Macroscopic and microscopic investigations of low-temperature thermochemical heat storage reactors: A review

Characteristics of thermochemical energy storage (TCES) reactors for temperatures below 125 °C at microscopic and macroscopic levels are investigated in the present paper. These two aspects address the numerical and experimental analysis when developing a TCES to implement efficient and feasible systems. The geometry of the reactors, as well as the choice of the reactive bed, proved to be important in the microscopic aspect. Powerful software such as Comsol Multiphysics is widely used for simulation works with satisfactory results at the macroscopic scale, thus reducing the gaps between reality and virtual design. This review also establishes a schematic description of the microscopic and macroscopic analysis of TCES systems. Up to now, there was no standard document for TCES reactors simulation. A dashboard to perform open and closed TCES reactors simulation is elaborated and the impact on performance analysis in the process is demonstrated. The commercialization of technology remains a big challenge. Given the issues that still arise from the process (the heat and mass transfer dilemma, the advanced and complex simulation models developed that could never be implemented in real prototypes, the incomplete studies that mostly focused on dehydration process rather than both hydration and dehydration processes, the sudden increase in pressure at the beginning of the dehydration reaction, the overestimation of data and parameters used in the simulation work which leads to an overestimation of the performance of the systems, the lack of laboratory-scale design works, and the risk of material erosion or agglomeration), substantial and realistic solutions have been proposed.