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Drones will fly for days with new photovoltaic engine

techxplore.com

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Re: Drones will fly for days with new photovoltaic engine

#21

Post by IanCal »

walrus01 wrote: post #12
dvh wrote: post #5

Earlier quoted context omitted.

DJI Phantom 3 is 0.3m wide and needs 120W to fly. Solar radiation at surface is 1000W/m2. 0.3m 0.3m 1000 = 90W at 100% efficiency. They claim 29% eficiency* (compared to regular 23%) which is only 26W out of 120W in ideal circumstances, realistically it would be maybe 1/3 of it. It will not fly. You can safely ignore ALL articles about breakthroughs in solar cell efficiency and look only at what is sold in shops beca…

I essentially second everything that the person above is saying. There are an endless number of press releases and public relations bullshit articles put out by people who have some new "breakthrough" in photovoltaics. Whether it's special weird cells, or flower shaped ground mount things, or whatever. What I believe in, is what I can pull out my visa card and buy right now. And at the moment, here's what that looks…

The article is not about solar cells though. It's about thermophotovoltalics, where you'd use a high temperature heat source.

Re: Drones will fly for days with new photovoltaic engine

#22

Post by wumms »

IanCal wrote: post #14
wumms wrote: post #9

Earlier quoted context omitted.

Yes, the max. energy from sunlight on earth hitting an envelope should be around 20-30 Watts (at 100% efficiency). Also, the reported 29.1% efficiency have been reached at a temperature of 1,207 °C.

This isn't about sunlight, but about putting this with a furnace or something else generating heat.

Yes, the original article is about thermophotovoltaics.

Regarding the article posted here (and since a drone with a furnace is not feasible) I went with solar.

Re: Drones will fly for days with new photovoltaic engine

#23

Post by IanCal »

People seem to be misinterpreting this a lot.

This is not about solar cells. This is about thermophotovoltalics, and the application here is using a burning fuel source to generate electricity.

The "drone" the paper talks about seems to be a reference to another paper on unmanned sea vehicles though. Edit - to be fair the flying drone part is from the corresponding author.

Re: Drones will fly for days with new photovoltaic engine

#24

Post by IanCal »

wumms wrote: post #22
IanCal wrote: post #14

Earlier quoted context omitted.

This isn't about sunlight, but about putting this with a furnace or something else generating heat.

Yes, the original article is about thermophotovoltaics. Regarding the article posted here (and since a drone with a furnace is not feasible) I went with solar.

The corresponding author to be fair did say unmanned aerial vehicles.

Re: Drones will fly for days with new photovoltaic engine

#25

Post by PakG1 »

agumonkey wrote: post #17

Surprisingly never heard of Thermophotovoltaics. Here's a simple diagram https://proxy.duckduckgo.com/iu/?u=http%3A%2F%2Fanilyuksel.f... It seems like 'impedance matched' photovoltaics.. very interesting.

Hah, now I have a vision of one of these things hooked up to every air conditioner in the world to claw back some of the electricity that the air conditioner uses. I imagine the heat would need to be a bit more than what an air conditioner generates though, but I know nothing about the topic, so who knows.

Re: Drones will fly for days with new photovoltaic engine

#26

Post by Animats »

wumms wrote: post #9
zaarn wrote: post #4

It reads a bit overhyped, considering they claim to power a house with a generator the size of an envelope; that's a hard no since there is a limit on how much energy hits every square meter and it's not THAT much.

Yes, the max. energy from sunlight on earth hitting an envelope should be around 20-30 Watts (at 100% efficiency). Also, the reported 29.1% efficiency have been reached at a temperature of 1,207 °C.

Also, the reported 29.1% efficiency have been reached at a temperature of 1,207 °C.

Another 12% and they can compete with a standard steam turbogenerator.

Re: Drones will fly for days with new photovoltaic engine

#27

Post by taneq »

Animats wrote: post #26
wumms wrote: post #9

Earlier quoted context omitted.

Yes, the max. energy from sunlight on earth hitting an envelope should be around 20-30 Watts (at 100% efficiency). Also, the reported 29.1% efficiency have been reached at a temperature of 1,207 °C.

Also, the reported 29.1% efficiency have been reached at a temperature of 1,207 °C. Another 12% and they can compete with a standard steam turbogenerator.

Wouldn't you slap this on top of a steam boiler to get the best of both worlds, though?

Re: Drones will fly for days with new photovoltaic engine

#28

Post by wumms »

IanCal wrote: post #24
wumms wrote: post #22

Earlier quoted context omitted.

Yes, the original article is about thermophotovoltaics. Regarding the article posted here (and since a drone with a furnace is not feasible) I went with solar.

The corresponding author to be fair did say unmanned aerial vehicles.

True, though it is combined (in the article) with a maximum power consumption: "those that require as little as 100 watts, [such as] a lightweight unmanned aerial vehicle"

The original paper says "unmanned vehicles" (no aerial) and has a reference [0] to "unmanned undersea vehicles".

[0] https://www.pnas.org/content/early/2019/07/15/1903001116#ref...

Re: Drones will fly for days with new photovoltaic engine

#29

Post by amirhirsch »

ajuc wrote: post #19
EGreg wrote: post #2

So what does this mean, we will be able to have drones flying continuously and getting energy from the sun?

We already have drones with wings that are capable of that, or close to it. This would make them more efficient. https://www.youtube.com/watch?v=8m4_NpTQn0E For quadcopters and similar I doubt it will be enough.

I’ve seen reports of thin film organic solar cells that produce >1 watts per gram of material. A quadcopter motor can generate multiple grams per watt of power. You can today go and buy 100W from a 3.3lb panel, which is like half way there and not even trying. I’m guessing it’s probably possible to make a quadcopter that can hover indefinitely in the sun.
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