Patent ID: 6907922

Claim:
A heat exchanger which is used in a vapor-compression type refrigerator where a pressure of a refrigerant at a high-pressure portion reaches and exceeds a critical pressure, the heat exchanger which a low-pressure refrigerant flows through, the heat exchanger comprising: a flat tube; refrigerant channels which are included in the tube and the low-pressure refrigerant flows through; and inner pillars that are disposed between the refrigerant channels, wherein a tensile strength of material of the tube is defined as S [N/mm 2 ]; of one of the refrigerant channels, a dimension approximately parallel with a major-axis direction of the tube is defined as Wp [mm]; and, of one of the pillars, a thickness approximately parallel with the major-axis direction of the tube is defined as Ti [mm], and wherein [447×Wp/{10^(1.54×log 10 S)}−533/{10^(1.98×log 10 S)}]≦Ti≦[447×Wp/{10^(1.54×log 10 S)}−533/{10^(1.98×log 10 S)}]×2.3.