Abstract: In an adiabatic heat exchanger, using the principle of kinetic cooling, a carrier gas is forced through a number of narrow, heat-conducting pipes wherein its velocity increases and its temperature drops. Incoming gas is forced to pass over these now cold pipes causing precipitation of a portion of the gas and an increase in temperature of the remaining portion. Such an arrangement permits for example removal of a condensible gas e.g. water vapour from a non-condensible carrier gas without the necessity of using an additional cooling medium.