Air source heat pump system and operation control method of air source heat pump system

Abstract

The invention relates to the technical field of heat pump systems, in particular to an air source heat pump system and an operation control method of the air source heat pump system, and aims to solve the problems that when the climate of an existing air source heat pump in a severe cold area is lower than-30 DEG C, the capacity and energy efficiency of a unit are poor, the unit mainly depends on an electric heating system and an energy storage water tank to supply heat, and the working efficiency is low. And the use cost of the user is increased. In order to achieve the purpose, the air source heat pump system comprises a first-stage air source heat pump system, a second-stage air source heat pump system and a water storage tank, and the first-stage air source heat pump system and the second-stage air source heat pump system are arranged to be capable of heating circulating water in the water storage tank in an independent heating mode or a combined heating mode of the first-stage air source heat pump system and the second-stage air source heat pump system. According to the air source heat pump system, the first-stage air source heat pump system and the second-stage air source heat pump system can be started to conduct a linkage heating mode in a severe ultralow-temperature environment, the energy efficiency can be improved, and the purpose of providing stable heat for a user is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pump systems, and specifically provides an air source heat pump system and an operation control method of the air source heat pump system. Background Art

[0002] As people's living standards continue to improve, providing domestic hot water throughout the year has become an important part of people's comfortable lives. Traditional gas and electric water heaters have safety hazards such as emission of harmful combustion products and easy leakage, and consume high-quality energy such as gas and electricity, which is inconsistent with the sustainable development of new energy systems based on renewable energy. When solar water heaters are short of sunshine due to climate and seasonal changes, they have the disadvantages of poor heating capacity balance and low annual utilization rate of the device.

[0003] In recent years, air source heat pumps have widely replaced coal-fired heating as a means of heating in rural areas of extremely cold regions. However, the existing air source heat pumps in extremely cold regions have poor unit capacity and energy efficiency performance when the climate is below -30°C and cannot produce high capacity. The units mainly rely on electric heating systems and energy storage tanks for heating, which increases user costs. When the units are operating below -37°C, the basic capacity is at 50% of the nominal operating capacity.

[0004] Therefore, the present invention needs to provide a new air source heat pump system and an operation control method of the air source heat pump system to solve the above technical problems. Summary of the invention

[0005] The present invention aims to solve the above technical problem, that is, to solve the problem that the existing air source heat pumps have widely replaced coal-fired heating in rural heating methods in severe cold regions, but the existing air source heat pumps in severe cold regions have poor unit capacity and energy efficiency performance when the climate is below -30°C (harsh ultra-low temperature environment), and the units mainly rely on electric heating systems and energy storage water tanks for heating, which leads to increased user costs.

[0006] To this end, in a first aspect, the present invention provides an air source heat pump system, comprising a primary air source heat pump system, a secondary air source heat pump system and a water tank, wherein the primary air source heat pump system and the secondary air source heat pump system are configured to heat circulating water in the water tank in a separate heating mode or a linked heating mode of the two, and in the linked heating mode, the circulating water in the water tank heated by the primary air source heat pump system is heated again by the secondary air source heat pump system and then delivered to a user.

[0007] When the above technical solution is adopted, under conditions with low capacity requirements, heating is only performed through the primary air source heat pump system to avoid overheating waste; when the operating temperature is above the set temperature below zero, only the secondary air source heat pump system can be turned on for heating; in harsh ultra-low temperature environments, the primary air source heat pump system and the secondary air source heat pump system are turned on for a linkage heating mode. After the primary air source heat pump system heats the circulating water in the water storage tank, the heated circulating water passes through the secondary air source heat pump system, providing water inlet temperature rising conditions for the secondary air source heat pump system to produce high-temperature water, thereby achieving the purpose of providing stable heat for users.

[0008] In a specific embodiment of the above-mentioned air source heat pump system, the air source heat pump system also includes a first refrigerant pipeline and a second refrigerant pipeline. In the heating mode, part of the refrigerant discharged from the exhaust port of the primary air source heat pump system can be transported to the intake port of the secondary air source heat pump system through the first refrigerant pipeline, and part of the refrigerant in the secondary air source heat pump system that has undergone heat exchange with the circulating water in the water storage tank is transported to the primary air source heat pump system through the second refrigerant pipeline. A first valve is installed on the first refrigerant pipeline, and a second valve is installed on the second refrigerant pipeline.

[0009] When the above technical solution is adopted, in the heating mode, part of the high-temperature gaseous refrigerant discharged from the exhaust port of the primary air source heat pump system enters the intake port of the secondary air source heat pump system through the first refrigerant pipeline, thereby increasing the refrigerant temperature at the intake port during the compression process of the secondary air source heat pump system, providing medium and high temperature gaseous refrigerant for the rapid startup of the secondary air source heat pump system, quickly achieving pressure balance of the unit, reducing the start-up time of the secondary compression, and having the function of supplementing refrigerant for the secondary air source heat pump system.

[0010] In a specific embodiment of the above-mentioned air source heat pump system, the primary air source heat pump system includes a primary compressor, a venturi ejector and a first heat exchange component, the exhaust port of the primary compressor is connected to the air inlet of the venturi ejector, the air outlet of the venturi ejector is connected to the air intake port of the primary compressor through the first heat exchange component, and the venturi ejector diverts the refrigerant at the outlet end of the secondary air source heat pump system serving as an evaporator in the heating mode into the venturi ejector through the second refrigerant pipeline to reduce the negative pressure of the evaporator.

[0011] When the above technical solution is adopted, a venturi flowmeter is used to spray high-temperature gaseous refrigerant, and a high-speed flow rate of gaseous refrigerant is achieved after passing through a variable-diameter nozzle. The reduced pressure after the nozzle is conducive to the injection of low-temperature gaseous refrigerant at the outlet end of the evaporator in the two-stage air source heat pump system in the heating mode, creating a lower negative pressure inside the evaporator in the two-stage air source heat pump system, so that the two-phase refrigerant in the evaporator during the compression process of the two-stage air source heat pump system absorbs more heat from the ambient temperature, and more low-pressure liquid refrigerant flashes into low-pressure gaseous refrigerant, ensuring the dryness of the gaseous refrigerant, which is beneficial to the high capacity of the unit.

[0012] In a specific embodiment of the above-mentioned air source heat pump system, the first heat exchange component includes a heat exchange coil, a first heat exchanger and a first four-way valve, the heat exchange coil is arranged on the water storage tank, the air outlet of the venturi ejector is connected to the first end of the first heat exchanger through the first four-way valve and the heat exchange coil, the second end of the first heat exchanger is connected to the suction port of the first-stage compressor through the first four-way valve, and a third valve is arranged between the first heat exchanger and the first four-way valve.

[0013] In a specific embodiment of the above-mentioned air source heat pump system, the two-stage air source heat pump system includes a two-stage compressor, a second heat exchange component and a waste heat recovery component. The second heat exchange component is arranged between the exhaust port and the air intake port of the two-stage compressor. The second heat exchange component can exchange heat with the circulating water in the water storage tank. The waste heat recovery component is used to recover the waste heat of the refrigerant after the second heat exchange component exchanges heat with the circulating water in the water storage tank in the heating mode and to perform heat exchange with the refrigerant entering the air intake port of the two-stage compressor.

[0014] When the above technical solution is adopted, the waste heat recovery component is used to recover the waste heat of the refrigerant after heat exchange with the circulating water in the water storage tank, and the waste heat is used to exchange heat with the refrigerant entering the air intake port, thereby increasing the refrigerant temperature at the air intake port and providing basic conditions for creating high capacity for the secondary compressor.

[0015] In a specific embodiment of the above-mentioned air source heat pump system, the second heat exchange component includes a second heat exchanger, a third heat exchanger and a second four-way valve, the exhaust port of the secondary compressor is connected to the first end of the third heat exchanger through the second four-way valve and the second heat exchanger, the second end of the third heat exchanger is connected to the intake port of the secondary compressor through the second four-way valve, the other end of the second refrigerant pipeline is connected to the second end of the third heat exchanger, and the third heat exchanger is an evaporator in the heating mode.

[0016] In a specific embodiment of the above-mentioned air source heat pump system, the waste heat recovery component includes a temperature-sensitive control valve, a fourth heat exchanger and a first pipeline. The temperature-sensitive control valve, the fourth heat exchanger and the sixth valve are installed in sequence on the first pipeline according to the flow direction of the refrigerant. One end of the first pipeline is connected to the refrigerant outlet end on the second heat exchanger, and the other end of the first pipeline is connected to the first end of the third heat exchanger. The refrigerant after passing through the second four-way valve exchanges heat with the fourth heat exchanger and then enters the suction port of the secondary compressor.

[0017] When the above technical solution is adopted, the waste heat of the refrigerant after passing through the second heat exchanger is recovered and utilized by utilizing the cooperation of the temperature-sensitive control valve and the fourth heat exchanger, thereby improving energy utilization and increasing the refrigerant temperature at the suction port of the secondary compressor, which helps the secondary compressor to produce high capacity.

[0018] In a specific embodiment of the above-mentioned air source heat pump system, the air source heat pump system also includes a second pipeline and a third pipeline, the second end of the first heat exchanger is connected to the exhaust port of the secondary compressor through the second pipeline, the first end of the first heat exchanger is connected to the first end of the third heat exchanger through the third pipeline, a fourth valve is installed on the second pipeline, and a fifth valve is installed on the third pipeline, the first heat exchanger, the second pipeline, the third pipeline, the secondary compressor and the second heat exchange assembly are combined to form a refrigeration system for cooling the circulating water in the water storage tank.

[0019] When the above technical solution is adopted, when the two-stage air source heat pump system is cooling, part of the refrigerant enters the first heat exchanger, so that the first heat exchanger and the third heat exchanger exchange heat together, which increases the heat exchange area and ensures the cooling capacity.

[0020] In a second aspect, the present invention further provides an operation control method of an air source heat pump system, wherein the air source heat pump system is the air source heat pump system described in any one of the above technical solutions, and the operation control method comprises:

[0021] In heating mode, obtain the ambient temperature and the water outlet temperature of the water storage tank;

[0022] If the ambient temperature is greater than or equal to a first preset ambient temperature value, and the outlet water temperature is less than or equal to a first preset value, the primary air source heat pump system is controlled to execute a heating mode, and the secondary air source heat pump system is in a standby state; and / or

[0023] If the outlet water temperature is greater than a first preset value and less than or equal to a second preset value, and the ambient temperature is greater than or equal to the first preset ambient temperature value or the ambient temperature is greater than or equal to the second preset ambient temperature value and less than the first preset ambient temperature value, the secondary air source heat pump system is controlled to execute a heating mode, and the primary air source heat pump system is in a standby state; and / or

[0024] If the water outlet temperature is greater than the first preset value and less than or equal to the second preset value, and the ambient temperature is greater than or equal to the third preset ambient temperature value and less than the second preset ambient temperature value, the primary air source heat pump system and the secondary air source heat pump system are controlled to execute the linkage heating mode.

[0025] When the above technical solution is adopted, in the heating mode, the present invention can automatically control the working states of the primary air source heat pump system and the secondary air source heat pump system according to different working conditions, with a high degree of intelligence, so as to provide stable heat for users.

[0026] In a specific implementation of the above-mentioned operation control method of the air source heat pump system, the air source heat pump system pre-stores a plurality of preset refrigerant temperature difference values ​​corresponding to different ambient temperatures, and the operation control method further includes:

[0027] According to the size of the ambient temperature, the opening of the temperature-sensing control valve is controlled to adjust the refrigerant temperature difference between the inlet and outlet ends of the fourth heat exchanger.

[0028] When the above technical solution is adopted, the suction superheat is adjusted by controlling the opening of the temperature-sensitive control valve to ensure the suction superheat. Under low-temperature heating conditions, the compressor can be effectively prevented from returning liquid, thereby ensuring the exhaust superheat and providing the basic conditions for high capacity of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings, in which:

[0030] Figure 1 It is an overall principle diagram of the air source heat pump system provided by the present invention;

[0031] Figure 2 It is a schematic diagram of the linkage heating of the primary air source heat pump system and the secondary air source heat pump system;

[0032] Figure 3 It is the schematic diagram of the air source heat pump system corresponding to the cooling mode.

[0033] List of reference numerals:

[0034] 1. First-stage compressor; 2. Venturi ejector; 3. First four-way valve; 4. First heat exchanger; 5. Third valve; 6. Fourth valve; 7. Water storage tank; 8. Circulating water outlet; 9. Circulating water inlet; 10. Second refrigerant pipeline; 11. Second valve; 12. Third pipeline; 13. First refrigerant pipeline; 14. First valve; 15. Second heat exchanger; 16. Second-stage compressor; 17. Second four-way valve; 18. Third heat exchanger; 19. First pipeline; 20. Temperature-sensing control valve; 21. Fourth heat exchanger; 22. Sixth valve; 23. Fifth valve; 24. Second pipeline; 25. Water supply pipeline; 26. Make-up water pipeline. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not used to limit the scope of protection of the present invention. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0036] It should be noted that in the description of the present invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the relevant devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, ordinal numbers such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0037] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] Existing air source heat pumps have widely replaced coal-fired heating as a means of heating in rural areas of extremely cold regions. However, the existing air source heat pumps in extremely cold regions have poor unit capacity and energy efficiency performance when the climate is below -30°C. The units mainly rely on electric heating systems and energy storage tanks for heating, which increases user costs.

[0039] To solve the above technical problems, refer to Figure 1-3The present invention provides an air source heat pump system, which includes a primary air source heat pump system, a secondary air source heat pump system and a water storage tank 7. The primary air source heat pump system and the secondary air source heat pump system are configured to heat the circulating water in the water storage tank 7 in a separate heating mode or a linkage heating mode. In the linkage heating mode, the circulating water in the water storage tank 7 heated by the primary air source heat pump system is heated again by the secondary air source heat pump system and then delivered to the user. The water storage tank 7 is an energy storage water tank.

[0040] In the above embodiment, after the primary air source heat pump system heats the circulating water in the water storage tank 7, the heated circulating water is passed through the secondary air source heat pump system, which provides water inlet temperature rising conditions for the secondary air source heat pump system to produce high-temperature hot water, thereby helping the secondary air source heat pump system to produce high-temperature hot water.

[0041] In one embodiment, the air source heat pump system also includes a first refrigerant pipeline 13 and a second refrigerant pipeline 10. In the heating mode, part of the refrigerant discharged from the exhaust port of the primary air source heat pump system can be transported to the intake port of the secondary air source heat pump system through the first refrigerant pipeline 13, and part of the refrigerant in the secondary air source heat pump system that has undergone heat exchange with the circulating water in the water storage tank 7 is transported to the primary air source heat pump system through the second refrigerant pipeline 10. A first valve 14 is installed on the first refrigerant pipeline 13, and a second valve 11 is installed on the second refrigerant pipeline 10.

[0042] In the above embodiment, in the heating mode, part of the high-temperature gaseous refrigerant discharged from the exhaust port of the primary air source heat pump system enters the air intake port of the secondary air source heat pump system through the first refrigerant pipeline 13, thereby increasing the refrigerant temperature at the air intake port during the compression process of the secondary air source heat pump system, providing medium and high temperature gaseous refrigerant for the rapid startup of the secondary air source heat pump system, quickly achieving pressure balance of the unit, reducing the startup time of the secondary compression, and having the function of supplementing refrigerant for the secondary air source heat pump system.

[0043] In one embodiment, a primary air source heat pump system includes a primary compressor 1, a venturi ejector 2 and a first heat exchange component. The exhaust port of the primary compressor 1 is connected to the air inlet of the venturi ejector 2, and the air outlet of the venturi ejector 2 is connected to the air intake of the primary compressor 1 through the first heat exchange component. The venturi ejector 2 draws part of the refrigerant at the outlet end of the secondary air source heat pump system serving as an evaporator in the heating mode into the venturi ejector 2 through the second refrigerant pipeline 10 to reduce the negative pressure of the evaporator.

[0044] Specifically, the exhaust port of the primary compressor 1 is connected to a three-way valve, and the first refrigerant pipeline 13 and the venturi ejector 2 are respectively connected through the three-way valve. A confluence port is provided on the venturi ejector 2, and one end of the second refrigerant pipeline 10 is connected to the confluence port. The high-temperature gaseous refrigerant is ejected by a venturi flowmeter, and a high-speed flow rate of the gaseous refrigerant is achieved after passing through a variable-diameter nozzle. The pressure after the nozzle is reduced, and the pressure inside the evaporator of the secondary air source heat pump system in the heating mode is relatively high. Therefore, the low-temperature gaseous refrigerant at the outlet end of the evaporator in the secondary air source heat pump system in the heating mode is injected into the venturi ejector 2, thereby creating a lower negative pressure inside the evaporator in the secondary air source heat pump system, so that the two-phase refrigerant in the evaporator during the compression process of the secondary air source heat pump system absorbs more heat in the ambient temperature, and more low-pressure liquid refrigerant flashes into low-pressure gaseous refrigerant, ensuring the dryness of the gaseous refrigerant, which is conducive to the high capacity of the secondary air source heat pump system.

[0045] In one embodiment, the first heat exchange assembly includes a heat exchange coil, a first heat exchanger 4 and a first four-way valve 3, the heat exchange coil is arranged on the water storage tank 7, the air outlet of the venturi ejector 2 is connected to the first end of the first heat exchanger 4 through the first four-way valve 3 and the heat exchange coil, the second end of the first heat exchanger 4 is connected to the air intake of the first compressor 1 through the first four-way valve 3, and a third valve 5 is arranged between the first heat exchanger 4 and the first four-way valve 3. The first heat exchanger 4 can be a plate heat exchanger.

[0046] Specifically, the Venturi ejector 2 and the first four-way valve 3, the first four-way valve 3 and the heat exchange coil, and the heat exchange coil and the first heat exchanger 4 are all connected by pipelines, an electronic expansion valve is installed on the pipeline between the heat exchange coil and the first heat exchanger 4, and the third valve 5 is installed on the pipeline between the first heat exchanger 4 and the first four-way valve 3.

[0047] In one embodiment, the secondary air source heat pump system includes a secondary compressor 16, a second heat exchange component and a waste heat recovery component. The second heat exchange component is arranged between the exhaust port and the air intake port of the secondary compressor 16. The second heat exchange component can exchange heat with the circulating water in the water storage tank 7. The waste heat recovery component is used to recover the waste heat of the refrigerant after the second heat exchange component exchanges heat with the circulating water in the water storage tank 7 in the heating mode and to perform heat exchange with the refrigerant entering the air intake port of the secondary compressor 16. The other end of the first refrigerant pipeline 13 is connected to the air intake port of the secondary compressor 16.

[0048] In one embodiment, the second heat exchange assembly includes a second heat exchanger 15, a third heat exchanger 18 and a second four-way valve 17. The exhaust port of the secondary compressor 16 is connected to the first end of the third heat exchanger 18 through the second four-way valve 17 and the second heat exchanger 15. The second end of the third heat exchanger 18 is connected to the air intake port of the secondary compressor 16 through the second four-way valve 17. The other end of the second refrigerant pipeline 10 is connected to the second end of the third heat exchanger 18. In the heating mode, the third heat exchanger 18 is an evaporator. The second heat exchanger 15 can be a shell and tube heat exchanger, and the third heat exchanger 18 can be a plate heat exchanger. The circulating water in the water storage tank 7 enters the second heat exchanger 15 for heat exchange and is then transported to the circulating water outlet 8 of the water storage tank 7. The user obtains hot water or cold water from the circulating water outlet 8.

[0049] Specifically, the exhaust port of the secondary compressor 16 and the second four-way valve 17, the second four-way valve 17 and the second heat exchanger 15, the second heat exchanger 15 and the third heat exchanger 18, the third heat exchanger 18 and the second four-way valve 17, and the second four-way valve 17 and the air intake port of the secondary compressor 16 are all connected by pipelines, and an electromagnetic expansion valve is installed on the pipeline between the second heat exchanger 15 and the third heat exchanger 18. The pipeline between the second four-way valve 17 and the secondary compressor 16 passes through the fourth heat exchanger 21 to perform heat exchange. The water tank 7 is provided with a water delivery pipeline 25, which is connected to the water inlet of the second heat exchanger 15, and is also connected to the water supply pipeline 26, which is used to supply water to the water tank 7. The circulating water in the water tank 7 can enter the second heat exchanger 15 through the water delivery pipeline 25 for heat exchange. The water tank 7 is provided with a circulating water outlet 8 and a circulating water inlet 9. The water from the circulating water outlet 8 is directly delivered to the user, and the circulating water in the water tank 7 flows back from the circulating water outlet 8 to the water tank 7 to realize the water circulation function. A one-way valve is installed on the pipeline between the second four-way valve 17 and the air intake of the secondary compressor 16.

[0050] In one embodiment, the waste heat recovery component includes a temperature-sensitive control valve 20, a fourth heat exchanger 21 and a first pipeline 19. The temperature-sensitive control valve 20, the fourth heat exchanger 21 and the sixth valve 22 are sequentially installed on the first pipeline 19 according to the flow direction of the refrigerant. One end of the first pipeline 19 is connected to the refrigerant outlet end of the second heat exchanger 15, and the other end of the first pipeline 19 is connected to the first end of the third heat exchanger 18. The refrigerant after passing through the second four-way valve 17 exchanges heat with the fourth heat exchanger 21 and then enters the suction port of the secondary compressor 16. A capillary tube is installed on the first pipeline 19 between the fourth heat exchanger 21 and the sixth valve 22, and the fourth heat exchanger 21 can be a shell heat exchanger. In the heating mode, the refrigerant in the first refrigerant pipeline 13 enters the suction port of the secondary compressor 16 after heat exchange through the fourth heat exchanger 21. In the heating mode, the temperature of the gaseous refrigerant increases after passing through the fourth heat exchanger 21. A one-way valve is installed on the first pipeline 19 between the temperature-sensitive control valve 20 and the second heat exchanger 15 .

[0051] In the above embodiment, the temperature difference between the refrigerant entering the fourth heat exchanger 21 and the refrigerant coming out of the fourth heat exchanger 21 is regulated by adjusting the opening of the temperature-sensitive control valve 20, thereby adjusting the suction superheat. Under low-temperature heating conditions, the compressor can be effectively prevented from returning liquid, thereby ensuring the exhaust superheat, providing the basic conditions for high capacity of the unit, and recycling the waste heat of the refrigerant after passing through the second heat exchanger 15, thereby improving energy utilization. The waste heat of the refrigerant is exchanged with the refrigerant before entering the suction port of the secondary compressor 16, thereby increasing the refrigerant temperature at the suction port of the secondary compressor 16, providing the basic conditions for creating high capacity for the secondary compressor 16, and helping the secondary compressor 16 to produce high capacity.

[0052] In one embodiment, the air source heat pump system also includes a second pipeline 24 and a third pipeline 12. The second end of the first heat exchanger 4 is connected to the exhaust port of the secondary compressor 16 through the second pipeline 24, and the first end of the first heat exchanger 4 is connected to the first end of the third heat exchanger 18 through the third pipeline 12. The fourth valve 6 is installed on the second pipeline 24, and the fifth valve 23 is installed on the third pipeline 12. The first heat exchanger 4, the second pipeline 24, the third pipeline 12, the secondary compressor 16 and the second heat exchange component are combined to form a refrigeration system for cooling the circulating water in the water storage tank 7.

[0053] In the above embodiment, when the two-stage air source heat pump system performs cooling, part of the refrigerant enters the first heat exchanger 4, so that the first heat exchanger 4 and the third heat exchanger 18 perform heat exchange together, thereby increasing the heat exchange area and ensuring the cooling capacity.

[0054] It should be noted that the value of the highest frequency increased when the first-stage compressor 1 is started is smaller than the value of the highest frequency increased when the second-stage compressor 16 is started.

[0055] The working principle of the present application is as follows: in the heating mode, the fourth valve 6 and the fifth valve 23 are in the closed state. When the primary air source heat pump system is in the separate heating mode, the secondary air source heat pump system does not work. At this time, the first valve 14, the second valve, the sixth valve 22 and the temperature sensing control valve 20 are all in the closed state, and the third valve 5 is in the open state. Specifically, the high-temperature and high-pressure gaseous refrigerant discharged from the exhaust port of the primary compressor 1 passes through the Venturi ejector 2 and then enters the heat exchange coil through the first four-way valve 3 to exchange heat with the circulating water in the water storage tank 7, so that the temperature of the circulating water increases, and the refrigerant in the heat exchange coil becomes a low-pressure liquid, passes through the electronic expansion valve and becomes a low-pressure liquid refrigerant, and then passes through the first heat exchanger 4 and becomes a low-pressure gaseous refrigerant, and flows back to the suction port of the primary compressor 1 through the first four-way valve 3 to complete the separate heating mode.

[0056] When the secondary air source heat pump system is in the separate heating mode, the primary air source heat pump system does not work. At this time, the first valve 14, the second valve, and the third valve 5 are in the closed state, the sixth valve 22 and the temperature sensing control valve 20 are opened, and the high-temperature and high-pressure gaseous refrigerant discharged from the exhaust port of the secondary compressor 16 is transported to the second heat exchanger 15 through the second four-way valve 17 to exchange heat with the circulating water. A part of the refrigerant after heat exchange is transported to the third heat exchanger 18 after passing through the first pipeline 19, and the other part is transported to the third heat exchanger 18 after passing through the electronic expansion valve. The refrigerant passing through the third heat exchanger 18 is a low-pressure gaseous refrigerant, and then enters the air intake port of the secondary compressor 16 through the second four-way valve 17, and exchanges heat with the fourth heat exchanger 21 before entering the air intake port, thereby increasing the temperature of the refrigerant at the air intake port and completing the separate heating mode.

[0057] When the primary air source heat pump system and the secondary air source heat pump system are in linkage heating mode, Figure 2 As shown, the temperature-sensing control valve 20, the sixth valve 22 and the third valve 5 are all opened, the first-stage compressor 1 and the second-stage compressor 16 are started, and after the start-up is completed, the first valve 14 is started first, and after the preset start-up time, the second valve is started, which helps to guide the refrigerant in the third heat exchanger 18 into the Venturi ejector 2, and part of the high-temperature and high-pressure gaseous refrigerant discharged from the exhaust port of the first-stage compressor 1 enters the suction port of the second-stage compressor 16 through the first refrigerant pipeline 13, which helps to increase the refrigerant temperature at the suction port and play a role in replenishing fluid. The refrigerant in the heat exchanger 18 is partially drained into the venturi ejector 2, creating a lower negative pressure inside the third heat exchanger 18, so that more liquid refrigerant flashes into gaseous refrigerant, ensuring the dryness of the gaseous refrigerant and facilitating the secondary compressor 16 to produce high capacity. The circulating water in the water storage tank 7 is heated once after heat exchange through the heat exchange coil, and then enters the second heat exchanger 15 for heat exchange again to achieve secondary heating. The circulating water after secondary heating is directly transported to the circulating water outlet 8 of the water storage tank 7 for user use, thereby increasing the hot water temperature. The preset time is flexibly designed according to the actual usage. For example, the preset time is 1 minute.

[0058] Cooling mode, such as Figure 3As shown, only the secondary air source heat pump system is working. At this time, the fourth valve 6 and the fifth valve 23 are open, and the first valve 14, the second valve, the third valve 5, the temperature sensing control valve 20 and the sixth valve 22 are in a closed state. When working, the second four-way valve 17 is switched to the cooling mode. A part of the high-temperature and high-pressure gaseous refrigerant discharged from the secondary compressor 16 enters the third heat exchanger 18 through the second four-way valve 17, and the other part enters the first heat exchanger 4 through the first pipeline 19. The refrigerant after heat exchange in the first heat exchanger 4 and heat exchange in the second heat exchanger 15 enters the second heat exchanger 15 to exchange heat with the circulating water, so that the temperature of the circulating water is reduced to achieve the purpose of cooling. The refrigerant after passing through the second heat exchanger 15 flows back to the suction port of the secondary compressor 16 through the second four-way valve 17 to complete the cooling process.

[0059] On the other hand, the present invention further provides an operation control method of an air source heat pump system, the air source heat pump system being the air source heat pump system described in any one of the above technical solutions, the operation control method comprising:

[0060] Receive an instruction to start the air source heat pump system and select a heating mode or a cooling mode according to the instruction;

[0061] In cooling mode, the refrigeration system in the air source heat pump system is controlled to perform cooling;

[0062] In heating mode, the ambient temperature and the outlet water temperature of the water storage tank 7 are obtained;

[0063] If the ambient temperature is greater than or equal to the first preset ambient temperature value, and the outlet water temperature is less than or equal to the first preset value, the primary air source heat pump system is controlled to execute the heating mode, and the secondary air source heat pump system is in the standby state;

[0064] If the outlet water temperature is greater than the first preset value and less than or equal to the second preset value, and the ambient temperature is greater than or equal to the first preset ambient temperature value or the ambient temperature is greater than or equal to the second preset ambient temperature value and less than the first preset ambient temperature value, the secondary air source heat pump system is controlled to execute the heating mode, and the primary air source heat pump system is in the standby state;

[0065] If the water outlet temperature is greater than the first preset value and less than or equal to the second preset value, and the ambient temperature is greater than or equal to the third preset ambient temperature value and less than the second preset ambient temperature value, the primary air source heat pump system and the secondary air source heat pump system are controlled to execute the linkage heating mode.

[0066] In the above embodiment, in the heating mode, the present invention can automatically control the working states of the primary air source heat pump system and the secondary air source heat pump system according to different working conditions, with a high degree of intelligence, so as to achieve the purpose of providing stable heat for users.

[0067] It should be noted that the water outlet temperature of the water storage tank 7 refers to the water temperature of the circulating water outlet 8 for delivery to the user. Regarding the specific values ​​of the first preset ambient temperature, the second preset ambient temperature, the third preset ambient temperature, the first preset value and the second preset value, this application does not make specific restrictions, and they are flexibly set according to actual use conditions. For example, the first preset ambient temperature is 0°C, the second preset ambient temperature is -25°C, the third preset ambient temperature is -45°C, the first preset value is 35°C, and the second preset value is 60°C.

[0068] In one embodiment, the air source heat pump system pre-stores a plurality of preset refrigerant temperature difference values ​​corresponding to different ambient temperatures, and the operation control method further includes:

[0069] According to the ambient temperature, the opening of the temperature-sensing control valve 20 is controlled to adjust the refrigerant temperature difference between the inlet and outlet ends of the fourth heat exchanger 21 .

[0070] In the above embodiment, the suction superheat is adjusted by controlling the opening of the temperature-sensitive control valve 20 to ensure the suction superheat. Under low-temperature heating conditions, liquid return of the compressor can be effectively prevented, thereby ensuring the exhaust superheat and providing the basic conditions for high capacity of the unit.

[0071] This application does not specifically limit the preset refrigerant temperature difference values ​​corresponding to multiple different ambient temperatures, and it can be flexibly set according to actual usage. For example, when the ambient temperature is between -25℃ and 0℃, the refrigerant temperature difference is 5℃; when the ambient temperature is between -35℃ and -25℃, the refrigerant temperature difference is 15℃; when the ambient temperature is between -45℃ and -35℃, the refrigerant temperature difference is 25℃.

[0072] In the various embodiments and various expanded implementations described above, under conditions with low capacity requirements, heating is only performed through the primary air source heat pump system to avoid overheating waste; when the operating temperature is above -20°C, only the secondary air source heat pump system can be turned on for heating; in harsh ultra-low temperature environments, the primary air source heat pump system and the secondary air source heat pump system are turned on for a linked heating mode, and dual compressor technology is used to provide stable power for the heat pump unit, thereby achieving the purpose of providing users with stable heat and reducing user usage costs.

[0073] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. An air source heat pump system, characterized in that: The air source heat pump system includes a primary air source heat pump system, a secondary air source heat pump system and a water tank. The primary air source heat pump system and the secondary air source heat pump system are configured to heat the circulating water in the water tank in a separate heating mode or a linked heating mode. In the linked heating mode, the circulating water in the water tank heated by the primary air source heat pump system is heated again by the secondary air source heat pump system and then delivered to the user.

2. The air source heat pump system according to claim 1, characterized in that: The air source heat pump system also includes a first refrigerant pipeline and a second refrigerant pipeline. In the heating mode, part of the refrigerant discharged from the exhaust port of the primary air source heat pump system can be transported to the intake port of the secondary air source heat pump system through the first refrigerant pipeline, and part of the refrigerant in the secondary air source heat pump system that has undergone heat exchange with the circulating water in the water storage tank is transported to the primary air source heat pump system through the second refrigerant pipeline. A first valve is installed on the first refrigerant pipeline, and a second valve is installed on the second refrigerant pipeline.

3. The air source heat pump system according to claim 2, characterized in that: The primary air source heat pump system includes a primary compressor, a venturi ejector and a first heat exchange component. The exhaust port of the primary compressor is connected to the air inlet of the venturi ejector, and the air outlet of the venturi ejector is connected to the air intake port of the primary compressor through the first heat exchange component. The venturi ejector guides the refrigerant at the outlet end of the secondary air source heat pump system serving as an evaporator in the heating mode into the venturi ejector through the second refrigerant pipeline to reduce the negative pressure of the evaporator.

4. The air source heat pump system according to claim 3, characterized in that: The first heat exchange component includes a heat exchange coil, a first heat exchanger and a first four-way valve. The heat exchange coil is arranged on the water tank. The air outlet of the venturi ejector is connected to the first end of the first heat exchanger through the first four-way valve and the heat exchange coil. The second end of the first heat exchanger is connected to the suction port of the first-stage compressor through the first four-way valve. A third valve is arranged between the first heat exchanger and the first four-way valve.

5. The air source heat pump system according to any one of claims 2 to 4, characterized in that: The secondary air source heat pump system includes a secondary compressor, a second heat exchange component and a waste heat recovery component. The second heat exchange component is arranged between the exhaust port and the air intake port of the secondary compressor. The second heat exchange component can exchange heat with the circulating water in the water storage tank. The waste heat recovery component is used to recover the waste heat of the refrigerant after the second heat exchange component exchanges heat with the circulating water in the water storage tank in the heating mode and to perform heat exchange with the refrigerant entering the air intake port of the secondary compressor.

6. The air source heat pump system according to claim 5, characterized in that: The second heat exchange component includes a second heat exchanger, a third heat exchanger and a second four-way valve. The exhaust port of the secondary compressor is connected to the first end of the third heat exchanger through the second four-way valve and the second heat exchanger. The second end of the third heat exchanger is connected to the intake port of the secondary compressor through the second four-way valve. The other end of the second refrigerant pipeline is connected to the second end of the third heat exchanger. In the heating mode, the third heat exchanger is an evaporator.

7. The air source heat pump system according to claim 6, characterized in that: The waste heat recovery component includes a temperature-sensitive control valve, a fourth heat exchanger and a first pipeline. The temperature-sensitive control valve, the fourth heat exchanger and the sixth valve are installed on the first pipeline in sequence according to the flow direction of the refrigerant. One end of the first pipeline is connected to the refrigerant outlet end on the second heat exchanger, and the other end of the first pipeline is connected to the first end of the third heat exchanger. The refrigerant after passing through the second four-way valve exchanges heat with the fourth heat exchanger and then enters the suction port of the secondary compressor.

8. The air source heat pump system according to claim 6, characterized in that: The air source heat pump system also includes a second pipeline and a third pipeline. The second end of the first heat exchanger is connected to the exhaust port of the secondary compressor through the second pipeline, and the first end of the first heat exchanger is connected to the first end of the third heat exchanger through the third pipeline. A fourth valve is installed on the second pipeline, and a fifth valve is installed on the third pipeline. The first heat exchanger, the second pipeline, the third pipeline, the secondary compressor and the second heat exchange component are combined to form a refrigeration system for cooling the circulating water in the water storage tank.

9. An operation control method of an air source heat pump system, characterized in that: The air source heat pump system is the air source heat pump system according to any one of claims 1 to 8, and the operation control method comprises: In heating mode, obtain the ambient temperature and the water outlet temperature of the water storage tank; If the ambient temperature is greater than or equal to a first preset ambient temperature value, and the outlet water temperature is less than or equal to a first preset value, the primary air source heat pump system is controlled to execute a heating mode, and the secondary air source heat pump system is in a standby state; and / or If the outlet water temperature is greater than a first preset value and less than or equal to a second preset value, and the ambient temperature is greater than or equal to the first preset ambient temperature value or the ambient temperature is greater than or equal to the second preset ambient temperature value and less than the first preset ambient temperature value, the secondary air source heat pump system is controlled to execute a heating mode, and the primary air source heat pump system is in a standby state; and / or If the water outlet temperature is greater than the first preset value and less than or equal to the second preset value, and the ambient temperature is greater than or equal to the third preset ambient temperature value and less than the second preset ambient temperature value, the primary air source heat pump system and the secondary air source heat pump system are controlled to execute the linkage heating mode.

10. The operation control method of the air source heat pump system according to claim 9 referring to claim 7, characterized in that: The air source heat pump system pre-stores a plurality of preset refrigerant temperature difference values ​​corresponding to different ambient temperatures, and the operation control method further includes: According to the size of the ambient temperature, the opening of the temperature-sensing control valve is controlled to adjust the refrigerant temperature difference between the inlet and outlet ends of the fourth heat exchanger.

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