UltraTech LEEC species

[xilman]

Any black hole larger than 0.0075 x Earth's mass will be colder than the CMBR, so could be used as a heat dump even without a suprashell.
http://xaonon.dyndns.org/hawking/

There are two problems I see with this proposal. First, the region near the event horizon has to be kept very clean or turbulence in the in-falling matter will raise it to very high temperatures.

Much more important is that the surface area of a modest sized black hole is very small, being only a few square kilometres for one of solar mass. Going to be difficult to get significant amounts of heat down there without converting it to a more condensed form first --- which runs up against sundry thermodynamical problems.