Phase-Change Thermal Sink Cartridge for Stable 0-4°C Cooling
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Solution Overview
Problem
Existing phase-change containers for thermal regulation face challenges in maintaining a steady temperature near the phase-change temperature due to insulating properties that restrict thermal energy transfer and allow for temperature fluctuations, especially when used for temperature-sensitive materials like biological samples that require a narrow temperature range between 0° Celsius and 4° Celsius.
Innovation Solution
A thermal sink cooling cartridge with an expandable base container filled with an aqueous medium and a thermoconductive cover that maintains constant contact with the solid phase of the medium, allowing for efficient heat transfer and accommodating expansion without rupture, using materials like polyethylene and thermoconductive alloys to ensure effective cooling and temperature stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If plastic or rubber container materials are used to enclose phase change material, then container flexibility and durability are improved, but thermal conductivity deteriorates causing temperature instability
Solution Approach 1:
The container is divided into two distinct parts: an inner flexible bladder made of plastic or rubber for holding the phase change material, and an outer rigid shell made of thermally conductive material for thermal regulation. This segmentation allows each component to perform its specialized function without compromise.
Solution Approach 2:
The container employs a composite structure combining flexible polymer materials (for the bladder) with rigid thermally conductive materials (for the outer shell). This composite approach integrates the advantages of both material types: flexibility and containment from the polymer, and thermal conductivity from the rigid shell.
2Quantity of substance
If absorptive materials like gels or foams are used to contain water, then weight and cost are reduced, but thermal conductivity deteriorates restricting heat flow
Solution Approach 1:
The system separates the water containment function (performed by the flexible bladder) from the heat transfer function (performed by the rigid thermally conductive shell). This segmentation eliminates the need for absorptive materials that compromise thermal conductivity.
Solution Approach 2:
The flexible bladder acts as an intermediary containing the water, while the rigid thermally conductive shell serves as the primary heat transfer medium. This intermediary arrangement allows water to be contained without requiring it to directly facilitate heat transfer.
3Reliability
If insulation barriers are placed between phase change material and the object to be cooled, then thermal energy transfer is restricted, but temperature control precision deteriorates
Solution Approach 1:
The container structure segments the thermal protection function (provided by the flexible bladder containing the phase change material) from the temperature control function (provided by the rigid thermally conductive shell in direct contact with the cooled object). This ensures precise temperature control while maintaining thermal protection.
Solution Approach 2:
Different parts of the container have different thermal properties: the inner bladder provides thermal protection through phase change, while the outer shell provides high thermal conductivity for precise temperature control at the contact surface with the cooled object.
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 provides a passive thermal sink that maintains objects at a consistent temperature near the phase-change medium's transition temperature, effectively cooling and preserving temperature-sensitive materials by ensuring direct contact between the solid phase and the thermoconductive cover, thus preventing temperature fluctuations and maintaining stability within the desired range.
Implementation Method 1
The latent heat absorption property of material phase change has been used as a means for absorbing heat influx and maintaining the temperature of objects in close contact or local proximity within a desired range. The phase change of water, due to the relatively large latent heat of fusion of the material, provides an excellent means of maintaining temperatures near 0° Celsius.
Implementation Method 2
a thermoconductive cover, wherein an aqueous medium is stored in the base container and in contact with the thermoconductive cover
Data Source
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AI summary
Cartridges for maintaining objects at a desired temperature for extended periods of time can be constructed by sealing a thermoconductive cover on a flexible base container filled with a phase change material with a phase change temperature identical to the desired temperature.