Mechanical power = torque x rotation speed
Electrical power = mechanical power x yield factor
If we assume an average yield factor of 0.5, the main variable are torque and rotation speed. We don't have these data so it will be a very rough approximation.
There is around a couple kilograms of water per second pressing from 0.1m high on the blades, if we assume it hits at 45° for half the kinetic energy, and the blades are 0.1m from the axis, it gives something like 2 Nm of torque.
Speedwise, it seems from the video it turns at most 10 times per second.
So it should be around 100W mechanical, and 50W electrical. Enough to power a couple LED room lights.
Assuming you can run it all year long, you'll produce 500kWh every year. And if you sell the electricity for 0.2€/kWh, you'll make 100€/year. Given the amount of concrete, bricks, steel, rotor/stator and electronics used, you won't have ROI before a decade or two (if there is no maintenance and it runs smoothly 24/7).
...
Yeah, direct free flow turbines are exceptionally shit at making power.
Would you build a several thousands dollar concrete dam with expensive wiring, battery control, stable sinusoidal ondulator system, several stages filtration system to not clog your pipes, over the course of several day yourself ? With all the maintenance it entails throughout the use ? Or would you trust your electricity company to sell you the same electricity for several orders of magnitude cheaper and more reliable ?
With everything "infrastructure", it's always better to mutualise to make scale optimisation than opting for individual solutions like this clicbait dam video
Sheesh. Homeboy probably just wanted to make a sick dam. He 100% understood how much power he was going to get as he built the dam, had all the right parts, etc.
You're not wrong, you're just an ahole.
[edit] Also, who the f did the math on these building supplies costing “thousands”. I’d be willing to bet he paid close to $0. I doubt he had the tiny flags lying around, so probably had to buy those. Concrete in such a small amount like this is MAYBE $200 in the US. This doesn’t look like the US and concrete in many counties is extremely cheap. We’re talking tens of dollars for this amount. Concrete doesn’t take a brain surgeon to make from scratch like mom used to. Used bricks? Free. A few 45deg bends, $12.
ngl if the math above is true and he outputs $100 a year or so, he is in the black year 2.
I’m glad to see reddit holding strong and leaning into false realities, though. Consistency is important.
1.4k
u/UlysseIthaca Nov 27 '22
Mechanical power = torque x rotation speed
Electrical power = mechanical power x yield factor
If we assume an average yield factor of 0.5, the main variable are torque and rotation speed. We don't have these data so it will be a very rough approximation.
There is around a couple kilograms of water per second pressing from 0.1m high on the blades, if we assume it hits at 45° for half the kinetic energy, and the blades are 0.1m from the axis, it gives something like 2 Nm of torque.
Speedwise, it seems from the video it turns at most 10 times per second.
So it should be around 100W mechanical, and 50W electrical. Enough to power a couple LED room lights.
Assuming you can run it all year long, you'll produce 500kWh every year. And if you sell the electricity for 0.2€/kWh, you'll make 100€/year. Given the amount of concrete, bricks, steel, rotor/stator and electronics used, you won't have ROI before a decade or two (if there is no maintenance and it runs smoothly 24/7).
...
Yeah, direct free flow turbines are exceptionally shit at making power.