Sunny Boy in the sun? [RE-wrenches]

[John Berdner]

Gary / Wrenches:
 
The direct sun question is one we get all the time.
Our manual says do not mount the inverter in direct sunlight. 
If the inverter is in direct sunlight then use a shade over the
heatsink or use a fan.
That being said I do not want to rule out ever mounting an inverter on
the South or West wall.
Every installation is different so blanket statements can't apply - use
good judgement.
Matt L.'s post is right on the money in this regard.
 
We suggest:
Mount the inverter in the shade whenever possible.
Ideally on the North or East side of a building.
You can also mount them on the roof under an array if you have 10" or
so above the heatsink.
In all cases airflow is MUCH more important than ambient temperature as
far as derating is concerned.
If you run it at < 75% of rated power it will probably work pretty well
with sun on it.
If you have to put it in the sun put a fan on it or put up a shade
structure.
If you don't have a fan or shade in full sun then your customer will
probably be crying the 12 bar derating blues. 


 
Bottom Line: 
UL requires us to limit the heatsink to 70C under all conditions.
If the heatsink gets up above 65C then you will start to have some
derating going on.
Every system / installation is different so take out your calibrated,
mark 1 palm and press it against the heatsink in the hottest part of the
day.
If your hand gets uncomfortable then it is probably too hot and needs
some shade or a fan.
 
Best Regards,
 
John Berdner

>>> gary at windstreamsolar.com 9/26/2003 11:16:11 AM >>>
Wrenches,

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?

Thank you,

Gary

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Gary Higbee ( gary at windstreamsolar.com )
(541 )607-1818 (Eugene)
(541) 954-3881 (Cell)
Solar, wind, and hydro site analysis and system design
Components dealer and installation assistance
Energy Trust of Oregon contracted system inspector
~ WindStream Solar ( www.windstreamsolar.com ) ~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~



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