IN-DEPTH: Glass maker cuts it

Jun 20, 2009

Guardian believes leading-edge technology only comes to markets where global players maintain a direct presence

By CSP Today staff writer

Glass manufacturer Guardian Industries recently showcased its EcoGuard Solar Boost laminated product for concentrating solar power at the CSP, CPV and Thin Film Technology Summit MENA in Abu Dhabi.

The company, which has glass manufacturing plants in Egypt, Saudi Arabia and Ras al Khaimah (RAK), UAE, believes there are significant opportunities in all areas of value-added glass in the region, especially for solar energy related products.

Guardian views the Middle East & North Africa (MENA) region as a strategic growth area for the company.

“With the installation of our state-of-the-art coating facility in RAK we are now capable of offering our customers full service from within the region,” said Scott Thomsen, CTO and VP, Guardian Industries’ Science & Technology Center .

In the past customers had to rely on Guardian imports from Europe or North America to satisfy some of their business needs.

“We will align our local product strategy to our asset base in the region. Our long-term goal is to produce products locally and not rely on imports to meet our customer needs,” Thomsen added.

Growing presence

The company is using its offering for the CSP industry to expand its presence in the region.

In key regions around the world, Guardian manufactures EcoGuard Float, a low-iron float glass designed to maximise solar energy transmission in a variety of applications, EcoGuard Solar Boost monolithic parabolic mirror and EcoGuard Pattern, a low-iron pattern glass designed to maximise solar energy transmission.

Guardian’s EcoGuard Solar Boost Laminated and Monolithic Parabolic Mirrors utilise its highest performing solar glass, EcoGuard Float, for solar reflectivity and durability.

Designed specifically for CSP parabolic trough systems, EcoGuard Solar Boost laminated mirrors are available in standard RP-2, 3 and 4 design configurations and are direct bolt-in replacements for the traditional monolithic configurations.

Efficiency through choice

Offering optimal energy and light transmission, EcoGuard Float is used for CSP mirrors, solar thermal applications and other areas where high transmission is required, the company says. EcoGuard Float is available in several transmission ranges and thickness from 0.95mm to 12mm.

Guardian EcoGuard Float is offered in four solar transmission ranges to allow energy customers to tailor the glass performance to their application.

“Rather than adopting a take-it-or-leave-it approach, we felt it made better business sense to develop a range of solar transmission options that are aligned with the dollar-per-watt expectations of the customer application,” Thomsen said.

“Why use 90.8% Tsolar 4mm glass when the cost/benefit does not support the purchase price? Guardian EcoGuard Float is a true low iron glass with a total iron content less than 0.010.”

The company says EcoGuard Float maintains its solar transmission throughout its useful life. Guardian does not incorporate oxidising agents such as CeO2 that exhibit solarisation: reduction in transmission over time due to UV exposure.

Challenges mirrored

The challenge for the glass industry is to contribute to progress in CSP technology, to reduce the weight of the mirror assemblies and to increase solar reflectance.

Another advancement will be the incorporation of first-surface mirror technology on glass to further increase solar reflectance. To date, metal mirrors have been demonstrated on a prototype basis but have yet to be installed in CSP fields.

Thomsen reasoned that First Surface Mirror (FSM) technology had not yet been adopted for CSP large scale fields owing to lack of environmental durability.

Guardian is currently a large-scale producer of FSM technology for the electronics industry.

“We are exploring options to transfer our technology to the CSP application but realise the technical hurdles are rather high at this point in time. We continue to do research and development in this area,” said Thomsen.

Technology and component standardisation is a paradoxical issue. On the one hand standardisation allows component manufacturers to focus on a limited product range and therefore reduce costs for the buyer. On the other hand that same standardisation could become an obstacle to technology and efficiency improvements; since the cost of these “prototypes” would be much higher (at the beginning) than for a standard product.

Thomsen pointed out that numerous CSP technologies were all competing for business, and in future, there would be winners and losers. Once the consolidation has occurred in the business segment there will be a need to differentiate.

“Once this occurs there will be a drive for the entire supply channel to improve the efficiency and increase the energy output per dollar spent. We expect CSP to follow the traditional product maturity life cycle,” Thomsen said.

Low iron glass

The level of iron content in the glass varies depending on the efficiency and total cost of the solar application. Not all low iron glass is low iron solar glass; optimising for the visible spectrum does not return the necessary value to justify the increased price.

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IN-DEPTH: Glass maker cuts it