Heat pump system, heat pump unit and control method thereof

Abstract

The application discloses a heat pump system, a heat pump unit and a control method thereof. The heat pump system comprises a compressor, a vortex tube, a first indoor heat exchanger, a second indoor heat exchanger, an outdoor heat exchanger, a first gas-liquid separator and a first intermediate heat exchanger connected to form a refrigerant circulation loop. The inlet of the vortex tube is connected to the exhaust port of the compressor, the hot end of the vortex tube is connected to the first indoor heat exchanger for main heating, the cold end is connected to the second indoor heat exchanger to cool the refrigerant from the low-boiling-point fluid port of the first gas-liquid separator, and the refrigerant is sent into the compressor after subcooling through the first intermediate heat exchanger. The application utilizes the vortex tube to send the hot fluid into the first indoor heat exchanger for main heating, and the cold fluid into the second indoor heat exchanger to cool the low-boiling-point refrigerant purified through the gas-liquid separator to realize deep subcooling. The self-repeating cascade technology is utilized to make the high-boiling-point component and the low-boiling-point component work in the high-temperature heating area and the ultra-low-temperature evaporation area respectively, and the energy cascade utilization is realized through the multi-stage intermediate heat exchanger.

Description

Technical Field

[0001] This invention relates to the field of heat pump system technology, and in particular to a heat pump system with vortex tubes, a heat pump unit and its control method. Background Technology

[0002] With the acceleration of global industrialization and the improvement of people's living standards, the proportion of building energy consumption in the energy structure continues to rise. Developing high-efficiency, wide-temperature-range heat pump technology to achieve energy conservation and emission reduction has become an urgent need for the HVAC industry. Especially in extremely cold regions, where ambient temperatures can drop to -45℃ or even -50℃, traditional air-cooled heat pumps and ordinary low-temperature enthalpy-increasing units face severe challenges: the evaporation pressure of a single refrigerant is too low at extremely low temperatures, leading to a sharp drop in compressor volumetric efficiency, excessive pressure ratio, and uncontrolled exhaust temperature. The unit is highly susceptible to shutdown protection failures and unstable operation.

[0003] To address these challenges, the industry has attempted to introduce cascade heat pump technology. This technology utilizes the property differences between the high- and low-boiling-point components of a non-azeotropic refrigerant mixture to construct two independent heat exchange cycles: the high-boiling-point component handles the high-temperature heating cycle, while the low-boiling-point component handles the ultra-low-temperature evaporation cycle, thereby widening the system's operating temperature range. Simultaneously, to achieve efficient energy distribution, vortex tubes have begun to be applied to heat pump systems. Leveraging their lack of moving parts and ability to instantly split a high-pressure fluid into two streams of hot and cold fluid, they aim to improve heating performance.

[0004] However, existing technologies still have significant drawbacks in practical applications, resulting in limited performance at extremely low temperatures:

[0005] 1. The hot and cold flows generated by the vortex tube are not deeply integrated into the self-cascade system. The low temperature at the cold end is not used for the subcooling of low-boiling-point components, resulting in limited enthalpy increase and gas replenishment effect. The high temperature at the hot end is not accurately matched to the heating demand of high-boiling-point components, resulting in energy waste.

[0006] 2. Traditional enthalpy-increasing loops have insufficient enthalpy of the gas replenishment at extremely low temperatures, which cannot effectively reduce the exhaust temperature. Furthermore, the structural design of the intermediate heat exchanger is not optimized for the heat exchange requirements of high and low boiling point components, resulting in low overall system energy efficiency.

[0007] Therefore, how to design heat pump systems, heat pump units and their control methods that effectively improve energy utilization and optimize system energy efficiency are technical problems that the industry urgently needs to solve. Summary of the Invention

[0008] To address the shortcomings of existing technologies, such as low energy utilization and poor heating performance, this invention proposes a heat pump system, a heat pump unit, and its control method. The system utilizes a vortex tube to separate the high-pressure refrigerant into two streams: a hot stream enters the first indoor heat exchanger for primary heating, while the cold stream enters the second indoor heat exchanger to cool the low-boiling-point refrigerant purified by a component separator (enthalpy-increasing loop), achieving deep subcooling. Simultaneously, the system employs self-cascade technology, allowing the high- and low-boiling-point components to operate in the high-temperature heating zone and the ultra-low-temperature evaporation zone, respectively, and achieves tiered energy utilization through multi-stage intermediate heat exchangers.

[0009] The technical solution adopted in this invention is to design a heat pump system with a vortex tube, including: a compressor, a vortex tube, a first indoor heat exchanger, a second indoor heat exchanger, an outdoor heat exchanger, a first gas-liquid separator, and a first intermediate heat exchanger connected to form a refrigerant circulation loop.

[0010] The inlet of the vortex tube is connected to the exhaust port of the compressor. The hot end outlet of the vortex tube is connected to the first end of the first indoor heat exchanger in the heating state. The cold end outlet of the vortex tube is connected to the first end of the second indoor heat exchanger.

[0011] The first gas-liquid separator is provided with a high-boiling-point fluid port, a low-boiling-point fluid port and a main end, and the first intermediate heat exchanger has a first main pipeline and a first secondary pipeline for mutual heat exchange.

[0012] The inlet of the first gas-liquid separator is connected to the second end of the first indoor heat exchanger, the high boiling point fluid port is connected to the suction side of the compressor, the low boiling point fluid port is connected to the first end of the first main pipeline, the second end of the first main pipeline is connected in series with the main throttling device to the first end of the outdoor heat exchanger, and the second end of the outdoor heat exchanger is connected to the suction side of the compressor in the heating state.

[0013] The second end of the second indoor heat exchanger is connected in series with the first throttling device and then connected to the first end of the first auxiliary pipeline. The second end of the first auxiliary pipeline is connected to the enthalpy-increasing port of the compressor.

[0014] This design uses a vortex tube to connect the hot end to the first indoor heat exchanger for main heating, and the cold end to the second indoor heat exchanger to cool the refrigerant from the low-boiling-point fluid port of the first gas-liquid separator. After being subcooled by the first intermediate heat exchanger, the refrigerant is sent to the compressor's enthalpy-increasing port. The dual flow of hot and cold air from the vortex tube enables cascaded energy utilization. The hot flow ensures high-temperature heating needs, while the cold flow deeply subcools the low-boiling-point components. This effectively solves the problem of excessively low evaporation pressure and excessively high pressure ratio of a single refrigerant at extremely low temperatures, and significantly expands the system's low-temperature operating range.

[0015] Furthermore, the heat pump system also includes: a regenerative gas-liquid separator, which has an inlet, an outlet, and a regenerative heat exchange pipeline passing through its inner cavity; the outlet of the regenerative gas-liquid separator is connected to the suction port of the compressor, the high-boiling-point fluid port is connected in series with the regenerative heat exchange pipeline to the inlet of the regenerative gas-liquid separator, and the outdoor heat exchanger is connected to the inlet of the regenerative gas-liquid separator in the heating state.

[0016] This design adds a regenerative gas-liquid separator to the heat pump system. The separator integrates a regenerative heat exchange pipeline. After the high-boiling-point fluid flows through the pipeline and exchanges heat, it enters the separator and mixes with the low-pressure fluid returning from the outdoor heat exchanger before being drawn into the compressor. This integrates gas-liquid separation and regenerative functions, preventing liquid refrigerant from directly entering the compressor and causing liquid slugging. It also utilizes the high-temperature return gas to preheat the liquid refrigerant before throttling, significantly improving the system's return gas superheat and overall energy efficiency.

[0017] Furthermore, the heat pump system also includes: a second intermediate heat exchanger, which has a second main pipeline and a second auxiliary pipeline for mutual heat exchange; the second main pipeline is connected in series between the second end of the first main pipeline and the main throttling device, and the high boiling point fluid port is connected in series with the regenerative heat exchange pipeline, the second throttling device and the second auxiliary pipeline to the inlet of the regenerative gas-liquid separator.

[0018] This design introduces a second intermediate heat exchanger, with its second main pipeline connected in series between the first intermediate heat exchanger and the main throttling device, and the second auxiliary pipeline connected in series between the high-boiling-point fluid port and the regenerative gas-liquid separator. The high-boiling-point fluid is used to further cool the main fluid refrigerant, while the main fluid refrigerant is used to cool the high-boiling-point fluid, realizing the cascade recovery and utilization of energy, and significantly improving the heat exchange efficiency and system heating capacity.

[0019] Furthermore, the heat pump system also includes: a four-way valve, the first end of which is connected to the hot end outlet of the vortex tube, the second end of which is connected to the first end of the first indoor heat exchanger, the third end of which is connected to the second end of the outdoor heat exchanger, and the fourth end of which is connected to the inlet of the regenerative gas-liquid separator.

[0020] This design adds a four-way valve to connect the hot end of the vortex tube, the first indoor heat exchanger, the outdoor heat exchanger, and the regenerative gas-liquid separator; by switching the flow direction through the four-way valve, the system is given the ability to freely switch between heating and defrosting modes, and reverse circulation can be achieved without modifying the pipeline, meeting the dual needs of continuous heating and automatic defrosting in cold regions.

[0021] Furthermore, the high-boiling-point fluid port is equipped with a control valve for switching its on / off state.

[0022] This design adds a control valve to the high-boiling-point fluid port, enabling active control of the flow direction of high-boiling-point components. Under defrosting or specific operating conditions, it can cut off the flow of high-boiling-point fluid to the outdoor heat exchanger, avoiding ineffective energy consumption. At the same time, it optimizes the flow distribution in different system modes, improving the flexibility and accuracy of operation control.

[0023] In some embodiments, the heat pump system can operate in a heating state; in the heating state, the first and second ends of the four-way valve are connected, the third and fourth ends are connected, and the first throttling device, the second throttling device, and the control valve all operate normally.

[0024] This design provides the operating logic for the heating state, which uses a four-way valve to connect the hot end outlet of the vortex tube to the first indoor heat exchanger, the outdoor heat exchanger to the regenerating gas-liquid separator, and maintains the normal operation of each throttling device and control valve; it establishes a complete flow path for the heating cycle, ensuring that the system can operate stably at extremely low temperatures according to the self-cascade and jet enthalpy increase path, thus guaranteeing heating performance and reliability.

[0025] In some embodiments, the heat pump system can operate in a defrost state; in the defrost state, the first and third ends of the four-way valve are connected, the second and fourth ends are connected, and the first throttling device, the second throttling device, and the control valve are all in a closed state.

[0026] This design provides the operating logic for the defrosting state. The path from the hot end outlet of the vortex tube to the outdoor heat exchanger and from the first indoor heat exchanger to the regenerating gas-liquid separator is opened through the four-way valve, while closing all throttling devices and control valves. A complete flow path for the defrosting cycle is established, and the high-temperature exhaust gas is used to defrost directly. At the same time, the enthalpy increase and subcooling circuits are cut off to achieve fast and efficient defrosting and minimize the indoor temperature drop.

[0027] Furthermore, the hot end outlet and / or cold end outlet of the vortex tube are equipped with regulating valves.

[0028] This design adds regulating valves to the hot and / or cold end outlets of the vortex tube, enabling stepless and precise control of the flow rates of hot and cold fluids. By dynamically adjusting the ratio of hot and cold flow, the matching relationship between heating capacity and subcooling can be optimized in real time according to the indoor load, further improving the system's energy efficiency ratio and partial load performance.

[0029] The present invention also proposes a heat pump unit that employs the aforementioned heat pump system.

[0030] This design applies a heat pump system to a heat pump unit, providing an integrated solution for cold regions with ultra-low temperature heating, high energy efficiency, and high reliability, significantly improving the unit's ability to operate in harsh environments.

[0031] This invention also proposes a control method for a heat pump system, which is applied to the aforementioned heat pump system and includes:

[0032] In heating mode, select either the first indoor heat exchanger or the second indoor heat exchanger as the target indoor heat exchanger.

[0033] Obtain the actual indoor temperature of the target indoor heat exchanger;

[0034] Compare the actual indoor temperature with its corresponding preset temperature range;

[0035] The corresponding outlet flow rate of the vortex tube is controlled based on the comparison results.

[0036] This design establishes a vortex tube flow adaptive control mechanism based on room temperature feedback, enabling the system to automatically respond to load changes and avoid energy waste while ensuring comfort.

[0037] Furthermore, controlling the corresponding outlet flow rate of the vortex tube based on the comparison results includes:

[0038] When the lower limit of the preset temperature range is less than the actual indoor temperature and less than the upper limit of the preset temperature range, the current operating state of the vortex tube is maintained.

[0039] When the actual indoor temperature is less than or equal to the lower limit of the preset temperature range, increase the hot end outlet flow rate of the vortex tube and / or decrease the cold end outlet flow rate of the vortex tube.

[0040] When the actual indoor temperature is greater than the upper limit of the preset temperature range, reduce the hot end outlet flow rate of the vortex tube and / or increase the cold end outlet flow rate of the vortex tube.

[0041] This design provides a refined flow control logic: when the room temperature is below the lower limit, the hot-end flow rate is increased to enhance heating; when it is above the upper limit, the hot-end flow rate is decreased to weaken heating. This strategy provides an intuitive and efficient temperature control method, achieving precise adjustment and stable operation of the system's heating capacity by quickly correcting room temperature deviations.

[0042] Furthermore, control methods also include:

[0043] When the actual indoor temperature is less than or equal to the lower limit of the preset temperature range, determine whether the hot end outlet flow rate of the vortex tube has risen to the preset upper limit flow rate. If not, increase the hot end outlet flow rate of the vortex tube and / or decrease the cold end outlet flow rate of the vortex tube. If so, increase the compressor operating frequency.

[0044] When the actual indoor temperature is greater than the upper limit of the preset temperature range, determine whether the hot end outlet flow rate of the vortex tube has dropped to the preset lower limit flow rate. If not, reduce the hot end outlet flow rate of the vortex tube and / or increase the cold end outlet flow rate of the vortex tube. If so, reduce the compressor operating frequency.

[0045] This design incorporates flow limit judgment logic. When the flow rate adjustment of the vortex tube reaches the upper or lower limit and still cannot meet the temperature control requirements, it automatically intervenes to adjust the compressor frequency. This solution achieves coordinated control with "flow rate adjustment as the main method and frequency adjustment as the auxiliary method". It prioritizes the rapid response of the vortex tube and adjusts the compressor load when necessary. This ensures both adjustment sensitivity and avoids frequent and large load changes of the compressor, thereby extending equipment life and optimizing energy efficiency.

[0046] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0047] 1. By introducing a vortex tube to separate the high-pressure refrigerant into two independent streams of hot and cold fluids, and in conjunction with the first gas-liquid separator and the first intermediate heat exchanger, the hot end fluid can be directly used for high-temperature heating, while the cold end fluid is used for subcooling low-boiling-point components and assisting in enthalpy increase. This completely solves the problems of excessively low evaporation pressure, excessively high pressure ratio and runaway exhaust temperature of a single refrigerant in extremely low-temperature environments, significantly widens the operating temperature range of the heat pump, and achieves stable and efficient heating at ultra-low temperatures.

[0048] 2. By setting up a regenerative gas-liquid separator with a regenerative heat exchange pipeline, the dual functions of gas-liquid separation and energy recovery are realized. On the one hand, it effectively prevents the risk of compressor liquid slugging caused by liquid refrigerant backflow. On the other hand, by using low-temperature return gas to pre-cool the liquid refrigerant before throttling, the subcooling degree of the system is greatly improved.

[0049] 3. By adding a second intermediate heat exchanger to construct a cascade subcooling architecture, the high-boiling-point components are used to further cool the main fluid refrigerant, while the high-boiling-point fluid itself is pre-cooled. This cascade energy utilization design greatly improves the heat exchange efficiency and solves the problem of heat capacity reduction caused by insufficient heat exchange in traditional self-cascade systems, thus significantly improving the heating efficiency ratio of the system at extremely low temperatures.

[0050] 4. By installing regulating valves at the hot and cold ends of the vortex tube, stepless and precise control of the flow rate of hot and cold fluids is achieved. This enables the system to dynamically optimize the matching relationship between heating capacity and subcooling capacity according to the indoor load, solving the problems of lag in regulation and low energy efficiency under partial load in traditional systems, and further tapping the energy-saving potential of the system. Attached Figure Description

[0051] The present invention will now be described in detail with reference to the embodiments and accompanying drawings, wherein:

[0052] Figure 1 This is a schematic diagram of the heat pump system of the present invention in heating mode;

[0053] Figure 2 This is a schematic diagram of the defrosting connection of the heat pump system of the present invention;

[0054] Figure 3 This is a schematic diagram of the port of the vortex tube of the present invention;

[0055] Figure 4 This is a schematic diagram of the ports of the first intermediate heat exchanger of the present invention;

[0056] Figure 5 This is a schematic diagram of the ports of the first gas-liquid separator of the present invention;

[0057] Figure 6 This is a schematic diagram of the port of the regenerative gas-liquid separator of the present invention;

[0058] Figure 7 This is a schematic diagram of the ports of the second intermediate heat exchanger of the present invention;

[0059] Figure 8 This is a schematic diagram of the ports of the four-way valve of the present invention;

[0060] Figure 9 This is a schematic diagram of the refrigerant flow direction in the heating state of the heat pump system of the present invention;

[0061] Figure 10 This is a schematic diagram of the refrigerant flow direction in the defrosting state of the heat pump system of the present invention;

[0062] Figure 11 This is a flowchart illustrating the control method of the present invention;

[0063] Figure 12 This is a schematic diagram of the flow rate regulation of the vortex tube of the present invention;

[0064] Figure 13 This is a schematic diagram of the combined adjustment of the vortex tube and the compressor of the present invention;

[0065] Figure 14 These are schematic diagrams of the control flow for some application examples of the present invention;

[0066] Explanation of reference numerals in the attached figures:

[0067] 1. Compressor;

[0068] 2. Vortex tube; 2a. Inlet; 2b. Hot end outlet; 2c. Cold end outlet;

[0069] 3. Four-way valve; 3d, first end; 3a, second end; 3c, third end; 3b, fourth end;

[0070] 4. First indoor heat exchanger;

[0071] 5. Second indoor heat exchanger;

[0072] 6. First gas-liquid separator; 6a. Main end; 6b. High-boiling-point fluid port; 6c. Low-boiling-point fluid port;

[0073] 7. First throttling device;

[0074] 8. First intermediate heat exchanger; 8b. First end of the first main pipeline; 8a. Second end of the first main pipeline; 8c. First end of the first auxiliary pipeline; 8d. Second end of the first auxiliary pipeline;

[0075] 9. Second throttling device;

[0076] 10. Second intermediate heat exchanger; 10b. First end of second auxiliary pipeline; 10a. Second end of second auxiliary pipeline; 10c. First end of second main pipeline; 10d. Second end of second main pipeline;

[0077] 11. Regenerative gas-liquid separator; 11a. Outlet; 11b. Inlet; 11c. First end of regenerative heat exchange pipeline; 11d. Second end of regenerative heat exchange pipeline;

[0078] 12. Main throttling device;

[0079] 13. Outdoor heat exchanger;

[0080] 14. Control valve. Detailed Implementation

[0081] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0082] This invention proposes a heat pump system, more specifically a jet-induced enthalpy-enhancing self-cascade heat pump system with vortex tubes. Its core lies in the deep integration of the hot and cold currents generated by the vortex tubes with the self-cascade heat pump system, solving the heating problem under extremely low temperature conditions. For example... Figures 1 to 2 As shown, the system includes: compressor 1, vortex tube 2, first indoor heat exchanger 4, second indoor heat exchanger 5, outdoor heat exchanger 13, first gas-liquid separator 6, and first intermediate heat exchanger 8. These components are connected via refrigerant piping to form a refrigerant circulation loop. Compressor 1 is an enthalpy-increasing compressor, and its exhaust port is connected to the inlet 2a of vortex tube 2, delivering high-temperature, high-pressure gaseous refrigerant to vortex tube 2.

[0083] like Figure 3 As shown, the vortex tube 2 serves as the core of the system's energy distribution. Its hot-end outlet 2b is connected to the first end of the first indoor heat exchanger 4 in heating mode, used to output high-temperature heat flow for primary heating; its cold-end outlet 2c is connected to the first end of the second indoor heat exchanger 5, used to output low-temperature cold flow for auxiliary heat exchange. This hot-cold separation design fundamentally changes the traditional single heat source output mode of heat pumps, providing a physical basis for subsequent self-cascade and enthalpy enhancement.

[0084] like Figure 4As shown, the first gas-liquid separator 6 is configured to separate a non-azeotropic refrigerant mixture into a high-boiling-point component and a low-boiling-point component, and is respectively provided with a high-boiling-point fluid port 6b, a low-boiling-point fluid port 6c, and a general end 6a for fluid inlet and outlet. Figure 5 As shown, the first intermediate heat exchanger 8 has a first main pipeline and a first auxiliary pipeline for mutual heat exchange. The second end of the first indoor heat exchanger 4 is connected to the main end 6a of the first gas-liquid separator 6, allowing the refrigerant after heating to flow into the first gas-liquid separator 6 for component separation. The high-boiling-point fluid port 6b is connected to the suction side of the compressor 1, ensuring that the high-boiling-point component flows back directly; the low-boiling-point fluid port 6c is connected to the first end 8b of the first main pipeline, allowing the low-boiling-point component to enter the first intermediate heat exchanger 8 for cooling. The second end 8a of the first main pipeline is connected in series with the main throttling device 12 (such as an electronic expansion valve) and then connected to the first end of the outdoor heat exchanger 13. The second end of the outdoor heat exchanger 13 is connected to the suction side of the compressor 1 in the heating state. The second end of the second indoor heat exchanger 5 is connected in series with the first throttling device 7 (such as an electronic expansion valve) and then connected to the first end 8c of the first auxiliary pipeline. The second end 8d of the first auxiliary pipeline is connected to the enthalpy-increasing port of the compressor 1.

[0085] Through the above structure, in the heating cycle, the high-temperature, high-pressure gaseous refrigerant is divided into two streams, hot and cold, via the vortex tube 2. The hot stream enters the first indoor heat exchanger 4 to release heat and heat the indoor space; the cold stream enters the second indoor heat exchanger 5 to release cooling energy, used to cool the refrigerant from the low-boiling-point fluid port 6c of the first gas-liquid separator 6. After being deeply subcooled in the first intermediate heat exchanger 8, the low-boiling-point refrigerant is throttled by the main throttling device 12 and enters the outdoor heat exchanger 13 to evaporate and absorb heat. This efficient utilization of hot and cold energy effectively solves the problems of excessively low evaporation pressure, excessively high pressure ratio, and runaway exhaust temperature of a single refrigerant in extremely low-temperature environments, significantly widening the system's low-temperature operating range. At the same time, the subcooling of the low-boiling-point component by the cold stream of the vortex tube 2 enhances the vapor injection enthalpy increase effect, thereby improving the system's heating capacity and energy efficiency.

[0086] Based on the above core architecture, in some embodiments of the present invention, the heat pump system further includes: a regenerative gas-liquid separator 11.

[0087] like Figure 6 As shown, the regenerative gas-liquid separator 11 is provided with an inlet 11b, an outlet 11a, and a regenerative heat exchange pipeline passing through its inner cavity; the outlet 11a of the regenerative gas-liquid separator 11 is connected to the suction port of the compressor 1, the high boiling point fluid port 6b is connected in series with the regenerative heat exchange pipeline to the inlet 11b of the regenerative gas-liquid separator 11, and the outdoor heat exchanger 13 is connected to the inlet 11b of the regenerative gas-liquid separator 11 in the heating state.

[0088] This design integrates gas-liquid separation and regeneration functions by adding a regenerating gas-liquid separator 11 to the heat pump system. When the high-boiling-point fluid flows through the regenerating heat exchange pipeline, it exchanges heat with the low-pressure, high-temperature refrigerant from the outdoor heat exchanger 13 and the intermediate heat exchanger 10. On the one hand, this prevents the liquid refrigerant from directly entering the compressor 1 and causing liquid slugging, thus improving system safety. On the other hand, by using the low-temperature return gas to pre-cool the liquid refrigerant before throttling, the subcooling degree of the system is significantly improved.

[0089] Based on this, in some embodiments of the present invention, the heat pump system is further provided with a second intermediate heat exchanger 10.

[0090] like Figure 7 As shown, the second intermediate heat exchanger 10 has a second main pipeline and a second auxiliary pipeline for mutual heat exchange. The second main pipeline is connected in series between the second end 8a of the first main pipeline and the main throttling device 12. The high-boiling-point fluid port 6b is connected in series with the regenerative heat exchange pipeline, the second throttling device 9 (such as an electronic expansion valve), and the second auxiliary pipeline, and then connected to the inlet of the regenerative gas-liquid separator 11. This design utilizes the high-boiling-point fluid to further cool the main fluid refrigerant, while simultaneously utilizing the main fluid refrigerant to cool the high-boiling-point fluid, thus achieving cascaded energy recovery and utilization.

[0091] Specifically, the low-boiling-point refrigerant from the first intermediate heat exchanger 8 is subcooled again in the second intermediate heat exchanger 10, increasing the heating capacity per unit mass of refrigerant; while the high-boiling-point refrigerant from the first gas-liquid separator 6 is precooled in the regenerating gas-liquid separator 11, reducing flash gas after throttling and improving evaporation efficiency. This multi-stage subcooling design significantly improves heat exchange efficiency and system heating capacity, further enhancing heating performance at extremely low temperatures.

[0092] like Figure 1 and Figure 8 As shown, in a preferred embodiment of the present invention, the heat pump system further includes: a four-way valve 3, the first end 3d of the four-way valve 3 being connected to the hot end outlet 2b of the vortex tube 2, the second end 3a being connected to the first end of the first indoor heat exchanger 4, the third end 3c being connected to the second end of the outdoor heat exchanger 13, and the fourth end 3b being connected to the inlet 11b of the regenerating gas-liquid separator 11.

[0093] This design adds a four-way valve 3 to connect the hot end outlet 2b of the vortex tube 2, the first indoor heat exchanger 4, the outdoor heat exchanger 13, and the regenerative gas-liquid separator 11. By switching the flow direction through the four-way valve 3, the system can freely switch between heating mode and defrosting mode, and can achieve reverse circulation without modifying the pipeline, thus meeting the dual needs of continuous heating and automatic defrosting in cold regions.

[0094] To better adapt to the system's operational requirements in different modes, the high-boiling-point fluid port 6b is equipped with a control valve 14 for switching its on / off state. The control valve 14 enables active control of the flow direction of the high-boiling-point component; under defrosting or specific operating conditions, it can cut off the flow of the high-boiling-point fluid to the outdoor heat exchanger 13, avoiding ineffective energy consumption, while optimizing the flow distribution in different system modes, thus improving the flexibility and accuracy of operation control.

[0095] Based on the system architecture of the preferred embodiment, the heat pump system can operate in the heating state; in the heating state, the first end 3d and the second end 3a of the four-way valve 3 are connected, the third end 3c and the fourth end 3b are connected, and the first throttling device 7, the second throttling device 9 and the control valve 14 are all normally switched on and off.

[0096] Specifically, such as Figure 9 As shown, in the heating state, the high-temperature and high-pressure gaseous refrigerant passes through the compressor 1 and enters the inlet 2a of the vortex tube 2, where it splits the fluid into two.

[0097] A stream of fluid with a lower temperature enters the second indoor heat exchanger 5 through the cold end outlet 2c of the vortex tube 2 for heat exchange. After heat exchange, the fluid is throttled and depressurized by the first throttling device 7, becoming a low-temperature and low-pressure fluid. It then enters the first end 8c of the first auxiliary pipe of the first intermediate heat exchanger 8 to cool the low-boiling-point refrigerant fluid from the first gas-liquid separator 6. After heat exchange, it flows out from the second end 8d of the first auxiliary pipe of the first intermediate heat exchanger 8 and enters the enthalpy-increasing port of the compressor 1 to complete the cycle.

[0098] A stream of fluid with a higher temperature enters the first end 3d of the four-way valve 3 through the hot end outlet 2b of the vortex tube 2. After flowing out from the second end 3a of the four-way valve 3, it enters the first indoor heat exchanger 4 for heat exchange. The fluid after heat exchange enters the main end 6a of the first gas-liquid separator 6. The mixed refrigerant is divided into two in the first gas-liquid separator 6.

[0099] A refrigerant fluid with a high boiling point flows out from the high boiling point fluid port 6b of the first gas-liquid separator 6, enters the first end 11c of the regenerating heat exchange pipeline of the regenerating gas-liquid separator 11 through the control valve 14, and becomes a higher temperature fluid after heat exchange. It flows out from the second end 11d of the regenerating heat exchange pipeline of the regenerating gas-liquid separator 11, and becomes a low temperature and low pressure fluid after being throttled and depressurized by the second throttling device 9. It enters the first end 10b of the second auxiliary pipeline of the second intermediate heat exchanger 10 to further cool the fluid from the first intermediate heat exchanger 8. After heat exchange, it flows out from the second end 10a of the second auxiliary pipeline of the second intermediate heat exchanger 10 and enters the inlet 11b of the regenerating gas-liquid separator 11.

[0100] A refrigerant fluid with a low boiling point flows out from the low boiling point fluid port 6c of the first gas-liquid separator 6 and enters the first end 8b of the first main pipe of the first intermediate heat exchanger 8. After being cooled down, the refrigerant fluid flows out from the second end 8a of the first main pipe of the first intermediate heat exchanger 8 and enters the first end 10c of the second main pipe of the second intermediate heat exchanger 10. After being cooled down again, the refrigerant fluid flows out from the second end 10d of the second main pipe of the second intermediate heat exchanger 10. After being throttled and depressurized by the main throttling device 12 to become a low-temperature and low-pressure refrigerant, it enters the outdoor heat exchanger 13 for evaporation and heat absorption, and becomes a low-pressure and high-temperature refrigerant fluid. After flowing out of the outdoor heat exchanger 13, it flows through the third end 3c and the fourth end 3b of the four-way valve 3 and enters the inlet 11b of the regenerating gas-liquid separator 11.

[0101] The low-pressure, high-temperature refrigerant from the second intermediate heat exchanger 10 and the low-pressure, high-temperature refrigerant from the outdoor heat exchanger 13 are combined at the inlet 11b of the regenerating gas-liquid separator 11 and then enter the regenerating gas-liquid separator 11 together. After mixing in the regenerating gas-liquid separator 11, the refrigerant flows out from the outlet 11a of the regenerating gas-liquid separator 11 and enters the suction port of the compressor 1, completing the entire cycle.

[0102] This design provides the operating logic for the heating state. The four-way valve 3 connects the hot end outlet 2b of the vortex tube 2 to the first indoor heat exchanger 4, the outdoor heat exchanger 13 to the regenerating gas-liquid separator 11, and maintains the normal operation of each throttling device and control valve 14. It establishes a complete flow path for the heating cycle, ensuring that the system can operate stably at extremely low temperatures according to the self-cascade and jet enthalpy increase path, thus guaranteeing heating performance and reliability.

[0103] Based on the system architecture of the preferred embodiment, the heat pump system can operate in a defrost state; in the defrost state, the first end 3d and the third end 3c of the four-way valve 3 are connected, the second end 3a and the fourth end 3b are connected, and the first throttling device 7, the second throttling device 9 and the control valve 14 are all in a closed state.

[0104] Specifically, such as Figure 10 As shown, in the defrosting state, the high-temperature and high-pressure gaseous refrigerant passes through the compressor 1, enters the inlet 2a of the vortex tube 2, flows out from the hot end outlet 2b of the vortex tube 2, enters the four-way valve 3, flows through the first end 3d of the four-way valve 3, flows out from the third end 3c, and enters the outdoor heat exchanger 13 for defrosting.

[0105] After flowing out of the outdoor heat exchanger 13, it passes through the main throttling device 12 and enters the second end 10d of the second main pipe of the second intermediate heat exchanger 10. It then flows out from the first end 10c of the second main pipe and enters the second end 8a of the first main pipe of the first intermediate heat exchanger 8. After flowing out from the first end 8b of the first main pipe, it enters the low-boiling-point fluid port 6c of the first gas-liquid separator 6 and then flows out from the main end 6a of the first gas-liquid separator 6 and enters the first indoor heat exchanger 4 for heat exchange. After flowing out from the first indoor heat exchanger 4, it flows through the second end 3a of the four-way valve 3 and then from the fourth end 3b. After flowing out from the inlet 11b of the regenerating gas-liquid separator 11, it flows out from the outlet 11a and enters the suction port of the compressor 1, completing the entire cycle.

[0106] This design provides the operating logic for the defrosting state. The path from the hot end outlet 2b of the vortex tube 2 to the outdoor heat exchanger 13 and from the first indoor heat exchanger 4 to the regenerating gas-liquid separator 11 is opened through the four-way valve 3, while closing each throttling device and control valve 14. A complete flow path for the defrosting cycle is established, and the high-temperature exhaust gas is used to defrost directly. At the same time, the enthalpy increase and subcooling circuits are cut off to achieve fast and efficient defrosting and minimize the indoor temperature drop.

[0107] To achieve precise control of the flow rates of hot and cold fluids, the hot-end outlet 2b and / or cold-end outlet 2c of the vortex tube 2 are equipped with regulating valves. By dynamically adjusting the ratio of hot and cold flow, the matching relationship between heating capacity and subcooling can be optimized in real time according to the indoor load. For example, when the indoor temperature is low, the hot-end flow rate is increased and the cold-end flow rate is decreased to enhance heating; when the indoor temperature is high, the hot-end flow rate is decreased and the cold-end flow rate is increased to weaken heating. This refined energy management further taps into the energy-saving potential of the system and improves the energy efficiency ratio under partial load.

[0108] In a preferred embodiment of the invention, the heat pump system, through its unique "three-stage subcooling" architecture, greatly unlocks its heating potential under extreme conditions. Specifically, the first stage of subcooling is achieved through the first intermediate heat exchanger 8, which pre-cools the refrigerant fluid about to enter the intermediate heat exchanger 10, laying the foundation for deep subcooling. Building upon this, the second stage of subcooling is undertaken by the regenerative gas-liquid separator 11, specifically targeting the refrigerant fluid flowing through the second throttling device 9 for regenerative subcooling, effectively recovering the system's waste heat. Finally, the third stage of subcooling is completed through the second intermediate heat exchanger 10, ensuring that the refrigerant fluid entering the main throttling device 12 receives the lowest possible pre-evaporation temperature. This tiered cooling design significantly improves the system's unit heating capacity and energy efficiency ratio.

[0109] It should be noted that the heat exchangers and vortex tubes 2 mentioned in this article can be selected according to the actual application scenario. For example, the outdoor heat exchanger 13 is preferably a finned tube heat exchanger to adapt to extremely cold environments; the first indoor heat exchanger 4 and the second indoor heat exchanger 5 can flexibly choose finned tube, shell-and-tube, or plate heat exchangers to meet diverse installation and heat exchange requirements; and the first intermediate heat exchanger 8 and the second intermediate heat exchanger 10, which are the core of the system, also support efficient heat exchange types such as shell-and-tube or plate heat exchangers to ensure maximum heat exchange efficiency.

[0110] For example, the preferred vortex tube 2 is an electrically driven vortex tube, which has a simple structure and low cost. It can divide the fluid into two streams, one hot and one cold—the hot fluid has a higher temperature than the inlet, and the cold fluid has a lower temperature than the inlet. In this system, the application of the vortex tube achieves precise temperature zone division: its hot end ensures that the first indoor heat exchanger 4 can obtain a higher water or air temperature to meet the main heating requirements; its cold end enables the second indoor heat exchanger 5 to obtain a higher water or air temperature, which can assist in heating while also meeting the requirements for enthalpy increase and subcooling.

[0111] Generally, jet enthalpy-enhancing heat pumps are typically suitable for operating conditions from -15°C to -25°C, while cascade heat pumps are typically suitable for temperature ranges from -30°C to -40°C and below. This invention, by configuring components such as vortex tubes 2 and intermediate heat exchangers, deeply integrates the above two technologies, enabling the heat pump system to break through conventional limitations, further broaden the low-temperature application field, and extend stable and reliable heating services to extremely cold regions such as Northeast China.

[0112] The present invention also proposes a heat pump unit that uses the above-mentioned heat pump system to provide an integrated solution for cold regions with ultra-low temperature heating, high energy efficiency and high reliability, significantly improving the unit's operating capability in harsh environments.

[0113] like Figure 11 As shown, the present invention also proposes a control method for a heat pump system, which is applied to the aforementioned heat pump system and includes:

[0114] In heating mode, select either the first indoor heat exchanger 4 or the second indoor heat exchanger 5 as the target indoor heat exchanger.

[0115] Obtain the actual indoor temperature of the target indoor heat exchanger;

[0116] Compare the actual indoor temperature with its corresponding preset temperature range;

[0117] The corresponding outlet flow rate of vortex tube 2 is controlled based on the comparison results.

[0118] This design establishes a vortex tube flow adaptive control mechanism based on room temperature feedback, enabling the system to automatically respond to load changes and avoid energy waste while ensuring comfort.

[0119] like Figure 12 As shown, in some embodiments of the present invention, controlling the corresponding outlet flow rate of the vortex tube based on the comparison result includes:

[0120] When the lower limit of the preset temperature range is less than the actual indoor temperature and less than the upper limit of the preset temperature range, the current operating state of the vortex tube is maintained.

[0121] When the actual indoor temperature is less than or equal to the lower limit of the preset temperature range, increase the hot end outlet flow rate of the vortex tube 2 and / or decrease the cold end outlet flow rate of the vortex tube 2.

[0122] When the actual indoor temperature is greater than the upper limit of the preset temperature range, reduce the hot end outlet flow rate of the vortex tube 2 and / or increase the cold end outlet flow rate of the vortex tube 2.

[0123] This design provides a refined flow control logic: when the room temperature is below the lower limit, the hot-end flow rate is increased to enhance heating; when it is above the upper limit, the hot-end flow rate is decreased to weaken heating. This strategy provides an intuitive and efficient temperature control method, achieving precise adjustment and stable operation of the system's heating capacity by quickly correcting room temperature deviations.

[0124] like Figure 13 As shown, in a preferred embodiment of the present invention, the control method further includes:

[0125] When the actual indoor temperature is less than or equal to the lower limit of the preset temperature range, determine whether the hot end outlet flow rate of the vortex tube 2 has risen to the preset upper limit flow rate. If not, increase the hot end outlet flow rate of the vortex tube and / or decrease the cold end outlet flow rate of the vortex tube. If so, increase the compressor operating frequency.

[0126] When the actual indoor temperature is greater than the upper limit of the preset temperature range, determine whether the hot end outlet flow rate of the vortex tube 2 has dropped to the preset lower limit flow rate. If not, reduce the hot end outlet flow rate of the vortex tube and / or increase the cold end outlet flow rate of the vortex tube. If so, reduce the compressor operating frequency.

[0127] This design incorporates flow limit judgment logic. When the flow rate adjustment of the vortex tube reaches the upper or lower limit and still cannot meet the temperature control requirements, it automatically intervenes to adjust the compressor frequency. This solution achieves coordinated control with "flow rate adjustment as the main method and frequency adjustment as the auxiliary method". It prioritizes the rapid response of the vortex tube and adjusts the compressor load when necessary. This ensures both adjustment sensitivity and avoids frequent and large load changes of the compressor, thereby extending equipment life and optimizing energy efficiency.

[0128] It should be understood that the flow rate at the cold and hot ends of the vortex tube 2 is usually controlled by a regulating valve, that is, by opening or closing the regulating valve, the flow rate at the cold and hot ends can be adjusted.

[0129] like Figure 14 As shown, in some application examples of the present invention, the first indoor heat exchanger 4 is used as the target indoor heat exchanger. The lower limit of the preset temperature range is the preset value - t1, and the upper limit of the preset temperature range is the preset value + t2. Only the regulating valve of the hot end outlet 2b of the vortex tube 2 is adjusted. After startup, the heating mode is selected, the compressor 1 operates at the preset frequency, and at the same time, the opening degree K of the regulating valve of the vortex tube 2 operates at the preset opening degree.

[0130] Obtain the actual indoor temperature T of the first indoor heat exchanger 4;

[0131] Compare the actual indoor temperature T with its corresponding preset temperature range;

[0132] When the preset value -t1 < actual indoor temperature T ≤ preset value +t2, the system maintains the current operating state, including the operating frequency of compressor 1 and the opening degree K of the regulating valve of vortex tube 2 (k1 < K).

[0133] When the actual indoor temperature T ≤ preset value - t1 and k1 < regulating valve opening K < k2, then reduce the regulating valve opening K of the hot end outlet 2b. If the regulating valve opening K of the hot end outlet 2b = k1 and the actual indoor temperature T < preset value - t1, then increase the compressor operating frequency so that the temperature meets the condition of "preset value - t1 < actual indoor temperature T ≤ preset value + t2".

[0134] When the actual indoor temperature T > preset value + t2 and k1 < regulating valve opening K < k2, the regulating valve opening K at the hot end outlet 2b is increased. If the regulating valve opening K at the hot end outlet 2b = k2 and the actual indoor temperature T > preset value + t2, the compressor operating frequency is reduced so that the temperature satisfies "preset value - t1 < actual indoor temperature T ≤ preset value + t2".

[0135] Where k1 is the lower limit of the valve opening and k2 is the upper limit of the valve opening.

[0136] It should be noted that the terminology used above is for describing specific embodiments only and is not intended to limit the exemplary embodiments of the present invention. When the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. The order of execution of actions, steps, etc., in the apparatus and methods shown in the specification and drawings may be implemented in any order unless a specific express order is specified, and as long as the output of a previous process is not used in a subsequent process. Similar sequential terms used for ease of description do not imply that such an order must be followed.

[0137] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0138] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly and specifically limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0139] Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as constraints. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0140] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A heat pump system, characterized in that, include: The compressor, vortex tube, first indoor heat exchanger, second indoor heat exchanger, outdoor heat exchanger, first gas-liquid separator, and first intermediate heat exchanger are connected to form a refrigerant circulation loop. The inlet of the vortex tube is connected to the exhaust port of the compressor, the hot end outlet of the vortex tube is connected to the first end of the first indoor heat exchanger in the heating state, and the cold end outlet of the vortex tube is connected to the first end of the second indoor heat exchanger. The first gas-liquid separator is provided with a high-boiling-point fluid port, a low-boiling-point fluid port and a main end, and the first intermediate heat exchanger has a first main pipeline and a first secondary pipeline for mutual heat exchange. The main end of the first gas-liquid separator is connected to the second end of the first indoor heat exchanger, the high boiling point fluid port is connected to the suction side of the compressor, the low boiling point fluid port is connected to the first end of the first main pipeline, the second end of the first main pipeline is connected in series with the main throttling device to the first end of the outdoor heat exchanger, and the second end of the outdoor heat exchanger is connected to the suction side of the compressor in the heating state. The second end of the second indoor heat exchanger is connected in series with the first throttling device and then connected to the first end of the first auxiliary pipeline. The second end of the first auxiliary pipeline is connected to the enthalpy-increasing port of the compressor.

2. The heat pump system according to claim 1, characterized in that, Also includes: A regenerative gas-liquid separator, wherein the regenerative gas-liquid separator is provided with an inlet, an outlet and a regenerative heat exchange pipeline passing through its inner cavity; The outlet of the regenerative gas-liquid separator is connected to the suction port of the compressor, the high-boiling-point fluid port is connected in series with the regenerative heat exchange pipeline and connected to the inlet of the regenerative gas-liquid separator, and the outdoor heat exchanger is connected to the inlet of the regenerative gas-liquid separator in the heating state.

3. The heat pump system according to claim 2, characterized in that, Also includes: The second intermediate heat exchanger has a second main pipeline and a second auxiliary pipeline that exchange heat with each other. The second main pipeline is connected in series between the second end of the first main pipeline and the main throttling device. The high-boiling-point fluid port is connected in series with the regenerating heat exchange pipeline, the second throttling device, and the second auxiliary pipeline to the inlet of the regenerating gas-liquid separator.

4. The heat pump system according to claim 3, characterized in that, Also includes: A four-way valve, wherein the first end of the four-way valve is connected to the hot end outlet of the vortex tube, the second end of the four-way valve is connected to the first end of the first indoor heat exchanger, the third end of the four-way valve is connected to the second end of the outdoor heat exchanger, and the fourth end of the four-way valve is connected to the inlet of the regenerative gas-liquid separator.

5. The heat pump system according to claim 4, characterized in that, The high-boiling-point fluid port is equipped with a control valve for switching its on / off state.

6. The heat pump system according to claim 5, characterized in that, The heat pump system can operate in heating mode; in heating mode, the first and second ends of the four-way valve are connected, the third and fourth ends are connected, and the first throttling device, the second throttling device, and the control valve all operate normally.

7. The heat pump system according to claim 5, characterized in that, The heat pump system can operate in a defrost state; in the defrost state, the first and third ends of the four-way valve are connected, the second and fourth ends are connected, and the first throttling device, the second throttling device, and the control valve are all in a closed state.

8. The heat pump system according to any one of claims 1 to 7, characterized in that, The hot end outlet and / or cold end outlet of the vortex tube are equipped with regulating valves.

9. A heat pump unit, characterized in that, The heat pump unit adopts the heat pump system according to any one of claims 1 to 8.

10. A control method for a heat pump system, said control method being applied to the heat pump system according to any one of claims 1 to 8, characterized in that, include: In heating mode, select either the first indoor heat exchanger or the second indoor heat exchanger as the target indoor heat exchanger. Obtain the actual indoor temperature of the target indoor heat exchanger; Compare the actual indoor temperature with its corresponding preset temperature range; The corresponding outlet flow rate of the vortex tube is controlled based on the comparison results.

11. The control method according to claim 10, characterized in that, The corresponding outlet flow rate of the vortex tube is controlled based on the comparison results, including: When the lower limit of the preset temperature range is less than the actual indoor temperature and less than the upper limit of the preset temperature range, the current operating state of the vortex tube is maintained. When the actual indoor temperature is less than or equal to the lower limit of the preset temperature range, increase the hot end outlet flow rate of the vortex tube and / or decrease the cold end outlet flow rate of the vortex tube. When the actual indoor temperature is greater than the upper limit of the preset temperature range, the hot end outlet flow rate of the vortex tube is reduced and / or the cold end outlet flow rate of the vortex tube is increased.

12. The control method according to claim 11, characterized in that, The control method further includes: When the actual indoor temperature is less than or equal to the lower limit of the preset temperature range, determine whether the hot end outlet flow rate of the vortex tube has risen to the preset upper limit flow rate. If not, increase the hot end outlet flow rate of the vortex tube and / or decrease the cold end outlet flow rate of the vortex tube. If yes, increase the compressor operating frequency. When the actual indoor temperature is greater than the upper limit of the preset temperature range, it is determined whether the hot end outlet flow rate of the vortex tube has dropped to the preset lower limit flow rate. If not, the hot end outlet flow rate of the vortex tube is reduced and / or the cold end outlet flow rate of the vortex tube is increased. If so, the compressor operating frequency is reduced.

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