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Originally Posted by ITD
{snip}Economy, I'm not sure present hybrid technologies are capable of keeping up with the high power demand of pushing a boat, and if it is will it be more efficient? ... {snip}
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To clarify my prior post .... I suspect you could make a hybrid boat along the lines of Honda's Integrated Motor Assist (IMA) quasi-hybrid technology. Take a given boat the has a top speed of say 50 mph but is used 90% of the time at cruising speeds of 35-40 mph. Replace the "big" engine with a smaller one that runs near WOT at 40 mph and you'd realize some fuel savings in normal cruising usage whilst giving up the ability to run faster than 40 mph. The rub is such a beast might not have enough umph to plane in a reasonable time so you'd add an electric motor, running off batteries right now, to help for the 3 - 10 secs it takes to plane. You drain the batteries to get on-plane. They get recharged at a later time when cruising. If the total weight of the EM plus batteries plus "small" engine is less than or equals the weight of the "big" engine you'll save some fuel for the top end trade off. I suspect it won't be a large savings for the reasons I listed previously. If the hybrid weight exceeds the conventional weight (as it does in autos) then the added drag caused by sitting lower in the water (at the same cruising speeds) will reduce and possibly eliminate the fuel savings. I don't know where a real boat would ends up on this slope.
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Originally Posted by APS
Don't the "auto-tracking" capabilities of solar arrays need to enter this equation (hopeless as it would appear from your figures)?
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My quickie analysis was for a static array but if you want a tracking array I'd say it helps .... but not enough to make the 10 x 10 anything but a dream from a special pipe. Consider that if you lay 2 sheets of PV cells flat and next to each other and then rotate them to follow the sun, at some point the 1 behind will fall into the shadow created by the 1 in front. At 45 degrees the blockage is ~ 30%, though the 70% unblocked is now producing near 100% (for it's reduced area). So if at noon you got 1 watt for this sheet, when the Sun settles to 45 deg you get 0.7W vs my earlier case of 0.5W. You could reduce the array size to something like 127 mi on a side. You could separate the tilting PV panels so they don't shadow their neighbors and get near 100% of peak production while the Sun is up but then you're taking up more area than before. Gets you the same 127 mi. Only ways to believe 10 x 10 number here on Earth is .... a) reduce the 70 Quads to a much lower number (have fun) or b) some really powerful psychotropic drugs
Now in space (ala the URL posted way before) you can free yourself from some of these limitations. Just have to get that Moon mining (again please only on the far side
) operation in full swing.
Last topic from me - How about residential cogeneration plants ? Natural gas is available on a lot of streets so why not have "every" home make it's own electricity from NG ? The waste heat could be used to heat water and/or the house and/or cool the house ? It's done on larger scales but why not small, household scales ? I think we have a power plant person who visits this forum, maybe he/she can comment ?