Homestead mailing list

["WILLIAM JONES" <billj AT harborside.com>]

Last night I tried to find to find a pic online of the ridiculous solar heat 
engine built by the Mythbusters, the one that let all the light pass right 
through.  No luck, but in the process I did get to see a diagram of the Minto 
wheel, as described by Don.  Indeed, propane in tanks should become less 
heavy when it vaporizes, because it's somewhat buoyant in air in gaseous 
form, compared to the liquid.  But it's a tough call, to see how the canister 
will be much lighter when heated, whereas the buoyant force provided by air 
pushed underwater is tangible and strong.
As I once stated, because of revelations provided by folks on this list, I 
gave up long ago on any system involving vaporization of a solvent.  The 
added energy cost of that "heat of vaporization" makes it all a losing 
proposition.  That's why the bottle of Fluoroclean lies unopened on the 
shelf.  The other reason is just the high specific heat capacity of these 
heavier fluids.
One thing the Minto wheel has in common with my system is that there's no 
"displacer".  Instead of moving gas between hot and cold ends of a cylinder, 
both systems move the containers themselves from the heat source to the cold 
source.  Both systems rely on symmetry so that this move requires almost no 
energy.  But with heavy propane tanks, it would have to be quite precisely 
made, or all the energy would go into just turning the wheel itself.  Mine is 
just made of ultra-light plastic trash, so no such problem.
But the real revelation is about cost.  I'm guessing that because of the long 
cycling time, my system and the Minto wheel both turn about once or twice a 
minute.  That's no problem if you know about the Spiral Manometer, since as 
long as the swivel valve doesn't leak, it will relentlessly push the water 
through and get the job done, even if it's slow.  All the water will be 
raised to a storage pool anyway.  So it's all good, from that point of view.  
However, the cost of heavy propane tanks is only a zillion times more than 
2-liter bottles from the dumpster.  It's hard to reckon the cost of a bottle, 
a nickle at most.  The cost of combining their flows into one big flow 
depends a lot on how you do it.  If I use trash like used disposable gloves 
and old garden hose to build a manifold, instead of fancy T-connectors, I 
think I can keep the cost at a buck or two per watt, if each bottle costs a 
nickle or so to rig up, and produces 1/20 of a watt or so, although filling 
the bottles with hydrogen or helium would vastly increase that power output.  
I'd guess that the Minto wheel costs ten times that much per watt.  The best 
result I've seen from solar panels is about $5 per watt, but of course you're 
not done yet, unless someone knows a way to make water rise simply by passing 
an electric current through it.  The pump you'll need will squander a goodly 
portion of that power just in heating up its own coils.  By contrast, when I 
give an estimate of power output, it's actual mechanical power.
Yesterday we painted 12 bottles black on half the inside.  The silver spray 
paint on the outside is probably not necessary, and may even hinder in the 
cooling phase, but hey, we already have a can of it and it goes a long way.  
This model will have 12 chambers and 12 floats.  I found it easiest to make 
two "six-shooters" and place them end-to-end, staggered, so that the angular 
distance between floats is 30 degrees.  This evens out the torque, which is 
very important, since the minimum torque is all you get credit for.  In other 
words, with no flywheel to store rotational energy, the system would stop the 
moment the torque required exceeds the torque produced.  It just wouldn't be 
able to get over the hump, so to speak.
Full speed ahead...
Ex occidente lux!!!!!