Thermal conditioning fluids for an underwater cryogenic storage vessel

A fuel system, comprising:

• a thermal conditioning module configured to
• receive a gaseous first fluid from a storage vessel, the first fluid being oxygen;
• receive a gaseous second fluid from a fuel cell, the second fluid being carbon dioxide;
• condition the gaseous first fluid from the storage vessel by absorbing heat from the gaseous second fluid to create a conditioned gaseous first fluid;
• provide a first portion of the conditioned gaseous first fluid to the fuel cell;
• provide a second portion of the conditioned gaseous first fluid back to the storage vessel;
• convert the gaseous second fluid received from the fuel cell to a liquid second fluid;
• and
• provide the liquid second fluid to the storage vessel.

A fuel system, comprising:

• a fuel cell;
• a storage vessel comprising
• a first storage tank and a second storage tank, each configured to store a first fluid to be supplied to the fuel cell, the first fluid being oxygen, and
• a storage compartment configured to store a liquid second fluid supplied by the fuel cell, the second fluid being carbon dioxide;
• and
• a thermal conditioning module configured to
• receive the first fluid from the storage vessel,
• receive a gaseous second fluid from the fuel cell,
• condition the first fluid received from the storage vessel by absorbing heat from the gaseous second fluid received from the fuel cell to create a conditioned first fluid,
• provide a first portion of the conditioned first fluid to the fuel cell from the thermal conditioning module,
• provide a second portion of the conditioned first fluid back to the storage vessel,
• convert the gaseous second fluid received from the fuel cell to the liquid second fluid, and
• provide the liquid second fluid to the storage vessel for storage in the storage compartment.