Gadzooks! I've had an idea.

[GeeMac]

I'm throwing this into the group for discussion or maybe someone will give it a try.

Most homes have water under pressure delivered right to the tap. Somewhere down the pipe other pipes are met and at some point there is a constant flow of water, so why not use the pressurized water flow to turn a generator before the water is delivered to it's destination? Even small generators that only run when a tap is on might be useful for battery charging. That's it.

Never stop having fun.

[DamonHD]

Because it would be stealing energy from the water supplier put into pumping the water to the house.  Which means energy lost over all, not gained.

Rgds

Damon

[richhagen]

Well, the water supplier in your area had to put energy into the system in order to get that pressure and move that water to your house.  If you add a turbine to capture energy from the water movement in the supply system, then your water supplier will have to put in even more energy than you get from that turbine in order to maintain the pressure in the system.  There is no free lunch there.  I suspect that turning excess pressure at the tap electrical energy is not worth the effort also because of the tiny amount of energy if you look at the overall average flow rate of water into just one home.  I don't know what typical usage is, but if you used a hundred gallons in a day, that would only be .07 gallons per minute on average and that would be spread over a number of taps.  Rich

[joe4324]

Keep the ideas coming!   Once I actually built a tiny LED night lite that I ran off the landline phone service.  It didn't give much useful power but enough for a small lite.  I thought this was a good idea until I realized that while it seemed like i was getting a free source of energy it really wasn't good in the big picture.

Also,  if you un-pressurization your water you have to re-pressurize it again to get back up to pressure,  Due to inefficiency I'm sure this would cost a little more power than you could gain.

[bob g]

there used to be a company that advertised such a unit in popular mechanics or science

about 20 odd years ago, it connect inline with your lawn sprinkler and charged rechargable AA and AAA batteries.

there was a writeup on it and they had a nice photoglossy advertisement for some time

in the magazine.

seemed more of a trinket than something of real value, but who knows.

btw, taking the power of the city water costs the city nothing, they already pay to get the water elevated into water towers, and gravity is what delivers it to you anyway. so if you turn on a tap you are paying for the water used and by extension your share per gallon what it took to get it elevated into that tower.

the turbine generator presents no more load to their system than does the fawcet if you turn it down a bit to slow the flow to the sprinkler.

bob g

[Opera House]

This idea comes up every couple of months.  I's not improving any with age.  

[thirteen]

if someone could improve on an inline generator then it might be able to be used in an gravity flow system. Yes it is an old idea but what is used on an ondemand water heater for spark to light it. The cost would out wieght the gain but it might give you enough the light an indicator bulb to tell you you have water flowing. Just an idea to ponder.  

[Norm]

   By some standards we use a lot of water....

about 200 gallons a day but even at that I figure

the payback would be about 100 years if I

used the hydra system.

  I pedal a generator and charge up 16 AA

batteries in 15 minutes and it was far easier

and cheaper than buying a positive displacement

gear pump and hooking it up to a very special

little stepper motor.

  The pedal generator had already paid for itself

health wise in a month.

[Stonebrain]

I think it might be a good I dea if you FIRST yield the energie from the tap AND THEN use that energie to put it under pression again.Becaust taps in generally leak somewhat,there is LESS WATER to put under pressure and so you have an overall gain in energie.

Thight might be very little but if you repeat the process enough times it might be worth it.

[gagnerargent]

Ok, but is this ethical?

[m8e]

Yes, you don't steal any energy. You are losing water pressure/flow on your own "side".

It's just as ethical as breaking the flow with a valve.

[sbotsford]

Yes, you could extract energy, but then your water in the house would have little umph to it.  It also only produces energy when you are using water.

Energy has units of Force x distance.

Pressure is force/distance squared.

Pressure times volume = F/D^2 x D^3 = F x D

60 psi = 400,000 newtons/meter^2

So a cubic meter of water has the potential energy of 400,000 joules.

A kwhr = 3,600,000 joules.  So 1/9 of a kilowatt hour.

A cubic meter is 1000 liters.  

1000 liters per hour = 4.4 gallons per minute.

So by running at tap full out, you could generate enough power to keep a 100 watt bulb burning -- ignoring losses.

What does your city charge for water and sewer?

[domwild]

In Germany and about 50 years ago I saw a washing machine operating off the tap and using the water pressure. A piston in a cylinder was moving the cross in the washer one way, then a valve switched the water the other way and the piston and crank system turned the cross the other way.

Simple! Water cost very little in those days and no-one thought anything of wasting it.

[electrak]

If you can live with lower water pressure this will work, but it won't make much power unless you use huge amounts of water.  I have seen a water powered LED shower head and a and a water powered shower fan, the fan is a neat idea, just runs when the shower is on.  Will it make money, only if you can get someone else to give you money for it.

[XeonPony]

Well, the water supplier in your area had to put energy into the system in order to get that pressure and move that water to your house.  If you add a turbine to capture energy from the water movement in the supply system, then your water supplier will have to put in even more energy than you get from that turbine in order to maintain the pressure in the system.  There is no free lunch there.  I suspect that turning excess pressure at the tap electrical energy is not worth the effort also because of the tiny amount of energy if you look at the overall average flow rate of water into just one home.  I don't know what typical usage is, but if you used a hundred gallons in a day, that would only be .07 gallons per minute on average and that would be spread over a number of taps.  Rich

Sorry but that is wrong, you are simply going to lose pressure at the tap by converting some of your alloted pressure into power, no more power will be needed to be put in on the utility part.

Inefficient yes, stealing? Nope, stressing the utilities system? Nope.

There is a instent hot water heater that uses a small turbine to power the gas ignition system in it, excellent peice of kit and reliable, for any thing more it is pointless

Keep it real guys.

[joestue]

Well, the water supplier in your area had to put energy into the system in order to get that pressure and move that water to your house.  If you add a turbine to capture energy from the water movement in the supply system, then your water supplier will have to put in even more energy than you get from that turbine in order to maintain the pressure in the system.  There is no free lunch there.  I suspect that turning excess pressure at the tap electrical energy is not worth the effort also because of the tiny amount of energy if you look at the overall average flow rate of water into just one home.  I don't know what typical usage is, but if you used a hundred gallons in a day, that would only be .07 gallons per minute on average and that would be spread over a number of taps.  Rich

Sorry but that is wrong, you are simply going to lose pressure at the tap by converting some of your alloted pressure into power, no more power will be needed to be put in on the utility part.

Inefficient yes, stealing? Nope, stressing the utilities system? Nope.

There is a instent hot water heater that uses a small turbine to power the gas ignition system in it, excellent peice of kit and reliable, for any thing more it is pointless

Keep it real guys.

For what its worth you already lost all that pressure when you turned on the tap, it just went into heating up the water!

Also consider that while opening up the half inch line to fill an aquarium or something bigger in a reasonable time, rarely can you get over 10 psi at the end of the pipe, as its all lost to friction, so in practice, the water pressure is that high because it has to be that high, even for the customer.

[Striider]

Digging up an old thread.  Sorry.  The only way this idea has merit, is if you use stored waste water to create gravity-powered energy for you to "reclaim".  Otherwise, you are robbing Peter to pay Paul.

[thirteen]

My on-demand water heater has a small igniting for the burner to use and it only works when you start water flowing.