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Automotive Thermoelectric Generator
An automotive thermoelectric generator (ATEG) is a device that converts some of the waste heat of an internal combustion engine (IC) into electricity using the Seebeck Effect. A typical ATEG consists of four main elements: A hot-side heat exchanger, a cold-side heat exchanger, thermoelectric materials, and a compression assembly system. ATEGs can convert waste heat from an engine's coolant or exhaust into electricity. By reclaiming this otherwise lost energy, ATEGs decrease fuel consumed by the electric generator load on the engine. However, the cost of the unit and the extra fuel consumed due to its weight must be also considered. Operation principles In ATEGs, thermoelectric materials are packed between the hot-side and the cold-side heat exchangers. The thermoelectric materials are made up of p-type and n-type semiconductors, while the heat exchangers are metal plates with high thermal conductivity. The temperature difference between the two surfaces of the thermoelectric mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waste Heat
Waste heat is heat that is produced by a machine, or other process that uses energy, as a byproduct of doing work. All such processes give off some waste heat as a fundamental result of the laws of thermodynamics. Waste heat has lower utility (or in thermodynamics lexicon a lower exergy or higher entropy) than the original energy source. Sources of waste heat include all manner of human activities, natural systems, and all organisms, for example, incandescent light bulbs get hot, a refrigerator warms the room air, a building gets hot during peak hours, an internal combustion engine generates high-temperature exhaust gases, and electronic components get warm when in operation. Instead of being "wasted" by release into the ambient environment, sometimes waste heat (or cold) can be used by another process (such as using hot engine coolant to heat a vehicle), or a portion of heat that would otherwise be wasted can be reused in the same process if make-up heat is added to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Efficiency
In thermodynamics, the thermal efficiency (\eta_) is a dimensionless performance measure of a device that uses thermal energy, such as an internal combustion engine, steam turbine, steam engine, boiler, furnace, refrigerator, ACs etc. For a heat engine, thermal efficiency is the ratio of the net work output to the heat input; in the case of a heat pump, thermal efficiency (known as the ''coefficient of performance'') is the ratio of net heat output (for heating), or the net heat removed (for cooling) to the energy input (external work). The efficiency of a heat engine is fractional as the output is always less than the input while the COP of a heat pump is more than 1. These values are further restricted by the Carnot theorem. Overview In general, energy conversion efficiency is the ratio between the useful output of a device and the input, in energy terms. For thermal efficiency, the input, Q_, to the device is heat, or the heat-content of a fuel that is consumed. The des ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Neutrality
Carbon neutrality is a state of net-zero carbon dioxide emissions. This can be achieved by balancing emissions of carbon dioxide with its removal (often through carbon offsetting) or by eliminating emissions from society (the transition to the "post-carbon economy"). The term is used in the context of carbon dioxide-releasing processes associated with transportation, energy production, agriculture, and industry. Although the term "carbon neutral" is used, a carbon footprint also includes other greenhouse gases, measured in terms of their carbon dioxide equivalence. The term climate-neutral reflects the broader inclusiveness of other greenhouse gases in climate change, even if CO2 is the most abundant. The term "net zero" is increasingly used to describe a broader and more comprehensive commitment to decarbonization and climate action, moving beyond carbon neutrality by including more activities under the scope of indirect emissions, and often including a science-based target on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Back Pressure
Back pressure (or backpressure) is a resistance or force opposing the desired flow of fluid through pipes, leading to friction loss and pressure drop. The term ''back pressure'' is a misnomer, as pressure is a scalar quantity, so it has a magnitude but no direction. The fluid is what is directed, tending to flow away from high-pressure regions and toward low-pressure regions. If the low-pressure space is more high-pressure than intended (e.g. due to obstructions or tight bends in an exhaust pipe) or the high-pressure space is more low-pressure than intended, this opposes the desired flow and reduces the discharge. Similarly, bending or other operations on a pipe (such as a stock car exhaust system with a particularly high number of twists and bends) can reduce flow rate. Explanation A common example of backpressure is that caused by the exhaust system (consisting of the exhaust manifold, catalytic converter, muffler and connecting pipes) of an automotive four-stroke engine, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Motors
The General Motors Company (GM) is an American Multinational corporation, multinational Automotive industry, automotive manufacturing company headquartered in Detroit, Michigan, United States. It is the largest automaker in the United States and was the largest in the world for 77 years before losing the top spot to Toyota in 2008. General Motors operates manufacturing plants in eight countries. Its four core automobile brands are Chevrolet, Buick, GMC (automobile), GMC, and Cadillac. It also holds interests in Chinese brands Wuling Motors and Baojun as well as DMAX (engines), DMAX via joint ventures. Additionally, GM also owns the BrightDrop delivery vehicle manufacturer, GM Defense, a namesake Defense vehicles division which produces military vehicles for the United States government and military; the vehicle safety, security, and information services provider OnStar; the auto parts company ACDelco, a GM Financial, namesake financial lending service; and majority ownership in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alphabet Energy
Alphabet Energy was a startup company founded in 2009 at the University of California, Berkeley by thermoelectrics expert Matthew L. Scullin and Peidong Yang. The company uses nanotechnology and materials science applications to create thermoelectric generators that are more cost effective than previous bismuth telluride-based devices. The company is based in Hayward, California. It started with a license to use silicon nanowire developed at Lawrence Berkeley National Laboratory. They moved from UC Berkeley to offices in San Francisco in 2011, and later to Hayward. Alphabet has a number of patents related to the capture of waste heat for purposes of electricity generation. The company is working with tetrahedrite, a common mineral with thermoelectric properties. 2011's '' The Lean Startup: How Today's Entrepreneurs Use Continuous Innovation to Create Radically Successful Businesses'' describes Alphabet Energy's approach to product development as an example of the successful prac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Michigan State University
Michigan State University (Michigan State, MSU) is a public university, public Land-grant university, land-grant research university in East Lansing, Michigan. It was founded in 1855 as the Agricultural College of the State of Michigan, the first of its kind in the United States. It is considered a Public Ivy, or a public institution which offers an academic experience similar to that of an Ivy League university. After the introduction of the Morrill Land-Grant Acts, Morrill Act in 1862, the state designated the college a land-grant institution in 1863, making it the first of the land-grant colleges in the United States. The college became coeducational in 1870. In 1955, the state officially made the college a university, and the current name, Michigan State University, was adopted in 1964. Today, Michigan State has the largest undergraduate enrollment among Michigan's colleges and universities and approximately 634,300 living alums worldwide. The university is a member of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrahedrite
Tetrahedrite is a copper antimony sulfosalt mineral with formula: . It is the antimony endmember of the continuous solid solution series with arsenic-bearing tennantite. Pure endmembers of the series are seldom if ever seen in nature. Of the two, the antimony rich phase is more common. Other elements also substitute in the structure, most notably iron and zinc, along with less common silver, mercury and lead. Bismuth also substitutes for the antimony site and ''bismuthian tetrahedrite'' or ''annivite'' is a recognized variety. The related, silver dominant, mineral species freibergite, although rare, is notable in that it can contain up to 18% silver. Mineralogy Tetrahedrite gets its name from the distinctive tetrahedron shaped cubic crystals. The mineral usually occurs in massive form, it is a steel gray to black metallic mineral with Mohs hardness of 3.5 to 4 and specific gravity of 4.6 to 5.2. Tetrahedrite occurs in low to moderate temperature hydrothermal veins and in some co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead Telluride
Lead telluride is a compound of lead and tellurium (PbTe). It crystallizes in the NaCl crystal structure with Pb atoms occupying the cation and Te forming the anionic lattice. It is a narrow gap semiconductor with a band gap of 0.32 eV. It occurs naturally as the mineral altaite. Properties * Dielectric constant ~1000. * Electron Effective mass ~ 0.01 ''m''e * Hole mobility, μp = 600 cm2 V−1 s−1 (0 K); 4000 cm2 V−1 s−1 (300 K) Applications PbTe has proven to be a very important intermediate thermoelectric material. The performance of thermoelectric materials can be evaluated by the figure of merit, ZT=S^2\sigma T/\kappa, in which S is the Seebeck coefficient, \sigma is the electrical conductivity and \kappa is the thermal conductivity. In order to improve the thermoelectric performance of materials, the power factor (S^2\sigma) needs to be maximized and the thermal conductivity needs to be minimized. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bismuth Telluride
Bismuth telluride (Bi2Te3) is a gray powder that is a compound of bismuth and tellurium also known as bismuth(III) telluride. It is a semiconductor, which, when alloyed with antimony or selenium, is an efficient thermoelectric material for refrigeration or portable power generation. Bi2Te3 is a topological insulator, and thus exhibits thickness-dependent physical properties. Properties as a thermoelectric material Bismuth telluride is a narrow-gap layered semiconductor with a trigonal unit cell. The valence and conduction band structure can be described as a many-ellipsoidal model with 6 constant-energy ellipsoids that are centered on the reflection planes. Bi2Te3 cleaves easily along the trigonal axis due to Van der Waals bonding between neighboring tellurium atoms. Due to this, bismuth-telluride-based materials used for power generation or cooling applications must be polycrystalline. Furthermore, the Seebeck coefficient of bulk Bi2Te3 becomes compensated around room temperature, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skutterudite
Named after Skuterudåsen, a hill in Modum, Norway, skutterudite is a cobalt arsenide mineral containing variable amounts of nickel and iron substituting for cobalt with the ideal formula CoAs3. Some references give the arsenic a variable formula subscript of 2–3. High nickel varieties are referred to as nickel-skutterudite, previously chloanthite. It is a hydrothermal ore mineral found in moderate to high temperature veins with other Ni-Co minerals. Associated minerals are arsenopyrite, native silver, erythrite, annabergite, nickeline, cobaltite, silver sulfosalts, native bismuth, calcite, siderite, barite and quartz. It is mined as an ore of cobalt and nickel with a by-product of arsenic. The crystal structure of this mineral has been found to be exhibited by several compounds with important technological uses. The mineral has a bright metallic luster, and is tin white or light steel gray in color with a black streak. The specific gravity is 6.5 and the hardness is 5.5–6. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heusler Alloy
Heusler compounds are magnetic intermetallics with face-centered cubic crystal structure and a composition of XYZ (half-Heuslers) or X2YZ (full-Heuslers), where X and Y are transition metals and Z is in the p-block. The term derives from the name of German mining engineer and chemist Friedrich Heusler, who studied such a compound (Cu2MnAl) in 1903. Many of these compounds exhibit properties relevant to spintronics, such as magnetoresistance, variations of the Hall effect, ferro-, antiferro-, and ferrimagnetism, half- and semimetallicity, semiconductivity with spin filter ability, superconductivity, topological band structure and are actively studied as Thermoelectric materials. Their magnetism results from a double-exchange mechanism between neighboring magnetic ions. Manganese, which sits at the body centers of the cubic structure, was the magnetic ion in the first Heusler compound discovered. (See the Bethe–Slater curve for details of why this happens.) Styles of writing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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