Dual-powertrain pumped heat energy storage with inventory control and purge

A pumped heat energy storage system, the system comprising:

• a first working fluid path arranged to circulate a working fluid through, in sequence, a charge compressor system (130), a hot-side heat exchanger (“HHX”) system (500), a recuperator heat exchanger (“RHX”) system (400), a charge turbine system (140), a cold-side heat exchanger (“CHX”) system (600), the RHX system, and back to the charge compressor system, wherein a first high-pressure leg comprises a portion of the first fluid path between an outlet of the charge compressor system and an inlet of the charge turbine system, and wherein a first low-pressure leg comprises a portion of the first fluid path between an outlet of the charge turbine system and an inlet of the charge compressor system;
• a second working fluid path arranged to circulate a working fluid through, in sequence, a generation compressor system (230), the RHX system, the HHX system, a generation turbine system (240), the RHX system, the CHX system, and back to the generation compressor system, wherein a second high-pressure leg comprises a portion of the second fluid path between an outlet of the generation compressor system and an inlet of the generation turbine system, and wherein a second low-pressure leg comprises a portion of the second fluid path between an outlet of the generation turbine system and an inlet of the generation compressor system;
• and
• an inventory control system (“ICS”) comprising:
• a high-pressure tank system (320),
• a low-pressure tank system (310),
• a first valve (322) connected between the high-pressure tank system and at least one of the first low-pressure leg and the second low-pressure leg, and
• a second valve (311) connected between the low-pressure tank system and at least one of the first high-pressure leg and the second high-pressure leg.