Heat pump system and control method and control device thereof

Abstract

The invention provides a heat pump system and a control method and device thereof. The heat pump system comprises a first compressor, a second compressor, a four-way valve, a second heat exchanger, an ejector and a gas-liquid separator, the first compressor, the second compressor, the four-way valve, the second heat exchanger, the ejector and the gas-liquid separator are connected through a refrigerant main path, the first compressor and the second compressor are connected in series, and a gas outlet of the gas-liquid separator communicates with a gas suction port of the first compressor; an outlet and a liquid inlet of the ejector are respectively communicated with an inlet of the gas-liquid separator and the second heat exchanger, a gas inlet of the ejector is communicated with a gas outlet of the gas-liquid separator through an ejection branch, and a first heat exchanger is arranged on the ejection branch. According to the heat pump system and the control method and device thereof, the two-stage compression and injection enthalpy increasing technology is utilized, and efficient and stable heating performance and energy efficiency ratio improvement in the low-temperature environment are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical appliances, and particularly to a heat pump system, a control method thereof, and a control device thereof. Background Art

[0002] In the related art, the existing compressor displacement and high-low pressure ratio are limited. In the case of low outdoor ambient temperature, the heating capacity and energy efficiency ratio of the air-conditioning system decay greatly. To improve the low-temperature heating capacity and energy efficiency ratio of the unit, a compressor with a larger displacement and a larger high-low pressure ratio is required. However, this leads to difficulty in further improving the heating performance of the air-conditioning system. Currently, multi-connected air-conditioning systems often use gas-injected enhanced enthalpy compressors to improve the heating capacity in low-temperature environments. Due to the limitations of displacement and compression ratio, the enhancement of enthalpy has limited effect on improving the heating capacity and energy efficiency ratio. Summary of the Invention

[0003] The present invention provides a heat pump system, a control method thereof, and a control device thereof to solve the defects existing in the prior art and achieve the following technical effects: By using the two-stage compression and ejector enhanced enthalpy technologies, high-efficiency and stable heating performance and energy efficiency ratio improvement in low-temperature environments are realized.

[0004] The heat pump system according to the first aspect embodiment of the present invention includes: A first compressor, a second compressor, a four-way valve, a second heat exchanger, an ejector, and a gas-liquid separator connected through a main refrigerant circuit, wherein the first compressor and the second compressor are connected in series, and the gas outlet of the gas-liquid separator is communicated with the suction port of the first compressor; The outlet and the liquid inlet of the ejector are respectively communicated with the inlet of the gas-liquid separator and the second heat exchanger, and the gas inlet of the ejector is communicated with the gas outlet of the gas-liquid separator through an ejector branch, and a first heat exchanger is provided on the ejector branch.

[0005] According to an embodiment of the present invention, it further includes a gas-injected enhanced enthalpy device, which includes an enhanced enthalpy heat exchanger, an enhanced enthalpy expansion valve, and an enhanced enthalpy branch. The two ends of the enhanced enthalpy branch are respectively communicated with the second heat exchanger and the suction port of the second compressor, the enhanced enthalpy expansion valve is provided on the enhanced enthalpy branch, and the enhanced enthalpy branch flows through the enhanced enthalpy heat exchanger, and the enhanced enthalpy heat exchanger is located between the second heat exchanger and the liquid inlet of the ejector.

[0006] In this way, the gas-injected enhanced enthalpy device is particularly important in extremely low temperatures. It effectively increases the enthalpy value of the refrigerant entering the second-stage compressor, ensuring sufficient heating capacity even when the external ambient temperature is very low, and solving the problem of the sharp decline in heating capacity of traditional heat pump systems at low temperatures.

[0007] According to an embodiment of the present invention, the ejector branch is communicated with the main refrigerant path through a first branch and a second branch respectively. A first solenoid valve is provided on the first branch, a second solenoid valve is provided on the ejector branch, and a third solenoid valve is provided on the second branch; And in the refrigeration mode, the first branch is located upstream of the inlet of the first heat exchanger, the second branch is located downstream of the outlet of the first heat exchanger. A fourth solenoid valve is provided on the main refrigerant path between the second branch and the liquid inlet of the ejector, and a fifth solenoid valve is provided on the main refrigerant path between the first branch and the outlet of the ejector.

[0008] In this way, by controlling the opening and closing of the first solenoid valve, the second solenoid valve, the third solenoid valve and the fourth solenoid valve, the switching between the heating mode and the refrigeration mode can be realized.

[0009] According to an embodiment of the present invention, a first expansion valve is provided on the main refrigerant path, and a first check valve is connected in parallel with the first expansion valve; a second expansion valve is provided on the ejector branch, and a second check valve is connected in parallel with the second expansion valve.

[0010] In this way, by adding expansion valves and check valves at key positions in the present invention, not only the precise control ability of the refrigerant flow rate in the refrigeration and heating modes of the system is improved, but also the reliability and safety of the system are enhanced.

[0011] According to an embodiment of the present invention, a seventh solenoid valve is connected in parallel at both ends of the first compressor, and a sixth solenoid valve is connected in parallel at both ends of the second compressor.

[0012] In this way, by controlling the switching of the compressor working mode through the sixth solenoid valve and the seventh solenoid valve, the system can better adapt to the load changes in different seasons or different time periods. It can not only provide sufficient cooling or heating capacity under extreme weather conditions, but also maintain efficient operation under light load and reduce unnecessary energy consumption.

[0013] According to an embodiment of the present invention, an intermediate heat exchanger is provided between the outlet of the gas-liquid separator and the suction port of the first compressor, and the main refrigerant path flows through the intermediate heat exchanger.

[0014] In this way, in the refrigeration mode, the intermediate heat exchanger helps to increase the subcooling degree of the refrigerant, and in the heating mode, it can be used as one of the auxiliary heating ways to improve the overall heating capacity through the heat exchange between refrigerants. In this way, the system can maintain efficient and stable performance under different working conditions.

[0015] According to an embodiment of the second aspect of the present invention, a control method for the heat pump system based on the embodiment of the first aspect of the present invention includes: Receive a working instruction for controlling the working mode of the heat pump system, and determine the to-be-operated mode of the heat pump system; According to the to-be-operated mode, control and adjust the opening degrees of each solenoid valve to control the heat pump system to enter the to-be-operated mode.

[0016] According to an embodiment of the present invention, the step of controlling and adjusting the opening degrees of each solenoid valve according to the to-be-operated mode to control the heat pump system to enter the to-be-operated mode specifically includes: When the to-be-operated mode is the heating mode, control the second solenoid valve, the fourth solenoid valve, and the fifth solenoid valve to open, and control the first solenoid valve and the third solenoid valve to close; When the to-be-operated mode is the cooling mode, control the first solenoid valve and the third solenoid valve to open, and control the second solenoid valve and the fourth solenoid valve to close.

[0017] In this way, through the instant control of the solenoid valve, the system can quickly respond to the changes in the external environment or user needs, seamlessly transition from the heating mode to the cooling mode or vice versa, improving the user experience.

[0018] According to an embodiment of the present invention, it further includes: Obtain the load demand of the heat pump system; According to the load demand, control and adjust the opening degrees of the sixth solenoid valve and the seventh solenoid valve to switch the single-stage and double-stage compression modes; preferably, the displacement of the first compressor is higher than that of the second compressor, then when the load demand is in the first load range, control the sixth solenoid valve to close and the seventh solenoid valve to open; when the load demand is in the second load range, control the sixth solenoid valve to open and the seventh solenoid valve to close; when the load demand is in the third load range, control both the sixth solenoid valve and the seventh solenoid valve to close, where the first load range is less than the second load range, and the second load range is less than the third load range.

[0019] In this way, by precisely matching the working state of the compressor with the actual load, the low-efficiency operation of the large compressor at low loads is avoided, thereby significantly improving the overall energy efficiency ratio of the system and reducing the operating cost.

[0020] The control device of the heat pump system according to the third aspect embodiment of the present invention based on the first aspect embodiment of the present invention includes: An acquisition module, configured to receive a working instruction for controlling the working mode of the heat pump system and determine the to-be-operated mode of the heat pump system; A control module, configured to control and adjust the opening degrees of each solenoid valve according to the to-be-operated mode to control the heat pump system to enter the to-be-operated mode.

[0021] The present invention provides a heat pump system, which utilizes two-stage compression and ejector enthalpy-increasing technology to achieve high-efficiency and stable heating performance and improved energy efficiency ratio in a low-temperature environment. Compared with the related technologies, the present invention has at least the following advantages.

[0022] (1) Greatly improve the heating capacity at low temperatures: The two-stage compression technology overcomes the problems of limited displacement and compression ratio of a single-stage compressor at low ambient temperatures. Through continuous compression in two stages, the total displacement and high-low pressure ratio of the compressor are significantly increased, so that a more powerful heating capacity can be output even under extremely cold conditions.

[0023] (2) Enhance the energy efficiency ratio: The ejector enthalpy-increasing technology forms a medium-pressure refrigerant mixture by ejecting high-pressure liquid refrigerant into low-pressure gaseous refrigerant. This process not only increases the enthalpy value of the refrigerant, but also improves the energy efficiency ratio of the entire system. Without significantly increasing the system energy consumption, a remarkable improvement in heating efficiency is achieved.

[0024] (3) Optimize the system response speed and stability: The two-stage compression system can flexibly adjust the working mode according to the load demand. With the intelligent single-double stage compression switching, the system can quickly adapt to the changes in the external environment, ensuring stable operation and high-efficiency output under various working conditions.

[0025] (4) Improve the system adaptability and reliability: The combination of two-stage compression and ejector enthalpy-increasing not only enhances the heating capacity of the system in a low-temperature environment, but also improves the system's adaptability to complex environments and the reliability of long-term operation by optimizing the refrigerant circulation path and pressure control.

[0026] In summary, the integrated innovation of two-stage compression and ejector enthalpy-increasing brings excellent heating performance and energy efficiency ratio to the heat pump system in a low-temperature environment, while ensuring the high-efficiency and stable operation of the system, which is an ideal solution to meet the heating needs in cold regions. Brief Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1 It is a schematic structural diagram of a heat pump system provided by an embodiment of the present invention.

[0029] Figure 2 It is a schematic structural diagram of a heat pump system provided by another embodiment of the present invention.

[0030] Figure 3 It is a schematic flow chart of the control method of the heat pump system provided by the present invention.

[0031] Figure 4 It is a schematic structural diagram of the control device of the heat pump system provided by the present invention.

[0032] Figure 5 It is a schematic structural diagram of the electronic device provided by the present invention. Description of the Drawings

[0033] 1. First compressor; 2. Second compressor; 3. Four-way valve; 4. First heat exchanger; 5. Second heat exchanger; 6. Ejector; 7. Gas-liquid separator; 8. Enthalpy-increasing heat exchanger; 9. Enthalpy-increasing expansion valve; 10. Enthalpy-increasing branch; 11. Main refrigerant circuit; 12. Ejector branch; 13. First branch; 14. Second branch; 15. First solenoid valve; 16. Second solenoid valve; 17. Third solenoid valve; 18. Fourth solenoid valve; 19. Fifth solenoid valve; 20. Sixth solenoid valve; 21. Seventh solenoid valve; 22. First expansion valve; 23. First check valve; 24. Second expansion valve; 25. Second check valve; 26. Intermediate heat exchanger. Detailed Embodiments

[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without making creative efforts based on the embodiments in the present invention fall within the protection scope of the present invention.

[0035] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without conflict, those skilled in the art may combine the different embodiments or examples described in this specification and the features of the different embodiments or examples.

[0036] As Figure 1 and Figure 2 shown, the heat pump system according to the first aspect embodiment of the present invention includes a first compressor 1, a second compressor 2, a four-way valve 3, a second heat exchanger 5, an ejector 6, and a gas-liquid separator 7.

[0037] The first compressor 1, the second compressor 2, the four-way valve 3, the second heat exchanger 5, the ejector 6 and the gas-liquid separator 7 are connected through the main refrigerant circuit 11. Among them, the first compressor 1 and the second compressor 2 are connected in series, and the gas outlet of the gas-liquid separator 7 is communicated with the suction port of the first compressor 1.

[0038] The outlet and the liquid inlet of the ejector 6 are respectively communicated with the inlet of the gas-liquid separator 7 and the second heat exchanger 5. There is a communication through the ejector branch 12 between the gas inlet of the ejector 6 and the gas outlet of the gas-liquid separator 7, and a first heat exchanger 4 is provided on the ejector branch 12.

[0039] It can be understood that in the invention, a two-stage compression mechanism and an ejector enthalpy-increasing technology are applied to optimize the heating effect in a low-temperature environment. Specifically, on the one hand: the core of the system lies in the adoption of a two-stage compressor arrangement, where the first compressor 1 and the second compressor 2 work in series. The first compressor 1 first performs preliminary compression to increase the pressure of the refrigerant, and then the refrigerant enters the second compressor 2 for secondary compression to reach a higher pressure level. Such a design enables the system to maintain a relatively high refrigerant pressure even at a relatively low outdoor temperature, thereby improving the heating efficiency.

[0040] On the other hand, the ejector 6 plays a key role in the system. It extracts the already compressed gaseous refrigerant (i.e., the "ejector gas") from the gas-liquid separator 7 and injects this part of the gaseous refrigerant into the low-temperature and low-pressure liquid refrigerant flowing out of the second heat exchanger 5 to form a mixed medium-pressure refrigerant. This process is similar to a small-scale pressurization process, which can significantly increase the enthalpy value of the refrigerant entering the first compressor 1, thereby improving the heating capacity of the system.

[0041] In addition, the gas-liquid separator 7 is responsible for separating the gaseous and liquid phases in the mixed refrigerant. The gaseous part returns to the inlet of the first compressor 1 through the ejector branch 12, while the liquid part undergoes throttling through the electronic expansion valve and evaporates in the first heat exchanger 4 to absorb heat. This cycle ensures the efficient flow and energy conversion of the refrigerant in the system.

[0042] For the heat pump system according to an embodiment of the present invention, its specific working process (taking the heating cycle as an example) is as follows.

[0043] The first expansion valve 22 is closed, the second expansion valve 24 and the enthalpy-increasing expansion valve 9 are opened, the first solenoid valve 15, the third solenoid valve 17, the sixth solenoid valve 20 and the seventh solenoid valve 21 are closed, and the second solenoid valve 16, the fourth solenoid valve 18 and the fifth solenoid valve 19 are opened. At this time, the high-pressure gaseous refrigerant at the outlet of the second compressor 2 flows to the second heat exchanger 5 and condenses into a liquid state.

[0044] After the liquid refrigerant passes through the check valve, a part of it enters the second heat exchanger 5 to exchange heat with the two-phase refrigerant after throttling by the enthalpy-increasing expansion valve 9, and is further subcooled. The subcooled high-pressure liquid refrigerant enters the ejector 6 through the fourth solenoid valve 18. At the same time, the ejector 6 sucks in the low-pressure gaseous refrigerant at the outlet of the gas-liquid separator 7. After mixing, a medium-pressure refrigerant is formed and enters the gas-liquid separator 7 through the fifth solenoid valve 19.

[0045] Meanwhile, the gaseous refrigerant separated by the gas-liquid separator 7 returns to the first compressor 1 through the return air pipe, while the liquid refrigerant is throttled by the second expansion valve 24 and evaporates in the first heat exchanger 4, and then enters the ejector 6 again. The two-phase refrigerant in the second heat exchanger 5 is heated into superheated gas, and after being mixed with the superheated gas at the outlet of the first compressor 1, they enter the second compressor 2 together for secondary compression.

[0046] It should be noted that according to the system load demand, by opening or closing the sixth solenoid valve 20 and the seventh solenoid valve 21, the single-stage and double-stage compression modes can be flexibly switched to adapt to different working conditions and improve the flexibility and energy efficiency of the system operation.

[0047] In summary, through the double-stage compression, ejector enthalpy-increasing, subcooling technology and flexible load regulation mechanism, this heat pump system realizes efficient and stable heating performance and improved energy efficiency ratio in low-temperature environments.

[0048] In related technologies, the existing compressor displacement and high-low pressure ratio are limited. In the case of low outdoor ambient temperature, the heating capacity and energy efficiency ratio of the air-conditioning system decay greatly. To improve the low-temperature heating capacity and energy efficiency ratio of the unit, a compressor with a larger displacement and a larger high-low pressure ratio is required. However, this leads to difficulty in further improving the heating performance of the air-conditioning system. Currently, multi-connected air-conditioning systems often use air-increasing enthalpy compressors to improve the heating capacity in low-temperature environments. Due to the limitations of displacement and compression ratio, the enthalpy increase has limited improvement on the heating capacity and energy efficiency ratio.

[0049] Therefore, to solve the technical defects existing in the above-mentioned related technologies, the present invention provides a heat pump system, which uses double-stage compression and ejector enthalpy-increasing technologies to achieve efficient and stable heating performance and improved energy efficiency ratio in low-temperature environments. Compared with the related technologies, the present invention has at least the following advantages.

[0050] (1) Greatly improve the low-temperature heating capacity: The double-stage compression technology overcomes the problems of limited displacement and compression ratio of the single-stage compressor at low ambient temperatures. Through two consecutive compression stages, the total displacement and high-low pressure ratio of the compressor are significantly improved, so that a more powerful heating capacity can be output even under extremely cold conditions.

[0051] (2)Enhanced energy efficiency ratio: The ejector enthalpy-increasing technology forms a medium-pressure refrigerant mixture by ejecting high-pressure liquid refrigerant with low-pressure gaseous refrigerant. This process not only increases the enthalpy value of the refrigerant but also improves the energy efficiency ratio of the entire system. Without significantly increasing the system energy consumption, a remarkable improvement in heating efficiency is achieved.

[0052] (3)Optimized system response speed and stability: The two-stage compression system can flexibly adjust the working mode according to the load demand. With the intelligent single-double stage compression switching, the system can quickly adapt to the changes in the external environment, ensuring stable operation and efficient output under various working conditions.

[0053] (4)Improved system adaptability and reliability: The combination of two-stage compression and ejector enthalpy-increasing not only enhances the heating capacity of the system in low-temperature environments but also improves the system's adaptability to complex environments and the reliability of long-term operation by optimizing the refrigerant circulation path and pressure control.

[0054] In summary, the integrated innovation of two-stage compression and ejector enthalpy-increasing brings excellent heating performance and energy efficiency ratio to the heat pump system in low-temperature environments, while ensuring the high-efficiency and stable operation of the system, which is an ideal solution to meet the heating needs in cold regions.

[0055] As Figure 1 shown, according to some embodiments of the present invention, it further includes an air-increasing enthalpy device. The air-increasing enthalpy device includes an enthalpy-increasing heat exchanger 8, an enthalpy-increasing expansion valve 9, and an enthalpy-increasing branch 10. Both ends of the enthalpy-increasing branch 10 are respectively connected to the second heat exchanger 5 and the suction port of the second compressor 2. The enthalpy-increasing expansion valve 9 is provided on the enthalpy-increasing branch 10, and the enthalpy-increasing branch 10 flows through the enthalpy-increasing heat exchanger 8. The enthalpy-increasing heat exchanger 8 is located between the second heat exchanger 5 and the liquid inlet of the ejector 6.

[0056] In this embodiment, based on the original two-stage compression and ejector enthalpy-increasing, the heat pump system of the present invention also integrates an air-increasing enthalpy device, further strengthening its ability to provide efficient heating in low-temperature environments. This air-increasing enthalpy device mainly consists of an enthalpy-increasing heat exchanger 8, an enthalpy-increasing expansion valve 9, and an enthalpy-increasing branch 10. The working principle of the air-increasing enthalpy device is as follows.

[0057] The enthalpy-increasing branch 10 connects the second heat exchanger 5 and the suction end of the second compressor 2, forming an additional refrigerant circulation path. The addition of this path enables part of the high-pressure liquid refrigerant that has been subcooled by the second heat exchanger 5 to be further throttled through the enthalpy-increasing expansion valve 9 to become a two-phase refrigerant, and then flow through the enthalpy-increasing heat exchanger 8.

[0058] The enthalpy - increasing heat exchanger 8 located between the second heat exchanger 5 and the liquid inlet of the ejector 6 enables the two - phase refrigerant in the enthalpy - increasing branch 10 to exchange heat with the refrigerant in other parts of the system. In this way, the refrigerant about to enter the second compressor 2 has its temperature reduced and its superheat degree decreased after passing through the enthalpy - increasing heat exchanger 8, thereby increasing its enthalpy value during the compression process, that is, "enthalpy - increasing".

[0059] The reasonable control of the enthalpy - increasing expansion valve 9 enables the refrigerant entering the second compressor 2 to be in a more suitable two - phase state, which not only improves the compression efficiency but also reduces the ineffective power consumption during the compression process, further improving the energy efficiency ratio of the system.

[0060] In this way, the gas - injection enthalpy - increasing device is particularly important at extremely low temperatures. It effectively increases the enthalpy value of the refrigerant entering the second - stage compressor, ensuring sufficient heating capacity even when the external ambient temperature is very low, and solving the problem that the heating capacity of traditional heat pump systems drops sharply at low temperatures. At the same time, through fine heat exchange and pressure control, the gas - injection enthalpy - increasing mechanism enables the system to maintain or reduce energy consumption while increasing the heating capacity, so the energy efficiency ratio is significantly improved.

[0061] In addition, the device makes the whole system operate more stably by optimizing the refrigerant circulation path and state, and can maintain good heating effect and energy efficiency performance even under large load fluctuations.

[0062] As Figure 1 shown, according to some embodiments of the present invention, the ejector branch 12 is respectively communicated with the refrigerant main path 11 through the first branch 13 and the second branch 14. A first solenoid valve 15 is provided on the first branch 13, a second solenoid valve 16 is provided on the ejector branch 12, and a third solenoid valve 17 is provided on the second branch 14.

[0063] And in the refrigeration mode, the first branch 13 is upstream of the inlet of the first heat exchanger 4, the second branch 14 is downstream of the outlet of the first heat exchanger 4. A fourth solenoid valve 18 is provided on the refrigerant main path 11 between the second branch 14 and the liquid inlet of the ejector 6, and a fifth solenoid valve 19 is provided on the refrigerant main path 11 between the first branch 13 and the outlet of the ejector 6.

[0064] In this way, by controlling the opening and closing of the first solenoid valve 15, the second solenoid valve 16, the third solenoid valve 17 and the fourth solenoid valve 18, the switching between the heating mode and the refrigeration mode can be realized. Through the specific opening and closing configurations of these valves, the system can achieve the directional flow of the refrigerant in the heating and refrigeration modes, thereby completing different heat exchange processes to meet the heating or refrigeration requirements. In the heating mode, through specific valve operations, the refrigerant is guided for enthalpy - increasing treatment and effective heat energy conversion, while in the refrigeration mode, it ensures the refrigerant circulation to achieve the effect of cooling.

[0065] For example Figure 1 As shown, when the mode to be run is the heating mode, the second solenoid valve 16, the fourth solenoid valve 18 and the fifth solenoid valve 19 are controlled to open, and the first solenoid valve 15 and the third solenoid valve 17 are controlled to close. When the mode to be run is the cooling mode, the first solenoid valve 15 and the third solenoid valve 17 are controlled to open, and the second solenoid valve 16 and the fourth solenoid valve 18 are controlled to close.

[0066] As Figure 1 As shown, according to some embodiments of the present invention, a first expansion valve 22 is provided on the main refrigerant path 11, and a first check valve 23 is connected in parallel with the first expansion valve 22; a second expansion valve 24 is provided on the ejector branch 12, and a second check valve 25 is connected in parallel with the second expansion valve 24.

[0067] It can be understood that the first expansion valve 22 is located on the main refrigerant path 11 and is mainly responsible for regulating the refrigerant flow rate into the first heat exchanger 4 (usually an evaporator). By precisely controlling the throttling effect, it can throttle and depressurize the high-pressure liquid refrigerant into a low-pressure two-phase refrigerant, ensuring effective absorption of external heat for evaporation in the heat exchanger, which is a key step in the refrigeration cycle of a refrigeration or heat pump system.

[0068] The first check valve 23 is connected in parallel with the first expansion valve 22, and its main function is to prevent refrigerant backflow, ensure the correct refrigerant flow direction, protect the compressor from damage caused by high-pressure refrigerant backflow, and maintain the stability of the internal pressure of the system.

[0069] The second expansion valve 24 is provided on the ejector branch 12. This design is used to further refine the refrigerant flow control, especially before passing through the ejector 6. It helps to precisely regulate the refrigerant dosage entering the ejector 6, so as to better mix with the low-pressure gaseous refrigerant from the gas-liquid separator 7 to form a medium-pressure refrigerant. This process is crucial for improving the system efficiency and heating capacity.

[0070] The second check valve 25 is installed in parallel with the second expansion valve 24, and also plays a role in preventing backflow, ensuring that the refrigerant flows along the designed path, and maintaining the stability and efficiency of the system cycle.

[0071] In this way, by adding expansion valves and check valves at key positions, the present invention not only improves the precise control ability of the refrigerant flow rate in the refrigeration and heating modes, but also enhances the reliability and safety of the system, while optimizing the heat exchange efficiency and the overall energy efficiency ratio of the system. Especially in a low-temperature environment, it can significantly improve the heating performance and energy utilization efficiency of the heat pump system.

[0072] As Figure 1As shown, according to some embodiments of the present invention, a seventh solenoid valve 21 is connected in parallel at both ends of the first compressor 1, and a sixth solenoid valve 20 is connected in parallel at both ends of the second compressor 2.

[0073] In this embodiment, the seventh solenoid valve 21 is connected in parallel at both ends of the first compressor 1, and the sixth solenoid valve 20 is connected in parallel at both ends of the second compressor 2. Through the coordinated control of these two groups of solenoid valves, it is possible to flexibly determine whether to enable the two-stage compression mode according to the system load demand or operating conditions. When the system load is high and stronger heating or cooling capacity is required, the solenoid valves will ensure that both compressors work simultaneously to achieve two-stage compression, so as to improve the output power and efficiency of the system. On the contrary, when the load is light, only one compressor can be used, and by closing the corresponding solenoid valve, the single-stage compression mode can be entered to save energy.

[0074] In this way, by controlling the switching of the compressor operating mode through the sixth solenoid valve 20 and the seventh solenoid valve 21, the system can better adapt to the load changes in different seasons or different time periods, can not only provide sufficient cooling or heating capacity under extreme weather conditions, but also maintain efficient operation under light load, reducing unnecessary energy consumption.

[0075] In addition, the control logic of the solenoid valve can also integrate a fault protection mechanism. In case of abnormal or overloaded compressors, the corresponding solenoid valve can be closed to isolate the faulty compressor, preventing the entire system from being affected and facilitating maintenance at the same time.

[0076] As Figure 2 shown, according to some embodiments of the present invention, an intermediate heat exchanger 26 is provided between the outlet of the gas-liquid separator 7 and the suction port of the first compressor 1, and the main refrigerant circuit 11 flows through the intermediate heat exchanger 26.

[0077] It can be understood that the intermediate heat exchanger 26 can play the following roles and advantages.

[0078] (1) Improve system efficiency: The intermediate heat exchanger 26 can utilize the different states of the refrigerant in the cycle (such as the heat exchange between high-pressure liquid refrigerant and low-pressure gaseous refrigerant) to recover and utilize waste heat, thereby reducing the dependence on external energy and improving the energy efficiency ratio of the entire system.

[0079] (2) Enhance the subcooling effect of the refrigerant: During the process of the refrigerant flowing through the intermediate heat exchanger 26, the high-pressure liquid refrigerant can further release heat to the low-pressure gaseous refrigerant about to enter the first compressor 1. This not only increases the subcooling degree of the refrigerant, but also makes the temperature of the refrigerant entering the first-stage compressor lower, thus reducing unnecessary overheating during the compression process and improving the compression efficiency.

[0080] (3) Balance system pressure and temperature: The intermediate heat exchanger 26 serves as a heat balance link within the system, helping to regulate and balance the pressure and temperature of the refrigerant in different parts. This is crucial for maintaining the stable operation of the system and preventing local overheating or overcooling phenomena.

[0081] (4) Optimize refrigeration / heating performance: In the refrigeration mode, the intermediate heat exchanger 26 helps to increase the subcooling degree of the refrigerant. In the heating mode, it can serve as one of the ways of auxiliary heating, improving the overall heating capacity through heat exchange between the refrigerants. In this way, the system can maintain efficient and stable performance under different working conditions.

[0082] (5) Enhance system flexibility: By setting up the intermediate heat exchanger 26, the circulation path and state of the refrigerant can be adjusted more flexibly, providing additional adjustment means for the system to adapt to a wider range of operating conditions and external environment changes.

[0083] According to some embodiments of the present invention, the refrigerant in the heat pump system can adopt R1270.

[0084] A specific embodiment of the heat pump system of the present invention is given below.

[0085] As Figure 1 shown, in the heating mode, the first expansion valve 22 is closed, and the second expansion valve 24 and the enthalpy-increasing expansion valve 9 are opened. The first solenoid valve 15, the third solenoid valve 17, the sixth solenoid valve 20, and the seventh solenoid valve 21 are closed, and the second solenoid valve 16, the fourth solenoid valve 18, and the fifth solenoid valve 19 are opened.

[0086] The high-pressure gaseous refrigerant at the outlet of the second compressor 2 flows through the second heat exchanger 5 and condenses into a liquid state. Through the check valve, a part of it enters the enthalpy-increasing heat exchanger 8 to exchange heat with the two-phase refrigerant throttled by the enthalpy-increasing expansion valve 9. The further subcooled high-pressure liquid refrigerant enters the ejector 6 through the fourth solenoid valve 18. The low-pressure gaseous refrigerant at the outlet of the first heat exchanger 4, the mixed medium-pressure refrigerant enters the gas-liquid separator 7 through the fifth solenoid valve 19. The gaseous refrigerant returns to the first compressor 1 through the return pipe, and the liquid refrigerant passes through the second solenoid valve 16, flows through the second expansion valve 24 and is throttled into a low-pressure two-phase refrigerant, evaporates in the first heat exchanger 4, and then enters the ejector 6. In the enthalpy-increasing heat exchanger 8, the two-phase refrigerant throttled by the enthalpy-increasing expansion valve 9 is heated into a superheated gas, mixed with the superheated gas at the outlet of the first compressor 1 and then enters the second compressor 2 for secondary compression.

[0087] In the refrigeration mode, the second expansion valve 24 is closed, the first expansion valve 22 and the enthalpy-increasing expansion valve 9 are opened, the first solenoid valve 15 and the third solenoid valve 17 are opened, and the second solenoid valve 16, the fourth solenoid valve 18, the fifth solenoid valve 19, the sixth solenoid valve 20, and the seventh solenoid valve 21 are closed.

[0088] The high-pressure gaseous refrigerant at the outlet of the second compressor 2 passes through the first solenoid valve 15, flows through the first heat exchanger 4 and is condensed into a liquid state, passes through the second one-way valve 25 and the third solenoid valve 17, and enters the enthalpy-increasing heat exchanger 8 for further subcooling. A part of the subcooled high-pressure liquid refrigerant is throttled into a low-pressure two-phase refrigerant by the first expansion valve 22, evaporates in the second heat exchanger 5, enters the gas-liquid separator 7, and the gaseous refrigerant returns to the first compressor 1 through the return air pipe. Another part of the subcooled liquid enters the enthalpy-increasing heat exchanger 8 and is heated into a superheated gas, which is mixed with the superheated gas at the outlet of the first compressor 1 and then enters the second compressor 2 for secondary compression.

[0089] It can be understood that according to the load demand, by opening or closing the sixth solenoid valve 20 and the seventh solenoid valve 21, the single-stage or two-stage compression mode of the system can be switched. Specifically, the displacement of the first compressor 1 is higher than that of the second compressor 2. When the load demand is high, the sixth solenoid valve 20 and the seventh solenoid valve 21 are closed; under medium load, the sixth solenoid valve 20 is open and the seventh solenoid valve 21 is closed; when the load is low, the sixth solenoid valve 20 is closed and the seventh solenoid valve 21 is open.

[0090] The control method, control device and heat pump system of the present invention will be described below with reference to the accompanying drawings. Among them, before describing the embodiments of the present invention in detail, the entire application scenario will be described first. The control method, control device, electronic device and computer-readable storage medium of the heat pump system in the embodiments of the present invention can be applied not only to the local heat pump system, but also to the cloud platform in the Internet field, or the cloud platform in other types of Internet fields, or can also be applied to third-party devices. Among them, the third-party devices may include various different types such as mobile phones, tablet computers, laptops, in-vehicle computers and other intelligent terminals.

[0091] Only the control method applicable to the heat pump system will be described below as an example. It should be understood that the control method of the embodiments of the present invention can also be applicable to the cloud platform and third-party devices.

[0092] As Figure 3 shown, the control method of the heat pump system according to the second aspect embodiment of the present invention includes: Step S1, receiving a working instruction for controlling the working mode of the heat pump system, and determining the to-be-operated mode of the heat pump system; Step S2, according to the to-be-operated mode, controlling and adjusting the opening degrees of each solenoid valve to control the heat pump system to enter the to-be-operated mode.

[0093] The control method of the heat pump system according to an embodiment of the present invention has the following specific working process: First, the system receives an instruction from an external control unit (such as a thermostat or a central controller), and this instruction contains the working mode information that the heat pump system should adopt, such as starting the heating mode, the cooling mode, or performing a mode switch, etc. This process reflects the system's ability to respond immediately to the external environment or user needs.

[0094] According to the received working instruction, the system software or controller will analyze and confirm the to-be-operated mode that the heat pump system is about to enter. Subsequently, the system automatically adjusts the opening and closing states of each solenoid valve. These solenoid valves are distributed at key nodes of the refrigerant cycle. Through their precise control, the system can smoothly switch between different modes or optimize the operating efficiency of the current mode. For example, in the heating mode, certain solenoid valves will open to guide the refrigerant to the enthalpy-increasing system or ensure the smooth progress of double-stage compression; while in the cooling mode, the opening and closing of the solenoid valves are adjusted to establish a refrigerant path suitable for the refrigeration cycle. This control mechanism ensures the precise matching of the refrigerant flow path to meet the best heat exchange efficiency and energy efficiency ratio in the current mode.

[0095] Through the above control method, the present invention not only improves the operating efficiency and response speed of the heat pump system, but also simplifies the operation process, reduces manual intervention, enables the system to more intelligently adapt to various working scenarios and external environment changes, and ensures that it can efficiently and stably provide the required cooling or heating services under any working conditions.

[0096] According to some embodiments of the present invention, the step of controlling and adjusting the opening degrees of each solenoid valve according to the to-be-operated mode to control the heat pump system to enter the to-be-operated mode specifically includes: When the to-be-operated mode is the heating mode, control the second solenoid valve 16, the fourth solenoid valve 18, and the fifth solenoid valve 19 to open, and control the first solenoid valve 15 and the third solenoid valve 17 to close; When the to-be-operated mode is the cooling mode, control the first solenoid valve 15 and the third solenoid valve 17 to open, and control the second solenoid valve 16 and the fourth solenoid valve 18 to close.

[0097] In this way, through the instant control of the solenoid valves, the system can quickly respond to changes in the external environment or user needs, seamlessly transition from the heating mode to the cooling mode or vice versa, improving the user experience. This rapid response ability is crucial for coping with changing climatic conditions. Moreover, the precise solenoid valve control strategy reduces unnecessary refrigerant bypass or circulation chaos, maintains the stability of the internal pressure and flow rate of the system, thereby extending the equipment life and reducing the maintenance cost.

[0098] According to some embodiments of the present invention, the control method further includes: Obtain the load demand of the heat pump system; According to the load demand, control and adjust the opening degrees of the sixth solenoid valve 20 and the seventh solenoid valve 21 to switch between single-stage and two-stage compression modes.

[0099] Furthermore, if the displacement of the first compressor 1 is higher than that of the second compressor 2, then when the load demand is within the first load range, control the sixth solenoid valve 20 to close and the seventh solenoid valve 21 to open; when the load demand is within the second load range, control the sixth solenoid valve 20 to open and the seventh solenoid valve 21 to close; when the load demand is within the third load range, control both the sixth solenoid valve 20 and the seventh solenoid valve 21 to close, where the first load range is less than the second load range, and the second load range is less than the third load range.

[0100] In summary, the system can adjust the compressor operating mode according to the real-time load demand. This means that at low loads (the first load range), only the second compressor 2 with a smaller displacement is used, saving energy; at medium loads (the second load range), the first compressor 1 is turned on and works together with the second compressor 2 to increase the system output; while at high loads (the third load range), both compressors are fully open to ensure sufficient cooling or heating capacity. This flexible adaptability improves the overall efficiency of the system and meets the performance requirements under different working conditions.

[0101] Specifically, by precisely matching the compressor operating state with the actual load, the low-efficiency operation of the large compressor at low loads is avoided, thus significantly improving the overall energy efficiency ratio of the system and reducing the operating cost.

[0102] At the same time, the intelligent adjustment of compressor use reduces unnecessary mechanical wear, especially the protection of the first compressor 1 with a large displacement, which helps to extend the service life of the heat pump system.

[0103] In addition, the real-time monitoring and rapid response mechanism of the load demand ensure that the system can quickly adapt to changes in internal and external conditions, provide continuous and stable heating and cooling services, and improve user comfort. Moreover, the automated control logic reduces the burden of manual intervention, makes system maintenance simpler, reduces the possibility of operation errors, and improves the reliability and usability of the system.

[0104] As Figure 4 shown, the control device of the heat pump system according to the third aspect embodiment of the present invention includes: An acquisition module 110, configured to receive a work instruction for controlling the operating mode of the heat pump system and determine the to-be-operated mode of the heat pump system; A control module 120, configured to control and adjust the opening degrees of each solenoid valve according to the to-be-operated mode to control the heat pump system to enter the to-be-operated mode.

[0105] Figure 5Illustrates a schematic diagram of the physical structure of an electronic device, as Figure 5 shown. The electronic device may include: a processor 810, a communications interface 820, a memory 830, and a communication bus 840. Among them, the processor 810, the communications interface 820, and the memory 830 communicate with each other through the communication bus 840. The processor 810 may call the logical instructions in the memory 830 to execute the control method of the heat pump system, including: receiving a work instruction for controlling the working mode of the heat pump system, and determining the to-be-operated mode of the heat pump system; according to the to-be-operated mode, controlling and adjusting the opening degrees of each solenoid valve to control the heat pump system to enter the to-be-operated mode.

[0106] In addition, when the logical instructions in the above-mentioned memory 830 are implemented in the form of software functional units and sold or used as an independent product, they may be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, may be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods in various embodiments of the present invention. The aforementioned storage medium includes: USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs, etc., which can store program codes.

[0107] On the other hand, the present invention also provides a computer program product. The computer program product 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 heat pump system provided by the above-mentioned various methods, including: receiving a work instruction for controlling the working mode of the heat pump system, and determining the to-be-operated mode of the heat pump system; according to the to-be-operated mode, controlling and adjusting the opening degrees of each solenoid valve to control the heat pump system to enter the to-be-operated mode.

[0108] On yet another aspect, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it is implemented to execute the control method of the heat pump system provided by the above-mentioned various methods, including: receiving a work instruction for controlling the working mode of the heat pump system, and determining the to-be-operated mode of the heat pump system; according to the to-be-operated mode, controlling and adjusting the opening degrees of each solenoid valve to control the heat pump system to enter the to-be-operated mode.

[0109] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative work.

[0110] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment 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 such an understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods of each embodiment or some parts of the embodiments.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of each embodiment of the present invention.

Claims

1. A heat pump system, characterized in that, Comprising: A first compressor, a second compressor, a four-way valve, a second heat exchanger, an ejector, and a gas-liquid separator connected through a main refrigerant circuit, wherein the first compressor and the second compressor are connected in series, and the gas outlet of the gas-liquid separator communicates with the suction port of the first compressor; The outlet and the liquid inlet of the ejector communicate with the inlet of the gas-liquid separator and the second heat exchanger respectively, and the gas inlet of the ejector communicates with the gas outlet of the gas-liquid separator through an ejector branch, and a first heat exchanger is provided on the ejector branch.

2. The heat pump system according to claim 1, wherein, It further comprises an enthalpy-increasing device, the enthalpy-increasing device includes an enthalpy-increasing heat exchanger, an enthalpy-increasing expansion valve, and an enthalpy-increasing branch, both ends of the enthalpy-increasing branch communicate with the second heat exchanger and the suction port of the second compressor respectively, the enthalpy-increasing expansion valve is provided on the enthalpy-increasing branch, and the enthalpy-increasing branch flows through the enthalpy-increasing heat exchanger, and the enthalpy-increasing heat exchanger is located between the second heat exchanger and the liquid inlet of the ejector.

3. The heat pump system according to claim 2, characterized in that, The ejector branch communicates with the main refrigerant circuit through a first branch and a second branch respectively, a first solenoid valve is provided on the first branch, a second solenoid valve is provided on the ejector branch, and a third solenoid valve is provided on the second branch; And in the refrigeration mode, the first branch is located upstream of the inlet of the first heat exchanger, the second branch is located downstream of the outlet of the first heat exchanger, a fourth solenoid valve is provided on the main refrigerant circuit between the second branch and the liquid inlet of the ejector, and a fifth solenoid valve is provided on the main refrigerant circuit between the first branch and the outlet of the ejector.

4. The heat pump system according to claim 2, characterized in that, A first expansion valve is provided on the main refrigerant circuit, and a first check valve is connected in parallel with the first expansion valve; a second expansion valve is provided on the ejector branch, and a second check valve is connected in parallel with the second expansion valve.

5. The heat pump system according to any one of claims 1 to 4, characterized in that A seventh solenoid valve is connected in parallel at both ends of the first compressor, and a sixth solenoid valve is connected in parallel at both ends of the second compressor.

6. The heat pump system according to any one of claims 1 to 4, characterized in that, An intermediate heat exchanger is provided between the outlet of the gas-liquid separator and the suction port of the first compressor, and the main refrigerant circuit flows through the intermediate heat exchanger.

7. A control method for a heat pump system according to any one of claims 1 to 6, characterized in that, Comprising: Receiving a working instruction for controlling the working mode of the heat pump system, and determining the to-be-operated mode of the heat pump system; According to the to-be-operated mode, controlling and adjusting the opening degrees of each solenoid valve to control the heat pump system to enter the to-be-operated mode.

8. The control method of the heat pump system according to claim 7, characterized in that, The step of controlling and adjusting the opening degrees of each solenoid valve according to the to-be-operated mode to control the heat pump system to enter the to-be-operated mode specifically includes: when the to-be-operated mode is the heating mode, controlling the second solenoid valve, the fourth solenoid valve, and the fifth solenoid valve to open, and controlling the first solenoid valve and the third solenoid valve to close; When the to-be-operated mode is the refrigeration mode, controlling the first solenoid valve and the third solenoid valve to open, and controlling the second solenoid valve and the fourth solenoid valve to close.

9. The control method of the heat pump system according to claim 7, wherein It further comprises: Obtaining the load demand of the heat pump system; According to the load demand, controlling and adjusting the opening degrees of the sixth solenoid valve and the seventh solenoid valve to switch the single-stage and double-stage compression modes; Preferably, the displacement of the first compressor is higher than that of the second compressor. Then, when the load demand is in the first load range, the sixth solenoid valve is controlled to close and the seventh solenoid valve is controlled to open; when the load demand is in the second load range, the sixth solenoid valve is controlled to open and the seventh solenoid valve is controlled to close; when the load demand is in the third load range, both the sixth solenoid valve and the seventh solenoid valve are controlled to close, where the first load range is smaller than the second load range, and the second load range is smaller than the third load range.

10. A control device for a heat pump system according to any one of claims 1 to 6, characterized in that, Comprising: an acquisition module, configured to receive a working instruction for controlling the working mode of the heat pump system and determine the to-be-operated mode of the heat pump system; a control module, configured to control and adjust the opening degrees of the solenoid valves according to the to-be-operated mode, so as to control the heat pump system to enter the to-be-operated mode.

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