[time-nuts] TECs in cooling below ambient

[ed breya]

This recent TEC talk reminded of some of my long term planned projects, 
and related issues. I have at least four "someday" projects involving 
TECs, to regulate device temperatures near or below "normal" room 
temperature, including a high precision DC voltage standard, a sub-fA 
electrometer circuit, a constant temperature block for nonlinear analog 
computing elements, and a small general purpose heat/cool box for device 
and circuit testing. Each has its own particular system, application, 
and environment issues, but common to all is the lower limit of running 
temperature, based on the local climate conditions and dew point. I plan 
to estimate the lowest possible operating temperatures for expected 
conditions, that avoids condensation, and not having to resort to 
special packaging.

An essential thing for this is a dew point calculator. I found lots 
online, but this is my favorite so far. It's slider-based, so you don't 
even have to enter numbers.

http://www.dpcalc.org/

The harder part is finding the normal range of local climate conditions.

Ed