Systems and methods for using variable geometry diffusers as check valves

Abstract

A compressor includes a diffuser passage configured to receive a refrigerant flow from an impeller of the compressor, wherein the diffuser passage is at least partially defined by a compressor discharge plate of the compressor. The compressor further includes a variable geometry diffuser positioned within the diffuser passage and configured to adjust the dimensions of a refrigerant flow path through the diffuser passage; an actuator coupled to the variable geometry diffuser and configured to adjust the position of the variable geometry diffuser within the diffuser passage; and a controller configured to regulate the operation of the actuator. The controller is configured to instruct the actuator to adjust the position of the variable geometry diffuser from a first position to a second position using a first force, and to adjust the position of the variable geometry diffuser from the second position to a third position using a second force less than the first force, wherein the variable geometry diffuser is adjacent to the compressor discharge plate in the third position.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit to U.S. Provisional Application No. 62 / 982,573, filed February 27, 2020, entitled “System and Method for Operation of Variable Geometry Diffusers Check Valve,” which is incorporated herein by reference in its entirety for all purposes. Background Technology

[0003] This application generally relates to vapor compression systems incorporated in air conditioning and refrigeration applications, and more specifically, to the flow control of refrigerant in a compressor.

[0004] This section aims to introduce the reader to various aspects of the art that may relate to the aspects of this disclosure described below. It is believed that this discussion will help provide the reader with background information to facilitate a better understanding of the aspects of this disclosure. Therefore, it should be understood that these statements should be read in this context and not as an endorsement of prior art.

[0005] Vapor compression systems are used in residential, commercial, and industrial environments to control environmental characteristics such as temperature and humidity for the occupants of those environments. Vapor compression systems circulate a working fluid, commonly referred to as a refrigerant, which changes phase between vapor, liquid, and combinations thereof in response to exposure to varying temperatures and pressures associated with the operation of the vapor compression system. For example, a vapor compression system utilizes a compressor to circulate refrigerant to a heat exchanger, which transfers heat between the refrigerant and another fluid flowing through it. Disadvantageously, in some cases, the refrigerant flow through the compressor can cause backspin, which can lead to unwanted wear and deterioration of the compressor and related components. Summary of the Invention

[0006] In embodiments of this disclosure, a compressor includes a diffuser passage configured to receive a refrigerant flow from the compressor impeller, wherein the diffuser passage is at least partially defined by a compressor discharge plate of the compressor. The compressor further includes a variable geometry diffuser located within the diffuser passage and configured to adjust the dimensions of a refrigerant flow path through the diffuser passage; an actuator coupled to the variable geometry diffuser and configured to adjust the position of the variable geometry diffuser within the diffuser passage; and a controller configured to regulate the operation of the actuator. The controller is configured to instruct the actuator to adjust the position of the variable geometry diffuser from a first position to a second position using a first force, and to adjust the position of the variable geometry diffuser from the second position to a third position using a second force less than the first force, wherein the variable geometry diffuser is adjacent to the compressor discharge plate in the third position.

[0007] In another embodiment of this disclosure, a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system includes a compressor configured to pressurize refrigerant in a refrigerant circuit, wherein the compressor includes a diffuser passage configured to receive the refrigerant from the compressor impeller. The HVAC&R system further includes a variable geometry diffuser of the compressor, wherein the variable geometry diffuser is configured to be located within the diffuser passage and configured to adjust the dimensions of a refrigerant flow path through the diffuser passage; an actuator configured to adjust the position of the variable geometry diffuser within the diffuser passage; and a controller configured to regulate the operation of the actuator, wherein the controller is configured to control the actuator to position the variable geometry diffuser within the diffuser passage and against the compressor discharge plate during compressor shutdown.

[0008] In another embodiment of this disclosure, a heating, ventilation, air conditioning and refrigeration (HVAC&R) system controller includes a tangible, non-transitory computer-readable medium storing computer-executable instructions that, when executed, are configured to cause a processing circuitry to: control an actuator to position a variable geometry diffuser within a first position range in the diffuser passage of the compressor during compressor operation; control the actuator to position the variable geometry diffuser within a second position range in the diffuser passage of the compressor during compressor shutdown; and control the actuator to maintain the position of the variable geometry diffuser within the diffuser passage and against the compressor discharge plate of the compressor during compressor shutdown. Attached Figure Description

[0009] A better understanding of various aspects of this disclosure can be achieved by reading the following detailed description and referring to the accompanying drawings, in which:

[0010] Figure 1 This is a perspective view of an embodiment of a building in a commercial environment that utilizes a heating, ventilation, air conditioning and cooling (HVAC&R) system, according to one aspect of this disclosure;

[0011] Figure 2 This is a perspective view of an embodiment of a vapor compression system according to one aspect of this disclosure;

[0012] Figure 3 This is a schematic diagram of an embodiment of a vapor compression system according to one aspect of the present disclosure;

[0013] Figure 4 This is a schematic diagram of an embodiment of a vapor compression system according to one aspect of the present disclosure;

[0014] Figure 5 This is a schematic diagram of an embodiment of a vapor compression system having multiple refrigerant circuits arranged in series in countercurrent flow, according to one aspect of this disclosure.

[0015] Figure 6 This is a cross-sectional view of an embodiment of a compressor having a variable geometry diffuser according to one aspect of this disclosure, the compressor being included in... Figure 1-5 In the system;

[0016] Figure 7 This is a schematic diagram of an embodiment of a variable geometry diffuser in a compressor according to one aspect of this disclosure; and

[0017] Figure 8 This is a schematic diagram of an embodiment of a control system for a variable geometry diffuser according to one aspect of this disclosure. Detailed Implementation

[0018] One or more specific embodiments of this disclosure will be described below. These described embodiments are examples of the technology currently disclosed. Additionally, in an effort to provide a concise description of these embodiments, not all features of an actual implementation may be described in the specification. It should be understood that in the development of any such actual implementation, as in any engineering or design project, many implementation-specific decisions must be made to achieve the developer's specific objectives, such as compliance with system-related and business-related constraints, which may vary from implementation to implementation. Furthermore, it should be understood that such development efforts can be complex and time-consuming, but remain routine tasks of design, assembly, and manufacture for those skilled in the art who benefit from this disclosure.

[0019] When describing elements of various embodiments of this disclosure, the articles “a,” “an,” and “the” are intended to indicate the presence of one or more elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that additional elements may be present in addition to those listed. Furthermore, it should be understood that references to “an embodiment” or “an embodiment” in this disclosure are not intended to be construed as excluding the existence of additional embodiments that also incorporate the described features.

[0020] Embodiments of this disclosure relate to heating, ventilation, air conditioning, and refrigeration (HVAC&R) systems configured to cool conditioning fluids. For example, an HVAC&R system may receive a flow of conditioning fluid, for instance, from an air handling unit or other terminal device in a building, and cool the conditioning fluid. The HVAC&R system may then return the conditioning fluid to the air handling unit for use in cooling or conditioning the air in the building. The HVAC&R system may include a vapor compression system configured to cool a refrigerant and place the cooled refrigerant in a heat exchange relationship with the conditioning fluid to absorb heat or thermal energy from the conditioning fluid. Generally, the vapor compression system includes a refrigerant circuit configured to circulate the refrigerant through one or more heat exchangers, such as condensers and evaporators. The vapor compression system also includes a compressor (e.g., a centrifugal compressor) for circulating the refrigerant through the refrigerant circuit. In some embodiments, the HVAC&R system is a cooler system, such as a water-cooled cooler system or an air-cooled cooler system.

[0021] Disadvantageously, in certain situations, the compressor may be prone to rotation (e.g., reverse rotation) due to the refrigerant flowing through the refrigerant circuit. For example, when the operation of the cooler system is suspended, conditioning fluid (e.g., water) may still flow through the evaporator and / or cooling fluid (e.g., water) may still flow through the condenser located along the refrigerant circuit. The temperature of the water may cause the refrigerant in the condenser to boil and / or cause the refrigerant in the evaporator to condense. Therefore, natural refrigerant migration may occur across the refrigerant circuit (e.g., from the condenser through the compressor to the evaporator), which may cause the compressor to rotate unintended (e.g., reverse rotation).

[0022] In embodiments of a cooler system having multiple refrigerant circuits (e.g., arranged in series counter-current) and therefore multiple compressors, the compressor may also be prone to rotation or reversal via the refrigerant flow when one of the refrigerant circuits is idle or not in operation. It should be understood that rotation or reversal of an inactive compressor can lead to wear and deterioration of the motor of the inactive compressor. Additionally, the bearing support system of the inactive compressor (e.g., oil pump, magnetic bearing, etc.) may also be inactive, thereby causing premature wear and deterioration of the inactive compressor and / or bearing support system when the compressor rotates or reverses. Disadvantageously, conventional systems and methods for reducing compressor rotation or reversal, such as automatic discharge isolation valves, are expensive.

[0023] Therefore, embodiments of this disclosure relate to systems and methods for using a variable geometry diffuser (VGD), such as a variable geometry diffuser ring, as a flow check valve to significantly reduce, block, or prevent unwanted refrigerant flow through the compressor and thereby mitigate compressor rotation and / or reversal. Specifically, this embodiment includes actuators and / or actuation systems (e.g., two-stage actuators) configured to operate in multiple modes to actuate and move the VGD within the diffuser passage of the compressor. For example, the actuator may be configured to operate in a first mode by applying a first force to move the VGD, and in a second mode by applying a second force less than the first force to move the VGD. According to the prior art, the control system is configured to selectively adjust the operation of the actuator between the first and second modes, for example, based on the compressor's operating state and / or based on the position of the VGD within the diffuser passage. The control system can operate the actuator in a first mode when the compressor is running, causing the VGD to move within the diffuser passage and adjust the size of the flow path (e.g., the refrigerant flow path) through the diffuser passage, for example, to control compressor surge or capacity. The control system can also operate the actuator in a second mode when the compressor is not operating during a fault process and / or a shutdown process, causing the VGD to move within the diffuser passage and abut against the opposing surface of the diffuser passage, thereby substantially completely blocking or sealing the flow path through the diffuser passage. In this way, the VGD can block or prevent the refrigerant flow through the compressor, thereby reducing compressor rotation and reversal when the compressor is not operating. The details of the operation of the control system and actuator are discussed further below.

[0024] It should be noted that the disclosure herein describes current technology used in conjunction with a VGD ring in a compressor. However, current technology can also be used in embodiments of compressors utilizing other types of VGDs, such as variable impeller diffusers, variable wall diffusers, or other types of diffusers. Furthermore, the following discussion describes current technology implemented in water-cooled cooler systems, but the systems and methods disclosed herein can also be implemented in other HVAC&R systems.

[0025] Now refer to the diagram. Figure 1 This is a perspective view of an embodiment of a heating, ventilation, air conditioning, and cooling (HVAC&R) system 10 in a building 12 for a typical commercial environment. The HVAC&R system 10 may include a vapor compression system 14 supplying a coolant that can be used to cool the building 12. The HVAC&R system 10 may also include a boiler 16 for supplying a heated liquid to heat the building 12, and an air distribution system for circulating air within the building 12. The air distribution system may also include return air ducts 18, supply air ducts 20, and / or air handlers 22. In some embodiments, the air handler 22 may include a heat exchanger connected to the boiler 16 and the vapor compression system 14 via ducts 24. Depending on the operating mode of the HVAC&R system 10, the heat exchanger in the air handler 22 may receive heated liquid from the boiler 16 or chilled liquid from the vapor compression system 14. The HVAC&R system 10 is shown with a separate air handler on each floor of the building 12, but in other embodiments, the HVAC&R system 10 may include the air handler 22 and / or other components that may be shared between floors.

[0026] Figure 2 and 3 An embodiment of a vapor compression system 14 that can be used in an HVAC&R system 10 is shown. The vapor compression system 14 allows refrigerant to circulate through a loop (e.g., a refrigerant loop) starting from the compressor 32. The loop may also include a condenser 34, an expansion valve or device 36, and a liquid cooler or evaporator 38. The vapor compression system 14 may further include a control panel 40 having an analog-to-digital (A / D) converter 42, a microprocessor 44, non-volatile memory 46, and / or an interface board 48.

[0027] Some examples of fluids that can be used as refrigerants in vapor compression system 14 include hydrofluorocarbon (HFC) based refrigerants such as R-410A, R-407, R-134a, hydrofluoroolefins (HFO); “natural” refrigerants such as ammonia (NH3), R-717, carbon dioxide (CO2), R-744; or hydrocarbon-based refrigerants, water vapor, or any other suitable refrigerant. In some embodiments, vapor compression system 14 may be configured to efficiently utilize a refrigerant having a normal boiling point of about 19 degrees Celsius (66 degrees Fahrenheit) at one atmosphere, also known as a low-pressure refrigerant, rather than a medium-pressure refrigerant such as R-134a. As used herein, “normal boiling point” can refer to the boiling point temperature measured at one atmosphere.

[0028] In some embodiments, the vapor compression system 14 may use one or more of a variable speed drive (VSD) 52, an electric motor 50, a compressor 32, a condenser 34, an expansion valve or device 36, and / or an evaporator 38. The electric motor 50 may drive the compressor 32 and may be powered by the variable speed drive (VSD) 52. The VSD 52 receives AC power with a specific fixed line voltage and fixed line frequency from an alternating current (AC) power source and supplies power with a variable voltage and variable frequency to the electric motor 50. In other embodiments, the electric motor 50 may be directly powered by an AC or direct current (DC) power source. The electric motor 50 may comprise any type of motor that can be powered by a VSD or directly from an AC or DC power source, such as a switched reluctance motor, an induction motor, an electronically commutated permanent magnet motor, or another suitable motor.

[0029] Compressor 32 compresses refrigerant vapor and delivers it to condenser 34 through a discharge passage. In some embodiments, compressor 32 may be a centrifugal compressor. The refrigerant vapor delivered by compressor 32 to condenser 34 can transfer heat to a cooling fluid (e.g., water or air) in condenser 34. As a result of heat transfer with the cooling fluid, the refrigerant vapor can condense into liquid refrigerant in condenser 34. The liquid refrigerant from condenser 34 can flow through expansion device 36 to evaporator 38. Figure 3 In the illustrated embodiment, the condenser 34 is water-cooled and includes a tube bundle 54 connected to a cooling tower 56, which supplies cooling fluid to the condenser 34.

[0030] The liquid refrigerant supplied to evaporator 38 can absorb heat from another cooling fluid (e.g., a regulating fluid), which may or may not be the same cooling fluid used in condenser 34. The liquid refrigerant in evaporator 38 can undergo a phase change from liquid refrigerant to refrigerant vapor. Figure 3As illustrated in the described embodiment, the evaporator 38 may include a tube bundle 58 having a supply line 60S and a return line 60R connected to the cooling load 62. A conditioning fluid (e.g., water, ethylene glycol, calcium chloride brine, sodium chloride brine, or any other suitable fluid) enters the evaporator 38 via the return line 60R and exits the evaporator 38 via the supply line 60S. The evaporator 38 can reduce the temperature of the conditioning fluid in the tube bundle 58 through heat transfer with the refrigerant. The tube bundle 58 in the evaporator 38 may include multiple tubes and / or multiple tube bundles. In any case, vaporized refrigerant exits the evaporator 38 and returns to the compressor 32 via the suction line to complete the cycle.

[0031] Figure 4 This is a schematic diagram of an embodiment of a vapor compression system 14 having an intermediate loop 64 incorporated between the condenser 34 and the expansion unit 36. The intermediate loop 64 may have an inlet line 68 directly fluidly connected to the condenser 34. In other embodiments, the inlet line 68 may be indirectly fluidly connected to the condenser 34. Figure 4 As shown in the illustrated embodiment, the inlet line 68 includes a first expansion device 66 located upstream of the intermediate container 70. In some embodiments, the intermediate container 70 may be a flash tank (e.g., a flash intercooler). In other embodiments, the intermediate container 70 may be configured as a "heat exchanger" or a "surface energy saver". Figure 4 In the illustrated embodiment, intermediate container 70 serves as a flash tank, and first expansion device 66 is configured to reduce (e.g., expand) the pressure of liquid refrigerant received from condenser 34. During expansion, a portion of the liquid may evaporate, so intermediate container 70 can be used to separate the vapor from the liquid received from first expansion device 66. Additionally, intermediate container 70 can provide further expansion of the liquid refrigerant due to the pressure drop experienced by the liquid refrigerant upon entering intermediate container 70 (e.g., due to the rapid increase in volume experienced upon entering intermediate container 70). Vapor in intermediate container 70 can be drawn by compressor 32 through suction line 74 of compressor 32. In other embodiments, vapor in intermediate container 70 can be drawn into intermediate stage (e.g., non-suction stage) of compressor 32. Due to expansion in expansion device 66 and / or intermediate container 70, liquid collected in intermediate container 70 may have a lower enthalpy than liquid refrigerant leaving condenser 34. Liquid from intermediate container 70 can then flow in line 72 through second expansion device 36 to evaporator 38.

[0032] As mentioned above, the systems and methods disclosed herein can be used in HVAC&R system 10 and / or vapor compression system 14 having multiple refrigerant loops. For example, Figure 5This is a schematic diagram of an embodiment of a vapor compression system 14 having multiple refrigerant circuits 80 (e.g., refrigerant loops). Specifically, the illustrated embodiment includes a first refrigerant circuit 82 and a second refrigerant circuit 84 arranged in a series countercurrent arrangement. The first refrigerant circuit 82 includes a first compressor 32A, a first condenser 34A, a first expansion device 36A, and a first evaporator 38A. The second refrigerant circuit 84 includes a second compressor 32B, a second condenser 34B, a second expansion device 36B, and a second evaporator 38B. Each of the refrigerant circuits 80 is configured to circulate a corresponding refrigerant through it, and is configured to operate in a manner similar to the above reference. Figure 2-4 The vapor compression system 14 shown operates in the manner described. It should be noted that each of the refrigerant circuits 80 may also include, in addition to... Figure 2-4 Components other than those shown.

[0033] In the illustrated embodiment, the first refrigerant circuit 82 and the second refrigerant circuit 84 of the vapor compression system 14 are arranged in a series countercurrent configuration. Specifically, the first evaporator 38A and the second evaporator 38B define a portion of a regulating fluid flow path or circuit 86 extending from a cooling load 88 (e.g., air handler 22), sequentially passing through the second evaporator 38B and the first evaporator 38A, and returning to the cooling load 88. Similarly, the first condenser 34A and the second condenser 34B define a portion of a cooling fluid flow path or circuit 90 extending from a cooling fluid source 92 (e.g., cooling tower 56), sequentially passing through the first condenser 34A and the second condenser 34B, and returning to the cooling fluid source 92. Therefore, the regulating fluid is directed through the vapor compression system 14, first through the second evaporator 38B, and then through the first evaporator 38A, while the cooling fluid is directed through the vapor compression system 14, first through the first condenser 34A, and then through the second condenser 34B, thereby providing a series countercurrent arrangement.

[0034] In some cases, one of the refrigerant circuits 80 may be operational while the other may be inactive. It should be understood that the compressor 32 of the inactive refrigerant circuit 80 may be idle (e.g., the motor 50 associated with the compressor 32 is not powered). Therefore, the compressor 32 of the inactive refrigerant circuit 80 is not operational, allowing refrigerant to circulate through the inactive refrigerant circuit 80. However, natural refrigerant migration may still occur in the inactive refrigerant circuit 80. For example, if the first refrigerant circuit 82 is operational and the second refrigerant circuit 84 is inactive, cooling fluid may still circulate along the cooling fluid circuit 90 through the second condenser 34B (e.g., starting from the first condenser 34A, through the second condenser 34B, and reaching the cooling fluid source 92). Similarly, conditioning fluid may still circulate along the conditioning fluid circuit 86 through the second evaporator 38B (e.g., starting from the cooling load 88, through the second evaporator 38B, and reaching the first evaporator 38A). In some cases, the flow of cooling fluid through the second condenser 34B and / or the flow of regulating fluid through the second evaporator 38B can cause spontaneous refrigerant migration through the second refrigerant circuit 84. As discussed above, spontaneous refrigerant migration may cause unintended rotation or reversal in the non-operational second compressor 32B.

[0035] Therefore, this embodiment includes a flow control system 94 configured to improve the operation and control of the compressor 32, for example by reducing, blocking, and / or preventing unwanted rotation and / or reversal of the compressor 32. As described in further detail below, the flow control system 94 may be combined (e.g., integrated) with the compressor 32 (e.g., one or both of compressors 32A, 32B) and may include a variable geometry diffuser (VGD) of the compressor 32, an actuation system configured to adjust the position of the VGD within the compressor 32, and a control system configured to control the operation of the actuation system. In some applications, the VGD is used to adjust the flow path through the diffuser passage of the compressor 32 to control the surge and / or capacity of the compressor 32 during operation. Additionally, the VGD can be controlled via an actuation system and a control system to position it within the diffuser passage, thereby completely or substantially completely blocking the flow path through the diffuser passage by positioning the VGD against the opposing wall of the diffuser passage, and thus blocking the refrigerant flow through the diffuser passage when the compressor 32 is not operating. In this way, the VGD can act as a flow check valve to mitigate or reduce the rotation and / or reversal of the compressor 32 that may occur due to natural refrigerant migration when the compressor 32 is not operating. As discussed in further detail below, the actuation system is configured to move the VGD within the diffuser passage using a first force for capacity and / or surge control, and to move the VGD within the diffuser passage using a second force less than the first force to abut against the opposing surface and completely block the flow path through the diffuser passage.

[0036] Figure 6 A cross-section of an embodiment of compressor 32, which may be included in a reference. Figure 1-5 This can be included in any of the described systems or in any other suitable HVAC&R system 10. The refrigerant flow path 100 is shown through the compressor 32, where the refrigerant travels through the blades 102 of the impeller 104 of the compressor 32 toward a diffuser passage 106 defined by a nozzle base plate 109 (e.g., compressor housing) and a compressor discharge plate 116 (e.g., diffuser plate) and extending between the nozzle base plate and the compressor discharge plate. The refrigerant is guided from the diffuser passage 106 to a collector 108 (e.g., a volute). The blades 102 of the impeller 104 rotate (e.g., via operation of the electric motor 50) to accelerate the refrigerant outward from the center of rotation of the impeller 104. The accelerated refrigerant can travel along the refrigerant flow path 100 shown toward the diffuser passage 106, which is designed to convert the kinetic energy of the refrigerant into pressure, for example, by gradually reducing the refrigerant velocity.

[0037] As described above, the compressor 32 may include a flow control system 94 for regulating the refrigerant flow through the compressor 32. The flow control system 94 may include a variable geometry diffuser (VGD) 110, an actuator 112, and a controller 114 (e.g., a control system) disposed in or near the lower portion of the diffuser passage 106 (e.g., between and near the impeller 104 and collector 108). For example, the VGD 110 may be at least partially located within or near the nozzle base plate 109 (e.g., within a recess formed in the nozzle base plate). In the illustrated embodiment, the VGD 110 is a VGD ring. However, in other embodiments, the VGD 110 may be a variable blade diffuser, a variable wall diffuser, or other types of variable diffuser. The position of the VGD 110 within the diffuser passage 106 is adjustable to improve the control and operation of the compressor 32. For example, VGD 110 may be coupled to actuator 112 (e.g., a two-stage actuator, an actuation system, etc.), which, upon instruction from controller 114 (e.g., a control system), actuates VGD 110 from a previous position or moves it to a desired position. In some embodiments, actuator 112 may be an electromechanical actuator, a magnetic actuator, a hydraulic actuator, or any other suitable type of actuator. As described herein, flow control system 94 (e.g., actuator 112 and / or controller 114) is configured to operate in two or more stages or modes. For example, actuator 112 may actuate VGD 110 in a first stage or mode (e.g., a high torque mode) by applying a first force to VGD 110, and actuate VGD 110 in a second stage or mode (e.g., a low torque mode) by applying a second force less than the first force to VGD 110.

[0038] Controller 114 can control the position of VGD 110 such that VGD 110 adjusts the size of the flow path through diffuser passage 106. For example, controller 114 can control the operation of actuator 112 to increase or decrease the size of the flow path through diffuser passage 106 (e.g., refrigerant flow path 100) without completely blocking the flow path through diffuser passage 106 during operation of compressor 32 (e.g., to control surge and / or capacity of compressor 32). Controller 114 can also control the operation of actuator 112 to position VGD 110 within the entire diffuser passage 106 such that VGD 110 is adjacent to compressor discharge plate 116 of compressor 32 (e.g., diffuser plate), thereby completely blocking diffuser passage 106 and preventing refrigerant flow through said diffuser passage. In this way, VGD 110 is used as a flow check valve to alleviate or prevent (e.g., impeller 100) rotation and / or reversal, for example, during periods when compressor 32 is not operating or is stopped.

[0039] Controller 114 may include processing circuitry 118 and memory 120. Memory 120 may contain tangible, non-transitory computer-readable medium that stores instructions that, when executed by processing circuitry 118, cause processing circuitry 118 to perform the various functions or operations described herein. For this purpose, processing circuitry 118 may be any suitable type of computer processor or microprocessor capable of executing computer-executable code, including, but not limited to, one or more field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), programmable logic devices (PLDs), programmable circuit arrays (PLAs), etc. For example, controller 114 may control the operating capacity of compressor 32 at least in part based on certain operating and / or environmental conditions (e.g., refrigerant temperature). Controller 114 may also include data stored in memory 120 indicating the desired position of VGD 110 based on the operating capacity of compressor 32. Furthermore, controller 114 may be configured to control the stage or actuation force of actuator 112 based on the position of VGD 110 within diffuser channel 106 and / or based on the operating state of compressor 32. For example, when VGD 110 is within a first position range within diffuser channel 106, controller 114 can control actuator 112 to adjust the position of VGD 110 using a first force or torque, and when VGD 110 is within a second position range within diffuser channel 106, the controller can control the actuator to adjust the position of VGD using a second force or torque less than the first force or torque. The control of VGD 110 via actuator 112 and controller 114 is described in further detail below.

[0040] Figure 7 yes Figure 6 A cross-sectional view of an embodiment of compressor 32, wherein VGD 110 is in a partially blocked position. Figure 6 and 7 As shown, the VGD 110 is typically configured to travel along direction 130 (e.g., axis) within the diffuser channel 106, and as Figure 7 As shown, a portion of the diffuser passage 106 (e.g., a flow path) can be defined as a width 132 (e.g., a dimension) smaller than the total width 134 (e.g., a dimension) of the diffuser passage 106. As discussed, the actuator 112 is configured to actuate and move the VGD 110 within the diffuser passage 106 to, for example, adjust the size of the width 132 of the diffuser passage 106 through which refrigerant can flow. In some embodiments, the actuator 112 may be coupled to the VGD 110 via a link 136 (e.g., a mechanical link) configured to transmit the force applied by the actuator 112 to the VGD 110.

[0041] In the illustrated embodiment, VGD 110 is shown at the origin or "zero" position 138. For example, the starting position 138 of VGD 110 could be a threshold position (e.g., a lower threshold position) within the diffuser passage 106 beyond which the actuator 112 and / or controller 114 will not adjust VGD 110 during the operating period of the compressor 32 (e.g., the VGD moves further into the diffuser passage 106 and / or further toward the compressor discharge plate 116). In other words, when the compressor 32 is operating, the actuator 112 and / or controller 114 are configured to move VGD 110 within a first position range 140 in the diffuser passage 106 and not to place VGD 110 outside the starting position 138 (e.g., closer to the compressor discharge plate 116). Therefore, when the compressor 32 is operating, a gap 142 is maintained between the distal surface 144 of the VGD 110 and the compressor discharge plate 116, wherein the dimension (e.g., width) of the gap 142 from the distal surface 144 to the compressor discharge plate 116 is greater than or equal to Figure 7 The width 132 is shown in the diagram. It should be understood that the presence of gap 142 allows for thermal growth of VGD 110 and prevents contact between VGD 110 and compressor discharge plate 116 during operation of compressor 32, which would otherwise result in unwanted force transmission to linkage 136 or other components of compressor 32.

[0042] According to this embodiment, actuator 112 and / or controller 114 are also configured to selectively move VGD 110 beyond the starting position 138 and into contact with the compressor discharge plate 116. For example, during a shutdown of compressor 32 (e.g., a period of inactivity, a fault process, and / or a shutdown process), controller 114 may instruct actuator 112 to move VGD 110 beyond the starting position 138 (e.g., further away from nozzle base plate 109) such that VGD 110 contacts compressor discharge plate 116 to block (e.g., completely block) discharge passage 106 and thereby block or prevent refrigerant flow through discharge passage 106. In other words, during a period of inactivity of compressor 32, a fault process, and / or a shutdown process, controller 114 may instruct actuator 112 to move VGD 110 within a second position range 146 such that VGD 110 is located beyond the starting position 128 (e.g., relative to nozzle base plate 109). Figure 7As shown, the first position range 140 and the second position range 146 may extend cooperatively across the total width 134 of the diffuser passage 106 (e.g., equal to the total width). In some embodiments, the first position range 140 and the second position range 146 do not overlap each other and are separated by a starting position 138. By positioning the VGD 110 within the second position range 146 (e.g., adjacent to the compressor discharge plate 116), the VGD 110 can function as a flow check valve, which prevents the natural migration of refrigerant through the compressor 32 that might occur when the compressor 32 is not operating (e.g., migration from the condenser 34 to the evaporator 38 and / or migration along direction 148).

[0043] As mentioned above, the flow control system 94 (e.g., actuator 112) is configured to operate in two or more modes or levels. In a first mode or level, the controller 114 can control the actuator 112 to adjust the position of the VGD 110 by applying a first force or torque (e.g., a large force and / or a force above a threshold amount) to the VGD 110, and in a second mode or level, the controller 114 can control the actuator 112 to adjust the position of the VGD 110 by applying a second force or torque less than the first force or torque (e.g., a smaller force and / or a force below a threshold amount) to the VGD 110. For example, the controller 114 can be configured to instruct the actuator 112 to operate in the first mode or level when the VGD 110 is within a first position range 140, and to instruct the actuator 112 to operate in the second mode or level when the VGD 110 is within a second position range 146. By moving VGD 110 within a first position range 140 using a first force or a larger force when compressor 32 is operating, the position of VGD 110 can be quickly and efficiently adjusted during compressor 32 operation to control surge and / or capacity. By moving VGD 110 within a second position range 146 using a second force or a smaller force when compressor 32 is not operating, VGD 110 can be positioned to contact compressor discharge plate 116 and thus block natural refrigerant migration through diffuser passage 106, while preventing unwanted forces from being transmitted to VGD 110, linkage 136, actuator 112, or other components of compressor 32.

[0044] As an example, compressor 32 can operate with VGD 110 positioned within diffuser passage 106 within a first position range 140, and controller 114 can receive indications (e.g., feedback) of compressor 32 malfunction or shutdown (e.g., from control panel 40). For this purpose, controller 114 can be communicatively coupled to other control components of the vapor compression system 14 and / or the regulation system operation of HVAC&R system 10. Based on these indications, controller 114 can instruct actuator 112 to adjust the position of VGD 110 to a starting position 138 in a first mode or stage of actuator 112 (e.g., using a first force or a larger force). Once VGD 110 reaches the starting position 138, controller 114 can instruct actuator 112 to adjust the position of VGD 110 from the starting position 138 to a position contacting compressor discharge plate 116 in a second mode or stage of actuator 112 (e.g., using a second force or a smaller force). As further discussed below, once VGD 110 is in full contact with the compressor discharge plate 116, the controller 116 can instruct the actuator 112 to maintain the position of VGD 110 against the compressor discharge plate 116 to block or prevent the flow of refrigerant through the discharge passage 106. For example, the actuator 112 can maintain the position of VGD 110 in contact with the compressor discharge plate 116 until the controller 114 (e.g., from the control board 40) receives a command to operate the compressor 32 or to unblock the diffuser passage 106.

[0045] Figure 8 This is a schematic diagram of a flow control system 94 that includes a controller 114, an actuator 112, and a VGD 110, and illustrates additional features that can be combined with systems utilizing the disclosed technology. For example, the actuator 112 includes a sensor 150 and a locking system 152. The sensor 150 is configured to detect operating parameters of the actuator 112 and can transmit feedback indicating these operating parameters to the controller 114. For example, in one embodiment, the actuator 112 may be an electromechanical motor, and the sensor 150 may be configured to detect torque acting on the motor (e.g., on the shaft of the motor coupled to the VGD 110). The controller 114 may refer to the torque feedback from the sensor 150 to determine when the VGD 110 is positioned to make sufficient contact with the compressor discharge plate 116 to block the refrigerant flow through the discharge passage 106. As discussed above, the controller 114 may also be configured to receive inputs and / or feedback from other components (e.g., control panel 40) and may operate the actuator 112 based on said feedback. In some embodiments, inputs and / or feedback may indicate the operating mode or capacity of compressor 32, vapor compression system 14 and / or HVAC&R system 10.

[0046] When controller 114 determines that VGD 110 is positioned in full contact with compressor discharge plate 116 (e.g., based on feedback from sensor 150), controller 114 may instruct actuator 112 to activate locking system 152 to maintain the position of VGD 110 within diffuser channel 106, and may interrupt operation of actuator 112 to move VGD 110. In some embodiments, locking system 152 may include a mechanical locking system configured to maintain the position of actuator 112 and VGD 110. The mechanical locking system may include, for example, a mechanical interlocking device, a key, a pin, a conical ring, a spring lock, a braking mechanism, a piston, another suitable locking device, or any combination thereof. In some embodiments, locking system 152 may include an electrically locking system configured to block power supply to actuator 112 and thereby maintain the position of actuator 112 and VGD 110. Other embodiments of the locking system 152 may include additional or alternative components, such as pneumatic locks, hydraulic locks, magnetic locks, electromechanical locks, or any combination thereof.

[0047] It should be understood that, according to embodiments of the prior art, additional and / or alternative sensors 150 configured to provide feedback to controller 114 may be utilized. For example, flow control system 94 may include sensors 150 for implementing the functionality described above, such as position sensors, current sensors, temperature sensors, pressure sensors, flow rate sensors, contact sensors, or other sensors. In some embodiments, one or more sensors 150 may be coupled to other components of vapor compression system 14 and / or located along refrigerant circuit 80 or at other locations within the refrigerant circuit.

[0048] As discussed above, embodiments of this disclosure relate to systems and methods for using a variable geometry diffuser (VGD) as a flow check valve in a compressor to significantly reduce, block, or prevent unwanted refrigerant flow through the compressor and thereby mitigate compressor rotation and / or reversal. Embodiments include an actuator configured to operate in multiple modes to actuate and move the VGD within the diffuser passage of the compressor, and the operating mode may be based on the compressor's operating state and / or the position of the VGD within the diffuser passage. The actuator may operate in a first mode while the compressor is operating to move the VGD within the diffuser passage and adjust the size of the flow path through the diffuser passage, for example, to control compressor surge or capacity. The control system may enable the actuator to operate in a second mode when the compressor is not operating to move the VGD within the diffuser passage and abut against the opposite surface of the diffuser passage, thereby substantially completely blocking or sealing the flow path through the diffuser passage. Therefore, the disclosed systems and methods enable the use of VGD to block or prevent the flow of refrigerant through the compressor in order to reduce compressor rotation and / or reverse it when the compressor is not operating.

[0049] Although only certain features and embodiments of this disclosure are illustrated and described, many modifications and variations will occur to those skilled in the art without substantially departing from the novel teachings and advantages of the subject matter set forth in the claims, such as variations in the size, dimensions, structure, shape and proportions of the various elements, parameter values ​​(including temperature and pressure), installation arrangements, use of materials, color, orientation, etc. The order or sequence of any process or method steps may be varied or rearranged according to alternative embodiments. Therefore, it should be understood that the appended claims are intended to cover all such modifications and changes as falling within the true spirit of this disclosure. Furthermore, for the purpose of providing a concise description of exemplary embodiments, not all features of actual embodiments may be described, such as those not relevant to the best mode of carrying out this disclosure as currently considered prudent, or those not relevant to achieving the disclosure required. It should be noted that in the development of any such actual embodiments, as in any engineering or design project, many implementation-specific decisions may be made. Such development work may be complex and time-consuming, but it remains routine for those skilled in the art who benefit from this disclosure to design, manufacture, and process without excessive experimentation.

[0050] The techniques proposed and claimed herein are referenced and applied to practical objects and specific instances of a material nature, which demonstrably improve the technical field, and are therefore not abstract, intangible, or purely theoretical. Furthermore, if any claim appended to this specification contains one or more elements expressed as "a component for [performing] [the function]..." or "a step for [performing] [the function]...", such elements are expected to be interpreted in accordance with 35U.SC112(f). However, for any claim containing elements specified in any other way, these elements should not be interpreted in accordance with 35U.SC112(f).

Claims

1. A compressor comprising: A diffuser passage configured to receive a refrigerant flow from the impeller of the compressor, wherein the diffuser passage is at least partially defined by the compressor discharge plate of the compressor; A variable geometry diffuser, located within the diffuser passage and configured to adjust the dimensions of the refrigerant flow path through the diffuser passage; An actuator, the actuator being coupled to the variable geometry diffuser and configured to adjust the position of the variable geometry diffuser within the diffuser channel; as well as A controller configured to regulate the operation of the actuator, wherein the controller is configured to instruct the actuator during operation of the compressor to position the variable geometry diffuser within a first position range in the diffuser passage, the first position range including a lower threshold position, and the size of the refrigerant flow path through the diffuser passage when the variable geometry diffuser is at the lower threshold position corresponds to the lower threshold size of the refrigerant flow path during operation of the compressor; and The controller is configured to instruct the actuator to use a first force to adjust the position of the variable geometry diffuser from a first position to the lower threshold position, and to use a second force less than the first force to adjust the position of the variable geometry diffuser from the lower threshold position to a second position, wherein the variable geometry diffuser is adjacent to the compressor discharge plate in the second position.

2. The compressor of claim 1, wherein the controller is configured to instruct the actuator to use the first force to adjust the position of the variable geometry diffuser within the first position range in the diffuser passage, the first position being within the first position range of the variable geometry diffuser, and the dimension of the refrigerant flow path through the diffuser passage when the variable geometry diffuser is in the first position is greater than the lower threshold dimension.

3. The compressor of claim 2, wherein the controller is configured to instruct the actuator to adjust the position of the variable geometry diffuser within the first position range based on the capacity of the compressor.

4. The compressor of claim 1, wherein the controller is configured to, based on a signal received by the controller instructing the actuator to use the second force to adjust the position of the variable geometry diffuser from the lower threshold position to the second position.

5. The compressor of claim 1, wherein the actuator includes a sensor configured to provide feedback to the controller indicating that the variable geometry diffuser is in the second position.

6. The compressor of claim 5, wherein the actuator is an electric motor, and the sensor is a torque sensor configured to detect torque acting on the electric motor.

7. The compressor of claim 1, wherein the variable geometry diffuser is configured to completely block the refrigerant flow through the compressor in the second position.

8. The compressor according to claim 1, wherein the variable geometry diffuser is a variable geometry diffuser ring.

9. The compressor of claim 1, wherein the actuator includes a locking system configured to hold the variable geometry diffuser in the second position during a pause operation of the compressor.

10. A heating, ventilation, air conditioning and cooling system, comprising: A compressor configured to pressurize refrigerant in a refrigerant circuit, wherein the compressor includes a diffuser passage configured to receive the refrigerant from the impeller of the compressor; The compressor has a variable geometry diffuser, wherein the variable geometry diffuser is configured to be located within the diffuser passage and configured to adjust the size of the refrigerant flow path through the diffuser passage; An actuator configured to adjust the position of the variable geometry diffuser within the diffuser channel; as well as A controller configured to regulate the operation of the actuator, wherein the controller is configured to instruct the actuator during operation of the compressor to position the variable geometry diffuser within a first position range within the diffuser passage, the first position range including a lower threshold position, and the dimension of the refrigerant flow path through the diffuser passage when the variable geometry diffuser is at the lower threshold position corresponds to the lower threshold dimension of the refrigerant flow path during operation of the compressor; and The controller is configured to reduce the first force applied by the actuator during the shutdown of the compressor before the variable geometry diffuser contacts the compressor discharge plate, so that the variable geometry diffuser is positioned against the compressor discharge plate.

11. The heating, ventilation, air conditioning, and refrigeration system of claim 10, wherein the controller is configured to instruct the actuator to position the variable geometry diffuser against the compressor discharge plate based on an indication of compressor shutdown or compressor failure received by the controller.

12. The heating, ventilation, air conditioning, and refrigeration system of claim 10, wherein the controller is configured to instruct the actuator to position the variable geometry diffuser within a second position range in the diffuser channel during a stop of the compressor.

13. The heating, ventilation, air conditioning and cooling system of claim 12, wherein the first position range and the second position range do not overlap with each other.

14. The heating, ventilation, air conditioning, and refrigeration system of claim 10, wherein the controller is configured to instruct the actuator to position the variable geometry diffuser within the first position range in the diffuser channel to control the surge of the compressor and / or control the capacity of the compressor.

15. The heating, ventilation, air conditioning, and refrigeration system of claim 12, wherein the controller is configured to instruct the actuator to use the first force to position the variable geometry diffuser within the first position range, the controller is configured to instruct the actuator to use a second force to position the variable geometry diffuser within the second position range, and the second force is less than the first force.

16. The heating, ventilation, air conditioning, and refrigeration system of claim 10, comprising a first refrigerant circuit and a second refrigerant circuit, wherein the first refrigerant circuit includes the compressor, the first refrigerant circuit and the second refrigerant circuit are each configured to exchange heat with a cooling fluid flow, the first refrigerant circuit and the second refrigerant circuit are each configured to exchange heat with a regulating fluid flow, and the first refrigerant circuit and the second refrigerant circuit are arranged in a series countercurrent configuration relative to the cooling fluid flow and the regulating fluid flow.

17. A controller for a heating, ventilation, air conditioning, and refrigeration system, comprising a tangible, non-transitory computer-readable medium, the computer-readable medium including computer-executable instructions, which, when executed, are configured to cause the processing circuitry system to: The control actuator positions the variable geometry diffuser within a first position range in the diffuser passage of the compressor during operation of the compressor, wherein the first position range includes a lower threshold position, and the size of the refrigerant flow path through the diffuser passage when the variable geometry diffuser is at the lower threshold position corresponds to the lower threshold size of the refrigerant flow path during operation of the compressor. The actuator is controlled to position the variable geometry diffuser within a second position range in the diffuser passage of the compressor during the compressor's shutdown period; The actuator is controlled to maintain the position of the variable geometry diffuser within the diffuser passage and against the compressor discharge plate during the shutdown of the compressor; The sensor receives feedback indicating the torque applied to the actuator; and Based on the feedback control, the actuator is positioned so that the variable geometry diffuser is positioned against the compressor discharge plate of the compressor.

18. The heating, ventilation, air conditioning, and refrigeration system controller of claim 17, wherein the computer-executable instructions, when executed, are configured to cause the processing circuitry system to: The actuator is controlled to apply a first force to the variable geometry diffuser so that the variable geometry diffuser is positioned within the first position range in the diffuser passage of the compressor; and The actuator is controlled to apply a second force to the variable geometry diffuser so that the variable geometry diffuser is located within the second position range in the diffuser passage of the compressor. The first force is greater than the second force.

19. The heating, ventilation, air conditioning and refrigeration system controller of claim 17, wherein the computer-executable instructions, when executed, are configured to cause the processing circuitry system to activate the actuator locking system to maintain the position of the variable geometry diffuser within the diffuser passage and abutting the compressor discharge plate of the compressor during compressor shutdown.

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