Abstract: A cryogenic air separation system having a main condenser comprising a plurality of tubes having fluted external condensing surfaces upon which downflowing nitrogen vapor condenses, and having structured internal boiling surfaces upon which downflowing oxygen liquid vaporizes.

Abstract: A cryogenic air separation system wherein nitrogen vapor from a higher pressure column and oxygen liquid from a lower pressure column each pass down through a once-through main condenser in heat exchange relation and some but not all of the oxygen liquid is vaporized such that the oxygen liquid and vapor exit the condenser in a liquid to vapor mass flowrate ratio within the range of from 0.05 to 0.5 whereby the need for a recirculation pump to ensure avoidance of oxygen boiling to dryness is eliminated.

Abstract: A system for cooling a power transformer wherein cryogen in liquid or solid form is sprayed into a vaporizer or directly onto a power transformer radiator and the vaporizing and/or sublimating cryogen cools a cooling fluid within the vaporizer or cools the radiator directly to provide cooling to the power transformer.