TY - JOUR

T1 - On the volume power density of radial thermoelectric generators

AU - Han, Minkyung

AU - Wee, Daehyun

N1 - Funding Information:
National Research Foundation of Korea, Grant/Award Number: NRF‐2019R1F1A1062571; Solvay SA Funding information
Publisher Copyright:
© 2020 John Wiley & Sons Ltd

PY - 2020/6/10

Y1 - 2020/6/10

N2 - We examine the volume power density of radial thermoelectric generators (TEGs). Radial, or tubular, TEGs have been considered as an alternative to the usual flat-plate TEGs due to its improved geometric match to typical curved heat sources and high surface power density. However, surface power density is not the only important performance index in realistic situations. Especially for TEGs with inorganic materials that have high raw material prices, volume power density can be important as well. In this note, an analytic model of a radial TEG is studied with a numerical trial-and-error approach for investigating its volume power density. At the same time, an alternative, approximate method of estimating the maximum power of the radial TEG is presented. Using these two approaches, we estimate the volume power density of a skutterudite-based radial TEG and compare the results to those of a flat-plate TEG. The volume power density of the radial TEG is significantly lower than that of the flat-plate TEG. For example, our calculation for a representative case with free convection on the cold side shows that the volume power density of the radial TEG will be 107 W/m3 at best. The result improves with forced convection, and our calculation for a representative case with forced convection on the cold side exhibits the maximum volume power density of 24 100 W/m3. All these values turn out to be smaller roughly by one order of magnitude than the maximum volume power densities of comparable flat-plate TEGs. Such a low volume power density indicates lower economic feasibility of the radial TEG with expensive inorganic thermoelectric materials. This is also explicitly discussed by presenting the high cost per watt of the radial TEG. It is therefore suggested that radial TEGs with less expensive organic materials may be more acceptable than those with inorganic ones.

AB - We examine the volume power density of radial thermoelectric generators (TEGs). Radial, or tubular, TEGs have been considered as an alternative to the usual flat-plate TEGs due to its improved geometric match to typical curved heat sources and high surface power density. However, surface power density is not the only important performance index in realistic situations. Especially for TEGs with inorganic materials that have high raw material prices, volume power density can be important as well. In this note, an analytic model of a radial TEG is studied with a numerical trial-and-error approach for investigating its volume power density. At the same time, an alternative, approximate method of estimating the maximum power of the radial TEG is presented. Using these two approaches, we estimate the volume power density of a skutterudite-based radial TEG and compare the results to those of a flat-plate TEG. The volume power density of the radial TEG is significantly lower than that of the flat-plate TEG. For example, our calculation for a representative case with free convection on the cold side shows that the volume power density of the radial TEG will be 107 W/m3 at best. The result improves with forced convection, and our calculation for a representative case with forced convection on the cold side exhibits the maximum volume power density of 24 100 W/m3. All these values turn out to be smaller roughly by one order of magnitude than the maximum volume power densities of comparable flat-plate TEGs. Such a low volume power density indicates lower economic feasibility of the radial TEG with expensive inorganic thermoelectric materials. This is also explicitly discussed by presenting the high cost per watt of the radial TEG. It is therefore suggested that radial TEGs with less expensive organic materials may be more acceptable than those with inorganic ones.

KW - heat transfer

KW - maximum power

KW - radial thermoelectric generators

KW - surface power density

KW - volume power density

UR - http://www.scopus.com/inward/record.url?scp=85081979643&partnerID=8YFLogxK

U2 - 10.1002/er.5317

DO - 10.1002/er.5317

M3 - Article

AN - SCOPUS:85081979643

SN - 0363-907X

VL - 44

SP - 6049

EP - 6057

JO - International Journal of Energy Research

JF - International Journal of Energy Research

IS - 7

ER -