Heat Pipe and PCM Thermal System for Satellite Heat Dissipation
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Solution Overview
Problem
Communication satellites face challenges in effectively cooling thermally sensitive electronics due to limited surface area for heat rejection, particularly in smaller satellites, where heat pipes and phase change materials (PCMs) are used but require optimization for improved thermal management.
Innovation Solution
A combined passive thermal system integrating a heat pipe with a phase change material (PCM) in a single housing, where the heat pipe working fluid is in an inner chamber with a wick for heat transport and the PCM is in an outer chamber, surrounded by fins for increased interface area and improved thermal coupling to a heat sink.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat pipe is used to transport heat from electronics to a radiator, then heat transport efficiency is improved, but the proximity of the phase change material to the heat source is reduced, decreasing thermal management effectiveness
Solution Approach 1:
The patent combines the heat pipe and phase change material into a single integrated housing structure. The heat pipe's evaporator section is positioned in direct thermal contact with the PCM, allowing the PCM to absorb heat directly at the heat source location. This merging eliminates the need for separate heat transport components while maintaining effective heat management.
Solution Approach 2:
The heat pipe is nested within the housing such that its evaporator section is surrounded by or in direct contact with the phase change material. This nested configuration allows the PCM to be positioned at the heat source while the heat pipe's condenser section extends toward the radiator, optimizing both proximity and heat transport pathways.
2Weight of stationary object
If the satellite size is reduced, then mass and volume are decreased, but the surface area available for radiators and thermal control is limited, worsening heat rejection capability
Solution Approach 1:
By merging the heat pipe and PCM into a single housing, the patent creates a compact thermal management system that maximizes heat rejection within minimal space. The integrated design allows the PCM to handle thermal loads close to the heat source while the heat pipe efficiently transports heat to the radiator, achieving effective thermal control in a space-constrained environment.
Solution Approach 2:
The patent applies local quality by positioning the PCM specifically at the heat source location within the housing, creating a localized thermal management zone. This allows efficient heat absorption at the electronics interface while maintaining a compact overall structure, addressing thermal challenges in specific critical areas without requiring uniform thermal control throughout the entire satellite.
3Temperature
If phase change material is used to damp transient temperature extremes, then thermal buffering is improved, but thermal coupling to the heat sink is reduced due to PCM's low thermal conductivity, decreasing heat removal efficiency
Solution Approach 1:
The heat pipe serves as an intermediary between the PCM and the heat sink (radiator). The PCM absorbs heat from the heat source through phase change, and the heat pipe's high thermal conductivity condenser section efficiently transfers this heat to the radiator. This intermediary configuration overcomes the PCM's low thermal conductivity by using the heat pipe's superior heat transport properties for the heat removal pathway.
Solution Approach 2:
The system employs a composite thermal management approach combining PCM (for thermal buffering) with heat pipe materials (for efficient heat transport). This composite configuration leverages the complementary strengths of each material: the PCM's high latent heat for temperature stabilization and the heat pipe's high thermal conductivity for efficient heat removal to the sink.
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 enhances heat transfer efficiency by improving the proximity of the PCM to the heat source, increasing interface area, and optimizing thermal coupling to the heat sink, effectively managing heat dissipation in satellites, especially in smaller designs.
Implementation Method 1
Heat input (i.e., from heat-generating electronics) causes the working fluid to evaporate. The evaporated fluid carries the heat towards a colder heat-output section
Implementation Method 2
The evaporated fluid carries the heat towards a colder heat-output section, where heat is rejected as the fluid condenses
Implementation Method 3
The condensate returns to the heat input section (near to heat-generating components) by capillary forces to complete the cycle
Implementation Method 4
The PCM absorbs heat via the latent heat of fusion; that is the PCM melts. The heat is absorbed without an appreciable temperature rise
Implementation Method 5
A PCM is used to damp transient temperature extremes by storing heat when the thermal load is high and releasing heat when the thermal load is low
Implementation Method 6
The exterior of the first chamber has fins, etc., that extend into the PCM for heat spreading and increased interface area
Implementation Method 7
The rejected heat is absorbed by the cooler surfaces of the heat-output section and then radiated into space
Data Source
AI summary
A passive thermal system for use in a satellite and other aerospace applications includes a container having a heat-pipe working fluid disposed in a first chamber and a Phase Change Material (PCM) disposed in a second chamber that substantially surrounds the first chamber. The first chamber contains a wick for transporting the heat-pipe working fluid. The exterior of the first chamber has fins, etc., that extend into the PCM for heat spreading and increased interface area.