Heat exchanger

A heat exchanger comprising:

• a hollow housing;
• a plurality of flat tubes, each flat tube having an internal space and, in cross-section, larger and smaller axes perpendicular to each other, said flat tubes being stacked in a direction perpendicular to the larger axis, parallel and spaced from each other;
• first intercalary means made of a thermally conducting material and disposed within the internal spaces within said flat tubes, dividing the internal spaces of said flat tubes into a plurality of first flow channels for flow of a first liquid at a first temperature, the first flow channels extending axially in said hollow housing;
• second intercalary means made of a thermally conducting material and disposed between adjacent pairs of said flat tubes, dividing spaces between adjacent pairs of said flat tubes into a plurality of second flow channels for a second fluid, a first fluid flowing at a first temperature through the first flow channels being in thermal exchange with a second fluid flowing at a second temperature, different from the first temperature, through the second flow channels;
• an inlet/outlet header tank including an inlet/outlet header plate sealed to first ends of said flat tubes for flow of the first fluid, said inlet/outlet header plate being rigidly secured to said hollow housing;
• and
• a fluid return header tank including a header plate to which second ends of said flat tubes are sealed for returning flow of the first fluid, said header plate not being connected to said hollow housing, wherein
• said inlet/outlet header is separated into an inlet portion and an outlet portion,
• said plurality of flat tubes comprises flat tubes extending between the inlet portion of said inlet/outlet header and said fluid return header tank, and flat tubes extending between said fluid return header tank and the output portion of said inlet/outlet header,
• said hollow housing comprises an inner space separated by a partition wall into at least first and second space parts, the first space part being a second fluid inlet space and the second space part being a second fluid outlet space,
• said hollow housing comprises inlet and outlet openings communicating respectively with said second fluid inlet space and said second fluid outlet space and situated adjacent said inlet/outlet header and said fluid return header, respectively, and
• said second flow channels comprise channels extending in said second fluid inlet space, transverse to an axis of said hollow housing, in one direction, and channels extending in said hollow housing, transverse to the axis of said hollow housing, in a direction opposite to said channels extending in said second fluid inlet space, transverse to the axis of said hollow housing, and said first and second space parts communicate with one another through an opening in said partition wall.