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Title: Nanoparticle enhanced ionic liquid heat transfer fluids

Abstract

A heat transfer fluid created from nanoparticles that are dispersed into an ionic liquid is provided. Small volumes of nanoparticles are created from e.g., metals or metal oxides and/or alloys of such materials are dispersed into ionic liquids to create a heat transfer fluid. The nanoparticles can be dispersed directly into the ionic liquid during nanoparticle formation or the nanoparticles can be formed and then, in a subsequent step, dispersed into the ionic liquid using e.g., agitation.

Inventors:
; ; ; ;
Publication Date:
Research Org.:
Savannah River Technology Center (SRTC), Aiken, SC (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1150095
Patent Number(s):
8,801,957
Application Number:
13/234,284
Assignee:
Savannah River Nuclear Solutions, LLC (Aiken, SC) SRO
DOE Contract Number:
AC09-08SR22470
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY

Citation Formats

Fox, Elise B., Visser, Ann E., Bridges, Nicholas J., Gray, Joshua R., and Garcia-Diaz, Brenda L. Nanoparticle enhanced ionic liquid heat transfer fluids. United States: N. p., 2014. Web.
Fox, Elise B., Visser, Ann E., Bridges, Nicholas J., Gray, Joshua R., & Garcia-Diaz, Brenda L. Nanoparticle enhanced ionic liquid heat transfer fluids. United States.
Fox, Elise B., Visser, Ann E., Bridges, Nicholas J., Gray, Joshua R., and Garcia-Diaz, Brenda L. Tue . "Nanoparticle enhanced ionic liquid heat transfer fluids". United States. doi:. https://www.osti.gov/servlets/purl/1150095.
@article{osti_1150095,
title = {Nanoparticle enhanced ionic liquid heat transfer fluids},
author = {Fox, Elise B. and Visser, Ann E. and Bridges, Nicholas J. and Gray, Joshua R. and Garcia-Diaz, Brenda L.},
abstractNote = {A heat transfer fluid created from nanoparticles that are dispersed into an ionic liquid is provided. Small volumes of nanoparticles are created from e.g., metals or metal oxides and/or alloys of such materials are dispersed into ionic liquids to create a heat transfer fluid. The nanoparticles can be dispersed directly into the ionic liquid during nanoparticle formation or the nanoparticles can be formed and then, in a subsequent step, dispersed into the ionic liquid using e.g., agitation.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Aug 12 00:00:00 EDT 2014},
month = {Tue Aug 12 00:00:00 EDT 2014}
}

Patent:

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  • Interest in capturing the energy of the sun is rising as demands for renewable energy sources increase. One area of developing research is the use of concentrating solar power (CSP), where the solar energy is concentrated by using mirrors to direct the sunlight towards a collector filled with a heat transfer fluid (HTF). The HTF transfers the collected energy into pressurized steam, which is used to generate energy. The greater the energy collected by the HTF, the more efficent the electrical energy production is, thus the overall efficiency is controlled by the thermal fluid. Commercial HTFs such as Therminol{reg_sign} (VP-1),more » which is a blend of biphenyl and diphenyl oxide, have a significant vapor pressure, especially at elevated temperatures. In order for these volatile compounds to be used in CSP systems, the system either has to be engineered to prevent the phase change (i.e., volatilization and condensation) through pressurization of the system, or operate across the phase change. Over thirty years ago, a class of low-melting organic compounds were developed with negligible vapor pressure. These compounds are referred to as ionic liquids (ILs), which are organic-based compounds with discrete charges that cause a significant decrease in their vapor pressure. As a class, ILs are molten salts with a melting point below 100 C and can have a liquidus range approaching 400 C, and in several cases freezing points being below 0 C. Due to the lack of an appreciable vapor pressure, volatilization of an IL is not possible at atmospheric pressure, which would lead to a simplification of the design if used as a thermal fluid and for energy storage materials. Though the lack of a vapor pressure does not make the use of ILs a better HTF, the lack of a vapor pressure is a compliment to their higher heat capacity, higher volummetric density, and thus higher volumetric heat capacity. These favorable physical properties give ILs a pontential advantage over the current commerically used thermal fluids. Also within the past decade nanofluids have gained attention for thermal conductivity enhancment of fluids, but little analysis has been completed on the heat capacity effects of the nanoparticle addition. The idea of ILs or nanofluids as a HTF is not new, as there are several references that have proposed the idea. However, the use of ionic liquid nanofluids containing nanomaterials other than carbon nanotubes has never before been studied. Here, for the first time, nano-particle enhanced ILs (NEILs) have been shown to increase the heat capacity of the IL with no adverse side effects to the ILs thermal stability and, only at high nanoparticle loading, are the IL physical properties affected. An increase of volumetric heat capacity translates into a better heat transfer fluid as more energy is stored per volumetric unit in the solar concentrating section, thus more efficency in increased steam pressure. Results show that the properties of the NEIL are highly dependant on the suspended nanomaterial and careful materials selection is required to fully optimize the nanofluid properties.« less
  • An experimental investigation was completed on nanoparticle enhanced ionic liquid heat transfer fluids as an alternative to conventional organic based heat transfer fluids (HTFs). These nanoparticle-based HTFs have the potential to deliver higher thermal conductivity than the base fluid without a significant increase in viscosity at elevated temperatures. The effect of nanoparticle morphology and chemistry on thermophysical properties was examined. Whisker shaped nanomaterials were found to have the largest thermal conductivity temperature dependence and were also less likely to agglomerate in the base fluid than spherical shaped nanomaterials.
  • Individual coolant passages in the airfoil portion of a liquid-cooled turbine bucket are each provided with a plurality of inwardly protruding circumferentially-extending crimps or rings located at spaced intervals along each passage, each crimp, protrusion or ring extending along the inner periphery in a plane generally perpendicular to the wall of the coolant passage at that location. The main flow of liquid coolant moving in each such individual passage during turbine operation under the combined influence of centrifugal and Coriolis forces is broken up and dispersed over an enlarged area of the interior of the coolant passage upon encountering themore » protrusions.« less
  • The purpose of this study was to investigate the effect of long-term aging on the thermal stability and chemical structure of seven different ILs so as to explore their suitability for use as a heat transfer fluid. This was accomplished by heating the ILs for 15 weeks at 200°C in an oxidizing environment and performing subsequent analyses on the aged chemicals.