On Wed, Sep 26, 2012 at 11:05 PM, Hal Murray <hmur...@megapathdsl.net> wrote: > >> As you go deeper you get a delayed history of the surface temperature. > > Right. Skin depth. > > >> A good oven runs rings around deep earth stability. > > But a hole in the ground doesn't take any power. >
That was my point. At some depth you get less then a degree of day/night and summer/winter variation. That is very good for zero power input. Yes a precision controller could do better. I onced used a Peltier device with water heat sink all running in a vacuum insulated jar. It kept the temperature pretty much dead-on but at high cost in bulk (55 gal.drum of coolant) and plumbing and in power. But you get 0.3C error for free and it runs for years on "nothing" It's a trade off. Chris Albertson Redondo Beach, California _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
