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Comment by adrianmonk | Hacker News Reader

> heavy liquid. They typically go for $100-$1000/kg

This company has their own proprietary heavy fluid called R-19. Their formula isn't public, but presumably they understand the success of their company depends on it being affordable.

> No idea what the article is talking about wrt being able to utilize lower heights

It means that, if pumped storage starts to look worth it to you (given budget, etc.) with tanks of size V and a height difference of H, then with their system it might be worth it if the tallest hill available to you is H/2.5.

Or you can keep the height the same and reduce the volume. Or keep both the same and increase the storage. The point is that they claim to offer a better trade-off.

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> This company has their own proprietary heavy fluid called R-19. Their formula isn't public, but presumably they understand the success of their company depends on it being affordable.

That assumes they plan to ever deliver anything real. There are very few substances cheaper per unit mass than water, and I would not take on faith that something that isn't even being mass produced yet could ever possibly compete.

> It means that, if pumped storage starts to look worth it to you (given budget, etc.) with tanks of size V and a height difference of H, then with their system it might be worth it if the tallest hill available to you is H/2.5.

That's not how turbines work. Pressure head is independent of volume.

> Or you can keep the height the same and reduce the volume. Or keep both the same and increase the storage. The point is that they claim to offer a better trade-off.

And I am saying that I do not believe their claim that they offer a better trade off.

> That's not how turbines work. Pressure head is independent of volume.

I'm not talking about pressure head. I'm talking about energy storage. If everything is held constant (reservoir volume, height difference) but the density of the fluid changes, then the energy stored changes. Because gravitational potential energy is E = mgh. And m = volume * density.

But since you mentioned pressure head, if volume changes, it doesn't affect pressure. But if the fluid density changes (and all else is equal), then that DOES affect pressure. That's why if you measure pressure in mmHg you will get a different number than if you measure it in mmH2O. So if you took a pumped hydro storage system and drained the water out and replaced it with denser fluid, the fluid would press harder on the turbine.

They claim they have a fluid. The patent says "minerals", water, and "surfactant." Translation: mud/sand.

I can't help but notice that the name they're using is the same as an insulation material; seems almost purposeful to make looking up anything about it very difficult.

I don't think they have anything and this is just a patent troll or someone trying to pull a fast one on investors. I'd be willing to bet they have a long list of reasons why they can't come up with demonstration unit that is room or building-sized...

It could be something like bentonite/baryte or similar drlling muds:

https://en.wikipedia.org/wiki/Drilling_mud

Drilling mud, however, needs to be at least somewhat viscous, so it will carry rock fragments from the drilling back to the surface.

Sure, but it depends also on the kind of drilling and of the terrain that is drilled, drilling mud is used also when drilling with buckets large holes, in those cases the use is only that of avoiding the collapse of the walls of the bore.

The generic idea behind these supposedly high efficiency reservoirs is to have something that is at the same time liquid enough and much heavier than water, most probably the actual formulation will be a compromise.

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