Tubular towers and PV mounting [RE-wrenches]

[Matt Tritt]

Jeff,

I suggested one of the towers I handle to Ian, which actually is not made by
Rohn, but has their own engineers that calc. everything out. This is
required for each application very specifically. As far as I know, this is
not a guyed tower,. A 160' guyed tower would require a huge amount of room
on the ground for the guys - over a football field from anchor point to
anchor point and since they want to stick this baby in the forest I can't
see how that could work. A free-standing monopole of this height will also
need to be quite massive at the base and have a huge foundation block/pad.

Such a tower will cost considerably more than a 3 kW turbine, not to mention
the installation costs and engineering of the tower and foundation
----- Original Message ----- 
From: "Jeff Clearwater, Village Power Design" <clrwater at earthlink.net>
To: <RE-wrenches at topica.com>
Sent: Sunday, November 16, 2003 8:26 PM
Subject: Re: Tubular towers and PV mounting [RE-wrenches]


> Hi Hugh & Matt & Ian,
>
> Well I'll defer to your judgement, Hugh, as you have much more wind
> experience than I.   I learned about resonance to close to the hard
> way - so I may be overly cautious about it.    However 2-3 KW are
> liable not to be attached at just one point on the tower.  If they do
> go with a guyed tower then you'd probably want to attach a guy at the
> top and bottom of the array attachment points.
>
> And whether it's  freestanding or guyed, I still would still
> recommend at least a phone call to the engineers at Rohn.  They've
> been really helpful to us on such questions.
>
> Best,
>
> Jeff C.
>
>
>
> >At 1:02 AM -0500 16/11/03, Jeff Clearwater, Village Power Design wrote:
> >>With two loads pushing from the side you can get some complicated
> >>resonance action.
> >
> >If the PV array is located at a guy attachment level then the side
> >loading will not be an issue in terms of pipe bending loads.  The PV
> >array will not introduce vibration into the structure either.  All
> >that remains is the mass of the array and its effect on tower
> >resonance.  Once again, if the array is at a guy level then it is
> >hard to see that extra mass at this nodal point would have any
> >significant effect.
> >
> >>- don't guess - hire a structural engineer to stamp this one!
> >
> >I would say it depends on the customer.  It's an extra expense, and
> >in my opinion hardly justified.  But some jobs have plenty of money
> >for that sort of stuff.  It's known as covering your @&5#.
> >
> >If your wind turbine is "maxing out" the tower, then later on
> >someone will be looking for an excuse for failures, but the mistake
> >was to use a turbine that behaves like that to begin with.
> >
> >--
> >Hugh
> >
> >in Edinburgh
> >http://www.scoraigwind.co.uk/
> >
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> -- 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Jeff Clearwater
> Village Power Design Associates
> http://www.villagepower.com
> Sustainable Energy & Water Solutions for Home & Village
>
> Office:  (413) 256-6777,  Cell: (720)480-8455
> Fax:  (413) 825-0372
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> Shutesbury, MA 01072;
> PO Box 115
> Boonville, CA  95415
> (707) 895-9015
> Fax: (707) 897-0224
>
> Council Member - Ecovillage Network of the Americas -
http://www.ecovillage.org
> Advisory Board - Living Routes - Ecovillage Education -
> http://www.livingroutes.org
> Founder:  Ecovillage Research, Development, and Demonstration Program:
> http://www.home.earthlink.net/~clrwater/RDD/rdd.html
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
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