Plant and process for energy storage and method for controlling a heat carrier in a process for energy storage

A process for energy storage, comprising:

• carrying out a closed cyclic thermodynamic transformation, first in one direction in a charge configuration/phase and then in an opposite direction in a discharge configuration/phase, between a casing for the storage of a working fluid different from atmospheric air, in a gaseous phase and in pressure equilibrium with the atmosphere, and a tank for the storage of said working fluid in a liquid or supercritical phase;
• wherein, in the charge phase, the process accumulates heat and potential energy in the form of pressure and in the discharge phase generates energy, wherein
• in the charge phase, condensation of the working fluid is carried out by absorption of heat by a heat carrier, executed in a condenser/evaporator which works as a cooler/condenser, in order to store said working fluid in the liquid or supercritical phase;
• in the discharge phase, evaporation of the working fluid, executed in said condenser/evaporator which works as a heater/evaporator, is performed starting from the liquid or supercritical phase and by transfer of heat from the heat carrier;
• at least one parameter of the working fluid related to condensation and/or evaporation is actively adjusted in order to control at least one temperature of the heat carrier and to uncouple said at least one temperature of the heat carrier from an ambient temperature;
• and
• said at least one parameter of the working fluid is selected from a group comprising:
• a condenser inlet temperature;
• a condensation start temperature;
• a condensation end temperature;
• a condenser outlet temperature;
• an evaporator inlet temperature;
• an evaporation start temperature;
• an evaporation end temperature;
• and
• an evaporator outlet temperature.

A plant for energy storage, comprising:

• a working fluid other than atmospheric air;
• at least one casing configured to store the working fluid in a gaseous phase and in pressure equilibrium with the atmosphere;
• at least one tank configured to store said working fluid in a liquid or super-critical phase;
• pipes operatively interposed between the casing and the tank and connecting, directly and/or indirectly, the casing with the tank, the pipes delimiting:
• at least one charge path extended from the casing to the tank, and
• at least one discharge path extended from the tank to the casing;
• at least one expander arranged along the pipes and configured to expand the working fluid;
• at least one compressor placed along the pipes and configured to compress the working fluid;
• and
• at least one condenser/evaporator placed along the pipes, operatively coupled to the tank and comprising a heat carrier configured to transfer heat to the working fluid or to absorb heat from the working fluid, wherein
• the plant is configured to carry out a closed cyclic thermodynamic transformation with the working fluid, first in one direction in a charge configuration and then in an opposite direction in a discharge configuration, between said casing and said tank;
• in the charge configuration, the plant is configured to condense the working fluid through heat absorption by the heat carrier, executed in the condenser/evaporator which works as a cooler/condenser, and to store said working fluid in the liquid or super-critical phase;
• in the discharge configuration, the plant is configured to evaporate the working fluid starting from the liquid or super-critical phase through transfer of heat from the heat carrier, executed in said condenser/evaporator which works as a heater/evaporator;
• the plant comprises adjusting devices and a control unit operatively coupled to the adjusting devices;
• the control unit is configured and/or programmed to actively adjust at least one parameter of the working fluid related to condensation and/or evaporation through said adjusting devices, in order to control at least one temperature of the heat carrier and to uncouple said at least one temperature of the heat carrier from an ambient temperature;
• and
• said at least one parameter of the working fluid is selected from a group comprising:
• a condenser inlet temperature;
• a condensation start temperature;
• a condensation end temperature;
• a condenser outlet temperature;
• an evaporator inlet temperature;
• an evaporation start temperature;
• an evaporation end temperature;
• and
• an evaporator outlet temperature.