Flow investigation of phase change material (PCM) slurry as a heat transfer fluid in a closed loop system

Aqueous phase change material (PCM) particles are dispersed in an organic phase to constitute a slurry for using as a cold heat transfer medium for district cooling in refrigeration and air conditioning industry. The PCM contains 90% of water stabilized by a three-dimensional network of polymer. The flow behaviour of the slurry is investigated in a small-scale loop circuit with transparent pipes to allow observation of flow patterns. Data show that pressure drop increases with velocity and decreases with temperature, which can be explained by heterogeneities in flow for temperature higher than 0 degrees C and for Reynolds number (based on the properties of the liquid phase) lower than 7000. A homogeneous particle field is observed for Reynolds number up to 7000, which guarantees a safe operation of the system without the occurrence of clogging in ducts. For this range of flow, the flow rate and the pump consumption for the PCM slurry decrease notably for the same heat transportation quantity compared with chilled water. Copyright (C) 2008 John Wiley & Sons, Ltd.