文章基本信息

标题：Relationship between thermoelectric figure of merit and energy conversion efficiency
本地全文：下载
作者：Hee Seok Kim ; Weishu Liu ; Gang Chen 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2015
卷号：112
期号：27
页码：8205-8210
DOI：10.1073/pnas.1510231112
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceThermoelectric materials generate electricity from temperature gradients. The dimensionless figure of merit, ZT = S2{rho}-1{kappa}-1T, is calculated from the Seebeck coefficient (S), electrical resistivity ({rho}), and thermal conductivity ({kappa}). The calculated efficiency based on ZT using the conventional formula is not reliable in some cases due to the assumption of temperature-independent S,{rho} , and{kappa} . We established a new efficiency formula by introducing an engineering figure of merit (ZT)eng and an engineering power factor (PF)eng to predict reliably and accurately the efficiency of materials at a large temperature difference between the hot and cold sides, unlike the conventional ZT and PF providing performance only at specific temperatures. These new formulas will profoundly impact the search for new thermoelectric materials. 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.
关键词：thermoelectrics ; engineering figure of merit ; engineering power factor ; conversion efficiency ; cumulative temperature dependence