[103339] in North American Network Operators' Group
Re: rack power question
daemon@ATHENA.MIT.EDU (Dorn Hetzel)
Wed Mar 26 07:39:13 2008
Date: Wed, 26 Mar 2008 07:37:58 -0400
From: "Dorn Hetzel" <dhetzel@gmail.com>
To: "Petri Helenius" <petri@helenius.fi>
Cc: "Paul Vixie" <paul@vix.com>, "William Herrin" <herrin-nanog@dirtside.com>,
nanog@merit.edu
In-Reply-To: <47E9EBDC.4030008@helenius.fi>
Errors-To: owner-nanog@merit.edu
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I believe some of the calculations for hole/trench sizing per ton used for
geothermal exchange heating/cooling applications rely on the seasonal nature
of heating/cooling.
I have heard that if you either heat or cool on a continuous permanent
basis, year-round, then you need to allow for more hole or trench since the
cold/heat doesn't have an off-season to equalize from the surrounding earth.
I don't have hard facts on hand, but it might be a factor worth verifying.
On Wed, Mar 26, 2008 at 2:23 AM, Petri Helenius <petri@helenius.fi> wrote:
>
> Paul Vixie wrote:
> >
> > aside from the corrosive nature of the salt and other minerals, there is
> an
> > unbelievable maze of permits from various layers of government since
> there's
> > a protected marshland as well as habitat restoration within a few miles.
> i
> > think it's safe to say that Sun Quentin could not be built under current
> > rules.
> >
> The ones I have are MDPE (Medium Density Polyethylene) and I haven't
> understood that the plastic would have corrosive features. Obviously it
> can come down to regulation depending on what you use as a cooling agent
> but water is very effective if there is no fear of freezing (I use
> ethanol for that reason). The whole system is closed circuit, I'm not
> pumping water out of the ground but circulating the ethanol in the
> vertical ground piping of approximately 360 meters. The amount of slurry
> that came out of the hole was in order of 5-6 cubic meters. Cannot
> remember exactly what the individual parts cost but the total investment
> was less than $10k. (drilling, piping, circulation, air chiller, fluids,
> etc.) for a system with somewhat over 4kW of cooling capacity. (I'm
> limited by the airflow, not by the ground hole if the calculations prove
> correct)
>
> Pete
>
>
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I believe some of the calculations for hole/trench sizing per ton used for geothermal exchange heating/cooling applications rely on the seasonal nature of heating/cooling. <br><br>I have heard that if you either heat or cool on a continuous permanent basis, year-round, then you need to allow for more hole or trench since the cold/heat doesn't have an off-season to equalize from the surrounding earth.<br>
<br>I don't have hard facts on hand, but it might be a factor worth verifying.<br><br><div class="gmail_quote">On Wed, Mar 26, 2008 at 2:23 AM, Petri Helenius <<a href="mailto:petri@helenius.fi">petri@helenius.fi</a>> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div class="Ih2E3d"><br>
Paul Vixie wrote:<br>
><br>
> aside from the corrosive nature of the salt and other minerals, there is an<br>
> unbelievable maze of permits from various layers of government since there's<br>
> a protected marshland as well as habitat restoration within a few miles. i<br>
> think it's safe to say that Sun Quentin could not be built under current<br>
> rules.<br>
><br>
</div>The ones I have are MDPE (Medium Density Polyethylene) and I haven't<br>
understood that the plastic would have corrosive features. Obviously it<br>
can come down to regulation depending on what you use as a cooling agent<br>
but water is very effective if there is no fear of freezing (I use<br>
ethanol for that reason). The whole system is closed circuit, I'm not<br>
pumping water out of the ground but circulating the ethanol in the<br>
vertical ground piping of approximately 360 meters. The amount of slurry<br>
that came out of the hole was in order of 5-6 cubic meters. Cannot<br>
remember exactly what the individual parts cost but the total investment<br>
was less than $10k. (drilling, piping, circulation, air chiller, fluids,<br>
etc.) for a system with somewhat over 4kW of cooling capacity. (I'm<br>
limited by the airflow, not by the ground hole if the calculations prove<br>
correct)<br>
<br>
Pete<br>
<br>
</blockquote></div><br>
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