Materials Sciences and Applications, 2012, *, ** doi:****/msa.2012.***** Published Online ** 2012 (http://www.scirp.org/journal/msa)
Thermoelectric Generator of Ceramic Materials Apisak Gavpisarn, Suwit Jugsujinda, Tosawat Seetawan* Thermoelectrics Research Center, Faculty of Science and Technology, Sakhon Nakon Rajabhat University, 680 Nittayo Road, Mueang District, Sakhon Nakon, Thailand 47000 *
[email protected] Receiv***
ABSTRACT This research has objective to development and fabrication thermoelectric generator (TEG) from polycrystalline of p-type is Ca3Co4O9 and n-type is CaMnO3 ceramic materials. The TEG was used the p-type and n-type of 71 couples which cut and polished to dimension of 4 × 4 × 4 mm3. The relationship of differential temperature and electrical voltage, electrical current, electrical power and conversion efficiency were measured. The results showed that the electricity and efficiency were increased with increasing differential temperature. The maximum voltage, current, power and efficiency were obtained of about 1.6 V, 300 mA, 105 mW and 5×10-5%, respectively at differential temperature of 60 K. Keywords: thermoelectric generator; p-Ca3Co4O9 and n-CaMnO3 ceramic materials;
1. Introduction In view of global energy and environmental problems, research and development have been promoted in the field of thermoelectric power generation as a means of recovering vast amounts of waste heat emitted by automobiles, factories, and similar sources. Waste heat from such the sources offers a high-quality energy source equal to about 70 % of total primary energy, but is difficult to reclaim due to its source amounts being small and widely dispersed. Thermoelectric generation systems offer the only viable method of overcoming these problems by converting heat energy directly into electrical energy irrespective of source size and without the use of moving parts or production of environmentally deleterious wastes. The requirements placed on materials needed for this task, however, are not easily satisfied. Not only must they possess high conversion efficiency, but must also be composed of non-toxic and abundantly available elements having high chemical stability in air even at temperatures of 800-1000 K. Thermoelectric modules are composed of in the metallic compounds, such as Bi2Te3, Pb-Te, and Si-Ge. Practical applications of materials like these have been delayed by problems such as their low melting or decomposition temperatures, their content of harmful or scarce elements, and their cost. Recently, oxide compounds have attracted attention as promising thermoelectric materials because of their potential to overcome the above mentioned problems [1-7].
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Fig. 1. Diagram of thermoelectric generator
2. Methodology Preparation of cell thermoelectric type p is calcium cobalt oxide and n is the calcium manganese oxide were cut and polished to look into the matter, 4×4×4 mm3 in size as well as the 71 pieces as shown in Fig. 2. The circuit breaker for a cell with an area of 6×6×0.5 mm3 distance between cells 1 mm lead sheet alumina wonder that the electrode with copper. TEG was prepared by placing the cells on the plate at the bottom alumina and copper electrodes above and then tests the full range of the terminals with a multi meter. Connect the red positive power of p-type cells and black lines show the n-type
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electrode from the cell, as shown in Fig. 2.3, then the alumina layer on the copper plate on the top electrode. The electrical of TE module was measured the electrical voltage, current and power as shown in Fig. 4.
3. Results and Discussion The TE module has been generated maximum electrical voltage about 1.6 V at differential temperature of 60 K as shown in Fig. 5. The electrical current was obtained maximum value of 300 mA as show in Fig. 6. The electrical power maximum about 105 mW is showed in Fig. 7. The relationship between differential temperature and conversion efficiency was increased with increasing differential temperature and obtained the maximum value of 5.0×10-5 %.
Fig. 2. Fabrication of thermoelectric module
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Fig.3. Thermoelectric module
Fig. 5. The relationship between of differential temperature and electrical voltage
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Fig. 4. Electricity measurement of thermoelectric module
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Fig. 6. The relationship between of differential temperature and electrical current
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the battery cells to copper. The results showed that the voltage and current to calculate power by increasing the temperature difference. The temperature difference of about 60 K with the voltage and current to calculate power at 1.6 V, 300 mA and 105 mW, respectively
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5. Acknowledgement
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This work was financially supported by the Electrical Generating Authority of Thailand (EGAT).
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REFERENCES
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Fig. 7. The relationship between of differential temperature and electrical power 6.0x10
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Fig. 8. The relationship between of differential temperature and conversion efficiency
4. Conclusion Thermoelectric generators dielectric type p is calcium cobalt oxide and the n is the calcium manganese oxide per electrode p-n using cell p and n-type of 71 couples. The cut and polished stones make Chemicals and CaMnO3, Ca3Co4O9 a size 4×4×4 mm3 cubes and place it on a piece of alumina material made with copper electrodes. Adhesive silver using a connector between
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[1] I. Terasaki, Y. Sasago and K. Uchinokura, “Large thermoelectric power in NaCo2O4 single crystals”, Physical Review B, Vol. 56 (1997), pp. 12685-12687. [2] R. Funahashi, I. Matsubara, H. Ikuta, T. Takeuchi, U. Mizutani, and S. Sodeoka, “An oxide single crystal with high thermoelectric performance in air”, Japanese Journal of Applied Physics, Vol. 39 (2000), pp. L1127-1129. [3] Y. Miyazaki, K. Kudo, M. Akoshima, Y. Ono, Y. Koike, T. Kajitani., “Low-temperature thermoelectric properties of the composite crystal [Ca2Co 3.34 ] 0.614[CoO2]”, Japanese Journal of Applied Physics, Vol. 39 (2000), p. L531. [4] R. Funahashi and I. Matsubara,. “Thermoelectric properties of Pb and Ca-doped (Bi2Sr2O2)xCoO2 whiskers”, Applied Physics Letters, Vol. 79 (2001), pp. 362-364 [5] M. Ohtaki, H. Koga, T. Tokunaga, K. Eguchi, H.Arai., “Electrical transport properties and high-temperature thermoelectric performance of (Ca 0.9M 0.1)MnO (M = Y, La, Ce, Sm, In, Sn, Sb, Pb, Bi)”, Journal of Solid State Chemistry, Vol. 120 (1995), p. 105-111. [6] Y. Masuda, M. Ohta, W. Seo, W. Pitschke, and K. Koumoto., Structure and thermoelectric transport properties of isoelectronically substituted (ZnO) InO”, Journal of Solid State Chemistry, Vol. 150 (2000), pp. 221-227 [7] W. Shin, and N. Murayama., “Li-doped Nickel oxide as a thermoelectric material”, Japanese Journal of Applied Physics, Vol. 38 (1999), pp. L1336-1338. .
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