The invention relates to a heat exchanger (1) for indirect heat exchange comprising a tube bundle (10), formed from a plurality of tubes helically coiled around a core tube (100), for receiving a first medium, a shell (20). which encloses the tube bundle (10) and defines a shell space (200) surrounding the tube bundle (10), for receiving a second medium, and a liquid distributor (40) for distributing in the shell space (200) a stream (S), conveyed in the shell space (200), of the second medium in the form of a liquid (F). According to the invention a control device (33) for controlling distribution in the shell space (200) of an additional, further stream (S′) of liquid (F), and/or for controlling distribution of stream (S) of liquid (F) in the shell space (200).