Economizer flow and inlet guide VANE configurations for refrigerant compressor

Abstract

A refrigerant compressor may include a motor. The refrigerant compressor may include a first compression stage, a second compression stage, and a third compression stage. The refrigerant compressor may further include a first economizer port and a second economizer port. Further, the refrigerant compressor may include two sets of inlet guide vanes.

Description

ECONOMIZER FLOW AND INLET GUIDE VANE CONFIGURATIONS FOR REFRIGERANT COMPRESSORBACKGROUND

[0001] Refrigerant compressors are used to circulate refrigerant in a chiller via a refrigerant loop. Refrigerant loops are known to include a compressor, a condenser, an expansion device, and an evaporator. The compressor compresses the fluid, which then travels to the condenser, which in turn cools and condenses the fluid. The refrigerant then goes to the expansion device, which decreases the pressure of the fluid, and to the evaporator, where the fluid is vaporized, completing a refrigeration cycle.SUMMARY

[0002] In some aspects, the techniques described herein relate to a refrigerant compressor, including: a motor; a first compression stage, a second compression stage, and a third compression stage; a first economizer port; and a second economizer port.

[0003] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein the first economizer port is configured to introduce economizer flow into an interstage pipe.

[0004] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein the interstage pipe is coupled to an exterior housing assembly of the refrigerant compressor and is configured to transport refrigerant between compression stages on opposite axial sides of the motor.

[0005] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein: the interstage pipe includes a first section extending radially outward from the exterior housing assembly and substantially perpendicular to an axis of rotation of the motor, and a second section fluidly coupled to the first section and extending substantiallyparallel to the axis, and the first economizer port is arranged adjacent an intersection of the first and second sections of the interstage pipe.

[0006] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein the first economizer port is arranged such that refrigerant entering the first economizer port flows substantially parallel to the axis.

[0007] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein the interstage pipe further includes a third section fluidly coupled to the second section and extending radially inward from the second section toward the exterior housing assembly in a direction substantially perpendicular to the axis.

[0008] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein the second economizer port is configured to introduce economizer flow into a return channel between the second and third compression stages.

[0009] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein the second economizer port is configured to direct the economizer flow into the return channel via a plurality of nozzles.

[0010] In some aspects, the techniques described herein relate to a refrigerant compressor, further including: a first set of inlet guide vanes upstream of the first compression stage; and a second set of inlet guide vanes immediately upstream of the second or third compression stage

[0011] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein two of the first, second, and third compression stages are on an opposite axial side of a motor as the other one of the first, second, and third compression stages.

[0012] In some aspects, the techniques described herein relate to a refrigerant compressor, including: a motor; a first compression stage, a second compression stage, and a third compression stage; a first set of inlet guide vanes upstream of the first compression stage;and a second set of inlet guide vanes immediately upstream of the second or third compression stage.

[0013] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein the first and second sets of inlet guide vanes are independently controllable.

[0014] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein two of the first, second, and third compression stages are on an opposite axial side of a motor as the other one of the first, second, and third compression stages.

[0015] In some aspects, the techniques described herein relate to a refrigerant compressor, further including: a first economizer port; and a second economizer port.

[0016] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein: the first economizer port is configured to introduce economizer flow into an interstage pipe, and the second economizer port is configured to introduce economizer flow into a return channel between the second and third compression stages.

[0017] In some aspects, the techniques described herein relate to a method, including: introducing economizer flow into a refrigerant compressor via a first economizer port of the refrigerant compressor, wherein the refrigerant compressor includes a first compression stage, a second compression stage downstream of the first compression stage, and a third compression stage downstream of the second compression stage; and introducing economizer flow into a refrigerant compressor via a second economizer port of the refrigerant compressor.

[0018] In some aspects, the techniques described herein relate to a method, further including: adjusting a first set of inlet guide vanes upstream of the first compression stage; and adjusting a second set of inlet guide vanes immediately upstream of the second or third compression stage.

[0019] In some aspects, the techniques described herein relate to a method, wherein the first and second sets of inlet guide vanes are adjusted independently of one another.

[0020] In some aspects, the techniques described herein relate to a method, wherein refrigerant entering the first economizer port is directed to an interstage pipe, and refrigerant entering the second economizer port is directed into a return channel between the second and third compression stages.

[0021] In some aspects, the techniques described herein relate to a method, wherein: the interstage pipe is coupled to an exterior housing assembly of the refrigerant compressor and is configured to transport refrigerant between compression stages on opposite axial sides of a motor, the interstage pipe includes a first section extending radially outward from the exterior housing assembly and substantially perpendicular to an axis of rotation of the motor, and a second section fluidly coupled to the first section and extending substantially parallel to the axis, and the first economizer port is arranged adjacent an intersection of the first and second sections of the interstage pipe.BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 schematically illustrates a refrigerant system.

[0023] Figure 2 is a cross-sectional view of an example compressor taken along line 2-2 in Figure 3.

[0024] Figure 3 is an exterior view of the example compressor.

[0025] Figure 4 is a perspective view of an exterior of the example compressor.

[0026] Figure 5 is a close-up view of a return channel of the example compressor, and illustrates nozzles configured to expel the economizer flow into the return channel.DETAILED DESCRIPTION

[0027] This disclosure relates generally to economizer flow and inlet guide vane configurations refrigerant compressors, and more particularly to centrifugal refrigerant compressors. In a particular example, the disclosed refrigerant compressor includes three compression stages, two locations for introducing economizer flow, and inlet guide vanes. The assemblies, systems, and methods disclosed herein have been found to increase the capacity of the compressor, delay the onset of surge, and increase compressor unloading, among other benefits.

[0028] Figure 1 illustrates a refrigerant system 10. The refrigerant system 10 includes a main refrigerant loop, or circuit, 12 in communication with a compressor 14, a condenser 16, an evaporator 18, and an expansion device 20. This refrigerant system 10 may be used in a chiller, for example. In that example, a cooling tower may be in fluid communication with the condenser 16. While a particular example of the refrigerant system 10 is shown, this application extends to other refrigerant system configurations, including configurations that do not include a chiller. Further, in Figure 1, a portion of the fluid leaving the condenser 16 may return to the compressor 14 through an economizer 22. Fluid from the economizer 22 is relatively high pressure, and, in this example, is introduced into the compressor 14 at one or more locations in order to cool the flow within the compressor 14 and / or add mass flow within the compressor 14, resulting in energy savings and increased efficiency.

[0029] Figure 2 illustrates, in cross-section, a portion of an example compressor 14, taken along line 2-2 of Figure 3, which is an exterior view of the example compressor 14. Figure 4 is a perspective view of an exterior of the compressor 14. With joint reference to Figures 2-4, the compressor 14 includes an exterior housing assembly 24, which includes a plurality of housing sections. The exterior housing assembly 24 surrounds, among other components, an electric motor 26, a first compression stage 28, a second compression stage 30,and a third compression stage 32. The compressor 14 is a centrifugal compressor, and in particular is configured to compress refrigerant. Therefore, the compressor 14 is a three-stage centrifugal refrigerant compressor.

[0030] The electric motor 26 includes a stator 34 arranged radially outside of a rotor 36. The rotor 36 is connected to a shaft 38, which rotates to drive the first, second, and third compression stages 28, 30, 32. In this disclosure, each compression stage 28, 30, 32 includes a respective impeller 40, 42, 44.

[0031] As shown in Figure 2, the first compression stage 28 is located on a first axial side of the electric motor 26, while the second and third compression stages 30, 32 are located on a second, opposite axial side of the electric motor 26. In other embodiments, two compression stages are located on the first side of the electric motor 26, and a single compression stage is located on the second side of the electric motor 26.

[0032] The shaft 38 and impellers 40, 42, 44 are rotatable by the electric motor 26 about an axis A to compress refrigerant F. The terms axial, radial, and circumferential in this disclosure are used relative to the axis A. The shaft 38 may be rotatably supported by a plurality of bearing assemblies, which in some examples are magnetic bearing assemblies.

[0033] During operation of the compressor 14, refrigerant F flows axially toward the impeller 40 of the first compression stage 28 and is expelled radially outwardly to a diffuser 46 downstream of the impeller 40. The diffuser 46 is arranged radially between the outlet of the impeller 40 and a volute 48.

[0034] Refrigerant F expelled from volute 48 enters an interstage pipe 50. The interstage pipe 50 is configured to transport refrigerant F from the first compression stage 28 to the second compression stage 30. As perhaps best seen in Figures 3 and 4, the interstage pipe 50 is attached to the exterior housing assembly 24. The interstage pipe 50 includes a first section 52 extending radially outward from the exterior housing assembly 24 and substantiallyperpendicular to axis A, a second section 54 fluidly coupled to the first section 52 and extending substantially parallel to the exterior housing assembly 24 and substantially parallel to axis A, and a third section 56 fluidly coupled to the second section 54 and extending radially inward from the second section 54 toward the exterior housing assembly 24, in a direction substantially perpendicular to the exterior housing assembly 24 and substantially perpendicular to axis A.

[0035] With reference back to Figure 2, refrigerant F expelled from the interstage pipe 50 is introduced back into the exterior housing assembly 24 and directed to an inlet of the second compression stage 30. The second compression stage 30 expels refrigerant F, which is turned via a return channel 58 and directed to the third compression stage 32. The third compression stage 32 expels refrigerant F to another volute 60, which expels fluid to a compressor discharge 62, which is perhaps best seen in Figures 3 and 4. Refrigerant F flows from compressor discharge 62 to the condenser 16.

[0036] The compressor 14 includes two locations for introducing economizer flow, which is fluid expelled from economizer 22, into the compressor 14. A first location is relative to the interstage pipe 50. A second location is relative to the return channel 58.

[0037] The first location, in this example, includes the first economizer port 64. The first economizer port 64 is arranged adjacent an intersection of the first and second sections 52, 54 of the interstage pipe 50. Further, the first economizer port 64 is configured to introduce refrigerant into the interstage pipe 50 in direction D which is substantially parallel to second section 54 and substantially parallel to axis A, which reduces pressure losses when mixing the economizer flow with the flow already in the interstage pipe 50.

[0038] The second economizer port 66 (Figures 3 and 4) is formed in exterior housing assembly 24 between the second and third compression stages 30, 32, in this example.The economizer port 66 is configured to receive economizer flow and direct it to a plurality ofnozzles 68 (Figure 5) configured to expel the economizer flow from the port 66 into the return channel 58.

[0039] In the above-mentioned embodiment where there are two compression stages (i.e., the first and second compression stages 28, 30) located on the first side of the electric motor 26, and a single compression stage (i.e., the third compression stage 32) located on the second side of the electric motor 26, there is a return channel similar to return channel 58 between the first and second compression stages 28, 30, and the economizer port 66 is configured to receive economizer flow and direct it into the return channel between the first and second stages 28, 30, such as via nozzles similar to nozzles 68.

[0040] While the compressor 14 includes two economizer ports 64, 66, the compressor 14 could include only one of the economizer ports 64, 66.

[0041] With reference to Figure 2, the compressor 14 further includes two sets of inlet guide vanes. A first set of inlet guide vanes 70 is arranged upstream of the first compression stage 28. A control assembly 72, including a controller and one or more actuators, is configured to adjust a rotational position of the inlet guide vanes 70.

[0042] A second set of inlet guide vanes 74 is arranged downstream of the interstage pipe 50 and immediately upstream of the second compression stage 30 (i.e., adjacent the inlet of the second compression stage 30). The control assembly 72 is configured to adjust the rotational position of the inlet guide vanes 74. The control assembly 72 is configured to independently adjust the position of the inlet guide vanes 70, 74. In this way, the flow of refrigerant F entering the first and second compression stages 28, 30 can be controlled independently.

[0043] In the above-mentioned embodiment where there are two compression stages (i.e., the first and second compression stages 28, 30) located on the first side of the electric motor 26, and a single compression stage (i.e., the third compression stage 32) locatedon the second side of the electric motor 26, the second set of inlet guide vanes 74 is located downstream of the interstage pipe 50 and immediately upstream of the third compression stage 32 (i.e., adjacent the inlet of the third compression stage 32).

[0044] It should be understood that terms such as “axial,” “radial,” and “circumferential” are used above with reference to the normal operational attitude of the compressor 14. Further, these terms have been used herein for purposes of explanation, and should not be considered otherwise limiting. Terms such as “generally,” “substantially,” and “about” are not intended to be boundaryless terms, and should be interpreted consistent with the way one skilled in the art would interpret those terms.

[0045] Although the different examples have the specific components shown in the illustrations, embodiments of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from one of the examples in combination with features or components from another one of the examples. In addition, the various figures accompanying this disclosure are not necessarily to scale, and some features may be exaggerated or minimized to show certain details of a particular component or arrangement.

[0046] One of ordinary skill in this art would understand that the above-described embodiments are exemplary and non-limiting. That is, modifications of this disclosure would come within the scope of the claims. Accordingly, the following claims should be studied to determine their true scope and content.

Claims

CLAIMS1. A refrigerant compressor, comprising: a motor; a first compression stage, a second compression stage, and a third compression stage; a first economizer port; and a second economizer port.

2. The refrigerant compressor as recited in claim 1, wherein the first economizer port is configured to introduce economizer flow into an interstage pipe.

3. The refrigerant compressor as recited in claim 2, wherein the interstage pipe is coupled to an exterior housing assembly of the refrigerant compressor and is configured to transport refrigerant between compression stages on opposite axial sides of the motor.

4. The refrigerant compressor as recited in claim 3, wherein: the interstage pipe includes a first section extending radially outward from the exterior housing assembly and substantially perpendicular to an axis of rotation of the motor, and a second section fluidly coupled to the first section and extending substantially parallel to the axis, and the first economizer port is arranged adjacent an intersection of the first and second sections of the interstage pipe.

5. The refrigerant compressor as recited in claim 4, wherein the first economizer port is arranged such that refrigerant entering the first economizer port flows substantially parallel to the axis.

6. The refrigerant compressor as recited in claim 4, wherein the interstage pipe further includes a third section fluidly coupled to the second section and extending radially inward from the second section toward the exterior housing assembly in a direction substantially perpendicular to the axis.

7. The refrigerant compressor as recited in claim 1, wherein the second economizer port is configured to introduce economizer flow into a return channel between the second and third compression stages.

8. The refrigerant compressor as recited in claim 7, wherein the second economizer port is configured to direct the economizer flow into the return channel via a plurality of nozzles.

9. The refrigerant compressor as recited in claim 1, further comprising: a first set of inlet guide vanes upstream of the first compression stage; and a second set of inlet guide vanes immediately upstream of the second or third compression stage10. The refrigerant compressor as recited in claim 1, wherein two of the first, second, and third compression stages are on an opposite axial side of a motor as the other one of the first, second, and third compression stages.

11. A refrigerant compressor, comprising: a motor; a first compression stage, a second compression stage, and a third compression stage; a first set of inlet guide vanes upstream of the first compression stage; and a second set of inlet guide vanes immediately upstream of the second or third compression stage.

12. The refrigerant compressor as recited in claim 11, wherein the first and second sets of inlet guide vanes are independently controllable.

13. The refrigerant compressor as recited in claim 11, wherein two of the first, second, and third compression stages are on an opposite axial side of a motor as the other one of the first, second, and third compression stages.

14. The refrigerant compressor as recited in claim 11, further comprising: a first economizer port; and a second economizer port.

15. The refrigerant compressor as recited in claim 14, wherein: the first economizer port is configured to introduce economizer flow into an interstage pipe, and the second economizer port is configured to introduce economizer flow into a return channel between the second and third compression stages.

16. A method, comprising: introducing economizer flow into a refrigerant compressor via a first economizer port of the refrigerant compressor, wherein the refrigerant compressor includes a first compression stage, a second compression stage downstream of the first compression stage, and a third compression stage downstream of the second compression stage; and introducing economizer flow into a refrigerant compressor via a second economizer port of the refrigerant compressor.

17. The method as recited in claim 16, further comprising: adjusting a first set of inlet guide vanes upstream of the first compression stage; and adjusting a second set of inlet guide vanes immediately upstream of the second or third compression stage.

18. The method as recited in claim 17, wherein the first and second sets of inlet guide vanes are adjusted independently of one another.

19. The method as recited in claim 16, wherein refrigerant entering the first economizer port is directed to an interstage pipe, and refrigerant entering the second economizer port is directed into a return channel between the second and third compression stages.

20. The method as recited in claim 19, wherein: the interstage pipe is coupled to an exterior housing assembly of the refrigerant compressor and is configured to transport refrigerant between compression stages on opposite axial sides of a motor,the interstage pipe includes a first section extending radially outward from the exterior housing assembly and substantially perpendicular to an axis of rotation of the motor, and a second section fluidly coupled to the first section and extending substantially parallel to the axis, and the first economizer port is arranged adjacent an intersection of the first and second sections of the interstage pipe.

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