Half a croissant, on a plate, with a sign in front of it saying '50c'
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Emergency Inline Plumbing Microhydroelectric Generator

Electricity in times of need...
  (+8, -7)
(+8, -7)
  [vote for,

A domestic inline plumbing microhydroelectric generator to power small necessities (cordless phones, home medical equipment, coffee pots) during power outages, natural disasters (assuming the water lines are 'safe'), romantic evenings with dim lights, etc. Kind of like a back-up system when sh*t hits the turbines.

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 a hot plate in emergencies.

hankthoreau, Oct 27 2004

microhydroelectric turbines http://www.halfbake...electric_20turbines
[phoenix, Oct 27 2004]

Figure the numbers for yourself and call me on it... http://www.engineer...box.com/21_459.html
[hankthoreau, Oct 28 2004]

Halfbakery: Bathtub turbine Bathtub_20turbine
Same idea, nastier angle - why wait for an emergency when someone else could be paying for your electricity! [jutta, Apr 10 2006]


       And welcome to the halfbakery.
wagster, Oct 27 2004

       They finally have natural gas generators, which is a huge improvement over having to have gasoline tanks.   

       Great idea+
theircompetitor, Oct 27 2004

       Seems very close to "Bathtub turbine" and "Hydroelectric Sewer Power Generation" above.
FarmerJohn, Oct 27 2004

       [buddha_pest] Very true and agreed... but this system is not necessarily intended to be used 'on demand' per say... more like the energy is stored in batteries during 'pre-charge' and is used when needed for short outages. You can store, with an average battery, about 700kwh... that's a nice buffer of power when you're only powering a few 6W bulbs for necessary light or your life support system for a few hours while you call your doctor (on the phone you're powering because you used all your cell phone minutes arguing with the utility company about your power bill).... kind of like a suspended saftey period. Actually, I think the LSS have back up generators built in... i'll have to check on that, but just to say once again - not for use all at one time in a community, but as an emergency back-up for a shorter duration (say a day or less) during which time you could do some dishes and run a bath with the remaining hot water in the tank, maybe even take a poop (or give a poop, I should say) and add a few more watts during the outage to combine with the 'pre-charged' batteries.   

       Love the input!!! Keep it coming and I'll send you all a cut of the profits...
hankthoreau, Oct 28 2004

       [UnaBubba] You only wish you 'done' this one... read buddha_pest's post, mon petit cheu... low-volume, non-pressurized, contaminated water is hardly equivalent and much less feasible. Think about this one a bit more, and get back to us on it.
hankthoreau, Oct 28 2004

       I take it that the "average battery" isn't a car battery. They store about 0.5kWh (40 amp hours * 12V = 480 watt hours).
david_scothern, Oct 28 2004

       [UnaBubba] Once again... when you run a tub of water for a bath, or water your garden, or run the dishwasher or fill the sink for dishes, it's NOT wasting water... they are tasks that are already occurring daily or several times per week. The idea is NOT to run a bath so you can turn on the lights, or turn the hose on just to charge the battery. The idea is not using current chores which utilize water to provide only ONE outcome, but to provide a source of energy in an emergency in ADDITION to completing your H2O tasks.   

       Is anyone *really* reading or thinking about this seriously? I guess that's a bit much to ask when you're at 'half' bakery... maybe try going 2/3 or even 3/4 baked to comprehend.   

       [david_scothern] You took it right. It would utilize parallel linked 12V deep cycle batteries (or preferably multiple 6V for longer life) as you would find in any RV. Add an inverter and you're ready to go.
hankthoreau, Oct 28 2004

       Wait, so you want to charge this during the normal scheme of things when washing dishes, etc? Forgive me if I'm wrong, but doesn't that just increase the head required to supply your house with water, by an amount equal to the power you're taking out of the system? Your dishwasher needs water under pressure. A turbine needs a pressure difference to generate electricity. If your turbine has taken the pressure out of the water, the dishwasher won't work properly.   

       Increasing the water pressure to cope with this will require the pumps supplying your local water supply to be increased in power.   

       Factor out the turbine completely, and you've got a big battery bank to provide backup power in emergencies.
david_scothern, Oct 28 2004

       Regarding the dishwasher, the water pressure for the machine is supplied by the pump within the dishwasher - it is not a direct inlet. There is a sensor (in most newer machines) letting the pump know when there is enough water to begin spraying. It then engages and continues to fill the washer until the proper amount of water is in the system, then closes the inlet from the faucet. In theory, you could turn the water down to 1gpm and the washer would still perform normally.   

       Agreed, there may be loss of pressure (extremely minimal), but the municipal water supply pressure is relatively consistent considering the minimal pressure loss.   

       Factor back in the turbine, and you have a freely rechargable and renewable supply of emergency power.   

       Now, regarding the 12V battery, I may be incorrect in assuming that these particular batteries would work as a cost effective way to store energy. Will get back to you on that this evening.   


hankthoreau, Oct 28 2004

       how do you power a hotplate with a 10w power supply?
mihali, Oct 29 2004

       The pressure loss wouldn't be "extremely minimal" - it would be exactly equal to the power you were taking from the system.   

       I think that what it comes down to is this: Yes, you could nick power off the water company, but if everyone did it, your utilities provider would have to install bigger water pumps, and the energy cost would get passed on to you.   

       However... I think that my concern still stands. Your water tank isn't in your roof just for fun... it's to provide water pressure. The pressure head needed by a turbine has the same effect as moving your water tank downwards. Your taps will run slowly, the dishwasher will take longer to fill, the shower will need a booster pump and the washing machine will complain.   

       To power a turbine and run your appliances, you need more of a pressure head than just running your appliances. That energy has to come from somewhere. If it's coming from the water main, then more energy has to be put into the water main to maintain service. Eventually it gets back to the water works who have to put energy in with their pumps. Pumps cost money to run. Someone has to pay for it; that someone is the end user so you end up paying just the same. Well, at any rate the cost gets passed to all their customers.   

       I can see the sense in installing backup batteries if you want emergency power during an outage, but I would object on the grounds of their size and maintenance costs. A backup generator would be much more compact and long-lived provided you kept it in good condition and turned it over once in a while.
david_scothern, Oct 29 2004

       [david_scothern] "Your water tank isn't in your roof just for fun"   

       Huh? This is for us city folk who have pressurized water being pumped from a reservoir. There are no storage tanks in the roof.   

       No more energy has to be put into the system, and all the machines that utilize water (i.e. washing machines, dishwasher) may take longer (minutes at max), but the actual performance is not affected.   

       There is no 'nicking' power off the utility company, because there is no excess usage. The inline turbine comes after the fact, and more pressure is not required, just time.   

       Please continue to challenge this. I totally appreciate it, david.   

       [mihali] "how do you power a hotplate with a 10w power supply?"   

       You don't.
hankthoreau, Oct 29 2004

       Genuinely? In the UK, the system works as follows: Water is taken from a reservoir, treated, and pumped up to a storage tank at a high location. This means that there is a store of water with potential head. From there, it flows under gravity to household water tanks in the roof space of houses. Hence, in my house, I also have water with potential head.   

       I guess that, if you have no devices in your home that require water under pressure (a shower being the most obvious example) and you don't mind your taps trickling rather than flowing... then you could take the power out of your water system. It wouldn't work in my house as the shower and washing machine (the only two devices using water) would shut down.
david_scothern, Oct 29 2004

       henry, right in your description you sat that you can power a hotplate from a 10w power supply. a 10w hotplate would be more of a lukewarm plate.   

       anyway, i'm not so sure you understand what mr. scothern is saying. the energy that your system provides must come from somewhere, and in this case, it's the pressure that the city water company provides in your pipes. when you create electricity with your system, the pressure downstream from your turbine will be reduced (because the turbine uses some of that pressure to get itself turning).   

       i think that it would be much more efficient to have a ups system plugged in when you do have power and run off of that when the lights go dark.
mihali, Oct 29 2004

       //I think that what it comes down to is this: Yes, you could nick power off the water company, but if everyone did it, your utilities provider would have to install bigger water pumps, and the energy cost would get passed on to you.//   

       The pressure the water company supplies isn't going to be affected by this device--it is what it is. In most places, this pressure is higher than is necessary (if a third-floor shower is going to get any useful flow of water, the pressure in a basement laundry room will be almost an atmosphere higher). If one were to arrange the plumbing in a building so that water destined for the lower floors went through the turbine while water for higher floors did not, it would be possible to harness some energy "for free", save for the cost of the equipment (which would totally dwarf the value of energy harnessed).
supercat, Oct 29 2004

       This version isn't so bad folks. Remember that older houses have corrosion inside the pipes which increases frictional energy losses & pressure drops. If you have clean pipes, you may harness excess power as needed.
sophocles, Oct 29 2004

       In smaller towns and cities in the US, water is stored in centralized water towers. There is a lot of excess head, many places 75psi or so.   

       Still, the amount of power available in the flow seems so miniscule as to be uneconomical compared with other types of emergency systems.   

       In an emergency, the use of the limited available resources in such an inefficient manner smacks of an attack on the commons. It is similar to a lifeboat where one of the survivors uses the water in the canteen to wash his face.
raytork, Oct 30 2004

       Supercat - fair point regarding the high pressure in the basement, and lower pressure higher up. [UB]'s wastewater version could then be applied to the wastewater from high floors, but not, of course, in the basement.
david_scothern, Oct 30 2004

       [raytork] I think so too. You would be better off attaching your exercise bike to the battery and cycling for half an hour. Wipe away the sweat with a brief apology and sit back down to your romantic dinner. Better yet, ask your date to cycle seeing as you bought the wine.
benfrost, Oct 30 2004

       Oh no we've caught another one. Escape, Henry, while you still can!
RayfordSteele, Oct 30 2004

       Many showers are fitted with regulators to reduce the pressure, and thus save water. If you replaced the regulator with a turbine and generator, you could reduce the pressure and save water, and get some "free" energy on top of it. The problem is that the amount of free energy would be quite small, if you really wanted to use a battery backup and not a generator, you would be better off just charging your bank of batteries (or better yet, a flywheel) off the regular electric service.
JakePatterson, Oct 31 2004

       Are the shower restrictors pressure reducers or water volume reducers?
bristolz, Oct 31 2004


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