SB's in high temperature (was lemmings) [RE-wrenches]

[Tom Lane, Energy Conservation Services]

at what temperature setting ??? do you derate for humidity or dry conditions
is  there a temperature humidity scale for say 95 f-- 15% humidity and 95f
and 85% humidity   HUMID conditions cool better??? or dry conditions --gator
tom
----- Original Message -----
From: <jberdner at sma-america.com>
To: <RE-wrenches at topica.com>
Sent: Thursday, February 06, 2003 7:11 PM
Subject: RE: SB's in high temperature (was lemmings) [RE-wrenches]


> Joel:
>
> UL established the power rating our inverter at 2500 Watts.
> You can certainly design the system around 2200 Watts and it will run
> just fine.
>
> I am a member of the Standards committee at UL and we are proposing
> changing to UL 1741 the way power ratings are established to make power
> rating better reflect real world conditions.  This will give us a level
> playing field for inverter power ratings (for both grid tied and off
> grid) that better reflects the needs of customers.
>
> If you have any questions, or if I can be of any further assistance,
> please do not hesitate to contact me.
>
> Best Regards,
>
> John Berdner
>
> SMA America, Inc.
> 12438 Loma Rica Drive, Unit C
> Grass Valley, CA  95945
> 530.273.4595 (voice)
> 530.274.7271 (fax)
>
>
> -----Original Message-----
> From: Joel Davidson [mailto:joeldavidson at earthlink.net]
> Sent: Thursday, February 06, 2003 3:05 PM
> To: RE-wrenches at topica.com
> Subject: Re: SB's in high temperature (was lemmings) [RE-wrenches]
>
> John,
> I think you will sell just as many Sunny Boy inverters if you rate them
> 2.2
> kW instead of 2.5 kW.
> Best regards,
> Joel Davidson
>
> jberdner at sma-america.com wrote:
>
> > Graham:
> >
> > While you can use the Sunny Boy + Breeze scenario there is another
> more
> > conservative approach is reliability and longevity are of paramount
> > concern.
> > If you undersize the array by 10 to 15% there should be no issue at
> 103
> > F.  This approach adds no additional hardware and not pushing the
> > inverter to its limits will certainly extend it's life. There is a
> rule
> > of thumb in power electronics (I forget who's rule it is) - for every
> > 10C decrease in temperature the life is doubled. This is true for all
> > power electronics not just our inverters.
> >
> > Fan Life - In building the Sunny Breeze we selected a fan with 30 k
> > hours MTBF.  The 2 to 3 year estimate for life is out estimate for
> > outdoor, unprotected mounting.  If mounted indoors it will run more
> > frequently but the life of the fan should certainly be well beyond the
> > warranty period.
> >
> > If you have any questions, or if I can be of any further assistance,
> > please do not hesitate to contact me.
> >
> > Best Regards,
> >
> > John Berdner
> >
> > SMA America, Inc.
> > 12438 Loma Rica Drive, Unit C
> > Grass Valley, CA  95945
> > 530.273.4595 (voice)
> > 530.274.7271 (fax)
> >
>
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