Hydrogen Fuel Cell powered aircraft

Posted on April 7, 2008 by Lee Devlin

For the first time in history, Boeing demonstrated a manned, hydrogen fuel cell powered aircraft. I had written about a Sonex electric aircraft I saw at Oshkosh last year, albeit as a static display model that used 250 lbs of batteries. It would only operate for about 18 minutes at full power, or just a small fraction of the time you’d expect from a gasoline powered aircraft.

In this case, the flight was at a speed of 55 kts, at an altitude of 3300 feet for 20 minutes in a converted motor glider, so the range/capacity is likely to be on par with the Sonex. Boeing does not anticipate that hydrogen fuel cells will be able to provide primary power for a commercial aircraft.

I think that the outcome of these recent demonstrations show that the future of air travel will continue to depend on liquid hydrocarbon fuels. Short of a miraculous discovery, when fossil fuels are exhausted hydrocarbon fuels will need to come from biomass feedstocks. After a rash of articles inspired by a recent Science article critical of biofuels, even Time Magazine has jumped on the dogpile, parroting the statements that biofuels are a scam and an environmentally damaging approach to generating energy.

In the future, the sun and wind will likely provide enough energy to heat our homes and provide us with electricity. Those energy sources may even power a commuters vehicle a few dozen miles a day. But to move something like a ship, a truck, a train, or a plane, it appears we’ll be dependent on liquid hydrocarbon fuels for some time. This might not be the case if the energy density of battery technology would approach that of hydrocarbon fuels per kg., but thus far it’s still several orders of magnitude away. Even with the thermal to mechanical energy inefficiency of the internal combustion engine which averages around 30%, energy density is still the primary advantage of conventional fuels over batteries.

Perhaps the best chance to please everyone would be to use wind and solar power to pull carbon dioxide out of the atmosphere, combine it with hydrogen, and synthesize clean burning hydrocarbon fuels. I suspect that no sooner than a method became practical, there’d be another dogpile forming, no doubt protecting existing interests by decrying the evils of robbing CO2 from the atmosphere.

Renewable energy certainly has a lot of controversy and drama associated with it. You wouldn’t expect that from a field that should be primarily technical and scientific, but when anything has the potential to affect economics, politics, and the environment, technical arguments seem to hold little sway.

Ethanol’s Water Requirements

Posted on April 6, 2008 by Lee Devlin

My friend Peter asked if I would write about the amount of water it takes to produce a gallon of ethanol. I have often heard this figure to be quoted at 1000 gallons of water per gallon of ethanol. I wasn’t sure how accurate this was, so I started doing some investigation. I found that I live in a county in Colorado that has the most irrigated acres of any of Colorado’s 63 counties, accounting for 11% of the state’s total. I found that corn requires a moderate amount of irrigation as far as crops go, about 16.5 inches per year in my county. Alfalfa has the highest watering requirements or about 23 inches and melons only require about 8 inches annually. When you compare irrigation requirements with Colorado’s average rainfall of 15.5 inches per year, it is obvious that more than half of the corn’s water requirements must come from irrigation and this is even more apparent when you consider that corn only grows for 3 months out of the year and during those months, the rainfall total is only about 5 or 6 inches.

Some of the irrigation is provided through surface canals fed by mountain runoff and some is from center pivot irrigation which brings water up from deep wells. I will calculate the energy cost per acre of using a center pivot irrigator assuming a 200-foot deep well and a 50 psi pressure at the pivot’s center.

Since an acre is 43,560 sq ft. and we need to apply 16.5″ of water to it during the corn growing season, this comes out to 59,895 cu. ft. or 497,128 gallons of water per acre. Last year’s average Colorado irrigated corn yield was 189 bushels/acre and the average conversion rate is 2.7 gallons of ethanol per bushel of corn. So the ethanol yield per acre is 456 gallons. Dividing that into 497,128 shows that the number of gallons of water to produce a gallon of ethanol in Colorado is around 1100. This seems quite substantial. Colorado has a very dry climate where virtually no crops can grow without irrigation. In most of the corn belt states like Iowa and Illinois, the average rainfall is closer to 40 inches per year, and so irrigation shouldn’t be necessary and thus even though it may take just as much water to grow corn as it would in Colorado, the rain will fall whether you’re growing grass, or forest, or corn, so I don’t think that the amount of water consumption is as much of a concern as it is in states like Colorado where water is considered a scarce resource.

I mentioned I’d also do the energy calculation for lifting the water from a 200 foot well. 497,128 gallons of water weigh about 4.1 million lbs. and lifting that much water 200 feet and maintaining 50 psi at the center pivot would require 1300 M ft-lbs of energy. This is equivalent to 490 kWh. Derating for a pumping efficiency of 65% we can estimate it would require about 760 kWh in electricity consumption per acre at a cost of $76/acre using $.10/kWh for the electricity rate. With corn selling for around $4.60/bushel, this accounts for about 9% of the value of the corn. So spending $76/acre seems like a reasonable trade-off considering that without irrigation, the corn yield in Colorado would be close to nothing.

Water is the most renewable of all natural resources but sometimes it’s treated like it’s a scarce or even endangered resource. The stuff does literally fall from the sky. So I guess it all depends on one’s situation as to whether water is scarce or plentiful. If you are in the middle of a flood, water is anything but scarce, yet if you’re dying of thirst, it can be more precious than gold.

Is it worth 1000 gallons of water to produce 1 gallon of ethanol? Again it depends on one’s perspective. If you need to drive a car for 20 miles, 1000 gallons of water will be of no help, but a gallon of ethanol certainly would be. And in the majority of corn-growing states, not planting corn on the land will not prevent rain from falling on it so there’d be no real water savings.

How I became a Firefox/Thunderbird user

Posted on April 6, 2008 by Lee Devlin

I became a Firefox user about a year ago when Internet Explorer 7 started crashing every ten minutes on several of my computers. I looked all over the Internet and could not find a reason for the failure. When I encountered the message: “Internet Explorer has encountered a problem and must close.” The extra information, namely this:

AppName: iexplore.exe AppVer: 7.0.6000.16608 ModName: oleaut32.dll
ModVer: 5.1.2600.3266 Offset: 00065401

was of no use to helping me isolate the issue. I don’t know what I did that caused this to start occurring, but because IE is so tightly integrated into the XP operating system, I don’t know of a way to remove and reinstall it, or even if that could fix the problem. So I started using Firefox and found features in it that I liked and so now I use it exclusively.

I became a Thunderbird user the same way. About a week ago, my Outlook Express kept failing while trying to retrieve email from one of my POP accounts, giving me a cryptic error. I had confirmed that all the information and passwords were correct and after a few hours of fiddling with it, I made the problems go away by installing Thunderbird. Thunderbird took all of my email from Outlook Express and converted it over as well as my contacts list. Converting over my backlog of saved emails and contacts was what prevented me from getting off Outlook Express for so long. If I had realized how easy it would be with Thunderbird, I would have converted over a long time ago.

Replacing Remington and Norelco Shaver Batteries

Posted on April 6, 2008 by Lee Devlin

139

I came to the realization that I’ve never worn out a Norelco or Remington razor yet I’ve owned a number of them over the years. But I have worn out a number of shaver batteries. My first Norelco razor was a plug-in only model. I was lured into buying a battery-powered model that would let me shave without being tethered to the wall outlet. Over the course of a year or so, I noticed that the charge on the battery wasn’t lasting very long and so this eventually became no different than the model that had to be connected to the AC outlet all the time. I bought a replacement when I was planning a camping trip and would not have dependable access to an AC outlet. Over the course of a few years, this model did the same thing, i.e., its batteries wore out and it also had to be plugged in all the time.

At the time, I priced a service that would replace the batteries and figured out, like many others, I’m sure, that it wasn’t much more expensive to buy a new razor than to repair an old one. So I opted to get a Remington R9190 model that I could clean by running it under the water tap. What would they think of next? It had amazing capacity, providing 60 minutes of shaving on a single charge. However, after about 18 months, it too, needed to be left plugged in all the time.

I figured that these razors only needed new batteries, but knew that it would require getting the right kind of batteries, and then having to do some unsoldering and re-soldering. I found a website that sold shaver batteries and would provide the correct ones for the razors based on their model numbers. In this case, the razor model numbers I wanted to fix were a Norelco 6843XL and a Remington R9190. I found the battery packs at Electricshaver.com. In the case of the 6843XL, I received a single AA 600 mah NiCad battery with solder tabs at a cost of $9.95. The R9190 battery pack contained a pair of AA NiCads with solder tabs that were joined together at one end. I had to cut these apart to actually install them so it probably would have been better if they just provided two AA solder tab batteries. That battery pack cost $14.95. I realized afterwards that I could probably just have just ordered 3 regular solder tab AA NiCad batteries from any of a number of Internet sources for around $3.00 each and saved about $15. Live and learn.

The Norelco 6843XL came apart quite easily. I just removed two screws (although I did need to use a torx driver) and then popped its snap joints apart. The battery tabs of the single AA battery were soldered through the PC board, but with a solder sucker and some solder wick, they were easily removed and the battery was replaced.

The Norelco 6843XL was easy to take apart. It contained a single AA solder-tab battery.

The R9190 wasn’t as easy to disassemble. There were 4 exposed phillips head screws which I removed, but the casing still would not come apart. After a lot of time fiddling, I found that there were two more hidden screws under the rubber backing and once these were removed, everything came apart. It was first necessary to pry up the corners of the rubber backing which was glued down on the back of the shaver (as shown in the photo) to expose the hidden screws. I came close to giving up on it. It’s the reason you may have found this posting, because searching for ‘Remington R9100 R9190 R9200 shaver battery replacement’ came up with nothing on the Internet. So I figure that within a few weeks of posting this, it will start to get hits because if I’m having this problem, chances are pretty good that others are as well.

The R9190 had two hidden screws keeping it together. After prying up the rubber as shown in the photo, the screws were exposed.

The main reason I’m posting this is because I know how much I appreciate it when I find some obscure piece of information on the Internet that allows me to fix something that I’d otherwise have to throw away. I’m disappointed that Norelco and Remington continue to build products whose batteries cannot be easily serviced. I’ve read recently that many cellphones get replaced when their batteries goes bad after around 18 months of use. I find that to be extremely wasteful, and in the case of most cellphones, completely unnecessary because the batteries are generally easily replaced (unless you have an iPhone) . Of course, the battery packs sometimes have excessive markups on them when purchased from the manufacturer so that probably contributes to it as well.

I think that building batteries into a product in such a way that they cannot be replaced by an end user is unacceptable. Rechargeable batteries are only good for around 500 charge cycles and then they must be replaced. I wouldn’t want to be associated with a product where the batteries are so difficult to replace that the battery life determines the useful life of the product.

The R9190 has two AA NiCad batteries soldered together with some wiring. They are relatively easy to replace once you figure out how to get the case apart.

Both shavers are working great now and I can again enjoy the experience of untethered shaving.

UPDATE 2009-01-25

I continue to get a lot of hits on this web page so I can only imagine that many people have encountered the same problem, i.e., a razor that is still working, but with batteries that have gone flat. A very nice gentleman sent me the images below complete with annotations to show how he repaired his Remington Model 8100 razor. He replaced the solder tail AA batteries with holders for AAA batteries. Even though AAA batteries are much smaller, and usually have half the capacity of AA batteries, he found some that had nearly equal capacity to the AA batteries he replaced. The best part of his repair is that the next time they go flat, it will be very easy to replace them because it will require no soldering.

UPDATE 2012-02-26: I continue to have readers send me tips and photos on razors that are a bit different than the ones shown above. In this case John H. was kind enough to put together an 8-step sequence on how to get to the batteries on the Remington M280 M290 style razors: