sCO2 Brayton Cycle With Staged Recuperators and Auxiliary Compressors
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Solution Overview
Problem
Existing supercritical carbon dioxide regenerative Brayton cycles with multiple recuperators suffer from suboptimal heat recovery, limiting their energy efficiency in converting thermal energy to mechanical or electrical energy.
Innovation Solution
A new cycle configuration is introduced that calculates the optimum number of recuperators and auxiliary compressors to enhance heat recovery, using a method that iteratively determines the number based on turbine inlet and outlet pressures and efficiencies, and incorporates split factors and pinch values to optimize heat exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the number of recuperators is increased to improve heat recovery, then energy efficiency is improved, but device complexity increases
Solution Approach 1:
The heat recovery process is segmented into multiple stages by dividing the single recuperator into several recuperators arranged in series. Each recuperator handles a specific temperature range of heat exchange, with the first recuperator handling high-temperature heat recovery and subsequent recuperators handling progressively lower temperature ranges. This segmentation allows for more complete heat recovery while maintaining manageable complexity through modular configuration.
Solution Approach 2:
The patent introduces a new dimensional aspect to the cycle configuration by incorporating multiple recuperators in series along the thermal gradient dimension. This creates a staged heat recovery approach that progresses through different temperature levels, effectively adding a thermal staging dimension to the traditional single-stage heat exchange configuration.
2Loss of energy
If auxiliary compressors are added to optimize heat exchange, then energy efficiency is improved, but device complexity increases
Solution Approach 1:
Auxiliary compressors are introduced as intermediary devices between the main compressor and the turbine. These auxiliary compressors serve as mediators that adjust the mass flow and pressure of the working fluid to optimize the heat exchange process in each recuperator stage. The auxiliary compressors enable precise control of thermal gradients and heat transfer rates without requiring complete redesign of the main compression system.
3Loss of energy
If iterative calculation method is used to determine optimum recuperator number, then heat recovery is optimized, but calculation complexity increases
Solution Approach 1:
The patent employs an iterative calculation method that incorporates feedback loops to continuously refine the determination of the optimum number of recuperators. The method calculates heat recovery performance for different configurations, compares results against optimization criteria, and adjusts the configuration accordingly. This feedback-driven approach systematically converges on the optimal solution while providing a structured framework that manages calculation complexity through iterative refinement rather than exhaustive analysis.
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 new configuration significantly improves energy efficiency by up to 3.84% compared to state-of-the-art cycles, enhancing energy generation per operating hour through more efficient heat recovery and reduced inefficiencies from intercooling.
Implementation Method 1
supercritical carbon dioxide stream TI is expanded in a turbine to a pressure between 3 MPa and 10 MPa (stream Recuperator N Hot Inlet (RHIN))
Implementation Method 2
sCO2 stream RHIN is cooled in N recuperators. The optimal number of total recuperators N are put in series, one after the other
Implementation Method 3
sCO2 stream MCI is compressed in the main compressor to the same or higher pressure than the one defined for the turbine inlet
Data Source
AI summary
Method for producing energy by means of a supercritical carbon dioxide (sCO2) regenerative Brayton cycle with N recuperators in series and N or N−1 auxiliary compressors, where N≥3. By using a higher number of recuperators in series and an auxiliary compressor for each recuperator, the heat recovery process is improved and thus the performance of the cycle compared to the cycles of the state-of-the-art.