Can you just close the system and let the item self heat. Then you only ever have a cooling problem. Seems I am familiar with a very large computer manufacture who does it that way.
On Thu, Sep 9, 2010 at 5:14 PM, J. Forster <[email protected]> wrote: > Peltier devices have been used as temperature control elements for > decades. I've never heard of fatigue failures, but, if I were designing a > chamber as you suggest, I'd try to keep the temperature differential > across the TE element under maybe 15 to 20F. The harder you push it, the > greater the stress. > > Also, the heat pumping power falls dramatically as the delta-T increases > and it's a situation of rapidly deminishing returns. > > I'd not worry much about ramping the drive. > > FWIW, > > -John > > =============== > > > > > Does anybody know about using the same Peltier junction for both heating > > and cooling? > > I'm concerned about thermal/mechanical shock when changing the polarity > > back-n-forth between hot and cold. Maybe there needs to be a controlled > > ramp, if so then how do I figure out the rate? > > > > Why: > > I'm in the process of building a small environmental chamber for my home > > lab. The volume is ~30 liter, target temp range of 0C to 60C. For the > > cooling side I am using water circulation (radiator, pump, reservoir & > > water block) and Peltier junctions. At first I was planning to have two > > separate systems, one for heating and one for cooling, but then I got to > > thinking that using just the water and Peltier could be used for both. I > > will be using a PID for temp control, and two TEC1-12726 Peltier > Qcmax(w)= > > ~240 △T =0j > > > > > > Regards, > > Jerome > > > ----------------------------------------------------------------------------------- > > This email message is for the sole use of the intended recipient(s) and > > may contain > > confidential information. Any unauthorized review, use, disclosure or > > distribution > > is prohibited. If you are not the intended recipient, please contact the > > sender by > > reply email and destroy all copies of the original message. > > > ----------------------------------------------------------------------------------- > > > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
