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.

The present disclosure provides pumped heat energy storage systems that can be used to store and extract electrical energy. A pumped heat energy storage system of the present disclosure can store energy by operating as a heat pump, 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 also 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. Shared powertrains and reversible powertrains are disclosed to circulate the working fluid.

The invention relates to power plant with a steam water power cycle and a lignite dryer that uses steam from the steam water power cycle. The connection of the lignite dryer to the steam water power cycle includes a first extraction line and a second extraction line.

The invention relates to power plant with a steam water power cycle and a lignite dryer that uses steam from the steam water power cycle. The connection of the lignite dryer to the steam water power cycle includes a first extraction line and a second extraction line.

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.

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.

Systems and methods are provided for charging a pumped thermal energy storage (“PTES”) system. A system may include a compressor or pump configured to circulate a working fluid within a fluid circuit, wherein the working fluid enters the pump at a first pressure and exits at a second pressure; a first heat exchanger through which the working fluid circulates in use; a second heat exchanger through which the working fluid circulates in use; a third heat exchanger through which the working fluid circulates in use, a turbine positioned between the first heat exchanger and the second heat exchanger, configured to expand the working fluid to the first pressure; a high temperature reservoir connected to the first heat exchanger; a low temperature reservoir connected to the second heat exchanger, and a waste heat reservoir connected to the third heat exchanger.

Systems and methods are provided for charging a pumped thermal energy storage (“PTES”) system. A system may include a compressor or pump configured to circulate a working fluid within a fluid circuit, wherein the working fluid enters the pump at a first pressure and exits at a second pressure; a first heat exchanger through which the working fluid circulates in use; a second heat exchanger through which the working fluid circulates in use; a third heat exchanger through which the working fluid circulates in use, a turbine positioned between the first heat exchanger and the second heat exchanger, configured to expand the working fluid to the first pressure; a high temperature reservoir connected to the first heat exchanger; a low temperature reservoir connected to the second heat exchanger, and a waste heat reservoir connected to the third heat exchanger.

A method including: (i) receiving a first amount of electricity into a pumped-heat energy storage system (“PHES system”) from a power generation plant supplying a second amount of electricity to an electrical grid; (ii) operating the PHES system in a charge mode, converting at least a portion of the received first amount of electricity to stored thermal energy; and (iii) increasing a power level of the PHES system such that the first amount of electricity that the PHES system receives from the power generation plant is increased such that the second amount of electricity supplied to the electrical grid by the power generation plant is a reduced amount of electricity less than the second amount of electricity.

A subcritical pressure high-temperature steam power plant includes a combustion boiler system, steam turbine generator system, and condensate and feedwater system and wherein the conditions of steam generated in the boiler system and supplied to the steam turbine generator system are subcritical pressure and high temperature (turbine inlet temperature of 593° C. or more).