Data center cooling systems including pressure exchangers

Abstract

The system includes a refrigeration system that exchanges heat between a first cooling loop and a second cooling loop. The refrigeration system includes a pressure exchanger (310) configured to receive a first fluid at a first pressure and a second fluid at a second pressure and to exchange pressure between the first and second fluids. The refrigeration system further includes a first heat exchanger (318) that exchanges heat between the first cooling loop and a portion of the first fluid discharged from the pressure exchanger. The refrigeration system further includes a second heat exchanger (329) that exchanges heat between a portion of the first fluid entering the pressure exchanger and the second cooling loop.

Description

[Technical Field]

[0001] The present disclosure relates to systems, and more particularly, to data center cooling systems that include pressure exchangers. [Background technology]

[0002] The system uses fluids at different pressures. The system uses pumps or compressors to increase the pressure of the fluids.

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

[0004] [Figure 1A] FIG. 1A shows a schematic diagram of a fluid treatment system including a hydraulic energy transfer system, according to certain embodiments. [Figure 1B] FIG. 1B shows a schematic diagram of a fluid treatment system including a hydraulic energy transfer system, according to certain embodiments. [Figure 1C] FIG. 1C shows a schematic diagram of a fluid treatment system including a hydraulic energy transfer system, according to certain embodiments. [Figure 2A] FIG. 2A is an exploded perspective view of a pressure exchanger (PX) according to certain embodiments. [Figure 2B] FIG. 2B is an exploded perspective view of a pressure exchanger (PX) according to certain embodiments. [Figure 2C] FIG. 2C is an exploded perspective view of a pressure exchanger (PX) according to certain embodiments. [Figure 2D] FIG. 2D is an exploded perspective view of a pressure exchanger (PX) according to certain embodiments. [Figure 2E] FIG. 2E is an exploded perspective view of a pressure exchanger (PX) according to certain embodiments. [Figure 3A] FIG. 3A is a schematic diagram of a data center cooling system including a pressure exchanger, according to certain embodiments. [Figure 3B]FIG. 3B is a schematic diagram of a data center cooling system including a pressure exchanger, according to certain embodiments. [Figure 3C] FIG. 3C is a schematic diagram of a data center cooling system including a pressure exchanger, according to certain embodiments. [Figure 4] FIG. 4 is a schematic diagram of a data center cooling system including a pressure exchanger, according to certain embodiments. [Figure 5A] FIG. 5A is a schematic diagram of a data center cooling system including a pressure exchanger, according to certain embodiments. [Figure 5B] FIG. 5B is a schematic diagram of a data center cooling system including a pressure exchanger, according to certain embodiments. [Figure 5C] FIG. 5C is a schematic diagram of a data center cooling system including a pressure exchanger, according to certain embodiments. [Figure 5D] FIG. 5D is a schematic diagram of a data center cooling system including a pressure exchanger, according to certain embodiments. [Figure 5E] FIG. 5E is a schematic diagram of a data center cooling system including a pressure exchanger, according to certain embodiments. [Figure 5F] FIG. 5F is a schematic diagram of a data center cooling system including a pressure exchanger, according to certain embodiments. [Figure 6] FIG. 6 is a flow diagram illustrating an exemplary method for controlling a data center cooling system, according to certain embodiments. [Figure 7] FIG. 7 is a block diagram illustrating a computer system in accordance with certain embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0005] Embodiments described herein relate to data center cooling systems that include pressure exchangers (e.g., data center cooling systems, fluid handling systems, heat transfer systems, pressure exchanger systems, carbon dioxide (CO2) refrigeration systems, etc.).

[0006] Systems use fluids at different pressures. These systems can include hydraulic fracturing (e.g., fracking or fracing) systems, desalination systems, refrigeration systems, air conditioning systems, data center cooling 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 can be used to increase the pressure of the fluids used by the systems.

[0007] Traditionally, refrigeration and / or air conditioning systems use compressors to increase the pressure of a fluid (e.g., a refrigeration fluid such as CO2, R-134a, hydrocarbons, hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), ammonia (NH3), refrigerant mixtures, R-407A, R-404A). Traditionally, a separate compressor mechanically coupled to a motor is used to increase the pressure of the fluid. Pumps and compressors that operate across a large pressure differential (e.g., causing a large pressure increase in the fluid) use a large amount of energy. Therefore, traditional systems consume a large amount of energy to increase the pressure of the fluid (via a pump or compressor driven by a motor). Additionally, traditional refrigeration systems reduce the pressure of the fluid via an expansion valve.

[0008] Conventional refrigeration systems introduce energy inefficiencies because fluids in the system undergo pressure reduction (e.g., expansion) through expansion valves while no useful work is extracted from the expanded fluid. Furthermore, hydrofluorocarbon (HFC) refrigerants (e.g., R-134a, R-404a, etc.) reportedly contribute to climate change and are being phased out by several countries. Traditional HFC refrigerants are being replaced with natural refrigerants such as CO2 (e.g., R-744), which have negligible environmental impact. However, the operating pressure of refrigeration systems using CO2 as a refrigerant is much higher than that of refrigeration systems using HFC refrigerants (e.g., 900 psi to 1500 psi (approximately 6.205 MPa to 10.342 MPa) compared with 200 psi to 300 psi (approximately 1.379 MPa to 2.068 MPa)). Therefore, refrigeration systems using CO2 refrigerants can consume significantly more energy than conventional refrigeration systems using HFC refrigerants. As ambient temperature increases, pressure in the gas cooler / condenser increases, and refrigeration systems using CO2 refrigerants experience more energy consumption when operated under warmer ambient conditions because the compressor has to work more to overcome the increased pressure. This is one of the major challenges associated with CO2 refrigeration systems. The disclosed system solves this challenge by extracting energy during the expansion of the high-pressure CO2 refrigerant and using the expanding refrigerant to compress a portion of the refrigerant flow, reducing the energy consumption of the refrigeration system's main compressor.

[0009] Air conditioning systems (e.g., refrigeration systems, etc.) are often used to cool data centers. Conventional air conditioning systems may be used to cool air provided within data center computer rooms to cool computer components such as servers and / or server components. However, conventional air conditioning systems used to cool data centers suffer from the same drawbacks as those discussed above, particularly inefficiencies during refrigerant expansion across large pressure differences. Large amounts of energy are used to operate conventional air conditioning systems for cooling data centers. This challenge is exacerbated by the increasing size of data centers and the increasing computational power of new computing components, which leads to increased heat emissions. The increased heat emissions of computing components with increased computational power and / or the increased size of data centers require increased cooling capacity that cannot be efficiently provided using conventional air conditioning systems.

[0010] The disclosed systems, devices, and methods provide a data center cooling system (e.g., a data center refrigeration system, etc.). In some embodiments, the data center cooling system includes a refrigeration system for exchanging heat between a first cooling loop and a second cooling loop. The first cooling loop can flow a first heat transfer fluid or coolant (e.g., water, a water-glycol mixture, etc.) to cool multiple servers (e.g., computing units, computing components, server components, etc.) located in a data center server room (e.g., a data center room, etc.). In some embodiments, the first cooling loop is configured to cool air within the data center. For example, the first cooling loop can cool a flow of air within the data center server room (e.g., a computer room, etc.) via a cooling coil (e.g., a cooling coil of a computer room air conditioner, etc.). Warm air from the servers can flow over the cooling coil (e.g., may be blown across the cooling coil by a fan). The warm air can be cooled, and the cooled air can be circulated within the server room and returned to the servers to cool them. Heat from the servers may be transferred from the warm air to the first cooling loop (eg, via a cooling coil).

[0011] In some embodiments, a first cooling loop provides heat from the servers to a refrigeration system (e.g., a data center cooling system having a pressure exchanger as described herein). In some embodiments, the refrigeration system provides heat from the servers to a second cooling loop. The second cooling loop may flow a second heat transfer fluid or coolant (e.g., water, a water-glycol mixture, etc.) to a cooling tower and / or chiller unit. In some embodiments, the cooling tower or chiller unit may reject heat from the second cooling loop to the ambient environment (e.g., a heat sink, etc.).

[0012] In some embodiments, a refrigeration system (e.g., a data center cooling system, a heat transfer system, a CO2 refrigeration system, etc.) flows a refrigerant (e.g., a CO2 refrigerant or other suitable refrigerant, etc.) along a refrigeration cycle. In some embodiments, the refrigeration system includes a pressure exchanger (PX) configured to exchange pressure between a first fluid (e.g., a high-pressure portion of the refrigeration fluid in the refrigeration cycle) and a second fluid (e.g., a low-pressure portion of the refrigeration fluid in the refrigeration cycle). In some embodiments, the PX can receive the first fluid (e.g., a portion of the refrigeration fluid that is at high pressure) via a first inlet (e.g., a high-pressure inlet) and the second fluid (e.g., a portion of the refrigeration fluid that is at low pressure) via a second inlet (e.g., a low-pressure inlet). In some embodiments, the first fluid is received at a high pressure from a second heat exchanger at the first inlet. Upon entering the PX, the first fluid may have a higher pressure than the second fluid. The PX can exchange pressure between the first fluid and the second fluid. A first fluid may exit the PX through a first outlet (e.g., a low-pressure outlet), and a second fluid may exit the PX through a second outlet (e.g., a high-pressure outlet). In some embodiments, the second fluid is provided to a first heat exchanger through the second outlet. Upon exiting the PX, the second fluid may have a higher pressure than the first fluid (e.g., due to pressure exchange between the first and second fluids).

[0013] In some embodiments, the data center cooling system includes a first heat exchanger for exchanging heat between a first cooling loop and a refrigeration system. The first cooling loop can provide heat from multiple servers to the first heat exchanger, where it can then be provided to the refrigeration system (e.g., heat is transferred from the first cooling loop to a refrigerated fluid in the first heat exchanger). The first heat exchanger can be an evaporator (e.g., evaporating a refrigerant from a liquid state to a gaseous state). In some embodiments, the first heat exchanger exchanges heat between the fluid of the first cooling loop and at least a portion of the first fluid discharged from the first outlet of the PX. The first heat exchanger can exchange heat between the refrigerant of the first cooling loop and at least a portion of the refrigerated fluid discharged from the first outlet of the PX. In some embodiments, the data center cooling system includes a second heat exchanger for exchanging heat between the refrigeration system and a second cooling loop. The refrigeration system can provide heat from the multiple servers to a second heat exchanger, where it can then be provided to a second cooling loop. In some embodiments, the second heat exchanger exchanges heat between at least a portion of the first fluid entering the first inlet of the PX and a fluid in the second cooling loop. The second heat exchanger can be a gas cooler (e.g., that cools a refrigerant in a gaseous state) or a condenser (e.g., that condenses a refrigerant from a gaseous state to a liquid state). The second cooling loop can carry the heat away to a cooling tower and / or chiller unit for heat disposal.

[0014] The disclosed systems, devices, and methods have advantages over conventional solutions. The disclosed systems may use a reduced amount of energy compared to conventional systems (e.g., provide data center cooling using reduced energy). The PX can enable the recovery of energy (e.g., pressure energy, etc.) within the refrigeration system that is typically lost in conventional systems. The recovered energy may be used to compress a portion of the refrigerant (e.g., in a vapor state) to a higher pressure (e.g., the operating pressure of a condenser or gas cooler). This reduces the amount of refrigerant compressed by the refrigeration system's main compressor, reducing the main compressor's energy consumption. This increases the efficiency of the disclosed systems, thereby using significantly less energy and costing end users less over time than conventional solutions. Furthermore, if electricity is generated by burning fossil fuels, the disclosed systems may reduce the carbon footprint of the data center cooling system. Additionally, the systems of the present disclosure reduce wear on components (e.g., pumps, compressors) compared to conventional systems because the pumps or compressors of the systems disclosed herein can operate more efficiently (e.g., the PX performs a portion of the fluid pressure increase, reducing the load on the pump and / or compressor) compared to conventional systems. Additionally, some systems described herein reduce the number of moving components (e.g., some systems use auxiliary coolers, receivers, etc. instead of boosters or compressors, etc.). This also allows the systems of the present disclosure to have increased reliability, reduced maintenance, increased component life, reduced system downtime, and increased yield (e.g., refrigeration, cooling, heating, etc.). The systems of the present disclosure may use pressure exchangers, which allow for longer life of system components, increase system efficiency, allow end users to choose from a wider range of pumps and / or compressors, reduce maintenance and downtime for service pumps and / or compressors, and enable new equipment and control devices.

[0015] 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 components, non-rotary pressure exchangers, or systems that do not include a pressure exchanger, etc.).

[0016] Although some embodiments of the present disclosure are described in the context of exchanging pressure between fluids used in data center cooling systems, data center refrigeration systems, 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.

[0017] FIG. 1A shows a schematic diagram of a fluid treatment system 100A including a hydraulic energy transfer system 110, according to certain embodiments.

[0018] In some embodiments, the hydraulic energy transfer system 110 includes a pressure exchanger (e.g., PX). The hydraulic energy transfer system 110 (e.g., PX) receives a low-pressure (LP) in fluid 120 from an LP in system 122 (e.g., via a low-pressure inlet). The hydraulic energy transfer system 110 also receives a high-pressure (HP) in fluid 130 from an HP in system 132 (e.g., via a high-pressure inlet). In some embodiments, the HP in system 132 exchanges heat with a cooling tower or chiller unit to reject heat to the surrounding environment (e.g., a heat sink). The hydraulic energy transfer system 110 (e.g., PX) exchanges pressure between the HP in fluid 130 and the LP in fluid 120 and provides an LP out fluid 140 to an LP out system 142 (e.g., via a low-pressure outlet) and an HP out fluid 150 to an HP out system 152 (e.g., via a high-pressure outlet). The controller 180 can cause one or more flow valves, pumps, and / or compressors (not shown) to regulate the flow rates of the HPin fluid 130 and the LPout fluid 140. The controller 180 can actuate the flow valves.

[0019] In some embodiments, hydraulic energy transfer 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 with an efficiency (e.g., pressure transfer efficiency, substantially isobaric) of greater than about 50%, 60%, 70%, 80%, 90%, or greater (e.g., without utilizing centrifugal methods). 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 in 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).

[0020] The PX may operate with the HPin fluid 130 directly pressurizing 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, pistons, bladders, diaphragms, etc. 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 movement of the rotor with respect to the end cover. In some embodiments, the rotary PX operates using internal pistons to isolate the fluids and transfer pressure with significantly less mixing of the inlet fluid streams. In some embodiments, the rotary PX operates without an internal piston between the fluids. A reciprocating PX may include a piston that moves back and forth within a cylinder to transfer pressure between the fluid streams. Any one or more PXs, such as, but not limited to, a rotary PX, a reciprocating PX, or any combination thereof, may be used in the present disclosure. The PX may also be located on a skid separate from other components of fluid treatment system 100A (e.g., when the PX is being added to an existing fluid treatment system). In some instances, the PX may be fixed to a structure that can be moved from one location to another. The PX may be coupled to a system (e.g., the system's pipes) that is constructed on-site.

[0021] In some embodiments, a motor 160 is coupled to the hydraulic energy transmission system 110 (e.g., to PX, to a rotor of 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, 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.

[0022] The hydraulic energy transfer system 110 may include a hydraulic pressure exchanger, such as a hydraulic turbocharger or 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).

[0023] In some embodiments, LPin system 122 includes a booster (e.g., a pump and / or a compressor) to increase the pressure of the fluid to form LPin fluid 120. In some embodiments, LPin system 122 includes an ejector to increase the pressure of the fluid to form LPin fluid 120. In some embodiments, LPin system 122 receives gas from LPout system 142. In some embodiments, LPin system 122 receives fluid from a receiver (e.g., a flash tank). The receiver may receive LPout fluid 140 discharged from hydraulic energy transfer system 110. In some embodiments, LPout system 142 exchanges heat with a data center server room to cool servers.

[0024] Fluid process system 100A may further include one or more sensors that provide sensor data (e.g., flow rate data, pressure data, velocity data, etc.) associated with the fluid in fluid process system 100A. Controller 180 may control one or more flow rates in fluid process system 100A based on the sensor data. In some embodiments, controller 180 actuates one or more flow valves based on the received sensor data. In some embodiments, controller 180 may perform the method of FIG. 6.

[0025] 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 a refrigeration system, such as a data center cooling system. In some implementations, fluid treatment system 100B is a thermal energy (e.g., heat) transport system (e.g., a thermal, heat transport system). Fluid treatment system 100B may be configured to cool an environment (e.g., an indoor space, a refrigeration unit, a freezer, a data center server room, etc.). In some embodiments, fluid treatment system 100B includes more components, fewer components, the same routing, different routing, and / or the like than those shown in FIG. 1B. Some of the features in FIG. 1B that have similar reference numbers as FIG. 1A may have similar properties, functions, and / or structures as FIG. 1A.

[0026] The hydraulic energy transfer system 110 (e.g., PX) may receive an LPin fluid 120 from an LPin system 122 (e.g., low-pressure lift device 128, low-pressure fluid pump, low-pressure booster, low-pressure compressor, low-pressure ejector) and an 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 to provide an HPout fluid 150 to an HPout system 152 (e.g., high-pressure lift device 159, high-pressure fluid pump, high-pressure booster, high-pressure compressor, high-pressure ejector) and provide an LPout fluid 140 to an LPout system 142 (e.g., evaporator 144, heat exchanger, receiver 113). LPout system 142 (e.g., evaporator 144, receiver 113) may provide fluid to compressor 178 and low-pressure lift device 128. Evaporator 144 may provide fluid to compressor 178, and receiver 113 (e.g., a flash tank) may provide fluid to low-pressure lift device 128. Condenser 138 may receive fluid from compressor 178 and high-pressure lift device 159. High-pressure lift device 159 may be a high-pressure booster, and low-pressure lift device 128 may be a low-pressure booster.

[0027] In some embodiments, the evaporator 144 receives heat from a computer room air conditioner (CRAC) 146 via a first cooling loop 186. The first cooling loop 186 can carry heat from multiple servers in a server room (e.g., cooled by the CRAC 146). The refrigerant in the first cooling loop 186 can be cooled in the evaporator 144 and circulated to the CRAC 146. The CRAC 146 can use the cooled refrigerant to cool the air in the server room and cool the servers. In some embodiments, the cooling tower 136 receives heat from the condenser 138 via a second cooling loop 170. The second cooling loop 170 can carry heat from multiple servers in the server room. The refrigerant in the second cooling loop 170 can be heated in the condenser 138 and circulated to the cooling tower 136. The refrigerant in the second cooling loop 170 can be cooled by the cooling tower 136. The cooled coolant may be recycled from the cooling tower 136 to the condenser 138. A controller 180 may control one or more components of the fluid treatment system 100B.

[0028] Fluid treatment system 100B may be a closed system. LPin fluid 120, HPin fluid 130, LPout fluid 140, and HPout fluid 150 may all be fluids (e.g., refrigerants, the same fluid) that are circulated within the closed system of fluid treatment system 100B.

[0029] Fluid treatment system 100B may further include one or more sensors configured to provide sensor data associated with the fluid. One or more flow valves may control the flow rate of the fluid based on the sensor data received from the one or more sensors. In some embodiments, one or more pressure control valves may be included in system 100B to separate higher pressure fluid from lower pressure fluid. In some embodiments, system 100B may also include a flash tank or receiver for receiving a two-phase liquid-vapor mixture and separating the mixture into liquid and vapor portions using density differences. The liquid portion may be provided to an evaporator after reducing its pressure through a valve (e.g., an expansion valve). The vapor portion may be provided to low-pressure lift device 128. Excess gas not received by low-pressure lift device 128 may be sent to compressor 178 after reducing its pressure through a valve (e.g., an expansion valve) to the operating pressure of evaporator 144. In some embodiments, controller 180 operates one or more flow valves (not shown) based on the received sensor data.

[0030] FIG. 1C shows a schematic diagram of a fluid treatment system 100C including a hydraulic energy transfer system 110, according to certain embodiments. Fluid treatment system 100C may be a cooling system, such as a data center cooling system. In some implementations, fluid treatment system 100C is a thermal energy (e.g., heat) transport system (e.g., a heat transport system). Fluid treatment system 100C may be configured to cool an environment (e.g., an indoor space, a refrigeration unit, a freezer, a data center server room, etc.). In some embodiments, fluid treatment system 100C includes more components, fewer components, the same routing, different routing, and / or the like than those shown in FIG. 1C. Some of the features in FIG. 1C having similar reference numbers as FIG. 1A may have similar properties, functions, and / or structures as those in FIGS. 1A and 1B.

[0031] In some embodiments, refrigeration system 164 is for cooling servers in data center 190. Refrigeration system 164 can cool the servers in data center 190 by cooling the air within data center 190 and / or by cooling a liquid coolant. Multiple servers may be disposed within data center 190. For example, data center 190 may include one or more rooms, each room including one or more racks that each support multiple servers. In some embodiments, refrigeration system 164 includes hydraulic energy transfer system 110 (e.g., a pressure exchanger, etc.) and compressor 178, as described herein. In some embodiments, refrigeration system 164 includes first heat exchanger 118 and second heat exchanger 129. Heat exchanger 118 can exchange heat between fluid (e.g., at least a portion of the fluid) discharged from hydraulic energy transfer system 110 and fluid in first cooling loop 186. The cooling loop 186 can provide chilled coolant to cool the servers in the data center 190. Heat from the servers can be transferred by the cooling loop 186 to the heat exchanger 118. In some embodiments, heated refrigerated fluid flows from the first heat exchanger 118 to the second heat exchanger 129. A flow of refrigerated fluid to or from the hydraulic energy transfer system 110 can be provided. In some embodiments, the second heat exchanger 129 exchanges heat between the fluid entering the hydraulic energy transfer system 110 and the fluid in the second cooling loop 170. The heat can be transferred by the second cooling loop 170 to the cooling tower 174 to cool the coolant. The cooled coolant can be returned by the second cooling loop 170 to the second heat exchanger 129. In some embodiments, the cooled refrigerated fluid flows from the second heat exchanger 129 to the hydraulic energy transfer system 110. Several possible configurations of fluid treatment system 100C are shown and described herein with reference to Figures 3A-3C, 4, and 5A-5F.

[0032] 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.

[0033] The PX 40 is configured to transfer pressure and / or work between a first fluid (e.g., refrigerant, supercritical carbon dioxide, HPin fluid 130) and a second fluid (e.g., refrigerant, superheated gaseous carbon dioxide, LPin fluid 120) with minimal fluid mixing. The rotary PX 40 may include a generally cylindrical body portion 42 including a sleeve 44 (e.g., rotor sleeve) and a rotor 46. The rotary PX 40 may also include two end caps 48 and 50 including 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 subsequently exit the rotary PX 40. During operation, the inlet port 56 may receive a high-pressure first fluid (e.g., HPin fluid 130) exiting the condenser, and after exchanging pressure, the outlet port 58 may be used to route a low-pressure first fluid (e.g., LPout fluid 140) exiting 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 may form a chamber configured to separate the fluid into gas and liquid. Similarly, the 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 the outlet port 62 may be used to route the high-pressure second fluid (e.g., high-pressure slurry fluid, HPout fluid 150) out of the rotary PX 40. End caps 48 and 50 include respective end covers 64 and 66 (eg, end plates) disposed within respective manifolds 52 and 54 that provide fluid-sealing contact with rotor 46 .

[0034] One or more components of PX 40, 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, ceramics such as alumina ceramic) having a hardness above a predetermined threshold (e.g., a Vickers hardness number of at least 1000, 1250, 1500, 1750, 2000, 2250, or greater). In some examples, tungsten carbide may be more durable and provide improved wear resistance to abrasive fluids compared to other materials, for example, compared to alumina ceramic. Additionally, in some embodiments, one or more components of PX 40, such as rotor 46, end cover 64, end cover 66, and / or other sealing surfaces of PX 40, 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.

[0035] The rotor 46 may be cylindrical and disposed within the sleeve 44, thereby enabling the rotor 46 to rotate about the axis 68. The rotor 46 may have a plurality of channels 70 (e.g., ducts, rotor ducts) symmetrically disposed about the longitudinal axis 68 and extending substantially longitudinally therethrough with openings 72 and 74 (e.g., rotor ports) at each end. The openings 72 and 74 in the rotor 46 are arranged in hydraulic communication with inlet and outlet apertures 76 and 78 (e.g., end cover inlet and outlet ports) and 80 and 82 (e.g., end cover inlet and outlet ports) in the end covers 64 and 66, respectively, in such a way that the channels 70 are exposed to high-pressure 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).

[0036] In some embodiments, a controller (e.g., controller 180 of FIGS. 1A-B) using sensor data (e.g., revolutions per minute measured via a tachometer or optical encoder, volumetric flow rate measured via a flow meter, etc.) can 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). In some examples, by varying the volumetric flow rates of the first and / or second fluids entering the rotary PX 40, an operator (e.g., system operator, plant operator) can control the amount of fluid mixing within the PX 40. Additionally, an operator can control mixing by varying the rotational speed of the rotor 46 (e.g., via a motor). 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 formation 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, stabilizing 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. In some examples, 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, rotor channel 70 (e.g., a small portion of rotor channel 70) is used for pressure exchange between the first and second fluids. In some embodiments, a volume of fluid remains within channel 70 as a barrier between the first and second fluids. All of these mechanisms can limit mixing within 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.

[0037] 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 simplifications of the rotary PX 40 showing one rotor channel 70, and the channel 70 is shown as having a circular cross-section. 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 simplifications 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 come into short contact with 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 (once the channel is exposed to the aperture 76), the diffusion rate of the fluids, and / or the rotational speed of the rotor 46 can govern whether and to what extent mixing occurs.

[0038] FIG. 2B is an exploded perspective view of an embodiment of the rotary PX 40, according to certain embodiments. In FIG. 2B, the 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 therefore with the manifold 52, while the opposite channel opening 74 is in fluid communication with an aperture 82 in the end cover 66 and therefore with the manifold 54. The rotor 46 can rotate in a clockwise direction, as indicated by arrow 84. During 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, due to the short contact time, 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 side of the partition). The second fluid 86 drives a barrier to force 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.

[0039] 2C is an exploded perspective view of an embodiment of a rotatable PX 40, 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.

[0040] Figure 2D is an exploded perspective view of an embodiment of a rotating PX 40, according to certain embodiments. In Figure 2D, the channel 70 has rotated through a first predetermined arc angle (e.g., an approximately 60-degree arc) from the position shown in Figure 2B. The opening 74 is now 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 high-pressure first fluid 88 enters and pressurizes a low-pressure second fluid 86, driving the second fluid 86 out of the rotor channel 70 and through the aperture 80.

[0041] Figure 2E is an exploded perspective view of an embodiment of a rotary PX 40, according to certain embodiments. In Figure 2E, channel 70 has rotated through a second predetermined angle or arc (e.g., an arc of approximately 270 degrees) from the position shown in Figure 2B. In this position, opening 74 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. Therefore, first fluid 88 is no longer pressurized and is temporarily contained within channel 70 until rotor 46 rotates another 90 degrees and the cycle begins again.

[0042] 3A-C are schematic diagrams of data center cooling systems 300A-C including pressure exchangers, according to certain embodiments. Some of the features in one or more of Figures 3A-C may have similar properties, functions, and / or structures as those in one or more of Figures 1A-B and / or one or more of Figures 2A-E. The systems of Figures 3A-C and / or one or more of Figures 4-5 may be used to perform the method of Figure 6.

[0043] FIG. 3A is a schematic diagram of a data center cooling system 300A including a PX 310, according to certain embodiments. In some embodiments, the data center cooling system 300A is a thermal energy transport system and / or a fluid handling system. The PX 310 may be a rotary pressure exchanger. In some embodiments, the PX 310 is an isobaric or substantially isobaric pressure exchanger. The PX 310 may be configured to exchange pressure between a first fluid and a second fluid. In some embodiments, the PX 310 is coupled to a motor 360 (e.g., the rotation of a rotor of the PX 310 is controlled by the motor 360). In some embodiments, the motor 360 controls the rotational speed of the PX 310. The mass flow rate (e.g., of the first fluid and / or the second fluid) through the PX 310 may be related to the rotational speed of the PX 310. In some embodiments, the pressure of a fluid (e.g., the first fluid) in the gas cooler 329 may be related to the rotational speed of the PX 310. In some embodiments, a controller (eg, controller 380 ) receives sensor data from one or more sensors of motor 360 .

[0044] In some embodiments, the PX 310 is adapted 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 adapted to receive a second fluid at low pressure (e.g., LPin fluid 120 in FIGS. 1A-B) via a low-pressure inlet. Although there is reference to "high pressure" and "low pressure," "high pressure" and "low pressure" may be relative to each other 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, etc.). The PX 310 may exchange pressure between the first and second fluids. The PX 310 may provide a first fluid (e.g., LPout fluid 140) via a low-pressure outlet and a second fluid (e.g., HPout fluid 150) via a high-pressure outlet. In some embodiments, the first fluid provided via the low-pressure outlet is at low pressure, and the second fluid provided via the high-pressure outlet is at high pressure.

[0045] In some embodiments, the PX 310 is a rotary PX with multiple ducts. In some embodiments, a low-pressure gas refrigerant (e.g., a second fluid at a second pressure) enters a duct and is sealed within the duct as the duct rotates past a low-pressure inlet port. When the duct is exposed to a high-pressure outlet port, a pressure wave is generated that compresses the low-pressure gas refrigerant to a high pressure. As the low-pressure gas refrigerant is compressed, its temperature may increase. Thus, the low-pressure gas refrigerant may be converted to a high-pressure, high-temperature refrigerant (e.g., a supercritical state). The high-pressure, high-temperature (e.g., supercritical) refrigerant (e.g., a second fluid at a fourth pressure) may be expelled from the duct through a high-pressure outlet port when a high-pressure, medium-temperature supercritical refrigerant (e.g., a first fluid at a first pressure) enters the opposite end of the duct (e.g., from a high-pressure inlet port). The high-pressure, medium-temperature supercritical refrigerant may push a compressed fluid plug out of the high-pressure outlet port. Then, as the duct continues to rotate past the high-pressure inlet port, a high-pressure, medium-temperature fluid plug may be sealed within the duct. When the duct is exposed to the low-pressure outlet port, an expansion wave propagates through the duct, converting the high-pressure, medium-temperature supercritical refrigerant into a low-pressure, low-temperature two-phase vapor-liquid mixture (e.g., a first fluid at a third pressure), which may then be ejected out of the duct through the low-pressure outlet port.

[0046] In some embodiments, the fluid treatment system 300A includes a gas cooler 329 (e.g., a condenser, etc.), an evaporator 318, and a compressor 322. In some embodiments, the gas cooler 329 is a heat exchanger that provides heat from a refrigerant (e.g., a first fluid) to a cooling loop (e.g., a second cooling loop 370). The gas cooler 329 can remove heat from the refrigerant and provide the heat to the cooling loop. In some embodiments, the gas cooler 329 is a heat exchanger that cools a fluid flowing through the gas cooler 329 (e.g., cools a refrigerant in a gaseous state, etc.). In some embodiments, the gas cooler 329 is a heat exchanger that condenses a fluid flowing through the gas cooler 329 from a gaseous state to a liquid state (e.g., cooling the flowing fluid). In some embodiments, the pressure of the fluid in the gas cooler 329 exceeds the critical pressure of the fluid. The gas cooler 329 can provide heat from a fluid (e.g., gas) to the second cooling loop 370. In some embodiments, the temperature of the fluid in the gas cooler 329 decreases, but the fluid does not condense (e.g., the fluid does not change from a vapor to a liquid phase). In some embodiments, the critical pressure of the fluid (e.g., of the refrigerant) is exceeded, and the thermodynamic distinction between the liquid and vapor phases of the fluid in the gas cooler 329 disappears, and only a single fluid state exists, referred to as the supercritical state.

[0047] In some examples, the evaporator 318 can provide heat received by the system 300A to a refrigerated fluid from the first cooling loop 386. In some embodiments, the refrigerated fluid is CO2 or other refrigerated fluid. The heat can be rejected to the second cooling loop 370 via a gas cooler 329. In some embodiments, the heat received by the system 300A is excess heat from multiple servers (e.g., computing units, server components, etc.) located in a server room 390A. Details regarding cooling multiple servers in the server room 390A are discussed below.

[0048] The compressor 322 can increase the corresponding pressure of the refrigeration fluid along the flow path between the evaporator 318 and the gas cooler 329. The refrigeration fluid can flow substantially in a cycle (e.g., from the gas cooler 329 to the PX 310 to the evaporator 318 to the compressor 322 to the gas cooler 329, etc.). It is preferred that all fluid entering the compressor 322 be in a gaseous state (e.g., a superheated gaseous state) and that no liquid enter the compressor 322. By preventing liquid from entering the compressor 322, damage to the compressor 322 can be minimized (e.g., because liquids are incompressible).

[0049] In some embodiments, fluid treatment system 300A includes a low-pressure booster (e.g., LP booster 314) and / or a high-pressure booster (e.g., HP booster 324). Both LP booster 314 and HP booster 324 may be configured to increase (e.g., “boost”) the pressure of a second fluid. For example, low-pressure booster 314 may increase the pressure of the second fluid discharged from evaporator 318 (e.g., received from PX 310). HP booster 324 may increase the pressure of the second fluid discharged by PX 310. The second fluid may be provided (e.g., by HP booster 324), combined with the fluid discharged from compressor 322 (e.g., upstream of the inlet of gas cooler 329), and provided to gas cooler 329. LP booster 314 may increase the pressure below a threshold amount (e.g., LP booster 314 may operate across a pressure differential below a threshold amount). In some examples, the low-pressure booster 314 can increase the second pressure by approximately 10 to 60 psi (approximately 68.95 to 413.69 kPa). The second fluid may experience a pressure loss (e.g., due to fluid friction losses in the piping) as the second fluid flows from the LP booster 314 to the second inlet of the PX 310. The HP booster 324 can increase the pressure of the second fluid between the second outlet of the PX 310 and the inlet of the gas cooler 329. The HP booster 324 can increase the pressure below a threshold amount (e.g., the HP booster 324 can operate across a pressure differential below a threshold amount). In some examples, the high-pressure booster 324 can increase the pressure of the second fluid by approximately 10 to 60 psi (approximately 68.95 to 413.69 kPa). HP booster 324 can increase the pressure of the second fluid to a pressure that substantially matches the pressure of the fluid discharged from compressor 322 (e.g., the pressure of gas cooler 329). In contrast to LP booster 314 and HP booster 324, compressor 322 increases the pressure of the fluid above a threshold amount (e.g., compressor 322 can operate across a pressure differential that exceeds a threshold amount).In some examples, the compressor 322 can increase the pressure of the fluid to greater than about 200 psi (about 1.379 MPa). In some embodiments, the controller 380 controls the flow rate of the fluid through the PX 310 by controlling the flow rate of the LP booster 314. In some examples, the controller 380 can set the flow rate of the LP booster 314 to control the flow rate of the first fluid through the PX 310.

[0050] In some embodiments, the evaporator 318 is a heat exchanger for exchanging (e.g., providing) corresponding thermal energy from the first cooling loop 386 to the refrigerating fluid. The refrigerating fluid may transition from a liquid state to a vapor state (e.g., a gaseous state) within the evaporator 318. In some examples, the evaporator 318 may receive heat (e.g., thermal energy) from a coolant (e.g., a heat transfer fluid, water, a water-glycol mixture, etc.) of the first cooling loop and provide the heat to the refrigerating fluid. In some embodiments, this heat is excess heat from servers located in racks 399 within the server room 390A. In some embodiments, air circulating within the server room 390A is used to cool the servers (e.g., server components, etc.). In some embodiments, the circulating air 398 carries heat away from the servers and is directed into the CRAC 391. The CRAC 391 may be a cooler unit for cooling the air 398. A fan 392 can direct air 398 through / pass an optional humidifier 394. The humidifier 394 can add moisture to the air 398. In some embodiments, the fan 392 directs air through a cooling coil 396. In some embodiments, the cooling coil 396 is a heat exchanger (e.g., a brazed plate heat exchanger, a shell-and-tube heat exchanger, etc.) configured to exchange heat between the air 398 and the coolant of the first cooling loop 386. In some embodiments, heat from the air 398 is provided to the coolant of the first cooling loop 386 via the cooling coil 396. In some embodiments, a pump 388 is configured to pump the coolant along the flow path of the first cooling loop 386 between the cooling coil 396 and the evaporator 318. Heat from the servers can be provided to the evaporator 318 by the first cooling loop 386. In some embodiments, the air 398 is cooled by the coolant via the cooling coil 396. In some embodiments, cooled air 398 is routed (e.g., via ducting) from CRAC 391 to the space below raised floor 397. The cooled air 398 then passes through perforations in raised floor 397 and rises between the servers in racks 399 to cool the servers.Warm air 398 is then delivered to CRAC 391. In some embodiments, raised floor 397 is configured to support multiple server racks 399, each server rack supporting multiple servers.

[0051] In some embodiments, the gas cooler 329 is a heat exchanger that transfers corresponding thermal energy (e.g., heat) between the refrigerating fluid and the second cooling loop 370. In some embodiments, the gas cooler 329 provides thermal energy from the refrigerating fluid to a coolant (e.g., a heat transfer fluid, water, a water-glycol mixture, etc.) of the second cooling loop 370. In some embodiments, the heat transferred by the gas cooler 329 to the second cooling loop 370 corresponds to the heat transferred from the first cooling loop 386 in the evaporator 318 (e.g., heat from the servers in the server room 390A). In some embodiments, a pump 372 circulates the coolant along the flow path of the second cooling loop 370 between the gas cooler 329 and a cooling tower 374. The cooling tower 374 may be a cooling tower or a chiller unit. In some embodiments, the cooling tower 374 receives the warm coolant and cools it by rejecting heat from the coolant to the ambient environment. The ambient environment may be a cold sink for rejecting heat. The cooled coolant may flow from the cooling tower 374 to the gas cooler 329.

[0052] In some embodiments, the temperature and / or humidity of the ambient environment affect the performance of the cooling tower 374. The performance of the cooling tower 374 can affect the performance of the system 300A. For example, the cooling tower 374 can cool the refrigerant in the second cooling loop 370 to a temperature determined by the relative humidity and / or temperature of the ambient environment. The refrigerant flowing through the gas cooler 329 is not cooled to a temperature lower than the temperature of the refrigerant in the second cooling loop 370. Cooling the refrigerant in the gas cooler 329 to a lower temperature can more efficiently cool the refrigerant in the first cooling loop 386 in the evaporator 318. If the temperature of the refrigerant exiting the gas cooler 329 is lower, the refrigerant is closer to a saturated liquid state after expanding through the PX 310, meaning that the refrigerant contains more liquid in the saturated mixture. Liquid refrigerant provides greater cooling capacity when flowing through the evaporator 318 compared to gaseous refrigerant. Therefore, by lowering the temperature of the refrigerant (e.g., cooled by a cooling tower 374) in the second cooling loop 370, more heat absorption (e.g., by the refrigerant) is possible in the evaporator 318, leading to increased efficiency of the system 300A.

[0053] System 300A may include a controller 380 (e.g., controller 180 of FIGS. 1A-1D). Controller 380 may control a booster and / or a compressor of system 300A. Controller 380 may receive sensor data from one or more sensors of system 300A. The sensors may include pressure sensors, flow sensors, and / or temperature sensors. In some embodiments, controller 380 controls a motor (e.g., motor 360) coupled to PX 310. In some embodiments, controller 380 receives motor data from one or more motor sensors associated with motor 360. The motor data received from the motor sensors may include a current motor speed (e.g., revolutions per minute), total motor run time, motor run time between maintenance operations, and / or total motor revolutions. The motor data may be indicative of the performance status of the motor.

[0054] In some embodiments, controller 380 receives sensor data indicative of the temperature of the coolant in first cooling loop 386 and / or the temperature of air 398 in server room 390A. Controller 380 may control LP booster 314, HP booster 324, and / or compressor 322 based on sensor data received from one or more sensors (e.g., one or more fluid flow sensors, temperature sensors, pressure sensors, etc.) in system 300A. In some embodiments, one or more sensors (e.g., pressure sensors, flow sensors, temperature sensors, etc.) are positioned near the inlets and / or outlets of various components of system 300A. In some embodiments, one or more sensors are positioned internal to components of system 300A. In some examples, a pressure sensor may be positioned near the inlet of compressor 322, and an additional pressure sensor may be positioned near the outlet of compressor 322. In some examples, a temperature sensor may be positioned near the inlet of evaporator 318, and another temperature sensor may be positioned near the outlet of evaporator 318. In some examples, a temperature sensor may be located inside the gas cooler 329. In some examples, a flow sensor may be located at each of 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.

[0055] References to a "first fluid" and a "second fluid" are made herein. In some embodiments, the first fluid and the second fluid are the same type of fluid (e.g., a refrigeration fluid flowing within a fluid processing system). A "first fluid" may refer to a fluid flowing through PX310 from its high-pressure inlet to its low-pressure outlet, and / or a fluid flowing to or from the high-pressure inlet and / or low-pressure outlet of PX310. A "second fluid" may refer to a fluid flowing through PX310 from its low-pressure inlet to its high-pressure outlet, and / or a fluid flowing to or from the low-pressure inlet and / or high-pressure outlet of PX310. 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., CO2 vapor). In some embodiments, the second fluid may be a two-phase refrigerant fluid (e.g., a gas-liquid mixture of CO2). In some embodiments, the second fluid may be a liquid refrigerant fluid (e.g., liquid CO2).

[0056] 3B is a schematic diagram of a data center cooling system 300B including a PX 310, according to certain embodiments. In some embodiments, features having similar reference numbers to those in other figures include similar properties, structures, and / or functions as those described in the other figures. In some examples, features of system 300B have similar properties, structures, and / or functions as system 300A of FIG. 3A.

[0057] In some embodiments, system 300B provides cooling for servers located in server room 390B. In some embodiments, cool air 398 is provided to racks 399 by CRAC 391. The servers may be located within racks 399. In some embodiments, cool air 398 receives heat from the servers (e.g., from server components) and flows upward in hot aisle 395. In some embodiments, hot aisle 395 is the space between two racks 399. In some embodiments, hot aisle 395 separates heated air from cooled air, allowing servers to be cooled more efficiently. Hot aisle 395 may direct heated air away from the cooled air and / or away from the servers. In some embodiments, ducting routes heated air 398 from the hot aisle 395 to the intake of the CRAC 391 (e.g., via a humidifier 394 and / or cooling coil 396, etc.) for cooling and / or conditioning.

[0058] 3C is a schematic diagram of a data center cooling system 300C including a PX 310, according to certain embodiments. In some embodiments, features having similar reference numbers to those in other figures include similar properties, structures, and / or functions as those described in the other figures. In some examples, features of system 300C have similar properties, structures, and / or functions as system 300A of FIG. 3A and / or system 300B of FIG. 3B.

[0059] In some embodiments, system 300C provides cooling to servers located in server room 390C. In some embodiments, warm air 398 from server room 390C is routed (e.g., via ducting) to CRAC 391. In some embodiments, CRAC 391 includes an evaporator 318. In some embodiments, warm air 398 exchanges heat with a refrigerant via evaporator 318. In some embodiments, evaporator 318 is configured to cool air 398 circulating through server room 390C. The refrigerant flowing through evaporator 318 may be heated, and air 398 may be cooled. In some embodiments, cooled air 398 is routed (e.g., via ducting) from CRAC 391 to a space below a raised floor 397 of server room 390C. In some embodiments, air 398 flows upward through racks 399 through perforations in raised floor 397, cooling the servers. Warm air 398 that carries heat away from the servers is routed to CRAC 391, which provides heat from the servers to the refrigerant via evaporator 318. In some embodiments, this heat is rejected to the ambient environment directly by gas cooler 329 (e.g., without the use of a cooling loop or cooling tower). Fan 331 can force air across gas cooler 329 (e.g., across the fins of gas cooler 329) to help reject heat from the refrigerant to the ambient environment. In some embodiments, system 300C can be used when cost reduction is a consideration and / or when the data center operates in a cold (e.g., colder) climate, such as an arctic climate.

[0060] 4 is a schematic diagram of a data center cooling system 400 including a PX 310, according to certain embodiments. In some embodiments, features having similar reference numbers to those in other figures include similar properties, structures, and / or functions as those described in the other figures. In some examples, features of system 400 have similar properties, structures, and / or functions as system 300A of FIG. 3A. In some embodiments, system 400 may include any of server rooms 390A, 390B, and / or 390C, as shown in FIGS. 3A-3C.

[0061] In some embodiments, the system 400 includes a flash tank 313 (e.g., a receiver, etc.). In some embodiments, the flash tank 413 is a receiver configured to receive a flow of fluid (e.g., a first fluid) discharged from the low-pressure outlet of the PX 310. The flash tank 413 may form a chamber that collects the first fluid from the first outlet of the PX 310. The flash tank 413 may receive the first fluid in a two-phase state (e.g., liquid and gas). In some embodiments, the flash tank 413 is a tank constructed of welded sheet metal. The flash tank 413 may be made of steel (e.g., sheet metal, steel plate, etc.). The first fluid (e.g., at low pressure) may separate into gas and liquid within the flash tank 413. The liquid may settle to the bottom of the flash tank 413, while the gas may rise to the top of the flash tank 413. The liquid may flow from the flash tank 413 toward the evaporator 318 (e.g., via an expansion valve 416). The chamber of flash tank 413 may be maintained at a set pressure. The pressure may be set by a user (e.g., an operator, technician, engineer, etc.) and / or a controller (e.g., controller 380). In some embodiments, the pressure of flash tank 413 is controlled by one or more valves (e.g., flush gas valve 420, pressure regulator valve, safety valve, etc.). In some embodiments, flash tank 413 includes at least one pressure sensor (e.g., a pressure transducer).

[0062] In some embodiments, the system 400 includes an expansion valve 416. In some embodiments, the expansion valve 416 is disposed along a flow path between the flash tank 413 and the evaporator 318. The expansion valve 416 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.). The expansion valve 416 may be controllable by a user (e.g., a technician, an operator, an engineer, etc.) or by the controller 380. In some embodiments, the expansion valve 416 is actuated by the controller 380 based on sensor data (e.g., pressure sensor data, flow sensor data, temperature sensor data, etc.). In some embodiments, the expansion valve 416 is a thermal expansion valve. The expansion valve 416 may be actuated (e.g., opened or closed) based on temperature data associated with the evaporator 318 (e.g., temperature data of the refrigerating fluid exiting the evaporator). In some examples, a sensing bulb (e.g., a temperature sensor, a temperature-dependent pressure sensor, etc.) of the expansion valve 416 can increase or decrease pressure on the diaphragm of the expansion valve 416, causing a poppet valve coupled to the diaphragm to open or close, thereby causing more or less fluid flow to the evaporator 318 and more or less expansion of the fluid. The expansion valve sensing bulb can be located near the downstream end of the evaporator 318 (e.g., near the fluid outlet of the evaporator 318) and can be fluidly connected to the diaphragm via a sensing capillary (e.g., a conduit between the sensing bulb and the expansion valve 416). In some embodiments, the expansion valve 416 is controlled and / or actuated entirely based on electronic commands (e.g., from the controller 380). In some embodiments, the enthalpy of the refrigerant flowing through the expansion valve 416 is equal on the upstream and downstream sides of the valve. Therefore, the enthalpy of the liquid refrigerant exiting the flash tank 413 may be equal to the enthalpy of the refrigerant entering the evaporator 318 .

[0063] In some embodiments, the system 400 includes a flash gas valve 420 to regulate the flow of gas on a flash gas bypass flow path. In some embodiments, the flash gas valve 420 is a bypass valve that regulates the flow of gas from the gas outlet of the flash tank 413 to combine with the discharge of the evaporator 318. In some embodiments, the flow of gas from the flash tank 413 flows along the flash gas bypass flow path and bypasses the evaporator 318. In some embodiments, the flash gas flow path is between the flash tank 413 and a location downstream of the outlet of the evaporator 318. The gas flowing along the flash gas bypass flow path may be combined with the discharge of the evaporator 318. The flash gas valve 420 may expand (e.g., reduce pressure) the gas collected in the flash tank 413 as the gas flows toward the compressor 322. In some embodiments, the flash gas valve 420 may be an adjustable valve. In some embodiments, the flash gas valve 420 is operated by the controller 380 based on sensor data.

[0064] In some embodiments, the LP booster 314 receives a fluid flow from the flash tank 413. In some embodiments, the LP booster 314 receives a gas flow from the flash tank 413. In some examples, the LP booster 314 receives a portion of the gas flowing along the flash gas bypass flowpath between the flash tank 413 and the flash gas valve 420. In some embodiments, the low-pressure booster 314 receives a fluid and increases the pressure of the fluid to form a second fluid (e.g., at a second pressure). The fluid is provided at the increased pressure (e.g., the second pressure) as the second fluid to the second inlet of the PX 310. In some embodiments, the LP booster 314 is a compressor or pump operating at a low pressure differential to “boost” the pressure of the gas received from the flash tank 413. In some embodiments, the HP booster 324 is a compressor or pump operating at a low pressure differential to “boost” the pressure of the fluid (e.g., the second fluid) received from the second outlet of the PX. In some embodiments, the compressor is configured to increase the pressure of a fluid that consists essentially of a gas, while the pump is configured to increase the pressure of a fluid that consists essentially of a liquid.

[0065] 5A-5F are schematic diagrams of data center cooling systems 500A-500F including pressure exchangers, according to certain embodiments. Referring to FIG. 5A, a schematic diagram of a data center cooling system 500A including a PX 310 is shown, according to certain embodiments. In some embodiments, features having similar reference numbers to those in other figures include similar properties, structures, and / or functions as those described in the other figures. In some examples, features of system 500A have similar properties, structures, and / or functions as systems 300A-3C of FIGS. 3A-3C and system 400 of FIG. 4. In some embodiments, system 500A may include any of server rooms 390A, 390B, and / or 390C, as shown in FIGS. 3A-3C.

[0066] In some embodiments, the system 500A includes a parallel valve 548. The parallel valve 548 may be an expansion valve or a flow control valve. In some embodiments, the parallel valve 548 selectively regulates the flow of fluid from the outlet of the gas cooler 329 to the flash tank 413 in parallel with the PX 310. In some embodiments, the parallel valve 548 controls the pressure of the gas cooler 329 (e.g., gas cooler) by selectively opening and closing its orifice (e.g., of the parallel valve 548). In some embodiments, the parallel valve 548 can be actuated to selectively regulate the flow of fluid or to selectively adjust the pressure of the fluid in the gas cooler 329. The parallel valve 548 can selectively provide a portion of the fluid discharged by the gas cooler 329 to the expansion tank 413. In some examples, the parallel valve 548 can be actuated to open further to allow more fluid to flow from the gas cooler 329 to the flash tank 413, or the parallel valve 548 can be actuated to close further to allow less fluid to flow from the gas cooler 329 to the flash tank 413. The fluid expands as it flows through the parallel valve 548, and the pressure and / or temperature of the fluid may decrease. In some embodiments, the controller 380 can actuate the parallel valve 548 (e.g., open or close) based on sensor data received from one or more sensors.

[0067] In some embodiments, system 500A includes an auxiliary gas cooler 565 (e.g., an auxiliary condenser, an auxiliary heat exchanger, etc.), an auxiliary parallel valve 568, and / or an LP selector valve 563. In some embodiments, auxiliary gas cooler 565 receives the second fluid from the high-pressure outlet of PX 310. The auxiliary gas cooler 565 may be a condenser and / or a gas cooler as described herein. In some embodiments, auxiliary gas cooler 565 is a heat exchanger that exchanges thermal energy (e.g., heat) between the second fluid and the ambient environment. In some implementations, auxiliary gas cooler 565 exchanges thermal energy between the second fluid and the coolant of second cooling loop 370. In some embodiments, auxiliary gas cooler 565 operates at a different (e.g., lower) pressure than gas cooler 329. Because the second fluid (e.g., high pressure) discharged from PX 310 may be at a lower pressure than the pressure of gas cooler 329, an auxiliary gas cooler 565 operating at a lower pressure than gas cooler 329 can eliminate the need for a booster (e.g., HP booster 324) to compensate for this pressure difference.

[0068] In some embodiments, the second fluid flows from auxiliary gas cooler 565 to auxiliary parallel valve 568. In some embodiments, auxiliary parallel valve 568 is substantially similar to parallel valve 548. In some examples, auxiliary parallel valve 568 can be a flow control valve that controls the flow of the second fluid from auxiliary gas cooler 565 to flash tank 413. In some embodiments, auxiliary parallel valve 568 is an expansion valve. The second fluid can expand as the second fluid flows through auxiliary parallel valve 568. In some embodiments, auxiliary parallel valve 568 can be controlled (e.g., by controller 380). In some examples, controller 380 can cause auxiliary parallel valve 568 to be actuated (e.g., opened or closed) based on sensor data received from one or more sensors. The second fluid discharged from auxiliary parallel valve 568 can be combined with the fluid discharged from parallel valve 548 in some embodiments.

[0069] In some embodiments, the system 500A includes an LP selector valve 563. The LP selector valve 563 can receive gas discharged from the flash tank 413 via a first port and / or fluid discharged from the flash gas valve 420 and the evaporator 318 via a second port. The LP selector valve 563 can direct the gas flow and / or the liquid flow to the LP booster 314 via a third port. In some embodiments, the LP selector valve 563 is controllable. In some examples, a user (e.g., an engineer, technician, operator, etc.) can actuate the LP selector valve 563 (e.g., open or close the first, second, and / or third ports) and / or the controller 380 can actuate the LP selector valve 563. In some embodiments, the controller 380 actuates the LP selector valve 563 based on received sensor data. In some embodiments, the LP selector valve 563 receives a gas flow from the flash tank 413 through a first port and directs the gas flow toward the LP booster 314 through a third port while the second port is closed. In some embodiments, the LP selector valve 563 receives a fluid flow from the upstream side of the compressor 322 through a second port and directs the fluid flow toward the LP booster 314 through a third port while the first port is closed. In some embodiments, the LP selector valve 563 can allow intake of a flow from the suction side of the compressor 322 when there is not enough flash gas available in the flash tank 413. The LP selector valve 563 can be provided with fluid from the flash tank 413 and / or the suction side of the compressor 322 (e.g., the outlet side of the evaporator 318).

[0070] Referring to FIG. 5B, a schematic diagram of a data center cooling system 500B including a PX 310 is shown, according to certain embodiments. In some embodiments, features having similar reference numbers to those in other figures include similar properties, structures, and / or functions as those described in the other figures. In some examples, features of system 500B have similar properties, structures, and / or functions to systems 300A-300C of FIGS. 3A-3C, system 400 of FIG. 4, and system 500A of FIG. 5A. In some embodiments, system 500B may include any of server rooms 390A, 390B, and / or 390C, as shown in FIGS. 3A-3C.

[0071] In some embodiments, system 500B includes an air handling unit 599. Air handling unit 599 can receive the flow of warm air 398 and direct the warm air along the flow path of air loop 587 to evaporator 318. In some embodiments, the warm air is cooled (e.g., by a refrigerant) in evaporator 318. The cooled air can be provided to air handling unit 599. In some embodiments, a network of ducting directs air 398 between air handling unit 599 and evaporator 318. In some embodiments, air 398 is passed through a filter 595 in air handling unit 599. Filter 595 can be a particulate filter to filter contaminants from air 398. In some embodiments, fan 592 directs cool air from air handling unit 599 to server room 390B. In some embodiments, multiple fans are used to move air 398.

[0072] Referring to FIG. 5C, a schematic diagram of a data center cooling system 500C including a PX 310 is shown, according to certain embodiments. In some embodiments, features with similar reference numbers to those in other figures include similar properties, structures, and / or functions as those described in the other figures. In some examples, features of system 500C have similar properties, structures, and / or functions to systems 300A-300C of FIGS. 3A-3C, system 400 of FIG. 4, and systems 500A-500B of FIGS. 5A-5B. In some embodiments, system 500C may include any of server rooms 390A, 390B, and / or 390C, as shown in FIGS. 3A-3C.

[0073] In some embodiments, system 500C includes an auxiliary gas cooler 566 that receives the fluid discharged from the HP outlet of PX 310 (e.g., the second fluid at the fourth pressure). In some embodiments, heat is discharged from the HP outlet of PX 310 through the auxiliary gas cooler 566. In some embodiments, an auxiliary high-pressure valve 569 controls the flow of fluid through the auxiliary gas cooler 566, which in turn controls the flow of fluid discharged from the HP outlet of PX 310. In some embodiments, as the fluid loses heat in the auxiliary gas cooler 566, the temperature may decrease. The fluid may be combined with the fluid discharged from the LP outlet of PX 310 and provided to flash tank 413. In some embodiments, the inclusion of the auxiliary gas cooler 566 allows a high-pressure booster (e.g., high-pressure booster 324) to be eliminated from the system while maintaining the same functionality. Eliminating the high-pressure booster may result in reduced cost and maintenance (e.g., due to a reduced number of moving parts and / or components) and improved system reliability.

[0074] In some embodiments, the fluid exiting the gas cooler 329 passes through a subcooling heat exchanger 530. In some embodiments, the fluid is subcooled (e.g., cooled to a temperature below the saturation temperature) such that the fluid at least partially transitions to a liquid state. Upon exiting the subcooling heat exchanger 530, a first subportion of the fluid is provided to the HP inlet of the PX 310 (e.g., a first fluid at a first pressure). A second subportion of the fluid is provided to the subcooling heat exchanger 530 to cool the fluid flowing from the gas cooler 329. The second subportion of the fluid may pass through a bypass high-pressure valve 549. In some embodiments, the second subportion of the fluid expands and / or decreases in temperature as it flows through the bypass high-pressure valve 549. In some embodiments, the bypass high-pressure valve 549 is actuable. The actuation of the bypass high-pressure valve 549 may be controlled by the controller 380 (e.g., based on sensor data, etc.). A second subportion of the fluid may be provided to the LP inlet of PX 310 (e.g., a second fluid at a second pressure). In some embodiments, the inclusion of subcooling heat exchanger 530 may eliminate a low-pressure booster (e.g., low-pressure booster 314) from the system while maintaining the same functionality. Elimination of the low-pressure booster may lead to reduced power requirements, reduced maintenance (e.g., due to a reduced number of moving parts and / or components), and improved system reliability.

[0075] Referring to FIG. 5D , a schematic diagram of a data center cooling system 500D including a PX 310 is shown, according to certain embodiments. In some embodiments, features having similar reference numbers to those in other figures include similar properties, structures, and / or functions as those described in the other figures. In some examples, features of system 500D have similar properties, structures, and / or functions to systems 300A-300C of FIGS. 3A-3C , system 400 of FIG. 4 , and systems 500A-500C of FIGS. 5A-5C . In some embodiments, system 500D can include any of server rooms 390A, 390B, and / or 390C, as shown in FIGS. 3A-3C .

[0076] In some embodiments, system 500D includes auxiliary flash tank 514. Auxiliary flash tank 514 may be a receiver (e.g., a receiver tank, etc.) for receiving a fluid flow from gas cooler 329 and / or auxiliary gas cooler 565. Auxiliary flash tank 514 may receive a second fluid from a second outlet of PX 310 (e.g., via auxiliary gas cooler 565 and auxiliary parallel valve 568). In some embodiments, auxiliary flash tank 514 may maintain a pressure differential (e.g., a small pressure differential, such as 10 psi (approximately 68.95 kPa), 20 psi (approximately 137.90 kPa), 30 psi (approximately 206.84 kPa), 40 psi (approximately 275.79 kPa), 50 psi (approximately 344.74 kPa), etc.) between auxiliary flash tank 514 and primary flash tank 413. The pressure differential between the flash tanks may drive fluid flow through the low-pressure inlet port of PX 310 toward the low-pressure outlet port of PX 310, which may function as a low-pressure booster (e.g., low-pressure booster 314). Fluid from gas cooler 329 may pass through subcooling heat exchanger 530 and / or parallel valve 548 before entering auxiliary flash tank 514. In some embodiments, subcooling heat exchanger 530 exchanges heat between a portion of the fluid stream exiting gas cooler 329 and the fluid stream exiting the LP outlet of PX 310. In some embodiments, the fluid exiting the LP outlet of PX 310 is subcooled in subcooling heat exchanger 530. In some embodiments, the fluid exiting the LP outlet of PX 310 flows through a first low-pressure valve 517 downstream of subcooling heat exchanger 530. The first low-pressure valve 517 may be operable (e.g., by a technician, engineer, controller 380, etc.) to control the flow of fluid.

[0077] Fluid from the auxiliary gas cooler 565 may pass through an auxiliary parallel valve 568 before entering the auxiliary flash tank 514. In some embodiments, the fluid separates into gas and liquid in the auxiliary flash tank 514. The gas collected in the auxiliary flash tank 514 may be provided to the LP inlet of the PX 310 (e.g., a second fluid at a second pressure). The liquid collected in the auxiliary flash tank 514 may flow out of the auxiliary flash tank 514 and through a second low-pressure valve 519 into the flash tank 413. In some embodiments, the liquid is combined with the fluid discharged from the LP outlet of the PX 310 (e.g., a first fluid at a third pressure). The second low-pressure valve 519 may be operable (e.g., by a technician, engineer, controller 380, etc.) to control the flow of fluid. In some embodiments, the inclusion of the auxiliary flash tank 514 allows the low-pressure booster (e.g., low-pressure booster 314) to be eliminated from the system while maintaining the same functionality. Elimination of the low voltage booster can lead to reduced power demands, reduced maintenance (e.g., due to fewer moving parts and / or components), reduced costs, and increased reliability of the equipment. Decoupling of the low voltage booster can lead to reduced power demands, reduced maintenance (e.g., due to fewer moving parts and / or components), reduced costs, and increased reliability of the system.

[0078] Referring to FIG. 5E, a schematic diagram of a data center cooling system 500E including a PX 310 is shown, according to certain embodiments. In some embodiments, features having similar reference numbers to those in other figures include similar properties, structures, and / or functions as those described in the other figures. In some examples, features of system 500E have similar properties, structures, and / or functions as systems 300A-300C of FIGS. 3A-3C, system 400 of FIG. 4, and systems 500A-500D of FIGS. 5A-5D.

[0079] In some embodiments, the refrigeration system / cycle of system 500E may be substantially similar to that of system 500C. However, in some embodiments, system 500E includes a first cooling loop 386 and a CRAC 391 in a server room to cool air 398 for cooling servers in racks 399. In some embodiments, system 500E may include any of server rooms 390A, 390B, and / or 390C.

[0080] Referring to FIG. 5F, a schematic diagram of a data center cooling system 500F including a PX 310 is shown, according to certain embodiments. In some embodiments, features having similar reference numbers to those in other figures include similar properties, structures, and / or functions as those described in the other figures. In some examples, features of system 500F have similar properties, structures, and / or functions as systems 300A-300C of FIGS. 3A-3C, system 400 of FIG. 4, and systems 500A-500E of FIGS. 5A-5E.

[0081] In some embodiments, the refrigeration system / cycle of system 500F may be substantially similar to that of system 500D. However, in some embodiments, system 500F includes a first cooling loop 386 and CRAC 391 in a server room to cool air 398 for cooling servers in racks 399. In some embodiments, system 500E may include any of server rooms 390A, 390B, and / or 390C. In some embodiments, system 500F includes a second cooling loop 370 that rejects heat from the servers to the ambient environment via cooling towers 374.

[0082] FIG. 6 is a flow diagram illustrating a method 600 for controlling a data center cooling system (e.g., one or more of systems 300A-C of FIGS. 3A-3C) according to certain embodiments. In some embodiments, method 600 is performed by processing logic including hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, a processing device, etc.), software (e.g., instructions running on a processing device, a general-purpose computer system, or a dedicated machine, etc.), firmware, microcode, or a combination thereof. In some embodiments, method 600 is performed, at least in part, by a controller (e.g., controller 180 of FIGS. 1A-1B, controller 380 of FIGS. 3A-3C, etc.). In some embodiments, a non-transitory storage medium stores instructions that, when executed by a processing device (e.g., controller 180 of FIGS. 1A-1B, controller 380 of FIGS. 3A-3C, etc.), cause the processing device to perform method 600.

[0083] For simplicity of explanation, method 600 is depicted and described as a series of acts. However, acts in accordance with the present disclosure may occur in various orders and / or simultaneously, and with other acts not shown and described herein. Moreover, in some embodiments, not all illustrated acts are performed to implement method 600 in accordance with the disclosed subject matter. Additionally, those skilled in the art will understand and appreciate that method 600 could alternatively be represented as a series of interrelated states via a state diagram or events.

[0084] At block 602, processing logic causes heat to be exchanged between a first cooling loop and a refrigeration system via a first heat exchanger (e.g., evaporator 318). In some embodiments, the first cooling loop is a data center cooling loop for cooling servers in a server room.

[0085] At block 604, processing logic causes a plurality of servers in a data center to be cooled via a first cooling loop (e.g., cooling loop 386). In some embodiments, the first cooling loop is configured to provide a chilled coolant (e.g., water, a water-glycol mixture, etc.) to a CRAC (e.g., CRAC 391) in a server room. The CRAC can cool air circulating in the server room. The cooling coils of the CRAC can cool the air in the server room to cool the servers. The servers can warm the air in the server room, and the warmed air can be routed to the CRAC. Heat from the servers can be provided to the first cooling loop (e.g., via the cooling coils of the CRAC). Heat from the servers can be exchanged between the first cooling loop and a refrigeration system (e.g., at block 602).

[0086] At block 606, processing logic causes a pressure exchange between a first fluid of the refrigeration system and a second fluid of the refrigeration system via a pressure exchanger (e.g., PX 310). In some examples, processing logic (e.g., of controller 380) may operate the pressure exchanger to exchange pressure between the first fluid and the second fluid. Specifically, processing logic may cause one or more valves to open and one or more pumps and / or compressors to provide the first fluid and the second fluid to an inlet of the pressure exchanger. Processing logic may cause a compressor and / or a booster (e.g., LP booster 314) to flow the first fluid and the second fluid (respectively) to the pressure exchanger based on sensor data (e.g., temperature sensor data, pressure sensor data, flow sensor data, etc.). The first fluid may be provided to a first inlet of the pressure exchanger at a first pressure, and the second fluid may be provided to a second inlet of the pressure exchanger at a second pressure. The first pressure may be higher than the second pressure. In some embodiments (e.g., embodiments in which the pressure exchanger is a rotary pressure exchanger), the processing logic may cause a motor to rotate a rotor of the pressure exchanger. Pressure may be exchanged between the first and second fluids by providing the first and second fluids to an inlet of the pressure exchanger via a compressor and / or a booster and / or by rotating the rotor of the pressure exchanger via a motor. The first fluid may exit the pressure exchanger through the first outlet at a third pressure, and the second fluid may exit the pressure exchanger through the second outlet at a fourth pressure. The third pressure may be lower than the fourth pressure.

[0087] At block 608, processing logic causes heat to be exchanged between the refrigeration system and a second cooling loop (e.g., cooling loop 370) via a second heat exchanger (e.g., gas cooler 329). In some embodiments, the refrigeration system provides heat (e.g., heat from the servers cooled at block 604) from the first heat exchanger to the second heat exchanger.

[0088] At block 610, processing logic causes rejection of heat from the second cooling loop to the ambient environment via a cooling tower (e.g., cooling tower 374). In some embodiments, the cooling tower receives the coolant of the second cooling loop and cools the coolant by rejecting heat to the ambient environment. The ambient environment may be an environment external to the refrigeration system and / or external to the data center. In some embodiments, a chiller unit is used to reject heat to the ambient environment.

[0089] 7 is a block diagram illustrating a computer system 700 according to certain embodiments. In some embodiments, computer system 700 is a client device. In some embodiments, computer system 700 is a controller device (e.g., a server, controller 180 of FIGS. 1A-1B, controller 380 of FIGS. 3A-3C, 4, and 5A-5F).

[0090] In some embodiments, computer system 700 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 700 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 700 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 collectively execute a set(s) of instructions to perform any one or more of the methods described herein.

[0091] In some embodiments, computer system 700 includes a processing device 702, volatile memory 704 (e.g., random access memory (RAM)), non-volatile memory 706 (e.g., read-only memory (ROM) or electrically erasable programmable ROM (EEPROM)), and / or data storage device 716, which communicate with each other via a bus 708.

[0092] In some embodiments, processing device 702 is provided by one or more processors, such as a general-purpose processor (in some examples, 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 microprocessor implementing combined types of instruction sets) or a specialized processor (e.g., in some examples, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a digital signal processor (DSP), or a network processor, etc.). In some embodiments, processing device 702 is provided by one or more of a single processor, multiple processors, a single processor with multiple processing cores, and / or the like.

[0093] In some embodiments, computer system 700 further includes a network interface device 722 (e.g., coupled to a network 774). In some embodiments, computer system 700 includes one or more input / output (I / O) devices. In some embodiments, computer system 700 also includes a video display unit 710 (e.g., a liquid crystal display (LCD)), an alphanumeric input device 712 (e.g., a keyboard), a cursor control device 714 (e.g., a mouse), and / or a signal generating device 720.

[0094] In some implementations, a data storage device 718 (e.g., disk drive storage, fixed and / or removable storage devices, fixed disk drives, removable memory cards, optical storage, network attached storage (NAS), and / or storage area networks (SANs)) includes a non-transitory computer-readable storage medium 724 that stores instructions 726 that encode any one or more of the methods or functions described herein to implement the methods described herein.

[0095] In some embodiments, the instructions 726 also reside, completely or partially, within the volatile memory 704 and / or within the processing device 702 during execution by the computer system 700; and thus, in some embodiments, the volatile memory 704 and the processing device 702 also constitute machine-readable storage media.

[0096] Although the computer-readable storage medium 724 is shown as a single medium in the illustrated 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.

[0097] 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.

[0098] Unless otherwise specified, terms such as "operate," "regulate," "cause," "control," "determine," "identify," "provide," "receive," "adjust," 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.

[0099] 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.

[0100] 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.

[0101] The above 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. As such, the specific details described are merely exemplary. Particular implementations may vary from these example details and still be contemplated as being within the scope of the present disclosure.

[0102] 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 the terms "about," "substantially," or "approximately" are used herein, this is intended to mean that the stated nominal value is accurate to within ±10%. Additionally, the terms "first," "second," "third," "fourth," etc., when used herein, are intended as labels to distinguish between different elements and do not necessarily have an ordinal meaning according to their numerical designations.

[0103] As used herein, the terms "above," "below," "between," "disposed on," and "on" refer to the relative position of one material layer or component with respect to another layer or component. In some instances, 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.

[0104] Although the method operations herein are shown and described in a particular order, the order of each method operation may be changed such that certain operations may be performed in reverse order or such that certain operations may be performed at least partially concurrently with other operations. In other embodiments, the order of separate operations or sub-operations may be intermittent and / or alternating. In one embodiment, the operation of joining multiple metals is performed as a single step.

[0105] It should be understood that the above description is illustrative, and not limiting. Many other embodiments will be 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 system comprising: a refrigeration system exchanging heat between a first cooling loop and a second cooling loop, the first cooling loop configured to cool a plurality of servers in a data center, the second cooling loop configured to provide heat to a cooling tower and reject the heat to an ambient environment, and the refrigeration system: a pressure exchanger (PX) configured to receive a first fluid at a first pressure through a first inlet of the PX and a second fluid at a second pressure through a second inlet of the PX and to exchange pressure between the first fluid and the second fluid, the first fluid exiting the PX at a third pressure through a first outlet of the PX and the second fluid exiting the PX at a fourth pressure through a second outlet of the PX; the refrigeration system further comprising: a first heat exchanger configured to exchange first heat between the first cooling loop and at least a portion of the first fluid discharged from the first outlet of the PX; a second heat exchanger configured to exchange second heat between at least a portion of the first fluid entering the first inlet of the PX and the second cooling loop.

2. 2. The system of claim 1, wherein the first heat exchanger comprises an evaporator of the refrigeration system configured to transition the at least a portion of the first fluid discharged from the first outlet of the PX from a liquid state to a vapor state.

3. The system of claim 1 , wherein the second heat exchanger comprises a gas cooler of the refrigeration system configured to cool the at least a portion of the first fluid.

4. The first fluid and the second fluid are carbon dioxide (CO ２ 2. The system of claim 1, wherein the first pressure is greater than the second pressure and the third pressure is less than the fourth pressure.

5. The refrigeration system comprises:

2. The system of claim 1, further comprising an auxiliary heat exchanger configured to receive the second fluid discharged from the second outlet of the PX and exchange third heat from the second fluid with the ambient environment.

6. The refrigeration system comprises: The system of claim 5 , further comprising a valve configured to receive the second fluid from the auxiliary heat exchanger and regulate the flow of the second fluid toward a receiver.

7. The refrigeration system comprises:

2. The system of claim 1, further comprising a third heat exchanger configured to exchange a third heat between at least the portion of the first fluid entering the first inlet of the PX and a sub-portion of the fluid discharged from the third heat exchanger, and to sub-cool the at least the portion of the first fluid entering the first inlet of the PX.

8. The refrigeration system comprises: Further comprising a booster, the booster comprising: receiving the second fluid at the fourth pressure discharged from the PX; increasing the pressure of the second fluid; and The system of claim 7 configured to provide the second fluid upstream of an inlet of the second heat exchanger.

9. The refrigeration system comprises:

10. The system of claim 1, further comprising a first receiver configured to receive the first fluid from the first outlet of the PX, the receiver forming a chamber configured to separate the first fluid into a first gas and a first liquid.

10. The refrigeration system comprises: Further comprising a booster, the booster comprising: receiving a portion of the first gas from the first receiver; increasing the pressure of the portion of the first gas to form the second fluid at the second pressure; and The system of claim 9 configured to provide the second fluid at the second pressure to the PX via the second inlet.

11. The refrigeration system comprises:

9. The system of claim 8, further comprising a second receiver configured to receive the second fluid discharged from the second outlet of the PX and to provide at least a portion of the second fluid discharged from the second outlet of the PX to the second inlet of the PX as the second fluid at the second pressure.

12. The refrigeration system comprises:

10. The system of claim 1, further comprising a compressor configured to receive at least a portion of the first fluid discharged from the first heat exchanger, increase a corresponding pressure of the at least a portion of the first fluid, and provide the at least a portion of the first fluid to the second heat exchanger.

13. The system comprises:

10. The system of claim 1, further comprising: a cooler unit configured to perform a third heat exchange between the first cooling loop and air circulating within the data center to cool the plurality of servers.

14. The system comprises:

14. The system of claim 13, further comprising a pump configured to pump coolant along the first cooling loop between the first heat exchanger and the cooler unit.

15. 14. The system of claim 13, wherein the cooler unit comprises a cooling coil configured to receive coolant from the first heat exchanger along the first cooling loop and to exchange heat between the air in the data center and the coolant.

16. 14. The system of claim 13, wherein the data center comprises a raised floor configured to support a plurality of server racks for supporting the plurality of servers, and wherein the air flows through the raised floor to the plurality of server racks.

17. 14. The system of claim 13, wherein the data center comprises ducting configured to direct heated air away from the plurality of servers and toward the cooler unit.

18. 1. A system comprising: a refrigeration system configured to cool a plurality of servers in a data center, the refrigeration system comprising: a pressure exchanger (PX) configured to receive a first fluid at a first pressure through a first inlet of the PX and a second fluid at a second pressure through a second inlet of the PX and to exchange pressure between the first fluid and the second fluid, the first fluid exiting the PX at a third pressure through a first outlet of the PX and the second fluid exiting the PX at a fourth pressure through a second outlet of the PX; a first heat exchanger configured to provide first heat from the plurality of servers to at least a portion of the first fluid discharged from the first outlet of the PX; a second heat exchanger configured to provide second heat from at least a portion of the first fluid entering the first inlet of the PX to a cold sink.

19. The first fluid and the second fluid are carbon dioxide (CO ２ 20. The system of claim 18, wherein the first pressure is greater than the second pressure and the third pressure is less than the fourth pressure.

20. 20. The system of claim 18, wherein the first heat exchanger is configured to cool air circulating within the data center.

21. The refrigeration system comprises: The refrigeration system further comprises a receiver configured to receive the first fluid from the first outlet of the PX, the receiver forming a chamber configured to separate the first fluid into a first gas and a first liquid, a booster, the booster comprising: receiving a portion of the first gas from the receiver; increasing the pressure of the portion of the first gas to form the second fluid at the second pressure; and 20. The system of claim 18, configured to provide the second fluid at the second pressure to the PX via the second inlet.

22. The refrigeration system comprises:

20. The system of claim 18, further comprising a compressor configured to receive at least a portion of the first fluid discharged from the second heat exchanger, increase a corresponding pressure of the at least a portion of the first fluid, and provide the at least a portion of the first fluid to the first heat exchanger, the first heat exchanger configured to provide the first fluid to the PX via the first inlet.

23. 1. A system comprising: a refrigeration system configured to cool a plurality of servers, the refrigeration system comprising: a pressure exchanger (PX) configured to receive a first refrigeration fluid at a first pressure through a first inlet of the PX and a second refrigeration fluid at a second pressure through a second inlet of the PX and to exchange pressure between the first refrigeration fluid and the second refrigeration fluid, the first refrigeration fluid exiting the PX at a third pressure through a first outlet of the PX and the second refrigeration fluid exiting the PX at a fourth pressure through a second outlet of the PX; the refrigeration system further comprising: a first heat exchanger configured to provide first heat from the plurality of servers to at least a portion of the first refrigeration fluid discharged from the first outlet of the PX; a second heat exchanger configured to remove second heat from at least a portion of the first refrigeration fluid entering the first inlet of the PX.

24. 24. The system of claim 23, wherein the first pressure is greater than the second pressure and the third pressure is less than the fourth pressure.

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