SOME FATTY-ACIDS AS PHASE-CHANGE THERMAL-ENERGY STORAGE MATERIALS

Thermal energy storage in some fatty acids as phase-change materials has been investigated for a domestic water heating system. The selected fatty acids were myristic acid, palmitic acid and stearic acid, with melting temperatures between 50 and 70-degrees-C. Thermophysical properties of those acids were determined using differential scanning calorimetry (DSC). The density and dilation volumes were determined by a simple dilatometry technique. The degree of degradation after a large number of melting and solidification cycles was examined. Little reduction of the latent heat was found after 450 heating cycles (20-80-degrees-C), while a reduction of up to one-third of the latent heat was found after 21 severe heating cycles (20-150-degrees-C).