Absorption Process in MgCl2-NH3 Thermochemical Batteries With Constant Mass Flow Rate

Abstract

The working principle and performance of thermochemical batteries have been studied before [1–3]. In this paper, the performance of a thermochemical battery based on magnesium chloride and ammonia pair with a constant mass flow rate of ammonia gas is studied. It is shown that controlling the mass flow rate lowers the temperature of the reactive complex and increases the duration of the absorption process. However, it was observed that the reaction becomes mass transfer limited which slows the absorption rate and takes control of the reaction away from the mass flow controller. The progress of the reaction inside the reactor is studied in a single-cell reactor to understand the performance of these thermal batteries. It was shown that a reaction zone starts at the inlet and moves toward the end of the reactor. The mass transfer limited reaction zone movement reduces the absorption rate and temperature in the reaction zone.