Alternative Propulsion Thread

[George Wade]

Originally Posted by GordMay

Anhydrous Ammonia (NH3) ~ is ... readily obtained and handled in liquid form.....
That is to say, a cubic meter of liquid hydrogen contains 71 kg of hydrogen, compared with 105 kg of hydrogen for a m3 of liquid anhydrous ammonia.

..... quickly turns to a gas when exposed to air. More ➥ Green NH3 ( Ammonia )

Promising as a liquid fuel: Equally promising as half of an intense smoke screen and hard to breath deterrent for unwelcome boarders. Three for the price of one.

[fastcat435]

Something I picked up today regarding Lithium Iron Phosphate batteries
Researchers at Carnegie Mellon Electricity Industry Center have concluded that a PHEV pack comprising lithium iron phosphate cells would incur little capacity loss from combining vehicle-to-grid (V2G) activities with regular driving. Statistical analyses indicated that rapid battery cycling incurred when driving degraded the cells more than slower, vehicle-to-grid galvanostatic cycling.

Scott Peterson, Jay Apt, and Jay Whitacre also found that the percent capacity lost in the cells (they used A123Systems 26650 M1 cells, which are used in the Hymotion PHEV conversion packs) per normalized Wh or Ah processed is quite low even based on just use in a dynamic driving cycle—more than 95% of the original cell capacity remained after thousands of driving days worth of use. However, in a companion paper assessing the economics of V2G for consumers, they also concluded that the maximum annual profit for a PHEV owner to engage in V2G (~$10-$120) would likely prove insufficient to encourage use of the battery pack for grid electricity storage and later off-vehicle use.

[ctsbillc]

Slow charge is what we get from the prop or solar on a boat of course.

Hybrid drive makes a lot more sense for a boat than on a car.

[fastcat435]

You are right , I have yet to see the car that can recharge itself.
Maybe in the far future when solar panels reach 30 to 40 % efficiency and can be glued on to the cars surface or PV foil on the windows that it becomes possible,
With a sailing yacht given the large surfaces available for solar panels, wind generation and the regeneration from props while on the move make it possible now.

[Captain Bill]

Originally Posted by ctsbillc

Hybrid drive makes a lot more sense for a boat than on a car.

I'm not sure I understand this statement. My understanding of why hybrid cars were more efficient was that hydrids ran off of electricity while demand was low(no idling in traffic) and reused energy from their momentum (regenerative braking), making them more efficient in stop and go traffic. Most if not all of these vehicles have a higher city cycle milage rating than a highway rating because of this. In fact some have a lower highway rating than their non-hybrid versions. In sailboats one essentially uses the engine for getting in and out of a harbor/marina (Harbor Cycle) or cruising( Cruise Cycle) when the wind doesn't blow. A totally electric drive is a possible solution for the "harbor cycle" but the energy demands for the cruise cycle would seem to be a bit much requiring onboard electricity generation for anything more than a few hours. I find it hard to see how changing mechanical energy to electrical energy and back to mechanical energy doesn't incurr more losses than using the mechanical energy directly. While in harbor mode when loads may be changing rapidly I can see that pulling a bit of extra power from the batteries might help, I would think that in the cruise mode you would loose more than you gain. I was thinking that of course I do harbor mode more often than cruise mode, but in reality it is just more instances not more time. Typically I use the engines for 20 minutes or less each direction in harbor mode. Even if I go out sailing 20 times a year for day sails it just barely equals 1 day on a passage in cruise mode. I can see that I might be able to use electric drives for all of the harbor mode usage, but it would have never taken me from Georgia to NC on a glassy smooth ocean. Of course when I become a full time cruiser and don't have a schedule to keep maybe I won't care.

[bill good]

I've just installed 2X200W panels on my davit top & even at 6kts boat speed into 20kt wind I find there is enough salt water on the panels to need to wash them down & my boat is not wet boat!! Also the sail shades the panels. So solar is not the answer for me under way on a sail boat. Good when not sailing!! Might have put the f'ward on the deck with more pre thought.

[fastcat435]

Hallo Bill
The location of the solar panels is very important to get maximum usage out of them.
Having them as far away from boom and sails is necessary for them to function optimally.
keeping them clean is essential but a bit of salt water spray will lower the efficiency but only a little. On our cat the Bimini is almost 6 meters wide and the panels are placed as far from the boom as possible. the real break thru will come when we can have sails made with PV material and that will not be long, imagine having 80 square meters of pv with lets say 10 % efficiency or 8000 watt per hour for 6 hours per day !!
In case of the Green Motion system most of the generation takes place with the electric motors providing 1 to 4 kw per hour each.

[Factor]

Originally Posted by fastcat435

You are right , I have yet to see the car that can recharge itself.

Havent heard of KERS? (formula 1 cars)

[fastcat435]

Yes I have but it is still not perpetual mobile or recharging with out any fossil fuel !!

[Captain Bill]

Fastcat, 80 square meters of solar panels sound wonderful but I own a catamaran and my sails are always vertical and actually present very little surface area to the sun during peak solar hours (0900-1500) I suppose I would be able to take advantage of those early morning and late evening hours I don't get to use now. I guess there are times when it's an advantage to own one of those tilty boats. You guys aren't proposing to start building your boats so they tilt are you? Maybe a mast that tilts to follow the sun would work?

The way I calculate it, my cat requires about 40 KW or 30 HP to maintain 6 knots, I would therefore need 40 kilowatt hours to cruise at 6 knots for 1 hour, or be collecting 40 KW from my solar panels. Even if the electric motors were twice as efficient as my diesels(no transmission losses etc.) I would still need 20KW. At 10% efficiency (actually a quite high average as solar panels are rated only perpendicular to the sun)I would need 200 square meters to move my boat at cruise speed. I could of course store some of that energy in a battery bank while sitting at anchor for a long period. I calculate it would take 16 4d AGMs to hold that much capacity at a 50% maximum discharge rate. If I covered the entire usable upper surface of my boat with solar panels I could get about 50 square meters, so every 4 days I could capture and use enough electricity for 1 hour of cruising. Even if I stored electricity generated from the motor when I was sailing I could still only cruise for 1 hour. I could of course increase the storage capacity by adding more batteries. Those batteries weigh abot 2000 lbs per group of 16. So if I wanted to be able to cruise for 5 hours I would need about 10000 Lbs of batteries ( even batteries with twice the storage capacity/lb as lead acid would weigh 5000Lbs). That should inhibit my sailng performance just a bit. Of course it would take me 20 days to charge these batteries so I could still only cruise for 5 hours every 20 days. There is actually still a bit of debate on the lifetime efficiency of solar panels, that is that current technology requires more fossil energy to construct than they will collect in their lifetime. My diesels on the other hand weigh about 1000 Lbs and using approximately 600 Lbs of fuel will produce 6 Knots on my boat for about 100 hours and I still get to use my deck. I don't think that solar electric propulsion even when augmented by regeneration while under sail will ever make a practical substitute for a fossil fueled engine in the cruise mode. I think the solution is the use of alternative fuels such as biodiesel to power these engines so that their use is carbon neutral.

The most advantageous alternative propulsion invention I can think of would be a sail configuration that allows one to go directly into the wind, since a major reason I use my engines is that the wind is usually coming from where I am going.

[fastcat435]

Once you have your alternative propulsion working I am looking forward to use it , in mean while I will use our system, you must have a huge cat since we only use 12 KW to get to 6.5 knots on our 45 ft version, Solar panels do not work of the sun but of light and even if the light falls in at an angle of for instance 70 degrees the will still give a lot of power
we have tried and tested many configurations and once available as sails it will work well.

Greetings

Gideon

[ctsbillc]

Currently (or should it be voltagely?) it would seem hybrid is great for getting out of harbour. The difference from cars is, as stated, no regen from braking and no idling at stop lights, but instead we have regen from solar and regen from the props when sailing. Solar tech is still pretty young. Here's what is coming: Sharp solar cell sets Conversion Efficiency record 35% efficient cells are now in the lab, and in a decade probably everyone will be using them.

There is nothing wrong with using a generator, of course, the efficiency can be high if done correctly, (80% for the generator, and 90% for the controller/motor) This is not as good as putting a prop straight onto the back of a diesel via a few spur gears, each of which are 98% efficient, but the electric drive has the advantage of efficiently matching the needs of the prop at all times, plus you are getting the solar regen all the time, which helps redress this.

Neat stuff :-)

[fastcat435]

Thanks for the info on the Sharp solar cells, so far 42 % has been reached but only with high tech units meant for satellite's with magnifying and concentrator cells
Solar Cell Breaks the 40% Efficiency Barrier - Renewable Energy World

getting the efficiency to 35 % plus in triple-junction compound solar cells is a real breakthrough and will help in getting the hybrid technique further

gideon

[Dedzaboy]

Originally Posted by fastcat435

you must have a huge cat since we only use 12 KW to get to 6.5 knots on our 45 ft version,

Theoretically, right?

[Captain Bill]

Our cat is 43.5 feet, but definitely a condomaran, not a performance cat. Mine is an estimate, not a measurement. It is based on my engine BHP, not measured at the prop. Electric motors deliver a much higher percentage of their power to the prop, since they are not typically driving alternators annd cooling pumps. I have no way of making a direct measurement of the KW used to actually move the boat. If I was using an electric motor a simple measurement of voltage and amperage at cruise speed would tell me how many KW it was taking to maintain that speed.