so in Catalonia I had this set up
just as a proof of concept I didn't have you load attached, it was
just to see what kind of voltage I was getting what kind of rpms and just that
it would work, basically The turbine is currently
putting out 192 Watts with a 2.5 meter drop and about... I'd still need
to measure the flow rate but it's about 35 litres per second. The sweet spot, like
the top of the power curve, is around 60 something volts at three-point-something
amps. So, 192 / 200 Watts. The cost of this is still about €40.
I call up the 50 dollar water turbine just to be safe, it's actually less than that depending where you get it, but all of these
materials are available pretty much everywhere in the world, it's just standard PVC,
which I've found everywhere that I've ever been, like you know in cities and
towns and that sort of stuff it's a hover board wheel, as an
alternator. That's not going to be so available in developing countries. It's
super easy to get in Western countries you just like, on like secondhand online or
something eBay or local classified site. You can get
like a whole hoverboard for like 20 or 30 bucks, and it's like two wheels,
battery, charge control, all that stuff like they're very good units, and that's,
the alternator is working very well It should be good for 300 to 400 watts total,
and it does really good voltage per rpm And then the impeller is just a computer
power supply 120mm plastic fan And that's it
It's some bits of PVC, it's nuts and bolts, and an alternator and a fan So just a quick walkthrough of how I've
been testing this, it's very basic I've got the three phases from the alternator
coming through a three phase bridge rectifier to convert it to DC, and then
I've got a voltage meter just across the DC output in parallel. I've got an amp
meter in series coming through to the load, and then that goes back to the
other DC channel. In like testing like wind turbines and other things I need to
test I'll be basically doing exactly the same setup because it works really well.
The liquid rheostat is just a plastic bottle with a water and washing soda mix
and then two stainless steel cable electrodes, basically, one of which just
stays all the way in the water, and the other one I can pull in and out to set
the load and that's so... and then the one that's static just has tape along it
so that only the very end is in the water. So when this electrode is just
touching the water it's maximum resistance minimal current,
and then when it's like all the way in almost touching here it's minimal
resistance, maximum current. I don't need to know I don't need to get it exactly
the right ohmage, I just need to be able to set it to varying points and I read
the current going through it and the voltage going through it directly with
the meters. And then that lets me calculate the power, basically. So all of this is not part of the turbine, this is just the test rig.
So obviously you wouldn't use this with like a container in a window that you
have to pump full, this is meant to go in a river, it's just that there's no drop
in Berlin, it's all completely flat So here the CADUS workshop they're letting me use it's been the perfect situation, just because I can have like
all of this right next to the window next to the river and do it on a really
super controlled scientific kind of like way, like changing one thing, testing it..
I never have this kind of luxury like usually I'm like knee-deep in like a river
somewhere with everything exploding Just trying to hold it together
let alone getting you know good data, so this has been really good.
So the good thing about hydro turbines is that they produce power, as long there's
like a water supply, 24/7 so this doing 200 watts means it's doing 200 watts
constantly, which is about five kilowatt hours per day. Which is enough to power
about a third of a Western suburban home like entirely, so three of these will
power your house. That can be like in parallel, if you've got enough volume, or
in series if you've got enough flow enough drop. In a global south / developing
country kind of situation this will power a lot more houses than that Maybe, you know, ten, or something,
depending on the power needs So what's happening here is I've got a
submersible pump in the water, which is filling this bucket, which I'll describe
in a second, and then use that to fill the tank, and then use this to fill the turbine
to this tap here And when this all fills up, as it
has now, turn off the pump Close off this 'valve' here, just some tape,
and then the purpose of this bucket which I've had to reinforce because I
imploded like five of these things like the amount of pressure was
a lot more than I thought it was That's now, as this water drains
back out of the system into the river because there's another valve on the
pump, that sucks this air, the last bit of air that was here, out of the system,
close the tap... You can see like the pressure this is under, like it's doing a
surprisingly a good job, and that's what all these like reinforcements are for,
otherwise it *Squish* As happened five times So this is full, this is ready to go,
this lever here, these strings go down to just like a flat gate I've got at the bottom, just like a plastic funnel as a sort of like shape to
keep the water in, basically. So I crank this back tight, that blocks off the bottom,
when I pump the water in here it fills up from the bottom, fills the system, and
then now this is ready to start the siphon Like I say, in the field, how this
will actually be used by people like what I had in the last video in
Catalonia, and here, with this whole up-over-and-down style like full siphon,
that was because in Catalonia I was going over the wall, out of a mill run
that was being fed by a river here I'm coming out of an IBC... I think
I'm losing a lot of power to that full siphon system, and in the like actual use
case it's probably going to be more like just like a straight pipe with a little bit
of a bend at the end which basically plugs into like a bit of a river, like
the drop in a river, which means that all of this will be unnecessary. All you're
gonna have is going to have like the turbine assembly with the fan and the
alternator and then like some feed pipes in and out and that's it. So it's going to
be simpler than this, it's not going to have any of this testing stuff, you just
plug it into a river fill it up, let it go, and it'll do more
power than this is doing The next phase when I'm back in Scotland
will be plugging it into like an actual river using it like in the field, find out how
it does over time. People have sort of like raised concern the
plastic fan might not be strong enough and they might be right. So far it's holding
up really well, haven't had any problems with it at all, but it's not been going
for months and months. If it does break under actual 24 hour use then I've got
options to reinforce that and I'll see if those are necessary, see how they
work, but this is not the field test this is the power test Show you the inside of this turbine Screws are just so it doesn't fall apart
when it's under weight So, that's her, basically So essentially there's only one moving
part of this, you've got your turbine directly on a shaft through the back to
the alternator, just driving that direct drive So this is a 120mm standard computer cooling fan Just plastic, but so far is dealing okay,
haven't had any breakages with it at all we'll see how it goes over time. Just loosen this off here So the assembly method here is quite simple and works quite well So that's the shaft.
So this is coming out of just like a little connector nut, here.
In here is a bush bearing which keeps it centered at the front, this is basically
just a circle of plastic chopping board so nylon or PTFE or whatever it, whatever
kind of plastic they use So just like, cut a circle, cut a circle out of that Just bolts through, just to lock it into the center That's strong, it's good and strong you want to recess your bolt heads here
so for that pipe can we come over that the one that connects to it.
And then here you just got just a stack of washers around the shaft, around
the thread, and so that sits inside that bush So there's like, there's slip between
the shaft and the washers, and between the washers and the housing.
So it's really low friction, nice and centered it doesn't rattle around too much, super easy to make, costs basically nothing and won't corrode. So using like a bearing or
something in there you'd have to use like a ceramic bearing or something, which, I mean, blech. So the method for attaching the fan onto the shaft here I've just got like a circle of plastic, drilled
an 8mm hole through both of these I'll be doing a full build tutorial on all of this So all the step-by-step how to make it and everything So the method here is I've got a circle plastic, two nuts-and-bolts...
those are just so that those heads come into contact with the wings of this wingnut.
So the wingnut is locked tight, as tight as I can get it to this lock nut here so that it basically can't slip,
and then... that just hits on there so that as that turns it drives the whole shaft that sits in the housing,
and the whole thing turns nicely So the other end here has just got
a couple of wraps of insulation tape and that just goes through there There's a gasket here
which I'll show you in a second so that just comes out, you have a washer
underneath there That goes into there, and then that just
winds in, basically So I've taken the front plate off the alternator,
and I've drilled a hole in the center of the face and put
like a countersunk bolt facing outwards Onto that I've locked tight a wingnut,
and a lock nut, and then a connector nut And then if you can see I've drilled two
holes into the face here to take the wings of the wingnut, so that as this
turns it turns the whole assembly The main reason for that is that;
this can wobble a bit, so this gets pulled out and tight by the weight of
the water on the fan, but See none of this is like precision-engineered,
so I don't want to have to align everything perfectly. So this being a
little bit wobbly and with a little bit of give means that it basically makes it
into a universal joint, so if there's any misalignment between this front bearing
and like the the alternator then it's accommodated for in the the
slight give of of that connection there But it's also super strong and can't
slip against the alternator and you can make the whole thing with nuts and bolts,
super easy, for basically no money So under here I've got like the gasket to stop air getting into that system I've got an 8mm shaft going through a 10mm hole that's so the shaft, again, doesn't have
to be perfectly aligned with that hole, there's some give in that and then just to center the shaft in the hole;
here at the back I've just got this connected super simple, just on to the shaft of the
alternator, the hoverboard wheel with just two bits of steel on these two
threads. I can set this by winding these nuts on and off, and I can set the Y
axis by releasing one side and then just like forcing this over like a couple of
millimeters by squishing these two together winding them together, and then locking it off again.
So I've got basically like XY positioning on the alternator assembly
just with, again, just some nuts and bolts I'll show you the gasket.
I had to try a couple of different options for getting this to work nicely and now it's
super low friction, super low air intake In future versions I will glue this down
rather than using tape, but it's a test So basically under here there's the hole,
coming out of here this is an old hole that I was using as an
air intake, ignore that So the shaft comes out, comes through
the washer, and then there's an O-ring that goes on to there. That sits on
the tape that's on there, and it's sort of like it's eaten into the tape a little bit,
but that's a good thing, because it just forms like a nice sort of like housing
for the O-ring on the shaft Otherwise the thread would let air
slip in through the O-ring And then I've just got a square of closed cell, has to be closed cell, if it's open cell it will just suck air through itself, square of just like foam rubber type stuff which sits over that, and that just sort
of like seals on to the O-ring on the top and just stops air from being able
to get around it or under it or something The gate is fairly simple but works really well This is just a plastic funnel
with the nose cut off which happens to be exactly the right size
to fit up inside here where you've got this the gasket which is built into the the
pipe assembly which grabs onto it and then these strings just pull that tight
and that locks in and then takes the weight pretty well. You just got a cloth hinge
on the back so that it doesn't fall off and so that the in-and-out of this can like
vary like a little bit This lever system works quite well just
for giving this like a good amount of tension I can get this nice and tight, but it
locks in so that it can't be pushed out by the weight There's about 60kg of water, on that gate, so it needs to be properly tight so one of the main kind of improvements
that I made on this; so imagine this is like vertical pointing down to the water,
was to move the assembly from at the back where I had it in the last video in
Catalonia, directly over the drop This seems to help. I increased the down
pipe from 125 to 160mm. This was to have more water go through the system,
but it didn't really increase that by so much because the 125 sort of
throttles it down. It's kind of like a lowest common denominator kind of thing,
it kind of goes as fast as the thinnest amount of diameter of
pipe will allow it but it did increase the flow a little bit.
The main reason for increasing that is that I was getting quite a lot of
cavitation coming off the back of the fan so of I've played around with like
nose cones and tail cones Off here this is the cap of the bottle of spray-on antiperspirant which goes on to the front there.
That doesn't seem to make too much difference I've tried it with and without and doesn't
really seem to help so much It did cut down on the cavitation, but it
didn't really increase the overall power so much The purpose of this sort of
increase of diameter here was that when the water passes the fan and enters this
large diameter section of pipe it slows down So the liters per second stays the
same but the meters per second is reduced so the faster the the water is moving
the more it like tears off surfaces and that's where the cavitation comes from. So as
soon as it leaves this fan, it slows and that stops it from separating out from
the fan, separating out on the wall and then it's got like a straight drop
to the water. Another improvement that I made was dropping the pipe into the
water, because as soon as I increased the diameter of the pipe, basically if I
put it under any load, air would get in up inside the pipe and climb to the top
and then break the siphon, and the whole thing would stop very quickly. So having...
so I increased the length to about 2.5 meters which gave me some more power, just
because of that, but also that meant I could have the pipe under the surface of
the water so there was no way for air to get in So I experimented with a few attempted
improvements on this One was to put like
a stator turbine in front of the impeller to kind of like direct the water
onto the blades Tried a few things, none of them were
pretty, this being an example of how ugly these things came out. So taking
this out actually increased the power so this is either not a good idea, or just
needs to be done a lot better than this horror show, we've got here The nose and tail cones, as I say, probably
help a little but I don't know that it's enough to
make it worth doing, although it's just a bit of plastic so it's easy.
Also in here I had some polystyrene just cut to shape to kind of like block up
this sort of back section just so the water would come through
smoothly and cleanly I haven't had a chance to directly compare
with and without that to see how much help it makes,
but on the next build I will And those are most of the improvements
that I sort of tried The ones that helped and the ones that didn't. As it is now I can probably squeeze like a little
bit more efficiency out of it but I'd say it's pretty much good to go.
So this is, I'm happy to broadcast this design now, I'm happy to to start working
on the tutorial on the full step-by-step, which will be on
the website: opensourcelowtech.org And I will put one of these in the field and
have it running for months and see how that goes, but this is ready to make it's doing the power that I wanted it to do,
it's costing what I wanted it to cost So with this compared to like say a
hundred watt solar panel is that this does twice as
much power also a solar panel will produce power
for maybe five or six hours a day so if you've got a hundred Watts coming
out of it, which means it's running, you know pretty optimally, you might get five
hundred watt hours per a day. This will do 200 Watts 24 hours a day.
So about five kilowatt hours per day So 10 times the amount of power per a day
as opposed to a solar panel A solar panel in a lot of places will cost you
60 to €80, this will cost 40 to €50 so it's half the price and will do 10 times the power
Do you know of a DIY wind turbine?