7 ms·

Flying Only with the Heat of the Sun

86 points by john-doe 5y ago

ramraj07 5y ago
Isn’t almost anything that’s not powered by nuclear energy flying only with the heat of the sun with extra steps? If you include the definition of “some sun” then even nuclear energy is the same, just with a multi billion year cycle.
- phreeza 5y ago
  Just to counter your nitpick with another nitpick, geothermal is also not solar with extra steps :-) Edit: tidal power would also seem to fall into that bucket because it comes from the gravitational forces of the solar system.
  - unishark 5y ago
    Imagine the climate change problems if we used up too much gravitational energy from the solar system.
    - devenson 5y ago
      Slowing the rotation of the earth.
      - deleted 5y ago
        [deleted]
      - dimman 5y ago
        Oh noes, not longer working hours…
    - deleted 5y ago
      [deleted]
ZeroGravitas 5y ago
I find these and the low tech magazine articles fascinating, though I sometimes feel that either I'm a) falling victim to an elaborate prank, b) unknowingly supporting the output of someone's mental health issues (though I feel that about some of my best loved musical acts too). Now that's there's two sources, I'm further confused as to whether one is mocking the other, but if they are it's possibly too subtle for me to catch.
- spodek 5y ago
  I consider No and Low Tech Magazine among the best sites on the web. He's living by different values than mainstream. He loves technology and he loves sustainability. For many those loves conflict. They keep seeing attempts to make things more efficient lead to more pollution. They don't think in systems. His values are more in line with history, particularly before the industrial revolution. He finds out and shares how people did things without burning fossil fuels that we can learn from. The site has changed my life. One example: his articles on how power grids become insecure and expensive with higher uptimes, making using just renewables harder https://www.lowtechmagazine.com/2018/12/keeping-some-of-the-lights-on-redefining-energy-security.html https://www.lowtechmagazine.com/2018/12/keeping-some-of-the-..., combined with an article on fermentation in Vietnam https://www.lowtechmagazine.com/2017/02/vietnams-low-tech-fermentation-food-system-takes-advantage-of-decay.html https://www.lowtechmagazine.com/2017/02/vietnams-low-tech-fe... led me to try unplugging my fridge. Using my windowsill for cold and fermenting, my first try two winters ago, I made it three months. My next try, last winter, I started earlier and made it 6.5 months. My food was as delicious as ever and my electric charges dropped to under $2.00 per month. More importantly, I live more resiliently. If more people lived this way, large parts of the country could go with just renewables, barely any batteries, no peaker plants, no nuclear, more health, longevity, prosperity, stability, energy security. With that little energy use, I'm going to try taking my apartment off the electric grid for a few months this winter. That's living in Manhattan. I'll also start earlier as I developed more skills to store and ferment without a fridge, so starting in October or maybe September, I figure I can go 8 or 9 months without a fridge -- that is, living resiliently. To clarify, my power reduction is a side point. Divided by 7.9 billion it's a rounding error. It's the value shift from dependence to independence, from relying on burning fossil fuels to learning from my neighbors, family, and ancestors. The cause of our environmental problems isn't CO2 and plastics. They result from our behaviors, which result from our culture. He comes from a culture that doesn't cause these problems, or at least orders of magnitude less. Such solutions are practical, affordable, immediately doable and most available to those with the least resources. His philosophy focuses on improving human life, community, and Earth's ability to sustain life.
lovemenot 5y ago
At the end of the article: >> The problem remains that fully solar balloons need sunlight, and it is rare for the sky to remain unclouded for long journeys. Above 6,000 metres, it is rather rare that any cloud blocks the sun in daylight hours. This method of transport has potential for freight. Rather than black, you'd want a transparent skin or layers of skins. Focus sunlight with internal reflectors onto an engine. Usefully, waste heat is not a problem here, but valuable, when captured in the envelope. The engine should use more than just heat energy. Visible light for PV power generation. Maybe ultraviolet can be used to elecrolyse environmental water vapour to hydrogen. To provide both lift and energy storage for night time.
- m4rtink 5y ago
  Similar system (partially transparent baloon) can be used in space for the solar thermal engine concept: http://www.projectrho.com/public_html/rocket/enginelist.php#krafftsolar http://www.projectrho.com/public_html/rocket/enginelist.php#...
  - lovemenot 5y ago
    Space lacks a key drawback of the atmospheric solar concentrating balloons. Namely wind. It is difficult to point reflectors at the sun when the whole craft is slightly changing orientation all the time.
elif 5y ago
I'm no balloon expert, but it seems like they could have absorbed more heat with a translucent top. Then the solar rays would enter the chamber before hitting the black fabric and reflecting back into the chamber.. more frequencies of light, more chances to catch the heat. Like the SHGC effect observed by closing/opening curtains
tdeck 5y ago
When I was a kid at science camp we demonstrated this effect. They had a very long sausage-shaped black plastic bag that we all rand around filling up and laid out in the sun until it rose. I always assumed this strange bag was designed for such demos. In our case something happened (a person let go, a tether broke; I don't recall), and the "solar sausage" flew away completely until we could no longer see it.
Robotbeat 5y ago
Sailplanes also do this. “Gliders” get a brief mention as an aside, but it’s somewhat glossed over, but fundamentally the sport of flying depends on the same solar thermal phenomenon except instead of producing black material to absorb sunlight, sailplanes rely on existing low albedo features of the landscape to generate the solar heated air. Sailplanes air often towed to the air by powered aircraft in the US, but higher performance sailplanes usually carry their own motor for self launch (often electric) and in Europe are often winch-launched. Gravity launch (rolling down hill) and auto tow (a car pulls the sailplane into the air, usually with a pulley) are also fairly common, and the former would meet this “low tech” qualification.
- m4rtink 5y ago
  I really recommend anyone flying a glider as a passenger (in Europe this is often possible on regional air shows run by the local aeroclub) it's totally different experience to engine powered aircraft! It's much quieter than small general aviation aircraft so you can talk to the pilot without a headset, the only noise being the air flowing around the plane. The whole plane is also usually much lighter and has better visibility, not to mention being very graceful. At least for me the experience felt much more direct and elegant. And the experience of being powered pretty much directly by nature and the pilots skill in finding the invisible rising thermals is priceless! Its the perfect metagame, the pilot uses their extensive meteorogical experience to guess where the thermals are and flies there. If the guess was right you are rewarded by the sweet sweet positive altitude value on the variometer. If the guess was wrong the altitude budget is spent and you have to land and try again. And lastly, it all feels so safe! Like, really - the aircraft has no engine that can fail and is pretty much built to land on any reasonably flat field. And the pilot is trained to always look for a landing area in case they don't find thermals and have to land early. And what happens if a glider lands in a field ? Gliders have detachable wings so that they can be loaded on trailer dispatched from the airfield. In favorable conditions sometimes a tow aircraft can be dispatched to land near the glider on the same field and tow it aloft again. Really, gliders are so much different than "normal" aircraft yet so fascinating! :)
  - vitro 5y ago
aaron695 5y ago
Here's a toy one, good reviews, but fragile (have tape) and prob use once - https://www.amazon.com/TEDCO-Tedcotoys-Activity-50-foot-Balloon/dp/B00LW7WGRK https://www.amazon.com/TEDCO-Tedcotoys-Activity-50-foot-Ball... Practically perhaps you could use the principal to manage buoyancy on lighter than air... unlikely though, to much added complexity.

86 points by john-doe 5y ago

Isn’t almost anything that’s not powered by nuclear energy flying only with the heat of the sun with extra steps? If you include the definition of “some sun” then even nuclear energy is the same, just with a multi billion year cycle.

phreeza 5y ago
Just to counter your nitpick with another nitpick, geothermal is also not solar with extra steps :-) Edit: tidal power would also seem to fall into that bucket because it comes from the gravitational forces of the solar system.
- unishark 5y ago
  Imagine the climate change problems if we used up too much gravitational energy from the solar system.
  - devenson 5y ago
    Slowing the rotation of the earth.
    - deleted 5y ago
      [deleted]
    - dimman 5y ago
      Oh noes, not longer working hours…
  - deleted 5y ago
    [deleted]

ZeroGravitas 5y ago

I find these and the low tech magazine articles fascinating, though I sometimes feel that either I'm a) falling victim to an elaborate prank, b) unknowingly supporting the output of someone's mental health issues (though I feel that about some of my best loved musical acts too). Now that's there's two sources, I'm further confused as to whether one is mocking the other, but if they are it's possibly too subtle for me to catch.

spodek 5y ago
I consider No and Low Tech Magazine among the best sites on the web. He's living by different values than mainstream. He loves technology and he loves sustainability. For many those loves conflict. They keep seeing attempts to make things more efficient lead to more pollution. They don't think in systems. His values are more in line with history, particularly before the industrial revolution. He finds out and shares how people did things without burning fossil fuels that we can learn from. The site has changed my life. One example: his articles on how power grids become insecure and expensive with higher uptimes, making using just renewables harder https://www.lowtechmagazine.com/2018/12/keeping-some-of-the-lights-on-redefining-energy-security.html https://www.lowtechmagazine.com/2018/12/keeping-some-of-the-..., combined with an article on fermentation in Vietnam https://www.lowtechmagazine.com/2017/02/vietnams-low-tech-fermentation-food-system-takes-advantage-of-decay.html https://www.lowtechmagazine.com/2017/02/vietnams-low-tech-fe... led me to try unplugging my fridge. Using my windowsill for cold and fermenting, my first try two winters ago, I made it three months. My next try, last winter, I started earlier and made it 6.5 months. My food was as delicious as ever and my electric charges dropped to under $2.00 per month. More importantly, I live more resiliently. If more people lived this way, large parts of the country could go with just renewables, barely any batteries, no peaker plants, no nuclear, more health, longevity, prosperity, stability, energy security. With that little energy use, I'm going to try taking my apartment off the electric grid for a few months this winter. That's living in Manhattan. I'll also start earlier as I developed more skills to store and ferment without a fridge, so starting in October or maybe September, I figure I can go 8 or 9 months without a fridge -- that is, living resiliently. To clarify, my power reduction is a side point. Divided by 7.9 billion it's a rounding error. It's the value shift from dependence to independence, from relying on burning fossil fuels to learning from my neighbors, family, and ancestors. The cause of our environmental problems isn't CO2 and plastics. They result from our behaviors, which result from our culture. He comes from a culture that doesn't cause these problems, or at least orders of magnitude less. Such solutions are practical, affordable, immediately doable and most available to those with the least resources. His philosophy focuses on improving human life, community, and Earth's ability to sustain life.

lovemenot 5y ago

At the end of the article: >> The problem remains that fully solar balloons need sunlight, and it is rare for the sky to remain unclouded for long journeys. Above 6,000 metres, it is rather rare that any cloud blocks the sun in daylight hours. This method of transport has potential for freight. Rather than black, you'd want a transparent skin or layers of skins. Focus sunlight with internal reflectors onto an engine. Usefully, waste heat is not a problem here, but valuable, when captured in the envelope. The engine should use more than just heat energy. Visible light for PV power generation. Maybe ultraviolet can be used to elecrolyse environmental water vapour to hydrogen. To provide both lift and energy storage for night time.

m4rtink 5y ago
Similar system (partially transparent baloon) can be used in space for the solar thermal engine concept: http://www.projectrho.com/public_html/rocket/enginelist.php#krafftsolar http://www.projectrho.com/public_html/rocket/enginelist.php#...
- lovemenot 5y ago
  Space lacks a key drawback of the atmospheric solar concentrating balloons. Namely wind. It is difficult to point reflectors at the sun when the whole craft is slightly changing orientation all the time.

elif 5y ago

I'm no balloon expert, but it seems like they could have absorbed more heat with a translucent top. Then the solar rays would enter the chamber before hitting the black fabric and reflecting back into the chamber.. more frequencies of light, more chances to catch the heat. Like the SHGC effect observed by closing/opening curtains

tdeck 5y ago

When I was a kid at science camp we demonstrated this effect. They had a very long sausage-shaped black plastic bag that we all rand around filling up and laid out in the sun until it rose. I always assumed this strange bag was designed for such demos. In our case something happened (a person let go, a tether broke; I don't recall), and the "solar sausage" flew away completely until we could no longer see it.

Robotbeat 5y ago

Sailplanes also do this. “Gliders” get a brief mention as an aside, but it’s somewhat glossed over, but fundamentally the sport of flying depends on the same solar thermal phenomenon except instead of producing black material to absorb sunlight, sailplanes rely on existing low albedo features of the landscape to generate the solar heated air. Sailplanes air often towed to the air by powered aircraft in the US, but higher performance sailplanes usually carry their own motor for self launch (often electric) and in Europe are often winch-launched. Gravity launch (rolling down hill) and auto tow (a car pulls the sailplane into the air, usually with a pulley) are also fairly common, and the former would meet this “low tech” qualification.

m4rtink 5y ago
I really recommend anyone flying a glider as a passenger (in Europe this is often possible on regional air shows run by the local aeroclub) it's totally different experience to engine powered aircraft! It's much quieter than small general aviation aircraft so you can talk to the pilot without a headset, the only noise being the air flowing around the plane. The whole plane is also usually much lighter and has better visibility, not to mention being very graceful. At least for me the experience felt much more direct and elegant. And the experience of being powered pretty much directly by nature and the pilots skill in finding the invisible rising thermals is priceless! Its the perfect metagame, the pilot uses their extensive meteorogical experience to guess where the thermals are and flies there. If the guess was right you are rewarded by the sweet sweet positive altitude value on the variometer. If the guess was wrong the altitude budget is spent and you have to land and try again. And lastly, it all feels so safe! Like, really - the aircraft has no engine that can fail and is pretty much built to land on any reasonably flat field. And the pilot is trained to always look for a landing area in case they don't find thermals and have to land early. And what happens if a glider lands in a field ? Gliders have detachable wings so that they can be loaded on trailer dispatched from the airfield. In favorable conditions sometimes a tow aircraft can be dispatched to land near the glider on the same field and tow it aloft again. Really, gliders are so much different than "normal" aircraft yet so fascinating! :)
- vitro 5y ago

aaron695 5y ago

Here's a toy one, good reviews, but fragile (have tape) and prob use once - https://www.amazon.com/TEDCO-Tedcotoys-Activity-50-foot-Balloon/dp/B00LW7WGRK https://www.amazon.com/TEDCO-Tedcotoys-Activity-50-foot-Ball... Practically perhaps you could use the principal to manage buoyancy on lighter than air... unlikely though, to much added complexity.