Heat pump system

Abstract

The invention relates to a heat pump system, 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 when the required temperature of heat supply fluid is high. In order to achieve the purpose, the heat pump system comprises a first refrigerant loop, a second refrigerant loop and an inflow path structure, and a first compressor, a first heat exchanger, a first throttling device and an evaporator are sequentially arranged on the first refrigerant loop; a second compressor, a second heat exchanger, a second throttling device and a first heat exchanger are sequentially arranged on the second refrigerant loop; the second heat exchanger is further arranged on the inflow path structure. A refrigerant in the first refrigerant loop and a refrigerant in the second refrigerant loop can exchange heat through the first heat exchanger; refrigerant in the second refrigerant loop and fluid in the inflow path structure can exchange heat through the second heat exchanger. A refrigerant in the first refrigerant loop is a transcritical refrigerant, and a refrigerant in the second refrigerant loop is a mixed refrigerant.

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] When the heating fluid has a wide temperature range, such as when ambient temperature water is heated to 80-90°C or above for process heating, or when tap water is heated to steam for industrial steam production, the temperature rise of the heating fluid water is significant.

[0003] For high-temperature hot water applications, there are currently single-stage CO2 systems. However, due to the limited compression ratio of the compressor, the heating temperature span is small. That is, when the ambient temperature drops to a certain level (such as -10°C), the heating temperature cannot be met (for example, the heating temperature is less than 80°C). To address this issue, there are cascade systems that use a CO2 system as the low-temperature stage and R134a as the high-temperature stage. However, there is a large temperature difference between the R134a subcritical cycle constant-temperature condensation heat exchange and the heating fluid (water), resulting in low system efficiency.

[0004] For high-temperature steam applications, the currently used technology is multi-stage cascade technology, with R32 or R410a as the low-temperature working fluid, R134a as the medium-temperature working fluid, and R245fa as the high-temperature working fluid. These working fluids all utilize subcritical cycles for constant-temperature condensation heat exchange, resulting in large temperature differences and low system efficiency.

[0005] Accordingly, the art needs a new heat pump system to solve the above problems. Summary of the Invention

[0006] The present invention aims to solve the above technical problem, namely, to solve the problem that the existing heat pump system has low heat exchange efficiency when the required temperature of the heating fluid is high.

[0007] 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 heat exchanger, a first throttling device and an evaporator are provided in sequence; a second refrigerant circuit, on which a second compressor, a second heat exchanger, a second throttling device and the first heat exchanger are provided in sequence; an inlet passage structure, on which the second heat exchanger is also provided; the refrigerant in the first refrigerant circuit and the refrigerant in the second refrigerant circuit can exchange heat through the first heat exchanger; the refrigerant in the second refrigerant circuit and the fluid in the inlet passage structure can exchange heat through the second heat exchanger; the refrigerant in the first refrigerant circuit is a transcritical refrigerant, and the refrigerant in the second refrigerant circuit is a mixed refrigerant.

[0008] In an optional technical solution of the above-mentioned heat pump system, the first heat exchanger is also arranged on the inlet passage structure so that the fluid in the inlet passage structure can exchange heat through the first heat exchanger, and the first heat exchanger and the second heat exchanger are arranged in sequence in the direction from the inlet to the outlet of the inlet passage structure.

[0009] In an optional technical solution of the above-mentioned heat pump system, the second heat exchanger is also arranged on the refrigerant pipe section between the first heat exchanger and the suction port side of the second compressor, so that the refrigerant in the refrigerant pipe section can exchange heat through the second heat exchanger.

[0010] In an optional technical solution of the above-mentioned heat pump system, the heat pump system further includes a flash tank and a reflux passage structure, the outlet of the inlet passage structure is connected to the water inlet of the flash tank, and the hot water outlet of the flash tank is connected to the reflux passage structure; the first heat exchanger is also provided on the reflux passage structure so that the fluid in the reflux passage structure can exchange heat through the first heat exchanger, and / or the second heat exchanger is also provided on the reflux passage structure so that the fluid in the reflux passage structure can exchange heat through the second heat exchanger.

[0011] In an optional technical solution of the above-mentioned heat pump system, the heat pump system also includes a water storage device, which includes a water inlet and a water outlet. The water outlet end of the reflux passage structure is connected to the water inlet, and the water outlet is connected to the inlet of the inlet passage structure.

[0012] In the optional technical solution of the above-mentioned heat pump system, the heat pump system also includes a first water replenishment passage structure and a heat source passage structure. The first water replenishment passage structure can exchange heat with the heat source passage structure, and the water outlet end of the first water replenishment passage structure is connected to the inlet of the inlet passage structure.

[0013] In an optional technical solution of the above heat pump system, the heat source passage structure is capable of exchanging heat with the evaporator.

[0014] In an optional technical solution of the above-mentioned heat pump system, the heat pump system further includes a second water replenishment passage structure, and a water outlet end of the second water replenishment passage structure is connected to the inlet of the inlet passage structure.

[0015] In an optional technical solution of the above-mentioned heat pump system, the heat pump system further includes a water pump, and the water pump is provided on the inlet passage structure or the return passage structure.

[0016] In an optional technical solution of the above heat pump system, a pressure reducing device is provided on the inlet passage structure on the water inlet side of the flash tank.

[0017] When the above technical solution is adopted, since the refrigerant in the first refrigerant circuit is a transcritical refrigerant and the refrigerant in the second refrigerant circuit is a mixed refrigerant, the transcritical evaporation side constant temperature phase change of the first refrigerant circuit is used to reduce the heat exchange temperature difference with the environment (usually the temperature is constant), and the temperature glide characteristics of the transcritical condensation side (heat release side) are used to reduce the heat exchange temperature difference with water, and the temperature glide characteristics of the transcritical condensation side (heat release side) are used to match the temperature glide characteristics of the mixed refrigerant on the evaporation side of the second refrigerant circuit to reduce the heat exchange temperature difference; the evaporation side of the second refrigerant circuit uses its temperature glide characteristics to match the temperature glide characteristics of the transcritical cycle heat release side to reduce the evaporation heat absorption heat exchange temperature difference, while the condensation side uses the temperature glide characteristics of the condensation process to exchange heat with the heat supply fluid in the inlet flow path structure to reduce the heat exchange temperature difference, so that the heat supply fluid is heated to the required temperature. In this way, for the two refrigeration cycles, whether on the evaporation side or the heat release side, the heat exchange temperature difference can be reduced, thereby greatly improving the efficiency of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0019] Figure 1 It is a structural diagram of the heat pump system in the hot water scenario;

[0020] Figure 2 It is a structural diagram of the heat pump system in the high-temperature steam scenario;

[0021] Figure 3 This is a schematic diagram of a first possible structure of the first heat exchanger and the second heat exchanger in a hot water scenario;

[0022] Figure 4 1 is a schematic diagram of a second possible structure of the first heat exchanger and the second heat exchanger in the hot water scenario;

[0023] Figure 5 This is a schematic diagram of the third possible structure of the first heat exchanger and the second heat exchanger in the hot water scenario;

[0024] Figure 6 This is a schematic diagram of the first possible structure of the first heat exchanger and the second heat exchanger in the high-temperature steam scenario;

[0025] Figure 7 This is a second possible structural diagram of the first heat exchanger and the second heat exchanger in the high-temperature steam scenario.

[0026] Description of reference numerals:

[0027] 10-first refrigerant circuit; 11-first compressor; 12-first throttling device; 13-evaporator; 20-second refrigerant circuit; 21-second compressor; 22-second throttling device; 30-inlet passage structure; 31-return passage structure; 40-first heat exchanger; 401-first outer tube shell; 402-first tube bundle; 403-second tube bundle; 404-second outer tube shell; 405-first inner tube shell; 406-third tube bundle; 407-third outer tube shell; 408-fourth tube bundle; 409-fifth tube bundle; 410-second inner tube shell; 41-second heat exchanger; 50-flash tank; 51-water storage device; 60-first water supply passage structure; 61-heat source passage structure; 611-heat exchange cavity; 62-second water supply passage structure; 70-water pump; 71-pressure reducing device. DETAILED DESCRIPTION

[0028] 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.

[0029] 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.

[0030] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "installed," "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, such as through a water pipe; and internal connections 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.

[0031] In order to solve the problem of low heat exchange efficiency in existing heat pump systems when the required temperature of the heating fluid is high, the present invention provides a heat pump system, such as Figure 1As shown, the heat pump system includes a first refrigerant circuit 10, a second refrigerant circuit 20, a first compressor 11, a first heat exchanger 40, a first throttling device 12, an evaporator 13, a second compressor 21, a second heat exchanger 41, a second throttling device 22 and an inlet passage structure 30. The first compressor 11, the first heat exchanger 40, the first throttling device 12 and the evaporator 13 are arranged in sequence on the first refrigerant circuit 10, and the second compressor 21, the second heat exchanger 41, the second throttling device 22 and the first heat exchanger 40 are arranged in sequence on the second refrigerant circuit 20. The second heat exchanger 41 is also arranged on the inlet passage structure 30. The refrigerant in the first refrigerant circuit 10 and the refrigerant in the second refrigerant circuit 20 can exchange heat through the first heat exchanger 40; the refrigerant in the second refrigerant circuit 20 and the fluid in the inlet passage structure 30 can exchange heat through the second heat exchanger 41. The refrigerant in the first refrigerant circuit 10 is a transcritical refrigerant, and the refrigerant in the second refrigerant circuit 20 is a mixed refrigerant. The present invention does not limit the specific structural form of the first throttling device 12 and the second throttling device 22, as long as they can throttle and reduce pressure, such as a capillary tube or an electronic expansion valve. The inlet flow path structure 30 is a pipe structure or a microchannel structure having a water inlet and a water outlet.

[0032] Since the refrigerant in the first refrigerant circuit 10 is a transcritical refrigerant and the refrigerant in the second refrigerant circuit 20 is a mixed refrigerant, the transcritical evaporation side constant temperature phase change of the first refrigerant circuit 10 is used to reduce the heat exchange temperature difference with the environment (usually the temperature is constant), and the temperature glide characteristics of the transcritical condensation side (heat release side) are matched with the temperature glide characteristics of the mixed refrigerant on the evaporation side of the second refrigerant circuit 20 to reduce the heat exchange temperature difference; the evaporation side of the second refrigerant circuit 20 uses its temperature glide characteristics to match the temperature glide characteristics of the transcritical cycle heat release side to reduce the evaporation heat absorption heat exchange temperature difference, while the condensation side uses the temperature glide characteristics of the condensation process to exchange heat with the heat supply fluid in the inlet flow path structure 30 to reduce the heat exchange temperature difference, so that the heat supply fluid is heated to the required temperature. In this way, for both refrigeration cycles, the heat exchange temperature difference can be reduced on both the evaporation side and the heat release side, thereby greatly improving the efficiency of the entire system. Among them, the heat supply fluid in the above-mentioned inlet flow path structure 30 can be water or other heatable fluids. For the sake of convenience, water will be used as an example below.

[0033] As a possible embodiment, the first heat exchanger 40 is also provided on the inlet passage structure 30 so that the fluid in the inlet passage structure 30 can be heat exchanged through the first heat exchanger 40. The first heat exchanger 40 and the second heat exchanger 41 are arranged in sequence in the direction from the inlet to the outlet of the inlet passage structure 30. That is, water flows from the inlet of the inlet passage structure 30 through the first heat exchanger 40 and the second heat exchanger 41 in sequence for heat exchange and then flows out from the outlet of the inlet passage structure 30.

[0034] In this case, the temperature glide characteristics of the transcritical cycle condensation side of the first refrigerant circuit 10 are used to reduce the heat exchange temperature difference with the water, so that the water is heated initially. Then the mixed refrigerant in the second refrigerant circuit 20 uses the temperature glide characteristics to exchange heat with the water on the condensation side to reduce the heat exchange temperature difference. As a result, the heat exchange temperature difference can be reduced throughout the entire process of water heating, greatly improving the efficiency of the system.

[0035] As a possible embodiment, the second heat exchanger 41 is also arranged on the refrigerant pipe section between the first heat exchanger 40 and the suction port side of the second compressor 21, so that the refrigerant in the refrigerant pipe section between the first heat exchanger 40 and the suction port side of the second compressor 21 can be heat exchanged through the second heat exchanger 41, thereby preheating the refrigerant on the suction port side of the second compressor 21, increasing the temperature on the exhaust port side of the second compressor 21, and allowing the high-temperature refrigerant to enter the second heat exchanger 41, thereby increasing the heating temperature of the water.

[0036] For the above hot water scenario, the working process is as follows:

[0037] In the first refrigerant circuit 10, the refrigerant cycle is a transcritical cycle (the working fluid is a single-component pure working fluid such as CO2, R290, etc.). The refrigerant takes heat from the environment in the evaporator 13 and enters the first compressor 11 for compression. Then, the first heat exchanger 40 provides the required heat for the water and the mixed refrigerant in the second refrigerant circuit 20. The pure refrigerant after heat exchange is reduced in pressure and temperature by the first throttling device 12 and then enters the evaporator 13 to absorb heat to complete the transcritical refrigeration cycle (the operating pressure is higher than the critical pressure of the working fluid).

[0038] In the second refrigerant circuit 20, the refrigerant cycle is a heat recovery cycle of the mixed refrigerant. After being compressed by the second compressor 21, the refrigerant enters the second heat exchanger 41 to provide the required heat for further heating of the water and heat recovery of its own low-pressure mixed refrigerant. Then, it enters the second throttling device 22 to reduce the pressure and temperature, and then absorbs the heat released by the refrigerant in the transcritical cycle in the first heat exchanger 40. Then, it enters the second heat exchanger 41 to perform heat recovery exchange with the high-temperature and high-pressure mixed refrigerant, and then enters the second compressor 21 to complete the heat recovery cycle of the mixed refrigerant.

[0039] For water fluid, cold water is heated by the high-temperature side transcritical cycle refrigerant in the first heat exchanger 40 and is heated by the high-temperature side mixed refrigerant in the second heat exchanger 41, and finally reaches the required high temperature state.

[0040] As a possible implementation, the heat pump system of the present invention can also be used in high-temperature steam scenarios. In this case, Figure 2As shown, the heat pump system also includes a flash tank 50 and a reflux passage structure 31. The outlet of the inlet passage structure 30 is connected to the water inlet of the flash tank 50, and the hot water outlet of the flash tank 50 is connected to the reflux passage structure 31. A first heat exchanger 40 and a second heat exchanger 41 are also disposed on the reflux passage structure 31, so that the fluid in the reflux passage structure 31 can exchange heat with the first heat exchanger 40 through the second heat exchanger 41. Furthermore, a pressure reducing device 71 can be disposed on the inlet passage structure 30 on the water inlet side of the flash tank 50. The pressure reducing device 71 can specifically be a pressure reducing valve, an expansion valve, or a pressure regulating valve. A water pump 70 may be disposed on the inlet passage structure 30 or the reflux passage structure 31. Specifically, the water pump 70 may be disposed on the inlet passage structure 30 upstream of the first heat exchanger 40, or on the reflux passage structure 31 between the flash tank 50 and the second heat exchanger 41.

[0041] The above-mentioned setting method enables, under the action of the water pump 70, the high-temperature water heated by the second heat exchanger 41 to be reduced in pressure through the pressure reducing device 71, enters the flash tank 50 from the water inlet, is partially converted into high-temperature steam and flows out from the steam outlet of the flash tank 50, and the generated hot water enters the reflux path structure 31 from the hot water outlet, and flows into the second heat exchanger 41 to heat the water in the inlet path structure 30 and the low-pressure mixed refrigerant in the second refrigerant circuit 20, and then enters the first heat exchanger 40 to heat the water in the hot inlet path structure 30 and the mixed refrigerant on the evaporation side of the second refrigerant circuit 20, thereby further reducing the heat exchange temperature difference and improving efficiency.

[0042] As a possible embodiment, the heat pump system also includes a water storage device 51, which includes a water inlet and a water outlet. The water outlet end of the reflux passage structure 31 is connected to the water inlet, and the water outlet is connected to the inlet of the inlet passage structure 30, thereby forming a closed water circulation loop. Among them, the flash tank 50 is used to evaporate a part of the water by quickly reducing the water pressure in order to perform heat exchange. This process will cause the water pressure in the water circulation loop to drop. The water storage device 51 can replenish the water flow after this process to ensure the stability of the water pressure and allow the system to operate smoothly. The water storage device 51 can also protect the heat pump system from damage that may be caused by unstable water supply. For example, when the water source is suddenly interrupted, the water in the water storage device 51 can continue to supply the system for use, avoiding damage to the system due to water shortage. Among them, a water replenishment port can be set on the water storage device 51 of the present invention to facilitate water replenishment.

[0043] As a possible embodiment, the heat pump system also includes a first water replenishment passage structure 60 and a heat source passage structure 61. The first water replenishment passage structure 60 and the evaporator 13 can exchange heat with the heat source passage structure 61. The water outlet of the first water replenishment passage structure 60 is connected to the inlet of the inlet passage structure 30. When a heat source is available, the heat source is introduced into the heat source passage structure 61. At this time, water can be replenished to the inlet passage structure 30 through the first water replenishment passage structure 60. Because the first water replenishment passage structure 60 and the evaporator 13 can exchange heat with the heat source passage structure 61, the system can use this heat source to preheat the incoming water and improve the heat exchange efficiency of the evaporator 13. This can also reduce the energy required for refrigerant evaporation in the evaporator 13, and the required evaporation temperature is relatively low, thereby reducing heat loss in the system. The higher inlet water temperature also helps to reach the flash evaporation temperature more quickly, thereby improving the flash evaporation efficiency.

[0044] The working process of the above-mentioned high-temperature steam scenario is introduced below.

[0045] When there is a heat source, the heat source will be introduced into the heat source passage structure 61. In this case, the water source is introduced into the first water supply passage structure 60. After the water absorbs heat from the heat source, it enters the first heat exchanger 40 and is heated by the transcritical refrigerant on the condensation side of the first refrigerant circuit 10 and the hot water in the return passage structure 31. Then it enters the second heat exchanger 41 and is heated by the mixed refrigerant on the condensation side of the second refrigerant circuit 20 and the hot water in the return passage structure 31. Then it enters the flash tank 50 and is flash evaporated into high-temperature steam. The high-temperature hot water after flash evaporation returns to the second heat exchanger 41 to heat the water in the inlet passage structure 30 and the low-pressure mixed refrigerant in the second refrigerant circuit 20. Then it enters the first heat exchanger 40 to heat the water in the hot inlet passage structure 30 and the mixed refrigerant on the evaporation side of the second refrigerant circuit 20, and then enters the water storage device 51 to realize water circulation.

[0046] In the first refrigerant circuit 10, the single-component transcritical refrigerant compressed by the first compressor 11 releases heat in the first heat exchanger 40, providing the required heat for the cold water in the inlet passage structure 30 and the low-pressure mixed refrigerant on the evaporation side of the second refrigerant circuit 20, and then flows to the evaporator 13 after being reduced in pressure and temperature by the first throttling device 12, and returns to the first compressor 11 after absorbing heat in the evaporator 13, thereby completing the transcritical cycle.

[0047] In the second refrigerant circuit 20, the mixed refrigerant compressed by the second compressor 21 condenses and releases heat in the second heat exchanger 41, providing the required heat for the temperature increase of the water in the inlet path structure 30 and the low-pressure heat recovery of the mixed refrigerant, and then flows into the second throttling device 22 to reduce the pressure and temperature. After flowing out of the second throttling device 22, it enters the first heat exchanger 40 to absorb the heat on the condensation side of the transcritical cycle and the waste heat in the return path structure 31, and then enters the second heat exchanger 41. After absorbing the heat released by the condensation of the mixed refrigerant and the heat of the high-temperature hot water in the return path structure 31 in the second heat exchanger 41, it returns to the second compressor 21, thereby completing the mixed refrigerant cycle.

[0048] The above-described configuration utilizes the transcritical constant-temperature phase-change heat transfer characteristics of the first refrigerant circuit 10 on the evaporation side, matching the same constant-temperature heat source (such as air, geothermal energy, etc.) on the evaporation side to reduce the heat exchange temperature difference between the transcritical evaporation side and the environment. The temperature glide characteristics of the transcritical condensation side are utilized to reduce the heat exchange temperature difference with the water in the inlet flow path structure 30, and the temperature glide characteristics of the mixed refrigerant on the evaporation side of the second refrigerant circuit 20 are matched to reduce the heat exchange temperature difference. On the condensation side of the second refrigerant circuit 20, the temperature glide characteristics of the condensation process are utilized to exchange heat with the water in the inlet flow path structure 30, reducing the heat exchange temperature difference, allowing the heat supply fluid to be heated to the required temperature, and matching the temperature glide characteristics of the mixed refrigerant on the heat recovery side of the second refrigerant circuit 20 to reduce heat loss. The evaporation side of the second refrigerant circuit 20 utilizes its temperature glide characteristics to match the temperature glide characteristics of the heat release side of the transcritical cycle to reduce the evaporation heat absorption heat exchange temperature difference, and uses the temperature glide characteristics to reduce the heat exchange temperature difference with the hot water in the return flow path structure 31. In this way, for the entire refrigeration system, whether it is the link of extracting heat from the environment, the link of supplying heat to the outside, or the link of heat exchange between refrigerants, small temperature difference heat exchange can be achieved, and the system efficiency is high.

[0049] As a possible embodiment, the heat pump system further includes a second water replenishment passageway structure 62, the outlet of which is connected to the inlet of the inlet passageway structure 30. This allows the system to use the second water replenishment passageway structure 62 to replenish water into the inlet passageway structure 30 when no heat source is available, thereby avoiding affecting the heat exchange efficiency of the evaporator 13 and ensuring normal system operation. The heat pump system of the present invention dynamically adjusts its operating path based on the availability of the external heat source, thereby maximizing energy efficiency under varying operating conditions.

[0050] The water outlet of the first water replenishment passage structure 60 of the present invention can be connected to the water replenishment port of the water storage device 51, thereby enabling communication between the first water replenishment passage structure 60 and the inlet of the inlet flow passage structure 30 through the water storage device 51. Alternatively, the first water replenishment passage structure 60 can be directly connected to the inlet of the inlet flow passage structure 30. The second water replenishment passage structure 62 of the present invention can be a water pipe, which can be connected to the water replenishment port of the water storage device 51, or directly connected to the inlet of the inlet flow passage structure 30, or the second water replenishment passage structure 62 can be configured as the water replenishment port of the water storage device 51, etc. These adjustments do not deviate from the principles of the present invention and are within the scope of protection of the present invention.

[0051] As a possible embodiment, the transcritical refrigerant of the present invention is one of CO2 (carbon dioxide), R290 (propane), R32 (difluoromethane), R410a, NH3 (ammonia), R152a (difluoroethane), R600a (isobutane), and R600 (n-butane), preferably CO2.

[0052] The mixed refrigerant is two or more of CO2 (carbon dioxide), R290 (propane), R32 (difluoromethane), R410a, NH3 (ammonia), R152a (difluoroethane), R600a (isobutane), R600 (n-butane), R601a, R601, cyclopentane, n-hexane, R134a (tetrafluoroethane), R1234yf, R1234ze, R245fa, R365mfc, R4310mee, R1224yd(Z), R1234ze(Z), R1233zd(E), R1336mzz(Z), and H2O (water). For high-temperature refrigerants, preferably, a refrigerant having a normal pressure boiling point higher than 50°C is used, such as n-hexane and water. For low-temperature working fluids, the selection is based on whether there is waste heat. When no heat source is available, working fluids with a normal pressure boiling point below -20°C are preferred, such as R290, R32, etc. When a heat source is available, the working fluid with a normal pressure boiling point between 30°C and -80°C can be selected based on the temperature of the heat source.

[0053] For hot water applications, the first heat exchanger 40 and the second heat exchanger 41 of the present invention implement three-stream heat exchange. The following describes possible implementations of the first heat exchanger 40 and the second heat exchanger 41. It should be noted that although the following description uses three embodiments, the specific configurations of the first heat exchanger 40 and the second heat exchanger 41 can be adjusted as long as heat exchange between the three streams can be achieved.

[0054] like Figure 3As shown, a first possible embodiment of a first heat exchanger 40 includes a first outer tube shell 401, a first tube bundle 402, and a second tube bundle 403. The first outer tube shell 401 is provided with a first tube shell inlet 4011 and a first tube shell outlet 4012. At least a portion of the first tube bundle 402 and at least a portion of the second tube bundle 403 are disposed within the first outer tube shell 401. One end of the first tube bundle 402 can be joined by a header to form a first tube bundle inlet 4021, and the other end can be joined by a header to form a first tube bundle outlet 4022. One end of the second tube bundle 403 can be joined by a header to form a second tube bundle inlet 4031, and the other end can be joined by a header to form a second tube bundle outlet 4032. Both ends of the first tube bundle 402 and the second tube bundle 403 can be sealed and extended beyond the first outer tube shell 401 to facilitate pipeline connection. The heat exchange tubes of the first tube bundle 402 and the second tube bundle 403 can be evenly distributed to achieve uniform heat exchange between the fluids.

[0055] In this case, the first tube shell inlet 4011 and the first tube shell outlet 4012 are connected to the refrigerant pipe section of the first refrigerant circuit 10 between the exhaust port of the first compressor 11 and the first throttling device 12, so that the high-temperature refrigerant compressed by the first compressor 11 enters the first outer tube shell 401 through the first tube shell inlet 4011 and then flows out to the first throttling device 12 through the first tube shell outlet 4012. The first tube bundle inlet 4021 and the first tube bundle outlet 4022 are connected to the inlet passage structure 30, so that water can enter the first tube bundle 402 through the first tube bundle inlet 4021 and then flow out through the first tube bundle outlet 4022. The second tube bundle inlet 4031 and the second tube bundle outlet 4032 are connected to the refrigerant pipe section of the second refrigerant circuit 20 between the outlet of the second throttling device 22 and the second heat exchanger 41, so that the refrigerant throttled by the throttling device enters the second tube bundle 403 from the second tube bundle inlet 4031, and then flows to the second heat exchanger 41 from the second tube bundle outlet 4032.

[0056] The second heat exchanger 41 can have the same structure as the first possible embodiment of the first heat exchanger 40. In this case, the first shell and tube inlet 4011 and the first shell and tube outlet 4012 are connected to the refrigerant pipe section of the second refrigerant circuit 20 between the exhaust port of the second compressor 21 and the inlet of the second throttling device 22, so that the high-temperature refrigerant compressed by the second compressor 21 enters the first outer shell and tube 401 through the first shell and tube inlet 4011 and then flows out of the first shell and tube outlet 4012 to the second throttling device 22. The first tube bundle inlet 4021 and the first tube bundle outlet 4022 are connected to the inlet and flow passage structure 30, so that the water source, which has been preliminarily heated by the first heat exchanger 40, can enter the first tube bundle 402 through the first tube bundle inlet 4021 and then flow out of the first tube bundle outlet 4022. The second tube bundle inlet 4031 and the second tube bundle outlet 4032 are connected to the refrigerant pipe section of the second refrigerant circuit 20 between the first heat exchanger 40 and the suction port side of the second compressor 21, so that the refrigerant after heat exchange in the first heat exchanger 40 enters the second tube bundle 403 from the second tube bundle inlet 4031, and then flows to the second compressor 21 from the second tube bundle outlet 4032.

[0057] like Figure 4 As shown, a second possible embodiment of the first heat exchanger 40 includes a second outer shell 404, a first inner shell 405, and a third tube bundle 406. The third tube bundle 406 is at least partially disposed within the first inner shell 405. The second outer shell 404 is sleeved outside the first inner shell 405, with a gap between the second outer shell 404 and the first inner shell 405 for fluid flow. One end of the third tube bundle 406 can be joined by a header to form a third tube bundle inlet 4061, and the other end can be joined by a header to form a third tube bundle outlet 4062. Both ends of the third tube bundle 406 can be sealed and extended beyond the first inner shell 405 to facilitate pipeline connection. Opposite sides of the first inner shell 405 can be extended beyond the second outer shell 404. The portion of the first inner shell 405 extending beyond the second outer shell 404 is provided with a first inner shell inlet 4051 and a first inner shell outlet 4052. The second outer tube shell 404 is provided with a second tube shell inlet 4041 and a second tube shell outlet 4042 .

[0058] In this case, the first inner shell inlet 4051 and the first inner shell outlet 4052 can be connected to the refrigerant pipe section of the first refrigerant circuit 10 between the exhaust port of the first compressor 11 and the first throttling device 12, so that the high-temperature refrigerant compressed by the first compressor 11 enters the first inner shell 405 through the first inner shell inlet 4051 and then flows out to the first throttling device 12 through the first inner shell outlet 4052. The second shell inlet 4041 and the second shell outlet 4042 are connected to the inlet passage structure 30, so that water can enter the flow gap between the second outer shell 404 and the first inner shell 405 through the second shell inlet 4041 and then flow out through the second shell outlet 4042. The third tube bundle inlet 4061 and the third tube bundle outlet 4062 are connected to the refrigerant pipe section of the second refrigerant circuit 20 between the outlet of the second throttling device 22 and the second heat exchanger 41, so that the refrigerant throttled by the throttling device enters the third tube bundle 406 through the third tube bundle inlet 4061 and then flows to the second heat exchanger 41 through the third tube bundle outlet 4062. Alternatively, the second shell and tube inlet 4041 and the second shell and tube outlet 4042 can be connected to the refrigerant pipe section of the second refrigerant circuit 20 between the outlet of the second throttling device 22 and the second heat exchanger 41. The third tube bundle inlet 4061 and the third tube bundle outlet 4062 can be connected to the inlet passage structure 30.

[0059] The second heat exchanger 41 can have the same structure as the second possible embodiment of the first heat exchanger 40. In this case, the first inner shell inlet 4051 and the first inner shell outlet 4052 can be connected to the refrigerant pipe section of the second refrigerant circuit 20 between the exhaust port of the second compressor 21 and the inlet of the second throttling device 22, so that the high-temperature refrigerant compressed by the second compressor 21 enters the first inner shell 405 through the first inner shell inlet 4051 and then flows out of the first inner shell outlet 4052 to the second throttling device 22. The second shell inlet 4041 and the second shell outlet 4042 are connected to the inlet passage structure 30, so that the water source, which has been preliminarily heated by the first heat exchanger 40, can enter the flow gap between the second outer shell 404 and the first inner shell 405 through the second shell inlet 4041 and then flow out of the second shell outlet 4042. The third tube bundle inlet 4061 and the third tube bundle outlet 4062 are connected to the refrigerant pipe section of the second refrigerant circuit 20 between the first heat exchanger 40 and the suction port side of the second compressor 21, so that the refrigerant after heat exchange in the first heat exchanger 40 enters the third tube bundle 406 through the third tube bundle inlet 4061 and then flows to the second compressor 21 through the third tube bundle outlet 4062. Alternatively, the second tube shell inlet 4041 and the second tube shell outlet 4042 can be connected to the refrigerant pipe section of the second refrigerant circuit 20 between the first heat exchanger 40 and the suction port side of the second compressor 21. The third tube bundle inlet 4061 and the third tube bundle outlet 4062 can be connected to the inlet passage structure 30.

[0060] like Figure 5 As shown, a third possible embodiment of the first heat exchanger 40 is a plate heat exchanger comprising a plurality of stacked first sections, the first section comprising a first cold plate (h), a hot plate (i), a second cold plate (g), and a hot plate (i) stacked in sequence. The hot plate (i) of each first section contacts the first cold plate (h) of its adjacent first section, thereby forming a cyclic stacking structure of the first cold plate, hot plate, second cold plate, hot plate, first cold plate, hot plate, second cold plate, and hot plate, i.e., a higihigi stacking arrangement. The hot plates are connected in parallel to each other and form a heat flow inlet (i inlet) and a heat flow outlet (i outlet); the first cold plates are connected in parallel to each other and form a first cold inlet (h inlet) and a first cold outlet (h outlet); and the second cold plates are connected in parallel to each other and form a second cold inlet (g inlet) and a second cold outlet (g outlet). The stacked structure of this plate heat exchanger (alternating hot and cold plates) provides a large surface area, allowing heat to be transferred more efficiently from the refrigerant to the water within a smaller volume, thereby improving heat transfer efficiency. Furthermore, fins can be added to the plate heat exchanger to enhance heat transfer.

[0061] In this case, the hot flow inlet and the hot flow outlet are connected to the refrigerant pipe section of the first refrigerant circuit 10 between the exhaust port of the first compressor 11 and the first throttling device 12, so that the high-temperature refrigerant compressed by the first compressor 11 enters the hot layer plate from the hot flow inlet, and then flows out from the hot flow outlet to the first throttling device 12. The first cold inlet and the first cold outlet are connected to the inlet passage structure 30, so that the water source can enter the first cold layer plate from the first cold inlet, and then flow out from the first cold outlet. The second cold inlet and the second cold outlet are connected to the refrigerant pipe section of the second refrigerant circuit 20 between the outlet of the second throttling device 22 and the second heat exchanger 41, so that the refrigerant throttled by the throttling device enters the second cold layer plate from the second cold inlet, and then flows to the second heat exchanger 41 from the second cold outlet. Alternatively, the second cold inlet and the second cold outlet are connected to the inlet passage structure 30 , and the first cold inlet and the first cold outlet are connected to the refrigerant pipe section of the second refrigerant circuit 20 between the outlet of the second throttling device 22 and the second heat exchanger 41 .

[0062] The second heat exchanger 41 can have the same structure as the third possible embodiment of the first heat exchanger 40. In this case, the hot flow inlet and hot flow outlet are connected to the refrigerant pipe section of the second refrigerant circuit 20 between the exhaust port of the second compressor 21 and the inlet of the second throttling device 22, allowing the high-temperature refrigerant compressed by the second compressor 21 to enter the hot layer plate through the hot flow inlet and then flow out of the hot flow outlet to the second throttling device 22. The first cold inlet and first cold outlet are connected to the inlet passage structure 30, allowing the water source, preliminarily heated by the first heat exchanger 40, to enter the first cold layer plate through the first cold inlet and then flow out of the first cold outlet. The second cold inlet and second cold outlet are connected to the refrigerant pipe section of the second refrigerant circuit 20 between the first heat exchanger 40 and the intake port of the second compressor 21, allowing the refrigerant, after heat exchange in the first heat exchanger 40, to enter the second cold layer plate through the second cold inlet and then flow out of the second cold outlet to the second compressor 21. Alternatively, the second cold inlet and the second cold outlet are connected to the inlet passage structure 30 , and the first cold inlet and the first cold outlet are connected to the refrigerant pipe section of the second refrigerant circuit 20 between the first heat exchanger 40 and the suction port side of the second compressor 21 .

[0063] For high-temperature steam scenarios, the first heat exchanger 40 and the second heat exchanger 41 of the present invention employ four-stream heat exchange. The following describes possible implementations of the first heat exchanger 40 and the second heat exchanger 41. It should be noted that although two embodiments are described below, the specific configurations of the first heat exchanger 40 and the second heat exchanger 41 can be adjusted as long as heat exchange between the four streams can be achieved.

[0064] like Figure 6 As shown, a first possible embodiment of the first heat exchanger 40 includes a third outer tube shell 407, a fourth tube bundle 408, and a double-tube structure. The fourth tube bundle 408 and the double-tube structure are at least partially disposed within the third outer tube shell 407. The double-tube structure includes a fifth tube bundle 409 and a second inner tube shell 410. The fifth tube bundle 409 is at least partially disposed within the second inner tube shell 410. One end of the fourth tube bundle 408 can be joined by a header to form a fourth tube bundle inlet 4081, and the other end can also be joined by a header to form a fourth tube bundle outlet 4082. Both ends of the fourth tube bundle 408 are sealed and extend beyond the third outer tube shell 407. One end of the fifth tube bundle 409 can be joined by a header to form a fifth tube bundle inlet 4091, and the other end can also be joined by a header to form a fifth tube bundle outlet 4092. Both ends of the fifth tube bundle 409 are sealed and extend beyond the second inner tube shell 410. The second inner shell 410 can pass through the third outer shell 407 in a sealed manner. The portion of the second inner shell 410 passing through the third outer shell 407 is provided with a second inner shell inlet 4101 and a second inner shell outlet 4102. The third outer shell 407 is provided with a third shell inlet 4071 and a third shell outlet 4072.

[0065] In this case, either the high-temperature refrigerant compressed by the first compressor 11 or the hot water flowing out of the hot water outlet of the flash tank 50 can flow into the third outer tube shell 407, and another hot fluid can flow into the fifth tube bundle 409. Either the water in the inlet flow path structure 30 or the refrigerant throttled and depressurized by the second throttling device 22 can flow into the fourth tube bundle 408, and another cold fluid can flow into the second inner tube shell 410. Alternatively, either the water in the inlet flow path structure 30 or the refrigerant throttled and depressurized by the second throttling device 22 can flow into the third outer tube shell 407, and another cold fluid can flow into the fifth tube bundle 409. Either the high-temperature refrigerant compressed by the first compressor 11 or the hot water flowing out of the hot water outlet of the flash tank 50 can flow into the fourth tube bundle 408, and another hot fluid can flow into the second inner tube shell 410.

[0066] The second heat exchanger 41 can have the same structure as the first possible embodiment of the first heat exchanger 40 in the steam scenario. In this case, the third outer tube shell 407 can flow with either the high-temperature refrigerant compressed by the second compressor 21 or the hot water flowing out of the hot water outlet of the flash tank 50, and the fifth tube bundle 409 can flow with another hot fluid. The fourth tube bundle 408 can flow with either the water in the inlet flow path structure 30 or the refrigerant after heat exchange in the first heat exchanger 40, and the second inner tube shell 410 can flow with another cold fluid. Alternatively, the third outer tube shell 407 can flow with either the water in the inlet flow path structure 30 or the refrigerant after heat exchange in the first heat exchanger 40, and the fifth tube bundle 409 can flow with another cold fluid. The fourth tube bundle 408 can flow with either the high-temperature refrigerant compressed by the second compressor 21 or the hot water flowing out of the hot water outlet of the flash tank 50, and the second inner tube shell 410 can flow with another hot fluid.

[0067] like Figure 7As shown, a second possible embodiment of the first heat exchanger 40 is that the first heat exchanger 40 constitutes a plate heat exchanger, which includes a plurality of stacked second sections, the second sections including a first hot plate (d), a first cold plate (e), a second hot plate (f), and a second cold plate (g) stacked in sequence, with the second cold plate (g) of at least one second section adjacent to the first hot plate (d) of its adjacent second section. Furthermore, the second cold plate of each second section is adjacent to the first hot plate of its adjacent second section; thereby forming a cyclic stacking structure of the first hot plate, the first cold plate, the second hot plate, the second cold plate, the first hot plate, the first cold plate, the second hot plate, and the second cold plate, i.e., a cyclic stacking structure of defgdefg. Each first cold plate is connected in parallel to each other and forms a first cold plate inlet and a first cold plate outlet; each second cold plate is connected in parallel to each other and forms a second cold plate inlet and a second cold plate outlet; each first hot plate is connected in parallel to each other and forms a first hot plate inlet and a first hot plate outlet; each second hot plate is connected in parallel to each other and forms a second hot plate inlet and a second hot plate outlet. Furthermore, fins may be added to the plate heat exchanger to enhance heat exchange.

[0068] In this case, the first cold plate can be fed with either the water in the inlet passage structure 30 or the refrigerant throttled and depressurized by the second throttling device 22, while the second cold plate can be fed with the other cold fluid. The first hot plate can be fed with either the high-temperature refrigerant compressed by the first compressor 11 or the hot water flowing out of the hot water outlet of the flash tank 50, while the second hot plate can be fed with the other hot fluid.

[0069] The second heat exchanger 41 can have the same structure as the second possible embodiment of the first heat exchanger 40 in the steam scenario. In this case, the first cold plate can flow with either the water in the inlet and outlet passages 30 or the refrigerant after heat exchange in the first heat exchanger 40, while the second cold plate can flow with the other cold fluid. The first hot plate can flow with either the high-temperature refrigerant compressed by the second compressor 21 or the hot water flowing from the hot water outlet of the flash tank 50, while the second hot plate can flow with the other hot fluid.

[0070] As a possible implementation method, refer to Figure 2The heat source passage structure 61 includes a heat exchange cavity 611, and a heat source inlet and a heat source outlet are provided on the heat exchange cavity 611. The evaporator 13 and the first water supply passage structure 60 are provided in the heat exchange cavity 611. If the heat exchange cavity 611 is also provided with a first interface, a second interface, a third interface and a fourth interface, the two ends of the evaporator 13 are respectively connected to the first interface and the second interface, and the two ends of the first water supply passage structure 60 are respectively connected to the third interface and the fourth interface, the first interface and the second interface are also connected to the first refrigerant circuit 10, and the fourth interface is connected to the water inlet end of the inlet passage structure 30. Of course, the above is not restrictive, and its setting method can be adjusted. For example, both ends of the evaporator 13 and the first water supply passage structure 60 extend from the heat source inlet and the heat source outlet to achieve connection with the first refrigerant circuit 10 and the water inlet end of the inlet passage structure 30, etc. These adjustments do not deviate from the principles of the present invention and are within the scope of protection of the present invention.

[0071] Since the evaporator 13 and the first water supply passage structure 60 are located in the same heat exchange cavity 611, a more direct heat exchange process can be achieved, heat loss can be reduced, and thus the efficiency of heat exchange can be improved. As an integrated unit, the heat exchange cavity 611 facilitates the management and optimization of heat flow and distribution, and the thermal efficiency and system response speed can be further improved through design optimization. Because the heat exchange between the evaporator 13 and the first water supply passage structure 60 is carried out in the same closed environment, flow regulating valves can be set at the heat source inlet and the heat source outlet respectively to accurately control the heat source heat entering the heat exchange cavity 611, ensuring that the temperature in the heat exchange cavity 611 meets the requirements and is neither too high nor too low. In addition, the design provided in the heat exchange cavity 611 allows the evaporator 13 and the first water supply passage structure 60 to adapt to different heat source changes, because the internal components can be more easily reconfigured or adjusted as needed to best utilize the different heat source characteristics.

[0072] As another possible embodiment, the heat source passage structure 61 is arranged outside the first water replenishment passage structure 60, and the evaporator 13 is arranged outside the heat source passage structure 61. Or the heat source passage structure 61 is arranged outside the evaporator 13, and the first water replenishment passage structure 60 is arranged outside the heat source passage structure 61. As a result, the first water replenishment passage structure 60, the heat source passage structure 61 and the evaporator 13 form a composite concentric tube heat exchange structure. The concentric tube design allows heat to be efficiently transferred between fluids because the contact area between the heat source passage structure 61 and the first water replenishment passage structure 60 and the evaporator 13 passage is large, which helps to improve the efficiency of energy transfer. In addition, the loss of heat energy during the transfer process can be minimized, especially the radiation and convection losses during the transfer process.

[0073] It can be understood that the heat exchanger structure composed of the above-mentioned heat source passage structure 61, the first water replenishment passage structure 60 and the evaporator 13 is not restrictive. As long as the heat exchange between them can be achieved, its specific form can be adjusted. For example, a plate heat exchanger can be formed, etc. These adjustments do not deviate from the principles of the present invention and are within the scope of protection of the present invention.

[0074] 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.

[0075] For example, as an alternative embodiment, although the present invention is introduced with the first heat exchanger 40 and the second heat exchanger 41 both being arranged on the reflux passage structure 31, the arrangement method is not unique. For example, only the first heat exchanger 40 or the second heat exchanger 41 can be arranged on the reflux passage structure 31. These adjustments do not deviate from the principles of the present invention and are within the scope of protection of the present invention.

[0076] 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 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 heat exchanger, a second throttling device and the first heat exchanger are sequentially provided on the second refrigerant circuit; an inlet flow passage structure, wherein the second heat exchanger is further provided on the inlet flow passage structure; The refrigerant in the first refrigerant circuit and the refrigerant in the second refrigerant circuit can exchange heat through the first heat exchanger; the refrigerant in the second refrigerant circuit and the fluid in the inlet flow path structure can exchange heat through the second heat exchanger; The refrigerant in the first refrigerant circuit is a transcritical refrigerant, and the refrigerant in the second refrigerant circuit is a mixed refrigerant.

2. The heat pump system according to claim 1, characterized in that The first heat exchanger is also provided on the inlet passage structure so that the fluid in the inlet passage structure can undergo heat exchange through the first heat exchanger. The first heat exchanger and the second heat exchanger are sequentially arranged in the direction from the inlet to the outlet of the inlet passage structure.

3. The heat pump system according to claim 1 or 2, characterized in that: The second heat exchanger is further provided on the refrigerant pipe section between the first heat exchanger and the suction port side of the second compressor, so that the refrigerant in the refrigerant pipe section can exchange heat through the second heat exchanger.

4. The heat pump system according to claim 3, characterized in that The heat pump system further comprises a flash tank and a reflux passage structure, wherein the outlet of the inlet passage structure is communicated with the water inlet of the flash tank, and the hot water outlet of the flash tank is communicated with the reflux passage structure; The first heat exchanger is also provided on the reflux passage structure so that the fluid in the reflux passage structure can exchange heat through the first heat exchanger, and / or the second heat exchanger is also provided on the reflux passage structure so that the fluid in the reflux passage structure can exchange heat through the second heat exchanger.

5. The heat pump system according to claim 4, characterized in that The heat pump system further includes a water storage device, which includes a water inlet and a water outlet. The water outlet end of the reflux passage structure is communicated with the water inlet, and the water outlet is communicated with the inlet of the inlet passage structure.

6. The heat pump system according to claim 1, characterized in that The heat pump system also includes a first water replenishment passage structure and a heat source passage structure. The first water replenishment passage structure can exchange heat with the heat source passage structure. The water outlet end of the first water replenishment passage structure is connected to the inlet of the inlet passage structure.

7. The heat pump system according to claim 6, characterized in that The heat source passage structure is capable of exchanging heat with the evaporator.

8. The heat pump system according to claim 7, characterized in that The heat pump system further includes a second water replenishment passage structure, wherein a water outlet end of the second water replenishment passage structure is in communication with an inlet of the inlet passage structure.

9. The heat pump system according to claim 5, characterized in that The heat pump system further includes a water pump, which is arranged on the inlet passage structure or the return passage structure.

10. The heat pump system according to claim 5, characterized in that A pressure reducing device is provided on the inlet passage structure on one side of the water inlet of the flash tank.

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