| Abstract: | An experimental study has been conducted with the aim to investigate and evaluate thermophysical properties of technical grade paraffins appropriate for solar energy storage applications.The results obtained involve the kinetics of phase transition and latent heat of phase change, the thermal cycling stability at heating and cooling and specific heat for the temperature range of application.A method for the automatic computer controlled thermal cycling has been developed. The dynamic mode of precise uniform rising and lowering of the temperature at various rates has been accomplished. Nine hundred thermal cycles have been carried out on two different mixtures of technical grade paraffins, varied by their composition.The change of the DSC kinetics measured by Mettler TA 3000 and the relative thermodynamic values of the phase transitions were not registered after cycling. The calculated enthalpies of three paraffin mixtures were found to depend on their oil content and the distribution of atoms defined by chemical and gas chromatographic analyses. |
