Re: [EnergyPlus_Support] Splitting an earth tube

[John Ross <energy.wwind@xxxxxxx>]

John wrote;

NO.  Depending on how strict you are.  If you take the dirt near the 
building as being warmer than the surrounding area then you have a 
counter flow heat exchanger.... and that's not linear with flow 
direction length.

I would take two full length tubes with half the surface area per 
running foot of the big tube for the thermal calculation, but that's 
going to make the blower fan energy wrong......too high;  but the blower 
energy should be a small fraction of the total earth tube recovery so 
it's still a better result.

bye.

Danny Bishop wrote:
>
> hi All
> I have a building that has a single earth tube with two outlets 
> feeding two
> separate thermal zones. In order to implement it in E+ I need to split the
> single tube into two equivalent earth tubes - one for each zone. Now
> splitting the flows is easy - I just put the flow coming out of each 
> outlet
> to each of the two separated earth tubes.
>
> The question I have is how to adjust the dimensions (Length and 
> diameter) of
> the single tube to the two equivalent earth tubes. Is it equivalent 
> just to
> use half the length of the original tube for each of the separated tubes?
> cheers
> Danny
>
> [Non-text portions of this message have been removed]
>
>  


[Non-text portions of this message have been removed]


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