Variable Heat Rejection Radiator Using Shape Memory Materials
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current thermal control systems for vehicles face challenges in maintaining consistent internal temperatures across varying thermal environments, particularly in space exploration, due to limitations in radiator systems' heat rejection capacity, leading to increased complexity, mass, and cost.
Innovation Solution
A heat rejection system utilizing temperature-sensitive shape memory materials that change shape and emissivity properties in response to temperature changes, passively adjusting heat rejection capacity without active control, by altering the effective view factor and emissivity of the radiator surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a constant area radiator system is used, then the heat rejection capacity is limited, but the system complexity and mass increase to compensate for varying thermal conditions
Solution Approach 1:
The radiator system transitions from a static constant area design to a dynamic variable area configuration using deployable panels and adjustable louvers. The effective radiating area can be dynamically changed by deploying or retracting radiator panels and adjusting louver angles, allowing the system to adapt heat rejection capacity to match varying thermal loads without increasing overall system complexity
Solution Approach 2:
The radiator system is divided into multiple independent deployable panels and adjustable louver sections rather than a single monolithic structure. Each segment can be independently controlled to optimize heat rejection, allowing granular adjustment of the total effective radiating area while maintaining system manageability
2Adaptability or versatility
If a constant emissivity radiator surface is used, then the heat rejection is limited, but active control systems increase complexity and mass
Solution Approach 1:
The radiator surface emissivity is changed from a constant value to a variable parameter through the use of electrochromic materials. These materials can dynamically adjust their optical properties including emissivity in response to electrical signals, allowing the radiator to optimize heat rejection efficiency across different operating conditions without requiring additional mass for active control systems
Solution Approach 2:
The electrochromic radiator surface automatically adjusts its emissivity in response to thermal conditions and control signals, eliminating the need for external actuators or complex control mechanisms. The material itself performs the adaptation function, reducing system mass while maintaining high adaptability
3Adaptability or versatility
If a constant view factor radiator configuration is used, then the heat rejection capacity is fixed, but variable configurations increase device complexity
Solution Approach 1:
The radiator system incorporates adjustable louvers that can dynamically change the view factor between the radiator surface and the external environment. By rotating the louvers to different angles, the effective view factor is adjusted without requiring complex reconfiguration mechanisms, allowing continuous adjustment of heat rejection capacity through simple rotational motion
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 solution enables a high turn-down ratio in heat rejection, reducing complexity and mass, and allowing for efficient thermal management across extreme temperature variations, thus enhancing the reliability and efficiency of spacecraft thermal control systems.
Implementation Method 1
temperature-sensitive shape memory materials that change shape and emissivity properties in response to temperature changes
Implementation Method 2
heat rejection system... altering the effective view factor and emissivity of the radiator surfaces
Data Source
AI summary
A heat rejection system that employs temperature sensitive shape memory materials to control the heat rejection capacity of a vehicle to maintain a safe vehicle temperature. The technology provides for a wide range of heat rejection rates by actuation of the orientation or position of a heat rejection panel which impacts effective properties of the heat rejection system in response to temperature. When employed as a radiator for crewed spacecraft thermal control this permits the use of higher freezing point, non-toxic thermal working fluids in single-loop thermal control systems for crewed vehicles in space and other extraterrestrial environments.