No abstract

This study presents the energy storage potential of nitrate salts for specific applications in energy systems that use renewable resources. For this, the thermal, chemical, and morphological characterization of 11 samples of nitrate salts as phase change materials (PCM) was conducted. Specifically, sodium nitrate (NaNO3), sodium nitrite (NaNO2), and potassium nitrate (KNO3) were considered as base materials; and various binary and ternary mixtures were evaluated. For the evaluation of the materials, differential Fourier transform infrared spectroscopy (FTIR), scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) to identify the temperature and enthalpy of phase change, thermal stability, microstructure, and the identification of functional groups were applied. Among the relevant results, sodium nitrite presented the highest phase change enthalpy of 220.7 J/g, and the mixture of 50% NaNO3 and 50% NaNO2 presented an enthalpy of 185.6 J/g with a phase change start and end temperature of 228.4 and 238.6 °C, respectively. This result indicates that sodium nitrite mixtures allow the thermal storage capacity of PCMs to increase. In conclusion, these materials are suitable for medium and high-temperature thermal energy storage systems due to their thermal and chemical stability, and high thermal storage capacity.

This is a repository copy of The transition away from chemical flocculants: Commercially viable harvesting of Phaeodactylum tricornutum.

No abstract

In this study, the use of spent diatomite, an industrial waste in the palm oil production process, was evaluated as a support material for phase change materials (PCMs). Calcination tests of the diatomite were carried out at different temperatures (400, 550 and 700 °C) and times (1 and 2 h). For the PCMs preparation, the organic phase, mixtures of palm oil and commercial stearic acid esters, were impregnated on calcined diatomite under vacuum. Differential scanning calorimetry (DSC) analyses were performed in order to select the PCM with the highest latent heat of fusion and a range of phase change temperature corresponding to the thermal comfort range. DSC, TGA and FT-IR analyses were performed before and after the application of 360 thermal cycles to establish the thermal and chemical reliability of the PCM. It was found that 700 °C and 1 h are the best conditions of the calcination process, and the PCM consisting in 100 % methyl esters of commercial stearic acid presented the highest value of latent heat of fusion (34.67 J/g) and a phase change temperature range of 16.4 to 33.5 °C. After the thermal cycles, the results show that the prepared PCMs has thermal and chemical stability.