Characterization of Alkanes and Paraffin Waxes for Application as Phase Change Energy Storage Medium

Abstract

Latent thermal energy storage is one of the favorable kinds of thermal energy storage methods considered for renewable energy source utilization, as in solar photothermal systems. Heat is stored mostly by means of the latent heat of phase change of the medium. The temperature of the medium remains more or less constant during the phase transition. A large number of materials have been identified for low, intermediate, and high operating temperatures for application as latent thermal energy storage media. In the present paper a method for characterization of alkanes (C1,-C100) and paraffin waxes for application as the low-temperature (298-323 K) phase change energy storage medium is introduced. A computational technique is introduced by which the alkanes and paraffin waxes could be evaluated, and possibly upgraded, as the phase change energy storage media. It is demonstrated that the family of n-alkanes has a large spectrum of latent heats, melting points, densities, and specific heats so that the heat storage designer has a good choice of n-alkanes as storage materials for any particular low-temperature thermal energy storage application. As an example of the proposed method, a particular paraffin wax for which appropriate experimental data are available is analyzed and the results of the analysis are presented.