Phase Change Heat Exchanger for Simultaneous Thermal Buffering
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Solution Overview
Problem
Existing heating and cooling systems for directed energy weapons are heavy, lack operational flexibility, and cannot simultaneously charge and discharge, making them inefficient for intermittent high-demand bursts while requiring continuous recharging.
Innovation Solution
A thermal buffer system using a phase change heat exchanger (PCHEX) with separate conduits for coolant and refrigerant fluids, allowing simultaneous charging and discharging, and utilizing a thermally conductive matrix with phase change material to manage heat transfer efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional refrigeration systems or single PCHEX units are used, then cooling capacity is provided, but system weight is high and operational flexibility is limited
Solution Approach 1:
The system divides the PCHEX into multiple independent channels (first channel for coolant, second channel for refrigerant) that can operate simultaneously and independently. This segmentation allows the cooling system to provide both continuous background cooling and intermittent high-demand cooling bursts without requiring separate systems, thereby reducing overall weight while improving operational flexibility.
Solution Approach 2:
The single PCHEX unit performs multiple functions by handling both coolant cooling and refrigerant cooling simultaneously through separate channels. The first channel provides continuous cooling to the coolant, while the second channel enables intermittent charging of the PCM for high-demand cooling bursts. This multi-functionality eliminates the need for separate refrigeration systems, reducing weight while enhancing adaptability.
2Adaptability or versatility
If the same conduits are used for both charging and discharging PCHEX, then device complexity is reduced, but operational flexibility is lost and fluid selection is restricted
Solution Approach 1:
The PCHEX is segmented into distinct first conduits for coolant flow and second conduits for refrigerant flow. This segmentation allows independent optimization of fluid pathways, enabling different fluids to be used for cooling versus charging operations without interference, thereby restoring operational flexibility while maintaining manageable system complexity through structured organization.
Solution Approach 2:
Different regions of the PCHEX are assigned different functions: the first conduits are dedicated to coolant circulation for continuous cooling, while the second conduits are dedicated to refrigerant circulation for PCM charging. This local specialization allows each fluid pathway to be optimized for its specific purpose, improving operational flexibility without requiring complete system redesign.
3Reliability
If PCM is cooled offline using external refrigeration, then cooling capacity is restored, but system response time is increased and continuous readiness is lost
Solution Approach 1:
The system enables continuous useful action by allowing the coolant channel to operate continuously for background cooling while the refrigerant channel simultaneously charges the PCM for future high-demand bursts. This parallel operation eliminates idle recharging time and maintains continuous system readiness, as both cooling functions are active simultaneously rather than sequentially.
Solution Approach 2:
The refrigerant channel performs preliminary action by continuously charging the PCM with cooling capacity even when the coolant channel is operating. This preliminary charging ensures that when high-demand cooling bursts are required, the PCM is already prepared and can immediately provide the needed cooling capacity without delay, thereby reducing response time and maintaining continuous readiness.
4Reliability
If water is used as coolant for laser diodes, then cooling effectiveness is improved, but compatibility with ice formation cooling is lost
Solution Approach 1:
The system segments the fluid pathways into separate first conduits for coolant (water) and second conduits for refrigerant (glycol solution). This segmentation allows water to be used as the coolant for laser diodes where it provides optimal cooling effectiveness, while simultaneously allowing glycol solution to be used as the refrigerant for PCM charging where it must remain liquid below freezing points. The separation eliminates fluid compatibility conflicts while maintaining both cooling functions.
Solution Approach 2:
Different fluid types are assigned to different local regions of the system based on their optimal performance characteristics. Water is used in the first conduits where high cooling effectiveness is needed for laser diodes, while glycol solution is used in the second conduits where low-temperature operation is required for PCM charging. This local quality assignment optimizes both functions simultaneously without requiring fluid interchangeability.
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 system provides efficient, lower-weight, higher-capacity cooling that can operate in intermittent bursts while being recharged continuously, reducing overall system weight and power consumption, and enhancing operational flexibility.
Implementation Method 1
heat is transferred from the fluid to the PCM, thereby cooling the fluid and causing the PCM to melt, i.e., to change phase
Implementation Method 2
The PCM is melted, i.e., to change phase, at a relatively constant temperature
Implementation Method 3
a thermally conductive matrix with phase change material (PCM) for efficient heat transfer and storage
Implementation Method 4
heat is transferred between the second fluid and the PCM in a fourth direction opposite to the second direction and results in a second phase change in the PCM opposite to the first phase change therein
Data Source
AI summary
A thermal buffer for an intermittent thermal load, e.g., a directed energy weapon (DEW) system, includes a phase change heat exchanger (PCHEX), an apparatus for circulating a first working fluid of the thermal load through first conduits of the PCHEX cell in a first direction such that heat is transferred between the first fluid and a phase change material (PCM) of the PCHEX in a second direction and causes a first phase change in the PCM, and an apparatus for circulating a second working fluid of, e.g., a heat pump through second conduits of the PCHEX in a third direction opposite to the first direction such that heat is transferred between the second fluid and the PCM in a fourth direction opposite to the second direction and results in a second phase change in the PCM opposite to the first phase change therein.