Latent Heat Storage Particle Coating via Airflow Impact
Solution Overview
Problem
Existing methods for producing latent heat storage particles face challenges such as the need for chemical conversion coating treatment and high-temperature firing, difficulty in microencapsulating metal-alloy PCM without Al, and issues with stability and leakage during heat storage cycles.
Innovation Solution
The development of a latent heat storage particle with a core particle made of elements like Al, Mg, Si, or their alloys, coated with a covering portion composed of inorganic compounds that do not chemically react with the core at operating temperatures. This is achieved through a high-speed airflow impact method that secures child particles to the core particles, eliminating the need for separate shell preparation and ensuring a stable structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemical conversion coating treatment and high-temperature firing are used to produce latent heat storage particles, then the coating provides good protection, but the production process becomes complex and requires high-temperature equipment
Solution Approach 1:
The patent extracts the essential function of coating formation by removing the complex chemical conversion coating treatment and high-temperature firing steps. Instead, it uses simple mechanical hybridization where alumina particles are physically mixed and adhered to the PCM surface through high-speed airflow impact, achieving protection without the complex chemical processes.
Solution Approach 2:
The patent replaces the chemical-mechanical coating process (chemical conversion coating followed by mechanical firing) with a purely mechanical hybridization process. The alumina particles are attached to PCM particles through mechanical impact and adhesion in a high-speed airflow field, eliminating the need for chemical reactions and high-temperature firing.
2Manufacturing precision
If separate shell preparation and accommodation steps are used to encapsulate PCM, then the encapsulation structure is well-defined, but the manufacturing process becomes more complex
Solution Approach 1:
The patent merges the shell preparation step and the encapsulation step into a single hybridization process. Alumina particles are directly mixed and adhered to PCM particles in one operation, eliminating the need for separate shell fabrication and assembly steps. The coating particles serve as both the shell material and the encapsulation medium simultaneously.
Solution Approach 2:
The patent segments the encapsulation process at the particle level rather than requiring macro-scale shell fabrication. Individual alumina particles are attached to individual PCM particles, creating encapsulated structures through bottom-up assembly rather than top-down shell formation, which simplifies the overall manufacturing process.
3Ease of manufacture
If metal coating is used for PCM encapsulation, then the coating process is simple, but the heat resistance of the coating is low and it cannot maintain stability at high temperatures
Solution Approach 1:
The patent uses alumina (aluminum oxide), a ceramic material with excellent high-temperature stability and chemical inertness, as the coating material. Alumina particles form a protective shell around the PCM that can withstand high temperatures without degrading, unlike metal coatings that may oxidize or lose structural integrity at elevated temperatures.
4Reliability
If ceramic materials are used for the outer shell to improve heat resistance and corrosion resistance, then the performance is excellent, but the materials are difficult to mold and process
Solution Approach 1:
The patent changes the scale parameter from macro-scale ceramic shell fabrication to micro-scale particle hybridization. Instead of molding and processing ceramic materials into large encapsulation shells, the invention uses pre-formed alumina particles that are naturally suited for direct attachment to PCM particles, eliminating the need for complex ceramic molding and processing operations.
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
This approach effectively suppresses PCM leakage and maintains a stable structure even after multiple heat storage cycles, while also simplifying the production process by eliminating the need for high-temperature firing and complex shell preparation.
Implementation Method 1
a step of causing the core raw material particle and the child particle to collide with each other by a high-speed airflow impact method
Implementation Method 2
the latent heat storage technology uses a solid-liquid phase change latent heat of a phase change material (PCM)
Implementation Method 3
The oxide film can be chemically stable
Data Source
AI summary
A latent heat storage particle that comprises a core particle and a coating part covering at least a part of the surface of the core particle, wherein: the core particle is composed of an element selected from the group consisting of Al, Mg, Si, Ti, Fe, Ni, Cu, Zn, Sn, Sb, Ga, In, Bi, Pb and Cd or an alloy or a compound mainly composed of the same and has a melting point of 100° C. or higher; the coating part is composed of one or more selected from the group consisting of an element different from the component of the core particle, an alloy and an inorganic compound containing the element and a mixture thereof, which does not undergo a chemical reaction with the core particle in the temperature range of the operating temperature; and at least a part of the coating part is in a particulate shape.