My dad came down today, and we got a lot done.
2.5 of the 3 lower manifolds are now complete, and the fountain plumbing is now good enough for the pool rebar to be installed. This is great news because it means I am nearly released from the critical path and we can go from having one amateur working two days a week to maybe three or four professionals working 5 days a week. I expect a speedup of at least 7 times!
The bottom manifolds are made of flexible PVC pipe. This stuff is made with two different plastic formulations coextruded. The first is rigid white PVC, just like regular pipes are made of, which is formed into a spiral. The seconds is flexible PVC (with Phthalate mixed in for flexibility), which fills the gaps between the coils. This stuff is a little tricky to work with.
The first problem is that the pipe arrives in coils. By the time you get it, the stuff has achieved something of a permanent bend. I was able to take most of this out by unwinding the stuff down the middle of the pool, where it got hot in the sun for a week.
I have not determined a good way to cut the flexPVC. I'm using my miter saw to cut my pipe, because it makes such nice clear burr-free cuts on the regular PVC pipe. On the flexible stuff it leaves a hot, smoking cut with lots of burrs that I clean up with a knife. The Phthalate is particularly annoying, because our chickens love to eat the PVC chips from the saw, and we eat the chicken eggs, and phthalate is bad stuff. So, the chickens are cooped up on days when I'm cutting flexPVC, and I vacuum up everything afterwards.
We're also having difficulty just measuring the stuff. Somehow we're making lot of mistakes where we measure, cut, and then find that it's not the right length. I think the basic issue is that we're trying to measure curved paths with a tape measure.
Joints are a little scary with the flexPVC pipe. I had a professional plumber recommend that we encase every flexible PVC pipe joint in concrete. Now that I've done a bunch, I agree. If there is any bending load on the joint when it's made, the pipe sits in the socket at an angle, and in a few of those joints I can feel that the PVC glue has not completely filled the space between pipe and socket. I made most of the joints with no load while it was curing, and let them sit for at least a day before putting load on them. Those joints I'm quite comfortable with.
Dad points out that if I have a few leakers, the leak rate will be very low due to the concrete barrier and very low pressure in the system (3-6 psi). The plan is to pressure test before gunite, but that is going to be hard to pull off. I'm concerned I'm going to have leaks in the plastic membrane which collects the water, and this will hide any leaks in the piping.
Sunday, March 29, 2009
Wednesday, March 25, 2009
Sunday, March 22, 2009
Energy plans are like ..., well, everybody's got one. Today I'll be looking at Zubrin's plan, as presented by Anne Korin. Check out her youtube presentation.
Anne likes Robert Zubrin's plan of making lots of ethanol from corn or sugar, and using that instead of oil to run our cars. Digging below the surface, the bottom line is that in 2008 we used 42% of our corn crop to reduce oil imports by 3.7%. So, we aren't going to replace a substantial amount of oil imports this way. But Anne didn't get into that aspect.
Anne's politics are certainly different than mine. She likes to talk about having little or no government, and letting the free market work. At the same time, the present crisis is so very bad, and OPEC is removing freedom from the oil market, so she says we need the government to fix it. Okay, so she's libertarian except when things are bad. A governing system that only works in good cases doesn't sound very robust to me, but that's not really the point of this blog post.
Another issue I have with her otherwise excellent presentation is that I don't follow how OPEC, which controls about half of the oil supply, can remove freedom from the market. You can read a detailed analysis at WTRG Economics which suggests that OPEC does not have even rough pricing control.
But I think this is just her ideology, and I don't care about that so much. What is more interesting is her presentation of Zubrin's plan (unattributed) for fixing our balance of trade / economic insecurity problem.
The basic idea in the Zubrin plan is to mandate that all cars sold in the US accept both alcohol and gasoline fuels. This change can be applied to all cars sold within a couple of years because it does not require large changes by auto manufacturers (contrast with hybrids, or plug-in hybrids, which have a much longer and more expensive adoption curve). Having made that change, within a few years a substantial number of consumers will be able to use high-alcohol-content fuels.. When alcohol is cheaper than gas, gas stations will offer alcohol, and so consumers will have an economic alternative to gasoline.
We can make alcohol from corn or coal, or we can import alcohol fuel. There are a lot of hazy details: corn-ethanol may be soaking up so much corn that we're starving people to death worldwide, corn may be crowding out the use of land for food, and it may be impossible to grow enough corn to matter.
The flex-fuel vehicle part sounds really good. There are a few other details which sound really good to me as well:
- Eliminate the tax on imported ethanol, so that it competes with imported oil (which has no tax).
- Eliminate the tax on imported sugar. Sugar cane is supposed to be a better feedstock for ethanol production than corn.
In the presentation above, one of the audience members asks if ethanol from corn replaces more oil than it consumes. Anne says yes, and it appears she is right. Here's a study of corn-ethanol production efficiency:
- Each BTU of corn-ethanol produced in the U.S. requires an average of 0.14 BTU of gasoline, diesel and fuel oil.
- This factor does not support the conclusion at the top of the study, that each gallon of ethanol displaces 7 gallons of imported oil.
- Correcting for the energy density of ethanol and gasoline, each gallon of ethanol produced domestically displaces 0.57 gallons of imported gasoline.
- The U.S. produced 13 billion gallons of ethanol in 2008, which displaced 7.36 billion gallons of gasoline, and reduced oil imports by 167 million barrels. We imported 4.39 billion barrels over the same period, so the oil imports reduction was 3.7%.
- The U.S. used 5.1 billion bushels of corn in 2008 to make that ethanol, which was 42% of the total of 12.3 billion bushels grown that year.
Bottom line: we aren't going to displace more than, say, 10% of our oil imports in the future by using corn ethanol. There just isn't enough corn.
The reason the question gets asked is that there is a different issue: does making corn ethanol yield more fuel energy than fossil fuel energy used? The answer here is: it's close. When you make ethanol, you make electricity along with it. When you add in the energy value of the coproducts, a little more energy comes out than fossil fuel energy went in (this energy was supplied by the sun).
So, the right way to think of ethanol production is as a coal-to-liquids system. It has the consequence of increasing the total amount of carbon dioxide emitted for a given amount of energy delivered to the automobile.
Thursday, March 19, 2009
The guys at work are calling it my nuclear reactor.
Thanks, Ryan and Wes!
Monday, March 16, 2009
Over the last few years, AIG sold insurance against defaults on mortgage back securities. They sold huge amounts of this insurance, at low prices. Those insurance contracts call for AIG to post bonds which show the ability for AIG to pay, should it's credit rating drop.
Now, because it is supposedly in the U.S. taxpayer's interest that the folks who bought this insurance not suffer any loss, our bailout money is being used to post those bonds. Furthermore, the people at AIG who misestimated the likelihood of defaults on mortgages, and thus mispriced the insurance, are being paid huge bonuses, again with my money.
AIG's position is that both the bonds and the bonuses are required to be paid by contracts that AIG signed. Those contracts cannot be abrogated.
Complete crap. Those contracts can't be abrogated by AIG. There is no such contractual obligation on the U.S. government. AIG is failing. If we let it fail, part of the bankruptcy proceedings will be that some entity, possibly the government, will purchase some portion of the assets. They make take on some of the liabilities if they so choose, as well. So, during the bankruptcy proceeding, the government can negotiate with the folks who have claims on AIG's assets to determine what percentage, if any, of those liabilities the government chooses to fulfill.
Since every serious person involved understands this already, the government can renegotiate those credit default swaps even without AIG going bankrupt. This is called a workout, and it happens between creditors and debtors all the time. If the debtors don't like the proposed workout, they can force the company into bankruptcy.
As part of this workout, we can reduce the bonuses to the folks that sold the credit default swaps to zero. If this causes them to be unable to afford their current homes, that is karmic justice. My guess is that if outraged AIG salespeople attempt to recover a portion of their bonuses by forcing AIG into bankruptcy, they'll be either shot down by a reasonable judge, or just lynched.