[tommy_greens]

Looking for an easy way to get cryogenic temperatures during extraction, dewaxing, solvent recovery etc.
I've learned that they are being used by precision on their flagship PX2 or PX1 model.
There are some complaints on their thread though about the power of the chiller that comes with it.

Does any one have a model or a supplier for good quality cryo chillers that gets to -40C and keep up with a heavy load? It would be a dream to find a unit with the power chill multiple locations at the same time and have an adjustable thermostat.

There is a company in India that fabricates them to ones desired specifications but I'm concerned about potential breakdowns and the availability of parts and people that can install them.

https://www.chillersindia.in/cryo-chiller.php

[snake11]

I have used thermo scientific and Neslab chillers(not cryo) and never had complaints. I'm sure they have cryo models. I'd stick to a name brand company that you can get parts and service from.

[Permacultuure]

Poly science

[Permacultuure]

Poly science

[snake11]

Originally Posted by Permacultuure

Poly science

I've used poly science as well and never had problems.

[Gray Wolf]

The latent heat of vaporization for n-Butane is 165.6 btu/lb, so that converts to about 48.5 Watts per pound:

https://www.engineeringtoolbox.com/butane-d_1415.html
https://www.rapidtables.com/convert/p...TU_to_Watt.htm

You have to remove both any heat added by the pump, as well as the heat of vaporization to return it to liquid state at about 31.2F.

You can measure the temperature of the gas exiting your pump closely enough for our purposes, measuring the plumbing fitting at the pump discharge with a hand held infrared thermometer.

If you subtract 31.2 from that reading, you will have your delta T for your calculations.

The specific heat of n-Butane is 0.39 btu/lb/F, and can be found in the engineering toolbox link above.

It says that it takes 0.39 btu’s per pound of butane, to raise its temperature 1 degree F.

So if you pump exhaust is 120F, your delta T is 120F – 31.2F= 88 degrees delta T.

Soooo, 1 lb of n-Butane at 88 degrees delta T, requires 88/0.39=225.6 btu to return it to 31.2F.

225.6 btu + 165.6 btu heat of Vaporization = 279.88 btu/lb to remove to return it to liquid state.

Using the converter above, that is about 82W per pound.

We are building our own 10,000 btu/3000W -40C chiller, using a refrigeration plant designed for a -40C walk in cooler, and have the refrigeration plant, the stainless barrel and the stainless chiller coil, but still looking for a circulation pump capable of running at -40C reliably.

So far the magnetic drive pumps that I’ve found are ghastly expensive, so I’ve designed my own air driven one as a last resort. Any of ya’ll know of a good -40C pump that doesn’t cost one arm, leg, and testicle?

As one more thought, check out the properties of a 50/50 mix of Methanol and water. It doesn’t develop the same viscosity issues that glycol develops at subzero temperatures, and actually has good thermal properties.

[NorPene Solutions]

Could a 50/50 mix of Methanol and water be placed in a chest freezer or would that pose too high of a safety issue.

[A6 Grower]

Originally Posted by mrsmarybrown

Could a 50/50 mix of Methanol and water be placed in a chest freezer or would that pose too high of a safety issue.

I have a chest freezer filled with 50/50 glycol and water. Its been working ok. Recently i tossed a few cheapo harbor freight fountain pumps in there to move the glycol around as it was freezing around the edges and top but liquid in the center. Now the whole thing is a nice orange slushy mixture that holds the -10f my freezer gets it to much much longer. Even with a hot lab at 80f my glycol is only at 0f at the end of my 10 hour days. Poor freezer works 24/6 probably. the sides get a little warm to the touch, i'm wondering how long she'll last.

Was pleasantly surprised the little mag driven fountain pumps were able to work as well as they do.

[tommy_greens]

Originally Posted by Permacultuure

Poly science

Dont see a poly sci model that goes to -40.
Have you used one of their chillers successfully to reach cryo temps?

[tommy_greens]

Originally Posted by Gray Wolf

The latent heat of vaporization for n-Butane is 165.6 btu/lb, so that converts to about 48.5 Watts per pound:

https://www.engineeringtoolbox.com/butane-d_1415.html
https://www.rapidtables.com/convert/p...TU_to_Watt.htm

You have to remove both any heat added by the pump, as well as the heat of vaporization to return it to liquid state at about 31.2F.

You can measure the temperature of the gas exiting your pump closely enough for our purposes, measuring the plumbing fitting at the pump discharge with a hand held infrared thermometer.

If you subtract 31.2 from that reading, you will have your delta T for your calculations.

The specific heat of n-Butane is 0.39 btu/lb/F, and can be found in the engineering toolbox link above.

It says that it takes 0.39 btu’s per pound of butane, to raise its temperature 1 degree F.

So if you pump exhaust is 120F, your delta T is 120F – 31.2F= 88 degrees delta T.

Soooo, 1 lb of n-Butane at 88 degrees delta T, requires 88/0.39=225.6 btu to return it to 31.2F.

225.6 btu + 165.6 btu heat of Vaporization = 279.88 btu/lb to remove to return it to liquid state.

Using the converter above, that is about 82W per pound.

We are building our own 10,000 btu/3000W -40C chiller, using a refrigeration plant designed for a -40C walk in cooler, and have the refrigeration plant, the stainless barrel and the stainless chiller coil, but still looking for a circulation pump capable of running at -40C reliably.

So far the magnetic drive pumps that I’ve found are ghastly expensive, so I’ve designed my own air driven one as a last resort. Any of ya’ll know of a good -40C pump that doesn’t cost one arm, leg, and testicle?

As one more thought, check out the properties of a 50/50 mix of Methanol and water. It doesn’t develop the same viscosity issues that glycol develops at subzero temperatures, and actually has good thermal properties.

That is some pretty complex math! If I really dove in i could probably get a pretty accurate idea of the heat load I want to cool though. Thanks for the break down GW!
Would you ever consider buying a unit like this if you were in the market for something off the shelf instead of DIY?
https://farrarscientific.com/index.php?pg=21

[Gray Wolf]

Originally Posted by tommy_greens

That is some pretty complex math! If I really dove in i could probably get a pretty accurate idea of the heat load I want to cool though. Thanks for the break down GW!
Would you ever consider buying a unit like this if you were in the market for something off the shelf instead of DIY?
https://farrarscientific.com/index.php?pg=21

I would sure consider it at the right price.