Flat pipe

A heat exchanger,

• wherein the heat exchanger comprises a plurality of flat tubes, wherein the each of the flat tubes of the plurality of flat tubes is a flat tube having
• (i) two opposing, substantially flat first walls arranged parallel to one another, two curved second walls connecting the two flat first walls, and
• (ii) an interior space bounded by the substantially flat first walls and the curved second walls through which a medium can flow, a first plurality of projections arranged on the substantially flat first walls protruding into the interior space, a second plurality of projections arranged on the curved walls protruding into the interior space, and a third plurality of projections arranged on the substantially flat first walls protruding outwardly and away from the interior space;
• wherein the projections from the first plurality of projections are elongated having a greater length than width and are each arranged in a repeating pattern alternating between an x-shape and an o-shape such that each projection of the first plurality of projections forms part of an x-shape or part of an o-shape, wherein the x-shape and the o-shape each consist of four distinct projections, wherein each x-shape in the repeating pattern is adjacent to an o-shape and each o-shape in the repeating pattern is adjacent to an x-shape.

A flat tube having

• two opposing, substantially flat first walls arranged parallel to one another, two curved second walls connecting the two flat first walls,
• an interior space bounded by the substantially flat first walls and the curved second walls through which a medium can flow, a first plurality of projections arranged on the substantially flat first walls projecting into the interior space, a second plurality of projections arranged on the curved walls protruding into the interior space, and a third plurality of projections arranged on the substantially flat first walls protruding outwardly and away from the interior space,
• wherein both of the opposing, flat first walls each have projections from the first plurality of projections protruding into the interior space, wherein both of the opposing, curved second walls have projections from the second plurality of projections protruding into the interior space, wherein both of the two opposing, substantially flat first walls have outward-facing projections from the third plurality of projections,
• wherein the projections from the first plurality of projections are elongated having a greater length than width and are each arranged in a repeating pattern alternating between an x-shape and an o-shape such that each projection of the first plurality of projections forms part of an x-shape or part of an o-shape, wherein each x-shape in the repeating pattern is adjacent to an o-shape and each o-shape in the repeating pattern is adjacent to an x-shape, wherein there are no projections arranged between the x-shape and the o-shape in the repeating pattern,
• wherein the x-shape and o-shape each consist of four distinct projections,
• wherein the outwardly protruding projections from the third plurality of projections are arranged inside the o-shape in every instance,
• wherein the projections from the first plurality of projections are arranged so as to complement one another, so that an x-shaped arrangement in a first wall of the substantially flat first walls is situated opposite an o-shaped arrangement of an opposing second first wall of the substantially flat first walls,
• wherein the projections from the second plurality of projections have an oval cross section with respect to a surface of the curved second walls,
• wherein a center of a projection from the second plurality of projections is substantially aligned with a center of a projection from the first plurality of projections,
• wherein the flat tube does not have any projections other than the first plurality of projections, the second plurality of projections, and the third plurality of projections.