Microencapsulated Phase Change Material Thermal Efficiency
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Solution Overview
Problem
Existing microencapsulated phase change materials face challenges in maintaining low free wax, high latent heat, and controlled melt and resolidification points with a minimal temperature difference (ΔT) of 10°C or less, while also ensuring high weight retention and stability in repeated thermal cycles.
Innovation Solution
A microencapsulated phase change material comprising a blend of methyl palmitate and polyethylene, with a core material and a wall material selected from polyacrylate, polymethacrylate, polyamine, polyurea, or melamine formaldehyde, achieving a melt point peak of not more than 30°C and a resolidification peak of not less than 18°C, and a latent heat of at least 165 Joules per gram, along with a Thermal Efficiency Index greater than 0, facilitating high thermal storage density and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional microencapsulation processes are used, then microcapsules can be produced, but the melt point peak and resolidification peak differ by more than 10°C, resulting in poor thermal efficiency
Solution Approach 1:
The patent applies parameter changes by carefully controlling the polymerization conditions, including the ratio of core material to wall material (0.8:1 to 2:1), reaction temperature (70-90°C), and pH conditions (pH 2-4). These parameter optimizations enable the microcapsules to achieve a narrow temperature difference (≤10°C) between melt point and resolidification peak, resolving the technical contradiction between temperature control and thermal efficiency
Solution Approach 2:
The patent uses composite materials by combining phase change materials (fatty acids, esters, or alcohols with specific melting points) with polymer wall materials (polyacrylate, polymethacrylate, polyamine, polyurea, or melamine formaldehyde). This composite structure allows the microcapsules to maintain both the desired phase change temperature characteristics and structural stability through repeated thermal cycles, thereby improving thermal efficiency while ensuring reliability
2Use of energy by moving object
If high latent heat materials are used, then thermal storage density improves, but free wax increases and weight retention decreases
Solution Approach 1:
The patent employs flexible polymer shell structures with wall thickness optimized at 10-50 micrometers. These thin film walls effectively contain the high latent heat phase change materials while preventing excessive free wax formation. The flexible polymer matrix accommodates the phase change material during thermal cycling, maintaining weight retention above 90% after 100 cycles while preserving high latent heat storage density of at least 165 Joules per gram
Solution Approach 2:
The patent optimizes the wall material composition and thickness parameters to balance latent heat storage with free wax control. By adjusting the polymerization conditions and wall material ratio, the microcapsules achieve free wax content below 5% while maintaining weight retention above 90% after 100 thermal cycles, resolving the contradiction between energy storage and substance retention
3Use of energy by moving object
If microcapsules are designed for high thermal storage density, then energy capacity increases, but stability in repeated thermal cycles deteriorates
Solution Approach 1:
The patent creates composite microcapsules with a core of phase change materials (methyl palmitate, ethyl oleate, or lauric acid) enclosed in polymer shells (polyacrylate, polymethacrylate, polyamine, polyurea, or melamine formaldehyde). This composite structure provides both high thermal storage density (≥165 Joules per gram) and excellent cycle stability, with microcapsules maintaining structural integrity and performance through 100 repeated thermal cycles between -10°C and 50°C
Solution Approach 2:
The patent optimizes critical parameters including core-to-wall material ratio (0.8:1 to 2:1), polymerization temperature (70-90°C), and reaction time (2-24 hours). These parameter controls ensure that microcapsules with high thermal storage density maintain compositional stability and structural integrity through repeated thermal cycling, achieving both high energy capacity and long-term reliability
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 provides a microencapsulated phase change material with a low ΔT difference, high latent heat storage density, and improved thermal stability, enabling efficient thermal moderation and retention in repeated cycles, surpassing the performance of current commercial products.
Implementation Method 1
microencapsulated phase change material
Implementation Method 2
latent heat of at least 165 Joules per gram
Data Source
Figure 1
Figure 2
AI summary
The invention discloses a microencapsulated phase change material having a specific Thermal Efficiency Index (TEI). TEl = α(RΔT) * β(RΔH) * y(RMP) * δ(RTGA@180) * e(RFW). The problem of achieving effective and efficient microencapsulated phase change material can be solved to yield a commercially useful material having the described combination of physical and chemical characteristics based on the parameters described in the specification. Microcapsules according to the invention are highly effective at delivering enhanced thermal performance as compared to conventional microcapsules.