Post Ajnv1Cl9Dik4JdwBAe by divVerent@blob.cat
(DIR) More posts by divVerent@blob.cat
(DIR) Post #Ajnv1BOQIiyE4sIW6y by Toastie@journa.host
2024-07-10T22:37:33Z
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Real #climate question: if these can be gravity powered, why can't a home generator be gravity powered?
(DIR) Post #Ajnv1Cl9Dik4JdwBAe by divVerent@blob.cat
2024-07-11T00:27:02.948928Z
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@Toastie Literally the only reason is the amount of energy needed.A typical smartphone battery takes 30 kJ to be fully charged. That clock uses way less than that.My air rifle shoots projectiles with about 50 Joules. After shooting 24 rounds with it - 1200 Joules - I need to pump it back up for 5 minutes. So if the same tech were used for smartphones, just charging one phone from 0 to 100 would take me about 2 hours.Or, you know 1 J is 1 Nm, and the energy to move 1 kg 1 meter up is about 9.81 J. So 30 kJ is e.g. moving 3000 kg 1 meter up. Or maybe 6 kg 500 meters up. Basically you could thus charge your phone by carrying a backpack up a small mountain. This too gets into the ballpark of 2 hours.And this is just to charge a phone. Imagine the energy needed to cook food. Even if you just needed 1000W for 5 minutes - that is 300 kJ now. 10 times the energy to charge a phone.So it is not that this method has no applications. It works perfectly fine for a clock, even mechanical one, or a LED flashlight, or a gun, or to fill a tire, maybe even for a low powered smartphone or laptop.But that is the limit. You cannot cook from muscle power alone, or heat your home.Now there is another application: if you want gravity only for energy storage, but you do not care where the energy comes from - pump water power plants are the strongest and biggest "batteries" we have in the world. You pump water up when you have excess energy available, and let it flow down and drive a water power plant when you need extra energy. This can definitely be part of making solar or wind power suffice for us all.
(DIR) Post #Ajnv1DKb5v6A5aWUQS by Toastie@journa.host
2024-07-10T23:00:40Z
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What if everyone pushed a boulder up a hill everyday to power their fridge
(DIR) Post #Ajnv1F06t3tnGcx9lo by Toastie@journa.host
2024-07-10T23:01:23Z
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You can just mail me my nobel peace science prize
(DIR) Post #AjnxWCXGIpjEVTLmjI by Toastie@journa.host
2024-07-11T00:28:55Z
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@divVerent Thanks for that!
(DIR) Post #AjnxWDcyF5tBtT1rGa by divVerent@blob.cat
2024-07-11T00:55:05.074606Z
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@Toastie Sure.I forgot to mention that all those methods I mentioned are not super efficient. I do not know how much power the pump and air rifle lose, but if I carry 6 kg up a mountain, I must also carry myself up which is definitely some waste. Instead of walking back down, I could maybe stand on some kind of "lift" that carries me down while using the energy from having carried my own body weight up for some extra work.So there is definitely one extra order of magnitude to win there. A typical human can sustain a power output of about 300W for longer periods of time. That is thus the theoretical limit, excluding any efficiency losses. Gets into the ballpark of maybe enough for cooking, but definitely not for heating.How to get even more? Have slaves... no, bad idea. More seriously, let large animals do the work. And that is precisely what people did in the medieval times. Basically use them as machines to convert energy stored in food into something usable.Obviously though, energy coming from humans or animals too is not necessarily free or climate neutral. One will also need to consider the food, its production, and any waste produced by the human or animal, including of course CO2.So it all isn't easy to be climate neutral...
(DIR) Post #Ajny60nJQveWW7vwxc by Toastie@journa.host
2024-07-11T00:57:43Z
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@divVerent What we need to do is harness the power of the moon's orbit.Let the moon do the work.
(DIR) Post #Ajny61mdkui1aKcvYG by divVerent@blob.cat
2024-07-11T01:01:32.694596Z
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@Toastie This exists and is called a tidal power plant.By using this excessively, we may in the long term interfere with the moon's orbit, but there is plenty of energy stored there so this is not gonna run out anytime soon.