4 ms·

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

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

pfdietz 3y ago
Very dubious that that's a better idea.
- jqpabc123 3y ago
  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.
  - pfdietz 3y ago
    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.
    - jqpabc123 3y ago
      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.
      - pfdietz 3y ago
        If you have to resort to "they're just lying because" as an argument, you should probably just shut up.
        jqpabc123 3y ago
        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-lowers-bricks-store-energy https://futurism.com/the-byte/company-builds-facility-lifts-...
    - gus_massa 3y ago
      For reference, your quote is from https://www.rheenergise.com/faq 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 https://en.wikipedia.org/wiki/Water [2] https://www.michael-smith-engineers.co.uk/resources/useful-info/approximate-viscosities-of-common-liquids-by-type https://www.michael-smith-engineers.co.uk/resources/useful-i... [It's very strange that they don't include water!]
  - deleted 3y ago
    [deleted]

pfdietz 3y ago

Very dubious that that's a better idea.

jqpabc123 3y ago
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.
- pfdietz 3y ago
  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.
  - jqpabc123 3y ago
    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.
    - pfdietz 3y ago
      If you have to resort to "they're just lying because" as an argument, you should probably just shut up.
      - jqpabc123 3y ago
        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-lowers-bricks-store-energy https://futurism.com/the-byte/company-builds-facility-lifts-...
  - gus_massa 3y ago
    For reference, your quote is from https://www.rheenergise.com/faq 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 https://en.wikipedia.org/wiki/Water [2] https://www.michael-smith-engineers.co.uk/resources/useful-info/approximate-viscosities-of-common-liquids-by-type https://www.michael-smith-engineers.co.uk/resources/useful-i... [It's very strange that they don't include water!]
- deleted 3y ago
  [deleted]