Company Developing Thermo-Electric Materials for Waste-Heat Energy Recovery

NASA’s Jet Propulsion Laboratory, Pasadena, California, has licensed patents on high-temperature thermoelectric materials to Evident Technologies, Troy, New York, which provides these kinds of materials and related power systems.

Source: phys.org

>” […] Thermoelectric materials convert heat into electricity. For example, by using this technology, waste-heat from a car could potentially be fed back into the vehicle and used to generate electricity. This would increase efficiency and deliver low-cost solutions for harvesting waste heat.

“The licensed technology could be applied to convert heat into electricity in a number of waste heat recovery applications, including automobile exhaust and high-temperature industrial processes such as ceramic and glass processing plants,” said Thierry Caillat, task leader for the thermoelectrics team at JPL.

JPL has a long history of high-temperature thermoelectric development driven by the need for space mission power in the absence of sunlight. Many space probes that leave Earth’s orbit use thermoelectrics as their electrical power source.  […]”<

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Aluminum Superatoms – High Temperature Superconducting Materials

Superconductors can carry electricity with no resistance and are used for specialized applications like MRIs, maglev trains and particle accelerators. Superconductor-based electronics would be extremely efficient because they would generate no waste heat, but he fact that they would only work at temperatures close to absolute zero makes them impractical.

Source: www.gizmag.com

>” […]

Scientists at the University of Southern California (USC) have made steps toward discovering a new family of superconductor materials that work at relatively high temperatures, with possible applications in physics research, medical imaging and high-performance electronics.

As electrons travel through an integrated circuit, they regularly bump into microscopic imperfections within the conductive wire and veer off course, creating electrical resistance and releasing waste energy as heat. Waste heat is a big inconvenience to both designers and end-users of electronics, but it simply can’t be avoided using the materials currently at our disposal.

[…] Thirty years ago, a new class of so-called “high-temperature superconductors” was discovered, although the name can be deceiving because these still require temperatures below 135 K (-135 °C or -210 °F) to operate, which still makes them impractical for use in electronics.

Now the USC team led by professor Vitaly Kresin has discovered hints of yet another family of superconductors which work at relatively high temperatures. Specifically, they found out that while single atoms of aluminum only turn superconductive at very low temperatures (around 1 K), so-called “superatoms” (clusters of evenly spaced atoms that behave as a single atom) of aluminum turn superconductive at much higher temperatures, around 100 K.

Superconductivity takes place when so-called Cooper pairs form within a material. These are pairs of electrons that are very faintly attracted to each other and activate a mechanism whereby the electrons don’t veer off course, and therefore lose heat, whenever they bump into an imperfection within the material. Because the attractive force between the electrons, which happens only under certain conditions, is so weak (two electrons would normally repel each other), even a small amount of external energy (which could be given off in the form of heat) can upset this equilibrium. This is why superconductors only work at very low temperatures.

Kresin and team built a series of aluminum superatoms between 32 and 95 atoms large. For superatoms containing 37, 44, 66 and 68 aluminum atoms, the scientists found evidence that Cooper pairings were taking place, turning the material into a superconductor.

The researchers suggest that creating superatoms of different metals could lead to the discovery of similar superconductors that work at relatively high temperatures. While the threshold temperature was 100 K (-280 °F, -173 °C) for an aluminum superatom, different materials are likely to turn superconductive at different (hopefully much higher) temperatures.

“One-hundred Kelvin might not be the upper-temperature barrier,” says Kresin. “It might just be the beginning.”

Should one of these materials operate as a superconductor at room temperature, it would likely have huge impact on the worlds of electronics, medical imaging, microscopy and electric motors, just to name a few. ”

A paper describing the advance appears on the journal Nano Letters.

Source: University of Southern California

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Thermoelectric Solid-State Cooling Technology Wins $44.5M Funding

The near-term applications for Phononic’s science are high-end refrigeration for labs and medical facilities, as well as cooling for fiber optics and data servers that are “necessary to continue Moore’s law,” according to the company.

Source: www.greentechmedia.com

>” […] The 75-employee Phononic develops thermoelectrics — materials that can convert a temperature gradient to a voltage or vice versa. The technology is a brilliant pursuit, but no one has brought it to mass markets economically or at scale just yet. Traditional thermoelectrics use materials such as bismuth telluride or silicon germanium, and more recently, silicon nanowires.

[…] Phononic is looking to develop thermal management technology for consumer devices, and, more strikingly, to replace cheap, ubiquitous and century-old incumbent compressor technology.

CEO Anthony Atti told us this morning that the investment thesis around Phononic is that “semiconductors have revolutionized IT and LEDs, but have not had that same impact on cooling and heating.” He notes that Phononic’s thermoelectric technology is in the realm of Peltier cooling technology, but addresses three major shortcomings of that technology: efficiency, ability to scale, and ease of integration. […]

Atti claims that the compound semiconductor material used in his firm’s thermoelectrics can be manufactured using high-volume, standard semiconductor tools and equipment.

Bruce Sohn, the former president of First Solar, is on the board at Phononic. When we spoke with him this morning, he told us that he had been working with the firm for four years and believes the startup is doing something “revolutionary that can do to compressors what the [integrated circuit] did to the vacuum tube.”

Other companies developing thermoelectric technologies for cooling or capturing waste heat include the following:

  • Alphabet Energy is commercializing thermoelectric waste-heat harvesting technology developed at Lawrence Berkeley National Laboratory and has raised more than $30 million from Encana, a developer of natural gas and other energy sources,
  • TPG Biotech, Claremont Creek Ventures, and the CalCEF Clean Energy Angel Fund.GMZ Energy, spun out of MIT with funding from KPCB, BP Alternative Energy, and Mitsui Ventures, is working on a bismuth-telluride thermovoltaic device that converts solar heat directly into power via the Seebeck effect. In the Seebeck effect, a sharp temperature gradient can result in an electric charge.
  • MTPV describes its product as a thermophotovoltaic. MTPV uses a silicon-based MEMS emitter which takes heat and transfers radiation to a germanium-based photovoltaic device, according to an article inSemiconductor Manufacturing and Design. The company just raised $11.2 million led by Northwater Capital Management’s Intellectual Property Fund, along with Total Energy Ventures, SABIC, the Saudi Basic Industries Corporation, and follow-on investments from Spinnaker Capital, Ensys Capital, the Clean Energy Venture Group and other existing shareholders.
  • Silicium, funded by Khosla Ventures, is investigating high ZT thermoelectrics. The firm’s website claims, “Silicium is developing silicon thermoelectrics that enable substantially increased battery longevity for wearable electronics. By using body heat, Silicium technology can help power an entire spectrum of wearable devices…using off-the-shelf silicon wafers.
  • “Recycled Energy Development (RED) and Ormat have retrofitted factories to capture waste heat, not using thermoelectrics, but by adding CHP or cogeneration. […]”<

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Scientists Discover New Form of Crystalline Order with High Potential for Thermoelectrics

 

InterlacedCrystalsSince the 1850s scientists have known that crystalline materials are organized into 14 different basic lattice structures. However, a team of researchers from Vanderbilt University and Oak Ridge National Laboratory (ORNL) now reports that it has discovered an entirely new form of crystalline order that simultaneously exhibits both crystal and polycrystalline properties, which they describe as “interlaced crystals.”

Source: www.energyharvestingjournal.com

>” […] The interlaced crystal arrangement has properties that make it ideal for thermoelectric applications that turn heat into electricity, they report. The discovery of materials with improved thermoelectric efficiency could increase the efficiency of electrical power generation, improve automobile mileage and reduce the cost of air conditioning.   “We discovered this new form while studying nano particles,” said Sokrates Pantelides, University Distinguished Professor of Physics and Engineering at Vanderbilt, who coordinated the study. “It most likely exists in thin films or bulk samples, but it has apparently gone unnoticed.”  […]

According to the researchers, the interlaced crystal structure may be just what is needed to optimize thermoelectric applications for power generation or cooling. Thermoelectric devices need a material that is an excellent electrical conductor and a poor conductor of heat. The problem is that materials like metals that are good electrical conductors also tend to be good heat conductors and vice versa. Defects and grain boundaries that retard heat flow also reduce electrical conductivity.   In addition to CuInS2, there is a large class of materials that should have similar interlaced structures. When made into thin films, they should be excellent thermoelectric materials, the researchers predict.   “We haven’t tested this yet, but we are confident that these materials have high electrical conductivity and low thermal conductivity…just what you need for thermoelectrics. The field is now wide open for scientists who can fabricate thin films and make thermoelectric measurements,” said Pantelides.”<

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