Siphons are one of those physics phenomena that, like gyroscopes, non-Newtonian fluids, and electricity, seem almost magical. Thanks to atmospheric pressure, simply filling a tube with liquid and placing the end of the tube below the liquid level of a container allows it to flow against gravity, over a barrier, and down into another container without any extra energy inputs once the siphon is started. They’re not just tricks, though; siphons have practical applications as well, such as in siphon-powered hydroelectric turbine.
This is an iteration of [Beyond the Print]’s efforts to draw useful energy from a local dam with an uneconomic amount of water pressure and/or volume for a typical hydroelectric power station. One of his earlier attempts involved a water wheel but this siphon-based device uses a more efficient impeller design instead, and it also keeps the generator dry as well. Using 3″ PVC piping to channel the siphon, as well as a short length of thinner pipe to attach a shop vac for priming the siphon, water is drawn from the reservoir, up the pipe, and then down through the impeller which spins a small DC generator.
This design is generating about 9 V open-circuit, and we’d assume there’s enough power available to charge a phone or power a small microcontroller device. However, there’s a ton of room for improvement here. The major problem [Beyond the Print] is currently experiencing is getting air into the system and having the siphon broken, which he’s solved temporarily by adding a bucket at the outflow. This slows down the water though, so perhaps with any air leaks mitigated the power generation capabilities will be greatly increased.
for maximum throughput he needs that generator and turbine near the exit to the siphon. Let Gravity do the work.
When you’re pumpin’ you gottta work that head 😛😛😛
i am not that sure. Speed is probably constant in the pipe else there would be a vacuum somewhere.
That’s the thing, the length under the pump (head) causes a low pressure area just below the impeller which, when it approaches net positive suction head, will cause cavitation/boiling, which then destroys efficiency. If you put the impeller near the bottom you don’t need to worry about this (the increased pressure above the impeller is instead increasing the boiling point).
Didn’t watch the YT… is this using the same ebike motor from the previous experiment?
I wonder how many years that generator has to run to make up for the electrons he burned(*) in that Tesla getting it there.
(*, yeah I know, but the electrons are 100% recycled. Darned ecofreaks, recycling everything.)
he should put a foot valve at the intake so he can prime it without powered tools.
I would have welded it up out of iron to avoid leaks.
Grabby “I risked my life for this!!!” thumbnail = right-click “do not recommend channel”
Right? I’m all about hacks – being resourceful and creating something instead of buying an off the shelf solution is cool and fun. Creating something just for YouTube views / ad revenue is dumb and annoying.
Sounds like a small solar panel and battery would be better, cheaper, and easier to install.
Exactly this. In my opinion HaD has become far too enthralled with cute but mostly useless projects. I’m waiting for an article on some novel way to take cat pictures.
That tool he used to cut the pipe has a name and it’s not what he called it.
Since he didn’t bother to extract any power, he could have used a transformer (or inverter) to get 240V. Or 1kV. Or 1MV.
That would have been more impressive. Wouldn’t it?
TL;DR another yoootooob vid that isn’t worth spending any time on.
Used to work with a guy who had his own hydro system. There’s a name for these types of turbines, powered by the output suction. He learned a lot, about why you want high voltage (lower IR drop), how to keep leaves and sticks out of the intake (sloped grating) and how to deal with ice and drought. He kept at it, finally relocated, and I don’t think he ever got it running the way he wanted…it sure was a learning experience though. One thing he learned is that 10″ PVC pipe is way more expensive that he thought (and only sold in 10′ lengths)
I’m a bit confused here – what does atmospheric pressure got to do with it? I thought it was gravity “pulling” on the water and when the water column with the opening outside the container is “higher” then the one inside (which only goes to the current water level) and thus weights more -> it “falls down”, pulling more water behind it thanks to negative pressure.
If the tube’s wall/form strength is close to negligible it would just collapse under the negative pressure and it wouldn’t work??
Would a siphon not work in a vacuum?
https://en.wikipedia.org/wiki/Siphon?useskin=vector
^^ looked that up between writing 1. and 2. – seems it’s got nothing to do with atmospheric pressure.
barf-worty HaD commenting system – waht happend to my 1. and 2. at the start of two of those ^^ lines there?
ONE.DOT If the tube’s wall/form strength is close to negligible it would just collapse under the negative pressure and it wouldn’t work??
TWO.DOT Would a siphon not work in a vacuum?
And another thing: isn’t the atmospheric pressure “pressing” on the water level in the upper basin lower than the one pressing on the water level inside the open end of the tube?
I mean it has to be lower by definition and air pressure is higher the lower you get…
There’s no such thing as negitive pressure. There simply ‘less than atmospheric’ pressure.
If you experiment, you’ll find that the max height of a siphon is determined by the height where suction pressure exceeds atmospheric pressure. Above that, you simply create a vacuum at the top of the tube.
Same reason you can’t pull water from a well more than 10 meters deep: Atmospheric pressure must be high enough to push the water, and atmospheric pressure is only sufficient to push water up 10 meters (on earth, near sea level, if you want to be pedantic about it).
The counterargument “But my well is 200 feet deep!” I will leave to the utterer to ponder.
Where exactly do you think the pressure differential that makes a siphon work comes from?
You need a siphon… why? Just a pipe at the bottom would solve all those “problems”