# Why not make use of domestic water pressure?

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#### biomedhed

##### New Member
I'm on a fixed rate for my water charge, so in terms of money it costs me the same to have all the taps running all day as having them closed off - obviously not environmentally friendly...however...

there was nothing stopping me keeping the bath tap powering a small generator (dynamo) and charging a battery.

It then dawned on me; why don't we integerate dynamos into our water pipes. Every time we use the tap, washing machine, flush the bog etc we generate electricity and store it in a battery.

#### Leftyretro

##### New Member
I'm on a fixed rate for my water charge, so in terms of money it costs me the same to have all the taps running all day as having them closed off - obviously not environmentally friendly...however...

there was nothing stopping me keeping the bath tap powering a small generator (dynamo) and charging a battery.

It then dawned on me; why don't we integerate dynamos into our water pipes. Every time we use the tap, washing machine, flush the bog etc we generate electricity and store it in a battery.

Because the resulting pressure drop/loss across the generator would mean you would end up with piss poor water pressure for your other uses. Good luck on getting them to raise the system pressure to help with your brainstorm.

Lefty

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#### biomedhed

##### New Member
Because the resulting pressure drop across the generator would mean you would end up with piss poor water pressure for your other uses. Good luck on getting them to raise the system pressure to help with your brainstorm.

Lefty

mmmm i know what you mean but i have actually got this to work - dynamo takes a minimal amount of pressure to generate albeit a very small amount of electricity but is enough to trickle charge a battery. Every little helps... even if that little bit means powering 1 light bulb for 1 minute after a year of charging

#### Leftyretro

##### New Member
mmmm i know what you mean but i have actually got this to work - dynamo takes a minimal amount of pressure to generate albeit a very small amount of electricity but is enough to trickle charge a battery. Every little helps... even if that little bit means powering 1 light bulb for 1 minute after a year of charging
Sure it works in principle but the economics sucks, wastes energy, wastes water resource, etc. Maybe not to you on a flat fee but to your community as a whole. This is like a parasite taking from the host without returning any benefit to the host. Get a solar cell if you just want a little battery charging station going

Lefty

#### biomedhed

##### New Member
Sure it works in principle but the economics sucks, wastes energy, wastes water resource, etc. Maybe not to you on a flat fee but to your community as a whole. This is like a parasite taking from the host without returning any benefit to the host. Get a solar cell if you just want a little battery charging station going

Lefty
Agreed. Was just making the point that we do have an energy source that is literally being pissed down the drain constantly and could be possibly tapped into. Pardon the punn. Obviously it would never be a realistic energy alternative.

Nuclear all the way if you ask me.

#### Leftyretro

##### New Member
"Nuclear all the way if you ask me. "

We are in agreement there

Lefty

#### dknguyen

##### Well-Known Member
Aren't you just stealing the energy the water company is using to pressurize the water in the first place? I mean, they have to pressurize it somehow. How do they pressurize it?

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#### biomedhed

##### New Member
Aren't you just stealing the energy the water company is using to pressurize the water in the first place? I mean, they have to pressurize it somehow. How do they pressurize it?
I wouldn't say steal; more like making more use of it. Most of the energy I guess they use to pressurise it is just lost down the sink.

#### 3v0

##### Coop Build Coordinator
Forum Supporter
This is wrong in so many ways.

In the end water pressure is created by pumps. Even if the water is stored in a tower a pump is used to get it there. (aways exceptions)

It makes sense to me that if you reduce the pressure the flow rate would be reduced.

if eveyone left taps open the pressure in the system would drop and everybody would be angry.

#### tcmtech

##### Banned
The city water mains need that pressure in order to get water to every point on the system. Many of your daily uses dont need that pressure such as filing tubs, sinks, wash machines, toilets and what not.
Capturing that energy as a feasible source of power is possible then and no water is actually wasted.

a general rule you can calculate your theoretical energy from is the rule of 1500. (old school reality based math)
That is 1500 gallons per minute at 1 PSI is one horsepower. 1 gallon a minute at 1500 PSI is one horsepower.

Change your volume, pressure and unit of energy measurements for your application.

to get 1 kw of mechanical power you would need around 50 GPM at 40 PSI. Or 40 GPM at 50 PSI.

So in theory your garden hose running at 10 GPM at 40 PSI can produce about 200 watts approximately.

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#### 3v0

##### Coop Build Coordinator
Forum Supporter
So in theory your garden hose running at 10 GPM at 40 PSI can produce about 200 watts approximately.
But you will need to carry the water to the lawn in buckets.

#### smanches

##### New Member
I dont' think the point is to leave you faucets running, but to use the extra pressure as you're letting it out to begin with. Or, if you were to put it at the feed to your house, reduce excess pressure you might have.

I've though of this a lot. Every other day I water my garden. All that pressure is just going to waste. Wouldn't it be great if you could get something out of it.

I also have very high water pressure here, much more than I need for most things. It would be cool if there was a built in dynamo that would take some of that pressure off me. I never have the shower full open anyway.

It's not about running the water just to make the energy, but to use that pressure just before you let it all go to zero.

#### gabeNC

##### Member
You could put the dynamo at the exit line... well... i guess until that large solid turd clogged it.... nevermind... bad idea.

#### smanches

##### New Member
You could put the dynamo at the exit line... well... i guess until that large solid turd clogged it.... nevermind... bad idea.
LOL, it's not wastewater, it's tap water.

#### 3v0

##### Coop Build Coordinator
Forum Supporter
Where I used to live there was a lot of water pressure in the city water mains. We had pressure regulators that dropped pressure to what was required/safe in the home. One could build a regulator that included a turbine.

I wonder how long it would take to break even.

#### tcmtech

##### Banned
I use about 150 gallons a day minimum myself. about 20 of it needs pressure the rest is just filling something.
So lets say I have 130 gallons per day with a 40 PSI drop. That would give me about 13 minutes with the garden hose concept. So 13 minutes at 200 watts would be about 43 watt hours or .043 KWh per day. In one year I would produce around 15.82 KWh's of electricity or about $1.90 worth of power. Those who water their lawns with city water and have kids and a wife would see maybe ten times that in a year maybe. So say realistically$10 - \$25 a year depending on the person and power cost.

Just a guess.

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#### Alex_rcpilot

##### Member
The real waste in the engery flow is the drain. Wherever the water is pumped to, it returns to the sewer with excessive kinetic energy, especially when it rains down the drain from a 50-story building. But given the fact that it's incredibly gross and there's risk of blocking the pipes, I wouldn't suggest installing a generator inside it at the bottom floor.

#### smanches

##### New Member
It's an unethical idea and it's been bantered around before.
How is it unethical?

#### gabeNC

##### Member
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