> Having recently installed an "Earth Tube" I have investigated this issue a
> bit.
> The Earth Tube I have installed is to provide cooling to only a fresh
> produce
> storage cupboard so is quite different to what you want to do. Mine is a
> minimalist (not much to lose) project whereas yours will require a very
> significant capital outlay if it is to be successful. Design cost may
> outweigh
> implementation cost.
>
> The following link provides balanced (but very basic) information I think.
>
>http://www.eere.energy.gov/consumer/your_home/space_heating_cooling/index.cfm/
> mytopic=12460
>
> The approach has been used successfully & repeatedly in cooling piggeries so
> suggest your research include this angle.
>
> In my view there has not been enough successful projects of this type to
> date
> to enable development of rules of thumb which one can use with any
> confidence.
> .
>
> So its probably back to first principles which will require design, design &
> more design preferably by an engineer experienced/practising in this area of
> thermodynamics.
>
> You will need to know basic stuff like knowing the temperature profile of
> your
> ground at specific depth over the year.
>
> I have seen quite detailed engineering design guides/information for these
> devices so keep googleing.
>
> Laurence Gaffney
> Australia
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