Heat Recovery System with Flow-Modifying Structures
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Solution Overview
Problem
Current heat recovery systems from flue gas are inefficient in recovering low-grade heat due to high operating pressures that prevent the use of lower boiling temperatures and increase the risk of explosive bubble growth, limiting the amount of energy that can be recovered.
Innovation Solution
A heat recovery method and system utilizing a heat exchanger with flow-modifying structures in the vaporization chamber that break up the coolant flow, reducing pressure and preventing explosive bubble growth, allowing for lower operating pressures and increased heat recovery efficiency by using a coolant with a lower boiling point, such as a mixture of water and volatile components like methanol or ammonia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high operating pressures are used in the vaporization chamber, then the coolant can maintain liquid form and prevent explosive bubble growth, but the boiling temperature increases and heat recovery efficiency decreases
Solution Approach 1:
The vaporization chamber is segmented into multiple zones with flow-modifying structures (dividers, baffles, or structured surfaces) that break up the coolant flow into smaller streams. This segmentation allows the system to operate at lower pressures while preventing explosive bubble growth through distributed flow paths and controlled vaporization zones.
Solution Approach 2:
The invention changes the flow parameters of the coolant by introducing flow-modifying structures that alter velocity distribution, flow direction, and residence time. These parameter changes enable the coolant to vaporize more efficiently at lower pressures, resolving the contradiction between pressure control and boiling temperature.
2Stability of the object's composition
If high operating pressures are used, then the coolant flow remains stable, but the heat exchange area must be increased to recover the same amount of heat
Solution Approach 1:
The coolant flow is segmented into multiple parallel channels and streams through flow-modifying structures, increasing the effective heat exchange area without requiring a proportionally larger overall heat exchanger. This segmentation maintains flow stability while improving heat recovery efficiency.
Solution Approach 2:
The flow-modifying structures introduce three-dimensional flow patterns including turbulence, recirculation zones, and multi-directional flow paths. This dimensional complexity increases the effective heat exchange area within a compact volume, reducing the need for large heat exchange surfaces.
3Productivity
If the coolant flow is broken up into smaller streams, then heat exchange efficiency increases, but the pressure drop increases
Solution Approach 1:
The flow-modifying structures are strategically positioned to create localized flow patterns that optimize heat exchange in specific zones. By concentrating flow modification effects where heat exchange is most effective, the system achieves high productivity while minimizing overall pressure drop through optimized flow paths.
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 effectively recovers more heat energy as mechanical or electrical work by reducing the boiling temperature of the coolant and minimizing pressure drop, enhancing energy efficiency and reducing the heat exchange area, while avoiding explosive bubble growth.
Implementation Method 1
coolant liquid flows in contact with a heat exchanging wall in heat exchanging contact with flue gas in said flue gas chamber thereby causing vaporization of said coolant liquid
Implementation Method 2
coolant liquid vaporizes in the vaporization chamber to give vapour
Implementation Method 3
using the vapour to drive an expansion device, thereby recovering said heat as mechanical work or electrical energy
Implementation Method 4
condensing the vapour in a condenser downstream of said expansion device to give condensate
Implementation Method 5
pressurizing the condensate in a pump to give pressurized condensate
Data Source
Figure 1
Figure 2A~2C
Figure 3~4
AI summary
A method for recovering heat from a flue gas from an engine and a heat recovery system are described. The method involves contacting coolant in a vaporization chamber with a plurality of flow-modifying structures. The structures are arranged in series in the direction of the flow of coolant liquid and are each configured for modifying the flow of the coolant liquid and the vapour in said vaporization chamber.