HEAT EXCHANGER

PROBLEM TO BE SOLVED: To provide a heat exchanger allowing improvement of heat radiation performance when using the heat exchanger for a gas cooler of a supercritical refrigeration cycle, and allowing miniaturization and weight saving. SOLUTION: This heat exchanger 1 has: a pair of headers 2, 3 disposed apart from each other; and a plurality of flat tubes 4 disposed at an interval in a longways direction of the headers 2, 3 between both the headers 2, 3, and each having both the end parts vonnected to both the headers 2, 3. All the flat tubes 4 have the same cross section shape. All the flat tubes 4 are divided into two paths P1, P2 comprising the plurality of flat tubes 4 vertically continuously arranged side by side. When defining a value obtained by dividing the number of the flat tubes 4 constituting each the path P1, P2 by the number of all the flat tubes 4 as 'a tube ratio', the tube ratio of each the path P1, P2 is set to be 0.45-0.55, preferably 0.48-0.52. COPYRIGHT: (C)2006,JPO&NCIPI