Faerie’s solar jerrycan

A stunning concept solar charger for Volvo.

The American winners of a design competition for a portable solar charger display pavilion launched by Volvo Italia came up with this, throwing in a solar charger:

Beautiful? Without a shadow of doubt. Practical? At first sight it looks not. But replace the car with a Hummer and the background with a US Army encampment in Afghanistan, and you think, something like this could become the solar jerrycan.

Wehrmacht-Einheitskanister of WWII  Source
Wehrmacht-Einheitskanister of WWII Source

Update: first paragraph amended in response to niggles of commenters rather missing the point IMHO.

Author: James Wimberley

James Wimberley (b. 1946, an Englishman raised in the Channel Islands. three adult children) is a former career international bureaucrat with the Council of Europe in Strasbourg. His main achievements there were the Lisbon Convention on recognition of qualifications and the Kosovo law on school education. He retired in 2006 to a little white house in Andalucia, His first wife Patricia Morris died in 2009 after a long illness. He remarried in 2011. to the former Brazilian TV actress Lu Mendonça. The cat overlords are now three. I suppose I've been invited to join real scholars on the list because my skills, acquired in a decade of technical assistance work in eastern Europe, include being able to ask faux-naïf questions like the exotic Persians and Chinese of eighteenth-century philosophical fiction. So I'm quite comfortable in the role of country-cousin blogger with a European perspective. The other specialised skill I learnt was making toasts with a moral in the course of drunken Caucasian banquets. I'm open to expenses-paid offers to retell Noah the great Armenian and Columbus, the orange, and university reform in Georgia. James Wimberley's occasional publications on the web

37 thoughts on “Faerie’s solar jerrycan”

  1. You’re joking, right? As sculpture, I suppose it works. As a work of engineering, the person who perpetrated it ought to be locked up in an insane asylum. Engineering wise, it’s a bad joke.

    1. First, are you an electrical or structural engineer? Second, have you seen the performance specs on the piece? If not, you have no grounds from which to comment on its precise functionality.

      All that leaves is your rather limited subjective opinion on its aesthetics which, I guarantee, will hold little weight in the design community.

      You may not like this object. But, frankly, no one cares.

      1. Mechanical engineer, tooling. However, unless you sign a non-disclosure agreement, I can’t show you most of my work.

    2. Brett,

      As a repair and alignment technician, I always assumed engineering was a jobs program for the criminally insane. 😉

  2. Bellmore, it’s made of webbing and carbon-fiber tubing, and folds up and fits in the trunk.

    “the carbon fibre tube ring is deformed into shape by the tailoring of skin which binds it. In response, the frame pushes out while the skin pulls in, creating a form-force equilibrium that is lightweight, cost-efficient, and easy to assemble and disassemble. The pavillion is designed so that when it is disassembled it will fit inside the V60’s trunk dimensions for easy transportation.”

    1. It never occurred to me that it was anything but foldable. The screens you buy for sticking inside car windows work on the same principle.
      Brett says he’s an engineer, but his design philosophy is peculiar. Machines should be ugly and clunky? Machismo in the stride of yon connecting rod?

      1. Did you fail to notice what a small fraction of the thing’s surface actually consisted of PV panel? Maybe a third, tops? Probably more like a quarter? Yeah it’s graceful looking as all get out, and horribly inefficient in it’s use of space, too.

        Further, I’ve got a child’s tent that uses the same structural principle. It’s really clever, and mind blowingly difficult to pack away once you open it, and that’s with the advantage that it’s a tad smaller than my reach. You’d need a TEAM to stow this thing!

        Meanwhile, there are PV panels out there that will flex enough that they can be rolled up. A sheet that you unroll and attach to the front and rear bumpers won’t win you any Italian design awards, but it will have the virtue of working.

        I love a design, like the geodesic dome, where spacy geometry actually *works*. But form should enhance function, not hurt it.

        1. Mirabile dictu, I agree with Brett (historical moment on the RBC here), though the specs (pavilion for display etc) call for something quite different from a charger. If what you want to do is capture sunlight, what you want is a big tarp-like thing to just unroll or unfold on the ground. Capturing wind and needing to be staked down is just what you don’t want. If it isn’t much bigger than the car, it’s a toy; sunlight is just too diffuse an energy source to charge a car practically from its roof, etc.

          Brett is also right about the difficulty of the folding trick. A bandsaw blade folds into a stable third of its diameter and stays put, in my two hands; bigger springy loops are really refractory.

          1. The best thing about folding bandsaw blades, in my experience, is that they’re not just springy, they’re sharp. 😉

        2. The trouble with geodesic domes – and I think with most kinds of architecture with
          non-vertical walls and windows – is that you’ve got a zillion small faces meeting
          at weird angles, and all those joints need to be sealed. There’s a reason why
          houses tend to be boring boxes, with overhanging eaves. Rain.

          Anyhow, totally agree with you that this thing with a massive springy carbon-fiber
          ring would be amazingly difficult to put away unless you had a 30-foot high four-armed
          giant, or maybe Doc Octopus.

        3. I stayed in a cottage once that was built in a geodesic dome. I say “in” because they basically constructed normal, right-angled walls inside the dome to put bedrooms in. The dome gives you a large interior space but it has walls that are useless for holding cupboards and plumbing and pictures etc.

          If you sat on the sofa in the middle of the dome and someone over at the edge spoke the voice sounded like the person was standing right behind you. Very spooky.

      2. One of the problems with PV collection is heating of the PV panels above optimal temperatures for efficiency. This design allows for passive cooling via convection, through an open framework.

  3. It looks both beautiful and ridiculous, though that doesn’t matter. What matters is whether or not it works.

    Regarding solar, I’m now almost exactly 1 year into having a PV system on my roof. It’s doing exactly what it was designed to do (produce ~100% of our power useage over the course of a year). So far, so good. It’s nice to have something working the way it’s supposed to. 🙂

  4. The folding trick is nice, but it looks as though the actual area of solar cells on this
    is pretty small. And they’re pointing in different directions, which means the total energy
    gathered per unit of solar cell area over the course of a day is going to be even smaller.

    But more seriously, this is going to catch the wind just like the butterfly wings which it
    resembles. So if you leave it alone, and a 10-20mph wind gets up, it’s going to blow around
    probably either roll off into the desert like a tumbleweed, or else flap and destroy itself.

    A more plausible answer would be a set of conventional flat panels clipping onto a folding
    frame with a mechanism to both track the sun, and fold up when there’s too much wind.

    1. You are trying to put the butterfly back in a rigid box where it doesn’t belong. Flexible PV makes all sorts of lightweight folding designs possible, some of which could be much more robust and wind-resistant than the subject here (slats, kites, balloons, sails, banners). Already flexible structures like tents and backpacks which already meet robustness criteria will incorporate PV straightforwardly. Admittedly the Solar Impulse plane, a piece of Swiss engineering even Brett may approve of, uses rigid noncrystalline PV cells, which up to now offer the best power-to-weight ratio, but this may well change.

      1. I read quite a few books about sailing. When a storm comes along at sea, you take those sails
        down, otherwise they get ripped to shreds pretty quickly (which saves you from having them
        break the mast). Wind force per unit area varies as the square of the wind speed – a 70mph
        gust is exerting roughly 49x more force than a 10mph breeze. You can probably find the video
        on youtube of a rather solidly-constructed steel wind turbine exploding under an excessive wind load.

        Putting flexible solar cells on a sail is a quick way of wasting money. The economics of solar
        cells work reasonably well when you install them in a sunny region, keep them pointing directly
        at the sun, keep them cool and reasonably dust-free, and take care of them so that they last 20+
        years, working 365 days a year. Buying expensive inefficient flexible cells and leaving them to
        flap around in the wind is going to be a loser. Especially if they spend a lot of time folded

        Now doubtless the kind of yuppie weekend trekkers who buy backpacking espresso machines are going
        to enjoy buying a $400 Gore-Tex jacket with built-in flexible solar cells to charge their iPhones
        when they’re a couple of hours from the trailhead. But we’re not going to see gigawatts from that kind
        of use.

  5. Ah, I see. The competition was not for a “portable solar charger”, as you claimed. It was
    for a portable pavilion for displaying the car. Not the same thing at all. The main goal
    was to look good. The use of photovoltaics is incidental to the actual purpose (and reinforces
    my suspicion that it’s shockingly ineffective as a solar charger).

    1. Yeah.

      Volvo’s “Switch to Pure Volvo” competition, organized by international architecture magazine THE PLAN, called for an innovative and original design for a temporary pavilion that expressed a “strong and creative identity” to showcase the car at fairs and open air presentations in Italian squares.

      Hardly something designed to charge EV Humvees out in Whereveristan. I also had a similar thought concerning wind.

      1. The post should be updated with a note to clarify this. Actually, I don’t think the whole conceit of the post (“jerry can of the future”?!?!) makes sense at all here. One is all about aesthetics and the other is all about practicality. Sometimes the two can be combined but neither the jerry can nor this PV adorned canopy does so.

        1. I find the Wehrmacht jerry can a fine piece of design. It was recognised as such by the Allies in WWII, who copied it early on. It was not a trivial innovation. In 1940 jerry cans gave the advantage in mobility to the Panzers, since forward tanks could be refueled using any vehicle available or even at a pinch by horses or men. British and French tanks at the time were refuelled from bowser trucks, which were vulnerable and tied to roads. For similar reasons the Pentagon takes deployable solar and wind energy very seriously today.

  6. A practical car that is self-sufficient with on-board solar energy is still science fiction. On-board solar that makes a measurable and cost-effective contribution to the car’s energy needs, however, may not be too far off. This rigamarole, foldable or not, does not strike me as promising.

    1. It’s a bad idea all round. Let’s suppose a typical car is roughly a box 9ft x 4ft x 5ft.
      That’s a surface area of 36sf on top, and 20+45 on back and sides (clearly the sun can’t be
      illuminating back and front simultaneously, nor left and right), for total 101sf ~ 9.6 sq meter
      Taking insolation as 1kW/sq meter, and solar cell efficiency of 15%, you have about 1.44kW,
      or about 2HP.

      I doubt that there’s any worthwhile net gain to be had, compared to reducing weight by taking
      the solar cells off, and optimizing the body contours for minimum aerodynamic drag. Plus
      improved engines such as Mazda’s SkyActiv, with higher compression ratio and tuned exhaust, which
      can get us beyond 40mpg.

      1. Your calculations are partially offset by the fact that many cars spend much more time parked in the sun than in motion. You are right, however, that on-board PV’s are not cost-effective with current technologies. I suggest only that they might be plausible in the future.

        1. Yes, they spend time parked in the sun. And to store significant amounts of energy
          from that time you would need a heavy bulky battery, as in current electric and
          hybrid cars. Which gets us back to whether the extra weight (and possibly bulk,
          and related aerodynamic drag) of the solar charge/store system leaves you with
          any net benefit at all, compared to a lighter, more aerodynamic, and much much
          cheaper vehicle with a simpler gasoline or gasoline/electric hybrid engine system.

          I’m a big fan of putting solar cells on south-facing roofs. That’s what they’re
          really good at. But I’m also a pretty big fan of modern internal-combustion engines:
          with high peak power, good power-to-weight ratio, and excellent energy storage-per-kg,
          together with 100 years of high-volume manufacturing expertise, they’re really hard
          to beat in cars. You don’t want a V6 engine powering your house; you probably don’t
          want solar cells on your car.

        2. I think even the “plausible in the future” is a pretty big stretch.
          The surface area of the cars isn’t going to get much bigger; the efficiency
          of solar cells isn’t going to increase radically (maybe you’ll get 20%,
          rather than the 15% I used, but not much more); so the total power
          available isn’t going to get much higher. And that’s really the whole
          argument: even if the cost of the solar cells drops to zero, they don’t
          make enough power to be very interesting on a car.

          Rechargeable vehicles make sense; plugin hybrids make sense; onboard
          solar cells don’t.

  7. A number of problems/queations have already been mentioned: whether one person can deploy and stow it; whether it’s sturdy and effective when deployed; whether it’s got sufficient photoelectric surface area when deployed, compared to its total size and complexity; whether its storage volume is too much; likely others.

    But I think people are failing to ask a much more basic problem: where the heck are you going to deploy this contraption? Answering that question changes things dramatically.

    This device, when deployed, is massive and obstructive. It can not be used along any road in the world, and not in any remotely efficient parking area, either. It’s only useful if you can leave your car isolated from all other vehicles, obstructions, and passersby by about a car-length in any direction. This is actually quite a specialized and unusual circumstance – and it’s one that has important implications. Once we’ve hypothesized that you’re taking your car into essentially deserted areas (which would also explain why it’s worth carrying an expensive, bulky, and heavy photoelectric device rather than connecting to the grid), the whole contraption becomes ridiculous. Under the circumstances where a huge unfolded solar array becomes practical, it also becomes practical to select for your parking space a gentle slope facing the equator, and lay out solar panels along the ground. A collection of flat solar panels with short cables can be more easily and efficiently stowed and need not be greatly more time-consuming to stow and deploy than this device, and should be massively more effective per dollar and per stowage requirements. Won’t be as artistic, though.

  8. Brett’s an engineer now?

    I’m not assuming (as perthaps Brett is) that it is supposed to be deployed on a moving vehicle, so it looks sort of brilliant to me, collapsible as a folding reflector, yet with enough area to collect a lot of power quickly. It might give you a little challenge in windy conditions however.

    1. Brett’s been an engineer for 2-3 decades now. Tooling, mostly progressive and transfer dies, though I do a bit of minor automation, too. (I did spend several years designing extrusion dies for thermoplastic elastomers, mostly Santoprene, at one point.) The Whirlpool Duet clothes drier at one time had a stamped hinge on it that was my work.

      I’ve even got a couple of patents, though as a tooling engineer, most of what I do is proprietary rather than patented, since it never leaves the door of the factory.

      Why would you find this shocking?

      1. “Why would you find this shocking ?”

        I’m shocked that you would work on anything “progressive”. Couldn’t you find a job designing reactionary dies ?

  9. This was not a brief from the US Army to design a brute-force object where function was everything. The jerry can is an ugly, kludgy piece of work, as is the original Humvee, as are most military designs. All that matters are the performance specs.

    In real life (as opposed to military-bureacratic life) we want things that elevate our sense of what it is to be human, to engage meaningfully with the world of things. Many of us love a well designed object, whether it’s a Moleskine sketchbook, a Ducati motorbike, a Japanese Raku tea set, an iPhone, a piece of architecture. Jorn Utzon’s Sydney Opera House is masterwork. So is the Bilbao Guggenheim. But these are not entirely practical buildings. Rather, they’re a melding of the practical and the aspirational.

    So it is with this pavilion. A private car manufacturer wanted a beautiful display system that also maybe generated energy and could fold up into a small shape. That’s what they got. The thing is as beautiful as a sea creature. But not only that: it generates energy.

    The problem I have with engineers is that they frequently kill the beautiful speculation with bureaucratic specificity, even when it’s not needed.

    1. “In real life…we want things that elevate our sense of what it is to be human, to engage meaningfully with the world of things. Many of us love a well designed object, whether it’s a Moleskine sketchbook, a Ducati motorbike, a Japanese Raku tea set, an iPhone, a piece of architecture.”

      The Substance of Style:How the Rise of Aesthetic Value Is Remaking Commerce, Culture, and Consciousness

    2. Well, OK then – but I’ve clicked the link and I’ve got no idea what the brief was. It wasn’t to be a sensible, functional provider of power; apparently, it was to better display the car at auto shows. But it makes no sense that way: it is perhaps an interesting, if blandly monochromatic, sculpture built around a car (and more interesting in some of the pictures at the link, which aren’t as symmetrical), but as a means of displaying the car it makes no sense – it obscures the car, after all. It might attract attention, I suppose. Really, the whole point rather escapes me.

      1. Luckily, aesthetics are subjective. You may not like it, but I and others do—and not only for aesthetic reasons. And design, like other fields, is not a precise or linear art. Meaning that it is highly speculative and exploratory. Or, as Dave Hickey said, “Art and architecture are practices, not sciences. Science aspires to universal application. Pictures and buildings [and industrial designs] need only work where they are.”

        Also, blandly monochromatic? You may have missed the trend in the design world over the last ten years, but one of the most influential architects in the world right now, Kazuyo Sejima, only designs buildings in pure white. And have you been to an Apple store lately? Like it or not, “blandly chromatic” is where we are design-wise (and I prefer the phrase “clean, precise, and without artifice.”

    3. The jerry can is not kludgy at all. It’s a brilliant design, with careful attention to details:

      1) The two halves are stamped, and there’s a single weld around the middle. Competing designs
      used more parts, more welds, and had the welds on the edges and corners where they were
      more vulnerable to damage.

      2) The stamping allowed indented ribs on the sides, which both strengthened the can, and gave
      flexibility for expansion with temperature changes.

      3) The lever-operated cap allowed it to be opened and closed quickly and securely without tools
      (competing designs used a screw cap, needing a spanner).

      4) The built-in spout allowed it to be used without a funnel.

      5) The spout contained an air vent to allow smooth pouring.

      6) The three handles on top allowed a variety of handling strategies to be
      used comfortably: one person carrying two full cans by the middle handle,
      one person carrying four empty cans, two in each hand with the side handles,
      a line of people passing cans.

      Brilliant engineering, and not at all kludgy.

      AFAIK, the design has survived 70+ years, with few further improvements other
      than the use of novel materials.

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