Two-phase hybrid bearing with trip buffer tank

Abstract

The heating, ventilation, air conditioning, and refrigeration (HVAC&R) system includes a compressor (32), a motor (50) configured to drive the rotor of the compressor, and bearings configured to support the rotor load of the rotor. The HVAC&R system also includes a normal operating tank configured to supply a liquid or two-phase fluid to lubricate the bearings or parts thereof under normal operating conditions, and a buffer trip tank configured to supply a fluid in the form of vapor to lubricate multiple bearings or parts thereof under abnormal operating conditions.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the priority and benefit of U.S. Provisional Patent Application No. 63 / 469,752, filed on May 30, 2023, entitled "DIPHASIC HYBRID BEARINGS WITH TRIP BUFFER TANK", which is hereby incorporated by reference in its entirety for all purposes.

Background Art

[0002] This section is intended to introduce the reader to various aspects of the relevant art that may relate to the various aspects of the present disclosure described and / or claimed 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, these descriptions should be read from this perspective and should not be construed as an admission of prior art.

[0003] A chiller system, or vapor compression system, may utilize a working fluid (e.g., refrigerant, etc.) that changes phase between vapor, liquid, and mixtures thereof in response to being exposed to different temperatures and pressures within the 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 deliver the conditioning fluid to conditioning equipment provided by and / or the environment to be conditioned by the chiller system. For example, the chiller system may include a heat exchanger configured to receive the working fluid and the conditioning fluid and place the working fluid in a heat - exchange relationship with the conditioning fluid. The conditioning fluid may be directed from the heat exchanger to other equipment, such as an air handler, to condition other fluids, such as air within a building. The working fluid may be directed from the heat exchanger through other components of the chiller system, such as a compressor and / or condenser configured to process (e.g., pressurize, cool) the working fluid to enable the working fluid to provide further conditioning of the conditioning fluid.

[0004] Various bearings (e.g., thrust bearings, radial bearings) may be employed in a compressor to provide axial and / or radial support to the rotor load corresponding to the compressor rotor. In certain conventional embodiments, one or more of the bearings may be lubricated with oil, which may contribute to the cost and / or complexity of the system. Furthermore, in certain conventional embodiments, including those that do not employ oil-lubricated bearings, the compressor may suffer, among other possible adverse effects, reduced stiffness, reduced damping, reduced cross-stiffness capacity which induces a lower margin to transient loads, sudden load fluctuations (e.g., increases or decreases), vibration, increased likelihood of entering a surge condition (and / or reduced ability to respond to a surge condition), bearing stress, or any combination thereof. Therefore, it is now recognized that improved systems and methods are desired. [Overview of the Initiative]

[0005] An overview of certain embodiments disclosed herein is provided below. These embodiments are presented solely to provide the reader with a brief overview of these particular embodiments, and it should be understood that they are not intended to limit the scope of this disclosure. In fact, this disclosure may encompass a variety of embodiments not described below.

[0006] In one embodiment, a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system includes a compressor, a motor configured to drive the rotor of the compressor, and bearings configured to support the rotor load of the rotor. The HVAC&R system also includes a normal operating tank configured to supply a liquid or two-phase fluid to lubricate the bearings or a portion thereof under normal operating conditions, and a buffer trip tank configured to supply a fluid in the form of vapor to lubricate a plurality of bearings or a portion thereof under abnormal operating conditions.

[0007] In another embodiment, a bearing assembly for a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system includes a bearing configured to support the rotor load of a compressor rotor. The bearing assembly also includes a normal operating tank configured to supply a liquid or two-phase fluid to lubricate the bearing or a portion thereof under normal operating conditions. The bearing assembly also includes a buffer-trip tank configured to supply a fluid in vapor form (e.g., substantially pure vapor form) to lubricate the bearing or a portion thereof under abnormal (e.g., emergency or trip) operating conditions.

[0008] In another embodiment, a method for operating a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system includes driving the rotation of a compressor rotor via a motor. The method also includes supporting the rotor load of the rotor via bearings. The method also includes lubricating the bearings or a portion thereof with a liquid or two-phase fluid maintained by a normal operating tank during normal operating conditions. The method also includes lubricating the bearings or a portion thereof with a vapor fluid (e.g., substantially pure vapor) maintained by a buffer-trip tank during abnormal (e.g., emergency or trip) operating conditions.

[0009] Various aspects of this disclosure can be better understood by reading the following detailed description and referring to the drawings. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view of a building utilizing one embodiment of a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system in a commercial environment, according to one aspect of the present disclosure. [Figure 2] This is a perspective view of one embodiment of a vapor compression system according to one aspect of the present disclosure. [Figure 3] This is a schematic diagram of one embodiment of the vapor compression system shown in Figure 2, according to one aspect of the present disclosure. [Figure 4] This is a schematic diagram of one embodiment of the vapor compression system shown in Figure 2, according to one aspect of the present disclosure. [Figure 5] This is a schematic diagram of a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system employing a compressor having at least one two-phase hybrid (e.g., aerodynamic / hydrostatic) bearing, according to one aspect of the present disclosure. [Figure 6] This is a process flow diagram illustrating a method for operating the centrifugal compressor shown in Figure 5 according to one aspect of the present disclosure. [Modes for carrying out the invention]

[0011] One or more specific embodiments are described below. Not all features of actual implementations are described herein in order to provide a concise description of these embodiments. It should be recognized that in developing any such actual implementation, as in any engineering or design project, many implementation-specific decisions, which may differ from implementation to implementation, must be made in order to achieve developer-specific goals, such as compliance with system-related and industry-related constraints. Furthermore, it should be recognized that while such development efforts may be complex and time-consuming, they are still considered normal business of design, fabrication, and manufacturing for those skilled in the art who are interested in this disclosure.

[0012] When introducing elements of the various embodiments of this disclosure, the articles “a,” “an,” and “the” are intended to indicate that one or more of the elements exist. The terms “comprising,” “including,” and “having” are intended to be comprehensive and mean that additional elements other than those enumerated may exist. Additionally, it should be noted that references to “one embodiment” or “an embodiment” in this disclosure are not intended to be construed as excluding the existence of additional embodiments that similarly incorporate the enumerated features.

[0013] Where used herein, terms such as “approximately,” “generally,” and “substantially” are intended to convey, as a person skilled in the art would understand, that the described characteristic value may fall within a relatively small range of characteristic values. For example, when a characteristic value is described as “approximately” equal to (or, for example, “substantially similar to”) a given value, this is intended to convey that the characteristic value may be within ±5%, ±4%, ±3%, ±2%, ±1% of the given value, or even closer to it. Similarly, when a given feature is described as “substantially parallel” to another feature, or “generally perpendicular” to another feature, this is intended to convey that the given feature may be within ±5%, ±4%, ±3%, ±2%, ±1%, or even closer to having the described property, such as being parallel or perpendicular to another feature. Mathematical terms such as “parallel” and “perpendicular” should not be interpreted strictly in their strict mathematical sense, but rather should be interpreted as a person skilled in the art would interpret such terms. For example, a person skilled in the art will understand that two lines that are substantially parallel to each other are parallel to a substantial degree, but may deviate slightly from being perfectly parallel.

[0014] Embodiments of the present disclosure relate to HVAC&R systems, such as chiller systems, having a vapor compression system having at least one two-phase hybrid (e.g., aerodynamic / hydrostatic) bearing supporting the rotor load of the compressor of a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system. The vapor compression system may include a compressor configured to pressurize a working fluid (e.g., a refrigerant) and discharge the pressurized working fluid into a condenser configured to condense and cool the working fluid. The condenser may discharge the working fluid into an expansion valve configured to reduce the pressure of the working fluid, thereby further cooling the working fluid. The working fluid may be directed from the expansion valve to an evaporator, which may be configured to cool the regulating fluid and heat the working fluid by putting the working fluid (e.g., cooled working fluid) into a heat exchange relationship with a regulating fluid. The evaporator may then discharge the working fluid into a compressor. The regulating fluid (e.g., water, air, etc.) may be employed to regulate the load (e.g., cooling a residential or commercial space).

[0015] According to this disclosure, a compressor may include at least one two-phase hybrid (e.g., aerodynamic / hydrostatic) bearing, such as a plurality of two-phase hybrid bearings, that support a rotor load corresponding to the rotor of the compressor of an HVAC&R system. Unlike certain conventional embodiments that employ oil-lubricated bearings, embodiments of this disclosure may lubricate the two-phase hybrid bearing via a first reservoir (e.g., a primary or normal reservoir or tank, accumulator, etc.) pressurized by a liquid pump, or via a second reservoir (e.g., an emergency or buffer reservoir or trip tank, accumulator, etc.). For example, the first reservoir may be employed under normal operating conditions, and the second reservoir may be employed under abnormal (e.g., emergency or trip) operating conditions. The first reservoir may provide a liquid or a vapor-liquid mixture to lubricate the two-phase hybrid bearing, while the second reservoir may be configured to provide vapor (e.g., substantially pure vapor) to lubricate the two-phase hybrid bearing. The steam may include, for example, substantially pure steam (e.g., 95% steam, 99% steam, or more). In certain embodiments, the second reservoir may be maintained at a higher pressure than the first reservoir.

[0016] In the bearing assembly according to this embodiment (referred to in certain instances of this disclosure as a lubrication assembly and / or bearing lubrication assembly), various features (e.g., subcoolers, liquid pumps, evaporators, filters, check valves, safety relief valves, rapid-acting solenoid valves, and electric heaters) and other possible components may be employed. Among other technical advantages, the embodiments of this disclosure may enable, compared to conventional embodiments, improved stiffness, improved damping, improved cross-stiffness capacity which induces improved margin against transient loads, reduced sudden load fluctuations (e.g., increases or decreases), reduced vibration, reduced likelihood of entering a surge condition (and / or improved response to a surge condition), reduced bearing stress, or any combination thereof.

[0017] Referring here to the drawings, Figure 1 is a perspective view of one embodiment of the environment of a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system 10 in a building 12 for a typical commercial environment. The HVAC&R system 10 may include a vapor compression system 14 (e.g., a chiller) that supplies a cooled liquid which can be used to cool the building 12. The HVAC&R system 10 may also include a boiler 16 for supplying a warm liquid for heating the building 12, and an air distribution system for circulating air through the building 12. The air distribution system may 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 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 a heated liquid from the boiler 16 or a cooled liquid from the vapor compression system 14, depending on the operating mode of the HVAC&R system 10. While the HVAC&R system 10 is shown with separate air handlers on each floor of the building 12, in other embodiments, the HVAC&R system 10 may include air handlers 22 and / or other components that can be shared between floors.

[0018] Figures 2 and 3 show embodiments of a vapor compression system 14 that can be used within an HVAC&R system 10. The vapor compression system 14 may circulate a refrigerant through a circuit starting with a compressor 32. The circuit may also include a condenser 34, an expansion valve(s) or expansion device 36(s), and a liquid chiller or evaporator 38. The vapor compression system 14 may further include a control panel 40 having an analog-to-digital (A / D) converter 42, a microprocessor 44, non-volatile memory 46, and / or an interface board 48.

[0019] Some examples of fluids that can be used as refrigerants in the vapor compression system 14 are hydrofluorocarbon (HFC) refrigerants, such as R-410A, R-407, R-134a, R-1234ze, R1233zd, R513A, hydrofluoroolefins (HFO), ammonia (NH3), R-717, carbon dioxide (CO2), R-744, or "natural" refrigerants such as hydrocarbon refrigerants, water vapor, or any other suitable refrigerant. In some embodiments, the vapor compression system 14 may be configured to efficiently utilize refrigerants having a standard boiling point of about 19 degrees Celsius (66 degrees Fahrenheit) at atmospheric pressure, also referred to as low-pressure refrigerants, compared to medium-pressure refrigerants such as R-134a. As used herein, "standard boiling point" may refer to the boiling temperature measured at atmospheric pressure.

[0020] In some embodiments, the vapor compression system 14 may use one or more of the following: a variable speed drive (VSD) 52, a motor 50, a compressor 32, a condenser 34, an expansion valve or expansion device 36, and / or an evaporator 38. The motor 50 may drive the compressor 32 and may be powered by the variable speed drive (VSD) 52. The VSD 52 receives AC power having a specific fixed line voltage and fixed line frequency from an alternating current (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 motor that can be powered by the VSD or directly from an AC or DC power source, such as a switched reluctance motor, an induction motor, an electronically rectified permanent magnet motor, or another suitable motor.

[0021] The compressor 32 compresses the refrigerant vapor and delivers the vapor to the condenser 34 through the discharge passage. In some embodiments, the compressor 32 can be a centrifugal compressor. The refrigerant vapor delivered to the condenser 34 by the compressor 32 can transfer heat to a cooling fluid (e.g., water or air) within the condenser 34. The refrigerant vapor can condense into a refrigerant liquid within the condenser 34 due to heat transfer with the cooling fluid. The liquid refrigerant from the condenser 34 can 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 that supplies the cooling fluid to the condenser 34.

[0022] The liquid refrigerant delivered to the evaporator 38 can absorb heat from another cooling fluid, which may or may not be the same cooling fluid used in the condenser 34. The liquid refrigerant within the evaporator 38 can undergo a phase change from the liquid refrigerant to the refrigerant vapor. As shown in the illustrated embodiment of FIG. 3, the evaporator 38 can include a tube bundle 58 having a supply line 60S and a return line 60R connected to a cooling load 62. The cooling fluid (e.g., water, ethylene glycol, calcium chloride brine, sodium chloride brine, or any other suitable fluid) of the evaporator 38 enters the evaporator 38 via the return line 60R and exits the evaporator 38 via the supply line 60S. The evaporator 38 can reduce the temperature of the cooling fluid within the tube bundle 58 through heat transfer with the refrigerant. The tube bundle 58 within the evaporator 38 can include a plurality of tubes and / or a plurality of tube bundles. In either case, the vapor refrigerant exits the evaporator 38 and returns to the compressor 32 via the suction line to complete the cycle.

[0023] FIG. 4 is a schematic of a vapor compression system 14 having an intermediate circuit 64 incorporated between a condenser 34 and an expansion device 36. The intermediate circuit 64 may have an inlet line 68 that is directly fluid-connected to the condenser 34. In other embodiments, the inlet line 68 may be indirectly fluid-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, economizer, etc.). 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 reduce (e.g., expand) the pressure of the liquid refrigerant received from the condenser 34. During the expansion process, a portion of the liquid may vaporize, and thus, the intermediate vessel 70 may be used to separate the vapor from the liquid received from the first expansion device 66.

[0024] Additionally, the intermediate vessel 70 may provide further expansion of the liquid refrigerant due to the pressure drop it experiences when the liquid refrigerant enters the intermediate vessel 70 (e.g., due to the sudden increase in volume it experiences when entering the intermediate vessel 70). The vapor within the intermediate vessel 70 may be drawn in by the compressor 32 through the suction line 74 of the compressor 32. In other embodiments, the vapor within the intermediate vessel may be drawn into an intermediate stage of the compressor 32 (e.g., not the suction stage). The liquid that accumulates in the intermediate vessel 70 may have an enthalpy lower than that of the liquid refrigerant exiting the condenser 34 for expansion in the expansion device 66 and / or within the intermediate vessel 70. Then, the liquid from the intermediate vessel 70 may flow through line 72 and through a second expansion device 36 to the evaporator 38.

[0025] It should be recognized that any of the features described herein can be incorporated into the vapor compression system 14 or any other suitable HVAC&R system. For example, the technology can be incorporated into any HVAC&R system having an economizer such as an intermediate vessel 70 and a compressor such as a compressor 32. The following discussion will describe the technology incorporated into an embodiment of the compressor 32 configured as a single-stage compressor. However, it should be noted that the systems and methods described herein can be incorporated into other embodiments of the compressor 32 and the HVAC&R system 10.

[0026] This disclosure relates to HVAC&R systems that utilize two-phase hybrid (e.g., aerodynamic / hydrostatic) bearings to support rotor loads corresponding to compressors (e.g., centrifugal compressors), such as the compressor(s) 32 described above with respect to Figures 1-4. Unlike certain conventional embodiments employing oil-lubricated bearings, embodiments of this disclosure may lubricate the two-phase hybrid bearings of the compressor 32 via a first reservoir (e.g., primary or normal reservoir, accumulator, etc.) pressurized by a liquid pump in certain operating conditions (e.g., normal operating conditions), and via a second reservoir (e.g., emergency or buffer trip tank, accumulator, etc.) in certain other operating conditions (e.g., abnormal operating conditions such as emergency or trip conditions).

[0027] A first reservoir may provide a liquid (or a vapor-liquid mixture) to lubricate the two-phase hybrid bearing, while a second reservoir may be configured to provide vapor (e.g., substantially pure vapor) to lubricate the two-phase hybrid bearing. In certain embodiments, the second reservoir may be maintained at a higher pressure than the first reservoir. Various features (e.g., subcoolers, liquid pumps, evaporators, filters, check valves, safety relief valves, rapid-acting solenoid valves, and electric heaters, among other possible components) may be employed in the lubrication assembly according to this disclosure. Among other technical advantages, embodiments of this disclosure may enable improved stiffness, improved damping, improved cross-stiffness capacity leading to improved margins against transient loads, reduced sudden load fluctuations, reduced vibration, reduced likelihood of surge conditions, and / or reduced bearing stress compared to conventional embodiments. These and other features are described in detail below with reference to Figures 5 and 6.

[0028] With the above in mind, Figure 5 is a schematic diagram of a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system 100 that employs a compressor 102 (e.g., a centrifugal compressor) having a two-phase hybrid (e.g., aerodynamic / hydrostatic) bearing 104 (e.g., two or more two-phase hybrid bearings). The compressor 102 may be the same as or similar to the compressor 32 described above with respect to certain particular embodiments illustrated in Figures 1 to 4. The system 100 generally includes a vapor compression circuit 105 employing the compressor 102, an evaporator 106, an expansion valve 108, and a condenser 110. The compressor 102, evaporator 106, expansion valve 108, and condenser 110 may be employed for the same or similar reasons (and / or in the same or similar manner) described above with respect to certain particular embodiments illustrated in Figures 1 to 4.

[0029] Generally, a motor 112 corresponding to a compressor 102 may rotationally drive the rotor 114 of the compressor 102 (e.g., including a shaft), which in turn compresses the refrigerant 116 in the vapor compression circuit 105 before it is delivered to the condenser 110 via a fluid transmission line 117 (e.g., a discharge line, conduit, etc.). It should be understood that various examples or embodiments of the fluid transmission line 117 may be configured to guide the refrigerant 116 around various parts of the system 100 (e.g., around the vapor compression circuit 105, around the lubrication assembly 118, etc.). A two-phase hybrid bearing 104 may be configured to support the rotor load corresponding to the compressor 102. A lubrication assembly 118 of the HVAC&R system 100 (referred to in certain instances of this disclosure as a bearing assembly and / or bearing lubrication assembly) may be employed to provide a fluid (e.g., a portion of the refrigerant 116) configured to lubricate the two-phase hybrid bearing 104. As shown, the lubrication assembly 112 may include, among other features described in detail below, a subcooler 120, a liquid pump 122, a preheater 124, a partial evaporator 126, a first check valve 128, a filter 130, a first reservoir 132 (e.g., a primary reservoir, a first pressure accumulator, a primary pressure accumulator, a primary tank, etc.), and a second check valve 133. The two-phase hybrid bearing 104 may also be part of the lubrication assembly 118 (e.g., a bearing assembly, a bearing lubrication assembly, etc.).

[0030] Generally, a subcooler 120 (which may be optional and may be provided within the lubrication assembly 118, separate from another subcooler included in the vapor compression circuit 105) may be configured to subcool a portion of the refrigerant 116; a liquid pump 122 may be configured to move a portion of the refrigerant 116 through the lubrication assembly 118; a preheater 124 may be configured to preheat a portion of the refrigerant 116; an evaporator 126 (e.g., a partial evaporator / flash evaporator) may be configured to evaporate or flash evaporate a portion of the refrigerant 116 (e.g., to generate vapor); and a check valve 128 may be configured to prevent a portion of the refrigerant 116 in the lubrication assembly 118 from flowing back towards the evaporator 126 (e.g., a partial evaporator / flash evaporator).

[0031] In the normal operating state of the compressor 102, a fluid in liquid or two-phase form 134a (e.g., a portion of the refrigerant 116) may be supplied to the two-phase hybrid bearing 104 via the lubrication assembly 118, corresponding to a first reservoir 132 (e.g., a primary tank). The first reservoir 132 (e.g., a primary tank, a normal operating tank, a primary reservoir, a first pressure accumulator, etc.) may include a membrane and / or hydraulic accumulator employing a pressurized fluid, such as nitrogen gas (N2), to pressurize the fluid supplied to the bearing 104 in liquid or two-phase form 134a (e.g., a portion of the refrigerant 116). For example, the first reservoir 132 may include a first volume section and a second volume section separated by a membrane (e.g., a bell rose or diaphragm), where N2 (or some other vapor-phase pressurized fluid such as air) is contained in the first volume section and maintained at a substantially constant pressure or within a relatively small pressure range, and a fluid configured to be supplied to the bearing 104 (e.g., a portion of the refrigerant 116) is contained in the second volume section. In this way, lubrication is not affected by fluctuations in the lubrication fluid pressure. A filter 130 may be employed upstream of the bearing 104 to filter out any particles before the liquid or two-phase fluid 134a (e.g., a portion of the refrigerant 116) is delivered to the bearing 104.

[0032] In abnormal operating conditions (e.g., such as an emergency and / or tripping condition), other components of the lubrication assembly 118 may be employed to provide the two-phase hybrid bearing 104 with a fluid a (e.g., a portion of the refrigerant 116) in vapor form 134b (e.g., substantially pure vapor form, e.g., 95% vapor form or 99% vapor form). For example, as shown, the lubrication assembly 118 may include a second reservoir 136 (e.g., a secondary tank, buffer trip tank, secondary reservoir, second pressure accumulator, etc.), an electric heater 138 corresponding to the second reservoir 136, a safety relief valve 140, a rapid-acting solenoid valve 142, a third check valve 144, and a fourth check valve 146. In general, some or all of these features may be employed to provide the two-phase hybrid bearing 104 with a fluid in pure vapor form 134b (e.g., substantially pure vapor form) during abnormal operating conditions (e.g., emergency or trip conditions). For example, the second reservoir 136 may include a membrane and / or hydraulic accumulator that employs a pressurized fluid, such as nitrogen gas (N2), to pressurize the fluid (e.g., a portion of the refrigerant 116) supplied to the bearing 104 in pure vapor form 134b (e.g., substantially pure vapor form) during abnormal conditions (e.g., emergency or trip conditions).

[0033] In some embodiments, the first reservoir 136 may include a first volume section and a second volume section separated by a membrane (e.g., a bellows or diaphragm), where N2 (or some other vapor-phase pressurized fluid such as air) is contained in the first volume section and maintained at a substantially constant pressure or within a relatively small pressure range, and a fluid configured to be supplied to the bearing 104 (e.g., a portion of the refrigerant 116) is contained in the second volume section. In this way, lubrication is not affected by fluctuations in the lubrication fluid pressure. In some embodiments, the second reservoir 136 is maintained at a higher pressure than the first reservoir 132. An electric heater 138 may be employed to transfer heat to the second reservoir 136 and / or to pressurize the second reservoir 136.

[0034] Furthermore, the rapid-acting solenoid valve 142 may be configured to allow or block the flow of fluid in vapor form 134b (e.g., substantially pure vapor form) toward the bearing 104 of the compressor 102, depending on the operating mode. For example, in the normal operating mode, when the compressor 102 is operating normally, the rapid-acting solenoid valve 142 may be controlled to block the flow of fluid in vapor form 134b (e.g., substantially pure vapor form) toward the bearing 104 (e.g., while a liquid or two-phase fluid 134a is supplied to the bearing 104 via the first reservoir 132). In abnormal (e.g., emergency or trip) operating conditions, the rapid-acting solenoid valve 142 is controlled to allow the flow of fluid in vapor form 134b (e.g., substantially pure vapor form) toward the bearing 104.

[0035] In some embodiments, the rapid-acting solenoid valve 142 is controlled by a control assembly 150 having a memory circuit 152 (e.g., including one or more memories) that stores instructions, and a processing circuit 154 (e.g., including one or more processors) configured to execute instructions to perform various functions, such as controlling the rapid-acting solenoid valve 142. Such control may be at least in part based on sensor data received by the processing circuit 154 from a sensor 156. The sensor 156 may be configured to detect operating conditions indicating normal and / or abnormal (e.g., emergency / trip) conditions. For example, the sensor 156 (representing one or more sensors) may be a proximity sensor (e.g., an axial or radial proximity sensor) with a threshold set to an alarm or trip level. Additionally or alternatively, the sensor 156 may be configured to detect the pressure or temperature of the refrigerant 116. In some embodiments, multiple sensors are employed. Furthermore, in some embodiments, the switching between the first reservoir 132 and the second reservoir 136 may be mechanically tuned to one or more operating characteristics. Check valves 133, 144, and 146 may be employed for a variety of reasons, such as counteracting backflow of fluid in the corresponding lines, enabling emergency pressurization of bearing 104 (e.g., via the second reservoir 136), preventing the use of the first reservoir 132 for lubrication during abnormal (e.g., emergency / trip) conditions, and preventing the second reservoir 136 from being pressurized by the first reservoir 132.

[0036] Figure 6 is a process flow diagram illustrating one embodiment of a method 200 for operating the HVAC&R system 100 of Figure 5. In the embodiment illustrated, method 200 includes operating the compressor (block 202) by rotationally driving the rotor (e.g., shaft) of the compressor via a motor. Bearings (e.g., two-phase hybrid bearings) may be employed to support the rotor load corresponding to the compressor.

[0037] Method 200 also includes providing a liquid or two-phase fluid (e.g., a refrigerant) to a bearing (e.g., a two-phase hybrid bearing) to lubricate the bearing during the normal operating state of the compressor (block 204). For example, a first reservoir (e.g., a first tank or accumulator such as a first membrane pressurized by nitrogen gas [N2] or a hydraulic accumulator) may be employed to provide a portion of the liquid or two-phase fluid (e.g., a refrigerant) to the bearing during the normal operating state.

[0038] Method 200 also includes providing a fluid (e.g., a refrigerant) in vapor form (e.g., substantially pure vapor form) to a bearing (e.g., a two-phase hybrid bearing) to lubricate the bearing during an abnormal condition (e.g., emergency or trip) of the compressor (block 206). For example, a second reservoir (e.g., a second tank or emergency / trip tank or accumulator, such as a second membrane or hydraulic accumulator pressurized by nitrogen gas [N2]) may be employed to provide a portion of the fluid (e.g., a refrigerant) in vapor form (e.g., substantially pure vapor form) to the bearing during normal operating conditions. In some embodiments, a rapid-acting solenoid valve may be controlled to either allow the flow of the fluid in vapor form (e.g., substantially pure vapor form) to the bearing (e.g., during an emergency / trip condition) or to block the flow of the fluid in vapor form to the bearing (e.g., during normal operating conditions). Such control may, in certain embodiments, be performed by a control assembly (e.g., a controller, or including a controller) that receives sensor feedback in which a normal or emergency / trip state can be identified by the control assembly.

[0039] While only certain features and embodiments of this disclosure have been illustrated and described, those skilled in the art will be able to conceive of numerous modifications and changes, such as variations in the size, dimensions, structure, shape, and proportions of various elements, parameter values ​​including temperature and pressure, mounting arrangement, material use, color, orientation, etc., without substantially departing from the novel teachings and merits of the subject matter enumerated in the claims. Any order or sequence of process or method steps may be modified or rearranged according to alternative embodiments. It should be understood that the attached claims are intended to cover all such modifications and changes that fall within the true spirit of this disclosure. Furthermore, in order to provide a concise description of the exemplary embodiments, not all features of actual implementations may be described, including those irrelevant to the current best mode intended for carrying out this disclosure or irrelevant to enabling the claimed disclosure. It should be noted that, as with any engineering or design project, in the development of any such actual implementation, numerous implementation-specific decisions may be made. Such development efforts may be complex and time-consuming, but for those skilled in the art who are interested in this disclosure, they would still be part of the normal business of design, fabrication, and manufacturing, without excessive experimentation.

[0040] The technologies presented and claimed herein are not abstract, intangible, or purely theoretical, as they refer to and apply to specific objects and examples of a practical nature that clearly improve the art. Furthermore, if any of the claims attached to the end of this specification contain one or more elements designated as “means for carrying out the [function]” or “steps for carrying out the [function],” such elements are intended to be construed under Section 112(f) of the United States Patent Act. However, if any of the claims contain elements designated in any other form, such elements are not intended to be construed under Section 112(f) of the United States Patent Act.

Claims

1. A heating, ventilation, air conditioning, and refrigeration (HVAC&R) system, Compressor and, A motor configured to drive the rotor of the compressor, Multiple bearings configured to support the rotor load of the rotor, A normal operating tank configured to supply a liquid or two-phase fluid to lubricate the plurality of bearings or a portion thereof in a normal operating state, A buffer trip tank configured to supply the fluid in vapor form to lubricate the plurality of bearings or a portion thereof in an abnormal operating state, Equipped with an HVAC&R system.

2. The HVAC&R system according to claim 1, wherein at least one of the plurality of bearings is a two-phase hybrid bearing.

3. Proximity sensor and, The HVAC&R system according to claim 1, further comprising: a controller configured to receive sensor feedback from the proximity sensor and to control one or more components of the HVAC&R system to switch between the normal operation tank and the buffer trip tank in response to the sensor feedback.

4. The HVAC&R system according to claim 3, wherein one or more of the components comprises a rapid-acting solenoid valve.

5. The aforementioned normally operating tank is equipped with a first accumulator, The buffer trip tank comprises a second accumulator. The HVAC&R system according to claim 1.

6. The first accumulator comprises a first volume section and a second volume section separated by a membrane, wherein the first volume section is configured to receive a first vapor phase fluid maintained within a first pressure range, and the second volume section is configured to receive the fluid in liquid or two-phase form. The second accumulator comprises an additional first volume section and an additional second volume section separated by an additional membrane, wherein the additional first volume section is configured to receive a second vapor phase fluid maintained within a second pressure range, and the second volume section is configured to receive the fluid in vapor form. The HVAC&R system according to claim 5.

7. The first vapor phase fluid, the second vapor phase fluid, or both are nitrogen gas (N ２ The HVAC&R system according to claim 6, including ).

8. During the aforementioned abnormal operating state, the use of the buffer trip tank is enabled, and the use of the normal operation tank is disabled. To prevent the buffer trip tank from being pressurized by the normal operation tank, The HVAC&R system according to claim 1, comprising a plurality of check valves configured as follows.

9. A bearing assembly for heating, ventilation, air conditioning, and refrigeration (HVAC&R) systems, Multiple bearings configured to support the rotor load of the compressor rotor, A normal operating tank configured to supply a liquid or two-phase fluid to lubricate the plurality of bearings or a portion thereof in a normal operating state, A buffer trip tank configured to supply the fluid in vapor form to lubricate the plurality of bearings or a portion thereof in an abnormal operating state, A bearing assembly comprising:

10. The bearing assembly according to claim 9, wherein at least one of the plurality of bearings comprises a two-phase hybrid bearing.

11. Proximity sensor and, A controller configured to receive sensor feedback from the proximity sensor and to control switching between the normal operation tank and the buffer trip tank in response to the sensor feedback, The bearing assembly according to claim 9, comprising:

12. The bearing assembly according to claim 11, wherein the controller is configured to control the switching between the normal operation tank and the buffer trip tank in response to the sensor feedback by controlling a rapid-acting solenoid valve.

13. The conventional operating tank comprises a first accumulator having a first volume section and a second volume section separated by a membrane, wherein the first volume section is configured to receive a first vapor phase fluid maintained within a first pressure range, and the second volume section is configured to receive the fluid in liquid or two-phase form. The buffer trip tank comprises a second accumulator having an additional first volume section and an additional second volume section separated by an additional membrane, wherein the additional first volume section is configured to receive a second vapor phase fluid maintained within a second pressure range, and the second volume section is configured to receive the fluid in vapor form. The bearing assembly according to claim 9.

14. During the aforementioned abnormal operating state, the use of the buffer trip tank is enabled, and the use of the normal operation tank is disabled. To prevent the buffer trip tank from being pressurized by the normal operation tank, The bearing assembly according to claim 9, comprising a plurality of check valves configured as follows.

15. A method for operating a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system, Driving the rotation of the compressor rotor via a motor, Supporting the rotor load of the rotor via multiple bearings, During normal operation, the plurality of bearings or a portion thereof are lubricated with a liquid or two-phase fluid maintained by the normal operation tank. During the abnormal operating condition, the plurality of bearings or a portion thereof are lubricated with the fluid in vapor form maintained by the buffer trip tank, Methods that include...

16. The method according to claim 15, comprising supporting the rotor load of the rotor via at least one two-phase hybrid bearing among the plurality of bearings.

17. The method according to claim 15, comprising switching between the normal operation tank and the buffer trip tank in response to sensor feedback indicating the normal operation state, the abnormal operation state, or both.

18. The method according to claim 17, comprising controlling a rapid-acting solenoid valve to switch between the normal-acting tank and the buffer tank in response to sensor feedback.

19. The method according to claim 15, comprising enabling the use of the buffer trip tank and disabling the use of the normal operation tank during the abnormal operating condition via one or more check valves.

20. The method according to claim 15, comprising preventing the buffer trip tank from being pressurized by the normal operating tank via one or more check valves.

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