You’re talking about leaving the tap running constantly, aren’t you? I don’t have any suggestions on the technical side, but I think you’ll find that your terms and conditions of supply forbid your plan (at least, if your water supply company is any kind of competent, they will have forbidden it).
Yes, while any power you generate might be “free” for you (at least until you get busted), I don’t think that using purified, mains-supllied tap water to drive a turbine is very sustainable… especially not if everyone has the same idea.
Somebody used free to them water to cool there roof to not run air conditioning in their trailer. That didn’t last long until they were told the water would be cut off if they tried that again. in your case not only do you waste good water, you are causing all that to be treated by the waste water system.
1 Litre of water falling 1 meter generates (to a rough approximation) 10 Joules. Your 4500kW.h per month is 16200 MJ.
So you need 1620 M litres of water. But at the given flow rate of 4.5 seconds per litre, you need to be running the tap for 230 years (at 100% efficiency).
I decided to completely ignore water pressure (because I can’t do that sort of math) and allow a 1 metre fall from the tap to the generator, based on the flow rate given.
I am really just throwing some basic figures about to illustrate the scale of the problem. Increasing the number of taps (until the flow rate decreases), increasing the fall, etc will all reduce the numbers, but there is a very, very long way to go. YMMV.
I work for a public water/sewer utility. DON’T DO THIS! Not only is it ethically wrong, it’s almost certainly illegal. Also, meter or not, the utility will eventually figure out what’s going on.
Anyway, running the numbers, at a typical water pressure, and assuming 100% generator efficiency, you could generate about 150 watts of power with your scheme. At a more realistic 25% generator efficiency, you could generate about 40 watts, about enough for a light bulb.
Running this 24/7 would produce about 28 kW-hr per month, which would save you about $1.75.
And this would cost your water supply utility more than 575,000 liters of water per month.
So in summary, it’s not feasible, it’s a complete waste of water resources, and is generally a stupid idea. :rolleyes:
It’s also worth noting that whatever power you could hope to generate this way is only going to be a fraction of the energy expended by the water utility in pumping it up to the water tower. It would be more energy-friendly just to ask them to write you a cheque for your electricity bill.
