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Coffee House => Coffee House Boards => CH / Science and Technology => Topic started by: blobrana on January 01, 2007, 07:01:19 PM

Title: More Power, Scotty!
Post by: blobrana on January 01, 2007, 07:01:19 PM
"It is a mechanical problem that has troubled scientists since Archimedes and the ancient Greeks, but now a Scottish electrician has come up with the answer - and it could help consumers save thousands of pounds in energy bills.
Ian Gilmartin, 60, has invented a mini water wheel capable of supplying enough electricity to power a house - for free.
The contraption is designed to be used in small rivers or streams - ideal for potentially thousands of homes across Britain.
It is the first off-the-shelf water-wheel system that can generate a good supply of electricity from as little as an eight-inch water fall. "

Read more (http://news.scotsman.com/scotland.cfm?id=5492007)

A portable, water powered computer anyone?
Title: Re: More Power, Scotty!
Post by: Karlos on January 01, 2007, 07:21:48 PM
We get a lot of rainfall in Manchester but there's a lack of streams for the most part ;-)

As for the various canals, they seem pretty sluggish...
Title: Re: More Power, Scotty!
Post by: Vincent on January 01, 2007, 09:18:45 PM
If it can generate enough electricity to powre a house from an 8 inch waterfall, then why not make your own waterfall and use it to power the waterpump of the waterfall itself aswell as the rest of the house?

That'd solve the problem.
Title: Re: More Power, Scotty!
Post by: Karlos on January 01, 2007, 10:09:29 PM
Quote

Vincent wrote:
If it can generate enough electricity to powre a house from an 8 inch waterfall, then why not make your own waterfall and use it to power the waterpump of the waterfall itself aswell as the rest of the house?

That'd solve the problem.


That would essentially be perpetual motion, which contravenes the basic laws of thermodynamics. In other words, it wouldn't work ;-)
Title: Re: More Power, Scotty!
Post by: Cymric on January 01, 2007, 10:20:29 PM
Don't get your hopes up. I calculated that to obtain a power output of 2 kW at the specified efficiency of 0.7 and a hydrodynamic head of 18 inches (= 0.45 m), you need a water flow rate of 0.65 m^3/s. You can make do with less, as the water not only creates downwards inertia by travelling down 0.45 m, but also has a sizable amount of horizontal intertia too. Using a clever design, you can probably tap some of this energy too without immediately creating a reservoir.

Nevertheless, 0.65 m^3/s is a pretty big stream to have in your back yard. I looked up some flow rates of rivers and then discovered that the river Semme which flows alongside the vacation house of my girlfriend in central France has the right débit. Here's a picture of the Semme at a wider point; you should think of the width at the place of the visible kayak:

(http://www.maisonbergere.com/art/kayak.jpg)

Not a big stream, but not exactly small either, and definitely not something we all have in our backyard. The inventor is quite a smart bloke to extract energy from the stream at such a small hydrodynamic head---that is certainly a very clever invention---but it unfortunately won't be a device which will see much use.
Title: Re: More Power, Scotty!
Post by: Vincent on January 01, 2007, 10:25:26 PM
Quote

Karlos wrote:
That would essentially be perpetual motion, which contravenes the basic laws of thermodynamics. In other words, it wouldn't work ;-)

Not if the energy was stored before use :-P
Title: Re: More Power, Scotty!
Post by: Karlos on January 01, 2007, 10:30:27 PM
And when it is depleted?

Basically you are suggesting using a motor to turn a dynamo which in turn powers the motor (substitute motor for water pump).

If the dynamo is 70% efficient, the whole system loses energy regardless of the motor efficiency, and that's before you take mechanical loss (vibration, sound, frictional heating etc)
Title: Re: More Power, Scotty!
Post by: Vincent on January 04, 2007, 02:36:30 AM
That'll teach me to try and think whilst being extremely pished :lol:

--edit--
Although, I'm very impressed with the spelling and grammer of my drunk posts :-D

What my brain lacks I must make up for in co-ordinance.
Title: Re: More Power, Scotty!
Post by: InTheSand on January 04, 2007, 03:26:56 AM
Quote
Karlos wrote:
That would essentially be perpetual motion, which contravenes the basic laws of thermodynamics. In other words, it wouldn't work ;-)


Heh! As a kid, I always wondered why someone didn't make a solar-powered light that could just "power itself"!! Would be a nice way to save energy if it was true!

 - Ali
Title: Re: More Power, Scotty!
Post by: motorollin on January 04, 2007, 02:19:06 PM
Quote
InTheSand wrote:
Heh! As a kid, I always wondered why someone didn't make a solar-powered light that could just "power itself"!!

I used to think the same thing when I was a kid :-)

--
moto
Title: Re: More Power, Scotty!
Post by: Karlos on January 04, 2007, 08:44:37 PM
The currents running through superconducting magnets come the closest to perpetual motion as you'll realistically get. Even they need to be "topped up" and you have to expend energy to maintain the conditions required for the superconductivity...
Title: Re: More Power, Scotty!
Post by: X-ray on January 04, 2007, 09:05:40 PM
Ja, there is no such thing as a free MRI scan  :-P
Title: Re: More Power, Scotty!
Post by: X-ray on January 04, 2007, 09:09:45 PM
The solar-powerd light exists:

http://www.solareagle.com/sunmate_flash.html
Title: Re: More Power, Scotty!
Post by: NoFastMem on January 05, 2007, 01:54:49 AM
Quote

X-ray wrote:
The solar-powerd light exists:

http://www.solareagle.com/sunmate_flash.html


I think the "solar-powered light" in question was a hypothetical device which powered itself forever using its own light output.
Title: Re: More Power, Scotty!
Post by: X-ray on January 05, 2007, 03:03:09 AM
Doh!
I misread that one, yessir.
Title: Re: More Power, Scotty!
Post by: metalman on January 05, 2007, 05:40:17 AM
Quote
NoFastMem wrote:

I think the "solar-powered light" in question was a hypothetical device which powered itself forever using its own light output.


That "solar-powered light" is called the "sun" and its on its own timer that can't be changed, however, it turns itself on and off every day, so you don't have to remember.

;-)
Title: Re: More Power, Scotty!
Post by: Agafaster on January 09, 2007, 11:25:34 AM
Quote

Karlos wrote:
We get a lot of rainfall in Manchester but there's a lack of streams for the most part ;-)

As for the various canals, they seem pretty sluggish...


Close, but it should be spelt 'sludgy' :-P
Title: Re: More Power, Scotty!
Post by: Vincent on January 09, 2007, 02:48:22 PM
Quote

Karlos wrote:
As for the various canals, they seem pretty sluggish...

"I once caught a 2lb black ribbed knobbler!"
Title: Re: More Power, Scotty!
Post by: Hyperspeed on February 19, 2007, 01:12:42 AM
I think every home should have it's own flywheel buried under it and solar/wind generators on the roof.

Also, if the water and gas companies are sending us pressurised supplies can small dynamos not be introduced into taps, ovens, garden sprinklers to harness the flow of water/gas?

And it would be good if exercise bikes were fitted with dynamos to offset the carbon footprint of fat people who don't walk anywhere.

There's been talk that energy might one day be generated by solar satellites and beamed down to Earth in the form of microwaves too.
Title: Re: More Power, Scotty!
Post by: mel_zoom on February 19, 2007, 09:48:48 PM
Hyperspeed:

"There's been talk that energy might one day be generated by solar satellites and beamed down to Earth in the form of microwaves too."

Even if that were possible I can imagine it would be an immense disaster waiting to happen :-o
Title: Re: More Power, Scotty!
Post by: Hyperspeed on February 20, 2007, 05:25:43 AM
The US military will test it over Manchester first to avoid killing human beings.

:-D

(http://www.nbma.com/cat/oct98/deathstar.jpg)