Indoor unit, control method of indoor unit and air conditioner

Abstract

The invention provides an indoor unit, a control method of the indoor unit and an air conditioner. The temperature detection device used for detecting the first type temperature value and the second type temperature value is arranged in the indoor unit, and the controller is combined to dynamically control the opening degree of the expansion valve based on the two types of temperature values, so that the flow of the refrigerant flowing into the heat exchanger is accurately adjusted. The first temperature value is used for representing the heat exchange state of the refrigerant side of the heat exchanger, the second temperature value is used for representing the heat exchange state of the air side of the indoor unit, and by comprehensively analyzing the heat exchange information of the refrigerant side and the air side, the defect that refrigerant flow control is inaccurate due to the fact that an expansion valve is controlled only through a single parameter in the related technology is effectively overcome. Under the condition that the indoor unit and the outdoor unit do not communicate, dynamic optimization of the refrigerant flow can be achieved, and the operation efficiency and the heat exchange effect of the air conditioner are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, and in particular to an indoor unit, a control method for the indoor unit, and an air conditioner. Background Art

[0002] Air conditioners without communication between indoor and outdoor units refer to air conditioners in which there is no direct data communication connection or signal transmission between the indoor and outdoor units in the air conditioning system. Such air conditioners are not equipped with complex communication modules and cannot transmit operating status data (such as compressor status, refrigerant flow, temperature, etc.) in real time through cables, wireless or other means.

[0003] In the related art, for an air conditioner without communication between an indoor unit and an outdoor unit, there is a technical problem that the refrigerant flow control in the indoor unit is not precise enough. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned technical deficiencies and provide an indoor unit, a control method for the indoor unit and an air conditioner to solve the technical problem in the related art that the refrigerant flow control in the indoor unit is not accurate enough for the air conditioner without communication between the indoor unit and the outdoor unit.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: In a first aspect, the present invention provides an indoor unit, which is applied to an air conditioner without communication between the indoor unit and the outdoor unit, and the indoor unit at least comprises: A heat exchanger, which is used to perform heat exchange on the refrigerant flowing through it; An expansion valve, which is used to control the flow of refrigerant into the heat exchanger; A temperature detection device, which is used to detect a first type of temperature value and a second type of temperature value; wherein the first type of temperature value is a temperature value used to characterize the heat exchange state of the refrigerant side of the heat exchanger, and the second type of temperature value is a temperature value used to characterize the heat exchange state of the indoor air side of the indoor unit; A controller is used to control the opening of the expansion valve based on the first temperature value and the second temperature value to adjust the flow rate of the refrigerant flowing into the heat exchanger.

[0006] In a second aspect, the present invention provides a control method for an indoor unit, wherein the indoor unit is applied to an air conditioner without communication between the indoor unit and the outdoor unit, and the control method comprises: During the operation of the indoor unit, a first temperature value and a second temperature value are obtained; wherein the first temperature value is a temperature value used to characterize the heat exchange state on the refrigerant side of the heat exchanger, and the second temperature value is a temperature value used to characterize the heat exchange state on the indoor air side of the indoor unit; Based on the first temperature value and the second temperature value, the opening of the expansion valve is controlled to adjust the flow rate of the refrigerant flowing into the heat exchanger.

[0007] In a third aspect, the present invention provides an air conditioner, wherein the air conditioner is an air conditioner without communication between an indoor unit and an outdoor unit, and the indoor unit is the indoor unit described above or an indoor unit that executes the method described above.

[0008] Beneficial effects: The present invention realizes accurate regulation of the refrigerant flow rate flowing into the heat exchanger by arranging a temperature detection device for detecting the first type of temperature value and the second type of temperature value in the indoor unit, and dynamically controlling the opening of the expansion valve based on the two types of temperature values ​​in combination with a controller. The first type of temperature value is used to characterize the heat exchange state on the refrigerant side of the heat exchanger, and the second type of temperature value is used to characterize the heat exchange state on the air side of the indoor unit. By comprehensively analyzing the heat exchange information on the refrigerant side and the air side, the defect of inaccurate refrigerant flow control caused by relying only on a single parameter to control the expansion valve in the related art is effectively overcome. The present invention can realize dynamic optimization of the refrigerant flow rate under the condition that there is no communication between the indoor unit and the outdoor unit, thereby improving the operating efficiency and heat exchange effect of the air conditioner. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a block diagram of an indoor unit provided by an embodiment of the present invention; Figure 2 is a block diagram of an indoor unit provided by an embodiment of the present invention; Figure 3 is a flow chart of a control method of an indoor unit provided by an embodiment of the present invention; Figure 4 is a flow chart of a control method of an indoor unit provided by an embodiment of the present invention; Figure 5 is a block diagram of an air conditioner without communication between an indoor unit and an outdoor unit provided by an embodiment of the present invention; Figure 6 It is a block diagram of a temperature controller provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0010] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0011] In the related art, the air conditioning system is usually composed of an indoor unit and an outdoor unit, which are connected by a refrigerant pipeline to achieve indoor air temperature regulation. In most traditional air conditioning systems, there is a communication connection between the indoor unit and the outdoor unit, and the compressor of the outdoor unit and the controller of the indoor unit can work together through a communication protocol. Based on this communication mechanism, the indoor unit can obtain the operating parameters of the outdoor unit in real time, such as the start and stop status of the compressor, the refrigerant pressure and the refrigerant flow, so as to accurately adjust the refrigerant flow and heat exchange efficiency to meet the needs of indoor temperature regulation. However, in air conditioners without communication between the indoor unit and the outdoor unit, since it is impossible to obtain the operating information of the outdoor unit in real time, the indoor unit can only rely on its own parameters to adjust the refrigerant flow, which brings new technical difficulties.

[0012] Specifically, in a non-communication air conditioner, the expansion valve in the indoor unit is the core component that controls the refrigerant flow into the heat exchanger, and its opening directly determines the refrigerant flow. However, since it is impossible to obtain the operating status of the compressor and the dynamic information of the refrigerant from the outdoor unit, the existing technology usually adopts a fixed expansion valve control strategy, which leads to the expansion valve opening adjustment is not accurate enough, which may cause insufficient or excessive refrigerant flow, thereby reducing the overall energy efficiency of the air conditioning system. In addition, when the operating environment changes greatly (indoor load fluctuations or ambient temperature changes), the fixed control strategy is difficult to adapt to the dynamic heat exchange requirements, which further leads to a decline in system performance.

[0013] In air conditioners without communication, the indoor unit lacks the ability to perceive the heat exchange status of the refrigerant side of the heat exchanger and the heat exchange status of the indoor air side. Usually, only a single parameter (indoor return air temperature) is relied on to adjust the expansion valve opening, ignoring the coupling effect between the heat exchange degree of the refrigerant side of the heat exchanger and the heat exchange efficiency of the air side. This approach not only fails to fully utilize the adjustment capacity of the expansion valve, but may also cause refrigerant flow imbalance problems, such as too much refrigerant causing an increase in the compressor load, or too little refrigerant causing the heat exchanger to be unable to fully evaporate the refrigerant, thereby reducing the cooling / heating effect.

[0014] Therefore, it is necessary to provide an improved technical solution by comprehensively analyzing the heat exchange status of the refrigerant side and the indoor air side of the heat exchanger, dynamically controlling the opening of the expansion valve, so as to achieve precise adjustment of the refrigerant flow, and thereby solve the technical problem of inaccurate refrigerant flow control of the indoor unit in the non-communication air conditioner.

[0015] like Figure 1 and Figure 2 As shown, this embodiment provides an indoor unit, which is applied to an air conditioner without communication between the indoor unit and the outdoor unit, and the indoor unit at least includes: A heat exchanger is used to exchange heat with the refrigerant flowing through it.

[0016] An expansion valve is used to control the flow of refrigerant into the heat exchanger.

[0017] A temperature detection device, which is used to detect a first type of temperature value and a second type of temperature value; wherein the first type of temperature value is a temperature value used to characterize the heat exchange state on the refrigerant side of the heat exchanger, and the second type of temperature value is a temperature value used to characterize the heat exchange state on the indoor air side of the indoor unit.

[0018] A controller is used to control the opening of the expansion valve based on the first temperature value and the second temperature value to adjust the flow rate of the refrigerant flowing into the heat exchanger.

[0019] This embodiment achieves precise regulation of the refrigerant flow rate flowing into the heat exchanger by setting a temperature detection device for detecting the first type of temperature value and the second type of temperature value in the indoor unit, and dynamically controlling the opening of the expansion valve based on these two types of temperature values ​​in combination with a controller. The first type of temperature value is used to characterize the heat exchange state on the refrigerant side of the heat exchanger, and the second type of temperature value is used to characterize the heat exchange state on the air side of the indoor unit. By comprehensively analyzing the heat exchange information on the refrigerant side and the air side, the defect of inaccurate refrigerant flow control caused by relying only on a single parameter to control the expansion valve in the related art is effectively overcome. The scheme of the present invention can achieve dynamic optimization of the refrigerant flow rate under the condition that there is no communication between the indoor unit and the outdoor unit, thereby improving the operating efficiency and heat exchange effect of the air conditioner.

[0020] In some embodiments, the indoor unit further includes: A fan is used to drive indoor air to flow through the heat exchanger to improve the heat exchange efficiency of the heat exchanger.

[0021] In this embodiment, by adding a fan to the indoor unit, the indoor air can be actively driven to flow through the heat exchanger, thereby enhancing the heat exchange efficiency of the heat exchanger. The introduction of the fan can not only improve the contact efficiency between the air and the heat exchanger surface, but also adapt the refrigerant flow regulation of the expansion valve by adjusting the wind speed under different operating conditions, so as to achieve a dynamic balance of heat exchange between the refrigerant side and the air side. Compared with the passive heat exchange method, this embodiment can significantly improve the cooling and heating efficiency of the indoor unit, optimize the overall performance of the air conditioner, and further enhance the accuracy and comfort of indoor temperature regulation.

[0022] In some embodiments, the first type of temperature values ​​includes the heat exchanger inlet pipe temperature and the heat exchanger outlet pipe temperature; the second type of temperature values ​​includes the indoor return air temperature and the indoor outlet air temperature; the temperature detection device includes: A heat exchanger inlet pipe temperature detection module, which is used to detect the heat exchanger inlet pipe temperature; A heat exchanger outlet pipe temperature detection module, which is used to detect the heat exchanger outlet pipe temperature; Indoor return air temperature detection module, which is used to detect the indoor return air temperature; The indoor air outlet temperature detection module is used to detect the indoor air outlet temperature.

[0023] Specifically, the heat exchanger inlet pipe temperature detection module can be used to detect the temperature of the refrigerant before entering the heat exchanger, characterize the initial state of the refrigerant when entering the heat exchanger, and serve as a starting reference for judging the degree of heat exchange of the refrigerant. The heat exchanger inlet pipe temperature detection module can use a temperature sensor (thermistor sensor or platinum resistance sensor). The heat exchanger inlet pipe temperature detection module can be installed on the outer wall of the refrigerant inlet pipe of the heat exchanger, close to the outer surface of the pipe, or directly embedded in the refrigerant pipeline, so as to monitor the inlet temperature of the refrigerant in real time.

[0024] The heat exchanger outlet pipe temperature detection module is used to detect the temperature of the refrigerant after it flows out of the heat exchanger, characterize the state change of the refrigerant after passing through the heat exchanger, and is used to calculate the degree of heat exchange on the refrigerant side. The module can also use high-sensitivity temperature sensors such as thermistors and platinum resistors. The module can be installed on the outer wall of the refrigerant outlet pipe of the heat exchanger, close to the outer surface of the pipe, or embedded in the refrigerant pipeline to ensure accurate measurement of the refrigerant outlet temperature.

[0025] The indoor return air temperature detection module is used to detect the temperature of the air returning from the indoor environment to the indoor unit, reflecting the temperature condition of the overall indoor environment as a parameter characterizing the indoor heat load. The module can use an air temperature sensor (a semiconductor temperature sensor or an infrared temperature sensor). The module can be installed near the return air outlet of the indoor unit and directly exposed to the return air to ensure that the real temperature of the indoor air can be detected in real time.

[0026] The indoor air outlet temperature detection module is used to detect the temperature of the air sent into the room after passing through the heat exchanger, characterizes the result of the heat exchange of the air by the heat exchanger, and is used to calculate the heat exchange efficiency of the air side. The module can also use an air temperature sensor. The module can be installed near the air outlet of the indoor unit, directly in the air supply channel, to ensure real-time collection of air supply temperature data.

[0027] In this embodiment, by setting a temperature detection device to detect the first type of temperature value (heat exchanger inlet pipe temperature and heat exchanger outlet pipe temperature) and the second type of temperature value (indoor return air temperature and indoor outlet air temperature), the heat exchange state of the refrigerant side and the indoor air side of the heat exchanger can be accurately sensed. The difference between the heat exchanger inlet pipe temperature and the outlet pipe temperature can reflect the degree of heat exchange of the refrigerant in the heat exchanger in real time; the difference between the indoor return air temperature and the outlet air temperature can dynamically characterize the heat exchange efficiency of the indoor air after passing through the heat exchanger. Such a multi-parameter detection mechanism significantly enhances the comprehensive perception of the air-conditioning operation state and provides an accurate basis for the controller to accurately adjust the expansion valve opening. Compared with the traditional method that relies only on a single temperature parameter, this embodiment can more finely control the refrigerant flow rate and the operating efficiency of the heat exchanger, thereby improving the energy efficiency of the air-conditioning system and the comfort of the indoor environment.

[0028] like Figure 3 As shown, this embodiment provides a control method for an indoor unit, wherein the indoor unit is applied to an air conditioner without communication between the indoor unit and the outdoor unit. The control method may be executed by a controller in the indoor unit, and the method may include: Step S12: During the operation of the indoor unit, obtain a first temperature value and a second temperature value; wherein the first temperature value is a temperature value used to characterize the heat exchange state on the refrigerant side of the heat exchanger, and the second temperature value is a temperature value used to characterize the heat exchange state on the indoor air side of the indoor unit.

[0029] In this embodiment, the first type of temperature values ​​includes the heat exchanger inlet pipe temperature and the heat exchanger outlet pipe temperature.

[0030] In this embodiment, the second type of temperature values ​​includes indoor return air temperature and indoor outlet air temperature.

[0031] In this embodiment, the controller can issue instructions to the preset heat exchanger inlet pipe temperature detection module, heat exchanger outlet pipe temperature detection module, indoor return air temperature detection module and indoor outlet air temperature detection module to respectively obtain the heat exchanger inlet pipe temperature, heat exchanger outlet pipe temperature, indoor return air temperature and indoor outlet air temperature.

[0032] Specifically, the heat exchanger inlet pipe temperature detection module can be used to detect the temperature of the refrigerant before entering the heat exchanger, characterize the initial state of the refrigerant when entering the heat exchanger, and serve as a starting reference for judging the degree of heat exchange of the refrigerant. The heat exchanger inlet pipe temperature detection module can use a temperature sensor (thermistor sensor or platinum resistance sensor). The heat exchanger inlet pipe temperature detection module can be installed on the outer wall of the refrigerant inlet pipe of the heat exchanger, close to the outer surface of the pipe, or directly embedded in the refrigerant pipeline, so as to monitor the inlet temperature of the refrigerant in real time.

[0033] The heat exchanger outlet pipe temperature detection module is used to detect the temperature of the refrigerant after it flows out of the heat exchanger, characterize the state change of the refrigerant after passing through the heat exchanger, and is used to calculate the degree of heat exchange on the refrigerant side. The module can also use high-sensitivity temperature sensors such as thermistors and platinum resistors. The module can be installed on the outer wall of the refrigerant outlet pipe of the heat exchanger, close to the outer surface of the pipe, or embedded in the refrigerant pipeline to ensure accurate measurement of the refrigerant outlet temperature.

[0034] The indoor return air temperature detection module is used to detect the temperature of the air returning from the indoor environment to the indoor unit, reflecting the temperature condition of the overall indoor environment as a parameter characterizing the indoor heat load. The module can use an air temperature sensor (a semiconductor temperature sensor or an infrared temperature sensor). The module can be installed near the return air outlet of the indoor unit and directly exposed to the return air to ensure that the real temperature of the indoor air can be detected in real time.

[0035] The indoor air outlet temperature detection module is used to detect the temperature of the air sent into the room after passing through the heat exchanger, characterizes the result of the heat exchange of the air by the heat exchanger, and is used to calculate the heat exchange efficiency of the air side. The module can also use an air temperature sensor. The module can be installed near the air outlet of the indoor unit, directly in the air supply channel, to ensure real-time collection of air supply temperature data.

[0036] Step S14: Based on the first temperature value and the second temperature value, control the opening of the expansion valve to adjust the flow rate of the refrigerant flowing into the heat exchanger.

[0037] In this embodiment, the step of controlling the opening of the expansion valve based on the first temperature value and the second temperature value to adjust the flow rate of the refrigerant flowing into the heat exchanger may include: First, the controller determines the working state of the compressor in the outdoor unit based on the first temperature value and the second temperature value.

[0038] For example, if the controller detects T inlet (heat exchanger inlet temperature) ≥ T return (indoor return air temperature) -3 for 20 seconds in a row, the outdoor unit compressor is judged to be in the stopped state. For another example, if the controller detects T inlet (heat exchanger inlet temperature) ≤ T return (indoor return air temperature) -5 for 20 seconds in a row, the outdoor unit compressor is judged to be in the started state.

[0039] Then, the controller determines a current startup cycle of the compressor when the working state of the compressor in the outdoor unit is startup.

[0040] For example, the controller can obtain the most recent start and stop records of the compressor by querying the operation database built into the indoor unit, thereby determining the current start cycle of the compressor.

[0041] Next, when the startup cycle is the Nth time, the controller determines the refrigerant heat exchange degree parameter of the heat exchanger based on the first type of temperature value, and determines the air heat exchange efficiency parameter of the indoor unit based on the second type of temperature value; wherein N is a positive integer greater than or equal to 2; wherein the refrigerant heat exchange degree parameter is a parameter indicating the heat exchange degree of the refrigerant in the heat exchanger, and the air heat exchange efficiency parameter is a parameter indicating the heat exchange efficiency of the air when flowing through the indoor unit.

[0042] Finally, the controller controls the opening of the expansion valve based on the refrigerant heat exchange degree parameter and the air heat exchange efficiency parameter to adjust the flow rate of the refrigerant flowing into the heat exchanger.

[0043] Correspondingly, if the startup cycle is the first time, the controller determines the refrigerant heat exchange degree parameter of the heat exchanger based on the first type of temperature value; and then controls the opening of the expansion valve based on the refrigerant heat exchange degree parameter to adjust the flow rate of the refrigerant flowing into the heat exchanger.

[0044] This embodiment uses a control method to obtain the first type of temperature value (characterizing the heat exchange state on the refrigerant side of the heat exchanger) and the second type of temperature value (characterizing the heat exchange state on the indoor air side of the indoor unit) in real time during the operation of the indoor unit, and dynamically controls the opening of the expansion valve based on these two types of temperature values, thereby accurately adjusting the refrigerant flow rate flowing into the heat exchanger. Compared with the prior art that only relies on a single temperature parameter or a fixed control strategy, this embodiment can achieve comprehensive perception and linkage control of the heat exchange state on the refrigerant side and the air side, overcoming the technical problem of inaccurate refrigerant flow control in non-communication air conditioners. In the absence of communication between the indoor unit and the outdoor unit, this method significantly improves the accuracy of expansion valve control, optimizes the dynamic matching of refrigerant flow, improves heat exchange efficiency and the overall operating performance of the air conditioning system, and further improves the comfort of the indoor environment.

[0045] In some embodiments, the step of controlling the opening of the expansion valve based on the first temperature value and the second temperature value to adjust the flow rate of the refrigerant flowing into the heat exchanger includes: Step S142: Based on the first temperature value and the second temperature value, determine the working state of the compressor in the outdoor unit.

[0046] For example, if the controller detects T inlet (heat exchanger inlet temperature) ≥ T return (indoor return air temperature) -3 for 20 seconds in a row, the outdoor unit compressor is judged to be in the stopped state. For another example, if the controller detects T inlet (heat exchanger inlet temperature) ≤ T return (indoor return air temperature) -5 for 20 seconds in a row, the outdoor unit compressor is judged to be in the started state.

[0047] Step S144: When the working state of the compressor in the outdoor unit is startup, determine the startup cycle of the current compressor.

[0048] For example, the controller can obtain the most recent start and stop records of the compressor by querying the operation database built into the indoor unit, thereby determining the current start cycle of the compressor.

[0049] Step S146: When the startup cycle is the Nth time, the refrigerant heat exchange degree parameter of the heat exchanger is determined based on the first temperature value, and the air heat exchange efficiency parameter of the indoor unit is determined based on the second temperature value; wherein N is a positive integer greater than or equal to 2; wherein the refrigerant heat exchange degree parameter is a parameter indicating the heat exchange degree of the refrigerant in the heat exchanger, and the air heat exchange efficiency parameter is a parameter indicating the heat exchange efficiency of the air when flowing through the indoor unit.

[0050] Specifically, in this embodiment, the controller can determine the refrigerant heat exchange degree parameter of the heat exchanger based on the first temperature value, and determine the air heat exchange efficiency parameter of the indoor unit based on the second temperature value in the following manner: First, the controller subtracts the heat exchanger inlet temperature from the heat exchanger outlet temperature to obtain the refrigerant heat exchange degree parameter; Then, the controller subtracts the indoor air outlet temperature from the indoor return air temperature to obtain the air heat exchange efficiency parameter.

[0051] Step S148: Based on the refrigerant heat exchange degree parameter and the air heat exchange efficiency parameter, control the opening of the expansion valve to adjust the flow rate of the refrigerant flowing into the heat exchanger.

[0052] Specifically, in this embodiment, the controller can control the opening of the expansion valve based on the refrigerant heat exchange degree parameter and the air heat exchange efficiency parameter in the following manner to adjust the flow rate of the refrigerant flowing into the heat exchanger: First, the controller determines the numerical range to which the refrigerant heat exchange degree parameter belongs.

[0053] Then, when the refrigerant heat exchange degree parameter is less than a preset lower limit value, the controller controls the expansion valve to reduce the opening degree periodically and in a first preset step; wherein the first preset step is proportional to the absolute value of the refrigerant heat exchange degree parameter.

[0054] Next, when the refrigerant heat exchange degree parameter is greater than or equal to a first preset upper limit value, the controller controls the expansion valve to increase the opening degree periodically and in a first preset step size.

[0055] Finally, when the refrigerant heat exchange degree parameter is greater than or equal to the preset lower limit value and less than the first preset upper limit value, the controller controls the opening of the expansion valve according to the air heat exchange efficiency parameter to adjust the flow rate of the refrigerant flowing into the heat exchanger.

[0056] This embodiment solves the technical problem of inaccurate refrigerant flow control when there is no communication between the indoor unit and the outdoor unit by controlling the opening of the expansion valve based on the first temperature value and the second temperature value. Specifically, by judging the working state of the compressor (start or stop) in real time, the startup cycle of the current compressor is determined, and in the Nth startup cycle, the refrigerant heat exchange degree parameter of the heat exchanger is calculated based on the first temperature value, and the indoor air heat exchange efficiency parameter is calculated based on the second temperature value. By combining the heat exchange information on the refrigerant side and the air side, the opening of the expansion valve is dynamically adjusted, so that the refrigerant flow and heat exchange demand can be accurately matched. Compared with the traditional method that relies only on a single temperature value or a fixed adjustment strategy, this embodiment significantly improves the heat exchange efficiency of the heat exchanger and the overall performance of the air-conditioning system, and further optimizes the comfort of the indoor environment and the energy efficiency ratio of the system.

[0057] like Figure 4 As shown, in some embodiments, the first type of temperature value includes the heat exchanger inlet pipe temperature and the heat exchanger outlet pipe temperature; the second type of temperature value includes the indoor return air temperature and the indoor outlet air temperature; the step of determining the heat exchange degree parameter of the heat exchanger based on the first type of temperature value, and determining the air heat exchange efficiency parameter of the indoor unit based on the second type of temperature value, includes: Step S1462: Subtract the heat exchanger inlet temperature from the heat exchanger outlet temperature to obtain the refrigerant heat exchange degree parameter.

[0058] Step S1464: Subtract the indoor air outlet temperature from the indoor return air temperature to obtain the air heat exchange efficiency parameter.

[0059] This embodiment further improves the indoor unit's ability to perceive the heat exchange state comprehensively by introducing the heat exchanger inlet and outlet temperatures, indoor return air temperature and outlet air temperature, respectively, to calculate the refrigerant heat exchange degree parameters and air heat exchange efficiency parameters. Specifically, by subtracting the heat exchanger outlet temperature from the inlet temperature, the heat exchange degree of the refrigerant in the heat exchanger is accurately reflected; by subtracting the indoor return air temperature from the outlet air temperature, the heat exchange efficiency of the indoor air after passing through the heat exchanger is intuitively characterized. This method not only realizes the accurate calculation of the heat exchange state of the refrigerant side and the air side, but also provides multi-dimensional key data support for the subsequent dynamic adjustment of the expansion valve opening. Compared with the traditional single temperature monitoring method, this embodiment can more comprehensively and accurately match the refrigerant flow rate with the system heat exchange requirements, thereby improving the operating efficiency of the air conditioner and the comfort of indoor temperature regulation.

[0060] In some embodiments, the step of controlling the opening of the expansion valve based on the refrigerant heat exchange degree parameter and the air heat exchange efficiency parameter to adjust the flow rate of the refrigerant flowing into the heat exchanger includes: Step S1482: Determine the numerical range to which the refrigerant heat exchange degree parameter belongs.

[0061] Specifically, the controller determines the numerical range to which the refrigerant heat exchange degree parameter belongs according to the value thereof. The refrigerant heat exchange degree parameter is calculated by the difference between the outlet temperature and the inlet temperature of the heat exchanger and is used to characterize the degree of heat exchange completed by the refrigerant in the heat exchanger.

[0062] When the refrigerant heat exchange degree parameter is in the low range (less than the preset lower limit), it means that the refrigerant has not evaporated sufficiently and liquid return may occur.

[0063] When the refrigerant heat exchange degree parameter belongs to the high range (greater than or equal to the first preset upper limit value), it means that the refrigerant is overheated and the refrigerant flow may be insufficient.

[0064] When the refrigerant heat exchange degree parameter is in the normal range (between the lower limit and the upper limit), it means that the refrigerant heat exchange is normal. At this time, it needs to be further optimized in combination with the air heat exchange efficiency parameter.

[0065] Step S1484: When the refrigerant heat exchange degree parameter is less than a preset lower limit value, the expansion valve is controlled to reduce the opening periodically and in a first preset step size; wherein the first preset step size is proportional to the absolute value of the refrigerant heat exchange degree parameter.

[0066] Specifically, if the refrigerant heat exchange degree parameter is lower than the preset lower limit, it indicates that the refrigerant has not completely evaporated in the heat exchanger, and there may be a refrigerant liquid return problem. To solve this problem, the controller periodically reduces the opening of the expansion valve, thereby reducing the refrigerant flow rate flowing into the heat exchanger and improving the evaporation effect of the refrigerant.

[0067] More specifically, the opening of the expansion valve is reduced at regular intervals (e.g., 20 seconds), and the size of the reduction step (i.e., the first preset step) is proportional to the absolute value of the refrigerant heat exchange degree parameter, i.e., the lower the refrigerant heat exchange degree, the larger the step, and the more obvious the adjustment amplitude.

[0068] In this implementation, the preset lower limit value may be 0° C., and the first preset step size may be 2×|ΔTout-in|.

[0069] Step S1486: When the refrigerant heat exchange degree parameter is greater than or equal to a first preset upper limit value, the expansion valve is controlled to increase the opening periodically and in a first preset step size.

[0070] Specifically, if the refrigerant heat exchange degree parameter exceeds or is equal to the first preset upper limit value, it indicates that the refrigerant heat exchange is too strong, and the refrigerant may be overheated due to insufficient refrigerant flow into the heat exchanger. To solve this problem, the controller periodically increases the opening of the expansion valve, thereby increasing the refrigerant flow and reducing the refrigerant temperature.

[0071] More specifically, the opening of the expansion valve is increased at regular intervals (e.g., 20 seconds), and the size of the increased step (i.e., the first preset step) is proportional to the absolute value of the refrigerant heat exchange degree parameter, i.e., the higher the heat exchange degree, the larger the step, and the more obvious the adjustment amplitude.

[0072] Step S1488: When the refrigerant heat exchange degree parameter is greater than or equal to the preset lower limit value and less than the first preset upper limit value, the opening of the expansion valve is controlled according to the air heat exchange efficiency parameter to adjust the flow rate of the refrigerant flowing into the heat exchanger.

[0073] Specifically, when the refrigerant heat exchange degree parameter is in the normal range (between the preset lower limit and upper limit), it means that the heat exchange on the refrigerant side is in a normal state, but in order to further optimize the operating efficiency of the entire air-conditioning system, it is necessary to make precise adjustments in combination with the heat exchange efficiency parameters on the air side.

[0074] For example, the air heat exchange efficiency parameter (calculated by the difference between the indoor return air temperature and the outlet air temperature) can be analyzed to determine the air side heat exchange state. Then the opening of the expansion valve can be dynamically adjusted to match the refrigerant flow with the air side heat exchange demand, achieving a balance between the refrigerant and air side heat exchange.

[0075] In a specific embodiment, the preset lower limit value is a threshold value for judging insufficient heat exchange of the refrigerant, indicating the minimum heat exchange degree at which the refrigerant fails to fully evaporate in the heat exchanger. When the refrigerant heat exchange degree parameter (the difference between the outlet temperature of the heat exchanger and the inlet temperature) is lower than this value, there may be a situation where the refrigerant flow is too large or the heat load is insufficient, which may easily cause the problem of refrigerant liquid return. By setting the preset lower limit value, it is possible to detect whether the refrigerant heat exchange efficiency is lower than the normal working range, so as to take measures to reduce the opening of the expansion valve, thereby reducing the refrigerant flow into the heat exchanger and improving the refrigerant evaporation condition. The preset lower limit value can be 0°C.

[0076] In a specific embodiment, the first preset upper limit value is a threshold value for judging whether the refrigerant heat exchange is too strong, indicating the maximum heat exchange degree of the refrigerant absorbing too much heat in the heat exchanger. When the refrigerant heat exchange degree parameter (the difference between the heat exchanger outlet pipe temperature and the inlet pipe temperature) is greater than or equal to this value, there may be a situation where the refrigerant flow is too small or the heat load is too high, which can easily lead to the problem of refrigerant overheating. By setting the first preset upper limit value, it is possible to detect whether the refrigerant heat exchange exceeds the normal working range, so as to take measures to increase the opening of the expansion valve, thereby increasing the refrigerant flow into the heat exchanger and reducing the risk of refrigerant overheating. The first preset upper limit value can be 5°C.

[0077] In a specific embodiment, the preset lower limit value may be a value within the range of -2°C to 0°C.

[0078] In a specific embodiment, the first preset upper limit value may be a value within the range of 4°C to 6°C.

[0079] In a specific embodiment, the first preset step size represents the single change amplitude (increase or decrease amount) of the expansion valve opening during the adjustment process. It can be used to dynamically control the increase and decrease rate of the expansion valve opening to ensure the stability and accuracy of the adjustment. When the refrigerant heat exchange is insufficient (the refrigerant heat exchange degree parameter is less than the preset lower limit value), the expansion valve opening is reduced according to the first preset step size. When the refrigerant heat exchange is too strong (the refrigerant heat exchange degree parameter is greater than or equal to the first preset upper limit value), the expansion valve opening is increased according to the first preset step size. The size of the first preset step size can be dynamically adjusted according to the degree of deviation of the refrigerant heat exchange degree parameter from the preset value. The greater the deviation, the larger the step size to speed up the adjustment speed; the smaller the deviation, the smaller the step size to avoid over-adjustment.

[0080] This embodiment realizes precise regulation of the refrigerant flow rate flowing into the heat exchanger by dynamically controlling the opening of the expansion valve in different intervals based on comprehensive analysis of the refrigerant heat exchange degree parameter and the air heat exchange efficiency parameter. Specifically, firstly, by judging the numerical interval to which the refrigerant heat exchange degree parameter belongs, corresponding control strategies are adopted for different intervals: when the refrigerant heat exchange is insufficient (the parameter is less than the preset lower limit), the refrigerant flow rate is reduced by periodically reducing the opening of the expansion valve to avoid the refrigerant liquid return problem; when the refrigerant heat exchange is too strong (the parameter is greater than or equal to the first preset upper limit), the refrigerant flow rate is increased by periodically increasing the opening of the expansion valve to avoid refrigerant overheating; when the parameter is in the normal range (greater than or equal to the lower limit but less than the upper limit), the expansion valve opening is dynamically adjusted in combination with the air heat exchange efficiency parameter to achieve the best match of heat exchange between the refrigerant side and the air side. This method makes full use of the multi-dimensional heat exchange information on the refrigerant and air sides, avoids the refrigerant flow mismatch problem caused by single parameter control in traditional methods, and significantly improves the operating efficiency, heat exchange performance and indoor environment comfort of the air conditioner.

[0081] In some embodiments, when the refrigerant heat exchange degree parameter is greater than or equal to the preset lower limit value and less than the first preset upper limit value, the step of controlling the opening of the expansion valve according to the air heat exchange efficiency parameter to adjust the flow rate of the refrigerant flowing into the heat exchanger includes: Step S14882: Determine the numerical range to which the air heat exchange efficiency parameter belongs.

[0082] Specifically, the controller determines the numerical range to which the current value of the air heat exchange efficiency parameter belongs by analyzing the current value of the air heat exchange efficiency parameter. The air heat exchange efficiency parameter is calculated by the difference between the indoor return air temperature and the outlet air temperature, and represents the heat exchange effect of the indoor air passing through the heat exchanger.

[0083] More specifically, when the air heat exchange efficiency parameter belongs to a low range (less than the lower limit of the air heat exchange efficiency), it indicates that the air heat exchange efficiency is insufficient, which may be due to insufficient refrigerant flow causing the heat exchanger to be unable to meet the current indoor air load demand.

[0084] When the air heat exchange efficiency parameter is within the normal range (greater than or equal to the lower limit but less than the upper limit), it indicates that the air heat exchange efficiency is normal and there is no need to adjust the expansion valve opening.

[0085] When the air heat exchange efficiency parameter is in the high range (greater than or equal to the upper limit of the air heat exchange efficiency), it indicates that the air heat exchange efficiency is too high. It may be that the excessive refrigerant flow causes the heat exchanger to exceed the load demand.

[0086] Step S14884: When the air heat exchange efficiency parameter is less than the preset lower limit value of the air heat exchange efficiency, the expansion valve is controlled to increase the opening periodically and in a second preset step; wherein the lower limit value of the air heat exchange efficiency is the air heat exchange efficiency target value minus the first deviation range; wherein the second preset step is proportional to the absolute value of the difference between the air heat exchange efficiency parameter and the air heat exchange efficiency target value.

[0087] For example, the second preset step size may be 2×|ΔTwind−ΔTwindtarget|.

[0088] Specifically, if the air heat exchange efficiency parameter is lower than the lower limit of the target value (i.e., the target value minus the first deviation range), it means that the heat exchange efficiency on the air side is insufficient, and it may be that the refrigerant flow is too low, causing the heat exchanger to be unable to meet the current air load demand. In this case, the controller periodically increases the opening of the expansion valve to increase the refrigerant flow into the heat exchanger, thereby improving the heat exchange efficiency on the air side.

[0089] More specifically, the expansion valve opening increases by a certain amount every certain period (such as 20 seconds). The increase (second preset step) is proportional to the absolute value of the difference between the air heat exchange efficiency parameter and the target value, that is, the greater the deviation, the greater the step.

[0090] Step S14886: When the air heat exchange efficiency parameter is greater than or equal to the preset lower limit value of the air heat exchange efficiency and less than the preset upper limit value of the air heat exchange efficiency, control the expansion valve to maintain the current opening; wherein the preset upper limit value of the air heat exchange efficiency is the air heat exchange efficiency target value plus the first deviation range.

[0091] Specifically, if the air heat exchange efficiency parameter is within the upper and lower deviation range of the target value (i.e. greater than or equal to the lower limit and less than the upper limit), it means that the air side heat exchange efficiency is in a normal state, and there is no need to adjust the opening of the expansion valve. The controller will maintain the current opening to maintain the stability of the system operation.

[0092] Step S14888: When the air heat exchange efficiency parameter is greater than or equal to the preset upper limit of the air heat exchange efficiency, the expansion valve is controlled to reduce the opening periodically and in a second preset step size.

[0093] Specifically, if the air heat exchange efficiency parameter is higher than the upper limit of the target value (i.e., the target value plus the first deviation range), it means that the air side heat exchange efficiency is too high, which may be due to excessive refrigerant flow, causing the heat exchanger to exceed the load demand. In this case, the controller reduces the air side heat exchange efficiency by periodically reducing the opening of the expansion valve to reduce the refrigerant flow into the heat exchanger.

[0094] More specifically, the expansion valve opening is reduced by a certain amount every certain period, and the reduction amount (second preset step length) is proportional to the absolute value of the difference between the air heat exchange efficiency parameter and the target value, that is, the greater the deviation, the greater the step length.

[0095] In a specific embodiment, the second preset step size is proportional to the absolute value of the difference between the air heat exchange efficiency parameter and the air heat exchange efficiency target value. When the difference is large, the step size is increased to make the adjustment faster. When the difference is small, the step size is reduced to avoid system oscillation.

[0096] In a specific embodiment, the first deviation range can be used to determine the upper and lower limit value range of the air heat exchange efficiency parameter. Through the first deviation range, a target interval can be dynamically defined to indicate whether the current air heat exchange efficiency parameter is close to the target value, thereby determining whether the expansion valve opening is increased, decreased, or maintained unchanged. For example: upper limit value = air heat exchange efficiency target value + first deviation range, lower limit value = air heat exchange efficiency target value - first deviation range. The first deviation range can be 5% or 10% of the air heat exchange efficiency target value.

[0097] This embodiment achieves dynamic matching between the refrigerant flow rate and the air side heat exchange demand by further accurately adjusting the opening of the expansion valve based on the air heat exchange efficiency parameter in the normal range when the refrigerant heat exchange degree parameter is in the normal range. Specifically, when the air heat exchange efficiency parameter is lower than the lower limit of the target value (the target value minus the deviation range), the refrigerant flow rate is increased and the air heat exchange efficiency is improved by periodically increasing the opening of the expansion valve; when the air heat exchange efficiency parameter is within the upper and lower deviation range of the target value, the opening of the expansion valve is maintained to maintain the stable operation of the system; when the air heat exchange efficiency parameter is higher than the upper limit of the target value (the target value plus the deviation range), the refrigerant flow rate is reduced by periodically reducing the opening of the expansion valve to avoid energy waste. By adopting a dynamic adjustment mechanism in which the second preset step size is proportional to the absolute value of the deviation of the air heat exchange efficiency parameter, this embodiment can effectively adapt to the changes in different indoor loads and environmental conditions, and significantly improve the heat exchange efficiency, energy-saving performance and comfort of the air conditioner indoor environment.

[0098] In some embodiments, the method further comprises: After the Nth startup cycle ends, the duration of the Nth startup cycle is determined.

[0099] Specifically, after the Nth startup cycle of the compressor is completed, the controller counts and records the duration of the startup cycle (ie, the time from when the compressor starts to stop running).

[0100] Determine a numerical interval of the duration of the Nth startup cycle.

[0101] Specifically, the duration of the Nth start-up cycle obtained by statistics is compared with the preset time interval range to determine its specific numerical range. It can be understood that the division of time intervals helps to dynamically identify the current operating status and regulation efficiency of the air conditioner. If the duration is less than the lower limit, it indicates that the refrigerant flow may be too large; if it is in a reasonable range (between the lower limit and the upper limit), it indicates that the system regulation is relatively stable; if the duration is greater than the upper limit, it may indicate that the refrigerant flow is insufficient.

[0102] More specifically, if the duration of the Nth startup cycle is less than the lower limit, it indicates that there may be an oversupply of refrigerant. If the current duration is within the upper and lower limits, it indicates that the system is operating relatively normally. If the current duration exceeds the upper limit, it may indicate that the refrigerant flow is insufficient, resulting in low temperature regulation efficiency.

[0103] When the numerical interval of the duration of the Nth startup cycle is less than the preset time lower limit, the air heat exchange efficiency target value is reduced by the first adjustment amount; wherein the preset time lower limit is the duration of the N-1th startup cycle minus the second deviation range.

[0104] Specifically, when it is determined that the duration of the Nth startup cycle falls within an interval less than the lower limit of the time, the controller will reduce the target value of the air heat exchange efficiency by the first adjustment amount (larger adjustment amount). It is understandable that if the startup cycle is too short, it means that the refrigerant supply of the system is relatively too large, and the compressor is frequently turned on and off, resulting in a decrease in system efficiency, increased energy consumption and possible impact on the life of the compressor. Therefore, since the problem is more serious, a larger adjustment amount is selected to quickly reduce the target value of the air heat exchange efficiency, thereby reducing the refrigerant flow and extending the compressor startup cycle.

[0105] When the numerical interval of the duration of the Nth startup cycle is greater than the preset lower time limit and less than the preset upper time limit, the air heat exchange efficiency target value is reduced by a second adjustment amount; wherein the preset upper time limit is the duration of the N-1th startup cycle plus a second deviation range; wherein the second adjustment amount is lower than the first adjustment amount.

[0106] Specifically, when it is determined that the duration of the Nth startup cycle is within a reasonable range (between the lower limit and the upper limit), the controller will appropriately reduce the target value of the air heat exchange efficiency by the second adjustment amount (a smaller adjustment amount). It can be understood that in this numerical range, the system runs relatively smoothly, and only a small amount of dynamic optimization is required to fine-tune the refrigerant flow. Because the current system operation state is close to normal, only a small adjustment of the target value is required to improve the system efficiency, so a smaller adjustment amount is selected for adjustment.

[0107] When the numerical interval of the duration of the Nth startup cycle is greater than the preset time upper limit, the current air heat exchange efficiency target value is maintained unchanged.

[0108] Specifically, if the startup cycle lasts for a long time, it means that the refrigerant flow is insufficient and the system is running for a long time to achieve the expected cooling effect. In this case, further reducing the target value may cause the refrigerant flow to decrease further, making the problem worse. Therefore, keep the current target value unchanged to avoid misadjustment.

[0109] This embodiment realizes intelligent refrigerant flow control optimization by dynamically adjusting the target value of air heat exchange efficiency according to the numerical interval of its duration after each compressor startup cycle. Specifically, when the startup cycle duration is too short, the air heat exchange efficiency target value is reduced by a larger first adjustment amount to quickly reduce the system's refrigerant flow, thereby avoiding the system's operating efficiency being reduced or wasting energy due to excessive refrigerant supply. When the startup cycle duration is within a reasonable range, the target value adjustment is refined by a smaller second adjustment amount to further improve the accuracy of the adjustment and the operating balance of the system. When the startup cycle duration is long, keeping the current target value unchanged helps maintain the efficient operation of the system in a stable state. On the whole, this method improves the energy-saving effect, comfort and operating stability of the air conditioner by dynamically adjusting the target value to respond to changes in the system's operating state, and overcomes the problems of lag or inflexibility in adjustment in related technologies.

[0110] In a specific embodiment, the first adjustment amount is a relatively large adjustment amount for quickly reducing the target value of the air heat exchange efficiency when it is detected that the duration of the startup cycle is less than the preset time lower limit. For example, assuming that the target value of the air heat exchange efficiency is initially 90%, the first adjustment amount may be a reduction of 5%-10%.

[0111] In a specific embodiment, the second adjustment amount is a smaller adjustment amount for fine-tuning the target value of air heat exchange efficiency when it is detected that the duration of the startup cycle is between the preset lower limit and upper limit of the time. For example, assuming that the target value of air heat exchange efficiency is initially 90%, the second adjustment amount may be a decrease of 2%-3%.

[0112] In a specific embodiment, the second deviation range is a tolerance range for judging the degree of deviation between the duration of the startup cycle and the duration of the previous startup cycle. It defines the width of the lower and upper time limits, and is used to divide the numerical interval of the duration. It is understandable that the second deviation range is used to dynamically evaluate the difference between the current startup cycle and the previous cycle, and by limiting the tolerance range of the upper and lower limits, frequent adjustments caused by small periodic fluctuations are avoided, while adapting to normal changes in system operation. For example, assuming that the duration of the N-1th startup cycle is 300 seconds, the second deviation range can be set to 50 seconds.

[0113] In some embodiments, the method further comprises: In the case where the startup cycle is the first time, determining a refrigerant heat exchange degree parameter of the heat exchanger based on the first type of temperature value; Based on the refrigerant heat exchange degree parameter, the opening of the expansion valve is controlled to adjust the flow rate of the refrigerant flowing into the heat exchanger.

[0114] In this embodiment, by determining the refrigerant heat exchange degree parameter of the heat exchanger based on the first type of temperature value (such as the heat exchanger inlet pipe temperature and the heat exchanger outlet pipe temperature) when the startup cycle is the first time, an accurate evaluation of the heat exchange characteristics of the refrigerant in the heat exchanger can be achieved. On this basis, by controlling the opening of the expansion valve, the refrigerant flow rate flowing into the heat exchanger is accurately adjusted, thereby optimizing the working efficiency of the heat exchanger. This method can quickly establish a reasonable refrigerant flow control mechanism when the compressor is started for the first time, avoiding the problem of low efficiency or excessive energy consumption caused by the reliance on experience values ​​for refrigerant flow regulation during the first startup in the prior art, thereby improving the operating efficiency of the air-conditioning system, reducing energy waste, and improving the response speed and accuracy of indoor temperature control.

[0115] In some embodiments, the step of controlling the opening of the expansion valve based on the refrigerant heat exchange degree parameter to adjust the flow rate of the refrigerant flowing into the heat exchanger includes: Determine the numerical range to which the refrigerant heat exchange degree parameter belongs.

[0116] When the refrigerant heat exchange degree parameter is less than a preset lower limit value, controlling the expansion valve to reduce the opening degree periodically and in a first preset step length; wherein the first preset step length is proportional to the absolute value of the refrigerant heat exchange degree parameter; When the refrigerant heat exchange degree parameter is greater than or equal to a second preset upper limit value, controlling the expansion valve to increase the opening degree periodically and in a first preset step; wherein the second preset upper limit value is less than the first preset upper limit value; When the refrigerant heat exchange degree parameter is greater than or equal to the preset lower limit value and less than the second preset upper limit value, the expansion valve is controlled to maintain the current opening degree.

[0117] In this embodiment, the second preset upper limit value is a threshold value for limiting the refrigerant heat exchange degree parameter, which is lower than the first preset upper limit value and is used to more sensitively adjust the opening of the expansion valve when the startup cycle is the first time. The threshold value can respond to the change of the refrigerant heat exchange degree parameter earlier to prevent the refrigerant flow from being too large or too small to affect the stable operation of the system.

[0118] Specifically, the second preset upper limit value may be defined as an empirical parameter and may be set according to the operating performance and actual working conditions of the air conditioner. For example, for some air conditioners, the second preset upper limit value may be 2 (unit: °C), which, compared with the first preset upper limit value (e.g., 5 °C), is used to intervene in the adjustment process more quickly to reduce the low heat exchange efficiency or refrigerant waste caused by the late adjustment of the refrigerant.

[0119] In this embodiment, the problem of unstable refrigerant flow regulation during the first startup process is solved by accurately controlling the opening of the expansion valve based on the numerical range of the refrigerant heat exchange degree parameter when the startup cycle is the first time. When the refrigerant heat exchange degree parameter is less than the preset lower limit, the opening of the expansion valve is periodically reduced by a first preset step proportional to the absolute value of the parameter, thereby effectively reducing the refrigerant flow and avoiding energy waste and heat exchange efficiency reduction caused by excessive refrigerant; when the parameter is greater than or equal to the second preset upper limit, the expansion valve opening is periodically increased by the same first preset step to ensure that the refrigerant flow can meet the refrigeration demand. When the parameter is between the preset lower limit and the second preset upper limit, the opening of the expansion valve remains unchanged, thereby stabilizing the system operation and avoiding unnecessary fluctuations caused by too frequent adjustments. This method fully considers the dynamic characteristics of the refrigerant flow demand in the initial stage of the startup cycle, realizes more accurate refrigerant flow regulation, improves the startup efficiency and stability of the system, and lays the foundation for subsequent stable operation.

[0120] like Figure 5 and Figure 6 As shown, an air conditioner without communication between the indoor unit and the outdoor unit is provided. The indoor unit of the air-conditioned room may include components such as an electronic expansion valve, a heat exchanger, and a fan. To meet the parameter detection and control of the air-conditioning system, the system also includes an indoor return air temperature sensor, an indoor outlet air temperature sensor, an indoor heat exchanger inlet temperature sensor, and an indoor heat exchanger outlet temperature sensor. There is no communication between the indoor unit and the outdoor unit and the thermostat, only switch control, including fan switch and four-way valve switch signals.

[0121] Specifically, the outdoor unit may include: Compressor: Completes the core cooling / heating function of the air conditioner by driving the refrigerant circulation.

[0122] Condenser: It is used to convert the gaseous state of the refrigerant into liquid state in cooling mode and release heat at the same time; in heating mode, the condenser acts as an evaporator through reverse operation of the four-way valve.

[0123] Four-way valve: used to switch between cooling and heating modes and control the flow direction of the refrigerant. In different modes, the S, D, E, and C ports will change the connected pipelines.

[0124] External fan: used to drive outdoor air to flow through the condenser to improve heat exchange efficiency.

[0125] External unit throttle valve: used to adjust the pressure and flow of the refrigerant during operation to ensure that the refrigerant meets the heat exchange requirements when entering the next cycle.

[0126] Specifically, the indoor unit may include: Evaporator: In cooling mode, the refrigerant absorbs heat from the indoor air and vaporizes in the evaporator; in heating mode, the refrigerant releases heat.

[0127] Expansion valve: used to adjust the refrigerant flow and pressure entering the evaporator to ensure optimal heat exchange efficiency.

[0128] Indoor fan: drives indoor air through the evaporator to complete cooling or heating of the indoor air.

[0129] Temperature detection device: Inlet pipe temperature sensor: monitors the temperature of the refrigerant entering the evaporator and reflects the initial state of heat exchange of the refrigerant.

[0130] Outlet pipe temperature sensor: monitors the temperature of the refrigerant flowing out of the evaporator and reflects the final state of the refrigerant's heat exchange.

[0131] Indoor environment temperature sensor: monitors the indoor environment temperature and reflects the current indoor temperature conditions.

[0132] Outlet air temperature sensor: monitors the temperature of the air after being processed by the evaporator, reflecting the heat exchange effect on the indoor air side.

[0133] like Figure 6 The figure shows the control connection diagram of the unit. C is the common terminal, Y is the fan switch signal, B is the four-way valve signal, G is the fan signal, and * is other signals.

[0134] As a heat pump model, when the fan is on and the four-way valve is off, the indoor unit is controlled to operate in cooling mode; when the fan is on and the four-way valve is on, the indoor unit is controlled to operate in heating mode; when the fan is off and the four-way valve is off, the indoor unit is executed according to the shutdown command. When the fan is off and the four-way valve is on, the indoor unit determines that the control signal is abnormal and executes according to the shutdown command. If the thermostat does not have a four-way valve switch signal, the indoor unit is controlled as a single cooling machine, that is, the default four-way valve signal is off.

[0135] The electronic expansion valve is controlled as follows in different states: 1. Cooling mode Initial stage: In the initial stage of refrigeration startup (within 2 minutes after the fan is turned on), the initial opening of the electronic expansion valve is determined according to the indoor ambient temperature, as shown in the following table.

[0136] It can be understood that, taking the fully open electronic expansion valve of 480pls as an example, when the indoor ambient temperature is low, it is considered that the room load is small and the required cooling capacity is small, and the initial valve step is executed according to a smaller opening. When the indoor ambient temperature is high, it is considered that the room load is large and the required cooling capacity is large, and the initial valve step is executed according to a larger opening. According to different ranges of indoor ambient temperature, different initial opening values ​​are determined, and the electronic expansion valve is controlled more accurately to adjust the refrigerant circulation volume of the air-conditioning system to achieve better matching of room load and improve comfort.

[0137] Running process: After the fan is turned on and runs for 2 minutes, the opening of the electronic expansion valve is adjusted according to the following scheme.

[0138] 1) In the first start-stop cycle, determine the difference in inlet and outlet temperatures of the indoor heat exchanger and execute according to the following table: It can be understood that △Tout-in = Tout-Tin, Tout is the outlet temperature of the heat exchanger, and Tin is the inlet temperature of the heat exchanger. When calculating, Tout and Tin are the average values ​​calculated every 20 seconds.

[0139] △Tout-in < 0, indicating that the refrigerant in the heat exchanger cannot be completely evaporated, and there is a liquid return problem. To ensure the reliable operation of the air-conditioning system, it is necessary to reduce the opening of the electronic expansion valve and reduce the system refrigerant circulation volume. Similarly, when △Tout-in ≥ 2, it means that the heat exchanger has a certain degree of superheat and the system refrigerant circulation volume is low. It is necessary to increase the opening of the electronic expansion valve to increase the refrigerant circulation volume and prevent the heat exchanger from being overheated.

[0140] 2) Calculate △T wind target and △T return wind stop.

[0141] △Twind = Treturn air - Tout, Tout is the indoor outlet air temperature, Treturn air is the indoor return air temperature. When calculating, Treturn air and Tout are the average values ​​calculated every 20 seconds.

[0142] △T wind target is the target value of the return air temperature difference calculated during the compressor start-stop cycle based on the T return air value and the pipe temperature difference. The calculation method is as follows: If T inlet ≥ T return air - 3 is detected for 20 consecutive seconds, it is determined that the outdoor unit compressor is in the stopped state.

[0143] If T inlet ≤ T return air - 5 is detected for 20 consecutive seconds, it is determined that the outdoor unit compressor is in the on state.

[0144] In other cases, the previous judgment is maintained, and the first entry is judged as stopped state.

[0145] The start time is when the outdoor unit compressor is judged to be in the on state, and the end time is when the outdoor unit compressor is judged to be in the stopped state. The entire compressor on-off cycle time is recorded as t1.

[0146] It is understandable that in the cooling state, if the outdoor compressor has stopped and there is no refrigerant circulating in the pipeline, T inlet will be close to T return air, and the difference will decrease rapidly. The 5℃ and 3℃ temperature differences for judging the start and stop of the compressor are empirical values, and different models may have different values.

[0147] 3) In the second start-stop cycle, if T inlet ≤ T return air - 5 is detected for 20 consecutive seconds, the compressor is judged to be restarted. After that, the electronic expansion valve is controlled as follows: According to the temperature difference between the inlet and outlet pipes of the heat exchanger, the opening degree of the electronic expansion valve is calculated. At this time, the opening range is larger than the initial startup range. (At this time, it is 5°C, and the first time is 2°C. Increasing the difference range is to provide space for subsequent adjustment based on the temperature difference between the outlet and return air.) In the range of 0≤△Tout-in<5, adjust the opening of the electronic expansion valve according to the △T wind target: During the process, if Tinlet ≥ Treturn air - 3 is detected for 20 consecutive seconds, the compressor is judged to be stopped, and the difference between the stop time and the start time is recorded, which is recorded as t2.

[0148] If t2<t1-300, △T' wind target value = △T wind target-2; If t1-300≤t2<t1+300, △T' wind target value = △T wind target -1; If t2≥t1+300, △T wind target value = △T wind target.

[0149] The compressor start-stop cycle becomes shorter, the cooling capacity output is too large, and the refrigerant flow rate needs to be reduced, that is, the valve step is reduced; The compressor start and stop cycles are consistent, so the △T wind target value needs to be slightly adjusted. The compressor on-off cycle becomes longer, indicating that the cooling comfort has improved and the existing electronic expansion valve control can be maintained.

[0150] 2. Heating mode The electronic expansion valve is controlled according to the maximum opening. It is understandable that heating requires throttling in the outdoor unit, and the indoor unit is not throttled, and the electronic expansion valve is treated as fully open.

[0151] According to an embodiment of the present invention, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a computer, the computer executes the method described in any of the above embodiments.

[0152] According to an embodiment of the present invention, a computer program product including instructions is also provided. When the instructions are executed by a computer, the computer executes a method in any one of the above embodiments.

[0153] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0154] Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments, and this embodiment will not be described in detail here.

[0155] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0156] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0157] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. An indoor unit, characterized in that: The indoor unit is applied to an air conditioner without communication between the indoor unit and the outdoor unit, and the indoor unit at least comprises: A heat exchanger, which is used to perform heat exchange on the refrigerant flowing through it; An expansion valve, which is used to control the flow of refrigerant into the heat exchanger; A temperature detection device, which is used to detect a first type of temperature value and a second type of temperature value; wherein the first type of temperature value is a temperature value used to characterize the heat exchange state of the refrigerant side of the heat exchanger, and the second type of temperature value is a temperature value used to characterize the heat exchange state of the indoor air side of the indoor unit; A controller is used to control the opening of the expansion valve based on the first temperature value and the second temperature value to adjust the flow rate of the refrigerant flowing into the heat exchanger.

2. The indoor unit according to claim 1, characterized in that: The indoor unit further comprises: A fan is used to drive indoor air to flow through the heat exchanger to improve the heat exchange efficiency of the heat exchanger.

3. The indoor unit according to claim 1, characterized in that: The first type of temperature values ​​include the heat exchanger inlet pipe temperature and the heat exchanger outlet pipe temperature; the second type of temperature values ​​include the indoor return air temperature and the indoor outlet air temperature; the temperature detection device includes: A heat exchanger inlet pipe temperature detection module, which is used to detect the heat exchanger inlet pipe temperature; A heat exchanger outlet pipe temperature detection module, which is used to detect the heat exchanger outlet pipe temperature; Indoor return air temperature detection module, which is used to detect the indoor return air temperature; The indoor air outlet temperature detection module is used to detect the indoor air outlet temperature.

4. A control method for an indoor unit, characterized in that: The indoor unit is applied to an air conditioner without communication between the indoor unit and the outdoor unit, and the control method includes: During the operation of the indoor unit, a first temperature value and a second temperature value are obtained; wherein the first temperature value is a temperature value used to characterize the heat exchange state on the refrigerant side of the heat exchanger, and the second temperature value is a temperature value used to characterize the heat exchange state on the indoor air side of the indoor unit; Based on the first temperature value and the second temperature value, the opening of the expansion valve is controlled to adjust the flow rate of the refrigerant flowing into the heat exchanger.

5. The method according to claim 4, characterized in that The step of controlling the opening of the expansion valve based on the first temperature value and the second temperature value to adjust the flow rate of the refrigerant flowing into the heat exchanger includes: Based on the first temperature value and the second temperature value, determining the working state of the compressor in the outdoor unit; When the working state of the compressor in the outdoor unit is startup, determining a current startup cycle of the compressor; In the case where the startup cycle is the Nth time, a refrigerant heat exchange degree parameter of the heat exchanger is determined based on the first temperature value, and an air heat exchange efficiency parameter of the indoor unit is determined based on the second temperature value; wherein N is a positive integer greater than or equal to 2; wherein the refrigerant heat exchange degree parameter is a parameter indicating the heat exchange degree of the refrigerant in the heat exchanger, and the air heat exchange efficiency parameter is a parameter indicating the heat exchange efficiency of the air in the process of flowing through the indoor unit; Based on the refrigerant heat exchange degree parameter and the air heat exchange efficiency parameter, the opening of the expansion valve is controlled to adjust the flow rate of the refrigerant flowing into the heat exchanger.

6. The method according to claim 5, characterized in that The first type of temperature values ​​include the heat exchanger inlet pipe temperature and the heat exchanger outlet pipe temperature; the second type of temperature values ​​include the indoor return air temperature and the indoor outlet air temperature; the step of determining the heat exchange degree parameter of the heat exchanger based on the first type of temperature values, and determining the air heat exchange efficiency parameter of the indoor unit based on the second type of temperature values, comprises: Subtract the heat exchanger inlet temperature from the heat exchanger outlet temperature to obtain the refrigerant heat exchange degree parameter; The air heat exchange efficiency parameter is obtained by subtracting the indoor air outlet temperature from the indoor return air temperature.

7. The method according to claim 5, characterized in that The step of controlling the opening of the expansion valve based on the refrigerant heat exchange degree parameter and the air heat exchange efficiency parameter to adjust the flow rate of the refrigerant flowing into the heat exchanger comprises: Determine the numerical range to which the refrigerant heat exchange degree parameter belongs; When the refrigerant heat exchange degree parameter is less than a preset lower limit value, controlling the expansion valve to reduce the opening degree periodically and in a first preset step length; wherein the first preset step length is proportional to the absolute value of the refrigerant heat exchange degree parameter; When the refrigerant heat exchange degree parameter is greater than or equal to a first preset upper limit value, controlling the expansion valve to increase the opening degree periodically and in a first preset step size; When the refrigerant heat exchange degree parameter is greater than or equal to the preset lower limit value and less than the first preset upper limit value, the opening of the expansion valve is controlled according to the air heat exchange efficiency parameter to adjust the flow rate of the refrigerant flowing into the heat exchanger.

8. The method according to claim 7, characterized in that The step of controlling the opening of the expansion valve to adjust the flow rate of the refrigerant flowing into the heat exchanger according to the air heat exchange efficiency parameter when the refrigerant heat exchange degree parameter is greater than or equal to the preset lower limit value and less than the first preset upper limit value comprises: Determine the numerical range to which the air heat exchange efficiency parameter belongs; When the air heat exchange efficiency parameter is less than a preset lower limit value of the air heat exchange efficiency, the expansion valve is controlled to increase the opening periodically and in a second preset step; wherein the lower limit value of the air heat exchange efficiency is the air heat exchange efficiency target value minus the first deviation range; wherein the second preset step is proportional to the absolute value of the difference between the air heat exchange efficiency parameter and the air heat exchange efficiency target value; When the air heat exchange efficiency parameter is greater than or equal to a preset lower limit value of the air heat exchange efficiency and less than a preset upper limit value of the air heat exchange efficiency, the expansion valve is controlled to maintain the current opening; wherein the preset upper limit value of the air heat exchange efficiency is the air heat exchange efficiency target value plus a first deviation range; When the air heat exchange efficiency parameter is greater than or equal to a preset upper limit value of the air heat exchange efficiency, the expansion valve is controlled to reduce the opening degree periodically and in a second preset step size.

9. The method according to claim 8, characterized in that The method further comprises: After the Nth startup cycle ends, determining the duration of the Nth startup cycle; Determine the numerical interval of the duration of the Nth start cycle; When the numerical interval of the duration of the Nth startup cycle is less than the preset time lower limit, the air heat exchange efficiency target value is reduced by the first adjustment amount; wherein the preset time lower limit is the duration of the N-1th startup cycle minus the second deviation range; When the numerical interval of the duration of the Nth startup cycle is greater than a preset lower time limit and less than a preset upper time limit, the air heat exchange efficiency target value is reduced by a second adjustment amount; wherein the preset upper time limit is the duration of the N-1th startup cycle plus a second deviation range; wherein the second adjustment amount is lower than the first adjustment amount; When the numerical interval of the duration of the Nth startup cycle is greater than the preset time upper limit, the current air heat exchange efficiency target value is maintained unchanged.

10. The method according to claim 5, characterized in that The method further comprises: In the case where the startup cycle is the first time, determining a refrigerant heat exchange degree parameter of the heat exchanger based on the first type of temperature value; Based on the refrigerant heat exchange degree parameter, the opening of the expansion valve is controlled to adjust the flow rate of the refrigerant flowing into the heat exchanger.

11. The method according to claim 10, characterized in that The step of controlling the opening of the expansion valve based on the refrigerant heat exchange degree parameter to adjust the flow rate of the refrigerant flowing into the heat exchanger comprises: Determine the numerical range to which the refrigerant heat exchange degree parameter belongs; When the refrigerant heat exchange degree parameter is less than a preset lower limit value, controlling the expansion valve to reduce the opening degree periodically and in a first preset step length; wherein the first preset step length is proportional to the absolute value of the refrigerant heat exchange degree parameter; When the refrigerant heat exchange degree parameter is greater than or equal to a second preset upper limit value, controlling the expansion valve to increase the opening degree periodically and in a first preset step; wherein the second preset upper limit value is less than the first preset upper limit value; When the refrigerant heat exchange degree parameter is greater than or equal to the preset lower limit value and less than the second preset upper limit value, the expansion valve is controlled to maintain the current opening degree.

12. An air conditioner, characterized in that: The air conditioner is an air conditioner without communication between the indoor unit and the outdoor unit, and the indoor unit is the indoor unit described in any one of claims 1-3 or the indoor unit executing the method described in any one of claims 4-11.

Images