Hello Svenry, I would be glad to inform you that you should be able to use an USB 3.0 hub using the USB ports from the DN2820FYK NUC.
USB voltage is standard; therefore the USB ports from the DN2820FYK will provide a 5 volt DC.
Please check the following link for additional information on USB http://en.wikipedia.org/wiki/USB
What's the current output supported by the USB 3.0 ports in the current gen NUCs?
I've seen pics of the newer ones, which have a yellow port. That often indicates that it's a "charging" port, and will provide more juice for your power hungry devices (and will also do it when the PC is off/suspended). So I'd suspect those will provide more current.