Compressor System for Hvac&r System

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 Jun. 17, 2022, which is herein incorporated by reference in its entirety for all purposes.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Turning now to the drawings,is a perspective view of an embodiment of an environment for a heating, ventilation, air conditioning, and refrigeration (HVAC&R) systemin a buildingfor a typical commercial setting. The HVAC&R systemmay include a vapor compression system(e.g., a chiller) that supplies a chilled liquid, which may be used to cool the building. The HVAC&R systemmay also include a boilerto supply warm liquid to heat the buildingand an air distribution system which circulates air through the building. The air distribution system can also include an air return duct, an air supply duct, and/or an air handler. In some embodiments, the air handlermay include a heat exchanger that is connected to the boilerand the vapor compression systemby conduits. The heat exchanger in the air handlermay receive either heated liquid from the boileror chilled liquid from the vapor compression system, depending on the mode of operation of the HVAC&R system. The HVAC&R systemis shown with a separate air handler on each floor of building, but in other embodiments, the HVAC&R systemmay include air handlersand/or other components that may be shared between or among floors.

are embodiments of the vapor compression systemthat can be used in the HVAC&R system. The vapor compression systemmay circulate a heat transfer fluid (e.g., a refrigerant) through a circuit starting with a compressor. The circuit may also include a condenser, an expansion valve(s) or device(s), and a liquid chiller or an evaporator. The vapor compression systemmay further include a control panelthat has an analog to digital (A/D) converter, a microprocessor, a non-volatile memory, and/or an interface board.

Some examples of fluids that may be used as heat transfer fluids (e.g., refrigerants) in the vapor compression systemare 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 systemmay 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.

In some embodiments, the vapor compression systemmay use one or more of a variable speed drive (VSDs), a motor, the compressor, the condenser, the expansion valve or device, and/or the evaporator. The motormay drive the compressorand may be powered by a variable speed drive (VSD). The VSDreceives 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. In other embodiments, the motormay be powered directly from an AC or direct current (DC) power source. The motormay 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.

The compressorcompresses a heat transfer fluid vapor and delivers the vapor to the condenserthrough a discharge passage. In some embodiments, the compressormay be a centrifugal compressor. The heat transfer fluid vapor delivered by the compressorto the condensermay transfer heat to a cooling fluid (e.g., water or air) in the condenser. The heat transfer fluid vapor may condense to a heat transfer fluid liquid in the condenseras a result of thermal heat transfer with the cooling fluid. The liquid heat transfer fluid from the condensermay flow through the expansion deviceto the evaporator. In the illustrated embodiment of, the condenseris water cooled and includes a tube bundleconnected to a cooling tower, which supplies the cooling fluid to the condenser.

The liquid heat transfer fluid delivered to the evaporatormay absorb heat from a conditioning fluid, which may or may not be the same cooling fluid used in the condenser. The liquid heat transfer fluid in the evaporatormay undergo a phase change from the liquid heat transfer fluid to a heat transfer fluid vapor. As shown in the illustrated embodiment of, the evaporatormay include a tube bundlehaving a supply lineS and a return lineR connected to a cooling load. The conditioning fluid of the evaporator(e.g., water, ethylene glycol, calcium chloride brine, sodium chloride brine, or any other suitable fluid) enters the evaporatorvia return lineR and exits the evaporatorvia supply lineS. The evaporatormay reduce the temperature of the conditioning fluid in the tube bundlevia thermal heat transfer with the heat transfer fluid. The tube bundlein the evaporatorcan include a plurality of tubes and/or a plurality of tube bundles. In any case, the vapor heat transfer fluid exits the evaporatorand returns to the compressorby a suction line to complete the cycle.

is a schematic of the vapor compression systemwith an intermediate circuitincorporated between condenserand the expansion device. The intermediate circuitmay have an inlet linethat is directly fluidly connected to the condenser. In other embodiments, the inlet linemay be indirectly fluidly coupled to the condenser. As shown in the illustrated embodiment of, the inlet lineincludes a first expansion devicepositioned upstream of an intermediate vessel. In some embodiments, the intermediate vesselmay be a flash tank (e.g., a flash intercooler, an economizer). In other embodiments, the intermediate vesselmay be configured as a heat exchanger or a “surface economizer.” In the illustrated embodiment of, the intermediate vesselis used as a flash tank, and the first expansion deviceis configured to lower the pressure of (e.g., expand) the liquid heat transfer fluid received from the condenser. During the expansion process, a portion of the liquid may vaporize, and thus, the intermediate vesselmay be used to separate the vapor from the liquid received from the first expansion device.

Additionally, the intermediate vesselmay 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(e.g., due to a rapid increase in volume experienced when entering the intermediate vessel). The vapor in the intermediate vesselmay be drawn by the compressorthrough a suction lineof the compressor. In other embodiments, the vapor in the intermediate vessel may be drawn to an intermediate stage of the compressor(e.g., not the suction stage). The liquid that collects in the intermediate vesselmay be at a lower enthalpy than the liquid heat transfer fluid exiting the condenserbecause of the expansion in the expansion deviceand/or the intermediate vessel. The liquid from intermediate vesselmay then flow in linethrough a second expansion deviceto the evaporator.

It should be appreciated that any of the features described herein may be incorporated with the vapor compression systemor 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, and a compressor, such as the compressor. The discussion below describes the present techniques incorporated with embodiments of the compressorconfigured 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 compressorand HVAC&R system.

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.

With the foregoing in mind,is a schematic of an embodiment of a vapor compression systemthat includes a first compressor(e.g., the compressor, a main compressor, a primary compressor), the condenser, the evaporator, and an economizer systemhaving at least one economizer(e.g., the intermediate vessel). The vapor compression systemalso includes a second compressor(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. The economizermay receive a flow of heat transfer fluidfrom the condenserand separate (e.g., substantially separate) the heat transfer fluidinto liquid heat transfer fluidand vapor heat transfer fluid. The second compressormay draw the vapor heat transfer fluidfrom the economizer, compress the vapor heat transfer fluid, and discharge the compressed vapor heat transfer fluidto the condenser. As an example, the second compressor, instead of the first compressor, may receive the vapor heat transfer fluidfrom economizerand direct the vapor heat transfer fluidfrom the economizerto the condenser. The economizermay be configured to discharge the liquid heat transfer fluidto the evaporator, for example.

Additionally, the second compressormay increase the pressure of the vapor heat transfer fluidtoward that of vapor heat transfer fluidpressurized by the first compressor. For example, a first pressure of the vapor heat transfer fluiddirected from the first compressorinto the condenser(e.g., via a first condenser inlet) may be similar or substantially the same as a second pressure of the vapor heat transfer fluiddirected from the second compressorinto the condenser(e.g., via a second condenser inlet). The pressurization of the heat transfer fluid flows,to approximately the same pressure may block backflow of heat transfer fluid (e.g., through the first condenser inlet, through the second condenser inlet) that may otherwise occur as a result of a pressure differential between the respective heat transfer fluid flows,from the first compressorand from the economizer. For example, a desirable flow (e.g., a target flow rate) of heat transfer fluid through the vapor compression systemand/or a desirable cooling of the heat transfer fluid provided via the condensermay be achieved.

An amount of pressurization provided by the second compressormay be less than an amount of pressurization provided by the first compressor. By way of example, the pressure of the vapor heat transfer fluiddirected from the economizerto the second compressormay be greater than the pressure of the heat transfer fluiddirected from the evaporatorto the first compressor. As such, a first pressure differential between the pressure of the heat transfer fluidreceived by the second compressorand a corresponding target pressure for pressurization of the heat transfer fluidby the second compressormay be less than a second pressure differential between the pressure of the heat transfer fluidreceived by the first compressorand a corresponding target pressure for pressurization of the heat transfer fluidby the first compressor.

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

is a schematic of an embodiment of the vapor compression systemthat includes the second compressor. The second compressormay include a boundary layer compressor (e.g., a cohesion-type compressor, a bladeless compressor, a plate compressor, a low flow compressor) that includes a shaftand one or more plates(e.g., one plate, two plates, three or more plates, planar plates, disks, circumferential plates, circular plates) coupled to the shaft. Each platemay extend about (e.g., completely about) a circumference of the shaft. That is, each platemay surround and/or encircle the shaft. However, as described herein, other types of compressors may be incorporated with the vapor compression systemas the second compressor. The shaftmay be coupled to a motor, which may be configured to rotate the shaftto drive rotation of the plates. In some embodiments, the shaftmay form a portion of the motor(e.g., the shaftmay be a shaft of the motor). Rotation of the platesmay cause pressurization of heat transfer fluidreceived from the economizer. As an example, the second compressormay include a compressor inletconfigured to receive the vapor heat transferfluid from the economizer, and each platemay receive the vapor heat transfer fluidvia the compressor inlet. Rotation of the platesmay drive the vapor heat transfer fluidradially toward a compressor outlet, which may discharge the vapor heat transfer fluidfrom the second compressortoward the condenser(e.g., via the second condenser inlet). A cross-sectional area of the flow path of the vapor heat transfer fluidthrough the second compressorvia rotation of the platesmay decrease from the compressor inletto the compressor outletin order to enable pressurization of the vapor heat transfer fluid. For instance, a size of the compressor outletmay be less than a size of the compressor inlet. For clarity, as used herein, a “low flow compressor” may be a compressor (e.g., the second compressor) that includes one or more of the plates(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. 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 platesinstead of, for example, an impeller that drives movement of the heat transfer fluid via blades (e.g., impeller blades).

In some embodiments, each platemay utilize boundary layer effects, instead of blades, to drive flow of the vapor heat transfer fluidfrom the compressor inlettoward the compressor outlet. Indeed, the vapor heat transfer fluidmay flow along a first direction(e.g., an intake direction) into the second compressorand onto respective surfaces(e.g., opposing surfaces) of the plates. During rotation of the plates, the surfacesmay cause the flow of the vapor heat transfer fluidto adjust from the first directionto a second direction(e.g., a discharge direction), which may be crosswise to the first direction, toward the compressor outlet. In some embodiments, each platemay have a generally flat geometry (e.g., planar geometry). For example, in some embodiments, a majority of the surfacesof the plates(e.g., 60 percent of a surface area of the surfaces, 70 percent of a surface area of the surfaces, 80 percent of a surface area of the surfaces, 90 percent of a surface area of the surfaces, 100 percent of a surface area of the surfaces) may each include a substantially flat or planar geometry. Additionally or alternatively, the surfaceof each platemay 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.

In certain embodiments, at least one of the platesmay 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 compressorcaused by rotation of the platesand therefore increase stability of the second compressor. Furthermore, in embodiments in which the second compressorincludes multiples plates, the platesmay be spaced apart from one another (e.g., along a rotational axis of the shaft) to form gapshaving suitable sizes to enable each plateto receive the vapor heat transfer fluidand to drive flow of the vapor heat transfer fluidtoward the compressor outlet. For example, the gapsbetween the platesmay be sized based on a viscosity of vapor heat transfer fluidreceived by the second compressor. In some embodiments, a dimension of the gapbetween each of the platesmay be substantially the same. In other embodiments, a dimension of a corresponding gapbetween a set of the platesmay be different than (e.g., greater than, less that) a dimension of a corresponding gapbetween another set of plates. In any case, such features of the second compressormay enable sufficient pressurization of the heat transfer fluidreceived by the second compressorfrom the economizer(e.g., a relatively low flow of heat transfer fluidas compared to the flow of heat transfer fluiddirected from the condenserto the economizerand/or directed from the evaporatorto the first compressor).

Additionally, the vapor compression systemmay include a control system(e.g., the control panelconfigured to operate the first compressor, a control system separate from the control panel), which may be an automation controller and/or an electronic controller, configured to operate the second compressor. The control systemmay include a memoryand processing circuitry. The memorymay 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. The processing circuitrymay be configured to execute such instructions stored in the memory. As an example, the processing circuitrymay 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.

In some embodiments, the motormay be a direct drive motor that may be directly coupled to the shaft(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. In this way, fewer components may be utilized to enable the motorto drive operation of the second compressor. The motormay additionally or alternatively be a single speed drive (e.g., a single speed motor). Thus, the control systemmay operate the motorat a fixed speed and reduce complexity associated with operation of the second compressor. For example, because the motormay be a single speed drive, the control systemmay be configured to operate the motorwithout use of a variable speed drive (VSD). That is, the control systemmay send signals (e.g., control signals, instructions, electrical current) to transition the motorbetween an operational state or configuration (e.g., in which the motormay drive rotation of the shaftat a fixed speed or target speed) and an idle or non-operational state or configuration (e.g., a deactivated state in which the motordoes not drive rotation of the shaft). In certain embodiments, the speed at which the motoroperates the second compressormay be lower than the speed at which the motoroperates the first compressor. As such, costs and/or energy consumption associated with manufacture and operation of the second compressormay be substantially less than that associated with manufacture and operation of the first compressor.

Furthermore, costs and/or complexity associated with manufacture of the second compressormay be less than that of the first compressor. By way of example, the shaftand the platesmay 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. As a result, the design of the second compressormay improve performance (e.g., an efficiency) of the vapor compression systemwithout excessively increasing costs and/or complexity associated with the manufacture and/or operation of the vapor compression system.

Further still, the second compressormay be readily adjustable. For instance, a quantity of platesimplemented in the second compressormay be changed to enable the second compressorto achieve a desirable operation (e.g., to achieve desired operational characteristics of the second compressor). As an example, additional platesmay be implemented to adjust (e.g., increase, decrease) a magnitude by which the second compressorpressurizes heat transfer fluidduring operation, to adjust a magnitude of a flow rate at which the second compressordischarges heat transfer fluidduring operation, or to adjust other suitable operational characteristics of the second compressor. As another example, platesmay be removed from the second compressor to reduce pressurization and/or flow rate of the heat transfer fluiddirected through the second compressor. The configurability of the second compressormay facilitate implementation of the second compressorin various different vapor compression systems.

is a schematic of an embodiment of the vapor compression systemthat includes a first economizer(e.g., the economizer) and a second economizer. In some embodiments, the first and second economizers,may form a portion of or all of the economizer system. The vapor compression systemmay also include a second compressor(e.g., an auxiliary compressor, a direct drive an economizing compressor, a secondary compressor, a multistage compressor, an embodiment of the second compressor, a low flow compressor) configured to receive heat transfer fluid from the first and second economizers,.

For example, the first economizermay receive heat transfer fluidfrom the condenserand separate the heat transfer fluid into liquid heat transfer fluid(e.g., substantially liquid heat transfer fluid) and vapor heat transfer fluid(e.g., substantially vapor heat transfer fluid). The first economizermay direct the vapor heat transfer fluidto the second compressorfor pressurization and discharge back to the condenser, and the first economizermay direct the liquid heat transfer fluidto the second economizer. The second economizermay reduce a pressure of the liquid heat transfer fluidreceived from the first economizer, thereby vaporizing a portion of the heat transfer fluidand separating the heat transfer fluidinto liquid heat transfer fluid(e.g., substantially liquid heat transfer fluid) and vapor heat transfer fluid(e.g., substantially vapor heat transfer fluid) within the second economizer. The second economizermay direct the liquid heat transfer fluidto the evaporatorand the vapor heat transfer fluidto the second compressorfor pressurization and discharge to the condenser. By further reducing the pressure of the heat transfer fluid, the second economizermay increase cooling of the heat transfer fluidprior to discharge to the evaporator, thereby increasing an amount of cooling provided by the evaporatorto the conditioning fluid.

As discussed above, the second compressormay include the shaft, which may be coupled to the motor. The second compressormay include a first stagehaving a first set of platescoupled to the shaftand a second stagehaving a second set of platescoupled to the shaft. Each plate of the sets of plates,may have a similar design as that of the platesof the second compressor. Indeed, each of the platesof the second compressormay also be configured to drive flow of the heat transfer fluid (e.g., vapor heat transfer fluid) received from the economizers,via boundary layer effects. The sets of plates,may be in a series flow arrangementwithin the second compressorto enable each stage,to provide additional pressurization of the heat transfer fluid. For example, the first stagemay receive heat transfer fluidvia a first compressor inlet, and the first set of platesat the first stagemay be configured to receive heat transfer fluid, pressurize the heat transfer fluid, and direct the pressurized heat transfer fluidto the second stagevia an intermediate inlet. At the second stage, the second set of platesmay further pressurize the heat transfer fluidand discharge the heat transfer fluidto the condenservia a compressor outlet.

In some embodiments, the second economizermay direct vapor heat transfer fluidinto the first stageof the second compressorvia the first compressor inletfor compression via the first set of plates. The first economizermay direct vapor heat transfer fluidinto the second stageof the second compressorvia a second compressor inletthat directs the vapor heat transfer fluidto the second set of platesand bypass the first set of plates. That is, the vapor heat transfer fluiddirected by the second economizermay undergo pressurization at both the first stageand the second stagevia the first set of platesand the second set of plates. However, the vapor heat transfer fluiddirected by the first economizermay undergo pressurization at the second stagevia the second set of platesand not at the first stagevia the first set of plates. By way of example, the vapor heat transfer fluiddirected by the first economizermay be at a higher pressure than the vapor heat transfer fluiddirected by the second economizer. For this reason, the vapor heat transfer fluiddirected by the first economizermay undergo relatively less pressurization to achieve a desirable pressure for flow into the condenser, and the vapor heat transfer fluidreceived from the second economizermay undergo relatively more pressurization to achieve the desirable pressure level for flow into the condenser. Therefore, the vapor heat transfer fluiddirected by the first economizermay be pressurized via the second stageand directed to the condenser, and the vapor heat transfer fluiddirected by the second economizermay be pressurized via the first stage, further pressurized via the second stage, and then directed to the condenser. The heat transfer fluids,are thus output by the second compressorto the condenseras a heat transfer fluid flow.

is a schematic of an embodiment of the vapor compression systemthat includes the first economizer, the second economizer, and the second compressor(e.g., a low flow compressor) that includes the first stageand the second stage. In the illustrated embodiment, the first economizerand the second economizerare a part of (e.g., disposed within) an economizer enclosure. For example, the first economizerand the second economizermay be separate chambers, compartments, or volumes within the economizer enclosureand may be separated from one another within the economizer enclosurevia a partition, a wall, a divider, a plate, and the like. Thus, a single economizer enclosuremay include multiple economizers,.

Operation of the economizers,may be similar to that as described herein. That is, the first economizermay receive heat transfer fluidfrom the condenser, separate the heat transfer fluidinto liquid heat transfer fluidand vapor heat transfer fluid, direct the vapor heat transfer fluidto the second stageof the second compressor, and direct the liquid heat transfer fluidto the second economizer. The second economizermay reduce a pressure of the liquid heat transfer fluidreceived from the first economizerto vaporize a portion of the liquid heat transfer fluidto produce liquid heat transfer fluidand vapor heat transfer fluid, direct the liquid heat transfer fluidto the evaporator, and direct the vapor heat transfer fluidto the first stageof the second compressor.

The second compressormay be mounted (e.g., directly mounted), secured (e.g., directly secured), or coupled (e.g., directly coupled) to the economizer enclosure. For example, the economizer enclosuremay include an interface, such as a mounting surface, and the second compressormay be attached to the interface, such as via a fastener, an adhesive, a weld, an interference fit, another suitable feature, or any combination thereof. Thus, the second compressormay be secured within the vapor compression systemwithout utilizing a securement or mounting system that is separate from the economizer enclosure. That is, the economizer enclosuremay be configured to support (e.g., fully support) the second compressorand brace the second compressor(e.g., support a weight of the second compressor), for example.

In additional or alternative embodiments, the second compressormay be mounted to a different component of the vapor compression system, such as an individual one of the economizers,(e.g., separate enclosures of the economizers,), the condenser(e.g., a condenser shell), the evaporator(e.g., an evaporator shell), and/or the first compressor(e.g., a compressor skid). As a result, the second compressormay be mounted to existing vapor compression equipment of the vapor compression systemto reduce a manufacturing and/or installation cost or complexity, as well as limit a physical footprint occupied by the vapor compression system, such as in comparison to a vapor compression systemthat may utilize a separate support or structure dedicated to securement of the second compressorwithin the vapor compression system.

is a schematic of an embodiment of the vapor compression systemthat includes the first economizer, the second economizer, and a third economizer. For example, the economizers,,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,,may form a portion of or all of the economizer system. Additionally, the vapor compression systemincludes the second compressor(e.g., a low flow compressor), which may include the first stagehaving the first set of plates, the second stagehaving the second set of plates, and a third stagehaving a third set of plates. Each of the sets of plates,,may be coupled to the shaft.

The first economizermay receive heat transfer fluidfrom the condenser, reduce the pressure of the heat transfer fluidto separate the heat transfer fluid into liquid heat transfer fluidand vapor heat transfer fluid, direct the vapor heat transfer fluidto the third stageof the second compressorvia a third compressor inlet, and direct the liquid heat transfer fluidto the second economizer. The second economizermay reduce a pressure of the liquid heat transfer fluidreceived from the first economizerto vaporize a portion of the liquid heat transfer fluidto produce liquid heat transfer fluidand vapor heat transfer fluid, direct the liquid heat transfer fluidto the third economizer, and direct the vapor heat transfer fluidto the second stageof the second compressorvia the second compressor inlet. The third economizermay reduce a pressure of the liquid heat transfer fluidreceived from the second economizerto vaporize a portion of the liquid heat transfer fluidto produce liquid heat transfer fluidand vapor heat transfer fluid, direct the liquid heat transfer fluidto the evaporator, and direct the vapor heat transfer fluidto the first stageof the second compressorvia the first compressor inlet.

The first stageof the second compressormay receive the vapor heat transfer fluidfrom the third economizer, and the first set of platesmay pressurize the vapor heat transfer fluidand direct the pressurized vapor heat transfer fluidto the second stagevia the intermediate inlet. The second stagemay receive the vapor heat transfer fluid from the first stageand/or from the second economizer, and the second set of platesmay pressurize the vapor heat transfer fluid and direct the pressurized vapor heat transfer fluid to the third stagevia an additional intermediate inlet. The third stagemay receive the vapor heat transfer fluid from the second stageand/or from the first economizer, and the third set of platesmay pressurize the vapor heat transfer fluid and discharge the pressurized vapor heat transfer fluidto the condenservia the compressor outlet.

In additional or alternative embodiments, the second compressormay include any suitable quantity of stages,,(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,,associated with the respective stages,,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,,of the second compressordescribed herein are in a series flow arrangement, the stages,,may be in a parallel flow arrangement in an additional or alternative embodiment. For example, each set of plates,,may be coupled to a different shaft, and may each, for instance, discharge pressurized heat transfer fluid directly to the condenser.

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.

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.

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 [perform]ing [a function] . . . ” or “step for [perform]ing [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).