Insulation of underground pipe [RE-wrenches]

[Dana Orzel]

Wirsbo PEX comes with an insulated cover if desired up to 1 1/2" I think.
Not cheap but deffinitely areal fine system. I have also run 185 foot each
way and set the pipe on blocks and had a spray foam company come and cover
the pipes and then covered it with plactic to reduce diredt water
percolation downward.
Energetically - Dana
Great Solar Works
.
----- Original Message -----
From: jay peltz <jay at asis.com>
To: <RE-wrenches at topica.com>
Sent: Wednesday, August 22, 2001 11:58 AM
Subject: Re: solar thermal pumps [RE-wrenches]


> Hi Jeffrey,
>
> In regards to insulating the pipe.  I have used a pipe in a pipe system in
the
> past.
>
> If you are using say PEX pipe, then install the insulation around the
pipe,
> then install a second ( usually PVC) pipe around this, glue up then
install in
> the ground.  The biggest heat loss is due to moisture pulling the heat
away.
>
> If you have other ideas I'd like to hear them,
>
> jay
>
> Peltz power
>
> "Jeffrey Wolfe, Global Resources" wrote:
>
> > Our experience with glycol (we've standardized on DowFrost / DowTherm at
> > 60%) is that is DOES slush, but that the March pumps we've been using
will
> > pump it when the day warms up. The hardest part to get moving can be the
> > underground piping (no sunshine on it), but the underground in our
systems
> > has always received heat from the house basement, so the worst pipes are
in
> > the spaces behind the collectors.
> >
> > I believe that pushing this cold slush does wear the brushes faster,
> > resulting in more maintenance.
> >
> > If a DC pump must be used, seriously look at Windy's. If you must go
> > brushless (and I understand...) then you really must go AC.
> >
> > The advantage of PV direct seems to fad on the larger systems. As the
size
> > increases, having one controller doesn't seem like a big added
complexity.
> >
> > Pipe all the collectors in parallel as Smitty says. They'll give you
more
> > BTU. Otherwise you're heating progressively hotter water in each
collector,
> > cutting efficiency in each one.
> >
> > Provide some means to balance the system. Parallel piping loops can
create
> > sections that get no flow. Arrange the collectors in say two banks of 3
> > collectors, with globe valves on the return from each section. Set these
> > return valves so that you get equal temperatures from each collector set
> > (therefore equal flow).
> >
> > The piping should be minimum 1". The 3/4" would be good up to MAYBE 3
> > gallons per minute, but that's high with glycol. The bigger pipe does
have
> > the disadvantage of more fluid, longer travel time, etc., but that can
be
> > overcome with a little extra insulation. (Insulation is cheap,
collectors
> > are expensive.) So run 1" out to the panel location, then feed each bank
of
> > 3 collectors with 3/4".
> >
> > Bury the pipes in an oversized smooth wall drain pipe. Pitch this pipe
back
> > to an open drain. Buried piping either costs about $200 PER FOOT, or it
> > gets water in it. Since ours always costs less than $200 per foot, we
give
> > the water some place to go, rather than sitting in the pipe and
insulation.
> >
> > Good luck.
> >
> > Jeff
> > ----------
> > From:   Smitty[SMTP:smitty at aaasolar.com]
> > Reply To:       RE-wrenches at topica.com
> > Sent:   Tuesday, August 21, 2001 11:38 AM
> > To:     RE-wrenches at topica.com
> > Subject:        Re: solar thermal pumps [RE-wrenches]
> >
> > Kurt, for what it's worth, Richard Lane and I have conducted some tests
> > of various pumps moving glycol and water at the large Packerland system
> > (R.I.P.) in Green Bay. I am assuming this system is going to be in
> > northern Wisconsin. What we found is that in the dead of winter, with
> > very low temps, the glycol will start slushing and even become a
> > semisolid ice plug, but not enough to pop anything. At daylight the
> > panels tend to thaw out, but the glycol in the insulated above ground
> > plumbing remains semi frozen or very thick. The DC pumps we tested had a
> > very tough time with this. Sorry Dan, but the El Cid just didn't cut it
> > with semi frozen glycol. The Hartell did a bit better but in the final
> > analysis I would use an AC pump and a differential controller if
> > possible. A few days of the year, we would even have problems with the
> > Packerland system, and that was with 6"-14" pipes and many 10 hp pumps
> > (5000 collectors). If you go DC, I would oversize the PV panel to
> > accommodate morning incident angle, so it at least it has chance of
> > getting the glycol moving.
> >
> > The panels should be plumbed in parallel.
> >
> > The smaller a pipe is, the more frictional wall loss there is. 3/4" is
> > the smallest I would use. Hope this helps. Smitty.
> >
> > Kurt Nelson wrote:
> >
> > > Greetings all (and Smitty?), I'm doing a solar thermal system/in-slab
> > > hydronics, and though I have done a number of SDHW systems, I'm new to
> > > moving fluid through larger arrays. The collector is 5  (possibly
> > > six), 4x8 Solar Kings ground mounted about forty feet from the house.
> > > I would like to run the pump(s) PV direct and it would seem that there
> > > is a shortage of pumps to choose from here.  I was thinking two Hartel
> > > HEH-10's (did I get the model numer right) and would welcome other
> > > suggestions.  Also, .... 1 - Is it best to plumb (pipes) them in
> > > series, or parallel?2- Is it best to wire them each to individual
> > > 18-22 watt panels (my guess) or both to a single 38 to 44 watt panel.3
> > > - The burried and insulated piping from the array to the house....  go
> > > with 3/4 inch pipe (or even larger) to accomidate flow, or 1/2 inch to
> > > reduce heat loss from piping surface area AND the increased time the
> > > heat transfer fluid spends in the pipe? Thanks in advance for thoughts
> > > and suggestions.Kurt NelsonSOLutions
> > >
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