[time-nuts] Practical considerations making a lab standard with an LTE lite

Poul-Henning Kamp phk at phk.freebsd.dk
Sun Nov 23 13:07:29 EST 2014

In message <CANX10hCaoB-5GYsbR7sdXwL7DYH7QUBMhXWmi9xDRcF3mDM7_Q at mail.gmail.com>
, "Dr. David Kirkby (Kirkby Microwave Ltd)" writes:

>> Geothermal means you drill at least 50m (Iceland) or more likely
>> half a kilometer down, in order to harvest water at near boiling
>> point from the Earths geological heat-sources (mostly uranium decay).
>Sorry.  What he installs is pipes in the ground in residential or
>industrial sites. Basically he says they work initially,  but performance
>drops dramatically over a couple of years.

That is not "geothermal" then, and yes, a LOT of those systems are
badly underdimensioned.

I've been researching this topic intensively because my new house
will be heated that way.

My conclusion, based on reading a lot of reports, is that there
is no credible way to predict the performance.  The wetter your
soil the better, but that's about it.

I'm going to overprovision by a factor two to be on the safe side,
afterall it only costs EUR7 for each extra meter of pipe.

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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