Nanofluid-based direct absorption solar collector

Journal of Renewable and Sustainable Energy - Tập 2 Số 3 - 2010
Todd Otanicar1, Patrick E. Phelan2, Ravi Prasher2, Gary Rosengarten3, Robert A. Taylor2
1Loyola Marymount University 1 Department of Mechanical Engineering, , Los Angeles, California 90045, USA
2Arizona State University 2 School of Mechanical, Aerospace, Chemical and Materials Engineering, , Tempe, Arizona 85287, USA
3University of New South Wales 3 School of Mechanical and Manufacturing Engineering, , Sydney, New South Wales 2052, Australia

Tóm tắt

Solar energy is one of the best sources of renewable energy with minimal environmental impact. Direct absorption solar collectors have been proposed for a variety of applications such as water heating; however the efficiency of these collectors is limited by the absorption properties of the working fluid, which is very poor for typical fluids used in solar collectors. It has been shown that mixing nanoparticles in a liquid (nanofluid) has a dramatic effect on the liquid thermophysical properties such as thermal conductivity. Nanoparticles also offer the potential of improving the radiative properties of liquids, leading to an increase in the efficiency of direct absorption solar collectors. Here we report on the experimental results on solar collectors based on nanofluids made from a variety of nanoparticles (carbon nanotubes, graphite, and silver). We demonstrate efficiency improvements of up to 5% in solar thermal collectors by utilizing nanofluids as the absorption mechanism. In addition the experimental data were compared with a numerical model of a solar collector with direct absorption nanofluids. The experimental and numerical results demonstrate an initial rapid increase in efficiency with volume fraction, followed by a leveling off in efficiency as volume fraction continues to increase.

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Journal of Renewable and Sustainable Energy

Tập 2 Số 3

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