Talk:Pot-in-pot refrigerator

First used by the Egyptians?

I heard it said that this was first used by the Egyptians - anyone have info on this? --Singkong2005 —The preceding unsigned comment was added by 129.94.6.28 (talk) 04:28, 15 December 2006 (UTC).

My parents used something similar with a bucket covered by a cloth while camping (before 1995...), so this is not a new idea. —Preceding unsigned comment added by 85.210.72.126 (talk) 21:55, 28 August 2008 (UTC)

• I believe that the Ancient Romans used a similar technology. They placed the food inside stoppered glazed pot (i.e. waterproof), and then placed that pot inside larger unglazed pot. The gap between the pots was then filled with water, the larget pot stoppered, and placed in a shaded, windy location. The water would diffuse through the unglazed pot, and evaporate as it reached the surface, thus cooling the food. CS Miller (talk) 10:22, 17 May 2009 (UTC)

technical details?

how cold does it get? how long does it take for the food to cool? Does it actually stop most bacterial growth? —Preceding unsigned comment added by 66.75.5.159 (talk) 07:27, 3 April 2008 (UTC)

• You can read about it at the Rolex Award webpage for Mohammed Bah Abbas. It said that the system "maintained temperature below 20°C" and "up to 14 degrees cooler than the surrounding environment". Roger Hui (talk) 21:05, 3 April 2008 (UTC)

"maintained temperature below 20°C" is for a room-sized chamber with brick walls at the Punjab Agricultural University in Ludhiana — cmɢʟee୯ ͡° ̮د ͡° ੭ 18:01, 18 July 2013 (UTC)

Theoretically devices like this can cool arbitrarily close to the dew point, which is what makes them effective in the dry desert climates. This also means that, apart from the SW US, Spain and Australia, they're quite useless in western countries. Right now the temperature in my room is 26⁰C, dew point is 22⁰C, so it would cool to about 23⁰C. I wouldn't buy a refrigerator like that, even if it costed me only €1. Which brings me to the point, the sentence about potential use in western countries can be removed. It's hardly encyclopedic anyway. If somebody thinks it is, just reinstate. PiusImpavidus (talk) 16:01, 19 June 2013 (UTC)

chilly bins

This system would appear to be ideal for chilly bins/coolers/ice boxes. A link from this article to such a product would be useful. I'll search for a link now 121.73.7.84 (talk) 12:11, 21 November 2010 (UTC)

Additional References

I found quite a lot that would be useful to add to this article, but also quite a lot that I can't verify. Can someone please take a look at these links and the references they cite (as applicable) and see if there's anything we can incorporate? Sutematsu (talk) 22:21, 24 December 2010 (UTC)

• Appropedia Zeer Pot Refrigeration
• Pot-in-pot: Refrigeration for the Poor

• This porous stone(?) fridge Seems to be a largely identical technology which was commercially available in Europe in the 1960s.

It was never very effective in Scotland or Wales, for reasons that other parts of the article make clear

Hieroglyphics

Before I added cites and additional info, I saw that the article mentioned that this type of refrigeration had been mentioned in hieroglyphics. However, I couldn't find anything to support this, and removed the reference. If someone else knows where we can get a reference to this, please add it. Sutematsu (talk) 22:25, 24 December 2010 (UTC)

Citation Needed in Construction Section

"Evaporative coolers tend to perform poorly or not at all in climates with high ambient humidity." This is basic science. As humidity increases, evaporation decreases up to the point of 100% relative humidity where it stops. Less or no evaporation means less or no evaporative cooling.

"If there is an impermeable separation layer between the food and the porous pots, undrinkable water such as seawater can be used to drive the cooling process, without contaminating the food. This is useful in arid locations near the ocean where drinkable water is a limited commodity, and can be accomplished by using a pot that is glazed on the inner wall where the food is stored." This is basic logic. A physical barrier protects the food from being contaminated with non-potable water.

"Extended operation is possible if the pots are able to draw water from a storage container, such as an inverted airtight jar, or if the pots are placed in a shallow pool of water." Again basic logic. The jar or dish acts as a reservoir that replenishes the moisture in the sand as it evaporates through the outer wall of the outer pot.

These three statements seem clear and not needing of additional citation beyond basic science and logic. — Preceding unsigned comment added by 68.183.172.140 (talk) 19:02, 1 August 2011 (UTC)

Agreed on points one and three, and the "citation needed" tags have been removed from those. However, not as sure about point number two. Are all glazes necessarily waterproof? Sutematsu (talk) 22:10, 19 August 2011 (UTC)

Realized that I could get around the "are all glazes waterproof?" issue with a small rewrite in the text. *facepalm* Edited and citation tag removed. Sutematsu (talk)

proposed merger 2012

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section.

solar powered refrigerator+pot-in-pot refrigerator

• oppose The solar powered refrigerator article is talking about modern compression based refrigerators, which happen to generate electricity via solar power. That is not an appropriate target for a merge (although a see also may certainly apply) Gaijin42 (talk) 15:42, 3 February 2012 (UTC)
• Oppose. Each article discusses a different, and largely unrelated, technology. The Pot-in-pot refrigerator article does not even mention the word "solar". Johnfos (talk) 20:00, 3 February 2012 (UTC)

Have either of you actually read solar-powered refrigerator? The only parts which are referenced refer to the pot-in-pot refrigerator, specifically Emily Cummins's eco-fridge variant, and multiple sources refer to this as a "solar-powered refrigerator". Chris Cunningham (user:thumperward) (talk) 07:58, 6 February 2012 (UTC)

Absolutely. Yes, pot in pot is solar powered, just like a clothesline is. But the other article is talking about using standard freon/compression refrigeration technologies, which happened to be powered by the sun. That is a completely different concept. Pot in pot can be created by anyone with mud. solar power refrigerators require advanced manufacturing capabilities. Gaijin42 (talk) 17:43, 6 February 2012 (UTC)

PiPR is not really "solar powered" in any direct sense. What it needs is ambient heat from the local environment, and very low humidity. A common condition of arid/desert environments.

Solar power usually involves direct photonic radiation absorption, such as through a photovoltaic panel or thermal absorption tank. PiPR is indirect due to water evaporation drawing heat off of the pot. You would want to shield the pot from direct sun exposure as that would likely cause more heating than evaporative cooling.

PiPR is generally likely to be an indoor technology out of the sun, such as inside a tent or other shelter, but needing very low ambient humidity to drive the evaporation process.

A building-cooling method that involves evaporation and air ventilation is known as a swamp cooler. DMahalko (talk) 04:46, 7 February 2012 (UTC)

This is all very nice, but it's irrelevant to the matter of the merge. Right now, solar-powered refrigerator is basically just a wad of personal opinion on theoretical or obscure conventional electric fridges which use solar power (which doesn't warrant inclusion at all) coupled with discussion of the eco-fridge, which is a PiPR. As such, the most logical way to proceed would be to merge said article here so that the sources (which really discuss the PiPR) are included in the right article, while we do not lend undue weight to alleged high-tech devices which have had no established impact on the world. A merge makes sense because even if it is not "solar powered" in the conventional sense, numerous reliable sources have referred to the PiPR as a "solar-powered refrigerator". Chris Cunningham (user:thumperward) (talk) 04:53, 9 February 2012 (UTC)

Gaijin42 and DMahalko make some good points. Pot in pot (PiPR) can be created by anyone with mud, whereas solar power refrigerators require advanced manufacturing capabilities. They are completely different concepts. PiPR is not "solar powered" in any direct sense. I still oppose the merge, and suggest that all the PiPR material be put in one article, and all the solar powered refrigerators material in the other. Johnfos (talk) 05:08, 9 February 2012 (UTC)

Well, there's still work to be done here. I'll be moving all of the material currently in solar-powered refrigerator which deals with the eco-fridge to pot-in-pot refrigerator. At the same time, I'll be removing the unsourced essay-type material from solar-powered refrigerator and readding a hatnote pointing to pot-in-pot refrigerator due to the references which refer to the eco-fridge as a solar-powered refrigerator. Chris Cunningham (user:thumperward) (talk) 06:59, 9 February 2012 (UTC)

It doesn't look like you have consensus to do the merge.

The PiPR is "dry air powered", not solar powered. Don't need sunlight to have dry air to operate the cooling process.

Besides there can be purely solar powered thermally operated refrigerators using modern technology. Take a look at ammonia refrigeration.. Absorption refrigerator. Those can certainly be solar powered to drive the boiling chamber. They are also commonly powered by propane in recreational vehicles.

And it is fair to discuss solar powered electric refrigeration, with photovoltaic panels and batteries in the other article. Likely would not be a huge 1000 watt auto-defroster fridge like in an average American home though.

DMahalko (talk) 06:46, 10 February 2012 (UTC)

Err, yes, that's why I removed the merge tag. I'll continue to work on this, as like every other sustainable development topic on Wikipedia our coverage here is still a complete mess. Chris Cunningham (user:thumperward) (talk) 09:10, 10 February 2012 (UTC)

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The above discussion is closed. Please do not modify it. Subsequent comments should be made in a new section.

No picture?

How in the world does this entry have no picture? — Preceding unsigned comment added by 78.34.160.44 (talk) 09:04, 21 August 2012 (UTC)

Here is a picture link : https://www.facebook.com/greenrenaissance/photos/a.430117437006046.105279.120085081342618/834875839863535/?type=1 — Preceding unsigned comment added by 78.21.89.22 (talk) 23:01, 13 June 2014 (UTC)

Unfortunately we can't just appropriate pictures from someone else's website without permission. That would be a copyright violation. Richerman (talk) 16:59, 14 June 2014 (UTC)

Pot-in-Pot Preservation Cooling System

Is the "Pot-in-Pot Preservation Cooling System" technically any different? Is it not simply that Nigerians were generally unaware of the underlying technology - despite it having been used through Europe and North America for thousands of years.Royalcourtier (talk) 20:12, 6 February 2015 (UTC)

The history of Zeer is in this article, and Zeer redirects here. Gaijin42 (talk) 20:15, 6 February 2015 (UTC)

Commercial marketing

The last section reads like a commercial for the Nigerian pot-in-pot: "Pot-in-pot refrigeration has had multiple positive impacts on the population that uses them beyond the simple ability to keep food fresh for longer periods of time and decreasing instances of food-related disease", etc.Royalcourtier (talk) 20:17, 6 February 2015 (UTC)

Commercial evaporative coolers ?

Perhaps we can mention some discontinued popular evaporative coolers like the Osokool (see here). The top of this cooler was made of chalk and had an indentation into it in which you poured water. The evaporative effect of the wet chalk caused a temperature drop inside the box.

Also, perhaps we best mention Emily Cummins' evaporative cooler (see here and here)

KVDP (talk) 11:28, 14 September 2017 (UTC)

Medicine and vaccine storage

Reading the article, I see that the Effectiveness section says that Non- electric evaporative cooling devices – such as ECCs and clay pot coolers – are not suitable for items that require sustained temperatures below 20 °C (medicine, meat, and dairy products), but at the same time, in the following Impact section it says that among the benefits of the technology there is The ability to store vaccines and medicines that would otherwise be unavailable in areas without refrigeration facilities. I wanted to let other editors know, if there were still following the article, and have added the respective inline tags. NoonIcarus (talk) 18:50, 27 January 2023 (UTC)