CN212657900U

CN212657900U - Refrigerant circulation system and air conditioning unit

Info

Publication number: CN212657900U
Application number: CN202021954137.8U
Authority: CN
Inventors: 卓明胜; 黄成武; 周宇; 刘贤权
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2020-09-09
Filing date: 2020-09-09
Publication date: 2021-03-05
Anticipated expiration: 2030-09-09

Abstract

The disclosure relates to a refrigerant circulating system and an air conditioning unit. The refrigerant circulation system includes: a first compressor (1) comprising a housing (10), a compressor rotor (12) and an air suspension bearing (13) supporting the compressor rotor (12); the air storage tank (6) is communicated with an air inlet path of the air suspension bearing (13) through an air inlet pipe and is configured to provide gaseous refrigerant to the air suspension bearing (13); the second compressor (5) is provided with a suction end and a discharge end communicated with the air storage tank (6), and the suction end of the second compressor (5) is connected with a plurality of positions with different working pressures in a refrigerant circulation loop (A) where the first compressor (1) is located through a plurality of suction paths; and a switching device (8) connected to the plurality of intake paths and configured to selectively communicate the intake end of the second compressor (5) with one of the plurality of positions through the corresponding intake path. The embodiment of the disclosure can improve the adaptability of air supply of the air suspension bearing.

Description

Refrigerant circulation system and air conditioning unit

Technical Field

The disclosure relates to the field of compressors, in particular to a refrigerant circulating system and an air conditioning unit.

Background

The static pressure gas suspension centrifugal compressor is a compressor which lifts a rotor away from a bearing by utilizing buoyancy generated by high-pressure gas so as to realize rotor suspension. The compressor has the advantages of small friction loss, small volume, no oil and the like. Compared with an oil lubrication bearing, the bearing capacity of the gas suspension bearing is small and easy to wear, and the stability of the gas supply quantity of the gas bearing can be ensured so as to provide sufficient buoyancy and provide necessary conditions for stable operation of the gas suspension compressor.

In the related art known by the inventor, the gas in the evaporator is pressurized by another gas supply compressor besides the gas suspension compressor and then is supplied to the gas storage tank, and finally is supplied to the gas suspension bearing in the gas suspension compressor.

Disclosure of Invention

Research shows that in the running process of the water chilling unit, the air supply amount required by the air bearing suspension is increased along with the reduction of the rotating speed of the air suspension compressor. Since the evaporator pressure is the lowest pressure in the unit system, the amount of air supplied by the air supply compressor decreases as the evaporator pressure decreases. This causes the related art to have difficulty in ensuring the stability of the gas bearing supply amount when operating under the unfavorable conditions of low rotational speed and low pressure, and thus the stable operation of the gas suspension compressor cannot be maintained. Under some operating conditions, the problems that the air supply amount of the air supply compressor is too much, the consumed power is increased, and the operating energy efficiency of the water chilling unit is reduced can also occur.

In view of this, the present disclosure provides a refrigerant circulation system and an air conditioning unit, which can improve the adaptability of air supply for an air suspension bearing.

In one aspect of the present disclosure, there is provided a refrigerant circulation system including:

the first compressor comprises a shell, a compressor rotor positioned in the shell and an air suspension bearing positioned in the shell and used for supporting the compressor rotor;

the air storage tank is communicated with an air inlet path of the air suspension bearing through an air inlet pipe and is configured to provide gaseous refrigerant to the air suspension bearing;

the second compressor is provided with a gas suction end and a gas exhaust end communicated with the gas storage tank, and the gas suction end of the second compressor is connected with a plurality of positions with different working pressures in a refrigerant circulation loop where the first compressor is located through a plurality of gas suction channels;

a switching device connected to the plurality of suction paths and configured to selectively communicate a suction end of the second compressor with one of the plurality of locations through the corresponding suction path.

In some embodiments, the refrigerant circulation system further includes:

the condenser is positioned in a refrigerant circulating loop where the first compressor is positioned and is communicated with an exhaust port of the first compressor;

the evaporator is positioned in a refrigerant circulating loop where the first compressor is positioned and is communicated with an air suction port of the first compressor;

the air suction channels comprise a first air suction channel and a second air suction channel, the condenser is communicated with the air storage tank through the first air suction channel, the evaporator is connected with the air storage tank through the second air suction channel, and the working pressure of the condenser is higher than that of the evaporator.

In some embodiments, the air storage tank communicates with the evaporator through a bypass pipe, and the refrigerant circulation system further includes:

a first control valve located in the bypass line and configured to regulate a flow of gaseous refrigerant bypassed from the accumulator to the evaporator.

In some embodiments, the refrigerant circulation system further includes a flash evaporator located in the refrigerant circulation loop where the first compressor is located, the plurality of gas suction channels further include a third gas suction channel, the flash evaporator is connected to the gas storage tank through the third gas suction channel, and a working pressure of the flash evaporator is lower than a working pressure of the condenser and higher than a working pressure of the evaporator.

In some embodiments, the gas extraction port of the first gas extraction path on the condenser is located at the upper part of the condenser, the second gas extraction path is located at the upper side of the liquid baffle of the evaporator at the gas extraction port of the evaporator, and the third gas extraction path is located at the upper side of the gas-liquid separation net of the flash evaporator at the gas extraction port of the flash evaporator.

In some embodiments, the switching device comprises:

a second control valve provided on the first suction path and configured to connect or disconnect the first suction path;

a third control valve provided in the second intake passage and configured to connect or disconnect the second intake passage;

a fourth control valve provided in the third intake passage and configured to connect or disconnect the third intake passage;

wherein, the gas holder with the evaporimeter passes through the bypass pipe intercommunication, refrigerant circulation system still includes:

a first control valve located in the bypass pipe and configured to regulate a flow rate of the gaseous refrigerant bypassed from the gas tank to the evaporator;

and a controller, which is in signal connection with the first control valve, the second control valve, the third control valve and the fourth control valve, and is configured to switch one of the second control valve, the third control valve and the fourth control valve to a connected state and the other to a disconnected state according to a system air supply pressure difference of the refrigerant circulation system, and adjust an opening degree of the first control valve according to the system air supply pressure difference.

In some embodiments, the first control valve comprises an electronic expansion valve, a solenoid operated regulator valve, or an electrically operated regulator valve, and each of the second control valve, the third control valve, and the fourth control valve comprises a solenoid on-off valve, an electronic expansion valve, or an electrically operated butterfly valve.

In some embodiments, the refrigerant circulation system further includes:

a first pressure sensor disposed inside the gas tank, configured to detect a pressure of the gas tank,

a second pressure sensor disposed in a motor cavity of the first compressor and configured to detect a pressure of the motor cavity;

and the controller is in signal connection with the first pressure sensor, the second pressure sensor and the switching device, is configured to use the pressure difference between the air storage tank and the motor cavity as the system air supply pressure difference of the refrigerant circulating system, and controls the switching device to switch the air suction channel according to the system air supply pressure difference.

In some embodiments, the refrigerant circulation system further includes:

a first pressure sensor disposed inside the gas tank, configured to detect a pressure of the gas tank;

a third pressure sensor provided on the evaporator, configured to detect a pressure of the evaporator;

and the controller is in signal connection with the first pressure sensor, the second pressure sensor, the third pressure sensor, the first control valve and the switching device, is configured to control the switching device to switch the air suction path according to the system air supply pressure difference by taking the pressure difference between the air storage tank and the motor cavity, the pressure difference between the air storage tank and an air suction port of the first compressor or the pressure difference between the air storage tank and the evaporator as the system air supply pressure difference of the refrigerant circulating system, and adjusts the opening degree of the first control valve.

In some embodiments, the first compressor comprises a two-stage compressor having a first-stage impeller and a second-stage impeller, and the refrigerant circulation system further comprises: the flash evaporator comprises a first throttler and a second throttler, wherein the first throttler is connected between a condenser and an inlet of the flash evaporator, the second throttler is connected between a liquid outlet of the flash evaporator and an evaporator, and a gas outlet of the flash evaporator is connected with a compression inlet of a secondary impeller, so that a gas refrigerant discharged by the flash evaporator and a compressed gas refrigerant discharged by a compression outlet of a primary impeller jointly enter a compression inlet of the secondary impeller.

In some embodiments, a return pipe for returning the gas refrigerant in the motor cavity to the evaporator is further provided between the motor cavity of the first compressor and the evaporator.

In one aspect of the present disclosure, there is provided an air conditioning unit including: the above-mentioned refrigerant circulation system.

Therefore, according to the embodiment of the disclosure, the connection relationship between the suction end of the second compressor serving as the air supply compressor and the positions of different working pressures in the refrigerant circulation loop where the first compressor is located is switched by the switching device, so that the air supply amount of the second compressor can be adjusted according to actual needs, the air supply requirement of the air suspension bearing is met, and the stable operation of the first compressor is ensured.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description, serve to explain the principles of the disclosure.

The present disclosure may be more clearly understood from the following detailed description, taken with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of some embodiments of a coolant circulation system according to the present disclosure;

FIG. 2 is a schematic diagram of a refrigerant circulation system according to some embodiments of the present disclosure;

fig. 3 is a schematic diagram of control relationships of some embodiments of a refrigerant circulation system according to the present disclosure.

It should be understood that the dimensions of the various parts shown in the figures are not drawn to scale. Further, the same or similar reference numerals denote the same or similar components.

Detailed Description

Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the disclosure, its application, or uses. The present disclosure may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that: the relative arrangement of parts and steps, the composition of materials, numerical expressions and numerical values set forth in these embodiments are to be construed as merely illustrative, and not as limitative, unless specifically stated otherwise.

The use of "first," "second," and similar terms in this disclosure is not intended to indicate any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element preceding the word covers the element listed after the word, and does not exclude the possibility that other elements are also covered. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

In the present disclosure, when a specific device is described as being located between a first device and a second device, there may or may not be intervening devices between the specific device and the first device or the second device. When a particular device is described as being coupled to other devices, that particular device may be directly coupled to the other devices without intervening devices or may be directly coupled to the other devices with intervening devices.

All terms (including technical or scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs unless specifically defined otherwise. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

Fig. 1 is a schematic diagram of some embodiments of a refrigerant circulation system according to the present disclosure. Fig. 2 is a schematic structural diagram of some embodiments of a refrigerant circulation system according to the present disclosure. Referring to fig. 1 and 2, in some embodiments, the refrigerant circulation system includes: the compressor comprises a first compressor 1, an air storage tank 6, a second compressor 5 and a switching device 8. The first compressor 1 comprises a housing 10, a compressor rotor 12 located within said housing 10 and an air suspension bearing 13 located within said housing 10 and supporting said compressor rotor 12. In some embodiments, the first compressor 1 is a static pressure air-suspension centrifugal compressor and the air-suspension bearing 13 is a static pressure air-suspension bearing.

The gas tank 6 communicates with an intake passage of the gas bearing 13 through an intake pipe, and is configured to supply a gaseous refrigerant to the gas bearing 13. The second compressor 5 is provided with a suction end and a discharge end communicated with the gas storage tank 6, and the suction end of the second compressor 5 is connected with a plurality of positions with different working pressures in the refrigerant circulation loop A where the first compressor 1 is located through a plurality of suction paths. The second compressor is used as a gas supply compressor to pressurize the refrigerant and then discharge the refrigerant into the gas storage tank, and finally high-pressure gas in the gas storage tank is supplied to the gas suspension bearing, so that sufficient buoyancy is generated to lift the compressor rotor away from the gas suspension bearing, and the purpose of suspending the compressor rotor is achieved.

The switching device 8 is connected to the plurality of suction paths, and is configured to selectively communicate the suction end of the second compressor 5 with one of the plurality of positions through the corresponding suction path. Here, the working pressures at the plurality of connection positions of the refrigerant circuit a in which the first compressor 1 is located are different. The working pressure refers to the pressure at the corresponding position of the first compressor 1 in the operating state.

In fig. 1, the refrigerant circulation circuit a in which the first compressor 1 is located is schematically represented by thick solid black lines, and the plurality of suction paths B1, B2, and B3 to which the suction end of the second compressor 5 is connected are indicated by thin dashed-dotted lines. It should be noted that the positions and connection relationships of the condenser, the flash tank, the evaporator and the first compressor in the refrigerant circulation circuit a are only schematic in fig. 1.

In this embodiment, the switching device switches the connection relationship between the suction end of the second compressor serving as the air supply compressor and the positions of different working pressures in the refrigerant circulation loop where the first compressor is located, so that the air supply amount of the second compressor can be adjusted according to actual needs, the air supply requirement of the air suspension bearing is met, and the stable operation of the first compressor is ensured.

In fig. 1 and 2, the refrigerant circulation system further includes: a condenser 2 and an evaporator 3. The condenser 2 is located in the refrigerant circulation circuit a where the first compressor 1 is located, and is communicated with the exhaust port of the first compressor 1. The evaporator 3 is located in a refrigerant circulation circuit a in which the first compressor 1 is located, and is communicated with a suction port of the first compressor 1. Accordingly, the plurality of suction paths include a first suction path B1 and a second suction path B2, the condenser 2 is communicated with the air tank 6 through the first suction path B1, the evaporator 3 is connected with the air tank 6 through the second suction path B2, and the operating pressure of the condenser 2 is higher than that of the evaporator 3.

Under the refrigeration working condition, the working pressure of the evaporator 3 is smaller than that of the condenser 2. Under the condition of meeting the air supply requirement of the air suspension bearing, the air suction end of the second compressor 5 can be connected with the evaporator 3 with lower working pressure through the second air suction channel B2, so that the power consumption of the second compressor 5 is reduced, and the energy efficiency of the air conditioning unit applied to the refrigerant circulating system is improved. When some unfavorable conditions occur, for example, when the first compressor 1 is in a low-speed and low-pressure working state, the working pressure of the evaporator 3 is correspondingly reduced, so that the air supply amount of the second compressor is insufficient, at this time, the air suction end of the second compressor can be switched to be connected with the condenser 2 with higher working pressure through the switching device 8, so that the air supply amount of the second compressor is increased, the stable operation of the air suspension bearing is ensured, and the stable operation of the first compressor is ensured.

Referring to fig. 1 and 2, in some embodiments, the air reservoir 6 communicates with the evaporator 3 through a bypass pipe C. The refrigerant circulation system further includes a first control valve 7 located at the bypass pipe C. The first control valve 7 can adjust the flow rate of the gaseous refrigerant bypassing the gas tank 6 to the evaporator 3. The bypass gaseous refrigerant flow is adjusted through the first control valve 7, so that the pressure of the gas storage tank 6 can be adjusted and stabilized, and the gas supply pressure of the gas suspension bearing can be adjusted and stabilized.

In some embodiments, the second compressor may be a fixed flow compressor, which by itself does not directly adjust the amount of supplied air, and accordingly adjustment of the amount of supplied air is achieved by the first control valve 7. The first control valve 7 may comprise an electronic expansion valve, an electromagnetic regulating valve or an electric regulating valve. One or more first control valves 7 may be provided on the bypass pipe C as required.

Referring to fig. 2, in some embodiments, a return pipe 14 for returning the gas refrigerant in the motor cavity to the evaporator 3 is further disposed between the motor cavity of the first compressor 1 and the evaporator 3. The return pipe 14 can be a metal pipe, such as a copper pipe, for communicating the bottom of the motor cavity with the evaporator 3.

In fig. 1 and 2, the refrigerant circulation system may further include a flash tank 4 in the refrigerant circulation loop a of the first compressor 1. Accordingly, the plurality of suction paths further includes a third suction path B3. The flash tank 4 is connected with the air storage tank 6 through the third air suction channel B3, and the working pressure of the flash tank 4 is lower than that of the condenser 2 and higher than that of the evaporator 3. In other words, the operating pressure of the flash tank 4 is intermediate between the evaporator 3 and the condenser 2.

Therefore, under the condition that the air supply quantity of the air suspension bearing can be guaranteed to be stable, the lower the air inlet pressure of the second compressor is, the lower the power consumption is, and the energy efficiency of the air conditioning unit is improved. Therefore, the intake air from the evaporator can be preferentially selected. When the air supply pressure difference cannot meet the pressure difference required by the air suspension bearing, air can be switched to be supplied from the flash tank. If the supply air pressure difference still cannot meet the pressure difference required by the air suspension bearing, switching to the air intake from the condenser is performed. For the second compressor, the higher the intake pressure, the higher the supply pressure that can be achieved, so the supply pressure can be effectively increased by replacing the suction position of the suction end.

In other embodiments, the suction end of the second compressor may take gas from other positions of the refrigerant circulation circuit a of the first compressor, such as a gas-liquid separator, an oil separator, and the like.

In specific connection, the first air suction channel B1, the second air suction channel B2 and the third air suction channel B3 may be connected by metal tubes (e.g., copper tubes, etc.). In some embodiments, the gas extraction opening of first suction line B1 on the condenser 2 may be located at the upper portion of the condenser 2. The second gas suction channel B2 at the gas extraction port of the evaporator 3 may be located on the upper side of the liquid baffle of the evaporator 3, and the third gas suction channel B3 at the gas extraction port of the flash tank 4 may be located on the upper side of the gas-liquid separation net of the flash tank 4. Through the arrangement, the gaseous refrigerant entering the second compressor is prevented from carrying liquid drops, so that the second compressor is prevented from sucking air and carrying liquid.

Fig. 3 is a schematic diagram of control relationships of some embodiments of a refrigerant circulation system according to the present disclosure. In order to facilitate the switching of the suction side of the second compressor, with reference to fig. 2 and 3, in a shorter embodiment, the switching device 8 comprises: a second control valve 83, a third control valve 81 and a fourth control valve 82. The second control valve 83 is disposed on the first suction path B1 and configured to turn on or off the first suction path B1. The third control valve 81 is disposed on the second suction path B2 and configured to turn on or off the second suction path B2. The fourth control valve 82 is disposed on the third suction path B3, and is configured to turn on or off the third suction path B3. The on-off switching of different air suction paths can be realized by opening and closing one part and the other part of the second control valve 83, the third control valve 81 and the fourth control valve 82.

In some embodiments, each of the second control valve 83, the third control valve 81, and the fourth control valve 82 comprises a solenoid on-off valve, an electronic expansion valve, or an electrically-operated butterfly valve. Accordingly, in addition to the on/off of the air suction path, the second control valve 83, the third control valve 81 and the fourth control valve 82 can also control the pressure and flow of the air suction path as required.

Referring to fig. 3, the refrigerant circulation system further includes a controller 9. The controller 9 is in signal connection with the first control valve 7, the second control valve 83, the third control valve 81, and the fourth control valve 82, and is configured to switch one of the second control valve 83, the third control valve 81, and the fourth control valve 82 to a connected state and the other to a disconnected state according to a system air supply pressure difference of the refrigerant circulation system, and adjust the opening degree of the first control valve 7 according to the system air supply pressure difference.

Referring to fig. 2 and 3, in some embodiments, the refrigerant circulation system further includes: a first pressure sensor 61 and a second pressure sensor 11. The first pressure sensor 61 is provided inside the gas tank 6, and is configured to detect the pressure of the gas tank 6. A second pressure sensor 11 is arranged in the motor cavity of the first compressor 1, configured to detect the pressure in the motor cavity. The controller 9 is signally connectable to said first pressure sensor 61, said second pressure sensor 11 and said switching device 8. The controller 9 may use a pressure difference between the air storage tank 6 and the motor cavity as a system air supply pressure difference of the refrigerant circulation system, and control the switching device 8 to switch the air suction path according to the system air supply pressure difference.

In other embodiments, the pressure difference at other positions may also be used as the system air supply pressure difference of the refrigerant circulation system. For example, the system air supply pressure difference of the refrigerant cycle system is set to a pressure difference between the air tank 6 and the air inlet of the first compressor 1 or a pressure difference between the air tank 6 and the evaporator 3. The refrigerant circulation system may further include a third pressure sensor 31 as necessary. A third pressure sensor 31 is provided on the evaporator 3, and is configured to detect the pressure of the evaporator 3.

The controller 9 may be in signal connection with the first pressure sensor 61, the second pressure sensor 11, the third pressure sensor 31, the first control valve 7, and the switching device 8, and may control the switching device 8 to switch the air suction path and adjust the opening degree of the first control valve 7 according to the system air supply pressure difference, using the pressure difference between the air storage tank 6 and the motor cavity, the pressure difference between the air storage tank 6 and the air suction port of the first compressor 1, or the pressure difference between the air storage tank 6 and the evaporator 3 as the system air supply pressure difference of the refrigerant circulation system.

In some embodiments, the first compressor 1 comprises a two-stage compressor having a one-stage impeller and a two-stage impeller. The refrigerant circulation system further includes: the flash evaporator comprises a first throttler and a second throttler, wherein the first throttler is connected between the condenser 2 and an inlet of the flash evaporator 4, the second throttler is connected between a liquid outlet of the flash evaporator 4 and the evaporator 3, and a gas outlet of the flash evaporator 4 is connected with a compression inlet of the secondary impeller, so that a gas refrigerant discharged by the flash evaporator 4 and a compressed gas refrigerant discharged by a compression outlet of the primary impeller jointly enter the compression inlet of the secondary impeller.

The embodiment of the refrigerant circulating system can be applied to various air conditioning units, such as a cold water air conditioning unit. Correspondingly, the embodiment of the disclosure also provides an air conditioning unit, which comprises any one of the embodiments of the refrigerant circulation system. In some embodiments, the air conditioning packs comprise chilled water air conditioning packs.

In some embodiments, the control flow based on the aforementioned refrigerant circulation system embodiment includes: acquiring system air supply pressure difference of the refrigerant circulating system; according to the system air supply pressure difference, the switching device 8 is used for selectively communicating the air suction end of the second compressor 5 with one of a plurality of positions with different working pressures in the refrigerant circulation loop A where the first compressor 1 is located through a corresponding air suction path.

In this embodiment, the switching device switches the connection relationship between the suction end of the second compressor serving as the air supply compressor and the positions of different working pressures in the refrigerant circulation loop where the first compressor is located, so that the air supply amount of the second compressor can be adjusted according to the air supply pressure difference of the system, the air supply requirement of the air suspension bearing is met, and the stable operation of the first compressor is ensured.

In some embodiments, the method includes receiving an instruction to start the second compressor while the second compressor is in an off state; after receiving the instruction to start the second compressor 5, the switching device 8 connects the suction end of the second compressor 5 to the lowest pressure position among the plurality of positions having different working pressures through the corresponding suction path. For example, the refrigerant circuit a of the first compressor communicates with an evaporator having a relatively low pressure. And the power consumption of the second compressor is reduced through the air inlet pressure of the second compressor, so that the energy efficiency of the air conditioning unit is improved.

In some embodiments, the refrigerant circulation system further includes a condenser 2, an evaporator 3, and a flash tank 4 in the refrigerant circulation loop a where the first compressor 1 is located, the working pressure of the condenser 2 is higher than the working pressure of the evaporator 3, and the working pressure of the flash tank 4 is lower than the working pressure of the condenser 2 and higher than the working pressure of the evaporator 3. The air storage tank 6 is communicated with the evaporator 3 through a bypass pipe C, and the refrigerant circulating system further includes a first control valve 7 located in the bypass pipe C.

In this embodiment, the control flow further includes: after the second compressor 5 is started, the flow rate of the gaseous refrigerant bypassing the gas storage tank 6 to the evaporator 3 is adjusted through the first control valve 7, so as to adjust the pressure of the gas storage tank 6; and obtaining the actual maximum value of the system air supply pressure difference, wherein the actual maximum value of the system air supply pressure difference is the actual system air supply pressure difference when the first control valve 7 is in a completely closed state.

In order to obtain the actual maximum value of the system air supply pressure difference, in some embodiments, the first control valve 7 may be in a completely closed state, the pressure difference between the air storage tank 6 and the motor cavity, between the air storage tank 6 and the suction port of the first compressor 1, or between the air storage tank 6 and the evaporator 3 may be calculated, and the calculation result may be used as the actual maximum value of the system air supply pressure difference.

The control flow further comprises: and judging whether the actual maximum value Pmax of the system air supply pressure difference is smaller than the set air supply pressure difference Ps. If the actual maximum value Pmax of the system air supply pressure difference is less than the set air supply pressure difference Ps and the air suction end of the second compressor 5 is communicated with the evaporator 3 at present, the air suction end of the second compressor 5 is switched to be communicated with the flash tank 4 through the switching device 8.

If the actual maximum value Pmax of the system air supply pressure difference is less than the set air supply pressure difference Ps and the air suction end of the second compressor 5 is currently communicated with the flash tank 4, the air suction end of the second compressor 5 is switched to be communicated with the condenser 2 through the switching device 8.

Through the switching action of the switching device, the air inlet pressure of the second compressor can be adjusted when the air supply pressure difference of the system is insufficient, so that the air supply pressure difference of the system is improved, and the condition of setting the air supply pressure difference is met. In some embodiments, the set air supply pressure difference may be 200 to 600 KPa.

If the actual maximum value Pmax of the system air supply pressure difference is equal to the set air supply pressure difference Ps, the current air supply state can be maintained without switching. If the actual maximum value Pmax of the system air supply pressure difference is smaller than the set air supply pressure difference Ps, the air suction end of the second compressor can be kept at the current air suction position or switched to other air suction positions with lower working pressure according to the situation, so that the energy consumption of the second compressor is reduced.

In some embodiments, the refrigerant circulation system may not include a flash tank. For example, the refrigerant cycle system further includes a condenser 2 and an evaporator 3 in the refrigerant cycle circuit a in which the first compressor 1 is located, and the operating pressure of the condenser 2 is higher than that of the evaporator 3. The air storage tank 6 is communicated with the evaporator 3 through a bypass pipe C, and the refrigerant circulating system further includes a first control valve 7 located in the bypass pipe C. Correspondingly, the control flow further comprises: and judging whether the actual maximum value of the air supply pressure difference of the system is smaller than the set air supply pressure difference. When the actual maximum value of the system air supply pressure difference is smaller than the set air supply pressure difference and the air suction end of the second compressor 5 is currently communicated with the evaporator 3, the switching device 8 can be used for switching the air suction end of the second compressor 5 to be communicated with the condenser 2.

Thus, various embodiments of the present disclosure have been described in detail. Some details that are well known in the art have not been described in order to avoid obscuring the concepts of the present disclosure. It will be fully apparent to those skilled in the art from the foregoing description how to practice the presently disclosed embodiments.

Although some specific embodiments of the present disclosure have been described in detail by way of example, it should be understood by those skilled in the art that the foregoing examples are for purposes of illustration only and are not intended to limit the scope of the present disclosure. It will be understood by those skilled in the art that various changes may be made in the above embodiments or equivalents may be substituted for elements thereof without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A refrigerant circulation system, comprising:

a first compressor (1) comprising a housing (10), a compressor rotor (12) located within the housing (10), and an air suspension bearing (13) located within the housing (10) and supporting the compressor rotor (12);

the air storage tank (6) is communicated with an air inlet path of the air suspension bearing (13) through an air inlet pipe and is configured to provide gaseous refrigerant to the air suspension bearing (13);

the second compressor (5) is provided with a suction end and a discharge end communicated with the air storage tank (6), and the suction end of the second compressor (5) is connected with a plurality of positions with different working pressures in a refrigerant circulation loop (A) where the first compressor (1) is located through a plurality of suction paths;

a switching device (8) connected to the plurality of suction paths and configured to selectively communicate a suction end of the second compressor (5) with one of the plurality of positions through the corresponding suction path.

2. The refrigerant circulation system as claimed in claim 1, further comprising:

a condenser (2) which is positioned in a refrigerant circulation loop (A) where the first compressor (1) is positioned and is communicated with an exhaust port of the first compressor (1);

the evaporator (3) is positioned in a refrigerant circulating loop (A) where the first compressor (1) is positioned and is communicated with a suction port of the first compressor (1);

the air suction paths comprise a first air suction path (B1) and a second air suction path (B2), the condenser (2) is communicated with the air storage tank (6) through the first air suction path (B1), the evaporator (3) is connected with the air storage tank (6) through the second air suction path (B2), and the working pressure of the condenser (2) is higher than that of the evaporator (3).

3. The refrigerant cycle system as claimed in claim 2, wherein the air tank (6) communicates with the evaporator (3) through a bypass pipe (C), the refrigerant cycle system further comprising:

a first control valve (7) located at the bypass pipe (C) and configured to regulate the flow rate of the gaseous refrigerant bypassing the air storage tank (6) to the evaporator (3).

4. The refrigerant circulation system according to claim 2, further comprising a flash tank (4) in the refrigerant circulation circuit (a) in which the first compressor (1) is located, wherein the plurality of gas suction channels further include a third gas suction channel (B3), the flash tank (4) is connected to the gas storage tank (6) through the third gas suction channel (B3), and a working pressure of the flash tank (4) is lower than a working pressure of the condenser (2) and higher than a working pressure of the evaporator (3).

5. The refrigerant circulation system as claimed in claim 4, wherein the gas extraction opening of the first gas extraction path (B1) on the condenser (2) is located at the upper part of the condenser (2), the gas extraction opening of the second gas extraction path (B2) on the evaporator (3) is located at the upper side of the liquid baffle of the evaporator (3), and the gas extraction opening of the third gas extraction path (B3) on the flash evaporator (4) is located at the upper side of the gas-liquid separation net of the flash evaporator (4).

6. The coolant circulation system according to claim 4, characterized in that the switching device (8) comprises:

a second control valve (83) provided on the first suction path (B1) and configured to turn on or off the first suction path (B1);

a third control valve (81) provided on the second suction path (B2) and configured to turn on or off the second suction path (B2);

a fourth control valve (82) provided on the third suction path (B3) and configured to turn on or off the third suction path (B3);

wherein, the gas holder (6) with evaporimeter (3) are through bypass pipe (C) intercommunication, refrigerant circulation system still includes:

a first control valve (7) located at the bypass pipe (C) and configured to regulate the flow rate of the gaseous refrigerant bypassing the gas storage tank (6) to the evaporator (3);

and a controller (9) which is in signal connection with the first control valve (7), the second control valve (83), the third control valve (81) and the fourth control valve (82), and is configured to switch one of the second control valve (83), the third control valve (81) and the fourth control valve (82) to a connected state and the other to a disconnected state according to a system air supply pressure difference of the refrigerant circulation system, and to adjust the opening degree of the first control valve (7) according to the system air supply pressure difference.

7. The refrigerant cycle system according to claim 6, wherein the first control valve (7) comprises an electronic expansion valve, an electromagnetic regulating valve, or an electric regulating valve, and each of the second control valve (83), the third control valve (81), and the fourth control valve (82) comprises an electromagnetic on-off valve, an electronic expansion valve, or an electric butterfly valve.

8. The refrigerant circulation system as claimed in claim 1, further comprising:

a first pressure sensor (61) disposed inside the air tank (6) configured to detect a pressure of the air tank (6),

a second pressure sensor (11) provided in a motor cavity of the first compressor (1) and configured to detect a pressure of the motor cavity;

and the controller (9) is in signal connection with the first pressure sensor (61), the second pressure sensor (11) and the switching device (8), and is configured to use the pressure difference between the air storage tank (6) and the motor cavity as the system air supply pressure difference of the refrigerant circulating system and control the switching device (8) to switch the air suction channel according to the system air supply pressure difference.

9. The coolant circulation system according to claim 3, further comprising:

a first pressure sensor (61) disposed inside the gas tank (6) configured to detect a pressure of the gas tank (6);

a third pressure sensor (31) provided on the evaporator (3) and configured to detect a pressure of the evaporator (3);

and the controller (9) is in signal connection with the first pressure sensor (61), the second pressure sensor (11), the third pressure sensor (31), the first control valve (7) and the switching device (8), is configured to use the pressure difference between the air storage tank (6) and the motor cavity, the pressure difference between the air storage tank (6) and an air suction port of the first compressor (1) or the pressure difference between the air storage tank (6) and the evaporator (3) as the system air supply pressure difference of the refrigerant circulating system, controls the switching device (8) to switch air suction channels according to the system air supply pressure difference, and adjusts the opening degree of the first control valve (7).

10. The refrigerant circulation system according to claim 4, wherein the first compressor (1) comprises a two-stage compressor having a first-stage impeller and a second-stage impeller, the refrigerant circulation system further comprising: the flash evaporator comprises a first throttler and a second throttler, wherein the first throttler is connected between the condenser (2) and an inlet of the flash evaporator (4), the second throttler is connected between a liquid outlet of the flash evaporator (4) and an evaporator (3), and a gas outlet of the flash evaporator (4) is connected with a compression inlet of the secondary impeller, so that a gas refrigerant discharged by the flash evaporator (4) and a compressed gas refrigerant discharged by a compression outlet of the primary impeller jointly enter the compression inlet of the secondary impeller.

11. The refrigerant cycle system according to claim 2, wherein a return pipe (14) for returning the gas refrigerant in the motor cavity to the evaporator (3) is further provided between the motor cavity of the first compressor (1) and the evaporator (3).

12. An air conditioning assembly, comprising:

the refrigerant circulation system according to any one of claims 1 to 11.