Abstract: A system for producing and storing electrical energy includes a thermally insulated chamber containing a first circuitry in which circulates a first working fluid, a hot source, a cold source, wherein the hot source is composed of a pure water ice slurry at 0° C., the cold source is composed of an ice slurry with a temperature lower than or equal to ?40° C. and the system for producing/storing electrical energy further includes a second circuitry of working fluid for circulating a second working fluid between the hot source and a thermostat, wherein the second working fluid is circulated between said thermostat and the hot source by an auxiliary expansion valve and an auxiliary compressor.