Finless heat exchanger, outdoor unit of an air-conditioning apparatus including the finless heat exchanger, and indoor unit of an air-conditioning apparatus including the finless heat exchanger

A finless heat exchanger, comprising:

• a pair of headers each including
• a pipe-shaped portion extending in a first direction, and
• a plurality of branching portions formed on the pipe-shaped portion at a predetermined interval in the first direction;
• and
• a pipe group including a plurality of flat pipes each having a flat sectional shape elongated in one direction, the plurality of flat pipes being arrayed in the first direction and connecting between the plurality of branching portions of one of the pair of headers and the plurality of branching portions of an other of the pair of headers,
• the finless heat exchanger having at least one passage structure in which a flat surface of one of adjacent two flat pipes and a flat surface of an other of the adjacent two flat pipes of the plurality of flat pipes of the pipe group face each other and in which the adjacent two flat pipes of the plurality of flat pipes of the pipe group each have a side surface facing a second direction orthogonal to the first direction,
• the finless heat exchanger being configured to exchange heat between air flowing through spaces defined by the plurality of flat pipes and refrigerant while the refrigerant is supplied from one of the pair of headers to the plurality of flat pipes to flow to an other of the pair of headers,
• the plurality of flat pipes being each bent in a wave shape and connect between the plurality of branching portions of the one and the other of the pair of headers, and the side surface of each of the plurality of flat pipes having a wave shape as viewed in the second direction,
• each of the flat surfaces of the plurality of flat pipes having corrugations in a wave shape with mountain fold lines and valley fold lines of the wave shape that continues from a side corresponding to one side surface to a side corresponding to an other side surface in a width direction,
• the mountain fold lines and the valley fold lines of the wave shape of each of the plurality of flat pipes being inclined in an oblique direction to a horizontal direction,
• the mountain fold lines and the valley fold lines of the wave shape of each of the plurality of flat pipes being aligned in height with the mountain fold lines and the valley fold lines of a flat pipe of the plurality of flat pipes that is adjacent,
• the plurality of flat pipes of the pipe group that are adjacent to each other being prevented from being held in contact with each other,
• both the side surfaces being opened so that the air flows in from the side corresponding to the one side surface in the second direction and flows out from the side corresponding to the other side surface in the second direction.