“Be kind, for everyone you meet is fighting a hard battle” - Often attributed to Plato but likely from Ian McLaren (pseudonym of Reverend John Watson)

Friday, November 29, 2013

Ack! ANOTHER "capture the energy of walking/driving" system

I really don't want to turn this blog into a debunking site but some things just must be said. Here I described a completely impractical system for "capturing energy from pedestrians." And now we find an article from Science Daily about Mexican entrepreneur Héctor Ricardo Macías Hernández, pictured at left, who's developed yet another system for capturing energy from passing traffic - vehicular or pedestrian.

It apparently consists of a traffic wearing surface that sits five centimeters above street or sidewalk level. Passing traffic squeezes a bellows, compressing air into a tank (the linked article says "...where it is compressed..." but I don't imagine that that's accurate) from which it is expanded into a turbine to generate electricity.

Think about it. Your engine (either that of your vehicle or of your metabolism) is squeezing air into a tank. This work will reduce your gas mileage (or use your food energy) as your vehicle or your feet do the work of compression. There is no free lunch here. I'm surprised to see it in Science Daily which, although it is sometimes prone to exaggeration, usually doesn't publish nonsense.

There are no figures given, either in the Science Daily article or the articles linked from there, so I don't know what kind of traffic would be claimed to generate what kind of power. But I do know that, whatever the amount generated, it would be more efficient to burn natural gas in a turbine. Both vehicular internal combustion engines and human metabolisms are inefficient and compressing air is a lossy process. I'd love to see figures for this but it's yet another candidate for my prospective Greenwashing Hall of Fame. Yes, I know that the term "greenwashing" is typically applied to deceptive ad campaigns but I think it's equally applicable to deceptive products.

Update: In thinking about it, I suppose that one could concoct a scenario wherein a developing country with few energy resources would rather have the "rich" who own cars spend some of their energy (i.e., gasoline or diesel) purchase on providing energy for township than purchase natural gas, oil, or coal and then charge the poor residents for the electricity or pay for the fuel with taxes. But even there, better a gasoline tax with the proceeds used to pay for more efficient energy generation.

Solar panels on a truck?

I took my family to the LA Auto Show yesterday. Despite studies and articles contending that young people today are not so attached to automobiles, my son is absolutely captivated by them. He knows the makes and models, what he'd like, how he'd modify it, etc. I knew he'd have a great time and he did. I wanted to see developments in electric vehicles, plug-in hybrids (PHEV), etc., both production and concept.

I noted a pickup truck with a tonneau cover consisting of a solar panel and wondered about its practicality. Neither the Via Vtrux pickup (a series PHEV) nor the SolTrux panel option are in production, which is anticipated for 2014. It's a nice looking truck.

But is the solar panel practical? I have a Jeep pickup into which I've installed a 32 gallon water tank and other items designed to let me be self-sustaining in the Mojave, Sonoran, and Great Basin deserts of the Southwest. Where better to capture the sun?

So what are the appropriate numbers? We'd like to have battery capacity, dimensions and efficiency of the solar panels, and the claimed output. Here we find that the battery pack is 22 kWh. The dimensions of the panel array aren't given. but the standard bed is 78.7" long. The width isn't given but might be 65". The larger panel is stated to be 800 watts.

I see here that, in March (about average) I can expect on the order of 5 kWh/(m^-2*day) (kilowatt hours per square meter per day) for a panel mounted horizontally as it would be on a tonneau cover or roof rack. If I assume that the panels are 72" X 60", or 2.8 m^2 they should intercept 2.8*5 14 kWh per day. At 20% efficiency, I should get (surprise) 2.8 kWh/day. Assuming that I'd never let the battery pack below 20% charge, it would take 17.6/2.8 or a bit over 6 days to fully charge the battery. And the 22 kWh is represented to be good for 35 miles (though my desert miles are VERY hard on energy use). At that ratio, a day's worth of sunshine would take me (2.8/17.6)*35 or about 6 miles and probably a lot less in the rugged terrain where I'd be operating.

I suppose that, were I (through incredible stupidity or possibly a punctured fuel tank) out of gas and stranded, I could drive six miles per day for however many days it took to get to civilization (a very long way from the places I go). The fact of the matter is that it simply takes a lot of square meters to provide significant power. Verdict? NOT worth the estimated $3,000 price for the panels.

Update: Here's a clickable link to the article cited in the comments by Anonymous.

Saturday, November 23, 2013

Embarrassed to be conservative - a (sadly) continuing series

And yet, within MY definition and one that I will defend, I still am.

This Does Not in Any Way Imply That All Climate Deniers Are Obnoxious Blowhards | Climate Denial Crock of the Week:

'via Blog this'

A digression - should interest in sci fi be a qualifier for gifted programs?

Since my blog muse has, hopefully temporarily, abandoned me and my calculations regarding the energetic plausibility of carbon dioxide sequestration via carbonate minerals is taking much more time and effort than I'd anticipated, I'm going to go completely outside any subject space I've dealt with.

As a youngster, I read a LOT of Isaac Asimov's writing. While Asimov is very well known for his science fiction, I read none of it. What I read were his essays, which covered such an amazing breadth of topics that it's hard to believe that a single individual could do it. However, one that I read rankled.

Asimov was clearly a prodigy and, back in my youth, some regarded me as such. All that ever interested me was science and math and I was fortunate enough to attend a progressive (in the academic rather than the political sense) school. I was accelerated, I was offered training in scientific investigation, and I was offered the opportunity to choose what I studied, at least to an extent (I managed to squander most of this advantage upon reaching college but that's a story for another time).

But Asimov wrote an essay (I can't find it but remember it distinctly) suggesting that school children be assessed for accelerated learning or "gifted" (a label sometimes applied to me) programs based on their level of interest in science fiction. I found it then and find it now to have been pretty self-serving and self-aggrandizing for such an otherwise objective thinker.

I started both Asimov's "I, Robot" and his "Foundation" series and finished none of the stories, finding them much less interesting than reading and studying science and mathematics. I could likely count the science fiction stories I've read on the fingers of a hand (and I wouldn't need the thumb). I read "The Hobbit" and found it quite boring, and made it through two and a half of the "Lord of the Rings" trilogy (at Northwestern University in the early '70s, at least in my circles, it was a scarlet letter offense not to have read these - I had a fraternity friend who prided himself on reading the entire trilogy every year). Halfway through the third novel, I concluded that "this sucks, I'm reading it only because I'm supposed to" and put it down, never to complete it. Yes, I realize that Tolkien's works are fantasy rather than science fiction but I'm sticking with the point.

What point is that? It's not really clear, but it's a rant I've kept inside for decades. The trailers for "The Hobbit - The Desolation of Smaug" are popping up and brought it to mind. I've not seen any of the previous Tolkien adaptations (for the matter of that, I saw the original "Star Wars" in 1977 and have seen none of the prequels or sequels). I did watch all of "Star Trek" and some "Star Trek TNG" so I guess I'm not completely immune, but these shows could almost as well have been done as westerns!

In any case, I'm not at all sure that Asimov's razor (as I'll call it) would be the appropriate metric for determining the suitability of elementary school students for gifted programs (assuming such programs still exist in this day of No Child Left Behind-based teaching to the test). I'm sure it's a reflection of both my ego and my ability to hold a grudge that an essay I read, probably, over 40 years ago still causes resentment but perhaps this post will allow me to finally let it go!