A search for "superconductor heat pipe" says Niven is right and superconductors can be used for super-fast cooling.
A superconducting wine glass that fits onto a superconducting cold spot on the table. Or a superconducting sleeping bag for those hot mosquito nights. (The sleeping bag also levitates on magnetic lines so you can sleep on air.)
Unfortunately, electrical superconductors are terrible conductors of heat. Metals conduct heat well because the conduction electrons occassionally scatter off of a thermal vibration, are accelerated, and the travel a good long distance before scattering again.
But in a superconductor, the conduction electrons are bonded to each other by quantum mechanics magic. It takes a lot of energy to break one loose, more than you can get from heat. In fact, if the material was hot enough to scatter many of the electrons (the critical temperature), it would stop superconducting. Basically, superconding electrons are a perfect mirror for heat.
I have some hope for composite materials made with superconductors. Long nanowhiskers might be able to serve as antennas that carry infrared signals from point A to point B.
If they are there would be a lot of applications on that front as well.