Pressure equilibrated thermal insulation gap

A thermal structure for management of thermal energy, the thermal structure comprising:

• a first wall structure defining a first cavity;
• a second wall structure defining a second cavity, the second cavity in fluid communication with the first cavity;
• and
• a barrier cavity defined at least in-part by the first wall structure and the second wall structure, wherein the barrier cavity is disposed between the first cavity and the second cavity and comprises a pressurized barrier fluid therein or is configured to receive the pressurized barrier fluid during operation of the thermal structure;
• wherein the first cavity and the second cavity are configured to receive a flow of a working fluid therethrough, wherein the barrier cavity is configured to receive a portion of the working fluid from one of the first cavity or the second cavity as a substantially static barrier fluid.