Solar Sandwich

by Jonathan McGaha | January 10, 2012 12:00 am

The Perth Amboy, N.J.-based Englert Inc.’s Solar Sandwich combines the beauty and durability of a standing seam metal roof system with the latest technological advances in solar heating and electrical generation to reduce a structure’s energy bill by 20 to 80 percent.

Englert’s SunNet thin film, solar laminates (BIPV) form the top layer of the sandwich, generating electricity from dawn to dusk. These laminates are made from lightweight and unbreakable self-adhesive materials and attach directly to the standing seam roof panel. They work well in cloudy, low light conditions and are excellent on curved roof surfaces. SunNet BIPV laminates are low profile and blend in nicely with most metal roof profiles. The standard laminate configuration includes a photovoltaic laminate with potted terminal housing assembly with output cables and quick-connect terminals such as Multi-Contact (MC) connectors with an adhesive backing.

Englert’s SunNet laminates come in three different rated power configurations-144, 136 and 68 Wp and feature bypass diodes for shadow tolerance, a key consideration for drawing energy in partially shaded areas. Production Pmax tolerance is ± 5 percent. The cell types are multi-junction amorphous silicon solar cells connected in series.

During the first eight to 10 weeks of operation, electrical output will exceed specified ratings and may be higher by 15 percent. Operating voltage may be higher by 11 percent and operating current higher by 4 percent. It should be noted that over time, actual performance may vary up to 10 percent from rated power due to low temperature operation and spectral effects.

An Englert standing seam roof metal roof is the critical platform and centerpiece of the Solar Sandwich. The roof supports the thin film laminates and a thermal energy system below it. The roof’s ULTRACool Kynar coatings meet Energy Star and LEED requirements for reflectivity and emissivity, reflecting heat away from the building, cutting urban smog and extending the life expectancy of the roof due to less expansion and contraction. Standing seam metal roofs will last at least twice as long as other roofing materials, providing an ideal, long-lasting platform for any solar energy system.

Installation temperature must be between 50 and 100 F. Maximum roof temperature for the system cannot exceed 185 F.

cannot exceed 185 F. The third layer is a solar thermal system installed under the standing seam roof that absorbs energy into a concealed collection system and transfers it to provide energy for the building’s heat and hot water. The system also automatically cools the roof making the Building Integrated Photovoltaics more efficient. The system uses heat generated by the sun shining directly on the standing seam metal roof. The solar energy collector employs glycol protected fluids to collect and transfer the solar energy to building systems using closed loop heat exchange technology. The system is supplied with a minimum 300-square-foot area configurable in a variety of shapes under the roof. Depending on weather and site variables, the 300-square-foot system can supply hot water preheating for a typical four-person household and have a rated capacity of a nominal 1500 to 2500 watts for solar thermal collection. solar_sandwich

Materials required to install the solar thermal system beneath the standing seam roof include thermal snaplock purlins that convey the heat from the roof, radiant-reflective insulation, flexible Pex tubing, thermistors to sense and measure temperatures and multiport manifold sets including actuators, balancing valves, flow rate indicators, pressure rest assembly and related accessories. The solar thermal component is terminated at the multiport manifold for connection to conventional circulation and storage systems.

The overall thickness of the Englert Solar Sandwich is 2.75 inches, including the laminates, standing seam roofing material and the solar thermal system. A roof can be selected in any of 26 LEED and Energy Star compliant colors. And Englert also offers a SunNet Blue coating that matches its SunNet PV laminate, making it almost impossible to distinguish the laminates from the standing seam material.

Jerry Heininger is coordinator of environmental products for Englert Inc., Perth Amboy, N.J. Heininger is a LEED Green Associate with the USGBC, an AP with the American Rainwater Catchment Systems Association, and a member and former president of the New Jersey Chapter of the Construction Specifications Institute. For more information, visit www.englertinc.com.

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