The panels are comprised of 9-inch cells with bypass diode construction. (Photo credit: Uni-solar)

The 2009 American Institute of Architects (AIA) trade show was held May 1-2 at the Mosconi Convention Center in San Francisco. As always, it was a fascinating display of new products for the construction industry--from space age lighting and new framing systems to faucets and appliances that resemble art.

I revisited one technology that is really getting some attention called Integrated Photovoltaics. Integrated means architects finally have access to solar panel systems that blend in so well with the design they disappear into it. I have never been enamored with banks of solar panels on a roof, and my architect friends always cringed whenever a winery decided to "gild" the design with "glass boxes."

The system being promoted is thin-film solar collection technology. As the name implies, thin-film is a super thin, lightweight, polymer-coated laminate, which is simply glued onto a 16-inch-wide, standing-seam metal roofing panel. A leading O.E.M. manufacturer of thin-film is Uni-Solar in Michigan, and it is being distributed through metal roofing manufacturers like Fabral and Sheffield.

It was immediately apparent to me that thin-film solar has distinct advantages over traditional crystalline-silicon installations. Thin-film collectors, available in 9- and 15-foot sections, are extremely durable (can actually be walked on), flexible and conform to whatever roof shape the architect has designed. They can be applied at the factory or in the field from a roll.

Flexible thin-film solar panels are ready for installation on standing-seam roofing. (Photo credit: Actus Lend Lease)

Rugged polymer panels conform to any shape roof. (Photo credit: Kalzip)

Unlike heavier and fragile crystalline photocells, there is no need for a costly external support structure. This means there is less material and, therefore, less roof-structure engineering and no roof penetrations to promote leaks.

They are quick and easy to apply, can withstand hurricane force winds, do not trap debris, require no maintenance and blend in with the roof.

Efficiency

Thin-film panels have a much wider range of solar collection time due to their low (morning) effective angle-of-incidence (vertical tilt) at 10 degrees rather than the traditional 25 degrees. As the saying goes: "They wake up earlier and then go to sleep later."

The second factor in collection efficiency is the azimuth angle or the angle of divergence from direct north or south. Most solar systems prefer due south, but thin-film efficiency means solar collection is possible at a wider angle further away from that axis. Resultantly, they are more forgiving of a winery's roof orientation.

The UV-stabilized laminate utilizes "triple-junction" silicon layers, which absorb a much wider spectrum of light colors from the sun. The result is better performance in low light, cloudy and hot temperature conditions.

Another good idea is the double or bypass diode construction; the panels are made up of 9-inch cells; and if one should fail, it will not affect the overall system.

Installation

What is really cool is that the roofing companies I visited will coordinate complete design through installation. For the architect this would include CAD drawings and a complete equipment schedule; for the electrical subcontractor, all schematics and specifications will be provided.

The solar packages are sold complete, meaning the vendor (Fabral) will arrange for combiner boxes, inverters (to change solar DC to AC), transformers, phase converters, all the way to the utility interface. Obviously 110/220 volt inverters and three-phase converters are available.

Good advice is to design the winery's collection system like everything else: accommodate the existing facility and plan for future growth. The key is to up-size the inverter (at installation) to handle additional panels.

Sizing the System

Sizing a system is critical for any solar installation. If it is after-market with an older building on a utility, the customer collects one year of utility bills to determine average Kw usage. New winery construction will require a projected usage audit. Keep in mind most winery process equipment utilizes 220-volt, three-phase equipment from Europe.

System purchases are usually based on a cost-per-watt basis while the ROI is based on other factors such as the total kWh produced, amount and size of incentives and tax credits. The roofing company must have that information broken down state by state.

With the current interest in solar and government rebate programs, most installations will demonstrate a return on investment of 10 years or less. With the inherent savings in thin-film technology, five is now considered the norm.

Wineries should also factor in the potential savings of metal roofing through Energy Star, a joint program of the EPA and U.S. Department of Energy. In theory, metal roofs with certain colors will reflect solar energy, stay cooler and therefore require less energy for internal temperature control. Tax and energy credits are available just because of the roof material.

In addition to these savings, the winery may meet the requirements of LEED Energy and Atmosphere Credit 2 (renewal energy) and the LEED 2.2 Solar Reflective Index.

Finally, there is absolutely no maintenance after thin-film installation other than to monitor the system components. Warrantees are for 25 years with an 80 percent guarantee of original output at that time. Life expectancy is estimated to be 45 years depending on location.

What's Cool: What's not to like about this product? Thin-film photovoltaics is the future because of cost, ease of installation, efficiency and overall system simplicity. Architects and winery owners will appreciate the visual relief from standard solar collectors.

It gets even better. With the BIPV installation of thin-film panels, wineries will produce energy. With a metal roof, they will save energy. And with metal roofing being the perfect rainwater collector, the winery performs the ultimate hat-trick. Save, generate and harvest (see Rainwater Harvesting in the July 2009 issue of WBM).

For more information, contact www.energypeak.com or 888-216-9600.

Send new product information to Bill Pregler at bpregler@winebusiness.com