ORIGINAL RESEARCH ARTICLE Improving the Economic Efficiency of Thermoelectric Generators by Optimizing Heat Transfer Conditions YURIY LOBUNETS 1,2,3 1.—The Gas Institute of the National Academy of Sciences of Ukraine, Kyiv, Ukraine. 2.—Solid Cell Inc., Rochester, NY, USA. 3.—e-mail: yurilobunets@yahoo.co.uk The use of low-potential energy sources is an urgent problem of our time, as more than 70% of the energy used by mankind is lost in the form of low-potential waste. A promising technology of converting such thermal energy into electricity is the thermoelectric method. The scale of use of any technology depends on its efficiency. The problem of TEG efficiency can be divided into two separate tasks—the task of creating efficient thermoelectric materials, and the task of optimizing the parameters of thermoelectric devices. In real conditions the last task plays a sig- nificant, often crucial, role. Therefore, many works are devoted to their research. The fundamental basis for solving this problem is the mathematical modeling of the thermoelectric generator circuit, which includes a heat source, a thermoelec- tric converter, a cooling system, and a payload. In this paper the author presents some generalized results of previous research that can benefit the developers of thermoelectric devices. The first part of the article presents the basics of the methodology used. Next, I draw attention to the possibility of better tuning of the properties of thermoelectric materials to a specific task in case of considering external conditions. The final part of the paper provides an assessment of technical and economic indicators of TEG and formulates the conditions under which this technology can ensure competitiveness in the modern energy market. Key words: Thermoelectric generator, TEG optimizations, TEG heat exchange system, system analyzing of TEG List of Symbols Bi Biot criterion I Electrical current (A) j Current density (A/cm 2 ) e Seebeck coefficient (V/K) E Electromotive force (V) k Coefficient of thermal conductivity (W/cm_K) r Coefficient of electrical conductivity (Xcm) 1 G o Specific cost ($/W) h Thermocouple leg length (cm, mm) J = jeh/k Dimensionless current density n The charge carrier concentration (cm 3 ) s Thermoelectric leg cross sectional area (cm 2 ) To Determining temperature (K) T h Hot junction temperature (K) T c Cold junction temperature (K) dT Junction temperature difference (K) t h Heat carrier temperature (K) t c Coolant temperature (K) dt Temperature difference of heat carriers (K) h = T/T o Dimensionless temperature #=t/T o Dimensionless temperature of fluid Ki=qh/kT o Dimensionless heat flow density z=e 2 r/k Thermoelectric figure-of-merit (K 1 ) zT o Dimensionless thermoelectric figure-of-merit N Electrical power (W) N o Specific power (W/cm 2 ) (Received June 11, 2020; accepted January 28, 2021; published online March 3, 2021) Journal of ELECTRONIC MATERIALS, Vol. 50, No. 5, 2021 https://doi.org/10.1007/s11664-021-08797-9 Ó 2021 The Minerals, Metals & Materials Society 2860