portable solar powered condensation fridge

[unpossibles]

http://www.dailymail.co.uk/sciencetech/article-1108343/Amazing-solar-powered-fridge-invented-British-student-potting-shed-helps-poverty-stricken-Africans.html

It's the kind of simple yet brilliant invention that would have the tycoons of Dragons' Den salivating with excitement.

Not only is the fridge solar powered, it can also be built from household materials - making it ideal for the Third World.
...
Her 'sustainable' fridge works through evaporation and can be used to keep perishable goods such as milk and meat cool for days.
Without using any power, temperatures stay at around 6c.

The fridge comprises two cylinders - one inside the other. The inner cylinder is made from metal but the outer cylinder can be made from anything to hand, including wood and plastic.
...

[RandomThoughts]

1. Invented by a 21 year old student !

That is awesome!!!

Emily Cummins, 21, came up with the idea while working on a school project in her grandfather's potting shed. The fridge is now improving the lives of thousands of poverty-stricken Africans.




But still things to overcome
She had been refused a place on an engineering course because, to her dismay, she didn't have the correct qualifications.

However
Last year she met the Queen at Buckingham Palace after being invited to a prestigious women in business event.

[Ghost Dog]

2. Excellent.

Let her get on an Environmental Sciences course.

Good-looking potting shed, also.

[drm604]

3. This is good but only if you have a steady supply of water to keep the sand wet.

In many third world areas, water isn't plentiful enough to use like this.

It might be better if the heat from the sun was used to drive some kind of closed cycle of evaporation and condensation, or maybe solar cells could be used to drive an electric compressor or a peltier device.

[Warpy]

4. Right, and low relative humidity

It's not going to work all that well on a foggy beach, for instance.

The sand can be soaked with waste water, though, instead of potable water.

The beauty of this is its total simplicity, the lack of moving parts or chemicals. All you need is a bucket and a water source, keep soaking the puppy down every few hours.

I'm not sure I'd cook meat stored in it for several days rare, but it would do a great job with veggies and dairy.

[drm604]

5. You could use waste water but

you'd need to be very careful to keep it completely separated from the food. Plus there are dangers in handling waste water, especially in third world countries.

I just wonder if there isn't something else, that might not be so simple to build but could be provided by relief agencies, that would be sturdy, reliable, have few or no moving parts, use no power other than sunlight (or possibly wind) and not require constant wetting down.

[tinrobot]

6. The evaporating water has to go somewhere

Maybe add some complexity to the device to recover the evaporating moisture.

[drm604]

7. You would have to somehow condense the recovered moisture.

That would entail either cooling it or compressing it. If we compress it then we're talking about something similar to the refrigerator you have in your kitchen, which is what we're trying to avoid.

If we're not concerned about portability then maybe we could condense it by cooling it by piping it underground somehow. We don't have to get it down to refrigeration temperatures. It just has to be cool enough to become liquid. Of course, pushing water vapor down and pulling liquid water back up requires pumping it which takes more energy than is needed for simple evaporation of water. I suppose a wind driven pump could achieve this but if we're going to do that then we might as well just use it to drive a standard refrigeration compressor, although taking advantage of the cooler underground temperatures presumably would save some energy.

None of that gives us a device that is portable, easy to make, and easy to use.

[Xithras]

9. What you need already exists. It's called an absorption refrigerator.

Though it fails on the "easy to make" front, absorption refrigerators require only HEAT to cool the contents inside. There are already absorption refrigeration systems that use lensed solar heat to drive the process, and a small well insulated or partially buried unit can be run on this alone. Larger units in industrialized countries are typically powered by propane, but small units in primitive areas could be augmented by anything from wood to cow dung if solar power is insufficient.

If you've ever rented an RV, you've seen one of these things in action. Basically, instead of water (which has a high boiling point) they'll use something like ammonia in a closed system since it boils at a much lower temperature. The ammonia evaporates, cooling the chamber, and mixes with hydrogen. That mix then attatches itself to water. If the water is heated, the pure ammonia will distill back out and can be reused again. The great thing about the system is that it has no moving parts and has nothing to wear out. If the system is kept sealed and a little heat is applied, it just works.

BTW, these were actually quite common in American homes in the early 20th century, but lost favor to compressor refrigerators because these don't get quite as cold. An evaporative freezer might take a day to turn a tray of water into ice, while a compressor one can do it in only an hour or two. Still, the technology is widely used and is uber-reliable. The only problem is that it tends to be very expensive for people in poorer parts of the world because it's not something that can be built without specialized equipment.

[drm604]

10. I guess what it comes down to is that you either need high tech or a good water supply.

It looks like you need one or the other.

[jberryhill]

13. No, you need this guy

Evaporative cooling pots have a long history.

[drm604]

19. Yes, but he needs a supply of water to keep it moist.

Which is what I said.

[here_is_to_hope]

14. We have two of these units made for home use

Bought them through Lehmans and they work great. One is positioned to slide through a seasonal opening in our kitchen wall. In the winter, I position it half in, half out of the house. It comes on but once a day for 6 months at a time.
They were not cheap but in the long run, it was cheaper than adding extra solar capacity and storage to our power system to be able to use a regular power sucking fridge.

[GreenPartyVoter]

15. So add a water extractor in there somewhere. Grab it from the air and send it to the fridge?

[drm604]

20. Which requires some kind of pump or compressor,

and therefore requires an external energy source.

[GreenPartyVoter]

22. Solar panels might work, but you'd need enough juice to store in a battery big

enough to get through the nights and cloudier days. :(

[Xithras]

8. Bzzt. Ripoff Alert! She stole this design! Seriously!

It's called a Zeer and was invented by a guy in Nigeria in the mid-90's as a way to provide refrigeration to people in primitive areas without electricity. The original Zeer design is even simpler and can be made of all natural materials such as clay pots, though metal ones are also used.

The Zeer won a Rolex Design award and was all over the news about 7 or 8 years ago, and the inventor has been using the award money to build and distribute these things to poor people all over Africa. Interestingly, if you read the article, you'll see that she claims to have "perfected" the design while she was in Africa. My guess was that she saw a Zeer in action and copied it.

So what we have here is a young European woman who stole a design from an black African inventor, prettied it up for mass marketing, and is now passing it off as her own. I TRULY hope she gets her ass sued off and gets publicly humiliated for this.

[drm604]

11. I don't like to accuse without evidence but it does seem likely. n/t

[jberryhill]

12. Evaporative cooling is common enough a concept that it doesn't have to be conscious

Having worked in patents for a long time, I can tell you it's very common for people to invent things that have been invented before (which is why US law uses the phrase "first to invent", since "invent" does not imply temporal priority).

[napoleon_in_rags]

21. Man, this is why I hate intellectual property concepts.

What actually matters is that this idea is propagated wherever in the world it helps people. (BTW I'll bet putting two pots inside each other with wet sand is an older african traditional than history) These people do us a service by working on and putting forth these ideas, but the idea of owning and stealing these ideas seems counterproductive to me.

[Xithras]

23. I agree with you, I just don't like her claim.

What pisses me off is the smug little British girl getting global accolades for developing something to help those "poor powerless Africans" when she neither invented it nor played any serious part in spreading the technology across Africa. It has shades of the old "white man saves the primitive savage" mindset that dominated European relations with the rest of the world for centuries.

FWIW, the guy who actually DID invent the Zeer has been training people and giving the idea away for no charge, and only makes money on the prefab ones that he sells for a few bucks (creating employment for people in a region with few jobs). He (and I) would agree with your concept that inventions like this one should be distributed as widely as possible. I'm simply saying that the credit belongs where it is due, and that's NOT with a well-to-do British teenager who was experimenting in grampa's pot shed.

[napoleon_in_rags]

24. Yeah, good point. Maybe we should look at what we give credit for.

We tend to celebrate ideas and inventions rather than their useful deployment. Maybe that should change, instead of celebrating ideas we should celebrate ideas which are deployed for good. That way credit is truly given to whoever is making the positive changes, in this case the African guy.

[madokie]

16. That could be incorporated in homes too

Have a cool wall in some rooms. a person could actually let the moisture that would condense to keep some house plants watered. All the more for making the environment that we spend so much of our time in healthier.

[IDemo]

17. A simple solar cooker that works as a cooler at night time

http://www.solarcooking.org/PLANS/funnel.htm

How to Use the Solar Funnel as a Refrigerator/Cooler

A university student (Jamie Winterton) and I were the first to demonstrate that the BYU Solar Funnel Cooker can be used - at night - as a refrigerator. Here is how this is done.

The Solar Funnel Cooker is set-up just as you would during sun-light hours, with two exceptions:

1. The funnel is directed at the dark night sky. It should not "see" any buildings or even trees. (The thermal radiation from walls, trees, or even clouds will diminish the cooling effect.).

2. It helps to place 2 (two) bags around the jar instead of just one, with air spaces between the bags and between the inner bag and the jar. HDPE and ordinary polyethylene bags work well, since polyethylene is nearly transparent to infrared radiation, allowing it to escape into the "heat sink" of the dark sky.

During the day, the sun's rays are reflected onto the cooking vessel which becomes hot quickly. At night, heat from the vessel is radiated outward, towards empty space, which is very cold indeed (a "heat sink").

As a result, the cooking vessel now becomes a small refrigerator. We routinely achieve cooling of about 20º F (10º C) below ambient air temperature using this remarkably simple scheme.

In September 1999, we placed two funnels out in the evening, with double-bagged jars inside. One jar was on a block of wood and the other was suspended in the funnel using fishing line. The temperature that evening (in Provo, Utah) was 78º F. Using a Radio Shack indoor/outdoor thermometer, a BYU student (Colter Paulson) measured the temperature inside the funnel and outside in the open air. He found that the temperature of the air inside the funnel dropped quickly by about 15 degrees, as its heat was radiated upwards in the clear sky. That night, the minimum outdoor air temperature measured was 47.5 degrees - but the water in both jars had ICE. I invite others to try this, and please let me know if you get ice at 55 or even 60 degrees outside air temperature (minimum at night). A black PVC container may work even better than a black-painted jar, since PVC is a good infrared radiator - these matters are still being studied.

I would like to see the "Funnel Refrigerator" tried in desert climates, especially where freezing temperatures are rarely reached. It should be possible in this way to cheaply make ice for Hutus in Rwanda and for aborigines in Australia, without using any electricity or other modern "tricks." We are in effect bringing some of the cold of space to a little corner on earth. Please let me know how this works for you.

[eppur_se_muova]

25. Egyptians have been making ice on their rooftops at night for centuries.

"An Egyptian fresco from 2500 B.C. shows slaves fanning water jars, an early record of human efforts at cooling. The people of ancient Egyptand India knew how to make ice by exposing jars of water to the clear night air. While both societies credited supernatural forces for this phenomenon, it was a combination of evaporative cooling through the porous jars and radiational cooling into the night sky that chilled the water and froze its surface."



However, I had been wondering about the use of a solar reflector for this purpose. Thanks for satisfying my curiosity.

[1monster]

18. Cool! I just printed this out for my son to use as a possible science project...

and maybe figure out some other projects from it.

(Also, just in case we ever NEED it.)

[Javaman]

26. sigh. she stole the idea from someone else. it's called a Zeer pot and has been around for

at least 13 years.

this "humanitarian" wants to make money off Mohammed Bah Abba who invented the device in 1995 and whose idea won him the Rolex award for helping poor Africans preserve their foods via the Zeer pot.

here's a link: (I think this woman is despicable)

http://www.scienceinafrica.co.za/2004/september/refrigeration.htm

http://en.wikipedia.org/wiki/Pot-in-pot_refrigerator

http://en.wikipedia.org/wiki/Mohammed_Bah_Abba
Mohammed Bah Abba is a Nigerian teacher, from a family of pot-makers, who became famous after receiving the $75,000 Rolex Award for Enterprise for his pot-in-pot cooling system for refrigeration.

[Nihil]

27. Sigh. The OP was from the Daily Mail (again) ...

... and most of the readership still thinks that the Empire
would be thriving if those brown folks would just stop dying
and get back to work on the plantations ...

(i.e., it is not only an unreliable source of news but is also
about the most right-wing tabloid around.)
:hi:

[Javaman]

28. Ahhh that explains it. thanks. :)

cheers!

[FedUpWithIt All]

29. I was just about to post this.

Inventor of no-electricity refrigerator wins Rolex award
Posted by Mark Frauenfelder, March 22, 2004 9:50 AM | permalink

pot-in-potMohammed Bah Abba of Nigeria won a Rolex award for his "pot-in-pot refrigerator. It consists of a smaller clay pot inside a larger clay pot. The gap is filled with damp sand. As the sand water evaporates, the inner pot cools. Food that used to spoil in a few days now stays fresh for weeks. Second-order effects are already being noticed -- for one thing, girls who had to skip school to sell food at markets can now attend classes. Link (Thanks, juju!)


http://www.boingboing.net/2004/03/22/inventor-of-noelectr.html