CO2 Rankine Cogeneration Loop for Pump-Free Fluid Circulation
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Solution Overview
Problem
Existing cogeneration systems face inefficiencies and safety concerns due to the use of hazardous working fluids, particularly in smaller-scale applications, and often experience losses in phase change and heat transfer, limiting their use to industrial and large-scale operations.
Innovation Solution
A cogeneration system utilizing carbon dioxide (CO2) as a non-hazardous working fluid, operating through a Rankine cycle with a conduit loop, valve system, and heat exchangers, which allows for efficient energy transfer without mechanical pumps, and includes features like backflow vapor lines and dual heat exchangers for enhanced efficiency and versatility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If hazardous working fluids are used in cogeneration systems, then energy transfer efficiency is improved, but safety and applicability to smaller-scale operations deteriorate
Solution Approach 1:
The patent changes the physical and chemical parameters of the working fluid by using CO2 instead of traditional hazardous fluids. CO2 operates at lower temperatures and pressures, fundamentally altering the operating parameters to achieve both high efficiency and safety for smaller-scale applications
Solution Approach 2:
The patent employs CO2, an abundant, non-toxic, and environmentally friendly substance that can be readily available and safely disposed of or recycled, replacing expensive and hazardous working fluids that require special handling and disposal procedures
2Ease of operation
If mechanical pumps are used to pressurize working fluid, then fluid circulation is improved, but system complexity and energy consumption increase
Solution Approach 1:
The patent replaces the mechanical pump system with a thermodynamic approach where CO2 is pressurized through compression and phase change mechanisms inherent to the Rankine cycle, eliminating the need for separate mechanical pumping components and reducing overall system complexity
Solution Approach 2:
The CO2 working fluid self-pressurizes through the thermodynamic cycle processes, utilizing its own phase transitions and compression characteristics to circulate through the system without requiring external mechanical pumping assistance
3Productivity
If higher temperatures and pressures are used for energy conversion, then power generation efficiency is improved, but system safety and suitability for residential applications deteriorate
Solution Approach 1:
The patent optimizes the temperature and pressure parameters of the CO2 working fluid to operate within safe ranges suitable for residential applications while maintaining efficient power generation. The critical point of CO2 (31°C, 73 atm) provides natural parameter boundaries that ensure safe operation
Solution Approach 2:
CO2 provides inherent safety through its non-flammable, non-toxic properties, allowing the system to operate at efficient temperatures and pressures without the safety concerns associated with hazardous working fluids, making it suitable for residential deployment
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 efficiency and safety in smaller-scale applications, enabling power generation and heat utilization suitable for residential, automotive, and portable power supplies, with CO2 operating at lower temperatures and pressures, reducing the need for mechanical pumps and enhancing energy conversion.
Implementation Method 1
During transport, the working fluid may experience losses in phase change and/or through heat transfer to the environment
Implementation Method 2
Heat may be removed from the system via a cooling coil that returns the working fluid exiting the turbine to a low-temperature and pressure state
Implementation Method 3
Heat may be removed from the system via a cooling coil that returns the working fluid exiting the turbine to a low-temperature and pressure state
Implementation Method 4
A cogeneration system as described herein utilizes a working fluid, which may be carbon dioxide (CO2), after pressurization by a pump and heating by a heat source
Implementation Method 5
transfer of energy is highly efficient, as the working fluid is routed through a turbine-based (or other energy conversion device-based) generator with low loss
Data Source
AI summary
Techniques for cogeneration of heat and power are disclosed. A cogeneration system includes: a conduit loop configured to carry a working fluid using a Rankine cycle; a valve system disposed along the conduit loop, including valves configured to manage flow of the working fluid through a chamber; a backflow vapor line disposed along the conduit loop, configured to direct working fluid in a gaseous state to the chamber, such that the working fluid in the gaseous state displaces working fluid in a liquid state in the chamber and the working fluid in the liquid state advances through the conduit loop without requiring a mechanical pump; and a heat exchanger disposed along the conduit loop, configured to extract heat from the working fluid and direct the heat to a practical use.