Heat exchanger and absorption refrigerator

A heat exchanger configured to transfer heat between a first fluid on a periphery of a heat transfer tube and a second fluid in an interior of the heat transfer tube, the heat exchanger comprising:

• a first heat transfer tube unit comprising a plurality of first heat transfer tubes arranged in parallel with one another along a first direction within a horizontal plane;
• and
• a second heat transfer tube unit comprising a plurality of second heat transfer tubes arranged in parallel with one another along a second direction that intersects the first direction within the horizontal plane,
• wherein each of the plurality of first heat transfer tubes comprises:
• a plurality of first straight portions arranged in parallel with and spaced from one another in a vertical direction;
• and
• one or more curved portions that make end portions of the first straight portions communicate with each other, and
• the plurality of first heat transfer tubes form one flow path from an inlet header to an outlet header,
• wherein each of the plurality of second heat transfer tubes comprises:
• a plurality of second straight portions arranged in parallel with and spaced from one another in the vertical direction;
• and
• one or more curved portions that make end portions of the second straight portions communicate with each other, and
• the plurality of second heat transfer tubes form one flow path from the inlet header to the outlet header, and
• wherein the first straight portions and the second straight portions are stacked on each other alternately.