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ad telluride (Tl-PbTe), has a zT of 1.5. The new material is most effective between 450° and 950°F—a typical temperature range for power systems such as automobile engines. The application of TE material to automotive waste heat recovery systems is of interest to the research team, and to one of the project funders, BSST Corporation. ( Earlier post .) The dimensionless zT for thermoelectric materials is calculated by the formula zT= T*(S2σ)/κ), where S is the thermoelectric power or Seebeck coefficient of the TE material, σ and κ are the electrical and thermal conductivities, respectively, and T is the absolute temperature. Recent progress in increasing the efficiency of thermoelectric materials has primarily involved decreasing κ by using nanomaterials to lower the thermal conductivity by scattering phonons. Quantum-dot superlattices have reported values of zT >2, and silicon nanowires have such a reduced κ that zT approaches that of commercial materials. Although this certainly provides the evidence that high-zT material can be prepared, the results were obtained on thin films or nanowires that are challenging for high-volume applications that normally rely on bulk materials. Structural complexity on various length scales has successfully reduced κ in bulk TE materials, also yielding zT >1. Unfortunately, in bulk material at least, there is a lower limit to the lattice thermal conductivity imposed by wave mechanics: The phonon mean free path cannot become shorter than the interatomic distance. The minimum thermal conductivity of PbTe is about 0.35 W/mK at 300 K, a value measured on quantum-dot superlattices. Although lower values have been seen for interfacial heat transfer, progress beyond this point in bulk materials must come from the numerator [of the equation] and in particular the Seebeck coefficient; we describe here a successful approach in this direction for bulk materials. —Heremans 2008 For the new material, the researchers left out the nanostructures, and instead focused on how to convert the maximum amount of heat that was trapped in the material naturally. A 2006 paper (S. Ahmad et al.) published in the journal Physical Review Letters suggested that elements such as thallium and tellurium could interact on a quantum-mechanical level to create a resonance between the thallium electrons and those in the host lead telluride thermoelectric material, depending on the bonds between the atoms. It comes down to a peculiar behavior of an electron in a thallium atom when it has tellurium neighbors. We’d been working for 10 years to engineer this kind of behavior using different kinds of nanostructured materials, but with limited success. Then I saw this paper, and I knew we could do the same thing we’d been trying to do with nanostructures, but with this bulk semiconductor instead. —Joseph Heremans Heremans designed the new material with Vladimir Jovovic, who did this work for his doctoral thesis in the Department of Mechanical Engineering at Ohio State. Researchers at Osaka University—Ken Kurosaki, Anek Charoenphakdee, and Shinsuke Yamanaka—created samples of the material for testing. Then researchers at the California Institute of Technology—G. Jeffrey Snyder, Eric S. Toberer, and Ali Saramat—tested the material at high temperatures. Heremans and Jovovic tested it at low temperatures and provided experimental proof that the physical mechanism they postulated was indeed at work. The team found that near 450° F, the material converted heat to electricity with a zT of about 0.75&madsh;close to that of sodium doped telluride—but as the temperature rose, so did the efficiency of the new material. It peaked at 950° F with a zT of 1.5. Heremans’ team is continuing to work on this patent-pending technology, and is targeting boosting zT by another factor of two. We anticipate that deliberately engineered impurity-induced band-structure distortions will be a generally applicable route to enhanced S and zT in all TE materials. We are optimistic about the commercial use of such PbTe-based materials because there is an extensive knowledge base among the manufacturers of thermoelectric generators about the assembly of PbTe-based devices, in particular the ability to make stable metallic contacts with low thermal and electrical resistance. —Heremans 2008 The research was funded by the BSST Corporation; the State of Ohio Department of Development’s Center for Photovoltaic Innovation and Commercialization at Ohio State University; the Beckman Institute; the Swedish Bengt Lundqvist Minne Foundation; and NASA’s Jet Propulsion Laboratory. Go to Source If you liked this article, Digg it! or click here to subscribe to my RSS feed and receive periodic alternative energy news. Posted in Green News on Jul 25, 2008 Comments RSS Leave a Reply Name (required) Mail (will not be published) (required) Website Notify me of followup comments via e-mail ← Vauxhall’s Ellesmere Port plant could get Volt production in Europe Peugeot Citroën Japan To Release Lower-Priced Entry-Level Car →

Tags: automotive, trends, heat, exchanger on 2008-07-25 -All Annotations (0) -About

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The statements from EPRI and the car company also address safe and convenient vehicle charging, public education and other public policies, including codes and standards.

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The company’s charging stations use a simple key fob, like the one you might already use to buy gas, to unlock the station.

Tags: Battery, charging, station, technology, automotive, transport on 2008-07-23 -All Annotations (0) -About

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If you watch The Green Optimistic you already know that we covered air cars in previous posts, both MDI CAT’s and the Angelo DiPietro air motor. The first time we wrote about these inventions was about 6 months ago. Now, MDI and Angelo DiPietro have contracts all over the world with auto makers to sell them the compressed air technology

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Toyota is planning to add solar-powered air conditioning to high-end models of its Prius hybrid cars, a report says.

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MOSCOW, June 27 (RIA Novosti) - Gazprom is proposing opening a chain of filling stations using natural gas as an alternative car fuel across Europe, the chief of the Russian energy giant said on Friday.

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In less than 7 years, Mercedes-Benz plans to ditch petroleum-powered vehicles from its lineup. Focusing on electric, fuel cell, and biofuels, the company is revving up research in alternative fuel sources and efficiency.

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It seems to me that the auto industry has a very intriguing opportunity right now to use all of the recent entrepreneurial and investment activity in clean transportation tech to their benefit. This opportunity could help them address the evident “gap” between highly innovative demonstration vehicle programs, and the historically slow pace of adoption of core innovations into mass-production models.

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Google’s conference this week on plug-in electric vehicles and related federal policy clearly positions the search company’s RechargeIT program as an EV incubator for startups, R&D initiatives and policy discussions. Dan Reicher, Google.org’s director of climate change and energy initiatives, opened the conference, which was heavily attended by beltway insiders, by announcing that Google would invest in multiple ventures to make wide-scale plug-in electric cars viable.

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Toyota has just announced that as from 2009 shall make available to the public two new hybrid models, in addition to the new version of the Prius.

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Oh, it can be done. There are no scientific laws that say you can't run a car on water. In fact, a Japanese company is the latest to claim they have pulled it off. See the video here: Water-fuel car unveiled in Japan However, what you can't do is run a car on water without energy inputs greater than you get from splitting the water.

Tags: automotive, water, energy on 2008-06-16 and saved by3 people -All Annotations (0) -About

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6) Electro-thermal recapture – converting the thermal energy wasted from the exhaust back into electric power. It’s not available yet but, according to Origo Industries’ Ian Houston and Oaktec’s Paul Andrews, both believe the exhaust is the greatest waste of energy in the car and that this will be the next big leap for the hybrid car industry.

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Friday, the U.S. Environmental Protection Agency (EPA) amended an obscure clean water regulation that restricted use of aluminum in automobiles because of a potentially harmful byproduct created in the manufacturing process. Car makers treat aluminum to increase protection from corrosion in multiple ways, but the cheapest is an adhesive bonding process that uses zinc phosphate.

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The soaring price of oil seems to be forcing a sea change in the car business.

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The future of Tata's forthcoming Nano - the cheapest car in the world - could be jeopardised by rising steel prices.

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He also considers other surprising effects of going car-less, like feeling a greater connection to and awareness of his community and immediate surroundings, being in public (versus within the protective, private confines of the car), that cars travel so very, very fast (!), the joy of a car-free vacation, and how living without a car can lead you to be more contemplative.

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