Metal PCM Heat Accumulator with Spaced Thermal Coupling

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Solution Overview

Problem

Existing heat storage devices using metallic phase change materials face issues with thermal contact degradation due to volume changes during phase transitions, leading to voids and pores, which affect performance and service life, particularly when using electric resistance heaters.

Innovation Solution

The heat storage device is designed with heat input and output devices arranged partially spaced from the storage material, utilizing thermal bridge elements to maintain thermal contact and prevent void formation, and uses a fiber-reinforced ceramic enclosure to manage thermal expansion differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a heat accumulator device is placed inside a water heater to utilize idle space, then space utilization is improved, but the device temperature may become too high causing safety hazards and reduced service life

Engineering Contradiction:
Improvespace utilizationVSAvoiddevice temperature
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

A heat insulating layer is introduced as an intermediary between the heat accumulator device and the heating element. This insulating layer mediates heat transfer, preventing excessive temperature rise of the device while still allowing efficient heat accumulation during off-peak hours. The insulating layer acts as a thermal buffer that protects the device from direct high-temperature exposure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The heat accumulator device employs composite material construction with a metal shell (steel or aluminum) providing structural strength and thermal conductivity, combined with a heat insulating layer (foam or air gap) providing thermal protection. This composite structure enables the device to withstand high temperatures during operation while maintaining acceptable temperature ranges for safe operation and extended service life.

Inventive Principle:
Principle #40Composite materials

2Use of energy by moving object

If the heat accumulator device is positioned close to the heating element for efficient heat transfer, then heat transfer efficiency is improved, but the device temperature becomes too high causing safety hazards

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidexcessive temperature
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The heat insulating layer is applied locally around the heating element and heat accumulator device interface. This localized insulation ensures that heat transfer efficiency is maintained in the critical heat exchange zones while providing thermal protection where temperature would otherwise become excessive. The insulating material is positioned specifically at the heating element surroundings and device contact areas.

Inventive Principle:
Principle #3Local quality

3Quantity of substance

If the heat accumulator device operates at high temperature for efficient heat storage, then energy storage capacity is improved, but the service life is reduced due to excessive temperature

Engineering Contradiction:
Improveenergy storage capacityVSAvoidservice life
Core Design Contradiction:
Quantity of substanceVSDuration of action of stationary object

Solution Approach 1:

The system dynamically adjusts operating parameters including temperature and heating power based on real-time monitoring. During off-peak hours when electricity is cheaper, the device operates at higher temperatures to maximize energy storage capacity. During peak hours or when temperature thresholds are approached, the system reduces heating power to extend service life. This parameter adjustment strategy balances energy storage efficiency with device durability.

Inventive Principle:
Principle #35Parameter changes

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 design ensures stable thermal contact and prevents material defects, enhancing the service life and performance of the heat storage device by managing volume changes and thermal expansion, allowing high-temperature heat storage up to 1500°C with materials like AlSi12.

Implementation Method 1

a heating element which is arranged to extend into the container and is adapted to heat the liquid in the container to a predetermined temperature

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

a heat accumulator device for storing thermal energy in a liquid in a container

Methodology Applied
Scientific EffectThermal energy storage: Thermal Energy Storage

Implementation Method 3

the liquid is circulated between the container and the heat exchanger

Methodology Applied
Scientific EffectNatural convection: Convection

Data Source

PatentEP4121710B1Heat accumulator device
Publication Date: 2026.05.13 DEUTSCHES ZENTRUM FÜR LUFT UND RAUMFAHRT E V
  • EP4121710B1 patent drawingFigure 1~2
  • EP4121710B1 patent drawingFigure 3
  • EP4121710B1 patent drawingFigure 4

AI summary

The invention relates to a heat accumulator device (100) having a metal phase-change material as an accumulator material (10), the heat accumulator device comprising: - at least one a holding chamber (12) having a holding space (14) for the accumulator material (10); - a housing (16) for the holding space (14); - at least one heat input apparatus (30) for inputting heat into the at least one holding chamber (12); and - at least one heat output apparatus (40) for outputting heat from the at least one holding chamber (12). A coupling region (32) of the heat input apparatus (30), provided for thermal coupling to the accumulator material (10), and/or a coupling region (42) of the heat output apparatus (40), provided for thermal coupling to the accumulator material (10), is arranged, at least in part, at a distance from the accumulator material (10).