Thomas Seebeck observed in 1821 that, when heat is transferred between two objects, an electromagnetic field is created. Since then, that electromagnetic field has been harnessed and converted into electricity with the advent of thermoelectric generators. Thermoelectric generators have a wide range of applications in fields ranging from household appliances to spacecraft technology. Though thermoelectricity has the potential to greatly impact energy waste, limitations remain in terms of cost and efficiency.
Thermoelectric generators are particularly useful because they turn a waste product, in the form of heat, into a usable resource in the form of electricity. Thermoelectric generators are solid-state devices that provide a method for converting the necessary waste product of heat into a reusable energy resource. An enormous number of machines create waste heat, from your household refrigerator to industrial power plants. Heat energy is responsible for almost 90 percent of global electricity production, but the limitations of existing system efficiency results in more than half of that heat energy being wasted as "waste heat." Thermoelectric generators have to potential to reduce the amount of waste heat and, in turn, provide a renewable source of electricity generation.
Most types of machine engines experience drops in efficiency when they are scaled down in size; thermoelectric generators do not experience the same scalability challenges. The scalability of thermoelectric generators means that they can be applied to a broader scope of applications than other types of engines. Thermoelectric generators maintain their efficiency in applications as small as home use, such as a water heater, and in applications as large as power plants and other industrial applications.
Efficiency and Cost
In 2006, the United States Department of Energy reported that most of the commercially available thermoelectric generators operate at just 3 percent efficiency, a level that translated into approximately $30 per watt. In order for thermoelectric generators to be competitive in the current market, the cost per watt would need to be closer to $5, and the efficiency would need to increase to at least 15 percent to 20 percent. Since the report, the technology has been advancing toward this goal. For example, in 2012, engineers at Michigan State and Northwestern University released a report on a new material that would increase thermoelectric generators efficiency to between 15 percent and 20 percent. In 2014, an article published in "Advanced Energy Materials" described a process in which thermoelectric films were manipulated to double their energy efficiency to nearly 30 percent. Though these increased efficiency strategies are promising for thermoelectric power generation, they remained in development and were not largely commercially available as of 2014.
Thermoelectric generators serve a range of applications. Curiosity, the Mars rover, uses thermoelectric generators for power, and many automobile manufacturers are using or experimenting with the technology for use in cars. However, the largest energy impact that thermoelectric generators could deliver is in larger scale implementations in power plants and factories, where continuous running of combustion engines expend tremendous amounts of waste heat. The generators have yet to be widely applied to these broader potentials, though advancements in efficiency are incentivizing their adoption in manufacturing industries.
- Advanced Energy Materials: Enhanced Thermoelectric Power Factor of NaxCoO2 Thin Films by Structural Engineering
- Digi-Key: Thermoelectric Energy Generation Takes Flight for Aircraft and Spacecraft Monitoring
- Cornell University Library: Thermoelectric Devices: Cooling and Power Generation
- Enclyclopedia Britannica: Thermoelectric Power Generator
- Stanford University: Thermoelectric Generators
- Power Practical: How Thermoelectric Generators Work
- Royal Society of Chemistry: Thermoelectric Cost Analysis
- U.S. Department of Energy: Engineering Scoping Study of Thermoelectric Generator Systems for Industrial Waste Heat Recovery
- Thermoelectric Gencell Technology: Thermoelectric Power
- Giz Mag: World's Most Efficient Thermoelectric Material Developed
- Photo Credit davidionut/iStock/Getty Images
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