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<div class="moz-cite-prefix">G'day Kyle,<br>
<br>
Yes, we had birds and mice pull out rockwool insulation and when
we tried styrene balls they leaked out any holes. If you are
underground you need to keep water away, so closed cell foam would
be good (but possibly expensive) - as others have said you have to
look at what is available locally (and relative costs may change
considerably, so what is cheap here may be very expensive where
you are).<br>
<br>
Happy dgesting,<br>
HOOROO<br>
<pre class="moz-signature" cols="72">Mr Paul Harris BEng (Ag) (Melbourne)
Visitor at The University of Adelaide</pre>
On 4/10/2012 11:55 PM, Takamoto wrote:<br>
</div>
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cite="mid:11BEC451-AEB6-40AA-B94C-F9C1F79FA7AF@takamotobiogas.com"
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Dear Biogas List,
<div><br>
</div>
<div>Thank you all for the advice and encouragement. It can be
done which is good news. </div>
<div><br>
</div>
<div>Mr. Karve, could you explain your concept a little bit more?
Is it passive or active (requires a pump)? and what is the name
of the sponge rubber insulation material?</div>
<div><br>
</div>
<div>Manuel, you mention that electricity is required for control.
It seems that a battery could be used for control and last for
several years. Is this true? At most you could use a tiny solar
panel to charge a battery for all of the control power you need.
How much stirring is actually required? If you are heating the
bottom of the digester then there should be some convection in
the tank just from thermal differences. Even so, I think I have
seen that stirring only increases gas production by around 20%.</div>
<div><br>
</div>
<div>Peter, how much power did your system require for pumping? Is
there a way to do away with the pump? How much did a cloudy day
affect the heating system? How much power was required to run
your control system (if any)? It is good to hear that your
mesophilic digester was able to produce better fertilizer than
the ambient temperature digester. I have seen a website for a
company in Australia called biobowser. Is that the same company?
It looks like a beautiful technology all packaged into one easy
(?) to install modular unit. Is there a reason why their
smallest unit is for 100kg per day? Could their system be scaled
down?</div>
<div><br>
</div>
<div>Paul, to better understand the rough spreadsheet you made,
you found that one twelfth of the additional biogas was used for
heating so the net effect was a significant increase in biogas
to the user. Have you had bad experience with animals in your
insulation? Would you recommend avoiding some kinds of
insulation? Are there some insulations that a good for
underground installations?</div>
<div><br>
</div>
<div>One of the ideas I proposed was to bubble a small amount of
air through the digester so that there was a slight aerobic
reaction that generates heat and keeps the digester warm. Is
there any validity to this idea? Has it ever been done? Or would
the amount of oxygen required to raise the temperature of a
digester by 17C degrees kill the methanogenic bacteria?</div>
<div><br>
</div>
<div>All the best wishes,</div>
<div><br>
<div apple-content-edited="true">
<span class="Apple-style-span" style="border-collapse:
separate; color: rgb(0, 0, 0); font-family: Helvetica;
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-webkit-text-size-adjust: auto; -webkit-text-stroke-width:
0px; font-size: medium; ">Kyle</span><br>
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