Anti-surge vent system

Abstract

A HVAC&R system, includes a refrigeration circuit configured to circulate refrigerant. Further, the system includes a compressor (100) disposed between a condenser (206) and an evaporator (204) along the refrigeration circuit, wherein the compressor (100) is configured to receive and compress the refrigerant from the evaporator (204) and direct the refrigerant from the compressor (100) to the condenser (206). A housing of the compressor (100) includes a suction chamber (104) configured to supply the refrigerant to an impeller (106) of the compressor (100) and a discharge chamber (110) configured to receive the refrigerant from a diffuser (108) of the compressor (100). A vent system (112) integrated with the housing of the compressor (100) is configured to bypass the impeller (106) to route the refrigerant from the diffuser (108) to the suction chamber (104) during surge conditions or impeding surge conditions.

Description

ANTI-SURGE VENT SYSTEMCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from and the benefit of U.S. Provisional Patent Application No. 63 / 651,302. entitled “ANTI-SURGE VENT SYSTEM,” filed May 23, 2024, which is hereby incorporated by reference in its entirety for all purposes.BACKGROUND

[0002] This application relates generally to vapor compression systems such as chillers, and more specifically to a compressor of a chiller.

[0003] This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present techniques, which are described and / or claimed 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 admission of prior art.

[0004] Vapor compression systems (e.g., chillers) utilize a working fluid, typically referred to as a refrigerant, which changes phase between vapor, liquid, and combinations thereof in response to being subjected to different temperatures and pressures associated with operation of the vapor compression system. For example, a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system may include a chiller, which is a type of vapor compression system that cycles a refrigerant to remove heat from, or cool, a flow of water traversing tubes that extend through a chiller evaporator. The chilled water flow may be directed to nearby structures to absorb heat, or provide cooling, before being cycled back to the chiller evaporator to be cooled once again.

[0005] HVAC&R systems, such as chiller systems, utilize compressors, such as centrifugal compressors, to compress the refrigerant as part of a refrigeration cycle, and to motivate the refrigerant through the HVAC&R system. In certain phases of operation, it is now recognized that these compressors can experience surge, which is detrimental to overall operations.SUMMARY

[0006] Certain embodiments commensurate in scope with the originally claimed subject matter are summarized below. These embodiments are not intended to limit the scope of the claimed subject matter, but rather these embodiments are intended only to provide a brief summary of possible forms of the subject matter. Indeed, the subject matter may encompass a variety of forms that may be similar to or different from the embodiments set forth below.

[0007] In accordance with an embodiment of the present disclosure, a HVAC&R system, includes a refrigeration circuit configured to circulate refrigerant. Further, the system includes a compressor disposed between a condenser and an evaporator along the refrigeration circuit, wherein the compressor is configured to receive and compress the refrigerant from the evaporator and direct the refrigerant from the compressor to the condenser. A housing of the compressor includes a suction chamber configured to supply the refrigerant to an impeller of the compressor and a discharge chamber configured to receive the refrigerant from a diffuser of the compressor. A vent system integrated with the housing of the compressor is configured to bypass the impeller to route the refrigerant from the diffuser to the suction chamber during surge conditions or impeding surge conditions.

[0008] In accordance with another embodiment of the present disclosure, a HVAC&R system, includes a refrigeration circuit configured to circulate refrigerant. A compressor is disposed between a condenser and an evaporator along the refrigeration circuit, wherein the compressor is configured to receive and compress the refrigerant from the evaporator and direct the refrigerant from the compressor to the condenser. A housing of the compressor includes a suction chamber configured to supply the refrigerant to an impeller of the compressor and a discharge chamber configured to receive the refrigerant from the impeller. A vent system integrated with the housing of the compressor is configured to bypass the impeller to route the refrigerant from a diffuser to the suction chamber upon detection of conditions predictive of surge conditions.

[0009] In accordance with a further embodiment of the present disclosure, a compressor system for a HVAC&R system includes a compressor housing, an impeller and a diffuser configured to compress refrigerant to provide compressed refrigerant, a suction chamber of the compressor housing configured to supply the refrigerant to the impeller, a discharge chamber of the housing configured to receive the compressed refrigerant from the diffuser; and a ventsystem integrated with the housing and configured to bypass the impeller to route the compressed refrigerant from the diffuser to the suction chamber during surge conditions or impeding surge conditions.

[0010] It is appreciated that implementations in accordance with the present disclosure can include any combination of the aspects and features described herein. That is, implementations in accordance with the present disclosure are not limited to the combinations of aspects and features specifically described herein, but also include any other appropriate combinations of the aspects and features provided.BREIF DESCRIPTION OF THE DRAWINGS

[0011] These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

[0012] FIG. 1 is a block diagram of an embodiment of a compressor, in accordance with an embodiment of the present disclosure;

[0013] FIG. 2 is a schematic diagram of an embodiment of the compressor of FIG. 1, in accordance w ith an embodiment of the present disclosure;

[0014] FIG. 3 is a process flow diagram illustrating a method for controlling a vent system included in the compressor in FIG. 1, in accordance with an aspect of the present disclosure; and

[0015] FIG. 4 is a block diagram of an example control system controlling a vent system, in accordance with an embodiment of the present disclosure.DETAILED DESCRIPTION

[0016] 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 implementationspecific decisions must be made to achieve the developers’ specific goals, such as compliancewith 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.

[0017] 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.

[0018] In a HVAC&R system, a compressor may include a suction chamber that receives refrigerant from an evaporator, an impeller and a diffuser that collaborate to compress the refrigerant, and a discharge chamber that directs the refrigerant to a condenser. It is presently recognized that the compressor may encounter instabilities such as surge during operation. Surge may be broadly described as a backflow of refrigerant through the compressor. More specifically, surge may be defined as a transient phenomenon having oscillations in pressures and flow that can result in complete flow reversal through the compressor. Surge, if uncontrolled, can cause excessive vibrations in both the rotating and stationary7components of the compressor, and may result in permanent compressor damage. Additionally, the reversed flow during a surge event may overload certain components of the compressor. For example, the reverse flow may apply a force against bearings of a compressor. Often, the operation of the HVAC&R system must be halted to avoid any damage to the system upon detection of an impending surge event, causing a reduction of overall efficiency of the system. Accordingly, it is presently recognized that it would be desirable to reduce the effects of surge on the compressor.

[0019] The present disclosure is directed to a HVAC&R system including a vent system integrate within the compressor. The vent system may include a vent path extending from the diffuser to the suction chamber, external to the impeller. During surge conditions, the vent system may route a reversed refrigerant flow through the vent path, bypassing the impeller. As such, the effect of the reversed refrigerant flow on the impeller may be mitigated. In someembodiments, the vent system may include a control valve that opens access to the vent path during the surge conditions and blocks access to the vent path outside of the surge conditions.

[0020] Turning now to drawings, FIG. 1 illustrates an embodiment of a centrifugal compressor 100, which is included in a HVAC&R system. The compressor 100 may be disposed between an evaporator and a condenser, such that refrigerant 102 from the evaporator may have an increase in pressure before it enters the condenser. The compressor 100 may include a suction chamber 104, an impeller 106, a diffuser 108, a discharge chamber 110, and a vent system 112 (also referred to as an anti-surge vent system 112). It should be noted that the vent system 112 is internal to the compressor 100 (e.g., disposed within a housing of the compressor) and external to the impeller 106. The vent system 112 is configured to route a reversed refrigerant flow from the diffuser 108 to the suction chamber 104 without passing through the impeller 106 during surge conditions. As such, the impeller 106 may be protected from the full effect of the reversed refrigerant flow during a surge.

[0021] In some embodiments, the refrigerant 102 may be a synthetic refrigerant (e.g., chlorofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC), hydrofluorocarbon (HFC), hydrofluoroolefin (HFO)), a natural refrigerant (e.g., water, ammonia, carbon dioxide, hydrocarbon (HC; such as propane, butane, and ethane)), a refrigerant blend (e.g., R-407c), or another suitable refrigerant that may be compressed into a liquid and expanded into a vapor in the HVAC&R system. In some embodiments, the refrigerant 102 enters the compressor 100 from the evaporator upstream of the compressor 100 in the HVAC&R system in a lower- pressure, low-temperature vapor form and exits the compressor 100 to the condenser downstream in a high-pressure, high-temperature vapor form.

[0022] The refrigerant 102 exiting the evaporator may be sucked into the suction chamber 104 of the compressor 100 via an inlet path. In some embodiments, the suction chamber 104 is configured to introduce the refrigerant 102 from the inlet path evenly into the impeller 106. In some embodiment, the suction chamber 104 includes a scroll cavity. Then, the refrigerant 102 is pressurized in the impeller 106. In some embodiments, the impeller may include multiple impeller vanes disposed on an impeller plate, extending outwards from an impeller shaft to the edge of the impeller plate at a certain angle. During operation, the refrigerant 102 may flow radially outwards along the multiple impeller vanes. In some embodiments, the multiple impeller vanes may be configured to increase operating efficiency of the impeller. For example, the multiple impeller vanes may be configured to provide an initial swirl to therefrigerant 102 entering the impeller to reduce fluid head loss. In some embodiments, the impeller 106 is configured to increase a velocity of the refrigerant 102 by rotating the impeller plate via the impeller shaft at a certain angular velocity. As such, the pressure of the refrigerant 102 increases as the velocity increases.

[0023] The compressor 100 may also include a motor to drive the rotation of the impeller shaft. The motor may be powered by a variable speed drive (VSD). The VSD receives alternating current (AC) power having a particular fixed line voltage and fixed line frequency from an AC power source, and provides power having a variable voltage and frequency to the motor. In other embodiments, the motor may be powered directly from an AC or direct current (DC) power source. The motor may include any type of electric 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.

[0024] The compressor 100 may also include a bearing to support the impeller shaft. In some embodiments, the bearing may include a thrust bearing and a plurality of journal bearings. The bearing may employ oil as a lubricant to reduce friction. In other embodiments, the bearing may be a magnetic bearing to increase efficiency and reduce maintenance needs. The magnetic bearing may include a rotor (or a rotating part) and a stator (or a stationary part). In some embodiments, the rotor may include at least one magnet, and the stator may include at least one electromagnet to generate a magnetic field. As such, a magnetic force may be applied to the rotor to achieve a desired position.

[0025] The refrigerant 102 from impeller 106 is then passed to the diffuser 108 in a high velocity. The increased velocity7(or kinetic energy ) the refrigerant 102 obtained in the impeller 106 is converted to an additional increase in pressure (or internal energy) in the diffuser 108. Specifically, the velocity of the refrigerant 102 is reduced by expanding a cross-sectional area of the refrigerant 102 to recover the static pressure in the diffuser 108. In some embodiments, the diffuser may be configured to have a gradually increasing cross-sectional area. For example, the diffuser 108 may be a radial annular passage with a gradually expanding circulation cross-section around an outer edge of the impeller 106. In some embodiments, the diffuser 108 may be a vaneless diffuser. In other embodiments, the diffuser 108 may be a vaned diffuser and have multiple diffuser vanes to increase efficiency of the pressure recovery. In some embodiments, the diffuser 108 may be a variable geometry diffuser (VGD) to helpstabilize the refrigerant 102 during extreme conditions. For example, the VGD may be configured to include a diffuser ring movable within a diffuser gap at the impeller exit to restrict the refrigerant 102 through the diffuser gap during stall conditions, which are indicative of a reduction of refrigerant in the diffuser 108.

[0026] The refrigerant 102 from diffuser 108 may be collected in a discharge chamber 110 (i.e., collector) and directed to exit the compressor 100 through a discharge passage. The discharge chamber 110 may be a plenum collector, a volute collector, or another discharge chamber of a suitable shape or form. In some embodiment, the refrigerant 102 may pass through the volute collector to an additional stage of compression.

[0027] During normal operating conditions, the refrigerant 102 is sucked into the suction chamber 104, pressurized in the impeller 106 and the diffuser 108, collected in the discharged chamber 110, and directed to exit the compressor 100, as described above. However, surge conditions may begin developing in the compressor 100 as a result of a pressure imbalance between the compressor 100 and a downstream component (e g., condenser), among other reasons. The surge conditions may lead to formation of a reversed refrigerant flow in the compressor 100, which may cause permanent damage to the impeller 106 and overload a bearing system of the compressor 100.

[0028] To mitigate the potential consequences of surge conditions, in the illustrated embodiment, the compressor 100 further includes the vent system 112, which is integrated with and internal to the compressor 100 (e.g., inside a housing of the compressor 100) to divert the reversed refrigerant flow away from the impeller 106 during surge conditions. The vent system 1 12 may include a vent path extending from the diffuser 108 to the suction chamber 104, external to the impeller 106. The vent system 112 may further include an access control configured to be actuated by a controller to open or block access to the vent path of the vent system 112.

[0029] In order to help illustrate the vent system 112 and the associated mechanism to divert a reversed flow during surge conditions, an embodiment of the compressor 100 of FIG. 1, illustrated as compressor 200, is shown in FIG. 2.

[0030] In the illustrated embodiment, the compressor 200 may be integrated within a HVAC&R system to receive refrigerant flow 202 from an evaporator via a compressor inlet path 204, compress the refrigerant flow 202, and direct the refrigerant flow 202 via acompressor outlet path 206 to a condenser. The compressor 200 includes a suction chamber 208, an impeller 210, a diffuser 212. a discharge chamber 214, and a vent system 216.

[0031] The vent system 216 may be configured to effectively divert a reversed refrigerant flow 203 from the diffuser 212 to the suction chamber 208 without passing through the impeller 210 during surge conditions. In the illustrated embodiment, the vent system 216 includes a vent path 218 extending from the diffuser 212 to the suction chamber 208, external to the impeller 210, to route a portion of the reversed refrigerant flow 203 away from the impeller 210. In some embodiments, the vent path 218 is configured to extend from a diffuser nozzle base plate. In certain embodiments, the vent path 218 may include a fan or a booster (e.g., a pump) to facilitate drawing the portion of the reversed refrigerant flow 202 into the vent path 218.

[0032] Since surge conditions are present only a very' small percentage of the time that the compressor 200 operates, the operation of the vent system 216 similarly has been limited. As such, the vent system 216 may be configured to block access to the vent path 218 during normal operating conditions. Accordingly, in some embodiments, the vent system 216 may include an access control 220, which may include portals into and / or out of the vent path 218 that are sized and / or positioned to minimize flow through the vent path during normal operating conditions. While access control 220 is depicted with a traditional valve symbol, it will be understood to represent any of various types of access control features. For example, in addition to calibrated openings, it may also represent one or more valves, flaps, ports, seals, and so forth.

[0033] As described herein, in some embodiments, the vent system 216 may be configured to only allow access to the vent path 218 as needed. Hence, a barrier that can be actuated may be incorporated into the vent system 216. For example, in the illustrated embodiment, the access control 220 may be a barrier, such as a valve (e.g., gate valve, glove valve, ball valve, butterfly valve) configured to allow the reversed refrigerant flow 202 in the diffuser 212 to pass through the vent path 218 during surge conditions and block the refrigerant flow 202 from entering the vent path 218 during normal operating conditions. Alternatively, the access control 220 may be barrier such as a flap gate configured to permit flow in normal direction of the refrigerant flow 202 while preventing and sealing against the flow in the opposite direction. In some embodiments, the access control 220 may include a biased valve or a biased flap thatis calibrated to open upon exposure to pressure levels associated with the surge conditions without using a controller.

[0034] In some embodiments, the vent system 216 operates in conjunction with an actuator 222 and a controller 224. As such, the controller 224 may open or close the access control 220 via the actuator 222 to effectively control the access to the vent path 218 upon detection of surge conditions or impending surge conditions. One or more sensors 226 may be used for detecting surge conditions or impending surge conditions in the compressor 200. For example, the one or more sensors 226 may be configured to capture flow characteristics, such as flow rate and pressure, and / or acoustic characteristics to monitor the flow in the compressor 200 and / or detect surge conditions or impending surge conditions. The sensor readings may be compared to a surge map of the compressor 200 to determine whether the current operating conditions are indicative of a surge or an impeding surge, wherein the surge map includes a surge line indicative of operating boundaries of the compressor 200. As another example, the one or more sensors 226 may be configured to measure a resultant force on a bearing system of the compressor 200. In some embodiments, a direction of the resultant force may be utilized to determine whether a reverse flow indicative of a surge is present in the compressor 200. In some embodiments, changes of the measured resultant force (e.g., magnitude and / or direction) on a bearing system may be utilized to detect a surge or an impeding surge.

[0035] Then, the controller 224 of the compressor 200 may be provided to process the sensor data and instruct control signals accordingly to control the vent system 216. In some embodiments, the controller 224 may include a processor 228, a memory 230, communication circuitry 232, and / or an interface 234 collaborated together to monitor, detect, and mitigate surge conditions.

[0036] Thus, the controller 224 may operate to provide control signals to the actuator 222, to receive and process the sensor data, and so forth. The memory 230 may include volatile memory, such as random-access memory (RAM), and / or non-volatile memory, such as readonly memory (ROM), optical drives, hard disc drives, solid-state drives, or any other non- transitory computer-readable medium that includes instructions to actuate the barrier. The processor 228 may be configured to execute such instructions. For example, the processor 228 may include one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs), one or more general-purpose processors, or any combination thereof. The memoi ' 230 may include one or more memories, and / or theprocessor 228 may include one or more processors. Accordingly, the controller 224 may refer to any configuration of one or more memories and / or one or more processors that operate together to carry out techniques disclosed herein. For example, the controller 224 may include processing circuitry with one processor to perform certain operations, another processor to perform other operations, and so forth. In some embodiments, the controller 224 may communicate (e.g., via wired or wireless protocols) with other components of the compressor 200 using the communication circuitry 232 to enable automatic actuation of the barrier upon detection of a surge or an impending surge. For example, the controller 224 may be provided with communication circuitry 232 such that the controller 224 may electronically communicate with the sensors 226 and the actuator 222 to receive the sensor data and output control instructions in real time (e.g., substantially real time, such as within milliseconds).

[0037] Additionally, the controller 224 may include an interface 234 (e.g., input / output board), which may be configured to provide manual instructions to components of the compressor 200. The interface 234 may include one or more input devices such as a keyboard, a mouse, or other devices. In certain embodiments, the interface 234 may also include one or more output devices such as a display, LED(s), an audio output device (e.g., a speaker), and so forth. The interface 234 may be physically incorporated in one or more computing devices of the compressor 200 or may be external on one or more computing devices of the compressor 200.

[0038] In accordance with various embodiments described above, the compressor 200 may include the controller 224 to automate the diversion of a reversed flow upon detection of surge conditions or impending surge conditions, thereby decreasing the risks of permanent damage and increasing the overall efficiency of the compressor 200. FIG. 3 illustrates a flow diagram of a method 300 by which a controller of a compressor (e.g., the compressor 200 described above) may control a vent system (e.g., the vent system 216) including the access control 220, such as a barrier (e.g., one or more valves) to divert a reversed flow during surge conditions in accordance with such embodiments.

[0039] The method 300 includes detecting (block 302) a surge event based on sensor readings, as described above with reference to FIG. 2. For example, the one or more sensors 226 may be configured to capture flow characteristics, such as a flow rate and a pressure, which may be sent to be processed at the controller 224 to determine whether the flow characteristics are indicative of a surge event or an impending surge event. A surge map including a surgeline indicative of operating boundaries of the compressor 200 may be used. In some embodiments, a surge event is detected when the captured flow characteristics are beyond the surge line on the surge map. In some embodiments, the surge event may be deemed active by an operator in charge of operations of the compressor 200. The operator may determine certain sensor readings as indicative of a surge event or an impending surge event, which may not be characterized the same way by the controller 224. In some embodiments, historical sensor readings of the compressor 200 and / or similar compressors may be studied to identify a relationship between the sensor readings and flow conditions (e.g., normal operating conditions vs. surge conditions) in the compressor 200. In some embodiments, a machine learning model may be used to identify the relationship between the sensor readings and flow conditions. As used herein, machine learning models refers to algorithms and statistical models that may be used to perform a specific task without using explicit instructions, relying instead on patterns and inference. In particular, a machine learning model generates a mathematical model based on data (e.g., sample or training data) in order to make predictions or decisions without being explicitly programmed to perform the task. For example, as historical sensor readings of the compressor 200 and / or similar compressors may be trained by a machine learning model, patterns may be identified via the machine learning model to determine whether a particular set of sensor readings may be indicative of normal flow conditions and / or surge conditions. The identified relationship may be utilized to detect any surge event or any impending surge event in lieu of or in addition to the surge map. The one or more sensors 226 may continuously monitor the flow characteristics in the diffuser 212 in real time (e.g., substantially real time, such as within milliseconds), such that the controller 224 may output the control instructions to the actuator 222 in a timely manner.

[0040] The method 300 also includes adjusting (block 304) an anti-surge valve (e.g., the access control 220) to divert surge flow to a suction chamber (e.g., the suction chamber 208). After the controller 224 detects an active surge event or an impending surge event based on the sensor readings indicative of surge conditions, the controller 224 may output the control instructions to the actuator 222 to actuate the access control 220 such that the access to the vent system 216 is open. In response to the control instructions, the actuator 222 may actuate the access control 220 to an open position and a reversed flow resulting from the surge event may be routed through the vent path 218. In some embodiments, the operator in charge of the operations of the compressor 200 may determine current sensor readings are indicative of a surge event and proceed to manually send instructions to the actuator 222 to open the accesscontrol 220 via the I / O device 234. The vent path 218 may be configured such that the portals into and / or the vent path 218 are sized and / or positioned to minimize flow through the vent path during normal operating conditions and maximize the flow through the vent path during surge conditions.

[0041] The method 300 also includes determining (block 306) whether the detected surge event remains active. In some embodiments, the controller 224 may determine whether the detected surge event remains active based on additional sensor readings received after the control instructions to open the access control 220 are outputted to the actuator 222. The controller 224 may compare the additional sensor readings to the operating boundaries indicated by the surge line on the surge map. The controller 224 may determine that the detected surge event remains active if the additional sensor readings are beyond the operating boundaries and determine that the detected surge event is no longer active if the additional sensor readings are within the operating boundaries. Alternatively, or additionally, the relationship between the sensor readings and flow conditions identified using historical sensor readings may be utilized to make the determination. In some embodiments, the operator in charge of the operations of the compressor 200 may determine whether the surge event is still active by comparing the additional sensor readings to additional operating boundaries more or less conservative than the operating boundaries indicated by the surge line on the surge map and overrides the determination made by the controller 224.

[0042] If the surge event is deemed to remain active, the controller 224 may proceed to output control instructions to the actuator 222 such that the access control 220 remains open. In some embodiments, the method 300 continuously loops back to blocks 304 and 306 until the surge event is deemed inactive at block 306. For example, the controller 224 may continuously evaluate the sensor readings in real time (e.g., substantially real time, such as within milliseconds) and instruct the actuator to hold until the sensor readings are no longer indicating an active surge event. In some embodiments, the controller 224 may determine to halt the operation of the compressor 200 upon receiving sensor readings indicative of an extreme surge event and thereby interrupt the loop to blocks 304 and 306. The extreme surge event may be a surge event that cannot be effectively mitigated within a certain period of time and / or a surge event that may cause continuation of the operation deemed inappropriate. For example, the controller 224 may send instructions to halt the operation of the compressor 200 upon receiving sensor readings indicative of a prolonged active surge event that lasts longerthan a threshold period of time. As another example, the controller 224 may send instructions to halt the operation of the compressor 200 upon receiving sensor readings indicative of a resultant force on a bearing system exceeding a capacity limit of the bearing system.

[0043] In contrast, if the surge event is deemed to be no longer active, the controller 224 may proceed to output control instructions to the actuator 222 such that the access control 220 (e.g., valve) closes (block 308). The access to the vent path 218 which routes the flow from the diffuser 212 to the suction chamber 208 is thereby closed. In some embodiments, the controller 224 may continue to monitor the sensor readings after the access to the vent path 218 is closed. In some embodiments, the controller 224 may be programmed such that it may process the sensor readings continuously in real time (e.g., substantially real time, such as within milliseconds) such that the compressor 200 may mitigate any surge events or impending surge events following steps described in the method 300.

[0044] In some embodiments, the barrier in the vent system 216 may be actuated to either an open position or a closed position. In contrast, in some embodiments, the barrier in the vent system 216 may be adjusted to a certain position between a substantially open position, wherein the refrigerant flow 202 is essentially unimpeded, and a completely closed position, wherein the refrigerant flow 202 is blocked. In some embodiments, the position of the barrier may be calibrated to correlate to the amount of refrigerant flow 202 diverted from the diffuser 212.

[0045] Hence, the amount of refrigerant flow 202 diverted from the diffuser may be controlled by instructing the actuator 222 to actuate the barrier to a certain position. For example, the controller 224 may instruct the actuator 222 to adjust a degree of opening of the access control 220 to increase or decrease the amount of refrigerant flow 202 through the vent path 218. In some embodiments, the controller 224 may receive sensor readings including a flow rate and a pressure indicative of surge conditions in the diffuser 212 and adjust the access control 220 to a certain degree of opening determined by at least the flow rate and the pressure, such that an optimal amount of flow may pass through the vent path 218 to effectively mitigate the surge conditions. In some embodiments, the controller 224 may receive sensor readings including a resultant force on the bearing system and adjust the access control 220 to a certain degree of opening such that the resultant force does not exceed a capacity limit of the bearing system.

[0046] FIG. 4 is a block diagram of an example control system 400 controlling a vent system 216, in accordance with an embodiment of the present disclosure. As described herein, in response to detecting a surge event or an impending surge event based on sensor readings beyond operating boundaries of the compressor 200, the controller 224 may provide a notification to the control system 400 of the vent system 216. The control system 400 may in turn take certain actions to adjust the degree of opening of the access control 220 and thereby adjust the amount of reversed refrigerant flow through the vent path 218 to mitigate the surge conditions.

[0047] For example, the control system 400 may adjust a flow of the reversed refrigerant flow into the vent system 216 by electronically communicating with sensors (e.g., one or more sensors 226), the access control 220 (e.g., a control valve), or other flow adjusting features throughout the compressor 200. The control system 400 may be implemented as a distributed control system (DCS) or any computer-based workstation that is fully or partially automated. For example, the control system 400 can be any device employing one or more general purpose or application-specific processor (e.g., processor 228), which may generally be associated with memory circuitry (e.g., memory 230) for storing instructions such as exhaust processing parameters. As such, the processor 228 may include one or more processors, and the memory 230 may include one or more tangible, non-transitory, machine-readable media collectively storing instructions executable by the processor 228 to control the flow in the compressor 200, as illustrated in FIG. 4 and discussed below, via at least one control action 410 described herein.

[0048] In some embodiments, the control system 400 may operate the access control 220 via the actuator 222 to control an amount of flow passing through the vent path 218. In the illustrated embodiment, the control system 400 is communicatively coupled to and controls the access control 220 to enable automatic adjustment of the flow through the vent path 218. For example, during normal operating conditions, the control system 400 may provide instructions to close the access control 220 via the actuator 222 and block a refrigerant flow 202 into the vent path 218. In this situation, the compressed refrigerant flow 202 exiting the impeller 210 primarily flows through the diffuser 212 and into the discharge chamber 214 of the compressor 200. At a later time, the controller 224 may detect surge conditions indicative of an active or impending surge event, and the control system 400 may provide instructions to open the access control 220 via the actuator 222 and allow at least a portion of the refrigerantflow 202 into the vent path 218. Accordingly, the vent path 218 may route the portion of the refrigerant flow 202 to the suction chamber 208 without passing the impeller 210.

[0049] Furthermore, the control system 400 may also control the degree of opening of the access control 220 to adjust the amount of flow passing through the vent path 218. For example, the control system 400 may provide instructions to open the access control 220 to the substantially open position, wherein the refrigerant flow 202 is essentially unimpeded, to allow a maximum amount of flow to route from the diffuser 212 through the vent path 218 to the suction chamber 208. In other embodiments, the control system 400 may provide instructions to open the access control 220 to a certain position between the substantially open position and the completely closed position, such that an amount of flow equivalent to 50% of the maximum amount of flow may be route from the diffuser 212 through the vent path 218 to the suction chamber 208. The one or more sensors 226 may be disposed at one or more locations within the diffuser 212 and / or the discharge chamber 214 to analyze a controlled flow 402 and monitor its flow characteristics, such as a temperature and a pressure. The one or more sensors 226 may transmit data 404 via a signal 406 to the control system 400, wherein the data 404 may be indicative of the current flow characteristics. The control system 400 may adjust the access control 220 based on the flow characteristics monitored in the diffuser 212 and / or the discharge chamber 214. For example, if flow characteristics of the diffuser 212 is trending further away from the operating boundaries of the compressor 200 with the current degree of opening of the access control 220, the control system 400 may provide instructions to increase the degree of opening of the access control 220 such that a greater portion of the refrigerant flow 202 may enter the vent path 218 to mitigate the surge conditions.

[0050] Alternatively or additionally, the control system 400 may adjust the access control 220 based on a setpoint 408, which may include flow characteristics of a target normal operating flow, in addition to the data 404, which may include the current flow characteristics monitored in the diffuser 212 and / or the discharge chamber 214 (e.g., signal 406). In response to the signal 406 indicating that surge conditions are detected in the diffuser, the control system 400 may receive the setpoint 408 such that the control system 400 may perform the at least one control action 410 to control the flow in the diffuser 212 and / or the discharge chamber 214 to match the target normal operating flow. In some embodiments, the setpoint 408 may be provided manually by an operator of the compressor 200. In other embodiments, the setpoint 408 may be determined by the control system 400 based on historical sensor readingsindicative of flow characteristics of normal operating flows. The controller 224 then provides the actuator 222 instructions to adjust the degree of opening of the access control 220, determined to minimize the difference between the setpoint and the input signal from the one or more sensors 226. Accordingly, the current flow characteristics, as indicated by the data 404, in the diffuser 212 and / or the discharge chamber 214 may change as a result of adjusting the degree of opening of the access control 220. The control system 400 may continue adjusting the degree of opening following the at least one control action 410 described above until the flow in the diffuser 212 and / or the discharge chamber 214 matches the target normal operating flow7.

[0051] It should be noted that there may be additional access controls throughout the compressor 200 used to adjust different amounts and / or flows between the compressor components. The control system 400 may also provide instructions to a second access control disposed in the discharge chamber 214 to block or allow a reversed refrigerant flow7to route away from the impeller 210.

[0052] The control system 400 may use information provided via input signals to generate one or more output signals for the access control 220 and / or the second access control to control a reversed refrigerant flow within the compressor 200. Additionally or alternatively, the control system 400 of the compressor 200 may perform functions such as notifying the operators of the compressor 200 to adjust operating parameters, perform service, or otherwise cease operating the compressor 200 until the surge conditions within the compressor 200 is no longer active.

[0053] While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

[0054] The techniques presented and claimed herein are referenced and applied to material objects and concrete examples of a practical nature that demonstrably improve the present technical field and, as such, are not abstract, intangible or purely theoretical. Further, if any claims appended to the end of this specification contain one or more elements designated as “means for (performing (a function)... ” or “step for (perform)ing (a function)... ”, it is intended that such elements are to be interpreted under 35 U.S.C. 112(f). However, for anyclaims containing elements designated in any other manner, it is intended that such elements are not to be interpreted under 35 U.S.C. 112(f).

Claims

CLAIMS1 . A HVAC&R system, comprising: a refrigeration circuit configured to circulate refrigerant; a compressor disposed between a condenser and an evaporator along the refrigeration circuit, wherein the compressor is configured to receive and compress the refrigerant from the evaporator and direct the refrigerant from the compressor to the condenser; a housing of the compressor comprising a suction chamber configured to supply the refrigerant to an impeller of the compressor and a discharge chamber configured to receive the refrigerant from a diffuser of the compressor; and a vent system integrated with the housing of the compressor and configured to bypass the impeller to route the refrigerant from the diffuser to the suction chamber during surge conditions or impeding surge conditions.

2. The HVAC&R system of claim 1. wherein the vent system comprises a control valve configured to be actuated by a controller to open or block access to a vent path of the vent system.

3. The HVAC&R system of claim 2, comprising sensors disposed within the compressor to detect the surge conditions or the impeding surge conditions; wherein the controller configured to: open the control valve when the sensors indicate the surge conditions or the impeding surge conditions are present; and close the control valve when the sensors indicate the surge conditions or the impeding surge conditions are not present.

4. The HVAC&R system of claim 1, wherein the vent system comprises a barrier that is configured to actuate to control access of the refrigerant to a vent path extending from the diffuser to the suction chamber, wherein the barrier is calibrated to actuate during the surge conditions or the impeding surge conditions.

5. The HVAC&R system of claim 4, wherein the barrier comprises a biased valve or biased flap that is calibrated to open upon exposure to pressure levels associate with the surge conditions or the impeding surge conditions.

6. The HVAC&R system of claim 1, wherein the vent system comprises a vent path extending from the diffuser to the suction chamber with portals into or out of the vent path, wherein the portals are sized or positioned to resist flow through the vent path outside of the surge conditions or the impeding surge conditions.

7. The HVAC&R system of claim 1. comprising a controller and sensors positioned downstream of the impeller and configured to predict or detect the surge conditions or the impeding surge conditions based on a comparison of readings from the sensors and a surge map for the compressor.

8. The HVAC&R system of claim 1, wherein the vent system is configured to direct a portion of the refrigerant from the diffuser to the suction chamber during the surge conditions.

9. The HVAC&R system of claim 8, wherein the portion is insufficient to cause resultant force on a bearing system of the compressor to exceed a capacity limit of the beanng system.

10. The HVAC&R system of claim 1, wherein the vent system comprises a vent path configured to extend from a diffuser nozzle base plate of the compressor housing.1 1. The HVAC&R system of claim 1, wherein the suction chamber comprises a scroll cavity.

12. A compressor system for a HVAC&R system, the compressor comprising: a compressor housing; an impeller and a diffuser configured to compress refrigerant to provide compressed refrigerant; a suction chamber of the compressor housing configured to supply the refrigerant to the impeller; a discharge chamber of the housing configured to receive the compressed refrigerant from the diffuser; and a vent system integrated with the housing and configured to bypass the impeller to route the compressed refrigerant from the diffuser to the suction chamber during surge conditions or impeding surge conditions.

13. The compressor system of claim 12, wherein the compressor comprises one or more sensors configured to detect the surge conditions or the impeding surge conditions.

14. The compressor system of claim 13, comprising a controller configured to: receive sensor data from the one or more sensors; detect the surge conditions or the impeding surge conditions based on the sensor data; and upon detection of the surge conditions or the impeding surge conditions, open access to a vent path of the vent system, wherein the vent path is configured to route a portion of the refrigerant from the diffuser to the suction chamber.

15. The compressor system of claim 14, wherein the controller is configured to detect the surge conditions or the impeding surge conditions based on the sensor data by: utilizing a machine learning model, wherein the machine learning model is trained with historical sensor data of the compressor to predict the surge conditions or the impeding surge conditions.

16. The compressor system of claim 14, wherein the controller is configured to: receive additional sensor data from the one or more sensors; determine that the surge conditions or the impeding surge conditions are no longer present based on the additional sensor data; and upon the determination, block access to the vent path of the vent system.

17. The compressor system of claim 13, wherein the one or more sensors comprises a sensor configured to measure a resultant force on a bearing.

18. The compressor system of claim 17, wherein the bearing is a magnetic bearing.

19. The compressor system of claim 12, wherein the diffuser is a variable geometry diffuser.

20. A HVAC&R system, comprising: a refrigeration circuit configured to circulate refrigerant;a compressor disposed between a condenser and an evaporator along the refrigeration circuit, wherein the compressor is configured to receive and compress the refrigerant from the evaporator and direct the refrigerant from the compressor to the condenser; a housing of the compressor comprising a suction chamber configured to supply the refrigerant to an impeller of the compressor and a discharge chamber configured to receive the refrigerant from the impeller; and a vent system integrated with the housing of the compressor and configured to bypass the impeller to route the refrigerant from a diffuser to the suction chamber upon detection of conditions predictive of surge conditions.

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