Solar Energy Cells Meet PVC—A Brilliant Match

When you laminate photovoltaic cells to highly reflective PVC roofing membrane, you get an ecological one-two punch: Solar energy is harnessed to generate electricity, and unwanted heat is reflected away from buildings. This patented solar integrated roof system is topping buildings in California and in Europe.

For a start, Stan Graveline, vice president of Sarnafil, Inc. (Canton, Mass.), explained that his company’s EnergySmart Roof®, a reflective white PVC roofing membrane, deflects heat from buildings, thus lowering cooling costs. It also reduces the expanse of dark surfaces that absorb heat and cause “urban heat islands.” Temperatures on these heat islands can be five to ten degrees higher than in the surrounding rural areas. The higher the temperature, Graveline said, the greater the smog formation.

Building on these passive advantages, Solar Integrated of Los Angeles laminates flexible photovoltaic cells to EnergySmart Roof® membranes to produce a 10 ft.-by-20 ft. integrated solar roofing panel. This lightweight photovoltaic system is more efficient than the traditional glass panels, Graveline explained. With glass panels, he said, you have to cut through the roof to bring the wiring into the building. And wherever the roof is penetrated, there is a potential for leaking. With the building integrated photovoltaic (BIPV) solar electric roofing system, wiring is underneath the membrane, so there’s no penetration. Also, unlike existing technologies, these unique photovoltaic cells can generate power even when the weather is overcast.

Sarnafil’s PVC membrane filled the bill for Solar Integrated, which needed a roofing membrane that was reflective, would last at least 20 years, was low-maintenance, and—given that the wires below the membrane would be conducting electricity—had the greatest fire resistance.
 
This new technology is not cheap. But thanks to federal subsidies and state and local rebates (particularly in California), Solar Integrated’s BIPV system is becoming more affordable for commercial operations. Joel Davidson, Solar Integrated’s vice president for quality and process improvement, explained that, given the 30 percent federal tax credit for solar improvements that took effect this year (up from the 10 percent in place since 1990), plus state rebate programs, plus the energy the roof system generates, a business can turn its new roof into an asset, rather than one long 39.5-year depreciation expense.

For more information, visit www.sarnafilus.com and  www.solarintegrated.com.