Two-Side Flat Evaporator Reducing Parasitic Heat Leak

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Solution Overview

Problem

Existing flat two-side evaporators in heat loops suffer from reduced compactness, increased parasitic heat leak, and decreased effective thermal conductance due to the internal location of the compensation chamber and the inability to use one interface plate as a heat sink.

Innovation Solution

The design incorporates two high thermal conductivity interface plates with a surrounding low thermal conductivity envelope, a wrap-around compensation chamber inside the envelope, and vapor grooves between the interface plates and the wick, which enhances compactness, reduces parasitic heat leaks, and improves thermal conductance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the compensation chamber is located inside the wick, then the evaporator structure is compact, but the overall thickness increases and parasitic heat leak increases

Engineering Contradiction:
Improveevaporator structure compactnessVSAvoidparasitic heat leak
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The compensation chamber is extracted from the internal wick location and relocated to the peripheral region of the evaporator. This extraction eliminates the parasitic heat leak path through the wick while maintaining structural compactness through optimized peripheral positioning.

Inventive Principle:
Principle #2Taking out (Extraction)

2Device complexity

If the compensation chamber is located inside the evaporator, then the structure is integrated, but thermal conductance decreases due to increased heat leak

Engineering Contradiction:
Improvestructure integrationVSAvoideffective thermal conductance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The compensation chamber is extracted from the core evaporator structure and positioned peripherally. This maintains functional integration while eliminating the heat leak pathway that reduced thermal conductance, thereby improving reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If one interface plate is used as heat sink, then thermal management is improved, but the current design prevents this functionality

Engineering Contradiction:
Improvethermal management capabilityVSAvoidinterface plate functionality
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The interface plates are designed with universal functionality, allowing one interface plate to serve dual purposes as both a thermal interface and a heat sink. This multi-functionality enhances thermal management capability while maintaining design flexibility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 configuration improves the compactness of the evaporator, reduces parasitic heat leaks, and enhances the effective thermal conductance of the heat loop, preventing fluid circulation stoppage and ensuring reliable operation.

Implementation Method 1

a surrounding low thermal conductivity envelope, wherein the low thermal conductivity envelope has an upper part and a lower part and an evaporator's side wall

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

A capillary pump (wick) in the evaporator provides liquid return from a condenser

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 3

Heat transfer in a HL is provided by evaporation-condensation cycle

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 4

Heat transfer in a HL is provided by evaporation-condensation cycle

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP4538626A1A two-side flat evaporator
Publication Date: 2025.04.16 ALLATHERM SIA
  • EP4538626A1 patent drawingFigure 1
  • EP4538626A1 patent drawingFigure 2
  • EP4538626A1 patent drawingFigure 3

AI summary

The invention relates to a flat loop heat pipe evaporator, which may be used for aerospace or terrestrial electronic equipment cooling and thermal management. A two-side flat evaporator comprises a casing comprising two high thermal conductivity interface plates (101, 102), and a surrounding low thermal conductivity envelope (103); wherein the low thermal conductivity envelope (103) has an upper part (119) and a lower part (120) and an evaporator's side wall (115); a wick (111), placed in the space between the interface plates (101, 102) and partially inside the low thermal conductivity envelope (103); a liquid line port (118) crossing the wrap-around vapor collecting gap (108); a compensation chamber designed in the form of an wrap-around compensation chamber (112) surrounding the wick (111) and placed inside the low thermal conductivity envelope (103).