Rheological study of TBAB hydrate slurries as secondary two-phase refrigerants

In the refrigeration field, the use of ice slurries (suspensions of ice) as secondary refrigerant fluids is spreading. This technology could be extended to air-conditioning systems provided that one can propose a phase-change material (PCM) with melting temperature belonging to the range [+6 degrees C; +12 degrees C]. Aqueous solutions of tetra butylammonium bromide, which crystallise under atmospheric pressure and temperatures between 0 and +12 degrees C, into ice-like compounds (hydrates), seem to be food candidates for air-conditioning applications. We focus here on the rheological properties of TBAB hydrates suspensions and propose an experimental determination of their flow behaviour through flow rate and pressure drop measurements. In laminar regime, we observe Bingham behaviour. Apparent viscosity and yield shear stress are determined for different hydrate contents. (c) 2005 Elsevier Ltd and IIR. All rights reserved.