Patent ID: 7337832

Claim:
A heat exchanger comprising: a first end tank; a second end tank opposite the first end tank; a first tube in fluid communication with the first and second end tanks, the first tube adapted to have a first fluid flow therethrough, the first tube having a hydraulic diameter less than 1.00 mm, the first tube defining a plurality of sub-passageways extending along a length of the first tube wherein each of the sub-passageways of the first tube has a cross-sectional area perpendicular to the length of the first tube that is between about 0.02 mm 2 and about 1.00 mm 2 ; a second tube in fluid communication with the first and second end tanks, the second tube also being in fluid communication with the first tube such that the first fluid, during operation of the heat exchanger, flows through the second tube after the first fluid flows through the first tube, the second tube having a hydraulic diameter greater than 1.00 mm; and at least one fin contacting the first tube and the second tube, with the first tube and second tube and the at least one fin being generally co-planar relative to each other.