Sunny Boy in the sun? [RE-wrenches]

Fri Sep 26 15:36:21 PDT 2003

Gary H wrote:

> In doing inspections for the Energy Trust of Oregon we're seeing a lot
of Sunny Boys, of course. I'd appreciate your pass on whether we should
allow the units to be mounted on exposed locations in the sun--in
particular West- and South-facing surfaces. At present we lean towards
requiring some sort of sun shade (while still maintaining good air
circulation).

We know about the importance of good air circulation, but what about
significant direct sun and hot ambient temperatures?

What's your pass? Has anyone done a test to see what derating occurs?
Should we allow unshaded Sunny Boys on these surfaces or not?

-Gary

Gary / Wrenches:

There are a couple of things Gary is asking, if you're asking me.... I
know nobody did, but....

First of all, I'm with Mo R in that SMA should, and I believe will,
weigh in here.  Secondly, Max B's answer simply won't work everywhere
for everybody.  It is extremely commendable in its intent and effort.
Max's local extreme heat isn't necessarily the case in Oregon and
placing the inverter in the environmentally conditioned space adds heat
to that space.  Does that heat add up to more cooling load than the
"lost kWH" from "derating"?  I don't know the answer, and don't have the
formulas handy, but it's gotta be something.  

I have personally seen and "dealt with" the "de-rating" issue on at
least 50 systems in the last two years.  I say 50 just to be
conservative.  None of them have "dropped dead" from the heat yet!

The real essence I get from Gary H's question is this:  He is acting as
an inspector in this capacity.  A third-party expert.  The results and
opinion(s) he has about the systems he inspects eventually lead to two
primary things.... An incentive payment or not and, perhaps FAR more
importantly and long-reaching, POLICY.  Gary is asking a question
because he wants to do the most responsible thing he can.... Probably
for the end-user, Industry, and future of the Industry at least in
Oregon.  Thank you, Gary, for caring enough to ask!

I can answer most of the "end-user" part of that from experience and
production data.  That part is the "productivity" issue.  The answer is
that, here in the Sacramento area (Not as hot at the Coachella Valley,
but hotter than a lot of places!)  no measurable or discernable kWH
production trends are found in otherwise comparable systems.  FACT!  It
is a factor we are monitoring and looking for, by the way.

Another "wildcard" is "What the Customer is expecting".... Salespeople
promise anything.  Well-intentioned or not.  On top of that, it's not
"What you told them" that counts.... It's "What they heard"!!!!!!
That's a big one and every single one of us should be sensitive to and
understand it.  Please be ethical!!!!!

The other part of the equation is the cumaltive "life-expectancy" of the
inverter and its accessories. (Like blackened LCD Displays...Which does
occur when they are in the heat.  Most, if not all I have visited later
display accurately when in the cooler parts of the day.  Your calculator
will do the same thing if you leave it on the dash.) 

"How much of the effective inverter life is lost by being exposed to
direct sunlight?" is what it all comes down to.

In order to truly answer that question, we will have to conduct at least
a 15 year study.  That study will require, among many other things, a
sample quantity of inverters on comparable systems, in various exposure
settings.  (Compare an inverter mounted in a garage, another inside a
conditioned space, another on the north side of a house, another on the
south, another on the south with partial shade, another on the south
with full shade and good airflow, another on the west, with and without
shade, etc.  Oh, by the way, the arrays will all have to be comparable,
too!  Multiply that by at least 20 to get even the most basic element of
scientificity!) 

I don't think this Industry can wait 20 years, personally.  I'm gonna
live to be 100 and Alive.  That's my "life expectancy".  It's those
"unexpected" things that will more than likely get in the way of that.
Like maybe a Mack Truck vs. my motorcycle!

Back to Gary H's issue.... Policy and End-User Value.  Since some agency
is disbursing funds, as an investment in our Industry, those funds must
be disbursed fairly and in the most reasonable and justifiable manner
possible.  That is one element of "free money" that many don't fully
understand, but it comes at a cost and, at least in Gary's case, he
cares enough to ask.  How many inspectors do you know who even bother?

Think about it this way:  If Gary goes back to the Energy Trust and says
"No Sunny Boys in the Sun", that will lead to a policy of "No inverters
in the Sun, EVER!"   A blanket policy like this will put things in
people's minds that may not be easily overcome.  The word will spread
among local building inspectors.  Instead of looking at the real things
that matter, like properly wired and safely installed systems, some of
them will walk up, see that there is a potential for the inverter to
"see the light of day" and that will be "it".  That's a FACT.  I don't
believe that's a prudent course.

This brings up a couple of Manufacturer's-Please-Support-Us issues.  We,
as Wrenches, need the Manu's to include Clear and Definitive
recommendations and guidelines in their Installation Manuals to address
this and other topics.  If there is something like "Not in the direct
Sun", then have a reasonably priced "accessory" available for those
applications.  This makes it easier for the Designer/Installer, promotes
Branding, and makes it easy for the Building Inspector!  It will also,
IMHO, make it easier for the Manu.

I don't have a "definitive" answer to Gary's question so I'll quantify
it like this and hope for the best in Oregon!

My personal bottom line is this:  Do your best, with all the Site
Circumstances considered, to put those inverters in the shade... For
some "unquantifiable at this point insurance", if nothing else.  Just
instinct based on experience.  Be honest with your Customers about your
concerns.  You'll find that, ultimately, you end up selling more systems
and getting to install them "your way" with less problems.  One of the
reasons is simply that "The Customer who is going to buy from the
Sales-Slick is going to buy from them anyway."  Those are the Customers
that honest, hard-working, believing, real Wrenches don't want.  They
are headaches!

PS - My gut feeling is that Max B's inverters will last longer and
generate "more kWH's per Inverter" than one installed in the direct Sun.

Two Cents and.....

Sunshine!

Matt Lafferty
Universal Energies Institute
mlafferty at universalenergies.com
(916) 422-9772
(916) 628-7694 Cell
(916) 914-2247 Fax
www.universalenergies.com

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