System and method for controlling multiple injectors in injector refrigeration circuit

Abstract

A system for controlling a plurality of injectors in an injector refrigeration circuit includes a plurality of injectors and a controller. Each of the plurality of injectors includes a primary high pressure input port, a secondary low pressure input port, and an output port. A controller is coupled to each of the plurality of injectors and is adapted to generate a plurality of maps based on a set of predetermined conditions. Each of the plurality of maps is associated with a corresponding temperature of the heat rejection heat exchanger. The controller identifies, from a plurality of maps, a first map associated with a first temperature of the heat rejection heat exchanger and an input signal from the first injector indicative of a flow rate of refrigerant fluid through the first injector. Finally, the controller adjusts a percentage of opening of the plurality of injectors based on the identified first map.

Description

Technical Field

[0001] The present disclosure relates generally to ejector refrigeration circuits. More particularly, the present disclosure relates to a system for controlling a plurality of ejectors in an ejector refrigeration circuit. Background Art

[0002] Ejectors are sometimes used to increase the overall efficiency of commercial refrigeration systems. Ejectors improve efficiency in refrigeration systems by using high pressure to help compress low pressure gas, rather than relying solely on the compressor.

[0003] Typically, the ejector may be located between the outlet of the condenser and the inlet of the receiving 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 condenser 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 typically be both a liquid phase and a gas phase. The gas phase will be fed back to the compressor, while the liquid phase feed passes through another expansion valve and then the evaporator. The fluid leaving the evaporator then flows to the low-pressure inlet of the ejector. The inclusion of the ejector reduces the load on the compressor because the compressor can operate with a lower pressure difference and use less energy because the ejector partially compresses the refrigerant vapor to a medium pressure level.

[0004] Existing control systems dynamically control ejectors in a multi-ejector refrigeration circuit. However, when the ejectors are 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, an improved ejector control system that optimizes machine performance while avoiding ejector backflow is desirable. Summary of the invention

[0005] This summary is provided to introduce a selection of concepts in a simplified form that are further described in the detailed description of the disclosure. This summary is not intended to identify the key or essential inventive concepts of the disclosure, nor is it intended to determine the scope of the disclosure.

[0006] A system for controlling a plurality of ejectors in an ejector refrigeration circuit is disclosed. The system includes a plurality of ejectors and a controller. Each of the plurality of ejectors has a primary high-pressure input port, a secondary low-pressure input port, and an output port. The controller is coupled to each of the plurality of ejectors. The controller is adapted to generate a plurality of maps based on a set of predetermined conditions, such that each of the plurality of maps is associated with a corresponding temperature of a heat rejection heat exchanger. Next, the controller identifies from the plurality of maps a first map associated with a first temperature of the heat rejection heat exchanger and an input signal indicating a flow rate of a refrigerant fluid passing through the first ejector. Finally, the controller adjusts the opening percentages of the plurality of ejectors based on the identified first map.

[0007] In one or more embodiments according to the present disclosure, each of the plurality of maps indicates a rate of change of a flow rate of refrigerant fluid passing through each of the plurality of ejectors based on a change in an opening percentage of each of the plurality of ejectors during a corresponding temperature of the heat rejection heat exchanger.

[0008] In one or more embodiments according to the present disclosure, each of the plurality of maps includes a plurality of stages, and an opening percentage of at least a first injector from the plurality of injectors is greater than zero in each of the plurality of stages.

[0009] In one or more embodiments according to the present disclosure, the plurality of stages include at least a first stage, a second stage, and a third stage. During the first stage, the opening percentages of the plurality of injectors other than the first injector are equal to zero. During the second stage, the opening percentages of the plurality of injectors other than the first injector and the second injector are equal to zero. Furthermore, during the third stage, the opening percentages of the plurality of injectors other than the first injector, the second injector, and the third injector are equal to zero.

[0010] In one or more embodiments according to the present disclosure, the grouped predetermined conditions include the following: (a) The opening percentage of multiple injectors increases within the stage; (b) when switching between the plurality of stages of each of the plurality of maps, the opening percentages of the plurality of ejectors are adjusted to maintain a constant flow rate of the refrigerant fluid; (c) when switching between the plurality of stages in each of the plurality of maps, the opening percentage of the plurality of injectors is greater than zero; and (d) A flow rate of the refrigerant fluid passing through the second low pressure input port of each of the plurality of ejectors is greater than zero.

[0011] 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.

[0012] In one or more embodiments according to the present disclosure, the plurality of injectors have at least one of different capacities and equal capacities.

[0013] 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 rejection heat exchanger having an inlet side and an outlet side, a plurality of ejectors, a receiver, and at least one compressor in the flow direction of the circulating refrigerant. Each of the plurality of ejectors has 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 rejection heat exchanger. The receiver includes an inlet, a liquid outlet, and a gas outlet. 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 rejection heat exchanger. The refrigeration evaporator flow path includes a liquid pump, at least one refrigeration expansion device, and at least one refrigeration 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. 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. The inlet side is in fluid communication with the outlet side of 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.

[0014] 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.

[0015] A method for controlling a plurality of ejectors in an ejector refrigeration circuit is also disclosed. The method includes the following steps: generating, via a controller, a plurality of maps based on a set of predetermined conditions, such that each of the plurality of maps is associated with a corresponding temperature of a heat rejection heat exchanger. Next, the controller identifies from the plurality of maps a first map associated with a first temperature of the heat rejection heat exchanger and an input signal indicating a flow rate of a refrigerant fluid passing through the first ejector. Finally, the controller adjusts the opening percentages of the plurality of ejectors based on the identified first map.

[0016] In one or more embodiments according to the present disclosure, each of the plurality of maps indicates a rate of change of a flow rate of refrigerant fluid passing through each of the plurality of ejectors based on a change in an opening percentage of each of the plurality of ejectors during a corresponding temperature of the heat rejection heat exchanger.

[0017] In one or more embodiments according to the present disclosure, each of the plurality of maps includes a plurality of stages, and an opening percentage of at least a first injector from the plurality of injectors is greater than zero in each of the plurality of stages.

[0018] In one or more embodiments according to the present disclosure, the plurality of stages include at least a first stage, a second stage, and a third stage. During the first stage, the opening percentages of the plurality of injectors other than the first injector are equal to zero. During the second stage, the opening percentages of the plurality of injectors other than the first injector and the second injector are equal to zero. During the third stage, the opening percentages of the plurality of injectors other than the first injector, the second injector, and the third injector are equal to zero.

[0019] In one or more embodiments according to the present disclosure, the grouped predetermined conditions include the following: (a) The opening percentage of multiple injectors increases within the stage; (b) when switching between the plurality of stages of each of the plurality of maps, the opening percentages of the plurality of ejectors are adjusted to maintain a constant flow rate of the refrigerant fluid; (c) when switching between the plurality of stages in each of the plurality of maps, the opening percentage of the plurality of injectors is greater than zero; and (d) A flow rate of the refrigerant fluid passing through the second low pressure input port of each of the plurality of ejectors is greater than zero.

[0020] 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.

[0021] 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.

[0022] In one or more embodiments according to the present disclosure, the plurality of injectors have at least one of different capacities and equal capacities.

[0023] 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 rejection heat exchanger having an inlet side and an outlet side, a plurality of ejectors, a receiver, and at least one compressor in the flow direction of the circulating refrigerant. Each of the plurality of ejectors has 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 rejection heat exchanger. The receiver includes an inlet, a liquid outlet, and a gas outlet. 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 rejection heat exchanger. The refrigeration evaporator flow path includes a liquid pump, at least one refrigeration expansion device, and at least one refrigeration 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. 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. The inlet side is in fluid communication with the outlet side of 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.

[0024] In one or more embodiments according to the present disclosure, the liquid pump includes a bypass line including a switchable bypass valve, and the switchable bypass valve is opened to allow the refrigerant to selectively bypass the liquid pump.

[0025] In order to further illustrate the advantages and features of the method, system and apparatus, a more particular description of the method, system and apparatus will be provided by reference to its specific embodiments 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 features and details in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] 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, in which like numerals represent like parts throughout the figures, and in which:

[0027] Figure 1A A schematic diagram exemplarily illustrates a system for controlling a plurality of ejectors in an ejector refrigeration circuit according to one or more embodiments of the present disclosure;

[0028] Figure 1B By way of example Figure 1A A schematic cross-sectional view of a controllable injector employed in an exemplary embodiment shown in FIG.

[0029] Figure 2 By way of example, Figure 1A A schematic diagram of multiple maps generated by a controller of the system shown in; and

[0030] Figure 3 A flow chart depicting a method for controlling a plurality of ejectors in an ejector refrigeration circuit is exemplarily shown.

[0031] Furthermore, the skilled artisan will recognize that the elements in the figures are shown for simplicity and may not necessarily be drawn to scale. For example, a flow chart illustrates a method in terms of the most prominent steps involved to help improve understanding of aspects of the present disclosure. Furthermore, with respect to the construction of a device, one or more components of the device may be represented in the figures with 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 those skilled in the art having the benefit of the description herein. DETAILED DESCRIPTION

[0032] To promote 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 the various embodiments. It will be understood, however, that no limitation of the scope of the present disclosure is thereby intended, and such changes and further modifications in the illustrated systems, and such further applications of the principles of the present disclosure as illustrated herein are contemplated as would normally occur to one skilled in the art to which the present disclosure relates.

[0033] It will be appreciated by those skilled in the art that both the foregoing general description and the following detailed description are illustrative of the present disclosure and are not intended to be restrictive thereof.

[0034] References throughout this specification to "aspect," "another aspect," or similar language mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the present disclosure. Thus, appearances of the phrases "in an 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.

[0035] 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 includes not only those steps but may also include other steps not expressly listed or inherent to such process or method. Similarly, one or more devices or subsystems or elements or structures or components beginning with "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 without more limitations.

[0036] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0037] FIG. 1 exemplarily shows a schematic diagram of a system 100 for controlling a plurality of ejectors 101 in an ejector refrigeration circuit according to one or more embodiments of the present disclosure.

[0038] In an exemplary embodiment according to the present disclosure, the ejector refrigeration circuit includes a high-pressure ejector circuit, which includes a heat rejection 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.

[0039] The heat rejection heat exchanger 105 includes an inlet side 105a and an outlet side 105b. The heat rejection heat exchanger 105 can also be interchangeably referred to as a gas cooler unit or a condenser. The heat rejection 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 rejection heat exchanger 105 may include one or more fans for blowing air through the heat rejection 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 cooling refrigerant leaving the heat rejection 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.

[0040] 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 rejection 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 of the receiver 106 and a gas phase portion collected in the upper portion of the receiver 106 by 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 portion 107a of at least one compressor 107, completing the refrigerant cycle of the high-pressure ejector circuit.

[0041] 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.

[0042] 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 force of gravity to be used to supply liquid refrigerant from the receiver 106 to the inlet side 108a of the liquid pump 108. The liquid pump 108 also includes a bypass line, which includes a switchable bypass valve 111, allowing 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.

[0043] 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.

[0044] The system 100 includes a controller 104 coupled to each of a plurality of ejectors 101 having a primary high pressure input port 101a, a secondary low pressure input port 101b, and an output port 101c. In an embodiment, each of the plurality of ejectors 101 is Figure 1B The controllable variable injector 101 disclosed in the detailed description of FIG. 8 is disclosed in the detailed description of FIG. 8 . Hereinafter, “injector 101 ” may be interchangeably referred to as “controllable variable injector 101 ”. In addition, a plurality of injectors 101 may be connected in parallel to each other or in a parallel configuration.

[0045] The plurality of injectors 101 may have different capacities, or may all have the same capacity. In another embodiment, a first group of injectors 101 from the plurality of injectors 101 may have equal capacities, and a second group of injectors 101 from the plurality of injectors 101 may have equal capacities, such that the capacity of the second group is greater than the capacity of the first group of injectors 101. In yet another embodiment, a first group of injectors 101 from the plurality of injectors 101 may have equal capacities, and a second group of injectors 101 from the plurality of injectors 101 may have equal capacities, such that the capacity of the first group is greater than the capacity of the second group of injectors 101.

[0046] If the plurality of injectors 101 used are controllable variable injectors 101, the plurality of injectors 101 may have a needle 126 ( Figure 1B As used herein, the term "opening percentage" is used to adjust the opening percentage. Figure 1B Detailed description of the invention is defined and described in detail in the detailed description of the invention. Alternatively, each of the multiple ejectors 101 used may be a controllable variable ejector 101, wherein the flow valve 112 is upstream of the secondary low pressure input port 101b. In an embodiment, the controller 104 is suitable for opening the flow valve 112 to allow the refrigerant to flow, and is suitable for closing the flow valve 112 to prevent the refrigerant from flowing. In such an implementation, the controller 104 actuates the flow valve 112 between the ON position and the OFF position to allow or prevent the refrigerant flow toward the secondary low pressure input port 101b of the corresponding ejector 101.

[0047] 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). The controller 104 is adapted to control the 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). Figure 2 The multiple ejectors 101 are controlled by the multiple generated maps described in detail in the detailed description of the ejector refrigeration circuit to increase the coefficient of performance (COP) of the ejector refrigeration circuit as efficiently as possible. In an embodiment, the controller 104 may refer to a single controller 104, or may be interpreted as including 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.

[0048] The controller 104 may further comprise 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 implementation 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.

[0049] 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 acoustics, radio frequency (RF), microwaves, infrared (IR), and other wireless media). In an embodiment, the computing device may be implemented as part of a small 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 specific application device, or a hybrid device including any of the above functions).

[0050] 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. Examples of suitable batteries include, for example, lithium batteries (such as lithium-ion batteries), nickel batteries (such as nickel-cadmium batteries), and alkaline batteries.

[0051] Figure 1B A schematic cross-sectional view of a controllable variable injector 101 is shown as an example (the controllable variable injector 101 can be Figure 1A101). Each of the plurality of ejectors 101 includes a main 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 main high-pressure input port 101a forms an inlet with respect to the power nozzle 113. The outlet of the external component 114 provides an output port 101c of the ejector 101. The main refrigerant flow 115 enters the main high-pressure input port 101a, and then enters the convergent section 116 of the power nozzle 113. Then, the main refrigerant flow 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 flow 115 and reduces the pressure of the main refrigerant flow 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 part 114. The outer part 114 includes a mixer having a convergent section 121 and an elongated throat or mixing section 122. The outer part 114 also has a divergent 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 convergent 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 122 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 merge at the outlet.

[0052] In operation, the primary refrigerant stream 115 may be supercritical when entering the controllable variable ejector 101 and subcritical when leaving the motive nozzle 113. The secondary stream 120 may be a gaseous state or a mixture of a gas and a smaller 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 in pressure in the diffuser 123 while maintaining mixing.

[0053] 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 end 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 adjust the entire controllable variable ejector 101. In an embodiment, each of the plurality of ejectors 101 may have a throat section 117 having different diameters. Alternatively, each of the plurality of ejectors 101 may have a throat section 117 having equal diameters. As used throughout this document, the term "opening percentage" refers to the opening percentage of the throat section 117. When the end portion 128 of the needle 126 moves into the throat section 117, the opening percentage is reduced to zero percent. Similarly, when the end portion 128 is completely moved 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 of 0-100%, such that an opening percentage of zero percent completely restricts the main refrigerant flow 115 , while an opening percentage of 100% fully allows the main refrigerant flow 115 .

[0054] In an embodiment, the actuator 127 may be an electric actuator, such as a solenoid or the like. Figure 1A The controller 104 disclosed in the detailed description of the can be connected to the actuator 127 and other controllable components of the controllable variable ejector 101 using hard wire or wireless communication paths. The controller 104 can store mathematical models to estimate the suction and motive flow rates. In this regard, 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 motive pressure, motive temperature, diameter of the ejector needle opening, diffuser pressure, suction pressure, etc. to dynamically estimate the suction flow rate and motive flow rate during operation.

[0055] Figure 2 By way of example, Figure 1A Schematic diagram of a plurality of maps 200, 200A, 200B, 200C generated by a controller 104 of the system 100 is shown in FIG. The controller 104 is coupled to each of the plurality of injectors 101 of the system 100. As an example, the controller 104 is shown to generate the maps 200, 200A, 200B, and 200C based on a set of predetermined conditions.

[0056] Each of the maps 200, 200A, 200B, 200C includes a plurality of phases 201, 202, 203. For example, in the first phase 201, only the first injector 101' is turned on. In the second phase 202, the first injector 101' and the second injector 101" are turned on. In the third phase 203, the first injector 101', the second injector 101" and the third injector 101"' are turned on. The number of phases 201, 202, 203 may be the same as the number of injectors 101. Figure 2 As shown in , in the illustrated embodiment, three stages 201, 202, 203 are depicted with respect to three injectors 101', 101", 101'". It can be appreciated that the number of injectors 101 can be two, three, more than three, or in extreme cases only one. In this regard, the number of stages can also include two stages, three stages, or in extreme cases a single stage. Therefore, the number of stages is equal to the number of injectors.

[0057] In an embodiment, the set of predetermined conditions may be a set of constraints, which at least include the following: (A) The opening percentages of the plurality of injectors 101 increase within a stage. This means that the opening percentages of the plurality of injectors 101 cannot decrease within a stage. (b) When switching between the multiple stages 201, 202, 203 of each of the multiple maps 200, 200A, 200B, 200C, the opening percentage of the multiple ejectors 101 is adjusted to keep the flow rate of the refrigerant fluid constant. This means that regardless of the number of ejectors 101 that are closed or opened, the cumulative refrigerant fluid leaving the multiple ejectors 101 can be kept constant. (c) when switching between the plurality of phases 201, 202, 203 of each of the plurality of maps 200, 200A, 200B, 200C, the opening percentage of the plurality of injectors 101 is greater than zero. This means that once an injector 101 from the plurality of injectors 101 is opened during any phase, the same injector 101 may not be closed in any subsequent phase; and (d) The flow rate of the refrigerant fluid passing through the secondary low-pressure input port 101 b of each of the plurality of ejectors 101 is greater than zero.

[0058] In an embodiment, each of the plurality of maps 200, 200A, 200B, 200C is associated with a corresponding temperature of the heat rejection heat exchanger 105. For example, the map 200 is generated for a temperature of 277.1K of the heat rejection heat exchanger 105, the map 200A is generated for a temperature of 289.1K of the heat rejection heat exchanger 105, the map 200B is generated for a temperature of 301.1K of the heat rejection heat exchanger 105, the map 200C is generated for a temperature of 313.1K of the heat rejection heat exchanger 105, etc. Each of the plurality of maps 200, 200A, 200B, 200C indicates a rate of change of a flow rate of the refrigerant fluid passing through each of the plurality of ejectors 101 based on a change in an opening percentage of each of the plurality of ejectors 101 during a corresponding temperature of the heat rejection heat exchanger 105.

[0059] Each of the plurality of maps 200, 200A, 200B, 200C comprises a plurality of phases 201, 202, 203. During the first phase 201, only the opening percentage of the first injector 101' is greater than zero. This means that the first injector 101' is open, while the second injector 101" and the third injector 101"' remain closed. During the second stage 202, the opening percentage of the plurality of injectors 101 other than the first injector 101' and the second injector 101" is equal to zero. This means that the first injector 101' and the second injector 101" are opened, while the third injector 101"' remains closed. Similarly, during the third stage 203, the opening percentage of the plurality of injectors 101 other than the first injector 101', the second injector 101", and the third injector 101"' is equal to zero. This means that the first injector 101', the second injector 101", and the third injector 101"' are opened, while any remaining injectors are closed. Therefore, in each of the maps 200, 200a, 200b, 200c, in each of the plurality of stages 201, 202, 203, the opening percentage of at least the first injector 101' from the plurality of injectors 101 is greater than zero.

[0060] As an example, when the temperature of the heat rejection heat exchanger 105 reaches 289.1K, the controller 104 identifies the first map 200A from the plurality of maps 200, 200A, 200B, 200C. The controller 104 also receives an input signal indicating the flow rate of the refrigerant fluid passing through the first ejector 101' from the first ejector 101'. The controller 104 adjusts the opening percentages of the plurality of ejectors 101 based on the identified first map 200A.

[0061] Figure 3 A flow chart is shown by way of example indicating a method 300 for controlling a plurality of ejectors 101 in an ejector refrigeration circuit. Figure 3The steps in the embodiment are shown and described in a particular order, but the steps may occur in a change in order according to various embodiments of the present disclosure. Figure 3 The details of each step (already covered in Figure 1A-2 A method 300 for controlling a plurality of ejectors in an ejector refrigeration circuit is disclosed.

[0062] At step 301, the controller 104 generates a Figure 2 1. Each of the multiple maps 200, 200A, 200B, 200C is associated with a corresponding temperature of the heat rejection heat exchanger 105. Generating multiple maps 200, 200A, 200B, 200C for different temperatures of the heat rejection heat exchanger 105 ensures that the ejector control is optimized over the entire operating range of the heat rejection heat exchanger 105.

[0063] At step 303, the controller 104 identifies a first map 200A from the plurality of maps 200, 200A, 200B, 200C that is associated with a first temperature of the heat rejection heat exchanger 105 and an input signal from the first ejector 101' that is indicative of a flow rate of the refrigerant fluid through the first ejector 101'. This feature advantageously allows the ejector control to be adjusted based on changes in the first temperature of the heat rejection heat exchanger 105. This means that any fluctuations or changes in the first temperature will not adversely affect the ejector control of the system 100.

[0064] At step 305 , the controller 104 adjusts the opening percentages of the plurality of injectors 101 based on the identified first map 200A.

[0065] The system 100 disclosed herein ensures that the overall machine behavior is more robust by minimizing the number of ON / OFF switches. This is because the set of predetermined conditions includes the constraint that the injector 101' opened in the first stage 201 cannot be closed in the subsequent stage 202 or 203. In addition, within the stage, the opening percentage of the injector 101 is always increased, thereby increasing the overall coefficient of performance (COP).

[0066] Although specific language is used to describe the subject matter, it is not intended to produce any limitation therefrom. As will be apparent to those skilled in the art, various work modifications may be made to the method in order to implement the creative conception as taught herein. The figures and the foregoing description provide 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, some elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment.

Claims

1. A system for controlling a plurality of ejectors 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; as well as a controller coupled to each of the plurality of injectors, the controller being adapted to: generating a plurality of maps based on a set of predetermined conditions, each of the plurality of maps being associated with a corresponding temperature of a heat rejection heat exchanger; identifying a first map from the plurality of maps that is associated with a first temperature of the heat rejection heat exchanger and an input signal indicative of a flow rate of a refrigerant fluid through a first ejector; as well as The opening percentages of the plurality of injectors are adjusted based on the identified first map.

2. The system according to claim 1, wherein: Each of the plurality of maps indicates a rate of change of the flow rate of the refrigerant fluid through each of the plurality of ejectors based on a change in the percentage of opening of each of the plurality of ejectors during the corresponding temperature of the heat rejection heat exchanger.

3. The system according to claim 1 or 2, wherein: Each of the plurality of maps includes a plurality of stages, and the opening percentage of at least the first injector from the plurality of injectors is greater than zero in each of the plurality of stages.

4. The system according to claim 3, wherein: The multiple stages include at least: A first stage, wherein the opening percentages of the plurality of injectors other than the first injector are equal to zero; a second stage, wherein the opening percentages of the plurality of injectors other than the first and second injectors are equal to zero; and The third stage, wherein the opening percentages of the plurality of injectors other than the first injector, the second injector, and the third injector are equal to zero.

5. A system according to any one of the preceding claims, wherein: The set of predetermined conditions includes: The opening percentages of the plurality of injectors are increased in stages; When switching between the plurality of stages of each of the plurality of maps, the opening percentages of the plurality of ejectors are adjusted to maintain the flow rate of the refrigerant fluid constant; When switching between the plurality of stages of each of the plurality of maps, the opening percentages of the plurality of injectors are greater than zero; and A flow rate of the refrigerant fluid passing through the secondary low pressure input port of each of the plurality of ejectors is greater than zero.

6. A system according to any one of the preceding claims, wherein: The plurality of injectors are controllable variable injectors connected in a parallel configuration.

7. A system according to any one of the preceding claims, wherein: The plurality of injectors have at least one of different capacities and equal capacities.

8. 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: The heat rejection heat exchanger has an inlet side and an outlet side; the plurality of ejectors, each of the plurality of ejectors having the primary high pressure input port, the secondary low pressure input port, and the output port, wherein the primary high pressure input port is in fluid communication with the 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 the 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 in the flow direction of the circulating refrigerant comprises: 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 sub-low pressure input port of each of the plurality of ejectors.

9. The system according to claim 8, wherein: The liquid pump includes a bypass line having a switchable bypass valve for allowing refrigerant to selectively bypass the liquid pump by opening the switchable bypass valve.

10. A method for controlling a plurality of ejectors in an ejector refrigeration circuit, the method comprising: generating, via a controller, a plurality of maps based on a set of predetermined conditions, each of the plurality of maps being associated with a corresponding temperature of a heat rejection heat exchanger; identifying, via the controller, from the plurality of maps, a first map associated with a first temperature of the heat rejection heat exchanger and an input signal indicative of a flow rate of a refrigerant fluid through a first ejector; as well as The opening percentages of the plurality of injectors are adjusted, via the controller, based on the identified first map.

11. The method according to claim 10, wherein: Each of the plurality of maps indicates a rate of change of the flow rate of the refrigerant fluid through each of the plurality of ejectors based on a change in the percentage of opening of each of the plurality of ejectors during the corresponding temperature of the heat rejection heat exchanger.

12. The method according to claim 10 or 11, wherein: Each of the plurality of maps includes a plurality of stages, and the opening percentage of at least the first injector from the plurality of injectors is greater than zero in each of the plurality of stages.

13. The method according to claim 12, wherein: The multiple stages include at least: A first stage, wherein the opening percentages of the plurality of injectors other than the first injector are equal to zero; a second stage, wherein the opening percentages of the plurality of injectors other than the first and second injectors are equal to zero; and The third stage, wherein the opening percentages of the plurality of injectors other than the first injector, the second injector, and the third injector are equal to zero.

14. The method according to any one of claims 10 to 13, wherein: The set of predetermined conditions includes: The opening percentages of the plurality of injectors are increased in stages; When switching between the plurality of stages of each of the plurality of maps, the opening percentages of the plurality of ejectors are adjusted to maintain the flow rate of the refrigerant fluid constant; When switching between the plurality of stages of each of the plurality of maps, the opening percentages of the plurality of injectors are greater than zero; and A flow rate of the refrigerant fluid passing through the secondary low pressure input port of each of the plurality of ejectors is greater than zero.

15. The method according to claim 10, wherein: Each of the plurality of ejectors includes a primary high pressure input port, a secondary low pressure input port, and an output port.

16. The method according to claims 10-15, wherein: Each of the plurality of injectors is a controllable variable injector connected in a parallel configuration.

17. The method according to claims 10-15, wherein: The plurality of injectors have at least one of different capacities and equal capacities.

18. The method according to claim 10, wherein: The ejector refrigeration circuit comprises: The high-pressure ejector circuit comprises, in the flow direction of the circulating refrigerant: The heat rejection heat exchanger has an inlet side and an outlet side; the plurality of ejectors, each of the plurality of ejectors having the primary high pressure input port, the secondary low pressure input port, and the output port, wherein the primary high pressure input port is in fluid communication with the 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 the 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 in the flow direction of the circulating refrigerant comprises: 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 sub-low pressure input port of each of the plurality of ejectors.

19. The method according to claim 10 or 18, 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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