[time-nuts] Hobbyist grade or homebrew temperature testing chamber?

Adrian Godwin artgodwin at gmail.com
Tue Sep 6 04:19:21 EDT 2016


On Tue, Sep 6, 2016 at 4:24 AM, Bob Darlington <rdarlington at gmail.com>
wrote:

> Rick,
>
> I'm going from memory here.  My former business partner (now deceased) had
> a "beer fridge" setup as an environmental chamber for our instruments.  The
> trick for stability was to run the AC compressor all the time, and push
> against it with heat lamps.



I had a commercial environmental chamber  : it did exactly this.  The
fridge unit could be controlled from an auxiliary output of the PID
controller but the basic principle was to heat from ambient, or heat
against the fridge for lower temperatures. Maybe Peltier systems can have a
cleaner rollover for cooling, but gas-based coolers have far too much
settling time / transients / hysteresis to be actively in the control loop.



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