Phase Change Insulation Reset Using Cool Air in Warm Climates
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Solution Overview
Problem
Conventional thermal insulation systems with phase change materials (PCMs) are ineffective in warm climates where ambient temperatures remain above the PCM's transition temperature for extended periods, causing PCMs to remain in a liquid state and reducing their ability to store and emit heat effectively.
Innovation Solution
A system that utilizes a cool air source to lower the temperature of PCMs to their solid state by directing cool air proximate to the PCM, either manually or automatically, using various configurations such as channels in insulation layers or ducts, to manage temperature fluctuations and reduce energy loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PCMs are used in warm climates where ambient temperatures remain above the transition temperature, then the PCMs remain in liquid state and cannot effectively store and emit heat, but adding active cooling components increases system complexity
Solution Approach 1:
The system uses existing HVAC cool air to solidify the PCM, allowing the PCM to reset itself during nighttime or off-peak hours without requiring separate active cooling mechanisms. This self-service approach maintains reliability while avoiding additional complexity
Solution Approach 2:
The existing HVAC system serves dual purposes: providing cooling to the building and simultaneously resetting the PCM by directing cool air through the insulation layers. This multi-functionality eliminates the need for dedicated PCM cooling equipment, reducing system complexity while maintaining effectiveness
2Reliability
If conventional insulation alone is used, then the system is simple, but it cannot maintain consistent heat flow during rapid external temperature fluctuations
Solution Approach 1:
The system combines conventional insulation with PCM layers to create a composite thermal management system. The conventional insulation provides baseline thermal resistance while the PCM adds thermal mass and heat flow regulation capabilities, achieving consistent heat flow during temperature fluctuations
Solution Approach 2:
The system dynamically changes the thermal parameters of the insulation assembly by controlling the phase state of the PCM. During nighttime or off-peak hours, cool air solidifies the PCM, increasing its heat storage capacity. During daytime, the PCM melts and releases heat, maintaining consistent heat flow through the building envelope
3Productivity
If PCMs are used without active cooling, then the system is simpler, but the PCMs remain liquefied for extended periods and are ineffective until ambient temperature drops
Solution Approach 1:
The system performs preliminary cooling of the PCM during nighttime or off-peak hours when ambient temperatures are lower or energy costs are reduced. This preliminary action solidifies the PCM in advance, preparing it to effectively store and release heat during the next daytime heating period, thereby maintaining reliability while improving overall energy efficiency
Solution Approach 2:
The system implements periodic cooling cycles where the HVAC system directs cool air through the insulation layers at specific intervals (typically nighttime or off-peak hours) to solidify the PCM. This periodic action ensures the PCM remains functional while optimizing energy usage patterns, improving productivity without sacrificing reliability
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 the efficiency of heating and cooling systems by maintaining a consistent heat flow, reducing energy output, and minimizing temperature variations, thereby optimizing energy usage and reducing peak energy loads.
Implementation Method 1
PCMs are solid at room temperature but as the temperature increases the PCMs liquefy and absorb and store heat
Implementation Method 2
the PCMs liquefy and absorb and store heat
Implementation Method 3
when the temperature decreases, the PCMs solidify and emit heat
Implementation Method 4
the PCMs solidify and emit heat
Implementation Method 5
a cool air source operable to cool air below a transition temperature of the phase change material; and means for controlling the cool air source such that cool air can be directed from the cool air source to an area proximate the phase change material
Data Source
AI summary
An active thermal insulation system is disclosed. The system utilizes a cool air source in conjunction with a phase change material and/or conventional insulation. In a controlled manner, the cool air source facilitates the transition of the phase change material from a substantially liquid state to a substantially solid state allowing the solid phase change material to absorb heat. Cool air may be directed to the phase change material via a duct, plenum or other suitable passageway capable of introducing the cool air to the phase change material. A system outlet allows heat created during the phase change material's transition from a liquid state to a solid state to be exhausted to the atmosphere or elsewhere. The system is ideal for desert and other warm weather climates.