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keeping your stuff cold

 
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So .... you take the balloon outside and stretch it - then go inside your freezer and let it get small.  I know it sounds dumb, but stupid statements like this are (i think) the foundation for good ideas. 

Would this work on a spring too?  Like a windup toy?

 
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Sure, that would pump heat.  The stuff in a commercial fridge has a better theoretical efficiency and makes for a more reliable system, but the way it works is analogous to what you have described.

You could also have a belt on two gear-driven wheels, running through an insulated box through two narrow slots with baffles.  The belt is stretched tight for the section that runs outside the box, but runs loose inside the box.  As you turn the crank, the stretched portion of the belt warms up, and the loose portion cools down.  That way, there wouldn't be much air flow to undo your heat-pumping work.
 
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paul wheaton wrote:
Yeah, I think when we're being goofy, "magic" is a great word.  But when we're trying to figure something out, I always thought the term "magic" reflected poorly on everybody - especially the person using the word.

I readily admit that I am fishing around for knowledge and throwing lots of goofy ideas out there in a feeble attempt to expand my knowledge. 

But hey, if this is what it takes to get the ole explain-er-a-tor going, then I'll have to do this more often!

Erica,

What do you think of the idea of ....  (I'm gonna make up a word) a thermal inertia freezer?  Where you have a root cellar that has a very large umbrella keeping a large mass of dirt dry around the root cellar.   And then you have a tube (or two) running through the thermal mass - and you open that tube (and maybe encourage air to pass through) when the temp is below zero. 



Hope that means you've recovered from my use of the "m" word  

No insult intended, just some irritation:
Sympathetic magic-al thinking confuses similarity with cause-and-effect. 
Air and cold often occur together; therefore by applying air, we get cold? 
A ram-pump works on water, therefore we can use it on air?  (I think ram-pumps rely on water's relative incompressability; in any case, they're inefficient and noisy, and other pumps even hand-cranked ones are often preferred.)

And most of all, "it's cool, therefore it can freeze things."
It's like the assertion that dry ice, because it is "boiling," is "so cold that it's hot."
Dissonance in my mind... someone is not understanding the physics of state-change again.  It's like the Bat Signal.
  Yes, you're fishing around for knowledge - but at least give us some juicy bait!
  If you've seen a device that operates on unusual principles, post a link or give some details to explain its apparent violation of natural laws.
  Or at least acknowledge that you know the orders of magnitude involved, and have some reason to believe it would work anyway.  Otherwise, it's easy to associate these off-the-cuff ideas with many other wacky, but ultimately unworkable, ideas from armchair inventors.

   A windmill could probably run an air compressor, but it would involve a lot of moving parts, probably electricity or some kind of energy storage, and substantial losses of energy. 

What scientific laws are being ignored here?
Mostly, the horrible amounts of energy involved in actually freezing stuff.
Turn off your freezer for a month, and check your electric bill.
Put a bunch of warm food in your freezer, turn it back on, and check your meter.
HUGE amounts of energy are involved in actually freezing things.

Also, the relative heat capacity of air, water, food, and dirt.
Air does not carry HUGE amounts of energy compared to its weight or volume.
See the link at the bottom for "specific heat capacity" of water and some masonry materials.

The air-cooled root cellar:
Sounds like it would be similar to an icehouse without the ice,
or a cold closet that you close off (with good insulation) when it's too hot.

Sounds like you're thinking of using the thermal mass of the dirt, actively instead of passively - not sure why you're trying to keep it dry, for insulation?

Depending on how low your outside temperatures get, it could work as a cooler.  Especially for those back-and-forth seasons like Indian summer. 
We used to open our windows at night, and close them in the day during summer:  it does help.  Thermal mass in the house helps a lot more, to maintain your seasonal average temperature, and can be cheaper.

You want to let air blow through the pipes.  There's not a lot of heat capacity in air.  "Water has a heat capacity about 4 times that of air" says the magical Interweb.  That's PER GRAM.  By volume, water has about 4,000 times the heat capacity of air.  (See "specific heat capacity" link below.)
And air going through small pipes experiences something called laminar flow, where the stuff at the sides of the pipe slows down / experiences a lot of friction.  It's one reason why tiny rocket stove models don't work the same as big ones.

If you're trying to draw heat out of your chiller, you might be better off drawing chill water from a nearby stream (shady rapids with lots of evaporation, or snowmelt, are good sources of water chilled by the natural heat losses involved in recent state-change).

But then, we use the gas to directly heat Rocket Mass Heaters, and it works OK.  We only do it that way because the gas is the thing that's hottest in the first place; it's about 300F hotter than the thermal mass.  And it's easy to get wood, and store it for use when we want it. 
If we had access to geothermal hot water, that would be much more effective than hot gas, even at lower temperatures, and we wouldn't bother burning stuff to keep warm. 

Your outside air temperatures aren't going to be that much colder than the cellar - maybe 50-60 degrees colder on a very cold day. 
Places that get 80 to 150-degrees of chill below ground temperature (meaning they get temps from -40 to -110; the ground is colder there too...) tend to have reliably chilly weather, plenty of ice to harvest, and no problem keeping food cold.  Selling freezers to Eskimos, don'cha know.

  So for most climates, you're looking at very gradual cooling from 55 to a few degrees below that - maybe 40 degrees. 
   Not sure this is going to preserve your food much longer - maybe as much as twice as long, for some foods.  Certainly not going to freeze anything.
  I suppose this 'automatic chilling action' could help counter-act the warmth added when people visit the root cellar, or if it happened to be in the sun (which would definitely be goofy, if you're going to this much effort to chill it).

Your dry dirt is doing double-duty here, as both thermal mass and insulation.  Dry dirt conducts heat poorly; metal, stone, brick, or wet dirt are more effective at conducting heat, and sawdust or straw is more effective at insulating.

If you want to preserve a temperature colder than the ground, you might be better off building a well-insulated pit.  Then when you admit outside chill on cold days, you'd be better able to maintain a temperature difference once the outside warmed up again.  It's like a very big chest freezer, without power.  Holds cold air nicely, but don't open it too much or it'll all defrost within a day.

If you want to use some thermal mass to hold "cold" inside the insulated layer, ice or water is a great bet.  Dense dirt, rock, or brick with heat transfer pipes could also work.  Bringing in ice is going to chill that insulated pit much colder and faster.  It needs drainage to avoid flooding and spoiling the food.
  Piping cold air or cold water might be easier than ice-delivery; but less effective.
Water in that pipe would absorb about 4,000 times more extra calories of heat, as long as you're running it constantly when the weather is near freezing. 
Ice has a thermal mass about half that of water, _but_ it readily melts at those temperatures.  Even a tiny amount of ice melting absorbs a tremendous amount of heat.  So does water evaporating, if it has a place outside the cooler to evaporate _to_.

   Questions:
How do you chill things when you're camping?

Where are you thinking of building this theoretical ground-cooler?

References & Resources
To compare specific heat capacities: http://en.wikipedia.org/wiki/Specific_heat_capacity
scroll down for the chart.  There's also a chart of building materials, speficically mentioned as "useful for passive-solar design."

To compare the amount of energy it takes to freeze or boil water:
here's a reasonable site:
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/phase.html#c1
and try also "Energy involved in phase change of water"
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/phase.html#c3

These sites are using metric units.  We've been talking Fahrenheit so far. 
Ground temp in metric is roughly 15 C? 
So the amount of heat you'd need to absorb in order to freeze things (80 cal/g) is about 5 times as much as you'd need to chill them from 15 C (ground temp.) to 0 C.
   Heat capacity of air is .001 compared to water's 4 - so you'd need to warm up 4000 times as much air to chill each unit of watery foodstuffs.

I'm making the assumption here that most foods have a specific heat capacity similar to water - if they're dried-out already, then they don't need to be taking up space in your freezer.  Fat has lower conductivity, and a pretty high heat capacity.  Salt makes things freeze at lower temperatures, so salty foods like soup stock require temperatures well below 0 C.  (the Fahrenheit scale is based on a 0 that's close to the temperature of a mixture of salt and ice - that's why 0F is so far below freezing water temperature).
Here's a link with some specific heat capacities of other food and non-food substances: (ammonia, castor oil, sea water, etc):  seems to be between 1.5 and 4 on the scale that ranks water at 4.
http://www.engineeringtoolbox.com/specific-heat-fluids-d_151.html

Turns out cave temperatures (underground temps) aren't exactly uniform, either - 55 is pretty common, but it varies with location and local geology.  http://www.newton.dep.anl.gov/askasci/env99/env223.htm
It's the thermal mass of the cave that allows it to "average out" the heat and cold coming from above and below, and remain at relatively constant temperatures.  To chill a "cave" by allowing only cold air through it, you'd still be competing with the enormous thermal mass of all the other rock and dirt in contact with it.

Conclusion
In terms of return on effort - a root cellar works pretty good for maintaining constant temperatures, but it takes special effort to freeze things. 

Constant, relatively cool temperatures are ideal for certain foods: prevents condensation/drying cycles from temperature change, which leads to decay. 
If you can mimic winter ground temperatures, below the stored food's threshold for germination or enzyme activity, that might be all it takes.

If that's what you're looking for, it could work.

If you are looking for a way to quickly chill a basement during the desert night, in order to use it to air-condition the house above during the day - it could work great.

If you are looking for a free, no-moving-parts freezer for the Pacific Northwest, I don't think it's gonna happen that way.

-Erica
 
paul wheaton
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"it's cool, therefore it can freeze things."



I don't think I'm that bad. 

As I think more and more about this - my crazy ideas are turning out to have big problems.  Which is great that I find out here, rather than spend a bunch of money and time on experiments. 

I do, however, think that crazy ideas are the foundation of invention.

So .... as I ponder what a homesteader might do for a freezer without electricty or fancy chemicals ....  (mostly because it is fun to think of such things) ...  I keep coming back to the idea of having a 10x10x10 (1000 cubic feet) chamber surrounded by 20,000 cubic feet of dry dirt under a layer of insulation (wood duff).  I would guess that when brought to a temperature of less than 10 degrees, it would have a thermal inertia similar to 8,000 cubic feet of ice.  A series of tubes might help with the air exchange during really, really cold periods (below zero F) in, say, montana or eastern washington.    Granted, a lot of air would want to be moved through there for several days to "freeze" the dry soil enough.

Some of these ideas are shared here:  http://www.permies.com/permaculture-forums/1611_0/alternative-building/house-of-soil

So this would be kinda like an "ice well" but without ice.  A little like creating an artificial ice cave.  With a booster.

Just a nutty idea.  Of course, for it to work, there is a lot of "it depends" all over it. 


 
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Wood alcohol isn't a very fancy chemical.  It could be used in a heat-exchanger coil like the ammonia-filled one I proposed above, and the system assembled without welding.

Not as straightforward as an air duct, but it would take a lot less digging.
 
Erica Wisner
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paul wheaton wrote:
I don't think I'm that bad. 

As I think more and more about this - my crazy ideas are turning out to have big problems.  Which is great that I find out here, rather than spend a bunch of money and time on experiments. 

I do, however, think that crazy ideas are the foundation of invention.

So .... as I ponder what a homesteader might do for a freezer without electricty or fancy chemicals ....  (mostly because it is fun to think of such things) ...  I keep coming back to the idea of having a 10x10x10 (1000 cubic feet) chamber surrounded by 20,000 cubic feet of dry dirt under a layer of insulation (wood duff).   I would guess that when brought to a temperature of less than 10 degrees, it would have a thermal inertia similar to 8,000 cubic feet of ice.  A series of tubes might help with the air exchange during really, really cold periods (below zero F) in, say, montana or eastern washington.    Granted, a lot of air would want to be moved through there for several days to "freeze" the dry soil enough.

Some of these ideas are shared here:  http://www.permies.com/permaculture-forums/1611_0/alternative-building/house-of-soil

So this would be kinda like an "ice well" but without ice.   A little like creating an artificial ice cave.  With a booster.

Just a nutty idea.   Of course, for it to work, there is a lot of "it depends" all over it. 





No, you're not that bad.  I was trying to say, that I've heard a lot of wacky ideas from "the public" before. 

The dry ice thing, "so cold it's hot," is something I heard again and again.  Trying to get across to excited children, the difference between relative heat, and temperature; that "cold" is merely "contains less heat" and that when you touch it, your hand is donating a lot of heat to the cold object... that "boiling" does not mean "hot," regardless of the fact that we describe injuries from touching dry ice as a "burn" or frostbite; that different substances boil at radically different temperatures. 

I never did find a reliable way to help people understand.  Assumptions go deep, and our best hope was to produce a "discrepant event" that violated those assumptions, and hope that the audience would work it out in a more accurate way.  Sometimes, they just went to an even wackier set of assumptions.  Or enjoyed the discrepant event as "science magic," and left with their assumptions intact.

Without the corroborating detail, it's hard to judge your assumptions, or the amount of thought you've given to the physical laws involved.  So it's hard to give productive comments, without feeling the old dread of speaking into a brick wall.

Thanks for providing some numbers and a location.  If you get steep temperature drops in the areas where you're thinking of building this, it does make more sense.

Insulating around the whole thing, in addition to above it, would also make sense.
And big air-ducts makes more sense than small pipes.

I think the wood-alcohol idea is intrigueing.

I think homesteaders historically relied on easier options for food preservation, like drying food, or keeping hardy roots and fruits in cool storage without freezing.
Be interesting to see historic food preservation from the areas you mentioned.

But also historically, the guy with the ice-house was always popular.  Children in the Wilder stories remember the ice-house with an aura of wonder approaching magic.  So maybe it's worth the extra effort.

-Erica
 
Joel Hollingsworth
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paul wheaton wrote:Would this work on a spring too?  Like a windup toy?



I missed this question entirely when you first asked it!

No, a spring's elasticity works on a very different principle.  Entropy is actually what drives rubber back to its orgininal shape, and so it pulls harder as temperature increases.  Metals stretch by stretching each individual bond; entropy actually makes those bonds less direct, and so I think there would be, if anything, a tiny decline in elastic modulus, but no effect on the scale that rubber displays.
 
Joel Hollingsworth
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I'm reading your wofati article. 

I feel as though I'm turning on the light after stumbling through a furnished room, and saying, "Oh, that's a chair...that's a coffee table...that used to be a plate of lasagne: no wonder it was so slippery, and then so sharp."

The design you had in mind seemed like an obstacle to what I was trying to say, and that situation was sometimes confusing and messy.  A freaky-cheap freezer would, of course, not rely on refrigerant of any sort.

It occurs to me that water or brine in, for example, a section of inner tube, could plug and un-plug your wofati freezer by freezing and thawing.  None of the designs that come to mind yet are particularly compelling, but I'm certain a clever use of leverage and/or hydraulics could give a very simple and reliable system.  My imagination keeps suggesting an iris, and the rational side of me imagines a bat of insulation levering into place along the whole depth of the vent shaft...
 
paul wheaton
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Cool!  My article illuminates!

It occurs to me that water or brine in, for example, a section of inner tube, could plug and un-plug your wofati freezer by freezing and thawing.



And now I'm in the dark. 

I can read the words of what you are saying, but I am not making the connection as to what is going on.
 
                                  
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I've heard about old milk houses, stone floors and walls, with cold water constantly running over the floor.  We were inspired by the cold air we can feel walking up the hill to the spring. 

The spring water on our land is 47 degrees all year round.  We took an old fridge and plumbed it with 1/2" pex and water runs through it 24/7.  It keeps butter from melting in the summer and extends leftover shelf life - in the 60s in there at noon when it's 110 outside.  That sounds warm, but the summer of '08 I had nothing at all and it was a real challenge to keep things from spoiling quickly and melting everywhere.  I've learned a lot about what to buy and how long to expect it to last.  This time of year it's a pretty perfect fridge - usually right at 40.  We had a low of 11 the other night and it was 36 in the fridge. 

pics:

http://www.flickr.com/photos/fishermansdaughter/sets/72157621522225919/

We're in the process of building a large, completely buried concrete block cellar.  We plan to have the same 1/2" pex running through the concrete slab of that finished structure. 

So after 16 months living with out a real one....I feel that on a certain level refrigeration encourages consuming "un-fresh" food.  I'd rather eat something completely fresh or that has had fermentation both preserve and digest the food a bit for me (kefir is amazing!).  We aged some road kill deer this autumn when the daily temps were in the 60s...totally delicious 12 days later.  The only thing that we can't support with our set up that we like, but don't need, is half and half for morning beverages.  We buy a bag of ice a week for a small cooler in the summer, in the winter we fill it with snow.  Course, I'd rather have a cow. 

I'd be all for the discovery of an energy-free freezer, the science behind it is way over this lil noggin.  Modern homesteaders seem to be frequently very dependent on theirs.  We're trying to avoid one, but attempting commercial sales might change our minds. 
 
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The "magic" number is 40 degrees.  Above 40, bacteria are able to multiply rapidly and enzymes within the food are more able to decompose your stuff.  For each degree below 40, the shelf life of your cold foods is increased.  The closer you can get to 33, the longer it will last, but it won't last forever.

As with all heating and cooling, the less space and mass that needs to be cooled, the less energy is required.  Making changes in your need for refrigeration is an important step.  My brother, being the definition of Consumer, has the big fancy double door stainless steel fridge with ice and cold water in the door, and a digital temperature readout which he never looks at.  I think it even talks to you "Change Filter" or "Door Ajar."  Looking inside, does a person really need to keep 3 cases of soda cold at all times?

I have a Magic Chef 10 cuft fridge.  Its plenty big for my needs and operates on 1.7 amps of 110vAC.  This works well as I am limited to 15 amps for the whole house.  Its fairly energy efficient, but there are others on the market, Sunfrost for example,  which are considerably more energy miserly.  This particular model fits into my budget.  If powering a unit with solar PV, the choice is between more panels/batteries or efficiency of the appliance. 

In the absence of electricity, and in northerly climates, ice houses are practical.  There is lots of work involved in building the structure, but built well it should last for decades.  I looked at an icehouse built by an amish neighbor with typical stud frame construction, and a foot of sprayed cellulose insulation.  The fellow cut blocks of ice from a pond just down the road to fill the house every winter, it lasted through the year in USDA Zone 5, an hour west of Albany, NY, serving the needs of a family of 8.

In the absence of a harvestable body of water, ice can be produced with forms.  Inside the ice house, lumber can be used to form walls into which water can be added during freezing weather.  Open the doors to expose the water to freezing temperatures.  If outside the icehouse, anything that can hold water from which ice can be removed can serve as a form.  Rubber feed buckets work great in this regard.

The products being chilled fall into 4 major groups: meat, dairy, cut produce, processed goods.  Meat and dairy are considered "Hazardous Foods,"  in that they serve especially well as a breeding substrate for bacteria, and can readily drip onto other foods stored below resulting in cross contamination.  It is best to store these items on the lowest shelves with no other foods below.  Cut produce is the easiest product to store.  Wrapping, covering or containing them prevents flavor absorption and maintains moisture.  Processed goods include everything from leftovers to ketchup. 

Its late, just thought I'd ramble...
 
paul wheaton
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I just got an email from Diana Leaf Christian (a communities author that is mentioned here from time to time).  She mentions that she has a chest fridge and is gonna try to get rid of it to get a normal upright fridge so she doesn't have to dig for her food anymore. 

Fascinating!

 
                                  
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marinajade wrote:
I've heard about old milk houses, stone floors and walls, with cold water constantly running over the floor.  We were inspired by the cold air we can feel walking up the hill to the spring. 

The spring water on our land is 47 degrees all year round.  We took an old fridge and plumbed it with 1/2" pex and water runs through it 24/7.  It keeps butter from melting in the summer and extends leftover shelf life - in the 60s in there at noon when it's 110 outside.  That sounds warm, but the summer of '08 I had nothing at all and it was a real challenge to keep things from spoiling quickly and melting everywhere.  I've learned a lot about what to buy and how long to expect it to last.  This time of year it's a pretty perfect fridge - usually right at 40.  We had a low of 11 the other night and it was 36 in the fridge. 

pics:

http://www.flickr.com/photos/fishermansdaughter/sets/72157621522225919/

We're in the process of building a large, completely buried concrete block cellar.  We plan to have the same 1/2" pex running through the concrete slab of that finished structure. 

So after 16 months living with out a real one....I feel that on a certain level refrigeration encourages consuming "un-fresh" food.  I'd rather eat something completely fresh or that has had fermentation both preserve and digest the food a bit for me (kefir is amazing!).  We aged some road kill deer this autumn when the daily temps were in the 60s...totally delicious 12 days later.  The only thing that we can't support with our set up that we like, but don't need, is half and half for morning beverages.  We buy a bag of ice a week for a small cooler in the summer, in the winter we fill it with snow.  Course, I'd rather have a cow. 

I'd be all for the discovery of an energy-free freezer, the science behind it is way over this lil noggin.  Modern homesteaders seem to be frequently very dependent on theirs.  We're trying to avoid one, but attempting commercial sales might change our minds. 



I like the fridge Thanks for posting it and your experiences with it. That is a lot of help.
 
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paul wheaton wrote:And now I'm in the dark. 

I can read the words of what you are saying, but I am not making the connection as to what is going on.



Oh, oops. Here's a lot of text, but it might get my meaning across better.

One of the big features of a phase-change-driven heat exchanger for the underground freezer (like I had advocated) is that the phase change shuts down when you want it to, and starts up again when heat can be removed from the freezer.

A simple air shaft will exchange heat while open, even if that means warming up the freezer. It might have to be opened and closed manually to keep the system working.

My thought is that the air shaft might regulate itself. Imagine if really cold temperatures automatically caused some mechanical change, and opened up the air shaft to cool the freezer down. Once the air outside warmed up, that change could reverse itself, keeping outside warmth from entering the freezer.

That mechanical change might be an expansion of freezing water, the same effect that sometimes breaks pipes in an un-heated house. To make it reversible, the expansion could drive a piston, that pushes a lever and opens up some a hatch on the air shaft. Or the water could be in an old inner tube that's wedged between a moving part and a hard place. It might even be wedged in the hinge of the hatch cover, so that there is only one moving part. It can still be opened and closed manually, if the tube springs a leak.

The stuff that freezes could have salt (or glycerine, etc.) mixed in, to the point that it stays completely liquid unless the temperature is very low.
 
                                  
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I wonder how well a upright freezer would work with a remote thermostat?
Has anyone tried this?


I have been told that the old monitor top refrigerators only run 8 minutes a hour and are very efficient.
I wonder how many kWh they use in a day

I think Marinajade used one of these to make her cool box.
 
                    
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whitlock- There was a motor on top of ours at one point in its life, yes.  Long gone when we got it.  No idea about their electrical useage, but the rest of the thing is very well insulated and well made.  And heavy. 
 
                                  
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marinajade wrote:
whitlock- There was a motor on top of ours at one point in its life, yes.  Long gone when we got it.  No idea about their electrical useage, but the rest of the thing is very well insulated and well made.  And heavy. 



I thought so, what did you use to cover the top?
I bet that the old fridge is very well insulated. I'm sure better than a modern one.
What a perfect candidate for a cool box.

I might also try this on a larger scale-

http://www.communicationagents.com/chris/2004/04/14/cool_fridge_without_using_electricity.htm
 
paul wheaton
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Whitlock wrote:
I wonder how well a upright freezer would work with a remote thermostat?
Has anyone tried this?



Hundred of people have tried it and it works great.  That's what Diana is using (see above) - only she is seriously considering going back to an upright!
 
                          
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Susan Monroe wrote:
To tell the truth, the old method of cutting chunks of ice out of the lake and storing them in a straw-insulated shed still seems to be the simplest and most cost-effective way of cooling.

Of course, if you live in TX or SoCal or AZ, where you need cool worse than anywhere.... natural ice is probably hard to find.

Still, it just seems like there should be a way to do it with solar if someone who knows something could grab onto some kind of basic idea.

Sue



has anyone looked at a coolgardie safe no power no ice
 
                                  
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paul wheaton wrote:
Hundred of people have tried it and it works great.  That's what Diana is using (see above) - only she is seriously considering going back to an upright!



So the upright will save Kwh also but how many???
 
paul wheaton
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Bird wrote:
has anyone looked at a coolgardie safe no power no ice



Link?
 
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Whitlock wrote:
So the upright will save Kwh also but how many???



The upright uses about ten times more energy.  Diana thinks the chest style is a bigger hassle.
 
                          
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paul wheaton wrote:
Link?



http://en.wikipedia.org/wiki/Coolgardie_safe

also look at zeer pot link within the wikipedia link

and

http://aussiethings.biz/coolgardie-safe
 
Joel Hollingsworth
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Evaporative cooling can be great in very dry climates. One style you didn't mention is the vetiver root coolers they use in some parts of India.

Black mold can be a problem. They stop working when it gets humid, and of course the humidity they produce can make people less comfortable.

They also don't produce very low temperatures.
 
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Might be worth a look
www.selfsufficientish.com/fridge.htm
 
                          
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the pot in pot is called a ZEER POT system, and yes they do work well
 
                                  
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paul wheaton wrote:
The upright uses about ten times more energy.   Diana thinks the chest style is a bigger hassle.



What???

O.K.Paul the chest freezer with remote thermostat uses 100 watts a day and the upright freezer with the remote thermostat uses 1000??
Might as well use a regular fridge if thats the case insted of trying a upright freezer.
Are you sure this is the case???
 
                    
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Thanks for sharing the pot in a pot link! 

So 40 degrees may be the magic number for ultimate bacteria control, but I can tell you that temperatures not quite that cold are effective at keeping things from spoiling, especially if they're cultured.  Yogurt can live in a 50-60 degree environment just fine for a week to ten days, for instance.  I add a spoonful of miso to a pot of beans and that innoculation keeps them edible for a significantly longer period of time (three to four days as opposed to one or two). 

A part of my brain still thinks that artificially cold environments (no matter how they're achieved) probably are a major cause of our loss of the cultural knowledge of fermentation techniques.  I'm just not that interested in freezing all of our food.  I feel like loss of enzymes and the like might not be worth the extended storage time. 

And realistically, in rural areas, a lot of people (non-permies, which is the majority of rural dwellers) end up using lots of propane to keep their stuff cold.  If we didn't have the cultural need for cold storage, wouldn't we manage to keep our food safe to eat with different (low tech and no/low energy) methods? 

Cold storage has made the entire industrialized food chain possible.  Cold storage has made it possible for a person to honestly say "I don't cook" because their food is prepared at a distant location and designed for long term (indefinite in lots of cases) cold storage.  A bunch of the worst examples of processed food I can think of are frozen. 

I know homesteaders use their freezers quite differently than what I just described, but the "need" for a freezer, I think, is more of a need for convenience.  We're probably going to get a chest freezer eventually, but I recognize it as an extra and do not see it as a necessity.  I doubt we'll be able to avoid purchasing one when we sell food to the public. 

Whitlock -- Our cool box just has a folded cardboard box across the top and a polyester blanket stuffed on top of that...not our ultimate design plan.  We will someday make a wooden "hat" for it that's stuffed with about 12'' of wool.  I think it will maintain a range of 50s in the middle of a summer day after we add that (the way it is now, in the morning the temp is around 50, and it climes to 65 by mid afternoon[when it's over 100 outside]).  The reason we were given it in the first place is our neighbors were concerned about the asbestos insulation....but we decided it's contained in the walls of the thing well enough to not pose a problem, once kept dry and clean.  We puzzled as to how the asbestos was made any to be less hazardous with the fridge continually laying on the side of the road.....
 
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so, I'm coming to this conversation a bit late.  like Dave mentioned early in the thread, I've also heard stories of ice manufacturing involving water dripping down cooling towers placed in the wind.  the story I recall was about ice made in Texas, but I'm having a deuce of a time finding any reference to it on these here internets.  closest I found was this quote:

A high cooling structure stood on the roof of the squarish building at the east end. Water once dripped down through layers of planks as part of ice manufacturing.



from this article.  very cryptic, that.  I suspect the cooling towers were only the first step in cooling the water and the rest was mechanical.

anyhow, the discussion also reminded me of Persian qanats.  combined with windcatchers, they have been used for quite some time to keep temperatures rather more reasonable in very hot, dry places.  requires a considerable outlay of labor, but it's so very clever and effective.

for those of us in less than arid places, I wonder if a desiccant like CaCl  could be used to increase the effectiveness of evaporative cooling techniques such as a zeer.  after use the desiccant could be dried out in the normal course of cooking or heating and reused.  might be more trouble than it's worth, but perhaps interesting to play around with.
 
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Whitlock wrote:
What???

O.K.Paul the chest freezer with remote thermostat uses 100 watts a day and the upright freezer with the remote thermostat uses 1000??
Might as well use a regular fridge if thats the case insted of trying a upright freezer.
Are you sure this is the case???



A standard, upright fridge uses ten times more energy than a chest style fridge. 

 
                                  
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paul wheaton wrote:
A standard, upright fridge uses ten times more energy than a chest style fridge. 




Is this the case with the remote thermostat.
Sorry for dragging this on I'm just not sure you are answering my question ops:

 
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Whitlock wrote:
Is this the case with the remote thermostat.
Sorry for dragging this on I'm just not sure you are answering my question ops:



I don't know what you mean by "remote thermostat".

I'm talking about converting a chest freezer to a refrigerator using a thermostat that will shut off the freezer when it gets cold enough.
 
                                  
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paul wheaton wrote:
I don't know what you mean by "remote thermostat".

I'm talking about converting a chest freezer to a refrigerator using a thermostat that will shut off the freezer when it gets cold enough.



A remote thermostat is what you use to convert a chest freezer into a fridge.It plugs into the wall and your freezer plugs into it.
How about I call it a external thermostat.

Here is a picture-

http://mtbest.net/chest_fridge.html

Now my is what kind of Kwh's would I get if I used this on a upright freezer. Instead of a chest freezer.
 
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Whitlock wrote:
Now my is what kind of Kwh's would I get if I used this on a upright freezer. Instead of a chest freezer.



Every time you open the upright you dump all the cold air out. It becomes just like an upright fridge.
 
                                  
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ronie wrote:
Every time you open the upright you dump all the cold air out. It becomes just like an upright fridge.



Not with a box in the bottom of it. I made a stainless steal box for the freezer at the barn and you can see the cold air enter it instead of pouring out the bottom on to the floor.
 
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Whitlock wrote:
Not with a box in the bottom of it. I made a stainless steal box for the freezer at the barn and you can see the cold air enter it instead of pouring out the bottom on to the floor.



OK, then it becomes like a fridge with a box in it. Why go through all the troubles of converting an upright freezer into a fridge? Just put a box in the bottom of a fridge. 

For those ,who have so much 'stuff' in their freezer/fridge , that they have to dig through other stuff to find what they want  -  you have too much stuff.
 
                                  
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The box is only 12 inches deep and it is on drawer runners. It fits under the lowest rack in the freezer.
 
                          
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A few years ago I took a cob cottage workshop or natural building or something.
The teacher who calls himself Donkey had designed and begun building a solar fridge.
the insulation was, of course, cob.
The cold was provided by evaporation running across aluminum being the bottoms of beer cans facing the air cooling chamber. - He explained that there is more cooling from damp aluminum, or something like that.

The air comes into a long fat tube built into the side of the hill and enters the cooling chamber.
It continues across a wet cloth which is evaporating from a drip and continues past the aluminum cans and into the shelves area where food is kept cold.
All this is possible because there is a tall not-smoke stack chimney which is painted black and exposed to the best sun of the place creating a constant strong draft on sunny days.

He told us that even though it was only partially made, his wife made him close the area off because it was too cold near it.

It is a brilliant design and I hope someone who needs refrigeration soon can make one and let us know.

Thanks to Donkey!

I have a picture I made a while ago, so here it is.

jeanna
Donkey-s-Solar-Fridge.gif
[Thumbnail for Donkey-s-Solar-Fridge.gif]
 
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Has anyone though of using coolers and then storing them in cold rooms or outside.  I recently read an article in Countyside about not having a root cellar and instead using coolers and then placing them in a unheated room or outside depending on the weather.  The woman in the article had used them to store her apples and carrots in during the winter. 

I wonder what other uses could come out of them?
 
Cob is sand, clay and sometimes straw. This tiny ad is made of cob:
Hope in a World of Crisis - Water Cycle Restoration
https://permies.com/t/118080/Hope-World-Crisis-Water-Cycle
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