A multifunctional heat pump based on cascade active jet enthalpy increase and control method

Abstract

The present invention proposes a multifunctional heat pump and control method based on cascade active jet enthalpy increase, which realizes multiple functions such as multi-connected fan cooling, heating, cascade heat pump hot water heating, and cascade active jet enthalpy increase heat pump hot water heating. For multi-connected fan cooling and heating, each fan is independently controlled; for the cascade heat pump, the first stage is a low-temperature jet enthalpy increase heat pump, which provides a heat source for the evaporation side of the second-stage high-temperature heat pump; the heat pump heating generates thermal storage hot water as an external low-grade heat source for the second-stage high-temperature heat pump active jet enthalpy increase; the second stage is a high-temperature active jet enthalpy increase heat pump, and the thermal storage heat is converted into heating capacity in the form of jet enthalpy difference, which greatly improves the performance of the heat pump unit. In addition, jet enthalpy increase is performed during the defrosting process to increase the circulation volume of the refrigerant involved in the defrosting operation, increase the low pressure, speed up the defrosting speed, improve the defrosting effect, and increase the compressor exhaust superheat during the defrosting process to avoid compressor damage due to liquid return during the defrosting process.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pumps, and in particular to a multifunctional heat pump based on cascade active jet enthalpy increase and a control method. Background Art

[0002] Air source heat pump is a heating device that converts electrical energy and air energy into heat through the work of the compressor. However, the heating capacity and energy efficiency are seriously attenuated in low temperature environments, and it cannot be used in extremely low temperature environments. The main solution at present is the jet enthalpy technology, which has been commercialized due to its simple structure and low additional cost. However, the conventional jet enthalpy has great defects, which are manifested as follows: the injection heat of the injected refrigerant comes from the heat pump itself, which is a passive jet enthalpy. The injection enthalpy difference in the jet enthalpy process cannot be converted into heating capacity, and the performance improvement of the heat pump is limited, and it cannot be used in extremely low temperature environments below -20°C. The invention patent with the patent publication number CN111649504A and the name of "Refrigerant Active Jet Heat Pump Based on Solar Energy and Its Control Method" proposes an active jet enthalpy technology based on the heat of an external low-grade heat source. Its principle is: the refrigerant is injected into the economizer to absorb the heat of the external heat source, and the heat of the external heat source is converted into heating capacity in the form of injection enthalpy difference. However, the source of external low-grade heat sources has become a bottleneck in the application of this technology, and how to solve this problem is crucial. Summary of the invention

[0003] In view of the deficiencies in the prior art, the object of the present invention is to provide a multifunctional heat pump based on cascade active jet enthalpy increase and a control method.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] The multifunctional heat pump based on cascade active jet enthalpy increase comprises an outdoor unit module, an indoor unit module, a cascade active jet enthalpy increase heat pump water heater module and a heat storage module.

[0006] The cascade active jet enthalpy-increasing heat pump water heater module and the heat storage module are respectively connected to the outdoor unit module and the indoor unit module through pipelines;

[0007] The outdoor unit module and the indoor unit module are capable of performing heating operation and cooling operation;

[0008] The cascade active jet enthalpy heat pump water heater module comprises a cascade heat exchanger, a high-temperature heat pump compressor, a high-temperature heat pump plate heat exchanger, an active jet enthalpy subcooling electronic expansion valve, and an active jet enthalpy subcooler, wherein the cascade heat exchanger and the outdoor unit module participate in the low-temperature heat pump cycle, the cascade heat exchanger, the high-temperature heat pump compressor, and the high-temperature heat pump plate heat exchanger participate in the high-temperature heat pump cycle, and the high-temperature heat pump plate heat exchanger is used to perform heat exchange with the load side to produce hot water.

[0009] The heat storage module is used to store heat as an external heat source when the outdoor unit module is in heating operation, and the external heat source is used to exchange heat with the refrigerant flowing through the active jet enthalpy increase subcooler when the outdoor unit module is in heating operation.

[0010] Further, the outdoor unit module includes a low-temperature heat pump compressor, an oil separator, a four-way valve, a gas-liquid separator, an outdoor heat exchanger, and a low-temperature heat pump main electronic expansion valve. The low-temperature heat pump exhaust pipe of the low-temperature heat pump compressor is connected to the d pipe of the four-way valve through the oil separator, the e pipe of the four-way valve is connected to the main air pipe, the c pipe of the four-way valve is connected to one end of the outdoor heat exchanger, the s pipe of the four-way valve is connected to the inlet pipe of the gas-liquid separator, the outlet pipe of the gas-liquid separator is connected to the low-temperature compressor return pipe of the low-temperature heat pump compressor, and the other end of the outdoor heat exchanger is connected to the low-temperature heat pump main electronic expansion valve and the high-pressure liquid storage tank in sequence, and the other end of the high-pressure liquid storage tank is connected to the low-temperature heat pump liquid pipe stop valve;

[0011] The indoor unit module includes at least one set of indoor units and indoor electronic expansion valves connected in series. When multiple sets of indoor units and indoor electronic expansion valves are provided, each set of indoor units and indoor electronic expansion valves are connected in parallel with each other.

[0012] The cascade active jet enthalpy-increasing heat pump water heater module comprises a cascade heat exchanger, a cascade heat pump solenoid valve, a high-temperature heat pump compressor, a high-temperature heat pump plate heat exchanger, a high-temperature heat pump main electronic expansion valve, an active jet enthalpy-increasing subcooling electronic expansion valve, an active jet enthalpy-increasing subcooler and a high-temperature heat pump water pump;

[0013] The high-temperature heat pump exhaust pipe of the high-temperature heat pump compressor is connected to the inlet pipe of the high-temperature heat pump plate heat exchanger, the outlet pipe of the high-temperature heat pump plate heat exchanger is connected to the high-temperature heat pump main electronic expansion valve and the heat exchange inlet pipe of the cascade heat exchanger in sequence, the heat exchange outlet pipe of the cascade heat exchanger is connected to the return air pipe of the high-temperature compressor, the hot water inlet pipe and the hot water outlet pipe of the high-temperature plate heat exchanger are respectively connected to the load side, and a high-temperature heat pump water pump is installed on the hot water outlet pipe, and the high-temperature heat pump water pump pumps hot water to circulate in the high-temperature heat pump plate heat exchanger and the load side;

[0014] One end of the active jet enthalpy-added supercooling electronic expansion valve is connected to the outlet pipe of the high-temperature heat pump plate heat exchanger, the other end of the active jet enthalpy-added supercooling electronic expansion valve is connected to the active jet enthalpy-added inlet pipe of the active jet enthalpy-added supercooler, the active jet enthalpy-added injection pipe of the active jet enthalpy-added supercooler is connected to the jet enthalpy-added injection port of the high-temperature heat pump compressor, and the heating hot water inlet pipe and the heating hot water outlet pipe of the active jet enthalpy-added supercooler are respectively connected to the heat storage module;

[0015] The heat storage module includes a heat storage module solenoid valve, a heat storage module plate heat exchanger, a heat storage module electronic expansion valve, a heat storage water tank, a heat storage hot water pump and an active jet reheat-increasing water pump. The heat storage water tank is connected with a heat storage hot water return pipe, a heat storage hot water outlet pipe, a heating hot water return pipe and a heating hot water outlet pipe. The heat storage hot water pump pumps hot water through the heat storage hot water return pipe and the heat storage hot water outlet pipe to circulate between the heat storage module plate heat exchanger and the heat storage water tank. The active jet reheat-increasing water pump pumps hot water through the heating hot water return pipe and the heating hot water outlet pipe to circulate between the heat storage water tank and the active jet reheat-increasing supercooler.

[0016] Furthermore, the outdoor unit module also includes a conventional jet reheat enthalpy subcooler and a conventional jet reheat enthalpy subcooling electronic expansion valve, the conventional jet reheat enthalpy subcooler is connected with a conventional jet reheat enthalpy injection inlet pipe, a conventional jet reheat enthalpy injection pipe, a liquid storage tank outlet pipe, and a main liquid pipe, the conventional jet reheat enthalpy subcooling electronic expansion valve is connected to the conventional jet reheat enthalpy subcooling electronic expansion valve through two pipelines, wherein the injection inlet pipe is connected between the inlet end of the conventional jet reheat enthalpy subcooling electronic expansion valve and the liquid pipe section between the high-pressure liquid storage tank and the conventional jet reheat enthalpy subcooler, the injection outlet pipe is connected between the outlet end of the conventional jet reheat enthalpy subcooling electronic expansion valve and the conventional jet reheat enthalpy subcooling electronic expansion valve, the conventional jet reheat enthalpy injection pipe is connected to the injection port of the low-temperature stage heat pump compressor, and the injection refrigerant is injected into the intermediate pressure chamber of the compressor, the main liquid pipe connects the conventional jet reheat enthalpy subcooler and the outdoor heat exchanger, and the main electronic expansion valve is connected to the main liquid pipe.

[0017] Furthermore, it also includes a temperature detection module, which includes a water temperature sensor for a hot water storage tank, a jet enthalpy water inlet temperature sensor, a jet enthalpy water outlet temperature sensor, a jet enthalpy refrigerant inlet temperature sensor, a jet enthalpy refrigerant outlet temperature sensor, a liquid pipe temperature sensor, a hot water outlet temperature sensor generated by a heat pump, a return water temperature sensor, a fan coil liquid pipe temperature sensor, a fan coil air pipe temperature sensor, and a fan coil return air temperature sensor. The water temperature sensor for the hot water storage tank is used to detect the actual hot water temperature T in the hot water storage tank. tank,cur The jet enthalpy water inlet temperature sensor is used to detect the active jet enthalpy hot water inlet temperature T w,inj,in The jet enthalpy water outlet temperature sensor is used to detect the active jet enthalpy hot water outlet temperature T w,inj,out The jet enthalpy refrigerant inlet temperature sensor is used to detect the active jet enthalpy refrigerant inlet temperature T ref,inj,in The jet enthalpy refrigerant outlet temperature sensor is used to detect the active jet enthalpy refrigerant outlet temperature T ref,inj,out The liquid pipe temperature sensor is used to detect the liquid pipe temperature T liq The return water temperature sensor is used to detect the return water temperature T w,in,curThe fan disk return air temperature sensor is used to detect the return air temperature of the fan disk unit, the fan disk liquid pipe temperature sensor is used to detect the liquid pipe temperature of the fan disk unit, and the fan disk air pipe temperature sensor is used to detect the air pipe temperature of the fan disk unit.

[0018] A multifunctional heat pump control method based on cascade active jet enthalpy increase is applied to the multifunctional heat pump based on cascade active jet enthalpy increase as described above, and is characterized in that: it includes a cooling operation control step, a heating operation control step and a hot water operation control step, and the cooling operation control step or the heating operation control step or the hot water operation control step is executed based on the command of the wire controller;

[0019] The refrigeration operation control step comprises:

[0020] Step S1A: a preset cooling operation start condition is configured. When the cooling operation start condition is met, the cooling operation control is turned on.

[0021] Step S1B: a preset refrigeration operation shut-off condition is configured, and when the refrigeration operation shut-off condition is met, refrigeration operation control is terminated;

[0022] The heating operation control step comprises:

[0023] Step S2A: a preset heating operation start condition is configured. When the heating operation start condition is met, the heating operation control is turned on.

[0024] Step S2B: a preset heating operation shut-down condition is configured, and when the heating operation shut-down condition is met, the heating operation control is shut down;

[0025] The hot water production operation control step includes:

[0026] Step S3A: a preset start-up condition for producing thermal storage hot water is configured. When the start-up condition for producing thermal storage hot water is met, the control for producing thermal storage hot water is started;

[0027] Step S3B: a preset shutdown condition for producing thermal storage hot water is configured. When the shutdown condition for producing thermal storage hot water is met, the thermal storage hot water production operation control is shut down;

[0028] Step S4A: a preset cascade heat pump hot water operation start-up condition is configured, and when the cascade heat pump hot water operation start-up condition is met, the cascade heat pump hot water operation control is started;

[0029] Step S4B: a preset cascade heat pump hot water operation shut-down condition is configured, and when the cascade heat pump hot water operation shut-down condition is met, the cascade heat pump hot water operation control is shut down;

[0030] Step S5A: a preset cascade active jet enthalpy heat pump hot water operation start-up condition is configured, and when the cascade active jet enthalpy heat pump hot water operation start-up condition is met, the cascade active jet enthalpy heat pump hot water operation is started;

[0031] Step S5B: The preset cascade active jet enthalpy heat pump hot water operation shutdown condition and the heat pump hot water shutdown condition are configured. When the cascade active jet enthalpy heat pump hot water operation shutdown condition is met, the cascade active jet enthalpy heat pump hot water operation is shut down, and the cascade heat pump hot water operation control is performed. When the heat pump hot water shutdown condition is met, the cascade active jet enthalpy heat pump water heater module is shut down.

[0032] Furthermore, in step S1A, the cooling operation start condition is specifically that the return air temperature is detected to be greater than the sum of the preset cooling temperature and the return air temperature return difference threshold.

[0033] In step S1B, the cooling operation shut-down condition is specifically that the return air temperature is detected to be less than or equal to the difference between the preset cooling temperature and the return air temperature return difference threshold.

[0034] Further, in step S2A, the heating operation start condition is specifically that the return air temperature is detected to be less than the difference between the preset heating temperature and the return air temperature return difference threshold.

[0035] In step S2B, the heating operation shut-down condition is specifically that it is detected that the return air temperature is greater than the sum of the preset heating temperature and the return air temperature return difference threshold.

[0036] Further, in step S3A, the thermal storage hot water production operation start condition is configured with a preset first ambient temperature threshold and a water temperature setting target value. When it is detected that the outdoor ambient temperature is lower than the preset first ambient temperature threshold and the duration reaches the preset duration, and when it is detected that the actual stored water temperature is lower than the difference between the water temperature setting target value and the preset first stored water temperature return difference temperature and the duration reaches the preset duration, it is deemed that the thermal storage hot water production operation start condition is met;

[0037] In step S3B, the thermal storage hot water production operation shut-down condition is configured with a preset second thermal storage water temperature hysteresis temperature. When it is detected that the actual thermal storage hot water temperature is higher than the sum of the water temperature setting target value and the second thermal storage water temperature hysteresis temperature, and the duration reaches a preset time, the thermal storage hot water production operation shut-down condition is deemed to be met.

[0038] Further, in step S4A, the cascade heat pump hot water operation start-up condition is configured with a preset return water temperature target value and a preset first return water return temperature difference. When the detected return water temperature is less than the difference between the return water temperature target value and the first return water return temperature difference, and the duration reaches a preset time, the cascade heat pump hot water operation start-up condition is deemed to be met;

[0039] In step S4B, the cascade heat pump hot water operation shut-down condition is configured with a preset second return water return temperature difference. When the detected return water temperature is greater than the sum of the return water temperature target value and the preset second return water return temperature difference, and the duration reaches a preset time, the cascade heat pump hot water operation shut-down condition is deemed to be met.

[0040] Further, the exhaust superheat is defined as the exhaust temperature detected by the exhaust temperature sensor of the high-temperature heat pump compressor minus the saturation temperature corresponding to the high-pressure pressure detected by the high-pressure pressure sensor;

[0041] In step S5A, the cascade active jet enthalpy heat pump hot water operation start-up condition is configured with a preset second ambient temperature threshold, a first exhaust superheat target value, and a thermal storage hot water temperature hysteresis setting threshold. When it is detected that the outdoor ambient temperature is lower than the second ambient temperature threshold, and the cascade heat pump is turned on and runs for more than a preset running time, it is detected that the exhaust superheat is greater than the preset first exhaust superheat target value, and it is detected that the thermal storage hot water temperature is greater than the sum of the liquid pipe temperature and the thermal storage hot water temperature hysteresis setting threshold and the duration exceeds a preset time, it is deemed that the cascade active jet enthalpy heat pump hot water operation start-up condition is met;

[0042] In step S5B, the cascade active jet enthalpy heat pump hot water operation shut-down condition is configured with a third ambient temperature threshold, a second exhaust superheat target value and a hysteresis setting value. When it is detected that the outdoor ambient temperature is higher than the third ambient temperature threshold, or the exhaust superheat is less than the preset second exhaust superheat target value, or when the active jet enthalpy hot water inlet temperature is less than or equal to the sum of the active jet enthalpy refrigerant outlet temperature and the hysteresis setting value, or the active jet enthalpy hot water outlet temperature is less than or equal to the sum of the active jet enthalpy refrigerant inlet temperature and the hysteresis setting value, the cascade active jet enthalpy heat pump hot water operation shut-down condition is deemed to be met;

[0043] In step S5B, the heat pump hot water shutdown condition is configured with a return water temperature target value and a return water temperature hysteresis threshold. When the return water temperature is detected to be higher than the sum of the return water temperature target value and the return water temperature hysteresis threshold, the heat pump hot water shutdown condition is deemed to be met.

[0044] Furthermore, the method further comprises step S6A: configuring a preset defrost entry determination condition, and starting the defrost operation control when the defrost entry determination condition is met;

[0045] Step S6B: a preset defrost termination determination condition is configured, and when the defrost termination determination condition is met, the defrost operation control is turned off.

[0046] Beneficial effects of the present invention:

[0047] The present invention proposes a multifunctional heat pump based on cascade active jet enthalpy increase and a control method thereof, which realizes multiple functions such as multi-connected fan disk cooling, fan disk heating, single heat storage, cascade heat pump hot water, and cascade active jet enthalpy increase heat pump hot water. For the cascade heat pump, the first stage is a low-temperature conventional jet enthalpy increase heat pump, which increases the degree of supercooling through conventional jet enthalpy increase to absorb more air energy and provide a heat source for the evaporation side of the second high-temperature heat pump; the heat pump heating generates thermal storage hot water as an external low-grade heat source for the second high-temperature heat pump active jet enthalpy increase; the second stage is a high-temperature active jet enthalpy increase heat pump, and the thermal storage heat is converted into heating capacity in the form of jet enthalpy difference, which greatly improves the performance of the heat pump unit. In addition, when the system is defrosted, the high-temperature heat pump system does not participate in defrosting and maintains heating operation. The low-temperature heat pump uses the stored heat for heat storage defrosting, and the defrosting process uses jet enthalpy increase to increase the circulation volume of refrigerant involved in the defrosting operation, increase the low pressure, speed up the defrosting speed, improve the defrosting effect, and increase the compressor exhaust superheat during the defrosting process to avoid compressor damage due to liquid return during the defrosting process. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic diagram of the principle of the multifunctional heat pump based on cascade active jet enthalpy increase in the present invention;

[0049] Figure 2 It is a schematic diagram of the flow path of the multi-unit refrigeration cycle in the present invention;

[0050] Figure 3 It is a schematic diagram of the flow path of the thermal cycle of the multi-unit mechanism in the present invention;

[0051] Figure 4 It is a schematic diagram of the flow path of a single heat storage cycle in the present invention;

[0052] Figure 5 It is a schematic diagram of the flow path of the conventional jet enthalpy-increasing heat pump hot water cycle in the present invention;

[0053] Figure 6 It is a schematic diagram of the flow path of the active jet enthalpy-increasing heat pump for producing hot water circulation in the present invention;

[0054] Figure 7 It is a schematic diagram of the flow path of the multi-unit heat generation + heat storage cycle in the present invention;

[0055] Figure 8 is a schematic diagram of the flow path of the defrost cycle in the present invention;

[0056] Fig. 9 is a schematic diagram of an active jet enthalpy-increasing subcooler in the present invention;

[0057] Fig.10 It is a flow chart of a multifunctional heat pump control method based on cascade active jet enthalpy increase in the present invention.

[0058] Reference numerals:

[0059] Low temperature heat pump compressor; 2. Low temperature heat pump exhaust pipe; 3. Oil separator; 4. Main solenoid valve; 5. Four-way valve; 6. Main gas pipe; 7. Gas pipe stop valve of low temperature heat pump; 8. Liquid pipe stop valve of low temperature heat pump; 9. High pressure liquid storage tank; 10. Conventional jet enthalpy increase subcooler; 11. Main electronic expansion valve of low temperature heat pump; 12. Outdoor heat exchanger; 13. Return air pipe of low temperature compressor; 14. Gas-liquid separator; 15. Conventional jet enthalpy increase subcooling electronic expansion valve; 16. Conventional jet enthalpy increase injection pipe; 17. Stop valve; 18. High pressure pressure sensor of low temperature heat pump; 19. Low pressure pressure sensor of low temperature heat pump; 20. Suction temperature sensor of low temperature heat pump; 21A, 21B, 21C, fan unit; 22A, 22B, 22C, indoor electronic expansion valve; 23A, 23B, 23C, air disk liquid pipe temperature sensor; 24A, 24B, 24C, air disk gas pipe temperature sensor; 25A, 25B, 25C, air disk return air temperature sensor; 31, thermal storage module gas pipe stop valve; 32, thermal storage module solenoid valve; 33, thermal storage module plate heat exchanger; 34, thermal storage module electronic expansion valve; 35, cascade heat pump solenoid valve; 36, cascade heat exchanger; 37, one-way valve; 38, thermal storage module liquid pipe stop valve; 41. High-temperature heat pump compressor; 42. High-temperature heat pump exhaust pipe; 43. High-temperature heat pump plate heat exchanger; 44. High-temperature heat pump main electronic expansion valve; 45. Active jet enthalpy increase subcooling electronic expansion valve; 46. Active jet enthalpy increase subcooler; 47. Active jet enthalpy increase injection pipe; 48. Load side; 49. High-temperature heat pump water pump; 50. Heat storage tank; 51. Heat storage hot water pump; 52. Active jet enthalpy increase pump; 53. Heat storage water Box water temperature sensor; 54, jet enthalpy inlet water temperature sensor; 55, jet enthalpy outlet water temperature sensor; 56, jet enthalpy refrigerant inlet temperature sensor; 57, jet enthalpy refrigerant outlet temperature sensor; 58, liquid pipe temperature sensor; 59, hot water outlet temperature sensor generated by heat pump; 60, hot water return temperature sensor generated by heat pump; 61, high-temperature heat pump high-pressure sensor; 62, high-temperature heat pump exhaust temperature sensor. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a component centered. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a component centered. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a component centered. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0062] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0063] like Figure 1 As shown, a multifunctional heat pump based on cascade active jet reheat enthalpy increase in this embodiment includes an outdoor unit module, a cascade active jet reheat enthalpy increase heat pump water heater module and a heat storage module. The cascade active jet reheat enthalpy increase heat pump water heater module and the heat storage module are respectively connected to the outdoor unit module and the heat storage module through connecting pipes.

[0064] The outdoor unit module includes a low-temperature heat pump gas pipe stop valve 7 and a low-temperature heat pump liquid pipe stop valve 8. The outdoor unit module and the indoor unit module are connected to form a loop through the low-temperature heat pump gas pipe stop valve 7 and the low-temperature heat pump liquid pipe stop valve 8.

[0065] The outdoor unit module includes a low-temperature heat pump compressor 1, an oil separator 3, a four-way valve 5, a gas-liquid separator 14, an outdoor heat exchanger 12, a low-temperature heat pump main electronic expansion valve 11, a conventional jet enthalpy-increasing subcooler 10 and a conventional jet enthalpy-increasing subcooling electronic expansion valve 15. The low-temperature heat pump exhaust pipe 2 of the low-temperature heat pump is connected to the d pipe of the four-way valve 5 through the oil separator 3, the e pipe of the four-way valve 5 is connected to the main air pipe 6, the c pipe of the four-way valve 5 is connected to one end of the outdoor heat exchanger 12, the s pipe of the four-way valve 5 is connected to the inlet pipe of the gas-liquid separator 14, and the outlet pipe of the gas-liquid separator 14 is connected to the low-temperature compressor return pipe 13 of the low-temperature heat pump compressor 1. The other end of the outdoor heat exchanger 12 is connected to the low-temperature heat pump main electronic expansion valve 11, the conventional jet enthalpy-increasing subcooler 10, and the high-pressure liquid storage tank 9 in sequence, and the other end of the high-pressure liquid storage tank 9 is connected to the low-temperature heat pump liquid pipe stop valve 8. When the unit is installed, the low-temperature heat pump gas pipe stop valve 7 and the heat storage module gas pipe stop valve 31 are connected through a connecting pipe, and the low-temperature heat pump liquid pipe stop valve 8 and the heat storage module liquid pipe stop valve 38 are connected through a connecting pipe.

[0066] The indoor unit module includes at least one group of series-connected air disk indoor units 21 and indoor unit electronic expansion valves 22. When multiple groups of air disk indoor units and indoor unit electronic expansion valves are provided, each group of air disk indoor units and indoor unit electronic expansion valves are connected in parallel with each other; wherein one end of the air disk indoor unit 21 is connected to the gas pipe stop valve 7 of the low-temperature heat pump, and the other end of the indoor unit electronic expansion valve 22 is connected to the low-temperature heat pump liquid pipe stop valve 8.

[0067] The conventional jet enthalpy-increasing supercooler 10 is connected with a conventional jet enthalpy-increasing injection inlet pipe, a conventional jet enthalpy-increasing injection pipe 16, a liquid storage tank outlet pipe, and a main liquid pipe. The conventional jet enthalpy-increasing injection inlet pipe is connected to the liquid pipe section between the high-pressure liquid storage tank 9 and the conventional jet enthalpy-increasing supercooler 10, and the conventional jet enthalpy-increasing supercooler 15 is connected to the conventional jet enthalpy-increasing supercooler 10 through two pipelines, wherein the injection inlet pipe is connected between the inlet end of the conventional jet enthalpy-increasing supercooling electronic expansion valve 15 and the liquid pipe section between the high-pressure liquid storage tank 9 and the conventional jet enthalpy-increasing supercooler 10, and the injection outlet pipe is connected between the outlet end of the conventional jet enthalpy-increasing supercooling electronic expansion valve 15 and the conventional jet enthalpy-increasing supercooler 10. The conventional jet reheat injection pipe 16 is connected to the injection port of the low-temperature heat pump compressor 1, and the injection refrigerant is injected into the intermediate pressure chamber of the low-temperature heat pump compressor 1. The main liquid pipe connects the conventional jet reheat subcooler 10 and the outdoor heat exchanger 12, and the low-temperature heat pump main electronic expansion valve 11 is connected to the main liquid pipe.

[0068] The cascade active jet heat pump water heater module includes a heat storage module gas pipe stop valve 31 and a heat storage module liquid pipe stop valve 38, and the cascade active jet heat pump water heater module is connected to the outdoor unit module and the indoor unit module through an external connecting pipe. The heat storage module gas pipe stop valve 31 is connected to the stop valve 17 in the outdoor unit module through a connecting pipe, and the stop valve 17 is connected to the outlet pipe of the oil separator, so that the refrigerant flowing through the oil separator 3 is divided into two paths, one flowing to the four-way valve 5, and the other flowing to the heat storage module gas pipe stop valve 31. The heat storage module liquid pipe stop valve 38 is connected to the low temperature heat pump liquid pipe stop valve 8 in the outdoor unit module through a connecting pipe.

[0069] The cascade active jet reheating heat pump water heater module includes a cascade heat exchanger 36, a cascade heat pump solenoid valve 35, a high-temperature heat pump compressor 41, a high-temperature heat pump plate heat exchanger 43, a high-temperature heat pump main electronic expansion valve 44, an active jet reheating subcooling electronic expansion valve 45, an active jet reheating subcooler 46 and a high-temperature heat pump water pump 49.

[0070] The cascade heat exchanger 36, the cascade heat pump solenoid valve 35, the high-temperature heat pump compressor 41, the high-temperature heat pump plate heat exchanger 43, and the high-temperature heat pump main electronic expansion valve 44 participate in the high-temperature heat pump cycle. The high-temperature heat pump exhaust pipe 42 of the high-temperature heat pump compressor 41 is connected to the inlet pipe of the high-temperature heat pump plate heat exchanger 43, and the outlet pipe of the high-temperature heat pump plate heat exchanger 43 is connected to the inlet pipe of the high-temperature heat pump main electronic expansion valve 44 and the cascade heat exchanger 36 in sequence, and the outlet pipe of the cascade heat exchanger 36 is connected to the high-temperature compressor return pipe of the high-temperature heat pump compressor 41. The hot water inlet pipe and the hot water outlet pipe of the high-temperature plate heat exchanger are respectively connected to the load side 48, and a high-temperature heat pump water pump 49 is installed on the hot water outlet pipe. The high-temperature heat pump water pump 49 pumps hot water to circulate between the high-temperature heat pump plate heat exchanger 43 and the load side 48.

[0071] The heat storage module includes a heat storage module solenoid valve 32, a heat storage module plate heat exchanger 33, a heat storage water tank 50, a heat storage hot water pump 51, an active jet enthalpy increase water pump 52 and a water temperature sensor 53 for the heat storage water tank. The heat storage water tank 50 is connected with a heat storage hot water inlet pipe, a heat storage hot water outlet pipe, a heating hot water inlet pipe and a heating hot water outlet pipe. The heat storage hot water pump 51 pumps hot water through the heat storage hot water inlet pipe and the heat storage hot water outlet pipe to circulate between the heat storage module plate heat exchanger 33 and the heat storage water tank 50, so as to realize heat storage when the heat pump system is in heating operation. The active jet reheat water pump 52 pumps hot water to circulate between the active jet reheat subcooler 46 and the hot water storage tank 50, and uses the heat storage module as an external heat source for active jet reheat. The heat from the external heat source is converted into heating capacity in the form of a jet enthalpy difference, which greatly improves the performance of the unit, achieves ultra-high energy efficiency, and solves the technical bottleneck that the heat pump cannot be used in extremely low temperature environments.

[0072] The active jet enthalpy-added subcooling electronic expansion valve 45 and the active jet enthalpy-added subcooler 46 participate in the active jet enthalpy-added heat pump cycle. One end of the active jet enthalpy-added subcooling electronic expansion valve 45 is connected to the outlet pipe of the high-temperature stage heat pump plate heat exchanger 43, and the other end of the active jet enthalpy-added subcooling electronic expansion valve 45 is connected to the active jet enthalpy-added inlet pipe of the active jet enthalpy-added subcooler 46. The active jet enthalpy-added jet pipe 47 of the active jet enthalpy-added subcooler 46 is connected to the high-temperature stage heat pump compressor 41. The heating hot water inlet pipe and the heating hot water outlet pipe of the active jet enthalpy-added subcooler 46 are respectively connected to the hot water storage tank 50 of the heat storage module, and the heat storage module can be used as an external heat source of the active jet enthalpy-added subcooler 46.

[0073] The heat storage module gas pipe stop valve 31 is connected to the cascade heat pump electromagnetic valve 35, and the heat storage module gas pipe stop valve 31 is connected to the inlet pipe of the heat storage module plate heat exchanger 33 through the electromagnetic valve 32. The outlet pipe of the heat storage module electromagnetic valve 32 is connected to the refrigerant inlet end of the heat storage module plate heat exchanger 33, and the heat storage module plate heat exchanger 33 is connected to the pipeline between the cascade heat pump check valve 37 and the heat storage module liquid pipe stop valve 38. The heat storage module plate heat exchanger 33 is connected with a heat storage hot water inlet pipe and a heat storage hot water outlet pipe, and is connected to the heat storage water tank 50 through the heat storage hot water inlet pipe and the heat storage hot water outlet pipe, so that heat can be stored.

[0074] See also Figure 1 and Fig. 9 , further comprising a temperature detection module, the temperature detection module comprising a water temperature sensor 53 for a hot water storage tank, a jet enthalpy water inlet temperature sensor 54, a jet enthalpy water outlet temperature sensor 55, a jet enthalpy refrigerant inlet temperature sensor 56, a jet enthalpy refrigerant outlet temperature sensor 57, a liquid pipe temperature sensor 58, a hot water outlet temperature sensor 59 generated by a heat pump, a return water temperature sensor 60, a fan coil liquid pipe temperature sensor 23, a fan coil air pipe temperature sensor 24 and a fan coil return air temperature sensor 25, the hot water storage tank water temperature sensor 53 is used to detect the actual hot water temperature T in the hot water storage tank 50 tank,cur The jet enthalpy water inlet temperature sensor 54 is used to detect the active jet enthalpy hot water inlet temperature T w,inj,in The jet enthalpy water outlet temperature sensor 55 is used to detect the active jet enthalpy hot water outlet temperature T w,inj,out The jet enthalpy refrigerant inlet temperature sensor 56 is used to detect the active jet enthalpy refrigerant inlet temperature T ref,inj,in The jet enthalpy refrigerant outlet temperature sensor 57 is used to detect the active jet enthalpy refrigerant outlet temperature T ref , inj,out The liquid pipe temperature sensor 58 is used to detect the liquid pipe temperature T liq The hot water outlet temperature sensor 59 generated by the heat pump is used to detect the outlet water temperature T w,out,cur The return water temperature sensor 60 is used to detect the return water temperature T w,in,cur The fan disk return air temperature sensor 25 is used to detect the return air temperature of the fan disk internal unit 21 .

[0075] The cycles of the multifunctional heat pump system based on cascade active jet enthalpy increase in this embodiment include: 1. Multi-unit refrigeration cycle; 2. Multi-unit heating cycle; 3. Heat pump single heat storage cycle; 4. Conventional heat pump hot water cycle; 5. Active jet enthalpy increase heat pump hot water cycle; 6. Multi-unit heating + heat storage cycle; 7. Defrosting cycle. In order to clearly introduce the operating cycle principle of this application, the following is an introduction based on the operating cycle mode in combination with the flow diagram:

[0076] 1. Multi-unit refrigeration cycle

[0077] See also Figure 2 In the multi-unit refrigeration cycle mode, the refrigerant discharged from the low-temperature heat pump compressor 1 passes through the oil separator 3, the d pipe of the four-way valve 5, the c pipe of the four-way valve 5, the outdoor heat exchanger 12, the low-temperature heat pump main electronic expansion valve 11, the conventional jet enthalpy increase subcooler 10, the high-pressure liquid storage tank 9, and the low-temperature heat pump liquid pipe stop valve 8 before reaching the indoor unit. One or more of the indoor electronic expansion valves 22A, 22B, and 22C are opened, and the refrigerant flows through the corresponding fan disk indoor unit 21A, 21B or 21C for refrigeration, and then the refrigerant passes through the low-temperature heat pump gas pipe stop valve 7, the e pipe of the four-way valve 5, the s pipe of the four-way valve 5, and the gas-liquid separator 14 before returning to the low-temperature heat pump compressor 1.

[0078] 2. Multi-link thermal cycle

[0079] See also Figure 3 In the multi-split heating cycle mode, the refrigerant discharged from the low-temperature heat pump compressor 1 passes through the oil separator 3, the d pipe of the four-way valve 5, the e pipe of the four-way valve 5, and the low-temperature heat pump gas pipe stop valve 7 before entering the indoor unit module. One or more of the indoor electronic expansion valves 22A, 22B, and 22C are opened, and the refrigerant flows through the corresponding fan disk indoor unit 21A, 21B or 21C for heating. Then the refrigerant passes through the low-temperature heat pump liquid pipe stop valve 8, the high-pressure liquid storage tank 9, the conventional jet enthalpy increase subcooler 10, the low-temperature heat pump main electronic expansion valve 11, and the outdoor heat exchanger 12 in turn, and then passes through the c pipe of the four-way valve, the s pipe of the four-way valve, and the gas-liquid separator 14 before returning to the low-temperature heat pump compressor 1.

[0080] In the heating cycle mode, in order to prevent the refrigerant from accumulating in the unpowered indoor unit 21 of the fan, the corresponding indoor unit electronic expansion valve 22 is usually opened to a certain degree to allow only the refrigerant to circulate.

[0081] During the heating process, the conventional jet reheat enthalpy subcooling electronic expansion valve 15 can be opened for conventional jet reheat enthalpy. At this time, another part of the refrigerant in the liquid pipe enters the conventional jet reheat enthalpy subcooler 10 after throttling by the conventional jet reheat enthalpy subcooling electronic expansion valve 15 to exchange heat with the refrigerant in the main liquid pipe, and then is injected into the injection port of the low-temperature stage heat pump compressor 1 through the conventional jet reheat enthalpy injection pipe 16.

[0082] 3. Heat pump single heat storage cycle

[0083] See also Figure 4In the heat pump single heat storage cycle mode, the heat storage module participates in the work. The refrigerant discharged from the low-temperature heat pump compressor 1 passes through the oil separator 3, the stop valve 17, the heat storage module gas pipe stop valve 31, and the heat storage module solenoid valve 32, and then enters the heat storage module plate heat exchanger 33. The heat storage hot water pump 51 pumps the hot water in the heat storage water tank 50 to circulate. The hot water absorbs the heat released by the refrigerant flowing through the heat storage module plate heat exchanger 33 and is stored in the heat storage water tank 50. The refrigerant condenses after passing through the heat storage module plate heat exchanger 33, and enters the low-temperature heat pump main unit through the heat storage module electronic expansion valve 34, the heat storage module liquid pipe stop valve 38, and the low-temperature heat pump liquid pipe stop valve 8. A part of the refrigerant in the liquid pipe passes through the main liquid pipe of the conventional jet reheat-increasing subcooler 10, the low-temperature heat pump main electronic expansion valve 11, the outdoor heat exchanger 12, the c pipe of the four-way valve 5, and the s pipe of the four-way valve 5, and returns to the suction port of the low-temperature heat pump compressor 1 after passing through the gas-liquid separator 14; another part of the refrigerant in the liquid pipe enters the conventional jet reheat-increasing subcooler 10 after throttling through the conventional jet reheat-increasing subcooling electronic expansion valve 15, exchanges heat with the refrigerant in the main liquid pipe, and then is sprayed to the injection port of the low-temperature heat pump compressor 1 through the conventional jet reheat-increasing injection pipe 16.

[0084] 4. Conventional heat pump hot water operation mode

[0085] See also Figure 5 The heat pump hot water cycle includes a low-temperature heat pump cycle and a high-temperature heat pump cycle. It should be noted that the low-temperature heat pump cycle and the high-temperature heat pump cycle cannot operate independently, and both need to work synchronously. For ease of understanding, the low-temperature heat pump cycle and the high-temperature heat pump cycle are introduced separately in this application.

[0086] In the low-temperature heat pump cycle, the cascade heat exchanger 36 acts as a condenser, and the refrigerant in the low-temperature heat pump cycle transfers heat to the refrigerant in the high-temperature heat pump cycle and condenses, and then passes through the low-temperature heat pump main electronic expansion valve 11 for throttling, and returns to the low-temperature heat pump compressor 1 after absorbing air energy through the outdoor heat exchanger, and re-enters the cascade heat exchanger 36 after being compressed by the low-temperature heat pump compressor 1. The specific cycle process is as follows:

[0087] Please refer to the flow diagram Figure 5The high-temperature and high-pressure refrigerant discharged from the low-temperature heat pump compressor 1 passes through the oil separator 3, passes through the heat storage module gas pipe stop valve 31, and the cascade heat pump solenoid valve 35, and then enters the cascade heat exchanger 36. In the cascade heat exchanger 36, it exchanges heat with the refrigerant circulating in the high-temperature heat pump and then condenses. It passes through the cascade heat pump check valve 37, the heat storage module liquid pipe stop valve 38, and the low-temperature heat pump liquid pipe stop valve 8 and enters the conventional jet enthalpy heat pump outdoor unit. A part of the refrigerant in the liquid pipe passes through the conventional jet enthalpy heat pump. The main liquid pipe of the enthalpy subcooler 10, the low-temperature heat pump main electronic expansion valve 11, the outdoor heat exchanger 12, the c pipe of the four-way valve 5, and the s pipe of the four-way valve 5 return to the suction port of the low-temperature heat pump compressor 1 after passing through the gas-liquid separator 14; the other part of the refrigerant in the liquid pipe enters the conventional jet enthalpy subcooling electronic expansion valve 15 after throttling and enters the conventional jet enthalpy subcooler 10 to exchange heat with the refrigerant in the main liquid pipe, and then is sprayed to the injection port of the low-temperature heat pump compressor 1 through the conventional jet enthalpy injection pipe 16.

[0088] In the high-temperature heat pump cycle, the refrigerant circulating in the low-temperature heat pump transfers heat to the evaporation side of the high-temperature heat pump. The cascade heat exchanger 36 serves as the evaporator of the high-temperature heat pump, so that the refrigerant circulating in the high-temperature stage absorbs heat from the refrigerant circulating in the low-temperature stage. The specific cycle process is as follows:

[0089] Please refer to the flow diagram Figure 5 The refrigerant circulating in the high temperature stage is compressed by the high temperature stage heat pump compressor 41, and enters the high temperature stage heat pump plate heat exchanger 43 through the high temperature stage heat pump exhaust pipe 42 of the high temperature stage heat pump compressor 41. The high temperature stage heat pump water pump 49 pumps hot water to circulate in the load side 48 and the high temperature stage heat pump plate heat exchanger 43, so that the hot water absorbs the heat of the refrigerant in the high temperature stage heat pump plate heat exchanger 43 and supplies the heat to the load side 48. After the refrigerant flows out of the high temperature stage heat pump plate heat exchanger 43, it is throttled by the high temperature stage heat pump main electronic expansion valve 44 and enters the cascade heat exchanger 36. In the cascade heat exchanger 36, the refrigerant circulating in the low temperature stage heat pump transfers heat to the refrigerant circulating in the high temperature stage heat pump, and then the refrigerant circulating in the high temperature stage heat pump returns to the high temperature stage heat pump compressor 41.

[0090] 5. Active jet enthalpy-increasing heat pump to produce hot water circulation

[0091] On the basis of the heat pump hot water production cycle, the active jet enthalpy increase subcooler 46 and the active jet enthalpy increase subcooling electronic expansion valve 45 participate in the active jet enthalpy increase heat pump single hot water production cycle.

[0092] Please refer to the flow diagram Figure 6The refrigerant circulating in the high-temperature stage is compressed by the high-temperature stage heat pump compressor 41, and enters the high-temperature stage heat pump plate heat exchanger 43 through the high-temperature stage heat pump exhaust pipe 42 of the high-temperature stage heat pump compressor 41. The high-temperature stage heat pump water pump 49 pumps hot water to circulate between the high-temperature stage heat pump plate heat exchanger 43 and the load side 48, so that the hot water absorbs the heat of the refrigerant in the high-temperature stage heat pump plate heat exchanger 43, and supplies the hot water to the load side 48. After the refrigerant flows out of the high-temperature heat pump plate heat exchanger 43, it is throttled by the high-temperature heat pump main electronic expansion valve 44 and enters the cascade heat exchanger 36. In the cascade heat exchanger 36, the refrigerant circulating in the low-temperature heat pump transfers heat to the refrigerant circulating in the high-temperature heat pump, and then the refrigerant circulating in the high-temperature heat pump returns to the high-temperature heat pump compressor 41; another part of the refrigerant passes through the active jet reheat-increasing subcooling electronic expansion valve 45 and enters the active jet reheat-increasing subcooler 46. The active jet reheat-increasing water pump 52 pumps the hot water in the hot water storage tank 50 to exchange heat with the refrigerant entering the active jet reheat-increasing subcooler 46. The jet refrigerant absorbs the heat provided by the hot water and returns to the high-temperature heat pump compressor 41 through the active jet reheat-increasing injection pipe 47.

[0093] 6. Multi-unit heating + heat storage cycle

[0094] See the flow diagram for Figure 7 In the heating mode, the heat storage module works synchronously to store heat. The refrigerant discharged from the low-temperature heat pump compressor 1 is divided into two paths after passing through the oil separator 3. One path of refrigerant passes through the outdoor unit module and the indoor unit module and reaches the low-temperature heat pump liquid pipe stop valve 8. The other path of refrigerant passes through the heat storage module and converges to the low-temperature heat pump liquid pipe stop valve 8. The complete flow directions of the two refrigerants refer to the flow paths of the multi-unit heating cycle and the flow paths of the heat pump single heat storage cycle mentioned above.

[0095] 7. Defrost cycle

[0096] When entering the defrost cycle, the four-way valve 5 is reversed, the low-temperature heat pump enters the refrigeration operation mode, the high-temperature heat pump system and the heat storage module do not participate in defrosting, and keep the heating operation. During the defrosting process, conventional jet enthalpy is increased to increase the refrigerant circulation volume of the defrosting operation, increase the system low pressure, speed up the defrosting speed, improve the defrosting effect, and increase the compressor exhaust superheat during the defrosting process to avoid compressor damage caused by liquid return during the defrosting process. The specific cycle process is as follows:

[0097] Please refer to the flow diagram Figure 8The refrigerant discharged from the low-temperature heat pump compressor 1 passes through the d pipe of the four-way valve 5, the c pipe of the four-way valve 5, the outdoor heat exchanger 12, the low-temperature heat pump main electronic expansion valve 11, the conventional jet enthalpy increase subcooler 10, the high-pressure liquid storage tank 9, the low-temperature heat pump liquid pipe stop valve 8, the indoor unit, and then passes through the low-temperature heat pump gas pipe stop valve 7, the e pipe of the four-way valve 5, the s pipe of the four-way valve 5, and the gas-liquid separator 14 before returning to the low-temperature heat pump compressor 1. During the defrosting process, the conventional jet enthalpy increase subcooling electronic expansion valve 15 is opened, and a part of the refrigerant enters the subcooler 10 through the conventional jet enthalpy increase subcooling electronic expansion valve 15, exchanges heat with the refrigerant in the main liquid pipe passing through the subcooler 10, and then is injected into the intermediate pressure chamber of the low-temperature heat pump compressor 1 through the conventional jet enthalpy increase injection pipe 16.

[0098] A multifunctional heat pump control method based on cascade active jet enthalpy increase, such as Fig.10 As shown, it includes a multi-split cooling control step, a multi-split heating control step and a hot water control step, and the cooling operation control step, the heating operation control step or the hot water control step is executed based on the wire controller instruction.

[0099] The refrigeration operation control step comprises:

[0100] Step S1A: a preset refrigeration operation start condition is configured, and when the refrigeration operation start condition is met, refrigeration operation control is started;

[0101] Step S1B: a preset refrigeration operation shut-off condition is configured, and when the refrigeration operation shut-off condition is met, the refrigeration operation control is terminated.

[0102] In the cooling operation control step, the ambient temperature is high, and the heat storage module and the cascade active jet enthalpy increase heat pump water heater module do not participate in the work.

[0103] The heating operation control step comprises:

[0104] Step S2A: a preset heating operation start condition is configured. When the heating operation start condition is met, the heating operation control is turned on.

[0105] Step S2B: a preset heating operation shut-down condition is configured, and when the heating operation shut-down condition is met, the heating operation control is shut down.

[0106] The hot water production operation control step includes:

[0107] Step S3A: a preset start-up condition for producing thermal storage hot water is configured. When the start-up condition for producing thermal storage hot water is met, the control for producing thermal storage hot water is started;

[0108] Step S3B: a preset shutdown condition for producing thermal storage hot water is configured. When the shutdown condition for producing thermal storage hot water is met, the thermal storage hot water production operation control is shut down;

[0109] Step S4A: a preset cascade heat pump hot water operation start-up condition is configured, and when the cascade heat pump hot water operation start-up condition is met, the cascade heat pump hot water operation control is started;

[0110] Step S4B: a preset cascade heat pump hot water operation shut-down condition is configured, and when the cascade heat pump hot water operation shut-down condition is met, the cascade heat pump hot water operation control is shut down;

[0111] Step S5A: a preset cascade active jet enthalpy heat pump hot water operation start-up condition is configured, and when the cascade active jet enthalpy heat pump hot water operation start-up condition is met, the cascade active jet enthalpy heat pump hot water operation is started;

[0112] Step S5B: The preset cascade active jet enthalpy heat pump hot water operation shutdown condition and the heat pump hot water shutdown condition are configured. When the cascade active jet enthalpy heat pump hot water operation shutdown condition is met, the cascade active jet enthalpy heat pump hot water operation is shut down, and the cascade heat pump hot water operation control is performed. When the heat pump hot water shutdown condition is met, the cascade active jet enthalpy heat pump water heater module is shut down.

[0113] The method further comprises step S6A: configuring a preset defrost entry determination condition, and starting the defrost operation control when the defrost entry determination condition is met;

[0114] Step S6B: a preset defrost termination determination condition is configured, and when the defrost termination determination condition is met, the defrost operation control is turned off.

[0115] The following describes the control contents in detail according to the operation mode.

[0116] 1. Multi-unit refrigeration cycle operation mode

[0117] The indoor unit module adopts multi-split, and the startup, shutdown and operation of each multi-split fan tray indoor unit 21 are independently controlled. Each fan tray indoor unit 21 is connected to a wired controller and starts after receiving a "cooling" command.

[0118] 1.1 Refrigeration operation start conditions and control

[0119] The fan unit 21 is on, and the indoor unit start condition is judged. The cooling operation start condition is configured with a preset cooling temperature. When the return air temperature is detected to be greater than the sum of the preset cooling temperature and the return air temperature return difference threshold, the corresponding indoor unit electronic expansion valve 22 is opened, the fan of the fan unit is turned on, the low temperature heat pump compressor 1 starts to run, and the fan on the outdoor heat exchanger 12 is turned on.

[0120] 2.2 Refrigeration operation shutdown conditions and control

[0121] The cooling operation closing condition is specifically that when it is detected that the return air temperature is less than or equal to the difference between the preset cooling temperature and the return air temperature return difference threshold, the indoor electronic expansion valve 22 is closed.

[0122] When all the fan disc indoor units 21 stop, the outdoor unit stops running, and the fans on the low-temperature stage heat pump compressor 1 and the outdoor heat exchanger 12 stop.

[0123] 2. Multi-unit thermal cycle operation mode

[0124] 2.1 Heating operation start conditions and control

[0125] The fan disk indoor unit 21 is under the startup condition, and the indoor unit startup condition is determined. The indoor unit startup condition is configured with a preset heating temperature. When the return air temperature is detected to be less than the difference between the preset heating temperature and the return air temperature return difference threshold, the corresponding indoor unit electronic expansion valve 22 is opened, the fan disk indoor unit 21 is turned on, the low temperature heat pump compressor 1 starts to run, and the fan on the outdoor heat exchanger 12 is turned on.

[0126] 2.2 Heating operation shutdown conditions

[0127] The heating operation closing condition is specifically that when it is detected that the return air temperature is less than or equal to the sum of the preset heating temperature and the return air temperature return difference threshold, the indoor electronic expansion valve 22 is closed.

[0128] When all the fan disc indoor units 21 stop, the outdoor unit stops running, and the fans on the low-temperature stage heat pump compressor 1 and the outdoor heat exchanger 12 stop.

[0129] 3. Single heat storage operation mode:

[0130] 3.1 Conditions for starting the operation of thermal storage hot water production

[0131] In the system shutdown state, the thermal storage hot water production operation start condition is configured with a preset outdoor ambient temperature threshold and a water temperature setting target value. When the outdoor ambient temperature is detected to be lower than the preset ambient temperature threshold T ao,set1 And the duration reaches the preset duration, and it is detected that when the actual stored water temperature T tank,cur Lower than the water temperature setting target value T tank,setThe temperature difference ΔT from the preset first water storage temperature tank,set1 If the difference between the outdoor temperature and the setting temperature T is greater than the setting temperature T, the condition for starting the operation of hot water storage is met. ao,set1 ℃, for 30 seconds; and the current actual stored water temperature T tank,cur Lower than the water temperature setting target value T tank,set - Storage water temperature differential temperature ΔT tank,set1 , ΔT tank,set1 Set to 1°C, duration to 30 seconds, and heat storage operation starts.

[0132] 3.2 Control content

[0133] The operating frequency of the low-temperature heat pump compressor is set according to the target value of the stored water temperature T. tank,set Adjustment is performed when the actual stored water temperature T tank,cur Lower than the target value T of the stored water temperature tank,set - Storage water temperature differential temperature ΔT tank,set1 , the low temperature heat pump compressor increases the frequency of operation; when the actual storage water temperature T tank,cur Higher than the target value T of the stored water temperature tank,set + Storage water temperature differential temperature ΔT tank,set1 , the low temperature heat pump compressor reduces the frequency of operation, when the stored water temperature T tank,cur Between the target value of the hot water temperature T tank,set - Storage water temperature differential temperature ΔT tank,set1 and the target value of the stored water temperature T tank,set + Storage water temperature differential temperature ΔT tank,set1 In between, the low temperature stage heat pump compressor maintains frequency operation.

[0134] 3.3 Shutdown conditions for producing thermal storage hot water

[0135] The thermal storage hot water production operation shutdown condition is configured with a preset second thermal storage hot water temperature return difference temperature. When the actual thermal storage hot water temperature T tank,cur Higher than the water temperature setting target value T tank,set The temperature difference with the second water storage water temperature ΔT tank,set2 When the actual storage water temperature T tank,cur Higher than the target value T of the stored water temperature tank,set +ΔT tank,set2 When the heat storage stops, the low temperature stage heat pump compressor stops running.

[0136] 4. Conventional heat pump hot water operation mode:

[0137] 4.1 Conditions for starting cascade heat pump hot water operation

[0138] The cascade high-temperature heat pump is connected to a wire controller, and the wire controller receives a hot water start-up command. The cascade heat pump hot water operation start-up condition is configured with a preset return water temperature target value and a preset first return water return temperature difference. When the detected return water temperature is less than the difference between the return water temperature target value and the first return water return temperature difference, and the duration reaches a preset time, it is considered that the cascade heat pump hot water operation start-up condition is met. For example: the cascade high-temperature heat pump is connected to a wire controller, and the wire controller issues a start-up command. When the return water temperature sensor 60 detects a return water temperature T w,in,cur Less than the return water temperature target value T w,in,set -ΔT w,in,set1 ℃, ΔT w,in,set1 Set to 1°C for 30 seconds, the low-temperature heat pump starts running and the high-temperature heat pump starts at the same time.

[0139] 4.2 Control content

[0140] The low temperature heat pump is set according to a certain condensation temperature target value T con,set To adjust the low temperature heat pump compressor frequency, when the actual operating condensing temperature T con,cur Lower than the condensation temperature target value T con,set - Hysteresis value ΔT con,set , the low temperature heat pump compressor increases the frequency. When the actual operating condensing temperature T con,cur Higher than T con,setr + Hysteresis value ΔT con,set , the low temperature heat pump compressor reduces the frequency, when the actual condensing temperature is between the condensing temperature target value T con,tset - Hysteresis value ΔT con,set and condensation temperature target value T con,set + Hysteresis value ΔT con,set The frequency of the low temperature stage heat pump compressor remains unchanged.

[0141] The high temperature heat pump is set according to a certain return water temperature target value T w,in,set To adjust the frequency of the high-temperature heat pump compressor, when the actual operating return water temperature T w,in,set Lower than the return water temperature target value T w,in,set - Hysteresis value ΔT w,in,set1 , the high temperature heat pump compressor increases the frequency. When the actual operating return water temperature T w,in,cur Higher than the return water temperature target value T w,in,set + Hysteresis value ΔT w,in,set1 , the high temperature heat pump compressor reduces the frequency, when the actual return water temperature T w,in,cur Between the return water temperature target value T w,in,set - Hysteresis value ΔT w,in,set1 and return water temperature target value T w,in,set + Hysteresis value ΔT w,in,set1The frequency of the high temperature stage heat pump compressor remains unchanged.

[0142] 4.3 Shutdown conditions for cascade heat pump hot water operation

[0143] The cascade heat pump hot water operation shutdown condition is configured with a preset second return water differential temperature. When the detected return water temperature is greater than the sum of the return water temperature target value and the preset second return water differential temperature, and the duration reaches a preset time, the cascade heat pump hot water operation shutdown condition is considered to be met. That is: when the actual operating return water temperature T w,in,cur Higher than the return water temperature target value T w,in,set +ΔT w,in,set2 , and lasts for a preset time, such as ΔT w,in,set2 Set to 1°C for a preset duration of 30 seconds, the high-temperature heat pump stops running and the high-temperature heat pump compressor stops; at the same time, the low-temperature heat pump stops running and the low-temperature heat pump compressor stops.

[0144] 5. Cascade active jet enthalpy-increasing heat pump hot water operation mode:

[0145] 5.1 Conditions for hot water operation of cascade active jet enthalpy heat pump

[0146] Based on the conventional heat pump hot water operation mode, it is judged that

[0147] The following conditions must be met at the same time:

[0148] 1) The above-mentioned cascade heat pump startup and operation conditions are met, that is,

[0149] The wire controller sends a power-on command. When the return water temperature sensor 60 detects the return water temperature T w,in,cur Less than the return water temperature target value T w,in,set - Hysteresis value ΔT w,in,set1 , for a preset duration, such as ΔT w,in,set1 Set to 1°C, and keep for 30 seconds, the low-temperature heat pump starts running, and the high-temperature heat pump starts at the same time.

[0150] 2) Outdoor ambient temperature T ao Lower than the set second ambient temperature threshold T ao,set2 , and the duration reaches the preset duration.

[0151] 3) The cascade heat pump is started and runs for a preset time, such as 5 minutes. The exhaust temperature and exhaust superheat are detected to ensure that the exhaust superheat ΔT d,cur Greater than the set first exhaust superheat target value ΔT d,set1The exhaust gas superheat is defined as the saturation temperature corresponding to the exhaust gas temperature detected by the exhaust gas temperature sensor 62 of the high temperature stage heat pump compressor 41 minus the high pressure detected by the high pressure pressure sensor 61 .

[0152] 4) Simultaneously detect the temperature of the thermal storage hot water T tank,cur If the thermal storage hot water temperature T is detected tank,cur >The temperature T detected by the liquid pipe temperature sensor 58 liq + Thermal storage hot water temperature hysteresis threshold ΔT tank,liq [Set value], and the duration reaches the preset time, the active jet enthalpy increase is turned on, and the corresponding source jet enthalpy increase subcooling electronic expansion valve 45 is opened, and the reference opening is V open1 [Set value], using the hot water in the water storage tank as the jet enthalpy heat source, the active jet enthalpy water pump 52 is turned on, and the water flow rate is constant at Y m 3 / h

set value

[0153] 5.2 Control content

[0154] The low temperature heat pump is set according to a certain condensation temperature target value T con,set To adjust the compressor frequency, when the actual operating condensing temperature T con,cur Lower than the condensation temperature target value T con,set - Hysteresis value ΔT con,set , the compressor increases the frequency. When the actual operating condensing temperature T con,cur Higher than T con,setr + Hysteresis value ΔT con,set , the compressor reduces the frequency. When the actual condensing temperature is between the condensing temperature target value T con,setr - Hysteresis value ΔT con,set and condensation temperature target value T con,setr + Hysteresis value ΔT con,set The compressor frequency remains unchanged.

[0155] The high temperature heat pump is set according to a certain return water temperature target value T w,in,set To adjust the compressor frequency, when the actual operating return water temperature T is detected w,in,cur Lower than the return water temperature target value T w,in,set - Hysteresis value ΔT w,in,set1 , the compressor increases the frequency. When the actual operating return water temperature T w,in,cur Higher than the return water temperature target value T w,in,set + Hysteresis value ΔT w,in,set1 , the compressor reduces the frequency, when the actual return water temperature T w,in,cur Between the return water temperature target value T w,in,set - Hysteresis value ΔT w,in,set1 and return water temperature target value T w,in,set + Hysteresis value ΔT w,in,set1When the actual operating return water temperature T w,in,cur Higher than the return water temperature target value T w,in,set +ΔT w,in,set2 , and it lasts for 30 seconds, the high-temperature heat pump stops running and the high-temperature compressor stops; at the same time, the low-temperature heat pump stops running and the low-temperature heat pump compressor stops.

[0156] When the active jet reheating start-up conditions are met, the active jet reheating water pump 52 is started and runs to pump hot water into the active jet reheating subcooler 46 according to the set flow rate.

[0157] The source jet enthalpy-increasing subcooling electronic expansion valve 45 is opened to the reference opening, and the initial opening is V open .

[0158] After 3 minutes, when the active jet enthalpy-increasing hot water inlet temperature T w,inj,in ≥Active jet enthalpy increase refrigerant outlet temperature T ref,inj,out + Hysteresis value setting value ΔT w-in,ref-out1 , and the outlet temperature of hot water with active jet enthalpy increase is T w,inj,out ≥Active jet enthalpy increase refrigerant inlet temperature T ref,inj,in + Hysteresis setting value ΔT w-out,ref-in1 , the opening of the subcooling electronic expansion valve with active jet enthalpy increase is adjusted.

[0159] According to the refrigerant injection superheat target value ΔT ref,inj,set Control and define the injection superheat ΔT ref,inj is the outlet temperature of the active jet enthalpy refrigerant T ref , inj,out Active jet enthalpy increase refrigerant inlet temperature T ref,inj,in When the actual injection superheat ΔT ref,inj_cur > Injection superheat target value ΔT ref,inj , set + Refrigerant injection hysteresis setting value ΔT ref,inj , the opening degree of the active jet enthalpy-increasing subcooling electronic expansion valve 45 is controlled to be widened; when the actual jet superheat ΔT ref,inj _cur<ΔT ref,inj _ set -Refrigerant injection differential setting value ΔT ref,inj , the opening degree of the active jet enthalpy-increasing subcooling electronic expansion valve 45 is controlled to be small; when ΔT ref,inj , set -Refrigerant injection differential setting value ΔT ref,inj ≤Actual injection superheat ΔT ref,inj_cur ≤ Injection superheat target value ΔT ref,inj _ set + Refrigerant injection hysteresis setting value ΔTref,inj, , the active jet enthalpy increase subcooling electronic expansion valve maintains the current opening unchanged.

[0160] 5.3 Shutdown conditions for hot water operation of cascade active jet enthalpy heat pump

[0161] When one of the following conditions is met, the active jet reheating stops, the active jet reheating water pump 52 stops running, and the active jet reheating subcooling electronic expansion valve 45 is closed.

[0162] 1) Outdoor ambient temperature T ao Higher than the set third ambient temperature threshold T ao,set3

[0163] 2) Exhaust superheat ΔT d,cur Less than the designed second exhaust gas superheat target value ΔT d,set2

[0164] 3) When the active jet enthalpy increase hot water inlet temperature T w,inj,in ≤Active jet enthalpy increase refrigerant outlet temperature T ref,inj,out + Hysteresis value setting value ΔT w-in,ref-out2 , or active jet enthalpy increase hot water outlet temperature T w,inj,out ≤Active jet enthalpy increase refrigerant inlet temperature T ref,inj,in + Hysteresis setting value ΔT w-out,ref-in2 .

[0165] When one of the above conditions is met, the active jet reheating stops, the active jet reheating water pump 52 stops running, the source jet reheating subcooling electronic expansion valve 45 is closed, and only the cascade heat pump hot water operation is performed.

[0166] When the actual operating return water temperature T w,in,cur Higher than the return water temperature target value T w,in,set + set hysteresis value ΔT w,in,set2 , the high-temperature heat pump stops running and the high-temperature compressor stops; at the same time, the low-temperature heat pump stops running and the low-temperature heat pump compressor stops.

[0167] 6. Multi-unit heating + heat storage operation mode:

[0168] 6.1 Enabling conditions

[0169] At the same time, the start-up conditions for the multi-unit heating operation and the start-up conditions for the production of thermal storage hot water are met. For specific reference, refer to the start-up conditions in 2.1 and 3.1.

[0170] 6.2 Control content

[0171] The multi-unit heat generation operation and the thermal storage hot water production operation are controlled independently, referring to the control contents of 2.2 and 3.2 respectively.

[0172] 6.3 Closing conditions

[0173] The shutdown of the multi-split heating operation and the thermal storage hot water production operation are judged independently, referring to the shutdown conditions of 2.3 and 3.3 respectively. Among them, when only the shutdown condition of 2.3 is met, the multi-split heating operation is stopped, the indoor unit electronic expansion valve 22 is closed, and the thermal storage module continues to produce thermal storage hot water; when only the shutdown condition of 3.3 is met, the thermal storage hot water operation of the thermal storage module is stopped, and the multi-split unit maintains heating operation. When the shutdown conditions of 2.3 and 3.3 are met at the same time, both the indoor unit module and the thermal storage module stop working, and the outdoor unit is shut down.

[0174] 7. Defrost operation mode:

[0175] The defrosting entry judgment conditions, defrosting end judgment conditions and control logic have been given in Patent ZL201910300817.3, and will not be repeated again. The present invention provides the control logic of each component of the defrosting process.

[0176] When entering the defrost cycle, the high-temperature heat pump maintains heating operation, the high-temperature heat pump compressor 41 is turned on, and the operation is controlled according to the set return water temperature. The four-way valve 5 is reversed, and the low-temperature heat pump enters the cooling operation mode. The high-temperature heat pump system does not participate in defrosting and maintains heating operation. The low-temperature heat pump uses the stored heat to perform heat storage defrosting. Conventional jet enthalpy increase is performed during the defrosting process. The conventional jet enthalpy increase subcooling electronic expansion valve 15 is opened to the preset opening, increasing the refrigerant circulation volume of the defrosting operation, increasing the system low pressure, accelerating the defrosting speed, and improving the defrosting effect. In addition, the compressor exhaust superheat can be increased during the defrosting process to avoid compressor damage caused by liquid return during the defrosting process.

[0177] At the same time, the solenoid valve 32 is opened, and the thermal storage hot water pump 51 is running to perform thermal storage defrosting. The refrigerant in the defrosting cycle absorbs the heat of the thermal storage hot water, which is conducive to rapid defrosting.

[0178] The above are only preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A multifunctional heat pump based on cascade active jet enthalpy increase, characterized by: Including outdoor unit module, indoor unit module, cascade active jet enthalpy heat pump water heater module and heat storage module, The cascade active jet enthalpy-increasing heat pump water heater module and the heat storage module are respectively connected to the outdoor unit module and the indoor unit module through pipelines; The outdoor unit module and the indoor unit module are capable of performing heating operation and cooling operation; The cascade active jet enthalpy heat pump water heater module comprises a cascade heat exchanger (36), a high-temperature heat pump compressor (41), a high-temperature heat pump plate heat exchanger (43), an active jet enthalpy subcooling electronic expansion valve (45), and an active jet enthalpy subcooler (46), wherein the cascade heat exchanger (36) and the outdoor unit module participate in a low-temperature heat pump cycle, the cascade heat exchanger (36), the high-temperature heat pump compressor (41), and the high-temperature heat pump plate heat exchanger (43) participate in a high-temperature heat pump cycle, and the high-temperature heat pump plate heat exchanger (43) is used to perform heat exchange with the load side to produce hot water. The heat storage module is used to store heat as an external heat source when the outdoor unit module is in heating operation and cooling operation, and the external heat source is used to exchange heat with the refrigerant flowing through the active jet enthalpy increase subcooler (46).

2. The multifunctional heat pump based on cascade active jet enthalpy increase according to claim 1, characterized in that: The cascade active jet enthalpy-increasing heat pump water heater module comprises a cascade heat pump solenoid valve (35), a high-temperature heat pump main electronic expansion valve (44) and a high-temperature heat pump water pump (49); the high-temperature heat pump exhaust pipe (42) of the high-temperature heat pump compressor (41) is connected to the inlet pipe of the high-temperature heat pump plate heat exchanger (43); the outlet pipe of the high-temperature heat pump plate heat exchanger (43) is connected to the high-temperature heat pump main electronic expansion valve (44) and the heat exchange inlet pipe of the cascade heat exchanger (36) in sequence; the heat exchange outlet pipe of the cascade heat exchanger (36) is connected to the high-temperature compressor return pipe of the high-temperature heat pump compressor (41); the high-temperature heat pump plate heat exchanger (43) is connected to the load side (48) through a pipeline; the high-temperature heat pump water pump (49) pumps hot water to circulate in the high-temperature heat pump plate heat exchanger (43) and the load side (48); One end of the active jet enthalpy increase and subcooling electronic expansion valve (45) is connected to the outlet pipe of the high-temperature heat pump plate heat exchanger (43), and the other end of the active jet enthalpy increase and subcooling electronic expansion valve (45) is connected to the active jet enthalpy increase and inlet pipe of the active jet enthalpy increase and subcooler (46). The active jet enthalpy increase and injection pipe (47) of the active jet enthalpy increase and subcooler (46) is connected to the jet enthalpy increase and injection port of the high-temperature heat pump compressor (41), and the active jet enthalpy increase and subcooler (46) is connected to the heat storage module through a pipeline; The heat storage module comprises a heat storage module solenoid valve (32), a heat storage module plate heat exchanger (33), a heat storage module electronic expansion valve (34), a heat storage water tank (50), a heat storage hot water pump (51) and an active jet enthalpy increasing water pump (52); the heat storage hot water pump (51) pumps hot water to circulate between the heat storage module plate heat exchanger (33) and the heat storage water tank (50); and the active jet enthalpy increasing water pump (52) pumps hot water to circulate between the heat storage water tank (50) and the active jet enthalpy increasing subcooler (46).

3. The multifunctional heat pump based on cascade active jet enthalpy increase according to claim 1, characterized in that: The heat storage tank also includes a temperature detection module, the temperature detection module including a water temperature sensor (53) for the hot water storage tank, a jet enthalpy water inlet temperature sensor (54), a jet enthalpy water outlet temperature sensor (55), a jet enthalpy refrigerant inlet temperature sensor (56), a jet enthalpy refrigerant outlet temperature sensor (57), a liquid pipe temperature sensor (58), a hot water outlet temperature sensor (59) generated by the heat pump, a return water temperature sensor (60), a fan coil liquid pipe temperature sensor (23), a fan coil air pipe temperature sensor (24) and a fan coil return air temperature sensor (25). The hot water storage tank water temperature sensor (53) is used to detect the actual hot water temperature T in the hot water storage tank (50). tank,cur The jet enthalpy water inlet temperature sensor (54) is used to detect the active jet enthalpy hot water inlet temperature T w,inj,in The jet enthalpy increased water outlet temperature sensor (55) is used to detect the active jet enthalpy increased hot water outlet temperature T w,inj,out The jet enthalpy refrigerant inlet temperature sensor (56) is used to detect the active jet enthalpy refrigerant inlet temperature T ref,inj,in The jet enthalpy refrigerant outlet temperature sensor (57) is used to detect the active jet enthalpy refrigerant outlet temperature T ref,inj,out The liquid pipe temperature sensor (58) is used to detect the liquid pipe temperature T liq The return water temperature sensor (60) is used to detect the return water temperature T w,in,cur The fan disk return air temperature sensor (25) is used to detect the return air temperature of the fan disk unit (21), the fan disk liquid pipe temperature sensor (23) is used to detect the liquid pipe temperature of the fan disk unit, and the fan disk air pipe temperature sensor (24) is used to detect the air pipe temperature of the fan disk unit.

4. A multifunctional heat pump control method based on cascade active jet enthalpy increase, applied to a multifunctional heat pump based on cascade active jet enthalpy increase as claimed in any one of claims 1 to 3, characterized in that: It includes a cooling operation control step, a heating operation control step and a hot water operation control step, and the cooling operation control step, the heating operation control step or the hot water operation control step is executed based on the command of the wire controller; The hot water production operation control step includes: Step S3A: a preset start-up condition for producing thermal storage hot water is configured. When the start-up condition for producing thermal storage hot water is met, the control for producing thermal storage hot water is started; Step S3B: a preset shutdown condition for producing thermal storage hot water is configured. When the shutdown condition for producing thermal storage hot water is met, the thermal storage hot water production operation control is shut down; Step S4A: a preset cascade heat pump hot water operation start-up condition is configured, and when the cascade heat pump hot water operation start-up condition is met, the cascade heat pump hot water operation control is started; Step S4B: a preset cascade heat pump hot water operation shut-down condition is configured, and when the cascade heat pump hot water operation shut-down condition is met, the cascade heat pump hot water operation control is shut down; Step S5A: a preset cascade active jet enthalpy heat pump hot water operation start-up condition is configured, and when the cascade active jet enthalpy heat pump hot water operation start-up condition is met, the cascade active jet enthalpy heat pump hot water operation is started; Step S5B: The preset cascade active jet enthalpy heat pump hot water operation shutdown condition and the heat pump hot water shutdown condition are configured. When the cascade active jet enthalpy heat pump hot water operation shutdown condition is met, the cascade active jet enthalpy heat pump hot water operation is shut down, and the cascade heat pump hot water operation control is performed. When the heat pump hot water shutdown condition is met, the cascade active jet enthalpy heat pump water heater module is shut down.

5. The multifunctional heat pump control method with cascade active jet enthalpy increase according to claim 4 is characterized in that: The refrigeration operation control step comprises: Step S1A: a preset cooling operation start condition is configured. When the cooling operation start condition is met, the cooling operation control is turned on. Step S1B: a preset refrigeration operation shut-off condition is configured, and when the refrigeration operation shut-off condition is met, refrigeration operation control is terminated; In step S1A, the cooling operation start condition is specifically that the return air temperature is detected to be greater than the sum of the preset cooling temperature and the return air temperature return difference threshold. In step S1B, the cooling operation shut-down condition is specifically that the return air temperature is detected to be less than or equal to the difference between the preset cooling temperature and the return air temperature return difference threshold.

6. The multifunctional heat pump control method with cascade active jet enthalpy increase according to claim 4 is characterized in that: The heating operation control step comprises: Step S2A: a preset heating operation start condition is configured. When the heating operation start condition is met, the heating operation control is turned on. Step S2B: a preset heating operation shut-down condition is configured, and when the heating operation shut-down condition is met, the heating operation control is shut down; In step S2A, the heating operation start condition is specifically that the return air temperature is detected to be less than the difference between the preset heating temperature and the return air temperature return difference threshold. In step S2B, the heating operation shut-down condition is specifically that the return air temperature is detected to be greater than or equal to the sum of a preset heating temperature and a return air temperature return difference threshold.

7. The multifunctional heat pump control method with cascade active jet enthalpy increase according to claim 4 is characterized in that: In step S3A, the thermal storage hot water production operation start condition is configured with a preset first ambient temperature threshold and a water temperature setting target value. When it is detected that the outdoor ambient temperature is lower than the preset first ambient temperature threshold and the duration reaches the preset duration, and when it is detected that the actual stored water temperature is lower than the difference between the water temperature setting target value and the preset first stored water temperature return difference temperature and the duration reaches the preset duration, it is considered that the thermal storage hot water production operation start condition is met; In step S3B, the thermal storage hot water production operation shut-down condition is configured with a preset second thermal storage water temperature hysteresis temperature. When it is detected that the actual thermal storage hot water temperature is higher than the sum of the water temperature setting target value and the second thermal storage water temperature hysteresis temperature, and the duration reaches a preset time, the thermal storage hot water production operation shut-down condition is deemed to be met.

8. The multifunctional heat pump control method with cascade active jet enthalpy increase according to claim 4 is characterized in that: In step S4A, the cascade heat pump hot water operation start-up condition is configured with a preset return water temperature target value and a preset first return water return temperature difference. When the detected return water temperature is less than the difference between the return water temperature target value and the first return water return temperature difference, and the duration reaches a preset time, the cascade heat pump hot water operation start-up condition is deemed to be met; In step S4B, the cascade heat pump hot water operation shut-down condition is configured with a preset second return water return temperature difference. When the detected return water temperature is greater than the sum of the return water temperature target value and the preset second return water return temperature difference, and the duration reaches a preset time, the cascade heat pump hot water operation shut-down condition is deemed to be met.

9. The multifunctional heat pump control method with cascade active jet enthalpy increase according to claim 4, characterized in that: The exhaust gas superheat is defined as the exhaust gas temperature detected by the exhaust gas temperature sensor (62) of the high temperature stage heat pump compressor (41) minus the saturation temperature corresponding to the high pressure detected by the high pressure pressure sensor (61); In step S5A, the cascade active jet enthalpy heat pump hot water operation start-up condition is configured with a preset second ambient temperature threshold, a first exhaust superheat target value, and a thermal storage hot water temperature hysteresis setting threshold. When it is detected that the outdoor ambient temperature is lower than the second ambient temperature threshold, and the cascade heat pump is turned on and runs for more than a preset running time, it is detected that the exhaust superheat is greater than the preset first exhaust superheat target value, and it is detected that the thermal storage hot water temperature is greater than the sum of the liquid pipe temperature and the thermal storage hot water temperature hysteresis setting threshold and the duration exceeds a preset time, it is deemed that the cascade active jet enthalpy heat pump hot water operation start-up condition is met; In step S5B, the cascade active jet enthalpy heat pump hot water operation shut-down condition is configured with a third ambient temperature threshold, a second exhaust superheat target value and a hysteresis setting value. When it is detected that the outdoor ambient temperature is higher than the third ambient temperature threshold, or the exhaust superheat is less than the preset second exhaust superheat target value, or when the active jet enthalpy hot water inlet temperature is less than or equal to the sum of the active jet enthalpy refrigerant outlet temperature and the hysteresis setting value, or the active jet enthalpy hot water outlet temperature is less than or equal to the sum of the active jet enthalpy refrigerant inlet temperature and the hysteresis setting value, the cascade active jet enthalpy heat pump hot water operation shut-down condition is deemed to be met; In step S5B, the heat pump hot water shutdown condition is configured with a return water temperature target value and a return water temperature hysteresis threshold. When the return water temperature is detected to be higher than the sum of the return water temperature target value and the return water temperature hysteresis threshold, the heat pump hot water shutdown condition is deemed to be met.

10. The multifunctional heat pump control method with cascade active jet enthalpy increase according to claim 4, characterized in that: The method further comprises step S6A: configuring a preset defrost entry determination condition, and starting the defrost operation control when the defrost entry determination condition is met; Step S6B: a preset defrost termination determination condition is configured, and when the defrost termination determination condition is met, the defrost operation control is turned off.

Images