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Making Ice Without Electricity
j-beda writes "Time Magazine is running an article telling us how Dave Williams is trying to make ice for third-world applications using the Hilsch-Ranque vortex-tube effect (first developed in 1930 by G.J. Ranque), where swirling air is split into hot and cold components." The method is horribly inefficient but Williams is hoping it could yield helpful results in areas where electricity is really not an option.
In Winnipeg we just leave water outside for a few minutes.
Trolling is a art,
How about we try and ensure we give them clean water first. The only use for this is in refrigerators and keeping food fresh.
Ooo man the floppy drive is broken. No wait. The computer is just upside down.
I think that we all know that it's already been tried, and baaaad things happened as a result:
http://www.imdb.com/title/tt0091557/
I don't respond to AC's.
The water leaves YOU outside for a few minutes.
How can you rotate anything without moving parts?
The gas moves into the chamber under pressure. The chamber is shaped to send the gas into a whirling vortex. Then the hot molecules go one way and the cold ones go the other. But I think it takes very high pressures to produce the required speeds.
... Time really needs to get its story straight with regards to scientific reporting. This method is a) not innovative b) not practical and c) REQUIRES SIGNIFICANT ENERGY INPUT. Vortex tubes have been around forever, and they are not some form of perpetual motion. It is a well-understood effect, and one which does not violate any of thermodynamics. You put in a lot of energy via compressed air, and get output in the form of a thermal differential. The key point is that you need a lot of high pressure input...where is this going to come from? Electricity. Unless you use a combustion engine to turn the crank on a compressor, in which case that's your energy source. What are villagers in rural india going to do? Blow really hard through the tube?
If you can spin something at 1,000,000 RPM why not spin a copper coil inside a magnetic field and make electricity instead? Quite useful stuff I've heard.
According to the article this method doesn't require electricity. Then where does the energy to generate the required volume of compressed air come from? Hand pumps?
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Why try to develop something entirely new, with the resulting time and money requirements? A few solar cells + Peltier coolers + some insulation and an ice tray. Yes, Peltiers are inefficient... but they're solid-state, at least, which I think ought to do for remote areas as far as durability. I would think you could assemble a decent mini-freezer out of things portable enough to carry anywhere:
1) Flexible solar panels (less efficient but more portable than glass)
2) A handful of Peltiers... they're pretty small
3) A couple of cans of "Great Stuff" spray-in insulation, or cans of A-B component expanding insulation
One of my friends went to Peru to assemble a non-electric solar water purifier, and anything they couldn't carry on their backs on 30-mile-a-day hikes for a week didn't go. Now that's a design constraint!
Couldn't read the full article as it is now "premium content" but if you can make compressed air you can make electricity, and use that electricity for more than refrigeration. The comments about the vortex tubes' inefficiency are correct, so even if you figure the inefficiencies of (solar/labor/water power) to electric then operation of either a freon or Peltier cooler, you are better off.
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If someone wants to do something really interesting for the third world, make an adsorbtion freezer using solar concentrators for the heat source. This article discusses some issues: http://me.sjtu.edu.cn/english/scientific_research
The Romans used to make ice in the deserts of Palestine and North Africa. It seems to me they were around before electricity and Frigidaire.
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http://www.madsci.org/posts/archives/nov99/941723
Of course, the large temperature difference between the day and night in the desert it what drives it. That method probably won't work in tropical climates.
-Charles
Learning HOW to think is more important than learning WHAT to think.
The President leaves you in the water outside for a few days.
For those who didn't read TFA, and haven't ever read about the operation of these devices, Tim Cockerill wrote his thesis about them. He provides an excellent reference for the thermodynamic operation of these devices. You can put down your tinfoil hats, as they do obey classical thermodynamics perfectly well.
here is a picture of one. it makes it easier to see how it works.
HERE
Create a 10 mile high structure. Send water to top. Bring ice back down.
My mothers house has 2 ammonia Air Conditioning units built in the mid to late 40's they were "Overage" for a bank and made their way into my grandfathers new home, since it is a hot water heated house its great, let me tell you these things will even chill the upstairs of the house , at 2000 ish square feet to push cold up is not a bad trick, the volume they output is the key.
:) Designed well, and built like German tanks...
The funny part ? They still work flawlessly, and have not been serviced since at least 1977 ( In know this for a fact as thats when my grandad passed away)
Their electric consumption is actually minimal, running both all month equates to about a 60$ electricity increase. Unreal if you ask me, I kept thinking we were on an electric budget the first summer I fired em up in 20 years as it was way to hot for my grandma without air so I told her I would cover the bill. it never went up....
The beauty is these units will spill the ammonia outsie through the exhaust should the coils ever rupture (I doubt it since they are about 1/8 in thick copper
Back when I lived in an African village, 1989-92, we had a kerosene refrigerator. All I had to do was trim the wick occasionally and keep feeding it fossil fuel and it kept things cold/frozen for me. A co-worker of mine in another location converted his to burn butane by putting a bunsen burner in place of the kerosene wick.
Although we certainly used our fridge for food and ice, it was also very important to refrigerate meds for the clinic in our village.
Making ice without any electricity happens everytime I try to talk to a girl.
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I prefer the elegant simplicity of two grossly different sized gears.