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

Abstract

The invention provides a heat pump system, a control method of the heat pump system and a control device of the heat pump system. The heat pump unit comprises an indoor heat exchanger, an electronic expansion valve, an outdoor heat exchanger, a four-way valve and a compressor, and an air suction branch is arranged between the four-way valve and an air suction port of the compressor. A first heating branch, a second heating branch and a third heating branch which are connected in parallel are arranged between the indoor heat exchanger and the outdoor heat exchanger and are respectively provided with a first one-way valve; a first control valve and a heat storage device thermally coupled with the air suction branch are sequentially arranged on the first heating branch; the second heating branch is provided with an enthalpy-increasing heat exchanger and an enthalpy-increasing auxiliary path which are thermally coupled; the enthalpy-increasing auxiliary path is communicated to an enthalpy-increasing opening of the compressor and is provided with an enthalpy-increasing control valve; the third heating branch is provided with a second control valve, a backflow auxiliary path in thermal coupling and a backflow heat exchanger, and the backflow auxiliary path communicates with the air suction branch and is provided with a backflow control valve. According to the heat pump unit, high heat can be produced in the low-temperature environment when the water outlet temperature required by a user is high.

Description

Technical Field

[0001] The present invention relates to the field of electrical equipment technology, and in particular to a heat pump system, a control method of the heat pump system and a control device thereof. Background Art

[0002] In the related technology, according to the temperature limit of the compressor on the market, when the refrigerant return air temperature is lower than -40℃, the viscosity coefficient of the oil inside the compressor increases after mixing with the low-temperature refrigerant. It needs to be heated by the compressor heating belt for more than 120 minutes before the oil temperature rises before it can be started, resulting in a long start-up time and increased user costs. In addition, when the existing heat pump unit is turned on in the heating mode in an ultra-low temperature environment (for example, when the outdoor ambient temperature is lower than -30℃), the return air temperature on the evaporation side is as high as -30℃, and the refrigerant dryness of the return air cannot be guaranteed. If the return air refrigerant temperature is too low, it is easy to increase the compressor power and the exhaust temperature is too low.

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

[0004] The present invention provides a heat pump system, a control method for a heat pump system and a control device thereof, which are used to solve the defects in the prior art and achieve the following technical effects: when the outdoor ambient temperature is low and the user requires a higher outlet water temperature, at least one of the first heating branch, the second heating branch and the third heating branch can be selected to 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 embodiment of the present invention comprises:

[0006] An indoor heat exchanger, an electronic expansion valve, an outdoor heat exchanger, a four-way valve and a compressor connected by a refrigerant pipeline, wherein the four-way valve is connected to the air intake port of the compressor by an air intake branch;

[0007] Three heating branches connected in parallel are arranged between the indoor heat exchanger and the outdoor heat exchanger, including a first heating branch, a second heating branch and a third heating branch, and each of them is provided with a first one-way valve flowing toward one side of the outdoor heat exchanger, and the electronic expansion valve is respectively connected in series with the second heating branch and the third heating branch and connected in parallel with the first heating branch;

[0008] Wherein, a first control valve and a heat storage device are sequentially arranged on the first heating branch, and the heat storage device is thermally coupled with the air intake branch;

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

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

[0011] According to one embodiment of the present invention, the inlet and the 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-sensitive control valve and is respectively connected to the first temperature sensor and the second temperature sensor.

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

[0013] According to an 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 for flowing toward a side of the indoor heat exchanger is provided on the refrigeration branch.

[0014] According to a second aspect of the present invention, a control method for a heat pump unit based on the first aspect of the present invention comprises:

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

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

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

[0018] When the outdoor ambient temperature is in the first outdoor temperature zone, the first control valve, the enthalpy increase control valve, the second control valve and the return control valve are all controlled to be closed so that the heat storage device, the enthalpy increase heat exchanger and the return heat exchanger are all kept in a closed state;

[0019] Alternatively, when the outdoor ambient temperature is in the second outdoor temperature zone, the enthalpy increase control valve is controlled to open so that the enthalpy increase heat exchanger is in a working state, and the working states 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 one embodiment of the present invention, the step of controlling the working state and working parameters of the heat storage device and the recuperator according to the target outlet water temperature interval specifically includes:

[0022] When the target outlet water temperature is in the first outlet water temperature zone, controlling the first control valve, the second control valve and the reflux control valve to be closed so that the heat storage device and the reflux heat exchanger are both kept in a closed state;

[0023] Alternatively, when the target outlet water temperature is in the second outlet water temperature range, 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 control valve are controlled to be closed so that the return heat exchanger remains in a closed state;

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

[0025] According to one embodiment of the present invention, the step of generating control logic according to the outdoor ambient temperature and / or the target outlet water temperature, and controlling the working state and working parameters of the heat storage device, the enthalpy increasing heat exchanger and the recuperator according to the control logic specifically includes:

[0026] According to the outdoor ambient temperature being in the third outdoor temperature zone, controlling the first control valve, the enthalpy increase control valve, the second control valve and the return control valve to be opened so that the heat storage device, the enthalpy increase heat exchanger and the return heat exchanger are all in working state, wherein the third outdoor temperature zone is smaller than the second outdoor temperature zone;

[0027] After determining that the first control valve, the enthalpy increase control valve, the second control valve and the return control valve are all opened, obtaining the suction temperature of the compressor;

[0028] 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 according to the intake air temperature and the outdoor ambient temperature.

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

[0030] When the difference between the intake air temperature and the outdoor ambient temperature is less than or equal to a first set temperature difference, the opening of the first control valve is controlled to increase to a first heat storage opening, the opening of the reflux control valve is controlled to increase to a first reflux opening, and the opening of the electronic expansion valve is controlled to decrease to a first expansion opening;

[0031] Alternatively, 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 of the first control valve is controlled to be reduced to the second heat storage opening, the opening of the reflux control valve is controlled to be reduced to the second reflux opening, and the opening of the electronic expansion valve is controlled to be increased to the second expansion opening.

[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 according to the suction 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, obtaining an adjusted difference between the current suction air temperature and the outdoor ambient temperature;

[0034] According to the adjusted difference being less than or equal to the first set temperature difference or greater than or equal to the second set temperature difference, controlling the reflux control valve and the electronic expansion valve to restore to the initial reflux valve opening and the initial expansion valve opening respectively;

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

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

[0037] When the actual exhaust gas superheat is greater than the target exhaust gas superheat, controlling the opening of the electronic expansion valve to increase a first variable opening;

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

[0039] According to an embodiment of the present invention, the initial return valve opening, the initial expansion valve opening and the target exhaust gas superheat are all acquired at least according to the outdoor ambient temperature.

[0040] According to a third aspect of the present invention, a control device for a heat pump unit based on the first aspect of the present invention comprises:

[0041] an acquisition module, 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 a heating mode;

[0042] A control module is used to generate a control logic according to the outdoor ambient temperature and / or the target water outlet temperature, and control the working state and working parameters of the heat storage device, the enthalpy increase heat exchanger and the return heat exchanger according to the control logic.

[0043] The present invention provides a heat pump unit, which is provided with three heating branches, and the three heating branches are respectively composed of a heat storage device, an air-supplying and reheat-increasing device and a reflux device (reflux auxiliary circuit, reflux heat exchanger and reflux control valve), wherein the heat storage device can realize waste heat utilization, thereby improving the suction superheat of the compressor and ensuring the refrigerant dryness and refrigerant temperature on the suction side; the air-supplying and reheat-increasing device can, on the one hand, supercool the high-temperature refrigerant flowing out of the indoor heat exchanger, and on the other hand, increase the exhaust volume of the compressor, reduce the exhaust temperature and improve the heating capacity; the reflux device can reflux part of the high-temperature refrigerant flowing out of the indoor heat exchanger to the suction side of the compressor, so as to ensure the dryness and sensible heat of the refrigerant on the suction side of the compressor.

[0044] From the above, the three heating branches can all achieve the purpose of assisting the heat pump unit to produce high heat in a low-temperature environment. In this way, when the outdoor ambient temperature is low and the user requires a higher outlet water temperature, the purpose of producing high heat in a low-temperature environment can be achieved by selecting at least one of the first heating branch, the second heating branch and the third heating branch to be turned on and operated. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

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

[0047] Figure 2 It is a schematic flow chart of a control method of a heat pump unit provided by the present invention;

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

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

[0050] Reference numerals:

[0051] 1. Indoor heat exchanger; 2. Outdoor heat exchanger; 3. Compressor; 31. Enthalpy increase port; 32. Air intake port; 33. Air exhaust port; 34. Flash device; 35. First check 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. The third heating branch; 91. The reflux heat exchanger; 92. The second control valve; 93. The reflux auxiliary circuit; 94. The reflux control valve; 10. The cooling branch; 101. The second non-return valve; 110. The acquisition module; 120. The control module. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] The heat pump unit, the control method of the heat pump unit and the control device thereof provided by the present invention are introduced below with reference to the accompanying drawings. It should be pointed out that the control method and the control device provided by the present invention are implemented with the heat pump unit provided by the present invention as the structure.

[0057] like Figure 1 As shown, the heat pump unit according to the first embodiment 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 a refrigerant pipeline, wherein the refrigerant pipeline includes an intake branch (not shown in the figure), a first heating branch 7, a second heating branch 8 and a third heating branch 9 and other pipeline structures.

[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 through a refrigerant pipeline, wherein the four-way valve 5 and the air intake port 32 of the compressor 3 are connected through an air intake branch.

[0059] Three heating branches connected in parallel are provided between the indoor heat exchanger 1 and the outdoor heat exchanger 2, and the three heating branches are respectively a first heating branch 7, a second heating branch 8 and a third heating branch 9, and the three heating branches are all provided with a first one-way valve 35 flowing toward the side of the outdoor heat exchanger 2, wherein the electronic expansion valve 6 is respectively 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 merging, 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 with the air intake branch.

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

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

[0063] The heat pump unit according to the embodiment of the present invention is designed mainly to solve the problem that the heat pump unit cannot generate high heat under extreme working conditions in severe cold areas. The specific working principle is as follows: in the heating mode, if the outdoor environment of the area where the heat pump unit is located is a severe cold area, then according to the outdoor environment temperature and the target water outlet temperature set by the user, 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 open and work, so as to achieve the purpose of the heat pump unit generating high heat in severe cold areas.

[0064] Among them, 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 (that is, the condenser), and further use the heat recovered in the heat storage device 71 to heat the refrigerant on the suction side of the compressor 3 (that is, the suction branch), thereby increasing the suction superheat of the compressor 3, and then ensuring the refrigerant dryness and refrigerant temperature on the suction side, while reducing the power consumption of the compressor 3 and generating high heat.

[0065] The purpose of the second heating branch 8 is to use the air-increasing enthalpy-increasing device (including the enthalpy-increasing heat exchanger 81, the enthalpy-increasing auxiliary circuit 83 and the enthalpy-increasing control valve 82) to achieve the purpose of air-increasing enthalpy-increasing for the heat pump unit. On the one hand, the air-increasing enthalpy-increasing device can overcool 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-increasing; on the other hand, the air-increasing enthalpy-increasing device can increase the exhaust volume of the compressor 3, reduce the exhaust temperature, and improve the heating capacity, so that the heat pump air conditioner can provide sufficient heating capacity at low ambient temperature, that is, achieving the purpose of air-increasing.

[0066] The purpose of the third heating branch 9 is to use the return heat exchanger 91 and the return auxiliary path 93 to return part 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 is mixed with the gaseous high-temperature refrigerant flowing out of the return auxiliary path 93 and flows into the suction branch. At this time, part of the liquid refrigerant retained in the suction branch is basically completely evaporated into gaseous refrigerant due to the influence of the returning 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 assist the heat pump unit in producing high heat. Therefore, when the outdoor ambient temperature is low and the user requires a higher 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 selected to be turned on and operated to achieve the purpose of producing high heat in a low temperature environment.

[0068] Furthermore, as the outdoor ambient temperature continues to decrease, in order to achieve the purpose of high heat generation by the heat pump unit, the controller can control the first heating branch 7, the second heating branch 8 and the third heating branch 9 to open and work in sequence, that is, according to the different ranges of the outdoor ambient temperature and the ranges of the target water outlet temperature preset by the user, the heat pump unit can select different opening sequences and different opening quantities of the first heating branch 7, the second heating branch 8 and the third heating branch 9 to achieve the purpose of high heat generation in a low temperature environment.

[0069] It should be pointed out 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 open and work” means that the components on the heating branches are opened and working. For example, “selecting the first heating branch 7 to open and work” means controlling the first control valve 72 on the first heating branch 7 to open and controlling the heat storage device 71 to store heat; “selecting the second heating branch 8 to open and work” means controlling the enthalpy increase control valve 82 on the second heating branch 8 to open and controlling the enthalpy increase heat exchanger 81 to perform supercooling; “selecting the third heating branch 9 to open and work” means controlling the second control valve 92 and the reflux control valve 94 on the third heating branch 9 to open and controlling the reflux auxiliary road 93 to transport gaseous high-temperature refrigerant to the suction branch, and at the same time controlling the loop heat exchanger to perform supercooling.

[0070] In the related technology, according to the temperature limit of the compressor on the market, when the refrigerant return air temperature is lower than -40℃, the viscosity coefficient of the oil inside the compressor increases after mixing with the low-temperature refrigerant. It needs to be heated by the compressor heating belt for more than 120 minutes before the oil temperature rises before it can be started, resulting in a long start-up time and increased user costs. In addition, when the existing heat pump unit is turned on in the heating mode in an ultra-low temperature environment (for example, when the outdoor ambient temperature is lower than -30℃), the return air temperature on the evaporation side is as high as -30℃, and the refrigerant dryness of the return air cannot be guaranteed. If the return air refrigerant temperature is too low, it is easy to increase the power of compressor 3 and the exhaust temperature is too low.

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

[0072] In summary, in order to solve the technical defects existing in the above-mentioned related technologies, the present invention provides a heat pump unit, which is provided with three heating branches, and the three heating branches are respectively composed of a heat storage device 71, an air-supplying and reheat-increasing device and a reflux device (reflux auxiliary circuit 93, reflux heat exchanger 91 and reflux control valve 94), wherein the heat storage device 71 can realize waste heat utilization, thereby improving the suction superheat of the compressor 3, and ensuring the refrigerant dryness and refrigerant temperature on the suction side; the air-supplying and reheat-increasing device can, on the one hand, supercool the high-temperature refrigerant flowing out of the indoor heat exchanger 1, and on the other hand, increase the exhaust volume of the compressor 3, reduce the exhaust temperature, and improve the heating capacity; the reflux device can reflux part of the high-temperature refrigerant flowing out of the indoor heat exchanger 1 to the suction side of the compressor 3, so as to ensure the dryness and sensible heat of the refrigerant on the suction side of the compressor 3.

[0073] From the above, the three heating branches can all achieve the purpose of assisting the heat pump unit to produce high heat in a low-temperature environment. In this way, when the outdoor ambient temperature is low and the user requires a higher outlet water temperature, the purpose of producing high heat in a low-temperature environment can be achieved by 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.

[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-sensitive control valve and is respectively connected to the first temperature sensor 73 and the second temperature sensor 74.

[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 refrigerant temperature and the outlet refrigerant temperature can reflect the heat storage degree of the heat storage device 71. At the same time, it can be understood that since the heat storage degree 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 degree of the heat storage device 71, and the better the heating effect of the heat storage device 71 on the intake branch. Therefore, by controlling the opening of the temperature sensing 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 degree of the heat storage device 71, and then realizing 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 device 34 is further provided on the suction heating branch, and the flash device 34 is located downstream of the third heating branch 9. In this way, the flash device 34 is used in the unit to provide air supplement for the compressor 3. At this time, the refrigerant is in a high-temperature gas state, which can drive the compressor oil to heat up after mixing with the compressor oil, thereby reducing the power consumption under ultra-low temperature conditions and reducing the startup 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 for flowing toward the indoor heat exchanger 1 is provided on the refrigeration branch 10 .

[0078] It can be understood that when the heat pump unit operates in cooling mode, all the refrigerant flows through the cooling branch 10; when the heat pump unit operates 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 the present invention are described below with reference to the accompanying drawings. Among them, before the embodiment of the present invention is described in detail, the entire application scenario is first described. The control method, control device, electronic device and computer-readable storage medium of the heat pump unit of the embodiment of the present invention can be applied to the heat pump unit locally, and can also be applied to the cloud platform in the Internet field, or other types of cloud platforms in the Internet field, or can also be applied to third-party devices. Among them, the third-party device may include a variety of different types such as mobile phones, tablet computers, notebooks, car computers and other smart terminals.

[0080] The following description will only take the control method applicable to a heat pump unit as an example. It should be understood that the control method of the embodiment of the present invention can also be applied to a cloud platform and third-party equipment.

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

[0082] Step S1, when the heat pump unit is in heating mode, obtaining the outdoor ambient temperature and the target water outlet temperature of the heat pump unit;

[0083] Step S2, generating control logic according to the outdoor ambient temperature and / or the target water outlet temperature, and controlling the working states 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.

[0084] It can be understood that the above-mentioned control of the working status and working parameters of the heat storage device 71, the enthalpy increase 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 be turned on and operated according to the control logic, and adjusting their working parameters.

[0085] According to some embodiments of the present invention, the steps of generating control logic according to the outdoor ambient temperature and / or the target water outlet temperature, and controlling the working states 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 specifically include:

[0086] When the outdoor ambient temperature is in the first outdoor temperature zone, 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 in a closed state. The first outdoor temperature zone is greater than zero.

[0087] In this way, when the outdoor ambient temperature is in the first outdoor temperature zone, the outdoor ambient temperature is normal and does not belong to the low temperature severe cold situation, so the heat pump unit can be normally started and heated without assistance, that is, the controller controls the first control valve 72, the enthalpy increase control valve 82, the second control valve 92 and the return control valve 94 to be closed so that the heat storage device 71, the enthalpy increase heat exchanger 81 and the return heat exchanger 91 are all kept in a closed state. At this time, all the refrigerants flow normally through the second heating branch 8 and pass through the electronic expansion valve 6 and the outdoor heat exchanger 2 in turn to return to the compressor 3. For example, the first outdoor temperature zone can be 0°C to 20°C, and the present invention is not particularly limited here.

[0088] According to other embodiments of the present invention, the steps of generating control logic according to the outdoor ambient temperature and / or the target water outlet temperature, and controlling the working states 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 specifically include:

[0089] When the outdoor ambient temperature is in the second outdoor temperature zone, the enthalpy increase control valve 82 is controlled to open so that the enthalpy increase heat exchanger 81 is in working state, and the working state and working parameters of the heat storage device 71 and the reflux heat exchanger 91 are controlled according to the target water outlet temperature interval. The second outdoor temperature zone 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, and the purpose of producing high heat cannot be achieved by normal heating of the heat pump unit alone. Therefore, the controller controls the enthalpy increase control valve 82 to open so that the enthalpy increase heat exchanger 81 is in working state, thereby playing the role of replenishing air and increasing enthalpy, and maintaining the stable heat output of the heat pump unit. For example, the second outdoor temperature zone can be -25°C to 0°C, and the present invention is not particularly limited here.

[0091] Furthermore, the step of controlling the working state and working parameters of the heat storage device 71 and the reflux heat exchanger 91 according to the target outlet water temperature interval range specifically includes:

[0092] When the target outlet water temperature is in the first outlet water temperature zone, the first control valve 72, the second control valve 92 and the reflux control valve 94 are all controlled to be closed so that the heat storage device 71 and the reflux heat exchanger 91 are both kept in a closed state;

[0093] In this way, after the enthalpy increase control valve 82 is opened, if the target outlet water temperature preset by the user is not high, there is no need to open the heat storage device 71 and the reflux heat exchanger 91, and the user's needs can be met only by the opened air replenishment enthalpy increase device. For example, the first outlet water temperature zone can be 20°C to 35°C, and the present invention does not make any special restrictions here.

[0094] Furthermore, the step of controlling the working state and working parameters of the heat storage device 71 and the reflux heat exchanger 91 according to the target outlet water temperature interval range specifically includes:

[0095] When the target water outlet temperature is in the second water outlet temperature zone, the first control valve 72 is controlled to open so that the heat storage device 71 is in working state, and the second control valve 92 and the return control valve 94 are controlled to be closed so that the return heat exchanger 91 remains in a closed state; alternatively, the second control valve 92 and the return control valve 94 are controlled to be open so that the return heat exchanger 91 remains in an open state, and the first control valve 72 is controlled to be closed so that the heat storage device 71 is in a closed state.

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

[0097] In this way, if the target outlet water temperature preset by the user is high, the heating effect of the heat pump unit can be further improved by turning on 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 35°C to 60°C, and the present invention does not make any special restrictions here.

[0098] According to some further embodiments of the present invention, the steps of generating control logic according to the outdoor ambient temperature and / or the target outlet water temperature, and controlling the working states 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 specifically include:

[0099] According to 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 return control valve 94 are all controlled to be open so that the heat storage device 71, the enthalpy increase heat exchanger 81 and the return heat exchanger 91 are all in working state, wherein the third outdoor temperature zone is smaller than the second outdoor temperature zone;

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

[0101] The opening degree of at least one of the first control valve 72 , the enthalpy increase control valve 82 , the return control valve 94 and the electronic expansion valve 6 is controlled and adjusted according to the suction air temperature and the outdoor ambient temperature.

[0102] In this embodiment, when the outdoor ambient temperature is in the third outdoor temperature zone (for example, -40°C to -60°C), it means that the outdoor temperature is extremely low and cold. At this time, 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 reflux control valve 94 to be opened. At this time, the refrigerant flowing out of the indoor heat exchanger 1 passes through the heat storage device 71 of the first heating branch 7, the air replenishment enthalpy increase device of the second heating branch 8 and the reflux device of the third heating branch 9 to assist the unit in generating high heat.

[0103] It should be pointed out that in the above embodiment, the compressor 3 of the heat pump unit needs to run at a low frequency for a certain period of time during the initial startup stage, so as to achieve the pressure equalization process of the refrigerant in the system, and in the above low-frequency operation, the first control valve 72, the enthalpy increase control valve 82, the second control valve 92 and the reflux control valve 94 are also opened according to the preset initial opening. After the compressor 3 runs at a low frequency for a period of time, the compressor 3 continues to increase the frequency until the specified frequency is reached.

[0104] Furthermore, in the process of the compressor 3 first running at a low frequency and then increasing the frequency to a specified frequency, the openings of the first control valve 72, the enthalpy increase control valve 82, the second control valve 92 and the return control valve 94 are not fixed, but need to be adjusted according to changes in the suction temperature and the outdoor ambient temperature. In this way, on the one hand, adaptive changes can be made in time when the operating conditions change to ensure the high heat production performance of the unit in an extremely low temperature environment; on the other hand, the amount of refrigerant in the unit used to assist the operation of the compressor 3 and the amount of refrigerant used for heating and producing hot water can be coordinated and allocated, so as to achieve a balance between ensuring the stable operation of the compressor 3 and ensuring the water demand of the user, thereby further improving the user experience under the premise of ensuring the high heat production of the unit in an extremely low temperature environment.

[0105] In some specific embodiments of the present invention, the step of controlling and adjusting the opening 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 suction temperature and the outdoor ambient temperature specifically includes:

[0106] When the difference between the intake air temperature and the outdoor ambient temperature is less than or equal to the first set temperature difference, the opening of the first control valve 72 is controlled to increase to the first heat storage opening, the opening of the reflux control valve 94 is controlled to increase to the first reflux opening, and the opening of the electronic expansion valve 6 is controlled to decrease to the first expansion opening.

[0107] It can be understood that when the difference between the intake temperature and the outdoor ambient temperature is too small, it means that the intake temperature is low. At this time, it is necessary to control the opening of the first control valve 72 to increase to 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 intake branch; and it is necessary to control the opening of the return control valve 94 to increase to the first return opening, thereby increasing the amount of gaseous high-temperature refrigerant returning to the intake branch, enhancing the dryness of the refrigerant in the intake branch and eliminating its sensible heat; it is also necessary to control the opening of the electronic expansion valve 6 to decrease, so as to reduce the amount of refrigerant on one side of the outdoor heat exchanger 2, thereby reducing the operating burden of the compressor 3.

[0108] For example, the first set temperature difference may be 5° C., and the present invention does not impose any special limitation thereto.

[0109] In some other specific embodiments of the present invention, the step of controlling and adjusting the opening 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 suction temperature and the outdoor ambient temperature specifically includes:

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

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

[0112] For example, the second set temperature difference may be 20° C., and the present invention does not impose any particular limitation thereto.

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

[0114] According to some embodiments of the present invention, after the step of controlling and adjusting the opening 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 suction 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, obtaining an adjusted difference between the current suction air temperature and the outdoor ambient temperature;

[0116] According to the adjusted difference being 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 94 and the electronic expansion valve 6 are controlled to be restored to the initial reflux valve opening and the initial expansion valve opening respectively;

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

[0118] In this embodiment, after the adjustment of the opening 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 completed, 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 intake temperature and the outdoor ambient temperature continues to be obtained, and it is determined whether the adjusted difference meets the preset temperature condition. If so, no operation is performed, and all valves continue to be maintained at the current adjusted opening. If not, all valves in the unit are restored to the initial valve opening, and the electronic expansion valve 6 is further adjusted according to the superheat of the compressor 3 until the intake temperature meets the preset temperature condition.

[0119] Specifically, the step of controlling and adjusting the opening of the electronic expansion valve 6 according to the actual exhaust gas superheat and the target exhaust gas superheat includes:

[0120] When the actual exhaust gas superheat is greater than the target exhaust gas superheat, the opening of the electronic expansion valve 6 is controlled to increase the first variable opening;

[0121] When the actual exhaust gas superheat is lower than the target exhaust gas superheat, the opening degree of the electronic expansion valve 6 is controlled to decrease to a second variable opening degree.

[0122] It can be understood that when the actual exhaust superheat is high, the opening of the electronic expansion valve 6 is controlled to increase, so as to increase the proportion of the refrigerant used for heating and hot water production in the unit, and reduce the proportion of the refrigerant used for the auxiliary compressor 3 in the unit, thereby ensuring the user's heat use; when the actual exhaust superheat is low, the opening of the electronic expansion valve 6 is controlled to decrease, so as to increase the proportion of the refrigerant used for the auxiliary compressor 3 in the unit, and reduce the proportion of the 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 gas superheat are all obtained based on at least the outdoor ambient temperature.

[0124] A specific embodiment of the control method of 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 increase port 31, an air intake port 32 and an air exhaust port 33, an outdoor heat exchanger 2, a flash device 34, a four-way valve 5, a heat storage device 71, an enthalpy increase 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 increase control valve 82, an enthalpy increase 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 non-return valve 35, a second non-return 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 working modes of the heat pump unit are introduced as follows:

[0127] (1) In the first heating mode, the outdoor ambient temperature is 0°C to 20°C, and the target water outlet temperature is 20°C to 60°C. 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 in a closed state. The refrigerant in the unit all flows through the second heating branch 8 and is determined according to the outdoor ambient temperature and the target water outlet requirement set by the user. In this mode, there is no need to turn on enhanced heat exchange and ordinary heating can be performed.

[0128] (2) In the second heating mode, the outdoor ambient temperature is -25℃~0℃, and the target water outlet temperature is 20℃~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 both kept closed, and the refrigerant in the unit flows through the second heating branch 8 and the enthalpy increase control valve 82 is opened at the same time so that the enthalpy increase auxiliary path 83 and the enthalpy increase heat exchanger 81 work. As mentioned above, as the outdoor ambient temperature decreases, if the user sets a low water outlet requirement, the unit cannot produce high heat by relying on the normal mode alone, and the enthalpy increase device needs to be turned on to maintain a stable heat output.

[0129] (3) In the third heating mode, the outdoor ambient temperature is -25°C to 0°C, and the target outlet water temperature is 35°C to 60°C. At this time, the enthalpy increase control valve 82 and the first control valve 72 are respectively controlled to be open so that the enthalpy increase heat exchanger 81 and the heat storage device 71 are in working state, and the second control valve 92 and the return control valve 94 are both controlled to be closed so that the return heat exchanger 91 remains in a closed state. The refrigerant in the unit flows through the first heating branch 7 and the second heating branch 8 respectively. Taking the first temperature sensor 73 detecting the temperature T1 and the second temperature sensor 74 detecting the temperature T2 as an example, the temperature sensing control valve controls the refrigerant flow in the first heating branch 7 according to the formula (T1-T2=5°C), and then controls the heat exchange temperature between the heat storage device 71 and the suction branch. From the above, as the outdoor ambient temperature drops and the user's water output requirements increase, the unit must not only turn on the enthalpy increase mode, but also use the waste heat recovery device to control the temperature of the return air pipeline for heating, which helps to ensure the dryness and increase the temperature of the return air from compressor 3, reduce the power consumption of compressor 3, and generate high heat.

[0130] (4) In the fourth heating mode, the outdoor ambient temperature is: -40℃~-25℃, and the target water outlet temperature is: 20℃~60℃. During the initial startup of the unit, the compressor 3 first runs at a low frequency for 10 minutes and then continues to increase the frequency to the specified frequency. In the process of the above-mentioned compressor 3 changing from equalizing pressure low frequency operation to increasing the frequency to the specified frequency, the first control valve 72, the enthalpy increase control valve 82, the second control valve 92 and the return control valve 94 are all opened so that the heat storage device 71, the enthalpy increase heat exchanger 81 and the return heat exchanger 91 are all kept in working state, and the initial opening of the return control valve 94 is set to A, the initial opening 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. In addition, taking the case where the first temperature sensor 73 detects a temperature of T1 and the second temperature sensor 74 detects a temperature of 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°C), thereby controlling the heat exchange temperature between the heat storage device 71 and the intake branch.

[0131] The reflux auxiliary circuit 93 is a short circuit, and the opening of the reflux control valve 94 is 300, which is equivalent to 3 / 4 of its overall valve opening, so as to avoid the process of achieving rapid pressure equalization, and further avoid the compressor 3 from sucking liquid due to excessive valve opening. The purpose of setting the opening of the electronic expansion valve 6 to 100 is to slowly adjust the pressure on the evaporation side to avoid the pressure dropping too fast and the dryness of the generated gaseous refrigerant is not enough. In addition, the oil temperature in the middle of the compressor 3 is set to 20℃, which can avoid the increase of the viscosity coefficient of the oil due to too low oil temperature and avoid failure due to excessive power.

[0132] It can be understood that the refrigerant in the unit is simultaneously diverted to the first heating branch 7, the second heating branch 8 and the third heating branch 9, and in the process of the compressor 3 first running at a low frequency and then increasing the frequency to a specified frequency, the openings of the first control valve 72, the enthalpy increase control valve 82, the second control valve 92 and the return control valve 94 are not fixed, but need to be adjusted according to the changes in the suction temperature and the outdoor ambient temperature. Taking the suction temperature of the 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 reflux control valve 94 is increased by 5pls / min, and the electronic expansion valve 6 is reduced by 3pls / min. After the above-mentioned opening adjustment is completed, the unit maintains the adjusted opening and continues to operate for 20 minutes before determining the difference between the suction temperature Ts and the outdoor ambient temperature Tao again.

[0134] When the suction temperature Ts and the outdoor ambient temperature Tao do not satisfy 5°C<(Ts-Tao)<20°C, the reflux control valve 94 and the electronic expansion valve 6 are controlled to return to their respective initial valve openings, wherein the calculation formula of the initial valve opening Y1 is:

[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 respective initial valve openings, the actual exhaust superheat of the current compressor 3 is further compared with the target exhaust superheat, 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 5pls / min; when the actual exhaust superheat is equal to the target exhaust superheat, the electronic expansion valve 6 maintains the 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 20pls / min. Among them, the empirical calculation formula for the above target exhaust superheat is: target exhaust superheat = {1 / 2*(compressor 3 maximum operating frequency-Tao)+0.1*(compressor 3 current frequency)+Tao / (Tao+5)*(Two-55)}*0.5, wherein Two is the target outlet water temperature.

[0137] (4.2) 5℃<Ts-Tao<20℃: All valve openings maintain the current openings. When the difference between the suction temperature and the outdoor ambient temperature is about 5℃, the suction refrigerant maintains a relatively high dryness. As the temperature difference increases, the suction refrigerant also has a certain degree of superheat. It can be understood 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 reflux 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-mentioned opening adjustments are completed, the unit maintains the adjusted opening and continues to operate for 10 minutes before determining the difference between the suction temperature Ts and the outdoor ambient temperature Tao again.

[0139] When the suction temperature Ts and the outdoor ambient temperature Tao do not satisfy 5°C<(Ts-Tao)<20°C, the reflux control valve 94 and the electronic expansion valve 6 are controlled to return to their respective initial valve openings, wherein the calculation formula of the initial valve opening Y2 is:

[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 respective initial valve openings, the actual exhaust superheat of the current compressor 3 is further compared with the target exhaust superheat, 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 5pls / min; when the actual exhaust superheat is equal to the target exhaust superheat, the electronic expansion valve 6 maintains the 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 5pls / min. Among them, the empirical calculation formula for the above target exhaust superheat is: target exhaust superheat = {1 / 2*(compressor 3 maximum operating frequency-Tao)+0.1*(compressor 3 current frequency)+Tao / (Tao+5)*(Two-55)}*0.55, wherein Two is the target outlet water temperature.

[0142] In summary, the heat pump system and control method thereof according to the embodiment of the present invention, through the heat pump system principle of parallel plate heat exchangers combined with the optimized control logic of three-chamber flow diversion, helps to solve the problem that the heat pump cannot produce high heat at ultra-low outdoor ambient temperature in severe cold areas, and its specific advantages are as follows:

[0143] 1. The oil in compressor 3 is affected by the low ambient temperature at the ultra-low temperature outdoor environment, and its own viscosity coefficient increases. It relies on the electric heating belt of the compressor for preheating, which leads to an increase in the economic cost of users. At the same time, the oil heating process is prolonged and the power alarm is easily triggered. The present invention uses a simple flow path to quickly equalize the pressure, establish a pressure ratio, and use the flash device 34 to provide air replenishment for compressor 3. At this time, the refrigerant is in a high-temperature gas state. After mixing with the compressor oil, it can drive the compressor oil to heat up, reducing the ultra-low temperature working condition. The unit can only be started after being heated by the compressor heating belt, reducing electricity consumption, and reducing the startup time of the unit. The high-temperature gaseous refrigerant of the return air is used to drive the compressor 3 oil temperature to heat up quickly, reducing the startup time of the unit, and providing safe operation guarantee for the ultra-low temperature outdoor environment temperature of compressor 3.

[0144] 2. Under the ultra-low temperature outdoor operating environment, if there is too much two-phase refrigerant in the outdoor heat exchanger 2, the return air may contain gaseous refrigerant with low dryness and low temperature, which is not conducive to high heat generation of the unit. The present invention applies the parallel plate heat exchange method and the waste heat recovery technology to the air source heat pump system, which mainly increases the suction superheat of the compressor 3 and ensures the dryness of the refrigerant on the suction side. In this way, the present invention combines the parallel plate heat exchange system with the waste heat recovery system. While reasonably allocating each flow rate, it can make full use of the heat storage device 71 on the first heating branch 7 to recycle the waste heat of the refrigerant in the indoor heat exchanger 1, and use the air replenishment enthalpy increase device on the second heating branch 8 to ensure that the return air refrigerant flow of the compressor 3 reaches the air replenishment state to prevent large overheating from harming the unit, and use the reflux device on the third heating branch 9 to ensure the dryness and sensible heat of the return air refrigerant on the evaporation side.

[0145] The control device of the heat pump unit provided by the present invention is described below. The control device of the heat pump unit described below and the control method of the heat pump unit described above can be referred to each other.

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

[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 the heating mode;

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

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

[0150] In addition, the logic instructions in the above-mentioned memory 830 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

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

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

[0153] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0154] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment 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, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A heat pump unit, characterized in that: include: An indoor heat exchanger, an electronic expansion valve, an outdoor heat exchanger, a four-way valve and a compressor connected by a refrigerant pipeline, wherein the four-way valve is connected to the air intake port of the compressor by an air intake branch; Three heating branches connected in parallel are arranged between the indoor heat exchanger and the outdoor heat exchanger, including a first heating branch, a second heating branch and a third heating branch, and each of them is provided with a first one-way valve flowing toward one side of the outdoor heat exchanger, and the electronic expansion valve is respectively connected in series with the second heating branch and the third heating branch and connected in parallel with the first heating branch; Wherein, a first control valve and a heat storage device are sequentially arranged on the first heating branch, and the heat storage device is thermally coupled with the air intake branch; The second heating branch is provided with a thermally coupled enthalpy-increasing heat exchanger and an enthalpy-increasing auxiliary path, the two ends of the enthalpy-increasing auxiliary path are respectively connected to the second heating branch and the enthalpy-increasing port of the compressor, and the enthalpy-increasing auxiliary path is provided with an enthalpy-increasing control valve; The third heating branch is provided with a thermally coupled reflux auxiliary circuit and a reflux heat exchanger, the two ends of the reflux auxiliary circuit are respectively connected to the third heating branch and the suction branch, and the third heating branch is also provided with a second control valve, and the reflux auxiliary circuit is provided with a reflux control valve.

2. The heat pump unit according to claim 1, characterized in that: The inlet and the 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-sensitive control valve and is respectively connected to the first temperature sensor and the second temperature sensor.

3. The heat pump unit according to claim 1, characterized in that: The air suction heating branch is also provided with a flash device, and the flash device is located downstream of the third heating branch.

4. The heat pump unit according to any one of claims 1 to 3, characterized in that: A refrigeration branch is also provided between the indoor heat exchanger and the electronic expansion valve. A second one-way valve for flowing toward one side of the indoor heat exchanger is provided on the refrigeration branch.

5. A control method for a heat pump unit according to any one of claims 1 to 4, characterized in that: include: When the heat pump unit is in heating mode, obtaining the outdoor ambient temperature and the target water outlet temperature of the heat pump unit; A control logic is generated according to the outdoor ambient temperature and / or the target water outlet temperature, and the operating states and operating parameters of the heat storage device, the enthalpy-increasing heat exchanger and the return heat exchanger are controlled according to the control logic.

6. The control method of the heat pump unit according to claim 5, characterized in that: The step of generating control logic according to the outdoor ambient temperature and / or the target outlet water temperature, and controlling the working states and working parameters of the heat storage device, the enthalpy-increasing heat exchanger and the recuperator according to the control logic specifically includes: When the outdoor ambient temperature is in the first outdoor temperature zone, the first control valve, the enthalpy increase control valve, the second control valve and the return control valve are all controlled to be closed so that the heat storage device, the enthalpy increase heat exchanger and the return heat exchanger are all kept in a closed state; Alternatively, when the outdoor ambient temperature is in the second outdoor temperature zone, the enthalpy increase control valve is controlled to open so that the enthalpy increase heat exchanger is in a working state, and the working states 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; Wherein, the first outdoor temperature zone is greater than zero, and the second outdoor temperature zone is less than zero.

7. The control method of the heat pump unit according to claim 6, characterized in that: The step of controlling the working state and working parameters of the heat storage device and the recuperator according to the target water outlet temperature interval specifically includes: When the target outlet water temperature is in the first outlet water temperature zone, controlling the first control valve, the second control valve and the reflux control valve to be closed so that the heat storage device and the reflux heat exchanger are both kept in a closed state; Alternatively, when the target outlet water temperature is in the second outlet water temperature range, 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 control valve are controlled to be closed so that the return heat exchanger remains in a closed state; Wherein, the first water outlet temperature zone is smaller than the second water outlet temperature zone.

8. The control method of the heat pump unit according to claim 6 or 7, characterized in that: The step of generating control logic according to the outdoor ambient temperature and / or the target outlet water temperature, and controlling the working states and working parameters of the heat storage device, the enthalpy-increasing heat exchanger and the recuperator according to the control logic specifically includes: According to the outdoor ambient temperature being in the third outdoor temperature zone, controlling the first control valve, the enthalpy increase control valve, the second control valve and the return control valve to be opened so that the heat storage device, the enthalpy increase heat exchanger and the return heat exchanger are all in 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 increase control valve, the second control valve and the return control valve are all opened, obtaining the suction temperature of the compressor; 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 according to the intake air temperature and the outdoor ambient temperature.

9. The control method of the heat pump unit according to claim 8, characterized in that: The step of controlling and adjusting the opening of at least one of the first control valve, the enthalpy increase control valve, the reflux control valve and the electronic expansion valve according to the intake air temperature and the outdoor ambient temperature specifically includes: When the difference between the intake air temperature and the outdoor ambient temperature is less than or equal to a first set temperature difference, the opening of the first control valve is controlled to increase to a first heat storage opening, the opening of the reflux control valve is controlled to increase to a first reflux opening, and the opening of the electronic expansion valve is controlled to decrease to a first expansion opening; Alternatively, 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 of the first control valve is controlled to be reduced to the second heat storage opening, the opening of the reflux control valve is controlled to be reduced to the second reflux opening, and the opening of the electronic expansion valve is controlled to be increased to the second expansion opening.

10. The control method of the heat pump unit according to claim 8, characterized in that: 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 according to the suction temperature and the outdoor ambient temperature, the method further includes: After the heat pump unit has been running for at least a preset time, obtaining an adjusted difference between the current suction air temperature and the outdoor ambient temperature; According to the adjusted difference being less than or equal to the first set temperature difference or greater than or equal to the second set temperature difference, controlling the reflux control valve and the electronic expansion valve to restore to the initial reflux valve opening and the initial expansion valve opening respectively; The actual exhaust superheat and the target exhaust superheat of the current compressor are obtained, and the opening of the electronic expansion valve is controlled and adjusted according to the actual exhaust superheat and the target exhaust superheat.

11. The control method of the heat pump unit according to claim 10, characterized in that: The step of controlling and adjusting the opening of the electronic expansion valve according to the actual exhaust gas superheat and the target exhaust gas superheat specifically includes: When the actual exhaust gas superheat is greater than the target exhaust gas superheat, controlling the opening of the electronic expansion valve to increase a first variable opening; When the actual exhaust gas superheat is less than the target exhaust gas superheat, the opening degree of the electronic expansion valve is controlled to decrease by a second variable opening degree.

12. The control method of the heat pump unit according to claim 11, characterized in that: The initial return valve opening, the initial expansion valve opening, and the target exhaust gas superheat are all acquired at least according to the outdoor ambient temperature.

13. A control device for a heat pump unit according to any one of claims 1 to 4, characterized in that: include: an acquisition module, 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 a heating mode; A control module is used to generate a control logic according to the outdoor ambient temperature and / or the target water outlet temperature, and control the working state and working parameters of the heat storage device, the enthalpy increase heat exchanger and the return heat exchanger according to the control logic.

Images