Make Your Own LN2 At Home (24/7 LN2 Cooler Imminent)

1 liter a day ... that means I only have to wait 180 days to fill my 180L dewar. Maybe if the build is bigger, the cost of $1.15/liter can even drop a bit.

You can generate liquid nitrogen (LN2) in the comfort of your own home with some parts found on eBay. I have proven that this is possible by purchasing surplus equipment and assembling it as described in this post. I spent over a year searching eBay, so these parts are not really easy to find, but the total bill for the whole system was under $500. The device consumes about 300 to 400 watts of electricity and needs no consumables (just atmospheric air). The LN2 is produced at a net rate of about 1 liter per day. This comes out to 9.6 kWh/liter or $1.15/liter, which is substantially cheaper than having the local welding store fill up a thermos (granted the thermos must be cooled as it is filled, thus requiring more than its capacity of LN2).

The most important part of this system is the cryocooler. This is a device that employs a thermodynamic gas cycle to pump heat through a very high temperature gradient. Many of these devices are self-contained and require only an electrical input to start pumping heat. The crycooler that I used was removed from a surplus RF filter which used the cryogenic temperatures to maintain a superconducting RF filter. The crycooler itself has been fairly well documented.

I converted the cryocooler to be water-cooled on the hot end and attached a heatsink to its cold end. In operation, the cold end with the heatsink is inserted into the top of a large dewar. Eventually, the interior of the dewar gets so cold that the air will condense into a liquid and drip down to the bottom. The second key part of this system is the nitrogen separation membrane. The is a device that accepts normal air, and produces relatively pure nitrogen. The waste products (mostly H2O, O2 and CO2) are vented into the air.


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Eeky NoX says:

A must have if no LN² retailer in the country ! Awesome ;)

Slovenia tiborrr says:

The design itself has a few flaws but it's a good start :) Besides, 1L/day isn't enough as most dewars leak about 0.3-1L per day. This is the device you need: http://www.elan2.com/products.asp It produces up to 6L/day, but it draws 900W. 24h*0.9kW= 21.6kWh for 6L, that's 3.6kWh/L . Here in my country the electricity rate is about 0.1e/kWh so 1L would cost about 0.36€/L. Quite nice :P

Belgium Massman says:

Yeah, but what are the initial costs for the generator?

Russian Federation Antinomy says:

tiborrr

The elan2 Office Liquid Nitrogen Generator has the ability to produce between 4.5 L and 6 L of liquid nitrogen every 24 hours...
it is stored in an internal 0.75 L reservoir...
Once emptied, the internal reservoir will fill back up in 4 to 6 hours.
Someone's fooling with the numbers -
0.75/6*24=3
0.75/4*24=4.5

Looks like they have problems with math. And the price is unknown being compared to 500$ which is more than cheap for this stuff. The only problem is the LN2 evaporating while being filling up the dewar.



And yes, this article is awesome!

Slovenia tiborrr says:

Antinomy: The price of ELAN 2 is around 8.000,00 USD :D

Iran PUMAOC says:

ommmmmmmmmm! :d

Iran nasiban says:

wow nice way for me . thanks for sharing

Russian Federation Antinomy says:

tiborrr, oh, that's a really cheap one. All such things I've seen were about 10-15 times more expensive :D Even the DI generator was about 10.000-15.000 USD :)

Austria Turrican says:

damn, nice thing i must say. :D

United States Hondacity says:

idea is nice.....i don't want to pay 200$ a month for electricity though...200$ is 150L already :D

United States G H Z says:

Pretty cool, it's an initial step. Now we need a 5L per day unit that's even more efficient.

United States Gomeler says:

I looked into doing this a while back. The problem is getting a stirling heat pump that isn't 1) gigantic 2) tiny. The author of this article mentions this; there are either heatpumps meant for generating hundreds of liters per hour or for generating a few deciliters per hour. For our purposes we need one that produces ~1 liter per hour.

United States G H Z says:

Think 'cascade' chris ;)

Slovenia tiborrr says:

Gomeler said: I looked into doing this a while back. The problem is getting a stirling heat pump that isn't 1) gigantic 2) tiny. The author of this article mentions this; there are either heatpumps meant for generating hundreds of liters per hour or for generating a few deciliters per hour. For our purposes we need one that produces ~1 liter per hour.


This. :nana:

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