If your instruments/clocks were insensitive to variations in line voltage you could vary your rooms line voltage with a variable auto transformer (end up being a heater with tons of surface area). Or pack enough OCXOs in there so they end up thermally servoing the room.
On Wednesday, 26 October 2016, jimlux <[email protected]> wrote: > On 10/26/16 10:58 AM, John Ackermann N8UR wrote: > >> On 10/26/2016 1:00 PM, Richard (Rick) Karlquist wrote: >> >>> On 10/26/2016 8:59 AM, John Ackermann N8UR wrote: >>> >>>> I may have the opportunity to build a small "clock room" and am >>>> considering whether I could make it an environmentally controlled space. >>>> I'd like to learn about the options for doing this. >>>> >>>> The space would probably be 6x8 feet or so, in a basement with one >>>> outside wall. >>>> >>> >>> I'm lost with the basic concept here. Help me understand this. >>> >> >> This room would be a large closet in my basement where two racks of >> various OCXO, Rb, Cs live. There wouldn't be a lot of in-and-out >> traffic. I'm not looking for 0.01 degree regulation -- <1 degree C and a >> few percent humidity throughout the year seems a reasonable goal. >> >> > Heating is easy (proportional control of a resistive heater) > > 1C is going to be very tough unless you have some way to variably mix cold > dry air from your cooler with room air. Air conditioners don't like being > short cycled. > The challenge is that "cold" is usually available in a bang/bang way, so > you need something to low pass filter it. > > If you had a large source of cold water, you could use a proportional > control valve and some sort of radiator with a fan. > > Or, have a massive thermal sink between your "controlled space" and "where > the ac unit is".. If you imagine a meter thick slab of, say, Gold (good > conductivity, very high density), it would act as a very effective low pass > filter between the cycling of your AC unit and your controlled space. > > I started my control system by putting a 5 gallon bucket of water in a > refrigerator, and then using a variable speed pump into a radiator in the > chamber. This worked quite well, but you run into all the problems with a > liquid loop system: stuff grows in the water, water corrodes stuff, it > leaks, etc. > > > > > > > > What I envisioned was a very small heat pump or other heating/air-con >> unit coupled with some sort of proportional control. I just don't know >> where to start looking for that, or what other issues to be thinking >> about. >> >> (I know the way time-nuts think, and I recall the great ideas posted >> here in the past about using an old refrigerator, or burying standards >> in a deep hole -- but this would be wrapped into a bigger construction >> project that I'm going to be managing from a distance, so I need to keep >> it fairly straight-forward.) >> >> Thanks, all! >> >> John >> ---- >> _______________________________________________ >> 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/m > ailman/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.
