Cold-crystallizing erythritol-polyelectrolyte: Scaling up reliable long-term heat storage material

Ionic cross-linked polyvinyl alcohol tunes vitrification and cold-crystallization of sugar alcohol for long-term thermal energy storage

“…After the storage period of three months, the cold-crystallization heat of the samples was up to 70% of the heat charged during melting, confirming the laboratory scale DSC measurements. 27 Of note, the scaling-up studies on the cold-crystallization of erythritol dispersed in ionically crosslinked polyvinyl alcohol introduced herein are on-going and will be reported in our future work.…”

“…7,8,11 Recently, we have demonstrated that heat can be reliably stored for at least a three-month period without any noticeable decrease in the recovered coldcrystallization heat by scaling up the erythritol dispersed in covalently crosslinked polyacrylate. 27 In the scaling-up process, bulk samples (160 g) were charged with the heat during melting, supercooled and stored at a constant temperature within 0-10°C for up to three months, and finally cold-crystallized for heat recovery via an applied thermal chamber set-up.…”

“…We have recently demonstrated a successful scaling up of this novel methodology as a new class of reliable longterm latent heat storage, enabling the recovery of heat after at least three months of storage by erythritol dispersed in covalently crosslinked polyacrylate. 27 To this end and for the first time, we enable the stable supercooling, vitrification (glass transition), cold-crystallization, and shape-stabilization of sugar alcohols through the incorporation of polyvinyl alcohol (PVA) polymer for LLHS. Most importantly, we further demonstrate that the developed glass-transition and cold-crystallization properties of our novel cold-crystalizing PCM (CC-PCM) can be tuned through the addition and concentration of sodium citrate salt acting as an ionic cross-linker.…”

“…1,3,8,10,15,16 However, these PCMs suffer from several drawbacks including flammability, fossilfuel based origin, large volume change, instability and phase segregation issues, 1,3 while, the CC-PCM developed herein is based on green sugar alcohol PCM with the advantages of biobased origin, non-flammability, nontoxicity, non-corrosiveness, and affordable market price, making them suitable for sustainable applications. 5,6,13,14,27 Most importantly, commonly used PCMs are mainly intended for short-term LHS, from a day up to a week, as they are unable to preserve the stored heat for longer times. 10 On the other hand, the CC-PCM is intended for longer time storage of latent heat (from weeks to seasonal) far below the melting temperature through supercooling and glass transition tendency and the recovery of the stored heat by clod-crystallization.…”

“…10 On the other hand, the CC-PCM is intended for longer time storage of latent heat (from weeks to seasonal) far below the melting temperature through supercooling and glass transition tendency and the recovery of the stored heat by clod-crystallization. 8,27 In this way we can overcome the mismatch between supply and demand for the utilization of intermittent renewable energy, particularly in colder climate with extreme seasonal variation of solar energy. Ideally, we can store the abundant solar heat from summertime for cold wintertime, thus mitigating the climate change by reducing the dependency on fossil fuel-based burning, for example, for domestic heating purposes.…”