Somewhat different, but this reminds me of an approach that uses temperature gradients in the ocean to power a heat engine. https://en.wikipedia.org/wiki/Ocean_thermal_energy_conversio...
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Mechanical power generation using Earth's ambient radiation
21–30 of 70 posts
Re: Mechanical power generation using Earth's ambient radiation
#22Somewhat different, but this reminds me of an approach that uses temperature gradients in the ocean to power a heat engine. https://en.wikipedia.org/wiki/Ocean_thermal_energy_conversio...
OTECs are amazing, and step 1 of "The Millennial Project: Colonizing the galaxy in eight easy steps"[0] [0]: https://en.wikipedia.org/wiki/The_Millennial_Project There's a shore-based research OTEC in Hawaii, but the best is a floating, closed-loop OTEC in the ocean.
Interesting link.
I would think step 7 would come before step 6 though.
I thought about this for a few minutes and can't come with a reason otherwise.
Re: Mechanical power generation using Earth's ambient radiation
#23DIY radiative cooling paint from YouTuber NightHawkInLight - https://www.youtube.com/watch?v=N3bJnKmeNJY&list=PL1a2HkcVbm... It has pretty impressive performance. Tech Ingredients did one or two vids as well - https://www.youtube.com/watch?v=dNs_kNilSjk Was thinking of whipping up a batch for my rv.
This concept is used all over India to cool down homes that are on the top floors.
https://www.amazon.in/EXCEL-CoolCoat%C2%AE-Reflective-Coatin...
Basically, have a highly reflective white coat on your roof, to reduce temperatures by about 3 Degrees Celsius.
Almost all homes in Urban India are made from concrete and bricks, which can hold a lot of heat.
I myself have been in houses that use this to cover only some rooms of the house (mainly the bedroom), and the temperature difference is definitely noticeable. It also makes the room livable in the extreme hot summers in India.
Re: Mechanical power generation using Earth's ambient radiation
#24Earlier quoted context omitted.
OTECs are amazing, and step 1 of "The Millennial Project: Colonizing the galaxy in eight easy steps"[0] [0]: https://en.wikipedia.org/wiki/The_Millennial_Project There's a shore-based research OTEC in Hawaii, but the best is a floating, closed-loop OTEC in the ocean.
wiki article states "Up to 10,000 TWh/yr of power could be generated from OTEC without affecting the ocean's thermal structure". which converts to about 500GW which... isn't that much
This can't be correct.
10,000 TWh/y = 1e+7 GWh/y, divide it by 365.25 days/y to produce daily output of 27,379 GWh/day, then by 24 h/day to get pure power of 1,141 GW. It's still more than a terawatt, three orders of magnitude larger than the largest nuclear reactors.
Re: Mechanical power generation using Earth's ambient radiation
#25In one of the later Foundation series books, Isaac Asimov had a whole world run on this.
Which book? Which world? I don't remember this, but it has been a few years.
Re: Mechanical power generation using Earth's ambient radiation
#26Earlier quoted context omitted.
wiki article states "Up to 10,000 TWh/yr of power could be generated from OTEC without affecting the ocean's thermal structure". which converts to about 500GW which... isn't that much
This can't be correct. 10,000 TWh/y = 1e+7 GWh/y, divide it by 365.25 days/y to produce daily output of 27,379 GWh/day, then by 24 h/day to get pure power of 1,141 GW. It's still more than a terawatt, three orders of magnitude larger than the largest nuclear reactors.
oops. yes. still not that much though. i mean it's a lot but it's "one more large industrialized country" a lot not "kardashev 2" a lot
Re: Mechanical power generation using Earth's ambient radiation
#27Since we're talking about stirling engines, I've always wondered how using geothermal heat for a larger stirling engine would work. https://youtu.be/duuk_r--lqU?t=99 Even though the video uses the sun to heat the oil, I would think it would be feasible to use geothermal heat instead.
Re: Mechanical power generation using Earth's ambient radiation
#28Since we're talking about stirling engines, I've always wondered how using geothermal heat for a larger stirling engine would work. https://youtu.be/duuk_r--lqU?t=99 Even though the video uses the sun to heat the oil, I would think it would be feasible to use geothermal heat instead.
You boil water :)
Re: Mechanical power generation using Earth's ambient radiation
#29Not an engine, but some friends of mine got a mylar sheet that's black on one side and reflective on the other. We tried it out in the desert tied onto trees/vehicles. You put the shiny side down, so the hot IR radiation of the earth is reflected away, and the black side sees the extremely cold (in IR) desert sky. If you put a little hole in the middle and put a bucket under it, you get a fair bit of water, because the mylar sheet gets about 20 degrees C below ambient and a lot of water condenses on it. (even in the desert)
Re: Mechanical power generation using Earth's ambient radiation
#30> 400 milliwatts per square meter
About two orders of magnitude weaker than solar panels, even over 24 hours.
E = (T2-T1) / T2