CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from and the benefit of U.S. Provisional Application No. 63/353,403, entitled “COMPRESSOR SYSTEM FOR HVAC&R SYSTEM,” filed June 17, 2022, which is herein incorporated by reference in its entirety for all purposes.

BACKGROUND

[0002] This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

[0003] Chiller systems, or vapor compression systems, utilize a working fluid (e.g., a refrigerant) that changes phases between vapor, liquid, and combinations thereof in response to exposure to different temperatures and pressures within components of the chiller system. The chiller system may place the working fluid in a heat exchange relationship with a conditioning fluid (e g., water) and may deliver the conditioning fluid to conditioning equipment and/or a conditioned environment serviced by the chiller system. In some embodiments, the chiller system may include an economizer configured to improve an efficiency of the chiller system. For example, a first heat exchanger (e.g., a condenser) may cool the working fluid and direct the cooled working fluid to the economizer, which may reduce a pressure of the working fluid to further cool the working fluid and separate the working fluid into liquid phase working fluid and vapor phase working fluid. The economizer may direct the liquid phase working fluid to a second heat exchanger (e.g., an evaporator) configured to place the working fluid in the heat exchange relationship with the conditioning fluid. The economizer may direct the vapor phase working fluid to a compressor for pressurization. Unfortunately, existing chiller systems that include economizers may be costly and/or may operate inefficiently.

SUMMARY

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

[0005] In one embodiment, a heating, ventilation, air conditioning, and/or refrigeration (HVAC&R) system includes an economizer configured to receive a heat transfer fluid from a condenser. The economizer is configured to separate the heat transfer fluid into liquid heat transfer fluid and vapor heat transfer fluid. The HVAC&R system includes a low flow compressor configured to receive the vapor heat transfer fluid from the economizer, pressurize the vapor heat transfer fluid, and direct the vapor heat transfer fluid to the condenser.

[0006] In another embodiment, a heating, ventilation, air conditioning, and/or refrigeration (HVAC&R) system includes an economizer configured to separate a heat transfer fluid into liquid heat transfer fluid and vapor heat transfer fluid. The HVAC&R system includes a compressor configured to receive the vapor heat transfer fluid from the economizer. The compressor includes a shaft configured to rotate a plate of the compressor to drive flow of the vapor heat transfer fluid through the compressor via boundary layer effects imparted by a surface of the plate and to pressurize the vapor heat transfer fluid to produce pressurized vapor heat transfer fluid. The compressor is configured to direct the pressurized vapor heat transfer fluid to a heat exchanger of the HVAC&R system. [0007] In another embodiment, a heating, ventilation, air conditioning, and/or refrigeration (HVAC&R) system includes a first compressor configured to direct a heat transfer fluid to a condenser. The HVAC&R system includes an economizer configured to receive the heat transfer fluid from the condenser. The economizer is configured to separate the heat transfer fluid into liquid heat transfer fluid and vapor heat transfer fluid. The HVAC&R system includes a second compressor having a plate and configured to receive the vapor heat transfer fluid from the economizer. The second compressor is configured to rotate the plate to direct the vapor heat transfer fluid to the condenser via boundary layer effects imparted on the vapor heat transfer fluid by a surface of the plate.

DRAWINGS

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

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

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

[0011] FIG. 3 is a schematic of an embodiment of the vapor compression system of FIG. 2, in accordance with an aspect of the present disclosure;

[0012] 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;

[0013] FIG. 5 is a schematic of an embodiment of the vapor compression system of FIG. 2, in accordance with an aspect of the present disclosure; [0014] FIG. 6 is a schematic of an embodiment of a vapor compression system including an economizer and a compressor configured to receive heat transfer fluid from the economizer, in accordance with an aspect of the present disclosure;

[0015] FIG. 7 is a schematic of an embodiment of a vapor compression system including multiple economizers and a compressor configured to receive heat transfer fluid from the economizers, in accordance with an aspect of the present disclosure;

[0016] FIG. 8 is a schematic of an embodiment of a vapor compression system including multiple economizers and a compressor configured to receive heat transfer fluid from the economizers, in accordance with an aspect of the present disclosure; and

[0017] FIG. 9 is a schematic of an embodiment of a vapor compression system including multiple economizers and a compressor configured to receive heat transfer fluid from the economizers, in accordance with an aspect of the present disclosure.

DETAILED DESCRIPTION

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

[0019] When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

[0020] As used herein, the terms “approximately,” “generally,” “substantially,” and so forth, are intended to convey that the property value being described may be within a relatively small range of the property value, as those of ordinary skill would understand. For example, when a property value is described as being “approximately” equal to (or, for example, “substantially similar” to) a given value, this is intended to convey that the property value may be within +/- 5%, within +/- 4%, within +/- 3%, within +/- 2%, within +/- 1%, or even closer, of the given value. Similarly, when a given feature is described as being “substantially parallel” to another feature, “generally perpendicular” to another feature, and so forth, this is intended to convey that the given feature is within +/- 5%, within +/- 4%, within +/- 3%, within +/- 2%, within +/- 1%, or even closer, to having the described nature, such as being parallel to another feature, being perpendicular to another feature, and so forth. Mathematical terms, such as “parallel” and “perpendicular,” should not be rigidly interpreted in a strict mathematical sense, but should instead be interpreted as one of ordinary skill in the art would interpret such terms. For example, one of ordinary skill in the art would understand that two lines that are substantially parallel to each other are parallel to a substantial degree, but may have minor deviation from exactly parallel.

[0021] Embodiments of the present disclosure relate to a heating, ventilation, air conditioning, and/or refrigeration (HVAC&R) system having a vapor compression system (e.g., vapor compression circuit). The vapor compression system may include a compressor (e.g., a primary compressor) configured to pressurize a heat transfer fluid (e g., refrigerant) within the vapor compression system and direct the heat transfer fluid to a condenser, which may cool and condense the heat transfer fluid. The condensed heat transfer fluid may be directed toward an expansion device, which may reduce a pressure of the heat transfer fluid, further cooling the heat transfer fluid. From the expansion device, the cooled heat transfer fluid may be directed to an evaporator, where the heat transfer fluid may be placed in a heat exchange relationship with a conditioning fluid to cool the conditioning fluid. The compressor may then receive the heat transfer fluid from the evaporator for pressurization to restart the vapor compression cycle.

[0022] In some embodiments, the vapor compression system may include an economizer configured to receive the heat transfer fluid from the condenser. The economizer may be configured to reduce a pressure of the heat transfer fluid and separate the heat transfer fluid into liquid heat transfer fluid (e.g., a first fractional percentage) and vapor heat transfer fluid (e.g., a second fractional percentage equal to 1 minus the first fractional percentage). The economizer may direct the liquid heat transfer fluid to the evaporator to enable the evaporator to place the liquid heat transfer fluid in a heat exchange relationship with the conditioning fluid. The vapor heat transfer fluid may be directed from the economizer toward the condenser and through a compressor. However, because the pressure of the heat transfer fluid (e.g., of the vapor heat transfer fluid) in the condenser may be higher than the pressure of the heat transfer fluid (e.g., of the vapor heat transfer fluid) in the economizer, the vapor heat transfer fluid directed from the economizer may not readily flow to or through (e.g., directly to, directly through) the condenser in some circumstances That is, the pressure differential between the heat transfer fluid in the condenser and in the economizer may block natural flow of the heat transfer fluid from the economizer directly to the condenser (e.g., without pressurization of the heat transfer fluid at the economizer). Additionally, the vapor heat transfer fluid directed from the economizer may combine with the heat transfer fluid pressurized by the compressor, but the respective heat transfer fluid flows may be at different pressures. The pressure differential between the heat transfer fluid flows may disrupt flow of the heat transfer fluid to and/or through the condenser. For instance, the pressure differential may cause backflow of heat transfer fluid in a direction associated with lower heat transfer fluid pressure (e.g., toward the compressor, toward the economizer) instead of to and/or through the condenser. [0023] Thus, it is now recognized that improvements are desired for HVAC&R systems having one or more economizers, such as to pressurize the vapor heat transfer fluid that may be directed from the economizer and that may be of relatively low flow (e.g., pressure, mass flow) as compared to the heat transfer fluid directed from the condenser and/or from the evaporator. Accordingly, the present disclosure is directed to incorporating an additional, auxiliary compressor configured to receive vapor heat transfer fluid from an economizer, pressurize the vapor heat transfer fluid, and direct the pressurized vapor heat transfer fluid toward the condenser. The auxiliary compressor may pressurize the vapor heat transfer fluid toward the pressure of the heat transfer fluid pressurized by the compressor (e.g., the primary compressor). Therefore, the auxiliary compressor may reduce a pressure differential between the respective heat transfer fluid flows directed to and/or through the condenser and/or reduce a flow of heat transfer fluid through the compressor (e.g., the primary compressor), thereby improving efficiency of the HVAC&R system, such as by reducing a total power used to perform cooling or heating via the heat transfer fluid at the evaporator or the condenser, respectively.

[0024] A cost and/or complexity associated with manufacture and/or operation of the auxiliary compressor may be less than that of the compressor (e.g., main compressor). For example, the auxiliary compressor may include one or more plates that drive movement of the heat transfer fluid via boundary layer effects instead of, for example, an impeller that drives movement of the heat transfer fluid via blades (e.g., impeller blades). The auxiliary compressor may also utilize a direct drive motor and/or a single speed motor. As such, the auxiliary compressor may improve operation of the HVAC&R system having the economizer in a cost-effective manner and without significantly increasing complexity associated with manufacture and/or operation of the HVAC&R system. Additionally, the structure of the auxiliary compressor having the plates (e.g., instead of blades) and the direct drive or single speed motor may limit a footprint (e.g., area, volume) occupied by the auxiliary compressor. For example, the motor may be directly coupled to a shaft (e.g., without usage of additional linkages, such as gears) configured to drive rotation of the plates. Therefore, the compact size of the auxiliary compressor may enable efficient usage of space via the HVAC&R system. In this manner, the auxiliary compressor may pressurize the relatively low flow of the working vapor heat transfer fluid received from the economizer without significantly increasing the cost, footprint, and/or complexity associated with implementation of the auxiliary compressor.

[0025] 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 (e.g., a chiller) 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.

[0026] 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 heat transfer fluid (e.g., 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 (A/D) converter 42, a microprocessor 44, a non-volatile memory 46, and/or an interface board 48. [0027] Some examples of fluids that may be used as heat transfer fluids (e.g., refrigerants) in the vapor compression system 14 are hydrofluorocarbon (HFC) based heat transfer fluids, for example, R-410A, R-407, R-134a, R-1234ze, R1233zd, hydrofluoro olefin (HFO), "natural" heat transfer fluids like ammonia (NH3), R-717, carbon dioxide (CO2), R-744, or hydrocarbon based heat transfer fluids, water vapor, or any other suitable heat transfer fluid. In some embodiments, the vapor compression system 14 may be configured to efficiently utilize heat transfer fluids having a normal boiling point of about 19 degrees Celsius (66 degrees Fahrenheit) at one atmosphere of pressure, also referred to as low pressure heat transfer fluids, versus a medium pressure heat transfer fluid, such as R-134a. As used herein, “normal boiling point” may refer to a boiling point temperature measured at one atmosphere of pressure.

[0028] 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 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.

[0029] The compressor 32 compresses a heat transfer fluid vapor and delivers the vapor to the condenser 34 through a discharge passage. In some embodiments, the compressor 32 may be a centrifugal compressor. The heat transfer fluid vapor delivered by the compressor 32 to the condenser 34 may transfer heat to a cooling fluid (e.g., water or air) in the condenser 34. The heat transfer fluid vapor may condense to a heat transfer fluid liquid in the condenser 34 as a result of thermal heat transfer with the cooling fluid. The liquid heat transfer fluid from the condenser 34 may flow through the expansion device 36 to the evaporator 38. In the illustrated embodiment of FIG. 3, the condenser 34 is water cooled and includes a tube bundle 54 connected to a cooling tower 56, which supplies the cooling fluid to the condenser 34.

[0030] The liquid heat transfer fluid delivered to the evaporator 38 may absorb heat from a conditioning fluid, which may or may not be the same cooling fluid used in the condenser 34. The liquid heat transfer fluid in the evaporator 38 may undergo a phase change from the liquid heat transfer fluid to a heat transfer fluid vapor. As shown in the illustrated embodiment of FIG. 3, the evaporator 38 may include a tube bundle 58 having a supply line 60S and a return line 60R connected to a cooling load 62. The conditioning fluid of the evaporator 38 (e.g., water, ethylene glycol, calcium chloride brine, sodium chloride brine, or any other suitable fluid) enters the evaporator 38 via return line 60R and exits the evaporator 38 via supply line 60S. The evaporator 38 may reduce the temperature of the conditioning fluid in the tube bundle 58 via thermal heat transfer with the heat transfer fluid. The tube bundle 58 in the evaporator 38 can include a plurality of tubes and/or a plurality of tube bundles. In any case, the vapor heat transfer fluid exits the evaporator 38 and returns to the compressor 32 by a suction line to complete the cycle.

[0031] 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, an economizer). 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 heat transfer fluid 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.

[0032] Additionally, the intermediate vessel 70 may provide for further expansion of the liquid heat transfer fluid because of a pressure drop experienced by the liquid heat transfer fluid when entering the intermediate vessel 70 (e.g., due to a rapid increase in volume experienced when entering the intermediate vessel 70). The vapor 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 heat transfer fluid 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.

[0033] It should be appreciated that any of the features described herein may be incorporated with the vapor compression system 14 or any other suitable HVAC&R systems. For example, the present techniques may be incorporated with any HVAC&R system having an economizer, such as the intermediate vessel 70, and a compressor, such as the compressor 32. The discussion below describes the present techniques incorporated with embodiments of the compressor 32 configured as a single stage compressor. However, it should be noted that the systems and methods described herein may be incorporated with other embodiments of the compressor 32 and HVAC&R system 10.

[0034] The present disclosure is directed to a vapor compression system that includes an economizer (e.g., an intermediate vessel) configured to receive heat transfer fluid from a condenser and to separate the heat transfer fluid into liquid heat transfer fluid and vapor heat transfer fluid. The economizer may direct the liquid heat transfer fluid to an evaporator of the vapor compression system to enable the evaporator to place the liquid heat transfer fluid in a heat exchange relationship with a conditioning fluid to cool the conditioning fluid. The vapor compression system may include an auxiliary compressor that may pressurize the vapor heat transfer fluid provided by the economizer, and the auxiliary compressor may have features that more suitably pressurize the relatively low amount of such vapor heat transfer fluid (e.g., as compared to the amount of vapor heat transfer fluid discharged by the condenser and/or the evaporator). For example, the auxiliary compressor may have plates coupled to a shaft and is configured to drive movement of vapor heat transfer fluid via boundary layer effects. A direct drive and/or single speed motor may be coupled to the shaft and may be configured to rotate the shaft and thereby drive rotation of the plates to cause flow and pressurization of the vapor heat transfer fluid. As such, implementation of the auxiliary compressor may be less costly and/or complex than that of other embodiments of a compressor that may include an impeller with blades, a variable speed motor, and/or an indirect drive motor. Additionally or alternatively, a physical footprint (e.g., area, space) occupied by the auxiliary compressor may be limited (e.g., reduced) to enable efficient usage of space by the vapor compression system. Furthermore, the auxiliary compressor may be easily configured, such as to enable a desirable flow and/or pressurization of the heat transfer fluid. For instance, the auxiliary compressor may be modified to adjust a quantity of plates included therein to provide desirable operational characteristics of the auxiliary compressor. As such, the auxiliary compressor may be more easily implemented and/or configured to achieve desirable operation of the vapor compression system.

[0035] With the foregoing in mind, FIG. 5 is a schematic of an embodiment of a vapor compression system 100 that includes a first compressor 101 (e.g., the compressor 32, a main compressor, a primary compressor), the condenser 34, the evaporator 38, and an economizer system 104 having at least one economizer 103 (e g., the intermediate vessel 70). The vapor compression system 100 also includes a second compressor 102 (e.g., an auxiliary compressor, a direct drive compressor, an economizing compressor, a secondary compressor, a multistage compressor, a low flow compressor) fluidly coupled to the economizer 103. The economizer 103 may receive a flow of heat transfer fluid 105 from the condenser 34 and separate (e.g., substantially separate) the heat transfer fluid 105 into liquid heat transfer fluid 107 and vapor heat transfer fluid 109. The second compressor 102 may draw the vapor heat transfer fluid 109 from the economizer 103, compress the vapor heat transfer fluid 109, and discharge the compressed vapor heat transfer fluid 109 to the condenser 34. As an example, the second compressor 102, instead of the first compressor 101, may receive the vapor heat transfer fluid 109 from economizer 103 and direct the vapor heat transfer fluid 109 from the economizer 103 to the condenser 34. The economizer 103 may be configured to discharge the liquid heat transfer fluid 107 to the evaporator 38, for example.

[0036] Additionally, the second compressor 102 may increase the pressure of the vapor heat transfer fluid 109 toward that of vapor heat transfer fluid H l pressurized by the first compressor 101. For example, a first pressure of the vapor heat transfer fluid 111 directed from the first compressor 101 into the condenser 34 (e g., via a first condenser inlet 106) may be similar or substantially the same as a second pressure of the vapor heat transfer fluid 109 directed from the second compressor 102 into the condenser 34 (e.g., via a second condenser inlet 117). The pressurization of the heat transfer fluid flows 109, 111 to approximately the same pressure may block backflow of heat transfer fluid (e.g., through the first condenser inlet 106, through the second condenser inlet 117) that may otherwise occur as a result of a pressure differential between the respective heat transfer fluid flows 109, 111 from the first compressor 101 and from the economizer 103. For example, a desirable flow (e.g., a target flow rate) of heat transfer fluid through the vapor compression system 100 and/or a desirable cooling of the heat transfer fluid provided via the condenser 34 may be achieved.

[0037] An amount of pressurization provided by the second compressor 102 may be less than an amount of pressurization provided by the first compressor 101. By way of example, the pressure of the vapor heat transfer fluid 109 directed from the economizer 103 to the second compressor 102 may be greater than the pressure of the heat transfer fluid 111 directed from the evaporator 38 to the first compressor 101. As such, a first pressure differential between the pressure of the heat transfer fluid 109 received by the second compressor 102 and a corresponding target pressure for pressurization of the heat transfer fluid 109 by the second compressor 102 may be less than a second pressure differential between the pressure of the heat transfer fluid 111 received by the first compressor 101 and a corresponding target pressure for pressurization of the heat transfer fluid 111 by the first compressor 101.

[0038] An embodiment of the second compressor 102 may be different than the embodiment of the first compressor 101. For instance, a design specification and/or operation of the second compressor 102 may be different than that of the first compressor 101. Indeed, as further described herein, the second compressor 102 may be associated with a reduced cost, a reduced size, an increased configurability, and so forth. Thus, the second compressor 102 may facilitate ease of installation, reduce cost of manufacture, provide desirable operation, and so forth associated with the vapor compression system 100.

[0039] FIG. 6 is a schematic of an embodiment of the vapor compression system 100 that includes the second compressor 102. The second compressor 102 may include a boundary layer compressor (e.g., a cohesion-type compressor, a bladeless compressor, a plate compressor, a low flow compressor) that includes a shaft 165 and one or more plates 122 (e.g., one plate, two plates, three or more plates, planar plates, disks, circumferential plates, circular plates) coupled to the shaft 165. Each plate 122 may extend about (e.g., completely about) a circumference of the shaft 165. That is, each plate 122 may surround and/or encircle the shaft 165. However, as described herein, other types of compressors may be incorporated with the vapor compression system 100 as the second compressor 102. The shaft 165 may be coupled to a motor 124, which may be configured to rotate the shaft 165 to drive rotation of the plates 122. In some embodiments, the shaft 165 may form a portion of the motor 124 (e.g., the shaft 165 may be a shaft of the motor 124). Rotation of the plates 122 may cause pressurization of heat transfer fluid 109 received from the economizer 103. As an example, the second compressor 102 may include a compressor inlet 126 configured to receive the vapor heat transfer 109 fluid from the economizer 103, and each plate 122 may receive the vapor heat transfer fluid 109 via the compressor inlet 126. Rotation of the plates 122 may drive the vapor heat transfer fluid 109 radially toward a compressor outlet 128, which may discharge the vapor heat transfer fluid 109 from the second compressor 102 toward the condenser 34 (e.g., via the second condenser inlet 117). A cross-sectional area of the flow path of the vapor heat transfer fluid 109 through the second compressor 102 via rotation of the plates 122 may decrease from the compressor inlet 126 to the compressor outlet 128 in order to enable pressurization of the vapor heat transfer fluid 109. For instance, a size of the compressor outlet 128 may be less than a size of the compressor inlet 126. For clarity, as used herein, a “low flow compressor” may be a compressor (e.g., the second compressor 102) that includes one or more of the plates 122 (e.g., in lieu of blades, such as impeller blades) and is configured to drive movement of heat transfer fluid via boundary layer effects induced by rotation of the one or more plates 122. That is, the low flow compressor is configured to circulate fluid through a fluid loop using boundary layer effects induced by the one or more plates 122 instead of, for example, an impeller that drives movement of the heat transfer fluid via blades (e.g., impeller blades).

[0040] In some embodiments, each plate 122 may utilize boundary layer effects, instead of blades, to drive flow of the vapor heat transfer fluid 109 from the compressor inlet 126 toward the compressor outlet 128. Indeed, the vapor heat transfer fluid 109 may flow along a first direction 130 (e.g., an intake direction) into the second compressor 102 and onto respective surfaces 132 (e.g., opposing surfaces) of the plates 122. During rotation of the plates 122, the surfaces 132 may cause the flow of the vapor heat transfer fluid 109 to adjust from the first direction 130 to a second direction 134 (e.g., a discharge direction), which may be crosswise to the first direction 130, toward the compressor outlet 128. In some embodiments, each plate 122 may have a generally flat geometry (e g., planar geometry). For example, in some embodiments, a majority of the surfaces 132 of the plates 122 (e.g., 60 percent of a surface area of the surfaces 132, 70 percent of a surface area of the surfaces 132, 80 percent of a surface area of the surfaces 132, 90 percent of a surface area of the surfaces 132, 100 percent of a surface area of the surfaces 132) may each include a substantially flat or planar geometry. Additionally or alternatively, the surface 132 of each plate 122 may have a low coefficient of friction (e.g., a low surface roughness) to increase effectiveness of the boundary layer effect to drive flow of the vapor heat transfer fluid 109.

[0041] In certain embodiments, at least one of the plates 122 may include additional features, such as surface formations (e.g., cuts, punches, ribs, blades, ridges, a surface treatment) and/or attachments, to reduce vibration of the second compressor 102 caused by rotation of the plates 122 and therefore increase stability of the second compressor 102. Furthermore, in embodiments in which the second compressor 102 includes multiples plates 122, the plates 122 may be spaced apart from one another (e.g., along a rotational axis of the shaft 165) to form gaps 135 having suitable sizes to enable each plate 122 to receive the vapor heat transfer fluid 109 and to drive flow of the vapor heat transfer fluid 109 toward the compressor outlet 128. For example, the gaps 135 between the plates 122 may be sized based on a viscosity of vapor heat transfer fluid 109 received by the second compressor 102. In some embodiments, a dimension of the gap 135 between each of the plates 122 may be substantially the same. In other embodiments, a dimension of a corresponding gap 135 between a set of the plates 122 may be different than (e.g., greater than, less that) a dimension of a corresponding gap 135 between another set of plates 122. In any case, such features of the second compressor 102 may enable sufficient pressurization of the heat transfer fluid 109received by the second compressor 102 from the economizer 103 (e.g., a relatively low flow of heat transfer fluid 109 as compared to the flow of heat transfer fluid 105 directed from the condenser 34 to the economizer 103 and/or directed from the evaporator 38 to the first compressor 101).

[0042] Additionally, the vapor compression system 100 may include a control system 136 (e.g., the control panel 40 configured to operate the first compressor 101, a control system separate from the control panel 40), which may be an automation controller and/or an electronic controller, configured to operate the second compressor 102. The control system 136 may include a memory 138 and processing circuitry 140. The memory 138 may include volatile memory, such as random-access memory (RAM), and/or non-volatile memory, such as read-only memory (ROM), optical drives, hard disc drives, solid-state drives, or any other non-transitory computer-readable medium storing instructions that, when executed, control operation of the second compressor 102. The processing circuitry 140 may be configured to execute such instructions stored in the memory 138. As an example, the processing circuitry 140 may include one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs), one or more general purpose processors, or any combination thereof.

[0043] In some embodiments, the motor 124 may be a direct drive motor that may be directly coupled to the shaft 165 (e.g., without usage of additional linkages and/or a transmission, such as gears) and may therefore be configured to directly drive rotation of the shaft 165. In this way, fewer components may be utilized to enable the motor 124 to drive operation of the second compressor 102. The motor 124 may additionally or alternatively be a single speed drive (e.g., a single speed motor). Thus, the control system 136 may operate the motor 124 at a fixed speed and reduce complexity associated with operation of the second compressor 102. For example, because the motor 124 may be a single speed drive, the control system 136 may be configured to operate the motor 124 without use of a variable speed drive (VSD). That is, the control system 136 may send signals (e.g., control signals, instructions, electrical current) to transition the motor 124 between an operational state or configuration (e.g., in which the motor 124 may drive rotation of the shaft 165 at a fixed speed or target speed) and an idle or non-operational state or configuration (e.g., a deactivated state in which the motor 124 does not drive rotation of the shaft 165). In certain embodiments, the speed at which the motor 124 operates the second compressor 102 may be lower than the speed at which the motor 50 operates the first compressor 101. As such, costs and/or energy consumption associated with manufacture and operation of the second compressor 102 may be substantially less than that associated with manufacture and operation of the first compressor 101.

[0044] Furthermore, costs and/or complexity associated with manufacture of the second compressor 102 may be less than that of the first compressor 101. By way of example, the shaft 165 and the plates 122 may be less costly and/or less complex than various components, such as an impeller, a diffuser passage, a bearing, a shroud, and so forth, of the first compressor 101. As a result, the design of the second compressor 102 may improve performance (e.g., an efficiency) of the vapor compression system 100 without excessively increasing costs and/or complexity associated with the manufacture and/or operation of the vapor compression system 100.

[0045] Further still, the second compressor 102 may be readily adjustable. For instance, a quantity of plates 122 implemented in the second compressor 102 may be changed to enable the second compressor 102 to achieve a desirable operation (e.g., to achieve desired operational characteristics of the second compressor 102). As an example, additional plates 122 may be implemented to adjust (e.g., increase, decrease) a magnitude by which the second compressor 102 pressurizes heat transfer fluid 109 during operation, to adjust a magnitude of a flow rate at which the second compressor 102 discharges heat transfer fluid 109 during operation, or to adjust other suitable operational characteristics of the second compressor 102. As another example, plates 122 may be removed from the second compressor to reduce pressurization and/or flow rate of the heat transfer fluid 109 directed through the second compressor 102. The configurability of the second compressor 102 may facilitate implementation of the second compressor 102 in various different vapor compression systems 100.

[0046] FIG. 7 is a schematic of an embodiment of the vapor compression system 100 that includes a first economizer 160 (e.g., the economizer 103) and a second economizer 162. In some embodiments, the first and second economizers 160, 162 may form a portion of or all of the economizer system 104. The vapor compression system 100 may also include a second compressor 164 (e.g., an auxiliary compressor, a direct drive an economizing compressor, a secondary compressor, a multistage compressor, an embodiment of the second compressor 102, a low flow compressor) configured to receive heat transfer fluid from the first and second economizers 160, 162.

[0047] For example, the first economizer 160 may receive heat transfer fluid 105 from the condenser 34 and separate the heat transfer fluid into liquid heat transfer fluid 107 (e.g., substantially liquid heat transfer fluid) and vapor heat transfer fluid 109 (e.g., substantially vapor heat transfer fluid). The first economizer 160 may direct the vapor heat transfer fluid 109 to the second compressor 164 for pressurization and discharge back to the condenser 34, and the first economizer 160 may direct the liquid heat transfer fluid 107 to the second economizer 162. The second economizer 162 may reduce a pressure of the liquid heat transfer fluid 107 received from the first economizer 160, thereby vaporizing a portion of the heat transfer fluid 107 and separating the heat transfer fluid 107 into liquid heat transfer fluid 1 1 (e.g., substantially liquid heat transfer fluid) and vapor heat transfer fluid 173 (e.g., substantially vapor heat transfer fluid) within the second economizer 162. The second economizer 162 may direct the liquid heat transfer fluid 171 to the evaporator 38 and the vapor heat transfer fluid 173 to the second compressor 164 for pressurization and discharge to the condenser 34. By further reducing the pressure of the heat transfer fluid 107, the second economizer 162 may increase cooling of the heat transfer fluid 107 prior to discharge to the evaporator 38, thereby increasing an amount of cooling provided by the evaporator 38 to the conditioning fluid.

[0048] As discussed above, the second compressor 164 may include the shaft 165, which may be coupled to the motor 124. The second compressor 164 may include a first stage 167 having a first set of plates 166 coupled to the shaft 165 and a second stage 169 having a second set of plates 168 coupled to the shaft 165. Each plate of the sets of plates 166, 168 may have a similar design as that of the plates 122 of the second compressor 102. Indeed, each of the plates 122 of the second compressor 164 may also be configured to drive flow of the heat transfer fluid (e.g., vapor heat transfer fluid) received from the economizers 160, 162 via boundary layer effects. The sets of plates 166, 168 may be in a series flow arrangement 175 within the second compressor 164 to enable each stage 167, 169 to provide additional pressurization of the heat transfer fluid. For example, the first stage 167 may receive heat transfer fluid 173 via a first compressor inlet 170, and the first set of plates 166 at the first stage 167 may be configured to receive heat transfer fluid 173, pressurize the heat transfer fluid 173, and direct the pressurized heat transfer fluid 173 to the second stage 169 via an intermediate inlet 172. At the second stage 169, the second set of plates 168 may further pressurize the heat transfer fluid 173 and discharge the heat transfer fluid 173 to the condenser 34 via a compressor outlet 174.

[00491 In some embodiments, the second economizer 162 may direct vapor heat transfer fluid 173 into the first stage 167 of the second compressor 164 via the first compressor inlet 170 for compression via the first set of plates 166. The first economizer 160 may direct vapor heat transfer fluid 109 into the second stage 169 of the second compressor 164 via a second compressor inlet 176 that directs the vapor heat transfer fluid 109 to the second set of plates 168 and bypass the first set of plates 166. That is, the vapor heat transfer fluid 173 directed by the second economizer 162 may undergo pressurization at both the first stage 167 and the second stage 169 via the first set of plates 166 and the second set of plates 168. However, the vapor heat transfer fluid 109 directed by the first economizer 160 may undergo pressurization at the second stage 169 via the second set of plates 168 and not at the first stage 167 via the first set of plates 166. By way of example, the vapor heat transfer fluid 109 directed by the first economizer 160 may be at a higher pressure than the vapor heat transfer fluid 173 directed by the second economizer 162. For this reason, the vapor heat transfer fluid 109 directed by the first economizer 160 may undergo relatively less pressurization to achieve a desirable pressure for flow into the condenser 34, and the vapor heat transfer fluid 173 received from the second economizer 162 may undergo relatively more pressurization to achieve the desirable pressure level for flow into the condenser 34. Therefore, the vapor heat transfer fluid 109 directed by the first economizer 160 may be pressurized via the second stage 169 and directed to the condenser 34, and the vapor heat transfer fluid 173 directed by the second economizer 162 may be pressurized via the first stage 167, further pressurized via the second stage 169, and then directed to the condenser 34. The heat transfer fluids 109, 173 are thus output by the second compressor 164 to the condenser 34 as a heat transfer fluid flow 180.

[0050] FIG. 8 is a schematic of an embodiment of the vapor compression system 100 that includes the first economizer 160, the second economizer 162, and the second compressor 164 (e.g., a low flow compressor) that includes the first stage 167 and the second stage 169. Tn the illustrated embodiment, the first economizer 160 and the second economizer 162 are a part of (e.g., disposed within) an economizer enclosure 200. For example, the first economizer 160 and the second economizer 162 may be separate chambers, compartments, or volumes within the economizer enclosure 200 and may be separated from one another within the economizer enclosure 200 via a partition, a wall, a divider, a plate, and the like. Thus, a single economizer enclosure 200 may include multiple economizers 160, 162.

[0051] Operation of the economizers 160, 162 may be similar to that as described herein. That is, the first economizer 160 may receive heat transfer fluid 105 from the condenser 34, separate the heat transfer fluid 105 into liquid heat transfer fluid 107 and vapor heat transfer fluid 109, direct the vapor heat transfer fluid 109 to the second stage 169 of the second compressor 164, and direct the liquid heat transfer fluid 107 to the second economizer 162. The second economizer 162 may reduce a pressure of the liquid heat transfer fluid 107 received from the first economizer 160 to vaporize a portion of the liquid heat transfer fluid 107 to produce liquid heat transfer fluid 171 and vapor heat transfer fluid 173, direct the liquid heat transfer fluid 171 to the evaporator 38, and direct the vapor heat transfer fluid 173 to the first stage 167 of the second compressor 164.

[0052] The second compressor 164 may be mounted (e.g., directly mounted), secured (e.g., directly secured), or coupled (e.g., directly coupled) to the economizer enclosure 200. For example, the economizer enclosure 200 may include an interface 201, such as a mounting surface, and the second compressor 164 may be attached to the interface 201, such as via a fastener, an adhesive, a weld, an interference fit, another suitable feature, or any combination thereof. Thus, the second compressor 164 may be secured within the vapor compression system 100 without utilizing a securement or mounting system that is separate from the economizer enclosure 200. That is, the economizer enclosure 200 may be configured to support (e.g., fully support) the second compressor 164 and brace the second compressor 164 (e.g., support a weight of the second compressor 164), for example.

[0053] In additional or alternative embodiments, the second compressor 164 may be mounted to a different component of the vapor compression system 100, such as an individual one of the economizers 160, 162 (e.g., separate enclosures of the economizers 160, 162), the condenser 34 (e.g., a condenser shell), the evaporator 38 (e.g., an evaporator shell), and/or the first compressor 101 (e.g., a compressor skid). As a result, the second compressor 164 may be mounted to existing vapor compression equipment of the vapor compression system 100 to reduce a manufacturing and/or installation cost or complexity, as well as limit a physical footprint occupied by the vapor compression system 100, such as in comparison to a vapor compression system 100 that may utilize a separate support or structure dedicated to securement of the second compressor 164 within the vapor compression system 100.

[0054] FIG. 9 is a schematic of an embodiment of the vapor compression system 100 that includes the first economizer 160, the second economizer 162, and a third economizer 220. For example, the economizers 160, 162, 220 may be chambers of a common economizer enclosure and/or separate economizers that may have their own, respective enclosures. In some embodiments, the first, second, and third economizers 160, 162, 220 may form a portion of or all of the economizer system 104. Additionally, the vapor compression system 100 includes the second compressor 164 (e.g., a low flow compressor), which may include the first stage 167 having the first set of plates 166, the second stage 169 having the second set of plates 168, and a third stage 222 having a third set of plates 224. Each of the sets of plates 166, 168, 224 may be coupled to the shaft 165.

[0055] The first economizer 160 may receive heat transfer fluid 105 from the condenser 34, reduce the pressure of the heat transfer fluid 105 to separate the heat transfer fluid into liquid heat transfer fluid 107 and vapor heat transfer fluid 109, direct the vapor heat transfer fluid 109 to the third stage 222 of the second compressor 164 via a third compressor inlet 226, and direct the liquid heat transfer fluid 107 to the second economizer 162. The second economizer 162 may reduce a pressure of the liquid heat transfer fluid 107 received from the first economizer 160 to vaporize a portion of the liquid heat transfer fluid 107 to produce liquid heat transfer fluid 171 and vapor heat transfer fluid 173, direct the liquid heat transfer fluid 171 to the third economizer 220, and direct the vapor heat transfer fluid 173 to the second stage 169 of the second compressor 164 via the second compressor inlet 176. The third economizer 220 may reduce a pressure of the liquid heat transfer fluid 171 received from the second economizer 162 to vaporize a portion of the liquid heat transfer fluid 171 to produce liquid heat transfer fluid 223 and vapor heat transfer fluid 225, direct the liquid heat transfer fluid 223 to the evaporator 38, and direct the vapor heat transfer fluid 225 to the first stage 167 of the second compressor 164 via the first compressor inlet 170.

[0056] The first stage 167 of the second compressor 164 may receive the vapor heat transfer fluid 225 from the third economizer 220, and the first set of plates 166 may pressurize the vapor heat transfer fluid 225 and direct the pressurized vapor heat transfer fluid 225 to the second stage 169 via the intermediate inlet 172. The second stage 169 may receive the vapor heat transfer fluid from the first stage 167 and/or from the second economizer 162, and the second set of plates 168 may pressurize the vapor heat transfer fluid and direct the pressurized vapor heat transfer fluid to the third stage 222 via an additional intermediate inlet 228. The third stage 222 may receive the vapor heat transfer fluid from the second stage 169 and/or from the first economizer 160, and the third set of plates 224 may pressurize the vapor heat transfer fluid and discharge the pressurized vapor heat transfer fluid 180 to the condenser 34 via the compressor outlet 174.

[0057] In additional or alternative embodiments, the second compressor 164 may include any suitable quantity of stages 167, 169, 222 (e.g., the same quantity of stages as the quantity of economizers, a different quantity of stages as the quantity of economizers). The sets of plates 166, 168, 224 associated with the respective stages 167, 169, 222 may include any suitable quantity of plates, such as the same or a different quantity of plates relative to one another. Furthermore, although the stages 167, 169, 222 of the second compressor 164 described herein are in a series flow arrangement, the stages 167, 169, 222 may be in a parallel flow arrangement in an additional or alternative embodiment. For example, each set of plates 166, 168, 224 may be coupled to a different shaft, and may each, for instance, discharge pressurized heat transfer fluid directly to the condenser 34.

[0058] Although the present techniques are described as implemented via usage of boundary layer type auxiliary compressors to pressurize the relatively low flow of heat transfer fluid directed by an economizer, it should be appreciated that other types of low flow compressors may be utilized in other embodiments. For example, the auxiliary compressor may include any other suitable type of compressor (e.g., low flow compressor, low flow coefficient compressor), such as a rotary compressor, a reciprocating compressor, a scroll compressor, a centrifugal compressor, an oil-free compressor, a compact compressor, and/or any other suitable type of compressor configured to pressurize a low flow of heat transfer fluid. Indeed, any suitable type of auxiliary compressor configured for reduced flow and/or capacity (e.g., relative to a primary compressor of the vapor compression system). Such types of compressors may be driven by a direct drive motor, in some embodiments. For this reason, the auxiliary compressor may be associated with a lower cost, a limited complexity, a smaller physical footprint, a lower energy consumption, and so forth. Moreover, the auxiliary compressors of any of the aforementioned types may have a multi-stage configuration to enable receipt and pressurization of respective heat transfer fluid flows from different economizers.

[0059] While only certain features and embodiments of the present disclosure 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 resequenced according to alternative embodiments. It is, therefore, to be noted that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the present 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 present disclosure, or those unrelated to enabling the claimed embodiments). 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.

[0060] The techniques presented and claimed herein are referenced and applied to material objects and concrete examples of a practical nature that demonstrably improve the present technical field and, as such, are not abstract, intangible or purely theoretical. Further, if any claims appended to the end of this specification contain one or more elements designated as “means for [performing [a function]...” or “step for [performing [a function]...”, it is intended that such elements are to be interpreted under 35 U.S.C. 112(f). However, for any claims containing elements designated in any other manner, it is intended that such elements are not to be interpreted under 35 U.S.C. 112(f).