Cyclic Assessment of Magnesium Oxide with Additives As a Thermochemical Material to Improve the Mechanical Strength and Chemical Reaction

Heat storage with a thermochemical reaction has the advantages of a high heat storage density and no heat loss compared to conventional methods such as the sensible and latent heat. This method is promising to use in a thermal energy network because it is an efficient solution which addresses the time mismatch problem with regard to heat production and consumption. In this paper, we investigated Magnesium oxide (MgO) with different additives as a thermochemical material (TCM) coupled with the effects of several additives in an effort to improve the structural strength and reaction rate and reduce the initiation time. As additives in an MgO composite, Bentonite, Magnesium sulfate (MgSO4), and Zeolite 13X were chosen. With a cyclic scheduling experimental setup for the heat charging and discharging of the MgO composites, Bentonite as an additive improved the structural strength, and Zeolite 13X enhanced the reaction rate and led to faster reactions compared to only MgO as a TCM. With MgSO4 as an additive, however, the TCM composite showed a high reactivity during the a few cycles, and then rapidly became inactive due to byproducts side reaction. The results indicated that Bentonite and Zeolite additives, in an MgO composite, as a TCM can improve the mechanical strength and chemical reaction, optimum ratio is necessary to compromise promoting the thermochemical reaction.