Preliminary assessment of a mixture of capric and lauric acids for low-temperature thermal energy storage

A mixture of capric and lauric acids was evaluated as a possible phase- change media suitable for Philippine low-temperature thermal-energy storage systems. The properties of different combinations of acids were verified against existing literature data with the use of a differential scanning calorimeter. Classical evaluation techniques were employed to determine the required thermodynamic, kinetic, and other physical properties. The accuracy of the set-up was determined and phase transitions were observed by performing a series of thermal cycles. To authenticate the long-term stability and reproducibility of the combination, 120 thermal cycles were carried out using a fabricated equilibrium cell. The observed lowest temperatures averaged 11.63°C. The material remained physically stable. However, the energy density requires further design improvement. No usable storage medium has as yet been found because the cooling effect occurred in a time that is too short for practical use.