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#180456 - 08/26/09 04:53 AM Re: Emergency rations for storage in a car? [Re: Susan]
dweste Offline
Pooh-Bah

Registered: 02/16/08
Posts: 2463
Loc: Central California
Way to go to the horse's mouth!

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#180466 - 08/26/09 10:21 AM Re: Emergency rations for storage in a car? [Re: dweste]
celler Offline
Addict

Registered: 12/25/03
Posts: 410
Loc: Jupiter, FL
Sounds like Mountain House believes taste will be effected, but they did not say anything about heat making the food inedible. I will be very interested to see the results of Compugeek's test with the high-low thermometer and the insulated cooler. It might be possible to control the temperature sufficiently to give you more than one summer of "trunk life". It would be nice if someone in Texas or Florida has the equipment to do a similar test.

Craig.

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#180487 - 08/26/09 12:59 PM Re: Emergency rations for storage in a car? [Re: celler]
Compugeek Offline
Enthusiast

Registered: 08/09/09
Posts: 392
Loc: San Diego, CA
The test is in progress. It's hard to resist posting partial data, but my High School Physics teacher would probably hunt me down if I did. smile
_________________________
Okey-dokey. What's plan B?

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#180601 - 08/27/09 04:48 PM Re: Emergency rations for storage in a car? [Re: Compugeek]
Susan Offline
Geezer

Registered: 01/21/04
Posts: 5163
Loc: W. WA
My knowledge of physics is minimal: if you step off a cliff you drop straight down, and if you're on a motorcycle and hit an immovable object, your body keeps going if there is no wall in front of you.

One thing on this subject has always made me wonder...

In extremes of temperature, would multiple+multiple+multiple layers of insulation prevent something from freezing or overheating, or would the outside ambient temperature still get to the item over time (maybe more slowly, but eventually).

To mitigate that, may I assume that you would need some source of coolness to keep something cool, and some source of heat to keep something from freezing?

I have always assumed this was the case, but when I ask people a question like this, I always get funny looks, like they're thinking, "Why would it matter?"

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#180605 - 08/27/09 05:26 PM Re: Emergency rations for storage in a car? [Re: Susan]
paramedicpete Offline
Pooh-Bah

Registered: 04/09/02
Posts: 1920
Loc: Frederick, Maryland
Quote:
In extremes of temperature, would multiple+multiple+multiple layers of insulation prevent something from freezing or overheating, or would the outside ambient temperature still get to the item over time (maybe more slowly, but eventually).


Correct

Quote:
To mitigate that, may I assume that you would need some source of coolness to keep something cool, and some source of heat to keep something from freezing?


Correct

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#180608 - 08/27/09 05:38 PM Re: Emergency rations for storage in a car? [Re: Susan]
ducktapeguy Offline
Enthusiast

Registered: 03/28/06
Posts: 358
If the temperatures were to stay consistent throughout the day, then even with the best insulation the temperature of the item will eventually reach equilibrium without any extermal source of heating or cooling.

However, since the temperatures vary, what the insulation can do is mediate the temperature extremes. So if the peak temperature was 100 degrees, and the low was 50 (and assuming a balanced temperature graph on each side), a well insulated item would average around 75 degrees (+/- some amount), depending on the insulation and where in the car it is stored. Most likely you would see a shift in the temperature peak where the peak temperature of the item could be well into the cooling cycle of the ambient temperature. If youv'e ever opened a car door after a hot day and wonder why the inside is so much warmer than outside temperature, it's because the car itself is acting as an insulator.

Storing item in a styrofoam cooler or insulated bag is a cheap way to protect any sensitive items in a car. When I used to carry camera equipment in the car that's what I did. Even during the hottest day where the interior of the car would be too hot to touch, the items in the cooler were still comfortably warm. Not a very scientific test, but good enough that you could tell right away it was effective.




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#180616 - 08/27/09 07:10 PM Re: Emergency rations for storage in a car? [Re: ducktapeguy]
unimogbert Offline
Old Hand

Registered: 08/10/06
Posts: 854
Loc: Colorado
Originally Posted By: ducktapeguy


However, since the temperatures vary, what the insulation can do is mediate the temperature extremes. So if the peak temperature was 100 degrees, and the low was 50 (and assuming a balanced temperature graph on each side), a well insulated item would average around 75 degrees

Storing item in a styrofoam cooler or insulated bag is a cheap way to protect any sensitive items in a car. When I used to carry camera equipment in the car that's what I did. Even during the hottest day where the interior of the car would be too hot to touch, the items in the cooler were still comfortably warm. Not a very scientific test, but good enough that you could tell right away it was effective.



I've had different results.

One should consider that in summer the interior temp of the car is more like 120 or even hotter.

I've tried to protect electronics in a cooler during summer Colorado days. For a full day's heat soak a frozen bottle of drinking water in the cooler was required to keep the soft-sided cooler from letting the electronics get hotter than body temperature by mid-afternoon.

While it would be nice to have passive thermal control, I don't think it's easily achievable. But "easily" is a relative concept.

Other- I've used an IR thermometer to measure paint surface temps here. Black car read 175 while white car read 120 on a 99F summer afternoon. No black cars for my family!

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#180627 - 08/27/09 09:08 PM Re: Emergency rations for storage in a car? [Re: unimogbert]
ducktapeguy Offline
Enthusiast

Registered: 03/28/06
Posts: 358
True, one important thing I forgot to stress was you have to keep things out of direct sunlight. Once the items are in direct sun, then all bets are off because the radiation from the sun makes things a lot hotter than the ambient temperature, so temperatures can easily skyrocket. So usually that means storing things in a trunk, or at the very least throwing a towel over the cooler to keep the sun off. Also, one of those reflective sunshades in the windshield helps a lot, anything you can do to keep the sun out will keep your car cooler. I remember this issue used to come up on photography sites a lot, back when film was still popular.

Here's a pretty good graph showing the interior temperatures of a car over time.

http://www.randomuseless.info/318ti/temperature/interior_temps.png

Just by placing items in different areas of the car you can reduce the max temps by 20-30 degrees. The important thing to remember is all you're trying to do is buffer the temperature extremes. You will never be able to keep it at a constant temperature without active cooling, because given enough time, the temperature will always equalize. All you want to do is insulate it enough to make it through the hottest part of the day until it cools down again.

FWIW, those soft sided coolers never really worked for me, I think the zippers just couldn't get a good enough seal. I used one of those cheap styrofoam cooler that they ship frozen things in. The styrofoam was about 2" thick and it had a tight fitting lid. It seemed to insulate better than any other cooler I've ever used, plus it was free.


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#180672 - 08/28/09 12:15 PM Re: Emergency rations for storage in a car? [Re: ducktapeguy]
unimogbert Offline
Old Hand

Registered: 08/10/06
Posts: 854
Loc: Colorado
Originally Posted By: ducktapeguy


FWIW, those soft sided coolers never really worked for me, I think the zippers just couldn't get a good enough seal. I used one of those cheap styrofoam cooler that they ship frozen things in. The styrofoam was about 2" thick and it had a tight fitting lid. It seemed to insulate better than any other cooler I've ever used, plus it was free.



I concur. My softsided coolers don't help much at all. The hard-sided plastic cooler is a little better but the best cooler I've used was a disposable styrofoam job with tight fitting lid. Only lasted 15 years though. :-)


Edited by unimogbert (08/28/09 12:15 PM)

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#180693 - 08/28/09 05:48 PM Re: Emergency rations for storage in a car? [Re: unimogbert]
GoatMan Offline
Member

Registered: 08/17/07
Posts: 100
Perhaps a thermoelectric cooler would do the job. Some can both cool and heat. You would have to find one with a flexible thermastat to get the temperature right. If it is connected to a DC outlet that only powers up when the car is running, then it will work to either warm or cool the stored food until the car is parked. At that point it will then insulate it from the outside until it is powered up again.

This doesn't really help James since he doesn't want the bulk, but it seemed like a noteworthy idea.

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