Elasto-caloric heat pump system
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Solution Overview
Problem
Conventional heat pump systems using fluid refrigerants operate at low efficiency and face environmental concerns, with elasto-caloric materials offering a potentially more efficient alternative but requiring practical and cost-effective equipment solutions for applications like appliance refrigeration.
Innovation Solution
A caloric heat pump system featuring a plurality of rotatable elasto-caloric stages with hubs, rims, and spokes, distributed within a housing chamber, utilizing a working fluid to transfer heat between hot and cold side heat exchangers, allowing for efficient temperature change through strain-induced thermal effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional fluid refrigerant heat pump systems are used, then the system structure is simple and easy to manufacture, but the operating efficiency is low (at best 45% or less of Carnot cycle efficiency)
Solution Approach 1:
The patent replaces the conventional mechanical compression system with an elasto-caloric material-based system. The elasto-caloric spokes undergo phase transformation under applied stress, absorbing and releasing heat without mechanical compression of refrigerant. This substitution achieves higher Carnot efficiency while reducing mechanical complexity through the use of smart materials that perform thermodynamic functions through phase change rather than mechanical work.
Solution Approach 2:
The patent utilizes phase transformation of elasto-caloric materials to change thermal parameters dynamically. By applying stress to transform the phase of elasto-caloric spokes from austenite to martensite (or vice versa), the system achieves significant temperature changes and heat transfer at different stages of the cycle, thereby improving overall efficiency beyond conventional fixed-parameter refrigerant systems.
2Use of energy by moving object
If elasto-caloric materials are used to improve efficiency, then theoretical Carnot cycle efficiency increases significantly, but the equipment becomes more complex and expensive
Solution Approach 1:
The patent divides the heat pump system into multiple discrete elasto-caloric stages, each with spokes of different lengths and materials optimized for specific temperature ranges. This segmentation allows each stage to operate at optimal efficiency for its designated temperature differential, while the modular structure facilitates easier manufacturing and assembly compared to a monolithic complex system.
Solution Approach 2:
The elasto-caloric spokes serve multiple functions simultaneously: they act as structural support elements for the heat exchanger, as the active thermodynamic medium for heat absorption and release, and as the phase transformation material for driving the refrigeration cycle. This multi-functionality reduces the need for separate components, thereby reducing overall equipment complexity despite using advanced materials.
3Use of energy by moving object
If elasto-caloric materials are used for appliance refrigeration, then efficiency improves, but the system may be impractical for compact appliance applications
Solution Approach 1:
The patent employs a compact radial configuration where elasto-caloric spokes are nested between the inner and outer heat exchanger surfaces. The spokes radiate outward from a central hub, with multiple stages arranged concentrically, maximizing heat transfer surface area within a minimal volume. This nested radial architecture enables high efficiency refrigeration suitable for compact appliance applications.
Solution Approach 2:
The patent transitions from conventional planar heat exchanger surfaces to a three-dimensional radial configuration. The elasto-caloric spokes extend radially between heat exchanger surfaces, creating a volumetric heat transfer architecture that achieves high efficiency in a compact form factor suitable for appliances, rather than requiring large planar surfaces.
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 higher theoretical efficiency and cost competitiveness by leveraging the elasto-caloric effect, providing a practical and efficient heat transfer solution for refrigeration and potentially other cooling applications.
Implementation Method 1
ECMs exhibit a change in temperature in response to a change in strain
Data Source
AI summary
A caloric heat pump includes a plurality of elasto-caloric stages. The plurality of elasto-caloric stages is distributed between along an axial direction within a chamber of a housing. Each elasto-caloric stage includes a hub, a rim and a plurality of elasto-caloric spokes. The plurality of elasto-caloric spokes extend between the hub and the rim along a radial direction. The plurality of elasto-caloric stages is rotatable about the axial direction.