PowerSwitch

From animal waste to solar paint, and from hosepipe water turbines to energy generating 'bouncing' dance floors, designers everywhere are generating new and unusual green energy systems in use today.

http://www.power-technology.com/feature ... r-sources/


A good read.

This is going to sound like a really naive question, especially from someone trained in engineering, but I wonder if anyone has considered the idea of a micro-turbine to generate electricity from the water passing through down-pipes from gutters during rain.

Obviously, this is the ultimate in unpredictable, irregular energy sources but, combined with a suitable battery bank and, perhaps, in conjunction with other sources such as wind / solar power, it might make a small contribution.

Every little helps, as they say.

It would be interesting to measure flow-rate during a typical downpour, work out the head and calculate the power-generating potential. Anyone know the calculations?

Sounds like a good way to charge my hearing aid batteries. Occasionally!!

Did anyone see Kevin McCloud producing biodiesel from sewer fat? That has more potential.

Did anyone see Kevin McCloud producing biodiesel from sewer fat? That has more potential.

Hmm.. I think I'd like to explore the potential of the "downpipe hydro" before resorting to sewer scavenging!

Tarrel wrote:This is going to sound like a really naive question, especially from someone trained in engineering, but I wonder if anyone has considered the idea of a micro-turbine to generate electricity from the water passing through down-pipes from gutters during rain.

Bing it, there's lots of discussion.

Quote from this site

For a 5cm dia pipe of 15 metres height flowing full, the power generated will be about 100 to 150 watts. Considering the intermittent production of power even the cheapest system will prove uneconomical.

Given that most houses will have a maximum drop of about 4.5m and you would have to put a single length of smaller pipe in, no joins or seal any joins, to get any head I don't think it would be economical. The power to head is a square relationship so a third of the head is a ninth of the power: 10 to 15W in this illustration.

My rainwater harvesting system collects from about 40sq m of roof and overflows through a 40mm pipe quite happily even in the heaviest of rain so you could be talking about a 25 to 40mm pipe to get full bore running. You would have to have a reservoir above the smaller pipe so that rain didn't collect in the guttering and then run it into the smaller pipe. Rain runs down a 65mm dia rain water pipe as an annular ring around the sides of the pipe, the centre of the pipe is dry air, so that would be unsuitable for generation.

Hope that helps.

Ah well...and there was I thinking I'd come up with the answer to peak oil, climate chaos and everything. Back to the drawing board..

Now then...perpetual motion machines..

There are many "unconventional" ways in which electricity may be produced, but as in the example given above, most do not not produce enough energy to be worth while.

10 or 15 watts for perhaps a dozen hours a year is worth a few pence.
A small PV module would produce more, and at a lower capital cost and with no moving parts to break , freeze, or block up.

It probably depends on the situation. The PV on my van has been a complete waste of money, if looked at purely in financial terms, but it allowed me to stay in one place for longer than I could have done otherwise, and I never ran out of power. So in terms of my comfort, well-being and happiness, it was an extremely good investment. And it powered my internet access, so you were rarely without my words of wisdom while I was travelling .

Maybe a use for rainwater produced power could be for something like a remote shelter that's used in bad weather, where a bit of lighting is useful when keeping out of the rain. PV may be more at risk of theft than a strange box on a downpipe.

kenneal - lagger wrote:Quote from this site

For a 5cm dia pipe of 15 metres height flowing full, the power generated will be about 100 to 150 watts. Considering the intermittent production of power even the cheapest system will prove uneconomical.

Given that most houses will have a maximum drop of about 4.5m and you would have to put a single length of smaller pipe in, no joins or seal any joins, to get any head I don't think it would be economical. The power to head is a square relationship so a third of the head is a ninth of the power: 10 to 15W in this illustration.

My rainwater harvesting system collects from about 40sq m of roof and overflows through a 40mm pipe quite happily even in the heaviest of rain so you could be talking about a 25 to 40mm pipe to get full bore running. You would have to have a reservoir above the smaller pipe so that rain didn't collect in the guttering and then run it into the smaller pipe. Rain runs down a 65mm dia rain water pipe as an annular ring around the sides of the pipe, the centre of the pipe is dry air, so that would be unsuitable for generation.

Hope that helps.

brilliant post