Anomalous enhancements in the specific heat capacity values of nanomaterials were measured in this study. Silica nanoparticles (∼2–20 nm) were dispersed into eutectic of lithium carbonate and potassium carbonate (62:38 by molar ratio) at 1.5% mass concentration. The specific heat capacity measurements were performed using a differential scanning calorimeter (DSC). The specific heat capacity of the silica nanocomposite (solid phase) was enhanced by 38–54% and the specific heat of the silica nanofluid (liquid phase) was enhanced by 118–124% over that of the pure eutectic. Electron microscopy of the samples shows that the nanoparticles induce phase change (forms a higher density “compressed phase”) within the solvent material. Hence, a new model is proposed to account for the contribution of the compressed phase to the total specific heat capacity of the nanomaterials. The proposed model is found to be in good agreement with the experimental data. These results have wide ranging implications, such as for the development of efficient thermal storage systems that can enable significant reduction in the cost of solar thermal power.