Details
| Original language | English |
|---|---|
| Pages (from-to) | 69-78 |
| Number of pages | 10 |
| Journal | Energy Harvesting and Systems |
| Volume | 1 |
| Issue number | 1-2 |
| Early online date | 7 May 2014 |
| Publication status | Published - 1 Jun 2014 |
Abstract
The thermoelectric energy conversion is described in terms of fluxes of extensive variables entropy and charge, which gives a clear meaning to the figure of merit and to the power factor. Strength and sign of coupling of entropy current and electrical current is decisive for the function of a thermoelectric generator, which was built from n-type and p-type oxide ceramics to be suitable for the high-temperature range. For n-type and p-type legs, Zn0.98Al0.02O and Ca3Co4O9-derived ceramics, respectively, were used. Microstructure of both materials was investigated to some detail by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy including elemental analysis. N-type Zn0.98Al0.02O shows sub-micrometre precipitates of ZnAl2O4 spinel. P-type Ca3Co4O9-derived ceramic is a multi-phase composite as the starting powder decomposed partly during sintering. The thermoelectric materials show different temperature slopes of the power factor with the p-type material reaching 1.8 mW cm-1 K-2 at 1,000 K and the n-type reaching 1.6 mW cm-1 K-2 at 1,050 K. For the 10-leg thermoelectric generator, a figure of merit of zT = 0.10 was estimated at maximum electrical power output when the hot side was at 1,023 K, and a temperature difference of 200 K was applied.
Keywords
- entropy conductivity, figure of merit, high temperature, oxides, thermoelectric module
ASJC Scopus subject areas
- Energy(all)
- Renewable Energy, Sustainability and the Environment
- Energy(all)
- Energy Engineering and Power Technology
- Engineering(all)
- Electrical and Electronic Engineering
- Chemistry(all)
- Electrochemistry
Sustainable Development Goals
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In: Energy Harvesting and Systems, Vol. 1, No. 1-2, 01.06.2014, p. 69-78.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - A High-Temperature Thermoelectric Generator Based on Oxides
AU - Feldhoff, Armin
AU - Geppert, Benjamin
N1 - Publisher Copyright: © 2014 Walter de Gruyter GmbH. All rights reserved.
PY - 2014/6/1
Y1 - 2014/6/1
N2 - The thermoelectric energy conversion is described in terms of fluxes of extensive variables entropy and charge, which gives a clear meaning to the figure of merit and to the power factor. Strength and sign of coupling of entropy current and electrical current is decisive for the function of a thermoelectric generator, which was built from n-type and p-type oxide ceramics to be suitable for the high-temperature range. For n-type and p-type legs, Zn0.98Al0.02O and Ca3Co4O9-derived ceramics, respectively, were used. Microstructure of both materials was investigated to some detail by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy including elemental analysis. N-type Zn0.98Al0.02O shows sub-micrometre precipitates of ZnAl2O4 spinel. P-type Ca3Co4O9-derived ceramic is a multi-phase composite as the starting powder decomposed partly during sintering. The thermoelectric materials show different temperature slopes of the power factor with the p-type material reaching 1.8 mW cm-1 K-2 at 1,000 K and the n-type reaching 1.6 mW cm-1 K-2 at 1,050 K. For the 10-leg thermoelectric generator, a figure of merit of zT = 0.10 was estimated at maximum electrical power output when the hot side was at 1,023 K, and a temperature difference of 200 K was applied.
AB - The thermoelectric energy conversion is described in terms of fluxes of extensive variables entropy and charge, which gives a clear meaning to the figure of merit and to the power factor. Strength and sign of coupling of entropy current and electrical current is decisive for the function of a thermoelectric generator, which was built from n-type and p-type oxide ceramics to be suitable for the high-temperature range. For n-type and p-type legs, Zn0.98Al0.02O and Ca3Co4O9-derived ceramics, respectively, were used. Microstructure of both materials was investigated to some detail by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy including elemental analysis. N-type Zn0.98Al0.02O shows sub-micrometre precipitates of ZnAl2O4 spinel. P-type Ca3Co4O9-derived ceramic is a multi-phase composite as the starting powder decomposed partly during sintering. The thermoelectric materials show different temperature slopes of the power factor with the p-type material reaching 1.8 mW cm-1 K-2 at 1,000 K and the n-type reaching 1.6 mW cm-1 K-2 at 1,050 K. For the 10-leg thermoelectric generator, a figure of merit of zT = 0.10 was estimated at maximum electrical power output when the hot side was at 1,023 K, and a temperature difference of 200 K was applied.
KW - entropy conductivity
KW - figure of merit
KW - high temperature
KW - oxides
KW - thermoelectric module
UR - http://www.scopus.com/inward/record.url?scp=85126369239&partnerID=8YFLogxK
U2 - 10.1515/ehs-2014-0003
DO - 10.1515/ehs-2014-0003
M3 - Article
AN - SCOPUS:85126369239
VL - 1
SP - 69
EP - 78
JO - Energy Harvesting and Systems
JF - Energy Harvesting and Systems
SN - 2329-8774
IS - 1-2
ER -