 is the isobaric specific heat capacity of CO2 at the evaporator outlet, and Tein and Teout are the evaporator inlet and outlet temperatures, respectively.

[0111] Then, the heat absorbed by the evaporator, Q, is calculated. The formula for calculating the fan power is: P = *U*I*cosφ When DDS > 65%, the calculation of evaporator heat absorption Q2 and fan power P2 is triggered. This calculation is repeated every time interval T1. Defrosting is triggered when the evaporator heat absorption decreases by 20% and the fan power increases by 20%. The fin temperature is monitored in real time. Defrosting is exited and heating mode is resumed when the stop conditions are met. Defrosting stops when the fin temperature exceeds the set exit temperature for 30 seconds.

[0112] When the system resumes heating, monitor the fan power and calculate the heat absorbed by the evaporator, Q3. If Q3 is greater than 95% of Q1 or the fan power is greater than 95% of P1, the fin defrost temperature setpoint is reduced by 0.1℃. If Q3 is less than 90% of Q1 or the fan power is less than 90% of P1, the fin defrost temperature setpoint is increased by 0.1℃.

[0113] Based on the carbon dioxide heat pump defrosting control method provided in the above embodiments, this application also provides specific implementation methods of the carbon dioxide heat pump defrosting control device. Please refer to the following embodiments.

[0114] First see Figure 5 The carbon dioxide heat pump defrosting control device 500 provided in this application embodiment includes the following modules: The acquisition module 501 is used to acquire the ambient temperature and relative humidity of the air in the environment where the heat pump is located.

[0115] The calculation module 502 is used to calculate the corresponding dew point temperature based on the ambient temperature and relative humidity.

[0116] The inference module 503 is used to perform fuzzy inference based on ambient temperature, relative humidity and dew point temperature to obtain a fuzzy set of the defrosting demand of the heat pump.

[0117] Solver module 504 is used to solve the fuzzy set to obtain the accurate value of defrosting demand.

[0118] The defrosting module 505 is used to defrost the evaporator when the defrosting demand accuracy value is greater than a first preset threshold, based on the difference between the heat currently absorbed by the evaporator in the heat pump and the reference heat, and the difference between the current power of the fan in the heat pump and the reference power.

[0119] As one implementation of this application, the defrosting module 505 includes: The calculation unit is used to calculate the current heat absorbed by the evaporator and the current power of the fan in the heat pump, respectively, based on the current state of the evaporator and the current state of the fan, when the defrosting demand accuracy value is greater than a first preset threshold.

[0120] The defrosting unit is used to defrost the evaporator when the heat is lower than the reference heat by a first preset value, or when the current power is higher than the reference power by a second preset value.

[0121] As one implementation of this application, the computing unit includes: The calculation subunit is used to calculate the heat currently absorbed by the evaporator in the heat pump based on the current refrigerant state at the inlet and outlet of the evaporator.

[0122] The calculation subunit is also used to calculate the current power of the fan in the heat pump based on the current input voltage and input current of the fan.

[0123] As one implementation of this application, the computation subunit includes: A subunit is defined to obtain the first specific enthalpy of the refrigerant at the inlet based on the current refrigerant temperature and specific heat capacity at the inlet of the evaporator in the heat pump.

[0124] The determination of the sub-unit is also used to obtain the second specific enthalpy of the refrigerant at the outlet based on the current refrigerant temperature and specific heat capacity at the outlet of the evaporator in the heat pump.

[0125] The calculation subunit is used to calculate the heat currently absorbed by the evaporator based on the difference between the first specific enthalpy and the second specific enthalpy, and the current refrigerant flow rate of the evaporator.

[0126] As one implementation of this application, the solving module 504 includes: The calculation unit is used to calculate the reference heat absorbed by the evaporator based on the current refrigerant state at the inlet and outlet of the evaporator in the heat pump, when the defrosting demand accuracy value is greater than or equal to a second preset threshold and less than or equal to a first preset threshold.

[0127] The calculation unit is also used to calculate the reference power of the fan based on the current input voltage and input current of the fan in the heat pump.

[0128] As one implementation of this application, the carbon dioxide heat pump defrosting control device 500 further includes: The detection module is used to detect the evaporator temperature during defrosting.

[0129] The stop module is used to stop defrosting if the evaporator temperature remains above the preset temperature for a preset duration.

[0130] As one implementation of this application, the carbon dioxide heat pump defrosting control device 500 further includes: The calculation module is used to calculate the recovered heat absorbed by the evaporator in the heat pump and the recovered power of the fan in the heat pump when defrosting is stopped.

[0131] The determination module is used to determine the corresponding first heat value, first power value, second heat value and second power value according to a preset ratio based on the reference heat and reference power, wherein the second heat value is less than the first heat value and the second power value is less than the first power value.

[0132] The reduction module is used to reduce the preset temperature by a preset value if the heat after recovery is greater than the first heat value, or the power after recovery is greater than the first power value.

[0133] An additional module is added to increase the preset temperature by a preset value if the heat after recovery is less than the second heat value, or the power after recovery is less than the second power value.

[0134] As one implementation of this application, the inference module 503 includes: The conversion module is used to convert ambient temperature, relative humidity, and dew point temperature into corresponding fuzzy quantities.

[0135] The determination module is used to match each fuzzy quantity with a preset fuzzy rule library to determine the trigger strength corresponding to each fuzzy rule in the fuzzy rule library.

[0136] The application module is used to apply the corresponding fuzzy rules to the original fuzzy set based on each trigger intensity to obtain the fuzzy set of the defrosting demand of the heat pump.

[0137] As one implementation of this application, the solving module 504 includes: The sampling module is used to sample the fuzzy set and obtain the membership values ​​corresponding to each quantization level of the fuzzy set.

[0138] The determination module is used to multiply each quantization level by its corresponding membership value to obtain the corresponding weighted moments.

[0139] The determination module is also used to obtain an accurate value of defrosting demand based on the sum of each weighted moment.

[0140] Each module in the carbon dioxide heat pump defrosting control device provided in this application embodiment can realize each step in the above-mentioned carbon dioxide heat pump defrosting control method and achieve the corresponding effect. For the sake of brevity, it will not be described in detail here.

[0141] Figure 6 A schematic diagram of the structure of the carbon dioxide heat pump defrosting control hardware provided in an embodiment of this application is shown.

[0142] The carbon dioxide heat pump defrosting control device may include a processor 601 and a memory 602 storing computer program instructions.

[0143] Specifically, the processor 601 may include a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of this application.

[0144] Memory 602 may include mass storage for data or instructions. For example, and not limitingly, memory 602 may include a hard disk drive (HDD), floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, memory 602 may include removable or non-removable (or fixed) media. Where appropriate, memory 602 may be internal or external to the integrated gateway disaster recovery device. In a particular embodiment, memory 602 is non-volatile solid-state memory.

[0145] The memory may include read-only memory (ROM), random access memory (RAM), disk storage media devices, optical storage media devices, flash memory devices, and electrical, optical, or other physical / tangible memory storage devices. Therefore, typically, memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the carbon dioxide heat pump defrosting control method according to any embodiment of this disclosure.

[0146] The processor 601 reads and executes computer program instructions stored in the memory 602 to implement any of the carbon dioxide heat pump defrosting control methods in the above embodiments.

[0147] In one example, the carbon dioxide heat pump defrosting control device may also include a communication interface 603 and a bus 610. Wherein, as Figure 6As shown, the processor 601, memory 602, and communication interface 603 are connected through bus 610 and complete communication with each other.

[0148] The communication interface 603 is mainly used to realize communication between various modules, devices, units and / or equipment in the embodiments of this application.

[0149] Bus 610 includes hardware, software, or both, that couples components of an online data traffic metering device together. For example, and not limitingly, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), HyperTransport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an Infinite Bandwidth Interconnect, a Low Pin Count (LPC) bus, a memory bus, a Microchannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or other suitable buses, or combinations of two or more of these. Where appropriate, bus 610 may include one or more buses. Although specific buses are described and illustrated in embodiments of this application, any suitable bus or interconnect is contemplated herein.

[0150] Furthermore, in conjunction with the defrosting control method for carbon dioxide heat pumps described in the above embodiments, this application embodiment can provide a computer storage medium for implementation. This computer storage medium stores computer program instructions; when these computer program instructions are executed by a processor, they implement any of the carbon dioxide heat pump defrosting control methods described in the above embodiments.

[0151] This application also provides a computer program product, including a computer program that, when executed, implements any of the carbon dioxide heat pump defrosting control methods described in the above embodiments.

[0152] It should be clarified that this application is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of this application is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of this application.

[0153] The functional blocks shown in the above-described structural diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this application are programs or code segments used to perform the required tasks. Programs or code segments can be stored on a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried on a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0154] It should also be noted that the exemplary embodiments mentioned in this application describe methods or systems based on a series of steps or apparatus. However, this application is not limited to the order of the above steps; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0155] The aspects of this disclosure have been described above with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It should be understood that each block in the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that these instructions, executable via the processor of the computer or other programmable data processing apparatus, enable the implementation of the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field-programmable logic circuit. It is also understood that each block in the block diagrams and / or flowchart illustrations, and combinations of blocks in the block diagrams and / or flowchart illustrations, can also be implemented by an FPGA performing the specified functions or actions, or can be implemented by a combination of an FPGA and computer instructions.

[0156] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A defrosting control method for a carbon dioxide heat pump, characterized in that, The method includes: The ambient temperature and relative humidity of the air in the environment where the heat pump is located are obtained. Calculate the corresponding dew point temperature based on the ambient temperature and relative humidity; Based on the ambient temperature, relative humidity and dew point temperature, fuzzy inference is performed to obtain the fuzzy set of the defrosting demand of the heat pump; Solve the fuzzy set to obtain the precise value of defrosting demand; If the defrosting demand accuracy value is greater than a first preset threshold, the evaporator is defrosted based on the difference between the heat currently absorbed by the evaporator in the heat pump and the reference heat, and the difference between the current power of the fan in the heat pump and the reference power.

2. The carbon dioxide heat pump defrosting control method according to claim 1, characterized in that, When the defrosting demand precision value is greater than the first preset threshold, defrosting is performed on the evaporator based on the difference between the heat currently absorbed by the evaporator in the heat pump and the reference heat, and the difference between the current power of the fan in the heat pump and the reference power, including: If the defrosting demand accuracy value is greater than the first preset threshold, the heat currently absorbed by the evaporator and the current power of the fan in the heat pump are calculated based on the current state of the evaporator and the current state of the fan, respectively. The evaporator is defrosted when the heat level decreases by a first preset value compared to the reference heat level, or when the current power increases by a second preset value compared to the reference power level.

3. The carbon dioxide heat pump defrosting control method according to claim 2, characterized in that, The calculation of the current heat absorbed by the evaporator and the current power of the fan in the heat pump, based on the current states of the evaporator and the fan respectively, includes: Calculate the heat absorbed by the evaporator in the heat pump based on the current refrigerant state at the inlet and outlet of the evaporator. Calculate the current power of the fan in the heat pump based on the current input voltage and current of the fan.

4. The carbon dioxide heat pump defrosting control method according to claim 3, characterized in that, The calculation of the heat absorbed by the evaporator in the heat pump based on the current refrigerant state at the inlet and outlet of the evaporator includes: The first specific enthalpy of the refrigerant at the inlet is obtained based on the current refrigerant temperature and specific heat capacity at the inlet of the evaporator in the heat pump. Based on the current refrigerant temperature and specific heat capacity at the outlet of the evaporator in the heat pump, the second specific enthalpy of the refrigerant at the outlet is obtained. The heat absorbed by the evaporator is calculated based on the difference between the first and second specific enthalpy and the current refrigerant flow rate of the evaporator.

5. The carbon dioxide heat pump defrosting control method according to claim 1, characterized in that, The step of calculating the corresponding dew point temperature based on the ambient temperature and the relative humidity includes: Based on the preset low temperature correction term, determine the saturated water vapor pressure value corresponding to the ambient temperature; Based on the saturated water vapor pressure and relative humidity, the actual water vapor pressure in the current environment is obtained; The corresponding dew point temperature is obtained by iteratively solving the dew point temperature relationship based on the actual water vapor pressure value, according to the dew point temperature relationship determined by the preset low temperature correction term.

6. The carbon dioxide heat pump defrosting control method according to claim 1, characterized in that, After solving the fuzzy set to obtain the precise value of defrosting demand, the method further includes: When the defrosting demand precision value is greater than or equal to the second preset threshold and less than or equal to the first preset threshold, the reference heat absorbed by the evaporator is calculated based on the current refrigerant state at the inlet and outlet of the evaporator in the heat pump. Calculate the base power of the fan based on the current input voltage and input current of the fan in the heat pump.

7. The carbon dioxide heat pump defrosting control method according to claim 1, characterized in that, When the defrosting demand precision value is greater than the first preset threshold, after defrosting the evaporator based on the difference between the heat currently absorbed by the evaporator in the heat pump and the reference heat, and the difference between the current power of the fan in the heat pump and the reference power, the method further includes: Detect the evaporator temperature during defrosting; If the evaporator temperature remains above the preset temperature for a period exceeding the preset duration, defrosting will stop.

8. The carbon dioxide heat pump defrosting control method according to claim 7, characterized in that, If the evaporator temperature remains above the preset temperature for a period exceeding the preset time, after stopping defrosting, the method further includes: Calculate the recovered heat absorbed by the evaporator in the heat pump and the recovered power of the fan in the heat pump when defrosting is stopped. Based on the baseline heat and the baseline power, a corresponding first heat value, first power value, second heat value and second power value are determined according to a preset ratio, wherein the second heat value is less than the first heat value and the second power value is less than the first power value. If the heat after recovery is greater than the first heat value, or the power after recovery is greater than the first power value, the preset temperature will be reduced by a preset value. If the heat after recovery is less than the second heat value, or the power after recovery is less than the second power value, the preset temperature is increased by a preset value.

9. The carbon dioxide heat pump defrosting control method according to claim 1, characterized in that, The step of performing fuzzy inference based on the ambient temperature, relative humidity, and dew point temperature to obtain a fuzzy set of the defrosting demand of the heat pump includes: The ambient temperature, relative humidity, and dew point temperature are converted into corresponding fuzzy values. The fuzzy quantities are matched with a preset fuzzy rule library to determine the trigger strength corresponding to each fuzzy rule in the fuzzy rule library. Based on the application of the corresponding fuzzy rules to the original fuzzy set for each of the aforementioned trigger intensities, a fuzzy set of the defrosting demand of the heat pump is obtained.

10. The carbon dioxide heat pump defrosting control method according to claim 1, characterized in that, Solving the fuzzy set to obtain the precise value of defrosting demand includes: The fuzzy set is sampled to obtain the membership values ​​corresponding to each quantization level of the fuzzy set; Multiply each quantization level by its corresponding membership value to obtain the corresponding weighted moments; Based on the sum of the weighted moments, the precise value of defrosting demand is obtained.

11. A carbon dioxide heat pump defrosting control device, characterized in that, The device includes: The acquisition module is used to acquire the ambient temperature of the environment where the heat pump is located and the relative humidity of the air in the environment where the heat pump is located; The calculation module is used to calculate the corresponding dew point temperature based on the ambient temperature and the relative humidity; The inference module is used to perform fuzzy inference based on the ambient temperature, the relative humidity and the dew point temperature to obtain a fuzzy set of the defrosting demand of the heat pump; The solution module is used to solve the fuzzy set to obtain the accurate value of the defrosting demand. The defrosting module is used to defrost the evaporator based on the difference between the heat currently absorbed by the evaporator in the heat pump and the reference heat, and the difference between the current power of the fan in the heat pump and the reference power, when the defrosting demand accuracy value is greater than a first preset threshold.

12. A carbon dioxide heat pump defrosting control device, characterized in that, The device includes: a processor and a memory storing computer program instructions; the processor reads and executes the computer program instructions to implement the carbon dioxide heat pump defrosting control method as described in any one of claims 1-10.

13. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer program instructions, which, when executed by a processor, implement the carbon dioxide heat pump defrosting control method as described in any one of claims 1-10.

14. A computer program product, characterized in that, When the instructions in the computer program product are executed by the processor of the electronic device, the electronic device causes the electronic device to perform the carbon dioxide heat pump defrosting control method as described in any one of claims 1-10.

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