Refrigeration without electricity

[picaro]

Here's how it works. You take a smaller pot and put it inside a larger pot. Fill the space in between them with wet sand, and cover the top with a wet cloth. When the water evaporates, it pulls the heat out with it, making the inside cold. It's a natural, cheap, easy-to-make refrigerator.

http://www.newmediaexplorer.org/chris/2004/04/14/cool_fridge_without_using_electricity.htm

[Kat Kanning]

Way cool

[dalebert]

I remembered the basic principle but was reminded of the exact numbers recently in an FTL thread.

It takes one calorie of heat to raise the temperature of one gram of water by one degree. In fact, that's where the calorie measurement is derived. However, it takes 540 calories to transition a gram of water from a liquid to a gas. That's presumably how much heat is removed for every gram of water lost to evaporation.

This is how air conditioners and refrigeration work only they use freon which behaves similarly but I don't know the exact numbers. Freon evaporates at a very low temperature and absorbs a tremendous amount of heat in the process. Compressors force it back to a liquid state which forces the heat back out of it and that heat is blown outside. That's why hot air is blowing out the back. It's also why your refrigerator is generating a lot of heat. It's not necessarily a bad thing in the winter.

A lot of you prolly know this already but I just think it's fascinating and thought I would share it with the less enlightened. 

I bet this is where the myth comes from that if you bury beer in sand and pour gasoline and set it on fire, it will cool the beer quickly. It's a myth, as I said, but I bet the origins come from this idea and someone got it in their head they could speed up the process with gasoline. Of course, burning gasoline is generating heat, and quite a lot of it, where as this idea is based on transferring existing heat away. It's not the same process at all.

[Puke]

My simple, easy to purchase fridge uses electricity. 

[Beth221]

9 months out of the year you can store your beer outside, where temps are colder than your normal refrigeration system, and winter runs on no electricity! 

[Jim Johnson]

That guy won $100,000 for reinventing a cavalry blanket cantine.   
Where in the hell was I...

[Puke]

If it wasn't for the idiot UN and greeneys Africa probably would have electricity.

[J’raxis 270145]

If the West hadn't been sending so much "aid" to Africa, they'd have probably fixed all their (caused by colonialism) problems by now...

[MaineShark]

If it wasn't for the idiot UN and greeneys Africa probably would have electricity.

Or not need (much of) it.

I recall a water pump that was designed by a research group for rural communities.  It was extremely efficient (hooked to a see-saw, so children playing pumped the village's water), and repairable with common tools and materials.

The UN folks came in, ripped out the pumps, installed electric pumps and diesel generators, then left.  Now the villages have pumps that won't run without expensive fuel, and which wear out and cannot be repaired without expensive parts and tools.

Joe

[Jim Johnson]

If it wasn't for the idiot UN and greeneys Africa probably would have electricity.

Or not need (much of) it.

I recall a water pump that was designed by a research group for rural communities.  It was extremely efficient (hooked to a see-saw, so children playing pumped the village's water), and repairable with common tools and materials.

The UN folks came in, ripped out the pumps, installed electric pumps and diesel generators, then left.  Now the villages have pumps that won't run without expensive fuel, and which wear out and cannot be repaired without expensive parts and tools.

Joe

...hooked to a childs see-saw and extremely efficient... 

...folks came in,... installed electric pumps and diesel generators.... fuck'n bastards...   

[ReverendRyan]

I've seen plans before for essentially a double-walled shed with a gap of about 2 or 3 feet between the inner and outer wall. The idea was you shovel snow into the gap throughout the winter and it compresses itself into a block of ice. It cools and insulates throughout the warm months. It's amazing how long it can take a large chunk of ice to melt. Anyone seen plans for one of these?

[Jim Johnson]

I've seen plans before for essentially a double-walled shed with a gap of about 2 or 3 feet between the inner and outer wall. The idea was you shovel snow into the gap throughout the winter and it compresses itself into a block of ice. It cools and insulates throughout the warm months. It's amazing how long it can take a large chunk of ice to melt. Anyone seen plans for one of these?

Plans?

In 1800, when someone wanted to know how to build a cooler building, he would ask an older person with experience.
Old person would say something like, ya build a set of tight walls inside another set of walls.  Ya put straw bails aga'n the outside of the outer walls.  Ya put snow between the two sets of walls. 
When the weather gets warm you put straw on top of the snow.  When it doesn't snow you buy ice from Canada.  They'll sell it to you by the wagon load.

Well of course you put a roof on the center walls ya dang fool.

[ReverendRyan]

What I meant is I'd seen it as a prefab.

[Jim Johnson]

They already cut the boards and bailed the straw.  Ya want them to shovel the damn snow too?

[Lloyd Danforth]

Ice houses were often doubled walled with sawdust between the walls.