[time-nuts] Fwd: Re: in-ground clock room

[ed breya]

Hi all, I've been trying to figure out the right email address for 
replies to the group. When I tried to send this message the other day, 
to the automatic address in the archive listing, it was rejected. I was 
just looking again today, and I see the discrepancy, I think. I'm now 
sending to the address that shows in the email digests, not the one at 
the archive site, so this is kind of an experiment. Hope it works.  Ed


-------- Forwarded Message --------
Subject: 	Re: [time-nuts] in-ground clock room
Date: 	Fri, 10 Sep 2021 12:48:41 -0700
From: 	ed breya <eb at telight.com>
To: 	time-nuts_lists.febo.com at febo.com


As you can see from the discussion, there are all sorts of complications
and issues with making and using an underground equipment pit. To get
decent thermal stability, you have to go pretty deep, and there will be
never-ending problems with ground water, rain water, and humidity. And
of course, earthquake isolation, and cost of construction and so on.

I'd recommend instead, making it all on- and above-ground. You could
say, pour a large, thick one-piece concrete slab for the foundation.
With enough base rock underneath, plenty of rebar, and maybe 8-12 inch
thickness, I think you can easily span up to 10-12 feet square without
relief joints. This would provide a single massive base, and can be set
nice and flat and level instead of sloped for drainage, so making a good
reference plane for everything else. For smaller size, it's much easier,
of course.

Then you can build or park whatever massive structure you want on it,
and even get fancy with earthquake isolation and such. Then, if you've
planned ahead and put foundation bolts in the concrete around the
perimeter, you can build a nice sturdy shed around it, to contain and
protect the support equipment like power system, heat pump, humidity
control, backup battery bank, instrumentation, etc. You can even top it
off with a solar PV array on the roof, to help with the power demand.
The shed can be insulated as much as you want, to help even things out.

For thermal control, a bidirectional heat pump can serve all seasons,
and you could even go with a small geothermal setup. It's a lot easier
to drill some holes as deep as practical, than dig a large pit. Then,
instead of putting the vault deep down for stability, you can bring some
of the ground and water table stability to the vault, by circulating
water through buried heat exchangers. The right setup may provide enough
BTU/hr to control the temperature reasonably well alone, or at least
greatly improve the heat pump efficiency.

There are all sorts of options that may come to mind once the concept is
set up. It's kind of like designing and building a piece of equipment -
start with an adequate chassis, then add on from there, until there's no
more room left inside.

Ed