Thermoelectric materials enable the direct conversion of thermal to electrical energy. One application of this is ambient heat energy harvesting where relatively stable temperature gradients existing between the inside and outside of a building could be utilized to produce electricity. Buildings can thus change from energy consumers to energy generators. This could ultimately help reduce the surface temperatures and energy consumption of buildings, especially in urban areas. In this paper, research work carried out on developing and characterizing a cement-based thermoelectric material is presented. Cement-based samples are doped with different metal oxides (Bi2O3 and Fe2O3) to enhance their thermoelectric properties, which are defined through their Seebeck coefficient, electrical conductivity and thermal conductivity. The study also discusses the positive impact of moisture content on the electrical conductivity
Hydrogen-rich syngas was generated
from Jatropha curcas (J. curcas)
shell biomass char in a Fresnel lens
solar concentrator assembly using solar thermal energy. The assembly
had two lenses arranged in such a manner that the focal point of both
coincided at a glass reactor, having a specially designed water inlet
mechanism. A dual axis automatic solar tracking system working in
a closed loop was utilized for continuously maintaining the focal
point on the reactor so that the desired high temperature could be
obtained for the reaction. The maximum temperature of 1087 °C
with a geometrical concentration of 215× was reached at the focal
plane. The theoretical efficiency of the system was found to be 67.44%.
The simulated results of the predicted temperature were first verified
experimentally without any reaction mixture, and they differed with
an average error of 7.85%. J. curcas shell char was
then steam gasified at the focus. A maximum char bed temperature of
736 °C could be achieved during the reaction, and 42.77% hydrogen
gas was obtained in the combustible gas mixture. In this work, a cost-effective
and modular assembly for high-temperature solar steam gasification
is designed and fabricated to make the process attractive and environmentally
benign.
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