Heat transfer system with phase change composition
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Solution Overview
Problem
Existing heat transfer systems utilizing phase change materials (PCMs) face limitations in efficiency due to thermal barriers, complexity, and stability issues in PCM slurries, as well as limited temperature ranges, which hinder effective heat transfer across a wide range of temperatures.
Innovation Solution
A heat transfer system employing a phase change composition comprising two PCMs with different melting points, where one PCM is in a solid state for heat absorption and the other in a liquid state for heat rejection, allowing for efficient heat transfer through latent heat of fusion, and eliminating the need for emulsifying agents by using plant or animal oils with compatible thermal properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PCM slurries are used to enable heat transfer fluid flow, then heat transfer rate is improved, but thermal conductivity is reduced due to microcapsule walls acting as insulators
Solution Approach 1:
The invention extracts the PCM from microcapsule structures and uses pure PCM materials instead. By eliminating the microcapsule walls that act as thermal insulators, the system achieves higher thermal conductivity while maintaining the heat transfer rate improvement through direct PCM circulation.
Solution Approach 2:
The invention uses composite PCM formulations combining multiple PCM materials with different melting points to create a slurry that maintains stability and effectiveness across a broader temperature range, addressing both heat transfer rate and thermal conductivity requirements.
2Stability of the object's composition
If microcapsules are used to contain PCM material, then phase change stability is improved, but system complexity and manufacturing cost increase
Solution Approach 1:
The invention removes the microcapsule containment structure entirely and uses bulk PCM materials instead. This extraction eliminates the complex microcapsule fabrication process and associated costs while maintaining phase change stability through proper PCM selection and formulation.
Solution Approach 2:
The invention changes the physical state parameters of PCM materials by selecting specific plant, animal, or paraffinic oils with appropriate melting points. This parameter-based approach provides stability without requiring microcapsule structures, simplifying the system while maintaining compositional stability during phase changes.
3Device complexity
If single PCM material is used, then system simplicity is maintained, but temperature range effectiveness is limited
Solution Approach 1:
The invention employs composite PCM formulations combining multiple PCM materials (plant oils, animal oils, or paraffinic oils) with different melting points. This composite approach extends the effective temperature range while maintaining relative system simplicity by using direct PCM circulation without complex microcapsule or emulsion structures.
Solution Approach 2:
The invention segments the temperature range by using multiple PCM materials, each effective at different temperature ranges. By combining these segmented PCM materials, the system achieves broad temperature range effectiveness while maintaining simplicity through direct PCM use rather than complex encapsulated structures.
4Use of energy by moving object
If PCM transitions from liquid to solid at the interface, then phase change heat transfer occurs, but thermal barrier is formed reducing heat transfer efficiency
Solution Approach 1:
The invention uses dynamic PCM circulation where the PCM is continuously pumped through the heat transfer system. This dynamic approach prevents solid PCM from forming stable thermal barriers at interfaces, as the continuous flow maintains heat transfer efficiency while still utilizing latent heat during phase changes.
Solution Approach 2:
The invention selects PCM materials with specific thermal properties and controls operating parameters to manage phase change behavior. By carefully selecting plant, animal, or paraffinic oils with appropriate melting points and thermal conductivities, the system optimizes heat transfer efficiency while minimizing thermal barrier formation during liquid-solid transitions.
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 approach enhances heat transfer efficiency by optimizing thermal conductivity and stability, enabling effective heat management across a broader temperature range without the complexity and cost associated with traditional PCM slurries.
Implementation Method 1
transfers heat from the phase change composition through the latent heat of fusion of the second PCM
Implementation Method 2
phase change composition comprising a first PCM that is a plant or animal or paraffinic oil having a first melting point or solidification temperature and a second PCM that is a plant or animal or paraffinic oil having a second melting point or solidification temperature
Data Source
AI summary
A heat transfer system is disclosed that includes a heat exchanger comprising an inlet, an outlet, and a flow path through the heat exchanger between the inlet and the outlet. The system also includes a fluid circulation loop external to the heat exchanger connecting the outlet to the inlet. A phase change composition is disposed in the system flowing through the fluid circulation loop and the flow path through the heat exchanger. This the phase change composition includes a first PCM that is a plant or animal or paraffinic oil having a first melting point and a second PCM that is a plant or animal or paraffinic oil having a second melting point lower than the first melting point.