Annular or ring shaped fuel cell unit

A fuel cell unit comprising:

• an annular array of fuel cell stacks surrounding a central axis, with each of the fuel cell stacks having a stacking direction extending parallel to the central axis, wherein each of the stacks has a rectangular cross section;
• an annular cathode feed manifold having a first annular portion positioned radially inward from the fuel cell stacks, a radial portion extending radially outward from the first annular portion in a generally symmetric 360 degree pattern, and a second annular portion extending from the radial portion generally parallel to the first annular portion and surrounding the annular array of fuel cell stacks to deliver a cathode feed flow thereto;
• a plurality of baffles extending parallel to the central axis, each of the baffles located between an adjacent pair of the fuel cell stacks to direct a cathode feed flow from the annular cathode feed manifold and radially inwardly through the adjacent pair;
• an annular cathode exhaust manifold surrounded by the annular array of fuel cell stacks to receive a cathode exhaust flow therefrom;
• and
• a radial cathode exhaust flow passage located underneath the ring-shaped structure and extending from the annular cathode exhaust manifold in a generally symmetric 360 degree pattern to a location radially outward of the annular cathode feed manifold.