How cold

[phone man]

Hi all. so first off i would just make it clear that if what i’m asking is possible then i would not be doing the work myself, i will get professional to do it.
I would like to make a small freezer go down to about -150, would making the freezer colder be done by more gas? different compressor or something else altogether?

cheers all 🙂

[kwatt]

Re: How cold

If you mean to get it down to -150?C you’re not *VERY* specialised equipment I’d think as no domestic unit would ever get even anywhere remotely close to that.

Think, maybe , -30?C if you’re lucky with a very good unit.

K.

[phone man]

Re: How cold

I don’t have the 3-5 thousand pounds to spend on the specialised equipment which is why i wanted to see if something could be done here.
R600 gas has a freezing point of -217c so the gas can handle it but what stops it from going colder? is it the amount of gas, the compressor or something else.
for example, if i took the compressor from a large chest freezer and had it fitted to freeze a 1 foot panel would that freeze it lower or is it limited by the compressor? or is it something to do with having a longer capillary tube or maybe smaller evaporator?

[kwatt]

Re: How cold

Quite probably all of the above.

The cabinets for domestic use are designed to get down to a mean temperature of -18?C which is the ideal storage temperature for frozen foodstuffs. In reality they cycle above and below that but only by a few degrees.

The seals are not designed to operate beyond that.

The cabinet internals, evaporator and insulation are all not designed to operate much below that.

No domestic thermostat will operate at those sorts of temperatures and, I’ve never seen a commercial one with that kind of range on it either. I’d bet they cost a pretty penny as well.

The compressors are also the same, commercial use compressors are a whole different ball game. Much meatier with a lot more oomph and a *much* higher price tag.

Gas used in commercial is often R22 or whatever, not R600a you will hardly ever find R600 used in a true commercial unit.

So at a guess, you’ve got no chance of making a domestic unit get even anywhere near -40?C let alone any cooler than that.

I honestly don’t know how you’d take a unit down that low as I’ve never had call to even look that given it’s medical or scientific use and therefore highly specialised indeed. And, as you point out rightly, specialist equipment like that will run to many thousands of pounds as, it’s specialised and often more or less bespoke for the task it’s required for.

What do you need a unit to get down to that for anyway?

K.

[phone man]

Re: How cold

Thanks for breakdown, it was worth a thought.
It’s for phone repairs believe it or not. to remove the broken screen quickly you put it face down on a panel that’s at -150 for 20 – 30 seconds and the screen virtually falls off.

Thanks

[kwatt]

Re: How cold

I’d imagine then it’s whether or not there’s a business case for the cost it’d incur to get something that would do that.

I’d make sure and try it first though before parting with that kinda money. 😉

K.

[captaincaveman1]

Re: How cold

Just a random thought how about a thin piece of metal placed over the phone screen and obviously using the correct safety gloves spraying pipe freeze spray over the metal and see if the screen sticks to that ❓ :tup:

[Author]

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