HEAT EXCHANGER AND DEHUMIDIFIER

To provide a heat exchanger capable of easily increasing a surface area in which a gas directly contacts with an outer surface of a heat transfer pipe.SOLUTION: A heat exchanger has multiple heat transfer pipes 21. In the heat exchanger, a gas 23 flows from the upstream to the downstream at the outer side of the heat transfer pipes 21. The heat transfer pipe 21 includes a first outer surface 36, a second outer surface 38, and a third outer surface 39. The first outer surface 36 spreads along a second direction intersecting with a first direction 34 from the upstream to the downstream. The second outer surface 38 spreads from one end of the first outer surface 36 along a third direction 37 opposite to the first direction 34. The third outer surface 39 spreads from the other end of the first outer surface 36 along the third direction 37. An end as seen in the third direction 37 of the second outer surface 38 and an end as seen in the third direction 34 of the third outer surface 39 are located close to each other.SELECTED DRAWING: Figure 3 【課題】気体が伝熱管の外面に直接当たる表面積を容易に増やすことが可能な熱交換器を提供する。【解決手段】熱交換器は、複数の伝熱管２１を有する。熱交換器は、気体２３が伝熱管２１の外側を上流から下流へ流れる。伝熱管２１は、第１外面３６と、第２外面３８と、第３外面３９とを備える。第１外面３６は、上流から下流へ向かう第１方向３４に交差する第２方向に沿って広がる。第２外面３８は、第１外面３６の一端部から第１方向３４とは逆向きの第３方向３７に沿って広がる。第３外面３９は、第１外面３６の他端部から第３方向３７に沿って広がる。第２外面３８の第３方向３７における端部と第３外面３９の第３方向３４における端部とが互いに接近している。【選択図】図３