Two-stage absorption-compression heat coupling heat pump system and working method

Abstract

The present invention provides a two-stage absorption-compression heat-coupled heat pump system and operating method, comprising a compression heat pump sub-circulation system comprising a compressor, a compression cycle condenser, and a compression cycle evaporator, the compressor, multiple compression cycle condensers, and compression cycle evaporators being sequentially connected by pipelines; and a two-stage absorption heat pump sub-circulation system comprising a high-pressure absorber, a low-pressure absorber, a generator, a solution heat recovery device, an absorption cycle condenser, and an absorption cycle low-pressure evaporator. By providing the compression heat pump sub-circulation system and the two-stage absorption heat pump sub-circulation system, the temperature rise capability of the compression heat pump and the efficiency of the two-stage absorption heat pump are improved. This system also provides an efficient circulation method for raising the temperature of low-grade heat sources and recovering waste heat, and helps improve the efficiency of waste heat recovery.

Description

Technical Field

[0001] The present invention relates to the technical field of energy recovery, and in particular to a two-stage absorption-compression thermally coupled heat pump system and a working method. Background Art

[0002] Energy and environmental issues are two major challenges to sustainable development in today's society. In the industrial sector, the extensive use of energy in production processes exacerbates the imbalance between energy supply and demand. The direct release of industrial waste heat into the environment results in a significant amount of low-grade thermal energy being wasted. To reduce waste heat, heat pump technology can be used to upgrade heat from industrial waste heat or the environment, outputting high-quality thermal energy for reuse. This not only efficiently utilizes energy, but also reduces waste heat, resulting in significant economic benefits.

[0003] Heat pump technology can utilize low-quality heat input to produce high-quality heat output. Typical heat pump technologies can be categorized as compression heat pumps and absorption heat pumps. Compression heat pumps are driven by electrical or mechanical energy to increase the heat temperature. Absorption heat pumps can be categorized as either Type I or Type II absorption heat pumps. Type I absorption heat pumps utilize high-temperature input to generate medium-temperature heat output, with the output heat output having a higher power than the input heat. Type II absorption heat pumps utilize medium-temperature heat input to generate high-temperature heat output, with the output heat output having a lower power than the input heat.

[0004] A Chinese patent application, publication number CN110030769B, discloses a medium- and low-temperature heat energy supply system based on a warming absorption-compression heat exchange system. The system comprises a medium- and low-temperature heat source, a heat source station, a primary network, a thermal power station, and a secondary network, all connected in sequence. The heat source station is a first water-to-water heat exchanger, and the thermal power station is a compression heat exchanger unit or a second water-to-water heat exchanger. The medium- and low-temperature heat source can be medium- and low-temperature industrial waste heat, medium- and deep-seated geothermal heat, or medium- and low-temperature circulating water from a solar collector. This system utilizes heat exchangers configured at the medium- and low-temperature heat source station based on the characteristics of the medium- and low-temperature heat carriers, and compression heat exchangers configured at the thermal power station based on the characteristics of the heat users. This system can significantly reduce the return water temperature of the primary heating network and increase the primary supply water temperature.

[0005] Both compression heat pumps and absorption heat pumps have a variety of different cycles, such as the cascade compression cycle, double-effect absorption cycle, and two-stage absorption cycle. However, both compression heat pumps and absorption heat pumps have their own problems: although compression heat pumps have high efficiency, their temperature-raising capacity is limited, and they require high-quality electricity, making them suitable for medium and low-temperature ranges. Absorption heat pumps consume low-quality thermal energy and can achieve higher output temperatures, but they require higher input temperatures and have lower energy efficiency, making them more suitable for high-temperature ranges. The two heat pump technologies have different characteristics in terms of efficiency, adaptability, and energy consumption types. Effectively combining the two heat pump technologies and achieving complementary advantages is an effective way to address the shortcomings of the two heat pump technologies. Summary of the Invention

[0006] In view of the defects in the prior art, the object of the present invention is to provide a two-stage absorption-compression thermally coupled heat pump system and a working method.

[0007] According to the present invention, a two-stage absorption-compression heat coupling heat pump system is provided, which includes a compression heat pump sub-circulation system: including a compressor, a compression cycle condenser and a compression cycle evaporator, and the compressor, multiple compression cycle condensers and compression cycle evaporators are connected in sequence through pipelines; a two-stage absorption heat pump sub-circulation system: including a high-pressure stage absorber, a low-pressure stage absorber, a generator, a solution heat recovery device, an absorption cycle condenser and an absorption cycle low-pressure stage evaporator; one of the compression cycle condensers is arranged in the generator, and the first outlet of the generator is connected to the first inlet of the high-pressure stage absorber through multiple solution heat recovery devices, and the outlet of the high-pressure stage absorber is connected to the first inlet of the low-pressure stage absorber through the solution heat recovery device. The absorption cycle high-pressure evaporator is arranged in the low-pressure stage absorber, and the outlet of the absorption cycle high-pressure stage evaporator is connected to the second inlet of the high-pressure stage absorber, and the second outlet of the low-pressure stage absorber is connected to the inlet of the generator through the solution heat recovery device; the second outlet of the generator is connected to the inlet of the absorption cycle condenser, and the compression cycle evaporator is arranged in the absorption cycle condenser, and the first outlet of the absorption cycle condenser is connected to the inlet of the absorption cycle high-pressure stage evaporator, and the second outlet of the absorption cycle condenser is connected to the inlet of the absorption cycle low-pressure stage evaporator. The other compression cycle condenser is arranged in the absorption cycle low-pressure stage evaporator, and the outlet of the absorption cycle low-pressure stage evaporator is connected to the third inlet of the low-pressure stage absorber.

[0008] Preferably, the compression cycle condenser includes a first compression cycle condenser and a second compression cycle condenser; the first compression cycle condenser is arranged in the generator, and the second compression cycle condenser is arranged in the absorption cycle low-pressure stage evaporator.

[0009] Preferably, the first outlet of the generator is connected to a solution pump, and the outlet of the solution pump is connected to the first inlet of the high-pressure absorber through a plurality of solution heat recovery devices.

[0010] Preferably, the outlet of the high-pressure stage absorber is communicated with the third throttle valve through the solution heat recovery device, and the outlet of the third throttle valve is communicated with the first inlet of the low-pressure stage absorber.

[0011] Preferably, the absorption cycle condenser is connected to the inlet of the absorption cycle high-pressure stage evaporator through a second refrigerant pump.

[0012] Preferably, the second outlet of the absorption cycle condenser is communicated with the inlet of the absorption cycle low-pressure stage evaporator through the first refrigerant pump.

[0013] Preferably, the second outlet of the low-pressure stage absorber is communicated with one end of a second throttle valve through a solution heat recovery device, and the other end of the second throttle valve is communicated with the inlet of the generator.

[0014] Preferably, the outlet of the second compression cycle condenser is communicated with one end of the first throttle valve, and the other end of the first throttle valve is communicated with the inlet of the compression cycle evaporator.

[0015] According to the present invention, a working method of a two-stage absorption-compression thermally coupled heat pump system is provided, the working method comprising:

[0016] The working method of the compression heat pump sub-circulation system is as follows: the first refrigerant vapor enters the first compression cycle condenser from the compressor to condense and heat the generator to form the first refrigerant liquid;

[0017] The first refrigerant liquid enters the second compression cycle condenser from the first compression cycle condenser and condenses, heating the absorption cycle low-pressure stage evaporator and forming the second refrigerant liquid;

[0018] The second refrigerant liquid enters the compression cycle evaporator from the second compression cycle condenser through the first throttle valve and absorbs heat from the low-grade heat source and / or waste heat and / or heat from the absorption cycle condenser to form a second refrigerant vapor;

[0019] The second refrigerant vapor is compressed by the compressor from the compression cycle evaporator to produce the first refrigerant vapor, and enters the first compression cycle condenser;

[0020] The working method of the two-stage absorption heat pump sub-circulation system is as follows: the solution of the generator enters the high-pressure absorber through the solution pump and multiple solution heat recovery devices;

[0021] The solution releases heat output after absorbing the fifth refrigerant vapor from the high-pressure stage evaporator of the absorption cycle in the high-pressure stage absorber;

[0022] The solution flows from the high-pressure absorber through the second solution heat recovery device and the third throttle valve into the low-pressure absorber, absorbs the fourth refrigerant vapor from the low-pressure evaporator of the absorption cycle, and heats the high-pressure evaporator of the absorption cycle;

[0023] The solution is returned from the low-pressure absorber to the generator through the first solution heat recovery device and the second throttle valve. The solution returned to the generator is the recovered solution.

[0024] The recovered solution is heated in the generator through the first compression cycle condenser to produce the third refrigerant vapor, and the remaining solution then enters the solution pump;

[0025] After the third refrigerant vapor enters the absorption cycle condenser from the generator and is condensed, the compression cycle evaporator is heated to form a third refrigerant liquid. A portion of the third refrigerant liquid enters the absorption cycle low-pressure stage evaporator from the absorption cycle condenser through the first refrigerant pump. After a portion of the third refrigerant liquid enters the absorption cycle low-pressure stage evaporator, it absorbs heat from the second compression cycle condenser to form a fourth refrigerant vapor and enters the low-pressure stage absorber.

[0026] Another part of the third refrigerant liquid enters the absorption cycle high-pressure evaporator from the absorption cycle condenser through the second refrigerant pump. After entering the absorption cycle high-pressure evaporator, the other part of the third refrigerant liquid absorbs heat from the low-pressure absorber to form the fifth refrigerant vapor and enters the high-pressure absorber.

[0027] Preferably, when waste heat is generated, the waste heat is transferred to the compression cycle evaporator.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The present invention achieves an improvement in the temperature rise capacity of the compression heat pump and the efficiency of the two-stage absorption heat pump by providing a compression heat pump sub-circulation system and a two-stage absorption heat pump sub-circulation system, and provides an efficient circulation method for raising the temperature of low-grade heat sources and recovering waste heat, and helps to improve the efficiency of waste heat recovery.

[0030] 2. The present invention exchanges heat through the first compression cycle condenser and the generator, the second compression cycle condenser and the absorption cycle low-pressure stage evaporator, the absorption cycle condenser and the compression cycle evaporator, the low-pressure stage absorber and the absorption cycle high-pressure stage evaporator, the solution entering the high-pressure stage absorber from the solution pump and the solution entering the second throttle valve from the low-pressure stage absorber are heat exchanged in the first solution heat recovery device, and the solution entering the high-pressure stage absorber from the solution pump and the solution entering the third throttle valve from the high-pressure stage absorber are heat exchanged in the second solution heat recovery device, thereby realizing heat exchange connection between the compression heat pump sub-circulation system and the two-stage absorption heat pump sub-circulation system, which helps to improve energy absorption efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0032] Figure 1 This is a schematic diagram of the overall structure of a heat pump system that mainly embodies the two-stage absorption-compression thermal coupling of the present invention.

[0033] As shown in the figure:

[0034] High pressure absorber 1 Second throttle valve 10

[0035] Generator 2 Third throttle valve 11

[0036] Absorption cycle condenser 3 First refrigerant pump 12

[0037] Absorption cycle low pressure stage evaporator 4 Second refrigerant pump 13

[0038] Low pressure absorber 5 compressor 21

[0039] Absorption cycle high pressure stage evaporator 6 First compression cycle condenser 22

[0040] First solution heat recovery device 7 Second compression cycle condenser 23

[0041] Second solution heat recovery device 8 First throttle valve 24

[0042] Solution pump 9 Compression cycle evaporator 25 DETAILED DESCRIPTION

[0043] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0044] Example 1

[0045] like Figure 1 As shown, a two-stage absorption-compression heat coupled heat pump system provided according to the present invention includes a compression heat pump sub-circulation system and a two-stage absorption heat pump sub-circulation system. The compression heat pump sub-circulation system includes a compressor 21, a compression cycle condenser, a first throttle valve 24 and a compression cycle evaporator 25. The compression cycle condenser includes a first compression cycle condenser 22 and a second compression cycle condenser 23.

[0046] The compressor 21, multiple compression cycle condensers, and the compression cycle evaporator 25 are sequentially connected through pipelines. Specifically, the outlet of the compressor 21 is connected to the inlet of the first compression cycle condenser 22, the outlet of the first compression cycle condenser 22 is connected to the inlet of the second compression cycle condenser 23, the outlet of the second compression cycle condenser 23 is connected to one end of the first throttle valve 24, the other end of the first throttle valve 24 is connected to the inlet of the compression cycle evaporator 25, and the outlet of the compression cycle evaporator 25 is connected to the inlet of the compressor 21.

[0047] The two-stage absorption heat pump sub-circulation system includes a high-pressure stage absorber 1, a low-pressure stage absorber 5, a generator 2, a solution heat recovery device, an absorption cycle condenser 3, an absorption cycle low-pressure stage evaporator 4, an absorption cycle high-pressure stage evaporator 6, a solution pump 9, a second throttle valve 10, a third throttle valve 11, a first refrigerant pump 12 and a second refrigerant pump 13, and the solution heat recovery device includes a first solution heat recovery device 7 and a second solution heat recovery device 8.

[0048] Specifically, a compression cycle condenser is arranged in the generator 2, the first outlet of the generator 2 is connected to the first inlet of the high-pressure stage absorber 1 through multiple solution heat recovery devices, the outlet of the high-pressure stage absorber 1 is connected to the first inlet of the low-pressure stage absorber 5 through the solution heat recovery device, the absorption cycle high-pressure stage evaporator 6 is arranged in the low-pressure stage absorber 5, the outlet of the absorption cycle high-pressure stage evaporator 6 is connected to the second inlet of the high-pressure stage absorber 1, and the second outlet of the low-pressure stage absorber 5 is connected to the inlet of the generator 2 through the solution heat recovery device.

[0049] The second outlet of the generator 2 is connected to the inlet of the absorption cycle condenser 3, the compression cycle evaporator 25 is arranged in the absorption cycle condenser 3, the first outlet of the absorption cycle condenser 3 is connected to the inlet of the absorption cycle high-pressure stage evaporator 6, the second outlet of the absorption cycle condenser 3 is connected to the inlet of the absorption cycle low-pressure stage evaporator 4, another compression cycle condenser is arranged in the absorption cycle low-pressure stage evaporator 4, and the outlet of the absorption cycle low-pressure stage evaporator 4 is connected to the third inlet of the low-pressure stage absorber 5.

[0050] More specifically, the compression cycle condenser includes a first compression cycle condenser 22 and a second compression cycle condenser 23 ; the first compression cycle condenser is arranged in the generator 2 , and the second compression cycle condenser 23 is arranged in the absorption cycle low-pressure stage evaporator 4 .

[0051] The first outlet of the generator 2 is connected to a solution pump 9 , and the outlet of the solution pump 9 is connected to the first inlet of the high-pressure absorber 1 through a plurality of solution heat recovery devices.

[0052] The outlet of the high-pressure stage absorber 1 is communicated with the third throttle valve 11 through the solution heat recovery device, and the outlet of the third throttle valve 11 is communicated with the first inlet of the low-pressure stage absorber 5 .

[0053] The absorption cycle condenser 3 is communicated with the inlet of the absorption cycle high-pressure stage evaporator 6 through the second refrigerant pump 13 .

[0054] The second outlet of the absorption cycle condenser 3 is communicated with the inlet of the absorption cycle low-pressure stage evaporator 4 through the first refrigerant pump 12 .

[0055] The second outlet of the low-pressure stage absorber 5 is connected to one end of the second throttle valve 10 through the solution heat recovery device, and the other end of the second throttle valve 10 is connected to the inlet of the generator 2.

[0056] The outlet of the second compression cycle condenser 23 is communicated with one end of the first throttle valve 24 , and the other end of the first throttle valve 24 is communicated with the inlet of the compression cycle evaporator 25 .

[0057] According to the present invention, a working method of a two-stage absorption-compression thermally coupled heat pump system is provided, and the working method includes a working method of a compression heat pump sub-circulation system and a working method of a two-stage absorption heat pump sub-circulation system.

[0058] The compression heat pump sub-circulation system works as follows: The first refrigerant vapor enters the first compression cycle condenser 22 from the compressor 21, condenses, and heats the generator 2, forming a first refrigerant liquid. The first refrigerant liquid enters the second compression cycle condenser 23 from the first compression cycle condenser 22, condenses, and heats the absorption cycle low-pressure stage evaporator 4, forming a second refrigerant liquid. The second refrigerant liquid enters the compression cycle evaporator 25 from the second compression cycle condenser 23 through the first throttle valve 24, and absorbs heat from the low-grade heat source and / or waste heat and / or heat from the absorption cycle condenser 3 to form a second refrigerant vapor. The second refrigerant vapor is compressed by the compressor 21 from the compression cycle evaporator 25 to produce the first refrigerant vapor, which then enters the first compression cycle condenser 22.

[0059] The two-stage absorption heat pump sub-circulation system works as follows: The solution from generator 2 enters the high-pressure absorber 1 through a solution pump 9 and multiple solution heat recovery devices. After the solution absorbs the fifth refrigerant vapor from the absorption cycle high-pressure evaporator 6 in the high-pressure absorber 1, it releases heat for output. The solution enters the low-pressure absorber 5 from the high-pressure absorber 1 through the second solution heat recovery device 8 and the third throttle valve 11. After absorbing the fourth refrigerant vapor from the absorption cycle low-pressure evaporator 4, the absorption cycle high-pressure evaporator 6 is heated. The solution returns to the generator 2 from the low-pressure absorber 5 through the first solution heat recovery device 7 and the second throttle valve 10. The solution returned to the generator 2 is the recovered solution. After the recovered solution is heated in the first compression cycle condenser 22 in the generator 2, the third refrigerant vapor is generated. The remaining solution then enters the solution pump 9. After the third refrigerant vapor enters the absorption cycle condenser 3 from the generator 2 and is condensed, it heats the compression cycle evaporator 25 and forms a third refrigerant liquid. A portion of the third refrigerant liquid flows from the absorption cycle condenser 3 through the first refrigerant pump 12 into the absorption cycle low-pressure stage evaporator 4. After a portion of the third refrigerant liquid enters the absorption cycle low-pressure stage evaporator 4, it absorbs heat from the second compression cycle condenser 23 to form a fourth refrigerant vapor and enters the low-pressure stage absorber 5. Another portion of the third refrigerant liquid flows from the absorption cycle condenser 3 through the second refrigerant pump 13 into the absorption cycle high-pressure stage evaporator 6. Another portion of the third refrigerant liquid enters the absorption cycle high-pressure stage evaporator 6, absorbs heat from the low-pressure stage absorber 5, forms a fifth refrigerant vapor, and enters the high-pressure stage absorber 1.

[0060] It should be noted that when waste heat is generated, the waste heat is transferred to the compression cycle evaporator 25 .

[0061] Specifically, when the circulation system operates in working mode, waste heat is input into the evaporator of the compression heat pump sub-circulation system. After being heated by the compression heat pump sub-circulation system, it is output from the condenser of the compression heat pump sub-circulation system to the low-pressure evaporator 4 and generator 2 of the two-stage absorption heat pump sub-circulation system. The heat is further heated by the two-stage absorption heat pump sub-circulation system before being output from the high-pressure absorber 1 of the two-stage absorption heat pump sub-circulation system. Furthermore, the heat released by the absorption cycle condenser 3 can be input into the compression cycle evaporator 25, thereby reducing the input of waste heat and improving overall thermal efficiency. The working mode has a relatively high output temperature.

[0062] More specifically, the heat output of the compression heat pump sub-circulation system can simultaneously enter the absorption cycle low-pressure stage evaporator 4 and the generator 2 of the two-stage absorption heat pump sub-circulation system, can sequentially enter the absorption cycle low-pressure stage evaporator 4 and the generator 2 of the two-stage absorption heat pump sub-circulation system, or can sequentially enter the generator 2 and the absorption cycle low-pressure stage evaporator 4 of the two-stage absorption heat pump sub-circulation system.

[0063] One feasible implementation method is to use lithium bromide aqueous solution as the working fluid pair of the two-stage absorption heat pump sub-circulation system, and the heat output of the compression heat pump sub-circulation system sequentially heats the absorption cycle low-pressure stage evaporator 4 and generator 2 of the two-stage absorption heat pump sub-circulation system to reduce the crystallization risk of the system. When using ammonia aqueous solution as the working fluid pair of the two-stage absorption heat pump sub-circulation, the condensation heat of the compression heat pump sub-circulation system sequentially heats the generator 2 and the absorption cycle low-pressure stage evaporator 4 of the two-stage absorption heat pump sub-circulation system to reduce the system pressure, enhance system safety, and reduce the power consumption of the solution pump 9, the first refrigerant pump 12, and the second refrigerant pump 13.

[0064] The compression cycle condenser outputs heat to the generator 2 and the absorption cycle low-pressure evaporator 4 in various heat exchange modes: the first heat exchange mode is for the heat output of the first compression cycle condenser 22 and the second compression cycle condenser 23 to be simultaneously input to the absorption cycle low-pressure evaporator 4 and the generator 2; the second heat exchange mode is for the heat output of the compression cycle condenser to be sequentially input to the absorption cycle low-pressure evaporator 4 and the generator 2; and the third heat exchange mode is for the heat output of the compression cycle condenser to be sequentially input to the generator 2 and the absorption cycle low-pressure evaporator 4. The first heat exchange mode is suitable for situations where the output power of the compression heat pump sub-cycle is high. The second heat exchange mode is suitable for situations where lithium bromide aqueous solution is used as the working fluid in a two-stage absorption heat pump sub-cycle, and has the characteristic of low crystallization risk. The third heat exchange mode is suitable for situations where ammonia aqueous solution is used as the working fluid pair in a two-stage absorption heat pump sub-cycle, and has the characteristic of reducing system pressure, the power consumption of the solution pump 9, the power consumption of the first refrigerant pump 12, and the power consumption of the second refrigerant pump 13.

[0065] Example 2

[0066] Based on Example 1, a two-stage absorption-compression heat-coupled heat pump system provided by the present invention has the following main internal heat exchange in the circulation system operating in working mode: the first compression cycle condenser 22 exchanges heat with the generator 2, the second compression cycle condenser 23 exchanges heat with the absorption cycle low-pressure stage evaporator 4, the absorption cycle condenser 3 exchanges heat with the compression cycle evaporator 25, the low-pressure stage absorber 5 exchanges heat with the absorption cycle high-pressure stage evaporator 6, the solution entering the high-pressure stage absorber 1 from the solution pump 9 and the solution entering the second throttle valve 10 from the low-pressure stage absorber 5 exchange heat in the first solution heat recovery device 7, and the solution entering the high-pressure stage absorber 1 from the solution pump 9 and the solution entering the third throttle valve 11 from the high-pressure stage absorber 1 exchange heat in the second solution heat recovery device 8. The external heat exchange of the circulation system is as follows: the waste heat is input to the compression cycle evaporator 25, and the high-pressure stage absorber 1 outputs heat to the outside.

[0067] When operating in working mode, the working medium flow inside the compression heat pump sub-circulation system is as follows: the refrigerant vapor enters the first compression cycle condenser 22 from the compressor 21, condenses and releases heat to the generator 2, and then enters the second compression cycle condenser 23 to continue condensing into refrigerant liquid and releases heat to the absorption cycle low-pressure stage evaporator 4. The refrigerant liquid enters the first throttle valve 24 to reduce the pressure and then enters the compression cycle evaporator 25 to absorb the waste heat and heat from the absorption cycle condenser 3 and then evaporates into refrigerant vapor. The refrigerant vapor enters the compressor 21, is compressed and pressurized, and then enters the first compression cycle condenser 22 again.

[0068] When operating in working mode, the working medium flow inside the two-stage absorption heat pump sub-circulation system is as follows: the solution in the generator 2 passes through the solution pump 9, the first solution heat recovery device 7 and the second solution heat exchanger 8 and then enters the high-pressure stage absorber 1. The solution entering the high-pressure stage absorber 1 releases heat output after absorbing the refrigerant vapor from the absorption cycle high-pressure stage evaporator 6, and passes through the second solution heat exchanger 8 and the third throttle valve 11 to enter the low-pressure stage absorber 5. The solution entering the low-pressure stage absorber 5 continues to absorb the refrigerant vapor from the absorption cycle low-pressure stage evaporator 4 and releases heat to the absorption cycle high-pressure stage evaporator 6, and then passes through the first solution heat recovery device 7 and the second throttle valve 10 back to the generator 2. The solution returning to the generator 2 passes through the second solution heat recovery device 7 and the second throttle valve 10. Heating of the first compression cycle condenser 22 generates refrigerant vapor, which re-enters the solution pump 9. The refrigerant vapor generated in this process enters the absorption cycle condenser 3. The refrigerant vapor in the absorption cycle condenser 3 condenses into refrigerant liquid and releases heat to the compression cycle evaporator 25. A portion of the refrigerant liquid in the absorption cycle condenser 3 passes through the first refrigerant pump 12 and enters the absorption cycle low-pressure stage evaporator 4. Heated by the second compression cycle condenser 23, it evaporates into refrigerant vapor and enters the low-pressure stage absorber 5. Another portion of the refrigerant liquid in the absorption cycle condenser 3 passes through the second refrigerant pump 13 and enters the absorption cycle high-pressure stage evaporator 6. Heated by the low-pressure stage absorber 5, it evaporates into refrigerant vapor and enters the high-pressure stage absorber 1. The refrigerant used in the two-stage absorption heat pump sub-cycle may or may not be the refrigerant used in the compression heat pump sub-cycle.

[0069] When running in working mode, there are three connection modes between the compressor 21 and the first compression cycle condenser 22 and the second compression cycle condenser 23. Figure 1In the connection method shown, the outlet of the compressor 21 is first connected to the first compression cycle condenser 22 for heat exchange with the generator 2, and then connected to the second compression cycle condenser 23 for heat exchange with the absorption cycle low-pressure stage evaporator 4. In addition, the outlet of the compressor 21 can be first connected to the second compression cycle condenser 23 for heat exchange with the absorption cycle low-pressure stage evaporator 4, and then connected to the first compression cycle condenser 22 for heat exchange with the generator 2; or the outlet of the compressor 21 can be simultaneously connected to the first compression cycle condenser 22 for heat exchange with the generator 2 and the second compression cycle condenser 23 for heat exchange with the absorption cycle low-pressure stage evaporator 4.

[0070] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A two-stage absorption-compression heat pump system, characterized in that: include: The compression heat pump sub-circulation system comprises a compressor (21), a compression cycle condenser, and a compression cycle evaporator (25), wherein the compressor (21), the plurality of compression cycle condensers, and the compression cycle evaporator (25) are sequentially connected via pipelines; A two-stage absorption heat pump subcirculation system comprising a high-pressure absorber (1), a low-pressure absorber (5), a generator (2), a solution heat recovery device, an absorption cycle high-pressure evaporator (6), an absorption cycle condenser (3), and an absorption cycle low-pressure evaporator (4); The compression cycle condenser is arranged in the generator (2), the first outlet of the generator (2) is connected to the first inlet of the high-pressure absorber (1) through a plurality of solution heat recovery devices, the outlet of the high-pressure absorber (1) is connected to the first inlet of the low-pressure absorber (5) through the solution heat recovery device, the absorption cycle high-pressure evaporator (6) is arranged in the low-pressure absorber (5), the outlet of the absorption cycle high-pressure evaporator (6) is connected to the second inlet of the high-pressure absorber (1), and the second outlet of the low-pressure absorber (5) is connected to the inlet of the generator (2) through the solution heat recovery device; The second outlet of the generator (2) is connected to the inlet of the absorption cycle condenser (3), the compression cycle evaporator (25) is arranged in the absorption cycle condenser (3), the first outlet of the absorption cycle condenser (3) is connected to the inlet of the absorption cycle high-pressure stage evaporator (6), the second outlet of the absorption cycle condenser (3) is connected to the inlet of the absorption cycle low-pressure stage evaporator (4), and the other compression cycle condenser is arranged in the absorption cycle low-pressure stage evaporator (4), and the outlet of the absorption cycle low-pressure stage evaporator (4) is connected to the third inlet of the low-pressure stage absorber (5).

2. The two-stage absorption-compression heat pump system according to claim 1, characterized in that: The compression cycle condenser includes a first compression cycle condenser (22) and a second compression cycle condenser (23); The first compression cycle condenser is arranged in the generator (2), and the second compression cycle condenser (23) is arranged in the absorption cycle low-pressure stage evaporator (4).

3. The two-stage absorption-compression heat pump system according to claim 1, characterized in that: The first outlet of the generator (2) is connected to a solution pump (9), and the outlet of the solution pump (9) is connected to the first inlet of the high-pressure absorber (1) through a plurality of solution heat recovery devices.

4. The two-stage absorption-compression heat pump system according to claim 1, characterized in that: The outlet of the high-pressure absorber (1) is communicated with the third throttle valve (11) through the solution heat recovery device, and the outlet of the third throttle valve (11) is communicated with the first inlet of the low-pressure absorber (5).

5. The two-stage absorption-compression heat pump system according to claim 1, characterized in that: The absorption cycle condenser (3) is connected to the inlet of the absorption cycle high-pressure stage evaporator (6) through the second refrigerant pump (13).

6. The two-stage absorption-compression heat pump system according to claim 1, characterized in that: The second outlet of the absorption cycle condenser (3) is communicated with the inlet of the absorption cycle low-pressure stage evaporator (4) through the first refrigerant pump (12).

7. The two-stage absorption-compression heat pump system according to claim 1, characterized in that: The second outlet of the low-pressure stage absorber (5) is connected to one end of the second throttle valve (10) through the solution heat recovery device, and the other end of the second throttle valve (10) is connected to the inlet of the generator (2).

8. The two-stage absorption-compression heat pump system according to claim 2, characterized in that: The outlet of the second compression cycle condenser (23) is communicated with one end of the first throttle valve (24), and the other end of the first throttle valve (24) is communicated with the inlet of the compression cycle evaporator (25).

9. A method for operating a two-stage absorption-compression heat pump system, characterized in that: The heat pump system of the two-stage absorption-compression thermal coupling according to any one of claims 1 to 8 has an operating method comprising: The working method of the compression heat pump sub-circulation system is as follows: the first refrigerant vapor enters the first compression cycle condenser (22) from the compressor (21) to condense and heat the generator (2), and forms the first refrigerant liquid; The first refrigerant liquid enters the second compression cycle condenser (23) from the first compression cycle condenser (22) to be condensed, so that the absorption cycle low-pressure stage evaporator (4) is heated and forms the second refrigerant liquid; The second refrigerant liquid enters the compression cycle evaporator (25) from the second compression cycle condenser (23) through the first throttle valve (24) and absorbs heat from the low-grade heat source and / or waste heat and / or heat from the absorption cycle condenser (3) to form a second refrigerant vapor; The second refrigerant vapor is compressed by the compressor (21) from the compression cycle evaporator (25) to generate the first refrigerant vapor, and enters the first compression cycle condenser (22); The working method of the two-stage absorption heat pump subcirculation system is as follows: the solution of the generator (2) enters the high-pressure absorber (1) through the solution pump (9) and multiple solution heat recovery devices; The solution releases heat output after absorbing the fifth refrigerant vapor from the high-pressure stage evaporator (6) of the absorption cycle in the high-pressure stage absorber (1); The solution enters the low-pressure absorber (5) from the high-pressure absorber (1) through the second solution heat recovery device (8) and the third throttle valve (11), absorbs the fourth refrigerant vapor from the low-pressure evaporator (4) of the absorption cycle, and then heats the high-pressure evaporator (6) of the absorption cycle; The solution is returned from the low-pressure absorber (5) through the first solution heat recovery device (7) and the second throttle valve (10) to the generator (2), and the solution returned to the generator (2) is the recovered solution; The recovered solution is heated in the generator (2) through the first compression cycle condenser (22) to generate third refrigerant vapor, and the remaining solution then enters the solution pump (9); After the third refrigerant vapor enters the absorption cycle condenser (3) from the generator (2) and is condensed, the compression cycle evaporator (25) is heated to form a third refrigerant liquid. A portion of the third refrigerant liquid enters the absorption cycle low-pressure stage evaporator (4) from the absorption cycle condenser (3) via the first refrigerant pump (12). After a portion of the third refrigerant liquid enters the absorption cycle low-pressure stage evaporator (4), it absorbs heat from the second compression cycle condenser (23) to form a fourth refrigerant vapor, and then enters the low-pressure stage absorber (5). Another portion of the third refrigerant liquid enters the absorption cycle high-pressure stage evaporator (6) from the absorption cycle condenser (3) through the second refrigerant pump (13). After entering the absorption cycle high-pressure stage evaporator (6), the other portion of the third refrigerant liquid absorbs heat from the low-pressure stage absorber (5) to form a fifth refrigerant vapor, and then enters the high-pressure stage absorber (1).

10. The operating method of the two-stage absorption-compression heat pump system according to claim 9, characterized in that: When waste heat is generated, the waste heat is transferred to the compression cycle evaporator (25).

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