Organic phase change materials (PCMs) have relatively high latent heat capacities, are stable, nontoxic, and not corrosive. Having such advantages, organic PCMs shall find applications in many more thermal energy storage (TES) systems. Currently their main handicap is finding a cost-effective, environmentally benign and compatible encapsulation method. This study uses SiO2, which is preferred in several biocompatible applications, as shell material to microencapsulate two different organic PCMs: Paraffin and Stearic acid. Nanocapsules of these PCMs with sizes in the range of 20-700 nm were produced by in situ emulsion interfacial hydrolysis and polycondensation technique. The resulting microencapsulation ratios observed were 11% for paraffin (PA) and 23% for stearic acid (SA). (C) 2016 Elsevier B.V. All rights reserved.