Dual stirling cycle liquid air battery

A recovery engine comprising:

• a cryocooler to cool a tip of a cold head to cryogenic temperatures, the cryocooler further comprising:
• a heat sink to reject heat from the cryocooler, and
• the cold head that protrudes into a dewar through a cryocooler cavity, the cold head to condense ambient air to create liquified air in the dewar;
• the dewar to hold the liquified air at low temperatures, the dewar having the cryocooler cavity and a Stirling cavity;
• and
• a Stirling engine to drive an electric generator, the Stirling engine further comprising:
• a cold finger protruding into the dewar through the Stirling cavity, the cold finger to extend a cold side of the Stirling engine into the liquified air of the dewar,
• a Stirling heat sink at ambient temperature to form a hot side of the Stirling engine, the hot side and the cold side of the Stirling engine causing a temperature difference that drives the electric generator, and
• the electric generator to generate output electricity.