Characterization of a nanofluid volumetric solar absorber / steam generator

Robert A. Taylor, Patrick Phelan, Ronald Adrian, Andrey Gunawan, Todd Otanicar

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Scopus citations

Abstract

Solar thermal energy has shown remarkable growth in recent years - incorporating many new technologies into new applications [1]. Nanofluids - suspensions of nanoparticles in conventional fluids - have shown promise to make efficient volumetric-absorption solar collectors [2-4]. It has also been shown that concentrated light energy can efficiently cause localized phase change in a nanofluid [5]. These findings indicate that it may be advantageous to create a 'direct, volumetric nanofluid steam generator'. That is, a solar collector design which could minimize the number of energy transfer steps, and thus minimize losses in converting sunlight (via thermal energy) to electricity. To study this, we use a testing apparatus where concentrated laser light at 532 nm - a wavelength very near the solar spectrum peak - is incident on a highly absorbing sample. The highly absorbing samples compared in this study are black dyes, black painted surfaces, and silver nanofluids - with de-ionized water as a base fluid. Each of these samples converts light energy to heat - to varying degrees - in a localized region. This region is monitored simultaneously with a digital camera and an infrared camera. The resulting observed temperature profile and bubble dynamics are compared for these fluids. For pure water with a black backing, some very high temperatures (>300°C) are observed with a laser input of ∼75 W/cm2. Using a similar absorption potential, we observed higher temperatures in the nanofluids when compared to black dyes. A simplified boiling heat transfer analysis based on these results is also presented. We also noticed differences in bubble size and growth rates for the different samples. Overall, this study represents a proof-of-concept test for a novel volumetric, direct steam generator. These results of this test indicate that it may be possible to efficiently generate steam directly in a controlled, localized volume - i.e. without heating up passive system components.

Original languageEnglish (US)
Title of host publicationASME 2011 5th International Conference on Energy Sustainability, ES 2011
Pages1927-1936
Number of pages10
EditionPARTS A, B, AND C
DOIs
StatePublished - Dec 1 2011
EventASME 2011 5th International Conference on Energy Sustainability, ES 2011 - Washington, DC, United States
Duration: Aug 7 2011Aug 10 2011

Publication series

NameASME 2011 5th International Conference on Energy Sustainability, ES 2011
NumberPARTS A, B, AND C

Other

OtherASME 2011 5th International Conference on Energy Sustainability, ES 2011
CountryUnited States
CityWashington, DC
Period8/7/118/10/11

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Renewable Energy, Sustainability and the Environment

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  • Cite this

    Taylor, R. A., Phelan, P., Adrian, R., Gunawan, A., & Otanicar, T. (2011). Characterization of a nanofluid volumetric solar absorber / steam generator. In ASME 2011 5th International Conference on Energy Sustainability, ES 2011 (PARTS A, B, AND C ed., pp. 1927-1936). (ASME 2011 5th International Conference on Energy Sustainability, ES 2011; No. PARTS A, B, AND C). https://doi.org/10.1115/ES2011-54062