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Hi guys, I've been working on some cryogenic refrigeration systems and was wondering if anyone would be interested in purchasing such a device.

First off, please note this is a KIT, you will get the main components needed to get going but you will need to do some basic hardware assembly and electrical knowledge to get at least a rudimentary system operational.

You will receive:
Cryogenic refrigeration unit, air cooled with heat reject temperature sensor (thermistor)
Cooling duct
Cooling fan (24vdc)


You will need:
Cryogenic liquid dewar (you can use a vacuum flask like a thermos, they are much much cheaper than lab dewars and work almost as good) [Add 0.5 BTC if you want me to provide one]
Variable autotransformer at least 240VA capacity at 120v [add 1.2 BTC if you want me to provide one]
24vdc power supply for the cooling fan [add 0.2 BTC if you want me to provide one]
Gas separation unit (if you are looking to separate anything from the air)

Potential uses:
Cryogenic liquifaction at atmospheric pressure (this unit can condense nitrogen, oxygen, argon, natural gas and many others at atmospheric pressure)
Superconductor research
Cryogenic sample preservation


Cooling unit specifications:
Cooling capacity at 77 degrees Kelvin: 6 watts with 42 degrees Centigrade heat reject temperature, power consumption of 100W, maximum input power of 120W
Cooling capacity is increased with lower heat reject temperatures.
Air liquifaction at 100W input power: ~1L of liquid air per 24 hours, more or less depending on how well insulated your dewar is

Other notes:
Since this unit can easily condense oxygen, care must be taken to avoid flammable substances since liquid air will contain roughly 20% oxygen
Cryogenic liquids can easily cause severe frostbite if improperly handled. Seller is not responsible for any fires or injuries directly or indirectly related to the sale of this system.
Price includes shipping to the USA only for now, I'll need to check if it's even legal to ship this thing out of the country.

Price: 6.25 BTC
Lead time: 2-4 weeks

Once I generate some more I'll do a quick video and post it here

How many liters of liquid nitrogen can this produce per day?

Could you also provide a dewar? 

Both questions are answered in the OP  ;)

Unless you're talking about an actual lab grade dewar in which case you're at the mercy of ebay pricing.

Wiring diagrams and general instruction are available. Feel free to ask any questions

Sadly, as much as I want this OMFG WANT, my wife has vetoed "more junk." :(

Best of luck.  Had I been able to get one of those in college, I would have been all over it.  My roommate was much more tolerant of cryogenic liquids.  We may have spent an afternoon with a styrofoam cooler full of LN2 at one point after discovering that, A, we could buy it, and B, it was dirt cheap.

Bumping with video :)

I can't seem to find any way to embed it so here's the link
http://www.youtube.com/watch?v=51a7X7lblMc

http://www.geeksofdoom.com/GoD/img/2009/02/2009-02-27-professor_farnsworth.jpg

Good news everyone!

I found a new supplier of these things for much cheaper.

New price is 6.25 BTC + any addons as stated in the original post.

After watching that video, I'm very interested! I spend $30-60 a month on ln2 as is, this could be a sweet way to save money.

I have you confirmed the liquid is nitrogen? It obviously acts like nitrogen, but have you used a probe to check that it is indeed -196C?

Do you have any units that are a bit more self contained? What is the power draw of the unit while running? And finally what was the volume of the container in the video? I'm curious to know how much that made in one day.

I don't have any equipment here capable of verifying that it is indeed nitrogen, but since the only way more gas can enter the jar is if what is already in the jar has condensed. To create a full jug of liquid it would need to be a significant portion nitrogen.

The cooling unit has several watts of cooling capacity at the temperature needed to condense nitrogen so it looks good on paper as well.

I ran the unit at 100W for the video (I think the max is 120W input power)

The jug is about 1-1.5L (not sure exactly, it came from IKEA) if you had a large commercial dewar you should be able to accumulate a significant amount.


It's very self contained as it is, I set it up in the video using just some pieces of scrap wood. A little extra effort and you could make it look nice and pretty. The cooling unit itself is all one piece, the only external parts you need are the variable AC power supply and the cooling fan.

Let me know if you're interested in me sourcing any of those parts for you and I can probably get them for a bit cheaper than the prices listed in the OP based on what I can find for sale.

Cheers

now that's something I can get behind  8)

my company will be using liquid nitrogen for both cooling a 1 KW laser, as well as using nitrogen as a flue gas for metal work.

If your around in a year I may be interest sir.

Thanks for the interest, please note that this unit does not separate any gases from the air, the resulting liquid will have a similar composition to air (70% nitrogen, 20% oxygen, 3% argon, etc. )

If you can find a gas separation membrane or a machine that can concentrate gases from the surrounding air then you can condense liquids of higher purity.

You say this unit will liquify natural gas?

Yes, easily - methane the main component of natural gas has a condensation point of approx -256F according to google, the cooling unit will easily reach -320F

bump

Good unit for experimenting with high temperature superconductors

I think its legal to ship when you aren't shipping cryogenic fluid, thats technically a hazardous material.

I don't think the price is too high, just I don't have a use for it just yet, and I imagine alot of other people are like that, theres no point to buy it for playing around, its an industrial tool.

EDIT: I would put it on alibaba/aliexpress, I think you would get more hits.

You can sell it to cryoniks. Although its Frosbit does in less space. Sorry it was a joke.

Thanks for offering your product.

Very interesting !
I live in Europe so I think delivery won't be an option for me. However, I would really like to build one myself. It seems that you are using a cryptocooler from a superfilter, do you think this is possible to buy such a device in Europe ? Have you considered selling only the cooling device itself (I mean without the fan and the air duct) ?

These are similar to those yes, I haven't found any information as to if they're legal to export or not. If you have any related information I could probably reship you just the cooling unit itself.

Ok, thanks. I do not know why this wouldn't be legal as it is very different from the cryogenic fluid itself, but I'll try to find out.