A Thermoelectric power generator is solid-state device that can converts heat directly into electricity. Such devices are based on thermoelectric effects involving interactions between the flow of heat and of electricity through solid bodies. A Thermoelectric Generator consists of a heat receiving plate, heat exiting plate and a Thermoelectric Generator Module. The heat receiving plate can be passively or activerly cooled with a fan or hydronic pump.
All thermoelectric power generators have the same basic configuration. A heat source provides the high temperature, and the heat flows through a thermoelectric converter to a heat sink, which is maintained at a temperature below that of the source. The temperature differential across the converter produces direct current (DC) to a load (RL) having a terminal voltage (V) and a terminal current (I). There is no intermediate energy conversion process. For this reason, thermoelectric power generation is classified as direct power conversion. The amount of electrical power generated is given by I2RL, or VLI.
With thermoelectric modules the direction of energy flow is reversible. For example,if the load resistor is removed and a DC power supply is substituted, the thermoelectric device can be used to move heat from the “heat source” element and lower its temperature. In this configuration, the reversed energy-conversion process of thermoelectric devices is invoked, using electrical power to pump heat and produce refrigeration. Any thermoelectric device can be applied in either mode of operation, though the design of a particular device is usually optimized for its specific purpose.
A systematic study began on thermoelectricity between about 1885 and 1910 by 1910 by a German scientist named Edmund Altenkirch. Altenkirch satisfactorily calculated the potential efficiency of thermoelectric generators. Unfortunately, the only materials available at the time were metallic conductors, leaving the thermoelectric generators with an efficiency of mo more than 0.5 percent. By 1940 a semiconductor-based generator with an efficiency of 4 percent had been developed. After 1950, thermoelectric power-generating efficiency gains were small, and efficiencies had reached not much more than 10 percent by the late 1980s. Units built in the early 21st Century have boasted exceeding 30% efficiency, however the highest efficiency available on the market today is 12 - 14 %. Regardless, low-power varieties of thermoelectric generators have proven to be of considerable practical importance. For example, those fueled by radioactive isotopes, which are generally used to power data transmissions from space or some of the new modern heating systems that are self-powered and have a net gain for pumping power back into the grid..
Thermoelectric power generators vary in size and shape, depending on the type of heat source/sink, the and the power requirement. During World War II, some thermoelectric generators were used to power portable communications transmitters. Improvements made in semiconductors between 1955 and 1965 expanded the practical range of applications. In practice, many units require a TEG power regulator to convert the generator output to a usable voltage. Tegpro manufactures a line of energy harvesting regulators known as Tegulators for produce regulated voltages & current.
Thermoelectric generators have been constructed to use natural gas, propane, butane, kerosene, jet fuels, and wood, as heat sources. Commercial units usually range from 10- to 100-watts of output power. They are used in remote area applications such as navigational aids, data collection and communications systems, and cathodic protection.
Solar thermoelectric generators have been designed to supply orbiting spacecraft power, though they have not been able to compete with efficient silicon solar cells. Thermoelectric devices can generate electrical power for use by other thermoelectric devices in dark areas of the spacecraft and to dissipate heat from the vehicle, utilizing solar heat from the Sun exposed side of the spaceshuttle.
In 2008 Tegpro started the develop of elements of a self-powered heat system. It was envisioned that heat systems could power their own control systems, circulating pumps fan etc. and have a net gain of power that could be fed into a battery bank such as a Tesla Power Wall or be grid tied. Tegpro has continued its work on Thermoelectric Generators and it now one of the Leading Engineering, Prototyping & Manufacturing companies in Thermoelectric Generator Technology.
Radioactive isotopes can be used to provide a high-temp heat source for thermoelectric generators. As the thermoelectric modules are resistant to nuclear radiation the generators provide a useful source of power for many unattended and remote applications. For example, radioisotope thermoelectric generators can provide electric power for deep-ocean data collection and various isolated communication systems. The power range of radioisotope thermoelectric generators can exceed over 100 watts. An example of this application is the Mars Curiosity Rover.
The core of any Thermoelectric Generator is the Thermoelectric Generator Module. The Thermoelectric Generator Module allows high temperature heat to pass through its heat receiving side and to exit from its heat exiting side. Some of the heat that passes through the module is converted to electric current. Tegpro manufactures a wide array of Thermoelectric Generator Modules that can be used at temperatures as high as 400 C.
Tegpro Thermoelectric Generator Modules available at Tegmart
More information about Thermoelectric Generators (Wikipedia)
Videos of Thermoelectric Generators (YouTube)
Thermoelectric Generator Forums (TEGPower.com)
More information Web Sites about Thermoelectric Generators below:
Basics of Thermoelectric Generators
Thermoelectric Generator Definitions
Basic information on the Thermoelectric Generator
More information on the Thermoelectric Generator
Electricity from Heat Educational Page
Stove Lite (World's First Wood Stove Powered Thermoelectric Lantern)
Devil Watt (Wood Burning Stove Thermoelectric Generators)
TEGPRO (Experts of TEG systems)
Tegulator (Complete line TEG power regulators Made in the USA)
Tegmart (Online Store: Wood Burning Stove Thermoelectric Generators, Energy Harverting Regualtors (Tegulator), and other Accessories)