Salt Hydrate PCM Composition for Uniform Crystallization
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Solution Overview
Problem
Salt hydrate-based phase change materials (PCMs) face challenges with crystallization behavior, including issues with crystal growth, supercooling, and non-uniform crystal structures, which affect their performance and reliability in thermal energy storage applications.
Innovation Solution
A PCM composition comprising a salt hydrate, polymeric stabilizer, and non-electrical conducting nucleating agent, including thiosulfate salt hydrate, is developed to enhance crystallization and thermal stability, integrated with a combined electrochemical and thermal storage system for improved energy management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional nucleating agents are used in salt hydrate PCMs, then crystallization is enhanced, but crystal uniformity and thermal stability are compromised
Solution Approach 1:
The patent uses a composite nucleating agent system combining magnesium oxide (MgO) particles with specific surface treatments, creating a multi-component material that simultaneously provides nucleation sites for crystal formation while maintaining thermal stability. The composite structure allows different components to perform specialized functions: MgO provides nucleation, while surface treatments prevent aggregation and maintain uniformity.
Solution Approach 2:
The patent optimizes multiple parameters of the nucleating agent including particle size distribution (0.1-10 micrometers), surface area-to-volume ratio, and surface chemical composition. By carefully controlling these parameters, the system achieves enhanced crystallization kinetics while preventing thermal degradation and maintaining composition stability during phase transitions.
2Quantity of substance
If salt hydrate PCMs are used for thermal energy storage, then latent heat storage capacity is improved, but crystallization behavior issues arise
Solution Approach 1:
The nucleating agents are pre-dispersed and uniformly distributed throughout the salt hydrate PCM matrix before the phase change process occurs. This preliminary distribution of nucleation sites ensures that when crystallization is triggered, it occurs uniformly throughout the material rather than forming large non-uniform crystals, thereby maintaining both high latent heat capacity and crystal structure uniformity.
Solution Approach 2:
The patent introduces nucleating agents at specific locations and concentrations within the PCM to create localized nucleation zones. This ensures uniform crystal formation throughout the bulk material while preserving the overall high latent heat storage capacity of the salt hydrate system. The local addition of nucleating agents prevents the formation of large non-uniform crystals that would reduce manufacturing precision.
3Reliability
If supercooling is reduced in salt hydrate PCMs, then phase transition reliability is improved, but additional additives increase system complexity
Solution Approach 1:
The magnesium oxide-based nucleating agent serves multiple functions simultaneously: it provides nucleation sites for crystal formation, prevents supercooling by ensuring uniform crystallization, and maintains thermal stability during repeated phase transitions. This multi-functionality reduces the need for multiple separate additives, thereby limiting the increase in composition complexity while achieving reliable phase transitions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition achieves uniform phase transitions, reduced supercooling, and enhanced thermal performance, optimizing energy storage efficiency and flexibility, particularly suitable for grid-scale energy management with renewable sources.
Implementation Method 1
These materials undergo a phase change from solid to liquid and vice versa at specific temperatures, thereby enabling thermal energy storage
Implementation Method 2
Phase change materials are utilized in a broad range of applications due to their ability to store and release substantial amounts of energy during phase transitions
Implementation Method 3
Nucleating agents are substances that promote the formation of desired crystalline structures, thereby improving the consistency and efficiency of the phase change process. They function by providing nucleation sites or modifying the physical properties of the PCM to encourage uniform crystal formation
Implementation Method 4
The composition comprises a polymeric stabilizer in an amount of from 0.1 to 20 wt. %
Data Source
AI summary
A phase change material composition for combined electrochemical and thermal energy storage is provided. The composition includes a salt hydrate, a polymeric stabilizer, a nucleating agent, and a thiosulfate salt hydrate. The salt hydrate is present in the composition in an amount of from 0.1 to 99 wt. %. The polymeric stabilizer is present in the composition in an amount of from 0.1 to 20 wt. %. The nucleating agent is present in the composition in an amount of from 0.1 to 20 wt. %. The thiosulfate salt hydrate is present in the composition in an amount of from 0.1 to 25 wt. %. A combined electrochemical and thermal storage system including the phase change material composition is further provided.