Fluidized Bed Heat Exchanger for Dry Cooling
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Solution Overview
Problem
Current dry cooling systems for power plants are costly and energy-intensive, leading to reduced efficiency and increased operational expenses, especially in arid climates where water scarcity is a concern, and traditional air-cooled designs face limitations in air-side heat transfer.
Innovation Solution
The use of moving particles in a heat exchanger, such as a fluidized bed or moving bed heat exchanger, to enhance air-side heat transfer by falling particles picking up heat from tubes or plates and being cooled by ambient air, allowing for thermal storage and improved cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional air-cooled heat exchangers with fins and large fans are used, then heat transfer is augmented, but capital and operating expenses increase significantly and energy consumption increases
Solution Approach 1:
The patent replaces mechanical fan-driven air flow with a fluidized bed system where particles are suspended and circulated using air flow through the particle bed. This pneumatic approach eliminates the need for large fans while achieving enhanced heat transfer through the fluidized particles, directly reducing energy consumption and capital costs associated with traditional fan systems
Solution Approach 2:
The invention changes the physical state and flow characteristics of the heat transfer medium from stationary air to fluidized particles. By adjusting air flow rates to achieve fluidization, the system transforms the heat transfer mechanism from conventional convection to particle-based convection and conduction, dramatically improving heat transfer coefficients while reducing the power needed for air movement
2Temperature
If traditional air-cooled heat exchangers are used, then heat rejection is achieved, but capital expenses and operating expenses are high
Solution Approach 1:
The fluidized bed heat exchanger uses air flow to suspend and circulate particles, replacing complex mechanical fan assemblies and finned heat exchanger structures with a simpler pneumatic system. This reduces both capital expenses for equipment and operating expenses for maintenance, while achieving superior heat rejection performance
Solution Approach 2:
The particle bed acts as a porous medium through which air flows, creating extensive surface area contact between the cooling air and heated surfaces. This porous structure eliminates the need for complex fin arrangements while providing efficient heat transfer, simplifying the overall system design and reducing costs
3Quantity of substance
If dry cooling is used instead of wet cooling, then water consumption is reduced, but heat transfer efficiency decreases and costs increase
Solution Approach 1:
The fluidized bed system uses air as the cooling medium, completely eliminating water consumption while achieving enhanced heat transfer through the fluidized particles. The pneumatic circulation of particles provides superior heat transfer coefficients compared to traditional dry cooling, maintaining efficiency without water usage
Solution Approach 2:
By changing from water-based cooling to air-based fluidized bed cooling, the system eliminates water consumption entirely. The parameter change in heat transfer mechanism from conventional air cooling to fluidized particle cooling compensates for the lower thermal conductivity of air, maintaining heat transfer efficiency without requiring water
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 reduces capital and operating expenses by enhancing heat transfer coefficients, decreasing parasitic energy use, and maintaining cycle efficiency during peak temperatures, while also offering a self-cleaning mechanism to reduce maintenance.
Implementation Method 1
particles in contact with the heat transfer surfaces... contacting moving particles with a heat transfer surface of a member to remove heat from a hot fluid
Implementation Method 2
passing a fluid through the particles to remove heat from and cool the particles
Implementation Method 3
The particle storage bin can have one or more internal surfaces to passively conduct heat to external surfaces that can radiate the heat away to the environment
Data Source
AI summary
Apparatus for cooling a hot fluid by transferring heat to particles that are then cooled by air.