Fluidized Sand Heat Storage Layout for Low-Energy Heat Transfer

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Solution Overview

Problem

Existing sand-based heat storage systems face inefficiencies due to the need for large sand transport distances, energy consumption in pneumatic conveying, and issues with corrosion and contamination in solar power plants.

Innovation Solution

A heat storage system using sand as a solid medium, featuring a cold and hot sand storage tank, an intermediate fluidized bed heat exchanger with adjustable weirs, and a fan for fluidization, allowing for energy-efficient sand transport and heat transfer within a closed system, eliminating the need for mechanical components and reducing space requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If sand is transported over long distances between heat absorption and heat emission locations, then heat storage capacity is maintained, but energy consumption increases significantly

Engineering Contradiction:
Improveenergy consumptionVSAvoidsand transport distance
Core Design Contradiction:
Loss of energyVSLength of moving object

Solution Approach 1:

The patent combines the sand storage function and heat exchange function into a single integrated structure. The fluidized bed heat exchanger serves dual purposes: it is both the heat exchange medium and the sand storage location, eliminating the need for separate transport pipelines and reducing sand transport distance to minimal levels within the heat exchanger chambers.

Inventive Principle:
Principle #5Merging (Combining)

2Productivity

If pneumatic conveying systems are used to transport sand, then sand can be moved between storage tanks, but a significant proportion of obtained energy is consumed

Engineering Contradiction:
Improvesand transport efficiencyVSAvoidenergy consumption for sand transport
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The system uses the sand itself as the fluidization medium to transport and circulate sand particles. The sand fluidizes and moves through the heat exchanger chambers using its own weight and the fluidization gas flow, eliminating the need for external pneumatic conveying systems and their associated energy consumption.

Inventive Principle:
Principle #25Self-service

3Quantity of substance

If sand is used in solar power plants, then heat storage is achieved, but corrosion and abrasion of components occur

Engineering Contradiction:
Improveheat storage capacityVSAvoidcorrosion and abrasion
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent extracts sand from the external environment and uses only a controlled, closed-loop quantity within the heat exchanger. The sand remains contained within the heat exchanger chambers and does not come into contact with external solar field components, mirrors, or mechanical adjustment mechanisms, thereby eliminating corrosion and contamination problems.

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of operation

If mechanical conveying devices are used for sand transport, then sand can be moved between storage tanks, but mechanical connections become blocked and require maintenance

Engineering Contradiction:
Improvesand transport controlVSAvoidmechanical components for sand transport
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces mechanical conveying devices with a fluidized bed system that uses gas flow to transport and circulate sand. This substitution eliminates mechanical connections, moving parts, and associated maintenance issues, while maintaining controlled sand flow through the heat exchanger chambers.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 system achieves efficient heat transfer and reduced energy consumption by minimizing sand transport distances and eliminating mechanical components, while preventing corrosion and contamination, thus enhancing the overall efficiency and flexibility of heat storage.

Implementation Method 1

at least one fan located below the heat exchanger for fluidizing the sand

Methodology Applied
Scientific EffectFluidization: Fluidisation

Implementation Method 2

means for transferring heat from a heat source to the sand fluidized therein

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 3

means for transferring heat from the sand fluidized therein to a heat transport medium

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Data Source

PatentEP2612098B1Heat storage system
Publication Date: 2015.07.01 VIENNA UNIVERSITY OF TECHNOLOGY
  • EP2612098B1 patent drawingFigure 1
  • EP2612098B1 patent drawingFigure 2
  • EP2612098B1 patent drawingFigure 3a

AI summary

The invention relates to a heat store system using sand as a solid heat storage medium, which heat store system is characterized in that it comprises the following components: a storage vessel (1) for cold sand; a storage vessel (2) for hot sand; an interposed fluidized bed heat exchanger (3) which is separated from the storage vessels (1, 2) by weirs (4, 5) and is divided into a plurality of chambers (7) by weirs (6), wherein the weirs (4, 5, 6) are formed as a combination of overflow and underflow weirs; wherein in the chambers (7) of the heat exchanger (3) there are provided means (8) for transferring heat from a heat source to the sand fluidized therein, and means (9) for transmitting heat from the sand fluidized therein to a heat transport medium; and at least one blower (14), arranged below the heat exchanger (3), for fluidizing the sand.