Heat Pipe Air Conditioning With Caloric Materials for Low-Resistance Cooling

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Solution Overview

Problem

Conventional air conditioning systems face inefficiencies in heat transfer and require hazardous refrigerants, while alternative compressor-free systems using thermoelectric or magnetocaloric materials have limited cooling capacity due to thermal resistance and low efficiency.

Innovation Solution

Integration of electrocaloric or magnetocaloric materials within heat pipes, specifically designed for unidirectional heat transport, enhances heat transfer efficiency by exploiting latent heat and using magnetic or electric fields to manage heat exchange in a cascaded arrangement, increasing cooling capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional compressor-based refrigeration systems are used, then cooling capacity is achieved, but the systems require hazardous refrigerants and have poor heat transfer efficiency

Engineering Contradiction:
Improvecooling capacityVSAvoidhazardous refrigerants
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical parameters of the system by replacing conventional refrigerants with water as the working medium and using electrocaloric/magnetocaloric materials to achieve temperature changes through electric/magnetic field application, eliminating hazardous substances while maintaining cooling capacity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the mechanical compressor-based refrigeration cycle with a heat pipe system utilizing electrocaloric or magnetocaloric materials that respond to electric or magnetic fields, eliminating the need for mechanical compression and hazardous refrigerants

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

2Object-affected harmful factors

If thermoelectric generators or Peltier elements are used instead of compressors, then the system avoids hazardous refrigerants, but the cooling efficiency and temperature rise are relatively small

Engineering Contradiction:
Improvehazardous refrigerantsVSAvoidcooling efficiency
Core Design Contradiction:
Object-affected harmful factorsVSPower

Solution Approach 1:

The patent combines heat pipe technology with electrocaloric or magnetocaloric materials to create a composite system that leverages both the efficient heat transfer properties of heat pipes and the high temperature change capability of caloric materials, achieving superior cooling efficiency compared to standalone thermoelectric elements

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent utilizes phase transitions of the working medium within the heat pipe (evaporation and condensation) to enhance heat transfer, combining this with the phase-like transitions of electrocaloric/magnetocaloric materials under field application to achieve high cooling efficiency

Inventive Principle:
Principle #36Phase transitions

3Loss of energy

If magnetocaloric material is placed in contact with the outer circumference of heat pipes, then heat exchange occurs, but thermal resistance limits the heat transfer characteristics

Engineering Contradiction:
Improveheat exchangeVSAvoidthermal resistance
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent merges the magnetocaloric material directly with the heat pipe structure, integrating the two components into a unified system where the caloric material forms part of the heat pipe wall or is in direct thermal contact, eliminating the thermal resistance of external coupling

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent nests the magnetocaloric material within the heat pipe structure, placing it in the evaporator or condenser sections where it directly interacts with the working medium, allowing the caloric effect to occur within the heat transfer pathway rather than externally

Inventive Principle:
Principle #7Nested doll (Nesting)

4Adaptability or versatility

If heat pipe conducts heat in both directions, then heat transfer is flexible, but unidirectional heat transport is needed to exploit latent heat effectively

Engineering Contradiction:
Improveheat transfer flexibilityVSAvoidcooling capacity
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent segments the heat pipe into distinct functional zones (evaporator section with electrocaloric/magnetocaloric material, adiabatic section, condenser section) that work together in a unidirectional heat flow pattern, enabling effective exploitation of latent heat while maintaining system versatility

Inventive Principle:
Principle #1Segmentation

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 achieves improved cooling and heating efficiency by leveraging the latent heat of the working medium within the heat pipes, allowing for higher cooling capacities and reduced thermal resistance, thereby enhancing the overall performance of air conditioning devices.

Implementation Method 1

By applying an electrical and/or magnetic field to an electrocaloric or magnetocaloric material, this changes its temperature due to the alignment of the electrical or magnetic moments and the associated reduction in entropy

Methodology Applied
Scientific EffectElectrocaloric effect: Electrocaloric Effect

Implementation Method 2

By applying an electrical and/or magnetic field to an electrocaloric or magnetocaloric material, this changes its temperature due to the alignment of the electrical or magnetic moments

Methodology Applied
Scientific EffectMagnetocaloric effect: Magnetocaloric Effect

Implementation Method 3

a liquid working medium is vaporized at a first thermal contact end, also referred to as the evaporator

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 4

the working medium vapor condenses at the other thermal contact end, also referred to as a condenser, of the heat pipe

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 5

heat transfer by phase change releasing the latent heat of vaporization or condensation of the working medium

Methodology Applied
Scientific EffectLatent heat of vaporization: Latent Heat

Implementation Method 6

The liquid working medium can be transported back either by capillary forces ('heat pipe')

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 7

or gravity ('(Two-phase) thermosiphon') happen

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 8

particular care being taken to ensure that the heat pipe conducts heat well in one direction, but practically none in the other, opposite direction Noticeable heat transport takes place ('thermal diode')

Methodology Applied
Scientific EffectThermal diode effect:

Data Source

PatentEP3169946B1Air conditioning device having at least one heat pipe, in particular thermosiphon
Publication Date: 2019.01.16 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3169946B1 patent drawingFigure 1
  • EP3169946B1 patent drawingFigure 2a~2c
  • EP3169946B1 patent drawingFigure 3

AI summary

The invention relates to an air conditioning device having at least one heat pipe (100), in particular thermosiphon, comprising at least one electro- or magnetocaloric material (4) under at least temporary influence of an electrical and/or magnet field, and comprising a heat transfer oriented from one first end to another second end of the heat pipe. A plurality of these heat pipes, having electro- or magnetocaloric materials integrated or arranged therein, are preferably contained, connected in series in a cascade-like manner and optionally connected to one another via heat exchangers or switchable heat flow regulators.