Nested CO2 Power Cycle Using External Heat Source for Efficiency
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Solution Overview
Problem
Current power production systems using CO2 as a working fluid face limitations in efficiency and power output while also emitting CO2, NOx, and other combustion products into the atmosphere, despite efforts to optimize recuperative heat exchangers and external heat sources.
Innovation Solution
The system employs an independent heat source to heat a high-pressure CO2 stream from a power production cycle, which is then expanded and recombined with the primary cycle to enhance heating and power production, utilizing shared equipment and external heat sources such as gas turbines or solar heat to increase efficiency and reduce emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If external heat sources are used to heat compressed CO2 stream, then power production efficiency and output increase, but system complexity increases
Solution Approach 1:
The patent implements a nested cycle configuration where a second power production cycle is embedded within the first cycle. The second cycle processes a portion of the compressed CO2 stream from the first cycle, heating it with an independent external heat source, expanding it through a second expander, and returning it to the first cycle. This nesting allows the system to generate additional power from the same CO2 stream without requiring completely separate systems, thereby increasing power production efficiency while managing system complexity through integrated design.
2Power
If additional heating is supplied to compressed CO2 stream, then power output increases, but energy loss increases
Solution Approach 1:
The patent ensures continuous useful action by creating a closed-loop nested cycle where the CO2 stream is continuously circulated between the first and second cycles. The second cycle takes a portion of the compressed CO2, adds heat from an external source, expands it to generate additional power, and returns it to the first cycle. This continuous circulation ensures that the added heating consistently contributes to power generation without energy loss, as the heated stream remains within the productive cycle rather than being discharged or requiring re-compression from ambient conditions.
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 approach significantly increases power production efficiency and output while minimizing atmospheric emissions by leveraging external heat sources to provide additional heating beyond internal recuperation, reducing capital expenditures and maintaining high efficiency.
Implementation Method 1
an independent heat source can be used to heat at least a portion of a high pressure recycle CO2 stream from the power production cycle
Implementation Method 2
the so heated stream can be rejoined to the power production cycle in a variety of manners to achieve the additional heating of the recycle CO2 work stream. Advantageously, the so-heated recycle CO2 stream can be expanded for additional power production
Implementation Method 3
receiving the heat that is provided to the compressed recycled CO2 in the second power production cycle
Data Source
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AI summary
The present disclosure relates to systems and methods useful for power production. In particular, a power production cycle utilizing CO2 as a working fluid may be combined with a second cycle wherein a compressed CO2 stream from the power production cycle can be heated and expanded to produce additional power and to provide additional heating to the power production cycle.