Heat exchanger and air conditioner

A heat exchanger, comprising a plurality of fins and a plurality of flat pipes arranged in parallel,

• wherein each of the plurality of flat pipes comprises a first finned region, a second finned region, and a finless region, the first finned region is connected to the second finned region via the finless region,
• the plurality of fins are provided both between adjacent two first finned regions and between adjacent two second finned regions, an end of the finless region connected to the first finned region is twisted and defined as a first torsion section, the other end of the finless region connected to the second finned region is twisted and defined as a second torsion section, and a portion of the finless region between the first torsion section and the second torsion section is defined as a connecting section,
• both the first torsion section and the second torsion section are twisted at a second angle along the same direction, so that each connecting section of the plurality of flat pipes is sequentially and partially stacked on an adjacent connecting section along the same direction, and the second angle is defined as b, the second angle b satisfies a following formula:
• b
• ≤
• 90
• ⁢
• °
• -
• sin
• -
• 1
• (
• h
• h
• +
• d
• )
• ,
• wherein a thickness of each of the plurality of flat pipes is defined as h, a distance between adjacent two of the plurality of flat pipes is defined as d, and the distance d between adjacent two of the plurality of flat pipes is greater than the thickness h of each of the plurality of flat pipes.