Why is 100% efficient thermal insulator impossible?

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SUMMARY

The discussion centers on the impossibility of achieving a 100% efficient thermal insulator. While a vacuum can effectively stop conduction and convection, it does not eliminate thermal radiation, which is a critical factor in heat transfer. The conversation highlights that a perfect insulator would require a perfect mirror capable of reflecting all frequencies of radiation, which is unattainable with current technology. Therefore, while near-perfect insulation is possible, complete thermal insulation remains an impossibility due to the inherent properties of heat transfer.

PREREQUISITES
  • Understanding of the three types of heat transfer: conduction, convection, and radiation.
  • Familiarity with the concept of a vacuum and its limitations in thermal insulation.
  • Knowledge of thermal conductivity and its measurement.
  • Basic principles of thermodynamics, particularly the concept of entropy.
NEXT STEPS
  • Research the properties and limitations of thermal insulation materials, including aerogels and vacuum insulation panels.
  • Explore advanced concepts in thermodynamics, focusing on entropy and its implications for energy transfer.
  • Investigate the design and functionality of perfect mirrors and their reflectance across different radiation frequencies.
  • Learn about experimental methods for creating and measuring vacuum conditions in thermal applications.
USEFUL FOR

Physicists, engineers, and materials scientists interested in thermal management, insulation technologies, and the fundamental principles of heat transfer.

linux kid
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Somebody told me this and I have yet to figure out even if the statement is true or not.
 
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Because if it could be done, you could stop entropy. Which you can't.

Even if you could stop conduction of heat, how would you stop a body from radiating heat?
 
If u can stop entropy its lik saying u cud stop time.SO i guess its not possible
 
anantchowdhary said:
If u can stop entropy its lik saying u cud stop time.SO i guess its not possible

Translation: If you can stop entropy it's like saying you could stop time, so I guess it's not possible.
 
Stop entropy? What does that mean?
linux kid said:
Why is 100% efficient thermal insulator impossible?

Somebody told me this and I have yet to figure out even if the statement is true or not.
If the question was, is there such a thing as a perfect insulator (i.e., has zero thermal conductivity), then the answer is "yes, a vacuum". Of course, you can't make a true vacuum, nor does a vacuum prevent radiation.
 
I like to look at such questions backwards: how could you make a perfect insulator? There are 3 types of heat transfer: conduction, convection, and radiation...

As Gokul said, a vacuum will stop conduction and convection completely, but we can't make a perfect vacuum and even if you could, you'd have to support the structure with something. So you can't completely eliminate either conduction or convection in a device (though you can eliminate conduction between objects that aren't touching. But you can get either well above 99%.

Stopping radiation is much more difficult than stopping either conduction or convection because it requires a perfect mirror that is perfect at all frequencies of radiation. And though you can get mirrors at in exess of 99% reflectance, the frequency range is limited.
 
Gokul43201 said:
then the answer is "yes, a vacuum". Of course, you can't make a true vacuum, nor does a vacuum prevent radiation.

Since a vacuum doesn't prevent radiation, how does that make it a perfect insulator?
 
It doesn't because it does not prevent readiation as gokul said.

But this perfect vacuum must exist a place farther away than light has reached since bing bang? Because if no radiation or mass have reached the point, nothing can be there.
 

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