Well since it's on a small scale, maybe 500 million gallons of water per year might cool it off. So we are definitely in a skin melting blood boiling and non breathable hot air situation rising towards his face. -mostlu joking, I haven't done enough math to back up these claims, but it very much seems like it would be so.

You can't really dial down output from it, so I always assumed the one in his chest also has the energy to power all of the suit features.