Refrigerator appliance
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Solution Overview
Problem
Conventional refrigeration heat pumps using fluid refrigerants operate at low efficiency and face environmental concerns, with magneto-caloric materials offering higher theoretical efficiency but requiring impractical and costly equipment for practical application in appliances.
Innovation Solution
A refrigerator appliance design incorporating a cold side heat exchanger and a regenerator housing with caloric material, where the working fluid flows through the caloric material and is drawn from multiple locations along its length, utilizing a magnetic field to manage heat transfer efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If magneto-caloric materials are used in heat pump systems, then Carnot cycle efficiency is significantly improved, but equipment complexity and cost increase due to requirements for large and expensive magnets
Solution Approach 1:
The regenerator housing is divided into multiple segments or zones along its length, with working fluid drawn from multiple locations rather than a single point. This segmentation allows for more efficient heat exchange across different regions of the caloric material, improving overall system efficiency without requiring larger or more expensive magnets.
Solution Approach 2:
The system implements different working fluid draw locations along the length of the caloric material to optimize local heat transfer conditions. Each location is strategically positioned to maximize the magneto-caloric effect in that specific region, allowing the system to achieve high efficiency without increasing magnet size or cost.
2Loss of energy
If magneto-caloric materials are used in heat pump systems, then theoretical efficiency is improved, but practical application becomes impractical due to equipment size and cost
Solution Approach 1:
By segmenting the working fluid draw locations along the regenerator housing, the system achieves practical appliance-scale dimensions while maintaining high efficiency. The multiple draw points allow compact arrangement of components, making the system suitable for actual appliance installation rather than just theoretical application.
Solution Approach 2:
The working fluid acts as an intermediary that transfers heat between the magneto-caloric material and the refrigeration compartments. By optimizing the working fluid flow paths and draw locations, the system bridges the gap between the high-efficiency magneto-caloric effect and practical appliance requirements, enabling cost-effective implementation.
3Device complexity
If conventional fluid refrigerant heat pumps are used, then equipment simplicity is maintained, but efficiency is limited to about forty-five percent or less of maximum theoretical Carnot cycle efficiency
Solution Approach 1:
The system replaces conventional mechanical compression-based heat pump cycles with a magneto-caloric effect-based cycle. Instead of using mechanical compressors and expanding valves with fluid refrigerants, the system uses magnetic field application to caloric material to achieve phase change and heat transfer, fundamentally substituting the mechanical system with a magnetic-field-based system to achieve higher efficiency.
Solution Approach 2:
The magneto-caloric material undergoes phase transitions when exposed to magnetic fields, enabling efficient heat absorption and release. This phase transition mechanism replaces the compression-expansion phase transitions of conventional refrigerants, allowing the system to achieve Carnot cycle efficiencies significantly higher than the 45% limit of conventional systems while maintaining practical equipment design.
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 design enhances the efficiency and cost-effectiveness of heat transfer in refrigerator appliances, allowing for higher Carnot cycle efficiency and practical use of magneto-caloric materials, improving cooling performance and reducing environmental impact.
Implementation Method 1
Magneto-caloric materials (MCMs), i.e. materials that exhibit the magneto-caloric effect, provide a potential alternative to fluid refrigerants for heat pump applications. In general, the magnetic moments of MCMs become more ordered under an increasing, externally applied magnetic field and cause the MCMs to generate heat. Conversely, decreasing the externally applied magnetic field allows the magnetic moments of the MCMs to become more disordered and allow the MCMs to absorb heat.
Data Source
AI summary
A refrigerator appliance includes a cold side heat exchanger positioned within a cabinet such that a fresh food chamber and a freezer chamber are chillable with air from the cold side heat exchanger. A regenerator housing is connected to the cold side heat exchanger such that working fluid is flowable from the regenerator housing to the cold side heat exchanger. The working fluid is flowable through a caloric material within the regenerator housing. The refrigerator appliance also includes features for drawing the working fluid from the regenerator housing at a plurality of locations along the length of the caloric material.