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 network 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 network output. Systems of the present disclosure can employ solar heating for improved storage efficiency.

A method of operating a thermal energy storage system comprises operating a pump to circulate a heat transfer fluid from cold storage through a heating system to hot storage, supplying electric power from an electric power grid external to the thermal energy storage system to power an electric heater in the heating system that heats the heat transfer fluid as it circulates through the heating system to hot storage, regulating a flow rate of the heat transfer fluid through the heating system so that the heat transfer fluid enters hot storage at a specified temperature, and regulating the supplying of electric power from the electric power grid to the electric heater to balance supply of and demand for power on the electric power grid and maintain a frequency, a voltage, or a frequency and a voltage of electric power on the electric power grid at specified values.

There is provided a thermal energy storage system, comprising at least two thermal storage masses, wherein an inner thermal storage mass (48) is contained within an outer thermal storage mass (49). A pump or compressor (42) forces a compressible fluid around the system. A first storage mass heat exchanger (50) has a first side in fluid communication with the pump or compressor (42), and a second side in contact with the outer thermal storage mass (49). A second storage mass heat exchanger (51) has a first side in fluid communication with the first side of the first storage mass heat exchanger (50), and a second side in contact with the inner thermal storage mass (48). A turbine (43) has a turbine inlet in fluid communication with the first side of the second storage mass heat exchanger (51), and a turbine outlet. An electrical generator is driven by the turbine (43). The system further comprises a thermal store (52) containing a thermal store medium. At least one thermal input heat exchanger (55) is located in the thermal store (52), the at least one thermal input heat exchanger having a first side adapted to receive heat from the outer thermal storage mass (49), and a second side in contact with the thermal store medium. At least one thermal output heat exchanger (53) is also located in the thermal store (52), the at least one thermal output heat exchanger having a first side in fluid communication with a hot water and/or heating supply, and a second side in contact with the thermal store medium.

A power generation system for a nuclear reactor includes an externally-heated turbine engine, a reactor heat exchanger, and a heat recuperating system. The externally-heated turbine engine produces compressed air that is heated by the reactor heat exchanger. The heat recuperating system includes a heat exchanger thermally connected to the externally-heated turbine engine to transfer heat to the compressed air to supplement the reactor heat exchanger.

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.

A dispatchable storage combined cycle power plant comprises a topping cycle that combusts fuel to generate electricity and produce hot exhaust gases, a steam power system, a heat source other than the topping cycle, and a thermal energy storage system. Heat from the heat source, from the thermal energy storage system, or from the heat source and the thermal energy storage system is used to generate steam in the steam power system. Heat from the topping cycle may be used in series with or in parallel with the thermal energy storage system and/or the heat source to generate the steam, and additionally to super heat the steam.

An organic Rankine cycle system (100, 110, 120) with direct exchange and in cascade comprising a high temperature organic Rankine cycle (10) which carries out the direct heat exchange with a hot source (H) and a low temperature organic Rankine cycle (10′) in thermal communication with the high temperature cycle (10). The organic Rankine cycle system (100, 110, 120) is configured in a way that the thermal communication between the cycles (10, 10′) takes place through at least one heat exchanger (3) configured to use at least the condensation heat of the high temperature cycle to vaporize and/or preheat the working fluid of the low temperature organic Rankine cycle fluid and through a heat exchanger (4) configured to operate as working fluid sub-cooler for the high temperature organic Rankine cycle (10) and as a working fluid preheater for the low temperature organic Rankine cycle (10′).

Systems and processes provide for a thermal process to transform sludge (and a variety of other natural waste materials) into electricity. Dewatered sludge and other materials containing a high amount of latent energy are dried into a powdered biofuel using a drying gas produced in the system. The drying gas is recirculated and is heated by the biofuel produced in the system, waste heat (from turbines or internal combustion engines), gas (including natural gas or digester gas) and/or oil. The biofuel is combusted in a boiler system that utilizes a burner operable to burn biofuel and produce heat utilized in a series of heat exchangers that heat the recirculating drying air and steam that powers the turbines for electricity production.

A dispatchable storage combined cycle power plant comprises a combustion turbine generator, a steam power system, a heat source other than the combustion turbine generator, and a thermal energy storage system. Heat from the heat source, from the thermal energy storage system, or from the heat source and the thermal energy storage system is used to generate steam in the steam power system. Heat from the combustion turbine may be used in series with or in parallel with the thermal energy storage system and/or the heat source to generate the steam, and additionally to super heat the steam.

A Waste-to-Energy plant comprising: an incineration chamber in which waste is combusted generating flue gas; an economizer heating feedwater using heat from the flue gas; an evaporator producing steam from the heated feedwater using heat from the flue gas; a steam drum receiving heated feedwater from the economizer and supplying heated feedwater, the steam drum receiving steam from the evaporator and supplying steam; and a superheater receiving and heating steam from the steam drum to a superheated steam using heat from the flue gas; the incineration chamber comprising a first PCM-wall and a second PCM-wall each comprising a plurality of pipes and a layer of PCM provided between the pipes and the incineration chamber, the pipes in the first PCM-wall receiving heated feedwater from the steam drum and producing additional steam therein and the pipes of the second PCM-wall additionally heating steam therein using radiant heat from the incineration chamber.