Stirling refrigeration system
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Solution Overview
Problem
Conventional cascade-type refrigeration systems are complex due to the use of a single refrigerant for both low and medium temperature stages, which increases system complexity and environmental impact.
Innovation Solution
A Stirling refrigeration system utilizing a Stirling unit with separate hot and cold circuits for two-phase low Global Warming Potential (GWP) refrigerants, employing thermosyphon effects and pumps for efficient refrigerant flow, and integrating with a medium-temperature vapour compression system for enhanced cooling capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single refrigerant is used for both lower temperature stage and medium temperature stage in cascade-type refrigeration, then the refrigeration system can achieve multi-temperature cooling, but the system complexity increases due to separate compressors and circuit requirements
Solution Approach 1:
The patent divides the refrigeration system into separate hot circuit and cold circuit, each with its own refrigerant loop and temperature control. The hot circuit uses a first refrigerant for medium temperature cooling while the cold circuit uses a second refrigerant for low temperature freezing, allowing independent optimization of each circuit without requiring complex multi-stage compression systems
Solution Approach 2:
The Stirling engine serves multiple functions: it acts as both a heat pump for the hot circuit and a refrigerator for the cold circuit simultaneously. This multi-functionality eliminates the need for separate compressors for different temperature stages, reducing system complexity while maintaining adaptability for various cooling requirements
2Reliability
If conventional vapour compression systems are used for deep freezing applications, then reliable cooling can be achieved, but the environmental impact increases due to high GWP refrigerants
Solution Approach 1:
The patent changes the refrigerant parameter by using low GWP alternatives (such as hydrocarbons or HFOs) in both the hot and cold circuits. This substitution maintains the reliability of cooling performance while significantly reducing the environmental harm associated with high GWP refrigerants used in conventional systems
Solution Approach 2:
The patent replaces the conventional vapour compression mechanism with a Stirling engine-based refrigeration system. This mechanical substitution eliminates the need for high-GWP refrigerants typically required in compression systems, achieving both deep freezing reliability and reduced environmental impact through alternative thermodynamic operation
3Temperature
If separate compressors are used for different temperature stages in cascade refrigeration, then effective cooling at multiple temperatures is achieved, but the system compactness and simplicity are reduced
Solution Approach 1:
The patent merges the functions of multiple compressors into a single Stirling engine unit that simultaneously provides cooling for both hot and cold circuits. This consolidation maintains effective multi-temperature control while significantly improving system compactness by eliminating redundant compression components and interconnections
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 Stirling refrigeration system reduces environmental impact by using low GWP refrigerants and improves efficiency compared to compressor-based systems, achieving effective cooling with reduced complexity and increased compactness.
Implementation Method 1
a hot heat exchanger fluidically coupled to the hot end and configured to release heat from the hot end
Implementation Method 2
a cold heat exchanger fluidically coupled to the cold end and configured to release heat to the cold end
Implementation Method 3
at least one of the first refrigerant and the second refrigerant comprises a two-phase low Global Warming Potential (GWP) refrigerant
Data Source
AI summary
A Stirling refrigeration system is disclosed that comprises a Stirling unit having a hot end and a cold end. In addition, the Stirling refrigeration system includes a hot heat exchanger fluidically coupled to the hot end and configured to release the heat form the hot end, wherein the hot heat exchanger and the hot end define a hot circuit for a first refrigerant to flow therein. Further, the Stirling refrigeration system includes a cold heat exchanger fluidically coupled to the cold end and configured to remove the heat from the cold end, wherein the cold heat exchanger and the cold end define a cold circuit for a second refrigerant to flow therein. One of the first refrigerant and the second refrigerant comprises a two-phase low GWP refrigerant.