| abstract |
A method of transferring gas, such as hydrogen gas for vehicles, comprises expanding a process gas having a first temperature to produce a first volume of the process gas that has a higher temperature, and a second volume of the process gas a lower temperature. The method further comprises displacing at least some of the second, cooler, volume of the process gas into the receiving vessel 13 using a piston gas, wherein the piston gas is of the same type as the process gas. Also disclosed is an apparatus, comprising an auxiliary vessel (111, figure 4) a first vessel (121, figure 4) and a second vessel (122, figure 4) and a receiving vessel (113, figure 4), where the first and second vessels are connectable, the first vessel can connect to the receiving vessel, and where gas can flow from the auxiliary vessel to the first vessel without passing through the second vessel. |