Active crystallisation control in phase change material thermal storage systems
AssigneeSunamp Limited
InventorsAndrew John Bissell, Maurizio Zaglio, David Oliver, Santokh Singh Gataora
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Abstract
The present invention relates to phase-change materials (PCM) which store and release thermal energy by undergoing melt/crystallisation cycles. More particularly, there is described a thermal storage system where sub-cooled phase change material (PCM) is nucleated via a controlled thermal region(s).
Claims19
A thermal storage system where sub-cooled phase change material (PCM) is nucleated via a controlled thermal region(s), said heat storage system comprising:
- a containment vessel;
- phase change material located in the containment vessel;
- a heat exchanger located inside the containment vessel and immersed in the phase change material, the heat exchanger having an input and an output;
- and
- a maintained cold spot that actively keeps some nucleating agent below its deactivation temperature when the PCM is above or near the deactivation temperature such that the PCM does not exhibit sub-cooling upon discharge,
- wherein the nucleating agent is a specific hydrate and wherein a deactivation process of the nucleating agent is dehydration or melting, and
- wherein nucleating PCM via a controlled thermal region within the containment vessel results in control of nucleation resulting in consistent, predictive and selectable crystallisation of the PCM.
A method for providing a cold spot in a thermal storage system where sub-cooled phase change material (PCM) is nucleated via a controlled thermal region (s), said method comprising:
- providing a containment vessel which has an input and an output;
- locating phase change material in the containment vessel;
- locating a heat exchanger inside the containment vessel and immersing the heat exchanger in the phase change material;
- wherein the phase change material does not exhibit sub-cooling upon discharge due to the presence of a maintained cold spot that actively keeps some nucleating agent below its deactivation temperature when the PCM is above/near the deactivation temperature,
- wherein the nucleating agent is a specific hydrate and wherein the deactivation process of the nucleating agent is dehydration or melting, and
- wherein nucleating PCM via a controlled thermal region within the containment vessel results in control of nucleation resulting in consistent, predictive and selectable crystallisation of the PCM,
- wherein the controlled thermal region is the cold spot and it provides an area for crystal growth, and wherein the cold spot actively protects the nucleating agent by keeping it below its thermally driven deactivation process temperature at all times and the cold spot is maintained by a heat pipe;
- or wherein the controlled thermal region is the cold spot that actively keeps some nucleating agent below its deactivation temperature when the PCM is above/near the deactivation temperature at all times and is maintained by thermal conductive pathway to an area of lower temperature than the PCM;
- and wherein the PCM system does not exhibit sub-cooling upon discharge due to the presence of the maintained cold spot that actively keeps some nucleating agent below its deactivation temperature when the PCM is above/near the deactivation temperature.
Dependencies are inferred from the claim text.