[Greenbuilding] Solar microFIT installations (was re: 10 kW solar power plant production)
Mike Neaton
mike at enterspacemn.com
Tue Aug 2 18:33:31 CDT 2011
Could I please be Removed me from your e-mail blast. Thanks Mike
Mike Neaton
EnterSpace
4306 Bryant Avenue South
Minneapolis, MN 55409
612-285-9635 Office
612-929-6006 Fax
612-226-3801 Mike's Cell
-----Original Message-----
From: greenbuilding-bounces at lists.bioenergylists.org
[mailto:greenbuilding-bounces at lists.bioenergylists.org] On Behalf Of RT
Sent: Saturday, July 30, 2011 3:52 PM
To: greenbuilding at lists.bioenergylists.org
Cc: SB Yahoos
Subject: Re: [Greenbuilding] Solar microFIT installations (was re: 10 kW
solar power plant production)
On Sat, 30 Jul 2011 09:57:35 -0400, Frank Tettemer <frank at livingsol.com>
wrote:
> Keith Winston keith at earthsunenergy.com
>> Just for reference: normally on single-axis tracking collector systems,
>> the axis is E-W, not N-S. Are you CERTAIN it's N-S? Also, single-axis
>> is generally good for more like 20% performance improvement, not
>> 30-40%. But at those far north latitudes it may be that my rules of
>> thumb suck (terrible pun on thumb-sucking, for those who missed it).
> The Dager tracker is a single pole mount, holding 10kw, mounted on a
> monstrous concrete base
> My wife and I have built and installed our own microFIT, using eight
> steel poles, no tracker. These mounts can be adjusted seasonally, to
> optimize production but definitely have a production curve that begins
> low in the morning, goes to full production mid-day and drops off in
> afternoon.
I would venture if one were to think about Keith's statement, (horizontal
pipe oriented with long axis oriented East-West) his question would answer
itself.
As mentioned in my response to Reuben's post the other day, the panels
are attached to spars (4 panels per spar, not two as I had mentioned
earlier in my response to Reuben's message) mounted perpendicular to the
long axis of the pipe.
If the long pipe were in fact oriented East-West and if the panels were
laid flat (ie no seasonal tilt), in the morning the panels would be aimed
at the Southern horizon. Then as the pipe rotates, after a ~90 degree
rotation, the panels would be aimed straight up, perpendicular to the
Earth and then after a further 90 degree rotation of the pipe, aimed at
the Northern horizon... which of course, makes no sense.
WRT Keith's comment about Kanata being at "those far north latitudes" ...
my and my neighbour's (rural) Kanata location is at ~ 48.38 degrees North
Latitude, practically within (but not quite)the Banana Belt of Canada,
hardly the "Far North". "North of 60" is probably what most MooseHuggers
would consider "Far North".
*
As I've mentioned on numerous occasions, I have pretty much zero interest
in active solar (and that would include PV gizmology) so I know about that
much (ie ~zero) about PV paraphernalia.
What I do know is that the Dager system with a 10 kW array mounted on a
single pole (as described by Frank) sounds like a nightmare waiting to
happen. I certainly would not care to have one anywhere near my home,
regardless of how many govt incentives there may be, unless of course, one
enjoys having to pick up the bits and pieces of the smashed array at least
a couple of times every year, for the life of the installation (or until
the insurance companies put you on their blacklist).
Even the first design for my neighbour's 10 kW array struck me as being
ill-considered (horizontal pipe suspended 3 m (10 ft) in the air, mounted
atop three vertical single pipes (steel well casings) planted 3m deep into
the ground.
Fortunately, the design was changed to tripod supports at the ends and an
inverted VEE support at the middle so that the support structure is not
unlike that for childrens' playground swings.
As for the skepticism/doubts about the "up to 40% incremental production
over identical but fixed-mount array" in the same neighbourhood, it seems
that my memory was wrong (as it was about some of the physical details of
the revised design).
Some days during winter, it was actually producing 44% more than the
Enphase array.
I did quiz my neighbour about what the daily output curve for his array
looked like and (IIRC, the email exchanges must be on one of my other
computers ) he mentioned that it hit the peak almost as soon as the panels
go on-line in the mornings (as compared to a gradual build-up to a peak at
noon as would be the case for a fixed-mount array (as Frank describes for
his fixed array).
Clearly, the benefits to have an array that tracks the sun over the course
of the day is immensely beneficial however, IMO having that tracking done
automatically with sophisticated controls and equipment
while nifty, is unappealing to me. Just more potential for failures and
expensive fixes IMO. If I were doing it, I think I'd look at trying to rig
up some relatively low-tech mechanical arrangement, perhaps not unlike the
way people used to wind-up clocks every day, with an automatic-default,
spring-back to "12 noon" orientation for those occasions when there's no
one around to "wind up the clock".
I have put some images of the rig along with some relevant comments
snipped from emails, into a PDF file "LlamaRanch PV" that I'll put into
the FILES section, into the "Mechanical (and non) Systems" Folder at the
YahooGroups SB-r-Us site.
For those who are not or can't be bothered to become members of the
SB-r-Us List, if you send me a message *OFF-LIST*, (repeat OFF-LIST)
paying attention to the instructions in my signature file) I'd be willing
to send out the PDF file as a bulk email once all the requests are in. And
if that's not perfectly clear, do not send your request for the PDF to the
List and do not send a message to the List saying that replying to my
edress results in your message being bounced. Such messages will be
ignored. Hokay ? Hokay.
--
=== * ===
Rob Tom
Kanata, Ontario, Canada
< A r c h i L o g i c at Y a h o o dot c a >
(manually winnow the chaff from my edress if you hit "reply")
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