HEAT EXCHANGER FOR PROVIDING SUPERCRITICAL COOLING OF A WORKING FLUID IN A TRANSCRITICAL COOLING CYCLE

摘要

A heat exchanger (10) preferably provides supercritical cooling to the refrigerant of a transcritical cooling system (12). The heat exchanger (10) includes a pair of elongated headers (20, 22) having longitudinal axes (24, 26) disposed substantially parallel to each other, a plurality of elongated tubes (28) spaced in side-by-side relation along the longitudinal axes (24, 26) of the headers (20, 22), and serpentine fins (30) extending between adjacent pairs of the tubes. Each of the tubes (28) has a first end (31) connected to the header (20) and a second end (32) connected to the other header (22) to the headers (20, 22). Each of the tubes (28) is folded upon itself to define at least two parallel legs (36) of the tubes (28) so that the refrigerant flows serially through at least two parallel fluid passes (38) from the header (20) to the header (22) Each of the tubes (28) has a flattened cross-section, and the parallel legs (36) of each of the tubes (28) are preferably spaced from each other, with the major dimension D of each of the parallel legs lying in a common plane. Preferably, each of the serpentine fins (30) has a transverse width W extending across the parallel legs (36) of the adjacent tubes (28). Each of the fins (30) includes a plurality of alternating tabs (40) and elongated separations (42) extending parallel to the parallel legs (36) and located between the parallel legs (36) of the adjacent tubes (28) to divide the width W of each fin (30) into two or more discrete fin elements (44) that are connected to each other by the tabs (40). Each of the fin elements (44) corresponds to and extends along one of the parallel legs (36) of each of the adjacent tubes (28).