Stirling Engine With Multiple Piston Assemblies for Low-Temperature Heat
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing Stirling engines are inefficient for low-temperature heat sources due to high friction, wear, and thermal conduction losses, and require complex and expensive heat exchangers, making them uneconomical for small-scale power generation.
Innovation Solution
A Stirling engine design with multiple interconnected piston assemblies, each cylinder being entirely 'hot' or 'cold', eliminating kinematic connections and optimizing fluid flow paths for efficient heat exchange, reducing friction, and using parallel conduits for balanced thermal separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional Stirling engine design with single piston assembly is used, then device complexity is reduced, but friction and wear increase leading to lower efficiency
Solution Approach 1:
The single piston assembly is divided into multiple piston assemblies (first, second, and third piston assemblies) with separate pistons in different cylinders. Each piston assembly operates independently, reducing the friction and wear between moving parts while maintaining the overall engine function. This segmentation allows for reduced friction losses and improved efficiency.
2Use of energy by moving object
If complex heat exchangers are used to improve heat extraction, then heat exchange efficiency increases, but device complexity and cost increase
Solution Approach 1:
The heat exchanger components are extracted and integrated directly into the cylinder structure. The first and second cylinders serve as heat exchangers themselves, eliminating the need for separate complex heat exchanger assemblies. This integration simplifies the overall device structure while maintaining effective heat extraction capability.
Solution Approach 2:
The cylinders serve dual functions: they contain the working fluid and simultaneously act as heat exchangers. The first cylinder receives heat from a heat source and the second cylinder rejects heat to a heat sink, making the entire engine structure multi-functional and reducing the need for additional dedicated heat exchanger components.
3Productivity
If multiple piston assemblies are used to improve efficiency, then heat exchange efficiency increases, but device complexity increases
Solution Approach 1:
Multiple piston assemblies are merged into a coordinated system where the first, second, and third piston assemblies work together in sequence. The pistons are connected through fluid communication paths that synchronize their motion, allowing the system to achieve high power density while distributing the complexity across multiple simpler, coordinated units rather than one complex assembly.
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
Enhances efficiency and reduces costs by enabling effective heat extraction from low-temperature sources, providing high power density and reduced maintenance needs.
Implementation Method 1
The gas is alternately heated and expanded
Implementation Method 2
A Stirling engine extracts power by utilising the cycle of a fixed mass of gas, known as the working fluid, using the temperature difference between the hot end and cold ends of the device
Implementation Method 3
the gas is alternately heated and expanded, and then cooled and compressed
Implementation Method 4
As the working fluid moves through the regenerator between the hot and the cold side, its heat is transferred into the regenerator's matrix
Implementation Method 5
a high temperature gradient is maintained
Data Source
AI summary
A Stirling engine comprising a first cylinder comprising a piston configured to separate at least two expansion or compression chambers of the first cylinder, and a second cylinder comprising a piston configured to separate at least two expansion or compression chambers of the second cylinder. The pistons of the first and second cylinders are connected, such that the first and second cylinders form a first piston assembly. Each chamber of the first cylinder is fluidly connected to a chamber of a first cylinder of a second piston assembly such that a working fluid to be compressed/expanded can flow between the fluidly connected chambers of the first and second piston assemblies. Each chamber of the second cylinder is fluidly connected to a chamber of a second cylinder of a third piston assembly such that a working fluid to be compressed/expanded can flow between the fluidly connected chambers of the first and third piston assemblies. The first cylinder and the second cylinder of the first piston assembly are each configured as an expansion cylinder or a compression cylinder.