• nomecks@lemmy.wtf
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      3 days ago

      You’re in luck. Supercritical CO2 turbines are a thing now, and they’re way more efficient because they don’t involve a phase change.

      • Monument@lemmy.sdf.org
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        3 days ago

        It’s funny (in a sad and sardonic sense) - I pay attention to the energy industry and the outcry over data centers has got me watching these generators closely. If they deliver on their promises, they could represent a great way to deliver on mirror-based solar reactors in areas with limited water resources. (And to recapture and use waste heat from the servers of data centers.)

        Society is on the precipice of investing a lot into increasing energy generation for data centers that have to be near the same sorts of resources that people need - fresh water, environs conductive to generating power, stable (enough) climates. But this technology is arriving/set to reach adoption just in time for this boom-bust cycle. All those data centers in populated areas already have a timer ticking for when the shell corps have their rugs pulled.

        • Tlaloc_Temporal@lemmy.ca
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          3 days ago

          Unfortunately, there’s no way to get energy out of waste heat that won’t be spent pushing that heat a little harder. Already a significant amount of energy is spent cooling data centers, any attempts at energy recapture will just make that cooling harder.

          The best we can do is something like district heating, because heat pumps can get over 100% effective efficiency.

          • Monument@lemmy.sdf.org
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            2 days ago

            The energy needed for phase change for supercritical CO2 is substantially lower than steam.

            There’s more wiggle room. My understanding is that similar to heat pumps, they can build systems with different optimal temperatures, and even daisy chain them together. They’ll never make a perpetual motion machine, but they can waste less energy.

            • Tlaloc_Temporal@lemmy.ca
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              13 hours ago

              True, we can optimize the cycles more. Like double expansion piston engines, or that crazy proposal for a hydrid steam-mercury super high pressure power plant.

      • Bluewing@lemmy.world
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        3 days ago

        At some point you are going to need steam to spin a turbine to generate enough energy to compress the CO2.

        • anton@lemmy.blahaj.zone
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          19 hours ago

          But that’s part of the bootstrapping process. The same way you need power to run the crucibles in a PV factory or to lift the wind turbine part by crane.

    • FiskFisk33@startrek.website
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      3 days ago

      Solar cells, technically.

      boiling water systems have a thermal efficiency of ~40% Solar cells are closer to 45% efficient

        • BussyCat@lemmy.world
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          3 days ago

          They would melt, but we do also have gamma voltaics which can use the gamma radiation from fission and fusion to generate electricity they just have an atrocious efficiency

      • Rivalarrival@lemmy.today
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        3 days ago

        Doesn’t seem particularly efficient to me… The sun burns hundreds of millions of tons of hydrogen every second. The amount of released energy we actually put to use is indistinguishable from zero, not 45%.

        • ilinamorato@lemmy.world
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          3 days ago

          I mean, that’s like pointing out that a coal plant isn’t very efficient because it doesn’t burn all the coal on Earth at once.

        • FiskFisk33@startrek.website
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          3 days ago

          If we put it like that, every other energy source on earth begins that way and adds at least one conversion step.

          … except for fusion of course.

          • Rivalarrival@lemmy.today
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            2 days ago

            Exactly.

            Nuclear plants are probably the least efficient, because they required all that fusion energy inside earlier stars to build hydrogen into uranium, and we can only extract a tiny portion of that trapped fusion energy through fission.