STUDY OF EXERGETIC LOSSES OCCURRING WITH LIQUID HELIUM TRANSFILL OPERATIONS

摘要

Large quantities of liquid helium are distributed in transport dewars. A considerable amount of liquid evaporates due to throttling and heat inleak when helium is filled from storage dewars into transport dewars (cans). High pressure drops in transfer lines together with storage pressures up to 1.5 bar result in high evaporation rates. In most cases the refrigeration capacity of the cold gas is not recovered. A thermodynamic analysis of the filling process which covers the liquefaction and gas recovery is presented. It is shown that low pressure in the storage tank and recovery of cold gas considerably increase the overall process efficiency.