Heat pump system

Abstract

The invention relates to the field of heat pump systems, in particular to a heat pump system, and aims to solve the problem that an existing heat pump system is low in heat exchange efficiency. In order to achieve the purpose, the heat pump system comprises a first refrigerant loop, a second refrigerant loop and a third refrigerant loop, and a first compressor, a first intermediate heat exchanger, a first throttling device and an evaporator are sequentially arranged on the first refrigerant loop; a second compressor, a second intermediate heat exchanger, a second throttling device and a first intermediate heat exchanger are sequentially arranged on the second refrigerant loop; a third compressor, a condenser, a third throttling device and a second intermediate heat exchanger are sequentially arranged on the third refrigerant loop; the heat pump system further comprises a first channel structure, a second channel structure and a third channel structure which are connected in series, and the heat pump system is arranged in the mode that the first channel structure can exchange heat with the first intermediate heat exchanger, the second channel structure can exchange heat with the second intermediate heat exchanger, and the third channel structure can exchange heat with the condenser.

Description

Technical Field

[0001] The present invention relates to the field of heat pump systems, and in particular provides a heat pump system. Background Art

[0002] Currently, heat pump systems are commonly used to generate hot water or steam. In traditional heat pump systems, tap water directly exchanges heat with the refrigerant in a high-temperature condenser. For example, tap water at around 20°C may directly exchange heat with the refrigerant in a condenser above 120°C. Due to the large temperature difference between the two (approximately 100°C), this heat exchange process results in relatively large irreversible losses, low heat exchange efficiency, and a low energy efficiency ratio (COP) for the entire system.

[0003] Furthermore, large temperature differences in heat exchange can increase system operating pressure and thermal stress in heat exchanger materials, impacting system reliability and durability. Furthermore, the complexity of system design and operation increases, making system maintenance and management inconvenient.

[0004] Accordingly, the art needs a new heat pump system to solve the above problems. Summary of the Invention

[0005] The present invention aims to solve the above technical problem, that is, to solve the problem of low heat exchange efficiency of the existing heat pump system.

[0006] In a first aspect, the present invention provides a heat pump system, characterized in that the heat pump system includes: a first refrigerant circuit, on which a first compressor, a first intermediate heat exchanger, a first throttling device and an evaporator are provided in sequence; a second refrigerant circuit, on which a second compressor, a second intermediate heat exchanger, a second throttling device and the first intermediate heat exchanger are provided in sequence; a third refrigerant circuit, on which a third compressor, a condenser, a third throttling device and the second intermediate heat exchanger are provided in sequence; the refrigerant in the first refrigerant circuit and the second refrigerant circuit can be heat exchanged through the first intermediate heat exchanger, and the refrigerant in the second refrigerant circuit and the third refrigerant circuit can be heat exchanged through the second intermediate heat exchanger; a first passage structure, a second passage structure and a third passage structure are connected in series, and the heat pump system is configured so that the first passage structure can exchange heat with the first intermediate heat exchanger, the second passage structure can exchange heat with the second intermediate heat exchanger, and the third passage structure can exchange heat with the condenser.

[0007] In an optional technical solution of the above-mentioned heat pump system, the heat pump system also includes a flash tank, which includes a water inlet and a steam outlet. The water outlet end of the third passage structure is connected to the water inlet, and a pressure reducing device is provided between the water outlet end of the third passage structure and the water inlet.

[0008] In an optional technical solution of the above heat pump system, the flash tank further includes a hot water outlet, and the hot water outlet is connected to the water inlet end of the third passage structure.

[0009] In an optional technical solution of the above heat pump system, the heat pump system further includes a first water vapor compressor, and the steam outlet is connected to the inlet of the first water vapor compressor.

[0010] In an optional technical solution of the above heat pump system, the heat pump system further includes a second water vapor compressor, and the outlet of the first water vapor compressor is connected to the inlet of the second water vapor compressor.

[0011] In an optional technical solution of the above-mentioned heat pump system, the outlet of the first water vapor compressor is connected to the inlet of the second water vapor compressor via a connecting pipe, and a water supply port is provided on the connecting pipe.

[0012] In the optional technical solution of the above-mentioned heat pump system, the first intermediate heat exchanger includes a first evaporator tube connected to the second refrigerant circuit and a first condenser tube connected to the first refrigerant circuit, the first evaporator tube and the first passage structure constitute a first shell-and-tube heat exchange structure, and the first condenser tube is mounted on the first shell-and-tube heat exchange structure.

[0013] In the optional technical solution of the above-mentioned heat pump system, the second intermediate heat exchanger includes a second evaporator tube connected to the third refrigerant circuit and a second condenser tube connected to the second refrigerant circuit, the second evaporator tube and the second passage structure constitute a second shell and tube heat exchange structure, and the second condenser tube is sleeved on the second shell and tube heat exchange structure.

[0014] In an optional technical solution of the above heat pump system, the heat pump system further includes a first water pump, which is used to pump water from the first passage structure to the third passage structure.

[0015] In an optional technical solution of the above-mentioned heat pump system, the hot water outlet and the water inlet end of the third passage structure are connected by a return pipe, and a second water pump is provided on the return pipe. The second water pump is used to pump water from the hot water outlet toward the water inlet end of the third passage structure.

[0016] The aforementioned heat pump system achieves a staged heating of the water, significantly reducing the heat exchange temperature difference between the refrigerant and the water during the heating process, optimizing heat exchange efficiency and reducing energy losses, thereby significantly improving the energy efficiency of the entire heat pump system. This hierarchical design allows the heat pump system to more efficiently utilize low-grade heat sources to provide the required high-temperature hot water. This is particularly suitable for industrial or commercial heat recovery, high-temperature hot water supply, or steam generation, which is of great significance for energy conservation, emission reduction, and sustainable development. Furthermore, this hierarchical design improves the system's reliability and durability, facilitating maintenance and management. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0018] Figure 1 1 is a schematic structural diagram of the heat pump system of the present invention (I);

[0019] Figure 2 Schematic diagram of the heat pump system of the present invention (II);

[0020] Figure 3 Schematic diagram (1) of a heat exchange structure composed of a first intermediate heat exchanger and a first passage structure of a heat pump system of the present invention;

[0021] Figure 4 Schematic diagram (2) of the heat exchange structure composed of the first intermediate heat exchanger and the first passage structure of the heat pump system of the present invention.

[0022] Description of reference numerals:

[0023] 10-first refrigerant circuit; 11-first compressor; 12-first intermediate heat exchanger; 121-first evaporator; 1211-third through hole; 1212-fourth through hole; 122-first condenser; 1221-first through hole; 1222-second through hole; 1223-fifth through hole; 1224-sixth through hole; 13-first throttling device; 14-evaporator; 20-second refrigerant circuit; 21-second compressor; 22-second intermediate heat exchanger; 23-second throttling device; 30-third refrigerant circuit; 31-third compressor Machine; 32-condenser; 33-third throttling device; 40-first passage structure; 41-second passage structure; 42-third passage structure; 43-first water pipe; 44-second water pipe; 45-third water pipe; 46-fourth water pipe; 47-first water pump; 50-flash tank; 501-water inlet; 502-steam outlet; 503-hot water outlet; 51-pressure reducing device; 52-second water pump; 53-return pipe; 60-first water vapor compressor; 61-second water vapor compressor; 62-connecting pipe; 621-water supply port. DETAILED DESCRIPTION

[0024] Preferred embodiments of the present invention are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely intended to illustrate the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. Those skilled in the art may adjust these embodiments as needed to suit specific applications.

[0025] It should be noted that, in the description of the present invention, the terms "first", "second" and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0026] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0027] In order to solve the problem of low heat exchange efficiency of the existing heat pump system, the present invention provides a heat pump system, such as Figure 1 As shown, the heat pump system includes a first refrigerant circuit 10, a second refrigerant circuit 20 and a third refrigerant circuit 30. The first refrigerant circuit 10 is provided with a first compressor 11, a first intermediate heat exchanger 12, a first throttling device 13 and an evaporator 14 in sequence. The second refrigerant circuit 20 is provided with a second compressor 21, a second intermediate heat exchanger 22, a second throttling device 23 and the first intermediate heat exchanger 12 in sequence. The third refrigerant circuit 30 is provided with a third compressor 31, a condenser 32, a third throttling device 33 and the second intermediate heat exchanger 22 in sequence. The refrigerant in the circuit 10 and the second refrigerant circuit 20 can exchange heat through the first intermediate heat exchanger 12, and the refrigerant in the second refrigerant circuit 20 and the third refrigerant circuit 30 can exchange heat through the second intermediate heat exchanger 22; the heat pump system also includes a first passage structure 40, a second passage structure 41, and a third passage structure 42 connected in series. The heat pump system is configured so that the first passage structure 40 can exchange heat with the first intermediate heat exchanger 12, the second passage structure 41 can exchange heat with the second intermediate heat exchanger 22, and the third passage structure 42 can exchange heat with the condenser 32. The present invention does not impose any restrictions on the specific structural form of the first throttling device 13, the second throttling device 23, and the third throttling device 33, as long as they can perform throttling and pressure reduction, such as a capillary tube or an electronic expansion valve.

[0028] It is understandable that the above-mentioned refrigerant circuit refers to a physical structure constituting the circuit, that is, a refrigerant circulation pipe. In addition, it is understandable that water can be passed into the passage structure introduced above, and other fluids that can be heated can also be passed into the passage structure. For the sake of convenience, the following will be introduced by taking the example of passing water into the passage structure. Among them, the passage structure refers to a passage structure with a water inlet end and a water outlet end. Water can enter the passage structure from the water inlet end and flow out from the water outlet end. The present invention does not limit the specific form of the passage structure. As long as it can pass water, its specific form can be adjusted. For example, the passage structure can be a straight tube, a coil, or a structure in which a water channel is set in the shell, etc. These adjustments do not deviate from the principle of the present invention and are within the protection scope of the present invention.

[0029] The heat pump system adopts a three-stage cascade cycle. In the first refrigerant circuit 10, the refrigerant in the evaporator 14 takes heat from the environment (air source, water source, etc.). The following is an introduction based on an ambient temperature of about 20°C. The refrigerant after taking heat enters the first compressor 11 for compression and temperature increase, and then enters the first intermediate heat exchanger 12. Here, the refrigerant exchanges heat with the water in the first passage structure 40 and the refrigerant in the second refrigerant circuit 20, transferring heat to the water in the first passage structure 40 and the refrigerant in the second refrigerant circuit 20, raising the water temperature to about 60°C. The refrigerant then flows to the first throttling device 13. After flowing through the first throttling device 13, the pressure decreases and it absorbs heat in the evaporator 14, completing the primary cycle. In the second refrigerant circuit 20, after being compressed by the second compressor 21, the refrigerant is also heated and flows to the second intermediate heat exchanger 22. At this time, more heat is transferred to the water in the second path structure 41 and the refrigerant in the third refrigerant circuit 30, raising the water temperature to approximately 90°C. The refrigerant then flows to the second throttling device 23. After flowing through the second throttling device 23, the pressure is reduced. It absorbs heat in the first intermediate heat exchanger 12, completing the secondary cycle. In the third refrigerant circuit 30, the refrigerant is compressed by the third compressor 31, rising to the maximum temperature. Then, in the condenser 32, the heat is transferred to the water in the third path structure 42. At this time, the water temperature can reach approximately 120°C. The refrigerant then flows to the third throttling device 33. After flowing through the third throttling device 33, the pressure is reduced. It absorbs heat in the second intermediate heat exchanger 22, completing the tertiary cycle. The heat pump system of the present invention achieves graded water heating, significantly reducing the heat exchange temperature difference between the refrigerant and the water during the heating process, optimizing heat exchange efficiency and reducing energy losses, thereby significantly improving the energy efficiency of the entire heat pump system. Through this graded design, the heat pump system can more efficiently utilize low-grade heat sources to provide the required high-temperature hot water. This is particularly suitable for industrial or commercial heat recovery, high-temperature hot water supply, or steam generation, which is of great significance for energy conservation, emission reduction, and sustainable development. Furthermore, this graded design can improve the reliability and durability of the system, facilitating maintenance and management.

[0030] As a possible embodiment, the heat pump system of the present invention also includes a flash tank 50, which includes a water inlet 501, a steam outlet 502 and a hot water outlet 503. The water outlet end of the third passage structure 42 is connected to the water inlet 501, and a pressure reducing device 51 is provided between the water outlet end of the third passage structure 42 and the water inlet 501.

[0031] Possibly, the heat pump system includes a first water pipe 43, a second water pipe 44, a third water pipe 45, and a fourth water pipe 46. The water outlet of the first water pipe 43 is connected to the water inlet of the first passage structure 40. The water outlet of the first passage structure 40 is connected to the water inlet of the second passage structure 41 via the second water pipe 44. The water outlet of the second passage structure 41 is connected to the water inlet of the third passage structure 42 via the third water pipe 45. The water outlet of the third passage structure 42 is connected to the water inlet 501 via the fourth water pipe 46. Of course, the above is merely exemplary, and at least one of the first water pipe 43, the second water pipe 44, the third water pipe 45, and the fourth water pipe 46 may be omitted. The pressure reducing device 51 may be provided on the fourth water pipe 46, or may be directly connected to the water outlet of the third passage structure 42 and the water inlet 501. The pressure reducing device 51 may specifically be a pressure reducing valve, an expansion valve, or a pressure regulating valve, etc. When hot water at 120°C is decompressed by the decompression device 51 and enters the flash tank 50 through the water inlet 501, the pressure inside the tank is lower than the saturated vapor pressure of water at 120°C, and the water will be partially converted into steam, thereby producing water vapor at about 120°C.

[0032] As one possible embodiment, the hot water outlet 503 of the flash tank 50 is connected to the water inlet of the third passage structure 42. For example, the hot water outlet 503 and the water inlet of the third passage structure 42 are connected via a return pipe 53. Specifically, the water outlet of the return pipe 53 can be indirectly connected to the water inlet of the third passage structure 42 via a third water pipe 45. Of course, the water outlet of the return pipe 53 can also be directly connected to the water inlet of the third passage structure 42. These adjustments do not deviate from the principles of the present invention and are within the scope of protection of the present invention.

[0033] Optionally, a second water pump 52 is provided on the water return pipe 53, and the second water pump 52 is used to pump water from the hot water outlet 503 toward the water inlet of the third passage structure 42. For example, the water return pipe 53 includes a first water return section and a second water return section, wherein one end of the first water return section is connected to the hot water outlet 503, and the other end of the first water return section is connected to the water inlet of the second water pump 52; one end of the second water return section is connected to the water outlet of the second water pump 52, and the other end of the second water return section is connected to the water inlet of the third passage structure 42. Of course, the above is only exemplary. As long as the second water pump 52 can pump water from the hot water outlet 503 to the water inlet end of the third passage structure 42, its specific setting method can be adjusted. For example, the setting of the first return water section can be omitted, and the water inlet of the second water pump 52 is directly connected to the hot water outlet 503 of the flash tank 50, or the setting of the second return water section can be omitted, and the water outlet of the second water pump 52 is directly connected to the water inlet end of the third passage structure 42, etc. These adjustments do not deviate from the principles of the present invention and are within the scope of protection of the present invention.

[0034] By connecting the hot water outlet 503 of the flash tank 50 to the water inlet of the third passage structure 42, the heat pump system can recover some heat energy. This waste heat from the flash tank 50 can be used to raise the water inlet temperature of the third passage structure 42, further reducing the heat exchange temperature difference and improving heat exchange efficiency. Furthermore, this configuration provides an additional control point, allowing the speed of the second water pump 52, and thus the water inlet temperature of the third passage structure 42, to be adjusted according to the actual operating conditions of the system, increasing the flexibility of system design.

[0035] As a possible embodiment, the heat pump system further includes a first water pump 47, which is used to pump water from the first passage structure 40 to the third passage structure 42. The present invention does not limit the location of the first water pump 47. For example, the first water pump 47 may be located on the first water pipe 43, or on one of the second water pipe 44, the third water pipe 45, or the fourth water pipe 46. Adjustments to these locations do not deviate from the principles of the present invention and are within the scope of protection of the present invention.

[0036] As a possible embodiment, the heat pump system further includes a first water vapor compressor 60, and the steam outlet 502 is connected to the inlet of the first water vapor compressor 60. The first water vapor compressor 60 increases the thermal energy level of the steam by increasing the pressure and temperature of the steam, so that the steam temperature can be raised to above 120°C.

[0037] As a possible implementation, Figure 2 As shown, the heat pump system further includes a second water vapor compressor 61 , and the outlet of the first water vapor compressor 60 is connected to the inlet of the second water vapor compressor 61 .

[0038] Connecting the outlet of the first steam compressor 60 to the inlet of the second steam compressor 61 forms a two-stage compression system. This configuration has the following advantages: Two-stage compression can more efficiently increase the temperature and pressure of the steam, thereby improving the thermal efficiency of the entire system. The steam temperature after passing through the second steam compressor 61 can reach 160°C. Two-stage compression requires less power than single-stage compression because the total power consumption required to compress the steam to the same final pressure is less, thus achieving energy savings. A two-stage compression system can smooth the compression process, reduce pressure pulses and thermal stress in the system, and thus enhance system stability and reliability.

[0039] Furthermore, the outlet of the first water vapor compressor 60 is connected to the inlet of the second water vapor compressor 61 via a connecting pipe 62, and the connecting pipe 62 is provided with a water supply port 621. A water supply pipe may be provided to connect the water supply port 621 to facilitate drainage.

[0040] A water supply port 621 is provided between the two compression stages. The added cold water lowers the temperature of the gas at the inlet of the second water vapor compressor 61, thereby improving compression efficiency. This is because the compressor requires less energy to process low-temperature gas than to process high-temperature gas. During the high-temperature steam compression stage, if the water vapor overheats, it may damage the mechanical components of the compressor. Water supply helps control the steam temperature and reduce the risk of overheating.

[0041] The heat exchange structure formed by the first intermediate heat exchanger 12 and the first passage structure 40 is described below. Figure 3 and Figure 4 As shown, as a possible embodiment, the first intermediate heat exchanger 12 includes a first evaporator tube 121 connected to the second refrigerant circuit 20 and a first condenser tube 122 connected to the first refrigerant circuit 10. The first evaporator tube 121 and the first passage structure 40 constitute a first shell and tube heat exchange structure, and the first condenser tube 122 is mounted on the first shell and tube heat exchange structure.

[0042] The first evaporator tube 121 and the first passage structure 40 are arranged as the cold end on the inner side of the first condenser tube 122, and the first condenser tube 122 is arranged as the hot end on the outermost side. This can optimize the temperature difference, which is beneficial to improving the driving force of heat exchange. It can enable the refrigerant in the first evaporator tube 121 and the water in the first passage structure 40 to effectively absorb the heat released by the refrigerant in the outer first condenser tube 122, thereby reducing heat loss. The arrangement of the two cold ends being arranged on the inside and the hot end being arranged on the outside can also reduce the circulation of heat in different parts, which is beneficial to maintaining the stability and reliability of the system. In addition, since the cold end is on the inside, the temperature of the hot end on the outside will not be too high, which reduces the thermal stress of the hot end components and reduces the risk of leakage caused by temperature changes.

[0043] Possibly, refer to Figure 3, the first evaporation tube 121 can be sleeved on the outside of the first passage structure 40, and the first condensation tube 122 can be sleeved on the outside of the first evaporation tube 121. In order to facilitate connection, a first through hole 1221 and a second through hole 1222 can be set on the side wall of the first condensation tube 122, and a third through hole 1211 can be set on the side wall of the first evaporation tube 121. The end of the first passage structure 40 is sealed through the third through hole 1211 and the first through hole 1221, so that the end is connected in series with other passage structures. The end of the first evaporation tube 121 is sealed through the second through hole 1222, so that the end of the first evaporation tube 121 is connected to the first refrigerant circuit 10, and the end of the first condensation tube 122 can be directly connected to the first refrigerant circuit 10. The ends of the first condensation tube 122, the first evaporation tube 121 and the first passage structure 40 described above can be ends located on the same side, and the ends on the other side can also be connected based on the method described above. Of course, the above description is only one possible implementation method. In actual applications, its structure can be adjusted. For example, refer to Figure 4 The ends of the first evaporation tube 121 and the first condensation tube 122 are sealed, a fourth through-hole 1212 is provided on the side of the first evaporation tube 121, and a fifth through-hole 1223 and a sixth through-hole 1224 are provided on the side of the first condensation tube 122. The first passage structure 40 sequentially seals and passes through the ends of the first evaporation tube 121 and the first condensation tube 122. The fourth through-hole 1212 and the fifth through-hole 1223 are connected by a tube, and the sixth through-hole 1224 serves as a refrigerant inlet or outlet. These adjustments do not deviate from the principles of the present invention and are within the scope of protection of the present invention. Alternatively, the first passage structure 40 can be sleeved on the outside of the first evaporation tube 121, and the first condensation tube 122 can be sleeved on the outside of the first passage structure 40.

[0044] The following describes the heat exchange structure formed by the second intermediate heat exchanger 22 and the second passage structure 41. As one possible embodiment, the second intermediate heat exchanger 22 includes a second evaporator tube connected to the third refrigerant circuit 30 and a second condenser tube connected to the second refrigerant circuit 20. The second evaporator tube and the second passage structure 41 form a second double-tube heat exchange structure, and the second condenser tube is sleeved within the second double-tube heat exchange structure. The specific configuration and advantages described above are similar to those of the connection structure between the first intermediate heat exchanger 12 and the first condenser tube 122 and will not be further described.

[0045] The heat exchange structure formed by the third passage structure 42 and the condenser 32 is described below. The specific heat exchange structure for the third passage structure 42 and the condenser 32 may be a shell-and-tube heat exchanger or a plate heat exchanger, etc. As long as heat exchange between the third passage structure 42 and the condenser 32 is achieved, the present invention does not limit the specific form thereof. Adjustments to these specific forms do not deviate from the principles of the present invention and are within the scope of protection of the present invention.

[0046] It should be noted that the above-mentioned embodiments are only used to illustrate the principles of the present invention and are not intended to limit the scope of protection of the present invention. Without departing from the principles of the present invention, those skilled in the art can adjust the above-mentioned structure so that the present invention can be applied to more specific application scenarios.

[0047] For example, as an alternative embodiment, although the first intermediate heat exchanger 12 and the first passage structure 40 of the present invention are introduced as a shell-and-tube structure, this is not intended to limit the scope of protection of the present invention. As long as the heat exchange between the first passage structure 40 and the first intermediate heat exchanger 12 can be achieved, the specific form can be adjusted. For example, a plate heat exchanger, a microchannel heat exchanger or a spiral heat exchanger, etc. are formed between the first intermediate heat exchanger 12 and the first passage structure 40. These adjustments do not deviate from the principles of the present invention and are within the scope of protection of the present invention.

[0048] For example, as an alternative embodiment, although the second intermediate heat exchanger 22 and the second path structure 41 of the present invention are introduced as a shell-and-tube structure, this is not intended to limit the scope of protection of the present invention. As long as the heat exchange between the second path structure 41 and the second intermediate heat exchanger 22 can be achieved, the specific form can be adjusted. For example, the second intermediate heat exchanger 22 and the second path structure 41 constitute a plate heat exchanger, a microchannel heat exchanger or a spiral heat exchanger, etc. These adjustments do not deviate from the principles of the present invention and are within the scope of protection of the present invention.

[0049] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A heat pump system, characterized in that: The heat pump system comprises: a first refrigerant circuit, wherein a first compressor, a first intermediate heat exchanger, a first throttling device, and an evaporator are sequentially provided on the first refrigerant circuit; a second refrigerant circuit, wherein a second compressor, a second intermediate heat exchanger, a second throttling device and the first intermediate heat exchanger are sequentially provided on the second refrigerant circuit; a third refrigerant circuit, wherein the third compressor, the condenser, the third throttling device and the second intermediate heat exchanger are sequentially provided on the third refrigerant circuit; The refrigerants in the first refrigerant circuit and the second refrigerant circuit can exchange heat through the first intermediate heat exchanger, and the refrigerants in the second refrigerant circuit and the third refrigerant circuit can exchange heat through the second intermediate heat exchanger; The first passage structure, the second passage structure and the third passage structure are connected in series, and the heat pump system is configured so that the first passage structure can exchange heat with the first intermediate heat exchanger, the second passage structure can exchange heat with the second intermediate heat exchanger, and the third passage structure can exchange heat with the condenser.

2. The heat pump system according to claim 1, characterized in that The heat pump system further includes a flash tank including a water inlet and a steam outlet. The water outlet of the third passage structure is connected to the water inlet. A pressure reducing device is provided between the water outlet of the third passage structure and the water inlet.

3. The heat pump system according to claim 2, characterized in that The flash tank further includes a hot water outlet, which is connected to the water inlet end of the third passage structure.

4. The heat pump system according to claim 2, characterized in that The heat pump system further includes a first water vapor compressor, and the steam outlet is connected to the inlet of the first water vapor compressor.

5. The heat pump system according to claim 4, characterized in that The heat pump system further includes a second water vapor compressor, and an outlet of the first water vapor compressor is connected to an inlet of the second water vapor compressor.

6. The heat pump system according to claim 5, characterized in that The outlet of the first water vapor compressor is connected to the inlet of the second water vapor compressor via a connecting pipe, and a water supply port is provided on the connecting pipe.

7. The heat pump system according to claim 1, characterized in that The first intermediate heat exchanger includes a first evaporator tube connected to the second refrigerant circuit and a first condenser tube connected to the first refrigerant circuit. The first evaporator tube and the first passage structure constitute a first shell-and-tube heat exchange structure, and the first condenser tube is mounted on the first shell-and-tube heat exchange structure.

8. The heat pump system according to claim 1, wherein: The second intermediate heat exchanger includes a second evaporator tube connected to the third refrigerant circuit and a second condenser tube connected to the second refrigerant circuit. The second evaporator tube and the second passage structure constitute a second shell and tube heat exchange structure, and the second condenser tube is mounted on the second shell and tube heat exchange structure.

9. The heat pump system according to claim 1, characterized in that The heat pump system further includes a first water pump, which is used to pump water from the first passage structure to the third passage structure.

10. The heat pump system according to claim 3, characterized in that The hot water outlet is connected to the water inlet of the third passage structure through a return pipe. A second water pump is provided on the return pipe. The second water pump is used to pump water from the hot water outlet to the water inlet of the third passage structure.

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