Thermal Energy Storage of Composite Materials Based on Clay, Stearic Acid, Paraffin and Glauber's Salt as Phase Change Materials

Thermal protection and insulation are important problems in many fields such as industry, agriculture and medicine. New composite materials with good thermal storage capacities have become important in the last few decades. The role of these materials is reflected in their ability to store energy and allow it to be reused in some other thermal systems. The aim of this study was to create a new material based on the basically activated bentonite clay. First, the clay was basically activated, resulting in a thick gel. Afterwards, stearic acid, Glauber's salt and active carbon were added, and a heterogeneous gel was obtained as a finished final product. In order to obtain the best heterogeneous gel with satisfactory storage properties, the amount of stearic acid and Glauber's salt was varied. The characterization of the resulting heterogeneous gel was performed by measuring the cooling rate of the gel samples. Compared with stearic acid, Glauber's proved to be more effective. Heterogeneous gel cooling tests have shown that there was a certain proportional dependence between the concentration of stearic acid and the Glauber salt. However, it has been noticed the reduction in the cooling rate. Namely, the increase in stearic acid and Glauber's salt concentration lead to slowing down the cooling rate of the gel. Adding active carbon to the heterogeneous gel also reduced the cooling rate, which indicated that the presence of active carbon in the heterogeneous gel should not be excluded in the future. The advantage of this system is the improvement of the gel thermal characteristics by the presence of water and clay. The gel was reversibly cooled and heated up to 100 degrees C without changing the homogeneous structure. This system can be used as a heat recovery pad, due to its flexible body pillow. It can be very quickly warmed up in a microwave oven if it is packaged in polyethylene packaging.