Mini turbine for mains pressure shower

[JCET]

Hi All,

I wish to make a small inline turbine to run an LED light in my shower. The LED light uses about 4.2W and the shower is supplied by mains water at good pressure. (sorry dont know the exact pressure figure).

Im a mechanical engineer so the turbune part for me is easy but would like a bit of help with the electrical side. What would be the best thing to use as a generator?

I should be able to get a high rpm from this so would a small dc motor be the best bet?

Any suggestions/thoughts would be a great help!

Thanks,

Jason.

[Titantornado]

I really can't offer a solution to your request, but I can say that you'll probably be kissing that water saver showerhead goodbye, (if you use one) if you continue forward with this plan.  Remember, wattage equates to a combination of pressure and flow.

I'm pretty conservative with water and energy, and keep my showerhead throttled back pretty tight. (probably around 1~1.5 gallon per minute, but never checked) I doubt there would be a workable solution in my case.

[JCET]

I was hoping that the turbine would also act as a flow reducer. The shower head I have uses a flow reduction valve for home use anyway as it works on low pressure. (its designed for RV's) And so the turbine would replace this and give me some power too??

[Bruce S]

Jason;

  As a fellow ME, I think this would be a good tset of your milling skills :-)

It only took me a few decades to finish mine....

The one item I see a small problem with is the watts you're calling for. 4.2 watts is quite a bit of wattage for LEDs normally the standard LED runs around 3.2Vdc and maxed out at 20ma which should come in ~ .06 watts.

Are you hoping to use a pre-built LED set?

Now to the motor setup. Go find a setpped on kids toys that is AA powered, make sure it is truely broken as in plastics not motor:-) otherwise the wrath will be ooooh:-(

Those little motors when spun by hand make a goodly little of DC and should be a good test point. The best motors would be one that is of the newer ones that have dual axles.

Grab your favorite drill and a handy DC meter, put the axle in the drill and if it's a variable type spin it up after connecting the two wires to the meter. Spin the axle up slowly while either watching or have someone else watching to note the voltages. Once you've gotten to a speed where the voltage does not go any higher make note of that. If you have one that goes above the normal 3.2Vdc then good, as this you can use at a higher speed to light the LEDs by use of resisitors.

You'll then need to design the impellers so that the flow is around both axles, however one should work too. The impeller should be the the same as hyro-"S" type so as to grab as much surfacant as possible , which will also help in slowing the flow.

By memory you'll need to figure an axle tip speed to outer diameter to be on a high order possibly 200:1 or more. I know sounds like a lot , but given the axles are usually measureable in the same as 16 - 14 ga wire this will not be a problem.

Vane propellers might work, but I can see problems with size and fatigue more so that the cup(S) type.

The little wires that will come from the motor will be more than enough to handle the micro-current you'll be pushing.

The Motor should of course be encapsulated by itself and then if possible a venturi effect encloseure for the impellers. This will do two things, venturi will cause enough turblance to slow the flow and enough back pressure to get your impellers moving with a constant output.

I no longer have the milling resources to do this as well, but with some good spare PVC you should be able to build one up with little to no cost (depending on your resourcefullness)

I am on a dial up and pushing this poor 233Mhz laptop to it's max even with a swap file (linux ) of 500 meg, so forgive any speeling misteaks:-)

Cheers

Bruce S

 

[Nando]

WEll daydreams come and go.

You idea as an experiment is good but a "solution" it may not be.

RV shower, if I remember right works with 20 PSI pressure, correct me if wrong.

You will need to produce about 10 watts gross power.

Assuming 10 psi drop by the turbine then the water volume needed will be:

10w/(5*10/1.42) = 0.284 liter/second and the shower may be limited to 2 gallon/min= 2*3.78 liter/minute

Nando

[JCET]

Bruce, Thanks so much for your comments.

The LED cluster is one I actually manufacture and sell through my business. It runs 36 ultra bright 5mm LEDs via an nifty PWM driver and just chose it as we have them... I can reduce the number of LEDs to reduce the power requirement but it would be nice to use all of them as it would light up the whole shower cubicle.

Regarding my machining skills... im lucky enough to have a Roland MDX 20 3d milling machine here (as I do a lot of design and prototype work for companies) which I can just plug into autocad and it'll just about make anything I can draw. So I can design and make a really nice enclosure for this which should help a lot. I was thinking of a simple cross flow turbine which would fit in-line to the feed to the shower and then run the motor from the emerging axle. But I note your points on the different impellors and will give this more thought.

So just really needed to know what the best 'off the shelf' motor would be to use which you have kindly answered for me!

Thanks again for your input.

Jason.

[JCET]

Thanks for your comments also Nando.

The Shower head im using actually uses 1.65GPM compared to 2.5GPM as with most. If anyone is interested this is what im using :

http://www.stormcrystal.com

Regards,

Jason.

[Opera House]

Look at

http://www.ntstainless.co.uk/products.htm

Download the PDF brochure and check out the water powered LED lit taps...

[Bruce S]

Jason;

   I would love to see the 3d modelig of that unit.

How well will the unit work with PVC piping? you may have to build up a clay or wooden model and then build up a multiple piece unit to get the Venturi just right.

What programs are you using to input the needed velocities & back pressures?

Just curious.

Have fun a do send pics of the progress.

btw: PNG files will load up here better size wise if you do load them up.

Bruce S

[RP]

Since you're in the LED lighting business, why consider making a self powered LED showerhead?  If you could fit a turbine in there you'd have something that would make a nifty product!

[RP]

Dang.  I meant "why NOT consider"

[Nando]

This is the classical rain shower, which uses very little pressure, just enough to bring the water to the head and the head ample volume allows "rain" and not pressure shower.

Forget the idea of powering the LED

Nando

[Nando]

This is the classical rain shower, which uses very little pressure, just enough to bring the water to the head and the head ample volume allows "rain" and not pressure shower.

Forget the idea of powering the LED

Nando

[katman]

How about using a magnetic coupled pump in the main water line to charge batteries that can run the LEDs? Change the AC motor to a DC motor to generate the electricity. You might be able to find a 12V DC magnetic coupled pump.

[elvin1949]

RP

 Most of us knew what you ment.

later

elvin

[stop4stuff]

have you considered a Tesla Turbine?

[JCET]

Hi,

Indeed there may be a product in this at the end of the day RussP and this is sort of a development project as well as a solution for my personal use...

There is a couple of self powered shower heads around already :

http://technology.sympatico.msn.ca/MultiColoured+LED+Shower/Wasabi/Articles/Multi-Coloured_LED_Showe
r.htm?isfa=1

http://www.showerstar.net/energy.html

But the first one is more of novelty/ambient light using coloured LEDs and the second just doesnt give as much light as I would like.

I'd like a nice inline turbine that could be be easily fitted with a power feed for my light in the ceiling which would be enough to light the entire cubicle and not just the water stream as in the ones above.

Nando, I take your point about the flow but that is the reason im using this shower head... I'd get rid of the flow reducing valve and the turbine would instead act as this. I'd reduce the bore before the turbine to give me a fast jet of over the turbine thus high mains pressure behind the turbine and low after to feed the shower head. If i was to use a normal shower head that required good pressure it would be no good due to the pressure drop over the turbine.?? As it's this pressure drop thats giving me the power isnt it?

Also, I could control the flow rate via gearing of the output shaft... higher gear = more turbine resistance = more power output = lower flow rate after turbine

I'll look into tesla turbines...

Thanks again for your comments.

P.S. if anyone has any questions about LED's i'll be happy to help.

Regards,

Jason.

[Bruce S]

Jason;

   Interestingly enough I would not have used the "waterwheel" type that the second on your list showed. I would believe that the long term stresses at the tip point would make shorten the life of the wheel. However with due respect to manufacturing, it is the simpler method.

I think going the route of building a unit that fits between the shower head and water mains would be a very good idea, this would make it a retor fit item.

I also noted that while I wrote about the use of a venturi effect, they do call it a flow restricter. Kinda cool.

Their use of opaque plastics is a good idea, though I do like the Wasabi's idea of having a color codes lighting , could even be called child proofing:--) or visual alertness.

There are a few picures of Tesla turbines that are down in the very small scale. By doing a google for Tesla Turbine's there's a webiste for Phenix<-sp? that has tons of data and are very active in design and building.

Unfourtnately, I have been relagated to dialup for now and could not load your companie's website( Linux based laptop as well).

Keep us up on what you come up with:-)

Bruce S

[JCET]

Hi Bruce,

Indeed, will post developments as they happen.

A retro fit item is one im keen to use as obviously it may well have other uses besides a shower light.

I've had a look into tesla turbines and they have got me excited! Im ashamed to say I have never come across them before and is something I might have a play with. Would be very interesting to see how a mini version would work in this situation... and easy to manufacture too! Perfect for my small mill especially if I make it from acrylic which it seems will aid efficiency as the smoother the material the better it seems with these laminar flow turbines as eddys are bad.

Sorry you are having trouble with the site... it is really set up for broadband and flash is also sometimes a problem with Linux. Although adobe have now released Flash 9 for linux but I guess again with dial up downloading that would probably take years!

Im getting an alternative html site developed when I have time to but if you want to e-mail me your address i'll be more than happy to send you some information over.

In fact i'll be happy to offer trade pricing to anyone on this forum for any of our products. The shops force us to raise our retail price as we cant undercut them selling direct from the site and they will insist on there 100%!!

Please e-mail if interested in anything.

Regards,

Jason.

[wreese007]

Try making this small hydro generator at home. It might help you come up with a better idea.

http://www.re-energy.ca/pdf/hydroelectric-generator.pdf