09 stewart prism solar

Enhanced Bifacial Solar Modules for Next Genera7on Applica7ons

Randy Stewart, CEO Prism Solar Technologies

bifiPV Workshop Konstanz, Germany April 22-‐24, 2012

Who is Prism Solar Technologies?

–  Started in 2005 with a mission to inves7gate techniques in holography and create new opportuni7es in the Clean Energy marketplace.

•  PST has designed, fabricated and field tested a series of enhanced PV modules where holograms aid in sunlight harves7ng.

•  PST has op7mized methods for high volume manufacturing of holograms for Solar applica7ons.

•  PST has introduced to the marketplace, a line of new module products based upon bifacial solar cells.

Prism Solar Technologies

Added sunlight captured by PV

– Holographic film is spaced between rows of PV.

– Holographic film and PV are laminated between two layers of glass.


Sunlight captured by TIR

•  Total Internal Reflec7on allows the hologram and the two layers of glass to act as waveguide for addi7onal energy harves7ng.

•  New design parameters: –  Width of hologram / Width of PV is important –  Angular efficiency of hologram is important –  Thickness of glass becomes important


Prism Solar T-‐120 Product line


Design opportuni7es (or limita7ons) •  Cell size and number of bus bars

–  Width ra7o is important; we cut cells

•  Angular efficiency of holograms –  Holograms op7mized for different moun7ng structures

•  Thickness of glass layers –  Structural a`ributes of glass are important –  Thicker glass leads to greater contribu7on from holograms

•  Efficiency of Solar Cells –  Higher efficiency = greater energy harves7ng

•  Cost of Commercial Solar Cells –  Compe77ve marketplace


Solar Marketplace


Large arrays; poorly defined ground cover.

New Opportuni7es


Smaller arrays; architectural needs

New Opportuni7es


Larger installa7ons; different architectural challenges

Demands of new opportuni7es

•  Addi7onal energy harves7ng at non-‐la7tude angles –  Hologram contribu7on can be tailored to aid

•  Structural a`ributes for building industry –  Thicker glass and adhesive interlayer

•  Designs with useful features for builders –  Posi7on and type of electrical connec7ons –  Frameless modules are more important

•  Enhanced reflec7vity of neighboring surfaces –  Improving bifacial value posi7on –  Example is the Commercial White Roof opportunity


Holograms for enhanced efficiency

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Contribu

)on

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e cell (%

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Ver7cal Hologram

La7tude Hologram


Build & Test Full Size Modules


Primary moun7ng axis

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Power (W

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declina)on (degrees)

Pmax (Low Tilt Hologram)

Pmax (Spaced Bifacial)

Pmax (La7tude Hologram)


La7tude Hologram


Spaced Bifacial Reference Module La7tude Hologram Module

Hologram for Ver7cal Moun7ng


Spaced Bifacial Reference Module Ver7cal Hologram Module

Difference


Yearly Performance of the Hologram for a module mounted ver7cally

Hologram Designed for Ver7cal Moun7ng


Hologram Designed for La7tude Moun7ng

Yearly Performance of the Hologram for a module mounted ver7cally


Hologram Designed for La7tude Moun7ng

Hologram Designed for Ver7cal Moun7ng

Hologram Efficiency v La7tude


•  New opportuni7es for bifacial solar cells –  Improved performance; both front & back

•  Solar module installa7ons are changing – Addi7onal energy harves7ng can be put to work

•  New design parameters to achieve best performance – Structural glass, frameless modules and unique architectural features

•  Cost will always remain important


Thank You


www.prismsolar.com

09 stewart prism solar

Presentations & Public Speaking

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