Bearing system for HVACR system

Abstract

A heating, ventilation, air conditioning and refrigeration (HVACamp; R) system includes a compressor configured to circulate a working fluid along a working fluid circuit; a bearing disposed around a shaft of the compressor; and a fluid supply system configured to direct a portion of the working fluid from the working fluid circuit to the bearing, where the bearing is configured to discharge the portion of the working fluid toward the shaft.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 443,921, filed February 7, 2023, entitled “BEARING SYSTEM FOR HVAC&R SYSTEM,” which is incorporated herein by reference in its entirety for all purposes. Background Art

[0002] This section is intended to introduce the reader to various technical aspects that may be relevant to the various aspects of the present disclosure described below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Therefore, it should be understood that these statements should be read in this light, and not as admissions of prior art.

[0003] Chiller systems, or vapor compression systems, utilize a working fluid (e.g., a refrigerant) that changes phase between vapor, liquid, and combinations thereof in response to exposure to varying temperatures and pressures within the components of the chiller system. Chiller systems can place the working fluid in heat exchange relationship with a conditioning fluid (e.g., water) and deliver the cooling fluid to conditioning equipment and / or the conditioned environment served by the chiller system. In such applications, the conditioning fluid can be directed through downstream equipment, such as an air handler, to condition other fluids, such as the air in a building. The chiller system can include a compressor configured to pressurize the working fluid and circulate it through the chiller system's working fluid circuit. In some applications, the compressor's shaft can be rotated by an electric motor to drive the rotation of the compressor's impeller, which pressurizes the working fluid. Traditionally, compressors include bearings configured to facilitate the rotation of the shaft. Unfortunately, existing bearings used with compressors can be complex, expensive, and / or can result in inefficiencies in the operation of the chiller system. Summary of the Invention

[0004] The following describes an overview of certain embodiments disclosed herein. It should be understood that these aspects are presented merely to provide the reader with a brief overview of these certain embodiments and are not intended to limit the scope of the present disclosure. In fact, the present disclosure may encompass a variety of aspects that may not be described below.

[0005] In one embodiment, a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system includes a compressor configured to circulate a working fluid along a working fluid circuit; a bearing disposed about a shaft of the compressor; and a fluid supply system configured to direct a portion of the working fluid from the working fluid circuit to the bearing, wherein the bearing is configured to discharge the portion of the working fluid toward the shaft.

[0006] In another embodiment, a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system includes a working fluid circuit having a compressor, an evaporator, and a condenser, wherein the compressor is configured to circulate a working fluid along the working fluid circuit. The HVAC&R system also includes a bearing assembly for the compressor, wherein the bearing assembly is disposed around a shaft of the compressor, the bearing assembly includes a plurality of radial bearing segments arranged around a circumference of the shaft, and each of the plurality of radial bearing segments includes a porous material. The HVAC&R system further includes a fluid supply circuit extending from the working fluid circuit to the bearing assembly, wherein the fluid supply circuit is configured to direct a flow of working fluid from the working fluid circuit to the bearing assembly.

[0007] In another embodiment, a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system includes a bearing configured to be positioned around a shaft of a compressor, wherein the bearing includes a porous material and is configured to discharge a fluid flow through the porous material and toward the shaft of the compressor. The HVAC&R system also includes a fluid supply system configured to direct the fluid flow from a working fluid circuit of the HVAC&R system to the bearing, wherein the fluid supply system is configured to supply the fluid flow to the bearing in a liquid phase, and the bearing is configured to discharge the fluid flow toward the shaft in a vapor phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Various aspects of the present disclosure may be better understood after reading the following detailed description and referring to the accompanying drawings, in which: Figure 1 is a perspective view of an embodiment of a building that may utilize a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system in a commercial setting according to aspects of the present disclosure; Figure 2 is a perspective view of an embodiment of a vapor compression system according to aspects of the present disclosure; Figure 3 is a schematic diagram of an embodiment of a vapor compression system according to aspects of the present disclosure; Figure 4 is a schematic diagram of an embodiment of a vapor compression system according to aspects of the present disclosure; Figure 5 is a cross-sectional side view of an embodiment of a compressor of a vapor compression system according to aspects of the present disclosure, illustrating a bearing system of the compressor; Figure 6 is an axial view of a portion of an embodiment of a compressor including a bearing system for the compressor according to aspects of the present disclosure; Figure 7 is a schematic diagram of an embodiment of a bearing assembly of a bearing system for a compressor according to aspects of the present disclosure; Figure 8 is a schematic diagram of an embodiment of a vapor compression system including a fluid supply system and a bearing system for a compressor according to aspects of the present disclosure; Figure 9 is a schematic diagram of an embodiment of a vapor compression system including a fluid supply system and a bearing system for a compressor according to aspects of the present disclosure; Figure 10 is a partial cross-sectional side view of an embodiment of a bearing for a bearing system for a compressor according to aspects of the present disclosure; and Figure 11 is a partial cross-sectional side view of an embodiment of a bearing for a bearing system for a compressor according to aspects of the present disclosure. DETAILED DESCRIPTION

[0009] One or more specific embodiments are described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in this specification. It should be understood that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developer's specific goals, such as complying with system-related and business-related constraints, which may vary between implementations. Furthermore, it should be understood that such development work can be complex and time-consuming, but can nevertheless be a routine task of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

[0010] When introducing elements of various embodiments of the present disclosure, the articles "a," "an," and "said" are intended to mean that there are one or more of the recited elements. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements. Furthermore, it should be understood that references to "one embodiment" or "an embodiment" of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

[0011] As used herein, as will be understood by one of ordinary skill, the terms "substantially," "generally," and "substantially," etc., are intended to convey that the value of a property being described may be within a relatively small range of property values. For example, when a property value is described as being "substantially" equal to (or, for example, "substantially similar to") a given value, this is intended to mean that the property value may be within + / - 5%, + / - 4%, + / - 3%, + / - 2%, + / - 1%, or even closer to the given value. Similarly, when a given feature is described as being "substantially parallel" to another feature, "substantially perpendicular" to another feature, etc., this is intended to mean that the given feature is within + / - 5%, + / - 4%, + / - 3%, + / - 2%, + / - 1%, or even closer to having the described property (e.g., parallel to another feature, perpendicular to another feature, etc.). Furthermore, it should be understood that mathematical terms such as "flat," "sloped," "perpendicular," "parallel," and the like are intended to encompass characteristics of a surface or element as understood by one of ordinary skill in the art and should not be rigidly construed as being understood mathematically. For example, a "flat" surface is intended to encompass a surface that is machined, molded, or otherwise formed to be generally flat or smooth (within relevant tolerances) using techniques and tools available to one of ordinary skill in the art. Similarly, a surface having a "slope" is intended to encompass a surface that is machined, molded, or otherwise formed to be oriented at an angle (e.g., tilted) relative to a reference point using techniques and tools available to one of ordinary skill in the art.

[0012] Embodiments of the present disclosure relate to a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system (e.g., a chiller) that includes a vapor compression system (e.g., a vapor compression circuit) with a compressor. During operation, the compressor can pressurize a working fluid within the vapor compression system and direct the working fluid to a condenser (e.g., a first heat exchanger), which can cool and condense the working fluid. The condensed working fluid can be directed to an expansion device, which can reduce the pressure of the working fluid, thereby further cooling the working fluid. From the expansion device, the cooled working fluid can be directed to an evaporator (e.g., a second heat exchanger), where the working fluid can enter into heat exchange relationship with a conditioning fluid to cool the conditioning fluid. The conditioning fluid can circulate between the evaporator and a structure, such as a building, where it is used to cool an air flow delivered to a conditioned space in the structure. In some embodiments, an air handling unit (AHU) of the HVAC&R system can receive the conditioning fluid from the chiller and use it to cool the air flow delivered to the conditioned space. The conditioning fluid can then be returned to the evaporator for further cooling.

[0013] In some embodiments, a compressor may include an impeller configured to rotate to pressurize a working fluid and direct the working fluid through the vapor compression system. For example, the impeller may be coupled to a shaft, and the shaft may be configured to rotate relative to the compressor's housing to drive the impeller's rotation relative to the housing. Typically, the compressor includes one or more bearings configured to facilitate rotation of the shaft relative to the compressor's housing. Unfortunately, existing bearings used in compressors are susceptible to numerous drawbacks. For example, existing bearings may include sleeves, roller elements, or other bearing surfaces lubricated by specialized lubricants (e.g., oil). The use of oil within a vapor compression system can reduce the efficiency of heat transfer between the working fluid and other fluids (e.g., conditioning fluid) circulating through the system. Furthermore, systems with oil-lubricated bearings typically include complex subsystems and oil return systems to manage proper lubrication of the bearings. Magnetic bearings may also be utilized with compressors. However, magnetic bearings are complex, expensive, and utilize complex control systems. Therefore, there is a need for improved compressor bearings that are lower in cost and enable more efficient operation of vapor compression systems.

[0014] Therefore, embodiments of the present invention are directed to a bearing system configured to enable and facilitate operation of a compressor in a vapor compression system with improved efficiency and reduced cost. Specifically, the bearing system described herein is configured to utilize a pressurized fluid, such as a working fluid (e.g., refrigerant) circulated through the vapor compression system, to support the load of a compressor shaft and enable rotation of the shaft within the compressor's housing. The pressurized fluid can also serve as a lubricant. To this end, the bearing system includes one or more bearings having porous bearing elements configured to receive the pressurized fluid. The pressurized fluid (e.g., liquid) can be directed through the porous bearing elements and discharged to contact the shaft within the housing. As the pressurized fluid is directed through and discharged from the porous bearing elements, it can vaporize or "flash-boil" to become a vapor or gas that contacts the shaft and forms a hydrostatic film around the shaft. In this way, the working fluid that circulates through the vapor compression system to exchange heat with other fluids (e.g., a conditioning fluid supplied to the load) can also serve as a lubricant to achieve the desired operation of the compressor. In fact, embodiments of the present invention enable the incorporation of bearings within a compressor without utilizing a separate, dedicated lubricant (e.g., oil). The disclosed embodiments of the bearing system can also be implemented at reduced costs (e.g., manufacturing costs, operating costs, maintenance costs) compared to conventional bearings. Furthermore, the techniques discussed herein enable the incorporation and operation of the bearing system within a compressor with simplified control schemes, improved reliability, and required monitoring.

[0015] Now turning to the diagram, Figure 1A perspective view of an embodiment of a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system 10 in a building 12 in a typical commercial setting is shown. The HVAC&R system may include a vapor compression system 14 for supplying a cooling fluid to cool the building 12 and a boiler 16 for supplying a warm fluid to heat the building 12. The vapor compression system 14 (also referred to herein as a chiller) may circulate a working fluid (e.g., a refrigerant) that is cooled by a cooling fluid (e.g., a liquid such as water) in a condenser of the vapor compression system 14 and heated by a conditioning fluid (e.g., a liquid such as water) in an evaporator of the vapor compression system 14. The cooling fluid may be provided by a cooling tower that cools the cooling fluid via, for example, ambient air. The conditioning fluid, cooled by the working fluid as mentioned above, may be used to cool the air flow provided to the conditioned spaces of the building 12.

[0016] The HVAC&R system 10 may also include an air distribution system that circulates air through the building 12. The air distribution system may also include air return ducts 18, air supply ducts 20, and / or air handlers 22. In some embodiments, the air handlers 22 may include heat exchangers connected to the boiler 16 and the vapor compression system 14 by ducting 24. Depending on the operating mode of the HVAC&R system 10, the heat exchangers in the air handlers 22 may receive heated liquid from the boiler 16 or conditioning fluid (e.g., a cooled liquid such as water) 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 air handlers 22 and / or other components that may be shared between or among floors.

[0017] Figure 2 and Figure 3 An embodiment of a vapor compression system 14 or chiller that can be used in an HVAC&R system 10 is described. The vapor compression system 14 can circulate a working fluid through a working fluid circuit (e.g., a refrigerant circuit) beginning with a compressor 32 (e.g., a centrifugal compressor). The circuit can also include a condenser 34, one or more expansion valves or devices 36, and an evaporator 38. The vapor compression system 14 can further include a control panel 40 having an analog-to-digital (A / D) converter 42, a microprocessor 44, nonvolatile memory 46, and / or an interface board 48.

[0018] Some examples of fluids that can be used as the working fluid in vapor compression system 14 are hydrofluorocarbon (HFC) refrigerants, such as R-410A, R-407, R-134a, hydrofluoroolefins (HFOs); "natural" refrigerants, such as ammonia (NH3), R-717, carbon dioxide (CO2), R-744; or hydrocarbon refrigerants; water vapor; or any other suitable working fluid. Other possible working fluids include R-123, R-514A, R-1224yd, R-1233zd, R-134a, R-1234ze, R-1234yf, R-1142ze, R-1142yf, R-1311, R-32, and R-410A. In some embodiments, vapor compression system 14 can be configured to efficiently utilize a working fluid having a normal boiling point of approximately 19 degrees Celsius (66 degrees Fahrenheit) at one atmosphere of pressure, which is also referred to as a low-pressure working fluid relative to a medium-pressure working fluid (e.g., R-134a). As used herein, "normal boiling point" can refer to the boiling point temperature measured at one atmosphere of pressure.

[0019] In some embodiments, the vapor compression system 14 may utilize one or more of a variable speed drive (VSD) 52, an electric motor 50, the compressor 32, the condenser 34, the expansion valve or device 36, and / or the evaporator 38. The electric motor 50 may drive the compressor 32 during a normal operating mode and may be powered by the variable speed drive (VSD) 52. The VSD 52 receives alternating current (AC) power during a normal operating mode, wherein the AC power comprises a specific fixed line voltage and a fixed line frequency from an AC power source, and provides power having a variable voltage and frequency to the electric motor 50. In other embodiments, the electric motor 50 may be powered directly from an AC or direct current (DC) power source. The electric motor 50 may include any type of electric 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 electric motor.

[0020] Compressor 32 compresses the working fluid vapor and delivers the vapor to condenser 34 through an exhaust passage. In some embodiments, compressor 32 may be a centrifugal compressor. The working fluid vapor delivered to condenser 34 by compressor 32 may transfer heat to a cooling fluid (e.g., water or air) in condenser 34. Due to the heat transfer with the cooling fluid, the working fluid vapor may condense into working fluid liquid in condenser 34. The liquid working fluid from condenser 34 may flow through expansion device 36 to evaporator 38. Figure 3 In the illustrated embodiment of , the condenser 34 is water-cooled and includes a tube bundle 54 connected to a cooling tower 56 that supplies cooling fluid to the condenser 34 .

[0021] The liquid working fluid delivered to the evaporator 38 may absorb heat from the conditioning fluid, which is then delivered to the load 62 (eg, Figure 1 The conditioning fluid may be cooled by the working fluid in the evaporator 38 and then used to Figure 1 The liquid working fluid in the evaporator 38 may undergo a phase change from a liquid working fluid to a working fluid vapor. Figure 3 As shown in the illustrated embodiment of FIG, the evaporator 38 may include a tube bundle 58 having a supply line 60S and a return line 60R connected to a cooling load 62. The conditioning fluid of the evaporator 38 (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 may reduce the temperature of the conditioning fluid in the tube bundle 58 through heat transfer with the working fluid. The tube bundle 58 in the evaporator 38 may include multiple tubes and / or multiple tube bundles. In any case, the vapor working fluid exits the evaporator 38 and returns to the compressor 32 through the suction line to complete the cycle.

[0022] Figure 4 FIG. 1 is a schematic diagram of an embodiment of vapor compression system 14 in which intermediate loop 64 is incorporated between condenser 34 and expansion device 36. Intermediate loop 64 may have an inlet line 68 that is directly fluidly connected to condenser 34. In other embodiments, inlet line 68 may be indirectly fluidly coupled to condenser 34. Figure 4 In the illustrated embodiment shown in FIG, the inlet line 68 includes a first expansion device 66 positioned upstream of an intermediate vessel 70. In some embodiments, the intermediate vessel 70 may be a flash evaporation tank (e.g., a flash evaporative intercooler). In other embodiments, the intermediate vessel 70 may be configured as a heat exchanger or a "surface economizer." Figure 4In the illustrated embodiment, the intermediate vessel 70 serves as a flash evaporation tank, and the first expansion device 66 is configured to reduce the pressure of (e.g., expand) the liquid working fluid received from the condenser 34. During the expansion process, a portion of the liquid working fluid may vaporize, and thus, the intermediate vessel 70 may be used to separate the vapor working fluid from the liquid working fluid received from the first expansion device 66. Additionally, the intermediate vessel 70 may provide further expansion of the liquid working fluid due to the pressure drop experienced by the liquid working fluid upon entering the intermediate vessel 70 (e.g., due to the rapid increase in volume experienced upon entering the intermediate vessel 70). The vapor working fluid in the intermediate vessel 70 may be drawn by the compressor 32 via the suction line 74 of the compressor 32. In other embodiments, the vapor working fluid in the intermediate vessel 70 may be drawn into an intermediate section of the compressor 32 (e.g., rather than the suction section). Due to the expansion of the working fluid at the expansion device 66 and / or in the intermediate vessel 70, the liquid working fluid collected in the intermediate vessel 70 may have a lower enthalpy than the liquid working fluid exiting the condenser 34. The liquid working fluid from the intermediate vessel 70 may then flow through line 72 and through the second expansion device 36 to the evaporator 38 .

[0023] According to embodiments of the present invention, the compressor 32 may be a centrifugal compressor (e.g., a hermetic compressor) having a suspended rotor or shaft. To this end, the vapor compression system 14 includes a bearing system having one or more bearings configured to support the load of the shaft of the compressor 32. The bearing system is configured to direct a pressurized fluid (e.g., a liquid) through the bearings, and the bearings are configured to discharge the fluid toward and against the shaft to achieve suspension of the shaft within the compressor 32. Specifically, the bearings include one or more porous bearing elements configured to receive the pressurized fluid and direct it toward the shaft within the housing of the compressor 32. In this manner, the bearing system can support the load on the shaft and enable rotation of the shaft within the housing of the compressor 32 during operation of the vapor compression system 14. As discussed herein, the pressurized fluid can be a working fluid (e.g., a refrigerant) circulated through the vapor compression system 14 (e.g., through a working fluid circuit of the vapor compression system 14). Thus, the vapor compression system 14 may not utilize a specialized lubricant, such as oil, to support and rotate the shaft of the compressor 32. Furthermore, the bearing system may be integrated with the vapor compression system 14 at a reduced cost compared to other existing bearing system designs. As further described below, the disclosed embodiments also enable improved (e.g., simplified) control of the bearing system and more efficient operation of the vapor compression system 14.

[0024] Taking the foregoing into account, Figure 5FIG2 is a cross-sectional side view of an embodiment of a compressor 32 including a bearing system 100 according to aspects of the present disclosure. The compressor 32 may include a housing 102 and a shaft 104 extending through the housing 102. The compressor 32 may also include an impeller 106 coupled to the shaft 104, for example, via a fastener 108. During operation of the compressor 32, the shaft 104 may rotate (e.g., via operation of the motor 50) and cause the impeller 106 to rotate. The rotation of the impeller 106 may drive a working fluid (e.g., a refrigerant) through a working fluid flow path 110 (e.g., a working fluid circuit, from the evaporator 38, from the intermediate reservoir 70) to draw the working fluid into the housing 102 via a suction inlet 112 and toward the impeller 106. The impeller 106 may impart mechanical energy to the working fluid and discharge the working fluid into a diffuser passage 114 of the compressor 32. The working fluid may be channeled from diffuser passage 114 to spiral chamber 116 of compressor 32 and from spiral chamber 116 to a condenser (eg, condenser 34 ) for heat exchange with a fluid, such as a cooling fluid.

[0025] In the illustrated embodiment, the compressor 32 (e.g., the bearing system 100) includes a first bearing 118 (e.g., a radial bearing, a bearing assembly, a porous bearing) and a second bearing 120 (e.g., a radial bearing, a bearing assembly, a porous bearing) configured to control and / or adjust the position (e.g., radial position) of the shaft 104 relative to an axis 122 (e.g., an axis of rotation, a central axis) of the shaft 104. For example, the first bearing 118 and the second bearing 120 can be configured to support a load (e.g., a radial load) on the shaft 104 such that the shaft 104 is suspended within the first bearing 118 and the second bearing 120 (e.g., within the housing 102). The first bearing 118 and the second bearing 120 can also be configured to block movement of the shaft 104 transverse to the axis 122 (e.g., bending, radial movement, eccentric rotation). The compressor 32 (e.g., the bearing system 100) further includes a third bearing 124 (e.g., a thrust bearing, an axial bearing, a bearing assembly, a porous bearing) configured to control and / or adjust the position (e.g., axial position) of the shaft 104 along the axis 122. For example, the third bearing 124 can be configured to block or limit movement (e.g., translation) of the shaft 104 along the axis 122.

[0026] As mentioned above, the bearing system 100 is configured to direct a pressurized fluid to the bearings of the bearing system 100, such as the first bearing 118, the second bearing 120, and / or the third bearing 124. The pressurized fluid may be the same working fluid (e.g., refrigerant) that circulates through the vapor compression system 14 having the compressor 32. However, it should be understood that the pressurized fluid may be any suitable fluid, such as a refrigerant, a condensable vapor, or other fluid. In some embodiments, the first bearing 118, the second bearing 120, and / or the third bearing 124 each include one or more porous elements 126 configured to direct the pressurized fluid therethrough. For example, the one or more porous elements 126 of the first bearing 118 and the second bearing 120 may be configured to receive the pressurized fluid and direct it toward the shaft 104 to establish a high-pressure fluid film (e.g., a vapor film) around the shaft 104 between the first bearing 118 and the second bearing 120 and the shaft 104. In this manner, the pressurized fluid can cause the shaft 104 to levitate from the first bearing 118 and the second bearing 120, thereby enabling the desired rotation of the shaft 104 about the axis 122. The one or more porous elements 126 of the third bearing 124 can receive the pressurized fluid and direct the pressurized fluid toward a collar 128 (e.g., a thrust collar) of the third bearing 124. In this manner, the pressurized fluid can apply a force to the collar 128 and enable adjustable positioning of the shaft 104 along the axis 122.

[0027] The bearing system 100 includes a fluid supply system 130 configured to supply pressurized fluid to the bearings of the bearing system 100 (e.g., the first bearing 118, the second bearing 120, and / or the third bearing 124). For example, the fluid supply system 130 may direct the pressurized fluid through the housing 102 of the compressor 32 to one or more bearing housings 132 (e.g., casings) of the first bearing 118, the second bearing 120, and the third bearing 124. In the illustrated embodiment, one bearing housing 132 is associated with the first bearing 118, and another bearing housing 132 is associated with the second bearing 120. Additional bearing housings 132 may be utilized with the third bearing 124. In other embodiments, the second bearing 120 and the third bearing 124 may be housed together in a common bearing housing 132. The pressurized fluid may be directed through the bearing housings 132 to a corresponding porous element 126 retained within each bearing housing 132. The fluid supply system 130 is described in more detail below. It should be appreciated that the compressor 32 may include any suitable number or type (eg, radial, axial) of bearings incorporating the present teachings, and that the bearings may be positioned at any suitable location within the casing 102 of the compressor 32 .

[0028] Figure 6FIG2 is an axial view of a portion of an embodiment of a compressor 32 including a bearing assembly 150 (e.g., a bearing, a radial bearing) according to aspects of the present disclosure. For example, the bearing assembly 150 may be an embodiment of the first bearing 118 or the second bearing 120 discussed above. In other words, the bearing assembly 150 is a radial bearing assembly configured to support (e.g., suspend) the shaft 104 within the housing 102 of the compressor 32. The bearing assembly 150 includes a bearing housing 132 and a radial bearing 152 (e.g., a bearing portion, a bearing segment, a radial bearing element) configured to be coupled to the bearing housing 132. In some embodiments, the radial bearing 152 may be described as a bearing segment, a bearing portion, or a bearing section, and the radial bearing 152 may cooperatively form or define a radial bearing (e.g., the bearing assembly 150) of the compressor 32. It should be noted that the illustrated embodiment includes four radial bearings 152 (eg, bearing segments), but the bearing assembly 150 may include any suitable number of radial bearings 152 , such as two, three, five, six, or more radial bearings 152 (eg, arranged around the circumference of the shaft 104 ).

[0029] The radial bearing 152 includes a base portion 154 and a pad portion 156 coupled to the base portion 154. The radial bearing 152 is configured to be structurally coupled to the bearing housing 132 via a mounting portion 158 of the bearing housing 132. For example, the mounting portion 158 may be a post having threads, a pin, or other suitable features to enable adjustable positioning of the radial bearing 152 relative to the bearing housing 132 (e.g., radial position relative to the axis 122). The mounting portion 158 may also enable adjustable positioning of the radial bearing 152 relative to the axis 122 and the shaft 104, which may enable the radial bearing 152 to be assembled with the shaft 104 in a preloaded (e.g., contacting) arrangement. Thus, when the bearing system 100 is not in operation, the pad portion 156 of one or more of the radial bearings 152 may be in contact with the shaft 104 (e.g., via the force of gravity on the shaft 104).

[0030] The base portion 154 of the radial bearing 152 can be formed from any suitable material, such as a metal material. The base portion 154 also includes a cavity 160 (e.g., an internal volume) formed therein. The cavity 160 is configured to receive a pressurized fluid flow from the fluid supply system 130. To this end, the bearing assembly 150 also includes one or more transfer conduits 162 (e.g., fluid conduits, fluid transfer conduits) configured to fluidically couple the bearing housing 132 to the cavity 160 of the radial bearing 152. For example, in some embodiments, the bearing assembly 150 may include multiple transfer conduits 162, each of which may be fluidically coupled to one of the cavities 160 of the radial bearing 152. In the assembled configuration, the transfer conduits 162 may extend (e.g., be screwed into) the base portion 154. The transfer conduits 162 may also extend (e.g., be screwed into) the mounting portion 158. For example, the mounting portion 158 may also define ports to fluidly couple channels or conduits within the bearing housing 132 to the transfer conduits 162. Thus, for each radial bearing 152 (e.g., bearing segment), a portion of the pressurized fluid flow directed into the bearing housing 132 may flow through the bearing housing 132, through the mounting portion 158, through the transfer conduits 162, and into the cavity 160 of the base portion 154.

[0031] Cavity 160 of base portion 154 is fluidically coupled to and / or exposed to gasket portion 156. In accordance with the present technology, gasket portion 156 is formed from a porous material. In other words, the porous material of gasket portion 156 may define a plurality of passages or channels through which fluid may flow. In some embodiments, gasket portion 156 is formed from a metallic material, such as carbon, graphite, sintered metal, and / or a matrix of metallic material. Gasket portion 156 may also have a profile or geometry corresponding to the profile or geometry of shaft 104. When pressurized fluid is supplied to cavity 160, the pressurized fluid may be forced through the porous material of gasket portion 156 and may be discharged from gasket portion 156 toward axis 122 and / or shaft 104, as indicated by arrow 164. As described in more detail below, the channels defined by the porous material of gasket portion 156 may be sized to allow the pressurized fluid (e.g., pressurized liquid) to vaporize or instantaneously evaporate, causing the fluid to be discharged from radial bearing 152 in the form of vapor or gas. In this manner, the gaseous fluid may form a high-pressure film between the radial bearing 152 and the shaft 104 and enable the shaft 104 to be levitated from the radial bearing 152. Additionally, during operation of the compressor 32, and therefore during rotation of the shaft 104, the high-pressure film between the radial bearing 152 and the shaft 104 may facilitate rotation of the shaft 104 with reduced friction, improved efficiency, and the like.

[0032] Figure 7A schematic diagram of a portion of an embodiment of a bearing assembly 150 (e.g., radial bearing 152) illustrates a pad portion 156 formed from a porous material, such as a porous metal material (e.g., carbon). The illustrated embodiment also includes a mounting portion 180 coupled to and extending from the base portion 154. The mounting portion 180 can be configured to enable mounting of the radial bearing 152 to the bearing housing 132 of the bearing assembly 150. In other embodiments, the pad portion 156 can be a component of the third bearing 124 (e.g., a thrust bearing) discussed above. As similarly described above, the base portion 154 defines a cavity 160 configured to receive a pressurized fluid flow from the fluid supply system 130. In other embodiments, the bearing assembly 150 may not include the base portion 154 and may include the pad portion 156 having the cavity 160 formed therein.

[0033] Additionally, a fluid supply port 182 extends from base portion 154. Fluid supply port 182 is configured to receive a flow of pressurized fluid from fluid supply system 130 and direct the pressurized fluid into cavity 160. For example, fluid supply port 182 may be fluidly coupled to a conduit extending through bearing housing 132 and / or housing 102 of compressor 32. As similarly discussed above, pressurized fluid (e.g., liquid) within cavity 160 may be forced through the porous material of liner portion 156 and may be expelled (e.g., in the form of vapor or gas) from a radially inward surface 185 (e.g., a surface facing shaft 104) of liner portion 156 toward guide surface 184, as indicated by arrow 186. For example, guide surface 184 may be a surface of shaft 104 disposed within (e.g., radially inward of) first bearing 118 and / or second bearing 120, or guide surface 184 may be a surface of collar 128 of third bearing 124. The fluid (e.g., gas, vapor) exhausted from the pad portion 156 can create a film 188 (e.g., a gas hydrostatic film, a high-pressure vapor film) between the pad portion 156 and the guide surface 184, which enables relative movement (e.g., rotation) between the pad portion 156 and the guide surface 184. The high pressure of the film 188 can also enable the shaft 104 to be suspended within the bearing assembly 150 having the radial bearings 152 (e.g., radially within the bearing assembly 150 having the radial bearings 152). In fact, because the radial bearings 152 can be arranged around the circumference of the shaft 104, the film 188 can be created by the radial bearings 152 to achieve centering of the shaft 104 within the bearing assembly 150, so that the shaft 104 is radially offset from each of the radial bearings 152.

[0034] Figure 8FIG2 is a schematic diagram of an embodiment of a vapor compression system 14 (e.g., an HVAC&R system) that includes a bearing system 100 for a compressor 32. The vapor compression system 14 includes elements similar to those discussed above, including the compressor 32, the electric motor 50, the condenser 34, and the evaporator 38 (e.g., a falling film evaporator) arranged along a working fluid circuit 200 (e.g., a refrigerant circuit). In accordance with the present technology, the bearing system 100 also includes a fluid supply system 130 configured to direct pressurized fluid to the bearings of the bearing system 100 (e.g., the bearing assembly 150). In particular, the fluid supply system 130 is configured to direct a portion of the working fluid circulating through the working fluid circuit 200 to the bearing assembly 150. To this end, the fluid supply system 130 includes a lubricant circuit 202 (e.g., a fluid supply circuit) that extends from the working fluid circuit 200 to the bearing assembly 150 (e.g., to the radial bearing 152).

[0035] In the illustrated embodiment, the lubricant circuit 202 extends from a liquid line portion 204 of the working fluid circuit 200 to the bearing assembly 150. The liquid line portion 204 extends from the condenser 34 to the evaporator 38. Therefore, the working fluid within the liquid line portion 204 can be in a liquid phase. Various components are positioned along the lubricant circuit 202 and configured to enable the working fluid to be desirably supplied to the bearing assembly 150, thereby enabling the bearing assembly 150 to support the load of the shaft 104 of the compressor 32. For example, the fluid supply system 130 includes a pump 206 (e.g., a liquid pump) positioned along the lubricant circuit 202 and configured to direct a flow of working fluid (e.g., liquid working fluid) along the lubricant circuit 202 from the liquid line portion 204 of the working fluid circuit 200 to the bearing assembly 150 of the motor 50 (e.g., the compressor 32). In some embodiments, the pump 206 can be a linear piston pump, and the pump 206 can be driven electrically, pneumatically, mechanically, electromechanically, and / or via another suitable technology. In some embodiments, the pump 206 can operate without utilizing oil or other specialized lubricants.

[0036] The fluid supply system 130 also includes an accumulator 208 fluidly coupled to the lubricant circuit 202. The accumulator 208 is fluidly coupled to the lubricant circuit 202 downstream of the pump 206 relative to the flow of working fluid along the lubricant circuit 202. Thus, the accumulator 208 can receive a flow of pressurized working fluid (e.g., liquid working fluid, vapor working fluid, or both) from the pump 206 and the lubricant circuit 202. As will be appreciated, the accumulator 208 is configured to store the pressurized working fluid therein. For example, the accumulator 208 can include a container 210 and a separator 212 (e.g., a bladder, diaphragm, piston, etc.) disposed therein. In some embodiments, the separator 212 can divide the internal volume of the container 210 into a biasing chamber 214 (e.g., a gas chamber) on a first side of the separator 212 and a fluid chamber 216 (e.g., a liquid chamber, a working fluid chamber) on a second side of the separator 212. The fluid chamber 216 of the accumulator 208 is configured to receive pressurized working fluid from the lubricant circuit 202. The separator 212 may be a bladder or other flexible container pre-filled with a gas (e.g., nitrogen) to maintain the pressure of the working fluid within the fluid chamber 216. In other embodiments, the bias chamber 214 may be pre-filled with a gas. In still other embodiments, the bias chamber 214 may alternatively include a spring or other mechanical biasing component. In any case, the accumulator 208 may operate as a mechanical battery configured to supply (e.g., temporarily supply) pressurized working fluid from the fluid chamber 216 to the bearing assembly 150 via the lubricant circuit 202, for example, during periods of inactivity of the pump 206 (e.g., loss of power to the pump 206). For example, during periods of interruption in operation of the pump 206, the accumulator 208 may discharge the pressurized working fluid to the lubricant circuit 202 for supply to the bearing assembly 150. In this manner, the bearing assembly 150 can continue to operate to support the load on the shaft 104 (e.g., levitate the shaft 104) when operation of the pump 206 is resumed and / or when operation of the compressor 32 (e.g., the motor 50) is paused in a controlled manner. In some embodiments, the accumulator 208 can also operate to dampen oscillations in the flow of pressurized working fluid directed to the bearing assembly 150. Furthermore, the accumulator 208 can be configured to supply pressurized working fluid to the bearing assembly 150 when the vapor compression system 14 is started (e.g., prior to operation of the pump 206 and / or the compressor 32).

[0037] The fluid supply system 130 may also include other components disposed along the lubricant circuit 202, such as a check valve 218 (e.g., a ball check valve) disposed between the pump 206 and the accumulator 208. The check valve 218 may be configured to close and block the flow of the liquid working fluid from the pump 206 and along the lubricant circuit 202 toward the bearing assembly 150 based on the pressure of the liquid working fluid discharged by the pump 206. For example, the check valve 218 may close in response to the pressure of the liquid working fluid discharged by the pump 206 falling below a threshold value (e.g., a threshold value corresponding to a desired pressure of the liquid working fluid supplied to the bearing assembly 150). In such circumstances, pressurized liquid working fluid stored within the accumulator 208 may be supplied to the bearing assembly 150 (e.g., with the check valve 218 closed to block the flow of working fluid back to the pump 206) to enable the bearing assembly 150 to at least temporarily continue to operate to support the shaft 104 at the desired pressure along with the liquid working fluid supplied to the bearing assembly 150 via the accumulator 208.

[0038] In some embodiments, the fluid supply system 130 may include a filter 220 positioned along the lubricant circuit 202 (e.g., downstream of the accumulator 208 and upstream of the bearing assembly 150). The filter 220 may be configured to remove particles and / or moisture (e.g., water, water vapor) from the liquid working fluid before the liquid working fluid is directed to the bearing assembly 150.

[0039] The fluid supply system 130 may also include a heat exchanger 222 positioned along the lubricant circuit 202. The heat exchanger 222 is positioned upstream of the pump 206 relative to the flow direction of the working fluid through the lubricant circuit 202. In some embodiments, the heat exchanger 222 may be a brazed plate heat exchanger. In operation, the heat exchanger 222 may function as a subcooler configured to subcool the working fluid introduced into the lubricant circuit 202 from the liquid line portion 204. In this manner, the heat exchanger 222 may operate to ensure that the working fluid supplied to the pump 206 is in a liquid phase, which may reduce undesirable effects such as transient evaporation of the refrigerant at the pump 206, cavitation in the pump 206, and the like. The heat exchanger 222 is configured to establish a heat exchange relationship between the working fluid drawn from the liquid line portion 204 and a cooling fluid (e.g., an auxiliary cooling fluid) introduced into the heat exchanger 222 via the cooling fluid circuit 224. In some embodiments, the cooling fluid may be water. In such embodiments, the cooling fluid circuit 224 can be configured to supply cooling fluid from an external source. Additionally or alternatively, the cooling fluid circuit 224 can be configured to supply water or other cooling fluid (e.g., cooled via the evaporator 38) from a conditioning fluid conduit (e.g., the supply line 60S and / or the return line 60R described above). In some embodiments, the cooling fluid can be another portion of the working fluid from the working fluid circuit 200. In such embodiments, the cooling fluid circuit 224 can extend from the working fluid circuit 200 (e.g., the liquid line portion 204) to the heat exchanger 222. However, it should be understood that the cooling fluid circuit 224 can be configured to direct any suitable cooling fluid to the heat exchanger 222 to achieve cooling (e.g., subcooling) of a portion of the working fluid directed along the lubricant circuit 202 toward the bearing assembly 150 of the compressor 32.

[0040] As mentioned above, the bearing assemblies 150 are configured to receive a pressurized working fluid (e.g., a refrigerant) and discharge the working fluid toward the shaft 104 or the collar 128. Specifically, each of the bearing assemblies 150 includes one or more porous elements configured to direct the pressurized working fluid therethrough, instantaneously vaporize the pressurized working fluid, and discharge the pressurized vapor working fluid toward the shaft 104 or the collar 128. Thereafter, the working fluid may flow through the housing 102 of the compressor 32 (e.g., the motor 50) to one or more drain lines 226 of the bearing system 100. The drain lines 226 may be fluidically coupled to the interior of the housing 102. For example, the bearing system 100 may include a first drain line 228 extending from the housing 102 of the compressor 32 to the liquid line portion 204 of the working fluid circuit 200. The first drain line 228 may include a valve 230 (e.g., an electronic expansion valve) and / or may be configured to direct vapor working fluid from within the housing 102 to the liquid line portion 204 of the working fluid circuit 200. Additionally or alternatively, the bearing system 100 may include a second drain line 232 extending from the housing 102 to the evaporator 38 and / or a third drain line 234 extending from the housing 102 to the evaporator 38. In some embodiments, the second drain line 232 is configured to direct vapor working fluid from the housing 102 to the evaporator 38, and the third drain line 234 is configured to direct liquid working fluid from the housing 102 to the evaporator 38. In other words, the working fluid utilized by the bearing assembly 150 can be collected within the casing 102 of the compressor 32 in a vapor phase (e.g., a gas phase), a liquid phase, or both, and the bearing system 100 (e.g., the fluid supply system 130) can be configured to collect portions of the working fluid and return the portions in different phases (e.g., separately) to different portions of the working fluid circuit 200.

[0041] The vapor compression system 14 may also include a controller 250 (e.g., a control system, control panel, or control panel) communicatively coupled to one or more components of the vapor compression system 14 and / or the bearing system 100. The controller 250 is configured to monitor, adjust, and / or otherwise control the operation of the components of the vapor compression system 14, the bearing system 100, and / or the fluid supply system 130. For example, one or more control transmission devices, such as wires, cables, wireless communication devices, and the like, may communicatively couple the compressor 32, the motor 50, the pump 206, and / or any other components described herein. Such components may include a network interface that enables components of the vapor compression system 14 and / or the bearing system 100 to communicate via various protocols, such as Ethernet / IP, ControlNet, DeviceNet, or any other communication network protocol. Alternatively, the communication component may enable components of the vapor compression system 14 and / or the bearing system 100 to communicate via mobile telecommunications technology, Bluetooth®, near-field communication technology, and the like.

[0042] In some embodiments, the controller 250 may include part or all of the control panel 40, or may be another suitable controller included in the vapor compression system 14 and / or the bearing system 100. In any case, the controller 250 can be configured to control the components of the vapor compression system 14 and / or the bearing system 100 according to the techniques discussed herein. The controller 250 includes processing circuitry 252, such as one or more microprocessors, that can execute software for controlling the components of the vapor compression system 14 and / or the bearing system 100. The processing circuitry 252 may include multiple microprocessors, one or more "general-purpose" microprocessors, one or more special-purpose microprocessors, and / or one or more application-specific integrated circuits (ASICs), or some combination thereof. For example, the processing circuitry 252 may include one or more reduced instruction set computing (RISC) processors.

[0043] The controller 250 may also include a memory device 254 (e.g., memory) that can store information such as instructions, control software, lookup tables, configuration data, and the like. The memory device 254 may include volatile memory, such as random access memory (RAM), and / or non-volatile memory, such as read-only memory (ROM). The memory device 254 can store a variety of information and may be used for a variety of purposes. For example, the memory device 254 may store processor-executable instructions, including firmware or software, for execution by the processing circuitry 252, such as instructions for controlling components of the vapor compression system 14 and / or the bearing system 100. In some embodiments, the memory device 254 is a tangible, non-transitory, machine-readable medium that can store machine-readable instructions for execution by the processing circuitry 252. The memory device 254 may include ROM, flash memory, a hard disk, or any other suitable optical, magnetic, or solid-state storage medium, or a combination thereof. The memory device 254 can store data, instructions, and any other suitable information. It should be appreciated that the memory device 254 may store processor-executable instructions (eg, for execution via the processing circuitry 252 ) to implement the operation of any of the components described herein and to implement any of the functionality and / or operations described herein.

[0044] The controller 250 can be configured to control the operation of components of the vapor compression system 14, the bearing system 100, and / or the fluid supply system 130 based on detected operating parameters of the vapor compression system 14, the bearing system 100, and / or the fluid supply system 130. To this end, the vapor compression system 14 (e.g., the bearing system 100, the fluid supply system 130) includes one or more sensors 256 configured to detect operating parameters associated with or indicative of operating conditions of the vapor compression system 14, the bearing system 100, and / or the fluid supply system 130. For example, one or more of the sensors 256 can be positioned along the lubricant circuit 202 and can be configured to detect operating parameters of the working fluid directed through the lubricant circuit 202, such as temperature, pressure, flow rate, and the like. In some embodiments, the one or more sensors 256 can be configured to detect operating parameters associated with the motor 50, such as the rotational speed of the shaft 104, the torque on the shaft 104, the temperature of the motor 50, the temperature within the housing 102, and the like. The one or more sensors 256 may be configured to detect operating parameters of the bearing assembly 150 , such as detection of whether the one or more bearing assemblies 150 are in contact (eg, physical contact) with the shaft 104 , as further described below.

[0045] In some embodiments, one of the sensors 256 can be configured to detect an operating parameter associated with the accumulator 208, such as the pressure of the working fluid within the fluid chamber 216 and / or the pressure of the gas within the bias chamber 214. Additionally or alternatively, one or more of the sensors 256 can be configured to detect a level of the working fluid within the condenser 34, which can be referenced before and / or during startup of the bearing system 100, the fluid supply system 130, and / or the vapor compression system 14. As will be appreciated, each sensor 256 included in the vapor compression system 14 can be communicatively coupled to the controller 250. Thus, the controller 250 can receive data and / or feedback from the sensors 256 and can control the operation of the vapor compression system 14, the bearing system 100, and / or the fluid supply system 130 based on the feedback and / or data.

[0046] Figure 9 FIG. 1 is a schematic diagram of an embodiment of a vapor compression system 14 (eg, an HVAC&R system) including a bearing system 100 and a fluid supply system 130 for a compressor 32. The illustrated embodiment includes the same Figure 8 Similar elements and element numbers are used in the depicted embodiment, including lubricant circuit 202, heat exchanger 222 (e.g., a brazed plate heat exchanger), accumulator 208, pump 206 (e.g., a liquid pump), drain line 226, bearing assembly 150, and sensor 256. The illustrated embodiment also includes additional features that may be incorporated with bearing system 100 (e.g., fluid supply system 130).

[0047] As shown, the bearing system 100 (e.g., the fluid supply system 130) includes a differential pressure switch 270. The differential pressure switch 270 (e.g., a switch, a pressure switch) is fluidly coupled to the motor 50 (e.g., the housing 102, the interior volume of the housing 102) and the lubricant circuit 202 via a pressure circuit 272. The differential pressure switch 270 is configured to detect respective pressures associated with the working fluid within the motor 50 (e.g., within the housing 102) and the working fluid flowing within the lubricant circuit 202. For example, the differential pressure switch 270 may be fluidly coupled (e.g., via the pressure circuit 272) to the working fluid within the bearing assembly 150, the working fluid exhausted by the bearing assembly 150 within the housing 102, the first drain line 228, or other suitable pressures associated with the working fluid in the motor 50, the bearing assembly 150, and / or the compressor 32. The differential pressure switch 270 is also fluidly coupled to the lubricant circuit 202 at a location downstream of the pump 206, relative to the flow of the working fluid through the lubricant circuit 202. Thus, the differential pressure switch 270 may be configured to compare the working fluid within the electric motor 50 (eg, the housing 102 , the compressor 32 ) to the corresponding pressure of the working fluid being discharged by the pump 206 along the lubricant circuit 202 .

[0048] In some embodiments, differential pressure switch 270 may be actuated in response to a pressure differential between the working fluid discharged by pump 206 (e.g., lubricant circuit 202 downstream of pump 206) and the working fluid within or discharged by motor 50 (e.g., pressure within bearing assembly 150, housing 102) falling below a pressure differential threshold (e.g., 90 psi). That is, differential pressure switch 270 may be actuated in response to the pressure of the working fluid discharged by pump 206 not being greater than the pressure of the working fluid within or discharged by motor 50 (e.g., bearing assembly 150) by at least a threshold amount (e.g., the pressure differential threshold). Based on actuation of differential pressure switch 270, improper operation of pump 206 may be detected. To this end, differential pressure switch 270 may be communicatively coupled to controller 250, and controller 250 may be configured to adjust operation of one or more components of vapor compression system 14 (e.g., compressor 32, motor 50) based on a signal received from differential pressure switch 270 indicating actuation of differential pressure switch 270. For example, the controller 250 may be configured to shut down operation of the compressor 32 in a controlled manner in response to data or a signal received from the differential pressure switch 270 indicating that the pressure of the working fluid discharged by the pump 206 is not greater than the pressure of the working fluid within or discharged by the motor 50 (e.g., the bearing assembly 150), for example, by at least a threshold amount.

[0049] In the illustrated embodiment, the pump 206 is a pneumatic pump (e.g., a linear piston pump). Accordingly, the pump 206 is fluidly coupled to an air source 274 configured to supply air (e.g., pressurized air) to the pump 206 to enable operation of the pump 206. The pump 206 may also include a pressure relief valve configured to vent pressure generated by the pump 206 that exceeds a threshold. As will be appreciated, a linear piston pump may provide increased reliability and may be a cost-effective component for enabling the supply of pressurized fluid through the lubricant circuit 202.

[0050] The lubricant circuit 202 may further include one or more additional components, such as one or more sight glasses 276 and one or more check valves 278. The sight glasses 276 may enable an operator to visually verify the flow of working fluid through the lubricant circuit 202. In the illustrated embodiment, the check valves 278 may be configured to block the backflow of working fluid from the motor 50 (e.g., from the bearing assembly 150) into the lubricant circuit 202. The lubricant circuit 202 also includes a flow meter 280 (e.g., a liquid flow meter) configured to detect the flow (e.g., flow rate) of working fluid (e.g., liquid working fluid) to the bearing assembly 150 in the motor 50. The flow meter 280 is positioned downstream of the pump 206 and the accumulator 208. The flow meter 280 may be communicatively coupled to the controller 250 and may provide data indicating the amount (e.g., pressure, mass) of working fluid (e.g., liquid working fluid) provided to the bearing assembly 150. In some embodiments, the lubricant circuit 202 can include one or more heating elements 282 (e.g., heating tapes, resistive heaters) coupled thereto. The heating elements 282 can be configured to heat the liquid working fluid within the lubricant circuit 202 before supplying the working fluid to the bearing assembly 150. The heating elements 282 can also be communicatively coupled to the controller 250, and the controller 250 can control the heating elements 282 to heat the liquid working fluid within the lubricant circuit 202 by an amount that enables the liquid working fluid to evaporate (e.g., vaporize) instantaneously as the working fluid exits the bearing assembly 150 (e.g., from the porous element 126 of the bearing assembly 150) toward the shaft 104.

[0051] In the illustrated embodiment, the working fluid circuit 200 further includes a liquid recirculation conduit 284 extending from the base of the evaporator 38 to the liquid line portion 204 of the working fluid circuit 200. Thus, liquid working fluid within the evaporator 38 can flow (e.g., via gravity) to the liquid line portion 204. Specifically, during periods of inactivity of the vapor compression system 14, working fluid remaining within the evaporator 38 can condense into liquid, and the liquid working fluid can be directed from the evaporator 38 to the liquid line portion 204, which is fluidly coupled to the lubricant circuit 202, via the liquid recirculation conduit 284. In this manner, the liquid working fluid can be desirably redirected to the liquid line portion 204 to ensure that sufficient liquid working fluid is present in the liquid line portion 204 upon startup of the bearing system 100 and / or the fluid supply system 130. It should be appreciated that the operation of the bearing system 100 and / or the fluid supply system 130 may be initialized (e.g., via the controller 250) prior to startup of the compressor 32 of the vapor compression system 14 (e.g., prior to rotation of the shaft 104). As further described below, the bearing system 100 and / or the fluid supply system 130 may be operated prior to operation of the compressor 32 (e.g., rotation of the shaft 104), and the suspension of the shaft 104 within the compressor 32 (e.g., the housing 102) and from the bearing assembly 150 (e.g., the radial bearing 152) may be verified prior to initializing operation of the motor 50 (e.g., rotation of the shaft 104) to ensure proper operation of the compressor 32 and / or reduce undesirable contact, wear, and / or degradation of components of the compressor 32. In some embodiments, the liquid recirculation conduit 284 may include a valve 286. The valve 286 may be closed (e.g., via the controller 250) during steady-state operation of the vapor compression system 14 to block the flow of working fluid from the evaporator 38 to the liquid line portion 204.

[0052] Figure 10 and Figure 11 is a schematic diagram of a portion of an embodiment of a compressor 32 and a bearing system 100 illustrating a bearing assembly 150 having an embodiment of a radial bearing 152. In particular, Figure 10 The bearing assembly 150 is illustrated in a first configuration 300 (also referred to herein as a "contact configuration"), and Figure 11 The bearing assembly 150 is illustrated in a second configuration 302 (also referred to herein as a "non-contact configuration"). Figure 10 and Figure 11 The bearing assembly 150 includes similar elements and element numbers as described above, including the bearing housing 132 , the base portion 154 , and the liner portion 156 .

[0053] As similarly discussed above, the radial bearings 152 are configured to be disposed about the shaft 104 and to control and / or adjust the position of the shaft 104 in a radial direction relative to the axis 122. Specifically, the radial bearings 152 are configured to discharge pressurized fluid supplied via the lubricant circuit 202 toward the shaft 104 to achieve suspension of the shaft 104 extending within (e.g., radially within) the bearing assembly 150 having the radial bearings 152. In this manner, the radial bearings 152 enable efficient rotation of the shaft 104 within the housing 102 of the compressor 32. The bearing assembly 150 may include a plurality of radial bearings 152 arranged circumferentially around the shaft 104. One or more radial bearings 152 may be retained within a housing 304 of the motor 50 and / or the compressor 32. In some embodiments, the housing 304 may be a component of the housing 102. Alternatively, the housing 304 may be a separate component disposed within the housing 102, such as the bearing housing 132 described above.

[0054] In accordance with the present technology, the bearing system 100 is configured to detect contact between the shaft 104 and one or more of the radial bearings 152 (e.g., the pad portion 156). During operation of the vapor compression system 14 and / or the bearing system 100, the radial bearings 152 are configured to discharge working fluid toward the shaft 104 to achieve levitation and / or separation of the shaft 104 from the radial bearings 152, thereby achieving desired rotation of the shaft 104 within the housing 102 with reduced friction and improved efficiency. However, in some circumstances, one or more of the radial bearings 152 may contact the shaft 104. For example, during periods of non-operation of the vapor compression system 14, the bearing system 100, and / or the fluid supply system 130, the shaft 104 may rest (e.g., via gravity) on one or more of the radial bearings 152. Prior to operation of the compressor 32 (e.g., rotation of the shaft 104), operation of the bearing system 100 and / or the fluid supply system 130 may be initialized to supply working fluid to the bearing assembly 150, exhaust the working fluid from the radial bearings 152, and impinge the working fluid (e.g., vapor working fluid) on the shaft 104. In this manner, the fluid supply system 130 and the bearing assembly 150 may cause the shaft 104 to be lifted from the radial bearings 152 and suspended within the bearing assembly 150 prior to rotation of the shaft 104 (e.g., prior to operation of the compressor 32).

[0055] Thereafter, operation of the compressor 32 can be initiated. However, it is necessary to confirm that the shaft 104 does not contact any of the radial bearings 152 (e.g., the liner portion 156 ) after initializing operation of the bearing system 100 and / or the fluid supply system 130 and before initializing operation of the compressor 32. As another example, in some cases, the shaft 104 may contact one or more of the radial bearings 152 during operation of the compressor 32. For example, one or more components of the compressor 32 may not be operating as expected, and / or operating conditions of the compressor 32 may cause one or more of the radial bearings 152 to contact the shaft 104. In some cases, debris or other elements may be introduced or released within the compressor 32 and / or the motor 50, which may cause undesirable contact between the radial bearings 152 and the shaft 104. In any case, it is necessary to detect contact between the radial bearings 152 (e.g., the bearing assembly 150 , the liner portion 156 ) and the shaft 104 to evaluate the operation of the bearing system 100 and / or the compressor 32 and ensure proper operation of the bearing system 100 and the compressor 32.

[0056] Therefore, the bearing system 100 (e.g., the controller 250) is configured to detect contact between the radial bearing 152 and the shaft 104. As discussed above, components of the radial bearing 152 (e.g., the bearing assembly 150) may be formed from a metallic material, such as carbon, graphite, a metal composite, a composite matrix material, a sintered metal, or other suitable material (e.g., a conductive material). In particular, the base portion 154 and / or the pad portion 156 of the radial bearing 152 may be formed from a metallic material. The bearing housing 132 (e.g., the shell 304) may also be formed from a metallic material (e.g., steel). Therefore, one or more components of the bearing assembly 150 may be formed from a conductive material. The shaft 104 of the compressor 32 may also be formed from a metallic material (e.g., steel). To detect contact between the radial bearing 152 and the shaft 104, the bearing system 100 (e.g., the controller 250) is configured to detect and / or measure electrical continuity and discontinuity (e.g., electrical resistance) between the radial bearing 152 and the shaft 104. For example, the controller 250 of the bearing system 100 can be electrically coupled to the shaft 104 and can be electrically coupled to each radial bearing 152 (e.g., the bearing housing 132) of the bearing assembly 150. Thus, when one or more of the radial bearings 152 are in contact with the shaft 104, as in Figure 10 , the controller 250 can detect electrical continuity and / or reduced resistance between the radial bearing 152 and the shaft 104 (e.g., current supplied to the shaft 104 and / or the bearing assembly 150 via the controller 250). On the other hand, when the radial bearing 152 is not in contact with the shaft 104, as in Figure 11, the controller 250 can detect an electrical discontinuity and / or increased resistance between the radial bearing 152 and the shaft 104. In this manner, contact and non-contact between the radial bearing 152 and the shaft 104 can be detected by the bearing system 100.

[0057] In some embodiments, the bearing system 100 can be configured to establish and / or detect electrical continuity and discontinuity between the radial bearing 152 and the shaft 104 via an electrical current directed through materials (e.g., metallic materials, substrate materials) utilized to form the components of the radial bearing 152 (e.g., the bearing assembly 150). In other embodiments, the radial bearing 152 can include additional components, such as electrical contacts 306, coupled to the radial bearing 152 (e.g., the liner portion 156, the substrate portion 154, and / or the bearing housing 132) and / or the shaft 104, and / or embedded within the radial bearing and / or the shaft. Incorporating electrical contacts 306 with enhanced electrical conductivity can improve and / or enable more reliable detection of electrical continuity and discontinuity between the radial bearing 152 and the shaft 104 to determine whether the shaft 104 is in contact with the radial bearing 152.

[0058] The bearing system 100 and / or the compressor 32 (e.g., the motor 50) may include additional or alternative features to enable detection of contact between the shaft 104 and the radial bearing 152 via the electrical continuity and discontinuity techniques described herein. For example, in some embodiments, the shaft 104 may include conductive features, such as metal bristles 308 (e.g., brushes, carbon brushes) positioned on the outer diameter of the shaft 104. The metal bristles 308 of the shaft 104 may contact the radial bearing 152 to establish electrical continuity between the shaft 104 and the radial bearing 152, indicating contact therebetween. When the shaft 104 is appropriately lifted from the radial bearing 152 (e.g., via discharge of pressurized fluid from the bearing assembly 150 toward the shaft 104) and is not in contact with the radial bearing 152, the metal bristles 308 may not contact the radial bearing 152, which may reduce or eliminate electrical continuity therebetween (e.g., indicating an electrical discontinuity therebetween) to indicate separation of the radial bearing 152 from the shaft 104 and thereby indicate desired suspension of the shaft 104 from the radial bearing 152.

[0059] Based on the detection of electrical continuity, discontinuity, and / or resistance between the shaft 104 and the radial bearings 152, operation of the compressor 32 can be adjusted or controlled. For example, before startup of the compressor 32, the bearing system 100 and the fluid supply system 130 can be operated to direct working fluid through the fluid supply system 130 to the bearing assembly 150 and lift the shaft 104 from the bearing assembly 150 so that the shaft 104 floats within the bearing assembly 150 (e.g., without contact between the shaft 104 and the radial bearings 152). However, if the bearing system 100 (e.g., the controller 250) detects electrical continuity between the shaft 104 and one or more of the radial bearings 152, a fault can be triggered (e.g., by the controller 250) to indicate that operation of the compressor 32 should not be initiated. If, during operation of the compressor 32, the bearing system 100 detects electrical continuity between the shaft 104 and one or more of the radial bearings 152, another fault can be triggered (e.g., by the controller 250) indicating contact between the shaft 104 and the bearing assembly 150. In such cases, for example, the compressor 32 may be shut down to achieve rectification of the contact between the shaft 104 and the bearing assembly 150. Furthermore, each radial bearing 152 in the bearing assembly 150 may be individually monitored by the controller 250 to detect electrical continuity between the shaft 104 and the corresponding radial bearing 152. In some cases, sequential detection of contact between the shaft 104 and one or more of the radial bearings 152 of the bearing assembly 150 (e.g., sequentially around the circumference of the shaft 104) may indicate metallic debris orbiting around the shaft 104 between the bearing assembly 150 and the shaft 104, which may prompt a shutdown of the compressor 32 (e.g., via the controller 250).

[0060] In addition to directing a current or voltage through the radial bearings 152 and / or the shaft 104 to determine electrical continuity or discontinuity (e.g., contact) between the radial bearings 152 and the shaft 104, a current or voltage may also be directed through one or more of the radial bearings 152 (e.g., bearing assembly 150) to determine the amount of separation (e.g., fly height, lift height) between the radial bearings 152 and the shaft 104. Specifically, the conductivity or resistivity value of the working fluid exhausted from the radial bearings 152 toward the shaft 104 may be a known value (e.g., stored in the memory device 254). Based on the known conductivity or resistivity value of the working fluid, the magnitude of the distance from the shaft 104 to one or more of the radial bearings 152 may be calculated (e.g., by the controller 250). Based on the calculated distance between the shaft 104 and one or more of the radial bearings 152, the operation of the compressor 32 and / or the bearing system 100 (e.g., the fluid supply system 130, the pump 206) may be adjusted.

[0061] In some embodiments, the bearing assembly 150 and / or the shaft 104 may include additional or alternative components configured to enable detection of contact between the bearing assembly 150 and the shaft 104. For example, the bearing assembly 150 and / or the shaft 104 may include one or more of the sensors 256 configured to detect an operating parameter indicative of contact between the shaft 104 and one or more of the radial bearings 152. The one or more sensors 256 may include a proximity sensor, a temperature sensor, a voltage sensor, a current sensor, and / or other types of sensors. In embodiments of radial bearings 152 having temperature sensors, an increase in the detected temperature may indicate increased friction, and therefore increased contact, between the radial bearing 152 and the shaft 104.

[0062] Figure 10 and Figure 11 The radial bearing 152 illustrated in FIG. 1 also includes a damping element 320. One or more damping elements 320 may be positioned between the radial bearing 152 (e.g., the base portion 154) and the bearing housing 132 and / or between the bearing housing 132 and the housing 304. The damping elements 320 may be configured to reduce vibrations of the radial bearing 152 and / or the shaft 104. Additionally or alternatively, the damping elements 320 may be configured to adjust the frequency of vibrations induced in the radial bearing 152 and / or the shaft 104. The damping elements 320 may have any suitable shape, geometry, composition, size, stiffness, and / or other properties to enable desired tuning of the bearing assembly 150. In some embodiments, the damping elements 320 may be O-rings, elastomeric seals, polytetrafluoroethylene (PTFE) rings (e.g., C-rings, spring-energized C-rings), Teflon, coil springs, squeeze film dampers, or any combination thereof. In embodiments of the bearing assembly 150 having a squeeze film damper as one or more of the damping elements 320, the damping provided by the squeeze film damper can be adjusted (e.g., via an active fluid feedback damper). It should be understood that the features described above with reference to the radial bearing 152 can be similarly incorporated with the axial bearing.

[0063] As described in detail above, embodiments of the present invention are directed to a bearing system configured to enable and facilitate operation of a compressor in a vapor compression system with improved efficiency and reduced cost. Specifically, the bearing system described herein is configured to utilize a pressurized fluid, such as a working fluid (e.g., refrigerant) circulated through the vapor compression system, to support the load of a compressor shaft and enable rotation of the shaft within the compressor's housing. The pressurized fluid can also serve as a lubricant. To this end, the bearing system includes one or more bearings having porous bearing elements configured to receive the pressurized fluid. The pressurized fluid (e.g., liquid) can be directed through the porous bearing elements to contact the shaft within the compressor's housing. As the pressurized fluid is directed through the porous bearing elements and discharged from the porous bearing elements, it can vaporize or "flash-boil" to become a vapor or gas that contacts the shaft and forms a hydrostatic film around the shaft. In this way, the working fluid that circulates through the vapor compression system to exchange heat with other fluids (e.g., a conditioning fluid supplied to the load) can also serve as a lubricant to achieve the desired operation of the compressor. In fact, embodiments of the present invention enable the integration of bearings into compressors without utilizing a separate, dedicated lubricant (e.g., oil). The disclosed bearing systems can also be implemented at reduced costs (e.g., manufacturing, operating, and maintenance costs) compared to conventional bearings. Furthermore, the techniques discussed herein enable the integration and operation of bearing systems into compressors with simplified control schemes, improved reliability, and required monitoring.

[0064] While only certain features and embodiments have been illustrated and described, numerous modifications and variations may occur to those skilled in the art, such as variations in the size, dimensions, structure, shape, and proportions of various components, values ​​of parameters (e.g., temperature and pressure), mounting arrangements, material usage, color, orientation, and the like, without substantially departing from the novel teachings and advantages of the subject matter recited in the claims. The order or sequence of any process or method steps may be varied or resequenced according to alternative embodiments. It should be understood, therefore, that the appended claims are intended to cover all such modifications and variations that fall within the true spirit of the present disclosure.

[0065] Furthermore, in an effort to provide a concise description of exemplary embodiments, not all features of an actual implementation may be described, such as those not relevant to the best mode presently contemplated or those not relevant to implementation. It should be understood that in developing any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but would nevertheless be a routine task of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

[0066] The techniques presented and claimed herein are referenced and applied to physical objects and specific examples of a practical nature that clearly advance the technical field of the present invention and are therefore not abstract, intangible, or purely theoretical. In addition, if any claim appended to the end of this specification contains one or more elements designated as "means for [performing] [the function] ..." or "step for [performing] [the function] ...", then it is intended that such elements be interpreted in accordance with 35 USC 112(f). However, for any claim containing elements designated in any other manner, it is not intended that such elements be interpreted in accordance with 35 USC 112(f).

Claims

1. A heating, ventilation, air conditioning, and cooling (HVAC&R) system comprising: a compressor configured to circulate a working fluid along a working fluid circuit; a bearing disposed about a shaft of the compressor; and a fluid supply system configured to direct a portion of the working fluid from the working fluid circuit to the bearing, wherein the bearing is configured to discharge the portion of the working fluid toward the shaft.

2. The HVAC&R system of claim 1 , wherein the fluid supply system is configured to supply the portion of the working fluid to the bearing in a liquid phase, and the bearing is configured to exhaust the portion of the working fluid toward the shaft in a vapor phase.

3. The HVAC&R system of claim 2, wherein the bearing comprises a porous material, and the bearing is configured to direct the portion of the working fluid through the porous material to vaporize the portion of the working fluid exhausted toward the shaft.

4. The HVAC&R system of claim 1 , wherein the fluid supply system includes a lubricant circuit extending from the working fluid circuit to the compressor, the lubricant circuit being configured to receive the portion of the working fluid from a liquid line portion of the working fluid circuit extending from a condenser of the working fluid circuit.

5. The HVAC&R system of claim 4, wherein the fluid supply system comprises a linear piston pump disposed along the lubricant circuit.

6. The HVAC&R system of claim 5 , wherein the fluid supply system includes a heat exchanger positioned upstream of the linear piston pump along the lubricant circuit relative to a flow direction of the portion of the working fluid along the lubricant circuit, wherein the heat exchanger is configured to bring the portion of the working fluid into heat exchange relationship with a cooling fluid to transfer heat from the portion of the working fluid to the cooling fluid.

7. The HVAC&R system of claim 5 , wherein the fluid supply system includes an accumulator fluidly coupled to the lubricant circuit downstream of the linear piston pump along a flow direction of the lubricant circuit relative to the portion of the working fluid, wherein the accumulator is configured to receive and hold a quantity of the portion of the working fluid from the lubricant circuit.

8. The HVAC&R system of claim 5 , wherein the fluid supply system includes a differential pressure switch fluidly coupled to the lubricant circuit downstream of the linear piston pump and to an interior of a housing of the compressor relative to a flow direction of the portion of the working fluid along the lubricant circuit, wherein the differential pressure switch is configured to actuate in response to a pressure differential between the lubricant circuit downstream of the linear piston pump and the interior of the housing being below a pressure differential threshold.

9. The HVAC&R system of claim 8, comprising a controller communicatively coupled to the differential pressure switch, wherein the controller is configured to pause operation of the compressor in response to actuation of the differential pressure switch.

10. The HVAC&R system of claim 1 , comprising the shaft and a controller electrically coupled to the shaft and the bearing, wherein the shaft comprises a first conductive material, the bearing comprises a second conductive material, and the controller is configured to detect contact between the shaft and the bearing based on detected electrical continuity between the shaft and the bearing.

11. The HVAC&R system of claim 10, wherein the controller is configured to: operating the fluid supply system to direct the portion of the working fluid from the working fluid circuit to the bearing; detecting separation of the shaft from the bearing based on a detected electrical discontinuity between the shafts; and Operation of the compressor is initialized to rotate the shaft in response to the detected separation of the shaft from the bearing.

12. A heating, ventilation, air conditioning, and refrigeration (HVAC&R) system comprising: a working fluid circuit comprising a compressor, an evaporator, and a condenser, wherein the compressor is configured to circulate a working fluid along the working fluid circuit; a bearing assembly for the compressor, wherein the bearing assembly is disposed about a shaft of the compressor, the bearing assembly comprising a plurality of radial bearing segments arranged around a circumference of the shaft, and each radial bearing segment of the plurality of radial bearing segments comprising a porous material; and A fluid supply circuit extends from the working fluid circuit to the bearing assembly, wherein the fluid supply circuit is configured to direct a flow of working fluid from the working fluid circuit to the bearing assembly.

13. The HVAC&R system of claim 12 , wherein a radial bearing segment of the plurality of radial bearing segments is configured to receive a portion of the working fluid flow via the fluid supply circuit, direct the portion of the working fluid flow through the porous material of the radial bearing segment, and discharge the portion of the working fluid flow toward the shaft.

14. The HVAC&R system of claim 13 , wherein the fluid supply circuit is configured to direct the working fluid flow from the working fluid circuit to the bearing assembly in a liquid phase, and the porous material of the radial bearing segment is configured to vaporize the portion of the working fluid flow, thereby discharging the portion of the working fluid flow toward the shaft in a vapor phase.

15. The HVAC&R system of claim 13, wherein the radial bearing segment of the plurality of radial bearing segments comprises: a base portion defining a cavity configured to receive the portion of the flow of working fluid via the fluid supply circuit; and A gasket portion is coupled to the base portion, wherein the gasket portion comprises the porous material and is configured to direct the portion of the working fluid flow from the cavity to the shaft.

16. The HVAC&R system of claim 12, wherein the porous material is a conductive material comprising carbon, graphite, a composite matrix material, a sintered metal, or a combination thereof.

17. The HVAC&R system of claim 12, wherein the working fluid circuit includes a liquid line portion extending from the condenser and configured to receive liquid working fluid from the condenser, and the fluid supply circuit extends from the liquid line portion to the bearing assembly.

18. A heating, ventilation, air conditioning, and refrigeration (HVAC&R) system comprising: a bearing configured to be positioned about a shaft of a compressor, wherein the bearing comprises a porous material and the bearing is configured to discharge a fluid flow through the porous material and toward the shaft of the compressor; and a fluid supply system configured to direct the fluid flow from a working fluid circuit of the HVAC&R system to the bearing, The fluid supply system is configured to supply the fluid flow to the bearing in a liquid phase, and the bearing is configured to discharge the fluid flow toward the shaft in a vapor phase.

19. The HVAC&R system of claim 18 , comprising the working fluid circuit, wherein the compressor is positioned along the working fluid circuit and is configured to direct the working fluid along the working fluid circuit, the fluid supply system comprising a fluid supply circuit extending from the working fluid circuit to the bearing, and the fluid supply circuit is configured to direct a portion of the working fluid from the working fluid circuit to the bearing as the fluid flow.

20. The HVAC&R system of claim 19, comprising: a heat exchanger positioned along the fluid supply loop, wherein the heat exchanger is configured to transfer heat from the portion of the working fluid to a cooling fluid; and A pump is positioned downstream of the heat exchanger along the fluid supply circuit relative to a flow direction of the portion of the working fluid along the fluid supply circuit, wherein the pump is configured to direct the portion of the working fluid to the bearing.

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