You'll need a 400w pelt (or a combination of a few pelts) to get enough power to cool 10 degrees celcius.
Pels are not effective when it comes to cooling water. Heating water, and cooling a CPU is 200% more effective!
You'll get better results if you place a 223w pelt on your CPU.
Chillers based on pelts seem like a good idea, but they don't work that good.
The setup from Cathar is the best way to go if you want to keep it cheap. I don't want to pay your electriciy bill when you use a 400W pelt 24/7
Using a fridge will take about 180W, and will get the result you want.