[RE-wrenches] Uni-Solar, Kaneka.now Panasonic?

[Exeltech]

Larry,

As August pointed out, there are too many variables related to PV performance to focus on just one and call it "good".  He's right on target.

For a very simplistic example...

One aspect of PV performance relates to cell temperature, which in turn is affected by the NOCT rating of the PV.  NOCT ("nominal operating cell temperature" is an indicator of a PV module's ability to dissipate unwanted heat.  Higher values of NOCT indicate a module that will have hotter cells than PV with a lower value for NOCT (all other things being equal).

Let's say you're comparing two PV that have similar temperature coefficients, but different values for the NOCT.

PV 'A' has a slightly worse temperature coefficient, but a lower NOCT than PV 'B'.

On paper, looking only at the temperature coefficient, it would appear PV 'B" would outperform PV 'A'.

However, in this example, PV 'A' would be operating at a lower cell temperature due to its superior ability to dissipate heat.  The ultimate cell temperatures of PV 'A' may be sufficiently cooler than PV 'B" to allow it to equal or even slightly outperform PV 'B".

Incidentally, NOCT is measured and reported by the NRTL during certification.  The manufacturer simply prints this value in their PV specs.


As with anything .. your mileage....


Dan

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On Fri, 3/14/14, Larry Crutcher, Starlight Solar Power Systems <larry at starlightsolar.com> wrote:

 Subject: [RE-wrenches] Uni-Solar, Kaneka…now Panasonic?
 To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
 Date: Friday, March 14, 2014, 10:33 AM

 Wrenches,

What high performance PV modules are being sold in the US? I can't find Panasonic modules anymore. I have written to them twice but they can't direct me to any distribution in the US. They insist that Sunwize will have them but Sunwize says they have no plans yet to purchase again.

>From what I can tell, the next best thing is Sunpower modules with -0.38% /K temp coefficient. Are there any others to consider?

Larry Crutcher