Reverse header design for thermal cycle

A header tank for a heat exchanger comprising:

• a casing having a hollow interior;
• and
• a header coupled to the casing, the header comprising a header wall defining a tube receiving portion having a plurality of tube openings formed therethrough and spaced apart in a longitudinal direction of the header, the tube receiving portion including a planar portion and an adjacent offset portion, the planar portion disposed on a first plane and the offset portion having a variable distance from the first plane as the offset portion extends away from the planar portion with respect to the longitudinal direction of the header, wherein the plurality of tube openings includes a plurality of first tube openings and a plurality of second tube openings, wherein each of the plurality of first tube openings is formed through one of a plurality of first tube projections projecting from the planar portion and wherein each of the plurality of second tube openings is formed through one of a plurality of second tube projections projecting from the offset portion, wherein each of the plurality of first tube projections projects in a first direction and at least one of the plurality of second tube projections projects in a second direction opposite the first direction, wherein the at least one of the plurality of second tube projections projecting in the second direction results in the tubes received therein having a shorter length than the tubes received in the plurality of first tube projections projecting in the first direction, thereby minimizing a thermal expansion or contraction of the tubes received in the at least one of the plurality of second tube projections projecting in the second direction to minimize a stress between the tubes and the plurality of second tube projections.

A heat exchanger comprising:

• a first header tank including a hollow first casing and a first header, the first header comprising a header wall defining a tube receiving portion having a plurality of tube openings formed therethrough and spaced in a longitudinal direction of the first header, the tube receiving portion including a planar portion and an adjacent offset portion, the planar portion disposed on a first plane and the offset portion having a variable distance from the first plane as the offset portion extends away from the planar portion with respect to the longitudinal direction of the first header;
• a second header tank including a hollow second casing and a second header;
• and
• a plurality of heat exchanger tubes extending between the first header tank and the second header tank, wherein the plurality of tube openings includes a plurality of first tube openings and a plurality of second tube openings, wherein each of the plurality of first tube openings is formed through one of a plurality of first tube projections projecting from the planar portion configured to receive a first end of one of the heat exchanger tubes and wherein each of the plurality of second tube openings is formed through one of a plurality of second tube projections projecting from the offset portion configured to receive a second end of one of the heat exchanger tubes, wherein each of the plurality of first tube projections projects in a first direction and at least one of the plurality of second tube projections projects in a second direction opposite the first direction, wherein the at least one of the plurality of second tube projections projecting in the second direction results in the heat exchanger tubes received therein having a shorter length than the heat exchanger tubes received in the plurality of first tube projections projecting in the first direction, thereby minimizing a thermal expansion or contraction of the tubes received in the at least one of the plurality of second tube projections projecting in the second direction to minimize a stress between the tubes and the plurality of second tube projections.