Lämmönsiirrin

摘要

A heat exchanger element (1),a heat exchanger unit (10) and a heat exchanger (8). A heat exchanger element (1) is an elongated tubular element having a first end (2a) and a second end (2b) and at least one wall (3a, 3b, 3c, 3d) an inner surface of which contributes to define at least one primary flow channel (4) of the heat exchanger element (1). An outer surface of the wall (3a, 3b, 3c, 3d) of the heat exchanger element (1) comprises at least one indent (5) which opens outwards of the heat exchanger element (1) and extends in a longitudinal direction of the heat exchanger element (1), the indent (5) defining at least one secondary flow channel (6) of the heat exchanger element (1).