exiting from the column 22 may pass via line 25 through the heat exchanger 28 or in an alternative embodiment may pass via line 33 to the moisture stripper column 32 a portion of dry compressed gas may be taken from the discharge line 27 and delivered via line 34 to the stripper column 32 such that it may pass in contact with the fluid in the circuit 6 after it has left the absorber column 22 where it has picked up moisture the dry air or gas delivered to the stripper column 32 effectively dries the fluid passing through the stripper column 32 before it enters the absorber column 22 moisture picked up by the gas air passing through the stripper column is discharged via line 35 as vapour diverting dry compressed gas from the discharge line 27 in this way provides an inefficiency in the system and therefore it is desirable to minimize the amount of dry gas diverted from the line 27 liquid moisture absorber medium entering the absorber 22 should be cool for proper operation and accordingly a cooler 70 may be provided in the line 23 following the pump 30 leading to the absorber 22 the pump 30 may be any known type including electrically driven or air driven pumps utilizing compressed air from the discharge 27 as a possible alternative to the cooler 70 a heat exchanger 71 may be provided between the line 23 and the line 29 with arrangements as illustrated in fig2 and 3 the liquid within the substantially closed circuit 6 need not be particularly hygroscopic in nature but improved performance may be achieved if it was hygroscopic in nature glycol based fluids may be suitable for this application including glycol based lubricants such as ingersoll.