Brad sums it up quite right.
A Pelt simply transfer heat from one side to the other: it still needs to be cooled. The advantage is that they can lower a temperature below ambiant.
That being said, Pelts can be air-cooled, if they're low-power, but otherwise will require a water cooling solution. See Brad's recommendations for HS and fan.
This link might help:
http://www.dansdata.com/coolercomp.htm