CN110603382A

CN110603382A - Collector for compressor

Info

Publication number: CN110603382A
Application number: CN201880029561.0A
Authority: CN
Inventors: 保罗·W·斯內尔
Original assignee: Johnson Controls Technology Co
Current assignee: Johnson Controls Technology Co
Priority date: 2017-03-09
Filing date: 2018-03-08
Publication date: 2019-12-20
Also published as: KR20190121846A; TW201839318A; US20200018325A1; JP2020510152A; WO2018165471A1; EP3592986A1

Abstract

Embodiments of the present disclosure relate to a compressor including: an impeller configured to compress a working fluid; a diffuser positioned downstream of the impeller relative to a flow path of the working fluid, wherein the diffuser is configured to direct the working fluid through a radial channel, and wherein the diffuser comprises a vaned diffuser portion disposed within the radial channel; and a collector positioned downstream of the diffuser relative to a flow path of the working fluid, wherein a chamber of the collector is axially offset from the radial passage of the diffuser.

Description

Collector for compressor

Background

The present application relates generally to vapor compression systems incorporated in air conditioning and refrigeration applications, and more particularly to an accumulator for a compressor.

Vapor compression systems are used in residential, commercial, and industrial environments to control environmental characteristics, such as temperature and humidity, of occupants of the respective environments. Vapor compression systems circulate a working fluid, typically referred to as a refrigerant, that changes phase between vapor, liquid, and combinations thereof in response to different temperatures and pressures associated with operation of the vapor compression system. For example, vapor compression systems utilize a compressor to circulate a refrigerant to a heat exchanger, which can 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 be the result of using relatively large components to achieve a desired flow rate.

Disclosure of Invention

In one embodiment, a compressor includes: an impeller configured to compress a working fluid; a diffuser positioned downstream of the impeller relative to a flow path of the working fluid, wherein the diffuser is configured to direct the working fluid through a radial channel, and wherein the diffuser comprises a vaned diffuser portion disposed within the radial channel; and a collector positioned downstream of the diffuser relative to a flow path of the working fluid, wherein a chamber of the collector is axially offset from the radial passage of the diffuser.

In another embodiment, a compressor for a heating, ventilation, air conditioning and refrigeration (HVAC & R) unit includes: an impeller configured to compress a refrigerant; a diffuser positioned downstream of the impeller relative to a flow path of the refrigerant, wherein the diffuser is configured to direct the refrigerant through a radial channel, and wherein the diffuser includes a variable geometry diffuser ring portion and a vaned diffuser portion disposed within the radial channel; and an accumulator positioned downstream of the diffuser with respect to a flow path of the refrigerant, wherein a chamber of the accumulator is axially offset from the radial passage of the diffuser.

In another embodiment, a heating, ventilation, 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 relative to a flow path of the refrigerant, wherein the diffuser is configured to direct the refrigerant through radial channels; and an accumulator positioned downstream of the diffuser with respect to a flow path of the refrigerant, wherein a chamber of the accumulator is axially offset from the radial passage of the diffuser.

Drawings

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;

FIG. 2 is a perspective view of a vapor compression system according to one aspect of the present disclosure;

FIG. 3 is a schematic view of an embodiment of the vapor compression system of FIG. 2, according to an aspect of the present disclosure;

FIG. 4 is a schematic view of an embodiment of the vapor compression system of FIG. 2, according to an aspect of the present disclosure;

FIG. 5 is a cross-section of an embodiment of an accumulator of the compressor that may be included in the system of FIGS. 1-4, according to an aspect of the present disclosure;

FIG. 6 is a front view of a vaned diffuser portion of the compressor of FIG. 5 in accordance with an aspect of the present disclosure; and is

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

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.

Embodiments of the present disclosure relate to a heating, ventilation, air conditioning and refrigeration (HVAC & R) system that uses a compressor to circulate a refrigerant through a refrigerant circuit. The compressor may be coupled to a condenser of the HVAC & R system along a refrigerant circuit. The compressor may compress the refrigerant to increase the pressure of the refrigerant and direct the refrigerant to the condenser. The refrigerant may flow toward a condenser of the HVAC & R system where the refrigerant 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 typically provide the HVAC & R system with a relatively large footprint. Thus, it is now recognized that modifications to existing features of HVAC & R system components can reduce the overall size of the HVAC & R system.

In some cases, a compressor of an HVAC & R system includes an accumulator positioned downstream of an impeller and/or a diffuser of the compressor relative to a flow path of the refrigerant. The accumulator may then further diffuse the refrigerant and ultimately direct the refrigerant toward the discharge of the compressor. Typically, the existing collector is positioned radially outward from the diffuser of the compressor. Further, the existing collector circumferentially surrounds the entire diffuser, and thus the impeller of the compressor. In other words, the inlet of the collector is radially aligned with the outlet of the diffuser such that the 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 the diameter of the compressor, thereby reducing the size of the compressor.

In some embodiments, axially offsetting the accumulator from the diffuser may alter the flow of refrigerant from the diffuser to the accumulator. In this way, the cross-sectional area of the chamber of the accumulator may be adjusted to enable the accumulator to adequately diffuse refrigerant while increasing the pressure rise of the refrigerant flowing from the diffuser to the accumulator. In this way, the aspect ratio of the cross-section of the collector may be within a target range to enable the compressor to increase or maintain efficiency when compared to existing compressors. Further, the diffuser portion of the compressor may include a variable geometry diffuser ring and/or a vaned diffuser to direct the refrigerant flow through the passages of the diffuser and further increase the pressure rise of the refrigerant, thereby enabling further reduction in the size of the accumulator. This allows the size of the compressor to be reduced and thus also the overall footprint of the HVAC & R system.

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 that may be used to cool the building 12. The HVAC & R system 10 may also include a boiler 16 for supplying a warm liquid to heat the building 12, and an air distribution system that circulates 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 a conduit 24. The heat exchanger in the air handler 22 may receive heated liquid from the boiler 16 or chilled liquid from the vapor compression system 14, 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 the building 12, but in other embodiments the HVAC & R system 10 may include an air handler 22 and/or other components that are sharable between two or more floors.

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

Some examples of fluids that may be used as the refrigerant in the vapor compression system 14 are Hydrofluorocarbon (HFC) -based refrigerants (e.g., R-410A, R-407, R-134a), Hydrofluoroolefins (HFO), "natural" refrigerants (such as ammonia (NH), for example₃) R-717, carbon dioxide (CO)₂) R-744), or a hydrocarbon based refrigerant, water vapor, or any other suitable refrigerant. In some embodiments, the vapor compression system 14 may be configured to efficiently utilize a refrigerant having a normal boiling point of about 19 degrees celsius (66 degrees fahrenheit) at one atmosphere (relative to an intermediate pressure refrigerant such as R-134a, also referred to as a low pressure refrigerant). As used herein, "normal boiling point" may refer to the boiling point temperature measured at one atmosphere of pressure.

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 device 36, and/or an evaporator 38. The motor 50 may drive the compressor 32 and may be powered by a Variable Speed Drive (VSD) 52. 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 motor 50. In other embodiments, the motor 50 may be powered directly by an AC power source or a Direct Current (DC) power source. The motor 50 may include any type of motor that may 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.

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 due to heat transfer with the cooling fluid. Liquid refrigerant from the condenser 34 may flow through an expansion device 36 to an evaporator 38. In the embodiment illustrated in fig. 3, the condenser 34 is water cooled and includes a tube bundle 54 connected to a cooling tower 56 that supplies a cooling fluid to the condenser.

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 liquid refrigerant to refrigerant vapor. As shown in the embodiment illustrated in 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 (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 a return line 60R and exits the evaporator 38 via a supply line 60S. The evaporator 38 may reduce the temperature of the cooling fluid in the tube bundle 58 by 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 event, vapor refrigerant exits the evaporator 38 and returns to the compressor 32 through a suction line to complete the cycle.

Fig. 4 is a schematic diagram of the vapor compression system 14 with an intermediate circuit 64 coupled between the condenser 34 and the expansion device 36. The intermediate circuit 64 may have an inlet line 68 fluidly connected directly to the condenser 34. In other embodiments, the inlet line 68 may be indirectly fluidly connected to the condenser 34. As shown in the illustrated embodiment of fig. 4, inlet line 68 includes a first expansion device 66 located 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 "surface economizer". In the embodiment illustrated in fig. 4, the intermediate vessel 70 functions as a flash tank, and the first expansion device 66 is configured to reduce the pressure (e.g., expand) 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. In addition, the intermediate container 70 may provide further expansion of the liquid refrigerant due to a pressure drop experienced by the liquid refrigerant upon entering the intermediate container 70 (e.g., due to a rapid increase in volume experienced upon entering the intermediate container 70). 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 container may be drawn to an intermediate stage (e.g., not a suction stage) of the compressor 32. Due to the expansion in the expansion device 66 and/or the intermediate container 70, the liquid collected in the intermediate container 70 may be at a lower enthalpy than the liquid refrigerant exiting the condenser 34. Liquid from the intermediate vessel 70 may then flow into line 72 through the second expansion device 36 to the evaporator 38.

As noted above, existing compressors may include a volute or collector (e.g., a dump collector) that includes an inlet radially aligned with the diffuser outlet. It is now recognized that such a configuration increases the diameter of the compressor, thereby increasing the overall footprint of the HVAC & R system including the compressor. Accordingly, embodiments of the present disclosure relate to compressors that include a collector (e.g., a foldaway collector) having an inlet axially offset from an outlet of a diffuser. As used herein, a foldover collector refers to a collector having an internal chamber that is axially offset from a passage (e.g., a radial passage) of a diffuser of a compressor. In some embodiments, the cross-section of the foldout collector may have an aspect ratio that increases the pressure rise of the compressor by appropriately directing the flow of refrigerant as it travels from the diffuser to 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 towards the collector. This allows a further reduction in the size of the collector and thus of the compressor.

For example, FIG. 5 is a cross-section of an embodiment of a compressor 32 having a foldaway 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 imparts kinetic energy to the refrigerant, thereby enabling the refrigerant to flow toward and through the diffuser 108. The diffuser 108 then directs the refrigerant toward the foldout collector 100 and converts the kinetic energy of the refrigerant into potential energy by increasing the 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 that may extend axially into the channel 116 of the diffuser 108, thereby partially blocking the flow of refrigerant from the impeller 102 toward the foldout collector 100. When the compressor 32 is operating at partial displacement (e.g., less than 100% displacement), the ring 114 may extend into the passage 116, and the position of the ring 114 may depend at least on the flow of refrigerant through the compressor 32. Additionally or alternatively, the position of the ring 114 within the passage 116 adjusts the flow of refrigerant through the compressor 32, and thus the 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 other suitable controller. In some embodiments, the channel 116 includes a length 117 extending from the impeller 102 toward the foldaway collector 100. In some cases, the variable geometry diffuser ring 110 and/or the vaned diffuser portion 112 may be used to maintain a substantially steady pressure rise of the refrigerant as it flows along the length 117 of the channel 116.

Further, the position of the ring 114 may be adjusted (e.g., by a signal sent from the control system 40 to the actuator) to adjust the flow angle of the refrigerant toward the vaned diffuser portion 112. As discussed in further detail herein with reference to fig. 6 and 7, vaned diffuser portion 112 may include vanes configured to rotate as the refrigerant flows through vaned diffuser portion 112. The vanes of vaned diffuser portion 112 direct the flow of refrigerant within passage 116, thereby increasing the pressure rise of the refrigerant flowing through diffuser 108. In some embodiments, the pressure rise 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 110 to the vaned diffuser portion 112. For example, adjusting the flow angle of the refrigerant to be substantially equal to the angle of attack of the leading edges of the vanes may increase the efficiency of the compression stage.

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

As shown in the embodiment illustrated in fig. 5, the foldout collector 100 includes an inlet 120 axially offset from an outlet 122 of the diffuser 108. Accordingly, the foldout collector 100 is axially offset from the radial passage 116 by a distance 123. Accordingly, the interface 124 between the inlet 120 and the outlet 122 may form a bend 125 (e.g., a curved channel) that directs refrigerant from the outlet 122 to the inlet 120. The refrigerant may flow through the inlet 120 toward the chamber 126 of the collapsible collector 100. In some embodiments, the chamber 126 is axially offset from the diffuser 108. In other words, relative to the axis 104, the portion 128 of the chamber 126 is positioned at least adjacent to the portion 130 of the diffuser 108. Thus, the diameter of the compressor 32 may be reduced as compared to prior compressors that included a collector radially aligned with the diffuser 108 in a non-axially offset manner.

In some embodiments, the dimensions of the chamber 126 of the foldout collector 100 are selected to account for displacement in the direction of flow of the refrigerant from the outlet 122 of the diffuser 108 to the inlet 120 of the foldout collector 100. For example, the flow of refrigerant is configured to flow in a radial direction 132 through the diffuser 108 and into the inlet 120 of the foldout collector 100 in an axial direction 134. Accordingly, the size of the chamber 126 of the foldaway collector 100 may be configured to maintain the pressure rise achieved by the diffuser portion 108 while reducing the overall diameter of the compressor 32.

As shown in the embodiment illustrated in fig. 5, the chamber 126 is defined by an axial length 136 and a radial length 138. In other embodiments, other suitable dimensions may be used in addition to or in lieu of axial length 136 and radial length 138 to further define chamber 126. As used herein, the axial length 136 refers to the distance between a wall 140 separating the chamber 126 from the diffuser 108 and an outermost point 142 of a concave wall 144 forming the chamber 126. In addition, the radial length 138 refers to a distance between the first connection wall 146 (e.g., a first axial connection wall) and the second connection wall 148 (e.g., a second axial connection wall). A first connecting wall 146 couples the recess wall 144 to the wall 140, while a second connecting wall 148 couples the recess 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. The wall 140, the recessed wall 144, the first connecting wall 146, and the second connecting wall 148 collectively form the chamber 126 of the collapsible collector 100. While the embodiment illustrated in fig. 5 shows the chamber 126 having a generally elliptical cross-sectional shape, it should be understood that the chamber 126 may comprise any cross-sectional shape that provides a suitable collection volume.

The aspect ratio of axial length 136 to radial length 138 may vary widely depending on the particular embodiment. The aspect ratio may be defined by an axial length 136 and a radial length 138, and may be used to maintain the pressure rise achieved by the diffuser portion 108 within the foldout collector 100. As used herein, aspect ratio refers to the ratio of axial length 136 to 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 example, in some embodiments, the aspect ratio may be about 1:1 (e.g., within 10% thereof, within 5% thereof, or within 1% thereof). In any event, the aspect ratio may be selected to maintain or increase the pressure rise of the refrigerant flowing through the foldout collector 100.

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

In any event, each of these vanes 160 protrudes from a surface 162 of bladed diffuser portion 112. Additionally or alternatively, the surface 162 may comprise the ring 114 of the variable geometry diffuser ring portion 110. In any event, refrigerant flowing through the channel 116 contacts the leading edge 164 of each of the vanes 160. The plurality of vanes 160 enhance pressure recovery of the refrigerant by a relatively narrow flow path between the impeller 102 and the foldaway collector 100. Accordingly, the radial length 138 of the foldaway collector 100 may be reduced as a result of the improved pressure recovery caused by the vaned diffuser portion 112. Accordingly, the size of the compressor 32 and/or the HVAC & R system may also be reduced.

In some embodiments, the position of the variable geometry diffuser ring 110 may be such that the flow angle of the refrigerant is substantially equal to the angle of attack 166 of the leading edges 164 of the vanes 160 of the vaned diffuser portion 112. For example, a control system (e.g., control system 40) may adjust the position of the ring 114 of the variable geometry diffuser ring 110 within the channel 116 to adjust the 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 refrigerant entering the compressor 32, a discharge pressure of refrigerant exiting the compressor 32, a speed at which the motor 50 drives the impeller 102, and/or other suitable parameters. Accordingly, the control system 40 may receive feedback indicative of one or more parameters and adjust the position of the ring 114 within the channel 116 to achieve an angle of flow of the refrigerant that is substantially equal to (e.g., within 10% of, within 5% of, or within 1% of) the angle of attack 166 of the leading edge 164 of the vane 160. Further, the folding collector 100, in combination with the diffuser 108 having both the variable geometry diffuser ring 110 and the vaned diffuser portion 112, reduces the size of the compressor, and thus the HVAC & R system.

As described above, the present disclosure may provide one or more technical effects useful in reducing the size of HVAC & R systems. Embodiments of the present disclosure may include a compressor having a foldaway collector. The foldaway collector may be axially offset from the outlet of the compressor's diffuser, which may reduce the diameter of the compressor. Further, the diffuser may include a variable geometry diffuser ring and/or a vaned diffuser portion that increases the pressure rise of refrigerant flowing through the diffuser. This allows the radial length of the diffuser of the foldaway collector to be reduced, which further reduces the size of the compressor. The technical effects and technical problems in the present specification are exemplary and not restrictive. It should be noted that the embodiments described in the specification may have other technical effects and may solve other technical problems.

Although 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 not 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

1. A compressor, comprising:

an impeller configured to compress a working fluid;

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

a collector positioned downstream of the diffuser relative to a 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 said diffuser includes a variable geometry diffuser ring portion disposed within said radial passage.

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

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

5. The compressor of claim 1, comprising an interface positioned between an outlet of said diffuser and an inlet of said collector relative to a flow path of said working fluid.

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

7. The compressor of claim 5, wherein an outlet of said diffuser and an inlet of said collector are axially offset from each other.

8. The compressor of claim 5, wherein an outlet of said diffuser and an inlet of said collector are not radially aligned with each other.

9. The compressor of claim 1, wherein a chamber of said collector is defined by an axial length and a radial length, and wherein said axial length and said radial length define an aspect ratio of said 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 relative to a flow path of the refrigerant, wherein the diffuser is configured to direct the refrigerant through a radial channel, and wherein the diffuser includes a variable geometry diffuser ring portion and a vaned diffuser portion disposed within the radial channel; and

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

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

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

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

14. The compressor of claim 10, wherein an outlet of said diffuser and an inlet of said collector are axially offset from each other.

15. The compressor of claim 10, wherein an outlet of said diffuser and an inlet of said collector are not radially aligned with each other.

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

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

an impeller configured to compress the refrigerant;

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

an accumulator positioned downstream of the diffuser with respect to a flow path of the refrigerant, wherein an inlet of the accumulator is axially offset from an inlet of the radial passages 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 a position of a variable geometry diffuser ring relative 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 ring of the variable geometry diffuser ring is positioned to direct the refrigerant toward the vaned diffuser portion at a flow angle substantially equal to an angle of attack of leading edges of vanes of the vaned diffuser portion.