Is it possible to build some sort of insulator so that anything put in it retains its initial temperature for extremely long periods of time. Not minutes or hours, but weeks, months or even longer. I’ve seen the containers at doctors surgeries that have liquid nitrogen in them and read that they can store it up to a few weeks, they can store it longer than this but it appears to suffer around a 2% loss per day.

Cymek said:

Is it possible to build some sort of insulator so that anything put in it retains its initial temperature for extremely long periods of time. Not minutes or hours, but weeks, months or even longer. I’ve seen the containers at doctors surgeries that have liquid nitrogen in them and read that they can store it up to a few weeks, they can store it longer than this but it appears to suffer around a 2% loss per day.

Refrigerators and freezers are designed for this sort of thing.

Define ‘near perfect’; that is what level of loss would you consider to be acceptable?

Bubblecar said:

Cymek said:

Is it possible to build some sort of insulator so that anything put in it retains its initial temperature for extremely long periods of time. Not minutes or hours, but weeks, months or even longer. I’ve seen the containers at doctors surgeries that have liquid nitrogen in them and read that they can store it up to a few weeks, they can store it longer than this but it appears to suffer around a 2% loss per day.

Refrigerators and freezers are designed for this sort of thing.

…but laws of thermodynamics require them to have an energy input.

diddly-squat said:

Define ‘near perfect’; that is what level of loss would you consider to be acceptable?

I was thinking that if you wanted to maintain something at a constant temperature without external energy input for months or years and the loss would need to be so low that what you are storing doesn’t become corrupted. I’d assume it would be entirely dependant on the substance in question, but lets say it was liquid nitrogen could you build a vessel to store it for many years (far longer than what currently exists) and still have a usable quantity left. Is this something we could do now but its not really necessary as the process is costly and difficult and no real need exists.

> I’d assume it would be entirely dependant on the substance in question

And its temperature relative to ambient temperature. And the laws of thermodynamics.

Bubblecar said:

> I’d assume it would be entirely dependant on the substance in question

And its temperature relative to ambient temperature. And the laws of thermodynamics.

So one size fits all container isn’t really possible

diddly-squat said:

Define ‘near perfect’; that is what level of loss would you consider to be acceptable?

Near infinite resistance to thermal transmission is what is required I imagine.

The Rev Dodgson said:

diddly-squat said:

Define ‘near perfect’; that is what level of loss would you consider to be acceptable?

Near infinite resistance to thermal transmission is what is required I imagine.

Thats a good way of putting it.

Yes

I once asked in SSSF: if you took a brand new desktop PC in perfect working order, and left it (unplugged) in a well-insulated tomb indefinitely, how long it would take for it to no longer function.

Can’t remember the answer.

Bubblecar said:

I once asked in SSSF: if you took a brand new desktop PC in perfect working order, and left it (unplugged) in a well-insulated tomb indefinitely, how long it would take for it to no longer function.

Can’t remember the answer.

A few years?

Stuff dries out…

Rule 303 said:

Bubblecar said:

I once asked in SSSF: if you took a brand new desktop PC in perfect working order, and left it (unplugged) in a well-insulated tomb indefinitely, how long it would take for it to no longer function.

Can’t remember the answer.

A few years?

Stuff dries out…

I mean well insulated with the right temperature and humidity to preserve it for as long as possible.

Bubblecar said:

Rule 303 said:

Bubblecar said:

I once asked in SSSF: if you took a brand new desktop PC in perfect working order, and left it (unplugged) in a well-insulated tomb indefinitely, how long it would take for it to no longer function.

Can’t remember the answer.

A few years?

Stuff dries out…

I mean well insulated with the right temperature and humidity to preserve it for as long as possible.

the windows updates would take forever when it got booted up…

The Rev Dodgson said:

diddly-squat said:

Define ‘near perfect’; that is what level of loss would you consider to be acceptable?

Near infinite resistance to thermal transmission is what is required I imagine.

I said near perfect as I imagine a perfect insulator isn’t possible, you always have a loss even if its almost infinitesimal

Cymek said:

diddly-squat said:

Define ‘near perfect’; that is what level of loss would you consider to be acceptable?

I was thinking that if you wanted to maintain something at a constant temperature without external energy input for months or years and the loss would need to be so low that what you are storing doesn’t become corrupted. I’d assume it would be entirely dependant on the substance in question, but lets say it was liquid nitrogen could you build a vessel to store it for many years (far longer than what currently exists) and still have a usable quantity left. Is this something we could do now but its not really necessary as the process is costly and difficult and no real need exists.

That would not be possible without out input of external energy – and to note, the process is independent of what substance you are trying to keep cool (or hot).

The Rev Dodgson said:

diddly-squat said:

Define ‘near perfect’; that is what level of loss would you consider to be acceptable?

Near infinite resistance to thermal transmission is what is required I imagine.

yes, well I was trying to avoid that particular conundrum

The OP requires an insulator that will insulate for weeks, months, or even longer.

For any specification, we can design an appropriate insulator using conventional materials.

The resulting object might be very large…

Thought you were going to ask for a perfect electrical insulator, that’s more difficult.

I’ve already designed a couple or three of near-perfect thermal insulators.

The third best was moondust in vacuum. The dust is intrinsically non-conductive and being angular the contact points between dust grains are small.

The second best was a tungsten aerogel, again in vacuum, that I planned to use to insulate a spacecraft against the heat of the solar corona.

The best was a three-layer structure of using titanium/carbon molybdenum and aluminium, with carefully controlled reflectivity and absorptivity that would insulate a subzero temperature against head from molten uranium.

Cymek said:

Is it possible to build some sort of insulator so that anything put in it retains its initial temperature for extremely long periods of time. Not minutes or hours, but weeks, months or even longer. I’ve seen the containers at doctors surgeries that have liquid nitrogen in them and read that they can store it up to a few weeks, they can store it longer than this but it appears to suffer around a 2% loss per day.

Have you seen the thermodynamic equations here https://en.wikipedia.org/wiki/Vacuum_flask#Thermodynamics for the rate of heat transfer from a vacuum flask?

These equations are for a single vacuum between inner and outer layers. By changing one vacuum gap between two layers to two vacuum gaps between three layers the heat transfer rate drops enormously, by a factor of 16 if I’ve calculated it correctly. With more vacuum gaps we have progressively better insulation. Say initially a 2% loss per day, would be roughly a 30% loss in two weeks. Cut that by 16 gives about a 30% loss in 8 months. Cut the energy loss by more and it will last longer.

aerogel

wookiemeister said:

aerogel

Yes, that was my second option.

There are aerogels and aerogels, they’re not all of equal quality – for example the Eiffel Tower qualifies as an aerogel based on mass and volume, but it isn’t a very good insulator.