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Salt Water Electricity?

 
pioneer
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i saw a show on Netflix (forces of nature- episode2 Elements)last night about how when salt water mixes with fresh water it makes energy. at the end they even do and experiment and shows how to light up a bulb.
I googled and found you can light up a bulb with just salt water.
so my questions are:
1) is anyone using salt water or a mix to make electric for off grid?
2)any ideas on how one could go about doing this?

 
pollinator
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Hmm. My bullshit detector went into the red on this one. Trivially simple to put a battery into the base of these bulbs and either a) wire in a small pressure switch that never gets shown to the camera, or b) edit the video right at the point of dropping the bulb into the "apparatus" when it lights up. Because what they're showing can't work.

These are bulbs designed to screw into a standard household socket and run off mains AC voltage, either 120 or 240 depending on what country you're in. To generate AC power, you either need a coil, a magnet, and movement at a steady frequency, or you need some electronic means of taking a DC power source and manufacturing an alternating current. The simple way to do this is with something that spins, and this is why nearly all power generation is done by turbines of some sort. I don't see anything moving in the plastic cup, nor do I see an inverter, so that means something is fishy.

The second thing I note is that the contacts on the bulb don't get connected to separate conductors...they both get immersed in the salt water. Salt water is a pretty good conductor, so this is about the same as running a single wire to both contacts, which means that there is no potential different between them, hence no circuit and no way for current to pass through the part of the bulb that does the business.

So, in a word: Nope. It's a hoax. They seem to have quite a supply of these videos, all variations on the theme.
 
bernetta putnam
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yes there seems to be a few ways of doing this in the videos even with a speaker ...

anyone actually tried this?
 
bernetta putnam
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looking around some more it seems that there is a battery used. but is the salt water recharging this battery? just like other sources we use do?
here's an article I found, which makes it seem so.

https://www.treehugger.com/clean-technology/salt-water-lamp.html
 
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https://www.redstack.nl/en is a Dutch company developing reverse electrodialysis (RED) technology.
A detailed explanation is at https://www.redstack.nl/en/technology/reverse-electrodialysis-red
 
Phil Stevens
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Osmotic pressure is certainly a gradient that could be exploited, but I wonder about how much water you'd need in order to do this on a scale that would power a modest household.
 
bernetta putnam
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Phil Stevens wrote:Osmotic pressure is certainly a gradient that could be exploited, but I wonder about how much water you'd need in order to do this on a scale that would power a modest household.



exactly I was wondering just how much salt water you would need to charge a car battery or if it would even work...lol
or at least run the lights in a small house.
 
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