Systems Comprising Pressure Exchangers, Associated Methods, and Associated Non-Transitory Machine-Readable Storage Media

Abstract

The method includes identifying, by a processing device, a first indication of an operating speed of a pressure exchanger of the heat transfer system. The method further includes determining a target opening value for a first valve based on the first indication of the operating speed of the pressure exchanger. An inlet of the first valve is coupled to a high-pressure outlet of the PX. The method further includes causing actuation of the first valve based on the target opening value.

Description

[Technical Field]

[0001] The present disclosure relates to the control of systems, and more particularly, to the control of refrigeration and heat pump systems that include pressure exchangers. [Background technology]

[0002] The system uses fluids at different pressures. The system uses pumps and / or compressors to increase the pressure of the fluids. The energy use of a fluid processing system may be dominated by the pumps and / or compressors that increase the pressure of the fluids.

[0003] The present disclosure is illustrated by way of example, but not by way of limitation, in the figures of the accompanying drawings. [Brief explanation of the drawings]

[0004] [Figure 1A] FIG. 1A is a schematic diagram of a fluid treatment system including a hydraulic energy transfer system, according to some embodiments. [Figure 1B] FIG. 1B is a schematic diagram of a fluid treatment system including a hydraulic energy transfer system, according to some embodiments. [Figure 2A] FIG. 2A is an exploded perspective view of a pressure exchanger (PX), according to some embodiments. [Figure 2B] FIG. 2B is an exploded perspective view of a pressure exchanger (PX), according to some embodiments. [Figure 2C] FIG. 2C is an exploded perspective view of a pressure exchanger (PX), according to some embodiments. [Figure 2D] FIG. 2D is an exploded perspective view of a pressure exchanger (PX), according to some embodiments. [Figure 2E] FIG. 2E is an exploded perspective view of a pressure exchanger (PX), according to some embodiments. [Figure 3A] FIG. 3A is a schematic diagram of a fluid processing system including a PX, according to some embodiments. [Figure 3B]FIG. 3B is a schematic diagram of a fluid processing system including a PX, according to some embodiments. [Figure 4A] FIG. 4A is a flow diagram illustrating a method for controlling a fluid processing system according to some embodiments. [Figure 4B] FIG. 4B is a flow diagram illustrating a method for controlling a fluid processing system according to some embodiments. [Figure 4C] FIG. 4C is a flow diagram illustrating a method for controlling a fluid processing system according to some embodiments. [Figure 5] FIG. 5 is a block diagram illustrating a computer system in accordance with certain embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0005] Embodiments described herein relate to the control of refrigeration and / or heat pump systems that include pressure exchangers (e.g., refrigeration systems, heat pump systems, pressure exchanger systems, fluid processing systems that include pressure exchangers, heat transfer systems, control systems for carbon dioxide (CO2) refrigeration systems integrated with rotary pressure exchangers, etc.). In particular, control modules are described for controlling, maintaining, regulating, etc., the operation of systems that include one or more pressure exchangers.

[0006] Systems may use fluids at different pressures. A system may have a fluid supply at a lower pressure and one or more portions of the system operating at a higher pressure. A system may include a closed loop, with various fluid pressures maintained in different portions of the loop. These systems may include hydraulic fracturing (e.g., fracking or fracing) systems, desalination systems, refrigeration systems, heat pump systems, energy generation systems, mud pump systems, slurry pump systems, industrial fluid systems, waste systems, fluid transport systems, etc. Pumps or compressors may be used to increase the pressure of fluids in such systems.

[0007] Traditionally, heat transfer systems (e.g., refrigeration systems, heat pump systems, reversible heat pump systems, etc.) use pumps or compressors to increase the pressure of a fluid (e.g., a refrigeration fluid such as carbon dioxide (CO), R-744, R-134a, hydrocarbons, hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), ammonia (NH), refrigerant mixtures, R-407A, R-404A, etc.). Traditionally, a separate pump or compressor mechanically coupled to a motor is used to increase the fluid pressure in the portion of the system that involves increasing the fluid pressure. Pumps and compressors, especially those operating at large pressure differentials (e.g., resulting in large pressure increases in the fluid), require large amounts of energy. Thus, traditional systems consume large amounts of energy to increase the fluid pressure (via the pump or compressor driven by the motor). Additionally, traditional heat transfer systems reduce the fluid pressure through expansion valves and / or heat exchangers (e.g., condensers and / or evaporators, etc.). Conventional systems inefficiently increase and decrease fluid pressure, which is wasteful in terms of the energy used to run the conventional systems (e.g., the energy used to repeatedly increase the pressure of the refrigeration fluid and cause the temperature of the surrounding environment to increase or decrease).

[0008] The disclosed systems, devices, and methods enable control of a system (e.g., a fluid processing system, a heat transfer system, a refrigeration system, a heat pump system, a cooling system, a heating system, etc.) that includes one or more pressure exchangers (PXs). In the system, the PXs can be configured to exchange pressure between a first fluid (e.g., a high-pressure portion of a refrigeration fluid in a refrigeration cycle) and a second fluid (e.g., a low-pressure portion of a refrigeration fluid in a refrigeration cycle). The PXs can receive the first fluid (e.g., a portion of the high-pressure refrigeration fluid) through a first inlet (e.g., a high-pressure inlet) and the second fluid (e.g., a portion of the low-pressure refrigeration fluid) through a second inlet (e.g., a low-pressure inlet). Upon entering the PX, the first fluid may be at a higher pressure than the second fluid. The PXs can exchange pressure between the first and second fluids. The first fluid may exit the PX through a first outlet (e.g., a low-pressure outlet), and the second fluid may exit the PX through a second outlet (e.g., a high-pressure outlet). Upon exiting the PX, the second fluid may have a higher pressure than the first fluid (eg, pressure has been exchanged between the first and second fluids).

[0009] In some embodiments, a heat transfer system (e.g., a refrigeration system, a heat pump system, etc.) may target controlled operating conditions. For example, a refrigeration system may target a specific temperature for a refrigeration zone (e.g., for safe storage of perishable materials such as food, medicine, scientific materials, or research materials), a heat pump system may target a comfortable internal temperature for a home, a system may target a heat exchange rate between the system and the environment, one or more portions of the system may target an operating temperature, pressure, fluid density, etc. The operating parameters for maintaining the target conditions may depend on many factors, such as ambient temperature, the mass, type, and initial temperature of materials in the temperature-controlled region, the frequency of material and / or energy exchange between the controlled region and the surrounding environment, etc.

[0010] In some embodiments, the PX may be capable of operating at various operating speeds. For example, a rotary PX may be capable of operating at various rotational speeds, a reciprocating PX may be capable of operating at various cycle frequencies, etc. The PX may be coupled to a motor. The motor may be configured to control the operating speed of the PX. The operating speed of the PX may affect fluid flow rates, fluid pressures, etc. in various portions of the fluid process system. In some embodiments, the motor may drive the PX; for example, if a faster flow rate is targeted through the PX, the motor may speed up the operation of the PX. In some embodiments, the motor may act to throttle the PX; for example, if a slower flow rate is targeted through the PX, the motor may throttle the PX to maintain the desired flow rate. A controller may be operably coupled to the motor of the PX. The controller may receive data collected from one or more portions of the fluid process system, for example, pressure data indicative of fluid pressure associated with (e.g., exiting) a condenser of the fluid process system, flow rate data indicative of the flow rate through a portion of the fluid process system, or the like. The controller may generate a control signal for the motor based on the received data indicative of one or more operating conditions of the fluid treatment system, and the motor may be configured to adjust the operating speed of the PX based on the control signal.

[0011] In some embodiments, the operating speed of the PX may be utilized to maintain one or more conditions of the fluid system. For example, the speed of the PX may be selected to maintain a target fluid pressure at a component upstream of the PX. The speed of the PX may further affect other conditions in the system but may be unavailable for regulation, at least in part, due to the effect of the speed of the PX on multiple conditions and components in the system. Additional control methods may be utilized to maintain one or more target conditions of the fluid system that may be further influenced by the operating speed of the PX.

[0012] In some embodiments, the fluid system may include one or more control valves that can open or close to allow a target fluid flow rate. The control valve may be included in the fluid system coupled to the high-pressure outlet of the PX. For example, fluid may exit the high-pressure outlet of the PX, pass through an auxiliary gas cooler, and be supplied to the control valve. The control valve may have an adjustable opening that is adjusted based on one or more inputs to maintain a target condition of the fluid system. The opening of the control valve may be adjusted to maintain a target travel distance of the PX.

[0013] The distance traveled is a measure of fluid flow into a duct of the PX. For example, a fluid may enter a duct through a first inlet and exchange pressure with a second fluid entering the duct through an inlet located on the opposite side of the duct. After exchanging pressure, the fluid may then be removed through an outlet located on the same side of the duct from which the fluid entered. The distance traveled is a measure of how far the first fluid flows into a duct before exiting through an outlet. The distance traveled indicates a volumetric flow rate through the PX based, for example, on the rotational speed of the PX, the number of ducts in the PX, and the total duct volume of the PX. The two inlets of the PX may have their own associated distance traveled. For example, during operation, the PX may operate with a first low-pressure distance traveled associated with the movement of a fluid supplied to the low-pressure inlet of the PX and a second high-pressure distance traveled associated with the movement of a fluid supplied to the high-pressure inlet of the PX. The distance traveled target may be selected based on a target volumetric flow rate through the PX, a target energy efficiency, a target pressure exchange efficiency, a target mixture of the first and second fluids, etc.

[0014] One or more travel distances of the PX can be adjusted and / or maintained by adjusting the operation of components of the fluid transfer system including the PX. For example, low-pressure inlet travel (e.g., the volume of liquid supplied to the PX low-pressure inlet compared to the working volume of the PX) can be maintained by adjusting the opening of a control valve coupled to the high-pressure outlet of the PX. The working volume of the PX depends on the operating speed of the PX. For example, in a rotary PX, as the rotational speed increases, the number of ducts of the PX utilized over a given period increases. The control valve may be configured to be controlled based on the speed of the PX to maintain a target low-pressure inlet travel distance within the PX. Additional signals can be considered in setting the opening of the control valve, such as the total system load (e.g., the total fluid flow rate through the system), the temperature in one or more gas coolers, etc.

[0015] In some embodiments, the fluid system may include a booster, compressor, or pump, e.g., a low-pressure booster, fluidly connected to the low-pressure inlet of the PX. The low-pressure booster may be configured to enable flow to the low-pressure inlet of the PX. The low-pressure booster may further affect the low-pressure inlet travel distance within the PX. In some embodiments, one or more parameters (e.g., parameters such as the operating speed of the PX, the target low-pressure inlet travel distance, the duct volume of the PX, and the operating volume of the low-pressure booster) may be used to set the operating speed of the low-pressure booster to achieve the target low-pressure inlet travel distance within the PX.

[0016] In some embodiments, the fluid system can control the flow of fluid to the low-pressure inlet of the PX via a control valve. In such cases, the fluid system may not include a low-pressure booster. In some embodiments, a bulk flow of fluid (e.g., a flow of primary heat transfer fluid, such as fluid passing through a main compressor, evaporator, gas cooler, condenser, etc.) can pass through a bulk flow channel of a heat exchanger. The heat exchanger may be positioned after the main gas cooler or main evaporator of a refrigeration system or heat pump system. A portion of the output of the bulk channel of the heat exchanger can pass through a cooling valve (e.g., a controlled expansion valve) and be supplied to a secondary channel of the heat exchanger to, for example, provide cooling to the bulk fluid passing through the bulk channel of the heat exchanger. A control valve can be used to synchronize the subcooling achieved in the heat exchanger with the bulk fluid flow. For example, the amount of fluid passing through the cooling valve can be increased to increase the cooling of the bulk fluid in the heat exchanger to achieve a target subcooling, a target temperature at the bulk outlet of the heat exchanger, etc. Achieving and / or maintaining a target fluid temperature, a target amount of fluid subcooling, etc. may improve the energy efficiency of the system, the heat transfer efficiency of the system, etc. A target temperature reduction across the heat exchanger may be achieved by adjusting the opening of a control valve to adjust the amount of cooling provided to the bulk fluid by the secondary fluid in the secondary channel of the heat exchanger.

[0017] In some embodiments, the booster-less system may further include a second control valve. The second control valve may be coupled to the high-pressure outlet of the PX, for example, after an auxiliary condenser or gas cooler. The second control valve may further influence the conditions of the fluid system. For example, the second control valve may be controlled based on the opening of the first control valve, the total system load, the temperature at the outlet of the bulk channel in the heat exchanger, etc.

[0018] The disclosed systems, devices, and methods offer advantages over conventional solutions. The disclosed systems reduce energy consumption compared to conventional systems. For example, the use of PXs in the disclosed heat transfer systems can recover energy stored as pressure and transfer that energy back into the system, thereby reducing the energy costs of operating the heat transfer system. Various controllers employed by the systems can increase the energy efficiency of the system, for example, by maximizing the transfer of pressure from a first fluid to a second fluid via the PXs (e.g., by adjusting fluid flow rate, fluid pressure, PX operating speed, etc.). The disclosed systems can reduce wear on components (e.g., pumps, compressors) compared to conventional systems. The introduction of PXs can reduce the pumping load on one or more pumps / compressors, for example, reducing the target pressure differential that the compressors must achieve. One or more controllers (e.g., control systems) may improve pump and compressor operation by protecting one or more system components (e.g., minimum feasible pumping speed) while allowing operation at a target pumping speed, e.g., a pumping speed selected to meet a target system output (e.g., maintain a target temperature in a heat transfer system). The disclosed systems can protect one or more components from damage. For example, a system compressor may be sensitive to the phase of the material fed to the compressor (e.g., configured to compress gas and may be damaged if fed with a liquid, etc.). The system controller can modify one or more operating parameters of the system (e.g., fluid flow rate, pumping speed, PX operating speed, control valve opening, etc.) to maintain the supply of gas to the compressor (e.g., by maintaining a gas superheat target). The disclosed systems can enable greater flexibility in component selection for fluid processing systems. For example, one or more controllers (e.g., control systems) may be operatively coupled and cooperate to maintain one or more operating conditions.For example, a system may include multiple controllers (e.g., control systems) operably coupled to multiple components (e.g., configured to facilitate adjustment of one or more operating parameters of the components). Multiple control signals may be generated to accomplish one or more goal tasks, such as maintaining the temperature of an area associated with a heat transfer system or maintaining the load on a pump within a target range. Utilizing multiple controllers in a system may make such goals achievable and / or allow a user to use a larger selection of components in the system (e.g., a system may include a pump with a small manufacturer-recommended operating pressure range, where the pressure at the pump can be maintained within that range for various operating conditions).

[0019] Although some embodiments of the present disclosure are described in connection with pressure exchangers, energy recovery devices, and hydraulic energy transmission systems, the present disclosure may be applied to other systems and devices (e.g., non-isobaric pressure exchangers, non-pressure exchanger rotating components, non-rotary pressure exchangers, systems that do not include pressure exchangers, etc.).

[0020] Although some embodiments of the present disclosure are described in connection with exchanging pressure between fluids used in fracking systems, desalination systems, heat pump systems, and / or refrigeration systems, the present disclosure may also be applied to other types of systems. Fluids may refer to liquids, gases, transcritical fluids, supercritical fluids, subcritical fluids, and / or combinations thereof.

[0021] In some aspects of the present disclosure, a method includes obtaining, by a processing device, a first indication of an operating speed of a PX of a heat transfer system. The method further includes determining a target opening of a first valve based on the first indication of the operating speed of the PX, where an inlet of the first valve is coupled to a high-pressure outlet of the PX. The method further includes generating a control signal based on the target opening. The method further includes causing actuation of the first valve to the target opening by providing the first control signal to the valve.

[0022] In some aspects of the present disclosure, a method includes obtaining, by a processing device, a first indication of an operating speed of a PX of a heat transfer system. The method further includes determining a target operating speed of a low-pressure booster based on the first indication of the operating speed of the PX, wherein an outlet of the low-pressure booster is coupled to a low-pressure inlet of the PX. The method further includes generating a first control signal based on the target operating speed of the low-pressure booster. The method further includes providing the first control signal to the low-pressure booster. The low-pressure booster is configured to adjust the operating speed of the low-pressure booster in view of the first control signal.

[0023] In some aspects of the present disclosure, a method includes acquiring first temperature data by a processing device. The first temperature data indicates a temperature difference between a fluid at a bulk fluid inlet of a heat exchanger and a fluid at a bulk fluid outlet of the heat exchanger. The outlet of the heat exchanger is coupled to a high-pressure inlet of the PX. The method further includes determining a target adjustment for a first valve coupled to the bulk fluid outlet of the heat exchanger and the secondary fluid inlet of the heat exchanger based on the first temperature data. The method further includes generating a first control signal based on the target adjustment. The method further includes providing the first control signal to the first valve. The first valve is configured to adjust an opening of the first valve in accordance with the target adjustment based on the first control signal.

[0024] In some aspects of the present disclosure, a non-transitory machine-readable storage medium stores instructions that, when executed, cause a processing device to perform any of the above methods. In some aspects of the present disclosure, a system includes a memory and a processing device coupled to the memory. The processing device is configured to perform any of the above methods. In some aspects of the present disclosure, a fluid treatment system includes a PX and a controller. The controller is configured to perform operations associated with maintaining target conditions of the fluid treatment system according to the above methods.

[0025] FIG. 1A illustrates a schematic diagram of a fluid treatment system 100A (eg, a heat transfer system) including a hydraulic energy transfer system 110, in accordance with certain embodiments.

[0026] In some embodiments, hydraulic energy transfer system 110 includes a pressure exchanger (e.g., PX). Hydraulic energy transfer system 110 (e.g., PX, a collection of components including PX, etc.) receives low-pressure (LP) in fluid 120 from LP in system 122 (e.g., via a low-pressure inlet). Hydraulic energy transfer system 110 also receives high-pressure (HP) in fluid 130 from HP in system 132 (e.g., via a high-pressure inlet). Hydraulic energy transfer system 110 (e.g., PX) exchanges pressure between HP in fluid 130 and LP in fluid 120 to provide LP out fluid 140 to LP out fluid system 142 (e.g., via a low-pressure outlet) and HP out fluid 150 to HP out fluid system 152 (e.g., via a high-pressure outlet). Controller 180 can cause regulation of the flow rates of HP in fluid 130 and LP out fluid 140 by one or more flow valves, pumps, and / or compressors (not shown). The controller 185 may be configured to cause various operations (e.g., of the controllable components 186). The controller 185 may be configured to cause the actuation of one or more valves. The controller 185 may be configured to cause the adjustment of the operating speed of one or more components. The controller 185 may cause other operations of the controllable components 186. The controller 185 may actuate one or more valves. The controller 185 may activate, deactivate, or adjust the operation of one or more pumps (e.g., adjust the operating speed of a booster pump).

[0027] In some embodiments, hydraulic energy transmission system 110 includes a PX for exchanging pressure between HPin fluid 130 and LPin fluid 120. In some embodiments, the PX is substantially or partially isobaric (e.g., an isobaric pressure exchanger (IPX)). The PX can be a device that transfers fluid pressure between HPin fluid 130 and LPin fluid 120 (e.g., without utilizing centrifugal techniques) with approximately 50%, 60%, 70%, 80%, 90%, or greater efficiency (e.g., pressure transfer efficiency, substantially isobaric). High pressure (e.g., HPin fluid 130, HPout fluid 150) refers to a pressure greater than low pressure (e.g., LPin fluid 120, LPout fluid 140). The LPin fluid 120 of the PX may be pressurized and exit the PX at a high pressure (e.g., HPout fluid 150, at a pressure higher than the pressure of the LPin fluid 120), and the HPin fluid 130 may be at least partially depressurized and exit the PX at a low pressure (e.g., LPout fluid 140, at a pressure lower than the pressure of the HPin fluid 130). The PX can operate with the HPin fluid 130 and pressurize the LPin fluid 120, with or without a fluid separator between the fluids. Examples of fluid separators that may be used with the PX include, but are not limited to, a piston, a bladder, a diaphragm, etc.

[0028] In some embodiments, the PX may be a rotary device. Rotary PXs, such as those manufactured by Energy Recovery Inc. of San Leandro, California, may not have separate valves, as effective valving is achieved internally through the relative motion of the rotor with respect to the end cover. In some embodiments, the rotary PX operates with internal pistons to isolate fluids and transmit pressure with relatively little mixing of the inlet fluid streams. In some embodiments, the rotary PX operates without internal pistons between the fluids.

[0029] In some embodiments, the PX may be a reciprocating device. A reciprocating PX may include a piston that moves back and forth within a cylinder to transfer pressure between fluid streams. For example, a reciprocating PX may include one or more pressure exchange chambers. Each pressure exchange chamber may include a piston. A high-pressure first fluid may enter one side of the pressure exchange chamber and transfer energy (e.g., via piston displacement) to a low-pressure second fluid on the other side of the pressure exchange chamber. The now-low-pressure first fluid may then be discharged from the pressure exchange chamber, while the now-high-pressure second fluid may be utilized for the operation of a fluid processing system (e.g., for desalination, fracking, refrigeration, heat transfer, etc.). The low-pressure second fluid may then fill the second side of the pressure exchange chamber, and the high-pressure first fluid may subsequently be introduced into the first side of the pressure exchange chamber to transfer energy to another portion of the second fluid. A reciprocating device may include multiple pressure exchange chambers that operate in cycles for a substantially continuous flow of the high-pressure second fluid from the device.

[0030] In some embodiments, PX may be a hydraulic turbocharger device. The hydraulic turbocharger PX may introduce a high-pressure first fluid into a chamber containing a first impeller. The high-pressure first fluid may rotate the impeller by transferring energy from the first fluid to the impeller. The first impeller may be coupled to a shaft, which may be further coupled to a second impeller in a separate chamber. Rotation of the first impeller may cause rotation of the second impeller. The second impeller may be in contact with a low-pressure second fluid. Rotation of the impeller may transfer energy to the second fluid (e.g., increase the pressure of the second fluid).

[0031] Any PX or multiple PXs may be used in the present disclosure, such as, but not limited to, a rotary PX, a reciprocating PX, a hydraulic turbocharger PX, or any combination thereof. Additionally, a PX may be located on a skid separate from other components of fluid treatment system 100A (e.g., in situations where a PX is being added to an existing fluid treatment system). For example, a PX may be fixed to a structure that can be moved from one location to another. A PX may be coupled to a system (e.g., system pipes, etc.) installed on-site. The structure to which a PX is fixed may be referred to as a "skid."

[0032] In some embodiments, the motor 160 is coupled to the hydraulic energy transmission system 110 (e.g., to the PX). In some embodiments, the motor 160 controls the speed of the rotor of the hydraulic energy transmission system 110 (e.g., to increase the pressure of the HPout fluid 150 or to decrease the pressure of the HPout fluid 150). In some embodiments, the motor 160 generates energy (e.g., acts as a generator) based on pressure exchange within the hydraulic energy transmission system 110. For example, a pressure differential (e.g., the difference between the pressures of the LPin fluid 120 and the HPin fluid 130) drives the rotation of the rotating PX, and the motor 160 can both introduce resistance to that rotation, slowing the rotation, and generate electricity. Alternatively, the motor can act to slow the PX without generating electricity.

[0033] The hydraulic energy transfer system 110 may include a hydraulic turbocharger or hydraulic pressure exchanger, such as a rotary PX. The PX may include one or more chambers and / or channels (e.g., 1-100) to facilitate pressure transfer between a first fluid and a second fluid (e.g., gas, liquid, multiphase fluid).

[0034] In some embodiments, hydraulic energy transmission system 110 can transfer energy (e.g., pressure) between two fluids that are substantially different in composition, phase, etc. For example, the PX of hydraulic energy transmission system 110 can transfer pressure between a first fluid (e.g., a pressure exchange fluid, such as a proppant-free fluid, a substantially proppant-free fluid, a lower viscosity fluid, a fluid containing less than a threshold amount of a particular chemical, etc.) and a second fluid that may have a higher viscosity (e.g., high viscosity), contain more than a threshold amount of a particular chemical (e.g., a corrosive chemical), and / or contain solid particles (e.g., fracking fluid containing sand, proppant, powder, debris, ceramic, etc.). By transferring energy from one type of fluid to another, expensive components, such as pumps, can be protected from contact with fluids that may be harmful to them, such as viscous, corrosive, or abrasive fluids.

[0035] In some embodiments, hydraulic energy transfer system 110 can transfer energy (e.g., pressure) between two fluids of substantially similar composition. For example, in some conventional systems, the system's waste stream may include a high-pressure fluid. Hydraulic energy transfer system 110 can accept the high-pressure waste stream as a high-pressure input (e.g., HPin fluid 130) and transfer energy from that stream to a low-pressure working stream (e.g., LPin fluid 120). In some systems, such as closed refrigeration systems, energy can be recovered from the high-pressure portion of the fluid stream to reduce pump and / or compressor demands on the fluid stream.

[0036] In some embodiments, the LPin system 122 includes a booster (e.g., a pump and / or a compressor) to increase the pressure of the fluid to form the LPin fluid 120 or to facilitate mass transfer of the fluid for supply to the hydraulic energy transfer system 110. In some embodiments, the LPin system 122 receives gas from the LPout system 142. In many embodiments, the LPin system 122 receives fluid from a receiver (e.g., a flash tank). The receiver can receive the LPout fluid 140 output from the hydraulic energy transfer system 110.

[0037] Fluid treatment system 100A further includes a control module 180. Control module 180 may include one or more controllers 185. Control module 180 may be configured to perform any of the methods of Figures 4A-C. Controller 185 of control module 180 may receive data (e.g., measurement data) from sensors associated with fluid treatment system 100A. Controller 185 may be configured to generate control signals based on operating parameters (e.g., thresholds, specified operating ranges, target parameter values, etc.) and / or data received from the sensors. Controller 185 may include a single device that performs one or more control tasks, a separate device for each control task (e.g., each controllable component of fluid treatment system 100A), or several devices for performing multiple functions each. For example, each operation of controller 185 may be performed by a separate device, or all operations of controller 185 may be performed by a single device, or a combination of separate combined devices may be employed. Components of control module 180 may include a general-purpose computing device, a personal computer (PC), a laptop, a mobile phone, a tablet computer, a netbook computer, a microcontroller, a dedicated controller (e.g., hardware, circuitry, etc.), a proportional-integral-derivative (PID) controller (e.g., a ternary control controller), a web appliance, or any other device capable of executing (sequentially or otherwise) a set of instructions that specify the actions that the device should take. There may be cases where control module 180 includes multiple controllers that act independently (e.g., without input from one controller to the other, without measurement data from a sensor being provided to multiple controllers).The control module 180 may include multiple controllers operating in conjunction with each other, for example, a target adjustment to an operating parameter of the fluid treatment system 110A (e.g., as reported by one or more sensors of the system) may include adjusting the operation of one or more components of the system by one or more controllers of the controller 180.

[0038] Fluid treatment system 100A may further include one or more sensors to provide sensor data (e.g., flow rate data, pressure data, velocity data, etc.) associated with the fluid in fluid treatment system 100A. Controller 185 may control one or more flow rates in fluid treatment system 100A, the operation of one or more components of fluid treatment system 100A (e.g., the operation of motor 160, the operation of one or more pumps), etc. based on the sensor data. In some embodiments, controller 185 actuates one or more flow valves based on the received sensor data.

[0039] The hydraulic energy transfer system 110 can be used in different types of systems, such as fracking systems, desalination systems, refrigeration systems (e.g., FIG. 1B), heat pump systems, slurry pump systems, industrial fluid systems, waste systems, and fluid transport systems.

[0040] The controller 185 of the control module 185 may provide control signals to interdependent components of the fluid treatment system 100A. For example, the controller 185 may provide a control signal to the motor 160 to control the operating speed of the hydraulic energy transfer system 110. The operating speed of the hydraulic energy transfer system 110 may further affect conditions at other locations in the fluid treatment system 100A. Other components, such as valves, pumps, etc., may operate to control conditions in the fluid treatment system 100A that are affected by the operating speed of the hydraulic energy transfer system 110. The controller 185 may provide signals to various controllable components 186 included in the fluid treatment system 100A. Various components of the subsystems of the fluid treatment system 100A may be controlled by signals provided by the controller 185 based on the operating speed of the hydraulic energy transfer system 110.

[0041] FIG. 1B shows a schematic diagram of a fluid treatment system 100B including a hydraulic energy transfer system 110, according to certain embodiments. Fluid treatment system 100B may be, for example, a heat transfer system, a refrigeration system, or a heat pump system. Fluid treatment system 100B may be configured to cool and / or heat an environment (e.g., an indoor space, a refrigeration unit, a freezer, etc.). In some embodiments, fluid treatment system 100B includes more components, fewer components, the same routing, different routing, and / or similar components than those shown in FIG. 1B. Some of the features in FIG. 1B that have similar reference numbers as those in FIG. 1A may have similar properties, functions, and / or structures as those in FIG. 1A.

[0042] The hydraulic energy transfer system 110 (e.g., PX) may receive LPin fluid 120 from an LPin system 122 (e.g., low-pressure lift device 128, low-pressure fluid pump, low-pressure booster pump, low-pressure compressor, low-pressure ejector, etc.) and may receive HPin fluid 130 from an HPin system 132 (e.g., condenser 138, gas cooler, heat exchanger). The hydraulic energy transfer system 110 (e.g., PX) may exchange pressure between the LPin fluid 120 and the HPin fluid 130, supply HPout fluid 150 to an HPout system 152 (e.g., high-pressure lift device 159, high-pressure fluid pump, high-pressure booster pump, high-pressure compressor, high-pressure ejector, etc.), and supply LPout fluid 140 to an LPout system 142 (e.g., evaporator 144, heat exchanger, etc.). The LPout system 142 (e.g., evaporator 144) may supply fluid to the compressor 178 and the low-pressure lift device 128. The evaporator 144 may supply fluid to the compressor 178 and / or the low-pressure lift device 128. In some embodiments, different components may supply fluid to the low-pressure lift device 128, the evaporator 144, etc. For example, the LPout fluid 140 may be supplied to a flash tank receiver. The liquid output from the flash tank may be supplied to the evaporator 144, and the gas output from the flash tank may be supplied to the low-pressure lift device 128. In some embodiments, additional valves, lines, pipes, fluid flow paths, etc. may supply fluid to different devices in different sequences and / or combinations. The condenser 138 may receive fluid from the compressor 178 and the high-pressure lift device 159. The controller 180 may control one or more components of the fluid treatment system 100B, including, for example, the motor 160 and various other controllable components 186. The high-pressure lift device 159 may be a high-pressure booster, and the low-pressure lift device 128 may be a low-pressure booster.

[0043] Fluid treatment system 100B may be a closed system, and LPin fluid 120, HPin fluid 130, LPout fluid 140, and HPout fluid 150 may all be fluids (e.g., refrigerant, the same fluid) that are circulated within the closed system of fluid treatment system 100B.

[0044] Fluid treatment system 100B may further include one or more sensors configured to provide sensor data associated with the system. For example, the sensors may report on properties of fluid at various stages of the system (e.g., various components of the system), such as temperature, pressure, flow rate, density, etc. The sensors may measure properties related to the function of fluid treatment system 100B; for example, a refrigeration system may include one or more temperature sensors that report on the temperature of an area being refrigerated. The sensors may measure properties that affect the operation of fluid treatment system 100B; for example, a heat transfer system intended to heat an area associated with condenser 138 may measure the temperature near evaporator 144; the temperature measurement near evaporator 144 may be used to modify one or more operating parameters of fluid treatment system 100B, for example, to achieve a target output (e.g., temperature), improve efficiency of operation, etc.

[0045] 4A-C. The controller 185 of the control module 180 may receive sensor data from the sensors (e.g., raw sensor data, pre-processed sensor data, average sensor data, data as a difference between a measurement and a target / threshold value, etc.). The controller 185 may be configured to generate one or more control signals based on the input sensor data. The control signals may facilitate operation of adjustable components of the fluid treatment system 100B.

[0046] Fluid treatment system 100B may include one or more valves with variable openings. For example, fluid flow rate may be changed by adjusting the opening of the valve. The valve may be electronically adjustable, for example, the valve may be an electronic expansion valve (EEV). The valve may be configured to adjust the opening (e.g., percentage opening value) of the valve based on a control signal received from control module 180. Fluid treatment system 100B may include one or more pumps, compressors, etc. The pumps and compressors may be configured to have variable operating speeds (e.g., motor operating speeds, pumping speeds, etc.). The pumps and compressors may be configured to adjust their operating speeds based on a control signal received from control module 180. Fluid treatment system 100B may include a motor 160 coupled to PX of hydraulic energy transfer system 110. Motor 160 may be configured to adjust the operating speed of PX based on a signal received from control module 180. For example, motor 160 may act as a generator by transferring rotational energy of PX to electrical energy.

[0047] 2A-E are exploded perspective views of a rotary PX 40 (e.g., a rotary pressure exchanger, a rotary liquid piston compressor (LPC)) according to certain embodiments. Some of the features in one or more of FIGS. 2A-E may have similar properties, functions, and / or structures as those in one or more of FIGS. 1A-B.

[0048] The PX 40 is configured to transfer pressure and / or work between a first fluid (e.g., refrigerant, particle-free fluid, proppant-free fluid, supercritical carbon dioxide, HPin fluid 130) and a second fluid (e.g., refrigerant, slurry fluid, fracking fluid, superheated gaseous carbon dioxide, LPin fluid 120) with minimal fluid mixing. The rotary PX 40 can include a generally cylindrical body portion 42 including a sleeve 44 (e.g., rotor sleeve) and a rotor 46. The rotary PX 40 can also include two end caps 48 and 50 that include manifolds 52 and 54, respectively. The manifold 52 includes a respective inlet port 56 and outlet port 58, while the manifold 54 includes a respective inlet port 60 and outlet port 62. During operation, the inlet ports 56, 60 allow the first and second fluids to enter the rotary PX 40 and exchange pressure, while the outlet ports 58, 62 allow the first and second fluids to exit the rotary PX 40. During operation, the inlet port 56 can receive a high-pressure first fluid (e.g., HPin fluid 130) output from the condenser, and after exchanging pressure, the outlet port 58 can be used to direct a low-pressure first fluid (e.g., LPout fluid 140) from the rotary PX 40 to a receiver (e.g., a flash tank) configured to receive the first fluid from the rotary PX 40. The receiver can form a chamber configured to separate the fluid into gas and liquid. Similarly, inlet port 60 may receive a low-pressure second fluid (e.g., low-pressure slurry fluid, LPin fluid 120) from a booster configured to receive a portion of the gas from the receiver and increase the pressure of the gas, and outlet port 62 may be used to direct a high-pressure second fluid (e.g., high-pressure slurry fluid, HPout fluid 150) out of rotary PX 40. End caps 48 and 50 include respective end covers 64 and 66 (e.g., end plates) disposed within respective manifolds 52 and 54, which enable fluid-sealing contact with rotor 46.

[0049] The ports of the PX are fluidly connected to a fluid system. The fluid system may include one or more controllable components 186. The controllable components 186 are fluidly connected to the PX, for example, by outlet ports 58 and 62. The controllable components 186 may include control valves, pumps, compressors, or the like. There may also be additional controllable components 186 that are not in direct fluid communication with the PX 40, such as one or more fans to provide additional heat transfer to or from a heat exchanger that is in fluid communication with the PX 40.

[0050] One or more components of PX40, such as rotor 46, end cover 64, and / or end cover 66, may be constructed from a wear-resistant material (e.g., carbide, cemented carbide, silicon carbide, tungsten carbide, etc.) having a hardness above a predetermined threshold (e.g., a Vickers hardness number of at least 1000, 1250, 1500, 1750, 2000, 2250, or greater). For example, tungsten carbide may be more durable and provide improved wear resistance to abrasive fluids compared to other materials, such as alumina ceramics. Additionally, in some embodiments, one or more components of PX40, such as rotor 46, end cover 64, end cover 66, and / or other sealing surfaces of PX40, may include inserts. In some embodiments, the insert may be constructed from one or more wear-resistant materials (e.g., carbides, cemented carbides, silicon carbide, tungsten carbide, etc.) having a hardness above a predetermined threshold (e.g., a Vickers hardness number of at least 1000, 1250, 1500, 1750, 2000, 2250, or greater) to provide improved wear resistance.

[0051] The rotor 46 may be cylindrical and disposed within the sleeve 44, allowing the rotor 46 to rotate about an axis 68. The rotor 46 may be described as having a plurality of channels 70 (e.g., ducts, rotor ducts) extending substantially longitudinally therethrough with openings 72 and 74 (e.g., rotor ports) at each end symmetrically disposed about the longitudinal axis 68. The openings 72 and 74 of the rotor 46 are positioned to be in hydraulic communication with inlet and outlet apertures 76 and 78 (e.g., end cover inlet and end cover outlet ports) and 80 and 82 (e.g., end cover inlet and end cover outlet ports) in the end covers 64 and 66, respectively, such that the channels 70 are exposed to high and low pressure fluids during rotation. As shown, the inlet and outlet apertures 76 and 78 and 80 and 82 may be designed in the form of arcs or segments of a circle (e.g., C-shaped).

[0052] In some embodiments, the control module 180 may be operatively coupled to the controllable components 186. In some embodiments, a single control module may be utilized to control some or all of the controllable components 186. In some embodiments, one or more of the controllable components 186 may have a dedicated corresponding control module 180. The control module 180 may be configured to implement any of the methods described in connection with FIGS. 4A-C. The control module 180 may receive sensor data (e.g., revolutions per minute measured via a tachometer or optical encoder, volumetric flow rate measured via a flow meter, pressure or temperature data of a fluid in a fluid processing system, etc.). The control module 180 may generate a control signal based on the sensor data. The control module 180 may use the control signal to regulate the operation of the controllable components 186.

[0053] The controllable components 186 may include one or more control valves. Controlling a control valve may include operating it to allow a target amount of fluid to pass through the control valve. The valve may be open to various sizes, a wide range of percentages, or the like. The control module 180 may, for example, generate control signals that operate valve actuators to move valve components to target positions to create a target opening for fluid flow.

[0054] The controllable components 186 may include one or more pumps, compressors, boosters, etc. The control module 180 may generate control signals that cause the pumps (including boosters, compressors, etc.) to achieve target operating speeds (e.g., RPM of the pump components), target pumping speeds, etc.

[0055] Control module 180 can determine target setpoints for one or more controllable components to maintain a target performance of the fluid system. For example, control module 180 can receive sensor data and generate control signals based on the sensor data to increase or decrease a characteristic of interest in the fluid system. Control module 180 may receive sensor data for the characteristic of interest, or may receive sensor data related to several characteristics of interest. For example, control module 180 may be configured to provide control signals to maintain a target travel distance of PX 40 (e.g., within a threshold error) based on pressures measured in various portions of the fluid system indicative of the travel distance of PX 40.

[0056] The operating speed of the PX 40 can be utilized to control the degree of mixing between the first and second fluids within the rotary PX 40, which can be used to improve the operability of a fluid treatment system (e.g., fluid treatment systems 100A-B of FIGS. 1A-B). For example, by varying the volumetric flow rates of the first and / or second fluids entering the rotary PX 40, an operator (e.g., a system operator, a plant operator) can control the amount of fluid mixing within the PX 40. Additionally, varying the rotational speed of the rotor 46 (e.g., via a motor) also allows the operator to control mixing. Three characteristics of the rotary PX 40 that affect mixing are (1) the aspect ratio of the rotor channel 70, (2) the exposure period between the first and second fluids, and (3) the creation of a barrier (e.g., a fluid barrier, piston, interface) between the first and second fluids within the rotor channel 70. First, the rotor channel 70 (e.g., a duct) is generally long and narrow, which stabilizes the flow within the rotary PX 40. Furthermore, the first and second fluids can move through the channel 70 in a plug flow regime with minimal axial mixing. Second, in certain embodiments, the speed of the rotor 46 reduces contact between the first and second fluids. For example, the speed of the rotor 46 (e.g., a rotor speed of about 1200 revolutions per minute (RPM)) can reduce the contact time between the first and second fluids to less than about 0.15 seconds, 0.10 seconds, or 0.05 seconds. Third, the rotor channel 70 (e.g., a small portion of the rotor channel 70) is used for pressure exchange between the first and second fluids. In some embodiments, a volume of liquid remains within the channel 70 as a barrier between the first and second fluids. All of these mechanisms can limit mixing within the rotary PX 40. Additionally, in some embodiments, the rotary PX40 may be designed to operate with an internal piston or other partition, either complete or partial, that separates the first and second fluids while still allowing pressure transmission.

[0057] In some embodiments, the operating speed of the PX may be set (e.g., to target the characteristics listed above or other characteristics of interest in the fluid system). The characteristics of the fluid system may be affected by the rotational speed of the PX 40. The control module 180 may receive an indication of the operating speed of the PX 40 (e.g., from a sensor, from a control signal for a controller of the PX 40, etc.) and may generate a control signal for the controllable component 186 based on the operating speed of the PX 40.

[0058] In some embodiments, control module 180 may receive an indication of the operating speed of PX40. The indication of the operating speed of PX40 may be provided by a sensor that measures the operating speed. The indication of the operating speed of PX40 may be provided by a control module for the motor of PX40 and may be based on the same information, such as a control signal for the speed of PX40. Based on the operating speed of PX40, control module 180 may provide a control signal to a control valve of controllable component 186. In response to the control signal, the control valve may adjust its opening to a target opening. In some embodiments, additional sensor data may be utilized, such as fluid temperature data, fluid pressure data, etc.

[0059] In some embodiments, control module 180 may receive an indication of the operating speed of PX 40. Based on the operating speed of PX 40, control module 180 can provide a control signal to a pump, such as a low-pressure booster pump. The pump can adjust its operating speed based on the control signal. The pump speed can be selected to achieve a target travel distance (e.g., LP-IN travel distance) for fluid supplied to the low-pressure inlet of PX 40. Additional indications can be considered in generating the control signal, such as gas cooler (e.g., heat exchanger) fluid temperature, gas cooler fluid pressure, etc.

[0060] In some embodiments, the control module 180 can receive temperature data of the temperature difference between the fluid at the bulk fluid inlet of the heat exchanger and the fluid at the bulk fluid outlet of the heat exchanger. A control signal can be generated by the control module 180 based on this temperature difference. The control signal can cause the actuation of a valve. The control signal can achieve a target value of subcooling of the bulk fluid within the heat exchanger.

[0061] 2B-2E are exploded views of an embodiment of the rotary PX 40, illustrating the sequence of positions of a single rotor channel 70 within the rotor 46 as the channel 70 rotates through a complete cycle. Note that FIGS. 2B-2E are simplified versions of the rotary PX 40 showing one rotor channel 70, and the channel 70 is shown as having a circular cross-sectional shape. In other embodiments, the rotary PX 40 may include multiple channels 70 having the same or different cross-sectional shapes (e.g., circular, oval, square, rectangular, polygonal, etc.). Thus, FIGS. 2B-2E are simplified versions for illustrative purposes, and other embodiments of the rotary PX 40 may have configurations different from those shown in FIGS. 2A-2E. As described in more detail below, the rotary PX 40 facilitates pressure exchange between a first fluid and a second fluid (e.g., a particle-free fluid and a slurry fluid, a higher-pressure refrigerant and a lower-pressure refrigerant, etc.) by allowing the first and second fluids to briefly contact each other within the rotor 46. In some embodiments, the PX facilitates pressure exchange between the first and second fluids by allowing the first and second fluids to contact opposite sides of a partition (e.g., a reciprocating partition, piston, not shown). In some embodiments, this exchange occurs at a rate that results in limited mixing of the first and second fluids. The speed of the pressure wave traveling through the rotor channel 70 (as soon as the channel is exposed to the aperture 76), the diffusion rate of the fluids, and / or the rotational speed of the rotor 46 can determine whether and to what extent mixing occurs.

[0062] 2B-E include a controllable component 186 fluidly connected to one or more outlets of PX 40. The controllable component 186 may be provided with a control signal according to any of the methods of FIGS. 4A-C. FIGS. 2B-E illustrate various operational stages of PX 40. The operation of PX 40 may be controlled by a control module, such as the control module 180 of FIGS. 1A-B. For example, the control module may be operably coupled to a motor of PX 40. The control module may send one or more control signals to the motor. The motor may regulate the operation of PX 40, e.g., the rotational speed of PX 40, the rotational speed of PX 40, etc. The control module may be operably coupled to other components of the fluid processing system that affect the operation of PX 40. For example, one or more compressors supplying fluid to PX 40 may be controlled by the control module, one or more valves supplying fluid to PX 40 may be controlled by the control module, one or more valves coupled to the outlets of PX 40 may be controlled by the control module, etc. These components may include the controllable components 186 of Figures 2B-E.

[0063] FIG. 2B is an exploded perspective view of an embodiment of a rotary PX 40 (e.g., a rotary LPC) according to certain embodiments. In FIG. 2B, a channel opening 72 is in a first position. In the first position, the channel opening 72 is in fluid communication with an aperture 78 in the end cover 64 and thus with the manifold 52, while the opposing channel opening 74 is in fluid communication with an aperture 82 in the end cover 66 and thus with the manifold 54. The rotor 46 can rotate in a clockwise direction, as indicated by arrow 84. In operation, a low-pressure second fluid 86 (e.g., a low-pressure slurry fluid) passes through the end cover 66 and enters the channel 70, where it contacts the first fluid 88 at a dynamic fluid interface 90. The second fluid 86 then drives the first fluid 88 out of the channel 70, through the end cover 64, and out of the rotary PX 40. However, because the contact duration is short, mixing between the second fluid 86 (e.g., a slurry fluid) and the first fluid 88 (e.g., a particle-free fluid) is minimal. In some embodiments, the low-pressure second fluid 86 contacts a first side of a partition (e.g., a piston, not shown) disposed within the channel 70, which is contacted by the first fluid 88 (e.g., on the opposite face of the partition). The second fluid 86 drives a barrier to push the first fluid 88 out of the channel 70. In such embodiments, mixing between the second fluid 86 and the first fluid 88 is negligible.

[0064] 2C is an exploded perspective view of an embodiment of a rotating PX 40 (e.g., a rotating LPC), according to certain embodiments. In FIG. 2C, channel 70 has rotated clockwise through an arc of approximately 90 degrees. In this position, opening 74 (e.g., outlet) is no longer in fluid communication with apertures 80 and 82 in end cover 66, and opening 72 is no longer in fluid communication with apertures 76 and 78 in end cover 64. Thus, a low-pressure second fluid 86 is temporarily contained within channel 70.

[0065] 2D is an exploded perspective view of an embodiment of a rotary PX 40 (e.g., a rotary LPC), according to certain embodiments. In FIG. 2D, the channel 70 has been rotated through an arc of approximately 60 degrees from the position shown in FIG. 2B. Now, the opening 74 is in fluid communication with the aperture 80 in the end cover 66, and the opening 72 of the channel 70 is now in fluid communication with the aperture 76 of the end cover 64. In this position, a first fluid 88 at high pressure enters and pressurizes a second fluid 86 at low pressure, driving the second fluid 86 through the aperture 80 and out of the rotor channel 70.

[0066] 2E is an exploded perspective view of an embodiment of a rotary PX 40 (e.g., a rotary LPC), according to certain embodiments. In FIG. 2E, channel 70 has rotated through an arc of approximately 270 degrees from the position shown in FIG. 2B. In this position, opening 74 is not in fluid communication with apertures 80 and 82 in end cover 66, and opening 72 is not in fluid communication with apertures 76 and 78 in end cover 64. Thus, first fluid 88 is no longer pressurized and is temporarily contained within channel 70 until rotor 46 rotates another 90 degrees and begins the cycle again.

[0067] Figures 3A-B are schematic diagrams of fluid processing systems 300A-B including a PX and one or more controllers (e.g., a control system, controller 185 of control module 180 of Figure 1A), according to certain embodiments. Some of the features in one or more of Figures 3A-B may have similar characteristics, functions, and / or structures (e.g., features having similar names and / or reference numbers) as those in one or more of Figures 1A-B and / or one or more of Figures 2A-E. One or more of the systems of Figures 3A-B may be used to implement one or more of the methods of Figures 4A-C.

[0068] 3A-B illustrate various fluid treatment system architectures (fluid treatment systems 300A-B) and various controllers according to certain embodiments. The illustrated architectures are example architectures; for example, the illustrated architectures highlight the operation of the controllers of the fluid treatment systems. Any of the controllers illustrated in FIGS. 3A-D may be included in any combination in any architectural design of a fluid treatment system. For example, a controller performing operations like controller 390 of FIG. 3A may be included in an architecture that does not include a low-pressure booster pump (e.g., the architecture shown in FIG. 3B), a controller performing operations like controller 394 controlling the bypass valve of FIG. 3B may be included in an architecture similar to that shown in FIG. 3A, etc. Fluid treatment systems including any of the controllers illustrated herein (e.g., any controller that adjusts the operation of components of the fluid treatment system and / or energy transfer system, including the PX, based on sensor data from the system), alone or in any combination, are within the scope of the present disclosure. The controllers may be separate components (e.g., each controller may be a separate device), the controllers may be combined components (e.g., the operations of two or more controllers may be performed by the same device, control system), etc. The controllers may provide control signals in response to various inputs, e.g., in response to sensor data provided to the controller. The controllers may provide control signals to adjust characteristics of the fluid process system, e.g., to adjust one or more condition values ​​of the fluid process system so that the condition values ​​satisfy one or more threshold conditions.

[0069] In some embodiments, the devices of the fluid treatment systems 300A-B of Figures 3A-3B can communicate via wired connections. In some embodiments, the devices of the fluid treatment systems 300A-B can communicate wirelessly. In some embodiments, the devices shown in Figures 3A-3B can communicate via a network. For example, the controllers of Figures 3A-3B can receive sensor data via a network and send control signals via a network. In some embodiments, the devices of the fluid treatment systems 300A-B of Figures 3A-3B can communicate via one or more wired networks. In some embodiments, the devices of the fluid treatment systems 300A-3B of Figures 3A-3B can communicate via one or more wireless networks (e.g., personal area networks, wireless local area networks, etc.). In some embodiments, the devices of the fluid treatment systems 300A-B can communicate via some wired networks and some wireless networks.

[0070] In some embodiments, the controllers of the fluid treatment systems 300A-B may be PID controllers. The controllers of the fluid treatment systems 300A-B may calculate an error value (e.g., the difference between a target setpoint and a measured value). The controllers of the fluid treatment systems 300A-B may apply a correction (e.g., generate a control signal) based on a proportional term, an integral term, and a derivative term of the error value. For example, the proportional term may be based on the difference between the setpoint value and the measured value, the integral term may be based on a past value of the error term integrated over time, and the derivative term may be based on a predicted future trend of the error term based on a current rate of change of the error term. In some embodiments, the controllers of the fluid treatment systems 300A-B may be computing devices. The controllers of the fluid treatment systems 300A-B may be implemented as software (e.g., executed by a general-purpose computing device), hardware, or a combination of hardware and software. In some embodiments, operation of the controllers of the fluid treatment systems 300A-B may include receiving one or more adjustable settings, parameters, etc. For example, the response of the controller (e.g., the magnitude of the output signal, the value of the adjustment command included in the control signal, etc.) may be of variable magnitude (e.g., for a given difference between a measured value and a target value of the measured characteristic, the controller may have a range of possible output values, and one implementation of the range of outputs may be a function of one or more settings and / or parameters of the controller). In some embodiments, the controller may have an associated lookup table, and for a given input (e.g., the difference between a set point and a measured value), the controller may generate an output according to the table. In some embodiments, the controller may perform calculations involving adjustable parameters (e.g., user-adjustable parameters, adjustable settings, etc.), and in response to the input, the controller may generate an output based on the input. In some embodiments, the parameters and / or settings of the controller may be selected / adjusted by a user.In some embodiments, the parameters and / or settings of the controller may be adjusted by a computer-implemented method, such as a computer-implemented method of the controller's associated computing device.

[0071] In some embodiments, the performance of the controller may be tracked (e.g., measured and stored for analysis over time). If the controller causes overshoot above a threshold (e.g., the percentage difference between the initial value and the target value exceeds a threshold, such as the frequency and / or severity of the overshoot) (e.g., if a component of the fluid processing system overcorrects in response to receiving a control signal from the controller, if a measured characteristic value passes through a target value before falling within the target value threshold, etc.), the sensitivity of the controller (e.g., the strength of the response to a measurement that differs from the target characteristic value) may decrease. For example, the controller may generate a control signal in response to receiving a measurement that differs from the setpoint (e.g., the difference between the setpoint and a measurement that exceeds a threshold). The controller may later receive a measurement that differs from the setpoint but in the opposite direction (e.g., the control signal may be intended to correct a measurement that is lower than the setpoint, but a subsequent measurement is higher than the setpoint). The responsiveness of the controller (e.g., parameters of a calculation determining the magnitude of the output relative to an input difference between a setpoint and a measurement, table entries determining the severity of an action commanded in a control signal based on input from a sensor, etc.) may be adjusted to reduce the likelihood of overshoot in future operations. Adjustments to controller settings may be global, e.g., parameters or tables may be updated and all future control signals may be generated according to the update. Adjustments to controller settings may not be applied globally, e.g., one or more lookup table values ​​may be adjusted while other lookup table values ​​are left unadjusted (e.g., lookup table values ​​associated with a range of differences between the setpoint and the measurement may be adjusted, lookup table values ​​associated with one or more differences relative to a range of measurement values ​​may be adjusted, etc.), parameters may be updated for use in certain situations (e.g., a list of parameters may apply to different measurements, different setpoint values, different values ​​of difference between the measurement and the setpoint, etc.), etc.

[0072] Similarly, if the controller is not sensitive enough (e.g., if a characteristic value in the system reaches a value within a threshold of a target value more slowly than desired), the controller's response may be increased. For example, the controller may receive a measurement that differs from a setpoint (e.g., the controller may be configured to receive a pressure measurement from a pressure gauge and receive a measurement that differs from the setpoint pressure value by at least a threshold amount). The controller may generate a control signal in response to receiving the measurement (e.g., the controller may generate a control signal for a valve to open to regulate the pressure at the pressure gauge). The controller may subsequently receive a measurement that the pressure has not reached the setpoint (e.g., the action taken by the valve in response to the control signal was not sufficient to reduce the difference between the setpoint and the measurement below the threshold). One or more settings / parameters of the controller may be adjusted to increase the controller's response to the input (e.g., increasing the output signal generated based on an input signal of a given strength, increasing the severity of the command included in the control signal associated with a given difference between the setpoint and the measurement, etc.).

[0073] In some embodiments, determining updates to the sensitivity and / or response of the controller (e.g., updates to parameters or settings governing the magnitude or severity of the output) may be performed by a machine learning model. The machine learning model may be trained using inputs including target characteristic values, measured characteristic values, responses of the controller (e.g., control signals), and / or results of system components acting on commands received by the controller. Once trained, the machine learning model may be configured to receive measured characteristic values ​​and target values ​​as inputs and generate an indication of appropriate action (e.g., control signals) to be taken by one or more components of the fluid process system as output. For example, the machine learning model may be provided with historical data as training data. The machine learning model may be provided with one or more historical characteristic values ​​associated with a characteristic to be corrected in the fluid process system (e.g., one or more setpoint values ​​and one or more measurements generated before and after a system component performs an action commanded by the controller) as training inputs. The machine learning model may further be provided with historical characteristic values ​​after adjustments have been made to correct the measured characteristic values ​​(e.g., one or more measurements taken after a control signal is generated for one or more components of the system). The machine learning model may be provided with one or more historical control signals (or data indicative of the control signals) as target outputs. Once trained, the machine learning model can receive as input current property values ​​(e.g., one or more setpoint values, one or more measured values, etc.) and generate as output control signals (or data associated with the control signals) that are predicted to bring the one or more measured property values ​​within a threshold difference value of the one or more setpoint values.

[0074] The fluid treatment systems 300A-B may be heat transfer systems. The fluid treatment systems 300A-B may be refrigeration systems. The fluid treatment systems 300A-B may be heat pump systems. The fluid treatment systems 300A-B may be reversible heat pump systems. The reversible heat pump systems may include components not shown in FIGS. 3A-B, such as reversing valves (e.g., four-way valves that reverse flow). The reversible heat pump systems may reverse the direction of flow of refrigerant fluid in one or more portions of the fluid treatment system, such as reversing flow through a condenser and / or evaporator (e.g., an outdoor heat exchange unit and / or an indoor heat exchange unit). The reversible heat pump systems may not reverse the direction of flow in one or more portions of the fluid treatment system, such as reversing flow through a compressor or pump. The reversible heat pump systems may include additional flow paths, additional valves, etc., utilized when reversing flow. Additional components and flow paths associated with a reversible heat pump system are not shown in Figures 3A-B, but reversible heat pump systems including such components are within the scope of this disclosure.

[0075] 3A is a schematic diagram of a fluid processing system 300A including a PX 310 and controllers 390, 391, 392, and 393, according to some embodiments. System 300A may be configured to control various components of the system based on sensor data received from sensors in the system. System 300A may be configured to determine the opening of one or more valves based at least in part on the operating speed of PX 310. System 300A may be configured to determine the operating speed of one or more pumps (e.g., low-pressure booster 314) based at least in part on the operating speed of PX 310.

[0076] PX310 may be a rotary pressure exchanger. In some embodiments, PX310 is an isobaric or substantially isobaric pressure exchanger. PX310 may be configured to exchange pressure between a first fluid and a second fluid. PX310 may be configured to exchange pressure between a first fluid at high pressure (e.g., supplied to PX310 at a high-pressure inlet labeled HP-IN) and a second fluid at low pressure (e.g., supplied to PX310 at a low-pressure inlet LP-IN). PX310 may reduce the pressure of the first fluid (e.g., with respect to output from PX310 at a low-pressure outlet LP-OUT) and increase the pressure of the second fluid (e.g., with respect to output from PX310 at a high-pressure outlet HP-OUT). In some embodiments, PX310 is coupled to a motor (e.g., rotation of a rotor of PX310 is controlled and / or regulated by the motor). In some embodiments, a controller (e.g., controller 390, controller 391, controller 392, controller 393) receives sensor data from one or more sensors. The controller may receive sensor data from one or more sensors and generate one or more control signals based on the received sensor data. In some embodiments, the mass flow rate (e.g., mass flow rate of a first fluid, mass flow rate of a second fluid, etc.) through the PX 310 may be related to the operating speed of the PX 310 (e.g., the rotational speed of the rotor of a rotary PX). In some embodiments, the pressure of the fluids (e.g., first fluid, second fluid, etc.) in various components of a fluid processing system (e.g., fluid processing systems 300A-B) may be related to the operating speed of the PX 310.

[0077] In some embodiments, the PX 310 is configured to receive a first fluid at high pressure (e.g., HPin fluid 130 in FIGS. 1A-B) via a high-pressure inlet. In some embodiments, the PX 310 is configured to receive a second fluid at low pressure (e.g., LPin fluid 120 in FIGS. 1A-B) via a low-pressure inlet. While references are made to "high pressure" and "low pressure," "high pressure" and "low pressure" may be relative to one another and may not involve specific pressure values ​​(e.g., the pressure of the HPin fluid 130 is higher than the pressure of the LPin fluid 120). The PX 310 may exchange pressure between the first and second fluids. The PX 310 may supply a first fluid via a low-pressure outlet (e.g., LPout fluid 140) and a second fluid via a high-pressure outlet (e.g., HPout fluid 150). In some embodiments, the first fluid supplied via the low-pressure outlet is at low pressure, and the second fluid supplied via the high-pressure outlet is at high pressure. PX310 may act as a high-pressure expansion valve, e.g., fluid flowing through PX310 (e.g., from a high-pressure inlet to a low-pressure outlet) may expand. PX310 may transfer pressure from one fluid stream to another, increasing the pressure of one fluid stream. PX310 may function as both an isentropic (or substantially isentropic) expansion device and a compressor, which may cause heat transfer, facilitate one or more operations of a refrigeration cycle, etc. The compression process of PX310 may be substantially isenthalpic.

[0078] In some embodiments, the first fluid may be a refrigerant fluid in a supercritical state (e.g., supercritical CO2). In some embodiments, the first fluid may be a refrigerant fluid in a liquid state (e.g., liquid CO2). In some embodiments, the second fluid may be a refrigerant fluid in a gaseous state (e.g., gaseous CO2). In some embodiments, the second fluid may be a refrigerant fluid in a two-phase mixture (e.g., a gas-liquid mixture of CO2). In some embodiments, the second fluid may be a refrigerant fluid in a liquid state (e.g., liquid CO2).

[0079] In some embodiments, fluid processing system 300A includes a main gas cooler 329 (e.g., a condenser), an auxiliary gas cooler 327, an evaporator 318, and a main compressor 322. In some embodiments, main gas cooler 329 and / or auxiliary gas cooler 327 may or may not function as a condenser; for example, the fluid processing system may operate at pressures and temperatures such that fluid condenses in the gas cooler. Any embodiment discussed herein may include a gas cooler, which may or may not act as a condenser in one or more applications. In some embodiments, for example, above the critical point of a fluid, the thermodynamic distinction between the gas and liquid states of the fluid disappears, and the fluid (e.g., the fluid in the condenser) may exist in a supercritical state (e.g., both the input and output fluids of the condenser may be in a supercritical state, either the input or output fluid of the condenser may be in a supercritical state, or neither fluid may be in a supercritical state, etc.). In some embodiments, fluid treatment system 300A is a refrigeration system. For example, evaporator 318 can facilitate absorption of heat by system 300A from a heat source (e.g., a refrigeration zone, a cold reservoir, etc.) into a refrigerating fluid. The heat may be rejected to a heat sink (e.g., the environment, a hot reservoir, etc.) via main gas cooler 329 and / or auxiliary gas cooler 327. In some embodiments, the refrigerating fluid facilitates heat transfer from the environment associated with evaporator 318 to the environment associated with main gas cooler 329. Main compressor 322 of fluid treatment system 300A can increase the corresponding pressure of the refrigerating fluid along a flow path between evaporator 318 and main gas cooler 329. In some embodiments, the refrigerating fluid is CO2 or other refrigerating fluid. The refrigerating fluid can flow substantially in a cycle (e.g., from gas cooler 329 to PX 310 to evaporator 318 to main compressor 322 to gas cooler 329, etc.).

[0080] In some embodiments, fluid treatment system 300A is a heat pump system. For example, in main gas cooler 329, the fluid may reject heat into a target area to be heated (e.g., to heat the interior space of a building). Heat may be absorbed from the environment by the fluid in fluid treatment system 300A in evaporator 318 and transferred to the environment of main gas cooler 329. In some embodiments, fluid treatment system 300A may be a reversible heat pump.

[0081] In some embodiments, fluid treatment system 300A includes a low-pressure booster (e.g., LP booster 314) and / or a high-pressure booster (not shown). Both LP booster 314 and HP booster may be configured to increase (e.g., “boost”) the pressure of a second fluid. For example, LP booster 314 may increase the pressure of a first fluid output from evaporator 318 (e.g., evaporator 318 may receive a low-pressure second fluid from PX 310 and output the fluid to LP booster 314). The HP booster may increase the pressure of a second fluid output by PX 310 via a high-pressure outlet. The second fluid may be communicated from HP-OUT of PX 310 to auxiliary gas cooler 327 and, in turn, to flash tank 313. The second fluid may be communicated to flash tank 313 via auxiliary high-pressure valve 368. Auxiliary high pressure valve 368 may be a control valve and may be configured, for example, to be set to a wide range of openings to allow control of the flow of fluid through the valve. Alternatively, a second fluid may be provided to combine with the fluid output from main compressor 322 (e.g., upstream of the inlet of main gas cooler 329) and provided to main gas cooler 329. LP booster 314 may be configured to increase pressure below a threshold (e.g., LP booster 314 may operate across a pressure differential below a threshold amount, fluid processing system 300A may transfer pressure through PX 310 to reduce the pressure differential at LP booster 314, etc.). For example, the LP booster 314 may increase the pressure of the second fluid by about 10-100 psi (about 68.9-689.5 kPa), about 30-80 psi (about 206.8-551.6 kPa), about 40-60 psi (about 275.8-413.7 kPa), about 50 psi (about 344.7 kPa), any range included therein, etc. The second fluid may experience a pressure loss (e.g., parasitic loss) as the second fluid flows from the LP booster 314 to the second inlet (e.g., low pressure inlet) of the PX 310.The LP booster 314 may be configured to increase the pressure of the fluid to a target value, e.g., a value selected for system operation, to a value associated with other pressures in the system (e.g., the pressure of the fluid associated with the low pressure outlet of the PX).

[0082] The HP booster can increase the pressure of the second fluid between the second outlet of the PX 310 and the inlet of the main gas cooler 329 or the auxiliary gas cooler 327. The HP booster can increase pressures less than a threshold (e.g., the HP booster can operate across a small pressure differential). For example, the HP booster can increase the pressure of the second fluid by approximately 10-100 psi (approximately 68.9-689.4 kPa), approximately 30-80 psi (approximately 206.8-551.6 kPa), approximately 40-60 psi (approximately 275.8-413.7 kPa), approximately 50 psi (approximately 344.7 kPa), any range therein, etc. The HP booster can increase the pressure of the second fluid to the inlet pressure of the associated gas cooler. The HP booster can increase the pressure of the fluid to a target value (e.g., a value selected for system operation, a measured pressure value corresponding to the output of the main compressor 322, etc.). In some embodiments, the HP booster can be coupled to the outlet of the gas cooler / condenser. In some embodiments, the fluid exiting the gas cooler is in a liquid state. Thus, in some embodiments, the HP booster pumps the liquid from the outlet of the gas cooler (e.g., the liquid exiting the gas cooler) to the high-pressure inlet of the PX310. The HP booster can increase the pressure of the liquid output from the condenser to the high-pressure inlet of the PX310.

[0083] In some embodiments, the main compressor 322 increases the pressure of the fluid by more than a threshold amount (e.g., the main compressor 322 operates at a pressure differential greater than a threshold amount, i.e., a pressure differential greater than the pressure differential at which the booster 314 operates, etc.). For example, the main compressor 322 may increase the pressure of the fluid by approximately 100-1200 psi (approximately 689.5-8273.7 kPa), approximately 500-1100 psi (approximately 3447.4-7584.2 kPa), approximately 800-1000 psi (approximately 5515.8-6894.8 kPa), approximately 900 psi (approximately 6205.3 kPa), at least 100 psi (approximately 689.5 kPa), at least 500 psi (approximately 3447.4 kPa), any included range, etc. In some embodiments, the operation of main compressor 322 may be performed by multiple physical devices, such as multiple compressors, multiple pumps, etc. The multiple compressors performing the operation of main compressor 322 may be arranged in parallel, series, or a combination of arrangements. Any discussion of main compressor 322 may be generalized to include multiple devices, such as by summing the energy consumed or calculating the total fluid flow rate through the compressor system, taking into account the location, specifications, and operating speed of each compressor in the compressor system.

[0084] Fluid treatment system 300A may include one or more sensors that measure characteristics associated with the system. For example, one or more temperature sensors may measure the temperature of the flowing fluid, the environment, or hot and / or cold sinks associated with the system. One or more pressure gauges may measure the pressure of the fluid in fluid treatment system 300A. One or more flow meters may measure the flow rate (e.g., mass flow rate) of the fluid through fluid treatment system 300A. One or more densitometers (e.g., two-phase fluid densitometers, two-phase densitometers, etc.) may measure the density of the fluid in fluid treatment system 300A. Other sensors (e.g., meters) may measure additional characteristics, such as work performed by various components, heat flow through the system, power consumed by system components, total fluid flow through various portions of the system, etc. Shown in FIG. 3A are gauge 380 and gauge 384.

[0085] Fluid treatment system 300A includes controllers 390, 391, 392, and 393. The controllers of fluid treatment system 300A may be PID controllers. The controllers of fluid treatment system 300A may perform actions based on known relationships between sensor data and control outputs, for example, via look-up tables, functional forms of the relationships, etc.

[0086] Controller 390 is operably coupled to PX 310. Controller 390 may receive one or more measurements from gauge 380. Controller 390 may receive fluid pressure measurements from gauge 380. Controller 390 may receive measurements as raw measurement data, preprocessed measurement data, averaged (e.g., boxcar averaged) measurement data, etc. In some embodiments, controller 390 may receive additional measurement data, for example, from one or more other sensors associated with fluid treatment system 300A. Controller 390 may receive ambient temperature data, for example, ambient temperature data of an environment near main gas cooler 329 and / or auxiliary gas cooler 327 (e.g., in the case of a refrigeration system) or ambient temperature data of an environment near evaporator 318 (e.g., in the case of a heat pump system). Controller 390 may receive sensor data from PX 310, such as data indicative of the operating speed of PX 310. Controller 390 may be configured to generate one or more control signals based on the received measurement data. The controller 390 may provide control signals to devices configured to regulate the operating speed of the PX 310, such as a motor coupled to the PX 310 (eg, coupled to a rotor of the PX 310).

[0087] The motor or other speed regulating device may be configured to adjust the operation of the PX 310 (e.g., by adjusting the operating speed of the motor) in response to receiving a control signal from the controller 390. The gauge 380 may provide an indication of the pressure of the fluid in the main gas cooler 329. The controller 390 may generate control signals directed to achieving and / or maintaining a target pressure of the main gas cooler 329. The target pressure of the main gas cooler 329 may be modified by the ambient temperature (e.g., a heat sink temperature for rejected heat) to achieve, for example, optimal energy efficiency, heat transfer, refrigeration, etc. For example, increasing the operating speed of the PX 310 may increase the flow rate of fluid through the PX 310. Increasing the operating speed of the PX 310 may decrease the fluid pressure in the main gas cooler 329, such as the pressure measured by the gauge 380.

[0088] In some embodiments, the target pressure of the main gas cooler 329 may be selected to maximize heat transfer in the system, maximize heat transfer between the main gas cooler 329 and the environment, maximize the energy efficiency of the system, maximize the coefficient of performance (COP, e.g., the ratio of heat transferred by the system to the power consumed by the system's pumps / compressors), etc.

[0089] In some embodiments, a device for regulating the speed of the PX may act to move, operate, or accelerate the PX 310. For example, a motor may drive the PX 310. The motor may draw power from a power source to drive the PX 310. In some embodiments, the motor may act like a generator. For example, the PX 310 may be driven by fluid in the fluid processing system 300A (e.g., driven by a pressure differential in the fluid, driven by one or more pumps and / or compressors in the system, etc.). The motor may provide additional resistance to the operation of the PX 310 (e.g., resistance to rotation of the rotor of a rotary PX), reducing the operating speed of the PX 310. The motor may generate power (e.g., convert the rotational energy of the PX 310 into electrical energy).

[0090] The controller 391 is operably coupled to the auxiliary cooling component 302. The auxiliary cooling component 302 may be a device configured to increase heat transfer between the auxiliary gas cooler 327 and the ambient environment. For example, the auxiliary gas cooler 327 may reject heat to the ambient atmosphere, and the cooling component 302 may be a fan that increases the transfer of heat from the auxiliary gas cooler 327 to the atmosphere. The auxiliary cooling component 302 may be a heat exchanger coupled to the auxiliary gas cooler 327, or may be another type of component that increases heat transfer away from the auxiliary gas cooler 327.

[0091] In some embodiments, the controller 391 can receive data measurements from the gauge 384. The gauge 384 can provide a temperature measurement of the fluid temperature of the auxiliary gas cooler 327. The gauge 384 can provide a temperature measurement of the fluid temperature of the fluid output from the auxiliary gas cooler 327. The controller 391 can generate a control signal based on the data provided by the gauge 384. The controller 391 can generate the control signal to achieve a target temperature of the fluid output by the auxiliary gas cooler 327. The controller 391 can generate the control signal to adjust the operation of the auxiliary cooling component 302. For example, the controller 391 can adjust the operating speed of a fan to achieve a target temperature (e.g., within a threshold) of the fluid at the outlet of the auxiliary gas cooler 327.

[0092] The controller 392 is operably coupled to the auxiliary high-pressure valve 368. The controller 392 can receive a signal from the PX 310 indicative of the operating speed of the PX 310. The signal from the PX 310 can be a signal from a sensor that measures the operating speed of the PX 310. The signal from the PX 310 can be a signal from a component of the PX 310 or a signal from a component coupled to the PX 310, such as a motor of the PX 310. The signal indicative of the operating speed of the PX 310 can be provided by the controller 390; for example, a control signal can be provided to the PX 310 to regulate the operation of the PX 310, or the control signal can be provided to the controller 392 for use by the controller 392 in further operation.

[0093] The controller 392 can generate a control signal for the auxiliary high-pressure valve 368 based on the operating speed of the PX 310. The auxiliary high-pressure valve can open or close to a target opening size or value. The target opening size may be selected to achieve a target travel distance for fluid within the PX 310. For example, the target opening size may be selected to achieve a target LP-IN travel distance for fluid supplied to the low-pressure inlet of the PX. Travel distance may be or include a measurement of the flow rate through the PX 310 compared to the operating volume of the PX 310 (e.g., duct volume, duct volume modified by operating speed, etc.). Travel distance may describe the portion of the operating volume of the PX 310 that is filled or displaced by the incoming fluid. The travel distance value or range can be targeted, for example, to optimize the efficiency of the system 300A, optimize heat transfer, etc. In some embodiments, the target LP-IN travel distance may be approximately 100%, 90%-110%, 80%-120%, 70%-130%, or any included or other range.

[0094] The controller 392 may further receive additional sensor data. The additional sensor data may be utilized in determining the opening of the auxiliary high pressure valve 368. The additional sensor data may include a gas cooler temperature (e.g., provided by the gauge 380). The additional sensor data input may include an indication of the system load. As used herein, the system load is the total fluid flow rate through the system 300A. The system load may be determined based on the operating speed of the main compressor 322, for example, by considering the swept volume per revolution of the main compressor 322 and the operating rotational speed of the main compressor 322. The control signal provided by the controller 392 to the auxiliary high pressure valve 368 may further depend on the additional sensor data provided to the controller 392.

[0095] The controller 393 is operably coupled to the low-pressure booster 314. The controller 393 can provide a control signal to the low-pressure booster 314 to adjust the operating speed of the low-pressure booster 314. The operating speed of the low-pressure booster 314 can be determined based on a target LP-IN travel distance of the PX 310. The controller 393 can receive sensor data indicative of the operating speed of the PX 310. The controller 393 can generate a control signal for the low-pressure booster 314 based on the operating speed of the PX 310.

[0096] In some embodiments, a controller (e.g., a central controller, a system controller, which may be combined with one or more controllers 390-393) receives sensor data indicative of the temperature of the refrigeration space (e.g., a low-temperature reservoir near evaporator 318) and / or the temperature of the heating space (e.g., a high-temperature reservoir near main gas cooler 329). The controller may control LP booster 314, auxiliary cooling component 302, auxiliary high-pressure valve 368, PX 310, and / or main compressor 322 based on the sensor data received from one or more sensors (e.g., one or more fluid flow sensors, temperature sensors, pressure sensors, etc.) of fluid treatment system 300A. In some embodiments, one or more sensors (e.g., pressure sensors, flow sensors, temperature sensors, etc.) are located near the inlets and / or outlets (e.g., fluids exiting various components) of fluid treatment system 300A. In some embodiments, one or more sensors are located internal to the components of fluid treatment system 300A. In some embodiments, a pressure sensor may be located near the inlet of the main compressor 322 and an additional pressure sensor may be located near the outlet of the main compressor 322. In some embodiments, a temperature sensor may be located near the inlet of the evaporator 318 and another temperature sensor may be located near the outlet of the evaporator 318 (e.g., to measure the temperature of the fluid exiting the evaporator 318). In some embodiments, temperature sensors may be located inside the main gas cooler 329 and / or the auxiliary gas cooler 327. In some embodiments, flow sensors may be located at the inlet and outlet of the PX 310 to measure the flow rates of the first and second fluids into and out of the PX 310, respectively.

[0097] In some embodiments, the evaporator 318 is a heat exchanger for providing corresponding thermal energy from the environment (e.g., a medium in the environment) to the fluid in the fluid treatment system 300A. For example, the evaporator 318 can receive heat (e.g., thermal energy) from the air in the environment and provide the heat to the fluid. In some embodiments, the environment is a refrigerated space, such as the inside of a refrigeration unit or freezer, an interior space (e.g., of a building or vehicle), or any other space that should be maintained at a low temperature. For example, the environment can be the interior of a freezer or refrigeration section in a supermarket or warehouse. In some embodiments, the evaporator 318 can absorb heat from the environment and provide it to the main gas cooler 329; for example, heating the area surrounding the main gas cooler 329 can be a goal of the fluid treatment system 300A.

[0098] In some embodiments, the fluid treatment system 300A may include a secondary evaporator. The fluid treatment system 300A may further include secondary components corresponding to any components of the evaporator 318, such as input and output lines, valves, gauges, controllers, etc. In some embodiments, the secondary evaporator receives a portion of the fluid flow directed to the evaporator 318. For example, the secondary evaporator may receive a portion of the flow from a low-pressure outlet of the PX 310. In some embodiments, the secondary evaporator may target a different temperature than the evaporator 318 (e.g., the evaporators may be associated with refrigeration systems having different target temperatures, such as a refrigerator and a freezer). In some embodiments, the two evaporators (e.g., the evaporator 318 and the secondary evaporator) may be operated at different fluid pressures. The fluid output by one or more of the secondary evaporators may be directed to one or more components (e.g., valves, expansion valves, pumps, compressors, etc.) to modify the pressure of the output fluid so that the pressures are substantially similar when the output flows of the two evaporators are combined.

[0099] In some embodiments, the main gas cooler 329 and / or the auxiliary gas cooler 329 are heat exchangers that provide thermal energy from the fluid in the fluid treatment system 300A to another environment. For example, the main gas cooler 329 may reject heat (e.g., thermal energy) to air in the outside (e.g., exterior) environment. In some embodiments, the main gas cooler 329 exchanges thermal energy (e.g., rejects heat) to an exterior space. For example, the main gas cooler 329 may be located on the exterior of a supermarket or warehouse building (e.g., on the roof of the building) and reject heat to the exterior environment. In other examples, the main gas cooler 329 may be located underground to facilitate the transfer of thermal energy between the fluid and the ground. In some embodiments, the main gas cooler 329 rejects heat to an interior space while the evaporator 318 absorbs heat from the exterior space (e.g., as in a heat pump configuration that provides heating to an interior space). The thermal energy rejected from the main gas cooler 329 can be used to heat an enclosed (eg, substantially enclosed) space.

[0100] In some embodiments, fluid treatment system 300A may include an auxiliary gas cooler 327. In some embodiments, the auxiliary condenser receives the second fluid from the high-pressure outlet of PX 310, and main gas cooler 329 receives the output from main compressor 322. In some embodiments, auxiliary gas cooler 327 is a heat exchanger that exchanges thermal energy (e.g., heat) between the second fluid and an environmental medium. In some embodiments, auxiliary gas cooler 327 exchanges thermal energy between the second fluid and the same environment with which main gas cooler 329 exchanges thermal energy. In other embodiments, auxiliary condenser exchanges thermal energy between the second fluid and a different environment with which main gas cooler 329 exchanges thermal energy. In some embodiments, auxiliary gas cooler 327 operates at a different temperature than main gas cooler 329.

[0101] The fluid processing system 300A further includes a high-pressure valve 304. The high-pressure valve 304 may be a controllable valve. The high-pressure valve 304 may be utilized in determining the portion of the output of the main gas cooler 329 that is supplied to the PX 310. The high-pressure valve 304 may be utilized in determining the portion of the output of the main gas cooler 329 that is supplied to the flash tank 313. The high-pressure valve 304 may be set to maintain a target high pressure within the travel distance of the PX 310. Controlling the high-pressure valve 304 may include determining the pressure of the working fluid and providing a control signal to the high-pressure valve 304 based on the pressure. The pressure of the fluid supplied to the high-pressure valve 304 (e.g., as measured by a gauge 380) may be used in determining the control signal to provide to the high-pressure valve 304. An indication of the operation of the PX 310 may further be utilized in determining a target opening for the high-pressure valve 304, in determining the control signal to provide to the high-pressure valve 304, etc. For example, the operating speed of PX 310 may be received by the controller and utilized in generating a control signal to cause actuation of high-pressure valve 304. In other examples, whether PX 310 is operated (e.g., based on ambient conditions near main gas cooler 329) may be used in determining one or more operating parameters (e.g., percentage opening) of high-pressure valve 304.

[0102] Fluid treatment system 300A further includes a flash gas valve 320. Fluid treatment system 300A can include flash gas valve 320 to regulate the flow of gas on a flash gas bypass path. In some embodiments, flash gas valve 320 is a bypass valve that regulates the flow of gas from a gas outlet of flash tank 313 so that it can be combined with the output of evaporator 318. In some embodiments, the flow of gas from flash tank 313 flows along a flash gas bypass path and bypasses evaporator 318. In some embodiments, the flash gas path is between flash tank 313 and a location downstream of the outlet of evaporator 318. The gas flowing along the flash gas bypass path can be combined with the output of evaporator 318. Flash gas valve 320 can expand (e.g., reduce the pressure of) the gas collected in flash tank 313 as the gas flows toward main compressor 322. In some embodiments, flash gas valve 320 can be an adjustable valve. In some embodiments, the flush gas valve 320 is actuated by a controller based on sensor data.

[0103] Fluid treatment system 300A may include expansion valve 316. In some embodiments, expansion valve 316 is disposed along a flow path between flash tank 313 and evaporator 318, e.g., coupled between flash tank 313 and evaporator 318. Expansion valve 316 may be an adjustable valve (e.g., an electronic expansion valve, a thermostatic expansion valve, a ball valve, a gate valve, a poppet valve, etc.). Expansion valve 316 may be controllable by a user (e.g., a technician, operator, engineer, etc.) or by a controller (e.g., a controller similar in design and / or function to one or more of controllers 390-393). In some embodiments, expansion valve 316 is actuated by a controller based on sensor data (e.g., pressure sensor data, flow sensor data, temperature sensor data, etc.). In some embodiments, expansion valve 316 is a thermal expansion valve. The expansion valve 316 may operate (e.g., open or close) based on temperature data associated with the evaporator 318 (e.g., the temperature of the liquid in the evaporator, the temperature of the gas in the evaporator, the temperature of the fluid entering the evaporator, the temperature of the fluid exiting the evaporator, etc.). For example, a pressure-sensitive component (e.g., a sensing bulb) of the expansion valve 316 may increase or decrease the pressure on a diaphragm of the expansion valve 316, causing a poppet valve coupled to the diaphragm to open or close, thus causing more or less fluid flow to the evaporator 318 and more or less expansion of the fluid. The pressure-sensitive component of the expansion valve may be located near the downstream end of the evaporator 318 (e.g., near the outlet of the evaporator 318, outside the evaporator 318, inside the evaporator 318, etc.) and may be in fluid communication with the diaphragm via a fluid line (e.g., a sensing capillary). In some embodiments, the expansion valve 316 is controlled and actuated entirely based on electronic commands (eg, from a controller).

[0104] References herein to a "first fluid" and a "second fluid" are made. In some embodiments, the first fluid and second fluid are the same type of fluid (e.g., a refrigeration fluid flowing within a fluid processing system). A "first fluid" can refer to a fluid flowing through PX310 from a high-pressure inlet to a low-pressure outlet of PX310, and / or to or from a high-pressure inlet and / or low-pressure outlet of PX310. A "second fluid" can refer to a fluid flowing through PX310 from a low-pressure inlet to a high-pressure outlet of PX310, and / or to or from a low-pressure inlet and / or high-pressure outlet of PX310.

[0105] In some embodiments, system 300A is a heat pump system capable of heating and cooling an environment (e.g., an indoor space). In some examples, one of main gas cooler 329 or evaporator 318 is an outdoor unit, and the other of main gas cooler 329 or evaporator 318 is an indoor unit. In some examples, main gas cooler 329 is an outdoor unit (e.g., a condensing unit) and evaporator 318 is an indoor unit (e.g., located within an air handling system). Fluid flow through main gas cooler 329 and evaporator 318 may be reversible (e.g., via a reversing valve coupled to main compressor 322). The reversing valve may be switchable between directing fluid flow exiting main compressor 322 to an inlet of main gas cooler 329 (e.g., an outdoor unit) or an inlet of evaporator 318 (e.g., an indoor unit). In some embodiments, one or more valves and piping may be used such that fluid flow is directed in the same direction through all components (e.g., one or more PXs 310, LP booster 314, HP booster, main compressor 322, and / or the like) while fluid flow is reversed through main gas cooler 329 and evaporator 318.

[0106] The transfer of thermal energy (e.g., heat transfer) in system 300A may be reversible in some embodiments. For example, in some implementations of system 300A, main gas cooler 329 may absorb heat (e.g., provide corresponding thermal energy from a corresponding environment to a refrigerated fluid), and evaporator 318 may reject heat (e.g., provide corresponding thermal energy from a refrigerated fluid to a corresponding environment). Thus, in some embodiments, main gas cooler 329 may be an evaporator (e.g., a single component operates as an evaporator in some modes and as a condenser in some modes), and evaporator 318 may be a condenser (e.g., a single component operates as a condenser in some modes and as an evaporator in some modes). In some embodiments, system 300A includes one or more valves (e.g., reversing valves, diverter valves, etc.) to reverse the function of system 300A (e.g., to reverse the flow of thermal energy facilitated by system 300A). In some embodiments, one or more flows of refrigeration fluid (e.g., flow to / from PX 310, to / from HP booster, to / from LP booster 314, to / from main compressor 322, to / from main gas cooler 329, and / or to / from evaporator 318) may be reversed and / or diverted. For example, in some embodiments, one or more reversing or diverting valves included in system 300A may direct fluid from main compressor 322 to evaporator 318. Similar valves may direct fluid from main gas cooler 329 to compressor 322.

[0107] The reversibility of system 300A can be controlled (e.g., via one or more controllers, via a programmable thermostat located in the indoor space, via user input). For example, the controller determines whether to use system 300A to heat or cool the indoor space (e.g., based on temperature data, based on user input, based on a schedule). In some embodiments, the controller can actuate one or more valves (e.g., reversing valves, diverter valves, etc.) to reverse the flow of fluid through main gas cooler 329 and evaporator 318. For example, the controller can actuate valves to cause refrigeration fluid to flow from main compressor 322 to evaporator 318. In such an embodiment, evaporator 318 can act as a condenser (e.g., refrigeration fluid can condense inside evaporator 318) and provide corresponding thermal energy from the refrigeration fluid to a corresponding environment (e.g., evaporator 318 can reject heat). In some examples, the controller can operate a valve to allow refrigeration fluid to flow from the main gas cooler 329 to the main compressor 322. In such embodiments, the main gas cooler 329 can act as an evaporator (e.g., the refrigeration fluid can evaporate inside the main gas cooler 329), and the main gas cooler 329 can provide corresponding thermal energy from a corresponding environment to the refrigeration fluid (e.g., the main gas cooler 329 can absorb heat). In embodiments in which the function of the system 300A is reversible (e.g., reversible between heating and cooling an indoor space), the evaporator 318 can be an internal heat exchanger (e.g., located within an air handling system that provides airflow to the indoor space, which is located within the interior space), and the main gas cooler 329 can be an external heat exchanger (e.g., located outside the interior space). Any system of the present disclosure can be a reversible system, such as a heat pump, capable of heating and cooling an interior space.

[0108] In some embodiments, the systems described herein are heat pump systems capable of heating an environment (e.g., an indoor space). In such heat pump systems, the main gas cooler 329 is located indoors and the evaporator 318 is located outdoors. In a heat pump system, the evaporator absorbs heat from the surroundings and evaporates a two-phase refrigerant fluid flowing through the evaporator before sending it to the compressor inlet. In some embodiments, to switch from a refrigeration system or an air-cooling system to a heat pump system, a reversing valve may be used to switch the fluid flow exiting the main compressor 322 between being directed to the inlet of the outdoor unit or the inlet of the indoor unit. In some embodiments, one or more valves and piping may be used to switch the fluid flow from the indoor unit to the outdoor unit while the fluid flow is directed in the same direction through all components (e.g., one or more PXs 310, LP booster 314, HP booster, main compressor 322, and / or the like).

[0109] The direction of thermal energy transfer (e.g., heat transfer) of system 300A may be reversible in some embodiments. For example, in a refrigeration / air conditioning / air-cooling implementation of system 300A, the main gas cooler 329 located outdoors may reject heat (e.g., provide corresponding thermal energy from a refrigerated fluid to a corresponding environment), and the evaporator 318 may absorb heat (e.g., provide corresponding thermal energy from a corresponding environment to the refrigerated fluid). In a heat pump implementation of system 300A, the main gas cooler 329 located indoors may reject heat to its indoor environment, and the evaporator 318 may absorb heat from its outdoor environment. In some embodiments, system 300A includes one or more valves (e.g., reversing valves, diverter valves, etc.) to reverse the function of system 300A (e.g., to reverse the flow of thermal energy facilitated by system 300A). In some embodiments, one or more flows of refrigeration fluid (e.g., flow to / from PX 310, to / from HP booster, to / from LP booster 314, to / from main compressor 322, to / from main gas cooler 329, and / or to / from evaporator 318) may be reversed and / or diverted. In some examples, one or more reversing or diverting valves included in some embodiments of system 300A can direct fluid from main gas cooler 322 to the outdoor unit. Similar valves can direct fluid from main compressor 322 to the indoor unit.

[0110] The reversibility of system 300A can be controlled (e.g., via a controller of system 300A, via a programmable thermostat located in the indoor space, via user input, etc.). In some examples, the controller can determine whether to use system 300A to heat or cool the indoor space (e.g., based on temperature data, based on user input, based on a schedule). In some embodiments, the controller can actuate one or more valves (e.g., reversing valves, diverter valves, etc.) to reverse the flow of fluid through the system. In embodiments in which the function of system 300A is reversible (e.g., reversible between heating and cooling the indoor space), evaporator 318 can be an internal heat exchanger (e.g., located within the interior space and in an air handling system that supplies airflow to the indoor space), and main gas cooler 329 can be an external heat exchanger (e.g., located outside the interior space). In other embodiments, evaporator 318 can be an outdoor heat exchanger, and main gas cooler 329 can be an indoor heat exchanger.

[0111] In some embodiments, the systems described herein (e.g., one or more of the systems of FIGS. 3A-B) can be used to heat interior and / or enclosed spaces, to cool interior and / or enclosed spaces, and / or to selectively (e.g., reversibly) heat and cool spaces.

[0112] Figure 3B is a schematic diagram of a fluid treatment system 300B including a pressure exchanger (PX310) without a low-pressure booster, according to some embodiments. In some embodiments, features having reference numbers corresponding to reference numbers in other figures include similar properties, structures, and / or functions as those described in the other figures. In some embodiments, any of the components described in connection with Figure 3A (e.g., a secondary evaporator, a compressor system instead of the main compressor 322, etc.) may also be optional components for fluid treatment system 300B. In some examples, features of fluid treatment system 300B have similar properties, structures, and / or functions as fluid treatment system 300A of Figure 3A.

[0113] Fluid treatment system 300B may be configured to provide heat transfer (e.g., refrigeration) through the circulation of a working fluid (e.g., CO2). Fluid treatment system 300B may be configured to take action to regulate one or more components of fluid treatment system 300B based on sensor data generated by sensors in fluid treatment system 300B. In some embodiments, fluid treatment system 300B may take action to achieve and / or maintain a target temperature of the bulk fluid from a heat exchanger, e.g., output from heat exchanger 315. In some embodiments, fluid treatment system 300B may receive temperature data from one or more temperature sensors indicative of the temperature of the fluid in fluid treatment system 300B. Fluid treatment system 300B may operate one or more valves (e.g., bypass high pressure valve 348) based on the temperature data. Fluid treatment system 300B may regulate one or more components to achieve and / or maintain a target fluid temperature, a target fluid subcooling, or the like.

[0114] Fluid treatment system 300B may include a bypass high pressure valve 348. Bypass high pressure valve 348 may be an expansion valve or a flow control valve. In some embodiments, bypass high pressure valve 348 selectively regulates the flow of fluid from an outlet of main gas cooler 329 (e.g., fluid discharged by main gas cooler 329) to heat exchanger 315, auxiliary gas cooler 327, and / or flash tank 313 (e.g., receiver) in parallel with PX 310. In some embodiments, bypass high pressure valve 348 may be actuated to selectively regulate the flow of fluid. Bypass high pressure valve 348 may selectively provide a portion of the fluid output by main gas cooler 329 to flash tank 313. For example, bypass high pressure valve 348 may be actuated to open further to allow more fluid to flow from main gas cooler 329 to flash tank 313, or bypass high pressure valve 348 may be actuated to close further to allow less fluid to flow from main gas cooler 329 to flash tank 313. Fluid may expand as it flows through bypass high pressure valve 348, which may cause a decrease in the pressure and / or temperature of the fluid. In some embodiments, controller 394 may actuate (e.g., open or close) bypass high pressure valve 348 based on sensor data received from one or more sensors in fluid treatment system 300B.

[0115] In some embodiments, the main gas cooler 329 may act as a condenser. In some embodiments, the fluid processing system may operate at pressures and temperatures where fluid may or may not condense in the main gas cooler 329. Any of the embodiments discussed herein may include a condenser that may act as a gas cooler in one or more applications.

[0116] Fluid treatment system 300B can include a flash tank 313 (e.g., a receiver). In some embodiments, flash tank 313 is a receiver configured to receive a flow of fluid (e.g., a first fluid) output from the low-pressure outlet of PX 310. Flash tank 313 may form a chamber for collecting the first fluid from the first outlet of PX 310. Flash tank 313 can receive the first fluid in a two-phase state (e.g., liquid and gas), a transcritical fluid, a supercritical fluid, a subcritical fluid, and / or combinations thereof. In some embodiments, flash tank 313 is a tank constructed of welded sheet metal. Flash tank 313 can include one or more flash tank inlets for receiving the fluid and one or more flash tank outlets (e.g., a gas outlet and a liquid outlet) for discharging the fluid. The first fluid (at low pressure) may separate into a gas and a liquid inside flash tank 313 (e.g., as indicated by the liquid surface shown in FIG. 3B). Liquid of the first fluid may settle to the bottom of flash tank 313, while vapor of the first fluid may rise to the top of flash tank 313. Liquid may flow from flash tank 313 toward evaporator 318 (e.g., via expansion valve 316). The chamber of flash tank 313 may be maintained at a set pressure. The pressure may be set by a user (e.g., an operator, technician, engineer, etc.) and / or by a controller. In some embodiments, the pressure of flash tank 313 is controlled by one or more valves (e.g., expansion valve 316, flash gas valve 320, pressure regulator valve, safety valve, etc.). In some embodiments, flash tank 313 includes at least one pressure sensor (e.g., a pressure transducer). In some embodiments, the liquid level in flash tank 313 may be monitored (e.g., to prevent liquid from being directed through flash gas valve 320).

[0117] Fluid treatment system 300B may include expansion valve 316. In some embodiments, expansion valve 316 is disposed along the flow path between flash tank 313 and evaporator 318, such as coupled between flash tank 313 and evaporator 318. Expansion valve 316 may be an adjustable valve (e.g., an electronic expansion valve, a thermostatic expansion valve, a ball valve, a gate valve, a poppet valve, etc.). Expansion valve 316 may be controllable by a user (e.g., a technician, operator, engineer, etc.) or by a controller (e.g., a controller sharing one or more features with controller 394). In some embodiments, expansion valve 316 is actuated by a controller based on sensor data (e.g., pressure sensor data, flow sensor data, temperature sensor data, etc.). In some embodiments, expansion valve 316 is a thermal expansion valve. The expansion valve 316 may operate (e.g., open or close) based on temperature data associated with the evaporator 318 (e.g., the temperature of the liquid in the evaporator, the temperature of the gas in the evaporator, the temperature of the fluid entering the evaporator, the temperature of the fluid exiting the evaporator, etc.). For example, a pressure-sensitive component (e.g., a sensing bulb) of the expansion valve 316 can increase or decrease the pressure on a diaphragm of the expansion valve 316, causing a poppet valve coupled to the diaphragm to open or close, thus causing more or less fluid flow to the evaporator 318 and more or less expansion of the fluid. The pressure-sensitive component of the expansion valve may be located near the downstream end of the evaporator 318 (e.g., near the outlet of the evaporator 318, outside the evaporator 318, inside the evaporator 318, etc.) and may be fluidly connected to the diaphragm via a fluid line (e.g., a sensing capillary). In some embodiments, the expansion valve 316 is controlled and operated entirely based on electronic commands.

[0118] Fluid treatment system 300B may include a flash gas valve 320 to regulate the flow of gas on a flash gas bypass flow path. In some embodiments, flash gas valve 320 is a bypass valve that regulates the flow of gas from a gas outlet of flash tank 313 to be combined with the output of evaporator 318. In some embodiments, the flow of gas from flash tank 313 flows along the flash gas bypass flow path and bypasses evaporator 318. In some embodiments, the flash gas flow path is between flash tank 313 and a location downstream of the outlet of evaporator 318. Gas flowing along the flash gas bypass flow path may be combined with the output of evaporator 318. Flash gas valve 320 may expand (e.g., reduce pressure) gas collected in flash tank 313 as the gas flows toward main compressor 322. In some embodiments, flash gas valve 320 may be an adjustable valve. In some embodiments, flash gas valve 320 is operated by a controller based on sensor data.

[0119] In some embodiments, fluid treatment system 300B may further include one or more additional heat exchangers, such as heat exchanger 315, for exchanging heat between fluids in different portions of fluid treatment system 300B. For example, fluid treatment system 300B may include a heat exchanger for exchanging heat between fluid output by main gas cooler 329 and fluid output by flash tank 313. Heat exchanger 315 may be used to exchange heat between fluid output by main gas cooler 329 and fluid expanded through bypass high-pressure valve 348. A first flow path including one or more fluid channels through the heat exchanger may be coupled between an outlet of main gas cooler 329 and both the high-pressure inlet of PX 310 and bypass high-pressure valve 348. A second flow path including one or more fluid channels through the heat exchanger may be coupled between an outlet of bypass high-pressure valve 348 and the low-pressure inlet of PX 310. The heat exchangers may be configured to exchange heat between fluid traveling along the first flow path and fluid traveling along the second flow path. Fluid being cooled (e.g., fluid along the main fluid path, fluid directly connected to the main gas cooler 329 and / or main compressor 322, etc.) may pass through the bulk fluid channels of the heat exchanger 315 via a bulk fluid inlet and a bulk fluid outlet. The heat exchanger may transfer heat from the main gas cooler 329 output fluid to the bypass high-pressure valve 348 output fluid. The fluid may expand through the bypass high-pressure valve 348 and decrease in temperature and / or pressure. The cooler expanded fluid may be utilized as a heat sink for the bulk fluid in the heat exchanger 315.

[0120] The heat exchanger 315 may be configured to achieve cooling of the bulk fluid passing through the bulk fluid channel of the heat exchanger 315. The heat exchanger 315 may be configured to achieve a target subcooling of the bulk fluid passing through the heat exchanger 315. Subcooling refers to cooling the fluid below the temperature at which the fluid condenses into a liquid, for fluids having a liquid / gas transition. The subcooling can be measured by measuring the temperature of the fluid, for example, with a temperature gauge 386. The heat exchanger 315 can target a temperature drop across the heat exchanger 315, which can be measured, for example, with a temperature gauge 386 after the bulk fluid flows through the heat exchanger 315 and a temperature gauge 388 before the bulk fluid flows through the heat exchanger 315.

[0121] Controller 394 can provide a control signal for operating bypass high-pressure valve 348. Controller 394 can receive temperature data from one or more temperature sensors, for example, from temperature gauge 386 and / or temperature gauge 388. Controller 394 can generate a control signal for bypass high-pressure valve 348 based on the sensor data. Controller 394 can generate a control signal to cause actuation of bypass high-pressure valve 348 to a target opening. Controller 394 can generate a control signal to target the temperature of the bulk fluid output by heat exchanger 315, a target level of subcooling of the bulk fluid in heat exchanger 315, etc.

[0122] In another example, fluid treatment system 300B can include a heat exchanger including a first flow path coupled between the output of flash tank 313 and the output stream of evaporator 318, and a second flow path coupled prior to the low-pressure inlet of PX 310. The heat exchanger can facilitate the transfer of heat from near the inlet of PX 310 to the fluid output from flash tank 313. Similar to the heat exchanger in the previous example, the transfer of heat through the heat exchanger can improve operation, for example, by evaporating liquid and / or increasing the superheat of the output stream of evaporator 318, increasing the density of the fluid flowing through PX 310, thereby increasing the COP, etc.

[0123] In another example, fluid treatment system 300B can include a heat exchanger including a first flow path coupled between an outlet of flash tank 313 and the output stream of evaporator 318, and a second flow path coupled between a high-pressure outlet of PX 310 and an inlet of flash tank 313. Heat can be provided to the output of flash tank 313. The benefits provided can be similar to those of the heat exchangers described above.

[0124] In some embodiments, fluid processing system 300B can include an auxiliary high-pressure valve 369. Auxiliary high-pressure valve 369 can control flow through auxiliary gas cooler 327. Auxiliary high-pressure valve 369 can be coupled to bypass high-pressure valve 348, for example, two high-pressure valves can be along the same fluid flow path. Auxiliary high-pressure valve 369 can have an effect on the travel distance of PX 310, for example, the low-pressure inlet travel distance. Controller 395 can provide a control signal to auxiliary high-pressure valve 369.

[0125] Controller 395 can receive an input indicative of the opening degree of bypass high pressure valve 348. Auxiliary high pressure valve 369 can be provided with a control signal based on the opening degree of bypass high pressure valve 348 such that the flow through auxiliary high pressure valve 369 corresponds to the flow through bypass high pressure valve 348. Various characteristics of fluid treatment system 300B, for example, characteristics of components disposed between bypass high pressure valve 348 and auxiliary high pressure valve 369, can be further utilized in determining the target opening degree of auxiliary high pressure valve 369. The signal indicative of the opening degree of bypass high pressure valve 348 provided to controller 395 can be provided by bypass high pressure valve 348, a sensor associated with bypass high pressure valve 348, controller 394 providing the control signal for bypass high pressure valve 348, etc. Controller 395 can determine the target opening degree of bypass high pressure valve 348 based on signals from temperature gauge 386 and / or temperature gauge 388, and determine the opening degree of auxiliary high pressure valve 369 based on the determined opening degree of bypass high pressure valve 348. Controller 395 may receive temperature data from one or more of temperature gauge 386 or temperature gauge 388 and determine the opening of auxiliary high pressure valve 369 based on the temperature data. Controller 395 may also receive data indicative of the total system load of fluid treatment system 300B. The total system load may be determined based on the specifications (e.g., swept volume) and operating speed of main compressor 322.

[0126] In some embodiments, the fluid treatment system 300B may include a PX high-pressure valve and / or a PX on / off valve. The PX high-pressure valve may control the flow of fluid output from the high-pressure outlet of the PX. The PX high-pressure valve may be coupled between the high-pressure outlet of the PX and the inlet of the flash tank 313. Expanding the fluid entering the flash tank 313 through the PX high-pressure valve may change the gas-to-liquid ratio of the fluid in the flash tank 313. The PX on / off valve may control the flow of high-pressure fluid from the outlet of the main gas cooler 329 to the high-pressure inlet of the PX 310. The PX high-pressure valve and / or the PX on / off valve may be controlled by one or more controllers. The valves may be controlled based on measurements received from one or more sensors. For example, the PX high-pressure valve may be adjusted based on a sensor reporting the gas-to-liquid ratio in the flash tank 313.

[0127] In some embodiments, one or more components of fluid treatment system 300B and / or fluid treatment system 300A may be provided as a retrofit, as an addition to an existing fluid treatment system, as an upgrade package, etc. For example, a refrigeration system may not include PX 310, LP booster 314, one or more high-pressure valves, etc. All fluid input to main gas cooler 329 in a refrigeration system may pass through main compressor 322. Components including PX 310, associated motors, controllers 390-395, high-pressure valves, etc. may be added to the system, for example, to increase the energy efficiency of the system through the introduction of PX 310 (e.g., for energy recovery, for pressure transfer, etc.).

[0128] In some embodiments, a PX system (e.g., fluid treatment system 300A, fluid treatment system 300B, etc.) may be included in the system with additional components. The additional components (e.g., a parent rack) may include sufficient components to operate the fluid treatment system without the various components included in FIGS. 3A-B , such as PX 310, auxiliary gas cooler 327, LP booster 314, auxiliary high-pressure valves 368 and 369, bypass high-pressure valve 348, etc. In some embodiments, operation of the fluid treatment system may be performed such that PX 310 and associated components are bypassed, e.g., by selecting components of the parent rack. One or more sensors may determine whether operation of PX 310 and associated components should occur. For example, under certain combinations of target conditions, ambient conditions, fluid conditions, etc., PX 310 may not provide sufficient value to justify operation of PX 310 and associated components. Under such conditions, PX310 may be bypassed and the parent rack may be utilized for operations performed by PX310 and the other components described in connection with Figures 3A-B.

[0129] In some embodiments, the temperature of the fluid between the main gas cooler 329 and the HP-IN of the PX 310 can be used to determine whether to operate the PX 310. A shunt to a parent rack to bypass the PX 310, along with one or more associated valves, can be placed in the fluid path between the main gas cooler 329 and the HP-IN of the PX 310. The valve directing the fluid flow to the PX 310 can be operated based on the temperature of the fluid provided to the HP-IN of the PX 310. In some embodiments, one or more valves can be included for safety; for example, if a sensor detects a condition that could damage one or more components of the fluid processing system, a safety valve can close to prevent or reduce damage to one or more components of the system.

[0130] 4A-C are flow diagrams illustrating methods 400A-C for controlling a fluid processing system (e.g., one or more of fluid processing systems 300A-B of FIGS. 3A-B) according to some embodiments. In some embodiments, methods 400A-C are performed by processing logic including hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, a processing device, etc.), software (e.g., instructions executed on a processing device, a general-purpose computer system, or a dedicated machine), firmware, microcode, or a combination thereof. In some embodiments, methods 400A-C are performed, at least in part, by one or more controllers (e.g., control module 180 of FIGS. 1A-B, controllers 390-395 of FIGS. 3A-B). In some embodiments, a non-transitory storage medium stores instructions that, when executed by one or more processing devices (e.g., those of control module 180 of FIGS. 1A-B, controllers 390-395 of FIGS. 3A-B), cause the processing devices to perform methods 400A-C.

[0131] For ease of explanation, methods 400A-C are shown and described as a series of operations. However, operations according to the present disclosure may occur in various orders and / or simultaneously, and with other operations not shown and described herein. Moreover, in some embodiments, not all illustrated operations are performed to implement methods 400A-C in accordance with the disclosed subject matter. In addition, those skilled in the art will understand and appreciate that methods 400A-C may alternatively be represented as a series of interrelated states via a state diagram or events.

[0132] 4A is a flow diagram of a method 400A for providing control of one or more components of a fluid treatment system, according to some embodiments. The fluid treatment system of method 400A may be a heat transfer system, a heat pump system, a refrigeration system, and / or the like (e.g., one or more of the architectures described in connection with one or more of FIGS. 3A-3B).

[0133] At block 402, processing logic optionally identifies first pressure data associated with a condenser of the heat transfer system. Processing logic may determine an operating speed of a PX of the heat transfer system (e.g., PX 310 of FIG. 3A) based on the first pressure data. The condenser may, in some embodiments, be a gas cooler, such as main gas cooler 329 of FIG. 3A.

[0134] At block 404, processing logic identifies a first indication of an operating speed of a pressure exchanger (PX) of the heat transfer system. Identifying the first indication of operating speed may include receiving sensor data from a sensor measuring the operating speed of the PX (e.g., the rotational speed of the rotor). Identifying the first indication of operating speed may include receiving a control signal directed to adjust the operating speed of the PX. Identifying the first indication of speed may include receiving sensor data, on which the control signal is based, regarding the operating speed of the PX.

[0135] At block 406, processing logic optionally identifies a second indication of the temperature of the fluid entering the high-pressure inlet of the PX. At block 408, processing logic optionally identifies a third indication of system load, optionally based on the operating speed of one or more compressors of the heat transfer system. One or more compressors may be main compressors, e.g., the one or more compressors may drive fluid between an evaporator (e.g., a heat source) and a condenser (e.g., a heat sink) of the heat transfer system. System load, as used herein, refers to the total amount of fluid (e.g., refrigeration fluid) transferred through the system (e.g., mass flow rate through a main compressor or set of main compressors). System load may further be based on system and / or main compressor specifications, such as fluid pressure, fluid pressure at the main compressors, operating volume of the main compressors (e.g., swept volume of fluid displaced during one stroke or one revolution), etc.

[0136] At block 410, processing logic determines a target opening value for a first valve based on a first indication of the operating speed of the PX. The inlet of the first valve is coupled to a high-pressure outlet of the PX. The inlet of the first valve may be configured to receive fluid output by the high-pressure outlet of the PX, for example, the first valve may be in direct fluid communication with the high-pressure outlet of the PX. Determining the target opening value for the first valve may be further based on additional data, such as a second indication of the temperature of the high-pressure inlet of the PX and / or a third indication of system load.

[0137] At block 412, processing logic causes actuation of the first valve based on the target opening value. Actuation of the first valve may adjust the opening of the first valve to the target value.

[0138] At block 414, processing logic optionally determines a target operating speed of the low-pressure booster based on the first indication. The low-pressure booster (e.g., an outlet of the low-pressure booster) may be coupled to the low-pressure inlet of the PX. The target operating speed of the low-pressure booster may be further based on a relationship between the operating speed of the low-pressure booster and the operating speed of the PX. The relationship may be enumerated, for example, coded, or recorded in a look-up table. The relationship may be functional, formulaic, or the like. Determining the target operating speed of the low-pressure booster may be further based on a measured pressure difference between a first pressure of the fluid at the low-pressure inlet of the PX and a second pressure of the fluid at the low-pressure outlet of the PX. Processing logic may receive pressure difference data for determining the target operating speed of the low-pressure booster.

[0139] At block 416, processing logic optionally causes an adjustment of the operating speed of the low-pressure booster based on a target operating speed of the low-pressure booster. The adjustment of the operating speed of the low-pressure booster (and the operation of the adjustments or components described in Figures 4A-4C) may be performed by the processing logic of the controller by providing a control signal to the low-pressure booster to cause the adjustment of the operating speed of the low-pressure booster.

[0140] 4B is a flow diagram of a method 400B for regulating operation of a fluid treatment system including a low-pressure booster (e.g., via controller 393 of FIG. 3A) according to some embodiments. At block 420, processing logic optionally identifies first pressure data associated with a condenser of the heat transfer system. At block 422, processing logic optionally determines an operating speed of PX based on the first pressure data. The operations of blocks 420 and 422 may share characteristics with the operations of block 402 of FIG. 4A.

[0141] At block 424, processing logic obtains a first indication of the operating speed of the PX of the heat transfer system. The operations of block 424 may share characteristics with the operations of block 404.

[0142] In block 426, the processing logic determines a target operating speed of the low-pressure booster. The outlet of the low-pressure booster is fluidly connected to supply fluid to the low-pressure inlet of the PX. The target operating speed of the low-pressure booster is based on the operating speed of the PX. The target operating speed of the low-pressure booster may be further based on a relationship between the operating speed of the low-pressure booster and the operating speed of the PX. The relationship may be a functional relationship stored in a look-up table or the like. The target operating speed of the low-pressure booster may be further based on a target low-pressure inlet travel distance of the PX. The target operating speed of the low-pressure booster may be further based on specifications of the low-pressure booster and / or the PX, such as the operating volumes of the booster and the PX, the pumping efficiency of the booster and the PX, the swept volume of the booster, the duct volume of the PX, etc.

[0143] At block 428, processing logic causes an adjustment of the operating speed of the low-pressure booster. The adjustment may be based on a target operating speed of the low-pressure booster. The adjustment may cause the low-pressure booster to operate at the target speed. This adjustment may be made by providing a control signal to the low-pressure booster (e.g., a motor of the low-pressure booster) that is indicative of the target operating speed.

[0144] At block 430, processing logic optionally identifies an indication of the temperature of an auxiliary gas cooler of the heat transfer system. The inlet of the auxiliary gas cooler can be configured to receive fluid from the high-pressure outlet of the PX (e.g., the auxiliary gas cooler can be coupled in the fluid flow path of the fluid treatment system immediately after the high-pressure outlet of the PX). At block 432, processing logic optionally adjusts operation of a cooling component of the auxiliary gas cooler based on the second indication. The cooling component may be a fan, a coolant pump, or other component configured to increase heat transfer from the fluid of the fluid treatment system to the ambient environment at the auxiliary gas cooler.

[0145] FIG. 4C is a flow diagram of a method 400C for adjusting the operation of a boosterless PX system based on sensor data of the PX system (e.g., via the controller 394 of FIG. 3B), according to some embodiments. In block 440, processing logic identifies first temperature data indicative of a temperature difference between a fluid at a bulk inlet of the heat exchanger and a fluid at a bulk outlet of the heat exchanger. The bulk outlet of the heat exchanger is coupled to the bulk inlet of the heat exchanger via one or more channels of the heat exchanger, e.g., via channels passing through the heat exchanger to facilitate the exchange of thermal energy between the bulk fluid and the secondary fluid. The bulk outlet of the heat exchanger may be fluidly connected to a high-pressure inlet of the PX. The bulk outlet of the heat exchanger may be directly coupled to the high-pressure inlet of the PX, e.g., the high-pressure inlet of the PX may be configured to receive fluid from the bulk outlet of the heat exchanger.

[0146] At block 442, the processing logic determines a target adjustment of the first valve. The determination may be made based on the first temperature data. The first valve may be fluidly connected to a bulk outlet of the heat exchanger and a cooling fluid inlet (e.g., a secondary inlet) of the heat exchanger. The first valve may be fluidly connected between the bulk outlet of the heat exchanger and the cooling fluid inlet of the heat exchanger. The cooling fluid inlet may be configured to receive the output of the bulk outlet of the heat exchanger via the first valve. Determining the target adjustment of the first valve may include determining that a subcooling value of the bulk fluid in the heat exchanger does not meet a threshold value. Determining the target adjustment of the first value may include determining that the target adjustment is predicted to adjust the subcooling value of the bulk fluid to be within a threshold target level of subcooling. The adjustment may be based on a relationship between fluid flow (e.g., mass flow rate) to the cooling inlet (e.g., the amount of cooling fluid provided to a secondary channel of the heat exchanger) and the subcooling of the bulk fluid.

[0147] At block 444, processing logic causes actuation of the first valve based on the target adjustment of the first valve. The actuation may be toward the target position of the first valve.

[0148] In block 446, the processing logic optionally determines a target adjustment for the second valve based on the opening degree of the first valve. The second valve may be fluidly connected to the high-pressure outlet of the PX. The second valve may be fluidly connected between the high-pressure outlet of the PX and an inlet to the flash tank. The second valve may be fluidly connected to an outlet of a gas cooler, for example, an outlet of an auxiliary gas cooler. The second valve and the gas cooler may be disposed in a fluid path between the high-pressure outlet of the PX and an inlet (e.g., a receiver) of the flash tank. The target adjustment for the second valve may further be based on the mass flow rate through the first valve and the second valve, for example, a look-up table including a correspondence between the opening degrees of the first valve and the second valve and including the mass flow rate through the first valve and the second valve. The target adjustment for the second valve may further be based on a total system load of the heat transfer system including the PX (e.g., total fluid flow rate through the main compressor, total fluid flow rate through the evaporator or condenser, etc.). The target adjustment of the second valve may be further based on temperature data indicative of the temperature of the fluid at the bulk outlet of the heat exchanger.

[0149] At block 448, processing logic optionally causes actuation of the second valve based on a target opening for the second valve.

[0150] 5 is a block diagram illustrating a computer system 500 according to some embodiments. In some embodiments, the computer system 500 is a client device. In some embodiments, the computer system 500 is a controller device (e.g., a server, control module 180 of FIGS. 1A-B, controllers 390-395 of FIGS. 3A-B, etc.).

[0151] In some embodiments, computer system 500 is connected to other computer systems (e.g., via a network such as a local area network (LAN), an intranet, an extranet, or the Internet). Computer system 500 operates in the capacity of a server or a client computer in a client-server environment, or as a peer computer in a peer-to-peer or distributed network environment. In some embodiments, computer system 500 is provided by a personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a cellular phone, a web appliance, a server, a network router, switch, or bridge, or any device capable of executing a set of instructions (sequential or otherwise) that specify operations to be performed by that device. Furthermore, the term "computer" is intended to include any collection of computers that individually or jointly execute a set or sets of instructions to perform any one or more of the methods described herein.

[0152] In some embodiments, computer system 500 includes a processing device 502, volatile memory 504 (e.g., random access memory (RAM)), non-volatile memory 506 (e.g., read-only memory (ROM) or electrically erasable programmable ROM (EEPROM)), and / or data storage device(s) 516 that communicate with each other via a bus 508.

[0153] In some embodiments, processing device 502 is provided by a general-purpose processor (e.g., a Complex Instruction Set Computing (CISC) microprocessor, a Reduced Instruction Set Computing (RISC) microprocessor, a Very Long Instruction Word (VLIW) microprocessor, a microprocessor implementing other types of instruction sets, or a combination of instruction set types, etc.) or a special-purpose processor (e.g., an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a Digital Signal Processor (DSP), a PID controller, or a network processor, etc.). In some embodiments, processing device 502 is provided by one or more of a single processor, multiple processors, a single processor with multiple processing cores, and / or the like.

[0154] In some embodiments, computer system 500 further includes a network interface device 522 (e.g., coupled to network 574). In some embodiments, computer system 500 includes one or more input / output (I / O) devices. In some embodiments, computer system 500 also includes a video display unit 510 (e.g., a liquid crystal display (LCD)), an alphanumeric input device 512 (e.g., a keyboard), a cursor control device 514 (e.g., a mouse), and / or a signal generating device 520. Computer system 500 may include a signal input device 515, e.g., for receiving signals from other devices. For example, signal input device 515 may facilitate receipt by computer system 500 of measurement data from sensors associated with the fluid process system. Signal generating device 520 may be utilized to generate and / or transmit control signals for sending commands to one or more components of the fluid process system. Signal generating device 520 may send control signals to various high-pressure valves, booster pumps, cooling components, PX components, etc.

[0155] In some embodiments, data storage device 518 (e.g., disk drive storage, fixed and / or removable storage, fixed disk drive, removable memory card, optical storage, network attached storage, and / or storage area network (SAN)) includes a non-transitory computer-readable storage medium 524 that stores instructions 526 encoding one or more of the methods or functions described herein to perform the methods described herein. A control module 527 (e.g., including any of controllers 390-395 of FIGS. 3A-B) may include instructions 526.

[0156] In some embodiments, the instructions 526 also reside, completely or partially, within the volatile memory 504 and / or within the processing device 502 during execution thereof by the computer system 500; thus, in some embodiments, the volatile memory 504 and the processing device 502 also constitute machine-readable storage media.

[0157] Although the computer-readable storage medium 524 is shown as a single medium in the illustrative example, the term "computer-readable storage medium" is intended to include a single medium or multiple media (e.g., centralized or distributed databases and / or associated caches and servers) that store one or more sets of executable instructions. The term "computer-readable storage medium" is also intended to include any tangible medium that is capable of storing or encoding a set of instructions for execution by a computer that cause the computer to perform any one or more of the methods described herein. The term "computer-readable storage medium" is intended to include, but is not limited to, solid-state memory, optical media, and magnetic media.

[0158] The methods, components, and features described herein may be implemented by discrete hardware components or may be integrated into the functionality of other hardware components, such as an ASIC, FPGA, DSP, or similar device. Further, the methods, components, and features may be implemented by firmware modules or functional circuits within a hardware device. Furthermore, the methods, components, and features may be implemented in any combination of hardware devices and computer program components, or in a computer program.

[0159] Unless otherwise specified or clear from the context, terms such as "operate," "regulate," "cause," "control," "determine," "identify," "provide," "receive," "generate," "obtain," and the like refer to actions and processes performed or implemented by a computer system that manipulate and transform data represented as physical (electronic) quantities in computer system registers and memory into other data similarly represented as physical quantities in computer system memory or registers, or other such information storage, transmission, or display devices. Also, as used herein, terms such as "first," "second," "third," "fourth," and the like are meant as labels to distinguish different elements and may not have an ordinal meaning consistent with their numerical designations.

[0160] The examples described herein also relate to apparatus for performing the methods described herein. This apparatus may be specially constructed to perform the methods described herein, or may comprise a general-purpose computer system that is selectively programmed by a computer program stored on the computer system. Such a computer program may be stored on a computer-readable tangible storage medium.

[0161] The methods and illustrative examples described herein are not inherently related to any particular computer or other apparatus. Various general-purpose systems may be used in accordance with the teachings described herein, or it may prove convenient to construct more specialized apparatus to perform the methods described herein and / or each of their individual functions, routines, subroutines, or operations. Examples of constructions for a variety of these systems are set forth in the description above.

[0162] The foregoing description sets forth numerous specific details, such as examples of particular systems, components, methods, etc., to provide a thorough understanding of some embodiments of the present disclosure. However, it will be apparent to those skilled in the art that at least some embodiments of the present disclosure may be practiced without these specific details. In other instances, well-known components or methods are not described in detail or are presented in simple block diagram form to avoid unnecessarily obscuring the present disclosure. Thus, the specific details described are merely exemplary. Particular implementations may differ from these example details and still be contemplated within the scope of the present disclosure. The system descriptions herein may include descriptions of one or more of any components. Components may be included in combinations not specifically discussed in the present disclosure and still be within the scope of the present disclosure. For example, any of the controllers 390-395 of FIGS. 3A-D, alone or in any combination, may be included in a fluid processing system within the scope of the present disclosure.

[0163] References throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrase "in one embodiment" or "in an embodiment" in various places throughout this specification do not necessarily all refer to the same embodiment. In addition, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or." When terms such as "about," "substantially," or "approximately" are used herein, this is intended to mean that the stated nominal value is accurate to within ±10%. Also, as used herein, terms such as "first," "second," "third," and "fourth" are intended as labels to distinguish between different elements and do not necessarily have an ordinal meaning according to their numerical designations.

[0164] As used herein, the terms "above," "below," "between," "disposed on," "before," "after," and "on" refer to the relative location of one layer or component of a material with respect to another layer or component. For example, a layer disposed on, above, or below another layer may be in direct contact with the other layer or may have one or more intervening layers. Furthermore, a layer disposed between two layers may be in direct contact with the two layers or may have one or more intervening layers. Similarly, unless otherwise specified, a feature disposed between two features may be in direct contact with the adjacent feature or may have one or more intervening layers or components.

[0165] Although the operations of the methods herein are shown and described in a particular order, the order of the operations of each method may be changed such that certain operations may be performed in the reverse order, or such that certain operations may be performed at least in part concurrently with other operations. In other embodiments, instructions for separate operations or sub-operations may exist in an intermittent and / or alternating manner.

[0166] It should be understood that the above description is illustrative and not restrictive. Many other embodiments will become apparent to those skilled in the art upon reading and understanding the above description. The scope of the present disclosure should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which each claim is entitled.

Claims

1. 1. A method, comprising: identifying, by a processing device, a first indication of an operating speed of a pressure exchanger (PX) of the heat transfer system; determining a target opening value for a first valve based on the first indication of an operating speed of the PX, the first valve having an inlet coupled to a high pressure outlet of the PX, the method further comprising: causing actuation of the first valve based on the target opening value.

2. 2. The method of claim 1, wherein the method further includes identifying a second indication of the temperature of the fluid communicated to the high pressure inlet of the PX, and wherein triggering actuation of the first valve is further based on the second indication.

3. The method of claim 1 , wherein the method further comprises identifying a third indication of system load, and wherein determining the target opening value of the first valve is further based on the system load.

4. The method of claim 3 , wherein the system load is determined based on the operating speed of one or more compressors of the heat transfer system.

5. The method comprises: determining a target operating speed of a low pressure booster based on the first indication of an operating speed of the PX, the outlet of the low pressure booster being coupled to a low pressure inlet of the PX, the method further comprising: The method of claim 1 , comprising causing an adjustment of the operating speed of the low pressure booster based on the target operating speed of the low pressure booster.

6. The method of claim 5 , wherein determining the target operating speed of the low-pressure booster is based on a relationship between an operating speed of the low-pressure booster and an operating speed of a PX.

7. 6. The method of claim 5, further comprising determining a pressure difference between a first pressure of the fluid at a low pressure inlet of the PX and a second pressure of the fluid at a low pressure outlet of the PX, and determining the target operating speed of the low pressure booster is further based on the pressure difference.

8. The method comprises: identifying first pressure data associated with a condenser of the heat transfer system; The method of claim 1 , further comprising: determining an operating speed of the PX based on the first pressure data.

9. 1. A method, comprising: obtaining, by a processing device, a first indication of an operating speed of a pressure exchanger (PX) of the heat transfer system; determining a target operating speed of a low pressure booster based on the first indication of an operating speed of the PX, the outlet of the low pressure booster being coupled to supply fluid to a low pressure inlet of the PX, the method further comprising: causing an adjustment of an operating speed of the low pressure booster based on the target operating speed of the low pressure booster.

10. The method of claim 9 , wherein determining the target operating speed of the low-pressure booster is based on a relationship between an operating speed of the low-pressure booster and an operating speed of a PX.

11. 10. The method of claim 9, wherein determining the target operating speed of the low-pressure booster includes obtaining a target travel distance of fluid supplied to a low-pressure inlet of the PX, and the target operating speed of the low-pressure booster is based on an operating volume of the low-pressure booster, an operating volume of the PX, and the target travel distance.

12. The method comprises: and identifying a second indication of a temperature of an auxiliary gas cooler of the heat transfer system, the auxiliary gas cooler inlet configured to receive fluid from the high pressure outlet of the PX, the method further comprising: The method of claim 9, further comprising adjusting operation of a cooling component of the auxiliary gas cooler based on the second indication.

13. The method comprises: identifying first pressure data associated with a condenser of the heat transfer system; 10. The method of claim 9, further comprising: determining an operating speed of the PX based on the first pressure data.

14. The method comprises: determining a target opening value for a first valve based on the first indication of the operating speed of the PX, the inlet of the first valve being fluidly connected to a high pressure outlet of the PX, the method further comprising: The method of claim 9, further comprising causing actuation of the first valve based on the target opening value.

15. 1. A method, comprising: and identifying, by a processing device, first temperature data indicative of a temperature difference between a bulk fluid at a first inlet of a heat exchanger and the bulk fluid at a first outlet of the heat exchanger, the first outlet of the heat exchanger being fluidly connected to the first inlet by one or more fluid channels of the heat exchanger, the outlet of the heat exchanger being fluidly connected to a high pressure inlet of a pressure exchanger (PX), the method further comprising: determining a target adjustment of a first valve in fluid communication with the first outlet of the heat exchanger and a secondary fluid inlet of the heat exchanger based on the first temperature data; and causing actuation of the first valve based on the target adjustment.

16. Determining the target adjustment for the first valve comprises: determining that a subcooling value of the bulk fluid in the heat exchanger does not meet a subcooling threshold; and determining that the target adjustment to the first valve is predicted to adjust the subcooling value of the bulk fluid such that the subcooling meets a target subcooling condition.

17. 17. The method of claim 16, wherein determining the target adjustment to the first valve is predicted to adjust the subcooling value of the bulk fluid is based on a relationship between flow into the secondary fluid inlet and subcooling of the bulk fluid.

18. The method comprises: determining a target adjustment of a second valve based on the opening of the first valve in view of the target adjustment of the first valve, the inlet of the second valve being fluidly connected to a high pressure outlet of the PX, the method further comprising: The method of claim 15 , further comprising causing actuation of the second valve based on the target opening of the second valve.

19. 20. The method of claim 18, wherein determining the target adjustment of the second valve includes determining an opening of the second valve, the opening of the second valve providing a mass flow rate through the second valve that corresponds to a mass flow rate through the first valve based on the opening of the first valve.

20. 20. The method of claim 18, further comprising obtaining a system load of a heat transfer system including the PX, and determining a target opening degree of the second valve further based on the system load.

21. 20. The method of claim 18, wherein the method further includes obtaining second temperature data indicative of a temperature of fluid at the first outlet of the heat exchanger, and wherein determining a target opening of the second valve is further based on the second temperature data.

22. A non-transitory machine-readable storage medium storing instructions that, when executed, cause a processing device to perform the method of any one of claims 1 to 21.

23. 22. A system comprising: a memory; and a processing device coupled to the memory, the processing device configured to perform the method of any one of claims 1 to 21.

24. 1. A system comprising: a pressure exchanger (PX); a first condenser; a first valve; and 1. A heat exchanger comprising: a bulk inlet in fluid communication with the outlet of the first condenser; a bulk outlet in fluid communication with both the first valve and the high pressure inlet of the PX; and a heat exchanger including a secondary inlet in fluid communication with the first valve; a first temperature sensor configured to provide first temperature data associated with a temperature difference between a bulk fluid at the bulk inlet of the heat exchanger and the bulk outlet of the heat exchanger; a first controller operably coupled to the first valve, the first controller configured to operate the first valve based on the first temperature data.

25. 1. A system comprising: a pressure exchanger (PX); a first valve in fluid communication with the high pressure outlet of the PX; a first controller operably coupled to the first valve, the first controller configured to cause actuation of the first valve based on an operating speed of the PX.

26. 1. A system comprising: a pressure exchanger (PX); a low pressure booster having an outlet in fluid communication with the low pressure inlet of the PX; a first controller operably coupled to the low-pressure booster, the first controller configured to cause an adjustment of the operating speed of the low-pressure booster based on the operating speed of the PX.

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