Liquid Nitrogen Dewar Container, Cryogenic Storage & ...

Let us know or ask anything by filling out the form below. One of our laboratory equipment experts will get back to you within 24 hours For more information please call +1 (860) 436- or us at [ protected]

Goto Runfeng to know more.

Are you interested in learning more about what is a “dewar”?? Contact us today to secure an expert consultation!

Scilogex only guarantees quality and excellence. Serving laboratories for all areas of research for many years already, we offer a wide range of innovative benchtop equipment designed to meet requirements and budget of virtually any laboratory. Operate at your highest level of efficiency with our advanced line of liquid handling and laboratory products manufactured by our partners in ISO facilities and are UL approved with cTUVus and cSAus certifications.

Always customer-focused, we make sure our patrons are given the best deals, warranties, and customer service in the market. Trust our laboratory experts to provide not just exceptional pre-purchase support but also unparalleled product recommendations.

I have been playing around with a few numbers hoping to really see if there is an advantage of one over the other. Now this is not taking into account that LN is much colder then DI. I'm just assuming if your considering DI then the -100° is ok and you don't need the -300° of LN. My therie has been that even though LN is more money and requires a dewer it's more cost affective in the long run. So let's start crunching some numbers. From here on out dry ice will be shortened to DI and liquid nitrogen will be LN.

First up we need to start by looking at the amount of heat energy each can absorb befor turning into a gas.
DI = 246 BTU/lb (Latent heat of sublimation)
LN = 856 BTU/lb (Latent heat of vaporisation)

Next up let's look at the density of both of them.
DI = 97.6 lb/ft^3
LN = 50.2 lb/ft^3

Let's compare these numbers to what a 20L dewar holds.
20 Litters = . ft^3
20L of DI = 68.934 lbs
20L of LN = 35.456 lbs

Now we can convert those numbers to actual Latent heat
20L DI = 16,957,76 BTUs
20L LN = 30,350.27 BTUs

Next up is price, I will use the prices local to me.
LN = $3.26L and DI = $1lb
Which means 20L of both costs
68.934lbs DI = $68.934
20L LN = $65.2

Now for fun let's figure out cost per btu of latent heat
20L DI = 16,957,76 BTUs / = 16.kbtu
20L LN = 30,350.27 BTUs / = 30.kbtu
DI Cost is $68.934 / 16.kbtu = $4.065kbtu
LN cost is $65.2 / 30. = $2.148kbtu

Now is where it gets a little fuzzy as the math would be complicated so we can just do some guessing. Let's say it takes btus of energy absorbing to cool a knife. That means it cost you $4.065 for DI or $2.148 for LN. But I think the numbers are further apart then that because LN is used as is where DI is usually mixed with a liquid. It uses dry ice to cool the liquid as well as the blade where the LN just has to cool the blade.

Let's dig deeper if we can and see what we uncover. 1kbtu of DI is 4.065lbs which has a volume of
97.6 lb/ft^3 / 4.065 = .ft^3 x 28.317L/ft^3= 1.18L
So if I assume a 50/50 mix of DI and say denatured alcohol which has a heat capacity of around .58 BTU/lb f.
1.18L of alcohol weighs 2.05 Lbs
Which means going from say 68° to -109° would require 177° drop for 2.05 Lbs at .58 BTU/lb F which is 210btus. Now you have wasted 210BTUs just to cool the alcohol and your now left with 790btus for your blade(s) which means you need more DI to make up for the loss. You now need 26.6% more DI to hit your btu requirement.

Now if we look at the cost for btus
btu of DI = $5.146
btu of LN = $2.148
So by looking at the math it seams like LN is much cheeper then DI by almost 2.5x

Now up to this point we have just ignored the fact that you buy DI as needed and LN is usually stored until needed. So let's look at that and see how the numbers look. My dewar is very efficient at a published evaporation rate of .09L/day. This means each month (30 days) it costs me 2.7L x $3.26 = $8.802 to have it on hand.
So if we used say btus once a month for one knife batch then the cost goes up. Let's re do the numbers
DI = $5.146 month
LN = $10.95 month

But where I think LN has an advantage is in only using what you need. Where DI is used up no mater how much was actually needed. Another thing is trips to town to get the DI. Say I only did one batch a month, for me to drive and pick up DI it's a 50mile round trip and about 1.5hr time. My truck gets 13mpg which is 3.85gal @ $2.70gal is $10.395 added cost plus my time. I fill my LN dewar once and it lasts for a very very long time but let's do the math while we are at it.
LN = 1,517.5btu/L but we only use btu each month. This means each month we use .659L plus the evaporation amount of 2.7L. Each month I would use a total of 3.359L. My dewar holds 20L so that's 5.95 months of use before needing to be refilled. So take the trip cost and divide it up to see what the trip costs per month for LN. $10.395 / 5.95 = $1.747
Let's redo the math now
DI = $15.541 month
LN = $12.697 month

So as you can see the cost is neck and neck but LN is cheeper. If you only do cold treatment once in a great while then dry ice is your baby. But you can see if you do any kind of volume then LN has the edge plus the huge time saver of always having it on hand and being able to cryo any time you want. But this also brings into light some other questions like maybe using a tiny dewar for the guys that only use it once in a blue moon. This way you save the storage waste but you still have the trip to town waste for each fill up. But then what if you put dry ice and alcohol in a dewar, oh man my brain is going to explode.

For more information, please visit argon dewar.