EP3592986A1

EP3592986A1 - Collector for a compressor

Info

Publication number: EP3592986A1
Application number: EP18712410.2A
Authority: EP
Inventors: Paul W SNELL
Original assignee: Johnson Controls Technology Co
Current assignee: Johnson Controls Technology Co
Priority date: 2017-03-09
Filing date: 2018-03-08
Publication date: 2020-01-15
Also published as: CN110603382A; JP2020510152A; TW201839318A; US20200018325A1; KR20190121846A; WO2018165471A1

Abstract

Embodiments of the present disclosure are directed toward a compressor including an impeller configured to compress a working fluid, a diffuser positioned downstream of the impeller with respect to a flow path of the working fluid, where the diffuser is configured to direct the working fluid through a radial passage, and where the diffuser comprises a vaned diffuser portion disposed within the radial passage, and a collector positioned downstream of the diffuser with respect to the flow path of the working fluid, where a chamber of the collector is axially offset from the radial passage of the diffuser.

Description

COLLECTOR FOR A COMPRESSOR

BACKGROUND

[0001] This application relates generally to vapor compression systems incorporated in air conditioning and refrigeration applications, and, more particularly, to a collector for a compressor.

[0002] Vapor compression systems are utilized in residential, commercial, and industrial environments to control environmental properties, such as temperature and humidity, for occupants of the respective environments. The vapor compression system circulates a working fluid, typically referred to as a refrigerant, which changes phases between vapor, liquid, and combinations thereof in response to being subjected to different temperatures and pressures associated with operation of the vapor compression system. For example, the vapor compression system utilizes a compressor to circulate the refrigerant to a heat exchanger which may transfer heat between the refrigerant and another fluid flowing through the heat exchanger. Unfortunately, vapor compression systems may include a relatively large footprint which may result from the use of relatively large components used to achieve a desired flow capacity.

SUMMARY

[0003] In one embodiment, a compressor includes an impeller configured to compress a working fluid, a diffuser positioned downstream of the impeller with respect to a flow path of the working fluid, where the diffuser is configured to direct the working fluid through a radial passage, and where the diffuser comprises a vaned diffuser portion disposed within the radial passage, and a collector positioned downstream of the diffuser with respect to the flow path of the working fluid, where a chamber of the collector is axially offset from the radial passage of the diffuser.

[0004] In another embodiment, a compressor for a heating, ventilating, air conditioning, and refrigeration (HVAC&R) unit includes an impeller configured to compress a refrigerant, a diffuser positioned downstream of the impeller with respect to a flow path of the refrigerant, where the diffuser is configured to direct the refrigerant through a radial passage, and where the diffuser comprises a variable geometry diffuser ring portion and a vaned diffuser portion disposed within the radial passage, and a collector positioned downstream of the diffuser with respect to the flow path of the refrigerant, where a chamber of the collector axially offset from the radial passage of the diffuser.

[0005] In another embodiment, a heating, ventilating, air conditioning, and refrigeration (HVAC&R) system includes a heat exchanger configured to place a refrigerant in thermal communication with a working fluid and a compressor configured to circulate the refrigerant through the heat exchanger. The compressor includes an impeller configured to compress the refrigerant, a diffuser positioned downstream of the impeller with respect to a flow path of the refrigerant, where the diffuser is configured to direct the refrigerant through a radial passage, and a collector positioned downstream of the diffuser with respect to the flow path of the refrigerant, where a chamber of the collector is axially offset from the radial passage of the diffuser.

DRAWINGS

[0006] FIG. 1 is a perspective view of an embodiment of a building that may utilize a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system in a commercial setting, in accordance with an aspect of the present disclosure;

[0007] FIG. 2 is a perspective view of a vapor compression system, in accordance with an aspect of the present disclosure;

[0008] FIG. 3 is a schematic of an embodiment of the vapor compression system of FIG. 2, in accordance with an aspect of the present disclosure;

[0009] FIG. 4 is a schematic of an embodiment of the vapor compression system of FIG. 2, in accordance with an aspect of the present disclosure;

[0010] FIG. 5 is a cross-section of an embodiment of a collector for a compressor that may be included in the systems of FIGS. 1-4, in accordance with an aspect of the present disclosure; [0011] FIG. 6 is an elevation view of a vaned diffuser portion of the compressor of FIG. 5, in accordance with an aspect of the present disclosure; and

[0012] FIG. 7 is a perspective view of the vaned diffuser portion of FIG. 6, in accordance with an aspect of the present disclosure.

DETAILED DESCRIPTION

[0013] 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.

[0014] Embodiments of the present disclosure are directed towards a heating, ventilating, air conditioning, and refrigeration (HVAC&R) system that uses a compressor to circulate refrigerant through a refrigerant loop. The compressor may be coupled to a condenser of the HVAC&R system along the refrigerant loop. The compressor may compress the refrigerant to increase a pressure of the refrigerant and direct the refrigerant to the condenser. The refrigerant may flow towards the condenser of the HVAC&R system where it may transfer thermal energy to a working fluid in the condenser. The HVAC&R system may also include an evaporator, an expansion valve, and/or other components that generally cause the HVAC&R system to have a relatively large footprint. As such, it is now recognized that modifying existing features of components of the HVAC&R system may reduce an overall size of the HVAC&R system.

[0015] In some cases, the compressor of the HVAC&R system includes a collector, which is positioned downstream from an impeller and/or a diffuser of the compressor with respect to a flow path of the refrigerant. The collector may then further diffuse the refrigerant and ultimately direct the refrigerant toward a discharge port of the compressor. Existing collectors are generally positioned radially outward from the diffuser of the compressor. Further, existing collectors circumferentially surround the entire diffuser, and thus, the impeller of the compressor. In other words, an inlet to the collector is radially aligned with an outlet of the diffuser, such that a chamber of the collector extends radially outward from the outlet of the diffuser. It is now recognized that axially offsetting the collector from the diffuser may reduce a diameter of the compressor, thereby reducing a size of the compressor.

[0016] In some embodiments, axially offsetting the collector from the diffuser may alter a flow of refrigerant from the diffuser to the collector. As such, a cross-sectional area of the chamber of the collector may be adjusted to enable the collector to sufficiently diffuse the refrigerant, while increasing a pressure rise of the refrigerant flowing from the diffuser to the collector. As such, an aspect ratio of the cross section of the collector may be within a target range to enable the compressor to increase or maintain an efficiency when compared to existing compressors. Further, the diffuser section of the compressor may include a variable geometry diffuser ring and/or a vaned diffuser to guide the flow of refrigerant through a passage of the diffuser and further increase the pressure rise of the refrigerant, thereby enabling a size of the collector to be further reduced. As such, a size of the compressor may be reduced, and thus, an overall footprint of the HVAC&R system is also reduced.

[0017] Turning now to the drawings, FIG. 1 is a perspective view of an embodiment of an environment for a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system 10 in a building 12 for a typical commercial setting. The HVAC&R system 10 may include a vapor compression system 14 that supplies a chilled liquid, which may be used to cool the building 12. The HVAC&R system 10 may also include a boiler 16 to supply warm liquid to heat the building 12 and 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 chilled liquid 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.

[0018] FIGS. 2 and 3 are embodiments of the vapor compression system 14 that can be used in the 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 device(s) 36, and a liquid chiller or an evaporator 38. The vapor compression system 14 may further include a control panel 40 that has an analog to digital (AID) converter 42, a microprocessor 44, a non-volatile memory 46, and/or an interface board 48.

[0019] Some examples of fluids that may be used as refrigerants in the vapor compression system 14 are hydrofluorocarbon (HFC) based refrigerants, for example, R- 41 OA, R-407, R-134a, hydrofluoro olefin (HFO), "natural" refrigerants like ammonia ( H₃), R-717, carbon dioxide (CO2), R-744, or hydrocarbon based 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 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 refrigerant, such as R-134a. As used herein, "normal boiling point" may refer to a boiling point temperature measured at one atmosphere of pressure.

[0020] 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 and may be powered by a variable speed drive (VSD) 52. The VSD 52 receives alternating current (AC) power having 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.

[0021] The compressor 32 compresses a refrigerant vapor and delivers the vapor to the condenser 34 through a discharge passage. In some embodiments, the compressor 32 may be a centrifugal or mixed-flow compressor. The refrigerant 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 refrigerant vapor may condense to a refrigerant liquid in the condenser 34 as a result of thermal heat transfer with the cooling fluid. The liquid refrigerant 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.

[0022] The liquid refrigerant delivered to the evaporator 38 may absorb heat from another cooling fluid, which may or may not be the same cooling fluid used in the condenser 34. The liquid refrigerant in the evaporator 38 may undergo a phase change from the liquid refrigerant to a refrigerant 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 a cooling load 62. The cooling 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 cooling fluid in the tube bundle 58 via thermal heat transfer with the refrigerant. 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 refrigerant exits the evaporator 38 and returns to the compressor 32 by a suction line to complete the cycle. [0023] FIG. 4 is a schematic of the vapor compression system 14 with an intermediate circuit 64 incorporated between 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 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. Additionally, the intermediate vessel 70 may provide for further expansion of the liquid refrigerant because of a pressure drop experienced by the liquid refrigerant when entering the intermediate vessel 70 (e.g., due to a rapid increase in volume experienced when entering the intermediate vessel 70). The vapor 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 in the intermediate vessel may be drawn to an intermediate stage of the compressor 32 (e.g., not the suction stage). The liquid that collects in the intermediate vessel 70 may be at a lower enthalpy than the liquid refrigerant exiting the condenser 34 because of the expansion in the expansion device 66 and/or the intermediate vessel 70. The liquid from intermediate vessel 70 may then flow in line 72 through a second expansion device 36 to the evaporator 38.

[0024] As noted above, existing compressors may include a volute or a collector (e.g., a dump collector) that includes an inlet radially aligned with an outlet of a diffuser. It is now recognized that such a configuration increases a diameter of the compressor, thereby increasing an overall footprint of an HVAC&R system that includes the compressor. As such, embodiments of the present disclosure are directed to compressors that include a collector having an inlet that is axially offset from the outlet of the diffuser (e.g., a folded collector). As used herein, a folded collector refers to a collector having an inner chamber that is axially offset from a passage (e.g., a radial passage) of a diffuser of the compressor. In some embodiments, a cross section of the folded collector may include an aspect ratio that increases the pressure rise of the compressor by appropriately guiding the flow of refrigerant as it travels from the diffuser into the collector and/or through the collector. Additionally or alternatively, the diffuser may include a vaned diffuser portion that further increases the pressure rise of the refrigerant as it flows through the diffuser toward the collector. As such, a size of the collector may be further reduced, thereby decreasing a size of the compressor.

[0025] For example, FIG. 5 is a cross section of an embodiment of the compressor 32 having a folded collector 100. As shown in the illustrated embodiment of FIG. 5, the compressor 32 includes an impeller 102 configured to rotate about an axis 104 to drive refrigerant from a suction portion 106 of the compressor 32 toward a diffuser 108. The impeller 102 transfers kinetic energy to the refrigerant, thereby enabling the refrigerant to flow toward and through the diffuser 108. The diffuser 108 then guides the refrigerant toward the folded collector 100 and transforms the kinetic energy of the refrigerant into potential energy, by increasing a pressure of the refrigerant. In some embodiments, the diffuser 108 may include a variable geometry diffuser ring portion 110 and/or a vaned diffuser portion 112. For example, the variable geometry diffuser ring portion 110 may include a ring 114 which may extend axially into a passage 116 of the diffuser 108, thereby partially blocking a flow of the refrigerant from the impeller 102 toward the folded collector 100. The ring 114 may extend into the passage 116 when the compressor 32 operates at partial capacity (e.g., less than 100% capacity), and a position of the ring 114 may depend at least on a flow of the refrigerant through the compressor 32. Additionally or alternatively, a position of the ring 114 within the passage 116 adjusts the flow of refrigerant through the compressor 32, and thus, a pressure of the refrigerant discharged from the compressor 32. In some embodiments, the position of the ring 114 is adjusted by the control system 40 or another suitable controller. In some embodiments, the passage 116 includes a length 117 extending from the impeller 102 toward the folded collector 100. At some conditions, the variable geometry diffuser ring portion 110 and/or vaned diffuser portion 112 may be used to maintain a substantially stable pressure rise of the refrigerant as the refrigerant flows along the length 117 of the passage 116. [0026] Further, the position of the ring 114 may be adjusted (e.g., via a signal sent from the control system 40 to an actuator) to adjust a flow angle of the refrigerant directed toward the vaned diffuser portion 112. As discussed in further detail herein with reference to FIGS. 6 and 7, the vaned diffuser portion 112 may include vanes that are configured to turn as the refrigerant flows through the vaned diffuser portion 112. The vanes of the vaned diffuser portion 112 guide the flow of the refrigerant within the passage 116, thereby increasing the pressure rise of the refrigerant flowing through the diffuser 108. In some embodiments, the pressure increase of the refrigerant caused by the vaned diffuser portion 112 may be based on the flow angle of the refrigerant directed from the variable geometry diffuser ring portion 110 to the vaned diffuser portion 112. For example, adjusting a flow angle of the refrigerant to be substantially equal to an incidence angle of a leading edge of the vanes may increase the efficiency of the compression stage.

[0027] In some embodiments, the variable geometry diffuser ring portion 110 and the vaned diffuser portion 112 may sufficiently increase the pressure rise of the refrigerant through the diffuser 108 such that a diameter 118 of the passage 116 may be reduced, thereby decreasing the overall size of the compressor 32.

[0028] As shown in the illustrated embodiment of FIG. 5, the folded collector 100 includes an inlet 120 that is axially offset from an outlet 122 of the diffuser 108. Accordingly, the folded collector 100 is axially offset from the radial passage 116 by a distance 123. Accordingly, an interface 124 between the inlet 120 and the outlet 122 may form a bend 125 (e.g., a curved passage) that guides the refrigerant from the outlet 122 to the inlet 120. Refrigerant may flow through the inlet 120 toward a chamber 126 of the folded collector 100. In some embodiments, the chamber 126 is axially offset from the diffuser 108. In other words, the portion 128 of the chamber 126 is positioned adjacent to at least a portion 130 of the diffuser 108 with respect to the axis 104. As such, a diameter of the compressor 32 may be reduced when compared to existing compressors that include a collector that is radially aligned with the diffuser 108 with no axial offset.

[0029] In some embodiments, dimensions of the chamber 126 of the folded collector 100 are selected to account for a shift in a direction of flow of the refrigerant from the outlet of refrigerant is configured to flow in a radial direction 132 through the diffuser 108 and enters the inlet 120 of the folded collector 100 in an axial direction 134. As such, dimensions of the chamber 126 of the folded collector 100 may be configured to maintain the pressure rise achieved by the diffuser section 108 while reducing the overall diameter of the compressor 32.

[0030] As shown in the illustrated embodiment of FIG. 5, the chamber 126 is defined by an axial length 136 and a radial length 138. In other embodiments, the chamber 126 may be further defined by other suitable dimensions in addition to, or in lieu of, the axial length 136 and the radial length 138. As used herein, the axial length 136 refers to a distance between a wall 140 separating the chamber 126 from the diffuser 108 and an outermost point 142 of a concave wall 144 that forms the chamber 126. Additionally, the radial length 138 refers to a distance between a first connecting wall 146 (e.g., a first axial connecting wall) and a second connecting wall 148 (e.g., a second axial connecting wall). The first connecting wall 146 couples the concave wall 144 to the wall 140, whereas the second connecting wall 148 couples the concave wall 144 to an interface wall 150 that at least partially defines the interface 124 between the outlet 122 of the diffuser 108 and the inlet 120 of the collector 100. Collectively, the wall 140, the concave wall 144, the first connecting wall 146, and the second connecting wall 148 form the chamber 126 of the folded collector 100. While the illustrated embodiment of FIG. 5 shows the chamber 126 having a cross-sectional shape that is substantially elliptical, it should be understood that the chamber 126 may include any cross-sectional shape that provides a suitable collection volume.

[0031] An aspect ratio of the axial length 136 to the radial length 138 may vary widely depending on the particular embodiment. The aspect ratio may be defined by the axial length 136 and the radial length 138 and may be utilized to maintain the pressure rise achieved by the diffuser section 108 within the folded collector 100. As used herein, the aspect ratio refers to a ratio of the axial length 136 to the radial length 138. The aspect ratio may be between 0.5: 1 and 5: 1, between 0.75: 1 and 3 : 1, or between 1 : 1 and 3 : 1. For instance, in some embodiments, the aspect ratio may be substantially (e.g., within 10% of, within 5% of, or within 1% of) 1 : 1. In any case, the aspect ratio may be selected to maintain or increase a pressure rise of the refrigerant flowing through folded collector 100.

[0032] As discussed above, the diffuser 108 may include the vaned diffuser portion 112, which may include multiple vanes 160 that rotate to adjust the angle of the refrigerant flowing through the passage 116 of the diffuser 108. For example, FIGS. 6 and 7 illustrate embodiments of the vaned diffuser portion 112 having a plurality of the vanes 160 and that may be disposed within the passage 116 of the diffuser 108. The number of diffuser vanes may vary depending on the specific embodiment. While the vaned diffuser portion 112 includes fifteen of the vanes 160, in other embodiments, the vaned diffuser portion 112 includes one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, or more than fifteen of the vanes 160.

[0033] In any case, each of the vanes 160 protrude from a surface 162 of the vaned diffuser portion 112. Additionally or alternatively, the surface 162 may include the ring 114 of the variable geometry diffuser ring portion 110. In any case, the refrigerant flowing through the passage 116 contacts a leading edge 164 of each of the vanes 160. The plurality of vanes 160 increases pressure recovery of the refrigerant through the relatively narrow flow path between the impeller 102 and the folded collector 100. Accordingly, the radial length 138 of the folded collector 100 may be decreased as a result of the increased pressure recovery caused by the vaned diffuser portion 112. Therefore, the size of the compressor 32 and/or the HVAC&R system may also be reduced.

[0034] In some embodiments, a position of the variable geometry diffuser ring portion 110 may enable a flow angle of the refrigerant to be substantially equal to an incidence 166 of the leading edge 164 of the vanes 160 of the vaned diffuser portion 112. For instance, a control system, such as the control system 40, may adjust a position of the ring 114 of the variable geometry diffuser ring portion 110 within the passage 116 to adjust a flow angle of the refrigerant downstream of the ring 114. In some embodiments, the position of the ring 114 may be adjusted to achieve the flow angle based on a target flow of the refrigerant entering the compressor 32, a discharge pressure of the refrigerant exiting the compressor 32, a speed at which the motor 50 drives the impeller 102, and/or another suitable parameter. As such, the control system 40 may receive feedback indicative of one or more parameters and adjust the position of the ring 114 within the passage 116 to achieve the flow angle of refrigerant that is substantially equal to (e.g., within 10% of, within 5% of, or within 1% of) the incidence 166 of the leading edge 164 of the vanes 160. Further, the folded collector 100 in combination with the diffuser 108 having both the variable geometry diffuser ring portion 1 10 and the vaned diffuser portion 112 reduces a size of the compressor, and thus the HVAC&R system.

[0035] As set forth above, the present disclosure may provide one or more technical effects useful in reducing a size of an HVAC&R system. Embodiments of the disclosure may include a compressor that includes a folded collector. The folded collector may be axially offset from an outlet of a diffuser of the compressor, which may reduce a diameter of the compressor. Further, the diffuser may include a variable geometry diffuser ring portion and/or a vaned diffuser portion that increases the pressure rise of the refrigerant flowing through the diffuser. As such, the radial length of the diffuser of the folded collector may be reduced, which further reduces a size of the compressor. The technical effects and technical problems in the specification are examples and are not limiting. It should be noted that the embodiments described in the specification may have other technical effects and can solve other technical problems.

[0036] While only certain features and embodiments have been illustrated and described, many modifications and changes may occur to those skilled in the art (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters (e.g., temperatures, pressures, etc.), mounting arrangements, use of materials, colors, orientations, etc.) 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. Furthermore, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not have been described (i.e., those unrelated to the presently contemplated best mode of carrying out the disclosure, or those unrelated to enabling the claimed disclosure). 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.

Claims

CLAIMS:

1. A compressor, comprising:

an impeller configured to compress a working fluid;

a diffuser positioned downstream of the impeller with respect to a flow path of the working fluid, wherein the diffuser is configured to direct the working fluid through a radial passage, and wherein the diffuser comprises a vaned diffuser portion disposed within the radial passage; and

a collector positioned downstream of the diffuser with respect to the flow path of the working fluid, wherein a chamber of the collector is axially offset from the radial passage of the diffuser.

2. The compressor of claim 1, wherein the diffuser comprises a variable geometry diffuser ring portion disposed within the radial passage.

3. The compressor of claim 2, wherein the variable geometry diffuser ring portion comprises a ring configured to extend axially into the radial passage to adjust a flow of the working fluid through the radial passage.

4. The compressor of claim 3, wherein the vaned diffuser portion is positioned downstream of the variable geometry diffuser ring portion with respect to the flow path of the working fluid, and wherein a position of the ring of the variable geometry diffuser ring portion is configured to adjust a flow angle of the working fluid directed toward the vaned diffuser portion.

5. The compressor of claim 1, comprising an interface positioned between an outlet of the diffuser and an inlet of the collector with respect to the flow path of the working fluid.

6. The compressor of claim 5, wherein the interface comprises a bend configured to adjust a direction of the flow path of the working fluid.

7. The compressor of claim 5, wherein the outlet of the diffuser and the inlet of the collector are axially offset from one another.

8. The compressor of claim 5, wherein the outlet of the diffuser and the inlet of the collector are not radially aligned with one another.

9. The compressor of claim 1, wherein the chamber of the collector is defined by an axial length and a radial length, and wherein the axial length and the radial length define an aspect ratio of the chamber.

10. A compressor for a heating, ventilation, air conditioning, and refrigeration (HVAC&R) unit, comprising:

an impeller configured to compress a refrigerant;

a diffuser positioned downstream of the impeller with respect to a flow path of the refrigerant, wherein the diffuser is configured to direct the refrigerant through a radial passage, and wherein the diffuser comprises a variable geometry diffuser ring portion and a vaned diffuser portion disposed within the radial passage; and

a collector positioned downstream of the diffuser with respect to the flow path of the refrigerant, wherein a chamber of the collector is axially offset from the radial passage of the diffuser.

11. The compressor of claim 10, wherein the variable geometry diffuser ring portion is positioned upstream of the vaned diffuser portion with respect to the flow path of the refrigerant.

12. The compressor of claim 10, wherein the vaned diffuser portion comprises a plurality of vanes configured to drive rotation of the vaned diffuser portion within the radial passage.

13. The compressor of claim 10, wherein the chamber of the collector is defined by an axial length and a radial length, and wherein the axial length and the radial length define an aspect ratio of the chamber.

14. The compressor of claim 10, wherein an outlet of the diffuser and an inlet of the collector are axially offset from one another.

15. The compressor of claim 10, wherein an outlet of the diffuser and an inlet of the collector are not radially aligned with one another.

16. A heating, ventilation, air conditioning, and refrigeration (HVAC&R) system, comprising:

a compressor configured to circulate the refrigerant through the heat exchanger, wherein the compressor comprises:

an impeller configured to compress the refrigerant;

a diffuser positioned downstream of the impeller with respect to a flow path of the refrigerant, wherein the diffuser is configured to direct the refrigerant through a radial passage; and

a collector positioned downstream of the diffuser with respect to the flow path of the refrigerant, wherein an inlet of the collector is axially offset from an outlet of the radial passage of the diffuser.

17. The system of claim 16, wherein the diffuser comprises a variable geometry diffuser ring portion and a vaned diffuser portion.

18. The system of claim 17, comprising a controller configured to adjust the position of a variable geometry diffuser ring with respect to the radial passage.

19. The system of claim 18, wherein the controller is configured to adjust the position of the ring based on a suction pressure of the refrigerant, a discharge pressure of the refrigerant, a flow rate of the refrigerant through the compressor, or a combination thereof.

20. The system of claim 17, wherein the position of the ring of the variable geometry diffuser ring is configured to direct the refrigerant toward the vaned diffuser portion at a flow angle that is substantially equal to an incidence of a leading edge of a vane of the vaned diffuser portion.