Semi-Transparent Solar Cells Could Make Greenhouses Self-Sufficient (newatlas.com) 73
An anonymous reader quotes a report from New Atlas: Organic solar cells (OSCs) have a few advantages over other designs. They still collect energy from sunlight, but can be made more flexible, transparent (or at least semi-transparent) and can be tuned to only absorb certain wavelengths of light. That potentially makes them perfect for greenhouse roofing -- they can let most light through for the plants, while harvesting enough to offset a decent chunk of the facility's energy needs. "Plants only use some wavelengths of light for photosynthesis, and the idea is to create greenhouses that make energy from that unused light while allowing most of the photosynthetic band of light to pass through," says Brendan O'Connor, corresponding author of the study [from North Carolina State University]. "However, until now it wasn't clear how much energy a greenhouse could capture if it was using these semitransparent, wavelength selective, organic solar cells."
To begin to answer that question, the researchers modeled how much energy would be coming in from a greenhouse with OSCs in the roof, versus the amount of energy it would normally consume. The idea was to find the point where the greenhouse becomes energy neutral -- that is, it generates enough energy from the Sun to completely power itself. For this study, the theoretical greenhouses were modeled on the energy needed to grow tomatoes in three locations with different climates -- Arizona, North Carolina and Wisconsin. As a bonus, the OSCs are effective insulators too, helping maintain the right temperature. The team found that there would be a small hit to the amount of usable light the plants inside would receive, but the benefits would be worth it. In the famously sunny Arizona, for example, a greenhouse with OSCs installed could become energy neutral while blocking just 10 percent of the light the plants need. This shouldn't negatively affect the plants, the team says. In fact, the energy output could be doubled with just a little more light blocked. In North Carolina, sunlight is a little more sparse, so a greenhouse would need to block 20 percent of the photosynthetic light to become energy neutral. Chilly Wisconsin winters would be too much to ever achieve neutrality though, but these greenhouses could still generate almost half of their energy needs. The new study was published in the journal Joule.
To begin to answer that question, the researchers modeled how much energy would be coming in from a greenhouse with OSCs in the roof, versus the amount of energy it would normally consume. The idea was to find the point where the greenhouse becomes energy neutral -- that is, it generates enough energy from the Sun to completely power itself. For this study, the theoretical greenhouses were modeled on the energy needed to grow tomatoes in three locations with different climates -- Arizona, North Carolina and Wisconsin. As a bonus, the OSCs are effective insulators too, helping maintain the right temperature. The team found that there would be a small hit to the amount of usable light the plants inside would receive, but the benefits would be worth it. In the famously sunny Arizona, for example, a greenhouse with OSCs installed could become energy neutral while blocking just 10 percent of the light the plants need. This shouldn't negatively affect the plants, the team says. In fact, the energy output could be doubled with just a little more light blocked. In North Carolina, sunlight is a little more sparse, so a greenhouse would need to block 20 percent of the photosynthetic light to become energy neutral. Chilly Wisconsin winters would be too much to ever achieve neutrality though, but these greenhouses could still generate almost half of their energy needs. The new study was published in the journal Joule.
Semi-transparent aluminum (Score:2)
Re:Semi-transparent aluminum (Score:4, Funny)
Optimist.
The aluminum is semi-opaque.
disadvantage (Score:3)
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They are also a solution in search of a problem.
There is no shortage of space to put solar panels. There are 20 billion square meters of roofs in America. There are millions of acres of parking lots, and 60 million acres of desert.
There is no reason to use the same space for a complicated and expensive solar panel array + greenhouse. Just build a greenhouse and put the solar array somewhere else.
This is almost as dumb as Solar Freakin' Roadways [youtube.com].
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Solar Freakin' Roadways are freakin' brittle and break down much faster than the classic materials used for roadways. Good idea on paper, but implementing it is not great yet.
Source, sorry French article:
https://www.nextinpact.com/new... [nextinpact.com]
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Good idea on paper, but implementing it is not great yet.
Solar Roadways seem like a good idea for about 5 seconds until your brain turns on. Cost-effective solar panels are hard enough without designing them to handle semis and snowplows driving over them.
The solar roadway tiles cost 5 times as much as normal solar panels and last a tenth as long. This makes them fifty times more expensive.
And, like the dual-purpose greenhouse-solar-panels, they are trying to solve a non-existent problem. We don't lack space to put solar arrays.
Re: disadvantage (Score:2)
We don't even lack space to put solar cells along our roads.
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Put them *over* the road. You accomplish everything the solar freaking roadways are supposed to:
1) generate power
2) you don't have to clear snow off the road
Much more practical for parking lots though, since you would also get these benefits:
3) no long distance low-voltage DC transmission losses
4) also keeps your car cool in the summer sun
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I somehow feel like all highway driving being effectively a tunnel would have some spillover costs.
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You wouldn't make it a box. Just a roof with open sides. You can still admire the countryside as you drive, but you don't have to worry about snow, rain or glare.
Agreed, it's more practical for parking lots though.
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I was more concerned about the light.
It seems you'd have perpetual dusk like conditions in the shadow, but maybe I'm grossly underestimating the amount of light penetration from the side.
Daytime driving is safer, it seems making all driving non daytime would lead to more accidents.
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I think you'd get a lot of light from the sides, and you could put transparent panels at intervals in the roof too, if it wasn't enough. It would probably be brighter than any downtown New York street without the sun directly overhead.
Re:disadvantage (Score:4, Interesting)
They are also a solution in search of a problem.
They are not. Just because there is space in general, it doesn't mean that this space is available to you for an affordable price. If you have to build a greenhouse, you have to use real estate, which either you have to buy first, or you have to clear of other uses. If you can make double use of that space by roofing your greenhouse with solar panels, that's nice.
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If they can get the durability up to a few years, then most greenhouse roofing doesn't last that long anyway. I bet they chose this use case specifically because durability isn't as big of an issue as it would be for, say, residential glass installations.
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Greenhouses are usually made from glass. Unless you use plastic foil, eek! ... except one throws a stone a bird or hail hits it.
Glass greenhouses last forever
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...Do you run into many bird-throwers where you are? :)
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No, and hail too is extremely rare :D
Passive Solar Greenhouse (Score:3)
OR we could use the advanced technologies of a brick wall and an insulating blanket to become energy neutral.
https://www.lowtechmagazine.co... [lowtechmagazine.com]
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True, a brick wall is just about the most unsexy thing ever.
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True, a brick wall is just about the most unsexy thing ever.
Unless you have a mortar fetish.
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She's built like a brick shit house used to be high praise.
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True, a brick wall is just about the most unsexy thing ever.
Not according to The Commodores.
"She's a brick...wall" do do doo do
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OR we could use the advanced technologies of a brick wall and an insulating blanket to become energy neutral.
No need for either/or! Appropriate use of both high and low technology is quite cool. Let the brick be the thermal mass to regulate temperature, and then a small and affordable string of solar panels can drive, say, water pumps for aquaponics.
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There are some key areas where some extra electrical energy would be useful for a passive solar greenhouse, like removing water vapor from the air. So yeah, the two technologies could complement each other very nicely.
That said, it'd have to be real cheap to be worthwhile. We'll see how cheap they can get it.
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That's a pretty good idea, and reasonably low tech as well.
One issue though is that this style of greenhouse already struggles with an overly high water vapor percentage. The plants naturally perspire water, so as long as you're trapping the warm air inside the greenhouse the percentage of water vapor in the air will slowly increase.
During the summer this is no big deal, because during days with high solar energy you can make use of the excessive energy by venting the wet air and and replacing it with warm,
OT - greenhouses (Score:1)
Why use specialized panels? (Score:2)
Why not just set up a normal panel next to the greenhouse to run fans and watering equipment and let the plants get 100% of the light instead of using exotic (read: expensive) panels that also reduce the amount of light getting to the plants? This seems like a solution in search of a problem that doesn't exist.
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That is not a greenhouse, that is a vegetable factory ...
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reduced effort to install 1 roof with solar panels than 1 roof plus 1 setup of solar panels,
uses less space,
may receive VC funding, and get bought out by one of the big guys, earning the creators some big bucks.
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Presumably they want to use 100% of the available space for greenhouses, rather than 50% for greenhouses and 50% for solar panels. And mostly in places where there's lots of sunlight so losing 10-20% of it is either irrelevant or beneficial.
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Well, it takes up more space, adds complexity, and now you've gotta ship two panels instead of one. Plus, you've gotta mount those panels, which requires more expense for material, engineering, etc.
Right now the tech isn't really there to justify these, but I think it's a good thing that they're pursuing it.
In addition to people lowering their carbon-footprints, lowering our land-use footprint is a good thing to pursue too.
As far as supplemental lighting goes -- sometimes you need it, depending on what you
Greenhouses need energy? (Score:4, Insightful)
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What energy needs does a greenhouse have, other than possibly pumping water? Opening/closing vent windows to provide some temperature control?
Those are some good examples. Aquaponics is a great way to grow plants and fish together for a lot of food output, but if the power goes out, the fish can die rather quickly and then the nutrient cycle is in trouble. A charged battery bank really helps the long-term reliability there.
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You can get heat with a black surface. You don't need a semiconductor, organic or not.
And storing heat with a simple thermal mass-- most preferably a phase-change thermal mass, but a simple barrel of water will work-- is simpler and cheaper and more effective than batterieS.
Heat is the lowest form of energy: waste heat is what you get when you've used all of the useable energy.
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You can get heat with a black surface -- that's being heated by the sun.
Unfortunately, in many places, the colder months also don't get much sun, if only due to heavy clouds.
So, yeah, having thermal collectors and thermal mass is great -- but it can only go so far if it's, say, February and you last actually saw enough sun to cast a shadow last week.
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You can get heat with a black surface -- that's being heated by the sun. Unfortunately, in many places, the colder months also don't get much sun, if only due to heavy clouds.
If you don't have sun, the photovoltaics (semitransparent or not) won't do much good either.
So, to summarize: when there is sun available, a black surface is cheaper and more effective to heat the greenhouse than a photovoltaic cell. When there's not sun available, a black surface is cheaper and more effective to not heat the greenhouse than a photovoltaic cell.
So, yeah, having thermal collectors and thermal mass is great -- but it can only go so far if it's, say, February and you last actually saw enough sun to cast a shadow last week.
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What energy needs does a greenhouse have, other than possibly pumping water?
Here in the Netherlands, greenhouses commonly use supplemental lighting during the winter months, on the order of 100 W/m2 for several hours per day. Oh wait...
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I guess you don't know commercial farming very well.
Here's some pub trivia that can help build that view for you:
- the world's biggest vegetable farmers per capita are the Dutch (country of 17 million are only narrowly in second place in total gaming behind the USA).
- the Netherlands has some of the highest energy requirements and largest CO2 emissions in Europe despite lack of heavy industry.
- Rotterdam is the most light polluted place in the world thanks to surrounding greenhouses.
That should hopefully bu
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I didn't realize that Arizona, North Carolina, and Wisconsin were locations in the Netherlands. Your geographic knowledge is remarkable.
Who is talking about those three places. I gave you pub trivia knowledge as examples of energy consumption for green housing. Your puny mind thinking that green houses only apply to three states and those states being unique in the world is your problem not that of anyone else's.
Your geographic knowledge is remarkable.
Oh right if I realised I am replying to dickhead extraordinaire msauve I may have saved myself the effort of typing a reply. Go fuck yourself with a shard from a broken glasshouse. .
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" I gave you pub trivia knowledge"
You'd help yourself if you spent more time studying for your GED/GCSEs, rather than "studying" at the pub, which isn't helping your shortage of brain cells any.
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Lighting, if you're trying to grow plants that need a long day during the winter when it's got a short day outside, or if you're trying to maximize growth during periods where the sun doesn't do a great job at shining, depending on your local climate patterns.
Heating, if you're growing in a particularly chilly area, particularly if you've got periods where you don't really see the sun for a week, and thus don't get any solar heating.
Ventilation for controlling humidity and air movement and temperature.
Contr
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Using solar panels to collect electricity for heating is possibly the least efficient solution to the need. Even ignoring the efficiency, if "you don't really see the sun for a week", how are those solar panels going to collect energy? It simply doesn't make sense. Solar heating is much more efficiently done with physical (e.g. pu
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"Heating, if you're growing in a particularly chilly area, particularly if you've got periods where you don't really see the sun for a week, and thus don't get any solar heating."
Using solar panels to collect electricity for heating is possibly the least efficient solution to the need. Even ignoring the efficiency, if "you don't really see the sun for a week", how are those solar panels going to collect energy? It simply doesn't make sense. Solar heating is much more efficiently done with physical (e.g. pumped liquid, heat storage solutions) than with electrical ones.
Well, yes, but they also make these things called batteries. I presume that for the most part these greenhouses would be designed to produce more power than they needed. I also realize that solar-electric heating is dreadfully inefficient, but a small amount of it can go a long way, particularly if you just need to keep above a danger point for a few hours in the middle of the night. It could make the difference between being able to sleep through the night and having to get up at oh-dark-thirty to start
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You presume wrong. Next?
3D solar panels? (Score:1)
multi-junction solar cell [Re:3D solar panels?] (Score:2)
How would it work to stack these into 3D arrays for higher efficiency? Maybe with a more traditional opaque cell on the bottom?
Is this intended as ironic understatement, or have you independently re-invented the modern multi-junction solar cell [energysage.com]?
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Not sure if it is practical (Score:1)
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Vertical farming is great for salad greens in cities. It's kind of pointless for pretty much anything else, though. Leafy greens don't travel as well as other crops and they grow quickly, so they're an ideal case. Maybe it makes sense for tomatoes too, they usually have to be picked very unripe so they can be shipped.
Oh god this is just wrong... (Score:3, Interesting)
"Plants only use some wavelengths of light for photosynthesis, and the idea is to create greenhouses that make energy from that unused light while allowing most of the photosynthetic band of light to pass through"
No, they utilize the entire visible spectrum and some of the invisible spectrum in both IR and UV, they just utilize some wavelengths more efficiently, while other wavelengths drive other processes more efficiently, depending upon the plant. An example, amber/orange light drives better vitamin production in some types of fodder grasses during the first weeks of growth.
For general vegetative growth and flowering, plants utilize blue and red more efficiently. If you tuned a greenhouse to absorb green light while letting red and blue through, and convert the green light over into more red and blue light, you could run highly-productive greenhouses for typical human crops and herbs.
Alternatively, you could use that energy for atmospheric control, and have a semi self-sustaining greenhouse that only needs water and fertilizer inputs and controls.
Go green! (Score:2)
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Exactly. Sometimes the delta between a hot house tomato and a proper vine ripened tomato is so stark you can see, smell and taste the difference. You can hide some of it by using some kind of varietal, but it's just not the same.
The guy who posted about the Chinese brick wall greenhouse has the right idea, if you want to grow year round. When the weather's right, you can roll up the plastic and get full sun and then convert to greenhouse when the weather gets cold.
I finally succeeded at the hothouse this year (Score:2)
I built a 16'x16' (roughly five meters square) hothouse frame years ago, and put up 6 mil plastic over it.
I *finally* succeeded in keeping my tomatoes through the winter this year.
So as soon as I take down the plastic (once I'm sure we're past the last sub 40F night), the bees can start pollenating!
So I get vine ripened hothouse tomatoes.
Oh, the differences this years that finally led to success:
1) I tacked to the inside instead of the outside of the frame. Also much easier given the height of the roof. We
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LOL, I understand the Quest for Good Out of Season Tomatoes.
That said -- set up a simple computerized controller system for your greenhouse, and remove most of the pain points. Particularly with heating. (Most heater thermostats just plain up suck.) You can set one up pretty easily to monitor temperature, humidity, etc, and feed alerts and alarms to you via twitter or your service of choice.
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Actually, I've done that. It wasn't ready until a couple of days after I needed it last year.
An Arduino with sensors and relays, talking by BLE to a pi 0W . . . it even logs throughout the night.
There's another one to run my lawn sprinklers and irrigation system; I have to refinish it in the next week or so to seed from scratch (the expensive orbit unit failed on *most* circuits, but was still running one, which we noticed being on and didn't worry. By the time we caught on, we'd lost both lawns, at leas
Plants [Re:Oh god this is just wrong...] (Score:2)
"Plants only use some wavelengths of light for photosynthesis, and the idea is to create greenhouses that make energy from that unused light while allowing most of the photosynthetic band of light to pass through"
No, they utilize the entire visible spectrum and some of the invisible spectrum in both IR and UV, ...
No, they don't. Due to the laws of quantum light absorption, chlorophyll can't use light of wavelength longer than a cut-off, set by the energy needed to promote an electron to a higher state in the molecule. For chlorophyll, turns out that's about 0.7 microns-- the far edge of the red. Anything with wavelength longer than that is not used.
Take a photo of plants using infrared-sensitive film, and you'll see that they are reflective as heck. They don't absorb in the infrared. But there's still plenty of
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There's more than just chlorophyll structures in plants that react to wavelengths of invisible radiation, moron. But just FYI, there is a chlorophyll type f which is purely IR responsive and exists in plants. Perhaps you should actually be someone that has worked in the industry for well over a decade as a researcher before trying to correct someone.
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There's more than just chlorophyll structures in plants that react to wavelengths of invisible radiation, moron. But just FYI, there is a chlorophyll type f which is purely IR responsive and exists in plants.
Fair enough: there are some cyanobacteria which had a different chlorophyll variant, chlorophyll f [sciencemag.org], which absorbs out to 750 nanometers... a whole seven percent longer wavelength than the 700 nm cutoff I stated in my comment. But I don't think any greenhouses are growing cyanobacteria.
And that still leaves the 50% of the solar intensity that is at wavelengths longer than 750 mn.
Perhaps you should actually be someone that has worked in the industry for well over a decade as a researcher before trying to correct someone.
ROFL. But perhaps you should talk to somebody who has actually taking photographs of plants in near-infrared light.
Plants are r [cooldigital.photography]
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Interestingly, IIRC -- this is going back a while as far as my college courses go -- chlorophyll can only use one frequency of light. (I -think- UV, but I might be wrong.) It's all the other pigments - xanthophylls and such -- that capture the rest of the spectrum that the plant can use, and shuttle the energy to the chlorophyll molecule for use.
Nobody cares (Score:2)
"The team found that there would be a small hit to the amount of usable light the plants inside would receive, but the benefits would be worth it."
Nobody cares, that's why the LEDs are for. What else would you need the solar roof?
People are doing like that it in vertical gardening right now _without_ a transparent roof.