Elasto-Caloric Heat Pump with Variable Pre-Strain for Fatigue Life
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Solution Overview
Problem
Conventional heat pump systems using fluid refrigerants operate at low efficiency and face environmental concerns, while elasto-caloric materials offer higher theoretical efficiency but require impractical and costly mechanical systems for practical use in appliances.
Innovation Solution
An elasto-caloric heat pump system with a pre-strain adjustment mechanism that gradually shifts the elasto-caloric stage's pre-strain over a time interval, increasing fatigue life and efficiency, and can be integrated into appliances like refrigerators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If elasto-caloric materials are used in heat pump systems, then Carnot cycle efficiency is significantly improved, but device complexity and mechanical system requirements worsen
Solution Approach 1:
The patent applies dynamics by making the pre-strain setting of the elasto-caloric stage adjustable and variable over time. The system transitions from static to dynamic operation, allowing the pre-strain to be optimized during different operational phases. This dynamic adjustment enables the system to maintain high Carnot cycle efficiency while reducing mechanical complexity through adaptive control rather than complex mechanical structures.
Solution Approach 2:
The patent changes the pre-strain parameter of the elasto-caloric stage from a fixed value to a variable parameter that can be adjusted over time. By gradually shifting the pre-strain setting away from initial values towards optimized values, the system achieves better efficiency while simplifying the overall mechanical design. This parameter change approach allows optimization of energy loss without requiring complex mechanical systems.
2Adaptability or versatility
If elasto-caloric heat pump systems are designed for appliance use, then application versatility is improved, but fatigue life worsens
Solution Approach 1:
The patent applies preliminary action by gradually shifting the pre-strain setting over a time interval before reaching final optimized values. This gradual transition prevents sudden stress changes that would cause fatigue. By preparing the elasto-caloric stage through progressive adjustment rather than immediate full-load operation, the system extends fatigue life while maintaining versatility for appliance applications.
Solution Approach 2:
The patent implements periodic action through the time-based gradual shifting of pre-strain settings. The system operates through cycles of adjustment, running at multiple pre-strain settings over time intervals. This periodic adjustment pattern distributes mechanical stress more evenly, extending fatigue life while enabling the system to adapt to various appliance applications.
3Ease of manufacture
If conventional fluid refrigerant heat pumps are used, then ease of manufacture is improved, but energy efficiency worsens
Solution Approach 1:
The patent replaces the conventional fluid refrigerant mechanical system with an elasto-caloric material-based system. Instead of using compressors, expansion valves, and circulating refrigerant, the system uses the phase transition and elastic deformation properties of elasto-caloric materials to achieve heat pumping. This substitution maintains ease of manufacture through simpler solid-state components while dramatically improving operational efficiency and reducing energy loss.
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 system achieves up to seven times the fatigue life of traditional elasto-caloric heat pumps and enhances efficiency, making it feasible for appliance use while maintaining high Carnot cycle efficiency.
Implementation Method 1
Elasto-caloric materials (ECMs), i.e. materials that exhibit the elasto-caloric effect, provide a potential alternative to fluid refrigerants for heat pump applications. In general, ECMs exhibit a change in temperature in response to a change in strain.
Data Source
AI summary
A method for operating an elasto-caloric heat pump includes running the elasto-caloric heat pump with a pre-strain in an elasto-caloric stage of the elasto-caloric heat pump set to an initial pre-strain setting, and gradually shifting the pre-strain in the elasto-caloric stage of the elasto-caloric heat pump set away from the initial pre-strain setting and towards a final pre-strain setting over a time interval.