“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)

Saturday, August 24, 2013

The (probably) last post on regenerative braking

I've posted a couple of times on regenerative braking in my CT200h. This will, I expect, be the last. In the previous post I estimated that regenerative braking on a trip saved me about 5.9% of the gasoline I'd have used without it. I decided that a better test would be a full tank, so I monitored all of the regenerated watt hours for my most recent tank. Since it's kind of a pain in the rear, I'm not going to keep it up.

Calculating in a more efficient way than the very detailed way in the previous post, the results are as follows:

  • The measured economy by miles divided by gallons at fill-up: 50.60
  • The calculated economy without regenerative braking: 47.55
  • Gallons per 100 miles: 1.976
  • Gallons per 100 miles without regenerative braking: 2.103
  • Per cent fuel savings: 6.04%
Not much different, so I think that it's safe to say that regenerative braking saves about 6% of the fuel I'd otherwise use.

I'm a bit surprised that the number is that low. In this post I discussed some of the factors that make hybrids so much more fuel efficient than their non-hybrid cousins and the regenerative braking was one of the factors I considered most important.

There is no non-hybrid CT with which to compare the fuel economy. I went to the DOE fuel economy site for the Camry (the four cylinder version)  and for the Camry hybrid. Using the combined highway and city estimates for each (28 m.p.g. and 41 m.p.g. respectively) it looks like the hybrid, per the government's test protocol, will use about 31.7% less fuel over any distance. It's reasonable to infer that, while the regenerative braking is a significant fuel saver, other factors (operating more frequently on more efficient areas of the engine map, capturing energy while coasting, automatic engine shut-off where appropriate, etc.) are at least as important.

Sunday, August 18, 2013

A response to "it's not hurting you, what do you care?"

Along with shaking my head at homeopathy, faith healing, etc., another guilty pleasure of mine is reading the amazing developments chronicled at the free energy site "Pure Energy Systems News." The site is primarily devoted to various manifestations of energy from (the vacuum, cavitation, magnetic dipoles, zero point, etc. ad infinitum), though its publishers are also hugely invested in pretty much any conspiracy theory out there.

Without going into a lot of detail, the site got excited over a supposed live demonstration of a "self-looped motor generator" developed by one Charles Pierce, who claims a Ph.D. from Bethany University (which never offered either doctorate or science degrees and is now defunct) in "Thermonuclear Reactors." Self powered energy devices (and their their pre-electricity ilk) have been around a long time and the idea here, as usual, is that you use batteries to start a motor that spins a flywheel that runs a generator that turns the motor that spins the flywheel that runs the generator that .... you get the idea. Such schemes have been around for centuries (overbalanced wheel gravity engines are pre-electronic examples) but now they typically come dressed up in jargon involving "quantum tunneling," "resonance with ambient energy," etc. You can make people believe in some pretty bizarre contraptions by throwing the word "quantum" into your explanation (albeit, quantum mechanics is, in fact, quite bizarre in any case).

Anyway, the live demonstration was to have taken place August 8, and Sterling Allan, the site's proprietor, blogged the failure to launch. I (along with others) made a sarcastic comment. The moderator responded with the usual "what harm does it do?" The following was my reply (as of this writing, it's still in moderation):
Your contention that "there's nothing to lose" is, in my opinion, very much false. If I want to have the hobby, for example, of throwing the i-ching or drawing tarot cards, or whatever, that's my business and it's no more harmful than collecting baseball cards or birdwatching. If I choose to guide my life by such activities, that's also my business. But when I try to convince the naive that i-ching or tarot really can foretell the future and then I motivative them to make life decisions based on the chance arrangement of printed cardboard or yarrow stalks, I've crossed the line. When I solicit money to inflict such nonsense on the gullible, I've crossed the line. 
So-called "free energy," given the available evidence (that is, none), is of a kind with i-ching and tarot. People want it to work, I want it to work. But I'd also like it if I could rely on yarrow stalks to assist me in making the best decision at each stage of my life. Sadly, neither has been shown to work and there is excellent rationale and mountains of evidence, dating back hundreds of years, to show that neither can work. Yes, people can make their own decisions on what to do with their lives, their intellectual, physical, emotional, spiritual, and financial resources but, for all Sterling's, Hank's, your belief you are doing actual harm when you lead them down these paths. 
This doesn't even address the many people who have been taken in and lost financially on such schemes (though there are many, as you well know) and I don't (at this point anyway) accuse Mr. Pierce (I will NOT use the honorific "Dr." as it's clear that that's made up B.S.) of running a financial con. Whether or not Mr. Pierce actually believes in his system is an open question for me. People who truly think they've succeeded in producing a free energy device are the most mysterious to me. Con men and hustlers I get. Those who brilliantly design within the constructs of ever-evolving known physical theories, I get. Those who occupy the middle ground (assuming there are such people - not being psychic, of course, I don't know) I don't get. 
Finally, to quote myself, "I've frequently seen (at PESN, on my blog, and elsewhere) a troubling retort to physics based debunking of alleged miracle fuel saving devices, miracle cures, etc. The retort is along the lines of 'I'm sure glad I never took physics so that my view isn't limited by the dogma of traditional physics. I can be open to new ideas.' It's sad, so very much is possible within what we know and, though we certainly don't know everything, we know a lot more than nothing. And knowing what is and is not possible, the 'man will never fly' and 'aerodynamics says bumblebees can't fly, yet they do' tropes aside, enables efforts to be directed at things that have, at least, the possibility of paying off.
Update: A somewhat edited version of my comment made it out of moderation.

Monday, August 12, 2013

More on fuel saved by regenerative braking

I published a post regarding how much energy is captured in the regenerative braking system in my Lexus CT200h hybrid. After some discussion with commenter Gabriel Grosskopf, I estimated that about 59% of the energy available (after subtracting the energy used to overcome aerodynamic drag, rolling resistance, and internal friction) was recaptured and used to charge the battery.

Since I (and others) have represented that the regenerative braking system is among the key reasons that hybrids achieve superior fuel economy, I decided to check the actual impact.

My round trip commute, generally downhill in the morning and uphill in the evening, is 62.46 miles and, for the last 10 fill ups, my average m.p.g. has been 52.47. So, to make my commute, I use, on average 62.46/52.47=1.190 gallons of gasoline. My display showed me today that my regenerative braking system added 700 watt hours or 2,520,000 joules to my battery that I could use for accelerating, hill climbing, etc. If I assume my electric motor is 90% efficient, I put 2,268,000 of these joules to work.

A gallon of gasoline (reformulated blend in this case) has an energy upon oxidation of 111,836 btu or 117,993,000 joules. I estimate that my internal combustion engine is about 25% efficient, so I put about 29,498,000 of these joules to work. My 1.19 gallons thus provide 35,103,000 joules that propel my vehicle (the remainder being lost as waste heat in myriad ways).

If I assume that I used all of the energy my brakes provided, then 35,103,000 + 2,268,000 = 37,371,000 joules of work were done to propel my car. Then, dividing by 0.25, I can estimate that 149,484,000 joules of oxidized gasoline would have been necessary to do this work. This is the energy in 1.267 gallons. Dividing this into 62.46, I find that the fuel economy without the regenerative braking would have been about 49.30 m.p.g. The regenerative braking thus upped my m.p.g. by 3.17.

As I've often said, it's much more intuitively informative to discuss gallons per mile, or gallons per 100 miles. So, the regenerative braking took me from 2.03 gallons per 100 miles to 1.91 gallons per 100 miles. So it takes me 5.9% less fuel to go a given distance, ceteris parabus.

There's no question that I'm carrying a lot more significant figures (apologies to John Denker) than are warranted by the precision of my data, but I think that the figure I've determined is probably in the ballpark.

Saturday, August 10, 2013

Greenwashing Hall of Fame nominee

The Greenwashing Hall of Fame doesn't exist (to my knowledge) but it ought to. I've posted on a potential candidate or two myself. I may set it up and solicit nominees through my blog. The one I have in mind today was brought to my attention by BBC World Service on Sirius XM in my car. It was, seemingly, an advertisement for Pavegen Systems thinly disguised as a news feature (though I'm sure BBC doesn't think so).

Pavegen manufactures tiles that use piezoelectricity (I think it's safe to assume, though the site doesn't say) to "harvest" electricity from motion. They have a variety of posts for tiles installed in offices, at rail stations, schools and colleges, etc.

Specifications are given nowhere on the site, so I've had to use information from secondary sources (though I should be able to take a look at real-time generation at an office during regular hours by going here).

Looking at a couple of videos it looks like a tile deflects maybe a quarter of an inch (call it 0.006 meters) under the weight of a normal size adult male, say 76 kilograms and a weight of 750 newtons (round numbers here, they're just rough estimates). So the work done by 750 newtons through 0.006 meters is 4.5 joules. I'll assume that the tiles are 67% efficient at turning this work into electricity, making 3 joules available per step.

The source linked in the previous paragraph says that, at the West Ham Station installation, each tile got about 5 steps per minute and that a tile will produce about 75 watt hours of electricity "on a good day."  The information is confusing because it says that 50 steps per minute yields 6 watts which, in 24 hours, would yield 144 watt hours. But never mind. OK, back to the calculations. 3 joules times 5 steps per minute/60 second per minute is 0.25 watts. So, each hour would deliver 0.25 watt hours. Doing this for 24 hours would yield 6 watt hours. 50 steps per minute would yield 60 watt hours, close to the 75 cited above.

Anyway, the 6 watt hours would cost me 0.006 kilowatt hours * $0.16/kilowatt hour, or $0.00096 (96 thousandths of a penny). Though the price of a tile isn't given, it's pretty certain to take a very long time to pay off financially at a penny every 10 days or so.

I take something like 5000 steps per day, and would generate 5000*3=15,000 joules, or 3.6 kilocalories (that is, food type calories) were every step on a Pavegen tile. I step about 2.5 feet per step, so 5000 steps is 12,500 feet or about 2.4 miles. Here, we read that a 180 pound man burns about 100 kilocalories per mile as he walks, so I'd burn about 240 kilocalories (in other words, 240 kilocalories of food would be eaten) to walk this distance. I'm sure it's not exact, but here we read that, in order to feed me with 240 kilocalories, 2,400 kilocalories of fossil fuel is used.

So, putting it together, if the Pavegen system harvested the energy from every step of my walking, 2,400 kilocalories would go to produce 3.6 kilocalories of electrical energy. Of course, this isn't fair to Pavegen since I'd also, presumably, have gotten where I was going. On the other hand, I paid for the food to do that walking.

In the end, generating electricity through human effort is just not very efficient in comparison with other methods. If we're using muscle power for exercise and the effort would otherwise simply heat the environment, there may be a place for it (though I doubt it would ever pay off financially) but as a green power source, sorry, it's no sale.

Sunday, August 04, 2013

Gadgetman Groove update

Back in February of 2011, I wrote a post on the Gadgetman Groove, a modification purported to provide spectacular gains in fuel economy and power. And when I say "spectacular," I'm talking about double the m.p.g. and more. As it happens, my Groove page turns up on the most visited statistic fairly frequently. I suspect the visitors may not read what they'd hoped to but, as the Apostle Paul wrote in his first letter to the Corinthians, the time comes when we must "put the ways of childhood behind" (New International Version 1 Corinthians 13:11).

In any case, seeing that post come up as one of my most frequently visited piqued my curiosity and I paid Ron Hatton's (the inventor of the Groove) web site another visit, where I found the following quote: "The EPA tells us more than 60% of the power in your fuel is wasted in the exhaust." Does the EPA actually say such a thing? Well, sort of...

The EPA (and anyone else with a degree of knowledge of engineering thermodynamics) will
tell you that much of the chemical potential energy released in the burning of fuel in the cylinders of an internal combustions engine exits the engine as low grade waste heat in the exhaust, through the radiator, radiantly from the engine, and elsewhere, and 60% is really a very low number for that "waste" in an otto cycle engine. Such losses in a heat engine (or any engine) are an inevitable consequence of the second law of thermodynamics.

Ron Hatton, though, implies that this waste is fuel that isn't burned in the engine. Or, perhaps is burned in such a way as to not produce motive power - I'm not really sure. He has a fourteen minute explanation of its working principles (as he understands them) here. At one point, he mentions that the "ball" of high pressure air created by the groove is a million times more dense than ambient air. That would be ~1.22*10^6kg/m^3~. Yes, the air is so dense that a cubic centimeter of it weighs (ok, has a mass of) 1.22 kilograms or weighs (here at the Earth's surface) 2.7 pounds. This is about 90 times as much as a cubic centimeter of mercury weighs! If it's an ideal gas (it's not, but we're talking order of magnitude here) its pressure is on the order of ~3*10^{13} Pa~ or ~4*10^9 pounds/inch^2~ (where I've speculated that the temperature is around 470 K).

I actually watched an online "talk show" called "Talk For Food" wherein Adam Abraham holds forth on a variety of rather outré subjects. In the subject episode, Abraham interviewed Gadgetman Ron Hatton and had the groove installed in his 1993 Lexus. In the course of the interview, Hatton claimed as much as 90% of the fuel going into a typical internal combustion engine is not burned in the cylinders to produce motive power. Rather, it's burned in the catalytic converter or exhausted unburnt.

This is irrational. A gallon of gasoline releases about 132 MJ (megajoules)/US gallon upon complete oxidation. Let's assume that 13.2 (10%) of those potential MJ are actually released in consuming a gallon, and the vehicle goes, say, 18 miles on that gallon at 55 m.p.h. Let's further, generously, assume that the internal combustion engine (ICE) can utilize 30% of these 13.2 MJ (i.e., the ICE is thermodynamically 30% efficient) then we can calculate that abut 4.5 horsepower is what's required to push this vehicle down the road. Sorry, that dog don't hunt.

Hatton had an analyzer hooked to Abraham's exhaust for a before and after test. The footage showed somewhere around 3,900 ppm (parts per million) for hydrocarbons in the exhaust before installation of the groove and 0 (yes, zero) after. Now, I've not seen any independent testing of the exhaust stream, so I can't say that these results have been replicated (nor that replication has been attempted and failed).

I don't claim that the Groove doesn't work, or that it provides no benefits. I simply state that all the "I think I'm getting about 28 m.p.g. and I used to get 12 m.p.g. and it sure does run smooth now" anecdotes on youtube provide no evidence that it does provide benefits.

But, at a broader level, I ask you: If this simple modification could be so effective, why aren't all the vehicle manufacturers beating a path to Hatton's door to license the (patented) technology? Can the oil companies really afford to pay them off? Imagine that Chevy could announce a Chevy Cruze that achieved 45 m.p.g. or even 60 m.p.g. and that car cost not a penny more to manufacture (the groove would, after all, not be installed by auto workers with Dremel tools as Hatton does it).

Anyway, I'll answer a question that comes up when I write about such matters and then make a comment on a comment I've seen on my blog posts and elsewhere. The question: "why do I care? The customers are satisfied, Ron Hatton seems like a nice guy." I care for a couple of reasons. First, the rising (worldwide, if not in the US) demand for petroleum based transportation fuel coupled with our stagnant ability to provide it makes critical analysis of possible efficiencies crucial and the discounting of pixie dust pivotal. Second, the gullibility and inability to think critically of the US public is disturbing and each example troubles me.

As to the comments, I've frequently seen (at PESN, on my blog, and elsewhere) a troubling retort to physics based debunking of alleged miracle fuel saving devices, miracle cures, etc. The retort is along the lines of "I'm sure glad I never took physics so that my view isn't limited by the dogma of traditional physics. I can be open to new ideas." You'll see such a comment on my original Gadgetman post. It's sad, so very much is possible within what we know and, though we certainly don't know everything, we know a lot more than nothing. And knowing what is and is not possible, the "man will never fly" and "aerodynamics says bumblebees can't fly, yet they do" tropes aside, enables efforts to be directed at things that have, at least, the possibility of paying off.