Tubular towers and PV mounting [RE-wrenches]

[Ian Woofenden, Home Power]

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Jeff,

Thanks for your good advice. We will most certainly be getting 
engineering done for a project of this size and scope. We're looking 
at a freestanding (non-guyed) tower.

Matt,

The tower cost for this project will probably be half the system cost 
-- a major chunk of change. But it will let the customer capture two 
resources -- sun and wind.

Ian

>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
>61 Baker Road
>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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-- 

Ian Woofenden <ian.woofenden at homepower.com>, Senior Editor
Home Power magazine, The Hands-On Journal Of Home-Made Power
My use of words is just some antics.

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