Post by woodyz on Jul 3, 2012 17:55:18 GMT -7
I posted some of this on that old site. A recent conversation got me to look up and update what I had on the subject.
My son is a insulin dependent diabetic so keeping his insulin supply cool becomes a problem from the first day of no electricity.
Our defense lines became; keeping the electric on, having a generator, then having generators that used tri-fuels.
I knew in a pinch we could use solar or evaporative cooling, like the ZEER Pot to keep food up to twenty days.
www.appropedia.org/Zeer_pot_refrigeration_(design)
The Zeer Pot works through evaporation. As the moisture in the media evaporates, it pulls heat from the innermost and cools the internal temperature of your “refrigerator.”This device works best in drier climates. In humid areas, it may be less effective.
We had proven it out to maintain insulin temperature below 45 degrees. I also found and old ice cream freezer works very well and will allow you to do a rapid cool down using the crank used when making the ice cream. just cut a few additional holes in the wooden bucket and screen over them to get a good air flow and keep your cooling media from falling out.
For the media some just use dirt or sand, any insulating material, including foam/cotton from an old mattress.but I have found saw dust mixed with sand works very well. You just need something to absorb and hold the water, but release by evaporation. The evaporation of the water in the media pulls the heat from the warmer inside pot away from and out of the outside pot.
It’s best to use water that is also pure enough to drink, since the clay walls of the pot are porous. However, if you wish to use water that is not potable for your Zeer Pot, you can glaze the INSIDE of the smaller pot.
Then I found an article this last summer on an improvement to the clay pots and built it to test.
www.gizmodo.com.au/2010/10/23-year-olds-solar-powered-fridge-earns-prestigious-award/
It also proved out.
Then I wanted to find something we could use that would be more portable if we needed to stay moving. I used small ice chests, thermos jugs, etc.
We finally settled on a 1” piece of PVC with another tube inside. We started with another smaller diameter piece of PVC but found we needed a material difference between the inside and outside containers to improve air flow. So the new cooler has a metal tube as an inside container. The outside PVC is just filled with drill holes and the space between the two containers is saw dust.
Next was to reverse the effect for winter. In this case I filled the inter container with hot water and stored the insulin in the outside container. This worked but not as good as I wanted it to.
But changing the inside liquid to antifreeze worked much better. The heat disapates from the water more quickly than the antifreeze. Making the inter container removable so it can be heated in hot water also made for a more efficient system.
My son is a insulin dependent diabetic so keeping his insulin supply cool becomes a problem from the first day of no electricity.
Our defense lines became; keeping the electric on, having a generator, then having generators that used tri-fuels.
I knew in a pinch we could use solar or evaporative cooling, like the ZEER Pot to keep food up to twenty days.
www.appropedia.org/Zeer_pot_refrigeration_(design)
The Zeer Pot works through evaporation. As the moisture in the media evaporates, it pulls heat from the innermost and cools the internal temperature of your “refrigerator.”This device works best in drier climates. In humid areas, it may be less effective.
We had proven it out to maintain insulin temperature below 45 degrees. I also found and old ice cream freezer works very well and will allow you to do a rapid cool down using the crank used when making the ice cream. just cut a few additional holes in the wooden bucket and screen over them to get a good air flow and keep your cooling media from falling out.
For the media some just use dirt or sand, any insulating material, including foam/cotton from an old mattress.but I have found saw dust mixed with sand works very well. You just need something to absorb and hold the water, but release by evaporation. The evaporation of the water in the media pulls the heat from the warmer inside pot away from and out of the outside pot.
It’s best to use water that is also pure enough to drink, since the clay walls of the pot are porous. However, if you wish to use water that is not potable for your Zeer Pot, you can glaze the INSIDE of the smaller pot.
Then I found an article this last summer on an improvement to the clay pots and built it to test.
www.gizmodo.com.au/2010/10/23-year-olds-solar-powered-fridge-earns-prestigious-award/
It also proved out.
Then I wanted to find something we could use that would be more portable if we needed to stay moving. I used small ice chests, thermos jugs, etc.
We finally settled on a 1” piece of PVC with another tube inside. We started with another smaller diameter piece of PVC but found we needed a material difference between the inside and outside containers to improve air flow. So the new cooler has a metal tube as an inside container. The outside PVC is just filled with drill holes and the space between the two containers is saw dust.
Next was to reverse the effect for winter. In this case I filled the inter container with hot water and stored the insulin in the outside container. This worked but not as good as I wanted it to.
But changing the inside liquid to antifreeze worked much better. The heat disapates from the water more quickly than the antifreeze. Making the inter container removable so it can be heated in hot water also made for a more efficient system.