Heat exchanger and manufacturing method thereof

A heat exchanger comprising:

• a partition wall that separates two fluids of different temperature;
• and
• multiple plate-shaped fins formed on at least one surface of the partition wall and each having a pair of heat transfer surfaces,
• wherein the partition wall and the multiple fins are made of a same metal material to constitute an integrally molded product,
• the multiple fins each have a curved part and are arranged to be spaced from one another in a direction intersecting with the pair of heat transfer surfaces, and
• each heat transfer surface of the pair of heat transfer surfaces is formed with multiple grooves having a depth of 100 μm to 400 μm in a thickness direction of each fin,
• wherein the heat exchanger further comprises plate-shaped members each being made of another metal material having a higher emissivity than the metal material of the partition wall and the multiple fins, and attached to the partition wall between adjacent ones of the multiple fins,
• wherein the partition wall constitutes a bottomed tubular body, and
• the plate-shaped members are fitted into multiple mounting grooves formed on an outer surface in a bottom portion of the partition wall,
• wherein the multiple fins are each connected to a bottom surface and a side circumferential surface of the bottomed tubular body that form an outer surface of the bottomed tubular body,
• in a first portion of each fin connected to the bottom surface of the bottomed tubular body, the multiple grooves each extend toward the bottom surface, and
• in a second portion of each fin connected to the side circumferential surface of the bottomed tubular body, the multiple grooves each extend substantially vertically.