Thermal energy storage system including a pressure exchanger

Abstract

The system includes a pressure exchanger (PX) configured to receive a first fluid at a first pressure and a second fluid at a second pressure and exchange pressure between the first and second fluids. The system further includes a first heat exchanger and a second heat exchanger. The system further includes a compressor. The system further includes an electrical energy generating device. The system further includes a first valve. The system further includes a processing device operably coupled to the first valve. The processing device is configured to provide a control signal to the first valve to cause the system to operate in a first mode or a second mode.

Description

[Technical Field]

[0001] The present disclosure relates to energy storage systems, and more particularly to thermal energy storage systems that include pressure exchangers.

[0002] The system uses fluids at different pressures. The system uses pumps or compressors to increase the pressure of the fluid. The system can use pressure changes in the working fluid to transfer energy between various components of the system.

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

[0004] [Figure 1A] FIG. 1A is a schematic diagram of a fluid treatment system including a hydraulic energy transfer system and a thermal energy storage medium, according to some embodiments. [Figure 1B] FIG. 1B is a schematic diagram of a fluid treatment system including a hydraulic energy transfer system and a thermal energy storage medium, according to some embodiments. [Figure 2A] FIG. 2A is an exploded perspective view of a pressure exchanger (PX), according to some embodiments. [Figure 2B] FIG. 2B is an exploded perspective view of a pressure exchanger (PX), according to some embodiments. [Figure 2C] FIG. 2C is an exploded perspective view of a pressure exchanger (PX), according to some embodiments. [Figure 2D] FIG. 2D is an exploded perspective view of a pressure exchanger (PX), according to some embodiments. [Figure 2E] FIG. 2E is an exploded perspective view of a pressure exchanger (PX), according to some embodiments. [Figure 3A] FIG. 3A is a schematic diagram of a thermal energy storage system including a PX, according to some embodiments. [Figure 3B]FIG. 3B is a schematic diagram of a thermal energy storage system including a PX, according to some embodiments. [Figure 3C] FIG. 3C illustrates a thermal energy storage system for generating a heat sink for cooling a target environment, according to some embodiments. [Figure 4A] FIG. 4A illustrates an example of a thermal energy storage medium management system, according to some embodiments. [Figure 4B] FIG. 4B illustrates a thermal energy storage medium reservoir, according to some embodiments. [Figure 4C] FIG. 4C illustrates a thermal energy gradient storage system, according to some embodiments. [Figure 4D] FIG. 4D illustrates a thermal energy storage medium system including a secondary energy transfer fluid, according to some embodiments. [Figure 5] FIG. 5 is a flow diagram of a method for operating a thermal energy storage system in a target mode, according to some embodiments. [Figure 6] FIG. 6 is a flow diagram of a method for operating a thermal energy storage system in a target mode, according to some embodiments. [Figure 7] FIG. 7 is a block diagram illustrating a computer system in accordance with certain embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0005] SUMMARY OF THE INVENTION Embodiments described herein relate to thermal energy storage systems that include pressure exchangers (eg, fluid processing systems, heat transfer systems, pressure exchanger systems, carbon dioxide (CO2) refrigeration systems, etc.).

[0006] Energy-utilizing operations may be inflexible in terms of when and how they rely on energy supplies. For example, operations in commercial environments may operate during traditional business hours, which may not coincide with times when energy is abundant (e.g., due to wind or sun, low energy costs, etc.). Such operations may include systems that can use fluids at different pressures. These systems may include hydraulic fracturing (e.g., fracking or fracing) systems, desalination systems, refrigeration systems, heat pump systems, energy generation systems, mud pump systems, slurry pump systems, industrial fluid systems, waste systems, fluid transport systems, thermal energy storage systems, etc. Pumps or compressors may be used to increase the pressure of fluids used by the systems.

[0007] Traditionally, refrigeration systems use pumps or compressors to increase the pressure of a fluid (e.g., a refrigerating fluid such as CO2, R-744, R-134a, hydrocarbons, hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), ammonia (NH3), refrigerant mixtures, R-407A, or R-404A). Traditionally, a separate pump or compressor mechanically coupled to a motor is used to increase the fluid pressure. 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 fluid pressure (via a pump or compressor driven by a motor). In addition, traditional heat pump systems (e.g., systems that transfer heat from one component to another via a working fluid) reduce the fluid pressure through an expansion valve. This process is one of the main reasons for the energy inefficiency of traditional heat pump systems because no useful work is extracted during the expansion process through the valve. Furthermore, hydrofluorocarbon (HFC) refrigerants (e.g., R-134a, R-404a, etc.) that may be used in such systems contribute to global warming and have been phased out by some countries and replaced with other refrigerants, such as CO2, that have reduced environmental impacts. However, the gas cooler / condenser pressure required for CO2-based heat pump systems is much higher than that required for commonly used HFC-based heat pump systems. Therefore, while CO2 systems are more climate-friendly, they consume much more energy than their HFC counterparts. The energy consumption of CO2 systems increases further when the systems are operated at warmer gas cooler outlet temperatures (i.e., higher load return temperatures) because as the gas cooler outlet temperature increases, the gas cooler / condenser pressure increases, and therefore the compressor must do more work. This is one of the major challenges associated with CO2 heat pump systems.Such a limitation may be the energy used to operate a conventional system (e.g., the energy used to repeatedly increase the pressure of a working fluid to cause an increase or decrease in the temperature of the surrounding environment).

[0008] The disclosed systems, devices, and methods provide thermal energy storage systems. The disclosed systems, devices, and methods provide fluid processing systems (e.g., for thermal energy storage, for heat transfer systems). Thermal energy storage systems can operate to transfer heat from one medium to another so that the medium can later be utilized to perform a target function. In some embodiments, thermal energy is stored in a medium by utilizing a heat pump architecture. The heat pump architecture extracts heat from a lower temperature heat source and stores the thermal energy in a higher temperature heat sink. The stored thermal energy can later be utilized to generate electricity, for example, via a heat engine architecture. In some embodiments, thermal energy is extracted from a low temperature heat sink, which is later used to absorb unwanted heat, such as in a refrigeration or air conditioning system. In some embodiments, fairly low temperature waste heat (e.g., low-grade waste heat from an industrial process) can be transferred to a high temperature thermal energy storage medium via a heat pump architecture. The high temperature thermal energy storage medium can be utilized to provide useful heat (eg, high grade, high temperature heat) for industrial or other processes, or at a later time as residential heat.

[0009] A thermal energy storage system may include the ability to perform charge and discharge cycle operations. The charge cycle may allow for the storage of energy and / or the creation of a thermal energy storage medium at a temperature state that can be subsequently utilized during the discharge cycle to perform work, generate electricity, perform industrial or other useful functions, etc. In some embodiments, the charge cycle operation may be performed in response to some target condition of the thermal energy storage system. In some embodiments, the discharge cycle operation may be performed in response to a second target condition of the thermal energy storage system. For example, the charge cycle operation may be performed when renewable energy (e.g., solar, wind) is available, and the discharge cycle operation may be performed when such energy sources are unavailable. The charge cycle operation may be performed when energy costs are low, and the discharge cycle operation may be performed when energy costs are high. The charge cycle operation may be performed to upgrade low-grade waste heat to usable heat for industrial processes while low-grade waste heat is available. A corresponding discharge cycle operation may be performed while waste heat is unavailable.

[0010] In some embodiments, a system (e.g., a fluid processing system, a thermal energy transfer system, a refrigeration system, a heat pump system, a heat transfer system, a CO2 refrigeration system, etc.) includes a pressure exchanger (PX) configured to exchange pressure between a first fluid (e.g., a high-pressure portion of a refrigeration fluid in a refrigeration cycle) and a second fluid (e.g., a low-pressure portion of a refrigeration fluid in a refrigeration cycle). In some embodiments, the PX can receive the first fluid (e.g., a portion of the high-pressure refrigeration fluid) through a first inlet (e.g., a high-pressure inlet) and the second fluid (e.g., a portion of the low-pressure refrigeration fluid) through a second inlet (e.g., a low-pressure inlet). Upon entering the PX, the first fluid can have a higher pressure than the second fluid. The PX can exchange pressure between the first fluid and the second fluid. The first fluid can exit the PX through a first outlet (e.g., a low-pressure outlet), and the second fluid can exit the PX through a second outlet (e.g., a high-pressure outlet). Upon exiting the PX, the second fluid may have a higher pressure than the first fluid (e.g., due to pressure exchange between the first and second fluids). Aspects of the present disclosure solve the challenge of utilizing CO2 for thermal energy storage by extracting energy during the expansion of the high-pressure refrigerant CO2 and using it to compress a portion of the refrigerant stream, thereby reducing the energy consumption of the heat pump system's main compressor. This makes the charge cycle of the thermal energy storage system more efficient.

[0011] In some embodiments, one or more of the heat sink and / or heat source may be in an environment proximate to a portion of the fluid treatment system, such as an environment proximate to a heat exchanger. In some embodiments, the system further includes one or more thermal energy storage media. For example, a first portion of the fluid treatment system may place the working fluid in thermal communication with a first thermal energy storage medium, and a second portion of the fluid treatment system may place the working fluid in thermal communication with a second thermal energy storage medium. In some embodiments, thermal energy may be stored (e.g., transferred from a “cold” thermal medium to a “hot” thermal medium for storage) during a charge cycle operation, and the thermal energy may be utilized by the system to perform a useful function during a discharge cycle. In some examples, the thermal energy storage device may store cold, e.g., remove thermal energy from the storage medium during a charge cycle, and provide heat to the storage medium during a discharge cycle (e.g., for a refrigeration or air conditioning system). The thermal energy storage medium may include molten salt, dry ice, water, water and ice slurry, glycol, glycol / water mixture, phase change material (e.g., paraffin such as octadecane, salt hydrate, fatty acid, ester, ionic liquid, gel, polymer, etc.), eutectic material (e.g., a mixture of materials with a lower melting point than other compositions of the same material), molten metal (e.g., aluminum), molten silicon, sand, rock, brick, or stone, or other medium. In some embodiments, the thermal energy storage medium may be pumped, conveyed, etc., through a heat exchanger in thermal communication with the working fluid. In some embodiments, a secondary fluid may be in thermal communication with both the primary working fluid and the thermal energy storage medium. In some embodiments, the heat exchanger in thermal communication with the working fluid may be embedded within a reservoir comprising the thermal energy storage medium.

[0012] In some embodiments, the system further includes a heat exchanger (e.g., a condenser, a condensing unit (CU), a gas cooler, an air conditioning condenser, etc.) configured to provide a first fluid to the PX (e.g., via a first inlet of the PX) and transfer corresponding thermal energy (e.g., heat) between the first fluid and a corresponding environment (e.g., a heat sink, a high-temperature reservoir, a high-temperature thermal energy storage medium, a heat source, a low-temperature reservoir, ambient air, the ground, etc.). In some embodiments, the first fluid (e.g., a high-pressure fluid) loses heat to the environment and condenses in the heat exchanger. An output of the heat exchanger (e.g., a portion of the heat exchanger output, the first fluid, etc.) may be provided to a high-pressure inlet of the PX. The heat exchanger may be upstream of the PX in the flow path of the first fluid. In some embodiments, the system further includes a second heat exchanger (e.g., an evaporator) configured to transfer heat from the heat source to the working fluid of the system. The input of the evaporator may be coupled to the outlet of the PX.

[0013] In some embodiments, the system further includes a receiver (e.g., a flash tank) that receives the first fluid discharged from the low-pressure outlet of the PX. The receiver can form a chamber in which the low-pressure first fluid gas and liquid can separate. The booster can receive gas (e.g., the high-pressure first fluid gas) from the receiver and increase the pressure of the gas to form a second fluid.

[0014] In some embodiments, the system further includes a booster configured to receive gas (e.g., a low-pressure first fluid gas) from the receiver, increase the pressure of the gas (e.g., a first portion of the first gas) to form a second fluid (e.g., a portion of the low-pressure refrigeration fluid) at a second pressure, and provide the second fluid at the second pressure to the PX via the second inlet. The booster may be a pump or a compressor and may increase the pressure of the second fluid across a fairly small pressure differential. Further details regarding the pressure differential of the booster are described herein. The booster may provide the second fluid at the second pressure to a low-pressure inlet (e.g., the second inlet) of the PX.

[0015] The system may further include one or more of an expansion valve and a compressor to perform a refrigeration cycle, a heat transfer cycle, a heat pump cycle, a heat engine cycle, etc. The working fluid may expand through the expansion valve to reduce its pressure and temperature. The working fluid may receive thermal energy (e.g., heat) from another environment (e.g., a heat source, a cold reservoir, etc.) through another heat exchanger (e.g., an evaporator). The working fluid may be compressed in a compressor to increase the pressure of the refrigeration fluid. Thermal energy may be rejected from the working fluid in a condenser, and a first fluid (e.g., at least a portion of the working fluid) may enter the PX and exchange pressure with a second fluid as part of a heat transfer cycle.

[0016] The systems, devices, and methods of the present disclosure have advantages over conventional solutions. The systems of the present disclosure may use a reduced amount of energy compared to conventional systems (e.g., using reduced energy to run a heat pump). The PX can allow for the recovery of energy (e.g., pressure) that is typically lost in conventional systems. This makes the systems of the present disclosure more efficient, and therefore uses less energy and costs less over time to end users compared to conventional solutions. The systems of the present disclosure allow for the storage of thermal energy that is separated in time from the utilization of the stored energy. The separation in time of energy storage and energy utilization can allow for the use of energy availability to perform operations during times of energy shortage. Storing thermal energy for later use can reduce the cost of operating the system and reduce the environmental impact of operating the 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 ejectors instead of boosters). 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.

[0017] 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.).

[0018] Although some embodiments of the present disclosure are described in connection with exchanging pressure between fluids used in 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.

[0019] In some aspects of the present disclosure, a system includes a pressure exchanger (PX) configured to receive a first fluid at a first pressure and a second fluid at a second pressure and exchange pressure between the first and second fluids. The system further includes a first heat exchanger and a second heat exchanger. The system further includes a compressor. The system further includes an electrical energy generating device. The system further includes a first valve. The system further includes a processing device operably coupled to the first valve. The processing device is configured to provide a control signal to the first valve to operate the system in a first mode or a second mode. Operation in the first mode includes providing a fluid flow to the PX, the first heat exchanger, the second heat exchanger, and the compressor. Operation in the second mode includes providing a fluid flow to the first heat exchanger, the second heat exchanger, and the electrical energy generating device.

[0020] In another aspect of the present disclosure, a system includes a PX configured to receive a first fluid, receive a second fluid, and exchange pressure between the first and second fluids. The system further includes a heat exchanger configured to receive the first fluid from the PX and exchange heat between the first fluid and a third fluid. The system further includes a thermal storage medium in thermal communication with the third fluid. The system further includes a cooling coil configured to exchange thermal energy between the third fluid and an environment proximate to the cooling coil. The system further includes a pump configured to circulate the third fluid between the thermal storage medium, the cooling coil, and the heat exchanger.

[0021] In another aspect of the present disclosure, a system includes a PX configured to receive a first fluid, receive a second fluid, and exchange pressure between the first and second fluids. The system further includes a first heat exchanger configured to provide the first fluid to the PX. The first heat exchanger is in thermal communication with a thermal storage medium. The system further includes a second heat exchanger configured to receive the first fluid from the PX. The second heat exchanger is in thermal communication with a heat source. The system further includes a heat sink in thermal communication with the thermal storage medium. The system further includes a processing device configured to provide a control signal to operate the system in a first mode or a second mode.

[0022] FIG. 1A shows a schematic diagram of a fluid treatment system 100A including a hydraulic energy transfer system 110 and a thermal energy storage medium 180, according to certain embodiments.

[0023] In some embodiments, hydraulic energy transfer system 110 includes a pressure exchanger (e.g., PX). Hydraulic energy transfer system 110 (e.g., PX) receives low-pressure (LP) in fluid 120 from LP in system 122 (e.g., via a low-pressure inlet). Hydraulic energy transfer system 110 also receives high-pressure (HP) in fluid 130 from HP in system 132 (e.g., via a high-pressure inlet). Hydraulic energy transfer system 110 (e.g., PX) exchanges pressure between HP in fluid 130 and LP in fluid 120 to provide LP out fluid 140 to LP out system 142 (e.g., via a low-pressure outlet) and HP out fluid 150 to HP out system 152 (e.g., via a high-pressure outlet). A controller can cause regulation of the flow rates of HP in fluid 130 and LP out fluid 140 by one or more flow valves, pumps, and / or compressors (not shown). Fluid treatment system 100A includes one or more thermal energy storage media 180. Thermal energy storage media 180 may provide a heat sink, e.g., a material utilized by fluid treatment system 100A to absorb and retain heat. Thermal energy storage media 180 may provide a heat source, e.g., a material utilized by fluid treatment system 100A to provide heat and maintain a low temperature for later absorbing heat.

[0024] 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 of the PX may be pressurized and exit the PX at a high pressure (e.g., HPout fluid 150, at a pressure higher than that 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 that of the HPin fluid 130). The PX may operate such that the HPin fluid 130 applies a force directly to the LPin fluid 120, pressurizing it, 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, a rotary PX operates using internal pistons to isolate fluids and transfer pressure with significantly less mixing of the inlet fluid streams. In some embodiments, a rotary PX operates without an internal piston between the fluids. A reciprocating PX can include a piston that moves back and forth within a cylinder to transfer pressure between the fluid streams. Any one or more PXs, for example, but not limited to, a rotary PX, a reciprocating PX, or any combination thereof, can 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., system pipes) that is constructed on-site. The structure to which the PX is fixed is sometimes referred to as a "skid."

[0025] In some embodiments, a motor 160 is coupled to the hydraulic energy transmission system 110 (e.g., to PX). In some embodiments, the motor 160 controls the speed of a rotor of the hydraulic energy transmission system 110 (e.g., to increase the pressure of the HPout fluid 150, or to decrease the pressure of the HPout fluid 150). In some embodiments, the motor 160 generates energy (e.g., acts as a generator) based on pressure exchanges within the hydraulic energy transmission system 110.

[0026] 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 to 100) to facilitate pressure transfer between a first fluid and a second fluid (e.g., gas, liquid, multiphase fluid). In some embodiments, the PX may transfer pressure between a first fluid (e.g., a pressure exchange fluid, such as a proppant-free fluid, a substantially proppant-free fluid, a high-density fluid, a low-viscosity fluid, a fluid having less than a threshold amount of a particular chemical), and a second fluid that may have a higher viscosity (e.g., high viscosity), a lower density, may have more than a threshold amount of a particular chemical, and / or may contain solid particles (e.g., fracking fluid, and / or a fluid containing sand, proppant, powder, debris, ceramic, contaminants, particles from welds or solder joints, etc.).

[0027] In some embodiments, the L-pin system 122 includes a booster (e.g., a pump and / or a compressor) to increase the pressure of the fluid to form the L-pin fluid 120. In some embodiments, the L-pin system 122 includes an ejector to increase the pressure of the fluid to form the L-pin fluid 120. In some embodiments, the L-pin system 122 receives gas from the L-pin system 142. In some embodiments, the L-pin system 122 receives fluid from a receiver (e.g., a flash tank). The receiver may receive the L-pin fluid 140 discharged from the hydraulic energy transfer system 110.

[0028] Fluid treatment 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 treatment system 100A. One or more controllers may control one or more flow rates in fluid treatment system 100A based on the sensor data. In some embodiments, the controller actuates one or more flow valves based on the received sensor data.

[0029] One or more components of the hydraulic energy transfer system 110 may be used in various types of systems, such as thermal energy storage systems, milling systems, desalination systems, refrigeration and heat pump systems (e.g., FIG. 1B), slurry pump systems, industrial fluid systems, waste systems, fluid transport systems, heat transfer systems, etc.

[0030] FIG. 1B shows a schematic diagram of a fluid treatment system 100B including a hydraulic energy transfer system 110 and a thermal energy storage medium 180, according to certain embodiments. Fluid treatment system 100B may be a thermal energy storage system, a refrigeration system, and / or a heat pump system. In some embodiments, fluid treatment system 100B is a thermal energy (e.g., heat) transport system (e.g., thermal, heat transport system). Fluid treatment system 100B may be configured to store thermal energy for later use. Fluid treatment system 100B may be configured to upgrade thermal energy from low-grade (e.g., low-temperature) to high-grade (e.g., high-temperature) heat. Fluid treatment system 100B may be configured to maintain one or more thermal energy storage media at a temperature different from an ambient temperature, an equilibrium temperature, etc., and to use the stored media at a later time to perform one or more functions. Fluid treatment system 100B may be configured to cool and / or heat an environment (e.g., an indoor space, a refrigeration unit, a freezer, etc.). In some embodiments, fluid treatment system 100B includes more components, fewer components, the same routing, different routing, and / or the like than those shown in Figure 1B. Some of the features in Figure 1B that have similar reference numbers to Figure 1A may have similar properties, functions, and / or structures as Figure 1A.

[0031] The hydraulic energy transfer system 110 (e.g., PX) can receive an LPin fluid 120 from an LPin system 122 (e.g., a low-pressure lift device 128, a low-pressure fluid pump, a low-pressure booster, a low-pressure compressor, a low-pressure ejector, etc.) and an HPin fluid 130 from an HPin system 132 (e.g., a first heat exchanger (HX) 138, a condenser, a gas cooler, a heat exchanger, etc.). The first heat exchanger 138 can be in thermal communication with a thermal energy storage medium 180A. The first heat exchanger 138 can be embedded within the thermal energy storage medium 180A and can be in thermal contact with a secondary fluid to provide heat transfer, such as between the first heat exchanger 138 and the thermal energy storage medium 180A. Various fluid treatment systems, such as fluid treatment system 100B, may include one or more thermal energy storage media, such as thermal energy storage medium 180A coupled to first heat exchanger 138 and thermal energy storage medium 180B coupled to second heat exchanger 144. Hydraulic energy transfer system 110 (e.g., PX) may exchange pressure between LPin fluid 120 and HPin fluid 130 to provide HPout fluid 150 to HPout system 152 (e.g., high-pressure lift device 159, high-pressure fluid pump, high-pressure booster, high-pressure compressor, high-pressure ejector, etc.) and provide LPout fluid 140 to LPout system 142 (e.g., evaporator, second heat exchanger 144, heat exchanger, receiver 113, etc.). LPout system 142 (e.g., second heat exchanger 144, receiver 113) may provide fluid to compressor 178 and low-pressure lift device 128. The second heat exchanger 144 can provide fluid to the compressor 178, and the receiver 113 (e.g., a flash tank) can provide fluid to the low-pressure lift device 128. The receiver 113 can form a chamber for collecting and / or containing fluid. The receiver 113 can receive fluid in a two-phase state (e.g., liquid and gas). The receiver 113 can separate the phases of the fluid. The receiver 113 can allow gas and liquid to be provided separately to other components, for example, to control fluid density or to ensure that a target phase reaches a target component. The first heat exchanger 138 can receive liquid from the compressor 178 and the high-pressure lift device 159.One or more controllers may control one or more components of fluid treatment system 100 B. High pressure lift device 159 may be a high pressure booster and low pressure lift device 128 may be a low pressure booster.

[0032] 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., refrigerant, homogeneous fluid, working fluid) that are circulated within the closed system of fluid treatment system 100B.

[0033] The 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, the controller actuates the one or more flow valves (not shown) based on the received sensor data.

[0034] 2A-E are exploded perspective views of a rotary PX 40 (e.g., a rotary pressure exchanger, a rotary liquid piston compressor (LPC)) in thermal communication with a thermal energy storage medium 180, 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.

[0035] The PX 40 is configured to transfer pressure and / or work between a first fluid (e.g., high-pressure working fluid, refrigerant, supercritical carbon dioxide, HPin fluid 130) and a second fluid (e.g., low-pressure working fluid, 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 or gas cooler, 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., 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., 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 .

[0036] 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) 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, such as 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.

[0037] 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).

[0038] In some embodiments, a controller 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., a system operator, a plant operator) can control the amount of fluid mixing within the PX 40. Additionally, by varying the rotational speed of the rotor 46 (e.g., via a motor), an operator can also control mixing. Three characteristics of the rotary PX 40 that affect mixing are (1) the aspect ratio of the rotor channel 70, (2) the exposure period between the first and second fluids, and (3) the 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, the rotor channel 70 (e.g., a small portion of the rotor channel 70) is used for pressure exchange between the first and second fluids.

[0039] In a thermal energy storage system, operation of the PX40 may proceed as follows: a low-pressure gaseous CO2 stream provided to the low-pressure inlet (LP-in) of the PX40 enters a duct and is sealed within the duct as the duct rotates past the LP-in port. When the duct is subsequently exposed to the high-pressure outlet, a pressure wave can be generated that compresses the low-pressure gaseous CO2 to a high pressure, increasing its temperature in the process. Thus, the low-pressure gaseous CO2 is converted to a high-pressure, high-temperature supercritical CO2 state. This high-pressure, high-temperature supercritical CO2 is then discharged through the high-pressure outlet (HP-out) port as high-pressure, medium-temperature supercritical CO2 enters the duct from the opposite end (e.g., the HP-in port) and pushes a portion of the now-compressed fluid out the HP-out port. A portion of the HP-in fluid is then sealed within the duct as the duct continues its rotation past the HP-in port. The duct is then exposed to the LP-out port, and an expansion wave propagates through the duct, converting the high-pressure, medium-temperature supercritical CO2 into a low-pressure, low-temperature two-phase gas-liquid mixture, which is discharged from the LP-out port.

[0040] 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, rotary PX 40 can be designed to operate with an internal piston or other barrier, either full or partial, that separates the first and second fluids while still allowing pressure transmission.

[0041] PX40 may be in a system (e.g., a thermal energy storage system) that also includes a thermal energy storage medium 180. The thermal energy storage medium may provide heat to the working fluid of PX40. The thermal energy storage medium may receive heat from the working fluid of PX40. The thermal energy storage medium may be in thermal communication with the working fluid of PX40. The thermal energy storage medium may be in thermal communication through one or more other components of the subsystem, such as one or more heat exchangers, secondary heat transfer fluids, etc. A fluid processing system may have one thermal energy storage system, e.g., to store heat for subsequent provision to a target area or target process, and to subsequently receive heat for cooling the target area or target component, etc. A fluid processing system may have multiple thermal energy storage systems, e.g., to pass heat between storage systems. As an example, a fluid processing system including PX40 may include a first "hot" thermal energy storage medium 180 maintained at a high temperature (compared to ambient temperature, a second energy storage medium, etc.) and a second "cold" thermal energy storage medium 180 maintained at a low temperature. The fluid processing system may be operated in cycles, such as a charge cycle (e.g., work is performed on a working fluid, acting as a heat pump) and a discharge cycle (e.g., the stored state of the thermal energy storage medium 180 is utilized to perform a target function). In some embodiments, the charge cycle may store thermal energy, and the discharge cycle may extract energy from the thermal energy storage medium 180, for example, via a generator in a heat engine system. In some embodiments, the charge cycle may generate a low-temperature thermal energy storage medium 180, and the discharge cycle may use the thermal energy storage medium 180 as a heat sink to cool a target location, component, material, etc. In some embodiments, the charge cycle can increase the temperature of the thermal energy storage medium 180 (e.g., by transferring heat from a lower temperature heat source), and the discharge cycle can utilize the high temperature heat for a target process (e.g., an industrial process).In some embodiments, PX40 may be utilized for one cycle of the fluid processing system and not for another cycle. For example, PX40 may be utilized during the charge cycle and not during the discharge cycle. A fluid processing system may include multiple architectures, for example, to include charge and discharge cycles. Fluid processing system architectures may have some overlap of components (e.g., thermal energy storage medium 180) and some exclusive components (e.g., PX40, main working fluid compressor, generator, etc.).

[0042] 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 higher-pressure refrigerant and a lower-pressure refrigerant) 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 rate of diffusion of the fluids, and / or the rotational speed of the rotor 46 can govern whether and to what extent mixing occurs. The PX 40 can be included in a thermal energy storage system, such as a system further including a thermal energy storage medium 180.

[0043] FIG. 2B is an exploded perspective view of an embodiment of a rotary PX 40 (e.g., a rotary LPC) according to certain embodiments. In FIG. 2B, a channel opening 72 is in a first position. In the first position, the channel opening 72 is in fluid communication with an aperture 78 in the end cover 64 and thus with the manifold 52, while the opposite channel opening 74 is in fluid communication with an aperture 82 in the end cover 66 and thus with the manifold 54. The rotor 46 can rotate in a clockwise direction, as indicated by arrow 84. 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.

[0044] 2C is an exploded perspective view of an embodiment of a rotating PX 40 (e.g., a rotating LPC), according to certain embodiments. In FIG. 2C, channel 70 has rotated clockwise through an arc of approximately 90 degrees. In this position, opening 74 (e.g., outlet) is no longer in fluid communication with apertures 80 and 82 in end cover 66, and opening 72 is no longer in fluid communication with apertures 76 and 78 in end cover 64. Thus, a low-pressure second fluid 86 is temporarily contained within channel 70.

[0045] 2D is an exploded perspective view of an embodiment of a rotating PX 40 (e.g., a rotating LPC), according to certain embodiments. In FIG. 2D, the channel 70 has been rotated through an arc of approximately 60 degrees from the position shown in FIG. 2B. 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 in the end cover 64. In this position, a first fluid 88 at high pressure enters and pressurizes a second fluid 86 at low pressure, driving the second fluid 86 out of the rotor channel 70 and through the aperture 80.

[0046] 2E is an exploded perspective view of an embodiment of a rotary PX 40 (e.g., a rotary LPC), according to certain embodiments. In FIG. 2E, channel 70 has rotated through an arc of approximately 270 degrees from the position shown in FIG. 2B. In this position, opening 74 is 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, 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.

[0047] 3A-C are schematic diagrams of thermal energy storage systems 300A-C (e.g., refrigeration systems, heat pump systems, power generation systems, energy transfer systems, energy storage systems, etc.) including a PX, according to some embodiments. Some of the components of one or more of FIGS. 3A-C may share one or more features, characteristics, functions, or structures with the components of FIGS. 1A-B and / or 2A-E. One or more systems of FIGS. 3A-3C and / or 3A-3C can be used to perform the operations of methods 500 and / or 600 described in FIGS. 5-6.

[0048] FIG. 3A is a schematic diagram of a thermal energy storage system 300A including a PX 310, according to some embodiments. In some embodiments, the thermal energy storage system 300A is a thermal energy transport system and / or a fluid processing system. The thermal energy storage system 300A can circulate a working fluid, such as a refrigerant, propane, ammonia, or CO2, to perform an energy storage operation. The thermal energy storage system 300A includes a first architecture 302 and a second architecture 304. The first architecture 302 can be configured to perform a charge cycle operation. The second architecture 304 can be configured to perform a discharge cycle operation. The charge cycle can be a heat pump cycle. The charge cycle can transfer heat from a lower temperature region (e.g., low-temperature heat exchanger 318) to a higher temperature region (e.g., high-temperature heat exchanger 329). The transfer of heat from the lower temperature region to the higher temperature region can be performed at the cost of energy to perform work on the system, such as performed by a compressor 322. PX 310 can reduce the energy requirements of the system by performing more efficient forms of working fluid compression and / or expansion, thereby reducing the amount of working fluid that must be compressed by compressor 322. PX 310 performs expansion work recovery; for example, PX recovers pressure energy from the high-pressure refrigerant fluid exiting high-temperature heat exchanger 329 and uses it to compress a portion of the low-pressure refrigerant vapor exiting low-temperature heat exchanger 318. Without PX 310, this pressure energy would be lost through expansion across the high-pressure valve in a typical heat pump system. PX 310 therefore reduces the amount of low-pressure working fluid that must be compressed by compressor 322, thereby reducing the energy consumption of compressor 322. This allows for more efficient charge cycles utilizing architecture 302 of thermal energy storage system 300A. Discharge cycles can transfer thermal energy from higher temperature regions to lower temperature regions.The discharge cycle can be used to generate energy for use (eg, as a heat engine) or to generate storage for use (eg, electricity).

[0049] PX310 may be included in the first architecture (e.g., utilized in the charge cycle of thermal energy storage system 100A). PX310 may be a rotary pressure exchanger. In some embodiments, PX310 is an isobaric or substantially isobaric heat exchanger. PX310 may be configured to exchange pressure between a first fluid and a second fluid. PX310 may be configured to receive a high-pressure first fluid via a high-pressure inlet (HPin) and a low-pressure second fluid via a low-pressure inlet (LPin). PX310 may be configured to exchange pressure between a high-pressure fluid and a low-pressure fluid. PX310 may be configured to provide a low-pressure first fluid via a low-pressure outlet (LPout) and a high-pressure second fluid via a high-pressure outlet (HPout). In some embodiments, PX310 is coupled to a motor (e.g., the rotation of a rotor of PX310 is controlled by the motor). In some embodiments, the motor controls the rotational speed of PX310. The mass flow rate (e.g., of the first fluid and / or the second fluid) through PX 310 may be related to the rotational speed of PX 310. In some embodiments, the pressure of a fluid (e.g., the first fluid) in one or more other components (e.g., high-temperature heat exchanger 329, low-temperature heat exchanger 318, etc.) may be related to the rotational speed of PX 310. In some embodiments, the controller receives sensor data from one or more sensors of motor thermal energy storage system 300A.

[0050] 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.

[0051] In some embodiments, fluid treatment system 300A includes a high-temperature heat exchanger 329 (e.g., gas cooler, condenser), a low-temperature heat exchanger 318 (e.g., evaporator), and a compressor 322. In some embodiments, fluid treatment system 300A is a thermal energy storage system. In some embodiments, high-temperature heat exchanger 329 is a heat exchanger that provides heat from a working fluid (e.g., first fluid, refrigerant, CO2) to the environment. In some embodiments, high-temperature heat exchanger 329 may be coupled to a thermal energy storage medium. Heat may be rejected from the working fluid in high-temperature heat exchanger 329 and absorbed by the thermal energy storage medium. The heat rejected by the thermal energy storage medium may be absorbed by the working fluid in high-temperature heat exchanger 329. Some variations of thermal energy storage media are discussed in connection with FIGS. 4A-D.

[0052] In some embodiments, the high-temperature heat exchanger 329 can act as a condenser, condensing the fluid flowing through the high-temperature heat exchanger 329 (e.g., while cooling the fluid). For example, the high-temperature heat exchanger 329 can cool the working fluid of the thermal energy storage system 300A, such as during a charge cycle or while the first architecture 302 is operating. The phase of the working fluid can change (e.g., condense) from gas to liquid within the high-temperature heat exchanger 329.

[0053] In some embodiments, the high-temperature heat exchanger 329 is a heat exchanger that does not condense the fluid flowing through it (e.g., it cools the fluid without condensing the fluid). For example, during a charge cycle, the high-temperature heat exchanger 329 can cool the working fluid of the thermal energy storage system 300A without condensing the fluid. In some embodiments, the pressure of the fluid in the high-temperature heat exchanger 329 exceeds the critical pressure of the fluid. In some embodiments, the high-temperature heat exchanger 329 is a gas cooler and does not condense the fluid (e.g., in a gaseous state). The high-temperature heat exchanger 329 can provide heat from the fluid (e.g., gas) to a corresponding environment. In some embodiments, the temperature of the fluid in the high-temperature heat exchanger 329 may be reduced, but the fluid may not condense (e.g., the fluid does not change from a gas phase to a liquid phase). In some embodiments, above the critical pressure of the fluid (e.g., the refrigerant), the thermodynamic distinction between the liquid and vapor phases of the fluid in the high-temperature heat exchanger 329 disappears and only a single fluid state exists, referred to as the supercritical state.

[0054] In some embodiments, the high-temperature heat exchanger 329 can provide heat to the working fluid of the thermal energy storage system 300A (e.g., during a discharge cycle). The high-temperature heat exchanger 329 can act as an evaporator, e.g., the working fluid can undergo a phase change to a gas based on the absorbed heat. The high-temperature heat exchanger 329, in some embodiments, may not act as an evaporator during a discharge cycle (e.g., the working fluid may not undergo a phase change in the high-temperature heat exchanger 329 during a discharge cycle).

[0055] The thermal energy storage system 300A includes a low-temperature heat exchanger 318 (e.g., in thermal communication with a thermal energy storage medium or environment maintained at a lower temperature range than the environment or thermal energy storage medium associated with the high-temperature heat exchanger 329). The low-temperature heat exchanger 318 can provide heat from a heat source (e.g., a low-temperature reservoir) absorbed by the system 300A to a working fluid during a charge cycle. The heat can be rejected to a heat sink (e.g., a high-temperature reservoir) via the high-temperature heat exchanger 329 (e.g., while the thermal energy storage system 300A is acting as a heat pump, during a charge cycle, while the system is operating in a first mode, etc.). In some embodiments, the working fluid facilitates heat transfer from an environment associated with the evaporator to an environment associated with the condenser during a charge cycle. In some embodiments, the working fluid facilitates heat transfer from an environment or thermal energy storage medium associated with the low-temperature heat exchanger 318 to an environment or thermal energy storage medium associated with the high-temperature heat exchanger 329 during a charge cycle. The compressor 322 of the thermal energy storage system 300A can increase the corresponding pressure of the working fluid along a flow path between the low-temperature heat exchanger 318 and the high-temperature heat exchanger 329. The compressor 322 can be active during a charge cycle. The compressor 322 can also be utilized during a discharge cycle, or other devices (e.g., pump 323) can be utilized during the discharge cycle. In some examples, different components (e.g., compressor, pump, etc.) can be utilized for different operating modes or conditions. For example, a compressor can be utilized during a charge cycle (e.g., for a supercritical working fluid and / or a gaseous working fluid) and a pump can be utilized during a discharge cycle (e.g., for a liquid working fluid). In some embodiments, the working fluid is CO2 or other refrigerated fluid. The working fluid can flow substantially in a cycle (e.g., from the high-temperature heat exchanger 329 to the PX 310 to the low-temperature heat exchanger 318 to the compressor 322 to the high-temperature heat exchanger 329).In some embodiments, a cycle may be associated with operation in a first mode, such as a charge cycle, and a different cycle (e.g., a different set of components, a different flow path, a different architecture, etc.) may be utilized for a second mode. The first architecture 302 may be associated with the first mode (e.g., a charge mode or charge cycle), and the second architecture 304 may be associated with operation in the second mode (e.g., a discharge mode or discharge cycle).

[0056] The thermal energy storage system 300A may include a turbine 324 that operates during a discharge cycle. During the discharge cycle, heat may be transferred from the high-temperature heat exchanger 329 (or an associated environment, thermal energy storage medium, etc.) to the low-temperature heat exchanger 318. Energy may be extracted from this heat flow; for example, the thermal energy storage system 300A may be operated as a heat engine (e.g., in a heat engine mode, a discharge mode, or a discharge cycle). The turbine 324 may be coupled to a generator 325 to produce electricity or other components to extract energy, work, or the like from the thermal energy storage system 300A. The turbine 324 may be configured to convert the energy of a working fluid into electrical energy.

[0057] In some embodiments, fluid processing system 300A includes a low-pressure booster and / or a high-pressure booster (not shown). Both the low-pressure booster and the high-pressure booster may be configured to increase (e.g., “boost”) the pressure of the working fluid before providing the fluid to, for example, the LPin and HPin ports of PX 310, respectively. For example, the low-pressure booster increases the pressure of the working fluid discharged from low-temperature heat exchanger 318 (e.g., received from PX 310). The high-pressure booster may increase the pressure of the working fluid discharged by PX 310. The working fluid may be combined (e.g., by the high-pressure booster) with fluid discharged from compressor 322 (e.g., upstream of the inlet of high-temperature heat exchanger 329) and provided to high-temperature heat exchanger 329. The low-pressure booster may increase the pressure by less than a threshold amount (e.g., operate across a pressure differential less than a threshold amount). In some embodiments, the low-pressure booster can increase the pressure of the working fluid by approximately 10 to 60 psi (approximately 68.95 to 413.69 kPa). The working fluid may experience a pressure loss (e.g., due to fluid friction losses in the piping) as the second fluid flows from the low-pressure booster to the LP-in inlet of the PX 310. The high-pressure booster can increase the pressure of the working fluid between the second outlet of the PX 310 and the inlet of the high-temperature heat exchanger 329. The high-pressure booster may increase the pressure by less than a threshold amount (e.g., may operate across a pressure differential less than a threshold amount). In some embodiments, the high-pressure booster can increase the pressure of the second fluid by approximately 10 to 60 psi (approximately 68.95 to 413.69 kPa). The high-pressure booster can increase the pressure of the working fluid to a pressure that substantially matches the pressure of the fluid discharged from the compressor 322 (e.g., the pressure of the high-temperature heat exchanger 329). In contrast to any booster, the compressor 322 may increase the pressure of the fluid above a threshold amount (e.g., the compressor 322 may operate at a pressure differential above a threshold amount). In some examples, the compressor 322 may increase the pressure by greater than about 200 psi (about 1.379 MPa).In some embodiments, one or more controllers control the flow rate of fluid through the PX 310 by controlling the flow rate of a booster pump, such as a low-pressure booster.

[0058] In some embodiments, the low-temperature heat exchanger 318 is a heat exchanger for exchanging (e.g., providing) corresponding thermal energy from the environment (e.g., an environmental medium) to the working fluid during a charge cycle. In some examples, the low-temperature heat exchanger 318 can receive heat (e.g., thermal energy) from the air of the environment and provide the heat to the working fluid. In some embodiments, during a charge cycle, the low-temperature heat exchanger 318 can receive heat from a thermal energy storage medium and provide the heat to the working fluid. In some embodiments, the low-temperature heat exchanger 318 can perform the opposite function during a discharge cycle. For example, during a discharge cycle, the low-temperature heat exchanger 318 can provide thermal energy from the working fluid to the environment, to a thermal energy storage medium, or the like. In some embodiments, the environment is a refrigerated space, such as the interior of a refrigeration unit or freezer, an interior space (e.g., of a building or vehicle), or any other space that is kept at a low temperature. In some examples, the environment can be the interior of a freezer or refrigerated section in a supermarket or warehouse. In some embodiments, the environment is alternatively a thermal energy heat storage medium configured to act as a subsequent heat sink to absorb heat from a target material or environment to be kept cool to provide heat to the high temperature heat exchanger 329 for thermal storage and later use.

[0059] In some embodiments, the high-temperature heat exchanger 329 is a heat exchanger for transferring corresponding thermal energy (e.g., heat) between the working fluid and the environment. In some embodiments, during operation in a first mode (e.g., charge cycle), the high-temperature heat exchanger 329 can provide heat from the working fluid of the thermal energy storage system 300A to the environment or thermal energy storage medium, and during operation in a second mode (e.g., discharge cycle), the high-temperature heat exchanger 329 can absorb heat from the environment or thermal energy storage medium and provide heat to the working fluid of the thermal energy storage system 300A.

[0060] The thermal energy storage system 300A may include one or more controllers. The controller may control the booster, various valves, and / or compressor of the system 300A. The controller may receive sensor data from one or more sensors of the system 300A. The sensors may include pressure sensors, flow sensors, and / or temperature sensors. The controller of the thermal energy storage system 300A may be operative to determine whether the thermal energy storage system 300A is operated in a first mode (e.g., charge mode) or a second mode (e.g., discharge mode). The determination of which mode to operate may be based on several factors. For example, during periods when electricity to operate the compressor 322 is abundant (e.g., above a threshold), thermal energy may be stored, and during periods when electricity is scarce (e.g., below a threshold), thermal energy may be used to generate electricity via the generator 325. Time of day, electricity prices, availability of renewable energy, etc. may contribute to the determination of whether to operate thermal energy storage system 300A in the first mode or the second mode. Additionally, the conditions of the thermal energy storage medium (e.g., temperature, percentage of material in target phase, etc.) may be utilized in determining whether to operate in the first mode or the second mode. Additionally, process requirements (e.g., heat requirements of industrial processes, cooling or heating requirements of heating ventilation and air conditioning systems, etc.) may be used in determining whether to operate in the first mode or the second mode.

[0061] The direction of thermal energy transfer (e.g., heat transfer) of system 300A may be reversible in some embodiments. For example, in a refrigeration / air conditioning / air-cooling implementation of system 300A, high-temperature heat exchanger 329, located outdoors, rejects heat (e.g., provides corresponding thermal energy from a refrigerated fluid to a corresponding environment), and low-temperature heat exchanger 318 absorbs heat (e.g., provides corresponding thermal energy from a refrigerated fluid to a corresponding environment). In a heat pump implementation of system 300A, high-temperature heat exchanger 329, located indoors, rejects heat to its indoor environment, and low-temperature heat exchanger 318 absorbs heat from its outdoor environment. In some embodiments, system 300A includes one or more valves (e.g., reversing valves, diverter valves, etc.) to reverse the function of system 300A (e.g., reverse the flow of thermal energy facilitated by system 300A). In some embodiments, one or more working streams may be reversed and / or diverted. In some examples, one or more reversing or diverting valves included in system 300A in some embodiments can direct liquid from compressor 322 toward the outdoor unit. Similar valves can direct liquid from compressor 322 to the outdoor unit.

[0062] The thermal energy storage system 300A may be utilized in a first mode (e.g., using components of the first architecture 302) or a second mode (e.g., using components of the second architecture 304). Operation in the first mode (e.g., charge cycle) may include utilizing abundant electrical power to store thermal energy. Storing the thermal energy may include providing heat to a thermal energy storage medium via a high-temperature heat exchanger 329.

[0063] In operation in the first mode, abundant electrical power may be utilized to operate the compressor 322. In the process of compression, the temperature of the working fluid may be increased. A portion of the working fluid not provided to the compressor 322 may be provided to a low-pressure inlet of the PX 310 and brought to a higher pressure through pressure exchange with other fluid streams in the PX 310. The temperature of the fluid compressed within the PX 310 may also be increased.

[0064] In a first mode of operation, the discharge fluid of compressor 322 and the high-pressure discharge fluid of PX 310 may be provided to high-temperature heat exchanger 329. The high-temperature working fluid (e.g., gas, supercritical fluid, etc.) rejects heat to a low-temperature thermal energy storage medium. The thermal energy storage medium may store heat by increasing its temperature and / or undergoing a phase change, depending on the temperature, storage medium, etc.

[0065] In the first mode of operation, after rejecting heat to the thermal energy storage medium, the working fluid may lose thermal energy and decrease in temperature. In the first mode, the output of the high-temperature heat exchanger 329 may be provided to the high-pressure inlet of PX 310 to exchange pressure with the low-pressure fluid stream of PX 310. The working fluid exits the low-pressure outlet of PX 310.

[0066] In operation in the first mode, the fluid discharged by the low-pressure outlet of PX 310 may be provided to low-temperature heat exchanger 318. The low-pressure fluid (e.g., a two-phase gas-liquid mixture) may absorb heat from a thermal energy storage medium in thermal communication with the low-temperature heat exchanger 318. The working fluid may be evaporated in the low-temperature heat exchanger 318, e.g., to become a working gas. A first portion of the low-pressure low-temperature gas may be provided to compressor 322, and a second portion of the low-pressure low-temperature gas may be provided to a low-pressure inlet of PX 310. In some embodiments, the temperature difference between the thermal energy storage medium in communication with high-temperature heat exchanger 329 (e.g., high-temperature thermal energy storage medium) and the thermal energy storage medium in communication with low-temperature heat exchanger 318 (e.g., low-temperature thermal energy storage medium) may be large. The efficiency of operation in the second mode may depend on the temperature difference between the two thermal energy storage media.

[0067] Operation of system 300A in the first mode may include a charge cycle. During the charge cycle, the system may receive low-pressure, low-temperature refrigerant (e.g., working fluid, CO2) vapor from the outlet of low-temperature heat exchanger 318 and compress it to a high pressure in a process that increases its temperature. The high-pressure refrigerant thus produced may be in a subcritical vapor state (pressure below the refrigerant's critical pressure) or a supercritical state (pressure and temperature above the refrigerant's critical point). The high-pressure, high-temperature vapor thus produced may be heat exchanged with a thermal energy storage medium via high-temperature heat exchanger 329 (e.g., as depicted in any one or more of Figures 4A-D). A thermal energy storage medium configured in thermal communication with high-temperature heat exchanger 329 may store this high-temperature heat as sensible heat (i.e., via a temperature increase) or as latent heat (i.e., via a phase change from solid to liquid or liquid to gas). After rejecting heat to the heat storage medium, the high-pressure refrigerant vapor may cool and condense to a liquid state (in the subcritical case) or remain in a supercritical state (in the supercritical case), but at a lower temperature. This cooler, high-pressure refrigerant then enters PX 310 through the HPin port and may expand to a lower pressure. As it expands, the temperature of the working fluid decreases and it may change phase to a two-phase vapor-liquid mixture. This low-temperature two-phase vapor-liquid mixture exits PX 310 through the LPout port and enters the low-temperature heat exchanger 318, where it may absorb heat from a low-temperature heat storage medium in thermal communication with the low-temperature heat exchanger 318, e.g., water or a water / ice slurry, which may take the form represented by any one or more of Figures 4A-D. As the refrigerant absorbs heat from the low-temperature storage medium, the low-temperature medium may change phase (e.g., liquid gradually becoming more of an ice slurry with an increasing mass of ice fraction). After absorbing heat, the refrigerant liquid may evaporate and become a pure vapor at the outlet of the low-temperature heat exchanger 318. This refrigerant vapor may then exit the low-temperature heat exchanger and split into two streams. One stream may enter the LPin port of the PX 310, and the other stream may enter the inlet of the compressor 322.PX310 compresses a portion of the low-pressure, low-temperature refrigerant vapor entering its LP-in port and converts it to a high-pressure, high-temperature vapor or supercritical fluid. Compressor 322 compresses the remaining portion of the refrigerant vapor into a high-pressure, high-temperature vapor or supercritical fluid. The two high-pressure, high-temperature streams (one from PX310 and the other from compressor 322) combine and proceed to reject heat to a high-temperature thermal energy storage medium through high-temperature heat exchanger 329. The cycle then repeats, allowing the thermal energy storage device to continue charging.

[0068] Thermal energy storage system 300A may also be operated in a second mode in which the temperature difference between a high temperature reservoir (e.g., a high temperature thermal energy storage device associated with high temperature heat exchanger 329) and a low temperature reservoir (e.g., a low temperature thermal energy storage device associated with low temperature heat exchanger 318) may be utilized to extract energy from the system, perform work, perform a target function, etc.

[0069] In some embodiments, when power (e.g., electricity) is scarce, the thermal energy storage system 300A can be operated in a second mode that can discharge the thermal energy storage device for the performance of one or more target functions.

[0070] During operation in the second mode, a low-pressure working fluid, which may be a gas, liquid, or supercritical fluid, may be compressed or pumped to a high pressure, for example, by pump 323. The working fluid may then be provided to high-temperature heat exchanger 329.

[0071] While operating in the second mode, the working fluid may absorb heat from the high-temperature thermal energy storage medium in the high-temperature heat exchanger 329. The temperature of the working fluid may increase. The enthalpy of the working fluid may increase.

[0072] The high-pressure, high-temperature working fluid may be provided to turbine 324. In the turbine, the high-pressure, high-temperature working fluid may expand over the turbine and its pressure may be reduced. Turbine 324 may extract mechanical work from the working fluid through this process. The extracted work may rotate a rotor of the turbine, and the motion of the rotor may be used to perform a target function, such as using the rotor's motion to drive generator 325 to generate electricity. In some embodiments, more power may be produced by generator 325 than is consumed by pump 323, resulting in a net increase in stored or generated power during operation in the second mode (e.g., during a discharge cycle).

[0073] During operation in the second mode, the working fluid exiting the turbine may be at a higher temperature than the cold / low-temperature thermal energy storage medium communicated with the low-temperature heat exchanger 318. As the working fluid passes through the low-temperature heat exchanger 318, the working fluid may reject heat to the thermal energy storage medium. In some embodiments, the working fluid may condense to a liquid state. Determining whether to operate at a temperature at which the working fluid condenses may be made in terms of the target performance of the thermal energy storage system 300A, such as a target efficiency, a target level of cycle optimization, etc. The size (e.g., thermodynamic energy capacity) of the one or more thermal energy storage media may be determined based on a target power generation goal, a target power generation time span, etc. In some embodiments, the high-temperature heat exchanger 329 may represent two or more physical heat exchangers, where a different heat exchanger is used during the discharge cycle than the heat exchanger used during the charge cycle. Similarly, in some embodiments, the low-temperature heat exchanger 318 may represent two or more physical heat exchangers. This configuration allows for the use of two different working fluids (e.g., refrigerants) during the charge and discharge cycles. In some embodiments, both the charge and discharge cycles can use CO2 as the working fluid, while in other embodiments, the charge cycle can use CO2 as the working fluid and the discharge cycle can use air or an organic Rankine fluid (e.g., butane, pentane, hexane, silicone oil, etc.) as the working fluid.

[0074] 3B is a schematic diagram of a thermal energy storage system 300B including a pressure exchanger (PX), according to some embodiments. In some embodiments, the thermal energy storage system 300B is a thermal energy transport system and / or a fluid processing system. 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 the thermal energy storage system 300B may have similar properties, structures, and / or functions as features of the thermal energy storage system 300A of FIG. 3A.

[0075] The thermal energy storage system 300B may include the capability to operate in a first operating mode 301 and a second operating mode 303 (e.g., a charge mode and a discharge mode). The first operating mode 301 may correspond in one or more features to the first architecture 302 of Figure 3A. The second operating mode 303 may share one or more features with the second architecture 304 of Figure 3A.

[0076] The thermal energy storage system 300B includes a controller 326, a three-way valve 328, and a flow control valve 330. The controller 326 can receive inputs. The inputs can include sensor data, user input, time data, etc. For example, the controller 326 can be coupled to a device that receives user inputs for determining whether to operate the thermal energy storage system 300B in a first mode or a second mode. The controller 326 can receive sensor data (e.g., associated with a state of one or more thermal energy storage media, associated with energy availability / scarcity, etc.) and determine whether to operate the thermal energy storage system 300B in the first mode or the second mode based on the input data.

[0077] Upon determining that thermal energy storage system 300B is to be operated in the first mode, controller 326 may provide control signals to one or more components. For example, three-way valve 328 and / or flow control valve 330 may be operably coupled to controller 326 and operate based on the control signals received from controller 326.

[0078] To operate thermal energy storage system 300B in a first mode, controller 326 can actuate three-way valve 328 to allow flow from high-temperature heat exchanger 329 to PX 310 and disable flow from high-temperature heat exchanger 329 to turbine 324 (e.g., during a charge cycle, as shown by the dashed fluid flow path). During operation in the first mode, energy can be input into thermal energy storage system 300B (e.g., via compressor 322) rather than extracted via turbine 324. To operate thermal energy storage system 300B in the first mode, controller 326 can further provide a control signal to flow control valve 330. The signal provided to flow control valve 330 can determine the portion of the fluid discharged by low-temperature heat exchanger 318 that is provided to PX 310 and the portion that is provided to compressor 322. The determination of the portions of the fluid stream provided to compressor 322 and PX 310 during operation in the first mode may be determined by the capabilities and / or capacity of PX 310, the capabilities of compressor 322, the conditions of the fluid system (e.g., temperature and pressure), the heat source and / or sink conditions (e.g., temperature, mass, heat absorption of various thermal energy storage media, etc.), ambient conditions, energy efficiency or heat transfer rate optimization, or other parameters of interest. The portion of the fluid discharged by the low-temperature heat exchanger 318 may be compressed to a higher pressure by compressor 322, while the portion of the fluid discharged by the low-temperature heat exchanger 318 may also be compressed by exchanging pressure with other fluid streams within PX 310.

[0079] Upon determining that the thermal energy storage system 300B is to be operated in the second mode, the controller 326 may provide additional control signals to one or more components. The three-way valve 328, the flow control valve 330, and other components of the thermal energy storage system 300B may be provided control signals by the controller 326.

[0080] To operate thermal energy storage system 300B in a second mode, three-way valve 328 can be actuated by controller 326 to provide flow to turbine 324 and disable flow to PX 310 (as shown by the dashed working fluid flow path in FIG. 3B). Working fluid can flow to turbine 324, thereby rotating turbine 324 to perform a target function (e.g., generating electricity). In the second mode, thermal energy from the storage device can be consumed (e.g., via a thermal energy storage medium in thermal communication with high-temperature heat exchanger 329) to perform the target function, causing turbine 324 to rotate. To operate thermal energy storage system 300B in the second mode, flow control valve 330 can be actuated by controller 326 to disable fluid flow to PX 310. The working fluid may be compressed by compressor 322 (or a different device than utilized in the first mode, as shown in FIG. 3A). The compressed working fluid is then provided to the high temperature heat exchanger 329 during operation of the thermal energy storage system 300B in the second mode of operation.

[0081] The controller 326 can provide additional control signals to additional components. For example, in some embodiments, the compressor 322 can be operated at different speeds or otherwise in the first and second modes. The controller 326 can provide one or more control signals to regulate the operation of the compressor 322. In some embodiments, the operation of the compressor 322 may actually be performed by multiple devices, such as a set of compressors, a pump, etc., and different devices may be utilized for different operating conditions, different target working fluid conditions, different target applications, different operating modes, etc. The controller 326 can provide control signals to any valves to regulate any of these devices and the flow paths to and / or from such devices as part of operating in the first or second operating modes. In some embodiments, additional components may be included in the thermal energy storage system, with further control provided by the controller 326. It will be understood that the controller 326 can represent a single device or multiple devices each performing a single function, or a combination of these descriptions. The controller 326 may be a dedicated device, a general-purpose computing system, a microcontroller, a processing device coupled to a memory, or any other device capable of providing control signals to one or more components based on receiving one or more inputs.

[0082] The controller 326 may also provide control signals to one or more thermal energy storage medium systems. For example, in some embodiments, the thermal energy storage medium or associated heat transfer fluid of the high-temperature thermal energy storage system 380 may be pumped through the high-temperature heat exchanger 329 to thermally contact the working fluid of the thermal energy storage system 300B. The thermal energy storage medium or associated heat transfer fluid of the low-temperature thermal storage system 381 may be pumped through the low-temperature heat exchanger 318 to thermally contact the working fluid of the thermal energy storage system 300B. The controller 326 may provide control signals to the thermal energy storage medium systems to determine the rate, direction, etc. of transport of the thermal energy storage medium (e.g., between the high-temperature and low-temperature reservoirs). Examples of thermal energy storage medium systems are described in connection with FIGS. 4A-D . In some embodiments, separate high-temperature heat exchanger 329 and / or low-temperature heat exchanger 318 may be utilized for operation in charge and discharge modes. In some embodiments, separate charge and discharge architectures may be included in a system, such as thermal energy storage system 300B, with the thermal energy storage medium in thermal communication with a first heat exchanger associated with the charge architecture and a second heat exchanger associated with the discharge architecture.

[0083] 3C illustrates a thermal energy storage system 300C for generating a heat sink for cooling a target environment, according to some embodiments. Thermal energy storage system 300C may share one or more features with thermal energy storage systems 300A and / or 300B. For example, components labeled with the same reference numbers may perform similar functions, share similar features, etc.

[0084] Thermal energy storage system 300C includes several optional components that may be included in other thermal energy storage systems. For example, thermal energy storage system 300C may include flash tank 313 (e.g., a receiver). In some embodiments, flash tank 313 is a receiver configured to receive a flow of fluid (e.g., a first fluid) discharged from a low-pressure outlet of PX 310. Flash tank 313 may form a chamber that collects the first fluid from the first outlet of PX 310. Flash tank 313 may receive the first fluid in a two-phase state (e.g., liquid and gas). In some embodiments, flash tank 313 is a tank constructed of welded sheet metal. Flash tank 313 may be made of steel (e.g., steel plate, steel sheet, etc.). The first fluid (at low pressure) may separate into gas and liquid inside flash tank 313. Liquid of the first fluid may settle to the bottom of flash tank 313, while vapor of the first fluid may rise to the top of flash tank 313. Liquid may flow from flash tank 313 toward low-temperature heat exchanger 318 (e.g., via expansion valve 316). The chamber of flash tank 313 may be maintained at a set pressure. The pressure may be set by a user (e.g., an operator, technician, engineer, etc.) and / or by a controller (e.g., controller 380). In some embodiments, the pressure of flash tank 313 is controlled by one or more valves (e.g., flash gas valve 320, pressure regulator valve, safety valve, etc.). In some embodiments, flash tank 313 includes at least one pressure sensor (e.g., a pressure transducer).

[0085] The thermal energy storage system 300B may include an expansion valve 316. In some embodiments, the expansion valve 316 is disposed along a flow path between the flash tank 313 and the low-temperature heat exchanger 318. The expansion valve 316 may be an adjustable valve (e.g., an electronic expansion valve, a thermostatic expansion valve, a ball valve, a gate valve, a poppet valve, etc.). The expansion valve 316 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 316 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 316 is a thermal expansion valve. The expansion valve 316 may be actuated (e.g., opened or closed) based on temperature data associated with the low-temperature heat exchanger 318 (e.g., temperature data of the working 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 316 may increase or decrease pressure on a diaphragm of the expansion valve 316, causing a poppet valve coupled to the diaphragm to open or close, causing more or less fluid flow to the cold heat exchanger 318, thereby causing more or less expansion of the fluid. The expansion valve sensing bulb may be located near the downstream end of the cold heat exchanger 318 (e.g., near the fluid outlet of the cold heat exchanger 318) and may be fluidly connected to the diaphragm via a sensing capillary (e.g., a conduit between the sensing bulb and the cold heat exchanger valve 316). In some embodiments, the expansion valve 316 is controlled and operated entirely based on electronic commands (e.g., from the controller 380).

[0086] Thermal energy storage system 300B may include a flash gas valve 320 to regulate the flow of gas on a flash gas bypass path. In some embodiments, flash gas valve 320 is a bypass valve that regulates the flow of gas from a gas outlet of flash tank 313 so that it can be combined with the discharge of low-temperature heat exchanger 318. In some embodiments, the flow of gas from flash tank 313 flows along the flash gas bypass path and bypasses low-temperature heat exchanger 318. In some embodiments, the flash gas path is between flash tank 313 and a location downstream of the outlet of low-temperature heat exchanger 318. The gas flowing along the flash gas bypass path may be combined with the discharge of low-temperature heat exchanger 318. The flash gas valve 320 may expand (e.g., reduce the pressure of) the gas collected in flash tank 313 as the gas flows toward compressor 322. In some embodiments, flash gas valve 320 may be an adjustable valve. In some embodiments, the flush gas valve 320 is actuated by the controller 380 based on sensor data, time / date data, user input, energy availability data, environmental data, and the like.

[0087] In some embodiments, such as illustrated in FIG. 3C , LP booster 314 receives a fluid flow from flash tank 313. In some embodiments, LP booster 314 receives a gas flow from flash tank 313. In some examples, LP booster 314 receives a portion of the gas flowing along the flash gas bypass flowpath between flash tank 313 and flash gas valve 320. In some embodiments, LP booster 314 receives the fluid and increases the pressure of the fluid to form a second fluid (e.g., at a second pressure). The fluid is provided as the second fluid to a second inlet of PX 310 at the increased pressure (e.g., the second pressure). In some embodiments, LP booster 314 is a compressor or pump operating across a low pressure differential to “boost” the pressure of the gas received from flash tank 313. In some embodiments, the HP booster 385 is a compressor or a pump that operates across a low pressure differential to "boost" the pressure of a fluid (e.g., a second fluid) received from the second outlet of the PX. In some embodiments, a compressor is configured to increase the pressure of a fluid that is substantially composed of a gas, while a pump is configured to increase the pressure of a fluid that is substantially composed of a liquid.

[0088] The thermal energy storage system 300C further includes a secondary loop of components in thermal communication with the primary working fluid loop via a low-temperature heat exchanger 318. The thermal energy storage system 300C may be configured to remove heat from the thermal storage medium 342 (e.g., in a first mode of operation, at a time when energy is abundant, during a charge cycle) and store heat in a high-temperature heat exchanger 329 (e.g., a gas cooler or condenser in an outdoor environment to reject heat from the thermal storage medium 342). The secondary loop may include a second energy transfer fluid, which may be the same or different from the fluid utilized in the loop including the PX 310. For example, the secondary working fluid may be CO2, glycol, a water / glycol mixture, or other fluid for thermal energy transfer between the low-temperature heat exchanger 318 and the storage medium 342.

[0089] While operating in the second mode, the thermal energy storage system 300C may be configured to utilize heat sinks generated during operation in the first mode in the storage medium 342 to remove thermal energy from the target location. In some embodiments, a cooling coil 344 in communication with a fan 350 may be utilized to provide a flow of cool air during operation in the second mode, for example, to cool a building or other interior space. In some embodiments, the charge cycle operation may occur during a first time (e.g., when the external temperature surrounding the high temperature heat exchanger 329 is low, when energy costs are low, when the target area to be cooled is unoccupied, etc.), and the discharge cycle may occur during a second time (e.g., when energy costs are high, when the target area is occupied).

[0090] The storage medium 342 can provide a method for exchanging heat between the secondary working fluid of the secondary loop and the storage medium 342. For example, the reservoir containing the storage medium 342 can include one or more channels through the reservoir through which the secondary working fluid flows to exchange thermal energy with the storage medium 342. In some embodiments, the storage medium can be a phase change material. The storage medium can be water, ice, an ice / water mixture or slurry, or other types of thermal energy storage media.

[0091] One or more valves, such as a temperature modulation valve 348 and one or more three-way valves 346, may be included in the thermal energy storage system 300C. During operation in a first mode (e.g., charge mode, ice-making mode, etc.), the flow of the secondary working fluid may be directed through the storage medium 342, for example, to maximize energy transfer between the secondary working fluid and the storage medium 342. During operation in the first mode, flow bypassing the storage medium 342 may be limited or disabled, for example, by activating the temperature modulation valve 348. During operation in the first mode, an air handling unit, air conditioning unit, refrigeration unit, or the like (e.g., cooling coil 344) may be bypassed. During operation in the first mode, the cooling coil 344 may be bypassed by activation of the three-way valve 346.

[0092] During operation in a second mode (e.g., discharge mode, air conditioning mode, air cooling mode, etc.), the three-way valve 346 may be operated to provide a flow of secondary working fluid to the cooling coil 344. In some embodiments, the three-way valve 346 may be replaced with a flow control valve, for example, to provide control over the flow rate of fluid through the cooling coil 344. During operation in the second mode, the temperature modulation valve 348 may be operated. The temperature modulation valve 348 may be operated to provide a targeted mix of secondary working fluid that has passed through the storage medium 342 and secondary working fluid that has not. The temperature modulation valve 348 may be operated to provide secondary working fluid to the cooling coil 344 at a targeted temperature, for example, to improve operation of the air conditioning or refrigeration function of the thermal energy storage system 300C.

[0093] The controller 380 can provide control signals to one or more components of the thermal energy storage system 300C. The controller 380 can provide control signals to the components of the thermal energy storage system 300C to determine the operating mode of the system. In some embodiments, the primary loop including the PX 310 can be operated only in a first mode, a charge cycle, etc. In some embodiments, the pump 340 can circulate the secondary working fluid in both the charge mode and the discharge mode. In some embodiments, the cooling coil 344 and / or the fan 350 can operate only in the discharge mode.

[0094] To operate in the first mode, the controller 380 may provide a control signal to the temperature modulation valve 348 to transfer heat from the storage medium 342 to the secondary working fluid and cause the secondary working fluid to flow through the storage medium 342. To operate in the first mode, the controller 380 may provide a control signal to the three-way valve 346 to bypass the cooling coil 344. The controller 380 may also provide control signals to cause operation of the HP booster 385, the compressor 322, the LP booster 314, the flash gas valve 320, the expansion valve 316, etc. to operate in the first mode. For example, these components may operate to perform various functions on the primary working fluid while operating in the first mode. Adjustment of the operation of one or more components may be implemented via the controller 380, for example, by providing control signals to the components based on input data to the controller 380.

[0095] To operate in the second mode, the controller 380 provides a control signal to the temperature modulated valve 348 to cause a portion of the secondary working fluid to flow through the storage medium 342 and a portion to bypass the storage medium 342. This portion may be determined based on data generated by a temperature sensor provided as an input to the controller 380. This portion may be determined to maintain the temperature of the fluid exiting the temperature modulated valve 348, the fluid entering the cooling coil 344, etc. To operate in the second mode, the controller 380 may provide a control signal to the three-way valve 346, for example, to provide a flow of the secondary working fluid to the cooling coil 344. To operate in the second mode, the controller 380 may provide a control signal to the fan 350, for example, to increase heat transfer between the environment proximate the cooling coil 344 and the secondary working fluid in the cooling coil 344. The controller 380 may also provide a control signal to the pump 340 to regulate operation of the pump 340 (e.g., based on a target energy transfer characteristic).

[0096] Figures 4A-D show systems for managing thermal energy storage media, according to some embodiments. The systems shown in Figures 4A-D can be associated with high-temperature thermal energy storage systems. The systems shown in Figures 4A-D can be associated with low-temperature thermal energy storage systems. Any of the systems shown in Figures 3A-3C can include one or more of the thermal energy storage media systems shown in Figures 4A-D. Any of the thermal energy storage solutions shown in Figures 4A-D can be in thermal communication with either the high-temperature or low-temperature heat exchangers shown in Figures 3A-C.

[0097] 4A illustrates an exemplary thermal energy storage medium management system 400A, according to some embodiments. The thermal energy storage medium management system 400A can include multiple reservoirs, such as a high-temperature storage device 402 and a low-temperature storage device 404. The thermal energy storage system 400A can be configured to place the thermal energy storage medium in thermal contact with a heat exchanger 406 to exchange energy with a working fluid of a thermal energy storage system, including, for example, a PX, such as those shown in FIGS. 3A-3C. The thermal energy storage system 400A can be in thermal communication with the high-temperature heat exchanger 329, the low-temperature heat exchanger 318, etc.

[0098] The thermal energy storage management system 400A may include one or more pumps (e.g., pump 408) for transferring the thermal energy storage medium between the reservoirs. In some embodiments, multiple pumps may be utilized, and multiple flow paths may be utilized, facilitating transfer between the reservoirs in multiple directions. In some embodiments, more than two reservoirs may be included, for example, any number of hot and cold storage reservoirs may be included. The pumps, valves, etc. that determine the flow path of the thermal energy storage material between the reservoirs may be controlled based on control signals provided by one or more controllers (e.g., controller 380 of FIG. 3C ).

[0099] During operation in a mode in which the thermal energy storage medium absorbs heat from the working fluid, the pump 408 can transfer the storage medium from the cold storage device 404 to the hot storage device 402. The use of "hot" and "cold" in the context of a thermal energy storage system is relative; for example, the entire storage system can be maintained above or below some temperature, such as ambient conditions, a target temperature of the system, etc., with the cold storage device 404 at a lower temperature than the hot storage device 402. During operation in a mode in which thermal energy is transferred from the thermal storage medium to the working fluid through the heat exchanger 406, the pump 408 can transfer heat to the working fluid in the heat exchanger 406, lowering the temperature of the thermal energy storage medium, as the thermal energy medium is transferred from the hot storage device 402 through the heat exchanger 406 to the cold storage device 404. The pump 408 can be included in a fluid transfer system, a fluidized sand transfer system, or the like.

[0100] In some embodiments, heat exchanger 406 may be a high-temperature heat exchanger, such as high-temperature heat exchanger 329. During operation in a first mode (e.g., charge mode), pump 408 can cause thermal energy storage medium to be transferred from cold storage device 404 to hot storage device 402, increasing the temperature of the thermal energy storage medium through thermal communication with the working fluid of the thermal energy storage system in heat exchanger 406. When heat exchanger 406 is a high-temperature heat exchanger, during operation in a second mode (e.g., discharge mode), pump 408 can cause thermal energy storage medium to be transferred from hot storage device 402 to cold storage device 404, increasing the temperature of the working fluid through thermal interaction in heat exchanger 406.

[0101] In some embodiments, heat exchanger 406 may be a low-temperature heat exchanger, such as low-temperature heat exchanger 318. During operation in a first mode (e.g., a charge cycle), pump 408 may transfer a thermal energy storage medium from high-temperature storage device 402 to low-temperature storage device 404, providing heat to the working fluid in heat exchanger 406. When heat exchanger 406 is a low-temperature heat exchanger, during operation in a second mode (e.g., a discharge cycle), pump 480 may transfer a thermal energy storage medium from low-temperature storage device 404 to high-temperature storage device 402, absorbing heat from the working fluid in heat exchanger 406.

[0102] Various thermal energy storage media may be utilized in connection with systems such as the thermal energy storage management system 400A. The thermal energy storage medium may include molten salt (e.g., a mixture of sodium nitrate and potassium nitrate). The molten salt may be maintained in the cryogenic storage device 404 at at least the melting temperature of the salt (e.g., approximately 220°C). The thermal energy storage medium may be or include sand. The pump 408 may be replaced, augmented, etc. with a pneumatic sand transfer system. The heat exchanger 406 may be configured to support transport of the fluidized sand, heat exchange between the fluidized sand and the working fluid, etc.

[0103] FIG. 4B illustrates a thermal energy storage medium reservoir 400B, according to some embodiments. In some embodiments, a heat exchanger 410 (e.g., high-temperature heat exchanger 329, low-temperature heat exchanger 318) can be embedded within a thermal energy storage medium 412. The thermal energy storage medium 412 can include one or more materials for storing heat, creating a heat sink, etc. Heat can be transferred between the working fluid and the thermal energy storage medium by contacting the working fluid with the heat exchanger embedded within the thermal energy storage medium 412. In some embodiments, the heat exchanger can be a pillow plate embedded in a tank containing the thermal energy storage medium 412, for example, water. The working fluid can be fluidly connected to a system, such as the system shown in FIGS. 3A-C, for example, a thermal energy transfer system including a PX.

[0104] The thermal energy storage medium 412 can be any material that can store or extract heat (e.g., "store cold" or create a heat sink). In some embodiments, the thermal energy storage medium 412 can be a material that changes phase during a target temperature transition for heat storage. For example, the thermal energy storage medium 412 can be, for example, water surrounding a low-temperature heat exchanger (e.g., a water and ice mixture, a water / ice slurry, etc.). The thermal energy storage medium 412 can be, for example, a high-temperature phase change material surrounding a high-temperature heat exchanger (e.g., paraffin, octadecane, salt hydrates, fatty acids, esters, ionic liquids, etc.). The thermal energy storage medium 412 can be or include a phase-change heat storage medium. The use of a high-temperature phase-change material can be utilized to upgrade the heat of industrial waste to high-temperature (e.g., high-grade) heat that is stored in the thermal energy storage medium 412. The high temperature heat stored in the thermal energy storage medium 412 can be transferred via a heat transfer system to a target process (eg, a high temperature industrial process) for use of the high temperature heat in the process.

[0105] FIG. 4C illustrates a thermal energy gradient storage system 400C according to some embodiments. The thermal energy gradient storage system 400C includes a temperature gradient storage device 414. The temperature gradient storage device 414 may include or contain a thermal energy storage medium (either solid or liquid) capable of maintaining a temperature gradient, for example, from the top to the bottom of a storage reservoir. As an example, the temperature gradient storage device 414 may include sand at different temperatures depending on the height within the reservoir. The hot and cold regions of the storage medium are separated by a thermocline, e.g., a temperature gradient. In the case of a liquid-based storage medium, the density difference between the hot and cold portions of the storage medium creates a thermal layer in the fluid within the reservoir, helping to stabilize and maintain the thermocline. The thermal energy gradient storage system 400C may be configured to place the thermal energy storage medium in thermal communication with a heat exchanger 416, which may be in thermal communication with the working fluid of a thermal energy transfer system including a PX, such as those shown in FIGS. 3A-3C.

[0106] In a first mode, a low temperature heat storage medium may be provided to the heat exchanger 416 and may absorb heat from a working fluid also provided to the heat exchanger 416. For example, during a charge cycle, the low temperature heat storage device may be placed in thermal communication with the working fluid and may increase the temperature of the storage medium. In a second mode, a high temperature storage medium may be provided to the heat exchanger 416 and may provide heat to the working fluid in the heat exchanger 416. For example, during a discharge cycle, the high temperature heat storage device may be placed in thermal communication with the working fluid in the heat exchanger 416 and may increase the temperature of the working fluid.

[0107] In some embodiments, a pump 418 (e.g., a pneumatic pump for conveying fluidized sand) can provide transport of the thermal energy storage medium from the bottom of the thermal gradient storage device 414 to the top of the thermal gradient storage device 414. The thermal gradient storage device 414 may be gravity-fed, e.g., the position of the thermal storage medium within the reservoir may be regulated by gravity. The pump 418 may be replaced or augmented with a conveyor belt or other mechanical device to convey the thermal energy storage medium to the top of the reservoir. The pump 418 may be included in a fluid delivery system, a fluidized sand delivery system, etc.

[0108] In some embodiments, the thermal gradient storage device 414 may be filled or substantially filled with a low-temperature thermal storage medium. The storage medium may be provided to the heat exchanger 416 from the bottom of the thermal gradient storage device 414. The temperature of the storage medium may be raised by interaction with the working fluid in the heat exchanger 416 (e.g., during a charge cycle). The high-temperature storage medium may then be exchanged at the top of the thermal gradient storage device 414. This process may continue until the thermal gradient storage device 414 is filled or substantially filled with a high-temperature thermal energy storage medium, for example, to store thermal energy. During operation in the second mode, the thermal gradient storage device 414 filled or substantially filled with a high-temperature thermal energy storage medium may be provided to the heat exchanger 416. The high-temperature thermal energy storage medium may interact with the working fluid in the heat exchanger 416 and transfer heat to the working fluid (e.g., during a discharge cycle). The low-temperature thermal energy storage medium may be exchanged at the top of the thermal gradient storage device 414. This process can continue until the thermal gradient storage device 414 is filled or substantially filled with the low temperature thermal energy storage medium.

[0109] FIG. 4D illustrates a thermal energy storage medium system 400D including a secondary energy transfer fluid, according to some embodiments. A thermal energy storage medium reservoir 420 can include a storage medium through which a secondary heat transfer fluid is passed, for example, by a pump 424. The thermal energy storage medium system 400D can be configured to place the secondary heat transfer fluid in thermal communication with a heat exchanger 422. The heat exchanger 422 can be in thermal communication with a working fluid of a thermal energy transfer system and / or a thermal energy storage system, including, for example, one of the systems shown in FIGS. 3A-3C , including a PX. The thermal energy storage medium reservoir 420 can include a solid-phase thermal energy storage medium. For example, the thermal energy storage medium reservoir can include natural stone (e.g., high heat capacity rock, lava rock, extrusive igneous rock, volcanic cinder, etc.), artificial stone (e.g., brick, concrete), or sand.

[0110] The thermal energy storage medium system 400D includes a pump 424 that transfers a secondary heat transfer fluid through the thermal energy storage medium reservoir 420 and places the secondary heat transfer fluid in thermal communication with the thermal energy storage medium. The secondary heat transfer fluid can be provided to a heat exchanger 422 where it can exchange thermal energy with a primary working fluid of the thermal energy storage system. The pump 424 can be included in a fluid transfer system, a fluidized sand transfer system, or the like.

[0111] In a mode for increasing the temperature of the thermal energy storage medium reservoir 420 (e.g., a charge cycle if the heat exchanger 422 is a high-temperature heat exchanger, or a discharge cycle if the heat exchanger 422 is a low-temperature heat exchanger), the secondary fluid may be circulated through the thermal energy storage medium reservoir 420, in thermal contact with the high-temperature working fluid in the heat exchanger 422, and returned to the thermal energy storage medium reservoir 420 to transfer heat to the thermal energy storage medium and increase the temperature of the storage medium. In a mode for decreasing the temperature of the thermal energy storage medium reservoir 420 (e.g., a charge cycle if the heat exchanger 422 is a low-temperature heat exchanger, or a discharge cycle if the heat exchanger 422 is a high-temperature heat exchanger), the high-temperature secondary fluid may be provided from the thermal energy storage medium reservoir 420 to the heat exchanger 422 to provide thermal energy to the working fluid, and then the cooled secondary fluid may be provided via the pump 424 to the thermal energy storage medium reservoir 420 to decrease the temperature of the thermal energy storage medium reservoir 420. The secondary heat transfer fluid may be any fluid capable of exchanging heat with the thermal energy storage medium. The secondary heat transfer fluid may be selected to optimize cost, heat exchange with the thermal energy storage medium at a target temperature range, etc. The secondary heat transfer fluid may be a liquid, gas, supercritical fluid, mixture, etc. In some embodiments, the secondary heat transfer fluid may be air or water.

[0112] In some systems, a hot heat transfer fluid may flow into the top of the thermocline and exit through its bottom. This moves the thermocline (e.g., temperature boundary, temperature gradient, etc.) downward, storing thermal energy in the storage medium. During the discharge cycle, a cold fluid may enter the cold bottom of the thermocline and exit through the hot top, gaining heat from the thermocline and moving the thermocline upward.

[0113] 5-6 are flow diagrams of methods 500 and 600 associated with controlling a thermal energy storage system, according to some embodiments. Methods 500 and 600 may be performed by processing logic, which may include 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), firmware, microcode, or a combination thereof. In some embodiments, methods 500 and 600 may be performed, at least in part, by a controller, such as controller 326, controller 380, or one or more other controllers. In some embodiments, a non-transitory machine-readable storage medium stores instructions that, when executed by a processing device, cause the processing device to perform one or more of methods 500 and / or 600.

[0114] For simplicity of explanation, methods 500 and 600 are shown and described as a series of acts. However, acts according to the present disclosure may occur in various orders and / or simultaneously and with other acts not shown and described herein. Moreover, not all acts shown may be performed to implement method 500 and / or 600 in accordance with the disclosed subject matter. In addition, those skilled in the art will understand and appreciate that methods 500 and 600 may alternatively be represented as a series of interrelated states via a state diagram or events.

[0115] 5 is a flow diagram of a method 500 for operating a thermal energy storage system in a target mode, according to some embodiments. The target mode may be a charge mode, a charge cycle, a heat pump mode, an energy storage mode, a heat sink generation mode, etc. The target mode may be a discharge mode, a discharge cycle, a heat engine mode, an energy consumption mode, an environmental cooling mode, etc. Operating in a target mode may include performing operations that configure operation of the system in a different mode and changing to operating in the target mode.

[0116] At block 502, processing logic (e.g., of a controller) receives input indicating that the thermal energy storage system is to be operated in a target mode. The input may include sensor data. The input may include time / date data. The input may include an indication of a user input.

[0117] At block 504, processing logic generates a control signal. The control signal may be based on the input, the target mode, operation in the target mode, etc.

[0118] At block 506, processing logic actuates a valve of the thermal energy storage system. The valve may be an on-off valve. The valve may be a control valve. The valve may be a valve that controls the division of fluid flow among multiple flow paths. Actuating the valve may include providing a control signal to the valve. Actuating the valve may include configuring the thermal energy storage system to operate in the target mode. Actuating the valve may include configuring the thermal energy storage system to no longer operate in the second mode.

[0119] As an example, a system such as the system shown in FIG. 3A may be operated in a first mode or a second mode, a charge mode or a discharge mode, etc. Operation in a first mode may include providing working fluid to components included in the first architecture 302. Operation in a second mode may include providing working fluid to components included in the second architecture 304. To transition a system such as system 300A from discharge mode to charge mode, control signals may be generated and provided to one or more components to transition flow from the second architecture 304 to the first architecture 302. To transition system 300A from operating in discharge mode to operating in charge mode, one or more valves may be actuated to direct flow through PX 310 and compressor 322 and away from turbine 324. To transition a system such as system 300A from charge mode to discharge mode, one or more valves may be actuated to direct flow from PX 310 through turbine 324.

[0120] 3B may be operated in a first mode or a second mode, a charge mode or a discharge mode, etc. Operation in a charge mode may include one or more valves (e.g., three-way valve 328, flow control valve 330) being actuated to direct the flow of working fluid to components including PX 310. Operation in a discharge mode may include actuating one or more valves of system 300B to direct the flow of working fluid through components including turbine 324.

[0121] 6 is a flow diagram of a method 600 for operating a thermal energy storage system in a target mode, according to some embodiments. At block 610, processing logic (e.g., of a controller) receives an input indicating that the thermal energy storage system is to be operated in a target mode. The input may share one or more characteristics with the input associated with block 502 of FIG. 5.

[0122] At block 612, processing logic generates one or more control signals. The control signals may be for controlling various components of the thermal energy storage system, for example, components that operate based on an operating mode of the thermal energy storage system.

[0123] At block 614, the processing logic provides one or more control signals to one or more components of the thermal energy storage system. The one or more components may include any component that operates differently in the first mode of the thermal energy storage system than in the second mode (e.g., in the target mode, differently from other operating modes). The one or more components may include one or more valves. The flow of working fluid may be directed to different sets of components based on actuation of the one or more valves. The one or more components may include one or more pumps or compressors that can enable, disable, or change operating speed based on transition of the thermal energy transfer system to the first operating mode. The one or more components may include a motor operably coupled to the PX. The one or more components may include a pump, compressor, or other transfer device for a thermal energy storage medium (e.g., molten salt, fluidized sand, etc.), a secondary heat transfer fluid (e.g., glycol, a glycol / water mixture, air, water, etc.), or other transfer device for a secondary heat transfer medium. The one or more components are configured to cause operation of the thermal energy storage system in the first mode in response to receiving the one or more control signals.

[0124] As an example, a system such as the system shown in FIG. 3C may be operated in a first mode or a second mode, a charge mode or a discharge mode, etc. If the system determines to operate in charge mode, one or more valves (e.g., temperature modulation valve 348, three-way valve 346, etc.) may be actuated. If the system determines to operate in charge mode, fluid flow may be directed away from cooling coil 344 by providing a control signal to three-way valve 346. If the system determines to operate in charge mode, fluid flow may be directed through storage medium 342 by actuation of temperature modulation valve 348. If the system determines to operate in charge mode, other components may be provided with control signals, such as pump 340, compressor 322, motor of PX 310, HP booster 385, LP booster 314, flash gas valve 320, fan 350, etc. If the system determines to operate in discharge mode, temperature modulation valve 348 may be provided with one or more control signals to mix fluids of different temperatures to achieve target performance. The three-way valve 346 may be actuated to provide fluid flow to the cooling coil 344. When the system determines to operate in a discharge mode, the fan 350 may be provided with one or more control signals to enable air flow through the cooling coil 344.

[0125] 7 is a block diagram illustrating a computer system 700 according to certain embodiments. In some embodiments, the computer system 700 is a client device. In some embodiments, the computer system 700 is a controller device (e.g., a server, controller 326 of FIG. 3B, controller 380 of FIG. 3C).

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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. According to embodiments described herein, computer system 700 may be a controller, and signal generating device 720 may be utilized to deliver control signals to components of the thermal energy storage system.

[0130] 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 encoding any one or more of the methods or functions described herein to implement the methods described herein. For example, the methods of the functions described in connection with FIGS. 5-6 may be stored as instructions 726.

[0131] 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.

[0132] 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 can store or encode 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.

[0133] 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.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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 pressure exchanger (PX) configured to receive a first fluid, receive a second fluid, and exchange pressure between the first fluid and the second fluid; a first heat exchanger configured to provide the first fluid to the PX; a second heat exchanger configured to receive the first fluid from the PX; a compressor configured to compress at least a portion of the first fluid discharged from the second heat exchanger; and an electrical energy generating device configured to convert energy of the first fluid discharged by the first heat exchanger into electrical energy; a first valve; and a processing device operably coupled to the first valve, the processing device comprising: In response to determining that the system is to be operated in a first mode, causing the first valve to provide fluid flow to the PX, the first heat exchanger, the second heat exchanger, and the compressor; and A system configured to cause the first valve to provide fluid flow to the first heat exchanger, the second heat exchanger, and the electrical energy generation device in response to determining that the system is to be operated in a second mode.

2. The system of claim 1 , further comprising a thermal energy storage medium in thermal communication with the first heat exchanger or the second heat exchanger.

3. The thermal energy storage medium is molten salt, sand, natural or artificial rock, silicon, aluminum, a phase change material, or eutectic material, The system of claim 2 , comprising one or more of:

4. The system comprises: a first reservoir containing a first portion of the thermal energy storage medium at a first temperature; a second reservoir containing a second portion of the thermal energy storage medium at a second temperature lower than the first temperature; 4. The system of claim 3, further comprising: a transfer system configured to transfer the second portion of the thermal energy storage medium from the second reservoir to the first reservoir, wherein the thermal energy storage medium is in thermal communication with the first heat exchanger while the second portion of the thermal energy storage medium is transferred via the transfer system.

5. The system comprises: a reservoir containing the thermal energy storage medium; 4. The system of claim 3, further comprising a fluid transfer system including a third fluid, the fluid transfer system configured to transfer heat between the first heat exchanger and the reservoir via the third fluid.

6. The thermal energy storage medium is carbon dioxide, Water, or phase change materials, The system of claim 2 , comprising one or more of:

7. The system comprises: a first reservoir containing a first portion of the thermal energy storage medium at a first temperature; a second reservoir containing a second portion of the thermal energy storage medium at a second temperature lower than the first temperature; 7. The system of claim 6, further comprising: a transfer system configured to transfer the first portion of the thermal energy storage medium from the first reservoir to the second reservoir, wherein the thermal energy storage medium is in thermal communication with the second heat exchanger while the first portion of the thermal energy storage medium is transferred via the transfer system.

8. the system is adapted to operate as a heat pump in the first mode; and The system of claim 1 , wherein the system is adapted to operate as a heat engine in the second mode.

9. 1. A system comprising: a pressure exchanger (PX) configured to receive a first fluid, receive a second fluid, and exchange pressure between the first fluid and the second fluid; a heat exchanger configured to receive the first fluid from the PX and to exchange heat between the first fluid and a third fluid; a heat storage medium in thermal communication with the third fluid; a cooling coil configured to exchange thermal energy between the third fluid and an environment proximate to the cooling coil; a pump configured to circulate the third fluid between the thermal storage medium, the cooling coil, and the heat exchanger.

10. 10. The system of claim 9, further comprising a gas cooler in thermal communication with the first fluid, the system being configured to transfer heat from the thermal storage medium to an environment proximate to the gas cooler when operated in a first mode.

11. The system of claim 9 , wherein the thermal storage medium comprises a reservoir of water.

12. 10. The system of claim 9, further comprising a temperature sensor, the system being configured to selectively operate the system in a first mode including operation of the PX or a second mode including operation of the cooling coil based on data generated by the temperature sensor.

13. 13. The system of claim 12, wherein operating in the first mode includes actuating a valve to provide flow of the third fluid that bypasses the cooling coil.

14. 10. The system of claim 9, further comprising a temperature modulating valve, and wherein operation in the second mode includes actuation of the temperature modulating valve to determine a first portion of the third fluid that exchanges thermal energy with the thermal storage medium.

15. 10. The system of claim 9, wherein operation of the system in a first mode includes a charge cycle that reduces the temperature of the thermal storage medium, and operation of the system in a second mode includes a discharge cycle that transfers heat from the environment proximate the cooling coil to the thermal storage medium.

16. The system of claim 9 , wherein the third fluid comprises a water-glycol mixture.

17. 1. A system comprising: a pressure exchanger (PX) configured to receive a first fluid, receive a second fluid, and exchange pressure between the first fluid and the second fluid; a first heat exchanger configured to provide the first fluid to the PX, the first heat exchanger being in thermal communication with a heat storage medium; a second heat exchanger configured to receive the first fluid from the PX, the second heat exchanger being in thermal communication with a heat source; a heat sink in thermal communication with the heat storage medium; a processing device configured to provide control signals that cause the system to operate in a first mode or a second mode.

18. 18. The system of claim 17, wherein operation in the first mode includes a charge cycle that transfers heat from the heat source to the thermal storage medium, and operation in the second mode includes a discharge cycle that transfers heat from the thermal storage medium to the heat sink.

19. The system of claim 17 , wherein the thermal storage medium comprises a phase change thermal storage medium.

20. 20. The system of claim 17, wherein the operation in the second mode includes circulating a heat transfer fluid to transfer heat from the thermal storage medium to the heat sink.

Images