Engineers of Oppo, riddle me this:

"Spanfeller is a twat" (theaspiringengineer)
08/06/2018 at 17:32 • Filed to: TAE IS IMPRESSED BY RUDIMENTARY INFRASTRUCTURE PART 2

Why is the electrical station at !!!error: Indecipherable SUB-paragraph formatting!!! 3km downstream from the dam itself? I mean, wouldn’t it be better if the turbine is closest to the dam?

Dam (left) power station (right) estimated path of water (white line)

I mean, according to some environmentalists, the water has to travel five kilometers from the dam to the turbine in this Big Ass (TM) pipe, doesn’t the distance cause friction losses? and in a sense slow down the water causing pressure loss and at the same time slowing the turbine? I don’t know... I haven’t brushed up on thermodynamics yet (oh boy I cannot wait).

The pipe must be 3m in diameter.

According to my research, locals hate this dam, but more than anything, they hate the owners: Union Fenosa. When the dam was built little consideration was put to the environment, so apparently the structure caused the disappearance of some of the species of the Avia river, and it also murders fish because they either get ingested by the turbine, or they die since the water chemistry after the turbine is much worse than before the turbine (Something to do with the pressure and lack of oxygen)

It’s all bad, but at least it supplies energy to the whole area... which was Fenosa’s justification when a group of environmentalists sued for the closure and demolition of the dam. But apparently Fenosa isn’t finished fucking shit up. Apparently when they closed the plant for maintenance water level got so high that local councils had to prep up emergency plans, once it got way too high, they just opened up the flood gates without any consideration and flooded some houses.

Its all very weird, plus, these people fucking love dams. I mean, there’s one like 20km from here, in Castrelo. I will be visiting it.

DISCUSSION (36)

TheTurbochargedSquirrel > Spanfeller is a twat
08/06/2018 at 17:37

PE=M*G*H. The further above you you put the water the more energy you can get out of it. It’s the same reason we had water towers and not underground water tanks.

Spanfeller is a twat > TheTurbochargedSquirrel
08/06/2018 at 17:41

So, the distance from the actual dam doesn’t matter much, as long as they maximize the amount of height it drops when approaching the turbine?

TheTurbochargedSquirrel > Spanfeller is a twat
08/06/2018 at 17:51

Yup. There are some losses with an increased pipe length but they are so small that they aren’t even included in most equations.

Eric @ opposite-lock.com > Spanfeller is a twat
08/06/2018 at 17:54

Why is the electrical station at Albarellos 3km downstream from the dam itself? I mean, wouldn’t it be better if the turbine is closest to the dam?

Because it doesn’t really matter where it is as long as the energy is being transferred. The dams on the Colorado River, for example, don’t do this because they’re exceptionally tall and it would be quite difficult due to the environment.

Their education is highly suspect if they believe this. It ignores numerous laws of physics.

SPAMBot - Horse Doctor > Spanfeller is a twat
08/06/2018 at 17:54

This is kinda my job. In simple terms, the friction loss in the pipe is probably much, much less than the additional head provided from the elevation.

Spanfeller is a twat > TheTurbochargedSquirrel
08/06/2018 at 17:56

Hmm, I should get my dam maths straight.

Spanfeller is a twat > Eric @ opposite-lock.com
08/06/2018 at 17:58

It’s my education which is suspect, They only claimed the pipes were 5km long.

LOREM IPSUM > Spanfeller is a twat
08/06/2018 at 17:59

Would tearing it out and going back to coal or nuclear appease the greenpeacers, I wonder? Maybe they would prefer if they were to ask the trees for permission to blanket the mountain in windmills an d solar panels?

Being a smartass, of course, but even given hydroelectric power, possibly the greenest and most abundantly collectable energy source available to us, people still find cause to cry. If not for the fishies, then for a fern.

Mind you, the folks running it sound like bad actors what with the overflowing and apparent intentional flooding o f homes, but some folks just can’t be pleased no matter what.

LOREM IPSUM > TheTurbochargedSquirrel
08/06/2018 at 18:00

Terminal velocity is terminal velocity, no matter how far you're falling, I'm guessing.

Spanfeller is a twat > SPAMBot - Horse Doctor
08/06/2018 at 18:06

I can’t get a clear reading of the altitude, but from the top of the dam to the bottom its 93m, from the top of the dam to the electrical station it’s 120-140m so it checks out.

RamblinRover Luxury-Yacht > Spanfeller is a twat
08/06/2018 at 18:06

What turbocharged squirrel said. They can make roughly the same power with half the water if it drops twice as far... or even substantially more, because with a lot of head you might have a more efficient turbine, outweighing losses in piping.

Spanfeller is a twat > LOREM IPSUM
08/06/2018 at 18:07

Fenosa is not a good actor.... but the environmentalists are fucking insane if they wanted a forty year old, 93m tall dam dismantled. But again, Fenosa is an asshole, they won’t even build fish ladders.

TheTurbochargedSquirrel > LOREM IPSUM
08/06/2018 at 18:10

Terminal velocity isn’t important in a hydro system because t here’s a metered orifice at the turbine. What’s most important is that putting the hydro station further below the water level increases the total amount of energy you could possibly get from that water.

Spanfeller is a twat > RamblinRover Luxury-Yacht
08/06/2018 at 18:11

I’m afraid of asking (damn, I should really give my physics book a good read) , but, are the pipes usually at the same level as the penstock? or is the pressure of the water used to push the water uphill to then increase the drop near the turbine?

Spanfeller is a twat > TheTurbochargedSquirrel
08/06/2018 at 18:16

I suppose that’s why the penstock is not at the bottom of the dam normally....

LOREM IPSUM > TheTurbochargedSquirrel
08/06/2018 at 18:16

Guessing and engineering. Not the same after all.

Lol, orifice.

For Sweden > Spanfeller is a twat
08/06/2018 at 18:19

Civil Engineering just makes targets for real engineers

Spanfeller is a twat > For Sweden
08/06/2018 at 18:20

Huh?

RamblinRover Luxury-Yacht > Spanfeller is a twat
08/06/2018 at 18:22

It doesn’t really matter if the piping runs up, down, around, however - as long as there’s a continuous body running from below the standing level at the dam to the entry at the turbine. The gauge pressure will be the weight of the water (~82lb per ft^3) times the height, converted to appropriate units of pressure.

There’s no particular advantage to piping in such a way that the pressure goes all the way to max and stays there, or goes up, down, then back up again, other than maybe using weak pipe for part of the run, because the final pressure is all the same.

So, water 300 ft above your point of exit in any piping path, ignoring losses, will be 300 * 82/144 = 170PSI. It’s a reflection of its potential energy - each unit of mass at a certain height has a certain amount of stored energy, and whether that means a small amount of water moving fast or a large amount of water moving slowly, the result is the same.

There are ways to make use of the kinetic energy stored in water to do simple things in wasteful ways, to do conversions (look up hydraulic ram pumps), but turbines are pretty simple in the loose outlines. Mass * speed^2 for a specific turbine, * its efficiency under those conditions = energy. How it gets up to a speed is related to the pressure, pipe size, design attributes of the turbine setup.

LOREM IPSUM > TheTurbochargedSquirrel
08/06/2018 at 18:23

But seriously, is the increased energy potential under those circumstances due to the weight of the water up-pipe, forcing it into the aforementioned orifice harder than it otherwise would were the pipe shorter?

Also, how would that ty pe of setup compare to, say, the Hoover Dam, with the turbines in the dam itself and the lake providing the pressure?

Spanfeller is a twat > RamblinRover Luxury-Yacht
08/06/2018 at 18:25

this is good oppo.

I like cars: Jim Spanfeller is one ugly motherfucker > Spanfeller is a twat
08/06/2018 at 18:27

It’s that joke, Mechanical and Chemical Engineers make weapons, Civil Engineers make targets.

Spanfeller is a twat > I like cars: Jim Spanfeller is one ugly motherfucker
08/06/2018 at 18:29

Well, this dam is not guarded, and the electrical station was also unguarded, all ran remotely. So if any international terrorist wants to fuck up a significant section of Ourense... they could.

TheTurbochargedSquirrel > LOREM IPSUM
08/06/2018 at 18:36

Increased energy due to the increased height over which gravity can work on the water. Basically a higher pile of water exerts more pressure at the bottom.

This setup is just like the Hoover dam in principle. Here the water is above the turbines and flows through pipes downhill to the turbines. At the Hoover dam the pipes are contained within the dam with the turbines located at the bottom of the dam. Dams gain the gravity assist by stopping (or specifically controlling) the flow, which raises the water level. With water the energy contained is dictated by how high the water level is.

TheTurbochargedSquirrel > Spanfeller is a twat
08/06/2018 at 18:37

Exactly.

just-a-scratch > RamblinRover Luxury-Yacht
08/06/2018 at 18:38

[clears throat] didn’t you mean 62.4 lbm/cu-ft at 60F?

At 300ft of static head the static pressure is 130 psig, assuming equal atmospheric pressure at both ends.

LOREM IPSUM > TheTurbochargedSquirrel
08/06/2018 at 18:40

I now know a little more than I did. Thank you.

Ash78, voting early and often > RamblinRover Luxury-Yacht
08/06/2018 at 18:46

Sounds good to me. Back in the day, mills would build crazy complex flumes to move water to the mill. All that mattered was volume and verical drop. It didn’t matter if you were near the creek or not.

Spanfeller is a twat > just-a-scratch
08/06/2018 at 19:38

“62.4 lbm/cu-ft at 60F”

hahah... u ppl and ur silly units.

just-a-scratch > Spanfeller is a twat
08/06/2018 at 19:44

Sorry, I’ll make this easier for you:

62.4 lbm/cu-ft = 0.0894 hundredweight/gallon [UK]

Maybe you prefer exa grains per cubic parsec?

wkiernan > Spanfeller is a twat
08/06/2018 at 19:48

M a y b e i t ’ s a H e l l o f a l o t e a s i e r t o put in a pipe line and o p e r a t e t h e generator plant three miles away than to maintain t h r e e m i l e s o f access to the base of the dam?

Berang > Spanfeller is a twat
08/06/2018 at 20:40

Honestly, dam removal is something I’m slightly fascinated by. There are a lot of early dams and powerhouses being dismantled in the U.S.

Most of them cause severe ecological problems, as well as are too antiquated to provide much power. So when the question is upgrade or demolish, many choose the latter.

Kinja'd!!!

The removal of the Elwha dam is pretty interesting. I wish they had left the powerhouse as it makes a pretty captivating landmark, but they tore everything down.

Another problem, after 80-100 years the waterways get silted up to the point where dredging isn’t an economic possibility.

Spanfeller is a twat > Berang
08/06/2018 at 20:49

Wow, I looked at pictures and it looks substantial! But Albarello’s managers chose the former: upgrade. The turbine was upgraded just two or three years ago... I just wished they also put a fish ladder too.

RamblinRover Luxury-Yacht > just-a-scratch
08/06/2018 at 21:06

Meant 62, had brain fart. Probably induced by familiar 8lb/gal back of envelope also banging around in the ol' noggin.

RamblinRover Luxury-Yacht > Ash78, voting early and often
08/06/2018 at 21:10

Now with a flume instead of a pipe, you’re all about converti ng PE to KE over the run instead of delivering stored potential to the final point - though the distinction is mostly academic. Build KE in drops, sustain KE over runs, finally deliver all converted KE instead of having PE on tap.

Eric @ opposite-lock.com > LOREM IPSUM
08/06/2018 at 23:53

It’s similar. The big dams on the Colorado river are very tall. This allows a shorter dam to absorb more energy.