Waterless high-density hydro stores more energy with less elevation | Hacker News Reader

Waterless high-density hydro stores more energy with less elevation

newatlas.com

The article says you get the same energy for 40% of the volume and 40% of the height. That’s not true, though. You can save 60% on one of those variables but not both. Otherwise you lose and extra 60%.

That density looks too high to be true. There is a list of liquids with a density >= 2 times the density of water in https://en.wikipedia.org/wiki/Heavy_liquid and most of them have bromide and don't look very environmental friendly. Also, none of them are made using a powder mixed with water, so this claim is very strange.

Usual solutions with water get up to 1.5 . I can't find any that is close to 2 (nor 2.5). Perhaps a sugar with a lot of chlorines? Like https://en.wikipedia.org/wiki/Sucralose but IIUC the solutions have also a density < 2 ... Very strange.

Also, it would be interesting to know the viscosity. Pumping high viscosity goop is difficult.

From https://www.rheenergise.com/news

> Consortium Plan To Build & Operate Scotland's First Low Carbon, Energy Efficient, Soil-Free Vertical Farms In The Central Belt

I'm a vertical farm skeptic, so the list of projects is very suspicious.

That density looks too high to be true.

This magic powder actually causes water to shrink with almost no increase in viscosity.

Put in 2.5 liters/gallons, add some powder and presto --- you only get 1 back.

This is not as inconceivable as you make it sound if there's chemical reaction involved

The really inconceivable part is that this high density fluid will be almost as easy to pump as water and just as environmentally friendly.

There is no too much room between water molecules to compress them to double the density. https://www.youtube.com/watch?v=zRUFzJrDtq0

Even in a chemical reaction the volume of the atoms doesn't change too much. You must add some heavier atoms to get more density. All normal liquids like water, oil, alcohol, ... that are made of hydrogen, carbon and oxygen have a density of ~1. Do you know a chemical reaction that can do that?

A sibling comment says that they are apparently using some kind of drilling mud, that is a mix of compound that have heavier atoms like calcium, aluminium, magnesium, silicon.

18 days ago someone dug up the patent on this thread and suggested it was essentially mud:

https://news.ycombinator.com/item?id=37193096

Looks like someone found a new use for barium based drilling mud from the oil & gas industry

Better idea --- just use a big ole block of high density concrete suspended on cables and avoid all the friction/energy losses trying to pump this high density goop.

https://gravitricity.com/#fast-long-life-energy-storage

Very dubious that that's a better idea.

Very dubious that it's not.

Pumping an ultra dense, high viscosity fluid comes with significant energy losses due to friction.

Pumps/turbines have additional loses and are typically less efficient than direct mechanical gear drive.

You can make a shaft in more locations than you can find a hill.

The mud will be much cheaper than concrete. The scheme you propose will either require complex machinery for switching hoists/generators between concrete blocks, or large numbers of hoists/generators. PHES easily shares one or a small number of pumps/turbines among the entire mass of liquid.

They state: "R19 has a viscosity of ~20cP, comparable to milk." So, not that viscous.

Density and viscosity are typically related.

Color me skeptical that a fluid made from mostly water can have 2.5 times the density of water without a substantial increase in viscosity.

Effectively, you're talking the density of concrete and the viscosity of milk. Must be some new alien chemistry/physics involved here.

If you have to resort to "they're just lying because" as an argument, you should probably just shut up.

Extraordinary claims require extraordinary proof.

But even given the benefit of the doubt, there is little advantage over alternatives if you don't just happen to have lots of natural hills/land readily available.

A block of concrete has about 2.5 times the density of water and creating one doesn't require any magic chemistry. The land required for a "gravity battery" is only slightly larger than the concrete block itself.

https://futurism.com/the-byte/company-builds-facility-lifts-...

For reference, your quote is from https://www.rheenergise.com/faq

But the viscosity of water is approximately .9cP [1] and the viscosity of milk is between 1cP (hot) and 2cP (cold) [2]. From that table, 20cP is closer to cream from milk. That error is another red flag.

[1] https://en.wikipedia.org/wiki/Water

[2] https://www.michael-smith-engineers.co.uk/resources/useful-i... [It's very strange that they don't include water!]

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