Synthesis of Me Doped Mg(OH)₂ Materials for Thermochemical Heat Storage.

Elpida Piperopoulos,Emanuela Mastronardo,Marianna Fazio

doi:10.3390/nano8080573

Abstract

In order to investigate the influence of metal (Me) doping in Mg(OH)2 synthesis on its thermochemical behavior, Ca2+, Co2+ and Ni2+ ions were inserted in Mg(OH)2 matrix and the resulting materials were investigated for structural, morphological and thermochemical characterization. The densification of the material accompanied by the loss in porosity significantly influenced the hydration process, diminishing the conversion percentage and the kinetics. On the other hand, it increased the volumetric stored/released heat capacity (between 400 and 725 MJ/m3), reaching almost three times the un-doped Mg(OH)2 value.

Highlights

The Renewable Energy Directive establishes an overall policy for the production and promotion of energy from renewable sources in the European Union (EU)
The calcium oxide hydration/dehydration reaction is proposed as a suitable reaction couple for thermochemical energy storage systems for its high energy density (0.4 kWh/kg) and low material cost (50 €/t) [13,14,15]
A suitable Thermochemical heat storage (TCS) system storing in lower temperature range between 200 ◦C and 400 ◦C, which has been examined in this study, is the dehydration/hydration reaction of magnesium hydroxide/oxide: Mg(OH)2(s) ↔ MgO(s) + H2O(v) ∆H0 = ±81 kJ/mol

Summary

Introduction

The Renewable Energy Directive establishes an overall policy for the production and promotion of energy from renewable sources in the European Union (EU). Thermal energy storage (TES) transfers heat to storage media during the charging period and releases it at a later stage during the discharging step It can be usefully applied in solar plants, or in industrial processes. Through TES systems, heat can be stored in the form of sensible [2] or latent heat [3] or in the form of chemical energy (thermochemical storage) [4]. Latent heat storage is realized changing a material phase at a constant temperature, while the thermochemical storage promotes a reversible chemical reaction. The calcium oxide hydration/dehydration reaction is proposed as a suitable reaction couple for thermochemical energy storage systems for its high energy density (0.4 kWh/kg) and low material cost (50 €/t) [13,14,15].

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Conclusion