Half a croissant, on a plate, with a sign in front of it saying '50c'
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microhydroelectric turbines

put your domestic downpipe to good use
  (+16, -9)
(+16, -9)
  [vote for,

A tiny turbine, designed to fit inline with domestic rainwater downpipes. You simply cut out a section of pipe and install the microturbine to join the two sections back up. Rain falls down the pipe and drives the turbine generating a small amount of electricity. Fitted to the outside of the pipe is a waterproof battery recharger where NiCad cells can be literally trickle-charged for free.
gravelpit, Aug 14 2001

Kinda like this? http://www.halfbake...a/Urinal_20Turbines
[mrthingy, Aug 14 2001, last modified Oct 17 2004]

Real microhydro power http://www.ghpud.or...lectric_energy.html
[whiprsnapr, Jan 22 2002, last modified Oct 21 2004]

Conversion tables... http://www.engineer...box.com/21_459.html
This site is the closest I've come to what I want... but is it enough? [hankthoreau, Oct 27 2004]

This idea is now fully baked. http://magazine.goo...water-turbine-power
Portland Now Generates Electricity From Turbines Installed In City Water Pipes. [sime0n, Feb 27 2015]


       Sounds like a fun do-it-yourself project. Maybe schoolkids could make some to fit their school's downpipes, and learn a bit about engineering and such. I'll start the voting with a yea.
Dog Ed, Aug 14 2001

       Why stop at down pipes? Engineering prospects for nanomachines should make feasible the attachment of these little gems to interior plumbing. Take a bath, run the TV for a half hour. Do the dishes, listen to a few CDs.   

       Though the idea of harnessing potential energy from falling water is intriguing, the collection of the energy would likely provide an overall inefficient conversion. Look into factors like friction of running water, collection pipe design, rates of rainfall and required revolutions per output of electricity on your turbines.
munkeylunk, Aug 14 2001

       or you could go even smaller and stick a few of these in your arteries, so that each beat of your heart would produce some electricity. you could go for a jog, and power your discman at the same time.
mihali, Aug 14 2001

       [UnaBubba] Different in the following ways:
1.takes its energy from a different source
2.uses private money not public
3.has no "ick" factor that would be a barrier to widespread public acceptance.
gravelpit, Aug 15 2001

       Grumble. Egnor, remind these folks about E = mgh. Small mass, small height = small energy, and the inefficiencies of low-velocity turbines makes the energy gain pretty much negligible. (Unless you have a lake of m or a Niagara h.)
rmutt, Aug 15 2001

       UnaBubba, I thought immediately of HSPG when I read this idea too, but I decided to consider it seperately. And I agree with rmutt that the energy cost to manufacture each mini-hydro generator would probably not be paid back over the life of the device. But I still think it would be a cool educational project.
Dog Ed, Aug 15 2001

       Unless there's so much rain that your downpipe is full, the water will run down the periphery of the pipe, not down the centre. I'm sure this has some relevance.
angel, Aug 16 2001

       I've seen this done on some building on some tv program (sorry to be so vague but it was some time ago), should be links to it elsewhere on the net. It worked ok, generated enough power to run some other part of the building. I like the idea of squeezing the last drop of power from our homes so I'm giving it bread anyway.
darndog, Sep 26 2001

       What [rmutt] said. There's no energy there to speak of. You'd probably waste more energy manufacturing the turbine than you'd ever reclaim.
egnor, Sep 27 2001

       For anyone that is really interested, microhydro already exists in a somewhat different form. The units are commercially available and do break even both from an economic and Enegry Life Cycle Analysis (LCA) perspective. Check out the link.
whiprsnapr, Jan 22 2002

       Hmm this sounds fimiliar didn't somone last week post something about Hydroelectric Sewer Power Generation. Switch it to wind turbines and it could work, Water turbines are only practicle on a big scale, when there is a huge water source.
wood2coal, Jan 22 2002

       Apparently, you can trickle-charge Ni-Cad's, using a crystal radio. Haven't tried it yet. Might figure out way to power PC for free! Cept not. Just a thought.
QuadAlpha, Jan 23 2002

       [wood2coal] Please take the time to read previous annotations. Microhydro DOES exist and does NOT require huge amounts of water to make it practical. Many private individuals in northern Canada have installed small "run-of-river" microhydro generators using the flows from fairly small streams. They generally produce enough energy to power a few homes and any surplus is sold back into the local power grid. Pretty neat huh?
whiprsnapr, Jan 23 2002

       In my experience, trickle charging NiCds is not always dependent on being the most optimally economic solution. Does what it sets out to do +
FloridaManatee, Dec 30 2002

       Unless there was some sort of resevoir, this would be impracticle since rain is fairly intermittent. It also would not collect in sufficient quantities on your average roof to make much electricity, especially with a head of 20 or so feet.
rapid transit, May 10 2003

       I would think that a system such as a resevoir with hydroelectric turbines in downspouts in very doable. Tighten the downspouts to increase speed of water. States such as Oregon, Washington, and even Idaho have enough rainfall and snowfall to make it feasible. The only problem I see is keeping the turbines clean from pollution.
HempFarmer, Aug 04 2003

       Here is my idea. I think it is similar but may add some details.   

       First you gather as much rainwater as possible from the rainspouts on your house into some type of reservoir (preferably in your attic). Attach this resovoir to some piping that has a spigot attached to it with a microgenerator in between the reservoir and the spigot. You can then use/open the spigot whenever you want to water your lawn.   

       The electrical production may be minimal, but it would be something. Attach it to a small battery bank that is used in conjunction with solar or other energy sources. Would it work? Would it be something that physically could be done. I am not looking for something to power my entire house, I am looking for a supplement, for something that will allow me to sqeeze every bit of energy from nature.
Crusty1, Aug 17 2003

       All right... newbie inventor here... but munkeylunk had an idea there that I've been working on for over a year now (not necessarily actively, but mentally) ... a domestic inline plumbing microhydroelectric generator to power small necessities (cordless phones, coffee pots) during power outages, natural disasters (assuming the water lines are 'safe'), romantic evenings, etc. Kind of like a back-up system when sh*t hits the fan.   

       I've done some calculations, and it seems that even at 2.5 gpm with 53% efficency, you could generate .01 kWh, or 10 watts, add a DC/AC converter and, after a short 'pre-charge' period, you could power low wattage lights and some cordless phones... even hot plate in emergencies.   

       I'd love input on this...
hankthoreau, Oct 27 2004

       [hankthoreau] I'll post a link where you can download a spreadsheet and sort of play with the numbers.
Head in feet
nozzle entry arc
flow, if CFS
just about any parameter.

Klaatu, Oct 27 2004

       So, in the system I mentioned, there is NO head... which is defined as drop in elevation, correct? The pipes are laid horizontal, and I think the 'head' number needs to be derived from psi of the incoming water flow... can you derive head flow using conversion of psi, including friction variables, pipe diameter, etc.? I've found a couple of sites that are helpful, but none seem to totally answer the question... am I missing something?
hankthoreau, Oct 27 2004

       Isn't anybody besides myself amused by the use of the word "trickle-charge", or all we all just not noticing how wet it is today?   

       So much rain in San Diego today, I am going to start carrying my freediving gear in the truck in case somebody needs rescuing.
normzone, Oct 27 2004

       Surely even if this isn't viable on a domestic scale, it would work in hotels, tower blocks, office blocks etc.?
wagster, Oct 27 2004

       Over a lifetime, this is certainly a viable idea, and it's definitely an environmental bonus on day one, especially if it becomes a common item.   

       I was thinking of something along these lines, and found this in my search to prove my originality - looks like it backfired.
shapu, Feb 01 2005

       I had the exact same idea myself. Multiply the energy created by all houses in your city and that's a fair amount of electricity every rainstorm.
simonj, Oct 31 2007

       Maybe these turbines could drive a hamster wheel. An actual hamster would be cheaper though.
Texticle, Oct 31 2007

       A hamster wheel the size of London Eye.
simonj, Oct 31 2007

       Does anyone... ever... do.. any.. calculation here? Figure out the energy produced per year, assuming 100% efficiency. Figure out the energy needed to manufacture and install and maintain the device. Divide first number by second number. If answer is >10 start again.
MaxwellBuchanan, Oct 31 2007

       MaxwellBuchanan, I'm happy to go with your numbers, what are they?
simonj, Nov 01 2007

       OK. Average rainfall (UK) about 1m per year. Plan-area of average house, say 200 square metres. Height of average house, say 10 metres. Total mass of roof-rain per year = 200 tonnes (1tonne = 1 cubic metre) = 2 x 10^5kg. Energy available = mass x height x gravity = 2x10^5 x 10 x 10 = 2 x 10^7 joules of energy (20MJ). This is the energy equivalent of 600ml (about a pint) of petrol (gasoline). So, if the device is 100% efficient, it will generate energy equivalent to 6 litres of petrol over its ten-year lifespan.   

       If this is to have any net benefit to the planet, then (a) the device will have to be build entirely out of twigs and recycled string and (b) it will have to be delivered using carrier pidgeons, and installed without the use of power- tools.
MaxwellBuchanan, Nov 01 2007

       These pigeons you speak of still need to be fed.
Texticle, Nov 01 2007

       Yes, but the manufacturing facility can be at the top of a hill. The pidgeons can then glide down. Pidgeon recycling may be an issue.
MaxwellBuchanan, Nov 01 2007

       This may work better in rain-forests
quantum_flux, Nov 03 2007

       There are no pigeons in rain forests.
MaxwellBuchanan, Nov 03 2007

       Okay, based on [simeOn]'s link this is implemented in Portland, Oregon now. It kind of makes sense because the dam for the primary reservoir is about 800' above see level and most of the city is below 400'. But why do they need the turbines inside the pipes like that? It seems like they would do better to just have a conventional turbine at 400' or maybe a little higher, take all the energy out there, then use the remaining height to provide pressure to the city.   

       An implementation like that is nothing new. I'm not sure how common it is, but I just happen to know that in the small town of Metlakatla Alaska, the town water supply as well as their power comes from a building near the ferry dock connected to a pipe running to Chester lake about 800' above sea level. 14 years ago I took a hike up to the lake on a trail following the pipe. You could still see remnants of the decommissioned wooden pipe slowly rotting away, so they have been doing this for quite some time...
scad mientist, Feb 27 2015


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