Heat pump system, control method of heat pump system, and control device thereof

Abstract

The application provides a heat pump system, a control method of the heat pump system and a control device thereof. The heat pump unit comprises an indoor heat exchanger, an electronic expansion valve, an outdoor heat exchanger, a four-way valve and a compressor, the four-way valve is provided with a suction branch between the suction port of the compressor; the indoor heat exchanger and the outdoor heat exchanger are provided with a first heating branch, a second heating branch and a third heating branch in parallel, and are all provided with a first check valve; the first heating branch is provided with a first control valve and a heat storage device which is coupled with the suction branch in sequence; the second heating branch is provided with a heat-coupled enthalpy-increasing heat exchanger and an enthalpy-increasing auxiliary path, the enthalpy-increasing auxiliary path is connected to an enthalpy-increasing port of the compressor and is provided with an enthalpy-increasing control valve; the third heating branch is provided with a second control valve, a heat-coupled backflow auxiliary path and a backflow heat exchanger, the backflow auxiliary path is connected to the suction branch and is provided with a backflow control valve. The heat pump unit can produce high heat in a low-temperature environment when the user demand outlet water temperature is high.

Description

Technical Field

[0001] This invention relates to the field of electrical technology, and in particular to heat pump systems, control methods for heat pump systems, and control devices thereof. Background Technology

[0002] In related technologies, based on the temperature-limited operating conditions of compressors on the market, when the refrigerant return gas temperature is below -40℃, the viscosity coefficient of the compressor oil increases after mixing with the low-temperature refrigerant. This requires the compressor heating belt to heat the oil for more than 120 minutes before the oil temperature can rise for startup, resulting in excessively long startup times and increased user costs. Furthermore, when existing heat pump units operate in heating mode in ultra-low temperature environments (e.g., outdoor ambient temperatures below -30℃), the evaporator-side return gas temperature reaches a maximum of -30℃, making it impossible to guarantee the dryness of the refrigerant in the return gas. Additionally, excessively low return gas refrigerant temperatures can easily increase compressor power and cause excessively low exhaust temperatures.

[0003] Therefore, in the harsh climate of frigid regions, the existing heat pump units have limited heat production capacity and low energy efficiency. The units can only rely on the energy storage electric heating water tank to maintain heating, and the heat production capacity and energy efficiency of the units themselves cannot meet the actual needs. Summary of the Invention

[0004] This invention provides a heat pump system, a control method for the heat pump system, and a control device thereof, to overcome the deficiencies in the prior art and achieve the following technical effects: when the outdoor ambient temperature is low and the user requires a high outlet water temperature, at least one of the first heating branch, the second heating branch, and the third heating branch can be turned on and operated to achieve the purpose of generating high heat in a low-temperature environment.

[0005] A heat pump unit according to a first aspect of the present invention includes:

[0006] The indoor heat exchanger, electronic expansion valve, outdoor heat exchanger, four-way valve and compressor are connected by refrigerant pipes, wherein the four-way valve and the suction port of the compressor are connected by a suction branch.

[0007] The indoor heat exchanger and the outdoor heat exchanger are provided with three parallel heating branches, including a first heating branch, a second heating branch and a third heating branch, and each branch is provided with a first one-way valve that flows toward the outdoor heat exchanger. The electronic expansion valve is connected in series with the second heating branch and the third heating branch and in parallel with the first heating branch.

[0008] The first heating branch is provided with a first control valve and a heat storage device in sequence, and the heat storage device is thermally coupled to the intake branch.

[0009] The second heating branch is equipped with a thermally coupled enthalpy-increasing heat exchanger and an enthalpy-increasing auxiliary circuit. The two ends of the enthalpy-increasing auxiliary circuit are respectively connected to the second heating branch and the enthalpy-increasing port of the compressor. An enthalpy-increasing control valve is provided on the enthalpy-increasing auxiliary circuit.

[0010] The third heating branch is equipped with a thermally coupled reflux auxiliary path and a reflux heat exchanger. The two ends of the reflux auxiliary path are respectively connected to the third heating branch and the suction branch. The third heating branch is also equipped with a second control valve, and the reflux auxiliary path is equipped with a reflux control valve.

[0011] According to one embodiment of the present invention, the inlet and outlet of the heat storage device are respectively provided with a first temperature sensor and a second temperature sensor, and the first control valve is a temperature-sensing control valve and is connected to the first temperature sensor and the second temperature sensor respectively.

[0012] According to one embodiment of the present invention, a flash evaporation device is further provided on the intake heating branch, and the flash evaporation device is located downstream of the third heating branch.

[0013] According to one embodiment of the present invention, a refrigeration branch is further provided between the indoor heat exchanger and the electronic expansion valve, and a second one-way valve is provided on the refrigeration branch to flow toward the side of the indoor heat exchanger.

[0014] A control method for a heat pump unit based on the first aspect of the present invention, according to a second aspect embodiment of the present invention, includes:

[0015] When the heat pump unit is in heating mode, the outdoor ambient temperature and the target outlet water temperature of the heat pump unit are obtained.

[0016] Control logic is generated based on the outdoor ambient temperature and / or the target outlet water temperature, and the operating status and operating parameters of the heat storage device, the enthalpy-increasing heat exchanger and the reflux heat exchanger are controlled according to the control logic.

[0017] According to an embodiment of the present invention, the step of generating control logic based on the outdoor ambient temperature and / or the target outlet water temperature, and controlling the operating state and operating parameters of the heat storage device, the enthalpy-increasing heat exchanger, and the reflux heat exchanger according to the control logic specifically includes:

[0018] When the outdoor ambient temperature is within the first outdoor temperature zone, the first control valve, the enthalpy increase control valve, the second control valve, and the reflux control valve are all closed so that the heat storage device, the enthalpy increase heat exchanger, and the reflux heat exchanger are all kept in the closed state.

[0019] Alternatively, if the outdoor ambient temperature is in the second outdoor temperature zone, the enthalpy increase control valve is opened to make the enthalpy increase heat exchanger work, and the working status and working parameters of the heat storage device and the reflux heat exchanger are controlled according to the range of the target outlet water temperature.

[0020] Wherein, the first outdoor temperature zone is greater than zero, and the second outdoor temperature zone is less than zero.

[0021] According to an embodiment of the present invention, the step of controlling the operating state and operating parameters of the heat storage device and the reflux heat exchanger according to the range of the target outlet water temperature specifically includes:

[0022] When the target outlet water temperature is in the first outlet water temperature zone, the first control valve, the second control valve, and the reflux control valve are all closed so that the heat storage device and the reflux heat exchanger remain in the closed state.

[0023] Alternatively, if the target outlet water temperature is in the second outlet water temperature zone, the first control valve is opened to put the heat storage device into operation, and the second control valve and the return control valve are both closed to keep the return heat exchanger in a closed state.

[0024] The first outlet water temperature zone is smaller than the second outlet water temperature zone.

[0025] According to an embodiment of the present invention, the step of generating control logic based on the outdoor ambient temperature and / or the target outlet water temperature, and controlling the operating state and operating parameters of the heat storage device, the enthalpy-increasing heat exchanger, and the reflux heat exchanger according to the control logic, further includes:

[0026] Based on the outdoor ambient temperature being in the third outdoor temperature zone, the first control valve, the enthalpy-increasing control valve, the second control valve, and the reflux control valve are all opened so that the heat storage device, the enthalpy-increasing heat exchanger, and the reflux heat exchanger are all in working condition, wherein the third outdoor temperature zone is smaller than the second outdoor temperature zone.

[0027] After confirming that the first control valve, the enthalpy increase control valve, the second control valve, and the reflux control valve are all open, the suction temperature of the compressor is obtained.

[0028] Based on the intake temperature and the outdoor ambient temperature, the opening degree of at least one of the first control valve, the enthalpy increase control valve, the reflux control valve, and the electronic expansion valve is controlled and adjusted.

[0029] According to an embodiment of the present invention, the step of controlling and adjusting the opening degree of at least one of the first control valve, the enthalpy increase control valve, the reflux control valve, and the electronic expansion valve based on the intake temperature and the outdoor ambient temperature specifically includes:

[0030] When the difference between the intake temperature and the outdoor ambient temperature is less than or equal to a first set temperature difference, the opening degree of the first control valve is increased to the first heat storage opening degree, the opening degree of the return control valve is increased to the first return opening degree, and the opening degree of the electronic expansion valve is decreased to the first expansion opening degree.

[0031] Alternatively, if the difference between the intake temperature and the outdoor ambient temperature is greater than or equal to the second set temperature difference, the opening degree of the first control valve is controlled to decrease to the second heat storage opening degree, the opening degree of the return control valve is controlled to decrease to the second return opening degree, and the opening degree of the electronic expansion valve is controlled to increase to the second expansion opening degree.

[0032] According to one embodiment of the present invention, after the step of controlling and adjusting the opening degree of at least one of the first control valve, the enthalpy increase control valve, the reflux control valve, and the electronic expansion valve based on the intake temperature and the outdoor ambient temperature, the method further includes:

[0033] After the heat pump unit has been running for at least a preset time, the adjusted difference between the current suction temperature and the outdoor ambient temperature is obtained;

[0034] If the adjusted temperature difference is less than or equal to the first set temperature difference or greater than or equal to the second set temperature difference, the reflux control valve and the electronic expansion valve are controlled to return to their initial reflux valve opening and initial expansion valve opening, respectively.

[0035] The actual exhaust superheat and target exhaust superheat of the compressor are obtained, and the opening degree of the electronic expansion valve is controlled and adjusted according to the actual exhaust superheat and the target exhaust superheat.

[0036] According to an embodiment of the present invention, the step of controlling and adjusting the opening of the electronic expansion valve based on the actual exhaust superheat and the target exhaust superheat specifically includes:

[0037] When the actual exhaust superheat is greater than the target exhaust superheat, the opening of the electronic expansion valve is controlled to increase the first variable opening.

[0038] When the actual exhaust superheat is less than the target exhaust superheat, the opening of the electronic expansion valve is controlled to decrease to a second variable opening.

[0039] According to one embodiment of the present invention, the initial reflux valve opening, the initial expansion valve opening, and the target exhaust superheat are all obtained at least based on the outdoor ambient temperature.

[0040] A control device for a heat pump unit based on the first aspect embodiment of the present invention, according to a third aspect embodiment of the present invention, includes:

[0041] The acquisition module is used to acquire the outdoor ambient temperature and the target outlet water temperature of the heat pump unit when the heat pump unit is in heating mode.

[0042] The control module is used to generate control logic based on the outdoor ambient temperature and / or the target outlet water temperature, and to control the operating status and operating parameters of the heat storage device, the enthalpy-increasing heat exchanger and the reflux heat exchanger according to the control logic.

[0043] This invention provides a heat pump unit with three heating branches, each consisting of a heat storage device, a gas injection enthalpy enhancement device, and a reflux device (reflux auxiliary path, reflux heat exchanger, and reflux control valve). The heat storage device utilizes waste heat to increase the compressor's suction superheat, ensuring the refrigerant dryness and temperature on the suction side. The gas injection enthalpy enhancement device subcools the high-temperature refrigerant exiting the indoor heat exchanger and increases the compressor's discharge volume, reducing the discharge temperature and enhancing heating capacity. The reflux device returns a portion of the high-temperature refrigerant exiting the indoor heat exchanger to the compressor's suction side, ensuring the refrigerant dryness and sensible heat on the compressor's suction side.

[0044] As shown above, all three heating branches can assist the heat pump unit in generating high heat in low-temperature environments. Thus, when the outdoor ambient temperature is low and the user requires a high outlet water temperature, at least one of the first, second, and third heating branches can be turned on and put into operation to achieve the purpose of generating high heat in low-temperature environments. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0046] Figure 1 This is a schematic diagram of the structure of the heat pump unit provided by the present invention;

[0047] Figure 2 This is a flowchart illustrating the control method for the heat pump unit provided by the present invention;

[0048] Figure 3 This is a schematic diagram of the control device for the heat pump unit provided by the present invention;

[0049] Figure 4 This is a schematic diagram of the structure of the electronic device provided by the present invention.

[0050] Figure label:

[0051] 1. Indoor heat exchanger; 2. Outdoor heat exchanger; 3. Compressor; 31. Enthalpy-increasing port; 32. Inlet port; 33. Exhaust port; 34. Flash evaporation device; 35. First one-way valve; 5. Four-way valve; 6. Electronic expansion valve;

[0052] 7. First heating branch; 71. Heat storage device; 72. First control valve; 73. First temperature sensor; 74. Second temperature sensor;

[0053] 8. Second heating branch; 81. Enthalpy-increasing heat exchanger; 82. Enthalpy-increasing control valve; 83. Enthalpy-increasing auxiliary circuit;

[0054] 9. Third heating branch; 91. Recirculation heat exchanger; 92. Second control valve; 93. Recirculation auxiliary line; 94. Recirculation control valve; 10. Refrigeration branch; 101. Second check valve; 110. Acquisition module; 120. Control module. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0056] The following description, with reference to the accompanying drawings, illustrates the heat pump unit, its control method, and its control device provided by this invention. It should be noted that the control method and control device proposed in this invention are implemented using the heat pump unit provided in this invention as a structural unit.

[0057] like Figure 1 As shown, the heat pump unit according to the first aspect of the present invention includes an indoor heat exchanger 1, an electronic expansion valve 6, an outdoor heat exchanger 2, a four-way valve 5, and a compressor 3, and also includes refrigerant pipes, wherein the refrigerant pipes include a suction branch (not shown in the figure), a first heating branch 7, a second heating branch 8, and a third heating branch 9, etc.

[0058] Specifically, the indoor heat exchanger 1, the electronic expansion valve 6, the outdoor heat exchanger 2, the four-way valve 5, and the compressor 3 are connected by refrigerant pipes, wherein the four-way valve 5 and the suction port 32 of the compressor 3 are connected by a suction branch.

[0059] There are three parallel heating branches between the indoor heat exchanger 1 and the outdoor heat exchanger 2. The three heating branches are the first heating branch 7, the second heating branch 8 and the third heating branch 9. Each of the three heating branches is equipped with a first one-way valve 35 that flows towards the outdoor heat exchanger 2. The electronic expansion valve 6 is connected in series with the second heating branch 8 and the third heating branch 9 and in parallel with the first heating branch 7. That is, the second heating branch 8 and the third heating branch 9 pass through the electronic expansion valve 6 after they merge, and the first heating branch 7 is connected in parallel with the electronic expansion valve 6.

[0060] The first heating branch 7 is provided with a first control valve 72 and a heat storage device 71 in sequence, and the heat storage device 71 is thermally coupled to the intake branch.

[0061] The second heating branch 8 is equipped with a thermally coupled enthalpy-increasing heat exchanger 81 and an enthalpy-increasing auxiliary branch 83. The two ends of the enthalpy-increasing auxiliary branch 83 are respectively connected to the enthalpy-increasing port 31 of the second heating branch 8 and the compressor 3. An enthalpy-increasing control valve 82 is provided on the enthalpy-increasing auxiliary branch 83.

[0062] The third heating branch 9 is equipped with a thermally coupled return auxiliary line 93 and a return heat exchanger 91. The two ends of the return auxiliary line 93 are connected to the third heating branch 9 and the suction branch, respectively. The third heating branch 9 is also equipped with a second control valve 92, and the return auxiliary line 93 is equipped with a return control valve 94.

[0063] The heat pump unit according to the embodiments of the present invention is designed to solve the problem that the heat pump unit cannot generate high heat under extreme conditions in frigid regions. Its specific working principle is as follows: In heating mode, if the outdoor environment of the area where the heat pump unit is located is a frigid region, the heat pump unit can select at least one of the first heating branch 7, the second heating branch 8 and the third heating branch 9 to be turned on and operated according to the outdoor ambient temperature and the target outlet water temperature set by the user, so as to achieve the purpose of generating high heat in frigid regions.

[0064] The purpose of the first heating branch 7 is to use the heat storage device 71 to recover the waste heat of the high-temperature refrigerant flowing out of the indoor heat exchanger 1 (i.e., condenser), and further use the heat recovered in the heat storage device 71 to heat the refrigerant on the suction side (i.e. suction branch) of the compressor 3, thereby increasing the suction superheat of the compressor 3, and thus ensuring the dryness and temperature of the refrigerant on the suction side. This reduces the power consumption of the compressor 3 while also generating high heat.

[0065] The purpose of the second heating branch 8 is to use the gas injection enthalpy enhancement device (including the enthalpy enhancement heat exchanger 81, the enthalpy enhancement auxiliary line 83, and the enthalpy enhancement control valve 82) to achieve the purpose of gas injection enthalpy enhancement for the heat pump unit. On the one hand, the gas injection enthalpy enhancement device can subcool the high-temperature refrigerant flowing out of the indoor heat exchanger 1 (i.e., the condenser), thereby improving the heat exchange efficiency and effect of the outdoor heat exchanger 2, that is, achieving the purpose of enthalpy enhancement; on the other hand, the gas injection enthalpy enhancement device can increase the discharge volume of the compressor 3, reduce the discharge temperature, and enhance the heating capacity, so that the heat pump air conditioner can provide sufficient heating capacity even at low ambient temperatures, that is, achieving the purpose of gas injection.

[0066] The purpose of the third heating branch 9 is to use the return heat exchanger 91 and the return auxiliary branch 93 to return a portion of the high-temperature refrigerant flowing out of the indoor heat exchanger 1 (i.e., the condenser) to the suction side of the compressor 3 (i.e., the suction branch). At this time, the gas-liquid mixed low-temperature refrigerant flowing out of the outdoor heat exchanger 2 mixes with the gaseous high-temperature refrigerant flowing out of the return auxiliary branch 93 and flows into the suction branch. At this time, the remaining liquid refrigerant in the suction branch is almost completely evaporated into gaseous refrigerant due to the influence of the return gaseous high-temperature refrigerant, thereby ensuring the dryness and sensible heat of the refrigerant on the suction side of the compressor 3, and further improving the heating efficiency of the heat pump system.

[0067] In summary, the first heating branch 7, the second heating branch 8, and the third heating branch 9 can all serve to assist the heat pump unit in generating high heat. Therefore, when the outdoor ambient temperature is low and the user requires a high outlet water temperature, at least one of the first heating branch 7, the second heating branch 8, and the third heating branch 9 can be turned on and put into operation to achieve the purpose of generating high heat in a low-temperature environment.

[0068] Furthermore, as the outdoor ambient temperature continues to decrease, in order to achieve the purpose of generating high heat from the heat pump unit, the controller can sequentially control the first heating branch 7, the second heating branch 8, and the third heating branch 9 to start and operate. That is, depending on the range of the outdoor ambient temperature and the range of the user-preset target outlet water temperature, the heat pump unit can select different starting sequences and different numbers of the first heating branch 7, the second heating branch 8, and the third heating branch 9 to combine them to achieve the purpose of generating high heat in a low-temperature environment.

[0069] It should be noted that the above-mentioned "selecting at least one of the first heating branch 7, the second heating branch 8, and the third heating branch 9 to be turned on and operated" refers to the components on the heating branch being turned on and operated. For example, "selecting the first heating branch 7 to be turned on and operated" means controlling the first control valve 72 on the first heating branch 7 to be turned on and controlling the heat storage device 71 to store heat; "selecting the second heating branch 8 to be turned on and operated" means controlling the enthalpy increase control valve 82 on the second heating branch 8 to be turned on and controlling the enthalpy increase heat exchanger 81 to subcool; "selecting the third heating branch 9 to be turned on and operated" means controlling the second control valve 92 and the return control valve 94 on the third heating branch 9 to be turned on and controlling the return auxiliary line 93 to deliver gaseous high-temperature refrigerant to the suction branch, while controlling the loop heat exchanger to subcool.

[0070] In related technologies, based on the temperature-limited operating conditions of compressors on the market, when the refrigerant return gas temperature is below -40℃, the viscosity coefficient of the compressor oil increases after mixing with the low-temperature refrigerant. This requires the compressor heating belt to heat the oil for more than 120 minutes before the oil temperature can rise for startup, resulting in excessively long startup times and increased user costs. Furthermore, when existing heat pump units operate in heating mode in ultra-low temperature environments (e.g., outdoor ambient temperatures below -30℃), the evaporator-side return gas temperature reaches a maximum of -30℃, making it impossible to guarantee the dryness of the refrigerant in the return gas. Additionally, excessively low return gas refrigerant temperatures can easily increase compressor power consumption and cause excessively low exhaust temperatures.

[0071] Therefore, in the harsh climate of frigid regions, the existing heat pump units have limited heat production capacity and low energy efficiency. The units can only rely on the energy storage electric heating water tank to maintain heating, and the heat production capacity and energy efficiency of the units themselves cannot meet the actual needs.

[0072] In summary, to address the technical deficiencies in the aforementioned related technologies, this invention provides a heat pump unit with three heating branches, each consisting of a heat storage device 71, a gas injection enthalpy enhancement device, and a reflux device (reflux auxiliary path 93, reflux heat exchanger 91, and reflux control valve 94). The heat storage device 71 utilizes waste heat to increase the suction superheat of the compressor 3, ensuring the refrigerant dryness and temperature on the suction side. The gas injection enthalpy enhancement device subcools the high-temperature refrigerant flowing out of the indoor heat exchanger 1 and increases the discharge volume of the compressor 3, reducing the discharge temperature and enhancing heating capacity. The reflux device returns a portion of the high-temperature refrigerant flowing out of the indoor heat exchanger 1 to the suction side of the compressor 3, ensuring the refrigerant dryness and sensible heat on the suction side of the compressor 3.

[0073] As shown above, all three heating branches can assist the heat pump unit in generating high heat in low-temperature environments. Thus, when the outdoor ambient temperature is low and the user requires a high outlet water temperature, at least one of the first heating branch 7, the second heating branch 8, and the third heating branch 9 can be turned on and put into operation to achieve the purpose of generating high heat in low-temperature environments.

[0074] like Figure 1 As shown, according to some embodiments of the present invention, the inlet and outlet of the heat storage device 71 are respectively provided with a first temperature sensor 73 and a second temperature sensor 74, and the first control valve 72 is a temperature-sensing control valve and is connected to the first temperature sensor 73 and the second temperature sensor 74 respectively.

[0075] In this way, the first temperature sensor 73 can detect the refrigerant temperature at the inlet of the heat storage device 71, and the second temperature sensor 74 can detect the refrigerant temperature at the outlet of the heat storage device 71. The difference between the inlet and outlet refrigerant temperatures can reflect the heat storage level of the heat storage device 71. It can also be understood that since the heat storage level of the heat storage device 71 is closely related to the refrigerant flow rate in the first heating branch 7, that is, the greater the refrigerant flow rate, the greater the heat storage level of the heat storage device 71. At this time, the heating effect of the heat storage device 71 on the intake branch is also better. Therefore, by controlling the opening of the temperature sensor control valve, the refrigerant flow rate in the first heating branch 7 can be monitored and adjusted in real time, thereby realizing the adjustment of the heat storage level of the heat storage device 71, and thus the adjustment of the heating effect of the heat storage device 71 on the intake branch.

[0076] like Figure 1 As shown, according to some embodiments of the present invention, a flash evaporation device 34 is also provided on the intake heating branch, and the flash evaporation device 34 is located downstream of the third heating branch 9. In this way, the flash evaporation device 34 provides supplementary gas to the compressor 3 in the unit. At this time, the refrigerant is in the state of high temperature gas. After mixing with the compressor oil, it can drive the compressor oil to heat up, thereby reducing the power consumption under ultra-low temperature conditions and also reducing the start-up time of the unit.

[0077] According to some embodiments of the present invention, a refrigeration branch 10 is further provided between the indoor heat exchanger 1 and the electronic expansion valve 6, and a second one-way valve 101 is provided on the refrigeration branch 10 to flow toward the side of the indoor heat exchanger 1.

[0078] It is understandable that when the heat pump unit is operating in cooling mode, all the refrigerant flows through the cooling branch 10; when the heat pump unit is operating in heating mode, the refrigerant flows through at least one of the first heating branch 7, the second heating branch 8, and the third heating branch 9.

[0079] The control method, control device, and air conditioner of the heat pump unit proposed in this invention are described below with reference to the accompanying drawings. Before providing a detailed description of the embodiments of this invention, the overall application scenario is first described. The control method, control device, electronic equipment, and computer-readable storage medium of the heat pump unit of this invention can be applied locally to the heat pump unit, to cloud platforms in the Internet field, or to other types of cloud platforms in the Internet field, or to third-party devices. These third-party devices may include various types such as mobile phones, tablets, laptops, in-vehicle computers, and other smart terminals.

[0080] The following description uses only the control method applicable to heat pump units as an example. It should be understood that the control method of this embodiment can also be applied to cloud platforms and third-party devices.

[0081] like Figure 2 As shown, a control method for a heat pump unit according to a second aspect embodiment of the present invention includes:

[0082] Step S1: When the heat pump unit is in heating mode, obtain the outdoor ambient temperature and the target outlet water temperature of the heat pump unit.

[0083] Step S2: Generate control logic based on the outdoor ambient temperature and / or the target outlet water temperature, and control the working status and operating parameters of the heat storage device 71, the enthalpy-increasing heat exchanger 81 and the reflux heat exchanger 91 according to the control logic.

[0084] It is understood that the above-mentioned control of the working state and working parameters of the heat storage device 71, the enthalpy-increasing heat exchanger 81 and the reflux heat exchanger 91 according to the control logic refers to controlling at least one of the first heating branch 7, the second heating branch 8 and the third heating branch 9 to start and work according to the control logic, and adjusting its working parameters.

[0085] According to some embodiments of the present invention, the steps of generating control logic based on the outdoor ambient temperature and / or the target outlet water temperature, and controlling the operating state and operating parameters of the heat storage device 71, the enthalpy-increasing heat exchanger 81, and the reflux heat exchanger 91 according to the control logic specifically include:

[0086] When the outdoor ambient temperature is within the first outdoor temperature zone, the first control valve 72, the enthalpy-increasing control valve 82, the second control valve 92, and the reflux control valve 94 are all closed to keep the heat storage device 71, the enthalpy-increasing heat exchanger 81, and the reflux heat exchanger 91 in a closed state. The first outdoor temperature zone is greater than zero.

[0087] Thus, when the outdoor ambient temperature is within the first outdoor temperature range, the outdoor ambient temperature is normal and not considered a low-temperature or frigid condition. Therefore, the heat pump unit can start and provide heating normally without assistance. That is, the controller controls the first control valve 72, the enthalpy-increasing control valve 82, the second control valve 92, and the return control valve 94 to close, so that the heat storage device 71, the enthalpy-increasing heat exchanger 81, and the return heat exchanger 91 are all kept closed. At this time, the refrigerant flows normally through the second heating branch 8 and passes through the electronic expansion valve 6 and the outdoor heat exchanger 2 in sequence before returning to the compressor 3. For example, the first outdoor temperature range can be from 0°C to 20°C, and this invention does not impose any special limitations.

[0088] According to other embodiments of the present invention, the steps of generating control logic based on the outdoor ambient temperature and / or the target outlet water temperature, and controlling the operating state and operating parameters of the heat storage device 71, the enthalpy-increasing heat exchanger 81, and the reflux heat exchanger 91 according to the control logic specifically include:

[0089] When the outdoor ambient temperature is within the second outdoor temperature range, the enthalpy-increasing control valve 82 is opened to put the enthalpy-increasing heat exchanger 81 into operation. The operating status and parameters of the heat storage device 71 and the reflux heat exchanger 91 are controlled according to the range of the target outlet water temperature. The second outdoor temperature range is less than zero.

[0090] Thus, when the outdoor ambient temperature is in the second outdoor temperature zone, the outdoor ambient temperature is relatively low. At this time, the heat pump unit alone cannot achieve the purpose of generating high heat by simply operating normally. Therefore, the controller controls the enthalpy increase control valve 82 to open, so that the enthalpy increase heat exchanger 81 is in working condition, thereby playing a role in replenishing gas and increasing enthalpy, and maintaining a stable heat output of the heat pump unit. For example, the second outdoor temperature zone can be from -25°C to 0°C, and the present invention does not impose any special limitations.

[0091] Furthermore, the steps of controlling the operating status and parameters of the heat storage device 71 and the reflux heat exchanger 91 according to the target outlet water temperature range specifically include:

[0092] When the target outlet water temperature is in the first outlet water temperature zone, control the first control valve 72, the second control valve 92 and the return control valve 94 to close so that the heat storage device 71 and the return heat exchanger 91 are both kept in the closed state.

[0093] Thus, after the enthalpy-increasing control valve 82 is opened, if the user-preset target outlet water temperature is not high, there is no need to turn on the heat storage device 71 and the reflux heat exchanger 91. The user's needs can be met simply by using the already activated gas replenishment enthalpy-increasing device. For example, the first outlet water temperature range can be 20°C to 35°C, and the present invention does not impose any special limitations on this.

[0094] Furthermore, the steps of controlling the operating status and parameters of the heat storage device 71 and the reflux heat exchanger 91 according to the target outlet water temperature range specifically include:

[0095] When the target outlet water temperature is in the second outlet water temperature zone, the first control valve 72 is opened to put the heat storage device 71 into operation, and the second control valve 92 and the return control valve 94 are both closed to keep the return heat exchanger 91 closed; or, the second control valve 92 and the return control valve 94 are both opened to keep the return heat exchanger 91 open, and the first control valve 72 is closed to keep the heat storage device 71 closed.

[0096] The first outlet water temperature zone is smaller than the second outlet water temperature zone.

[0097] Thus, if the user's preset target outlet water temperature is high, the heating effect of the heat pump unit can be further improved by activating at least one of the heat storage device 71 and the reflux heat exchanger 91, thereby meeting the user's water demand. For example, the second outlet water temperature zone can be from 35°C to 60°C, and the present invention does not impose any special limitations on this.

[0098] According to further embodiments of the present invention, the steps of generating control logic based on the outdoor ambient temperature and / or the target outlet water temperature, and controlling the operating state and operating parameters of the heat storage device 71, the enthalpy-increasing heat exchanger 81, and the reflux heat exchanger 91 according to the control logic, specifically include:

[0099] Based on the outdoor ambient temperature being in the third outdoor temperature zone, the first control valve 72, the enthalpy increase control valve 82, the second control valve 92 and the reflux control valve 94 are all opened so that the heat storage device 71, the enthalpy increase heat exchanger 81 and the reflux heat exchanger 91 are all in working condition. The third outdoor temperature zone is smaller than the second outdoor temperature zone.

[0100] After confirming that the first control valve 72, the enthalpy increase control valve 82, the second control valve 92 and the return flow control valve 94 are all open, the suction temperature of the compressor 3 is obtained.

[0101] Based on the intake air temperature and the outdoor ambient temperature, the opening degree of at least one of the first control valve 72, the enthalpy increase control valve 82, the reflux control valve 94, and the electronic expansion valve 6 is controlled and adjusted.

[0102] In this embodiment, when the outdoor ambient temperature is in the third outdoor temperature zone (e.g., -40°C to -60°C), it indicates that the outdoor temperature is extremely low and the climate is frigid. In order to ensure that the heat pump unit can continue to generate high heat in this extremely low temperature environment, the controller will control the first control valve 72, the enthalpy increase control valve 82, the second control valve 92 and the return control valve 94 to open. At this time, the refrigerant flowing out from the indoor heat exchanger 1 passes through the heat storage device 71 of the first heating branch 7, the gas replenishment enthalpy increase device of the second heating branch 8 and the return device of the third heating branch 9 to assist the unit in generating high heat.

[0103] It should be noted that in the above embodiments, the compressor 3 of the heat pump unit needs to run at a low frequency for a certain period of time during the initial start-up phase to achieve the pressure equalization process of the refrigerant in the system. During the low-frequency operation, the first control valve 72, the enthalpy increase control valve 82, the second control valve 92 and the return flow control valve 94 are also opened according to the preset initial opening degree. After the compressor 3 runs at a low frequency for a period of time, the compressor 3 continues to increase the frequency until it reaches the specified frequency.

[0104] Furthermore, during the process of compressor 3 initially operating at low frequency and then increasing its frequency to the specified frequency, the opening degrees of the first control valve 72, the enthalpy-increasing control valve 82, the second control valve 92, and the return flow control valve 94 are not constant but need to be adjusted according to changes in suction temperature and outdoor ambient temperature. In this way, on the one hand, adaptive changes can be made in a timely manner when the operating conditions change to ensure the unit's high heat production performance in extremely low temperature environments; on the other hand, the amount of refrigerant used to assist compressor 3 in operation and the amount of refrigerant used for heating and hot water production can be coordinated and allocated within the unit, thereby achieving a balance between ensuring stable operation of compressor 3 and meeting the user's water demand, and further improving the user experience while ensuring the unit's high heat production in extremely low temperature environments.

[0105] In some specific embodiments of the present invention, the step of controlling and adjusting the opening degree of at least one of the first control valve 72, the enthalpy increase control valve 82, the reflux control valve 94, and the electronic expansion valve 6 according to the intake temperature and the outdoor ambient temperature specifically includes:

[0106] When the difference between the intake temperature and the outdoor ambient temperature is less than or equal to the first set temperature difference, the opening degree of the first control valve 72 is increased to the first heat storage opening degree, the opening degree of the return control valve 94 is increased to the first return opening degree, and the opening degree of the electronic expansion valve 6 is decreased to the first expansion opening degree.

[0107] It is understandable that when the difference between the suction temperature and the outdoor ambient temperature is too small, it indicates that the suction temperature is low. At this time, it is necessary to control the opening of the first control valve 72 to increase the first heat storage opening, thereby increasing the heat storage capacity of the heat storage device 71 and enhancing the heating effect of the heat storage device 71 on the suction branch. It is also necessary to control the opening of the return control valve 94 to increase the first return opening, thereby increasing the amount of gaseous high-temperature refrigerant returning to the suction branch, enhancing the dryness of the refrigerant in the suction branch and eliminating its sensible heat. It is also necessary to control the opening of the electronic expansion valve 6 to decrease the amount of refrigerant on the outdoor heat exchanger 2 side, thereby reducing the operating burden of the compressor 3.

[0108] For example, the first set temperature difference can be 5°C, and the present invention does not impose any special limitations on this.

[0109] In other specific embodiments of the present invention, the step of controlling the opening degree of at least one of the first control valve 72, the enthalpy increase control valve 82, the reflux control valve 94, and the electronic expansion valve 6 according to the intake temperature and the outdoor ambient temperature further includes:

[0110] When the difference between the intake temperature and the outdoor ambient temperature is greater than or equal to the second set temperature difference, the opening degree of the first control valve 72 is reduced to the second heat storage opening degree, the opening degree of the return control valve 94 is reduced to the second return opening degree, and the opening degree of the electronic expansion valve 6 is increased to the second expansion opening degree.

[0111] It is understandable that when the difference between the suction temperature and the outdoor ambient temperature is too large, it indicates that the suction temperature is high. At this time, the unit does not need too much refrigerant to assist the compressor 3. Therefore, more refrigerant can be used for the heating and hot water production function of the unit. At this time, the opening of the first control valve 72 is reduced to the second heat storage opening, thereby reducing the heat storage capacity of the heat storage device 71 and weakening the heating effect of the heat storage device 71 on the suction branch. It is also necessary to control the opening of the return control valve 94 to reduce the amount of gaseous high-temperature refrigerant returning to the suction branch to avoid overheating of the compressor 3. It is also necessary to control the opening of the electronic expansion valve 6 to increase the amount of refrigerant on the outdoor heat exchanger 2 side, thereby increasing the proportion of refrigerant used for heating and hot water production in the unit and providing more hot water for users.

[0112] For example, the second set temperature difference can be 20°C, and the present invention does not impose any special limitations on this.

[0113] In some other specific embodiments of the present invention, when the difference between the intake temperature and the outdoor ambient temperature is greater than a first set temperature difference and less than a second set temperature difference, all valves in the unit are kept at their original opening degree.

[0114] According to some embodiments of the present invention, after the step of controlling the opening degree of at least one of the first control valve 72, the enthalpy increase control valve 82, the reflux control valve 94, and the electronic expansion valve 6 based on the intake temperature and the outdoor ambient temperature, the method further includes:

[0115] After the heat pump unit has been running for at least a preset time, obtain the adjusted difference between the current suction temperature and the outdoor ambient temperature.

[0116] According to the adjustment, if the difference is less than or equal to the first set temperature difference or greater than or equal to the second set temperature difference, control the reflux control valve 94 and the electronic expansion valve 6 to restore to the initial reflux valve opening and the initial expansion valve opening, respectively.

[0117] The actual exhaust superheat and target exhaust superheat of the compressor 3 are obtained, and the opening of the electronic expansion valve 6 is controlled and adjusted according to the actual exhaust superheat and target exhaust superheat.

[0118] In this embodiment, after adjusting the opening of at least one of the first control valve 72, enthalpy control valve 82, reflux control valve 94, and electronic expansion valve 6, all valves are maintained at the current adjusted opening. After the unit has been running for at least a preset time, the adjusted difference between the current suction temperature and the outdoor ambient temperature is obtained, and it is determined whether the adjusted difference meets the preset temperature condition. If it does, no operation is performed, and all valves are maintained at the current adjusted opening. If it does not meet the condition, all valves in the unit are restored to their initial valve opening, and the electronic expansion valve 6 is further adjusted according to the superheat of the compressor 3 until the suction temperature meets the preset temperature condition.

[0119] Specifically, the steps for controlling and adjusting the opening of the electronic expansion valve 6 based on the actual exhaust superheat and the target exhaust superheat include:

[0120] When the actual exhaust superheat is greater than the target exhaust superheat, the opening of the electronic expansion valve 6 is increased by the first variable opening.

[0121] When the actual exhaust superheat is less than the target exhaust superheat, the opening of the electronic expansion valve 6 is reduced by the second variable opening.

[0122] It is understandable that when the actual exhaust superheat is high, the opening of the electronic expansion valve 6 is increased to increase the proportion of refrigerant used for heating and hot water production in the unit, and to reduce the proportion of refrigerant used for auxiliary compressor 3 in the unit, thereby ensuring the user's heating needs; when the actual exhaust superheat is low, the opening of the electronic expansion valve 6 is decreased to increase the proportion of refrigerant used for auxiliary compressor 3 in the unit, and to reduce the proportion of refrigerant used for heating and hot water production in the unit, thereby ensuring the unit's performance of producing high heat at extremely low temperatures.

[0123] Furthermore, the initial reflux valve opening, the initial expansion valve opening, and the target exhaust superheat are all obtained based at least on the outdoor ambient temperature.

[0124] A specific embodiment of the control method for the heat pump unit of the present invention is described below with reference to the accompanying drawings.

[0125] like Figure 1 As shown, the heat pump unit includes an indoor heat exchanger 1, a compressor 3 and its enthalpy-increasing port 31, suction port 32 and exhaust port 33, an outdoor heat exchanger 2, a flash evaporation device 34, a four-way valve 5, a heat storage device 71, an enthalpy-increasing heat exchanger 81, a reflux heat exchanger 91, a first control valve 72, a first temperature sensor 73, a second temperature sensor 74, an enthalpy-increasing control valve 82, an enthalpy-increasing auxiliary circuit 83, a second control valve 92, a reflux auxiliary circuit 93, a reflux control valve 94, an electronic expansion valve 6, a first one-way valve 35, a second one-way valve 101, a first heating branch 7, a second heating branch 8, a third heating branch 9 and a cooling branch 10.

[0126] The various heating modes of heat pump units are described below:

[0127] (1) In the first heating mode, the outdoor ambient temperature is 0℃~20℃ and the target outlet water temperature is 20℃~60℃. At this time, the first control valve 72, the enthalpy increase control valve 82, the second control valve 92 and the return control valve 94 are all closed so that the heat storage device 71, the enthalpy increase heat exchanger 81 and the return heat exchanger 91 are all kept closed. All the refrigerant in the unit flows through the second heating branch 8 and is determined according to the outdoor ambient temperature and the target outlet water requirements set by the user. In this mode, there is no need to turn on the enhanced heat exchange and ordinary heating can be performed.

[0128] (2) In the second heating mode, the outdoor ambient temperature is -25℃ to 0℃, and the target outlet water temperature is 20℃ to 35℃. At this time, the first control valve 72, the second control valve 92, and the return control valve 94 are all closed so that the heat storage device 71 and the return heat exchanger 91 are kept closed. All the refrigerant in the unit flows through the second heating branch 8, and at the same time, the enthalpy increase control valve 82 is opened so that the enthalpy increase auxiliary branch 83 and the enthalpy increase heat exchanger 81 are working. As a result, as the outdoor ambient temperature decreases, if the user sets a low outlet water requirement, the unit cannot produce high heat output by relying solely on the normal mode. It is necessary to turn on the enthalpy increase device to maintain a stable heat output.

[0129] (3) In the third heating mode, the outdoor ambient temperature is -25℃ to 0℃, and the target outlet water temperature is 35℃ to 60℃. At this time, the enthalpy increase control valve 82 and the first control valve 72 are opened to make the enthalpy increase heat exchanger 81 and the heat storage device 71 work, and the second control valve 92 and the return control valve 94 are closed to keep the return heat exchanger 91 closed. The refrigerant in the unit flows through the first heating branch 7 and the second heating branch 8. Taking the temperature detected by the first temperature sensor 73 as T1 and the temperature detected by the second temperature sensor 74 as T2 as an example, the temperature sensing control valve controls the refrigerant flow rate in the first heating branch 7 according to the formula (T1-T2=5℃), thereby controlling the heat exchange temperature between the heat storage device 71 and the suction branch. As the outdoor ambient temperature decreases and the user's water output requirements increase, the unit not only needs to activate the enthalpy-increasing mode, but also needs to use the waste heat recovery device to control and heat the return gas pipeline. This helps to ensure the dryness of the return gas of compressor 3 and increase its temperature, thereby reducing the power consumption of compressor 3 while also generating high heat.

[0130] (4) In the fourth heating mode, the outdoor ambient temperature is -40℃ to -25℃, and the target outlet water temperature is 20℃ to 60℃. During the initial start-up of the unit, the compressor 3 first runs at a low frequency for 10 minutes and then continuously increases the frequency to the specified frequency. During the process of the compressor 3 changing from low-frequency operation to frequency increase to the specified frequency, the first control valve 72, the enthalpy increase control valve 82, the second control valve 92 and the reflux control valve 94 are all opened to keep the heat storage device 71, the enthalpy increase heat exchanger 81 and the reflux heat exchanger 91 working. The initial opening degree of the reflux control valve 94 is set to A, the initial opening degree of the electronic expansion valve 6 is set to B, the flash device 34 is controlled to start synchronously, and the oil temperature detection value in the middle of the compressor 3 is set to T℃. At this time, A=300, B=100 and T=20. Furthermore, taking the temperature detected by the first temperature sensor 73 as T1 and the temperature detected by the second temperature sensor 74 as T2 as an example, the temperature control valve controls the refrigerant flow rate in the first heating branch 7 according to the formula (T1-T2=5℃), thereby controlling the heat exchange temperature between the heat storage device 71 and the suction branch.

[0131] The return auxiliary path 93 is a short-flow path. The opening degree of the return control valve 94, 300, is equivalent to 3 / 4 of its overall valve opening. This avoids the need for rapid pressure equalization, thus preventing compressor 3 from drawing liquid due to excessive valve opening. The purpose of setting the opening degree of the electronic expansion valve 6 to 100 is to slowly regulate the pressure on the evaporator side, preventing a rapid pressure drop and insufficient dryness of the generated gaseous refrigerant. In addition, the oil temperature in the middle of compressor 3 is set to 20℃ to prevent the oil viscosity from increasing due to excessively low temperature, thus avoiding malfunctions caused by excessive power consumption.

[0132] It is understandable that the refrigerant in the unit is simultaneously distributed to the first heating branch 7, the second heating branch 8, and the third heating branch 9. Furthermore, during the process of compressor 3 initially operating at low frequency and then increasing its frequency to the specified frequency, the openings of the first control valve 72, the enthalpy-increasing control valve 82, the second control valve 92, and the return flow control valve 94 are not constant but need to be adjusted according to changes in the suction temperature and the outdoor ambient temperature. Taking the suction temperature of compressor 3 as Ts and the outdoor ambient temperature as Tao as an example, the specific adjustment process is as follows:

[0133] (4.1) Ts-Tao≤5℃: The temperature-sensing control valve controls the refrigerant flow in the first heating branch 7 according to the formula (T1-T2=10℃). The return flow control valve 94 is increased by 5pls / min, and the electronic expansion valve 6 is decreased by 3pls / min. After the above opening adjustment is completed, the unit maintains the adjusted opening and continues to run for 20 minutes before judging the difference between the suction temperature Ts and the outdoor ambient temperature Tao.

[0134] When the intake temperature Ts and the outdoor ambient temperature Tao do not meet the condition 5℃<(Ts-Tao)<20℃, the control valve 94 and the electronic expansion valve 6 both return to their initial valve openings. The initial valve opening Y1 is calculated using the following formula:

[0135] Y1 = 1 / 2(maximum valve opening - minimum valve opening) + C1*Tao.

[0136] After the reflux control valve 94 and the electronic expansion valve 6 are restored to their initial valve openings, the actual exhaust superheat of the compressor 3 and the target exhaust superheat are further compared, and the opening of the electronic expansion valve 6 is adjusted according to the comparison result. Specifically, when the actual exhaust superheat is less than the target exhaust superheat, the opening of the electronic expansion valve 6 is reduced by 5 pls / min; when the actual exhaust superheat is equal to the target exhaust superheat, the electronic expansion valve 6 maintains its current opening; when the actual exhaust superheat is greater than the target exhaust superheat, the opening of the electronic expansion valve 6 is increased by 20 pls / min. The empirical formula for calculating the target exhaust superheat is: Target exhaust superheat = {1 / 2*(maximum operating frequency of compressor 3 - Tao) + 0.1*(current frequency of compressor 3) + Tao / (Tao+5)*(Two-55)}*0.5, where Two is the target outlet water temperature.

[0137] (4.2) 5℃<Ts-Tao<20℃: All valves maintain their current opening. When the difference between the intake temperature and the outdoor ambient temperature is about 5℃, the intake refrigerant maintains a high degree of dryness. As the temperature difference increases, the intake refrigerant also has a certain degree of superheat. It is understandable that a certain degree of superheat is a prerequisite for achieving high exhaust and high capacity.

[0138] (4.3)20℃≤Ts-Tao: The temperature sensing control valve controls the refrigerant flow in the first heating branch 7 according to the formula (T1-T2=5℃), the enthalpy increase control valve 82 maintains the current opening, the opening of the return flow control valve 94 is reduced by 5pls / min, and the opening of the electronic expansion valve 6 is increased by 3pls / min. After the above opening adjustment is completed, the unit maintains the adjusted opening and continues to run for 10 minutes before judging the difference between the suction temperature Ts and the outdoor ambient temperature Tao again.

[0139] When the intake temperature Ts and the outdoor ambient temperature Tao do not meet the condition 5℃<(Ts-Tao)<20℃, the control valve 94 and the electronic expansion valve 6 both return to their initial valve openings. The initial valve opening Y2 is calculated using the following formula:

[0140] Y2 = 1 / 2(maximum valve opening - minimum valve opening) + C2 * Tao.

[0141] After the reflux control valve 94 and the electronic expansion valve 6 are restored to their initial valve openings, the actual exhaust superheat of the compressor 3 and the target exhaust superheat are further compared, and the opening of the electronic expansion valve 6 is adjusted according to the comparison result. Specifically, when the actual exhaust superheat is less than the target exhaust superheat, the opening of the electronic expansion valve 6 is reduced by 5 pls / min; when the actual exhaust superheat is equal to the target exhaust superheat, the electronic expansion valve 6 maintains its current opening; when the actual exhaust superheat is greater than the target exhaust superheat, the opening of the electronic expansion valve 6 is increased by 5 pls / min. The empirical formula for calculating the target exhaust superheat is: Target exhaust superheat = {1 / 2*(maximum operating frequency of compressor 3 - Tao) + 0.1*(current frequency of compressor 3) + Tao / (Tao+5)*(Two-55)}*0.55, where Two is the target outlet water temperature.

[0142] In summary, the heat pump system and its control method according to embodiments of the present invention, by combining the heat pump system principle of parallel plate heat exchangers with optimized control logic of three-chamber split flow, helps to solve the problem of heat pumps failing to generate high heat under ultra-low temperature outdoor ambient temperatures in frigid regions. Its specific advantages are as follows:

[0143] 1. When the compressor oil is exposed to ultra-low ambient temperatures, its viscosity increases due to the low ambient temperature. Preheating with the compressor's electric heating element increases user costs and prolongs the oil heating process, easily triggering power alarms. This invention uses a simple flow path for rapid pressure equalization to establish a pressure ratio. A flash evaporation device 34 provides supplementary gas to the compressor. The refrigerant in this state is a high-temperature gas, which, when mixed with the compressor oil, can raise the oil temperature. This reduces the need for the unit to rely on the compressor heating element for heating before startup under ultra-low temperature conditions, reducing power consumption and startup time. The return gas, in its high-temperature gaseous state, rapidly raises the compressor oil temperature, further reducing startup time and providing safe operation for the compressor in ultra-low ambient temperatures.

[0144] 2. Under ultra-low temperature outdoor ambient temperature, if there is too much two-phase refrigerant in the outdoor heat exchanger 2, the return gas may contain gaseous refrigerant with low dryness and low temperature, which is not conducive to the unit generating high heat. This invention applies the parallel plate heat exchanger method and waste heat recovery technology to the air source heat pump system. Its main function is to increase the superheat of the compressor 3 suction gas and ensure the dryness of the refrigerant on the suction side. In this way, by combining the parallel plate heat exchanger system and the waste heat recovery system, this invention can make full use of the heat storage device 71 on the first heating branch 7 to recover and utilize the waste heat of the refrigerant in the indoor heat exchanger 1 while rationally distributing the flow of each path. The gas replenishment and enthalpy enhancement device on the second heating branch 8 ensures that the refrigerant flow of the compressor 3 returns to the replenishment state, preventing excessive overheating that could damage the unit. The return flow device on the third heating branch 9 ensures the dryness and sensible heat of the refrigerant returning to the evaporator side.

[0145] The control device for the heat pump unit provided by the present invention is described below. The control device for the heat pump unit described below can be referred to in correspondence with the control method for the heat pump unit described above.

[0146] like Figure 3 As shown, a control device for a heat pump unit according to a second aspect embodiment of the present invention includes:

[0147] The acquisition module 110 is used to acquire the outdoor ambient temperature and the target outlet water temperature of the heat pump unit when the heat pump unit is in heating mode.

[0148] The control module 120 is used to generate control logic based on the outdoor ambient temperature and / or the target outlet water temperature, and to control the working status and operating parameters of the heat storage device 71, the enthalpy-increasing heat exchanger 81 and the reflux heat exchanger 91 according to the control logic.

[0149] Figure 4 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 4As shown, the electronic device may include a processor 810, a communication interface 820, a memory 830, and a communication bus 840. The processor 810, communication interface 820, and memory 830 communicate with each other via the communication bus 840. The processor 810 can call logic instructions stored in the memory 830 to execute the control method of the heat pump unit described above.

[0150] Furthermore, the logical instructions in the aforementioned memory 830 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0151] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer is able to execute the control method of the heat pump unit described above.

[0152] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to perform the control method of the heat pump unit described above.

[0153] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0154] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0155] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A heat pump unit, characterized by The application relates to a heat pump unit. The heat pump unit comprises an indoor heat exchanger, an electronic expansion valve, an outdoor heat exchanger, a four-way valve and a compressor, wherein the four-way valve is connected with the suction port of the compressor through a suction branch; The indoor heat exchanger and the outdoor heat exchanger are provided with three heating branches in parallel, wherein the three heating branches comprise a first heating branch, a second heating branch and a third heating branch, and each of the three heating branches is provided with a first check valve for flowing to the side of the outdoor heat exchanger; the electronic expansion valve is connected with the second heating branch and the third heating branch in series and connected with the first heating branch in parallel; The first heating branch is provided with a first control valve and a heat storage device in sequence, and the heat storage device is thermally coupled with the suction branch; The second heating branch is provided with a heat-coupled enthalpy-increasing heat exchanger and an enthalpy-increasing auxiliary branch, the two ends of the enthalpy-increasing auxiliary branch are connected with the second heating branch and the enthalpy-increasing port of the compressor respectively, and the enthalpy-increasing auxiliary branch is provided with an enthalpy-increasing control valve; The third heating branch is provided with a heat-coupled backflow auxiliary branch and a backflow heat exchanger, the two ends of the backflow auxiliary branch are connected with the third heating branch and the suction branch respectively, and the third heating branch is further provided with a second control valve, and the backflow auxiliary branch is provided with a backflow control valve.

2. The heat pump unit of claim 1, wherein, The inlet and outlet of the heat storage device are respectively provided with a first temperature sensor and a second temperature sensor, and the first control valve is a temperature-sensing control valve and is connected with the first temperature sensor and the second temperature sensor respectively.

3. The heat pump unit of claim 1, wherein, The suction branch is further provided with a flash device, and the flash device is located downstream of the third heating branch.

4. The heat pump package of any of claims 1-3, wherein, The indoor heat exchanger and the electronic expansion valve are further provided with a refrigeration branch, and the refrigeration branch is provided with a second check valve for flowing to the side of the indoor heat exchanger.

5. A control method for a heat pump unit according to any one of claims 1 to 4, characterized by, The application relates to a heat pump unit. In the case that the heat pump unit is in a heating mode, an outdoor environment temperature and a target outlet water temperature of the heat pump unit are acquired; Control logic is generated according to the outdoor environment temperature and / or the target outlet water temperature, and the working state and working parameter of the heat storage device, the enthalpy-increasing heat exchanger and the backflow heat exchanger are controlled according to the control logic.

6. The control method of a heat pump package according to claim 5, wherein The step of generating control logic according to the outdoor environment temperature and / or the target outlet water temperature and controlling the working state and working parameter of the heat storage device, the enthalpy-increasing heat exchanger and the backflow heat exchanger according to the control logic specifically comprises: In the case that the outdoor environment temperature is in a first outdoor temperature zone, the first control valve, the enthalpy-increasing control valve, the second control valve and the backflow control valve are all controlled to be closed so that the heat storage device, the enthalpy-increasing heat exchanger and the backflow heat exchanger all remain in a closed state; Or, in the case that the outdoor environment temperature is in a second outdoor temperature zone, the enthalpy-increasing control valve is controlled to be opened so that the enthalpy-increasing heat exchanger is in a working state, and the working state and working parameter of the heat storage device and the backflow heat exchanger are controlled according to the interval range of the target outlet water temperature; The first outdoor temperature zone is greater than zero, and the second outdoor temperature zone is less than zero.

7. The control method of a heat pump package according to claim 6, wherein The step of controlling the working state and working parameter of the heat storage device and the return flow heat exchanger according to the target outlet water temperature, specifically comprises: In the case that the target outlet water temperature is in a first outlet water temperature zone, the first control valve, the second control valve and the return flow control valve are all controlled to be closed so that the heat storage device and the return flow heat exchanger are both kept in a closed state; Or, in the case that the target outlet water temperature is in a second outlet water temperature zone, the first control valve is controlled to be opened so that the heat storage device is in a working state, and the second control valve and the return flow control valve are both controlled to be closed so that the return flow heat exchanger is kept in a closed state; Wherein, the first outlet water temperature zone is smaller than the second outlet water temperature zone.

8. The control method of a heat pump package according to claim 6 or 7, characterized by, The step of generating control logic according to the outdoor environment temperature and / or the target outlet water temperature, and controlling the working state and working parameter of the heat storage device, the enthalpy increasing heat exchanger and the return flow heat exchanger according to the control logic, specifically further comprises: In the case that the outdoor environment temperature is in a third outdoor temperature zone, the first control valve, the enthalpy increasing control valve, the second control valve and the return flow control valve are all controlled to be opened so that the heat storage device, the enthalpy increasing heat exchanger and the return flow heat exchanger are all in a working state, wherein the third outdoor temperature zone is smaller than the second outdoor temperature zone; After determining that the first control valve, the enthalpy increasing control valve, the second control valve and the return flow control valve are all opened, the suction temperature of the compressor is acquired; According to the suction temperature and the outdoor environment temperature, the opening degree of at least one of the first control valve, the enthalpy increasing control valve, the return flow control valve and the electronic expansion valve is controlled to be adjusted.

9. The control method of a heat pump package according to claim 8, wherein, The step of controlling the opening degree of at least one of the first control valve, the enthalpy increasing control valve, the return flow control valve and the electronic expansion valve according to the suction temperature and the outdoor environment temperature, specifically comprises: In the case that the difference between the suction temperature and the outdoor environment temperature is less than or equal to a first set temperature difference, the opening degree of the first control valve is controlled to be increased to a first heat storage opening degree, the opening degree of the return flow control valve is controlled to be increased to a first return flow opening degree, and the opening degree of the electronic expansion valve is controlled to be decreased to a first expansion opening degree; Or, in the case that the difference between the suction temperature and the outdoor environment temperature is greater than or equal to a second set temperature difference, the opening degree of the first control valve is controlled to be decreased to a second heat storage opening degree, the opening degree of the return flow control valve is controlled to be decreased to a second return flow opening degree, and the opening degree of the electronic expansion valve is controlled to be increased to a second expansion opening degree.

10. The control method of a heat pump package according to claim 8, wherein After the step of controlling the opening degree of at least one of the first control valve, the enthalpy increasing control valve, the return flow control valve and the electronic expansion valve according to the suction temperature and the outdoor environment temperature, further comprises: After the heat pump unit operates for at least a preset time length, the adjusted difference between the current suction temperature and the outdoor environment temperature is acquired; According to the adjusted difference being less than or equal to a first set temperature difference or being greater than or equal to a second set temperature difference, the return control valve and the electronic expansion valve are respectively restored to an initial return valve opening degree and an initial expansion valve opening degree; An actual exhaust superheat degree and a target exhaust superheat degree of the compressor are obtained, and the opening degree of the electronic expansion valve is adjusted according to the actual exhaust superheat degree and the target exhaust superheat degree.

11. The control method of a heat pump package according to claim 10, wherein The step of adjusting the opening degree of the electronic expansion valve according to the actual exhaust superheat degree and the target exhaust superheat degree specifically includes: In a case where the actual exhaust superheat degree is greater than the target exhaust superheat degree, the opening degree of the electronic expansion valve is increased by a first change opening degree; In a case where the actual exhaust superheat degree is less than the target exhaust superheat degree, the opening degree of the electronic expansion valve is decreased by a second change opening degree.

12. The control method of a heat pump package according to claim 11, wherein, The initial return valve opening degree, the initial expansion valve opening degree and the target exhaust superheat degree are all obtained according to the outdoor environment temperature.

13. A control device for a heat pump unit according to any one of claims 1 to 4, characterized by The method comprises: An obtaining module is configured to obtain an outdoor environment temperature and a target outlet water temperature of the heat pump unit in a case where the heat pump unit is in a heating mode; A control module is configured to generate a control logic according to the outdoor environment temperature and / or the target outlet water temperature, and control working states and working parameters of the heat storage device, the enthalpy increasing heat exchanger and the return heat exchanger according to the control logic.

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