Thermal energy storage system

A method for storing and retrieving energy in respective charging and discharging operational modes, comprising:

• providing a system that comprises:
• at least one hot heat transfer liquid (HTL) reservoir containing hot HTL;
• at least one two-phase turbine and at least one two-phase compressor configured for compressing compressor HTL, being the same or different than the hot HTL of the hot reservoir;
• wherein the at least one hot HTL reservoir is selectively (i) fluidically connectable to the at least one two-phase turbine in discharging operational mode or (ii) fluidically connectable or thermally couplable to the at least one two phase compressor in charging operational mode for (1) feeding hot HTL to the respective turbine in the discharging mode or for (2) either heat exchanging between the compressor HTL or a compressor HTL reservoir and the HTL of the hot reservoir, when the compressor HTL and the hot HTL are different and when the compressor HTL reservoir and the hot HTL reservoir are different, or feeding hot HTL to the at least one compressor, when the compressor HTL and the hot HTL are the same and the compressor HTL reservoir and the hot HTL reservoir are the same, in the charging mode;
• at least one condenser in fluid communication with the turbine for receiving and condensing a working fluid (WF) coming from the turbine;
• at least one evaporator in fluid communication with the at least one compressor for receiving and evaporating WF coming from the at least one compressor, the at least one evaporator, being same or different element than the at least one condenser;
• the discharging mode defining a first flow path of the WF and the charging mode defines a second flow path of the WF;
• and
• wherein in the discharging mode, the method comprising
• coupling the hot HTL reservoir to the at least one two-phase turbine,
• causing the WF to flow in the first flow path from the at least one condenser to one or more nozzles within the at least one turbine, to thereby mix the WF with the HTL to form a HTL/WF mixture in said one or more nozzles, in which the WF undergoes a quasi-isothermal expansion, causing acceleration of the HTL/WF mixture and discharge of the mixture through the one or more nozzles while reducing temperature of the HTL, thereby inducing rotation of the turbine upon discharge of fluid therefrom,
• receiving the HTL/WF mixture discharged out of the one or more nozzles in at least one first separation zone for separating the WF from the HTL,
• recycling back the HTL to said at least one hot reservoir or to said one or more nozzles,
• causing the separated WF to flow into and be received in the condenser to undergo condensation therein, and
• causing the condensed WF discharged from the at least one condenser to flow back to the turbine;
• wherein in the charging mode the method comprising fluidically connecting or thermally coupling the at least one hot HTL reservoir to at least one two phase compressor and causing the WF to flow in the second flow path.

A system for storing and retrieving energy in respective charging and discharging operational modes, comprising:

• at least one hot heat transfer liquid (HTL) reservoir containing hot HTL;
• at least one two-phase turbine and at least one two-phase compressor configured for compressing compressor HTL being the same or different than the hot HTL;
• the at least one hot HTL reservoir is (i) fluidically connected to the at least one two-phase turbine in discharging operational mode or (ii) fluidically connected or thermally coupled to the at least one two phase compressor in charging operational mode, for (1) feeding hot HTL to the respective turbine in the discharging mode or for (2) either heat exchanging between the compressor HTL and the hot HTL;
• at least one condenser in fluid communication with the turbine for receiving and condensing a working fluid (WF) coming from the turbine;
• at least one evaporator in fluid communication with the at least one compressor for receiving and evaporating WF coming from the at least one compressor, the at least one evaporator, being same or different element than the at least one condenser;
• the discharging mode defines a first flow path of the WF and the charging mode defines a second flow path of the WF and the system is switchable between the discharging operational mode and the charging operational mode such that switching between the discharging operational mode and the charging operational mode switches the flow of the WF between the first flow path and the second flow path, respectively;
• and
• wherein in a discharging mode, the at least one hot HTL reservoir is fluidically connected to the at least one two-phase turbine, and the WF flows in the first flow path from the at least one first condenser to one or more nozzles within the at least one turbine, the nozzles being configured to induce rotation of the turbine upon discharge of fluid therefrom, to thereby mix the WF with the HTL to form a HTL/WF mixture in said one or more nozzles, in which the WF undergoes a quasi-isothermal expansion, causing acceleration of the HTL/WF mixture and discharge of the mixture through the one or more nozzles while reducing temperature of the HTL, the HTL/WF mixture discharged out of the one or more nozzles being received in at least one first separation zone configured to separate the WF from the HTL, the HTL being recycled back to said at least one hot reservoir or to said one or more nozzles and the separated WF flowing into and received in the condenser to undergo condensation therein, the condensed WF discharged from the at least one condenser streamed back to the turbine;
• and
• wherein in the charging mode, the at least one hot HTL reservoir is fluidically connected or thermally coupled to the at least one two phase compressor, and the WF flows in the second flow path and the at least one compressor is configured to form a compressor HTL/WF mixture and quasi-isothermally compress the WF in the mixture along a compressor flow path and to thereby heat the compressor HTL, the compressor HTL being cycled back to a reservoir, being the same or different the hot HTL reservoir or to the at least one compressor, the compressed WF being discharged from the at least one compressor flows to be received in the evaporator to undergo evaporation, the evaporated WF discharged from the at least one evaporator being back to the at least one compressor.