Phase Change Material Thermal Control for Cold Chain
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Solution Overview
Problem
Current cold chain transportation methods for maintaining temperatures below −18° C. are inefficient, costly, and environmentally harmful, particularly for niche products like vaccines, due to the lack of effective passive shippers that can sustain such low temperatures for extended periods without relying on dry ice.
Innovation Solution
A thermal control system utilizing a combination of inorganic and organic phase change materials (PCMs) with varying formulations, including salts and hydrocarbons, to maintain temperatures between −15° C. and −40° C. for up to 12 hours without the need for active electronic control or dry ice, using a dual-layer structure for enhanced cooling efficiency and thermal insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If dry ice is used for maintaining temperatures below −18° C., then the temperature requirement is met, but the system becomes inefficient, non-recyclable, and increases carbon tax emissions
Solution Approach 1:
The patent utilizes phase change materials (PCMs) that undergo phase transitions between solid and liquid states to maintain temperatures below −18° C. The PCMs are pre-cooled to the desired temperature and enclosed in reusable containers, eliminating the need for dry ice sublimation and its associated energy losses and environmental harm.
Solution Approach 2:
The invention changes the physical state parameter of the cooling medium from gaseous dry ice to solid/liquid PCM formulations. By adjusting the composition and phase change temperature of the PCM, the system achieves efficient temperature maintenance below −18° C. without the inefficiencies of dry ice sublimation.
2Measurement precision
If active shippers with electronically powered thermostats are used for accurate temperature control, then temperature accuracy is improved, but the system becomes bulky, costly, and not easily transported
Solution Approach 1:
The passive shipper system uses phase change materials that automatically regulate temperature through their inherent phase transition properties, eliminating the need for external power sources, thermostats, and electronic control systems. The PCM self-regulates temperature at its phase change point, providing accurate temperature control without bulkiness or high cost.
Solution Approach 2:
The patent replaces active electronic temperature control systems with a passive thermal regulation system based on phase change physics. The PCM containers provide temperature control through physical phase transitions rather than electronic thermostats, making the system lighter, cheaper, and more transportable.
3Device complexity
If conventional passive shippers are used for temperatures below −18° C., then simplicity is maintained, but the working duration is limited to several hours
Solution Approach 1:
The invention employs composite PCM formulations combining multiple substances with different phase change temperatures and latent heats. This composite approach extends the working duration by providing a broader temperature maintenance window and higher energy storage capacity, while maintaining the simplicity of passive shipper design.
Solution Approach 2:
The PCM-based passive shipper system serves multiple functions: temperature maintenance, extended duration, and reusability. The same basic passive shipper design can maintain temperatures below −18° C. for extended periods by simply changing the PCM formulation, providing multi-functionality without increasing system complexity.
4Temperature
If dry ice packing is used for maintaining low temperatures, then temperature control is achieved, but the system becomes non-recyclable and environmentally harmful
Solution Approach 1:
The PCM containers are designed to be reusable and recyclable, eliminating the need to discard dry ice packs after single use. The PCM can be re-cooled and reused multiple times, reducing carbon emissions and environmental harm associated with continuous production of single-use cooling materials.
Solution Approach 2:
The invention converts the harmful effect of dry ice sublimation (which releases CO2) into a beneficial reusable PCM system. The PCM phase change process maintains temperature without gas emission, transforming the environmental harm of traditional dry ice packing into an environmentally friendly solution.
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 a cost-effective, reusable, and environmentally friendly solution for maintaining extremely low temperatures, enhancing cooling efficiency and duration, and reducing carbon emissions, making it suitable for pharmaceutical and food transportation.
Implementation Method 1
A thermal control system utilizing a combination of inorganic and organic phase change materials (PCMs) with varying formulations, including salts and hydrocarbons, to maintain temperatures between −15° C. and −40° C. for up to 12 hours
Implementation Method 2
using a dual-layer structure for enhanced cooling efficiency and thermal insulation
Data Source
AI summary
A thermal control system with new phase change material (PCM) formulations that are able to maintain the system interior in a temperature range of, for example, −15 to −40° C., for a tunable working period from several hours to approximately half a day, is provided. The composition includes the inorganic and organic materials. The inorganic materials include the inorganic salts and various functional additives; while the organic materials include fatty acids, hydrocarbons and various nanostructures.