[RE-wrenches] PVWatts Module Temperature Coefficient

[Joel Davidson]

Dave,
Thank you. PVWatts does not predict accurately Unisolar (-0.21%/degC) or 
Sunpower (-0.38%/degC) or Sanyo HIT
( -0.336%/degC). In Los Angeles, I measured 6% more annual kWh from Unisolar 
over a 3 year period and over 10% more from Sunpower so far this year.
Joel Davidson

----- Original Message ----- 
From: "Dave Click" <daveclick at fsec.ucf.edu>
To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
Sent: Monday, April 19, 2010 7:01 AM
Subject: Re: [RE-wrenches] PVWatts Module Temperature Coefficient (was 
Enphase derate)


> It seems to be -0.5%/degC:
> http://rredc.nrel.gov/solar/calculators/PVWATTS/moreabout.html
>
>
> -------- Original Message --------
> Subject: [RE-wrenches] PVWatts Module Temperature Coefficient (was Enphase 
> derate)
> From: Joel  Davidson <joel.davidson at sbcglobal.net>
> To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
> Date: 2010/4/18 12:23
>
>> Wrenches,
>> PVWatts does not accurately predicate Unisolar and Sunpower module
>> performance because it uses a generic single crystal silicon solar
>> module power temperature coefficient (I think -0.4% per degree C). Does
>> someone have the technical paper that specifies PVWatts module
>> temperature coefficient? Thank you.
>> Joel Davidson
>>
>>