Experimental investigation on heat transfer characteristics in a phase change dispersion.

A Phase Change Dispersion (PCD) consists of a carrier fluid and a dispersed Phase Change Material (PCM) that changes from solid to liquid while absorbing heat at nearly constant temperature. Due to the phase change of the PCM, the PCD is an efficient heat transfer fluid that enables storing latent heat. To use PCD in technical applications, comprehensive understanding of the heat transfer mechanism is required. A test rig to measure bulk fluid and inner wall temperatures of a PCD flowing through a tube under constant heat flux boundary condition is presented. The temperature measurements allows to calculate local heat transfer coefficients and the apparent specific heat capacity of the PCD. Tests with water were performed and verified with known correlations. Preliminary results of experiments with PCD that consists of dispersed paraffin in water are presented and discussed. The comparison to water at the same Reynolds number showed an enlarged heat capacity and heat transfer coefficients.