Liquid Nitrogen

Discussion in 'Refrigerated Trucking Forum' started by DKS, Jun 13, 2012.

  1. DKS

    DKS Bobtail Member

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    Good day, colleagues.

    I'm looking for people who worked with liquid nitrogen cooling systems. Or people who are interested in this technology.
    Does anyone have any information about sites where you can talk about these topics?
    I think that technology has a future and I want to identify the best suppliers.

    Please, welcome for discussion .
     
  2. bulletproof77

    bulletproof77 Medium Load Member

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    That is kind of "old technology". The major groceries chains in California used to use Ln2 cooling systems on refrigerated trailers years ago. We have very few that use it now. Mainly only containers that are being shipped overseas with certain forms of produce. I still work for the "best suppliers" and if there was a market for it, we would have found it.
     
  3. chalupa

    chalupa Road Train Member

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    Yep, Was used moons ago on overseas stuff. They actually put a VGL on the front of the box and the N2 would "drip" in the box to cool or freeze the product....however a few recievers ended up dead. I haven't seen one of those rigs in 10 years or so.....
     
  4. Dutch

    Dutch Light Load Member

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    Safeway is still using it. They have eco fridge units out of the Ukraine, how ever I believe that company has went belly up. Wabash I believe is now supporting the product. That system sprayed n2 directly into trailer to keep it cool. Another company is running a prototype system baised on conventional reefer system sorta. No n2 is injected into the trailer.
     
  5. Hammilton

    Hammilton Bobtail Member

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    Oooh, a science-y thread. Physics was never my area of study, but chemistry was, and I was always interested in refrigeration. In college I first built a simple "run-ice water through a copper tube, blow fan over copper-tube-coil- run ice water back into ice bath" air conditioner. It was boring so I created an Icy-Ball next. I think I still have it, but I don't use it. I still think they could make a come back for single-room cooling, but anyway....

    The plants I work at use N2, CO2 and Ammonia (well, one of the plants uses N2, CO2 and Ammonia, the newer of the two dropped N2 and CO2 and strictly use Ammonia) so I've seen the systems up close and am very familiar with them.

    Liquid Nitrogen sounds cool and it's neat to see it skitter across the floor, but it's simply not practical. What sort of system do you propose to use it in? You could spray N2 into a trailer, I suppose. That's going to require you to refill you N2 tank constantly though. I can't see anyone wanting to take their 53' trailer and using the first 4-6 feet for an N2 tank when a Thermo King unit sits so nicely on the front! It's really not going to be practical to use in a standard vapor-compression system. You'd need a cascading compression technique of some sort. Nitrogen expands about 700x from liquid to vapor, meaning 1cc liquid yields 700cc of vapor It takes a LOT of energy to compress N2 into a liquid. I haven't begun to look into it, though I probably will now, but I would imagine that the compression phase would generate enormous amounts of heat. Heck, compressing ether into a liquid gets notably hot. That's not taking into account the heat generated by the mechanical processes either- which would be considerable with an N2 system.

    With the exception of very specialized requirements- like extremely low temperatures- there's simply no way that N2 will make a practical refrigerant. There are better gasses which require less energy and produce less heat as they are compressed. Those units are cheap and easy to produce, have high reliability and have no problem getting a trailer down to -5 rapidly.

    If you need to take a truckload of Einstein-Bose Condensate from Cambridge, MA to Berkeley, CA, then perhaps liquid nitrogen would be a good idea....
     
  6. chalupa

    chalupa Road Train Member

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    Ahh yes Hammy but alas, they did.....for awhile, drip N2 into a reefer at a regulated rate to maintain zero aboard ship.

    And yes, N2 mfg generates alot of heat and said heat is dispersed via cooling tower ( from compressor) and the compressed air ( 90lbs @48" pipe) is sent to an expander....the rapid expansion causes it to cool further.

    On a front end clean up plant ( newer tech ) the compressed air passes through a bed of activated carbon to scrub it of moisture and unwanted gasses.

    ASU's are rated on tons of O2 produced in a 24 hr period and N2 is basically a by product. Yes it's sold and needed however it's sales alone won't pay the bills even though you make double plus of it compared to LOX.
     
    Last edited: Jun 22, 2012
  7. DKS

    DKS Bobtail Member

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    I know that Safeway use a bit different placement of the tanks and sprayers. Why I am interesting in Ukrainian systems. A week ago I have discussed some tips with ecoFridge top manager. Technology is looks good and in future it will be first for sea transportation I believe. Do you know that Nitrogen is a secondary product for Oxygen producing companies. Israel run several trucks from ecoFridge and France+UK. Not all of them are first class, but those gyes from Ukraine are rising their technology faster then I have expected.
    The most interesting that is system is extremely easy to repair and run. My friend work on fip as an engineer, you know, he hate diesel coolers, because they are braking all the time)))