Architecture

Disassembling Concrete with Lightning

Philip Proefrock

Researchers from the Fraunhofer Institute for Building Physics have developed a method to break down old concrete debris into its constituents for better recycling and re-use of the material. The process, called electrodynamic fragmentation, uses very short pulses (less than 500 nanoseconds) of induced lightning to separate gravel from cement materials in concrete.

Concrete is a material with a mixed environmental pedigree. Although its workability and durability make it extremely useful for a lot of purposes, it also has several drawbacks. There are the environmental impacts from the production of concrete, and it is also a major component of the materials going into landfills, so this makes the idea of recycling concrete a compelling one.

At present, most concrete recycling is merely to crush it and use it for sub-base under roads. This is better than landfilling it, but is a downcycling of the material. With the new lightning process, the aggregates can be more readily salvaged and re-used in new concrete.

Production of new cement from the recovered, separated material would be the ultimate goal of concrete recycling, since the production of cement is one of the single most intensive sources of CO2 emissions at present. While this process does not accomplish that, it does lay the way for that kind of recycling to become a possibility.

image: CC BY-SA 2.0 by brewbooks

via: Gizmag

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Google Supporting USGBC on Green Building Materials

Philip Proefrock

A grant of $3 million from Google to the US Green Building Council (USGBC) was announced during the annual Greenbuild conference which is taking place in San Francisco this week. Google has been a leader with the greening of its own facilities and has taken a very proactive step in avoiding the use of "red list" construction materials in its own facilities.

The grant is meant to be used for furthering green building materials research and the promotion of communications in and around the green building process. "The grant supports three related efforts: research on building materials and their effect on health, development of new building transparency tools, and encouraging conversation between industry stakeholders." More specific detail about how this grant will be applied by USGBC remains to be announced.

Google's grant gives the USGBC some leverage of its own since some credits in the LEED building rating system have been targets of objection by strong monied interests. These include the credit for use of certified sustainable wood and the proposed materials credits that incorporate open reporting of chemical content of products and "for selecting products for which the chemical ingredients in the product are inventoried using an accepted methodology and for selecting products verified to minimize the use and generation of harmful substances."

via: Eco-Structure

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All-Natural Insulation with Expanded Cork Boards

Philip Proefrock

Cork is a very versatile material with a great green pedigree. It is considered a rapidly renewable material because the bark of the cork oak can be harvested without killing the tree, allowing repeated cycles of production over the 200+ year lifespan of the tree. While cork has long been an attractive choice for flooring, it is now being used to provide building insulation boards, as well.

Like cork flooring, the cork insulation is also made from granules of cork that are left over after wine corks have been punched out of the bark. Cork granules are treated under heat and pressure to release a natural binder and produce billets of expanded cork which are then cut to size. The expanded cork has an R-value of 3.6 per inch. This isn't as good as the highest performance materials, but is comparable to fiberglass batts, cotton (blue jean insulation), and cellulose insulation.

Expanded cork insulation at present is a comparatively expensive material for insulation. The cost comparison from Building Green (who have an extensive write-up of the material) indicates that cork might be as much as 5 times the cost of a similar amount of polyisocyanurate insulation board, and more than twice as expensive as extruded polystyrene. But the cork does not rely on petrochemicals for its manufacture, and offers an all-natural insulation product that will definitely appeal to some builders and building owners.

In addition to its energy performance, the cork insulation is also highly flame resistant, helps with sound absorbtion, and does not offgas any significant VOCs. From a LEED perspective, it is a very useful material, qualifying as a rapidly renewable material in addition to being manufactured from the waste byproduct of the manufacture of another product (wine corks). Many cork forests are already FSC certified. And, from the perspective of a materials red list, it is 100% natural.

via: Jetson Green

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Hotels Not Getting Greener (Even the Green Ones)

Philip Proefrock

A recent article in Metropolis magazine notes that, in spite of the trends toward greener construction in both the construction and hospitality industries, recently built hotels tend to be worse, in terms of energy consumption, than those built in the 1960s, and asks, "Is hotel design inherently unsustainable?"

The information, and the accompanying graphic, makes a comparison based on energy used and CO2 emissions equivalents per room per night. The average hotel room built in the 1960s represents the equivalent of 12.2 kilograms (26.9 pounds) CO2, while rooms built between 1997 - 2007 represent an equivalent of 21.5 kilograms (47.4 pounds) of CO2 emissions.

One important point that may be responsible for some of the difference may be the same trend in housing that is pushing for larger and larger footprints. Larger rooms and increased numbers of amenities increase energy demand, and often far more than the offsetting efficiency measures.

Although we continue to get press releases about new, green hotels being built, these few examples, even when they do incorporate extremely strong energy efficiency measures, are all too rare. A few good examples aren't enough to stem an apparent overall tide that seems headed in the wrong direction.

image: Metropolis and Wikimedia Commons

via: Metropolis Magazine

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Super, Super Efficient Windows

Philip Proefrock

In conventional construction, the windows of a building are usually the weakest part of the thermal envelope. Well insulated walls can be built with a number of different kinds of construction and a variety of insulation materials. But windows, particularly ones that the inhabitants of the building can see through, are hard to make as efficient as the walls they are installed in. But prototype windows from Super Windows have astonishing thermal resistance as well as good visibility.

These windows are ridiculously efficient. As noted on Jetson Green, "The inventive window makes it possible to achieve European U-values of 0.15 W/m2K, or the U.S. equivalent of R38 (R = 1/(.15/5.678))." For comparison, the insulation value of batt insulation in a 2 x 4 stud wall has a U.S. R-value of just R-11. That makes the windows more than 3 times as effective an insulator than the walls are.

These windows are only developmental at this point. Even if they were in commercial production and affordable, they would not be easily retrofit into many homes because these windows are about 160mm (more than 6 inches) thick. The windows are made with two panes of glass and ten (!) intervening film layers that provide this astonishing level of performance.

For high performance buildings such as highly insulated and extremely low energy consuming Passive House designs, these windows may be especially desirable. Even more moderated versions of these windows could provide more efficient windows by adapting lessons from these prototype designs.

image: Super Windows

via: Jetson Green

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