Vapor compression system and controller for providing compressor cooling

Abstract

The vapor compression system includes a primary circuit and a secondary circuit. The primary circuit includes a dynamic compressor operable to compress refrigerant, a condenser fluidly connected with the dynamic compressor, a first expansion device fluidly connected with the condenser, and an evaporator fluidly connected with the first expansion device and the dynamic compressor. A dynamic compressor includes a housing, a shaft supported in the housing by a bearing, an impeller connected to the shaft, a motor operatively connected to the shaft to drive rotation of the shaft, and a driver operable to control the motor. The secondary circuit includes a second expansion device fluidly connected with the condenser, a heat exchanger fluidly connected with the second expansion device, the condenser, and the dynamic compressor, and a supply conduit fluidly connected between the heat exchanger and the dynamic compressor to provide a flow of refrigerant to the bearing.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. patent application No. 17 / 930,807, filed on September 9, 2022, the entire contents of which are incorporated by reference in their entirety. Technical Field

[0003] The field of the present disclosure relates generally to heating, ventilation, and air conditioning (HVAC) systems, and more particularly to control systems for HVAC systems. Background Art

[0004] Dynamic compressors, including centrifugal compressors, are commonly used in process industries and heating, ventilation and air conditioning (HVAC) systems. The compressor is usually connected to a motor via a shaft that supports multiple compression stages. The driver controls the motor to rotate the compression stages at selected speeds and load conditions, thereby compressing the refrigerant to a specified demand. The motor speed and load can be controlled to operate the compressor under a wide range of operating conditions.

[0005] During operation, the drive, motor and compressor bearings can reach high temperatures which, if not addressed, can increase the risk of mechanical failure due to overheating. Many existing cooling systems divert low temperature refrigerant from the main flow path to the components that need cooling. However, using liquid refrigerant for cooling creates the opportunity for liquid to enter the bearings or high-speed impellers, thereby reducing the performance and life of the compressor. Therefore, there is a need for a compressor cooling system that uses only gaseous refrigerant as the cooling fluid.

[0006] This section is intended to introduce the reader to various aspects of the technology that may be related to various aspects of the present disclosure, which are described and / or claimed below. It is believed that this discussion is helpful in providing the reader with background information to better understand the various aspects of the present disclosure. Therefore, it should be understood that these statements should be understood from this perspective, and not as an admission of prior art. Summary of the invention

[0007] One aspect of the present disclosure relates to a vapor compression system including a primary circuit and a secondary circuit. The primary circuit includes a dynamic compressor operable to compress a refrigerant, a condenser fluidly connected to the dynamic compressor, a first expansion device fluidly connected to the condenser, and an evaporator fluidly connected to the first expansion device and the dynamic compressor. The dynamic compressor includes a housing, a shaft supported in the housing by bearings, an impeller connected to the shaft, a motor operatively connected to the shaft to drive the shaft to rotate, and a driver operable to control the motor. The secondary circuit includes a second expansion device fluidly connected to the condenser, a heat exchanger fluidly connected to the second expansion device, the condenser, and the dynamic compressor, and a supply conduit fluidly connected between the heat exchanger and the dynamic compressor to provide a refrigerant flow to the bearing.

[0008] Another aspect of the present disclosure relates to a controller for a compressor system. The compressor system includes a dynamic compressor and a cooling device, and the cooling device includes a heat exchanger and a supply conduit fluidly connected between the heat exchanger and the dynamic compressor. The controller includes a processor and a memory, the memory storing instructions that program the processor to operate the dynamic compressor to compress refrigerant, operate the cooling device to provide a refrigerant flow to a bearing of the dynamic compressor through the supply conduit, determine whether a condition is met, and adjust the position of a valve in fluid communication between the dynamic compressor and the cooling device when the condition is met.

[0009] Another aspect of the present disclosure relates to a compressor system, comprising a dynamic compressor operable to compress a refrigerant and a cooling device. The dynamic compressor comprises a housing, a shaft supported in the housing by a bearing, and an impeller connected to the shaft. The cooling device comprises a heat exchanger fluidly connected to the dynamic compressor, a supply conduit fluidly connected between the heat exchanger and the dynamic compressor to provide a refrigerant flow to the bearing, a valve fluidly connected to the supply conduit and selectively positionable to allow the refrigerant to flow therethrough, and a controller operable to control the valve.

[0010] There are various improvements to the features associated with the above-mentioned aspects of the present disclosure. Other features may also be included in the above-mentioned aspects of the present disclosure. These improvements and additional features may exist alone or in any combination. For example, the various features discussed below with respect to any illustrated embodiment of the present disclosure may be incorporated into any of the above-mentioned aspects of the present disclosure alone or in any combination. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a perspective view of a dynamic compressor according to one embodiment.

[0012] Figure 2 It is taken along line 2-2 Figure 1Cross-sectional view of a dynamic compressor with the external duct removed.

[0013] Figure 3 is used for Figure 1 and Figure 2 A block diagram of a control system for a dynamic compressor as shown in;

[0014] Figure 4 It can be installed Figure 1 and Figure 2 A schematic diagram of a first example vapor compression system with a dynamic compressor shown in;

[0015] Figure 5 It can be installed Figure 1 and Figure 2 A schematic diagram of a second example vapor compression system with a dynamic compressor shown in;

[0016] Figure 6 It can be installed Figure 1 and Figure 2 A schematic diagram of a third example vapor compression system of a dynamic compressor shown in;

[0017] Figure 7 yes Figure 6 A schematic diagram of an alternative embodiment of a third example vapor compression system is shown.

[0018] Figure 8 It can be installed Figure 1 and Figure 2 A schematic diagram of a fourth example vapor compression system of a dynamic compressor shown in;

[0019] Fig. 9 It can be installed Figure 1 and Figure 2 A schematic diagram of a fifth example vapor compression system of a dynamic compressor shown in;

[0020] Fig.10 is an example control algorithm for controlling a first refrigerant flow to a bearing assembly.

[0021] Fig.11 is a first example control algorithm for controlling the second refrigerant flow to the motor.

[0022] Fig.12 is a second example control algorithm for controlling a second refrigerant flow to the driver.

[0023] Fig.13 is a first example control algorithm for controlling the flow of the tertiary refrigerant to the motor.

[0024] Fig.14is a second example control algorithm for controlling the flow of the tertiary refrigerant to the driver.

[0025] Fig.15 yes Figures 10 to 14 A flow chart of an example control algorithm is shown.

[0026] Corresponding reference numerals indicate corresponding parts throughout the drawings. DETAILED DESCRIPTION

[0027] For simplicity, examples will be described for a centrifugal compressor. However, the methods and systems described herein can be applied to any suitable compressor. The bearings, motors, and drivers of a dynamic compressor can be cooled using steam injection by diverting a portion of the main flow through a supplemental loop with a heat exchanger or flash tank. The gaseous refrigerant leaving the heat exchanger or flash tank can be selectively provided to the bearings, motors, or drivers based on the measured and desired temperatures of these components.

[0028] Reference Figure 1 The two-stage refrigerant compressor is generally indicated at 100. The compressor 100 is operable to compress a working fluid (e.g., a refrigerant), and the compressor 100 includes a compressor housing 102, the compressor housing 102 forming at least one sealed cavity, and each stage of compression of the refrigerant is completed in the sealed cavity. The compressor 100 includes: a first refrigerant inlet 110, which is used to introduce refrigerant vapor into the first compressor stage ( Figure 1 a first refrigerant outlet 114; a refrigerant transfer conduit 112 for transferring the compressed refrigerant from the first compressor stage to the second compressor stage; a second refrigerant inlet 118 for introducing refrigerant vapor into the second compressor stage ( Figure 1 The refrigerant delivery conduit 112 is operatively connected to the first refrigerant outlet 114 and the second refrigerant inlet 118 at opposite ends, respectively. The refrigerant delivery conduit 112 also includes a port 122 for adding or removing flow between the first compressor stage and the second compressor stage. The second refrigerant outlet 120 delivers the compressed refrigerant from the second compressor stage to a cooling system including the compressor 100.

[0029] Reference Figure 2, the compressor housing 102 encloses a first compressor stage 124 and a second compressor stage 126 located at opposite ends of the compressor 100. The first compressor stage 124 includes a first compression mechanism 106, which is configured to add kinetic energy to the refrigerant entering via the first refrigerant inlet 110. In some embodiments, the first compression mechanism 106 is an impeller. The kinetic energy imparted to the refrigerant by the first compression mechanism 106 is converted into an increased refrigerant pressure because the refrigerant velocity is slowed down when the refrigerant is transmitted to the sealed cavity (e.g., diffuser) formed in the volute 132. The first compressor stage 124 also includes a first variable inlet guide vane (VIGV) 134 disposed upstream of the first compression mechanism 106 in the first refrigerant inlet 110. The first variable inlet guide vane 134 includes a plurality of vanes, the positions of which can be controlled to introduce pre-vortex into the gaseous refrigerant entering the first refrigerant inlet 110.

[0030] Similarly, the second compressor stage 126 includes a second compression mechanism 116 configured to add kinetic energy to the refrigerant transmitted from the first compressor stage 124 and entering via the second refrigerant inlet 118. In some embodiments, the second compression mechanism 116 is an impeller. The kinetic energy imparted to the refrigerant by the second compression mechanism 116 is converted into increased refrigerant pressure because the refrigerant velocity is slowed as the refrigerant is transmitted to the sealed cavity (e.g., diffuser) formed within the volute 132. The compressed refrigerant is discharged via the second refrigerant outlet 120 ( Figure 2 1 (not shown) exits the second compressor stage 126. The second compressor stage 126 also includes a second variable inlet guide vane (VIGV) 136 disposed upstream of the second compression mechanism 116 in the second refrigerant inlet 118. The second variable inlet guide vane 136 includes a plurality of vanes whose positions can be controlled to introduce pre-swirl into the gaseous refrigerant entering the second refrigerant inlet 118.

[0031] The first compression mechanism 106 and the second compression mechanism 116 are connected at opposite ends of the shaft 104. The shaft 104 is operatively connected to a motor 108 positioned between the first compression mechanism 106 and the second compression mechanism 116 so that the first compression mechanism 106 and the second compression mechanism 116 rotate at a selected rotational speed to compress the refrigerant to exit the second refrigerant outlet 120 ( Figure 2100). Any suitable motor, including but not limited to an electric motor, may be incorporated into the compressor 100. The motor 108 may include a motor temperature sensor (not shown) operable to determine the temperature of the motor. The motor temperature sensor may be a thermocouple, a thermistor, a resistance temperature detector (RTD), or any other suitable sensor. The shaft 104 is rotatably supported by a gas foil bearing assembly 200 positioned within a sleeve 252 of each bearing housing 250 / 250a, as described in further detail below. Each bearing housing 250 / 250a includes a mounting structure for connecting the corresponding bearing housing 250 / 250a to the compressor housing 102.

[0032] Figure 3 An example embodiment of a system 600 including a dynamic compressor 100 is shown. The system 600 can be any suitable system in which the dynamic compressor 100 can be installed. The compressor 100 includes a compressor housing 102, a compression mechanism 607, a motor 108, a speed sensor 617, a pressure sensor 609, and a controller 610. In the present embodiment, the dynamic compressor 100 is a two-stage centrifugal compressor, and the compression mechanism 607 is an impeller in each stage. In other embodiments, the dynamic compressor 100 can be an axial flow compressor, and the compression mechanism 607 can be an axial flow rotor. The speed sensor 617 measures the rotational speed of the compressor 100, and the pressure sensor 609 measures the pressure at various points along the compressor flow path, including the pressure at the refrigerant inlet and the refrigerant outlet. Additional sensors can be installed in the compressor 100 to provide data about its operation, including but not limited to temperature sensors, flow sensors, current sensors 608, voltage sensors, rotation rate sensors, and any other suitable sensors. The compressor 100 is not limited to the specific configuration in the system 600 and can be used with Figure 1 and Figure 2 The compressor 100 described in is similarly configured or may be configured differently. The system 600 also includes an unloading device 601 , a variable frequency drive 616 operable to control the motor 108 , and a user interface 615 .

[0033] The controller 610 is operatively connected to the compressor 100 to control the operation of the compressor 100 based in part on the above-mentioned measured parameters. The controller 610 includes a processor 611, a memory 612, and an unloading interface 614. The memory 612 stores instructions for programming the processor 611 to determine whether the bearing assembly 200, the motor 108, and / or the driver 616 need cooling, which will be discussed in more detail below. The system 600 includes an interface for connecting the controller 610 to the driver 616 and a motor interface 613 for connecting the driver 616 to the motor 108. In some embodiments, the driver 616 operates under the control of the controller 610. In another embodiment, the driver 616 is part of the controller 610. The driver 616 may include a driver temperature sensor (not shown), which is operable to determine the temperature of the driver. The driver temperature sensor may be a thermocouple, a thermistor, a resistance temperature detector (RTD), or any other suitable sensor. The system 600 also includes an unloading interface 614, which is used to connect the controller 610 to the unloading device 601.

[0034] The controller 610 is operatively coupled to the unloading device 601 via the unloading interface 614, which removes and / or reduces the load on the compressor 100 during startup and shutdown procedures, during detection of surge events, and when otherwise directed by the controller 610. In the example embodiment, the unloading device 601 is a variable inlet guide vane (VIGV) ( Figure 2 ). In other embodiments, the unloading device 601 may be a variable diffuser, a bypass valve, or any suitable device or combination of devices to reduce the load on the compressor 100. The unloading device 601 may additionally or alternatively be used as a loading device to increase the load on the compressor 100. The controller 610 is configured to control at least one operating parameter of the unloading device 601, such as the position of each VIGV.

[0035] The system 600 also includes a user interface 615 configured to output (e.g., display) and / or receive information associated with the system 600 (e.g., information from a user). In some embodiments, the user interface 615 is configured to receive enable and / or disable input from a user to enable and disable (i.e., turn on and off) or otherwise activate operation of the system 600. Additionally, in some embodiments, the user interface 615 is configured to output information associated with one or more operating features of the system 600, including, for example, but not limited to, warning indications such as severity alarms, occurrence alarms, fault alarms, motor speed alarms, and any other suitable information.

[0036] The user interface 615 may include any suitable input devices and output devices that enable the user interface 615 to function as described herein. For example, the user interface 615 may include input devices including, but not limited to, a keyboard, a mouse, a touch screen, a joystick, a throttle, a button, a switch, and / or other input devices. In addition, the user interface 615 may include output devices including, for example, but not limited to, a display (e.g., a liquid crystal display (LCD) or an organic light emitting diode (OLED) display), a speaker, an indicator light, an instrument, and / or other output devices. In addition, the user interface 615 may be part of a different component, such as a system controller (not shown). Other embodiments do not include the user interface 615.

[0037] The controller 610 is generally configured to control the operation of the dynamic compressor 100. The controller 610 controls the operation through programming and instructions from another device or controller, or is integrated with the system 600 through a system controller. In some embodiments, for example, the controller 610 receives user inputs from a user interface 615 and controls one or more components of the system 600 in response to these user inputs. For example, the controller 610 can control the motor 108 based on the user input received from the user interface 615. In some embodiments, the system 600 can be controlled by a remote control interface. For example, the system 600 can include a communication interface (not shown) configured to connect to a wireless control interface to enable remote control and activation of the system 600. The wireless control interface can be implemented on a portable computing device, such as a tablet or a smart phone.

[0038] The controller 610 may generally include any suitable computer and / or other processing unit, including any suitable combination of computers, processing units, and / or the like that may be communicatively coupled to one another and may operate independently or in association with one another (e.g., the controller 610 may form all or part of a controller network). The controller 610 may include one or more modules or devices, one or more of which may be packaged within the system 600, or may be located remotely from the system 600. The controller 610 may be part of the compressor 100, or may be independent and may be part of a system controller in an HVAC system. The controller 610 and / or components of the controller 610 may be integrated or incorporated within other components of the system 600. The controller 610 may include one or more processors 611 and associated storage devices 612 configured to perform various computer-implemented functions (e.g., perform the calculations, determinations, and functions disclosed herein).

[0039] As used herein, the term "processor" refers not only to integrated circuits, but also to controllers, microcontrollers, microcomputers, programmable logic controllers (PLCs), application-specific integrated circuits, and other programmable circuits. In addition, the storage device 612 of the controller 610 can generally be a storage element or include a storage element, which includes but is not limited to a computer-readable medium (e.g., a random access memory (RAM)), a computer-readable non-volatile medium (e.g., a flash memory), a floppy disk, a read-only compact disk memory (CD-ROM), a magneto-optical disk (MOD), a digital versatile disk (DVD), and / or other suitable storage elements. Such a storage device 612 can generally be configured to store appropriate computer-readable instructions, which configure the controller 610 when executed by the processor 611 or cause the controller 410 to perform various functions described herein, including but not limited to controlling the system 600, controlling the operation of the motor 108, receiving input from the user interface 615, providing output to an operator via the user interface 615, controlling the unloading device 601, and / or various other suitable computer-implemented functions.

[0040] Figure 4 It can be installed Figure 1 and Figure 2 Schematic diagram of a first example vapor compression system 700 with a dynamic compressor 100. The system 700 shown in System 4 has a single, closed refrigerant circuit 310, which includes a compressor 100, a condenser 320, a first expansion device 330, and an evaporator 340. In another embodiment (not shown), the system 700 may include multiple refrigerant circuits to accommodate multiple compressors 100. The refrigerant enters the dynamic compressor 100 at a first refrigerant inlet 110 as a low pressure, low temperature gas. The dynamic compressor 100 adds kinetic energy to the refrigerant and converts the kinetic energy into a pressure rise, and the refrigerant leaves the dynamic compressor 100 at a second refrigerant outlet 120 as a high pressure, high temperature gas. The refrigerant enters the condenser 320, which is fluidly connected to the second compressor 100, and the heat Q 出 is removed to convert the refrigerant gas into a high-pressure, high-temperature liquid.

[0041] The condenser 320 is fluidly connected to a first expansion device 330, which reduces the pressure of the refrigerant. In some embodiments, the pressure can be reduced until the current temperature of the liquid refrigerant becomes the boiling temperature at the pressure, and the refrigerant becomes a two-phase mixture as some of the liquid refrigerant boils and turns into a gas. The first expansion device 330 can be a fixed orifice, a thermal expansion valve, an electronic expansion valve, or any type of expansion device that allows the vapor compression system 700 to function as described herein. The first expansion device 330 is fluidly connected to an evaporator 340, which receives a low pressure, low temperature liquid refrigerant or a two-phase mixture of liquid refrigerant and gas refrigerant at its inlet. In the evaporator 340, the refrigerant absorbs heat Q 进 The evaporator 340 is fluidly connected to the compressor 100 and the cycle begins again.

[0042] Figure 5 It can be installed Figure 1 and Figure 2 Schematic diagram of a second example vapor compression system 800 of a dynamic compressor 100. The system 800 has a primary refrigerant circuit 410, which includes the dynamic compressor 100, the condenser 320, the first stream 492 of the heat exchanger 490, the first expansion device 330, and the evaporator 340. The system 800 also has a secondary refrigerant circuit 460, which is fluidly connected to a portion of the primary refrigerant circuit 410 and is controlled by an economizer valve 470, which will be described in further detail herein.

[0043] The secondary refrigerant circuit 460 includes a second expansion device 480, a second flow 494 of a heat exchanger 490, an economizer valve 470, a second compressor stage 126 ( Figure 2 ) and condenser 320. Figure 5 In the embodiment illustrated in , the components of the secondary refrigerant circuit 460 are fluidly connected in the order in which the components are listed, wherein the condenser 320 is also coupled to the second expansion device 480 to close the secondary refrigerant circuit 460 .

[0044] The economizer valve 470 is controlled by the controller 610 to be fully open, partially open, or fully closed, and the state of the economizer valve 470 determines whether the refrigerant will flow through the secondary refrigerant loop 460. That is, when the economizer valve 470 is fully closed, all the refrigerant will flow through the primary refrigerant loop 410, and the system 800 will operate at the same temperature as the primary refrigerant loop 410. Figure 4800 operates in substantially the same manner as the system 700 illustrated in . When the economizer valve 470 is open, the liquid refrigerant leaving the condenser 320 is split into two streams, with the majority of the refrigerant flowing through the primary refrigerant loop 410 and the remainder of the refrigerant being diverted through the secondary refrigerant loop 460. The economizer valve 470 may be a solenoid valve, an electronic expansion valve, or any type of valve that allows the system 800 to function as described herein.

[0045] When the economizer valve 470 is open, the condenser 320 is fluidly connected to the second expansion device 480, which reduces the pressure of the liquid economizer stream until the current temperature of the liquid refrigerant becomes the boiling temperature at that pressure. When some of the liquid refrigerant boils and turns into a gas as it enters the heat exchanger 490, the refrigerant in the secondary refrigerant loop becomes a two-phase mixture. The second expansion device can be sized and selected to divert a specific amount of refrigerant through the secondary refrigerant loop 460 when the economizer valve 470 is open, the specific amount being, for example, 0% to 20% of the total mass flow, or any amount of refrigerant flow that allows the system 800 to function as described herein.

[0046] In some embodiments, the second expansion device 480 is a thermal expansion valve (TXV) that regulates the amount of refrigerant flowing through the secondary refrigerant loop 460 based on the heat load of the heat exchanger 490. The TXV works in conjunction with a ball 496 located downstream of the second stream 494 of the heat exchanger 490. The membrane inside the TXV is able to move to balance the refrigerant pressure inside the ball with the refrigerant pressure upstream of the heat exchanger 490. The movement of the membrane is coupled to a needle that sets the valve position, thereby controlling the amount of refrigerant flowing through the secondary refrigerant loop 460. In another embodiment, the second expansion device 480 can also be a fixed orifice, an electronic expansion valve, or any type of expansion device that allows the system 800 to function as described herein.

[0047] The refrigerant leaves the second expansion device 480 and enters the second stream 494 of the heat exchanger 490 as a low-pressure liquid or two-phase mixture. The second stream 494 is in thermal communication with the first stream 492, which carries the high-pressure liquid refrigerant from the condenser 320 in the primary refrigerant circuit 410. The thermal contact between the two streams 492, 494 cools the refrigerant in the first stream 492 and warms the refrigerant in the second stream 494, causing it to boil. The cooled refrigerant in the first stream 492 leaves the heat exchanger 490 as a lower temperature, high-pressure liquid, and the boiling refrigerant in the second stream 494 leaves the heat exchanger 490 as a low-temperature, medium-pressure gas. The heat exchanger 490 can be a counterflow heat exchanger, a crossflow heat exchanger, a parallel flow heat exchanger, a shell and tube heat exchanger, a mixing chamber, or any type of heat exchanger that allows the system 800 to function as described herein. In another embodiment, a flash tank may be used instead of or in addition to heat exchanger 490. Such an embodiment is further illustrated and described below.

[0048] The low temperature, medium pressure gas of the second stream 494 exiting the heat exchanger 490 then flows through the economizer line 465 and is injected into the refrigerant transfer conduit 112 ( Figure 2 ) to mix with the refrigerant flow of the primary refrigerant loop 410 before it reaches the second compressor stage 126. The primary refrigerant loop 410 and the secondary refrigerant loop 460 converge at the second compressor stage 126 and diverge again after the refrigerant leaves the condenser 320.

[0049] Figure 6 It can be installed Figure 1 and Figure 2 A schematic diagram of a third example vapor compression system 900 of a dynamic compressor 100 is shown. Figure 5 In addition to all of the components shown and described with respect to the second example vapor compression system 800, the system 900 also includes a cooling device 560 that forms part of a secondary refrigerant loop 460. The cooling device 560 includes a heat exchanger 490 and a first supply conduit 565 fluidly connected between the heat exchanger 490 and the dynamic compressor 100. The secondary refrigerant loop 460 is split into an economizer conduit 465 and a first supply conduit 565 downstream of the heat exchanger 490. A portion of the refrigerant flow in the secondary refrigerant loop 460 flows through the economizer conduit 465, as described above with respect to the second example vapor compression system 800, and the remaining portion of the refrigerant flow flows through the first supply conduit 565 to provide a first refrigerant flow to at least one bearing assembly 200 of the dynamic compressor 100.

[0050] The first supply conduit 565 includes a first valve 570 in fluid connection therewith. The first valve 570 is controlled by the controller 610 and can be selectively positioned to allow refrigerant to flow therethrough. When the first valve 570 is fully closed, all refrigerant in the secondary refrigerant loop 460 will flow through the economizer conduit 465, and the system 900 will operate at the same temperature as the refrigerant in the secondary refrigerant loop 460. Figure 5 The system 800 shown in FIG. 1 operates in substantially the same manner. When the first valve 570 is fully or partially opened, the gaseous refrigerant or two-phase refrigerant leaving the heat exchanger 490 is split into two streams, wherein a portion of the refrigerant flows through the economizer line 465 and the remaining portion of the refrigerant is diverted to flow through the first supply line 565. The first valve 570 may be a solenoid valve (e.g., Figure 6 as shown), an electronic expansion valve, or any type of valve that allows system 900 to function as described herein.

[0051] When the first valve 570 is opened, the first supply conduit 565 provides a first refrigerant flow to facilitate cooling of at least one bearing assembly 200 of the dynamic compressor 100. In the illustrated embodiment, the first supply conduit 565 is split into a first flow 565a, a second flow 565b, and a third flow 565c, which respectively provide the first refrigerant flow to the first radial bearing 200a, the second radial bearing 200b, and the thrust bearing 200c of the dynamic compressor 100. In some embodiments, the first flow 565a, the second flow 565b, and the third flow 565c may each include a valve (not shown) operable to control the flow of refrigerant therethrough.

[0052] The cooling device 560 also includes a return conduit 520 that fluidly connects the first supply conduit 565 to the dynamic compressor 100 to provide a return flow of refrigerant to the dynamic compressor 100. The return conduit 520 collects refrigerant from downstream of the cooled bearings and returns the refrigerant to the inlet 110 of the first compressor stage 124. In the illustrated embodiment, each of the first flow 565a, the second flow 565b, and the third flow 565c of the first supply conduit 565 converges downstream of its respective bearing 200a to 200c to form the return conduit 520. The return flow mixes with the refrigerant flow upstream of the inlet 110, so that the primary refrigerant circuit 410 and the secondary refrigerant circuit 460 converge. The return conduit 520 may include a flowmeter operable to measure the return flow temperature T r The return temperature sensor (not shown) may be a thermocouple, a thermistor, or any suitable temperature sensor.

[0053] Another embodiment of the third example vapor compression system 900 is Figure 7, where the heat exchanger is replaced by a flash tank 590. Downstream of the condenser 320, the refrigerant flow is throttled by the expansion device 480, thereby reducing the pressure of the refrigerant flow until some of the liquid refrigerant in the liquid refrigerant boils, thereby producing a two-phase mixture. The flash tank 590 separates the two-phase refrigerant mixture into a liquid portion and a gaseous portion, which are respectively divided into the primary refrigerant circuit 410 and the secondary refrigerant circuit 460. In some embodiments, a heat exchanger can be used instead of the flash tank 590, or in addition to the flash tank 590. The refrigerant then flows along the primary refrigerant circuit 410 and the secondary refrigerant circuit 460, as described above with respect to Figure 6 as described.

[0054] Figure 8 It can be installed Figure 1 and Figure 2 A schematic diagram of a fourth example vapor compression system 1100 of a dynamic compressor 100 is shown. Figure 6 In addition to the components shown and described in the third example vapor compression system 900, the cooling device 560 of the system 1100 also includes a second supply conduit 665 fluidly connected between the heat exchanger 490 and the motor 108. The secondary refrigerant loop 460 is split into the economizer conduit 465, the first supply conduit 565, and the second supply conduit 665 downstream of the heat exchanger 490. As described above with respect to the third example vapor compression system 900, a portion of the refrigerant flow in the secondary refrigerant loop 460 flows through the economizer conduit 465 and the first supply conduit. The remaining refrigerant flow in the secondary refrigerant loop 460 flows through the second supply conduit 665 to provide the second refrigerant flow to the motor 108.

[0055] The second supply conduit 665 includes a second valve 670 in fluid connection therewith. The second valve 670 is controlled by the controller 610 and can be selectively positioned to allow refrigerant to flow therethrough. When the second valve 670 is fully closed, and when at least one of the economizer valve 470 and the first valve 570 is open, all refrigerant in the secondary refrigerant loop 460 will flow through the economizer conduit 465 and / or the first supply conduit 565, and the system 1100 will flow in a manner similar to that of the first supply conduit 565. Figure 6 The system 900 shown in FIG. 1 operates in substantially the same manner. When the second valve 670 is fully or partially opened, the gaseous refrigerant or two-phase refrigerant leaving the heat exchanger 490 is divided into three streams, wherein a portion of the refrigerant flows through the economizer line 465, another portion of the refrigerant flows through the first supply line 565, and the remaining portion of the refrigerant is diverted to flow through the second supply line 665. The second valve 670 may be a solenoid valve (such as Figure 8as shown), an electronic expansion valve, or any type of valve that allows system 1100 to function as described herein.

[0056] When the second valve 670 is open, the second supply conduit 665 provides a second refrigerant flow to facilitate cooling of the motor 108. The second supply conduit 665 is fluidly connected to the return conduit 520, and the first and second flows combine to form a return flow that mixes with the refrigerant flow upstream of the compressor inlet 110.

[0057] Fig. 9 The diagram shows where you can install Figure 1 and Figure 2 A fifth example vapor compression system 1200 of the dynamic compressor 100 is shown. Figure 8 In addition to all of the components shown and described for the fourth example vapor compression system 1100, the cooling device 560 of the system 1200 further includes a third supply conduit 765 fluidly connected between the heat exchanger 490 and the driver 616. The secondary refrigerant loop 460 is split into an economizer conduit 465, a first supply conduit 565, a second supply conduit 665, and a third supply conduit 765 downstream of the heat exchanger 490. As described above with respect to the fourth example vapor compression system 1100, a portion of the refrigerant flow in the secondary refrigerant loop 460 flows through the economizer conduit 465, the first supply conduit 565, and the second supply conduit 665. The remaining refrigerant flow in the secondary refrigerant loop 460 flows through the third supply conduit 765 to provide the third refrigerant flow to the driver 616.

[0058] The third supply conduit 765 includes a third valve 770 in fluid connection therewith. The third valve 770 is controlled by the controller 610 and can be selectively positioned to allow refrigerant to flow therethrough. When the third valve 770 is fully closed, and when at least one of the economizer valve 470, the first valve 570, and the second valve 670 is open, all refrigerant in the secondary refrigerant loop 460 will flow through the economizer conduit 465, the first supply conduit 565, and / or the second supply conduit 665, and the system 1200 will flow in a manner similar to that of the economizer conduit 465. Figure 8 The system 1100 shown in FIG. 1 operates in substantially the same manner. When the third valve 770 is fully or partially opened, the gaseous refrigerant or two-phase refrigerant leaving the heat exchanger 490 is divided into four streams, wherein a portion of the refrigerant flows through the economizer line 465, another portion of the refrigerant flows through the first supply line 565, another portion of the refrigerant flows through the second supply line 665, and the remaining portion of the refrigerant is diverted through the third supply line 765. The third valve 770 may be a solenoid valve (such as Fig. 9 as shown), an electronic expansion valve, or any type of valve that allows system 1200 to function as shown herein.

[0059] When the third valve 770 is open, the third supply conduit 765 provides a third refrigerant flow to facilitate cooling of the driver 616. The third supply conduit 765 is fluidly connected to the return conduit 520, and the first, second, and third flows are combined to form a return flow that mixes with the refrigerant flow upstream of the compressor inlet 110.

[0060] In another embodiment (not shown), the vapor compression system of the present disclosure may include any combination of the economizer conduit 465, the first supply conduit 565, the second supply conduit 665, the third supply conduit 765, and the return conduit 520 in any suitable configuration.

[0061] The memory 612 stores instructions that program the processor 611 to control the supply of refrigerant to the compressor 100, the motor 108, and the driver 616 based on the operating parameters of each component. Figures 10 to 15 . The processor 611 operates the dynamic compressor 100 to compress the refrigerant, and operates the cooling device 560 to provide a refrigerant flow to one or more bearing assemblies 200 of the dynamic compressor 100 through the first supply conduit 565. When operating the dynamic compressor 100 and the cooling device 560, the processor 611 determines whether a condition is met. If the condition is met, the instructions stored in the memory 612 program the processor 611 to adjust the position of the valve in fluid communication between the dynamic compressor 100 and the cooling device 560.

[0062] In some embodiments, and with reference to Fig.10 , determining whether the condition is satisfied includes determining that the condition is satisfied when the dynamic compressor 100 is no longer operating. In such an embodiment, adjusting the position of the valve includes closing the first valve 570 to suspend the supply of refrigerant to the bearing assembly 200. When it is determined that the dynamic compressor 100 is still operating, it is determined that the condition is not satisfied. When it is determined that the dynamic compressor 100 is still operating, and in an embodiment in which the first valve 570 is a solenoid valve, the instructions stored in the memory 612 program the processor 611 to continue operating the dynamic compressor 100 with the first valve 570 open. In an embodiment in which the first valve 570 is an electronic expansion valve (EXV), the instructions stored in the memory 612 program the processor 611 to continue operating the dynamic compressor 100 with the first valve 570 set to a pressure set point. In some embodiments, the pressure set point P 设定 = equal to the suction pressure P at the inlet 110 of the dynamic compressor 100 吸入 and pressure deviation P 偏差 sum:

[0063] P 设定 =P 吸入 +P偏差

[0064] Pressure deviation P 偏差 This may be 1 psi, 2 psi, or any other suitable pressure deviation that creates a sufficient pressure differential to cause refrigerant to flow through the bearing assembly 200 .

[0065] In an embodiment where the cooling device 560 includes a second supply conduit 665 and a second valve 670 in fluid connection with the second supply conduit 665, instructions stored in the memory 612 program the processor 611 to determine whether the motor 108 is overheated based on the measured return flow or the temperature of the motor 108. For example, and with reference to Fig.11 , determining whether the motor 108 is overheated may include determining the return flow temperature T measured by the return temperature sensor r The temperature of the return temperature is determined by the upper limit threshold T r,up In some embodiments, the return temperature upper limit threshold T r,up It can be, for example but not limited to, 130°F or 140°F. When the temperature of the return flow T r Greater than the return temperature upper limit threshold T r,up In other embodiments, determining whether the motor 108 is overheated may include determining the motor temperature T measured by the motor temperature sensor. m , and determine the upper limit threshold T of the motor temperature m,up In some embodiments, the motor temperature upper limit threshold T m,up It can be, for example but not limited to, 180°F or 200°F. When the motor temperature T m Greater than the upper limit threshold of motor temperature T m,up , the condition is determined to be satisfied.

[0066] When the condition is met in either of these cases, it is determined that the motor 108 is overheated and requires cooling. Therefore, in these embodiments, adjusting the position of the valve includes opening the second valve 670 to provide a second refrigerant flow to the motor 108. When the condition is determined not to be met and the motor 108 is not determined to be overheated, the instructions stored in the memory 612 program the processor 611 to continue operating the dynamic compressor 100 and not adjust the position of the second valve 670.

[0067] In an embodiment where the cooling device 560 includes a third supply conduit 765 and a third valve in fluid connection with the third supply conduit 765, the instructions stored in the memory 612 program the processor 611 to determine whether the driver 616 is overheated based on the temperature of the driver 616 measured by the driver temperature sensor. In such an embodiment, and with reference to Fig.12 , determining that the driver 616 is overheated includes determining the driver temperature T dAnd determine the upper temperature threshold T of the driver d,up In some embodiments, the upper limit threshold of the driving temperature T d,up It can be, for example but not limited to, 160°F or 180°F. When the drive temperature T d Greater than the upper temperature threshold of the driver T d,up , the condition is determined to be satisfied.

[0068] When the condition is met, it is determined that the driver 616 is overheated and requires cooling. Therefore, in such an embodiment, adjusting the position of the valve includes opening the third valve 770 to provide the third refrigerant flow to the driver 616. When the condition is not determined to be met and the driver 616 is not determined to be overheated, the instructions stored in the memory 612 program the processor 611 to continue operating the dynamic compressor 100 and not adjust the position of the third valve 770.

[0069] In some embodiments, the condition is a first condition, and the instructions stored in the memory 612 further program the processor 611 to determine whether a second condition is met and adjust the position of the valve when the second condition is met. For example, the instructions stored in the memory 612 program the processor 611 to determine whether the motor 108 and the driver 616 have sufficiently cooled after the second valve 670 or the third valve 770 is opened.

[0070] For example, refer to Fig.13 , determining whether the motor 108 is undercooled may include determining the temperature T of the return flow r And determine the return temperature lower limit threshold T r,low In some embodiments, the return temperature lower limit threshold T r,low Returns the upper temperature threshold T r,up And the return temperature dead zone value T r、db The difference between:

[0071] T r，low =T r，up -T r，db

[0072] Determining whether the motor 108 is too cold may also include determining the motor temperature T m And determine the motor temperature lower limit threshold T m,low In some embodiments, the motor temperature lower limit threshold T m,low is the upper limit threshold of motor temperature T m,up and motor temperature dead zone value T m、db The difference between:

[0073] T n，low =T m，up -T m，db

[0074] The motor temperature deadband may be, for example but not limited to, 10 degrees Fahrenheit or 15 degrees Fahrenheit. r Lower than the return temperature lower limit threshold T r,low and / or motor temperature T m Lower than the motor temperature lower limit threshold T m,low , it is determined that the second condition is satisfied.

[0075] When the second condition is met in either of these cases, it is determined that the motor 108 is sufficiently cooled and no longer requires cooling. Therefore, in such an embodiment, the position of the regulating valve includes closing the second valve 670 to terminate the second refrigerant flow to the motor 108. When the second condition is not determined to be met and the motor 108 is not determined to be undercooled, the instructions stored in the memory 612 program the processor 611 to continue operating the dynamic compressor 100 with the second valve 670 open.

[0076] Similarly, refer to Fig.14 , determining whether the driver 616 is too cold may include determining the measured driver temperature T d And determine the lower limit threshold of the driver temperature T d,low In some embodiments, the driver temperature lower limit threshold T d,low is the upper temperature threshold of the driver T d,up and the driver temperature dead zone value T d、db The difference between:

[0077] T d，low =T d，up -T d，db

[0078] When the measured driver temperature T d Less than the driver temperature lower limit threshold T d,low , it is determined that the second condition is satisfied.

[0079] In such embodiments, when the second condition is met, it is determined that the driver 616 is sufficiently cooled and no longer requires cooling. Therefore, in these embodiments, the position of the regulating valve includes closing the third valve 770 to terminate the third refrigerant flow to the driver 616. When the second condition is not determined to be met and the driver 616 is not determined to be undercooled, the instructions stored in the memory 612 program the processor 611 to continue operating the dynamic compressor 100 with the third valve 770 open.

[0080] Fig.15 yes Figures 11 to 14 Flow chart of an example control algorithm for controlling the operation of the cooling device 560 when the motor 108 or the drive 616 is overheated or undercooled. rand / or motor temperature T m has exceeded its respective upper threshold T r,up 、T m,up , the second valve 670 is set to open. r and motor temperature T m Both fall below their respective lower thresholds T r,low 、T m,low When the driver temperature T d Exceeds its upper threshold T d,up , the third valve 770 is set to open. d falls below its lower threshold T d,low , the third valve 770 is reset to closed.

[0081] Technical advantages of the method and system include: the vapor compression system can use existing steam paths from the energy saving system to provide steam injection cooling to the bearings, motors and drives of the dynamic compressor. In addition, the bearings, motors and drives of the dynamic compressor can be cooled using steam injection without the risk of flooding the bearings or compressor flow paths with liquid. Steam injection is also more suitable for the small amount of cooling required for the bearings.

[0082] As used herein, the terms "about," "substantially," and "approximately" when used in conjunction with ranges of size, concentration, temperature, or other physical or chemical properties or characteristics are meant to encompass variations that may exist in the upper and / or lower limits of the range of the property or characteristic, including variations caused, for example, by rounding, measurement method, or other statistical variations.

[0083] When introducing elements of the present disclosure or embodiments of the present disclosure, the expressions "a," "an," "the," and "said" are intended to indicate that there are one or more elements. The terms "comprising," "including," "containing," and "having" are intended to be inclusive and mean that additional elements may be present in addition to the listed elements. The use of terms indicating a particular orientation (e.g., "top," "bottom," "side," etc.) is for convenience of description and does not require any particular orientation of the described items.

[0084] As various changes could be made in the above constructions and methods without departing from the scope of the present disclosure, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Claims

1. A steam compression system comprising: A primary circuit, the primary circuit comprising: A dynamic compressor operable to compress a refrigerant, the dynamic compressor comprising: case; a shaft supported in the housing by bearings; and an impeller connected to the shaft; a motor operably connected to the shaft to drive the shaft to rotate; and a driver operable to control the motor; a condenser fluidly connected to the dynamic compressor; a first expansion device fluidly connected to the condenser; and an evaporator fluidly connected to the first expansion device and the dynamic compressor; and A secondary loop, the secondary loop comprising: a second expansion device fluidly connected to the condenser; a heat exchanger fluidly connected to the second expansion device, the condenser, and the dynamic compressor; and A supply conduit is fluidly connected between the heat exchanger and the dynamic compressor to provide a refrigerant flow to the bearing.

2. The vapor compression system according to claim 1, wherein: The supply conduit includes a valve operable to control the flow of the refrigerant therethrough.

3. The vapor compression system of claim 1, wherein: The heat exchanger is a flash tank.

4. The vapor compression system of claim 1, wherein: The secondary circuit further comprises a return conduit for fluidly connecting the supply conduit to the dynamic compressor to provide a return flow of refrigerant to the dynamic compressor.

5. The vapor compression system of claim 1, wherein: The supply conduit is a first supply conduit and the refrigerant flow is a first refrigerant flow, wherein the secondary circuit further comprises a second supply conduit for fluidly connecting the heat exchanger to the motor to provide a second refrigerant flow to the motor.

6. The vapor compression system of claim 5, wherein: The secondary circuit further comprises a third supply conduit for fluidly connecting the heat exchanger to the driver to provide a third refrigerant flow to the driver.

7. The vapor compression system of claim 6, wherein: The secondary loop further includes a return conduit for fluidly connecting the first supply conduit, the second supply conduit, and the third supply conduit to the dynamic compressor to provide a return flow of refrigerant to the dynamic compressor.

8. The vapor compression system of claim 1, wherein: The secondary loop further includes an economizer conduit for fluidly connecting the heat exchanger to the dynamic compressor to provide an economizer flow of refrigerant to the dynamic compressor between the first stage and the second stage of the dynamic compressor.

9. A controller for a compressor system, the compressor system comprising a dynamic compressor and a cooling device, the cooling device comprising a heat exchanger and a supply conduit fluidly connected between the heat exchanger and the dynamic compressor, the controller comprising: processor; as well as a memory storing instructions for programming the processor to: operating the dynamic compressor to compress refrigerant; operating the cooling device to provide a flow of refrigerant through the supply conduit to a bearing of the dynamic compressor; Determine whether the conditions are met; as well as When the condition is met, a position of a valve in fluid communication between the dynamic compressor and the cooling device is adjusted.

10. The controller according to claim 9, wherein: The valve is a first valve fluidly connected to the supply conduit between the heat exchanger and the at least one bearing, wherein determining whether the condition is met includes determining that the condition is met when the dynamic compressor is no longer operating, and wherein adjusting the position of the valve includes closing the first valve.

11. The controller according to claim 9, wherein: The supply conduit is a first supply conduit and the refrigerant flow is a first refrigerant flow, wherein the cooling device also includes a second supply conduit, the second supply conduit being used to connect the heat exchanger fluid to a motor operatively connected to the dynamic compressor, and wherein the second supply conduit provides a second refrigerant flow to the motor.

12. The controller according to claim 11, wherein: The cooling device also includes: a second valve, which is fluidly connected to the second supply pipe between the heat exchanger and the motor; a return pipe, which is used to fluidly connect the first supply pipe and the second supply pipe to the dynamic compressor to provide a return flow of refrigerant to the dynamic compressor; and a return temperature sensor, which is operable to measure the temperature of the return flow, wherein determining whether the condition is met includes determining that the condition is met when the temperature of the return flow is greater than a return temperature upper limit threshold, and wherein the position of the regulating valve includes opening the second valve.

13. The controller according to claim 11, wherein: The motor includes a motor temperature sensor operable to measure a temperature of the motor, wherein determining whether a condition is satisfied includes determining that the condition is satisfied when the temperature of the motor is greater than an upper motor temperature threshold, and wherein the position of the regulating valve includes opening a second valve connected to the second supply conduit fluid between the heat exchanger and the motor.

14. The controller according to claim 11, wherein: The cooling device further comprises a third supply conduit for fluidly connecting the heat exchanger to a drive operable to control the motor, and wherein the third supply conduit provides a third refrigerant flow to the drive.

15. The controller according to claim 14, wherein: The driver includes a driver temperature sensor operable to measure a temperature of the driver, wherein determining whether a condition is satisfied includes determining that the condition is satisfied when the temperature of the driver is greater than an upper driver temperature threshold, and wherein the position of the regulating valve includes opening a third valve fluidly connected to the third supply conduit between the heat exchanger and the driver.

16. The controller according to claim 9, wherein: The condition is a first condition, and the memory further stores instructions programming the processor to: determining whether a second condition is satisfied; and When the second condition is met, the position of the valve is adjusted.

17. The controller according to claim 16, wherein: The supply conduit is a first supply conduit, and the refrigerant flow is a first refrigerant flow, and wherein the cooling device further comprises: a second supply conduit for supplying a second refrigerant flow from the heat exchanger to a motor operatively connected to the dynamic compressor; a second valve fluidly connected to the second supply conduit; a return conduit for supplying a return flow of refrigerant from the first supply conduit and the second supply conduit to the dynamic compressor; and a return temperature sensor operable to measure a temperature of the return flow, wherein determining whether the second condition is satisfied comprises determining that the second condition is satisfied when the temperature of the return flow is less than a return temperature lower limit threshold, and Wherein, adjusting the position of the valve includes closing the second valve.

18. The controller according to claim 16, wherein: The supply conduit is a first supply conduit, and the refrigerant flow is a first refrigerant flow, and wherein the cooling device further comprises: a second supply conduit for supplying a second refrigerant flow from the heat exchanger to a motor operatively connected to the dynamic compressor; a second valve fluidly connected to the second supply conduit; a return conduit for supplying a return flow of refrigerant from the first supply conduit and the second supply conduit to the dynamic compressor; and a motor temperature sensor operable to measure a temperature of the motor, wherein determining whether the second condition is satisfied comprises determining that the second condition is satisfied when the temperature of the motor is less than a motor temperature lower limit threshold, and Wherein, adjusting the position of the valve includes closing the second valve.

19. The controller according to claim 16, wherein: The supply conduit is a first supply conduit, and the refrigerant flow is a first refrigerant flow, and wherein the cooling device further comprises: a third supply conduit for supplying a third refrigerant flow from the heat exchanger to a driver operable to control a motor operatively connected to the dynamic compressor; a third valve fluidly connected to the third supply conduit; and a driver temperature sensor operable to measure a temperature of the driver, wherein determining whether the second condition is satisfied comprises determining that the second condition is satisfied when the temperature of the driver is less than a driver temperature lower limit threshold, and Wherein, adjusting the position of the valve includes closing the third valve.

20. A compressor system, comprising: A dynamic compressor operable to compress a refrigerant, the dynamic compressor comprising: case; a shaft supported in the housing by bearings; and an impeller connected to the shaft; and A cooling device, the cooling device comprising: a heat exchanger fluidly connected to the dynamic compressor; a supply conduit fluidly connected between the heat exchanger and the dynamic compressor to provide a refrigerant flow to the bearing; a valve fluidly connected to the supply conduit and selectively positionable to allow refrigerant to flow through the valve; and A controller is operable to control the valve.

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