Tube structure of micro-multi channel heat exchanger

A heat exchanger comprising:

• a first elongate header for receiving refrigerant;
• an second elongate header facing said first header;
• a plurality of tubes spaced at intervals from each other along a length direction of said first and second headers, each of said plurality of tubes having a flattened profile and a cross sectional area, taken in a direction parallel to the length direction of said first and second headers, which reduces in width from an air inlet side of said heat exchanger to an air outlet side of said heat exchanger, each of said plurality of tubes having a first end fixed to said first header and a second end fixed to said second header, each of said plurality of tubes including a plurality of channels communicating between said first header and said second header, each of said plurality of channels having a cross sectional area taken in a direction parallel to the length direction of said first and second headers, wherein the cross sectional areas of individual channels reduce from said air inlet side of said heat exchanger to said air outlet side of said heat exchanger;
• and
• a plurality of fins between said plurality of tubes for heat exchange with air, wherein the cross sectional areas of individual channels are substantially trapezoidal, having one side facing said air inlet side of said heat exchanger longer than another side facing said air outlet side of said heat exchanger.