Influence of thermal treatments on the absorption and thermal properties of a clay mineral support used for shape-stabilization of fatty acids.

Abstract

This paper reports the research carried out about the influence of thermal treatments on the porosity of a powder and granulated clay mineral support, used for shape-stabilization of phase change materials. The supports were calcined at 400 °C, 500 °C, 600 °C, 900 °C, and 1100 °C in order to study their surface area, pore volume, and pore size through Brunauer-Emmet-Teller (BET) and Barrett-Joyner-Halenda (BJH) analysis. Subsequently, the supports were used to prepare several shape-stabilized phase change materials (SS-PCMs) using lauric/myristic acid eutectic. The leakage percentage and thermal properties of the SS-PCMs were measured using the filter paper method and differential scanning calorimetry (DSC), respectively. The powder support calcined at 600 °C presented the best conditions for shape-stabilization with a leakage <2% and a good latent heat of fusion of 51.63 kJ/kg. Moreover, two more SS-PCMs were produced using capric/myristic and palmitic/stearic acids, and the support calcined at 600 °C. The best impregnation percentage found for all the PCMs was 35% wt. Further characterization with modulated DSC (MDSC) was used to determine the heat capacities and a leakage cycling was proposed until 16 h.