Putting anything warm or that generates heat inside a fridge will cause condensation on that object. running cold water pipes from the dispenser will cause condensation, and may even sneak under any insulation. I've seen this type of mod attempted before several times.
on another note:
The water in the plastic tank is not cooled btw, it's room temp. The water goes to a small 4 liter cooling reservoir where it sits for a while until you dispense it. The unit will not be able to cool water fast enough, in about 2 minutes of use (assuming its a 150GPH typical DangerDen pump)
it will drain the entire 5 Gal tank, and you will be running room temp water straight from the res. If you push it, the small compressor in this unit will burn out from constantly running, trying to reach the preset cooling temps. Once the compressor gets too hot, the sensors will turn it off to prevent siezure, or even fire.
assuming that in some strange bizzaro alternate universe the unit
can keep up with providing cold water to cool the PC, in a matter of minutes you will be introducing very cold water into the plastic reservoir. This will cause mucho condensation that will gather around the tank and well...being water it just loves gravity and will soon collect on the bottom of the unit, and your floor.
You would have decent CPU temps for about 60 seconds, but Your electric bill would be astronomical
