Tandem-structured cooling device driven by electrostatic force
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Solution Overview
Problem
Current solid-state electrocaloric cooling devices face challenges in achieving a practical and energy-efficient design with a sufficient temperature span, as they are limited by the adiabatic temperature change of electrocaloric materials and require complex mechanical systems or bulky components for heat regeneration.
Innovation Solution
A solid-state heat transporting cascade device is developed, utilizing flexible electrocaloric elements and heat transfer laminates with electrostatic actuation, where electrocaloric materials absorb or release heat based on an electric field, allowing for antiphase operation of EC elements to expand the temperature span and improve energy efficiency through a compact, cascaded structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If electrocaloric materials are used for solid-state cooling, then cooling efficiency is improved, but temperature span is limited
Solution Approach 1:
The device divides the cooling system into multiple electrocaloric elements (first EC element, second EC element) operating in antiphase. Each element handles a portion of the heat transport cycle, allowing the system to accumulate a larger overall temperature span while maintaining high cooling efficiency of individual EC materials.
Solution Approach 2:
The patent employs periodic application of electric fields to alternate EC elements in an oscillating cycle. During one half-cycle, the first EC element absorbs heat while the second releases heat; during the next half-cycle, their roles reverse. This periodic antiphase operation enables continuous heat pumping across an expanded temperature span.
2Temperature
If mechanical pumps or external motors are used for heat regeneration, then temperature span is expanded, but device complexity increases
Solution Approach 1:
The patent replaces mechanical pumps and external motors with an electrostatic actuation system. Voltages applied to electrode laminates generate electrostatic forces that directly drive the flexible EC elements to move between heat source and heat sink positions. This eliminates bulky mechanical components while maintaining the ability to expand temperature span through coordinated operation of multiple EC elements.
Solution Approach 2:
The electrode laminates serve multiple functions: they generate electrostatic forces for actuation, provide electrical connections for EC elements, and facilitate heat transfer. This multi-functionality reduces the need for separate dedicated components, thereby simplifying the overall device structure while maintaining expanded temperature span capability.
3Temperature
If bulky components are used for heat transfer, then heat regeneration is achieved, but device size increases
Solution Approach 1:
The patent uses flexible electrocaloric elements with thin-film structures that can bend and conform during operation. These flexible elements make direct contact with heat source and heat sink surfaces during heat transfer phases, enabling efficient heat regeneration without requiring bulky heat exchangers or large thermal mass components.
Solution Approach 2:
The patent combines the heat transfer function with the structural framework by integrating electrode laminates and EC elements into a unified cascaded assembly. The same components that provide structural support and electrical actuation also serve as heat transfer interfaces, eliminating the need for separate bulky heat transfer devices and reducing overall device volume.
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 device achieves a significantly enhanced temperature span and energy efficiency by actively transporting heat through electrostatically controlled thermal contact between EC elements, demonstrating improved cooling performance and reduced energy consumption compared to traditional designs.
Implementation Method 1
Cooling based on ECE, which features direct electricity-utilization, is praised for high efficiency, low cost, simplicity in setup, and feasibility for applications at compact scales14,15. The ECE, available in materials such as ferroelectric ceramics and polymers, is a thermodynamic phenomenon where the alignment of dipolar polarization by electric field gives rise to adiabatic temperature change (ΔTECE)15
Implementation Method 2
A solid-state heat transporting cascade device is developed, utilizing flexible electrocaloric elements and heat transfer laminates with electrostatic actuation
Data Source
AI summary
A device comprising one or more heat transfer laminates each including an electrode, a first dielectric layer on a first side of the electrode, and a second dielectric layer on a second side of the electrode; a plurality of flexible electrocaloric elements, each of the flexible electrocaloric elements including an electrocaloric material layer, a flexible electrode layer on the electrocaloric layer, one or more fixed portions each attached to one of heat transfer laminates, and a movable portion that is movable with respect to the one of the heat transfer laminates.