Title
Impact of Atmospheric CO2 on Thermochemical Heat Storage Capabilities of K2CO3
Author
Mazur, N.
Huinink, H.
Fischer, H.
Adan, O.
Publication year
2022
Abstract
This work investigates the reactions occurring in K2CO3–H2O–CO2 under ambient CO2 pressures in temperature and vapor pressure ranges applicable for domestic thermochemical heat storage. The investigation shows that depending on reaction conditions, the primary product of a reaction is K2CO3·1.5H2O, K2CO3·2KHCO3·1.5H2O, or a mixture of both. The formation of K2CO3·1.5H2O is preferred far above the equilibrium conditions for the hydration reaction. On the other hand, the formation of double salt is preferred at conditions where hydration reaction is inhibited or impossible, as the thermogravimetric measurements identified a new phase transition line below the hydration equilibrium line. The combined X-ray diffraction, thermogravimetric analysis, and Fourier-transform infrared spectroscopy study indicates that this transition line corresponds to the formation of K2CO3·2KHCO3, which was not observed in any earlier study. In view of thermochemical heat storage, the formation of K2CO3·2KHCO3·(1.5H2O) increases the minimum charging temperature by approximately 40 °C. Nevertheless, the energy density and cyclability of the storage material can be preserved if the double salt is decomposed after each cycle.
Subject
Batteries
Energy storage
Domestic heat storage
Thermochemical heat storage
To reference this document use:
http://resolver.tudelft.nl/uuid:78cb00d3-7f60-4112-8fbb-7ada7b262d83
DOI
https://doi.org/10.1021/acs.energyfuels.2c02886
TNO identifier
978327
Publisher
ACS
ISSN
0887-0624
Source
Energy & Fuels
Document type
article