– PY

More than 13 million tons (13.2 million tonnes) of glass are generated annually in the U.S., which keeps its price—currently about $150 per ton ($148 per tonne), according to Dombrowski—more than competitive with stone chips. And the result is a very attractive product, particularly to what Wausau perceives as the growing market for green building products. While there are other terrazzo-like products that use recycled glass, such as IceStone from Great Harbor Design Center and Vetrazzo from Counter/Production, such materials generally require either a background matrix or a coating of epoxy to sequester the recycled glass from reacting with cement. “With epoxy at about $21 per gallon ($5.50/liter) and epoxy-coated recycled glass at about $2,500 a ton ($2,460/tonne),” says Dombrowski, “we can make tile and other terrazzo products with recycled glass a lot more economically.” Wausau Tile is one of the largest terrazzo product manufacturers in the world, with a state-of-the-art 300,000 ft2 (27,900 m2) facility. The new recycled-glass-content terrazzo tile is approximately 60% recycled glass by weight.

To the best of our knowledge, this product is no longer available.

Just when we thought emergency exit sign illumination had reached an unbeatable low-energy plateau with LED (light-emitting diode) technology, we learn of a quite different technology offering even greater energy savings and some performance advantages. LightPanel™ exit signs from LightPanel Technologies, LLC are

electroluminescent exit signs that consume less than a half a watt of electricity using a patented light-emitting capacitor (LEC) technology.

According to the most recent EPA estimates, there are about 60 million gas-powered lawn mowers in operation in the U.S.—40 million push mowers and 20 million riding tractors. These small spark-ignition engines generate 2.5% of total national summertime hydrocarbon and nitrous oxide pollution. Is there a reasonable alternative?

The new reel mowers will surprise you—they are light (as little as 17 pounds, or 7.7 kg!), quiet, fume-free, and cut rather than tear your grass. For those of us who are old enough to have experienced the more primitive versions of the reel mower, it is hard to overcome those sweaty, blade-jamming nightmares. Today’s reel mowers, however, are precision equipment that require no more—and perhaps less—effort to operate than a standard gas-powered push mower. And since reel mowers are now designed to self-sharpen, they are virtually maintenance-free.

You do have to be diligent about grass length—the level of effort goes up quite a bit if the grass length exceeds 4–6” (100–150 mm) and the thin wiry seed stalks are allowed to mature (they tend to bend easily and spring back up after the reel passes). The Scott reel mower, for one, does a fine job—a

Pentstar Corporation of Minneapolis, Minnesota has developed a new building system based on their patented Concrete Form Masonry Unit (CFMU). Think of the system as a hybrid of masonry block and cast-in-place concrete construction. Recycled-content plastic webs connect inner and outer finished masonry faces and an inner layer of 2” (50 mm) rigid foam (see diagram). The blocks are set in mortar, as are traditional concrete masonry units, and the 5” (125 mm) grout cavity is filled with concrete. The result is a completed wall system with both exterior and interior finished surfaces.

Inventor and company owner John Spakousky is a veteran masonry contractor growing increasingly concerned with the lack of innovation and performance in masonry construction, particularly in cold climates. “I wanted a block system that was easy to install, energy-efficient, environmentally friendly, and versatile—so I developed the system myself,” says Spakousky.

Transparent insulation was developed to increase the thermal performance of glazings without significantly reducing the light transmission. One pioneer in transparent insulation, Dr. K. G. T. Hollands of the University of Waterloo in Ontario, was initially looking for ways of improving performance of solar water heating collectors. By creating a honeycomb matrix of transparent film between two layers of glazing, small air pockets are created that effectively block convective currents. One of Hollands’ doctoral students, Douglas Milburn, went on to found a company to commercialize this concept: Advanced Glazings, Ltd. After pursuing markets in the passive solar and commercial greenhouse industries, the company shifted its focus to commercial daylighting and in late 2000 introduced Solera®.

Solera is referred to as a translucent glazing unit (TGU). Two layers of glass are separated by 2.5 inches (64 mm), and the interglazing space is filled with honeycomb transparent insulation made from clear acrylic film. Because of the geometry of the transparent insulation—optimally sized honeycomb channels are formed that are perpendicular to the glazing plane—both convective and radiative heat loss through the glazing are significantly reduced. Less than 5% of heat flow through Solera glazing is due to convection, according to Milburn, while convective heat flow through conventional glazing—in which there is an unbroken air space the area of the glazing unit—is far greater. The honeycomb structure effectively suppresses heat flow no matter what the pitch of the glazing—from horizontal to vertical, says Milburn.

The listed U-factor for Solera is 0.25 to 0.20 (1.2 to 1.4 W/m2·°C). Neither low-e coatings nor low-conductivity gas fill (such as argon or krypton) are required to achieve this exceptional energy performance. Because air is used in the Solera TGU, risk of lowered energy performance if the gas leaks out is not a worry. A capillary tube in the Solera TGU is part of the “equilibrium moisture dynamics” system used to prevent moisture condensation and equalize pressure inside the TGU. This approach also eliminates risk of breakage or seal failure if the product is shipped over high-elevation passes—a problem with sealed insulated-glass units (see

There are quite a few insulated concrete form (ICF) systems on the market whose manufacturers make a variety of resource efficiency claims.

EBN came across an interesting newcomer, Tech Block, at this year’s Greenprints conference in Atlanta. Tech Block uses 100% recycled EPS in a cementitious matrix similar to the popular Rastra system (see EBN Vol. 5, No. 4).

EBN

Vol. 4, No. 3). That product was based on the British product Stramit, which was invented in the 1940s and has been in production for more than 50 years in England. Unfortunately, less than a year after Stramit USA began production, the company folded for a variety of reasons (see

In large part, we have Danny Parker and his father-in-law to thank. Parker, a senior researcher at the Florida Solar Energy Center, tells the story:

“One hot Florida summer evening, my father-in-law, Shep Shepperd, and I were sitting around talking over a drink. I remarked how much cooler it felt under the ceiling fan above us. A retired airline pilot, having flown many a propeller-driven aircraft, Shep looked up and said—‘Yep, but those damn things haven’t changed since I’ve been around.’ Shep is 83. I asked him what he meant by that. ‘Well,’ he said, ‘I never flew an airplane with a flat propeller.’ That started me thinking about why ceiling fan blades are flat in the first place....”So started Parker’s investigation of ceiling fans. His research identified four areas with real potential for increasing energy efficiency and performance:

For the first time, builders and architects can specify gypsum wallboard with a certified recycled content of 99%. Temple-Inland—with distribution to most areas of the Southeast, Southwest, and Midwest—earned Scientific Certification System’s green cross and globe emblem for wallboard products being manufactured in West Memphis, Arkansas and Cumberland City, Tennessee. Temple-Inland achieved this certification because these plants obtain 100% of their gypsum supply from flue-gas desulfurization processes at Tennessee Valley Authority coal-fired electric power plants (see

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