Thread: What lousy weather!!!!!!

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Jerry Clayton: That is a very interesting question about removing energy from the air with windmills. I will go out on a limb, noting there are some other science folks here, and take an overview crack at it. First, you are correct that the energy has to come from somewhere and that the energy of the atmosphere is related to it's temperature. As a Chemist I am used to thinking in terms of calories, kilocalories, joules and kilojoules while the power folks use kilowatt-hours. For a very easy approach we can use the equation that the energy of gas molecules is:

E = (3/2) R T and delta-E = (3/2) R (delta-T)

where R=1.987 cal/degK mole and T is in absolute Kelvin degrees (1.8 times larger than 1 degree F). So for every 1 kilojoule (1 Joule = 4.184 calories) taken out of the air we have roughly:

delta-T = (2/3)(delta-E/R).

Of course there will be a greater loss due to friction in the windmill so this is only a rough estimate. R in Joules is 8.314 Joules/deg.K mole and at 1 atmosphere 1 mole of air is about 22.414 Liters (about 5.924 gallons). So suppose delta-E is 1 kilojoule.

delta-T = (2/3)(1000 joules/8.314 joules/deg.K-mole)

delta-T = 80.186 degrees K mole for every 1 kilojoule or

(delta-T per 5.824 gallons swept) = 80.186 degrees K. (negative)

The extreme questionable catch here is how many moles (5.924 gallons) of air is actually swept by the blades and I have no way to figure that. All I can say is that yes the air should cool a bit behind the windmills but probably only a few degrees on a large scale. This is made more complicated by the fact that air molecules are traveling at about 1100 mph microscopically at 1 atmosphere but even so we know that bulk air is a fluid and it takes time for pressure fronts to travel in the weather reports so the "other air" would rapidly fill in behind the blades. As a macroscopic observation I recall from a few days ago that the "day" was incremented by 1 second (or was it a millisecond? anyway the rotation of the Earth is slowing) this year so over a very long time the rotation of the Earth is slowing. Since normally tall mountains provide air resistance to the rotation of the Earth, what we are talking about is adding air resistance to the rotation of the Earth. We need the help of an Aeronautical Engineer with knowledge of blades; a helicopter designer. Simply put I would say that yes there has to be some cooling but probably not much.

Stovens: I agree that the Phytoplankton could help the rain forests in converting CO2 to O2 but I have looked at that data and done calculations on that situation. The problem is that Phytoplankton need iron to make their key energy converting heme groups and when winds off of the Gobi or Sahara bring iron-containing sands into the ocean Phytoplankton flourish but if you try to seed them with iron filings or iron sulfate the amount of iron is staggering. In one of my courses we tried to estimate how much the iron concentration of the Pacific could be increased by just 1 ppm assuming the Pacific is uniformly 1 mile deep and using the area between Alaska, Japan, Australia and the West Coast of North and South America and converted that to cargo ship loads in tons of pure iron filings and I forget the actual number but it was in many thousands of cargo ships completely filled with iron filings! So tests where iron filings or iron sulfate are added to sea water show tremdous increases in Phytoplankton in say a 500 gallon tank of sea water are interesting but the Pacific Ocean is HUGE! When you start messing around thinking about Earth-sized quantities of mass or energy you realize the Earth is huge in scale relative to our household quantities. For a chemist used to thinking in terms of liters or gallons, the volume of 1 cubic mile of seawater is amost an unimaginable amount!

Dave S. mentioned a key factor as the age of some of us, but I think some of us will be around to see electric cars.

Don Shillady
Retired Scientist/teen rodder