System and method for detecting and correcting refrigeration in an ejector

Abstract

The invention relates to a system and method for detecting and correcting reverse flow in an ejector refrigeration circuit. Specifically, the invention provides a method. A system for detecting and correcting counterflow in an ejector refrigeration circuit includes ejectors, a first sensor for measuring an ejector intake superheat degree of refrigerant at a secondary low pressure input port of each of the ejectors, and a second sensor for measuring an ejector intake superheat degree of refrigerant at a secondary low pressure input port of each of the ejectors. And a second sensor for measuring the degree of superheat of the refrigerant upstream with respect to the secondary low pressure input port. The controller receives ejector suction superheat degrees and refrigerant superheat degrees and determines whether a superheat degree difference between each of the ejector suction superheat degrees and the refrigerant superheat degree falls below a threshold superheat degree difference. The controller identifies the first injector as an injector affected by counterflow based on the determined degree of superheat difference. The controller compares the opening percentages of the injectors to determine the second injector having the maximum opening percentage, and controls the first injector and the second injector to increase the refrigerant flow rate of the first injector.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 511,308, filed on June 30, 2023, which is incorporated herein by reference in its entirety. Technical Field

[0002] The present disclosure relates generally to ejector refrigeration circuits. More particularly, the present disclosure relates to a system for detecting and correcting reverse flow in an ejector refrigeration circuit. Background Art

[0003] Ejectors are sometimes used to improve the overall efficiency of commercial refrigeration systems. Ejectors improve efficiency in refrigeration systems by utilizing high pressure to help compress low pressure gas, instead of relying solely on a compressor.

[0004] Typically, the ejector may be located between the outlet of the condenser and the inlet of the receiver tank. The ejector includes a primary high-pressure inlet, a secondary low-pressure inlet, and an outlet. When the ejector is used as part of a refrigeration system, the cooling refrigerant from the heat exchanger enters each of the ejectors at the high-pressure inlet and expands to a lower pressure at the outlet of each of the ejectors. At the outlet of the ejector, the refrigerant flow will generally be both a liquid phase and a gas phase. The gas phase will be fed back to the compressor, while the liquid phase is fed through another expansion valve and then the evaporator. The fluid leaving the evaporator then flows to the low-pressure inlet of the ejector. Since the compressor can operate at a lower pressure difference and use less energy (this is because the ejector has partially compressed the refrigerant vapor to an intermediate pressure level), including an ejector reduces the load on the compressor.

[0005] However, when the ejector is operating, if the high pressure fluid and outlet fluid flow back to the secondary low pressure inlet, a large loss of compressor efficiency will result.Therefore, a reverse flow detection system is desired to help detect the return or reverse flow of refrigerant in the ejector. Summary of the invention

[0006] This summary is provided to introduce a selection of concepts in a simplified form that will be further described in the detailed description of the disclosure. This summary is neither intended to identify the key or fundamental inventive concepts of the disclosure nor to determine the scope of the disclosure.

[0007] A system for detecting and correcting backflow in an ejector refrigeration circuit is disclosed. The system includes a plurality of ejectors, a plurality of first sensors, at least one second sensor, and a controller. Each of the plurality of ejectors includes a primary high pressure input port, a secondary low pressure input port, and an output port. Each of the plurality of first sensors is adapted to measure an ejector suction superheat of refrigerant at a secondary low pressure input port of a corresponding ejector from the plurality of ejectors. At least one second sensor is located along a refrigeration evaporator flow path between at least one refrigerant evaporator and the secondary low pressure input port. At least one second sensor is adapted to measure the superheat of the refrigerant upstream relative to the secondary low pressure input port. The controller is adapted to receive the ejector suction superheat measured by the plurality of first sensors and the refrigerant superheat measured by the at least one second sensor. The controller determines whether a superheat difference between each of the ejector suction superheats and the refrigerant superheat falls below a threshold superheat difference. Then, the controller identifies a first ejector from the plurality of ejectors as an ejector affected by backflow based on the determined superheat difference. Next, the controller determines a second ejector from the plurality of ejectors by comparing the opening percentages of the plurality of ejectors so that the second ejector includes a maximum opening percentage. The controller increases the opening percentage of the first ejector and decreases the opening percentage of the second ejector to increase the refrigerant flow rate of the first ejector.

[0008] In one or more embodiments according to the present disclosure, identifying the injector affected by the reverse flow includes at least one of the following in order of priority: a) the controller identifies a first injector from the plurality of injectors as an injector affected by reverse flow if only the determined superheat difference of the first injector falls below a threshold superheat difference; b) if the determined superheat difference of more than one injector from the plurality of injectors falls below a threshold superheat difference, the controller identifies an injector from the plurality of injectors having a negative estimated suction flow as an injector affected by reverse flow; c) If the estimated intake flow of none or more than one injector from the plurality of injectors falls below zero, the controller identifies a third injector having a smallest opening percentage as the injector affected by the reverse flow.

[0009] In one or more embodiments according to the present disclosure, if the determined superheat difference of more than one ejector from the plurality of ejectors falls below a threshold superheat difference, the controller is adapted to determine a third ejector and a second ejector from the plurality of ejectors by comparing the opening percentages of the more than one ejector having a superheat difference below the threshold superheat difference, so that the third ejector includes a minimum opening percentage and the second ejector includes a maximum opening percentage. The controller identifies the third ejector from the plurality of ejectors having the minimum opening percentage as an ejector affected by reverse flow. Finally, the controller increases the opening percentage of the third ejector and decreases the opening percentage of the second ejector to increase the refrigerant flow rate of the third ejector.

[0010] In one or more embodiments according to the present disclosure, each of the plurality of injectors is a controllable variable injector connected in a parallel configuration.

[0011] In one or more embodiments according to the present disclosure, the plurality of injectors have different capacities.

[0012] In one or more embodiments according to the present disclosure, the plurality of ejectors have throat sections with different diameters.

[0013] In one or more embodiments according to the present disclosure, each of the plurality of injectors is a controllable variable injector having a flow valve upstream of the secondary low-pressure input port.

[0014] In one or more embodiments according to the present disclosure, the controller is adapted to open the flow valve to allow refrigerant flow, and is adapted to close the flow valve to prevent refrigerant flow.

[0015] In one or more embodiments according to the present disclosure, the ejector refrigeration circuit includes a high-pressure ejector circuit and a refrigeration evaporator flow path. The high-pressure ejector circuit includes a heat dissipation heat exchanger, a plurality of ejectors, a receiver, and at least one compressor in the flow direction of the circulating refrigerant. The refrigeration evaporator flow path includes a liquid pump, at least one refrigeration expansion device, and at least one refrigerant evaporator in the flow direction of the circulating refrigerant. The heat dissipation heat exchanger includes an inlet side and an outlet side. Each of the plurality of ejectors includes a primary high-pressure input port, a secondary low-pressure input port, and an output port, so that the primary high-pressure input port is in fluid communication with the outlet side of the heat dissipation heat exchanger. The receiver includes an inlet, a liquid outlet, and a gas outlet, so that the inlet is in fluid communication with the output port of each of the plurality of ejectors. At least one compressor includes an inlet side and an outlet side. The inlet side of at least one compressor is in fluid communication with the gas outlet of the receiver, and the outlet side of at least one compressor is in fluid communication with the inlet side of the heat dissipation heat exchanger. The liquid pump includes an inlet side and an outlet side, so that the inlet side is in fluid communication with the liquid outlet of the receiver. At least one refrigeration expansion device includes an inlet side and an outlet side, so that the inlet side of at least one refrigeration expansion device is in fluid communication with the outlet side of the liquid pump. The at least one refrigeration evaporator includes an inlet side and an outlet side such that the inlet side is in fluid communication with the outlet side of the at least one refrigeration expansion device and the outlet side is in fluid communication with the secondary low pressure input port of each of the plurality of ejectors.

[0016] In one or more embodiments according to the present disclosure, the liquid pump includes a bypass line having a switchable bypass valve for allowing the refrigerant to selectively bypass the liquid pump by opening the switchable bypass valve.

[0017] A method for detecting and correcting backflow in an ejector refrigeration circuit is also disclosed. The method includes measuring an ejector suction superheat of a refrigerant at a secondary low-pressure input port of a corresponding ejector from a plurality of ejectors via each of a plurality of first sensors. Next, at least one second sensor measures the superheat of the refrigerant upstream relative to the secondary low-pressure input port. A controller receives the measured ejector suction superheat and the refrigerant superheat. The controller determines whether the superheat difference between each of the ejector suction superheats measured by the plurality of first sensors and the refrigerant superheat measured by the at least one second sensor falls below a threshold superheat difference. The controller identifies a first ejector from a plurality of ejectors as an ejector affected by backflow based on the determined superheat difference of the first ejector. The controller determines a second ejector from a plurality of ejectors by comparing the opening percentages of the plurality of ejectors so that the second ejector has a maximum opening percentage. Finally, the controller increases the opening percentage of the first ejector and decreases the opening percentage of the second ejector to increase the refrigerant flow rate of the first ejector.

[0018] In one or more embodiments according to the present disclosure, at least one second sensor is located along the refrigeration evaporator flow path between at least one refrigerant evaporator and the secondary low pressure input port.

[0019] In one or more embodiments according to the present disclosure, each of the plurality of ejectors includes a primary high pressure input port, a secondary low pressure input port, and an output port.

[0020] In one or more embodiments according to the present disclosure, identifying the injector affected by the reverse flow includes at least one of the following in order of priority: a) the controller identifies a first injector from the plurality of injectors as an injector affected by reverse flow if only the determined superheat difference of the first injector falls below a threshold superheat difference; b) if the determined superheat difference of more than one injector from the plurality of injectors falls below a threshold superheat difference, the controller identifies an injector from the plurality of injectors having a negative estimated suction flow as an injector affected by reverse flow; c) If the estimated intake flow of none or more than one injector from the plurality of injectors falls below zero, the controller identifies a third injector having a smallest opening percentage as the injector affected by the reverse flow.

[0021] In one or more embodiments according to the present disclosure, if the determined superheat difference of more than one injector from the plurality of injectors falls below a threshold superheat difference, the controller is adapted to determine a third injector and a second injector from the more than one injector by comparing the opening percentages of the more than one injector having a superheat difference below the threshold superheat difference, so that the third injector has a minimum opening percentage and the second injector has a maximum opening percentage. The controller identifies the third injector from the more than one injector having the minimum opening percentage as the injector affected by the reverse flow. The controller increases the opening percentage of the third injector and decreases the opening percentage of the second injector to increase the refrigerant flow rate of the third injector.

[0022] In one or more embodiments according to the present disclosure, each of the plurality of injectors is a controllable variable injector connected in a parallel configuration.

[0023] In one or more embodiments according to the present disclosure, the plurality of injectors have different capacities.

[0024] In one or more embodiments according to the present disclosure, a plurality of ejectors have throat sections of different diameters.

[0025] In one or more embodiments according to the present disclosure, each of the plurality of injectors is a controllable variable injector having a flow valve upstream of the secondary low-pressure input port.

[0026] In one or more embodiments according to the present disclosure, the controller is adapted to open the flow valve to allow refrigerant flow, and is adapted to close the flow valve to prevent refrigerant flow.

[0027] In one or more embodiments according to the present disclosure, the ejector refrigeration circuit includes a high-pressure ejector circuit and a refrigeration evaporator flow path. The high-pressure ejector circuit includes a heat dissipation heat exchanger, a plurality of ejectors, a receiver, and at least one compressor in the flow direction of the circulating refrigerant. The heat dissipation heat exchanger includes an inlet side and an outlet side. Each of the plurality of ejectors includes a main high-pressure input port, a secondary low-pressure input port, and an output port, so that the main high-pressure input port is in fluid communication with the outlet side of the heat dissipation heat exchanger. The receiver includes an inlet, a liquid outlet, and a gas outlet, so that the inlet is in fluid communication with the output port of each of the plurality of ejectors. At least one compressor includes an inlet side and an outlet side, so that the inlet side of at least one compressor is in fluid communication with the gas outlet of the receiver, and the outlet side of at least one compressor is in fluid communication with the inlet side of the heat dissipation heat exchanger. The refrigeration evaporator flow path includes a liquid pump, at least one refrigeration expansion device, and at least one refrigerant evaporator in the flow direction of the circulating refrigerant. The liquid pump includes an inlet side and an outlet side, so that the inlet side is in fluid communication with the liquid outlet of the receiver. At least one refrigeration expansion device includes an inlet side and an outlet side, so that the inlet side of at least one refrigeration expansion device is in fluid communication with the outlet side of the liquid pump. The at least one refrigeration evaporator includes an inlet side and an outlet side such that the inlet side is in fluid communication with the outlet side of the at least one refrigeration expansion device and the outlet side is in fluid communication with the secondary low pressure input port of each of the plurality of ejectors.

[0028] In one or more embodiments according to the present disclosure, the liquid pump includes a bypass line having a switchable bypass valve, and the refrigerant is allowed to selectively bypass the liquid pump by opening the switchable bypass valve.

[0029] In order to further illustrate the advantages and features of the method, system and device, a more specific description will be given to the method, system and device with reference to the specific embodiments thereof shown in the accompanying drawings. It is recognized that these figures only depict typical embodiments of the present disclosure and therefore will not be considered to limit its scope. The present disclosure will be described and explained with additional specificity and details in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] These and other features, aspects and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings, wherein like numerals refer to like parts throughout the drawings, and wherein:

[0031] Figure 1 A schematic diagram of a system for detecting and correcting reverse flow in an ejector refrigeration circuit according to one or more embodiments of the present disclosure is exemplarily shown;

[0032] Figure 2A An example is shown as follows: Figure 1 A schematic cross-sectional view of a controllable injector employed in an exemplary embodiment shown in FIG.

[0033] Figure 2B A schematic cross-sectional view exemplarily shows a controllable injector in a reverse flow state; and

[0034] Figure 3 A flow chart indicating a method for detecting and correcting reverse flow in an ejector refrigeration circuit is illustratively shown.

[0035] Furthermore, the skilled artisan will recognize that the elements in the figures are shown for simplicity and have not necessarily been drawn to scale. For example, a flow chart illustrates the method in terms of the most salient steps involved to help improve understanding of aspects of the present disclosure. Furthermore, depending on the configuration of the device, one or more components of the device may have been represented in the figures by conventional symbols, and the figures may show only those specific details relevant to understanding the embodiments of the present disclosure so as not to obscure the figures with details that would be readily apparent to one of ordinary skill in the art having the benefit of the description herein. DETAILED DESCRIPTION

[0036] For the purpose of promoting an understanding of the principles of the present disclosure, reference will now be made to various embodiments and specific language will be used to describe them. It will be understood, however, that the scope of the present disclosure is not intended to be limited thereby, and such variations and other modifications in the illustrated systems, and such further applications of the principles of the present disclosure as illustrated therein are contemplated as would normally occur to one skilled in the art to which the present disclosure relates.

[0037] It will be understood by those skilled in the art that both the foregoing general description and the following detailed description illustrate the present disclosure and are not intended to limit the present disclosure.

[0038] References throughout this specification to "one aspect," "another aspect," or similar language mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, appearances of the phrases "in one embodiment," "in another embodiment," "some embodiments," "one or more embodiments," and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

[0039] The terms "include", "comprises", or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process or method that includes a series of steps may include not only those steps, but may include other steps not expressly listed or inherent to the process or method. Similarly, without further limitations, one or more devices or subsystems or elements or structures or components preceded by "includes..." do not exclude the presence of other devices or other subsystems or other elements or other structures or other components or additional devices or additional subsystems or additional elements or additional structures or additional components.

[0040] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0041] Figure 1 A schematic diagram of a system 100 for detecting and correcting reverse flow in an ejector refrigeration circuit is illustrated in accordance with one or more embodiments of the present disclosure.

[0042] In an exemplary embodiment according to the present disclosure, the ejector refrigeration circuit includes a high-pressure ejector circuit, which includes a heat dissipation heat exchanger 105, a plurality of ejectors 101, a receiver 106, and at least one compressor 107 in the flow direction of the circulating refrigerant. The ejector refrigeration circuit also includes a refrigeration evaporator flow path, which includes a liquid pump 108, at least one refrigeration expansion device 109, and at least one refrigeration evaporator 110 in the flow direction of the circulating refrigerant.

[0043] The heat dissipation heat exchanger 105 includes an inlet side 105a and an outlet side 105b. The heat dissipation heat exchanger 105 is also interchangeably referred to as a gas cooler unit or a condenser. The heat dissipation heat exchanger 105 is configured to transfer heat from the refrigerant to the environment, thereby reducing the superheat of the refrigerant. In an embodiment, the heat dissipation heat exchanger 105 may include one or more fans for blowing air through the heat dissipation heat exchanger 105 to enhance the heat transfer from the refrigerant to the environment. The type and number of fans used can be adjusted based on the type of condenser used, etc. The cooled refrigerant leaving the heat dissipation heat exchanger 105 at the outlet side 105b is delivered to the main high pressure input port 101a of the plurality of ejectors 101 via a high pressure input line and an optional service valve.

[0044] A plurality of ejectors 101 are adapted to expand the refrigerant to a reduced intermediate pressure level. Each of the plurality of ejectors 101 includes a primary high pressure input port 101a, a secondary low pressure input port 101b, and an output port 101c. The primary high pressure input port 101a is in fluid communication with the outlet side 105b of the heat dissipation heat exchanger 105. The expanded refrigerant leaves the ejector 101 through the corresponding ejector output port 101c and is delivered to the inlet 106a of the receiver 106. In addition, the receiver 106 includes a liquid outlet 106b and a gas outlet 106c, and the inlet 106a is in fluid communication with the output port 101c of each of the plurality of ejectors 101. In the receiver 106, the refrigerant is separated into a liquid portion collected at the bottom portion of the receiver 106 and a gas phase portion collected in the upper portion of the receiver 106 by means of gravity. The gas phase portion of the refrigerant leaves the receiver 106 through a gas outlet 106c provided at an upper portion of the receiver 106 and is delivered to an inlet side 107a of at least one compressor 107, completing the refrigerant cycle of the high-pressure ejector circuit.

[0045] The at least one compressor 107 includes an inlet side 107a and an outlet side 107b. The inlet side 107a of the at least one compressor 107 is in fluid communication with the gas outlet 106c of the receiver 106, and the outlet side 107b of the at least one compressor 107 is in fluid communication with the inlet side 105a of the heat rejection heat exchanger 105.

[0046] The liquid pump 108 includes an inlet side 108a and an outlet side 108b. The inlet side 108a is in fluid communication with the liquid outlet 106b of the receiver 106. In an embodiment, the liquid pump 108 may be located below the receiver 106. Arranging the liquid pump 108 below the receiver 106 allows the liquid refrigerant to be supplied from the receiver 106 to the inlet side 108a of the liquid pump 108 using gravity. The liquid pump 108 also includes a bypass line that includes a switchable bypass valve 111 that allows the refrigerant to selectively bypass the liquid pump 108 by opening the switchable bypass valve 111. In an embodiment, a separate liquid pump 108 and (optional) bypass line may be provided, allowing the pressure of the liquid refrigerant to be adjusted independently.

[0047] At least one refrigeration expansion device 109 includes an inlet side 109a and an outlet side 109b. The inlet side 109a of the at least one refrigeration expansion device 109 is in fluid communication with the outlet side 108b of the liquid pump 108. At least one refrigeration evaporator 110 includes an inlet side 110a and an outlet side 110b. The inlet side 110a is in fluid communication with the outlet side 109b of the at least one refrigeration expansion device 109, and the outlet side 110b is in fluid communication with the secondary low pressure input port 101b of each of the plurality of ejectors 101.

[0048] The system 100 includes a plurality of injectors 101, a plurality of first sensors 102, at least one second sensor 103, and a controller 104. Each of the plurality of injectors 101 includes a primary high-pressure input port 101a, a secondary low-pressure input port 101b, and an output port 101c. In an embodiment, as disclosed in the detailed description of FIG. 2 , each of the plurality of injectors 101 is a controllable variable injector 101. Hereinafter, “injector 101” may be interchangeably referred to as “controllable variable injector 101”. In addition, the plurality of injectors 101 may be connected in parallel to each other or in a parallel configuration. The plurality of injectors 101 may have different capacities or may all be the same capacity. If the plurality of injectors 101 used are controllable variable injectors 101, the plurality of injectors 101 may have a needle 126 ( Figure 2A-2B As used herein, the term "opening percentage" is used to adjust the opening percentage. Figure 2A-2B Detailed description of the invention is defined and described in detail in the detailed description of the invention. Alternatively, each of the plurality of ejectors 101 used may be a controllable variable ejector 101 having a flow valve 112 upstream of the secondary low-pressure input port 101b. In an embodiment, the controller 104 is adapted to open the flow valve 112 to allow refrigerant flow, and is adapted to close the flow valve 112 to prevent refrigerant flow. In this embodiment, the controller 104 actuates the flow valve 112 between the open and closed positions to allow or prevent refrigerant from flowing to the secondary low-pressure input port 101b of the corresponding ejector 101.

[0049] Each of the plurality of first sensors 102 is adapted to measure the ejector suction superheat of the refrigerant at the secondary low pressure input port 101b of the corresponding ejector 101 from the plurality of ejectors 101. The at least one second sensor 103 is located along the refrigeration evaporator flow path between the at least one refrigerant evaporator 110 and the secondary low pressure input port 101b. Thus, the at least one second sensor 103 is adapted to measure the superheat of the refrigerant upstream relative to the secondary low pressure input port 101b. The controller 104 communicates with each of the plurality of first sensors 102 and the at least one second sensor 103.

[0050] As used herein, the term "superheat" refers to the increase in the temperature of the refrigerant vapor compared to the boiling point of the refrigerant at a given pressure. At different pressures, the boiling point of the refrigerant is different. As the operating pressure of the system 100 changes, the boiling point of the refrigerant also changes. When a plurality of first sensors 102 measure the ejector suction superheat of the refrigerant at the secondary low-pressure input port 101b, this means that a plurality of first sensors 102 measure the difference between the temperature of the refrigerant vapor at the secondary low-pressure input port 101b and the boiling point of the refrigerant at the current operating pressure of the system 100. Similarly, when at least one second sensor 103 measures the superheat of the refrigerant upstream relative to the secondary low-pressure input port 101b, this means that at least one second sensor 103 measures the difference between the temperature of the refrigerant vapor upstream relative to the secondary low-pressure input port 101b and the boiling point of the refrigerant at the current operating pressure of the system 100.

[0051] As used herein, the "controller 104" may be configured to control at least one compressor 107, a liquid pump 108, a flow valve 112, and / or a plurality of ejectors 101 (if at least one of the plurality of ejectors 101 is variable) based on one or more parameters (e.g., pressure values, superheat values ​​measured by the plurality of first sensors 102 and the at least one second sensor 103) for operating the ejector refrigeration circuit as efficiently as possible. In an embodiment, the controller 104 may refer to a single controller 104, or may be understood to include one or a combination of a microprocessor, suitable logic, circuit, printed circuit board (PCB), audio interface, visual interface, tactile interface, etc. The controller 104 may include, but is not limited to, a microcontroller, a reduced instruction set computing (RISC) processor, an application specific integrated circuit (ASIC) processor, a complex instruction set computing (CISC) processor, a central processing unit (CPU), a graphics processing unit (GPU), a state machine, and / or other processing units or circuits.

[0052] The controller 104 may also include suitable logic, circuitry, interfaces, and / or code that may be configured to execute a set of instructions stored in a memory unit. In an exemplary embodiment of a memory unit according to the present disclosure, the memory unit may include, but is not limited to, an electrically erasable programmable read-only memory (EEPROM), a random access memory (RAM), a read-only memory (ROM), a hard disk drive (HDD), a flash memory, a solid-state drive (SSD), and / or a CPU cache memory.

[0053] The controller 104 may also include a communication unit suitable for communicating with the computing device via a communication network. The communication unit may be composed of, for example, a telematics transceiver (DCM), a distress battery, a GPS, a data communication module ASSY, a telephone microphone ASSY, and a telephone antenna ASSY. The communication network may include, but is not limited to, a wide area network (WAN), a cellular network (such as a 3G, 4G, or 5G network), an Internet-based mobile ad hoc network (IMANET), and the like. The communication network may also include wired media (such as a wired network or a direct wired connection) and wireless media (such as acoustic, radio frequency (RF), microwave, infrared (IR), and other wireless media). In an embodiment, the computing device may be implemented as part of a small form factor portable (or mobile) electronic device, such as a mobile phone, a personal data assistant (PDA), a personal media player device, a wireless network monitoring device, a personal headset device, a dedicated device, or a hybrid device including any of the above functions.

[0054] In an exemplary embodiment, the controller 104 may receive power from a suitably coupled power source (not shown). For example, a battery or power source may be electrically coupled to supply electrical power to the controller 104. In an embodiment, the power source may be, for example, a battery, such as a rechargeable battery or a non-rechargeable battery. For example, examples of suitable batteries include lithium batteries (such as lithium-ion batteries), nickel batteries (such as nickel-cadmium batteries), and alkaline batteries.

[0055] The controller 104 is adapted to receive the ejector suction superheat measured by the plurality of first sensors 102 and the refrigerant superheat measured by the at least one second sensor 103. Next, the controller 104 determines whether the superheat difference between each of the ejector suction superheat measured by the plurality of first sensors 102 and the refrigerant superheat measured by the at least one second sensor 103 falls below a threshold superheat difference. In an embodiment, the threshold superheat difference may be defined by a user, which means that the threshold superheat difference may be set and adjusted or modified based on the performance or capacity of the ejector refrigeration circuit.

[0056] If the determined superheat difference of the first ejector 101' falls below the threshold superheat difference, the controller 104 identifies the first ejector 101' from the plurality of ejectors 101 as an ejector affected by backflow. Next, the controller 104 determines the second ejector 101' from the plurality of ejectors 101 by comparing the opening percentages of the plurality of ejectors 101, such that the second ejector 101' includes the maximum opening percentage. It can be appreciated that the second ejector 101' is determined from the plurality of ejectors 101 other than the identified first ejector 101'. Finally, the controller 104 simultaneously increases the opening percentage of the first ejector 101' and decreases the opening percentage of the second ejector 101' to increase the refrigerant flow rate of the first ejector 101'. The recovery step is performed by increasing the opening percentage of the first ejector 101', which is the ejector 101 affected by the reverse flow, and simultaneously reducing the opening percentage of the second ejector 101" having the largest opening percentage. The recovery step is performed until the superheat difference between the ejector suction superheat and the refrigerant superheat measured by the at least one second sensor 103 falls within the threshold superheat difference. The recovery step ensures that the motive flow rate in the inlet 106a of the receiver 106 remains constant while preventing the high pressure in the ejector refrigeration circuit from being maintained.

[0057] Under nominal conditions, i.e. when the ejector 101 is not under counterflow, the refrigerant superheat measured by the at least one second sensor 103 may be between 8 K and 14 K. Figure 2A Under the nominal conditions shown in , the ejector suction superheat of each of the ejectors 101 is a few Kelvins higher than the refrigerant superheat measured by the at least one second sensor 103, for example 1K, 2K, etc. Therefore, the threshold superheat difference between the ejector suction superheat and the refrigerant superheat may be in the range of 4-5K. Alternatively, when Figure 2B When reverse flow occurs as shown in , the threshold superheat difference falls below 4K, and the ejector suction superheat of the ejector 101 affected by the reverse flow may drop to zero.

[0058] Alternatively, a situation may occur where more than one injector 101 has a superheat difference below a threshold superheat difference. If the determined superheat difference of more than one injector 101 from the plurality of injectors 101 falls below the threshold superheat difference, the controller 104 is adapted to determine a third injector 101'' and a second injector 101'' from the more than one injectors 101 by comparing the opening percentages of the more than one injectors 101 having a superheat difference below the threshold superheat difference, such that the third injector 101'' comprises a minimum opening percentage and the second injector 101'' comprises a maximum opening percentage.

[0059] refer to Figure 1, if the determined superheat difference of the first injector 101', the second injector 101", and the third injector 101'" falls below the threshold superheat difference, the controller 104 identifies the injector (101', 101", or 101'"') having a negative estimated suction flow (via the mathematical model) as an injector affected by backflow. If none of the multiple injectors 101 meet the condition of the negative estimated suction flow, or if more than one injector (e.g., the first injector 101', the second injector 101", and the third injector 101'"') meet the condition of the negative estimated suction flow, the injector with the smallest opening percentage is selected. For example, if the second injector 101" has the largest opening percentage and the third injector 101'" has the smallest opening percentage, the controller 104 identifies the third injector 101'"' as an injector affected by backflow.

[0060] The controller 104 continues from more than one ejector 101 to identify the third ejector 101'" having the smallest opening percentage as the ejector 101 affected by the reverse flow. Finally, the controller 104 performs a recovery step by simultaneously increasing the opening percentage of the third ejector 101'" and decreasing the opening percentage of the second ejector 101" to increase the refrigerant flow rate of the third ejector 101'". The recovery step is performed until the superheat difference between the ejector suction superheat and the refrigerant superheat measured by the at least one second sensor 103 falls within a threshold superheat difference.

[0061] In summary, an injector is identified by the controller 104 as an injector 101 affected by reverse flow if at least one of the following conditions is met in order of priority: 1) If the determined superheat difference of only one ejector (e.g., the first ejector 101') falls below a threshold superheat difference, the controller 104 identifies the first ejector 101' from the plurality of ejectors 101 as an ejector affected by reverse flow. The threshold superheat difference between the ejector suction superheat and the refrigerant superheat may range between 4-5K. Alternatively, when Figure 2B When reverse flow occurs as shown in , the threshold superheat difference falls below 4K, and the ejector suction superheat of the ejector 101 affected by the reverse flow may drop to zero. 2) If more than one injector 101 from the plurality of injectors 101 meets the above condition, the injector with the negative estimated (via the mathematical model) suction flow is identified as the injector 101 affected by the reverse flow. 3) If none or more than one injector 101 satisfies the aforementioned conditions, the injector 101 (e.g., the third injector 101'") having the smallest opening percentage is identified as the injector affected by the backflow. This means that if the estimated suction flow of none or more than one injector from the plurality of injectors falls below zero, the third injector 101'" having the smallest opening percentage is identified as the injector affected by the backflow. Only one injector can be identified as being in a backflow state. Finally, the controller 104 performs a recovery step by simultaneously increasing the opening percentage of the third injector 101'" and decreasing the opening percentage of the second injector 101" to increase the refrigerant flow rate of the third injector 101'". The recovery step is performed until the superheat difference between the injector suction superheat and the refrigerant superheat measured by at least one second sensor 103 falls within the threshold superheat difference. By following this procedure, a nearly constant motive flow and high pressure are maintained. This minimizes the impact on the high pressure control loop.

[0062] Figure 2A An example is shown as follows: Figure 1 Schematic cross-sectional view of a controllable variable ejector 101 employed in an exemplary embodiment shown in . Each of the plurality of ejectors 101 includes a primary high pressure input port 101a, a secondary low pressure input port 101b, and an output port 101c. The ejector 101 is formed by a power nozzle 113 nested in an external component 114. The primary high pressure input port 101a forms an inlet to the power nozzle 113. The outlet of the external component 114 provides an output port 101c of the ejector 101. The main refrigerant stream 115 enters the primary high pressure input port 101a, and then enters the convergent section 116 of the power nozzle 113. Then, the main refrigerant stream 115 passes through the throat section 117 and the divergent expansion section 118 to the outlet 119 of the power nozzle 113. The power nozzle 113 accelerates the main refrigerant stream 115 and reduces the pressure of the main refrigerant stream 115. The secondary low pressure input port 101b forms the inlet of the external component 114. The pressure reduction caused by the power nozzle 113 to the mainstream draws the secondary flow 120 into the outer member 114. The outer member 114 includes a mixer having a converging section 121 and an elongated throat or mixing section 122. The outer member 114 also has a diverging section or diffuser 123 downstream of the elongated throat or mixing section 122. The outlet 119 of the power nozzle 113 is positioned within the converging section 121. When the main refrigerant flow 115 leaves the outlet 119, the main refrigerant flow 115 begins to mix with the secondary flow 120, wherein further mixing occurs through the elongated throat or mixing section 12 that provides a mixing zone. Therefore, the corresponding main flow path and the secondary flow path extend from the main high pressure input port 101a and the secondary low pressure input port 101b to the output port 101c, respectively, and converge at the outlet.

[0063] In operation, the primary refrigerant stream 115 may be supercritical when entering the controllable variable ejector 101, and may be subcritical when leaving the motive nozzle 113. The secondary stream 120 may be gaseous or a mixture of gas and a small amount of liquid when entering the secondary low pressure input port 101b. The resulting combined stream 124 is a liquid / vapor mixture, and is decelerated and restored to pressure in the diffuser 123 while still being a mixture.

[0064] The controllability of the controllable variable ejector 101 is provided by a needle valve 125 having a needle 126 and an actuator 127. The actuator 127 is adapted to move the tip portion 128 of the needle 126 into and out of the throat section 117 of the power nozzle 113 to adjust the main refrigerant flow 115 through the power nozzle 113 and then through the entire controllable variable ejector 101. In an embodiment, each of the plurality of ejectors 101 may have a throat section 117 with a different diameter. Alternatively, each of the plurality of ejectors 101 may have a throat section 117 with an equal diameter. As used throughout this document, the term "opening percentage" refers to the percentage of the opening of the throat section 117. When the tip portion 128 of the needle 126 moves into the throat section 117, the opening percentage is reduced to zero percent. Similarly, when the tip portion 128 moves completely out of the throat section 117, the opening percentage increases to 100%. Therefore, by actuating the tip portion of the needle 126 into and out of the throat section 117 of the motive nozzle 113, the opening percentage of the throat section 117 is controlled to a range between 0-100%, such that an opening percentage of zero percent completely restricts the main refrigerant flow 115, and an opening percentage of 100% fully allows the main refrigerant flow 115.

[0065] In an embodiment, the actuator 127 may be an electric actuator, such as a solenoid or the like. Figure 1 The controller 104 disclosed in the detailed description of can be connected to the actuator 127 and other controllable components of the controllable variable injector 101 using hard wiring or wireless communication paths. The controller 104 can store mathematical models to estimate the suction and power flow rates. Thus, the controller 104 can extract signals from sensors (such as temperature sensors, pressure sensors, etc.) to determine one or more parameters for use in the mathematical model. For example, the controller uses power pressure, power temperature, the diameter of the injector needle opening, diffuser pressure, suction pressure, etc. to dynamically estimate the suction flow rate and power flow rate during operation. This allows the controller 104 to improve the accuracy of backflow detection.

[0066] Figure 2BA schematic cross-sectional view of the controllable ejector 101 in a reverse flow state is exemplarily shown. When affected by the reverse flow state, the combined flow 124 reverses and moves from the output port 101c to the secondary low pressure input port 101b. The combined flow 124 mixes with the main refrigerant flow 115 and combines with the secondary flow 120 to exit through the secondary low pressure input port 101b.

[0067] Figure 3 A flow chart is shown indicative of a method 300 for detecting and correcting reverse flow in an ejector refrigeration circuit. Figure 3 The steps are shown and described in a particular order, but according to various embodiments of the present disclosure, the steps may occur in a different order. Figure 1-3 The descriptions covered Figure 3 Details related to the various steps of the ejector refrigeration circuit are not discussed in detail here for the sake of brevity. A method 300 for detecting and correcting reverse flow in an ejector refrigeration circuit is disclosed.

[0068] At step 301, each of the plurality of first sensors 102 measures the ejector suction superheat of the refrigerant at the secondary low-pressure input port 101b of the corresponding ejector 101 from the plurality of ejectors 101. As exemplarily shown in FIG. 2 , each of the plurality of ejectors 101 includes a primary high-pressure input port 101a, a secondary low-pressure input port 101b, and an output port 101c.

[0069] At step 303, at least one second sensor 103 measures superheat of the refrigerant upstream relative to the secondary low pressure input port 101b. The at least one second sensor 103 is located along the refrigeration evaporator flow path between the at least one refrigerant evaporator 110 and the secondary low pressure input port 101b.

[0070] At step 305 , the controller 104 receives the ejector suction superheat measured by the plurality of first sensors 102 and the refrigerant superheat measured by the at least one second sensor 103 .

[0071] At step 307 , the controller 104 determines whether a superheat difference between each of the ejector suction superheats measured by the plurality of first sensors 102 and the refrigerant superheat measured by the at least one second sensor 103 falls below a threshold superheat difference.

[0072] At step 309 , the controller 104 identifies a first injector 101 ′ from the plurality of injectors 101 as an injector affected by the reverse flow based on the determined superheat difference of the first injector 101 ′.

[0073] Alternatively, a situation may occur in which more than one injector 101 has a superheat difference below a threshold superheat difference. If the determined superheat difference of more than one injector 101 from the plurality of injectors 101 falls below the threshold superheat difference, the controller 104 is adapted to determine a third injector 101'' and a second injector 101'' from the more than one injectors 101 by comparing the opening percentages of the more than one injectors 101 having a superheat difference below the threshold superheat difference, such that the third injector 101'' includes the minimum opening percentage and the second injector 101'' includes the maximum opening percentage. Since the third injector 101'' has the minimum opening percentage, the controller 104 identifies the third injector 101'' from the more than one injectors 101 having a superheat difference below the threshold superheat difference as an injector 101 affected by backflow. It can be appreciated that the criterion for identifying an injector 101 affected by backflow is the minimum opening percentage. Thus, the ejector 101 having the smallest opening percentage from among the plurality of ejectors 101 is identified as the ejector 101 affected by the reverse flow. Finally, the controller 104 performs a recovery step by simultaneously increasing the opening percentage of the third ejector 101'' and decreasing the opening percentage of the second ejector 101'' to increase the refrigerant flow rate of the third ejector 101''. The recovery step is performed until the superheat difference between the ejector suction superheat and the refrigerant superheat measured by the at least one second sensor 103 falls within the threshold superheat difference.

[0074] In summary, identification of an injector by the controller 104 as an injector 101 affected by reverse flow is based on the following conditions being met in order of priority: 1) If the determined superheat difference of only one ejector (e.g., the first ejector 101') falls below a threshold superheat difference, the controller 104 identifies the first ejector 101' from the plurality of ejectors 101 as an ejector affected by reverse flow. The threshold superheat difference between the ejector suction superheat and the refrigerant superheat may range between 4-5K. Alternatively, when Figure 2B When reverse flow occurs as shown in , the threshold superheat difference falls below 4K, and the ejector suction superheat of the ejector 101 affected by the reverse flow may drop to zero. 2) If more than one injector 101 from the plurality of injectors 101 meets the above condition, the injector with the negative estimated (via the mathematical model) suction flow is identified as the injector 101 affected by the reverse flow. 3) If none or more than one injector 101 satisfies the aforementioned conditions, the injector 101 (e.g., the third injector 101'") having the smallest opening percentage is identified as the injector affected by the backflow. This means that if the estimated suction flow of none or more than one injector from the plurality of injectors falls below zero, the third injector 101'" having the smallest opening percentage is identified as the injector affected by the backflow. Only one injector can be identified as being in a backflow state. Finally, the controller 104 performs a recovery step by simultaneously increasing the opening percentage of the third injector 101'" and decreasing the opening percentage of the second injector 101" to increase the refrigerant flow rate of the third injector 101'". The recovery step is performed until the superheat difference between the injector suction superheat and the refrigerant superheat measured by at least one second sensor 103 falls within the threshold superheat difference. By following this procedure, a nearly constant motive flow and high pressure are maintained. This minimizes the impact on the high pressure control loop.

[0075] At step 311 , the controller 104 determines a second injector 101 ″ from the plurality of injectors 101 by comparing the opening percentages of the plurality of injectors 101 such that the second injector 101 ″ includes a maximum opening percentage.

[0076] At step 313 , the controller increases the opening percentage of the first ejector 101 ′ and decreases the opening percentage of the second ejector 101 ″ to increase the refrigerant flow rate of the first ejector 101 ′.

[0077] Existing ejector control systems preset ejectors 101 that can be used simultaneously. These preset opening configurations (e.g., increasing the opening percentage of the first ejector 101', then decreasing the opening percentage of the second ejector 101", etc.) can be safe for reverse flow. However, by limiting the opening percentages to a preset sequence, the ejector refrigeration circuit is prevented from achieving optimal performance. Dynamically detecting an ejector 101 affected by reverse flow based on a determined superheat difference falling below a threshold superheat difference allows the controller 104 to proactively perform recovery steps. This feature helps optimize the overall efficiency of the ejector refrigeration circuit.

[0078] Existing algorithms detect reverse flow by monitoring the ejector's ejector suction superheat close to zero. Such systems have a slow reaction time because reverse flow is detected when it is already in a serious state. Including at least one second sensor 103 located along the refrigeration evaporator flow path between at least one refrigerant evaporator 110 and the secondary low pressure input port 101b allows the superheat of the refrigerant upstream relative to the secondary low pressure input port 101b to be measured. This feature allows the controller 104 to detect reverse flow earlier when the ejector suction superheat of the ejector 101 is much higher than zero, thereby reducing recovery time and performance loss.

[0079] Existing algorithms recover from reverse flow by opening only the injectors 101 detected to be in reverse flow, causing an increase in motive flow and a decrease in motive pressure. This affects the high pressure injector circuit, which attempts to maintain the high pressure within the system 100 to a predetermined optimal value. The controller 104 reduces the impact on the high pressure injector circuit by maintaining the motive flow and high pressure nearly constant through a recovery step in which the injector 101 having the largest opening percentage among the plurality of injectors 101 is simultaneously reduced in opening percentage while increasing the opening percentage of the injector 101 affected by the reverse flow.

[0080] Although specific language has been used to describe the subject matter, it is not intended that any limitation is thereby created. It will be clear to those skilled in the art that various work modifications may be made to the method in order to implement the inventive concept as taught herein. The figures and the preceding description give examples of embodiments. Those skilled in the art will recognize that one or more of the elements described may be well combined into a single functional element. Alternatively, certain elements may be divided into a plurality of functional elements. Elements from one embodiment may be added to another embodiment.

Claims

1. A system for detecting and correcting reverse flow in an ejector refrigeration circuit, the system comprising: a plurality of injectors, each of the plurality of injectors having a primary high pressure input port, a secondary low pressure input port, and an output port; a plurality of first sensors, each of the plurality of first sensors adapted to measure an ejector suction superheat of refrigerant at a secondary low pressure input port of a corresponding ejector from the plurality of ejectors; at least one second sensor located along a refrigeration evaporator flow path between at least one refrigerant evaporator and said secondary low pressure input port, said at least one second sensor being adapted to measure a superheat of said refrigerant upstream relative to said secondary low pressure input port; as well as A controller adapted to: receiving ejector suction superheat measured by the plurality of first sensors and refrigerant superheat measured by the at least one second sensor; determining whether a superheat difference between each of the ejector suction superheats and the refrigerant superheat falls below a threshold superheat difference; identifying a first injector from the plurality of injectors as an injector affected by reverse flow based on the determined superheat difference; determining a second injector from the plurality of injectors by comparing the opening percentages of the plurality of injectors, wherein the second injector comprises a maximum opening percentage; The opening percentage of the first ejector is increased and the opening percentage of the second ejector is decreased to increase the refrigerant flow rate of the first ejector.

2. The system according to claim 1, wherein: Identifying the injector affected by the reverse flow includes at least one of the following in order of priority: the controller identifying a first injector from the plurality of injectors as the injector affected by reverse flow if only the determined superheat difference of the first injector falls below the threshold superheat difference; if the determined superheat difference of more than one injector from the plurality of injectors falls below the threshold superheat difference, the controller identifying an injector from the plurality of injectors having a negative estimated suction flow as the injector affected by reverse flow; If the estimated intake flow of none or more than one injector from the plurality of injectors falls below zero, the controller identifies a third injector having a minimum opening percentage as the injector affected by reverse flow.

3. The system according to claim 1, wherein: If the determined superheat difference from more than one injector of the plurality of injectors falls below the threshold superheat difference, the controller is adapted to: determining a third injector from the more than one injectors and the second injector by comparing opening percentages of more than one injector having a superheat difference below the threshold superheat difference, wherein the third injector comprises a minimum opening percentage and the second injector comprises a maximum opening percentage; identifying the third injector from the more than one injectors comprising the minimum opening percentage as an injector affected by reverse flow; and The opening percentage of the third ejector is increased and the opening percentage of the second ejector is decreased to increase the refrigerant flow rate of the third ejector.

4. The system according to claim 1, wherein: Each of the plurality of injectors is a controllable variable injector connected in a parallel configuration.

5. The system according to claim 1, wherein: The plurality of injectors have different capacities.

6. The system according to claim 1, wherein: The plurality of ejectors have throat sections of different diameters.

7. The system according to claim 1, wherein: Each of the plurality of injectors is a controllable variable injector having a flow valve upstream of the secondary low-pressure input port.

8. The system according to claim 7, wherein: The controller is adapted to open the flow valve to allow refrigerant flow and to close the flow valve to prevent refrigerant flow.

9. The system according to claim 1, wherein: The ejector refrigeration circuit comprises: The high-pressure ejector circuit comprises, in the flow direction of the circulating refrigerant: a heat rejection heat exchanger having an inlet side and an outlet side; the plurality of ejectors, each of the plurality of ejectors having a primary high pressure input port, a secondary low pressure input port, and an output port, wherein the primary high pressure input port is in fluid communication with an outlet side of the heat rejection heat exchanger; a receiver having an inlet, a liquid outlet, and a gas outlet, the inlet being in fluid communication with an output port of each of the plurality of ejectors; at least one compressor having an inlet side and an outlet side, the inlet side of the at least one compressor being in fluid communication with the gas outlet of the receiver and the outlet side of the at least one compressor being in fluid communication with the inlet side of the heat rejection heat exchanger; and A refrigeration evaporator flow path, which includes, in the flow direction of the circulating refrigerant: a liquid pump having an inlet side and an outlet side, the inlet side being in fluid communication with the liquid outlet of the receiver; at least one refrigeration expansion device having an inlet side and an outlet side, the inlet side of the at least one refrigeration expansion device being in fluid communication with the outlet side of the liquid pump; and At least one refrigeration evaporator has an inlet side and an outlet side, the inlet side being in fluid communication with the outlet side of the at least one refrigeration expansion device and the outlet side being in fluid communication with the secondary low pressure input port of each of the plurality of ejectors.

10. The system according to claim 9, wherein: The liquid pump comprises a bypass line having a switchable bypass valve for allowing refrigerant to selectively bypass the liquid pump by opening the switchable bypass valve.

11. A method for detecting and correcting reverse flow in an ejector refrigeration circuit, the method comprising: measuring, via each of the plurality of first sensors, an ejector suction superheat of refrigerant at a secondary low pressure input port of a corresponding ejector from the plurality of ejectors; measuring, via at least one second sensor, a superheat of the refrigerant upstream relative to the secondary low pressure input port; receiving, via a controller, a measured ejector suction superheat and said refrigerant superheat; determining, via the controller, whether a superheat difference between each of the ejector suction superheats measured by the plurality of first sensors and a refrigerant superheat measured by the at least one second sensor falls below a threshold superheat difference; identifying, via the controller, a first injector from the plurality of injectors as an injector affected by reverse flow based on a determined superheat difference of the first injector; determining, via the controller, a second injector from the plurality of injectors by comparing opening percentages of the plurality of injectors, wherein the second injector comprises a maximum opening percentage; as well as The opening percentage of the first ejector is increased and the opening percentage of the second ejector is decreased via the controller to increase the refrigerant flow rate of the first ejector.

12. The method according to claim 11, wherein: The at least one second sensor is located along a refrigeration evaporator flow path between at least one refrigerant evaporator and the secondary low pressure input port.

13. The method according to claim 11, wherein: Each of the plurality of ejectors includes a primary high pressure input port, a secondary low pressure input port, and an output port.

14. The method according to claim 11, wherein: Identifying the injector affected by the reverse flow includes at least one of the following in order of priority: the controller identifying a first injector from the plurality of injectors as the injector affected by reverse flow if only the determined superheat difference of the first injector falls below the threshold superheat difference; if the determined superheat difference of more than one injector from the plurality of injectors falls below the threshold superheat difference, the controller identifying an injector from the plurality of injectors having a negative estimated suction flow as the injector affected by reverse flow; If the estimated intake flow of none or more than one injector from the plurality of injectors falls below zero, the controller identifies a third injector having a minimum opening percentage as the injector affected by reverse flow.

15. The method according to claim 11, wherein: If the determined superheat difference from more than one injector of the plurality of injectors falls below the threshold superheat difference, the controller is adapted to: determining a third injector from the more than one injectors and the second injector by comparing opening percentages of more than one injector having a superheat difference below the threshold superheat difference, wherein the third injector comprises a minimum opening percentage and the second injector comprises a maximum opening percentage; identifying the third injector from the more than one injectors comprising the minimum opening percentage as an injector affected by reverse flow; and The opening percentage of the third ejector is increased and the opening percentage of the second ejector is decreased to increase the refrigerant flow rate of the third ejector.

16. The method according to claim 11, wherein: Each of the plurality of injectors is a controllable variable injector connected in a parallel configuration.

17. The method according to claim 11, wherein: The plurality of injectors have different capacities.

18. The method according to claim 11, wherein: The plurality of ejectors have throat sections of different diameters.

19. The method according to claim 11, wherein: Each of the plurality of injectors is a controllable variable injector having a flow valve upstream of the secondary low-pressure input port.

20. The method according to claim 19, wherein: The controller is adapted to open the flow valve to allow refrigerant flow and to close the flow valve to prevent refrigerant flow.

21. The method according to claim 11, wherein: The ejector refrigeration circuit comprises: The high-pressure ejector circuit comprises, in the flow direction of the circulating refrigerant: a heat rejection heat exchanger having an inlet side and an outlet side; the plurality of ejectors, each of the plurality of ejectors having a primary high pressure input port, a secondary low pressure input port, and an output port, wherein the primary high pressure input port is in fluid communication with an outlet side of the heat rejection heat exchanger; a receiver having an inlet, a liquid outlet, and a gas outlet, the inlet being in fluid communication with an output port of each of the plurality of ejectors; at least one compressor having an inlet side and an outlet side, the inlet side of the at least one compressor being in fluid communication with the gas outlet of the receiver and the outlet side of the at least one compressor being in fluid communication with the inlet side of the heat rejection heat exchanger; and A refrigeration evaporator flow path, which includes, in the flow direction of the circulating refrigerant: a liquid pump having an inlet side and an outlet side, the inlet side being in fluid communication with the liquid outlet of the receiver; at least one refrigeration expansion device having an inlet side and an outlet side, the inlet side of the at least one refrigeration expansion device being in fluid communication with the outlet side of the liquid pump; and At least one refrigeration evaporator has an inlet side and an outlet side, the inlet side being in fluid communication with the outlet side of the at least one refrigeration expansion device and the outlet side being in fluid communication with the secondary low pressure input port of each of the plurality of ejectors.

22. The method according to claim 11, wherein: The liquid pump includes a bypass line including a switchable bypass valve that allows refrigerant to selectively bypass the liquid pump by opening the switchable bypass valve.

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