Olefin Block Copolymer Yarns for Elastocaloric Cooling
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Solution Overview
Problem
Existing HVAC technologies are energy-intensive, contribute significantly to greenhouse gas emissions, and face challenges such as high cost, weight, and material limitations in solid-state alternatives like elastocaloric shape memory alloys, as well as poor cycling stability and waste generation in polymer-based solutions.
Innovation Solution
Development of composite polymer fibers, yarns, and textiles with elastocaloric and twistocaloric properties, specifically using olefin block co-polymer (OBC) fibers that exhibit high-performance, durability, and recyclability, and are capable of reversible temperature shifts without strain-induced crystallization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If elastocaloric shape memory alloys are used to achieve large temperature variations and latent heat, then the temperature change and energy storage capacity are improved, but the cost, weight, and required actuating stress increase significantly
Solution Approach 1:
The patent changes the material parameter from metal alloys to polymer materials, specifically using olefin block copolymers that exhibit elastocaloric effects. This parameter change reduces density and cost while maintaining temperature variation capability through phase transitions between amorphous and crystalline states in the polymer chains
Solution Approach 2:
The invention uses composite polymer structures with specific morphologies (spherulitic, lamellar arrangements) to achieve the desired elastocaloric performance. The composite nature of the polymer phases allows for large temperature variations without the weight penalty of metal alloys
2Weight of moving object
If conventional polymer elastomers are used to reduce cost and weight, then material cost and weight are improved, but cycling stability and material durability worsen due to strain-induced crystallization
Solution Approach 1:
The patent modifies the polymer structure from conventional elastomers to olefin block copolymers with specific block arrangements that prevent irreversible crystallization. The parameter change in polymer chemistry allows reversible phase transitions that maintain cycling stability while keeping the material lightweight
Solution Approach 2:
The invention creates local structural features in the polymer (spherulitic domains, lamellar arrangements) that enable reversible crystallization behavior. These localized structural qualities ensure that crystallization and melting occur reversibly during each cycle, preventing material degradation and maintaining reliability
3Quantity of substance
If vapor compression refrigeration is used to achieve cooling, then cooling capacity is maintained, but energy consumption and greenhouse gas emissions increase
Solution Approach 1:
The patent replaces the mechanical vapor compression system with a solid-state elastocaloric system. The mechanical deformation of the polymer material directly induces phase transitions that produce cooling effects, eliminating the need for compressors, refrigerants, and associated energy-consuming mechanical components
Solution Approach 2:
The invention utilizes phase transitions in olefin block copolymers between amorphous and crystalline states to generate cooling effects. When the polymer transitions from crystalline to amorphous phase during deformation, it absorbs latent heat, providing cooling capacity without energy-intensive mechanical compression cycles
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 OBC fibers demonstrate significant temperature changes up to 20°C in the first actuation cycle, with stable operation for over a thousand cycles and a material coefficient of performance (COP) of up to 8, offering a sustainable and efficient alternative for energy conversion and thermal storage systems.
Implementation Method 1
elastocaloric and twistocaloric properties, specifically using olefin block co-polymer (OBC) fibers that exhibit high-performance, durability, and recyclability, and are capable of reversible temperature shifts
Implementation Method 2
elastocaloric and twistocaloric properties, specifically using olefin block co-polymer (OBC) fibers that exhibit high-performance, durability, and recyclability, and are capable of reversible temperature shifts
Implementation Method 3
one or more phase change materials, wherein the one or more phase change materials are dispersed within the polymer matrix
Data Source
AI summary
Compositions and methods for forming composites of polymer fibers, yarns, and textiles having enhanced elastocaloric and twistocaloric performance are provided herein. The composites can permit reversible temperature shifts within the materials, and can be used, for example, in energy conversion and thermal storage systems. These composites can be formulated by melt spinning the polymer fibers and using combinations of twisting and stretching of the polymer fibers. The fibers can include, for example, a base polymer that can be amorphous, or substantially amorphous, and desired alignment can occur, for example, by performing one or more of the various provided for techniques. In at least some embodiments, the composite materials can be further enhanced by including one or more phase change materials (PCMs), such as by cross-linking the one or more PCMs with one or more polymers and/or directly attaching the PCM(s) to the polymer(s).