Where will you be getting all that mass from, though? > We super-heat some dense materials This won't work as you would need to put in additional work (leadin

Where will you be getting all that mass from, though? > We super-heat some dense materials This won't work as you would need to put in additional work (leading to additional waste heat) in order for this process to lower ambient temperature. The only thing you could do is shoot stuff out that's precisely at ambient temperature, compare https://news.ycombinator.com/item?id=28471620 https://news.ycombinator.com/item?id=28471620 .