A better gel for shipping...TESTED!

Dancing frogs · #1 (**permalink**) 12-05-2006, 06:45 AM

Anyone who has read my rants promoting the use of gel-packs in frog shipments knows how much I recommend them.
I wonder if this would be much better?

http://www.tcpreliable.com/products/pcm/phase22.html

I didn't get good enough math grades to consider trying physics, so if someone has the knowledge, would they care to explain the phase change process as it would pertain to our usage?

This company has a few different gels, all with different phase change points, obviously for different uses.
I have no idea the cost of these, but wonder how much better (if they are) than the generic gels that are more common.

Anyone care to take a stab?

defaced · #2 (**permalink**) 12-05-2006, 08:08 AM

Here's my guess:

When a substance changes phases, there is an isothermal reaction that takes place for an extended period of time. This is associated with the energy the substance is taking in, or releasing. If you engineer a substance to have a very long, isothermal phase change, it would be incredibly thermally stable.

There is one hitch, nature likes energy to be at its lowest state. To satisfy this in our application, you would heat this thing up, it would take in energy during this time and if enough heat were supplied, the phase change would take place. Now when you remove the heat, it will be begin to cool at some rate. When it reaches the temperature of the phase change, it will stay there for an extended period of time (this neglects undercooling whis is usually pretty subtle). Once the phase change is over, it will continue to cool.

Below is a graph for the heating of ice to steam. As you can see, there are two isothermal regions, one when ice goes to water, and another when water goes to steam. If you reversed this graph (put the right side of the left and the left side on the right), you would have the time/temperature graph of water cooling from steam to ice.

So basically, these things are most stable at their phase temperature.

And even if my guess is wrong, if I did a good job, you should understand the concept of latent heat.

pl259 · #3 (**permalink**) 12-05-2006, 02:28 PM

Phase change materials that change at room temperature would certainly be the holy grail of packaging materials. Not sure of the cost though. I used a paraffin based PCMs in an electronics sensor several years ago. The thermal energy from the electronics was absorbed by the wax as it melted, keeping the electronics cool. Afterwards it would revert to it's solid state, ready for the next turn on.

That Phase22 product looks interesting because it's reusable and disposible which means we might be able to find a bio testing company that throws them out.

Here's another one...

http://www.saftpak.com/catalog/CatalogPages12-13.pdf

I'll try to get some samples for testing.

Edit...It looks like the Saf-T-Paks are $6-$7 a piece.

EricG.NH

Dancing frogs · #4 (**permalink**) 12-06-2006, 03:29 PM

I got a quote of $3.60 per panel or $129.00 for a case of 36, for a 5x5x1" rigid panel of the phase 22.
Or roughly 4 times the price of the ones I use now, and due to the fact that they are non-flexable, wouldn't be as easy to pack with. Unless I went with new shipping boxes that would allow that size to fit.
At this point, I don't think it would be worth it, with shipping costs already getting out of hand.
Though I think I will try to get two packs to test...who knows, maybee these things are the cat's meow?

defaced · #5 (**permalink**) 12-06-2006, 06:03 PM

I think it'd be nice to see if there is a difference with our application. If so, I think it'd be a good opt-in thing for a buyer to consider paying extra for when weather is not favorable.

Dancing frogs · #6 (**permalink**) 12-06-2006, 06:21 PM

I'm thinking a returnable deposit for heavyduty packaging, or if selling to a repeat customer or someone you know you can trust, don't add the cost, and simply ask them to return the packaging via the cheapest method possible.
I've done that before...packaging doesn't grow on trees!

defaced · #7 (**permalink**) 12-06-2006, 06:22 PM

I'm doing that with my tanks. 25 dollar deposit on the plywood box and I pay for return shipping. We'll see how it goes.

pl259 · #8 (**permalink**) 12-06-2006, 06:37 PM

Mike and Brian,

A rep is bringing me 4 Saftpaks on Thurs for test. Let me try to get some of these Phase22 to test as well.

I think the potential of these products is huge. Yes, they're a few dollars more then heat/cold packs, but they're resusable. That's not the biggest plus. They will maintain a near constant temp inside our typical insulated shipping boxes, over a very wide range of temps, for a long period of time, likely greater than 36hrs. This not only reduces risk, but extends the shipping seasons. Additionally they may save cost by allowing us to ship using other then overnight services. Further, they don't consume O2. It would also be the same product year round.

This type of shipping solution is what I was going after in the other thread.
One that doesn't care or cares less what exterior temps the package sees. I threw out of contention vacuum panel insulators because of cost.

EricG.NH

Dancing frogs · #9 (**permalink**) 12-06-2006, 07:07 PM

Yeah, if we could do away with the chemical heat packs altogether, I'd be very happy!

Catfur · #10 (**permalink**) 12-06-2006, 08:20 PM

A phase change material at 71 F (which is what these are) is nearly perfect for PDF shipping. As long as you start out the package on the right side of the phase change (over 71F in winter, under in the summer), this ought to add significant temperature stability to the packaging. I had been wondering for a while if there was a phase change material in the 60s to mid 70s range. Now, where do you buy these?