A heating, ventilation, air conditioning, and refrigeration (HVACR) system includes a heating fluid circuit, a cooling fluid circuit, and a storage fluid circuit. A thermal system of the HVACR system absorbs energy from the storage fluid circuit and rejects it to the heating fluid circuit. The storage fluid circuit includes thermal storage tanks containing thermal storage material that can provide energy for heating or absorb energy for cooling depending on the state of the thermal storage material. Heating can be provided using the heating fluid circuit and the heat provided by the thermal system. Cooling can be provided using the cooling fluid circuit by absorbing energy from the conditioned space using a cooling fluid and rejecting energy from the cooling fluid to the storage fluid circuit including the thermal storage tanks. The thermal storage tanks can also have heat added to them using an air source heat pump system to provide sufficient storage for heating operations.

A method of temporarily storing thermal energy via a thermal storage subsystem in a compressed air energy storage system comprising an accumulator disposed at least 300 m underground and having an interior configured to contain compressed air at an accumulator pressure that is at least 20 bar and a gas compressor/expander subsystem in communication with the accumulator via an air flow path for conveying compressed air to the accumulator when in a charging mode and from the accumulator when in a discharging mode.

An assembly for storing thermal energy comprising a phase change material, PCM, storage vessel and at least one heat transfer fluid, HTF, receptacle, the PCM storage vessel being defined by a thermally conductive wall 108, the PCM storage vessel 100 comprising an inverted tapered portion, the inverted tapered portion having a tip portion and a base portion, the tip portion having a diameter less than the diameter of the base portion, the tip portion being arranged relatively beneath the base portion, the at least one HTF receptacle being provided adjacent to and in thermal communication with at least a portion of the PCM storage vessel, thermal communication between the PCM storage vessel and the at least one HTF receptacle occurring via the thermally conductive wall, and wherein the HTF receptacle comprises a portion for receiving thermal energy from an external thermal energy source, the said the portion being adjacent the tip portion of the inverted tapered portion.

A system and method of combining pumped hydro and thermal energy storage is disclosed that has upper and lower fluid storage reservoirs. The reservoirs are used as a pumped energy storage system in which excess electrical power is stored as gravitational potential energy by using it to transfer fluid up to the upper one. At a later time, the fluid is run back down through a turbine under the force of gravity to generate electricity. Either, or both, fluid storage regions are also used to store thermal energy transferred into the stored fluid via liquid-to-liquid heat exchangers. The stored thermal energy is later extracted out to be distributed in for use in either directly heating structures or to improve the heating efficiency of one or more heat pumps in a district heating system. The fluid may be water, or it may be any suitable high-density fluid such as drilling mud.

A heat storage device includes a heat storage, a first flow passage, a second flow passage and a flow rate regulator. The heat storage stores heat released from coolant. The first flow passage is placed in a circulation path that conducts the coolant. The heat storage is installed in the first flow passage. The second flow passage conducts the coolant and bypasses the heat storage. The flow rate regulator adjusts a flow rate ratio that is a ratio of a second flow rate of the coolant, which flows in the second flow passage, relative to a first flow rate of the coolant, which flows in the first flow passage. The flow rate regulator reduces the first flow rate when a temperature of the coolant is decreased.

An arrangement for storing energy, the arrangement comprising a heat-charging mass (4) and a heat-transfer channeling (3), the arrangement also comprising a heating member (11) adapted to heat up the heat-charging mass (4). The arrangement comprises a boiler belonging to a discarded combustion power plant and converted to a thermal energy storage (2) by at least partly filling the boiler with the heat-charging mass (4).

An energy storage system converts variable renewable electricity (VRE) to continuous heat at over 1000° C. Intermittent electrical energy heats a solid medium. Heat from the solid medium is delivered continuously on demand. An array of bricks incorporating internal radiation cavities is directly heated by thermal radiation. The cavities facilitate rapid, uniform heating via reradiation. Heat delivery via flowing gas establishes a thermocline which maintains high outlet temperature throughout discharge. Gas flows through structured pathways within the array, delivering heat which may be used for processes including calcination, hydrogen electrolysis, steam generation, and thermal power generation and cogeneration. Groups of thermal storage arrays may be controlled and operated at high temperatures without thermal runaway via deep-discharge sequencing. Forecast-based control enables continuous, year-round heat supply using current and advance information of weather and VRE availability. High-voltage DC power conversion and distribution circuitry improves the efficiency of VRE power transfer into the system.

A system including: (i) 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 in a hot thermal storage (“HTS”) medium; (ii) an electric heater in thermal contact with the hot HTS medium, wherein the electric heater is operable to heat the hot HTS medium above a temperature achievable by transferring heat from a working fluid to a warm HTS medium in a thermodynamic cycle.

The present disclosure describes heat exchangers for converting thermal energy stored in solid particles to electricity. Electro-thermal energy storage converts off-peak electricity into heat for thermal energy storage, which may be converted back to electricity, for example during peak-hour power generation. The heat exchanger for converting thermal energy stored in solid particles to electricity enables the conversion of thermal energy into electrical energy for redistribution to the grid. In some embodiments, pressurized fluidized-bed heat exchangers may achieve efficient conversion of thermal energy to electricity by providing direct contact of the solid particles with a gas stream.

The present invention provides a thermal energy storage apparatus comprising a housing which defines a hollow interior chamber, the chamber arranged in use to house graphite solids material in an inert gas atmosphere therewithin; and at least one conduit arranged to extend through the hollow interior chamber via inlet and outlet openings in the housing, the conduit being sealingly fitted to the housing at the inlet and outlet openings, and an exterior surface of the or each conduit being arranged in a close facing relationship with the graphite solids material located within the hollow interior chamber, wherein, in use, the or each conduit is arranged for conveying a flow of a fluid therethough such that in a first configuration, said flow transfers thermal energy to the graphite solid material, and in a second configuration, the graphite solid material transfers thermal energy to said flow.