Thermal energy storage system with deep discharge

A thermal energy storage system configured to output stored thermal energy at a delivery temperature, including:

• a thermal storage assemblage configured to store heat generated from received energy as thermal energy;
• one or more temperature sensors;
• and
• a heat extraction system configured to:
• during a first discharge interval, partially discharge the thermal storage assemblage to reduce the temperature of the thermal storage assemblage to a first minimum temperature that is not within a deep-discharge temperature region;
• and
• based on temperature information generated by the one or more temperature sensors, initiate a deep discharge cycle of the thermal storage assemblage, during a second discharge interval, to reduce the temperature of the thermal storage assemblage to a second minimum temperature that is within the deep-discharge temperature region that is lower than the first minimum temperature;
• wherein the heat extraction system is configured to control an inlet valve for the partial discharge and for the deep discharge;
• the inlet valve is configured to open to ambient air having a bypass temperature;
• the bypass temperature is less than the delivery temperature;
• and
• the second minimum temperature is closer to the bypass temperature than to the delivery temperature.

A method of operating a thermal energy storage system, including:

• storing, by the thermal energy storage system, heat generated by one or more heater devices from received energy as thermal energy in a thermal storage assemblage;
• outputting, by the thermal energy storage system, stored thermal energy at a delivery temperature, including:
• during a first discharge interval, partially discharging the thermal storage assemblage to reduce the temperature of the thermal storage assemblage to a first minimum temperature that is not within a deep-discharge temperature region;
• and
• based on temperature information generated by one or more temperature sensors, initiating a deep discharge cycle of the thermal storage assemblage, during a second discharge interval, to reduce the temperature of the thermal storage assemblage to a second minimum temperature that is within the deep-discharge temperature region that is lower than the first minimum temperature.