“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)

Sunday, September 12, 2010

More on Moller International and the "Skycar"

Back in March of 2009, I made a couple of posts (here and here) about the Moller Skycar. I questioned some of the claims made for the vehicle with respect to fuel economy and speed. The other day, a comment on the second of my posts related to Moller mentioned that my posts had been discussed on the Moller blog site. I'll quote the comment by a blog visitor and the answer by Bruce Calkins, Moller International's General Manager, in full:





A long time skeptic  - Query re: concerns about range and fuel efficiency
I was curious to know what Moller International thinks of the speculations by this blogger here: http://hamiltonianfunction.blogspot.com/2009/03/moller-sky-car.html and here: http://hamiltonianfunction.blogspot.com/2009/03/horsepower-fuel-efficiency-and_31.html I'm not sure I agree with all his assumptions, but he makes a pretty damning case. I would be interested to here the company's reaction.




Bruce Calkins  - Skeptics talk about fuel economy of the Skycar
There is a saying that a little knowledge is a dangerous thing. The blog entries seem to fit into this category. While the maximum hp and burn rate are correct, the assumption that we remain at that rate for anything more than the few short seconds while we are operating in VTOL mode is not. Our hp requirement in cruise is about 120 hp, with the corresponding fuel burn rate. Range projections are based on the reduced fuel burn rate. We are currently evaluating a hybrid fuel-electric propulsion system that might reduce the total installed power requirement replacing it with a temporary electrical "boost" system for the VTOL-mode operations. If you would like a more detailed paper on the subject, email me.
 Before I comment on this I want to state that Dr. Moller is, without a doubt, a brilliant man and an extraordinary aerodynamic engineer. Certainly, he's far beyond my expertise. That said, he and those with whom he works have a long history of making claims that are never fulfilled. A good place to start reading about this aspect is at Wikipedia's Skycar page.

Now, Mr. Calkins is stating that the Skycar will cruise using 120 horsepower. The Skycar specifications page states that the cruise speed at 25,000 feet is 305 m.p.h. and that "max mileage" is greater than 20 m.p.g. It's not stated what airspeed is utilized to achieve this mileage. It may be very much lower than 305 m.p.h. In my airplane, the maximum range airspeed (that is, the airspeed at which I can achieve the greatest number of miles per gallon) is about 24% lower than normal cruise speed. Interestingly, on another page the claim is that "M400 Skycar can cruise comfortably at 275 MPH (maximum speed of 375 MPH) and achieve up to 20 miles per gallon on clean burning, ethanol fuel." I'll use this and supplement it with information in a paper hosted on Moller's web site. However, one thing I note is that none of the referenced pages give a categorical statement that the Skycar can achieve a cruise speed of, say, 275 miles per hour while it's getting 20 m.p.g. Instead, statements such as that quoted above can be backed away from by saying "well, yes, it can get 20 m.p.g. at the minimum point on the thrust required as function of airspeed curve," typically not far above the maximum L/D (lift/drag) ratio airspeed.

But let's proceed. We'll start with the assumption of steady flight in cruise. The conservative claim above is that the Skycar will do 275 m.p.h. in cruise and Calkins states that it uses "about 120 horsepower." OK, as I've mentioned any number of times, power is equal to force times speed, so force is equal to power divided by speed. The Google calculator makes this division and  handily converts the units to newtons, yielding a thrust of 728 newtons.

Now, as we learn in high school physics or in airman ground school, for an airplane in unaccelerated flight (as the Skycar would be under the cruise condition assumed here) thrust=drag, and lift=weight. Hence, we're considering a total (lift induced plus parasitic) drag of 728 newtons for an aircraft travelling at 275 miles per hour. We need to determine if this is plausible. Without a lot of mathematical derivation, it's pretty easy to show that, in unaccelerated cruise flight, Thrust=Weight/(Lift/Drag). That means that Lift/Drag=Weight/thrust. Here we have (using 2400 pounds or 10,676 newtons as the "gross weight") that Lift/Drag=10,676/728=14.66. But the specifications page referenced above has the so-called maximum L/D (the maximum ratio of lift to drag) as 12.5. Now, this maximum ratio is at a specific airspeed, any other speed will produce a lower L/D ratio. 14.7 cannot be achieved.

The Moller International web site does not give sufficient data to go much further (wing span, wing area, flate plate area, etc.) so I can't really do much more than this. I will say that the figures claimed by Moller International are likely not outlandish but, in my opinion, they are very significantly exaggerated.

Monday, September 06, 2010

Unit ambiguity in the New York Times?

I've made several posts (here for example) decrying people's cluelessness with respect to scientific concepts and, in particular, with respect to units. But do we have an example in the New York Times? I follow the New York Times Twitter feed (nytimesscience) and read the following: When It Comes to Car Batteries, Moore's Law Does Not Compute http://bit.ly/bSuX3e. Naturally, I clicked on the link and it took me to an an article on the rate of advance in battery technologies, both with respect to energy density and charging rates. All very interesting, and the interview subjects were from IBM and Better Place.

But about midway through the article, I read the following:
He illustrated the challenge of building a battery with the energy density of gasoline by recounting that it took 47 seconds to put 13.6 gallons of gas in his car when he stopped to fill up on the way to San Francisco. That’s the equivalent of 36,000 kilowatts of electricity. An electric car would need to pump 6,000 kilowatts to charge its battery.
Does this make sense? Let's parse it.13.6 gallons of gasoline contains (at 125*10^6 joules/gallon) 1.7*10^9 joules. Putting this in the vehicle in 47 seconds yields a "rate of energy transfer" of 1.7*10^9 joules/47 seconds, or 36.2*10^6 joules/second or just over 36,000 kilowatts. OK, so far so good.

But where does the 6,000 kilowatts come in? Well, the internal combustion engine (ICE) in the gas powered car might use energy at something like 22% efficiency, so the 1.7*10^9 joules might translate to 3.74*10^8 joules of useful work. OK, an electric motor with the power to drive a car will typically have a minimum efficiency of 92%, so that means that we'll need 3.74*10^8/.92 = 4.07^10^8 joules of electrical energy put into the battery. Doing this in 47 seconds yields a charging rate of 8.6*10^6 watts or 8,600 kilowatts. Not really so far off, and I guess that that's where the figure came from.

Stepping back, it's a very good illustration of why we love fossil fuels. Suppose IBM and Better Place succeed in creating a lithium air battery with the required energy density and ability to accept a charge at the rate described above. Now, imagine a "charging station" with, say, 4 cars charging their batteries at the rate of 6 megawatts, and imagine that you're at a corner with another station across the street doing the same. As I drive around, this is not at all an unusual circumstance at some times of day. So, at this corner, we'll need to be able to supply at least 48 megawatts of electrical power. That's about 5% of the power from a gigawatt generating station (this is a big facility). Getting energy from a power plant to a charging station at this rate, with the ubiquity of today's gas stations, is an incredibly difficult transmission problem

As I've demonstrated in a previous post, I believe it will be possible to install sufficient capacity to supply electrical energy to a fleet of electric cars. But the ability to deliver it at an acceptable rate to batteries that can store it is definitely the sine qua non of the widespread adoption of electric vehicles.

Sunday, September 05, 2010

The Chevy Volt - is it for me?

I've already posted about the Chevy Volt and the mileage claims made for it. But the time is coming to replace the Land Rover LR3 HSE that I've been driving since 2006. The Land Rover is owned by my Company and, in the current economic environment, there's little excuse for being provided with such a vehicle. I've mentioned my partner and the BMW X5 he drove, also owned by our Company. He's purchased a Toyota Prius (NOT company owned).

So, I'm wondering what to drive. The choices really seem to be the Nissan Leaf, the Volt, and the Prius. I'm leaning against the Leaf because it's range is about 100 miles on a charge and, though my commute is about 62.5 miles round trip, I sometimes need to go to meetings from the office or go to places other than the office from home and there's no infrastructure to charge the Leaf "on the road."

The Prius is all well and good but, well.... my partner got one. So, what about the Volt? It has much to recommend it for my application - though it's only estimated to get 40 miles on a full charge prior to using the internal combustion engine (ICE) to supply energy to the electric motor and my one-way trip to work is about 30 miles, I can charge it at the office and use the ICE only in the circumstances described in the previous paragraph. So, decision made, right?

Not so fast. This vehicle has an MSRP of $41,000 for the base model. A tax credit (not sure how the money is actually collected) of "up to" $7,500 is available bringing the price after the credit down to $33,500. This is a high price for what is really a four passenger commuter car. So how does the energy situation compare to my current vehicle and to others I might consider?

In order to estimate potential savings some assumptions will need to be made regarding how often and for how far the ICE in the Volt would be used. So, I'll figure that I'll do my normal commute four days per week and that I'll plug the Volt in at the office (actually, down the street at the laboratory) during each of those days so that the ICE isn't used. On the fifth day, I'll assume I go to the office and then leave for a meeting 35 miles away, that is, 70 miles out and back from the office, and then another 32.5 back to the house. I'll also need to use the fact that the Volt is specified at 50 m.p.g. when the ICE is running the electric motor. I can, no doubt, do better than that but I'll use it.

Using these figures, I estimate that I spend $61.91 per week or $3,219.34 annually on gas in the Land Rover, and that I'd spend $22.94 per week or $1,193.04 annually for gas in the Prius, and $17.44 per week or $907.00 annually on gas plus electricity for the Volt.

Now, the Land Rover is paid for but not by me (except indirectly). The Company will get a minor cash infusion by selling it. I'd estimate that the Prius will cost about $7,000 less than the Volt after all is said and done (that is, purchase price out the door). The $286/year isn't going to make up that difference, so the rational thing to do is to buy a Prius, assuming that a pure ICE vehicle is ruled out. More to follow.

Saturday, September 04, 2010

A319 - the final chapter



I've discussed the accelerometer data I gathered on takeoff and landing in Airbus 319's, and I made some calculations with the data involving engine thrust and energy dissipated in braking. The final calculations I've made involve takeoff and landing rolls of the aircraft.

Excel makes it very easy to perform numerical integration of a time series of data such as that gathered by the Pasco Sparkvue software on my iPhone. The basic idea is that the sample rate was set at 20 Hz, so a data point was gathered every 0.05 seconds. I assume that acceleration is constant between samples, multiply the duration of 0.05 seconds and add it to the previous velocity to get the new velocity. Rinse and repeat. Do the same to integrate velocity to get distance.

On takeoff, initial speed is 0 and initial distance is 0. On landing, initial distance is 0 but initial speed is back-calculated by assuming a speed when braking stops. In my earlier posts, I assumed a speed at the end of brake application of 10 knots but that gave fairly unrealistic landing speeds and rolls. I adjusted to 15 knots which is acceptable by the A319 operating manual (max. taxi speed is 20 knots, 10 knots in turns). This gave a more believable touchdown speed and landing roll (though still, I suspect, too low and too short).

I calculated the distance from start of takeoff roll to rotation to be 4,350 feet and, as I mentioned in the earlier post, the rotation speed to be 152 knots. I find these numbers to be pretty credible. For landing, I calculated the touchdown speed to be 99 knots and the landing roll to be 2,800 feet. The latter two numbers are suspect, hopefully an A319 pilot will comment. Or, perhaps, I can install an A319 simulation in MS Flight Simulator and try it myself.

Saturday, August 28, 2010

The bracelet rage

Was I asleep? I don't even remember where I read the first article about some sort of bracelet designed to, in some fashion, harmonize your energy field or some such. I do remember, though, that it was just this past Wednesday!? This particular one was the Power Balance Bracelet. I read about it and sadly shook my head. Its makers claim to embed frequencies into a hologram that "resonate and respond to the natural energy field of the body."

Then,THE VERY NEXT DAY, I was talking to a person with whom I work and noticed an unusual looking bracelet on her wrist. Innocently, I asked her what it was and she mumbled something about "balance" and told me that she'd give me a card from the guy that sold it to her. Sure enough, she had an EFX BRACELET that uses a hologram that "contains algorithms and frequencies" that interact positively with your body's energy field at the cellular level. As someone commenting on a site said, "how could that not work?"

Next, my stepson asked me to email his Spanish teacher, holding a note out for me to read. "Why, what's that bracelet you're wearing?" I asked, knowing the answer. Andre doesn't know the name of it but it's all the rage on his football team. I shook my head and told him it's useless. "No," he said, "they proved it works." See below.

Now I'm watching ESPN and see a series of advertisements for the iRenew Bracelet with its "Biofield Technology." And they have a quantum physicist! You can't go wrong if you're dealing with energy and have a quantum physicist on your side.

All three show the same "tests" to demonstrate the efficacy of the bracelets. There's one where the victim mark subject holds their arms out to their side and lifts a leg. The grifter tester pushes down on the arm sticking out to the side with the raised leg at about bicep level, first without (always) and next with (always) the bracelet. Due to learning, the mark subject will do better at resisting the second time and the snake oil salesperson vendor will state that it's due to the curative powers of the bracelet.

There's another where it's purported to enable a person to rotate farther from front to rear at the waist as measured by an arm extended out foreward. As usual, the "with the bracelet" test is second. You can go to any of the linked sites and see videos of these "tests" in action.

Back in the 1970s there was a pyramid craze. People wore wire pyramids on their heads to increase their intelligence or sleep better. I remember being offered ... an illegal substance commonly rolled into cigarette shaped cylinders and smoked ... with the kicker that "it was cured under a pyramid." People go to Sedona, Arizona for a "harmonic convergence" and then buy crystals. This sort of woo has always been around I guess, the new aspect is the word salad involving words like quantum, biofield, resonance, hologram, algorithm, and cellular.

Two of the three companies above offer to donate part of the price of some of their items to charitable causes - Save the Seas and Ovarian Cancer. I guess that's a good thing, in the way that you'd want the guy that mugs you to donate some of the proceeds to Jerry's Kids. The sites talk about scientific studies and evidence but I can't see anything except testimonials.

The placebo effect is well known and I'm all for it but the gullibility shown by the ability to make a living selling these pieces of plastic for $30 is another sign of the descent into the abyss of the level of scientific literacy of the average American. In the Far East some believe Rhino horn or shark fin or some other animal part will give them virility or cure them. We smile condescendingly and "tsk tsk" and send our money off for pieces of plastic with holograms embedded with frequencies to tune our biofields.

Update: Rhett Allain at Dot Physics has a supplementary and probably better explanation for the success of the first test described above in his post here.

Thursday, August 26, 2010

A brief essay on logic

While driving, I typically listen to Sirius Satellite Radio dividing my time between BBC World Service and Radio Classics (a channel devoted to the old time radio dramas and comedies). BBC is advertisement free (excepting adverts for its own programs of course) but Radio Classics has advertising for various things, including other channels, on the half-hour. One of the channels advertised is BB King's Bluesville.

During the commercial, BB King comes on and says (as close to verbatim as I can remember) "I'm the mayor. And if BB King doesn't like it, I figure no one else will either." Huh. This is, in first order predicate logic, known as an implication, i.e., if A then B, or A->B (pronounced "A implies B"). This implication is, as the saying goes (and as can be shown in a truth table), logically equivalent to | B -> | A (man, I wish I had more symbols in the Blogger interface: -> is an implication arrow; | is negation or "not" so that | B -> |A should be read "not B implies not A").

To BB's statement, this translates to "if not 'no one else will like it then not BB King doesn't like it.'" Next, "not no one else will like it" translates to "there exists someone who will like it." And "not BB King doesn't like it" translates to "BB King likes it." Thus, BB's statement is the logical equivalent of "if there exists someone who will like it then BB King likes it." There probably is no music such that there does not exist someone who will like it. Thus, there is probably no music that BB King does not like.

I'm guessing that that's not what he meant.

Monday, August 23, 2010

More on the Airbus A319 data

In my previous post I discussed gathering some data from the Airbus A319. I want to look into this a bit more, and consider some of the forces involved. Starting with takeoff and looking here I find that the standard maximum takeoff weight of the aircraft is 64,000 kilograms and that its range at that takeoff weight is 3391 kilometers. There are several variants of the aircraft but I'll assume that the figures cited are correct. There were no empty seats on the plane but Wolfram Alpha tells me that the distance from New York Laguardia to Chicago O'hare is 1180 kilometers so I assume that a partial fuel load was carried. The maximum fuel capacity was found here to be 24,210 liters or 24.21 m^3, which, at  804 kg/m^3, has a mass of 19,465 kg. I'm going to speculate that the aircraft carried 2/3 of its maximum fuel capacity, which should meet FAA regulations and United's standard operating procedures, for a weight savings of 6,488 kilograms.

So we're contemplating an aircraft with a mass of about 57,512 kg. and an average "mid roll" acceleration of about 3.4 m/s^2 by my data. So, as usual F=m*a, and the force the engines are applying is 195,500 Nt or about 44,000 pounds of force. This is, for the two engine aircraft, 22,000 pounds per engine. I've checked various sites and determined that the specific aircraft was likely the A319-131 model with IAE 2500 series engines with thrust rated in the 25,000 pound force range. Thus, the data is clearly on the right track. I do so love it when that happens.

 How about stopping? The aircraft from Chicago O'hare to John Wayne Airport in Orange County was also an Airbus A319, presumably another "dash 131" as they say in aviation. Since it was also full and traveled a considerably larger distance, I'll assume that it started at 64,000 kilograms. Here I find that my flight took 3 hours, 42 minutes, or 3.7 hours. I find here that, as an estimate, the A319 burns maybe 5,000 pounds mass or about 2,270 kilograms of fuel per hour so I estimate that the aircraft burned 3.7*2,270 kilograms from its 64,000 starting weight to land weighing 55,600 kilograms.

Touching down at 90 knots (I suspect this is actually a bit slow) or 46.3 m/s, the airplane has a kinetic energy of 0.5*55600*46.4^2 or 59,850,000 joules. It stops braking at 10 knots or 5.14 m/s and then has about 734,000 joules of kinetic energy (non-intuitively, not that far from my Land Rover LR3 HSE at 55 m.p.h.). The brakes have dissipated (that is, turned into heat) about 59,000,000 joules in about 27 seconds. This equates to a rate of energy dissipation of 59,000,000/27 or 2.19 megawatts. They are actually assisted in this disspation by burning jet fuel in a process called "reverse thrust" but in the end, that's the kinetic energy that is dissipated. Of course, braking is an extraordinarily efficient process for turning kinetic into thermal energy, slowing the plane down by reverse thrust is much less efficient but, in the end, it's all turned into dispersed thermal energy.

Next post: Integrate again for length of takeoff and landing roll.

Sunday, August 22, 2010

Airbus A319 on the runway

Like most modern "smart phones," the Apple iPhone has accelerometers on all three of its axes so that it knows its orientation. This enables the screen to flip, games involving motion to be played, etc. Various companies have produced apps to enable the user to have access to the acceleration data gathered by the accelerometers, I've posted about playing with that feature before.

Of course many have pushed this capability farther than I have, but Rhett Alain at his Dot Physics blog reviewed some of these apps and did a brief review of the Pasco Sparkvue app. Pasco is a company that makes various sensors that are typically used in Physics classes. The Sparkvue app is made to allow the use of their sensors with the iPhone, but includes access to the iPhone accelerometers. I purchased this app, and will likely also purchase some of the sensors as well.

I was in New York City (Queens, actually) for a conference held by the American Society for Nondestructive Testing, ASNT. By a freak accident (the flight crew is quite adamant that such things must not happen), on takeoff from Laguardia Airport, I happened to have left the iPhone on (in airplane mode) and Sparkvue running with the y axis very close to parallel to the longitudinal axis of the airplane, recording data. Shockingly, the same thing happened upon landing at John Wayne Airport in Orange County. I have GOT to be more careful about this.

But, having gathered the data anyway, I thought I'd spend a few minutes playing with it. The Sparkvue software enables adjustment of units ("g's" or meters/second^2) and sampling rate. I used meters/second and 20 Hz. I've inserted graphs of the speeds determined by numerically integrating the acceleration data below, I cut off the takeoff data at about 30.3 seconds because that's when the aircraft "rotated" (lifted the nose wheel off the runway, that is, began to leave the runway) and I didn't account for the fact that the downward acceleration of gravity now had a component along the y-axis of the iPhone, giving a falsely high reading of acceleration (the Equivalence Principle).

I intend to go back and attempt to correct this by estimating the so-called "deck angle" (the angle between the aircraft's longitudinal axis and horizontal) and backing it out of the numbers. This will enable me to estimate the aircraft's acceleration once airborne.

For landing, I did approximately the same thing, but I wanted to know the touchdown speed of the aircraft. Data was recorded until the aircraft was at its taxi speed and turning off the runway. I estimated this to be 10 knots and used the "goal seek" facility of Excel to determine what starting speed would give 10 knots when acceleration was deemed to have reached zero.

I have no idea how accurate the accelerometers are in an iPhone, but the numbers calculated are within the realm of plausibility. I estimated Vr (rotation speed in pilot speak) to be about 152 knots, and touchdown speed to be about 90 knots. A knot is a nautical mile (6080 feet) per hour or about 1.15 statute miles per hour. The graphs are below:





Sunday, August 15, 2010

YouTube - A Turing Machine - Busy Beaver 4-state

The busy beaver function is, as far as I know (and I've looked around a bit), the fastest growing function currently known. I first learned about it here. I'd known of Turing machines from general reading but have never taken a formal course in computer science (sadly). But Mike Davey has built a Turing machine and used it to demonstrate a four state busy beaver.

If you want to know more about the busy beaver function and why it's interesting, a good place to start is at the link above.

YouTube - A Turing Machine - Busy Beaver 4-state

Science Digestive: My application for a job as a Homeopath

More fun poked at homeopathy. I admit that it's a soft target.

Science Digestive: My application for a job as a Homeopath

Sunday, August 08, 2010

Creationism Lives - The Daily Dish | By Andrew Sullivan

I'm a regular at Dr. Michael Tobis' blog Only In It For The Gold (his blog's name is a sarcastic reference to the meme that climate scientists are engaged in a conspiracy to promote climate change in order to get rich from grant money). Michael has a "mt's shared items" section where he links to articles that he finds interesting. Often, he'll link to Andrew Sullivan's blog from the Atlantic Magazine (a magazine I really enjoy) entitled "The Daily Dish." He's currently linking to the article Creationism Lives - The Daily Dish | By Andrew Sullivan which quotes portions of a Scientific American article bemoaning the level of scientific ignorance in the United States. And apparently, the origin is the National Science Foundation's bienniel reportScience and Engineering Indicators. It reports the results of surveys in various countries that indicate many Americans don't believe, for example, in evolutionary theory.

By and large, I agree with Sullivan's point here, but the article he cites (and his quotation of it ends with) includes the following: "
Only 33 percent of Americans agreed that “the universe began with a big explosion.” Hmmm.... if someone phoned me and said "I'm taking a survey, do you agree that the universe began with a big explosion?" I would say "no." If they asked if I agreed that what is commonly known as the "Big Bang Theory" is currently the most likely explanation for the origin of our universe, I would say yes. The Big Bang, as presently understood, was not in any way an explosion. So, would I be marked down as another example of American scientific illiteracy?

I believe that whoever published the information quoted by Sullivan was attempting to further the case that Americans don't understand science. Paraphrasing A. Conan Doyle through Sherlock Holmes, the writer had not the gift of the true journalist, the knowledge of when to stop. The author succeeded only in showing the limits of his or her understanding of science, or at least of cosmology.

CO2 Now | CO2 Home

I've seen widgets on various web sites that track atmospheric CO2 and, in glancing at one, something caught my eye. I determined to visit the source site, called CO2 Now | CO2 Home to verify that what I'd noticed was accurate. Here's the image I looked at:

Now, what disturbed me is that the year over year increase was about 72% larger in the July, 2009 to July 2010 period (0.606%) than in the July, 2008 to July 2009 period (0.352%). This is quite disturbing in that the July 2009 to July 2010 period is one of subdued economic activity in much of the so-called developed world (to be fair, much of the previous period could also be described in this way).

Here's a brief graph of world GDP from 2005 to mid - 2010:

(Source: http://www.economicswebinstitute.org/ecdata.htm and http://web.worldbank.org/WBSITE/EXTERNAL/EXTDEC/EXTDECPROSPECTS/EXTGBLPROSPECTSAPRIL/0,,contentMDK:20370107~menuPK:659160~pagePK:2470434~piPK:4977459~theSitePK:659149,00.html)
Note that while world GDP declined for the first period noted in the CO2 concentration above and rose at about 3.3% for the second, the dip in GDP is not mirrored by a reduction in slope of the graph of atmospheric CO2 concentration for the period. I don't know whether the absence of a decrease in rate of growth of CO2 concentration is due to a statistical fluke, measurement error, volcanic eruption, or the increased use of coal to provide primary energy in emerging economies - China and India in particular. But an increased growth rate of atmospheric CO2 concentration without an increase in the rate of growth of economic activity is a disturbing data point.

Monday, July 19, 2010

Moldova??

I'd always just used Google Analytics to check my meager traffic flow, not noticing the "Stats" tab on my Blogger dashboard. I've been looking that over and it's pretty cool. But, amazingly, when I look at the "Audience" tab, for last week the country with the second largest number of pageviews on my blog was Moldova. That's right: USA; Moldova; Canada. On the all time list, Moldova is in sixth place behind: USA; Canada; Germany; Philippines; and Japan. What am I saying that's of keen interest to Moldovans? Please chime in!

Sunday, July 04, 2010

Subsidies, no, no subsidies...

One of the criticisms I read consistently of governmental encouragement of renewable energy (feed in tariffs, renewable portfolio standards, tax incentives, etc.) is that this artificially distorts markets, thereby leading to inefficiencies. "Let the free market decide" is the cry from the Competitive Enterprise Institute, the American Petroleum Institute, etc.

So it strikes me as ludicrous and ironic to read the extent to which the oil industry relies on subsidies, and to read the rationalizations provided for it. I've mentioned many times that I'm philosophically inclined toward market-based policies but that I believe they'll be insufficient to get us through times of diminishing primary energy supplies at increasing prices and sporadic availability, together with climatic effects of burning fossil fuels with very large inertia with respect to delays between emissions changes and effects.

So what we seem to have here is proposing that technologies that could help with our energy and climate dilemmas fend for themselves while those that contribute most to the variety of problems receive massive subsidies. Can anyone call this sane? There is absolutely no question that we need, and will continue to need, fossil fuels in massive quantities far into the future. They are intrinsic to much more than the generation of electrical energy and liquid fuels for transportation. But converging events make weaning ourselves from those areas where it's possible on a generational time scale critical. Because corporations' only responsibility is to maximize shareholder value, and shareholders value reliable short term returns above all else whereas the needed developments are quite long term, market intervention will, I'm sorry to say, be necessary.

Thursday, June 24, 2010

The "TRANS" system

I've run across a remarkable set of articles by an individual named Carl Johnson, who is beyond all doubt a lateral thinker. He has a high degree of mathematical and physical sophistication and the spectrum of issues he's contemplated is quite broad. He has a large set of articles on global warming, whose overall thrust is that "we're doomed," i.e., that the situation is dramatically worse than the worst case scenarios of the IPCC and the estimates of mainstream climatologists. I'm not going to go into those, but a starting point for those who'd like to is here.

But I'd like to look at an innovative transportation system Mr. Johnson designed in 1990, called the TRANS System. It involves "pods" in pneumatic tubes travelling cross country at 200 m.p.h., and locally at 60 m.p.h. and 30 m.p.h. The idea is to turn the "drag" concept upside down, the pod being propelled through concrete tubes by the drag force of air being pumped by at 230 m.p.h. Johnson also envisions elimination of wheel drag by lift provided by the Bernoulli effect. He ultimately envisions a system wherein people and goods can be transported to within two blocks of 98% of possible destinations in the U.S. at prices about 20% of today's and costs of 10% (the difference being used for reduction of the national debt).
There's no math in the linked page, though not because Mr. Johnson doesn't have abilities in that discipline - he's a graduate from the University of Chicago in "nuclear physics." There's lots of claims about the price to move a pound of freight or a pound of passengers. But there's no explanation of how those figures were derived. Beyond capital costs, of course (which Johnson also estimates), the primary operating expense would seem to be keeping hundreds of thousands of miles of air moving at 230 m.p.h. There are also costs associated with the various control systems he envisions.

While the state of research on such systems is not highly active, it's also not non-existent. A brief article with further references of the use of so-called "PCP" (pneumatic capsule pipeline) systems for freight transportation by Dr. Henry Liu of the International Freight Pipeline Society can be found here. It's clear from reading this article and others that Johnson's system represents a large jump in sophistication, particularly with respect to the velocities involved (over 100 meters/second vs. approximately 20 meters/second). Johnson also discusses a  "linefill ratio" (the proportion of the tube occupied by freight or passengers) of 50% where the state of the art using blowers is about 3% and the hope is to use linear induction motors to increase this to 15%. There is also an extensive article on utilization of a PCP system for freight transport in New York City here.

Let's think about the power involved in such a system. We'll ignore any change in potential energy required for elevation change. Using the D'Arcy-Weisbach equation and estimating things like the surface roughness of the inner surface of Johnson's concrete tube (he suggests a teflon lining and believes that, even with a Reynolds number on the order of 1.7*10^6, laminar flow can be maintained) and the operating pressure of the system, I can calculate a pressure drop of about 21.8. Pascals/meter. This is a loss of one atmosphere every approximately 4.6 kilometers. So, ignoring the mass of the cars (not particularly accurate since, according to Johnson's design, at peak capacity they might occupy on the order of one half the volume of a tube) we need enough power to provide a pressure boost of 21.8 Pascals in a distance of one meter and a diameter of two meters, or a volume of 3.14 m^3. This should be an amount of work of 21.8*3.14 or 68.5 joules. At 230 miles per hour, it needs to do this in 0.097 seconds. So the power required for that meter is 68.5 joules/.097 seconds, or about 704 watts.

Running some quick numbers for drag, lifting and moving the capsules would require another 440 watts for a subtotal of 1144 watts. Then, assuming a 3 meter long capsule with a mass of, say, 250 kilograms, accelerating it to 89.4 meters/second in maybe 30 seconds will take about 745 newtons. It will take 1340 meters to get to speed, so the power used in accelerating is 745 newtons*1340 meters/30 seconds or 33.3 kilowatts. Just as a rough estimate, in 100 kilometers, maybe 150 such accelerations are taking place, so the system must provide 150 capsules*33,300 kilowatts/100,000 meters or 50 watts/meter. Thus, the total estimated power required is, in round numbers, 1200 watts/meter. The energy requirements are starting to look "scary big." Does this level of power usage make any intuitive sense? Well, I have a vacuum cleaner that uses 11 amps at 110 volts for a power of 1210 watts. The vacuum cleaner is simply moving air, albeit turbulent even at much lower Reynolds number but through a much smaller area and over a shorter distance.

In any case, if I'm even close, a 100 kilometer tube would use 120 megawatts. Assuming that it's half full of capsules, and each capsule is 3 meters long, there are 16,600 capsules. Comparing this to cars, let's assume that 16,600 cars are moving at 55 m.p.h. and getting 25 m.p.g. These cars would use 10.1 gallons/second, each gallon containing 120*10^6 joules or 1.22*10^9 joules/second or watts. This is 1.22 gigawatts or 10.2 times as much power as the Trans system.

Now, there are many, MANY considerations beyond these factors. For example, no accounting of the primary energy (well to wheel for the cars, primary source to generator to fans for the Trans system) was done. And the system would use the energy to move the air regardless of whether there was a single capsule or the tube was filled to capacity whereas cars only use fuel when in use. But let's assume only 10% capacity utilization. The cars would still use about as much energy as the pods, and the pods would be almost four times as fast. Mr. Johnson may have a good idea from an energetic point of view. I wonder, though, how people would take to being in a fully enclosed capsule in a sealed tube?

*Edited to correct factor of 10 error. The advantage of the TRANS system is diminished considerably by this correction and likely constrained to be used in areas where high load factors are expected to be the norm.

Saturday, May 29, 2010

A telling symptom of crackpottery

The anti-science cult has quite a few sub-cults: anti-vaccination; creation science and anti-evolution; 9/11 truthers; homeopathy supporters; climate change skeptics, etc. I have a secret fascination for reading such nonsense. This has been a guilty pleasure for me for quite a while - I also am drawn to watch, in fascinated horror, such as Benny HinnRobert Tilton (for a different take on Tilton, see here), and other "spiritual healers."

In perusing the web sites devoted to such belief systems (I say belief systems as opposed to bodies of knowledge) there's often an element of paranoia - "there's a huge, malign conspiracy to quash the truth, a truth to which I and those of like belief have access." One way this frequently expresses itself is in the demand for debate. See the comment at 10:16 on May 29, 2010 here, the touting of a debate at the Oxford Union here or the report of an "evolution debate" here for examples.

Why is this? Are questions of science, nature, and fact settled by debate? Obviously not. I actually participated in debate in High School and was coached in the skills necessary to prevail in a formal debate on such topics as: Resolved: Taxpayer funds should be used to flouridate Rockford, Illinois' drinking water. Of course, I'd need to be fully prepared to argue the affirmative or the negative side. It involved gathering facts that support either argument and being prepared to defend against such arguments gathered by the opposing side. The judging was quite formal and a winner was always declared.

This is what the supporters of creationism, anti-vax, homeopathy, etc. want - the ability to utilize clever tactics to convince an audience lacking in specialist knowledge for the purpose of persuading the greater public and thereby influencing public policy. But debating skills (at least insofar as convincing a non-expert audience on scientific topics) do not equate with the ability to ferret out the truth from disparate data. Either skill takes dedication and perseverance to develop; scientists choose the latter and thus may fall very short on the former.

Thus, when looking at blogs and web sites with viewpoints on subjects on which I'm not an expert (and no one really has a blog or web site arguing the arcana of the physics of acoustic propagation in steel or the acceptable level of heat input in a flux core weld), if I see a lot of clamoring for debate or the citation of the results of debate, I become immediately skeptical of the viewpoint being espoused.

Monday, May 03, 2010

A dip into the strident atheist, liberal pool

I read several of the blogs at the blog host ScienceBlogs. In fact several are on my blog roll. One that I don't link is Pharyngula. I've mentioned in a previous post the frustrations I've had commenting there. PZ Myers, the publisher (owner?) of the blog posted a cartoon lambasting libertarians (it was, IMHO, on point to an extent) and asking if they have a sense of humor. The self-righteous, holier than thou (but in a Godless way) chest thumping began immediately.

Now, I have libertarian leanings, though I well recognize the shortcomings of the doctrinaire libertarian agenda, particularly on a finite planet where we're going through all resources like an alcoholic goes through a bottle of gin (not speaking hypothetically here). But, being a glutton for punishment and suffering from SIWOTI syndrome, I waded in. The model of Pharyngula is as follows: PZ Myers writes on a subject of derision (typically involving one of a few subject areas such as intelligent design, theism, Catholicism in particular, etc.) and then the participants pile on and deride. It's almost competitive.

I didn't support the libertarian position per se but I pointed out that, for such an enlightened congregation, they sure did seem like a bunch of (quoting myself here - see comment #216) insufferable, self-congratulatory windbags after screen name Azkyroth declared a characteristic of libertarians to be (comment #26) "insufferable smug self-righteousness" without a hint of irony. Well, of course a spiralling war of name-calling ensued with me using such words as sycophant, accusing them of tribal and herd-like behavior, and mentioning that they had a devotion to PZ that seemed like worship of a god (as an aside, to offer a counterexample to my assertion that they simply fall in line, Rutee, Shrieking Harpy of Dooooom, pointed out that there had been disagreement on whether video games are art). I actually forswore name-calling after a few rounds, though I did state on multiple more occasions that I felt they were pack-like. I do and they are.

For my trouble, I was called: arsehole, asshole, fuckwit, arrogant idiot, Asshole of the Road (that's pretty clever, huh?), a sad little man, snarky asshole, fuckwit of the road, a moronic fucking asshole, and a dicknosed clownshoed fuckburger (though there was an element of irony in this last - see comment #367). The "troll" and "tone troll" accusations were plentiful, but that's to be expected. Then, in comment #377, a_ray_in_dilbert_space offered the following (quoted in its entirety):

KOTR, Have you in fact observed interactions here at Pharyngula? I would call your attention to something you might have missed. To wit, the blog functions in an almost entirely unregulated manner. Comments are posted immediately. No pre-monitoring. No censorship. And yet, the signal to noise ratio is higher here than at most blogs where monitoring is much more heavy-handed.

Now ask yourself: How does that work? How is it that a blog on evolution, biology, atheism and liberal politics is not completely overrun by the much more numerous and vociferous Faux News crowd? When you understand that and understand the role "tone" plays in that process, you might understand the dynamics here a bit better.

I think his point is that the insult hurling and name calling directed at dissenters keeps the signal to noise ratio high by keeping the riff raff out. I don't frequent Faux News (the closest I come is an occasional bout of self-flagellation at Watts Up With That) but, by reputation, the denizens thereof do not shy from such battles. I leave it to readers to conclude whether a_ray's point is well-taken.

The misrepresentations of my comments, the tortured logic, and the failure to comprehend in the zeal to take me down were manifest, but too numerous to list. As an example, Kagehi, in comment #231, was bemoaning the fact that in Arizona, you can't challenge being fired unless you can show that you were fired because you're in a protected class (among many other complaints about the perceived lack of employee rights in Arizona).

I replied as follows: "So, a job is your right? Should you also be able to force another company to hire you? Should the government determine how many employees your employer has? Where they locate their facilities? When you get promoted? What furniture you have in your office? What else? When a fired employee sues and loses, will the government pay the company for its defense? Will they implement any sort of penalty for such suits being brought frivolously?" Multiple subsequent comments, despite my pointing out that it was incorrect, assumed that I'd implied that Kagehi stated that these things had happened. I implied no such thing, but Kagehi clearly wants at least one of them to happen as evidenced by his complaint in #341 that companies can "refuse you work for purely arbitrary reasons."

All in all, I learned from it. But SIWOTI syndrome is a disease that has flareups, so it's possible I'll go back there again.

Friday, April 30, 2010

The consequences of turning

In my post on Highway m.p.g. I recommended always travelling in such a way that your destination is at a lower elevation than your starting point. And in my post on headwinds I believe I showed conclusively that one should always travel with, rather than against, the wind. But to these, I'd like to add another recommendation: always travel in such a way so as to have no need to turn.

Turning a vehicle uses extra fuel in an obvious way, i.e., it increases the distance traveled. But it uses extra fuel in another way as well. As noted by Sir Isaac Newton, changing the momentum of an object requires a force - this is his famous "second law of motion," commonly summarized as "F=m*a." But momentum is a vector quantity (it has both magnitude and direction) so changing direction at a constant speed means momentum is changing. This requires a force which the road applies to the vehicle through the tires (in reaction to the tires applying this force to the road - Newton's third law of motion). This force must ultimately originate in the prime mover of the vehicle and, for internal combustion driven vehicles, must come from the burning of fossil fuels.

So how much fuel are we talking about here? I've calculated the forces involved in traveling in a straight and level line at 55 m.p.h. before, in my vehicle this takes a force of about 805 newtons. If I look at a circle with a circumference of 3.667 miles (this was chosen only to make it a four minute circle at 55 m.p.h.) and hence a radius of 939.2 meters (slightly less than a kilometer) then, utilizing the equation for centripetal force (F=m*(v^2/r)) I can determine that the force required to turn the vehicle is 1,777 newtons. This force must be developed in addition to the 805 newtons required to overcome aerodynamic drag and rolling resistance. Thus, driving in this particular circle more than triples the amount of force required at 55 m.p.h. and hence more than  triples the fuel used to travel any given distance in this manner.

Now, obviously, unless you have a number and a bunch of corporate logos on your car, you won't be driving continuously in a circle but this does illustrate the effect of having to apply the force required to make the car turn. Thus Rob's rules of fuel efficient driving are as follows:
  1. Travel downhill only
  2. Travel downwind only
  3. Do not turn
Follow these three simple rules and I promise you dramatically improved gas mileage!

Update: DON'T LET THIS HAPPEN TO YOU! In my rush to get a post done in April, I made the simplest of freshman physics errors. Thanks to Ed Davies (see comments) for causing me to give it enough thought to see the error.  There's no question about the centripetal force, however, no energy is added to the car. This makes sense - its mass doesn't change (reduces slightly, actually, as fuel is burned); it's speed doesn't change; and it doesn't change its position in a field. So both its kinetic and potential energy are constant. What gives? Well, energy is added by work being done on an object. It's true that the road exerts a force on my vehicle but that force is perpendicular to the instantaneous displacement of the vehicle at all times. The centripetal (road on car) force is directed to the center of the circular path, the displacement is tangential. Work is the product of force times displacement IN THE DIRECTION OF THE FORCE (defined as the vector dot product of the force and the displacement). Since there is never any displacement in the direction of the force, no work is done on the vehicle and thus no energy is added and the engine needn't do any more work.

As to my comment about the airplane, it stays at a constant altitude and slows down, thus its energy is reduced. So, does that mean that it's doing work on its environment? It does, reflected in the motion of the air displaced.

The rules will still work - a straight path is the shortest so you'll use less fuel by always travelling in a straight line. But your miles per gallon won't go up. And I could quibble by saying that taking turns deforms the tires and point out the hysteresis losses in going into and out of turns. But really, I just goofed.

How does one blush online?

Wednesday, April 14, 2010

Not to pooh pooh NASA, MIT, et al, but...

In my blog list is a link to a site entitled "Altternative Energy. It's an interesting site and frequently has items well worth reading and other times more silly or trivial. But today I saw an article about an aircraft called the "Puffin. This is a concept aircraft designed by one Mark Moore, a NASA aerospace engineer. The article quotes briefly from and links to the NASA site about the Puffin.

It's a single person vehicle ostensibly capable of vertical take offs and landings and a top speed of 150 m.p.h. (thought it's stated that the Puffin is more efficient at lower speeds). It's 12 feet long with a wingspan of 14.5 feet. It's stated to weigh 300 pounds empty, with 100 pounds for batteries and 200 pounds of payload (pilot and baggage). It's electrically powered and its motors develop 60 horsepower. Its range "with current battery technology" is stated to be about 50 miles.

Well. First, it doesn't exist, even as a prototype. But Analytical Mechanics Associates has produced an animation that can be seen in a YouTube video. According to the video, a one third scale validation model was to have been tested in March for hover capability, with transition to forward flight demonstrated after that. I have been unable to determine if these test flights have actually taken place.

But what about the plausibility of such a craft? Let's start with battery capacity. I'm going to assume the Puffin will achieve its 50 mile range at 100 m.p.h. I'll also assume that the 60 horsepower are required to achieve the top speed of 150 m.p.h. Since power required varies generally with the cube of speed for forces, such as aerodynamic drag, that vary with the square of speed, I can roughly estimate that the Puffin will require 60/1.5^3 (1.5 is the ratio of 150 m.p.h. to 100 m.p.h.) or about 17.8 horsepower. I'll be generous to the claims and assume zero reserves of energy. Thus, the batteries must supply 17.8 horsepower for 30 minutes to go 50 miles at 100 m.p.h. Googling (17.8 horsepwer)*30 minutes in kilowatt hours returns the conversion to the 6.64 kilowatt hours that are required.

Moving on to this excellent battery site I find that Lithium-ion batteries have the highest energy density available currently at 128 watt-hours/kilogram. Thus, I'll need 6,640/128 or 51.9 kilograms of batteries. This mass weighs 114 pounds here on Earth. This 6,640 watt-hour battery pack will cost an estimated $28,000.

For fun, I ran through the same calculation at 50 m.p.h. (the stalling speed in forward flight is not indicated, nor are such aerodynamic characteristics as flat plate area, propeller efficiency, lift/drag ratios at various speeds, etc.) and determined that, with no energy to spare the batteries must store 1,660 watt-hours of energy weighing 28.6 pounds and costing $7,090. But this battery pack could only maintain 150 m.p.h. for a little over two minutes.

OK, let's finally figure a 100 pound Li-ion battery pack. This 45.4 kilogram pack should provide about 5,810 watt hours. That capacity will provide 60 horsepower for just slightly under eight minutes. And remember, this is to "dry tanks" and includes no increment for such things as vertical takeoff and transition to level flight (very energy intensive phases for aerial vehicles with which I'm familiar). Finally, let's realistically assume that it would be nice to have a 10% reserve. How fast can you fly to have a 50 mile range with the 100 pound battery pack and have such a reserve? It's kind of a nitpicky problem in algebra and units, but the answer is about 89 m.p.h.

So my conclusion is that, while the claims may not actually be false, they seem quite misleading. You may be able to go 50 miles (and glide, powerless, to a landing); you may be able to go 150 m.p.h.; you may be able to take off vertically with a payload of 200 pounds; but you won't be able to load up 200 pounds, take off vertically, and fly 50 miles at 150 m.p.h. to your destination.

Sunday, April 04, 2010

PA32R-301T

That's the model number of my Piper Saratoga, a 1981 model. Now, I know what you're thinking (at least if you haven't followed my blog for long and maybe even if you have). What's a guy who writes about energy savings, fuel efficiency, and peak oil doing in a private airplane?

The answer is that I've wanted to fly since being a small child and  thus I acquired my Airman Certificate ("pilot's license") in 1981. In 2001, well before I began to concern myself with energy related matters, I acquired the airplane. I've been all over the country in it, and have flown it for around 500 hours.

As transportation security measures have increased, the attractiveness of driving to the hangar, performing the preflight inspection, taxiing out and flying to the airport nearest my destination (as opposed to an air carrier airport) becomes more and more attractive. This increases the range I'm willing to fly myself. There are drawbacks as well: I don't have the weather capabilities of the airlines; outside of about 650 (nautical or 748 statute) miles I'll need to stop for fuel; adverse winds have a huge effect on ground speed; and it's quite costly. For very long distances, the airlines are significantly faster though with the hub and spoke system, one hour early arrivals, waiting for baggage, and other delays, the distance at which airlines become faster door to door is longer than one might think. Also, for business meetings, having my transportation ready when I am means that I don't have to leave early to catch my flight.

Parsing the model number, PA stands for Piper Aircraft, it's the 32 series (no significance to that), R indicates that its landing gear is retractable (chicks don't dig fixed gear), 301 is the maximum continuous horsepower of the Lycoming TIO540-S1AD engine (actually, it's one more for some obscure reason), and T indicates turbocharging. As to the engine, T is turbocharged, I is injected, O is (horizontally) opposed (cylinders), 540 cubic inches is the displacement. It's a "dash S1AD" variant, the nomenclature has no obvious significance.

So I have a turbocharged aircraft capable of developing about 300 horsepower. This power is only used on takeoff and initial climb, typical cruise power is about 70% of this number or about 210 horsepower. Just for fun, if I assume that the engine efficiency at this power setting is 25% and that there are about 125*10^6 joules in a gallon of avgas, my airplane should burn 18.04 gallons/hour. I actually run at a flow of about 18 gallons/hour as shown on my fuel flow meter (pilots, obviously continuously concerned with fuel, think in terms of pounds or gallons per hour). As I've repeatedly stated, I just love it when calculations and data or two methods of calculation agree.

These 18 gallons at 13,000 feet will typically take me about 168 nautical miles or 193 statue miles (the "knot" is one nautical mile or 6080 feet per hour). So, in terrestrial terms, I get 193/18 or 10.7 m.p.g. Not really so good. The Saratoga is known as a bit of a sky-borne SUV, it has six seats and three baggage areas. It's a little draggy and a bit heavy in comparison to piston single engine airplanes.

For a given amount of shaft power, the airspeed achieved (at any particular "density altitude") is controlled by propeller efficiency and total drag. I can increase my range and consequently my "specific range" (miles per gallon) by flying at slower airspeeds. At about 140 knots (a bit over 160 m.p.h) I can reduce the fuel flow to around 10 gallons/hour. This works out to 16 m.p.g., more along the lines of what you might expect for a fuel thirsty road vehicle.

But one of the main reasons people buy airplanes is to go fast, and so I rarely use this method. It can, however, result in a quicker trip if the extended range results in the elimination of a fuel stop. Such a stop typically adds about 45 minutes to a trip. But really, by the time I've been in the plane over five hours, I'm ready for a stop.

Finally, if I put passengers in three of the five seats remaining (more than that results in the need to fly with partial fuel loads, thus reducing range) I can achieve a reasonable figure for "passenger miles per gallon" of 42.8. To be candid, that rarely happens though. No amount of mental gymnastics can make N8409Y a fuel efficient way to travel.

Wednesday, March 31, 2010

A man whose self-love knows no bounds

My greatest daily number of hits ever came subsequent to my Psychologist in the house post. The visitors came primarily from Marc Morano's "Climate Depot" site. He's a "denialist" (from the mainstream climatology side) or a "skeptic" (from those who disagree with mainstream climatology on anthropogenic global warming) whose specialty seems to be torpedoing what he perceives to be the liberal dogma. Among other accomplishments, he spearheaded the Swift Boat attack on Presidential candidate John Kerry in 2004.

There's no question that he's a superb ex tempore debater and an effective advocate for the Alfred E. Neuman position on anthropogenic global warming. His site claims to be a clearinghouse for news on climate science and policy, but it had best be a certain kind of news.

But if there's one thing Morano loves more than s _ _ _ stirring, it's Marc Morano. He's a veritable mother lode of self-citation. In order to keep track of his self-citation, I'm going to start logging the occurrences of "Morano" on his site. I'll periodically report, with raw data as well as trend analysis. Does anyone think I can get Steve McIntyre interested? In any event, yesterday's count was 24, today's is 26.

Update: Climate Depot's "Morano" count hovered in the mid '20s for a couple of weeks; but in the last couple of days has dropped to four. I wonder if he stopped by here?

Monday, March 29, 2010

Leasing the sun

There may be many such firms but I've been hearing radio commercials for a company called "Solar City." The business model is to provide rooftop photovoltaic systems at little or no initial cost. Solar City maintains ownership of the system and leases it to the home or business owner. The claim is that the total cost to the owner (lease payment plus paying for the much smaller amount of electricity used) is less than the electric bill prior to installing the system. They have a javascript application in which you install such information as your typical electric bill, your zip code (then followed by actually pointing to your house on a map), your roof slope and direction, and your electricity provider. It then returns a 15 year projection of savings, with a graphical representation of lease payments, electric bills, and the electric bills that would have been paid. There's an estimated rate of increase built in. The result of my initial inquiry looks like this:

Note that, at the outset, I can save $4.00/month. Not a lot. But I used my current electric energy usage. What if I significantly increase my usage by the purchase of a Nissan Leaf? In my post on the subject I estimated that I'd need to utilize about 17.5 kilowatt hours per day to charge the Leaf. Now, of course, I'd be charging it during the daytime rather than at night so the system would need to be sized for my use other than the Leaf plus the 17.5 kilowatt hours per day, a total I'd estimate at about 66 kilowatt hours per day. Though the javascript application doesn't allow one to play with such fine points as what can be run during the day and during the night and the system doesn't allow for storage, adding the Leaf makes a difference:

Ah, $7/month, now we're getting somewhere. Of course, the Leaf is also busily saving me money. Further, it's better to have $7/month than not to have it and I could save a few bucks more by replacing my wife's car with a Leaf. Or not.

Now, in principle, I've eliminated a large portion of my carbon footprint (moreso if I can coerce persuade my wife as well). If I could really do so, and if the solar system replaced 90% of of my household electricity and all of the energy use of mine and my wife's cars, using the information used in preparing this post and this post I can estimate that as much as 25% of my family's carbon footprint could be eliminated. This is well under the 95% that would appear to be required, but it's better than replacing incandescent bulbs with compact florescent bulbs. After appropriate due diligence, I may do so.

Sunday, March 21, 2010

Baseball: thirsty sport

I follow a few sports, chief among them are Major Leauge BaseballNFL Football, college football, and NHRA drag racing. I'm not a zealot and can't quote statistics as many can but I'm emotionally invested in the outcomes. But clearly, these sports and all others require the use of some form of fossil fuels; would their elimination make a big difference in our overall consumption? As I've mentioned, the "Fermi Problem approach" to such questions appeals to me. As it turns out though, it's a difficult problem, at least for me.

I've completed my Fermi analysis of three sports (Major League Baseball, college football, and NFL football). I did this at a very superficial level, only estimating the fuel used by the fans driving to the games and travel by the participating teams. Such a calculation involves estimating the answers to a myriad of data points, among others: how many games per season; how many fans at each game; how many fans in each vehicle attending the game; how far the average vehicle traveled to and from the game; what is the average fuel economy of the vehicle used; how far and by what means did the visiting team travel to the home team's venue; what is the fuel economy of the means utilized by the visiting team; and others. I didn't estimate the coal burned in field lighting, the natural gas used in heating the hot dogs and nacho cheese, the coal burned to power the HDTVs watched by fans not actually attending the game, and many others.

With those limitations in mind, the results of my speculation are as follows (in decreasing order of fuel used):
  • College Football: 9.0*10^6 barrels/year
  • Major League Baseball: 4.2*10^6 barrels/year
  • NFL Football: 1.0*10^6 barrels/year
I arbitrarily speculate that NBA basketball uses considerably less fuel than Major League Baseball not because an NBA team plays fewer games per season (since visiting teams in baseball typically play several consecutive games at each location) but rather because the venues are smaller and thus fewer fans travel to each game. Similar considerations apply to hockey. I think each of the major motor sports (NHRA, NASCAR, IRL) use much less still, because there is only a single event each active week, though it extends over multiple days. A similar consideration applies to golf.

In each of the sports I estimated, by far the largest fuel use was by fans traveling to the games. This use was typically an order of magnitude larger than that by team travel (anywhere from 8 to 40 times as large). And finally, the use by the three sports I estimated totals about 0.19% of our nation's annual oil consumption of about 7.5*10^9 barrels/year. Let's suppose that the sports I've looked at represent 10% of the oil consumed in all sports, then "sport" would be responsible for about 2% of U.S. oil consumption. I suspect this is high, since the fuel is consumed primarily by individuals and the "average person" I know likely doesn't use 2% of her oil consumption on sports. Thus, elimination of all spectator sporting activities is yet one more way not to get us out of our energy dilemma.

Sunday, February 21, 2010

34 Max?

Through a series of links, I wound up at a blog advocating mechanically (or electronically, I presume) limiting the maximum speed of passenger vehicles to 55 kilometers/hour (34 m.p.h.). Scott (the blog's publisher) lists the benefits, among others as: elimination of oil imports; reduction of CO2 emissions to below 1970's levels;
reduced loss of life and reduced injuries in motor vehicle accidents; reduced air pollution from exhaust; reduced particulates from tire wear; reduced energy in automobile manufacturing due to smaller and lighter components; reduced expenditure for infrastructure maintenance; increased motivation to use (now comparatively much faster) public transportation; and others.

He addresses many of the objections he anticipates as well, though I doubt that many who contemplate his suggestion will agree that he has adequately done so. He moderates his comments and states that a huge portion of the comments he's received consist only of name calling and doesn't publish them. In fact, there are very few comments published. I left several; time will tell if he publishes them.

And though a few of the comments I posted related to his erroneous use of "exponentially" and his stating that aerodynamic drag (as opposed to power required to overcome it) varies with the cube of speed (rather than the square), my main point of contention was that he makes broad claims (elimination of oil imports, reduction of CO2 emissions to pre-1970's levels) with no data or calculations to support them. This is something I try never to do, as claims without backup are plentiful on the 'tubes. I'm willing to be convinced, but he'll have to convince me.

Further, I am instinctively opposed to mandates and top down controls, so I suggested that the externalities of fast driving be paid for by those doing the driving, probably by a tax. With OBD-II on all modern cars, this could easily be accomplished at registration renewal time without big brother-like GPS tracking. The idea would be that people would be taxed on the extent to which they exceeded, on average, some speed and probably multiplied by the number of miles driven. I can already hear the howling!

But let me do his job and suppose such a thing was done. Would we eliminate oil imports? This needs to be a two part question because we'd use less energy to travel and use less energy to manufacture automobiles. For the first part, I'm going to assume that the adjustment has been made and that enough of the new variety of cars optimized for such a maximum speed are on the road to use them as the de facto standard. In the real world, that will take a while but let's see where it leads us.

We used (in 2005) 320,500,000 gallons of gasoline per day at  17.2 m.p.g.  I made liberal (but not completely unrealistic) assumptions on vehicle characteristics of weight, drag coefficient, rolling resistance, and area and calculated in the usual way - details can be provided if requested- and determined that we'd be able to get vehicles achieving about 134 m.p.g. after this rule is implemented and the situation stabilizes as described. At that rate, we'd save about 87.2% of the gasoline we now use, or 279,000,000 gallons per day. Now, we get about 19.5 gallons out of a barrel of oil, so we'd save about 14.3 million barrels per day. This is, in fact, more than we import so Scott is correct. This doesn't even include savings from reduced energy use in manufacturing lighter vehicles. I'll attack that, and CO2, in a subsequent post.

Who's in?

Saturday, February 20, 2010

The Nissan Leaf

I've posted a couple of times on supplying the necessary electrical energy to replace our passenger automobile fleet with electric vehicles, and I also discussed the Chevy Volt. An all-electric vehicle appears ready to enter the fray in late 2010 - the Nissan Leaf. While Nissan seems to be playing it close to the vest (the vehicle's weight and price as well as many other specifications are not given), between Nissan's site and Autoblog's site some conclusions can be reached.

Let's look at the combined aerodynamic and rolling resistance efficiency of the vehicle. The Leaf is claimed to deliver about 100 miles on a full charge, the lithium ion battery pack capacity is stated to be 24 kilowatt-hours or about 86.4 megajoules. The electric motor is less than 100% efficient in its use of the energy in its source. Based on this page and the 80 kilowatt (or 107 horsepower) motor in the Leaf I'll use 92% (the table shows the minimum as 91.7%). Also, the Leaf site discusses "0% to 100% charge" so I'm going to assume that the vehicle uses all 24 kilowatt-hours of energy in the battery pack to go 100 miles. Thus, the Leaf uses .92*24=22.1 kilowatt hours or 79.6 megajoules to go 100 miles.

How does this compare to "miles per gallon?" The 79.6 megajoules is the energy in about .66 gallons of gasoline, but the internal combustion engine is quite inefficient so I'll use 22%. Then we'd be considering a car that goes 100 miles on (0.66/0.22) or about 3 gallons. Thus, we're looking at a car whose efficiency in terms of aerodynamics and rolling resistance is about that of a gasoline burning car getting 33 m.p.g. Seems quite reasonable, though certainly not awe inspiring.

How about cost? I drive about 62 miles per day year around, so I'd use about 62/100 of a full charge, or about 14.9 kilowatt-hours from the battery pack. Let's assume the charging system is 85% efficient, so I need (14.9/.85) or 17.5 kilowatt-hours of electricity. This would probably be at a marginal rate of $0.17/kilowatt-hour since I'd invariably be over my baseline rate with the City of Anaheim. So I'd spend 17.5*0.17 or  $3.01 per day on energy to drive. This is, of course, $3.01/62 or $0.049/mile. Right now in my Land Rover LR3 HSE I'm spending about $0.14/mile on gasoline. The Leaf would provide considerable savings, amounting, in the course of a year, to about $2,060. Certainly, that's nothing at which to sneeze (grammatical pedant that I am).

As to performance, the Leaf boasts a torque (from a dead stop) of  280 Newton-meters (208 pound-feet) and a top speed of over 140 km/h (87 mph). It will accept a full charge from a compatible 220 volt system in about 8 hours, about twice that from a 110 volt circuit. At a suitable quick charge station, it will take an 80% charge in under half an hour and a boost good for about 35 miles in about 10 minutes. Such suitable stations are, at the moment, mostly a distant dream however.

What about creature comforts? It appears to be quite comfortable, modern, and light. It will have room for at least four adults, MP3 connections via USB, a proprietary system built into the satellite navigation system to indicate charging facilities within range, systems to allow one to receive emails from the car on their smart phone and to control certain functions (heating, cooling, etc.) remotely via that smart phone. All things considered, I'm going to look very closely at the vehicle when it becomes available.

Addendum: How much might I reduce my costs if I built a solar charging system to charge the vehicle's battery pack during my working hours? I went here to find the insolation available, using average insolation, the month of March, and a horizontal flat plate to see this map:
Conservatively, 4.5 kilowatt-hours/meter^2/day are available on average. If I'm fortunate, maybe I can create a collector of 2 meter^2. If I'm even more fortunate and technology smiles, perhaps I can find cells with 18% efficiency and provide circuitry to charge the vehicle. Thus, I'd get 2*4.5 kilowatt-hours*0.18 or about 1.6 kilowatt-hours. This would be enough to bring the vehicle from, say, 65% charged to 71.7% or to go a little less than an extra seven miles.  To bring it from fully discharged to fully charged would take a little under 15 days. I can do perhaps a little under twice as well in June but still, seemingly not worth the trouble and expense.

Tuesday, February 09, 2010

More reasons to be embarrassed to be called conservative

I am really not interested in having this become a political blog but, as mentioned in earlier posts, I want to be conservative. That is, I want to conserve our natural and cultural heritage, I want to conserve our resources, our civil liberties as enshrined in the Bill of Rights and elsewhere in the Constitution and its amendments, I want to conserve the rule of law, I want to conserve what's left of our nation's wealth.

So what am I to make of the descriptor "conservative" being used to characterize people who hold opinions such as those expressed by the participants in this clip? Here we see, as we saw with Bush, a celebration of intellectual laziness in the guise of condemning the "elite." We wouldn't think of such condemnation of elite athletes, but by God let no one more learned than Homer Simpson dare to govern us.

When one is expected to apologize for holding informed opinion based on study and inquiry and to celebrate a so-called "leader" who can't remember the list "energy, budget tax cuts, lift American spirits" it's about time to pack it in.

Friday, February 05, 2010

The Onion vs. The Science Channel

I've mentioned on several occasions my level of disappointment with the Discovery Network's lineup of channels and shows and the extent to which they have debased the original concept of bringing some level of scientific authenticity to the wasteland that is television. But a big hat tip to Michael at Only In It For The Gold for pointing me to the far superior Onion treatment.



Udate: So I'm watching "G Word " ("G" is for green, I suppose) on Planet Green (a Discovery Channel) and the host, Summer Rayne (think Johnny Rivers - "taps at my window"), is in Abilene, TX interviewing someone from AES Energy Systems at their Buffalo Gap wind energy facility. It's not really bad until Ned Hall, their President, says "this machine is 1.5 megawatts." Summer asks "and what does that mean?" Hall says "it's enough electricity for your home for the whole year." Ummm, an analogous inanity would be me saying "my car goes 125 miles per hour. That's enough to go from here to San Francisco." And this, let me repeat, is the President of an energy company.