Packed Bed Storage Heat Distribution via Particle Size Grading
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Solution Overview
Problem
Thermal energy storage systems face inefficiencies due to natural and forced convection effects during charging and discharging phases, leading to temperature discrepancies and reduced average outlet temperature, particularly in systems with multiple inlets or outlets distributed vertically across the storage medium.
Innovation Solution
A heat storage system with interconnected housing sections and varying sizes of heat storing elements, where the size of the elements and their distribution control the mass flow of the working fluid, using a passive method to regulate thermal exchange and minimize convection, employing diffusor and nozzle profiles to optimize fluid flow and isotherm distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the storage is designed with multiple inlets or outlets distributed vertically over the cross section to segment the working flow, then the storage dynamics and efficiency are improved, but the temperature discrepancies in the inlet and outlet sections increase and the average outlet temperature decreases
Solution Approach 1:
The patent applies local quality by varying the particle size of the storage medium at different vertical locations. Larger particles are placed in lower sections while smaller particles are placed in upper sections. This creates location-specific properties that compensate for the temperature discrepancies caused by multiple inlets/outlets, maintaining better overall temperature uniformity and higher average outlet temperature while preserving the benefits of flow segmentation.
2Volume of stationary object
If the storage cross section area is increased to improve storage capacity, then the storage volume increases, but the mass flow rate distribution over the full cross section becomes more difficult to control
Solution Approach 1:
The patent divides the storage cross section into different vertical zones and assigns different particle sizes to each zone. This local differentiation allows the system to handle larger storage volumes while maintaining controllable mass flow rate distribution. The varying particle sizes create zone-specific flow characteristics that prevent flow maldistribution problems that would otherwise occur in large cross-section storages.
3Ease of manufacture
If heat storing elements of uniform size are used throughout the storage, then the system construction is simplified, but the heat distribution homogeneity and flow distribution deteriorate
Solution Approach 1:
The patent implements local quality by using heat storing elements of different sizes in different vertical locations within the storage. Larger elements are placed in lower sections and smaller elements in upper sections. This non-uniform arrangement improves heat distribution homogeneity and flow distribution characteristics, overcoming the limitations of uniform-size elements while the overall system remains relatively simple to construct.
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 enhances the homogeneity of heat distribution and efficiency by controlling the mass flow and thermal exchange between storage volumes, reducing temperature discrepancies and improving the overall performance of the thermal storage system without active mechanisms.
Implementation Method 1
natural and forced convection effects occurring in the storage medium
Implementation Method 2
natural and forced convection effects occurring in the storage medium
Implementation Method 3
Solid bed storages which use heat capacity of filled material
Implementation Method 4
thermal exchange between storage volumes
Data Source
Figure 1~2
AI summary
It is described a system (100) for storing heat. The system (100) comprises a first housing section (110) with a first storage volume (V1), wherein the first housing comprises a first opening (113) for connecting the first storage volume (V1) to an environment. A first type (111) of first heat storing elements is arranged within the first housing section (110). The system further comprises a second housing section (120) with a second storage volume (V2), wherein the second housing section (120) comprises a second opening (123) for connecting the second storage volume (V2) to the environment, wherein the first storage volume (V1) and the second storage volume (V2) are interconnected for forming a common storage volume. A second type (121) of second heat storing elements is arranged within the second housing section (120). The first heat storing elements of the first type (111) comprise a respective first element size, wherein the second storing elements of the second type (121) comprise a respective second element size. The first element size differs from the second element size.