Post by dlzc...
Post by l***@gmail.comI think you have the best answer so far, maybe
working on an insulating material that is of
"alien" origin, that can perform miracles
would be a better method to keep something at
about -20 C, or at least below 0 C for about
10 days.
The closest in real life would be aerogel, but the cost of using it
would be astronomical so the packaging would have to be recycled.
http://en.wikipedia.org/wiki/Aerogel
A design that is a sandwich of basic polystyrene around the outside,
aluminium foil radiation shield then aerogel and then the dry ice and
load might get close to the required performance on a good day.
You can ameliorate ingress of heat in the sun by putting fins on the
package so that it is partially self shading like cacti and desert
dwellings with verandas. Also white exterior and mirror finish interior
of the box with air allowed to freely circulate the first outer skin.
Post by dlzcBatteries and Peltier coolers, with a very high deposit on the shipping container.
No chance. Even a tethered system would need several amps and a very
*BIG* heatsink to dump the waste heat into.
Post by dlzcPost by l***@gmail.comThe total mass should be less than 1 or 2 Kg,
and about the size of a large cup of coffee in
volume maybe.
Better to let Fedex charge your customer.
The requirements are impossible without the cooperation of the airline
or shipper to provide active cooling when it is on the ground.
Post by dlzcPost by l***@gmail.comThe problem, using gel-packs or dry-ice for
transnational shipping of boxes that are 12"
cubed or smaller, using 2" styrofoam with 2 Kg
of dry ice or gel packs at room temperature
with internal contents at -20 C only last 2
days on average, and even with 50 lbs of dry
ice and a huge box, we're talking 5 days i
think, let alone the cost of shipping.
Packages spend a lot of time on the tarmack, unless they are treated as needing to be kept cold (or warm, or dry).
They often spend some of it upside down in puddles which is why we
always had tip tilt detectors on all our shipments. It takes a lot of
physical abuse to mangle a 19" rack instrument system but they did it!
Post by dlzcPost by l***@gmail.comThe current solution is freezers during shipping
points from China to USA for example with FEDEX,
but that raises costs to hundreds or thousands
of dollars.
http://www.fedex.com/us/healthcare/temp-control/
... sure, because the shipper assures that the load stays cold.
You have to pay for this service and with good reason. I can't see them
accepting anything with LN2 onto an aircraft.
Post by dlzcPost by l***@gmail.comI'm looking to find a solution, and to patent
it, so if you want to discuss this more email
me somehow.
You will need the buy-in of the shipper, because they can and will fail any attempt to bypass their profits.
You might get away cheaper to give to a courier, then ship refrigerated Fedex once in the country of interest.
David A. Smith
With biological specimens you run into all sorts of delays at customs
too. A researcher I know had some specimens of elephant urine impounded
at UK customs and delayed enough to be scientifically worthless.
Everyone had forgotten about it until six months later a letter arrived
telling him that if he did not collect his specimens of stale elephant
urine they would be auctioned off at the next unclaimed items sale!
--
Regards,
Martin Brown