Monday, June 23, 2014

Photovoltaic Water


Water produced by condensing humidity from the air using solar energy. Starring Francesco El Asmar. Photo by Ugo Bardi



When we started working on producing water from atmospheric humidity, myself and my friend and colleague Toufic El Asmar thought it was a mad idea. Energy is expensive and water condensation requires a lot of it. Yet, as we kept working on the concept, we found that it made sense. Sure, it takes energy, but, with the progress of technology, renewable energy is becoming cheaper and cheaper. And at some moments, renewable energy really costs zero. At those moments, you should store it, but storage is the expensive part of renewable power. So, why not transform solar energy into something that you can store at little or no cost, for instance clean, drinkable water? After all, water is fast becoming a scarce commodity in many regions of the world.

So, the idea was born of a "solar water machine" which uses electric energy from photovoltaic panels to drive a water condenser which collects humidity from the air. The water is then filtered and made drinkable by adding a small amount of natural salts. The machine is more complex than this; it also collects rainfall and it can clean and purify water from almost any source, producing up to two hundred liters of pure water per day. Its solar panels make it completely self-sufficient: you may place it anywhere; it doesn't need to be connected to the grid (although it may be). So, it is good for remote places, for emergency situations, and for a variety of needs. Here is the "Acqua dal Sole" system, the day of its official presentation in Capannori, Italy. The people involved in the project are lined up in front of the machine (including yours truly).



Now that I told you the essential, let me tell you some more details about this idea. It all started some years ago, when myself and Toufic El Asmar prepared a project about using solar collectors to produce air conditioning for North African and Mid-Eastern Countries. The idea was that these countries enjoy a high solar insulation, which could be collected using parabolic mirrors to heat up an absorption air conditioning system. The project was approved by the European Commission with the name of "REACT" and it led to the manufacturing of two prototypes, one in Morocco, the other in Jordan.

As time went by, however, the rapid fall of the price of photovoltaic panels made parabolic solar collectors obsolete. But while working on the React project, we noticed how solar refrigeration could produce a lot of water by condensation from the air. That led us to study the subject more in detail and the European Commission sponsored a project called "Aqua Solis". Our idea was to study an approach completely different than the large scale desalination plants which are commonly used nowadays to produce water for dry countries. The idea was to develop "village scale" systems; improved versions of the old "solar still" idea. Cheap, simple, and with no need of the expensive pipeline systems needed for the conventional desalination plants. The basic idea was to create versatile systems which could use photovoltaic energy for water production, but also for any use needed at a particular moment

In time, this study evolved into a patent filed by me (Ugo Bardi) and Toufic El Asmar and to a working device: the "Acqua dal Sole" system, built by the Italian companies Sinapsi and Sinerlab, on a project by Archistudio. The "Acqua dal Sole" system is at present located in an area close to the airport of Capannori (near Lucca, in Italy) where a high tech aeronautics company, "Zefiro" has kindly offered space for a test. The water produced is free for anyone stopping by, although for bureaucratic reasons you will read on the tap the sign "not drinkable" (in Italian). But it is perfectly drinkable and very good, I can tell you that!

We are looking at practical applications and markets for this device. Of course, that depends on the cost but, as the prices of PV keep falling, it is likely that water from the air could be a revolution in the way water is produced in the world, especially in areas where it is badly needed. And also on the way renewable energy is stored.

Once you have seen the "photovoltaic camel" you can understand how fast the range of applications of PV panels is growing. Photovoltaics is an emergent technology which has the possibility of reshaping the world in ways which, at present, we can't even imagine.





Acknowledgement: the people who worked on the "Acqua dal Sole" project

Ugo Bardi (University of Florence)
Eugenio Baronti (Zefiro s.r.l.)
Lorenzo Cardarella (Sinapsi s.r.l.)
Toufic El Asmar (Food and Agriculture Organization, FAO)
Filippo Niccolai (Sinerlab s.r.l.)
Francesco Niccolai (Sinerlab s.r.l.)
Michele Tosti (Sinapsi s.r.l.)





28 comments:

  1. Ugo, does this not just steepen the Seneca Cliff?

    To me, lack of water is a very clear signal that fewer humans should be living there. Instead, we are using depleting fuels to mine, refine and manufacture depleting resources to allow growth in areas that do not have the carrying capacity for so many people. Why is this a good idea?

    I have also often wondered what the consequences to natural systems will be, as we mine the aquifers, divert the rivers, and even strip the fog out of the air. I wouldn't be surprised if this does not end well.

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    1. But I think, Ruben, that your question deserves a more elaborate answer than the one I gave about water from air being renewable. The question is deeper and more subtle than that. What causes the Seneca cliff is not so much using up non renewable resources. It is the desperate attempt to cling to the old ways, to stick to the known, to avoid all change, to keep the new away. The cliff is the way that the universe uses to tell us that this is not possible. And in so doing the universe teaches us a harsh lesson. And we never learn anyway.

      Water from air is not an attempt to stick to the old ways, it is part of the phenomenon we call "emergence" - it is when several usuals stick together to form the unusual. It is what we call paradigm shift. Water from air, in itself, is nothing special. It is just a combination of known technologies, but in my opinion it signals the emergence of something very unusual; a new planetary metabolism; something which has the power to change the world in ways we can't even imagine.

      It will end well - but that depends on what we mean for "well". :-)


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  2. The Seneca cliff? I think not. The cliff is the result of of using up non-renewable resources. Water from air is renewable.

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    1. BTW, stripping the fog from air is reversible in a very short time. Fog you were born and fog you will return. There is no way of running out of fog, even though humans are clever enough that they could even manage that.

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  3. Ugo
    I do not understand the paradigm shift.
    Affordable PV at the moment derives from the existing industrial trading complex.
    (As BTW do most of the clothes and shoes worn even in out of the way places by poor people whose consumption of primary industrial fuel is close to zero. These people could revert probably to local renewable primary sources of clothes in many cases if they could not afford the cast-offs of mass production, but PV has no 'local equivalent' unless small-scale wind-powered generation and 'cast-off' electrical generators could be considered 'local'.)

    PV can make energetic sense (with strong caveat as to the limited rate of increased growth - see Michael Dale - Stanford - presentations GES Edinburgh 2013) within, roughly, the estimated legacy industrial period that we can look forward to. But beyond that period?

    With regard to 'clean water' provision, yes, this could be a very high value result and justify community priority investment. But I can see no way PV-water could provide for agriculture if irrigation is the local limiting factor. The scale of energy harvesting is much too limited unless you can provide quantified estimates for installed PV areas commensurate with field irrigation. And, following my drift on dependent innovation, even the more efficient trickle-irrigation requires existing large scale industry to back it up.

    There is an argument (see salt-water greenhouses) where microcosm greening of arid areas - and water retention - could eventually create macro-changes on a regional scale in self-renewing water from air. Such’amplification’ could be a virtuous spiral that might free ecosystems and consequently human food from existing dependency on ever larger industrial inputs. Perhaps.

    Can PV escape from its dependence on the industrial background system and the inherent future decline in the rate of the vast fossil energy that fuels the present industrial system?
    best
    Phil

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    1. Dear Phil, there is this legend that PV is simply an extender of the lifespan of fossil fuels. I don't know where it comes from (perhaps from an old article by George Odum?), but it is surely stubborn. But even using a rather primitive method of evaluation such as EROEI, it is clear that PV is a metabolic system on a par with the well known biological ones based on photosynthesis. Even the most pessimistic (and most likely wrong) evaluations of the EROEI of PV give to it a value around 3; which is sufficient for replacing plants after their obsolescence and obtaining an energy surplus. In reality, the EROEI of PV is much higher and improving with the progress of the technology.

      So, PV can survive and prosper provided it is embedded in a world of sufficient complexity. In other words, a world which can maintain a large scale industrial capability. Of course, if we go back to small agricultural villages, this capability will be lost. King Arthur didn't have PV panels on the roofs of the castle of Camelot, of course. Some of us seem to have decided that this is the only possible outcome of our present predicament; but in my opinion that's not true. We can maintain a complex civilization provided that we have a sufficient energy flux to feed its complexity. PV can provide this flux, supposing that the decline of fossil fuels is not so rapid and destructive as it is seen in some scenarios.

      Give to the world's industrial system a few more decades to go without major disasters, and PV will grow and become the backbone of a new metabolic system which may survive for a long, long time without any imput from fossil fuels.

      That doesn't mean that PV can solve the problems humans have created for themselves by excessive growth and impact on the ecosystem; that's another matter. For instance, by all economic metrics available, photovoltaic water is too expensive for agriculture. Nevertheless, you can think of "PV greenhouses" - as you mention - which recycle at 100% the internal humidity by means of water absorbers and which could subsist in very dry environments without the need of irrigation. It is also an idea which we explored with Toufic El Asmar, although we couldn't do practical tests.

      Again, this is not a trick to feed a humankind unable to stop its growth - nothing can keep feeding something that keeps growing forever. However, the PV greenhouse is an interesting illustration of PV as a metabolic system. It is a sort of super-plant that improves the efficiency of photosynthesis and makes it possible in areas where now plants cannot survive.

      So, as I said in other contexts, PV is a true game changer which may create a world which we have difficulties even to imagine right now.

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    2. Dear Ugo
      Thank you for taking the time - I am sure I am not the only one to find your arguments interesting.

      At the moment, though I continue to equate 'complexity' in our industrial civilisation with, say, 4 billion tons of coal per annum (with other key energy and material inputs) fuelling China's electricity production and thereby enabling very large scale production of a range of goods, including much cheaper PV modules that benefit from such 'economies of scale'. Electricity is very useful energy.

      I have a problem with the diffuse energy of sunlight. Crops need more than a billion hectares of sunlight 'interception' surface. World arable area is ~1.4 billion hectares (Wikipedia). Even if PV energy capture (output as electricity) were x15 the effective 'efficiency' of photosynthesis (output chemical energy), our large-scale complex industrial civilisation would require more than field scale PV sunlight interception to sufficiently replace the existing fossil fuel inputs that the said industrial complexity relies on.

      Arguably I can see that 'intermediate' scale deployment of PV could maintain sufficient 'complexity' to capture sufficient economy of scale to grow the new system to replace the old.

      But I have not had a 'conversion experience' yet! ;)

      I met a couple of times the guy Charlie Paton who set up Seawater Greenhouses. The technology has been made to work, and as he says would benefit from PV to run the fans. Fans do not have an exorbitant demand for electricity, nor indeed do water pumps, so the technologies could be complementary to produce 'intermediate' scale water for greenhouse vegetable growing. Whether microclimate benefits could create macroclimate change for arid areas is another matter altogether!
      http://www.seawatergreenhouse.com/

      Anyway - we perhaps still have time for some synergistic innovation and complementary uses for PV - so good luck to all the colleagues!

      very best
      Phil

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  4. Congratulations to the «Acqua dal sole» crew! And thanks to Dr Bardi for bringing it to the light that illuminates our learning on «Resource Crisis».

    Dr Bardi, you have written about a paradigm becoming obsolete. I suspect all of us are hoisted on our own such paradigmatic petards, from time to time. Myself, I suspect one paradigmatic blind spot is our belief that energy must be available at the press of a button, the flick of a switch, the turn of an ignition key…

    My father used to say that when he was dissatisfied, he would climb a hill on a dark and stormy night, shake his fist at the skies and shout, “Listen here! I want what I want when I want it” Then the clouds would part, the lightning would flash, the thunder would roll, and a mighty voice would come booming down: “Good! 'Cuz you’ll get what you get when you get it.”

    Water can be gathered when available and stored. Ancient civilizations developed ingenious water storage and irrigation systems in an arid environment at the bottom end of the Arabian peninsula. Rain and humidity are not propitious for haymaking: an old saying advises us to “Make hay while the sun shines.” Energy-on-demand facilitates commerce and JUST-IN-TIME manufacturing today. In time past, folks acknowledged that “Wind and tide wait for no man” — once phrased in English as “And te tide and te time þat tu iboren were, schal beon iblescet.” In spite of this, world trade flourished and empires were powered (and overthrown) with wind power and being watchful of the tides.

    We can see well enough to go for a walk, ride a bicycle, barbecue a dinner, etc, by full sunlight and also on a heavily overcast day. Even when the light is low, it still provides us with useful albeit far less abundant energy (approximately an order of magnitude).

    With technology (manipulated knowledge), along with self-discipline, wisdom and humility, we can make do… with what we get when we get it.

    David F Collins

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    1. Great scene, Dave!!! If you don't mind, I'll reuse it - citing you, of course.

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  5. Have you seen the warkawater system?

    http://www.architectureandvision.com/projects/architecture/84-projects/art/492-073-warkawater-2012?showall=&start=1

    RE

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    1. I had seen it. Looks like a big kludge to me.

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    2. They CLAIM some pretty good results with this system. 25 Gallons Potable Water/Day. We are thinking of building one at our next Convocation. Comes in at a good price of around $550 supposedly. How much does your system cost? What is the output?

      RE

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    3. Well, maybe this one is better than others. But things called "solar stills" have been around for decades and never stuck. Too low the output. Western engineers seem to enjoy the idea to teach Africans how to do low tech, but it just doesn't seem to work. It is the same for solar concentrators to prepare food. They are the darling of westerners but, as far as I am told, in Africa noone uses them.

      I think we need something more versatile, which can also purify wellwater and produce electric power. this is the idea, at least. Then, it is all to be seen. It depends on how low the price of PV will go, whether there will develop a market for standalone systems. This means a completely different electronics. Many things.......

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    4. I don't like anything that requires photovoltaics. This is totally dependent on mining of rare earths and a global delivery system. May work short term, long term its a goner. You gotta be able to build out of local materials with basic techniques.

      RE

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    5. RE - just a little step back. Are you sure that PV needs rare earths? Check.....

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    6. "Materials presently used for photovoltaics include monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium gallium selenide/sulfide.12"

      Cadmium, Indium, Gallium, Selenium all fit under rare earths I believe. Haven't looked at a periodic table in a while.

      In any event, this is high tech manufacturing you can't do at home, it needs a global supply chain to function.

      RE

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    7. RE, none of these are rare earths. And most of those you list are not used in practice. All what you need to make a good solar cell of the kind used nowadays is silicon and aluminum; then you need traces of nitrogen, boron and phosphorous, all abundant elements and - presently - a little silver (but it is not fundamental). PV cells are truly forever: they only need materials which will never be in short supply.

      Then, of course you need a supply chain to keep PV systems to work. No PV on the roof of King Arthur's castle

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    8. Well, I am all for PV cells if they can be manufactured without producing a large waste stream in the process, but since most are produced in China and they have a small pollution problem, I am not convinced this manufacturing process is benign.

      Also, while Aluminum is abundant, its production requires a LOT of electricity as I recall. Not to mention all the heavy equipment powered by Diesel Fuel used to mine the ores.

      When you can run heavy equipment on Solar PV cells, this might be a sustainable system. At best, its a bridging mechanism, but it can't be sustained outside the Industrial economy.

      RE

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  6. cheffigata! (dai prof, tanto gli anglosassoni non la capiscono questa ;D)

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  7. Congratulations! What a wonderful idea! What is the cost structure (price per liter, with/without added minerals?). I'm guessing that there are niche applications where this method is already practical.

    A few years back I thought about using windmill/PV electricity to produce nitrogen fertilizer (say, in the form of ammonia but perhaps of nitrates). The thought occurred to me when I learned that around 1900 hydropower electricity in Norway was used industrially to make nitrogen compounds (to be later replaced by the current process that uses natural gas). I think ammonia could be a liquid fuel for transportation, as well as a nitrogen fertilizer. The idea of using renewable electrical power to generate nitrogen compounds occurred earlier to an engineer at the University of Minnesota, who I believe has already implemented the idea partially. Of course the recent (and temporary) low natural gas prices in the US have cast a shadow upon this research.

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    1. Yes, I also had the idea of producing ammonia out of electric power. Today, it could be done by driving fuel cells in reverse. But we could nver get financed for this. Do you have a reference for the Norwegian process?

      About costs, this is a prototype, so I can't really say. We have to test, to see if there is a market, then we can start thinking in terms of cost.

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    2. Here is a website that is probably related to the University of Minnesota project that I dimly remembered:
      http://nh3fuelassociation.org/2013/08/28/ammonia-production-using-wind-energy/

      I've not found the reference to the Norwegian process circa 1900 (I'm in Switzerland for the summer and away from my usual library). It was in a book for the general public about the creators of the H-B process. I'll keep looking. I've since found references to some kind of nitrogen compound generation at the Aswan Dam in Egypt. Will send.

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    3. Here's a link with references to 20th century use of hydropower to produce ammonia:
      http://www.hydroworld.com/articles/hr/print/volume-28/issue-7/articles/renewable-fuels-manufacturing.html

      Here is the relevant paragraph:
      From a technical standpoint, there is no question that ammonia can be produced from water, air, and hydropower. The list of countries that produced ammonia from hydropower in the 20th century is fairly long — Canada, Chile, Egypt, Iceland, India, Norway, Peru, and Zimbabwe.6 Of the about ten plants that were operating then, only three — Que Que in Zimbabwe; Cuzco in Peru; and a facility in Aswan, Egypt — are believed to be still in operation.

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  8. solar energy is one of the renewable sources of energy......nice job... .. Solar Panel

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  9. The idea is wonderful and definitely new.

    However, what type of condenser (or cooling system) empowered by the solar panel did you use to make the water condense ?

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  10. Water pumps have various applications. They can be utilized for private, modern and business use, contingent on the components controlled by them. However, the elements of every one of these pumps continue as before. They all are utilized to transport water and different sorts of liquids starting with one position then onto the next.

    ReplyDelete
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Who

Ugo Bardi is a member of the Club of Rome and the author of "Extracted: how the quest for mineral resources is plundering the Planet" (Chelsea Green 2014)