A better gel for shipping...TESTED!

[Dancing frogs]

Well, I got the quote like I mentioned, "$3.60 per panel or $129.00 for a case of 36, for a 5x5x1" rigid panel of the phase 22."
And since the material is 4 times the price what I use now, I asked if I could buy 6 for testing and was told I have to buy by the case.
If someone wants to split some, I may be up for it, I'd really like to try them out.
Pm or email me if interested, or if you want a case for you'reself, there are links to contacts, try them all till you get one to respond (I did).

[Dancing frogs]

Ok, I bought a case of em...

Here is a comparison of the gel packs I was using (8oz soft gel packs from superior), and the phase 22 hard panels.
Both packages were packed the same, in a homemade cooler made from R-10 stryofoam, glued together with polyurethane adhesive, with interior dimensions of 6x6x6". One pack on the bottom. stryro peanuts to keep the data logger in the middle, and another pack on top, with the top of the styrofoam box sealed with tape.
The gels and panels were "charged" similarly, by soaking in hot tap water.
Test conditions were in the freezer, with a temp range of +10F to -3F (sorry, no chart available)
Here is the box using the gels I had been using...

Here is the box using the phase 22...

Sorry for the other traces in there (the red one is temperature in F).

So far I like the results, but designing a package around the 5x5x1" hard pack is a pain, so I think I will drain a few into bags and seal them, to make custom "gel packs".

[gary1218]

What do the phase 22s cost?

[pl259]

Nice job Brian! Thanks for taking the time to run those. I still have my PCMs but haven't had the time to test. Work's still been crazy.

It looks like they both started at close to 90F. Is that right?
It's also interesting the PCM dropped to 10F and the gel dropped slowly after 32F or so. Is there any special reason for this?

I guess I would believe that the area under both of those curves would have to be the same. Interesting how the PCM crashes.

It might be an interesting test using both, one of each. There is only so much energy in the gel packs. One gives it up asymptotically, the other abruptly. Not sure which is the best way to go.

EricG.NH

[joshsfrogs]

It's also interesting the PCM dropped to 10F and the gel dropped slowly after 32F or so. Is there any special reason for this?

The phase change temp of the gel pack?

So at less than 10 degrees the package stayed above 50 degrees for over 12 hours!? I think when you factor in late night dropoff, pickup at the station, and the fact that your freezer is far more harsh than the temps seen in shipping...wow, these things are pretty sweet.

I wonder if we would want the phase change temp a little lower like 55 degrees. At 71 degrees, the phase change could happen soon after packaging and at the hub (68-70 degrees) and then be vulnerable during the rest of transit. Have it have a phase change below 60 would also allow it to gain more energy in transit during times of warming (i.e. loose energy on the tarmac, gain it in the 60 degree cargo compartment, etc.)

[Dancing frogs]

Yeah,
I ought to try leaving the ones with the generic gels in the freezer longer, I'm guessing that their phase temp is somewhere just below the freezing point of water, therefore holding temps in that range steady longer, as thats probably what they are meant for anyway.
I also did a test with water bottles that showed the same response of stabilizing at the freezing point.

They were both charged in hot tap water, so the gel/phase change material were in the 90's at the time of packing.

I kind of had a similar, but different idea of mixing the materials, I was wondering if perhaps a pcm with a lower phase temp would hold the box in the safe range longer, to push the plummet further down the line, but I would imagine the usable time would remain similar, just stabilizing at a cooler temp.
I also think once I get the custom gel packs made (gotta go to work and use a sealer), the results will be better, due to more mass in one place, rather than just the small amounts in the small container, which doesn't effeciently use the space available in my coolers.


The price of the pcms was posted a couple posts back.

[Dancing frogs]

Eric,
Can you post the dimensions of the pcm's you have?

[pl259]

Brian,
The PCMS I have are from a company called SaftPak.

http://www.saf-t-supply.com/shopper_...opperRegionID=

(Not the best website)

I have three each of the STP315(20-24C) and the STP317(15-30C)

They basically are a soft gel pack about 6"x9".

Your generic gels basically have a lot of mass per unit volume, read density, and therefore have a lot of heat storage capacilty.

The PCMS are interesting in that they should also absorb and store energy without changing their temp abruptly. Using them with a heat pack is another interesting approach.

EricG.NH

[sbreland]

Brian,
I was wondering if you did or could do a test just outside overnight in regular temps versus a freezer overnight to see how the phase 22 holds up to more realisic temps. I know we like to play at extremes, but I would be very curious how these things would perform with normal temps (in the 20-30s) overnight versus what a freezer put them through. I may not understand the concept completely, but would a warmer temperature (versus that of the freezer) not let it stay stable longer?

[Dancing frogs]

Same box, packed the same way (with 2 phase 22 packs) in the fridge, 37-45F: