Cascade heat pump system

Abstract

The utility model provides a cascade heat pump system which comprises a first heat exchanger and a temperature adjusting system, the first heat exchanger is provided with a first heat exchange channel and a second heat exchange channel, and the first heat exchange channel is used for being communicated with a water path; a first medium pipeline and a second medium pipeline are arranged in the temperature adjusting system in parallel, the first medium pipeline communicates with the second heat exchange channel, and a first throttling device is installed on the first medium pipeline. The second medium pipeline is connected with the second heat exchange channel in parallel, and a second throttling device is installed on the second medium pipeline. In the defrosting mode, the scheme can absorb corresponding heat from the water path as required, and has an energy unloading effect. The system can absorb reasonable heat in the running state of different water temperatures, it is ensured that the system is safe and stable during defrosting, and the system has the advantage of saving energy.

Description

Technical Field

[0001] The utility model relates to the technical field of temperature control, in particular to a cascade heat pump system. Background Art

[0002] As the country's environmental protection requirements increase, more and more projects are using air source heat pump cascade systems to produce high-temperature hot water or steam to replace boilers. In air source heat pump cascade systems, defrosting is also a concern. Existing defrosting solutions on the market have poor defrosting efficiency.

[0003] In the existing scheme, the cascade heat pump system includes two temperature control systems with heat exchange functions, namely the high-temperature temperature control system and the low-temperature temperature control system. Usually, in the defrosting mode, the high-temperature temperature control system does not participate in defrosting. The main disadvantage of this scheme is that there is an additional heat exchanger and the system cost is relatively high. Therefore, a scheme is needed in which the high-temperature temperature control system and the low-temperature temperature control system participate in defrosting at the same time.

[0004] Some technical solutions for defrosting heat pump systems are disclosed in the prior art, such as the patent application number 201610369016.9, which is titled "A two-stage compression switching to partial binary cascade air source heat pump defrosting system", including an indoor heat exchanger, an outdoor heat exchanger, a gas-liquid separator, a compressor, a high-pressure liquid reservoir, a four-way reversing valve, an economizer, a stop valve, a defrosting branch and a supplementary heat branch; the two ends of the first defrosting branch are respectively connected to the inlet of the outdoor heat exchanger and the gas-liquid separator; the two ends of the second defrosting branch are respectively connected to the exhaust port of the low-pressure compressor and the inlet of the economizer cooling coil; one end of the supplementary heat branch is connected to the four-way reversing valve, and the other end is directly connected to the liquid phase of the high-pressure liquid reservoir, a supplementary heat solenoid valve is installed on the branch, and a supplementary heat sensor is placed in the liquid phase of the high-pressure liquid reservoir. Although this solution can achieve the purpose of defrosting, the defrosting efficiency is low, which is not conducive to the specific use of this solution.

[0005] For example, the application number is 202223355000.2, and the patent name is a cascade heat pump system with heating, cooling and defrosting functions, including a first heat exchanger, a second heat exchanger, a first heat exchange system, a second heat exchange system, and a third heat exchange system; the first heat exchange system and the second heat exchange system perform heat exchange at the first heat exchanger, one refrigerant circuit of the second heat exchanger is in the first heat exchange system, and the other refrigerant circuit is in the third heat exchange system, and the third heat exchange system exchanges heat with the outside at the second heat exchanger; the third heat exchange system includes some components in the second heat exchange system, and the third heat exchange system and the second heat exchange system share the same heat exchange medium, and the third heat exchange system and the second heat exchange system do not work at the same time; although this scheme can achieve the purpose of defrosting, the high-temperature temperature control system in the scheme lacks energy unloading. When the high-temperature temperature control system absorbs too much heat from the environment, and the low-temperature temperature control system cannot transport the heat in time, it causes waste and affects the ambient temperature.

[0006] In addition, there are some solutions about heat pumps in the prior art, such as heat exchange between the low-temperature temperature control system and the high-temperature temperature control system, and the high-temperature temperature control system heats the water circuit. In this solution, when defrosting, the high-temperature temperature control system directly absorbs heat from the water circuit and reversely transfers the heat to the low-temperature temperature control system, and the low-temperature temperature control system is used for defrosting. However, when the return water temperature in the water circuit is too high, the water circuit directly exchanges heat with the high-temperature temperature control system, which is likely to cause a high-pressure alarm in the high-temperature temperature control system, making the specific use of this solution a safety hazard.

[0007] Therefore, the technical problem to be solved in this application is: how to defrost the heat pump system in a more energy-saving and safer way. Utility Model Content

[0008] In order to solve the above technical problems, the utility model proposes a cascade heat pump system. In the defrost mode, the solution can more reasonably absorb the corresponding heat from the water circuit, has the effect of energy unloading, can avoid the system high pressure alarm caused by the excessive return water temperature, has the advantages of safety and reliability, and ensures that the defrosting of the system can be completed safely and efficiently under different water temperatures. The solution sets a first throttling device and a second throttling device in parallel. By adjusting the opening of the two, it is used to enable the temperature control system to absorb appropriate heat from the water circuit, improve the utilization rate of heat, and have the advantages of energy saving while ensuring the safety of the system.

[0009] Specifically, the utility model proposes a cascade heat pump system, including a first heat exchanger and a temperature adjustment system, the first heat exchanger having a first heat exchange channel and a second heat exchange channel, the first heat exchange channel being used to connect a water circuit;

[0010] The temperature control system includes a first medium pipeline and a second medium pipeline connected in parallel, the first medium pipeline is connected to the second heat exchange channel, and a first throttling device is installed on the first medium pipeline; the second medium pipeline is connected to the second heat exchange channel in parallel, and a second throttling device is installed on the second medium pipeline.

[0011] Preferably, the temperature adjustment system includes a first temperature control module and a second temperature control module, the first temperature control module includes the first medium pipeline and the second medium pipeline, and the second temperature control module performs heat exchange with the first temperature control module through a second heat exchanger.

[0012] Preferably, the second heat exchanger has a third heat exchange channel and a fourth heat exchange channel, the third heat exchange channel is arranged in the first temperature control module, and the fourth heat exchange channel is arranged in the second temperature control module.

[0013] Preferably, the first temperature control module comprises:

[0014] A first four-way valve, wherein the first four-way valve has a first interface, a second interface, a third interface and a fourth interface;

[0015] A first compressor, wherein the exhaust port of the first compressor is connected to the first interface via a third medium pipeline; the second interface is connected to the first medium pipeline and the second medium pipeline respectively;

[0016] A first liquid storage tank, one side of which is connected to the first medium pipeline and the second medium pipeline respectively, and the first medium pipeline is located between the first four-way valve and the first liquid storage tank; the other side of the first liquid storage tank is connected to the fourth interface through a third heat exchange channel;

[0017] The third interface is used to deliver the medium to the air inlet of the first compressor.

[0018] Preferably, the first temperature control module also includes a first gas-liquid separator, an input end of the first gas-liquid separator is connected to the third interface through a fourth medium pipeline, and an output end of the first gas-liquid separator is connected to the air inlet of the first compressor through a fifth medium pipeline.

[0019] Preferably, a one-way valve is installed on the second medium pipeline.

[0020] Preferably, the second temperature control module includes:

[0021] A second four-way valve, wherein the second four-way valve has a fifth interface, a sixth interface, a seventh interface and an eighth interface;

[0022] a second compressor, the exhaust port of the second compressor being connected to the fifth interface via a sixth medium pipeline;

[0023] A second liquid storage tank, one side of the second liquid storage tank is connected to the sixth interface through a fourth heat exchange channel, and the other side of the second liquid storage tank is connected to the eighth interface through a third heat exchanger;

[0024] The seventh interface is used for conveying medium to the air inlet of the second compressor.

[0025] Preferably, the second liquid storage tank and the third heat exchanger are connected via a third throttling device.

[0026] Preferably, the second temperature control module also includes a second gas-liquid separator, the input end of the second gas-liquid separator is connected to the seventh interface through a seventh medium pipeline, and the output end of the second gas-liquid separator is connected to the air inlet of the second compressor through an eighth medium pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the drawings required to be used in the embodiments or the description of the prior art will be briefly introduced below.

[0028] Figure 1 is a structural schematic diagram of the cascade heat pump system proposed in this embodiment;

[0029] Figure 2 is a schematic diagram of the medium flow direction of the cascade heat pump system of this embodiment in the heating mode;

[0030] Figure 3 Schematic diagram of the medium flow direction of the cascade heat pump system in the defrost mode of this embodiment

[0031] Figure 4 It is a schematic diagram of the adjustment method of the first throttling device, the second throttling device and the third throttling device of the cascade heat pump system in the defrost mode in this embodiment.

[0032] The reference numerals in the accompanying drawings are as follows:

[0033] 11-first heat exchanger; 12-first heat exchange channel; 13-second heat exchange channel; 14-water channel; 15-first medium pipeline; 16-second medium pipeline; 17-first throttling device; 18-second throttling device; 19-first temperature control module; 20-second temperature control module; 21-second heat exchanger; 22-third heat exchange channel; 23-fourth heat exchange channel; 24-No. 1 interface; 25-No. 2 interface; 26-No. 3 interface; 27-No. 4 interface; 28-first compressor; 29-third medium pipeline; 30-first liquid storage tank; 31-first gas-liquid separator; 32-fourth medium pipeline; 33- The fifth medium pipeline; 34-one-way valve; 35-interface No. 5; 36-interface No. 6; 37-interface No. 7; 38-interface No. 8; 39-second compressor; 40-sixth medium pipeline; 41-second liquid storage tank; 42-third heat exchanger; 43-second gas-liquid separator; 44-seventh medium pipeline; 45-eighth medium pipeline; 46-third throttling device; 47-first pressure sensor; 48-first temperature sensor; 49-second pressure sensor; 50-second temperature sensor; 51-third pressure sensor; 52-third temperature sensor; 53-fourth pressure sensor; 54-fourth temperature sensor. DETAILED DESCRIPTION

[0034] The technical solution of the present application is further described below in conjunction with specific embodiments, but the present application is not limited to these embodiments.

[0035] like Figure 1 As shown, this embodiment proposes a cascade heat pump system, including a first heat exchanger 11 and a temperature adjustment system, the first heat exchanger 11, the first heat exchanger 11 has a first heat exchange channel 12 and a second heat exchange channel 13, the first heat exchange channel 12 is used to connect to a water channel 14;

[0036] A first medium pipeline 15 and a second medium pipeline 16 are provided in parallel in the temperature control system. The first medium pipeline 15 is connected to the second heat exchange channel 13, and a first throttling device 17 is installed on the first medium pipeline 15; the second medium pipeline 16 is connected in parallel to the second heat exchange channel 13, and a second throttling device 18 is installed on the second medium pipeline 16.

[0037] In the defrosting mode, this solution proposes an energy unloading solution, which can more reasonably absorb the corresponding heat from the water channel 14, effectively avoid the high pressure alarm of the system, and ensure the safety and reliability of the system defrosting operation. It also has the advantage of energy saving.

[0038] In this solution, the first throttling device 17 and the second throttling device 18 are arranged in parallel, and by adjusting the opening of the first throttling device 17 and the second throttling device 18, the temperature regulating system can absorb appropriate heat from the water circuit 14, thereby ensuring the safe and reliable defrosting operation of the system.

[0039] As an implementation mode of this embodiment, the temperature regulation system includes a first temperature control module 19 and a second temperature control module 20, the first temperature control module 19 includes the first medium pipeline 15 and the second medium pipeline 16, and the second temperature control module 20 performs heat exchange with the first temperature control module 19 through a second heat exchanger 21.

[0040] The first temperature control module 19 and the second temperature control module 20 in this solution exchange heat with each other to ensure the working efficiency in the heating or defrosting mode.

[0041] Furthermore, the second heat exchanger 21 has a third heat exchange channel 22 and a fourth heat exchange channel 23 . The third heat exchange channel 22 is provided in the first temperature control module 19 , and the fourth heat exchange channel 23 is provided in the second temperature control module 20 .

[0042] Furthermore, an intermediate temperature sensor is provided on the second heat exchanger 21 .

[0043] As an implementation of this embodiment, the first temperature control module 19 includes:

[0044] A first four-way valve, wherein the first four-way valve has a first interface 24, a second interface 25, a third interface 26 and a fourth interface 27;

[0045] A first compressor 28, the exhaust port of the first compressor 28 is connected to the first interface 24 through a third medium pipeline 29; the second interface 25 is connected to the first medium pipeline 15 and the second medium pipeline 16 respectively;

[0046] A first liquid storage tank 30, one side of which is connected to the first medium pipeline 15 and the second medium pipeline 16 respectively, and the first medium pipeline 15 is located between the first four-way valve and the first liquid storage tank 30; the other side of the first liquid storage tank 30 is connected to the fourth interface 27 through the third heat exchange channel 22;

[0047] The third interface 26 is used to deliver the medium to the air inlet of the first compressor 28 .

[0048] The present solution discloses the specific composition of the first temperature control module 19, wherein the first compressor 28 is a high-temperature fixed-frequency compressor.

[0049] Furthermore, the first temperature control module 19 also includes a first gas-liquid separator 31, the input end of the first gas-liquid separator 31 is connected to the third interface 26 through a fourth medium pipeline 32, and the output end of the first gas-liquid separator 31 is connected to the air inlet of the first compressor 28 through a fifth medium pipeline 33.

[0050] As an implementation of this embodiment, a one-way valve 34 is installed on the second medium pipeline 16 , wherein the flow direction of the one-way valve 34 is: from the first liquid storage tank 30 to the second interface 25 .

[0051] Furthermore, the third medium pipeline 29 is provided with a first pressure sensor 47 and a first temperature sensor 48 ; the fifth medium pipeline 33 is provided with a second pressure sensor 49 and a second temperature sensor 50 .

[0052] As an implementation of this embodiment, the second temperature control module 20 includes:

[0053] A second four-way valve, wherein the second four-way valve has a fifth interface 35, a sixth interface 36, a seventh interface 37 and an eighth interface 38;

[0054] A second compressor 39, the exhaust port of the second compressor 39 is connected to the fifth interface 35 through a sixth medium pipeline 40;

[0055] A second liquid storage tank 41, one side of the second liquid storage tank 41 is connected to the sixth interface 36 through the fourth heat exchange channel 23, and the other side of the second liquid storage tank 41 is connected to the eighth interface 38 through the third heat exchanger 42;

[0056] The seventh interface 37 is used for conveying medium through the air inlet of the second compressor 39 .

[0057] Furthermore, the second temperature control module 20 also includes a second gas-liquid separator 43, the input end of the second gas-liquid separator 43 is connected to the seventh interface 37 through the seventh medium pipeline 44, and the output end of the second gas-liquid separator 43 is connected to the air inlet of the second compressor 39 through the eighth medium pipeline 45.

[0058] Furthermore, the second liquid storage tank 41 and the third heat exchanger 42 are connected via a third throttling device 46 .

[0059] The sixth medium pipeline 40 is provided with a third pressure sensor 51 and a third temperature sensor 52 ; the eighth medium pipeline 45 is provided with a fourth pressure sensor 53 and a fourth temperature sensor 54 .

[0060] Furthermore, the third heat exchanger 42 is an air-side heat exchanger and adopts a fin heat exchanger structure.

[0061] like Figure 2 As shown, the working process of this scheme in heating mode is as follows:

[0062] The medium discharged from the first compressor 28 flows into the second heat exchange channel 13 through the third medium pipeline 29, the first interface 24 and the second interface 25. At the same time, the water in the water channel 14 passes through the first heat exchange channel 12 and exchanges heat with the medium to heat the water.

[0063] Then the medium in the second heat exchange channel 13 flows into the first liquid storage tank 30, and the medium in the first liquid storage tank 30 flows into the first gas-liquid separator 31 through the third heat exchange channel 22, the fourth interface 27, and the third interface 26. After the gas-liquid separation, the gaseous medium flows into the air inlet of the first compressor 28 through the fifth medium pipeline 33.

[0064] At the same time, the second temperature control module 20 supplies heat to the first temperature control module 19, wherein the medium discharged from the second compressor 39 flows into the fourth heat exchange channel 23 through the sixth medium pipeline 40, the fifth interface 35, and the sixth interface 36, and is used to heat the medium in the third heat exchange channel 22.

[0065] Then, the fourth heat exchange channel 23 flows into the third heat exchanger 42 through the second liquid storage tank 41 and the third throttling device 46. At this time, the third heat exchanger 42 absorbs heat from the air. The medium in the third heat exchanger 42 continues to flow into the second gas-liquid separator 43 through the eighth interface 38, the seventh interface 37, and the seventh medium pipeline 44. The filtered gaseous medium flows into the air inlet of the second compressor 39 through the eighth medium pipeline 45.

[0066] like Figure 3 As shown, the working process of this scheme in defrost mode is as follows:

[0067] The medium discharged from the first compressor 28 flows into the third heat exchange channel 22 through the third medium pipeline 29, the first interface 24 and the fourth interface 27, and is used to heat the second temperature control module 20. Then the medium in the third heat exchange channel 22 flows into the first medium pipeline 15 and the second medium pipeline 16 through the first liquid storage tank 30, respectively, and the heat exchange efficiency between the second heat exchange channel 13 and the water circuit is controlled by adjusting the opening of the first throttling device 17 and the second throttling device 18, so as to fully heat the medium. Then, after the medium in the first medium pipeline 15 and the second medium pipeline 16 is merged, it flows into the first gas-liquid separator 31 through the second interface 25, the third interface 26 and the fourth medium pipeline 32, and the gaseous medium after filtering flows into the air inlet of the first compressor 28 through the fifth medium pipeline 33.

[0068] At the same time, the medium discharged from the second compressor 39 flows into the third heat exchanger 42 through the sixth medium pipeline 40, the fifth interface 35, and the eighth interface 38, thereby realizing the defrosting of the third heat exchanger 42. The medium in the third heat exchanger 42 flows into the fourth heat exchange channel 23 through the third throttling device 46 and the second liquid storage tank 41, and is used to absorb the heat in the third heat exchange channel 22. Then, the medium of the fourth heat exchange channel 23 flows into the second gas-liquid separator 43 through the sixth interface 36, the seventh interface 37 and the seventh medium pipeline 44. The separated gaseous medium flows into the air inlet of the second compressor 39 through the eighth medium pipeline 45.

[0069] The present invention also discloses a control method in the defrosting mode, which improves the defrosting efficiency by controlling the opening of the first throttling device 17, the second throttling device 18 and the third throttling device 46. The control method is as follows: Figure 4 In addition, the regulation method of the cascade heat pump system based on this scheme is not limited to Figure 4 A solution can also be used to adjust the adjustment method in specific usage scenarios.

[0070] For ordinary technicians in this field, several modifications and improvements can be made without departing from the creative concept of the utility model, which all fall within the protection scope of the utility model.

Claims

1. A cascade heat pump system, characterized in that: The invention comprises a first heat exchanger (11) and a temperature adjustment system, wherein the first heat exchanger (11) has a first heat exchange channel (12) and a second heat exchange channel (13), and the first heat exchange channel (12) is used to connect to a water channel (14); The temperature control system is provided with a first medium pipeline (15) and a second medium pipeline (16) in parallel; the first medium pipeline (15) is connected to the second heat exchange channel (13), and a first throttling device (17) is installed on the first medium pipeline (15); the second medium pipeline (16) is connected to the second heat exchange channel (13) in parallel, and a second throttling device (18) is installed on the second medium pipeline (16).

2. The cascade heat pump system according to claim 1, characterized in that: The temperature adjustment system comprises a first temperature control module (19) and a second temperature control module (20), wherein the first temperature control module (19) comprises the first medium pipeline (15) and the second medium pipeline (16), and the second temperature control module (20) performs heat exchange with the first temperature control module (19) via a second heat exchanger (21).

3. The cascade heat pump system according to claim 2, characterized in that: The second heat exchanger (21) has a third heat exchange channel (22) and a fourth heat exchange channel (23); the third heat exchange channel (22) is arranged in the first temperature control module (19), and the fourth heat exchange channel (23) is arranged in the second temperature control module (20).

4. The cascade heat pump system according to claim 3, characterized in that: The first temperature control module (19) comprises: A first four-way valve, the first four-way valve having a first interface (24), a second interface (25), a third interface (26) and a fourth interface (27); A first compressor (28), wherein the exhaust port of the first compressor (28) is connected to the first interface (24) via a third medium pipeline (29); the second interface (25) is connected to the first medium pipeline (15) and the second medium pipeline (16) respectively; a first liquid storage tank (30), one side of the first liquid storage tank (30) being connected to the first medium pipeline (15) and the second medium pipeline (16) respectively, and the first medium pipeline (15) being located between the first four-way valve and the first liquid storage tank (30); the other side of the first liquid storage tank (30) being connected to the fourth interface (27) via a third heat exchange channel (22); The third interface (26) is used to deliver the medium to the air inlet of the first compressor (28).

5. The cascade heat pump system according to claim 4, characterized in that: The first temperature control module (19) further comprises a first gas-liquid separator (31), the input end of the first gas-liquid separator (31) being connected to the third interface (26) via a fourth medium pipeline (32), and the output end of the first gas-liquid separator (31) being connected to the air inlet of the first compressor (28) via a fifth medium pipeline (33).

6. The cascade heat pump system according to claim 5, characterized in that: A one-way valve (34) is installed on the second medium pipeline (16).

7. The cascade heat pump system according to claim 2, characterized in that: The second temperature control module (20) comprises: A second four-way valve, wherein the second four-way valve has a fifth interface (35), a sixth interface (36), a seventh interface (37) and an eighth interface (38); A second compressor (39), wherein an exhaust port of the second compressor (39) is connected to the fifth interface (35) via a sixth medium pipeline (40); A second liquid storage tank (41), one side of the second liquid storage tank (41) is connected to the sixth interface (36) through a fourth heat exchange channel (23), and the other side of the second liquid storage tank (41) is connected to the eighth interface (38) through a third heat exchanger (42); The seventh interface (37) is used to convey the medium through the air inlet of the second compressor (39).

8. The cascade heat pump system according to claim 7, characterized in that: The second temperature control module (20) further comprises a second gas-liquid separator (43), the input end of the second gas-liquid separator (43) being connected to the seventh interface (37) via a seventh medium pipeline (44), and the output end of the second gas-liquid separator (43) being connected to the air inlet of the second compressor (39) via an eighth medium pipeline (45).

9. The cascade heat pump system according to claim 7, characterized in that: The second liquid storage tank (41) and the third heat exchanger (42) are connected via a third throttling device (46).

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