Abstract: An extruded aluminum flat multi-hole tube manufactured by extrusion molding includes therein a plurality of refrigerant passages extending in a tube length direction and including an upper wall surface and a lower wall surface opposed to each other and a pair of opposed sidewall surfaces. A ridge extending in the tube length direction is formed only on the upper wall surface of the refrigerant passage. The height of the ridge is 5 to 25% of the vertical width of the refrigerant passage. The ratio of the horizontal width at ½ the height of the ridge with respect to the horizontal width of the refrigerant passage is 0.05 to 0.30. The ratio of the horizontal width per inter-ridge flat portion of the upper wall surface with respect to the horizontal width of the refrigerant passage is 0.20 or less.

Abstract: An extruded aluminum flat multi-hole tube manufactured by extrusion molding includes therein a plurality of refrigerant passages extending in a tube length direction and including an upper wall surface and a lower wall surface opposed to each other and a pair of opposed sidewall surfaces. A ridge extending in the tube length direction is formed only on the upper wall surface of the refrigerant passage. The height of the ridge is 5 to 25% of the vertical width of the refrigerant passage. The ratio of the horizontal width at ½ the height of the ridge with respect to the horizontal width of the refrigerant passage is 0.05 to 0.30. The ratio of the horizontal width per inter-ridge flat portion of the upper wall surface with respect to the horizontal width of the refrigerant passage is 0.20 or less.