Thin film expansion

stephendv
stephendv Solar Expert Posts: 1,571 ✭✭
in Off Grid Solar & Battery Systems #1
Just finished installing and connecting up 1.6kW of Sharp NAF-121 panels. They're tandem junction "micromorph" panels, with one layer of amorphous silicon and another layer of micro-crystaline silicon giving them a 9% efficiency. So they're more efficient than plain amorphous panels, but less efficient than poly panels.

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Because of the amorphous layer they're subject to the Staebler–Wronski degrading effect, so the initial rating is 140W which will then degrade to their STC rating of 125W, they come with the standard 80% over 25 year warranty and a 10 year manufacturing warranty from Sharp.

Paid 0.33 Euro/Watt for them in Germany, adding in shipping costs, they came in at about 0.43 Euro/Watt ($0.55/Watt). They're an "old" model, so got them at the price because the supplier was clearing stocks.

I have a lot of roof space, so the efficiency isn't really that much of a concern, all I really care about is Price/Watt in cloudy weather. The existing Yingli panels have done a great job of supplying enough energy during most days and we've only had to run the generator about 15 hours for the whole year. I also plan to increase the loads with more water pumping, hot water heating and perhaps some LED grow lights, so the additional PV is really for opportunity loads and to see us through cloudy days.

I'll be really pleased if we can reduce the gen runtime to 0 through good load management and of course the added capacity of these new PVs.

The mounting structure is the "singlefix" system from Schletter which uses short 45cm mouting rails screwed directly to the sheet metal roof.

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It was really easy and fast to fit since it uses self-drilling screws so the whole structure can be mounted from on top of the roof without having to connect nuts and bolts underneath the beams.
There's a video of the mounting system here: http://www.youtube.com/watch?v=nJj8LGxRmxE
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Comments

  • NorthGuy
    NorthGuy Solar Expert Posts: 1,913 ✭✭
    #2
    Re: Thin film expansion

    Nice install. The panels look very good on the orange roof.
    stephendv wrote: »
    I have a lot of roof space, so the efficiency isn't really that much of a concern, all I really care about is Price/Watt in cloudy weather.

    Is that simply because they're cheaper, or are they more efficient in the cloudy weather compared to full sunlight?
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #3
    Re: Thin film expansion
    NorthGuy wrote: »
    Is that simply because they're cheaper, or are they more efficient in the cloudy weather compared to full sunlight?

    They do better in full sunlight than cloudy weather, but in cloudy weather they may do better than poly or mono crystal panels. --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #4
    Re: Thin film expansion
    NorthGuy wrote: »
    Is that simply because they're cheaper, or are they more efficient in the cloudy weather compared to full sunlight?

    As vtmaps said, they should be better than poly/mono under cloudy weather _and_ they were cheaper. Will have to wait until they degrade to their rated STC value before I can do a fair comparison with the poly's.
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #5
    Re: Thin film expansion
    stephendv wrote: »
    As vtmaps said, they should be better than poly/mono under cloudy weather _and_ they were cheaper. Will have to wait until they degrade to their rated STC value before I can do a fair comparison with the poly's.

    Hi, Stephen, very good PV extension, maybe you put at work another midnite??? ...;-)
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #6
    Re: Thin film expansion
    unicornio wrote: »
    Hi, Stephen, very good PV extension, maybe you put at work another midnite??? ...;-)

    Not yet :) The Yingli's are 2.8kW + 1.6kW Sharp so 4.4kW total, but so far I've only seen 3.8kW on the midnite; look forward to seeing what they can do when it cools down a bit.
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  • NorthGuy
    NorthGuy Solar Expert Posts: 1,913 ✭✭
    #7
    Re: Thin film expansion
    stephendv wrote: »
    Will have to wait until they degrade to their rated STC value before I can do a fair comparison with the poly's.

    Looking forward to this.

    I have monos. My temperature adjusted production depends on the insolation linearly. I get about 6.2W from 1W/m2 of insolation. There's no degradation of performance at low light.
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #8
    Re: Thin film expansion
    stephendv wrote: »
    Not yet :) The Yingli's are 2.8kW + 1.6kW Sharp so 4.4kW total, but so far I've only seen 3.8kW on the midnite; look forward to seeing what they can do when it cools down a bit.

    that means you've managed to combine the two arrays with the same midnite? ...wow!...
    at first I thought you have "mobilized" the tristar again ... ;-)
    very good! ... you get to coincided everything okay! ...
    that well with 48v, more flexibility, more capacity ... how many amp can swallows the midnite? ... hehehehe

    yeh!, we have a few days of extreme heat which down the production a lot ... that will have to climb a lot in a good time! ...;-)
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #9
    Re: Thin film expansion

    Yes the sharp's are in parallel with the existing array, this was one of the advantage of those panels, they have a Vmp of 45V and the Yingli's have a Vmp of 29.9V and since I have 3 x Yingli in series, 2 of the Sharp's fit in perfectly. The Midnite should be able to handle 80A at 48V, I've only seen 60A so far.

    Northguy, unfortunately I don't have an insolation meter so will just be able to measure the sharp's relative to the yingli's not relative to insolation.
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #10
    Re: Thin film expansion
    stephendv wrote: »
    Yes the sharp's are in parallel with the existing array, this was one of the advantage of those panels, they have a Vmp of 45V and the Yingli's have a Vmp of 29.9V and since I have 3 x Yingli in series, 2 of the Sharp's fit in perfectly. The Midnite should be able to handle 80A at 48V, I've only seen 60A so far.

    so you have enough with only one midnite...;-)
    well thought out and very well finished ... hehehehe
    how many daily kwh you get?...
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #11
    Re: Thin film expansion

    Average about 7kWh/day, full logs here: https://xively.com/feeds/75889/
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #12
    Re: Thin film expansion

    Took the first readings during a cloudy day:

    Poly: 0.193W/Wp installed.
    Thin film: 0.197W/Wp installed.

    I.e. hardly any difference. To give you an idea of the type of cloud cover, I was seeing 1.11kW from a total of 4.8kWp installed.

    Attachment not found.
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  • NorthGuy
    NorthGuy Solar Expert Posts: 1,913 ✭✭
    #13
    Re: Thin film expansion
    stephendv wrote: »
    Poly: 0.193W/Wp installed.
    Thin film: 0.197W/Wp installed.

    Looks exactly the same to me. However, you still can see the sun, so the angle could matter.
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