To design a refrigeration container to transport precious cargo, at -70oC by sea. Allowance for heat loss?

Question

The cargo, would be blast chilled to -70oc. Therefore the container (40foot) would be required to maintain that temp. Thus the main consideration would be heat loss/peneration during transportation.
Assistance on this would be much appreciated.

Answer 1

And when do we have to have your homework in by?

Answer 2

You have intrigued me...what cargo needs keeping at -70 degrees?

Anyway... to answer the question. The heat/cold loss through a 40' container will depend on the length of the sea journey. If the sea journey was as much as a week you wouls lose a significant part of the -70 degrees you started with. A well insulated container, especially in summer, would keep the temperature at -70 degrees for not much more than one day, perhaps two.

The usual solution to transporting cold containers is to have self-cooling containers that are powered to maintain the selected temperature. I doubt there is any insulation system suitable for a 40' container available anywhere that would maintain this low temperature for more than 48 hours, though a powered system could maintain it almost indefinitely.

Good luck with your quest.

Cheers,

BobSpain

Answer 3

You need to look at cryogenics and cryogenic transport. Trailers with fridge motors could not maintain freezing at -75C. Most are working at full capacity set at -25C.

To achieve the sort of temperatures you are talking about, the only way would be to use liquid nitrogen or carbon-dioxide as dry-ice, but that would be very difficult to incorporate into a 40ft fridge-trailer.

Such a trailer may exist, but having worked with refrigerated transport, I don't know of any.