Energy storage heat management system of air flotation centrifugal compressor

Abstract

The utility model relates to an energy storage heat management system of an air-floating centrifugal compressor, which comprises a refrigerating circuit, a heat exchanger, a heat exchanger and an air-floating centrifugal compressor, and is characterized in that the refrigerating circuit is configured to circulate refrigerants; the heat exchange medium loop is configured to circulate a heat exchange medium so as to cool target equipment; one part of the heat exchange device is communicated with the refrigerating loop, and the other part of the heat exchange device is communicated with the heat exchange medium loop; the air flotation centrifugal compressor is arranged on the refrigeration loop; and an ambient temperature sensor configured to detect a temperature of an environment in which the thermal management system is located. The air flotation centrifugal compressor is adopted as a core component of the refrigerating system, and compared with a traditional electric scroll compressor, the air flotation centrifugal compressor is small in size, light in weight, free of compressor oil, high in reliability of the compressor and the system and large in refrigerating capacity of the system.

Description

TECHNICAL FIELD

[0001] The utility model relates to heat management technical field especially relates to a gas float centrifugal compressor energy storage heat management system. BACKGROUND

[0002] Heat management is the necessity of electrochemical energy storage, which has a significant impact on the performance, life and safety of energy storage system. The existing energy storage heat management system uses traditional positive displacement compressor, which has the following defects:

[0003] Traditional positive displacement compressor has low efficiency, which leads to low efficiency of energy storage heat management system. In order to meet the refrigeration demand of energy storage heat management, high-power compressor or even two sets of compressor system are needed.

[0004] The internal parts of traditional positive displacement compressor have friction during operation, which needs to be lubricated and sealed with compressor oil. This reduces the efficiency and reliability of system operation, increases the cost of compressor, and before starting at low temperature, the compressor needs to be heated to reduce the viscosity of compressor oil. After the compressor oil enters the system, it is mutually soluble with refrigerant, which affects the heat exchange of heat exchanger and directly leads to the decrease of system refrigerating capacity.

[0005] The traditional positive displacement compressor used in current energy storage heat management products cannot realize the function of air supplement and enthalpy increase, and cannot realize the further improvement of energy efficiency.

[0006] The compressor assembly has a large volume, which leads to large volume of integrated energy storage heat management unit, and further reduces the layout space of energy storage battery. UTILITY MODEL CONTENTS

[0007] In order to solve at least part of the above problems in the prior art, the utility model provides a gas float centrifugal compressor energy storage heat management system, which comprises:

[0008] A refrigeration circuit configured to circulate refrigerant;

[0009] A heat exchange medium circuit configured to circulate heat exchange medium to cool the target device;

[0010] A heat exchange device, one part of which communicates with the refrigeration circuit, and the other part communicates with the heat exchange medium circuit;

[0011] A gas float centrifugal compressor arranged on the refrigeration circuit; and

[0012] An ambient temperature sensor configured to detect the temperature of the environment where the heat management system is located.

[0013] Further, it further comprises:

[0014] a condenser in communication with the gas-bearing centrifugal compressor;

[0015] a main throttling element disposed between the condenser and the heat exchange device;

[0016] a secondary throttling element having an input end and an output end, both of which are in communication with the economizer; and

[0017] an economizer having a first input end, a first output end, a second input end, and a second output end, the first input end being in communication with the condenser, the first output end being in communication with the input end of the main throttling element and the secondary throttling element, the second input end being in communication with the output end of the secondary throttling element, and the second output end being in communication with the gas-bearing centrifugal compressor.

[0018] Further, the gas-bearing centrifugal compressor has an air inlet, an air outlet, and a makeup air inlet, wherein the air inlet is in communication with the heat exchange device, the air outlet is in communication with the condenser, and the makeup air inlet is in communication with the second output end of the economizer.

[0019] Further, the system further comprises:

[0020] a solenoid valve having an input end in communication with the heat exchange device and an output end in communication with the condenser;

[0021] a fan disposed on the condenser.

[0022] Further, the system further comprises a water pump disposed on the heat exchange medium circuit.

[0023] Further, the heat exchange device has a first fluid inlet, a first fluid outlet, a second fluid inlet, and a second fluid outlet, wherein the first fluid inlet of the heat exchange device is connected to the output end of the main throttling element, the first fluid outlet is connected to the air inlet of the gas-bearing centrifugal compressor and the input end of the solenoid valve, respectively, the second fluid outlet of the heat exchange device is connected to the input end of a target device disposed on the heat exchange medium circuit.

[0024] Further, the system further comprises:

[0025] an air outlet temperature sensor and an air outlet pressure sensor disposed at the air outlet of the gas-bearing centrifugal compressor;

[0026] a makeup air pressure sensor and a makeup air temperature sensor disposed between the second output end of the economizer and the makeup air inlet of the gas-bearing centrifugal compressor;

[0027] a main circuit pressure sensor and a main circuit temperature sensor disposed between the output end of the main throttling element and the first fluid inlet of the heat exchange device;

[0028] a suction air pressure sensor and a suction air temperature sensor disposed at the first fluid outlet of the heat exchange device.

[0029] A waterway outlet water temperature sensor and a waterway outlet water pressure sensor are arranged between the first fluid outlet of the heat exchange device and the target device.

[0030] Further, the ambient temperature sensor is arranged at an air inlet of the fan.

[0031] Further, the gas-bearing centrifugal compressor comprises:

[0032] The motor comprises:

[0033] The housing has a first chamber and a second chamber at two ends of the housing respectively, and the rotor is provided with a radial bearing, which is a gas-bearing bearing and is configured to support the rotor in the radial direction;

[0034] The impeller is arranged at an end of the rotor and located in the first chamber and / or the second chamber;

[0035] The gas inlet is in communication with the gas inlet of the first chamber;

[0036] The gas outlet is in communication with the gas outlet of the second chamber;

[0037] The connecting pipe has two ends in communication with the gas outlet of the first chamber and the gas inlet of the second chamber respectively.

[0038] Further, the centrifugal compressor further comprises a gas supplementing port arranged on the connecting pipe.

[0039] The heat management system of the utility model has at least the following beneficial effects: the heat management system of the utility model adopts the gas-bearing centrifugal compressor, the gas-bearing centrifugal compressor is small in size, under the same cooling capacity, compared with the scroll compressor, the size of the super-speed gas-bearing centrifugal compressor is reduced by about 50%, the weight is reduced by about 90%, and more energy storage batteries can be arranged in the container of the same size. The gas-bearing centrifugal compressor adopts the gas-bearing bearing, does not need oil lubrication, the rotating shaft does not contact the bearing when the gas-bearing bearing works, but relies on the gas film to suspend the motor rotor, can improve the system operation life by more than 1 times, and improves the reliability of the energy storage system. The gas-bearing centrifugal compressor saves the oil return pipeline and electric heating, reduces the structure and the cost of the compressor. The gas-bearing centrifugal compressor adopts the gas-bearing bearing, does not use the compressor oil, improves the heat exchange efficiency of the heat exchange device, and improves the system refrigerating capacity. The two-stage compression gas-bearing centrifugal compressor adopts the intermediate gas supplementing mode, improves the system supercooling degree, reduces the power consumption of the compressor, and further improves the overall energy efficiency of the energy storage heat management system. BRIEF DESCRIPTION OF DRAWINGS

[0040] To further clarify the above and other advantages and features of the embodiments of the present application, a more particular description of embodiments of the application will be rendered by reference to specific drawings. It is appreciated that these drawings are only illustrative and are, therefore, not to be considered as limiting the scope of the application. In the drawings, like or similar elements are denoted by the same or similar reference signs.

[0041] Figure 1 A schematic diagram of an air-float centrifugal compressor energy storage thermal management system in an embodiment of the present application is shown.

[0042] Figure 2 A schematic diagram of a wind volume size control strategy in an embodiment of the present application is shown.

[0043] Figure 3 A flow chart of a fan control method in an embodiment of the present application is shown.

[0044] Figures 4-6 A structural schematic diagram of an air-float centrifugal compressor in an embodiment of the present application is shown.

[0045] Reference signs: air-float centrifugal compressor 1, exhaust temperature sensor 2, exhaust pressure sensor 3, electromagnetic valve 4, condenser 5, ambient temperature sensor 6, fan 7, makeup gas pressure sensor 8, makeup gas temperature sensor 9, economizer 10, auxiliary throttling element 11, main throttling element 12, main circuit pressure sensor 13, main circuit temperature sensor 14, evaporator 15, suction pressure sensor 16, suction temperature sensor 17, water pump 18, water circuit outlet water temperature sensor 19, water circuit outlet water pressure sensor 20, battery pack heat source 21, motor 100, air inlet 301, air outlet 302, connecting pipe 303, rotor 101, stator 102, shell 103, air-float bearing 111, thrust disc 112, thrust bearing 113, first impeller 201, second impeller 202, first end cover 135, second end cover 136, first compression shell 131, second compression shell 132, first sealing ring 133, second sealing ring 134, makeup gas inlet 331, first locking nut 211, second locking nut 221. DETAILED DESCRIPTION

[0046] It should be noted that the components in the various figures can be exaggerated for the purpose of illustration and are thus not necessarily drawn to scale.

[0047] In the present application, each embodiment is merely intended to illustrate the scheme of the present application and should not be understood as limiting.

[0048] In the present application, unless specifically indicated, the quantifier "one" does not exclude the scenario of multiple elements.

[0049] It should be noted here that, in the embodiments of the present application, only a part of components or assemblies may be shown for the sake of clarity and simplicity, but those skilled in the art can understand that, under the guidance of the present application, the required components or assemblies can be added according to the specific scene needs.

[0050] It should be noted here that, within the scope of the present application, the words "same", "equal", "equal to" and the like do not mean that the two values are absolutely equal, but allow a certain reasonable error, that is, the words also cover "basically the same", "basically equal", "basically equal".

[0051] It should be noted here that, in the description of the present application, the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not mean that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as explicitly or implicitly indicating relative importance.

[0052] In addition, the embodiments of the present application describe the process steps in a specific order, however this is only for the convenience of distinguishing each step and is not limited to the order of the steps, in different embodiments of the present application, the order of the steps can be adjusted according to the adjustment of the process.

[0053] In view of the shortcomings of the existing energy storage thermal management products, the present application takes a high-speed air-floating centrifugal compressor as the power source of the refrigerant circuit, designs a set of high-efficiency energy storage thermal management system, and combines with a unique control strategy to realize an optimal energy storage thermal management scheme.

[0054] Figure 1 A schematic diagram of an air-floating centrifugal compressor energy storage thermal management system in an embodiment of the present application is shown.

[0055] As Figure 1As shown, a gas floating centrifugal compressor energy storage thermal management system includes: a refrigeration circuit configured to circulate refrigerant; a heat exchange medium circuit configured to circulate heat exchange medium to cool a target device; a refrigeration system component provided on the refrigeration circuit. A heat exchange device, one part of the heat exchange device is in communication with the refrigeration circuit, and the other part is in communication with the heat exchange medium circuit. The heat exchange device is configured to transfer heat between the refrigeration circuit and the heat exchange medium circuit. The heat exchange device may, for example, be an evaporator 15. The evaporator 15 has a first fluid inlet, a first fluid outlet, a second fluid inlet, and a second fluid outlet. The target device is provided on the heat exchange medium circuit, and the target device is a battery pack heat source 21.

[0056] The refrigeration system component includes a gas floating centrifugal compressor 1, a solenoid valve 4, a condenser 5, a fan 7, a main throttling element 12, an auxiliary throttling element 11, and an economizer 10. The throttling elements include electronic expansion valves, thermal expansion valves, capillary tubes, etc. The fan 7 is provided on the condenser 5, and the fan 7 is used to ventilate and exchange heat for high-temperature and high-pressure refrigerant, and to carry heat to the air. The solenoid valve 4 has two ends connected between the gas floating centrifugal compressor 1 inlet and the evaporator 15 first fluid outlet, and the gas floating centrifugal compressor 1 exhaust port and the condenser 5. The input end of the solenoid valve 4 is in communication with the evaporator 15, and the output end is in communication with the condenser 5.

[0057] The components of the refrigeration system component are connected by pipes (copper pipes), and the pipe diameter is matched according to the system flow, design pressure, and design temperature.

[0058] The refrigeration system component further includes: an exhaust temperature sensor 2, an exhaust pressure sensor 3, an ambient temperature sensor 6, a charge pressure sensor 8, a charge temperature sensor 9, a main line pressure sensor 13, a main line temperature sensor 14, a suction pressure sensor 16, and a suction temperature sensor 17.

[0059] The exhaust temperature sensor 2 and the exhaust pressure sensor 3 are provided at the exhaust port of the gas floating centrifugal compressor 1.

[0060] The charge pressure sensor 8 and the charge temperature sensor 9 are provided between the second output end of the economizer 10 and the charge port of the gas floating centrifugal compressor 1.

[0061] The main line pressure sensor 13 and the main line temperature sensor 14 are provided between the output end of the main throttling element 12 and the first fluid inlet of the evaporator 15.

[0062] The suction pressure sensor 16 and the suction temperature sensor 17 are provided at the first fluid outlet of the evaporator 15.

[0063] The ambient temperature sensor 6 is provided at the air inlet of the fan 7, and the ambient temperature sensor 6 is used to detect the temperature of the environment in which the thermal management system is located.

[0064] The heat management system further comprises a cooling liquid system assembly, which is arranged in the heat exchange medium circuit and comprises a water pump 18, a water outlet temperature sensor 19, and a water outlet pressure sensor 20.

[0065] The water outlet temperature sensor 19 and the water outlet pressure sensor 20 are arranged between the second fluid outlet of the evaporator 15 and the input end of the battery pack heat source 21.

[0066] In the refrigeration circuit, the first fluid outlet of the evaporator 15 is connected to the air inlet of the air floating centrifugal compressor 1 and the input end of the electromagnetic valve 4, respectively; the air outlet of the air floating centrifugal compressor 1 is connected to the input end of the condenser 5, and the output end of the electromagnetic valve 4 is connected to the input end of the condenser 5; the output end of the condenser 5 is connected to the first input end of the economizer 10, the first output end of the economizer 10 is connected to the input end of the main throttling element 12, and the output end of the main throttling element 12 is connected to the first fluid inlet of the evaporator 15; the first output end of the economizer 10 is also connected to the input end of the auxiliary throttling element 11, the output end of the auxiliary throttling element 11 is connected to the second input end of the economizer 10, and the second output end of the economizer 10 is connected to the air supplementing port of the air floating centrifugal compressor 1; the second fluid outlet of the evaporator 15 is connected to the input end of the battery pack heat source 21, the output end of the battery pack heat source 21 is connected to the input end of the water pump 18, and the output end of the water pump 18 is connected to the second input end of the evaporator 15. The fan 7 is arranged on the condenser 5.

[0067] The air floating centrifugal compressor 1 serves as the power source of the refrigerant in the system, and compresses the refrigerant in a centrifugal manner. The high-temperature refrigerant after compression reaches the condenser 5 through the pipeline, the fan 7 sucks the air at normal temperature into the condenser fins, the condenser 5 exchanges heat between the high-temperature refrigerant inside and the air, and the condensed refrigerant reaches the main throttling element 12 and the auxiliary throttling element 11 through the pipeline, the main throttling element 12 and the auxiliary throttling element 11 throttle the refrigerant, the refrigerant after throttling through the main throttling element 12 rapidly expands and enters the evaporator 15, in the evaporator 15, the throttled refrigerant absorbs heat from the heat exchange medium through the evaporator 15, so that the heat exchange medium is lowered to the expected temperature, and the evaporated refrigerant continues to reach the filter element through the pipeline, the filter element filters the impurities in the system, and the filtered refrigerant returns to the compressor again. Pressure and temperature sensors are arranged on the outlet pipeline of the compressor and the outlet pipeline of the evaporator 15, and the purpose of the sensors is to calculate the system refrigeration demand and protect the system operation.

[0068] When the unit is working, the refrigerant is discharged from the gas-float centrifugal compressor 1 in the form of high-temperature and high-pressure gas, is condensed into high-temperature and high-pressure liquid through the condenser 5, is changed into low-temperature and low-pressure liquid through the main throttling element 12, is changed into low-temperature and low-pressure gas through the evaporator 15 and is returned to the gas-float centrifugal compressor 1. In the supplementary gas circuit, the refrigerant is changed into low-temperature and low-pressure liquid through the auxiliary throttling element 11, is changed into low-temperature and low-pressure gas through the economizer 10 evaporating side and is discharged into the gas-float centrifugal compressor 1 supplementary gas inlet. The electromagnetic valve 4 is directly connected with the inlet and the exhaust side of the gas-float centrifugal compressor 1.

[0069] In the heat exchange medium circuit, the outlet of the water pump 18 is connected with the second fluid inlet of the evaporator 15, the second fluid outlet of the evaporator 15 is connected with the input end of the battery pack heat source 21, and the output end of the battery pack heat source is connected with the input end of the water pump. In the cooling liquid circulation, the water pump 18 is the power source of the cooling liquid circulation, the water pump is connected with the evaporator 15 through the water pipe, the cooling liquid is sent into the evaporator 15 (in order to improve the heat exchange efficiency, in the evaporator 15, the cooling liquid inflow direction and the refrigerant inflow direction are exactly opposite), the heat is transferred to the refrigerant, then the cooling liquid enters the energy storage battery through the pipeline, the heat generated by the battery cell is transferred to the cooling liquid again, and the cooling liquid returns to the water pump 18 again.

[0070] The energy storage heat management system comprises two parts of a refrigeration circuit and a heat exchange medium circuit, the two circuits exchange energy through the plate heat exchanger (the evaporator 15), so that the purpose of cooling the cooling liquid is achieved. The design of the refrigeration circuit and the refrigeration system components is based on the characteristics of the small cold capacity gas-float centrifugal compressor, the economizer is matched to supply gas to the compressor, the supercooling degree of the system is improved, the power consumption of the compressor is reduced, and then the overall energy efficiency is improved. At the same time, considering that the high-speed centrifugal compressor has a surge phenomenon, the electromagnetic valve is added to bypass the compressor inlet and exhaust, so that the purpose of preventing the compressor from surging is achieved.

[0071] Figures 4 to 6 The structure schematic diagram of a gas-float centrifugal compressor of one embodiment of the utility model is shown respectively. As shown in the figure, a gas-float centrifugal compressor, comprising motor 100, impeller (201, 202), air inlet 301, exhaust port 302 and connecting pipe 303.

[0072] The motor 100 comprises rotor 101, stator 102 and shell 103. The stator 102 is fixed inside the shell 103, and the central shaft of the rotor 101 coincides with the central shaft of the stator 102. Two radial gas-float bearings 111 are arranged on the rotor 101, a thrust disc 112 is arranged on the side close to the air inlet 301, and a gas-float thrust bearing 113 is arranged on the two sides of the thrust disc respectively, and the two thrust bearings are oppositely arranged to bear the axial thrust directed to the low-pressure side or the high-pressure side.

[0073] As shown in the figure, the two ends of the inside of the shell 103 are respectively provided with a first chamber and a second chamber. Among them, the air inlet of the first chamber communicates with the air inlet 301 of the compressor, and the air inlet 301 can also be understood as the air inlet of the first chamber. The first chamber is provided with a first impeller 201, and the first impeller 201 is fixed to the first end of the rotor 101. The first chamber and the second chamber are provided with a connecting pipe 303, and the gas compressed by the first impeller 201 flows out from the air outlet of the first chamber into the connecting pipe 303, and then enters the second chamber through the air inlet of the second chamber. The second chamber is provided with a second impeller 202, and the second impeller 202 is fixed to the second end of the rotor 101. Most of the gas compressed by the second impeller 202 flows out from the air outlet of the second chamber, and the air outlet of the second chamber communicates with the exhaust port 302 of the compressor, and the exhaust port 302 can also be understood as the air outlet of the second chamber. As shown in the figure, in the embodiment of the utility model, the air outlets of the first chamber and the second chamber are also respectively provided with a first end cover 135 and a second end cover 136, and there is a gap between the first end cover 135, the second end cover 136 and the rotor 101. At the same time, there is a certain gap between the first end cover 135 and the first impeller 201, and the gas flowing through the gas bearing can return to the main gas path through this gap. There is also a certain gap between the second end cover 136 and the second impeller 202, and part of the gas compressed by the second impeller 202 can enter the gas bearing through this gap under the action of pressure. In an embodiment of the utility model, the first impeller 201 and the second impeller 202 both adopt closed impellers. Compared with open impellers, closed impellers can effectively eliminate the secondary flow caused by the tip clearance of the blades, thereby effectively improving the aerodynamic efficiency of the compressor. In an embodiment of the utility model, as shown, the first impeller 201 and the second impeller 202 adopt a back-to-back design, so that the axial thrust directions of the first and second impellers are opposite and offset each other, thereby effectively reducing the axial thrust on the thrust bearing. In an embodiment of the utility model, the first impeller 201 and the second impeller 202 are fixed to the rotor 101 through a first locking nut 211 and a second locking nut 221 respectively.

[0074] As shown in the figure, the outer side of the two ends of the motor is also respectively provided with a first shell pressing 131 and a second shell pressing 132. The first shell pressing 131 and the first impeller 201 are provided with a first sealing ring 133, and the second shell pressing 132 and the second impeller 202 are provided with a second sealing ring 134. 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 202, in an embodiment of the present application, a gas supplement port 331 is further arranged on the connecting pipe 303 to access 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 an embodiment of the present application, the motor 100 adopts a high-speed permanent magnet synchronous motor, and its bearing is a non-contact bearing when working, so it can withstand a higher rotating speed than a common ball bearing. According to the compressor Euler formula Δh=U2Cu2-U1Cu1, for a compressor with the same function, the greater the rotating speed, the smaller the radial dimension, so the adoption of the permanent magnet synchronous motor can improve the power density of the compressor.

[0077] The working principle of the gas-bearing centrifugal compressor as described above is that: the gas compressed by the second impeller enters the second radial bearing on the high-pressure side through the gap between the second impeller and the second end cover and the gap between the second end cover and the rotor, then enters the first radial bearing on the low-pressure side through the air gap between the stator and the rotor, then sequentially passes through the two thrust bearings through the gap between the thrust disc and the motor housing and the gap between the thrust disc and the first end cover, and finally sequentially passes through the gap between the first end cover and the rotor and the gap between the first impeller and the first end cover to enter the first chamber, i.e., the exhaust port of the first impeller, to return to the main gas path to realize internal circulation. Compared with the static pressure gas-bearing bearing, the gas-bearing centrifugal compressor can omit the external gas supplement channel, simplify the system structure, and improve the reliability. In an embodiment of the present application, the term "main gas path" refers to the gas flow path in which the gas enters the compressor through the gas inlet, is compressed, and is then discharged through the gas outlet. The term "high-pressure side" refers to the side with a relatively high internal pressure of the compressor, and the term "low-pressure side" refers to the side relative to the high-pressure side of the compressor. Under normal circumstances, the gas flows from the high-pressure side to the low-pressure side through the gas-bearing bearing and then returns to the main gas path.

[0078] The gas-bearing centrifugal compressor has a small volume, and under the same cooling capacity, the volume of the super-speed gas-bearing centrifugal compressor is reduced by about 50% and the weight is reduced by about 90% compared with the scroll compressor. More energy storage batteries can be arranged in a container of the same size.

[0079] The gas-bearing centrifugal compressor adopts the gas-bearing bearing and does not need oil lubrication. When the gas-bearing bearing works, the rotating shaft does not contact the bearing, but relies on the gas film to suspend the motor rotor, which can improve the system operation life by more than 1 times and improve the reliability of the energy storage system.

[0080] The gas-bearing centrifugal compressor eliminates the oil return pipeline and electric heating, thereby reducing the structure and the cost of the compressor.

[0081] The gas floating centrifugal compressor adopts a gas floating bearing, does not use compressor oil, improves heat exchange efficiency of the heat exchanger, and thus improves system refrigerating capacity.

[0082] The two-stage gas floating centrifugal compressor adopts an intermediate air supplementing mode, improves system supercooling degree, reduces compressor power consumption, and thus improves overall energy efficiency of the energy storage thermal management system.

[0083] The thermal management system adopts the gas floating centrifugal compressor as a core component of the refrigeration system, is small in size, light in weight, free of compressor oil, high in reliability of the compressor and the system, and large in system refrigerating capacity, as compared with a traditional electric scroll compressor.

[0084] Figure 2 A schematic diagram of a wind volume size control strategy in an embodiment of the utility model is shown. Figure 3 A flow chart of a fan control method in an embodiment of the utility model is shown.

[0085] A fan rotating speed control method of a gas floating centrifugal compressor energy storage thermal management system, comprising:

[0086] Step 1, defining a surge state judgment condition of the gas floating centrifugal compressor.

[0087] Step 2, determining an operating state of the gas floating centrifugal compressor. The operating state of the gas floating centrifugal compressor is divided into three cases: being in a compressor normal working zone, being in a surge protection zone, and being in a surge zone, wherein the surge protection zone refers to that the compressor has not yet occurred surge but is about to occur surge.

[0088] Step 3, adopting a corresponding fan control strategy to control the rotating speed of the fan according to the operating state of the gas floating centrifugal compressor.

[0089] The fan control strategy comprises a wind volume size control strategy and a surge protection control strategy, wherein the wind volume size control strategy is to control the rotating speed of the fan in a normal operation process of the unit; the surge protection control strategy refers to that, after the gas floating centrifugal compressor is about to surge or triggers surge, the rotating speed of the cooling fan is controlled to make the gas floating centrifugal compressor avoid or escape from surge. The surge protection control strategy is to appropriately increase the rotating speed of the cooling fan when the compressor is about to surge or has already surged, so as to reduce the outlet pressure of the compressor, thereby achieving the effect of avoiding compressor surge, and the cooling fan is controlled according to the wind volume size control strategy after the compressor escapes from surge.

[0090] The fan rotating speed control method is specifically introduced below.

[0091] One or more of the compressor exhaust pressure fluctuation, pressure ratio, and compressor power fluctuation rate are selected as the operating state judgment condition of the gas floating centrifugal compressor.

[0092] 1. Compressor discharge pressure fluctuation. Discharge pressure fluctuation is the rate of change of discharge pressure per unit time. When the gas-bearing centrifugal compressor is running in stable condition, the change of discharge pressure is not big, and the variation range is very small. When it is close to or enters the surge condition, the discharge pressure will appear periodic large amplitude fluctuation.

[0093] When the compressor discharge pressure fluctuation Rp exceeds the surge discharge pressure fluctuation Rp_max, it can be judged that the gas-bearing centrifugal compressor has surged.

[0094] The critical discharge pressure fluctuation Rp_max*A1 of the surge protection zone, A1 is the surge protection coefficient of discharge pressure fluctuation. When Rp_max*A1≤Rp≤Rp_max, the gas-bearing centrifugal compressor is in the surge protection zone. When Rp<Rp_max*A1, the gas-bearing centrifugal compressor is in the normal working zone.

[0095] The protection coefficient A1 is obtained based on the test data of the compressor, which is directly related to the compressor. Different compressors have different A1 values.

[0096] 2. Pressure ratio (discharge pressure ÷ suction pressure). According to the current speed of the gas-bearing centrifugal compressor, the opening degree of the main valve, the speed of the fan and the suction and discharge temperature, the surge pressure ratio Pr_max can be calculated. The surge pressure ratio is the surge line, and the required parameters are the speed of the compressor, the suction and discharge pressure (i.e. pressure ratio).

[0097] The actual pressure ratio Pr can be calculated according to the inlet and outlet saturation pressures of the compressor. The actual pressure ratio Pr is the absolute value of the discharge pressure divided by the absolute value of the suction pressure. When the actual pressure ratio Pr exceeds the surge pressure ratio Pr_max, Pr>Pr_max, it is judged that the gas-bearing centrifugal compressor has surged. When Pr_max*B1≤Pr≤Pr_max (B1 is the surge protection coefficient of pressure ratio, and Pr_max*B1 is the critical pressure ratio of the surge protection zone), the gas-bearing centrifugal compressor is in the surge protection zone. When Pr<Pr_max*B1, the gas-bearing centrifugal compressor is in the normal working zone.

[0098] The protection coefficient B1 is obtained based on the test data of the compressor, which is directly related to the compressor. Different compressors have different B1 values.

[0099] 3. Compressor power (or current) fluctuation rate. The compressor power fluctuation rate R=(highest power-lowest power) / average power.

[0100] The surge power fluctuation rate is R_max, when the compressor power fluctuation rate R > R_max, the gas-bearing centrifugal compressor has surged. The compressor power (or current) can be detected, generally detected inside the compressor controller, sent to the controller through CAN, RS485 and other communications, and the controller calculates the fluctuation according to the power (current). Fluctuation = 2*(max-min) / (max+min), max and min are within the defined time, related to the detection period.

[0101] When R_max*C1≤R≤R_max (C1 is the surge protection coefficient of power fluctuation, R_max*C1 is the critical power fluctuation rate of surge protection zone), the gas-bearing centrifugal compressor enters the surge protection zone. When R < R_max*C1, the gas-bearing centrifugal compressor is in the normal working zone.

[0102] The protection coefficient C1 is obtained based on the test data of the compressor, and is directly related to the compressor. Different compressors have different C1 values.

[0103] The above three conditions can be used as separate determination conditions, or two or three of the compressor exhaust pressure fluctuation, pressure ratio, and compressor power (or current) fluctuation rate can be combined as the determination condition of surge, according to the complexity of the system operation environment. If the system operation environment is more complex, the judgment condition of surge should be more.

[0104] As shown in Figure 3 , in the normal working zone of the compressor, the cooling fan speed is controlled according to the air volume size control strategy.

[0105] The air volume size control strategy is based on the refrigeration capacity and energy efficiency of the thermal management unit, according to the corresponding relationship between the compressor speed, the ambient temperature, the suction pressure of the compressor, the exhaust pressure of the compressor, the exhaust temperature, the supercooling degree at the outlet of the condenser and the fan speed, to control the cooling fan speed, as shown in Figure 2 The corresponding relationship meets the following conditions:

[0106] 1. The unit is normally running, and the refrigeration capacity meets the nominal rated refrigeration capacity of the unit;

[0107] 2. The unit energy efficiency (refrigeration capacity ÷ unit operating power) is the highest;

[0108] 3. The compressor has no risk of surge.

[0109] Fan rotation speed = f (compressor rotation speed, ambient temperature, suction and discharge pressure, discharge temperature, condenser outlet supercooling degree). The general characteristics are: the compressor rotation speed is high, the ambient temperature is high, the discharge pressure is high, the discharge temperature is high, and the fan rotation speed is high; the suction pressure and the discharge pressure calculate the pressure ratio, the pressure ratio is high, and the fan rotation speed is high. In the normal working area, the compressor rotation speed, the ambient temperature, the suction and discharge pressure, the discharge temperature and the condenser outlet supercooling degree are increased, and the rotation speed of the fan is increased. The above corresponding relationship refers to the general relationship after the change of a single variable under the condition that the remaining conditions do not change.

[0110] In the surge protection area and the surge area, the setting of the cooling fan rotation speed is based on the system pressure ratio (the pressure ratio of the compressor), the discharge temperature, the compressor power fluctuation, and is as follows.

[0111] In the surge protection area, the cooling fan rotation speed is increased to reduce the discharge pressure of the air floating centrifugal compressor, so that the air floating centrifugal compressor is away from the surge area. In the surge protection area, the rotation speed of the fan is adjusted according to the basic rotation speed multiplied by the first coefficient. The basic rotation speed refers to the rotation speed of the fan when entering the surge protection area. The first coefficient may be 1-2, for example.

[0112] In the compressor surge area, the cooling fan rotation speed is increased again to make the air floating centrifugal compressor out of the surge area. After the surge occurs, the rotation speed of the fan is adjusted according to the basic rotation speed multiplied by the second coefficient, and the air floating centrifugal compressor runs in the surge area for a very short time, and the rotation speed of the fan is not increased according to the surge degree. As long as it enters the surge, the rotation speed of the fan is increased according to the coefficient. The second coefficient may be 1-2, for example, wherein the second coefficient is greater than the first coefficient.

[0113] When the duration of the compressor entering the surge area reaches the maximum surge time T, it is indicated that the increase of the rotation speed of the fan cannot make the compressor out of the surge area, and then the compressor is closed and the water chiller exits refrigeration.

[0114] The fan and the condenser are heat dissipation components of the air conditioner, which affect the discharge of the compressor. The better the heat dissipation effect is, the lower the discharge pressure of the compressor is, and the rotation speed of the fan is increased to be away from and out of the surge area.

[0115] The fan control method of the utility model is aimed at the energy storage thermal management system of the air floating centrifugal compressor, matches the control strategy of the cooling fan with the system energy efficiency, can ensure that the system runs at the best energy efficiency under all working conditions; the surge is the inherent characteristic of the centrifugal compressor, when the compressor surges, the rotation speed of the cooling fan is appropriately increased, the cooling system can be out of the surge area, and the compressor can be protected.

[0116] Although some embodiments of the present application have been described in the present application, those skilled in the art can understand that these embodiments are only shown as examples. Those skilled in the art can think of many variations, alternatives and improvements under the teaching of the present application without exceeding the scope of the present application. The appended claims are intended to limit the scope of the present application, and thereby encompass the methods and structures within the scope of these claims themselves and their equivalent transformations.

Claims

1. An air-float centrifugal compressor energy storage thermal management system, characterized in that, The heat management system comprises: a refrigeration circuit configured to circulate a refrigerant; a heat exchange medium circuit configured to circulate a heat exchange medium to cool a target device; a heat exchange device, one part of which is in communication with the refrigeration circuit and the other part of which is in communication with the heat exchange medium circuit; a gas-bearing centrifugal compressor arranged on the refrigeration circuit; an ambient temperature sensor configured to detect the temperature of the environment in which the heat management system is located; a condenser in communication with the gas-bearing centrifugal compressor; a main throttling element arranged between the condenser and the heat exchange device; a secondary throttling element, the input end and the output end of which are both in communication with the economizer; and an economizer having a first input end, a first output end, a second input end and a second output end, the first input end being in communication with the condenser, the first output end being in communication with the main throttling element and the input end of the secondary throttling element, the second input end being in communication with the output end of the secondary throttling element, and the second output end being in communication with the gas-bearing centrifugal compressor.

2. The gas-bearing centrifugal compressor energy storage thermal management system of claim 1, wherein, The gas-bearing centrifugal compressor has an air inlet, an air outlet and a makeup air inlet, wherein the air inlet is in communication with the heat exchange device, the air outlet is in communication with the condenser, and the makeup air inlet is in communication with the second output end of the economizer.

3. The gas-bearing centrifugal compressor energy storage thermal management system of claim 2, wherein, Further comprising: a solenoid valve, the input end of which is in communication with the heat exchange device, and the output end of which is in communication with the condenser; a fan arranged on the condenser.

4. The gas-bearing centrifugal compressor energy storage thermal management system of claim 3, wherein, Further comprising a water pump arranged on the heat exchange medium circuit.

5. The gas-bearing centrifugal compressor energy storage thermal management system of claim 4, wherein, The heat exchange device has a first fluid inlet, a first fluid outlet, a second fluid inlet and a second fluid outlet, wherein the first fluid inlet of the heat exchange device is connected to the output end of the main throttling element, the first fluid outlet is respectively connected to the air inlet of the gas-bearing centrifugal compressor and the input end of the solenoid valve, the second fluid outlet of the heat exchange device is connected to the input end of the target device, and the target device is arranged on the heat exchange medium circuit.

6. The gas-bearing centrifugal compressor energy storage thermal management system of claim 5, wherein, Further comprising: an exhaust gas temperature sensor and an exhaust gas pressure sensor arranged at the air outlet of the gas-bearing centrifugal compressor; a makeup air pressure sensor and a makeup air temperature sensor arranged between the second output end of the economizer and the makeup air inlet of the gas-bearing centrifugal compressor; a main line pressure sensor and a main line temperature sensor arranged between the output end of the main throttling element and the first fluid inlet of the heat exchange device; a suction pressure sensor and a suction temperature sensor arranged at the first fluid outlet of the heat exchange device; a water outlet temperature sensor and a water outlet pressure sensor arranged between the first fluid outlet of the heat exchange device and the target device.

7. The gas-bearing centrifugal compressor energy storage thermal management system of claim 3, wherein, The ambient temperature sensor is arranged at the air inlet of the fan.

8. The gas-bearing centrifugal compressor energy storage thermal management system of claim 1, wherein, The gas-bearing centrifugal compressor comprises: a motor comprising: a housing, both ends of the inside of which are respectively provided with a first chamber and a second chamber; and a rotor, a radial bearing being arranged on the rotor, the radial bearing being a gas-bearing bearing and being configured to support the rotor in the radial direction; an impeller arranged at the end of the rotor and located in the first chamber and / or the second chamber; an air inlet in communication with the air inlet of the first chamber; an air outlet in communication with the air outlet of the second chamber; a connecting pipe, both ends of which are respectively in communication with the air outlet of the first chamber and the air inlet of the second chamber.

9. The gas-bearing centrifugal compressor energy storage thermal management system of claim 8, wherein, The centrifugal compressor further comprises a supplementary air inlet, which is arranged on the connecting pipe.

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