Monday, February 27, 2012

DOE-funded battery breakthrough to halve cost, triple range | Grist

DOE-funded battery breakthrough to halve cost, triple range | Grist:

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A new breakthrough from California-based Envia Systems will yield lithium-ion batteries that are less than half the cost of current cells, while also having three times the energy density. And guess who funded it? The Department of Energy. That’s right: Sometimes, when the government invests in innovation, it pays off moon launch-big.

Envia’s announcement said that its packs would deliver cell energy of 400 watt-hours per kilogram at a cost of $150 per kilowatt-hour. Though it doesn’t disclose a cost breakdown, Tesla Motors rates the energy density of its Roadster’s pack at 121 watt-hours per kilogram. Envia said its energy-density performance was verified in testing of prototype cells at the Naval Service Warfare Center’s Crane evaluation division.

Envia’s breakthrough happens to match the price/performance point that some analysts consider the “holy grail” of battery characteristics required for mass commercialization. Which means that within a decade or so, cars like the Nissan Leaf and the Chevy Volt could be as popular as iPads.

Saturday, February 25, 2012

100-Mile Houses Expand the Locavore Movement From Food to Architecture - Design - GOOD

100-Mile Houses Expand the Locavore Movement From Food to Architecture - Design - GOOD:

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The rise of the locavore movement introduced millions of people to the 100-mile diet, which involves eating only food produced within one's own region. Now, a new focus on sustainable architecture is applying the same concept to homes.

The idea of a 100-mile house shouldn't be shocking: Historically, most homes were made using local materials simply because it was more practical. But in an age when even middle-class homeowners can order marble countertops from Italy and bamboo floors from China, creating a home entirely from local materials challenges builders to carefully consider every piece of the structure, from the foundation to the eaves.

Last week, the Architecture Foundation of British Columbia launched an international competition to design a 1,200-square-foot, four-person home that exclusively uses materials made or recycled within 100 miles of Vancouver. David M. Hewitt, the current chair of the Architecture Foundation, came up with the idea for the competition on a whim and presented it at a board meeting. "It was almost thrown out facetiously, and everybody latched onto it," he says.

Architects have consciously borrowed from the sustainable food movement in their efforts to make buildings greener—not coincidentally, Vancouver was also the birthplace of the 100-mile diet. In 2007, after they learned that the average ingredient travels 1,500 miles to a diner's plate, authors James MacKinnon and Alisa Smith chronicled their yearlong effort to eat only food sourced from within a 100-mile radius of their Vancouver home. Now, as the concept of sustainable building evolves, questions about where building materials are sourced and the environmental impacts of extracting, manufacturing, and transporting those materials are beginning to come into sharper focus.

Although a large percentage of the world's population live in homes made from local materials, the idea of intentionally setting geographic restraints on modern building materials is relatively novel. One example of an existing 100-mile house is the home built by naturalist and writer Briony Penn in British Columbia, just across the Strait of Georgia from Vancouver. With help from builder Michael Dragland, she applied the principles of the diet to the 1,150-square-foot home she recently built on Salt Spring Island.

"The 100-mile house is just fun," Penn says. "It provides a fun way to define how you're going to build a house, because you go out and you talk to all your neighbors, and it builds community and puts money back in the hands of everybody in your community."

Using local materials instead of those imported from distant lands lowers a building's embodied energy, which includes both the fuel required to extract raw materials from the earth and to transport them to the construction site. Limiting the distance materials must travel can also encourage a return to traditional building techniques, which typically have a lower environmental impact than the concrete, masonry and drywall used in modern homes.

Vancouver's geographic location—it is bordered by water to the west and mountains to the north and east—makes local sourcing of many materials quite a challenge. Penn milled all her own wood using a neighbor's saw and collected cedar driftwood from nearby beaches. She also incorporated a large number of salvaged materials into the home, including a slate roof from her grandfather's house (which had originally been salvaged from a different house), without ever stepping foot in Home Depot. Penn says she had to use plywood because of local building code, but she was able to find a Forest Stewardship Council-certified plywood company located within 100 miles.

The most difficult things to find within 100 miles were insulation and light fixtures, she says. For the insulation, she ended up using recycled rockwool, and she had some elements custom-made when she couldn't find items that fit her criteria.

Penn acknowledges that building a 100-mile house can be significantly pricier than a conventional home—hers cost about $300,000—but she says it was worth it. "If you just say, 'Here's my budget,' and then you build smaller, but sweeter, it's just a simple case of changing your parameters and values," she says. "Instead of trying to push for maximum space at the cheapest price, you push for maximum quality and you settle for less space, and honestly, you don't miss the space."

Hewitt emphasizes that 100-mile design can look sophisticated and modern, combatting stereotypes of self-built shacks in the woods. "We hope to get beyond the log cabin mentality," he says. "Hopefully, people will take the initiative and start questioning where we actually do get materials from. Why do we need to ship marble from Carrara, Italy all the way over here to put on our floors when we have so much rock in our back yard?"

Photo courtesy of Briony Penn


Submissions: Doodle What It Means to Be an Active Citizen

Jesus-Approved: The Rise of the Celebrity 'Purity Ring'

Tuesday, February 14, 2012

Seeeduino Stalker - Atmega 168

Seeeduino Stalker - Atmega 168:

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Engineers create tandem polymer solar cells that set record for energy-conversion

Engineers create tandem polymer solar cells that set record for energy-conversion:

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When compared to a single-layer device, the tandem device is more efficient in utilizing solar energy, particularly by minimizing other energy losses. By using more than one absorption material, each capturing a different part of the solar spectrum, the tandem cell is able to maintain the current and increase the output voltage. These factors enable the increase in efficiency, the researchers said.
"The solar spectra is very broad and covers the visible as well as the invisible, the infrared and the UV," said Shuji Doi, research group manager for Sumitomo Chemical. "We are very excited that Sumitomo's low-band gap polymer has contributed to the new record efficiency."
"We have been doing research in tandem solar cells for a much shorter length of time than in the single-junction devices," said Gang Li, a member of the research faculty at UCLA Engineering and a co-author of the Nature Photonics paper. "For us to achieve such success in improving the efficiency in this short time period truly demonstrates the great potential of tandem solar cell technology."
"Everything is done by a very low-cost wet-coating process," Yang said. "As this process is compatible with current manufacturing, I anticipate this technology will become commercially viable in the near future."
This study opens up a new direction for polymer chemists to pursue designs of new materials for tandem polymer solar cells. Furthermore, it indicates an important step towards the commercialization of polymer solar cells. Yang said his team hopes to reach 15 percent efficiency in the next few years.
Yang, who holds UCLA's Carol and Lawrence E. Tannas Jr. Endowed Chair in Engineering, is also faculty director of the Nano Renewable Energy Center at the California NanoSystems Institute at UCLA.
The study was supported by the National Science Foundation, the U.S Air Force Office of Scientific Research, the U.S. Office of Naval Research and the U.S. Department of Energy, together with the National Renewable Energy Laboratory.