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Emergency refrigeration - Which system is best?

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posted on Mar, 8 2014 @ 05:32 AM
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One of the biggest issues when the world goes haywire is stopping fresh food from spoiling. Refrigeration is a luxury that many of us take for granted, but when the power goes out the clock starts ticking on all that food you have stored away in there.

In this thread, I will present the three main versions of offgrid refrigeration (also used in camping) and their advantages / disadvantages in order to help you decide what is most suited to you.

There are a few things that need to be taken into consideration before deciding what type of fridge will suit you best

A) The climate you live in. For example if you live in a place that rarely gets above 25degrees you are spoiled for choice, whereas if you live in the hottest city in the world like I do, you need a seriously heavy duty unit to keep those beers ice cold.

B) Availability of alternative power / gas supply. Some fridges are wonderfully cheap to buy, but hog electric current, so you will need a really good battery pack to keep it going or a generator etc.

c) Where you want to keep this unit. i.e. do you want a backup for home, do you want it to be stationed in your vehicle in case of a situation where you need to flee your immediate surroundings etc.

So, bearing all of that in mind, on to the types of fridges available;

Thermoelectric coolers



Advantages

Cheap and plentiful. You can even make your own one if you cannibalise the cooler off the CPU off an old computer and put it in an ice box. The good ones (high efficiency models) can cool up to 30 degrees below ambient temperature.

Disadvatantages

They run all of the time and therefore need a constant supply of electricity. The average one will draw around 45 watts (just under 4 amps) constantly. Relatively low ambient cooling capacity (usually around 20 - 25 degrees below ambient temperature) this can be an issue in warmer climates. Take a long time to cool down, so food / beverages are best pre-cooled before putting them in. Unable to be used as a freezer.

Most suited to

Cars on the move / hooked up to a generator. As they need a constant supply of electricity, they are great for in the back of the car on a long trip because the alternator will power it, alternatively they are fairly economical if a generator is already in use.


Three way coolers



Advantages

Multiple power options. Come in all sizes, from small portable fridges to regular home sizes ones. Economical on gas and when installed correctly good ambient temperature cooling ability (up to approx 40 degrees below ambient). Can also freeze and have the extra option of being powered by propane gas.

Disadvantages

Not really suited for vehicles on the move due to the fact they need to be kept level in order to operate at 100% efficiency. 12v power consumption is extremely high (usually starting at around 120w or 10 amps) Like thermoelectric coolers, they take a long time to cool down and primarily rely on insulation to retain the cold when it starts to get warm.

Most suited to

Semi / permanent situations i.e. mounted in a caravan / RV / offgrid home / base camp.

Compressor fridges



Advantages

These are basically re-engineered versions of the fridge sitting in your kitchen. Available in a large range of sizes like three way models. They feature small a small compressor that is optimised for 12v, are very forgiving of inclines when driving and are by far the most popular choice where I work. They have by far the best ambient cooling capacities, with some managing up to 50 degrees below ambient temperature. As a result they make excellent freezers.

Disadvantages

Like thermoelectric coolers they need an uninterrupted power supply, however they are thermostatically controlled and do shut off in lower temperatures (just like your regular home fridge) Most expensive of the three options.

Most suited to
Solar set ups, high ambient temperature situations, pretty much any situation so long as you can get power to it.

edit on 8-3-2014 by markosity1973 because: (no reason given)




posted on Mar, 8 2014 @ 05:53 AM
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Add in "Stirling cycle cooler" - they're like compressor rigs, but more efficient. Albeit somewhat pricey.



posted on Mar, 8 2014 @ 05:58 AM
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reply to post by Bedlam
 

A much simpler idea than Stiring cycle coolers is eutectic systems.

They usually use a water jacket with a compressor to freeze them up, but are rather energy hungry, costly and are not readily available on the mass market.

edit on 8-3-2014 by markosity1973 because: (no reason given)



posted on Mar, 8 2014 @ 06:14 AM
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reply to post by markosity1973
 


In preparing for TSHTF, it seems idealistic to be thinking about flipping an alternative switch on some emergency unit you have on standby to maintain cooling for food. Given a full-fledged bad situation you won't have electricity, water or protective services perhaps for weeks. A typical person's ability to acquire, maintain and provide power for such units is way beyond being practical unless you have big bucks and a roomy, solar-powered bunker, etc. Never take for granted that you will remain in your current location given a time of crisis.

Better to study the art of drying, salting and storing foodstuff as done in the days before chilled air became all the fashion. Your hands and knowledge of how to overnight regress to a primitive lifestyle will be what saves you. And none of that involves much of anything mechanical.



posted on Mar, 8 2014 @ 06:15 AM
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reply to post by markosity1973
 


yeah, but I'd assume if you were on the run, something energy hungry and large wouldn't be a prime choice.

My first pick if I were to set up camp would be an ammonia cycle freezer, possibly converted over to solar. Freeze water during the day, use it to load up high R number coolers like a Yeti.



posted on Mar, 8 2014 @ 06:24 AM
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The dc compressor fridges work fine and last a long time ,current one about 10 years of constant use ,but Most camping fridges hold bugger all ( cost twice as much for dc compressor types) a couple of weeks worth at best .You can still keep your water and vegies cold or freeze a bag full of rodents.best spend your cash on non perishable if your planning long term living quality as opposed to panic mode and eat everything on the first day
edit on 8-3-2014 by 12voltz because: (no reason given)



posted on Mar, 8 2014 @ 06:26 AM
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I would go with propane fridge running on wood gas via my gasfier that also heats my house and runs my generator.



posted on Mar, 8 2014 @ 06:30 AM
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Refrigerators can also be powered by firewood. Propane refrigerators that is. They did this in WW2.



posted on Mar, 8 2014 @ 07:47 AM
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If you are in an area with lower humidity and a slight breeze then the Zeer Pot bears mention as it need no electricity and can in normal conditions will achieve 10 degrees or more lower than ambient temps.
Will it frost your beer? No.
Will it allow you to keep fruits and vegetables for 20 days instead of 2? Yes.
It would probably never reach the magic 40f needed to inhibit bacteria growth so no meats or delicate foods prone to the bad stuff.
Further more if one was to improve on the efficiency for the basic method of function by forced air (12v computer fans) around the outer vessel evaporation is increased which increases the cooling effect in the inner pot.



Ak.



posted on Mar, 8 2014 @ 05:23 PM
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reply to post by markosity1973
 


Some really great information presented here. Are you familiar with The Einstein–Szilard Refrigerator? It's an absorption refrigerator which has no moving parts, operates at constant pressure, and requires only a pilot light for a heat source to operate and has a potential operable life of 100 years.

phys.org...

en.wikipedia.org...

www.etsy.com...








posted on Mar, 8 2014 @ 05:39 PM
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This usually works pretty good:




posted on Mar, 8 2014 @ 05:43 PM
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reply to post by peter vlar
 

Thanks for the pics


Yeah, the Einstein fridge is very similar to a three way in that it boils a liquid who's steam (somewhat counter intuitively) is actually cold.

The main reason I presented the three systems I did is because they are readily available on the market today for anyone to purchase. I am loving all the other technologies people are sharing too though, it's a shame some of them have not come to market in commercial quantities.



posted on Mar, 8 2014 @ 06:26 PM
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Several other things to consider.

Wrap the freezer up in more insulation, lots more.

Open it up only once a day to get supplies out for that day.

Once the food is frozen, you only need to run it once a day.

An ordinary household chest freezer with additional insulation is the way to go IMHO. Run it once a day from a generator ot run it from a solar array.

Keep the freezer in a cool environment, like a cellar or a pit.

P



posted on Mar, 8 2014 @ 06:33 PM
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If you're in the right place, you can build a spring house. My grandparents used them when they were kids.



posted on Mar, 8 2014 @ 06:42 PM
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pheonix358
Keep the freezer in a cool environment, like a cellar or a pit.

P


This is one of the better pieces of advice that are available in nearly all scenarios unless you're on the move or in an area with a high water table. If you have the ability to dig down 4 feet or more below the frost line, you're already off to a good start because the year round ambient temperature is going to be right Round 50 degrees Fahrenheit. If you're using even an inefficient setup that can drop you 20-25 degrees below ambient temp you have the ability to freeze items as well as just refrigerating them. Somentimes what initially appears to be a complex issue can be solved with not a lot of difficulty if you can put in the time to do your homework and willing to get layout hands a little dirty.



posted on Mar, 8 2014 @ 07:33 PM
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I've always liked the idea of a solar ice maker such as this:

knowledgeableideas.blogspot.com...

Basically, it would make large pieces of ice that would be used to fill an ice box to keep your perishables cool. And thus means you also need a supply of water to make the ice.



posted on Mar, 8 2014 @ 08:24 PM
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reply to post by allenidaho
 


A great example of how to take advantage of solar belt areas like where I live. It's basically the guts of a three way fridge modified to heat by the sun instead of gas. You could probably also light a fire under it to make it work at night if you used the right materials.



posted on Mar, 8 2014 @ 08:35 PM
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reply to post by markosity1973
 


In the phys.org link I had posted with the Einstein refrigerator links they talk of a guy in England who is trying to develop a commercial model that would run off of solar power instead of gas or wood making it very suitable for equatorial 3rd world nations or any area that gets a lot of unrestricted sun light.



posted on Mar, 9 2014 @ 01:23 AM
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reply to post by peter vlar
 

Slightly off the topic of survival, but I have often wondered about the viability of using the same tech to make solar powered air conditioning. In theory you could run the cooling pipes through the ceiling (cold air falls) and have the solar unit on the roof.

Imagine how much energy could be saved if it were possible to make a viable unit.



posted on Mar, 9 2014 @ 01:33 AM
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markosity1973
reply to post by peter vlar
 

Slightly off the topic of survival, but I have often wondered about the viability of using the same tech to make solar powered air conditioning. In theory you could run the cooling pipes through the ceiling (cold air falls) and have the solar unit on the roof.

Imagine how much energy could be saved if it were possible to make a viable unit.


At one time, I looked into that, there are (or were) prototype solar powered air conditioning systems using ammonia cycle cooling, but they didn't seem to be something you could get off the shelf. Chez Bedlam is going to go all solar after I get done with this job (Neverending contraaaaaact aahhaahha neverending contraaaaact...). A solar powered AC would be a BIG help. I want to go off the grid and keep all the toys.

eta: at one time you could get gas fired AC off the shelf from Arkla-Servel, but these units were from someone else...

edit on 9-3-2014 by Bedlam because: (no reason given)







 
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