CO2 heat pump system

Abstract

The invention relates to the technical field of air conditioners, in particular to a CO2 heat pump system. The CO2 heat pump system aims at solving the problem that an existing CO2 heat pump system is prone to scaling during heat supply. In order to achieve the purpose, the CO2 heat pump system comprises a compressor, a liquid storage tank, a throttling element and a first heat exchanger, the liquid storage tank is provided with a containing cavity, a refrigerant inlet and a refrigerant outlet are formed in the liquid storage tank, the refrigerant inlet communicates with the refrigerant outlet through the containing cavity, and an exhaust port of the compressor communicates with the refrigerant inlet; the refrigerant outlet communicates with a first port of the throttling element, a second port of the throttling element communicates with a first port of the first heat exchanger, and a second port of the first heat exchanger communicates with an air suction port of the compressor. Direct heat exchange between CO2 and liquid in the liquid storage tank can be achieved, scaling in the liquid storage tank is prevented through the reaction between CO2 and water scale, meanwhile, due to direct heat exchange between CO2 and liquid, the heat exchange effect is improved, arrangement of a heat exchanger in the liquid storage tank is omitted, and the equipment cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, and particularly to a CO2 heat pump system. Background Art

[0002] As a new type of environmentally friendly refrigerant, CO2 (carbon dioxide) has currently become a research hotspot in the heat pump industry. The advantages and disadvantages of a heat pump system using CO2 as a refrigerant are equally obvious. Its disadvantage is that the refrigeration efficiency is relatively poor, and its advantage is that the heating performance is generally better than that of traditional heat pumps. Therefore, currently, CO2 heat pump systems are usually used for heating or in the field of automotive air conditioners.

[0003] When a CO2 heat pump system is used for heating, higher water temperatures and lower energy consumption can be achieved. However, the applicant has found in actual application scenarios that the higher water temperature brings more serious scale problems, making it easier to scale inside the water tank, which has also become a major factor hindering the popularization of CO2 heat pump systems.

[0004] Correspondingly, a new technical solution is needed in this field to solve the above problems. Summary of the Invention

[0005] In order to solve at least one of the above problems in the prior art, that is, to solve the problem that the existing CO2 heat pump system is more likely to scale when heating, the present application provides a CO2 heat pump system. The CO2 heat pump system includes a compressor, a liquid storage tank, a throttling element, and a first heat exchanger. The liquid storage tank has an accommodation cavity. A refrigerant inlet and a refrigerant outlet are provided on the liquid storage tank. The refrigerant inlet and the refrigerant outlet are communicated through the accommodation cavity. The exhaust port of the compressor is communicated with the refrigerant inlet. The refrigerant outlet is communicated with the first port of the throttling element. The second port of the throttling element is communicated with the first port of the first heat exchanger. The second port of the first heat exchanger is communicated with the suction port of the compressor.

[0006] In the CO2 heat pump system of the present application, by providing a refrigerant inlet and a refrigerant outlet on the liquid storage tank, and respectively communicating the refrigerant inlet and the refrigerant outlet with the exhaust port of the compressor and the first port of the throttling element, when the CO2 heat pump system is operating, direct heat exchange between CO2 and the liquid in the liquid storage tank can be achieved, and the reaction between CO2 and scale is utilized to prevent scaling inside the liquid storage tank. At the same time, since CO2 directly exchanges heat with the liquid, it is beneficial to improve the heat exchange effect, save the setting of the heat exchanger inside the liquid storage tank, and reduce the equipment cost.

[0007] In a preferred technical solution of the above CO2 heat pump system, the refrigerant inlet is provided at the bottom of the liquid storage tank, and / or the refrigerant outlet is provided at the top of the liquid storage tank.

[0008] The above setting method is beneficial to improving the heat exchange effect between CO2 and the liquid.

[0009] In the preferred technical solution of the above CO2 heat pump system, the CO2 heat pump system further includes a gas distributor, and the gas distributor is arranged inside the liquid storage tank and communicated with the refrigerant inlet.

[0010] The above arrangement is beneficial to improving the dispersion effect of CO2 after entering the liquid storage tank and realizing uniform heat exchange between CO2 and the liquid.

[0011] In the preferred technical solution of the above CO2 heat pump system, the CO2 heat pump system further includes a flow equalizing plate, and the flow equalizing plate is arranged inside the liquid storage tank and above the gas distributor.

[0012] The above arrangement can further improve the dispersion effect of CO2 and realize uniform heat exchange between CO2 and the liquid.

[0013] In the preferred technical solution of the above CO2 heat pump system, the CO2 heat pump system further includes a second heat exchanger, the second heat exchanger has a cooling inlet, a cooling outlet, a heat exchange inlet and a heat exchange outlet, the heat exchange inlet is communicated with the refrigerant outlet, the cooling outlet is communicated with the first port of the throttling element, the heat exchange inlet is communicated with the second port of the first heat exchanger, and the heat exchange outlet is communicated with the suction port of the compressor.

[0014] The above arrangement can preliminarily cool the CO2 after heat exchange in the liquid storage tank, so that the water contained in the CO2 precipitates, and the system stability is improved.

[0015] In the preferred technical solution of the above CO2 heat pump system, the second heat exchanger further has a liquid discharge port, and a liquid discharge pipe is connected to the liquid discharge port.

[0016] The above arrangement can timely discharge the precipitated water.

[0017] In the preferred technical solution of the above CO2 heat pump system, the liquid storage tank has a liquid inlet and a liquid outlet, and the liquid discharge pipe is communicated with the liquid inlet.

[0018] The above arrangement can divert the precipitated water to the liquid storage tank and improve the recycling rate of water.

[0019] In the preferred technical solution of the above CO2 heat pump system, the CO2 heat pump system further includes a drying filter, the first port of the drying filter is communicated with the cooling outlet, and the second port of the drying filter is communicated with the first port of the throttling element.

[0020] The above arrangement can dry the CO2 by using the drying filter, avoid the occurrence of ice blockage phenomenon, and further improve the operation stability of the system.

[0021] In the preferred technical solution of the above CO2 heat pump system, the CO2 heat pump system further includes a bypass pipeline. The first end of the bypass pipeline is communicated with the exhaust port of the compressor, the second end of the bypass pipeline is communicated with the first port of the throttling element, and a first on-off valve is arranged on the pipeline between the first end of the bypass pipeline and the refrigerant inlet, and a second on-off valve is arranged on the bypass pipeline.

[0022] By setting the bypass pipeline, it is beneficial to defrost the first heat exchanger and at the same time avoid the accumulation of CO2 in the liquid storage tank and unable to circulate.

[0023] In the preferred technical solution of the above CO2 heat pump system, the bypass pipeline is arranged inside the liquid storage tank. Description of the Drawings

[0024] The CO2 heat pump system of the present application will be described below with reference to the drawings. In the drawings:

[0025] Figure 1 is the system diagram of the CO2 heat pump system of the present application.

[0026] List of Reference Numerals

[0027] 1. Compressor; 2. Liquid storage tank; 21. Refrigerant inlet; 22. Refrigerant outlet; 23. Liquid inlet; 24. Liquid outlet; 3. Throttling element; 4. First heat exchanger; 5. Four-way valve; 6. Gas distributor; 7. Second heat exchanger; 71. Cooling inlet; 72. Cooling outlet; 73. Heat exchange inlet; 74. Heat exchange outlet; 75. Drainage port; 8. Drying filter; 9. Bypass pipeline; 10. First on-off valve; 11. Second on-off valve; 12. Flow equalizing plate; 13. Liquid inlet pipe; 14. Liquid outlet pipe; 15. Drainage pipe. Detailed Embodiments

[0028] The preferred embodiments of the present application will be described below with reference to the drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principle of the present application and are not intended to limit the protection scope of the present application. For example, although the refrigerant inlet in the drawings is arranged at the bottom of the liquid storage tank, this positional relationship is not fixed, and those skilled in the art can adjust it according to needs to adapt to specific application scenarios. For example, the refrigerant inlet can also be arranged at the lower part of the side wall of the liquid outlet pipe, etc.

[0029] It should be noted that in the description of the present application, the terms indicating the direction or positional relationship, such as "upper", "lower", "left", "right", "inner", "outer", etc., are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or component must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present application. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. Additionally, in the description of the present application, "a plurality" means at least two.

[0030] Furthermore, it should be noted that in the description of the present application, unless otherwise clearly specified and defined, the terms "connected", "linked", "connected to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0031] First, refer to Figure 1 to describe the CO2 heat pump system of the present application. Among them, Figure 1 is the system diagram of the CO2 heat pump system of the present application.

[0032] As Figure 1 shown, in order to solve the problem that the existing CO2 heat pump system is more likely to scale during heating, the CO2 heat pump system of the present application includes a compressor 1, a liquid storage tank 2, a throttling element 3, and a first heat exchanger 4. The liquid storage tank 2 has a receiving cavity. A refrigerant inlet 21 and a refrigerant outlet 22 are provided on the liquid storage tank 2. The refrigerant inlet 21 and the refrigerant outlet 22 are communicated through the receiving cavity. The exhaust port of the compressor 1 is communicated with the refrigerant inlet 21. The refrigerant outlet 22 is communicated with the first port of the throttling element 3. The second port of the throttling element 3 is communicated with the first port of the first heat exchanger 4. The second port of the first heat exchanger 4 is communicated with the suction port of the compressor 1.

[0033] When the CO2 heat pump system of the present application is in operation, the refrigerant (carbon dioxide) discharged by the compressor 1 enters the liquid storage tank 2 through the refrigerant inlet 21 and directly exchanges heat with the liquid in the liquid storage tank 2, so that the liquid in the liquid storage tank 2 is heated. The heat-exchanged refrigerant is discharged through the refrigerant outlet 22 and throttled and depressurized by the throttling element 3, and then enters the first heat exchanger 4 to exchange heat with the air. The heat-exchanged refrigerant flows back to the compressor 1 through the suction port of the compressor 1, and one cycle is completed.

[0034] In the traditional descaling methods in this field, it is usually necessary to add descaling structures and other methods to specifically remove the dirt in the liquid storage tank 2. However, in the CO2 heat pump system of this application, by opening a refrigerant inlet 21 and a refrigerant outlet 22 on the liquid storage tank 2, and connecting the refrigerant inlet 21 and the refrigerant outlet 22 to the exhaust port of the compressor 1 and the first port of the throttling element 3 respectively, it cleverly utilizes the principle that CO2 can react with water scale during operation. By directly exchanging heat between CO2 and the liquid in the liquid storage tank 2, it uses the reaction between CO2 and water scale to prevent scale formation in the liquid storage tank 2. At the same time, since CO2 directly exchanges heat with the liquid, it is beneficial to improve the heat exchange effect, save the setting of the heat exchanger in the liquid storage tank 2, and reduce the equipment cost.

[0035] The following further refers to Figure 1 to introduce the preferred embodiments of this application.

[0036] As Figure 1 shown, in a preferred embodiment, the CO2 heat pump system includes a compressor 1, a four-way valve 5, a liquid storage tank 2, a throttling element 3, a dryer filter 8, a first heat exchanger 4, and a second heat exchanger 7. The four-way valve 5 has four interfaces a, b, c, and d. The exhaust port of the compressor 1 is connected to the interface a of the four-way valve 5, and the suction port of the compressor 1 is connected to the interface d of the four-way valve 5.

[0037] The liquid storage tank 2 is a water tank in this application, and its interior is used to store water for users. For example, the water in the water tank can be used for heating or domestic water supply. The water tank is provided with a liquid inlet 23, a liquid outlet 24, a refrigerant inlet 21, and a refrigerant outlet 22. The liquid inlet 23 is connected to a water source, and the liquid outlet 24 is connected to a water use pipeline. The refrigerant inlet 21 is opened at the bottom of the liquid storage tank 2, and the refrigerant outlet 22 is opened at the top of the liquid storage tank 2. The refrigerant inlet 21 is connected to the interface b of the four-way valve 5. A gas distributor 6 and a flow equalizing plate 12 are arranged in the water tank. The gas distributor 6 is arranged at the bottom of the water tank and is connected to the refrigerant inlet 21 through a pipeline. The flow equalizing plate 12 is arranged in the lower part of the liquid storage tank 2 and above the gas distributor 6. Among them, the gas distributor 6 is used to distribute the refrigerant entering the water tank. Its structure is a conventional means in this field, and any structure that can achieve refrigerant distribution can be applied to this application, and this application will not elaborate. The outer edge of the flow equalizing plate 12 is connected to the inner edge of the water tank. For example, the flow equalizing plate 12 is connected to the water tank by means of bonding, welding, or screwing with the help of a mounting plate. A plurality of flow equalizing holes are opened on its plate body, and the flow equalizing holes are used to perform a flow equalizing operation on the distributed refrigerant, so that the refrigerant exchanges heat evenly with the water in the water tank when rising in the water tank.

[0038] The second heat exchanger 7 preferably adopts a pot - type heat exchanger, which has a cooling inlet 71, a cooling outlet 72, a heat - exchange inlet 73 and a heat - exchange outlet 74. The cooling inlet 71 and the cooling outlet 72 are connected to the tank body of the pot - type heat exchanger. The heat - exchange inlet 73 and the heat - exchange outlet 74 are connected through heat - exchange tubes arranged in the tank body. Among them, the heat - exchange inlet 73 is connected to the refrigerant outlet 22 of the water tank, the cooling outlet 72 is connected to one end of the dryer filter 8, the second port of the dryer filter 8 is connected to the first port of the throttling element 3, the second port of the throttling element 3 is connected to the first port of the first heat exchanger 4, the second port of the first heat exchanger 4 is connected to the heat - exchange inlet 73 of the pot - type heat exchanger, and the heat - exchange outlet 74 of the pot - type heat exchanger is connected to the interface c of the four - way valve 5. Among them, the throttling element 3 is selected as an electronic expansion valve, and the first heat exchanger 4 is equipped with a fan for assisting the heat exchange between the refrigerant and the air.

[0039] Preferably, the second heat exchanger 7 also has a liquid discharge port 75, the liquid discharge port 75 is arranged at the lower part of the tank body of the pot - type heat exchanger, and a liquid discharge pipe 15 is connected to the liquid discharge port 75. The liquid discharge pipe 15 is connected to the liquid inlet 23 of the water tank.

[0040] Furthermore, the CO2 heat - pump system also includes a bypass pipeline 9. The bypass pipeline 9 is arranged inside the liquid storage tank 2. The first end of the bypass pipeline 9 is connected to the pipeline between the exhaust port of the compressor 1 and the refrigerant inlet 21, and more preferably, it is connected to the pipeline between the refrigerant inlet 21 and the gas distributor 6. The second end of the bypass pipeline 9 is connected to the pipeline between the refrigerant outlet 22 and the first port of the throttling element 3, and more preferably, it is connected to the pipeline between the refrigerant outlet 22 and the cooling inlet 71 of the second heat exchanger 7. Among them, a first on - off valve 10 is arranged at the downstream of the pipeline between the exhaust port of the compressor 1 and the refrigerant inlet 21 where the first end of the bypass pipeline 9 is located. In this application, the first on - off valve 10 is arranged on the pipeline between the first end of the bypass pipeline 9 and the gas distributor 6. A second on - off valve 11 is arranged on the bypass pipeline 9, and the second on - off valve 11 is arranged near the second end of the bypass pipeline 9. Preferably, the first on - off valve 10 and the second on - off valve 11 are solenoid valves.

[0041] The operating principle of the CO2 heat - pump system in the preferred embodiment of the present application will be described below.

[0042] As Figure 1As shown in the figure, in the heating mode, the first on-off valve 10 is opened and the second on-off valve 11 is closed. The gaseous refrigerant discharged from the compressor 1 passes through the interfaces a and b of the four-way valve 5 and then enters the water tank through the refrigerant inlet 21. The refrigerant entering the water tank is preliminarily diffused under the action of the gas distributor 6. The diffused gaseous refrigerant rises and is further evenly diffused under the action of the flow equalizing plate 12. The diffused refrigerant continues to rise and exchanges heat with the water in the water tank. After the heat exchange, the temperature of the refrigerant drops and the water temperature rises. The refrigerant after heat exchange is discharged from the water tank through the refrigerant outlet 22 and enters the tank heat exchanger through the cooling inlet 71, where it exchanges heat with the low-temperature refrigerant after passing through the first heat exchanger 4. During the cooling process, the water entrained in the refrigerant condenses and flows back to the liquid inlet 23 of the water tank through the drain pipe 15 and then enters the water tank. The refrigerant with the moisture removed is discharged from the cooling outlet 72 and enters the drying filter 8 for drying to further remove the moisture in the refrigerant. The dried refrigerant enters the electronic expansion valve for throttling and pressure reduction. The refrigerant after throttling and pressure reduction enters the first heat exchanger 4 and exchanges heat with the air with the assistance of the fan. The low-temperature refrigerant after heat exchange enters the tank heat exchanger through the heat exchange inlet 73 to participate in the cooling, and then is discharged through the heat exchange outlet 74, and finally returns to the compressor 1 from the suction port of the compressor 1 after passing through the interfaces c and d of the four-way valve 5, completing the heating cycle.

[0043] When the CO2 heat pump system is used in winter, the first heat exchanger 4 is easily frosted outdoors, and defrosting operation needs to be carried out on the first heat exchanger 4. During defrosting, the first on-off valve 10 is closed, the second on-off valve 11 is opened, and the four-way valve 5 is controlled to change its direction. At this time, the high-temperature refrigerant discharged from the compressor 1 enters the first heat exchanger 4 through the interfaces a and c of the four-way valve 5 to exchange heat with the outdoor air to defrost the first heat exchanger 4. The refrigerant after heat exchange is discharged from the first heat exchanger 4 and then undergoes throttling and pressure reduction through the electronic expansion valve. The refrigerant after throttling and pressure reduction passes through the drying filter 8 and the tank heat exchanger in sequence and then enters the bypass pipeline 9 to exchange heat with the water in the water tank. The refrigerant after heat exchange returns to the compressor 1 after passing through the interfaces b and d of the four-way valve 5, completing the defrosting cycle.

[0044] In the above preferred embodiment, by providing a water tank, direct heat exchange between CO2 and water can be achieved, and the reaction between CO2 and scale is utilized to prevent scaling in the liquid storage tank 2. At the same time, due to the direct heat exchange between CO2 and water, it is beneficial to improve the heat exchange effect, save the setting of the heat exchanger in the water tank, and reduce the equipment cost. By opening the refrigerant inlet 21 at the bottom of the water tank and the refrigerant outlet 22 at the top of the water tank, it is beneficial to enhance the heat exchange effect between CO2 and the liquid. By providing a gas distributor 6 in the water tank, it is beneficial to improve the dispersion effect of CO2 after entering the liquid storage tank 2 and achieve uniform heat exchange between CO2 and the liquid. By providing a flow equalizing plate 12 above the gas distributor 6, the dispersion effect of CO2 can be further improved, and uniform heat exchange between CO2 and the liquid can be achieved. By providing a pot-type heat exchanger, the CO2 after heat exchange in the water tank can be preliminarily cooled, so that the water components doped in the CO2 are separated out, improving the system stability. By providing a drain pipe 15 on the pot-type heat exchanger and connecting the drain pipe 15 to the liquid inlet 23, the separated water can be discharged in time and the separated water can be diverted to the liquid storage tank 2, improving the recycling rate of water. By providing a drying filter 8, the phenomenon of ice blockage of the electronic expansion valve can be avoided, and the operation stability of the system can be improved. By providing a bypass pipeline 9, it is beneficial to defrost the first heat exchanger 4 and at the same time avoid the accumulation of CO2 in the liquid storage tank 2 and unable to circulate.

[0045] It should be noted that the above preferred embodiments are only used to illustrate the principle of the present application and are not intended to limit the protection scope of the present application. Without departing from the principle of the present application, those skilled in the art can adjust the above setting methods so that the present application can be applied to more specific application scenarios.

[0046] For example, in an alternative embodiment, although the above embodiment is described by taking the refrigerant inlet 21 being opened at the bottom of the liquid storage tank 2 and the refrigerant outlet 22 being opened at the top of the liquid storage tank 2 as an example, this is only a relatively preferred embodiment, and those skilled in the art can adjust it as long as the entry and exit of the refrigerant in the liquid storage tank 2 can be achieved. For example, the refrigerant inlet 21 can also be provided at the lower part of the side wall of the liquid storage tank 2, and the refrigerant outlet 22 can also be opened at the upper part of the side wall of the liquid storage tank 2, etc.

[0047] Again, for example, in another alternative embodiment, although the above embodiment is described by combining the provision of a gas distributor 6 in the liquid storage tank 2, the provision of the gas distributor 6 is only preferred, and those skilled in the art can choose whether to provide the gas distributor 6 based on the specific application scenario. For example, in other embodiments, those skilled in the art can omit the provision of the gas distributor 6.

[0048] For another example, in another alternative embodiment, although the above embodiment is described by taking the setting of the flow equalizing plate 12 above the gas distributor 6 as an example, the setting of the flow equalizing plate 12 is not necessary, and those skilled in the art can choose whether to set it based on requirements. Of course, in the case of not setting it, it may affect the heat exchange effect of the refrigerant in the liquid storage tank 2.

[0049] For another example, in another alternative embodiment, although the above embodiment is described by taking the CO2 heat pump system provided with the second heat exchanger 7 as an example, whether to set the second heat exchanger 7 can be selected by those skilled in the art based on the specific application scenario. Of course, those skilled in the art can not set the second heat exchanger 7.

[0050] For another example, in another alternative embodiment, although the second heat exchanger 7 in the above embodiment is described by taking the tank heat exchanger as an example, the specific form of the second heat exchanger 7 is not unique, and those skilled in the art can choose based on requirements. For example, the second heat exchanger 7 can also be a double pipe heat exchanger, a shell and tube heat exchanger, etc.

[0051] For another example, in another alternative embodiment, although the above embodiment is described by taking the liquid discharge port 75 of the second heat exchanger 7 being arranged at the lower part of the tank body as an example, the setting of the liquid discharge port 75 is not necessary, and its setting position is not limited to this either. Those skilled in the art can choose based on the specific application scenario. For example, the liquid discharge port 75 can also not be set, but the tank body can be set as two detachable parts to discharge the condensed water. For example, the liquid discharge port 75 can also be arranged at the lowest point of the bottom of the tank body.

[0052] For another example, in another alternative embodiment, although the above embodiment is described by taking the liquid discharge pipe 15 of the second heat exchanger 7 being communicated with the liquid inlet 23 of the liquid storage tank 2 as an example, the liquid discharge pipe 15 can obviously also not be communicated with the liquid inlet 23. For example, the liquid discharge pipe 15 can also be communicated with the sewer pipe, etc.

[0053] For another example, although the above embodiment is described by taking the water tank provided with the liquid inlet 23 and the liquid outlet 24 as an example, this is only preferred. Those skilled in the art can adjust the structure of the water tank. For example, the water tank can be set as a sealed open-top type to meet the requirements of adding water and taking water, etc.

[0054] For another example, although the above embodiment is described by taking the setting of the drying filter 8 as an example, the setting of the drying filter 8 is not necessary, and those skilled in the art can choose whether to set the drying filter 8 based on specific requirements. For example, when the tank heat exchanger can meet the requirement of removing moisture, the setting of the drying filter 8 can be omitted.

[0055] For another example, although the above-described embodiments are described in conjunction with the bypass pipeline 9 being provided, the provision of the bypass pipeline 9 is not essential. Those skilled in the art can choose whether to provide the bypass pipeline 9 and the specific provision manner of the bypass pipeline 9. Such an adjustment does not deviate from the principle of the present application. For example, in an environment where defrosting is not required, the bypass pipeline 9 can be not provided. At this time, the CO2 heat pump system only operates for heating, and the provision of the corresponding four-way valve 5 can also be omitted. For another example, on the premise of providing the bypass pipeline 9, the bypass pipeline 9 can also be provided outside the liquid storage tank 2, and heat exchange of the refrigerant can be achieved by configuring a blower or the like.

[0056] For another example, although the above-described embodiments are introduced in conjunction with the first on-off valve 10 and the second on-off valve 11 being solenoid valves, the specific structural forms and installation positions of the two can be adjusted. Those skilled in the art can make flexible selections based on requirements. For example, the first on-off valve 10 and the second on-off valve 11 can be selected as manual valves, or other valves that can be automatically controlled, such as electric butterfly valves, electric ball valves, etc. For another example, the first on-off valve 10 can also be provided outside the liquid storage tank 2, as long as it is downstream of the first end of the bypass pipeline 9. For another example, the second on-off valve 11 can also be provided at the first end of the bypass pipeline 9 or the like.

[0057] Certainly, the above-described alternative embodiments, as well as between the alternative embodiments and the preferred embodiments, can be used in cross combination, so as to combine new embodiments to be applicable to more specific application scenarios.

[0058] In addition, those skilled in the art can understand that although some of the embodiments described herein include certain features included in other embodiments rather than other features, the combination of the features of different embodiments means that it is within the scope of the present application and forms different embodiments. For example, in the claims of the present application, any one of the claimed embodiments can be used in any combination manner.

[0059] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principle of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present application.

Claims

1. A CO2 heat pump system, characterized in that, The CO2 heat pump system includes a compressor, a liquid storage tank, a throttling element, and a first heat exchanger. The liquid storage tank has a receiving cavity, and a refrigerant inlet and a refrigerant outlet are provided on the liquid storage tank. The refrigerant inlet and the refrigerant outlet are communicated through the receiving cavity. The exhaust port of the compressor is communicated with the refrigerant inlet, the refrigerant outlet is communicated with the first port of the throttling element, the second port of the throttling element is communicated with the first port of the first heat exchanger, and the second port of the first heat exchanger is communicated with the suction port of the compressor.

2. The CO2 heat pump system according to claim 1, wherein The refrigerant inlet is provided at the bottom of the liquid storage tank, and / or the refrigerant outlet is provided at the top of the liquid storage tank.

3. The CO2 heat pump system according to claim 1, characterized in that, The CO2 heat pump system further includes a gas distributor, and the gas distributor is arranged inside the liquid storage tank and communicated with the refrigerant inlet.

4. The CO2 heat pump system according to claim 3, characterized in that, The CO2 heat pump system further includes a flow equalizing plate, and the flow equalizing plate is arranged inside the liquid storage tank and above the gas distributor.

5. The CO2 heat pump system according to claim 1, characterized in that, The CO2 heat pump system further includes a second heat exchanger, and the second heat exchanger has a cooling inlet, a cooling outlet, a heat exchange inlet, and a heat exchange outlet. The heat exchange inlet is communicated with the refrigerant outlet, the cooling outlet is communicated with the first port of the throttling element, the heat exchange inlet is communicated with the second port of the first heat exchanger, and the heat exchange outlet is communicated with the suction port of the compressor.

6. The CO2 heat pump system according to claim 5, characterized in that, The second heat exchanger further has a liquid discharge port, and a liquid discharge pipe is connected to the liquid discharge port.

7. The CO2 heat pump system according to claim 6, wherein, The liquid storage tank has a liquid inlet and a liquid outlet, and the liquid discharge pipe is communicated with the liquid inlet.

8. The CO2 heat pump system according to claim 5, characterized in that, The CO2 heat pump system further includes a dryer filter, and the first port of the dryer filter is communicated with the cooling outlet, and the second port of the dryer filter is communicated with the first port of the throttling element.

9. The CO2 heat pump system according to claim 1, characterized in that The CO2 heat pump system further includes a bypass pipeline. The first end of the bypass pipeline is communicated with the pipeline between the exhaust port of the compressor and the refrigerant inlet, and the second end of the bypass pipeline is communicated with the pipeline between the refrigerant outlet and the first port of the throttling element. A first on-off valve is provided on the pipeline between the exhaust port of the compressor and the refrigerant inlet downstream of the first end of the bypass pipeline, and a second on-off valve is provided on the bypass pipeline.

10. The CO2 heat pump system according to claim 9, wherein, The bypass pipeline is arranged inside the liquid storage tank.

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