Relationship between thermoelectric figure of merit and energy conversion efficiency
Relationship between thermoelectric figure of merit and energy conversion efficiency
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DOI：
10.1073/pnas.1510231112
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发表时间：
2015-07-07
影响因子：
11.1
通讯作者：
Ren, Zhifeng
中科院分区：
文献类型：
--
作者：
Kim, Hee Seok;Liu, Weishu;Ren, Zhifeng
热电器件热转化为电的最大效率（eta(max)）的无因次优值（ZT）公式已被广泛用于评价热电器件材料的可取性。不幸的是，根据平均ZT值的使用方式，eta（max）值变化很大，这引起了关于ZT在冷热侧温差较大的情况下的适用性的问题，因为忽略了影响ZT的材料特性的温度依赖性。为了避免复杂的数值模拟给出准确的效率，我们定义了一个工程无因次优值（ZT）（eng）和一个工程功率因数（PF）（eng）作为冷热侧温差的函数，分别可靠和准确地预测实际的转换效率和输出功率，克服了使用平均ZT值报告不切实际的效率的问题。
The formula for maximum efficiency (eta(max)) of heat conversion into electricity by a thermoelectric device in terms of the dimensionless figure of merit (ZT) has been widely used to assess the desirability of thermoelectric materials for devices. Unfortunately, the eta(max) values vary greatly depending on how the average ZT values are used, raising questions about the applicability of ZT in the case of a large temperature difference between the hot and cold sides due to the neglect of the temperature dependences of the material properties that affect ZT. To avoid the complex numerical simulation that gives accurate efficiency, we have defined an engineering dimensionless figure of merit (ZT)(eng) and an engineering power factor (PF)(eng) as functions of the temperature difference between the cold and hot sides to predict reliably and accurately the practical conversion efficiency and output power, respectively, overcoming the reporting of unrealistic efficiency using average ZT values.