A heat pump system with a regenerator

Abstract

This invention relates to a heat pump system containing a regenerator. An electronic expansion valve is installed on the refrigerant pipeline between the water-side heat exchanger and the regenerator, and is connected in parallel with the regenerator. The system monitors the temperature and pressure of the liquid and gaseous refrigerants flowing into and out of the regenerator, and obtains a control method for the opening and closing, initial opening degree, and fine-tuning opening degree of the electronic expansion valve connected in parallel with the regenerator. This effectively controls the flow rate of the high-pressure, medium-temperature liquid refrigerant flowing into the regenerator. This setup and control method keep the compressor's suction superheat within a reasonable range, improving heat pump efficiency while preventing liquid slugging and ensuring reliable compressor operation.

Description

Technical Field

[0001] This invention relates to the field of heat pumps, and more particularly to a heat pump system containing a regenerator. Background Technology

[0002] A heat pump is a device that transfers heat energy from a lower heat source to a higher heat source. It typically consists of a compressor, condenser, expansion valve, and evaporator. When a heat pump needs to operate in a low-temperature environment, the refrigerant is difficult to evaporate in the evaporator at low temperatures. This can lead to unevaporated liquid refrigerant being drawn into the compressor and causing liquid slugging, potentially damaging the compressor, especially during startup or sudden changes in operating conditions.

[0003] Existing technology avoids the above problems by adding a regenerator at the compressor suction end. The refrigerant (lower temperature) exiting the evaporator is heated in the regenerator by the higher-temperature refrigerant from the water-side heat exchanger, causing the liquid portion of the refrigerant exiting the evaporator to absorb heat and evaporate, thus ensuring that the compressor suction is liquid-free. The conventional method of adding a regenerator involves installing a one-way valve at the refrigerant outlet of the water-side heat exchanger to control the refrigerant flow. This forces all higher-temperature refrigerant to pass through the regenerator, resulting in uncontrollable superheat of the return gas at the compressor suction end. This inability to control the return gas superheat leads to the following problems:

[0004] If the intake superheat is high, the heat pump's energy efficiency will be low.

[0005] If the intake superheat is low, it cannot be guaranteed that the compressor will not carry liquid into the intake. Summary of the Invention

[0006] Based on this, the purpose of the present invention is to provide a heat pump system containing a regenerator, wherein the system uses an electronic expansion valve to control the flow rate of the high-pressure medium-temperature refrigerant flowing through the regenerator, and is equipped with a corresponding electronic expansion valve control method.

[0007] A heat pump system with a regenerator includes a compressor, a four-way valve, a water-side heat exchanger, a regenerator, an air-side heat exchanger, an electronic expansion valve module, a temperature monitoring module, and a pressure monitoring module, all connected via refrigerant piping. A controller is electrically and / or communicatively connected to the compressor, the electronic expansion valve module, the temperature monitoring module, and the pressure monitoring module. The electronic expansion valve module includes a first electronic expansion valve and a second electronic expansion valve. The first electronic expansion valve is located on the refrigerant piping between the regenerator and the air-side heat exchanger and is used to control the refrigerant flow rate into the air-side heat exchanger. The second electronic expansion valve is located on the refrigerant piping between the water-side heat exchanger and the regenerator and is connected in parallel with the regenerator, used to control the refrigerant flow rate into the regenerator.

[0008] Furthermore, the controller controls the second electronic expansion valve using the following method:

[0009] S10 obtains the valve adjustment cycle information of the second electronic expansion valve and determines whether the second electronic expansion valve is in a large valve adjustment cycle:

[0010] If not, proceed to step S20;

[0011] If so, determine whether the second electronic expansion valve is in the first major valve adjustment cycle:

[0012] If so, control the second electronic expansion valve to close, and obtain the valve adjustment cycle information of the second electronic expansion valve in real time;

[0013] If not, obtain the valve adjustment monitoring information of the second electronic expansion valve, and determine whether the valve adjustment monitoring information of the second electronic expansion valve meets the preset valve adjustment conditions:

[0014] If the result is yes, then proceed to step S20;

[0015] If the result is negative, the second electronic expansion valve is closed, and the valve adjustment cycle information of the second electronic expansion valve is obtained in real time.

[0016] S20 acquires the inlet air temperature, outlet air temperature, inlet air pressure, outlet air pressure, inlet liquid pressure, and outlet liquid pressure of the regenerator, and calculates the initial opening degree of the second electronic expansion valve based on the above parameters and the preset target intake superheat.

[0017] S30 controls the second electronic expansion valve to adjust to the initial opening and runs for the first time period;

[0018] S40 acquires the current inlet and outlet temperatures of the regenerator and the preset target intake superheat, calculates the absolute value of the intake superheat difference, and, based on the relationship between the absolute value and the target intake superheat, controls the opening of the second electronic expansion valve to be finely adjusted based on the initial opening.

[0019] Furthermore, the initial opening of the second electronic expansion valve satisfies:

[0020]

[0021] In the formula: P g-in P represents the inlet pressure of the gaseous refrigerant at the inlet of the regenerator, in MPa. g-out This indicates the outlet pressure of the gaseous refrigerant at the outlet of the regenerator, expressed in MPa; P l-in P represents the inlet pressure of the liquid refrigerant at the inlet of the regenerator, in MPa. l-out This indicates the outlet pressure of the liquid refrigerant at the outlet end of the regenerator, in MPa. This represents the target enthalpy of return gas, expressed in kJ / (kg·K); H g-in The inlet enthalpy of the gaseous refrigerant is expressed in kJ / (kg·K); H g-outThe output enthalpy of the gaseous refrigerant is expressed in kJ / (kg·K); C0 represents the correction value for the opening degree, which is a preset dimensionless constant.

[0022] Further, step S40 includes the following sub-steps:

[0023] S41 obtains the current inlet temperature of the regenerator. With exhaust temperature The current intake superheat is calculated. The current inhalation superheat satisfy:

[0024]

[0025] S42 determines the current inhalation superheat. With the preset target intake superheat The difference in intake superheat ΔT at the current moment is calculated. t absolute value |ΔT t |;The current inhalation superheat difference ΔT t absolute value |ΔT t | Satisfies:

[0026]

[0027] S43 calculates the current intake superheat difference ΔT t absolute value |ΔT t |Target Inhalation Superheat The relationship between the control and the control of the opening degree of the second electronic expansion valve is used to finely adjust the opening degree based on the initial opening degree.

[0028] Furthermore, in step S43, the opening degree of the second electronic expansion valve is finely adjusted based on the initial opening degree in the following manner:

[0029] when At the same time, the opening degree of the second electronic expansion valve is controlled to make the first fine adjustment ΔP1 adjustment;

[0030] when At the same time, the opening degree of the second electronic expansion valve is controlled to adjust the second fine-tuning opening degree ΔP2;

[0031] when At the same time, the opening degree of the second electronic expansion valve is controlled to adjust the third fine-tuning opening degree ΔP3;

[0032] when At that time, the valve is not adjusted.

[0033] Furthermore, the valve monitoring information in step S10 includes compressor frequency change ΔF and / or ambient temperature change ΔT. EAnd / or the current water-side heat exchanger inlet water temperature And the preset valve control conditions that correspond one-to-one with the above valve control monitoring information:

[0034] —The compressor frequency change ΔF is greater than or equal to the compressor frequency change threshold ΔF DV ;

[0035] —Ambient temperature change ΔT E Greater than or equal to the ambient temperature change threshold

[0036] —Water inlet water temperature T of the water-side heat exchanger w-in The threshold for judging water-side heat exchanger inlet water temperature is greater than or equal to the threshold value.

[0037] The above is achieved by varying the compressor frequency ΔF and the ambient temperature ΔT. E and the current inlet water temperature of the water-side heat exchanger The method for judging valve monitoring information can be simplified to selecting any one of the valve monitoring information for control judgment; or selecting two or three valve monitoring information to satisfy one of them for control judgment.

[0038] Compared with existing technologies, this invention, by installing an electronic expansion valve in parallel with the refrigerant pipeline between the water-side heat exchanger and the regenerator, and monitoring the temperature and pressure of the liquid and gaseous refrigerants flowing into and out of the regenerator, obtains a control method for the opening and closing, initial opening, and fine-tuning opening of the electronic expansion valve connected in parallel with the regenerator. This effectively controls the flow rate of the high-pressure, medium-temperature liquid refrigerant flowing into the regenerator. This setup and control method keep the compressor's suction superheat within a reasonable range, improving heat pump efficiency while preventing liquid slugging and ensuring reliable compressor operation.

[0039] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the structure of the present invention;

[0041] Figure 2 This is a schematic diagram of the controller control process of the present invention. Detailed Implementation

[0042] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings of the embodiments of the present invention.

[0043] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that, unless otherwise stated, “a plurality” means two or more; “and / or” means and includes any or all possible combinations of one or more associated listed items; “first,” “second,” “third,” etc., are used only to distinguish and are not used to describe a particular order or sequence, nor should they be construed as indicating or implying relative importance.

[0044] To address the problem of uncontrollable superheat of compressor suction return gas in heat pump systems with regenerators operating in low-temperature environments, this application provides a heat pump system with a regenerator. This system uses an electronic expansion valve to control the flow rate of high-pressure medium-temperature refrigerant flowing through the regenerator, and, in conjunction with a designed electronic expansion valve control method, can control the compressor suction superheat to remain within a reasonable range.

[0045] For specific implementation details, please refer to [link / reference]. Figure 1 The heat pump system with a regenerator proposed in this invention includes a compressor 10, a four-way valve 20, a water-side heat exchanger 30, a regenerator 40, an air-side heat exchanger 50, an electronic expansion valve module 60, a temperature monitoring module 70, a pressure monitoring module 80, a fan (not shown), a controller (not shown), and other auxiliary pipes. The compressor 10, four-way valve 20, water-side heat exchanger 30, regenerator 40, and air-side heat exchanger 50 are connected via refrigerant circulation piping. The controller is electrically and / or communicatively connected to the compressor 10, electronic expansion valve module 60, temperature monitoring module 70, and pressure monitoring module 80.

[0046] The electronic expansion valve module 60 includes a first electronic expansion valve 61 and a second electronic expansion valve 62. The first electronic expansion valve 61 is installed on the refrigerant pipeline between the regenerator 40 and the air-side heat exchanger 50, and is used to control the refrigerant flow rate into the air-side heat exchanger 50. The second electronic expansion valve 62 is installed on the refrigerant pipeline between the water-side heat exchanger 30 and the regenerator 40 and is connected in parallel with the regenerator 40, and is used to control the refrigerant flow rate into the regenerator. The medium-temperature, high-pressure refrigerant flowing out of the water-side heat exchanger 30, after being regulated by the second electronic expansion valve 62, enters the regenerator 40 to exchange heat with the low-temperature, low-pressure refrigerant flowing out of the air-side heat exchanger 50, and then flows out. After being regulated by the first electronic expansion valve 61, it enters the air-side heat exchanger 50 to exchange heat with the air. The low-temperature, low-pressure refrigerant flowing out of the air-side heat exchanger 50 enters the regenerator 40 to exchange heat with the medium-temperature, high-pressure refrigerant flowing out of the water-side heat exchanger 30, and then enters the suction end of the compressor 10.

[0047] The temperature monitoring module 70 includes a first temperature sensor 71, a second temperature sensor 72, a third temperature sensor 73, a fourth temperature sensor 74, a fifth temperature sensor 75, and a sixth temperature sensor 76. The first temperature sensor 71 is located near the liquid inlet of the regenerator 40 and is used to collect the temperature signal of the medium-temperature liquid refrigerant flowing into the regenerator 40, and to display the refrigerant's inlet temperature T. l-in The data is transmitted to the controller. The second temperature sensor 72 is located near the liquid outlet of the regenerator 40 to collect the temperature signal of the medium-temperature liquid refrigerant flowing out of the regenerator 40, and to transmit the outlet temperature T. l-out The data is transmitted to the controller. The third temperature sensor 73 is located near the inlet of the regenerator 40 to collect the temperature signal of the low-temperature gaseous refrigerant flowing into the liquid return unit 40, and to transmit the inlet temperature T. g-in The data is transmitted to the controller. The fourth temperature sensor 74 is located near the outlet of the regenerator 40 to collect the temperature signal of the low-temperature gaseous refrigerant flowing out of the liquid return unit 40, and to transmit the outlet temperature T. g-out The data is transmitted to the controller. The fifth temperature sensor 75 is used to collect the ambient temperature signal and transmit the ambient temperature T. E The fifth temperature sensor 75 can be located on the outside of the air-side heat exchanger 50 or on the heat pump system casing; this application makes no limitation on this. The sixth temperature sensor 76 is located at the inlet of the water-side heat exchanger and is used to collect the temperature signal of the water flowing into the water-side heat exchanger and transmit the inlet water temperature T... w-in Transmitted to the controller.

[0048] The pressure monitoring module 80 includes a first pressure sensor 81, a second pressure sensor 82, a third pressure sensor 83, and a fourth pressure sensor 84. The first pressure sensor 81 is located near the liquid inlet of the regenerator 40 and is used to collect the pressure signal of the medium-temperature liquid refrigerant flowing into the regenerator 40, and to transmit the refrigerant inlet pressure P. l-in The pressure is transmitted to the controller. The second pressure sensor 82 is located near the liquid outlet of the regenerator 40 to collect the pressure signal of the medium-temperature liquid refrigerant flowing out of the regenerator 40 and to transmit the outlet pressure P. l-out The pressure is transmitted to the controller. The third pressure sensor 83 is located near the inlet of the regenerator 40 to collect the pressure signal of the low-temperature gaseous refrigerant flowing into the liquid return unit 40, and to transmit the inlet pressure P. g-in The pressure is transmitted to the controller. The fourth pressure sensor 84 is located near the outlet of the regenerator 40 to collect the pressure signal of the low-temperature gaseous refrigerant flowing out of the liquid return unit 40, and to transmit the outlet pressure P. g-out Transmitted to the controller.

[0049] The controller includes a storage unit and a processing unit.

[0050] The storage unit is used to store various preset values ​​of the heat pump system, including the target return gas superheat. compressor frequency change threshold ΔF DV , threshold of ambient temperature change Threshold for judging the inlet water temperature of water-side heat exchanger Fan speed change threshold ΔV DV ; and at each time point, the temperature monitoring module 70 collected the inlet liquid temperature T. l-in , liquid outlet temperature T l-out Intake air temperature T g-in Outlet temperature T g-out and ambient temperature T E The pressure monitoring module 80 collects the inlet pressure P. l-in Discharge pressure P l-out Intake pressure P g-in and exhaust pressure P g-out .

[0051] The processing unit is used for calculations, including based on the intake air temperature T. g-in and outlet air temperature T g-out Calculate the intake superheat ΔT g According to the intake air temperature T g-in and target intake superheat Calculate the target return gas temperature Based on intake pressure P g-in and exhaust pressure P g-out Calculate the target intake pressure And based on the target return gas temperature and target intake pressure Calculate the target return gas enthalpy. And according to the inlet pressure P l-in Discharge pressure P l-out Intake pressure P g-in and exhaust pressure P g-out and intake enthalpy H g-in Enthalpy of exhaust gas H g-out Target return enthalpy The functions are: 1) to calculate the initial opening P0 of the second electronic expansion valve 62; 2) to make a comparison and judgment; and 3) to output an opening adjustment signal to the second electronic expansion valve 62 based on the judgment result, thereby controlling the flow rate of the medium-temperature and high-pressure refrigerant entering the regenerator.

[0052] Please see Figure 2 The controller adjusts the opening of the second electronic expansion valve 62 of the heat pump system containing the regenerator through the following steps.

[0053] S10 obtains the valve adjustment cycle information of the second electronic expansion valve and determines whether the second electronic expansion valve is in a large valve adjustment cycle:

[0054] If so, determine whether the second electronic expansion valve is in the first major valve adjustment cycle:

[0055] If so, the second electronic expansion valve is closed, and the system's operating status is acquired in real time;

[0056] If not, then obtain the valve adjustment monitoring information of the second electronic expansion valve, and determine whether the valve adjustment monitoring information of the second electronic expansion valve meets the preset valve adjustment conditions:

[0057] If the result is yes, then proceed to step S20;

[0058] If the result is negative, the second electronic expansion valve will be closed, and the system's operating status will be acquired in real time.

[0059] If not, proceed to step S20.

[0060] In practice, the cycle of the large regulating valve is set to 1 minute to 5 minutes.

[0061] Valve monitoring information includes compressor frequency change ΔF and / or ambient temperature change ΔT. E and / or the fan speed change ΔV and / or the current water-side heat exchanger inlet water temperature The compressor frequency change ΔF is the compressor frequency F at the current moment. t Compressor frequency F at the previous moment t-1 The absolute value of the difference; the change in ambient temperature ΔT E The ambient temperature at the current moment Compared to the ambient temperature at the previous moment The absolute value of the difference; the change in fan speed ΔV is the fan speed V at the current moment. t Compared with the fan speed V at the previous moment t-1 The absolute value of the difference.

[0062] The preset valve control conditions are to satisfy any of the following valve control conditions:

[0063] 1) The compressor frequency change ΔF is greater than or equal to the compressor frequency change threshold ΔF DV ;

[0064] 2) Ambient temperature change ΔT E Greater than or equal to the ambient temperature change threshold

[0065] 3) The fan speed change ΔV is greater than the fan speed change threshold ΔV DV ;

[0066] 4) Water inlet temperature T of the water-side heat exchanger w-in The threshold for judging water-side heat exchanger inlet water temperature is greater than or equal to the threshold value.

[0067] Preset compressor frequency change threshold ΔF DV The value range is 3Hz-5Hz; threshold for ambient temperature change. The value range is 7℃-9℃; threshold for judging the inlet water temperature of the water-side heat exchanger. The value range is 2℃-4℃; the threshold value for fan speed variation ΔV DV The value range is 90rpm-110rpm.

[0068] The above is achieved by varying the compressor frequency ΔF and the ambient temperature ΔT. E The fan speed change ΔV and the current water inlet temperature of the water-side heat exchanger. The method for judging valve monitoring information can be simplified to selecting any one of the valve monitoring information for control judgment; or selecting two, three or four valve monitoring information to satisfy one of them for control judgment. This application does not impose any restrictions.

[0069] S20 obtains the inlet air temperature T of the regenerator 40. g-in Outlet temperature T g-out Intake pressure P g-in , exhaust pressure P g-out Inlet pressure P l-in and liquid outlet pressure P l-out Based on the above parameters, the initial opening degree P0 of the second electronic expansion valve 62 is calculated.

[0070] Specifically, the initial opening degree P0 of the second electronic expansion valve 62 is calculated in the following manner.

[0071] 1) Based on the intake air temperature T g-in and intake pressure P g-in Calculated Intake enthalpy H g-in .

[0072] Intake enthalpy H g-in satisfy:

[0073] H g-in =αP g-in 2 +βP g-in +γT g-out 2 +δT g-out +C1 (1)

[0074] In the formula: α, β, γ, and η are the weighting coefficients of each item, and C1 is a constant, which is an empirical value.

[0075] 2) Based on the outlet air temperature T g-out and exhaust pressure P g-out Calculated Exhaust enthalpy H g-out .

[0076] Exhaust enthalpy H g-out satisfy:

[0077] H g-out =εP g-out 2 +ξP g-out +ηT g-in 2 +θT g-in +C2 (2)

[0078] In the formula: ε, ξ, η, θ are the weighting coefficients of each item, and C2 is a constant, which is an empirical value.

[0079] 3) Based on the intake air temperature T g-in and the preset target intake superheat The target return gas temperature was calculated.

[0080] Target return gas temperature satisfy:

[0081]

[0082] In the formula: T g-in Indicates intake air temperature, in °C. This indicates the preset target intake superheat, in °C.

[0083] Among them, the preset target intake superheat The value range is 1℃~8℃.

[0084] 4) Based on the intake pressure P g-in and exhaust pressure P g-out The target return pressure was calculated.

[0085] Target return pressure satisfy:

[0086]

[0087] In the formula: P g-in This indicates the intake pressure, expressed in MPa (P). g-out This indicates the outlet pressure, expressed in MPa.

[0088] 5) Based on the target return gas temperature and target return pressure Calculated Target enthalpy of return

[0089] Target enthalpy of return satisfy:

[0090]

[0091] In the formula: F represents the current frequency of the compressor, F MAX The maximum frequency of the compressor is indicated, generally not exceeding 120, and is determined by the compressor specifications. κ is an influencing factor, with a value range of (50-200).

[0092] 6) Based on the intake pressure P g-in , exhaust pressure P g-out Inlet pressure P l-in Discharge pressure P l-out Intake enthalpy H g-in Enthalpy of exhaust gas H g-out Target return enthalpy The initial opening degree P0 of the second electronic expansion valve 62 was calculated.

[0093] The initial aperture P0 satisfies:

[0094]

[0095] In the formula: P g-in P represents the inlet pressure of the gaseous refrigerant at the inlet of the regenerator, in MPa. g-out This indicates the outlet pressure of the gaseous refrigerant at the outlet of the regenerator, expressed in MPa; P l-in P represents the inlet pressure of the liquid refrigerant at the inlet of the regenerator, in MPa. l-out This indicates the outlet pressure of the liquid refrigerant at the outlet end of the regenerator, in MPa. This represents the target enthalpy of return gas, expressed in kJ / (kg·K); H g-in The inlet enthalpy of the gaseous refrigerant is expressed in kJ / (kg·K); H g-out The output enthalpy of the gaseous refrigerant is expressed in kJ / (kg·K); C0 represents the correction value for the opening degree, which is a preset dimensionless constant.

[0096] The value of the correction value C0 for the opening ranges from -100 to 100.

[0097] S30 controls the second electronic expansion valve 62 to adjust to the initial opening P0 and runs for the first time period t1.

[0098] S40 obtains the current inlet air temperature of the regenerator. outlet air temperature With the preset target intake superheat The difference in intake superheat ΔT was calculated. t absolute value |ΔT t | and according to the absolute value |ΔT t |Target Inhalation Superheat The relationship is such that the opening degree of the second electronic expansion valve 62 is finely adjusted based on the initial opening degree P0.

[0099] This step includes the following sub-steps.

[0100] S41 obtains the current inlet temperature of the regenerator. With exhaust temperature The current intake superheat is calculated.

[0101] Current moment of inhalation superheat satisfy:

[0102]

[0103] S42 determines the current inhalation superheat. With the preset target intake superheat The difference in intake superheat ΔT at the current moment is calculated. t absolute value |ΔT t |

[0104] Current intake superheat difference ΔT t absolute value |ΔT t | Satisfies:

[0105]

[0106] S43 calculates the current intake superheat difference ΔT t absolute value |ΔT t |Target Inhalation Superheat The relationship is such that the opening degree of the second electronic expansion valve 62 is finely adjusted based on the initial opening degree P0.

[0107] In practice, the difference in intake superheat ΔT at the current moment is used as the basis for implementation. t absolute value |ΔT t |Target Inhalation Superheat In accordance with the relationship, the opening degree of the second electronic expansion valve 62 is finely adjusted based on the initial opening degree P0 in the following manner:

[0108] when The opening degree of the second electronic expansion valve 62 is controlled to perform the first fine-tuning adjustment ΔP1;

[0109] when The opening degree of the second electronic expansion valve 62 is controlled to adjust the second fine-tuning opening degree ΔP2;

[0110] when The opening degree of the second electronic expansion valve 62 is controlled to adjust the third fine-tuning opening degree ΔP3;

[0111] when No valve adjustment.

[0112] Set the first fine-tuning opening ΔP1 to 10 to 20 steps; the second fine-tuning opening ΔP2 to 7 to 9 steps; and the third fine-tuning opening ΔP3 to 1 to 6 steps.

[0113] The heat pump system of this application, by installing an electronic expansion valve in parallel with the refrigerant pipeline between the water-side heat exchanger and the regenerator, and monitoring the temperature and pressure of the liquid and gaseous refrigerants flowing into and out of the regenerator, obtains a control method for the opening and closing, initial opening, and fine-tuning opening of the electronic expansion valve connected in parallel with the regenerator. This effectively controls the flow rate of the high-pressure, medium-temperature liquid refrigerant flowing into the regenerator. This setup and control method can keep the compressor's suction superheat within a reasonable range, improving the heat pump's energy efficiency while avoiding liquid slugging in the compressor and ensuring reliable compressor operation.

[0114] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and the present invention also intends to include these modifications and variations.

Claims

1. A heat pump system with a regenerator, comprising a compressor, a four-way valve, a water-side heat exchanger, a regenerator, an air-side heat exchanger, an electronic expansion valve module, a temperature monitoring module, and a pressure monitoring module, all connected via refrigerant piping, and a controller electrically and / or communicatively connected to the compressor, the electronic expansion valve module, the temperature monitoring module, and the pressure monitoring module. The electronic expansion valve module includes a first electronic expansion valve and a second electronic expansion valve. The first electronic expansion valve is disposed on the refrigerant piping between the regenerator and the air-side heat exchanger and is used to control the refrigerant flow rate into the air-side heat exchanger. The second electronic expansion valve is disposed on the refrigerant piping between the water-side heat exchanger and the regenerator and is connected in parallel with the regenerator, and is used to control the refrigerant flow rate into the regenerator. The system is characterized in that... The controller controls the second electronic expansion valve using the following method: S10 Obtain the valve adjustment cycle information of the second electronic expansion valve and determine whether the second electronic expansion valve is in a large valve adjustment cycle: If not, proceed to step S20; If so, determine whether the second electronic expansion valve is in the first major valve adjustment cycle: If so, control the second electronic expansion valve to close, and obtain the valve adjustment cycle information of the second electronic expansion valve in real time; If not, obtain the valve adjustment monitoring information of the second electronic expansion valve, and determine whether the valve adjustment monitoring information of the second electronic expansion valve meets the preset valve adjustment conditions: If the result is yes, then proceed to step S20; If the result is negative, the second electronic expansion valve is closed, and the valve adjustment cycle information of the second electronic expansion valve is obtained in real time. S20 acquires the inlet air temperature, outlet air temperature, inlet air pressure, outlet air pressure, inlet liquid pressure, and outlet liquid pressure of the regenerator, and calculates the initial opening degree of the second electronic expansion valve based on the above parameters and the preset target intake superheat; wherein, the initial opening degree of the second electronic expansion valve satisfies: In the formula: This indicates the inlet pressure of the gaseous refrigerant at the inlet end of the regenerator, in MPa. This indicates the outlet pressure of the gaseous refrigerant at the outlet end of the regenerator, in MPa. This indicates the inlet pressure of the liquid refrigerant at the inlet end of the regenerator, in MPa. This indicates the outlet pressure of the liquid refrigerant at the outlet end of the regenerator, in MPa. This represents the target enthalpy of return gas, expressed in kJ / (kg·K). This indicates the intake enthalpy of the gaseous refrigerant, expressed in kJ / (kg·K). This represents the enthalpy of the gaseous refrigerant, expressed in kJ / (kg·K). The correction value for the opening is a preset dimensionless constant. S30 controls the second electronic expansion valve to adjust to the initial opening and runs for the first time period; S40 obtains the current inlet and outlet temperatures of the regenerator and the preset target intake superheat, calculates the absolute value of the intake superheat difference, and, based on the relationship between the absolute value and the target intake superheat, controls the opening of the second electronic expansion valve to be finely adjusted based on the initial opening.

2. The heat pump system according to claim 1, characterized in that, Correction value for opening The value range is -100 to 100.

3. The heat pump system according to claim 1 or 2, characterized in that, Step S40 includes the following sub-steps: S41 Get the current inlet air temperature of the regenerator With exhaust temperature The current intake superheat is calculated. The current intake superheat satisfy: ； S42 Based on the current inhalation superheat With the preset target intake superheat The difference in intake superheat at the current moment is calculated. absolute value The difference in intake superheat at the current moment; absolute value satisfy: ； S43 Based on the current inhalation superheat difference absolute value With target intake superheat The relationship between the control and the control of the opening degree of the second electronic expansion valve is used to finely adjust the opening degree based on the initial opening degree.

4. The heat pump system according to claim 3, characterized in that, Step S43 fine-tunes the opening of the second electronic expansion valve based on the initial opening as follows: when At that time, the opening degree of the second electronic expansion valve is controlled to perform the first fine adjustment. adjust; when At the same time, the opening degree of the second electronic expansion valve is controlled for a second fine-tuning adjustment. adjust; when At the same time, the opening degree of the second electronic expansion valve is controlled to perform a third fine-tuning adjustment. adjust; when At that time, the valve is not adjusted.

5. The heat pump system according to claim 4, characterized in that, First fine-tuning of opening The steps are 10 to 20; the second fine-tuning is to adjust the opening. The process consists of 7 to 9 steps; the third step involves fine-tuning the opening. It consists of 1 to 6 steps.

6. The heat pump system according to any one of claims 1, 2, 4, and 5, characterized in that, The valve monitoring information in step S10 includes compressor frequency changes. and / or changes in ambient temperature And / or the current water-side heat exchanger inlet water temperature And the preset valve control conditions that correspond one-to-one with the above valve control monitoring information: —Compressor frequency variation Greater than or equal to the compressor frequency change threshold ; —Changes in ambient temperature Greater than or equal to the ambient temperature change threshold ; —Inlet water temperature of water-side heat exchanger The threshold for judging water-side heat exchanger inlet water temperature is greater than or equal to the threshold value. ; The above is achieved through changes in compressor frequency. Changes in ambient temperature and the current inlet water temperature of the water-side heat exchanger The method for judging valve monitoring information can be simplified to selecting any one of the valve monitoring information for control judgment; or selecting two or three valve monitoring information to satisfy one of them for control judgment.

7. The heat pump system according to claim 6, characterized in that, Preset compressor frequency change threshold The value range is 3Hz-5Hz; threshold for ambient temperature change. The value range is 7℃-9℃; threshold for judging the inlet water temperature of the water-side heat exchanger. The value range is 2℃-4℃.

8. The heat pump system according to any one of claims 1, 2, 4, 5, and 7, characterized in that, The heat pump system also includes a fan, and the valve monitoring information in step S10 also includes changes in fan speed. and changes in fan speed Corresponding preset valve control conditions: —Fan speed variation Greater than the fan speed change threshold ; And the threshold for fan speed change The value range is 90rpm-110rpm.

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