Beyond zT: Is There a Limit to Thermoelectric Figure of Merit?
Beyond zT: Is There a Limit to Thermoelectric Figure of Merit?
复制标题
超越 zT：热电品质因数是否有限制？
DOI：
10.1007/s11664-019-06943-y
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发表时间：
2019
影响因子：
2.1
通讯作者：
Lobunets, Yuriy
中科院分区：
文献类型：
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作者：
Lobunets, Yuriy
无因次热电优值T的概念是由A.F. Ioffe和已被广泛用于评估器件的热电材料的可取性。固体物理学并没有对这个标准设定限制，但可以证明，这种限制是由热力学定律强加的。zT的物理意义可以解释为热电发电机（TEG）的有效效率η o与卡诺效率ηc的比值：zT=ηo/ηc。因此，关于zT限制的结论：lim（zT）≤ 1，这与充分研究的热电材料的性质的数据相关，但与许多新的实验数据相矛盾。这种矛盾作为进一步研究zT可能的约束的借口。该分析的额外好处是通过直接测量温度、热通量和开环电压来实验确定zT的可能性。对TEG扩展数学模型的分析表明，毕奥判据对TEG功率容量的影响明显超过zT。也就是说，由于更强烈的热传递，可以补偿材料的高热导率。这种方法来改善的特性证明，通过开发一个TEG的潜热的液化天然气（LNG）的转换。
The concept of the dimensionless thermoelectric figure of meritzTwas derived by A.F. Ioffe and has been widely used to assess the desirability of thermoelectric materials for devices. Solid state physics does not set limits on this criterion, but it can be shown that such restrictions are imposed by the laws of thermodynamics. The physical meaning ofzTcan be interpreted as the ratio of the virtual efficiency of a thermoelectric generator (TEG)ηoand the Carnot efficiencyηc:zT=ηo/ηc. Hence, the conclusion about thezTrestriction: lim(zT) ≤ 1, which is correlated with the data on the properties of well-studied thermoelectric materials, but contradicts much new experimental data. This contradiction serves as a pretext for further study of possible constraints onzT. An additional bonus from this analysis is the possibility of the experimental determination of zTby direct measurement of temperatures, heat flux, and open circle voltage. An analysis of the expanded mathematical model of a TEG shows that the influence of the Biot criterion on the power capacity of the TEG significantly exceeds the influence ofzT. That is, it is possible to compensate for the high thermal conductivity of materials due to more intense heat transfer. This approach to improving the characteristics is demonstrated by developing a TEG for the conversion of latent heat of liquid natural gas (LNG).