(位移传感器专业英语)thermoelectric effect

Device efficiency
The efficiency of a thermoelectric device for electricity generation is given by η, defined as
The maximum efficiency ηmax is defined as
Figure of merit
The figure of merit Z for thermoelectric devices is defined as
where σ is the electrical conductivity, κ is the thermal conductivity, and S is the Seebeck coefficient. The dimensionless figure of merit ZT is formed by multiplying Z with the average temperature.
Applications
Peltier effect
The Peltier effectபைடு நூலகம்can be used to create a refrigerator which is compact and has no circulating fluid or moving parts; such refrigerators are useful in applications where their advantages out weigh the disadvantage of their very low efficiency.
Applications
Seebeck effect
The Seebeck effect is used in the thermoelectric generator, which functions like a heat engine, but is less bulky, has no moving parts, and is typically more expensive and less efficient. These have a use in power plants for converting waste heat into additional power (a form of energy recycling), and in automobiles as automotive thermoelectric generators (ATGs) for increasing fuel efficiency. Space probes often use radioisotope thermoelectric generators with the same mechanism but using radioisotopes to generate the required heat difference.
Thermoelectric effect
Team Members : Yanlong Mao
Jiahao Huo
Qindong Sun
Yongbin Yang Xiaomin Liu Fei Wu Yulin Zhao
Abstract
The thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice-versa . A thermoelectric device creates a voltage when there is a different temperature on each side. Conversely , when a voltage is applied to it, it creates a temperature difference. At the atomic scale, an applied temperature gradient causes charge carriers in the material to diffuse from the hot side to the cold side, similar to a classical gas that expands when heated; hence inducing a thermal current.
Applications
Temperature measurement Thermocouples and thermopiles are devices that use the Seebeck effect to measure the temperature difference between two objects, one connected to a voltmeter and the other to the probe. The temperature of the voltmeter, and hence that of the material being measured by the probe, can be measured separately using cold junction compensation techniques.
Contents
1. Seebeck effect 2. Peltier effect 3. Thomson effect 4. Figure of merit 5. Device efficiency 6. Applications
Thomson effect
The Thomson effect was predicted and subsequently observed by Lord Kelvin in 1851. It describes the heating or cooling of a current-carrying conductor with a temperature gradient. Any current-carrying conductor (except for a superconductor) with a temperature difference between two points either absorbs or emits heat, depending on the material. If a current density J is passed through a homogeneous conductor, the heat production q per unit volume is:
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