[time-nuts] SMPS or conventional?

[ed breya]

Regarding TEC life, in my experience, what wrecks them the most is 
cooling applications where the cold side is below the dew point, and 
water condenses out onto and into the TEC Peltier array. This eventually 
rots the elements from corrosion and electrolysis, until something craps 
out. If the TEC will be exposed to ambient air, and run below or even 
near the expected dew point, the sides should be sealed up with silicone 
goop for longer life. Even then, it's not foolproof, since it will never 
be a perfect seal.

If the TEC is in a closed, benign environment or vacuum, then it should 
last indefinitely, unless abused power-dissipation-wise, or mechanically 
by thermal stress. When the temperature cycles, the whole part must be 
allowed to change dimensions slightly, so the mounting needs to have 
some compliance.

Ed