Heat exchanger

A heat exchanger comprising:

• a plurality of flat heat transfer tubes in each of which a plurality of first flow channels and a plurality of second flow channels are formed in an interior portion of each of the plurality of flat heat transfer tubes;
• and
• a header in which an insertion space is formed, wherein
• the header includes
• a pipe penetration wall portion through which the plurality of flat heat transfer tubes pass such that the plurality of first flow channels are connected to a first space included in the insertion space and the plurality of second flow channels are connected to a second space included in the insertion space, the pipe penetration wall portion being provided with a first inner wall surface that is in contact with the first space and a second inner wall surface that is in contact with the second space,
• an inlet portion that supplies a refrigerant to the first space such that:
• the refrigerant supplied to the first space contains a first refrigerant flowing toward the first inner wall surface and a second refrigerant flowing toward the second inner wall surface;
• an amount of the first refrigerant is greater than an amount of the second refrigerant;
• and
• the first refrigerant comes into collision with the first inner wall surface and is separated into a gas refrigerant and a liquid refrigerant, and
• a wall that divides the insertion space into the first space and the second space to block flow of the gas refrigerant from the first space to the second space, and
• the wall is away from the pipe penetration wall portion such that a communication path through which the liquid refrigerant flows from the first space to the second space is formed between the wall and the pipe penetration wall portion.