Monolithic bicontinuous labyrinth structures and methods for their manufacture

A heat exchanger, comprising:

• a core comprising a single piece continuous boundary having a first surface defining a first labyrinth, and an opposing second surface defining a second labyrinth;
• a first inlet manifold connected to the first labyrinth and configured to supply a first fluid to the first labyrinth;
• and
• a second inlet manifold connected to the second labyrinth and configured to supply a second fluid to the second labyrinth;
• wherein:
• the core comprises a plurality of three dimensional unit cell structures replicated in three orthogonal spatial dimensions;
• the first inlet manifold defines a first inlet interface with the first labyrinth, and the second inlet manifold defines a second inlet interface with the second labyrinth;
• the first inlet interface comprises a first inlet finning structure configured to selectively shunt the first fluid from the second labyrinth and selectively direct the first fluid into the first labyrinth;
• and
• the second inlet interface comprises a second inlet finning structure configured to selectively shunt the second fluid from the first labyrinth and selectively direct the second fluid into the second labyrinth.