Heat Storage Tank Separation Means for Thermal Homogeneity

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Solution Overview

Problem

Thermal storage tanks of the dual thermocline type face issues with non-uniform thermal stratification leading to inhomogeneous thermal fronts and the thermal ratchet effect, which affects their performance and longevity due to mechanical stresses on distributors.

Innovation Solution

Incorporating separation means between the solid elements of the strata and the thermally conductive stack to prevent segregation, allowing heat transfer fluid circulation while using thermally conductive materials with appropriate coefficients of expansion to reduce mechanical stresses and enhance thermal homogeneity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If thermally conductive stacks are interposed between strata to improve thermal homogeneity, then thermal front uniformity is improved, but solid element segregation occurs between strata and stack

Engineering Contradiction:
Improvethermal front uniformityVSAvoidsolid element segregation
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

A separation means is introduced as an intermediary element between the strata and the thermally conductive stack. This separation means prevents direct contact between solid elements of different components, thereby eliminating segregation while allowing thermal conduction to occur through the stack material itself. The separation means acts as a mediator that resolves the conflict between thermal homogeneity and compositional stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The separation means divides the tank interior into distinct zones: one containing strata and another containing the thermally conductive stack. This segmentation prevents mixing of solid elements while maintaining thermal connectivity through the conductive stack material. The segmentation approach allows each component to maintain its integrity while achieving the desired thermal homogeneity.

Inventive Principle:
Principle #1Segmentation

2Temperature

If enclosure material expands during storage phases, then thermal energy is stored, but mechanical stresses are generated on distributors and enclosure structure

Engineering Contradiction:
Improvethermal energy storageVSAvoidmechanical stresses on distributors
Core Design Contradiction:
TemperatureVSStress or pressure

Solution Approach 1:

The patent utilizes the thermal expansion parameter of the enclosure material as a functional mechanism. During storage phases, the enclosure material expands due to temperature increase, which facilitates thermal energy storage. The design accepts and accommodates this parameter change rather than trying to prevent it, transforming a potential stress problem into a functional thermal storage mechanism.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The design anticipates the mechanical stresses that will occur during thermal cycling and incorporates structural provisions to cushion against these stresses. The enclosure and distributor design includes features that can accommodate expansion and contraction without failure, protecting against the harmful effects of repeated thermal cycling.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Use of energy by moving object

If heat transfer fluid circulates at low speed for effective heat transfer, then heat transfer efficiency is improved, but thermal stratification uniformity deteriorates

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidthermal stratification uniformity
Core Design Contradiction:
Use of energy by moving objectVSTemperature

Solution Approach 1:

The thermally conductive stack acts as an intermediary heat transfer path that complements the low-speed fluid circulation. While the heat transfer fluid moves slowly through the strata, the thermally conductive stack provides an additional heat conduction pathway that enhances thermal homogeneity without requiring high fluid velocities. This intermediary conduction path resolves the conflict between low-speed heat transfer and thermal uniformity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution maintains a homogeneous thermal front and reduces mechanical stresses, improving the tank's performance and extending the service life of distributors by preventing thermal ratchet effects and ensuring efficient heat transfer.

Implementation Method 1

at least one stack of solid elements of a thermally conductive material, the stack being interposed between two successive strata

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the storage material being adapted to store the heat of a heat transfer fluid circulating in the enclosure

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 3

The thermal stratification inside the enclosure 10 leads to the presence: a hot zone in an upper part of the enclosure 10, a cold zone in a lower part of the enclosure 10

Methodology Applied
Scientific EffectThermal stratification: Convection

Data Source

PatentEP3311091B1Heat storage tank
Publication Date: 2019.04.03 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3311091B1 patent drawingFigure 1~3
  • EP3311091B1 patent drawingFigure 4~6
  • EP3311091B1 patent drawingFigure 7~9

AI summary

Said tank (1) comprises a chamber (10) including an inner surface (100) defining a space for heat storage, strata (2) 5 of solid elements made of a storage material, the storage material being suitable for storing heat from a heat-transfer fluid flowing in the chamber (10), the strata (2) occupying the space of the chamber (10), and at least one stack (3) of solid elements made of a heat-conductive material. The stack (3) is placed between two consecutive strata (2). The tank 10 (1) is characterized in that it comprises separation means designed to separate the solid elements of the strata (2) and the solid elements of the stack (3), and in that the separation means are designed to allow flow of the heat-transfer fluid through the stack (3).