Hi,
An important parameter you must check about your Peltier device is the Max surface temperature - differential you are allowed.
Exceeding this will cause the element to fail.
So if you are cooling you need to also monitor the HOT side of the Peltier element and shut down if that figure is approached.
If you find it is reached in normal opertation, you will need a bigger heatsink, and/or ventilation fan.
Can you post a link to the data/specs of your Peltier Device please.
Have you worked out how much heat energy you will have to dissipate?
Thanks.. Tom.. 