Characterization of desert sand for its feasible use as thermal energy storage medium

Desert sand samples were thermally analyzed and their suitability for use as sensible heat thermal energy storage (TES) media is evaluated. Mass loss during heating was monitored with a thermal gravimetric analyzer (TGA) linked to a Fourier transform infrared spectrometer (FTIR). This technique showed that the relative mass loss rate of all the samples is comparable and that carbon dioxide is produced during their degradation. The calcite content of each sample is estimated assuming full calcination during the process. Additionally, larger fractions of the samples were heated in a high temperature electric furnace. This experiment showed that some samples tend to agglomerate at high temperatures, thus rendering their use as heat transfer fluid media questionable. Furthermore, color change from lighter tones to whiter tones is observed. This effect may impact the radiative properties of the samples, especially their solar absorptivity values. Finally, the average heat capacity in the 150-1100 degrees C temperature range was measured with a differential scanning calorimeter. The average heat capacity for all the samples was 926.1 J kg(-1) K-1. (C) 2015 The Authors. Published by Elsevier Ltd.