Aging behavior of polymeric-fiber based vacuum insulation panels

Area of Science:

• Materials Science
• Thermal Engineering
• Nanotechnology

Background:

• Vacuum insulation panels (VIPs) are crucial for energy efficiency in appliances and buildings.
• Achieving both initial and long-term insulation performance in VIPs is challenging due to conflicting dependencies on core material porosity.
• Aging resistance is critical for the reliability of VIPs.

Purpose of the Study:

• To develop a novel VIP using ultrathin polymeric fibers as core material.
• To investigate the initial thermal conductivity and aging behavior of the new VIP.
• To assess the potential of polymer fiber-based VIPs as a sustainable alternative.

Main Methods:

• Fabrication of VIPs with ultrathin polymeric fibers (7 μm diameter).
• Measurement of thermal conductivity and pressure in situ.
• Analysis of short-term and long-term aging characteristics.

Main Results:

• Achieved low initial thermal conductivity of 1.6 mW mK^-1 at 85% porosity.
• Observed two-phase aging: short-term (viscoelastic, partially reversible) and long-term (gas permeation).
• Demonstrated a low long-term aging rate of ~0.1 mW per mK per year.

Conclusions:

• Polymer fiber-based VIPs offer a superior combination of low initial conductivity and strong aging resistance.
• The developed VIPs present a cleaner alternative to conventional core materials.
• Further research into polymer fiber-based VIPs is warranted.