Double-effect jet type heat pump system and control method

Abstract

The invention relates to a double-effect jet type heat pump system and a control method.The system comprises a generator, a first ejector, a second ejector, a condenser, a liquid storage tank and an evaporator, two ports of the primary side of the generator are connected with a heat source, and a secondary side outlet of the generator is connected with a main flow inlet of the first ejector; an outlet of the first ejector is connected with a main flow inlet of the second ejector, an outlet of the second ejector is connected with a primary side inlet of the condenser and a secondary flow inlet of the first ejector, a primary side outlet of the condenser is connected with a liquid storage tank and a secondary side inlet of the evaporator, and two ports of the secondary side of the condenser are connected with the heat supply tail end. The liquid storage tank is connected with a secondary side inlet of the generator, a secondary side outlet of the evaporator is connected with a secondary flow inlet of the second ejector, two ports of the primary side of the evaporator are connected with a heat source, and the device has the advantages of being simple in structure, convenient to operate and control, good in stability and high in safety; the method has the advantages of simple process, safety and reliability.

Description

Technical Field

[0001] The present invention relates to a heat pump system, in particular to a double-effect ejector heat pump system with ejectors in series and a control method for the system. Background Art

[0002] With the development of economy and society, the significance of energy conservation has become increasingly prominent. During the process of industrial development, a large amount of high-temperature wastewater and waste gas (low-grade heat energy) are often directly discharged into the environment without energy recovery and utilization, which not only causes energy waste but also causes certain thermal pollution to the environment. As an air conditioner or heating device, a heat pump has certain technical advantages in the recovery and utilization of industrial waste heat (high-temperature wastewater or waste gas) and can generate good economic benefits. Compared with traditional heat pumps, an ejector heat pump uses an ejector to replace the compressor and has the advantages of simple structure, reliable operation, high thermal efficiency, and energy conservation. However, when an ejector heat pump works, it is driven by a high-level heat source and supplies heat by recovering the heat of a low-level heat source. Due to the large temperature difference between the high-level heat source and the low-level heat source, the expansion ratio (mainstream fluid pressure / secondary fluid pressure) and shock loss of the ejector heat pump are relatively large, which affects the ejector efficiency and the COP of the overall system. Summary of the Invention

[0003] The object of the present invention is to provide a double-effect ejector heat pump system and a control method. The system has the advantages of simple structure, convenient operation, good stability, and high safety; the method has the advantages of simple process, safety, and reliability.

[0004] To solve the above problems existing in the prior art, the present invention provides a double-effect ejector heat pump system, including a generator, a first ejector, a second ejector, a condenser, a liquid storage tank, and an evaporator. The two ports at the primary side of the generator are respectively connected to a heat source through heat exchange pipelines to form a first heat exchange loop. The outlet of the secondary side of the generator is connected to the mainstream inlet of the first ejector through a first working medium pipeline. The outlet of the first ejector is connected to the mainstream inlet of the second ejector through a second working medium pipeline. The outlet of the second ejector is connected to the inlet of the primary side of the condenser through a third working medium pipeline. The third working medium pipeline is connected to the secondary flow inlet of the first ejector through a fourth working medium pipeline. The outlet of the primary side of the condenser is connected to the liquid storage tank through a fifth working medium pipeline. The two ports at the secondary side of the condenser are respectively connected to a heat supply end through heat exchange pipelines to form a heat supply loop. The liquid storage tank is connected to the inlet of the secondary side of the generator through a sixth working medium pipeline. The fifth working medium pipeline is connected to the inlet of the secondary side of the evaporator through a seventh working medium pipeline. The outlet of the secondary side of the evaporator is connected to the secondary flow inlet of the second ejector through an eighth working medium pipeline. The two ports at the primary side of the evaporator are respectively connected to a heat source through heat exchange pipelines to form a second heat exchange loop. A working medium pump is provided on the sixth working medium pipeline, and a throttle valve is provided on the seventh working medium pipeline.

[0005] Optionally, a double-effect ejector heat pump system of the present invention further includes a heat exchanger, and both ends of the primary side of the heat exchanger are connected in series in the second refrigerant pipeline, and both ends of the secondary side of the heat exchanger are connected in series in the sixth refrigerant pipeline.

[0006] Furthermore, in a double-effect ejector heat pump system of the present invention, the refrigerant pump is arranged on the sixth refrigerant pipeline between the heat exchanger and the liquid storage tank.

[0007] Optionally, a double-effect ejector heat pump system of the present invention further includes a heat exchanger, and both ends of the primary side of the heat exchanger are connected in series in the third refrigerant pipeline, and both ends of the secondary side of the heat exchanger are connected in series in the sixth refrigerant pipeline.

[0008] Furthermore, in a double-effect ejector heat pump system of the present invention, the refrigerant pump is arranged on the sixth refrigerant pipeline between the heat exchanger and the liquid storage tank.

[0009] Furthermore, in a double-effect ejector heat pump system of the present invention, the connection point between the fourth refrigerant pipeline and the third refrigerant pipeline is located between the heat exchanger and the condenser.

[0010] Optionally, a double-effect ejector heat pump system of the present invention further includes a heat exchanger, and both ends of the primary side of the heat exchanger are connected in series in the eighth refrigerant pipeline, and both ends of the secondary side of the heat exchanger are connected in series in the seventh refrigerant pipeline.

[0011] Furthermore, in a double-effect ejector heat pump system of the present invention, the throttle valve is arranged on the seventh refrigerant pipeline between the heat exchanger and the evaporator.

[0012] Furthermore, in a double-effect ejector heat pump system of the present invention, temperature sensors T 1 and T 2 are respectively arranged at both ends of the primary side of the generator, temperature sensors T 3 and T 4 are respectively arranged at both ends of the primary side of the evaporator, temperature sensors T 5 and T 6 are respectively arranged at both ends of the secondary side of the condenser, a temperature sensor T 7 and a pressure sensor P 1 are arranged at the main flow inlet of the first ejector, a temperature sensor T 8 and a pressure sensor P 2 are arranged at the outlet of the second ejector.

[0013] Based on the same concept, the present invention also provides a control method for a double-effect ejector heat pump system, including the following steps:

[0014] S1. Start the system, and the fluids in the first heat exchange circuit, the second heat exchange circuit, the heating circuit, the primary heat pump circuit, and the secondary heat pump circuit circulate respectively. Among them, the fluids in the first heat exchange circuit and the second heat exchange circuit are high-temperature industrial wastewater or waste gas, referred to as high-temperature fluids for short; the fluid in the heating circuit is water or antifreeze, referred to as heating fluid for short; the fluids in the primary heat pump circuit and the secondary heat pump circuit are refrigerants. The primary heat pump circuit is formed by connecting a generator, a first ejector, a second ejector, a condenser, and a liquid storage tank in sequence end to end; the secondary heat pump circuit is formed by connecting a second ejector, a condenser, and an evaporator in sequence end to end.

[0015] S2. The high-temperature fluids transfer heat to the refrigerants in the generator and the evaporator respectively. The refrigerants transfer heat to the heating fluid in the condenser, and the heating fluid transfers heat to the heating terminal.

[0016] S3. The high-pressure refrigerant saturated fluid entering the generator absorbs heat and turns into high-pressure refrigerant vapor. The high-pressure refrigerant vapor is introduced into the first ejector and mixed with the medium-pressure refrigerant vapor from the outlet of the second ejector. The refrigerant vapor at the outlet of the first ejector is introduced into the second ejector and mixed with the low-pressure refrigerant vapor from the evaporator. Part of the medium-pressure refrigerant vapor at the outlet of the second ejector enters the condenser, and part is introduced into the first ejector. The medium-pressure refrigerant vapor entering the condenser releases heat and turns into medium-pressure refrigerant saturated liquid. Part of the medium-pressure refrigerant saturated liquid enters the liquid storage tank and is pumped up by a working fluid pump and then enters the generator. Part of it passes through a throttle valve to reduce the pressure and becomes a refrigerant gas-liquid two-phase fluid and enters the evaporator. The refrigerant gas-liquid two-phase fluid entering the evaporator absorbs heat and turns into low-pressure refrigerant vapor and is introduced into the second ejector.

[0017] Compared with the prior art, a dual-effect ejector heat pump system and a control method thereof according to the present invention have the following advantages: By providing a generator, a first ejector, a second ejector, a condenser, a liquid storage tank and an evaporator, both ports at the primary side of the generator are connected to a heat source through heat exchange pipelines to form a first heat exchange loop. The outlet at the secondary side of the generator is connected to the main stream inlet of the first ejector through a first working medium pipeline. The outlet of the first ejector is connected to the main stream inlet of the second ejector through a second working medium pipeline. The outlet of the second ejector is connected to the inlet at the primary side of the condenser through a third working medium pipeline. The third working medium pipeline is connected to the secondary flow inlet of the first ejector through a fourth working medium pipeline. The outlet at the primary side of the condenser is connected to the liquid storage tank through a fifth working medium pipeline. Both ports at the secondary side of the condenser are connected to a heat supply end through heat exchange pipelines to form a heat supply loop. The liquid storage tank is connected to the inlet at the secondary side of the generator through a sixth working medium pipeline. The fifth working medium pipeline is connected to the inlet at the secondary side of the evaporator through a seventh working medium pipeline. The outlet at the secondary side of the evaporator is connected to the secondary flow inlet of the second ejector through an eighth working medium pipeline. Both ports at the primary side of the evaporator are connected to a heat source through heat exchange pipelines to form a second heat exchange loop. Among them, a working medium pump is provided on the sixth working medium pipeline, and a throttle valve is provided on the seventh working medium pipeline. Thus, a dual-effect ejector heat pump system with a simple structure, convenient operation, good stability and high safety is formed. In practical applications, after the system is started, the fluids in the first heat exchange loop, the second heat exchange loop, the heat supply loop and the heat pump loop circulate respectively. Among them, the fluids in the first heat exchange loop and the second heat exchange loop are high-temperature industrial wastewater or waste gas, simply referred to as high-temperature fluids. The fluid in the heat supply loop is water or antifreeze, simply referred to as heat supply fluid. The fluid in the heat pump loop is a refrigerant. The high-temperature fluids transfer heat to the refrigerant in the generator and the evaporator respectively. The refrigerant transfers heat to the heat supply fluid in the condenser. The heat supply fluid transfers heat to the heat supply end. The high-pressure refrigerant saturated fluid entering the generator absorbs heat and is transformed into high-pressure refrigerant vapor. The high-pressure refrigerant vapor is introduced into the first ejector and mixed with the medium-pressure refrigerant vapor from the outlet of the second ejector. The refrigerant vapor at the outlet of the first ejector is introduced into the second ejector and mixed with the low-pressure refrigerant vapor from the evaporator. A part of the medium-pressure refrigerant vapor at the outlet of the second ejector enters the condenser, and a part is introduced into the first ejector. The medium-pressure refrigerant vapor entering the condenser releases heat and is transformed into medium-pressure refrigerant saturated liquid. A part of the medium-pressure refrigerant saturated liquid enters the liquid storage tank and is pumped to increase the pressure by the working medium pump and then enters the generator. A part is throttled and depressurized by the throttle valve to become a refrigerant gas-liquid two-phase fluid and enters the evaporator. The refrigerant gas-liquid two-phase fluid entering the evaporator absorbs heat and is transformed into low-pressure refrigerant vapor and is introduced into the second ejector.By arranging two ejectors (the first ejector and the second ejector) in series, compared with the existing ejector-type heat pump system, the present invention reduces the expansion ratio of a single ejector, decreases the internal loss of the ejector, realizes the cascaded utilization of energy, improves the ejector efficiency, and uses the outlet fluid of the second-effect ejector (the second ejector) to be entrained by the first-effect ejector (the first ejector), realizing the recycling of heat and improving the overall COP of the system. The heat pump system control method provided by the present invention has the advantages of simple process, safety and reliability.

[0018] The following further elaborates on a dual-effect ejector-type heat pump system and a control method thereof according to the present invention with reference to the specific embodiments shown in the drawings. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of the first embodiment of a dual-effect ejector-type heat pump system according to the present invention;

[0020] Figure 2 It is a schematic structural diagram of the second embodiment of a dual-effect ejector-type heat pump system according to the present invention;

[0021] Figure 3 It is a schematic structural diagram of the third embodiment of a dual-effect ejector-type heat pump system according to the present invention;

[0022] Figure 4 It is a schematic structural diagram of the fourth embodiment of a dual-effect ejector-type heat pump system according to the present invention. Specific Embodiments

[0023] First of all, it should be noted that the orientation words such as up, down, left, right, front, and back described in the present invention are only for description according to the drawings for easy understanding, and do not limit the technical solutions and the scope of claims of the present invention.

[0024] As Figure 1The first embodiment of a dual-effect ejector heat pump system according to the present invention is shown, including a generator 1, a first ejector 2, a second ejector 3, a condenser 4, a liquid storage tank 5, and an evaporator 6. The two ports at the primary side of the generator 1 are respectively connected to a heat source through heat exchange pipelines to form a first heat exchange loop. The outlet of the secondary side of the generator 1 is connected to the main stream inlet of the first ejector 2 through a first working medium pipeline 11. The outlet of the first ejector 2 is connected to the main stream inlet of the second ejector 3 through a second working medium pipeline 21. The outlet of the second ejector 3 is connected to the primary side inlet of the condenser 4 through a third working medium pipeline 31. The third working medium pipeline 31 is connected to the secondary flow inlet of the first ejector 2 through a fourth working medium pipeline 32. The primary side outlet of the condenser 4 is connected to the liquid storage tank 5 through a fifth working medium pipeline 41. The two ports at the secondary side of the condenser 4 are respectively connected to a heat supply end through heat exchange pipelines to form a heat supply loop. The liquid storage tank 5 is connected to the secondary side inlet of the generator 1 through a sixth working medium pipeline 51. The fifth working medium pipeline 41 is connected to the secondary side inlet of the evaporator 6 through a seventh working medium pipeline 42. The secondary side outlet of the evaporator 6 is connected to the secondary flow inlet of the second ejector 3 through an eighth working medium pipeline 61. The two ports at the primary side of the evaporator 6 are respectively connected to a heat source through heat exchange pipelines to form a second heat exchange loop. Among them, a working medium pump 7 is provided on the sixth working medium pipeline 51, and a throttle valve 8 is provided on the seventh working medium pipeline 42.

[0025] Through the above settings, a double-effect jet heat pump system with a simple structure, convenient operation, good stability and high safety is formed. In practical applications, after the system is started, the fluids in the first heat exchange circuit, the second heat exchange circuit, the heating circuit and the heat pump circuit circulate respectively. Among them, the fluids in the first heat exchange circuit and the second heat exchange circuit are high-temperature industrial wastewater or waste gas, referred to as high-temperature fluids for short, the fluid in the heating circuit is water or antifreeze, referred to as heating fluid for short, and the fluid in the heat pump circuit is refrigerant; the high-temperature fluids transfer heat to the refrigerant in the generator 1 and the evaporator 6 respectively, the refrigerant transfers heat to the heating fluid in the condenser 4, and the heating fluid transfers heat to the heating end; the high-pressure refrigerant saturated fluid entering the generator 1 absorbs heat and is transformed into high-pressure refrigerant vapor, the high-pressure refrigerant vapor is introduced into the first ejector 2 and mixed with the medium-pressure refrigerant vapor from the outlet of the second ejector 3, the refrigerant vapor from the outlet of the first ejector 2 is introduced into the second ejector 3 and mixed with the low-pressure refrigerant vapor from the evaporator 6, a part of the medium-pressure refrigerant vapor from the outlet of the second ejector 3 enters the condenser 4, and a part is introduced into the first ejector 2. The medium-pressure refrigerant vapor entering the condenser 4 releases heat and is transformed into medium-pressure refrigerant saturated liquid. A part of the medium-pressure refrigerant saturated liquid enters the liquid storage tank 5 and is pumped to increase the pressure by the working fluid pump 7 and then enters the generator 1, and a part is throttled and depressurized by the throttle valve 8 to become a refrigerant gas-liquid two-phase fluid and enters the evaporator 6. The refrigerant gas-liquid two-phase fluid entering the evaporator 6 absorbs heat and is transformed into low-pressure refrigerant vapor and is introduced into the second ejector 3. By setting two series-connected ejectors (the first ejector 2 and the second ejector 3), compared with the existing jet heat pump system, the expansion ratio of a single ejector is reduced, the internal loss of the ejector is reduced, the cascade utilization of energy is realized, the ejector efficiency is improved, and the outlet fluid of the second ejector (the second ejector 3) is entrained by the first ejector (the first ejector 2), realizing the recycling of heat and improving the overall COP of the system. It should be noted that the heat pump circuit includes a primary heat pump circuit and a secondary heat pump circuit. The primary heat pump circuit is formed by connecting the generator 1, the first ejector 2, the second ejector 3, the condenser 4 and the liquid storage tank 5 in series in sequence, and the secondary heat pump circuit is formed by connecting the second ejector 3, the condenser 4 and the evaporator 6 in series in sequence.

[0026] Such as Figure 2The second embodiment of a dual-effect ejector heat pump system according to the present invention is different from the first embodiment in that a heat exchanger 9 is added in the second embodiment. Specifically, the two ports at both ends of the primary side of the heat exchanger 9 are connected in series in the second refrigerant pipeline 21, and the two ports at both ends of the secondary side of the heat exchanger 9 are connected in series in the sixth refrigerant pipeline 51. This embodiment uses the heat exchanger 9 to preheat the refrigerant exiting from the outlet of the first ejector 2 for the refrigerant entering the generator 1, reducing the heat transfer temperature difference of the generator 1 and the irreversible loss. In practical applications, to ensure the stable operation of the system, the present invention usually arranges the refrigerant pump 7 on the sixth refrigerant pipeline 51 between the heat exchanger 9 and the liquid storage tank 5.

[0027] As Figure 3 The third embodiment of a dual-effect ejector heat pump system according to the present invention is different from the first embodiment in that a heat exchanger 9 is also added in the third embodiment. Specifically, the two ports at both ends of the primary side of the heat exchanger 9 are connected in series in the third refrigerant pipeline 31, and the two ports at both ends of the secondary side of the heat exchanger 9 are connected in series in the sixth refrigerant pipeline 51. This embodiment uses the heat exchanger 9 to preheat the refrigerant exiting from the outlet of the second ejector 3 for the refrigerant entering the generator 1, similarly reducing the heat transfer temperature difference of the generator 1 and the irreversible loss. In practical applications, to ensure the stable operation of the system, the present invention usually arranges the refrigerant pump 7 on the sixth refrigerant pipeline 51 between the heat exchanger 9 and the liquid storage tank 5; and sets the connection point of the fourth refrigerant pipeline 32 and the third refrigerant pipeline 31 at a position between the heat exchanger 9 and the condenser 4.

[0028] As Figure 4 The fourth embodiment of a dual-effect ejector heat pump system according to the present invention is different from the first embodiment in that a heat exchanger 9 is also added in the fourth embodiment. Specifically, the two ports at both ends of the primary side of the heat exchanger 9 are connected in series in the eighth refrigerant pipeline 61, and the two ports at both ends of the secondary side of the heat exchanger 9 are connected in series in the seventh refrigerant pipeline 42; the throttle valve 8 is arranged on the seventh refrigerant pipeline 42 between the heat exchanger 9 and the evaporator 6. This embodiment uses the heat exchanger 9 to conduct heat exchange between the refrigerant exiting from the outlet of the evaporator 6 and the refrigerant entering the throttle valve 8, reducing the temperature of the refrigerant at the inlet of the throttle valve 8, preventing steam from entering the throttle valve and affecting normal operation, and improving the stability and reliability.

[0029] In practical applications, for the convenience of detection and control, the present invention correspondingly sets temperature sensors T 1 and temperature sensors T 2 at the two ports at both ends of the primary side of the generator 1, correspondingly sets temperature sensors T 3 and temperature sensors T 4 at the two ports at both ends of the primary side of the evaporator 6, and correspondingly sets temperature sensors T 5 and temperature sensors T 6, a temperature sensor T is provided at the mainstream inlet of the first injector 2 7 and a pressure sensor P 1 , a temperature sensor T is provided at the outlet of the second injector 3 8 and a pressure sensor P 2 , and a controller connected to the above sensors is provided.

[0030] Based on the same concept, the present invention also provides a control method for the above dual-effect ejector heat pump system, which specifically includes the following steps:

[0031] S1. Start the system, and the fluids in the first heat exchange circuit, the second heat exchange circuit, the heating circuit, the first-stage heat pump circuit, and the second-stage heat pump circuit circulate respectively. Among them, the fluids in the first heat exchange circuit and the second heat exchange circuit are high-temperature industrial wastewater or waste gas, simply referred to as high-temperature fluids, the fluid in the heating circuit is water or antifreeze, simply referred to as heating fluid, and the fluids in the first-stage heat pump circuit and the second-stage heat pump circuit are refrigerants. The first-stage heat pump circuit is formed by sequentially connecting the generator 1, the first injector 2, the second injector 3, the condenser 4, and the liquid storage tank 5 end to end. The second-stage heat pump circuit is formed by sequentially connecting the second injector 3, the condenser 4, and the evaporator 6 end to end.

[0032] S2. The high-temperature fluid transfers heat to the refrigerant in the generator 1 and the evaporator 6 respectively, the refrigerant transfers heat to the heating fluid in the condenser 4, and the heating fluid transfers heat to the heating end.

[0033] S3. The high-pressure refrigerant saturated fluid entering the generator 1 absorbs heat and is transformed into high-pressure refrigerant vapor. The high-pressure refrigerant vapor is introduced into the first injector 2 and mixed with the medium-pressure refrigerant vapor from the outlet of the second injector 3. The refrigerant vapor at the outlet of the first injector 2 is introduced into the second injector 3 and mixed with the low-pressure refrigerant vapor from the evaporator 6. A part of the medium-pressure refrigerant vapor at the outlet of the second injector 3 enters the condenser 4, and a part is introduced into the first injector 2. The medium-pressure refrigerant vapor entering the condenser 4 releases heat and is transformed into medium-pressure refrigerant saturated liquid. A part of the medium-pressure refrigerant saturated liquid enters the liquid storage tank 5 and is pumped and boosted by the working fluid pump 7 and then enters the generator 1. A part is throttled and depressurized by the throttle valve 8 to become a refrigerant gas-liquid two-phase fluid and enters the evaporator 6. The refrigerant gas-liquid two-phase fluid entering the evaporator 6 absorbs heat and is transformed into low-pressure refrigerant vapor and is introduced into the second injector 3.

[0034] The control method of the dual-effect ejector heat pump system provided by the present invention has the advantages of simple process, safety and reliability.

[0035] The above embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of protection claimed by the present invention. Without departing from the design concept of the present invention, various deformations made by those skilled in the art based on the technical solution of the present invention should fall within the protection scope determined by the claims of the present invention.

Claims

1. A double-effect jet heat pump system, characterized in that: The invention comprises a generator (1), a first ejector (2), a second ejector (3), a condenser (4), a liquid storage tank (5) and an evaporator (6); two ports on the primary side of the generator (1) are respectively connected to a heat source through heat exchange pipelines to form a first heat exchange circuit; the secondary side outlet of the generator (1) is connected to the mainstream inlet of the first ejector (2) through a first working fluid pipeline (11); the outlet of the first ejector (2) is connected to the mainstream inlet of the second ejector (3) through a second working fluid pipeline (21); the outlet of the second ejector (3) is connected to the primary side inlet of the condenser (4) through a third working fluid pipeline (31); the third working fluid pipeline (31) is connected to the secondary flow inlet of the first ejector (2) through a fourth working fluid pipeline (32); the primary side outlet of the condenser (4) is connected to the secondary flow inlet of the first ejector (2) through a fourth working fluid pipeline (32); The side outlet is connected to the liquid storage tank (5) through a fifth working fluid pipeline (41); the two secondary side ports of the condenser (4) are respectively connected to the heat supply end through heat exchange pipelines to form a heat supply circuit; the liquid storage tank (5) is connected to the secondary side inlet of the generator (1) through a sixth working fluid pipeline (51); the fifth working fluid pipeline (41) is connected to the secondary side inlet of the evaporator (6) through a seventh working fluid pipeline (42); the secondary side outlet of the evaporator (6) is connected to the secondary flow inlet of the second ejector (3) through an eighth working fluid pipeline (61); the two primary side ports of the evaporator (6) are respectively connected to the heat source through heat exchange pipelines to form a second heat exchange circuit; the sixth working fluid pipeline (51) is provided with a working fluid pump (7); and the seventh working fluid pipeline (42) is provided with a throttle valve (8).

2. The double-effect jet heat pump system according to claim 1, characterized in that: It also includes a heat exchanger (9), wherein two ports on the primary side of the heat exchanger (9) are connected in series to the second working fluid pipeline (21), and two ports on the secondary side of the heat exchanger (9) are connected in series to the sixth working fluid pipeline (51).

3. The double-effect jet heat pump system according to claim 2, characterized in that: The working fluid pump (7) is arranged on a sixth working fluid pipeline (51) between the heat exchanger (9) and the liquid storage tank (5).

4. The double-effect jet heat pump system according to claim 1, characterized in that: It also includes a heat exchanger (9), wherein two ports on the primary side of the heat exchanger (9) are connected in series to the third working fluid pipeline (31), and two ports on the secondary side of the heat exchanger (9) are connected in series to the sixth working fluid pipeline (51).

5. The double-effect jet heat pump system according to claim 4, characterized in that: The working fluid pump (7) is arranged on a sixth working fluid pipeline (51) between the heat exchanger (9) and the liquid storage tank (5).

6. The double-effect jet heat pump system according to claim 4, characterized in that: The connection point between the fourth working fluid pipeline (32) and the third working fluid pipeline (31) is located between the heat exchanger (9) and the condenser (4).

7. The double-effect jet heat pump system according to claim 1, characterized in that: It also includes a heat exchanger (9), wherein two ports on the primary side of the heat exchanger (9) are connected in series to the eighth working fluid pipeline (61), and two ports on the secondary side of the heat exchanger (9) are connected in series to the seventh working fluid pipeline (42).

8. The double-effect jet heat pump system according to claim 7, characterized in that: The throttle valve (8) is arranged on the seventh working fluid pipeline (42) between the heat exchanger (9) and the evaporator (6).

9. The double-effect jet heat pump system according to claim 1, characterized in that: The two ports on the primary side of the generator (1) are respectively provided with a temperature sensor T1 and a temperature sensor T2, the two ports on the primary side of the evaporator (6) are respectively provided with a temperature sensor T3 and a temperature sensor T4, the two ports on the secondary side of the condenser (4) are respectively provided with a temperature sensor T5 and a temperature sensor T6, the mainstream inlet of the first ejector (2) is provided with a temperature sensor T7 and a pressure sensor P1, and the outlet of the second ejector (3) is provided with a temperature sensor T8 and a pressure sensor P2.

10. A control method for the double-effect jet heat pump system according to claim 1, characterized in that: The following steps are involved: S1. Start the system, and the fluids in the first heat exchange circuit, the second heat exchange circuit, the heating circuit, the primary heat pump circuit, and the secondary heat pump circuit circulate respectively, wherein the fluids in the first heat exchange circuit and the second heat exchange circuit are high-temperature industrial waste water or waste gas, referred to as high-temperature fluid, the fluid in the heating circuit is water or antifreeze, referred to as heating fluid, the fluids in the primary heat pump circuit and the secondary heat pump circuit are refrigerants, the primary heat pump circuit is composed of a generator (1), a first ejector (2), a second ejector (3), a condenser (4), and a liquid storage tank (5) connected end to end in sequence, and the secondary heat pump circuit is composed of a second ejector (3), a condenser (4), and an evaporator (6) connected end to end in sequence; S2, the high temperature fluid transfers heat to the refrigerant in the generator (1) and the evaporator (6), the refrigerant transfers heat to the heating fluid in the condenser (4), and the heating fluid transfers heat to the heating end; S3. The high-pressure refrigerant saturated fluid entering the generator (1) absorbs heat and is converted into high-pressure refrigerant vapor. The high-pressure refrigerant vapor is passed into the first ejector (2) and is mixed with the medium-pressure refrigerant vapor from the outlet of the second ejector (3). The refrigerant vapor at the outlet of the first ejector (2) is passed into the second ejector (3) and is mixed with the low-pressure refrigerant vapor from the evaporator (6). A portion of the medium-pressure refrigerant vapor at the outlet of the second ejector (3) enters the condenser (4) and a portion of it is passed into the first ejector (2). The medium-pressure refrigerant vapor entering the condenser (4) releases heat and is converted into medium-pressure refrigerant saturated liquid. A portion of the medium-pressure refrigerant saturated liquid enters the liquid storage tank (5) and is pumped and pressurized by the working fluid pump (7) and then enters the generator (1). A portion of it is throttled and depressurized by the throttle valve (8) and then converted into a refrigerant gas-liquid two-phase fluid and enters the evaporator (6). The refrigerant gas-liquid two-phase fluid entering the evaporator (6) absorbs heat and is converted into low-pressure refrigerant vapor and is passed into the second ejector (3).

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