Physical instability suppression of microencapsulated phase change material(MPCM) suspensions

Physical Instability of the MPCM suspensions tends to suppress suspensions heat transportation in heat exchangers and thermal energy storage tanks The aim of current work is to determine the optimal surfactant and its content, pH-value, and density of the carrier fluid by experimental investigation. In current work, the near infrared transmitting and backscattering fluxes were measured using a universal stability analyzer (TURBISCAN LAb). Such two fluxes characterize the physical stability. It was found, the sodium dodecyl sulfate (SDS) was the better surfactant among the selected surfactants. Experimental data indicates that the optimum SDS mass concentration ratio was 0.2wt.%. The best pH-value was 8 among the selected values. It was also found the MPCM suspension was the most stable at the carrier fluid density of 0.941 g.cm-3. The density difference between the dispersion phase and carrier fluid is the most significant parameter. A near zero density difference, combining the appropriate setup of the other parameters involving surfactant type, its concentration, pH-value, can improve the physical stability of MPCM suspensions significantly, enabling their applications in heat transfer and thermal energy storage.