Refrigerant circulation module capable of recycling expansion work and energy storage heat management system

Abstract

The utility model discloses a refrigerant circulation module capable of recovering expansion work and an energy storage heat management system. The refrigerant circulation module comprises an air flotation centrifugal compressor, a condenser, an ejector, a gas-liquid separator and an evaporator. The air floatation centrifugal compressor performs isentropic compression on a refrigerant, the condenser is communicated with the air floatation centrifugal compressor and performs isobaric heat release on the compressed refrigerant, the ejector comprises a receiving cavity, a mixing cavity and a diffusion cavity, the receiving cavity is provided with a liquid inlet and an air inlet which are communicated with the condenser and the evaporator respectively, and an injection module is arranged at the liquid inlet; and the refrigerant subjected to isenthalpy throttling and the refrigerant flowing in from the air inlet are mixed in the mixing cavity and pressurized in the diffusion cavity. An air inlet of the gas-liquid separator is communicated with the ejector, a liquid outlet of the gas-liquid separator is communicated with the evaporator, an exhaust port of the gas-liquid separator is communicated with the air-floating centrifugal compressor, and the evaporator absorbs heat of refrigerants at equal pressure. Partial expansion work can be recycled through the ejector, the heat exchange amount of latent heat in the compressor is increased, refrigerant filling is reduced, and the energy efficiency of the system is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of thermal management, and in particular to a refrigerant circulation module capable of recovering expansion work and an energy storage thermal management system. Background Art

[0002] Thermal management refers to the management and control of the temperature of the total system, discrete components or their environment, with the purpose of maintaining the normal operation of each component or improving its performance or life. At present, thermal management is usually required in fields such as electrochemical energy storage. Thermal management has a significant impact on the performance, life and safety of energy storage systems. Since the liquid-cooled thermal management system has a strong heat exchange capacity and the temperature difference of the battery cells can be within 3°C, it can significantly increase the life of the energy storage system compared to the air-cooled system. In view of this, liquid cooling systems are currently mostly used in the field of energy storage.

[0003] Positive displacement compressors are usually used in existing energy storage thermal management systems. However, the power density of traditional positive displacement compressors is generally low. In order to meet the refrigeration needs of energy storage thermal management, high-power compressors or even two compressor systems are often required. In addition, the efficiency of positive displacement compressors is low, which in turn leads to low efficiency of the energy storage thermal management system. At the same time, there is friction between the internal parts of the positive displacement compressor during operation. In order to avoid reducing the reliability of the system operation, compressor oil is often required to achieve lubrication and sealing. On the one hand, the compressor oil will increase the manufacturing cost and operating cost of the compressor. For example, before starting at low temperature, the compressor needs to be heated to reduce the viscosity of the compressor oil. On the other hand, after the compressor oil enters the system, it will be miscible with the refrigerant, affecting the heat exchange of the refrigerant, which directly leads to a decrease in the cooling capacity of the system.

[0004] In addition, existing energy storage thermal management systems mostly use throttling devices such as capillaries to achieve throttling expansion of the refrigerant. However, the throttling expansion process of the capillary tube or other throttling devices is an isenthalpic expansion, which has a large throttling loss, and a large pressure difference is generated after the system is throttled. The compressor consumes a lot of power, and the refrigerant after throttling is in a two-phase state in the evaporator. The latent heat is not maximized, resulting in a large amount of refrigerant filling and high cost. Utility Model Content

[0005] In view of some or all of the problems in the prior art, the utility model provides a refrigerant circulation module capable of recovering expansion work in a first aspect, comprising:

[0006] An air-floating centrifugal compressor, which is used to isentropically compress the refrigerant;

[0007] A condenser, the air inlet of which is connected to the air outlet of the air-floating centrifugal compressor, so as to release heat isobarically to the compressed refrigerant;

[0008] The ejector includes an air inlet, a liquid inlet and an exhaust port, and its internal chamber includes the following in sequence along the refrigerant flow direction:

[0009] A receiving chamber, wherein the liquid inlet and the air inlet are arranged on the receiving chamber and are respectively connected to the liquid outlet of the condenser and the air outlet of the evaporator, wherein an injection module is arranged at the liquid inlet to perform isenthalpic throttling on the refrigerant;

[0010] A mixing chamber, in which the refrigerant after isenthalpic throttling is mixed with the refrigerant flowing into the air inlet; and

[0011] A pressure diffuser chamber, which is used to pressurize the mixed refrigerant;

[0012] a gas-liquid separator, whose air inlet is connected to the exhaust port of the ejector, whose liquid outlet is connected to the liquid inlet of the evaporator, and whose exhaust port is connected to the air inlet of the air-floating centrifugal compressor; and

[0013] The evaporator is used to absorb heat from the refrigerant at isobaric pressure.

[0014] Furthermore, the injection module includes a spray needle and a nozzle.

[0015] Furthermore, the air-floating centrifugal compressor comprises:

[0016] An electric motor comprising:

[0017] A shell, wherein a first chamber and a second chamber are respectively disposed at two ends thereof;

[0018] The rotor is provided with two radial air bearings and a thrust plate.

[0019] The thrust plate is arranged at one end close to the first chamber, and an air-floating thrust bearing is arranged on both sides of the thrust plate, and the two thrust bearings are arranged opposite to each other; and a stator is fixed inside the housing, and its central axis coincides with the central axis of the rotor;

[0020] The first and second impellers are respectively disposed in the first chamber and the second chamber, and are fixed on the rotor in a back-to-back manner;

[0021] an air inlet, which is in communication with the air inlet of the first chamber;

[0022] an exhaust port communicating with the air outlet of the second chamber; and

[0023] The connecting pipe has two ends connected to the air outlet of the first chamber and the air inlet of the second chamber respectively.

[0024] Furthermore, the radial bearing and the thrust bearing are foil-type dynamic pressure air bearings.

[0025] Furthermore, a first end cover and a second end cover are respectively provided at the air outlets of the first chamber and the second chamber, and there are gaps between the first end cover, the second end cover and the rotor, between the first end cover and the first impeller, and between the second end cover and the second impeller.

[0026] Furthermore, the first and second impellers are fixed to the rotor via locking nuts.

[0027] Furthermore, a first compression shell and a second compression shell are respectively disposed at two ends of the motor.

[0028] Furthermore, a first sealing ring is provided between the first compression shell and the first impeller, and

[0029] A second sealing ring is arranged between the second compression shell and the second impeller.

[0030] Furthermore, the connecting pipe is provided with an inter-stage air supply hole to receive the exhaust gas from the economizer.

[0031] Furthermore, the motor is a high-speed permanent magnet synchronous motor.

[0032] Based on the refrigerant circulation module as described above, the second aspect of the utility model provides an energy storage thermal management system, which includes the refrigerant circulation module and the coolant circulation module as described above, wherein the coolant circulation module includes a water pump, and the water pump provides power for the coolant. The coolant flows through the module to be cooled and the evaporator to perform heat exchange and achieve heat dissipation.

[0033] The utility model provides a refrigerant circulation module and energy storage thermal management system that can recover expansion work. The ejector is used to replace the traditional throttling device to recover part of the expansion work, increase the latent heat exchange in the compressor, reduce the refrigerant filling, and at the same time increase the suction pressure of the compressor, reduce the power consumption of the compressor, and thus improve the energy efficiency of the system by at least 10%. In addition, the energy storage thermal management system uses an air-floating centrifugal compressor to replace the traditional positive displacement compressor. The air-floating centrifugal compressor uses an air-floating bearing, so no lubricating oil is required, and the return oil pipeline can be omitted, thereby improving the reliability of the compressor and the system. At the same time, since the rotating shaft of the air-floating bearing does not contact the bearing when working, but relies on the air film to suspend the motor rotor, the bearing life can also be increased by at least 1 times. In addition, under the same cooling capacity, the size and weight of the centrifugal compressor based on the high-speed permanent magnet synchronous motor will be about 50% smaller than the scroll compressor, and the mass can be reduced by about 90%, which makes it possible to arrange more batteries in the same size container when it is applied to the energy storage system, thereby helping to improve the energy density of the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] To further illustrate the above and other advantages and features of various embodiments of the present invention, a more specific description of various embodiments of the present invention will be presented with reference to the accompanying drawings. It will be understood that these drawings only depict typical embodiments of the present invention and are therefore not to be considered as limiting the scope thereof. In the accompanying drawings, for clarity, identical or corresponding components will be represented by identical or similar reference numerals.

[0035] Figure 1 A schematic structural diagram of an energy storage thermal management system capable of recovering expansion work according to an embodiment of the utility model is shown;

[0036] Figure 2 A schematic diagram showing the structure of an ejector according to an embodiment of the utility model;

[0037] Figure 3 A schematic diagram showing pressure-enthalpy change during the working process of a refrigerant circulation module capable of recovering expansion work according to an embodiment of the utility model;

[0038] Figure 4 A schematic diagram showing the structure of an air-floating centrifugal compressor according to an embodiment of the utility model; and

[0039] Figure 5 A cross-sectional schematic diagram of an air-floating centrifugal compressor according to an embodiment of the utility model is shown.

[0040] Reference numerals list

[0041] 101 Air floating centrifugal compressor 411 rotor

[0042] 102 Condenser 412 Stator

[0043] 103 ejector 413 shell

[0044] 131 liquid inlet 421 first impeller

[0045] 132 Air inlet 422 Second impeller

[0046] 133 Exhaust port 431 Inlet port

[0047] 104 Gas-liquid separator 432 exhaust port

[0048] 105 Evaporator 433 connecting pipe

[0049] 106 Water pump 434 interstage air supply hole

[0050] 211 Spray needle 441 Air bearing

[0051] 212 Nozzle 442 Thrust Plate

[0052] 221 receiving cavity 443 thrust bearing

[0053] 222 mixing chamber 451 first end cover

[0054] 223 Diffuser chamber 452 Second end cover

[0055] 453 First locking nut

[0056] 454 Second locking nut

[0057] 455 First compression shell

[0058] 456 Second compression shell

[0059] 457 First sealing ring

[0060] 458 Second sealing ring DETAILED DESCRIPTION

[0061] The present invention is further described below with reference to the accompanying drawings in conjunction with specific embodiments. It should be noted that the components in the accompanying drawings may be exaggerated for illustration purposes and are not necessarily proportionally correct. In the accompanying drawings, the same reference numerals are assigned to components that are the same or have the same function.

[0062] In the present invention, unless otherwise specified, "arranged on...", "arranged above..." and "arranged above..." do not exclude the existence of an intermediate object between the two. In addition, "arranged on or above..." only indicates the relative positional relationship between two components, and in certain circumstances, such as after reversing the product direction, it can also be converted into "arranged under or below...", and vice versa.

[0063] In the present invention, each embodiment is only intended to illustrate the solution of the present invention and should not be understood as limiting.

[0064] In the present invention, unless otherwise specified, the quantifiers "a", "an" and "an" do not exclude the presence of multiple elements.

[0065] It should also be pointed out that in the embodiments of the present invention, for the sake of clarity and simplicity, only a portion of the parts or components may be shown, but a person of ordinary skill in the art will understand that, under the guidance of the present invention, required parts or components may be added according to the needs of specific scenarios.

[0066] It should also be pointed out that within the scope of the present invention, the terms "same", "equal", "equal to" and the like do not mean that the values ​​of the two are absolutely equal, but allow a certain reasonable error, that is, the terms also cover "substantially the same", "substantially equal", "substantially equal to". By analogy, in the present invention, the terms "perpendicular to", "parallel to", etc. indicating directions also cover the meanings of "substantially perpendicular to" and "substantially parallel to".

[0067] The present invention will be further described below in conjunction with specific embodiments with reference to the accompanying drawings.

[0068] Figure 1 The following is a schematic diagram showing the structure of an energy storage thermal management system capable of recovering expansion work according to an embodiment of the present invention. Figure 1 As shown, a heat storage management system capable of recovering expansion work includes a refrigerant circulation module and a coolant circulation module, wherein the coolant is used to cool down the heat dissipation module, and the refrigerant is used to cool down the coolant through heat exchange with the coolant.

[0069] like Figure 1 As shown, the refrigerant circulation module includes an air-floating centrifugal compressor 101, a condenser 102, an ejector 103, a gas-liquid separator 104 and an evaporator 105. As shown in the figure, the air inlet of the air-floating centrifugal compressor 101 is communicated with the exhaust port of the gas-liquid separator 104, the air outlet of the air-floating centrifugal compressor 101 is communicated with the air inlet of the condenser 102, the liquid outlet of the condenser 102 is communicated with the liquid inlet 131 of the ejector 103, the air inlet 132 of the ejector 103 is communicated with the air outlet of the evaporator 105, the exhaust port 133 of the ejector 103 is communicated with the air inlet of the gas-liquid separator 104, and the liquid outlet of the gas-liquid separator 104 is communicated with the liquid inlet of the evaporator 105. The coolant circulation module includes a water pump 106, which provides power for the coolant. The coolant flows through the module to be cooled and the evaporator to perform heat exchange and achieve heat dissipation.

[0070] Based on this, the entire refrigerant cycle includes: first, the refrigerant is isentropically compressed in the air-floating centrifugal compressor 101 , the compressed refrigerant is isobarically released in the condenser 102 , and enters the ejector 103 through the liquid inlet 131 . Figure 2 The schematic diagram of the structure of the ejector of one embodiment of the utility model is shown. Figure 2 As shown, in one embodiment of the present invention, the internal chamber of the ejector includes a receiving chamber 221, a mixing chamber 222 and a pressure diffusion chamber 223 in sequence along the refrigerant flow direction, wherein the liquid inlet 131 and the air inlet 132 are arranged at the receiving chamber 221, and the exhaust port 133 is arranged at the pressure diffusion chamber 223. Figure 2 As shown, an injection module is provided at the liquid inlet 131 of the ejector 103 to perform isenthalpic throttling on the refrigerant. As shown in the figure, in one embodiment of the utility model, the injection module includes a spray needle 211 and a nozzle 212, and the condensed refrigerant enters the spray needle 211, and then is sprayed into the receiving chamber 221 of the ejector through the nozzle 212 to achieve isenthalpic throttling. At the same time, the refrigerant evaporated by the evaporator 105 enters the receiving chamber 221 from the air inlet 132 of the ejector 103 to achieve injection decompression, and is mixed with the refrigerant throttled by the injection module in the mixing chamber 222, and the refrigerant in the mixed state is further pressurized in the diffusion chamber 223 of the ejector 103, and sent to the gas-liquid separator 104. The high-pressure refrigerant discharged from the ejector 103 flashes into a saturated gas phase and a saturated liquid phase in the gas-liquid separator 104, and enters the air-floating centrifugal compressor 101 and the evaporator 105 through the exhaust port and the liquid outlet, respectively. The liquid refrigerant absorbs heat at isobaric pressure in the evaporator 105 to cool the coolant. Figure 3 A schematic diagram showing the pressure-enthalpy change during the working process of a refrigerant circulation module of an energy storage thermal management system capable of recovering expansion work according to an embodiment of the present invention is shown. Figure 3 As shown, by using an ejector instead of the traditional throttling device, the expansion work can be recovered, thereby increasing the latent heat of vaporization △h in the evaporator. When the total required heat exchange amount remains unchanged, the refrigerant flow rate is reduced, the refrigerant charge amount can be reduced, and the cost is saved. In addition, when the refrigerant flow rate in the refrigerant circulation system decreases, the power consumption of the air-floating centrifugal compressor will also be reduced.

[0071] Figure 4 and Figure 5 The structure and cross-sectional schematic diagram of an air-floating centrifugal compressor of an embodiment of the utility model are respectively shown. The air-floating centrifugal compressor adopts an air-floating bearing, and the gas in the main air path of the compressor is introduced into the bearing position through the rotation of the rotor to form an air film, thereby achieving an air-floating effect. As shown in the figure, in an embodiment of the utility model, the air-floating centrifugal compressor includes a motor, an impeller, an air inlet 431, an exhaust port 432 and a connecting pipe 433.

[0072] The motor includes a rotor 411, a stator 412 and a housing 413. The stator 412 is fixed inside the housing 413, and the central axis of the rotor 411 coincides with the central axis of the stator 412. Two radial air bearings 441 are provided on the rotor 411, and a thrust disk 442 is provided on the side close to the air inlet 431, and an air-floating thrust bearing 443 is provided on both sides of the thrust disk, respectively. The two thrust bearings are arranged opposite to each other to bear the axial thrust directed to the low-pressure side or the high-pressure side, respectively.

[0073] As shown in the figure, the first chamber and the second chamber are respectively provided at the two ends of the interior of the housing 413. The air inlet of the first chamber is connected to the air inlet 431 of the compressor, and it can also be understood that the air inlet 431 is the air inlet of the first chamber. The first chamber is provided with a first impeller 421, and the first impeller 421 is fixed to the first end of the rotor 411. A connecting pipe 433 is provided between the first chamber and the second chamber. The gas compressed by the first impeller 421 flows out from the air outlet of the first chamber and enters the connecting pipe 433, and then enters the second chamber through the air inlet of the second chamber. The second chamber is provided with a second impeller 422, and the second impeller 422 is fixed to the second end of the rotor 411. Most of the gas compressed by the second impeller 422 flows out from the air outlet of the second chamber. The air outlet of the second chamber is connected to the exhaust port 432 of the compressor, and it can also be understood that the exhaust port 432 is the air outlet of the second chamber. As shown in the figure, in an embodiment of the utility model, the first chamber and the second chamber are respectively provided with a first end cover 451 and a second end cover 452 at the air outlet, and there is a gap between the first end cover 451 and the second end cover 452 and the rotor 411. At the same time, there is a certain gap between the first end cover 451 and the first impeller 421, and the gas flowing through the air bearing can return to the main gas path through this gap. There is also a certain gap between the second end cover 452 and the second impeller 422, and a part of the gas compressed by the second impeller 422 can enter the air bearing through this gap under the action of pressure. In one embodiment of the utility model, the first impeller 421 and the second impeller 422 are both closed impellers. Compared with the open impeller, the closed impeller can effectively eliminate the secondary flow from the pressure surface of the blade to the suction surface caused by the tip clearance, thereby effectively improving the aerodynamic efficiency of the compressor. In one embodiment of the present invention, as shown above, the first impeller 421 and the second impeller 422 are designed back to back, so that the axial thrusts of the first and second impellers are in opposite directions and cancel each other out, thereby effectively reducing the axial thrusts received by the thrust bearing. In one embodiment of the present invention, the first impeller 421 and the second impeller 422 are fixed to the rotor 411 by a first locking nut 453 and a second locking nut 454, respectively.

[0074] As shown in the figure, a first compression shell 455 and a second compression shell 456 are respectively provided on the outer sides of the two ends of the motor, a first sealing ring 457 is provided between the first compression shell 455 and the first impeller 421, and a second sealing ring 458 is provided between the second compression shell 456 and the second impeller 422. The first and second sealing rings can significantly reduce the backflow effect from the outlet to the inlet of the first and second impellers, and can further improve the efficiency of the compressor.

[0075] In order to reduce the compression power consumption of the second impeller 422, in one embodiment of the present invention, an interstage air supply hole 434 is further provided on the connecting pipe 433 to receive the exhaust gas from the economizer to cool the gas compressed by the first impeller, thereby achieving the purpose of reducing the compression power consumption of the high-pressure impeller and improving the efficiency of the system.

[0076] In one embodiment of the utility model, the motor adopts a high-speed permanent magnet synchronous motor, and its bearing is a non-contact bearing when working, so it can withstand a higher speed than a conventional ball bearing. According to the Euler formula of the compressor Δh=U2Cu2-U1Cu1, it can be known that for compressors with the same functional capacity, the greater the speed, the smaller the radial size, so the use of a permanent magnet synchronous motor can improve the power density of the compressor.

[0077] Although various embodiments of the utility model are described above, it should be understood that they are presented as examples only and not as limitations. It is obvious to those skilled in the relevant art that various combinations, modifications and changes can be made thereto without departing from the spirit and scope of the utility model. Therefore, the breadth and scope of the utility model disclosed herein should not be limited by the exemplary embodiments disclosed above, but should only be defined according to the attached claims and their equivalents.

Claims

1. A refrigerant circulation module capable of recovering expansion work, characterized in that: include: an air-floating centrifugal compressor configured to isentropically compress a refrigerant; A condenser, the air inlet of which is connected to the air outlet of the air-floating centrifugal compressor, so as to release heat isobarically to the compressed refrigerant; The ejector includes an air inlet, a liquid inlet and an exhaust port, and its internal chamber includes the following in sequence along the refrigerant flow direction: A receiving chamber, wherein the liquid inlet and the air inlet are arranged on the receiving chamber and are respectively connected to the liquid outlet of the condenser and the air outlet of the evaporator, wherein an injection module is arranged at the liquid inlet to perform isenthalpic throttling on the refrigerant; A mixing chamber, in which the refrigerant after isenthalpic throttling is mixed with the refrigerant flowing into the air inlet; and a diffuser chamber configured to pressurize the mixed refrigerant; a gas-liquid separator, whose air inlet is connected to the exhaust port of the ejector, whose liquid outlet is connected to the liquid inlet of the evaporator, and whose exhaust port is connected to the air inlet of the air-floating centrifugal compressor; and The evaporator is configured to absorb heat from the refrigerant at an isobaric pressure.

2. The refrigerant circulation module according to claim 1, characterized in that: The injection module includes a spray needle and a nozzle.

3. The refrigerant circulation module according to claim 1, characterized in that: The air-floating centrifugal compressor comprises: An electric motor comprising: A shell, wherein a first chamber and a second chamber are respectively disposed at two ends thereof; A rotor, on which two radial air bearings and a thrust plate are arranged, wherein the thrust plate is arranged at one end close to the first chamber, and an air bearing is arranged on both sides of the thrust plate, and the two thrust bearings are arranged opposite to each other; and a stator, which is fixed inside the housing, and whose central axis coincides with the central axis of the rotor; A first impeller and a second impeller are respectively disposed in the first chamber and the second chamber, and are fixed on the rotor in a back-to-back manner; an air inlet, which is in communication with the air inlet of the first chamber; an exhaust port communicating with the air outlet of the second chamber; and The connecting pipe has two ends connected to the air outlet of the first chamber and the air inlet of the second chamber respectively.

4. The refrigerant circulation module according to claim 3, characterized in that: The radial bearing and the thrust bearing are foil-type dynamic pressure air bearings.

5. The refrigerant circulation module according to claim 3, characterized in that: A first end cover and a second end cover are respectively provided at the air outlets of the first chamber and the second chamber, and there are gaps between the first end cover, the second end cover and the rotor, between the first end cover and the first impeller, and between the second end cover and the second impeller.

6. The refrigerant circulation module according to claim 3, characterized in that: The two ends of the motor are respectively provided with a first compression shell and a second compression shell.

7. The refrigerant circulation module according to claim 6, characterized in that: A first sealing ring is provided between the first compression shell and the first impeller, and A second sealing ring is arranged between the second compression shell and the second impeller.

8. The refrigerant circulation module according to claim 3, characterized in that: The connecting pipe is provided with an inter-stage air supply hole to receive the exhaust gas from the economizer.

9. The refrigerant circulation module according to claim 3, characterized in that: The motor is a high-speed permanent magnet synchronous motor.

10. An energy storage thermal management system, characterized in that: include: The refrigerant circulation module according to any one of claims 1 to 9; as well as A coolant circulation module includes a water pump, and the water pump is configured to provide power for the coolant. The coolant flows through the module to be cooled and the evaporator to perform heat exchange and dissipate heat from the module to be cooled.

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