TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Assembly: The beams are shaped in such a manner that they are of greater width in a center portion and are narrower at an end near a perimeter of the spring element such that the spring element as a whole is subjected to a substantially constant stress when deformed. The fastening members of the side clamp are received into the grooves of the spring elements such that the overall dimension in a Z-direction of the fuel cell system is maintained and is not substantially increased. The spring elements are substantially comprised of at least one of high strength stainless steel, carbon steel, titanium, or other metal alloys. The single sheet of metal is generally rectangular and sized to encompass an outer surface of the direct oxidation fuel cell system. Preferred Fuel System: A direct oxidation fuel cell system comprises (A) a monopolar stack configuration fuel cell including (i) pair of membrane electrode assemblies, each having an anode aspect and a cathode aspect, (ii) an anode current collector, (iii) an enthalpy exchange assembly having a hot side element, the hot side element having ribs formed an outer surface thereof facing the ambient environment; a cold side element, the cold side element acting as a current collector and also including a heat spreader plate for collecting and directing heat to other parts of the fuel cell system, and an enthalpy exchange membrane sandwiched between the hot side element and the cold side element, and (B) a spring assembly comprising (i) a pair of spring elements, each spring element being a flat spring having a curved cross section when undeformed and being substantially flat when deformed, each the spring element being comprised of a single sheet of metal having spaced parallel beams, the beams being sized to be received in a nesting configuration within the ribs of the outer surface of the hot side elements of the fuel cell assembly, each spring element also having one or more grooves formed in it adapted to receive a fastening member of a side clamp, the spring elements being a top and bottom spring element, respectively, and (ii) a pair of side clamps, each side clamp having a body portion adapted to be received over two opposite sides of the direct oxidation fuel cell system, each the side clamp having at least one fastening member extending generally perpendicular to a body portion of the side clamp, and the fastening member having a curved portion that engages a groove in the spring element where the fastening members of the side clamps form a self-locking mechanism to compress the top and bottom spring elements in a substantially flat shape over the hot side of the enthalpy exchanger at each of a top and bottom portion of the direct oxidation fuel cell system, respectively. The heat spreader plate has sufficient bending stiffness such that the plate acts as a compression plate to substantially provide adequate MEA compression. The spring elements have a free height that is substantially higher than the MEA compression such that the spring elements counteract MEA creep without significant compression reduction of the stack such that the direct oxidation fuel cell system is substantially creep tolerant. The fastening members of the side clamp are received into the grooves of the spring elements such that the overall dimension in a Z-direction of the fuel cell system is maintained and is not substantially increased. The spring elements when deformed and compressed by the side clamps provide substantially adequate compression for the enthalpy exchange membrane. The beams of the spring elements are shaped in such a manner that they are of greater width in a center portion and are narrower at an end near a perimeter of the spring element such that the spring element as a whole provides a substantially constant stress when deformed. The spring elements are substantially comprised of at least one of high strength stainless steel, carbon steel, titanium, or other metal alloys. Each of the spring elements is generally rectangular and sized to encompass an outer surface of the direct oxidation fuel cell system. A direct oxidation fuel cell system comprises (A) a direct oxidation fuel cell including (i) a membrane electrode assembly (MEA), having an anode aspect and a cathode aspect, (ii) an anode current collector, (B) an enthalpy exchange assembly disposed adjacent to the direct oxidation fuel cell, the enthalpy exchange assembly having a hot side element, the hot side element having ribs formed an outer surface thereof facing the ambient environment; a cold side element, the cold side element acting as a current collector and also including a heat spreader plate for collecting and directing heat to other parts of the fuel cell system; and an enthalpy exchange membrane sandwiched between the hot side element and the cold side element, and (C) a spring assembly comprising (i) a pair of spring elements, each spring element being a flat spring having a curved cross section when undeformed and being substantially flat when deformed, each the spring member being comprised of a single sheet of metal having spaced parallel beams, the beams of at least one of the spring elements being sized to be received in a nesting configuration within the ribs of an outer surface of the hot side element of the enthalpy exchange assembly, each spring element also having one or more grooves formed in it adapted to receive a fastening member of a side clamp, the spring elements being a top and bottom spring element, respectively, and (ii) a pair of side clamps, each side clamp having a body portion adapted to be received over two opposite sides of the direct oxidation fuel cell, each the side clamp having at least one fastening member extending generally perpendicular to a body portion of the side clamp, and the fastening member having a curved portion that engages a groove in the spring element where the fastening members of the side clamps form a self-locking mechanism to compress the top and bottom spring elements in a substantially flat shape over a top and bottom portion of the direct oxidation fuel cell system, respectively. The heat spreader plate has sufficient bending stiffness that is also acts as a MEA compression plate in the fuel cell system. At least one spring element has a free height that is substantially higher than the MEA compression, such that it counteracts MEA creep without significant compression reduction of the fuel cell system. Preferred Method: The method of securing a direct oxidation fuel cell system further comprises providing at least one heat spreader plate that also acts as a compression plate to distribute uniformly adequate MEA compression for operation of at least one direct oxidation fuel cell in the fuel cell system. The method further comprises selecting a free height for the spring elements such that the elements when deformed provide adequate compression for an enthalpy exchange assembly in at least one fuel cell in the fuel cell system. The method further comprises selecting a material for the spring elements such that the spring elements slightly deform when an associated MEA exhibits creep.