On the way in to work, I pass through "Hospital Alley". I saw a collection of Praxair tanks with radiating fins that were covered in ice. If you put fins on something that's cold, it will warm up faster. I was trying to figure out why they would have a system that was designed to warm up the gases. You wouldn't want to do that with N or CO2 since their raison d'etre is as a freezing agent. Radiating fins would defeat the very thing they are trying to do. The only one I can think of is Oxygen. That's a gas that you'd store as a liquid but use as a room temp gas. Any others that a hospital might use? I looked up Praxair, they are suppliers of oxygen, nitrogen, argon, carbon dioxide, helium and hydrogen.