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> But you don't see dust accumulating indefinitely on roofs, do you? I do, actually.

by 2143 4y ago

henearkr 4y ago
Ok, my bad then. In which region? I've never seen people shoveling off kilos of dust from their roof like they would do for e.g. snow. For example the wind bringing Sahara dust to Southern Europe only leaves a thin layer of dust, it would never reach anywhere close to 0.2 mm. That still leaves a lot of light going through, so maybe it becomes my hypothetical 20% (maybe roughly the same as a very cloudy weather). Precision: I'm speaking of a sloppy roof, of course, not a flat one.
- deleted 4y ago
  [deleted]
- 2143 4y ago
  > In which region? South Asia. > I've never seen people shoveling off kilos of dust from their roof like they would do for e.g. snow. And I've never seen people shoveling off snow from their roof. Because it doesn't snow here. Doesn't mean it doesn't snow anywhere in the world. Same thing with the dust. You have snow. We have dust. You're lucky to live in a place that's not dusty. Tangential anecdote: the replacement intervals of air filters of cars (including those that are sold in both USA and here) are drastically different. Over here for most cars the filters should be changed at around 10000 km. In USA it's more like 24000 km (for especially dusty conditions) to 48000 km for those same cars. (I picked USA because it's a random developed country. I do not assume you're from there.) How about indoors? We sweep/vaccum away plenty of dust. Do you people not have to do that? > That still leaves a lot of light going through, so maybe it becomes my hypothetical 20% (maybe roughly the same as a very cloudy weather). We don't have to speculate; there's studies on this. I'm posting a couple of links I skimmed through: 1. https://news.mit.edu/2022/solar-panels-dust-magnets-0311 https://news.mit.edu/2022/solar-panels-dust-magnets-0311 2. https://www.nrel.gov/news/features/2021/scientists-studying-solar-try-solving-a-dusty-problem.html https://www.nrel.gov/news/features/2021/scientists-studying-... From the 2nd link: "The energy lost annually from soiling amounts to as much as 7% in parts of the United States to as high as 50% in the Middle East." Middle-east is all desert, and there's as much as 50% energy loss there.
  - henearkr 4y ago
    Thanks a lot for the references! But do you realize that I was speaking of 20% output and not of a 20% reduction (i.e. 80% output) which makes my speculation worse than what it is actually in the Middle-East? In my opinion, on a huge solar grid, 50% is still pretty much helpful (solar is roughly forever free energy, modulo the maintenance cost). > How about indoors? We sweep/vaccum away plenty of dust. Do you people not have to do that? We're speaking of enough dust hanging on a smooth sloppy surface (not a floor, but a plane with an angle) and thick enough to block more than 80% of the light (for dust, that makes very thick).

> But you don't see dust accumulating indefinitely on roofs, do you? I do, actually.

by 2143 4y ago

> But you don't see dust accumulating indefinitely on roofs, do you? I do, actually.

Ok, my bad then. In which region? I've never seen people shoveling off kilos of dust from their roof like they would do for e.g. snow. For example the wind bringing Sahara dust to Southern Europe only leaves a thin layer of dust, it would never reach anywhere close to 0.2 mm. That still leaves a lot of light going through, so maybe it becomes my hypothetical 20% (maybe roughly the same as a very cloudy weather). Precision: I'm speaking of a sloppy roof, of course, not a flat one.

deleted 4y ago
[deleted]
2143 4y ago
> In which region? South Asia. > I've never seen people shoveling off kilos of dust from their roof like they would do for e.g. snow. And I've never seen people shoveling off snow from their roof. Because it doesn't snow here. Doesn't mean it doesn't snow anywhere in the world. Same thing with the dust. You have snow. We have dust. You're lucky to live in a place that's not dusty. Tangential anecdote: the replacement intervals of air filters of cars (including those that are sold in both USA and here) are drastically different. Over here for most cars the filters should be changed at around 10000 km. In USA it's more like 24000 km (for especially dusty conditions) to 48000 km for those same cars. (I picked USA because it's a random developed country. I do not assume you're from there.) How about indoors? We sweep/vaccum away plenty of dust. Do you people not have to do that? > That still leaves a lot of light going through, so maybe it becomes my hypothetical 20% (maybe roughly the same as a very cloudy weather). We don't have to speculate; there's studies on this. I'm posting a couple of links I skimmed through: 1. https://news.mit.edu/2022/solar-panels-dust-magnets-0311 https://news.mit.edu/2022/solar-panels-dust-magnets-0311 2. https://www.nrel.gov/news/features/2021/scientists-studying-solar-try-solving-a-dusty-problem.html https://www.nrel.gov/news/features/2021/scientists-studying-... From the 2nd link: "The energy lost annually from soiling amounts to as much as 7% in parts of the United States to as high as 50% in the Middle East." Middle-east is all desert, and there's as much as 50% energy loss there.
- henearkr 4y ago
  Thanks a lot for the references! But do you realize that I was speaking of 20% output and not of a 20% reduction (i.e. 80% output) which makes my speculation worse than what it is actually in the Middle-East? In my opinion, on a huge solar grid, 50% is still pretty much helpful (solar is roughly forever free energy, modulo the maintenance cost). > How about indoors? We sweep/vaccum away plenty of dust. Do you people not have to do that? We're speaking of enough dust hanging on a smooth sloppy surface (not a floor, but a plane with an angle) and thick enough to block more than 80% of the light (for dust, that makes very thick).