Ionic liquid heat-transfer fluids

Van Valkenburg, M.E. et al., Ionic liquid heat transfer fluids, 15th Symposium on Thermophysical Rroperties, Boulder, CO, USA, 2003. 

Van Valkenburg ME, Vaughn RL, Williams M et al. (2005) Thermochemistry of ionic liquid heat-transfer fluids. Thermochim Acta 425 181-188... 

Thermochemistry of Ionic Liquid Heat-Transfer Fluids. 

Robinson, R A. Stokes RH. (1959), Electrolyte Solutions, Butterworths, London, van Valkenburg, M E. Vaughn, R. L. Williams, M. Wilkes, J. S. (2005) Thermochemistiy of ionic liquids heat-transfer fluids. Thermochimica Acta 425, 1-2, 181-188, ISSN... 

Ionic liquids (ILs) are, together with water and supercritical fluids, one of the few alternative media for environmentally friendly processes, which seem to have more possibility of industrial application in the next 10 years. The range of demonstrated or proposed applications of ILs is extraordinary, going from their use as nonvolatile, non-flammable solvents in organic synthesis to catalysts, materials for aiding separations and gas capture, advanced heat transfer fluids, lubricants, antistatics, and so on [2 ]. Surpassing in magnitude the number of potential uses is the number of possible IL compositions, estimated to be in the billions [5]. The term ionic liquids includes all compounds composed exclusively by ions that are liquid... 

Process intensification can be considered to be the use of measures to increase the volume-specific rates of reaction, heat transfer, and mass transfer and thus to enable the chemical system or catalyst to realize its full potential (2). Catalysis itself is an example of process intensification in its broadest sense. The use of special reaction media, such as ionic liquids or supercritical fluids, high-density energy sources, such as microwaves or ultrasonics, the exploitation of centrifugal fields, the use of microstructured reactors with very high specific surface areas, and the periodic reactor operation all fall under this definition of process intensification, and the list given is by no means exhaustive. 

Applications include the use of ionic liquids as electrolytes in electrochemical devices, as solvents in chemical synthesis and catalysis, separation technology, as lubricants and heat-transfer fluids. For the design of separation processes... 

If nanoparticulates in any shapes and structures (e.g., spheres, cylinder or tubes) are dissolved or mixed as a thermally stable suspension in ionic hquids, "bucky gels" termed as "lonanofluids" are formed. These ionanofluids have recently been found to have enhanced thermal conductivity ranging from 2 to 35%, and heat cap>acity compared to their base ionic liquids (Nieto de Castro et al., 2010 Ribeiro et al., 2010). Since these ionanofluids have fascinating features such as high thermal conductivity, high volumetric heat capacity and are non-volatile, they can potentially be used as novel heat transfer fluids. 

Fig. 8. Temperature-dependent heat capacity per unit volume for the ionic liquids and several heat transfer fluids (legend A - [CUmim] [(CF3S02)2N) - [C2mim][C2H5S04] O -[C4mim][dca] A - [Aliquat 336 -derived][dca] —Syltherm800 Syltherm HP —...

The mass production of ionic liquids has not yet been attained however, when it should, we would be able to replace actual non-biodegradable and environmental harmful heat transfer fluids. In addition, due to their increased heat storage capacity as compared with traditional heat transfer fluids, they have the potential to use in shell and tube heat exchangers, and in other small capacity heat exchangers like micro-channels. 

Chen H, He Y, Zhu J et al. (2008) Rheological and heat transfer behaviour of the ionic liquid, [C4mim][NTf2], Int J Heat Fluid Flow 29 (2008) 149-155... 

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