Title
Encapsulation of Salt Hydrates by Polymer Coatings for Low-Temperature Heat Storage Applications
Author
van Ravensteijn, B.G.P.
Donkers, P.A.J.
Ruliaman, R.C.
Eversdijk, J.
Fischer, H.
Huinink, H.P.
Adan, O.C.G.
Publication year
2021
Abstract
Efficient and cheap storage of energy from renewable resources presents a key technology to facilitate the ongoing energy transition. Storing heat in thermochemical materials (TCMs), such as salt hydrates, provides a promising concept to meet this demand. TCMs can capture heat reversibly and loss-free by relying on equilibrium hydration reactions of the salts. Persistent bottlenecks in the full-scale application of this technology are the low mechanical resilience of salt grains and their tendency to coagulate or dissolve when in contact with water vapor. To overcome this, the salt grains can be encapsulated by a stabilizing polymer coating. Ideal coatings combine high water vapor permeability with reversible deformability to minimize the resistance for water transport and to accommodate the volumetric changes of the TCM during repetitive (de)hydration, respectively. Here, a systematic study into the applicability of commercially available polymers as coating materials is presented. Mechanical analysis and wet-cup experiments on freestanding polymer films revealed that ethyl cellulose-based coatings successfully combine permeability and ductility and meet the engineering demands for domestic TCM-based heat storage applications. The validity of using freestanding films as model system was confirmed by encapsulating granular TCMs in ethyl and hydroxyl propyl cellulose using fluidized bed coating. The permeability was retained and an enhanced structural integrity of the TCM grains during (de)hydration cycles was observed.
Subject
Salt hydrates
Thermochemical materials
Encapsulation
Heat storage
Core−shell
To reference this document use:
http://resolver.tudelft.nl/uuid:83ba6f64-d725-42a3-aa1c-ea181085f369
DOI
https://doi.org/10.1021/acsapm.0c01186
TNO identifier
953247
Publisher
ACS
Source
ACS Applied Polymer Materials, 3 (3)
Bibliographical note
Author version.
Document type
article