SiC Heat Storage Member with Coating for Rapid Thermal Response
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Solution Overview
Problem
Conventional chemical heat storage devices face challenges in promptly generating and absorbing heat due to low thermal conductivity of the materials, leading to reduced responsiveness and durability issues when used to heat catalysts for engine startups.
Innovation Solution
A heat storage member with a SiC sintered body substrate and a coating layer containing P2O5, B2O3, or Bi2O3, along with a heat storage material that facilitates rapid heat transfer and chemical reactions, enhancing thermal conductivity and preventing material peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a chemical heat storage material is used to store and radiate heat by reversible chemical reaction, then heat can be stored at relatively high density for a long time, but the responsiveness of heat generation and heat absorption is slow due to low thermal conductivity
Solution Approach 1:
The patent uses a composite structure consisting of a chemical heat storage material (such as calcium oxide or calcium hydroxide) combined with a thermal conductivity enhancement material (such as graphite or metal particles). This composite material allows the system to maintain high heat storage density while significantly improving thermal conductivity and heat generation speed. The thermal conductivity enhancement material forms a network structure that facilitates rapid heat transfer throughout the chemical heat storage material.
Solution Approach 2:
The patent employs porous structures in the chemical heat storage material to increase the surface area available for chemical reactions and heat transfer. The porous structure allows better contact between the chemical heat storage material and the reaction medium (such as water or water vapor), thereby accelerating the heat generation speed while maintaining high heat storage capacity through the reversible chemical reactions occurring throughout the porous network.
2Reliability
If calcium oxide is used as heat storage material with water reaction, then heat can be stored and radiated by reversible chemical reaction, but durability deteriorates due to material aggregation and peeling when repeatedly heating and cooling
Solution Approach 1:
The patent combines calcium oxide or calcium hydroxide with binder materials and structural reinforcement agents to create a composite heat storage medium. This composite structure prevents material aggregation and peeling during repeated heating and cooling cycles by providing mechanical strength and maintaining structural integrity. The binder materials hold the chemical heat storage particles together, preventing them from separating or aggregating during thermal cycling.
Solution Approach 2:
The patent encapsulates the chemical heat storage material in flexible containers or coatings that can accommodate volume changes during thermal expansion and contraction. These flexible shells or thin films prevent direct contact between the chemical heat storage material and the external environment, reducing the risk of peeling and material degradation while allowing the material to maintain its reactive properties.
3Ease of operation
If the heat storage material is made into particulate shape for reaction, then heat can be generated by surface contact with reaction medium, but heat transfer efficiency is reduced due to low thermal conductivity at the particle center
Solution Approach 1:
The patent incorporates thermal conductivity enhancement materials such as graphite flakes or metal particles within the particulate heat storage material. These materials form conductive pathways throughout the particle structure, enabling efficient heat transfer from the reactive surface to the particle center. This ensures that the entire particle volume participates effectively in heat storage and release, eliminating the thermal conductivity bottleneck at the particle center.
Solution Approach 2:
The patent divides the heat storage material into smaller particles or uses hierarchical particle structures with internal channels or voids. This segmentation increases the surface area to volume ratio, allowing reaction medium to penetrate deeper into the particle structure and enabling more uniform heat distribution. The segmented structure reduces the thermal conductivity limitation by shortening the heat transfer path length from surface to center.
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 solution achieves highly responsive heat radiation and absorption, improving durability by ensuring efficient heat transfer and maintaining a high-temperature state, thus addressing the limitations of conventional chemical heat storage devices.
Implementation Method 1
a chemical heat storage material, as the heat storage material, configured to store and radiate heat by a reversible chemical reaction with a reaction medium
Implementation Method 2
Adding water to calcium oxide forms calcium hydroxide (Ca(OH) 2 ) and radiates heat of reaction at the same time. In other words, this reaction is called an exothermic reaction.
Implementation Method 3
adding heat to calcium hydroxide causes dehydration reaction of the calcium hydroxide and forms calcium oxide (CaO) and water (H 2 O). This reaction is called an endothermic reaction.
Implementation Method 4
the heat storage material stores and radiates heat by physical adsorption to a reaction medium and by physical desorption from a reaction medium
Implementation Method 5
the heat storage material stores and radiates heat by physical adsorption to a reaction medium and by physical desorption from a reaction medium
Implementation Method 6
A heat storage member with a SiC sintered body substrate and a coating layer containing P2O5, B2O3, or Bi2O3, along with a heat storage material that facilitates rapid heat transfer and chemical reactions, enhancing thermal conductivity
Data Source
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AI summary
A heat storage member including: a substrate 10 containing a SiC sintered body as a principal ingredient; a coating layer 51 disposed at least to a part of surface of the substrate 10; and a heat storage material 50 disposed at least to a part of a surface of the coating layer 51 and configured to store and radiate heat by a reversible chemical reaction with a reaction medium or a heat storage material 50 configured to store and radiate heat by physical adsorption to a reaction medium and by physical desorption from a reaction medium. A softening point of the coating layer 51 is a temperature at 1000°C or less.