A liquid cryogen stored in a liquid cryogen space of a closed insulated cryogenic storage vessel is subcooled by allowing it to enter into a conduit disposed in the liquid cryogen space where it is expanded by a pressure reducer in the conduit, thereby producing a cooled biphasic mixture of the cryogen in liquid and vaporized forms. The cooled biphasic mixture has a temperature lower than that of the liquid cryogen in the liquid cryogen space. Heat is transferred across the conduit from the liquid cryogen in the liquid cryogen space to the cooled biphasic mixture.

A liquid cryogen stored in a liquid cryogen space of a closed insulated cryogenic storage vessel is subcooled by allowing it to enter into a conduit disposed in the liquid cryogen space where it is expanded by a pressure reducer in the conduit, thereby producing a cooled biphasic mixture of the cryogen in liquid and vaporized forms. The cooled biphasic mixture has a temperature lower than that of the liquid cryogen in the liquid cryogen space. Heat is transferred across the conduit from the liquid cryogen in the liquid cryogen space to the cooled biphasic mixture.