[Greenbuilding] PV Tracking

[RT]

WatJohn and I have a mutual friend (Don Fugler) here in Ottawa , now  
retired, who used to pedal to and from work every day, year round.

In winter, those bike trips both ways would be in the dark ... the sun not  
yet having risen in the mornings (7-ish) and already long gone in the  
evenings (4:30-ish).

OTOH in summer the northeastern sky will often be a spectacular blazing  
red in the hour before 6 am and I remember many June nights working  
outside until almost 10 pm without having to use artificial light.

The Unbelieving Heathens on this List were having trouble swallowing the  
production figures for my neighbour's 10 KW single-axis tracking array.  
Well, those UHs are probably going to gag on the following which came from  
a person whose company has just brought their dual-axis tracking system  
out of R&D and put it on-line.
(I don't know him personally (but I did meet his partner when he was out  
pitching their single-axis system and my SlipperySalesDevil hackles were  
activated) so I can't vouch for the veracity of his claims as I would for  
those of my llama-rancher neighbour.

================= Forwarded material ==================

Sent: Wednesday, June 22, 2011 7:10 PM
Subject: Weekly update...

This is an excellent day for [partner] and me because our first dual-axis  
has been tracking perfectly for 1 week
<snip>
  As my wife transcribed for me last week, we have no idea how effective  
our system is going to be, but for an astonishing figure, our first  
dual-axis has produced an average of 134 Kw per day over the last 3 days  
and even 38 Kw today as of 4pm in all this cloud cover and rain. These are  
amazing figures that NO COMPETITOR can touch.
<snip>

=============== End of forwarded material ===============
(Presumably those are "kWh" not "kW" and yes, I too am having a bit of  
trouble swallowing some of the above ...the bit about the competition, in  
particular)

On those June days, my llamaRancher neighbour's single-axis array was  
producing in the neighbourhood of 100 kWh per day, roughly 40% better the  
the nearby Enphase fixed array.


On Thu, 04 Aug 2011 08:09:25 -0400, jfstraube <jfstraube at gmail.com> wrote:

> PVwatts.org is a wonderful website calculator for PV output that I use  
> all the time.
<snip>
> In Ottawa, it predicts a full 2-axis tracker will produce 36% more  
> electricity than ideally sloped fixed system. I beleive it.
>
> On 2011-08-04, at 7:05 AM, Haudy Kazemi wrote:
>
>> When most people use the power output calculators/estimators,
>> they look at the annual production figures not the daily figures.

>>  A tracker in a high latitude may make larger differencein the summer  
>> than in the winter because the arc of the sun is longer,

>>  A fixed array in those conditions will self-shade in the early and  
>> late parts of the day.  This may the root of the daily difference  
>> between the reported performance difference between the tracked and  
>> non-tracked array.

>> During summer, tracked array may outproduce the non-tracked array by  
>> the ~40% reported in this discussion thread.
>> During spring/fall, tracked array may outproduce non-tracked array by  
>> 20%.
>> During winter, with a short arc, tracked array may outproduce  
>> non-tracked array by 5%.
>> On an annual basis the tracked array may only exceed the non-tracked  
>> array by ~20%, even it does better than that in the summer.
>>
>> Perhaps someone can check this in a calculator?
>
>> On 8/3/2011 8:00 PM, Nick Pyner wrote:
>>>
>>> I just think nobody is taking the geography in to account.
>>>
>>> There are plenty of PV installations around here , but I have never  
>>> seen or heard of a tracking one. This is probably because there is no  
>>> point in them. The situation could  be quite different in the more  
>>> frigid parts of the world for two reasons.
>>>
>>> 1. Even in what is laughably called the banana belt of Canada, the  
>>> insolation is not that great, and the skies are not so clear, so you  
>>> would need to chase every watt you can find.
>>>
>>> 2. In the summer, the days are longer. Hence the practical window of  
>>> opportunity may be as much as an hour wider, but the hourly march of  
>>> the sun is the same.
>>>
>>> A tracking system helps in both cases, and this heathen would imagine  
>>> the more polar you get the more sense a tracker will make.
>>>
>>> Nick Pyner
>>>
>>> Dee Why   NSW (Australia)
>>>
>>> -----Original Message-----
>>> From: greenbuilding-bounces at lists.bioenergylists.org  
>>> [mailto:greenbuilding-bounces at lists.bioenergylists.org]On Behalf Of RT
>>> Sent: Wednesday, 3 August 2011 2:59 PM
>>>
>>> I told him that I had been telling people (this List) that his  
>>> single-axis tracking array had produced 40 and sometimes 44% more than  
>>> the Enphase fixed array and that you (the Listmembers) were telling me  
>>> that I was full of $#!+.
>>>
>>> We both just shrugged our shoulders (as if to say "Nyeh! What can you  
>>> do about  unbelieving heathens ?")


-- 
=== * ===
Rob Tom
Kanata, Ontario, Canada
< A r c h i L o g i c  at  Y a h o o  dot  C A >
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