Empirical equations for viscosity and specific heat capacity determination of fatty acids

- No empirical equations for viscosity nor Cp determination as a function of temperature are found in the literature.
- Fatty acids are one of the most used PCM in thermal energy storage.
- Empirical equations for fatty acids viscosity and Cp calculation are presented.

Phase change materials (PCM) used in thermal energy storage (TES) systems have been presented, over recent years, as one of the most effective options in energy storage. Saturated fatty acids are one of the most used PCM in TES systems, as they have high phase change enthalpy but in addition they do not present subcooling nor hysteresis and have proper cycling stability. The simulations and design of a TES system require the knowledge of the thermophysical properties of materials. Thermal conductivity, viscosity, specific heat capacity (Cp) can be experimentally determined, but these are material and time consuming tasks. To avoid or to reduce them, and to have reliable data without the need of experimentation, thermal properties can be determined by empirical equations. In this paper, three empirical equations are given to calculate the viscosity, solid Cp, and liquid Cp of the whole fatty acid family of PCM.