I played around with a couple Peltier junctions a while back. Originally thought to use one for a new form of cooling for my overdriven CPU on my computer.
That experiment ended up costing me $100 for a new CPU. That was back when I had more money than common sense.
Next I tried using two of them to help chill the water for a closed circuit cooling system on the CPU. The two of them lowered the cooling water a whopping 2 degrees F. Then the water block on the CPU sprung a leak. That little experiment cost me another $100 for another CPU, $75 for a replacement sound card, and $40 for a relacement power supply.
It was at that point that I gave up on alternative cooling systems for my computer and went back to the trusty heat sink and a massive fan.
My prognosis as to Peltier junctions?
They work pretty good for small scale cooling of Coleman ice boxes. That's about it.