A Dewar system is configured to liquefy a flow of fluid, and to store the liquefied fluid. The Dewar system is disposed within a single, portable housing. Disposing the components of the Dewar system within the single housing enables liquefied fluid to be transferred between a heat exchange assembly configured to liquefy fluid and a storage assembly configured to store liquefied fluid in an enhanced manner. In one embodiment, the flow of fluid liquefied and stored by the Dewar system is oxygen (e.g., purified oxygen), nitrogen, and/or some other fluid.