Fiber-Gradient Regenerator for Higher-Efficiency Refrigeration
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Solution Overview
Problem
Conventional regenerative refrigerators face inefficiencies in accumulating cold thermal energy due to uniform fiber diameters and porosity across the regenerator, leading to suboptimal heat exchange at varying temperatures, resulting in reduced refrigeration efficiency.
Innovation Solution
A regenerative refrigerator design with a sintered body of fiber material having a smaller diameter and lower porosity at the low-temperature end and larger diameter and higher porosity at the high-temperature end, optimizing fluid resistance and heat exchange efficiency across the temperature gradient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform fiber diameter and porosity are used throughout the regenerator, then manufacturing is simplified, but heat exchange efficiency deteriorates at varying temperatures
Solution Approach 1:
The regenerator is designed with non-uniform fiber diameter and porosity distribution along its length. The fiber diameter gradually decreases from the high-temperature end to the low-temperature end, and porosity increases in the same direction. This local variation optimizes heat exchange efficiency at different temperature zones while maintaining manufacturing feasibility through controlled gradient structures.
2Quantity of substance
If larger fiber diameter is used, then fluid resistance decreases, but heat transfer surface area is reduced
Solution Approach 1:
The fiber diameter parameter is continuously varied along the length of the regenerator, creating a gradient structure. This parameter change allows the system to optimize both fluid flow resistance and heat transfer surface area by having larger diameters where flow resistance is critical and smaller diameters where heat transfer surface area is more important.
3Quantity of substance
If higher porosity is used, then fluid flow is improved, but heat accumulation capacity is reduced
Solution Approach 1:
Porosity is varied locally along the regenerator length, with higher porosity at the high-temperature end to facilitate fluid flow and lower porosity at the low-temperature end to maximize cold thermal energy accumulation. This spatial differentiation of porosity resolves the contradiction between fluid flow and heat accumulation.
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
This design enhances the accumulation of cold thermal energy, improving refrigeration efficiency by minimizing heat loss and maximizing heat transfer, as demonstrated by increased refrigeration capacity compared to conventional systems.
Implementation Method 1
the regenerative material is cooled by the cooled working gas returning to the compressor, and also refrigerates the working gas flowing into the pulse tube
Implementation Method 2
the regenerator being loaded with a regenerative material to accumulate cold thermal energy from the cold thermal mass in the working gas
Implementation Method 3
a sintered body made of a fiber material, and a diameter of the fiber material disposed at a low-temperature end of the regenerator is smaller than a diameter of the fiber material disposed at a high-temperature end of the regenerator
Implementation Method 4
maximizing heat transfer, as demonstrated by increased refrigeration capacity compared to conventional systems
Data Source
AI summary
A regenerative refrigerator includes a regenerator disposed in a flow passage of working gas generating a cold thermal mass, the regenerator being loaded with a regenerative material to accumulate cold thermal energy from the cold thermal mass in the working gas, wherein the regenerative material is a sintered body made of a fiber material, and a diameter of the fiber material disposed at a low-temperature end of the regenerator is smaller than a diameter of the fiber material disposed at a high-temperature end of the regenerator.