Heat exchanger and air conditioner employing the same

An air conditioner comprising:

• an outdoor heat exchanger;
• and
• an indoor heat exchanger,
• wherein at least one of the outdoor heat exchanger or the indoor heat exchanger includes:
• a first header into which a refrigerant for performing heat exchange with a fluid is introducible,
• a second header from which the refrigerant is discharged,
• a tube, having a flat tube form, into which the refrigerant in the first header is introduced such that the refrigerant flows through the tube to be discharged to the second header, wherein the tube has an upper surface which is parallel to a flow direction of the fluid and a lower surface opposite to the upper surface,
• a first fin on the upper surface of the tube and including:
• a plurality of ridges and a plurality of valleys alternately arranged along a longitudinal direction of the tube, and
• downwardly protruding portions that protrude from respectively corresponding valleys of the first fin toward the lower surface of the tube and that contact one end of the tube, and
• a second fin on the lower surface of the tube and including:
• a plurality of ridges and a plurality of valleys alternately arranged along the longitudinal direction of the tube, and
• upwardly protruding portions that protrude from respectively corresponding ridges of the second fin toward the upper surface of the tube and that contact the one end of the tube.