Loyola Marymount University
and Loyola Law School
Mechanical Engineering Faculty Works
Nanofluid-Based Direct Absorption Solar
Loyola Marymount University, email@example.com
P. E. Phelan
R. S. Prasher
R. A. Taylor
Otanicar, Todd; Phelan, P. E.; Prasher, R. S.; Rosengarten, G.; and Taylor, R. A., "Nanofluid-Based Direct Absorption Solar Collector" (2010). Mechanical Engineering Faculty Works. Paper 21.
Otanicar, T.P., Phelan, P.E., Prasher, R.S., Rosengarten, G., and Taylor, R.A., 2010, "Nanofluid-Based Direct Absorption Solar Collector," Journal of Renewable and Sustainable Energy, 2(3).
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JOURNAL OF RENEWABLE AND SUSTAINABLE ENERGY 2, 033102 ͑2010͒
Nanoﬂuid-based direct absorption solar collector
Todd P. Otanicar,1,a͒ Patrick E. Phelan,2 Ravi S. Prasher,2 Gary Rosengarten,3 and Robert A. Taylor2
Department of Mechanical Engineering, Loyola Marymount University, Los Angeles, California 90045, USA
School of Mechanical, Aerospace, Chemical and Materials Engineering, Arizona State University, Tempe, Arizona 85287, USA
School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
͑Received 13 October 2009; accepted 23 April 2010; published online 26 May 2010͒
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 ͑nanoﬂuid͒ 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 silver͒. 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. © 2010 American Institute of Physics. ͓doi:10.1063/1.3429737͔
Sustainable energy generation is one of the most important challenges facing society today. Solar energy offers a solution, with the hourly solar ﬂux incident on the Earth’s surface being greater than all of the human consumption of energy in a year.1 The challenge lies in efﬁciently collecting and converting this energy into something useful. One of the principle methods of collection is through solar thermal collectors, which vary drastically in the amount of solar ﬂux captured2,3 as well as the method for capture.4 The most common type of solar thermal collector utilizes a black surface as the absorber, which then transfers heat to a ﬂuid running in tubes embedded within or fused onto the surface. In this case the efﬁciency is limited by not only how effective the absorber captures solar energy but also how effectively the heat is transferred to...
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