6 ms·

New concentrator could help solar panels capture more sunlight without tracking

73 points by sohkamyung 4y ago

2Gkashmiri 4y ago
Cool. Imagine when it can be installed on existing panels. I have a 5.5 kW panel system that gets me around 30kwh daily in summers which is probably the best l can get on a stationary roof east facing. They did not give any specifics as to the improvement in efficiency, is it 10%?
bell-cot 4y ago
I get the feeling that generating (say) 10% more power by adding these fancy bits of optics to a set of solar cells would cost far more than (getting the same improvement by) installing 10% more optics-free solar cells.
- simonebrunozzi 4y ago
  Always been the main problem with concentrated solar.
- h0l0cube 4y ago
  > 10% more power by adding these fancy bits of optics to a set of solar cells would cost far more than (getting the same improvement by) installing 10% more optics-free solar cells Surely if you're comparing against fixed solar panels, then it would be more than 10%? For tracked solar panels, costlier installation and maintenance would be traded off with efficiency of the prismatic optics and degradation of materials. Economies of scale might favor the optics if it's cheap enough to manufacture (less components, cheap materials etc.)
  - bell-cot 4y ago
    If the new optics give X% more power, they compete against "just buy X% more solar panels". (My original "(say)", in front of the "10%", was meant to indicate that the number was arbitrary.) > Economies of scale might favor the optics if it's cheap enough... - Quite true. But note that the article describes the inventor of the new optical system as "assistant professor in astronautics and spacecraft engineering". That certainly suggests cost-insensitive, performance-critical applications - such as cubesats.
    - h0l0cube 4y ago
      You're probably right. Given they seem to be using glass, I'd say it's both too heavy for space (?), and too costly for earth. I guess I'm hoping they take this technique to cheaper easier materials so I can slap this on top of a van and get decent power in a variety of different conditions.
- KleerKut 4y ago
  Agreed. Unless you have serious space constraints, more cheap panels which last decades is far cheaper and less maintenance than any solar concentrators or solar tracking that will fail long before the panels. I could see those technologies being useful on a trailer for generating power in remote locations, but not for the typical home or solar farm. I'd imagine those lenses would amplify the shading caused by typical dirt and debris, requiring more labor costs. The other thing is that solar concentrators burn the cells out quicker, it isn't magic free energy. Spending a significant amount more money just to squeeze out more power from the cells doesn't make sense for all applications.
  - dotancohen 4y ago
    > solar concentrators burn the cells out quicker Do you have a source that I could reference for that? Thank you.
    - KleerKut 4y ago
      https://en.wikipedia.org/wiki/Solar_cell#Disposal https://en.wikipedia.org/wiki/Solar_cell#Disposal Concentrators are actively trying to put more of the suns energy (an thus UV degradation) on the cells than can be achieved by simply aiming the cell at the sun. It greatly depends on the type of cell being used, with many technologies having a shorter lifespan than polycrystalline and monocrystalline cells, but they don't last forever out in the sun. A panel boxed up in a warehouse isn't likely to have discernible cell degradation in 10 years. A panel flat on a roof having off-axis light will degrade more, one on a solar tracker will degrade more still, with the benefit of more power per unit time during that shortened lifespan. Add in concentrators and it will degrade more still. Much like anything else. I'm getting no sun indoors, get more standing in my yard, get even more standing near water where it reflects back at me and get sunburn (degradation) quicker in that environment. Obviously it makes sense to aim the panels at the sun, and having a method to seasonally adjust the tilt can be done for very cheap. It can be made to last the life of the panels without repair, and it isn't an outrageous loss of performance if it was forgotten for a few weeks. Active sun trackers can potentially cost more than the panel itself, even more so when factoring in installation and setup. If it fails aiming to one extreme, there will be a substantial loss in power even compared to a panel with a fixed mount. That failure is likely to happen more than a couple times in the life of the panel, unless you replace parts before failure (even more cost), or add concentrators (more cost) to increase output and decrease panel life (more cost yet again). Unless there is a specific reason for all of that cost and complexity, such as space constraints or other factors, then it is cheaper to just lay out more panels. If a new technology comes out where they can stop UV degradation without a large impact on power output, or weight, or cost, then I'll be interested. For my use case I'd rather reduce my energy usage and lay panels in the sun with seasonal cleaning and adjustment.
- jillesvangurp 4y ago
  It's the right mindset. Cheap panels that can be mass manufactured and installed in places where there is plenty of room to do that are a great way to delivering lots of power cheaply. The economic efficiency of the panels is function of how many square meters they take, how expensive those square meters are, how costly it is to maintain and service the setup, how long they last, and how expensive it is to buy and install them, etc. It's not just about the watt/square meter. Less moving parts means less complexity, less things that can break, and overall lower cost. 10% more power at 2x the cost is a net negative.
  - smolder 4y ago
    There are probably applications where 10% more power at 2x the cost make sense, like on a satellite or a solar powered aircraft, maybe.
    - andrewflnr 4y ago
      How much more mass, though? Mass is likely to be at a premium anywhere you can't just also slap down a few more cheap cells, e.g. where there's not much space.
      - smolder 4y ago
        Good points by you and your sibling poster. Maybe this tech really would have a hard time finding a niche when considering mass along with cost/performance characteristics, given other premium or economic options. Maybe on the roof of an expensive high rise it would make sense? On boats? Hard to say.
    - gumby 4y ago
      Indeed, though there are other places of the design space to look. For example in satellites, triple junction cells (generating power from additional parts of the spectrum) are worth the much higher cost as they weigh the same as standard cells, thus generating more power without increasing launch cost.
  - Retric 4y ago
- buro9 4y ago
  As an idea, if a ship were to be electric with battery + solar as the energy source... the ship would be space constrained and obtaining more power with reduced mechanical complexity may be worth it in such industrial settings. Unsure if this is what they're going for, but my initial question to myself was "Where does this make sense?" for the same reason you've highlighted.
- 35mm 4y ago
  Agreed. People somehow miss this point when discussing space based solar arrays that beam power back to Earth.
  - mayama 4y ago
    Is beaming power through atmosphere even feasible? If it is feasible, why aren't we beaming power at least across sea like Mediterranean for example, where laying cable will be expensive. I always thought space beaming power is just science fiction thing.
    - politician 4y ago
      Straight down from space is more feasible than through the atmosphere over the horizon.
    - bryanlarsen 4y ago
      From what I can tell, space solar power would be competitive in those places where the alternative is to fly in fuel for generators. For example military forward operating bases, isolated Northern communities, et cetera.
    - saltcured 4y ago
      I think the atmospheric attenuation problems for a horizontal path are much worse than vertical, not to mention the horizon which would mean many relay stations along a surface path to bend the beam along the curved surface. However, a bigger problem or question to me is what wavelengths can carry useful amounts of energy and be kept in a narrow beam to have high transmission and conversion efficiency from source to collector. Everything from microwaves up to visible light is going to be quite susceptible to atmospheric moisture. Even microwave and infrared communication links can suffer with rain, clouds, or fog. If you can get down to radio frequencies, I don't know whether a narrow beam is really possible. I've seen some hints at the development of rasers (coherent, stimluated emission like lasers and masers but down into "radio" frequencies). But I am not a physicist and do not really understand how such an emission would behave. Could a useful amount of energy be targeted on a "small" receiving antenna without leaking out to other accidental recipients...? Also, for power levels useful to the utility grid, any beam alignment or scattering errors would mean extremely lethal and destructive energy going off-target. Straight down from space, you might delineate a concentric safety exclusion zone around and above a ground station. If beaming horizontally, wouldn't you have to exclude a large wedge of ground and a huge conical section of airspace both before and after the ground site?
- adrianN 4y ago
  It might be interesting for rooftop solar where space is limited and installation costs make up a large part of the expense.
  - k_sze 4y ago
    It’s likely going to make your roof much heavier though, being made of glass. And that’s usually a bad thing. So unless they find a different lighter material with which they can create the same kind of lens, it probably won’t be suitable for many kinds of roofs.
    - edent 4y ago
      I don't know where you live, or what your roofs are made of. But the 1.6m x 1m panels we have weigh only 20KG. That's much lighter than the tiles they replaced.
- deleted 4y ago
  [deleted]
- benj111 4y ago
  Wouldn't the voids allow active cooling / water heating at the same time? If so that certainly increases the utility in a domestic setting at least.
- mort96 4y ago
  If this reasoning was correct, the same would surely apply to tracking solar panels, no? Yet tracking solar panels are all over the place.
beanjuice 4y ago
As the concept was presented originally in 2015 [1], and based on the fabrication portion, the authors seemingly spent 7 years to get to this point [2]. If in 10 years we are still using multi-junction, rare earth metal based panels, as an optimistic outlook on this work, solar panels could potentially reduce the amount of rare earth/minable materials required and instead use larger areas of solar concentration. [1] https://ur.booksc.me/book/55710391/7ba74d https://ur.booksc.me/book/55710391/7ba74d [2] https://www.nature.com/articles/s41378-022-00377-z#Sec6 https://www.nature.com/articles/s41378-022-00377-z#Sec6
Karliss 4y ago
Isn't large portion of the tracking aspect simple geometry and decrease in cross section are based on sin(angle)? No kind of concentrator can solve this limitation without also increasing dimensions and spacing requirements between panels. Are there any other significant effects causing decresase in solar energy conversion in addition to the losses caused by sin(angle) decrease in cross section area? Something like decrease in light to energy conversion efficiency when light density is bellow certain threshold or increased amount of reflected light based on angle ?
- hgomersall 4y ago
  This was my reading of it. The win is that you get to reduce the amount of PV and replace it with cheap glass. I might have missed something though...
jaybeavers 4y ago
And how do you clean these optics? Do they still provide 110% optical efficiency while dirty? Or damaged/scratched from frequent removal/reinstall for cleaning?
politician 4y ago
I wonder how well an inverted pyramid of these optics would perform in a solar thermal application.

73 points by sohkamyung 4y ago

Cool. Imagine when it can be installed on existing panels. I have a 5.5 kW panel system that gets me around 30kwh daily in summers which is probably the best l can get on a stationary roof east facing. They did not give any specifics as to the improvement in efficiency, is it 10%?

bell-cot 4y ago

I get the feeling that generating (say) 10% more power by adding these fancy bits of optics to a set of solar cells would cost far more than (getting the same improvement by) installing 10% more optics-free solar cells.

simonebrunozzi 4y ago
Always been the main problem with concentrated solar.
h0l0cube 4y ago
> 10% more power by adding these fancy bits of optics to a set of solar cells would cost far more than (getting the same improvement by) installing 10% more optics-free solar cells Surely if you're comparing against fixed solar panels, then it would be more than 10%? For tracked solar panels, costlier installation and maintenance would be traded off with efficiency of the prismatic optics and degradation of materials. Economies of scale might favor the optics if it's cheap enough to manufacture (less components, cheap materials etc.)
- bell-cot 4y ago
  If the new optics give X% more power, they compete against "just buy X% more solar panels". (My original "(say)", in front of the "10%", was meant to indicate that the number was arbitrary.) > Economies of scale might favor the optics if it's cheap enough... - Quite true. But note that the article describes the inventor of the new optical system as "assistant professor in astronautics and spacecraft engineering". That certainly suggests cost-insensitive, performance-critical applications - such as cubesats.
  - h0l0cube 4y ago
    You're probably right. Given they seem to be using glass, I'd say it's both too heavy for space (?), and too costly for earth. I guess I'm hoping they take this technique to cheaper easier materials so I can slap this on top of a van and get decent power in a variety of different conditions.
KleerKut 4y ago
Agreed. Unless you have serious space constraints, more cheap panels which last decades is far cheaper and less maintenance than any solar concentrators or solar tracking that will fail long before the panels. I could see those technologies being useful on a trailer for generating power in remote locations, but not for the typical home or solar farm. I'd imagine those lenses would amplify the shading caused by typical dirt and debris, requiring more labor costs. The other thing is that solar concentrators burn the cells out quicker, it isn't magic free energy. Spending a significant amount more money just to squeeze out more power from the cells doesn't make sense for all applications.
- dotancohen 4y ago
  > solar concentrators burn the cells out quicker Do you have a source that I could reference for that? Thank you.
  - KleerKut 4y ago
    https://en.wikipedia.org/wiki/Solar_cell#Disposal https://en.wikipedia.org/wiki/Solar_cell#Disposal Concentrators are actively trying to put more of the suns energy (an thus UV degradation) on the cells than can be achieved by simply aiming the cell at the sun. It greatly depends on the type of cell being used, with many technologies having a shorter lifespan than polycrystalline and monocrystalline cells, but they don't last forever out in the sun. A panel boxed up in a warehouse isn't likely to have discernible cell degradation in 10 years. A panel flat on a roof having off-axis light will degrade more, one on a solar tracker will degrade more still, with the benefit of more power per unit time during that shortened lifespan. Add in concentrators and it will degrade more still. Much like anything else. I'm getting no sun indoors, get more standing in my yard, get even more standing near water where it reflects back at me and get sunburn (degradation) quicker in that environment. Obviously it makes sense to aim the panels at the sun, and having a method to seasonally adjust the tilt can be done for very cheap. It can be made to last the life of the panels without repair, and it isn't an outrageous loss of performance if it was forgotten for a few weeks. Active sun trackers can potentially cost more than the panel itself, even more so when factoring in installation and setup. If it fails aiming to one extreme, there will be a substantial loss in power even compared to a panel with a fixed mount. That failure is likely to happen more than a couple times in the life of the panel, unless you replace parts before failure (even more cost), or add concentrators (more cost) to increase output and decrease panel life (more cost yet again). Unless there is a specific reason for all of that cost and complexity, such as space constraints or other factors, then it is cheaper to just lay out more panels. If a new technology comes out where they can stop UV degradation without a large impact on power output, or weight, or cost, then I'll be interested. For my use case I'd rather reduce my energy usage and lay panels in the sun with seasonal cleaning and adjustment.
jillesvangurp 4y ago
It's the right mindset. Cheap panels that can be mass manufactured and installed in places where there is plenty of room to do that are a great way to delivering lots of power cheaply. The economic efficiency of the panels is function of how many square meters they take, how expensive those square meters are, how costly it is to maintain and service the setup, how long they last, and how expensive it is to buy and install them, etc. It's not just about the watt/square meter. Less moving parts means less complexity, less things that can break, and overall lower cost. 10% more power at 2x the cost is a net negative.
- smolder 4y ago
  There are probably applications where 10% more power at 2x the cost make sense, like on a satellite or a solar powered aircraft, maybe.
  - andrewflnr 4y ago
    How much more mass, though? Mass is likely to be at a premium anywhere you can't just also slap down a few more cheap cells, e.g. where there's not much space.
    - smolder 4y ago
      Good points by you and your sibling poster. Maybe this tech really would have a hard time finding a niche when considering mass along with cost/performance characteristics, given other premium or economic options. Maybe on the roof of an expensive high rise it would make sense? On boats? Hard to say.
  - gumby 4y ago
    Indeed, though there are other places of the design space to look. For example in satellites, triple junction cells (generating power from additional parts of the spectrum) are worth the much higher cost as they weigh the same as standard cells, thus generating more power without increasing launch cost.
- Retric 4y ago
buro9 4y ago
As an idea, if a ship were to be electric with battery + solar as the energy source... the ship would be space constrained and obtaining more power with reduced mechanical complexity may be worth it in such industrial settings. Unsure if this is what they're going for, but my initial question to myself was "Where does this make sense?" for the same reason you've highlighted.
35mm 4y ago
Agreed. People somehow miss this point when discussing space based solar arrays that beam power back to Earth.
- mayama 4y ago
  Is beaming power through atmosphere even feasible? If it is feasible, why aren't we beaming power at least across sea like Mediterranean for example, where laying cable will be expensive. I always thought space beaming power is just science fiction thing.
  - politician 4y ago
    Straight down from space is more feasible than through the atmosphere over the horizon.
  - bryanlarsen 4y ago
    From what I can tell, space solar power would be competitive in those places where the alternative is to fly in fuel for generators. For example military forward operating bases, isolated Northern communities, et cetera.
  - saltcured 4y ago
    I think the atmospheric attenuation problems for a horizontal path are much worse than vertical, not to mention the horizon which would mean many relay stations along a surface path to bend the beam along the curved surface. However, a bigger problem or question to me is what wavelengths can carry useful amounts of energy and be kept in a narrow beam to have high transmission and conversion efficiency from source to collector. Everything from microwaves up to visible light is going to be quite susceptible to atmospheric moisture. Even microwave and infrared communication links can suffer with rain, clouds, or fog. If you can get down to radio frequencies, I don't know whether a narrow beam is really possible. I've seen some hints at the development of rasers (coherent, stimluated emission like lasers and masers but down into "radio" frequencies). But I am not a physicist and do not really understand how such an emission would behave. Could a useful amount of energy be targeted on a "small" receiving antenna without leaking out to other accidental recipients...? Also, for power levels useful to the utility grid, any beam alignment or scattering errors would mean extremely lethal and destructive energy going off-target. Straight down from space, you might delineate a concentric safety exclusion zone around and above a ground station. If beaming horizontally, wouldn't you have to exclude a large wedge of ground and a huge conical section of airspace both before and after the ground site?
adrianN 4y ago
It might be interesting for rooftop solar where space is limited and installation costs make up a large part of the expense.
- k_sze 4y ago
  It’s likely going to make your roof much heavier though, being made of glass. And that’s usually a bad thing. So unless they find a different lighter material with which they can create the same kind of lens, it probably won’t be suitable for many kinds of roofs.
  - edent 4y ago
    I don't know where you live, or what your roofs are made of. But the 1.6m x 1m panels we have weigh only 20KG. That's much lighter than the tiles they replaced.
deleted 4y ago
[deleted]
benj111 4y ago
Wouldn't the voids allow active cooling / water heating at the same time? If so that certainly increases the utility in a domestic setting at least.
mort96 4y ago
If this reasoning was correct, the same would surely apply to tracking solar panels, no? Yet tracking solar panels are all over the place.

beanjuice 4y ago

As the concept was presented originally in 2015 [1], and based on the fabrication portion, the authors seemingly spent 7 years to get to this point [2]. If in 10 years we are still using multi-junction, rare earth metal based panels, as an optimistic outlook on this work, solar panels could potentially reduce the amount of rare earth/minable materials required and instead use larger areas of solar concentration. [1] https://ur.booksc.me/book/55710391/7ba74d https://ur.booksc.me/book/55710391/7ba74d [2] https://www.nature.com/articles/s41378-022-00377-z#Sec6 https://www.nature.com/articles/s41378-022-00377-z#Sec6

Karliss 4y ago

Isn't large portion of the tracking aspect simple geometry and decrease in cross section are based on sin(angle)? No kind of concentrator can solve this limitation without also increasing dimensions and spacing requirements between panels. Are there any other significant effects causing decresase in solar energy conversion in addition to the losses caused by sin(angle) decrease in cross section area? Something like decrease in light to energy conversion efficiency when light density is bellow certain threshold or increased amount of reflected light based on angle ?

hgomersall 4y ago
This was my reading of it. The win is that you get to reduce the amount of PV and replace it with cheap glass. I might have missed something though...

jaybeavers 4y ago

And how do you clean these optics? Do they still provide 110% optical efficiency while dirty? Or damaged/scratched from frequent removal/reinstall for cleaning?

politician 4y ago

I wonder how well an inverted pyramid of these optics would perform in a solar thermal application.