Wind Power

[TimberWolf]

Average UK rainfall is about 900mm (but varies regionally from about 550 to 3000mm).

Let's be generous and put you in the rainy West or North West getting 1500mm.

Let's say your roof is 10m x 10m in area = 100m². You'll get 150m³ of water.

Let's say your drainpipes are 10m high, that water will be falling at about 10m/s when it gets to ground level.

1 litre of water weighs 1kg.
1 m³ contains 1000 litres. So 1m³ of water weighs 1000kg. You get 150,000kgs of water per year.

1 newton is the force released from decelerating a mass of 1kg by 1m/s/s.

Decelerating 150,000kgs of water from 10m/s to stationary quickly in a turbine, say 1/10th of a second, might release 150,000 x 10 x 10 newtons = 15Mnewtons. On average over a year (31.5 million seconds) that comes out at about 0.5 Watts. Assuming an efficient generator.

So you could have a 100W lightbulb on for 1 hour in every 200 hours.

##############

Double checking...

Power = Head x Flow x Gravity

Head = 10 metres.
Flow = 150,000 litres per yr = 0.005 litres per second
Gravity = 10m per second (near enough)

Power = 10 x 0.005 x 10 = 0.5 Watts. √

###############

Apparently, water turbines are very efficient compared to wind and work at about 70% efficiency.

Answer = about 0.35 Watts.

Even pico hydro power is FAR more powerful (about 300W)

That seems about right, but an easier calculation would be m.g.h to find the [potential] energy content, and for power divide by time.

[RichardCranium]

Where the hell did you get your Engineering degree from?

The cornflakes box.

Where did you get your personality from?

[RichardCranium]

You are confusing knob head who probably has a tulipe degree in arts with a minestrone BEng(Hons)

Come on then, smarty-pants. What is the answer? And include your workings. I intentionally left them in so that I could be corrected, if wrong, since there were so many assumptions in there. What does your honours degree in engineering tell you?

How much electricity could be generated per annum by rainfall coming down from the average UK rooftop?

[Mich the Tester]

I just had a large plate of chili con carne with a whole tin of kidney beans, so I am expecting to release a considerable amount of wind energy within the next few hours.

[minestrone]

That seems about right, but an easier calculation would be m.g.h to find the [potential] energy content, and for power divide by time.

I would have went with Rankine at the first step.

[minestrone]

Come on then, smarty-pants. What is the answer? And include your workings. I intentionally left them in so that I could be corrected, if wrong, since there were so many assumptions in there. What does your honours degree in engineering tell you?

You are getting bugger all, I was never in dispute of that. Just found it funny you wanted to make yourself out to be our engineering Menelaus there.

(What is your degree in so I can take shots at it?)

[RichardCranium]

You are getting bugger all, I was never in dispute of that. Just found it funny you wanted to make yourself out to be our engineering Menelaus there.

Total fail.

If I could buy a .35 watt device that could life a 150 ton weight over the course of a year then I would cut you in on a slice of the profits.

I was right. You were wrong.

You're a bad loser, Soupie.

[EternalOptimist]

You are getting bugger all, I was never in dispute of that. Just found it funny you wanted to make yourself out to be our engineering Menelaus there.

(What is your degree in so I can take shots at it?)

In the second world war, in the western desert, the allies need x amount of supplies per day per soldier. The Germans need x amount per day per soldier.
The Italians need x + 1kg per day per soldier, 1kg extra water so they could cook their pasta. Drove the krauts barmy that did.

see what this discussion needs is a historian, not youse engineering grease monkey spanner wanking weirdos

[Doggy Styles]

In the second world war, in the western desert, the allies need x amount of supplies per day per soldier. The Germans need x amount per day per soldier.
The Italians need x + 1kg per day per soldier, 1kg extra water so they could cook their pasta. Drove the krauts barmy that did.

Is that why the krauts transferred the Italians to us half-way through the war?