PCM Capsule with Graphite Core and Polypropylene Skin
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Solution Overview
Problem
Existing heat exchange systems in heating systems have limited heat capacity due to the use of conventional heat exchange fluids like water, and previous attempts to enhance this with phase change materials (PCMs) have been hindered by the presence of solvents in the core materials, which inhibit the desired heat storage and phase transition behaviors.
Innovation Solution
A capsule design featuring a core of phase change material, such as salt hydrate, with added graphite for cohesion and heat transfer enhancement, encapsulated in a thin, watertight skin of polypropylene, allowing for improved heat storage and transfer without solvent interference, and arranged in a buffer system to increase heat capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If phase change material is used in the core to enhance heat capacity, then heat storage ability is improved, but solvent interference deteriorates phase transition behavior
Solution Approach 1:
The patent removes the solvent from the core material composition entirely. The core consists solely of phase change material particles (3-5mm diameter) bound together through compression without any solvent medium, thereby eliminating solvent interference with phase transitions while maintaining heat storage capacity
Solution Approach 2:
The patent creates a composite structure where phase change material particles are bound together through mechanical compression to form a cohesive core. This composite approach allows the PCM particles to maintain their phase transition properties while forming a stable, handleable core structure
2Use of energy by moving object
If loose core material is used to allow phase change, then heat transfer is improved, but form retention deteriorates handling ease
Solution Approach 1:
The core material is pre-compressed into a stable, handleable form (spheres, cubes, or irregular shapes) before encapsulation. This preliminary form-giving action maintains the loose particle structure necessary for heat transfer while providing sufficient mechanical stability for handling and processing
Solution Approach 2:
A thin skin (10-600μm thickness) is applied around the compressed core to provide containment and structural integrity. The skin is thin enough to allow heat transfer while providing sufficient mechanical strength for handling the core material
3Use of energy by moving object
If thin skin is used to reduce interference, then heat transfer efficiency is improved, but watertightness deteriorates protection ability
Solution Approach 1:
The skin thickness is optimized to a specific range (10-600μm) that balances heat transfer efficiency with watertight protection. The skin material is selected from thermoplastics with appropriate thermal and barrier properties to achieve both requirements simultaneously
Solution Approach 2:
The capsule structure forms a composite system where the thin thermoplastic skin encapsulates the PCM core, creating a unified structure that provides both thermal efficiency and fluid protection through the synergistic combination of thin-walled containment and phase change material
4Reliability
If multi-part skin structure is used to ensure watertightness, then protection ability is improved, but manufacturing complexity increases
Solution Approach 1:
The skin is applied as a single continuous piece around the core through injection molding, eliminating seams and joints that would require multiple parts. This one-piece construction achieves watertightness while simplifying the manufacturing process to a single molding operation
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 capsule design significantly enhances the heat capacity of the buffer system by preventing solvent contact with the phase change material, ensuring long-term watertight properties and efficient heat transfer, while allowing for easier handling and integration into existing heat exchange systems.
Implementation Method 1
a core (15) of phase change material
Implementation Method 2
phase change materials could be employed to enhance the heat capacity of a buffer
Implementation Method 3
the core comprises graphite. Addition of graphite to the phase change material will enhance cohesion of the phase change material and heat storage and heat transfer through the phase change material
Implementation Method 4
The watertight skin prevents the phase change material from coming into contact with the heat exchange fluid
Data Source
AI summary
The present invention relates to a core of a capsule, capsules having the cores comprising phase changing material (PCM) to be processed to be form retaining in particular during subsequent steps of applying a skin to form the capsule, as well as an assembly of a plurality of such capsules, use thereof in a buffer, and a production method for manufacturing such capsules or assemblies, for instance in strings.