Abstract: A system including: a pumped-heat energy storage system (“PHES system”), wherein the PHES system is operable in a charge mode to convert electricity into stored thermal energy, wherein the PHES system comprises a working fluid path circulating a working fluid through, in sequence, at least a compressor system, a hot-side heat exchanger system, a turbine system, a cold-side heat exchanger system, and back to the compressor system; and (ii) a fluid path directing a hot fluid from a heat source external to the PHES system through a reheater, wherein a portion of the working fluid path through the turbine system comprises circulating the working fluid through a first turbine, the reheater, and a second turbine, and wherein the working fluid thermally contacts the hot fluid in the reheater, thereby transferring heat from the hot fluid to the working fluid.

Abstract: The present disclosure provides pumped thermal energy storage systems that can be used to store electrical energy. A pumped thermal energy storage system of the present disclosure can store energy by operating as a heat pump or refrigerator, whereby net work input can be used to transfer heat from the cold side to the hot side. A working fluid of the system is capable of efficient heat exchange with heat storage fluids on a hot side of the system and on a cold side of the system. The system can extract energy by operating as a heat engine transferring heat from the hot side to the cold side, which can result in net work output. Systems of the present disclosure can employ solar heating for improved storage efficiency.

Abstract: Solid-state thermoclines with internal baffle structures are used in place of heat exchangers in a closed thermodynamic cycle power generation or energy storage system, such as a closed Brayton cycle system. The baffles limit the conductive and/or radiative transfer of heat between a solid thermal medium within different zones defined by the baffle structures.

Abstract: Systems and methods for variable pressure inventory control of a closed thermodynamic cycle power generation system or energy storage system, such as a reversible Brayton cycle system, with at least a high pressure tank and an intermediate pressure tank are disclosed. Operational parameters of the system such as working fluid pressure, turbine torque, turbine RPM, generator torque, generator RPM, and current, voltage, phase, frequency, and/or quantity of electrical power generated and/or distributed by the generator may be the basis for controlling a quantity of working fluid that circulates through a closed cycle fluid path of the system.

Abstract: Disclosed are systems and methods for pump control of a closed thermodynamic cycle system, such as a Brayton cycle. Operational parameters such as working fluid temperature, thermal fluid temperature, stream pressure, and power generation may be the basis for controlling a thermal fluid pump rate.

Abstract: Systems and methods relating to use of external air for inventory control of a closed thermodynamic cycle system or energy storage system, such as a reversible Brayton cycle system, are disclosed. A method may involve, in a closed cycle system operating in a power generation mode, circulating a working fluid may through a closed cycle fluid path. The closed cycle fluid path may include a high pressure leg and a low pressure leg. The method may further involve in response to a demand for increased power generation, compressing and dehumidifying environmental air. And the method may involve injecting the compressed and dehumidified environmental air into the low pressure leg.

Abstract: Efficient energy storage is provided by using a working fluid flowing in a closed cycle including a ganged compressor and turbine, and capable of efficient heat exchange with heat storage fluids on a hot side of the system and on a cold side of the system. This system can operate as a heat engine by transferring heat from the hot side to the cold side to mechanically drive the turbine. The system can also operate as a refrigerator by mechanically driving the compressor to transfer heat from the cold side to the hot side. Heat exchange between the working fluid of the system and the heat storage fluids occurs in counter-flow heat exchangers. In a preferred approach, molten salt is the hot side heat storage fluid and water is the cold side heat storage fluid.

Abstract: Extra heat in a closed cycle power generation system, such as a reversible closed Brayton cycle system, may be dissipated between discharge and charge cycles. An extra cooling heat exchanger may be added on the discharge cycle and disposed between a cold side heat exchanger and a compressor inlet. Additionally or alternatively, a cold thermal storage medium passing through the cold side heat exchanger may be allowed to heat up to a higher temperature during the discharge cycle than is needed on input to the charge cycle and the excess heat then dissipated to the atmosphere.

Abstract: A power generation system comprising a shared hot side thermal store, a shared cold side thermal store, a plurality of power subunits, and an electrical bus is disclosed. Each of the power subunits may connected or isolated from the shared hot side thermal store and/or the shared cold side thermal store.

Abstract: Systems and methods relating to variable pressure turbines are disclosed. A power generation system may include a closed cycle system configured to generate power, a combustor, and a control system. The closed cycle system may include a working fluid circulating in a closed cycle path. The combustor may provide thermal energy to the working fluid. Further, the control system may be configured to determine to increase an amount of power generated by the closed cycle system, and in response to the determination to increase the amount of power generated by the closed cycle system, cause an increase in pressure of the working fluid in the closed cycle path.

Abstract: The present disclosure provides pumped thermal energy storage systems that can be used to store electrical energy. A pumped thermal energy storage system of the present disclosure can store energy by operating as a heat pump or refrigerator, whereby net work input can be used to transfer heat from the cold side to the hot side. A working fluid of the system is capable of efficient heat exchange with heat storage fluids on a hot side of the system and on a cold side of the system. The system can extract energy by operating as a heat engine transferring heat from the hot side to the cold side, which can result in net work output. Systems of the present disclosure can employ solar heating for improved storage efficiency.

Abstract: In the present disclosure, an example method is provided. The example method may comprise operating a pumped thermal system in a charging cycle at a first compression ratio, wherein the pumped thermal system comprises a working fluid circulating through, in sequence, a compressor system, a hot side heat exchanger, a turbine system, and a cold side heat exchanger, wherein the working fluid is in thermal contact with a hot thermal storage (“HTS”) medium in the hot side heat exchanger and the working fluid is in thermal contact with a cold thermal storage (“CTS”) medium in the cold side heat exchanger. The example method may also comprise operating the pumped thermal system in a discharging cycle at a second compression ratio different than the first compression ratio.

Abstract: Systems and methods for variable pressure inventory control of a closed thermodynamic cycle power generation system or energy storage system, such as a reversible Brayton cycle system, with at least a high pressure tank and an intermediate pressure tank are disclosed. Operational parameters of the system such as working fluid pressure, turbine torque, turbine RPM, generator torque, generator RPM, and current, voltage, phase, frequency, and/or quantity of electrical power generated and/or distributed by the generator may be the basis for controlling a quantity of working fluid that circulates through a closed cycle fluid path of the system.

Abstract: The present disclosure provides pumped thermal energy storage systems that can be used to store electrical energy. A pumped thermal energy storage system of the present disclosure can store energy by operating as a heat pump or refrigerator, whereby net work input can be used to transfer heat from the cold side to the hot side. A working fluid of the system is capable of efficient heat exchange with heat storage fluids on a hot side of the system and on a cold side of the system. The system can extract energy by operating as a heat engine transferring heat from the hot side to the cold side, which can result in net work output. Systems of the present disclosure can employ solar heating for improved storage efficiency.

Abstract: A power generation system comprising a shared hot side thermal store, a shared cold side thermal store, a plurality of power subunits, and an electrical bus is disclosed. Each of the power subunits may connected or isolated from the shared hot side thermal store and/or the shared cold side thermal store.

Abstract: An example method may comprise providing a composite pumped thermal system having a plurality of subunits, each configured for operation in a thermal storage mode and a power generation mode; operating the system in power output mode with a power output level at an intermediate output level between 0% and 100% of a maximum output level of the system; reducing the power output level to 0% of the maximum output level by reducing a power output of a first subunit operating in a power generation mode; and at 0% of the maximum output level, wherein a power input level of the system is also at 0% of a maximum input level of the system, increasing the power input level to an intermediate input level between 0% and 100% of the maximum input level by increasing a power input of a second subunit operating in a thermal storage mode.

Abstract: In an example, a system configured to operate in a heat pump mode and heat engine mode is disclosed. The system may comprise a first working fluid path, first hot thermal storage (HTS) fluid path, and first cold thermal storage (CTS) fluid path for operation in the heat pump mode. The first working fluid path may be configured to circulate the working fluid through, in sequence, a first compressor, first hot side heat exchanger, first turbine, first cold side heat exchanger, and back to the first compressor. The system may also comprise a second working fluid path, second HTS fluid path, and second CTS fluid path for operation in the heat engine mode. The second working fluid path may be configured to circulate the working fluid through, in sequence, a second compressor, second hot side heat exchanger, second turbine, second cold side heat exchanger, and back to the second compressor.

Abstract: The present disclosure provides pumped thermal energy storage systems that can be used to store electrical energy. A pumped thermal energy storage system of the present disclosure can store energy by operating as a heat pump or refrigerator, whereby net work input can be used to transfer heat from the cold side to the hot side. A working fluid of the system is capable of efficient heat exchange with heat storage fluids on a hot side of the system and on a cold side of the system. The system can extract energy by operating as a heat engine transferring heat from the hot side to the cold side, which can result in net work output. Systems of the present disclosure can employ solar heating for improved storage efficiency.

Abstract: The present disclosure provides pumped thermal energy storage systems that can be used to store electrical energy. A pumped thermal energy storage system of the present disclosure can store energy by operating as a heat pump or refrigerator, whereby net work input can be used to transfer heat from the cold side to the hot side. A working fluid of the system is capable of efficient heat exchange with heat storage fluids on a hot side of the system and on a cold side of the system. The system can extract energy by operating as a heat engine transferring heat from the hot side to the cold side, which can result in net work output. Systems of the present disclosure can employ solar heating for improved storage efficiency.

Abstract: Thermocline arrays comprising a plurality of pressure vessels that are in used in place of heat exchangers in a closed thermodynamic cycle system, such as a closed Brayton cycle power generation or energy storage system. Each pressure vessel is configurable to be connected to the working fluid stream or isolated from the working fluid stream.