Compressor system for HVACR system

Abstract

The present disclosure relates to a method for heating, ventilation, air conditioning and / or refrigeration (HVACamp; r) system (100), the HVACamp; the R system includes an economizer (103) configured to receive the heat transfer fluid (105) from the condenser (34). The economizer (103) is configured to separate the heat transfer fluid (105) into a liquid heat transfer fluid (107) and a vapor heat transfer fluid (109). The HVACamp; the R system (100) includes a low flow compressor (102) configured to receive the vapor heat transfer fluid (109) from the economizer (103), pressurize the vapor heat transfer fluid (109), and direct the vapor heat transfer fluid (109) to the condenser (34).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 353,403, filed on June 17, 2022, entitled “COMPRESSOR SYSTEM FOR HVAC&R SYSTEM,” which is hereby incorporated by reference in its entirety for all purposes. Background Art

[0003] This section is intended to introduce the reader to various aspects of the technology that may be related to various aspects of the present disclosure described below. It is believed that this discussion helps to provide the reader with background information to promote a better understanding of various aspects of the present disclosure. Therefore, it should be understood that these statements should be read in this light, rather than as an admission of the prior art.

[0004] A chiller system or vapor compression system utilizes a working fluid (e.g., a refrigerant) that changes the phase between vapor, liquid, and a combination thereof in response to different temperatures and pressures within the components exposed to the chiller system. The chiller system can place the working fluid in a heat exchange relationship with a conditioning fluid (e.g., water), and can deliver the conditioning fluid to a conditioning device and / or a regulated environment served by the chiller system. In some embodiments, the chiller system may include an economizer configured to improve the 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 the pressure of the working fluid to further cool the working fluid and separate the working fluid into a liquid-phase working fluid and a gas-phase working fluid. The economizer may direct the liquid-phase working fluid to a second heat exchanger (e.g., an evaporator), which is configured to place the working fluid in a heat exchange relationship with the conditioning fluid. The economizer may direct the gas-phase working fluid to a compressor for pressurization. Unfortunately, existing chiller systems including economizers may be costly and / or may be inefficient in operation. Summary of the invention

[0005] The following describes an overview of certain embodiments disclosed herein. It should be understood that these aspects presented are only intended to provide the reader with a brief summary of certain embodiments, and these aspects are not intended to limit the scope of the present disclosure. In fact, the present disclosure may encompass various aspects that may not be described below.

[0006] 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 a liquid heat transfer fluid and a 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.

[0007] 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 a liquid heat transfer fluid and a 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 the vapor heat transfer fluid to flow through the compressor via a boundary layer effect applied by a surface of the plate and to pressurize the vapor heat transfer fluid to produce a 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.

[0008] 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 a liquid heat transfer fluid and a 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 a boundary layer effect imposed on the vapor heat transfer fluid by a surface of the plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Various aspects of the present disclosure may be better understood after reading the following detailed description and referring to the drawings, in which:

[0010] Figure 1 is a perspective view of a building in which an embodiment of a heating, ventilation, air conditioning and / or refrigeration (HVAC&R) system may be utilized in a commercial environment according to one aspect of the present disclosure;

[0011] Figure 2 is a perspective view of an embodiment of a vapor compression system according to one aspect of the present disclosure;

[0012] Figure 3 According to one aspect of the present disclosure Figure 2 A schematic diagram of an embodiment of a vapor compression system;

[0013] Figure 4 According to one aspect of the present disclosure Figure 2A schematic diagram of an embodiment of a vapor compression system;

[0014] Figure 5 According to one aspect of the present disclosure Figure 2 A schematic diagram of an embodiment of a vapor compression system;

[0015] Figure 6 is a schematic diagram of an embodiment of a vapor compression system according to one aspect of the present disclosure, the vapor compression system including an economizer and a compressor configured to receive a heat transfer fluid from the economizer;

[0016] Figure 7 is a schematic diagram of an embodiment of a vapor compression system according to one aspect of the present disclosure, the vapor compression system including a plurality of economizers and a compressor configured to receive a heat transfer fluid from the economizers;

[0017] Figure 8 is a schematic diagram of an embodiment of a vapor compression system according to one aspect of the present disclosure, the vapor compression system including a plurality of economizers and a compressor configured to receive a heat transfer fluid from the economizers; and

[0018] Fig. 9 is a schematic diagram of an embodiment of a vapor compression system according to one aspect of the present disclosure, the vapor compression system including a plurality of economizers and a compressor configured to receive a heat transfer fluid from the economizers. DETAILED DESCRIPTION

[0019] One or more specific embodiments will be described below. In order to provide a concise description of these embodiments, not all features of the actual implementation scheme are described in the specification. It should be understood that in the development of any such actual implementation, as in any engineering or design project, a large number of implementation-specific decisions must be made to achieve the developer's specific goals, such as complying with system-related and business-related constraints, which may vary from implementation to implementation. In addition, it should be understood that such development work may be complex and time-consuming, but is no more than a routine task of design, manufacturing, and production for ordinary technicians who benefit from this disclosure.

[0020] 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 in addition to 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 are further incorporated into the recited features.

[0021] As used herein, the terms "approximately," "substantially," "substantially," and the like are intended to convey that the value of the property being described may be within a relatively small range of that property value, as understood by one skilled in the art. 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, "substantially perpendicular" to another feature, and the like, this is intended to convey that the given feature is within + / -5%, within + / -4%, within + / -3%, within + / -2%, within + / -1%, or even closer of the described property, such as being parallel to another feature, being perpendicular to another feature, and the like. Mathematical terms, such as "parallel" and "perpendicular," should not be strictly interpreted in a strict mathematical sense, but rather should be interpreted as one of ordinary skill in the art would interpret such terms. For example, one of ordinary skill in the art will understand that two lines that are generally parallel to each other are largely parallel, but may have slight deviations from being completely parallel.

[0022] 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., a vapor compression loop). The vapor compression system may include a compressor (e.g., a main compressor) configured to pressurize a heat transfer fluid (e.g., a 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 the pressure of the heat transfer fluid, thereby further cooling the heat transfer fluid. The cooled heat transfer fluid may be directed from the expansion device to an evaporator, in which the heat transfer fluid may be in heat exchange relationship with a conditioning fluid to cool the conditioning fluid. Subsequently, the compressor may receive the heat transfer fluid from the evaporator for pressurization, thereby restarting the vapor compression cycle.

[0023] In some embodiments, the vapor compression system may include an economizer configured to receive a heat transfer fluid from a condenser. The economizer may be configured to reduce the pressure of the heat transfer fluid and separate the heat transfer fluid into a liquid heat transfer fluid (e.g., a first fractional percentage) and a vapor heat transfer fluid (e.g., a first fractional percentage, the second fractional percentage being equal to 1 minus the first fractional percentage). The economizer may guide the liquid heat transfer fluid to the evaporator so that the evaporator can heat exchange the liquid heat transfer fluid with the conditioning fluid. The vapor heat transfer fluid may be guided from the economizer to the condenser and pass through the compressor. However, because the pressure of the heat transfer fluid (e.g., vapor heat transfer fluid) in the condenser may be higher than the pressure of the heat transfer fluid (e.g., vapor heat transfer fluid) in the economizer, in some cases, the heat transfer fluid guided from the economizer may not easily flow to or flow through (e.g., flow directly to, flow directly through) the condenser. That is, the pressure difference between the heat transfer fluid in the condenser and the heat transfer fluid in the economizer may prevent the natural flow of the heat transfer fluid from the economizer directly to the condenser (e.g., the heat transfer fluid is not pressurized at the economizer). In addition, the vapor heat transfer fluid directed from the economizer can be combined with the heat transfer fluid pressurized by the compressor, but the corresponding heat transfer fluid streams can be at different pressures. The pressure difference between the heat transfer fluid streams can disturb the flow of the heat transfer fluid to and / or through the condenser. For example, the pressure difference may cause the heat transfer fluid to flow back in a direction associated with a lower heat transfer fluid pressure (e.g., toward the compressor, toward the economizer), rather than flowing to and / or flowing through the condenser.

[0024] Therefore, it is now recognized that there is a need for improvements to HVAC&R systems having one or more economizers, such as pressurizing a vapor heat transfer fluid that can be directed from an economizer and can have a relatively low flow rate (e.g., pressure, mass flow rate) compared to a heat transfer fluid directed from a condenser and / or from an evaporator. Therefore, the present disclosure relates to incorporating an additional auxiliary compressor that is configured to receive a vapor heat transfer fluid from an economizer, pressurize the vapor heat transfer fluid, and direct the pressurized vapor heat transfer fluid toward a condenser. The auxiliary compressor can pressurize the vapor heat transfer fluid toward the pressure of the heat transfer fluid pressurized by a compressor (e.g., a main compressor). Therefore, the auxiliary compressor can reduce the pressure difference between the corresponding heat transfer fluid flows directed to and / or through the condenser and / or reduce the flow of the heat transfer fluid through the compressor (e.g., a main compressor), thereby improving the efficiency of the HVAC&R system, such as by reducing the total power used to cool or heat the heat transfer fluid at the evaporator or condenser, respectively.

[0025] The cost and / or complexity associated with the manufacture and / or operation of the auxiliary compressor can be less than the cost and / or complexity of the compressor (e.g., the main compressor). For example, the auxiliary compressor may include one or more plates that drive the movement of the heat transfer fluid via a boundary layer effect, rather than, for example, an impeller that drives the movement of the heat transfer fluid via blades (e.g., impeller blades). The auxiliary compressor can also utilize a direct drive motor and / or a single-speed motor. Therefore, the auxiliary compressor can improve the operation of the HVAC&R system with an economizer in a cost-effective manner, and will not significantly increase the complexity associated with the manufacture and / or operation of the HVAC&R system. In addition, the structure of the auxiliary compressor with a plate (e.g., instead of a blade) and a direct drive or single-speed motor may limit the occupied space (e.g., area, volume) occupied by the auxiliary compressor. For example, the motor can be directly connected to a shaft configured to drive the plate to rotate (e.g., without using an additional linkage, such as a gear). Therefore, the compact size of the auxiliary compressor can achieve efficient use of space via the HVAC&R system. In this manner, the auxiliary compressor may pressurize a relatively low flow rate of working vapor heat transfer fluid received from the economizer without significantly increasing the cost, footprint, and / or complexity associated with the implementation of the auxiliary compressor.

[0026] Turning now to the accompanying drawings, Figure 1 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 environment. The HVAC&R system 10 can include a vapor compression system 14 (e.g., a chiller) that supplies a cooling liquid that can be used to cool the building 12. The HVAC&R system 10 can also include a boiler 16 for supplying warm liquid to heat the building 12 and an air distribution system that circulates air through the building 12. The air distribution system can also include air return ducts 18, air supply ducts 20, and / or air handlers 22. In some embodiments, the air handler 22 can include a heat exchanger that is connected to the boiler 16 and the vapor compression system 14 via ducts 24. Depending on the operating mode of the HVAC&R system 10, the heat exchanger in the air handler 22 can receive heated liquid from the boiler 16 or cooled liquid from the vapor compression system 14. The HVAC&R system 10 is shown with separate air handlers on each floor of the 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 floors.

[0027] Figure 2 and Figure 3is an embodiment of a vapor compression system 14 that may 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 that begins with a compressor 32. The circuit may also include a condenser 34, one or more expansion valves or devices 36, and a liquid cooler or evaporator 38. The vapor compression system 14 may further include a control panel 40 having an analog-to-digital (A / D) converter 42, a microprocessor 44, a non-volatile memory 46, and / or an interface board 48.

[0028] Some examples of fluids that can be used as heat transfer fluids (e.g., refrigerants) in the vapor compression system 14 are hydrofluorocarbon (HFC)-based heat transfer fluids (e.g., R-410A, R-407, R-134a, R-1234ze, R1233zd, hydrofluoroolefins (HFO)), "natural" heat transfer fluids (such as 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 can be configured to effectively utilize a heat transfer fluid having a normal boiling point of about 19 degrees Celsius (66 degrees Fahrenheit) at one atmosphere of pressure, also referred to as a low-pressure heat transfer fluid relative to a medium-pressure heat transfer fluid (such as R-134a). As used herein, "normal boiling point" can refer to the boiling point temperature measured at one atmosphere of pressure.

[0029] In some embodiments, the vapor compression system 14 may use one or more of 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 the variable speed drive (VSD) 52. The VSD 52 receives AC power having a specific fixed line voltage and a fixed line frequency from an alternating current (AC) power source and provides power having a variable voltage and frequency to the motor 50. In other embodiments, the motor 50 may be powered directly by an AC or direct current (DC) power source. The motor 50 may include any type of motor that may be powered by a VSD or directly by 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.

[0030] The compressor 32 compresses the 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 to the condenser 34 by the compressor 32 may transfer heat to a cooling fluid (e.g., water or air) in the condenser 34. As a result of the heat transfer with the cooling fluid, the heat transfer fluid vapor may condense into a heat transfer fluid liquid in the condenser 34. The liquid heat transfer fluid from the condenser 34 may flow to the evaporator 38 through the expansion device 36. Figure 3In the illustrated embodiment, the condenser 34 is water cooled and includes a tube bundle 54 connected to a cooling tower 56 that supplies cooling fluid to the condenser 34 .

[0031] 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 a liquid heat transfer fluid to a heat transfer fluid vapor. Figure 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. A conditioning fluid (e.g., water, ethylene glycol, calcium chloride brine, sodium chloride brine, or any other suitable fluid) for the evaporator 38 enters the evaporator 38 via the return line 60R and exits the evaporator 38 via the supply line 60S. The evaporator 38 may reduce the temperature of the conditioning fluid in the tube bundle 58 via heat transfer with the heat transfer fluid. The tube bundle 58 in the evaporator 38 may 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 is returned to the compressor 32 through the suction line to complete the cycle.

[0032] Figure 4 is a schematic diagram of vapor compression system 14 in which intermediate loop 64 is incorporated between condenser 34 and expansion device 36. Intermediate loop 64 may have an inlet line 68 that is directly fluidly connected to condenser 34. In other embodiments, inlet line 68 may be indirectly fluidly coupled to condenser 34. Figure 4 In the illustrated embodiment, 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." Figure 4 In the illustrated embodiment of , the intermediate vessel 70 is used as a flash tank, and the first expansion device 66 is configured to reduce (e.g., expand) the pressure of the liquid heat transfer fluid received from the condenser 34. During the expansion process, a portion of the liquid may evaporate, and thus the intermediate vessel 70 may be used to separate the vapor from the liquid received from the first expansion device 66.

[0033] In addition, the intermediate container 70 can provide further expansion of the liquid heat transfer fluid due to the pressure drop experienced by the liquid heat transfer fluid when entering the intermediate container 70 (e.g., due to the rapid increase in volume experienced when entering the intermediate container 70). The vapor in the intermediate container 70 can be sucked in by the compressor 32 through the suction line 74 of the compressor 32. In other embodiments, the vapor in the intermediate container can be drawn into an intermediate stage (e.g., a non-suction stage) of the compressor 32. Due to the expansion in the expansion device 66 and / or the intermediate container 70, the enthalpy of the liquid collected in the intermediate container 70 can be lower than the enthalpy of the liquid heat transfer fluid leaving the condenser 34. The liquid from the intermediate container 70 can then flow in line 72 through the second expansion device 36 to the evaporator 38.

[0034] It should be understood that any of the features described herein can be combined with the vapor compression system 14 or any other suitable HVAC&R system. For example, the present technology can be combined with any HVAC&R system having an economizer (such as the intermediate container 70) and a compressor (such as the compressor 32). The following discussion describes the present technology in combination with an embodiment of the compressor 32 configured as a single-stage compressor. However, it should be noted that the systems and methods described herein can be combined with other embodiments of the compressor 32 and the HVAC&R system 10.

[0035] The present disclosure relates to a vapor compression system, which includes an economizer (e.g., an intermediate container) configured to receive a heat transfer fluid from a condenser and separate the heat transfer fluid into a liquid heat transfer fluid and a vapor heat transfer fluid. The economizer may guide the liquid heat transfer fluid to the evaporator of the vapor compression system so that the evaporator can make 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 can pressurize the vapor heat transfer fluid provided by the economizer, and the auxiliary compressor may have a feature that is more suitable for pressurizing a relatively small amount of such vapor heat transfer fluid (e.g., compared to the amount of vapor heat transfer fluid discharged by the condenser and / or evaporator). For example, the auxiliary compressor may have a plate coupled to a shaft and is configured to drive the movement of the vapor heat transfer fluid via a boundary layer effect. 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 the rotation of the plate to cause the flow and pressurization of the vapor heat transfer fluid. Therefore, the auxiliary compressor can be implemented at a lower cost and / or with lower complexity than other embodiments of the compressor that may include an impeller with blades, a variable speed motor, and / or an indirect drive motor. Additionally or alternatively, the physical footprint (e.g., area, space) occupied by the auxiliary compressor can be limited (e.g., reduced) to enable efficient use of the space by the vapor compression system. In addition, the auxiliary compressor can be easily configured, such as to enable the heat transfer fluid to achieve a desired flow and / or pressurization. For example, the auxiliary compressor can be modified to adjust the number of plates included therein to provide the desired operating characteristics of the auxiliary compressor. Therefore, the auxiliary compressor can be more easily implemented and / or configured to achieve the desired operation of the vapor compression system.

[0036] Considering the foregoing, Figure 5is a schematic diagram of an embodiment of a vapor compression system 100, which includes a first compressor 101 (e.g., compressor 32, main compressor, main compressor), a condenser 34, an evaporator 38, and an economizer system 104 having at least one economizer 103 (e.g., intermediate container 70). The vapor compression system 100 also includes a second compressor 102 (e.g., auxiliary compressor, direct drive compressor, economizer compressor, auxiliary compressor, multi-stage compressor, low flow compressor) fluidly coupled to the economizer 103. The economizer 103 can receive a heat transfer fluid stream 105 from the condenser 34 and separate (e.g., substantially separate) the heat transfer fluid 105 into a liquid heat transfer fluid 107 and a vapor heat transfer fluid 109. The second compressor 102 can extract 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, second compressor 102, rather than first compressor 101, may receive vapor heat transfer fluid 109 from economizer 103 and direct vapor heat transfer fluid 109 from economizer 103 to condenser 34. For example, economizer 103 may be configured to discharge liquid heat transfer fluid 107 to evaporator 38.

[0037] In addition, the second compressor 102 can increase the pressure of the vapor heat transfer fluid 109 to the pressure of the vapor heat transfer fluid 111 pressurized by the first compressor 101. For example, the first pressure of the vapor heat transfer fluid 111 directed from the first compressor 101 to the condenser 34 (e.g., via the first condenser inlet 106) can be similar or substantially the same as the second pressure of the vapor heat transfer fluid 109 directed from the second compressor 102 to the condenser 34 (e.g., via the second condenser inlet 117). Pressurizing the heat transfer fluid streams 109, 111 to substantially the same pressure can prevent backflow of the heat transfer fluid (e.g., through the first condenser inlet 106, through the second condenser inlet 117), which otherwise may occur due to the pressure difference between the respective heat transfer fluid streams 109, 111 from the first compressor 101 and from the economizer 103. For example, a desired flow rate (e.g., a target flow rate) of the heat transfer fluid through the vapor compression system 100 and / or a desired cooling of the heat transfer fluid provided via the condenser 34 can be achieved.

[0038] The amount of pressurization provided by the second compressor 102 may be less than the amount of pressurization provided by the first compressor 101. For 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. Therefore, a first pressure difference between the pressure of the heat transfer fluid 109 received by the second compressor 102 and a corresponding target pressure for pressurizing the heat transfer fluid 109 by the second compressor 102 may be less than a second pressure difference between the pressure of the heat transfer fluid 111 received by the first compressor 101 and a corresponding target pressure for pressurizing the heat transfer fluid 111 by the first compressor 101.

[0039] Embodiments of the second compressor 102 can differ from embodiments of the first compressor 101. For example, the design specifications and / or operation of the second compressor 102 can differ from the design specifications and / or operation of the first compressor 101. Indeed, as further described herein, the second compressor 102 can be associated with reduced cost, reduced size, increased configurability, etc. Thus, the second compressor 102 can facilitate ease of installation, reduce manufacturing costs, provide desired operations associated with the vapor compression system 100, etc.

[0040] Figure 61 is a schematic diagram of an embodiment of a vapor compression system 100 including a second compressor 102. The second compressor 102 may include a boundary layer compressor (e.g., a cohesive 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, a planar plate, a disk, a circumferential plate, a circular plate) coupled to the shaft 165. Each plate 122 may extend around the circumference of the shaft 165 (e.g., completely around the 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 combined 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 the rotation of the plate 122. In some embodiments, the shaft 165 may form a portion of the motor 124 (e.g., the shaft 165 may be the shaft of the motor 124). The rotation of the plates 122 may cause the pressurization of the 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 fluid 109 from the economizer 103, and each plate 122 may receive the vapor heat transfer fluid 109 via the compressor inlet 126. The rotation of the plates 122 may drive the vapor heat transfer fluid 109 radially toward the 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). The cross-sectional area of ​​the flow path of the vapor heat transfer fluid 109 through the second compressor 102 via the rotation of the plates 122 may decrease from the compressor inlet 126 to the compressor outlet 128 so as to enable the pressurization of the vapor heat transfer fluid 109. For example, the size of the compressor outlet 128 may be smaller than the 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 plates 122 (e.g., in place of blades, such as impeller blades) and is configured to drive movement of a heat transfer fluid via a boundary layer effect caused by rotation of the one or more plates 122. That is, the low-flow compressor is configured to circulate the fluid through the fluid circuit using the boundary layer effect caused by the one or more plates 122, rather than, for example, an impeller that drives movement of the heat transfer fluid via blades (e.g., impeller blades).

[0041] In some embodiments, each plate 122 may utilize a boundary layer effect instead of blades to drive the vapor heat transfer fluid 109 from the compressor inlet 126 to the compressor outlet 128. In practice, the vapor heat transfer fluid 109 may flow into the second compressor 102 along a first direction 130 (e.g., an intake direction) and onto a corresponding surface 132 (e.g., an opposing surface) of the plate 122. During rotation of the plate 122, the surface 132 may adjust the flow of the vapor heat transfer fluid 109 from the first direction 130 to a second direction 134 (e.g., a discharge direction), which may intersect the first direction 130 toward the compressor outlet 128. In some embodiments, each plate 122 may have a generally flat geometry (e.g., a planar geometry). For example, in some embodiments, a majority of the surfaces 132 of the plates 122 (e.g., 60% of the surface area of ​​the surfaces 132, 70% of the surface area of ​​the surfaces 132, 80% of the surface area of ​​the surfaces 132, 90% of the surface area of ​​the surfaces 132, 100% of the 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., low surface roughness) to increase the effectiveness of the boundary layer effect in driving the flow of the vapor heat transfer fluid 109.

[0042] In certain embodiments, at least one of the plates 122 may include additional features, such as surface configurations (e.g., cutouts, punchings, ribs, blades, ridges, surface treatments) and / or attachments to reduce vibrations of the second compressor 102 caused by the rotation of the plates 122 and, thus, increase the stability of the second compressor 102. In addition, in embodiments where the second compressor 102 includes a plurality of plates 122, the plates 122 may be spaced apart from one another (e.g., along the axis of rotation of the shaft 165) to form gaps 135 of suitable size so that each plate 122 can receive the vapor heat transfer fluid 109 and drive the vapor heat transfer fluid 109 toward the compressor outlet 128. For example, the size of the gaps 135 between the plates 122 may be determined based on the viscosity of the vapor heat transfer fluid 109 received by the second compressor 102. In some embodiments, the size of the gaps 135 between each plate 122 may be substantially the same. In other embodiments, the size of the corresponding gaps 135 between one set of plates 122 may be different (e.g., larger, smaller) than the size of the corresponding gaps 135 between another set of plates 122. In any case, these features of the second compressor 102 can enable the heat transfer fluid 109 received by the second compressor 102 from the economizer 103 to be adequately pressurized (e.g., a relatively lower flow of heat transfer fluid 109 compared to the flow of heat transfer fluid 105 directed from the condenser 34 to the economizer 103 and / or from the evaporator 38 to the first compressor 101).

[0043] In addition, the vapor compression system 100 may include a control system 136 (e.g., a control panel 40 configured to operate the first compressor 101, a control system separate from the control panel 40), which may be an automated controller and / or an electronic controller configured to operate the second compressor 102. The control system 136 may include a memory 138 and a processing circuit 140. The memory 138 may include a volatile memory, such as a random access memory (RAM), and / or a non-volatile memory, such as a read-only memory (ROM), an optical drive, a hard drive, a solid-state drive, or any other non-transitory computer-readable medium storing instructions that, when executed, control the operation of the second compressor 102. The processing circuit 140 may be configured to execute such instructions stored in the memory 138. As an example, the processing circuit 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.

[0044] In some embodiments, the motor 124 can be a direct drive motor that can be directly coupled to the shaft 165 (e.g., without using additional connecting rods and / or transmission devices, such as gears), and thus can be configured to directly drive the rotation of the shaft 165. In this way, fewer components can be used to enable the motor 124 to drive the operation of the second compressor 102. The motor 124 can additionally or alternatively be a single-speed drive (e.g., a single-speed motor). Therefore, the control system 136 can operate the motor 124 at a fixed speed and reduce the complexity associated with the operation of the second compressor 102. For example, because the motor 124 can be a single-speed drive, the control system 136 can be configured to operate the motor 124 without using a variable speed drive (VSD). That is, the control system 136 can send a signal (e.g., a control signal, a command, a current) to convert the motor 124 between an operating state or configuration (e.g., where the motor 124 can drive the shaft 165 to rotate at a fixed speed or a target speed) and an idle or non-operating state or configuration (e.g., a deactivated state in which the motor 124 does not drive the shaft 165 to rotate). 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. Therefore, the cost and / or energy consumption associated with the manufacture and operation of the second compressor 102 may be substantially less than the cost and / or energy consumption associated with the manufacture and operation of the first compressor 101.

[0045] Furthermore, the costs and / or complexity associated with manufacturing the second compressor 102 may be less than the costs and / or complexity of the first compressor 101. For example, the shaft 165 and the plate 122 may be less costly and / or less complex than the various components of the first compressor 101 (such as the impeller, diffuser passages, bearings, shrouds, etc.). Thus, the design of the second compressor 102 may improve the performance (e.g., efficiency) of the vapor compression system 100 without unduly increasing the costs and / or complexity associated with manufacturing and / or operating the vapor compression system 100.

[0046] Further, the second compressor 102 can be easily adjusted. For example, the number of plates 122 implemented in the second compressor 102 can be changed to enable the second compressor 102 to achieve the desired operation (e.g., to achieve the desired operating characteristics of the second compressor 102). As an example, additional plates 122 can be implemented to adjust (e.g., increase, decrease) the amount by which the second compressor 102 pressurizes the heat transfer fluid 109 during operation, to adjust the amount of flow rate at which the second compressor 102 discharges the heat transfer fluid 109 during operation, or to adjust other suitable operating characteristics of the second compressor 102. As another example, the plate 122 can be removed from the second compressor to reduce the pressurization and / or flow rate of the heat transfer fluid 109 directed through the second compressor 102. The configurability of the second compressor 102 can facilitate implementing the second compressor 102 in a variety of different vapor compression systems 100.

[0047] Figure 7 is a schematic diagram of an embodiment of a vapor compression system 100 that includes a first economizer 160 (e.g., economizer 103) and a second economizer 162. In some embodiments, the first economizer 160 and the second economizer 162 may form a portion or all of an economizer system 104. The vapor compression system 100 may also include a second compressor 164 (e.g., an auxiliary compressor, a direct-drive economizer compressor, an auxiliary compressor, a multi-stage compressor, an embodiment of the second compressor 102, a low-flow compressor) configured to receive a heat transfer fluid from the first economizer 160 and the second economizer 162.

[0048] For example, the first economizer 160 may receive the heat transfer fluid 105 from the condenser 34 and separate the heat transfer fluid into a liquid heat transfer fluid 107 (e.g., a substantially liquid heat transfer fluid) and a vapor heat transfer fluid 109 (e.g., a 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 the pressure of the liquid heat transfer fluid 107 received from the first economizer 160, thereby evaporating a portion of the heat transfer fluid 107 within the second economizer 162 and separating the heat transfer fluid 107 into a liquid heat transfer fluid 171 (e.g., a substantially liquid heat transfer fluid) and a vapor heat transfer fluid 173 (e.g., a substantially vapor heat transfer fluid). The second economizer 162 may direct the liquid heat transfer fluid 171 to the evaporator 38 and direct 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 the cooling of the heat transfer fluid 107 before the heat transfer fluid 107 is discharged to the evaporator 38, thereby increasing the amount of cooling provided to the conditioning fluid by the evaporator 38.

[0049] As described above, the second compressor 164 may include a shaft 165 that 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 in the plate groups 166, 168 may have a design similar to the plates 122 of the second compressor 102. In fact, each of the plates 122 of the second compressor 164 may also be configured to drive the flow of a heat transfer fluid (e.g., a vapor heat transfer fluid) received from the economizers 160, 162 via a boundary layer effect. The plate groups 166, 168 may be in a series flow arrangement 175 within the second compressor 164 so that each stage 167, 169 can provide additional pressurization of the heat transfer fluid. For example, the first stage 167 may receive the heat transfer fluid 173 via the first compressor inlet 170, and the first set of plates 166 at the first stage 167 may be configured to receive the heat transfer fluid 173, pressurize the heat transfer fluid 173, and direct the pressurized heat transfer fluid 173 to the second stage 169 via the 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 the compressor outlet 174.

[0050] In some embodiments, the second economizer 162 may direct the 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 the vapor heat transfer fluid 109 into the second stage 169 of the second compressor 164 via the second compressor inlet 176, which directs the vapor heat transfer fluid 109 to the second set of plates 168 and bypasses the first set of plates 166. That is, the vapor heat transfer fluid 173 directed by the second economizer 162 may be pressurized 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 be pressurized at the second stage 169 via the second set of plates 168, rather than being pressurized at the first stage 167 via the first set of plates 166. For 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. To this end, the vapor heat transfer fluid 109 directed by the first economizer 160 may undergo relatively less pressurization to achieve the desired pressure for flowing into the condenser 34, and the vapor heat transfer fluid 173 received from the second economizer 162 may undergo relatively more pressurization to reach the desired pressure level for flowing into the condenser 34. Therefore, the vapor heat transfer fluid 109 directed by the first economizer 160 may be pressurized and directed to the condenser 34 via the second stage 169, 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. Therefore, the heat transfer fluids 109, 173 are output by the second compressor 164 to the condenser 34 as a heat transfer fluid stream 180.

[0051] Figure 8 1 is a schematic diagram of an embodiment of a vapor compression system 100 that includes a first economizer 160, a second economizer 162, and a second compressor 164 (e.g., a low flow compressor) that includes a first stage 167 and a second stage 169. In the illustrated embodiment, the first economizer 160 and the second economizer 162 are part of (e.g., disposed within) an economizer housing 200. For example, the first economizer 160 and the second economizer 162 may be separate chambers, compartments, or volumes within the economizer housing 200 and may be separated from one another within the economizer housing 200 via partitions, walls, dividers, panels, etc. Thus, a single economizer housing 200 may include multiple economizers 160, 162.

[0052] The operation of the economizers 160, 162 may be similar to the operation described herein. That is, the first economizer 160 may receive the heat transfer fluid 105 from the condenser 34, separate the heat transfer fluid 105 into a liquid heat transfer fluid 107 and a 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 the pressure of the liquid heat transfer fluid 107 received from the first economizer 160 to evaporate a portion of the liquid heat transfer fluid 107, thereby producing a liquid heat transfer fluid 171 and a 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.

[0053] The second compressor 164 can be mounted (e.g., directly mounted), fixed (e.g., directly fixed), or coupled (e.g., directly coupled) to the economizer housing 200. For example, the economizer housing 200 can include an interface 201, such as a mounting surface, and the second compressor 164 can be attached to the interface 201, such as via fasteners, adhesives, welds, interference fits, another suitable feature, or any combination thereof. Thus, the second compressor 164 can be fixed within the vapor compression system 100 without utilizing a fixing or mounting system separate from the economizer housing 200. That is, the economizer housing 200 can be configured to, for example, support (e.g., fully support) the second compressor 164 and support the second compressor 164 (e.g., support the weight of the second compressor 164).

[0054] In additional or alternative embodiments, the second compressor 164 may be mounted to a different component of the vapor compression system 100, such as a separate one of the economizers 160, 162 (e.g., a separate housing for 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). Thus, the second compressor 164 may be mounted to an existing vapor compression device of the vapor compression system 100 to reduce manufacturing and / or installation costs or complexity, as well as to limit the physical footprint occupied by the vapor compression system 100, such as compared to a vapor compression system 100 that may utilize a separate support or structure dedicated to securing the second compressor 164 within the vapor compression system 100.

[0055] Fig. 91 is a schematic diagram of an embodiment of a vapor compression system 100 that includes a first economizer 160, a second economizer 162, and a third economizer 220. For example, the economizers 160, 162, 220 may be chambers of a common economizer housing and / or may be separate economizers that have their own respective housings. In some embodiments, the first economizer 160, the second economizer 162, and the third economizer 220 may form a portion or all of the economizer system 104. Additionally, the vapor compression system 100 includes a second compressor 164 (e.g., a low flow compressor) that may include a first stage 167 having a first set of plates 166, a second stage 169 having a second set of plates 168, and a third stage 222 having a third set of plates 224. Each set of plates 166, 168, 224 may be coupled to a shaft 165.

[0056] The first economizer 160 may receive the heat transfer fluid 105 from the condenser 34, reduce the pressure of the heat transfer fluid 105 to separate the heat transfer fluid into a liquid heat transfer fluid 107 and a vapor heat transfer fluid 109, direct the vapor heat transfer fluid 109 to the third stage 222 of the second compressor 164 via the third compressor inlet 226, and direct the liquid heat transfer fluid 107 to the second economizer 162. The second economizer 162 may reduce the pressure of the liquid heat transfer fluid 107 received from the first economizer 160 to evaporate a portion of the liquid heat transfer fluid 107 to produce a liquid heat transfer fluid 171 and a 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 can reduce the pressure of the liquid heat transfer fluid 171 received from the second economizer 162 to evaporate a portion of the liquid heat transfer fluid 171 to produce liquid heat transfer fluid 223 and vapor heat transfer fluid 225, guide the liquid heat transfer fluid 223 to the evaporator 38, and guide the vapor heat transfer fluid 225 to the first stage 167 of the second compressor 164 via the first compressor inlet 170.

[0057] 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 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 the 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.

[0058] In additional or alternative embodiments, the second compressor 164 may include any suitable number of stages 167, 169, 222 (e.g., the same number of stages as the number of economizers, a different number of stages than the number of economizers). The plate groups 166, 168, 224 associated with each stage 167, 169, 222 may include any suitable number of plates, such as the same or different numbers of plates from each other. In addition, although the stages 167, 169, 222 of the second compressor 164 described herein are in a series flow arrangement, in additional or alternative embodiments, the stages 167, 169, 222 may be in a parallel flow arrangement. For example, each set of plates 166, 168, 224 may be coupled to a different shaft, and may each, for example, discharge the pressurized heat transfer fluid directly to the condenser 34.

[0059] Although the present technology is described as being realized by using boundary layer type auxiliary compressor to pressurize the relatively low flow heat transfer fluid guided by economizer, it should be understood that other types of low flow compressors can be used in other embodiments.For example, auxiliary compressor may include any other suitable type of compressor (for example, low flow compressor, low flow coefficient compressor), such as rotary compressor, reciprocating compressor, scroll compressor, centrifugal compressor, oil-free compressor, compact compressor and / or any other suitable type of compressor configured to pressurize the heat transfer fluid of low flow.In fact, any suitable type of auxiliary compressor (for example, relative to the main compressor of vapor compression system) configured to reduce flow and / or capacity may be included.In certain embodiments, this type of compressor can be driven by direct drive motor.For this reason, auxiliary compressor can have lower cost, limited complexity, smaller physical footprint, lower energy consumption, etc.In addition, any aforementioned type of auxiliary compressor may have a multi-stage structure, so that it is possible to receive corresponding heat transfer fluid flow from different economizers and pressurize it.

[0060] Although only certain features and embodiments of the present disclosure are shown and described, many modifications and changes (such as the size, dimensions, structure, shape and proportion of various elements, changes in parameter values ​​(e.g., temperature, pressure, etc.), installation arrangements, material use, color, orientation, etc.) may occur to those skilled in the art without substantially departing from the novel teachings and advantages of the subject matter described in the claims. The order or sequence of any process or method steps may be changed or reordered according to alternative embodiments. Therefore, it is to be noted that the appended claims are intended to cover all such modifications and changes that fall within the true spirit of the present disclosure. In addition, in order to provide a concise description of the exemplary embodiments, all features of the actual implementation may not be described (i.e., those features that are not related to the best mode currently contemplated for implementing the present disclosure, or those features that are not related to implementing the claimed embodiments). It should be understood that in the development of any such actual implementation, as in any engineering technology or design project, a large number of implementation-specific decisions may be made. Such development work may be complex and time-consuming, but for ordinary technicians who benefit from the present disclosure, these are routine tasks of design, manufacture and production without excessive experimentation.

[0061] The techniques presented and claimed herein refer to and apply to substantial objects and specific examples of a practical nature that improve the technical field of the invention in a demonstrable manner and are therefore not abstract, intangible, or purely theoretical. In addition, if any claim appended to the end of this specification contains one or more elements expressed as "means for [performing] [the function] ..." or "steps for [performing] [the function] ...", it is expected that such elements will be interpreted in accordance with 35 U.S.C. 112(f). However, for any claim containing elements specified in any other manner, it is intended that such elements will not be interpreted in accordance with 35 U.S.C. 112(f).

Claims

1. A heating, ventilation, air conditioning and / or refrigeration (HVAC&R) system comprising: an economizer configured to receive a heat transfer fluid from the condenser, wherein the economizer is configured to separate the heat transfer fluid into a liquid heat transfer fluid and a vapor heat transfer fluid; and A low flow compressor is 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.

2. The HVAC&R system of claim 1 , wherein the low flow compressor comprises a shaft and a plate coupled to the shaft, wherein the shaft is configured to rotate the plate so that the plate directs the vapor heat transfer fluid through the low flow compressor via a boundary layer effect.

3. The HVAC&R system of claim 2, wherein the plate comprises a flat geometric shape.

4. The HVAC&R system of claim 2, wherein the economizer is a first economizer, the HVAC&R system comprising a second economizer configured to receive the liquid heat transfer fluid from the first economizer and separate the liquid heat transfer fluid into an additional liquid heat transfer fluid and an additional vapor heat transfer fluid, and the second economizer configured to direct the additional vapor heat transfer fluid to the low flow compressor.

5. The HVAC&R system of claim 4, wherein the plate is a first plate, the low flow compressor includes a second plate coupled to the shaft, and the shaft is configured to rotate the second plate so that the second plate directs the additional vapor heat transfer fluid received from the second economizer through the low flow compressor via a boundary layer effect.

6. The HVAC&R system of claim 5, wherein the first plate and the second plate are arranged along the axis in a series flow arrangement, the second plate is configured to direct the additional vapor heat transfer fluid received from the second economizer to the first plate, and the first economizer is configured to direct the vapor heat transfer fluid to the first plate and bypass the second plate.

7. The HVAC&R system of claim 1 , wherein the low flow compressor comprises: a shaft and a plate coupled to the shaft, wherein the plate surrounds the shaft, and the shaft is configured to rotate the plate so that the plate directs the vapor heat transfer fluid through the low flow compressor; and A motor is coupled to the shaft and configured to drive rotation of the shaft.

8. The HVAC&R system of claim 7, wherein the motor is a direct drive motor.

9. The HVAC&R system of claim 7, wherein the motor is a single speed motor.

10. The HVAC&R system of claim 1, wherein the low flow compressor is mounted to a housing of the economizer at an interface between the economizer and the low flow compressor.

11. The HVAC&R system of claim 1 , wherein the economizer is configured to direct the liquid heat transfer fluid to an evaporator, the evaporator being configured to place the liquid heat transfer fluid in heat exchange relationship with a conditioning fluid.

12. A heating, ventilation, air conditioning and / or refrigeration (HVAC&R) system comprising: an economizer configured to separate a heat transfer fluid into a liquid heat transfer fluid and a vapor heat transfer fluid; and A compressor configured to receive the vapor heat transfer fluid from the economizer, wherein the compressor includes a shaft and a plate coupled to the shaft, the shaft being configured to rotate the plate to drive the vapor heat transfer fluid to flow through the compressor via a boundary layer effect imposed by a surface of the plate and to pressurize the vapor heat transfer fluid to produce a pressurized vapor heat transfer fluid, and wherein the compressor is configured to direct the pressurized vapor heat transfer fluid to a heat exchanger of the HVAC&R system.

13. The HVAC&R system of claim 12, wherein the plate comprises a flat geometric shape.

14. The HVAC&R system of claim 12, wherein the plate is one of a plurality of plates coupled to the shaft, wherein the plurality of plates are spaced apart from one another along the shaft to form gaps along the shaft between adjacent ones of the plurality of plates.

15. The HVAC&R system of claim 12, wherein the economizer is a first economizer, the HVAC&R system comprising a second economizer configured to receive the liquid heat transfer fluid from the first economizer and separate the liquid heat transfer fluid into an additional liquid heat transfer fluid and an additional vapor heat transfer fluid, and the second economizer configured to direct the additional vapor heat transfer fluid to the compressor.

16. The HVAC&R system of claim 15, wherein the first economizer and the second economizer are disposed within a housing, and wherein the low flow compressor is mounted to the housing.

17. The HVAC&R system of claim 12, comprising: a motor of the compressor, wherein the motor is coupled to the shaft and configured to drive rotation of the shaft; and A control system wherein the control system is configured to operate the electric machine without a variable speed drive (VSD).

18. A heating, ventilation, air conditioning and / or refrigeration (HVAC&R) system comprising: a first compressor configured to direct a heat transfer fluid to a condenser; an economizer configured to receive the heat transfer fluid from the condenser, wherein the economizer is configured to separate the heat transfer fluid into a liquid heat transfer fluid and a vapor heat transfer fluid; and a second compressor comprising a plate, wherein the second compressor is configured to receive the vapor heat transfer fluid from the economizer, wherein the second compressor is configured to rotate the plate to direct the vapor heat transfer fluid to the condenser via a boundary layer effect exerted on the vapor heat transfer fluid by a surface of the plate.

19. The HVAC&R system of claim 18, wherein a majority of the surface of the plate has a flat geometry.

20. The HVAC&R system of claim 18, wherein the first compressor is configured to pressurize the vapor heat transfer fluid at a first pressurization amount, the second compressor is configured to pressurize the vapor heat transfer fluid at a second pressurization amount, and wherein the first pressurization amount is greater than the second pressurization amount.

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