Supercritical Fluid Power System Heat Exchanger Segmentation
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Solution Overview
Problem
Existing supercritical fluid power generation systems face inefficiencies due to the large and expensive heat exchangers required to transfer heat between supercritical fluid cycles and ambient air cycles, limiting thermal efficiency and practicality.
Innovation Solution
A power generation system that splits supercritical fluid discharge streams to flow through separate heat exchangers, allowing for efficient heat transfer and recuperation, thereby reducing the size and cost of heat exchangers by mismatching heat capacity rates and creating a large temperature difference between supercritical fluid and air flows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If heat exchangers are used to transfer heat between supercritical fluid cycles and ambient air cycles, then thermal efficiency is improved, but the size, cost, and weight of the system increase significantly
Solution Approach 1:
The supercritical fluid flow from the compressor is divided into two separate streams: one stream flows through the heat exchanger to transfer heat to the ambient air cycle, while the other stream flows through the recuperator to recover heat from the turbine exhaust. This segmentation allows for optimized heat transfer paths and reduces the overall heat exchanger size required.
Solution Approach 2:
The system utilizes phase changes of the working fluid (between liquid, vapor, and supercritical states) to enable efficient heat transfer. By controlling pressure and temperature parameters, the fluid transitions between phases to maximize heat exchange efficiency while minimizing heat exchanger size.
2Use of energy by moving object
If recuperators are used to recover heat from turbine exhaust, then thermal efficiency is improved, but the temperature difference between hot and cold streams is limited by the compressor discharge temperature
Solution Approach 1:
The compressor discharge stream is split into two separate flows, allowing independent temperature management. One stream can be cooled to a lower temperature in the heat exchanger, creating a larger temperature difference for the recuperator without being constrained by the original compressor discharge temperature.
Solution Approach 2:
The heat exchanger acts as an intermediary device that pre-cools one of the compressor discharge streams before it enters the recuperator. This intermediary cooling step enables the recuperator to operate with a larger temperature difference between the hot turbine exhaust and the cold compressed fluid stream.
3Productivity
If large heat exchangers are used to transfer heat between supercritical fluid and ambient air, then heat transfer efficiency is improved, but the system becomes impractical and expensive
Solution Approach 1:
By dividing the supercritical fluid flow into multiple streams and routing them through different heat transfer paths (heat exchanger and recuperator), the system achieves high overall heat transfer efficiency without requiring a single large, impractical heat exchanger.
Solution Approach 2:
The system exploits phase transitions of the working fluid to achieve highly efficient heat transfer in compact equipment. Phase change heat exchangers provide large heat transfer coefficients and effective heat transfer area in a much smaller volume compared to conventional heat exchangers.
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 reduces the size, cost, and weight of heat exchangers, enhances thermal efficiency, and minimizes thermal signature at exhaust, overcoming the heat pinch point issue in prior art systems.
Implementation Method 1
compressing the supercritical fluid in a supercritical fluid compressor
Implementation Method 2
heat from the mixture of expanded supercritical fluid is transferred to the mixture of compressed supercritical fluid
Implementation Method 3
the mixture of compressed supercritical fluid is directed through one of the plurality of heat exchangers arranged in series and into an inlet of a supercritical fluid turbine, such that heat from combustion gas is transferred to the mixture of compressed supercritical fluid
Implementation Method 4
heat from combustion gas is transferred to the mixture of compressed supercritical fluid
Implementation Method 5
combusting the air to form a combustion gas
Data Source
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AI summary
The present disclosure relates to a power generation system and related methods that use supercritical fluids, whereby a portion of the supercritical fluid is recuperated.