Silicone structural sealants enable frameless mounting systems: Cost-effective reliable solutions for large scale production

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1 Silicone structural sealants enable frameless mounting systems: Cost-effective reliable solutions for large scale production 5 th SMET, Munich, May 28 Thibault Kervyn

2 Outline PV Framing and mounting systems Silicone structural sealant and structural glazing Requirements Dimensioning & Substrates Practical example

3 PV Framing & Mounting Systems Material U-frame L-frame Rails (mostly for glass/glass) Sealant OR doublesided tape Pads (mostly for glass/glass) Structural sealant Structural sealant Structural sealant Function needed Damping Structural Structural Structural (thick section) Process Performance (Advantages) Frame can be preassembled or supplied as 1-piece Lower risk of dust and water accumulation Easy process Lower risk of current leakage. Allows very large sizes. Easy process Minimum material (cost & weight) Faster installation Double-sided tape OR sealant Glass Back-sheet Structural Sealant Structural Sealant Structural Sealant To the full extent permitted by law, Dow Corning disclaims any and all liability with respect to your use of, or reliance upon, these instructions. You agree that you have the sole obligation to decide whether information provided by Dow Corning will work in your processes or will be safe and efficacious in your applications. It is your sole responsibility to determine the suitability of the information provided to you. DOW CORNING DOES NOT MAKE ANY WARRANTY OR REPRESENTATION, EXPRESS OR IMPLIED, WITH RESPECT TO THE UTILITY OR COMPLETENESS OF THE INFORMATION PROVIDED TO YOU AND SPECIFICALLY DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. DOW CORNING DISCLAIMS LIABILITY FOR ANY INCIDENTAL OR CONSEQUENTIAL DAMAGES.

4 Structural Glazing 1971 First 4-sided SG project which used silicone for full attachment of glass 1984 Two part SG Sealant for faster cure Structural Sealant Weather Sealant

5 BP Exploration Alaska Anchorage, Alaska SEISMIC COLD Wells Fargo Tower Las Vegas, Nevada WIND UV, HEAT Construction Date: 1983 Environment: Frequent, strong seismic activity 3 C Average annual temperature -37 to 29 C extremes 414 mm annual precipitation Installation Date: 1986 Environment: Windstorms from F0 to F2 (up to 253 kph) -3 to 42 C extremes Frequent minor quakes High UV exposure Over 300 days of sunshine on average annually Exchange Square HONG KONG HUMIDITY TYPHOONS Installation Date: 1984 Environment: Tropical heat and humidity Frequent heavy rains and typhoons Degrading effects of air pollution sse Frankfurt Frankfurt, Germany Installation Date: 1986 Environment: Mild temperature Frequent (acid) rains Mild (Acid) RAIN

6 Silicones versus Organics O Si O Si O Si O Si O Si Si O bond: ~110 kcal/mol R1 R3 R1 R3 R1 R3 R1 R3 R1 R3 C C bond: ~80 kcal/mol R2 R4 R2 R4 R2 R4 R2 R4 R2 R4 Silicone properties renowned UV stability and moisture resistance. excellent dielectric properties Silicone performs over a wide operating temperature range (from -40 to 150 C) Flexible, low modulus -> stress relief Very low surface tension (excellent wetting as a liquid, water repellant as solid) Very low vapor absorption -> good protection against water ingress and corrosion Good flammability resistance

7 Standards and Certifications PV Standards IEC 61215/61646: PV Modules Performance Standard Aging, chanical load (2400 Pa), Snowload, Hail Tests IEC 61730: PV Module Safety Standard Fire, Module breakage test Construction Standards ETAG 002: Guideline for European Technical Approval for SSG Kits) ASTM C1184: Standard Specification for Structural Silicone Sealants ASTM C1401: Standard Guide for Structural Sealant Glazing DRAFT

8 Dow Corning brand PV Structural Sealants Dow Corning Brand Products Workin g time Time for handling Comment Dow Corning PV Adhesive 1 part min Depends on thickness > 1 day Long cure time Easy to use Dow Corning PV Fast Cure Sealant 2 part (10:1) min 4 hrs Two part providing customized cure rates Dow Corning PV Ultra Fast Cure Sealant 2 part (10:1 to 10:2) <5 min 20 min Ultra fast Need automation

9 Joint Dimension Windload (2400 Pa under IEC 61215) Bite = Area* Windload BondLength* Max _ allowed _ design _ stress Deadload (laminate weight) Bite = La min ate _ weight Bondlength* Allowable _ design _ stress _ for _ deadload Thermal dilatation (sealant cured at 20ºC, Tmax=90ºC, Tmin=-40ºC) Thermal _ dilatation* Young _ modulus Thickness = 3* Max _ allowed _ stress _ shear Thermal _ dilatation = glass _ length* thermal _ variation*( CTE Al CTE glass )

10 Calculator

11 Substrates

12 H-Piece samples, 21d in 40C Stainless Steel Galvanized Steel

13 OptiBond (Schletter Solar Mounting System ) Static FEM calculation to determine the optimum bonding spots Simulations: Dr. Zapfe GmbH Photos courtesy of Schletter

14 Mounting Time Photos courtesy of Schletter

15 Application and Quality Control Testing summary After each pump start-up After each container change After each substrate change Diagnostic investigation Glass test Required Required - Required Butterfly test Alternative to Glass test Alternative to Glass test - Required Snap Time test Required Required - Required Mixing ratio test Not required Not required Not required Required Peel Adhesion test dry Required Required Required - Peel Adhesion wet Required for anodized aluminium Required for anodized aluminium Required for anodized aluminium - H-Piece test Alternate to peel test Required Alternate to peel test - Deglazing test Only for specific projects Only for specific projects Only for specific projects -

16 Testing Butterfly test Glass test Proper Mix Improper Mix Proper Mix Improper Mix Snap time test

17 Testing Peel test H-piece test Lap Shear test Prototyping Creep

18 Summary Frameless designs can offer significant advantages in terms of material/processing cost, durability and installation time. Silicone structural sealants have demonstrated durability under harsh environment for structural glazing in construction. Dow Corning is committed to developing cost-effective silicone solutions to enable module manufactures to reach grid competitiveness and grow the PV industry!

19 Thank you! The information provided in this presentation does not constitute a contractual commitment by Dow Corning. While Dow Corning does its best to assure that information contained in this presentation is accurate and fully up-to-date, Dow Corning does not guarantee or warranty the accuracy or completeness of information provided in this presentation. Dow Corning reserves the right to make improvements, corrections and/or changes to this presentation in the future.