Lubricant Separation System for Hvac&r System

This application claims priority from and the benefit of U.S. Provisional Application No. 63/404,814, entitled “OIL PURIFIER FOR AN HVAC SYSTEM,” filed Sep. 8, 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.

Heating, ventilation, air conditioning, and refrigeration (HVAC&R) systems, such as 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 HVAC&R system. The HVAC&R system may include a working fluid circuit configured to 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 HVAC&R system. For example, the HVAC&R system may include a heat exchanger configured to receive the working fluid and the conditioning fluid to place the working fluid in the heat exchange relationship with the conditioning fluid. The conditioning fluid may be directed from the heat exchanger to other equipment, such as air handlers, to condition other fluids, such as air in a building. The HVAC&R system may also include other components, such as a compressor configured to pressurize the working fluid and direct the working fluid through the HVAC&R system. In many applications, the HVAC&R system may include a lubrication system configured to supply a lubricant to components of the HVAC&R system, such as the compressor. Unfortunately, the working fluid and the lubricant may mix or otherwise be combined within the HVAC&R system, which may reduce the efficiency of the HVAC&R system.

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 refrigeration (HVAC&R) system includes an evaporator disposed along a working fluid circuit, where the evaporator is configured to transfer heat between a working fluid and a conditioning fluid, and a lubricant separation system. The lubricant separation system includes a lubricant separation heat exchanger configured to receive a mixture of the working fluid and a lubricant from the evaporator and to transfer heat from a flow of heated fluid to the mixture to separate the working fluid from the lubricant. The lubricant separation system is also configured to direct the working fluid separated from the lubricant to the evaporator.

In another embodiment, a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system includes an evaporator disposed along a working fluid circuit and a lubricant separation heat exchanger configured to place a mixture of working fluid and lubricant received from the evaporator in a heat exchange relationship with a flow of heated fluid received from a heated fluid source to separate the mixture into an evaporated working fluid and a separated lubricant. The lubricant separation heat exchanger includes a first inlet configured to receive the mixture from the evaporator, a second inlet configured receive the flow of heated fluid from the heated fluid source, a first outlet configured to direct the evaporated working fluid to the evaporator, and a second outlet configured to discharge the separated lubricant from the lubricant separation heat exchanger.

In another embodiment, a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system includes an evaporator disposed along a working fluid circuit, a compressor system disposed along the working fluid circuit and having a centrifugal compressor configured to direct a working fluid along the working fluid circuit, a lubricant reservoir configured to supply a lubricant to the centrifugal compressor, and a lubricant separation system having a lubricant separation heat exchanger. The lubricant separation heat exchanger is configured to transfer heat from a heated flow of lubricant received from the lubricant reservoir to a mixture of working fluid and lubricant received from the evaporator to separate the mixture into an evaporated working fluid and a separated lubricant. The lubricant separation system is configured to direct the evaporated working fluid from the lubricant separation heat exchanger to the evaporator, to direct the heated flow of lubricant from the lubricant separation heat exchanger to the compressor system, and to direct the separated lubricant to the lubricant reservoir.

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 refrigeration (HVAC&R) system, such as a chiller or chiller system (e.g., centrifugal chiller), having a vapor compression system. The vapor compression system (e.g., a vapor compression circuit) may circulate a working fluid (e.g., a heat transfer fluid, a refrigerant) through a working fluid circuit in order to cool and/or heat a conditioning fluid (e.g., water). The HVAC&R system may then direct the conditioning fluid to other equipment to condition a space and/or a component serviced by the HVAC&R system. The vapor compression system may include one or more heat exchangers configured to enable transfer of thermal energy (e.g., heat) between the working fluid and another fluid, such as the conditioning fluid. For example, the vapor compression system may include an evaporator configured to place the working fluid in a heat exchange relationship with the conditioning fluid to enable heat transfer from the conditioning fluid to the working fluid in order to cool the conditioning fluid (e.g., reduce a temperature of the conditioning fluid).

The vapor compression system may also include a compressor (e.g., compressor system, centrifugal compressor) disposed along the working fluid circuit. The compressor may operate to drive or force flow of the working fluid along the working fluid circuit. As will be appreciated, the compressor may include one or more components, such as an impeller, a shaft, and/or other components, configured to rotate during operation of the compressor. To this end, the compressor may also include one or more bearings configured to enable and/or facilitate rotation of components of the compressor, such as a shaft of the compressor. The bearings may have any suitable configuration or design and may include, for example, magnetic bearings, roller bearings, ball bearings, bearing surfaces, fluid bearings, hydrostatic bearings, hydrodynamic bearings, radial bearings, thrust bearings, active bearings, passive bearings, another type of bearing, or any combination thereof. In some embodiments, the bearings may utilize a lubricant (e.g., oil) to facilitate improved rotation of one or more components of the compressor. Unfortunately, in certain existing systems, an amount (e.g., a portion) of lubricant supplied to the compressor may become mixed with the working fluid circulated by the compressor. In some instances, lubricant mixed or entrained within the working fluid may be directed to other components of the working fluid circuit, such as one or more heat exchangers of the HVAC&R system. It is desirable to collect lubricant within the working fluid circuit and direct the lubricant back to the compressor for utilization with the bearings and/or other lubricated components of the compressor. For example, lubricant within the evaporator of the HVAC&R system may be at least partially separated from the working fluid within the evaporator as working fluid evaporates within the evaporator. Unfortunately, lubricant collected for return to the compressor may include a remaining amount of working fluid entrained within the lubricant, which may reduce effectiveness of the lubricant to lubricate components within the compressor.

Thus, it is now recognized that improved systems and methods for separating working fluid (e.g., refrigerant) and lubricant (e.g., oil) within a vapor compression system are desired. Accordingly, the present disclosure is directed to a lubricant separation system for the vapor compression system. The lubricant separation system is configured to enable improved separation of working fluid and lubricant that is mixed together within the working fluid circuit of the vapor compression system. In particular, the lubricant separation system includes a heat exchanger configured to receive a mixture of lubricant and working fluid that is collected within the working fluid circuit, such as collected within an evaporator of the working fluid circuit. The heat exchanger may also receive a heated fluid, such as heated lubricant, and may place the heated fluid in a heat exchange relationship with the mixture of lubricant and working fluid. Specifically, the heat exchanger may enable transfer of heat from the heated fluid to the mixture of lubricant and working fluid. In this way, working fluid within the mixture of lubricant and working fluid may evaporate and thereby separate from the lubricant. The evaporated working fluid may be directed back to the evaporator or other suitable portion of the working fluid circuit, while the lubricant may be directed back to the compressor for use as a lubricating fluid. By enabling improved separation of mixed working fluid and lubricant, the present techniques enable improved operation of the vapor compression system. For example, the lubricant directed back to the compressor may be more concentrated and may better function to lubricate components within the compressor. Additionally, the working fluid circulated through the working fluid circuit may include less lubricant mixed therein, which may increase efficiency of the vapor compression circuit.

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 working fluid (e.g., a heat transfer fluid, 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 working fluids in the vapor compression systemare hydrofluorocarbon (HFC) based refrigerants, for example, R-410A, R-407, R-134a, R-1234ze, R1233zd, hydrofluoro olefin (HFO), “natural” refrigerants like ammonia (NH3), R-717, carbon dioxide (CO2), R-744, or hydrocarbon based refrigerants, water vapor, or any other suitable refrigerant. In some embodiments, the vapor compression systemmay be configured to efficiently utilize working 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 working fluids, versus a medium pressure working 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 working fluid vapor and delivers the vapor to the condenserthrough a discharge passage. In some embodiments, the compressormay be a centrifugal compressor. The working fluid vapor delivered by the compressorto the condensermay transfer heat to a cooling fluid (e.g., water or air) in the condenser. The working fluid vapor may condense to a working fluid liquid in the condenserdue to thermal heat transfer with the cooling fluid. The liquid working 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 working 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 working fluid in the evaporatormay undergo a phase change from the liquid working fluid to a working 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 working fluid. The tube bundlein the evaporatorcan include a plurality of tubes and/or a plurality of tube bundles. In any case, the vapor working 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, etc.). 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 working 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 working fluid because of a pressure drop experienced by the liquid working 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 working fluid exiting the condenserdue to 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.

With the foregoing in mind,is a schematic of an embodiment of a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system, such as a centrifugal chiller system. The HVAC&R systemincludes similar elements as those described above. For example, the HVAC&R systemincludes a working fluid circuit(e.g., vapor compression circuit) having a compressor system, a condenser, and expansion valve, and an evaporator. The working fluid circuitmay circulate a working fluid therethrough to enable heat transfer between the working fluid and one or more additional fluids, such as a conditioning fluid, a cooling fluid, another suitable fluid, or any combination thereof.

The HVAC&R systemalso includes a lubricant separation systemconfigured to enable improved separation of mixed working fluid and lubricant within the working fluid circuit. As mentioned above, the compressor systemmay include one or more compressorsand one or more components configured to rotate during operation of the compressor system. The HVAC systemmay therefore be configured to supply a lubricant (e.g., oil) to the compressor system(e.g., to bearings of the compressor system) to facilitate rotation of such rotating components. To this end, the HVAC&R systemmay include a lubricant reservoirconfigured to store lubricant and supply the lubricant to the compressor system. However, during operation of the HVAC&R system, an amount of lubricant supplied to the compressor systemmay become mixed with the working fluid circulated through the working fluid circuitby the compressor system. In some instances, the lubricant mixed with the working fluid may be directed along the working fluid circuittowards other components of the working fluid circuit, such as the evaporator. Indeed, in some applications, lubricant mixed with working fluid may collected within certain components of the working fluid circuit. Accordingly, present embodiments include the lubricant separation systemconfigured to enable improved separation of lubricant and working fluid that has mixed together within the HVAC&R system. In the manner described below, the working fluid and lubricant may be separated from one another and may be separately directed to suitable portions or components of the HVAC&R system.

In the illustrated embodiment, the lubricant separation systemincludes a lubricant separation heat exchangerconfigured to enable separation of lubricant from working fluid that has mixed together within the working fluid circuit(e.g., within the compressor system). Configurations and embodiments of the lubricant separation heat exchangerare described in further detail below. In operation, the lubricant separation heat exchangeris configured to receive a flow of lubricant and working fluid from a component of the working fluid circuit. For example, in the illustrated embodiment, the lubricant separation heat exchangeris configured to receive a mixture of lubricant and working fluid from the evaporatorof the working fluid circuit, as indicated by arrow. The mixture may include lubricant and a portion of liquid working fluid collected within the evaporator.

The lubricant separation heat exchangeris also configured to receive a flow of heated fluid and to place the flow of heated fluid in a heat exchange relationship with the mixture of lubricant and working fluid. The flow of heated fluid may be any suitable heated fluid supplied by any suitable source. For example, the flow of heated fluid may be a flow of heated lubricant supplied by the lubricant reservoir, as indicated by arrow. In some embodiments, the flow of heated lubricant may be directed to the lubricant separation heat exchangerby a pumpof the lubricant reservoir. Additionally or alternatively, the lubricant reservoirmay include a heater(e.g., heating element) configured to heat the lubricant for supply to the lubricant separation heat exchanger, such as during initial startup of the HVAC&R system. The lubricant separation heat exchangermay configured to place the heated lubricant in a heat exchange relationship (e.g., a fluidly separate heat exchange relationship) with the mixture of lubricant and working fluid to enable transfer of heat from the heated lubricant to the mixture of lubricant and working fluid. As a result, liquid working fluid mixed with the lubricant may evaporate and become separated from the lubricant. Thereafter, the evaporated working fluid may be directed from the lubricant separation heat exchangerback to the evaporator, as indicated by arrow, by the lubricant separation system.

The lubricant remaining within the lubricant separation heat exchangerfrom the initial mixture of lubricant and working fluid may be directed to return to the lubricant reservoir. In some embodiments, the separated and/or concentrated lubricant within the lubricant separation heat exchangermay be directed toward an eductor(e.g., jet pump, ejector, vacuum pump), as indicated by arrow(e.g., a conduit), by the lubricant separation system. The eductormay receive the separated and/or concentrated lubricant from the lubricant separation heat exchangeras an inlet or suction fluid. The eductormay also receive a flow of a motive fluid to enable generation of a differential pressure or vacuum within the eductorand thereby cause the eductorto draw the separated and/or concentrated lubricant into the eductorfrom the lubricant separation heat exchanger. In some embodiments, the motive fluid supplied to the eductormay be a high-pressure working fluid gas or vapor (e.g., pressurized fluid) directed to the eductorfrom the compressor system, as indicated by arrow. In some embodiments, the pressurized working fluid gas may be discharged from a discharge port of one of the compressorsof the compressor system. For example, the compressorsmay include a first compressor(e.g., first stage compressor, low stage compressor) and a second compressor(e.g., second stage compressor, high stage compressor) arranged in series (e.g., relative to flow of working fluid through the compressor system), and the pressurized working fluid gas may be directed from a discharge of the first compressorto the eductor. However, in other embodiments, the motive fluid supplied to the eductormay be provided by another portion of the compressor system(e.g., an intermediate stage of a multi-stage compressor) or another suitable source of pressurized fluid.

In the illustrated embodiment, the eductoris configured to direct a mixture of the concentrated lubricant and the high-pressure working fluid gas to the lubricant reservoir. As will be appreciated, the concentrated lubricant and the high-pressure working fluid gas may not readily mix within the eductorand/or the lubricant reservoir. Accordingly, the high-pressure working fluid gas may be directed back to the compressor system(e.g., to the second compressor) to mix with working fluid directed along the working fluid circuit, as indicated by arrow. The working fluid by the lubricant reservoirfrom the eductormay evaporate into working fluid vapor by absorbing heat from the heated lubricant within the lubricant reservoirand may be directed to the compressor system, as indicated by arrow. As will be appreciated, the lubricant reservoiris also configured to receive lubricant from the compressor system, as indicated by arrow for reconditioning (e.g., cooling) and subsequent use to lubricate components of the compressor system, as indicated by arrow. While the present discussion describes return of the concentrated lubricant from the lubricant separation heat exchangerto the lubricant reservoirvia operation of the eductor, it should be appreciated that the lubricant separation systemmay include additional or alternative components to enable flow of the separated lubricant from the lubricant separation heat exchangerto the lubricant reservoir. For example, the lubricant separation systemmay include one or more conduits, valves, pumps, other suitable components, or any combination thereof to enable flow of separated and/or concentrated lubricant from the lubricant separation heat exchangerto the lubricant reservoir.

Turning back to discussion of the operation of the lubricant separation heat exchanger, the heated lubricant directed through the lubricant separation heat exchangeras the heated fluid may decrease in temperature as the heated lubricant transfers heat to the mixture of lubricant and working fluid within the lubricant separation heat exchanger. Thus, in some embodiments, the lubricant separation heat exchangermay additional function as a cooling system for the lubricant within the lubricant reservoir. As a result, certain embodiments of the HVAC&R systemmay not include a separate and/or dedicated cooling system to cool lubricant within the lubricant reservoirthat is received from the compressor system. Additionally or alternatively, the HVAC&R systemmay include a lubricant cooling system that operates with reduced power consumption. The lubricant directed through the lubricant separation heat exchangeras the heated fluid may be discharged by the lubricant separation heat exchangerand be directed from the lubricant separation heat exchangerto the compressor system(e.g., by the lubricant separation system) for use with lubricating components, such as bearings, of the compressor system, as indicated by arrow(e.g., a conduit). That is, the lubricant utilized as the heated fluid within the lubricant separation heat exchangermay not be directed back to the lubricant reservoir, in some embodiments.

In further embodiments, the lubricant separation systemmay utilize additional or alternative fluids as the heated fluid to enable transfer of heat to the mixture of lubricant and working fluid within the lubricant separation heat exchanger. For example, the HVAC&R systemmay include a control system(e.g., controller, automation controller, control board) that includes and/or utilizes a cooling systemconfigured to cool one or more electronic components of the control system.

In some embodiments, the control systemmay include processing circuitry, such as a microprocessor, which may execute software for controlling the components of the HVAC&R system. The processing circuitrymay include multiple microprocessors, one or more “general-purpose” microprocessors, one or more special-purpose microprocessors, and/or one or more application specific integrated circuits (ASICS), or some combination thereof. For example, the processing circuitrymay include one or more reduced instruction set (RISC) processors. The control systemmay also include a memory device(e.g., a memory) that may store information, such as instructions, control software, look up tables, configuration data, etc. The memory devicemay include a volatile memory, such as random access memory (RAM), and/or a nonvolatile memory, such as read-only memory (ROM). The memory devicemay store a variety of information and may be used for various purposes. For example, the memory devicemay store processor-executable instructions including firmware or software for the processing circuitryexecute, such as instructions for controlling components of the HVAC&R system. In some embodiments, the memory deviceis a tangible, non-transitory, machine-readable-medium that may store machine-readable instructions for the processing circuitryto execute. The memory devicemay include ROM, flash memory, a hard drive, or any other suitable optical, magnetic, or solid-state storage medium, or a combination thereof. The memory devicemay store data, instructions, and any other suitable data. Further, the control systemmay include a variable speed drive (VSD), which may be configured to operate one or more of the compressorsat variable speeds, as similarly discussed above.

In some embodiments, the cooling systemmay circulate a cooling fluid (e.g., water, glycol, mixture of water and glycol) and place the cooling fluid in a heat exchange relationship with one or more components of the control system, such as the VSD. In this way, the cooling fluid circulated by the cooling systemmay absorb heat from components (e.g., electrical components) of the control system. As the cooling fluid absorbs heat from components (e.g., electrical components) of the control system, the cooling fluid may become heated. The cooling fluid may therefore be suitable for use as the heated fluid directed through the lubricant separation heat exchanger. Thus, the control system(e.g., cooling system, heated fluid source) may be configured to direct the cooling fluid to the lubricant separation heat exchanger, as indicated by arrow, after the cooling fluid absorbs heat from components of the control system. Within the lubricant separation heat exchanger, the cooling fluid may transfer heat to the mixture of lubricant and working fluid, thereby reducing a temperature of the cooling fluid to recondition (e.g., cool) the cooling fluid for subsequent use within the cooling systemto cool components of the control system. The cooling fluid may therefore be directed from the lubricant separation heat exchangerback to the cooling system, as indicated by arrow.

Additionally or alternatively, the lubricant separation systemmay utilize a flow of the working fluid as the heated fluid to enable transfer of heat to the mixture of lubricant and working fluid within the lubricant separation heat exchanger. For example, as indicated by arrow, a flow of working fluid (e.g., heated working fluid, condensed working fluid) may be directed from the condenser(e.g., heated fluid source) to the lubricant separation heat exchanger. Within the lubricant separation heat exchanger, heat may be transferred from the flow of working fluid to the mixture of lubricant and working fluid (e.g., to vaporize the working fluid within the mixture). In this way, the lubricant separation heat exchangermay operate to subcool and/or further subcool the flow of working fluid utilized as the heated fluid. Thereafter, the flow of working fluid utilized as the heated fluid may be directed back to the working fluid circuit, such as downstream of the condenserand upstream of the expansion valve, as indicated by arrow.

is a schematic axial view of an embodiment of the evaporatorof the working fluid circuitand the lubricant separation heat exchangerof the lubricant separation system, in accordance with an aspect of the present disclosure. As discussed above, the lubricant separation heat exchangeris configured to receive a mixture of lubricant and working fluidfrom the evaporatorand to receive a flow of heated fluid, such as a flow of heated lubricant, to enable transfer of heat from the flow of heated fluid to the mixture of lubricant and working fluid. As heat is transferred to the mixture of lubricant and working fluid, liquid working fluid within the mixture may evaporate and become separated from lubricant within the mixture, which may remain in the liquid phase. In this way, the lubricant may become concentrated and/or separated lubricantthat may be discharged from the lubricant separation heat exchangerand directed toward the lubricant reservoir(e.g., the eductor) for use in lubricating components of the compressor system. Evaporated (e.g., vaporized, separated) working fluidthat is separated from the lubricant may be directed from the lubricant separation heat exchangerback to the evaporator.

In some embodiments, the evaporatormay be a hybrid falling film evaporator. That is, the evaporatormay include a shell(e.g., a housing) with a falling film sectionand a flooded sectiondisposed therein. The falling film sectionmay be disposed vertically above the flooded sectionwith respect to a direction of gravity. The falling film sectionand the flooded sectionmay each include a respective plurality of tubes extending therethrough and configured to circulate a conditioning fluid. As will be appreciated, liquid working fluid within the shellof the evaporatormay collect within the flooded sectionof the evaporator. Lubricant within the shellof the evaporator, such as lubricant that initially enters the flow of working fluid within the compressor system, may also collect within the flooded section. As a result, a mixture of liquid working fluid and lubricant may collect and/or accumulate within the flooded sectionof the evaporator. Accordingly, the lubricant separation systemmay include a first conduit(e.g., inlet conduit, first inlet conduit) extending from the flooded section(e.g., the shell) to the lubricant separation heat exchanger, where the first conduitis configured to direct the mixture of lubricant and working fluidfrom the evaporatorto the lubricant separation heat exchanger, such as via force of gravity. The lubricant separation systemmay also include a first outlet conduitconfigured to discharge the concentrated and/or separated lubricantfrom the lubricant separation heat exchangerand direct the separated lubricanttoward the lubricant reservoirand/or the eductor. Further, the lubricant separation systemmay include a second outlet conduitconfigured to direct the evaporated and/or separated working fluidfrom the lubricant separation heat exchangerback to the evaporator. For example, the second outlet conduitmay extend from a top portion of the lubricant separation heat exchangerto the shellat and/or adjacent the falling film sectionof the evaporator.

To enable heat exchange between the mixture of lubricant and working fluidand the flow of heated fluid, the lubricant separation heat exchangermay include a heat transfer apparatus(e.g., heat transfer device, heat transfer block, heat transfer assembly) configured to place the mixture of lubricant and working fluidand the flow of heated fluidin a heat exchange relationship with one another. As discussed in further detail below, the heat transfer apparatusmay also be positioned within a shellof the lubricant separation heat exchangerin a manner that maintains fluid separation of the mixture of lubricant and working fluidfrom the flow of heated fluidwithin the lubricant separation heat exchanger. As also described further below, the mixture of lubricant and working fluiddirected into the shellby the first conduitmay flow through and/or across the heat transfer apparatustoward the first outlet conduit.

In some embodiments, the lubricant separation heat exchangermay include a first header(e.g., first manifold) configured to direct the flow of heated fluidinto the heat transfer apparatusand a second header(e.g., second manifold) configured to receive the flow of heated fluidfrom the heat transfer apparatusand to discharge the flow of heated fluidfrom the lubricant separation heat exchanger. In some embodiments, the first conduit, the first outlet conduit, the heat transfer apparatus, the first header, and/or the second headermay be arranged such that the mixture of lubricant and working fluidand the flow of heated fluidare directed through the heat transfer apparatusin a counterflow arrangement. In this way, heat transfer between the mixture of lubricant and working fluidand the flow of heated fluidmay be improved, thereby increasing separation of working fluid from lubricant within the lubricant separation heat exchanger.

is a cross-sectional schematic axial view of an embodiment of the lubricant separation heat exchangerof the lubricant separation system, in accordance with an aspect of the present disclosure. As mentioned above, the lubricant separation heat exchangerincludes the heat transfer apparatusdisposed within the shellof the lubricant separation heat exchanger. In the illustrated embodiment, the heat transfer apparatusincludes a block structuredefining a plurality of channelsextending through the block structure. The plurality of channelsmay extend serially or sequentially from a first sideof the block structureto a second sideof the block structure. The plurality of channelsmay therefore define a flow path from the first sideto the second sideof the block structure. To define the plurality of channels, the block structureincludes a plurality of extensions(e.g., protrusions, vertical extensions, projections, legs, etc.) extending (e.g., vertically extending) from a base portionof the block structure. In some embodiments, the plurality of channelsmay extend between corresponding, adjacent extensionsto define a serpentine flow path from the first sideto the second sideof the block structure, as shown in.

The block structuremay be positioned within the shellof the lubricant separation heat exchangerto separate a first cavity(e.g., inlet portion, intake cavity) within the shellfrom a second cavity(e.g., outlet portion, discharge cavity) within the shell. During operation of the lubricant separation heat exchanger, the mixture of lubricant and working fluidmay be directed into the shellvia an inletof the lubricant separation heat exchangerthat may be fluidly coupled to the first conduit. In particular, the mixture of lubricant and working fluidmay be directed from the inletinto the first cavity. From the first cavity, the mixture of lubricant and working fluidmay flow through the plurality of channelsfrom the first sideof the block structureto the second sideof the block structure. Indeed, lubricant separation heat exchangermay be configured to block flow of the mixture of lubricant and working fluiddirectly from the first cavityto the second cavitywithout flowing through the plurality of channels. For example, the lubricant separation heat exchangermay include one or more seals (e.g., sealing elements, cushions, barrier elements, sealing members) configured to block the mixture of lubricant and working fluidfrom flowing around the block structure, such as between the block structureand the shell. In the illustrated embodiment, the lubricant separation heat exchangerincludes a base sealpositioned between the shelland the base portionof the block structureto block flow of the mixture of lubricant and working fluidtherebetween. The lubricant separation heat exchangermay include additional or alternative seals, as described below with reference to.

The heat transfer apparatusfurther includes a plurality of tubespositioned within and extending through the plurality of channels. For example, the plurality of tubesmay also extend through the plurality of channelsin a serpentine pattern. In the illustrated embodiment, the plurality of tubesis vertically arrayed within the plurality of channels. Each tubeis configured to direct the heated fluid therethrough. For example, each tubemay include a respective inletfluidly coupled to the first headerand a respective outletfluidly coupled to the second header.

During operation of the lubricant separation heat exchanger, the mixture of lubricant and working fluidmay flow from the first cavitywithin the shell, through the plurality of channels, and to the second cavitywithin the shell, while the flow of heated fluidmay flow through the plurality of tubesextending within the plurality of channels. As the mixture of lubricant and working fluidand the flow of heated fluidare directed through the heat transfer apparatusin this manner, heat may be transferred from the flow of heated fluidto the mixture of lubricant and working fluid, thereby causing liquid working fluid within the mixtureto evaporate. As indicated by arrows, evaporated working fluidmay separate from the lubricant within the mixtureand rise (e.g., flow upwardly) within the plurality of channelstoward an outletof the lubricant separation heat exchanger(e.g., shell). As a result, the mixture of lubricant and working fluidmay be separated into the evaporated working fluidand separated lubricant, and the separated lubricantmay collect and/or accumulate within the second cavityof the shell. The separated lubricantmay flow from the second cavitythrough an outletof the shell, which may be fluidly coupled to the first outlet conduit, to be discharged from the lubricant separation heat exchanger.

The components of the lubricant separation heat exchanger(e.g., the heat transfer apparatus) may be formed from any suitable material and utilizing any suitable processes. For example, the block structuremay be formed from a polymer (e.g., plastic) and/or a metallic material (e.g., aluminum) and may be formed via injection molding, machining, cutting, additive manufacturing (e.g., three-dimensional printing), and/or another suitable process. Similarly, seals (e.g., base seal) disposed between the block structureand the shellmay be formed from any suitable material, such as plastic, metal, a compressible material, foam, a polymer, and/or another suitable material. Indeed, the components of the lubricant separation heat exchangerdescribed herein may be formed from any suitable material compatible with the working fluid and the lubricant utilized by the HVAC&R system.

a cross-sectional schematic top view of an embodiment of the lubricant separation heat exchangerof the lubricant separation system, in accordance with an aspect of the present disclosure. The illustrated embodiment includes similar elements and element numbers as the embodiment described above with reference to. For example, the lubricant separation heat exchangerincludes the heat transfer apparatushaving the block structureand the plurality of tubesdisposed within the shellof the lubricant separation heat exchanger. The plurality of channelsdefined by the plurality of extensionsof the block structurecooperatively form a serpentine flow paththrough the block structure(e.g., from the first cavityto the second cavitywithin the shell). Additionally, the plurality of tubesextend through the shelland along the serpentine flow path. Thus, the flow of heated fluidmay be directed through the plurality of tubesto transfer heat to the mixture of lubricant and working fluidwithin the serpentine flow pathto enable separation of the mixtureinto evaporated working fluidand concentrated lubricant.

The illustrated embodiment also includes additional sealspositioned within the shellto separate the first cavityfrom the second cavity. That is, similar to the base seal, the additional sealsare configured to block flow of the mixture of lubricant and working fluidfrom the first cavitydirectly to the second cavitywithout flowing along the serpentine flow path. The additional sealsmay be incorporated in the lubricant separation heat exchangerin conjunction with the base sealdiscussed above. The additional sealsinclude a first end sealand a second end sealpositioned at respective longitudinal endsof the shell(e.g., the block structure), relative to a longitudinal axisof the lubricant separation heat exchanger. For example, the first end sealmay be disposed between the block structureand a first end plateof the shell, and the second end sealmay be disposed between the block structureand a second end plateof the shell. During assembly and/or manufacturing of the lubricant separation heat exchanger, the additional sealsmay be captured between the block structureand the respective end plates,, and the end plates,may be secured (e.g., welded, bolted, fastened) to a main bodyof the shell. In this way, the additional sealsmay be secured (e.g., captured, wedged) between the block structureand the shellto create a sealing engagement (e.g., a fluid seal, a fluidic barrier) that may block direct flow of the mixture of lubricant and working fluidfrom the first cavityto the second cavitywithout flowing through the serpentine flow pathdefined by the plurality of channels.

is a cross-sectional schematic axial view of an embodiment of the lubricant separation heat exchangerof the lubricant separation system, in accordance with an aspect of the present disclosure. As similarly described above, the lubricant separation heat exchangerincludes the shell, the inletconfigured to receive the mixture of lubricant and working fluidfrom the evaporator, the outletconfigured to discharge the concentrated lubricant, and the outletconfigured to discharge the evaporated working fluid.

The illustrated embodiment also includes an alternative embodiment of the heat transfer apparatus, referred to herein as a heat transfer apparatus. In particular, the heat transfer apparatusincludes an alternative embodiment of the block structureincluding the base portionand the plurality of extensionsextending (e.g., vertically extending) from the base portionto define the plurality of channelsdiscussed above. The plurality of extensionsincludes a plurality of ports(e.g., passages, flow paths, cavities) formed therein. The plurality of portsis configured to circulate the flow of heated fluidtherethrough, such that the flow of heated fluidmay flow internally through the block structure(e.g., internally through the plurality of extensions). Accordingly, the heat transfer apparatusdoes not include the plurality of tubesdiscussed above.

The plurality of portsextending internally through the plurality of extensionsmay define one or more flow paths (e.g., serpentine flow paths). For example, each portmay be serially connected with one another, such that the plurality of portsdefine a single flow path for the flow of heated fluidthrough the heat transfer apparatus. Alternatively, the plurality of portsmay define multiple flow paths (e.g., multiple serpentine flow paths) configured to direct portions of the flow of heated fluidthrough the heat transfer apparatus. For example, the plurality of portsmay define multiple flow paths arrayed vertically along the plurality of extensions. In such embodiments, each flow path may be fluidly coupled to the first headerconfigured to supply the flow of heated fluidto the lubricant separation heat exchanger, and each flow path may be fluidly coupled to the second headerconfigured to discharge the flow of heated fluidfrom the lubricant separation heat exchanger.

The block structureof the heat transfer apparatusmay be similar positioned within the shellof the lubricant separation heat exchangerto separate the first cavityfrom the second cavitywithin the shell. In some embodiments, the heat transfer apparatusmay include seals (e.g., base seal, additional seals) similar to those discussed above to separate the first cavityfrom the second cavityand block the mixture of lubricant and working fluidfrom flowing directly from the first cavityto the second cavity(e.g., bypassing flow through the plurality of channels). Additionally or alternatively, the base portionof the block structuremay include a geometry (e.g., curvature) corresponding to (e.g., matching) a geometry of the shell, as shown, to enable a fluidic seal between the block structureand the shell.

In the illustrated embodiment, the block structurealso includes a plurality of passagesformed within the plurality of extensions. In particular, each extensionmay include one of the passagesformed therein, such as at a base of the respective extension(e.g., adjacent the base portionof the block structure). The passagesare configured to enable flow of the mixture of lubricant and working fluidbetween adjacent channelsdefined by the plurality of extensions. Thus, the passagesare configured to direct flow of the mixture of lubricant and working fluidthrough the heat transfer apparatus(e.g., from the first cavityto the second cavity) via the plurality of channels. In some embodiments, the respective passagesof adjacent extensionsmay be formed at opposite ends (e.g., opposite longitudinal ends, relative to longitudinal axis) of the block structureand/or the shell). In this way, the plurality of channelsand the plurality of passagesmay cooperatively define a serpentine flow path configured to direct the mixture of lubricant and working fluidthrough the heat transfer apparatus. As the mixture of lubricant and working fluidthrough the plurality of channelsand the plurality of passages, the mixturemay absorb heat from the flow of heated fluiddirected through the plurality of portsto cause liquid working fluid within the mixtureto evaporate and generate the evaporated working fluidand the separated lubricantas similarly described above.

is a cross-sectional schematic top view of another embodiment of the lubricant separation heat exchangerof the lubricant separation system, in accordance with an aspect of the present disclosure. As similarly discussed above, the lubricant separation heat exchangeris configured to receive the mixture of lubricant and working fluidfrom the evaporatorand the flow of heated fluid(e.g., from the lubricant reservoir) and place the mixturein a heat transfer relationship with the flow of heated fluidto enable separation of the mixtureinto the evaporated working fluidand the concentrated lubricant.