Fluid supply system for bearings of HVAC&r system

Abstract

A heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system includes a working fluid circuit including an evaporator, a condenser, and a compressor. The HVAC&R system also includes a fluid supply system including a lubricant circuit configured to direct a flow of working fluid from the working fluid circuit to a bearing of the compressor. The lubricant circuit includes a heat exchanger configured to place the flow of working fluid in a heat exchange relationship with a cooling fluid.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from and the benefit of U.S. Provisional Application No. 63 / 538,463, entitled “FLUID SUPPLY SYSTEM FOR BEARINGS OF HVAC&R SYSTEM,” filed Sep. 14, 2023, and U.S. Provisional Application No. 63 / 443,921, entitled “BEARING SYSTEM FOR HVAC&R SYSTEM,” filed Feb. 7, 2023, each of which is hereby incorporated by reference in its entirety for all purposes.BACKGROUND

[0002] This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are 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. Accordingly, it should be understood that these statements are to 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 phases between vapor, liquid, and combinations thereof in response to exposure to different temperatures and pressures within components of the chiller system. The chiller system may place the working fluid in a heat exchange relationship with a conditioning fluid (e.g., water) and may deliver the conditioning fluid to conditioning equipment and / or a conditioned environment serviced by the chiller system. In such applications, the conditioning fluid may be directed through downstream equipment, such as air handlers, to condition other fluids, such as air in a building. The chiller system may include a compressor configured to pressurize the working fluid and circulate the working fluid through a working fluid circuit of the chiller system. In some applications, a shaft of the compressor may be driven in rotation by a motor in order to drive rotation of an impeller of the compressor that pressurizes the working fluid. Traditionally, the compressor includes bearings configured to facilitate rotation of the shaft. Unfortunately, existing bearings utilized with compressors may be complex, expensive, and / or may contribute to inefficiencies in operation of the chiller system.SUMMARY

[0004] A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below.

[0005] In one embodiment, a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system includes a working fluid circuit including an evaporator, a condenser, and a compressor. The HVAC&R system also includes a fluid supply system including a lubricant circuit configured to direct a flow of working fluid from the working fluid circuit to a bearing of the compressor. The lubricant circuit includes a heat exchanger configured to place the flow of working fluid in a heat exchange relationship with a cooling fluid.

[0006] In another embodiment, a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system, includes a working fluid circuit including a condenser, an evaporator, and a compressor. The working fluid circuit is configured to circulate a working fluid therethrough. The HVAC&R system also includes a lubricant circuit configured to direct a portion of the working fluid from the working fluid circuit to a bearing of the compressor. Additionally, the HVAC&R system includes a heat exchanger disposed along the lubricant circuit between the working fluid circuit and the bearing, relative to a flow direction of the portion of the working fluid along the lubricant circuit. Furthermore, the HVAC&R system includes a cooling fluid circuit configured to circulate a cooling fluid through the heat exchanger. The heat exchanger is configured to facilitate heat transfer from the portion of the working fluid to the cooling fluid. Additionally, the HVAC&R system includes a pump disposed along the lubricant circuit and configured to direct the flow of working fluid from the heat exchanger to the bearing.

[0007] In another embodiment, a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system includes a condenser disposed along a working fluid circuit. The HVAC&R system also includes a compressor disposed along the working fluid circuit, wherein the compressor comprises a bearing. Furthermore, the HVAC&R system includes a heat exchanger of a lubricant circuit. The heat exchanger is configured to receive a flow of working fluid from the condenser and to place the flow of working fluid in a heat exchanger relationship with a cooling fluid. The lubricant circuit is configured to direct the flow of working fluid from the heat exchanger to the bearing.DRAWINGS

[0008] Various aspects of this disclosure may be better understood upon reading the following detailed description and upon reference to the drawings in which:

[0009] FIG. 1 is a perspective view of an embodiment of a building that may utilize a heating, ventilating, air conditioning, and / or refrigeration (HVAC&R) system in a commercial setting, in accordance with an aspect of the present disclosure;

[0010] FIG. 2 is a perspective view of an embodiment of a vapor compression system, in accordance with an aspect of the present disclosure;

[0011] FIG. 3 is a schematic of an embodiment of a vapor compression system, in accordance with an aspect of the present disclosure;

[0012] FIG. 4 is a schematic of an embodiment of a vapor compression system, in accordance with an aspect of the present disclosure;

[0013] FIG. 5 is a cross-sectional side view of an embodiment of a compressor of a vapor compression system, illustrating a bearing system of the compressor, in accordance with an aspect of the present disclosure;

[0014] FIG. 6 is a schematic of an embodiment of a vapor compression system including a fluid supply system of a bearing system for a compressor, in accordance with an aspect of the present disclosure;

[0015] FIG. 7 is a schematic of an embodiment of a vapor compression system including a fluid supply system of a bearing system for a compressor, in accordance with an aspect of the present disclosure;

[0016] FIG. 8 is a schematic of an embodiment of a vapor compression system including a fluid supply system of a bearing system for a compressor, in accordance with an aspect of the present disclosure; and

[0017] FIG. 9 is a schematic of an embodiment of a vapor compression system including a fluid supply system of a bearing system for a compressor, in accordance with an aspect of the present disclosure.DETAILED DESCRIPTION

[0018] One or more specific embodiments will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated 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 developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

[0019] When introducing elements of various embodiments of the present disclosure, the articles “a,”“an,” and “the” are intended to mean that there are one or more of the 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. Additionally, 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.

[0020] As used herein, the terms “approximately,”“generally,” and “substantially,” and so forth, are intended to convey that the property value being described may be within a relatively small range of the property value, as those of ordinary skill would understand. For example, when a property value is described as being “approximately” equal to (or, for example, “substantially similar” to) a given value, this is intended to mean that the property value may be within + / −5%, within + / −4%, within + / −3%, within + / −2%, within + / −1%, or even closer, of the given value. Similarly, when a given feature is described as being “substantially parallel” to another feature, “generally perpendicular” to another feature, and so forth, this is intended to mean that the given feature is within + / −5%, within + / −4%, within + / −3%, within + / −2%, within + / −1%, or even closer, to having the described nature, such as being parallel to another feature, being perpendicular to another feature, and so forth. Further, it should be understood that mathematical terms, such as “planar,”“slope,”“perpendicular,”“parallel,” and so forth are intended to encompass features of surfaces or elements as understood to one of ordinary skill in the relevant art, and should not be rigidly interpreted as might be understood in the mathematical arts. For example, a “planar” surface is intended to encompass a surface that is machined, molded, or otherwise formed to be substantially flat or smooth (within related 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., incline) with respect to a point of reference using techniques and tools available to one of ordinary skill in the art.

[0021] Embodiments of the present disclosure relate to a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system (e.g., a chiller) including a vapor compression system (e.g., vapor compression circuit) having a compressor. In operation, the compressor may pressurize a working fluid within the vapor compression system and direct the working fluid to a condenser (e.g., a first heat exchanger), which may cool and condense the working fluid. The condensed working fluid may be directed to an expansion device, which may reduce a pressure of the working fluid, further cooling the working fluid. From the expansion device, the cooled working fluid may be directed to an evaporator (e.g., a second heat exchanger), where the working fluid may be placed in a heat exchange relationship with a conditioning fluid to cool the conditioning fluid. The conditioning fluid may be circulated between the evaporator and a structure, such as a building, where the conditioning fluid is used to cool an air flow delivered to a conditioned space of the structure. In some embodiments, an air handling unit (AHU) of the HVAC&R system may receive the conditioning fluid from the chiller and utilize the conditioning fluid to cool the air flow delivered to the conditioned space. The conditioning fluid may then be returned to the evaporator to be cooled again.

[0022] In some embodiments, the compressor may include a bearing system including bearings (e.g., hydrostatic bearings) that utilize a pressurized fluid to support and lubricate a rotating shaft of the compressor. For example, the working fluid may be a refrigerant, and the bearing system may include a lubricant circuit extending from the working fluid circuit and direct a portion of the working fluid from the working fluid circuit into the bearings of the compressor. That is, the portion of the working fluid in the lubricant circuit may be utilized as a lubricating fluid. The lubricant circuit may include a pump configured to pump the working fluid toward the bearings of the compressor. In accordance with present techniques, the bearings may receive the working fluid in a liquid phase and may discharge the working fluid toward the rotating shaft in a gaseous phase. In this way, the working fluid, which is configured to exchange heat with the conditioning fluid as part of the working fluid circuit, may also be utilized to enable the bearings to support (e.g., levitate) the shaft of the compressor and enable rotation of the shaft.

[0023] It may be desirable to maintain the supply of the working fluid to the bearings at a suitable pressure level. For example, a threshold pressure of the working fluid may be demanded for the bearings to effectively lubricate and / or support the shaft of the compressor. To pressurize the working fluid, the pump may be configured to operate at a desired speed. However, in addition to the pump speed, the pressure of pumped working fluid may depend on a temperature and phase of the working fluid. For example, the pump may receive the working fluid in a liquid phase, such as from the condenser of the working fluid circuit. Then, changes in pressure may cause the working fluid to cavitate or vaporize (e.g., flash) within the pump and / or the lubricant circuit. As a result, the pressure of the pumped working fluid may be reduced, which may impede bearing performance in some instances. Additionally, cavitation of the working fluid may cause undesirable wear to the pump and other components of the lubricant circuit. Therefore, improved fluid supply systems for compressor bearings are desired.

[0024] Accordingly, present embodiments are directed to a fluid supply system configured to direct subcooled working fluid, such as from a condenser of a working fluid circuit, to a bearing system of a compressor disposed along the working fluid circuit. In particular, fluid supply systems described herein include a heat exchanger configured to cool working fluid directed from the condenser to a pump. For example, the heat exchanger may enable transfer of heat from the working fluid to a cooling fluid, such that the working fluid becomes subcooled to a desired temperature (e.g., a temperature corresponding to the pump speed). In this way, the working fluid may remain in a liquid phase as the pump drives flow of the working fluid toward the bearings of the compressor. As the pump speed varies, the rate of heat transfer between the working fluid and the cooling fluid may be varied to provide a corresponding degree of subcooling. For example, a valve may modulate the flow rate of the cooling fluid through the heat exchanger. Moreover, the flow rate of the cooling fluid may be controlled based on a temperature, pressure, and / or flow rate of the working fluid (e.g., within the lubricant circuit). Additionally, a controller may control the flow of cooling fluid through the heat exchanger, and thereby control an amount of heat transfer between the working fluid and the cooling fluid, such as based on vibrations or sounds caused by cavitation within the pump. As a result, the working fluid may be pumped toward the bearings of the compressor at a desired pressure, temperature, and / or phase suitable for operation of the bearings. Moreover, the subcooling of the working fluid may ensure that the working fluid reaches the bearings in a liquid state, even if the working fluid flow experiences a pressure drop (e.g., during a coast-down operation or an interruption of the pump) during flow to the bearings. In this way, present embodiments provide a fluid supply system configured to maintain a desired, pressurized flow of working fluid to a bearing system, thereby mitigating wear and degradation to components of the bearing system and the compressor.

[0025] Turning now to the drawings, FIG. 1 is a perspective view of an embodiment of a heating, ventilating, air conditioning, and / or refrigeration (HVAC&R) system 10 in a building 12 for a typical commercial setting. The HVAC&R system may include a vapor compression system 14 to supply chilled liquid to cool the building 12 and a boiler 16 to supply warm liquid to heat the building 12. The vapor compression system 14, also referred to herein as a chiller, may circulate a working fluid (e.g., refrigerant) that is cooled by a cooling fluid (e.g., liquid such as water) in a condenser of the vapor compression system 14, and that is heated by a conditioning fluid (e.g., liquid, such as water) in an evaporator of the vapor compression system 14. The cooling fluid may be provided by a cooling tower which cools the cooling fluid via, for example, ambient air. The conditioning fluid, cooled by the working fluid as noted above, may be utilized to cool an air flow provided to conditioned spaces of the building 12.

[0026] The HVAC&R system 10 may also include an air distribution system which circulates air through the building 12. The air distribution system can also include an air return duct 18, an air supply duct 20, and / or an air handler 22. In some embodiments, the air handler 22 may include a heat exchanger that is connected to the boiler 16 and the vapor compression system 14 by conduits 24. The heat exchanger in the air handler 22 may receive either heated liquid from the boiler 16 or the conditioning fluid (e.g., chilled liquid such as water) from the vapor compression system 14, depending on the mode of operation of the HVAC&R system 10. The HVAC&R system 10 is shown with a separate air handler on each floor of 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

[0027] FIGS. 2 and 3 illustrate embodiments of the vapor compression system 14, or chiller, which can be used in the HVAC&R system 10. The vapor compression system 14 may circulate a working fluid through a circuit (e.g., working fluid circuit) starting with a compressor 32, such as a centrifugal compressor. The circuit may also include a condenser 34, an expansion valve(s) or device(s) 36, and an evaporator 38. The vapor compression system 14 may further include a control panel 40 that has an analog to digital (A / D) converter 42, a microprocessor 44, a non-volatile memory 46, and / or an interface board 48.

[0028] Some examples of fluids that may be used as working fluids in the vapor compression system 14 are hydrofluorocarbon (HFC) based refrigerants, for example, R-410A, R-407, R-134a, hydrofluoro olefin (HFO), “natural” refrigerants like ammonia (NH3), R-717, carbon dioxide (CO2), R-744, or hydrocarbon-based refrigerants, water vapor, or any other suitable working fluid. Other possible working fluids include R-123, R-514A, R-1130yd, R-1233zd, R-134a, R-1142ze, R-1142yf, R-1311, R-32, and R-410A. In some embodiments, the vapor compression system 14 may be configured to efficiently utilize working fluids having a normal boiling point of about 19 degrees Celsius (66 degrees Fahrenheit) at one atmosphere of pressure, also referred to as low pressure refrigerants, versus a medium pressure working fluid, such as R-134a. As used herein, “normal boiling point” may refer to a boiling point temperature measured at one atmosphere of pressure.

[0029] In some embodiments, the vapor compression system 14 may use one or more of a variable speed drive (VSDs) 52, a motor 50, the compressor 32, the condenser 34, the expansion valve or device 36, and / or the evaporator 38. The motor 50 may drive the compressor 32 during a normal operating mode and may be powered by a variable speed drive (VSD) 52. The VSD 52 receives alternating current (AC) power during the normal operating mode, where the AC power includes a particular fixed line voltage and fixed line frequency from an AC power source, and provides power having a variable voltage and frequency to the motor 50. In other embodiments, the motor 50 may be powered directly from an AC or direct current (DC) power source. The 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 motor.

[0030] The compressor 32 compresses a working fluid vapor and delivers the vapor to the condenser 34 through a discharge passage. In some embodiments, the compressor 32 may be a centrifugal compressor. The working fluid vapor delivered by the compressor 32 to the condenser 34 may transfer heat to a cooling fluid (e.g., water or air) in the condenser 34. The working fluid vapor may condense to a working fluid liquid in the condenser 34 as a result of thermal heat transfer with the cooling fluid. The liquid working fluid from the condenser 34 may flow through the expansion device 36 to the evaporator 38. In the illustrated embodiment of FIG. 3, the condenser 34 is water cooled and includes a tube bundle 54 connected to a cooling tower 56, which supplies the cooling fluid to the condenser 34.

[0031] The liquid working fluid delivered to the evaporator 38 may absorb heat from a conditioning fluid that is subsequently routed to a load 62 (e.g., the building 12 of FIG. 1). For example, the conditioning fluid may be cooled by the working fluid in the evaporator 38, and then may be utilized in the building 12 of FIG. 1 to condition an air flow provided to condition a space in the building 12. The liquid working fluid in the evaporator 38 may undergo a phase change from the liquid working fluid to a working fluid vapor. As shown in the illustrated embodiment of FIG. 3, 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. 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 return line 60R and exits the evaporator 38 via supply line 60S. The evaporator 38 may reduce the temperature of the conditioning fluid in the tube bundle 58 via thermal heat transfer with the working fluid. The tube bundle 58 in the evaporator 38 can include a plurality of tubes and / or a plurality of tube bundles. In any case, the vapor working fluid exits the evaporator 38 and returns to the compressor 32 by a suction line to complete the cycle.

[0032] FIG. 4 is a schematic of an embodiment of the vapor compression system 14 with an intermediate circuit 64 incorporated between the condenser 34 and the expansion device 36. The intermediate circuit 64 may have an inlet line 68 that is directly fluidly connected to the condenser 34. In other embodiments, the inlet line 68 may be indirectly fluidly coupled to the condenser 34. As shown in the illustrated embodiment of FIG. 4, 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 tank (e.g., a flash intercooler). In other embodiments, the intermediate vessel 70 may be configured as a heat exchanger or a “surface economizer.” In the illustrated embodiment of FIG. 4, the intermediate vessel 70 is used as a flash tank, and the first expansion device 66 is configured to lower 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 for further expansion of the liquid working fluid due to a pressure drop experienced by the liquid working fluid when entering the intermediate vessel 70 (e.g., due to a rapid increase in volume experienced when entering the intermediate vessel 70). The vapor working fluid in the intermediate vessel 70 may be drawn by the compressor 32 through a suction line 74 of the compressor 32. In other embodiments, the vapor working fluid in the intermediate vessel 70 may be drawn to an intermediate stage of the compressor 32 (e.g., not the suction stage). The liquid working fluid that collects in the intermediate vessel 70 may be at a lower enthalpy than the liquid working fluid exiting the condenser 34 due to expansion of the working fluid at the expansion device 66 and / or in the intermediate vessel 70. The liquid working fluid from intermediate vessel 70 may then flow through line 72 and through a second expansion device 36 to the evaporator 38.

[0033] In accordance with present embodiments, the compressor 32 may be a centrifugal compressor (e.g., a hermetic compressor) having a levitated rotor or shaft. To this end, the vapor compression system 14 includes a bearing system with one or more bearings configured to support a load of the shaft of the compressor 32. The bearing system is configured to direct a pressurized fluid (e.g., liquid, working fluid, refrigerant) through the bearings, and the bearings are configured to discharge the fluid toward and against the shaft in order to enable levitation 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 the pressurized fluid toward the shaft within a housing of the compressor 32. In this way, the bearing system may support a 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 may be a working fluid (e.g., refrigerant) circulated through the vapor compression system 14. Thus, the vapor compression system 14 may not utilize a dedicated lubricant, such as oil, to support and enable rotation of the shaft of the compressor 32. Further, the bearing system may be incorporated with the vapor compression system 14 at reduced costs, as compared to other existing bearing system designs. The disclosed embodiments also enable improved (e.g., simplified) control of the bearing system, as well as more efficient operation of the vapor compression system 14.

[0034] With the foregoing in mind, FIG. 5 is a cross-sectional side view of an embodiment of the compressor 32 including a bearing system 100, in accordance with 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, such as 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 rotation of the impeller 106. Rotation of the impeller 106 may drive a working fluid (e.g., refrigerant) to flow through a working fluid flow path 110 (e.g., from the evaporator 38, from the intermediate vessel 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 onto the working fluid and discharge the working fluid to a diffuser passage 114 of the compressor 32. The working fluid may be directed from the diffuser passage 114 to a volute 116 of the compressor 32 and from the volute 116 to a condenser (e.g., the condenser 34) for heat exchange with a fluid, such as a cooling fluid.

[0035] In the illustrated embodiment, the compressor 32 (e.g., bearing system 100) includes a first bearing 118 (e.g., a radial bearing, bearing assembly, porous bearing) and a second bearing 120 (e.g., a radial bearing, bearing assembly, porous bearing) configured to control and / or adjust a position (e.g., radial position) of the shaft 104 relative to an axis 122 (e.g., rotational axis, central axis) of the shaft 104. For example, the first bearing 118 and the second bearing 120 may be configured to support a load of the shaft 104, such that the shaft 104 levitates within the first bearing 118 and the second bearing 120. The first bearing 118 and the second bearing 120 may also be configured to block movement (e.g., bending, radial movement, eccentric rotation) of the shaft 104 crosswise to the axis 122. The compressor 32 (e.g., bearing system 100) further includes a third bearing 124 (e.g., thrust bearing, axial bearing, bearing assembly, porous bearing) configured to control and / or adjust a position (e.g., axial position) of the shaft 104 along the axis 122. For example, the third bearing 124 may be configured to block or limit movement (e.g., translation) of the shaft 104 along the axis 122.

[0036] As mentioned above, the bearing system 100 is configured to direct a pressurized fluid to 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) circulated through the vapor compression system 14 having the compressor 32. However, it should be appreciated 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 received pressurized fluid and direct the pressurized fluid towards the shaft 104 to establish a high-pressure fluid film (e.g., vapor film) about the shaft 104 between the first bearing 118 and the second bearing 120 and the shaft 104. In this way, the pressurized fluid may cause the shaft 104 to levitate from the first bearing 118 and the second bearing 120, thereby enabling desired rotation of the shaft 104 about the axis 122. The one or more porous elements 126 of the third bearing 124 may receive pressurized fluid and direct the pressurized fluid towards a collar 128 (e.g., thrust collar) of the third bearing 124. In this way, the pressurized fluid may apply a force to the collar 128 and enable adjustable positioning of the shaft 104 along the axis 122.

[0037] The bearing system 100 includes a fluid supply system 130 configured to supply pressurized fluid to the bearings (first bearing 118, second bearing 120, and / or third bearing 124) of the bearing system 100. 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. An additional bearing housing 132 may be utilized with the third bearing 124. In other embodiments, the second bearing 120 and the third bearing 124 may be packaged together in a common bearing housing 132. The pressurized fluid may be directed through the bearing housings 132 to the corresponding porous elements 126 retained within each bearing housing 132. The fluid supply system 130 is described in further detail below. It should be appreciated that the compressor 32 may include any suitable number or type (e.g., radial, axial) of bearings incorporating the present techniques, and the bearings may be positioned at any suitable location within the housing 102 of the compressor 32.

[0038] FIG. 6 is a schematic of an embodiment of the vapor compression system 14 (e.g., HVAC&R system) including the bearing system 100 for the compressor 32. The vapor compression system 14 includes elements similar to those discussed above, including the compressor 32, the motor 50, the condenser 34, and the evaporator 38 (e.g., falling film evaporator) arranged along a working fluid circuit 200 (e.g., refrigerant circuit). Working fluid (e.g., refrigerant) may flow from an outlet of the condenser 34 toward the evaporator 38 via a liquid line portion 202 of the vapor compression system 14. Although the liquid line portion 202 is nominally configured to direct liquid working fluid (e.g., liquid refrigerant) from the condenser 34 to the evaporator 38, the working fluid in the liquid line portion 202 may include working fluid in other states, such as vapor or mixed vapor. For example, the liquid line portion 202 may include gaseous working fluid during certain operating conditions of the vapor compression system 14, such as a startup state or a coast-down state. Additionally, the pressure of the working fluid in the liquid line portion 202 may vary, based on an operating condition or parameter of the vapor compression system 14, or based on the state (e.g., phase, temperature) of the working fluid. For example, the pressure in the liquid line portion 202 may be less than a pressure of fluid delivered to the bearings.

[0039] In accordance with present techniques, the bearing system 100 also includes the fluid supply system 130 configured to direct pressurized fluid to the bearings (e.g., first bearing 118) of the bearing system 100. In particular, the fluid supply system 130 is configured to direct a portion of the working fluid (e.g., refrigerant) circulated through the working fluid circuit 200 to the bearing assemblies 150. To this end, the fluid supply system 130 includes a lubricant circuit 204 (e.g., fluid supply circuit) extending from the working fluid circuit 200 to the bearing assemblies 150 via a fluid conduit 205.

[0040] In the illustrated embodiment, the lubricant circuit 204 extends from the liquid line portion 202 of the working fluid circuit 200 to the bearing assemblies 150. Various components are disposed along the lubricant circuit 204 and are configured to enable desirable supply of the working fluid to the bearing assemblies 150 to enable the bearing assemblies 150 to support a load of the shaft 104 of the compressor 32. For example, the fluid supply system 130 includes a pump 206 (e.g., liquid pump) disposed along the lubricant circuit 204 and configured to direct flow of the working fluid (e.g. liquid working fluid) along the lubricant circuit 204 from the liquid line portion 202 of the working fluid circuit 200 to the bearing assemblies 150 of the motor 50 (e.g., compressor 32). The pump 206 may be a linear piston pump, in some embodiments, and the pump 206 may be driven electrically, pneumatically, mechanically, electromechanically, and / or via another suitable technique. In some embodiments, the pump 206 may operate without utilizing oil or other dedicated lubricant.

[0041] The fluid supply system 130 also includes a pressure accumulator 208 fluidly coupled to the lubricant circuit 204. The pressure accumulator 208 is fluidly coupled to the lubricant circuit 204 downstream of the pump 206 relative to a flow of working fluid along the lubricant circuit 204. Thus, the pressure accumulator 208 may receive a pressurized flow of working fluid (e.g., liquid working fluid, vapor working fluid, or both) from the pump 206 and the lubricant circuit 204. As will be appreciated, the pressure accumulator 208 is configured to store pressurized working fluid therein. For example, the pressure accumulator 208 may include a vessel 210 and a separator 212 (e.g., bladder, diaphragm, piston, etc.) disposed therein. In some embodiments, the separator 212 may divide an internal volume of the vessel 210 into a biasing chamber 214 (e.g., gas chamber) on a first side of the separator 212 and a fluid chamber 216 (e.g., liquid chamber, working fluid chamber) on a second side the separator 212. The fluid chamber 216 of the pressure accumulator 208 is configured to receive pressurized working fluid from the lubricant circuit 204. The separator 212 may be a bladder or other flexible container pre-charged with a gas (e.g., nitrogen) to enable maintaining the pressure of the working fluid within the fluid chamber 216. In other embodiments, the biasing chamber 214 may be pre-charged with a gas. In still further embodiments, the biasing chamber 214 may instead include a spring or other mechanical biasing component. In any case, the pressure accumulator 208 may operate as a mechanical battery configured to enable supply (e.g., temporary supply) of pressurized working fluid from the fluid chamber 216 to the bearing assemblies 150 via the lubricant circuit 204, such as during periods of non-operation of the pump 206. For example, during an interruption in operation of the pump 206, the pressure accumulator 208 may discharge pressurized working fluid to the lubricant circuit 204 for supply to the bearing assemblies 150. In this way, the bearing assemblies 150 may continue to operate to support a load on the shaft 104 while operation of the pump 206 is restarted and / or while operation of the compressor 32 (e.g., the motor 50) is suspended in a controlled manner. In some embodiments, the pressure accumulator 208 may also operate to damp oscillations in the flow of pressurized working fluid directed to the bearing assemblies 150. Further, the pressure accumulator 208 may be configured to supply pressurized working fluid to the bearing assemblies 150 at startup of the vapor compression system 14 (e.g., prior to operation of the pump 206 and / or the compressor 32).

[0042] The fluid supply system 130 may also include other components disposed along the lubricant circuit 204, such as a check valve 218 disposed between the pump 206 and the pressure accumulator 208. The check valve 218 may be configured to close and block flow of liquid working fluid from the pump 206 and along toward the bearing assemblies 150 based on a pressure of the liquid working fluid discharged by the pump 206. For example, in response to a pressure of the liquid working fluid falling below a threshold value (e.g., a threshold value corresponding to a liquid working fluid pressure desired for supply to the bearing assemblies 150), the check valve 218 may close. In such instances, pressurized liquid working fluid stored within the pressure accumulator 208 may be supplied to the bearing assemblies 150 (e.g., with the closed check valve 218 blocking working fluid flow back to the pump 206) to enable at least temporary continued operation of the bearing assemblies 150 to support the shaft 104. The check valve 218 may be a ball check valve, a diaphragm check valve, a swing check valve, a stop-check valve, a lift-check valve, an in-line check valve, or any other suitable valve.

[0043] In some embodiments, the fluid supply system 130 may include a filter 220 disposed along the lubricant circuit 204 (e.g., downstream of the pressure accumulator 208 and upstream up the bearing assemblies 150). The filter 220 (e.g., may be configured to remove particulates and / or moisture (e.g., water, water vapor) from the liquid working fluid prior to the liquid working fluid being directed to the bearing assemblies 150.

[0044] As discussed above, the working fluid may be subcooled upstream of the pump 206 to reduce cavitation and flashing within the pump 206. To this end, the fluid supply system 130 may include a heat exchanger 222 disposed along the lubricant circuit 204. The heat exchanger 222 is disposed upstream of the pump 206 relative to the flow of working fluid through the lubricant circuit 204. The heat exchanger 222 may be a brazed-plate heat exchanger, a shell and tube heat exchanger, a double tube heat exchanger, a tube in tube heat exchanger, or any other suitable heat exchanger. It should be noted that while the condenser 34 and the evaporator 38 may include other heat exchangers, the heat exchanger 222 is disposed external to the condenser 34 and the evaporator 38. As such, the heat exchanger 222 may be arranged along the lubricant circuit 204 in parallel with the working fluid circuit 200 (e.g., the liquid line portion 202 extending between the condenser 34 and the evaporator 38). In operation, the heat exchanger 222 may subcool the working fluid directed from the liquid line portion 202 into the lubricant circuit 204. As a result, the vapor pressure (e.g., equilibrium vapor pressure) of the working fluid may be reduced, and the working fluid may remain in a liquid phase in the event that the flow of the working fluid experiences a pressure drop (e.g., upstream of, downstream of, or within the pump 206). In this way, subcooling of the working fluid may ensure that the working fluid supplied to the pump 206 is in a liquid phase, which may reduce undesired effects, such as flashing of the working fluid at the pump 206, cavitation of the pump 206, and so forth. The heat exchanger 222 is configured to place the working fluid drawn from the liquid line portion 202 in a heat exchange relationship with a cooling fluid 224 (e.g., auxiliary cooling fluid). In the illustrated embodiment, the cooling fluid 224 is directed from a cooling fluid source 226, such as a reservoir (e.g., a tank), to the heat exchanger 222 via a cooling fluid circuit 228 (e.g., a cooling fluid conduit). The cooling fluid 224 may be water, conditioning fluid, refrigerant, or another suitable fluid colder than the working fluid entering the heat exchanger 222 from the condenser 34. In some embodiments, the cooling fluid 224 may include fluid cooled by the vapor compression system 14, such as water cooled by the evaporator 38.

[0045] The cooling fluid circuit 228 may include a modulating valve 230 (e.g., globe valve, disc valve, ball valve, butterfly valve, etc.) configured to control the flow of the cooling fluid 224 into the heat exchanger 222. By adjusting a position of the modulating valve 230, a flow rate of the cooling fluid 224 through the heat exchanger 222 may be regulated. As a result, a rate of heat transfer between the cooling fluid 224 and the working fluid may be controlled. For example, the position of the modulating valve 230 may be selected from a continuous or discrete range of positions between fully closed and fully open (e.g., between 0 percent and 100 percent open). In this way, the modulating valve 230 may enable control of the temperature of the working fluid (e.g., a degree of subcooling) discharged by the heat exchanger 222.

[0046] The vapor compression system 14 may also include a controller 250 (e.g., a control system, control board, control panel) communicatively coupled to one or more components of the vapor compression system 14 and / or the bearing system 100 (e.g., fluid supply system 130). The controller 250 is configured to monitor, adjust, and / or otherwise control operation of the components of the vapor compression system 14 and / or the bearing system 100. For example, one or more control transfer 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 other components described herein. Such components may include a network interface that enables the components of the vapor compression system 14 and / or 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 the components of the vapor compression system 14 and / or bearing system 100 to communicate via mobile telecommunications technology, Bluetooth®, near-field communications technology, and the like.

[0047] In some embodiments, the controller 250 may include a portion 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 may be configured to control components of the vapor compression system 14 and / or the bearing system 100 in accordance with the techniques discussed herein. The controller 250 includes processing circuitry 252, such as one or more microprocessors, which may 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 (RISC) processors.

[0048] The controller 250 may also include a memory device 254 (e.g., a memory) that may store information such as instructions, control software, look up tables, configuration data, etc. The memory device 254 may include a volatile memory, such as random access memory (RAM), and / or a nonvolatile memory, such as read-only memory (ROM). The memory device 254 may store a variety of information and may be used for various purposes. For example, the memory device 254 may store processor-executable instructions including firmware or software for the processing circuitry 252 to execute, 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 may store machine-readable instructions for the processing circuitry 252 to execute. The memory device 254 may include ROM, flash memory, a hard drive, or any other suitable optical, magnetic, or solid-state storage medium, or a combination thereof. The memory device 254 may store data, instructions, and any other suitable data. It should be appreciated that the memory device 254 may store processor-executable instructions (e.g., for execution via the processing circuitry 252) to enable operation of any of the components described herein and to enable any of the functionalities and / or operations described herein.

[0049] The controller 250 may be configured to control operation of components of the vapor compression system 14 and / or the bearing system 100 (e.g., fluid supply system 130) based on detected operating parameters of the vapor compression system 14 and / or the bearing system 100. To this end, the vapor compression system 14 includes one or more sensors 256 configured to detect operating parameters associated with or indicative of operating conditions of the vapor compression system 14 and the bearing system 100. For example, one or more of the sensors 256 may be disposed along the lubricant circuit 204 and may be configured to detect operating parameters of the working fluid directed through the lubricant circuit 204, such as temperature, pressure, flow rate, and so forth. In some embodiments, one or more sensors 256 may be configured to detect an operating parameter associated with the motor 50, such as a rotational speed of the shaft 104, a torque on the shaft 104, a temperature of the motor 50, and so forth. One or more sensors 256 may be configured to detect an operating parameter of the bearing assemblies 150, such as a detection of whether one or more bearing assemblies 150 is in contact (e.g., physical contact) with the shaft 104, as described further below.

[0050] In some embodiments, one of the sensors 256 may be configured to detect an operating parameter associated with the pressure accumulator 208, such as a pressure of working fluid within the fluid chamber 216 and / or a pressure of gas within the biasing chamber 214. Additionally or alternatively, one or more of the sensors 256 may be configured to detect a liquid level of working fluid within the condenser 34, which may be referenced before and / or during startup of the bearing system 100 and / or vapor compression system 14. In some embodiments, one or more of the sensors 256 may be configured to detect an operating parameter of the pump 206, such as noise emitted by the pump 206, vibration of the pump 206, working fluid liquid and / or vapor presence within the pump 206, a speed of the pump 206, and so forth. As will be appreciated, each sensor 256 included in the vapor compression system 14 may be communicatively coupled to the controller 250. Thus, the controller 250 may receive data and / or feedback from the sensors 256 and may control operation of the vapor compression system 14 and / or the bearing system 100 based on the feedback and / or data.

[0051] The controller 250 may control the subcooling of the working fluid in the lubricant circuit 204 by controlling the flow of the cooling fluid 224 through the heat exchanger 222. For example, the controller 250 may cause the modulating valve 230 to modulate the flow rate of the cooling fluid 224 based on one or more operating parameters of the vapor compression system 14 in order to subcool the working fluid to a desired temperature. To this end, the controller 250 may receive feedback from the sensors 256 and control the modulating valve 230 based on the feedback. For example, the controller 250 may determine or receive data (e.g., sensor data) indicative of the operating parameters, which may include temperature, hydrostatic pressure, vapor pressure, mass / volumetric flow rate, heat transfer, phase, and / or bubbles of the working fluid and / or cooling fluid 224 at relevant locations of the vapor compression system 14 (e.g., in the lubricant circuit 204, in the pump 206, upstream of the pump 206, downstream of the pump 206, in the bearing assemblies 150, in the liquid line portion 202, in the cooling fluid circuit 228, in the heat exchanger 222). The operating parameters may also include nominal or measured parameters of the compressor 32, the evaporator 38, the condenser 34, and any other components of the vapor compression system 14. Based on these operating parameters, the controller 250 may control the position of the modulating valve 230 to cool the working fluid. That is, the controller 250 may receive feedback from the sensors 256 and control the modulating valve 230 based on the feedback.

[0052] Additionally, the operating parameters may include a power or speed of the pump 206. As conditions of the vapor compression system 14 change, the controller 250 may control the pump speed to pressurize the working fluid accordingly. For example, the pump 206 may operate at a first pump speed in a startup mode of the vapor compression system 14 and a second pump speed in a running mode. The pump 206 may be controlled based on feedback from the sensors 256 and / or any of the operating parameters discussed above. Additionally, the modulating valve 230 may be controlled based on the pump speed. For example, a tendency of the working fluid to cavitate or flash may correlate with the pump speed. Indeed, the pump speed may affect the vapor pressure of the working fluid, such that greater pump speeds may promote increased cavitation. As such, a greater degree of subcooling may be needed to prevent or reduce cavitation. Accordingly, the modulating valve 230 may be controlled based on the speed of the pump 206. In particular, the pump speed may be positively correlated to the flow rate of the cooling fluid 224 and inversely correlated to the temperature of the working fluid. In some embodiments, the controller 250 may coordinate control of the pump 206 and the modulating valve 230 to avoid cavitation of the working fluid. For example, the controller 250 may limit the pump speed based on the position of the modulating valve 230.

[0053] The controller 250 may determine the appropriate pump speed and or flow rate of the cooling fluid 224 based on a relationship between the pump speed and a corresponding temperature (e.g., threshold temperature) at which the working fluid would or may cavitate at the pump speed. That is, a suitable temperature of the working fluid may be a function of the pump speed, and the controller 250 may be configured to control the temperature of the working fluid based on the relationship. In some embodiments, the relationship may be determined empirically based on observable indicators of cavitation or flashing. For example, cavitation may produce an identifiable sound or vibration in the pump that may be heard by an operator or sensed using one of the sensors 256. During a testing phase, an operator may operate the pump 206 to pump the working fluid at various pump speeds and temperatures while listening for sounds of cavitation. By recording the pump speeds and temperatures at which cavitation is observed, a function or model of the relationship between threshold temperatures and pump speed may be determined. For example, the model may be a table listing a range of pump speeds associated with respective threshold temperatures. The table may be stored in the memory 254 of the controller 250, and the controller 250 may reference the table to determine the threshold temperature associated with a current pump speed and adjust the modulating valve 230 accordingly.

[0054] In other embodiments, the vapor compression system 14 may include a cavitation sensor 258 configured to detect cavitation in the pump 206. The cavitation sensor 258 may detect cavitation based on a detected sound or intensity of vibrations at the pump 206. For example, the cavitation sensor 258 may be a piezoelectric sensor configured to transmit a signal to the controller 250 in response to detecting vibrations indicative of cavitation. In this way, the controller 250 may use the cavitation sensor 258 data as feedback for controlling the flow rate of the cooling fluid 224 (e.g., a position of the modulating valve 230). For example, the controller 250 may determine, based on cavitation levels determined by the cavitation sensor 258, that the working fluid is above the threshold temperature and should be cooled further. Then, the controller 250 may adjust the modulating valve 230 to increase the flow rate of the cooling fluid 224, thereby increasing heat transfer from the working fluid to further cool the working fluid below the threshold temperature.

[0055] In addition to reducing and / or avoiding cavitation of the working fluid within the pump 206, subcooling the working fluid as described herein may enable sustained flow of liquid working fluid in the event of a loss of pressure in the lubricant circuit 204. For example, operation of the pump 206 may be interrupted (e.g., due to a loss of electrical power), or the fluid conduit 205 may experience a blockage or leakage. In some cases, the vapor compressions system 14 may perform a coast down operation to bring the shaft 104 to a controlled stop. When normal operation of the vapor compression system 14 is interrupted, the pressure accumulator 208 may temporarily supply pressurized working fluid to the bearing assemblies 150. However, the pressure provided by the pressure accumulator 208 may be insufficient to maintain the working fluid in a liquid state. For example, the pressure of the pressure accumulator 208 may decrease over time as the working fluid is discharged, causing the working fluid to vaporize (e.g., transition to a two-phase or vapor state) if the working fluid is above a threshold temperature. Under such circumstances, the subcooling of the working fluid provided by the heat exchanger 222 may enable the working fluid to remain in a liquid state during pressure drops. In this way, operation of the bearings may be at least temporarily sustained (e.g., in a coast down operation) in the event of an interruption of normal operation (e.g., pressure drop) of the vapor compression system 14.

[0056] FIG. 7 is a schematic of an embodiment of the vapor compression system 14, illustrating supply of the cooling fluid 224 by the evaporator 38 and directed through the heat exchanger 222 via the cooling fluid circuit 228. The cooling fluid 224 may be a portion of conditioning fluid, such as water, that transfers heat to the working fluid within the evaporator 38. Then, the cooling fluid 224, after being cooled by the evaporator 38, may be discharged from an outlet of the evaporator 38 and be directed to flow through the heat exchanger 222, whereupon the cooling fluid 224 may absorb heat from the working fluid in the lubricant circuit 204. The cooling fluid 224, heated via the heat exchanger 222, may flow from the heat exchanger 222 back to the evaporator 38 to be cooled again. As discussed above, the cooling fluid circuit 228 may include the modulating valve 230 configured to modulate the flow of the cooling fluid 224 through the heat exchanger 222, thereby controlling a degree to which the working fluid is subcooled.

[0057] FIG. 8 is a schematic of an embodiment of the vapor compression system 14, illustrating the cooling fluid 224 as a portion of conditioning fluid 260 (e.g., water) routed to the load 62. As discussed above with respect to FIG. 3, the working fluid may absorb heat from (e.g., cool) the conditioning fluid 260 that is subsequently used to cool the load 62 (e.g., the building 12 of FIG. 1). For example, the conditioning fluid 260 may be cooled by the working fluid in the evaporator 38, and then may be utilized in the building 12 of FIG. 1 to condition an air flow provided to condition a space in the building 12. The conditioning fluid 260 may flow from the evaporator 38 to the load 62 via the supply line 60S. Additionally, a portion of the conditioning fluid 260 may flow (e.g., from the evaporator 38 or from the supply line 60S) to the heat exchanger 222 via the cooling fluid circuit 228 to cool the working fluid in the lubricant circuit 204. Subsequently, the cooling fluid 224, heated by the working fluid via the heat exchanger 222, may flow from the heat exchanger 222 to the evaporator 38. In some embodiments, a return flow of the cooling fluid 224 may join a return flow of the conditioning fluid 260 from the load 62 via the return line 60R.

[0058] FIG. 9 is a schematic of an embodiment of the vapor compression system 14, illustrating the cooling fluid 224 as a portion of the working fluid drawn from the condenser 34. Of the working fluid exiting the condenser 34, a first portion 262 (e.g., first flow) may flow through the lubricating circuit 204 toward the bearings, and a second portion 264 (e.g., second flow) may flow through the cooling fluid circuit 228 as the cooling fluid 224. The cooling fluid 224 (e.g., the second portion 264) may flow through an expansion device 266 (e.g., additional expansion device, expansion valve, thermal expansion valve [TXV]) configured to control the flow rate of the cooling fluid 224 into the heat exchanger 222. In particular, the expansion device 266 may restrict the flow of the cooling fluid 224 and reduce the pressure and / or temperature of the cooling fluid 224 downstream of the expansion device 266. As a result, the cooling fluid 224 may vaporize (e.g., flash) as it enters the heat exchanger 222. As a sensible heat of the cooling fluid 224 is converted to latent heat due to vaporization of the cooling fluid 224, the working fluid in the lubricant circuit 204 (e.g., first portion 262) may transfer heat to the cooling fluid 224 (e.g., second portion 264). In this way, the second portion 264 of the working fluid may subcool the first portion 262 of the working fluid via the heat exchanger 222. The first portion 262 of the working fluid, subcooled by the cooling fluid 224, may be pumped by the pump 206 toward the bearings of the compressor 32. The cooling fluid 224, heated by the first portion 262, may flow back into the working fluid circuit 200 to be condensed back into a liquid working fluid. For example, the cooling fluid 224 may exit the heat exchanger 222 and join a flow of the working fluid into an inlet of the compressor 32. In this way, the cooling fluid circuit may direct the second portion 264 of the working fluid from the heat exchanger 222 to the inlet (e.g., suction inlet 112) of the compressor 32.

[0059] While only certain features and embodiments have been illustrated and described, many modifications and changes may occur to those skilled in the art, such as variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, such as temperatures and pressures, mounting arrangements, use of materials, colors, orientations, and so forth, without materially 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 re-sequenced according to alternative embodiments. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the disclosure.

[0060] Furthermore, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not have been described, such as those unrelated to the presently contemplated best mode, or those unrelated to enablement. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, without undue experimentation.

[0061] The techniques presented and claimed herein are referenced and applied to material objects and concrete examples of a practical nature that demonstrably improve the present technical field and, as such, are not abstract, intangible or purely theoretical. Further, if any claims appended to the end of this specification contain one or more elements designated as “means for [perform]ing [a function] . . . ” or “step for [perform]ing [a function] . . . ”, it is intended that such elements are to be interpreted under 35 U.S.C. 112(f). However, for any claims containing elements designated in any other manner, it is intended that such elements are not to be interpreted under 35 U.S.C. 112(f).

Examples

Embodiment Construction

[0018]One or more specific embodiments will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated 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 developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

[0019]When introducing elements of various embodiments of the present disclosure, the articles “a,”“an,” and “the” are intended to mean that there are one or more of the elements....

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from and the benefit of U.S. Provisional Application No. 63 / 538,463, entitled “FLUID SUPPLY SYSTEM FOR BEARINGS OF HVAC&R SYSTEM,” filed Sep. 14, 2023, and U.S. Provisional Application No. 63 / 443,921, entitled “BEARING SYSTEM FOR HVAC&R SYSTEM,” filed Feb. 7, 2023, each of which is hereby incorporated by reference in its entirety for all purposes.BACKGROUND

[0002] This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are 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. Accordingly, it should be understood that these statements are to 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 phases between vapor, liquid, and combinations thereof in response to exposure to different temperatures and pressures within components of the chiller system. The chiller system may place the working fluid in a heat exchange relationship with a conditioning fluid (e.g., water) and may deliver the conditioning fluid to conditioning equipment and / or a conditioned environment serviced by the chiller system. In such applications, the conditioning fluid may be directed through downstream equipment, such as air handlers, to condition other fluids, such as air in a building. The chiller system may include a compressor configured to pressurize the working fluid and circulate the working fluid through a working fluid circuit of the chiller system. In some applications, a shaft of the compressor may be driven in rotation by a motor in order to drive rotation of an impeller of the compressor that pressurizes the working fluid. Traditionally, the compressor includes bearings configured to facilitate rotation of the shaft. Unfortunately, existing bearings utilized with compressors may be complex, expensive, and / or may contribute to inefficiencies in operation of the chiller system.SUMMARY

[0004] A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below.

[0005] In one embodiment, a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system includes a working fluid circuit including an evaporator, a condenser, and a compressor. The HVAC&R system also includes a fluid supply system including a lubricant circuit configured to direct a flow of working fluid from the working fluid circuit to a bearing of the compressor. The lubricant circuit includes a heat exchanger configured to place the flow of working fluid in a heat exchange relationship with a cooling fluid.

[0006] In another embodiment, a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system, includes a working fluid circuit including a condenser, an evaporator, and a compressor. The working fluid circuit is configured to circulate a working fluid therethrough. The HVAC&R system also includes a lubricant circuit configured to direct a portion of the working fluid from the working fluid circuit to a bearing of the compressor. Additionally, the HVAC&R system includes a heat exchanger disposed along the lubricant circuit between the working fluid circuit and the bearing, relative to a flow direction of the portion of the working fluid along the lubricant circuit. Furthermore, the HVAC&R system includes a cooling fluid circuit configured to circulate a cooling fluid through the heat exchanger. The heat exchanger is configured to facilitate heat transfer from the portion of the working fluid to the cooling fluid. Additionally, the HVAC&R system includes a pump disposed along the lubricant circuit and configured to direct the flow of working fluid from the heat exchanger to the bearing.

[0007] In another embodiment, a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system includes a condenser disposed along a working fluid circuit. The HVAC&R system also includes a compressor disposed along the working fluid circuit, wherein the compressor comprises a bearing. Furthermore, the HVAC&R system includes a heat exchanger of a lubricant circuit. The heat exchanger is configured to receive a flow of working fluid from the condenser and to place the flow of working fluid in a heat exchanger relationship with a cooling fluid. The lubricant circuit is configured to direct the flow of working fluid from the heat exchanger to the bearing.DRAWINGS

[0008] Various aspects of this disclosure may be better understood upon reading the following detailed description and upon reference to the drawings in which:

[0009] FIG. 1 is a perspective view of an embodiment of a building that may utilize a heating, ventilating, air conditioning, and / or refrigeration (HVAC&R) system in a commercial setting, in accordance with an aspect of the present disclosure;

[0010] FIG. 2 is a perspective view of an embodiment of a vapor compression system, in accordance with an aspect of the present disclosure;

[0011] FIG. 3 is a schematic of an embodiment of a vapor compression system, in accordance with an aspect of the present disclosure;

[0012] FIG. 4 is a schematic of an embodiment of a vapor compression system, in accordance with an aspect of the present disclosure;

[0013] FIG. 5 is a cross-sectional side view of an embodiment of a compressor of a vapor compression system, illustrating a bearing system of the compressor, in accordance with an aspect of the present disclosure;

[0014] FIG. 6 is a schematic of an embodiment of a vapor compression system including a fluid supply system of a bearing system for a compressor, in accordance with an aspect of the present disclosure;

[0015] FIG. 7 is a schematic of an embodiment of a vapor compression system including a fluid supply system of a bearing system for a compressor, in accordance with an aspect of the present disclosure;

[0016] FIG. 8 is a schematic of an embodiment of a vapor compression system including a fluid supply system of a bearing system for a compressor, in accordance with an aspect of the present disclosure; and

[0017] FIG. 9 is a schematic of an embodiment of a vapor compression system including a fluid supply system of a bearing system for a compressor, in accordance with an aspect of the present disclosure.DETAILED DESCRIPTION

[0018] One or more specific embodiments will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated 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 developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

[0019] When introducing elements of various embodiments of the present disclosure, the articles “a,”“an,” and “the” are intended to mean that there are one or more of the 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. Additionally, 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.

[0020] As used herein, the terms “approximately,”“generally,” and “substantially,” and so forth, are intended to convey that the property value being described may be within a relatively small range of the property value, as those of ordinary skill would understand. For example, when a property value is described as being “approximately” equal to (or, for example, “substantially similar” to) a given value, this is intended to mean that the property value may be within + / −5%, within + / −4%, within + / −3%, within + / −2%, within + / −1%, or even closer, of the given value. Similarly, when a given feature is described as being “substantially parallel” to another feature, “generally perpendicular” to another feature, and so forth, this is intended to mean that the given feature is within + / −5%, within + / −4%, within + / −3%, within + / −2%, within + / −1%, or even closer, to having the described nature, such as being parallel to another feature, being perpendicular to another feature, and so forth. Further, it should be understood that mathematical terms, such as “planar,”“slope,”“perpendicular,”“parallel,” and so forth are intended to encompass features of surfaces or elements as understood to one of ordinary skill in the relevant art, and should not be rigidly interpreted as might be understood in the mathematical arts. For example, a “planar” surface is intended to encompass a surface that is machined, molded, or otherwise formed to be substantially flat or smooth (within related 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., incline) with respect to a point of reference using techniques and tools available to one of ordinary skill in the art.

[0021] Embodiments of the present disclosure relate to a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system (e.g., a chiller) including a vapor compression system (e.g., vapor compression circuit) having a compressor. In operation, the compressor may pressurize a working fluid within the vapor compression system and direct the working fluid to a condenser (e.g., a first heat exchanger), which may cool and condense the working fluid. The condensed working fluid may be directed to an expansion device, which may reduce a pressure of the working fluid, further cooling the working fluid. From the expansion device, the cooled working fluid may be directed to an evaporator (e.g., a second heat exchanger), where the working fluid may be placed in a heat exchange relationship with a conditioning fluid to cool the conditioning fluid. The conditioning fluid may be circulated between the evaporator and a structure, such as a building, where the conditioning fluid is used to cool an air flow delivered to a conditioned space of the structure. In some embodiments, an air handling unit (AHU) of the HVAC&R system may receive the conditioning fluid from the chiller and utilize the conditioning fluid to cool the air flow delivered to the conditioned space. The conditioning fluid may then be returned to the evaporator to be cooled again.

[0022] In some embodiments, the compressor may include a bearing system including bearings (e.g., hydrostatic bearings) that utilize a pressurized fluid to support and lubricate a rotating shaft of the compressor. For example, the working fluid may be a refrigerant, and the bearing system may include a lubricant circuit extending from the working fluid circuit and direct a portion of the working fluid from the working fluid circuit into the bearings of the compressor. That is, the portion of the working fluid in the lubricant circuit may be utilized as a lubricating fluid. The lubricant circuit may include a pump configured to pump the working fluid toward the bearings of the compressor. In accordance with present techniques, the bearings may receive the working fluid in a liquid phase and may discharge the working fluid toward the rotating shaft in a gaseous phase. In this way, the working fluid, which is configured to exchange heat with the conditioning fluid as part of the working fluid circuit, may also be utilized to enable the bearings to support (e.g., levitate) the shaft of the compressor and enable rotation of the shaft.

[0023] It may be desirable to maintain the supply of the working fluid to the bearings at a suitable pressure level. For example, a threshold pressure of the working fluid may be demanded for the bearings to effectively lubricate and / or support the shaft of the compressor. To pressurize the working fluid, the pump may be configured to operate at a desired speed. However, in addition to the pump speed, the pressure of pumped working fluid may depend on a temperature and phase of the working fluid. For example, the pump may receive the working fluid in a liquid phase, such as from the condenser of the working fluid circuit. Then, changes in pressure may cause the working fluid to cavitate or vaporize (e.g., flash) within the pump and / or the lubricant circuit. As a result, the pressure of the pumped working fluid may be reduced, which may impede bearing performance in some instances. Additionally, cavitation of the working fluid may cause undesirable wear to the pump and other components of the lubricant circuit. Therefore, improved fluid supply systems for compressor bearings are desired.

[0024] Accordingly, present embodiments are directed to a fluid supply system configured to direct subcooled working fluid, such as from a condenser of a working fluid circuit, to a bearing system of a compressor disposed along the working fluid circuit. In particular, fluid supply systems described herein include a heat exchanger configured to cool working fluid directed from the condenser to a pump. For example, the heat exchanger may enable transfer of heat from the working fluid to a cooling fluid, such that the working fluid becomes subcooled to a desired temperature (e.g., a temperature corresponding to the pump speed). In this way, the working fluid may remain in a liquid phase as the pump drives flow of the working fluid toward the bearings of the compressor. As the pump speed varies, the rate of heat transfer between the working fluid and the cooling fluid may be varied to provide a corresponding degree of subcooling. For example, a valve may modulate the flow rate of the cooling fluid through the heat exchanger. Moreover, the flow rate of the cooling fluid may be controlled based on a temperature, pressure, and / or flow rate of the working fluid (e.g., within the lubricant circuit). Additionally, a controller may control the flow of cooling fluid through the heat exchanger, and thereby control an amount of heat transfer between the working fluid and the cooling fluid, such as based on vibrations or sounds caused by cavitation within the pump. As a result, the working fluid may be pumped toward the bearings of the compressor at a desired pressure, temperature, and / or phase suitable for operation of the bearings. Moreover, the subcooling of the working fluid may ensure that the working fluid reaches the bearings in a liquid state, even if the working fluid flow experiences a pressure drop (e.g., during a coast-down operation or an interruption of the pump) during flow to the bearings. In this way, present embodiments provide a fluid supply system configured to maintain a desired, pressurized flow of working fluid to a bearing system, thereby mitigating wear and degradation to components of the bearing system and the compressor.

[0025] Turning now to the drawings, FIG. 1 is a perspective view of an embodiment of a heating, ventilating, air conditioning, and / or refrigeration (HVAC&R) system 10 in a building 12 for a typical commercial setting. The HVAC&R system may include a vapor compression system 14 to supply chilled liquid to cool the building 12 and a boiler 16 to supply warm liquid to heat the building 12. The vapor compression system 14, also referred to herein as a chiller, may circulate a working fluid (e.g., refrigerant) that is cooled by a cooling fluid (e.g., liquid such as water) in a condenser of the vapor compression system 14, and that is heated by a conditioning fluid (e.g., liquid, such as water) in an evaporator of the vapor compression system 14. The cooling fluid may be provided by a cooling tower which cools the cooling fluid via, for example, ambient air. The conditioning fluid, cooled by the working fluid as noted above, may be utilized to cool an air flow provided to conditioned spaces of the building 12.

[0026] The HVAC&R system 10 may also include an air distribution system which circulates air through the building 12. The air distribution system can also include an air return duct 18, an air supply duct 20, and / or an air handler 22. In some embodiments, the air handler 22 may include a heat exchanger that is connected to the boiler 16 and the vapor compression system 14 by conduits 24. The heat exchanger in the air handler 22 may receive either heated liquid from the boiler 16 or the conditioning fluid (e.g., chilled liquid such as water) from the vapor compression system 14, depending on the mode of operation of the HVAC&R system 10. The HVAC&R system 10 is shown with a separate air handler on each floor of 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

[0027] FIGS. 2 and 3 illustrate embodiments of the vapor compression system 14, or chiller, which can be used in the HVAC&R system 10. The vapor compression system 14 may circulate a working fluid through a circuit (e.g., working fluid circuit) starting with a compressor 32, such as a centrifugal compressor. The circuit may also include a condenser 34, an expansion valve(s) or device(s) 36, and an evaporator 38. The vapor compression system 14 may further include a control panel 40 that has an analog to digital (A / D) converter 42, a microprocessor 44, a non-volatile memory 46, and / or an interface board 48.

[0028] Some examples of fluids that may be used as working fluids in the vapor compression system 14 are hydrofluorocarbon (HFC) based refrigerants, for example, R-410A, R-407, R-134a, hydrofluoro olefin (HFO), “natural” refrigerants like ammonia (NH3), R-717, carbon dioxide (CO2), R-744, or hydrocarbon-based refrigerants, water vapor, or any other suitable working fluid. Other possible working fluids include R-123, R-514A, R-1130yd, R-1233zd, R-134a, R-1142ze, R-1142yf, R-1311, R-32, and R-410A. In some embodiments, the vapor compression system 14 may be configured to efficiently utilize working fluids having a normal boiling point of about 19 degrees Celsius (66 degrees Fahrenheit) at one atmosphere of pressure, also referred to as low pressure refrigerants, versus a medium pressure working fluid, such as R-134a. As used herein, “normal boiling point” may refer to a boiling point temperature measured at one atmosphere of pressure.

[0029] In some embodiments, the vapor compression system 14 may use one or more of a variable speed drive (VSDs) 52, a motor 50, the compressor 32, the condenser 34, the expansion valve or device 36, and / or the evaporator 38. The motor 50 may drive the compressor 32 during a normal operating mode and may be powered by a variable speed drive (VSD) 52. The VSD 52 receives alternating current (AC) power during the normal operating mode, where the AC power includes a particular fixed line voltage and fixed line frequency from an AC power source, and provides power having a variable voltage and frequency to the motor 50. In other embodiments, the motor 50 may be powered directly from an AC or direct current (DC) power source. The 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 motor.

[0030] The compressor 32 compresses a working fluid vapor and delivers the vapor to the condenser 34 through a discharge passage. In some embodiments, the compressor 32 may be a centrifugal compressor. The working fluid vapor delivered by the compressor 32 to the condenser 34 may transfer heat to a cooling fluid (e.g., water or air) in the condenser 34. The working fluid vapor may condense to a working fluid liquid in the condenser 34 as a result of thermal heat transfer with the cooling fluid. The liquid working fluid from the condenser 34 may flow through the expansion device 36 to the evaporator 38. In the illustrated embodiment of FIG. 3, the condenser 34 is water cooled and includes a tube bundle 54 connected to a cooling tower 56, which supplies the cooling fluid to the condenser 34.

[0031] The liquid working fluid delivered to the evaporator 38 may absorb heat from a conditioning fluid that is subsequently routed to a load 62 (e.g., the building 12 of FIG. 1). For example, the conditioning fluid may be cooled by the working fluid in the evaporator 38, and then may be utilized in the building 12 of FIG. 1 to condition an air flow provided to condition a space in the building 12. The liquid working fluid in the evaporator 38 may undergo a phase change from the liquid working fluid to a working fluid vapor. As shown in the illustrated embodiment of FIG. 3, 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. 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 return line 60R and exits the evaporator 38 via supply line 60S. The evaporator 38 may reduce the temperature of the conditioning fluid in the tube bundle 58 via thermal heat transfer with the working fluid. The tube bundle 58 in the evaporator 38 can include a plurality of tubes and / or a plurality of tube bundles. In any case, the vapor working fluid exits the evaporator 38 and returns to the compressor 32 by a suction line to complete the cycle.

[0032] FIG. 4 is a schematic of an embodiment of the vapor compression system 14 with an intermediate circuit 64 incorporated between the condenser 34 and the expansion device 36. The intermediate circuit 64 may have an inlet line 68 that is directly fluidly connected to the condenser 34. In other embodiments, the inlet line 68 may be indirectly fluidly coupled to the condenser 34. As shown in the illustrated embodiment of FIG. 4, 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 tank (e.g., a flash intercooler). In other embodiments, the intermediate vessel 70 may be configured as a heat exchanger or a “surface economizer.” In the illustrated embodiment of FIG. 4, the intermediate vessel 70 is used as a flash tank, and the first expansion device 66 is configured to lower 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 for further expansion of the liquid working fluid due to a pressure drop experienced by the liquid working fluid when entering the intermediate vessel 70 (e.g., due to a rapid increase in volume experienced when entering the intermediate vessel 70). The vapor working fluid in the intermediate vessel 70 may be drawn by the compressor 32 through a suction line 74 of the compressor 32. In other embodiments, the vapor working fluid in the intermediate vessel 70 may be drawn to an intermediate stage of the compressor 32 (e.g., not the suction stage). The liquid working fluid that collects in the intermediate vessel 70 may be at a lower enthalpy than the liquid working fluid exiting the condenser 34 due to expansion of the working fluid at the expansion device 66 and / or in the intermediate vessel 70. The liquid working fluid from intermediate vessel 70 may then flow through line 72 and through a second expansion device 36 to the evaporator 38.

[0033] In accordance with present embodiments, the compressor 32 may be a centrifugal compressor (e.g., a hermetic compressor) having a levitated rotor or shaft. To this end, the vapor compression system 14 includes a bearing system with one or more bearings configured to support a load of the shaft of the compressor 32. The bearing system is configured to direct a pressurized fluid (e.g., liquid, working fluid, refrigerant) through the bearings, and the bearings are configured to discharge the fluid toward and against the shaft in order to enable levitation 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 the pressurized fluid toward the shaft within a housing of the compressor 32. In this way, the bearing system may support a 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 may be a working fluid (e.g., refrigerant) circulated through the vapor compression system 14. Thus, the vapor compression system 14 may not utilize a dedicated lubricant, such as oil, to support and enable rotation of the shaft of the compressor 32. Further, the bearing system may be incorporated with the vapor compression system 14 at reduced costs, as compared to other existing bearing system designs. The disclosed embodiments also enable improved (e.g., simplified) control of the bearing system, as well as more efficient operation of the vapor compression system 14.

[0034] With the foregoing in mind, FIG. 5 is a cross-sectional side view of an embodiment of the compressor 32 including a bearing system 100, in accordance with 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, such as 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 rotation of the impeller 106. Rotation of the impeller 106 may drive a working fluid (e.g., refrigerant) to flow through a working fluid flow path 110 (e.g., from the evaporator 38, from the intermediate vessel 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 onto the working fluid and discharge the working fluid to a diffuser passage 114 of the compressor 32. The working fluid may be directed from the diffuser passage 114 to a volute 116 of the compressor 32 and from the volute 116 to a condenser (e.g., the condenser 34) for heat exchange with a fluid, such as a cooling fluid.

[0035] In the illustrated embodiment, the compressor 32 (e.g., bearing system 100) includes a first bearing 118 (e.g., a radial bearing, bearing assembly, porous bearing) and a second bearing 120 (e.g., a radial bearing, bearing assembly, porous bearing) configured to control and / or adjust a position (e.g., radial position) of the shaft 104 relative to an axis 122 (e.g., rotational axis, central axis) of the shaft 104. For example, the first bearing 118 and the second bearing 120 may be configured to support a load of the shaft 104, such that the shaft 104 levitates within the first bearing 118 and the second bearing 120. The first bearing 118 and the second bearing 120 may also be configured to block movement (e.g., bending, radial movement, eccentric rotation) of the shaft 104 crosswise to the axis 122. The compressor 32 (e.g., bearing system 100) further includes a third bearing 124 (e.g., thrust bearing, axial bearing, bearing assembly, porous bearing) configured to control and / or adjust a position (e.g., axial position) of the shaft 104 along the axis 122. For example, the third bearing 124 may be configured to block or limit movement (e.g., translation) of the shaft 104 along the axis 122.

[0036] As mentioned above, the bearing system 100 is configured to direct a pressurized fluid to 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) circulated through the vapor compression system 14 having the compressor 32. However, it should be appreciated 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 received pressurized fluid and direct the pressurized fluid towards the shaft 104 to establish a high-pressure fluid film (e.g., vapor film) about the shaft 104 between the first bearing 118 and the second bearing 120 and the shaft 104. In this way, the pressurized fluid may cause the shaft 104 to levitate from the first bearing 118 and the second bearing 120, thereby enabling desired rotation of the shaft 104 about the axis 122. The one or more porous elements 126 of the third bearing 124 may receive pressurized fluid and direct the pressurized fluid towards a collar 128 (e.g., thrust collar) of the third bearing 124. In this way, the pressurized fluid may apply a force to the collar 128 and enable adjustable positioning of the shaft 104 along the axis 122.

[0037] The bearing system 100 includes a fluid supply system 130 configured to supply pressurized fluid to the bearings (first bearing 118, second bearing 120, and / or third bearing 124) of the bearing system 100. 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. An additional bearing housing 132 may be utilized with the third bearing 124. In other embodiments, the second bearing 120 and the third bearing 124 may be packaged together in a common bearing housing 132. The pressurized fluid may be directed through the bearing housings 132 to the corresponding porous elements 126 retained within each bearing housing 132. The fluid supply system 130 is described in further detail below. It should be appreciated that the compressor 32 may include any suitable number or type (e.g., radial, axial) of bearings incorporating the present techniques, and the bearings may be positioned at any suitable location within the housing 102 of the compressor 32.

[0038] FIG. 6 is a schematic of an embodiment of the vapor compression system 14 (e.g., HVAC&R system) including the bearing system 100 for the compressor 32. The vapor compression system 14 includes elements similar to those discussed above, including the compressor 32, the motor 50, the condenser 34, and the evaporator 38 (e.g., falling film evaporator) arranged along a working fluid circuit 200 (e.g., refrigerant circuit). Working fluid (e.g., refrigerant) may flow from an outlet of the condenser 34 toward the evaporator 38 via a liquid line portion 202 of the vapor compression system 14. Although the liquid line portion 202 is nominally configured to direct liquid working fluid (e.g., liquid refrigerant) from the condenser 34 to the evaporator 38, the working fluid in the liquid line portion 202 may include working fluid in other states, such as vapor or mixed vapor. For example, the liquid line portion 202 may include gaseous working fluid during certain operating conditions of the vapor compression system 14, such as a startup state or a coast-down state. Additionally, the pressure of the working fluid in the liquid line portion 202 may vary, based on an operating condition or parameter of the vapor compression system 14, or based on the state (e.g., phase, temperature) of the working fluid. For example, the pressure in the liquid line portion 202 may be less than a pressure of fluid delivered to the bearings.

[0039] In accordance with present techniques, the bearing system 100 also includes the fluid supply system 130 configured to direct pressurized fluid to the bearings (e.g., first bearing 118) of the bearing system 100. In particular, the fluid supply system 130 is configured to direct a portion of the working fluid (e.g., refrigerant) circulated through the working fluid circuit 200 to the bearing assemblies 150. To this end, the fluid supply system 130 includes a lubricant circuit 204 (e.g., fluid supply circuit) extending from the working fluid circuit 200 to the bearing assemblies 150 via a fluid conduit 205.

[0040] In the illustrated embodiment, the lubricant circuit 204 extends from the liquid line portion 202 of the working fluid circuit 200 to the bearing assemblies 150. Various components are disposed along the lubricant circuit 204 and are configured to enable desirable supply of the working fluid to the bearing assemblies 150 to enable the bearing assemblies 150 to support a load of the shaft 104 of the compressor 32. For example, the fluid supply system 130 includes a pump 206 (e.g., liquid pump) disposed along the lubricant circuit 204 and configured to direct flow of the working fluid (e.g. liquid working fluid) along the lubricant circuit 204 from the liquid line portion 202 of the working fluid circuit 200 to the bearing assemblies 150 of the motor 50 (e.g., compressor 32). The pump 206 may be a linear piston pump, in some embodiments, and the pump 206 may be driven electrically, pneumatically, mechanically, electromechanically, and / or via another suitable technique. In some embodiments, the pump 206 may operate without utilizing oil or other dedicated lubricant.

[0041] The fluid supply system 130 also includes a pressure accumulator 208 fluidly coupled to the lubricant circuit 204. The pressure accumulator 208 is fluidly coupled to the lubricant circuit 204 downstream of the pump 206 relative to a flow of working fluid along the lubricant circuit 204. Thus, the pressure accumulator 208 may receive a pressurized flow of working fluid (e.g., liquid working fluid, vapor working fluid, or both) from the pump 206 and the lubricant circuit 204. As will be appreciated, the pressure accumulator 208 is configured to store pressurized working fluid therein. For example, the pressure accumulator 208 may include a vessel 210 and a separator 212 (e.g., bladder, diaphragm, piston, etc.) disposed therein. In some embodiments, the separator 212 may divide an internal volume of the vessel 210 into a biasing chamber 214 (e.g., gas chamber) on a first side of the separator 212 and a fluid chamber 216 (e.g., liquid chamber, working fluid chamber) on a second side the separator 212. The fluid chamber 216 of the pressure accumulator 208 is configured to receive pressurized working fluid from the lubricant circuit 204. The separator 212 may be a bladder or other flexible container pre-charged with a gas (e.g., nitrogen) to enable maintaining the pressure of the working fluid within the fluid chamber 216. In other embodiments, the biasing chamber 214 may be pre-charged with a gas. In still further embodiments, the biasing chamber 214 may instead include a spring or other mechanical biasing component. In any case, the pressure accumulator 208 may operate as a mechanical battery configured to enable supply (e.g., temporary supply) of pressurized working fluid from the fluid chamber 216 to the bearing assemblies 150 via the lubricant circuit 204, such as during periods of non-operation of the pump 206. For example, during an interruption in operation of the pump 206, the pressure accumulator 208 may discharge pressurized working fluid to the lubricant circuit 204 for supply to the bearing assemblies 150. In this way, the bearing assemblies 150 may continue to operate to support a load on the shaft 104 while operation of the pump 206 is restarted and / or while operation of the compressor 32 (e.g., the motor 50) is suspended in a controlled manner. In some embodiments, the pressure accumulator 208 may also operate to damp oscillations in the flow of pressurized working fluid directed to the bearing assemblies 150. Further, the pressure accumulator 208 may be configured to supply pressurized working fluid to the bearing assemblies 150 at startup of the vapor compression system 14 (e.g., prior to operation of the pump 206 and / or the compressor 32).

[0042] The fluid supply system 130 may also include other components disposed along the lubricant circuit 204, such as a check valve 218 disposed between the pump 206 and the pressure accumulator 208. The check valve 218 may be configured to close and block flow of liquid working fluid from the pump 206 and along toward the bearing assemblies 150 based on a pressure of the liquid working fluid discharged by the pump 206. For example, in response to a pressure of the liquid working fluid falling below a threshold value (e.g., a threshold value corresponding to a liquid working fluid pressure desired for supply to the bearing assemblies 150), the check valve 218 may close. In such instances, pressurized liquid working fluid stored within the pressure accumulator 208 may be supplied to the bearing assemblies 150 (e.g., with the closed check valve 218 blocking working fluid flow back to the pump 206) to enable at least temporary continued operation of the bearing assemblies 150 to support the shaft 104. The check valve 218 may be a ball check valve, a diaphragm check valve, a swing check valve, a stop-check valve, a lift-check valve, an in-line check valve, or any other suitable valve.

[0043] In some embodiments, the fluid supply system 130 may include a filter 220 disposed along the lubricant circuit 204 (e.g., downstream of the pressure accumulator 208 and upstream up the bearing assemblies 150). The filter 220 (e.g., may be configured to remove particulates and / or moisture (e.g., water, water vapor) from the liquid working fluid prior to the liquid working fluid being directed to the bearing assemblies 150.

[0044] As discussed above, the working fluid may be subcooled upstream of the pump 206 to reduce cavitation and flashing within the pump 206. To this end, the fluid supply system 130 may include a heat exchanger 222 disposed along the lubricant circuit 204. The heat exchanger 222 is disposed upstream of the pump 206 relative to the flow of working fluid through the lubricant circuit 204. The heat exchanger 222 may be a brazed-plate heat exchanger, a shell and tube heat exchanger, a double tube heat exchanger, a tube in tube heat exchanger, or any other suitable heat exchanger. It should be noted that while the condenser 34 and the evaporator 38 may include other heat exchangers, the heat exchanger 222 is disposed external to the condenser 34 and the evaporator 38. As such, the heat exchanger 222 may be arranged along the lubricant circuit 204 in parallel with the working fluid circuit 200 (e.g., the liquid line portion 202 extending between the condenser 34 and the evaporator 38). In operation, the heat exchanger 222 may subcool the working fluid directed from the liquid line portion 202 into the lubricant circuit 204. As a result, the vapor pressure (e.g., equilibrium vapor pressure) of the working fluid may be reduced, and the working fluid may remain in a liquid phase in the event that the flow of the working fluid experiences a pressure drop (e.g., upstream of, downstream of, or within the pump 206). In this way, subcooling of the working fluid may ensure that the working fluid supplied to the pump 206 is in a liquid phase, which may reduce undesired effects, such as flashing of the working fluid at the pump 206, cavitation of the pump 206, and so forth. The heat exchanger 222 is configured to place the working fluid drawn from the liquid line portion 202 in a heat exchange relationship with a cooling fluid 224 (e.g., auxiliary cooling fluid). In the illustrated embodiment, the cooling fluid 224 is directed from a cooling fluid source 226, such as a reservoir (e.g., a tank), to the heat exchanger 222 via a cooling fluid circuit 228 (e.g., a cooling fluid conduit). The cooling fluid 224 may be water, conditioning fluid, refrigerant, or another suitable fluid colder than the working fluid entering the heat exchanger 222 from the condenser 34. In some embodiments, the cooling fluid 224 may include fluid cooled by the vapor compression system 14, such as water cooled by the evaporator 38.

[0045] The cooling fluid circuit 228 may include a modulating valve 230 (e.g., globe valve, disc valve, ball valve, butterfly valve, etc.) configured to control the flow of the cooling fluid 224 into the heat exchanger 222. By adjusting a position of the modulating valve 230, a flow rate of the cooling fluid 224 through the heat exchanger 222 may be regulated. As a result, a rate of heat transfer between the cooling fluid 224 and the working fluid may be controlled. For example, the position of the modulating valve 230 may be selected from a continuous or discrete range of positions between fully closed and fully open (e.g., between 0 percent and 100 percent open). In this way, the modulating valve 230 may enable control of the temperature of the working fluid (e.g., a degree of subcooling) discharged by the heat exchanger 222.

[0046] The vapor compression system 14 may also include a controller 250 (e.g., a control system, control board, control panel) communicatively coupled to one or more components of the vapor compression system 14 and / or the bearing system 100 (e.g., fluid supply system 130). The controller 250 is configured to monitor, adjust, and / or otherwise control operation of the components of the vapor compression system 14 and / or the bearing system 100. For example, one or more control transfer 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 other components described herein. Such components may include a network interface that enables the components of the vapor compression system 14 and / or 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 the components of the vapor compression system 14 and / or bearing system 100 to communicate via mobile telecommunications technology, Bluetooth®, near-field communications technology, and the like.

[0047] In some embodiments, the controller 250 may include a portion 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 may be configured to control components of the vapor compression system 14 and / or the bearing system 100 in accordance with the techniques discussed herein. The controller 250 includes processing circuitry 252, such as one or more microprocessors, which may 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 (RISC) processors.

[0048] The controller 250 may also include a memory device 254 (e.g., a memory) that may store information such as instructions, control software, look up tables, configuration data, etc. The memory device 254 may include a volatile memory, such as random access memory (RAM), and / or a nonvolatile memory, such as read-only memory (ROM). The memory device 254 may store a variety of information and may be used for various purposes. For example, the memory device 254 may store processor-executable instructions including firmware or software for the processing circuitry 252 to execute, 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 may store machine-readable instructions for the processing circuitry 252 to execute. The memory device 254 may include ROM, flash memory, a hard drive, or any other suitable optical, magnetic, or solid-state storage medium, or a combination thereof. The memory device 254 may store data, instructions, and any other suitable data. It should be appreciated that the memory device 254 may store processor-executable instructions (e.g., for execution via the processing circuitry 252) to enable operation of any of the components described herein and to enable any of the functionalities and / or operations described herein.

[0049] The controller 250 may be configured to control operation of components of the vapor compression system 14 and / or the bearing system 100 (e.g., fluid supply system 130) based on detected operating parameters of the vapor compression system 14 and / or the bearing system 100. To this end, the vapor compression system 14 includes one or more sensors 256 configured to detect operating parameters associated with or indicative of operating conditions of the vapor compression system 14 and the bearing system 100. For example, one or more of the sensors 256 may be disposed along the lubricant circuit 204 and may be configured to detect operating parameters of the working fluid directed through the lubricant circuit 204, such as temperature, pressure, flow rate, and so forth. In some embodiments, one or more sensors 256 may be configured to detect an operating parameter associated with the motor 50, such as a rotational speed of the shaft 104, a torque on the shaft 104, a temperature of the motor 50, and so forth. One or more sensors 256 may be configured to detect an operating parameter of the bearing assemblies 150, such as a detection of whether one or more bearing assemblies 150 is in contact (e.g., physical contact) with the shaft 104, as described further below.

[0050] In some embodiments, one of the sensors 256 may be configured to detect an operating parameter associated with the pressure accumulator 208, such as a pressure of working fluid within the fluid chamber 216 and / or a pressure of gas within the biasing chamber 214. Additionally or alternatively, one or more of the sensors 256 may be configured to detect a liquid level of working fluid within the condenser 34, which may be referenced before and / or during startup of the bearing system 100 and / or vapor compression system 14. In some embodiments, one or more of the sensors 256 may be configured to detect an operating parameter of the pump 206, such as noise emitted by the pump 206, vibration of the pump 206, working fluid liquid and / or vapor presence within the pump 206, a speed of the pump 206, and so forth. As will be appreciated, each sensor 256 included in the vapor compression system 14 may be communicatively coupled to the controller 250. Thus, the controller 250 may receive data and / or feedback from the sensors 256 and may control operation of the vapor compression system 14 and / or the bearing system 100 based on the feedback and / or data.

[0051] The controller 250 may control the subcooling of the working fluid in the lubricant circuit 204 by controlling the flow of the cooling fluid 224 through the heat exchanger 222. For example, the controller 250 may cause the modulating valve 230 to modulate the flow rate of the cooling fluid 224 based on one or more operating parameters of the vapor compression system 14 in order to subcool the working fluid to a desired temperature. To this end, the controller 250 may receive feedback from the sensors 256 and control the modulating valve 230 based on the feedback. For example, the controller 250 may determine or receive data (e.g., sensor data) indicative of the operating parameters, which may include temperature, hydrostatic pressure, vapor pressure, mass / volumetric flow rate, heat transfer, phase, and / or bubbles of the working fluid and / or cooling fluid 224 at relevant locations of the vapor compression system 14 (e.g., in the lubricant circuit 204, in the pump 206, upstream of the pump 206, downstream of the pump 206, in the bearing assemblies 150, in the liquid line portion 202, in the cooling fluid circuit 228, in the heat exchanger 222). The operating parameters may also include nominal or measured parameters of the compressor 32, the evaporator 38, the condenser 34, and any other components of the vapor compression system 14. Based on these operating parameters, the controller 250 may control the position of the modulating valve 230 to cool the working fluid. That is, the controller 250 may receive feedback from the sensors 256 and control the modulating valve 230 based on the feedback.

[0052] Additionally, the operating parameters may include a power or speed of the pump 206. As conditions of the vapor compression system 14 change, the controller 250 may control the pump speed to pressurize the working fluid accordingly. For example, the pump 206 may operate at a first pump speed in a startup mode of the vapor compression system 14 and a second pump speed in a running mode. The pump 206 may be controlled based on feedback from the sensors 256 and / or any of the operating parameters discussed above. Additionally, the modulating valve 230 may be controlled based on the pump speed. For example, a tendency of the working fluid to cavitate or flash may correlate with the pump speed. Indeed, the pump speed may affect the vapor pressure of the working fluid, such that greater pump speeds may promote increased cavitation. As such, a greater degree of subcooling may be needed to prevent or reduce cavitation. Accordingly, the modulating valve 230 may be controlled based on the speed of the pump 206. In particular, the pump speed may be positively correlated to the flow rate of the cooling fluid 224 and inversely correlated to the temperature of the working fluid. In some embodiments, the controller 250 may coordinate control of the pump 206 and the modulating valve 230 to avoid cavitation of the working fluid. For example, the controller 250 may limit the pump speed based on the position of the modulating valve 230.

[0053] The controller 250 may determine the appropriate pump speed and or flow rate of the cooling fluid 224 based on a relationship between the pump speed and a corresponding temperature (e.g., threshold temperature) at which the working fluid would or may cavitate at the pump speed. That is, a suitable temperature of the working fluid may be a function of the pump speed, and the controller 250 may be configured to control the temperature of the working fluid based on the relationship. In some embodiments, the relationship may be determined empirically based on observable indicators of cavitation or flashing. For example, cavitation may produce an identifiable sound or vibration in the pump that may be heard by an operator or sensed using one of the sensors 256. During a testing phase, an operator may operate the pump 206 to pump the working fluid at various pump speeds and temperatures while listening for sounds of cavitation. By recording the pump speeds and temperatures at which cavitation is observed, a function or model of the relationship between threshold temperatures and pump speed may be determined. For example, the model may be a table listing a range of pump speeds associated with respective threshold temperatures. The table may be stored in the memory 254 of the controller 250, and the controller 250 may reference the table to determine the threshold temperature associated with a current pump speed and adjust the modulating valve 230 accordingly.

[0054] In other embodiments, the vapor compression system 14 may include a cavitation sensor 258 configured to detect cavitation in the pump 206. The cavitation sensor 258 may detect cavitation based on a detected sound or intensity of vibrations at the pump 206. For example, the cavitation sensor 258 may be a piezoelectric sensor configured to transmit a signal to the controller 250 in response to detecting vibrations indicative of cavitation. In this way, the controller 250 may use the cavitation sensor 258 data as feedback for controlling the flow rate of the cooling fluid 224 (e.g., a position of the modulating valve 230). For example, the controller 250 may determine, based on cavitation levels determined by the cavitation sensor 258, that the working fluid is above the threshold temperature and should be cooled further. Then, the controller 250 may adjust the modulating valve 230 to increase the flow rate of the cooling fluid 224, thereby increasing heat transfer from the working fluid to further cool the working fluid below the threshold temperature.

[0055] In addition to reducing and / or avoiding cavitation of the working fluid within the pump 206, subcooling the working fluid as described herein may enable sustained flow of liquid working fluid in the event of a loss of pressure in the lubricant circuit 204. For example, operation of the pump 206 may be interrupted (e.g., due to a loss of electrical power), or the fluid conduit 205 may experience a blockage or leakage. In some cases, the vapor compressions system 14 may perform a coast down operation to bring the shaft 104 to a controlled stop. When normal operation of the vapor compression system 14 is interrupted, the pressure accumulator 208 may temporarily supply pressurized working fluid to the bearing assemblies 150. However, the pressure provided by the pressure accumulator 208 may be insufficient to maintain the working fluid in a liquid state. For example, the pressure of the pressure accumulator 208 may decrease over time as the working fluid is discharged, causing the working fluid to vaporize (e.g., transition to a two-phase or vapor state) if the working fluid is above a threshold temperature. Under such circumstances, the subcooling of the working fluid provided by the heat exchanger 222 may enable the working fluid to remain in a liquid state during pressure drops. In this way, operation of the bearings may be at least temporarily sustained (e.g., in a coast down operation) in the event of an interruption of normal operation (e.g., pressure drop) of the vapor compression system 14.

[0056] FIG. 7 is a schematic of an embodiment of the vapor compression system 14, illustrating supply of the cooling fluid 224 by the evaporator 38 and directed through the heat exchanger 222 via the cooling fluid circuit 228. The cooling fluid 224 may be a portion of conditioning fluid, such as water, that transfers heat to the working fluid within the evaporator 38. Then, the cooling fluid 224, after being cooled by the evaporator 38, may be discharged from an outlet of the evaporator 38 and be directed to flow through the heat exchanger 222, whereupon the cooling fluid 224 may absorb heat from the working fluid in the lubricant circuit 204. The cooling fluid 224, heated via the heat exchanger 222, may flow from the heat exchanger 222 back to the evaporator 38 to be cooled again. As discussed above, the cooling fluid circuit 228 may include the modulating valve 230 configured to modulate the flow of the cooling fluid 224 through the heat exchanger 222, thereby controlling a degree to which the working fluid is subcooled.

[0057] FIG. 8 is a schematic of an embodiment of the vapor compression system 14, illustrating the cooling fluid 224 as a portion of conditioning fluid 260 (e.g., water) routed to the load 62. As discussed above with respect to FIG. 3, the working fluid may absorb heat from (e.g., cool) the conditioning fluid 260 that is subsequently used to cool the load 62 (e.g., the building 12 of FIG. 1). For example, the conditioning fluid 260 may be cooled by the working fluid in the evaporator 38, and then may be utilized in the building 12 of FIG. 1 to condition an air flow provided to condition a space in the building 12. The conditioning fluid 260 may flow from the evaporator 38 to the load 62 via the supply line 60S. Additionally, a portion of the conditioning fluid 260 may flow (e.g., from the evaporator 38 or from the supply line 60S) to the heat exchanger 222 via the cooling fluid circuit 228 to cool the working fluid in the lubricant circuit 204. Subsequently, the cooling fluid 224, heated by the working fluid via the heat exchanger 222, may flow from the heat exchanger 222 to the evaporator 38. In some embodiments, a return flow of the cooling fluid 224 may join a return flow of the conditioning fluid 260 from the load 62 via the return line 60R.

[0058] FIG. 9 is a schematic of an embodiment of the vapor compression system 14, illustrating the cooling fluid 224 as a portion of the working fluid drawn from the condenser 34. Of the working fluid exiting the condenser 34, a first portion 262 (e.g., first flow) may flow through the lubricating circuit 204 toward the bearings, and a second portion 264 (e.g., second flow) may flow through the cooling fluid circuit 228 as the cooling fluid 224. The cooling fluid 224 (e.g., the second portion 264) may flow through an expansion device 266 (e.g., additional expansion device, expansion valve, thermal expansion valve [TXV]) configured to control the flow rate of the cooling fluid 224 into the heat exchanger 222. In particular, the expansion device 266 may restrict the flow of the cooling fluid 224 and reduce the pressure and / or temperature of the cooling fluid 224 downstream of the expansion device 266. As a result, the cooling fluid 224 may vaporize (e.g., flash) as it enters the heat exchanger 222. As a sensible heat of the cooling fluid 224 is converted to latent heat due to vaporization of the cooling fluid 224, the working fluid in the lubricant circuit 204 (e.g., first portion 262) may transfer heat to the cooling fluid 224 (e.g., second portion 264). In this way, the second portion 264 of the working fluid may subcool the first portion 262 of the working fluid via the heat exchanger 222. The first portion 262 of the working fluid, subcooled by the cooling fluid 224, may be pumped by the pump 206 toward the bearings of the compressor 32. The cooling fluid 224, heated by the first portion 262, may flow back into the working fluid circuit 200 to be condensed back into a liquid working fluid. For example, the cooling fluid 224 may exit the heat exchanger 222 and join a flow of the working fluid into an inlet of the compressor 32. In this way, the cooling fluid circuit may direct the second portion 264 of the working fluid from the heat exchanger 222 to the inlet (e.g., suction inlet 112) of the compressor 32.

[0059] While only certain features and embodiments have been illustrated and described, many modifications and changes may occur to those skilled in the art, such as variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, such as temperatures and pressures, mounting arrangements, use of materials, colors, orientations, and so forth, without materially 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 re-sequenced according to alternative embodiments. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the disclosure.

[0060] Furthermore, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not have been described, such as those unrelated to the presently contemplated best mode, or those unrelated to enablement. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, without undue experimentation.

[0061] The techniques presented and claimed herein are referenced and applied to material objects and concrete examples of a practical nature that demonstrably improve the present technical field and, as such, are not abstract, intangible or purely theoretical. Further, if any claims appended to the end of this specification contain one or more elements designated as “means for [perform]ing [a function] . . . ” or “step for [perform]ing [a function] . . . ”, it is intended that such elements are to be interpreted under 35 U.S.C. 112(f). However, for any claims containing elements designated in any other manner, it is intended that such elements are not to be interpreted under 35 U.S.C. 112(f).

Examples

Embodiment Construction

[0018]One or more specific embodiments will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated 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 developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

[0019]When introducing elements of various embodiments of the present disclosure, the articles “a,”“an,” and “the” are intended to mean that there are one or more of the elements....

Claims

1. A heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system, comprising:a working fluid circuit comprising an evaporator, a condenser, and a compressor; anda fluid supply system comprising a lubricant circuit configured to direct a flow of working fluid from the working fluid circuit to a bearing of the compressor, wherein the lubricant circuit comprises a heat exchanger configured to place the flow of working fluid in a heat exchange relationship with a cooling fluid.

2. The HVAC&R system of claim 1, wherein the heat exchanger is a brazed plate heat exchanger.

3. The HVAC&R system of claim 1, wherein the fluid supply system comprises:a cooling fluid circuit configured to direct the cooling fluid to the heat exchanger;a valve disposed along the cooling fluid circuit and configured to control a flow rate of the cooling fluid; anda controller configured to adjust the valve based on one or more operating parameters of the fluid supply system.

4. The HVAC&R system of claim 3, wherein the one or more operating parameters comprise a speed of a pump disposed along the lubricant circuit, a vibration intensity of the pump, a temperature of the flow of working fluid, a flow rate of the flow of working fluid along the lubricant circuit, or a combination thereof.

5. The HVAC&R system of claim 1, wherein the heat exchanger is configured to place the flow of working fluid and the cooling fluid in a counterflow heat transfer arrangement.

6. The HVAC&R system of claim 1, wherein the cooling fluid comprises a conditioning fluid cooled by the evaporator.

7. The HVAC&R system of claim 1, wherein the lubricant circuit is configured to direct the flow of working fluid from the condenser to the heat exchanger.

8. The HVAC&R system of claim 1, wherein the flow of working fluid is a first flow of working fluid, the fluid supply system comprises a cooling fluid circuit configured to direct the cooling fluid to the heat exchanger, and the cooling fluid circuit is configured to direct a second flow of working fluid from the condenser to the heat exchanger as the cooling fluid.

9. The HVAC&R system of claim 8, wherein the fluid supply system comprises an expansion valve disposed along the cooling fluid circuit between the condenser and the heat exchanger.

10. A heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system, comprising:a working fluid circuit comprising a condenser, an evaporator, and a compressor, wherein the working fluid circuit is configured to circulate a working fluid therethrough;a lubricant circuit configured to direct a portion of the working fluid from the working fluid circuit to a bearing of the compressor;a heat exchanger disposed along the lubricant circuit between the working fluid circuit and the bearing, relative to a flow direction of the portion of the working fluid along the lubricant circuit;a cooling fluid circuit configured to circulate a cooling fluid through the heat exchanger, wherein the heat exchanger is configured to facilitate heat transfer from the portion of the working fluid to the cooling fluid; anda pump disposed along the lubricant circuit and configured to direct the portion of working fluid from the heat exchanger to the bearing.

11. The HVAC&R system of claim 10, comprising:a valve disposed along the cooling fluid circuit, wherein the valve is configured to control a flow rate of the cooling fluid; anda controller configured to adjust the valve based on a speed of the pump.

12. The HVAC&R system of claim 10, wherein the lubricant circuit is configured to direct the portion of the working fluid from the condenser to the heat exchanger, and working fluid circuit is configured to direct a remaining portion of the working fluid from the condenser to the evaporator.

13. The HVAC&R system of claim 10, comprising:a cooling fluid return conduit configured to direct the cooling fluid from a load to the evaporator; anda cooling fluid supply conduit configured to direct the cooling fluid from the evaporator to the load,wherein the evaporator is configured to place the cooling fluid in a heat exchange relationship with the working fluid to cool the working fluid, the cooling fluid circuit is configured to direct the cooling fluid from the cooling fluid supply conduit to the heat exchanger, and the cooling fluid circuit is configured to direct the cooling fluid from the heat exchanger to the cooling fluid return conduit.

14. The HVAC&R system of claim 10, wherein the cooling fluid circuit is configured to direct an additional portion of the working fluid from the condenser to the heat exchanger as the cooling fluid.

15. The HVAC&R system of claim 14, wherein the cooling fluid circuit comprises an expansion device disposed downstream of the condenser and upstream of the heat exchanger relative to a flow direction of the additional portion of the working fluid along the cooling fluid circuit.

16. The HVAC&R system of claim 15, wherein the cooling fluid circuit is configured to direct the additional portion of the working fluid from the heat exchanger to a suction inlet of the compressor.

17. A heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system, comprising:a condenser disposed along a working fluid circuit;a compressor disposed along the working fluid circuit, wherein the compressor comprises a bearing; anda heat exchanger of a lubricant circuit, wherein the heat exchanger is configured to receive a flow of working fluid from the condenser and to place the flow of working fluid in a heat exchanger relationship with a cooling fluid, wherein the lubricant circuit is configured to direct the flow of working fluid from the heat exchanger to the bearing.

18. The HVAC&R system of claim 17, comprising a pump disposed along the working fluid circuit, wherein the pump is configured to direct the flow of working fluid from the heat exchanger to the bearing.

19. The HVAC&R system of claim 18, comprising:a valve configured to control a flow rate of the cooling fluid through the heat exchanger; anda controller configured to adjust the valve based on one or more operating parameters of the HVAC&R system.

20. The HVAC&R system of claim 19, wherein the one or more operating parameters comprise a speed of the pump, a detected intensity of vibration at the pump, or both.

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