Annular plate-fin heat exchanger

A heat exchanger comprising:

• an exhaust shell;
• an annular core contained within the exhaust shell, the annular core comprising:
• a first end;
• a second end that is axially opposite to the first end;
• an outer diameter defining an outer surface;
• an inner diameter defining an inner surface;
• a first plurality of fins extending in a first direction between the inner diameter and the outer diameter in a first set of layers, the first plurality of fins further comprising:
• a first inlet;
• and
• a first outlet fluidly connected to the first inlet;
• a second plurality of fins extending in a second direction between the inner diameter and the outer diameter in a second set of layers, the second plurality of fins further comprising:
• a first inlet manifold comprising:
• a second inlet, wherein the second inlet branches into a first set of tubes that connect to the second set of layers at a first region;
• and
• a first outlet manifold fluidly connected to the first inlet manifold, the first outlet manifold comprising:
• a second outlet, wherein the second outlet branches into a second set of tubes that connect to the second set of layers at a second region;
• and
• a plurality of plates separating the first set of layers and the second set of layers.